JPH0893828A - Hydraulic shock absorber - Google Patents

Abstract

(57) [Summary] [Object] The present invention relates to a hydraulic shock absorber suitable as a damper mechanism, and an object thereof is to make it possible to individually adjust the extension side damping force and the compression side damping force with a high degree of freedom. . [Structure] A piston rod 12 having an internal space defined by an upper chamber 34 and a lower chamber 36 is slidably inserted into a cylinder 26 filled with a fluid. At the lower end of the piston rod 12, a communication passage 16 and a communication hole 18 that connect the upper chamber 34 and the lower chamber 36 are provided. A leaf valve 20 made of an elastic material is arranged in the communication passage 16 with a predetermined inclination angle and the outer circumference of which is substantially along the inner circumference of the communication passage 16. The first pin 22 and the second pin 24, which support the reel valve 20 from the upper surface or the lower surface, are arranged at positions where a desired compression-side damping force and extension-side damping force can be realized, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic shock absorber, and more particularly to a hydraulic shock absorber suitable as a damper mechanism.

[0002]

2. Description of the Related Art Conventionally, in a shock absorber for a vehicle or the like, a piston filled with a fluid is filled with a cylinder, the internal space of which is divided into two spaces, and a communication passage which connects the two spaces. A hydraulic shock absorber is used.

In such a hydraulic shock absorber, appropriate damping force is required in each of the extension direction and the compression direction,
For example, Japanese Utility Model Laid-Open No. 60-89433 discloses a hydraulic buffer in which a single floating valve is used to form a fluid passage for expansion on the inner peripheral side of the piston and a fluid passage for compression on the outer peripheral side of the piston. Vessels are disclosed.

In this case, different damping forces can be set when the hydraulic shock absorber is extended and when the hydraulic shock absorber is compressed, and the characteristics of the vehicle shock absorber can be appropriately set according to the characteristics of the vehicle. It is possible.

[0005]

However, the above conventional hydraulic shock absorber has a structure in which the characteristics of the damping force at the time of expansion and compression thereof are both dependent on the characteristics of a single floating valve. Therefore, if the rigidity, the plate thickness, the number of sheets used, etc. of the plate material forming the floating valve are changed in order to change the damping force characteristic, both the extension side damping force and the compression side damping force will be changed.

As described above, the above-mentioned conventional structure is effective as means for individually realizing the preset expansion side damping force and compression side damping force, but the expansion side damping force and the compression side damping force are effective. However, there is a problem that the degree of freedom is extremely small when it is necessary to individually adjust the.

The present invention has been made in view of the above points, and individually adjusts the extension side damping force and the compression side damping force in the communication passage provided in the piston that defines the internal space of the cylinder. It is an object of the present invention to provide a hydraulic shock absorber that solves the above problems by providing a valve mechanism having a sufficient degree of freedom.

[0008]

The above object is to provide a cylinder having a fluid filled therein and a first inner space of the cylinder.
A partitioning member that separates the chamber and the second chamber, a communication passage that communicates the first chamber and the second chamber, and a communication member that is disposed in the communication passage with a predetermined inclination angle and has an outer periphery that is substantially the same. A valve body made of a member having elasticity along the inner circumference of the communication passage, and the valve body for supporting the valve body in a predetermined state.
This is achieved by a hydraulic shock absorber including a first support member supported from the chamber side and a second support member supported from the second chamber side.

[0009]

In the hydraulic shock absorber according to the present invention, the inside of the cylinder is filled with fluid. Therefore, when the partition member that partitions the internal space is displaced, a flow resistance is generated as the fluid flows through the communication passage.

On the other hand, the valve body is arranged in the communication passage with a predetermined inclination angle. Here, the outer periphery of the valve body is formed of a member having elasticity substantially along the inner periphery of the communication passage, and is supported by the first and second support members.

When the hydraulic shock absorber expands or contracts, a differential pressure is generated between the internal pressure of the first chamber and the internal pressure of the second chamber depending on the direction in which the hydraulic shock absorber expands or contracts. The differential pressure acts on both sides of the valve body arranged in the communication passage.

