JPH02169314A - vehicle shock absorber - Google Patents

Abstract

PURPOSE:To perform the adjustment of damping force attending on a stroke change so simply and accurately by moving a push rod up and down via a cam face with the rocking motion of a swing arm, while adjusting the damping force of a shock absorbing part with this vertical motion. CONSTITUTION:During vehicle running, when a cushion arm 6 is rocked upward with each rocking motion of rear wheels, an inner cylinder 16 is rocked upward with a piston 19. Accordingly, a hydraulic fluid in a chamber S2 flows into an orifice 24b from a hole part 25a, pressing a check valve 26 downward and, after flowing into a chamber S3, it flows into a hollow chamber S4 by way of an oil passage 33. Therefore there is produced damping force in a compression stroke by an interaction between the orifice 24b and the check valve 26. At this time, a push rod 24 is slid upward by a cam face formed on top of the cushion arm 6 via a ball 29. With this constitution, a coil spring 28 is compressed, and thereby force for energizing the check valve 26 is strengthened and thus the damping force is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a shock absorber for a vehicle that changes damping force as the stroke of the shock absorber changes.

(Prior Art) Conventionally, some vehicles such as motorcycles are provided with an M street device to damp vertical vibrations of the vehicle body caused by unevenness of the road surface.

(Problem to be solved by the invention) However, since this Mi town device is configured to always generate a constant damping force regardless of stroke changes, the damping force on the compression side is lowered with emphasis on riding comfort. If the damping force is set higher on the compression side to prevent bottoming, the ride quality will be worse. There is a problem with putting it away.

As a prior art to solve this problem, Japanese Patent Publication No. 59-29467
The &l shock device disclosed in No. This shock absorber is a swing arm and 1! A link mechanism is interposed between the swing arm and the street equipment, and the amount of swinging displacement of the swing arm is increased depending on the position and transmitted to the shock absorber. However, if a structure is adopted in which transmission is performed via such a link, rattling may occur, and the number of parts and weight may increase.

The present invention was made in view of the above problems, and its purpose is to be able to change the damping force as the stroke changes without adopting a complicated link structure, and to set the damping force with emphasis on riding comfort. To provide a buffer that does not cause bottoming out, etc.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an upper part of a hydraulic shock absorber in which a damping force is generated by passing hydraulic oil in a cylinder through an orifice formed in the cylinder. In a shock absorber for a vehicle, which is attached to the body frame of the vehicle and the lower part of the hydraulic shock absorber is attached to a swing arm extending swingably from the body frame or a cushion arm interlocking with the swing arm, one end is inserted into the cylinder. A push rod is slidably inserted into the cylinder and its other end projects outside the cylinder, and damping force adjusting means is provided below the orifice in the cylinder to change the damping force of the shock absorber by vertical movement of the push rod. The present invention is characterized in that a cam surface is formed on the swing arm or the cushion arm to move the push rod up and down by the swinging of the swing arm.

(Function) The damping force of the shock absorber can be changed in accordance with stroke changes, and even if the damping force on the compression side is set with emphasis on ride comfort, it is possible to prevent bottoming out while driving, resulting in a comfortable ride. It is possible to ensure comfort and improve driving performance.

(Embodiment) A preferred embodiment of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a side view of the shock absorber according to the present invention, and FIG.
1 is a body frame of a motorcycle, and the base end of a swing arm 3 extending toward the rear of the vehicle body is attached to a bracket 2 formed on the frame 1 in the vertical direction via a shaft portion 4. The swing arm 3 is attached to the swing arm, and the rear wheel 5 is pivotally supported at the tip of the swing arm 3. A cushion arm 6 is attached to a portion of the vehicle body frame 1 below the swing arm 3 via a shaft portion 7 so as to be swingable in the vertical direction, and a shaft portion 8 provided at an intermediate portion of the cushion arm 6 is attached to the swing arm. It is rotatably supported by a bracket 9 formed below 3.

When the swing arm 3 swings in the vertical direction, the swing arm 3 also swings in the vertical direction in conjunction with this.

Reference numeral 10 denotes a shock absorber, the upper end of which is provided at the upper end of an upper bracket 11 which also serves as a spring holder is pivotally supported by a bracket 12 formed on the vehicle body frame 1, and the lower end thereof is supported by a support member 13.
said cushion arm 6 via bolt 14.14
Attach to the tip of the

The details of the shock absorber 10 are as shown in FIG. 3, and hydraulic oil is sealed in the cylinder 20 of the shock absorber 10.
consists of an outer cylinder 15 and an inner cylinder 16 fixedly installed inside the outer cylinder 15, and an intermediate chamber S4 is formed between the outer cylinder 15 and the inner cylinder 16.

Further, a bottom member 17 is fixed to the lower part of the outer cylinder 15, and the substrate 13a of the support member 13 described above is fitted to the outer periphery of the cylindrical portion 17a provided at the center of the bottom member 17.
The legs 13b, 13b hanging down from both ends of a are attached to the cushion arm 6 with bolts 14°14 as described above. Further, a spring receiver 21 is provided on the outer periphery of the approximately intermediate portion of the outer cylinder 15,
A coil spring 22 is stretched between the spring receiver 21 and the upper bracket 11. A partition wall 18 is provided at the lower end of the inner cylinder 16, and a piston 19 is provided inside the inner cylinder 16 to connect the cylinder 20.
There are chambers 51, 52 inside. S3 is defined, and the partition wall 18 has an oil passage 3.
3... are provided to communicate between the intermediate chamber S4 and the chamber S1. The upper end of the rod 19a of the piston 19 is fixed to the upper bracket 11, and the cylinder 20 can swing freely relative to the piston 19. When the swing arm 3 swings up and down, the cylinder 20 (directly The inner cylinder 16) slides vertically relative to the piston 19.

