JPS6124743Y2 - - Google Patents

Description

[Detailed explanation of the idea] (Industrial application field) This invention relates to a hydraulic shock absorber for two-wheeled vehicles.

Hydraulic shock absorbers used in conventional motorcycles generally have an air chamber and an oil reservoir chamber inside.
The intrusion volume of the piston rod is compensated for by the contraction of the air chamber. In this case, the damping force during the compression side and expansion side operation is generated according to the piston speed, and the higher the speed, the higher the damping force can be obtained, but normally it depends on the piston position, that is, the stroke position. It does not change the damping force.

As a result, the following problems arose.

For example, in hydraulic shock absorbers for street vehicles, the damping force is set relatively low because the road surface has small undulations to improve responsiveness.However, when cornering, the vehicle body sinks, so this sinking The required damping force is large when the vehicle is in a state of suspension, so while the damping force of the front fork and rear fork should be small near IG, it is also required to increase it during cornering to improve the ground contact of the vehicle body.

Hydraulic shock absorbers for off-road vehicles have a large stroke amount, and if the road surface has large undulations, the damping force during normal driving is also set to be relatively large.
However, this damping force also provides resistance to the extension operation from the vicinity of maximum compression, so during the extension operation, the vehicle may pick up bumps on the road surface and bottom out.

Furthermore, in the case of a loaded vehicle, it is necessary to adjust the damping force between empty and loaded vehicles.

(Problems to be solved by the invention) Therefore, in order to solve these problems, as disclosed in Utility Model Application No. 52-146461, the flow path area for damping force generation was It has been proposed to change the value sequentially according to the

However, such a means of sequentially changing the flow path area requires a large amount of man-hours to process, leading to high costs.In addition, since the damping force characteristics in both the expansion and contraction operating regions change simultaneously, It was not possible to independently change the damping characteristics and the compression side operation with the desired damping characteristics. Therefore, even if suitable damping force characteristics are obtained in the compression side operation, there is a problem in that the damping force characteristics are poor in the rebound side operation.

In addition, as disclosed in Utility Model Application No. 17481/1981, when the piston descends to a certain position, the resistance of the piston-side valve is changed by a spring placed in the cylinder in advance, and the damping force characteristics of the piston are changed. It has also been proposed to change the temperature in the middle of the operating range.

However, since the positioning for changing the damping force characteristics is determined in advance by the length of the spring, there was a problem in that the position could not be adjusted.

(Means for solving the problem) This idea was made in order to solve the problems of the conventional technology.It detects the spring load of the suspension spring and changes the damping force in accordance with the spring load. The purpose is to provide an adjustable hydraulic shock absorber.

Therefore, the present invention provides a hydraulic shock absorber in which an inner tube is slidably inserted into an outer tube, a cylinder is provided in sliding contact with the inside of the inner tube, and a suspension spring is interposed between the cylinder and the inner tube. A pressure side port is formed in the cylinder to communicate the lower oil chamber formed between the cylinder and the oil reservoir chamber above the inner tube via the inside of the cylinder, and the base end of the cylinder is designed to expand or contract the area of this port. is slidably inserted into a cylindrical member fixed to the outer tube, and a detection spring is interposed at the end of the cylinder opposite the suspension spring.

(Example) Hereinafter, an example of this invention will be described based on the drawings.

FIG. 1 shows an embodiment of this invention.

First, to explain the configuration, 1 is an outer tube, 2 is an inner tube, 3 is a cylinder, and 4 is an expanded diameter part, and the cylinder 3 slides on the inner circumference of the inner tube 2 via the expanded diameter part 4. A check valve 6 is disposed at the piston portion 2A at the tip of the inner tube 2. Further, a detection piston 8 having a pressure side port 9 on the circumferential surface is integrally connected to the base end of the cylinder 3, and this piston 8 is connected to a detection cylinder 10 whose base is fixed to the outer tube 1 via a detection spring 11. Fitted with free sliding.

The inner upper end of the inner tube 2 that slides on the inner periphery of the outer tube 1 and the expanded diameter portion 4 of the cylinder 3
A suspension spring is interposed between the inner tube 2 and the upper end to urge the inner tube 2 toward the extension side.

