JP2005120922A - Drive mechanism and saddle type vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive mechanism having structural components including a driving pulley and a driving sprocket supported at the ends of a crank shaft while keeping the axial sizes of the ends of the crank shaft more equal with one another. <P>SOLUTION: An internal combustion engine 21 has a crank shaft 30 supported on a crank case 26 by a bearing 29 for supporting the driving pulley 44, the endless transmission belt driving sprocket 67 supported by the crank shaft 30, a starter clutch 74 supported by the crank shaft 30, and a driving gear 88 supported by the crank shaft 30 for driving a lubricating oil pump 87. The driving pulley 44 and the driving sprocket 67 are supported at one end 37 of the crank shaft 30. The starter clutch 74 and the driving gear 88 are supported at the other end 38 of the crank shaft 30. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a drive device including a four-cycle internal combustion engine that is a drive source in a vehicle or the like, a belt winding device that interlocks and connects a driven side to the internal combustion engine, and a saddle type that includes the drive device. It relates to vehicles.

  Conventionally, there is a driving device in a saddle-ride type vehicle disclosed in Patent Document 1 below. According to this publication, the driving device includes a four-cycle internal combustion engine that is a driving source for traveling, and a belt winding device that can transmit a driving force output from the internal combustion engine to a rear wheel that is a driven side. And.

  The internal combustion engine is supported by the crankshaft, which is supported by a crankshaft that supports a drive pulley of the belt wrapping device with a middle portion in the axial direction supported by a bearing by a bearing so as to be rotatable around a certain axis. A chain-wound drive sprocket capable of transmitting power to the camshaft of the valve mechanism, a starter motor supported by the crankshaft to enable cranking of the crankshaft, and supported by the crankshaft for lubrication And a drive gear capable of transmitting a driving force to the oil pump.

  In the above case, the driving pulley is supported on one end of the crankshaft, and the driving sprocket, the starting motor, and the driving gear are supported on the other end.

  When starting the internal combustion engine in order to drive the vehicle, first, the starter motor is driven to perform cranking. Then, the drive sprocket is interlocked with the crankshaft, that is, the valve operating mechanism is interlocked to suck and exhaust the internal combustion engine. In addition, an oil pump is interlocked with the crankshaft via the drive gear to lubricate each lubricated portion. As a result, the driving of the internal combustion engine is started and this driving is continued, and a driving force is output from the crankshaft. Then, this driving force is transmitted to the rear wheels via the belt winding device, so that the vehicle can travel.

JP 2000-203483 A

  By the way, as described above, at one end of the crankshaft, only the driving pulley of the driving pulley, the driving sprocket, the starting device, and the driving gear, which are components of the driving device, is supported, and at the other end, Since the drive sprocket, the starter, and the drive gear are intensively supported, the other end portion of the crankshaft tends to be longer than the one end portion.

  For this reason, when the drive device is to be mounted on, for example, a saddle-ride type vehicle, the crankcase and the cylinder protruding from the crankcase are connected to the width of the vehicle body in view of the left-right weight balance and the appearance of the vehicle. If it is located near the center of the direction, the other side portion of the drive device having the other end portion of the crankshaft is larger on the outer side than the one side portion of the drive device having the one end portion of the crankshaft. This tends to protrude, which is not preferable in terms of handling and appearance of the vehicle.

  Therefore, it is conceivable to distribute and arrange these components at the respective end portions so that many of the component components are not intensively supported at one end portion of the crankshaft as described above. However, if this is simply done, firstly, a drive pulley that should be isolated from the lubricating oil to prevent slippage due to contact with the lubricating oil, and a crankshaft that requires lubrication with the lubricating oil. It may be difficult to structurally separate the midway portion, the drive sprocket, and the drive gear from each other. Second, in particular, the degree of freedom of the arrangement of the oil pump is narrowed by other components other than the oil pump, and it may be difficult to arrange the oil pump at a desired position.

  The present invention has been made paying attention to the above situation, and the object of the present invention is to provide a driving device in which components such as a driving pulley and a driving sprocket are supported at each end of a crankshaft. The axial dimension of each end of the crankshaft is made more uniform to each other.

  Another object of the present invention is to provide components that should be isolated from the lubricating oil and components that require lubrication, even when the dimensions of the ends of the crankshaft are made more equal to each other as described above. It is possible to easily separate the oil pumps structurally from each other, and in particular, to easily place the oil pump among the components at a desired position.

