JPH0771955B2 - Rear-wheel drive for motorcycles - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rear wheel drive system for a motorcycle in which a rear wheel is supported by a cantilever type rear arm, and more particularly to a system for driving the rear wheel by a chain.

[0002]

2. Description of the Related Art A technique for supporting a rear wheel by a cantilever type rear arm in a motorcycle is disclosed in Japanese Utility Model Publication No. 53-532.
It is conventionally known as disclosed in Japanese Patent Laid-Open No. 37. As described above, the rear wheel suspension system using the cantilever type rear arm has a simple structure and is effective in terms of weight reduction of the vehicle, but since the rigidity of the rear arm is reduced, the external force acting on the rear arm is reduced as much as possible. It is necessary to take measures to reduce

[0003]

By the way, in a motorcycle in which a rear wheel supported by a cantilevered rear arm is driven by a chain, when the axial center of the rear arm and the extension direction of the drive chain are not aligned, the chain is pulled. Because of power,
Since a large bending force acts on the rear arm, appropriate reinforcement is required.

Therefore, an object of the present invention is to reduce the bending force acting on the rear arm as much as possible and reduce the strength required for the rear arm in a motorcycle in which the rear wheel supported by the cantilever type rear arm is driven by a chain. It is to provide a rear wheel drive device that can achieve a reduction in weight and a structure simplification.

[0005]

SUMMARY OF THE INVENTION In order to solve the above problems, according to the present invention, a base end of a cantilever type rear arm is rotatably supported on a rear portion of a vehicle body frame via a pivot shaft so that the cantilever type rear arm can be supported. In a motorcycle in which a rear wheel is supported at the other end, the cantilevered rear arm is a tie for the rear wheel.
The rear wheel and rear wheel drive
A sprocket for driving is placed across the cantilevered arm.
And a drive chain for connecting the output shaft of the sprocket and engine for rear-wheel drive supported on the rear end of the cantilevered rear arm, the pivot axis in a cantilever rear arm front end adjacent to the side of the vehicle body frame And the pivot shaft of the cantilever type rear arm
On the inner surface of the rear part of the body frame that supports the pivot shaft.
The feature is that they are arranged adjacent to each other.

[0006]

[Operation] A drive chain connecting between a rear wheel drive sprocket supported on the rear end of the cantilevered rear arm and the output shaft of the engine is connected to the pivot shaft at the front end of the cantilevered rear arm adjacent to the side surface of the vehicle body frame. Since it passes over the fitting portion of No. 2, even if a strong tension driving the rear wheel is applied between the output shaft and the driven sprocket, a large bending force does not act on the rear arm.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 showing a motorcycle to which the present invention is applied
In the figure, 1 is a body frame, 2 is an engine, and 11 and 1.
2 is a front arm, 13 is a steering plate, 1
5 is a front wheel, 21 is a rear arm, 26 is a pivot shaft, 31
Is a rear wheel, 41 is a sprocket, and 42 is a chain.

A V-type engine 2 is jointly supported between the body frames 1 and 1, a rear body 3 forming a seat cowl is jointly supported at the rear portion of the body frame 1, and a seat 4 is placed on the rear body 3 and A front body 5 is connected to the front part of the rear body 3. 6 is a handle. A steering plate 13 is supported on the front portion of the vehicle body frame 1 via a front upper arm 11 and a front lower arm 12, and an axle 16 of front wheels 15 is supported on the steering plate 15. 17
Is a shock absorber for the front wheels.

A rear arm 2 is provided at the rear of the body frame 1.
1 is rotatably supported by a pivot shaft 26.
That is, the base portion of the rear arm 21 has a fork shape, and the left and right fitting portions 23, 23 of the fork portion 22 are adjacent to the inner side surfaces of the rear portions of the vehicle body frames 1, 1 via the pivot shafts 26, 26. It is pivotally supported.

The rear arm 21 includes an intermediate portion 24 and a rear wheel 31.
Avoid the tire 32 part and bend once to one side, rear part 2
5 is formed to be closer to the vehicle width center line N and further bent, and the rear portion 25 supports the axle 36 of the rear wheel 31 in a cantilevered manner. 37 is a shock absorber for rear wheels. A driven sprocket 41 is mounted on an end opposite to the rear wheel 31 with the rear arm rear portion 25 of the axle 26 interposed between the driven sprocket 41 and a drive sprocket provided on the output shaft of the engine 2 as is known. Drive chain 4
2 is hung.

The wheel hub 33 of the rear wheel 31 bulges to the side opposite to the sprocket 41, and a brake disc 46 is arranged between the rear wheel 31 and the rear arm rear portion 25.
In the above embodiment, the chain 42 that connects the driven sprocket 41 attached to the axle 36 supported on the rear portion 25 of the rear arm 21 that supports the rear wheel 31 in a cantilevered manner and the output shaft of the engine 2 is the vehicle body frame. The fork portion 22 of the rear arm 21 adjacent to the inner side surface of the first arm 1 passes over one fitting portion 23 with the pivot shaft 26.

As described above, according to the present invention, for rear wheel drive
Drive that connects between the sprocket and the output shaft of the engine.
The moving chain at the front end of the cantilevered rear arm.
The output shaft and sprocket
Cantilever type even if strong tension driving the rear wheels acts between
It is possible to prevent a large bending force from being generated on the rear arm.
Wear. Also, according to the present invention, the pivot of the cantilever type rear arm is provided.
Rear part of the vehicle body frame supporting the pivot shaft
Since it is placed adjacent to the inner surface of the
The bending mode applied from the rear arm side and the body frame side.
Minimum size, increasing the strength of the pivot axis
It is not necessary and the weight can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic side view of a motorcycle to which the present invention is applied.

FIG. 2 is a bottom view showing a state in which a power unit and fittings are removed.

[Explanation of symbols]

1 ... Body frame, 2 ... Engine, 21 ... Rear arm,
23 ... Pivot shaft fitting portion, 26 ... Pivot shaft, 31 ... Rear wheel, 41 ... Sprocket, 42 ... Chain.

Claims (1)

[Claims] 1. A motorcycle in which a base end of a cantilever type rear arm is rotatably supported on a rear portion of a body frame via a pivot shaft, and a rear wheel is supported on the other end of the cantilever type rear arm. The cantilevered rear arm is the rear wheel
Avoid the ear part and bend outward in an arc shape,
Place the drive sprocket with the cantilever arm in between.
Location, and said driving chain for connecting the output shaft of the sprocket and engine for rear-wheel drive supported on the rear end of the cantilevered rear arm, wherein the cantilevered rear arm front end adjacent to the side surface of the body frame pivot The pivot shaft fitting of the cantilevered rear arm is made to pass through the fitting part with the shaft.
Inner surface of the rear part of the body frame that supports the pivot shaft at the joint
A rear-wheel drive system for a motorcycle, wherein the rear-wheel drive system is arranged adjacent to the .