Buffer

Abstract

This shock absorber comprises: a cylinder filled with an operating fluid; a piston which is slidably fitted into the cylinder and divides the inside of the cylinder into two compartments; a rod of which a first end part is coupled to the piston and a second end part protrudes from the cylinder; a passage that communicates with the one compartment and the other compartment inside the cylinder; a flexible plate-like first valve having a first support part that is provided in the passage and is supported on one side surface on the radial inside thereof, a second support part that is disposed further outside on the radial outside thereof than the first support part, and a biasing part at least a portion of which is provided further outside in the radial outside than the second support part and that biases the second support side; and a flexible member that comes into contact with the first support part and is able to deflect with the first valve.

Description

[Technical field]

[0001] The present invention relates to a shock absorber. This application claims priority based on Patent Application No. 2021-192030, filed in Japan on November 26, 2021, the contents of which are incorporated herein by reference. [Background technology]

[0002] Some shock absorbers use a flexible disk as a valve (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent No. 6722683 Summary of the Invention [Problem to be solved by the invention]

[0004] When a flexible plate-shaped valve is used, it is desirable to improve its durability.

[0005] Therefore, an object of the present invention is to provide a shock absorber that can improve the durability of a flexible plate-shaped valve. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, a shock absorber according to one embodiment of the present invention has a configuration including a cylinder filled with a working fluid, a piston slidably fitted within the cylinder and dividing the interior of the cylinder into two chambers, a rod having a first end fastened to the piston and a second end protruding from the cylinder, a passage connecting one chamber and the other chamber within the cylinder, a first support part provided in the passage and supported at one side on the radially inner side, a second support part arranged radially outward from the first support part and supported at one side, a flexible plate-shaped first valve having a biasing part at least a portion of which is arranged radially outward from the second support part and biases the second support part, and a flexible member abutting the first support part and being flexible together with the first valve. Effect of the Invention

[0007] According to the above-described aspect of the present invention, the durability of the flexible plate-shaped valve can be improved. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing a shock absorber according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a cross-sectional view showing a piston, a first damping force generating mechanism, a second damping force generating mechanism, a frequency variable mechanism, etc. of a shock absorber according to a first embodiment of the present invention. Specifically, it is an enlarged view of a part A in FIG. 1. Note that the dashed line indicated by the symbol CL indicates the central axis of the shock absorber. [Diagram 3] 2 is a half-side cross-sectional view showing a frequency sensitive mechanism etc. of the shock absorber of the first embodiment according to the present invention, specifically, an enlarged view of a portion B in FIG. [Figure 4] 2 is a half-side cross-sectional view showing a frequency sensitive mechanism and the like of a shock absorber according to a second embodiment of the present invention, specifically, an enlarged view of a portion B in FIG. [Diagram 5] 2 is a half-side cross-sectional view showing a frequency sensitive mechanism and the like of a shock absorber according to a third embodiment of the present invention, specifically, an enlarged view of a portion B in FIG. [Figure 6]2 is a half-side cross-sectional view showing a frequency sensitive mechanism and the like of a shock absorber according to a fourth embodiment of the present invention, specifically, an enlarged view of a portion B in FIG. [Figure 7] 2 is a half-side cross-sectional view showing a frequency sensitive mechanism and the like of a shock absorber according to a fifth embodiment of the present invention, specifically, an enlarged view of a portion B in FIG. [Figure 8] 2. It is a half-side cross-sectional view showing a frequency sensitive mechanism etc. of a shock absorber of a sixth embodiment according to the present invention.Specifically, it is an enlarged view of a part B of FIG. [Figure 9] 2. It is a half-side cross-sectional view showing a frequency sensitive mechanism etc. of a shock absorber of a seventh embodiment according to the present invention.Specifically, it is an enlarged view of a part B of FIG. [Figure 10] 2. It is a half-side cross-sectional view showing a frequency sensitive mechanism etc. of a shock absorber of an eighth embodiment according to the present invention. Specifically, it is an enlarged view of a part B of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [First embodiment] A shock absorber according to a first embodiment will be described below with reference to Figures 1 to 3. For ease of explanation, the upper side in Figures 1 to 10 will be referred to as "upper", and the lower side in Figures 1 to 10 will be referred to as "lower".

[0010] As shown in FIG. 1, the shock absorber 1 of the first embodiment is a twin-cylinder hydraulic shock absorber. The shock absorber 1 is used in a suspension device of a vehicle, specifically an automobile. The shock absorber 1 includes a cylinder 2 in which oil L is sealed as a working fluid. The cylinder 2 has an inner cylinder 3 and an outer cylinder 4. The inner cylinder 3 is cylindrical. The outer cylinder 4 is cylindrical with a bottom. The inner diameter of the outer cylinder 4 is larger than the outer diameter of the inner cylinder 3. The inner cylinder 3 is disposed radially inside the outer cylinder 4. The central axis of the inner cylinder 3 and the central axis of the outer cylinder 4 coincide with each other. A reservoir chamber 6 is formed between the inner cylinder 3 and the outer cylinder 4. The outer cylinder 4 has a body 11 and a bottom 12. The body 11 and the bottom 12 are integrally formed. The body 11 is cylindrical. The bottom 12 closes the lower part of the body 11. An attachment eye (not shown) is fixed to the outside of the bottom 12, opposite the body 11 in the axial direction.

[0011] The shock absorber 1 includes a piston 18. The piston 18 is inserted into the inner tube 3 of the cylinder 2. The piston 18 is slidably fitted into the inner tube 3 of the cylinder 2. The piston 18 divides the inner tube 3 into two chambers, an upper chamber 19 on one side and a lower chamber 20 on the other side. In the axial direction of the cylinder 2, the upper chamber 19 is located on the opposite side of the piston 18 from the bottom 12. In the axial direction of the cylinder 2, the lower chamber 20 is located on the bottom 12 side from the piston 18. In the upper chamber 19 and the lower chamber 20 of the inner tube 3, oil liquid L is sealed as a working fluid. In the reservoir chamber 6 between the inner tube 3 and the outer tube 4, oil liquid L and gas G are sealed as working fluids.

[0012] The shock absorber 1 includes a rod 21. A first end of the rod 21, which is one end in the axial direction, is disposed within the inner tube 3 of the cylinder 2. The first end of the rod 21 is fastened to the piston 18. A second end of the rod 21, which is opposite to the first end in the axial direction, protrudes from the cylinder 2 to the outside of the cylinder 2. The piston 18 is fixed to the rod 21. Therefore, the piston 18 and the rod 21 move together. In the shock absorber 1, a stroke in which the rod 21 moves in a direction to increase the amount of protrusion from the cylinder 2 is an extension stroke in which the overall length is extended. In the shock absorber 1, a stroke in which the rod 21 moves in a direction to decrease the amount of protrusion from the cylinder 2 is a compression stroke in which the overall length is contracted. In the shock absorber 1, the piston 18 moves toward the upper chamber 19 during the extension stroke. In the shock absorber 1, the piston 18 moves toward the lower chamber 20 during the compression stroke.

[0013] A rod guide 22 is fitted to the upper end opening side of the inner cylinder 3 and the upper end opening side of the outer cylinder 4. A seal member 23 is fitted to the outer cylinder 4 above the rod guide 22. Both the rod guide 22 and the seal member 23 are annular. The rod 21 slides along the axial direction relative to the rod guide 22 and the seal member 23. The rod 21 extends from inside the cylinder 2 to the outside of the cylinder 2 beyond the seal member 23.

[0014] The rod guide 22 restricts the rod 21 from moving radially relative to the inner tube 3 and the outer tube 4 of the cylinder 2. The rod 21 fits into the rod guide 22, and the piston 18 fits into the inner tube 3. This causes the central axis of the rod 21 to coincide with the central axis of the cylinder 2. The rod guide 22 supports the rod 21 so that it can move in the axial direction of the rod 21. The outer periphery of the seal member 23 is in close contact with the outer tube 4. The inner periphery of the seal member 23 is in close contact with the outer periphery of the rod 21. The rod 21 moves in the axial direction of the seal member 23 relative to the seal member 23. The seal member 23 prevents the oil liquid L in the inner tube 3 and the high-pressure gas G and oil liquid L in the reservoir chamber 6 from leaking out to the outside.

[0015] The outer periphery of the rod guide 22 is larger in diameter at the upper part than at the lower part. The smaller diameter lower part of the rod guide 22 fits into the inner periphery of the upper end of the inner cylinder 3. The larger diameter upper part of the rod guide 22 fits into the inner periphery of the upper part of the outer cylinder 4. A base valve 25 is installed on the bottom 12 of the outer cylinder 4. The base valve 25 is positioned radially relative to the outer cylinder 4. The inner periphery of the lower end of the inner cylinder 3 fits into the base valve 25. An upper end portion of the outer cylinder 4 is crimped toward the inside in the radial direction of the outer cylinder 4. The seal member 23 is fixed to the cylinder 2 by being sandwiched between this crimped portion and the rod guide 22.

[0016] The rod 21 has a main shaft portion 27 and an attachment shaft portion 28. The main shaft portion 27 and the attachment shaft portion 28 are both rod-shaped. The outer diameter of the mounting shaft portion 28 is smaller than the outer diameter of the main shaft portion 27. The mounting shaft portion 28 is disposed within the cylinder 2. The piston 18 is attached to the mounting shaft portion 28. The main shaft portion 27 has a shaft step portion 29. The shaft step portion 29 is provided at the end of the main shaft portion 27 on the mounting shaft portion 28 side in the axial direction. The shaft step portion 29 extends in a direction perpendicular to the central axis of the rod 21.

[0017] In the rod 21, a groove 30 is formed on the outer periphery of the mounting shaft portion 28. The groove 30 extends in the axial direction of the mounting shaft portion 28. The groove 30 is formed by cutting out the outer periphery of the mounting shaft portion 28 in a plane parallel to the central axis of the mounting shaft portion 28. The groove 30 is formed in two places spaced apart in the circumferential direction of the mounting shaft portion 28. A threaded portion 31 is formed on the outer periphery of the end of the mounting shaft portion 28 on the opposite side to the main shaft portion 27 from the groove 30 in the axial direction of the mounting shaft portion 28.

[0018] The shock absorber 1 is connected to the vehicle body with, for example, the portion of the rod 21 that protrudes from the cylinder 2 disposed at the top. In this case, the shock absorber 1 is connected to the vehicle wheel side with a mounting eye (not shown) provided on the cylinder 2 disposed at the bottom. Conversely, the shock absorber 1 may be connected to the vehicle body with the cylinder 2 side. In this case, the shock absorber 1 has the rod 21 connected to the wheel side.

[0019] As shown in FIG. 2, the piston 18 has a piston body 35 and a sliding member 36. The piston body 35 is formed by combining a divided body 33 and a divided body 34. The divided bodies 33 and 34 are both made of metal and are both annular. The divided bodies 33 and 34 have an inner diameter smaller than that of the divided body 34. The sliding member 36 is made of synthetic resin and is annular and band-like. The sliding member 36 is integrally attached to the outer circumferential surface of the piston body 35 in a state in which the divided bodies 33 and 34 are combined. As a result, the divided bodies 33 and 34 and the sliding member 36 are integrated to form the piston 18. The piston 18 is fitted to the mounting shaft portion 28 of the rod 21. The piston 18 slides relative to the inner cylinder 3 with the sliding member 36 in contact with the inner cylinder 3.

[0020] The piston body 35 is provided with a passage hole 37, a passage groove 38, a passage hole 39, and a passage groove 40. The passage hole 37 extends in the axial direction of the piston body 35. A plurality of the passage holes 37 are formed in the piston body 35 at intervals in the circumferential direction of the piston body 35 (only one is shown in FIG. 2 because the cross section is shown). The passage hole 39 extends in the axial direction of the piston body 35. A plurality of the passage holes 39 are formed in the piston body 35 at intervals in the circumferential direction of the piston body 35 (only one is shown in FIG. 2 because the cross section is shown). The piston body 35 is formed with the passage holes 37 and the passage holes 39 alternately at equal pitches in the circumferential direction of the piston body 35.

[0021] The passage groove 38 is formed in the divided body 34 of the piston body 35 in a ring shape in the circumferential direction of the divided body 34. The passage groove 38 is formed at the end of the divided body 34 opposite the divided body 33 in the axial direction. All the passage holes 37 open to the passage groove 38 at the end side in the axial direction of the piston body 35. The passage groove 40 is formed in the divided body 33 of the piston body 35 in a ring shape in the circumferential direction of the divided body 33. The passage groove 40 is formed at the end of the divided body 33 opposite the divided body 34 in the axial direction. All the passage holes 39 open to the passage groove 40 at the end side opposite the passage groove 38 in the axial direction of the piston body 35. In the piston 18, the inside of the multiple passage holes 37 and the inside of the passage groove 38 form a first passage 43. The first passage 43 penetrates the piston 18 in the axial direction of the piston 18. In the piston 18, the insides of the plurality of passage holes 39 and the insides of the passage grooves 40 form first passages 44. The first passages 44 penetrate the piston 18 in the axial direction of the piston 18. The first passages 43 and the first passages 44 are both provided in the piston 18.

[0022] A first damping force generating mechanism 41 is disposed in the first passage 43. The first damping force generating mechanism 41 opens and closes the first passage 43 to generate a damping force. The first damping force generating mechanism 41 is disposed on the lower chamber 20 side, which is one end side in the axial direction of the piston 18, and is attached to the rod 21. As a result, the first passage 43 becomes a passage through which the oil L as a working fluid moves from the upper chamber 19 to the lower chamber 20 by the movement of the piston 18 toward the upper chamber 19 side. In other words, the first passage 43 is a passage through which the oil L moves from the upper chamber 19, which is the upstream side, to the lower chamber 20, which is the downstream side, during the extension stroke. The first damping force generating mechanism 41 is an extension-side damping force generating mechanism that suppresses the flow of the oil L from the first passage 43 to the lower chamber 20, which occurs during the extension stroke, to generate a damping force.

[0023] A first damping force generating mechanism 42 is disposed in the first passage 44. The first damping force generating mechanism 42 opens and closes the first passage 44 to generate a damping force. The first damping force generating mechanism 42 is disposed on the upper chamber 19 side, which is the other end side in the axial direction of the piston 18, and is attached to the rod 21. As a result, the first passage 44 becomes a passage through which the oil L moves from the lower chamber 20 to the upper chamber 19 as the piston 18 moves toward the lower chamber 20. In other words, the first passage 44 is a passage through which the oil L moves from the lower chamber 20, which is the upstream side, to the upper chamber 19, which is the downstream side, during the compression stroke. The first damping force generating mechanism 42 is a compression-side damping force generating mechanism that suppresses the flow of the oil L from the first passage 44 to the upper chamber 19, which occurs during the compression stroke, to generate a damping force.

[0024] The piston body 35 has an insertion hole 45 formed in its radial center penetrating in the axial direction of the piston body 35. The mounting shaft portion 28 of the rod 21 is inserted through the insertion hole 45. The insertion hole 45 has a smaller diameter in the axial direction at a portion formed in the split body 33 on the upper chamber 19 side than at a portion formed in the split body 34 on the lower chamber 20 side. The piston body 35 fits onto the mounting shaft portion 28 of the rod 21 in the split body 33 having the smaller inner diameter.

[0025] A valve seat portion 48 is formed at the end of the piston body 35 on the axial side of the lower chamber 20. The valve seat portion 48 is annular. The valve seat portion 48 is disposed radially outward of the opening of the passage groove 38 on the lower chamber 20 side of the piston body 35. The valve seat portion 48 constitutes a part of the first damping force generating mechanism 41. A valve seat portion 49 is formed at the end of the piston body 35 on the upper chamber 19 side in the axial direction. The valve seat portion 49 is annular. The valve seat portion 49 is disposed radially outward of the opening of the passage groove 40 on the upper chamber 19 side of the piston body 35. The valve seat portion 49 constitutes a part of the first damping force generating mechanism 42. In the piston body 35, the openings of all the passage holes 39 facing the lower chamber 20 are arranged on the opposite side of the piston body 35 in the radial direction to the passage groove 38 of the valve seat portion 48. In the piston body 35, the openings of all the passage holes 37 facing the upper chamber 19 are arranged on the opposite side of the piston body 35 in the radial direction to the passage groove 40 of the valve seat portion 49.

