JPS6029383A - Motorcycle for desert travelling - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motorcycle for running on rough terrain, in which a rear wheel equipped with wide low-pressure tires is supported by a swing arm so as to be movable up and down.

To make driving on rough terrain easier, the rear wheels are fitted with wide, low-pressure tires (
There are motorcycles equipped with so-called balloon tires. In this type of vehicle, a so-called rigid type rear wheel suspension system, in which the rear wheel axle is fixed to the vehicle body frame, is used because the tires themselves have a large cushioning effect. However, in order to further improve the ability to travel on rough roads, it is preferable that the rear wheel suspension be of a shock-absorbing type that can be moved up and down.

In this case, since the tires are wide, depending on the person installing the shock absorbing unit, the width of the vehicle body frame must be widened to support one end of the shock absorbing unit, which may make it difficult to sit in the driver's seat. A problem arises.

The present invention was developed in view of these circumstances, and despite the fact that a wide low-pressure tire having at least approximately the same width as the frame is mounted on the rear wheel held by a swing arm extending rearward from the frame, An object of the present invention is to provide a motorcycle for running on rough terrain, which can improve running performance on rough roads without deteriorating seating comfort of a driver's seat.

In order to achieve this objective, the present invention arranges a buffer unit near the center of the vehicle body. In other words, the rear wheel is supported in a vertically movable manner by a swing arm that extends rearward from the vehicle frame.
In the rough terrain motorcycle in which the rear wheel is equipped with a wide low-pressure tire having at least the same width as the frame, a buffer unit provided between the frame and the swing arm is disposed near the center of the vehicle body. The present invention will be described in detail below based on the illustrated embodiments.

Fig. 1 is a side view of one embodiment of the present invention, Fig. 2 is a plan view showing the rear wheel drive mechanism, Fig. 3 is a right side view showing a part of the mechanism, and Fig. 4 is a rear wheel suspension system. FIG.

In Figure 1.4, numeral 10 is a cradle type frame,
Steering shaft cylinder 12. Main tube 14. down tube 1
6. Lower tube 18, 18. Seat pillar tube 20, 20. Seat rail 22゜Back tube 24
．． 24 mag. In Figure 1, 26 is the front fork, 28 is the front wheel equipped with wide low-pressure tires, 30 is the steering handle,
32 is a fuel tank, and 34 is a driver's seat. The engine 36 is mounted on the lower arm 18. At the bottom of the seat pillar tube 20.20 there is a bracket 38°38
is fixed.

Reference numeral 40 denotes a swing arm, which has a pair of left and right arms, the distance between which widens at the rear, and between which a rear wheel 42 equipped with a wide low-pressure tire is rotatably supported. Second
In the figure, 44 is a rear wheel side sprocket that drives this rear wheel 42, and 46 is a brake. The front part of the swing arm 40 is made narrow.

Its front end is held by a pivot shaft 4B supported by the brackets 38 and 38 so as to be swingable in the vertical direction.

Note that the rear end portion of the engine 36 is also supported by this pivot shaft 48 .

An intermediate shaft 50 is inserted laterally into a narrow portion of the swing arm 40 behind the pivot shaft 48 .

It is rotatably supported by bearings 52, 54 (FIG. 2). Reference numerals 56 and 56 denote a pair of left and right footrests, which are fixed to the lower part of the seat pillar tube 20 so as to protrude outward.

Subrockets 60 and 62 are fixed to the right ends of the output shaft 58 (FIGS. 2 and 3) of the engine 36 and the intermediate shaft 50, and both have a first shaft passing through the inside of the seat pillar tube 20.
A chain 64 is wrapped around it. This chain 64
passes above and below the guide roller 66 rotatably supported by the pivot shaft 48. The left end of the intermediate shaft 50 protrudes outward from the left seat pillar tube 20, and a sprocket 68 is fixed to the tip thereof. A second chain 70 is wound around this sprocket 68 and the sprocket 44 of the rear wheel 42. Therefore, the rotational output of the engine 36 is transferred to the intermediate shaft 50 by the first chain 64.
is further transmitted to the rear wheel 4 by the second chain 70.
2 can be conveyed.

Reference numeral 72 designates a buffer unit disposed near the center of the vehicle body, the front end of which is pivotally supported by the main tube 14, and the rear end pivotally attached to one end of a lever 74 bent at a substantially right angle. The other end of the lever 74 is attached to both seat pillar tubes 20.
It is pivoted between 20. Further, the intermediate portion of the lever 74 is connected to the swing arm 40 by a bushing link 76.

In the above embodiment, the rotational output of the engine 36 is transmitted to the intermediate shaft 5o via the first chain 64, and the rotation of the intermediate shaft 50 is transmitted to the second chain 70? Through! It is transmitted to the wheel 42. Further, when an upward impact is applied to the rear wheel 42 from the road surface, the swing arm 40 swings about the pivot shaft 48, the bushing link 76 pushes the lever 74, and the shock absorbing unit 72 is compressed. The buffer unit 72 is attached to the rear wheel 42
It is located near the center of the vehicle body diagonally above and in front of the
4. Since the link 76 is also arranged in front of the rear wheel 42, there is no need to widen the frame width to support the upper end of the shock absorbing unit, unlike when shock absorbing units are arranged on both sides of the rear wheel 42. This makes it possible to reduce the frame width.

Note that the intended purpose of the shock absorbing unit of the present invention can be achieved by disposing it at an appropriate position near the center of the vehicle body from the front to the upper side of the rear wheels 42, and is not limited to the position of the embodiment. Further, the shock absorbing unit and the swing arm may be linked to each other via a link, or may be directly connected to each other.

As described above, in the present invention, since the shock absorbing unit is disposed near the center of the vehicle body, there is no need to widen the frame width as in the case where shock absorbing units are provided on the left and right sides of the rear wheels. Therefore, the width of the driver's seat does not become wide, and seating comfort can be improved.

[Brief explanation of the drawing]

FIG. 1 is a left side view of an embodiment of the present invention, FIGS. 2 and 3 are a plan view and right side view of a portion thereof, and FIG. 4 is a perspective view showing a rear wheel suspension mechanism. 10...Frame, 40...Swing arm. 42...Rear wheel, 72...Buffer unit. Patent applicant Yamaha Motor Co., Ltd. Agent Patent attorney Yama 1) Yu Moon

Claims (1)

[Claims] In the motorcycle for running on rough terrain, the rear wheel is vertically movably supported by a swing arm extending rearward from a frame of the vehicle body, and the rear wheel is equipped with a wide low-pressure tire having at least approximately the same width as the frame. A motorcycle for traveling on rough terrain, characterized in that a buffer unit provided between a frame and a swing arm is arranged near the center of the vehicle body.