JP4246016B2 - Engine cooling structure - Google Patents

Description

  The present invention relates to an engine cooling structure for cooling a cylinder of an engine of a motorcycle.

  A radiator, a water pump, and a cylinder are connected by pipes to one of the conventional engine cooling structures of a water-cooled motorcycle, and the cooling water is configured to circulate through each of the radiator, the water pump, and the cylinder. There is something.

  However, in the conventional engine cooling structure as described above, since the pipes are disposed in the vicinity of the engine, these pipes are exposed to the outside. The structure of the engine and its surroundings is complex, and many parts need to be attached to or removed from these parts in the manufacture, repair or maintenance of a motorcycle, but the pipes are arranged in the vicinity of the engine. Then, these pipes may interfere with the attachment or removal of parts.

  Moreover, it is not preferable that such a pipe is exposed in the vicinity of the engine from the viewpoint of the aesthetic appearance of the entire motorcycle. In particular, there is no cowling that covers the periphery of the engine of the so-called American type or naked type, and this point is important in motorcycles that have an exposed engine, so that such pipes are not exposed to the outside as much as possible. It has long been desired to configure.

  The present invention has been made in view of such circumstances, and a part of the cooling water channel of the engine is not exposed to the outside, and it is possible to easily attach or remove parts around the engine as compared with the conventional case. Another object of the present invention is to provide an engine cooling structure that can be expected to improve the aesthetic appearance of the entire motorcycle.

In order to solve the above problems, an engine cooling structure according to the present invention includes a water pump that discharges cooling water for cooling a cylinder of a motorcycle engine, and the cooling water discharged from the water pump to the cylinder. A water supply channel, a crankcase that forms a crank chamber and a transmission chamber, and a mission cover that covers the outside of the crankcase, and the opposing portions of the crankcase and the mission cover each have a recessed shape. None, the circumferential joint end face of the crankcase is joined to the circumferential joint end face of the mission cover, and the crankcase and the mission cover have grooves on the inner peripheral side along the joint end face, respectively. Provided by joining the joining end faces to each other so that both grooves meet. At least a part of a water channel is formed, and the pump casing of the water pump is formed integrally with the crankcase and the transmission cover, and the groove of the crankcase has the crank chamber and the transmission. It is provided between the rooms.

  By adopting such a configuration, a part of the water channel is not exposed to the outside, and it is possible to easily attach or remove parts around the engine as compared with the conventional one, and the aesthetics of the entire motorcycle. It can be expected to improve the appearance.

In addition, by in along a bonding surface of each of the sea Tsu Deployment cover covering the outside of the crankcase and the crankcase which also serves as a transformer transmission case providing a groove, crankcase及beauty mission-cover formed integrally with the waterway It can be expected that the length of the formed portion is sufficiently secured and the number of water channels (pipes) exposed to the outside is further reduced.

Further, by the crank chamber and the transmission chamber to the crank case is formed, in many cases there is a relatively large excess space between the crank chamber and the transmission chamber, the groove in such a compensation volume portion of the crankcase By providing the (water channel), an increase in the size of the crankcase caused by integrally molding the water channel can be suppressed.

Further, by the Turkey pump casing of c Otapon flops are formed in the crankcase及beauty mission-cover integrally, as compared with the case where the transmission case and the water pump provided separately from an engine, including a transmission and water pump The size of the unit can be reduced.

  In the case of the engine cooling structure according to the present invention, a part of the water channel is not exposed to the outside, and it is possible to easily attach or remove parts around the engine as compared with the prior art, and It can be expected to improve the aesthetic appearance of the entire motorcycle.

  Hereinafter, an engine cooling structure according to an embodiment of the present invention will be specifically described with reference to the drawings.

  FIG. 1 is a side view showing the appearance of a motorcycle having an engine cooling structure according to an embodiment of the present invention. As shown in FIG. 1, the motorcycle 1 according to the present embodiment is of a so-called American type, is not provided with a cowling that covers the engine E, and the engine E is exposed to the side. The engine E is disposed between the front wheel 2 and the rear wheel 3 that is a driving wheel, and is attached to a frame 4 that forms a vehicle body of the motorcycle 1. A side stand 5 is provided on the left side of the frame 4. In addition, the vertical direction, the front-rear direction, and the left-right direction in the present embodiment mean the vertical direction, the front-rear direction, and the left-right direction as viewed from the driver who has boarded the motorcycle 1.

