JPH0353079Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a valve structure for generating damping force in a shock absorber used in automobiles and the like.

(Prior Art) As shown in FIG. 4, a hydraulic shock absorber used in automobiles and motorcycles has a piston rod 52 inserted into a cylinder 51 from above, and a tip of the piston rod 52 inserted into the cylinder 51. A piston 53 is attached that slides on the circumferential surface. Then, the piston rod 52 above this piston 53
A valve collar 54 and a stopper 55 are fitted on the outer periphery, a valve case 56 is provided between the stopper 55 and the piston 53, a valve 58, a valve retainer 59 and a spring 60 are sequentially assembled into the valve case 56 from below. The plate valve 58 is pressed against the valve seat portion 53b formed on the upper part of the piston 53 with a restoring force of 60 degrees. Furthermore, a buffle 63 is fitted between the lower end of the piston 53 and a nut 62 for fixing and holding the piston 53 to the piston rod 52.

In this hydraulic shock absorber, the stroke speed (upward movement) of the piston 53 during the extension stroke
When the pressure in the upper oil chamber _S3 is extremely slow, the plate valve 58 is not bent by the pressure in the upper oil chamber S3, the oil hole 59a in the valve retainer 59 remains blocked by the plate valve 58, and the hydraulic oil in the upper oil chamber _S3 is It flows into the lower oil chamber _S4 through a slit (not shown) in the plate valve 58, and when the stroke speed of the piston 53 increases,
The pressure inside the oil chamber _S3 increases, and the plate valve 58 is bent by the hydraulic pressure, causing the valve retainer 59 and the plate valve 5 to flex.
A flow path is opened between 8 and a damping force is generated in this flow path.

In this case, by providing a buffer 63 to narrow the flow path 53a formed in the piston 53 and restricting the flow of hydraulic oil, suction performance is improved, and when the flow rate of hydraulic oil is high, the hydraulic oil is 63 and disperse it to prevent abnormal noises from occurring.

(Problems to be solved by the invention) In the valve structure of the hydraulic shock absorber described above,
Since the buttful is attached to the lower side of the piston, when the hydraulic oil flows from the lower oil chamber _S4 to the upper oil chamber _S3 during the compression stroke, the flow of hydraulic oil is restricted by the buttful 63, which prevents compression. The damping force in the stroke becomes too large.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a check valve that partially blocks the flow path of the piston between the plate valve and the valve seat. It was fitted so that it could slide freely.

(Function) In the extension stroke, the check valve moves to the valve seat side and restricts the flow path, which improves the suction of oil from the reservoir chamber and prevents the generation of abnormal noises.In the compression stroke, the check valve moves to the plate valve. Since it moves to the side and opens the flow path, the flow of hydraulic oil is not restricted and the damping force does not become too large.

(Example) Examples of the present invention will be described below with reference to the accompanying drawings.

1 and 2 are cross-sectional views showing the operating states of a hydraulic shock absorber having a valve structure according to the present invention during an extension stroke and a compression stroke.

The hydraulic shock absorber has a piston rod 2 inside the cylinder 1.
is inserted from above, and a piston 3 is attached to the tip of the piston rod 2, which slides on the inner peripheral surface of the cylinder 1. The piston 3 moves the inside of the cylinder 1 between an upper oil chamber _S1 and a lower oil chamber S. It is divided into ₂ . Furthermore, a valve mechanism 5 for generating damping force is provided at the upper part of the piston 3.

This valve mechanism 5 includes a valve collar 6 and a stopper 7 fitted on the outer periphery of the piston rod 2 above the piston 3, a valve case 8 provided between the stopper 7 and the piston 3, and a valve case 8 inserted into the valve case 8 from below. Sequential plate valve 10, valve retainer 1
1 and spring 12, and spring 12
The restoring force presses the plate valve 10 against the valve seat 3b formed on the upper part of the piston 3.

Furthermore, between the plate valve 10 and the piston 3,
A check valve 15 that partially blocks the flow path 3a of the piston 3 is slidably fitted into the valve collar 6.

The operation of the valve structure constructed as described above will be explained.

First, during the extension stroke, when the piston 3 moves upward and the pressure in the upper oil chamber _S1 increases,
The hydraulic oil in the upper oil chamber _S1 flows into the valve case 8 and passes through the oil hole 11a of the valve retainer 11 while pushing down the valve retainer 11, and then the plate valve 10
is bent to open the oil hole 11a of the valve retainer 11, and the check valve 15 is further pushed down to block a part of the flow path 3a of the piston 3, so that the oil flows as shown by the arrow in FIG. Flow into ₂ . Therefore, when the hydraulic oil flows from the upper oil chamber _S1 to the lower oil chamber _S2 , the flow of the hydraulic oil is restricted by the flow path 3a of the piston 3, so that no abnormal noise or the like is generated.

In addition, in the compression stroke, when the piston 3 moves downward and the pressure in the lower oil chamber _S2 increases, the hydraulic oil in the lower oil chamber _S1 passes through the flow path 3a of the piston 3 and checks the check valve 15. is pushed up to open the flow path 3a of the piston 3, and the plate valve 10 is further pushed up to close the oil hole 11a of the valve retainer 11, and the check valve 1 is pushed up against the spring 12.
5. Push up the plate valve 10 and valve retainer 11 together to open the gap between the valve seat 3b and the plate valve 10, and flow as shown by the arrow in FIG. ₂ into the upper oil chamber S1. Therefore, during the compression stroke, the check valve 15 does not block part of the flow path 3a of the piston 3, so the hydraulic oil flows smoothly in the flow path 3a, and the damping force does not become too large.

3A and 3B are views showing other embodiments, in which a coil spring 20 is installed between the valve retainer 11 and the check valve 15.
or a plate spring 21 is interposed between the plate valve 10 and the check valve 15 to bias the check valve 15 in the closing direction.

(Effects of the invention) As explained above, according to the invention, a check valve is provided between the plate valve and the valve seat, and this check valve is slidably fitted into the valve collar, so that the extension stroke Then, the check valve moves to the flow path side of the piston and blocks part of the flow path to restrict the flow of hydraulic oil, improve the suction of oil from the reservoir chamber, and prevent the occurrence of abnormal noises. Further, in the compression stroke, the check valve moves toward the plate valve side to open the flow path of the piston, so that a predetermined damping force can be obtained without making the damping force too large due to the check valve.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing the state of a hydraulic shock absorber equipped with the valve structure according to the present invention in the extension stroke;
The figure is a cross-sectional view showing the state of the buffer during the compression stroke.
3A and 3B are views showing another embodiment, and FIG. 4 is a sectional view showing a conventional valve structure. In the drawings, 1 is a cylinder, 2 is a piston rod, 3 is a piston, 3b is a valve seat, 6 is a valve collar, 10 is a plate valve, 11 is a valve retainer,
15 is a check valve.

Claims (1)

[Scope of utility model registration request] In a hydraulic shock absorber that generates damping force by circulating hydraulic oil from a high-pressure oil chamber in a cylinder to a low-pressure oil chamber via a valve provided on a piston, the valve is slidably fitted in a valve collar. It consists of a valve retainer, a plate valve interposed between the valve retainer and the valve seat, and a check valve that partially blocks the flow path of the piston, and the check valve is slidably fitted into the valve collar. A valve structure for generating damping force of a hydraulic shock absorber, which is characterized by: