Shock absorber and damping valve device

Abstract

To provide a shock absorber which can inhibit occurrence of abnormal noise, and to provide a damping valve device.SOLUTION: A shock absorber includes: a cylinder in which a working fluid is enclosed; a piston which partitions the interior of the cylinder; a first passage in which flow of the working fluid is generated by the piston moving in one direction; a first damping valve which provides a resistive force to flow of the working fluid from an upstream side chamber to a downstream side chamber of the first passage; a second passage in which flow of the working fluid is generated by the piston moving in the other direction; and a second damping disc valve which provides a resistive force to flow of the working fluid from an upstream side chamber to a downstream side chamber of the second passage. The second damping disc valve has: a third passage which constantly allows communication between the upstream side chamber and the downstream side chamber; and a fourth passage which communicates with the upstream side chamber. A variable chamber which communicates with the fourth passage and is partitioned by a partition member which moves in response to pressure change of the upstream side or the downstream side chamber is disposed overlapping with the second damping disc valve.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a shock absorber and damping valve arrangement. This application claims priority based on Patent Application No. 2022-086551, filed in Japan on May 27, 2022, the contents of which are incorporated herein by reference. [Background technology]

[0002] Some shock absorbers have a body valve (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2009-287752 [Patent Document 2] Japanese Patent No. 5443227 Summary of the Invention [Problem to be solved by the invention]

[0004] Meanwhile, there is a demand for suppressing the generation of abnormal noise in shock absorbers.

[0005] SUMMARY OF THE PRESENT EMBODIMENTS Accordingly, an object of the present invention is to provide a shock absorber and a damping valve device that are capable of suppressing the generation of abnormal noise. [Means for solving the problem]

[0006] One embodiment of the shock absorber according to the present invention comprises a cylinder in which a working fluid is sealed, a piston fitted in the cylinder and partitioning the interior of the cylinder, a first passage in which a flow of the working fluid is generated by movement of the piston in one direction, a first damping valve providing resistance to the flow of the working fluid from an upstream chamber to a downstream chamber of the first passage, a second passage in which a flow of the working fluid is generated by movement of the piston in the other direction, and a second damping disc valve providing resistance to the flow of the working fluid from the upstream chamber to the downstream chamber of the second passage, wherein the second damping disc valve has a third passage that constantly connects the upstream chamber and the downstream chamber, and a fourth passage that connects with the upstream chamber, and a variable chamber that is connected to the fourth passage and partitioned by a partition member that moves in response to a pressure change in the upstream or downstream chamber is arranged to be overlapped with the second damping disc valve.

[0007] One aspect of the damping valve device according to the present invention is a damping valve device that is connected to a cylinder in which a working fluid is sealed, and includes: a first passage through which a flow of the working fluid is generated by movement of a piston in the cylinder in one direction; a first damping valve that provides resistance to the flow of the working fluid from an upstream chamber of the first passage to a downstream chamber; a second passage through which a flow of the working fluid is generated by movement of the piston in the other direction; and a second damping disc valve that provides resistance to the flow of the working fluid from the upstream chamber to the downstream chamber of the second passage, wherein the second damping disc valve has a communication passage that communicates with the upstream chamber, and an accumulator mechanism that communicates with the communication passage and has a variable chamber partitioned by a partition member that moves in response to a pressure change in the upstream or downstream chamber is arranged on top of the second damping disc valve. Effect of the Invention

[0008] According to each of the above aspects of the present invention, it is possible to suppress the generation of abnormal noise. [Brief description of the drawings]

[0009] [Figure 1] 1 is a cross-sectional view showing a shock absorber according to a first embodiment of the present invention. [Diagram 2] 2 is a partial cross-sectional view showing a body valve and its periphery of the shock absorber of the first embodiment. FIG. [Diagram 3] 3 is a partial cross-sectional view showing a portion III in FIG. 2 of a body valve of the shock absorber according to the first embodiment. FIG. [Figure 4] FIG. 4 is a hydraulic circuit diagram of a body valve of the shock absorber according to the first embodiment. [Diagram 5] 5 is a characteristic diagram showing a simulation result of rod acceleration when transitioning from a compression stroke to an extension stroke in the shock absorber of the first embodiment and a shock absorber of a comparative example. FIG. [Figure 6] 5 is a characteristic diagram showing the characteristics of the damping force relative to the piston speed when the piston frequency is low and the piston speed is high in the shock absorber of the first embodiment and a shock absorber of a comparative example. FIG. [Figure 7] 5 is a characteristic diagram showing the characteristics of the damping force relative to the piston speed when the piston frequency is low and the piston speed is slow in the shock absorber of the first embodiment and a shock absorber of a comparative example. FIG. [Figure 8] 5 is a characteristic diagram showing the characteristics of the damping force relative to the piston speed when the piston speed is high at a high piston frequency in the shock absorber of the first embodiment and a shock absorber of a comparative example. FIG. [Figure 9] 5 is a characteristic diagram showing the characteristics of the damping force relative to the piston speed when the piston speed is slow at high frequency in the shock absorber of the first embodiment and a shock absorber of a comparative example. FIG. [Figure 10] 5 is a characteristic diagram showing the characteristics of damping force with respect to piston frequency when the piston speed is high in the shock absorber of the first embodiment and a shock absorber of a comparative example. FIG. [Figure 11] 6 is a partial cross-sectional view showing a main portion of a body valve of a shock absorber according to a second embodiment of the present invention. FIG. [Figure 12] FIG. 11 is a partial cross-sectional view showing a main portion of a body valve of a shock absorber according to a third embodiment of the present invention. [Figure 13] FIG. 11 is a partial cross-sectional view showing a partition member of the shock absorber according to the third embodiment. [Figure 14]FIG. 13 is a bottom view showing a partition member of the shock absorber according to the third embodiment. [Figure 15] FIG. 11 is a partial cross-sectional view showing a main portion of a body valve of a shock absorber according to a fourth embodiment of the present invention. [Figure 16] FIG. 11 is a partial cross-sectional view showing a partition member of the shock absorber according to the fourth embodiment. [Figure 17] FIG. 13 is a plan view showing a partition member of the shock absorber according to the fourth embodiment. [Figure 18] FIG. 13 is a hydraulic circuit diagram of a body valve of the shock absorber of the fourth embodiment. [Figure 19] FIG. 13 is a partial cross-sectional view showing a partition member of a shock absorber according to a fifth embodiment of the present invention. [Figure 20] FIG. 13 is a plan view showing a partition member of the shock absorber according to the fifth embodiment. [Figure 21] FIG. 13 is a partial cross-sectional view showing a main portion of a body valve of a shock absorber according to a sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [First embodiment] A first embodiment of the present invention will be described below with reference to FIGS.

[0011] FIG. 1 shows a shock absorber 11 of a first embodiment. This shock absorber 11 is used in a suspension device of a vehicle such as an automobile or a railroad car. Specifically, the shock absorber 11 is a hydraulic shock absorber used in a suspension device of an automobile. The shock absorber 11 includes a cylinder 17 having an inner tube 15 and an outer tube 16. The inner tube 15 is cylindrical. The outer tube 16 is cylindrical with a bottom. The inner diameter of the outer tube 16 is larger than the outer diameter of the inner tube 15. The outer tube 16 is provided radially outside the inner tube 15 and coaxially with the inner tube 15. A reservoir chamber 18 is formed between the outer tube 16 and the inner tube 15. The shock absorber 11 is a double-tube shock absorber.

[0012] The outer cylinder 16 has a body 20 and a bottom 21. The body 20 is cylindrical. The bottom 21 closes one axial end of the body 20. The end of the body 20 opposite the bottom 21 is an opening 22. The opening 22 of the outer cylinder 16 is also provided at one axial end of the cylinder 17. The bottom 21 of the outer cylinder 16 is also provided at the other axial end of the cylinder 17. In other words, one axial end of the cylinder 17 is open as the opening 22, and the other axial end is closed as the bottom 21.

[0013] The shock absorber 11 includes a valve base 25 and a rod guide 26 .

[0014] The valve base 25 is annular, and is provided at one axial end of the inner cylinder 15 and the outer cylinder 16. The valve base 25 constitutes a body valve 30 which is a damping valve device. One axial side of the outer periphery of the valve base 25 is a large diameter portion 31, and the other axial side of the outer periphery is a small diameter portion 32. The outer diameter of the large diameter portion 31 is larger than the outer diameter of the small diameter portion 32. Therefore, the outer periphery of the valve base 25 is stepped.

[0015] The valve base 25 is placed on the bottom 21 with the large diameter portion 31 side positioned closer to the bottom 21 than the small diameter portion 32 side in the axial direction. At this time, the valve base 25 is positioned radially with respect to the outer cylinder 16 at the large diameter portion 31. A passage groove 33 is formed in the valve base 25 at the position of the large diameter portion 31 in the axial direction, penetrating the valve base 25 in the radial direction. Here, the space between the valve base 25 and the bottom 21 communicates with the inner cylinder 15 and the outer cylinder 16 via the passage groove 33 formed in the valve base 25. The space between the valve base 25 and the bottom 21 constitutes a reservoir chamber 18, similar to the space between the inner cylinder 15 and the outer cylinder 16.

[0016] The rod guide 26 is annular and is provided at the other axial end of the inner cylinder 15 and the outer cylinder 16. The rod guide 26 is provided on the opening 22 side of the cylinder 17. The rod guide 26 has a large diameter portion 35 on one axial side of the outer periphery, and a small diameter portion 36 on the other axial side of the outer periphery. The outer diameter of the large diameter portion 35 is larger than the outer diameter of the small diameter portion 36. Thus, the outer periphery of the rod guide 26 has a stepped shape. The rod guide 26 fits into the inner periphery of the opening 22 side of the body portion 20 of the outer cylinder 16 at the large diameter portion 35, with the small diameter portion 36 located closer to the bottom 21 than the large diameter portion 35.

[0017] One axial end of the inner cylinder 15 is fitted into the small diameter portion 32 on the outer periphery of the valve base 25. One axial end of the inner cylinder 15 is placed on the bottom 21 of the outer cylinder 16 via the valve base 25. The other axial end of the inner cylinder 15 is fitted into the small diameter portion 36 of the rod guide 26. This other end of the inner cylinder 15 is fitted into the body 20 of the outer cylinder 16 via the rod guide 26. In this state, the inner cylinder 15 is positioned axially and radially with respect to the outer cylinder 16.

[0018] The shock absorber 11 is provided with an annular rod seal 41. The rod seal 41 is provided on the opposite side of the bottom 21 of the rod guide 26 in the axial direction of the cylinder 17. This rod seal 41 is also fitted to the inner periphery of the body 20, similar to the rod guide 26. The outer cylinder 16 has a locking portion 43 formed at the end opposite to the bottom 21 of the body 20. The locking portion 43 is formed by plastically deforming the body 20 inward in the radial direction by crimping such as curling. The rod seal 41 is sandwiched between the locking portion 43 and the rod guide 26. At that time, the rod seal 41 is pressed against the inner periphery of the body 20 by the rod guide 26. As a result, the rod seal 41 closes the opening 22 of the outer cylinder 16. Specifically, the rod seal 41 is an oil seal.

[0019] The shock absorber 11 includes a piston 45. The piston 45 is slidably fitted in the inner tube 15 of the cylinder 17. The piston 45 divides the inner tube 15 into two chambers, a first chamber 48 and a second chamber 49. The first chamber 48 is provided between the piston 45 and the rod guide 26 in the inner tube 15. The second chamber 49 is provided between the piston 45 and the valve base 25 in the inner tube 15. The second chamber 49 is divided from the reservoir chamber 18 by the valve base 25. In the cylinder 17, oil L as a working fluid is sealed in the first chamber 48 and the second chamber 49. In the cylinder 17, gas G and oil L as a working fluid are sealed in the reservoir chamber 18.

[0020] The shock absorber 11 includes a piston rod 50. One axial end of the piston rod 50 is inserted into the cylinder 17. The piston rod 50 is connected to the piston 45 at one end. The piston rod 50 has an axial middle portion passing through the rod guide 26 and the rod seal 41. The piston rod 50 has an axial other end extending to the outside of the cylinder 17. The piston rod 50 is made of metal and passes through the first chamber 48. The piston rod 50 does not pass through the second chamber 49. Therefore, the first chamber 48 is a rod side chamber through which the piston rod 50 passes. The second chamber 49 is a bottom side chamber on the bottom 21 side of the cylinder 17. The piston rod 50 has a portion extending from the cylinder 17 to the outside connected to the vehicle body side.

[0021] The piston rod 50 has a main shaft portion 51 and a mounting shaft portion 52 . The mounting shaft portion 52 has an outer diameter smaller than the outer diameter of the main shaft portion 51. The mounting shaft portion 52 side of the piston rod 50 is inserted into the cylinder 17.

[0022] The piston rod 50 has a main shaft portion 51 passing through the rod guide 26 and the rod seal 41. The rod guide 26 and the rod seal 41 are provided on the portion of the cylinder 17 from which the piston rod 50 extends. The rod guide 26 slidably supports the piston rod 50. The piston rod 50 is guided by the rod guide 26 at the outer peripheral surface of the main shaft portion 51. The piston rod 50 moves axially together with the piston 45 relative to the cylinder 17. During the extension stroke of the shock absorber 11, in which the piston rod 50 increases the amount of protrusion from the cylinder 17, the piston 45 moves toward the first chamber 48. During the compression stroke of the shock absorber 11, in which the piston rod 50 decreases the amount of protrusion from the cylinder 17, the piston 45 moves toward the second chamber 49.

[0023] The rod seal 41 is provided on the side where the piston rod 50 of the cylinder 17 extends, i.e., on the opening 22 side of the outer cylinder 16. The rod seal 41, together with the rod guide 26, seals between the body 20 of the outer cylinder 16 and the main shaft portion 51 of the piston rod 50, and prevents the oil L in the inner cylinder 15 and the gas G and oil L in the reservoir chamber 18 from leaking out to the outside.

[0024] A passage 55 and a passage 56 are formed in the piston 45. Both the passage 55 and the passage 56 pass through the piston 45 in the axial direction. The passages 55, 56 can communicate between the first chamber 48 and the second chamber 49. The shock absorber 11 includes a disc valve 57 and a disc valve 58. The disc valve 57 is provided on the side of the piston 45 opposite the bottom 21 in the axial direction. The disc valve 57 is annular, and closes the passage 55 by abutting against the piston 45. The disc valve 58 is provided on the bottom 21 side of the piston 45 in the axial direction. The disc valve 58 is annular, and closes the passage 56 by abutting against the piston 45. The disc valves 57, 58 are attached to the piston rod 50 together with the piston 45.

[0025] When the piston rod 50 moves to the compression side increasing the amount of penetration into the inner cylinder 15 and the outer cylinder 16 and the piston 45 moves in the direction narrowing the second chamber 49, the pressure in the second chamber 49 becomes higher than the pressure in the first chamber 48. Then, the disc valve 57 opens the passage 55 to allow the oil L in the second chamber 49 to flow into the first chamber 48. At that time, the disc valve 57 generates a damping force.

