Title of Invention	AUTOMOTIVE ALTERNATOR AND METHOD FOR MANUFACTURING THE SAME
Abstract	The rectifying apparatus includes: first and second heatsinks that respectively have: first and second heatsink bases that have been prepared so as to have a tubular body that has an arc-shaped cross section; and radiating fins that are disposed so as to stand on an outer circumferential wall surfaces of the first and second heatsink bases, the first and second heatsinks being disposed approximately concentrically so as to line up radially; and positive-side and negative-side diodes that are mounted onto inner circumferential wall surfaces of the first and second heatsink bases so as to be spaced apart from each other circumferentially, and the first and second heatsink bases are prepared by bending and shaping into circular arc shapes flat plate-shaped base members onto which the positive-side and negative-side diodes have been mounted.

Title of Invention

AUTOMOTIVE ALTERNATOR AND METHOD FOR MANUFACTURING THE SAME

Abstract

The rectifying apparatus includes: first and second heatsinks that respectively have: first and second heatsink bases that have been prepared so as to have a tubular body that has an arc-shaped cross section; and radiating fins that are disposed so as to stand on an outer circumferential wall surfaces of the first and second heatsink bases, the first and second heatsinks being disposed approximately concentrically so as to line up radially; and positive-side and negative-side diodes that are mounted onto inner circumferential wall surfaces of the first and second heatsink bases so as to be spaced apart from each other circumferentially, and the first and second heatsink bases are prepared by bending and shaping into circular arc shapes flat plate-shaped base members onto which the positive-side and negative-side diodes have been mounted.

