JPH11123941A - Power transmission for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely transmit power by a centrifugal cluch by keeping a constant space between a centrifugal weight shoe and a cluch housing, and to facilitate replacement for the centrifugal weight shoe to enhance ability for maintenance and repair. SOLUTION: The first bearing 209 located in both sides of a centrifugal weight shoe 245 and journaling a crank shaft 207 to a crank case 201, and the second bearing 241 journaling one end of the crank shaft 207 to a cluch housing 243 or a primary shaft 251 are provided, a cluch chamber 232 storing a centrifugal cluch A and a transmission chamber 233 storing the driving side 250 of a V-belt continuously variable transmission B are partitioned, a partitioning wall 231 penetrated with the cluch housing 243 or the primary shaft 251 is provided, the third bearing 242 journaling the cluch housing 243 to the partitioning wall 231 is provided, and the fourth bearing 252 journaling the other end of the primary shaft 251 to a transmission cover 230 for covering the V-belt continuously variable transmission B is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission device for an engine provided in a four-wheeled vehicle such as a buggy running on uneven terrain.

[0002]

2. Description of the Related Art For example, a four-wheeled vehicle such as a buggy vehicle traveling on uneven terrain is provided with a power transmission device having a centrifugal clutch and a V-belt continuously variable transmission, and travels by transmitting engine power to a drive unit. There is something to do. This power transmission device includes a crankshaft housed in a split crankcase,
A centrifugal clutch is interposed between a primary shaft on the drive side of the V-belt continuously variable transmission that extends coaxially with the crankshaft, and one end of the crankshaft and one end of the primary shaft. There is a centrifugal weight shoe carried at one end and a clutch housing that is covered by the centrifugal weight shoe and rotates integrally with the primary shaft.

[0003]

As described above, in the case where the drive side of the V-belt continuously variable transmission and the centrifugal clutch are arranged on the shaft of the crankshaft, stress from the piston is applied to one end of the crankshaft. The stress from the V-belt is applied to the clutch housing of the centrifugal clutch via the primary shaft of the V-belt continuously variable transmission. For this reason, the distance between the centrifugal weight shoe and the clutch housing changes, and power transmission by the centrifugal clutch may not be performed reliably.

A drive side of a V-belt continuously variable transmission and a centrifugal clutch are assembled to a crankshaft and a primary shaft extending coaxially with the crankshaft. Although it is necessary, the centrifugal clutch is supported by the crankcase,
It is necessary to replace one of the left and right split crankcases and replace the centrifugal weight shoe, which is inferior in maintainability. The present invention has been made in view of the above-mentioned problem, and has been developed in consideration of the above problem. It is an object of the present invention to provide an engine power transmission device in which power can be reliably transmitted by a centrifugal clutch while maintaining a constant interval, and a centrifugal weight shoe can be easily replaced to improve maintainability.

[0005]

Means for Solving the Problems In order to solve the above problems and achieve the object, the present invention has the following constitution.

The invention according to claim 1 is characterized in that the crankshaft includes a crankshaft housed in a crankcase and a drive-side primary shaft of a V-belt continuously variable transmission that extends coaxially with the crankshaft. A centrifugal clutch is interposed between one end of the shaft and one end of the primary shaft, the centrifugal clutch is a centrifugal weight shoe carried on one end of the crankshaft, and the centrifugal weight shoe is covered by the centrifugal weight shoe. In a power transmission device for an engine having a clutch housing that rotates integrally with a primary shaft, a first bearing that is located on both sides of the centrifugal weight shoe and supports the crankshaft on the crankcase, and one end of the crankshaft. And a second bearing that supports the clutch housing or the primary shaft, and a clutch chamber that houses the centrifugal clutch. A third bearing for partitioning a transmission chamber accommodating the drive side of the V-belt continuously variable transmission and for providing a partition wall through which the clutch housing or the primary shaft passes, and supporting the clutch housing to the partition wall. And a fourth bearing for pivotally supporting the other end of the primary shaft to a transmission cover covering the V-belt continuously variable transmission. ].