  2 is a partial cross-sectional left side view of the engine according to the embodiment of the present invention, and FIG. 3 is a partial cross-sectional right side view thereof. The engine E is a V-type two-cylinder four-cycle engine, and is provided below the two cylinders 6 and 7 and two cylinders 6 and 7 arranged in front and rear so as to form a substantially V shape in a side view. A crankcase 8 and an oil pan 9 provided below the crankcase 8. The cylinders 6 and 7 have cylinder heads 6a and 7a at the upper portions thereof, respectively, and valve operating systems (not shown) such as valves and rocker shafts.

  FIG. 4 is an exploded perspective view showing main housing parts of the engine E excluding the cylinders 6 and 7. As shown in FIG. 4, the engine E includes a left crankcase 10 and a right crankcase 11 that are paired on the left and right. The crankcase 8 is configured by the left crankcase 10 and the right crankcase 11 being abutted and fastened from the left and right. The left crankcase 10 and the right crankcase 11 are formed with a plurality of concave portions at respective opposing portions, and the edge portions forming the concave portions and the end surfaces of the wall portions are joined to each other to thereby form a plurality of internal portions. A crank chamber 20, a transmission chamber 21, an output shaft chamber 22, and a separator chamber 23, which are spaces, are formed in the crankcase 8.

  A left side portion (outer side portion) of the left crankcase 10 is recessed to the right side and is formed in a concave shape, which constitutes a part of the clutch chamber 24. An inner clutch cover 12 having a concave shape on the right side is attached to the left crankcase 10 from the left side, and the peripheral edges of the inner clutch cover 12 are joined to each other. It is attached. As a result, a clutch chamber 24 that is a space substantially closed by the left crankcase 10, the inner clutch cover 12, and the outer clutch cover 13 is formed.

The left crankcase 10, the inner clutch cover 12, and the outer clutch cover 13 are formed with an oil reservoir 24 a whose inner bottom is recessed downward. Oil collected in the clutch chamber 24 is stored in the oil reservoir 24a.

  A cam cover 14 is attached to the front side of the right side (outer side) of the right crankcase 11. Opposite portions of the right crankcase 11 and the cam cover 14 are each recessed in a concave shape, and the peripheral edge of the cam cover 14 is joined to the joining end surface of the cam cover 14 provided on the right side of the right crankcase 11. ing. Thereby, a cam chamber 25 which is a space surrounded by the right crankcase 11 and the cam cover 14 is formed. In the cam chamber 25, a cam, a cam chain and the like which will be described later are housed.

  Further, an inner mission cover 15 is attached to a position near the right side of the right crankcase 11, and an outer mission cover 17 is attached to the right side of the inner mission cover 15. The inner mission cover 15 and the outer mission cover 17 constitute a transmission cover according to the present invention. Opposite portions of the right crankcase 11 and the inner mission cover 15 have a recessed shape, and the peripheral end face (joint surface according to the present invention) of the inner mission cover 15 is provided on the right side of the right crankcase 11. The inner transmission cover 15 is joined to the joining end face (joint face according to the present invention). Further, the opposing portions of the inner mission cover 15 and the outer mission cover 17 are also recessed in a concave shape, and the end surfaces of the respective peripheral edges are joined. An internal space formed by the inner mission cover 15 and the outer mission cover 17 forms an oil storage chamber 26.

  FIG. 5 is a left side view of the inner mission cover according to the embodiment of the present invention, and FIG. 6 is a right side view of the right crankcase according to the embodiment of the present invention. As shown in FIG. 5, a hemispherical concave portion 150 is provided on the front side of the inner mission cover 15 on the side where the right crankcase 11 is joined. A long groove 151 is extended. The lower end of the groove 151 communicates with the recess 150. The recess 150 and the groove 151 are provided at a joint portion of the inner mission cover 15 with the right crankcase 11, and the periphery of the recess 150 and the groove 151 is a joint surface 152 with the right crankcase 11.