Full Text	AUTOMOTIVE ALTERNATOR AND METHOD FOR MANUFACTURING A RECTIFYING APPARATUS MOUNTED THERETO BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automotive alternator and a method for manufacturing a rectifying apparatus that can be mounted thereto, and particularly relates to a rectifying apparatus heatsink construction. 2. Description of the Related Art In first conventional rectifying apparatuses that can be mounted to an automotive alternator, a radiator that is configured into a single part that is formed by linking two arms into a V shape, and that has fixing lugs at respective end portions of the V shape thereof is fixed to a rear bearing by screws or tie rods that are passed through the respective fixing lugs, and is disposed inside a case of the automotive alternator. The arms between the fixing lugs each have^ a base; a plurality of radiating fins that are disposed so as to line up in a longitudinal direction of the base such that each projects radially inward from the base and extends axially; and a wall that projects radially outward from a flat back surface that is parallel to an axial direction radially outside the base, and that extends in a direction that is perpendicular to an axial direction, and diodes are brazed onto a surface of the wall that is perpendicular to the axial direction (See Figure 9 of Patent Literature 1, for example). In second conventional rectifying apparatuses that can be mounted to an automotive alternator, two radiators that each have fixing lugs at two ends are fixed to a rear bearing by screws or tie rods that are passed through a pair of stacked fixing lugs and two remaining fixing lugs, and are disposed inside a case of the automotive alternator in a V shape. The radiators each have: a base; and a plurality of radiating fins that are disposed so as to line up in a longitudinal direction of the base such that each projects radially inward from the base and extends axially, and diodes are brazed onto a flat surface that is parallel to an axial direction radially outside the base (See Figures 3 and 4 of Patent Literature 1, for example). Patent Literature i: Japanese Patent No. 4187647 (Gazette) In the first conventional rectifying apparatuses, because the radiator is disposed inside the case of the automotive alternator so as to position the shaft inside the V shape, outside diameter dimensions of the radiator are restricted by inside diameter dimensions of the case. Because the wall for mounting the diodes projects radially outward from the flat surface that is parallel to an axial direction radially outside the base, the radial position of the base must be offset radially inward by an amount proportionate to protrusion of the wall. Thus, one problem has been that radial height of the radiating fins is reduced, reducing heat radiating area and lowering cooling capacity of the radiator. In the second conventional rectifying apparatuses, on the other hand, because the diodes are mounted to flat surfaces that are parallel to an axial direction radially outside the base, the base can be offset radially outward compared to the first conventional rectifying apparatuses. Thus, radial height of the radiating fins can be increased, increasing heat radiating area and raising cooling capacity of the radiator. However, because the second conventional rectifying apparatuses are configured so as to be divided into two radiators, one problem has been that the number of parts is increased, reducing ease of assembly. SUMMARY OF THE INVENTION The present invention aims to solve the above problems and an object of the present invention is to provide an automotive alternator and a method for manufacturing a rectifying apparatus that can be mounted thereto that can expand heat radiating area by using installation space inside a case efficiently, and that can be assembled easily without parts being increased in number. In order to achieve the above object, according to one aspect of the present invention, there is provided an automotive alternator including: a case; a rotor that is disposed inside the case so as to be fixed to a shaft that is rotatably supported by the case; a stator that is disposed so as to be supported by the case so as to cover an outer circumference of the rotor, and that is formed by mounting a stator coil to a stator core; a rectifying apparatus that is disposed at a first axial direction side of the rotor inside the case, and that is electrically connected to the stator coil so as to rectify alternating current that is generated in the stator coil into direct current; and a fan that is fixed to an end surface of the rotor at the first axial end. The rectifying apparatus includes^ two heatsinks that each have: a heatsink base that has been prepared so as to have a tubular body that has an arc-shaped cross section; and a plurality of radiating fins that are disposed so as to stand on at least one of an inner circumferential wall surface or an outer circumferential wall surface of the heatsink base, and that extend axially, the two heatsinks being disposed approximately concentrically relative to a central axis of the shaft so as to line up radially; and a plurality of rectifying parts that are mounted onto the inner circumferential wall surface or the outer circumferential wall surface of the heatsink bases so as to be spaced apart from each other circumferentially. Further, the heatsink bases are prepared by bending and shaping into an arc shape a flat plate-shaped base member onto which the plurality of rectifying parts have been mounted. According to the present invention, a heatsink base is prepared by bending and shaping a flat plate-shaped base member into an arc shape. Thus, a tubular heatsink base that has an arc-shaped cross section that can increase the heat radiating area can be prepared easily without having to use processing methods that have inferior yield such as extrusion, or milling, etc. The heatsink can be prepared as a single part, suppressing increases in the number of parts. Because a flat plate-shaped base member onto which the rectifying parts have been mounted is bent and shaped, mounting of the rectifying parts onto the base member need only be performed in a direction that is perpendicular to the front surface of the base member, facilitating assembly of the rectifying apparatus. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a longitudinal section of an automotive alternator according to Embodiment 1 of the present invention; Figure 2 is a side elevation of a rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention; Figure 3A is a side elevation that explains a configuration of a diode that can be used in the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention; Figure 3B is a plan that explains the configuration of the diode that can be used in the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention; Figure 4A is a process diagram that explains a method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention; Figure 4B is a process diagram that explains the method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention," Figure 4C is a process diagram that explains the method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention,' Figure 5A is a process diagram that explains the method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention; Figure 5B is a process diagram that explains the method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention; Figure 5C is a process diagram that explains the method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention; Figure 5D is a process diagram that explains the method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention; Figure 6 is an electrical circuit diagram for the automotive alternator according to Embodiment 1 of the present invention; Figure 7A is a partial side elevation that explains a method for manufacturing a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 2 of the present invention; Figure 7B is a partial side elevation that explains the method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 2 of the present invention; Figure 8 is a side elevation of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 3 of the present invention; Figure 9 is a side elevation of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 4 of the present invention,* Figure 10 is a partial side elevation of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 5 of the present invention; Figure llA is a partial side elevation that explains a method for manufacturing a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 6 of the present invention; Figure llB is a partial side elevation that explains the method for manufacturing the second heatsink assembly of the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 6 of the present invention; Figure 12 is a side elevation of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 7 of the present invention," Figure 13A is a side elevation that explains a configuration of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 8 of the present invention; Figure 13B is a cross section that explains the configuration of the second heatsink assembly of the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 8 of the present invention; Figure 13C is an exploded projection that explains the configuration of the second heatsink assembly of the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 8 of the present invention; Figure 14 is a partial cross section of a vicinity of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 9 of the present invention,' Figure 15 is a partial cross section of a vicinity of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 10 of the present invention; Figure 16A is a side elevation that explains a method for manufacturing a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 11 of the present invention,' and Figure 16B is a side elevation that explains the method for manufacturing the second heatsink assembly of the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 11 of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Figure 1 is a longitudinal section of an automotive alternator according to Embodiment 1 of the present invention, Figure 2 is a side elevation of a rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention, and Figures 3A and 3B are diagrams that explain a configuration of a diode that can be used in the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention, Figure 3A being a side elevation and Figure 3B being a plan. Figures 4A through 4C are process diagrams that explain a method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention, Figures 5A through 5D are process diagrams that explain the method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention, and Figure 6 is an electrical circuit diagram for the automotive alternator according to Embodiment 1 of the present invention. In Figure 1, an automotive alternator 100 includes: a case 1 that is constituted by a front bracket 2 and a rear bracket 3 that are each made of aluminum so as to have an approximate cup shape; a rotor 15 that is rotatably disposed inside the case 1 such that a shaft 18 is supported by means of bearings 4 in the case i; a pulley 5 that is fixed to an end portion of the shaft 18 that projects outward at a front end of the case i; fans 6 that are fixed to two axial end surfaces of the rotor 15; a stator 12 that is fixed to the case 1 so as to surround an outer circumference of the rotor 15 so as to have a constant air gap relative to the rotor 15; a pair of slip rings 7 that are fixed to a rear end of the shaft 18, and that supply current to the rotor 15; a pair of brushes 8 that slide on surfaces of the respective slip rings 7; a brush holder 9 that accommodates the brushes 8; a rectifying apparatus 20 that is electrically connected to the stator 12 so as to convert alternating current that is generated by the stator 12 into the direct current; and a voltage regulator 11 that is mounted onto heatsink 10 that is fitted onto the brush holder 9, and that adjusts magnitude of an alternating-current voltage that is generated by the stator 12. The stator 12 includes'- a cylindrical stator core 13; and a stator coil 14 that is mounted to the stator core 13, and in which an alternating current arises due to changes in magnetic flux from a field coil 16 that accompany rotation of the rotor 15. The rotor 15 includes: a field coil 16 that generates magnetic flux on passage of an excitation current; a pole core 17 that is disposed so as to cover the field coil 16 and in which magnetic poles are formed by that magnetic flux; and the shaft 18, which is fitted through a central axial position of the pole core 17. The fans 6 are fixed to the two axial end surfaces of the pole core 17 by welding, etc. Next, a configuration of the rectifying apparatus 20 will be explained. As shown in Figures 1 and 2, the rectifying apparatus 20 includes: positive-side diodes 21 that function as rectifying parts," negative-side diodes 22 that function as rectifying parts; a first heatsink 27 that supports the positive-side diodes 2i; a second heatsink 33 that supports the negative-side diodes 22; and a circuit board 40 that electrically connects the positive-side and negative-side diodes 21 and 22 and the stator coil 14. As shown in Figure 3, the positive-side diodes 21 include: a rectifying element 23 that is configured by forming an n-type semiconductor and a p-type semiconductor into a p-n junction; a copper base 24 that is soldered to a surface of the n-type semiconductor of the rectifying element 23 on an opposite side from the p-type semiconductor; an insulating resin portion 25 that is formed into an approximate parallelepiped by molding the rectifying element 23 and the copper base 24; and a lead terminal 26a of which a first end is connected to the p-type semiconductor of the rectifying element 23 and is extended outward from the insulating resin portion 25, and of which a second end is connected to the circuit board 40. Similarly, the negative-side diodes 22 include-' a rectifying element 23; a copper base 24 that is soldered to a surface of the p-type semiconductor of the rectifying element 23 on an opposite side from the n-type semiconductor; an insulating resin portion 25 that is formed into an approximate parallelepiped by molding the rectifying element 23 and the copper base 24; and a lead terminal 26b of which a first end is connected to the n-type semiconductor of the rectifying element 23 and is extended outward from the insulating resin portion 25, and of which a second end is connected to the circuit board 40. The first heatsink 27 is prepared using a good heat-conducting material such as aluminum or copper, etc., has a predetermined axial length (width) and a predetermined radial width (wall thickness), and includes-' a first heatsink base 28 that is bent and shaped into a tubular body that has a cross section perpendicular to an axial direction that is a circular arc shape; a plurality of radiating fins 29 that are disposed so as to stand in a radial pattern at a predetermined pitch circumferentially on outer circumferential wall surfaces of the first heatsink base 28, and that each extend axially; and fixing lugs 30 that are disposed so as to extend radially outward from a first axial edge of first and second circumferential end portions and a central portion of the first heatsink base 28 by being bent into L shapes. Apertures 31 for inserting fixing members such as mounting bolts, etc., are disposed through the fixing lugs 30. In addition, positioning projections 32 project to a predetermined height and extend axially on inner circumferential wall surfaces of the first heatsink base 28 between each of the fixing lugs 30 on two circumferential sides of mounting regions of three positive-side diodes that are disposed so as to have a predetermined spacing circumferentially (hereinafter "diode mounting surfaces"). The positive-side diodes 21 are positioned by the positioning projections 32 so as to be placed on each of the diode mounting surfaces, and are mounted by soldering the copper bases 24. The second heatsink 33 is prepared using a good heat-conducting material such as aluminum or copper, etc., has a predetermined axial length (width) and a predetermined radial width (wall thickness), and includes; a second heatsink base 34 that is bent and shaped into a tubular body that has a cross section perpendicular to an axial direction that is a circular arc shape; a plurality of radiating fins 35 that are disposed so as to stand in a radial pattern at a predetermined pitch circumferentially on outer circumferential wall surfaces of the second heatsink base 34, and that each extend axially; and fixing lugs 36 that are formed on first and second circumferential end portions and a central portion of the second heatsink base 34. Apertures 37 for inserting fixing members such as mounting bolts, etc., are disposed through the fixing lugs 36. The second heatsink base 34 is prepared so as to have an inside diameter that is larger than an outside diameter of the circular arc that is constituted by the projecting ends of the radiating fins 29 that are disposed so as to stand in a radial pattern on the outer circumferential wall surfaces of the first heatsink base 28. In addition, positioning projections 38 project to a predetermined height and extend axially on inner circumferential wall surfaces of the second heatsink base 34 between each of the fixing lugs 36 on two circumferential sides of mounting regions of three negative-side diodes that are disposed so as to have a predetermined spacing circumferentially (hereinafter "diode mounting surfaces"). The negative-side diodes 22 are positioned by the positioning projections 38 so as to be placed on each of the diode mounting surfaces, and are mounted by soldering the copper bases 24. As shown in Figure 2, first and second heatsinks 27 and 33 that have been prepared in this manner are disposed concentrically by placing the fixing lugs 36 and 30 on top of each other with insulating tubes 39 interposed. The first and second heatsinks 27 and 33 are mounted to the case 1 with the circuit board 40 stacked thereon by passing mounting bolts (not shown) through the circuit board 40 and the apertures 31 and 37 and fastening the mounting bolts to an inner wall surface of the rear bracket 3. Here, the first and second heatsinks 27 and 33 are disposed so as to be approximately concentric with a central axis of the shaft 18. The second heatsink 33 is mounted to the inner wall surface of the rear bracket 3 so as to ensure a state of thermal contact, and in a state of electrical connection, and is grounded. The first heatsink 27 is mounted in a state of electrical insulation from the second heatsink 33 and the rear bracket 3. Moreover, the brush holder 9 is disposed between the first and second circumferential end portions of the circular arc-shaped first and second heatsinks 27 and 33. Here, the circuit board 40 is a resin-molded body into which a plurality of inserted conductors are insert-molded, and end portions of the inserted conductors are exposed to constitute connecting terminals. The lead terminals 26a and 26b of the positive-side and negative-side diodes 21 and 22 are connected to the connecting terminals of the circuit board 40, and output wires 41 of windings 14a through 14f that constitute the stator coil 14 are also connected to the connecting terminals of the circuit board 40. Thus, as shown in Figure 6, the rectifying apparatus 20 is constituted by first and second rectifying apparatuses 20A and 20B that are constituted by diode bridges formed by three diode pairs that are made by connecting the positive-side diodes 21 and the negative-side diodes 22 in series. As shown in Figure 6, the stator coil 14 is constituted by a three-phase alternating-current winding 14A that is formed by wye-connecting three windings 14a, 14b, and 14c, and a three-phase alternating-current winding 14B that is formed by wye-connecting three windings 14d, 14e, and 14f, and the respective output ends of each of the windings 14a, 14b, 14c, 14d, 14e, and 14f are connected to connection points between the positive-side diodes 21 and the negative-side diodes 22 of the respective diode pairs. Thus, three-phase alternating-current voltages that are output from the respective output ends of the three-phase alternating-current winding 14A are output so as to be full-wave rectified by the first rectifying apparatus 20A, and three-phase alternating-current voltages that are output from the respective output ends of the three-phase alternating-current winding 14B are output so as to be full-wave rectified by the second rectifying apparatus 20B. Next, action of an automotive alternator 100 that has been configured in this manner will be explained. First, current is supplied from a battery (not shown) to the field coil 16 of the rotor 15 by means of the brushes 8 and the slip rings 7, generating magnetic flux. The pole core 17 is magnetized by this magnetic flux into North-seeking (N) poles and South-seeking (S) poles alternately in a circumferential direction. At the same time, rotational torque from an engine is transmitted to the shaft 18 by means of a belt (not shown) and the pulley 5, rotating the rotor 15. Thus, rotating magnetic fields are applied to the stator coil 14 of the stator 12, generating electromotive forces in the stator coil 14. These alternating-current electromotive forces are rectified into direct current by the rectifying apparatus 20, then charged to the battery, or supplied to an electric load, etc. Here, the fans 6 are driven to rotate due to the rotation of the rotor 15, and cooling airflows are sucked inside the rear bracket 3 through air intake apertures 3a that are disposed through an end surface of the rear bracket 3. Cooling airflows that have been sucked into the rear bracket 3 flow through axially between the radiating fins 29 and 35 and reach the rotor 15. A cooling airflow that has been sucked into the rear bracket 3 also flows radially inward along the heatsink 10, and subsequently flows axially and reaches the rotor 15. The cooling airflows that have flowed to the rotor 15 are deflected centrifugally by the fans 6, and are discharged outside the rear bracket 3 through air discharge apertures 3b that are disposed through side surfaces of the rear bracket 3. Moreover, at the front end cooling airflows are also sucked in through air intake apertures 2a that are disposed through an end surface of the front bracket 2, are deflected centrifugally by the fans 6, and are discharged outside the front bracket 2 through air discharge apertures 2b that are disposed through side surfaces of the front bracket 2. Thus, heat that is generated in the voltage regulator 11 is radiated to the cooling airflow that flows along the heatsink 10. Heat that is generated in the positive-side and negative-side diodes 21 and 22 of the rectifying apparatus 20 is radiated to the cooling airflows that flow through between the radiating fins 29 and 35 of the first and second heatsinks 27 and 33. Heat that is generated in the stator coil 14 is radiated from front-end and rear-end coil ends to the cooling airflows that have been deflected centrifugally by the fans 6. Thus, heat-generating parts that are mounted internally inside the case 1 such as the voltage regulator 11, the stator coil 14, and the rectifying apparatus 20, etc., are cooled, suppressing excessive temperature increases, thereby suppressing deterioration of power generating performance and enabling service life of parts to be extended. According to Embodiment 1, a first heatsink 27 that includes: a first heatsink base 28 that is bent and shaped into a tubular body that has a circular arc-shaped cross section; and a plurality of radiating fins 29 that are disposed so as to stand in a radial pattern on outer circumferential wall surfaces of the first heatsink base 28, and a second heatsink 33 that includes•" a second heatsink base 34 that is bent and shaped into a tubular body that has a circular arc-shaped cross section; and a plurality of radiating fins 35 that are disposed so as to stand in a radial pattern on outer circumferential wall surfaces of the second heatsink base 34, are disposed concentrically, positive-side diodes 21 are mounted to inner circumferential wall surfaces of the first heatsink base 28, and negative-side diodes 22 are mounted to inner circumferential wall surfaces of the second heatsink base 34. Thus, radial width increases in the first and second heatsink bases 28 and 34 are eliminated, enabling radial height of the radiating fins 29 and 35 to be increased. Heat radiating area is thereby increased, enabling cooling capacity of the first and second heatsinks 27 and 33 to be increased, thereby enabling excessive temperature increases in the positive-side and negative-side diodes 21 and 22 to be suppressed. Because the first and second heatsinks 27 and 33 are each constituted by a single member, the number of parts can be reduced, enabling the rectifying apparatus 20 to be assembled easily. Pairs of positioning projections 32 and 38 are disposed so as to extend axially on two circumferential sides of respective diode mounting surfaces on inner circumferential wall surfaces of the first and second heatsink bases 28 and 34 so as to project to a predetermined projecting height. Thus, because positioning of the positive-side and negative-side diodes 21 and 22 is performed by using the pairs of positioning projections 32 and 38 as guides to place the positive-side and negative-side diodes 21 and 22 on each of the diode mounting surfaces of the inner circumferential wall surfaces of the first and second heatsink bases 28 and 34, ease of assembly of the rectifying apparatus 20 is improved. Next, a method for manufacturing the rectifying apparatus 20 will be explained with reference to Figures 4 and 5. First, a second heatsink parent material 55 that is shown in Figure 4A is prepared. The second heatsink parent material 55 includes: a second base member 56 that is prepared so as to have a flat plate shape that has a rectangular cross section that has a predetermined width and a predetermined thickness, and on which fixing lugs 36 are formed at two longitudinal end portions and a central portion; and a plurality of radiating fins 57 that are disposed so as to stand on flat rear surfaces of the second base member 56 so as to be perpendicular and to extend in a width direction, and that are arranged at a predetermined pitch in a longitudinal direction. In addition, three pairs of positioning projections 38 that have a predetermined spacing in the longitudinal direction and that extend in the width direction so as to project to a predetermined height are disposed on respective flat front surfaces of the second base member 56 at a predetermined pitch in the longitudinal direction between each of the fixing lugs 36. Next, as shown in Figure 4B, the negative-side diodes 22 are placed between the respective pairs of positioning projections 38 (onto the diode mounting surfaces) from above the flat front surfaces of the second base member 56. Then, the negative-side diodes 22 are mounted by soldering the copper bases 24 to the front surfaces of the second base member 56. Next, the second base member 56 is bent into a circular arc shape such that the front surfaces of the second base member 56 are on a radially inner side to obtain a second heatsink assembly in which the negative-side diodes 22 are mounted to the second heatsink 33, as shown in Figure 4C. Next, a first heatsink parent material 50 that is shown in Figure 5A is prepared. The first heatsink parent material 50 includes^ a first base member 51 that is prepared so as to have a flat plate shape that has a rectangular cross section that has a predetermined width and a predetermined thickness, and on which fixing lugs 30 are formed at two longitudinal end portions and a central portion? and a plurality of radiating fins 52 that are disposed so as to stand on flat rear surfaces of the first base member 51 so as to be perpendicular and to extend in a width direction, and that are arranged at a predetermined pitch in a longitudinal direction. In addition, three pairs of positioning projections 32 that have a predetermined spacing in the longitudinal direction and that extend in the width direction so as to project to a predetermined height are disposed on respective flat front surfaces of the first base member 51 at a predetermined pitch in the longitudinal direction between each of the fixing lugs 30. The fixing lugs 30 extend from two longitudinal end portions and a central portion of the first base member 51 to one width direction side parallel to the front surfaces of the first base member 51. Next, as shown in Figure 5B, the positive-side diodes 21 are placed between the respective pairs of positioning projections 32 (onto the diode mounting surfaces) from above the flat front surfaces of the first base member 51. Then, the positive-side diodes 21 are mounted by soldering the copper bases 24 to the front surfaces of the first base member 51. Next, as shown in Figure 5C, each of the fixing lugs 30 is bent toward the rear surface side of the first base member 51 into an L shape. Next, the first base member 51 is bent into a circular arc shape such that the front surfaces of the first base member 51 are on a radially inner side to obtain a first heatsink assembly in which the positive-side diodes 21 are mounted to the first heatsink 27, as shown in Figure 5D. Next, as shown in Figure 2, the first heatsink 27 and the second heatsink 33 are disposed concentrically such that the fixing lugs 30 are stacked on the fixing lugs 36 with insulating tubes 39 interposed. Finally, the rectifying apparatus 20 is installed in the case 1 by stacking the circuit board 40 on top of the first and second heatsinks 27 and 33, passing mounting bolts through the circuit board 40 and the apertures 31 and 37 of the fixing lugs 30 and 36, and fastening the mounting bolts to the inner wall surface of the rear bracket 3. Now, conventionally, first and second heatsinks that include"• first and second heatsink bases that have tube bodies that have circular arc-shaped cross sections! and a plurality of radiating fins that are disposed so as to stand in a radial pattern on outer circumferential wall surfaces of the first and second heatsink bases are prepared using processing methods such as extrusion, or milling, etc., and yield has been poor. However, according to the manufacturing method according to Embodiment 1, because the first and second heatsinks 27 and 33 are prepared by preparing first and second heatsink parent materials 50 and 55 that have flat first and second base members 51 and 56 that have a rectangular cross section, and then bending the first and second heatsink parent materials 50 and 55 into circular arc shapes, yield can be improved significantly. According to the manufacturing method according to Embodiment 1, because the first and second heatsink parent materials 50 and 55 are bent into circular arc shapes such that the radiating fins 52 and 57 are oriented radially outward, the radiating fins 52 and 57 can be separated and shaped into a radial pattern, enabling cooling of the first and second heatsinks 27 and 33 to be improved. Conventionally, when diodes are mounted onto first and second heatsinks that have been prepared using processing methods such as extrusion, or milling, etc., the diodes must be mounted onto each of the diode mounting surfaces on the inner circumferential wall surfaces of the first and second heatsink bases of the circular arc-shaped tubular body from a radial direction while moving circumferentially, making the process of mounting the diodes extremely complicated. However, according to the manufacturing method according to Embodiment 1, the positive-side and negative-side diodes 21 and 22 are mounted to the first and second base members 51 and 56 before bending the first and second heatsink parent materials 50 and 55 into circular arc shapes. Thus, mounting of the positive-side and negative-side diodes 21 and 22 need be performed only in a direction that is perpendicular to the flat front surfaces of the first and second base members 51 and 56, significantly simplifying the process of mounting the positive-side and negative-side diodes 21 and 22. In Embodiment 1 above, fixing lugs 30 that extend from the first base member 51 parallel to the front surfaces of the first base member 51 to one width direction side are formed simultaneously during preparation of the first heatsink parent material 50, but the fixing lugs 30 may also be formed so as to be bent toward the rear surface side of the first base member 