JPH09177861A - Hydraulic buffer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a flow passage area by properly arranging a passage hole without lowering the strength of a piston. SOLUTION: A piston 17 coupling a piston rod 16 is fitted in a cylinder 15. A passage hole 21 on the expansion side inclined in an axial direction and a first passage hole 22 on the contraction side are alternately arranged at the piston 17 along a peripheral direction. Disc valves 23, 24 and 25 are laminated on the end face, situated downstream, of the passage hole 21 on the expansion side of the piston 17 to form oil chambers 28 and 30. Disc valves 31 and 32 are laminated on the end face, situated downstream, of the first passage hole 22 on the contraction side to form oil chambers 35 and 37. A second passage hole 42 on the contraction side paralleling an axial direction is arranged at the piston 17 and communicated with an oil chamber 37. Since a number of the second passage holes 42 on the contraction side are arranged without interfering the passage hole 21 on the expansion side, the first passage hole 22 on the contraction side, and the second passage hole 42 on the contraction side, the flow passage area of the passage hole can be increased without lowering a piston strength.

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 used for vehicles and the like.

[0002]

2. Description of the Related Art Conventionally, a hydraulic shock absorber divides the inside of a cylinder into two chambers by a piston slidably fitted in the cylinder, and communicates each cylinder chamber with a passage hole formed in the piston. The flow of the oil liquid in the passage holes due to the pressure difference of the oil liquid generated in the two spaces as the piston slides in the cylinder is transferred from a plurality of stacked disc valves arranged downstream of each passage hole. The damping force is generated by controlling the valve section.

By the way, in order to obtain a linear damping force characteristic (for example, a characteristic as shown in FIG. 5) in a hydraulic shock absorber, as shown in FIG. The piston 1 is divided into two chambers, a chamber 3 and a cylinder lower chamber 4, and an extension side passage hole 5 and a compression side passage hole 6 are formed in the piston 1 for communicating the cylinder chambers 3 and 4 with each other. The valve portions 7 and 8 disposed on the downstream side of the plurality of different outer diameters so that the valve portions 7 and 8 gradually increase in size as they approach the piston 1.
Oil chambers 9 and 10 communicating with the passage holes 5 and 6 on both end faces of the piston 1 and oil chambers 13 and 14 formed radially outward of the oil chambers 9 and 10 and communicating with throttle passages 11 and 12, respectively. And the disc valve of the valve section 7 or 8 has a large diameter as the pressure difference between the oil liquids in the cylinder chambers 3 and 4 increases (the operating speed of the piston 1 increases). A linear damping force characteristic is obtained by gradually opening from.

[0004]

However, in a small-diameter hydraulic shock absorber, it is often difficult to form a passage hole having a small piston diameter and a sufficient flow passage area. In a hydraulic shock absorber for obtaining various damping force characteristics, since the oil chambers 9 and 13 and the oil chambers 10 and 14 are arranged at different radial positions, the widths of the oil chambers 9 and 10 are set to the passage holes 5 and 6.
Is limited, and the flow passage area of the passage holes 5 and 6 cannot be taken sufficiently. And, if the flow passage area cannot be secured, the damping force generated especially in the shrinking stroke is small,
The flow of the oil liquid according to the pressure difference of the oil liquid between the two cylinder chambers 3 and 4 cannot be performed satisfactorily, and the flow rate is reduced by the passage hole 6 as shown by the broken line P in FIG. However, there is a problem in that the desired linear damping force characteristic cannot be obtained.

Therefore, if a large number of passage holes are to be provided in the piston in order to increase the flow passage area, the passage holes need to be formed so as to be inclined with respect to the axis of the piston. Further, if the passage holes are provided closer to each other in the same circumferential direction, the strength of the piston becomes weak.

Therefore, it is desired to expand the passage area of the passage hole by optimally setting the passage hole without deteriorating the strength and workability of the piston.

The present invention has been made in order to meet this demand, and an object of the present invention is to provide a hydraulic shock absorber in which passage holes are properly arranged to enlarge a flow passage area.

[0008]

The hydraulic shock absorber of the present invention comprises:
A piston slidably fitted in the cylinder divides the inside of the cylinder into two chambers, and the flow of the oil liquid is generated in the two pistons by the sliding of the piston in the cylinder. In a hydraulic shock absorber provided with a damping force generating mechanism for controlling a damping force, the damping force generating mechanism is formed so as to be inclined with respect to the axis of the piston and connects the two chambers. A first passage hole, a valve portion arranged on the downstream side of the first passage hole, and having a plurality of disc valves having different outer diameters stacked so that the piston side has a large diameter disc valve; A first oil chamber formed on the end face, the first oil chamber including a recess that is open on the downstream side of the first passage hole and the valve portion, and the piston axis at a position different from the first passage hole in the circumferential direction. Formed parallel to It is second communicating the two chambers
Second passage oil, and a second oil formed by the valve portion and a recess formed on the downstream side of the second passage hole formed radially outward of the recess forming the first oil chamber. It is characterized by being configured with a room.

With the above construction, the first passage hole is formed so as to be inclined with respect to the piston axis, the second passage hole is formed parallel to the piston axis, and the first passage hole is formed. The second passage hole is made to communicate with the second oil chamber located at a different radial outer position with respect to the first oil chamber. Even if the number of passage holes is increased, the passage holes can be arranged in the circumferential direction of the piston without interference and the flow passage area can be secured. Can be obtained.

Further, since the directions of the first passage hole and the second passage hole are different from each other, the strength of the piston is not significantly reduced, and the second passage hole is parallel to the axis of the piston. Since it is formed in a straight hole, it is easy to process and does not deteriorate workability as compared with the conventional one.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described with reference to the drawings. 1 is a longitudinal sectional view of a main part of the hydraulic shock absorber of the present embodiment, FIG. 2 is a sectional view taken along line II-II of FIG. 1, FIG. 3 is a sectional view taken along line III-III of FIG. 1, and FIG. 2's
FIG. 4 is a sectional view taken along line IV-IV.

A piston 17 mounted on a piston rod 16 is slidably fitted in the cylinder 15 via a piston ring 18, and the piston 17 allows the interior of the cylinder 15 to be a cylinder upper chamber 19 and a cylinder lower chamber. It is divided into 20 and.

Next, the damping force generating mechanism provided on the piston 17 will be described.

The piston 17 has an extension side passage hole 21 and a first contraction side passage hole (first passage hole) 22 which connect the cylinder upper chamber 19 and the cylinder lower chamber 20 to the axis of the piston 17, respectively. The extension side passage hole 21 and the first contraction side passage hole are formed so as to be inclined with respect to each other and formed in four places at 90 ° intervals in the circumferential direction.
22 and are arranged alternately at intervals of 45 ° in the circumferential direction.

On the downstream side of the extension side passage hole 21 (the end surface side of the piston 17 facing the cylinder lower chamber 20), a large diameter disc valve 23, a medium diameter disc valve 24 and a small diameter disc valve from the piston 17 side. Valve part 26 with 25 stacked in order
Are arranged. The downstream side of the extension-side passage hole 21 opens into an annular recess 27 formed in the end surface of the piston 17, and the recess 27 and the valve portion 26 form a first oil chamber 28 on the extension side. To be done.

A recess 29 is circumferentially provided at 90 ° in the radial direction outward of the annular recess 27 so as to correspond to the opening position of the extension-side passage hole 21.
4 are formed at equal intervals, and the recess 29 and the valve portion 26 form a second oil chamber 30 on the extension side. The surface on the piston 17 side with which the large-diameter disk valve 23 abuts is called the seat surface.

Downstream of the first contraction-side passage hole 22 (piston
The end of the piston 17 facing the cylinder upper chamber 19)
A valve portion 33 in which a large-diameter disk valve 31 and a small-diameter disk valve 32 are sequentially stacked from the side is provided.
Further, the downstream side of the first contraction-side passage hole 22 opens into an annular recess 34 formed in the end surface of the piston 17, and the recess 34 and the valve portion 33 form the contraction-side first oil chamber. 35 are composed.

On the radial outside of the annular recess 34, recesses 36 are formed at four positions at equal intervals of 90 ° in the circumferential direction in correspondence with the opening position of the first contraction-side passage hole 22. This recess 36
The second oil chamber 37 on the contracted side is constituted by the valve portion 33 and the valve portion 33. The recess on the opposite side of the recess 36 and the piston 17
They are arranged alternately with 29 in the circumferential direction with a deviation of 45 °. The piston with which the large-diameter disc valve 31 abuts
The surface on the 17 side is called the seat surface.

