JP5826595B2 - Hydraulic shock absorber valve structure - Google Patents

Description

  The present invention relates to a valve structure of a hydraulic shock absorber.

  The hydraulic shock absorber divides the first and second oil chambers by a piston inserted into the piston rod, and provides the piston with a flow path that allows the first oil chamber and the second oil chamber to communicate with each other. A damping valve is provided on one end face of the piston through which this flow path opens.

  In the conventional hydraulic shock absorber valve structure, the damping valve is fastened against the pressure-receiving surface (end face) where the piston passage is open, and the damping valve is bent by the pressure of the passage to Open and close. An expensive high-strength metal material is adopted as a constituent material of the piston on which the fastening force acts, and the pressure receiving surface is processed with high accuracy by sintering or cutting with high processing accuracy.

  On the other hand, in order to reduce the cost of the piston, as described in Patent Document 1, the inner peripheral portion (boss portion) that is inserted into the piston rod of the piston and receives the fastening force is reinforced with a metal material, The thing which comprises the outer peripheral part in which this is provided with an inexpensive resin material is proposed.

JP2004-293594

  In the valve structure of the hydraulic shock absorber described in Patent Literature 1, when the hydraulic shock absorber is heated to a high temperature by use, the thermal expansion of the resin material is large, and the damping provided to open and close the flow path provided in the resin material A load resulting from thermal expansion of the resin material is applied to the valve. For this reason, there exists a possibility that damping force may become unstable.

  An object of the present invention is to constitute a piston of a hydraulic shock absorber only with a resin material that is inexpensive and easy to mold.

In the invention according to claim 1, the first and second oil chambers are partitioned by the piston inserted into the piston rod, and the flow path that enables communication between the first oil chamber and the second oil chamber is provided in the piston. In the valve structure of the hydraulic shock absorber, in which a damping valve is provided on one end face of the piston that is open to the flow path, provided on the other end face side of the piston, and presses one end face of the piston against the damping valve. The piston moves in the axial direction of the piston rod in accordance with the expansion and contraction of the elastic body, so that one end face of the piston can be brought into contact with and separated from the damping valve, and the damping valve is attached to the piston rod. A valve seat that is held on the piston rod by a valve stopper to be fastened, has a smaller diameter than the damping valve, and is in contact with the back surface of the damping valve is sandwiched between the damping valve and the valve stopper. None of smaller diameter than the damping valve, the valve support in contact with the surface facing to the piston of the damping valve, in which was set to be fixed to the piston rod.

According to a second aspect of the present invention, in the first aspect of the present invention, a piston ring is loaded on the outer periphery of the piston .

According to a third aspect of the present invention, in the first or second aspect of the present invention, the valve support further includes an annular fixing portion extending along the outer periphery of the piston rod, and a valve extending radially from a plurality of locations on the outer periphery of the annular fixing portion. And a deformed hole portion that can be fitted into the annular fixing portion of the valve support and the valve support portion on the inner diameter of the piston rod that is inserted into the piston rod .

The invention according to claim 4 is the invention according to claim 3 , wherein the moving stroke of the piston is shorter than the fitting length between the irregularly shaped hole portion of the piston and the annular fixing portion and the valve support portion of the valve support. It is a thing.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects , two sets of valve units each including the piston, the damping valve, and the elastic body are provided on the piston rod, The pair is arranged back to back .

The invention according to a sixth aspect is the invention according to any one of the first to fifth aspects, wherein the piston is made of only a resin material .

(Claims 1, 2, 6 )
(a) Since the piston contacts and separates from the damping valve according to the expansion and contraction of the elastic body and does not receive the force to fasten the damping valve, it only needs to withstand the load caused by the generation of the damping force, and is expensive. There is no need to use a strong metal material. Therefore, a rougher processing method and a weaker material can be used for the piston if the processing accuracy of the end face to which the damping valve is in close contact can be obtained.

