Title of Invention

"COOLING APPARATUS FOR A WATER-COOLED ENGINE"

Abstract

For a pair of a right face 10 and a left face 11, opposite to each other with the cylinder 16 of the body 1 approximately in the a shape of a rectangular parallelepiped interposed in-between, the pump mounting concave 41 and the water jacket 45 are formed by die casting with the molds removed in left and right directions, and the water jacket 45 in the right face 10 is covered with the inlet cover 2. The pump mounting concave 41 in the left face 11 is fitted with the pump body 43 of the water pump 40 and capped. In the center of the pump body 43, there is provided an opening for the water passage 43a which communicates with the water jacket 45, and the impeller 46 is made to face the water jacket 45 through the water passage 43a. In the front face 12, there are formed the water outlet port 56 and water inlet port 57, next to each other. The water outlet port 56 is connected with the water pump 40 via the communicating path 59, the water inlet port 57 is connected directly with the water jacket 45, and the radiator 60 is fixed directly to the front face 12 of the body 1 with the return port 61 and water supply port 62 of the radiator 60 being fitted into the water outlet port 56 and water inlet port 57. Selected Drawing :

Full Text

NADetailed Description of the Invention [Field of the Invention] t The present invention relates to a cooling apparatus for a water-cooled Engine outlet and inlet ports for interconnecting a water jacket with a radiator in a water-cooled engine. [Prior art] Up to now, the cooling water outlet and inlet ports in a water-cooled engine have been disposed in either of the following ways. (1) Providing an inlet port in a cylinder and an outlet port in a cylinder head (or the reverse thereof, for instance, Japanese Utility Model Laid-Open Publication • No. 71734-1992) (2) Of a pair of faces opposite to a cylinder or cylinder head, one face is provided with an inlet port and the other face is provided with an outlet port. [0003] [Problem to be Solved by the Invention] In the case of the construction of (1), both the cylinder and the cylinder head have to be fabricated in them respectively, while in the case of the construction of (2), cooling water inlet and outlet ports have to be fabricated in two directions on two different faces of a cylinder or cylinder head. Accordingly, in either case, at least two stages of fabrication are required. Besides, it is likely that a cooling water outlet/inlet passage would become complicated and that passage resistance would increase. [0004] How to Solve the Subject Matter In order to solve the above mentioned problem, a cooling system for a water-cooled engine according to a first feature of the invention comprises a water jacket formed around the cylinder of an engine, a water pump provided on one face of the engine surrounding the water jacket, and a water outlet/inlet passage for interconnecting the water jacket with a radiator provided on the other face approximately orthogonal to the face having the water pump. [0005] In addition to the first feature, in the cooling system for a water-cooled engine according to a second feature, the radiator communicatejs directly with the water jacket of the engine via the water outlet/inlet passage. [0006] In addition to the second feature, in the cooling system for a water-cooled engine according to a third feature, the radiator is fixed directly to the engine. [0007] In addition to the first feature, in the cooling system for a water-cooled engine according to a fourth feature, a circular periphery is provided on a pump body composing the water pump, a circular pump housing is provided on the face of the cylinder , and the pump body is fitted into the pump body housing so that the outer periphery of the pump body is watertight, via a sealing member, with the inner peripheral surface of the pump body housing. In addition to the first feature, in the cooling system for a water-cooled engine according to a fifth feature, the water outlet/inlet passage is set at a location approximately equal to a width of the water jacket. In addition to the fourth feature, in the cooling system for a water-cooled engine according to a sixth feature, the water outlet/inlet passage on the outlet side is interconnected with a communicating path formed in the pump body of the water pump. In addition to the sixth feature, in the cooling system for a water-cooled engine according to a seventh embodiment, a sealing protrusion is provided in the outlet side of the passage for forming a seal between the outer periphery of the pump body and the inner peripheral surface of the pump body