[0026] On the valve seat portion 48 side in the axial direction of the piston 18, a plurality of (specifically, two) disks 50, a plurality of (specifically, five) disks 51, one pilot disk 52, one disk 53, one pilot case 55, one disk 56, a plurality of (specifically, six) disks 57, one disk 58, and one disk 59 are provided in this order from the piston 18 side in the axial direction of the piston 18. The disks 50, 51, 53, 56 to 59 and the pilot case 55 are all made of metal. The disks 50, 51, 53, 56 to 59 are all circular flat plates with holes of a constant thickness. The mounting shaft portion 28 of the rod 21 is fitted inside each of the disks 50, 51, 53, 56 to 59. The pilot disk 52 and the pilot case 55 are all annular. The mounting shaft portion 28 of the rod 21 is fitted inside both the pilot disk 52 and the pilot case 55 .

[0027] The pilot case 55 is cylindrical and has a bottom. A through hole 70 is formed in the center of the pilot case 55 in the radial direction. The through hole 70 passes through the pilot case 55 in the axial direction. The pilot case 55 has a bottom 71, an inner cylindrical portion 72, an outer cylindrical portion 73, an inner seat portion 74, and a valve seat portion 75.

[0028] The through hole 70 has a smaller diameter on the piston 18 side in the axial direction than on the opposite side to the piston 18, and the mounting shaft portion 28 of the rod 21 is fitted into this smaller diameter portion. The bottom portion 71 is in the shape of a disk having a hole. A passage hole 78 is formed in the bottom portion 71 radially outward of the through hole 70, penetrating the bottom portion 71 in the axial direction of the bottom portion 71. The inner cylindrical portion 72 is cylindrical and protrudes from the inner peripheral edge of the bottom portion 71 along the axial direction of the bottom portion 71 toward the piston 18 . The outer cylindrical portion 73 is cylindrical and protrudes from the outer peripheral edge of the bottom portion 71 along the axial direction of the bottom portion 71 on the same side as the inner cylindrical portion 72 . The passage hole 78 is disposed radially of the bottom 71 between the inner cylindrical portion 72 and the outer cylindrical portion 73 .

[0029] The inner seat portion 74 is annular, and protrudes slightly from the inner peripheral edge of the bottom portion 71 toward the axially opposite side of the inner cylindrical portion 72. The inner seat portion 74 is formed with a passage groove 79 that penetrates the inner seat portion 74 in the radial direction. The valve seat portion 75 is annular and has a larger diameter than the inner seat portion 74. The valve seat portion 75 protrudes from the bottom portion 71 along the axial direction of the bottom portion 71 on the same side as the inner seat portion 74, radially outward of the inner seat portion 74. The passage hole 78 is disposed between the inner seat portion 74 and the valve seat portion 75 in the radial direction of the bottom portion 71. The passage in the passage groove 79 of the inner seat portion 74 always communicates with the passage in the groove portion 30 of the rod 21 and the passage in the passage hole 78.

[0030] Of the multiple discs 50, the disc 50 on the piston 18 side in the axial direction abuts against a portion radially inward of the passage groove 38 of the piston 18. A notch 81 is formed in this disc 50. The passage in the notch 81 always communicates with the first passage 43 of the piston 18 and the passage in the groove portion 30 of the rod 21. Of the multiple discs 51, the disc 51 closest to the piston 18 in the axial direction abuts against the valve seat portion 48 of the piston 18. The multiple discs 51 open and close the opening of the first passage 43 formed in the piston 18 by moving away from and abutting against the valve seat portion 48.

[0031] The pilot disk 52 comprises a disk 85 and a seal member 86 . The disk 85 is made of metal and has a circular flat plate shape with holes. The mounting shaft portion 28 of the rod 21 is fitted inside the disk 85. Of the multiple disks 51, the disk 51 on the most opposite side to the piston 18 in the axial direction abuts against the disk 85 of the pilot disk 52. The seal member 86 is made of rubber and is bonded to the side of the disk 85 opposite to the piston 18 in the axial direction. The seal member 86 is fixed to the outer periphery of the disk 85 and has an annular shape. The seal member 86 is fitted liquid-tightly over the entire circumference of the inner periphery of the outer cylindrical portion 73 of the pilot case 55. The seal member 86 is axially slidable relative to the inner periphery of the outer cylindrical portion 73. The seal member 86 constantly seals the gap between the pilot disk 52 and the outer cylindrical portion 73.

[0032] The multiple discs 51 and the pilot disc 52 constitute a damping valve 91. When the damping valve 91 is released from the valve seat portion 48 of the piston 18 and opens, the damping valve 91 allows oil L from the first passage 43 to flow into the lower chamber 20 through a gap between the piston 18 and the outer cylindrical portion 73 of the pilot case 55. At that time, the damping valve 91 suppresses the flow of oil L between the valve seat portion 48. The damping valve 91 constitutes the first damping force generating mechanism 41 on the extension side. In the damping valve 91, a fixed orifice 92 is formed in the multiple discs 51, which communicates the first passage 43 with the lower chamber 20 even when the damping valve 91 is in contact with the valve seat portion 48. This fixed orifice 92 also constitutes the first damping force generating mechanism 41.

[0033] The disk 53 abuts against the disk 85 of the pilot disk 52. The disk 53 abuts against the inner cylindrical portion 72 of the pilot case 55. The disk 56 abuts against an inner seat portion 74 of the pilot case 55 . Of the multiple discs 57, the disc 57 on the disc 56 side in the axial direction can be seated on the valve seat portion 75. The multiple discs 57 configure a disc valve 99. The disc valve 99 can be seated on and removed from the valve seat portion 75. The disk 58 has an outer diameter smaller than the minimum outer diameter of the disk valve 99 . The disk 59 has an outer diameter larger than the outer diameter of the disk 58 .

[0034] A back pressure chamber 100 is formed between the bottom 71, inner cylindrical portion 72, and outer cylindrical portion 73 of the pilot case 55, the pilot disk 52, and the disk 53, between the bottom 71, inner seat portion 74, and valve seat portion 75 of the pilot case 55, the disk 56, and the disk valve 99, and inside the passage hole 78 of the pilot case 55. The back pressure chamber 100 applies pressure to the plurality of disks 51 in the direction of the piston 18 through the pilot disk 52. In other words, the back pressure chamber 100 applies internal pressure to the damping valve 91 in the valve closing direction in which the damping valve 91 is seated on the valve seat portion 48. The plurality of disks 51, the pilot disk 52, and the back pressure chamber 100 constitute a part of the first damping force generating mechanism 41. The back pressure chamber 100 is always in communication with the passage in the groove portion 30 of the rod 21 through a passage in the passage groove 79 of the pilot case 55.

[0035] The passage in the notch 81 of the disc 50, the passage in the groove portion 30 of the rod 21, and the passage in the passage groove 79 of the pilot case 55 form an introduction passage 102 that constantly connects the first passage 43 of the piston 18 and the back pressure chamber 100 and introduces oil L from the first passage 43 to the back pressure chamber 100. The extension side first damping force generating mechanism 41 introduces a portion of the flow of oil L into the back pressure chamber 100 via the introduction passage 102, and controls the opening of the damping valve 91 by the pressure of the back pressure chamber 100.

[0036] The disc valve 99 separates from the valve seat portion 75 to communicate between the back pressure chamber 100 and the lower chamber 20. At that time, the disc valve 99 restricts the flow of the oil L between the valve seat portion 75 and the disc valve 99. The disc valve 99 and the valve seat portion 75 constitute a second damping force generating mechanism 110. When the disc valve 99 is released from the valve seat portion 75, the second damping force generating mechanism 110 communicates the back pressure chamber 100 and the lower chamber 20. At that time, the second damping force generating mechanism 110 generates a damping force by suppressing the flow of oil L between the back pressure chamber 100 and the lower chamber 20. The second damping force generating mechanism 110 causes the oil L to flow from the upper chamber 19 to the lower chamber 20 via the first passage 43, the introduction passage 102, and the back pressure chamber 100 during the extension stroke. The second damping force generating mechanism 110 is an extension-side damping force generating mechanism that generates a damping force by suppressing the flow of oil L from the back pressure chamber 100 to the lower chamber 20 during the extension stroke.

[0037] On the valve seat portion 49 side of the piston 18 in the axial direction, there are provided, in this order from the piston 18 side in the axial direction of the piston 18, one disk 111, a plurality of (specifically, nine) disks 112, one disk 113, one disk 114, and one circular ring member 115. The disks 111-114 and the circular ring member 115 are all made of metal. The disks 111-114 and the circular ring member 115 are all in the form of a circular flat plate with holes of a constant thickness. The mounting shaft portion 28 of the rod 21 is fitted inside each of the disks 111-114 and the circular ring member 115.

[0038] The disk 111 abuts against a portion of the piston 18 that is radially inward of the passage groove 40 . Of the multiple discs 112, the disc 112 closest to the piston 18 in the axial direction abuts against the valve seat portion 49 of the piston 18. The multiple discs 112 open and close the opening of the first passage 44 formed in the piston 18 by moving away from and abutting against the valve seat portion 49. The multiple disks 112 constitute a disk valve 122. The disk valve 122 can be seated on and removed from the valve seat portion 49. The disk valve 122 can open the first passage 44 to the upper chamber 19 by being lifted off the valve seat portion 49. When the disk valve 122 is lifted off the valve seat portion 49 of the piston 18 and opened, the oil L from the first passage 44 flows into the upper chamber 19. At that time, the disk valve 122 suppresses the flow of the oil L between the valve seat portion 49. Therefore, the disk valve 122 suppresses the flow of the oil L from the lower chamber 20 to the upper chamber 19 via the first passage 44. The disk valve 122 and the valve seat portion 49 constitute the first damping force generating mechanism 42 on the compression side. The disk valve 122 is formed with a fixed orifice 123 that communicates the first passage 44 with the upper chamber 19 even when the disk valve 122 is in contact with the valve seat portion 49. The fixed orifice 123 also constitutes the first damping force generating mechanism 42 .

[0039] The disk 113 has an outer diameter smaller than the minimum outer diameter of the disk valve 122 . The outer diameter of disc 114 is larger than the outer diameter of disc 113. Disc 114 and circular member 115 abut against disc valve 122 when disc valve 122 deforms in the opening direction, suppressing deformation of disc valve 122 in the opening direction beyond a specified limit. Circular member 115 abuts against shaft step portion 29 of rod 21.

[0040] A frequency sensitive mechanism 130 is provided on the axial side of the disc 59 opposite to the disc 58. The frequency sensitive mechanism 130 varies the damping force according to the frequency of the axial movement of the piston 18 (hereinafter referred to as the piston frequency).

[0041] As shown in Fig. 3, the frequency sensitive mechanism 130 has one case member 131 on the side of the disk 59 in the axial direction. The frequency sensitive mechanism 130 has a plurality of (specifically, three) disks 132 having the same outer diameter and inner diameter, and a valve member 133 (first valve) on the opposite side of the disk 59 in the axial direction of the case member 131. The frequency sensitive mechanism 130 has, on the opposite side of the disk 59 in the axial direction of the disk 132 and the valve member 133, in order from the disk 132 and the valve member 133 side to the disk 59, a flexible member 135 (plate-shaped member), a disk 136, a stopper disk 137, a plurality of (specifically, two) stopper disks 138 having the same outer diameter and inner diameter, a plurality of (specifically, two) stopper disks 139 having the same outer diameter and inner diameter, and a plurality of (specifically, two) disks 140 having the same outer diameter and inner diameter. A circular ring member 141 is provided on the axially opposite side of disk 140 from stopper disk 139. Stopper disk 137, the plurality of stopper disks 138, and the plurality of stopper disks 139 form a stopper 142. The plurality of disks 140 form a support member 143.

[0042] The case member 131, the disks 132, 136, 140, the flexible member 135, the stopper disks 137-139, and the annular member 141 are all made of metal. The disks 132, 136, 140, the flexible member 135, the stopper disks 137-139, and the annular member 141 are all circular flat plates with holes of a certain thickness. In other words, the disks 132, 136, 140, the flexible member 135, the stopper disks 137-139, and the annular member 141 are all formed from annular plate-like members. The disks 132, 136, 140, the valve member 133, the flexible member 135, the stopper disks 137-139, and the annular member 141 are all disposed radially inward of the case member 131. The case member 131, the disks 132, 136, 140, the flexible member 135, the stopper disks 137-139, and the annular member 141 all have the mounting shaft portion 28 of the rod 21 fitted inside. As a result, the case member 131, the disks 132, 136, 140, the flexible member 135, the stopper disks 137-139, and the annular member 141 all have the central axis line aligned with that of the rod 21. The valve member 133 has the mounting shaft portion 28 of the rod 21 and the multiple disks 132 inserted into its inner periphery with radial gaps. In the frequency sensitive mechanism 130, the case member 131, the disks 132, 136, 140, the flexible member 135, and the stopper disks 137-139 form a valve case 145. The frequency sensitive mechanism 130 has the valve member 133 in the valve case 145.

[0043] The case member 131 is cylindrical and has a bottom. A through hole 155 is formed in the radial center of the case member 131, penetrating the case member 131 in the axial direction. As shown in Fig. 2, the through hole 155 has a smaller diameter on the piston 18 side in the axial direction than on the opposite side to the piston 18, and the mounting shaft portion 28 of the rod 21 is fitted into this smaller diameter portion.

[0044] As shown in FIG. 3, the case member 131 has a bottom portion 150, a protruding portion 151, a cylindrical portion 153, and a sheet portion 154. The bottom portion 150 is a circular plate having a hole. The width of the bottom portion 150 in the radial direction is constant over the entire circumference. A through hole 155 is formed in the bottom portion 150. The protruding portion 151 is annular. The protruding portion 151 protrudes from the inner peripheral edge of the bottom portion 150 in the axial direction of the bottom portion 150 toward the opposite side to the disk 59. A passage groove 158 is formed in the protruding portion 151, penetrating the protruding portion 151 in the radial direction. The passage in the passage groove 158 communicates with the passage in the groove portion 30 of the rod 21.

[0045] The cylindrical portion 153 is cylindrical with an inner diameter larger than the outer diameter of the protruding portion 151. The cylindrical portion 153 extends from the outer peripheral edge of the bottom portion 150 along the axial direction of the bottom portion 150 on the same side as the protruding portion 151. The cylindrical portion 153 has, on its inner peripheral side, a small diameter portion 161, a first inclined portion 162, a large diameter portion 163, a second inclined portion 164, and an open end portion 165, in that order from the bottom portion 150 side in the axial direction. The small diameter portion 161, the first inclined portion 162, the large diameter portion 163, the second inclined portion 164, and the open end portion 165 are aligned with each other along their central axes.

[0046] The small diameter portion 161 is located on the bottom portion 150 side in the axial direction of the cylindrical portion 153. The small diameter portion 161 has an inner peripheral surface that is cylindrical. The first inclined portion 162 extends in the opposite direction to the bottom portion 150 from an end portion of the small diameter portion 161 opposite to the bottom portion 150 in the axial direction. The inner diameter of the inner circumferential surface of the first inclined portion 162 becomes larger on the side opposite to the bottom portion 150 in the axial direction of the cylindrical portion 153. In other words, the first inclined portion 162 extends while expanding in diameter on the side opposite to the bottom portion 150 in the axial direction of the cylindrical portion 153. The first inclined portion 162 is tapered.