  That is, the piston can be made of only an inexpensive resin material, for example, and can be manufactured by injection molding capable of molding a complicated shape with high accuracy, and the damping force does not become unstable even when thermally expanded. Further, by providing a backlash in the center hole inserted into the piston rod of the piston, an eccentric error between the piston rod and the cylinder can be tolerated to some extent, and slidability of the piston can also be expected.

(b) When the piston ring is loaded on the outer periphery of the piston, the sealing performance with the cylinder can be ensured without requiring the outer periphery accuracy of the piston itself.

  By providing a gap between the piston and the piston ring or making the piston ring made of an elastic material, even if the piston is thermally expanded in the radial direction, the sliding resistance between the piston and the cylinder does not increase.

(c) When the pressure of the oil chamber on the side opposite to the side where the damping valve of the piston is provided increases and the oil flows in the positive direction, if the diameter of the valve seat is smaller than the diameter of the flow path with respect to the central axis of the piston, The action of opening the damping valve is also caused by the preset load of the elastic body behind the piston, and the low-speed damping force is reduced. Although this characteristic also becomes a restriction on the setting of damping force, it can be used as a new setting method by making good use of this characteristic.

(d) When the pressure of the oil chamber on the side where the damping valve of the piston is installed increases and the oil flows in the opposite direction, the piston moves in a direction away from the damping valve by compressing the elastic body. A gap through which oil flows is generated between them, and a damping force is generated. At this time, the pressure in the oil chamber also acts on the damping valve, and the above-described gap between the damping valve and the piston is not sufficiently opened due to the reverse warping of the damping valve, resulting in excessive increase in damping force and damage to the damping valve. There is a fear. This reverse warping can be avoided by making the rigidity of the elastic body sufficiently low relative to the rigidity of the damping valve, but can also be avoided by carrying the damping valve by a valve support that contacts the surface of the damping valve facing the piston. .

(Claim 3 )
(e) The valve support of the above (d) has an annular fixing portion along the outer periphery of the piston rod, and a valve support portion extending radially from a plurality of locations on the outer periphery of the annular fixing portion. The inner diameter to be inserted has a deformed hole portion that can be fitted into the annular fixing portion and the valve support portion of the valve support. The valve support portion of the valve support increases the fulcrum radius with respect to the damping valve, and effectively avoids the above-described reverse warping.

  At this time, the valve support part of the valve support is provided only at a plurality of locations on the outer periphery of the annular fixed part, and the valve support part of the valve support is intermittently arranged in the circumferential direction of the damping valve, so that it is provided all around the damping valve. Compared to the above, it effectively reduces the bearing range of the damping valve by the valve support. This reduces the bending resistance of the damping valve when the oil flows in the positive direction, and avoids an unexpectedly high high-speed damping force.

  Therefore, the rigidity of the damping valve is not increased, and reverse warping can be prevented stably even when the damping valve is relatively low.

(Claim 4 )
(f) In the above (e), the moving stroke of the piston is made shorter than the fitting length between the irregularly shaped hole portion of the piston and the annular fixing portion and the valve support portion of the valve support. Thereby, when a piston moves according to expansion-contraction of an elastic body, the valve support part of a valve support continues fitting to the irregularly shaped hole part of a piston. Even if the piston and the valve support are not locked against each other, they will continue to be fitted in their axial directions.

(Claim 5 )
(g) Two sets of valve units composed of a piston, a damping valve, and an elastic body are provided on the piston rod, and each set of valve units is arranged back to back. Thereby, the damping force of both the compression side stroke and the extension side stroke can be generated by the bending resistance of the damping valve. Accordingly, the damping force characteristic can be increased.