51 into L shapes simultaneously during preparation of the first heatsink parent material 50. In that case, a step of bending the fixing lugs 30 into L shapes is eliminated, simplifying steps for manufacturing the first heatsink 27. Embodiment 2 Figures 7A and 7B are partial side elevations that explain a method for manufacturing a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 2 of the present invention, Figure 7A showing a state in which a negative-side diode is placed and Figure 7B showing a state in which the negative-side diode is fixed. As shown in Figure 7A, in a second heatsink parent material 55A according to Embodiment 2, fixing hooks 42 are disposed so as to extend in a width direction on front surfaces of a second base member 56 on two longitudinal sides of the diode mounting surfaces in a longitudinal direction so as to project to a predetermined height. Moreover, the second heatsink parent material 55A is prepared in a similar manner to the second heatsink parent material 55 except for the fact that the fixing hooks 42 are disposed instead of the positioning projections 38. As shown in Figure 7B, when the second heatsink parent material 55A onto the second base member 56 of which the negative-side diodes 22 are mounted is bent into an circular arc shape, the fixing hooks 42 lean inward toward the copper bases 24 of the negative-side diodes 22 from the two longitudinal sides such that the negative-side diodes 22 are crimped and fixed to the second heatsink base 34 that is bent and shaped into a circular arc shape. Thus, a second heatsink assembly is obtained in which the negative-side diodes 22 are mounted to the second heatsink 33A. According to Embodiment 2, because the negative-side diodes 22 are crimped and fixed by the fixing hooks 42 in the step of bending the second heatsink parent material 55A, need for a soldering step is eliminated, simplifying the step of manufacturing the second heatsink proportionately. Now, fixing hooks are formed on a first base member in a similar manner in a first heatsink parent material, and positive-side diodes are also mounted to the first heatsink so as to be crimped and fixed by the fixing hooks by performing a step of bending the first heatsink parent material. Moreover, in Embodiment 2 above, the negative-side diodes 22 are placed on the diode mounting surfaces of the second base member 56, and the second heatsink parent material 55A is subsequently bent into a circular arc shape so as to crimp and fix the negative-side diodes 22 to the second heatsink base 34, but the negative-side diodes 22 may also be placed on the diode mounting surfaces of the second base member 56 and crimped and fixed by bending the fixing hooks 42 toward the negative-side diodes 22, and then the second heatsink parent material 55A subsequently bent into a circular arc shape. In that case, because the second heatsink parent material 55A can be bent with the negative-side diodes 22 in a fixed state, the negative-side diodes 22 will not fall out in the bending step, enabling the second heatsink parent material 55Ato be bent simply and stably. In Embodiment 2 above, the negative-side diodes 22 are placed on the diode mounting surfaces of the second base member 56, and the second heatsink parent material 55A is subsequently bent into a circular arc shape so as to crimp and fix the negative-side diodes 22 to the second heatsink base 34, but the negative-side diodes 22 may also be placed on the diode mounting surfaces of the second base member 56 and the copper bases 24 soldered, and then the second heatsink parent material 55A subsequently bent into a circular arc shape. In that case, because the second heatsink parent material 55A can be bent with the negative-side diodes 22 in a fixed state, the negative-side diodes 22 will not fall out in the bending step, enabling the second heatsink parent material 55A to be bent simply and stably. In addition, because the negative-side diodes 22 are fixed to the second heatsink base 34 by soldering and crimping, the negative-side diodes 22 are held on the second heatsink base 34 very strongly. Embodiment 3 Figure 8 is a side elevation of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 3 of the present invention. In Figure 8, fixing lugs 36 are formed at four positions on a second heatsink base 34 that is bent and shaped into a tubular body that has a circular arc-shaped cross section, including two circumferential end portions and portions that divide the second heatsink base 34 into three sections circumferentially. Radiating fins 35 are disposed so as to stand in a radial pattern on outer circumferential wall surfaces of the second heatsink base 34. In addition, a second heatsink 33B is prepared by disposing two negative-side diodes 22 on respective inner circumferential wall surfaces of the second heatsink base 34 between each of the fixing lugs 36, and mounting them by soldering the copper bases 24. Because a first heatsink is also prepared in a similar manner, explanation thereof will be omitted here. Moreover, the rest of the configuration is configured in a similar manner to Embodiment 1 above. According to Embodiment 3, because distances between the fixing lugs 36 are shorter, the operation of bending the heatsink parent material into a circular arc shape is facilitated, and bending stress is also reduced, improving reliability of the second heatsink 33B. Embodiment 4 Figure 9 is a side elevation of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 4 of the present invention. In Figure 9, fixing lugs 36 are formed at three positions on a second heatsink base 34 that is bent and shaped into a tubular body that has a circular arc-shaped cross section, including two circumferential end portions and a central portion. Radiating fins 35 are disposed so as to stand in a radial pattern on portions between diode mounting surfaces on inner circumferential wall surfaces of the second heatsink base 34. In addition, a second heatsink 33C is prepared by disposing negative-side diodes 22 on the respective diode mounting surfaces on the inner circumferential wall surfaces of the second heatsink base 34 between each of the fixing lugs 36, and mounting them by soldering the copper bases 24. Because a first heatsink is also prepared in a similar manner, explanation thereof will be omitted here. Moreover, the rest of the configuration is configured in a similar manner to Embodiment 1 above. Because a first heatsink and a second heatsink 33C that have been prepared in this manner are disposed inside a rear bracket of an automotive alternator concentrically, radiating fins are disposed in a space on a radially inner side where flow velocity is comparatively high, improving cooling performance of the first and second heatsinks. Embodiment 5 Figure 10 is a partial side elevation of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 5 of the present invention. In Figure 10, in addition to radiating fins 35, a second heatsink 33D has auxiliary radiating fins 43 that are disposed on portions between diode mounting surfaces on inner circumferential wall surfaces of a second heatsink base 34 that is bent and shaped into a tubular body that has a circular arc-shaped cross section. Because a first heatsink is also prepared in a similar manner, explanation thereof will be omitted here. Moreover, the rest of the configuration is configured in a similar manner to Embodiment 1 above. According to Embodiment 5, because radiating fins 35 are disposed so as to stand on outer circumferential wall surfaces of a second heatsink base 34, and auxiliary radiating fins 43 are disposed so as to stand on inner circumferential wall surfaces of the second heatsink base 34, the heat radiating area of the second heatsink 33D is increased, improving cooling performance of the second heatsink 33D. Embodiment 6 Figures 11A and llB are partial side elevations that explain a method for manufacturing a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 6 of the present invention. Figure llA showing a state before a step of bending the second heatsink assembly and Figure llB showing a state after the step of bending the second heatsink assembly. As shown in Figure llA, in a second heatsink parent material 55B according to Embodiment 6, a first recessed groove 44 that functions as a bending facilitating portion is disposed so as to extend in a width direction on a central portion between diode mounting surfaces on a front surface of a second base member 56 so as to have a groove direction in a width direction. In addition, second recessed grooves 45 that function as a bending facilitating portion are disposed so as to extend in the width direction on rear surfaces of the second base member 56 so as to have a groove direction in the width direction, so as to avoid regions that face the diode mounting surfaces, and so as to be on two sides of a portion that faces the first recessed groove 44. The first and second recessed grooves 44 and 45 are formed for over a entire region in the width direction of the second base member 56. Negative-side diodes 22 are placed on the diode mounting surfaces on the front surface of the second base member 56, and are mounted to the second heatsink parent material 55B by soldering. Next, the second heatsink parent material 55B is bent into a circular arc shape. As shown in Figure llB, the second base member 56 is then bent at the first recessed grooves 44 and the second recessed grooves 45 to obtain a second heatsink base 34 that is bent and shaped into a tubular body that has an approximately circular arc-shaped cross section. A second heatsink assembly is thereby obtained in which negative-side diodes 22 are mounted to a second heatsink 33E. According to Embodiment 6, because the second base member 56 is easily bent at the first recessed grooves 44 and the second recessed grooves 45 in the step of bending the second heatsink parent material 55B, bending work is facilitated, and stresses that act on soldered portions in the bending step are reduced, enabling reliability of bonding of the negative-side diodes 22 to the second heatsink base 34 to be improved. Here, first and second recessed grooves are also formed on a first base member in a first heatsink parent material in a similar manner, facilitating bending of the first heatsink parent material. Embodiment 7 Figure 12 is a side elevation of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 7 of the present invention. In Figure 12, a second heatsink base 34 is formed into a tubular body that has an angular C-shaped cross section by being bent at right angles at two bend portions. Fixing lugs 36 are formed at three positions of the second heatsink base 34, including two end portions and a central portion of a floor portion. Radiating fins 35 are disposed so as to stand perpendicular to outer circumferential wall surfaces of the second heatsink base 34. Radiating fins 35 are also formed at the bend portions of the second heatsink base 34 in a radial pattern. In addition, first recessed grooves 44 that have groove directions in a width direction are formed at each of the bend portions of the second heatsink base 34. A second heatsink 33F is prepared by disposing two negative-side diodes 22 on each of respective inner circumferential wall surfaces of the respective sides of the angular C shape of the second heatsink base 34 and mounting them by soldering copper bases 24. Because a first heatsink is also prepared in a similar manner, explanation thereof will be omitted here. Moreover, the rest of the configuration is configured in a similar manner to Embodiment 1 above. To prepare a second heatsink 33F that is configured in this manner, a heatsink parent material is first prepared in which first recessed grooves 44 are recessed so as to extend in a width direction at portions that divide a front surface of a second base member 56 such as that shown in Figure 4A into three sections in a longitudinal direction. Next, negative-side diodes 22 are placed on diode mounting surfaces on the front surface of the second base member and soldered. The second base member is sub at right angles at the first recessed grooves 44 to obtain the second heatsink 33F. According to Embodiment 7, a second heatsink 33F is bent and shaped into a tubular body that has a cross section that is a polygon that has two corner portions, and a first heatsink is also prepared in a similar manner to the second heatsink 33F. Thus, because the first and second heatsinks can be disposed so as to extend circumferentially inside a space that surrounds the shaft 18 inside the rear bracket 3, heat radiating area can be increased, enabling cooling performance of the first and second heatsinks to be increased in a similar manner to Embodiment 1 above. Because the first recessed grooves 44 are recessed into the front surface of the second base member at the bend portions, the operation of bending the second heatsink parent material is facilitated, and bending stresses are also reduced, improving the reliability of the second heatsink 33F. Stresses that act on the soldered portions are also reduced in the bending step, enabling reliability of bonding of the negative-side diodes 22 to the second heatsink base 34 to be improved. Moreover, in Embodiment 7 above, the second heatsink 33F is prepared by bending the second heatsink parent material at right angles at two longitudinal positions, but the bend portions of the second heatsink parent material are not limited to two positions, and may also be at four positions, for example. In that case, first recessed grooves are formed at four positions that divide the second heatsink parent material into five equal sections longitudinally, for example, and portions where each of the first recessed grooves are formed should be bent such that interior angles are 135 degrees. Embodiment 8 Figures 13A through 13C are diagrams that explain a configuration of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 8 of the present invention, Figure ISA being a side elevation that shows a state in which a negative-side diode is fixed, Figure 13B being a cross section that shows the state in which the negative-side diode is fixed, and Figure 13C being an exploded projection of a second heatsink assembly. In Figure 13, a copper base 24A of a negative-side diode 22A has a length that is longer than a width of the second heatsink base 34, and is formed so as to have an angular C shape in which two end portions project downward. The negative-side diode 22A is mounted to the second heatsink 33A by being placed between a pair of fixing hooks 42 on the second heatsink base 34 such that flange portions 46 of the copper base 24A project toward a rear surface from two ends in a width direction of the second heatsink base 34, and is crimped and fixed by the fixing hooks 42. The flange portions 46 constitute an axial movement restricting portion. Because a first heatsink is also prepared in a similar manner, explanation thereof will be omitted here. Moreover, the rest of this embodiment is configured in a similar manner to Embodiment 2 above. According to Embodiment 8, the copper bases 24A of the negative-side diodes 22A are formed so as to have an angular C shape. Thus, when the negative-side diodes 22A are placed on the diode mounting surfaces of the second base member of the second heatsink parent material, movement of the copper bases 24A in the longitudinal direction of the second base member is restricted by the pairs of fixing hooks 42, and movement of the negative-side diodes 22 in the width direction of the second base member is also restricted by the flange portions 46 projecting toward the rear surface from the two width direction sides of the second base member. Falling out, or dislodgment, etc., of the negative-side diodes 22 thereby is suppressed when conveying the second heatsink parent material on which the negative-side diodes 22 have been placed within a production line, increasing productivity. Embodiment 9 Figure 14 is a partial cross section of a vicinity of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 9 of the present invention. In Figure 14, a rear end of a first heatsink base 28 of a first heatsink 27G that is bent and shaped into a tubular body that has a circular arc-shaped cross section projects toward an inner end surface of a rear bracket 3 relative to radiating fins 29. A radial position of an outer circumferential surface of a projecting portion 47 at the rear end of the first heatsink base 28 is formed so as to have a tapered shape that gradually becomes lower toward the rear end. A rear end of a second heatsink base 34 of a second heatsink 33G that is bent and shaped into a tubular body that has a circular arc-shaped cross section projects toward an inner end surface of a rear bracket 3 relative to radiating fins 35. A radial position of an outer circumferential surface of a projecting portion 48 at the rear end of the second heatsink base 34 is formed so as to have a tapered shape that gradually becomes lower toward the rear end. The projecting portions 47 and 48 constitute a cooling airflow guiding portion. Air intake apertures 3a are disposed through the rear bracket 3 so as to face the first and second heatsinks 27G and 33G. Moreover, the rest of the configuration is configured in a similar manner to Embodiment 1 above. According to Embodiment 9, air intake apertures 3a are disposed through a rear bracket 3 so as to face first and second heatsinks 27G and 33G, and projecting portions 47 and 48 of first and second heatsink bases 28 and 34 are formed so as to have a tapered shape. Thus, cooling airflows that have been sucked in through the air intake apertures 3a flow along inclined surfaces (outer circumferential wall surfaces) 47a and 48a of the projecting portions 47 and 48 and flow in between the radiating fins 29 and 35. Cooling airflows that have been sucked in through the air intake apertures 3a thereby flow through between the radiating fins 29 and 35 efficiently, improving cooling performance of the first and second heatsinks 27G and 33G. Embodiment 10 Figure 15 is a partial cross section of a vicinity of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 10 of the present invention. In Figure 15, copper bases 24B of positive-side and negative-side diodes 2 IB and 22B have a length that is longer than a width of the first and second heatsink bases 28 and 34, and are formed so as to have angular C shapes in which two end portions project radially outward. Radial positions of outer circumferential surfaces of flange portions 49 at the rear ends of the copper bases 24B are formed so as to have tapered shapes that gradually become lower toward the rear end from positions of outer circumferential wall surfaces of the first and second heatsink bases 28 and 34. The flange portions 49 constitute a cooling airflow guiding portion. Air intake apertures 3a are disposed through the rear bracket 3 so as to face first and second heatsinks 27 and 33, Moreover, the rest of the configuration is configured in a similar manner to Embodiment 1 above. According to Embodiment 10, air intake apertures 3a are disposed through a rear bracket 3 so as to face first and second heatsinks 27 and 33, and flange portions 49 of copper bases 24B of positive-side and negative-side diodes 21B and 22B are formed so as to have a tapered shape. Thus, cooling airflows that have been sucked in through the air intake apertures 3a flow along inclined surfaces (outer circumferential wall surfaces) 49a of the flange portions 49 and flow in between the radiating fins 29 and 35. Cooling airflows that have been sucked in through the air intake apertures 3a thereby flow through between the radiating fins 29 and 35 efficiently, improving cooling performance of the first and second heatsinks 27 and 33. Embodiment 11 Figures 16A and 16B are side elevations that explain a method for manufacturing a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 11 of the present invention, Figure 16A showing a state before negative-side diodes are mounted and Figure 16B showing a state after negative-side diodes are mounted. In Embodiment 11, as shown in Figure 16A, three positioning recessed grooves 58 are recessed at a predetermined pitch in a longitudinal direction on each of respective front surfaces of a second base member 56 of a second heatsink parent material 55C between respective fixing lugs 36. Each of the positioning recessed groove 58 is recessed over an entire region in a width direction of the second base member 56 at a predetermined groove width and at a predetermined depth, and constitutes a diode mounting surface. As shown in Figure 16B, negative-side diodes 22 are placed inside each of the positioning recessed grooves 58, and are mounted by soldering copper bases 24. Next, although not shown, the second base member 56 is bent into a circular arc shape such that the front surfaces of the second base member 56 are on a radially inner side to obtain a second heatsink assembly in which the negative-side diodes 22 are mounted to the second heatsink. According to Embodiment 11, because the positioning recessed grooves 58 are recessed into the front surfaces of the second base member 56, the negative-side diodes 22 can be positioned while restricting longitudinal movement simply by placing the negative-side diodes 22 inside the positioning recessed grooves 58. Thus, the operation of soldering the negative-side diodes 22 is facilitated. Here, positioning recessed grooves are also formed on front surfaces of a first base member in a first heatsink parent material in a similar manner, facilitating an operation of soldering positive-side diodes. Moreover, in each of the above embodiments, positive-side diodes are mounted to a first heatsink that is disposed on a radially inner side and negative-side diodes are mounted to a second heatsink that is disposed on a radially outer side, but positive-side diodes may also be mounted to a second heatsink that is disposed on a radially outer side and negative-side diodes mounted to a first heatsink that is disposed on a radially inner side. It is not absolutely necessary for axial length of the first and second heatsinks to be equal, and the number of radiating fins, or the fin pitch, etc., may also be set appropriately. In each of the above embodiments, positive-side diodes and negative-side diodes are mounted to inner circumferential wall surfaces of first and second heatsink bases, but positive-side diodes and negative-side diodes may also be mounted to outer circumferential wall surfaces of first and second heatsink bases, or positive-side diodes may also be mounted to outer circumferential wall surfaces of a first heatsink base and negative-side diodes may be mounted to inner circumferential wall surfaces of a second heatsink, etc. In each of the above embodiments, three-phase alternating-current windings are explained as being wye-connected, but similar effects are also exhibited if the three-phase alternating-current windings are delta-connected. In each of the above embodiments, six positive-side and six negative-side diodes are mounted onto the respective first and second heatsinks, but the numbers of positive-side and negative-side diodes that are mounted onto the respective first and second heatsinks are not limited to being six. If, for example, the stator coil is constituted by a single three-phase alternating-current winding, and output from the three-phase alternating-current winding is to be full-wave rectified by a diode bridge, then the numbers of positive-side and negative-side diodes that are mounted onto the respective first and second heatsinks will be three. If the stator coil is constituted by a single three-phase alternating-current winding, and output from a wye-connected neutral point is to be full-wave rectified by a diode bridge in addition to the three output ends of the three-phase alternating-current winding, then the numbers of positive-side and negative-side diodes that are mounted onto the respective first and second heatsinks will be four. In each of the above embodiments, first and second heatsink bases are bent and shaped into tube bodies that have circular arc-shaped cross sections, but the shapes of the first and second heatsink bases are not limited to tube bodies that have circular arc-shaped cross sections, and may be any tubular body that has an arc-shaped cross section that extends circumferentially inside a space inside the case that surrounds the shaft, and that has a predetermined axial length. Moreover, a tubular body that has an angular C-shaped cross section, which is the shape of a heatsink base according to Embodiment 7 above, in other words, a tubular body that has a polygonal cross section that has a plurality of corner portions is also included in the tubular body that has an arc-shaped cross section according to the present application. WE CLAIM: 1. An automotive alternator comprising: a case; a rotor that is disposed inside said case so as to be fixed to a shaft that is rotatably supported by said case! a stator that is disposed so as to be supported by said case so as to cover an outer circumference of said rotor, and that is formed by mounting a stator coil to a stator core; a rectifying apparatus that is disposed at a first axial direction side of said rotor inside said case, and that is electrically connected to said stator coil so as to rectify alternating current that is generated in said stator coil into direct current; and a fan that is fixed to an end surface of said rotor at said first axial end, said automotive alternator being characterized in that: said rectifying apparatus comprises: two heatsinks that each have: a heatsink base that has been prepared so as to have a tubular body that has an arc-shaped cross section; and a plurality of radiating fins that are disposed so as to stand on at least one of an inner circumferential wall surface or an outer circumferential wall surface of said heatsink base, and that extend axially, said two heatsinks being disposed approximately concentrically relative to a central axis of said shaft so as to line up radially; and a plurality of rectifying parts that are mounted onto the inner circumferential wall surface or the outer circumferential wall surface of said heatsink bases so as to be spaced apart from each other circumferentially, wherein said heatsink bases are prepared by bending and shaping into an arc shape a flat plate-shaped base member onto which said plurality of rectifying parts have been mounted. 2. An automotive alternator according to Claim 1, characterized in that said rectifying parts are crimped and fixed by fixing hooks that are disposed so as to stand on said heatsink bases near two circumferential sides of said rectifying parts. 3. An automotive alternator according to Claim 2, characterized in that said rectifying parts are mounted to the inner circumferential wall surface of said heatsink bases, and are crimped and fixed by said fixing hooks during bending and shaping of said heatsink bases. 4. An automotive alternator according to any one of Claims 1 through 3, characterized in that said radiating fins are disposed so as to stand on the inner circumferential wall surface and the outer circumferential wall surface of at least one heatsink base of said heatsink bases. 5. An automotive alternator according to any one of Claims 1 through 4, characterized in that a bending facilitating portion that is configured by reducing a wall thickness of said heatsink bases is formed on a portion of said heatsink bases between said rectifying parts. 6. An automotive alternator according to any one of Claims 1 through 5, characterized in that said rectifying parts comprise an axial movement restricting portion that restricts axial movement of said rectifying parts by engaging with two width direction side surfaces of said heatsink base. 7. An automotive alternator according to any one of Claims 1 through 6, characterized in that: an air intake aperture is disposed through said case so as to face axially to said heatsinks; and a cooling airflow guiding portion is formed on a first axial end portion of at least one of said heatsink bases or said rectifying parts such that a cooling airflow that is sucked in through said air intake aperture due to rotation of said fan that is fixed to said rotor is led between said radiating fins. 8. An automotive alternator rectifying apparatus manufacturing method for a rectifying apparatus comprising^ two heatsinks that each have: a heatsink base that has been prepared so as to have a tubular body that has an arc-shaped cross section; and a plurality of radiating fins that are disposed so as to stand on at least one of an inner circumferential wall surface and an outer circumferential wall surface of said heatsink base, and that extend axially, said two heatsinks being disposed approximately concentrically so as to line up radially; and a plurality of rectifying parts that are mounted onto an inner circumferential wall surface or an outer circumferential wall surface of said heatsink bases so as to be spaced apart from each other circumferentially, said automotive alternator rectifying apparatus manufacturing method being characterized in comprising steps of preparing a heatsink parent material that has: a flat plate-shaped base member that has a predetermined length; and a plurality of radiating fins that are disposed so as to stand on at least one surface of said base member; mounting said rectifying parts on top of a first surface of said base member; and forming said heatsink by bending said base member onto which said rectifying parts have been mounted into an arc shape. 9. An automotive alternator rectifying apparatus manufacturing method according to Claim 8, characterized in that: in said step of preparing said heatsink parent material, positioning recessed grooves are recessed into a region of said first surface of said base member onto which said rectifying parts are mounted; and in said step of mounting said rectifying parts, said rectifying parts ' are mounted onto said first surface of said base member by being placed inside said positioning recessed grooves, said rectifying parts being positioned while restricting longitudinal movement. 10. An automotive alternator rectifying apparatus manufacturing method according to either of Claims 8 or 9, characterized in that: in said step of preparing said heatsink parent material, fixing hooks are disposed so as to stand upright on two longitudinal sides of a region of said first surface of said base member onto which said rectifying parts are mounted; and in said step of forming said heatsink, said rectifying parts are crimped and fixed by said fixing hooks by bending said base member into an arc shape such that said first surface of said base member is placed on a radially inner side. 11. An automotive alternator rectifying apparatus manufacturing method according to Claim 8, characterized in that: in said step of preparing said heatsink parent material, positioning projections are disposed so as to stand upright on two longitudinal sides of a region of said first surface of said base member onto which said rectifying parts are mounted; and in said step of mounting said rectifying parts, said rectifying parts are mounted onto said first surface of said base member by being placed between said positioning projections, said rectifying parts being positioned while restricting longitudinal movement. 12. An automotive alternator rectifying apparatus manufacturing method according to any one of Claims 8 through 11, characterized in that in said step of preparing said heatsink parent material, a bending facilitating portion is formed in which a wall thickness of said base member is reduced for a predetermined length in a longitudinal direction and over an entire region in a width direction between regions onto which said rectifying parts are mounted. 13. An automotive alternator rectifying apparatus manufacturing method according to any one of Claims 8 through 12, characterized in that said rectifying parts have a pair of axial movement restricting portions, and said pair of axial movement restricting portions extend outward at two width direction sides of said base member and engage with two width direction side surfaces of said base member such that movement of said rectifying parts in a width direction of said base member is restricted when said rectifying parts are mounted to said first surface of said base member. 14. An automotive alternator rectifying apparatus manufacturing method according to any one of Claims 8 through 13, characterized in comprising a step of soldering said rectifying parts to said first surface of said base member prior to said step of forming said heatsink.