According to the first aspect of the present invention, the first bearing is located on both sides of the centrifugal weight shoe and supports the crankshaft on the crankcase, and the first bearing supports one end of the crankshaft on the clutch housing. While the second bearing is provided, the third bearing that supports the clutch housing to the partition wall and the fourth bearing that supports the other end of the primary shaft to the transmission cover are provided. Even if stress is applied or stress from the V-belt continuously variable transmission is applied to the clutch housing via the primary shaft,
Power can be reliably transmitted by the centrifugal clutch while keeping the distance between the centrifugal weight shoe and the clutch housing constant. Further, a clutch chamber accommodating the centrifugal clutch and a transmission chamber accommodating the V-belt continuously variable transmission are separated, and a partition wall through which the clutch housing or the primary shaft passes is detachably attached to the crankcase. In addition, since the clutch housing is pivotally supported via the third bearing, the centrifugal weight shoe can be easily replaced simply by removing the partition wall from the crankcase without separating the left and right crankcases, thereby improving maintainability.

[0008] One end of the crankshaft may be directly supported on the clutch housing, or one end of the crankshaft may be indirectly supported on the clutch housing via a boss member or the like externally fitted to the crankshaft. Is also good. In addition to the case where the clutch housing is directly supported on the partition wall, the clutch housing may be supported on the partition wall indirectly via a clutch input shaft or a primary shaft to which the clutch housing is fixed.

According to a second aspect of the present invention, there is provided a method of manufacturing a vehicle comprising the steps of: "while the partition wall covers an opening formed in the crankcase and is removably attached to the crankcase, the clutch housing passes through the opening. The power transmission device for an engine according to claim 1, wherein the power transmission device has a size as large as possible. ].

According to the second aspect of the present invention, the partition wall covers the opening formed in the crankcase and is removably attached to the crankcase while the clutch housing can pass through the opening. Because of the size, replacement of the centrifugal weight shoe may be performed by removing the partition wall from the crankcase and removing the clutch housing through the opening. Therefore, the centrifugal weight shoe can be easily replaced simply by removing the partition wall from the crankcase without disassembling the crankcase, thereby improving maintainability.

According to a third aspect of the present invention, a power generator and a recoil starter are provided on a crankshaft end opposite to the centrifugal clutch with respect to the engine cylinder. A power transmission device for the engine according to the above. ].

According to the third aspect of the present invention, since the generator and the recoil starter are provided on the end of the crankshaft opposite to the centrifugal clutch with the cylinder interposed therebetween, the heavy V belt is continuously variable. Since the drive side and the centrifugal clutch of the transmission and the generator and the recoil starter are arranged separately on the left and right sides of the cylinder, the right and left weight balance of the engine is improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a power transmission device for an engine according to the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a side view of a four-wheel drive four-wheel vehicle equipped with an engine power transmission device, FIG. 2 is a plan view showing the configuration of a drive system of the four-wheel drive four-wheel vehicle, and FIG. FIG. 4 is a sectional view taken along line IV-IV in FIG. 3, FIG. 5 is a vertical sectional view on the drive side of a centrifugal clutch and a V-belt continuously variable transmission, and FIG. It is sectional drawing which follows the VI-VI line of No. 5.

The four-wheeled vehicle 1 of this embodiment is a buggy vehicle that travels on rough terrain, and the vehicle body can run freely by a pair of left and right front wheels 2 at the front and by a pair of left and right rear wheels 3 at the rear. It is supported by. The body frame 4 of the four-wheeled vehicle 1 has a pipe frame structure, which has a pair of left and right upper tubes 4a and a down tube 4b that are substantially rectangular in a side view, and a reinforcing frame 4c is provided between the tubes 4a and 4b. , 4d are installed.

The vehicle body frame 4 at the front of the vehicle body
A steering pipe 5 is erected diagonally upward toward the rear on the vehicle body center line L1, and a steering shaft 100 is rotatably inserted into the steering pipe 5. A bar handle 6 is provided at an upper end of the steering shaft 100.

A pair of left and right front wheels 2 are steered by a steering operation of a bar handle 6. The front wheels 2 are rotatably supported by a front wheel shaft 7, and are vertically moved by a front cushion 8 on the body frame 4. It is movably suspended. The front wheel 2 is covered by a front fender 9 integrally formed of resin.