[0026] When the piston rod 50 moves to the extension side, increasing the amount of protrusion from the inner cylinder 15 and the outer cylinder 16, and the piston 45 moves in a direction narrowing the first chamber 48, the pressure in the first chamber 48 becomes higher than the pressure in the second chamber 49. Then, the disc valve 58 opens the passage 56 to allow the oil L in the first chamber 48 to flow into the second chamber 49. At that time, the disc valve 58 generates a damping force.

[0027] A fixed orifice (not shown) is formed in at least one of the piston 45 and the disc valve 57. This fixed orifice allows communication between the first chamber 48 and the second chamber 49 via the passage 55 even when the disc valve 57 is in a state where the passage 55 is most blocked.

[0028] A fixed orifice (not shown) is formed in at least one of the piston 45 and the disc valve 58. This fixed orifice allows communication between the first chamber 48 and the second chamber 49 via the passage 56 even when the disc valve 58 is in a state where the passage 56 is most blocked.

[0029] As described above, the body valve 30 has the valve base 25 that separates the second chamber 49 from the reservoir chamber 18. The valve base 25 is a seamless, one-piece molded product made of metal. As shown in FIG. 2, the valve base 25 has a base portion 71 and a leg portion 72.

[0030] The base portion 71 is in the shape of a perforated disk. The leg 72 is cylindrical and extends from the outer periphery of the base 71 to one side in the axial direction of the base. A part of the large diameter portion 31 is formed in the leg 72, and the remaining part of the large diameter portion 31 and the small diameter portion 32 are formed in the base 71. The above-mentioned passage groove 33 penetrating the leg 72 in the radial direction is formed in the leg 72. The passage groove 33 opens at the end of the leg 72 opposite the base 71 in the axial direction. A plurality of passage grooves 33 are formed in the leg 72 at intervals in the circumferential direction. The valve base 25 is placed on the bottom 21 of the outer cylinder 16 at the end of the leg 72 opposite the base 71 in the axial direction. At this time, the valve base 25 is positioned in the radial direction with respect to the outer cylinder 16.

[0031] A through hole 81 is formed in the radial center of the base portion 71 of the valve base 25. The base portion 71 has a base main body portion 82, an inner sheet 83, and an inner sheet 84.

[0032] The inner sheet 83 is annular, and protrudes from the entire circumference of the edge portion of the base main body 82 on the through hole 81 side in the radial direction to the opposite side to the leg portion 72 in the axial direction of the base main body 82 .

[0033] The inner sheet 84 is annular, and protrudes from the entire circumference of the edge of the base main body 82 on the through-hole 81 side in the radial direction toward the leg 72 in the axial direction of the base main body 82.

[0034] The base portion 71 has an outer sheet 86 and an intermediate sheet 87 . The outer sheet 86 is annular, and protrudes from a portion of the base main body 82 that is radially outward of the inner sheet 83 toward the opposite side to the leg portion 72 in the axial direction of the base main body 82 .

[0035] The intermediate sheet 87 is annular, and protrudes from a position between the outer sheet 86 and the inner sheet 83 in the radial direction of the base main body 82 toward the opposite side to the leg portion 72 in the axial direction of the base main body 82 .

[0036] The base portion 71 also has an outer sheet 88. The outer sheet 88 is annular, and protrudes from a position between the leg portion 72 and the inner sheet 84 in the radial direction of the base main body portion 82 toward the leg portion 72 in the axial direction of the base main body portion 82.

[0037] The base portion 71 also has a protrusion 89. The protrusion 89 protrudes from the base main body portion 82 on the same side as the outer sheet 88 in the axial direction of the base main body portion 82. The protrusion 89 extends from the outer sheet 88 inward in the radial direction of the outer sheet 88. In the axial direction of the base main body portion 82, the protrusion 89 protrudes to a lower height from the base main body portion 82 than the protrusion height of the outer sheet 88 from the base main body portion 82. A plurality of protrusions 89 of the same shape are formed on the base portion 71 at equal intervals in the circumferential direction of the base portion 71.

[0038] An outer passage hole 91 penetrating the base main body 82 in the axial direction is formed in the base main body 82 between the outer sheet 86 and the intermediate sheet 87 in the radial direction. The base main body 82 is provided with a plurality of outer passage holes 91 at equal intervals in the circumferential direction of the base main body 82. The plurality of outer passage holes 91 are disposed between the outer sheet 88 and the leg portion 72 in the radial direction of the base main body 82. The plurality of outer passage holes 91 allow communication between the second chamber 49 and the reservoir chamber 18.

[0039] An inner passage hole 92 penetrating the base main body portion 82 in the axial direction is formed in the base main body portion 82 between the inner sheet 83 and the intermediate sheet 87 in the radial direction. The base main body portion 82 is provided with a plurality of inner passage holes 92 at equal intervals in the circumferential direction of the base main body portion 82. The plurality of inner passage holes 92 are disposed between the outer sheet 88 and the inner sheet 84 in the radial direction of the base main body portion 82. The plurality of inner passage holes 92 allow communication between the second chamber 49 and the reservoir chamber 18.

[0040] The body valve 30 has a pin member 101 that is inserted into the through hole 81 of the valve base 25. The pin member 101 is a bolt, and has a head 102 and a shaft portion 103 whose outer diameter is smaller than the outer diameter of the head 102.

[0041] The head 102 is engageable with a fastening tool. The shaft portion 103 is cylindrical and extends from the radial center of the head 102 to one side along the axial direction of the head 102. A male thread 104 is formed on the outer periphery of the shaft portion 103 on the side opposite to the head 102 in the axial direction.

[0042] The body valve 30 has, in order from the valve base 25 side in the axial direction, one valve disc 110, one valve disc 111, one disc 112, one spring disc 113, and one regulating disc 114 on the side opposite the bottom 21 of the valve base 25 in the axial direction. The valve discs 110, 111, disc 112, spring disc 113, and regulating disc 114 are all made of metal. The valve discs 110, 111, and disc 112 are all in the form of a circular flat plate with a certain thickness and a hole into which the shaft portion 103 of the pin member 101 can be fitted.

[0043] The valve disc 110 has an outer diameter slightly larger than the outer diameter of the outer seat 86 of the valve base 25. The valve disc 110 is flexible and abuts against the inner seat 83, the outer seat 86 and the intermediate seat 87 to close the outer passage hole 91. The valve disc 110 has a passage hole 121 penetrating the valve disc 110 in the axial direction between the inner seat 83 and the intermediate seat 87 in the radial direction. The passage hole 121 is an elongated hole extending in the circumferential direction of the valve disc 110. The valve disc 110 has a notch 122 formed on the outer periphery. The notch 122 crosses the contact portion of the outer seat 86 with the valve disc 110 in the radial direction. An orifice 123 is formed inside the notch 122.

[0044] The valve disc 111 has an outer diameter equal to that of the valve disc 110. The valve disc 111 is flexible and comes into contact with the valve disc 110. The valve disc 111 is formed with a passage hole 125 penetrating the valve disc 111 in the axial direction between the radial inner sheet 83 and the radial outer sheet 86. The valve disc 111 is formed with a plurality of passage holes 125 at equal intervals in the circumferential direction of the valve disc 111. In the radial direction of the valve discs 110, 111, the passage hole 125 is offset from the notch 122 and partially overlaps with the passage hole 121. The communicating portion between the passage hole 121 and the passage hole 125 is an orifice 128.

[0045] The disk 112 has an outer diameter equal to the outer diameter of the inner seat 83 of the valve base 25 , and is entirely disposed radially inward of the passage hole 125 of the valve disk 111 .

[0046] The spring disc 113 has a base portion 131 and a spring plate portion 132 . The base plate portion 131 is a circular flat plate with a hole of a constant thickness, and the shaft portion 103 of the pin member 101 can be fitted inside the base plate portion 131. The base plate portion 131 has an outer diameter slightly larger than the outer diameter of the disk 112.

[0047] The spring plate portion 132 extends radially outward from the outer peripheral edge of the base plate portion 131. The spring plate portion 132 is flexible. A plurality of spring plate portions 132 are formed in the spring disk 113 at equal intervals in the circumferential direction of the base plate portion 131. The spring plate portions 132 are inclined with respect to the base plate portion 131 so as to move away from the base plate portion 131 in the axial direction of the base plate portion 131 toward the radially outer side of the base plate portion 131. All of the plurality of spring plate portions 132 extend to the same side of the base plate portion 131 in the axial direction of the base plate portion 131. The spring disk 113 abuts against the disk 112 at the base plate portion 131, and the plurality of spring plate portions 132 extend from the base plate portion 131 toward the valve disk 111 in the axial direction and abut against an annular portion of the valve disk 111 that is outside the passage hole 125 in the radial direction.

[0048] The regulating disc 114 is thicker and more rigid than the valve discs 110, 111 and the spring disc 113. The regulating disc 114 has a main plate portion 141 and an outer circumferential step portion 142. The main plate portion 141 is a circular flat plate with a hole and a constant thickness, and the shaft portion 103 of the pin member 101 can be fitted inside the main plate portion 141.

[0049] The outer peripheral step 142 is annular, and protrudes radially outward from the entire outer periphery of the main plate 141. The outer peripheral step 142 is formed slightly shifted to one side in the axial direction relative to the main plate 141. The regulating disk 114 abuts against the base plate 131 of the spring disk 113 at the main plate 141, and the outer peripheral step 142 protrudes axially toward the valve disk 111 side relative to the main plate 141. A passage hole 143 penetrating the main plate 141 in the axial direction is formed in the main plate 141 at a predetermined radial intermediate position. A plurality of passage holes 143 are formed in the main plate 141 at equal intervals in the circumferential direction of the main plate 141. The passage hole 143 constantly connects the second chamber 49 to the inner passage hole 92 of the valve base 25 via the gap between the spring plate portions 132 of the spring disc 113, the passage hole 125 of the valve disc 111, and the passage hole 121 of the valve disc 110.

[0050] As shown in FIG. 3, the body valve 30 has, on the axial leg portion 72 side of the base portion 71 of the valve base 25, in order from the base portion 71 side in the axial direction, one disc 151, one opening / closing disc 152, one conical spring 153, one valve disc 154, one valve disc 155, one valve disc 156, multiple valve discs, specifically three valve discs 157, one disc 158, and one disc 159.

[0051] The disks 151, 158, the opening / closing disk 152, the conical spring 153, the valve disks 154 to 157, and the disk 159 are all made of metal. The disks 151, 158, the valve disks 154 to 157, and the disk 159 are all in the form of a circular flat plate with a certain thickness and a hole, into which the shaft portion 103 of the pin member 101 can be fitted. The opening / closing disk 152 and the conical spring 153 are all in the form of annular rings, into which the shaft portion 103 of the pin member 101 can be fitted.

[0052] The disc 151 has an outer diameter that is slightly smaller than the outer diameter of the inner seat 84 of the valve base 25 .

[0053] The opening / closing disc 152 is in a natural state before being assembled into the body valve 30, and is a circular flat plate with holes having a certain thickness. The opening / closing disc 152 is flexible. The opening / closing disc 152 has an outer diameter larger than the outer diameter of the disc 151. The opening / closing disc 152 has an outer diameter that does not contact the multiple protrusions 89 of the valve base 25.

[0054] The conical spring 153 is formed by pressing a single flat plate material. The conical spring 153 has a base portion 161 and an outer peripheral tapered plate portion 162. The conical spring 153 is flexible.

[0055] When the conical spring 153 is in its natural state before being assembled into the body valve 30, the base plate portion 161 is in the shape of a circular plate with a hole of a constant thickness. A passage hole 163 penetrating the base plate portion 161 in the axial direction of the base plate portion 161 is formed in the base plate portion 161 at a position whose diameter is larger than the outer diameter of the disk 151 and smaller than the outer diameter of the opening / closing disk 152. A plurality of passage holes 163 are formed in the base plate portion 161 at equal intervals in the circumferential direction of the base plate portion 161.

[0056] The outer peripheral tapered plate portion 162 widens in a tapered shape from the outer peripheral edge portion of the base plate portion 161. The outer peripheral tapered plate portion 162 becomes larger in diameter as it moves away from the flat base plate portion 161 in the axial direction of the base plate portion 161. The outer peripheral tapered plate portion 162 is annular, and is formed around the entire circumference of the base plate portion 161.

[0057] The boundary between the base plate portion 161 and the outer peripheral tapered plate portion 162 of the conical spring 153 forms a corner portion 164. The corner portion 164 is provided around the entire circumference of the conical spring 153 and has a circular shape.

[0058] The valve disc 154 has an outer diameter slightly larger than the outer diameter of the outer seat 88 of the valve base 25. The valve disc 154 is flexible and abuts against the conical spring 153 and the outer seat 88. The valve disc 154 has a notch 171 formed on the outer periphery. The notch 171 crosses the contact portion of the outer seat 88 with the valve disc 154 in the radial direction. The valve disc 154 has a plurality of notches 171 formed at equal intervals in the circumferential direction of the valve disc 154. The valve disc 154 has a passage hole 172 penetrating the valve disc 154 in the axial direction of the valve disc 154. The passage hole 172 is provided at a position radially inward of the inscribed circle of the plurality of notches 171 of the valve disc 154. The passage hole 172 is an arc-shaped long hole extending in the circumferential direction of the valve disc 154.

[0059] The valve disc 155 has an outer diameter equal to that of the valve disc 154. The valve disc 155 is flexible. A passage hole 181 is formed in the valve disc 155, penetrating the valve disc 155 in the axial direction of the valve disc 155. The passage hole 181 is provided at a position overlapping with the passage hole 172 of the valve disc 154 in the radial direction of the valve discs 154, 155. The passage hole 181 is an arc-shaped elongated hole extending in the circumferential direction of the valve disc 155.

[0060] The valve disc 156 has an outer diameter equal to the outer diameters of the valve discs 154, 155. The valve disc 156 is flexible. A notch 191 is formed on the outer periphery of the valve disc 156. A passage hole 192 is formed in the valve disc 156, penetrating the valve disc 156 in the axial direction of the valve disc 156. The passage hole 192 is provided at a position overlapping with the passage hole 181 of the valve disc 155 in the radial direction of the valve discs 155, 156. The passage hole 192 is an arc-shaped elongated hole extending in the circumferential direction of the valve disc 154. The notch 191 communicates with the passage hole 192.

[0061] In each case, the passage holes 172, 181, 192, which are shaped like elongated holes that are long in the circumferential direction of the valve discs 154-156, overlap in position in the radial direction of the valve discs 154-156. This ensures that the passage holes 172, 181, 192 have a sufficient overlapping area regardless of the phase of the valve discs 154-156.