The invention of claim 1 includes a four-cycle internal combustion engine 21 that is a drive source, and a belt winding device 22 that enables transmission of the driving force output from the internal combustion engine 21 to the driven side. The crankshaft 30 is supported on the crankcase 26 by a bearing 29 so as to be rotatable around a certain axis 27 and supports the drive pulley 44 of the belt winding device 22, and the valve operating by being supported by the crankshaft 30. A drive sprocket 67 for winding an endless transmission band capable of transmitting power to the camshaft 65 of the mechanism 64, and power transmission from the starter motor 72 to the crankshaft 30 supported by the crankshaft 30 can be connected and disconnected. And a drive gear 88 supported by the crankshaft 30 and capable of transmitting a driving force to the lubricating oil pump 87.
The drive pulley 44 and the drive sprocket 67 are supported on one end portion 37 of the crankshaft 30, and the starter clutch 74 and the drive gear 88 are supported on the other end portion 38 of the crankshaft 30.

  According to a second aspect of the invention, in addition to the first aspect of the invention, the drive sprocket 67 is positioned closer to the bearing 29 than the drive pulley 44.

  According to a third aspect of the present invention, in addition to the first or second aspect of the present invention, the starter clutch 74 is supported on the crankshaft 30 so as to be free to rotate about the axis 27 of the crankshaft 30. A starter gear 77 capable of inputting a driving force from the starter motor 73, and supported by the crankshaft 30 so as to rotate together with the crankshaft 30, allows only the input of the driving force from the starter gear 77, and A clutch main body 78 having a smaller outer diameter than the starter gear 77 is provided, and the clutch main body 78 is positioned closer to the drive gear 88 than the starter gear 77 is.

  According to a fourth aspect of the invention, in addition to any one of the first to third aspects of the invention, the drive gear 88 is positioned closer to the bearing 29 than the starter clutch 74.

  According to a fifth aspect of the present invention, in addition to any one of the first to fourth aspects of the present invention, the crankcase 26 protrudes from the side wall 40 of the crankcase 26 toward the other end 38 in the axial direction of the crankshaft 30. A housing 52 that accommodates the other end 38 of the shaft 30 is provided, and a cover body 59 that is fitted into the housing 52 and is detachably fixed to the housing 52 is provided. A space 61 that is partitioned by the cover body 59. The starter clutch 74 and the drive gear 88 are accommodated in the space 61 so that they can be lubricated.

  According to a sixth aspect of the present invention, in addition to the fifth aspect of the invention, the other end of the crankshaft 30 is provided by a fastener 80 screwed to the crankshaft 30 by twisting around the axis 27 of the crankshaft 30. 38, the starter clutch 74 is supported, and an opening 98 that allows the twisting tool 97 of the fastener 80 to be inserted / extracted only in a part of the circumferential direction of the housing 52 corresponding to the radially outward direction of the fastener 80. The opening 98 is closed so as to be openable and closable.

  The invention of claim 7 relates to the saddle riding type vehicle 1 on which the driving device 18 according to any one of claims 1 to 6 is mounted as a driving source for traveling.

  In this section, the reference numerals appended to the above terms are not intended to limit the technical scope of the present invention to the contents of the “Examples” section described later.

  The effects of the present invention are as follows.

The invention of claim 1 includes a four-cycle internal combustion engine as a drive source and a belt winding device that enables transmission of the driving force output from the internal combustion engine to the driven side. A crankshaft supported on the crankcase by a bearing so as to be rotatable around and supporting the drive pulley of the belt winding device, and supported by the crankshaft and capable of transmitting power to the camshaft of the valve mechanism. A drive sprocket for winding an endless transmission band, a starter clutch supported by the crankshaft to connect and disconnect power transmission from the starter motor to the crankshaft, and a lubricating oil pump supported by the crankshaft In the drive device provided with a drive gear that can transmit the drive force to
The drive pulley and the drive sprocket are supported at one end of the crankshaft, and the starter clutch and the drive gear are supported at the other end of the crankshaft.

  Here, regarding the axial dimensions of the drive pulley, drive sprocket, starter clutch, and drive gear, the dimensions of the drive pulley and starter clutch are generally the same as the dimensions of the drive sprocket and drive gear. Each is considerably larger.

  Therefore, as described above, the drive pulley and the drive sprocket are supported on one end portion of the crankshaft, and the starter clutch and the drive gear are supported on the other end portion. In combination, each end of the crankshaft is distributed and arranged at each end of the crankshaft. For this reason, in the driving device for supporting components such as a drive pulley and a drive sprocket at each end of the crankshaft, each end of the crankshaft The axial dimensions of the parts can be made more uniform with each other.

  Therefore, when the drive device is mounted on, for example, a saddle-ride type vehicle, the crankcase and the cylinder projecting from the crankcase are centered in the width direction of the vehicle body in view of the left-right weight balance and the appearance of the vehicle. When positioned in the vicinity, it is possible to prevent one of the side portions of the drive device having the end portions of the crankshaft from projecting outward to a larger extent. It is beneficial in terms of appearance and appearance.

  According to a second aspect of the present invention, the drive sprocket is positioned closer to the bearing than the drive pulley.