On the other hand, a fuel tank 10 is disposed at the upper center of the vehicle body and behind the steering pipe 5, and a seat 11 is disposed behind the fuel tank 10. The seat 11 is supported by a seat rail frame 4e extending rearward from the upper tube 4a. Further, a four-cycle single-cylinder engine 12 is provided in the center of the vehicle body and below the fuel tank 10. The engine 12 is mounted on the vehicle body frame 4 so that the crankshaft 207 extends in the vehicle width direction. The engine 12 includes a pair of left and right brackets 13 fixed to a reinforcing frame 4c, and an upper tube 4a.
4 via a pair of left and right brackets 14 fixed to the
The points are mounted and supported on the body frame 4. The center of the engine 12, that is, the center L2 of the cylinder is
1 is offset to the left by a.

An air cleaner 15 constituting an intake system of the engine 12 is provided below the seat 11, and an intake duct 16 connected to the air cleaner 15 is
The lower part is open behind the fuel tank 10. The air cleaner 15 is connected to the engine 12 via the carburetor 17.
Is connected to the intake side.

The exhaust pipe 18 extending forward from the exhaust side of the engine 12 is turned toward the right side of the vehicle body, that is, on the side opposite to the side where the engine 12 is offset, and then turned to the side of the engine 12. And extends to the rear of the vehicle body, and is connected to the muffler 19 through the inside of one (right) down tube 4b.

On the other hand, behind the engine 12, the upper tube 4 a and the down tube 4
A front end of a rear arm 21 is attached to a pair of left and right rear arm brackets 20 fixed to a connection portion with the pivot shaft 22.
It is pivotally mounted by a vertical swing. Rear arm 2
A pair of right and left rear wheels 3 are provided at the rear end of the rear wheel shaft 2.
3 rotatably supported. Rear arm 21
Is suspended from the body frame 4 by a rear cushion 24.

The rear arm 21 is connected to a gear box 25, and the four-wheel vehicle 1 employs a so-called shaft drive system as a drive system. The drive shaft 26 extends from the rear of the engine 12 toward the rear of the vehicle body. Is connected via a universal joint 102 to one end of a drive shaft 101 inserted into the rear arm 21. The other end of the drive shaft 101 is a gear box 25
It is connected to a not-shown bevel gear mechanism housed inside.

When the engine 12 is driven, the rotation of the drive shaft 26 causes the drive shaft 10 in the rear arm 21 to rotate.
The direction of the rotation of the drive shaft 101 is changed by 90 ° by a bevel gear mechanism in the gear box 25 and transmitted to the rear wheel shaft 23, and the rotation of the rear wheel shaft 23 drives the rear wheel 3 to rotate. As a result, the four-wheeled vehicle 1 is driven.

On the other hand, an upper end of the rear cushion 24 is supported by a pair of brackets 27 fixed to the cross pipe 4f of the body frame 4 by a shaft 28, and a lower end thereof is fixed to a gear box 25 of the rear arm 21. The bracket 29 is supported by a shaft 30. The rear wheel 3 is covered by a rear fender 900 integrally formed of resin.

The rear cushion 24 is offset by b to the left with respect to the vehicle center line L1. By offsetting the rear cushion 24 by b with respect to the vehicle body center line L1, the rear cushion 2 is offset from the vehicle body center line L1.
The engine 12 and the rear cushion 24, which are offset by a on the same side as the engine 4, are arranged on the same side, so that the width of the rear arm 21 and the body frame 4 can be reduced, and the width of the engine 12 can be reduced. Can be.

A front differential (front differential) 32 is disposed on the vehicle center line L 1 in front of the engine 12, and an input shaft 31 extends from the front differential 32 to the vehicle center line L 1.
1 extends rearward. This input shaft 31
The front end of a drive shaft 33 extending from the front of the engine 12 toward the front of the vehicle body is connected by a universal joint 103. Drive shaft 33
Is further connected to a drive shaft 293 via a universal joint 34. A pair of drive shafts 36 for transmitting a driving force to the front wheels 2 extend outward from the left and right sides of the front differential 32, and each front wheel 2 has an upper arm disposed above and below the drive shaft 36. It is suspended on the vehicle body side by a lower arm 37 and a front cushion 8 so as to be vertically movable.

When the engine 12 is driven, its rotation is transmitted to the rear wheels 3 and simultaneously transmitted to the front wheels 2 via the drive shaft 33, the front differential 32 and the drive shaft 36, so that the front wheels 2 and the rear wheels 3 are simultaneously driven. Driven. in this way,
By transmitting the power of the engine 12 to the front wheels 2 and the rear wheels 3, which are drive units, the four-wheeled vehicle 1 is driven.

