Shock absorber

Abstract

The shock absorber is provided with a first valve assembly connected with one axial end of a pipe cylinder, a piston assembly dividing an inner chamber of the pipe cylinder into a first chamber and a second chamber, a piston rod connected with the piston assembly at the axial middle position and extending out of the pipe cylinder through the first chamber, and a cup-shaped piece arranged in the second chamber. And a second valve assembly disposed in the second chamber and connected with the piston rod and entering and exiting from the cup. The cup has: a sleeve disposed in the second chamber with a radial gap between the sleeve and the tube; and a base adapter which is press-fitted and fixed in the sleeve and is disposed between the sleeve and the first valve assembly.

Description

Technical Field

[0001] The present disclosure relates to vibration absorbers.

[0002] This application claims priority based on U.S. patent application No. 17 / 954,389 filed in the United States on September 28, 2022, and its contents are incorporated herein. Background Art

[0003] A shock absorber is provided which increases the damping force when the rod reaches a prescribed range on the limit side during a contraction stroke in which the rod is pressed into a cylinder.

[0004] Patent Literature

[0005] Patent Document 1: U.S. Patent No. 9605726 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, in the vibration absorber, it is desired to suppress an increase in cost.

[0008] Therefore, an object of the present disclosure is to provide a vibration damper capable of suppressing an increase in cost.

[0009] Technical solutions to solve problems

[0010] In order to achieve the above-mentioned purpose, one mode of the shock absorber disclosed in the present invention comprises: a tube, the inner side of which becomes an inner chamber; a first valve assembly connected to one axial end of the tube; a piston assembly, which divides the inner chamber into a first chamber and a second chamber; a piston rod connected to the piston assembly at a middle position in the axial direction, and the piston rod extends from the tube through the first chamber; a cup-shaped member, which is arranged in the second chamber; and a second valve assembly, which is arranged in the second chamber and connected to the piston rod, and enters and exits from the cup-shaped member. The cup-shaped member has: a sleeve, which is arranged in the second chamber with a radial gap between it and the tube; a base adapter, which is pressed into and fixed in the sleeve, and is arranged between the sleeve and the first valve assembly.

[0011] Another mode of the shock absorber disclosed in the present invention comprises: a first tube; a piston rod, which is arranged in the first tube; a main piston and a first valve, which are arranged on the piston rod; a secondary piston and a second valve, which are arranged on the piston rod; and a second tube, which can accommodate the secondary piston, the secondary piston being formed by combining a first piston component and a second piston component, the first piston component having a first communication path inside or on the inner peripheral surface side, a seat for carrying the second valve being formed on an end surface opposite to the main piston, the second piston component being formed with the first communication path and a second communication path communicating with the inside of the second tube, and a ring member receiving groove for receiving a ring member being provided on the outer peripheral side of at least one of the first piston component and the second piston component and on the side of the abutting surface where the first piston component and the second piston component abut.

[0012] Effects of the Invention

[0013] According to the above-described aspects of the present disclosure, it is possible to suppress an increase in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a diagram showing the shock absorber according to the first embodiment of the present disclosure, and is a cross-sectional view taken along a cross section including the central axis CL.

[0015] Figure 2 is a diagram showing the main parts of the shock absorber. Figure 1 A partial enlarged cross-sectional view of .

[0016] Figure 3 is a diagram showing the main parts of the shock absorber. Figure 2 A partial enlarged cross-sectional view of .

[0017] Figure 4 It is a diagram showing a shock absorber according to a second embodiment of the present disclosure, and is a partially enlarged cross-sectional view taken along a cross section including the central axis CL.

[0018] Figure 5 It is a diagram showing a shock absorber according to a third embodiment of the present disclosure, and is a cross-sectional view taken along a cross section including the central axis CL.

[0019] Figure 6 is a diagram showing the main parts of the shock absorber. Figure 5 A partial enlarged cross-sectional view of . DETAILED DESCRIPTION

[0020] [First embodiment]

[0021] based on Figure 1 to Figure 3The shock absorber of the first embodiment of the present disclosure is described. It should be noted that, for the sake of convenience, the upper side in the drawings is referred to as "upper" and the lower side in the drawings is referred to as "lower". In addition, the reference symbol CL shown in each figure represents the central axis of the shock absorber.

[0022] like Figure 1 As shown, the shock absorber 1 of the first embodiment is a multi-tube hydraulic shock absorber. The shock absorber 1 is used in a vehicle, specifically, in a suspension device of an automobile. The shock absorber 1 includes a cylinder 2. The cylinder 2 includes a tube 3 (first tube) and a housing 5. The tube 3 is cylindrical. The housing 5 is cylindrical with a bottom. The inner diameter of the housing 5 is larger than the outer diameter of the tube 3. The tube 3 is arranged radially inside the housing 5. The central axis of the tube 3 coincides with the central axis of the housing 5. The inner side of the tube 3 becomes an inner chamber 6. The space between the tube 3 and the housing 5 becomes an oil storage chamber 7.

[0023] The housing 5 includes a main body 11 and a bottom 12. The main body 11 and the bottom 12 are seamlessly integrally formed. The main body 11 is cylindrical. The bottom 12 closes the lower part of the main body 11.

[0024] The shock absorber 1 includes a piston assembly 17. The piston assembly 17 is arranged in the tube 3 of the cylinder 2. The piston assembly 17 includes a piston 18 (main piston). The piston assembly 17 slidably fits the piston 18 in the tube 3. The piston 18 divides the inner chamber 6 in the tube 3 into two chambers, a first chamber 19 on one side and a second chamber 20 on the other side. In the axial direction of the tube 3, the first chamber 19 is located on the opposite side of the bottom 12 compared to the piston 18. In the axial direction of the tube 3, the second chamber 20 is located closer to the bottom 12 than the piston 18. In the cylinder 2, oil L as a working fluid is sealed in the inner chamber 6 in the tube 3. In the cylinder 2, oil L and gas G as a working fluid are sealed in the oil storage chamber 7 between the tube 3 and the housing 5.

[0025] The shock absorber 1 includes a piston rod 21. One side of the piston rod 21 in the axial direction is disposed in the tube 3 of the cylinder 2. One side of the piston rod 21 is connected to the piston assembly 17. The other side of the piston rod 21 in the axial direction extends from the cylinder 2 to the outside of the cylinder 2. The piston rod 21 is connected to the piston assembly 17 and extends out from the tube 3 and the housing 5, that is, the cylinder 2 through the first chamber 19.

[0026] In the shock absorber 1, the portion of the piston rod 21 extending from the cylinder 2 is arranged at the upper part and connected to the vehicle body. In addition, the mounting bracket 22 fixed to the main body 11 of the housing 5 is arranged at the lower part and connected to the wheel side of the vehicle.

[0027] The piston 18 is fixed to the piston rod 21. Therefore, the piston 18 and the piston rod 21 move together. For the shock absorber 1, the stroke of the piston rod 21 moving in the direction of increasing the extension amount from the cylinder 2 is an extension stroke in which the total length is extended. For the shock absorber 1, the stroke of the piston rod 21 moving in the direction of reducing the extension amount from the cylinder 2 is a contraction stroke in which the total length is reduced. For the shock absorber 1, the piston 18 moves toward the first chamber 19 side during the extension stroke. For the shock absorber 1, the piston 18 moves toward the second chamber 20 side during the contraction stroke.

[0028] A rod guide 23 is fitted on the upper opening side of the tube 3 and the upper opening side of the housing 5. A sealing member 24 is fitted on the housing 5 at the upper side of the rod guide 23. The rod guide 23 and the sealing member 24 are both annular. The piston rod 21 is inserted through the radial inner side of each of the rod guide 23 and the sealing member 24. The piston rod 21 slides relative to the rod guide 23 and the sealing member 24 along their axial directions. The piston rod 21 extends from the inside of the cylinder 2 to the outer side of the cylinder 2 closer to the sealing member 24.

[0029] The rod guide 23 restricts the piston rod 21 from moving radially relative to the tube 3 and the housing 5 of the cylinder 2. The piston rod 21 is fitted with the rod guide 23, and the piston 18 is fitted in the tube 3. As a result, the central axis of the piston rod 21 coincides with the central axis of the tube 3. The rod guide 23 supports the piston rod 21 so as to be movable in the axial direction of the piston rod 21. The outer peripheral portion of the sealing member 24 is in close contact with the housing 5. The inner peripheral portion of the sealing member 24 is in close contact with the outer peripheral portion of the piston rod 21. The piston rod 21 moves relative to the sealing member 24 in the axial direction of the sealing member 24. The sealing member 24 prevents the oil L in the tube 3 and the high-pressure gas G and oil L in the oil storage chamber 7 from leaking to the outside.

[0030] The rod guide 23 has a large diameter portion 28 and a small diameter portion 29. The outer diameter of the large diameter portion 28 is larger than the outer diameter of the small diameter portion 29. The small diameter portion 29 of the rod guide 23 is provided below the large diameter portion 28. The small diameter portion 29 of the rod guide 23 at the lower part is fitted with the inner circumference of the upper end of the tube 3. At this time, the upper end of the tube 3 abuts against the large diameter portion 28 in the axial direction of the tube 3. The large diameter portion 28 of the rod guide 23 at the upper part is fitted with the inner circumference of the upper part of the housing 5.

[0031] The first valve assembly 31 is placed on the bottom 12 of the housing 5. The first valve assembly 31 has a seat member 32. The seat member 32 is placed in contact with the upper surface of the bottom 12 of the housing 5. The seat member 32 is positioned radially relative to the housing 5. The seat member 32 has a large diameter portion 33 and a small diameter portion 34. The outer diameter of the large diameter portion 33 is larger than the outer diameter of the small diameter portion 34. In the seat member 32, the large diameter portion 33 is arranged at a lower part than the small diameter portion 34. The small diameter portion 34 at the upper part of the seat member 32 is fitted with the inner circumference of the lower end of the tube 3. At this time, the lower end of the tube 3 is in contact with the large diameter portion 33 in the axial direction of the tube 3. As a result, the first valve assembly 31 is connected to one axial end of the tube 3.

[0032] A fastening portion 35 is provided at the upper end of the housing 5. The fastening portion 35 is formed by fastening the upper end of the housing 5 to the inner side of the housing 5 in the radial direction. The seal member 24 is fixed to the cylinder 2 by being clamped by the fastening portion 35 and the rod guide 23. When the fastening portion 35 is formed, the seal member 24 is pressed toward the rod guide 23 along the axial direction of the housing 5 in a state where the bottom 12 of the housing 5 is placed on a base. Then, the seal member 24, the rod guide 23, the tube 3, and the seat member 32 are in contact with each other in the axial direction without a gap. As a result, an axial force is generated in the seal member 24, the rod guide 23, the tube 3, and the seat member 32. In this state, the fastening portion 35 is formed. Therefore, after the fastening portion 35 is formed, an axial force is generated in the seal member 24, the rod guide 23, the tube 3, and the seat member 32.

[0033] The piston rod 21 includes a rod body 41 and an extender 42 .

[0034] The rod body 41 has a main shaft portion 51 and a mounting shaft portion 52. Both the main shaft portion 51 and the mounting shaft portion 52 are rod-shaped. The outer diameter of the mounting shaft portion 52 is smaller than the outer diameter of the main shaft portion 51. The mounting shaft portion 52 extends from one axial end of the main shaft portion 51. The central axis of the mounting shaft portion 52 coincides with the central axis of the main shaft portion 51. The entire mounting shaft portion 52 is disposed in the tube 3. The main shaft portion 51 of the rod body 41 of the piston rod 21 slides relative to the rod guide 23 and the sealing member 24 along their axial directions.

[0035] like Figure 2 As shown, in the mounting shaft portion 52, the end portion of the mounting shaft portion 52 on the side opposite to the main shaft portion 51 in the axial direction is a threaded shaft portion 54. The threaded shaft portion 54 has a male thread formed on the outer periphery. In the mounting shaft portion 52, the portion between the main shaft portion 51 and the threaded shaft portion 54 in the axial direction of the mounting shaft portion 52 is a mating shaft portion 55. The outer peripheral surface of the mating shaft portion 55 is a cylindrical surface.

