JP2024048444A - Hydraulic shock absorber - Google Patents

Abstract

[Problem] To provide a hydraulic shock absorber capable of suppressing deterioration in durability of an elastic body. [Solution] A hydraulic shock absorber having a cylinder (17), a piston slidably fitted in the cylinder (17), a piston rod (50) inserted into the cylinder (17) and connected to the piston, a support member (80) attached to the piston rod (50) when the piston rod (50) is inserted, an extension limiting member disposed on the opposite side of the support member (80) from the piston and attached to the cylinder (17), and an elastic body (81) attached to the piston rod (50) when the piston rod (50) is inserted, and disposed between the support member (80) and the extension limiting member to abut against the extension limiting member when the piston rod (50) is fully extended, thereby absorbing impact, and a plurality of recesses (97) are provided at predetermined intervals in the circumferential direction on an opposing surface (93) of the support member (80) that abuts against the elastic body (81). [Selected Figure] Figure 2

Description

The present invention relates to a hydraulic shock absorber.

In a hydraulic shock absorber equipped with a stopper member provided on a piston rod and a rebound cushion made of an elastic body such as natural rubber or synthetic rubber, or synthetic resin, placed on the stopper member, a recess is provided on the contact portion of the rebound cushion that contacts the stopper member to prevent oil film rupture (see, for example, Patent Document 1).

There is also a device in which a recess is provided in a plastic thrust washer that is provided between the upper rebound collar of the rebound spring unit and the rod guide (see, for example, Patent Document 2).

JP 2006-200558 A Patent No. 6169769

In hydraulic shock absorbers, when an elastic body is used to absorb the impact when the piston rod is fully extended, there is a demand for suppressing the deterioration of the durability of this elastic body.

Therefore, the present invention aims to provide a hydraulic shock absorber that can suppress the deterioration of the durability of the elastic body.

In order to achieve the above object, one aspect of the present invention is a hydraulic shock absorber having a cylinder, a piston slidably fitted in the cylinder, a piston rod inserted into the cylinder and connected to the piston, a support member provided on the piston rod when the piston rod is inserted, an extension limiting member disposed on the opposite side of the support member to the piston and provided on the cylinder, and an elastic body provided on the piston rod when the piston rod is inserted and disposed between the support member and the extension limiting member to abut against the extension limiting member when the piston rod is fully extended, thereby absorbing impact, and the support member has a plurality of recesses provided at predetermined intervals in the circumferential direction on the opposing surface that abuts against the elastic body.

The present invention makes it possible to suppress the deterioration of the durability of the elastic body.

1 is a cross-sectional view showing a hydraulic shock absorber according to a first embodiment of the present invention. 1 is a cross-sectional view showing a main part of a hydraulic shock absorber according to a first embodiment of the present invention. FIG. 2 is a plan view showing a support member of the hydraulic shock absorber according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view showing a support member of the hydraulic shock absorber according to the first embodiment of the present invention. FIG. 11 is a plan view showing a support member of a hydraulic shock absorber according to a second embodiment of the present invention. FIG. 11 is a cross-sectional view showing a support member of a hydraulic shock absorber according to a second embodiment of the present invention. FIG. 13 is a plan view showing a support member of a hydraulic shock absorber according to a third embodiment of the present invention. FIG. 11 is a cross-sectional view showing a support member of a hydraulic shock absorber according to a third embodiment of the present invention. FIG. 11 is a cross-sectional view of a main part of a hydraulic shock absorber according to a first other application example of the first to third embodiments of the present invention. FIG. 11 is a cross-sectional view of a main part showing a hydraulic shock absorber according to a second other application example of the first to third embodiments of the present invention.

[First embodiment]
The first embodiment will be described with reference to FIGS.
FIG. 1 shows a hydraulic shock absorber 11 of a first embodiment. This hydraulic shock absorber 11 is used in a suspension device of a vehicle such as an automobile or a railway vehicle. Specifically, the hydraulic shock absorber 11 is used in a suspension device of an automobile. The hydraulic shock absorber 11 is a twin-tube hydraulic shock absorber equipped with a cylinder 17 having an inner tube 15 and an outer tube 16. The inner tube 15 is cylindrical. The outer tube 16 is a bottomed tube having a larger diameter than the inner tube 15. The outer tube 16 is provided radially outside the inner tube 15 and coaxially with the inner tube 15. A reservoir chamber 18 is formed between the outer tube 16 and the inner tube 15.

The outer cylinder 16 has a body 20 and a bottom 21. The body 20 is cylindrical. The bottom 21 closes one axial end of the body 20. The side of the body 20 opposite the bottom 21 is an opening 22. The opening 22 of the outer cylinder 16 is also provided at one axial end of the cylinder 17. The bottom 21 of the outer cylinder 16 is also provided at the other axial end of the cylinder 17. In other words, one axial end of the cylinder 17 is open as the opening 22, and the other axial end is closed. A bracket 23 is fixed to the outside of the body 20 of the outer cylinder 16.

The hydraulic shock absorber 11 includes a valve body 25 and a rod guide 26 (extension restriction member).

The valve body 25 is annular and is provided at one axial end of the inner cylinder 15 and the outer cylinder 16. The valve body 25 constitutes the base valve 30, and its outer periphery is stepped. The valve body 25 is placed on the bottom 21. At that time, the valve body 25 is positioned radially relative to the outer cylinder 16 at the large diameter part of its outer periphery.

The rod guide 26 is annular and is provided at the other axial end of the inner cylinder 15 and the outer cylinder 16. The rod guide 26 is provided on the opening 22 side of the cylinder 17. The rod guide 26 has a rod guide body 32 and a collar 33.

The rod guide body 32 is made of metal and has a circular ring shape. The rod guide body 32 has a large diameter portion 35 and a small diameter portion 36 on its outer periphery. The outer diameter of the large diameter portion 35 is larger than the outer diameter of the small diameter portion 36. Therefore, the rod guide body 32 has a stepped outer periphery.

The collar 33 is cylindrical. The collar 33 is made of a metal cylinder whose inner circumferential surface is coated with a material having high sliding properties. The collar 33 is fitted and fixed to the inner circumferential portion of the rod guide body 32.

The rod guide 26 fits into the inner circumference of the opening 22 side of the barrel 20 of the outer tube 16 at the large diameter portion 35 of the rod guide body 32. The end face 37 of the rod guide 26 at the end opposite the large diameter portion 35 in the axial direction is flat and extends perpendicular to the central axis of the rod guide 26. The end face 37 is formed on the rod guide body 32 and the collar 33.