Full Text

AUTOMOTIVE ALTERNATOR AND METHOD FOR MANUFACTURING A RECTIFYING APPARATUS MOUNTED THERETO
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an automotive alternator and a method for manufacturing a rectifying apparatus that can be mounted thereto, and particularly relates to a rectifying apparatus heatsink construction.
2. Description of the Related Art
In first conventional rectifying apparatuses that can be mounted to an automotive alternator, a radiator that is configured into a single part that is formed by linking two arms into a V shape, and that has fixing lugs at respective end portions of the V shape thereof is fixed to a rear bearing by screws or tie rods that are passed through the respective fixing lugs, and is disposed inside a case of the automotive alternator. The arms between the fixing lugs each have^ a base; a plurality of radiating fins that are disposed so as to line up in a longitudinal direction of the base such that each projects radially inward from the base and extends axially; and a wall that projects radially outward from a flat back surface that is parallel to an axial direction radially outside the base, and that extends in a direction that is perpendicular to an axial direction, and diodes are brazed onto a surface of the wall that is perpendicular to the axial direction (See Figure 9 of Patent Literature 1, for example).
In second conventional rectifying apparatuses that can be mounted to an automotive alternator, two radiators that each have fixing lugs at two ends are fixed to a rear bearing by screws or tie rods that are passed through a pair of stacked fixing lugs and two remaining fixing lugs, and are