At this time, the valve body is arranged in the communication passage with a predetermined inclination angle, and when a differential pressure is generated on both surfaces thereof, one inclined end is pressed against the inner circumference of the communication passage. The other inclined end is pressed in the direction away from the inner circumference of the communication passage. As a result, when the valve body is elastically deformed and a gap is formed between the valve body and the inner periphery of the communication passage, the fluid flows through the gap to allow the expansion and contraction of the hydraulic shock absorber.

On the other hand, the valve body is the first
The first chamber is supported by the first support member from the chamber side and the second chamber is supported by the second support member from the second chamber side to maintain a predetermined state. When the pressure becomes low, the first support member functions, and in the opposite case, the second support member functions to restrict the displacement of the valve body.

Therefore, the easiness of forming a gap between the valve body and the inner circumference of the communication passage depends on the elastic characteristics of the valve body, the first support member and the second support member, respectively. It will be determined by the position of supporting the body.

Therefore, by adjusting the installation position of the first support member, the flow resistance when the fluid flows from the second chamber to the first chamber, and the installation position of the second support member are adjusted. By adjusting it, it is possible to individually adjust the flow resistance when the fluid flows from the first chamber to the second chamber, and the damping is performed with a high degree of freedom in each of the extension direction and the compression direction. It becomes possible to realize a hydraulic shock absorber in which the force can be adjusted individually.

[0016]

1 is a front sectional view showing the overall structure of a hydraulic shock absorber 10 according to an embodiment of the present invention. The hydraulic shock absorber 10 of this embodiment is configured as a shock absorber in a vehicle suspension mechanism.

In the figure, the piston rod 12 is a member connected at its upper end to a vehicle body (not shown). A valve mechanism 14 for generating an appropriate damping force in the hydraulic shock absorber 10 is provided at the lower end of the piston rod 12. Hereinafter, the configuration of the valve mechanism 14 will be described in detail with reference to FIG.

FIG. 2 is a three-view drawing of the valve mechanism 14. FIG. 2A is a front view, FIG. 2B is a side view, and FIG. 2C is a plan view.

As shown in the drawings, the valve mechanism 14 includes a communication passage 16 provided axially from the lower end of the piston rod 12, a communication hole 18 for communicating the communication passage 16 with an upper chamber 34, which will be described later, and a communication hole. Leaf valve 2 arranged in passage 16
0, the first pin 22 supporting the leaf valve 20 and the second pin 22
This is a configuration including pins 24.

Here, the leaf valve 20 is an elliptical valve made of an elastic material, and when the leaf valve 20 is arranged in the communication passage 16 at a predetermined inclination angle as shown in FIG. , Is configured to extend along the inner circumference of the communication passage 16 over the entire circumference.

Further, the first pin 22 supports the upper surface of the leaf valve 20 in a direction to bring the vicinity of the uppermost end portion of the leaf valve 20 arranged with a predetermined inclination angle into contact with the inner wall of the communication passage 16. , The second pin 24, together with the piston rod, so as to support the lower surface of the leaf valve 20 in the direction of bringing the vicinity of the lowermost end portion of the leaf valve 20 arranged with a predetermined inclination angle into contact with the inner wall of the communication passage 16. It is press-fitted into the insertion hole provided in 12.

Incidentally, hereinafter, the uppermost end and the lowermost end of the member, which are caused by giving a predetermined inclination to the disposition posture, such as the uppermost end and the lowermost end of the leaf valve 20, are generically referred to as inclined ends. I will do it.

By the way, the piston rod 12 is inserted into the cylinder 26 as shown in FIG. here,
At the upper end of the cylinder 26, a donut-shaped rod guide 30 having a bush 28 that slidably supports the piston rod 12 is provided on the inner peripheral surface thereof.

On the other hand, the piston rod 12 is provided at its lower end with a portion having a diameter larger than that of the other portions, that is, a portion corresponding to a piston. A piston band 32 that is slidable on the inner peripheral surface is wound.

Therefore, the piston rod 12 of this embodiment
Is slidably supported in the cylinder 26 at two points, the upper end of the cylinder 26 and the lower end of the piston rod 12.