[0047] The large diameter portion 163 extends in the opposite direction to the bottom portion 150 from an end portion of the first inclined portion 162 opposite to the bottom portion 150 in the axial direction. The large diameter portion 163 has an inner peripheral surface that is cylindrical. The large diameter portion 163 is formed to have an inner diameter larger than that of the small diameter portion 161. The axial length of the large diameter portion 163 is shorter than the axial length of the small diameter portion 161. The first inclined portion 162 is provided between the small diameter portion 161 and the large diameter portion 163 in the axial direction of the tubular portion 153.

[0048] The second inclined portion 164 extends in the opposite direction to the bottom portion 150 from an end portion of the large diameter portion 163 opposite to the bottom portion 150 in the axial direction. The inner diameter of the inner circumferential surface of the second inclined portion 164 becomes larger toward the opposite side to the bottom portion 150 in the axial direction of the cylindrical portion 153. In other words, the second inclined portion 164 extends while expanding in diameter toward the opposite side to the bottom portion 150 in the axial direction of the cylindrical portion 153. In further words, the second inclined portion 164 is inclined so that the inner diameter becomes smaller toward the bottom portion 150 side in the axial direction of the cylindrical portion 153. The second inclined portion 164 is on the opposite side to the bottom portion 150 of the large diameter portion 163 in the axial direction of the cylindrical portion 153. The second inclined portion 164 has an R-chamfered shape.

[0049] The open end 165 extends in the opposite direction to the bottom 150 from the end of the second inclined portion 164 opposite to the bottom 150 in the axial direction. The open end 165 is at the end of the tubular portion 153 opposite to the bottom 150 in the axial direction. The open end 165 has an inner circumferential surface that is cylindrical. The open end 165 is formed with an inner diameter larger than that of the large diameter portion 163. The axial length of the open end 165 is shorter than the axial length of the large diameter portion 163.

[0050] As described above, the cylindrical portion 153 extends from the bottom 150 and includes a small diameter portion 161 located on the bottom 150 side and having a small inner diameter, and a large diameter portion 163 located on the opposite side of the bottom 150 from the small diameter portion 161 and having a larger inner diameter than the small diameter portion 161. The cylindrical portion 153 also includes a first inclined portion 162 between the small diameter portion 161 and the large diameter portion 163, which is inclined so as to connect the small diameter portion 161 and the large diameter portion 163. The cylindrical portion 153 also includes a second inclined portion 164 located on the opposite side of the bottom 150 from the large diameter portion 163, which is inclined so that the inner diameter becomes smaller toward the bottom 150 side.

[0051] The outer diameter of the disk 132 is constant over the entire circumference, and the radial width of the disk 132 is constant over the entire circumference. The outer diameter of the disk 132 is slightly smaller than the outer diameter of the end face of the protrusion 151 on the opposite side of the bottom portion 150 in the axial direction. The flexible member 135 has a constant outer diameter over its entire circumference, and a constant radial width over its entire circumference. The flexible member 135 has an outer diameter that is larger than the outer diameter of the disk 132. Disk 136 has a constant outer diameter and a constant radial width over its entire circumference. The outer diameter of disk 136 is smaller than the outer diameter of flexible member 135 and smaller than the outer diameter of disk 132.

[0052] The stopper disk 137 has a constant outer diameter over its entire circumference and a constant radial width over its entire circumference. The outer diameter of the stopper disk 137 is larger than the outer diameter of the disk 136 and is equal to the outer diameter of the flexible member 135. The stopper disc 138 has a constant outer diameter over the entire circumference and a constant radial width over the entire circumference. The outer diameter of the stopper disc 138 is larger than the outer diameter of the stopper disc 137. The stopper disc 139 has a constant outer diameter over its entire circumference and a constant radial width over its entire circumference. The outer diameter of the stopper disc 139 is larger than the outer diameter of the stopper disc 138.

[0053] The stopper 142 is composed of the stopper disks 137 to 139 as described above. In other words, the stopper 142 has a plurality of stopper disks 137 to 139 each formed of an annular plate-like member. The stopper disks 137 and 138 are formed such that the outer diameter of the stopper disk 138 provided on the opposite side to the flexible member 135 is larger than the outer diameter of the stopper disk 137 provided on the flexible member 135 side in the axial direction of the case member 131. The stopper disks 138 and 139 are formed such that the outer diameter of the stopper disk 139 provided on the opposite side to the flexible member 135 is larger than the outer diameter of the stopper disk 138 provided on the flexible member 135 side in the axial direction of the case member 131.

[0054] The outer diameter of the disk 140 constituting the support member 143 is constant over its entire circumference, and the radial width of the disk 140 is constant over its entire circumference. The outer diameter of the disk 140 is larger than the outer diameter of the stopper disk 139.

[0055] The disks 132, 136, 140, the valve member 133, the flexible member 135, the stopper disks 137-139, and the annular member 141 are all disposed radially inside the cylindrical portion 153. In other words, the outer diameters of the disks 132, 136, 140, the valve member 133, the flexible member 135, the stopper disks 137-139, and the annular member 141 are all smaller than the inner diameters of the portions where they overlap in the axial direction of the cylindrical portion 153. The disks 132, 136, 140, the valve member 133, the flexible member 135, and the stopper disks 137-139 are all disposed within the range of the cylindrical portion 153 in the axial direction of the cylindrical portion 153. A portion of the circular ring member 141 is positioned within the range of the cylindrical portion 153 in the axial direction of the cylindrical portion 153, and the remaining portion is positioned outside the range of the cylindrical portion 153 in the axial direction of the cylindrical portion 153.

[0056] The disks 132, 136, the stopper disks 137-139, and the flexible member 135 are disposed within the range of the small diameter portion 161 in the axial direction of the cylindrical portion 153. The disks 132, 136, the stopper disks 137-139, and the flexible member 135 all have an outer diameter smaller than the inner diameter of the small diameter portion 161.

[0057] Support member 143 consisting of multiple discs 140 is positioned to overlap small diameter portion 161, first inclined portion 162, and large diameter portion 163 in the axial direction of cylindrical portion 153. The outer diameter of discs 140, i.e., support member 143, is smaller than the inner diameter of small diameter portion 161. In the axial direction of cylindrical portion 153, first inclined portion 162 is provided within the range of support member 143 over its entire length.

[0058] The circular ring member 141 overlaps with the large diameter portion 163, the second inclined portion 164, and the open end 165 in the axial direction of the tubular portion 153. The outer diameter of the circular ring member 141 is smaller than the inner diameter of the large diameter portion 163. In the axial direction of the tubular portion 153, the second inclined portion 164 and the open end 165 are provided within the range of the circular ring member 141 over their entire length.

[0059] The seat portion 154 is annular. The seat portion 154 protrudes from a position between the protruding portion 151 and the cylindrical portion 153 in the radial direction of the bottom portion 150 to the same side as the protruding portion 151 and the cylindrical portion 153 along the axial direction of the bottom portion 150. A notch 168 is formed at the tip of the protruding side of the seat portion 154, penetrating the tip in the radial direction of the seat portion 154. A plurality of notches 168 are formed at intervals in the circumferential direction of the seat portion 154 in the seat portion 154. Thus, the tip of the protruding side of the seat portion 154 is intermittently cut out in the circumferential direction of the seat portion 154. The protruding height of the seat portion 154 from the bottom portion 150 in the axial direction of the bottom portion 150 is greater than the protruding height of the protruding portion 151 from the bottom portion 150.

[0060] The valve member 133 is made up of a valve disc 171 and an elastic seal member 172. The valve member 133 is disposed between the cylindrical portion 153 of the case member 131 and the multiple discs 132 in the radial direction. The valve disc 171 is made of metal. The valve disc 171 is a circular flat plate with holes of a constant thickness. The valve disc 171 has a constant outer diameter over the entire circumference and a constant radial width over the entire circumference. The mounting shaft portion 28 of the rod 21 and the multiple discs 132 are inserted into the inner circumference of the valve disc 171. The valve disc 171 is elastically deformable, that is, flexible. The valve disc 171 has an inner diameter that allows the multiple discs 132 to be arranged inside with radial gaps. In other words, the inner diameter of the valve disc 171 is larger than the outer diameters of the multiple discs 132. The outer diameter of the valve disc 171 is smaller than the inner diameter of the small diameter portion 161 of the cylindrical portion 153. The valve disc 171 is thinner than the total thickness of all the discs 132.

[0061] The elastic seal member 172 is made of rubber and has a circular shape. The elastic seal member 172 is bonded to the outer periphery of the valve disc 171. The elastic seal member 172 is baked onto the valve disc 171 and is provided integrally with the valve disc 171. The elastic seal member 172 has a seal portion 173 and a biasing portion 174 . The seal portion 173 is annular, and is fixed over the entire outer periphery of the outer periphery of the valve disc 171. The seal portion 173 protrudes from the valve disc 171 towards the bottom 150 of the case member 131 in the axial direction of the valve member 133.

[0062] The urging portion 174 is annular and protrudes from the valve disc 171 to the opposite side to the bottom portion 150 in the axial direction of the valve member 133. The urging portion 174 is fixed to the outer periphery of the valve disc 171. The seal portion 173 and the urging portion 174 are connected to each other on the outer periphery of the valve disc 171 to form an integral unit. The urging portion 174 has a smaller outer diameter and a larger inner diameter as it moves away from the valve disc 171 in the axial direction. As a result, the cross-sectional shape of the urging portion 174 on a plane including the central axis is a tapered mountain shape that becomes thinner as it moves away from the valve disc 171 in the axial direction. The urging portion 174 has a notch 175 formed at the tip of the protruding side, which penetrates the tip in the radial direction of the urging portion 174. The urging portion 174 has a plurality of notches 175 formed at intervals in the circumferential direction of the urging portion 174. Therefore, the tip end of the urging portion 174 on the protruding side is intermittently cut out in the circumferential direction of the urging portion 174.

[0063] As described above, there is a radial gap between the valve member 133 and the multiple disks 132. The valve member 133 is press-fitted at its seal portion 173 into the small diameter portion 161 of the cylindrical portion 153 of the case member 131. This press-fitting centers the valve member 133 so that it is coaxially disposed with respect to the case member 131, the multiple disks 132, and the rod 21. At that time, the seal portion 173 of the valve member 133 abuts against the small diameter portion 161 over the entire circumference with a radial interference.

[0064] The seal portion 173 has a cylindrical base portion 176 and an annular protrusion portion 177. The seal portion 173 is bonded to the valve disc 171 at the base portion 176 and is connected to the biasing portion 174. The protrusion portion 177 protrudes from an intermediate position in the axial direction of the base portion 176 to the outside in the radial direction of the base portion 176. When the elastic seal member 172, including the protrusion portion 177, is in a natural state without being deformed as a whole, the outer diameter of the base portion 176 is smaller than the inner diameter of the small diameter portion 161. Furthermore, when the elastic seal member 172 is in a natural state as a whole in this manner, the outer diameter of the protrusion portion 177 is larger than the inner diameter of the small diameter portion 161 and smaller than the inner diameter of the large diameter portion 163.

[0065] The valve member 133 is press-fitted at its seal portion 173 into the small diameter portion 161 of the cylindrical portion 153 of the case member 131. Then, the seal portion 173, mainly the protrusion portion 177, elastically deforms radially inward and comes into close contact with the small diameter portion 161 over the entire circumference. As a result, the seal portion 173 fits liquid-tightly into the small diameter portion 161 of the cylindrical portion 153 of the case member 131 over the entire circumference.

[0066] The seal portion 173 is slidable in the axial direction of the cylindrical portion 153 relative to the cylindrical portion 153. At that time, the seal portion 173 slides in the axial direction of the cylindrical portion 153 relative to the small diameter portion 161 while maintaining a state in which the protrusion portion 177 is in close contact with the small diameter portion 161 over the entire circumference. As a result, the protrusion portion 177 of the seal portion 173 of the elastic seal member 172 constantly seals the gap between the valve member 133 and the cylindrical portion 153. The cylindrical portion 153 is provided with a small diameter portion 161 in the sliding range of the protrusion portion 177 of the valve member 133. The cylindrical portion 153 is provided with a first inclined portion 162, a large diameter portion 163, a second inclined portion 164, and an opening end portion 165, which serve as a guide section for assembling the valve member 133, outside the small diameter portion 161, which is the sliding range of the protrusion portion 177. Of these, the large diameter portion 163, the second inclined portion 164 and the open end 165 all have inner diameters larger than the outer diameter of the protrusion portion 177 of the valve member 133 in its natural state. The seal portion 173 is located radially outward of the seat portion 154 of the case member 131. The valve member 133 has a valve disc 171 that seats on the seat portion 154.

[0067] The flexible member 135 has an outer diameter larger than the inner diameter of the valve member 133, i.e., the inner diameter of the valve disc 171. The flexible member 135 is disposed on the opposite side of the valve disc 171 from the bottom portion 150 in the axial direction, and is in pressure contact with the first support portion 178 on the inner periphery of the valve disc 171 over its entire periphery. This closes the gap between the flexible member 135 and the valve disc 171, i.e., the valve member 133.

[0068] As described above, the valve member 133 is centered relative to the valve case 145 by the seal portion 173 coming into contact with the cylindrical portion 153 over the entire circumference. In this state, the first support portion 178 on the inner circumferential side of the valve disc 171 of the valve member 133 is disposed between the protruding portion 151 and the flexible member 135 in the axial direction. The first support portion 178 has one side opposite to the bottom portion 150 in the axial direction in contact with the flexible member 135 and is supported by the flexible member 135. In other words, the valve member 133 has the first support portion 178 whose one radially inner side side is supported by the flexible member 135. The first support portion 178 is not clamped from both sides and is supported by the flexible member 135 only on one side. The first support portion 178 on the inner circumferential side of the valve disc 171 of the valve member 133 is movable between the protruding portion 151 and the flexible member 135 within the range of the entire axial length of the multiple (specifically, three) discs 132.

[0069] The valve member 133 has a second support portion 179, which is arranged radially outward from the first support portion 178 of the valve disc 171, in contact with and supported by the seat portion 154 at one side surface on the bottom portion 150 side in the axial direction. In other words, the valve member 133 has the second support portion 179, which is arranged radially outward from the first support portion 178 and has one side surface supported by the seat portion 154. The second support portion 179 is not clamped from both sides and is supported by the seat portion 154 on only one side. Therefore, the valve member 133 has a simply supported structure in which one surface side of a first support portion 178 of the valve disc 171 is supported by the flexible member 135, and the other surface side of a second support portion 179 radially outward of the first support portion 178 of the valve disc 171 is supported by the seat portion 154. In other words, the valve disc 171 is not clamped in the axial direction.

[0070] In the valve member 133, the biasing portion 174 is disposed on the opposite side of the bottom portion 150 in the axial direction of the valve member 133. A portion of the biasing portion 174 is disposed radially outward of the second support portion 179. The biasing portion 174 abuts against the support member 143 made of a plurality of disks 140 at a portion disposed radially outward of the second support portion 179. The biasing portion 174 biases the second support portion 179 side in the radial direction of the valve member 133 toward the seat portion 154 side in the axial direction of the valve member 133. The biasing portion 174 may be entirely disposed radially outward of the second support portion 179. That is, in the valve member 133, it is sufficient that at least a portion of the biasing portion 174 is disposed radially outward of the second support portion 179.

[0071] The valve member 133 is generally in the shape of a circular ring plate, and is generally elastically deformable, i.e., flexible. The valve member 133 is flexible such that the second support portion 179 moves away from the seat portion 154 while the first support portion 178 maintains a state of contact with the flexible member 135. When the valve member 133 is flexible in this manner, the valve member 133 is flexible such that the second support portion 179 moves toward the opposite side from the bottom portion 150 in the axial direction of the case member 131 relative to the first support portion 178. The outer diameter of the flexible member 135 is larger than the outer diameter of the disk 136 that abuts against the side surface opposite to the first support portion 178 in the axial direction. Therefore, the flexible member 135 is flexible in the axial direction of the case member 131 in a direction away from the bottom portion 150. The valve member 133 is flexible so that the second support portion 179 moves away from the seat portion 154 while the first support portion 178 remains in contact with the flexible member 135 .