Further, an oil reservoir chamber 7 is provided inside the inner tube 2 near the expanded diameter portion 4, and the oil reservoir chamber 7 passes through the inside of the cylinder 3 and is connected to the inner tube 2 through a pressure side port 9 provided on the detection piston 8. It communicates with a lower oil chamber 14 formed at the lower part. The upper oil chamber 12, which is formed between the check valve 6 which opens on the pressure side and the expanded diameter portion 4 of the cylinder 3 and between the inner circumference of the inner tube 2 and the outer circumference of the cylinder 3, is connected to the lower oil chamber through the check valve 6. It communicates with room 14.

In a stationary state, the compression side port 9 is open due to the balance of the biasing forces of the suspension spring 5 and the detection spring 11.
This will be explained using the spring characteristic diagram in FIG. 2.
If the vertical axis represents the spring load A and the horizontal axis represents the stroke B of the outer tube 1, the initial set load of the suspension spring 5 is set smaller than the initial set load of the detection spring 11, but after the suspension spring 5 is loaded and reaches position P where it balances with the initial set load of the detection spring 11, the detection spring 11 also begins to contract, and the combined spring force E of both springs 5, 11 is obtained during the contraction stroke C. In this case, if the initial set load of the suspension spring 5 is changed by a known means such as a cam, it will sooner reach position Q where it balances with the initial set load of the detection spring 11, and the lock stroke D will change, but this has the following advantages.

That is, the initial setting load of the spring is adjusted in order to bring the IG position closer to the appropriate sinking position depending on the magnitude of the live load. Therefore, when the load changes, it is preferable that the lock stroke D at maximum compression also changes accordingly.

In this embodiment, by applying an initial setting load to the detection spring 11 and adjusting the initial setting load of the suspension spring 5 within a range below this load, the lock stroke D at the maximum compression is automatically adjusted according to changes in the live load. It can be adjusted to

However, in this embodiment, it is also possible to make the initial setting loads of the suspension spring 5 and the detection spring 11 the same.

Next, the effect will be explained.

When a large load exceeding the initial setting load of the detection spring 11 is applied to the suspension spring 5, the detection spring 11
Cylinder 3 moves downward while compressing . Therefore, the diameter of the pressure side port 9 is narrowed by the detection cylinder 10, so that the damping force can be increased.

In this case, part of the oil in the lower oil chamber 14 is introduced into the upper oil chamber 12 via the check valve 6, and the rest is introduced into the oil reservoir chamber 7 via the pressure side port 9.

Therefore, when the pressure side port 9 is throttled in this way, the pressure of the hydraulic oil in the lower oil chamber 14 increases in proportion to the compression speed of the inner tube 2.
For example, if the vehicle runs over a large bump on the road,
When the inner tube 2 compresses rapidly due to a sudden stop, etc., the damping force increases in proportion to the amount of compression, which suppresses the sudden sinking of the inner tube 2 and improves maneuverability. .

(Effects of the invention) As explained above, this invention changes the damping force by displacing the cylinder according to the spring load of the suspension, so the damping force setting for displacement can be easily changed by the characteristics of the load detection spring. This has the effect that the compression side damping force can be easily adjusted.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of the main part of an embodiment of this invention.
FIG. 2 is an explanatory diagram showing the characteristics of the spring in the embodiment of FIG. 1. DESCRIPTION OF SYMBOLS 1... Outer tube, 2... Inner tube, 3... Cylinder, 4... Expanded diameter section, 5... Suspension spring, 6... Check valve, 7... Oil reservoir chamber, 8...
...detection piston, 9 ... pressure side port, 10 ... detection cylinder, 11 ... detection spring, 12 ... upper oil chamber, 14 ... lower oil chamber.

Claims (1)

[Scope of utility model registration request] In a double-tube hydraulic shock absorber, an inner tube is slidably inserted into an outer tube, a cylinder is provided in sliding contact with the inside of the inner tube, and a suspension spring is interposed between the cylinder and the inner tube. A pressure side port is formed in the lower part of the cylinder that communicates the lower oil chamber formed between the cylinder and below the piston of the inner tube with the oil reservoir chamber above the inner tube via the inside of the cylinder, and the area of this port is A hydraulic shock absorber characterized in that the base end of the cylinder is slidably inserted into a cylindrical member fixed to an outer tube in order to expand and contract the cylinder, and a detection spring is interposed at the end of the cylinder in opposition to a suspension spring. .