disposed inside a case of the automotive alternator in a V shape. The radiators each have: a base; and a plurality of radiating fins that are disposed so as to line up in a longitudinal direction of the base such that each projects radially inward from the base and extends axially, and diodes are brazed onto a flat surface that is parallel to an axial direction radially outside the base (See Figures 3 and 4 of Patent Literature 1, for example). Patent Literature i: Japanese Patent No. 4187647 (Gazette) In the first conventional rectifying apparatuses, because the radiator is disposed inside the case of the automotive alternator so as to position the shaft inside the V shape, outside diameter dimensions of the radiator are restricted by inside diameter dimensions of the case. Because the wall for mounting the diodes projects radially outward from the flat surface that is parallel to an axial direction radially outside the base, the radial position of the base must be offset radially inward by an amount proportionate to protrusion of the wall. Thus, one problem has been that radial height of the radiating fins is reduced, reducing heat radiating area and lowering cooling capacity of the radiator.
In the second conventional rectifying apparatuses, on the other hand, because the diodes are mounted to flat surfaces that are parallel to an axial direction radially outside the base, the base can be offset radially outward compared to the first conventional rectifying apparatuses. Thus, radial height of the radiating fins can be increased, increasing heat radiating area and raising cooling capacity of the radiator. However, because the second conventional rectifying apparatuses are configured so as to be divided into two radiators, one problem has been that the number of parts is increased, reducing ease of assembly.
SUMMARY OF THE INVENTION
The present invention aims to solve the above problems and an

object of the present invention is to provide an automotive alternator and a method for manufacturing a rectifying apparatus that can be mounted thereto that can expand heat radiating area by using installation space inside a case efficiently, and that can be assembled easily without parts being increased in number.
In order to achieve the above object, according to one aspect of the present invention, there is provided an automotive alternator including: a case; a rotor that is disposed inside the case so as to be fixed to a shaft that is rotatably supported by the case; a stator that is disposed so as to be supported by the case so as to cover an outer circumference of the rotor, and that is formed by mounting a stator coil to a stator core; a rectifying apparatus that is disposed at a first axial direction side of the rotor inside the case, and that is electrically connected to the stator coil so as to rectify alternating current that is generated in the stator coil into direct current; and a fan that is fixed to an end surface of the rotor at the first axial end. The rectifying apparatus includes^ two heatsinks that each have: a heatsink base that has been prepared so as to have a tubular body that has an arc-shaped cross section; and a plurality of radiating fins that are disposed so as to stand on at least one of an inner circumferential wall surface or an outer circumferential wall surface of the heatsink base, and that extend axially, the two heatsinks being disposed approximately concentrically relative to a central axis of the shaft so as to line up radially; and a plurality of rectifying parts that are mounted onto the inner circumferential wall surface or the outer circumferential wall surface of the heatsink bases so as to be spaced apart from each other circumferentially. Further, the heatsink bases are prepared by bending and shaping into an arc shape a flat plate-shaped base member onto which the plurality of rectifying parts have been mounted.
According to the present invention, a heatsink base is prepared by

bending and shaping a flat plate-shaped base member into an arc shape. Thus, a tubular heatsink base that has an arc-shaped cross section that can increase the heat radiating area can be prepared easily without having to use processing methods that have inferior yield such as extrusion, or milling, etc. The heatsink can be prepared as a single part, suppressing increases in the number of parts.
Because a flat plate-shaped base member onto which the rectifying parts have been mounted is bent and shaped, mounting of the rectifying parts onto the base member need only be performed in a direction that is perpendicular to the front surface of the base member, facilitating assembly of the rectifying apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a longitudinal section of an automotive alternator according to Embodiment 1 of the present invention;
Figure 2 is a side elevation of a rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention;
Figure 3A is a side elevation that explains a configuration of a diode that can be used in the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention;
Figure 3B is a plan that explains the configuration of the diode that can be used in the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention;
Figure 4A is a process diagram that explains a method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention;
Figure 4B is a process diagram that explains the method for manufacturing the rectifying apparatus that can be mounted to the

automotive alternator according to Embodiment 1 of the present invention,"
Figure 4C is a process diagram that explains the method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention,'
Figure 5A is a process diagram that explains the method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention;
Figure 5B is a process diagram that explains the method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention;
Figure 5C is a process diagram that explains the method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention;
Figure 5D is a process diagram that explains the method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention;
Figure 6 is an electrical circuit diagram for the automotive alternator according to Embodiment 1 of the present invention;
Figure 7A is a partial side elevation that explains a method for manufacturing a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 2 of the present invention;
Figure 7B is a partial side elevation that explains the method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 2 of the present invention;
Figure 8 is a side elevation of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 3 of the present invention;
Figure 9 is a side elevation of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator

according to Embodiment 4 of the present invention,*
Figure 10 is a partial side elevation of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 5 of the present invention;
Figure llA is a partial side elevation that explains a method for manufacturing a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 6 of the present invention;
Figure llB is a partial side elevation that explains the method for manufacturing the second heatsink assembly of the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 6 of the present invention;
Figure 12 is a side elevation of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 7 of the present invention,"
Figure 13A is a side elevation that explains a configuration of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 8 of the present invention;
Figure 13B is a cross section that explains the configuration of the second heatsink assembly of the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 8 of the present invention;
Figure 13C is an exploded projection that explains the configuration of the second heatsink assembly of the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 8 of the present invention;
Figure 14 is a partial cross section of a vicinity of a rectifying apparatus that can be mounted to an automotive alternator according to

Embodiment 9 of the present invention,'
Figure 15 is a partial cross section of a vicinity of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 10 of the present invention;
Figure 16A is a side elevation that explains a method for manufacturing a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 11 of the present invention,' and
Figure 16B is a side elevation that explains the method for manufacturing the second heatsink assembly of the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 11 of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1
Figure 1 is a longitudinal section of an automotive alternator according to Embodiment 1 of the present invention, Figure 2 is a side elevation of a rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention, and Figures 3A and 3B are diagrams that explain a configuration of a diode that can be used in the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention, Figure 3A being a side elevation and Figure 3B being a plan. Figures 4A through 4C are process diagrams that explain a method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention, Figures 5A through 5D are process diagrams that explain the method for manufacturing the rectifying apparatus that can be mounted to the automotive alternator according to Embodiment 1 of the present invention, and Figure 6 is an

electrical circuit diagram for the automotive alternator according to Embodiment 1 of the present invention.
In Figure 1, an automotive alternator 100 includes: a case 1 that is constituted by a front bracket 2 and a rear bracket 3 that are each made of aluminum so as to have an approximate cup shape; a rotor 15 that is rotatably disposed inside the case 1 such that a shaft 18 is supported by means of bearings 4 in the case i; a pulley 5 that is fixed to an end portion of the shaft 18 that projects outward at a front end of the case i; fans 6 that are fixed to two axial end surfaces of the rotor 15; a stator 12 that is fixed to the case 1 so as to surround an outer circumference of the rotor 15 so as to have a constant air gap relative to the rotor 15; a pair of slip rings 7 that are fixed to a rear end of the shaft 18, and that supply current to the rotor 15; a pair of brushes 8 that slide on surfaces of the respective slip rings 7; a brush holder 9 that accommodates the brushes 8; a rectifying apparatus 20 that is electrically connected to the stator 12 so as to convert alternating current that is generated by the stator 12 into the direct current; and a voltage regulator 11 that is mounted onto heatsink 10 that is fitted onto the brush holder 9, and that adjusts magnitude of an alternating-current voltage that is generated by the stator 12.
The stator 12 includes'- a cylindrical stator core 13; and a stator coil 14 that is mounted to the stator core 13, and in which an alternating current arises due to changes in magnetic flux from a field coil 16 that accompany rotation of the rotor 15.
The rotor 15 includes: a field coil 16 that generates magnetic flux on passage of an excitation current; a pole core 17 that is disposed so as to cover the field coil 16 and in which magnetic poles are formed by that magnetic flux; and the shaft 18, which is fitted through a central axial position of the pole core 17. The fans 6 are fixed to the two axial end surfaces of the pole core 17 by welding, etc.

Next, a configuration of the rectifying apparatus 20 will be explained.
As shown in Figures 1 and 2, the rectifying apparatus 20 includes: positive-side diodes 21 that function as rectifying parts," negative-side diodes 22 that function as rectifying parts; a first heatsink 27 that supports the positive-side diodes 2i; a second heatsink 33 that supports the negative-side diodes 22; and a circuit board 40 that electrically connects the positive-side and negative-side diodes 21 and 22 and the stator coil 14.
As shown in Figure 3, the positive-side diodes 21 include: a rectifying element 23 that is configured by forming an n-type semiconductor and a p-type semiconductor into a p-n junction; a copper base 24 that is soldered to a surface of the n-type semiconductor of the rectifying element 23 on an opposite side from the p-type semiconductor; an insulating resin portion 25 that is formed into an approximate parallelepiped by molding the rectifying element 23 and the copper base 24; and a lead terminal 26a of which a first end is connected to the p-type semiconductor of the rectifying element 23 and is extended outward from the insulating resin portion 25, and of which a second end is connected to the circuit board 40. Similarly, the negative-side diodes 22 include-' a rectifying element 23; a copper base 24 that is soldered to a surface of the p-type semiconductor of the rectifying element 23 on an opposite side from the n-type semiconductor; an insulating resin portion 25 that is formed into an approximate parallelepiped by molding the rectifying element 23 and the copper base 24; and a lead terminal 26b of which a first end is connected to the n-type semiconductor of the rectifying element 23 and is extended outward from the insulating resin portion 25, and of which a second end is connected to the circuit board 40.
The first heatsink 27 is prepared using a good heat-conducting material such as aluminum or copper, etc., has a predetermined axial

length (width) and a predetermined radial width (wall thickness), and includes-' a first heatsink base 28 that is bent and shaped into a tubular body that has a cross section perpendicular to an axial direction that is a circular arc shape; a plurality of radiating fins 29 that are disposed so as to stand in a radial pattern at a predetermined pitch circumferentially on outer circumferential wall surfaces of the first heatsink base 28, and that each extend axially; and fixing lugs 30 that are disposed so as to extend radially outward from a first axial edge of first and second circumferential end portions and a central portion of the first heatsink base 28 by being bent into L shapes. Apertures 31 for inserting fixing members such as mounting bolts, etc., are disposed through the fixing lugs 30.
In addition, positioning projections 32 project to a predetermined height and extend axially on inner circumferential wall surfaces of the first heatsink base 28 between each of the fixing lugs 30 on two circumferential sides of mounting regions of three positive-side diodes that are disposed so as to have a predetermined spacing circumferentially (hereinafter "diode mounting surfaces"). The positive-side diodes 21 are positioned by the positioning projections 32 so as to be placed on each of the diode mounting surfaces, and are mounted by soldering the copper bases 24.
The second heatsink 33 is prepared using a good heat-conducting material such as aluminum or copper, etc., has a predetermined axial length (width) and a predetermined radial width (wall thickness), and includes; a second heatsink base 34 that is bent and shaped into a tubular body that has a cross section perpendicular to an axial direction that is a circular arc shape; a plurality of radiating fins 35 that are disposed so as to stand in a radial pattern at a predetermined pitch circumferentially on outer circumferential wall surfaces of the second heatsink base 34, and that each extend axially; and fixing lugs 36 that are formed on first and second circumferential end portions and a central portion of the second
heatsink base 34. Apertures 37 for inserting fixing members such as mounting bolts, etc., are disposed through the fixing lugs 36. The second heatsink base 34 is prepared so as to have an inside diameter that is larger than an outside diameter of the circular arc that is constituted by the projecting ends of the radiating fins 29 that are disposed so as to stand in a radial pattern on the outer circumferential wall surfaces of the first heatsink base 28.
In addition, positioning projections 38 project to a predetermined height and extend axially on inner circumferential wall surfaces of the second heatsink base 34 between each of the fixing lugs 36 on two circumferential sides of mounting regions of three negative-side diodes that are disposed so as to have a predetermined spacing circumferentially (hereinafter "diode mounting surfaces"). The negative-side diodes 22 are positioned by the positioning projections 38 so as to be placed on each of the diode mounting surfaces, and are mounted by soldering the copper bases 24.
As shown in Figure 2, first and second heatsinks 27 and 33 that have been prepared in this manner are disposed concentrically by placing the fixing lugs 36 and 30 on top of each other with insulating tubes 39 interposed. The first and second heatsinks 27 and 33 are mounted to the case 1 with the circuit board 40 stacked thereon by passing mounting bolts (not shown) through the circuit board 40 and the apertures 31 and 37 and fastening the mounting bolts to an inner wall surface of the rear bracket 3. Here, the first and second heatsinks 27 and 33 are disposed so as to be approximately concentric with a central axis of the shaft 18. The second heatsink 33 is mounted to the inner wall surface of the rear bracket 3 so as to ensure a state of thermal contact, and in a state of electrical connection, and is grounded. The first heatsink 27 is mounted in a state of electrical insulation from the second heatsink 33 and the rear bracket 3. Moreover,