[0036] The extender 42 has a main shaft portion 61 and a mounting shaft portion 62. Both the main shaft portion 61 and the mounting shaft portion 62 are rod-shaped. The outer diameter of the mounting shaft portion 62 is smaller than the outer diameter of the main shaft portion 61. The mounting shaft portion 62 extends from one axial end of the main shaft portion 61. The central axis of the mounting shaft portion 62 is consistent with the central axis of the main shaft portion 61.

[0037] The main shaft portion 61 has a threaded hole 64 formed at the end portion of the main shaft portion 61 on the opposite side of the mounting shaft portion 62 in the axial direction. The threaded hole 64 is formed at the radial center position of the main shaft portion 61. The threaded hole 64 extends along the axial direction of the main shaft portion 61. The threaded hole 64 is open at the top.

[0038] In the mounting shaft portion 62, the end portion of the mounting shaft portion 62 on the opposite side of the main shaft portion 61 in the axial direction is a threaded shaft portion 65. The threaded shaft portion 65 has a male thread formed on the outer periphery. In the mounting shaft portion 62, the portion between the main shaft portion 61 and the threaded shaft portion 65 in the axial direction of the mounting shaft portion 62 is a fitting shaft portion 66. The outer periphery of the fitting shaft portion 66 is a cylindrical surface.

[0039] The rod body 41 has its threaded shaft portion 54 screwed into the threaded hole 64 of the extender 42. Thus, the rod body 41 and the extender 42 are connected so that the central axes coincide with each other. Thus, the piston rod 21 is formed. The entire extender 42 is disposed in the tube 3.

[0040] The piston 18 is mounted on the mounting shaft portion 52 of the rod body 41 of the piston rod 21. The piston 18 is disposed between the main shaft portion 51 of the rod body 41 and the extender 42. The piston 18 is fitted with the fitting shaft portion 55 of the mounting shaft portion 52.

[0041] A through hole 70 is formed in the piston 18 at the center in the radial direction thereof. The through hole 70 penetrates the piston 18 in the axial direction of the piston 18. The fitting shaft portion 55 of the rod body 41 is fitted in the through hole 70 in the piston 18. A first passage 71 and a second passage 72 are formed in the piston 18 on the outside of the through hole 70 in the radial direction of the piston 18. The first passage 71 and the second passage 72 penetrate the piston 18 in the axial direction of the piston 18. A plurality of the first passages 71 and the second passages 72 are formed in the piston 18. The first passages 71 and the second passages 72 are alternately arranged along the circumferential direction of the piston 18. Both the first passage 71 and the second passage 72 can connect the first chamber 19 and the second chamber 20.

[0042] The piston assembly 17 includes a first damping valve 75 (first valve) and a second damping valve 76 (second valve).

[0043] The first damping valve 75 is a disk valve formed by stacking a plurality of annular disks. The first damping valve 75 is engaged with the engagement shaft portion 55 of the rod body 41 on the inner side in the radial direction. The first damping valve 75 is arranged between the piston 18 and the extender 42. The outer peripheral portion of the first damping valve 75 is separated from the piston 18 to open the first passage 71. As a result, the first damping valve 75 flows the oil L from the first chamber 19 to the second chamber 20 via the first passage 71. At this time, the first damping valve 75 suppresses the flow of the oil L and generates a damping force. The first damping valve 75 is provided in the first passage 71, and suppresses the flow of the oil L generated in the first passage 71 during the extension stroke to generate a damping force. The outer peripheral portion of the first damping valve 75 abuts against the piston 18 to close the first passage 71. A fixed throttle hole (not shown) is provided in the portion between the first damping valve 75 and the piston 18. Even when the outer peripheral portion of the first damping valve 75 abuts against the piston 18 , the fixed orifice allows the oil L to flow from the first chamber 19 to the second chamber 20 via the first passage 71 .

[0044] The second damping valve 76 is a disk valve formed by stacking a plurality of annular disks. The second damping valve 76 is fitted with the fitting shaft portion 55 on the inner side thereof in the radial direction. The second damping valve 76 is arranged between the main shaft portion 51 of the rod body 41 and the piston 18. The outer peripheral portion of the second damping valve 76 is separated from the piston 18 to open the second passage 72. As a result, the second damping valve 76 circulates the oil L from the second chamber 20 to the first chamber 19 via the second passage 72. At this time, the second damping valve 76 suppresses the flow of the oil L and generates a damping force. The second damping valve 76 is provided in the second passage 72, and suppresses the flow of the oil L generated in the second passage 72 during the contraction stroke to generate a damping force. The outer peripheral portion of the second damping valve 76 abuts against the piston 18 to close the second passage 72. A fixed throttle hole (not shown) is provided in the portion between the second damping valve 76 and the piston 18. Even when the outer peripheral portion of the second damping valve 76 abuts against the piston 18 , the fixed orifice allows the oil L to flow from the second chamber 20 to the first chamber 19 via the second passage 72 .

[0045] The piston assembly 17 including the piston 18, the first damping valve 75, and the second damping valve 76 is mounted on the mounting shaft portion 52 of the rod body 41 by the extender 42. Therefore, the piston assembly 17 is arranged between the main shaft portion 51 of the rod body 41 and the extender 42. The piston assembly 17 is connected to the axial middle position of the piston rod 21. The piston 18, the first damping valve 75, and the second damping valve 76 are arranged on the piston rod 21.

[0046] The first valve assembly 31 includes, in addition to the seat member 32, a disk valve 82, a disk valve 83, a bolt 84, and a nut 85. The disk valve 82 is provided on the lower side of the seat member 32. The disk valve 83 is provided on the upper side of the seat member 32. The bolt 84 is inserted into the disk valve 83, the seat member 32, and the disk valve 82 from above. In this state, the nut 85 is screwed into the lower part of the bolt 84. Thus, the bolt 84 and the nut 85 attach the disk valve 82 and the disk valve 83 to the seat member 32.

[0047] The seat member 32 is in an annular shape. The seat member 32 has a base portion 88 and a protrusion 89. The base portion 88 is in a disk shape. Figure 3 As shown, the base portion 88 is formed with a through hole 90 at the center thereof in the radial direction. The through hole 90 penetrates the base portion 88 in the axial direction of the seat member 32. In the seat member 32, the bolt 84 is inserted through the through hole 90. In the seat member 32, a passage hole 91 and a passage hole 92 are formed on the outer side of the through hole 90 in the radial direction of the seat member 32. The passage hole 91 and the passage hole 92 penetrate the base portion 88 in the axial direction of the seat member 32. The passage hole 92 is located on the outer side of the passage hole 91 in the radial direction of the seat member 32. A plurality of passage holes 91 and a plurality of passage holes 92 are formed in the seat member 32.

[0048] The protrusion 89 protrudes downward from the outer periphery of the base 88. The protrusion 89 is arranged on the outer side of the base 88 in the radial direction than the passage hole 92. The protrusion 89 of the seat member 32 abuts against the bottom 12 of the housing 5. A passage groove 93 is formed on the protrusion 89, and the passage groove 93 penetrates the protrusion 89 in the radial direction of the seat member 32. The seat member 32 is provided with a plurality of passage grooves 93 at equal intervals along the circumference of the seat member 32. As a result, the seat member 32 and the bottom 12 of the housing 5 are in contact with each other. Figure 1 The main body 11 of the housing 5 is shown to be partially connected to the tube 3. Therefore, the oil storage chamber 7 is also formed between the seat member 32 and the bottom 12 of the housing 5.

[0049] like Figure 2 As shown, the vibration absorber 1 has a cup-shaped member 101. The cup-shaped member 101 is disposed in the second chamber 20. The cup-shaped member 101 has a sleeve 102 (second tube) and a base adapter 103.

[0050] The sleeve 102 is cylindrical. The outer diameter of the sleeve 102 is smaller than the inner diameter of the tube 3. The sleeve 102 is arranged radially inward of the tube 3. The central axis of the sleeve 102 coincides with the central axis of the tube 3. The sleeve 102 is arranged in the second chamber 20 with a radial gap between the sleeve 102 and the tube 3.

[0051] The sleeve 102 has a main body 111 and an expanded diameter portion 112. The main body 111 is cylindrical and is provided from the middle portion to the lower end portion in the axial direction of the sleeve 102. The expanded diameter portion 112 is provided at the upper end portion of the sleeve 102. The closer the expanded diameter portion 112 is to the upper end, the larger the inner diameter is. The closer the expanded diameter portion 112 is to the upper end, the larger the outer diameter is. The expanded diameter portion 112 expands in the axial direction of the sleeve 102 in a direction away from the main body 111.

[0052] The sleeve 102 is provided with a groove 116 extending in the axial direction of the sleeve 102 at the inner circumference of one axial end side thereof. The groove 116 is provided at the inner circumference of the upper end side of the sleeve 102. The groove 116 is recessed from the inner circumferential surface of the sleeve 102 to the outer side in the radial direction of the sleeve 102. The groove 116 extends from the enlarged diameter portion 112 to the upper part of the main body portion 111. On the sleeve 102, a plurality of grooves 116 are provided at equal intervals along the circumferential direction of the sleeve 102. The lengths of the plurality of grooves 116 from the upper end of the sleeve 102 are respectively different. In other words, the lengths of the plurality of grooves 116 in the axial direction of the sleeve 102 are respectively different.

[0053] The base adapter 103 is annular and includes a main plate portion 121 , a press-fit portion 122 , and a leg portion 123 .

[0054] The main board portion 121 is in the shape of a circular plate. Figure 3 As shown, a recessed portion 131 recessed upward from the lower surface of the main plate portion 121 is formed in the radial center portion on one axial side thereof.

[0055] The press-in portion 122 is provided at one axial end of the base adapter 103. The press-in portion 122 protrudes upward from the upper surface of the main board portion 121. The press-in portion 122 is cylindrical. The outer diameter of the press-in portion 122 is smaller than the outer diameter of the main board portion 121. The press-in portion 122 of the base adapter 103 is pressed into the lower end portion of the sleeve 102. At this time, the upper surface of the main board portion 121 abuts against the lower end portion of the sleeve 102. Thus, the base adapter 103 is fixed to the sleeve 102. In this way, the base adapter 103 is pressed and fixed to the sleeve 102.

[0056] The leg portion 123 is provided at an end portion on the side opposite to the press-fit portion 122 in the axial direction of the base adapter 103. The leg portion 123 protrudes downward from the outer peripheral portion of the main board portion 121. The leg portion 123 is cylindrical. The leg portion 123 is arranged on the outer side of the main board portion 121 in the radial direction of the main board portion 121. The inner peripheral portion 135 of the leg portion 123 on the radial inner side thereof increases in diameter as it moves away from the main board portion 121 in the axial direction of the base adapter 103. In other words, the inner peripheral portion 135 of the leg portion 123 increases in diameter as it moves away from the main board portion 121 in the axial direction.

[0057] A communication groove 136 is formed on the outer circumference of the main plate portion 121 and the leg portion 123, and the communication groove 136 penetrates the main plate portion 121 and the leg portion 123 in the axial direction of the base adapter 103. The communication groove 136 opens on the outer side in the radial direction of the base adapter 103. The communication groove 136 is formed on the main plate portion 121 radially outward of the sleeve 102. The communication groove 136 penetrates the leg portion 123 in the radial direction of the base adapter 103. Therefore, the communication groove 136 opens on the upper surface of the main plate portion 121, the outer circumferential surface of the main plate portion 121, the outer circumferential surface of the leg portion 123, the lower surface of the leg portion 123, and the inner circumferential surface of the leg portion 123. On the base adapter 103, a plurality of communication grooves 136 are provided at equal intervals along the circumferential direction of the base adapter 103.

