JPH10231879A - Hydraulic damper - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continue durability by making a sub-valve outer peripheral side adjacent to an inner peripheral side seat part free to seat and unseat a main valve outer periph eral end on and from an outer peripheral side seat part and making a support ener gized by a spring adjacent to a main valve outer peripheral side. SOLUTION: Hydraulic fluid from an extension side port 2a of a piston 2 flows to a pressure surface of a main valve 3 through an opening 3d of a sub-valve 3 and an opening 6a of a support valve 6 at the time when piston speed is fine low speed. At this time, as its hydraulic pressure is low, an outer peripheral end of a valve 4 is not bent, hydraulic fluid from the opening 6a flows in the inside of a ring groove 2e by bending an outer peripheral end of the sub-valve 3 upward around an inner peripheral side seat part 2b as its fulcrum, and extension side damping force is generated. When piston speed becomes high than low speed, hydraulic pressure of the opening 6a becomes high by a contraction effect of a passage 2f of an outer peripheral side seat part 2c, the outer peripheral end of the valve 4 is bent in such a way as to push down a support 8 by a spring 7, and the extension side damping force is generated. Consequently, as the valve 3 does not work at the time when the valve 4 works, it is possible to prevent early deterioration of valve durability.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a hydraulic shock absorber used for suppressing vehicle body vibration in a running vehicle mounted on a vehicle.

[0002]

2. Description of the Related Art There have conventionally been various proposals for a hydraulic shock absorber used for suppressing vehicle body vibration in a running vehicle mounted on a vehicle. For example, it is often proposed as an improvement of the valve structure for controlling the extension-side damping force in the piston portion.

[0003] In this case, the flow and amount of hydraulic oil acting on the valve are changed by driving an actuator externally attached to the hydraulic shock absorber or by operating a built-in position-dependent or frequency-dependent adjusting mechanism. Or to change the bending rigidity of the valve,
The overall complexity of the valve structure tends to increase the cost of the hydraulic shock absorber.

Therefore, a hydraulic shock absorber having a valve structure for generating a predetermined damping force while being assembled has been conventionally proposed.
The hydraulic shock absorber disclosed in Japanese Patent Publication No. 136 has the following valve structure.

That is, in the conventional valve structure of the piston portion of the hydraulic shock absorber, as shown in FIG. 10, the extension of the piston 2 slidably housed in the cylinder 1 is formed. On the downstream side of the side port 2a, two levels of valve seat surfaces having different height levels, that is, an inner seat portion 2b and an outer seat portion 2c are arranged in series, and each valve seat surface is The sub-valve 3 and the main valve 4, each of which is an annular leaf valve fixed at an inner peripheral end that opens with passage of hydraulic oil, are adjacent to each other.

The stamping orifice 2d is formed on the second-stage valve seat surface adjacent to the outer peripheral end of the main valve 4, that is, on the outer peripheral side seat portion 2c, so that the piston speed at which the flow rate of hydraulic oil is small is small. In the low speed range, the hydraulic oil from the extension side port 2a pushes only the sub-valve 3 open against the initial bending rigidity and passes through the stamping orifice 2d. It is said that the damping force will rise.

[0007] Further, in a low-speed region where the flow rate of the hydraulic oil increases, the hydraulic pressure in the annular groove 2e formed between the inner peripheral side seat portion 2b and the outer peripheral side seat portion 2c becomes main due to the throttle effect of the stamping orifice 2d. The initial flexural rigidity of the valve 4 will be exceeded.

As a result, after the low-speed range of the piston speed, the hydraulic oil from the expansion port 2a pushes the main valve 4 together with the sub-valve 3 to reduce the linear damping force having no orifice characteristics. Will be generated.

However, in the above-described conventional hydraulic shock absorber shown in FIG. 10, the durability of the valve structure cannot be expected, and the intended suppression of vehicle body vibration cannot be realized as set. There is concern.

