JPH0790701B2 - Power transmission device for straddle-type four-wheel drive vehicle - Google Patents

Description

TECHNICAL FIELD The present invention relates to a power transmission device for a straddle-type four-wheel drive vehicle.

(Prior Art) Some four-wheel drive vehicles are conventionally configured as follows.

That is, a pair of left and right front wheels are supported by the front part of the body frame, and a pair of left and right rear wheels are supported by the rear part of the same body frame. The left and right front wheels are connected to each other by a front wheel differential device disposed between the front wheels, and the front wheel differential device is provided above the front portion of the vehicle body frame.
An engine is supported midway in the front-rear direction of the vehicle body frame, and the front wheel differential device is interlockingly connected to the crankshaft of the engine through an input shaft, a front wheel output shaft, and a universal joint shaft. The respective rear wheels are interlockingly connected to the shaft through an input shaft, an intermediate shaft, a rear wheel output shaft, and a universal joint shaft. Further, the front wheel output shaft and the rear wheel output shaft are arranged between the front and rear wheels in the front-rear direction and on the front side of the center thereof.

Then, the driving force of the engine is the crankshaft, the input shaft,
While the front wheel output shaft, the front wheel propulsion shaft, and the front wheel differential device are sequentially transmitted to each front wheel, the same driving force is applied to the crank shaft, the input shaft, the intermediate shaft, the rear wheel output shaft, and the rear wheel. It is transmitted to each rear wheel through the vehicle propulsion shaft, whereby the four-wheel drive vehicle can run on the road surface by the four-wheel drive of the front and rear wheels.

(Problems to be Solved by the Invention) By the way, since the straddle-type four-wheel drive vehicle is scheduled to run on a rough road and is different from an ordinary vehicle, the following points are further improved. Is required.

First, when a four-wheel drive vehicle travels on a rough road,
The purpose of this is to prevent the front wheel differential from being adversely affected by the shock received by the front portion of the vehicle body frame against the road surface.

Secondly, a four-wheel drive vehicle is equipped with many components such as an engine, but in this case, in order to stabilize traveling, the weight balance is made uniform especially in the vehicle width direction, and the center of gravity is lowered. Is to achieve.

Thirdly, in the straddle-type four-wheel drive vehicle, in particular, in order to make it easier for the rider to straddle the vehicle body, the vehicle body is made small in the vehicle width direction.

Fourth, in the case where the axis of the front wheel output shaft extends in the front-rear direction, as in the conventional configuration, the front wheel output shaft is located between the front and rear wheels in the front-rear direction from the center thereof. When the front wheel output shaft is also disposed on the front side, the front wheel output shaft approaches the front wheel differential device, and the universal joint shaft connecting them is shortened accordingly.

In this case, if the front wheel output shaft is largely separated in the vehicle width direction from the front wheel differential device for the purpose of avoiding interference with the rear wheel output shaft, the universal joint for the axis of the front wheel output shaft is assumed. The angle formed by the shafts (hereinafter, simply referred to as the "angle" of the universal joint shaft) increases, and the power transmission efficiency between the front wheel output shaft and the universal joint shaft decreases.

Therefore, it is desired to improve the power transmission efficiency by making the front wheel differential device and the front wheel output shaft close to each other in the vehicle width direction and minimizing the "angle" of the universal joint shaft.

(Purpose of the Invention) The present invention has been made in view of the above circumstances, and an object thereof is to satisfy and meet the above-mentioned requirements.

(Structure of the Invention) A feature of the present invention for achieving the above-mentioned object is that the lower surface position of the front portion of the vehicle body frame corresponding to the position where the front wheel differential device is provided has the same structure as the vehicle body supporting the engine. It is positioned above the lower surface position of the middle part of the frame in the front-rear direction, and the differential for front wheels and engine are arranged on the upper side of the vehicle body frame.
The input shaft, the output shaft for the front wheels, the intermediate shaft, and the output shaft for the rear wheels are arranged so that their respective axial centers extend in the front-rear direction, and the crank shaft is arranged on one side portion of the vehicle body frame in the vehicle width direction. On the other hand, the front wheel output shaft and the rear wheel output shaft are disposed on the other side of the vehicle body frame, and the input shaft and the front wheel output shaft are disposed on the same axis, and The rear wheel output shaft is arranged in parallel with the input shaft and the front wheel output shaft in the width direction, and the intermediate shaft is arranged above the input shaft and the front wheel output shaft and the rear wheel output shaft. Then, the front wheel output shaft is arranged closer to the center side of the vehicle body frame in the vehicle width direction than the rear wheel output shaft, and the front wheel differential device is provided on the front end side of the front wheel output shaft via the universal joint shaft. The point is that they are linked together.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