housing. Effects of the Invention According to the first feature of the invention, since the water outlet/inlet passage for interconnecting the water jacket with the radiator is provided on the other face approximately orthogonal to the face having the water pump of the engine, cooling water outlet and inlet ports can be fabricated in the same face in a single process, thereby contributing to reducing man-hours. According to the second feature, since the radiator communicates directly with the water jacket of the engine via the water outlet/inlet passage, cooling water flows straight from the engine into the radiator, and flows out in a single turn, thereby contributing to making a simpler route and reducing passage resistance to a minimum. According to the third feature, since the radiator is directly fixed to the body 1, the passage of cooling water between the engine and radiator can be shortened as much as possible, thereby contributing to reducing the number of parts such as water hoses, as well as to making a smaller installation space for the radiator. According to the fourth feature, since the outer periphery of the pump body and the inner periphery of the pump housing are made circular and fitted together watertightly via a sealing member, the water pump can not only be directly mounted on the side of the cylinder but can also be sealed in a simple and secure fashion. According to the fifth feature, since the water outlet/inlet passage is set at a location approximately equal to a width of the water jacket, the passage resistance can be reduced. According to the sixth feature, since the outlet side of the water outlet/inlet passage interconnects with the communicating path formed in the pump body of the water pump, a shortest possible connection of a route between the water pump and radiator body can be made without using any other piping members. In addition to the sixth feature, in the cooling system for a water-cooled engine according to a seventh feature, a sealing protrusion is provided in the outlet side of the passage for forming a seal between the outer periphery of the pump body and the inner peripheral surface of the pump body housing. Accordingly, the present invention relates to a cooling apparatus for a water-cooled engine, comprising: a water jacket formed around a cylinder of an engine; a water pump provided on one face of the engine surrounding the water jacket; Characterized in that: a water outlet/inlet passage for interconnecting the water jacket to a radiator provided on another face of the engine in a direction approximately orthogonal to the face having the water pump.Brief Description of the/Drawings Fig. 1 is a sectional view of the surrounds of a water jacket taken along the line 1-1 in Fig. 2. Fig. 2 is an overall sectional view of the engine involved in the present embodiment. Fig. 3 shows the right face with an inlet cover removed. Fig. 4 shows the left face with a cam chain cover removed. Fig. 5 shows the joint face of an inlet cover. Fig. 5 is a sectional view of a mold illustrating a method for forming a water jacket. [Description of the Preferred Embodiment] A preferred embodiment of the invention as applied to a water-cooled 4-cycle small displacement engine for use in a lightweight motor bicycle will now be described >n detail with reference to the drawings. Fig. 1 is a sectional view taken along the line 1-1 of Fig. 2 showing the surrounds of a water jacket of an engine involved in this embodiment; Fig. 2 is an overall sectional view of the engine; Fig. 3 shows the right face of the body with an inlet cover removed; Fig. 4 shows the left face of the body with a cam chain cover removed; Fig. 5 shows the joint face of the inlet cover; and Fig. 6 is a sectional view of a mold construction showing how the water jacket is formed. The engine is designed so that it can be assembled and mounted on a crankcase (not shown) by fixing an inlet cover 2 and cam chain.Cover 3 to two faces opposite to each other approximately in parallel formed in the lengthwise direction with respect to a body 1 approximately in the shape of a rectangular parallelepiped. The body 1 has an integral cylinder 5 for housing a piston 4 that is interconnectedwith a crankshaft (not shown) via a connecting rod 4a as well as a head 8 that is provided with a cam room 7 for rotatably housing a cam shaft 6. As a way of casting, die casting may be adopted which employs such appropriate metals as aluminum alloy. In this application, a portion of the head 8 which covers the cam room 7 is particularly called a head cover 9, and for the sake of convenience, faces of the body 1 are each called as follows: the face on which the inlet cover 2 is