That is, in the above-described conventional apparatus, since the spacer 5 is disposed between the sub-valve 3 and the main valve 4 in order to guarantee the bending of the sub-valve 3, when the piston speed becomes higher than the low speed range. The amount of deflection of the sub-valve 3 is extremely large compared to the amount of deflection when the piston speed is in a very low speed range.

Therefore, the so-called load acting on the sub-valve 3 is increased, and the sub-valve 3 is easily fatigued.
Therefore, the durability of the sub-valve 3, that is, the durability of the valve structure having the sub-valve 3 cannot be expected.

The present invention has been made in view of the above circumstances, and its object is to not only enable the suppression of vehicle body vibration, but also to maintain the durability of the valve structure. Another object of the present invention is to provide a hydraulic shock absorber which is optimal for mounting on a vehicle.

[0013]

In order to achieve the above-mentioned object, the construction of the hydraulic shock absorber according to the present invention is basically based on an extension port formed in a piston which separates an upper oil chamber and a lower oil chamber. The lower end opening is closed openably with a sub-valve,
A support valve is provided adjacent to the back of the sub-valve, a main valve is provided adjacent to the back of the support valve, each valve is formed of an annular leaf valve, and is disposed in a manner such that the inner peripheral end is fixed and the outer peripheral end is free. The outer peripheral side is detachably adjoined to the inner peripheral seat formed on the lower surface of the piston, and the outer peripheral end of the main valve is detachably adjoined to the outer peripheral seat formed on the lower surface of the piston. A support biased by a spring from behind is adjacent to the lower surface of the side,
The sub-valve has an opening communicating with the extension side port, the supporting valve communicates with the opening of the sub-valve and has an opening facing the pressure receiving surface of the main valve, and the outer peripheral ends of the sub-valve and the supporting valve have an inner peripheral side seat portion. It is assumed that it is present in the annular groove formed between the outer peripheral side seat portion and the outer peripheral side seat portion.

More specifically, the outer diameter of the support is set to be substantially the same as the outer diameter of the main valve, and the outer peripheral end of the support is located at the outer peripheral end of the adjacent main valve or the outer peripheral end of the main valve. It is assumed that a passage for communicating the annular groove to the lower oil chamber is formed in the outer peripheral side seat portion whose end is adjacent, and the outer peripheral end of the support whose outer diameter is set to be smaller than the outer diameter of the main valve is the main valve. It is assumed that it is adjacent to the lower surface on the outer peripheral side.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on one embodiment shown in the drawings. As shown in FIG.
Even in the hydraulic shock absorber according to one embodiment of the present invention,
An extension port 2 formed in a piston 2 slidably housed in a cylinder 1 and defining an upper oil chamber R1 and a lower oil chamber R2.
a has a sub-valve 3 composed of an annular leaf valve for closing the lower end opening so as to be openable, and has a main valve 4 composed of an annular leaf valve.

However, in this embodiment, the main valve 4 is assumed to be adjacent to the lower surface of the support valve 6 which is adjacent to the lower surface of the sub-valve 3, and as long as it is the same as the conventional example shown in FIG. However, it is not set to a mode in which the spacer 5 is interposed between the sub-valve 3 and the space therebetween is provided.

On the other hand, in the configuration of each of the valves 3, 4, and 6, the main valve 4 is a simple annular leaf valve, as in the above-described conventional example, whereas the sub-valve 3 is Unlike the conventional sub-valve 3 consisting of a simple annular leaf valve,
According to this embodiment, the following configuration is employed, and the support valve 6 is also configured as follows.

That is, first, as shown in FIG. 2, the sub-valve 3 is formed in a fixed portion 3a on the inner peripheral side formed in an annular shape.
And a connecting portion 3c for connecting the operating portion 3b to the fixed portion 3a, and a C-shaped opening 3d formed as a result. Have.

When the sub-valve 3 is disposed in a predetermined state, as shown in FIG.
d is maintained in a state of facing the lower end opening of the extension side port 2a.