As a result, the space inside the cylinder 26 is divided by the piston rod 12 into an upper chamber 34 above the piston band 32 and a lower chamber 36 below the piston band 32. That is, the upper chamber 34 and the lower chamber 36 communicate with each other through the communication passage 16 and the communication hole 18 described above.

A rebound stopper 38 is provided on the side surface of the piston rod 12 so as to contact the lower end of the rod guide 30 when the piston rod 12 reaches the extension side displacement end and regulate the subsequent displacement.

By the way, at the lower end of the cylinder 26, a valve mechanism 40 having substantially the same structure as the above-mentioned valve mechanism 14 is provided.
Is provided. Hereinafter, the configuration of the valve mechanism 40 will be described with reference to FIG. In FIG. 3, FIG. 3A is a front view, FIG. 3B is a side view,
The figure (C) has each shown the top view.

As shown in each of the drawings, the valve mechanism 40 includes the cylinder 2
The base case 42 fitted to the lower end of 6 is used as a base material. The base case 42 has a communication passage 44 axially penetrating in the center thereof, and also has a plurality of communication grooves 46 for communicating the communication passage 44 and a reservoir chamber 56 described later.

In the communication passage 44, a leaf valve 48, which is an elliptical valve made of an elastic material, is arranged at a predetermined inclination angle, like the leaf valve 20 described above. At this time, the outer circumference of the leaf valve 48 is in contact with the inner circumference of the communication passage 44 over the entire circumference.

Further, on the upper surface of the leaf valve 48, the first pin 5 press-fitted into the base case 42 so that the vicinity of the upper inclined end of the leaf valve 48 is brought into contact with the inner circumference of the communication passage 44.
0 on the lower surface of the leaf valve 48
The second pins 52 press-fitted into the base case 42 so as to bring the vicinity of the lower inclined end thereof into contact with the inner circumference of the communication passage 44 are in contact with each other.

By the way, the cylinder 26 is inserted into the outer shell 54. Here, in the cylinder 26,
As described above, the rod guide 30 is fixed to the upper end thereof and the base case 42 is fixed to the lower end thereof, and the outer circumference of the rod guide 30 and the base case 42 is fixed to the outer shell 5.
The outer shell 54, the cylinder 26, and the piston rod 12 are positioned by abutting against the inner circumference of the cylinder 4.

In this embodiment, the maximum diameter of the rod guide 30 and the maximum diameter of the base case 42 are shown in FIG.
It is designed to be sufficiently larger than the diameter of the cylinder 26 as shown in FIG.

For this reason, the cylinder 26 is replaced by the outer shell 5
4 is inserted into the cylinder 26 and the outer shell 54.
A reservoir chamber 56 having a predetermined volume is provided between and. Further, since the outer circumference having the maximum diameter of the base case 42 is in contact with the inner circumference of the outer shell 54 and the cylinder 26 is fitted in the base case 42, the cylinder 26 is positioned with respect to the outer shell 54. A lower cap 62 is fixed to the lower end of the outer shell 54 by welding, and
Is in contact with. Thereby, the communication passage 44 and the communication groove 4
6 functions as a passage that connects the lower chamber 36 and the reservoir chamber 56.

The inside of the cylinder 26 described above, that is, the inside of the upper chamber 34 and the lower chamber 36 is filled with absorber oil. The reservoir chamber 56 is appropriately filled with absorber oil in its lower space and absorber gas in its upper space.

On the other hand, a ring nut 60 having an oil seal 58 at the center is screwed onto the upper end of the outer shell 54, and is suitable for the inside of the outer shell 54 including the case where the piston rod 12 slides in the cylinder 26. Good sealing performance is ensured.

Next, the operation of the hydraulic shock absorber 10 will be described.

In the state shown in FIG. 1, when an external force in the extension direction is applied to the piston rod 12, the piston band 32 tries to slide upward with respect to the cylinder 26,
The piston rod 12 tries to displace upward. As a result, the internal pressure of the upper chamber 34 and the leaf valve 2 in the communication passage 16
0 As the internal pressure of the upper space increases, the internal pressure of the lower chamber 36,
Also, the internal pressure of the space below the leaf valve 20 in the communication passage 16 decreases.