[0058] The cup-shaped member 101 composed of the base adapter 103 and the sleeve 102 fixed to the base adapter 103 presses the main plate portion 121 of the base adapter 103 into the tube 3. At this time, the lower end of the leg portion 123 of the base adapter 103 in the cup-shaped member 101 is placed in contact with the upper surface of the outer peripheral portion of the base portion 88 of the seat member 32. At this time, the base adapter 103 is prevented from contacting the bolt 84 of the first valve assembly 31 by the recess 131. In addition, at this time, the leg portion 123 of the base adapter 103 surrounds the disk valve 83 of the first valve assembly 31 on the radial outside. In other words, the leg portion 123 is arranged separately from the disk valve 83 on the radial outside of the disk valve 83. The base adapter 103 placed on the first valve assembly 31 is provided between the sleeve 102 and the first valve assembly 31.

[0059] As described above, a press-fit portion 122 is provided at one axial end of the base adapter 103, which is pressed into the sleeve 102. A leg portion 123 is provided at the other axial end of the base adapter 103, which is placed on the first valve assembly 31. The inner peripheral portion 135 of the leg portion 123 increases in diameter toward the first valve assembly 31 in the axial direction of the base adapter 103.

[0060] The third chamber 141 is formed between the first valve assembly 31 and the base adapter 103. The third chamber 141 is connected to the portion between the tube 3 and the sleeve 102 of the second chamber 20 via the connecting passage 142 in the connecting groove 136 of the base adapter 103. In other words, the connecting passage 142 that connects the second chamber 20 and the third chamber 141 is provided in the leg portion 123 of the base adapter 103.

[0061] In the first valve assembly 31 , the plurality of passage holes 91 allow the oil L to flow between the third chamber 141 and the oil reservoir 7 . The plurality of passage holes 92 allow the oil L to flow between the oil reservoir 7 and the third chamber 141 .

[0062] The disk valve 82 on the oil storage chamber 7 side allows the oil L to flow from the third chamber 141 to the oil storage chamber 7 via the passage hole 91. On the other hand, the disk valve 82 restricts the flow of the oil L from the oil storage chamber 7 to the third chamber 141 via the passage hole 91. The disk valve 82 opens during the contraction stroke of the shock absorber 1, and the oil L flows from the second chamber 20 and the third chamber 141 to the oil storage chamber 7, thereby generating a damping force.

[0063] The disk valve 83 on the third chamber 141 side allows the oil L to flow from the oil storage chamber 7 to the third chamber 141 through the passage hole 92. On the other hand, the disk valve 83 restricts the flow of the oil L from the third chamber 141 to the oil storage chamber 7 through the passage hole 92. The disk valve 83 is always connected to the third chamber 141 and the passage hole 91. The disk valve 83 opens during the extension stroke of the shock absorber 1, and the oil L flows from the oil storage chamber 7 to the third chamber 141 and the second chamber, and generates a damping force. It should be noted that the disk valve 83 may also be set as a suction valve that flows the oil L from the oil storage chamber 7 to the third chamber 141 and the second chamber without actually generating a damping force.

[0064] The cup-shaped member 101 is as follows Figure 2 As shown, the sleeve 102 is open at the top. The shock absorber 1 has a second valve assembly 151. The second valve assembly 151 is arranged in the second chamber 20 and connected to the piston rod 21. The second valve assembly 151 is installed on the mounting shaft portion 62 of the extender 42. The second valve assembly 151 enters from the top through the opening at the upper end of the sleeve 102 relative to the cup-shaped member 101 and exits from the top.

[0065] The second valve assembly 151 includes a valve base 152 (sub-piston), a fitting member 153 (ring), and a third damping valve 154 (second valve).

[0066] like Figure 3 As shown, the valve base 152 has a first base member 161 (first piston member) and a second base member 162 (second piston member). The valve base 152 is formed by combining the first base member 161 and the second base member 162. The first base member 161 forms the upper portion of the valve base 152. The second base member 162 forms the lower portion of the valve base 152.

[0067] The first base member 161 is annular. A cutout 171 is formed at the outer circumference of the lower portion of the first base member 161. The cutout 171 is formed over the entire circumference of the first base member 161. The cutout 171 is annular.

[0068] The first base member 161 is formed with a through hole 172 at the center thereof in the radial direction. The through hole 172 penetrates the first base member 161 in the axial direction of the first base member 161. The engaging shaft portion 66 of the extender 42 engages with the through hole 172 on the first base member 161. A passage groove 173 is provided on the first base member 161 at the outer side of the through hole 172 in the radial direction of the first base member 161. A passage groove 174 and a passage hole 175 are provided on the first base member 161 between the through hole 172 and the cutout portion 171 in the radial direction of the first base member 161.

[0069] The passage groove 173 is formed at the upper end of the first base member 161. The passage groove 173 is recessed downward from the upper end surface 161a (one end surface) of the first base member 161. The passage groove 173 is annular and surrounds the through hole 172 radially outward. The passage groove 173 is open at the top.

[0070] In the upper end portion of the first base member 161, the portion of the first base member 161 that is closer to the inner side than the passage groove 173 in the radial direction becomes an annular inner seat 176, and the portion that is closer to the outer side than the passage groove 173 becomes an annular valve seat 177 (seat). On the first base member 161, the inner seat 176 and the valve seat 177 are formed on the upper end surface 161a, which is one end surface opposite to the piston 18.

[0071] The passage groove 174 is formed at the lower end of the first base member 161. The passage groove 173 is recessed upward from the lower end surface 161b (contact surface) of the first base member 161. The passage groove 174 is annular and surrounds the through hole 172 radially outward. The passage groove 174 opens downward.

[0072] The passage hole 175 is formed in the middle portion of the first base member 161 in the axial direction. The upper end of the passage hole 175 opens at the bottom position of the passage groove 173, and the lower end opens at the bottom position of the passage groove 174. The first base member 161 is provided with a plurality of passage holes 175 spaced apart in the circumferential direction of the first base member 161.

[0073] In the first base member 161, the passage in the passage groove 173, the passage in the plurality of passage holes 175, and the passage in the passage groove 174 constitute a communication passage 178 (first communication passage) that penetrates the first base member 161 in the axial direction. The first base member 161 has the communication passage 178 not on the surface on the outer peripheral side but on the inside or the inner peripheral surface side. Specifically, the first base member 161 has the communication passage 178 inside. The first base member 161 may also have the communication passage 178 on the inner peripheral surface side, that is, between the first base member 161 and the mating shaft portion 66 of the extender 42.

[0074] The second base member 162 is annular. A cutout 181 is formed on the outer circumference of the upper portion of the second base member 162. The cutout 181 is formed over the entire circumference of the second base member 162. The cutout 181 is annular.

[0075] A groove 182 is formed on the outer circumference of the lower portion of the second base member 162. The groove 182 is recessed from the outer circumference of the second base member 162 toward the inner side in the radial direction of the second base member 162. The groove 182 opens toward the outer side in the radial direction of the second base member 162. The groove 182 opens at the cutout 181. The groove 182 opens downward. A plurality of grooves 182 are formed on the second base member 162 at intervals along the circumferential direction of the second base member 162.

[0076] The second base member 162 is formed with a through hole 183 at the center thereof in the radial direction. The through hole 183 penetrates the second base member 162 in the axial direction of the second base member 162. The engaging shaft portion 66 of the extender 42 engages with the through hole 183 in the second base member 162. A passage groove 184 is provided on the second base member 162 at the outer side of the through hole 183 in the radial direction of the second base member 162. A passage hole 185 is provided on the second base member 162 between the through hole 183 and the cutout portion 181 in the radial direction of the second base member 162.

[0077] The passage groove 184 is formed at the upper end of the second base member 162. The passage groove 184 is recessed downward from the upper end surface 162a (contact surface) of the second base member 162. The passage groove 184 is annular and surrounds the through hole 183 radially outward. The passage groove 184 is open at the top.

[0078] The passage hole 185 is formed from the middle of the axial direction to the lower end of the second base member 162. The upper end of the passage hole 185 opens at the bottom position of the passage groove 184. The second base member 162 is provided with a plurality of passage holes 185 spaced apart along the circumferential direction of the second base member 162.

[0079] In the second base member 162, the passage in the passage groove 184 and the passage in the plurality of passage holes 185 constitute a communication passage 186 (second communication passage) that penetrates the second base member 162 in the axial direction. The second base member 162 has the communication passage 186 not on the surface on the outer peripheral side but on the inside or the inner peripheral surface side. Specifically, the second base member 162 has the communication passage 186 inside. The second base member 162 may also have the communication passage 186 on the inner peripheral surface side, that is, between the second base member 162 and the mating shaft portion 66 of the extender 42.

[0080] When the valve base 152 is fitted with the fitting shaft portion 66 of the extender 42, the first base member 161 is in contact with the upper end surface 162a of the second base member 162 at the lower end surface 161b. Then, the passage groove 173, the passage hole 175 and the passage groove 174 of the first base member 161 are connected with the passage groove 184 and the passage hole 185 of the second base member 162. These passage grooves 173, 174, 184 and the passage holes 175, 185 constitute a third passage 191. The third passage 191 is provided in the valve base 152 and penetrates the valve base 152 in the axial direction. The third passage 191 is constituted by the communication passage 178 of the first base member 161 and the communication passage 186 of the second base member 162.

[0081] One end of the communication passage 186 of the second base member 162 communicates with the communication passage 178 of the first base member 161. When the valve base 152 is inserted into the sleeve 102, the other end of the communication passage 186 of the second base member 162 communicates with the sleeve 102.

[0082] In the valve base 152, the cutout portion 171 of the first base member 161 and the cutout portion 181 of the second base member 162 form a configuration groove 195 (annular member storage groove). The configuration groove 195 is provided at the outer peripheral side of both the first base member 161 and the second base member 162, and at the lower end surface 161b and the upper end surface 162a side where the first base member 161 and the second base member 162 abut. The configuration groove 195 is recessed from the outer peripheral surface of the valve base 152 to the inner side in the radial direction of the valve base 152. The configuration groove 195 is annular. The configuration groove 195 opens radially outward. A plurality of groove portions 182 open in the configuration groove 195. The communication path 178 of the first base member 161 is provided on the inner side of the configuration groove 195 in the radial direction of the first base member 161. The communication path 186 of the second base member 162 is provided on the inner side of the arrangement groove 195 in the radial direction of the second base member 162 .

[0083] It should be noted that the configuration groove 195 may also be provided at a portion of the outer peripheral side of the first base member 161 and at a portion of the first base member 161 on the side of the lower end face 161b that abuts against the upper end face 162a of the second base member 162. Alternatively, the configuration groove 195 may also be provided at a portion of the outer peripheral side of the second base member 162 and at a portion of the second base member 162 on the side of the upper end face 162a that abuts against the lower end face 161b of the first base member 161. That is, the configuration groove 195 is provided at the outer peripheral side of at least one of the first base member 161 and the second base member 162 and at a lower end face 161b and an upper end face 162a that abut against the first base member 161 and the second base member 162.

[0084] The fitting component 153 is annular. The outer diameter of the fitting component 153 is larger than the outer diameter of the valve base 152. The fitting component 153 is arranged between the cutout portion 171 and the cutout portion 181 when the first base component 161 and the second base component 162 are assembled to the extender 42. Thus, the fitting component 153 is arranged in the configuration groove 195 of the valve base 152. The fitting component 153 can move in the axial direction relative to the valve base 152 in the configuration groove 195. In the valve base 152, the configuration groove 195 accommodates the fitting component 153. The fitting component 153 is made of brass or glass fiber reinforced plastic.

[0085] A clamping member 197 is provided between the inner circumference of the fitting member 153 and the bottom of the configuration groove 195. The clamping member 197 holds the fitting member 153 coaxially with respect to the valve base 152. The clamping member 197 has an axial passage 196 that penetrates in the axial direction. The clamping member 197 is, for example, cylindrical and has a plurality of grooves that penetrate in the axial direction formed on the outer circumference. The clamping member 197 is pressed into the inner circumference of the fitting member 153. Thus, the clamping member 197 is fixed to the fitting member 153. In the clamping member 197, the plurality of grooves formed on the outer circumference constitute the axial passage 196.

