JPS6328837B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rear wheel suspension system for a motorcycle or the like.

Hydraulic shock absorbers are generally used in rear wheel suspension systems for motorcycles and the like. This hydraulic shock absorber includes a shock absorbing spring and a hydraulic damper. When such a hydraulic shock absorber is used in a rear wheel suspension system such as a motorcycle, the strength of the shock absorbing spring and the damping force of the damper are determined based on the rear wheel load in a certain assumed state. In order to balance both, each is set to a certain value and used. Therefore, while the vehicle is running in an assumed state, it provides a sufficient buffering function, but when the vehicle deviates from the assumed state, a sufficient buffering function cannot be obtained.

In particular, when a two-wheeled motor vehicle or the like suddenly decelerates, the load on the rear wheels decreases due to inertia, and the force of the springs may cause the rear wheels to jump up from the road surface in small succession.

The purpose of this invention is to make it difficult for such "rear bounce" to occur when a motorcycle or the like suddenly decelerates. This objective can be achieved by increasing the expansion damping force of the hydraulic shock absorber of the rear wheel suspension system in conjunction with braking of the motorcycle or the like.

Next, an embodiment of the present invention for a two-wheeled motor vehicle will be described with reference to the drawings.

1 is a frame of a two-wheeled motor vehicle, and 2 is a rear arm. The rear arm 2 holds a rear wheel 3 via an axle at its rear end, and is swingably attached to the frame 1 by a pivot shaft 4. Reference numeral 5 denotes a hydraulic shock absorber, which is interposed between the frame 1 and the rear arm 2 and constitutes a rear wheel suspension system. The hydraulic shock absorber 5 includes a shock absorbing spring 51 and a damper 52. The damper 52 includes a cylinder 53 filled with hydraulic oil O, a piston 54 that slides inside the cylinder 53, and one end connected to the piston 54 and the other end connected to the cylinder 5.
The piston rod 55 is provided with a piston rod 55 that protrudes outward.

The vicinity of the piston 54 will be explained using an enlarged sectional view shown in FIG. The piston 54 moves inside the cylinder 53.
The piston 54 has a throttle valve 5.
A through hole 54b having a diameter of 4a is provided, and as the hydraulic shock absorber 5 expands and contracts, flow resistance of the hydraulic oil 0 is generated.

The piston rod 55 is provided with a communication hole 55a, which communicates the two chambers partitioned by the piston 54, in parallel with the through hole 54b. This communication hole 5
A needle 55b faces inside 5a to form a variable orifice. A push rod 55c, which is slidably inserted into a through hole of the piston rod 55, is in contact with the rear end of the needle 55b.
The variable orifice formed in the communication hole 55a generates a damping force (extension damping force) during the extension operation of the hydraulic shock absorber 5, and generates only a very small damping force during the compression operation.

A tank 56 is divided into a hydraulic oil chamber and a high pressure gas chamber by a free piston 56a. This absorbs volume fluctuations caused by the piston rod 55 entering the cylinder 52.

The valve 57 is a check valve provided in each of fixed diameter orifices provided for each of the expansion and compression operations of the hydraulic shock absorber. 58 is a needle, valve 5
A variable orifice is formed in parallel with 7 to generate most of the damping force (referred to as compression damping force) during the compression operation of the hydraulic shock absorber 5.

Reference numeral 59 denotes an adjustment pulley for adjusting the expansion damping force of the hydraulic shock absorber 5. That is, the needle 55b that generates an elongation damping force is pushed rearward by the hydraulic pressure inside the cylinder 53, and its rear end is supported by a push rod 55c, and its rear end is supported by a pin 55d, which passes through a long hole in the screw member. Both ends are supported by this adjustment pulley 59. This adjustment pulley 59 is threaded onto the outer diameter screw (in this embodiment, it is a right-hand thread) of a threaded member externally fitted and fixed to the piston rod 55, so the rotational displacement of the adjustment pulley 59 corresponds to the advance and retreat of the needle 55b. Become.

6 is a brake pedal, and 61 is a pulley. The pulley 61 is configured to rotate around a brake shaft 62 integrally with the brake pedal 6.

7 is an interlocking mechanism, which includes an adjustment pulley 59 and a pulley 61.
This is linked to the following. In this embodiment, the interlocking mechanism 7 is made of an endless Bowden wire.

71 is the inner wire, 72 is the outer wire,
The outer wire 72 may be fixed at an appropriate position on the frame 1. Reference numeral 73 denotes a locking member that allows the inner wire 71 to interlock the pulleys 59 and 61 without slipping. Such interlocking mechanism 7
According to the invention, when the brake pedal 6 is depressed as shown by the arrow in FIG. 5, the pulley 61 and the adjusting pulley 59 are rotated to the right and are externally fixed to the piston rod 55. Since the thread of the screw member is a right-hand thread,
Advance the needle 55b. As a result, communication hole 5
The opening area of the orifice in 5a is reduced, and the expansion damping force of the hydraulic shock absorber 5 is increased.

Note that although the embodiments described here relate to two-wheeled motor vehicles, they can be similarly applied to three-wheeled motor vehicles.

As explained above, the present invention provides a rear wheel suspension system for a motorcycle or the like using a hydraulic shock absorber, which is configured to increase the expansion damping force of the hydraulic shock absorber in conjunction with braking of the motorcycle, etc. Therefore, even if the rear wheel load decreases when a motorcycle or the like suddenly decelerates, the force of the buffer spring is offset by the increase in damping force, making it difficult for "rear bounce" to occur.

[Brief explanation of the drawing]

Figure 1 is a side view schematically showing the motorcycle;
The figure is a sectional view of the hydraulic shock absorber, Figure 3 is a detailed sectional view of the part in Figure 2, Figure 4 is a detailed sectional view of the part in Figure 2,
FIG. 5 is an explanatory diagram of the interlocking mechanism. 1... Frame, 2... Rear arm, 3... Rear wheel, 5... Hydraulic shock absorber, 6... Brake pedal,
7... Interlocking mechanism, O... Hydraulic oil, G... High pressure nitrogen gas.

Claims (1)

[Scope of Claims] 1. A rear wheel suspension system for a motorcycle or the like using a hydraulic shock absorber, which is configured to increase the expansion damping force of the hydraulic shock absorber in conjunction with braking of the motorcycle, etc. Rear wheel suspension system for motorcycles, etc.