JPH0960680A - Hydraulic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic shock absorber which requires no special jigs and is easily mounted and improves productivity when a disk valve is mounted on a piston rod. SOLUTION: A piston 20 is provided with a valve seat 20a on the bottom surface and the valve seat 20a has on the outer periphery of the seat surface 21 a projection 22 integrally formed in trapezoidal cross section having a slant plane 23 on the inner surface thereof. The projection 22 is annularly formed on the seat surface 21 and is slightly projected in the axial direction for the seat surface 21 to be a specified height. The slant plane 23 of the projection 22 is formed such that it has a specified angle θ deg. for the axis of a cylinder 1 and when a disk valve of extension side is mounted on the small diameter part of piston rod, the outer peripheral end of the check valve 10e composing the disk valve of extension side is guided along the slant surface 23 and is disposed at a predetermined position.

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 mounted on a suspension system of a vehicle such as an automobile.

[0002]

2. Description of the Related Art Conventional hydraulic shock absorbers include those shown in FIGS. 3 to 7, for example.

In FIG. 3, reference numeral 1 denotes a cylinder whose lower end side is closed and whose upper end side is open (not shown). Inside the cylinder 1, oil liquid is sealed. A piston 2 is slidably fitted inside the cylinder 1, and the inside of the cylinder 1 is divided into two upper and lower oil chambers A and B by the piston 2. Further, the lower end side of the cylinder 1 is attached to the axle side of a vehicle (not shown).

A piston ring 3 is fitted around the outer periphery of the piston 2, and the piston ring 3 plays a role of preventing oil liquid from leaking between the upper and lower oil chambers A and B. .

Reference numerals 2a and 2b are annular valve seats provided in the vicinity of the outer peripheral side of the respective end faces of the piston 2 and having a trapezoidal cross section. The valve seats 2a and 2b are provided on the inner peripheral side of the end face of the piston 2. It is provided so as to slightly project in the axial direction from the annular protrusions 4a and 4b. Further, the end surfaces of the valve seats 2a, 2b are flat seat surfaces 5a, 5b, and the contraction side disk valve 9 and the expansion side disk valve 10 described later are seated on the seat surfaces 5a, 5b. Has become.

Reference numerals 6a and 6b denote oil liquid passages that connect the upper and lower two oil chambers A and B, and the oil liquid passage 6a is an extension-side oil liquid passage, which is formed on the right side of the piston 2 in the figure. There is. The upper end of the oil liquid passage 6a opens toward the oil chamber A on the radial outer peripheral side of the valve seat 2a, and the lower end thereof opens toward the valve seat 2a.
It opens toward an annular space C formed between b and the convex portion 4b. On the other hand, the oil liquid passage 6b is a contraction side passage and is provided on the left side of the piston 2 in the figure. The upper end of the oil liquid passage 6b opens toward the annular space D formed between the valve seat 2a and the convex portion 4a, and the lower end opens toward the oil chamber B on the radially outer side of the valve seat 2b. ing.

Reference numeral 7 denotes a piston rod, and a small diameter portion 7a is formed on the lower end side of the piston rod 7. The small diameter portion 7a is penetrated through the piston 2, and a piston bolt 8 is attached from below to the end of the small diameter portion 7a. The piston 2 and the piston rod 7 are connected by being screwed into the portion. The upper end side of the piston rod 7 is extended to the outside through a rod guide, packing, etc. (not shown) that closes the upper end side opening of the cylinder 1, and is fixed to the vehicle body side of a vehicle (not shown). It has become.

Disc valves 9 and 10 are seated on and off the seat surfaces 5a and 5b of the valve seats 2a and 2b to open and close the oil liquid passages 6a and 6b at a predetermined valve opening pressure.
Is a compression side disk valve, and the disk valve 10 is an expansion side disk valve.

As shown in FIG. 4, the compression-side disk valve 9 has a notch (orifice) 9a that allows oil to be constantly communicated between the oil chambers A and B when the piston 2 moves with respect to the cylinder 1. 'Is provided on the outer peripheral portion of the cutout disk 9a, the leaf valve 9b elastically pressed against the seat surface 5a of the valve seat 2a, and the cutout disk 9a.
And a retainer 9c that determines the flow passage area of the oil liquid passage formed when the leaf valve 9b is opened,
The leaf valve 9b among them has a structure in which a plurality of sheets (four sheets) are laminated. Further, 11a is a washer which is provided on the upper end side of the piston 2 and regulates the valve opening degree of the compression side disc valve 9.

On the other hand, the extension side disc valve 10 is shown in FIG.
The retainer 10a, which is provided on the lower end side of the piston 2 and determines the flow passage area of the oil liquid passage formed when the extension side disc valve 10 is opened, as shown in FIG. A leaf valve 10b that can be elastically pressed by a notch, a notch disk 10c having a notch (orifice) 10c 'on its outer periphery, and a substantially C-shaped orifice 1.
0d 'is formed in the orifice valve 10d, the orifice 10d' of the orifice valve 10d is closed from above, and the check valve 10e that allows only the fluid communication from the oil chamber B to the oil chamber A and the outer peripheral edge portion are checked. The leaf valve 1 is composed of a shim 10f that forms an annular gap 10f ′ between the valve 10e and the inner peripheral edge thereof.
0b has a structure in which a plurality of (5) sheets are stacked. Further, 11b is a washer that is provided on the lower end side of the piston 2 and that regulates the valve opening of the extension side disc valve 10.

The hydraulic shock absorber according to the prior art has the above-mentioned structure, and its operation will be described below.

Now, suppose that the piston 2 is displaced together with the piston rod 7 in the direction of arrow X (contraction side) in FIG. As a result, the pressure inside the oil chamber B becomes high and the pressure inside the oil chamber B rises, and this pressure oil is introduced into the compression side oil liquid passage 6b and acts on the compression side disc valve 9. The pressure oil moves into the oil chamber A through the notch 9a ′ of the notch disc 9a until the pressure acting on the compression side disc valve 9 reaches a predetermined valve opening pressure. At the same time, the pressure oil passes through the notch 10c 'and the orifice 10d' of the extension side disk valve 10,
After the inner circumference side of the check valve 10e is pushed open, it moves to the oil chamber A through the annular gap 10f ′,
The orifice characteristic is changed according to the opening / closing of 0e. After that, when the pressure acting on the compression side disc valve 9 reaches a predetermined valve opening pressure, the pressure acting on the compression side disc valve 9 becomes larger than the elastic force of the compression side disc valve 9, and the outer peripheral portion thereof is elastically deformed. Then, the valve seat 2a is separated from the seat surface 5a. As a result, oil chamber B
The area of the flow path from the oil chamber to the oil chamber A increases, and the valve characteristics change.

On the other hand, when the piston 2 is opposite to the above, the arrow Y
Even when it is displaced in the direction (stretching side), the same operation as described above is performed. However, the orifice characteristic on the extension side is different in that it depends only on the notch 9a 'of the notch disk 9a which always allows the fluid communication. Also, the extension side disc valve 1
6 leaf valves 10b of 0 are laminated, whereas the leaf valve 9b of the contraction side disc valve 9 is as few as 4 laminated layers, so the valve opening pressure of the extension side disc valve 10 is on the contraction side. The valve characteristic is higher than that of the disc valve 9, and therefore, the valve characteristic is higher when the piston 2 is displaced toward the extension side than when it is displaced toward the contraction side.

[0014]

By the way, in the above-mentioned prior art, when assembling the hydraulic shock absorber, the small diameter portion 7a of the piston rod 7 is provided with the washer 11a, the compression side disc valve 9, the piston 2, the extension side disc valve. The washer 10b and the washer 11b are assembled in this order. Here, (excluding the check valve 10e of the extension side disc valve 10) is fitted to the small diameter portion 7a of the piston rod 7 to be disposed at a predetermined position. However, the extension side disc valve 10
The inner diameter of the check valve 10e that constitutes the inner diameter of the piston rod 7 is larger than the outer diameter of the shim 10f by a predetermined dimension to form the annular gap 10f ', that is, the small diameter portion 7 of the piston rod 7.
Since the diameter is set to be much larger than the diameter of a, when the check valve 10e is assembled, there is a problem that the check valve 10e is displaced in the radial direction as shown in FIG. 7, and the assembly work (positioning) is very difficult. there were. For this reason, when assembling the empty body, the worker must use a special jig to assemble it by hand, and also check whether the positioning has been completed, so that the operator can put it on the automatic assembly line. However, there is also a problem that the working time becomes long and the productivity deteriorates.