[0086] The third damping valve 154 is a disk valve formed by stacking a plurality of annular disks. The third damping valve 154 is fitted into the fitting shaft portion 66 of the extender 42 on the inner side in the radial direction. The third damping valve 154 is arranged between the main shaft portion 61 of the extender 42 and the valve base 152. The third damping valve 154 is placed on the valve seat 177 of the valve base 152. In other words, the valve base 152 has a valve seat 177 on which the third damping valve 154 is placed, formed on the upper end surface 161a of the valve base 152 that faces the piston 18. The outer peripheral side portion of the third damping valve 154 is separated from the valve seat 177 of the valve base 152 to open the third passage 191. The outer peripheral side portion of the third damping valve 154 abuts against the valve seat 177 of the valve base 152 to close the third passage 191.

[0087] The nut 201 is screwed with the threaded shaft portion 65 of the extender 42. The second valve assembly 151 including the valve base 152 and the third damping valve 154 is mounted on the mounting shaft portion 62 of the extender 42 through the nut 201. Figure 2 As shown, the second valve assembly 151 is provided on the piston rod 21 on the side closer to the first valve assembly 31 than the piston assembly 17. The valve base 152 is fixed to the piston rod 21. Therefore, the valve base 152 and the piston rod 21 move integrally. The valve base 152 and the third damping valve 154 are arranged on the piston rod 21. The sleeve 102 can accommodate the valve base 152.

[0088] Here, when the piston rod 21 is in the first predetermined range where the second valve assembly 151 is arranged on the upper side of the sleeve 102 and is not fitted into the sleeve 102 , the entire interior of the cup 101 becomes the second chamber 20 .

[0089] During the contraction stroke, the piston rod 21 moves from this state to a second prescribed range closer to the base adapter 103 than the first prescribed range. Then, the second valve assembly 151 enters the sleeve 102 from the expanded diameter portion 112 side of the sleeve 102. In other words, the sleeve 102 has an expanded diameter portion 112 on the side where the second valve assembly 151 including the valve base 152 is inserted. When the second valve assembly 151 enters the sleeve 102 from the expanded diameter portion 112 side of the sleeve 102, the fitting component 153 is fitted into the sleeve 102. At the beginning of the fitting, the fitting component 153 moves upward relative to the configuration groove 195 of the valve base 152 due to the friction force with the contacting sleeve 102. As a result, the fitting component 153 makes the upper surface abut against the valve base 152. Then, the axial passage 196 is blocked. In the subsequent contraction stroke, the fitting member 153 is pushed by the valve base 152 in a state of closing the axial passage 196 , and slides toward the base adapter 103 side in the sleeve 102 .

[0090] When the fitting part 153 of the second valve assembly 151 is fitted with the sleeve 102, the second chamber 20 is divided into a fourth chamber 211 and a fifth chamber 212. The fourth chamber 211 is a portion between the second valve assembly 151 and the base adapter 103 in the cup-shaped member 101. The fifth chamber 212 is a portion of the second chamber 20 other than the fourth chamber 211. The fifth chamber 212 is composed of a portion between the tube 3 and the cup-shaped member 101, and a portion between the piston assembly 17 and the second valve assembly 151.

[0091] In the contraction stroke within the second predetermined range, the second valve assembly 151 moves toward the base adapter 103 side together with the piston rod 21 in the state of blocking the axial passage 196 as described above. In the upper part of the second predetermined range, the fitting member 153 is located at the position of the plurality of grooves 116 provided in the sleeve 102, and the oil L flows from the fourth chamber 211 to the fifth chamber 212 through the plurality of grooves 116. At this time, the closer the second valve assembly 151 is to the base adapter 103, the number of grooves 116 among the plurality of grooves 116 through which the oil L flows from the fourth chamber 211 to the fifth chamber 212 decreases, and finally becomes zero.

[0092] In addition, in the contraction stroke within the second predetermined range, the second valve assembly 151 moves toward the base adapter 103 side in the state of closing the axial passage 196 as described above. At this time, the third damping valve 154 opens according to the movement speed of the piston rod 21, the piston 18, and the valve base 152 relative to the tube 3, that is, the piston speed. Then, the oil L flows from the fourth chamber 211 to the fifth chamber 212 via the third passage 191. Thus, the third damping valve 154 suppresses an excessive increase in the pressure of the fourth chamber 211. The third damping valve 154 is provided in the third passage 191, and the oil L flows from the fourth chamber 211 to the fifth chamber 212 while suppressing the flow of the oil L generated in the contraction stroke to generate a damping force. Here, the third damping valve 154 has a higher rigidity than the second damping valve 76 and is difficult to open. Therefore, the third damping valve 154 opens after the second damping valve 76 and generates a higher damping force than the second damping valve 76.

[0093] Starting from the state where the fitting component 153 is fitted into the sleeve 102 of the cup-shaped member 101, the second valve assembly 151 moves together with the piston rod 21 to the side opposite to the base adapter 103. Then, the fitting component 153 moves downward relative to the configuration groove 195 of the valve base 152 by the friction force with the sleeve 102. As a result, the fitting component 153 separates the upper surface from the valve base 152. Thus, the axial passage 196 is opened. In the subsequent extension stroke, the fitting component 153 is pushed by the valve base 152 in the state where the axial passage 196 is opened, and slides in the sleeve 102 to the side opposite to the base adapter 103. When the second valve assembly 151 moves to the side opposite to the base adapter 103, the oil L flows from the fifth chamber 212 to the fourth chamber 211 through the passage in the groove portion 182 of the valve base 152 from the axial passage 196. This reduces the resistance to the movement of the piston rod 21 in the extension direction.

[0094] The second valve assembly 151 starts from a state where the fitting part 153 is located closer to the base adapter 103 than all the grooves 116 in the sleeve 102, and is separated from the base adapter 103 by a predetermined distance during the extension stroke. Then, the groove 116 provided in the sleeve 102 opens in the fourth chamber 211. Then, the oil L flows from the fifth chamber 212 to the fourth chamber 211 via the groove 116. At this time, the farther the second valve assembly 151 is from the base adapter 103, the more the number of grooves 116 among the plurality of grooves 116 through which the oil L flows from the fifth chamber 212 to the fourth chamber 211 increases. As a result, the resistance to the movement of the piston rod 21 in the extension direction is reduced in stages.

[0095] Next, the main operation of the shock absorber 1 will be described.

[0096] “The piston rod 21 is within the first predetermined range of extension stroke”

[0097] {First region where the piston speed is slower than the first prescribed value}

[0098] In the first region of the extension stroke, the oil L from the first chamber 19 flows from the first passage 71 to the second chamber 20 through a fixed orifice (not shown) between the first damping valve 75 and the piston 18 in the piston assembly 17. Therefore, in the first region of the extension stroke, a damping force having an orifice characteristic (damping force is substantially proportional to the sum of the squares of the piston speed) is generated.

[0099] {Second region where the piston speed is greater than or equal to the first predetermined value}

[0100] In the second region of the extension stroke, the oil L from the first chamber 19 opens the first damping valve 75 from the first passage 71 in the piston assembly 17 and flows to the second chamber 20. Therefore, in the second region of the extension stroke, a damping force based on the valve characteristic of the first damping valve 75 (damping force is substantially proportional to piston speed) is generated.

[0101] “The piston rod 21 is in the retraction stroke of the first prescribed range”

[0102] {Third region where the piston speed is slower than the second specified value}

[0103] In the third region of the contraction stroke, the oil L from the second chamber 20 flows from the second passage 72 to the first chamber 19 through the fixed orifice (not shown) between the second damping valve 76 and the piston 18 in the piston assembly 17. Therefore, in the third region of the contraction stroke, a damping force of the orifice characteristic is generated.

[0104] {Fourth region where the piston speed is greater than or equal to the second predetermined value}

[0105] In the fourth range of the contraction stroke, the oil L from the second chamber 20 flows from the second passage 72 in the piston assembly 17 to open the second damping valve 76 and into the first chamber 19. Therefore, in the fourth range of the contraction stroke, a damping force based on the valve characteristics of the second damping valve 76 is generated.

[0106] “The piston rod 21 is in the retracted stroke of the second predetermined range”

[0107] In this contraction stroke, the piston assembly 17 operates in the same manner as in the first predetermined range. Then, the second valve assembly 151 moves toward the base adapter 103 in the axial direction of the tube 3, so that the fitting member 153 fits into the sleeve 102. Thus, in this initial stage, the fitting member 153 blocks the axial passage 196.

[0108] In the state where the axial passage 196 is blocked in this way, the second valve assembly 151 moves toward the base adapter 103 side. Then, the oil L flows from the fourth chamber 211 to the fifth chamber 212 via the plurality of grooves 116 provided in the sleeve 102. At this time, the closer the second valve assembly 151 is to the base adapter 103, the number of grooves 116 among the plurality of grooves 116 through which the oil L flows from the fourth chamber 211 to the fifth chamber 212 decreases, and finally becomes 0. As a result, the damping force of the second valve assembly 151 increases in stages, and the resistance to the movement of the piston rod 21 in the contraction direction increases in stages. Here, the press-fitting portion 122 of the base adapter 103 and the press-fitting axial length of the sleeve 102 are set so that the sleeve 102 will not fall off from the press-fitting portion 122 even if the fourth chamber 211 reaches the highest pressure.

[0109] Here, when the second valve assembly 151 moves toward the base adapter 103, the third damping valve 154 opens according to the piston speed. Then, the oil L flows from the fourth chamber 211 to the fifth chamber 212 via the third passage 191. Thus, an excessive increase in the pressure of the fourth chamber 211 is suppressed.

[0110] “The piston rod 21 is within the extension stroke of the second predetermined range”

[0111] In this extension stroke, the piston assembly 17 operates in the same manner as in the first predetermined range. Then, the second valve assembly 151 moves to the side opposite to the base adapter 103. Then, at the initial stage, the fitting member 153 opens the axial passage 196.

[0112] In the state where the axial passage 196 is opened in this way, the second valve assembly 151 moves to the side opposite to the base adapter 103. Then, the oil L flows from the fifth chamber 212 to the fourth chamber 211 via the axial passage 196 and the passage in the groove portion 182 of the valve base 152. When the fitting member 153 of the second valve assembly 151 passes through the groove 116 provided in the sleeve 102 from the state where it is located closer to the base adapter 103 than all the grooves 116 provided in the sleeve 102, the oil L flows from the fifth chamber 212 to the fourth chamber 211 via the groove 116. At this time, the farther the second valve assembly 151 is from the base adapter 103, the more the number of grooves 116 among the plurality of grooves 116 through which the oil L flows from the fifth chamber 212 to the fourth chamber 211 increases. In other words, the farther the second valve assembly 151 is from the base adapter 103, the lower the damping force is, and the lower the resistance to the movement of the piston rod 21 in the extension direction is.

[0113] The above-mentioned U.S. Patent No. 9,605,726 discloses a shock absorber in which, when the rod reaches a specified range on the limit side during the contraction stroke when the rod is pressed into the cylinder, the damping force is increased. However, it is desirable to suppress cost increases in the shock absorber. For example, FIG. 13 of the U.S. Patent No. 9,605,726 discloses a structure in which a tube is connected to a cup-shaped member, and the cup-shaped member is connected to a valve assembly. When the shock absorber is assembled, an axial force is input from the housing to the tube. According to the structure disclosed in FIG. 13 of the U.S. Patent No. 9,605,726, it is necessary to utilize a cup-shaped member to receive the axial force of the tube. Therefore, it is necessary to increase the strength of the cup-shaped member. As a result, costs increase.