The first oil chamber 28 and the second oil chamber 30 on the extension side are communicated with each other by a throttle passage 38 formed by a notch in the seat surface formed corresponding to the opening position of the passage passage 31 on the extension side,
Similarly, the first oil chamber 35 on the contraction side and the second oil chamber 37 communicate with each other through a communication passage 39 formed by a notch on the seat surface formed corresponding to the opening position of the first contraction-side passage hole 22. Has been done. The throttle passage 38 is formed from the first oil chamber 28 to the second oil chamber 30.
The flow rate of the oil liquid flowing in the first oil chamber 28 is limited to a large amount in the second oil chamber 30 unless the flow amount is limited in order to obtain a high damping force on the extension side. And the pressure of the oil liquid in both oil chambers 28 and 30 is always the same, and only the large-diameter disk valve 23 opens to allow the oil liquid to flow, and the small-diameter disk valve 25 provides high damping force. I will not be able to.

The upstream side of the extension side passage hole 21 communicates with the cylinder upper chamber 19 by a groove-like passage 40 formed in the piston 17 and extending radially outward, and similarly, upstream of the first compression side passage hole 22. On the side, the lower chamber of the cylinder is formed by the groove-like passage 41 extending radially outward.
It is in communication with 20.

The second oil chamber 30 on the extension side is communicated with the lower cylinder chamber 20 by a fixed orifice passage 44 formed by a notch formed in the seat surface.

A second contraction-side passage hole (second passage hole) 42, which is a straight hole formed parallel to the axis of the piston 17, is opened in each of the compression-side second oil chambers 37. There is. The second compression-side passage hole 42 and the radially outwardly extending passage 43 formed in the piston 17 cause the compression-side second oil chamber.
37 and the cylinder lower chamber 20 are communicated with each other.

The groove-shaped passage 41, which communicates the first compression-side passage hole 22 and the cylinder lower chamber 20 and extends outward in the radial direction, communicates the second compression-side passage hole 42 and the cylinder lower chamber 20. Is formed deeper in the axial direction of the piston 17 than the radially outwardly extending passage 43, so that the opening of the first compression-side passage hole 22 and the opening of the second compression-side passage hole 42 do not interfere with each other. ing.

The operation of the hydraulic shock absorber having the above configuration will be described.

The first contraction-side passage hole 22 is formed so as to be inclined with respect to the axis of the piston 17, and the second contraction-side passage hole 42 is formed parallel to the axis of the piston 17 to form the first contraction side. Passage hole
Since the 22 is communicated with the first oil chamber 35 on the contraction side and the second contraction-side passage hole 42 is communicated with the second oil chamber 37 on the contraction side, the second contraction-side passage hole 42 is increased. Even each passage hole 22,
42 does not interfere with the piston in the circumferential direction of the piston 17
A large number of passage holes 22 without significantly reducing the strength of 17,
42 can be arranged. As a result, the flow passage area can be secured and the flow rate can be prevented from being restricted by the first contraction-side passage hole 22.

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

During the extension stroke of the hydraulic shock absorber, the piston 17
Rises, the pressure of the oil liquid in the cylinder upper chamber 19 becomes larger than the pressure of the oil liquid in the cylinder lower chamber 20, and first, the oil liquid in the cylinder upper chamber 1919 moves from the first oil chamber 28 on the extension side to the throttle passage 38.
Through to the second oil chamber 30 on the extension side and through the fixed orifice passage 44 to the lower cylinder chamber 20, and at that time, the damping force is generated by the fixed orifice passage 44. Then, as the pressure in the cylinder upper chamber 19 further rises, the pressures in the first oil chamber 28 and the second oil chamber 30 on the extension side also rise, and the large-diameter disk valve 23 and medium-diameter The disk valve 24 and the small diameter disk valve 25 are gradually opened in this order to generate a damping force having a linear characteristic as shown by LA in FIG.

During this extension process, each disc valve 2
Since a large damping force is generated by 3, 24, 25, the amount of oil liquid flowing in the extension side passage hole 21 is not large and the extension side passage hole 21
Even if the flow passage area of 21 is small, the expansion side passage hole 21 does not throttle the flow rate to generate the damping force of the orifice characteristic.