Next, as shown in FIG. 2, the support valve 6 communicates with an opening 3d of the sub-valve 3 through an annular main body (not shown) having the same diameter as the sub-valve 3 and operates the sub-valve 3. A plurality of openings 6a (approximately in the illustrated example) in which approximately half of the outer peripheral side is concealed from above in the portion 3b
Four).

In the illustrated embodiment, a plurality of openings 6a appear at appropriate intervals.
The point is that the opening 3d of the sub-valve 3 is opposed to the upper surface of the main valve 4 to secure a necessary pressure-receiving surface in the main valve 4. Therefore, the number of the pressure-receiving surface may be arbitrary. The size, that is, the size may be arbitrary.

Each of the valves 3, 4 formed as described above
Numerals 6 are fixed to the inner peripheral end and are arranged in a form of free outer peripheral end, and as long as it is the same as in the conventional example described above, the sub-valve 3 is, in the illustrated embodiment, Instead, the outer peripheral side is detachably adjacent to an inner peripheral side seat portion 2b formed on the lower surface of the piston 2.

As described above, the support valve 6 is adjacent to the lower surface of the sub-valve 3. However, the thickness of the support valve 6 is arbitrarily determined according to the function of securing the pressure receiving surface of the main valve 4. When the thickness of the sub-valve 3 is changed while the step between the inner peripheral seat portion 2b and the outer peripheral seat portion 2c at the lower end surface of the piston 2 is kept constant, the supporting valve 6 The effect that can be dealt with only by changing the thickness of the film is produced.

While the main valve 4 is adjacent to the lower surface of the support valve 6, its outer peripheral end is removably adjacent to the outer peripheral side seat portion 2 c formed on the lower surface of the piston 2, and the lower end of the outer peripheral end is located on the lower surface of the outer peripheral end. Support 8 biased by spring 7
Are adjacent to each other.

In the illustrated embodiment, the outer diameter of the support 8 is set to be substantially the same as the outer diameter of the main valve 4, and the lower end of the spring 7 is screwed to the lower end of the piston rod 9. At the upper end, the inner peripheral end of the main valve 4 and the inner peripheral ends of the support valve 6 and the sub-valve 3 are screwed to the ridges (not shown). And a pressure-side port 2g formed in the piston 2.
Is opened and closed by a non-return valve 12.

On the other hand, a passage 2f formed by an embossed groove is formed in the outer peripheral side sheet portion 2c, and an annular groove 2e formed between the inner peripheral side sheet portion 2b and the outer peripheral side sheet portion 2c is formed in this passage. It communicates with the lower oil chamber R2 via 2f, and the outer peripheral end of the sub-valve 3 is assumed to be present in the annular groove 2e.

The passage 2f may be formed by a notched groove formed in the outer peripheral end of the main valve 4 (not shown) instead of being formed in the outer peripheral side seat portion 2c by an embossed groove. In this case, the formation of the predetermined passage is advantageous in that the operation is simplified as compared with the case where the embossed groove is formed in the piston 2.

In the hydraulic shock absorber according to this embodiment formed as described above, a predetermined damping action is performed as follows during the extension stroke in which the piston 2 rises in the cylinder 1. Become.

First, when the piston speed is very low,
As shown by an arrow a in FIG. 3, the hydraulic oil from the expansion side port 2a formed in the piston 2 reaches the pressure receiving surface side of the sub-valve 3, and the opening 3d formed in the sub-valve 3 and the support valve communicating therewith. 6 extends to the pressure receiving surface of the main valve 4 through the opening 6 a formed in the main valve 4.

At this time, since the hydraulic pressure on the pressure receiving surface of the main valve 4 is low, the outer peripheral end of the main valve 4 does not bend, and the operating oil from the opening 6a of the support valve 6 is supplied to the inner peripheral seat portion. The outer end of the sub-valve 3 is bent so as to be lifted upward with the fulcrum 2b as a fulcrum, and flows into the annular groove 2e.