Next, a power transmission device of the engine 12 mounted on the four-wheel drive four-wheel vehicle 1 will be described. FIG.
Are the drive side 250 and the driven side 270 of the V-belt continuously variable transmission.
The cross section showing the driving side 250 shows the high speed state, the cross section showing the driven side 270 shows the lower half cross section showing the high speed state,
The upper half section shows a low speed state. The cross section showing the drive side 250 of the V-belt continuously variable transmission in FIG. 5 shows a low-speed state.

Left and right split crankcase 2 of engine 12
On the cylinder block 202, a cylinder head 202 is mounted.
Are mounted, and a head cover 200 is further provided. The split surface of the left and right split crankcase 201 is located on the cylinder center L2 as shown in FIG.

A combustion chamber 205 is formed between a cylinder 204 and a piston 204 reciprocally provided in the cylinder block 202. The piston 204 is connected to a crankshaft 207 by a connecting rod 206. The crankshaft 207 is mounted on the left and right crankcases 201 by a bearing 208 on the cam chamber side and a first bearing 20 on the clutch chamber side.
9 so as to be rotatable.

At one end of the crankshaft 207, a camshaft driving gear 210, a generator 211 and a recoil starter 99 are mounted.
0 is provided. A cam chain 214 is wound around the camshaft drive gear 210 and the sprockets 213 of the intake and exhaust camshafts 212, and the camshaft 212 rotates in conjunction with the camshaft drive gear 210. The camshaft 212 is provided between the cylinder head 203 and the head cover 200.
The intake and exhaust valves (not shown) are opened and closed at a predetermined timing by the rotation of the cam shaft 212 to open and close the combustion chamber 205.
The mixture is supplied from the carburetor 17, and the mixture is burned and discharged to the exhaust pipe 18.

At the other end of the crankshaft 207, a balancer drive gear 215, a centrifugal clutch A and a drive side 250 of a V-belt continuously variable transmission B are arranged. Reference numeral 220 denotes a balancer shaft supported by the crankcase 201. The balancer drive gear 215 is connected to the balancer gear 2 of the balancer shaft 220.
21 mesh with each other, and the balancer shaft 220 rotates in conjunction with the balancer drive gear 215.

A transmission cover 230 is detachably provided on one of the left and right split crankcases 201. A clutch wall 232 and a transmission chamber 233 are defined inside the transmission cover 230 by a partition wall 231. 231
Is removably fastened and fixed to one of the left and right split crankcases 201 by a fastening bolt 234. The crankcase 201 includes a clutch chamber 232 and a crank chamber 99.
8 is formed, and oil flows from the clutch chamber 232 to the crank chamber 998.

The transmission cover 230 includes a sound insulation cover 96.
0 is detachably fastened and fixed by a screw 961.
A centrifugal clutch A is disposed in the clutch chamber 232, and a transmission side 25 of the V-belt continuously variable transmission B is disposed in the transmission chamber 233.
0 is arranged.

In this embodiment, the generator 2 is mounted on the end of the crankshaft opposite to the centrifugal clutch A with respect to the cylinder.
11 and the recoil starter 990, the drive side of the V-belt continuously variable transmission B and the centrifugal clutch A, which are heavy objects, and the generator 211 and the recoil starter 990 are arranged separately on the left and right sides of the cylinder. Thus, the right and left weight balance of the engine is improved.

The centrifugal clutch A has a clutch output shaft 240
Of the clutch output shaft 240 is supported by the crankshaft 207 via the second bearing 241, and the third bearing 2 is supported by the outside of the clutch output shaft 240.
It is pivotally supported by the partition wall 231 via 42. The second bearing 241 is connected to the clutch output shaft 2 by the circlip 970.
It is supported by 40. Further, the third bearing 242 is supported by the clutch output shaft 240 by the circlip 971 and is supported by the partition wall 231 by the pressing plate 972.

A clutch housing 243 is fixed to the clutch output shaft 240 by rivets 244, and a centrifugal weight shoe 245 is arranged inside the clutch housing 243. One end 24 of the centrifugal weight shoe 245
5a is rotatably supported on the support pin 246 as a fulcrum,
The support pins 246 are provided on an inner plate 247, and the inner plate 247 is fixed to a clutch input shaft 248, and the clutch input shaft 248 is
7 so as to be integrally rotatable.