the brush holder 9 is disposed between the first and second circumferential end portions of the circular arc-shaped first and second heatsinks 27 and 33.
Here, the circuit board 40 is a resin-molded body into which a plurality of inserted conductors are insert-molded, and end portions of the inserted conductors are exposed to constitute connecting terminals. The lead terminals 26a and 26b of the positive-side and negative-side diodes 21 and 22 are connected to the connecting terminals of the circuit board 40, and output wires 41 of windings 14a through 14f that constitute the stator coil 14 are also connected to the connecting terminals of the circuit board 40.
Thus, as shown in Figure 6, the rectifying apparatus 20 is constituted by first and second rectifying apparatuses 20A and 20B that are constituted by diode bridges formed by three diode pairs that are made by connecting the positive-side diodes 21 and the negative-side diodes 22 in series.
As shown in Figure 6, the stator coil 14 is constituted by a three-phase alternating-current winding 14A that is formed by wye-connecting three windings 14a, 14b, and 14c, and a three-phase alternating-current winding 14B that is formed by wye-connecting three windings 14d, 14e, and 14f, and the respective output ends of each of the windings 14a, 14b, 14c, 14d, 14e, and 14f are connected to connection points between the positive-side diodes 21 and the negative-side diodes 22 of the respective diode pairs. Thus, three-phase alternating-current voltages that are output from the respective output ends of the three-phase alternating-current winding 14A are output so as to be full-wave rectified by the first rectifying apparatus 20A, and three-phase alternating-current voltages that are output from the respective output ends of the three-phase alternating-current winding 14B are output so as to be full-wave rectified

by the second rectifying apparatus 20B.
Next, action of an automotive alternator 100 that has been configured in this manner will be explained.
First, current is supplied from a battery (not shown) to the field coil 16 of the rotor 15 by means of the brushes 8 and the slip rings 7, generating magnetic flux. The pole core 17 is magnetized by this magnetic flux into North-seeking (N) poles and South-seeking (S) poles alternately in a circumferential direction.
At the same time, rotational torque from an engine is transmitted to the shaft 18 by means of a belt (not shown) and the pulley 5, rotating the rotor 15. Thus, rotating magnetic fields are applied to the stator coil 14 of the stator 12, generating electromotive forces in the stator coil 14. These alternating-current electromotive forces are rectified into direct current by the rectifying apparatus 20, then charged to the battery, or supplied to an electric load, etc.
Here, the fans 6 are driven to rotate due to the rotation of the rotor 15, and cooling airflows are sucked inside the rear bracket 3 through air intake apertures 3a that are disposed through an end surface of the rear bracket 3. Cooling airflows that have been sucked into the rear bracket 3 flow through axially between the radiating fins 29 and 35 and reach the rotor 15. A cooling airflow that has been sucked into the rear bracket 3 also flows radially inward along the heatsink 10, and subsequently flows axially and reaches the rotor 15. The cooling airflows that have flowed to the rotor 15 are deflected centrifugally by the fans 6, and are discharged outside the rear bracket 3 through air discharge apertures 3b that are disposed through side surfaces of the rear bracket 3. Moreover, at the front end cooling airflows are also sucked in through air intake apertures 2a that are disposed through an end surface of the front bracket 2, are deflected centrifugally by the fans 6, and are discharged outside the front

bracket 2 through air discharge apertures 2b that are disposed through side surfaces of the front bracket 2.
Thus, heat that is generated in the voltage regulator 11 is radiated to the cooling airflow that flows along the heatsink 10. Heat that is generated in the positive-side and negative-side diodes 21 and 22 of the rectifying apparatus 20 is radiated to the cooling airflows that flow through between the radiating fins 29 and 35 of the first and second heatsinks 27 and 33. Heat that is generated in the stator coil 14 is radiated from front-end and rear-end coil ends to the cooling airflows that have been deflected centrifugally by the fans 6. Thus, heat-generating parts that are mounted internally inside the case 1 such as the voltage regulator 11, the stator coil 14, and the rectifying apparatus 20, etc., are cooled, suppressing excessive temperature increases, thereby suppressing deterioration of power generating performance and enabling service life of parts to be extended.
According to Embodiment 1, a first heatsink 27 that includes: a first heatsink base 28 that is bent and shaped into a tubular body that has a circular arc-shaped cross section; and a plurality of radiating fins 29 that are disposed so as to stand in a radial pattern on outer circumferential wall surfaces of the first heatsink base 28, and a second heatsink 33 that includes•" a second heatsink base 34 that is bent and shaped into a tubular body that has a circular arc-shaped cross section; and a plurality of radiating fins 35 that are disposed so as to stand in a radial pattern on outer circumferential wall surfaces of the second heatsink base 34, are disposed concentrically, positive-side diodes 21 are mounted to inner circumferential wall surfaces of the first heatsink base 28, and negative-side diodes 22 are mounted to inner circumferential wall surfaces of the second heatsink base 34.
Thus, radial width increases in the first and second heatsink bases 28 and 34 are eliminated, enabling radial height of the radiating fins 29 and 35 to be increased. Heat radiating area is thereby increased, enabling cooling capacity of the first and second heatsinks 27 and 33 to be increased, thereby enabling excessive temperature increases in the positive-side and negative-side diodes 21 and 22 to be suppressed.
Because the first and second heatsinks 27 and 33 are each constituted by a single member, the number of parts can be reduced, enabling the rectifying apparatus 20 to be assembled easily.
Pairs of positioning projections 32 and 38 are disposed so as to extend axially on two circumferential sides of respective diode mounting surfaces on inner circumferential wall surfaces of the first and second heatsink bases 28 and 34 so as to project to a predetermined projecting height. Thus, because positioning of the positive-side and negative-side diodes 21 and 22 is performed by using the pairs of positioning projections 32 and 38 as guides to place the positive-side and negative-side diodes 21 and 22 on each of the diode mounting surfaces of the inner circumferential wall surfaces of the first and second heatsink bases 28 and 34, ease of assembly of the rectifying apparatus 20 is improved.
Next, a method for manufacturing the rectifying apparatus 20 will be explained with reference to Figures 4 and 5.
First, a second heatsink parent material 55 that is shown in Figure 4A is prepared. The second heatsink parent material 55 includes: a second base member 56 that is prepared so as to have a flat plate shape that has a rectangular cross section that has a predetermined width and a predetermined thickness, and on which fixing lugs 36 are formed at two longitudinal end portions and a central portion; and a plurality of radiating fins 57 that are disposed so as to stand on flat rear surfaces of the second base member 56 so as to be perpendicular and to extend in a width direction, and that are arranged at a predetermined pitch in a longitudinal direction. In addition, three pairs of positioning projections 38 that have a predetermined spacing in the longitudinal direction and that extend in the width direction so as to project to a predetermined height are disposed on respective flat front surfaces of the second base member 56 at a predetermined pitch in the longitudinal direction between each of the fixing lugs 36.
Next, as shown in Figure 4B, the negative-side diodes 22 are placed between the respective pairs of positioning projections 38 (onto the diode mounting surfaces) from above the flat front surfaces of the second base member 56. Then, the negative-side diodes 22 are mounted by soldering the copper bases 24 to the front surfaces of the second base member 56.
Next, the second base member 56 is bent into a circular arc shape such that the front surfaces of the second base member 56 are on a radially inner side to obtain a second heatsink assembly in which the negative-side diodes 22 are mounted to the second heatsink 33, as shown in Figure 4C.
Next, a first heatsink parent material 50 that is shown in Figure 5A is prepared. The first heatsink parent material 50 includes^ a first base member 51 that is prepared so as to have a flat plate shape that has a rectangular cross section that has a predetermined width and a predetermined thickness, and on which fixing lugs 30 are formed at two longitudinal end portions and a central portion? and a plurality of radiating fins 52 that are disposed so as to stand on flat rear surfaces of the first base member 51 so as to be perpendicular and to extend in a width direction, and that are arranged at a predetermined pitch in a longitudinal direction. In addition, three pairs of positioning projections 32 that have a predetermined spacing in the longitudinal direction and that extend in the width direction so as to project to a predetermined height are disposed on respective flat front surfaces of the first base member 51 at a predetermined pitch in the longitudinal direction between each of the fixing lugs 30. The fixing lugs 30 extend from two longitudinal end portions and a central portion of the first base member 51 to one width direction side parallel to the front surfaces of the first base member 51.
Next, as shown in Figure 5B, the positive-side diodes 21 are placed between the respective pairs of positioning projections 32 (onto the diode mounting surfaces) from above the flat front surfaces of the first base member 51. Then, the positive-side diodes 21 are mounted by soldering the copper bases 24 to the front surfaces of the first base member 51.
Next, as shown in Figure 5C, each of the fixing lugs 30 is bent toward the rear surface side of the first base member 51 into an L shape.
Next, the first base member 51 is bent into a circular arc shape such that the front surfaces of the first base member 51 are on a radially inner side to obtain a first heatsink assembly in which the positive-side diodes 21 are mounted to the first heatsink 27, as shown in Figure 5D.
Next, as shown in Figure 2, the first heatsink 27 and the second heatsink 33 are disposed concentrically such that the fixing lugs 30 are stacked on the fixing lugs 36 with insulating tubes 39 interposed. Finally, the rectifying apparatus 20 is installed in the case 1 by stacking the circuit board 40 on top of the first and second heatsinks 27 and 33, passing mounting bolts through the circuit board 40 and the apertures 31 and 37 of the fixing lugs 30 and 36, and fastening the mounting bolts to the inner wall surface of the rear bracket 3.
Now, conventionally, first and second heatsinks that include"• first and second heatsink bases that have tube bodies that have circular arc-shaped cross sections! and a plurality of radiating fins that are disposed so as to stand in a radial pattern on outer circumferential wall surfaces of the first and second heatsink bases are prepared using processing methods such as extrusion, or milling, etc., and yield has been poor.

However, according to the manufacturing method according to Embodiment 1, because the first and second heatsinks 27 and 33 are prepared by preparing first and second heatsink parent materials 50 and 55 that have flat first and second base members 51 and 56 that have a rectangular cross section, and then bending the first and second heatsink parent materials 50 and 55 into circular arc shapes, yield can be improved significantly.
According to the manufacturing method according to Embodiment 1, because the first and second heatsink parent materials 50 and 55 are bent into circular arc shapes such that the radiating fins 52 and 57 are oriented radially outward, the radiating fins 52 and 57 can be separated and shaped into a radial pattern, enabling cooling of the first and second heatsinks 27 and 33 to be improved.
Conventionally, when diodes are mounted onto first and second heatsinks that have been prepared using processing methods such as extrusion, or milling, etc., the diodes must be mounted onto each of the diode mounting surfaces on the inner circumferential wall surfaces of the first and second heatsink bases of the circular arc-shaped tubular body from a radial direction while moving circumferentially, making the process of mounting the diodes extremely complicated.
However, according to the manufacturing method according to Embodiment 1, the positive-side and negative-side diodes 21 and 22 are mounted to the first and second base members 51 and 56 before bending the first and second heatsink parent materials 50 and 55 into circular arc shapes. Thus, mounting of the positive-side and negative-side diodes 21 and 22 need be performed only in a direction that is perpendicular to the flat front surfaces of the first and second base members 51 and 56, significantly simplifying the process of mounting the positive-side and negative-side diodes 21 and 22.