The hydraulic oil which has flowed into the annular groove 2e flows out to the lower oil chamber R2 through the passage 2f formed in the outer peripheral side seat portion 2c. A predetermined extension side damping force is generated by upward bending of the outer peripheral end of the sub-valve 3 with the seat portion 2b as a fulcrum.

On the other hand, when the piston speed becomes higher than the low speed,
Due to the throttle effect in the passage 2f formed in the outer peripheral side seat portion 2c, the hydraulic pressure in the opening 6a of the support valve 6 increases,
Accordingly, the outer peripheral end of the main valve 4 bends downward so as to push down the support 8 urged by the spring 7, and the hydraulic oil flows out to the lower oil chamber R2 through a gap formed therein. The predetermined extension side damping force is generated by the bending operation of the outer peripheral end of the main valve 4 at this time.

At this time, the sub-valve 3 does not participate in the operation of the main valve 4 at all, and therefore, the bending phenomenon at the outer peripheral end does not occur.

As a result, in this embodiment, the damping force of the valve characteristics by the sub-valve 3 is reduced in the very low speed range of the piston speed, and the damping force of the valve characteristics by the main valve 4 is reduced when the piston speed becomes higher than the low speed range. It can be generated independently and in any size.

Further, in this embodiment, since the sub-valve 3 is not operated at all when the main valve 4 is operated, there is no fear of early deterioration of the valve durability due to repetition of the bending operation of the sub-valve 3, that is, in the valve structure. There is no need to worry about a decrease in durability.

As described above, in this embodiment, the sub-valve 3 performs the damping action by bending the outer peripheral end upward at a very low piston speed, and the main valve 4 at a low piston speed. Is deflected downward by bending the outer peripheral end of the sub valve 3 and the main valve 4 in a state where the sub-valve 3 and the main valve 4 are arranged in series. In contrast to the damping force action, the present embodiment is different in that the effect is a damping force action when the sub-valve 3 and the main valve 4 are arranged in parallel.

As a result, as shown in FIG.
Assuming that the characteristic indicated by the imaginary line is the case of the conventional hydraulic shock absorber shown in FIG. 10, as shown by the characteristic shown by the broken line, if the rise of the damping force in a very low speed range of the piston speed is improved, The damping force above the low speed range becomes abnormally high, and even if the steering stability is improved, the riding comfort is extremely deteriorated.

On the other hand, in the case of this embodiment, since the valves 3 and 4 are arranged in parallel and their generated damping forces can be set independently, the damping force in the very low piston speed range is reduced. Even if it is set to improve the rise,
There is no danger of abnormally high damping force at piston speeds above the low speed range.This improves steering stability when the piston speed is in the very low speed range, and improves ride comfort when the piston speed is above the low speed range. Improvements will also be possible.

FIG. 6 shows a valve structure in a piston portion of a hydraulic shock absorber according to another embodiment of the present invention, which is basically the same as that of the embodiment shown in FIG. Configuration.

Therefore, portions having the same configuration are denoted by the same reference numerals in the drawings except where necessary, and the following description will focus on features that are characteristic of this embodiment. .

That is, in this embodiment, the outer diameter of the support 8 adjacent to the lower surface of the main valve 4 is set smaller than the outer diameter of the main valve 4, and the outer peripheral end of the support 8 is It is stated that it is adjacent not to the outer peripheral end but to the lower surface on the outer peripheral side which is more inside.

On the other hand, in this embodiment, it is assumed that the outer peripheral side seat portion 2c formed on the lower surface of the piston 2 adjacent to the outer peripheral end of the main valve 4 so that it can be detached and seated is not formed with a passage 2f formed of an embossed groove. Further, a notch groove in place of the passage 2 f is not formed at the outer peripheral end of the main valve 4.

Therefore, in this embodiment, a predetermined damping action is performed as follows during the extension stroke in which the piston 2 rises in the cylinder 1.