The centrifugal weight shoe 245 includes a crankshaft 207, a clutch input shaft 248, and the inner plate 24.
7, the one end 245a pivots outward with the support pin 246 as a fulcrum, and the other end 245b opens outward due to centrifugal force and slides into the clutch housing 243 to engage the clutch. The torque is transmitted to the housing 243 so that the clutch output shaft 240
7 and rotate together. A one-way clutch 249 for engine braking is disposed between the clutch input shaft 248 and the clutch output shaft 240.

As shown in FIG. 6, the one-way clutch 249 includes an inner case 249a and an outer case 249.
b, the inner case 249a and the outer case 249.
b) and a clutch piece 249c disposed between the two. The inner case 249a is a clutch input shaft 2
48, and is detachably fitted to the crankshaft 207. The outer case 249b is fixed to the clutch output shaft 240, and is detachably fitted to the clutch input shaft 248. The normal rotation direction of the clutch output shaft 240 is the a direction, and the clutch output shaft 240 is free during normal traveling in which the crankshaft 207 rotates in the c direction. The rotation direction during engine braking is locked in the Take it.

The clutch output shaft 240 is integrally rotatably connected to the primary shaft 251 on the drive side 250 of the V-belt continuously variable transmission B. Tip 2 of primary shaft 251
51a is a transmission cover 230 via a fourth bearing 252.
Are supported by a support portion 230e provided at the bottom. Support part 23
At 0e, a seal 253 and a retaining plate 254 are provided to seal the fourth bearing 252.

The spline portion 251 of the primary shaft 251
b, a fixed sheave 255 is spline-engaged. Further, a collar 256 and a cam plate 257 are mounted, and these are tightened and fixed to the primary shaft 251 by a nut 258. The fixed sheave 255 is integrated with the primary shaft 251. It is rotatable. The fixed sheave 255 has a disk shape, and a plurality of cooling air introducing fins 255b are integrally formed on the side opposite to the conical surface 255a, and external air is sucked into the transmission chamber 233 by rotation.

A movable sheave 259 is engaged with the collar 256 via a bush 260 so as to be slidable in the axial direction of the primary shaft 251. The conical surface 259 a of the movable sheave 259 faces the conical surface 255 a of the fixed sheave 255. The V-belt 261 is pinched during this time. A guide portion 259 b protruding inward is formed integrally with an opening of the movable sheave 259 opposite to the conical surface 259 a, and the outer periphery of the cam plate 257 is engaged via a slider 262.

The movable sheave 259 is formed with a cam portion 259c, and the cam plate 257 is formed with an inclined portion 257a facing the cam portion 259c.
A centrifugal weight 263 is provided between 7a. The centrifugal weight 263 is connected to the cam portion 259c of the movable sheave 259 according to the centrifugal force generated by the rotation of the primary shaft 251.
Guided by the inclined portion 257a of the cam plate 257,
The movable sheave 259 is moved in the radial direction to move the movable sheave 259 in the axial direction, and the conical surface 25 of the movable sheave 259 and the fixed sheave 255 is moved.
The speed is changed by changing the interval between 9a and 255a.

As described above, the left and right split crankcase 20
1, a primary shaft 251 on the drive side 250 of the V-belt continuously variable transmission B extending coaxially with the crankshaft 207, and one end of the crankshaft 207 and one end of the primary shaft 251. Centrifugal clutch A between
The centrifugal clutch A is provided with a centrifugal weight shoe 245 carried on one end of a crankshaft 207, and a clutch housing 243 which is covered by the centrifugal weight shoe 245 and rotates integrally with the primary shaft 251.
have.

A first bearing 209 that supports the crankshaft 207 on the crankcase 201 and a second bearing 241 that supports one end of the crankshaft 207 on the clutch housing 243 are positioned on both sides of the centrifugal weight shoe 245. Although one end of the crankshaft 207 may be directly supported on the clutch housing 243,
One end of 7 may be indirectly supported on the clutch housing 243 via a boss member or the like fitted to the outside of the crankshaft 207.

A hollow portion is formed at the center of the primary shaft 251, while one end of the crankshaft 207 is inserted into the hollow portion, and the outer peripheral surface of the crankshaft 207 is
The second bearing 241 may be arranged between the inner bearing 51 and the inner peripheral surface.