fixed is called a right face 10, the face on which the cam chain cover 3 is fixed is called a left face 11, of two faces opposite to each other approximately orthogonal being sandwiched between the two faces, one on which a radiator to be described later is fixed is called a front face 12, and the other is called the back face 13. Furthermore, the outer surface of the ceiling of the head cover 9 is called a top face 14, and the face to be fixed to the crankcase is called a bottom face 15. In the cylinder section 5, a cylinder 16 extends from the side of the bottom face 15 up to an approximately intermediate point in the lengthwise direction of the body 1. A combustion chamber 17 formed on the side of the head 8, the deepest portion of the cylinder 16, is interconnected with an inlet port 18 and exhaust port 19, and the opening of each port on the side of the combustion chamber 17 is opened/closed by an inlet valve 20 and an exhaust valve 21. Each valve axis Cl and C2 is at a specified included angle with respect to the cylinder axis C RefeRenee numerals 20a and 2la denote stem holders. The inlet port 18 interconnects with an intake air passage 22 formed in the inlet cover 2, which extends obliquely in an outward direction on an extension of the inlet port 18 to connect with a carburetor (not shown) via an inlet pipe 23. The exhaust port 21 extends bending approximately at a right angle with respect to the inlet port 18 to connect with an exhaust pipe 24 at the back face 13. The symbol 29 in Figs. 2 and 3 denotes a spark plug. Valves are each driven directly by cams 27 and 28 via valve lifters 25 and 26 provided at ends of the respective shafts. The cam shaft 6 provided with the cams 27 and 28 is supported by bearings 30 and 31 at the ends of both openings in the cam room 7 which is tapered and runs through between the right face 10 and left face 11. The sliding surfaces of the cams 27 and 28 slant in correspondence to the slanting sliding surfaces of the valve lifters 25 and 26 respectively. An oil feeder 6a is formed between one end of the cam shaft 6 and the inlet cover 2 . The other end of the cam shaft 6 protrudes into a chain room 32 formed between the cam chain cover 3 and the left face 11, and a cam sprocket 33 is fixed at the end of the protrusion by means of bolts 33. The cam sprocket 33 is connected to a drive sprocket provided on a crank shaft not shown via a cam chain 35. Cam peep holes 36 and 37, which are coaxial with the valve axes Cl and C2 respectively and have a diameter approximately identical to that of the valve lifters 25 and 26 are formed on the extensions of the valve axes Cl and C2 in the head cover 9. The cam peep holes 36 and 37 are provided with caps 38 and 39 for opening/closing the cam room 7 tightly enclosed via a seal by means of screws.The composition around the water jacket will now be described. A water pump 40 is provided in the vicinity of the combustion chamber 17 of the body 1. As is clear from Fig. 4, a pump mounting concave 41 is formed in a side wall of the left face 11 opposite to the cam chain cover 3 of the body 1, for housing a flange 42 formed in an area of a resin cover of an outer shape of the water pump 40. The flange 42 is also approximately as circular as the pump mounting concave 41, and is fitted watertightly into the inner peripheral wall of the pump mounting concave 41 via an 0-ring 44, and is sealed therebetween. As is clear from Fig. 1, the flange 42 and a pump body 43 which is integrated with the flange 42 are housed together in the pump mounting concave 41 by means of screws or the like, being in contact with the bottom 41a. In the bottom 41a an opening 41b is formed leading to a water jacket 45, while a guide 43a which fits into the opening 41b and protrudes into the water jacket 45 is formed in the bottom of the pump body 43, ard by fitting the pump body 43 into the pump mounting concave 41, the opening 41b into the bottom 41a, namely the opening of the water jacket 45, is covered with the pump body 43. The guide 43b in the pump body 43 has a concave guide surface surrounding the periphery of the cylinder 16 at specified intervals approximately in a shape of a semicircle as viewed in the direction of the cylinder axis C. Both ends in forward and backward directions (the direction connecting the front face 12 and back face 13) of the guide 43b protrude into the inlet cover 2, so as to be fitted into and come into contact with the inner surface of the front face 12 and back face 13. The guide 43b has the water jacket 45 formed between the guide surface thereof and the cylinder 16, with an opening formed at the center thereof, thereby providing a water passage 43a which interconnects