  Therefore, among the bearing, the driving pulley, the driving sprocket, the starter clutch, and the driving gear, the bearing, the driving sprocket, the starter clutch, and the driving gear are arranged adjacent to each other. It becomes easy to make it isolate | separate from and to accommodate in the space which can be lubricated with lubricating oil.

  Therefore, the drive pulley that should be isolated from the lubricant to prevent slippage due to contact with the lubricant, and the bearing, drive sprocket, starter clutch, and drive gear that require lubrication with the lubricant are structurally structured. Can be easily separated from each other.

  According to a third aspect of the present invention, there is provided a starter gear that is supported on the crankshaft so that the starter clutch can be freely rotated about the axis of the crankshaft and that can input a driving force from the starting motor. A clutch body supported by the crankshaft so as to rotate together with the crankshaft, enabling only the input of driving force from the starter gear, and having a smaller outer diameter than the starter gear. It is located closer to the drive gear than the gear.

  For this reason, as described above, the clutch body having a small outer diameter and the drive gear capable of transmitting the driving force to the oil pump are adjacent to each other. Therefore, the oil pump, the oil pump and the drive gear are At least a part of the interlocking means can be arranged using a space radially outward of the clutch body.

  Therefore, even if the starter clutch and the drive gear are arranged compactly, the oil pump can be arranged at a desired position.

  According to a fourth aspect of the present invention, the drive gear is positioned closer to the bearing than the starter clutch.

  Here, as described above, when the drive gear is positioned closer to the bearing than the starter clutch, the oil pump coupled to the drive gear is closer to the bearing side. And since this bearing is supported by the crankcase, the said oil pump will approach this crankcase. In general, since the lubricating oil passage for the lubricating oil discharged from the oil pump is formed in the crankcase, the oil pump can be communicated with the lubricating oil passage in terms of structure.

  According to a fifth aspect of the present invention, there is provided a housing that protrudes from the side wall of the crankcase toward the other end in the axial direction of the crankshaft and accommodates the other end of the crankshaft, and is fitted into the housing. A cover body detachably fixed to the housing is provided, a space defined by the cover body is formed, and the starter clutch and the drive gear are accommodated in the space so that they can be lubricated.

  Here, the shape of the housing is required to have a certain size in order to sufficiently reinforce the crankcase or accommodate the other end portion of the crankshaft. Therefore, as described above, the cover body is fitted and fixed to the housing, and for this reason, the insertion dimension of the cover body to the housing is set to a predetermined dimension while the housing is kept at a certain size. If set, the space can be minimized. Therefore, it is possible to prevent the lubricating oil from staying more than necessary in this space and to prevent unnecessary rotation of the lubricating oil.

  According to a sixth aspect of the present invention, the starter clutch is supported on the other end of the crankshaft by a fastener that is screwed to the crankshaft by twisting about the axis of the crankshaft, and the radial direction of the fastener An opening for allowing insertion and removal of the tool for twisting the fastener is formed only in a part of the housing in the circumferential direction corresponding to the outside, and the opening is closed so as to be opened and closed.

  For this reason, as described above, since the opening is formed only in a part of the housing in the circumferential direction, the strength of the housing is prevented from being reduced, and the crankcase is effectively reinforced by the housing. And while this effect is maintained, the operation to the fastener can be easily performed by using the opening.

  According to a seventh aspect of the present invention, the driving device is mounted on a saddle riding type vehicle as a driving source for traveling.

  For this reason, in the vehicle, any one of the effects resulting from claims 1-6 is produced, and particularly beneficial in terms of appearance of the vehicle handling, which is the effect of claim 1. It is.

  In the drive device according to the present invention, in the drive device that supports components such as a drive pulley and a drive sprocket at each end portion of the crankshaft, the axial dimensions of each end portion of the crankshaft are made more uniform to each other. In order to realize the object, the best mode for carrying out the present invention is as follows.

  That is, the drive device includes a four-cycle internal combustion engine that is a drive source of a vehicle or the like, and a belt winding device that can transmit the drive force output from the internal combustion engine to the driven side.

  The internal combustion engine is supported by the crankshaft, which is supported by a crankshaft that supports a drive pulley of the belt wrapping device with a middle portion in the axial direction supported by a bearing by a bearing so as to be rotatable around a certain axis. A drive sprocket for winding an endless transmission band that can transmit power to the camshaft of the valve mechanism, and a starter that is supported by the crankshaft and that can connect and disconnect power transmission from the starter motor to the crankshaft A clutch and a drive gear supported by the crankshaft and capable of transmitting a driving force to the lubricating oil pump are provided.

  The drive pulley and the drive sprocket are supported at one end of the crankshaft with the midway portion of the crankshaft as a reference, and the starter clutch and the drive gear are supported at the other end of the crankshaft.