[0062] The multiple valve discs 157 have an outer diameter equal to the outer diameter of the valve discs 154 to 156. The valve discs 157 are flexible. The disc 158 has an outer diameter smaller than the outer diameters of the valve discs 154-157.

[0063] The disc 159 has an outer diameter larger than the outer diameter of the disc 158 and slightly smaller than the outer diameters of the valve discs 154-157.

[0064] When assembling the body valve 30, the pin member 101 is stacked on the head 102 in the order of disc 159, disc 158, the multiple valve discs 157, valve disc 156, valve disc 155, valve disc 154, the conical spring 153, the opening / closing disc 152, disc 151, the valve base 25, the valve disc 110, valve disc 111, disc 112, the spring disc 113, and the regulating disc 114 shown in FIG. 2, with the shaft portion 103 of the pin member 101 fitted inside each of them.

[0065] At this time, the conical spring 153 shown in Fig. 3 is oriented so that the corner portion 164 is located on the opposite side to the valve disc 154. At this time, the valve base 25 is oriented so that the inner seat 84 abuts against the disc 151. At this time, the spring disc 113 shown in Fig. 2 is oriented so that the spring plate portion 132 abuts against the valve disc 111. At this time, the regulating disc 114 is oriented so that the outer circumferential step portion 142 protrudes from the main plate portion 141 towards the valve disc 111 in the axial direction.

[0066] In this state, the nut 201 is screwed onto the male thread 104 of the pin member 101 protruding beyond the main plate portion 141 of the regulating disc 114. As a result, at least the inner circumferential sides of the disc 159, disc 158, the multiple valve discs 157, valve disc 156, valve disc 155, valve disc 154, conical spring 153, open / close disc 152, disc 151, valve base 25 shown in Fig. 3, and the valve disc 110, valve disc 111, disc 112, spring disc 113, and regulating disc 114 shown in Fig. 2 are clamped to the head 102 of the pin member 101 and the nut 201.

[0067] As shown in FIG. 3, when the conical spring 153 is assembled in the body valve 30, the inner peripheral portion of the base plate portion 161 of the conical spring 153 becomes flat, and the outer peripheral portion of the base plate portion 161 is deformed in a tapered shape so that it moves away from the valve disc 154 in the axial direction toward the radially outward direction. In this state, the conical spring 153 has an outer peripheral tapered plate portion 162 tapered so that it moves closer to the valve disc 154 in the axial direction toward the radially outward direction, and the tip portion of the outer peripheral tapered plate portion 162 abuts against the valve disc 154. At that time, the outer peripheral tapered plate portion 162 of the conical spring 153 abuts against the annular portion between the notch 171 and the passage hole 172 in the radial direction of the valve disc 154 over the entire circumference. Therefore, the conical spring 153 is provided so as to cover the passage hole 172 of the valve disc 154. In this state, the conical spring 153 has the passage hole 163 entirely overlapped with the passage hole 172 of the valve disc 154 in the radial direction.

[0068] When assembled into the body valve 30, the opening / closing disc 152 has an inner peripheral portion that is flat. In this state, the opening / closing disc 152 has an outer peripheral portion that is pressed by the outer peripheral portion of the base plate portion 161 of the conical spring 153, and is deformed into a tapered shape so that the radially outward portion moves away from the valve disc 154 in the axial direction. This causes the opening / closing disc 152 to come into surface contact with the base plate portion 161 of the conical spring 153 due to its elastic force. As a result, the opening / closing disc 152 covers the entirety of the multiple passage holes 163 of the conical spring 153, closing the multiple passage holes 163.

[0069] The body valve 30 thus assembled is placed on the bottom 21 of the outer cylinder 16 with the small diameter portion 32 fitted to one axial end of the inner cylinder 15 as shown in Fig. 2. As a result, the body valve 30 is in communication with the cylinder 17.

[0070] In the body valve 30, a first passage 211 is formed between the intermediate seat 87 and the outer seat 86 of the valve base 25 and the inside of the multiple outer passage holes 91, which can communicate between the reservoir chamber 18 and the second chamber 49. In the body valve 30, the valve discs 110, 111, the disc 112, and the spring disc 113 form a first damping valve 212 that opens and closes the first passage 211. In the first passage 211, a flow of oil L, which is a working fluid, is generated by the movement of the piston 45 shown in FIG. 1 in one direction, that is, the extension direction. The first damping valve 212 shown in FIG. 2 applies resistance to the flow of oil L from the reservoir chamber 18 on the upstream side of the first passage 211 to the second chamber 49 on the downstream side. A first damping valve 212 and an orifice 123 are provided in the first passage 211 and constitute a first extension-side damping force generating mechanism 215 that suppresses the flow of oil liquid L flowing inside the first passage 211 and generates a damping force.

[0071] In the body valve 30, the orifice 128 provided in the first damping valve 212, the space between the base main body portion 82, the inner seat 83, and the intermediate seat 87 of the valve base 25, and the inside of the multiple inner passage holes 92 form a second passage 221. The second passage 221 includes a variable chamber 220 surrounded by the base main body portion 82, the inner seat 84, the outer seat 88, and the multiple protrusions 89 of the valve base 25 shown in Fig. 3, the disk 151, the opening / closing disk 152, the conical spring 153, and the valve disk 154. The second passage 221 can communicate between the second chamber 49 shown in Fig. 2 and the reservoir chamber 18.

[0072] The body valve 30 is a second damping disc valve 222 that opens and closes a second passage 221 by the valve discs 154-157 shown in Fig. 3 moving away from and into contact with the outer seat 88. Therefore, the second damping disc valve 222 is provided in the body valve 30. In the second passage 221, a flow of oil L, which is a working fluid, is generated by the movement of the piston 45 shown in Fig. 1 in the contraction direction, which is the other direction. The second damping disc valve 222 shown in Fig. 2 applies resistance to the flow of oil L from the second chamber 49 on the upstream side of the second passage 221 to the reservoir chamber 18 on the downstream side.

[0073] In the body valve 30, the inside of the notch 171 of the valve disc 154 of the second damping disc valve 222 shown in Fig. 3 constitutes the third passage 231. The third passage 231 is an orifice that constantly communicates the variable chamber 220 and the reservoir chamber 18. The third passage 231 is provided in the second passage 221. The third passage 231 allows the second passage 221 to constantly communicate the reservoir chamber 18 and the second chamber 49 shown in Fig. 2. In other words, the third passage 231 constantly communicates the upstream reservoir chamber 18 and the downstream second chamber 49 when the piston 45 shown in Fig. 1 moves in the extension direction, and constantly communicates the upstream second chamber 49 and the downstream reservoir chamber 18 when the piston 45 moves in the contraction direction. The second damping disc valve 222 and a third passage 231, which is an orifice, shown in Figure 3 are provided in the second passage 221 and constitute a compression-side second damping force generating mechanism 225 that suppresses the flow of oil liquid L flowing through the second passage 221 and generates a damping force.

[0074] In the body valve 30, the inside of the notch 191 and the passage hole 192 of the valve disc 156 of the second damping disc valve 222, the inside of the passage hole 181 of the valve disc 155, and the inside of the passage hole 172 of the valve disc 154 form a fourth passage 241 (communication passage) that always communicates with the upstream reservoir chamber 18 when the piston 45 moves in the extension direction shown in Fig. 1. In other words, the second damping disc valve 222 has the fourth passage 241. Note that a part of the fourth passage 241 may be provided in the pin member 101.

[0075] In the fourth passage 241, the inside of the notch 191 of the valve disc 156 serves as an orifice 242. In the fourth passage 241, the inside of the passage hole 192 of the valve disc 156, the inside of the passage hole 181 of the valve disc 155, and the inside of the passage hole 172 of the valve disc 154 serve as an intermediate chamber 243.

[0076] The third passage 231 and the fourth passage 241 are provided in the second damping disc valve 222. The third passage 231 and a part of the fourth passage 241 are formed in a valve disc 154 of the second damping disc valve 222 that is seated on the outer seat 88.

[0077] The body valve 30 includes the base main body portion 82, inner seat 84, outer seat 88 and multiple protrusions 89 of the valve base 25, the disc 151, the opening / closing disc 152, the belleville spring 153 and the valve disc 154, which form a pressure accumulation mechanism 251 including a variable chamber 220.

[0078] In the pressure accumulation mechanism 251, a portion surrounded by the opening / closing disc 152, the conical spring 153, and the valve disc 154 constitutes a variable chamber 252. In other words, the pressure accumulation mechanism 251 has the variable chamber 252. The variable chamber 252 is partitioned from the variable chamber 220 of the second passage 221 by the conical spring 153 and the opening / closing disc 152. The conical spring 153 and the opening / closing disc 152 constitute a partition member 255 that partitions the variable chamber 252 and the variable chamber 220. The variable chamber 252 communicates with the fourth passage 241.

[0079] The partitioning member 255 moves in response to a pressure change in the upstream reservoir chamber 18 or the downstream second chamber 49 when the piston 45 shown in Fig. 1 moves in the extension direction. The partitioning member 255 shown in Fig. 3 moves in response to a pressure change in the upstream second chamber 49 or the downstream reservoir chamber 18 when the piston 45 shown in Fig. 1 moves in the contraction direction. The partitioning member 255 shown in Fig. 3 is composed of a conical spring 153. During the extension stroke of the piston 45 shown in Fig. 1, the partitioning member 255 makes the variable chamber 252 formed between the valve disc 154 shown in Fig. 3 larger and the variable chamber 220 smaller, while during the contraction stroke of the piston 45 shown in Fig. 1, the variable chamber 220 shown in Fig. 3 is larger and the variable chamber 252 is smaller.

[0080] When the conical spring 153 deforms in a direction to increase the variable chamber 252, the corner 164 of the conical spring 153 comes into contact with the protruding portion 89 of the valve base 25, and further deformation is suppressed. When the conical spring 153 deforms in a direction to increase the variable chamber 220 ... The outer peripheral tapered plate portion 162 of the conical spring 153 always comes into contact with the valve disc 154 over the entire circumference, thereby sealing between the variable chamber 252 and the variable chamber 220. Here, since the protruding portions 89 are formed discontinuously in the circumferential direction of the valve base 25, the second passage 221 is not blocked even if the conical spring 153 comes into contact with the protruding portion 89 at the corner 164.

[0081] When the pressure difference between the upstream variable chamber 252 shown in Fig. 3 and the downstream variable chamber 220 reaches a predetermined value during movement of the piston 45 shown in Fig. 1 in the extension direction, the opening / closing disk 152 moves away from the conical spring 153 to open the passage hole 163 of the conical spring 153 and communicate the variable chamber 252 with the variable chamber 220, i.e., the second chamber 49 shown in Fig. 2. The passage hole 163 of the conical spring 153 and the opening / closing disk 152 shown in Fig. 3 constitute a relief mechanism 258 that relieves the inside of the variable chamber 252 after the pressure difference between the upstream variable chamber 252 shown in Fig. 3 and the downstream variable chamber 220 reaches a predetermined value during movement of the piston 45 shown in Fig. 1 in the extension direction. In other words, the partition member 255 is provided with the relief mechanism 258.

[0082] The pressure accumulator mechanism 251 has a variable chamber 252 that communicates with the fourth passage 241. The variable chamber 252 is partitioned from the variable chamber 220 of the second passage 221 by a partition member 255 shown in Fig. 3 that moves in response to a pressure change in the upstream reservoir chamber 18 or the downstream second chamber 49 when the piston 45 shown in Fig. 1 moves in the extension direction.

[0083] The variable chambers 220, 252 are formed by the second damping disc valve 222. The variable chambers 220, 252 are disposed on the second damping disc valve 222 so as to overlap with the second damping disc valve 222 in the axial direction of the second damping disc valve 222. The pressure accumulator mechanism 251 including the variable chambers 220, 252 is disposed on the second damping disc valve 222 so as to overlap with the second damping disc valve 222 in the axial direction.

[0084] The hydraulic circuit diagram of the body valve 30 described above is as shown in FIG. The body valve 30 is provided with a first damping force generating mechanism 215 on the extension side, which includes a first damping valve 212 and an orifice 123, in a first passage 211 on the extension side that communicates the reservoir chamber 18 and the second chamber 49. The body valve 30 is provided with a second damping force generating mechanism 225 on the compression side, which includes an orifice 128, a second damping disc valve 222, and a third passage 231, in a second passage 221 that communicates the second chamber 49 and the reservoir chamber 18. The body valve 30 is provided with a variable chamber 220 of a pressure accumulation mechanism 251 between the orifice 128 of the second passage 221 and the second damping force generating mechanism 225. The body valve 30 is provided with a variable chamber 252 of the pressure accumulation mechanism 251 that communicates with the reservoir chamber 18 via an intermediate chamber 243 and an orifice 242 of a fourth passage 241. In addition, the body valve 30 is provided with a relief mechanism 258 between the variable chamber 252 of the pressure accumulator mechanism 251 and the variable chamber 220, which regulates the flow of oil liquid L from the variable chamber 220 to the variable chamber 252, while allowing the flow of oil liquid L from the variable chamber 252 to the variable chamber 220.

[0085] Next, the main operation of the body valve 30 will be described.

[0086] During the extension stroke in which the piston rod 50 moves to the extension side, when only the extension-side first damping force generating mechanism 215 is operating, in a low-speed range where the moving speed of the piston 45 (hereinafter referred to as the piston speed) is slower than a predetermined value, the oil L from the reservoir chamber 18 flows mainly into the second chamber 49 via the orifice 123 of the extension-side first passage 211. As a result, a damping force with orifice characteristics (where the damping force is approximately proportional to the square of the piston speed) is generated. The characteristic of the damping force relative to the piston speed in the low-speed range is that the rate of increase of the damping force becomes relatively high as the piston speed increases.

[0087] Furthermore, during the extension stroke, in a high speed range where the piston speed is equal to or higher than a predetermined value, the oil L from the reservoir chamber 18 opens the first damping valve 212 in the first passage 211 on the extension side and flows into the second chamber 49. This generates a damping force with valve characteristics (the damping force is approximately proportional to the piston speed). Therefore, in the high speed range of the piston speed, the damping force increase rate with respect to the increase in the piston speed is slightly lower than in the low speed range described above.

[0088] During the compression stroke in which the piston rod 50 moves toward the compression side, when only the second damping force generating mechanism 225 on the compression side is operating, in a low-speed region where the piston speed is slower than a predetermined value, the oil L from the second chamber 49 flows into the reservoir chamber 18 mainly via the third passage 231, which is an orifice of the second passage 221. As a result, a damping force with orifice characteristics (the damping force is approximately proportional to the square of the piston speed) is generated. Therefore, the characteristic of the damping force relative to the piston speed in the low-speed region is that the rate of increase of the damping force is relatively high as the piston speed increases.

