JPH038996B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement of a rear wheel suspension system for a motorcycle that employs a so-called progressive link mechanism (hereinafter referred to as "Prolink").

As shown in FIG. 3, the front part of the swing arm 132 is pivotally supported at the front end O at the lower part of the vehicle body frame 120, and the rear wheel 136 is pivotally supported at the rear end, and the vehicle body frame 1
Hydraulic shock absorber 142 pivoted at the upper end on the upper part of 20
A rear wheel suspension system for a motorcycle in which the lower end of the rear wheel is connected to the lower end of the rear wheel via a prolink 144 is in practical use.

Specifically, one end of one bellcrank-shaped link 146 constituting the pro link 144 is pivotally attached to the front part of the swing arm 132, and a corner part 146a forming an intermediate part is attached to the shock absorber 14.
2, and one end of the other link 145 is pivoted A to a bracket 129 fixed to the lower part of the vehicle body frame 120, so that the other end of the link 145 and the other end of the bell crank type link 146 are connected to each other. Pivot B
It is connected.

That is, the pivot connection point B of both links 145 and 146
is the pivot point O of the swing arm 132 and the pivot point C of the arm 132 with the one link 146.
Because it was placed below the straight line () connecting
The pro link 144 protrudes rearward or downward from the body frame 120, and therefore the rear wheel 136
As shown in the figure, the space S between the rear pipe 123 that leans backward and the rear wheel 136 becomes large. For this reason, it is not possible to bring the rear wheel 136 closer to the vehicle body frame 120 or to increase the size of the rear wheel 136, and the length (abbreviation) of the swing arm 132 is inevitably reduced.
However, it was also somewhat long, and there was a limit to how short the wheelbase could be shortened.

Furthermore, since the prolink 144 protrudes backward or downward from the vehicle body frame 120, the shock absorber 142
As shown in the figure, the shock absorber 142 has to be placed behind the center pipe 129 which leans forward, and therefore the shock absorber 142 cannot be placed forward, that is, close to the center of gravity of the vehicle. Improvement is desired.

The present invention has been made in view of the above circumstances.
The purpose of this is to shorten the swing arm and shorten the wheelbase by particularly devising the arrangement of the Pro Link, as well as placing the shock absorber further forward to centralize heavy loads. Another object of the present invention is to provide a rear wheel suspension system for a motorcycle that achieves the following.

In order to achieve such an object, the present invention fixes a plate that protrudes forward to the lower part of a rear pipe that is tilted backwards that constitutes the vehicle body, and attaches the front end of the swing arm to the lower part of the plate, and the front end of one of the links to the upper part of the plate. One end of each link is pivotally supported, one end of the other link is pivotally connected to the lower end of the shock absorber, the intermediate part is pivotally connected to the front part of the swing arm, and the pivot connection point of both links is
Behind the straight line that connects the shock absorber's pivot point on the vehicle body side and the pivot point with the other link, and above the straight line that connects the swing arm's pivot point on the vehicle body side and the pivot point with the one link above. The link mechanism is located in front of the rear pipe.

A preferred embodiment of the present invention is shown below in Figures 1 and 2.
This will be explained in detail based on the figures.

FIG. 1 is a schematic side view of the motorcycle, and FIG. 2 is an enlarged side view of the rear wheel suspension.

The motorcycle 1 in this embodiment is an off-road type, and a steering stem 3 is supported in a steerable manner on a head pipe 2 fixed to the front end of a body frame 20, and upper and lower bridges 4, which are integral with the stem 3,
The upper parts of front forks 7, 7 which pivotally support a front wheel 6 at their lower ends are fixed to the top bridge 4, and a handle pipe 8 is fixed to the top bridge 4.

The vehicle body frame 20 includes left and right main pipes 21, 21 extending rearward from the upper part of the head pipe 2, and one or two main pipes 21, 21 extending rearward from the lower part of the head pipe 2 (in the embodiment). 1) down pipe 22, left and right rear pipes 23, 23 that are connected to the rear end of the main pipe 21 at the middle part and tilt backward, and left and right rear pipes 23, 23 that are fixed to the lower half of this rear pipe 23 and protrude forward. It consists of bottom plates 24, 24, and left and right seat pipes 25, 25 that extend rearward from the middle part of the main pipe 21, are supported at the middle part by the rear pipe 23, and further extend rearward.

A mount bracket 26 is fixed to the lower part of the down pipe 22 of the vehicle body frame 20, and the engine 10 is mounted between the bracket 26 and the bottom plates 24, 24, and the lower part of the engine 10 is covered with an under cover 27. In addition, between the left and right main pipes 21, 21, an air cleaner 11, a contube 12, a carburetor 13, and a fuel tank 14 are arranged in this order from the front, and these are covered from above with a cover 15. Seat pipe 25, 25 on the rear of 15
A sheet 16 is placed on top.

Furthermore, a swing arm 32 is pivoted at its front end to a pivot shaft 31 that is horizontally suspended between the lower portions of the left and right bottom plates 24, 24.
is formed by connecting a cross pipe 34 between the front parts of left and right pipe members 33, 33, and an axle 37 of a rear wheel 36 is pivotally supported at the rear end of this swing arm 34, and the axle 37 and engine 10 A chain and sprocket mechanism 17 is installed in the well-known manner.

