Valve and buffer

Abstract

To provide a valve and a buffer which are hardly degraded while maintaining a smooth open-valve operation.SOLUTION: A valve V1 of the present invention includes: a valve seat member 1 having a port 1c; and a circular disk 2 with an inner circumference thereof being a fixed end and an outer circumference thereof being a free end which allows a warpage at the free end side, the disk being laminated on the valve seat member 1. The disk 2 includes arc-shaped holes h1, h2, h3 which are intermittently provided on the same circumference in a circumferential direction in three or more and having different circumferential length at a part or the whole hole. For the size of the R-form of the angled parts h1b, h2a and the R-form of the angled parts h2b, h3a on the fixed-end side that face to each other in a circumferential direction of the respective arc-shaped holes h1, h2 and the arc-shaped holes h2, h3 having different circumferential lengths, the arc-shaped holes h1,h3 having longer circumferential lengths has a larger size than the arc-shaped hole h2 having a shorter circumferential length.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a valve and a shock absorber. [Background technology]

[0002] A shock absorber is used, for example, by being interposed between the body and axle of a vehicle in order to improve the ride comfort of the vehicle, and suppresses vibration of the body and wheels by the damping force that it exerts when expanding and contracting.

[0003] Such a shock absorber may, for example, include a cylinder, a piston rod inserted into the cylinder so as to be axially movable, a piston connected to the end of the piston rod and inserted into the cylinder so as to be slidable therein, dividing the interior of the cylinder into an extension side chamber and a compression side chamber, an outer tube covering the cylinder and forming a reservoir between the outer tube and the cylinder, a valve case fitted into the end of the cylinder to divide the compression side chamber and the reservoir, and a valve consisting of the valve case and a disk stacked on the valve case to open and close a port provided in the valve case.

[0004] The valve has, for example, an annular inner periphery that is fixed to the outer periphery of a center rod that passes through the axial center of the valve case, an annular outer periphery that is positioned on the outer periphery of the inner periphery and opens and closes the port of the valve case, and a bridge that connects the inner periphery and the outer periphery; when the shock absorber extends and hydraulic oil moves from the reservoir to the compression side chamber, the bridge is significantly deflected to separate the outer periphery significantly from the port, thereby functioning as a check valve that allows the hydraulic oil to pass with almost no resistance (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Utility Model Application Publication No. 7-22147 Summary of the Invention [Problem to be solved by the invention]

[0006] In the disk of a conventional valve, a single bridge connects the inner and outer periphery, but as shown in Figure 6, a plurality of arc-shaped holes 101, 102, 103 are intermittently provided in disk 100, and a plurality of bridges 104, 105, 106 are provided between adjacent holes and the circumferential lengths of holes 101, 102, 103 are made unequal, so that the flexibility of outer periphery 107 of disk 100 is varied in the circumferential direction and the valve opens from the most flexible part, thereby making the valve-opening operation smoother.

[0007] Making the circumferential lengths of the arc-shaped holes unequal in this manner makes the disc open more smoothly, but because the outer periphery of the arc-shaped hole, which has a longer circumferential length, is farther away from the valve case than the outer periphery of the arc-shaped hole, which has a shorter circumferential length, there is a concern that stress will concentrate on the base part on the inner periphery of the bridge, which is sandwiched between the long arc and the short arc-shaped hole, making it more susceptible to deterioration.

[0008] Therefore, an object of the present invention is to provide a valve and a shock absorber that are resistant to deterioration while achieving smooth valve opening operation. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the valve of the present invention comprises a valve seat member having a port, and a disk which is annular in shape, with one of the outer and inner circumferences as a fixed end and the other of the outer and inner circumferences as a free end, with deflection on the free end side being allowed and which is stacked on the valve seat member, the disk having two or more arc-shaped holes which are arranged intermittently in the circumferential direction on the same circumference and some or all of which have different circumferential lengths, and the size of the R-shape or C-shape between the corners on the fixed end sides which face each other in the circumferential direction of the arc-shaped holes with different circumferential lengths is larger for the arc-shaped hole with a longer circumferential length than for the arc-shaped hole with a shorter circumferential length.

[0010] In a valve constructed in this manner, the circumferential lengths of some or all of the arc-shaped holes in the disk are different, so that the circumferential rigidity of the free end can be varied according to the circumferential length of the arc-shaped holes, realizing a smooth valve-opening operation. In addition, in the valve, the size of the R-shape between the corners on the fixed end sides of the circumferentially opposing arc-shaped holes of different circumferential lengths is larger for the arc-shaped hole with a longer circumferential length than for the arc-shaped hole with a shorter circumferential length, so that the width of the base on the fixed end side of the bridge between the arc-shaped holes becomes wider according to the circumferential length of the adjacent arc-shaped holes, so that the stress on the bridge can be alleviated even if a torsion is applied to the bridge.

[0011] Furthermore, the size of the R or C shape on the fixed end side of the arc-shaped hole in the disk may be increased as the circumferential length becomes longer. With a valve configured in this manner, when the disk is opened, stress due to torsion acts in addition to stress due to bending, but by increasing the size of the corners of the arc-shaped hole as the circumferential length of the arc-shaped hole becomes longer, the width of the base of the bridge to the fixed end can be optimized and stress can be efficiently alleviated.

[0012] The shock absorber of the present invention includes a cylinder, a rod inserted into the cylinder so as to be movable in the axial direction, a piston connected to the tip of the rod and inserted into the cylinder so as to be movable in the axial direction to divide the inside of the cylinder into an expansion-side chamber and a compression-side chamber, and a valve, the piston being a valve seat member and the valve being stacked on the expansion-side chamber side of the piston. The shock absorber configured in this manner can realize a smooth valve opening operation, and can reduce the stress acting on the disc to suppress deterioration, and can reduce a sudden change in damping force during contraction.

[0013] Further, another shock absorber of the present invention includes a cylinder, a rod inserted into the cylinder so as to be movable in the axial direction, a piston connected to the tip of the rod and inserted into the cylinder so as to be movable in the axial direction to divide the inside of the cylinder into an expansion side chamber and a compression side chamber, a valve case provided at the end of the cylinder to divide the compression side chamber and a reservoir formed outside the cylinder, and a valve, the valve case being a valve seat member, and the valve being stacked on the compression side chamber side of the valve case. According to the shock absorber configured in this way, it is possible to realize a smooth valve opening operation, and it is possible to reduce the stress acting on the disc to suppress deterioration, and it is possible to reduce a sudden change in the damping force during the extension operation. Effect of the Invention

[0014] According to the damping valve and shock absorber of the present invention, it is possible to suppress deterioration while smoothing the valve opening operation. [Brief description of the drawings]