The present invention has been made in view of the above-mentioned problems of the prior art. When assembling the disc valve, a special jig is not required, the assembling work can be easily performed, and the productivity is improved. An object is to provide a hydraulic shock absorber that can be achieved.

[0016]

In order to solve the above-mentioned problems, a hydraulic shock absorber according to the present invention comprises a cylinder in which an oil liquid is sealed, and a cylinder slidably fitted in the cylinder. A piston defined by two oil chambers, a piston rod having one end connected to the piston and the other end extending to the outside of the cylinder, and an oil drilled in the piston for communicating between the oil chambers. A liquid passage, a valve seat provided on the end face of the piston, and a disc disposed on the end face of the piston to be seated on and off the seat surface of the valve seat, and which opens and closes the oil liquid passage at a predetermined valve opening pressure. In a hydraulic shock absorber including a valve, a protrusion having an inclined surface is provided on a seat surface of the valve seat, and an outer peripheral edge portion of the disc valve is guided along the inclined surface of the protrusion to form the disc. Insert the valve Characterized in that so as to disposed at a predetermined position relative to tons.

With this configuration, when the disc valve is assembled to the piston rod, the outer peripheral edge of the disc valve is guided along the inclined surface of the protrusion provided on the seat surface of the valve seat, so that the disc valve is mounted on the piston. It is arranged at a predetermined position with respect to.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG.
And it demonstrates based on FIG. The same components as those of the conventional technique are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, reference numeral 20 denotes a piston of the hydraulic shock absorber according to the present embodiment, and the piston 20 has substantially the same structure as the piston 2 of the prior art described above.

A valve seat 20a is provided on the lower end surface of the piston 20.
The valve seat 20a is integrally provided with a protrusion 22 on the outer peripheral side of the seat surface 21. The protrusion 22 is formed in an annular shape on the seat surface 21, and is provided so as to have a predetermined height by slightly protruding in the axial direction with respect to the seat surface 21.

The projection 22 has a trapezoidal radial cross section, and the base of the projection 22 (the upper valve seat 20 in the figure).
The inner peripheral diameter of (a side) is almost the same as the outer peripheral diameter of the check valve 10e that constitutes the extension side disc valve 10, and is the inner diameter of the tip end side of the protrusion 22 (the mounting direction side of the lower check valve 10e in the figure). The peripheral diameter is expanded with respect to the inner peripheral diameter of the base portion. As a result, the inner peripheral wall of the protrusion 22 is an inclined surface 23 having a predetermined angle θ ° with respect to the axial direction of the cylinder 1.

Here, the protrusion 22 is formed so as to slightly project in the axial direction with respect to the seat surface 21 so as to have a predetermined height, whereby the protrusion 22 is formed by the cutout valve 1.
Preventing the notch 10c 'of 0c from being blocked,
The orifice characteristic is ensured when the piston 20 is displaced together with the piston rod 7 toward the contracted side.

The sloping surface 23 serves as the extension side disc valve 10.
When assembled to the small diameter portion 7a of the piston rod 7, the outer peripheral edge portion of the check valve 10e that constitutes the extension side disc valve 10 is guided along the inclined surface 23. The protrusion 22 supports the outer peripheral edge portion of the check valve 10e from the radial direction at its base to prevent the check valve 10e from being displaced in the radial direction, thereby forming an annular gap 10f ′ between the check valve 10e and the shim 10f. It can be properly formed.

The inclined surface 23 of the projection 22 is formed so as to form a predetermined angle θ ° with respect to the axis of the cylinder 1. This allows the check valve to be installed when the extension side disc valve 10 is assembled. The outer peripheral edge of 10e is smoothly guided, the check valve 10e is disposed at a predetermined position, the piston 20 is displaced together with the piston rod 7 toward the extension side, and the extension side disc valve 10 reaches a predetermined valve opening pressure. At this time, the disk valve 1 extending from the seat surface 21
Although 0 is separated, the flow passage area of the oil liquid passage at this time is sufficiently secured and a predetermined damping force can be generated.