[0114] The shock absorber 1 of the first embodiment includes a tube 3, a first valve assembly 31, a piston assembly 17, a piston rod 21, a cup 101, and a second valve assembly 151. The inner side of the tube 3 becomes an inner chamber 6. The first valve assembly 31 is connected to one axial end of the tube 3. The piston assembly 17 divides the inner chamber 6 into a first chamber 19 and a second chamber 20. In the piston rod 21, the piston assembly 17 is connected to the axial middle position and extends from the tube 3 through the first chamber 19. The cup 101 is set in the second chamber 20. The second valve assembly 151 is arranged in the second chamber 20 and is connected to the piston rod 21, and enters and exits relative to the cup 101. The cup 101 has a sleeve 102 and a base adapter 103. The sleeve 102 is arranged in the second chamber 20 with a radial gap between the sleeve 102 and the tube 3. The base adapter 103 is pressed into and fixed in the sleeve 102 , and is disposed between the sleeve 102 and the first valve assembly 31 .

[0115] When the shock absorber 1 is assembled, an axial force is inputted to the tube 3 from the fastening portion 35 of the housing 5 and the bottom 12 via the sealing member 24, the rod guide 23 and the first valve assembly 31. In the shock absorber 1, the first valve assembly 31 is connected to one axial end of the tube 3. Therefore, the axial force of the tube 3 can be received by the first valve assembly 31. Therefore, it is not necessary to receive the axial force of the tube 3 by the base adapter 103. Therefore, the strength of the base adapter 103 can be reduced compared to the case of receiving the axial force of the tube 3. As a result, the degree of freedom of the material of the base adapter 103 becomes higher, so a low-cost material can be selected. Therefore, the shock absorber 1 can suppress the increase in cost. In addition, a lightweight material can be selected for the base adapter 103. Therefore, the shock absorber 1 can suppress the increase in weight.

[0116] The shock absorber 1 presses and fixes the base adapter 103 in the sleeve 102. Therefore, the base adapter 103 and the sleeve 102 can be integrated before being assembled to the shock absorber 1. Therefore, the base adapter 103 and the sleeve 102 can be handled as one part, so the handling becomes easy, and the assembly to the shock absorber 1 also becomes easy.

[0117] The shock absorber 1 is provided with a press-fit portion 122 for press-fitting the sleeve 102 at one axial end of the base adapter 103, and a leg portion 123 for mounting the first valve assembly 31 is provided at the other axial end of the base adapter 103. In addition, a communication passage 142 for communicating the third chamber 141 between the first valve assembly 31 and the base adapter 103 and the second chamber 20 is provided in the leg portion 123. Thus, since the communication passage 142 is provided in the leg portion 123, the radial clearance between the tube 3 and the sleeve 102 can be reduced compared with the case where the communication passage is provided on the inner side of the leg portion 123 in the radial direction of the main plate portion 121.

[0118] In the shock absorber 1, the inner peripheral portion 135 of the leg portion 123 has a larger diameter as it approaches the first valve assembly 31. Thus, the outer diameter of the disk valve 83 of the first valve assembly 31 can be increased compared to a case where the inner peripheral portion 135 has a constant diameter. Therefore, the variable range of the damping force of the disk valve 83 can be increased. In particular, when the disk valve 83 is set as a suction valve that does not actually generate a damping force, the damping force can be made close to zero by setting the disk valve 83 to a large diameter.

[0119] US Patent No. 9,651,110 discloses a structure in which, in addition to a first piston member, a second piston member as a hydraulic stopper mechanism for hydraulic locking on the extension side is provided on the piston rod.

[0120] Japanese Patent Application Laid-Open No. 2022-133840 discloses a structure in which a first piston member is provided on a rod, and a second piston member is provided on a bracket corresponding to an extension rod.

[0121] European Patent No. 2910811 discloses a structure that utilizes two components to clamp a ring.

[0122] International Publication No. 2017 / 089425 discloses a structure in which the outer periphery of a ring member is provided as a passage.

[0123] However, in the shock absorber, it is desired to have a compact structure that increases the damping force near the moving end position of the piston rod.

[0124] The shock absorber 1 includes: a tube 3; a piston rod 21 disposed in the tube 3; a piston 18, a first damping valve 75, and a second damping valve 76 disposed on the piston rod 21; a valve base 152 and a third damping valve 154 disposed on the piston rod 21; and a sleeve 102 capable of accommodating the valve base 152. The valve base 152 is formed by combining a first base member 161 and a second base member 162. The first base member 161 has a communication path 178 inside. The first base member 161 has a valve seat 177 on which the third damping valve 154 is placed on an upper end surface 161a facing the piston 18. The second base member 162 has a communication path 178 and a communication path 186 communicating with the inside of the sleeve 102. An arrangement groove 195 for accommodating the fitting member 153 is provided on the outer peripheral side of at least one of the first base member 161 and the second base member 162 , on the lower end surface 161 b and the upper end surface 162 a side where the first base member 161 and the second base member 162 abut against each other.

[0125] In the contraction stroke of the shock absorber 1, the valve base 152 and the fitting member 153 enter the sleeve 102. Then, due to the friction force with the sleeve 102, the fitting member 153 moves relative to the valve base 152, closes the axial passage 196 between the valve base 152 and the valve base 152, and generates a damping force. The shock absorber 1 is provided with a third damping valve 154 on the valve base 152. When the hydraulic pressure in the fourth chamber 211 is higher than a predetermined pressure in the contraction stroke, the third damping valve 154 opens and releases the hydraulic pressure in the fourth chamber 211 to the fifth chamber 212 via the communication paths 178 and 186. Thus, the shock absorber 1 can suppress an excessive increase in hydraulic pressure in the contraction stroke when the valve base 152 enters the sleeve 102 and generates a damping force. In addition, during the extension stroke of the shock absorber 1, the fitting member 153 moves equivalently to the valve base 152 due to the friction force with the sleeve 102, and the axial passage 196 between the fitting member 153 and the valve base 152 is opened, so that the oil L flows smoothly from the fifth chamber 212 to the fourth chamber 211. As a result, the shock absorber 1 smoothly moves the valve base 152 and the fitting member 153 in the sleeve 102 during the extension stroke.

[0126] As described above, the shock absorber 1 can increase the damping force near the movement end position on the contraction side of the piston rod 21 and configure the valve base 152 , the fitting member 153 , and the third damping valve 154 in a compact manner.

[0127] The fitting member 153 of the vibration damper 1 is made of brass or glass fiber reinforced plastic.

[0128] The sleeve 102 of the shock absorber 1 has the enlarged diameter portion 112 on the side inserted by the second base member 162. Thus, when the shock absorber 1 increases the damping force near the movement end position on the contraction side of the piston rod 21, the damping force can be increased smoothly.

[0129] [Second Embodiment]

[0130] Then, mainly based on Figure 4 The shock absorber of the second embodiment will be described with the focus on the parts that are different from the first embodiment. It should be noted that the same parts as those of the first embodiment are represented by the same names and the same reference numerals. In addition, the reference numeral CL shown in each figure represents the central axis of the shock absorber.

[0131] The shock absorber 1A of the second embodiment includes a cup-shaped member 101A that is partially different from the cup-shaped member 101, instead of the cup-shaped member 101. The cup-shaped member 101A includes a sleeve 102A (second tube) that is partially different from the sleeve 102, instead of the sleeve 102. The sleeve 102A includes a main body 111A that is partially different from the main body 111, instead of the main body 111.

[0132] In the sleeve 102A, similar to the sleeve 102, a plurality of grooves 116 extending in the axial direction of the sleeve 102A are provided at the inner circumference of one axial end side thereof. In the sleeve 102A, a groove 116A extending in the axial direction of the sleeve 102A is also provided at the inner circumference of the other axial end side thereof. The groove 116A is provided at the inner circumference of the lower end of the sleeve 102A. The groove 116A is recessed from the inner circumferential surface of the sleeve 102A toward the outer side in the radial direction of the sleeve 102A. In the sleeve 102A, a plurality of grooves 116A are provided at equal intervals along the circumference of the sleeve 102A. The lengths of the plurality of grooves 116A from the lower end of the sleeve 102A are equal. In other words, the lengths of the plurality of grooves 116A in the axial direction of the sleeve 102A are equal.

[0133] The press-in portion 122 of the base adapter 103 is pressed into the lower end of the sleeve 102A. At this time, the upper surface of the main plate portion 121 abuts against the lower end of the sleeve 102A. As a result, the lower ends of the plurality of grooves 116A are closed, and the base adapter 103 is fixed to the sleeve 102A. The plurality of grooves 116A extend above the press-in portion 122.

[0134] The piston rod 21 moves from the first predetermined range in which the second valve assembly 151 is not fitted in the sleeve 102A to the second predetermined range during the contraction stroke. Then, the second valve assembly 151 fits the fitting member 153 in the sleeve 102A. In the initial stage of the fitting, the fitting member 153 blocks the axial passage 196.

[0135] In the contraction stroke within the second predetermined range, the second valve assembly 151 moves toward the base adapter 103 side together with the piston rod 21 in the state of blocking the axial passage 196. In the upper part of the second predetermined range, the fitting member 153 is located at the position of the plurality of grooves 116 provided in the sleeve 102A, and the oil L flows from the fourth chamber 211 to the fifth chamber 212 through the plurality of grooves 116. At this time, as the second valve assembly 151 approaches the base adapter 103 side, the number of grooves 116 through which the oil L flows from the fourth chamber 211 to the fifth chamber 212 decreases, and finally becomes zero.

[0136] In addition, in the contraction stroke within the second predetermined range, the second valve assembly 151 moves toward the base adapter 103 side in the state of closing the axial passage 196 as described above. At this time, the third damping valve 154 opens according to the piston speed. Then, the oil L flows from the fourth chamber 211 to the fifth chamber 212 via the third passage 191. Thus, the third damping valve 154 suppresses an excessive increase in the pressure of the fourth chamber 211.

[0137] Here, in the contraction stroke, when the second valve assembly 151 approaches the lower limit position of the second predetermined range, the fitting member 153 is located at the position of the plurality of grooves 116A provided in the sleeve 102A. Then, the oil L flows from the fourth chamber 211 to the fifth chamber 212 through the plurality of grooves 116A provided in the sleeve 102A. Thus, the plurality of grooves 116A suppresses an excessive increase in the pressure of the fourth chamber 211.

[0138] From this state, the second valve assembly 151 moves together with the piston rod 21 to the side opposite to the base adapter 103. Then, the fitting member 153 opens the axial passage 196. In this state, when the second valve assembly 151 moves to the side opposite to the base adapter 103, the oil L flows from the fifth chamber 212 to the fourth chamber 211 through the passage in the groove 182 of the valve base 152 from the axial passage 196. At the same time, the oil L flows from the fifth chamber 212 to the fourth chamber 211 through the plurality of grooves 116A. Thus, the resistance to the movement of the piston rod 21 in the extension direction is reduced.

[0139] When the fitting part 153 of the second valve assembly 151 is located on the side opposite to the base adapter 103 than all the grooves 116A in the sleeve 102A, the oil L flows from the fifth chamber 212 to the fourth chamber 211 only through the flow path from the axial passage 196 through the passage in the groove portion 182 of the valve base 152.

[0140] The shock absorber 1A of the second embodiment is provided with a groove 116 extending along the axial direction of the sleeve 102A on the inner circumference of one axial end side of the sleeve 102A, and a groove 116A extending along the axial direction of the sleeve 102A is provided on the inner circumference of the other axial end side of the sleeve 102A. As a result, at the beginning of the contraction stroke of the second specified range, the rate of change of the damping force becomes gentle through the groove 116 on the upper end side. Since there is no groove in the middle of the axial direction of the sleeve 102A, the damping force becomes larger at the middle position of the contraction stroke of the second specified range. At the lower end side of the second specified range, the groove 116A is used to suppress the increase of the damping force. The groove 116A can play a role in reducing pressure.

[0141] In addition, in the embodiment, the hydraulic shock absorber is exemplified as the shock absorber 1, 1A, but the above-mentioned structure can also be adopted for the shock absorber which uses water or air as a working fluid.