First, when the piston speed is in the range from very low to low speed, as shown in FIG. 7, hydraulic oil from the expansion port 2a is supplied to the sub-valve 3 with the inner peripheral seat portion 2b as a fulcrum.
Flows into the annular groove 2e so as to bend the outer peripheral end upward, and the hydraulic oil in the annular groove 2e is not formed in the outer peripheral side seat portion 2c because the passage 2f (see FIG. 1) is not formed. The outer peripheral end of the support 8 is the main valve 4
Adjacent to the lower surface on the outer peripheral side of the main valve 4, that is, it is allowed to bend without being affected by the spring force of the spring 7 that urges the support 8 at the outer peripheral end of the main valve 4. The fluid flows out to the lower oil chamber R2 with its end bent.

The bending of the outer peripheral ends of the sub valve 3 and the main valve 4 at this time generates a predetermined extension damping force.

On the other hand, when the piston speed exceeds the medium speed,
The hydraulic pressure at the opening 6a of the support valve 6 increases, and therefore, as shown in FIG. 8, the main valve 4 bends downward so as to push down the support 8 urged by the spring 7, and the gap formed there is removed. Then, the fluid flows out to the lower oil chamber R2, and a predetermined extension side damping force is generated by the bending operation of the main valve 4 at this time.

At this time, the sub-valve 3 does not participate in the operation of the main valve 4 at all, and therefore, the bending phenomenon at the outer peripheral end does not occur.

Therefore, even in this embodiment,
The damping force of the valve characteristic by the sub-valve 3 and the main buckle 4 is independent from the very low to low speed range of the piston speed, and the damping force of the valve characteristic only by the main valve 4 is independent when the piston speed is higher than the middle speed region. Can be generated.

Also in this embodiment, since the sub-valve 3 is not operated at all when the main valve 4 is operated, there is no fear of early deterioration of valve durability due to repetition of the bending operation of the sub-valve 3.

On the other hand, in the case where the passage 2f is formed in the outer peripheral side seat portion 2c instead of the above, when the piston speed is in a very low speed range, as shown in FIG.
After the hydraulic oil from the opening 6a of the support valve 6 bends the outer peripheral end of the sub-valve 3 upward and flows out into the annular groove 2e, it flows out into the lower oil chamber R2 via the passage 2f. Unlike the case shown in FIG. 7, since the outer peripheral end of the main valve 4 is not bent, a lower damping force is generated on the extension side.

In the case of the embodiment shown in FIG. 9, when the piston speed becomes equal to or higher than the medium speed, the main valve 4 is supported by the spring 7 in the same manner as in the case shown in FIG. 8 is depressed so as to be depressed, and a predetermined extension side damping force is generated by the bending operation of the main valve 4 at this time.

The above description has been made by taking as an example the case where each of the valves 3, 4, 6 is disposed on the piston 2 in the cylinder 1, but from the point of view of the present invention, Although not shown, the valves 3, 4, and 6 may be used to control the compression-side damping force assuming that they are disposed in the base valve portion in the cylinder 1, and the operation and effect in that case are not different. It is.

[0053]

As described above, according to the present invention, when the piston speed is in a very low speed range, the outer peripheral end of the sub-valve bends upward without interfering with the main valve to perform a predetermined damping action. When the speed is lower than the low speed range, the main valve bends downward without involving the sub-valve and performs a predetermined damping action. In contrast to the damping action in a state where the valves are arranged in series, the present invention provides a damping action in a state where the valves are arranged in parallel.

As a result, it is possible to independently set the respective damping forces generated by the sub-valve and the main valve. In particular, while improving the rise of the damping force in a very low speed range and improving the steering stability, Above the low-speed range of the piston speed, it is possible to improve the riding comfort while suppressing the overall low damping force.

Further, according to the present invention, since the operation range of each valve is limited, it is possible to expect the durability of each valve as set, and therefore, the durability of each valve is maintained. The durability of the entire valve structure can be maintained.

In the present invention, since the operating range of each valve is limited, the damping characteristics of each valve can be set arbitrarily. Since the support valve is arranged, the configuration of the support valve is variously set,
Any attenuation characteristics can be set.