[0089] Furthermore, during the compression stroke, in a high speed range where the piston speed is equal to or higher than a predetermined value, the oil L from the second chamber 49 opens the second damping disc valve 222 in the second passage 221 and flows into the reservoir chamber 18. This generates a damping force with valve characteristics (the damping force is approximately proportional to the piston speed). Therefore, in the high speed range of the piston speed, the damping force characteristic with respect to the piston speed is such that the rate of increase in the damping force with respect to the increase in the piston speed is slightly lower than in the low speed range described above.

[0090] The above is the case where only the first damping force generating mechanism 215 and the second damping force generating mechanism 225 are in operation. However, in the first embodiment, the pressure accumulation mechanism 251 varies the damping force according to the piston frequency during the extension stroke and compression stroke described above, even if the piston speed is the same.

[0091] That is, during the extension stroke, the pressure in the second chamber 49 becomes lower than the pressure in the reservoir chamber 18, and the oil L in the reservoir chamber 18 is introduced into the first passage 211 and flows into the second chamber 49 via the first damping force generating mechanism 215. In addition, the oil L in the reservoir chamber 18 is introduced into the variable chamber 252 of the pressure accumulating mechanism 251 from the fourth passage 241, deforming the partition member 255 and expanding the variable chamber 252. At that time, the oil L in the variable chamber 220 that is being contracted is discharged into the second chamber 49 via the second passage 221.

[0092] During the extension stroke when the piston speed is low and the piston frequency is low, the stroke of the piston 45 is large, so that in the early stage of the introduction of the oil L from the reservoir chamber 18 to the variable chamber 252 through the fourth passage 241, the partition member 255 is largely deflected, and the conical spring 153 comes into contact with the protruding portion 89 of the valve base 25 at the corner portion 164, suppressing further deformation. As a result, the variable chamber 252 is in a state where the increase in volume is suppressed, and the variable chamber 252 cannot absorb the increase in the amount of oil L introduced. Then, the force of the oil L in the reservoir chamber 18 pushing the first damping valve 212 in the opening direction increases. As a result, the first damping valve 212 opens, and the oil L flows into the second chamber 49 through the first passage 211. Therefore, during the extension stroke when the piston speed is low and the piston frequency is low, the damping force characteristics are the same as when the pressure accumulator mechanism 251 is not present.

[0093] On the other hand, even when the piston speed is low and the piston frequency is high and equal to or higher than the predetermined value, the stroke of the piston 45 is small during the extension stroke, and therefore the volume of the oil L introduced from the reservoir chamber 18 through the fourth passage 241 into the variable chamber 252 is small. Therefore, the partition member 255 has a small amount of deflection and does not come into contact with the protruding portion 89 of the valve base 25, or can be deformed even if it comes into contact with the protruding portion 89. Therefore, most of the increase in the oil L introduced from the reservoir chamber 18 through the fourth passage 241 into the variable chamber 252 is absorbed by the deflection of the partition member 255. Then, the force of the oil L in the reservoir chamber 18 pushing the first damping valve 212 in the opening direction is suppressed more than when the piston frequency is low and lower than the predetermined value, and the damping force is lower and softer than when the frequency is low.

[0094] Therefore, in the extension stroke, when the piston speed is low and the piston frequency is high and equal to or higher than a predetermined value, the damping force characteristics are softer and the damping force is lower than that when the piston frequency is low and equal to or higher than a predetermined value. This suppresses a sudden change in hydraulic pressure when the first damping valve 212 opens during the extension stroke when the piston speed is low and the piston frequency is high and equal to or higher than a predetermined value, which is when abnormal noise is likely to occur, and makes it possible to reduce the acceleration of the piston rod 50 (hereinafter referred to as rod acceleration), thereby suppressing the occurrence of abnormal noise.

[0095] In addition, when the piston speed is high, that is, equal to or higher than a predetermined value, the partition member 255 is largely deflected, and the conical spring 153 comes into contact with the protruding portion 89 of the valve base 25 at the corner portion 164, and in a state in which further deformation is suppressed, the opening / closing disc 152 is deformed and separated from the conical spring 153. In other words, the relief mechanism 258 opens. This causes the oil L in the variable chamber 252 to flow into the second chamber 49 through the second passage 221 including the variable chamber 220. This relief function can reduce the pressure load on the conical spring 153 and ensure durability. At the same time, the amount of oil L moving to the second chamber 49 during the extension stroke can be increased, so that excessive decompression of the second chamber 49 can be suppressed, and cavitation can be suppressed.

[0096] During the compression stroke, the pressure in the second chamber 49 becomes higher than the pressure in the reservoir chamber 18, and the oil L in the second chamber 49 is introduced into the second passage 221 and flows into the reservoir chamber 18 via the second damping force generating mechanism 225. In addition, the oil L in the second chamber 49 is introduced into the variable chamber 220 of the pressure accumulating mechanism 251, deforming the partition member 255 and expanding the variable chamber 220. At that time, the oil L in the contracting variable chamber 252 is discharged into the reservoir chamber 18 via the fourth passage 241.

[0097] In the compression stroke when the piston frequency is lower than a predetermined value, the stroke of the piston 45 is large, so that in the early stage of the introduction of the oil L from the second chamber 49 to the variable chamber 220, the partition member 255 is largely deflected and the deformation is suppressed by the valve disc 154. As a result, the volume of the variable chamber 220 is in a state of not changing, and the variable chamber 220 cannot absorb the increase in the amount of oil L introduced. Then, the pressure in the variable chamber 220 rises to a high pressure, and the force pushing the second damping disc valve 222 in the opening direction becomes strong. Therefore, the second damping disc valve 222 opens and the oil L flows into the reservoir chamber 18 through the gap with the outer seat 88. Therefore, in the compression stroke when the piston frequency is low and lower than a predetermined value, the damping force characteristic is the same as that in the case where the pressure accumulation mechanism 251 is not present.

[0098] On the other hand, in the compression stroke when the piston frequency is equal to or higher than a predetermined value, the stroke of the piston 45 is small, and therefore the volume of the oil L introduced from the second chamber 49 to the variable chamber 220 is small, and the partition member 255 is easily deformed with a small amount of deflection. Therefore, most of the increase in the oil L introduced from the second chamber 49 to the variable chamber 220 is absorbed by the deflection of the partition member 255. Therefore, the variable chamber 220 is at low pressure, and the opening pressure of the second damping disc valve 222 does not increase. Therefore, when the piston frequency is high, the damping force is lower and softer than when the piston frequency is low.

[0099] Therefore, in the compression stroke, when the piston frequency is a high frequency equal to or higher than a predetermined value, the damping force characteristic is lower and softer than when the piston frequency is a low frequency lower than the predetermined value. This suppresses a sudden change in hydraulic pressure when the second damping disc valve 222 opens during the compression stroke when the piston frequency is a high frequency equal to or higher than a predetermined value, which is likely to cause abnormal noise, and makes it possible to reduce the rod acceleration and suppress the occurrence of abnormal noise.

[0100] The dashed line in Fig. 5 shows the simulation result of the rod acceleration of the shock absorber 11 of the first embodiment equipped with the body valve 30 having the pressure accumulation mechanism 251. The solid line in Fig. 5 shows the simulation result of the rod acceleration of the shock absorber equipped with a body valve of a comparative example of a conventional structure different from the body valve 30 in that the pressure accumulation mechanism 251 and the fourth passage 241 are not provided. The two-dot chain line in Fig. 5 shows the simulation result of the damping force. It can be seen from Fig. 5 that the peak value of the rod acceleration caused by the opening of the first damping valve 212 is lower in the shock absorber 11 of the first embodiment than in the shock absorber of the comparative example.

[0101] The dashed lines in Fig. 6 and Fig. 7 show the simulation results of the damping force when the piston speed of the shock absorber 11 of the first embodiment alone is 0.6 m / s and a low frequency input is applied. The solid lines in Fig. 6 and Fig. 7 show the simulation results of the damping force when the piston speed of the shock absorber of the comparative example alone is 0.6 m / s and a low frequency input is applied.

[0102] It can be seen from Figs. 6 and 7 that the shock absorber 11 of the first embodiment maintains the damping force waveform almost identical to that of the shock absorber of the comparative example when the piston frequency is low, and thus maintains equivalent performance.

[0103] The dashed lines in Figures 8 and 9 show the simulation results of the damping force when the piston speed of the shock absorber 11 of the first embodiment alone is 0.6 m / s and a high frequency is input. The solid lines in Figures 8 and 9 show the simulation results of the damping force when the piston speed of the shock absorber of the comparative example alone is 0.6 m / s and a high frequency is input.

[0104] 8 and 9, in the shock absorber 11 of the first embodiment, when the piston frequency is high, the damping force on the extension side of the first damping valve 212 of the body valve 30 is almost unchanged compared to the shock absorber of the comparative example. This is because the first damping valve 212 of the body valve 30 has a lower differential pressure than the disc valve 58 on the extension side of the piston 45. Also, in the shock absorber 11 of the first embodiment, when the piston frequency is high, the second damping disc valve 222 of the body valve 30, which has a high contribution to the damping force on the compression side, has a slightly lower damping force after opening, as shown in the range surrounded by the dashed line X1 in FIG. 8 and the range surrounded by the dashed line X2 in FIG. 9, but the peak value remains the same as that of the shock absorber of the comparative example.

[0105] The dashed line in FIG. 10 shows the frequency characteristic of the damping force when the piston speed of the shock absorber 11 of the first embodiment is 0.3 m / s. The solid line in FIG. 10 shows the frequency characteristic of the damping force when the piston speed of the shock absorber of the comparative example is 0.3 m / s. From FIG. 10, it can be seen that, in the shock absorber 11 of the first embodiment having the pressure accumulation mechanism 251, the damping force on the compression side is slightly lowered when the piston frequency is high frequency, but the performance can be maintained almost the same as that of the shock absorber of the comparative example without the pressure accumulation mechanism. The shock absorber 11 of the first embodiment can improve quietness (sound and vibration) and harshness while firmly maintaining the basic performance of a conventional shock absorber without a pressure accumulation mechanism. The shock absorber 11 has the effect of improving the smoothness of the ride comfort by reducing the high frequency input of the piston frequency.

[0106] The above-mentioned Patent Documents 1 and 2 disclose shock absorbers having a body valve. However, there is a demand for suppressing the generation of abnormal noise in shock absorbers.

[0107] The shock absorber 11 of the first embodiment has a body valve 30 including a first passage 211 in which the flow of the oil L is generated by the movement of the piston 45 in one direction, a first damping valve 212 that provides resistance to the flow of the oil L from the reservoir chamber 18 on the upstream side of the first passage 211 to the second chamber 49 on the downstream side, a second passage 221 in which the flow of the oil L is generated by the movement of the piston 45 in the other direction, and a second damping disc valve 222 that provides resistance to the flow of the oil L from the second chamber 49 on the upstream side of the second passage 221 to the reservoir chamber 18 on the downstream side. The body valve 30 has a third passage 231 in which the second damping disc valve 222 always communicates between the reservoir chamber 18 on the upstream side and the second chamber 49 on the downstream side, and a fourth passage 241 that communicates with the reservoir chamber 18 on the upstream side. Therefore, the shock absorber 11 can introduce the oil L from the reservoir chamber 18 to the variable chamber 252 when the first damping valve 212 is opened during the extension stroke where the piston frequency is high and abnormal noise is noticeable. Therefore, the shock absorber 11 can suppress a sudden change in oil pressure when the first damping valve 212 is opened during the extension stroke where the piston frequency is high and abnormal noise is noticeable, and can reduce the rod acceleration, thereby suppressing the generation of abnormal noise. As a result, it is possible to achieve both the suppression of abnormal noise and the securing of damping force from an extremely low piston speed.

[0108] In the shock absorber 11 of the first embodiment, the body valve 30 communicates with the fourth passage 241, and a variable chamber 252 partitioned by a partition member 255 that moves in response to a pressure change in the upstream reservoir chamber 18 or the downstream second chamber 49 is disposed overlapping the second damping disc valve 222. In other words, a pressure accumulator mechanism 251 including the variable chamber 252 is disposed overlapping the second damping disc valve 222. This allows the shock absorber 11 to have a compact configuration.

[0109] In the shock absorber 11 of the first embodiment, the third passage 231 and the fourth passage 241 are formed in the valve disc 154 of the second damping disc valve 222, which is seated on the outer seat 88. Therefore, the shock absorber 11 can be further made compact in configuration.

[0110] In the shock absorber 11 of the first embodiment, the partition member 255 is composed of a conical spring 153 which enlarges the variable chamber 252 formed between the partition member 255 and the valve disc 154 during the extension stroke of the piston 45 and reduces the variable chamber 252 during the compression stroke, thereby making it possible to make the shock absorber 11 compact and suppressing costs from increasing.

[0111] In the shock absorber 11 of the first embodiment, the partition member 255 is provided with a relief mechanism 258 that relieves pressure in the variable chamber 252 after the pressure difference between the upstream variable chamber 252 and the downstream variable chamber 220 during the extension stroke of the piston 45 reaches a predetermined value, so that excessive deformation of the conical spring 153 can be suppressed and the durability of the conical spring 153 can be improved. In addition, the shock absorber 11 can increase the amount of oil L moving from the reservoir chamber 18 to the second chamber 49 by the relief mechanism 258 during the extension stroke, so that the insufficient flow rate due to the first damping valve 212 in the high piston speed range can be compensated for. Therefore, the shock absorber 11 can suppress excessive decompression of the second chamber 49 and suppress cavitation. In addition, the shock absorber 11 can achieve a further compact configuration because the partition member 255 is provided with the relief mechanism 258.

[0112] In the shock absorber 11 of the first embodiment, the second damping disc valve 222 is provided in the body valve 30, and therefore, abnormal noise caused by the operation of the body valve 30 can be effectively suppressed. In addition, even if the pressure accumulator mechanism 251 is provided in the body valve 30, the structure can be made compact, and therefore the stroke length of the piston rod 50 is not sacrificed.

[0113] The shock absorber 11 of the first embodiment has a pressure accumulation mechanism 251 between the valve base 25 having the outer seat 88 of the body valve 30 and the second damping disc valve 222 that opens and closes the outer seat 88, thereby further suppressing an increase in the axial length of the body valve 30.

[0114] [Second embodiment] Next, the second embodiment will be described with a focus on the differences from the first embodiment, mainly with reference to Fig. 11. Note that the same names and symbols are used for the parts common to the first embodiment.

[0115] As shown in FIG. 11, a shock absorber 11A of the second embodiment has a body valve 30A which is partially different from the body valve 30 instead of the body valve 30.

[0116] The body valve 30A has a pressure accumulation mechanism 251A that is partially different from the pressure accumulation mechanism 251 in place of the pressure accumulation mechanism 251. The pressure accumulation mechanism 251A has a partition member 255A that is partially different from the partition member 255 in place of the partition member 255. The partition member 255A has a conical spring 153A that is partially different from the conical spring 153 in place of the conical spring 153.