  In order to explain the present invention in more detail, the embodiment will be described with reference to the accompanying drawings.

  In FIG. 1, reference numeral 1 denotes a scooter type motorcycle which is an example of a saddle-type vehicle, and an arrow Fr indicates the front in the traveling direction of the vehicle 1. The left and right described below refer to the width direction of the vehicle body 2 of the vehicle 1 toward the front.

  The vehicle body 2 includes a vehicle body frame 3 that constitutes a skeleton of the vehicle body 2, a front fork 4 that is slidably supported on the front end portion of the vehicle body frame 3, and a front frame 4 that is supported on the lower end portion of the front fork 4. The steering wheel 6 that is supported on the upper end of the front fork 4 and the steering wheel 6 that extends in the longitudinal direction (front-rear direction) of the vehicle body 2 so that the rear side of the front side can swing up and down. A rear arm 9 that is pivotally supported by a pivot shaft 8 at a middle portion in the front-rear direction of the body frame 3, a rear wheel 10 that is supported by a swinging end portion of the rear arm 9, a rear end portion of the body frame 3, and the above-mentioned A hydraulic cylinder type shock absorber 11 installed on the swinging end portion of the rear arm 9, a seat 12 supported on the upper surface of the rear portion of the vehicle body frame 3, and the longitudinal direction of the vehicle body 2 on the front side of the seat 12 Midway top And a foot rest 13 to be formed.

  The front and rear wheels 5, 10 are positioned on the center 16 in the width direction of the vehicle body 2 and can be grounded on the road surface 17. The rear arm 9 outputs a driving force to the rear wheel 10 to drive the vehicle 1. A drive device 18 that enables traveling driving is configured, that is, the vehicle 1 is provided with a swing type drive unit.

  1-7, the drive unit 18 can transmit the driving force output from the internal combustion engine 21 to the rear wheel 10 on the driven side, and the four-cycle internal combustion engine 21 for driving the vehicle 1. A belt winding device 22, a centrifugal clutch 23, and a gear type reduction device 24 are provided.

  The internal combustion engine 21 has an aluminum cast crankcase 26 pivotally supported on the vehicle body frame 3 by the pivot shaft 8 and a shaft center 27 extending in the width direction of the vehicle body 2 so as to be rotatable around the shaft center 27. The intermediate portion 28 is supported by the crankcase 26 by a pair of left and right bearings 29, 29, and protrudes forward from the crankcase 26 in a substantially horizontal direction. A cylinder 32 having an axis 31 orthogonal to the axis 27, a piston 34 slidably fitted in a cylinder hole 33 in the cylinder 32, a midway portion 28 of the crankshaft 30, and the piston 34. Are connected to each other. A space surrounded by the inner surface of the cylinder hole 33 and the piston 34 at the protruding portion of the cylinder 32 is a combustion chamber 36. The axial center 31 of the cylinder 32 is arranged in the vicinity of the center 16 in the width direction of the vehicle body 2.

  The crankshaft 30 has one end (left end) 37 and the other end (right end) 38 in the axial direction with respect to the midway portion 28 as a crank main shaft, both of which are free ends. A midway portion 28 of the crankshaft 30 is a journal portion formed at each of the base portions of the one end portion 37 and the other end portion 38, a pair of left and right crank webs fixed to the respective base portions, and spanning the crank webs. And a crank pin connected to the connecting rod 35.

  Each journal portion of the intermediate portion 28 of the crankshaft 30 is supported by bearings 29 by one side wall (left side wall) 39 and the other side wall (right side wall) 40 in the axial direction of the crankshaft 30. A crank chamber 41 is formed between one side wall 39 and the other side wall 40 of the crankcase 26, and a crank web of the crankshaft 30 and a crank pin are accommodated in the crank chamber 41.

  The belt wrapping device 22 is an automatic transmission, and the belt wrapping device 22 includes a transmission case 43 that constitutes an outer shell thereof and extends rearward from one side wall 39 of the crankcase 26; A drive pulley 44 housed in the front part of the transmission case 43 and supported by one end 37 of the crankshaft 30, and a transmission pulley 43 housed in the rear part of the transmission case 43 and behind the drive pulley 44. A driven pulley 45 that is rotatably supported by the centrifugal clutch 23 and linked to the rear wheel 10 via the centrifugal clutch 23, and a V-belt 46 wound around the driving pulley 44 and the driven pulley 45. The hanging device 22 is a mechanism in which the reduction ratio decreases as the crankshaft 30 rotates at a high speed.

  A housing 49 is provided to cover the outer side surface of the one side wall 39 of the crankcase 26 and the outer side surface of the cylinder 32 connected to the one side wall 39 and to penetrate the one end 37 of the crankshaft 30. A through portion of one end 37 of the crankshaft 30 in the housing 49 is sealed by a seal body 50, and is surrounded by the outer surface of one side wall 39 of the crankcase 26, the outer surface of the cylinder 32, and the housing 49. In this portion, a side space 51 is formed that is isolated from the inside of the transmission case 43.