the pump body 43 with the water jacket 45. The guide surface enables cooling water in the water jacket 45 to be guided toward the water passage 43a. The water passage 43a is provided with an impeller 46 which is integrated with and rotatably supported by a pump shaft 47. One end of the pump shaft 47 protrudes into the outer peripheral wall of the cylinder 16, and is rotatably supported by a boss 48 which protrudes into the water passage 43a. The other end of the pump shaft 47 protrudes over a cam chain 35 into a cam room 32. A magnet ring 49 is provided on the periphery thereof, and the periphery is further covered with a portion of a resin cover which is integral with the flange 42, thereby forming a circular small diameter section 50. The protruding end of the small diameter section 50 is fitted into and supported by a circular fitting concave 51 formed in the cam chain cover 3. As is shown in Fig. 4, the center of the small diameter section 50 deviates from that of the flange 42. The center of the fitting concave 51 (Fig. 1) which is concentric with the small diameter section 50 also deviates from that of the pump mounting concave 41 which is concentric with the flange 42. Because of this, fitting the small diameter section 50 into the fitting concave 51, fitting the flange 42 into the pump mounting concave 41, and mounting the cam chain cover 3 on the left face 11 by means of screws or the like enables the water pump 40 to be easily positioned and fixed in a specified location inside the pump mounting concave 41. As is clear from Fig. 1, on the outer periphery of the small diameter section 50, there is provided a water pump sprocket 53 with a magnet ring 52 integrated in the inner periphery thereof , so as to be driven by the cam chain 35. The outer periphery of the boss of the water pump sprocket 53 is rotatably housed via a bearing 54 into a bearing section 55 formed in the cam chain cover 3.- When the magnet ring 52 is rotated integrally with the water pump sprocket 53, it causes the magnet ring 49 inside the small diameter section 50 to be magnetically connected and integrally rotated, thereby rotating the impeller 46 via the pump shaft 47 integrated with the magnet ring 49, thus allowing the water pump 40 to be driven. A water outlet port 56 and water inlet port 57 are formed on the front face of the body 1 disposed side by side and protrude into a width W (Fig. 1) of the water jacket 45. Here, the width W of the water jacket 45 with respect to the position where the water outlot port 56 and water inlet port 57 are formed is the width between the right face 10 where the opening 45a is formed at the right face of the water jacket 45 and the left face 11 where the pump mounting concave 41 opens. The water outlet port 56 is formed in the vicinity of the cam chain cover 3, and a sealing protrusion 58 is formed inside the water outlet port 56, at the joint with the pump body 43, extending into the passage to interconnect at the end of this narrowed passage with a communicating path 59 provided on the pump body 43. The fact that the protrusion 58 coincides with an 0-ring 44 as viewed from the outside of the water outlet port 56 allows the face opposite to the pump body 43 to become a sealing surface of the O-ring 44. The communicating path 59 extends from the periphery of the pump body 43 toward the impeller 46 linearly and radially, providing a circular discharge path for the water pump around the impeller 46. The water inlet port 57 is located in the vicinity of the inlet cover 2, and communicates directly with the water jacket 45. The return port 61 and water supply port 62 of a radiator 60 are directly fitted into the water outlet port 56 and water inlet port 57, respectively, and are respectively connected thereto, enabling the radiator to be directly fixed to the front face 12 of the body 1. The return port 61 is connected with an upper tank 63 via a return path extending linearly in the radiator 60 in a direction of the extension of the communicating path 59, which contributes to making a shorter passage and reducing passage resistance. Inside the water jacket 45 are the guide 43b protruding from the pump body 43 and the protrusion 70 of the inlet cover 2 being fitted.from the opposite direction each other, so as to form the water jacket 45 by enclosing the cylinder 16 at specified intervals. The face of the protrusion 70 opposite to the cylinder 16 has a guide surface similar to that of the guide 43b, enabling cooling water inside the water jacket 45 to flow smoothly into the water path 43a without stopping. Opposite ends 72 and 73 of the protrusion 70 also protrude into the side of the water pump 40, and are fitted