[0117] The conical spring 153A is also formed by press molding from a single flat plate material. The conical spring 153A has a base plate portion 161 and an outer peripheral tapered plate portion 162 similar to the conical spring 153, as well as an outermost peripheral plate portion 271. The outermost peripheral plate portion 271 spreads outward in the radial direction from the outer peripheral edge portion of the outer peripheral tapered plate portion 162. The outermost peripheral plate portion 271 is annular and is formed around the entire circumference of the outer peripheral tapered plate portion 162.

[0118] The disc spring 153A has a curved portion 272 between the outer peripheral tapered plate portion 162 and the outermost peripheral plate portion 271. The curved portion 272 is provided over the entire circumference of the disc spring 153A and has a circular shape.

[0119] When assembled in the body valve 30A, the conical spring 153A has an inner peripheral portion of the base plate portion 161 that is flat, and an outer peripheral portion of the base plate portion 161 that is tapered so as to move away from the valve disc 154 in the axial direction toward the radially outward direction. In this state, the conical spring 153A extends toward the valve disc 154 in a tapered shape such that the outer peripheral tapered plate portion 162 approaches the valve disc 154 in the axial direction toward the radially outward direction. In this state, the conical spring 153A has a curved portion 272 that abuts against the annular portion between the notch 171 and the passage hole 172 in the radial direction of the valve disc 154 over the entire circumference. In this state, the conical spring 153A extends in a tapered shape such that the outermost peripheral plate portion 271 moves away from the valve disc 154 in the axial direction toward the radially outward direction.

[0120] The body valve 30A has a second passage 221A that is partially different from the second passage 221 in place of the second passage 221. The second passage 221A has a variable chamber 220A that is partially different from the variable chamber 220 in place of the variable chamber 220. The variable chamber 220A is surrounded by the base main body portion 82, the inner sheet 84, the outer sheet 88, and the multiple protrusions 89 of the valve base 25, the disc 151, the partition member 255A, and the valve disc 154.

[0121] The hydraulic circuit diagram of the body valve 30A is similar to that of the body valve 30.

[0122] In the shock absorber 11A of the second embodiment, the body valve 30A operates in the same manner as the body valve 30.

[0123] The shock absorber 11A and its body valve 30A of the second embodiment have the same effects as those of the first embodiment. In addition, in the shock absorber 11A, the conical spring 153A of the body valve 30A thereof always abuts over the entire circumference on the annular portion between the notch 171 and the passage hole 172 in the radial direction of the valve disc 154 at the curved surface formed by bending the curved portion 272. In this way, since the conical spring 153A abuts on the valve disc 154 at the curved surface of the curved portion 272, it is possible to improve the sealing performance of the abutting portion with the valve disc 154 compared to the conical spring 153 that abuts on the valve disc 154 at the edge portion at the tip of the outer peripheral tapered plate portion 162.

[0124] [Third embodiment] Next, the third embodiment will be described with a focus on the differences from the first embodiment, mainly with reference to Figures 12 to 14. Note that the same names and symbols are used for the parts common to the first embodiment.

[0125] 12, a shock absorber 11B of the third embodiment has a body valve 30B that is partially different from the body valve 30 instead of the body valve 30. The body valve 30B has a pressure accumulation mechanism 251B that is partially different from the pressure accumulation mechanism 251 instead of the pressure accumulation mechanism 251. The pressure accumulation mechanism 251B has a partition member 255B that is different from the partition member 255 instead of the partition member 255. The pressure accumulation mechanism 251B has a disk 280 similar to the disk 151.

[0126] The partition member 255B is capable of fitting the shaft portion 103 of the pin member 101 inside. The partition member 255B has a substrate disk 281 and an outer peripheral disk 282. Both the substrate disk 281 and the peripheral disk 282 are made of metal. In the natural state before being assembled into the body valve 30B, the partitioning member 255B has a substrate disk 281 in the form of a circular flat plate with a certain thickness, as shown in Figs. 13 and 14. In the natural state before being assembled into the body valve 30B, the partitioning member 255B has an outer peripheral disk 282 in the form of a circular flat plate with a certain thickness. In the natural state before being assembled into the body valve 30B, the partitioning member 255B has an outer diameter of the outer peripheral disk 282 that is the same as the outer diameter of the substrate disk 281, and an inner diameter of the outer peripheral disk 282 that is larger than the inner diameter of the substrate disk 281. The outer peripheral disk 282 is coaxial with the substrate disk 281 and is fixed to one axial side of the substrate disk 281 by welding.

[0127] When assembling the body valve 30B, the disk 159, disk 158, the multiple valve disks 157, valve disk 156, valve disk 155, valve disk 154, disk 280, partition member 255B, disk 151, and valve base 25 are stacked on the head 102 in this order, while fitting the shaft portion 103 of the pin member 101 to the inside of each of them. At this time, the partition member 255B is oriented so that the outer peripheral disk 282 is located on the valve disk 154 side. Here, the thickness of the outer peripheral disk 282 is greater than the thickness of the disk 280.

[0128] The partitioning member 255B is clamped between the disks 151 and 280 by fastening the head 102 of the pin member 101 and the nut 201 at the inner circumferential side of the substrate disk 281. When the partitioning member 255B is assembled in the body valve 30B in this manner, the inner circumferential side of the substrate disk 281 of the partitioning member 255B becomes flat, and the outer circumferential side of the substrate disk 281 of the partitioning member 255B is deformed in a tapered shape so that the radially outward portion is separated from the valve disk 154 in the axial direction. In this state, the partitioning member 255B is tapered so that the outer circumferential disk 282 abuts against the valve disk 154 and the radially outward portion is separated from the valve disk 154 in the axial direction. At this time, the outer circumferential disk 282 abuts against the annular portion between the notch 171 and the passage hole 172 of the valve disk 154 over the entire circumference. Therefore, the partitioning member 255B is provided so as to cover the passage hole 172 of the valve disk 154.

[0129] The body valve 30B has a second passage 221B which is partially different from the second passage 221 in place of the second passage 221. The second passage 221B has a variable chamber 220B which is partially different from the variable chamber 220 in place of the variable chamber 220. The variable chamber 220B is surrounded by the base main body portion 82, the inner sheet 84, the outer sheet 88, and the multiple protrusions 89 of the valve base 25, the disc 151, the partition member 255B, and the valve disc 154.

[0130] In the body valve 30B, the base main body portion 82, the inner seat 84, the outer seat 88, and the multiple protrusions 89 of the valve base 25, the partition member 255B, the valve disc 154, and the discs 151 and 280 constitute a pressure accumulation mechanism 251B including a variable chamber 220B. In the pressure accumulation mechanism 251B, a portion surrounded by the partition member 255B, the disc 280, and the valve disc 154 constitutes a variable chamber 252B. The variable chamber 252B is partitioned from the variable chamber 220B of the second passage 221B by the partition member 255B. The variable chamber 252B communicates with the fourth passage 241. The partition member 255B seals between the variable chamber 252B and the variable chamber 220B when the outer peripheral disc 282 is in contact with the valve disc 154 over the entire circumference.

[0131] The partitioning member 255B moves in response to a pressure change in the upstream reservoir chamber 18 or the downstream second chamber 49 (see FIG. 2) when the piston 45 (see FIG. 1) moves in the extension direction. The partitioning member 255B moves in response to a pressure change in the upstream second chamber 49 (see FIG. 2) or the downstream reservoir chamber 18 when the piston 45 (see FIG. 1) moves in the contraction direction. The partitioning member 255B makes the variable chamber 252B larger and the variable chamber 220B smaller during the extension stroke of the piston 45 (see FIG. 1), while making the variable chamber 220B larger and the variable chamber 252B smaller during the contraction stroke of the piston 45 (see FIG. 1).

[0132] The variable chambers 220B, 252B are formed by the second damping disc valve 222B. The variable chambers 220B, 252B are arranged on the second damping disc valve 222B so as to overlap with the second damping disc valve 222B in the axial direction of the second damping disc valve 222B. The pressure accumulation mechanism 251B including the variable chambers 220B, 252B is arranged on the second damping disc valve 222B so as to overlap with the second damping disc valve 222B in the axial direction of the second damping disc valve 222B.

[0133] During the extension stroke when the piston speed is in the low speed range, the partitioning member 255B enlarges the variable chamber 252B with the outer circumferential disc 282 remaining in contact with the valve disc 154 over the entire circumference. Also, during the compression stroke, the partitioning member 255B enlarges the variable chamber 220B. Here, during the extension stroke when the piston speed is in the high speed range, the partitioning member 255B separates the outer circumferential disc 282 from the valve disc 154, connecting the variable chamber 252B to the variable chamber 220B. At that time, the partitioning member 255B abuts against the protruding portion 89 of the valve base 25 at the base disc 281, suppressing further deformation.

[0134] The shock absorber 11B and its body valve 30B of the third embodiment have substantially the same effects as those of the first embodiment.

[0135] [Fourth embodiment] Next, the fourth embodiment will be described with a focus on differences from the first embodiment, mainly with reference to Figures 15 to 18. Note that parts common to the first embodiment will be designated by the same names and reference numerals.

[0136] 15, in a shock absorber 11C of the fourth embodiment, a body valve 30C that is partially different from the body valve 30 is provided instead of the body valve 30. The body valve 30C has a valve base 25C that is partially different from the valve base 25 instead of the valve base 25.

[0137] The valve base 25C has a base portion 71C which is partially different from the base portion 71 in place of the base portion 71. The base portion 71C differs from the base portion 71 in that the protruding portion 89 is not provided.

[0138] The body valve 30C is provided with, on the axial leg portion 72 side of the base portion 71C, in order from the axial base portion 71C side, one disc 151 similar to the above, one valve disc 154 similar to the above, one valve disc 155 similar to the above, one disc 291, one partition member 255C, one disc 292, one valve disc 156C, multiple valve discs 157 similar to the above, specifically three valve discs 157, one disc 158 similar to the above, and one disc 159 similar to the above.

[0139] The valve disc 156C and the discs 291, 292 are all made of metal. The valve disc 156C and the discs 291, 292 are all in the form of a circular flat plate with a certain thickness and a hole, into which the shaft portion 103 of the pin member 101 can be fitted. The partition member 255C is in the form of an annular ring, into which the shaft portion 103 of the pin member 101 can be fitted.

[0140] The disks 291 and 292 are common parts having the same shape. The disks 291 and 292 have an outer diameter smaller than the passage hole 181 of the valve disk 155.

[0141] As shown in FIGS. 16 and 17, the partition member 255C has a substrate disk 301 and a pair of peripheral disks 302 and 303 having the same shape. The substrate disk 301 and the pair of peripheral disks 302, 303 are both made of metal.

[0142] In the partitioning member 255C, the substrate disk 301 is a circular flat plate with a certain thickness and a hole, into which the shaft portion 103 of the pin member 101 can be fitted, as shown in FIG. 15 . The substrate disk 301 is flexible. In addition, in the partitioning member 255C, a pair of outer peripheral disks 302, 303 are circular flat plates with a certain thickness and a hole. The pair of outer peripheral disks 302, 303 of the partitioning member 255C have the same outer diameter as the outer diameter of the substrate disk 301, and have an inner diameter larger than the inner diameter of the substrate disk 301.

[0143] As shown in Fig. 17, the outer peripheral disk 302 is coaxial with the substrate disk 301 and fixed to one side of the substrate disk 301 in the axial direction by welding. The outer peripheral disk 303 shown in Fig. 16 is coaxial with the substrate disk 301 and fixed to the other side of the substrate disk 301 opposite the outer peripheral disk 302 in the axial direction by welding. As shown in Fig. 15, the outer diameter of the partition member 255C, i.e., the outer diameters of the substrate disk 301 and the pair of outer peripheral disks 302 and 303, are equal to the outer diameters of the valve disks 154, 155 and 157. The thickness of the outer peripheral disk 302 is equal to the thickness of the disk 291, and the thickness of the outer peripheral disk 303 is equal to the thickness of the disk 292.

[0144] The valve disc 156C has an outer diameter equal to the outer diameters of the valve discs 154, 155, and 157. The valve disc 156C is flexible. A notch 191C is formed on the outer periphery of the valve disc 156C.

[0145] When assembling the body valve 30C, the pin member 101 is stacked on the head 102 in this order, with the shaft portion 103 of the pin member 101 fitted inside each of the disc 159, disc 158, multiple valve discs 157, valve disc 156C, disc 292, partition member 255C, disc 291, valve disc 155, valve disc 154, disc 151, and valve base 25C.

[0146] At least the inner circumferential side of each of disc 159, disc 158, multiple valve discs 157, valve disc 156C, disc 292, partition member 255C, disc 291, valve disc 155, valve disc 154 and disc 151 is clamped to head 102 of pin member 101 and inner sheet 84 of valve base 25C. The inner circumferential side of substrate disc 301 of partition member 255C is clamped to discs 291, 292.

[0147] The body valve 30C has a second passage 221C which is partially different from the second passage 221 in place of the second passage 221. The second passage 221C has a variable chamber 220C which is partially different from the variable chamber 220 in place of the variable chamber 220. The variable chamber 220C is formed by a portion surrounded by the base main body portion 82, the inner sheet 84, and the outer sheet 88 of the valve base 25C, the disc 151, and the valve disc 154, the passage holes 172, 181 of the valve discs 154, 155, and a portion surrounded by the partition member 255C, the valve disc 155, and the disc 291.

[0148] The body valve 30C is a second damping disc valve 222C that opens and closes a second passage 221C by the valve discs 154, 155, 156C, 157 and the partition member 255C moving away from and into contact with the outer seat 88. In the second passage 221C, a flow of oil L, which is a working fluid, is generated by the movement of the piston 45 (see FIG. 1) in the contraction direction. The second damping disc valve 222C applies resistance to the flow of oil L from the second chamber 49 (see FIG. 2) on the upstream side of the second passage 221C to the reservoir chamber 18 on the downstream side. The second damping disc valve 222C and a third passage 231, which is an orifice, are provided in the second passage 221C to constitute a second damping force generating mechanism 225C on the compression side that generates a damping force by suppressing the flow of oil L flowing in the second passage 221C.

[0149] In the body valve 30C, the inside of the notch 191C of the valve disc 156C serves as a fourth passage 241C (communication passage) that always communicates with the upstream reservoir chamber 18 when the piston 45 (see FIG. 1) moves in the extension direction. In other words, the second damping disc valve 222C has a fourth passage 241C. The fourth passage 241C is an orifice.

[0150] A part of the variable chamber 220C of the second passage 221C and the third passage 231 are formed in the valve disc 154 seated on the outer seat 88 of the second damping disc valve 222C.

[0151] In the body valve 30C, the base main body portion 82, the inner seat 84, and the outer seat 88 of the valve base 25C, the valve discs 154, 155, and 156C, the partition member 255C, and the discs 151, 291, and 292 constitute a pressure accumulating mechanism 251C including a variable chamber 220C.