[0142] [Third Embodiment]

[0143] Then, mainly based on Figure 5 and Figure 6 The shock absorber of the third embodiment will be described with the focus on the parts different from the first embodiment. It should be noted that the same parts as those of the first embodiment are denoted by the same names and the same reference numerals. In addition, the reference numeral CL shown in each figure represents the central axis of the shock absorber.

[0144] like Figure 5 As shown, the shock absorber 1B of the third embodiment does not include the cup 101 included in the shock absorber 1 of the first embodiment. The shock absorber 1B includes a rod guide 23B that is partially different from the rod guide 23 instead of the rod guide 23 .

[0145] The rod guide 23B has the same large diameter portion 28, the intermediate diameter portion 29B, and the small diameter portion 231 as the rod guide 23. The outer diameter of the intermediate diameter portion 29B is smaller than the outer diameter of the large diameter portion 28. The outer diameter of the small diameter portion 231 is smaller than the outer diameter of the intermediate diameter portion 29B. The intermediate diameter portion 29B of the rod guide 23B is provided at a lower portion than the large diameter portion 28. The small diameter portion 231 of the rod guide 23B is provided at a lower portion than the intermediate diameter portion 29B. The large diameter portion 28 of the upper portion of the rod guide 23B is fitted with the inner circumference of the upper portion of the housing 5. The intermediate diameter portion 29B of the rod guide 23B is fitted with the inner circumference of the upper end of the tube 3. At this time, the upper end of the tube 3 abuts against the large diameter portion 28 in the axial direction of the tube 3.

[0146] The shock absorber 1B includes a sleeve 102B (second tube). The sleeve 102B is cylindrical. The outer diameter of the sleeve 102B is smaller than the inner diameter of the tube 3. The sleeve 102B is arranged radially inward of the tube 3B. The inner peripheral portion of the upper end of the sleeve 102B is engaged with the small diameter portion 231 of the lower portion of the rod guide 23B. At this time, the upper end of the sleeve 102B abuts against the intermediate diameter portion 29B in the axial direction of the sleeve 102B. The central axis of the sleeve 102B coincides with the central axis of the tube 3. The sleeve 102B is arranged in the first chamber 19 in a state where there is a radial gap between the sleeve 102B and the tube 3.

[0147] like Figure 6 As shown, the sleeve 102B has a main body 111B and an expanded diameter portion 112B. The main body 111B is cylindrical and is arranged from the upper end to the lower part of the sleeve 102B. The expanded diameter portion 112B is arranged at the lower end of the sleeve 102B. The closer the expanded diameter portion 112B is to the lower end, the larger the inner diameter is. The closer the expanded diameter portion 112B is to the lower end, the larger the outer diameter is. The expanded diameter portion 112B is expanded in the axial direction of the sleeve 102B in the direction away from the main body 111B.

[0148] The sleeve 102B is provided with a groove 116B extending in the axial direction of the sleeve 102B on the inner circumference of one axial end side thereof. The groove 116B is provided on the inner circumference of the lower end side of the sleeve 102B. The groove 116B is recessed from the inner circumferential surface of the sleeve 102B to the outer side in the radial direction of the sleeve 102B. The groove 116B extends from the enlarged diameter portion 112B to the lower part of the main body 111B. On the sleeve 102B, a plurality of grooves 116B are provided at equal intervals along the circumference of the sleeve 102B. The lengths of the plurality of grooves 116B from the lower end of the sleeve 102B are respectively different. In other words, the axial lengths of the sleeve 102B are respectively different in the plurality of grooves 116B.

[0149] The shock absorber 1B includes a piston rod 21B that is partially different from the piston rod 21, instead of the piston rod 21. The piston rod 21B includes a rod body 41B and an extender 42B.

[0150] The rod body 41B has a main shaft portion 51B and a mounting shaft portion 52B. Both the main shaft portion 51B and the mounting shaft portion 52B are rod-shaped. The outer diameter of the mounting shaft portion 52B is smaller than the outer diameter of the main shaft portion 51B. The mounting shaft portion 52B extends from one axial end of the main shaft portion 51B. The central axis of the mounting shaft portion 52B is consistent with the central axis of the main shaft portion 51B. The entire mounting shaft portion 52B is disposed in the tube 3. The piston rod 21B is as shown in FIG. Figure 5 As shown, the main shaft portion 51B of the rod body 41B slides relative to the rod guide 23B and the seal member 24 in the axial direction thereof.

[0151] like Figure 6As shown, in the mounting shaft portion 52B, the end portion of the mounting shaft portion 52B on the side opposite to the main shaft portion 51B in the axial direction becomes the threaded shaft portion 54B. The threaded shaft portion 54B has a male thread formed on the outer periphery. In the mounting shaft portion 52B, the portion between the main shaft portion 51B and the threaded shaft portion 54B in the axial direction of the mounting shaft portion 52B becomes the fitting shaft portion 55B. The outer peripheral surface of the fitting shaft portion 55B is a cylindrical surface.

[0152] The extender 42B has a base shaft portion 61B and a mounting shaft portion 62B. The base shaft portion 61B and the mounting shaft portion 62B are both rod-shaped. The outer diameter of the mounting shaft portion 62B is smaller than the outer diameter of the base shaft portion 61B. The mounting shaft portion 62B extends from one axial end of the base shaft portion 61B. The central axis of the mounting shaft portion 62B is consistent with the central axis of the base shaft portion 61B.

[0153] The base shaft portion 61B has a threaded hole 64B formed from the end portion of the base shaft portion 61B on the side opposite to the mounting shaft portion 62B in the axial direction to the middle portion. The threaded hole 64B is formed at the radial center position of the base shaft portion 61B. The threaded hole 64B extends along the axial direction of the base shaft portion 61B. The threaded hole 64B opens at the top.

[0154] In the mounting shaft portion 62B, the end portion of the mounting shaft portion 62B on the side opposite to the base shaft portion 61B in the axial direction is a threaded shaft portion 65B. The threaded shaft portion 65B has a male thread formed on the outer periphery. In the mounting shaft portion 62B, the portion between the base shaft portion 61B and the threaded shaft portion 65B in the axial direction of the mounting shaft portion 62B is a fitting shaft portion 66B. The outer periphery of the fitting shaft portion 66B is a cylindrical surface.

[0155] The rod body 41B is a rod body whose threaded shaft 54B is screwed into the threaded hole 64B of the extender 42B. Thus, the rod body 41B and the extender 42B are connected in a manner that the central axis is consistent. Thus, the piston rod 21B is formed. The entire extender 42B is arranged in the tube 3. Among the rod body 41B, the part on the side connected to the extender 42B is arranged in the tube 3, and the side opposite to the extender 42B extends out from the cylinder 2 to the outside.

[0156] In the piston rod 21B, a piston assembly 17 is installed on the mounting shaft portion 62B of the extender 42B, and the piston assembly 17 is composed of a piston 18 (main piston), a first damping valve 75 (first valve), and a second damping valve 76. At this time, the piston assembly 17 is engaged with the engaging shaft portion 66B of the extender 42B. The piston assembly 17 is installed on the extender 42B through a nut 201 that is screwed with the threaded shaft portion 65B of the extender 42B. The piston 18, the first damping valve 75, and the second damping valve 76 are arranged on the piston rod 21B. The piston assembly 17 composed of the piston 18, the first damping valve 75, and the second damping valve 76 is set on the front end side of the piston rod 21B.

[0157] The shock absorber 1B has a second valve assembly 151B. The second valve assembly 151B is arranged in the first chamber 19 and connected to the piston rod 21B. The second valve assembly 151B is mounted on the mounting shaft portion 52B of the rod body 41B. The second valve assembly 151B enters the sleeve 102B from below through the opening at the lower end of the sleeve 102B and exits downward.

[0158] The second valve assembly 151B includes a valve base 152B (sub-piston), a first fitting member 153B (ring), a second fitting member 233 (ring), and a third damping valve 154B (second valve).

[0159] The valve base 152B has a first base member 161B (first piston member) and a second base member 162B (second piston member). The valve base 152B is formed by combining the first base member 161B and the second base member 162B. The first base member 161B forms the lower portion of the valve base 152B. The second base member 162B forms the upper portion of the valve base 152B.

[0160] The first base member 161B is annular. The first base member 161B is formed with a through hole 172B at the center thereof in the radial direction. The through hole 172B penetrates the first base member 161B in the axial direction of the first base member 161B. In the first base member 161B, the engaging shaft portion 55B of the rod body 41B engages with the through hole 172B. In the first base member 161B, a passage groove 173B is provided on the outer side of the through hole 172B in the radial direction of the first base member 161B. In the first base member 161B, a passage groove 174B and a passage hole 175B are provided on the outer side of the through hole 172B in the radial direction of the first base member 161B.

[0161] The passage groove 173B is formed at the lower end of the first base member 161B. The passage groove 173B is recessed upward from the lower end surface 161Ba (one end surface) of the first base member 161B. The passage groove 173B is annular and surrounds the through hole 172B radially outward. The passage groove 173B is open at the bottom.

[0162] In the lower end of the first base member 161B, the portion of the first base member 161B that is closer to the inner side than the passage groove 173B in the radial direction becomes an annular inner seat 176B, and the portion that is closer to the outer side than the passage groove 173B becomes an annular valve seat 177B (seat). In the first base member 161B, the inner seat 176B and the valve seat 177B are formed on the lower end surface 161Ba, which is one end surface opposite to the piston 18.

[0163] The passage groove 174B is formed at the upper end of the first base member 161B. The passage groove 173B is recessed downward from the upper end surface 161Bb (contact surface) of the first base member 161B. The passage groove 174B is annular and surrounds the through hole 172B radially outward. The passage groove 174B is open at the top.

[0164] The passage hole 175B is formed in the middle portion of the first base member 161B in the axial direction. The lower end of the passage hole 175B opens at the bottom position of the passage groove 173B, and the upper end opens at the bottom position of the passage groove 174B. On the first base member 161B, a plurality of passage holes 175B are formed at intervals along the circumferential direction of the first base member 161B.

[0165] In the first base member 161B, the passage in the passage groove 173B, the passage in the plurality of passage holes 175B, and the passage in the passage groove 174B constitute a communication passage 178B (first communication passage) that penetrates the first base member 161B in the axial direction. The first base member 161B has the communication passage 178B not on the surface on the outer peripheral side but inside or on the inner peripheral surface side. Specifically, the first base member 161B has the communication passage 178B inside. The first base member 161B may also have the communication passage 178B on the inner peripheral surface side, that is, between the fitting shaft portion 55B of the rod body 41B.

[0166] The second base member 162B is annular. A cutout 181B is formed in the outer periphery from the middle portion to the lower portion in the axial direction of the second base member 162B. The cutout 181B is formed over the entire circumference of the second base member 162B. The cutout 181B is annular.

[0167] In the second base member 162B, a groove portion 182B is formed at the lower portion of the upper flange-shaped portion. The groove portion 182B is recessed upward from the lower surface of the flange-shaped portion of the second base member 162B. The groove portion 182B opens outward in the radial direction of the second base member 162. The groove portion 182B opens at the cutout portion 181. In the second base member 162B, a plurality of groove portions 182B are formed at intervals along the circumferential direction of the second base member 162B.

[0168] The second base member 162B is formed with a through hole 183B at the center thereof in the radial direction. The through hole 183B penetrates the second base member 162B in the axial direction of the second base member 162B. In the second base member 162B, the engaging shaft portion 55B of the rod body 41B engages with the through hole 183B. Moreover, the second base member 162B abuts against the end surface of the main shaft portion 51B of the rod body 41B on the side of the mounting shaft portion 52B. In the second base member 162B, a passage hole 185B is provided between the through hole 183B and the cutout portion 181B in the radial direction of the second base member 162B. In the second base member 162B, a passage groove 235 is provided on the outer side of the through hole 183B in the radial direction of the second base member 162B.

[0169] The passage groove 235 is formed at the upper end of the second base member 162B. The passage groove 235 is recessed downward from the upper surface 162Ba of the second base member 162B. The passage groove 235 is annular and surrounds the through hole 183B on the radially outer side. The passage groove 235 is open at the top. The passage groove 235 is opened on the radially outer side of the main shaft portion 51B of the rod body 41B that abuts against the upper surface 162Ba of the second base member 162B.