into and are in contact with the inner surface of the front face 12 and back face 13 of the body 1, respectively. Additionally, a relief is partly formed in the vicinity of the water inlet port 57 of the guide 73 to provide an expanded space for allowing easy flow of cooling water from the radiator 60 into the water jacket 45. Also, at the side of the outer surface of the protrusion 70 in the inlet cover 2 there are integrally formed cooling fins 75, which contribute to enhancing the cooling efficiency of the cooling water of the water jacket 45. As is shown in Fig. 5, on the joint face of the inlet cover 2 fixed to the right face of the body 1 there are formed a rectangular cooling seal 65, an oval suction seal 66 and an oil seal 67 which is approximately P-shaped. By laying the inlet cover 2 on the right face 10, water, fuel-air mixture and oil are divided and sealed between the right face 10 and inlet cover 2. Additionally, reference numeral 67 in Fig. 5 denotes a concave communicating with an oil path 67a (Fig. 1) leading to a main gallery (not shown), and the symbol 68 denotes an oil path for supplying oil to the oil feeder 6a (Fig. 2) formed at the end of the cam shaft. Fig. 6 shows a mold for forming the water jacket 45. A protrusion 85 in a right mold 80 as well as a protrusion 87 in a left mold 80 are provided with respective semi-circular molding surfaces 86 and 88 respectively, which surround a cylinder mold in a ring form with a gap as thick as the cylinder 16. A front face mold 82 is provided with casting pins 90 and 92 for casting the water outlet port 56 and water inlet port 57, as well rs with a protrusion 91 for forming a concave in the intermediate section thereof. The symbol 83 denotes a back face mold. Thus, the water jacket 45 is molded from the left and right directions by the right mold 80 and left mold 81, the pair of molds being disposed opposite to each other with the cylinder 5 held in a direction orthogonal to the cylinder axis C, so as to open to the side of the cylinder 5. A description will now be given of how the embodiment operates. As is clear from Fig. 1, while the water outlet port 56 and water inlet port 57 to which the radiator 60 is connected within the width W of the water jacket 45 are provided in the front face 12 that is approximately orthogonal to the left face 11 in which the water pump 40 of the body 1 is provided, the radiator 60 is directly fixed to the front face 12 of the body 1 by fitting the return port 61 and water supply port 62 of the radiator 60 into the water outlet port 56 and water inlet port 57. As a result, the cooling water outlet and inlet ports can be die-cast in a single process in the same face of the body 1, which results in a reduction of man-hours. In addition, the simpler path for cooling water to flow straight from the water jacket 40 into the radiator 60 as well as to flow out straight in a single turn via the water outlet port 56 and water inlet port 57 contributes to reducing passage resistance to a minimum. Furthermore, since the radiator 60 is directly fixed to the body 1, the passage of cooling water between the body 1 and radiator 60 is shortened as much as possible, thereby contributing to reducing the number of parts such as water hoses as well as to requiring a smaller space for installation of the radiator 60. Also, since the outer periphery of the pump body 43 and the inner periphery of the pump housing 41 are made circular and fitted watertightly via the O-ring, the water pump 40 can not only be directly mounted on the side of the cylinder 5 but can also be sealed in a simple and secure fashion. In addition, since the water outlet port 56 interconnects with the communicating path 59 formed in the pump body 43 of the water pump 40, a shortest possible connection of a route between the water pump 40 and radiator body 60 can be made without using any other piping members. Furthermore, since the sealing protrusion 58 is formed in the water outlet port 56, sealing surfaces for the pump body 43 and pump body housing 41 at the water outlet port 56 can easily be secured. Furthermore, since the body 1 has three major components, namely the cylinder 5, head 8 and head cover 9, die-cast as one piece by using molds, the sections forming the water outlet port 56 and water inlet port 57 are a continuation of a single component from the cylinder 5 to head 8. Thus, the water outlet port 56 and water inlet port 57 can be set not only in the cylinder 5 but also in the head 8. Otherwise, they can be set by distributing them either to the cylinder 5 or the head 8, without bringing about any effect on the aforesaid integral forming process. Hence, the degree of freedom thereof