In Embodiment 1 above, fixing lugs 30 that extend from the first base member 51 parallel to the front surfaces of the first base member 51 to one width direction side are formed simultaneously during preparation of the first heatsink parent material 50, but the fixing lugs 30 may also be formed so as to be bent toward the rear surface side of the first base member 51 into L shapes simultaneously during preparation of the first heatsink parent material 50. In that case, a step of bending the fixing lugs 30 into L shapes is eliminated, simplifying steps for manufacturing the first heatsink 27.
Embodiment 2
Figures 7A and 7B are partial side elevations that explain a method for manufacturing a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 2 of the present invention, Figure 7A showing a state in which a negative-side diode is placed and Figure 7B showing a state in which the negative-side diode is fixed.
As shown in Figure 7A, in a second heatsink parent material 55A according to Embodiment 2, fixing hooks 42 are disposed so as to extend in a width direction on front surfaces of a second base member 56 on two longitudinal sides of the diode mounting surfaces in a longitudinal direction so as to project to a predetermined height. Moreover, the second heatsink parent material 55A is prepared in a similar manner to the second heatsink parent material 55 except for the fact that the fixing hooks 42 are disposed instead of the positioning projections 38.
As shown in Figure 7B, when the second heatsink parent material 55A onto the second base member 56 of which the negative-side diodes 22 are mounted is bent into an circular arc shape, the fixing hooks 42 lean inward toward the copper bases 24 of the negative-side diodes 22 from the two longitudinal sides such that the negative-side diodes 22 are crimped

and fixed to the second heatsink base 34 that is bent and shaped into a circular arc shape. Thus, a second heatsink assembly is obtained in which the negative-side diodes 22 are mounted to the second heatsink 33A.
According to Embodiment 2, because the negative-side diodes 22 are crimped and fixed by the fixing hooks 42 in the step of bending the second heatsink parent material 55A, need for a soldering step is eliminated, simplifying the step of manufacturing the second heatsink proportionately.
Now, fixing hooks are formed on a first base member in a similar manner in a first heatsink parent material, and positive-side diodes are also mounted to the first heatsink so as to be crimped and fixed by the fixing hooks by performing a step of bending the first heatsink parent material.
Moreover, in Embodiment 2 above, the negative-side diodes 22 are placed on the diode mounting surfaces of the second base member 56, and the second heatsink parent material 55A is subsequently bent into a circular arc shape so as to crimp and fix the negative-side diodes 22 to the second heatsink base 34, but the negative-side diodes 22 may also be placed on the diode mounting surfaces of the second base member 56 and crimped and fixed by bending the fixing hooks 42 toward the negative-side diodes 22, and then the second heatsink parent material 55A subsequently bent into a circular arc shape. In that case, because the second heatsink parent material 55A can be bent with the negative-side diodes 22 in a fixed state, the negative-side diodes 22 will not fall out in the bending step, enabling the second heatsink parent material 55Ato be bent simply and stably.
In Embodiment 2 above, the negative-side diodes 22 are placed on the diode mounting surfaces of the second base member 56, and the second heatsink parent material 55A is subsequently bent into a circular arc shape so as to crimp and fix the negative-side diodes 22 to the second heatsink

base 34, but the negative-side diodes 22 may also be placed on the diode mounting surfaces of the second base member 56 and the copper bases 24 soldered, and then the second heatsink parent material 55A subsequently bent into a circular arc shape. In that case, because the second heatsink parent material 55A can be bent with the negative-side diodes 22 in a fixed state, the negative-side diodes 22 will not fall out in the bending step, enabling the second heatsink parent material 55A to be bent simply and stably. In addition, because the negative-side diodes 22 are fixed to the second heatsink base 34 by soldering and crimping, the negative-side diodes 22 are held on the second heatsink base 34 very strongly.
Embodiment 3
Figure 8 is a side elevation of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 3 of the present invention.
In Figure 8, fixing lugs 36 are formed at four positions on a second heatsink base 34 that is bent and shaped into a tubular body that has a circular arc-shaped cross section, including two circumferential end portions and portions that divide the second heatsink base 34 into three sections circumferentially. Radiating fins 35 are disposed so as to stand in a radial pattern on outer circumferential wall surfaces of the second heatsink base 34. In addition, a second heatsink 33B is prepared by disposing two negative-side diodes 22 on respective inner circumferential wall surfaces of the second heatsink base 34 between each of the fixing lugs 36, and mounting them by soldering the copper bases 24. Because a first heatsink is also prepared in a similar manner, explanation thereof will be omitted here.
Moreover, the rest of the configuration is configured in a similar manner to Embodiment 1 above.

According to Embodiment 3, because distances between the fixing lugs 36 are shorter, the operation of bending the heatsink parent material into a circular arc shape is facilitated, and bending stress is also reduced, improving reliability of the second heatsink 33B.
Embodiment 4
Figure 9 is a side elevation of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 4 of the present invention.
In Figure 9, fixing lugs 36 are formed at three positions on a second heatsink base 34 that is bent and shaped into a tubular body that has a circular arc-shaped cross section, including two circumferential end portions and a central portion. Radiating fins 35 are disposed so as to stand in a radial pattern on portions between diode mounting surfaces on inner circumferential wall surfaces of the second heatsink base 34. In addition, a second heatsink 33C is prepared by disposing negative-side diodes 22 on the respective diode mounting surfaces on the inner circumferential wall surfaces of the second heatsink base 34 between each of the fixing lugs 36, and mounting them by soldering the copper bases 24. Because a first heatsink is also prepared in a similar manner, explanation thereof will be omitted here.
Moreover, the rest of the configuration is configured in a similar manner to Embodiment 1 above.
Because a first heatsink and a second heatsink 33C that have been prepared in this manner are disposed inside a rear bracket of an automotive alternator concentrically, radiating fins are disposed in a space on a radially inner side where flow velocity is comparatively high, improving cooling performance of the first and second heatsinks.

Embodiment 5
Figure 10 is a partial side elevation of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 5 of the present invention.
In Figure 10, in addition to radiating fins 35, a second heatsink 33D has auxiliary radiating fins 43 that are disposed on portions between diode mounting surfaces on inner circumferential wall surfaces of a second heatsink base 34 that is bent and shaped into a tubular body that has a circular arc-shaped cross section. Because a first heatsink is also prepared in a similar manner, explanation thereof will be omitted here.
Moreover, the rest of the configuration is configured in a similar manner to Embodiment 1 above.
According to Embodiment 5, because radiating fins 35 are disposed so as to stand on outer circumferential wall surfaces of a second heatsink base 34, and auxiliary radiating fins 43 are disposed so as to stand on inner circumferential wall surfaces of the second heatsink base 34, the heat radiating area of the second heatsink 33D is increased, improving cooling performance of the second heatsink 33D.
Embodiment 6
Figures 11A and llB are partial side elevations that explain a method for manufacturing a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 6 of the present invention. Figure llA showing a state before a step of bending the second heatsink assembly and Figure llB showing a state after the step of bending the second heatsink assembly.
As shown in Figure llA, in a second heatsink parent material 55B according to Embodiment 6, a first recessed groove 44 that functions as a bending facilitating portion is disposed so as to extend in a width direction

on a central portion between diode mounting surfaces on a front surface of a second base member 56 so as to have a groove direction in a width direction. In addition, second recessed grooves 45 that function as a bending facilitating portion are disposed so as to extend in the width direction on rear surfaces of the second base member 56 so as to have a groove direction in the width direction, so as to avoid regions that face the diode mounting surfaces, and so as to be on two sides of a portion that faces the first recessed groove 44. The first and second recessed grooves 44 and 45 are formed for over a entire region in the width direction of the second base member 56.
Negative-side diodes 22 are placed on the diode mounting surfaces on the front surface of the second base member 56, and are mounted to the second heatsink parent material 55B by soldering. Next, the second heatsink parent material 55B is bent into a circular arc shape. As shown in Figure llB, the second base member 56 is then bent at the first recessed grooves 44 and the second recessed grooves 45 to obtain a second heatsink base 34 that is bent and shaped into a tubular body that has an approximately circular arc-shaped cross section. A second heatsink assembly is thereby obtained in which negative-side diodes 22 are mounted to a second heatsink 33E.
According to Embodiment 6, because the second base member 56 is easily bent at the first recessed grooves 44 and the second recessed grooves 45 in the step of bending the second heatsink parent material 55B, bending work is facilitated, and stresses that act on soldered portions in the bending step are reduced, enabling reliability of bonding of the negative-side diodes 22 to the second heatsink base 34 to be improved.
Here, first and second recessed grooves are also formed on a first base member in a first heatsink parent material in a similar manner, facilitating bending of the first heatsink parent material.

Embodiment 7
Figure 12 is a side elevation of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 7 of the present invention.
In Figure 12, a second heatsink base 34 is formed into a tubular body that has an angular C-shaped cross section by being bent at right angles at two bend portions. Fixing lugs 36 are formed at three positions of the second heatsink base 34, including two end portions and a central portion of a floor portion. Radiating fins 35 are disposed so as to stand perpendicular to outer circumferential wall surfaces of the second heatsink base 34. Radiating fins 35 are also formed at the bend portions of the second heatsink base 34 in a radial pattern. In addition, first recessed grooves 44 that have groove directions in a width direction are formed at each of the bend portions of the second heatsink base 34. A second heatsink 33F is prepared by disposing two negative-side diodes 22 on each of respective inner circumferential wall surfaces of the respective sides of the angular C shape of the second heatsink base 34 and mounting them by soldering copper bases 24. Because a first heatsink is also prepared in a similar manner, explanation thereof will be omitted here.
Moreover, the rest of the configuration is configured in a similar manner to Embodiment 1 above.
To prepare a second heatsink 33F that is configured in this manner, a heatsink parent material is first prepared in which first recessed grooves 44 are recessed so as to extend in a width direction at portions that divide a front surface of a second base member 56 such as that shown in Figure 4A into three sections in a longitudinal direction. Next, negative-side diodes 22 are placed on diode mounting surfaces on the front surface of the second base member and soldered. The second base member is sub
at right angles at the first recessed grooves 44 to obtain the second heatsink 33F.
According to Embodiment 7, a second heatsink 33F is bent and shaped into a tubular body that has a cross section that is a polygon that has two corner portions, and a first heatsink is also prepared in a similar manner to the second heatsink 33F. Thus, because the first and second heatsinks can be disposed so as to extend circumferentially inside a space that surrounds the shaft 18 inside the rear bracket 3, heat radiating area can be increased, enabling cooling performance of the first and second heatsinks to be increased in a similar manner to Embodiment 1 above.
Because the first recessed grooves 44 are recessed into the front surface of the second base member at the bend portions, the operation of bending the second heatsink parent material is facilitated, and bending stresses are also reduced, improving the reliability of the second heatsink 33F. Stresses that act on the soldered portions are also reduced in the bending step, enabling reliability of bonding of the negative-side diodes 22 to the second heatsink base 34 to be improved.
Moreover, in Embodiment 7 above, the second heatsink 33F is prepared by bending the second heatsink parent material at right angles at two longitudinal positions, but the bend portions of the second heatsink parent material are not limited to two positions, and may also be at four positions, for example. In that case, first recessed grooves are formed at four positions that divide the second heatsink parent material into five equal sections longitudinally, for example, and portions where each of the first recessed grooves are formed should be bent such that interior angles are 135 degrees.
Embodiment 8
Figures 13A through 13C are diagrams that explain a configuration

of a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 8 of the present invention, Figure ISA being a side elevation that shows a state in which a negative-side diode is fixed, Figure 13B being a cross section that shows the state in which the negative-side diode is fixed, and Figure 13C being an exploded projection of a second heatsink assembly.
In Figure 13, a copper base 24A of a negative-side diode 22A has a length that is longer than a width of the second heatsink base 34, and is formed so as to have an angular C shape in which two end portions project downward. The negative-side diode 22A is mounted to the second heatsink 33A by being placed between a pair of fixing hooks 42 on the second heatsink base 34 such that flange portions 46 of the copper base 24A project toward a rear surface from two ends in a width direction of the second heatsink base 34, and is crimped and fixed by the fixing hooks 42. The flange portions 46 constitute an axial movement restricting portion. Because a first heatsink is also prepared in a similar manner, explanation thereof will be omitted here.
Moreover, the rest of this embodiment is configured in a similar manner to Embodiment 2 above.
According to Embodiment 8, the copper bases 24A of the negative-side diodes 22A are formed so as to have an angular C shape. Thus, when the negative-side diodes 22A are placed on the diode mounting surfaces of the second base member of the second heatsink parent material, movement of the copper bases 24A in the longitudinal direction of the second base member is restricted by the pairs of fixing hooks 42, and movement of the negative-side diodes 22 in the width direction of the second base member is also restricted by the flange portions 46 projecting toward the rear surface from the two width direction sides of the second base member.