[0015] [Figure 1] FIG. 1 is a vertical cross-sectional view of a shock absorber to which a valve according to an embodiment of the present invention is applied. [Diagram 2] FIG. 2 is an enlarged cross-sectional view of a piston portion to which a valve according to an embodiment of the present invention is applied. [Diagram 3] FIG. 3 is a plan view of a disk in a valve according to one embodiment of the present invention. [Figure 4] FIG. 4 is an enlarged cross-sectional view of a valve case to which a valve according to an embodiment of the present invention is applied. [Diagram 5] FIG. 5 is a plan view of another disk in a valve according to an embodiment of the present invention. [Figure 6] FIG. 6 is a plan view of a disk in a conventional valve. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] The present invention will be described below based on the embodiment shown in the drawings. As shown in FIG. 1, the valve V1 in this embodiment is applied to the piston part of the shock absorber D and is composed of a piston 1 as a valve seat member having a compression side port 1c as a port and a disk 2 stacked on the piston 1, and the valve V2 is applied to the base valve of the shock absorber D and is composed of a valve case 8 as a valve seat member having a suction port 8e as a port and a disk 9 stacked on the valve case 8. As shown in FIG. 1, the shock absorber D to which the valves V1 and V2 are applied includes a cylinder 20, a rod 21 inserted axially movably into the cylinder 20, a piston 1 connected to the tip of the rod 21, a valve case 8 provided at the lower end of the cylinder 20 in FIG. 1, a valve V1 composed of the piston 1 and the disk 2 stacked on the piston 1 with the piston 1 as the valve seat member, and a valve V2 composed of the valve case 8 and the disk 9 stacked on the valve case 8 with the valve case 8 as the valve seat member. In the case of this shock absorber D, it is installed between the body and the axle of a vehicle (not shown) and used to suppress vibrations of the body and wheels.

[0017] Hereinafter, the valves V1, V2 and each part of the shock absorber D will be described in detail. First, the shock absorber D will be described. As shown in Fig. 1, the shock absorber D includes a cylindrical cylinder 20, a rod 21 inserted into the cylinder 20 so as to be axially movable, a piston 1 connected to the tip of the rod 21 and inserted into the cylinder 20 so as to be movably movable, and a valve seat member dividing the inside of the cylinder 20 into an expansion side chamber R1 and a contraction side chamber R2 as working chambers, a bottomed cylindrical outer cylinder 22 provided on the inner periphery of the cylinder 20 and forming a reservoir R in an annular gap between the cylinder 20 and the outer cylinder 20, a valve case 8 sandwiched between the cylinder 20 and a bottom 22a of the outer cylinder 22 and dividing the cylinder 20 and the outer cylinder 22 to divide the contraction side chamber R2 and the reservoir R, a valve V1 composed of the piston 1 and a disk 2 stacked on the piston 1, and a valve V2 composed of the valve case 8 and a disk 9 stacked on the valve case 8.

[0018] 1, the upper end of the cylinder 20 is closed by an annular rod guide 23 fitted to the upper end of the outer tube 22, and the lower end is closed by fitting the valve case 8. The cylinder 20 with the rod guide 23 and the valve case 8 fitted is housed in the outer tube 22. An annular seal member 24 is laminated above the rod guide 23 in FIG. 1, and the seal member 24, the rod guide 23, the cylinder 20, and the valve case 8 are sandwiched and fixed in the outer tube 22 by a crimped portion 22b formed by crimping the upper end of the outer tube 22 in FIG. 1 from the outer periphery and a bottom portion 22a of the outer tube 22. When the cylinder 20 is inserted into the outer tube 22, an annular gap is formed between the cylinder 20 and the outer tube 22, and the annular gap forms a reservoir R for storing liquid and gas.

[0019] The rod 21 has a reduced outer diameter at the tip side, and is equipped with a small diameter section 21a having a small outer diameter at the tip side, a large diameter section 21b having an outer diameter larger than that of the small diameter section 21a and provided above the small diameter section 21a in Figure 1, a step section 21c provided at the boundary between the small diameter section 21a and the large diameter section 21b, and a screw section 21d provided on the outer periphery of the tip of the small diameter section 21a.

[0020] The rod 21 is inserted through the rod guide 23 and the inner circumference of the seal member 24 and inserted into the cylinder 20 so as to be movable in the axial direction, and a piston 1 is attached to the lower end in FIG. 1, which is the tip end, so as to be movable in the axial direction within the cylinder 20 and to divide the inside of the cylinder 20 into an expansion side chamber R1 and a compression side chamber R2. The expansion side chamber R1 and the compression side chamber R2 are filled with a liquid. The liquid filled in the shock absorber D may be hydraulic oil, water, an aqueous solution, or other liquid. A gas such as nitrogen gas or air is sealed in the reservoir R.

[0021] 1, the rod 21 protrudes out of the cylinder 20, and is provided at its upper end with a bracket (not shown) for connecting the rod 21 to one of the vehicle body and the axle of the vehicle. A bracket (not shown) is also provided on the bottom 22a of the outer cylinder 22, and the outer cylinder 22 is connected to the other of the vehicle body and the axle via the bracket (not shown). The shock absorber D is used by being interposed between the vehicle body and the axle, and when the vehicle runs on an uneven road surface and the wheels vibrate up and down relative to the vehicle body, the rod 21 moves in and out of the cylinder 20, the shock absorber D expands and contracts, and the piston 1 moves up and down (axially) within the cylinder 20.

[0022] 2, the piston 1 serving as a valve seat member constituting the valve V1 is fitted onto the outer periphery of the small diameter portion 21a of the rod 21, and is fixed to the rod 21 by a piston nut 7 screwed onto a threaded portion 21d of the rod 21. The piston 1 is also attached to the rod 21, and its outer periphery is brought into sliding contact with the inner periphery of the cylinder 20, dividing the inside of the cylinder 20 into an expansion-side chamber R1 and a compression-side chamber R2 serving as working chambers.

[0023] The piston 1 includes an annular main body portion 1a, an expansion-side port 1b that opens from the outer periphery of the upper end of the main body portion 1a in FIG. 2 and passes vertically through the main body portion 1a to reach the lower end of the main body portion 1a in FIG. 2, a compression-side port 1c that is arranged on the outer periphery side of the expansion-side port 1b with respect to the main body portion 1a and opens from the outer periphery of the lower end of the main body portion 1a in FIG. 2 and passes vertically through the main body portion 1a to reach the upper end of the main body portion 1a in FIG. 2, an annular expansion-side seat portion 1d that protrudes downward from the lower end of the main body portion 1a in FIG. 2 to surround the outer periphery of the expansion-side port 1b and is arranged on the inner periphery side of the compression-side port 1c, and an annular compression-side seat portion 1e that protrudes upward from the upper end of the main body portion 1a in FIG. 2 to surround the outer periphery of the compression-side port 1c.

[0024] 2, the extension-side leaf valve 3 is laminated below the piston 1. The extension-side leaf valve 3 is a laminated leaf valve formed by laminating a plurality of annular plates, and is laminated at the lower end of the piston 1 as a valve seat member in FIG. 2, and is fixed to the outer periphery of the small diameter portion 21a of the rod 21 together with the piston 1. The inner periphery of the lowermost annular plate of the extension-side leaf valve 3 is in contact with the extension-side seat portion 1d, and is allowed to bend in a direction away from the piston 1 on the outer periphery, causing the outer periphery to be seated on and removed from the extension-side seat portion 1d.