The change in the pressure distribution is caused by the leaf valve 2
A differential pressure is generated above and below 0 to generate a force that presses the leaf valve 20 from its upper surface side to its lower surface side.

On the other hand, as described above, the leaf valve 2
0 is disposed in the communication passage 16 with a predetermined inclination angle, and of the external forces, the external force acting near the upper inclined end of the leaf valve 20 presses the leaf valve 20 against the inner wall of the communication passage 16. Acts as a force.

Therefore, when such a pressure distribution occurs,
In the vicinity of the upper inclined end of the leaf valve 20, the communication passage 16 is shut off with a stronger force than in the normal state.

On the other hand, in the vicinity of the lower inclined end of the leaf valve 20, the force pressing the leaf valve 20 from the upper surface side to the lower surface side acts in the direction of separating the leaf valve 20 from the inner wall of the communication passage 16.

Therefore, when the pressing force exceeds a predetermined level, the leaf valve 20 is elastically deformed as shown in FIG. 4, and a gap is formed between the leaf valve 20 and the inner wall of the communication passage 16.
The flow of the absorber oil from the space on the upper surface side of the leaf valve 20 toward the space on the lower surface side is allowed.

When the flow of the absorber oil is allowed in this way, the rebound stopper 38
Further displacement of the piston rod 12 is possible with the upper limit being the position where the piston abuts the rod guide 30.

By the way, regarding the extension side damping force characteristic of the hydraulic shock absorber 10, the flow rate of the absorber oil with respect to the extension side force applied to the piston rod 12 is such that the communication passage 1
It is decided depending on whether it is distributed in

Therefore, in the present embodiment, with respect to the differential pressure generated above and below the leaf valve 20, the gap of what area is the vicinity of the lower inclined end of the leaf valve 20 and the communication passage 16
The hydraulic shock absorber 10 depending on whether it is formed with the inner wall of the
The extension side damping force characteristic of is determined.

On the other hand, as described above, the leaf valve 2
0 is composed of an elastic material, and the smaller the elastic coefficient, the more easily the large-area gap can be formed. In this sense, it is clear that the elastic coefficient of the leaf valve 20 is an important factor in determining the extension side damping force characteristic of the hydraulic shock absorber 10.

On the other hand, as described above, the lower surface of the leaf valve 20 is supported by the second pin 24. Therefore,
The portion that can be elastically deformed when a differential pressure is generated above and below the leaf valve 20 is limited to the portion from the contact position of the second pin 24 to the lower inclined end. Therefore, as the second pin is located farther from the lower inclined end, a larger area can be elastically deformed, and a larger area gap can be formed for the same differential pressure.

In this sense, in this embodiment, the position of the second pin is also an important factor in determining the extension side damping force characteristic of the hydraulic shock absorber 10.

When the sectional area of the rod portion of the piston rod 12 is s and the effective sectional area of the cylinder 26 is S, when the piston rod 12 is displaced upward by the distance L, the upper chamber 34 moves to the lower chamber 36. , V = (S−s) ×
Absorber oil of L quantity flows out.

On the other hand, the piston rod 12
With the displacement, the volume of the lower chamber 36 increases by ΔV = S × L, and the amount of increase in volume cannot be covered only by the absorber oil flowing from the upper chamber 34.

In the present embodiment, the valve mechanism 40 is provided at the lower end of the cylinder 26, and the reservoir chamber 56 communicating with the valve mechanism 40 is provided in order to cope with such a phenomenon.

That is, in this embodiment, when the piston rod 12 is displaced upward as described above, and as a result, the internal pressure of the lower chamber 36 decreases, the valve mechanism 40 operates on the same principle as the valve mechanism 14 described above. Then, the appropriate amount of absorber oil flows into the lower chamber from the reservoir chamber 56.

