Title of Invention

MAGNET ROTOR AND AC GENERATOR

Abstract

An AC generator (1) comprises a magnet rotor (3) which is fixed to a rotating shaft (2) and a stator (4). The magnet rotor (3) comprises a boss (10) which is fixed by caulking to a center of a yoke (11) in which permanent magnets (12) are fixed, and a rotating shaft (2) is fixed to the boss (10). A socket and spigot type clutch alignment member (22) is formed by forming a recess (20) on a bottom (15) of the yoke (11), and an outer race (31) of a one-way clutch mechanism (30) is aligned and fixed by the socket and spigot type clutch alignment member (22). As a result, the magnet rotor is made smaller and the fabrication of the magnet rotor becomes easy.

Full Text

1 DESCRIPTION MAGNET ROTOR AND AC GENERATOR TECHNICAL FIELD [0001] The present invention relates to an alternating-current generator and a magnet rotor used in an alternating-current generator. Priority is claimed on Japanese Patent Application No. 2005-197376, filed in Japan on July 6, 2005, the contents of which are incorporated herein by reference. BACKGROUND ART [0002] An alternating-current generator (hereinafter called "AC generator") is provided for connecting a magnet rotor to a rotating shaft of a vehicle engine or the like and is used in such applications as transmitting starter motor rotations to the magnet rotor by means of a clutch mechanism thereby rotating a rotating shaft of an engine, converting the rotational energy when rotating to electrical energy in order to recharge batteries, and supplying electric power to auxiliary electrical devices. The conventional magnet rotors provide a structure wherein a boss is connected to a rotating shaft and fixed to a bottom of a cup- shaped yoke. The boss comprises a part protruding from the bottom of the yoke and extending radially to form a flange, and a socket and spigot type clutch alignment member is formed at an outer edge of the flange. The clutch alignment member is formed to align the position of a one-way clutch mechanism, and an outer race of the one-way clutch mechanism is inserted in and engages with an inner circumference of the clutch alignment member, and then the outer race is fixed to the clutch alignment member by bolts (for example refer to Patent Document 1). [Patent Document 1] Japanese Unexamined Patent Application, First Publication No. 2001-251828 2 [0003] However, the conventional magnet rotors required the boss with a larger outer shape to provide the clutch alignment member. As the boss becomes larger, the magnetic rotor becomes larger and the weight increases. Furthermore, rivets and the like are necessary to fix the boss to the yoke thus requiring an increase in the number of parts and an increase of production steps. Still furthermore, since a part of the boss protrudes from the bottom of the yoke, reduction in size of the magnetic rotor along an axial length thereof is prevented. DISCLOSURE OF THE INVENTION In view of such circumstances, it is a primary object of the present invention to reduce the size and increase the ease of production of the AC generator and the magnet rotor. [0004] A first aspect of the present invention that solves the problems recited above provides a magnet rotor comprising a boss connecting with a rotating shaft, and a yoke comprising permanent magnets fixed to a side of a cylindrical part extending from a bottom fixed to the boss, and wherein a socket and spigot type clutch alignment member which engages with a clutch mechanism and aligns the position of the clutch mechanism to the yoke is formed on the yoke. In this magnet rotor, the position of the clutch mechanism is aligned by the clutch alignment member which is formed on a yoke, and the clutch mechanism is directly fixed to the yoke. [0005] A second aspect of the present invention provides a magnet rotor of the first aspect wherein the clutch alignment member is formed on an entire circumference of an outer periphery of the bottom of the yoke. In this magnet rotor, by contacting the clutch alignment member to an entire circumference of an outer edge of the clutch mechanism, the position of the clutch 3 mechanism can be aligned with high precision and the clutch mechanism can be attached to the yoke directly. [0006] A third aspect of the present invention provides the magnet rotor of the first or second aspect, wherein the clutch alignment member is formed on a curved portion which is formed by inwardly bending the bottom of the yoke. In this magnet rotor, by bending the bottom of the yoke at a position matched to the outer diameter of the clutch mechanism, the depth required by the clutch alignment member is secured without decreasing the strength of the bottom. [0007] A fourth aspect of the present invention is an AC generator comprising a magnet rotor according to the first, second or third aspect recited above, a stator in which a coil is wound and is disposed opposite to the permanent magnets. In this AC generator, the clutch mechanism is directly attached to the yoke using the clutch alignment member which is formed on the yoke, and generates inductive electricity in the coil by rotating the permanent magnets together with the rotating shaft. EFFECTS OF THE INVENTION [0008] According to the present invention, since the socket and spigot type clutch alignment member which engages with the clutch mechanism is formed on the yoke, the boss smaller than that of the conventional art in which the clutch alignment member is formed by extending the boss can be obtained easily, and the length of the motor in an axial direction can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS [0009] FIG 1 is a cross-sectional view of an AC generator according to the embodiment of the present invention. 