In the drawings, reference numeral 1 is a saddle-ride type four-wheel drive vehicle, in which an engine 3 is supported by a vehicle body frame 2, and front and rear wheels 4 and rear wheels which are driven by the engine 3 are provided in front of and behind the vehicle body frame 2. A device 5 is supported. A bar handle 7 and a fuel tank 8 are provided on the front upper portion of the vehicle body frame 2, and a seat 9 is provided on the rear side of the vehicle body frame 2 behind the fuel tank 8. Also,
A pair of steps 10, 10 on which the rider R on the seat 9 puts his / her feet are provided on the upper surface side of the vehicle body frame 2.

The engine 3 is in the lower front of the seat 9 and in step 1
It is supported in front of 0 and 10 in the middle of the body frame 2 in the front-rear direction.

The front wheel device 4 has a pair of left and right front wheels 14, 14 supported on the front portion of the vehicle body frame 2, and a front axle 15 is connected to each of the front wheels 14. Also, the above left and right front wheels
The front wheel differential 17 is located in the center of the vehicle width direction between 14 and 14.
The front wheel differential device 17 is provided with both front axles 15 and 1.
The left and right front wheels 14, 14 are connected to each other by connecting the 5 to each other.

The front wheel differential device 17 is a known device and has a drive pinion 18 on the input side and a pair of left and right diff side gears 19, 19 on the output side, and each diff side gear 19 is connected to the front axle 15 respectively. Has been done.

Particularly, in the side view of FIG. 1, the front wheel differential device 17 is provided.
The lower surface position of the front portion of the vehicle body frame 2 corresponding to the position where is provided is located above the lower surface position of the middle portion of the vehicle body frame 2 supporting the engine 3 in the front-rear direction. Further, the front wheel differential device 17 and the engine 3 are disposed on the upper side of the vehicle body frame 2 as above.

The rear wheel device 5 has a pair of left and right rear wheels 20, 20 supported on the rear portion of the vehicle body frame 2, and these rear wheels 20, 20 are connected to each other by a rear axle 21. Further, there is provided a rear wheel gear unit 23 that enables power transmission from the engine 3 side to the rear axle 21.

The center axis of the crankshaft 12 of the engine 3 extends in the front-rear direction, and the front wheel differential gear 17 is mounted on the crankshaft 12 via a first power transmission device 13 and a second power transmission device 24. The first power transmission device 13 and the second power transmission device 24 are connected in an interlocking manner, and are attached to the outer surface of the crankcase on the side of the engine 3.

The second power transmission device 24 selectively switches the driving force transmitted from the engine 3 via the first power transmission device 13 to high speed or low speed, and transmits this to only the rear wheels 20, 20 side. Or, in addition to this, transmission to the front wheels 14, 14 side is also possible. Further, the second power transmission device 24 has a reverse rotation mechanism 25 capable of switching the driving force from the forward drive state to the reverse drive state of the vehicle.

The second power transmission device 24 will be described below.
The power transmission device 24 includes an input shaft 26 having an axial center extending in the front-rear direction and receiving the driving force of the engine 3 via the first power transmission device 13, and an input shaft 26 arranged on the same axial center as the input shaft 26 and in front of the input shaft 26. A front wheel output shaft 29, a rear wheel output shaft 31 having a shaft center extending in the front-rear direction and arranged in parallel with the input shaft 26 and the front wheel output shaft 29 in the vehicle width direction, and a front-rear direction. And an intermediate shaft 32 disposed above the input shaft 26 and the front wheel output shaft 29, and above the rear wheel output shaft 31. The input shaft 26 and the front wheel output shaft 29 can be engaged and disengaged by a dog clutch, and the first power transmission device 13, the input shaft 26, and the rear wheel output shaft can be engaged and disengaged.
The intermediate shaft 31 and the intermediate shaft 32 are linked to each other by a gear set.