[0170] The passage hole 185B is formed from the bottom surface of the passage groove 235 to the lower end surface 162Bb (contact surface) of the second base member 162B. In other words, the upper end of the passage hole 185B opens at the bottom position of the passage groove 235, and the lower end opens at the lower end surface 162Bb of the second base member 162B. In the second base member 162B, a plurality of passage holes 185B are formed at intervals along the circumferential direction of the second base member 162B.

[0171] In the second base member 162B, the passage in the passage groove 235 and the passage in the plurality of passage holes 185B constitute a communication passage 186B (second communication passage) that penetrates the second base member 162B in the axial direction. The second base member 162B has the communication passage 186B not on the surface on the outer peripheral side but inside or on the inner peripheral surface side. Specifically, the second base member 162B has the communication passage 186B inside. The second base member 162B may also have the communication passage 186B on the inner peripheral surface side, that is, between the second base member 162B and the mating shaft portion 55B of the rod body 41B.

[0172] The first base member 161B is in a state of being fitted with the fitting shaft portion 55B of the rod body 41B, and the upper end surface 161Bb abuts against the lower end surface 162Bb of the second base member 162B. As a result, the passage groove 173B, the passage hole 175B and the passage groove 174B of the first base member 161B are connected with the passage hole 185B and the passage groove 235 of the second base member 162B. These passage grooves 173B, 174B, 235 and the passage holes 175B, 185B constitute the third passage 191B. The third passage 191B is provided on the valve base 152B and penetrates the valve base 152B in the axial direction. The third passage 191B is constituted by the communication passage 178B of the first base member 161B and the communication passage 186B of the second base member 162B.

[0173] One end of the communication passage 186B of the second base member 162B communicates with the communication passage 178B of the first base member 161B. When the valve base 152B enters the sleeve 102B, the other end of the communication passage 186B of the second base member 162B communicates with the inside of the sleeve 102B.

[0174] In the valve base 152B, the cutout portion 181B of the second base member 162B forms a configuration groove 195B (annular member storage groove) through the first base member 161B. The configuration groove 195B is provided at a portion of the first base member 161B and the second base member 162B on the outer peripheral side of the second base member 162B, and at a portion of the second base member 162B on the side of the lower end face 162Bb that abuts against the upper end face 161Bb of the first base member 161B. The configuration groove 195B is recessed from the outer peripheral surface of the valve base 152B to the inner side of the valve base 152B in the radial direction. The configuration groove 195B is annular. The configuration groove 195B opens radially outward. The communication path 178B of the first base member 161B is provided on the inner side of the configuration groove 195B in the radial direction of the first base member 161B. The communication path 186B of the second base member 162B is provided on the inner side of the arrangement groove 195B in the radial direction of the second base member 162B.

[0175] It should be noted that the configuration groove 195B may also be provided at the outer peripheral side of both the first base member 161B and the second base member 162B, and at the upper end face 161Bb and lower end face 162Bb side where the first base member 161B and the second base member 162B abut. Alternatively, the configuration groove 195B may also be provided at the outer peripheral side of the first base member 161B, and at the upper end face 161Bb side where the first base member 161B abuts against the lower end face 162Bb of the second base member 162B. That is, the configuration groove 195B is provided at the outer peripheral side of at least one of the first base member 161B and the second base member 162B, and at the upper end face 161Bb and lower end face 162Bb side where the first base member 161B and the second base member 162B abut.

[0176] The first interlocking component 153B is annular. The outer diameter of the first interlocking component 153B is larger than the outer diameter of the valve base 152B. When the first base component 161B and the second base component 162B are assembled to the rod body 41B, the first interlocking component 153B is arranged between the cutouts 181B of the first base component 161B and the second base component 162B. Thus, the first interlocking component 153B is arranged in the configuration groove 195B of the valve base 152B. The first interlocking component 153B can move axially relative to the valve base 152B in the configuration groove 195B. The configuration groove 195B of the valve base 152B accommodates the first interlocking component 153B. The first interlocking component 153B is made of brass or glass fiber reinforced plastic. The cross section of the first interlocking component 153B is C-shaped. In other words, a slit not shown in the figure is provided in a part of the radial direction, that is, the shape is not a continuous annular ring. This is because the first fitting member 153B is expanded in diameter by the internal pressure and comes into sliding contact with the main body portion 111B of the sleeve 102B.

[0177] The second interlocking component 233 is annular. The outer diameter of the second interlocking component 233 is larger than the outer diameter of the valve base 152B. When the first base component 161B and the second base component 162B are assembled to the rod body 41B, the second interlocking component 233 is arranged between the cutouts 181B of the first base component 161B and the second base component 162B. As a result, the second interlocking component 233 is arranged in the configuration groove 195B of the valve base 152B. At this time, the second interlocking component 233 is arranged on the lower side of the first interlocking component 153B. The second interlocking component 233 can move axially relative to the valve base 152B in the configuration groove 195B. The configuration groove 195B of the valve base 152B accommodates the second interlocking component 233. The second interlocking component 233 is made of an elastic material such as rubber, steel, brass, etc. The outer diameter of the first interlocking component 153B is larger than the outer diameter of the second interlocking component 233. This is because the outer diameter of the first interlocking component 153B is in sliding contact with the main body 111B of the sleeve 102B. The second interlocking component 233 does not have a slit like the first interlocking component 153B, and is annular. The second interlocking component 233 plays a role in preventing the oil flowing from the high-pressure side to the low-pressure side through the slit of the first interlocking component 153B from flowing out. In addition, the axial length of the second interlocking component 233 is shorter than the axial length of the first interlocking component 153B.

[0178] A gap is provided between the inner circumference of the first fitting component 153B and the bottom of the arrangement groove 195B. A gap is provided between the inner circumference of the second fitting component 233 and the bottom of the arrangement groove 195B. These gaps form an axial passage 196B that penetrates the first fitting component 153B and the second fitting component 233 in the axial direction.

[0179] The third damping valve 154B is a disk valve formed by stacking a plurality of annular disks. The third damping valve 154B is fitted with the fitting shaft portion 55B of the rod body 41B on the inner side in the radial direction. The third damping valve 154B is attached to the rod body 41B via an extender 42B that is screwed with the threaded shaft portion 54B of the rod body 41B in the threaded hole 64B.

[0180] The third damping valve 154B is placed on the valve seat 177B of the valve base 152B. In other words, the valve seat 177B on which the third damping valve 154B is placed is formed on one end surface of the valve base 152B that faces the piston 18. The outer peripheral side portion of the third damping valve 154B is separated from the valve seat 177B of the valve base 152B to open the third passage 191B. The outer peripheral side portion of the third damping valve 154B abuts against the valve seat 177B of the valve base 152B to close the third passage 191B.

[0181] like Figure 5As shown, the second valve assembly 151B is provided on the opposite side of the piston rod 21B from the piston assembly 17 to the first valve assembly 31. The valve base 152B is fixed to the piston rod 21B. Therefore, the valve base 152B and the piston rod 21B move integrally. The valve base 152B and the third damping valve 154B are arranged on the piston rod 21B. The sleeve 102B can accommodate the valve base 152B.

[0182] Here, when the piston rod 21B is in the third predetermined range where the second valve assembly 151B is arranged below the sleeve 102B and is not fitted into the sleeve 102B, the entire interior of the sleeve 102B serves as the first chamber 19 .

[0183] From this state, during the extension stroke, the piston rod 21B moves to the fourth prescribed range on the rod guide 23B side rather than the third prescribed range. Then, the second valve assembly 151B enters the sleeve 102B from the expanded diameter portion 112B side of the sleeve 102B. In other words, the sleeve 102B has the expanded diameter portion 112B on the side where the second valve assembly 151B including the valve base 152B is inserted. When the second valve assembly 151B enters the sleeve 102B from the expanded diameter portion 112B side of the sleeve 102B, the first fitting component 153B and the second fitting component 233 are fitted into the sleeve 102B. At the initial stage of the fitting, the first fitting component 153B compresses and deforms the second fitting component 233 by the friction force with the sleeve 102B in contact, and at the same time moves downward relative to the configuration groove 195B of the valve base 152B. As a result, the first fitting component 153B pushes the lower surface of the second fitting component 233 against the valve base 152B. Thus, the axial passage 196B is blocked by the second fitting component 233. In the subsequent extension stroke, the first fitting component 153B is pushed by the valve base 152B via the second fitting component 233 while the axial passage 196B is blocked by the second fitting component 233, and slides on the rod guide 23B side in the sleeve 102B.

[0184] The first chamber 19 is divided into a third chamber 241 and a fourth chamber 242 when the first fitting part 153B and the second fitting part 233 of the second valve assembly 151B are fitted with the sleeve 102B. The third chamber 241 is a portion between the second valve assembly 151B and the rod guide 23B in the sleeve 102B. The fourth chamber 242 is a portion of the first chamber 19 other than the third chamber 241. The fourth chamber 242 is composed of a portion between the tube 3 and the sleeve 102B, and a portion between the piston assembly 17 and the second valve assembly 151B.

[0185] In the extension stroke within the fourth predetermined range, the second valve assembly 151B moves toward the rod guide 23B side together with the piston rod 21B in the state of blocking the axial passage 196B as described above. In the lower part of the fourth predetermined range, the first fitting member 153B is located at the position of the plurality of grooves 116B provided in the sleeve 102B, and the oil L flows from the third chamber 241 to the fourth chamber 242 through the plurality of grooves 116B. At this time, as the second valve assembly 151B approaches the rod guide 23B, the number of grooves 116B among the plurality of grooves 116B through which the oil L flows from the third chamber 241 to the fourth chamber 242 decreases, and finally becomes zero.

[0186] In addition, in the extension stroke within the fourth predetermined range, the second valve assembly 151B moves toward the rod guide 23B side in the state where the axial passage 196B is blocked as described above. At this time, the third damping valve 154B opens according to the movement speed of the piston rod 21B, the piston 18, and the valve base 152B relative to the tube 3, that is, the piston speed. Then, the oil L flows from the third chamber 241 to the fourth chamber 242 via the third passage 191B. Thus, the third damping valve 154B suppresses an excessive increase in the pressure of the third chamber 241. The third damping valve 154B is provided in the third passage 191B, and the oil L flows from the third chamber 241 to the fourth chamber 242 while suppressing the flow of the oil L generated in the extension stroke to generate a damping force. Here, the third damping valve 154B has a higher rigidity than the first damping valve 75, and is difficult to open. Therefore, the third damping valve 154B opens after the first damping valve 75, and generates a higher damping force than the first damping valve 75.

[0187] Starting from the state where the first fitting component 153B and the second fitting component 233 are fitted in the sleeve 102B, in the contraction stroke, the second valve assembly 151B moves together with the piston rod 21B to the side opposite to the rod guide 23B. Then, the first fitting component 153B and the second fitting component 233 move upward relative to the configuration groove 195B of the valve base 152B by the friction force with the sleeve 102B. As a result, the second fitting component 233 separates the lower surface from the valve base 152B. Thus, the axial passage 196B is opened. In the subsequent contraction stroke, the first fitting component 153B and the second fitting component 233 are pushed by the valve base 152B in the state where the axial passage 196B is opened, and slide in the sleeve 102B to the side opposite to the rod guide 23B. When the second valve assembly 151B moves to the side opposite to the rod guide 23B, the oil L flows from the fourth chamber 242 to the third chamber 241 via the axial passage 196B and the passages in the plurality of grooves 182B. This reduces the resistance to the movement of the piston rod 21B in the contraction direction.