The inner cylinder 15 is fitted at one end in the axial direction to the small diameter portion of the outer periphery of the valve body 25 until it abuts against the large diameter portion of the valve body 25 in the axial direction. The inner cylinder 15 is placed at one end in the axial direction on the bottom 21 of the outer cylinder 16 via the valve body 25. The inner cylinder 15 is fitted at the other end in the axial direction to the small diameter portion 36 of the rod guide main body 32 until it abuts against the large diameter portion 35 in the axial direction. The inner cylinder 15 is fitted at the other end to the body 20 of the outer cylinder 16 via the rod guide 26. In this state, the inner cylinder 15 is positioned axially and radially relative to the outer cylinder 16. Here, the space between the valve body 25 and the bottom 21 is connected to the inner cylinder 15 and the outer cylinder 16 via a passage groove 40 formed in the valve body 25. The space between the valve body 25 and the bottom 21 constitutes a reservoir chamber 18, as does the space between the inner cylinder 15 and the outer cylinder 16.

The hydraulic shock absorber 11 is provided with an annular rod seal 41. The rod seal 41 is provided on the opposite side of the bottom 21 of the rod guide 26 in the axial direction of the cylinder 17. This rod seal 41 is also fitted to the inner periphery of the body 20, similar to the rod guide 26. The outer cylinder 16 has an engagement portion 43 formed at the end opposite the bottom 21 of the body 20. The engagement portion 43 is formed by plastically deforming the body 20 radially inward by crimping such as curling. The rod seal 41 is sandwiched between the engagement portion 43 and the rod guide 26. At that time, the rod seal 41 is pressed against the inner periphery of the body 20 by the rod guide 26. As a result, the rod seal 41 closes the opening 22 of the outer cylinder 16. Specifically, the rod seal 41 is an oil seal.

The hydraulic shock absorber 11 is equipped with a piston 45. The piston 45 is slidably fitted in the inner tube 15 of the cylinder 17. The piston 45 divides the inner tube 15 into two chambers, a first chamber 48 and a second chamber 49. The first chamber 48 is provided between the piston 45 and the rod guide 26 in the inner tube 15. The second chamber 49 is provided between the piston 45 and the valve body 25 in the inner tube 15. The second chamber 49 is divided from the reservoir chamber 18 by the valve body 25. In the cylinder 17, oil liquid L is sealed in the first chamber 48 and the second chamber 49 as a working fluid. In the cylinder 17, gas G and oil liquid L are sealed in the reservoir chamber 18 as a working fluid.

The hydraulic shock absorber 11 is provided with a piston rod 50. One axial end of the piston rod 50 is inserted into the cylinder 17. The piston rod 50 is connected to the piston 45 at one end. The axial middle portion of the piston rod 50 is inserted through the rod guide 26 and the rod seal 41. The piston rod 50 extends to the outside of the cylinder 17 at the other end. The piston rod 50 is made of metal and passes through the first chamber 48. The piston rod 50 does not pass through the second chamber 49. Therefore, the first chamber 48 is a rod side chamber through which the piston rod 50 passes. The second chamber 49 is a bottom side chamber on the bottom 21 side of the cylinder 17. In the hydraulic shock absorber 11, the bracket 23 attached to the body 20 of the outer cylinder 16 is connected to the wheel side of the vehicle, and the portion of the piston rod 50 extending from the cylinder 17 to the outside is connected to the body side of the vehicle.

The piston rod 50 has a main shaft portion 51 and a mounting shaft portion 52 .
The mounting shaft portion 52 has an outer diameter smaller than the outer diameter of the main shaft portion 51. The mounting shaft portion 52 side of the piston rod 50 is inserted into the cylinder 17.

The outer peripheral surface 51a of the main shaft portion 51 is cylindrical. The main shaft portion 51 of the piston rod 50 passes through the rod guide 26 and the rod seal 41. An engagement groove 53 is formed in the main shaft portion 51 of the piston rod 50. The engagement groove 53 is recessed radially inward from the outer peripheral surface 51a of the main shaft portion 51. The engagement groove 53 is annular and coaxial with the outer peripheral surface 51a of the main shaft portion 51. The engagement groove 53 is formed in a portion of the main shaft portion 51 that is located inside the inner tube 15 and is located between the piston 45 and the rod guide 26.

The rod guide 26 and the rod seal 41 are provided on the side of the cylinder 17 from which the piston rod 50 extends. The rod guide 26 slidably supports the piston rod 50. The piston rod 50 is guided by the rod guide 26 at the outer peripheral surface 51a of the main shaft portion 51. The end surface 37 of the rod guide 26 extends perpendicular to the central axis of the piston rod 50. The piston rod 50 moves axially together with the piston 45 relative to the cylinder 17. During the extension stroke of the hydraulic shock absorber 11, in which the piston rod 50 increases the amount of protrusion from the cylinder 17, the piston 45 moves toward the first chamber 48. During the contraction stroke of the hydraulic shock absorber 11, in which the piston rod 50 decreases the amount of protrusion from the cylinder 17, the piston 45 moves toward the second chamber 49.

The rod seal 41 is provided on the side where the piston rod 50 of the cylinder 17 extends, i.e., on the opening 22 side of the outer tube 16. The rod seal 41, together with the rod guide 26, seals between the body 20 of the outer tube 16 and the main shaft 51 of the piston rod 50, preventing the oil liquid L in the inner tube 15 and the gas G and oil liquid L in the reservoir chamber 18 from leaking out to the outside.

The piston 45 is formed with a passage 55 and a passage 56. Both the passage 55 and the passage 56 pass through the piston 45 in the axial direction. The passages 55 and 56 can communicate between the first chamber 48 and the second chamber 49. The hydraulic shock absorber 11 includes a disk valve 57 and a disk valve 58. The disk valve 57 is provided on the side of the piston 45 opposite the bottom 21 in the axial direction. The disk valve 57 is annular, and closes the passage 55 by abutting against the piston 45. The disk valve 58 is provided on the bottom 21 side in the axial direction of the piston 45. The disk valve 58 is annular, and closes the passage 56 by abutting against the piston 45. The disk valves 57 and 58 are attached to the piston rod 50 together with the piston 45.

When the piston rod 50 moves toward the compression side, increasing the amount of penetration into the inner tube 15 and the outer tube 16, and the piston 45 moves in the direction narrowing the second chamber 49, the pressure in the second chamber 49 becomes higher than the pressure in the first chamber 48. Then, the disc valve 57 opens the passage 55, allowing the oil L in the second chamber 49 to flow into the first chamber 48. At that time, the disc valve 57 generates a damping force.

When the piston rod 50 moves to the extension side, increasing the amount of protrusion from the inner tube 15 and the outer tube 16, and the piston 45 moves in the direction narrowing the first chamber 48, the pressure in the first chamber 48 becomes higher than the pressure in the second chamber 49. Then, the disc valve 58 opens the passage 56, allowing the oil L in the first chamber 48 to flow into the second chamber 49. At that time, the disc valve 58 generates a damping force.

At least one of the piston 45 and the disk valve 57 has a fixed orifice (not shown). This fixed orifice allows communication between the first chamber 48 and the second chamber 49 through the passage 55 even when the disk valve 57 is in the most blocked state of the passage 55.