4 FIG. 2 is a cross-sectional view of a yoke and a boss. FIG. 3 is a view in direction A of FIG. 2. FIG. 4 is a cross-sectional view of a yoke after deep drawing. FIG. 5 is a drawing illustrating a process for fixing a boss to a yoke. FIG. 6 is a cross-sectional view of an AC generator. Brief Description of Reference Symbols [0010] 1,50: AC generator 2: Rotating shaft 3,53: Magnet rotor 4: Stator 10: Boss 11: Yoke 12: Permanent magnet 15: Bottom 22,62: Socket and spigot type clutch alignment member 30,70: One-way clutch mechanism (Clutch mechanism) 42: Coil BEST MODE FOR CARRYING OUT THE INVENTION [0011] Herewith, the best mode for carrying out the claimed invention will be described in detail below with reference to the drawings. FIG 1 is a cross-sectional view of an AC generator relating to the first embodiment. The AC generator 1 is an outer rotor-type generator and thus provides a magnet rotor 3 connected to an engine rotating shaft 2 as well as a stator 4 disposed inside a magnet rotor 3 and fixed to an engine case (not shown) or the like. [0012] 5 A magnet rotor 3 comprises a boss 10 mounted on a rotating shaft 2 and a yoke 11 fixed tin which the boss 10 is fixed by caulking, and permanent magnets 12 are fixed on an inner circumference of the yoke 11. The permanent magnets 12 are magnetized to arrange magnetic poles in an alternating fashion circumferentially. The boss 10 comprises a bore 13 in its center, and a distal end portion of the bore 13 provides a tapered bore matched to the shape of the tip of a rotating shaft 2. A proximal end portion of the boss 10 comprises an annular flange 14 extends outward along a radial direction, whereby the annular flange 14 is fixed to the yoke 11 such that the bottom 15 abuts a distal end surface of the flange 14. Furthermore, the boss 10 and the rotating shaft 2 are fixed by a nut 16 so as to coaxially rotate together. [0013] As shown in FIG. 1 through FIG. 3, yoke 11 has a cylindrical shape partially closed by a bottom. Furthermore, a protrusion 17A is protrusionally formed so as to extend outward along the radial direction on a side 17 by pressing to detect the rotational position of the magnet rotor 3 and the rotating shaft 2. The bottom 15 of the yoke 11 is deep drawn to reduce the length in the axial direction of the yoke 11 at an inner circumferential region compared to a circumferential edge. A stepped region 21 of a circumferential edge of a recess 20 on the bottom 15 by deep drawing provides a socket and spigot type clutch alignment member 22 by adjusting an inner circumferential surface 21A to parallel to an axis by milling. Furthermore, a circumferential region inward from the clutch alignment member 22 is deep drawn in a direction to further reduce the length of the bottom 15 in the axial direction, and a bore 24 in which the boss 10 can be inserted is formed in the center of the recess 23 formed herewith. The diameter of the recess 23 of the inner circumferential surface is nearly equal to the outer diameter of the flange 14 of the boss 10, and the thickness of the flange 14 of the boss 10 is nearly equal to the depth of the recess 23. Thereby, the recess 23 receives the flange 14, and the outer surface 20A of recess 20 and the outer surface 14Aof the flange 14 are nearly coplanar. Furthermore, a plurality of bores 25 is opened circumferentially in the recess 23. As 6 shown in FIG. 1, screws 32 are inseited into these bores 25 to fix an outer race 31 of a one- way clutch mechanism 30. [0014] The one-way clutch mechanism 30 supports an inner race 34 in an inner circumferential surface of an annular outer race 31 so as to coaxially rotate the inner race 34 around the axis through bearings 33, and an inner circumferential surface of an inner race 34 is rotatively supported by the rotating shaft 2 through bearings 35. An edge of a proximal end of the inner race 34 extends beyond the outer race 31 and then extends outward along the radial direction. The outer circumference of the enlarged diameter member 34A forms a gear that meshes with a gear of a starter motor which is not shown. [0015] Also, the stator 4 of this AC generator 1 comprises a stator core 40. The stator core 40 is formed by laminating plates of magnetic material in the axial direction and has an inner diameter in which the nut 16 which is screwed on the tip of the rotating shaft 2 can be inserted. Furthermore, the stator core 40 provides a plurality of teeth 40 A which extend outward along a radial direction and arranged circumferentially at regular intervals. Each of the outer circumferences of these teeth 40 A, an insulator 41 is attached and then