  Another housing 52 that protrudes from the other side wall 40 of the crankcase 26 toward the other end 38 in the axial direction of the crankshaft 30 is provided. The other end 38 of the crankshaft 30 is accommodated entirely. The housing 52 constitutes a housing body 53 integrally projecting from one side wall 39 of the crankcase 26 and a projecting end portion of the housing 52, and is attached to and detached from the projecting end portion of the housing body 53 by a fastener 54. And a resin-made protruding portion 55 which can be fixed.

  A cover body 59 made of cast aluminum is provided in the housing 52 so as to be removably fitted from the protruding end side. The other end portion 38 of the crankshaft 30 passes through the cover body 59, and the cover body 59 is detachably fixed to a midway portion in the axial direction of the housing main body 53 of the housing 52 by a fastener 58. Yes. The portion of the cover body 59 that penetrates the other end 38 of the crankshaft 30 is sealed by a seal body 60, and is surrounded by the other side wall 40 of the crankcase 26, the housing body 53 of the housing 52, and the cover body 59. The other side space 61 isolated from the outer side of the housing 52 is formed.

  The internal combustion engine 21 includes a suction and exhaust valve (not shown) that opens and closes the combustion chamber 36 of the internal combustion engine 21 toward the outside, and a valve operating mechanism 64 that operates the valves to open and close. The valve mechanism 64 includes a camshaft 65 supported on the protruding end of the cylinder 32 so as to be cam-engaged with the intake and exhaust valves, and a chain winding that interlocks the camshaft 65 with the crankshaft 30. Means 66.

  The chain winding means 66 includes a drive sprocket 67 supported by one end 37 of the crankshaft 30 and capable of transmitting power to the camshaft 65, a driven sprocket 68 supported by the camshaft 65, A chain 69 which is an example of an endless transmission band wound around the drive sprocket 67 and the driven sprocket 68 is provided. The drive sprocket 67 of the chain winding means 66 is positioned closer to the middle portion 28 of the crankshaft 30 than the drive pulley 44 and is accommodated in the one side space 51. The endless transmission band may be a timing belt.

  The internal combustion engine 21 includes a starter 72 that cranks the crankshaft 30 and enables the internal combustion engine 21 to start. The starter 72 is connected to the starter motor 73 supported on the upper part of the crankcase 26 and the power transmission from the starter motor 73 to the crankshaft 30 supported by the other end 38 of the crankshaft 30. A starter clutch 74 that can be disconnected and a gear set 75 that interlocks the starter clutch 74 to the starter motor 73 are provided.

  The starter clutch 74 is supported on the other end 38 of the crankshaft 30 so as to be free to rotate about the axis 27 of the crankshaft 30, and the driving force from the starting motor 73 is transmitted via the gear set 75. A starter gear 77 that can be input, and a clutch main body 78 that is supported by the other end portion 38 of the crankshaft 30 so as to rotate together with the crankshaft 30 and that allows only input of driving force from the starter gear 77. The clutch body 78 has an outer diameter smaller than that of the starter gear 77.

  The clutch main body 78 of the starter clutch 74 and the drive gear 88 are fixed to each other in the axial direction of the other end portion 38 of the crankshaft 30 by a fastener 80. The fastener 80 is fitted in the middle portion of the other end portion 38 and a male screw 81 formed around the shaft center 27 and in the middle portion of the other end portion 38. And a nut body 82 that is screwed to the male screw 81 of the crankshaft 30 by turning around.

  The internal combustion engine 21 includes a lubrication device 85 that can lubricate each lubricated portion such as the bearing 29 with lubricating oil. The lubrication device 85 is supported on the lower surface of the crankcase 26 and stores an oil pan 86 that accumulates lubricating oil in an internal space thereof. The lubrication device 85 is attached to a lower portion of the crankcase 26 and removes the lubricating oil in the oil pan 86 from the oil pan 86. An oil pump 87 that can be supplied to each lubricated part, a drive gear 88 that is supported by the other end 38 of the crankshaft 30 and that can transmit a driving force to the oil pump 87, and an input of the oil pump 87 A driven gear 89 that is attached to the shaft and meshes with the drive gear 88 is provided. The drive gear 88 has a smaller outer diameter than the clutch body 78 of the starter clutch 74. The lower end portions of the one side space 51 and the other side space 61 are communicated with the oil pan 86.

  The clutch body 78 is positioned closer to the drive gear 88 than the starter gear 77 of the starter clutch 74. The drive gear 88 is positioned closer to the middle portion 28 of the crankshaft 30 than the starter clutch 74 and is directly attached to the other side wall 40 of the crankcase 26. The starter clutch 74, the drive gear 88, and the driven gear 89 are accommodated in the other side space 61.