Further, according to the present invention, by setting the outer diameter of the support for carrying the main valve from below to be smaller than the outer diameter of the main valve, the spring of the spring for biasing the outer peripheral end of the main valve to the support is provided. It is possible to bend without being affected by the force, and it can be expected that a low damping force corresponding to the low speed range of the piston speed is generated.

As a result, according to the present invention, for suppressing the vehicle body vibration, it is possible to expect the generation of a preferable damping force while maintaining the durability of the valve structure.
There is an advantage that it is optimal for mounting on a vehicle.

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view showing a structure of a piston part in a hydraulic shock absorber according to the present invention.

FIG. 2 is a plan view showing a stacked state of a sub-valve, a support valve, and a main valve arranged in a piston portion.

FIG. 3 is a partially enlarged longitudinal sectional view showing an operation state of a sub-valve in a piston portion in FIG.

FIG. 4 is a view showing an operation state of a main valve in a piston portion in FIG. 1, similarly to FIG. 3;

FIG. 5 is a diagram showing characteristics of the extension damping force with respect to the piston speed by the hydraulic shock absorber of FIG. 1 in comparison with the characteristics of a conventional hydraulic shock absorber.

FIG. 6 is a view showing a structure of a piston portion in a hydraulic shock absorber according to another embodiment of the present invention, similarly to FIG.

7 is a partially enlarged longitudinal sectional view showing an operation state of a valve in a low-speed range of a piston speed in the piston section of FIG. 6;

FIG. 8 is a view showing an operation state of a valve in a middle speed region of a piston speed in the piston portion of FIG. 6, similarly to FIG. 7;

FIG. 9 is a view showing, similarly to FIG. 7, an operation state of a valve in a very low speed range of a piston speed in a piston portion in a hydraulic shock absorber according to still another embodiment of the present invention.

FIG. 10 is a view showing a structure of a piston portion in a hydraulic shock absorber as a conventional example, similarly to FIG.

[Explanation of symbols]

 Reference Signs List 2 Piston 2a Extension port 2b Inner seat 2c Outer seat 2e Annular groove 2f Passage 3 Sub-valve 3d, 6a Opening 4 Main valve 6 Support valve 7 Spring 8 Support R1 Upper oil chamber R2 Lower oil chamber

Claims (3)

[Claims] 1. A lower end opening of an extension side port formed in a piston that separates an upper oil chamber and a lower oil chamber is closed by a sub-valve so as to be openable, a support valve is provided adjacent to a back surface of the sub-valve, and a rear surface of the support valve is provided at a back surface of the support valve. The main valve is located next to the valve, each valve is formed of an annular leaf valve, and the inner peripheral end is fixed and arranged at the outer peripheral end free.The outer peripheral side of the sub-valve is separated from the inner peripheral seat formed on the lower surface of the piston. The outer peripheral end of the main valve is detachably seated adjacent to the outer peripheral seat formed on the lower surface of the piston, and the support biased by a spring from behind is adjacent to the outer peripheral lower surface of the main valve. The sub-valve has an opening communicating with the extension port, the support valve communicates with the opening of the sub-valve, and has an opening facing the pressure-receiving surface of the main valve. A hydraulic shock absorber having an outer peripheral end located in an annular groove formed between an inner peripheral side seat portion and an outer peripheral side seat portion. 2. The outer diameter of the support is set to be substantially the same as the outer diameter of the main valve, and the outer peripheral end of the support is adjacent to the outer peripheral end of the adjacent main valve or the outer peripheral end of the main valve is adjacent to the outer peripheral end of the main valve. 2. The hydraulic shock absorber according to claim 1, wherein a passage is formed in the seat portion to connect the annular groove to the lower oil chamber. 3. The hydraulic shock absorber according to claim 1, wherein the outer peripheral end of the support whose outer diameter is set smaller than the outer diameter of the main valve is adjacent to the lower surface on the outer peripheral side of the main valve.