[0188] The second valve assembly 151B starts from a state where the first fitting part 153B and the second fitting part 233 are located closer to the rod guide 23B than all the grooves 116B in the sleeve 102B, and moves away from the rod guide 23B by a predetermined distance during the contraction stroke. As a result, the groove 116B provided in the sleeve 102B opens in the third chamber 241. As a result, the oil L flows from the fourth chamber 242 to the third chamber 241 via the groove 116B. At this time, the further the second valve assembly 151B moves away from the rod guide 23B, the more the number of grooves 116B among the plurality of grooves 116B through which the oil L flows from the fourth chamber 242 to the third chamber 241 increases. As a result, the resistance to the movement of the piston rod 21B in the contraction direction is reduced in stages.

[0189] Next, the main operation of the shock absorber 1B will be described.

[0190] “The piston rod 21B is within the extension stroke of the third predetermined range”

[0191] {Fifth region where the piston speed is slower than the third specified value}

[0192] In the fifth region of the extension stroke, the oil L from the first chamber 19 flows from the first passage 71 to the second chamber 20 through the fixed orifice (not shown) between the first damping valve 75 and the piston 18 in the piston assembly 17. Therefore, in the fifth region of the extension stroke, a damping force of the orifice characteristic is generated.

[0193] {Sixth region where the piston speed is greater than or equal to the third predetermined value}

[0194] In the sixth range of the extension stroke, the oil L from the first chamber 19 flows from the first passage 71 in the piston assembly 17 to open the first damping valve 75 and into the second chamber 20. Therefore, in the sixth range of the extension stroke, a damping force based on the valve characteristics of the first damping valve 75 is generated.

[0195] “The piston rod 21B is in the retracted stroke within the third predetermined range”

[0196] {Seventh region where the piston speed is slower than the fourth specified value}

[0197] In the seventh region of the contraction stroke, the oil L from the second chamber 20 flows from the second passage 72 in the piston assembly 17 to the first chamber 19 through a fixed orifice (not shown) between the second damping valve 76 and the piston 18. Therefore, in the seventh region of the contraction stroke, a damping force of an orifice characteristic is generated.

[0198] {Eighth region where the piston speed is equal to or greater than the fourth predetermined value}

[0199] In the eighth range of the contraction stroke, the oil L from the second chamber 20 flows from the second passage 72 in the piston assembly 17 to open the second damping valve 76 and into the first chamber 19. Therefore, in the eighth range of the contraction stroke, a damping force based on the valve characteristics of the second damping valve 76 is generated.

[0200] “The piston rod 21B is within the extension stroke of the fourth predetermined range”

[0201] In this extension stroke, the piston assembly 17 operates in the same manner as in the third predetermined range. Then, the second valve assembly 151B moves toward the rod guide 23B in the axial direction of the tube 3, so that the first fitting member 153B and the second fitting member 233 are fitted into the sleeve 102B. Thus, in the initial stage, the first fitting member 153B and the second fitting member 233 block the axial passage 196B.

[0202] In the state where the axial passage 196B is blocked in this way, the second valve assembly 151B moves toward the rod guide 23B side. Then, the oil L flows from the third chamber 241 to the fourth chamber 242 via the plurality of grooves 116B provided in the sleeve 102B. At this time, the closer the second valve assembly 151B is to the rod guide 23B, the fewer the number of grooves 116B among the plurality of grooves 116B through which the oil L flows from the third chamber 241 to the fourth chamber 242, and finally becomes zero. As a result, the damping force of the second valve assembly 151B increases in stages, and the resistance to the movement of the piston rod 21B in the extension direction increases in stages. Here, the press-fit axial length of the small diameter portion 231 of the rod guide 23B and the sleeve 102B is set so that the sleeve 102B will not fall off from the small diameter portion 231 even if the third chamber 241 reaches the highest pressure.

[0203] Here, when the second valve assembly 151B moves toward the rod guide 23B, the third damping valve 154B opens according to the piston speed. Then, the oil L flows from the third chamber 241 to the fourth chamber 242 via the third passage 191B. Thus, an excessive increase in the pressure of the third chamber 241 is suppressed.

[0204] “The piston rod 21B is in the retracted stroke of the fourth prescribed range”

[0205] In this contraction stroke, the piston assembly 17 operates in the same manner as in the third predetermined range. Then, the second valve assembly 151B moves to the side opposite to the rod guide 23B. Thus, in the initial stage, the first fitting member 153B and the second fitting member 233 open the axial passage 196B and the passages in the plurality of grooves 182B.

[0206] In the state where the axial passage 196B and the passages in the plurality of grooves 182B are opened, the second valve assembly 151B moves to the side opposite to the rod guide 23B. Then, the oil L flows from the fourth chamber 242 to the third chamber 241 via the axial passage 196B and the passages in the plurality of grooves 182B. When the first fitting member 153B of the second valve assembly 151B passes through the groove 116B provided in the sleeve 102B from the state where it is located closer to the rod guide 23B than all the grooves 116B provided in the sleeve 102B, the oil L flows from the fourth chamber 242 to the third chamber 241 via the groove 116B. At this time, the farther the second valve assembly 151B is from the rod guide 23B, the more the number of grooves 116B among the plurality of grooves 116B through which the oil L flows from the fourth chamber 242 to the third chamber 241 increases. In other words, the farther the second valve assembly 151B is from the rod guide 23B, the lower the damping force is, and the lower the resistance to the movement of the piston rod 21B in the contraction direction is.

[0207] The shock absorber 1B includes: a tube 3; a piston rod 21B disposed in the tube 3; a piston 18, a first damping valve 75, and a second damping valve 76 disposed on the piston rod 21B; a valve base 152B and a third damping valve 154B disposed on the piston rod 21B; and a sleeve 102B capable of accommodating the valve base 152B. The valve base 152B is formed by combining a first base member 161B and a second base member 162B. The first base member 161B has a communication path 178B inside. The first base member 161B has a valve seat 177B on which the third damping valve 154B is placed on a lower end surface 161Ba facing the piston 18. The second base member 162B has a communication path 178B and a communication path 186B communicating with the inside of the sleeve 102B. Arrangement grooves 195B for accommodating the first fitting member 153B and the second fitting member 233 are provided on the outer peripheral side of at least one of the first base member 161B and the second base member 162B and on the upper end surface 161Bb and the lower end surface 162Bb sides where the first base member 161B and the second base member 162B abut against each other.

[0208] In the extension stroke of the shock absorber 1B, the valve base 152B, the first fitting member 153B and the second fitting member 233 enter the sleeve 102B. Then, due to the friction force with the sleeve 102B, the first fitting member 153B and the second fitting member 233 move relative to the valve base 152B, close the axial passage 196 between the valve base 152B and the valve base 152B, and generate a damping force. In the shock absorber 1B, the third damping valve 154B is provided on the valve base 152B. When the hydraulic pressure in the third chamber 241 is higher than the prescribed pressure in the extension stroke, the third damping valve 154B opens and releases the hydraulic pressure in the third chamber 241 to the fourth chamber 242 via the communication paths 178B and 186B. As a result, the shock absorber 1B can suppress an excessive increase in hydraulic pressure in the extension stroke when the valve base 152B enters the sleeve 102B and generates a damping force. Furthermore, in the contraction stroke of the shock absorber 1B, the first fitting member 153B and the second fitting member 233 accommodated in the arrangement groove 195B of the valve base 152B move relative to the valve base 152B by the friction force with the sleeve 102B, and the axial passage 196B between the valve base 152B and the valve base 152B is opened, so that the oil L flows smoothly from the fourth chamber 242 to the third chamber 241. Thus, the shock absorber 1B enables the valve base 152B, the first fitting member 153B, and the second fitting member 233 to move smoothly in the sleeve 102B in the contraction stroke.

[0209] As described above, the shock absorber 1B can increase the damping force near the extension side movement end position of the piston rod 21B, and the valve base 152B, the first fitting member 153B, the second fitting member 233, and the third damping valve 154B are all compactly configured.

[0210] The first fitting member 153B of the vibration damper 1B is made of brass or glass fiber reinforced plastic.

[0211] The sleeve 102B of the shock absorber 1B has an enlarged diameter portion 112B on the side into which the second base member 162B is inserted. Thus, the shock absorber 1B can smoothly increase the damping force when increasing the damping force near the extension side movement end position of the piston rod 21B.

[0212] In the vibration damper 1B according to the third embodiment, the same changes as those made to the sleeve 102A of the sleeve 102 may be applied to the sleeve 102B.

[0213] Industrial Applicability

[0214] According to the shock absorber of the above-described aspect of the present disclosure, it is possible to suppress an increase in cost.

[0215] Description of Reference Numerals

[0216] 1, 1A, 1B… shock absorber, 3… tube (first tube), 6… inner chamber, 17… piston assembly, 18… piston (main piston), 19… first chamber, 20… second chamber, 21, 21B… piston rod, 31… first valve assembly, 75… first damping valve (first valve), 76… second damping valve (first valve), 101, 101A… cup-shaped member, 102, 102A, 102B… sleeve (second tube), 103… base adapter, 112, 112B… enlarged diameter portion, 116, 116A… groove, 122… press-fit portion, 123… leg portion, 135… inner peripheral portion, 141… third chamber, 142… communication path, 151… second valve assembly, 152, 152B… valve base (second piston member), 153… fitting member (ring shaped part), 153B…first fitting part (annular part), 154, 154B…third damping valve (second valve), 161, 161B…first base part (first piston part), 161a…upper end surface (one end surface), 161b…lower end surface (contact surface), 161Ba…lower end surface (one end surface), 161Bb…upper end surface (contact surface), 162, 162B…second base part (second piston part), 162a…upper end surface (contact surface), 162Bb…lower end surface (contact surface), 177, 177B…valve seat (seat), 178, 178B…communication path (first communication path), 186, 186B…communication path (second communication path), 195, 195B…configuration groove, 233…second fitting part (annular part).

Claims

1. A shock absorber, characterized in that: have: The tube, the inside of which becomes the inner chamber; A first valve assembly connected to one axial end of the tube; a piston assembly, which divides the inner chamber into a first chamber and a second chamber; a piston rod connected to the piston assembly at a middle position in the axial direction and extending from the tube through the first chamber; a cup-shaped member disposed in the second chamber; as well as A second valve assembly is disposed in the second chamber and connected to the piston rod and is inserted into and removed from the cup-shaped member. The cup-shaped member has: a sleeve, which is arranged in the second chamber with a radial gap between the sleeve and the tube; A base adapter is pressed into and fixed to the sleeve and is disposed between the sleeve and the first valve assembly.

2. The shock absorber according to claim 1, characterized in that: A third chamber is provided between the first valve assembly and the base adapter, A pressing portion pressed into the sleeve is provided at one axial end of the base adapter. A leg portion mounted on the first valve assembly is provided at the other end of the axial direction of the base adapter. The leg portion is provided with a communication passage that connects the second chamber and the third chamber.

3. The shock absorber according to claim 2, characterized in that: The inner peripheral portion of the leg portion has a larger diameter as it moves toward the first valve assembly.

4. The shock absorber according to claim 1, characterized in that: Grooves extending in the axial direction of the sleeve are provided on an inner circumferential portion on one end side of the sleeve in the axial direction and on an inner circumferential portion on the other end side of the sleeve in the axial direction.

5. A shock absorber, characterized in that: have: a first tube; a piston rod disposed in the first tube; A main piston and a first valve, which are arranged on the piston rod; A secondary piston and a second valve, which are arranged on the piston rod; as well as a second tube, which can receive the secondary piston, The secondary piston is formed by combining a first piston component and a second piston component. The first piston member has a first communication passage inside or on the inner peripheral surface side, and a seat for mounting the second valve is formed on one end surface facing the main piston. The second piston member is formed with the first communication passage and a second communication passage communicating with the second tube. A ring accommodating groove for accommodating a ring is provided on the outer peripheral side of at least one of the first piston member and the second piston member and on the side of the contact surface where the first piston member and the second piston member contact each other.

6. The shock absorber according to claim 5, characterized in that The ring is made of brass or glass-fiber reinforced plastic.

7. The vibration absorber according to claim 5 or 6 The second tube has an expanded diameter portion on a side where the secondary piston is inserted.

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