JPS623557Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a hydraulic shock absorber for a vehicle.

Hydraulic shock absorbers used in conventional motorcycles and the like generally have an air chamber and an oil reservoir chamber inside, and are designed to compensate for the intrusion volume of the piston rod by contraction of the air chamber. In this case, the damping force during compression side and expansion side operation is generated according to the piston speed, and as the speed increases, a higher damping force can be obtained, but the damping force depends on the piston position, that is, the stroke position. It never changed.

For example, the following problems arose. In other words, in hydraulic shock absorbers for street vehicles, the damping force is set relatively low because the road surface has small undulations.
Improves responsiveness. However, when cornering, the vehicle body sinks, and if the damping force is small in this sunken state, handling becomes extremely poor. Therefore, it is required that the damping force of the front fork and rear fork be reduced near the IG, but increased during cornering to improve the ground contact of the vehicle body.

Hydraulic shock absorbers for off-road vehicles have a large stroke and have large undulations on the road surface, so 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 near the maximum compression, so during the extension operation, it picks up bumps on the road surface and can cause the tire to bottom out.

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

Therefore, in order to solve these problems, the spring load of the suspension was detected and the damping force was variably adjusted according to the spring load, as disclosed in Utility Application No. 55-92466. something is proposed.

As shown in Fig. 1, this hydraulic shock absorber has an inner tube 1 slidably inserted into an outer tube (not shown), and a relief valve 9 arranged in a passage through which hydraulic oil flows out as the inner tube 1 contracts. In order to increase the spring load of the internal spring 11 of the relief valve 9 in accordance with the amount of compression of the suspension spring 6, a spring receiving plate 4 of the relief valve 9 is provided between the suspension spring 6 and the detection spring 7 facing thereto. I try to keep it. In addition, 2 is a cylinder, 3 is a piston part, 8
is a check valve that opens without resistance during extension action,
5 is a valve holder, and 10 is a throttle passage.

However, in this hydraulic shock absorber, the valve holder 5 housing the relief valve 9 and check valve 8, the internal spring 11 of the relief valve, the detection spring 9, and the spring receiving plate 4 are each separate pieces, so assembly is difficult. On the other hand, since the flow path is located inside the spring, a sufficient flow path area cannot be ensured, resulting in a problem that the damping effect is impaired.

This idea was made in order to solve the above problems, and it is easy to assemble the damping force adjustment mechanism, and it is possible to obtain an effective damping effect by variably adjusting the damping force in response to the spring load. The purpose of this project is to provide a hydraulic shock absorber.

Hereinafter, embodiments of this invention will be described based on the drawings.

First, the configuration will be explained with reference to FIG. 2. 1 is an inner tube, 2 is a cylinder connected at its base end to an outer tube (not shown), and 3 is a piston part. Slide on the inner circumference of the

Next, at an upper position of the piston part 3, a valve holder 12 having a side hole 12a in the upper circumferential surface of the cylinder body is placed between a detection spring 7 and a variable spring receiver 9 (described later).
The sheet part 13 and the guide part 14 are fitted inside the sheet part 13 and the guide part 14 .

A passage 15 and a central hole 16 are formed in the seat part 13, and a check valve 8 is disposed on the front side of the passage 15 and is biased by a check spring 17, which opens without resistance when the valve is extended. A bolt 18 is slidably inserted upward into the central hole 16.

The lower part of the bolt 18 is defined by a large diameter part 18a that slides into the central hole 16 of the seat part and a small diameter part 18b above the large diameter part 18a. A variable spring receiver 19 is slidably inserted into the small diameter portion 18b above, and a relief valve 9 is fitted below, and an internal spring 1 is inserted between the two.
The variable spring receiver 19 is locked by a nut 20 screwed onto the bolt 18, and the relief valve 9 is locked by a stepped portion 18a' of the large diameter portion 18a. The relief valve 9 is composed of a plate valve part 21 and a spring receiving part 22, which are connected to the bolt 1.
8, the check valve, the variable spring receiver 19, the internal spring 11, and the detection spring 7 are pre-assembled into a unit.