During the contraction stroke, the pressure of the oil liquid in the cylinder lower chamber 20 increases due to the lowering of the piston 17 due to the pressure of the oil liquid in the cylinder upper chamber 19, and initially, as in the extension stroke,
A damping force having an orifice characteristic is generated by the fixed orifice passage 44, and then the first contraction side passage hole 22 and the second contraction side passage hole 22 are formed.
The large-diameter disc valve 31 and the small-diameter disc valve 32 are gradually opened as the pressure of the oil liquid in the contraction-side passage hole 42 increases, and a damping force having a linear characteristic shown in LB of FIG. 5 is generated. .

During this contraction stroke, the first contraction-side passage hole 22
Since a large flow passage area can be secured by combining both the second contraction side passage hole 42 and the second contraction side passage hole 42, the flow rate is not throttled by the first contraction side passage hole 22 to generate the damping force of the orifice characteristic.

As described above, since the piston 17 is provided with the first contraction-side passage hole 22 and the second contraction-side passage hole 42 to ensure the passage area during the contraction stroke, the passage hole is restricted. A desired linear damping force characteristic can be obtained without generating the damping force of the orifice characteristic. Further, if there is a risk that the flow rate is also throttled in the extension side passage hole 21 to generate the damping force of the orifice characteristic, a straight hole that connects the second oil chamber 30 on the extension side and the cylinder upper chamber 19 to each other. The second extension side passage hole (not shown) may be provided.

The damping force characteristic is determined by the fixed orifice passage.
It can be set variously depending on the combination of the flow passage area of 44, the outer diameter of the disc valves 23, 24, 25, 31, 32, the plate thickness, the number of sheets, etc.
In particular, when a large damping force is required in the range where the operating speed of the piston 17 is low, the fixed orifice passage 44 is not provided, and the seat surface of the piston 17 with which the disc valves 23, 31 contact is a dish-shaped concave surface. If it is formed in such a manner that the initial deflection is given to the pressing valve portions 26, 33, it is possible to set the damping force characteristic that a high damping force is obtained in the low speed operation range of the piston 17 as shown in FIG.

Further, in this embodiment, the workability is improved as follows.

First, the second contraction side passage hole 42 is formed in the piston 17
Since it is formed parallel to the axis of the second piston, the second contraction-side passage hole 42 can be formed by a mold when the piston 17 is molded (for example, by sintering), and the workability does not deteriorate as compared with the conventional case. .

Since the throttle passage 38 and the communication passage 39 are formed in conformity with the openings on the downstream side of the extension side passage hole 21 and the first passage hole 22, the extension side passage hole is formed by diagonally forming a hole with a drill or the like. When the 21 and the first contraction-side passage hole 22 are processed, even if the opening position is shifted to the second oil chambers 30, 37 side, the holes are not processed up to the surface of the seat surface, and thus burrs may occur on the seat surface. Absent. That is, if the opening positions of the conventional expansion-side passage hole 21 and the first contraction-side passage hole 22 are deviated, the holes may be machined up to the seat surface and burr may occur on the seat surface. Is set in an open state, and a desired damping force characteristic cannot be obtained, so deburring was performed by post-processing, but this is not necessary in the present embodiment, and workability is improved.

Further, a groove-like passage 41 that communicates the upstream side of the first contraction-side passage hole 22 with the cylinder lower chamber 20 and extends outward in the radial direction.
By forming the upstream side of the second contraction-side passage hole 42 deeper than the radially outwardly extending passage 43 communicating with the cylinder lower chamber 20, the downstream sides of the passage holes 22 and 42 differ only in the circumferential direction. Even if the passage holes 22 and 42 are opened to each other, the maximum outer diameters of the passage holes 22 and 42 do not intersect with each other, and there is a margin in the distance between the passage holes 22 and 42. The range is expanded and it is not necessary to process with high accuracy, and the workability is improved.

[0037]

As described in detail above, according to the present invention, the first passage hole formed by inclining with respect to the axis of the piston and the second contraction side passage hole formed in parallel with the axis of the piston. Is opened in the first oil chamber and the second oil chamber as appropriate, the flow passage area can be expanded even in a hydraulic shock absorber having a small diameter, and the occurrence of orifice characteristics due to the restriction of the passage hole is prevented, resulting in linear damping. The force characteristic can be reliably obtained.

Further, since the passage area is enlarged so that the orifice characteristic due to the restriction of the passage hole does not occur, the pressure of the oil liquid in the cylinder chamber does not rise extremely greatly, and the cylinder and the piston rod are made liquid-tight. It is not necessary to increase the pressure resistance of a member that influences the pressure in the cylinder chamber, such as a sealing member that seals, above a preset level.

