JPS6251793B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention primarily relates to a rear wheel suspension system for motorcycles and other two-wheeled vehicles.

Conventionally, in this type of two-wheeled vehicle, a type in which a support shaft is installed horizontally in the middle of a body frame having a front wheel and a rear wheel, and a swing arm extending forward from the rear wheel is pivotally supported by this is known. In this case, since the length for attaching the arm to the vehicle body frame cannot be increased, it has been considered difficult to use this as a suspension spring even if a torsion bar is disposed at this location.

The object of the present invention is to provide a device that eliminates such inconveniences, and includes a swing arm that has a support shaft horizontally disposed in the middle of a vehicle body frame having front wheels and rear wheels, and extends forward from the rear wheels. In the case of a type in which the support shaft is pivotally supported by the frame, the support shaft is fixed to the frame at one end and extends to the other side, and the other end is connected to the bar by a spline or the like. A torsion pipe is connected to the outer periphery and extends to the one side, and the swing arm is engaged with the end of the one side of the pipe by a spline or the like.

An example of implementing the present invention will be explained with reference to the attached drawings.

In the drawing, 1 indicates the vehicle body frame, and the frame 1
As clearly shown in FIG. 1, the vehicle has a front wheel 2, a rear wheel 3, and an engine 4 located in the middle thereof, and is configured as a motorcycle or other two-wheeled vehicle as a whole. In the drawing, numeral 5 indicates the seat for the passenger on the upper side, numeral 6 indicates the fuel tank in front of it, and numeral 7 indicates the steering handle in front of it.

The body frame 1 is provided with a support shaft 8 extending laterally in the middle thereof, and the swing arm 9 extending forward from the rear wheel 3 is pivotally supported on the shaft 8 at its front end and swings up and down. It was made to be able to move freely.

Although the above is not particularly different from the conventional one, according to the present invention, the torsion bar 10 centered on the support shaft 8
It has a double structure with a torsion pipe 11 on its outer periphery. More specifically, as shown in FIG. 2, for example, the torsion bar 10 has its left end 10a fixed to the vehicle body frame 1, extends to the right in the diagram, and extends its end 10b to the vehicle body frame 1. 1, the torsion pipe 11 has its right end 11a in the figure splined to the bar 10, extends to the left in the figure, and has its end 11b mounted on the bar 10. The swing arm 9 is rotatably supported by the swing arm 9.
are the bosses 9b, 9 at the front ends of the left and right arm pieces 9a, 9a.
The bush 16 is fitted onto the outer periphery of the bush 16 at b.
17 and is rotatably supported via needle bearings 13, 13, and the boss 9b on the left side in the drawing.
The spline engagement 14 is made to the outer periphery of the end portion 11b described above.

Thus, the thrust load in the left direction is supported by the body frame 1 from the boss 9b via the thrust bush 16, similar to the conventional one, but the thrust load in the right direction is supported by the torsion pipe from the boss 9b. 11 and a bush 17, it is supported by the vehicle body frame 1. The above-mentioned spline engagements 12 and 14 may be of a type that engages with the boss 9b or the end 11a of the torsion pipe using engagement means such as a key or a turret pin. Furthermore, the torsion pipe 11 is located at the left end 1 in the drawing.
A torsion force is applied to the torsion bar 1b, and through this, the torsion bar 10 is
Torsion bar 1
0 has its working length almost doubled by the pipe 11, so that it functions well as a suspension spring.

In the case shown in the drawings, if the spring action is insufficient, an air damper 15 is further provided on the upper surface of the arm 9 to compensate for this. That is, an intermediate member 9c that interconnects the left and right arm pieces 9a, 9a of the arm 9.
An air damper 15 is interposed between the upper surface of the vehicle body frame 1 and the upper surface of the vehicle body frame 1 to further improve the suspension characteristics. The air damper 15 can also be of a type equipped with a coil spring, if necessary.

To explain its operation, as the swing arm 9 swings up and down, the torsion pipe 11 sequentially applies a torsion force to one end of the torsion pipe 11 and the other end of the torsion bar 10 via this. The torsion bar 10 is connected to the torsion pipe 1.
1, its working length is almost doubled and it functions well as a suspension spring.

In this way, according to the present invention, the support shaft that pivotally supports the swing arm is connected to the central torsion bar,
It is constructed with a torsion pipe on the outer periphery and functions as a suspension spring, and has the effect of eliminating the above-mentioned conventional disadvantages.

[Brief explanation of the drawing]

FIG. 1 is a side view of an example of a motorcycle equipped with the device of the present invention, FIG. 2 is an enlarged plan view with a portion of its essential parts cut away, and FIG. 3 is a cross-sectional view taken along the line -2. DESCRIPTION OF SYMBOLS 1...Vehicle frame, 2...Front wheel, 3...Rear wheel, 8...Support shaft, 9...Swing arm, 10
...Torsion bar, 11...Torsion pipe.

Claims (1)

[Claims] 1. In a vehicle body frame having a front wheel and a rear wheel, a support shaft is installed horizontally in the middle of the body frame, and a swing arm extending forward from the rear wheel is pivotally supported by the support shaft, and the support shaft is attached to one end of the vehicle body frame. a central torsion bar fixed to the frame and extending to the other side;
A torsion pipe on the outer periphery is engaged with the bar at the other end by a spline or the like and extends to the one side, and the swing arm is engaged to the one end of the pipe by the spline or the like. A rear wheel suspension system for two-wheeled vehicles.