[0072] The flexible member 135 is flexible together with the valve member 133. The flexible member 135 is thinner than the valve disc 171 of the valve member 133, and is less rigid than the valve disc 171, making it easier to bend. The flexible member 135 is flexible in the opposite direction to the bottom 150 due to movement and deformation in the axial direction of the valve member 133 toward the opposite side to the seat portion 154. The stopper 142 consisting of the stopper discs 137 to 139 suppresses the amount of bending of the flexible member 135 by the stopper disc 137 abutting against the bending flexible member 135. Here, the valve member 133 is flexible so as to move the second support portion 179 further toward the opposite side to the bottom 150 than the first support portion 178 in the axial direction of the case member 131, even if the bending of the flexible member 135 is suppressed by the stopper 142.

[0073] The multiple discs 140 have an outer diameter larger than the outer diameter of the stopper disc 139 and smaller than the inner diameter of the cylindrical portion 153. The inner circumferential side of the support member 143 made up of the multiple discs 140 abuts against the stopper disc 139 and the annular member 141, and the outer circumferential side abuts against the biasing portion 174 of the valve member 133. The support member 143 suppresses movement of the valve member 133 in the axial direction opposite to the bottom portion 150.

[0074] The seat portion 154 of the case member 131 supports the second support portion 179 of the valve disc 171 of the valve member 133 from one axial side. The flexible member 135 supports the first support portion 178, which is located more inward than the seat portion 154 of the valve disc 171, from the other axial side. The shortest axial distance between the seat portion 154 and the flexible member 135 is slightly smaller than the axial thickness of the valve disc 171. Therefore, the valve disc 171 is pressed against both the seat portion 154 and the flexible member 135 by its own elastic force in a slightly elastically deformed state.

[0075] The valve member 133 is provided in the case member 131 and divides the inside of the case member 131 into a first chamber 181 and a second chamber 182. The first chamber 181 is between the bottom 150 and the valve member 133 in the axial direction of the case member 131. In other words, the first chamber 181 is closer to the bottom 150 than the valve member 133 in the axial direction of the case member 131. The second chamber 182 is between the valve member 133 and the support member 143 in the axial direction of the case member 131. The support member 143 is provided in the second chamber 182 so as to form the second chamber 182. The second chamber 182 is on the opposite side to the bottom 150 than the valve member 133 in the axial direction of the case member 131, i.e., on the opening side of the case member 131.

[0076] The first chamber 181 and the second chamber 182 are both variable in volume, and the volume changes with the movement and deformation of the valve member 133. The first chamber 181 is constantly in communication with the passage in the groove portion 30 of the rod 21 through a passage in the passage groove 158 of the case member 131. The first chamber 181 is constantly in communication with the upper chamber 19 through the passage in the passage groove 158, the passage in the groove portion 30, the passage in the notch 81 shown in FIG. 2, and the first passage 43. The first chamber 181 is constantly in communication with the back pressure chamber 100 through the passage in the passage groove 158 shown in FIG. 3, the passage in the groove portion 30, and the passage in the passage groove 79 shown in FIG. 2. The second chamber 182 is constantly in communication with the lower chamber 20 through a passage portion 185 between the support member 143 and the cylindrical portion 153 of the case member 131.

[0077] During the extension stroke, oil L from the upper chamber 19 shown in Fig. 2 is introduced into the first chamber 181 via the first passage 43, the passage in the notch 81 of the disc 50, the passage in the groove portion 30 of the rod 21, and the passage in the passage groove 158 of the case member 131 shown in Fig. 3. Then, the valve disc 171 of the valve member 133 bends the flexible member 135 that abuts at the first support portion 178 in a direction away from the bottom portion 150 in the axial direction of the case member 131, i.e., in the direction of the stopper disc 137. At the same time, the valve disc 171 compresses and deforms the biasing portion 174 that abuts against the support member 143 in the axial direction of the case member 131 between the support member 143. At the same time, the valve disc 171 bends in a tapered manner, with the contact point with the flexible member 135 as a fulcrum, so that the second support portion 179 is further away from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178. In this way, the valve disc 171 bends, with the contact point with the flexible member 135 as a fulcrum, so that the second support portion 179 is further away from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178.

[0078] As the introduction of oil liquid L into first chamber 181 progresses further, bending of flexible member 135 in contact with valve disc 171 is restricted by abutting stopper disc 137 of stopper 142. Then, valve disc 171 bends in a tapered shape with the contact point with flexible member 135 as a fulcrum so that second support portion 179 is further separated from bottom 150 in the axial direction of case member 131 than first support portion 178, while further compressively deforming biasing portion 174 between support member 143 and valve disc 171 in the axial direction of case member 131.

[0079] Due to the above-mentioned movement and deformation of the valve disc 171, the valve member 133 increases the volume of the first chamber 181. Here, when the valve disc 171 deforms in this manner, the volume of the second chamber 182 decreases. At that time, the oil L in the second chamber 182 flows into the lower chamber 20 via the passage portion 185.

[0080] As shown in FIG. 2, the first passage 43, the passage in the notch 81, the passage in the groove portion 30 of the rod 21, the passage in the passage groove 158, the first chamber 181, the second chamber 182, and the passage portion 185 constitute a second passage 191 (passage). In the second passage 191, the first passage 43, the passage in the notch 81, the passage in the groove portion 30, the passage in the passage groove 158, and the first chamber 181 are always in communication with the upper chamber 19. In the second passage 191, the passage portion 185 and the second chamber 182 are always in communication with the lower chamber 20. The second passage 191 is a passage through which the oil L moves from the upper chamber 19, which is the upstream side, to the lower chamber 20, which is the downstream side, during the extension stroke. The second passage 191 is a passage through which the oil L moves from the lower chamber 20, which is the upstream side, to the upper chamber 19, which is the downstream side, during the contraction stroke. The frequency sensitive mechanism 130 has a valve member 133 provided in the second passage 191 .

[0081] The valve member 133 is capable of moving a first support portion 178 (shown in FIG. 3) on the inner circumferential side of the valve disc 171 toward the bottom portion 150 in the axial direction between the case member 131 and the flexible member 135. The valve member 133 is capable of moving a first support portion 178 of the valve disc 171 toward the bottom portion 150 in the axial direction while bending the flexible member 135 until the bending of the flexible member 135 is suppressed by the stopper 142. When the first support portion 178 of the valve disc 171 is in contact with the flexible member 135 over the entire circumference, the valve member 133 blocks the flow of the oil L between the first chamber 181 and the second chamber 182. When the first support portion 178 of the valve disc 171 is separated from the flexible member 135 in the axial direction, the valve member 133 allows the flow of the oil L between the second chamber 182 and the first chamber 181. The first support portion 178 of the valve disc 171 and the flexible member 135 form a check valve 193. The check valve 193 is provided in the second passage 191.

[0082] The check valve 193 restricts the flow of hydraulic fluid L from the first chamber 181 to the second chamber 182 through the second passage 191, while allowing the flow of hydraulic fluid L from the second chamber 182 to the first chamber 181 through the second passage 191. The check valve 193 blocks communication between the upper chamber 19 and the lower chamber 20 through the second passage 191 during an extension stroke in which the pressure in the upper chamber 19 becomes higher than the pressure in the lower chamber 20. The check valve 193 connects the lower chamber 20 to the upper chamber 19 through the second passage 191 during a compression stroke in which the pressure in the lower chamber 20 becomes higher than the pressure in the upper chamber 19. In this way, the second passage 191 connects the lower chamber 20 to the upper chamber 19 by opening the check valve 193.

[0083] 2, the rod 21 has the ring member 115, the disk 114, the disk 113, the plurality of disks 112, the disk 111, the piston 18, the plurality of disks 50, the plurality of disks 51, the pilot disk 52, the disk 53, the pilot case 55, the disk 56, the plurality of disks 57, the disk 58, the disk 59, the case member 131 and the plurality of disks 132 stacked in this order on the shaft step portion 29 with the mounting shaft portion 28 inserted inside each of them. At this time, the pilot case 55 fits the seal member 86 of the pilot disk 52 into the outer cylindrical portion 73.

[0084] 3, with the mounting shaft portion 28 and the multiple discs 132 inserted inside, the valve member 133 is placed on the seat portion 154 of the case member 131. At this time, the elastic seal member 172 of the valve member 133 is fitted into the cylindrical portion 153 of the case member 131. Furthermore, with the mounting shaft portion 28 inserted into the inside of each, the flexible member 135, the disk 136, the stopper disk 137, the multiple stopper disks 138, the multiple stopper disks 139, the multiple disks 140 and the circular member 141 are stacked in this order on the disk 132 and the valve disk 171 of the valve member 133.

[0085] As shown in FIG. 2, in a state where the parts from the circular member 115 to the circular member 141 are arranged on the rod 21 as described above, a nut 195 is screwed onto the threaded portion 31 of the mounting shaft portion 28 protruding from the circular member 141. As a result, the inner circumferential sides or the entire parts from the circular member 115 to the circular member 141 are sandwiched between the shaft step portion 29 of the rod 21 and the nut 195 and clamped in the axial direction. At that time, the valve member 133, including its inner circumferential side, is not clamped in the axial direction. In this state, as shown in FIG. 3, the first support portion 178 of the valve disc 171 abuts against the flexible member 135, the second support portion 179 abuts against the seat portion 154 of the case member 131, and the biasing portion 174 of the elastic seal member 172 abuts against the support member 143.

[0086] As shown in FIG. 1, the above-mentioned base valve 25 is provided between the bottom 12 of the outer tube 4 and the inner tube 3. The base valve 25 has a base valve member 221, a disk valve 222, a disk valve 223, and a mounting pin 224. The base valve 25 has the base valve member 221 placed on the bottom 12, and the base valve member 221 fitted into the inner tube 3. The base valve member 221 separates the lower chamber 20 and the reservoir chamber 6. The disk valve 222 is provided below the base valve member 221, that is, on the reservoir chamber 6 side. The disk valve 223 is provided above the base valve member 221, that is, on the lower chamber 20 side. The mounting pin 224 attaches the disk valve 222 and the disk valve 223 to the base valve member 221.

[0087] The base valve member 221 has an annular shape, and a mounting pin 224 is inserted through the center in the radial direction. The base valve member 221 is formed with a plurality of passage holes 225 and a plurality of passage holes 226. The plurality of passage holes 225 allow the oil L to flow between the lower chamber 20 and the reservoir chamber 6. The plurality of passage holes 226 are arranged outside the plurality of passage holes 225 in the radial direction of the base valve member 221. The plurality of passage holes 226 allow the oil L to flow between the lower chamber 20 and the reservoir chamber 6. The disk valve 222 on the reservoir chamber 6 side allows the oil L to flow from the lower chamber 20 to the reservoir chamber 6 via the passage hole 225. On the other hand, the disk valve 222 suppresses the flow of the oil L from the reservoir chamber 6 to the lower chamber 20 via the passage hole 225. The disc valve 223 allows the flow of oil L from the reservoir chamber 6 to the lower chamber 20 via the passage hole 226. On the other hand, the disc valve 223 restricts the flow of oil L from the lower chamber 20 to the reservoir chamber 6 via the passage hole 226.

[0088] The disc valve 222 and the base valve member 221 form a damping valve mechanism 227. The damping valve mechanism 227 opens during the compression stroke of the shock absorber 1 to allow oil L to flow from the lower chamber 20 to the reservoir chamber 6 and generate a damping force. The disc valve 223 and the base valve member 221 form a suction valve mechanism 228. The suction valve mechanism 228 opens during the extension stroke of the shock absorber 1 to allow oil L to flow from the reservoir chamber 6 into the lower chamber 20. The suction valve mechanism 228 mainly functions to allow oil L to flow from the reservoir chamber 6 to the lower chamber 20 without generating any damping force, so as to compensate for a shortage of oil caused by the extension of the rod 21 from the cylinder 2.

[0089] Next, the main operation of the shock absorber 1 will be described. "When it is assumed that the frequency sensitive mechanism 130 does not operate during the extension stroke, and only the first damping force generating mechanism 41 and the second damping force generating mechanism 110 on the extension side operate" In this case, when the moving speed of the piston 18 (hereinafter referred to as the piston speed) is slower than the first predetermined value, the oil L from the upper chamber 19 flows into the lower chamber 20 via the first passage 43 and the fixed orifice 92 of the first damping force generating mechanism 41 shown in FIG. 2. Thus, a damping force with an orifice characteristic (where the damping force is approximately proportional to the square of the piston speed) is generated. Therefore, when the piston speed is slower than the first predetermined value, the characteristic of the damping force with respect to the piston speed is that the rate of increase of the damping force with respect to an increase in the piston speed is relatively high.

[0090] When the piston speed is equal to or greater than the first predetermined value and less than the second predetermined value, the oil L from the upper chamber 19 passes through the first passage 43, the passage in the notch 81, the passage in the groove portion 30, the passage in the passage groove 79, the back pressure chamber 100, and flows between the disc valve 99 and the valve seat portion 75 into the lower chamber 20 while opening the disc valve 99 of the second damping force generating mechanism 110. Thus, a damping force with valve characteristics (the damping force is approximately proportional to the piston speed) is generated. Therefore, the characteristic of the damping force with respect to the piston speed when the piston speed is equal to or greater than the first predetermined value and less than the second predetermined value is that the rate of increase of the damping force with respect to an increase in the piston speed is lower than when the piston speed is less than the first predetermined value.

[0091] When the piston speed becomes faster than the second predetermined value, the relationship of the forces (hydraulic pressure) acting on the damping valve 91 of the first damping force generating mechanism 41 is such that the force in the opening direction applied from the first passage 43 becomes larger than the force in the closing direction applied from the back pressure chamber 100. Therefore, in this region, as the piston speed increases, the damping valve 91 opens away from the valve seat portion 48 of the piston 18. Therefore, the oil L from the upper chamber 19 flows from the first passage 43 to the lower chamber 20 through between the damping valve 91 and the valve seat portion 48 while opening the damping valve 91, in addition to the flow to the lower chamber 20 passing between the disc valve 99 and the valve seat portion 75 while opening the disc valve 99 as described above. Therefore, the increase rate of the damping force with respect to the increase in the piston speed when the piston speed is equal to or greater than the second predetermined value is lower than when the piston speed is equal to or greater than the first predetermined value and less than the second predetermined value.

[0092] "When it is assumed that the frequency sensitive mechanism 130 does not operate during the compression stroke and only the first damping force generating mechanism 42 on the compression side operates" In this case, when the piston speed is slower than the third predetermined value, the oil L from the lower chamber 20 flows into the upper chamber 19 via the first passage 44 and the fixed orifice 123 of the first damping force generating mechanism 42. This generates a damping force with orifice characteristics. Therefore, the characteristic of the damping force with respect to the piston speed when the piston speed is slower than the third predetermined value is that the rate of increase of the damping force with respect to an increase in the piston speed is relatively high.

[0093] When the piston speed becomes faster than the third predetermined value, the oil L introduced from the lower chamber 20 into the first passage 44 opens the disc valve 122 of the first damping force generating mechanism 42 and flows between the disc valve 122 and the valve seat portion 49 into the upper chamber 19. This generates a damping force with valve characteristics. For this reason, the characteristic of the damping force relative to the piston speed when the piston speed is equal to or greater than the third predetermined value is that the rate of increase of the damping force relative to an increase in the piston speed is lower than when the piston speed is less than the third predetermined value.

[0094] "When the frequency sensitive mechanism 130 acts during the extension stroke" In the first embodiment, the frequency sensitive mechanism 130 varies the damping force according to the piston frequency even when the piston speed is the same.