is great. Furthermore, since the water jacket 45 is molded from left and right directions by the right mold 80 and left mold 81, the pair of molds being disposed opposite to each other with the cylinder 5 being held in a direction orthogonal to the cylinder axis C, so as to open to the side of the cylinder 5, the core which has been necessary in the past can be done away with, thereby eliminating a lot of man-hours which have been required for fabricating cores as well as for removing sand, and resulting in reduced numbers ^f processes and workers as well as in easier splitting of a mold construction. Also, there is no longer any need to pay attention to the seizing of a mold for a water jacket as is the case when die-casting is employed, which contributes to improving the precision of the water jacket 45 as well as to a greater degree of freedom in terms of configuration. An embodiment of the present invention has been described so far. However, the invention may be embodied with various changes applied thereto without departing from the spirit and scope of the invention. For instance, the body 1 may be assembled with the cylinder 5 and head 8 being formed separately. In this case, however, the water-outlet port 56 and water inlet port 57 are to be formed so as to be disposed side by side in either the cylinder 5 or the head 8. Moreover, it is not necessary to employ die-castirg as a molding method. Instead, any other publicly known molding method may be used such as a sand molding. Description of the Reference Numerals 1 : Body, 2 : Inlet cover, 3 : Cam chain cover, 5 : Cylinder section, 6 : Cam shaft, 7 : Cam room, 8 : Head, 9 : Head cover, 16 : Cylinder, 32 : Chain room, 35 : Cam chain, 40 : Water pump, 41 : Pump mounting concave (Body housing), 42 : Flange, 43 : Pump body, 43a : Water path, 45 : Water jacket, 46 : Impeller, 56 : Water outlet port, 57 : water inlet port, 58 : Sealing protrusion, 59 : Communicating path, 60 : Radiator We claim: 1. A cooling apparatus for a water-cooled engine, comprising: a water jacket (45) formed around a cylinder (16) of an engine; a water pump (40) provided on one face of the engine surrounding the water jacket (45); Characterized in that: a water outlet (56)/inlet (57) passage for interconnecting the water jacket (45) to a radiator (60) provided on another face of the engine in a direction approximately orthogonal to the face having the water pump (40). 2. A cooling apparatus for a water-cooled engine as claimed in claim 1, wherein the said radiator (60) communicates directly with the said water jacket (45) of the engine via the said water outlet (56)/inlet (57) passage. 3. A cooling apparatus for a water-cooled engine as claimed in claim 2, wherein the said radiator (45) is directly fixed to the said engine. 4. A cooling apparatus for a water cooled engine as claimed in claim 1, wherein said water pump (40) composed in a pump body (43) is provided with circular periphery provided on said pump body (43) with on its side a circular pump housing, the said pump body is fitted into the said pump body housing so that the outer periphery of the said pump body is watertight through a sealing member, with the inner peripheral surface of the said pump body housing. 5. A cooling apparatus for a water cooled engine as claimed in claim 1, wherein the said water outlet (56)/inlet (57) passage is set at a location approximately equal to a width of the water jacket. 6. A cooling apparatus for a water cooled engine as claimed in claim 4, wherein said water outlet (56)/inlet (57) passage on the outlet side is interconnected to a communicating path formed in the pump body (43) of the water pump. 7. A cooling apparatus for a water cooled engine as claimed in claim 6, wherein the said outlet side of the said passage is provided with a sealing protrusion (59) for forming a seal between the said outer periphery of the said pump body (43) and the said inner peripheral surface of the said pump body (43) housing. 8. A cooling apparatus for a water cooled engine substantially as herein described with reference to and as illustrated in the foregoing description and the accompanying drawings.

Documents:

2531-del-1998-abstract.pdf

2531-del-1998-claims.pdf

2531-del-1998-correspondence-others.pdf

2531-del-1998-correspondence-po.pdf

2531-del-1998-description (complete).pdf

2531-del-1998-drawings.pdf

2531-del-1998-form-1.pdf

2531-del-1998-form-13.pdf

2531-del-1998-form-19.pdf

2531-del-1998-form-2.pdf

2531-del-1998-form-3.pdf

2531-del-1998-form-4.pdf

2531-del-1998-form-6.pdf

2531-del-1998-gpa.pdf

2531-del-1998-petition-137.pdf

2531-del-1998-petition-138.pdf

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