  The crank chamber 41, the one side space 51, and the other side space 61 communicate with each other through bearings 29 that support the midway portion 28 of the crankshaft 30, and a wet space in which the lubricating oil is accommodated. Thus, the bearings 29 are lubricated, the drive sprocket 67 of the chain winding means 66 is lubricated in the one side space 51, and the starter clutch 74, the drive gear 88, and the driven gear 89 are Lubrication is performed in the other side space 61.

  A flywheel magneto 91 is detachably fixed to the end of the other end 38 of the crankshaft 30 by a fastener 92, and a fan 93 is detachably fixed to the flywheel magneto 91 by a fastener 94. Each is supported. Further, a radiator 95 that supports cooling water for cooling the cylinder 32 by the wind of the fan 93 is supported on the protruding end of the other housing 52.

  When starting the internal combustion engine 21 in order to drive the vehicle 1, first, the starter motor 73 is driven to perform cranking. Then, the drive sprocket 67 is interlocked with the crankshaft 30, that is, the valve mechanism 64 is interlocked to suck and exhaust the cylinder 32 of the internal combustion engine 21. Further, the oil pump 87 is interlocked with the crankshaft 30 via the drive gear 88 to lubricate each lubricated portion. As a result, the driving of the internal combustion engine 21 is started, this driving is continued, and a driving force is output from the crankshaft 30. Then, this driving force is transmitted to the rear wheel 10 via the belt winding device 22, the centrifugal clutch 23, and the speed reduction device 24, so that the vehicle 1 can run.

  4 and 8, the twisting tool 97 of the nut body 82 of the fastener 80 can be inserted / extracted only in a part of the circumferential direction of the housing 52 corresponding to the radially outer side of the nut body 82 of the fastener 80. In addition, an opening 98 is formed around the axis 27 of the crankshaft 30 so that the twisting tool 97 can be rotated by a predetermined angle. Moreover, this opening 98 is closed so that opening and closing is possible.

  More specifically, a part of the mating surface between the protruding end portion of the housing main body 53 of the other housing 52 and the end portion of the protruding portion 55 on the housing main body 53 side is relative to the axis 27 of the crankshaft 30. Inclined toward the crankcase 26 side. The inclined portion of the mating surface forms the opening 98 at the protruding end portion of the housing body 53 of the other housing 52, and the opening 98 is closed by the protruding portion 55 so as to be opened and closed.

  In FIG. 8, the protrusions 55, the cover body 59, the flywheel magneto 91, the fan 93, and the radiator from the other end portion 38 of the crankshaft 30 by the loosening operation to the respective fasteners 54, 58, 92, 94. When 95 is removed, the opening 98 is opened. Therefore, if the nut body 82 of the fastener 80 is loosened from the outside in the radial direction by the twisting tool 97 through the opening 98, the starter clutch 74 and the drive gear from the other end 38 of the crankshaft 30. 88 can be separated. The assembling work of each component may be performed in the reverse order of the above.

  According to the above configuration, the drive pulley 44 and the drive sprocket 67 are supported by the one end 37 of the crankshaft 30 with the middle portion 28 of the crankshaft 30 as a reference, and the other end 38 of the crankshaft 30 The starter clutch 74 and the drive gear 88 are supported.

  Here, regarding the axial dimensions of the drive pulley 44, the drive sprocket 67, the starter clutch 74, and the drive gear 88, the dimensions of the drive pulley 44 and the starter clutch 74 are generally the same as those of the drive sprocket 67. Compared with the dimensions of the drive gear 88, each is considerably larger.

  Therefore, as described above, the drive pulley 44 and the drive sprocket 67 are supported by the one end portion 37 of the crankshaft 30, and the starter clutch 74 and the drive gear 88 are supported by the other end portion 38. The large and small ones are combined and distributed at the respective ends of the crankshaft 30. For this reason, the axial middle portion of the crankshaft 30 is supported by the bearing 29 on the crankcase 26, and In the drive device 18 that supports the components such as the drive pulley 44 and the drive sprocket 67 at each end of the crankshaft 30, the axial dimensions of the end portions 37 and 38 of the crankshaft 30 can be made more equal to each other. it can.

  Therefore, when the drive device 18 is mounted on, for example, the saddle riding type vehicle 1, the crankcase 26 and the cylinder 32 protruding from the crankcase 26 are provided in view of the left-right weight balance and appearance of the vehicle 1. When the vehicle body 2 is positioned in the vicinity of the center 16 in the width direction of the vehicle body 2, one of the side portions of the drive device 18 having the end portions 37 and 38 of the crankshaft 30 protrudes outward more greatly. This is beneficial in terms of the handling and appearance of the vehicle 1.