[0025] When the expansion-side leaf valve 3 has its outer circumferential side seated on the expansion-side seat portion 1d, it closes the outlet end of the expansion-side port 1b. When the pressure from the expansion-side port 1b bends the outer circumferential side and moves it away from the expansion-side seat portion 1d, it opens the expansion-side port 1b and provides resistance to the flow of liquid passing through the gap between it and the expansion-side seat portion 1d.

[0026] In addition, an annular disk 2 is stacked above the piston 1 in FIG. 2. As shown in FIG. 3, the disk 2 is annular and has arc-shaped holes h1, h2, and h3 that are provided intermittently in the circumferential direction on the same circumference in the radial center. In this way, the disk 2 has three arc-shaped holes h1, h2, and h3, so that the disk 2 has an annular outer peripheral portion 2a on the outer periphery of the arc-shaped holes h1, h2, and h3, an annular inner peripheral portion 2b arranged inside the outer peripheral portion 2a on the inner periphery side of the arc-shaped holes h1, h2, and h3, and three bridges 2c, 2d, and 2e that connect the inner circumference of the outer peripheral portion 2a to the outer circumference of the inner peripheral portion 2b between the arc-shaped holes h3 and h1, between the arc-shaped holes h1 and h2, and between the arc-shaped holes h2 and h3.

[0027] The circumferential lengths of the arc-shaped holes h1, h3 are both equal and longer than the circumferential length of the arc-shaped hole h2, and the distance between the bridge 2c between the arc-shaped holes h1, h3 and the bridge 2d between the arc-shaped holes h1, h2 is equal to the distance between the bridge 2c between the arc-shaped holes h1, h3 and the bridge 2e between the arc-shaped holes h2, h3 and is wider than the distance between the bridges 2d, 2e.

[0028] The disk 2 has an inner periphery 2b fitted onto the outer periphery of the small diameter portion 21a of the rod 21, and is fixed in a stacked state on the piston 1 by a cylindrical collar 4 which is also fitted onto the outer periphery of the small diameter portion 21a and stacked on the opposite piston side of the disk 2. In this manner, the disk 2 is stacked on the upper end of the piston 1 in FIG. 2 with the inner periphery 2b as the fixed end and the outer periphery 2a as the free end. Also, a spring 5 arranged on the outer periphery of the collar 4 is stacked on the opposite piston side of the disk 2.

[0029] The spring 5 is a conical spring interposed between a spring bearing 6, which is the outer periphery of the small diameter portion 21a and is sandwiched between the collar 4 and the step portion 21c, and the outer periphery 2a of the disk 2, and constantly exerts a biasing force that presses the outer periphery 2a toward the compression-side seat portion 1e. Note that the spring 5 is not limited to a conical spring, and may be a disc spring, a wave washer, or another elastic body, as long as it can exert an appropriate biasing force to bias the outer periphery 2a of the disk 2 toward the compression-side seat portion 1e.

[0030] The aforementioned spring retainer 6, collar 4, spring 5, disc 2, piston 1 and extension side leaf valve 3 are successively assembled to the outer periphery of the small diameter portion 21a of the rod 21, and then are fixed to the rod 21 by being clamped between the piston nut 7, which is screwed to the threaded portion 21d of the small diameter portion 21a, and the step portion 21c of the rod 21.

[0031] The outer peripheral portion 2a of the disk 2 attached to the small diameter portion 21a of the rod 21 together with the piston 1 can be seated on and removed from the compression-side seat portion 1e, and when seated on the compression-side seat portion 1e, it closes the compression-side port 1c, and when separated from the compression-side seat portion 1e, it opens the compression-side port 1c. Even when the outer peripheral portion 2a of the disk 2 is seated on the compression-side seat portion 1e, the arc-shaped holes h1, h2, and h3 of the disk 2 face the upper opening end of the expansion-side port 1b in the axial direction in FIG. 1, and communication between the expansion-side port 1b and the expansion-side chamber R1 is ensured through the arc-shaped holes h1, h2, and h3. In addition, since the disk 2 is biased by the spring 5, when the outer circumferential portion 2a is separated from the compression-side seat portion 1e and then returns to a position where it abuts against the compression-side seat portion 1e again, the disk 2 is able to quickly return to a position where it abuts against the compression-side seat portion 1e by receiving the biasing force of the spring 5 and can tightly close the compression-side port 1c by being in close contact with the compression-side seat portion 1e, but if the biasing force of the spring 5 is not necessary, the spring 5 and the spring retainer 6 may be eliminated. In that case, since there is no need to provide the spring 5, a thin, small-diameter spacer or a spacer may be provided instead of the collar 4 for securing the axial space for arranging the spring 5.

[0032] When the pressure in the compression side chamber R2 is higher than the pressure in the expansion side chamber R1, the disk 2 in the valve V1 receives the pressure in the compression side chamber R2 and brings the outer periphery 2a into close contact with the compression side seat portion 1e to close the compression side port 1c. On the other hand, when the pressure in the compression side chamber R2, which is upstream of the compression side port 1c, becomes higher than the pressure in the expansion side chamber R1, the bridges 2c, 2d, and 2e of the disk 2 are bent and the spring 5 is contracted to separate the outer periphery 2a from the compression side seat portion 1e, opening the compression side port 1c and allowing the flow of liquid from the compression side chamber R2 to the expansion side chamber R1 with almost no resistance.

[0033] As described above, when the pressure of the compression-side chamber R2, which is upstream of the compression-side port 1c acting on the outer peripheral portion 2a, becomes equal to or greater than the valve-opening pressure, the bridges 2c, 2d, and 2e of the disk 2 are deflected to separate the outer peripheral portion 2a from the compression-side seat portion 1e. If the bridges 2c, 2d, and 2e are deflected when the outer peripheral portion 2a receives the pressure of the compression-side chamber R2, the bridge 2c between the arc-shaped holes h1 and h3 is deflected in response to the force that separates the outer peripheral portion 2a from the compression-side seat portion 1e due to the pressure acting in the range from the center of the arc-shaped hole h1 of the outer peripheral portion 2a in the circumferential direction to the center of the arc-shaped hole h3 in the circumferential direction. Similarly, the bridge 2d between the arc-shaped holes h1 and h2 is deflected in response to the force acting on the outer peripheral portion 2a from the compression-side seat portion 1e by the pressure acting on the range from the circumferential center of the arc-shaped hole h1 of the outer peripheral portion 2a to the circumferential center of the arc-shaped hole h2 of the outer peripheral portion 2a. Furthermore, the bridge 2e between the arc-shaped holes h2 and h3 is deflected in response to the force acting on the outer peripheral portion 2a from the compression-side seat portion 1e by the pressure acting on the range from the circumferential center of the arc-shaped hole h2 of the outer peripheral portion 2a to the circumferential center of the arc-shaped hole h3 of the outer peripheral portion 2a. Therefore, when the bridges 2c, 2d, and 2e are deflected by the pressure of the compression-side chamber R2 on the outer peripheral portion 2a, the bridge 2c that receives the largest force among the bridges 2c, 2d, and 2e is deflected more than the bridges 2d and 2e.