1 is a cross-sectional view showing a hydraulic shock absorber of Reference Example 1. FIG. FIG. 2 is an enlarged cross-sectional view of the main part of FIG. FIG. 3 is a cross-sectional view showing the state of damping force generation in the extension side stroke and the compression side stroke. FIG. 4 is an exploded perspective view of FIG. FIG. 5 is an enlarged cross-sectional view of a main part of the hydraulic shock absorber according to the first embodiment. 6 is a cross-sectional view showing a cross section different from FIG. FIG. 7 is a perspective view showing the piston and the valve support. FIG. 8 is an exploded perspective view of FIG. FIG. 9 is a cross-sectional view showing a hydraulic shock absorber according to the second embodiment. FIG. 10 is a cross-sectional view showing the state of generation of damping force in the extension side stroke. FIG. 11 is a cross-sectional view showing the state of generation of damping force in the compression side stroke.

( Reference Example 1) (FIGS. 1 to 4)
As shown in FIG. 1, the hydraulic shock absorber 10 has a piston rod 12 inserted into a cylinder 11 and a suspension spring (not shown) interposed between the cylinder 11 and the piston rod 12. The cylinder 11 includes a vehicle body side mounting member 14, and the piston rod 12 includes an axle side mounting member (not shown).

  The cylinder 11 is provided with a rod guide 20 through which the piston rod 12 penetrates in a fluid-tight manner. The rod guide 20 allows the piston rod 12 to slide in a liquid-tight manner on an inner diameter portion including an oil seal 21 and a bush 22. The cylinder 11 includes a washer 23 and a rebound rubber 24 inside the rod guide 20.

  The hydraulic shock absorber 10 has a piston valve device 30. The hydraulic shock absorber 10 dampens the expansion and contraction vibration of the cylinder 11 and the piston rod 12 due to the absorption of the impact force by the suspension spring by the damping force generated by the piston valve device 30.

  As shown in FIGS. 2 and 4, the piston valve device 30 has a set of valve units 30 </ b> A inserted into the tip of the piston rod 12 inserted into the cylinder 11 and held by a nut 37. The valve unit 30A includes a spring receiver 31, a compression coil spring 32 as an elastic body, a piston 33 made of only a resin material, a damping valve 34 in which a plurality of bending plates are stacked, a valve seat 35, and a valve stopper 36. The spring receiver 31 is caulked by a retaining ring 31R that is engaged with an intermediate portion of the piston rod 12. The spring 32 and the piston 33 are inserted around the piston rod 12. The damping valve 34, the valve seat 35, and the valve stopper 36 are loaded into the tip small diameter step portion of the piston rod 12, and are fastened to the small diameter step portion by the nut 37.

  The piston valve device 30 liquid-tightly slides inside the cylinder 11 via a piston ring 33R loaded in the outer peripheral groove portion of the piston 33, and the piston-side oil chamber 37A (the first piston chamber 12A in which the piston rod 12 is not accommodated). 1 oil chamber) and a rod side oil chamber 37B (second oil chamber) in which the piston rod 12 is accommodated. The piston 33 is provided with a flow path 38 that allows the oil chamber 37A and the oil chamber 37B to communicate with each other, and a damping valve 34 is provided on the end surface on the piston side oil chamber 37A side (one side) where the flow path 38 opens.

  The piston valve device 30 includes the piston 33 made of only the resin material as described above, and the piston-side oil chamber of the piston 33 is provided by the spring 32 provided on the rod-side oil chamber 37B side (the other end) side of the piston 33. The end face on the 37A side (one side) is pressed against the damping valve 34. The piston 33 moves in the axial direction of the piston rod 12 according to the expansion and contraction of the spring 32 in the stroke of the pressure side and the extension side receiving the pressure of the piston side oil chamber 37A and the pressure of the rod side oil chamber 37B. The end surface on the piston side oil chamber 37A side (one side) is brought into contact with and separated from the damping valve 34 as shown in FIGS.

  The piston valve device 30 holds the damping valve 34 and the valve seat 35 on the piston rod 12 by a valve stopper 36 fastened to the piston rod 12. The valve seat 35 sandwiched between the damping valve 34 and the valve stopper 36 has a smaller diameter than the damping valve 34 and contacts the back surface of the damping valve 34. The valve seat 35 may have a larger diameter than the damping valve 34 in accordance with the damping characteristics of the valve unit 30A.