At least one of the piston 45 and the disk valve 58 has a fixed orifice (not shown). This fixed orifice allows communication between the first chamber 48 and the second chamber 49 through the passage 56 even when the disk valve 58 is in the most blocked state of the passage 56.

The valve body 25 is formed with a liquid passage 61 and a liquid passage 62. Both the liquid passage 61 and the liquid passage 62 pass through the valve body 25 in the axial direction. Both the liquid passages 61 and 62 can communicate between the second chamber 49 and the reservoir chamber 18.

The base valve 30 includes a disk valve 65 and a disk valve 66. The disk valve 65 is provided on the bottom 21 side of the valve body 25 in the axial direction. The disk valve 65 closes the liquid passage 61 by abutting against the valve body 25. The disk valve 66 is provided on the opposite side of the valve body 25 from the bottom 21 in the axial direction. The disk valve 66 closes the liquid passage 62 by abutting against the valve body 25. The base valve 30 has a pin 68. This pin 68 attaches the disk valves 65, 66 to the valve body 25. The valve body 25, the disk valves 65, 66, the pin 68, etc., constitute the base valve 30.

When the piston rod 50 moves toward the contraction side and the piston 45 moves in a direction narrowing the second chamber 49, the pressure in the second chamber 49 becomes higher than the pressure in the reservoir chamber 18. Then, in the base valve 30, the disk valve 65 opens the fluid passage 61, allowing the oil L in the second chamber 49 to flow into the reservoir chamber 18. At that time, the disk valve 65 generates a damping force. When the piston rod 50 moves toward the extension side and the piston 45 moves toward the first chamber 48, the pressure in the second chamber 49 becomes lower than the pressure in the reservoir chamber 18. Then, in the base valve 30, the disk valve 66 opens the fluid passage 62, allowing the oil L in the reservoir chamber 18 to flow into the second chamber 49. The disk valve 66 is a suction valve that allows the oil L to flow from the reservoir chamber 18 into the second chamber 49 without generating any substantial damping force.

As shown in FIG. 2, the hydraulic shock absorber 11 includes a support member 80 and a rebound cushion 81 (elastic body).

The support member 80 is made of metal and has a circular ring shape. The support member 80 is formed as a single piece without any seams. The support member 80 has a support portion 91 and a fixing portion 92.

As shown in Figures 3 and 4, the support part 91 is disk-shaped. The opposing surface 93 of the support part 91 on one axial side thereof is annular. As shown in Figure 2, the outer diameter of the support part 91 is smaller than the inner diameter of the inner tube 15.

As shown in FIG. 4, the fixing portion 92 protrudes from the inner peripheral edge of the support portion 91 on the side opposite the opposing surface 93 in the axial direction of the support portion 91. The fixing portion 92 is cylindrical. The outer diameter of the fixing portion 92 is smaller than the outer diameter of the support portion 91.

The opposing surface 93 has a planar base surface portion 95 that extends perpendicular to the central axis of the support portion 91, an inner arc-shaped recess 96 (recess) shown in FIG. 3 that is a bottomed groove recessed from the base surface portion 95 toward the fixed portion 92 in the axial direction of the support member 80, and an outer arc-shaped recess 97 (recess) shown in FIG. 4 that is a bottomed groove recessed from the base surface portion 95 toward the fixed portion 92 in the axial direction of the support member 80.

As shown in FIG. 3, the inner arc-shaped recess 96 has an arc shape when the opposing surface 93 is viewed in the axial direction of the support member 80. The inner arc-shaped recess 96 has an outer wall surface 101, an inner wall surface 102, a pair of side wall surfaces 103, and a bottom surface 104.

The outer wall surface 101 is provided on the radially outer side of the inner arc-shaped recess 96 of the support member 80 and faces the radially inward side of the support member 80. The outer wall surface 101 is shaped as a part of a cylindrical surface centered on the central axis of the support member 80.

The inner wall surface 102 is provided on the inner side of the inner arc-shaped recess 96 in the radial direction of the support member 80, and faces the outer side in the radial direction of the support member 80. The inner wall surface 102 is provided on the inner side of the outer wall surface 101 in the radial direction of the support member 80. The inner wall surface 102 is shaped as a part of a cylindrical surface centered on the central axis of the support member 80. The inner wall surface 102 is positioned circumferentially of the support member 80 in the same position as the outer wall surface 101.

The pair of side wall surfaces 103 are both planar along the radial and axial directions of the support member 80 and face each other. One side wall surface 103 connects the edges of the outer wall surface 101 and the inner wall surface 102 at one end in the circumferential direction of the support member 80, and the other side wall surface 103 connects the edges of the outer wall surface 101 and the inner wall surface 102 at the other end in the circumferential direction of the support member 80.

The bottom surface 104 connects the edge portions of the outer wall surface 101, the inner wall surface 102, and the pair of side wall surfaces 103 on the fixed portion 92 side in the axial direction of the support member 80. The bottom surface 104 is a flat surface extending parallel to the base surface portion 95.

The opposing surface 93 has multiple, specifically four, inner arc-shaped recesses 96 of the same shape formed at equidistant positions from the central axis of the support member 80. In other words, all outer wall surfaces 101 of all inner arc-shaped recesses 96 are arranged on the same cylindrical surface centered on the central axis of the support member 80. Also, all inner wall surfaces 102 of all inner arc-shaped recesses 96 are arranged on the same cylindrical surface centered on the central axis of the support member 80.

The multiple inner arc-shaped recesses 96 are arranged at a predetermined interval in the circumferential direction of the support member 80. In other words, the support member 80 has multiple inner arc-shaped recesses 96 on the opposing surface 93 at a predetermined interval in the circumferential direction of the support member 80. Specifically, the multiple inner arc-shaped recesses 96 are arranged at equal intervals in the circumferential direction of the support member 80. The inner arc-shaped recesses 96 are formed on the opposing surface 93 by machining or plastic processing.

The outer arc-shaped recess 97 has an arc shape when the opposing surface 93 is viewed in the axial direction of the support member 80. The outer arc-shaped recess 97 has an outer wall surface 111, an inner wall surface 112, a pair of side wall surfaces 113, and a bottom surface 114.

The outer wall surface 111 is provided on the outer side of the outer arc-shaped recess 97 in the radial direction of the support member 80 and faces inward in the radial direction of the support member 80. The outer wall surface 111 is shaped as a part of a cylindrical surface centered on the central axis of the support member 80.

The inner wall surface 112 is provided on the inside of the outer arc-shaped recess 97 in the radial direction of the support member 80, and faces the outside of the support member 80 in the radial direction. The inner wall surface 112 is provided on the inside of the outer wall surface 111 in the radial direction of the support member 80. The inner wall surface 112 is shaped as a part of a cylindrical surface centered on the central axis of the support member 80. The inner wall surface 112 is positioned circumferentially of the support member 80 in the same position as the outer wall surface 111.