On the other hand, a bracket 28 is fixed to the rear of the joint between the main pipe 21 and the seat pipe 25, and a hydraulic shock absorber 42 is pivotally supported at the upper end of a pivot shaft 41 that extends horizontally between the left and right brackets 28, 28. .

A pivot shaft 43 is horizontally mounted between the upper parts of the left and right bottom plates 24, 24, and this pivot shaft 4
3, one end of one tension rod 45 constituting the pro link 44 is pivotally supported A, and one end of the other cushion arm 46 is pivotally connected B to the other end of this tension rod 45. The cushion arm 46 has a bell crank shape, and a corner 46a at the middle thereof.
, the cross pipe 34 of the swing arm 32
The cushion arm 46 is pivotally connected to a bracket 35 projecting above, and the other end of the cushion arm 46 is connected to the buffer 42.
Pivotally attached D to the lower end of.

Thus, the pivot connection point B between the tension rod 45 and the cushion arm 46 forming the pro link 44
is behind the straight line () connecting the pivot point E of the shock absorber 42 on the vehicle body side and the pivot point D of the cushion arm 46, and is located between the pivot point O of the swing arm 32 on the vehicle body side and the pivot point D of the cushion arm 46. It was arranged above the straight line () connecting the pivot point C of the

In this way, the pro link 44 is arranged between the left and right bottom plates 24, 24, that is, the rear pipe 23
Since the Prolink 44 is arranged in front of the shock absorber 42 and close to the rear side of the shock absorber 42 to make the Prolink 44 compact, the rear wheel 36 can be brought closer to the rear pipe 23, and the rear wheel 36 and the rear pipe 23 can be connected to each other as shown in the figure. The space S of the wheelbase (W) can be reduced, and the length of the swing arm 32 (omitted) can be shortened by this amount, which is advantageous for cars such as trial cars that want to minimize the wheelbase (W). B) can be shortened.

Furthermore, since the Prolink 44 is disposed within the vehicle body frame 20 and the shock absorber 42 is disposed in front of it as described above, the shock absorber 42 can be disposed forward, that is, close to the center of gravity of the vehicle. This allows for further centralization of objects and therefore improves the handling of the vehicle, which is particularly advantageous for trial vehicles.

As in the embodiment, the bell crank-shaped cushion arm 46 is pivotally attached to the swing arm 32 side at its angle 46a, and the tension rod 45 disposed upward is pivotally attached to one end of this arm B, so that the rear wheel axle 37 The stroke ratio of the shock absorber 42 to the stroke of the lever ( ) is improved by the amplified ratio of the lever ( ) to the lever ( ). As a result, the spring constant of the buffer 42 can be lowered, and the force acting on each pivot point A to D of the Prolink 44 is also reduced.As a result, the Prolink 44 can be made lighter and more compact, thereby saving space. It is also possible to improve the degree of freedom in design, such as by making effective use of the materials.

As is clear from the above description, according to the present invention, the prolink can be placed within the vehicle body frame and the shock absorber can be placed in front of it, so the swing arm can be shortened and the wheelbase can be shortened.
Furthermore, concentration of heavy objects can also be achieved.

[Brief explanation of drawings]

FIG. 1 is a schematic side view of a motorcycle to which the present invention is applied, FIG. 2 is an enlarged side view of a rear wheel suspension system which is a main part thereof, and FIG. 3 is a side view showing a conventional example. In the drawings, 1 is a motorcycle, 20 is a body frame, 24 is a plate, 32 is a swing arm, 3
6 is a rear wheel, 42 is a shock absorber, and 45 and 46 are links.

Claims (1)

[Claims] 1. The front end is pivoted at the lower part of the vehicle body, and the rear wheel 3 is mounted at the rear end.
The front part of the swing arm 32, which has a swing arm 6 pivoted thereon, and the lower end of a shock absorber 42, whose upper end is pivoted E on the upper part of the vehicle body, are connected via a link mechanism 44 whose one end is pivoted A on the vehicle body side. In a rear wheel suspension system for a motorcycle, a plate 24 protruding forward is fixed to the lower part of a rear pipe 23 in a backward-inclined shape constituting the vehicle body, and the front end of the swing arm 32 is pivoted to the lower part of the plate 24. , one link 4 constituting the link mechanism 44 on the upper part of the plate 24
5 is pivoted A, the other end of the other link 46 is pivoted to the lower end of the shock absorber 42, and the intermediate part is pivoted D and C to the front part of the swing arm 32, respectively, and both links 45, 46 is pivotally connected to the other end at one end B, and furthermore, the pivot connection point B is connected to the rear of the straight line DE connecting the vehicle body side pivot point E of the shock absorber 42 and the pivot point D of the other link 46. And, the vehicle body side pivot point O of the swing arm 32 and the swing arm 32
The link mechanism 4 is positioned above the straight line OC connecting the other link 46 and the pivot point C.
4 is disposed in front of the rear pipe 23.