Further, a clutch chamber 232 accommodating the centrifugal clutch A and a transmission chamber 233 accommodating the drive side of the V-belt continuously variable transmission B are separated from each other.
Although the partition wall 231 through which the first member 1 penetrates is detachably attached to the crankcase 201, the clutch input shaft 240 may be fixed to the clutch housing 243 or the clutch housing 243 so as to penetrate the partition wall 231. Partition wall 2 of clutch housing 243
Although the third bearing 242 is provided to support the clutch 31, the clutch housing 243 may be directly supported to the partition wall 231, or may be indirectly connected to the clutch input shaft 240 or the primary shaft 251 to which the clutch housing 243 is fixed. Alternatively, the partition wall 231 may be pivotally supported. further,
A fourth bearing 252 that supports the other end of the primary shaft 251 on a transmission cover 230 that covers the V-belt continuously variable transmission B is provided.

The centrifugal weight shoe 24 of the centrifugal clutch A
5 is replaced by removing the transmission cover 230, the V-belt 261 of the V-belt continuously variable transmission B, the movable sheave 259, and the fixed sheave 255, and then removing the fastening bolts 234 to separate the partition wall 231, the primary shaft 251, and the like. Second bearing 2
41, the third bearing 242, the clutch input shaft 240, and the clutch housing 243 are detached with an assembly, and then the centrifugal weight shoe 245 is detached.

As described above, in this embodiment, the crankshaft 20 is positioned on both sides of the centrifugal weight shoe 245.
Bearing 209 that supports the first bearing 7 on the crankcase 201
And one end of the crankshaft 207 to the clutch housing 24.
3 and a third bearing 242 for supporting the clutch housing 243 on the partition wall 231 and the other end of the primary shaft 251 for the transmission cover 2.
30 is provided with a fourth bearing 252 that is pivotally supported, the one end of the crankshaft 207 is subjected to stress from the piston 204, or the clutch housing 2 is connected via the primary shaft 251.
Even if stress from the V-belt continuously variable transmission B is applied to 43, the power transmission by the centrifugal clutch A can be reliably performed by keeping the distance between the centrifugal weight shoe 245 and the clutch housing 243 constant. it can. Further, the clutch chamber 232 accommodating the centrifugal clutch A and the transmission chamber 233 accommodating the V-belt continuously variable transmission B are separated, and a partition wall 231 through which the clutch housing or the primary shaft 251 penetrates is attached to and detached from the crankcase 201. The third bearing 242 is attached to the partition wall 231 freely.
, The clutch housing 243 is pivotally supported, so that the centrifugal weight shoe 245 can be easily replaced simply by removing the partition wall 231 from the crankcase 201 without separating the right and left crankcases 201, thereby improving maintainability.

The partition wall 231 covers the opening 999 formed in the crankcase 201 and is removably attached to the crankcase 201, while the opening 999 is sized to allow the clutch housing 243 to pass therethrough. Therefore, the replacement of the centrifugal weight shoe 245 may be performed by removing the partition wall 231 from the crankcase 201 and removing the clutch housing 243 through the opening 999. Therefore, the centrifugal weight shoe 245 can be easily replaced simply by removing the partition wall 231 from the crankcase 201 without disassembling the crankcase 201, thereby improving maintainability.

A support cylinder 272 and a fixing plate 273 are fixed to the main shaft 271 by a fastening nut 274, and are rotatable integrally with the main shaft 271. A fixed sheave 275 is fixed to the fixed plate 273 by a rivet 276. The support cylinder 272 has a slide cylinder 277
Is provided so as to be movable in the axial direction.
The movable sheave 278 is fixed to. Slide tube 2
77 and a spring receiving member 279 fixed to the main shaft 271.
Is provided, and the movable sheave 2 is
78 is constantly biased toward the fixed sheave 275 side.

In the power transmission device of the engine 12, as shown in FIG. 3, the main shaft 271 is disposed above the horizontal plane L3 passing through the axis O1 of the crankshaft 207 of the engine 12, and the drive shaft is disposed below the horizontal plane L3. Shaft 281 and output shaft 28
2 are arranged vertically, and the crankshaft 207 and the main shaft 27
1, the drive shaft 281 and the output shaft 282 are all supported by the left and right split crankcase 201.