  The hydraulic shock absorber 10 includes a partition member 41 that partitions the volume compensation chamber 40 with respect to the piston-side oil chamber 37 </ b> A of the cylinder 11. The partition member 41 is fixedly held by a protrusion 42 provided on the inner diameter of the cylinder 11. The volume compensation chamber 40 includes an oil reservoir chamber 40A and a gas chamber 40B defined by the oil reservoir chamber 40A and the free piston 43, and an orifice 41A communicating the piston-side oil chamber 37A and the oil reservoir chamber 40A is a partition wall. It is drilled on the central axis of the member 41. The hydraulic shock absorber 10 supplies and discharges the oil in the piston-side oil chamber 37 </ b> A to the oil reservoir chamber 40 </ b> A of the volume compensation chamber 40 in order to compensate for the volume of the piston rod 12 entering / exiting the cylinder 11 during compression and extension. As described above, the compression side and the extension side oil flows are passed through the same orifice 41A, and the compression force and the extension side damping force are generated based on the squeezing resistance imparted to the oil by the orifice 41A.

Therefore, the hydraulic shock absorber 10 performs a damping action as follows.
(Extension side stroke) (FIG. 3 (A))
When the pressure in the rod side oil chamber 37B increases during the extension side stroke, the damping valve 34 bends. At this time, the bending curve of the damping valve 34 is curved, and the inclination of the bent damping valve 34 increases toward the outer periphery. On the other hand, the piston 33 is pressed against the damping valve 34 by being pressed by the pressure in the rod side oil chamber 37B, but does not follow the bending curve of the damping valve 34 if the piston 33 has sufficient rigidity. As a result, a gap is formed between the end face of the piston 33 on the outer peripheral side of the damping valve 34, and this gap passes through the flow path 38 of the piston 33 from the rod side oil chamber 37B to the piston side oil chamber 37A. A flow path resistance is exerted on the flow (arrow in FIG. 3A), and a damping force is generated. This damping characteristic is determined by the rigidity of the damping valve 34, the diameter of the valve seat 35, the shape of the flow path 38 provided in the piston 33, the radial position of the flow path 38 with respect to the central axis of the piston 33, and the like. Can be adjusted.

  At this time, if the radius of the valve seat 35 is made smaller than the radial position of the flow path 38 with respect to the central axis of the piston 33, the action of opening the damping valve 34 also occurs due to the preset load of the spring 32 behind the piston 33. Damping force decreases.

(Pressure side stroke) (Fig. 3 (B))
When the pressure in the piston-side oil chamber 37 </ b> A increases during the pressure-side stroke, the piston 33 moves away from the damping valve 34. This creates a gap between the piston 33 and the damping valve 34, and this gap flows from the piston-side oil chamber 37A through the flow path 38 of the piston 33 toward the rod-side oil chamber 37B (FIG. 3B). The flow path resistance is exerted on the arrow) and a damping force is generated. In this damping characteristic, the spring force of the spring 32 is a dominant factor.

  At this time, the pressure in the piston-side oil chamber 37A also acts on the damping valve 34. Due to the reverse warping of the damping valve 34, the gap between the damping valve 34 and the piston 33 is not sufficiently opened. 34 may be damaged. This reverse warping can be avoided by making the rigidity of the spring 32 sufficiently lower than the rigidity of the damping valve 34.

Therefore, according to this reference example, the following operational effects can be obtained.
(a) Since the piston 33 contacts and separates from the damping valve 34 according to the expansion and contraction of the spring 32 and does not receive a force for fastening the damping valve 34, it is sufficient to withstand only a load caused by the generation of the damping force. There is no need to use expensive high-strength metal materials. Therefore, if the processing accuracy of the end surface where the damping valve 34 is in close contact with the piston 33 can be obtained, a rougher processing method and a weak material can be employed.