A drive pinion 18 of the front wheel differential device 17 is interlockingly connected to a front end portion of the front wheel output shaft 29 via a front wheel propulsion shaft 27 which is a universal joint shaft. That is, the crankshaft 12 of the engine 3 is connected to the first power transmission device 13 and the input shaft 2
The front wheel differential device 17 is interlocked and coupled via the front wheel output shaft 29 and the front wheel propulsion shaft 27.

On the other hand, an input side of the rear wheel gear device 23 is interlockingly connected to a rear end portion of the rear wheel output shaft 31 via a rear wheel propulsion shaft 30 which is a universal joint shaft. That is, the above crankshaft 12
The rear wheels 20, 20 are interlocked with each other through the first power transmission device 13, the input shaft 26, the intermediate shaft 32, the rear wheel output shaft 31, the rear wheel propulsion shaft 30, and the rear wheel gear device 23. ing.

In the above case, the crankshaft 12 is arranged on one side of the vehicle body frame 2 in the vehicle width direction, while the same as above.
The front wheel output shaft 29 and the rear wheel output shaft 31 are disposed on the other side portion.

Further, the front wheel output shaft 29 and the rear wheel output shaft 31 are disposed between the front wheel 14 and the rear wheel 20 in the front-rear direction and further forward than the center thereof. And the output shaft 29 for the front wheels
Is disposed closer to the center of the vehicle body frame 2 in the vehicle width direction than the rear wheel output shaft 31.

In the above embodiment, the engine 3 which is a heavy object is located in the front part of the vehicle body, and the seat 9 for seating the similarly heavy rider R is located in the rear part of the vehicle body. Good balance is maintained. Further, since the assembly of the engine 3 and the first power transmission device 13 and the seat 9 on which the rider R is seated are located substantially in the center of the vehicle width direction, the weight balance in the vehicle width direction is also improved. To be kept.

(Effect of the Invention) According to the present invention, the lower surface position of the front portion of the vehicle body frame corresponding to the position where the front wheel differential device is provided is the lower surface position of the middle portion of the vehicle body frame supporting the engine in the front-rear direction. Since the front wheel differential and the engine are arranged on the upper side of the vehicle body frame, the upper middle portion of the body frame is lowered to some extent, and the center of gravity of the engine supported on this middle portion is positioned. It can be lowered to stabilize the running. Further, in this state, as described above, the lower surface position of the front portion of the vehicle body frame is raised, so that the front portion of the vehicle body frame collides with the road surface while traveling while aiming to lower the center of gravity. As a result, it is possible to prevent the front wheel differential device from being adversely affected.

Further, the crankshaft, the input shaft, the output shaft for the front wheels, the intermediate shaft, and the output shaft for the rear wheels of the engine are arranged so that their respective axial centers extend in the front-rear direction, and the one in the vehicle width direction of the body frame is arranged. While arranging the crankshaft on the side,
Since the front wheel output shaft and the rear wheel output shaft are arranged on the other side of the vehicle body frame, the weight balance in the vehicle width direction between the crank shaft and the front wheel output shaft and the rear wheel output shaft is improved. It is made even, and also in this respect, traveling can be stabilized.

Further, since the input shaft and the output shaft for the front wheels are arranged on the same axial center extending in the front-rear direction, the vehicle body becomes smaller in the vehicle width direction compared to arranging these in parallel in the vehicle width direction.
The rider can easily straddle the vehicle body.

Further, as described above, the input shaft and the front wheel output shaft are arranged on the same axis, and the rear wheel output shaft is arranged in parallel with the input shaft and the front wheel output shaft in the vehicle width direction, Since the intermediate shaft is arranged above the input shaft and the front wheel output shaft and the rear wheel output shaft, each of the input shaft, the front wheel output shaft, and the rear wheel output shaft is seen in a front view. The line connecting the hearts forms the base of the virtual triangle, and the axis of the intermediate shaft forms the top of the triangle. The center of gravity of the vehicle body is lowered, and stable running is achieved. Reserved.

Moreover, since the front wheel output shaft and the rear wheel output shaft form the base of the imaginary triangle as described above and are provided at the low position, the portions of the universal joint shafts connected to them are also at the low position. Therefore, in this respect as well,
Furthermore, the lowering of the center of gravity of the vehicle body is achieved.