[0034] In addition, the rigidity of the outer peripheral portion 2a is lower in the circumferential direction at the outer peripheral portions of the arc-shaped holes h1 and h3 where the bridge interval is wider, and is higher at the outer peripheral portion of the arc-shaped hole h2 where the bridge interval is narrower. Therefore, the rigidity of the outer peripheral portion 2a is lowest near the circumferential center of the arc-shaped hole h1 and near the circumferential center of the arc-shaped hole h3, and when the outer peripheral portion 2a is subjected to the pressure of the compression-side chamber R2, the portions with low rigidity in the circumferential direction are largely separated from the compression-side seat portion 1e and deform in a wavy manner in the circumferential direction.

[0035] For this reason, the bridge 2d (2e) arranged between the outer peripheral portion of the arc-shaped hole h2, which is the least likely to separate from the compression-side seat portion 1e in the outer circumferential portion 2a, and the outer peripheral portion near the center of the arc-shaped hole h1 (h3), which is the most likely to separate, is not only bent but also twisted due to the undulating deformation of the outer circumferential portion 2a, so that a large stress acts on the base of the bridge 2d (2e) to the inner circumferential portion 2b, which is the side of the arc-shaped hole h1 (h3).

[0036] To address this issue, in the disk 2 of the valve V1 of this embodiment, the size of the R-shape of the corners h1b and h2a on the inner peripheral portion 2b side, which are the fixed ends facing each other in the circumferential direction of the arc-shaped holes h1 and h2 having different circumferential lengths, is made larger for the corner h1b of the arc-shaped hole h1, which has a longer circumferential length, than for the corner h2a of the arc-shaped hole h2, which has a shorter circumferential length. In this case, since the corners h1b and h2a are molded into an R-shape, the radius of the R-shape of the corner h1b of the arc-shaped hole h1 is made larger than the radius of the R-shape of the corner h2a of the arc-shaped hole h2, and the width of the arc-shaped hole h1 side of the base of the bridge 2d to the inner peripheral portion 2b is widened to alleviate stress concentration. In the disk 2, the size of the R-shape of the corners h2b, h3a on the inner peripheral portion 2b side, which are the fixed ends facing each other in the circumferential direction of the arc-shaped holes h2, h3 having different circumferential lengths, is made larger for the corner h3a of the arc-shaped hole h3 having a longer circumferential length than for the corner h2b of the arc-shaped hole h2 having a shorter circumferential length. In this case, since the corners h2b, h3a are R-shaped, the radius of the R-shape of the corner h3a of the arc-shaped hole h3 is made larger than the radius of the R-shape of the corner h2b of the arc-shaped hole h2, and the width of the arc-shaped hole h2 side of the base of the bridge 2e to the inner peripheral portion 2b is widened to alleviate stress concentration.

[0037] The size of the R-shape of the corners h1a and h3b on the inner periphery 2b side, which are the fixed ends facing each other in the circumferential direction of the arc-shaped holes h1 and h3 having the same circumferential length, is the same as that of the R-shape of the corners h1b and h3a, and the width of the base of the bridge 2c to the inner periphery 2b is made wider. This is intended to relieve the stress at the base of the bridge 2c, since when the bridges 2c, 2d, and 2e are deflected by the pressure of the compression side chamber R2 in the outer periphery 2a, the amount of torsion in the bridge 2c is small but the amount of deflection is the largest among the bridges 2c, 2d, and 2e. Since the bridge 2c is unlikely to be twisted due to the circumferential deformation of the outer periphery 2a, the size of the R-shape of the corners h1a and h3b may be smaller than that of the R-shape of the corners h1b and h3a.

[0038] In this way, the longer the circumferential length of the arc-shaped holes h1, h2, h3, the wider the installation interval of the bridges 2c, 2d, 2e and the lower the rigidity of the outer circumferential portion 2a of the disk 2. Therefore, when the disk 9 is opened, the bridges 2c, 2d, 2e are subjected to stress due to torsion in addition to stress due to bending. However, the size of the R-shape of the corners h1a, h1b, h2a, h2b, h3a, h3b of the arc-shaped holes h1, h2, h3 is larger for the corners h1a, h1b, h3a, h3b of the arc-shaped holes h1, h3, which have a longer circumferential length, than for the corners h2a, h2b of the arc-shaped hole h2, which has a shorter circumferential length. As a result, the width of the root of the inner circumferential portions 9b of the bridges 2d, 2e between the arc-shaped holes h1, h3, which have a longer circumferential length, and the arc-shaped hole h2, which has a shorter circumferential length, is increased, thereby alleviating the stress.

[0039] 4, the valve case 8 as a valve seat member constituting the valve V2 comprises an annular main body portion 8a which fits onto the inner periphery of the lower end of the cylinder 20, an annular flange portion 8b which is connected to the outer periphery of the lower end of the main body portion 8a and faces the lower end of the cylinder 20, a plurality of notches 8c which open from the lower end of the flange portion 8b in FIG. 4, a discharge port 8d which opens from the outer periphery of the upper end of the main body portion 8a in FIG. 4, passes through the main body portion 8a from top to bottom, and leads to the lower end of the main body portion 8a in FIG. 4 and surrounding the outer periphery of the discharge port 8d and is located more radially outward than the suction port 8e; and the main body portion 8a is provided with a suction port 8e which opens from the outer periphery of the lower end of the main body portion 8a in Figure 4, penetrates vertically through the main body portion 8a and leads to the upper end of the main body portion 8a in Figure 4, an annular discharge side seat portion 8f which protrudes downward from the lower end of the main body portion 8a in Figure 4 and surrounds the outer periphery of the discharge port 8d and is located more radially inward than the suction port 8e, and an annular suction side seat portion 8g which protrudes upward from the upper end of the main body portion 8a in Figure 4 and surrounds the outer periphery of the suction port 8e.

[0040] 4, the valve case 8 is fixed to the cylinder 20 and the outer cylinder 22 by fitting the outer periphery of the main body 8a to the inner periphery of the lower end of the cylinder 20 and by sandwiching the flange 8b between the lower end of the cylinder 20 and the bottom 22a of the outer cylinder 22, and separates the pressure side chamber R2 in the cylinder 20 from the reservoir R between the cylinder 20 and the outer cylinder 22. An exhaust port 8d and a suction port 8e in the valve case 8 are communicated with the pressure side chamber R2 in the cylinder 20 and are also communicated with the reservoir R via a notch 8c formed in the flange 8b.