  Further, as described above, the drive sprocket 67 is positioned closer to the midway portion 28 of the crankshaft 30 and the bearing 29 than the drive pulley 44.

  Therefore, of the crankshaft 30 midway portion 28, bearing 29, drive pulley 44, drive sprocket 67, starter clutch 74, and drive gear 88, the crankshaft 30 midway portion 28, bearing 29, drive sprocket 67, Since the starter clutch 74 and the drive gear 88 are arranged adjacent to each other, it is easy to isolate them from the drive pulley 44 and accommodate them in a space that can be lubricated with lubricating oil.

  Therefore, the drive pulley 44 that should be isolated from the lubricant to prevent slippage due to contact with the lubricant, the intermediate portion 28 of the crankshaft 30 that requires lubrication with the lubricant, the bearing 29, and the drive sprocket 67. The starter clutch 74 and the drive gear 88 can be easily separated from each other structurally.

  Further, as described above, the starter clutch 74 is supported by the crankshaft 30 so as to be free to rotate about the axis 27 of the crankshaft 30 and can input the driving force from the starter motor 73. A clutch body 78 is supported by the crankshaft 30 so as to rotate together with the gear 77 and the crankshaft 30, and can only input a driving force from the starter gear 77, and has a smaller outer diameter than the starter gear 77. The clutch main body 78 is positioned closer to the drive gear 88 than the starter gear 77 is.

  Therefore, as described above, the clutch body 78 having a small outer diameter and the drive gear 88 capable of transmitting the driving force to the oil pump 87 are adjacent to each other. At least a part of the driven gear 89 that is an interlocking means of the drive gear 88 and the drive gear 88 can be arranged by using a space radially outward of the clutch body 78.

  Therefore, even if the starter clutch 74 and the drive gear 88 are arranged compactly, the oil pump 87 can be arranged at a desired position.

  Further, as described above, the drive gear 88 is positioned closer to the midway portion 28 of the crankshaft 60 and the bearing 29 than the starter clutch 74.

  Here, as described above, when the drive gear 88 is positioned closer to the midway portion 28 of the crankshaft 30 and the bearing 29 than the starter clutch 74, the oil pump 87 linked to the drive gear 88 is linked to each other. The intermediate part 28 and the bearing 29 side are closer to each other. Since the midway portion 28 and the bearing 29 are supported by the crankcase 26, the oil pump 87 approaches the crankcase 26. In general, the crankcase 26 is formed with a lubricating oil passage for the lubricating oil discharged from the oil pump 87, so that the oil pump 87 can be easily communicated with the lubricating oil passage. .

  Further, as described above, the housing 52 that protrudes from the other side wall 40 of the crankcase 26 toward the other end 38 in the axial direction of the crankshaft 30 is provided to accommodate the other end 38 of the crankshaft 30. A cover body 59 that is removably fitted into the housing 52 and is detachably fixed to the housing 52 is provided, and is surrounded by the other side wall 40 of the crankcase 26, the other housing 52, and the cover body 59. In the partitioned portion, the other side space 61 isolated from the outside of the housing 52 is formed, and the starter clutch 74 and the drive gear 88 are accommodated in the other side space 61 so that they can be lubricated. .

  Here, the shape of the other housing 52 is required to have a certain size in order to sufficiently reinforce the crankcase 26 and accommodate the other end portion 38 of the crankshaft 30. Therefore, as described above, the cover body 59 is fitted and fixed to the other housing 52, and therefore, the cover to the housing 52 is maintained while the other housing 52 is kept at a certain size. If the fitting dimension of the body 59 is set to a predetermined dimension, the other side space 61 can be minimized. Therefore, it is possible to prevent the lubricating oil from staying in the other side space 61 in excess of the necessary amount and useless rotation of the lubricating oil.

  Further, as described above, the starter clutch 74 and the drive gear 88 are connected to the other end portion 38 of the crankshaft 30 by the fastener 80 screwed to the crankshaft 30 by twisting around the axis 27 of the crankshaft 30. And an opening 98 that allows the twisting tool 97 of the fastener 80 to be inserted / extracted only in a part of the housing 52 in the circumferential direction corresponding to the outer side of the fastener 80 in the radial direction. The opening 98 is closed so that it can be opened and closed.

  For this reason, as described above, since the opening 98 is formed only in a part of the circumferential direction of the housing 52, the strength of the housing 52 is prevented from being lowered, and the reinforcement of the crankcase 26 by the housing 52 is effective. To be done. Then, while maintaining this effect, the operation of the fastener 80 when the starter clutch 74 and the drive gear 88 are detached can be easily performed by using the opening 98.