[0095] During the extension stroke, the oil L is introduced from the upper chamber 19 into the first chamber 181 of the frequency sensitive mechanism 130 through the first passage 43, the passage in the notch 81, the passage in the groove portion 30, and the passage in the passage groove 158. Then, the valve member 133, which was in contact with the flexible member 135, the seat portion 154, and the support member 143, has its valve disc 171 bend the flexible member 135, which it abuts against at the first support portion 178, in a direction away from the bottom portion 150 in the axial direction of the case member 131. At the same time, the valve disc 171 compresses and deforms the biasing portion 174, which abuts against the support member 143, in the axial direction of the case member 131 between the support member 143. At the same time, the valve disc 171 bends in a tapered shape with the contact point with the flexible member 135 as a fulcrum so that the second support portion 179 is farther away from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178. When the introduction of oil liquid L into first chamber 181 progresses further and flexible member 135 abuts against stopper 142 to restrict bending, valve disc 171 bends in a tapered manner, with the contact point with flexible member 135 as a fulcrum, so that second support portion 179 is further away from bottom 150 in the axial direction of case member 131 than first support portion 178, while further compressing and deforming biasing portion 174 in the axial direction of case member 131 between support member 143. The valve member 133 expands the volume of the first chamber 181 in the above manner, and introduces the oil L into the first chamber 181. At that time, the valve member 133 discharges the oil L from the second chamber 182 to the lower chamber 20 through the passage portion 185.

[0096] Here, in the extension stroke when the piston frequency is high, the stroke of the piston 18 is small. Therefore, the amount of oil L introduced from the upper chamber 19 to the first chamber 181 through the first passage 43, the passage in the notch 81, the passage in the groove portion 30, and the passage in the passage groove 158 is small. Therefore, although the valve member 133 deforms as described above, it does not deform to near its limit.

[0097] Therefore, during the extension stroke when the piston frequency is high, the valve member 133 of the frequency sensitive mechanism 130 moves and bends as described above while bending the bending member 135 at each extension stroke, thereby introducing the oil L from the upper chamber 19 into the first chamber 181. Then, the flow rate of the oil L flowing from the upper chamber 19 through the first passage 43, the passage in the notch 81, the passage in the groove portion 30, the passage in the passage groove 79, and the back pressure chamber 100 to the lower chamber 20 while opening the disc valve 99 of the second damping force generating mechanism 110 is reduced. In addition to this, the flow rate of the oil L flowing from the first passage 43 to the lower chamber 20 while opening the damping valve 91 of the first damping force generating mechanism 41 is also reduced. In addition, by introducing oil L from the upper chamber 19 into the first chamber 181, the pressure rise in the back pressure chamber 100 is suppressed compared to when the first chamber 181 is not present, and the damping valve 91 of the first damping force generating mechanism 41 is more likely to open. As a result, the damping force on the extension side becomes softer.

[0098] On the other hand, in the extension stroke when the piston frequency is low, the stroke of the piston 18 is large. Therefore, the amount of oil L introduced from the upper chamber 19 to the first chamber 181 through the first passage 43, the passage in the notch 81, the passage in the groove portion 30, and the passage in the passage groove 158 is large. Therefore, although the oil L flows from the upper chamber 19 to the first chamber 181 at the beginning of the stroke of the piston 18, the flexible member 135 and the valve member 133 are deformed to near their limits and do not deform any further thereafter. As a result, the oil L does not flow from the upper chamber 19 to the first chamber 181. As a result, the flow rate of the oil L flowing from the upper chamber 19 to the lower chamber 20 through the first passage 43, the passage in the notch 81, the passage in the groove portion 30, the passage in the passage groove 79, and the back pressure chamber 100 while opening the second damping force generating mechanism 110 does not decrease. In addition to this, the flow rate of the oil liquid L flowing from the first passage 43 to the lower chamber 20 does not decrease while the damping valve 91 of the first damping force generating mechanism 41 is open. In addition, because the oil liquid L is not introduced from the upper chamber 19 to the first chamber 181, the pressure in the back pressure chamber 100 increases, making it difficult for the damping valve 91 of the first damping force generating mechanism 41 to open. As a result, during the extension stroke when the piston frequency is low, the damping force becomes harder than when the piston frequency is high.

[0099] During the compression stroke, the pressure in the lower chamber 20 increases, but the valve disc 171 of the valve member 133 of the frequency sensitive mechanism 130 abuts against the seat portion 154 of the case member 131 at the second support portion 179 to suppress the expansion of the second chamber 182. Therefore, the amount of oil L introduced from the lower chamber 20 to the second chamber 182 through the passage portion 185 is suppressed. As a result, the flow rate of the oil L introduced from the lower chamber 20 to the first passage 44, passing through the first damping force generating mechanism 42, and flowing into the upper chamber 19 does not decrease. Therefore, the damping force becomes hard. During the compression stroke, when the piston speed increases and the pressure in the second chamber 182 becomes higher than the pressure in the first chamber 181 by a predetermined value or more, the first support portion 178 on the inner periphery side of the valve member 133 moves away from the flexible member 135. In other words, the check valve 193 opens. As a result, oil L flows from the lower chamber 20 to the upper chamber 19 via the passage portion 185, the second chamber 182, the check valve 193, the first chamber 181, the passage in the passage groove 158, the passage in the groove portion 30, the passage in the notch 81, and the first passage 43. In this manner, the check valve 193 opens, and the valve member 133 suppresses the pressure difference between the second chamber 182 side and the first chamber 181 side. Therefore, the valve member 133 is prevented from bending excessively.

[0100] The above-mentioned Patent Document 1 describes a shock absorber using a flexible disk as a valve. When using a flexible plate-like valve, it is required to improve the durability.

[0101] In the shock absorber 1 of the first embodiment, a flexible plate-like valve member 133 is provided in a second passage 191 that communicates between the upper chamber 19 on one side and the lower chamber 20 on the other side in the cylinder 2. The valve member 133 has a first support portion 178 that supports one side surface on the radial inner side, a second support portion 179 that is disposed radially outward of the valve member 133 relative to the first support portion 178 and supports one side surface, and a biasing portion 174 that is at least partially disposed radially outward of the valve member 133 relative to the second support portion 179 and biases the second support portion 179 side of the valve member 133. The shock absorber 1 includes a flexible member 135 that abuts against the first support portion 178 of the valve member 133 and is flexible together with the valve member 133. In this manner, the flexible member 135 in the shock absorber 1 that abuts against the first support portion 178 of the valve member 133 is flexible. Therefore, in the shock absorber 1, the amount of bending of the valve member 133 is suppressed by the amount of bending of the bending member 135 compared to when the first support part 178 is supported without bending. Thus, the shock absorber 1 can suppress excessive bending of the valve member 133 while ensuring the volume of the oil liquid L that can be received in the first chamber 181. Therefore, the shock absorber 1 can improve the durability of the valve member 133.

[0102] Here, when the valve member 133 functions as a partition member of the frequency sensitive mechanism 130, the initial ease of movement of the valve member 133 when the oil liquid L is received into the first chamber 181 affects the damping force when high-frequency vibration is input to the shock absorber 1. In the conventional structure, the portion supporting the first support portion 178 of the valve member 133 is fixed to the rod 21, but in the shock absorber 1 of this embodiment, it is a flexible member 135 that is flexible together with the valve member 133. Therefore, in the shock absorber 1, the flexible member 135 is movable in the axial direction relative to the rod 21, and the initial movement of the valve member 133 when the oil liquid L is received into the first chamber 181 can be made easier to move compared to the conventional structure.

[0103] Furthermore, in the shock absorber 1, the stopper 142 suppresses the amount of bending of the bending member 135, so that the durability of the bending member 135 can be improved. Furthermore, in the shock absorber 1, even if the deflection of the deflectable member 135 is restricted by the stopper 142, the valve member 133 is flexible, and therefore the deflection of the valve member 133 is not excessively restricted by the stopper 142 and the deflectable member 135. As a result, the volume of the oil liquid L that can be received in the first chamber 181 can be ensured. Furthermore, in the shock absorber 1, the flexible member 135 is formed from an annular plate-like member, so that an increase in cost due to the provision of the flexible member 135 can be suppressed.

[0104] [Second embodiment] Next, the second embodiment will be described with a focus on the differences from the first embodiment, mainly based on Fig. 4. Note that the same names and symbols are used for the parts common to the first embodiment. As shown in FIG. 4, a shock absorber 1A of the second embodiment has a frequency sensitive mechanism 130A which is partially different from the frequency sensitive mechanism 130 instead of the frequency sensitive mechanism 130.

[0105] Frequency sensitive mechanism 130A has valve case 145A which is partially different from valve case 145, instead of valve case 145. Valve case 145A has a different number of discs 132 from the number of discs 132 of valve case 145. Valve case 145A has a total thickness of all discs 132 which is equal to the total thickness of all discs 132 of valve case 145.

[0106] Moreover, valve case 145A has, instead of flexible member 135, flexible member 135A which differs from flexible member 135 in that it is thicker than flexible member 135. The thickness of flexible member 135A is equal to the thickness of valve disc 171. In valve case 145A, the position of the end face of flexible member 135A on the bottom 150 side in the axial direction of case member 131 is equal to the position of the end face of flexible member 135 on the bottom 150 side in the axial direction of case member 131 of valve case 145.

[0107] Further, the valve case 145A has a stopper 142A formed of a single member, instead of the disk 136, the stopper disk 137, the stopper disk 138, the stopper disk 139 and the support member 143 of the first embodiment. The stopper 142A is a circular plate with holes, and the radial width is constant over the entire circumference. The stopper 142A has a thick portion 241A, a thin portion 242A, and a connecting portion 243A. The thick portion 241A is located at the end of the stopper 142A on the inner periphery in the radial direction. The thin portion 242A is located at the end of the stopper 142A on the outer periphery in the radial direction. The connecting portion 243A is located between the thick portion 241A and the thin portion 242A in the radial direction of the stopper 142A. The thick portion 241A, the thin portion 242A, and the connecting portion 243A are aligned with each other at the end faces on one side in the axial direction of the case member 131.

[0108] The thick portion 241A has a constant radial width around the entire circumference. The mounting shaft portion 28 of the rod 21 fits into the thick portion 241A. This causes the stopper 142A to align with the central axis of the rod 21. The thick portion 241A abuts against the flexible member 135A and the annular member 141. The thick portion 241A has a radial width smaller than the radial width of the flexible member 135A.

[0109] In the axial direction of the stopper 142A, the thin wall portion 242A is thinner than the thick wall portion 241A. In the axial direction of the stopper 142A, the thin wall portion 242A is provided at the end opposite to the flexible member 135A. The thin wall portion 242A has a constant outer diameter over the entire circumference, and a constant radial width over the entire circumference. The outer diameter of the thin wall portion 242A is equal to the outer diameter of the support member 143 of the first embodiment. The thickness of the thin wall portion 242A is equal to the thickness of the support member 143 of the first embodiment. In the valve case 145A, the position of the end face of the thin wall portion 242A on the bottom 150 side in the axial direction of the case member 131 is equal to the position of the end face of the support member 143 on the bottom 150 side in the axial direction of the case member 131 of the valve case 145.

[0110] The connecting portion 243A has an inclined portion 245A on the side of the flexible member 135A in the axial direction of the stopper 142A. The inclined portion 245A has an outer diameter that becomes larger as it moves away from the flexible member 135A in the axial direction of the stopper 142A. In other words, the inclined portion 245A has an outer diameter that becomes larger as it approaches the thin-walled portion 242A in the axial direction of the stopper 142A. In further words, the inclined portion 245A is formed so that the outer diameter of the portion opposite the flexible member 135A is larger than the outer diameter of the portion on the flexible member 135A side in the axial direction of the stopper 142A. The inclined portion 245A has a curved end on the flexible member 135A side in the axial direction, and a tapered middle portion and an end opposite the flexible member 135A in the axial direction.

[0111] The valve member 133 is supported by the flexible member 135A with one side surface of the first support portion 178 opposite to the bottom portion 150 in the axial direction abutting against the flexible member 135A. The valve member 133 is supported by the seat portion 154 with one side surface of the second support portion 179 facing the bottom portion 150 in the axial direction abutting against the seat portion 154. The valve member 133 is supported by the thin-walled portion 242A with the biasing portion 174 abutting against the thin-walled portion 242A of the stopper 142A at a portion disposed radially outward from the second support portion 179. The thin-walled portion 242A suppresses movement of the valve member 133 in the axial direction in the opposite direction to the bottom portion 150 and the seat portion 154.

[0112] The outer diameter of the flexible member 135A is larger than the diameter of the thick portion 241A that abuts against the side surface opposite the first support portion 178 in the axial direction. Thus, the flexible member 135A is capable of bending in the axial direction in a direction away from the bottom portion 150. The valve member 133 is capable of bending such that the second support portion 179 moves away from the seat portion 154 while maintaining a state in which the first support portion 178 abuts against the flexible member 135A. When bending in this manner, the valve member 133 bends such that the second support portion 179 moves toward the opposite side from the bottom portion 150 relative to the first support portion 178 in the axial direction of the case member 131.

[0113] The flexible member 135A is flexible together with the valve member 133. The flexible member 135A is flexible in the opposite direction to the bottom portion 150 due to movement and deformation of the valve member 133 in the axial direction opposite to the seat portion 154. The stopper 142A abuts against the flexible member 135A thus flexible, thereby suppressing the amount of bending of the flexible member 135A. Here, even if the bending of the flexible member 135A is suppressed by the stopper 142A, the valve member 133 is flexible so as to move the second support portion 179 further toward the opposite side to the bottom portion 150 than the first support portion 178 in the axial direction of the case member 131.

[0114] In the shock absorber 1A of the second embodiment, during the extension stroke, the oil L from the upper chamber 19 (see FIG. 2) is introduced into the first chamber 181 through the first passage 43 (see FIG. 2), the passage in the notch 81 (see FIG. 2) of the disc 50, the passage in the groove portion 30 of the rod 21 shown in FIG. 4, and the passage in the passage groove 158 of the case member 131. Then, the valve disc 171 of the valve member 133 bends the flexible member 135A that abuts on the first support portion 178 in a direction away from the bottom portion 150 in the axial direction of the case member 131. At the same time, the valve disc 171 compresses and deforms the biasing portion 174 that abuts on the thin portion 242A of the stopper 142A in the axial direction of the case member 131 between the thin portion 242A. At the same time, the valve disc 171 bends in a tapered manner, with the contact point with the flexible member 135A as a fulcrum, so that the second support portion 179 is farther from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178. In this way, the valve disc 171 bends, with the contact point with the flexible member 135A as a fulcrum, so that the second support portion 179 is farther from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178.

[0115] As the oil liquid L is further introduced into the first chamber 181, the flexible member 135A comes into contact with the inclined portion 245A of the stopper 142A, and the deflection is restricted. Then, the valve disc 171 deflects in a tapered shape with the contact point with the flexible member 135A as a fulcrum so that the second support portion 179 is further separated from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178, while the biasing portion 174 is further compressed and deformed in the axial direction of the case member 131 between the thin-walled portion 242A.

[0116] By the movement and deformation of the valve disc 171 as described above, the valve member 133 increases the volume of the first chamber 181. Here, the first support portion 178 of the valve disc 171 and the flexible member 135A form a check valve 193A that operates similarly to the check valve 193 by closing when they come into contact with each other and opening when they move away from each other.

[0117] The shock absorber 1A of the second embodiment includes a flexible member 135A that abuts against the first support portion 178 of the valve member 133 and is flexible together with the valve member 133. Therefore, similar to the shock absorber 1, the shock absorber 1A can improve the durability of the valve member 133 while ensuring the volume of the oil liquid L that can be received in the first chamber 181. At the same time, the shock absorber 1A can facilitate the initial movement of the valve member 133 when the oil liquid L is received in the first chamber 181. Furthermore, in the shock absorber 1A, the stopper 142A suppresses the amount of bending of the bending member 135A, so that, similarly to the shock absorber 1, the durability of the bending member 135A can be improved.

