JP2602067Y2 - Rear shock absorber for motorcycle - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a motorcycle rear wheel shock absorber using a rotary damper.

[0002]

2. Description of the Related Art Conventionally, as a shock absorbing means for absorbing the vertical movement generated at the rear wheel of a motorcycle using a rotary damper, for example, two mountings as disclosed in Japanese Patent Application Publication No. 173778/1988 are used. Means are known.

One of them is to dispose a rotary damper at a pivot portion of a swing arm supporting a rear wheel to a body frame, and attach a housing of the rotary damper to the swing arm side.

On the other hand, the rotor shaft of the rotary damper is fixed to the vehicle body frame side, whereby a relative movement is given between the housing of the rotary damper and the rotor shaft with the swinging motion of the swing arm to perform a damping action. That is, mounting means is used in which the so-called rotary damper itself is used as a pivot axis of the swing arm with respect to the vehicle body.

Another means is to fix the housing of the rotary damper at a position above the pivot axis of the swing arm with respect to the body frame.

The rotor shaft of the rotary damper is linked to a swing arm via an interlocking mechanism including an arm and a link, and the swing motion of the swing arm is rotated by the link and the arm about the rotor shaft of the rotary damper. In this case, a so-called attachment mechanism using a link mechanism is employed, which transmits the force as a damping effect.

[0007]

In the above-mentioned prior art, since the former mounting means is provided with a rotary damper at the pivoting portion of the swing arm, the swing arm is attached to the rotary damper. And the swinging motion having the same angle as that of the rotary damper can be given, and the stroke of the rotary damper cannot be sufficiently taken, so that there is a disadvantage that the buffering efficiency is low.

On the other hand, according to the latter mounting means, the swinging motion of the swing arm can be enlarged and transmitted to the rotor shaft of the rotary damper by the ratio of the distance from the swing center of the swing arm to the link connection point and the arm length. Therefore, the inconvenience as described above can be solved.

However, on the other hand, since the swinging motion of the swing arm must be indirectly transmitted to one side of the rotor shaft via the arm by the link, the swing arm swings due to the misalignment of the link and the arm. The motion is input as an offset load to the rotor shaft, and as a result, the rotary damper is subject to uneven wear or twisting, which inevitably causes a problem in the intended damping characteristics and a problem in durability.

Accordingly, an object of the present invention is to provide a motorcycle rear wheel shock absorber using a rotary damper which can ensure a sufficient stroke and is excellent in terms of damping characteristics and durability.

[0011]

Means for Solving the Problems In order to achieve the above object, the means of the present invention is provided by interposing a rear wheel between a vehicle body frame and a swing arm pivotally attached to the vehicle body frame. In a motorcycle rear wheel shock absorber using a rotary damper that buffers vertical movement, a rotor shaft of the rotary damper is fixed to a body frame via a bracket, and the rear surface of the housing of the rotary damper is swingable to a swing arm via a link. , And one of a cushion rubber and a stopper which abuts the cushion rubber is attached to the vehicle body frame and the front surface of the housing, respectively.

[0012]

According to the above construction, the swinging motion of the swing arm supporting the rear wheel of the motorcycle is based on the distance between the swing center of the swing arm and the link connection point and the link connection from the rotor shaft of the rotary damper. It is enlarged by the ratio of the distances of the points and transmitted to the housing of the rotary damper.

Therefore, by appropriately selecting these ratios, the stroke of the rotary damper can be freely set, and a rear wheel shock absorber of a motorcycle with a high shock absorbing efficiency can be obtained.

Moreover, since the swinging motion of the swing arm is transmitted directly to the housing on the rotary damper side through the link, the swinging motion of the swing arm is not input to the rotary damper side as an offset load. As a result, uneven wear and twisting of the rotary damper do not cause a problem in the intended damping characteristics and cause no problem in durability.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1 and FIG. 2, a swing arm 2 (rear wheel support portion is not shown) for supporting a rear wheel extends rearward from the body frame 1 of the motorcycle. Has one end swingably connected to the vehicle body frame 1 by a swing arm shaft 3.

A rotary damper 4 for attenuating the swinging motion of the swing arm 2 is disposed so as to face the cross beam 1a of the body frame 1, and both ends of the rotor shaft 5 of the rotary damper 4 are connected to the body frame. 1 cross beam 1
The rotary damper 4 is supported on the vehicle body frame 1 by being fitted to the brackets 6 and 7 provided on the frame a.

In the above description, one end of the rotor shaft 5 is
As shown in FIG. 5, the rotor shaft 5 of the rotary damper 4 is non-rotatably fixed to the vehicle body frame 1 by a screw 9 via a rotation preventing mechanism including a spline 8 and the like. is there.

On the other hand, a bracket 11 is provided on the rear surface of the housing 10 of the rotary damper 4, and one end of a link 12 is swingably connected to the bracket 11 by a shaft 13.