The hydraulic shock absorber according to the present embodiment has the above-mentioned structure, and the basic operation thereof is not different from that of the prior art.

However, according to this embodiment, the piston 2
Seat surface 21 of the valve seat 20a provided on the lower end surface of
Since the protrusion 22 having the inclined surface 23 is formed on the upper surface,
When the extension side disc valve 10 is assembled to the small diameter portion 7a of the piston rod 7, the outer peripheral edge portion of the check valve 10e having a diameter larger than the diameter of the small diameter portion 7a is guided by the inclined surface 23, so that it is displaced in the radial direction. Therefore, it is possible to surely dispose at a predetermined position with respect to the piston 2, that is, at a position where the annular gap 10f ′ can be appropriately formed between the piston 2 and the shim 10f.

In this embodiment, the projection is formed by the annular projection 22 having the inclined surface 23 on the seat surface 21 of the valve seat 20a. However, the shape and number of the projections are the outer peripheral edge of the disc valve. The part is guided along the inclined surface of the protrusion, and if the disk valve can be arranged at a predetermined position with respect to the piston, the invention is not limited to this.
The annular projection 22 may be partially cut out as appropriate to provide a gap. In this case, even if the height of the projection is increased, the oil liquid passage can be secured by the gap, so that the piston 2 is A predetermined damping force (orifice characteristic and valve characteristic) can be generated even if the rod 7 is displaced to the contracting side and the extending side together. Further, since the height of the protrusion is increased, the inclined surface of the protrusion can be increased, so that the check valve 10e forming the extension side disc valve 10 can be more surely arranged at a predetermined position. It will be possible.

[0028]

As described in detail above, according to the present invention,
When assembling the disc valve to the piston rod, the outer peripheral edge of the disc valve is guided along the inclined surface of the protrusion provided on the seat surface of the valve seat, so the disc valve is securely positioned at the predetermined position with respect to the piston. Can be installed at This can prevent the disc valve from being displaced in the radial direction. Moreover, the assembly work can be easily performed without the need for a special jig,
It is not necessary to check whether the disc valve has been completely positioned. Further, since it can be put on the automatic assembly line, various excellent effects such as shortening of working time and improvement of productivity can be achieved.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of the apparatus of FIG.

FIG. 3 is a vertical sectional view of a conventional technique.

FIG. 4 is a perspective view of the compression-side disc valve of FIG.

5 is a perspective view of the extension side disc valve of FIG. 3. FIG.

6 is an enlarged view of a main part of the apparatus shown in FIG. (At the time of regular assembly)

7 is an enlarged view of a main part of the apparatus shown in FIG. (At irregular assembly)

[Explanation of symbols]

 1 Cylinder 2, 20 Piston 2a Valve seat (upper end side) 2b, 20a Valve seat (lower end side) 5a Seat surface (upper end side) 5b, 21 Seat surface (lower end side) 6a Extension side oil liquid passage (oil liquid passage) 6b Compression side oil liquid passage (oil liquid passage) 7 Piston rod 9 Compression side disc valve 9a Notch disc (disc valve) 9b Leaf valve (disc valve) 9c Retainer (disc valve) 10 Extension side disc valve 10a Retainer (disc valve) 10b Leaf valve (disc valve) 10c Notched disc (disc valve) 10d Orifice valve (disc valve) 10e Check valve (disc valve) 10f Shim (disc valve) 22 Protrusion 23 Slope

Claims (1)

[Claims] 1. A cylinder containing an oil liquid, a piston slidably fitted in the cylinder to define two oil chambers in the cylinder, one end of which is connected to the piston and the other end of which is A piston rod extended to the outside of the cylinder, an oil liquid passage bored in the piston to communicate between the oil chambers, a valve seat provided on an end surface of the piston, and a valve seat of the valve seat. A hydraulic shock absorber comprising a disc valve disposed on an end surface of the piston to be seated on and seated on a seat surface, the disk valve opening and closing the oil liquid passage at a predetermined valve opening pressure. A hydraulic pressure characterized in that a protrusion portion having a protrusion is provided, the outer peripheral edge portion of the disc valve is guided along an inclined surface of the protrusion portion, and the disc valve is arranged at a predetermined position with respect to the piston. Shock absorber