[0118] In addition, in the shock absorber 1A, the valve member 133 can bend even when the bending of the bending member 135A is suppressed by the stopper 142A, so that, like the shock absorber 1, the volume of oil liquid L that can be received in the first chamber 181 can be further secured. Furthermore, in the shock absorber 1A, the flexible member 135A is formed of an annular plate-shaped member, so similarly to the shock absorber 1, an increase in costs due to the provision of the flexible member 135A can be suppressed. Furthermore, in the shock absorber 1A, the stopper 142A, which is made of a single member, suppresses the bending of the bending member 135A and supports the biasing portion 174 of the valve member 133, so that the number of parts can be reduced and management costs can be suppressed.

[0119] [Third embodiment] Next, the third embodiment will be described with a focus on the differences from the first embodiment, mainly with reference to Fig. 5. The same parts as those in the first embodiment will be designated by the same names and reference numerals. As shown in FIG. 5, a shock absorber 1B of the third embodiment has a frequency sensitive mechanism 130B which is partially different from the frequency sensitive mechanism 130 instead of the frequency sensitive mechanism 130.

[0120] Frequency sensitive mechanism 130B has valve case 145B which is partially different from valve case 145, instead of valve case 145. Valve case 145B has a different number of discs 132 from the number of discs 132 of valve case 145. Valve case 145B has a total thickness of all discs 132 which is equal to the total thickness of all discs 132 of valve case 145.

[0121] The valve case 145B has a flexible member 135B (plate-shaped member) instead of the flexible member 135. The flexible member 135B is made of a plurality of (specifically, two) annular members 251B, 252B. The annular member 251B is a component similar to the flexible member 135. The annular member 252B is made of metal. The annular member 252B is in the shape of a disk with holes. The annular member 252B has a constant outer diameter around the entire circumference, and a constant radial width around the entire circumference.

[0122] The annular member 251B is located closer to the bottom 150 than the annular member 252B in the axial direction of the case member 131, i.e., closer to the valve disc 171. The outer diameter of the annular member 252B is smaller than the outer diameter of the annular member 251B. In other words, the multiple annular members 251B, 252B are formed such that the outer diameter of the annular member 252B provided on the opposite side to the valve member 133 is smaller than the outer diameter of the annular member 251B provided on the valve member 133 side. The thickness of the annular member 251B is greater than the thickness of the annular member 252B. The outer diameter of the annular member 252B is greater than the outer diameter of the disc 136.

[0123] The mounting shaft portion 28 of the rod 21 is fitted inside each of the annular members 251B and 252B. As a result, the central axis of each of the annular members 251B and 252B coincides with that of the rod 21. Each of the annular members 251B and 252B is elastically deformable, i.e., flexible. The annular members 251B and 252B abut against each other in the axial direction. The flexible member 135B having the annular members 251B and 252B is elastically deformable, i.e., flexible.

[0124] The valve case 145B has a stopper 142B, which is partially different from the stopper 142, instead of the stopper 142. The stopper 142B has a plurality of stopper disks 138B (specifically, two) having the same outer diameter and inner diameter instead of the stopper disks 138, 139. The stopper disk 138B is different from the stopper disks 138, 139 in that the outer diameter of the stopper disk 138B is different from that of the stopper disks 138, 139. The outer diameter of the stopper disk 138B is larger than that of the stopper disk 137 and smaller than that of the disk 140. In the valve case 145B, the position of the end face of the support member 143 on the bottom 150 side in the axial direction of the case member 131 is the same as the position of the end face of the support member 143 on the bottom 150 side in the axial direction of the case member 131 of the valve case 145.

[0125] The valve member 133 is supported by the flexible member 135B with one side surface of the first support portion 178 opposite to the bottom portion 150 in the axial direction abutting against the annular member 251B of the flexible member 135B. At that time, the first support portion 178 is aligned radially with both the annular members 251B and 252B. Similar to the valve member 133 of the frequency sensitive mechanism 130, the valve member 133 of the frequency sensitive mechanism 130B has a second support portion 179 supported by the seat portion 154 and a biasing portion 174 supported by the support member 143.

[0126] In the flexible member 135B, the outer diameters of the annular members 251B, 252B are both larger than the outer diameter of the disk 136. The valve member 133 is capable of bending such that the second support portion 179 moves away from the seat portion 154 while maintaining the state in which the first support portion 178 abuts against the flexible member 135B. When bending in this manner, the valve member 133 bends such that the second support portion 179 moves further away from the bottom portion 150 than the first support portion 178 in the axial direction of the case member 131.

[0127] The flexible member 135B is flexible together with the valve member 133. The flexible member 135B is flexible in the opposite direction to the bottom portion 150 due to movement and deformation of the valve member 133 in the axial direction opposite to the seat portion 154. The stopper 142B having the stopper disks 137, 138B suppresses the amount of bending of the flexible member 135B by the stopper disk 137 abutting against the flexible member 135B thus bending. Here, the valve member 133 is flexible in the axial direction of the case member 131 so as to move the second support portion 179 further toward the opposite side to the bottom portion 150 than the first support portion 178, even if the bending of the flexible member 135B is suppressed by the stopper 142B.

[0128] In the shock absorber 1B of the third embodiment, during the extension stroke, the oil L from the upper chamber 19 (see FIG. 2) is introduced into the first chamber 181 through the first passage 43 (see FIG. 2), the passage in the notch 81 (see FIG. 2) of the disc 50, the passage in the groove portion 30 of the rod 21 shown in FIG. 5, and the passage in the passage groove 158 of the case member 131. Then, the valve disc 171 of the valve member 133 bends the bending member 135B that abuts on the first support portion 178 in a direction away from the bottom portion 150 in the axial direction of the case member 131. At that time, the valve disc 171 bends both the annular members 251B and 252B. At the same time, the valve disc 171 compresses and deforms the biasing portion 174 that abuts on the support member 143 in the axial direction of the case member 131 between the support member 143. At the same time, the valve disc 171 bends in a tapered manner, with the contact point with the flexible member 135B as a fulcrum, so that the second support portion 179 is further away from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178. In this way, the valve disc 171 bends, with the contact point with the flexible member 135B as a fulcrum, so that the second support portion 179 is further away from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178.

[0129] As the introduction of oil liquid L into first chamber 181 progresses further, annular member 252B of flexible member 135B comes into contact with stopper disc 137, restricting the bending. Then, valve disc 171 bends annular member 251B in a direction away from bottom 150 in the axial direction of case member 131. At the same time, valve disc 171 bends in a tapered shape with the contact point with flexible member 135B as a fulcrum so as to move second support portion 179 further away from bottom 150 in the axial direction of case member 131 than first support portion 178, while further compressively deforming biasing portion 174 between support member 143 in the axial direction of case member 131.

[0130] As the introduction of oil liquid L into first chamber 181 progresses further, annular member 251B comes into contact with stopper disc 137, restricting the deflection. Then, valve disc 171 deflects in a tapered shape with the contact point with deflecting member 135B as a fulcrum so that second support portion 179 is further separated from bottom portion 150 in the axial direction of case member 131 than first support portion 178, while further compressively deforming biasing portion 174 between support member 143 and valve disc 171 in the axial direction of case member 131.

[0131] By the movement and deformation of the valve disc 171 as described above, the valve member 133 increases the volume of the first chamber 181. Here, the first support portion 178 of the valve disc 171 and the annular member 251B of the flexible member 135B form a check valve 193B that operates similarly to the check valve 193 by closing when they come into contact with each other and opening when they move away from each other.

[0132] The shock absorber 1B of the third embodiment includes a flexible member 135B that abuts against the first support portion 178 of the valve member 133 and is flexible together with the valve member 133. Therefore, similar to the shock absorber 1, the shock absorber 1B can improve the durability of the valve member 133 while ensuring the volume of oil liquid L that can be received in the first chamber 181. At the same time, the shock absorber 1B can facilitate the initial movement of the valve member 133 when the oil liquid L is received in the first chamber 181. Furthermore, in the shock absorber 1B, the stopper 142B suppresses the amount of bending of the bending member 135B, so that, similarly to the shock absorber 1, the durability of the bending member 135B can be improved.

[0133] In addition, in shock absorber 1B, valve member 133 can bend even when the bending of bending member 135B is suppressed by stopper 142B, so that, like shock absorber 1, the volume of oil liquid L that can be received in first chamber 181 can be further secured. Furthermore, in the shock absorber 1B, the flexible member 135B is formed of an annular plate-shaped member, so similarly to the shock absorber 1, an increase in cost due to the provision of the flexible member 135B can be suppressed.

[0134] In addition, in the shock absorber 1B, the flexible member 135B has a plurality of annular members 251B, 252B. These annular members 251B, 252B are formed so that the outer diameter of the annular member 252B provided on the opposite side to the valve member 133 is smaller than the outer diameter of the annular member 251B provided on the valve member 133 side. This makes it possible to change the spring constant, i.e., the bending characteristics, of the flexible member 135B.

[0135] [Fourth embodiment] Next, the fourth embodiment will be described with a focus on the differences from the third embodiment, mainly with reference to Fig. 6. Note that the same names and symbols are used for the parts common to the third embodiment. As shown in FIG. 6, a shock absorber 1C of the fourth embodiment has a frequency sensitive mechanism 130C, which is partially different from the frequency sensitive mechanism 130B, instead of the frequency sensitive mechanism 130.

[0136] The frequency sensitive mechanism 130C has a valve case 145C which is partially different from the valve case 145B in place of the valve case 145B. The valve case 145C has a flexible member 135C (plate-shaped member) instead of the flexible member 135B. The flexible member 135C differs from the annular member 251B of the flexible member 135B in that the outer diameter of the flexible member 135C is larger than the outer diameter of the annular member 251B. The flexible member 135C does not have the annular member 252B.

[0137] The valve case 145C has a stopper 142C that is partially different from the stopper 142B in place of the stopper 142B. The stopper 142C has a plurality of (specifically, three) plate-shaped stopper members 261C, 262C, and 263C in place of the stopper disk 137 and one of the stopper disks 138B. The plate-shaped stopper members 261C, 262C, and 263C are all made of metal. The plate-shaped stopper members 261C, 262C, and 263C are all made of annular plate-shaped members.

[0138] The plate-shaped stopper members 261C, 262C, and 263C are all circular flat plates with holes of a constant thickness. The plate-shaped stopper members 261C, 262C, and 263C all have a constant outer diameter over the entire circumference, and a constant radial width over the entire circumference. The plate-shaped stopper members 261C, 262C, and 263C all have the mounting shaft portion 28 fitted inside. As a result, the plate-shaped stopper members 261C, 262C, and 263C all have a central axis that is aligned with the rod 21.

[0139] The plate-shaped stopper member 261C is located closer to the bottom 150, that is, closer to the valve disc 171, than the plate-shaped stopper member 262C in the axial direction of the case member 131. The plate-shaped stopper member 261C has an outer diameter equal to the outer diameter of the flexible member 135C. The plate-shaped stopper member 262C has an outer diameter smaller than that of the plate-shaped stopper member 261 C. The plate-shaped stopper member 262C is located on the opposite side to the valve disc 171 than the plate-shaped stopper member 261C in the axial direction of the case member 131. The outer diameter of the plate-shaped stopper member 263C is smaller than the outer diameter of the plate-shaped stopper member 262C. The plate-shaped stopper member 263C is located on the opposite side of the plate-shaped stopper member 262C from the valve disc 171 in the axial direction of the case member 131. Between the plate-shaped stopper member 263C and the disc 140 in the axial direction of the case member 131, one stopper disc 138B is provided.

[0140] As a result, the plurality of plate-shaped stopper members 261C, 262C are formed such that the outer diameter of the plate-shaped stopper member 262C provided on the opposite side to the valve member 133 is smaller than the outer diameter of the plate-shaped stopper member 261C provided on the valve member 133 side. Also, the plurality of plate-shaped stopper members 262C, 263C are formed such that the outer diameter of the plate-shaped stopper member 263C provided on the opposite side to the valve member 133 is smaller than the outer diameter of the plate-shaped stopper member 262C provided on the valve member 133 side.

[0141] The multiple plate-shaped stopper members 261C, 262C have the same thickness, which is thinner than the thickness of the plate-shaped stopper member 263C. In the stopper 142C having the plate-shaped stopper members 261C, 262C, 263C, the plate-shaped stopper members 261C, 262C are elastically deformable, that is, flexible. In the valve case 145C, the position of the end face of the support member 143 on the bottom 150 side in the axial direction of the case member 131 is equivalent to the position of the end face of the support member 143 on the bottom 150 side in the axial direction of the case member 131 of the valve case 145B.

[0142] The valve member 133 is supported by the flexible member 135C, with one side surface of the first support portion 178 opposite the bottom portion 150 in the axial direction being in contact with the flexible member 135C. Valve member 133 of frequency sensitive mechanism 130C has second support portion 179 supported by seat portion 154 and biasing portion 174 supported by support member 143, similar to valve member 133 of frequency sensitive mechanism 130B.

[0143] The outer diameter of the flexible member 135C is larger than the outer diameter of the annular member 251B. The valve member 133 is flexible such that the second support portion 179 moves away from the seat portion 154 while the first support portion 178 maintains a state of abutment with the flexible member 135C. When the valve member 133 flexes in this manner, the valve member 133 flexes such that the second support portion 179 moves toward the opposite side from the bottom portion 150 in the axial direction of the case member 131 relative to the first support portion 178.

[0144] The flexible member 135C is flexible together with the valve member 133. The flexible member 135C is flexible in the opposite direction to the bottom portion 150 due to movement and deformation of the valve member 133 in the axial direction opposite to the seat portion 154. The stopper 142C abuts against the flexible member 135C thus flexible, thereby suppressing the amount of bending of the flexible member 135C. Here, even if the bending of the flexible member 135C is suppressed by the stopper 142C, the valve member 133 is flexible so as to move the second support portion 179 further away from the bottom portion 150 than the first support portion 178 in the axial direction of the case member 131.

[0145] In the shock absorber 1C of the fourth embodiment, during the extension stroke, the oil L from the upper chamber 19 (see FIG. 2) is introduced into the first chamber 181 through the first passage 43 (see FIG. 2), the passage in the notch 81 (see FIG. 2) of the disc 50, the passage in the groove portion 30 of the rod 21 shown in FIG. 6, and the passage in the passage groove 158 of the case member 131. Then, the valve disc 171 of the valve member 133 bends the flexible member 135C that abuts on the first support portion 178 in a direction away from the bottom portion 150 in the axial direction of the case member 131. At the same time, the valve disc 171 compresses and deforms the biasing portion 174 that abuts on the support member 143 in the axial direction of the case member 131 between the support member 143. At the same time, the valve disc 171 bends in a tapered manner, with the contact point with the flexible member 135C as a fulcrum, so that the second support portion 179 is further away from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178. In this way, the valve disc 171 bends, with the contact point with the flexible member 135C as a fulcrum, so that the second support portion 179 is further away from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178.

[0146] As the introduction of oil liquid L into first chamber 181 progresses further, flexible member 135C comes into contact with plate-shaped stopper member 261C of stopper 142C, and the deflection is suppressed by plate-shaped stopper member 261C. Then, valve disc 171 deflects in a tapered shape with the contact point with flexible member 135C as a fulcrum so that second support portion 179 is further separated from bottom portion 150 in the axial direction of case member 131 than first support portion 178, while further compressively deforming biasing portion 174 between support member 143 and valve disc 171 in the axial direction of case member 131. At that time, plate-shaped stopper member 261C also deflects together with flexible member 135C.

[0147] When the valve disc 171 bends in a tapered manner with the contact point with the flexible member 135C as a fulcrum so that the second support portion 179 is further away from the bottom 150 in the axial direction of the case member 131 than the first support portion 178, both the plate-shaped stopper members 261C and 262C bend together with the flexible member 135C.

[0148] By the movement and deformation of the valve disc 171 as described above, the valve member 133 increases the volume of the first chamber 181. Here, the first support portion 178 of the valve disc 171 and the flexible member 135C form a check valve 193C that operates similarly to the check valve 193 by closing when they come into contact with each other and opening when they move away from each other.