  In FIG. 4, one end portion 37 of the crankshaft 30 has a large-diameter portion adjacent to the midway portion 28 and a small-diameter portion that supports the drive pulley 44, from these large-diameter portion to the small-diameter portion. A stepped surface orthogonal to the axis 27 is formed at the transition portion of the first and second circular plates, and an annular plate washer 100 is interposed between the drive pulley 44 and the stepped surface.

  Conventionally, an arc recess (R) is formed between the small-diameter portion and the step surface. However, in this case, a substantial contact area between the step surface and the washer 100 is reduced, and the washer 100 is driven by the drive. There is a risk of deformation due to an external force from the pulley 44.

  Therefore, an annular groove is formed on the outer peripheral surface of the small portion of the small diameter portion adjacent to the step surface to increase the substantial contact area, and the washer 100 is made of a highly rigid SK material. For example, the inner peripheral portion of the washer 100 is prevented from being fitted into the groove.

  Although the above is based on the illustrated example, the vehicle 1 may be a three-wheeled vehicle, a four-wheeled vehicle, or a snowmobile. Further, the rear arm 9 and the drive unit 24 may be separate. Further, the fuel supply device 38 may be based on fuel injection supply by a fuel injection valve.

1 is an overall side view of a vehicle. FIG. 2 is a partially enlarged detail view of FIG. 1. FIG. 2 is a partial plan view of what is shown in FIG. 1. FIG. 4 is a partially enlarged sectional view of FIG. 3. FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. FIG. 6 is a cross-sectional view taken along line 6-6 in FIG. FIG. 7 is a view on arrow 7-7 in FIG. 3. FIG. 5 is a development view of what is shown in FIG. 4.

Explanation of symbols

16 Center 17 Road surface 18 Drive device 21 Internal combustion engine 22 Belt winding device 26 Crankcase 27 Axle 28 Middle part 29 Bearing 30 Crankshaft 31 Axle 32 Cylinder 33 Cylinder hole 34 Piston 35 Connecting rod 36 Combustion chamber 37 One end 38 Others End 39 One side wall 40 Other side wall 41 Crank chamber 44 Drive pulley 51 One side space 52 Housing 59 Cover body 61 Other side space 64 Valve mechanism 65 Cam shaft 66 Chain winding means 67 Drive sprocket 68 Drive sprocket 69 Chain 72 Starter 73 Starter motor 74 Starter clutch 77 Starter gear 78 Clutch body 80 Fastener 81 Male screw 82 Nut body 85 Lubricator 86 Oil pan 87 Oil pump 88 Drive gear 89 Driven gear 97 Twist tool 98 Opening

Claims (7)

A four-cycle internal combustion engine as a drive source and a belt winding device that can transmit a driving force output from the internal combustion engine to a driven side so that the internal combustion engine can rotate around a certain axis. A crankshaft supported by a crankcase by a bearing and supporting a drive pulley of the belt winding device, and an endless transmission belt winding that is supported by the crankshaft and can transmit power to a camshaft of a valve mechanism. A drive sprocket, a starter clutch supported by the crankshaft and capable of connecting and disconnecting power transmission from the starter motor to the crankshaft, and supported by the crankshaft and capable of transmitting drive force to the lubricating oil pump In a drive device comprising a drive gear that
A driving apparatus, wherein the driving pulley and the driving sprocket are supported on one end of the crankshaft, and the starter clutch and driving gear are supported on the other end of the crankshaft.   The drive device according to claim 1, wherein the drive sprocket is positioned closer to the bearing than the drive pulley.   The starter clutch is supported on the crankshaft so as to be free to rotate about the axis of the crankshaft, and a starter gear that can input a driving force from the starter motor, and the starter clutch rotates with the crankshaft. A clutch body supported by a crankshaft and capable of only inputting a driving force from the starter gear and having a smaller outer diameter than the starter gear, and the clutch body is located on the drive gear side of the starter gear. The drive device according to claim 1, wherein the drive device is positioned at a position.   The drive device according to any one of claims 1 to 3, wherein the drive gear is positioned closer to the bearing than the starter clutch.   A housing that protrudes from the side wall of the crankcase toward the other end side in the axial direction of the crankshaft and accommodates the other end portion of the crankshaft is fitted into the housing and is detachably fixed to the housing. A cover body is provided, a space defined by the cover body is formed, and the starter clutch and the drive gear are accommodated in the space so that they can be lubricated. The drive device as described in any one of them.   The starter clutch is supported on the other end of the crankshaft by a fastener that is screwed to the crankshaft by twisting around the axis of the crankshaft, and the housing corresponds to the radially outward direction of the fastener The drive device according to claim 5, wherein an opening that allows insertion and removal of the tool for twisting the fastener is formed only in a part of the circumferential direction of the fastener, and the opening is closed so as to be openable and closable.   A straddle-type vehicle equipped with the drive device according to any one of claims 1 to 6 as a drive source for traveling.

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