The pair of side wall surfaces 113 are both planar along the radial and axial directions of the support member 80 and face each other. One side wall surface 113 connects the edges of the outer wall surface 111 and the inner wall surface 112 at one end in the circumferential direction of the support member 80, and the other side wall surface 113 connects the edges of the outer wall surface 111 and the inner wall surface 112 at the other end in the circumferential direction of the support member 80.

The bottom surface 114 connects the edge portions of the outer wall surface 111, the inner wall surface 112, and the pair of side wall surfaces 113 on the fixed portion 92 side in the axial direction of the support member 80. The bottom surface 114 is a flat surface extending parallel to the base surface portion 95.

The opposing surface 93 has multiple, specifically four, outer arc-shaped recesses 97 of the same shape formed at equidistant positions from the central axis of the support member 80. In other words, all of the outer wall surfaces 111 of all of the outer arc-shaped recesses 97 are arranged on the same cylindrical surface centered on the central axis of the support member 80. Also, all of the inner wall surfaces 112 of all of the outer arc-shaped recesses 97 are arranged on the same cylindrical surface centered on the central axis of the support member 80.

The multiple outer arc-shaped recesses 97 are arranged at a predetermined interval in the circumferential direction of the support member 80. In other words, the multiple outer arc-shaped recesses 97 are provided on the opposing surface 93 of the support member 80 at a predetermined interval in the circumferential direction of the support member 80. Specifically, the multiple outer arc-shaped recesses 97 are arranged at equal intervals in the circumferential direction of the support member 80. The outer arc-shaped recesses 97 are formed on the opposing surface 93 by machining or plastic processing.

The inner wall surface 112 of the outer arc-shaped recess 97 is provided radially outward of the support member 80 relative to the outer wall surface 101 of the inner arc-shaped recess 96. Therefore, the outer arc-shaped recesses 97 are provided radially outward of the support member 80 relative to the inner arc-shaped recesses 96. The support member 80 has a plurality of inner arc-shaped recesses 96 and a plurality of outer arc-shaped recesses 97 provided on the opposing surface 93 at a predetermined interval in the radial direction of the support member 80. The inner arc-shaped recesses 96 and the outer arc-shaped recesses 97 are provided completely apart in the radial direction of the support member 80.

In the circumferential direction of the support member 80, the outer arc-shaped recesses 97 and the inner arc-shaped recesses 96 are alternately arranged at equal pitches. The outer arc-shaped recesses 97 are all offset in position in the circumferential direction of the support member 80 with respect to the inner arc-shaped recesses 96. In other words, the inner arc-shaped recesses 96 are all offset in position in the circumferential direction of the support member 80 with respect to the outer arc-shaped recesses 97. Therefore, the outer arc-shaped recesses 97 and the inner arc-shaped recesses 96 do not overlap in position in the circumferential direction of the support member 80. The inner arc-shaped recesses 96 and the outer arc-shaped recesses 97 are concentric, but are arranged with a completely shifted phase in the circumferential direction. The inner arc-shaped recesses 96 and the outer arc-shaped recesses 97 may partially overlap in position in the circumferential direction of the support member 80.

All of the outer arc-shaped recesses 97 and all of the inner arc-shaped recesses 96 of the opposing surface 93 are entirely formed within the range of the base surface portion 95. In other words, none of the outer arc-shaped recesses 97 and all of the inner arc-shaped recesses 96 penetrate into either the radially outer edge of the base surface portion 95 or the radially inner edge of the base surface portion 95.

Before the support member 80 is attached to the piston rod 50, the fixing portion 92 is cylindrical as shown in FIG. 4. In this state, the support member 80 is fitted to the main shaft portion 51 of the piston rod 50 in a direction in which the fixing portion 92 protrudes from the support portion 91 toward the piston 45 as shown in FIG. 1. The fixing portion 92 is then crimped radially inward while being aligned with the engagement groove 53 of the piston rod 50. As a result, the fixing portion 92 is plastically deformed and enters the engagement groove 53, and the support member 80 is fixed to the piston rod 50. In this state, the base surface portion 95 of the support portion 91 expands perpendicularly to the central axis of the piston rod 50 as shown in FIG. 2.

The support member 80 is attached to the piston rod 50 with the main shaft portion 51 of the piston rod 50 inserted inside. As shown in FIG. 1, the rod guide 26 is disposed on the opposite side of the support member 80 from the piston 45.

Specifically, the support member 80 is made of hot-rolled steel plate (SPHC material) for press working. However, the support member 80 is not limited to this, and can be made of cold-rolled steel plate (SPCC material), surface-treated steel plate, stainless steel plate, aluminum plate, etc. In this case, the support member 80 is formed using plastic processing such as sheet metal, forging, or rolling, or cutting processing.

As shown in FIG. 2, the rebound cushion 81 is an elastic body made of an elastic material. The rebound cushion 81 is molded seamlessly as a single piece. The rebound cushion 81 is annular, and its outer diameter is smaller than the inner diameter of the inner tube 15. The rebound cushion 81 has an inner circumferential surface 121, an outer circumferential surface 122, an end surface 123, and an end surface 124.

The inner peripheral surface 121 is cylindrical.

The outer peripheral surface 122 has an arc-shaped cross section in a plane including the central axis of the rebound cushion 81. The outer peripheral surface 122 is curved so as to be convex outward in the radial direction of the rebound cushion 81.

The end surface 123 is a tapered surface whose entirety is centered on the central axis of the rebound cushion 81. The end surface 123 has a convex shape that protrudes outward from the rebound cushion 81 in the axial direction of the rebound cushion 81. The end surface 123 does not have any recesses such as grooves or holes.

End face 124 is a tapered surface whose entirety is centered on the central axis of rebound cushion 81. End face 124 has a shape that protrudes outward from rebound cushion 81 in the axial direction of rebound cushion 81. In other words, end face 123 and end face 124 have shapes that protrude in opposite directions. End face 124 does not have any recesses such as grooves or holes. Rebound cushion 81 is mirror symmetrical.

The rebound cushion 81 is provided on the piston rod 50 with the main shaft portion 51 of the piston rod 50 inserted inside. The rebound cushion 81 is disposed between the support member 80 and the rod guide 26 as shown in FIG. 1. In this case, as shown in FIG. 2, the end face 123 of the rebound cushion 81 faces the opposing surface 93 of the support member 80, and the end face 124 faces the end face 37 of the rod guide 26 shown in FIG. 1. Therefore, the opposing surface 93 of the support member 80 faces the end face 123 of the rebound cushion 81, and the opposing surface 93 abuts against the end face 123 depending on the relative position with the rebound cushion 81. In addition, the end face 37 of the rod guide 26 shown in FIG. 1 faces the end face 124 of the rebound cushion 81 shown in FIG. 2, and the end face 37 shown in FIG. 1 abuts against the end face 124 shown in FIG. 2 depending on the relative position with the rebound cushion 81. The support member 80 is fixed to the piston rod 50 and is a stopper that determines the axial movement range of the rebound cushion 81 relative to the piston rod 50.