a coil 42 is wound. The wound coil 42 is electrically connected to a battery or electrical parts (not shown) or the like. [0016] Herewith, effects of this embodiment will be described. When fabricating the AC generator 1, the yoke 11 shaped as a cylindrical part partially closed by a bottom is fabricated by pressing. When forming the bottom 15 of the yoke 11, drawing is performed to simultaneously form recesses 20 and 23, and then a central region is punched to form a bore 24. In this process, as shown in FIG. 4, the stepped region 21 of the recess 20 is formed so as to form a gradual curved surface and to form a taper shape contracting toward the center. Then, the curved surface 2IB formed on the inner circumferential surface of the stepped region 21 is milled annularly and 7 parallel to the axis to form the clutch alignment member 22 on the entire circumference thereof as shown in FIG. 2. This clutch alignment member 22 is made from the curved surface 21B formed by drawing, and thereby secures sufficient height and provides the required strength to interact with the one-way clutch mechanism 30 without increase the thickness of the plate which forms the bottom 15. [0017] Furthermore, as shown in FIG. 5, the boss 10 is inserted in the bore 24, and the flange 14 is abutted to an outer surface of the recess 23. Then, an extremity of the boss 10 is compressed thereby forming a brim 18 as shown in FIG. 2, and the boss 10 is fixed by interposing the circumferential edge of the bore 24 of the yoke 11 between the brim 18 and the flange 14. Afterwards, centering alignment of the outer race 31 is performed to engage the outer race 31 with the inner circumference of the clutch alignment member 22 of the yoke 11, and then the one-way clutch mechanism 30 is fixed to the bottom 15 of the yoke 11 by the screws 32. Then, the permanent magnets 12 are directly fixed to the inner circumference of the side 17 of the yoke 11. Finally, the rotating shaft 2 is inserted in an inner bore of the one-way clutch mechanism 30 and the boss 10, and tapered regions of the rotating shaft 2 and the boss 10 abut each other and then are fixed by the nut 16. [0018] When starting an engine, the rotation of a starter motor is transmitted to the inner race 34 of the one-way clutch mechanism 30. The rotation of the inner race 34 is transmitted to the yoke 11 through the outer race 31, and the boss 10 that is fixed to the yoke 11 rotates the rotating shaft 2. In this way, the engine is started by rotating the rotating shaft 2. Then, upon exceeding a predetermined number of rotations of the rotating shaft 2, the engagement between the outer race 31 of the one-way clutch mechanism 30 that rotates together with the rotating shaft 2 and the inner race 34 is interrupted, and the inner race 34 comes to a halt. Thereby, the starter motor and the engine are separated. Furthermore, as the rotating shaft 2 and the yoke 11 rotate together, the permanent magnets 12 rotate around the stator 4, inductive electricity is induced in each coil 42, and the battery which is not 8 shown is recharged and electrical power is supplied to auxiliary electrical devices. [0019] In accordance with this embodiment, since the clutch alignment member 22 is formed on a yoke 11, enlargement of a boss 10 is avoided, while allowing the alignment of the position and the fixing of the one-way clutch mechanism 30. In prior art, since the clutch alignment member is formed by extending the boss beyond the bottom of the yoke and then extending outward along the radial direction, the boss and the yoke overlap each other in the axial direction, and as a result, a thickness of the AC generator in the axial direction increases. Therefore, the elimination of such overlapping region allows a reduced thickness of the AC generator 1 in the axial direction. Furthermore, the size reduction for the boss 10 provides a weight reduction for the AC generator 1. Moreover, rivets to fix the boss 10 and the yoke 11 can be eliminated. [0020] In addition, since the clutch alignment member 22 is formed on the entire circumference, the position of the one-way clutch mechanism 30 can reliably be aligned. Also, since the clutch alignment member 22 is formed annularly along the entire circumference, the member is easily fabricated, the circularity of the member is easily attained, and the centering of the one-way clutch mechanism 30 can be performed accurately. Furthermore, since the clutch alignment member 22 is formed on the yoke 11 by utilizing the region in which the thickness in the axial direction expands as a result of deep drawing of the bottom 15, the clutch alignment member 22 can be formed without sacrificing strength of the bottom 15. Moreover, it is needless to increase the thickness of the bottom 15 in order to form the clutch alignment member 22, thereby avoiding a weight increase. [0021] Herewith, the second embodiment of the present invention will be described with reference to FIG 6. The same numerals are used for structural elements identical to that of the first embodiment, and repetitive descriptions are omitted. 