  That is, the piston 33 can be made of only an inexpensive resin material and can be manufactured by injection molding capable of forming a complicated shape with high accuracy, and the damping force does not become unstable even when thermally expanded. Further, by providing a backlash in the center hole inserted into the piston rod 12 of the piston 33, an eccentric error between the piston rod 12 and the cylinder 11 can be allowed to some extent, and slidability of the piston 33 can also be expected.

  (b) When the piston ring 33R is loaded on the outer periphery of the piston 33, the sealing performance with the cylinder 11 can be secured without requiring the outer periphery accuracy of the piston 33 itself.

  By providing a gap between the piston 33 and the piston ring 33R or making the piston ring 33R of an elastic material, even if the piston 33 is thermally expanded in the radial direction, the sliding resistance between the piston 33 and the cylinder 11 Does not increase.

  (c) When the pressure of the oil chamber on the side opposite to the side where the damping valve 34 of the piston 33 is provided rises and the oil flows in the positive direction, the valve seat 35 is larger than the diameter of the flow path 38 with respect to the central axis of the piston 33. When the diameter is reduced, an action of opening the damping valve 34 is generated even by a preset load of the spring 32 behind the piston 33, and the low-speed damping force is reduced. Although this characteristic also becomes a restriction on the setting of damping force, it can be used as a new setting method by making good use of this characteristic.

Example 1 (FIGS. 5 to 8)
Example 1 Reference Example 1 differs in the following points.
That is, in the valve unit 30A, when the damping valve 34 is fastened and held at the small diameter step portion of the piston rod 12 by the valve stopper 36 fastened to the piston rod 12, the front surface of the damping valve 34 (surface facing the piston 33). A valve support 39 in contact with the piston rod 12 is fixed to the small-diameter step portion of the piston rod 12 as shown in FIGS. The valve support 39 has a smaller diameter than the damping valve 34.

  At this time, as shown in FIG. 7, the valve support 39 extends radially from the annular fixing portion 39A inserted into the piston rod 12 along the outer periphery of the piston rod 12 and from a plurality of locations on the outer periphery of the annular fixing portion 39A. And a valve support portion 39B. Further, as shown in FIG. 7, the piston 33 has a deformed hole portion 33 </ b> A that can be fitted to the annular fixing portion 39 </ b> A of the valve support 39 and the valve support portion 39 </ b> B on the inner diameter inserted into the piston rod 12.

  Further, the movement stroke St of the piston 33 in the axial direction of the piston rod 12 described above is as shown in FIG. 5 between the deformed hole 33A of the piston 33, the annular fixing portion 39A of the valve support 39 and the valve support 39B. It is set shorter than the fitting length L. 5 and 6 show the stroke end where the piston 33 is moved away from the damping valve 34 by the pressure in the piston side oil chamber 37A in the pressure side stroke. 5 shows a cross section passing through a gap between adjacent valve support portions 39B, and FIG. 6 shows a cross section obtained by cutting the entire length of the valve support portion 39B.

Therefore, according to the present Example, in addition to the effect of (a)-(c) of the reference example 1, there exist the following effects.
(d) When the pressure of the piston-side oil chamber 37A on the side where the damping valve 34 of the piston 33 is provided increases, the piston 33 compresses the spring 32 and moves away from the damping valve 34 when the oil flows in the opposite direction. It moves and creates a gap through which oil flows between the damping valve 34 and the piston 33, and a damping force is generated. At this time, the pressure in the piston-side oil chamber 37A described above also acts on the damping valve 34, and the above-described gap between the damping valve 34 and the piston 33 is not sufficiently opened due to the reverse warping of the damping valve 34, and the damping force is excessively increased. Otherwise, the damping valve 34 may be damaged. This reverse warping can be avoided by making the rigidity of the spring 32 sufficiently lower than the rigidity of the damping valve 34, but it can also be avoided by carrying the damping valve 34 by the valve support 39 in contact with the front face of the damping valve 34. it can.