  Further, as shown in FIG. 6, a concave portion 153 and a groove 154 corresponding to the concave portion 150 and the groove 151, respectively, are provided in a substantially central portion on the right side of the right crankcase 11 in the front-rear direction. The recess 153 is closed with the recess 150 to form a pump casing 127a, which will be described later, and accommodates a rotor 128 and a pump shaft 129, which will be described later. The groove 154 has a lower end communicating with the recess 153 and has a shape extending in the vertical direction in the same manner as the groove 151. The concave portion 153 and the groove 154 are provided at the joint portion of the right crankcase 11 with the inner mission cover 15, and the periphery of the concave portion 153 and the groove 154 is a joint surface 155 with the inner mission cover 15.

  As shown in FIG. 4, the joining surface 155 of the right crankcase 11 and the joining surface 152 of the inner mission cover 15 are abutted, and the right crankcase 11 and the inner mission cover 15 are joined. A pump casing 127a (see FIG. 8) is formed by the recesses 150 and 153, and a water channel 156 (see FIG. 3) described later is formed by the grooves 151 and 154.

  As shown in FIG. 4, an oil pan 9 is attached to the lower part of the left crankcase 10 and the right crankcase 11. As a result, the oil pan 9 is located below the crank chamber 20 and the transmission chamber 21.

  In addition, although not shown in figure, the sealing member is interposed between each member mentioned above, and gas and liquid do not leak from the connection location between each member.

  7 is a VII-VII cross-sectional view of the engine E shown in FIG. As shown in FIG. 7, in the engine E, the crank chamber 20 is located below the cylinders 6 and 7, and a transmission chamber 21 is disposed behind the crank chamber 20. The transmission chamber 21 is also used as an oil tank.

  An output shaft chamber 22 is disposed behind the transmission chamber 21, and a right side portion of the transmission chamber 21 extends rearward along the right side portion of the output shaft chamber 22. A separator chamber 23 is disposed behind the output shaft chamber 22. Further, a clutch chamber 24 is disposed on the left side of the engine E and on the left side of the crank chamber 20 and the transmission chamber 21, and an oil storage chamber 26 is disposed on the right side of the engine E and on the right side of the transmission chamber 21. Has been placed.

  The crank chamber 20, the transmission chamber 21, the output shaft chamber 22, the separator chamber 23, and the clutch chamber 24 are integrally formed by a crank case 8 formed by closing the left crank case 10 and the right crank case 11. . Accordingly, the number of parts can be reduced as compared with the case where each of the chambers 20 to 24 is configured separately, so that the engine weight and the number of assembly work steps can also be reduced. Further, the engine E can be made compact.

  The left crankcase 10 and the right crankcase 11 described above are provided with a plurality of shafts for transmitting the power of the engine E. As shown in FIG. 7, a crankshaft 30 is accommodated in the crank chamber 20. Each of the left crankcase 10 and the right crankcase 11 is provided with a bearing portion 31, and the crankshaft 30 is rotatably supported by the bearing portion 31 so that the shaft core is directed in the left-right direction. A piston 34 is connected to the crankpin 32 of the crankshaft 30 via a connecting rod 33.

  The right end of the crankshaft 30 penetrates the right crankcase 11 and protrudes into the cam chamber 25, and is connected to cam sprockets 35 and 36 (see FIG. 3) via a chain. Further, the right end portion of the crankshaft 30 is also connected to balancer shafts 37 and 38 (see FIG. 3) disposed before and after the crankshaft 30 via a chain. The balancer shafts 37 and 38 rotate as the crankshaft 30 rotates, and the balancer shaft 38 disposed on the rear side drives an oil pump for sucking and pumping oil circulating in the engine E. .

  As shown in FIG. 7, a partition wall 39 formed in the left crankcase 10 is provided between the crank chamber 20 and the clutch chamber 24 to partition both chambers. The bearing 31 described above is provided through the partition wall 39. The left end portion of the crankshaft 30 passes through a bearing portion 31 provided in the partition wall 39 and protrudes into the clutch chamber 24, and a generator 40 for power generation is provided at the left end portion.

  A main shaft 41 and a counter shaft 42 are rotatably supported in the transmission chamber 21 such that the shaft cores are parallel to the crankshaft 30. The main shaft 41 and the counter shaft 42 are hollow tubular, and an oil passage 43 is formed in the inside thereof. A left end portion of the main shaft 41 passes through a partition wall 44 that partitions the transmission chamber 21 and the clutch chamber 24 and protrudes into the clutch chamber 24, and a clutch 45 is provided at the left end portion. The crankshaft 30 and the main shaft 41 are connected to each other through sprockets 46 and 47 and a chain 48 in the clutch chamber 24.