[0041] Next, the contraction-side leaf valve 10 is stacked on the lower side of the valve case 8 in FIG. 4. The contraction-side leaf valve 10 is a stacked leaf valve formed by stacking a plurality of annular plates, and is stacked on the lower end of the valve case 8 as a valve seat member in FIG. 4, and its inner periphery is fixed to the outer periphery of the center rod 11 inserted into the inner periphery of the main body 8a of the valve case 8. In addition, the contraction-side leaf valve 10 has the inner periphery side of the lowermost annular plate abutted against the discharge-side seat portion 8f, and is allowed to bend in a direction away from the valve case 8 on the outer periphery side, and the outer periphery side is seated on and removed from the discharge-side seat portion 8f. The center rod 11 is cylindrical with a flange 11a at the upper end in FIG. 4, and has a flange 11b formed by folding back the outer periphery at the lower end in FIG. 4, and a step portion 11c at the upper part in FIG. 4 near the flange 11a. The center rod 11 fixes the valve case 8, the compression side leaf valve 10, and the annular disk 9, which are attached to the outer periphery, by sandwiching them between the step portion 11c and the flange 11b.

[0042] When the compression side leaf valve 10 has its outer circumferential side seated on the discharge side seat portion 8f, it blocks the outlet end of the discharge port 8d. When the pressure from the discharge port 8d side causes the outer circumferential side to bend and move away from the discharge side seat portion 8f, it opens the discharge port 8d and provides resistance to the flow of liquid passing through the gap between it and the discharge side seat portion 8f.

[0043] In addition, an annular disk 9 is stacked on the upper side of the valve case 8 in FIG. 4. As shown in FIG. 5, the disk 9 is annular and has arc-shaped holes h4, h5, and h6 that are provided intermittently in the circumferential direction on the same circumference in the radial center. In this way, the disk 9 has three arc-shaped holes h4, h5, and h6, so that the disk 9 has an annular outer peripheral portion 9a on the outer periphery of the arc-shaped holes h4, h5, and h6, an annular inner peripheral portion 9b arranged inside the outer peripheral portion 9a on the inner periphery side of the arc-shaped holes h4, h5, and h6, and three bridges 9c, 9d, and 9e that connect the inner circumference of the outer peripheral portion 9a to the outer circumference of the inner peripheral portion 9b between the arc-shaped holes h6 and h4, between the arc-shaped holes h4 and h5, and between the arc-shaped holes h5 and h6.

[0044] The circumferential lengths of the arc-shaped holes h4, h5, and h6 are all different, with the arc-shaped hole h6 being the longest, followed by the arc-shaped hole h4, and the arc-shaped hole h5 being the shortest. Therefore, the distance between the bridge 9c between the arc-shaped holes h4 and h6 and the bridge 9e between the arc-shaped holes h5 and h6 is the widest, the distance between the bridge 9c between the arc-shaped holes h4 and h6 and the bridge 9d between the arc-shaped holes h4 and h5 is the second widest, and the distance between the bridges 2d and 2e is the narrowest.

[0045] The disks 9 have their inner periphery 9b fitted onto the outer periphery of the center rod 11, and are fixed in a stacked state on the valve case 8 by a step 11c of the center rod 11. In this manner, the disks 9 are stacked on the upper end of the valve case 8 in FIG. 4, with their inner periphery 9b serving as the fixed end and their outer periphery 9a serving as the free end. In addition, a spring 13, which is disposed on the outer periphery of the center rod 11, is stacked on the opposite piston side of the disks 9.

[0046] The spring 13 is a conical spring that is disposed on the outer periphery between the step portion 11c of the center rod 11 and the flange 11a, and is interposed between the flange 11a and the outer periphery 9a of the disk 9, and constantly exerts a biasing force that presses the outer periphery 9a toward the suction side seat portion 8g. Note that the spring 13 is not limited to a conical spring, and may be a disc spring, a wave washer, or another elastic body, as long as it can exert an appropriate biasing force to bias the outer periphery 9a of the disk 9 toward the suction side seat portion 8g.

[0047] The outer peripheral portion 9a of the disk 9, which is attached to the outer periphery of the center rod 11 together with the valve case 8, can be seated on and removed from the suction side seat portion 8g, and closes the suction port 8e when seated on the suction side seat portion 8g, and opens the suction port 8e when separated from the suction side seat portion 8g. Even when the outer peripheral portion 9a of the disk 9 is seated on the suction side seat portion 8g, the arc-shaped holes h4, h5, and h6 axially face the opening end at the upper end of the suction port 8e in Figure 4, and communication between the exhaust port 8d and the compression side chamber R2 is ensured via the arc-shaped holes h4, h5, and h6. In addition, since the disc 9 is biased by the spring 13, after the outer circumferential portion 9a moves away from the suction side seat portion 8g, when it returns to a position where it abuts against the suction side seat portion 8g again, it is able to quickly return to a position where it abuts against the suction side seat portion 8g by receiving the biasing force of the spring 13 and to closely contact the suction side seat portion 8g to tightly close the suction port 8e. However, if the biasing force of the spring 13 is not necessary, the spring 13 may be eliminated.

[0048] When the pressure in the pressure-side chamber R2 is higher than the pressure in the reservoir R, the disk 9 in the valve V2 receives the pressure in the pressure-side chamber R2 and brings the outer periphery 2a into close contact with the suction-side seat portion 8g to close the suction port 8e. On the other hand, when the pressure in the reservoir R, which is upstream of the suction port 8e, becomes higher than the pressure in the pressure-side chamber R2, the bridges 9c, 9d, and 9e of the disk 9 are bent and the spring 13 is contracted to separate the outer periphery 9a from the suction-side seat portion 8g, opening the suction port 8e and allowing the flow of liquid from the reservoir R to the pressure-side chamber R2 with almost no resistance.

[0049] As described above, when the pressure of the reservoir R upstream of the suction port 8e acting on the outer circumferential portion 9a becomes equal to or greater than the valve opening pressure, the bridges 9c, 9d, and 9e of the disk 9 are deflected to separate the outer circumferential portion 9a from the suction-side seat portion 8g. If we consider a case in which the bridges 9c, 9d, and 9e are deflected when the outer circumferential portion 9a is subjected to the pressure of the reservoir R, the bridge 9c between the arc-shaped holes h4 and h6 is deflected in response to a force that separates the outer circumferential portion 9a from the suction-side seat portion 8g due to the pressure acting on the range from the circumferential center of the arc-shaped hole h4 of the outer circumferential portion 9a through the bridge 9c to the circumferential center of the arc-shaped hole h6. Similarly, the bridge 9d between the arc-shaped holes h4 and h5 is deflected in response to the force acting on the range from the circumferential center of the arc-shaped hole h4 of the outer peripheral portion 9a through the bridge 9d to the circumferential center of the arc-shaped hole h5 of the outer peripheral portion 9a, which causes the outer peripheral portion 9a to move away from the suction-side seat portion 8g. Furthermore, the bridge 9e between the arc-shaped holes h5 and h6 is deflected in response to the force acting on the range from the circumferential center of the arc-shaped hole h5 of the outer peripheral portion 9a through the bridge 9e to the circumferential center of the arc-shaped hole h6 of the outer peripheral portion 9a, which causes the outer peripheral portion 9a to move away from the suction-side seat portion 8g. Therefore, when the outer peripheral portion 9a is subjected to the pressure of the compression-side chamber R2 and each bridge 9c, 9d, and 9e is deflected, the bridge 9c that receives the largest force among the bridges 9c, 9d, and 9e is deflected the most, followed by the bridge 9e that is deflected the second largest, and the amount of deflection of the bridge 9d is the smallest.