  (e) The valve support 39 of the above (d) has an annular fixing portion 39A along the outer periphery of the piston rod 12, and a valve support portion 39B extending radially from a plurality of locations on the outer periphery of the annular fixing portion 39A. The inner diameter of the piston 33 inserted into the piston rod 12 has an irregularly shaped hole 33A that can be fitted into the annular fixing portion 39A of the valve support 39 and the valve support portion 39B. The valve support 39B of the valve support 39 has a large fulcrum radius with respect to the damping valve 34, and effectively avoids the above-described reverse warping.

  At this time, the valve support 39B of the valve support 39 is provided only at a plurality of locations on the outer periphery of the annular fixing portion 39A, and the valve support 39B of the valve support 39 is intermittently disposed in the circumferential direction of the damping valve 34, thereby reducing the damping valve 34. Compared with the case where it is provided on the entire circumference, the holding range of the damping valve 34 by the valve support 39 is effectively reduced. This reduces the bending resistance of the damping valve 34 when the oil flows in the positive direction, and avoids an unexpectedly high high-speed damping force.

  Therefore, the rigidity of the damping valve 34 is not increased, and even when the damping valve 34 is relatively low, reverse warping can be stably prevented.

  (f) In the above (e), the moving stroke St of the piston 33 is shorter than the fitting length L between the deformed hole portion 33A of the piston 33 and the annular fixing portion 39A and the valve support portion 39B of the valve support 39. I made it. Thereby, when the piston 33 moves according to the expansion and contraction of the spring 32, the valve support portion 39 </ b> B of the valve support 39 continues to be fitted into the deformed hole portion 33 </ b> A of the piston 33. Even if the piston 33 and the valve support 39 are not prevented from rotating together, they will continue to fit in their axial directions.

Example 2 (FIGS. 9 to 11)
Example 2 Reference Example 1 differs, as shown in FIG. 9, two sets of the valve unit 30A in the distal end of the piston rod 12, and 30B is provided, and disposed the valve units 30A, 30B set the back to back with each other There is.

One valve unit 30A is the valve unit 30A of the first reference example, and includes a spring receiver 31, a spring 32, a piston 33, a damping valve 34, and a valve seat that are caulked by a retaining ring 31R engaged with an intermediate portion of the piston rod 12. 35 and a valve stopper 36. The other valve unit 30B is composed of the same components as the valve unit 30A, and includes a spring receiver 31, a spring 32, a piston 33, a damping valve 34, a valve seat 35, and a valve stopper 36 that are screwed onto the tip of the piston rod 12. Thus, the valve stopper 36 of the valve unit 30A and the valve stopper 36 of the valve unit 30B are made common.

  In the extension side stroke, as shown in FIG. 10, the damping valve 34 of the valve unit 30 </ b> A bends due to the pressure in the rod side oil chamber 37 </ b> B, and the piston 33 of the valve unit 30 </ b> B moves away from the damping valve 34. As a result, the oil in the rod side oil chamber 37B flows as shown by the arrow in FIG. 10 and passes through the gap formed between the flow path 38 of the piston 33 and the end face of the piston 33 in the valve unit 30A. At this time, a damping force is generated by the flow path resistance of the gap. The oil exiting from the damping valve 34 of the valve unit 30A flows into the piston-side oil chamber 37A through the flow path 38 of the piston 33 in the valve unit 30B.

  In the pressure side stroke, as shown in FIG. 11, the damping valve 34 of the valve unit 30 </ b> B bends due to the pressure in the piston side oil chamber 37 </ b> A, and the piston 33 of the valve unit 30 </ b> A moves away from the damping valve 34. As a result, the oil in the piston-side oil chamber 37A flows as indicated by the arrow in FIG. 11 and passes through the gap formed between the flow path 38 of the piston 33 and the end face of the piston 33 in the valve unit 30B. At this time, a damping force is generated by the flow path resistance of the gap. Oil from the damping valve 34 of the valve unit 30B flows into the rod-side oil chamber 37B through the flow path 38 of the piston 33 in the valve unit 30A.