Further, when the front wheel output shaft and the rear wheel output shaft are arranged between the front and rear wheels in the front-rear direction and in front of the center thereof, the front wheel output shaft is more than the rear wheel output shaft. Is also arranged on the center side of the vehicle body frame in the vehicle width direction, and the front wheel differential device is interlockingly connected to the front end side of the front wheel output shaft via a universal joint shaft.

Therefore, as described above, the front wheel output shaft is located on the front side of the vehicle body frame, and the front wheel output shaft approaches the front wheel differential device in the front-rear direction. The shaft can be brought closer to the front wheel differential device in the vehicle width direction without being hindered by the rear wheel output shaft, whereby the vehicle width between the front wheel differential device and the front wheel output shaft can be increased. The size of the direction can be reduced.

Therefore, the "angle" of the universal joint shaft for connecting the front wheel differential device to the front end portion of the front wheel output shaft can be reduced, and therefore, the power transmission from the front wheel output shaft to the universal joint shaft is smoothly performed. It

In the above case, the rear wheel output shaft is located on the outer side in the vehicle width direction with respect to the front wheel output shaft, and the angle of the universal joint shaft that connects the rear wheel to the rear wheel output shaft Is likely to grow.

However, as described above, since the rear wheel output shaft is located on the front side of the vehicle body frame, the rear wheel output shaft and the rear wheel are further separated from each other in the front-rear direction.

Therefore, as described above, even if the rear wheel output shaft is located on the outer side of the front wheel output shaft, the "angle" of the universal joint shaft can be made smaller. Power is smoothly transmitted to the universal joint shaft.

[Brief description of drawings]

1 shows an embodiment of the present invention, FIG. 1 is an overall schematic side view of a four-wheel drive vehicle, FIG. 2 is an overall schematic plan view of a four-wheel drive vehicle,
FIG. 3 is an overall schematic front view of a four-wheel drive vehicle. 1 ... 4-wheel drive vehicle, 2 ... Body frame, 3 ... Engine, 12 ... Crankshaft, 14 ... Front wheel, 17 ... Front wheel differential, 20 ... Rear wheel, 24 ... Second Power transmission device, 26 …… input shaft, 27 …… front wheel propulsion shaft (universal joint shaft), 29 …… front wheel output shaft, 30 …… rear wheel propulsion shaft (universal joint shaft), 31 ……
Rear wheel output, 32 ... Intermediate shaft.

Claims (1)

[Claims] 1. A front wheel having a pair of left and right front wheels supported by a front portion of a vehicle body frame, and a pair of left and right rear wheels supported by a rear portion of the vehicle body frame, wherein the left and right front wheels are disposed between these front wheels. For the front wheel through the input shaft, the output shaft for the front wheels, and the universal joint shaft on the crankshaft of the engine. On the other hand, the above crankshafts are connected to each other through the above input shafts, intermediate shafts, rear wheel output shafts, and universal joint shafts, and the respective rear wheels are linked together, and the front wheel output shafts and the rear wheel output shafts are connected. In a power transmission device for a straddle-type four-wheel drive vehicle, in which the front and rear wheels are arranged in the front-rear direction and in front of the center of the front and rear wheels, a vehicle body frame corresponding to the position where the front wheel differential device is provided. The lower surface position of the front part of the Of the crankshaft, the input shaft, the output shaft for the front wheels, the intermediate shaft for the front wheels, and the engine for the front wheels. The shaft and the rear wheel output shaft are arranged such that their axial centers extend in the front-rear direction, and the crankshaft is arranged on one side in the vehicle width direction of the body frame, while the other body frame The output shaft for the front wheels and the output shaft for the rear wheels are arranged on the side portions, the input shaft and the output shaft for the front wheels are arranged on the same axis, and the input shaft and the front wheels are arranged in the vehicle width direction. The output shafts for the rear wheels are arranged side by side on the output shaft, and the intermediate shaft is disposed above the input shaft and the output shaft for the front wheels and the output shaft for the rear wheels, and the output shaft for the front wheels is arranged at the rear. Located on the center side of the body frame in the vehicle width direction with respect to the wheel output shaft. A power transmission device for a saddle-ride type four-wheel drive vehicle in which the front wheel differential device is interlockingly connected to the front end side of a wheel output shaft via the universal joint shaft.