[0050] The rigidity of the outer peripheral portion 9a is lowest in the circumferential direction at the outer peripheral portion of the arc-shaped hole h6 which has the widest bridge spacing, the second lowest at the outer peripheral portion of the arc-shaped hole h4 which has the second widest bridge spacing, and the highest at the outer peripheral portion of the arc-shaped hole h5 which has the narrowest bridge spacing. Therefore, the rigidity of the outer peripheral portion 9a is lowest near the circumferential center of the arc-shaped hole h6, followed by the circumferential center of the arc-shaped hole h4 and the circumferential center of the arc-shaped hole h5, in that order, and when the outer peripheral portion 9a is subjected to the pressure of the reservoir R, the portion with low rigidity in the circumferential direction is largely separated from the suction-side seat portion 8g and deforms in a circumferential undulating manner.

[0051] For this reason, the bridge 9e disposed between the outer peripheral portion of the arc-shaped hole h5, which is the hardest to separate from the suction-side seat portion 8g in the outer peripheral portion 9a, and the outer peripheral portion near the center of the arc-shaped hole h6, which is the easiest to separate, is not only bent but also twisted due to the undulating deformation of the outer peripheral portion 9a, so that a large stress acts on the arc-shaped hole h6 side of the root of the bridge 9e to the inner peripheral portion 9b. Also, the bridge 9d disposed between the outer peripheral portion of the arc-shaped hole h5, which is the hardest to separate from the suction-side seat portion 8g in the outer peripheral portion 9a, and the outer peripheral portion near the center of the arc-shaped hole h4, which is the second easiest to separate, is not only bent but also twisted due to the undulating deformation of the outer peripheral portion 9a, so that the second largest stress acts on the arc-shaped hole h4 side of the root of the bridge 9d to the inner peripheral portion 9b.

[0052] To address this, in the disk 9 of the valve V2 of this embodiment, the size of the R-shape of the corners h4b, h5a on the inner peripheral portion 9b side, which are the fixed ends facing each other in the circumferential direction of the arc-shaped holes h4, h5 having different circumferential lengths, is made larger for the corner h4b of the arc-shaped hole h4 having a longer circumferential length than for the corner h5a of the arc-shaped hole h5 having a shorter circumferential length. In this case, since the corners h4b, h5a are R-shaped, the radius of the R-shape of the corner h4b of the arc-shaped hole h4 is made larger than the radius of the R-shape of the corner h5a of the arc-shaped hole h5, and the width of the arc-shaped hole h4 side of the base of the bridge 9d to the inner peripheral portion 9b is widened to alleviate stress concentration.

[0053] In the disk 9, the size of the R-shape of the corners h5b, h6a on the inner peripheral portion 9b side, which are the fixed ends facing each other in the circumferential direction of the arc-shaped holes h5, h6 having different circumferential lengths, is made larger for the corner h6a of the arc-shaped hole h6 having a longer circumferential length than for the corner h5b of the arc-shaped hole h5 having a shorter circumferential length. In this case, since the corners h5b, h6a are R-shaped, the radius of the R-shape of the corner h6a of the arc-shaped hole h6 is made larger than the radius of the R-shape of the corner h5b of the arc-shaped hole h5, and the width of the arc-shaped hole h6 side of the base of the bridge 9e to the inner peripheral portion 9b is widened to alleviate stress concentration.

[0054] Furthermore, in the disk 9, the size of the R-shape of the corners h6b, h4a on the inner peripheral portion 9b side, which are the fixed ends facing each other in the circumferential direction of the arc-shaped holes h6, h4 having different circumferential lengths, is made larger for the corner h6b of the arc-shaped hole h6 having a longer circumferential length than for the corner h4a of the arc-shaped hole h4 having a shorter circumferential length. In this case, since the corners h6b, h4a are R-shaped, the radius of the R-shape of the corner h6b of the arc-shaped hole h6 is made larger than the radius of the R-shape of the corner h4a of the arc-shaped hole h4, and the width of the arc-shaped hole h6 side of the base of the bridge 9d to the inner peripheral portion 9b is widened to alleviate stress concentration.

[0055] Therefore, the size of the R-shape of the corners h6a, h6b at both corners on the inner periphery 9b side of the arc-shaped hole h6, which has the longest circumferential length, is made equal and the largest, followed by the size of the R-shape of the corners h4a, h4b at both corners on the inner periphery 9b side of the arc-shaped hole h4, which has the second longest circumferential length, and further the size of the R-shape of the corners h5a, h5b at both corners on the inner periphery 9b side of the arc-shaped hole h5, which has the shortest circumferential length, is made the smallest.

[0056] In this way, the rigidity of the outer peripheral portion 9a of the disk 9 decreases as the circumferential length of the arc-shaped holes h4, h5, h6 increases, as the installation spacing of the bridges 9c, 9d, 9e increases and so the bridges 9c, 9d, 9e are subjected to stress due to torsion in addition to stress due to bending when the disk 9 is opened. However, by increasing the size of the R-shape of the corners h4a, h4b, h5a, h5b, h6a, h6b of the arc-shaped holes h4, h5, h6 as the circumferential length of the arc-shaped holes h4, h5, h6 increases, the width of the base of the inner peripheral portion 9b of the bridges 9c, 9d, 9e can be adjusted to alleviate stress.

[0057] The valves V1, V2 and the shock absorber D are configured as described above, and their operation will be described below. First, when the shock absorber D performs an extension operation and the piston 1 moves upward in FIG. 1 relative to the cylinder 20, the liquid in the expansion-side chamber R1, which is compressed by the upward movement of the piston 1 in FIG. 1, bends the expansion-side leaf valve 3 and moves to the compression-side chamber R2 through the expansion-side port 1b. Since the expansion-side leaf valve 3 provides resistance to the flow of liquid from the expansion-side chamber R1 to the compression-side chamber R2, the pressure in the expansion-side chamber R1 increases.

[0058] In addition, as the shock absorber D expands, the liquid equivalent to the volume of the rod 21 retracting from the cylinder 20 pushes open the outer periphery 9a of the disk 9 and moves to the pressure-side chamber R2 through the suction port 8e. Since the disk 9 provides almost no resistance to the flow of liquid passing through the suction port 8e, the pressure in the pressure-side chamber R2 becomes almost equal to the pressure in the reservoir R.

[0059] Therefore, during the extension operation of the shock absorber D, the pressure in the expansion-side chamber R1 rises, and the pressure in the compression-side chamber R2 becomes almost equal to the pressure in the reservoir R, and a difference occurs between the pressure in the expansion-side chamber R1 and the pressure in the compression-side chamber R2, so that the shock absorber D generates a damping force that hinders the extension operation. Note that, during the extension operation of the shock absorber D, as described above, the disk 9 opens, and the volume of the rod 21 that retreats from the cylinder 20 is supplied from the reservoir R to the cylinder 20, thereby compensating for the volume of the rod 21 that retreats from the cylinder 20. Furthermore, when the disk 9 separates the outer periphery 9a from the suction-side seat portion 8g to perform the valve opening operation, the entire circumference of the outer periphery 9a does not separate from the suction-side seat portion 8g at once, but the outer periphery 9a separates from the suction-side seat portion 8g in order from the portion with the lowest rigidity, so that the valve opening operation is smooth and the pressure in the compression-side chamber R2 does not change suddenly, and the generation of abnormal noise and the sudden change in the damping force can be mitigated.