  The right end portions of the main shaft 41 and the countershaft 42 penetrate the inner mission cover 15, and an oil passage 43 formed in each shaft opens in the oil storage chamber 26. Therefore, the oil storage chamber 26 and the respective oil passages 43 in the main shaft 41 and the counter shaft 42 communicate with each other.

  The main shaft 41 and the counter shaft 42 are provided with a transmission 51 composed of a plurality of gears 50 having different diameters. When a driver operates a change lever (not shown), a predetermined gear 50 and a counter of the main shaft 41 are countered. A predetermined gear 50 of the shaft 42 is engaged with the shaft 42. In addition, a plurality of oil injection holes 52 that pass through the peripheral portions of the main shaft 41 and the counter shaft 42 to the internal oil passage 43 are provided at the base positions of the plurality of gears 50 that form the transmission 51.

  An output shaft 53 is rotatably supported in the output shaft chamber 22 so that the axis is parallel to the counter shaft 42. The right end portion of the output shaft 53 protrudes from the output shaft chamber 22 to the transmission chamber 21. The right end portion of the output shaft 53 and the right end portion of the counter shaft 42 are provided with gears that mesh with each other, and the rotational force of the counter shaft 42 is transmitted to the output shaft 53 via the gears.

  The left end portion of the output shaft 53 protrudes from the output shaft chamber 22 to the left side of the left crankcase 10, and a pulley 54 is provided at the left end portion. A belt is stretched between the pulley 54 and the shaft of the rear wheel 3 (see FIG. 1) of the motorcycle 1 so that the rotational force of the output shaft 53 is transmitted to the rear wheel 3. .

  FIG. 8 is a VIII-VIII cross-sectional view of the engine E shown in FIG. As shown in FIG. 8, the left crankcase 10 is integrally formed with a partition wall 70 that partitions the crank chamber 20 and the transmission chamber 21, and the crank chamber 20, the transmission chamber 21, and the cylinder are formed below the partition wall 70. An oil pump 71 is provided for sending oil to the heads 6a, 7a and the like. As shown in FIG. 8, the oil pump 71 includes a crank chamber scavenging pump 72, a clutch chamber scavenging pump 73, and a feed pump 74 in order from the right side of the engine E. Each rotor, port member, and the like are housed in an integrally formed pump casing 75.

  The pump cover 120 is provided at the opening end provided at the left end of the pump casing 75 in a state where the rotor and port member of the oil pump 71 described above are accommodated in the pump casing 75. A pump shaft 85 passes through the approximate center of the pump cover 120, each rotor, and each port member along the axis of the pump casing 75, and one end portion 122 of the pump cover 120 projects from the pump cover 120 to the outside (left side). Yes. The one end portion 122 is provided with a sprocket 123, and is connected to a rear balancer shaft 38 (see FIG. 2) via a chain 124.

  Further, the other end portion 125 of the pump shaft 85 passes through a bearing portion 86 formed at the closed end 81 of the pump casing 75 and protrudes to the outside (right side). The other end portion 125 is provided with a drive gear 126. The drive gear 126 drives a water pump 127 provided in the right crankcase 11 as shown in FIG.

  The pump casing 127a of the water pump 127 is integrally formed with the right crankcase 11 and the inner mission cover 15, as shown in FIG. Inside the pump casing 127a, a rotor 128 having a plurality of rotor blades and a pump shaft 129 for rotating the rotor 128 are housed. The drive shaft 126 is attached to the left end of the pump shaft 129, and the rotor 128 is fixed to the right end. An intermediate portion of the pump shaft 129 is rotatably supported by a bearing 130 attached to the right crankcase 11. With this configuration, the power of the engine E is transmitted to the balancer shaft 38 and the pump shaft 85 rotates, and this rotation is transmitted to the pump shaft 129 via the drive gear 126, and the oil pump 71 and the water pump. 127 is driven.

  As shown in FIG. 3, a radiator 140 is provided in front of the engine E. A pipe 141 through which the cooling water cooled by the radiator 140 flows is extended from the lower end of the radiator 140. As shown in FIG. 8, the pipe 141 is connected to the suction port 127 b of the water pump 127, and cooling water is supplied to the water pump 127 from the radiator 140.