At this time, the absorber gas is enclosed together with the absorber oil in the reservoir chamber 56, so that the absorber oil can be discharged without causing a large pressure change. Therefore, the pressure imbalance caused by the displacement of the piston rod 12 is alleviated, and an appropriate operating state can be maintained.

On the other hand, in the state shown in FIG. 1, when an external force in the compression direction is applied to the piston rod 12, the piston band 32 slides downward with respect to the cylinder 26,
That is, the piston rod 12 is displaced downward to generate a high pressure in the space below the leaf valve 20 and a low pressure in the space above the leaf valve 20. In this case, the leaf valve 20 is applied with a pressing force from its lower surface side to its upper surface side.

As a result, as described above, the piston rod 12
Contrary to the case where the leaf valve 20 is displaced in the extension direction,
The pressing force toward the inner wall of the communication passage 16 acts near the lower inclined end, and the pressing force toward the direction away from the inner wall of the communication passage 16 acts near the upper inclined end.

Therefore, when the pressing force exceeds a predetermined level, as shown in FIG. 5, the leaf valve 20 is elastically deformed to form a gap with the inner wall of the communication passage 16,
The flow of the absorber oil from the space on the lower surface side of the leaf valve 20 toward the space on the upper surface side is allowed.

When the absorber oil flow is allowed in this way, the piston rod 12 can be further displaced with the lower limit of the position where the lower end of the piston rod 12 contacts the base case 42 as the lower limit.

In this case, the compression-side damping force characteristic of the hydraulic shock absorber 10 is determined by the elastic coefficient of the leaf valve 20 and the position of the first pin 22 that supports the leaf valve 20 from the upper surface side. .

Even when the piston rod 12 is displaced in the compression direction, an unreasonable pressure imbalance is caused only by transferring the absorber oil between the upper chamber 34 and the lower chamber 36. This is the same as when 12 is displaced in the extension direction. Therefore, the piston rod 1
When 2 is displaced in the compression direction, the vicinity of the lower inclined end of the leaf valve 48 of the valve mechanism 40 is appropriately opened,
The flow of absorber oil from the lower chamber 36 toward the reservoir chamber 56 is allowed.

As described above, the hydraulic shock absorber 10 of this embodiment.
In the above, the elastic coefficient of the leaf valve 20 both affects the damping force characteristics on the extension side and the compression side, and
The disposition position of the pin 22 affects only the compression side damping force characteristic, and the disposition position of the second pin 24 affects only the extension side damping force characteristic.

Therefore, when it is necessary to individually adjust only the extension-side damping force characteristic or only the compression-side damping force characteristic, the arrangement position of the second pin 24 or the first pin 22 can be individually adjusted. If so, it is possible to appropriately realize desired characteristics.

Specifically, in FIG. 6, the second pin 24
It is possible to increase only the extension side damping force as the distance a between the disposition position of and the center line of the communication passage 16 is set larger.
Further, the larger the distance b between the disposition position of the first pin 22 and the center line of the communication passage 16 is set, the larger the compression-side damping force can be made.

In this sense, the hydraulic shock absorber 10 of this embodiment is
Has a remarkably high degree of freedom in adjusting the damping force characteristics as compared with a hydraulic shock absorber in which it is difficult to individually adjust the damping force characteristics on the extension side and the compression side. In this case, it is possible to obtain an advantage that fine tuning can be performed according to vehicle characteristics.

In addition, the valve mechanism 14 in the hydraulic shock absorber 10
Is a very simple configuration realized by disposing the leaf valve 20 in the communication passage 16. Therefore, it is easy to secure high productivity and realize cost reduction, and also has the advantage that high reliability and high durability can be secured without requiring high processing accuracy. There is.

Further, according to the structure of the hydraulic shock absorber 10, there is no danger that the leaf valve 20 will be in an attracted state, and extremely high reliability is secured as compared with a hydraulic shock absorber having a valve mechanism having a land surface. You can also enjoy the effect that you can.

As described above, it is effective to change the elastic coefficient of the leaf valve 20 when adjusting both the extension side damping force and the compression side damping force.
The same adjustment can be realized by changing the inclination angle α given to the leaf valve 20. The adjustment method will be described below.