The rebound cushion 81 is specifically made of NBR (nitrile rubber). However, it is not limited to this, and the rebound cushion 81 may be made of NR (natural rubber), IR (synthetic natural rubber), SBR (styrene butadiene rubber), BR (butadiene rubber), CR (chloroprene rubber), IIR (butyl rubber), EPDM (ethylene propylene rubber), ACM (acrylic rubber), U (urethane rubber), H-NBR (hydrogenated nitrile rubber), VMQ (silicone rubber), FKM (fluororubber), a mixture of the above rubbers, TPE (thermoplastic elastomer), PE (polyethylene), PP (polypropylene), PS (polystyrene), PA (polyamide), PPS (polyphenylene sulfide), PTFE (polytetrafluoroethylene), or a filler with a reinforcing effect such as a carbon-based reinforcing material or glass fiber.

In the hydraulic shock absorber 11 configured as above, the rebound cushion 81 basically moves together with the piston rod 50 with the end face 123 in contact with the opposing face 93 of the support member 80. Then, when the piston rod 50 moves in the direction extending from the cylinder 17 and is positioned at a predetermined position on the fully extended side, the end face 124 of the rebound cushion 81 comes into contact with the end face 37 of the rod guide 26. When the piston rod 50 moves further toward the fully extended side, the rebound cushion 81 is pressed against the rod guide 26 by the support member 80 and is compressed and deformed in the axial direction, thereby applying a resistance force to the piston rod 50 via the support member 80 and stopping the piston rod 50 at the fully extended position. The rebound cushion 81 comes into contact with the rod guide 26 when the piston rod 50 is fully extended, and reduces the impact when the piston rod 50 is stopped relative to the cylinder 17.

The rebound cushion 81 elastically deforms when fully extended, and as the elastic deformation progresses, it deforms so as to expand radially outward toward the inner tube 15. At the beginning of the elastic deformation, the rebound cushion 81 abuts against the periphery of the multiple inner arc-shaped recesses 96 located radially inside the opposing surface 93 of the support member 80, blocking the multiple inner arc-shaped recesses 96. At the end of the elastic deformation, the rebound cushion 81 abuts for the first time against the periphery of the multiple outer arc-shaped recesses 97 located radially outside the opposing surface 93, blocking the multiple outer arc-shaped recesses 97.

The above-mentioned Patent Document 1 discloses a hydraulic shock absorber that includes a support member attached to a piston rod and a rebound cushion made of an elastic body such as natural rubber or synthetic rubber, or synthetic resin, placed on the support member, in which a recess is provided as an oil film break prevention part in the contact part of the rebound cushion that contacts the support member. In addition, the above-mentioned Patent Document 2 discloses a recess provided in a resin thrust washer that is provided between the upper rebound collar of the rebound spring unit and the rod guide.

In a hydraulic shock absorber, when the piston rod is fully extended and in a steering state, the rebound cushion may rotate relative to the support member while being pressed against the support member. At this time, the oil film between the rebound cushion and the support member may break, causing abnormal noise and reducing durability against input in the rotational (torsional) direction. In order to prevent abnormal noise and reduced durability against input in the rotational direction, for example, in Patent Document 1, a recess is provided in the rebound cushion to prevent oil breakage, and hydraulic fluid is actively guided into the recess to prevent oil film breakage and reduce frictional resistance.

Here, the rebound cushion is an elastic body, and it absorbs the impact when it is fully extended by elastic deformation. For this reason, when providing a recess in the rebound cushion, it is necessary to provide a relatively large recess so that the oil film, i.e., the gap, can be maintained even after elastic deformation. The larger the recess in the rebound cushion, the thinner the surrounding area becomes. Since the rebound cushion is an elastic body, the formation of a recess may reduce its durability against axial input. In other words, if the impact when it is fully extended is large, the distortion in the surrounding area of the recess in the rebound cushion may become locally large, and the rebound cushion may break starting from the recess. In this way, when a recess is provided in the rebound cushion, the durability against rotational (torsional) input is improved compared to a shape without a recess, but the durability against axial input may be reduced.

In the hydraulic shock absorber 11 of the first embodiment, a plurality of inner arc-shaped recesses 96 are provided at a predetermined interval in the circumferential direction on the opposing surface 93 of the support member 80 that abuts against the rebound cushion 81. In addition, a plurality of outer arc-shaped recesses 97 are provided at a predetermined interval in the circumferential direction of the support member 80 on the opposing surface 93 of the support member 80. This eliminates the need to provide recesses in the rebound cushion 81, which is an elastic body, and makes it possible to suppress local strain that occurs in the rebound cushion 81 during compression deformation. Therefore, it is possible to suppress a decrease in the durability of the rebound cushion 81 against axial input. In addition, since the oil liquid L can be stored in the inner arc-shaped recesses 96 and the outer arc-shaped recesses 97 of the support member 80, it is possible to suppress the oil film break between the rebound cushion 81 and the support member 80 when the rebound cushion 81 rotates relative to the support member 80 while being pressed against the support member 80, making it easier to rotate. Therefore, it is possible to suppress a decrease in the durability of the rebound cushion 81 in the rotational direction and suppress the generation of abnormal noise, compared to the case where a groove is provided on the rebound cushion side. Furthermore, when the rebound cushion 81 and the support member 80 rotate relative to each other, the contact surface of the rebound cushion 81 with the multiple inner arc-shaped recesses 96 and multiple outer arc-shaped recesses 97 of the support member 80 changes and is not always constant. This distributes the load generated at the contact portion of the rebound cushion 81 with the support member 80. This makes it possible to more reliably suppress the deterioration of the durability of the rebound cushion 81 in the rotational direction than when a groove is provided on the rebound cushion side. Therefore, the hydraulic shock absorber 11 makes it possible to suppress the deterioration of the durability of the rebound cushion 81, which is an elastic body.

The hydraulic shock absorber 11 also has a plurality of inner arc-shaped recesses 96 and a plurality of outer arc-shaped recesses 97 on the opposing surface 93, which are spaced at predetermined intervals in the radial direction of the support member 80. This further prevents the oil film from breaking between the rebound cushion 81 and the support member 80, further prevents the rebound cushion 81 from losing durability in the rotational direction, and further prevents the generation of abnormal noise.

In addition, since the hydraulic shock absorber 11 has an inner arc-shaped recess 96 and an outer arc-shaped recess 97 that are arc-shaped when the opposing surface 93 is viewed in the axial direction of the support member 80, the opening area of the inner arc-shaped recess 96 and the outer arc-shaped recess 97 can be increased. This further reduces the oil film breakdown between the rebound cushion 81 and the support member 80, further reduces the deterioration of the durability of the rebound cushion 81 in the rotational direction, and further reduces the generation of abnormal noise.