  Further, as shown in FIG. 3, a water channel 156 for allowing cooling water discharged from the water pump 127 to flow up and down is inside the right crankcase 11 and the inner mission cover 15 and above the water pump 127. It extends in the direction. One end of a pipe 157 is connected to the outlet of the water channel 156, and the pipe 157 is connected to the cylinder 7. Cooling water discharged from the water pump 127 is supplied to the cylinder 7, and the cylinder 7 and The cylinder head 7a is used for cooling.

  Further, as shown in FIG. 2, a pipe 158 is installed between the cylinder 7 and the cylinder 6. One end of the pipe 158 is connected to the outlet of the water jacket (not shown) of the cylinder 7, and the other end is connected to the inlet of the water jacket (not shown) of the cylinder 6. The water is sent from the cylinder 7 to the cylinder 6. The cooling water supplied to the cylinder 6 flows through the water jacket provided in the cylinder 6 and the cylinder head 6a to cool the cylinder 6 and the cylinder head 6a.

  As shown in FIG. 2, pipes 159 and 160 are extended from the cylinder heads 6a and 7a, respectively, and the pipes 159 and 160 are joined at the tip to form one pipe 161. The end of the pipe 161 is connected to a thermostat 162, and a pipe 163 is passed between the thermostat 162 and the upper end of the radiator 140. Cooling water used for cooling is discharged from the cylinder heads 6 a and 7 a to the pipes 159 and 160, and this cooling water is supplied to the thermostat 162 through the pipe 161. The thermostat 162 sends the cooling water to the radiator 140 via the pipe 163 when the cooling water is at a predetermined temperature or higher. If the cooling water is lower than the predetermined temperature, the thermostat 162 again sends the cooling water to the cylinder 6. , 7 and cylinder heads 6a, 7a are used for cooling to the cylinders 6, 7 via pipes (not shown). In this way, the cooling water circulates through the radiator 140, the water pump 127 (see FIG. 3), the cylinders 6 and 7, and the cylinder heads 6a and 7a.

  With the above-described configuration, a part of the cooling water circulation water channel is a water channel 156 configured integrally with the right crankcase 11 and the inner transmission cover 15, so that this water channel 156 is exposed to the outside. Therefore, it is possible to prevent the pipe from interfering with the attachment or detachment of parts around the engine as in the prior art.

  Further, since the water channel 156 is not exposed to the outside, the aesthetic appearance of the entire motorcycle 1 is improved. In particular, in the type in which the engine of an American type or the like is exposed to the outside, such as the motorcycle 1 according to the present embodiment, the number of pipes that are exposed to the outside can be reduced. It is remarkable.

  Further, as in the present embodiment, a general motorcycle has a side stand 5 provided on the left side of the vehicle body (see FIG. 1), and therefore, when the vehicle body is supported by the side stand 5 in a standing state. Since the vehicle body is slightly tilted to the left side, the right side of the vehicle body is more likely to be noticed than the left side of the vehicle body. In the case where the water pump 127 is arranged on the right side of the vehicle body as in the motorcycle 1 according to the present embodiment, the pipe connected to the water pump 127 is arranged on the right side of the vehicle body, It is desired to reduce this pipe. Therefore, in such a case, the effect of the engine cooling structure according to the present invention in which the number of pipes for flowing cooling water exposed to the outside can be reduced more significantly.

  Further, by providing the grooves 151 and 154 along the joint surface of the right crankcase 11 and the inner mission cover 15, the length of the water channel 156 formed integrally with the right crankcase 11 and the inner mission cover 15 is sufficient. Therefore, the number of pipes exposed to the outside can be further reduced.

  In the embodiment of the present invention, since the transmission case is substantially configured as a part of the right crankcase 11, a crank chamber and a transmission chamber are formed in the right crankcase 11. A relatively large surplus space exists between the crank chamber 20 of the case 11 and the transmission chamber 21. By providing a groove 154 in such a surplus space portion of the right crankcase 11, a crank by integrally molding the water channel The enlargement of the case 8 can be suppressed.