[0152] In the pressure accumulation mechanism 251C, a portion surrounded by the valve disc 156C, the partition member 255C, and the disc 292 constitutes a variable chamber 252C. The variable chamber 252C is partitioned from the variable chamber 220C of the second passage 221C by the partition member 255C. The variable chamber 252C communicates with the fourth passage 241C.

[0153] The partitioning member 255C moves in response to a pressure change in the upstream reservoir chamber 18 or the downstream second chamber 49 (see FIG. 2) when the piston 45 (see FIG. 1) moves in the extension direction. The partitioning member 255C moves in response to a pressure change in the upstream second chamber 49 (see FIG. 2) or the downstream reservoir chamber 18 when the piston 45 (see FIG. 1) moves in the contraction direction. The partitioning member 255C makes the variable chamber 252C larger and the variable chamber 220C smaller during the extension stroke of the piston 45 (see FIG. 1), while making the variable chamber 220C larger and the variable chamber 252C smaller during the contraction stroke of the piston 45 (see FIG. 1).

[0154] When the partitioning member 255C deforms in a direction to enlarge the variable chamber 252C, if the partitioning member 255C deforms by a predetermined amount, the substrate disk 301 abuts against the valve disk 155, and further deformation is suppressed. When the partitioning member 255C deforms in a direction to enlarge the variable chamber 220C, if the partitioning member 255C deforms by a predetermined amount, the substrate disk 301 abuts against the valve disk 156C, and further deformation is suppressed. The partitioning member 255C has the outer peripheral disk 302 abutting against the valve disk 155 all around at all times.

[0155] The pressure accumulation mechanism 251C has a variable chamber 252C that communicates with the fourth passage 241C. The variable chamber 252C is partitioned from the second passage 221C by a partition member 255C that moves in response to a pressure change in the upstream reservoir chamber 18 or the downstream second chamber 49 (see FIG. 2) when the piston 45 (see FIG. 1) moves in the extension direction.

[0156] The variable chambers 220C, 252C are formed by the second damping disc valve 222C. The variable chamber 252C is disposed inside the second damping disc valve 222C. The variable chambers 220C, 252C are disposed on the second damping disc valve 222C so as to overlap with the second damping disc valve 222C in the axial direction of the second damping disc valve 222C. The pressure accumulation mechanism 251C including the variable chambers 220C, 252C is disposed on the second damping disc valve 222C so as to overlap with the second damping disc valve 222C in the axial direction of the second damping disc valve 222C.

[0157] The hydraulic circuit diagram of the body valve 30C described above is as shown in FIG. The body valve 30C is provided with an orifice 128, and a second damping force generating mechanism 225C on the compression side including a second damping disc valve 222C and a third passage 231 in a second passage 221C that communicates between the second chamber 49 and the reservoir chamber 18. The body valve 30C is also provided with a variable chamber 220C between the orifice 128 of the second passage 221C and the second damping force generating mechanism 225C. The body valve 30C is also provided with a variable chamber 252C of the pressure accumulation mechanism 251C that communicates with the reservoir chamber 18 via a fourth passage 241C that is an orifice. The body valve 30C is not provided with a relief mechanism.

[0158] Next, the main operation of the body valve 30C will be described.

[0159] During the extension stroke, the pressure in the second chamber 49 (see FIG. 2) becomes lower than the pressure in the reservoir chamber 18 shown in FIG. 15, and the oil L in the reservoir chamber 18 is introduced into the first passage 211 and flows into the second chamber 49 (see FIG. 2) through the first damping force generating mechanism 215 (see FIG. 2). In addition, the oil L in the reservoir chamber 18 is introduced into the variable chamber 252C of the pressure accumulating mechanism 251C from the fourth passage 241C, deforming the partition member 255C and expanding the variable chamber 252C. At that time, the oil L in the contracted variable chamber 220C is discharged into the second chamber 49 (see FIG. 2) through the second passage 221C.

[0160] In the extension stroke at the time of low frequency when the piston frequency is lower than a predetermined value, the stroke of the piston 45 (see FIG. 1) is large, so that in the early stage when the oil L is introduced from the reservoir chamber 18 to the variable chamber 252C through the fourth passage 241C, the partition member 255C is largely deflected, and the substrate disk 301 abuts against the valve disk 155, suppressing further deformation. As a result, the variable chamber 252C is in a state where the increase in volume is suppressed, and the variable chamber 252C cannot absorb the increase in the amount of oil L introduced. Then, the force of the oil L in the reservoir chamber 18 pushing the first damping valve 212 (see FIG. 2) in the opening direction increases. Therefore, the first damping valve 212 (see FIG. 2) opens, and the oil L flows into the second chamber 49 (see FIG. 2) through the first passage 211. Therefore, in the extension stroke at the time of low frequency when the piston frequency is lower than a predetermined value, the damping force characteristic is the same as that in the case where the pressure accumulation mechanism 251C is not present.

[0161] On the other hand, in the extension stroke when the piston frequency is a high frequency equal to or higher than a predetermined value, the stroke of the piston 45 (see FIG. 1) is small, and therefore the volume of the oil L introduced from the reservoir chamber 18 to the variable chamber 252C through the fourth passage 241C is small. Therefore, the partition member 255C has a small amount of deflection and does not abut against the valve disc 155, or is deformable even if it abuts against it. Therefore, most of the increase in the oil L introduced from the reservoir chamber 18 to the variable chamber 252C through the fourth passage 241C is absorbed by the deflection of the partition member 255C. Then, the force with which the oil L in the reservoir chamber 18 pushes the first damping valve 212 (see FIG. 2) in the opening direction is suppressed compared to when the piston frequency is a low frequency lower than a predetermined value, and the damping force is lower and softer than at low frequencies.

[0162] During the compression stroke, the pressure in the second chamber 49 (see FIG. 2) becomes higher than the pressure in the reservoir chamber 18, and the oil L in the second chamber 49 (see FIG. 2) is introduced into the second passage 221C and flows into the reservoir chamber 18 via the second damping force generating mechanism 225C. In addition, the oil L in the second chamber 49 (see FIG. 2) is introduced into the variable chamber 220C of the pressure accumulating mechanism 251C, deforming the partition member 255C and expanding the variable chamber 220C. At that time, the oil L in the contracting variable chamber 252C is discharged into the reservoir chamber 18 via the fourth passage 241C.

[0163] In the compression stroke when the piston frequency is lower than a predetermined value, the stroke of the piston 45 (see FIG. 1) is large, so that in the early stage of the introduction of the oil L from the second chamber 49 (see FIG. 2) into the variable chamber 220C, the partition member 255C is largely deflected and abuts against the valve disc 156C, suppressing further deformation. As a result, the volume of the variable chamber 220C is in a state of not changing, and the variable chamber 220C cannot absorb the increase in the amount of oil L introduced. Then, the pressure in the variable chamber 220C rises to a high pressure, and the force pushing the second damping disc valve 222C in the opening direction increases. Therefore, the second damping disc valve 222C opens, and the oil L flows into the reservoir chamber 18 through the gap with the outer seat 88. Therefore, in the compression stroke when the piston frequency is low and lower than a predetermined value, the damping force characteristics are the same as when there is no pressure accumulation mechanism 251C.

[0164] On the other hand, in the compression stroke when the piston frequency is equal to or higher than a predetermined value, the stroke of the piston 45 (see FIG. 1) is small, and therefore the volume of the oil L introduced from the second chamber 49 (see FIG. 2) into the variable chamber 220C is small, and the partitioning member 255C is easily deformed with a small amount of deflection. Therefore, most of the increase in the oil L introduced from the second chamber 49 (see FIG. 2) into the variable chamber 220C is absorbed by the deflection of the partitioning member 255C. Therefore, the variable chamber 220C is at a low pressure, and the opening pressure of the second damping disc valve 222C does not increase. Therefore, in the compression stroke, when the piston frequency is high, the damping force is lower and softer than when the piston frequency is low.

[0165] The shock absorber 11C and its body valve 30C of the fourth embodiment have substantially the same effects as those of the first embodiment.

[0166] Incidentally, shock absorber 11C of the fourth embodiment does not have a relief mechanism. However, partition member 255C, which deforms due to the pressure difference between variable chambers 220C, 252C, is sandwiched between valve disc 155 and valve disc 156C, and even at high speeds, deformation is limited by valve disc 155 or valve disc 156, thereby suppressing excessive stress increase.

[0167] [Fifth embodiment] Next, the fifth embodiment will be described with a focus on differences from the fourth embodiment, mainly with reference to Figures 19 and 20. Note that parts common to the fourth embodiment will be designated by the same names and symbols.

[0168] 19, a shock absorber 11D of the fifth embodiment has a body valve 30D which is partially different from the body valve 30C instead of the body valve 30C. The body valve 30D has a partition member 255D instead of the partition member 255C.

[0169] The partition member 255D has a partition member main body 153D and an opening / closing disk 152D. The partition member main body 153D and the opening / closing disk 152D are both capable of fitting the shaft portion 103 of the pin member 101 inside.

[0170] The partition member main body 153D has a substrate disk 301D and a pair of peripheral disks 302D and 303D having the same shape. The substrate disk 301D and the pair of peripheral disks 302D, 303D are all made of metal. In the natural state before being assembled into the body valve 30D, the partition member main body 153D has a substrate disk 301D in the shape of a circular plate with a certain thickness. The substrate disk 301D is flexible. A passage hole 163D penetrating the substrate disk 301D in the axial direction is formed in the substrate disk 301D at a radially intermediate position. The substrate disk 301D has a plurality of passage holes 163D, specifically 13 passage holes 163D, formed at equal intervals in the circumferential direction, as shown in FIG.

[0171] 19, the partitioning member main body 153D is a pair of peripheral disks 302D, 303D each having a certain thickness and formed in a circular flat plate shape with a hole. The partitioning member main body 153D has a pair of peripheral disks 302D, 303D whose outer diameter is the same as that of the substrate disk 301D. The pair of peripheral disks 302D, 303D have an inner diameter larger than that of the substrate disk 301D.

[0172] As shown in Fig. 20, the outer peripheral disk 302D is coaxial with the substrate disk 301D and fixed by welding to one side of the substrate disk 301D in the axial direction. The outer peripheral disk 303D shown in Fig. 19 is coaxial with the substrate disk 301D and fixed by welding to the other side of the substrate disk 301D opposite the outer peripheral disk 302D in the axial direction. The outer diameter of the partition member main body 153D, i.e., the outer diameter of the substrate disk 301D and the pair of identically shaped outer peripheral disks 302D, 303D, is equal to the outer diameter of the valve disks 154, 155, 156C, 157. The substrate disk 301D has a plurality of passage holes 163D formed radially inward of the pair of outer peripheral disks 302D, 303D.

[0173] The opening / closing disk 152D is a circular flat plate with a certain thickness in a natural state before being assembled into the body valve 30D. The opening / closing disk 152D is flexible. The opening / closing disk 152D is capable of closing a plurality of passage holes 163D by being in surface contact with the substrate disk 301D of the partition member main body 153D.

[0174] The body valve 30D has a disk 291D having a thickness different from that of the disk 291, and a disk 292D having a thickness different from that of the disk 292. The disks 291D and 292D have the same outer diameter. The thickness of the outer peripheral disk 302D is thinner than that of the disk 291D. The thickness of the outer peripheral disk 303D is thicker than that of the disk 292D.

[0175] When assembling the body valve 30D, the pin member 101 is stacked on the head 102 in this order, with the shaft portion 103 of the pin member 101 fitted inside each of the disc 159, disc 158, multiple (specifically, two) valve discs 157, valve disc 156C, disc 292D, partition member main body 153D, opening / closing disc 152D, disc 291D, valve disc 155, valve disc 154, disc 151 and valve base 25C.

[0176] At least the inner circumferential side of each of disc 159, disc 158, the multiple valve discs 157, valve disc 156C, disc 292C, partition member main body 153D, open / close disc 152D, disc 291D, valve disc 155, valve disc 154 and disc 151 is clamped to head 102 of pin member 101 and inner sheet 84 of valve base 25D. The inner circumferential side of substrate disc 301D of partition member main body 153D is clamped to discs 291D and 292D.

[0177] When assembled into the body valve 30D, the substrate disk 301D of the partition member main body 153D has both its inner and outer peripheral portions flat, and the intermediate portion between them is deformed in a tapered shape so that it approaches the valve disk 155 in the axial direction as it moves radially outward.

[0178] When assembled into the body valve 30D, the opening / closing disc 152D has an inner peripheral portion that is flat, and an outer peripheral portion that is tapered in accordance with the substrate disc 301D so that the radially outward portion approaches the valve disc 155 in the axial direction. Therefore, the opening / closing disc 152D comes into surface contact with the substrate disc 301D by its elastic force, and closes the multiple passage holes 163D.

[0179] The body valve 30D has a second passage 221D which is partially different from the second passage 221C in place of the second passage 221C. The second passage 221D has a variable chamber 220D which is partially different from the variable chamber 220C in place of the variable chamber 220C. The variable chamber 220D is formed by a portion surrounded by the base main body portion 82, the inner sheet 84, and the outer sheet 88 of the valve base 25C, the disc 151, and the valve disc 154, the passage holes 172, 181 of the valve discs 154, 155, and a portion surrounded by the partition member 255D, the valve disc 155, and the disc 291D.

[0180] The body valve 30D is a second damping disc valve 222D that opens and closes a second passage 221D by the valve discs 154, 155, 156C, 157 and the partition member 255D moving away from and into contact with the outer seat 88. In the second passage 221D, a flow of oil L, which is a working fluid, is generated by the movement of the piston 45 (see FIG. 1) in the contraction direction. The second damping disc valve 222D applies resistance to the flow of oil L from the second chamber 49 (see FIG. 1) on the upstream side of the second passage 221D to the reservoir chamber 18 on the downstream side. The second damping disc valve 222D and a third passage 231, which is an orifice, are provided in the second passage 221D to constitute a second damping force generating mechanism 225D on the compression side that generates a damping force by suppressing the flow of oil L flowing in the second passage 221D.

[0181] A part of the variable chamber 220D of the second passage 221D and the third passage 231 are formed in the valve disc 154 seated on the outer seat 88 of the second damping disc valve 222D.

[0182] In the body valve 30D, the base main body portion 82, inner seat 84, and outer seat 88 of the valve base 25C, valve discs 154, 155, and 156C, a partition member 255D, and discs 151, 291D, and 292D constitute a pressure accumulating mechanism 251D including a variable chamber 220D.

[0183] In the pressure accumulation mechanism 251D, a portion surrounded by the valve disc 156C, the partition member 255D, and the disc 292D constitutes a variable chamber 252D. The variable chamber 252D is partitioned from the variable chamber 220D of the second passage 221D by the partition member 255D. The variable chamber 252D communicates with the fourth passage 241C.