In addition, the hydraulic shock absorber 11 has an outer arc-shaped recess 97 and an inner arc-shaped recess 96 that are not inserted into either the radially outer edge or the radially inner edge of the base surface portion 95, and are provided within the range of the base surface portion 95. Therefore, when the piston rod is fully extended, the opening of the outer arc-shaped recess 97 and the opening of the inner arc-shaped recess 96 are blocked by the end face 123 of the rebound cushion 81, and the oil liquid L that had accumulated in the outer arc-shaped recess 97 and the inner arc-shaped recess 96 before the piston rod is fully extended remains in the outer arc-shaped recess 97 and the inner arc-shaped recess 96 even when the piston rod is fully extended. Therefore, the oil film between the rebound cushion 81 and the support member 80 is further suppressed, the durability of the rebound cushion 81 in the rotational direction is further suppressed, and the generation of abnormal noise is further suppressed.

In addition, the hydraulic shock absorber 11 has a support member 80 made of metal or the like that is more durable than the rebound cushion 81, which is an elastic body (rubber or the like), so there is no risk of permanent deformation (plastic deformation) occurring in the support member 80, causing the outer arc-shaped recess 97 and the inner arc-shaped recess 96, which are oil grooves, to disappear.

[Second embodiment]
Next, the second embodiment will be described with a focus on differences from the first embodiment, mainly based on Figures 5 and 6. Note that parts common to the first embodiment will be designated by the same names and reference numerals.

In the second embodiment, a support member 80A shown in FIG. 5 and FIG. 6, which is partially different from the support member 80, is used instead of the support member 80. The support member 80A has a support portion 91A that is partially different from the support portion 91. The support portion 91A has an opposing surface 93A that is partially different from the opposing surface 93 instead of the opposing surface 93.

The opposing surface 93A has a base surface portion 95A that is a plane extending perpendicular to the central axis of the disk-shaped support portion 91A, a first linear recess 96A (recess) consisting of a bottomed groove recessed from the base surface portion 95A toward the fixed portion 92 in the axial direction of the support member 80A, and a second linear recess 97A (recess) consisting of a bottomed groove recessed from the base surface portion 95A toward the fixed portion 92 in the axial direction of the support member 80A.

The first linear recess 96A is linear and extends in a first direction along the radial direction of the support portion 91A. The first linear recess 96A penetrates at least one of the inner and outer circumferential surfaces of the support portion 91A. A plurality of first linear recesses 96A are formed on the opposing surface 93A, parallel to each other and spaced at equal intervals.

The second linear recess 97A is linear and extends in a second direction along the radial direction of the support portion 91A. The second direction is perpendicular to the first direction. Thus, the second linear recess 97A extends in a direction perpendicular to the first linear recess 96A. The second linear recess 97A penetrates at least one of the inner peripheral surface and the outer peripheral surface of the support portion 91A. A plurality of second linear recesses 97A are formed on the opposing surface 93A, parallel to each other and spaced apart at equal intervals. The distance between adjacent second linear recesses 97A is equal to the distance between adjacent first linear recesses 96A.

The first linear recesses 96A and the second linear recesses 97A are arranged so as to intersect. Thus, a plurality of first linear recesses 96A and a plurality of second linear recesses 97A are arranged in a lattice pattern on the opposing surface 93A. The adjacent first linear recesses 96A and the adjacent second linear recesses 97A and the adjacent second linear recesses 97A that intersect with the first linear recesses 96A and the second linear recesses 97A form an angular shape, specifically a quadrangle, when the opposing surface 93A is viewed in the axial direction of the support member 80A. On the opposing surface 93A, two adjacent first linear recesses 96A and two adjacent second linear recesses 97A form a number of angular recesses 131A that are formed in a rectangular shape when the opposing surface 93A is viewed in the axial direction of the support member 80A, and are evenly arranged in the first and second directions such that adjacent recesses in the first direction share the second linear recesses 97A, and adjacent recesses in the second direction share the first linear recesses 96A.

Therefore, the support member 80A has a plurality of rectangular recesses 131A on the opposing surface 93A, spaced at predetermined intervals in the circumferential direction of the support member 80A. Also, the support member 80A has a plurality of rectangular recesses 131A on the opposing surface 93A, spaced at predetermined intervals in the radial direction of the support member 80A.

All of the first linear recesses 96A and all of the second linear recesses 97A are formed in the support member 80A by surface texturing such as machining, plastic processing, or laser processing. Therefore, all of the angular recesses 131A are also formed in the support member 80A by surface texturing.

The support member 80A is fixed to the piston rod 50 (see FIG. 2) at the fixing portion 92 in the same manner as the support member 80. In this state, the base surface portion 95A of the support portion 91A extends perpendicularly to the central axis of the piston rod 50 (see FIG. 2). Then, the support member 80A is provided on the piston rod 50 (see FIG. 2) with the piston rod 50 (see FIG. 2) inserted inside. In addition, the rod guide 26 (see FIG. 1) is disposed on the opposite side of the support member 80A to the piston 45 (see FIG. 1).

The rebound cushion 81 (see FIG. 1) is disposed between the support member 80A and the rod guide 26 (see FIG. 1) in the same manner as in the first embodiment. In this case, the end face 123 (see FIG. 2) of the rebound cushion 81 (see FIG. 2) faces the opposing surface 93A of the support member 80A, and the end face 124 faces the end face 37 (see FIG. 1) of the rod guide 26 (see FIG. 1). Therefore, the opposing surface 93A of the support member 80A faces the end face 123 (see FIG. 2) of the rebound cushion 81 (see FIG. 2), and the opposing surface 93A abuts against the end face 123 (see FIG. 2) due to the relative position with the rebound cushion 81 (see FIG. 2).

In the second embodiment, the rebound cushion 81 (see FIG. 2) basically moves together with the piston rod 50 (see FIG. 2) with the end face 123 (see FIG. 2) in contact with the opposing surface 93A of the support member 80A. When the piston rod 50 (see FIG. 1) moves in the direction extending from the cylinder 17 (see FIG. 1) and is positioned at a predetermined position on the fully extended side, the rebound cushion 81 (see FIG. 2) abuts against the end face 37 (see FIG. 1) of the rod guide 26 (see FIG. 1) with the end face 124 (see FIG. 2). When the piston rod 50 (see FIG. 1) moves further to the fully extended side, the rebound cushion 81 (see FIG. 1) is pressed against the rod guide 26 (see FIG. 1) by the support member 80A and is compressed and deformed in the axial direction, applying a resistance force to the piston rod 50 (see FIG. 1) via the support member 80A, and stopping the piston rod 50 (see FIG. 1) at the fully extended position. As a result, the rebound cushion 81 (see FIG. 1) comes into contact with the rod guide 26 (see FIG. 1) when the piston rod 50 (see FIG. 1) is fully extended, mitigating the impact when the piston rod 50 (see FIG. 1) is stopped relative to the cylinder 17 (see FIG. 1).