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view (cross-sectional view taken along line I-I of FIG. 2) of a main part of a hydraulic shock absorber according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG. The cylinder is omitted.

3 is a sectional view taken along line III-III in FIG. The cylinder is omitted.

4 is a sectional view taken along line IV-IV in FIG. The cylinder is omitted.

5 is a diagram showing damping force characteristics of the hydraulic shock absorber shown in FIG.

FIG. 6 is a diagram showing damping force characteristics of a hydraulic shock absorber according to another embodiment.

FIG. 7 is a longitudinal sectional view of an essential part of an example of a conventional hydraulic shock absorber.

[Explanation of symbols]

 15 Cylinder 17 Piston 19 Cylinder upper chamber 20 Cylinder lower chamber 22 First contraction side passage hole (first passage hole) 33 Valve part 35 First oil chamber 37 Second oil chamber 42 Second contraction side passage hole (Second passage hole)

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[Procedure amendment]

[Submission date] January 24, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

[0008]

The hydraulic shock absorber of the present invention comprises:
The cylinder is slidably fitted into the cylinder and
A piston that divides the inside of the binder into two cylinder chambers, and
A piston rod connected to the piston, and the piston
First recesses provided on the inner sides in the radial direction of both end faces of the
And a second recess provided radially outside the first recess.
The recess and the first recess provided on both end surfaces of the piston.
Forming a first oil chamber between the first concave portion and the second concave portion
A second oil chamber is formed between this part and the
A large-diameter disk valve that opens when the side bends,
It is laminated on the disc valve and the outer peripheral edge is the second oil.
A small diameter inside the piston in the radial direction from the outer peripheral edge of the chamber
Disc valve and its piston to its axis
The piston is sandwiched between the first oil chamber that is tilted.
And a first passage hole communicating with the cylinder chamber on the opposite side,
The piston has a position different from the first passage hole in the circumferential direction.
On both sides of the piston, installed parallel to the axis
At least one of the second oil chambers of the
And a second passage hole communicating with the opposite cylinder chamber,
A throttle passage that connects the first oil chamber and the second oil chamber
It is characterized by comprising .

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

With the above construction, the first passage hole is formed so as to be inclined with respect to the piston axis, the second passage hole is formed parallel to the piston axis, and the first passage hole is formed. The second passage hole is made to communicate with the second oil chamber located at a different radial outer position with respect to the first oil chamber. can be increased to the passage holes to secure the flow passage area and arranged in the circumferential direction of the piston without the passage hole interferes, flow by the passage holes
It is possible to prevent the amount from being reduced. In addition, large diameter
The disc valve is made by stacking small-diameter disc valves.
Therefore, the outer peripheral portion is easily bent and the inner peripheral portion is not easily bent.
Therefore, as the piston speed increases, the first oil chamber
And when the pressure in the second oil chamber rises, the
The outer circumference of the valve bends to open the outer second oil chamber
Open the throttle passage and the second passage hole, and then
The inner circumference of the disc valve and the small-diameter disc valve do not bend.
To open the first oil chamber inside and open the first oil chamber. this
In this way, open the second and first oil chambers in order, and first
Open the throttle passage and the second passage hole, and then the first passage
By opening holes and gradually increasing the flow area of the oil liquid,
Therefore , a desired linear damping force characteristic can be obtained.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction contents]

Downstream of the extension side passage hole 21 (piston 17
Of the piston 1 on the end surface side facing the cylinder lower chamber 20 of
A valve portion 26 in which a large-diameter disk valve 23, a medium-diameter disk valve 24, and a small-diameter disk valve 25 are sequentially stacked from the 7 side is provided. The downstream side of the extension side passage hole 21 is formed on the end surface of the piston 17.
The opening is formed in the annular first recess 27, and the recess 27 and the valve portion 26 form a first oil chamber 28 on the extension side.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction contents]

A second concave portion is formed radially outward of the annular concave portion 27 so as to correspond to the opening position of the extension side passage hole 21.
The locations 29 are formed at four locations at equal intervals of 90 ° in the circumferential direction, and the recesses 29 and the valve portion 26 form a second oil chamber 30 on the extension side. In addition, as shown in FIG.
The medium diameter (small diameter) disk valve 24 and small diameter
The outer peripheral ends 24A and 25A of the disc valve 25 are connected to the second oil.
Radial inner side of the piston 17 than the outer peripheral end 30A of the chamber 30
It is located in. Also, the large diameter disc valve 2
The surface on the piston 17 side with which 3 abuts is called the seat surface.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction contents]