[0149] The shock absorber 1C of the fourth embodiment includes a flexible member 135C that abuts against the first support portion 178 of the valve member 133 and is flexible together with the valve member 133. Therefore, similar to the shock absorber 1, the shock absorber 1C can improve the durability of the valve member 133 while ensuring the volume of the oil liquid L that can be received in the first chamber 181. At the same time, the shock absorber 1C can facilitate the initial movement of the valve member 133 when the oil liquid L is received in the first chamber 181. Furthermore, in the shock absorber 1C, the stopper 142C suppresses the amount of bending of the bending member 135C, so that, similarly to the shock absorber 1, the durability of the bending member 135C can be improved.

[0150] In addition, in the shock absorber 1C, the valve member 133 can bend even when the bending of the bending member 135C is suppressed by the stopper 142C, so that, like the shock absorber 1, the volume of oil liquid L that can be received in the first chamber 181 can be further secured. Furthermore, in the shock absorber 1C, the flexible member 135C is formed of an annular plate-shaped member, so similarly to the shock absorber 1, an increase in costs due to the provision of the flexible member 135C can be suppressed.

[0151] In addition, the shock absorber 1C has a stopper 142C having plate-shaped stopper members 261C, 262C, and 263C each formed from a plurality of annular plate-shaped members. The plurality of plate-shaped stopper members 261C and 262C are formed such that the outer diameter of the plate-shaped stopper member 262C provided on the opposite side of the valve member 133 is smaller than the outer diameter of the plate-shaped stopper member 261C provided on the valve member 133 side. The plurality of plate-shaped stopper members 262C and 263C are formed such that the outer diameter of the plate-shaped stopper member 263C provided on the opposite side of the valve member 133 is smaller than the outer diameter of the plate-shaped stopper member 262C provided on the valve member 133 side. This allows the spring constant, i.e., the deflection characteristic, of the stopper 142C to be changed.

[0152] [Fifth embodiment] Next, the fifth embodiment will be described with a focus on the differences from the third embodiment, mainly with reference to Fig. 7. The same parts as the third embodiment will be designated by the same names and symbols. As shown in FIG. 7, a shock absorber 1D of the fifth embodiment has a frequency sensitive mechanism 130D which is partially different from the frequency sensitive mechanism 130B instead of the frequency sensitive mechanism 130B.

[0153] The frequency sensitive mechanism 130D has a valve case 145D which is partially different from the valve case 145B instead of the valve case 145B. The number of discs 132 in the valve case 145D is different from the number of discs 132 in the valve case 145B. The total thickness of all the discs 132 in the valve case 145D is greater than the total thickness of all the discs 132 in the valve case 145B. The valve case 145D does not have the flexible member 135B and the discs 136.

[0154] The frequency sensitive mechanism 130D has a single flexible member 135D (plate-shaped member) separate from the valve case 145D. The flexible member 135D is provided between the valve disk 171 and the stopper disk 137 in the axial direction of the case member 131. The flexible member 135D is made of metal. The flexible member 135D is a disk-shaped member with holes. The flexible member 135D is inclined so that the more it is positioned on the outer periphery side in the radial direction, the more it is positioned on one side in the axial direction. The flexible member 135D is tapered circular. In other words, the flexible member 135D is formed so that the radially outer side is inclined to the axially one side with respect to the radially inner side. The flexible member 135D has a constant outer diameter over the entire circumference, and a constant radial width over the entire circumference. The flexible member 135D is elastically deformable, that is, flexible.

[0155] The mounting shaft portion 28 of the rod 21 and the multiple disks 132 are inserted into the inner periphery of the flexible member 135D. In this case, the flexible member 135D is oriented in the axial direction such that the outer periphery is closer to the valve disk 171 than the inner periphery. The flexible member 135D has a minimum inner diameter that allows the multiple disks 132 to be arranged on the radially inner side. That is, the minimum inner diameter of the flexible member 135D is slightly larger than the outer diameter of the multiple disks 132. Even when the flexible member 135D is deformed into a flat plate shape, the inner diameter of the flexible member 135D is slightly larger than the outer diameter of the disks 132. The flexible member 135D is restricted from moving in the radial direction by more than a predetermined value by the multiple disks 132 arranged on the radially inner side.

[0156] The flexible member 135D is disposed on the opposite side of the valve member 133 from the bottom portion 150 of the valve disc 171 in the axial direction. The flexible member 135D is elastically deformed in the axial direction between the valve disc 171 with the second support portion 179 in contact with the seat portion 154 and the stopper disc 137. As a result, the outer peripheral edge portion of the flexible member 135D is pressed against the first support portion 178 on the inner peripheral side of the valve disc 171 over the entire circumference. As a result, the gap between the flexible member 135D and the valve disc 171, i.e., the valve member 133, is closed. The flexible member 135D is elastically deformed in the axial direction between the valve disc 171 and the stopper disc 137. As a result, the inner peripheral edge portion of the flexible member 135D is pressed against the stopper disc 137 over the entire circumference. As a result, the gap between the flexible member 135D and the stopper disc 137, i.e., the stopper 142B, is closed. In valve case 145D, the position of the end face of support member 143 on the bottom 150 side in the axial direction of case member 131 is equivalent to the position of the end face of support member 143 on the bottom 150 side in the axial direction of case member 131 of valve case 145B.

[0157] The valve member 133 has a first support portion 178 on the inner circumferential side of the valve disc 171 disposed between the protruding portion 151 and the flexible member 135D in the axial direction. The first support portion 178 has one side opposite the bottom portion 150 in the axial direction in contact with the flexible member 135D and is supported by the flexible member 135D. The first support portion 178 of the valve disc 171 of the valve member 133 is movable between the protruding portion 151 and the flexible member 135D in the axial direction of the case member 131, and is movable until it deforms the flexible member 135D into a flat plate shape. Valve member 133 of frequency sensitive mechanism 130D has second support portion 179 supported by seat portion 154 and biasing portion 174 supported by support member 143, similar to valve member 133 of frequency sensitive mechanism 130B.

[0158] The valve member 133 is capable of bending such that the second support portion 179 moves away from the seat portion 154 while maintaining the state in which the first support portion 178 abuts against the bending member 135D. When bending in this manner, the valve member 133 bends such that the second support portion 179 moves toward the opposite side to the bottom portion 150 than the first support portion 178 in the axial direction of the case member 131.

[0159] The flexible member 135D is flexible together with the valve member 133. The flexible member 135D is flexible in the opposite direction to the bottom portion 150 due to movement and deformation of the valve member 133 in the axial direction opposite to the seat portion 154. When the flexible member 135D thus flexible becomes flat, the stopper 142B suppresses the amount of further bending of the flexible member 135D. Here, even if the bending of the flexible member 135D is suppressed by the stopper 142B, the valve member 133 is flexible so as to move the second support portion 179 further away from the bottom portion 150 than the first support portion 178 in the axial direction of the case member 131.

[0160] In the shock absorber 1D of the fifth embodiment, during the extension stroke, the oil L from the upper chamber 19 (see FIG. 2) is introduced into the first chamber 181 through the first passage 43 (see FIG. 2), the passage in the notch 81 (see FIG. 2) of the disc 50, the passage in the groove portion 30 of the rod 21 shown in FIG. 7, and the passage in the passage groove 158 of the case member 131. Then, the valve disc 171 of the valve member 133 bends the flexible member 135D that abuts on the first support portion 178 in a direction away from the bottom portion 150 in the axial direction of the case member 131. In other words, the valve disc 171 compresses and deforms the flexible member 135D in the axial direction of the case member 131 between the stopper 142B. At the same time, the valve disc 171 compresses and deforms the biasing portion 174 that abuts on the support member 143 in the axial direction of the case member 131 between the support member 143. At the same time, the valve disc 171 bends in a tapered manner, with the contact point with the flexible member 135D as a fulcrum, so that the second support portion 179 is further away from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178. In this way, the valve disc 171 bends, with the contact point with the flexible member 135D as a fulcrum, so that the second support portion 179 is further away from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178.

[0161] As the introduction of oil liquid L into first chamber 181 progresses further, the deflection of deflection member 135 abutting against valve disc 171 is restricted by stopper 142B. Then, valve disc 171 deflects in a tapered shape with the contact point with deflection member 135D as a fulcrum so that second support portion 179 is further separated from bottom 150 in the axial direction of case member 131 than first support portion 178, while further compressively deforming biasing portion 174 between support member 143 and valve disc 171 in the axial direction of case member 131. By the movement and deformation of the valve disc 171 as described above, the valve member 133 increases the volume of the first chamber 181. Here, the first support portion 178 of the valve disc 171 and the flexible member 135D form a check valve 193D that operates similarly to the check valve 193 by closing when they come into contact with each other and opening when they move away from each other.

[0162] The shock absorber 1D of the fifth embodiment includes a flexible member 135D that abuts against the first support portion 178 of the valve member 133 and is flexible together with the valve member 133. Therefore, similar to the shock absorber 1, the shock absorber 1D can improve the durability of the valve member 133 while ensuring the volume of the oil liquid L that can be received in the first chamber 181. At the same time, the shock absorber 1D can facilitate the initial movement of the valve member 133 when the oil liquid L is received in the first chamber 181. Furthermore, in the shock absorber 1D, the stopper 142B suppresses the amount of bending of the bending member 135D, so that, similarly to the shock absorber 1, the durability of the bending member 135D can be improved.

[0163] In addition, in shock absorber 1D, valve member 133 can bend even when the bending of bending member 135D is suppressed by stopper 142B, so that, like shock absorber 1, the volume of oil liquid L that can be received in first chamber 181 can be further secured. Furthermore, in the shock absorber 1D, the flexible member 135D is formed of an annular plate-shaped member, so similarly to the shock absorber 1, an increase in costs due to the provision of the flexible member 135D can be suppressed. In addition, in the shock absorber 1D, the flexible member 135D is formed to be inclined so that the radially outer side is located on one axial side relative to the radially inner side, so that it is possible to prevent excessive stress from being locally applied to the flexible member 135D, thereby further improving the durability of the flexible member 135D.

[0164] [Sixth embodiment] Next, the sixth embodiment will be described with a focus on the differences from the fifth embodiment, mainly with reference to Fig. 8. Note that parts common to the fifth embodiment will be designated by the same names and reference numerals. As shown in FIG. 8, a shock absorber 1E of the sixth embodiment has a frequency sensitive mechanism 130E which is partially different from the frequency sensitive mechanism 130D instead of the frequency sensitive mechanism 130D.

[0165] The frequency sensitive mechanism 130E has a valve case 145E which is partially different from the valve case 145D in place of the valve case 145D. Valve case 145E has a different number of discs 132 than valve case 145D. The total thickness of all of the discs 132 in valve case 145E is smaller than the total thickness of all of the discs 132 in valve case 145D. The frequency sensitive mechanism 130E has a flexible member 135E (plate-shaped member) instead of the flexible member 135D. The flexible member 135E constitutes a valve case 145E.

[0166] The flexible member 135E is made of metal and has a base portion 271E and a flexible portion 272E. The base portion 271E is a circular flat plate having a constant thickness and a hole. The base portion 271E has a constant inner diameter over the entire circumference and a constant radial width over the entire circumference. The radial width of the base portion 271E is slightly larger than the radial width of the disk 132.

[0167] The flexible portion 272E extends from the entire circumference of the outer peripheral edge of the base portion 271E to the outside in the radial direction of the base portion 271E and to one side in the axial direction of the base portion 271E. The flexible portion 272E is circular and tapered. In other words, the flexible portion 272E is inclined so that the closer it is to the outer periphery in the radial direction, the closer it is to one side in the axial direction. The flexible portion 272E has a constant outer diameter over the entire circumference and a constant radial width over the entire circumference. The flexible portion 272E is elastically deformable, i.e., flexible.

[0168] The flexible member 135E has a base portion 271E and a flexible portion 272E that are seamlessly formed integrally. The flexible member 135E has a base portion 271E that is sandwiched between the disks 132 at the opposite end of the disks 132 from the protruding portion 151 and the stopper disk 137 of the stopper 142B and abuts against them. At this time, the flexible member 135E is oriented such that the flexible portion 272E extends toward the valve disk 171 side more than the base portion 271E in the axial direction. The total thickness of all the disks 132 between the protruding portion 151 of the case member 131 and the base portion 271E and the base portion 271E is equal to the total thickness of all the disks 132 of the valve case 145D. The flexible member 135E has the mounting shaft portion 28 of the rod 21 fitted inside the base portion 271E. This causes the flexible member 135E and the rod 21 to have the same central axis. In the valve case 145E, the position of the end face of the support member 143 on the bottom 150 side in the axial direction of the case member 131 is the same as the position of the end face of the support member 143 on the bottom 150 side in the axial direction of the case member 131 of the valve case 145D.

[0169] The flexible member 135E is disposed on the opposite side of the valve member 133 from the bottom portion 150 of the valve disc 171 in the axial direction. The flexible member 135E has its flexible portion 272E elastically deformed in the axial direction between the valve disc 171 with the second support portion 179 abutting against the seat portion 154, and the stopper disc 137. As a result, the outer peripheral edge portion of the flexible portion 272E of the flexible member 135E is pressed against the first support portion 178 on the inner peripheral side of the valve disc 171 over the entire circumference. As a result, the gap between the flexible member 135E and the valve disc 171, i.e., the valve member 133, is closed.

[0170] The valve member 133 has a first support portion 178 on the inner circumferential side of the valve disc 171 disposed between the protruding portion 151 and the flexible member 135E in the axial direction. The first support portion 178 has one side opposite the bottom portion 150 in the axial direction in contact with the flexible member 135E and is supported by the flexible member 135E. The first support portion 178 of the valve disc 171 of the valve member 133 is movable between the protruding portion 151 and the flexible member 135E in the axial direction of the case member 131, and is movable until it deforms the flexible portion 272E of the flexible member 135E into a flat plate shape. Valve member 133 of frequency sensitive mechanism 130E has second support portion 179 supported by seat portion 154 and biasing portion 174 supported by support member 143, similar to valve member 133 of frequency sensitive mechanism 130D.

[0171] The valve member 133 is capable of bending such that the second support portion 179 moves away from the seat portion 154 while maintaining the state in which the first support portion 178 abuts against the bending member 135E. When bending in this manner, the valve member 133 bends such that the second support portion 179 moves toward the opposite side to the bottom portion 150 than the first support portion 178 in the axial direction of the case member 131.

[0172] The flexible member 135E has a flexible portion 272E that can bend together with the valve member 133. The flexible member 135E is bent in the opposite direction to the bottom portion 150 due to movement and deformation of the valve member 133 in the axial direction away from the seat portion 154. When the bent flexible portion 272E becomes flat, the stopper 142B suppresses the amount of further bending of the flexible portion 272E. Here, even if the bending of the flexible portion 272E is suppressed by the stopper 142B, the valve member 133 is bendable so as to move the second support portion 179 further away from the bottom portion 150 than the first support portion 178 in the axial direction of the case member 131.

[0173] In the shock absorber 1E of the sixth embodiment, during the extension stroke, the oil L from the upper chamber 19 (see FIG. 2) is introduced into the first chamber 181 through the first passage 43 (see FIG. 2), the passage in the notch 81 (see FIG. 2) of the disc 50, the passage in the groove portion 30 of the rod 21 shown in FIG. 8, and the passage in the passage groove 158 of the case member 131. Then, the valve disc 171 of the valve member 133 bends the bending portion 272E that abuts on the first support portion 178 in a direction away from the bottom portion 150 in the axial direction of the case member 131. At the same time, the valve disc 171 compresses and deforms the biasing portion 174 that abuts on the support member 143 in the axial direction of the case member 131 between the support member 143. At the same time, the valve disc 171 bends in a tapered manner, with the contact point with the flexible portion 272E as a fulcrum, so that the second support portion 179 is further away from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178. In this way, the valve disc 171 bends, with the contact point with the flexible portion 272E as a fulcrum, so that the second support portion 179 is further away from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178.