[0060] On the other hand, when the shock absorber D contracts and the piston 1 moves downward in Fig. 1 relative to the cylinder 20, the liquid in the compression-side chamber R2, which is compressed by the downward movement of the piston 1 in Fig. 1, pushes open the disc 2 and moves through the compression-side port 1c to the expanded expansion-side chamber R1. Since the disc 2 provides almost no resistance to the flow of liquid passing through the compression-side port 1c, the pressure in the expansion-side chamber R1 and the pressure in the compression-side chamber R2 become almost equal.

[0061] In addition, as the shock absorber D contracts, the liquid in the cylinder 20 is excessive in proportion to the volume of the rod 21 that penetrates into the cylinder 20, and the liquid pushes open the compression-side leaf valve 10 and moves from the compression-side chamber R2 to the reservoir R through the discharge port 8d. The compression-side leaf valve 10 provides resistance to the flow of liquid from the compression-side chamber R2 to the reservoir R, so that the pressures in the compression-side chamber R2 and the expansion-side chamber R1, which are in communication with each other as the disc 2 opens, rise almost equally. In this way, when the shock absorber D contracts, the liquid in the cylinder 20 in proportion to the volume of the rod 21 that penetrates into the cylinder 20 is discharged to the reservoir R from within the cylinder 20, thereby compensating for the volume of the rod 21 that penetrates into the cylinder 20.

[0062] The shock absorber D of this embodiment is a single-rod type shock absorber in which the rod 21 is inserted only into the expansion-side chamber R1, and the pressure-receiving area of ​​the piston 1 that receives the pressure in the contraction-side chamber R2 is larger than the pressure-receiving area that receives the pressure in the expansion-side chamber R1 by the cross-sectional area of ​​the rod 21, so that when the pressures in the contraction-side chamber R2 and the expansion-side chamber R1 are substantially equal, the piston 1 receives a force in a direction that pushes the rod 21 out of the cylinder 20. Therefore, when the shock absorber D performs a contraction operation, it generates a damping force in a direction that pushes the rod 21 out of the cylinder 20, thereby hindering the contraction operation.

[0063] Furthermore, when the disk 2 is opened by lifting the outer peripheral portion 2a off the compression-side seat portion 1e, the entire circumference of the outer peripheral portion 2a does not move away from the compression-side seat portion 1e all at once, but the outer peripheral portion 2a moves away in sequence starting from the portion with the lowest rigidity. This makes the valve-opening operation smoother and prevents a sudden change in pressure in the compression-side chamber R2 and the expansion-side chamber R1, thereby reducing the generation of abnormal noise and a sudden change in damping force.

[0064] As described above, the valve V1 of this embodiment comprises a piston (valve seat member) 1 having a compression side port (port) 1c, and a disk 2 which is annular, has an inner circumference as a fixed end and an outer circumference as a free end, and is allowed to flex on the free end side, and is stacked on the piston (valve seat member) 1. The disk 2 has three or more arc-shaped holes h1, h2, h3 which are arranged intermittently in the circumferential direction on the same circumference and have some or all different circumferential lengths, and the size of the R-shape of the corners h1b, h2a on the fixed end sides which face each other in the circumferential direction of the arc-shaped holes h1, h2 with different circumferential lengths and the size of the R-shape of the corners h2b, h3a are larger for the arc-shaped holes h1, h3 which have a longer circumferential length than for the arc-shaped hole h2 which has a shorter circumferential length.

[0065] Moreover, the valve V2 of this embodiment includes a valve case (valve seat member) 8 having a suction port (port) 8e, and a disk 9 which is annular, with its inner circumference as a fixed end and its outer circumference as a free end, allowing deflection on the free end side, and is stacked on the valve case (valve seat member) 8. The disk 9 has three or more arc-shaped holes h4, h5, h6 which are arranged intermittently in the circumferential direction on the same circumference and some or all of which have different circumferential lengths, and the size of the R-shape of the corners h4b, h5a between the fixed ends of the arc-shaped holes h4, h5 which have different circumferential lengths, the corners h5b, h6a between the arc-shaped holes h5, h6, and the corners h6b, h4a between the arc-shaped holes h6, h4 which have different circumferential lengths is larger for the arc-shaped hole with a longer circumferential length than for the arc-shaped hole with a shorter circumferential length.

[0066] In the valves V1, V2 configured in this manner, the circumferential lengths of some of the arc-shaped holes h1, h2, h3 in the disk 2 are different, and the circumferential lengths of all of the arc-shaped holes h4, h5, h6 in the disk 9 are different, so that it is possible to provide a difference in the circumferential rigidity of the outer periphery 2a, 9a according to the circumferential lengths of the arc-shaped holes h1, h2, h3, h4, h5, h6. Therefore, the outer periphery 2a, 9a of the disks 2, 9 does not open all at once, but opens in order from the parts with the lowest rigidity, thereby realizing a smooth valve opening operation. In the valves V1 and V2, the size of the R-shape between the corners of the fixed ends of the arc-shaped holes that are different in circumferential length is larger in the arc-shaped holes that are longer in circumferential length than in the arc-shaped holes that are shorter in circumferential length, so the width of the base of the bridges 2c, 2d, 2e, 9c, 9d, 9e to the inner periphery 2b, 9b becomes wider according to the circumferential lengths of the adjacent arc-shaped holes h1, h2, h3, h4, h5, h6. Therefore, even if the bridges 2c, 2d, 2e, 9c, 9d, 9e arranged between the arc-shaped holes that are different in circumferential length are subjected to torsion during the opening operation of the disks 2 and 9 due to the non-uniform circumferential lengths of the arc-shaped holes h1, h2, h3, h4, h5, h6, the stress of the bridges 2c, 2d, 2e, 9c, 9d, 9e can be relaxed. In addition, the width of the base of the bridges 2c, 2d, 2e, 9c, 9d, 9e to the inner periphery 2b, 9b is not uniformly widened, but the size of the R-shape of the corners facing the longer arc-shaped hole on both circumferential sides of one bridge is made larger than the R-shape of the corners facing the shorter arc-shaped hole, so that the width of the base of the bridges 2c, 2d, 2e, 9c, 9d, 9e is widened, so that the entire circumference of the outer periphery 2a, 9a of the disks 2, 9 does not become difficult to open uniformly, and the smooth valve opening operation caused by the uneven bridge spacing is not hindered. As described above, the valves V1, V2 of this embodiment are less likely to deteriorate while smoothing the valve opening operation.