On the downstream side of the first contraction-side passage hole 22 (the end surface side of the piston 17 facing the cylinder upper chamber 19), a large-diameter disk valve 31 and a small-diameter disk valve 32 are sequentially stacked from the piston 17 side. The valve portion 33 is provided. The downstream side of the first contraction-side passage hole 22 has an annular first concave portion formed on the end surface of the piston 17.
The section 34 be open, the first oil chamber 35 of the compression-side in this recess 34 and the valve portion 33 is formed.

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction contents]

A second recess is formed on the outer side in the radial direction of the annular recess 34 so as to correspond to the opening position of the first contraction-side passage hole 22.
The recesses 36 are formed at four positions at equal intervals of 90 ° in the circumferential direction, and the recesses 36 and the valve portion 33 form a second oil chamber 37 on the contraction side. The recesses 36 and the recesses 29 on the opposite side of the piston 17 are alternately arranged with a deviation of 45 ° in the circumferential direction. In addition,
As shown in FIG. 1, the outer peripheral end of the small-diameter disc valve 32.
32A is more fixed than the outer peripheral end 37A of the second oil chamber 37.
It is located radially inward of the carriage 17. Also, below, large diameter
The surface on the piston 17 side with which the disc valve 31 comes into contact is referred to as a seat surface.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0027

[Correction method] Change

[Correction contents]

During the extension stroke of the hydraulic shock absorber, the piston 1
7 pressure hydraulic fluid in the cylinder upper chamber 19 by the increase of greater than the pressure of the hydraulic fluid in the cylinder lower chamber 20, first, Siri
The oil liquid in the upper chamber 19 flows from the first oil chamber 28 on the extension side to the second oil chamber 30 on the extension side through the throttle passage 38 and to the lower cylinder chamber 20 via the fixed orifice passage 44. At that time, a damping force is generated by the fixed orifice passage 44. Then, as the pressure in the cylinder upper chamber 19 further increases, the pressures in the first oil chamber 28 and the second oil chamber 30 on the extension side also increase, and the large-diameter disk valve 23, the medium diameter The disc valve 24 and the disc valve 25 of small diameter are gradually opened in this order to generate a damping force having a linear characteristic as shown by LA in FIG.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0037

[Correction method] Change

[Correction contents]

[0037]

As described above in detail, according to the present invention, the first passage hole formed by inclining with respect to the axis of the piston and the second passage hole formed in parallel with the axis of the piston are provided. The first oil chamber and the second oil chamber were appropriately opened and laminated.
Large and small diameter disc valves allow piston speed
The second and first oil chambers are opened sequentially
First open the throttle passage and the second passage hole, then
Since the passage hole of No. 1 is opened, the hydraulic buffer with a small diameter is used.
The flow passage area can be expanded even in the vessel, and the generation of the orifice characteristic due to the restriction of the passage hole can be prevented, and the linear damping force characteristic can be reliably obtained.

[Procedure amendment 10]

[Document name to be amended] Drawing

[Correction target item name] Fig. 1

[Correction method] Change

[Correction contents]

FIG.

Claims (1)

[Claims] 1. A piston, which is slidably fitted in a cylinder, divides the interior of the cylinder into two chambers, and the piston has a space between the two chambers defined by sliding of the piston in the cylinder. In a hydraulic shock absorber provided with a damping force generation mechanism that controls the flow of the oil liquid that occurs in to generate a damping force, the damping force generation mechanism is formed in the piston in a manner inclined with respect to its axis.
A first passage hole communicating between the two chambers and a plurality of disc valves arranged downstream of the first passage hole and having different outer diameters are laminated so that the piston valve has a large diameter disc valve. A valve portion, a first oil chamber formed on the end surface of the piston, the first oil chamber including a concave portion that is opened on the downstream side of the first passage hole, and the valve portion; the first passage hole and the circumferential direction; A second passage hole that is formed at a different position in parallel with the axis of the piston and that communicates the two chambers, and the second passage hole that is formed radially outward of the recessed portion that forms the first oil chamber. A hydraulic shock absorber, characterized in that it comprises a second oil chamber constituted by a concave portion that is opened on the downstream side of the passage hole and the valve portion.