In the second embodiment, a plurality of rectangular recesses 131A are provided at a predetermined interval in the circumferential direction of the support member 80A on the opposing surface 93A of the support member 80A that contacts the rebound cushion 81 (see FIG. 2). This eliminates the need to provide recesses in the elastic rebound cushion 81 (see FIG. 2). In addition, the oil liquid L can be stored in the rectangular recesses 131A of the support member 80A. Furthermore, when the rebound cushion 81 (see FIG. 2) and the support member 80A rotate relative to each other, the contact surface of the rebound cushion 81 (see FIG. 2) with the rectangular recesses 131A of the support member 80A changes and is no longer constant. Therefore, it is possible to suppress the deterioration of the durability of the elastic rebound cushion 81 (see FIG. 2).

In addition, the support member 80A of the second embodiment has a plurality of rectangular recesses 131A on the opposing surface 93A, which are spaced at a predetermined interval in the radial direction of the support member 80A. This further suppresses the oil film from breaking between the rebound cushion 81 (see FIG. 2) and the support member 80A, further suppresses the deterioration of the durability of the rebound cushion 81 (see FIG. 2) in the rotational direction, and further suppresses the generation of abnormal noise.

In addition, in the support member 80A of the second embodiment, the rectangular recess 131A has a rectangular shape when the opposing surface 93A is viewed in the axial direction of the support member 80A, so the rectangular recess 131A can be easily formed by surface texturing.

In addition to forming a rectangular recess 131A with two adjacent first linear recesses 96A and two adjacent second linear recesses 97A that intersect with the first linear recesses 96A, it is also possible to form a plurality of linear recesses so as to form a rectangular recess having another angular shape, such as a triangular shape. For example, a hexagonal or honeycomb-shaped rectangular recess may be formed with two parallel adjacent linear recesses, two parallel adjacent linear recesses, and two parallel adjacent linear recesses. Alternatively, multiple recesses may be formed by blasting.

[Third embodiment]
Next, the third embodiment will be described with a focus on differences from the first embodiment, mainly with reference to Figures 7 and 8. Note that parts common to the first embodiment will be designated by the same names and reference numerals.

In the third embodiment, a support member 80B shown in FIG. 7 and FIG. 8, which is partially different from the support member 80, is used instead of the support member 80. The support member 80B has a support portion 91B which is partially different from the support portion 91. The support portion 91B has an opposing surface 93B which is partially different from the opposing surface 93 instead of the opposing surface 93.

The opposing surface 93B is a flat surface extending perpendicular to the central axis of the disk-shaped support portion 91B. The opposing surface 93B is provided with through holes 141B (recesses) that are recessed from the opposing surface 93B toward the fixed portion 92 in the axial direction of the support member 80B and penetrate the support portion 91B in the axial direction. The support member 80B has a plurality of through holes 141B, specifically four, formed at equal intervals in the circumferential direction of the support member 80B. These through holes 141B are positioned at equal distances from the central axis of the support member 80B. These through holes 141B are formed in the support member 80B by machining.

The support member 80B is fixed to the piston rod 50 (see FIG. 2) at the fixing portion 92 in the same manner as the support member 80. In this state, the opposing surface 93B of the support portion 91B extends perpendicularly to the central axis of the piston rod 50 (see FIG. 2). Then, the support member 80B is provided on the piston rod 50 (see FIG. 2) with the piston rod 50 (see FIG. 2) inserted inside. In addition, the rod guide 26 (see FIG. 1) is disposed on the opposite side of the support member 80B to the piston 45 (see FIG. 1).

The rebound cushion 81 (see FIG. 1) is disposed between the support member 80B and the rod guide 26 (see FIG. 1) in the same manner as in the first embodiment. In this case, the end face 123 (see FIG. 2) of the rebound cushion 81 (see FIG. 2) faces the opposing surface 93B of the support member 80B, and the end face 124 (see FIG. 2) faces the end face 37 (see FIG. 1) of the rod guide 26 (see FIG. 1). Therefore, the opposing surface 93B of the support member 80B faces the end face 123 (see FIG. 2) of the rebound cushion 81 (see FIG. 2), and the opposing surface 93B abuts against the end face 123 (see FIG. 2) due to the relative position with the rebound cushion 81 (see FIG. 2).

In the third embodiment, the rebound cushion 81 (see FIG. 2) basically moves together with the piston rod 50 (see FIG. 2) with the end face 123 (see FIG. 2) in contact with the opposing face 93B of the support member 80B. When the piston rod 50 (see FIG. 1) moves in the direction extending from the cylinder 17 (see FIG. 1) and is positioned at a predetermined position on the fully extended side, the rebound cushion 81 (see FIG. 2) abuts against the end face 37 (see FIG. 1) of the rod guide 26 (see FIG. 1) with the end face 124 (see FIG. 2). When the piston rod 50 (see FIG. 1) moves further to the fully extended side, the rebound cushion 81 (see FIG. 2) is pressed against the rod guide 26 (see FIG. 1) by the support member 80B and is compressed and deformed in the axial direction, applying a resistance force to the piston rod 50 (see FIG. 1) via the support member 80B, and stopping the piston rod 50 (see FIG. 1) at the fully extended position. As a result, the rebound cushion 81 (see FIG. 1) comes into contact with the rod guide 26 (see FIG. 1) when the piston rod 50 (see FIG. 1) is fully extended, mitigating the impact when the piston rod 50 (see FIG. 1) is stopped relative to the cylinder 17 (see FIG. 1).

In the third embodiment, a plurality of through holes 141B are provided at a predetermined interval in the circumferential direction of the support member 80B on the opposing surface 93B of the support member 80B that abuts against the rebound cushion 81 (see FIG. 2). This eliminates the need to provide a recess in the rebound cushion 81 (see FIG. 2), which is an elastic body. In addition, the oil liquid L can be supplied to the rebound cushion 81 (see FIG. 2) from the plurality of through holes 141B of the support member 80B to keep it in contact with the rebound cushion 81 (see FIG. 2). Moreover, when the rebound cushion 81 (see FIG. 2) and the support member 80B rotate relative to each other, the abutment surface of the rebound cushion 81 (see FIG. 2) with the plurality of through holes 141B of the support member 80B changes and is no longer constant. Therefore, it is possible to suppress the deterioration of the durability of the rebound cushion 81 (see FIG. 2), which is an elastic body.

In addition, in the support member 80B of the third embodiment, the through hole 141B penetrates the support portion 91B of the support member 80B in the axial direction of the support member 80B, so that the oil liquid L can be actively supplied to keep it in contact with the rebound cushion 81 (see FIG. 2). This makes it possible to further suppress the deterioration of the durability of the rebound cushion 81 (see FIG. 2), which is an elastic body. In addition, the through hole 141B can be easily formed by machining.