The other end of the link 12 is connected to a bracket 14 provided on the cross beam 2 a of the swing arm 2 by a shaft 15.
It was connected rotatably.

Thus, the rotary damper 4 fixes the rotor shaft 5 to the vehicle body frame 1 and
0 is connected between the vehicle body frame 1 and the swing arm 2 with the link 0 connected to the swing arm 2 by the link 12.

As is apparent from FIG. 1, the front surface of the housing 10 of the rotary damper 4 and the cross beam 1a of the body frame 1 are brought into contact with each other at the upper and lower ends of the swing arm 2 by abutment. Stoppers 16 and 17 for restricting movement and cushioning rubbers 18 and 19 are attached.

In this embodiment, the stopper 1
Although the wheels 6 and 17 are provided on the housing 10 side of the rotary damper 4 and the cushioning rubbers 18 and 19 are provided on the side beams 1a of the vehicle body frame 1, it goes without saying that these may be mounted in reverse.

Next, the operation of the motorcycle rear wheel shock absorber configured as described above will be described.

When a vertical relative displacement occurs between the vehicle body and the rear wheels during the running of the motorcycle, the swing arm 2 swings about the swing arm shaft 3 with respect to the vehicle body frame 1. The housing 10 of the rotary damper 4 is swung around the rotor shaft 5 through the link 12.

At this time, the swinging motion of the swing arm 2 is based on the distance L between the swing center of the swing arm 2 and the connection point of the link 12 and the connection of the link 12 from the axis of the rotor shaft 5 in the rotary damper 4. It is transmitted to the housing 10 of the rotary damper 4 after being enlarged by the ratio “L / S” to the distance S of the point.

As a result, the housing 10 of the rotary damper 4 pivots largely around the rotor shaft 5 and is divided into a partition wall on the housing 10 side and a vane on the rotor shaft 5 side, as is generally well known. The compressed hydraulic oil chambers are compressed and expanded, and flow resistance is applied to the hydraulic oil flowing between these hydraulic oil chambers to generate damping force.

From this, it is possible to freely set the operation stroke of the rotary damper 4 by appropriately selecting the above-mentioned ratio "L / S" and efficiently generate the damping force characteristic.

Moreover, in addition to the above, the swing arm 2
Is transmitted directly to the housing 10 of the rotary damper 4 through the link 12, so that the swinging motion of the swing arm 2 is transmitted to the housing 10 of the rotary damper 4.
As a result, the rotary damper 4 is prevented from being subjected to uneven wear, twisting, or the like, thereby causing the desired damping characteristics to be out of order or reducing the durability.

In the above case, when the swing arm 2 attempts to swing beyond the upper moving end or the lower moving end, the stopper 16 interposed between the housing 10 and the body frame 1 and the cushion rubber 18 or The stopper 17 and the cushioning rubber 19 abut against each other to limit the overstroke of the swing arm 2 while absorbing the shock generated at that time.

[0031]

As described above, according to the invention, as a motorcycle rear wheel shock absorber using a rotary damper, a sufficient stroke is secured by a link connection method, and the rotary damper and the swing are connected. By connecting the arms with one link, it is possible to obtain excellent damping characteristics and durability. Further, as described above, since only one link is required to connect the rotary damper and the swing arm, the configuration is simplified, and the assembling is facilitated, so that the supply can be performed at a low cost. Moreover, in addition to the above, since the swinging motion of the swing arm is directly transmitted to the housing of the rotary damper through the link, the swinging motion of the swing arm is not input to the housing of the rotary damper as an offset load,
As a result, there is no possibility that uneven wear or twisting of the rotary damper acts on the rotary damper, causing the desired damping characteristics to be deviated or the durability to be reduced. Further, in the above, when the swing arm attempts to oscillate beyond the upper moving end or the lower moving end, the stopper interposed between the housing and the vehicle body frame and the cushioning rubber or the stopper and the cushioning rubber collide with each other. Then, the overstroke of the swing arm is limited while absorbing the shock generated at that time.

[0032]

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view of an essential part showing an embodiment of a motorcycle rear wheel shock absorber according to the present invention.

FIG. 2 is a rear view of the same as seen from the rear.

FIG. 3 is a partial longitudinal sectional front view showing an example of mounting a rotor shaft in a rotary damper.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Body frame 2 Swing arm 4 Rotary damper 5 Rotor shaft 10 Housing 12 Link

Claims (1)

(57) [Scope of request for utility model registration] A motorcycle rear wheel shock absorber utilizing a rotary damper interposed between a vehicle body frame and a swing arm pivotally attached to the vehicle body frame to absorb vertical movement of a rear wheel, The rotor shaft of the rotary damper is fixed to the body frame via a bracket, the rear surface of the housing of the rotary damper is swingably connected to the swing arm via a link, and a cushion rubber is provided on the body frame and the front surface of the housing. A rear wheel shock absorber for a motorcycle, wherein one of the stopper and the stopper which abuts on the shock absorbing rubber is attached.