[0067] In the valve V2 of this embodiment, the corners h4a, h4b, h5a, h5b, h6a, and h6b on the inner periphery 9b side, which is the fixed end side of the arc-shaped holes h4, h5, and h6, are larger as the circumferential length increases. With the valve V2 configured in this way, when the disk 9 is opened, the bridges 9c, 9d, and 9e are subjected to stress due to torsion in addition to stress due to bending. However, by making the corners h4a, h4b, h5a, h5b, h6a, and h6b of the arc-shaped holes h4, h5, and h6 larger as the circumferential length of the arc-shaped holes h4, h5, and h6 increases, the width of the roots of the inner periphery 9b of the bridges 9c, 9d, and 9e can be made appropriate, and the stress can be efficiently alleviated.

[0068] In the above description, the corners h1a, h1b, h2a, h2b, h3a, h3b, h4a, h4b, h5a, h5b, h6a, and h6b are R-shaped, but they may be C-shaped. In the case of a C-shape, the length of one side of the triangle forming the C-shape is set as the size of the C-shape.

[0069] Furthermore, as described above, the disks 2, 9 are configured as so-called outward opening, with the inner circumference as a fixed end and the outer circumference as a free end, and the ports opened and closed at the outer circumference portions 2a, 9a. However, the disks 2, 9 may also be configured as so-called inward opening, with the outer circumference side as a fixed end and the inner circumference side as a free end, and the ports opened and closed at the inner circumference portions 2b, 9b. In that case, the size of the R-shape or C-shape between the corners on the outer circumference sides 2a, 9a that face each other in the circumferential direction between the arc-shaped holes h1, h2, h3, h4, h5, h6 that have different circumferential lengths can be made larger for the arc-shaped holes with a longer circumferential length than for the arc-shaped holes with a shorter circumferential length.

[0070] Furthermore, in the above description, three arc-shaped holes h1, h2, h3, h4, h5, and h6 are provided on each of the disks 2 and 9, but as long as there are a plurality of holes, two or more, and four or more holes may be provided.

[0071] The shock absorber D of this embodiment includes a cylinder 20, a rod 21 inserted into the cylinder 20 so as to be axially movable, a piston 1 connected to the tip of the rod 21 and inserted into the cylinder 20 so as to be axially movable, dividing the inside of the cylinder 20 into an expansion-side chamber R1 and a compression-side chamber R2, and a valve V1, the piston 1 being a valve seat member and the valve V1 being stacked on the expansion-side chamber side of the piston 1. In the shock absorber D configured in this manner, the valve V1 is used as a check valve that opens when the shock absorber D is contracting, which can realize a smooth valve opening operation and can reduce the stress acting on the disc 2 to suppress deterioration, thereby reducing a sudden change in the damping force when the shock absorber D is contracting.

[0072] Further, the shock absorber D of this embodiment includes a cylinder 20, a rod 21 inserted into the cylinder 20 so as to be axially movable, a piston 1 connected to the tip of the rod 21 and inserted into the cylinder 20 so as to be axially movable, dividing the inside of the cylinder 20 into an expansion-side chamber R1 and a compression-side chamber R2, a valve case 8 provided at the end of the cylinder 20 to divide the compression-side chamber R2 and a reservoir R formed outside the cylinder 20, and a valve V2, the valve case 8 being a valve seat member, and the valve V2 being stacked on the compression-side chamber side of the valve case 8. In the shock absorber D configured in this manner, the valve V2 is used as a check valve that opens when the shock absorber D is extended, and a smooth valve opening operation can be realized, and the stress acting on the disk 9 can be relaxed to suppress deterioration, and a sudden change in the damping force during the extension operation of the shock absorber D can be mitigated.

[0073] In the above description, the disks 2, 9 of the valves V1, V2 of the present embodiment directly seat and separate from the valve seat members 1, 8 to open and close the ports 1c, 8e. However, the disks 2, 9 may be stacked on the back surface of an annular leaf valve that directly seat and separate from the valve seat members 1, 8 to open and close the ports 1c, 8e. In this case, the disks 2, 9 have a difference in rigidity in the circumferential direction, so that the leaf valve and the disks 2, 9 as a whole are used as a valve, and the valve is provided with a difference in rigidity in the circumferential direction to smooth the valve opening operation. In addition, the valves V1, V2 are used as check valves in the shock absorber D, but they may be used as damping valves that actively provide resistance to the flow of liquid passing through the ports by using a spring that biases them from the back surface side or by being stacked on the leaf valve. When a damping valve is formed by stacking a disk on the side opposite the valve seat member of a leaf valve that does not have a hole, the valves V1, V2 can also be used as expansion side leaf valves or compression side leaf valves in the shock absorber D.

[0074] Furthermore, as described above, the seat portions 1e, 8g of the piston 1 and the valve case 8 are both annular seat portions, but the seat portions 1e, 8g may also be petal-shaped seat portions that independently surround each of the ports 1c, 8e.

[0075] Although the preferred embodiment of the present invention has been described in detail above, modifications, variations and changes can be made without departing from the scope of the appended claims. [Explanation of symbols]

[0076] 1···Piston (valve seat member), 1c···Compression side port (port), 2,9···Disk, D···Shock absorber, h1,h2,h3,h4,h5,h6···Circular hole, h1a,h1b,h2a,h2b,h3a,h3b,h4a,h4b,h5a,h5b,h6a,h6b···Corner portion, V1,V2···Valve, R···Reservoir, R1···Extension side chamber, R2···Compression side chamber

Claims

1. a valve seat member having a port; a disk having an annular shape, one of an outer periphery and an inner periphery being a fixed end and the other of the outer periphery and the inner periphery being a free end, the free end being allowed to deform, and the disk being laminated on the valve seat member; the disk has two or more arc-shaped holes provided intermittently in the circumferential direction on the same circumference, some or all of which have different circumferential lengths; The size of the R-shape or C-shape between the corners on the fixed end sides that face each other in the circumferential direction of the arc-shaped holes having different circumferential lengths is larger for the arc-shaped holes having a longer circumferential length than for the arc-shaped holes having a shorter circumferential length. A valve characterized by:

2. The size of the R-shape or C-shape on the fixed end side of the circular arc-shaped hole increases as the circumferential length increases.

2. The valve according to claim 1 .

3. A cylinder; A rod that is inserted into the cylinder so as to be movable in the axial direction; a piston connected to a tip end of the rod and inserted into the cylinder so as to be axially movable, dividing the inside of the cylinder into an expansion-side chamber and a compression-side chamber; The valve according to claim 1 or 2, The piston is the valve seat member, The valve is stacked on the extension side of the piston. A shock absorber characterized by:

4. A cylinder; A rod that is inserted into the cylinder so as to be movable in the axial direction; a piston connected to a tip end of the rod and inserted into the cylinder so as to be axially movable, dividing the inside of the cylinder into an expansion-side chamber and a compression-side chamber; a valve case provided at an end of the cylinder and dividing the pressure-side chamber from a reservoir formed outside the cylinder; The valve according to claim 1 or 2, The valve case serves as the valve seat member, The valve is stacked on the pressure side chamber side of the valve case. A shock absorber characterized by:

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