The main shaft 271 is rotatably supported by the split crankcase 201 via bearings 300 and 301, and the gears 271 a and 271 b of the main shaft 271 are connected to the drive shaft 28.
1 meshes with gears 283 and 284 rotatably provided. A dog clutch 285 is provided between the gear 283 and the gear 284 so as to be movable in the axial direction. When the dog clutch 285 is not engaged with any of the gear 283 and the gear 284, the neutral position is established. When the gear is engaged with the gear 284, the reduction ratio becomes small (the degree of reduction becomes small), and when the gear 284 is engaged, the reduction ratio becomes large (the degree of reduction becomes large). The gear 281 a fixed to the drive shaft 281 meshes with the gear 286 of the output shaft 282, and the torque of the drive shaft 281 is transmitted to the output shaft 282.

The drive shaft 281 includes bearings 302 and 303
Through the main shaft 2
The gear 271c of the 71 is a gear 288 of the counter shaft 287.
a, and the gear 288b meshes with a gear 289 that idles on the drive shaft 281. Gear 288a,
288 b idles integrally on the counter shaft 287, and the dog clutch 290 that rotates integrally with the drive shaft 281 can be engaged with the gear 289. Therefore, when the vehicle is moving in reverse, the dog clutch 285 is in the neutral position, the dog clutch 290 is engaged with the gear 289, and the main shaft 27
1 rotates from the gear 271c to the gear 2 of the counter shaft 287.
The gear 28 of the drive shaft 281 through the gears 88a and 288b
9 and the drive shaft 281 rotates in the reverse direction.

The output shaft 282 is supported by left and right crankcases 201 via bearings 304 and 305, and a bevel gear 291 fixed to the output shaft 282 is a bevel gear of the drive shaft 26 supported by the crankcase 201. 294
And the bevel gear 292 of the drive shaft 293. As a result, the rotational force of the output shaft 282 is
The power is transmitted to the bevel gear 294 and the drive shaft 293 from the bevel gear 294 and the drive shaft 293.

As described above, the axis O1 of the crankshaft 207 is
The main shaft 271 is disposed above a horizontal plane L3 passing through the vehicle, and the drive shaft 281 and the output shaft 282 are disposed vertically below, so that the engine 12 is compact in the vertical direction and the front-rear direction (vehicle front-rear direction) of the engine 12. Can be The vertical plane L4 passing through the axis O2 of the main shaft 271 is connected to the gears 283, 284, 2 of the drive shaft 281.
81a and 289 intersect with the gear 286 on the output shaft 282, so that the engine 12 can be made compact in the front-rear direction of the engine 12 (vehicle front-rear direction).

The crankshaft 207 and the main shaft 271
And the crankshaft 2 when viewed in the crankshaft direction.
07 and the main shaft 271, the balancer shaft 220 is provided inside the V-belt 261 of the V-belt continuously variable transmission B.
Has been arranged. Since the V-belt 261 is wound around the crankshaft 207 and the main shaft 271, the two shafts are separated from each other. However, since the balancer shaft 220 is disposed using the space, the front-rear direction of the engine 12 ( The engine 12 can be made compact in the vehicle front-rear direction).

The counter shaft 2 having gears 288a and 288b that mesh with the gear 271c on the main shaft 271 and selectively mesh with the gear 289 on the drive shaft 281.
87, and the axis O3 of the counter shaft 287 is referred to as the axis O1 of the crankshaft 207 when viewed in the crankshaft direction.
And the axis O2 of the main shaft 271 and the axis O4 of the drive shaft 281 are arranged inside a triangle K formed by connecting them. As described above, since the counter shaft 287 is disposed by utilizing the space inside the triangle K formed by the crankshaft 207, the main shaft 271 and the drive shaft 281, the engine 12 can be made more compact.

Further, the axis O3 of the counter shaft 287 is defined by the crankshaft 207 and the main shaft 2 when viewed in the crankshaft direction.
71 is disposed inside the V-belt 261 of the V-belt continuously variable transmission B wound around 71. Since the V-belt 261 is wound around the crankshaft 207 and the main shaft 271, both shafts are separated from each other. However, the space for the counter shaft 287 is used to reduce the size of the engine 12. It can be achieved even more.

The air duct 40 communicates with the transmission room 233.
0, and exhaust ducts 401 and 402 are provided. The outside air is introduced from the air duct 400 to the transmission room 233 to cool the V-belt continuously variable transmission B, and the exhaust is exhausted from the exhaust ducts 401 and 402 to improve the cooling performance. Can be. Also, the exhaust ducts 401 and 402 are assembled on the way, and
03 makes it easy to manage the exhaust duct,
In addition, the cooling performance of the cylinder 430 can be improved.