On the other hand, the variable spring receiver 19 is positioned according to the balance between the suspension spring 6 biased toward the compression side and the detection spring 7 biased toward the expansion side.
At the maximum extension shown in the figure, a clearance of δ is set between the relief valve 9 and the check valve 8.

Further, even if the detection spring 7 is brought into close contact with the inner spring 11 during the compression operation, the internal spring 11 can be further bent. Note that A is the oil sump chamber and B is the inner tube 1.
This is an oil chamber defined between the cylinder 2 and the cylinder 2.

Next, the effect will be explained.

Clearance δ between relief valve 9 and check valve 8
When driving near IG where the pressure is large, the relief valve 9 hardly functions, and therefore the generated damping force is small.
Provides a soft ride.

On the other hand, when the spring load increases, such as when loading a vehicle, the inner tube 1 relatively descends, and the clearance δ decreases. In other words, when a load that exceeds the balance with the detection spring 7 is applied to the suspension spring 6, the detection spring 7 begins to contract and the clearance δ becomes smaller. This provides resistance to the hydraulic oil flowing from the oil chamber B to the oil reservoir chamber A, and provides an appropriate damping force (variable orifice characteristics). Clearance δ=
Even if it becomes 0, the internal spring 11 is further bent, so the set load of the relief valve 9 is further increased. Therefore, for example, when the shock absorber is about to bottom out, a very high damping force is generated, and this Effectively prevent.

The work of assembling the damping force adjustment mechanism C of this hydraulic shock absorber is done in advance by attaching the bolt 18 to the valve holder 12.
The relief valve 9, the variable spring receiver 19, the internal spring 11, and the detection spring 7 are assembled to the bolt 18, and the set is inserted into the cylinder 2 via the guide part 14 of the valve holder 12. It is extremely easy to just insert and fit. In addition, since the oil flow path area can be set sufficiently large in the valve holder 12 toward the inner wall of the inner tube 1 without passing through the inside of the springs 7, 11, or 6, the damping characteristics are not affected by the expansion and contraction of the springs. There is an effect that there is no.

FIG. 3 shows another embodiment of the present invention, in which the check valve 8 is separated from the relief valve 9 and arranged on the rear side of the valve holder 12, and a special suction port 12b to the oil chamber B is provided. It is something that Note that 23 is a stopper cylinder of the check valve 8.

As explained above, in this invention, the damping force adjustment mechanism is in a cassette state in advance, and a sufficient flow area is provided without passing through the inside of the spring, making assembly work extremely easy and effective. This has the effect of providing a damping effect.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view showing the main part configuration of a conventional hydraulic shock absorber, Fig. 2 is a longitudinal sectional view showing the main part structure of a hydraulic shock absorber according to this invention, and Fig. 3 is another embodiment of the present invention. FIG. 1...Inner tube, 2...Cylinder, 6
... Suspension spring, 7 ... Detection spring, 8 ... Check valve, 9 ... Relief valve, 11 ... Internal spring, 12
... Valve holder, 13 ... Seat part, 18 ... Bolt, 19 ... Spring receiver, 21 ... Plate valve part of the relief valve, 22 ... Spring receiver of the relief valve.

Claims (1)

[Scope of utility model registration request] In a hydraulic shock absorber in which an inner tube is slidably inserted into an outer tube and a cylinder is interposed within the inner tube, a passage opening in the cylinder through which hydraulic oil flows out as the inner tube contracts. A suction check valve at the time of extension and a relief valve at the time of compression are mounted and provided by a valve holder, and the relief valve is fitted onto a shaft body slidably supported on a seat portion in the valve holder. The relief valve is constructed of a plate valve with a fixed plate valve and an internal spring interposed between the plate valve and a variable spring receiver. and a detection spring opposed thereto are made to act oppositely to the variable spring receiver, and the relief valve, the variable spring receiver, and the detection spring are slidably assembled and supported in advance on the same shaft body. A hydraulic shock absorber characterized by: