JPH0727164A - Valve structure of shock absorber - Google Patents

Abstract

PURPOSE:To facilitate regulation of the damping force of a shock absorber at the very low speed area and the low speed area of a piston speed. CONSTITUTION:A piston 4 is fixed to the tip of a piston rod 3 by means of a nut 5 togetherwith a stopper 9, a retainer 6, a disc spring 7, a non-return valve 8, leaf valves 21 and 22, and valve seats 10 and 11, and communicating passages 12 and 13 through which upper and lower chambers 14 and 15 are intercommunicated are provided. The leaf valve 22 for a middle and high area the inner peripheral side of which is nipped between the valve seat 11 and the seat surface 24 on the inner peripheral side of the piston 4 and the leaf valve 21 for a very low speed and a low speed area freely supported between the leaf valve 22 and the piston 4 are arranged on the lower chamber 15 side of the communicating passage 13. A shoulder part 25 is arranged on the seat surface 24 on the inner peripheral side of the piston 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorber used for a suspension of an automobile or the like, and more particularly to a valve structure thereof.

[0002]

2. Description of the Related Art In a shock absorber having a variable damping force, a leaf valve is provided on a seat surface of a piston,
A device that generates a damping force by bending the leaf valve has been conventionally devised. As such a technique, there is one disclosed in Japanese Utility Model Laid-Open No. 3-75334.
In this technique, the piston of the shock absorber is provided with two types of passages that connect the upper chamber and the lower chamber of the piston, and one of the passages is urged by a spring on the seat surface of the piston on the piston upper side. A non-return valve is attached. A leaf valve mechanism is provided on the lower side of the piston in the other passage.
This leaf valve mechanism includes a leaf valve for low speed range and a leaf valve for medium and high speed range. The leaf valve for the low speed range has an upper portion on the outer peripheral side abutting on the seat surface of the piston, an upper portion on the inner peripheral side separated from the seat surface of the piston, and a lower portion on the inner peripheral side abuts on the canzer. In addition, a leaf valve for medium- and high-speed regions, which has the same diameter as the leaf valve for low-speed regions, is clamped and fixed on the inner peripheral side by the canzer, and is arranged apart from the leaf valve for low-speed regions by the thickness of the canzer. . Further, a float valve for adjusting the amount of bending of the leaf valve for the low speed range is arranged between the leaf valve for the low speed range and the leaf valve for the medium and high speed ranges.

According to this prior art, during the expansion process of the shock absorber, the leaf valve is bent by the fluid passing through the passage. At that time, when the speed of the piston is low, the amount of fluid flowing into the passage is small, and the deflection of the leaf valve is small. That is, the leaf valve for the low speed region bends until its outer peripheral portion comes into contact with the float valve. Further, when the piston speed is high, the amount of fluid flowing into the passage is large, and the leaf valve is largely bent. At this time, the outer peripheral portion of the low speed region leaf valve completely contacts the float valve, and is further bent together with the float valve and the medium and high speed region leaf valve.

[0004]

However, in the valve structure having the above-mentioned structure, the damping force changes only in two stages, that is, the low speed region and the medium and high speed region of the piston speed. Therefore, there is a problem that it is difficult to adjust the damping force of the shock absorber in the low speed region of the piston speed, particularly in the low speed region.

The present invention has been made in view of the above-mentioned problems. By making the deflection of the leaf valve for the low speed range two or more steps, the change of the damping force of the absorber is three or more steps, and the piston speed changes. It is an object of the present invention to easily adjust the damping force of the shock absorber in a very low speed range.

[0006]

A shock absorber valve structure according to the present invention is a piston for partitioning a cylinder into two chambers, a communication passage provided in the piston for communicating the two chambers, and the piston. A valve structure of a shock absorber having a leaf valve provided in the first leaf valve, the leaf valve being freely supported between the first leaf valve having one end fixed and the first leaf valve and the piston. And a second leaf valve, one end side of which projects radially from the free end of the first leaf valve and which abuts the seat surface of the piston at the projecting portion, and the piston is the second leaf valve. Or a cylinder for stopping the amount of movement of the second leaf valve on the other end side when the leaf valve flexes. A valve structure of a shock absorber, comprising: a piston that divides the chamber into two chambers; a communication passage that is provided in the piston and that communicates the two chambers; and a leaf valve that is provided in the piston. Is freely supported between a first leaf valve having one end fixed and the first leaf valve and a piston, and one end side thereof projects radially from a free end portion of the first leaf valve. And a second leaf valve that is in contact with the seat surface of the piston at the protruding portion, and the other end side of the second leaf valve is located between the piston and the second leaf valve. It is characterized in that a biasing means for biasing the leaf valve side is provided.

[0007]

According to the former configuration, when the piston of the shock absorber moves and the fluid flows into the communication passage, the leaf valve bends. The bending method is as follows. When the piston speed is very low, the amount of fluid flowing into the communication passage is very small. That is, the second leaf valve only flexes slightly. At that time, since the end portion of the second leaf valve is bent without being restricted by the stopper portion, the change in the opening area of the communication passage with respect to the piston speed becomes large.
Therefore, the shock absorber generates a damping force with a small change in damping force with respect to the piston speed, that is, a gentle rising force.

If the speed of the piston becomes higher than in the above case, the deflection of the second leaf valve also becomes larger,
While one end side of the leaf valve of No. 1 is in contact with the free end portion of the first leaf valve, the other end is regulated by the stopper portion,
The second leaf valve flexes. Therefore, the change in the opening area with respect to the piston speed is small, and the change in the damping force of the shock absorber with respect to the piston speed is larger than that in the above case. That is, the rising of the damping force becomes steep.

When the speed of the piston further increases, the amount of fluid flowing into the communication passage increases considerably, and the second leaf valve bends together with the first leaf valve. Therefore, since it is possible to increase the change in the opening area of the communication passage with respect to the piston speed, the change in the damping force of the shock absorber with respect to the piston speed becomes gentle.

Therefore, the deflection of the second leaf valve is 2
Since there are three stages, the change in the damping force of the shock absorber has three stages.

According to the latter configuration, since the end portion of the second leaf valve bends against the urging force of the urging means, the urging means can adjust the bending manner of the leaf valve.

For example, if the biasing force of the biasing means is made relatively small, the action is similar to that of the former configuration, and the spring constant when the second leaf valve bends when the piston speed is very small. Can be increased. That is, the change in the damping force of the shock absorber with respect to the piston speed at that time can be slightly increased.

Further, if the urging force of the urging means is made large, the second leaf valve without moving the end portion of the second leaf valve by the urging force of the urging means when the piston speed is very low. Bends. That is, the change of the opening area with respect to the piston speed is small, and the damping force of the shock absorber greatly changes with respect to the piston speed. When the piston speed increases, the end portion of the second leaf valve starts to move against the urging force of the urging means, so that the opening area of the communication passage changes greatly with respect to the piston speed, and The change in the damping force of all shock absorbers becomes gradual. When the piston speed further increases and the movement of the end portion of the second leaf valve is completely regulated by the urging means, the second leaf valve and the first leaf valve flex as a unit, This is the same as when the second leaf valve and the first leaf valve are integrally bent in the former configuration.

Alternatively, depending on the urging force of the urging means and the adjustment of the leaf valve and the like, it is possible to operate as follows. That is, when the piston speed is very low, the second leaf valve bends without the end portion of the second leaf valve moving due to the urging force of the urging means, and the damping force of the shock absorber is reduced with respect to the piston speed. It changes a lot. When the piston speed increases a little, the end portion of the second leaf valve starts to move against the urging force of the urging means, and the change of the damping force of the shock absorber with respect to the piston speed becomes gradual. When the piston speed further increases, the movement of the end portion of the second leaf valve is completely regulated by the biasing means, and then the second leaf valve bends, and the damping force of the shock absorber increases again with respect to the piston speed. Change. When the piston speed is further increased, the second leaf valve and the first leaf valve are integrally bent, and the second leaf valve and the first leaf valve bend in the second configuration.
This is the same as when the leaf valve and the first leaf valve are bent together. That is, the change in the damping force of the shock absorber has four stages.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment of the present invention will be described with reference to FIG. The inside of the cylinder 2 of the shock absorber 1 is filled with hydraulic oil, and the inside of the cylinder 2 of the shock absorber 1 is filled with the piston 4 by the piston 4.
It is divided into and. The piston 4 is attached to the tip of the piston rod 3 by means of a nut 5, a stopper 9, a retainer 6 and a disc spring 7, which will be described later, a non-return valve 8 and a leaf valve 2.
1, 22 and the valve seats 10 and 11 are fixed. The piston 4 is provided with communication passages 12 and 13 that connect the upper chamber 14 and the lower chamber 15. A non-return valve 8 urged by a disc spring 7 attached via a valve seat is attached to the upper chamber 14 side of the communication passage 12. Therefore, only the hydraulic oil flowing from the lower chamber 15 to the upper chamber 14 can pass through the communication passage 12. The valve seat 11 and the piston 4 are provided on the lower chamber 15 side of the communication passage 13.
A leaf valve 22 for the middle and high speed regions, the inner peripheral side of which is sandwiched by an inner peripheral side seat surface 24, and a leaf valve 21 for the low and low speed regions which is freely supported between the leaf valve 22 and the piston 4. Are arranged. The leaf valve 21 is in contact with the seat surface 23 of the piston 4 on the outer peripheral side of the contact portion with the outer peripheral side end which is the free end of the leaf valve 22. A shoulder portion 25 is provided on the inner peripheral side seat surface 24 of the piston 4 as a stopper portion that restricts the amount of movement of the inner peripheral side end portion when the leaf valve 21 bends.

Next, the operation of the first embodiment will be described with reference to FIGS. 2a to 2c. When the shock absorber 1 extends and the piston 4 and the piston rod 3 are displaced upward in the drawing, hydraulic oil flows into the communication passage 13, and the leaf valves 21 and 22 bend due to the flow rate. At that time, when the speed of the piston 4 is very slow, that is, when the piston speed is in a very low speed range, the amount of hydraulic oil flowing into the communication passage 13 is small. Therefore, the amount of bending of the leaf valve 21 is small, and the amount of movement of the inner peripheral side end of the leaf valve 21 is small. That is, the inner peripheral side end portion of the leaf valve 21 does not contact the shoulder portion 25 of the inner peripheral side seat surface 24 of the piston 4,
The change in the opening area of the communication passage 13 with respect to the speed of the piston 4 is large. Therefore, the damping force of the shock absorber 1 changes little with respect to the piston speed, that is, the rising speed is gentle.

Next, when the speed of the piston 4 increases and the piston speed enters the low speed region, the amount of hydraulic oil flowing into the communication passage 13 increases, and the outer peripheral side of the leaf valve 21 is the outer peripheral side end of the leaf valve 22. While being brought into contact with the portion, the inner peripheral side end portion bends while being restricted by the shoulder portion 25. Therefore,
The change in the opening area of the communication passage 13 with respect to the speed of the piston 4 is smaller than when the piston speed is in the very low speed range. That is, the change of the damping force of the shock absorber 1 with respect to the piston speed becomes larger than that when the piston speed is in the very low speed range, and the damping force rises rapidly.

When the speed of the piston 4 further increases and the piston speed enters the medium and high speed range, the amount of hydraulic oil flowing into the communication passage 13 further increases, and the leaf valve 21 and the leaf valve 22 flex as a unit. Mu. Therefore, the opening area of the communication passage 13 changes largely with respect to the speed of the piston 4, and the damping force of the shock absorber 1 changes gradually.

Piston 4 obtained from the above-mentioned operation
The relationship between the speed of the shock absorber and the damping force of the shock absorber 1 is as shown in FIG.

According to the present embodiment, the flexure of the freely supported leaf valve 21 can be changed in two steps, that is, when the piston speed is in a very low speed range and when it is in a low speed range. On the other hand, it is possible to change the damping force of the shock absorber in three stages. Therefore, the damping force of the shock absorber 1 can be adjusted by changing the leaf valve 21, the shoulder 25 and the like. That is, the degree of freedom of adjusting the damping force of the shock absorber 1 can be increased, and the damping force of the shock absorber 1 can be adjusted.
Especially, the damping force can be easily adjusted when the piston speed is in a very low speed range.

Next, the second and third embodiments of the present invention will be described. FIG. 3 is a diagram showing a second embodiment of the present invention. In the present embodiment, the shoulder portion 25 and the leaf valve 21 provided on the inner peripheral side seat surface 24 of the piston 4 of the first embodiment.
A coil spring 31 is arranged between the and, as a biasing means for restricting the amount of movement of the inner peripheral side end portion of the leaf valve 21, and other configurations are the same as in the first embodiment. With such a configuration, the degree of freedom in adjusting the damping force of the shock absorber can be further increased.

The operation of the second embodiment will be described below. For example, when the spring constant of the coil spring 31 is set to be relatively small, its action is similar to that of the first embodiment. However, it is possible to increase the spring constant when the leaf valve 21 bends when the piston speed is in the very low speed range. That is, the rise of the damping force of the shock absorber 1 when the piston speed is in the extremely low speed range can be made steeper than in the first embodiment.

Next, if the spring constant of the coil spring 31 is made large, when the piston speed is very low, the inner peripheral side end of the leaf valve 21 does not move due to the urging force of the coil spring 31, and the leaf valve 21 remains. Bends. That is, the change in the opening area of the communication passage 13 is small with respect to the speed of the piston 4, and the damping force of the shock absorber 1 changes greatly with respect to the piston speed. When the piston speed increases, the inner peripheral end of the leaf valve 21 begins to move against the biasing force of the coil spring 31. Therefore, the change of the opening area of the communication passage 13 with respect to the speed of the piston 4 becomes large, and the change of the damping force of the shock absorber 1 with respect to the piston speed becomes gradual.
When the piston speed further increases and the inner peripheral side end of the leaf valve 21 compresses and contracts the coil spring 31, and the movement thereof is completely restricted, the leaf valve 21 and the leaf valve 22 flex as a unit. This is the same as when the leaf valve 21 and the leaf valve 22 are integrally bent in the first embodiment. Therefore, the damping force of the shock absorber with respect to the speed of the piston 4 changes as shown in FIG.

Alternatively, by adjusting the coil spring 31, the leaf valve 21, etc., it is possible to obtain another action as follows. That is, when the piston speed is very low, the leaf valve 21 bends without the inner end portion of the leaf valve 21 moving due to the urging force of the coil spring 31, so that the communication passage 13 with respect to the speed of the piston 4 does not move.
The change in opening area is small. Therefore, the damping force of the shock absorber 1 largely changes with respect to the piston speed. When the piston speed increases a little, the leaf valve 2
The inner peripheral side end of 1 starts to move against the biasing force of the coil spring 31. Then, the change of the opening area of the communication passage 13 with respect to the speed of the piston 4 becomes large, and the change of the damping force of the shock absorber 1 with respect to the piston speed becomes gentle. When the piston speed increases further,
The inner end portion of the leaf valve 21 has a coil spring 31.
, And its movement is completely restricted. When the leaf valve 21 further bends from that state, the change in the opening area of the communication passage 13 with respect to the speed of the piston 4 becomes small again, and the damping force of the shock absorber 1 largely changes with respect to the piston speed. When the piston speed increases further, the leaf valve 21 and the leaf valve 2
This is the same as when the leaf valve 21 and the leaf valve 22 are integrally bent in the first embodiment. That is, the change in the damping force of the shock absorber 1 is in four stages.

According to the second embodiment, the coil spring 31 can increase the degree of freedom in adjusting the damping force of the shock absorber 1, and the damping force of the shock absorber 1, particularly the piston speed, is in a very low speed range. -It is possible to further easily adjust the damping force in the low speed range.

FIG. 4 is a view showing a third embodiment of the present invention, in which a disc spring 41 is adopted in place of the coil spring 31 of the second embodiment. The operation and effect are similar to those of the second embodiment.

Further, in place of the coil spring 31, a leaf spring having a shape similar to that of a leaf valve and having a fixed inner circumference and restricting the amount of movement of the inner circumference of the leaf valve 21 may be used. The same action and effect as those of the second embodiment can be obtained.

In these embodiments, the leaf valve 22 fixed on the inner peripheral side and the leaf valve 21 whose inner peripheral side end is regulated and freely supported are used, but the outer peripheral side is used. It is also possible to use a leaf valve having a fixed valve and a leaf valve whose outer peripheral side end is restricted and which is freely supported.

[0029]

According to the present invention, one end of the freely supported second leaf valve is made to project radially from the free end of the first leaf valve having one end fixed, and the piston is formed at the protruding portion. Of the second leaf valve, the piston is provided with a stopper portion that restricts the amount of movement on the other end side when the second leaf valve is bent, or the second leaf valve is provided between the piston and the second leaf valve. Since the constitution is provided with the urging means for urging the other end side of the valve toward the first leaf valve side, the flexure of the second leaf valve changes depending on whether the piston speed of the shock absorber is in the very low speed region or the low speed region. The damping force of the shock absorber changes in three or more steps with respect to the piston speed. Therefore, the degree of freedom in adjusting the damping force of the shock absorber can be increased, and the adjustment can be facilitated.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is an operational cross-sectional view of the essential parts of the first embodiment of the present invention.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is a sectional view showing a third embodiment of the present invention.

FIG. 5 is a piston 4 according to the first embodiment of the present invention.
FIG. 4 is a graph showing the relationship between the speed of the shock absorber and the damping force of the shock absorber 1.

FIG. 6 is a graph showing the relationship between the speed of the piston 4 and the damping force of the shock absorber 1 in one example of the second embodiment of the present invention.

[Explanation of symbols]

 4 ... piston 13 ... communication passage 14 ... upper chamber (chamber) 15 ... lower chamber (chamber) 21 ... leaf valve (second leaf valve) 22 ... leaf valve (third) 1 leaf valve) 23 ・ ・ ・ seat surface 25 ・ ・ ・ shoulder (stopper) 31 ・ ・ ・ coil spring (biasing means) 41 ・ ・ ・ disc spring (biasing means)

Claims (2)

[Claims] 1. A piston that divides the interior of a cylinder into two chambers, a communication passage that is provided in the piston and that communicates the two chambers, and a communication passage that is provided in the piston and that corresponds to the speed of the piston. A valve structure of a shock absorber having a leaf valve for adjusting an opening area of the first leaf valve, the leaf valve having a first end fixed between the first leaf valve and the piston. The second leaf valve, which is freely supported and whose one end side protrudes in the radial direction from the free end portion of the first leaf valve and is in contact with the seat surface of the piston at the protrusion portion, comprises the piston, A shock absorber comprising a stopper portion for restricting a movement amount of the second leaf valve on the other end side when the second leaf valve is bent. Valve structure. 2. A valve structure for a shock absorber, comprising: a piston that divides a cylinder into two chambers; a communication passage that is provided in the piston and that communicates the two chambers; and a leaf valve that is provided in the piston. Wherein the leaf valve is freely supported between a first leaf valve whose one end is fixed and the first leaf valve and a piston, and one end side is a free end of the first leaf valve. A second leaf valve that projects in the radial direction from the portion and abuts the seat surface of the piston at the projecting portion, and the second leaf valve that is located between the piston and the second leaf valve. A valve structure for a shock absorber, comprising a biasing means for biasing an end side toward the first leaf valve side.