9 As shown in FIG. 6, an AC generator 50 comprises a magnet rotor 53 and a stator 4. The magnet rotor 53 comprises a boss 10 fixed to a bottom 15 of a yoke 11. An annular protrusion 60 on the periphery of a recess 23 of the bottom 15 is formed by drawing and extends outward in the axial direction, and a socket and spigot type clutch alignment member 62 is formed by utilizing an annular step formed at the outer circumferential side of the protrusion 60. The clutch alignment member 62 comprises an outer circumferential surface 61A which is parallel to the axis by milling on a curved surface on the step formed on the outer circumference. On a circumferential surface of a distal end portion of a one-way clutch mechanism 70 that engages with the clutch alignment member 62, an annular engaging part 72 is formed by concaving a central region of an outer race 71 in the axial direction. [0022] In the case of fabricating the magnet rotor 53, drawing is performed on the bottom 15 of the yoke 11, and the recess 23 and the protrusion 60 are simultaneously formed. Then, the curved surface formed during the formation of the protrusion 60 is milled from an outward along the radial direction to form the annular outer circumferential surface 61 A. The clutch alignment member 62 formed in this way utilizes the curved surface formed by drawing, and thus reliably provides sufficient height arid achieves the required strength to engage with the one-way clutch mechanism 30 without increasing the thickness of the plate which forms the bottom 15. Furthermore, the engaging part 72 of the outer race 71 is engaged with the clutch alignment member 62 from the outside to align the position of the one-way clutch mechanism 70, and then, the one-way clutch mechanism 70 is directly fixed to the yoke 11 by the screws 32. [0023] In accordance with this embodiment, since the clutch alignment member 62 which extends outward along the radial direction is formed on an entire circumference of the bottom 15 of the yoke 11, and since the one-way clutch mechanism 70 is aligned and directly fixed to the yoke 11 by using the clutch alignment member 62, the same effects of 10 the first embodiment are obtained. [0024] The present invention is not restricted to the above described embodiments and wide applications can be allowed. For example, it is possible to use the clutch alignment member 22 without milling after the deep drawing. It is possible to form the clutch alignment member 22 by a method such as milling. Furthermore, the rotating shaft 2 is not limited to the rotating shaft of an engine. The clutch mechanism is not limited to a one-way type. Also, the fixing of the boss 10 and the yoke 11 can be provided by welding. INDUSTRIAL APPLICABILITY [0025] In a magnet rotor comprising a boss engaging a rotating shaft, and a yoke comprising permanent magnets fixed to a side of a cylindrical part extending from a bottom fixed to the boss, a socket and spigot type clutch alignment member which engages with a clutch mechanism and aligns the position of the clutch mechanism to the yoke is formed on the yoke. As a result, since the socket and spigot type clutch alignment member which engages with the clutch mechanism is formed on the yoke, the boss smaller than that of the conventional art in which the clutch alignment member is formed by extending the boss can be obtained easily, and the length of the motor in an axial direction can be reduced. 11 CLAIMS 1. A magnet rotor comprising: a boss connecting with a rotating shaft, and a yoke comprising permanent magnets fixed to a side of a cylindrical part extending from a bottom fixed to said boss; wherein, a socket and spigot type clutch alignment member which engages with a clutch mechanism and aligns the position of said clutch mechanism to said yoke is formed on said yoke, 2. A magnet rotor according to claim 1, wherein said clutch alignment member is formed on an entire circumference of an outer periphery of said bottom of said yoke. 3. A magnet rotor according to claim 1 or 2, wherein said clutch alignment member is formed on a curved portion which is formed by inwardly bending said bottom of said yoke. 4. An AC generator, comprising a magnet rotor according to claim 1 and a stator in which a coil is wound and is disposed opposite to said permanent magnets. 5. An AC generator, comprising a magnet rotor according to claim 2 and a stator in which a coil is wound and is disposed opposite to said permanent magnets. 6. An AC generator comprising a magnet rotor according to claim 3 and a stator in which a coil is wound and is disposed opposite to said permanent magnets. An AC generator (1) comprises a magnet rotor (3) which is fixed to a rotating shaft (2) and a stator (4). The magnet rotor (3) comprises a boss (10) which is fixed by caulking to a center of a yoke (11) in which permanent magnets (12) are fixed, and a rotating shaft (2) is fixed to the boss (10). A socket and spigot type clutch alignment member (22) is formed by forming a recess (20) on a bottom (15) of the yoke (11), and an outer race (31) of a one-way clutch mechanism (30) is aligned and fixed by the socket and spigot type clutch alignment member (22). As a result, the magnet rotor is made smaller and the fabrication of the magnet rotor becomes easy.