That is, in order to reduce the inclination angle α shown in FIG. 6 and to appropriately close the communication passage 16 with the leaf valve 20, it is necessary to increase the width c of the leaf valve 20.

If the width c is increased, even if the distances b and a between the first pin 22 and the second pin 24 and the center line of the communication passage 16 are the same, the leaf valve 20 and the communication passage 16 can be more easily connected. It becomes possible to form a large gap between them, and in reality, a state similar to that when the elastic coefficient of the leaf valve 20 is lowered is realized.

By the way, in the above-mentioned embodiment, the first pins 22, 5 are used as members for supporting the leaf valves 20, 48.
Although two pins of 0 and the second pins 24 and 52 are used, the number is not limited to this, and when it is necessary to more reliably support the leaf valves 20 and 48, two pins on each side are measured. A configuration using four pins may be used.

Further, the hydraulic shock absorber 10 shown in the above embodiment.
Is based on the premise that it is applied to a vehicle shock absorber, but the applicable range is not limited to this, and it can be widely applied to a hydraulic shock absorber that constitutes a damper mechanism.

In the above embodiment, the lower end portion of the piston rod 12 and the base case 42 serve as the separating member, and the upper chamber 34, the lower chamber 36, and the reservoir chamber 56 are the above-mentioned first chamber and second chamber. The communication passage 16, the communication hole 18, the communication passage 44, and the communication groove 46 are provided in the communication passage described above, the leaf valves 20, 48 are provided in the valve body described above, and the first pins 22, 50 are provided.
Corresponds to the above-mentioned first support member, and the second pins 24 and 52 correspond to the above-mentioned second support member, respectively.

[0073]

As described above, according to the present invention, the displacement resistance of the partition member has the elastic characteristics of the valve body, and the first resistance for supporting the valve body from the first chamber side and the second chamber side, respectively. Since it is also affected by the installation positions of the support member and the second support member, the extension side damping force and the compression side damping force can be easily adjusted by individually adjusting the installation positions of the first and second support members. A hydraulic shock absorber that can be individually adjusted can be realized.

Further, according to the configuration of the present invention, there is no fear that the valve body for controlling the conduction state of the communication passage and other components are attracted to each other, and high reliability is obtained from the viewpoint of maintaining an appropriate operating state. In addition to being able to obtain the above, it is possible to enjoy the advantage of being able to suppress the generation of abnormal noise due to malfunction.

[Brief description of drawings]

FIG. 1 is a front sectional view showing the overall configuration of a hydraulic shock absorber according to an embodiment of the present invention.

FIG. 2 shows a valve mechanism 3 which is a main part of the hydraulic shock absorber of the present embodiment.
It is a side view.

FIG. 3 is a three-view drawing of a valve mechanism that is another main part of the hydraulic shock absorber of the present embodiment.

FIG. 4 is a diagram for explaining the operation of the hydraulic shock absorber of the present embodiment at the time of extension.

FIG. 5 is a diagram for explaining the operation of the hydraulic shock absorber of the present embodiment during compression.

FIG. 6 is a diagram for explaining a method of adjusting the damping force characteristic of the hydraulic shock absorber of the present embodiment.

[Explanation of symbols]

 10 Hydraulic shock absorber 12 Piston rod 14,40 Valve mechanism 16,44 Communication passage 18 Communication hole 20,48 Leaf valve 22,50 First pin 24,52 Second pin 26 Cylinder 34 Upper chamber 36 Lower chamber 42 Base case 46 Communication Groove 54 Outer shell 56 Reservoir chamber

Claims (1)

[Claims] 1. A cylinder having a fluid filled therein, a partition member for partitioning an inner space of the cylinder into a first chamber and a second chamber, and the first chamber and the second chamber communicating with each other. A communication passage, a valve body that is disposed in the communication passage with a predetermined inclination angle, and has an outer periphery that is elastic and substantially extends along the inner periphery of the communication passage, and supports the valve body in a predetermined state. Therefore, the first support member supporting the valve body from the first chamber side, and the second support member
A hydraulic shock absorber, comprising: a second support member that is supported from the chamber side.