  Therefore, according to the present embodiment, the damping force of both the compression side stroke and the extension side stroke can be generated by the respective bending resistances of the damping valve 34 of the valve unit 30A and the damping valve 34 of the valve unit 30B. Accordingly, the damping force characteristic can be increased.

Note that the valve support 39 provided in the valve unit 30A of the first embodiment can also be adopted in the valve units 30A and 30B of the hydraulic shock absorber 10 of the second embodiment.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention. For example, the valve structure of the present invention can be applied not only to a piston valve device but also to a base valve device fixedly disposed on the bottom side of a cylinder of a hydraulic shock absorber.

  The valve structure of the present invention may be provided with a damping force adjusting means such as a damping force adjusting needle in a bypass passage that bypasses the piston.

  Further, the valve support employed in the valve structure of the present invention may be formed integrally with the piston rod itself or formed integrally with a piston bolt that is connected to the piston rod and into which the piston is inserted.

  Moreover, as a constituent material of the piston employed in the valve structure of the present invention, a light and weak material can be employed, and not only a resin material but also aluminum, magnesium, ceramic, or the like can be employed.

According to the present invention , the piston of the hydraulic shock absorber can be configured only with an inexpensive and easily moldable resin material.

DESCRIPTION OF SYMBOLS 10 Hydraulic buffer 11 Cylinder 12 Piston rod 30 Piston valve apparatus 30A, 30B Valve unit 32 Spring (elastic body)
33 Piston 33A Deformed hole 33R Piston ring 34 Damping valve 35 Valve seat 36 Valve stopper 37A Piston side oil chamber (first oil chamber)
37B Rod side oil chamber (second oil chamber)
39 Valve support 39A Annular fixing part 39B Valve support part

Claims (6)

The first and second oil chambers are partitioned by a piston inserted into the piston rod,
In the valve structure of the hydraulic shock absorber provided with a flow path that enables communication between the first oil chamber and the second oil chamber in the piston, and provided with a damping valve on one end face of the piston that opens the flow path,
An elastic body provided on the other end face side of the piston and pressing one end face of the piston against the damping valve;
The piston moves in the axial direction of the piston rod according to the expansion and contraction of the elastic body, and one end surface of the piston can be brought into contact with and separated from the damping valve ,
The damping valve is held on the piston rod by a valve stopper fastened to the piston rod;
A valve seat that has a smaller diameter than the damping valve and is in contact with the back surface of the damping valve is sandwiched between the damping valve and the valve stopper,
A valve structure for a hydraulic shock absorber, characterized in that a valve support having a smaller diameter than the damping valve and contacting a surface of the damping valve facing the piston is fixed to a piston rod . The valve structure of the hydraulic shock absorber according to claim 1 , wherein a piston ring is loaded on an outer periphery of the piston. The valve support has an annular fixing portion along the outer periphery of the piston rod, and a valve support portion extending radially from a plurality of locations on the outer periphery of the annular fixing portion,
The valve structure for a hydraulic shock absorber according to claim 1 or 2 , wherein the inner diameter inserted into the piston rod of the piston has a deformed hole portion that can be fitted to the annular fixing portion and the valve support portion of the valve support. The valve structure of the hydraulic shock absorber according to claim 3 , wherein a moving stroke of the piston is shorter than a fitting length between the irregularly shaped hole portion of the piston and the annular fixing portion and the valve support portion of the valve support. Said piston and provided 2 sets of pairs of valve unit comprising a damping valve and the elastic member on the piston rod, the hydraulic shock according to any one of claims 1 to 4, a pair of the valve units formed by arranging back to back with each other Valve structure. The valve structure of the hydraulic shock absorber according to any one of claims 1 to 5 , wherein the piston is made of only a resin material.

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