Documents:

05073-kolnp-2007-abstract.pdf

05073-kolnp-2007-claims.pdf

05073-kolnp-2007-correspondence others.pdf

05073-kolnp-2007-description complete.pdf

05073-kolnp-2007-drawings.pdf

05073-kolnp-2007-form 1.pdf

05073-kolnp-2007-form 3.pdf

05073-kolnp-2007-form 5.pdf

05073-kolnp-2007-international publication.pdf

05073-kolnp-2007-international search report.pdf

05073-kolnp-2007-others.pdf

05073-kolnp-2007-pct priority document notification.pdf

5073-KOLNP-2007-(21-04-2014)-ABSTRACT.pdf

5073-KOLNP-2007-(21-04-2014)-CLAIMS.pdf

5073-KOLNP-2007-(21-04-2014)-CORRESPONDENCE.pdf

5073-KOLNP-2007-(21-04-2014)-DESCRIPTION (COMPLETE).pdf

5073-KOLNP-2007-(21-04-2014)-DRAWINGS.pdf

5073-KOLNP-2007-(21-04-2014)-FORM-1.pdf

5073-KOLNP-2007-(21-04-2014)-FORM-2.pdf

5073-KOLNP-2007-(21-04-2014)-FORM-3.pdf

5073-KOLNP-2007-(21-04-2014)-OTHERS.pdf

5073-KOLNP-2007-(21-04-2014)-PA.pdf

5073-KOLNP-2007-(21-04-2014)-PETITION UNDER RULE 137.pdf

5073-KOLNP-2007-ASSIGNMENT.pdf

5073-KOLNP-2007-CORRESPONDENCE OTHERS 1.1.pdf

5073-KOLNP-2007-CORRESPONDENCE OTHERS 1.2.pdf

5073-kolnp-2007-form 18.pdf

5073-KOLNP-2007-FORM 3.1.pdf

5073-KOLNP-2007-GPA.pdf

abstract-05073-kolnp-2007.jpg