[0174] As the introduction of oil liquid L into first chamber 181 progresses further, the deflection of deflection portion 272E abutting against valve disc 171 is restricted by stopper 142B. Then, valve disc 171 deflects in a tapered shape with the contact point with deflection portion 272E as a fulcrum so that second support portion 179 is further separated from bottom portion 150 in the axial direction of case member 131 than first support portion 178, while further compressively deforming biasing portion 174 between support member 143 and valve disc 171 in the axial direction of case member 131. By the movement and deformation of the valve disc 171 as described above, the valve member 133 increases the volume of the first chamber 181. Here, the first support portion 178 and the flexible portion 272E of the valve disc 171 form a check valve 193E that operates similarly to the check valve 193 by closing when they come into contact with each other and opening when they move away from each other.

[0175] The shock absorber 1E of the sixth embodiment includes a flexible member 135E that abuts against the first support portion 178 of the valve member 133 and is flexible together with the valve member 133. Therefore, similar to the shock absorber 1, the shock absorber 1E can improve the durability of the valve member 133 while ensuring the volume of the oil liquid L that can be received in the first chamber 181. At the same time, the shock absorber 1E can facilitate the initial movement of the valve member 133 when the oil liquid L is received in the first chamber 181. Furthermore, in the shock absorber 1E, the stopper 142B suppresses the amount of bending of the bending member 135E, so that, similarly to the shock absorber 1, the durability of the bending member 135E can be improved.

[0176] In addition, in the shock absorber 1E, the valve member 133 is capable of bending even when the bending of the bending member 135E is suppressed by the stopper 142B, so that, like the shock absorber 1, the volume of oil liquid L that can be received in the first chamber 181 can be further secured. Furthermore, in the shock absorber 1E, the flexible member 135E is formed of an annular plate-shaped member, so similarly to the shock absorber 1, an increase in costs due to the provision of the flexible member 135E can be suppressed. In addition, since the buffer 1E has a base portion 271E where the flexible member 135E is fixed to the rod 21 and a flexible portion 272E that abuts against the valve member 133 formed integrally, the number of parts can be reduced and assembly is made easier.

[0177] [Seventh embodiment] Next, the seventh embodiment will be described focusing on the differences from the fifth embodiment mainly with reference to Fig. 9. Note that the same names and symbols are used for the parts common to the fifth embodiment. As shown in FIG. 9, a shock absorber 1F of the seventh embodiment has a frequency sensitive mechanism 130F which is partially different from the frequency sensitive mechanism 130D instead of the frequency sensitive mechanism 130D.

[0178] The frequency sensitive mechanism 130F has a flexible member 135F instead of the flexible member 135D. The flexible member 135F is also separate from the valve case 145D. The flexible member 135F is formed of an annular elastic member. Specifically, the flexible member 135F is made of rubber. The flexible member 135F is elastically deformable, that is, flexible.

[0179] The mounting shaft portion 28 of the rod 21 and the multiple disks 132 are inserted into the inner periphery of the flexible member 135F. The flexible member 135F has a minimum inner diameter that allows the multiple disks 132 to be arranged on the radially inner side. In other words, the minimum inner diameter of the flexible member 135F is slightly larger than the outer diameter of the disks 132. The flexible member 135F is restricted from moving in the radial direction by more than a predetermined amount by the multiple disks 132 arranged on the radially inner side.

[0180] The flexible member 135F abuts against the valve disc 171 with the second support portion 179 abutting against the seat portion 154, and against the stopper disc 137, and is elastically deformed in the axial direction between them. This closes the gap between the flexible member 135F and the valve disc 171, i.e., the valve member 133, and also closes the gap between the flexible member 135F and the stopper disc 137, i.e., the stopper 142B.

[0181] The valve member 133 has a first support portion 178 on the inner circumferential side of the valve disc 171 disposed between the protruding portion 151 and the flexible member 135F in the axial direction. The first support portion 178 has one side opposite the bottom portion 150 in the axial direction in contact with the flexible member 135F and is supported by the flexible member 135F. The valve member 133 has a first support portion 178 on the inner circumferential side of the valve disc 171 movable between the protruding portion 151 and the flexible member 135F, and movable so as to compressively deform the flexible member 135F in the axial direction of the case member 131. The valve member 133 of the frequency sensitive mechanism 130F has a second support portion 179 supported by the seat portion 154 and a biasing portion 174 supported by the support member 143, similar to the valve member 133 of the frequency sensitive mechanism 130D.

[0182] The valve member 133 is capable of bending such that the second support portion 179 moves away from the seat portion 154 while the first support portion 178 maintains a state in which it abuts against the bending member 135F. When bending in this manner, the valve member 133 bends such that the second support portion 179 moves toward the opposite side to the bottom portion 150 than the first support portion 178 in the axial direction of the case member 131.

[0183] The flexible member 135F is flexible together with the valve member 133. Here, the valve member 133 is flexible so as to move the second support portion 179 further toward the opposite side from the bottom portion 150 than the first support portion 178 in the axial direction of the case member 131, even when the deformation of the flexible member 135F reaches its limit.

[0184] In the shock absorber 1F of the seventh embodiment, during the extension stroke, the oil L from the upper chamber 19 (see FIG. 2) is introduced into the first chamber 181 through the first passage 43 (see FIG. 2), the passage in the notch 81 (see FIG. 2) of the disc 50, the passage in the groove portion 30 of the rod 21 shown in FIG. 9, and the passage in the passage groove 158 of the case member 131. Then, the valve disc 171 of the valve member 133 bends the flexible member 135F that abuts on the first support portion 178 in a direction away from the bottom portion 150 in the axial direction of the case member 131. In other words, the valve disc 171 compresses and deforms the flexible member 135F in the axial direction of the case member 131 between the stopper 142B. At the same time, the valve disc 171 compresses and deforms the biasing portion 174 that abuts on the support member 143 in the axial direction of the case member 131 between the support member 143. At the same time, the valve disc 171 bends in a tapered manner, with the contact point with the flexible member 135F as a fulcrum, so that the second support portion 179 is further away from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178. In this way, the valve disc 171 bends, with the contact point with the flexible member 135F as a fulcrum, so that the second support portion 179 is further away from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178.

[0185] As the introduction of oil liquid L into the first chamber 181 progresses further and the flexible member 135F deforms to its limit, the valve disc 171 bends in a tapered manner, with the contact point with the flexible member 135F as a fulcrum, so that the second support portion 179 is further away from the bottom 150 in the axial direction of the case member 131 than the first support portion 178, while further compressing and deforming the biasing portion 174 in the axial direction of the case member 131 between the support member 143. By the movement and deformation of the valve disc 171 as described above, the valve member 133 increases the volume of the first chamber 181. Here, the first support portion 178 of the valve disc 171 and the flexible member 135F form a check valve 193F that operates similarly to the check valve 193 by closing when they come into contact with each other and opening when they move away from each other.

[0186] The shock absorber 1F of the seventh embodiment includes a flexible member 135F that abuts against the first support portion 178 of the valve member 133 and is flexible together with the valve member 133. Therefore, like the shock absorber 1, the shock absorber 1F can improve the durability of the valve member 133 while ensuring the volume of oil liquid L that can be received in the first chamber 181. At the same time, the shock absorber 1F can facilitate the initial movement of the valve member 133 when the oil liquid L is received in the first chamber 181.

[0187] In addition, in the shock absorber 1F, the valve member 133 is flexible even when the flexible member 135F is deformed to its limit, so that, like the shock absorber 1, the volume of oil liquid L that can be received in the first chamber 181 can be further secured. Furthermore, in the shock absorber 1F, the bending member 135F is formed of an annular elastic member, so that the sealing performance of the check valve 193F can be improved.

[0188] [Eighth embodiment] Next, the eighth embodiment will be described with a focus on the differences from the fifth embodiment, mainly with reference to Fig. 10. Note that parts common to the fifth embodiment will be designated by the same names and symbols. As shown in FIG. 10, a shock absorber 1G of the eighth embodiment has a frequency sensitive mechanism 130G which is partially different from the frequency sensitive mechanism 130D instead of the frequency sensitive mechanism 130D.

[0189] Frequency sensitive mechanism 130G has a valve member 133G (first valve) that is partially different from valve member 133, instead of valve member 133. Frequency sensitive mechanism 130G has a flexible member 135G that is partially different from flexible member 135D, instead of flexible member 135D. Flexible member 135G constitutes valve member 133G.

[0190] The flexible member 135G is formed of an annular elastic member. Specifically, the flexible member 135G is made of rubber. The flexible member 135G is elastically deformable, that is, flexible. The flexible member 135G is bonded to the inner circumferential side of the valve disc 171. The flexible member 135G is bonded to the same side of the valve disc 171 as the biasing portion 174 in the axial direction. This causes the flexible member 135G to close the gap with the valve disc 171. The flexible member 135G is annular. The flexible member 135G is baked onto the valve disc 171 and is provided integrally with the valve disc 171. The flexible member 135G has a smaller outer diameter and a larger inner diameter as it moves away from the valve disc 171 in the axial direction. As a result, the cross section of the flexible member 135G taken along a plane including the central axis thereof has a tapered mountain shape that becomes thinner as it moves away from the valve disc 171 in the axial direction.

[0191] With the second support portion 179 in contact with the seat portion 154, the valve member 133G is elastically deformed in the axial direction with the flexible member 135G in contact with the stopper disk 137. This closes the gap between the flexible member 135G and the stopper disk 137, i.e., the stopper 142B.

[0192] A first support portion 178 on the inner periphery of the valve disc 171 of the valve member 133G has one side opposite to the bottom portion 150 in the axial direction supported by the stopper disc 137 via the flexible member 135G. The first support portion 178 of the valve disc 171 of the valve member 133G is movable together with the flexible member 135G between the protrusion 151 and the stopper disc 137 in the axial direction of the case member 131, and is also movable so as to deform the flexible member 135G. Valve member 133G of frequency sensitive mechanism 130G has second support portion 179 supported by seat portion 154 and biasing portion 174 supported by support member 143, similar to valve member 133 of frequency sensitive mechanism 130D.

[0193] The valve member 133G is flexible so that the second support portion 179 moves away from the seat portion 154 while maintaining the state in which the flexible member 135G abuts against the stopper disc 137. When the valve member 133 is flexible in this manner, the valve member 133 is flexible so that the second support portion 179 moves further away from the bottom portion 150 than the first support portion 178 in the axial direction of the case member 131. The flexible member 135G is flexible together with the valve disc 171. Here, even if the deformation of the flexible member 135G reaches its limit, the valve disc 171 is flexible so that the second support portion 179 moves further away from the bottom portion 150 than the first support portion 178 in the axial direction of the case member 131.

[0194] In the shock absorber 1G of the eighth embodiment, during the extension stroke, the oil L from the upper chamber 19 (see FIG. 2) is introduced into the first chamber 181 through the first passage 43 (see FIG. 2), the passage in the notch 81 (see FIG. 2) of the disc 50, the passage in the groove portion 30 of the rod 21 shown in FIG. 10, and the passage in the passage groove 158 of the case member 131. Then, the valve disc 171 of the valve member 133G bends the flexible member 135G in the axial direction of the case member 131 in a direction away from the bottom portion 150. In other words, the valve disc 171 compresses and deforms the flexible member 135G in the axial direction of the case member 131 between the stopper 142B. At the same time, the valve disc 171 compresses and deforms the biasing portion 174, which is in contact with the support member 143, in the axial direction of the case member 131 between the support member 143. At the same time, the valve disc 171 bends in a tapered manner, with the flexible member 135G as a fulcrum, so that the second support portion 179 is farther from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178. In this way, the valve disc 171 bends, with the flexible member 135G as a fulcrum, so that the second support portion 179 is farther from the bottom portion 150 in the axial direction of the case member 131 than the first support portion 178.

[0195] As the introduction of oil liquid L into first chamber 181 progresses further and flexible member 135G deforms to its limit, valve disc 171 bends in a tapered manner, with flexible member 135G as the fulcrum, so that second support portion 179 is further away from bottom 150 in the axial direction of case member 131 than first support portion 178, while further compressing and deforming biasing portion 174 in the axial direction of case member 131 between support member 143. By the movement and deformation of the valve disc 171 as described above, the volume of the first chamber 181 of the valve member 133G increases. Here, a flexible member 135G of the valve member 133G and a stopper disk 137 form a check valve 193G that operates similarly to the check valve 193 by closing when they come into contact with each other and opening when they move away from each other.

[0196] The shock absorber 1G of the eighth embodiment includes a flexible member 135G that is bonded in contact with the first support portion 178 of the valve member 133 and is flexible together with the valve member 133. Therefore, similar to the shock absorber 1, the shock absorber 1G can improve the durability of the valve member 133 while ensuring the volume of oil liquid L that can be received in the first chamber 181. At the same time, the shock absorber 1G can facilitate the initial movement of the valve member 133 when the oil liquid L is received in the first chamber 181.

[0197] In addition, in the shock absorber 1G, the valve member 133G is flexible even when the flexible member 135G is deformed to its limit, so that, like the shock absorber 1, the volume of oil liquid L that can be received in the first chamber 181 can be further secured. Furthermore, in the shock absorber 1G, the bending member 135G is formed of an annular elastic member, so that the sealing performance of the check valve 193G can be improved.

[0198] Although the hydraulic shock absorber has been described as an example in the first to eighth embodiments, the above structure can also be applied to a shock absorber that uses water or air as the working fluid. [Industrial Applicability]

[0199] According to the above aspects of the present invention, it is possible to provide a shock absorber capable of improving the durability of a flexible plate-shaped valve, and thus the industrial applicability is high. [Explanation of symbols]

[0200] 1, 1A to 1G... shock absorber, 2... cylinder, 18... piston, 19... upper chamber, 20... lower chamber, 21... rod, 133, 133G... valve member (first valve), 135, 135A to 135E... flexible member (plate-shaped member), 135F, 135G... flexible member (elastic member), 142, 142A to 142D... stopper, 174... biasing portion, 178... first support portion, 179... second support portion, 191... second passage (passage), 261C to 263C... plate-shaped stopper member, 251B, 252B... annular member.

Claims

1. A cylinder in which a working fluid is sealed; a piston slidably fitted within the cylinder to divide the interior of the cylinder into two chambers; a rod having a first end fastened to the piston and a second end protruding from the cylinder; a passageway communicating between one chamber and the other chamber in the cylinder; a first valve having a flexible plate shape, the first valve including: a first support portion provided in the passage and having one axial side surface on a radially inner side supported thereon; a second support portion disposed radially outward from the first support portion and having one axial side surface opposite to the first support portion in the axial direction supported thereon; and a biasing portion, at least a portion of which is provided radially outward from the second support portion and biases the first valve toward the second support portion; a flexible member that is disposed so as to be separable from the first support portion and is flexible together with the first valve while being in contact with the first support portion; a stopper that suppresses the amount of bending of the bending member; Equipped with the first valve is deflectable even when the deflection of the deflection member is suppressed by the stopper; buffer.

2. The stopper has a plate-shaped stopper member formed from a plurality of annular plate-shaped members, The outer diameter of the plate-shaped stopper members provided on the side opposite to the first valve is smaller than the outer diameter of the plate-shaped stopper members provided on the first valve side. The shock absorber according to claim 1 .

3. The flexible member is formed of an annular elastic member. The shock absorber according to claim 1 or 2.

4. The flexible member is formed of an annular plate-like member. The shock absorber according to claim 1 or 2.

5. The flexible member is formed so as to be inclined such that the radially outer side is located on one axial side with respect to the radially inner side. The shock absorber according to claim 3.

6. The plate-like member has a plurality of annular members, The outer diameter of the annular members provided on the side opposite to the first valve is smaller than the outer diameter of the annular members provided on the first valve side. The shock absorber according to claim 4.

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