When oil L flows through the through-hole 141B, if excessive fluid resistance occurs, the desired damping characteristics may deviate, leading to deterioration in ride comfort and handling stability. For this reason, it is desirable to prevent pressure differences as much as possible by, for example, making the end face 123 (see FIG. 2) of the rebound cushion 81 (see FIG. 2) flat and bringing the end face 123 (see FIG. 2) into surface contact with the opposing face 93B, so that the through-hole 141B is always blocked by the rebound cushion 81 (see FIG. 2).

{First other application example of the first to third embodiments}
In another first application example, as shown in FIG. 9, a stopper 151C, a support member 152C, a rebound spring 153C, a support member 80C, and a rebound cushion 81C which is an elastic body are provided between a piston (not shown) of a piston rod 50C which is inserted into an inner tube 15C and connected to a piston (not shown) and a rod guide 26C.

The stopper 151C is positioned closer to the rod guide 26C than the piston (not shown), and is fixed to the piston rod 50C with the piston rod 50C inserted inside.

The support member 152C is disposed between the stopper 151C and the rod guide 26C, and is attached to the piston rod 50C with the piston rod 50C inserted inside.

The rebound spring 153C is a coil spring that is disposed between the support member 152 and the rod guide 26C and is attached to the piston rod 50C with the piston rod 50C inserted inside.

The support member 80C is disposed between the rebound spring 153C and the rod guide 26C, and is provided on the piston rod 50C with the piston rod 50C inserted inside. The rod guide 26C is disposed on the opposite side of the support member 80C from the piston (not shown) and is provided on the inner tube 15C. The support member 80C is made of the same material as the support member 80. The support member 80C may be made of a resin material, and the support member 80 may be made of a metal material. The resin material may be TPE (thermoplastic elastomer), PA (polyamide), PPA (aromatic polyamide), PC (polycarbonate), POM (polyacetal), PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), PEEK (polyether ether ketone), PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxyalkane), or a material containing a filler with a reinforcing effect such as a carbon-based reinforcing material or glass fiber.

The rebound cushion 81C is disposed between the support member 80C and the rod guide 26C, and is attached to the piston rod 50C with the piston rod 50C inserted inside. The rebound cushion 81C is made of the same material as the rebound cushion 81. The rebound cushion 81C comes into contact with the rod guide 26C when the piston rod 50C is fully extended, mitigating the impact. The support member 80C then comes into contact with the rod guide 26C, compressing and deforming the rebound spring 153C, mitigating the impact.

In this other first application example, the opposing surface 93C of the support member 80C that abuts against the rebound cushion 81C can be configured as the opposing surface 93 including the base surface portion 95, inner arc-shaped recess 96, and outer arc-shaped recess 97 of the first embodiment, as the opposing surface 93A including the base surface portion 95A, first linear recess 96A, and second linear recess 97A of the second embodiment, or as the opposing surface 93B provided with the through hole 141B of the third embodiment.

{Second Application Example of the First to Third Embodiments}
In another second application example, as shown in FIG. 10, a stopper 151D, a support member 152D, a rebound spring 153D, a support member 80D, and a thrust washer 161D are provided between the piston of a piston rod 50D, which is inserted into an inner tube 15D and connected to a piston (not shown), and a rod guide (not shown).

The stopper 151D is positioned closer to the rod guide (not shown) than the piston (not shown), and is fixed to the piston rod 50D with the piston rod 50D inserted inside.

The support member 152D is disposed between the stopper 151D and a rod guide (not shown), and is attached to the piston rod 50D with the piston rod 50D inserted inside.

The rebound spring 153D is a coil spring that is disposed between the support member 152D and a rod guide (not shown) and is attached to the piston rod 50D with the piston rod 50D inserted inside.

The support member 80D is disposed between the rebound spring 153D and a rod guide (not shown), and is provided on the piston rod 50D with the piston rod 50D inserted inside. The rod guide (not shown) is disposed on the opposite side of the support member 80D from the piston (not shown) and is provided on the inner tube 15D. The support member 80D is made of the same material as the support member 80. The support member 80D may be made of a resin material, and the support member 80 may be made of a metal material. The resin material may be TPE (thermoplastic elastomer), PA (polyamide), PPA (aromatic polyamide), PC (polycarbonate), POM (polyacetal), PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), PEEK (polyether ether ketone), PTFE (polytetrafluoroethylene), PFA (perfluoroalkoxyalkane), or a material containing a filler with a reinforcing effect such as a carbon-based reinforcing material or glass fiber.

The thrust washer 161D is disposed between the support member 80D and a rod guide (not shown), and is attached to the piston rod 50D with the piston rod 50D inserted inside. The thrust washer 161D is made of a self-lubricating resin material. The thrust washer 161D comes into contact with the rod guide (not shown) when the piston rod 50D is fully extended. The rebound spring 153D then compresses and deforms to absorb the impact.

In this other second application example, the opposing surface 93D that abuts against the thrust washer 161D of the support member 80D can be configured as the opposing surface 93 including the base surface portion 95, inner arcuate recess 96, and outer arcuate recess 97 of the first embodiment, as the opposing surface 93A including the base surface portion 95A, first linear recess 96A, and second linear recess 97A of the second embodiment, or as the opposing surface 93B provided with the through hole 141B of the third embodiment.

11...hydraulic shock absorber, 17...cylinder, 26, 26C...rod guide (extension limiting member), 45...piston, 50, 50C...piston rod, 80, 80A, 80B, 80C...support member, 81, 81C...rebound cushion (elastic body), 93, 93A, 93B, 93C...opposing surface, 96...inner arc-shaped recess (recess), 97...outer arc-shaped recess (recess), 131B...rectangular recess (recess), 141B...through hole (recess).

Claims (5)

A cylinder;
A piston slidably fitted in the cylinder;
a piston rod inserted into the cylinder and connected to the piston;
a support member provided on the piston rod in a state where the piston rod is inserted;
an extension limiting member disposed on the opposite side of the support member to the piston and provided in the cylinder;
an elastic body that is provided on the piston rod when the piston rod is inserted and is disposed between the support member and the extension restricting member, and that comes into contact with the extension restricting member when the piston rod is fully extended to absorb impact;
A hydraulic shock absorber having
The support member has a plurality of recesses formed at predetermined intervals in the circumferential direction on an opposing surface that contacts the elastic body. The hydraulic shock absorber according to claim 1, wherein the plurality of recesses are provided at predetermined intervals in the radial direction on the opposing surface. The hydraulic shock absorber according to claim 1 or 2, wherein the recess is arc-shaped when the opposing surface is viewed in the axial direction of the support member. The hydraulic shock absorber according to claim 1 or 2, wherein the recess has an angular shape when the opposing surface is viewed in the axial direction of the support member. The hydraulic shock absorber according to claim 1 or 2, wherein the recess is a through hole that passes through the support member in the axial direction.

Images