[0060]

As is apparent from the above description, according to the first aspect of the present invention, the centrifugal weight shoe is located on both sides,
A first bearing that supports the crankshaft to the crankcase; a second bearing that supports one end of the crankshaft to the clutch housing; a third bearing that supports the clutch housing to the partition wall; Since the fourth bearing having the other end pivotally supported by the transmission cover is provided, stress from the piston is applied to one end of the crankshaft or stress from the V-belt continuously variable transmission is applied to the clutch housing via the primary shaft. In this case, the distance between the centrifugal weight shoe and the clutch housing can be kept constant, and the power can be reliably transmitted by the centrifugal clutch.

Further, a clutch chamber accommodating the centrifugal clutch and a transmission chamber accommodating the V-belt continuously variable transmission are separated, and a partition wall through which the clutch housing or the primary shaft passes is detachably attached to the crankcase. Since the clutch housing is pivotally supported on the partition wall via the third bearing, the centrifugal weight shoe can be easily replaced simply by removing the partition wall from the crankcase without separating the left and right crankcases, improving serviceability. I do.

According to the second aspect of the present invention, the partition wall covers the opening formed in the crankcase and is removably attached to the crankcase, while the opening has a size that allows the clutch housing to pass through. Therefore, replacement of the centrifugal weight shoe may be performed by removing the partition wall from the crankcase and removing the clutch housing through the opening. Therefore, the centrifugal weight shoe can be easily replaced simply by removing the partition wall from the crankcase without disassembling the crankcase, thereby improving maintainability.

According to the third aspect of the present invention, the generator and the recoil starter are provided on the end of the crankshaft opposite to the centrifugal clutch with the cylinder interposed therebetween. Since the drive side and the centrifugal clutch, and the generator and the recoil starter are disposed separately on the left and right sides of the cylinder, the right and left weight balance of the engine is improved.

[Brief description of the drawings]

FIG. 1 is a side view of a four-wheel drive four-wheel vehicle equipped with an engine power transmission device.

FIG. 2 is a plan view showing a configuration of a drive system of a four-wheel drive four-wheel vehicle.

FIG. 3 is a diagram showing an arrangement of each shaft of a power transmission device of an engine.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3;

FIG. 5 is a longitudinal sectional view of a drive side of a centrifugal clutch and a V-belt continuously variable transmission.

6 is a sectional view taken along the line VI-VI in FIG.

[Explanation of symbols]

 12 Engine 201 Crankcase 207 Crankshaft 209 First bearing 230 Transmission cover 231 Partition wall 232 Clutch chamber 233 Transmission chamber 241 Second bearing 242 Third bearing 243 Clutch housing 245 Centrifugal weight shoe 250 V-belt continuously variable transmission B Drive side 251 Primary shaft 252 Fourth bearing A Centrifugal clutch BV belt continuously variable transmission

Claims (3)

[Claims] 1. A crankshaft housed in a crankcase and a primary shaft on the drive side of a V-belt continuously variable transmission that extends coaxially with the crankshaft, and includes one end of the crankshaft and the primary shaft. A centrifugal clutch is interposed between the centrifugal clutch and one end of the crankshaft. The centrifugal clutch is mounted on one end of the crankshaft, and is covered with the centrifugal weight shoe and rotates integrally with the primary shaft. In a power transmission device for an engine having a clutch housing, a first bearing is provided on both sides of the centrifugal weight shoe to support the crankshaft on the crankcase, and one end of the crankshaft is connected to the clutch housing or the primary. A second bearing for supporting the shaft, a clutch chamber accommodating the centrifugal clutch and a V-belt continuously variable transmission; A clutch housing or a partition wall through which the primary shaft penetrates, a third bearing that pivotally supports the clutch housing with the partition wall, and a third bearing other than the primary shaft. A power transmission device for an engine, comprising a fourth bearing whose end is pivotally supported on a transmission cover that covers the V-belt continuously variable transmission. 2. The method according to claim 2, wherein the partition wall covers an opening formed in the crankcase and is removably attached to the crankcase, while the opening is sized to allow the clutch housing to pass therethrough. The power transmission device for an engine according to claim 1, wherein: 3. The engine power transmission device according to claim 1, wherein a generator and a recoil starter are provided on an end of the crankshaft opposite to the centrifugal clutch with respect to the cylinder of the engine. .