A pin 23 is screwed into the center of the partition wall 18, and a shaft portion 23a of the pin 23 passes through the cylindrical portion 17a of the bottom member 17.
A push rod 24 is provided between the cylindrical portion 17a and the cylindrical portion 17a so as to be slidable in the vertical direction along the shaft portion 23a. On the other hand, a plurality of orifices 24a..., 24b... are formed in the partition wall 18, with an outer orifice 24a... and an inner orifice 24a...
4b...), and a check valve 25 is provided on the top surface of the partition wall 18.
A disc spring 36 is provided between the check valve 25 and the head 23b of the pin 23, and the disc spring 36 closes the check valve 25.
is always urged toward the partition wall 18. At this time, the upper openings of the outer orifices 24a... are closed by the check valves 25, but the inner orifices 24b...
The upper opening is always in communication with 32 via 5a. or,
A check valve 26 is provided on the lower surface of the partition wall 18 to close the lower opening of the inner orifice 24b, and the check valve 26 is always kept in the direction of the partition wall 18 by a coil spring 28 stretched between it and a spring support 27 provided at the upper part of the bush rod 24. is urged to.

By the way, the push rod 24 protrudes from the bottom member 17 by a predetermined length, and as shown in FIG. are in contact. When the cushion arm 6 swings upward, the tip of the push rod 24 slides along the cam surface 30, thereby causing the push rod 24 to slide upward (in the direction). Along with this, the spring receiver 27 also moves upward, and the coil spring 2
8, and the force for energizing the check valve is strengthened.

In the drawings, 31 is a seal member provided between the outer cylinder 15 and the piston rod 19a, and 32 is a seal member provided between the inner cylinder 16 and the piston 19.

Next, the operation of the present invention will be described.

First, when the rear wheel 5 moves upward due to unevenness on the road surface while driving, and the swing arm 3 swings upward, the cushion arm 6 also swings upward in conjunction with this, which causes the inner cylinder 16 to move against the piston 10. The hydraulic oil in the chamber Sz flows from the hole 25a into the orifice 24b, pushes down the check valve 26, flows into the chamber S3, and further passes through the oil passage 33 to the intermediate chamber S4. Flow into. At this time, as the hydraulic oil flows through the orifice 24b, the check valve 26
By pushing down, a damping force is generated during the compression stroke. On the other hand, at this time, the tip of the push rod 24 is connected to the cam surface 3.
0, the push rod 24 moves upward (A
direction), and as mentioned above, the spring receiver 27 also moves upward,
The coil spring 28 is compressed and the force urging the check valve 26 is increased. That is, in the compression stroke, as the inner cylinder 16 moves upward, the damping force increases.

Since the present invention is configured as described above, even if the damping force is set to be a little weak with emphasis on ride comfort while driving, the damping force will increase as the cylinder moves upward during the compression stroke, and the damping force will increase as the cylinder moves upward during the compression stroke. Bottoming out and the like can be prevented, and driving performance can be improved while ensuring a comfortable ride.

In this embodiment, a cam surface is provided on the cushion arm 6 that is linked to the swing arm 3, and the push rod 24 is brought into contact with the cam surface. The tip of the push rod 24 may be brought into contact with the front end of the push rod 24, thereby reducing the number of parts.

(Effects of the Invention) As described above, according to the present invention, the damping force of the M balance can be changed according to stroke changes without using a complicated link mechanism, and the damping force can be set with emphasis on riding comfort. It is possible to prevent the vehicle from bottoming out while driving, thereby ensuring a comfortable ride and improving driving performance.

[Brief explanation of the drawing]

Figure 1 relates to the present invention! FIG. 2 is a partially enlarged view of FIG. 1, and FIG. 3 is a front sectional view of the shock absorber. In addition, in the drawing, 1 is the vehicle body frame, 3 is the swing arm, and 6
is a cushion arm, 10 is a shock absorber, 20 is a cylinder,
24 is a push rod, 24a and 24b are orifices,
26 is a check valve, 27 is a spring holder, 28 is a coil spring,
30 is a cam surface.

Claims (1)

[Scope of Claims] The upper part of a hydraulic shock absorber is configured to generate damping force by passing the hydraulic oil in the cylinder through an orifice formed in the cylinder, and the lower part of the hydraulic shock absorber is attached to the body frame of a vehicle. In a vehicle shock absorber, which is attached to a swing arm swingably extending from the vehicle body frame or a cushion arm interlocking with the swing arm, there is a pusher whose one end is inserted into the cylinder and the other end projects outside the cylinder. The rod is slidably provided, and a damping force adjustment means is provided near the orifice in the cylinder to change the damping force of the shock absorber by vertical movement of the push rod, and the swing arm or the cushion arm is provided with damping force adjusting means for changing the damping force of the shock absorber by vertical movement of the push rod, A shock absorbing device for a vehicle, characterized in that a cam surface is formed to move the push rod up and down.