[0184] The partitioning member 255D moves in response to a pressure change in the upstream reservoir chamber 18 or the downstream second chamber 49 (see FIG. 2) when the piston 45 (see FIG. 1) moves in the extension direction. The partitioning member 255D moves in response to a pressure change in the upstream second chamber 49 (see FIG. 2) or the downstream reservoir chamber 18 when the piston 45 (see FIG. 1) moves in the contraction direction. The partitioning member 255D makes the variable chamber 252D larger and the variable chamber 220D smaller during the extension stroke of the piston 45 (see FIG. 1), while making the variable chamber 220D larger and the variable chamber 252D smaller during the contraction stroke of the piston 45 (see FIG. 1).

[0185] When the partitioning member 255D deforms in a direction to enlarge the variable chamber 220D, when the partitioning member 255D deforms by a predetermined amount, the substrate disk 301D of the partitioning member main body 153D abuts against the valve disk 156C, suppressing further deformation. The partitioning member 255D has the outer peripheral disk 302D in constant abutment against the valve disk 155C over the entire circumference.

[0186] The pressure accumulation mechanism 251D has a variable chamber 252D that communicates with the fourth passage 241C. The variable chamber 252D is partitioned from the variable chamber 220D of the second passage 221D by a partition member 255D that moves in response to a pressure change in the upstream reservoir chamber 18 or the downstream second chamber 49 (see FIG. 2) when the piston 45 (see FIG. 1) moves in the extension direction.

[0187] The variable chambers 220D, 252D are formed by the second damping disc valve 222D. The variable chamber 252D is disposed inside the second damping disc valve 222D. The variable chambers 220D, 252D are disposed on the second damping disc valve 222D so as to overlap with the second damping disc valve 222D in the axial direction. The pressure accumulation mechanism 251D including the variable chambers 220D, 252D is disposed on the second damping disc valve 222D so as to overlap with the second damping disc valve 222D in the axial direction.

[0188] The passage hole 163D of the partition member main body 153D and the opening / closing disc 152D constitute a relief mechanism 258D that relieves the variable chamber 252D after the differential pressure between the upstream variable chamber 252D and the downstream variable chamber 220D reaches a predetermined value when the piston 45 (see Figure 1) moves in the extension direction.

[0189] The hydraulic circuit diagram of the body valve 30D is similar to that of the body valve 30.

[0190] Next, the main operation of the body valve 30D will be described.

[0191] During the extension stroke, the pressure in the second chamber 49 (see FIG. 2) becomes lower than the pressure in the reservoir chamber 18, and the oil L in the reservoir chamber 18 is introduced into the first passage 211 and flows into the second chamber 49 (see FIG. 2) via the first damping force generating mechanism 215 (see FIG. 2). In addition, the oil L in the reservoir chamber 18 is introduced into the variable chamber 252D of the pressure accumulating mechanism 251D from the fourth passage 241C, deforming the partition member 255D and expanding the variable chamber 252D. At that time, the oil L in the contracted variable chamber 220D is discharged into the second chamber 49 (see FIG. 2) via the second passage 221D.

[0192] During the extension stroke when the piston speed is low and the piston frequency is low, the stroke of the piston 45 (see FIG. 1) is large, so that the partition member 255D is largely deflected at the beginning of the introduction of the oil L from the reservoir chamber 18 to the variable chamber 252D through the fourth passage 241C, and further deformation is suppressed. As a result, the variable chamber 252D is in a state where the increase in volume is suppressed, and the variable chamber 252D cannot absorb the increase in the amount of oil L introduced. Then, the force of the oil L in the reservoir chamber 18 pushing the first damping valve 212 (see FIG. 2) in the opening direction increases. Therefore, the first damping valve 212 (see FIG. 2) opens, and the oil L flows into the second chamber 49 (see FIG. 2) through the first passage 211. Therefore, during an extension stroke when the piston speed is low and the piston frequency is low, the damping force characteristics are the same as in the case where there is no pressure accumulation mechanism 251D.

[0193] On the other hand, even when the piston speed is low and the piston frequency is high and equal to or higher than a predetermined value, the stroke of the piston 45 (see FIG. 1) is small during the extension stroke, and therefore the volume of the oil L introduced from the reservoir chamber 18 through the fourth passage 241C into the variable chamber 252D is small. For this reason, the partitioning member 255D also has a small amount of deflection. For this reason, most of the increase in the oil L introduced from the reservoir chamber 18 through the fourth passage 241C into the variable chamber 252D is absorbed by the deflection of the partitioning member 255D. Then, the force with which the oil L in the reservoir chamber 18 pushes the first damping valve 212 (see FIG. 2) in the opening direction is suppressed more than when the piston frequency is low and lower than a predetermined value, and the damping force is lower and softer than when the frequency is low.

[0194] In addition, during the extension stroke when the piston speed is high and equal to or greater than a predetermined value, the opening / closing disc 152D deforms and separates from the partition member main body 153D. In other words, the relief mechanism 258D opens. This allows the oil L in the variable chamber 252D to flow into the second chamber 49 (see FIG. 2) through the second passage 221D including the variable chamber 220D.

[0195] During the compression stroke, the pressure in the second chamber 49 (see FIG. 2) becomes higher than the pressure in the reservoir chamber 18, and the oil L in the second chamber 49 (see FIG. 2) is introduced into the second passage 221D and flows into the reservoir chamber 18 via the second damping force generating mechanism 225D. In addition, the oil L in the second chamber 49 (see FIG. 2) is introduced into the variable chamber 220D of the pressure accumulating mechanism 251D, deforming the partition member 255D and expanding the variable chamber 220D. At that time, the oil L in the contracting variable chamber 252D is discharged into the reservoir chamber 18 via the fourth passage 241C.

[0196] In the compression stroke when the piston frequency is lower than a predetermined value, the stroke of the piston 45 (see FIG. 1) is large, so that in the early stage of the introduction of the oil L from the second chamber 49 (see FIG. 2) into the variable chamber 220D, the partition member 255D is largely deflected and abuts against the valve disc 156C, suppressing further deformation. As a result, the volume of the variable chamber 220D is in a state of not changing, and the variable chamber 220D cannot absorb the increase in the amount of oil L introduced. Then, the pressure in the variable chamber 220D rises to a high pressure, and the force pushing the second damping disc valve 222D in the opening direction becomes strong. Therefore, the second damping disc valve 222D opens, and the oil L flows into the reservoir chamber 18 through the gap with the outer seat 88. Therefore, in the compression stroke when the piston frequency is low and lower than a predetermined value, the damping force characteristic is the same as that in the case where there is no pressure accumulation mechanism 251D.

[0197] On the other hand, in the compression stroke when the piston frequency is equal to or higher than a predetermined value, the stroke of the piston 45 (see FIG. 1) is small, and therefore the volume of the oil L introduced from the second chamber 49 (see FIG. 2) into the variable chamber 220D is small, and the partition member 255D is easily deformed with a small amount of deflection. Therefore, most of the increase in the oil L introduced from the second chamber 49 (see FIG. 2) into the variable chamber 220D is absorbed by the deflection of the partition member 255D. Therefore, the variable chamber 220D is at a low pressure, and the opening pressure of the second damping disc valve 222D does not increase. Therefore, in the compression stroke, when the piston frequency is high, the damping force is lower and softer than when the piston frequency is low.

[0198] The shock absorber 11D and its body valve 30D of the fifth embodiment have the same effects as those of the first embodiment.

[0199] [Sixth embodiment] Next, the sixth embodiment will be described with a focus on the differences from the first embodiment, mainly based on Fig. 21. Note that the same names and symbols are used for the parts common to the first embodiment.

[0200] As shown in FIG. 21, a shock absorber 11E of the sixth embodiment has a body valve 30E which is partially different from the body valve 30 instead of the body valve 30.

[0201] The body valve 30E is provided with, on the axial leg portion 72 side of the base portion 71, in the following order from the axial base portion 71 side: one disc 311, one disc 312, one opening / closing disc 152E, one partition disc 314, one disc 315, one belleville spring 153E, one valve disc 154E, one valve disc 155 similar to the above, one valve disc 156 similar to the above, multiple valve discs 157 similar to the above, specifically three valve discs 157 similar to the above, one disc 158 similar to the above, and one disc 159 similar to the above.

[0202] Valve disc 154E differs from valve disc 154 in that it has a passage hole 172E which is smaller than passage hole 172 and is positioned in a different position than passage hole 172.

[0203] The disks 311, 312, 315, the opening / closing disk 152E, the partition disk 314, and the conical spring 153E are all made of metal. The disks 311, 312, 315 are all circular flat plates with holes of a certain thickness, into which the shaft portion 103 of the pin member 101 can be fitted. The opening / closing disk 152E, the conical spring 153E, and the partition disk 314 are all annular in shape, into which the shaft portion 103 of the pin member 101 can be fitted.

[0204] The disk 311 has an outer diameter larger than the outer diameter of the inner seat 84 of the valve base 25 so as not to come into contact with the plurality of protrusions 89 . The disk 312 has an outer diameter equal to the outer diameter of the inner seat 84 of the valve base 25 and smaller than the outer diameter of the disk 311 .

[0205] The opening / closing disc 152E is a circular flat plate with a certain thickness in its natural state before being assembled into the body valve 30E. The opening / closing disc 152E is flexible. The opening / closing disc 152E has an outer diameter larger than the outer diameter of the disc 311 and has an outer diameter that does not contact the multiple protrusions 89 of the valve base 25.

[0206] The partition disc 314 is a circular flat plate with a certain thickness in its natural state before being assembled into the body valve 30E. The partition disc 314 has an outer diameter larger than the outer diameter of the opening / closing disc 152E and can abut against the multiple protrusions 89. The partition disc 314 is flexible. The partition disc 314 has multiple passage holes 321 formed at equal intervals in the circumferential direction of the partition disc 314 at positions that are opened and closed by the opening / closing disc 152E. Disk 315 has an outer diameter equal to the outer diameter of disk 312 .

[0207] The conical spring 153E is formed by pressing a single flat plate material. The conical spring 153E has a base portion 161E and an outer peripheral tapered plate portion 162E. The conical spring 153E is flexible.

[0208] The substrate portion 161E is a circular flat plate with a certain thickness. The substrate portion 161E is formed with a passage hole 163E penetrating the substrate portion 161E in the axial direction of the substrate portion 161E. The substrate portion 161E is formed with a plurality of passage holes 163E at equal intervals in the circumferential direction of the substrate portion 161E.

[0209] The outer peripheral tapered plate portion 162E expands in a tapered shape from the outer peripheral edge portion of the substrate portion 161E. The outer peripheral tapered plate portion 162E has a larger diameter as it moves away from the substrate portion 161E in the axial direction of the substrate portion 161E. The outer peripheral tapered plate portion 162E is annular and is formed around the entire circumference of the substrate portion 161E.

[0210] When assembling the body valve 30E, the pin member 101 is stacked on the head 102 in the order of disc 159, disc 158, multiple valve discs 157, valve disc 156, valve disc 155, valve disc 154E, conical spring 153E, disc 315, partition disc 314, opening / closing disc 152E, disc 312, disc 311, and valve base 25, with the shaft portion 103 of the pin member 101 fitted inside each of them.

[0211] At this time, the conical spring 153E is oriented so that the outer peripheral tapered plate portion 162E extends axially away from the valve disc 154E. Also, at this time, the valve base 25 is oriented so that the inner seat 84 abuts against the disc 311.

[0212] When assembled into the body valve 30E, the disc 159, disc 158, the multiple valve discs 157, valve disc 156, valve disc 155, valve disc 154E, disc spring 153E, disc 315, partition disc 314, open / close disc 152E, disc 312, and disc 311 are clamped at least on their inner circumferential sides to the head 102 of the pin member 101 and the inner seat 84 of the valve base 25. At that time, the disc spring 153E has the inner circumferential side of the base plate portion 161E clamped to the disc 315 and the valve disc 154E.

[0213] When assembled into the body valve 30E, the base plate portion 161E of the conical spring 153E is in surface contact with the valve disc 154E, and the passage hole 163E communicates with the passage hole 172E.

[0214] When assembled into the body valve 30E, the partition disc 314 has an inner portion that is flat and an outer portion that abuts against the outer peripheral edge of the outer peripheral tapered plate portion 162E of the conical spring 153E, and deforms into a tapered shape such that the radially outward portion moves away from the valve disc 154E in the axial direction.

[0215] When assembled into the body valve 30E, the opening / closing disc 152E has an inner peripheral portion that is flat, and an outer peripheral portion that is deformed following the shape of the partition disc 314 and comes into surface contact with the partition disc 314 by its elastic force. At that time, the opening / closing disc 152E entirely covers the multiple passage holes 321 of the partition disc 314, closing the multiple passage holes 321.

[0216] The body valve 30E has a second passage 221E, which is partially different from the second passage 221, instead of the second passage 221. The second passage 221E includes a variable chamber 220E surrounded by the base body portion 82, the inner seat 84, the outer seat 88, and the multiple protrusions 89 of the valve base 25, the discs 311 and 312, the opening / closing disc 152E, the partition disc 314, the conical spring 153E, and the valve disc 154E. The second passage 221E includes a third passage 231, which is an orifice in the notch 171 of the valve disc 154E. The third passage 231 constantly communicates the variable chamber 220E with the reservoir chamber 18.

[0217] The body valve 30E is a second damping disc valve 222E that opens and closes a second passage 221E by the valve discs 154E, 155-157 moving away from and into contact with the outer seat 88. In the second passage 221E, a flow of oil L, which is a working fluid, is generated by the movement of the piston 45 (see FIG. 1) in the contraction direction. The second damping disc valve 222E applies resistance to the flow of oil L from the second chamber 49 (see FIG. 2) on the upstream side of the second passage 221E to the reservoir chamber 18 on the downstream side.

[0218] A second damping disc valve 222E and a third passage 231 which is an orifice are provided in the second passage 221E to constitute a second damping force generating mechanism 225E on the compression side which generates a damping force by suppressing the flow of oil liquid L flowing through the second passage 221E.

[0219] In the body valve 30E, the notch 191 and the passage hole 192 of the valve disc 156 of the second damping disc valve 222E, the passage hole 181 of the valve disc 155, and the passage hole 172E of the valve disc 154E form a fourth passage 241E (communicating passage) that is constantly connected to the upstream reservoir chamber 18 when the piston 45 (see Figure 1) moves in the extension direction.

[0220] In the fourth passage 241E, the inside of the notch 191 of the valve disc 156 forms an orifice 242. In the fourth passage 241E, the inside of the passage hole 192 of the valve disc 156, the inside of the passage hole 181 of the valve disc 155, and the inside of the passage hole 172E of the valve disc 154E form an intermediate chamber 243E.

[0221] The third passage 231 and a portion of the fourth passage 241E are formed in a valve disc 154E that is seated on the outer seat 88 of the second damping disc valve 222E.

[0222] The body valve 30E includes the base main body portion 82, inner seat 84, outer seat 88 and multiple protrusions 89 of the valve base 25, discs 311, 312, 315, an opening / closing disc 152E, a partition disc 314, a conical spring 153E and a valve disc 154E, which together form a pressure accumulation mechanism 251E including a variable chamber 220E.