  Further, the pump casing 127a of the water pump 127 is formed integrally with the right crankcase 11 and the inner transmission cover 15, so that the crankcase (transmission case) and the water pump are provided separately. Thus, the engine unit including the transmission and the water pump can be reduced in size. As another engine cooling structure, for example, a part of a water pump casing is integrally formed with a crankcase or a transmission case (hereinafter referred to as a crankcase), and the water pump is configured inseparably from the crankcase or the like. A part of the cooling water passage (water channel) connected to the water pump may be formed in a crankcase or the like, but the crankcase or the like is almost always cast. It is difficult to increase the length of the water channel that is integrally formed with the water channel. Moreover, even if the water channel integrally formed in the crankcase or the like is lengthened, the pipe shape protruding to the outside is formed, and the demand for reducing the number of pipes cannot be satisfied. However, according to the engine cooling structure according to the embodiment of the present invention, since the groove is formed along the joint portion between the right crankcase 11 and the inner transmission cover 15, the length of the water channel is sufficiently secured. However, the pipe-like portion exposed to the outside can be reduced.

Also, it has dealt with the integrally molded with the structures of the pump casing 127a of the water pump 127 on the right crankcase 11 and the inner transmission cover 15, a portion of the waterway crankcase and the cover and the transmission case and the cover integral with cooling water As long as it is a molded configuration, a water pump may be provided separately from the crankcase and cover and the transmission case and cover.

  Further, the engine cooling structure according to the present invention is not limited to the one mounted on an American type motorcycle, and can be applied to a road racer type and other types of motorcycles. Further, the present invention is not limited to motorcycles, and can be applied to engines such as four-wheel buggies and automobiles.

  Furthermore, the above-described embodiment is an embodiment, and various modifications can be made without departing from the spirit of the present invention, and the present invention is not limited to the above-described embodiment.

  According to the engine cooling structure of the present invention, a part of the cooling water channel is not exposed to the outside, and it is possible to easily attach or remove parts around the engine as compared with the conventional one, and to provide a motorcycle. The effect of improving the overall aesthetic appearance can be expected, and it is useful as an engine cooling structure for cooling the cylinder of a motorcycle engine.

1 is a left side view of a motorcycle equipped with an engine cooling structure according to an embodiment of the present invention. It is a partial section left side view of an engine concerning an embodiment of the invention. It is a partial section right side view of an engine concerning an embodiment of the invention. It is a disassembled perspective view which shows the main housing components of the engine except a cylinder. It is a left view of the inner side mission cover which concerns on embodiment of this invention. It is a right view of the right crankcase which concerns on embodiment of this invention. FIG. 3 is a VII-VII cross-sectional view of the engine shown in FIG. 2. It is VIII-VIII sectional drawing of the engine E shown in FIG.

Explanation of symbols

1 Motorcycle 2 Front Wheel 3 Rear Wheel (Drive Wheel)
4 Frame 5 Side stand 6, 7 Cylinder 6a, 7a Cylinder head 8 Crank case 9 Oil pan 10 Left crank case 11 Right crank case 12 Inner clutch cover 13 Outer clutch cover 14 Cam cover 15 Inner mission cover 17 Outer mission cover 20 Crank chamber 21 Transmission Chamber 22 Output shaft chamber 23 Separator chamber 24 Clutch chamber 24a Oil reservoir 25 Cam chamber 26 Oil storage chamber 30 Crankshaft 33 Connecting rod 34 Piston 41 Main shaft 42 Countershaft 44 Partition 45 Clutch 51 Transmission 53 Output shaft 70 Partition 71 Oil pump 85 Pump shaft 126 Drive gear 127 Water pump 127a Pump casing 127b Suction port 12 8 Rotor 129 Pump shaft 130 Bearing 140 Radiator 141 Pipes 150 and 153 Recesses 151 and 154 Grooves 152 and 155 Joint surface 156 Water channels 157 to 161 Pipe 162 Thermostat 163 Pipe

Claims (1)

A water pump for discharging cooling water for cooling a cylinder of a motorcycle engine;
A water channel for sending cooling water discharged from the water pump to the cylinder ;
A crankcase forming a crank chamber and a transmission chamber;
A mission cover that covers the outside of the crankcase ,
The opposing portions of the crankcase and the mission cover are each recessed in a concave shape, and the circumferential joining end surface of the crankcase is joined to the circumferential joining end surface of the mission cover,
The crankcase and the mission cover are each provided with a groove on the inner peripheral side along the joint end surface, and at least a part of the water channel is formed by joining the joint end surfaces to each other so that both grooves coincide with each other. Formed,
The water pump has a pump casing formed integrally with the crankcase and the transmission cover, and the groove of the crankcase is provided between the crank chamber and the transmission chamber. Construction.

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