Falling out, or dislodgment, etc., of the negative-side diodes 22 thereby is suppressed when conveying the second heatsink parent material on which the negative-side diodes 22 have been placed within a production line, increasing productivity.
Embodiment 9
Figure 14 is a partial cross section of a vicinity of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 9 of the present invention.
In Figure 14, a rear end of a first heatsink base 28 of a first heatsink 27G that is bent and shaped into a tubular body that has a circular arc-shaped cross section projects toward an inner end surface of a rear bracket 3 relative to radiating fins 29. A radial position of an outer circumferential surface of a projecting portion 47 at the rear end of the first heatsink base 28 is formed so as to have a tapered shape that gradually becomes lower toward the rear end. A rear end of a second heatsink base 34 of a second heatsink 33G that is bent and shaped into a tubular body that has a circular arc-shaped cross section projects toward an inner end surface of a rear bracket 3 relative to radiating fins 35. A radial position of an outer circumferential surface of a projecting portion 48 at the rear end of the second heatsink base 34 is formed so as to have a tapered shape that gradually becomes lower toward the rear end. The projecting portions 47 and 48 constitute a cooling airflow guiding portion. Air intake apertures 3a are disposed through the rear bracket 3 so as to face the first and second heatsinks 27G and 33G.
Moreover, the rest of the configuration is configured in a similar manner to Embodiment 1 above.
According to Embodiment 9, air intake apertures 3a are disposed through a rear bracket 3 so as to face first and second heatsinks 27G and

33G, and projecting portions 47 and 48 of first and second heatsink bases 28 and 34 are formed so as to have a tapered shape. Thus, cooling airflows that have been sucked in through the air intake apertures 3a flow along inclined surfaces (outer circumferential wall surfaces) 47a and 48a of the projecting portions 47 and 48 and flow in between the radiating fins 29 and 35. Cooling airflows that have been sucked in through the air intake apertures 3a thereby flow through between the radiating fins 29 and 35 efficiently, improving cooling performance of the first and second heatsinks 27G and 33G.
Embodiment 10
Figure 15 is a partial cross section of a vicinity of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 10 of the present invention.
In Figure 15, copper bases 24B of positive-side and negative-side diodes 2 IB and 22B have a length that is longer than a width of the first and second heatsink bases 28 and 34, and are formed so as to have angular C shapes in which two end portions project radially outward. Radial positions of outer circumferential surfaces of flange portions 49 at the rear ends of the copper bases 24B are formed so as to have tapered shapes that gradually become lower toward the rear end from positions of outer circumferential wall surfaces of the first and second heatsink bases 28 and 34. The flange portions 49 constitute a cooling airflow guiding portion. Air intake apertures 3a are disposed through the rear bracket 3 so as to face first and second heatsinks 27 and 33,
Moreover, the rest of the configuration is configured in a similar manner to Embodiment 1 above.
According to Embodiment 10, air intake apertures 3a are disposed through a rear bracket 3 so as to face first and second heatsinks 27 and 33,

and flange portions 49 of copper bases 24B of positive-side and negative-side diodes 21B and 22B are formed so as to have a tapered shape. Thus, cooling airflows that have been sucked in through the air intake apertures 3a flow along inclined surfaces (outer circumferential wall surfaces) 49a of the flange portions 49 and flow in between the radiating fins 29 and 35. Cooling airflows that have been sucked in through the air intake apertures 3a thereby flow through between the radiating fins 29 and 35 efficiently, improving cooling performance of the first and second heatsinks 27 and 33.
Embodiment 11
Figures 16A and 16B are side elevations that explain a method for manufacturing a second heatsink assembly of a rectifying apparatus that can be mounted to an automotive alternator according to Embodiment 11 of the present invention, Figure 16A showing a state before negative-side diodes are mounted and Figure 16B showing a state after negative-side diodes are mounted.
In Embodiment 11, as shown in Figure 16A, three positioning recessed grooves 58 are recessed at a predetermined pitch in a longitudinal direction on each of respective front surfaces of a second base member 56 of a second heatsink parent material 55C between respective fixing lugs 36. Each of the positioning recessed groove 58 is recessed over an entire region in a width direction of the second base member 56 at a predetermined groove width and at a predetermined depth, and constitutes a diode mounting surface.
As shown in Figure 16B, negative-side diodes 22 are placed inside each of the positioning recessed grooves 58, and are mounted by soldering copper bases 24.
Next, although not shown, the second base member 56 is bent into a

circular arc shape such that the front surfaces of the second base member 56 are on a radially inner side to obtain a second heatsink assembly in which the negative-side diodes 22 are mounted to the second heatsink.
According to Embodiment 11, because the positioning recessed grooves 58 are recessed into the front surfaces of the second base member 56, the negative-side diodes 22 can be positioned while restricting longitudinal movement simply by placing the negative-side diodes 22 inside the positioning recessed grooves 58. Thus, the operation of soldering the negative-side diodes 22 is facilitated.
Here, positioning recessed grooves are also formed on front surfaces of a first base member in a first heatsink parent material in a similar manner, facilitating an operation of soldering positive-side diodes.
Moreover, in each of the above embodiments, positive-side diodes are mounted to a first heatsink that is disposed on a radially inner side and negative-side diodes are mounted to a second heatsink that is disposed on a radially outer side, but positive-side diodes may also be mounted to a second heatsink that is disposed on a radially outer side and negative-side diodes mounted to a first heatsink that is disposed on a radially inner side.
It is not absolutely necessary for axial length of the first and second heatsinks to be equal, and the number of radiating fins, or the fin pitch, etc., may also be set appropriately.
In each of the above embodiments, positive-side diodes and negative-side diodes are mounted to inner circumferential wall surfaces of first and second heatsink bases, but positive-side diodes and negative-side diodes may also be mounted to outer circumferential wall surfaces of first and second heatsink bases, or positive-side diodes may also be mounted to outer circumferential wall surfaces of a first heatsink base and negative-side diodes may be mounted to inner circumferential wall surfaces of a second heatsink, etc.

In each of the above embodiments, three-phase alternating-current windings are explained as being wye-connected, but similar effects are also exhibited if the three-phase alternating-current windings are delta-connected. In each of the above embodiments, six positive-side and six negative-side diodes are mounted onto the respective first and second heatsinks, but the numbers of positive-side and negative-side diodes that are mounted onto the respective first and second heatsinks are not limited to being six. If, for example, the stator coil is constituted by a single three-phase alternating-current winding, and output from the three-phase alternating-current winding is to be full-wave rectified by a diode bridge, then the numbers of positive-side and negative-side diodes that are mounted onto the respective first and second heatsinks will be three. If the stator coil is constituted by a single three-phase alternating-current winding, and output from a wye-connected neutral point is to be full-wave rectified by a diode bridge in addition to the three output ends of the three-phase alternating-current winding, then the numbers of positive-side and negative-side diodes that are mounted onto the respective first and second heatsinks will be four.
In each of the above embodiments, first and second heatsink bases are bent and shaped into tube bodies that have circular arc-shaped cross sections, but the shapes of the first and second heatsink bases are not limited to tube bodies that have circular arc-shaped cross sections, and may be any tubular body that has an arc-shaped cross section that extends circumferentially inside a space inside the case that surrounds the shaft, and that has a predetermined axial length. Moreover, a tubular body that has an angular C-shaped cross section, which is the shape of a heatsink base according to Embodiment 7 above, in other words, a tubular body that has a polygonal cross section that has a plurality of corner portions is also included in the tubular body that has an arc-shaped cross section according to the present application.

WE CLAIM:
1. An automotive alternator comprising:
a case;
a rotor that is disposed inside said case so as to be fixed to a shaft that is rotatably supported by said case!
a stator that is disposed so as to be supported by said case so as to cover an outer circumference of said rotor, and that is formed by mounting a stator coil to a stator core;
a rectifying apparatus that is disposed at a first axial direction side of said rotor inside said case, and that is electrically connected to said stator coil so as to rectify alternating current that is generated in said stator coil into direct current; and
a fan that is fixed to an end surface of said rotor at said first axial end,
said automotive alternator being characterized in that: said rectifying apparatus comprises: two heatsinks that each have:
a heatsink base that has been prepared so as to have a tubular body that has an arc-shaped cross section; and
a plurality of radiating fins that are disposed so as to stand on at least one of an inner circumferential wall surface or an outer circumferential wall surface of said heatsink base, and that extend axially,
said two heatsinks being disposed approximately concentrically relative to a central axis of said shaft so as to line up radially; and
a plurality of rectifying parts that are mounted onto the inner circumferential wall surface or the outer circumferential wall surface of said heatsink bases so as to be spaced apart from
each other circumferentially, wherein said heatsink bases are prepared by bending and shaping into an arc shape a flat plate-shaped base member onto which said plurality of rectifying parts have been mounted.
2. An automotive alternator according to Claim 1, characterized in that said rectifying parts are crimped and fixed by fixing hooks that are disposed so as to stand on said heatsink bases near two circumferential sides of said rectifying parts.
3. An automotive alternator according to Claim 2, characterized in that said rectifying parts are mounted to the inner circumferential wall surface of said heatsink bases, and are crimped and fixed by said fixing hooks during bending and shaping of said heatsink bases.
4. An automotive alternator according to any one of Claims 1 through
3, characterized in that said radiating fins are disposed so as to stand on
the inner circumferential wall surface and the outer circumferential wall
surface of at least one heatsink base of said heatsink bases.
5. An automotive alternator according to any one of Claims 1 through
4, characterized in that a bending facilitating portion that is configured by
reducing a wall thickness of said heatsink bases is formed on a portion of
said heatsink bases between said rectifying parts.
6. An automotive alternator according to any one of Claims 1 through
5, characterized in that said rectifying parts comprise an axial movement
restricting portion that restricts axial movement of said rectifying parts by
engaging with two width direction side surfaces of said heatsink base.

7. An automotive alternator according to any one of Claims 1 through
6, characterized in that:
an air intake aperture is disposed through said case so as to face axially to said heatsinks; and
a cooling airflow guiding portion is formed on a first axial end portion of at least one of said heatsink bases or said rectifying parts such that a cooling airflow that is sucked in through said air intake aperture due to rotation of said fan that is fixed to said rotor is led between said radiating fins.
8. An automotive alternator rectifying apparatus manufacturing
method for a rectifying apparatus comprising^
two heatsinks that each have:
a heatsink base that has been prepared so as to have a tubular body that has an arc-shaped cross section; and a plurality of radiating fins that are disposed so as to stand on at least one of an inner circumferential wall surface and an outer circumferential wall surface of said heatsink base, and that extend axially,
said two heatsinks being disposed approximately concentrically so as to line up radially; and a plurality of rectifying parts that are mounted onto an inner circumferential wall surface or an outer circumferential wall surface of said heatsink bases so as to be spaced apart from each other circumferentially,
said automotive alternator rectifying apparatus manufacturing method being characterized in comprising steps of preparing a heatsink parent material that has: a flat plate-shaped base member that has a predetermined length; and a plurality of radiating fins that are disposed so as to stand on at least one surface of said base member;
mounting said rectifying parts on top of a first surface of said base member; and
forming said heatsink by bending said base member onto which said rectifying parts have been mounted into an arc shape.
9. An automotive alternator rectifying apparatus manufacturing
method according to Claim 8, characterized in that:
in said step of preparing said heatsink parent material, positioning recessed grooves are recessed into a region of said first surface of said base member onto which said rectifying parts are mounted; and
in said step of mounting said rectifying parts, said rectifying parts ' are mounted onto said first surface of said base member by being placed inside said positioning recessed grooves, said rectifying parts being positioned while restricting longitudinal movement.
10. An automotive alternator rectifying apparatus manufacturing method according to either of Claims 8 or 9, characterized in that:
in said step of preparing said heatsink parent material, fixing hooks are disposed so as to stand upright on two longitudinal sides of a region of said first surface of said base member onto which said rectifying parts are mounted; and
in said step of forming said heatsink, said rectifying parts are crimped and fixed by said fixing hooks by bending said base member into an arc shape such that said first surface of said base member is placed on a radially inner side.
11. An automotive alternator rectifying apparatus manufacturing method according to Claim 8, characterized in that:
in said step of preparing said heatsink parent material, positioning projections are disposed so as to stand upright on two longitudinal sides of a region of said first surface of said base member onto which said rectifying parts are mounted; and
in said step of mounting said rectifying parts, said rectifying parts are mounted onto said first surface of said base member by being placed between said positioning projections, said rectifying parts being positioned while restricting longitudinal movement.
12. An automotive alternator rectifying apparatus manufacturing method according to any one of Claims 8 through 11, characterized in that in said step of preparing said heatsink parent material, a bending facilitating portion is formed in which a wall thickness of said base member is reduced for a predetermined length in a longitudinal direction and over an entire region in a width direction between regions onto which said rectifying parts are mounted.
13. An automotive alternator rectifying apparatus manufacturing method according to any one of Claims 8 through 12, characterized in that said rectifying parts have a pair of axial movement restricting portions, and said pair of axial movement restricting portions extend outward at two width direction sides of said base member and engage with two width direction side surfaces of said base member such that movement of said rectifying parts in a width direction of said base member is restricted when said rectifying parts are mounted to said first surface of said base member.
14. An automotive alternator rectifying apparatus manufacturing method according to any one of Claims 8 through 13, characterized in
comprising a step of soldering said rectifying parts to said first surface of said base member prior to said step of forming said heatsink.

Documents:

http://ipindiaonline.gov.in/patentsearch/GrantedSearch/viewdoc.aspx?id=YrA/T0c+1FEO8n1BSzLydw==&loc=egcICQiyoj82NGgGrC5ChA==

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Patent Number

279861

Indian Patent Application Number

377/CHE/2010

PG Journal Number

05/2017

Publication Date

03-Feb-2017

Grant Date

31-Jan-2017

Date of Filing

15-Feb-2010

Name of Patentee

MITSUBISHI ELECTRIC CORPORATION

Applicant Address

7-3, MARUNOUCHI 2- CHOME, CHIYODA-KU, TOKYO 100-8310

Inventors:

#	Inventor's Name	Inventor's Address
1	OONISHI, TOSHIYUKI	C/O CTEC, INC., 6-10-1, ROPPONGI, MINATO-KU, TOKYO 106-6135
2	TANAKA, KAZUNORI	C/O MITSUBISHI ELECTRIC CORPORATION, 7-3, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100-8310

PCT International Classification Number

H02K 9/06

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2009-141458	2009-06-12	Japan