[0223] In the pressure accumulation mechanism 251E, a portion surrounded by the opening / closing disc 152E, the partition disc 314, the conical spring 153E, and the disc 315 constitutes a variable chamber 252E. The variable chamber 252E is partitioned from the variable chamber 220E of the second passage 221E by the conical spring 153E, the partition disc 314, and the opening / closing disc 152E. The conical spring 153E, the partition disc 314, and the opening / closing disc 152E constitute a partition member 255E that partitions the variable chamber 252E and the variable chamber 220E. The variable chamber 252E communicates with the fourth passage 241E.

[0224] The partitioning member 255E moves in response to a pressure change in the upstream reservoir chamber 18 or the downstream second chamber 49 (see FIG. 2) when the piston 45 (see FIG. 1) moves in the extension direction. The partitioning member 255E moves in response to a pressure change in the upstream second chamber 49 (see FIG. 2) or the downstream reservoir chamber 18 when the piston 45 (see FIG. 1) moves in the contraction direction. The partitioning member 255E is composed of a Belleville spring 153E. The partitioning member 255E makes the variable chamber 252E larger and the variable chamber 220E smaller during the extension stroke of the piston 45 (see FIG. 1), while making the variable chamber 220E larger and the variable chamber 252E smaller during the contraction stroke of the piston 45 (see FIG. 1).

[0225] When the partition member 255E deforms in a direction to enlarge the variable chamber 252E, if the partition member 255E deforms a predetermined amount, the partition disk 314 abuts against the protrusion 89 of the valve base 25, and further deformation is suppressed. At that time, the outer peripheral tapered plate portion 162E of the conical spring 153E abuts against the partition disk 314 over the entire circumference, thereby sealing between the variable chamber 252E and the variable chamber 220E. When the partition member 255E deforms in a direction to enlarge the variable chamber 220E, if the partition member 255E deforms a predetermined amount, the valve disk 154E suppresses further deformation. At that time, the outer peripheral tapered plate portion 162E of the conical spring 153E abuts against the valve disk 154E over the entire circumference, thereby sealing between the variable chamber 252E and the variable chamber 220E.

[0226] When the pressure difference between the upstream variable chamber 252E and the downstream variable chamber 220E reaches a predetermined value during movement of the piston 45 (see FIG. 1) in the extension direction, the opening / closing disc 152E separates from the partition disc 314, opening the passage hole 321 of the partition disc 314 and connecting the variable chamber 252E to the variable chamber 220E. The passage hole 321 of the partition disc 314 and the opening / closing disc 152E constitute a relief mechanism 258E that relieves the inside of the variable chamber 252E after the pressure difference between the upstream variable chamber 252E and the downstream variable chamber 220E during movement of the piston 45 (see FIG. 1) in the extension direction reaches a predetermined value.

[0227] When the pressure difference between the upstream variable chamber 252E and the downstream variable chamber 220E reaches a predetermined value during the movement of the piston 45 (see FIG. 1) in the extension direction, the outer peripheral tapered plate portion 162E of the conical spring 153E separates from the open / close disc 152E to connect the variable chamber 252E to the variable chamber 220E. The outer peripheral tapered plate portion 162E of the conical spring 153E and the partition disc 314 constitute a relief mechanism 331 that relieves the inside of the variable chamber 252E after the pressure difference between the upstream variable chamber 252E and the downstream variable chamber 220E during the movement of the piston 45 (see FIG. 1) in the extension direction reaches a predetermined value. In other words, the partition member 255E is provided with the relief mechanisms 258E, 331.

[0228] The pressure accumulation mechanism 251E has a variable chamber 252E that communicates with the fourth passage 241E. The variable chamber 252E is partitioned from the variable chamber 220E of the second passage 221E by a partition member 255E that moves in response to a pressure change in the upstream reservoir chamber 18 or the downstream second chamber 49 (see FIG. 2) when the piston 45 (see FIG. 1) moves in the extension direction.

[0229] The variable chambers 220E, 252E are disposed on the second damping disc valve 222E so as to overlap in the axial direction of the second damping disc valve 222E. The pressure accumulation mechanism 251E including the variable chambers 220E, 252E is disposed on the second damping disc valve 222E so as to overlap in the axial direction of the second damping disc valve 222E.

[0230] The hydraulic circuit diagram of the body valve 30E described above is the same as that of the body valve 30.

[0231] Next, the main operation of the body valve 30E will be described.

[0232] During the extension stroke, the pressure in the second chamber 49 (see FIG. 2) becomes lower than the pressure in the reservoir chamber 18, and the oil L in the reservoir chamber 18 is introduced into the first passage 211 and flows into the second chamber 49 (see FIG. 2) via the first damping force generating mechanism 215 (see FIG. 2). In addition, the oil L in the reservoir chamber 18 is introduced into the variable chamber 252E of the pressure accumulating mechanism 251E from the fourth passage 241E, deforming the partition member 255E and expanding the variable chamber 252E. At that time, the oil L in the contracted variable chamber 220E is discharged into the second chamber 49 (see FIG. 2) via the second passage 221E.

[0233] During the extension stroke when the piston speed is low and the piston frequency is low, the stroke of the piston 45 (see FIG. 1) is large, so that in the early stage of the introduction of the oil L from the reservoir chamber 18 to the variable chamber 252E through the fourth passage 241E, the partition member 255E is largely deflected, and the partition disk 314 abuts against the protruding portion 89 of the valve base 25, suppressing further deformation. At that time, the conical spring 153E maintains the abutment state with the outer peripheral tapered plate portion 162E. As a result, the variable chamber 252E is in a state in which the increase in volume is suppressed, and the variable chamber 252E cannot absorb the increase in the amount of oil L introduced. Then, the force of the oil L in the reservoir chamber 18 pushing the first damping valve 212 in the opening direction becomes strong. Therefore, the first damping valve 212 opens, and the oil L flows into the second chamber 49 (see FIG. 2) through the first passage 211. Therefore, during an extension stroke when the piston speed is low and the piston frequency is low, the damping force characteristics are the same as in the case where there is no pressure accumulation mechanism 251E.

[0234] On the other hand, even when the piston speed is low and the piston frequency is high and equal to or higher than the predetermined value, the stroke of the piston 45 (see FIG. 1) is small, so that the volume of the oil L introduced from the reservoir chamber 18 to the variable chamber 252E through the fourth passage 241E is small. Therefore, the partition disk 314 has a small amount of deflection and does not abut against the protruding portion 89 of the valve base 25, or is deformable even if it abuts against it. Even in this case, the conical spring 153E maintains the abutment state with the outer peripheral tapered plate portion 162E. Therefore, most of the increase in the oil L introduced from the reservoir chamber 18 to the variable chamber 252E through the fourth passage 241E is absorbed by the deflection of the partition disk 314. Then, the force of the oil L in the reservoir chamber 18 pushing the first damping valve 212 in the opening direction is suppressed compared to when the piston frequency is low and lower than the predetermined value, and the damping force is lower and softer than when the frequency is low.

[0235] In addition, when the piston speed is high, that is, equal to or higher than a predetermined value, the partition disc 314 is largely deflected and abuts against the protruding portion 89 of the valve base 25, and in a state in which further deformation is suppressed, the opening / closing disc 152E is deformed and separated from the partition disc 314. In other words, the relief mechanism 258E opens. At the same time, the outer peripheral tapered plate portion 162E of the conical spring 153E is deformed and separated from the partition disc 314. In other words, the relief mechanism 331 opens. As a result, the oil L in the variable chamber 252E flows into the second chamber 49 (see FIG. 2) through the second passage 221E including the variable chamber 220E. Note that, the opening / closing disc 152E is abutted against the disc 311 during the above-mentioned deformation, and thus further deformation is suppressed.

[0236] During the compression stroke, the pressure in the second chamber 49 (see FIG. 2) becomes higher than the pressure in the reservoir chamber 18, and the oil L in the second chamber 49 (see FIG. 2) is introduced into the second passage 221E and flows into the reservoir chamber 18 via the second damping force generating mechanism 225. In addition, the oil L in the second chamber 49 (see FIG. 2) is introduced into the variable chamber 220E of the pressure accumulating mechanism 251E, deforming the partition member 255E and expanding the variable chamber 220E. At that time, the oil L in the contracting variable chamber 252E is discharged into the reservoir chamber 18 via the fourth passage 241E.

[0237] In the compression stroke when the piston frequency is lower than a predetermined value, the stroke of the piston 45 (see FIG. 1) is large, so that in the early stage of the introduction of the oil L from the second chamber 49 (see FIG. 2) into the variable chamber 220E, the partition member 255E is largely deflected, and the outer peripheral tapered plate portion 162E of the conical spring 153E is brought into contact with the valve disc 154E, suppressing further deformation. As a result, the volume of the variable chamber 220E is in a state of not changing, and the variable chamber 220E cannot absorb the increase in the amount of oil L introduced. Then, the pressure in the variable chamber 220E rises to a high pressure, and the force pushing the second damping disc valve 222E in the opening direction becomes strong. Therefore, the second damping disc valve 222E opens, and the oil L flows into the reservoir chamber 18 through the gap with the outer seat 88. Therefore, in the compression stroke when the piston frequency is low and lower than a predetermined value, the damping force characteristic is the same as that in the case where there is no pressure accumulation mechanism 251E.

[0238] On the other hand, in the compression stroke when the piston frequency is equal to or higher than a predetermined value, the stroke of the piston 45 (see FIG. 1) is small, and therefore the volume of the oil L introduced from the second chamber 49 (see FIG. 2) into the variable chamber 220E is small, and the partition disc 314 is easily deformed with a small amount of deflection. Therefore, most of the increase in the oil L introduced from the second chamber 49 (see FIG. 2) into the variable chamber 220E is absorbed by the deflection of the partition member 255E. Therefore, the variable chamber 220E is at low pressure, and the opening pressure of the second damping disc valve 222E does not increase. Therefore, when the piston frequency is high frequency, the damping force is lower and softer than when the piston frequency is low frequency.

[0239] The shock absorber 11E and its body valve 30E of the sixth embodiment have the same effects as those of the first embodiment.

[0240] The structures of the first to sixth embodiments can be applied to various structures as long as they have a first passage in which the flow of the working fluid occurs due to the movement of the piston in one direction, a second passage in which the flow of the working fluid occurs due to the movement of the piston in the other direction, a first damping valve for opening and closing the first passage, and a second damping disc valve for opening and closing the second passage. That is, in the first to sixth embodiments, the second damping disc valves 222, 222A-222E and the pressure accumulation mechanisms 251, 251A-251E are arranged in a stacked manner on the reservoir chamber 18 side of the body valves 30, 30A-30E, but for example, the second damping disc valves 222, 222A-222E and the pressure accumulation mechanisms 251, 251A-251E may be arranged in a stacked manner on the second chamber 49 side of the body valve. The structures of the first to sixth embodiments can also be applied to the piston 45 (see FIG. 1). In this case, the second damping disc valves 222, 222A-222E and the pressure accumulation mechanisms 251, 251A-251E may be arranged in a stacked manner on the first chamber 48 side of the piston 45, or the second damping disc valves 222, 222A-222E and the pressure accumulation mechanisms 251, 251A-251E may be arranged in a stacked manner on the second chamber 49 side of the piston 45. [Industrial Applicability]

[0241] According to the above aspects of the present invention, it is possible to provide a shock absorber and a damping valve device capable of suppressing the generation of abnormal noise, and thus the industrial applicability is great. [Explanation of symbols]

[0242] 11, 11A to 11E... shock absorber, 17... cylinder, 18... reservoir chamber, 30, 30A to 30E... body valve (damping valve device), 45... piston, 49... second chamber, 88... outer seat (seat), 153, 153E... conical spring, 154, 154E... valve disc, 211... first passage, 212... first damping valve, 220, 220A to 220E... variable chamber, 22 1, 221A to 221E...second passage, 222, 222C to 222E...second damping disc valve, 231...third passage, 241, 241C, 241E...fourth passage (communicating passage), 251, 251A to 251E...accumulator mechanism, 252, 252A to 252E...variable chamber, 255, 55A to 255E...partition member, 258, 258B, 258D, 258E, 331...relief mechanism.

Claims

1. a cylinder in which a working fluid is sealed; a piston fitted in the cylinder to partition the interior of the cylinder; a first passage and a second passage through which the flow of the working fluid occurs due to the movement of the piston; a first damping valve that applies resistance to the flow of the hydraulic fluid from the upstream chamber to the downstream chamber of the first passage by unidirectional movement of the piston; a second damping disc valve that resists the flow of the hydraulic fluid from the upstream chamber to the downstream chamber of the second passage in response to the movement of the piston in the other direction; an orifice that restricts the flow of the working fluid in the second passage; a partition member in which a radially inner side and a radially outer side of the second damping disc valve abut against each other, forming a variable chamber between the second damping disc valve and the partition member, and which operates to change the volume of the variable chamber by moving in response to a pressure difference between an upstream chamber and a downstream chamber of the variable chamber; have buffer.

2. 2. The shock absorber according to claim 1, wherein the orifice is formed in the second damping disc valve.

3. The partition member is formed of a disc spring, 3. The shock absorber according to claim 2, wherein the volume of the variable chamber formed between the piston and the second damping disc valve is increased during an extension stroke, which is the movement of the piston in the other direction, and the volume of the variable chamber is reduced during a compression stroke, which is the movement of the piston in one direction.

4. 4. The shock absorber according to claim 1, further comprising a relief mechanism that operates to allow the working fluid to flow in the variable chamber after the pressure in the variable chamber reaches a predetermined value.

5. 2. The shock absorber according to claim 1, wherein the second damping disc valve is provided in a body valve.

6. 3. The shock absorber according to claim 2, wherein the second damping disc valve is provided in a body valve.

7. 4. The shock absorber according to claim 3, wherein the second damping disc valve is provided in a body valve.

8. 5. The shock absorber according to claim 4, wherein the second damping disc valve is provided in a body valve.

9. A damping valve device that is connected to a cylinder in which a working fluid is sealed, a first passage and a second passage through which the flow of the working fluid occurs due to the movement of the piston in the cylinder; a first damping valve that applies resistance to the flow of the hydraulic fluid from the upstream chamber to the downstream chamber of the first passage by unidirectional movement of the piston; a second damping disc valve that provides resistance to the flow of the hydraulic fluid from the upstream chamber to the downstream chamber of the second passage in response to movement of the piston in the other direction; an orifice that restricts the flow of the working fluid in the second passage; a partition member in which a radially inner side and a radially outer side of the second damping disc valve abut against each other, forming a variable chamber between the second damping disc valve and the partition member, and which operates to change the volume of the variable chamber by moving in response to a pressure difference between an upstream chamber and a downstream chamber of the variable chamber; have Damping valve device.

Images