JP2014194259A - Buffer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a buffer capable of acquiring a satisfactory damping force property.SOLUTION: A buffer comprises a plurality of annular discs 71A, 72, 71B, 74, 75 and 76 laminated on an inner seat 63 and an outer seat 64. The buffer comprises: an intermediate chamber 125 formed by providing a notch on an inner peripheral side at one part of these annular discs 71A, 72, 71B, 74, 75 and 76; an introduction orifice 123 formed between an opening of a working fluid flow passage 53 and the intermediate chamber 125; a back pressure chamber 129 comprising an opening provided at least at one piece out of the plurality of annular discs 71A, 72, 71B, 74, 75 and 76 except for the ones on both ends; an intermediate passage 127 for communicating the back pressure chamber 129 and the intermediate chamber 125; and a fixed orifice 131 provided on a downstream side of the back pressure chamber 129. In the configuration, a flow passage area of the introduction orifice 123 is smaller than that of the fixed orifice 131.

Description

  The present invention relates to a shock absorber.

  Some shock absorbers have a flow path formed on the inner peripheral side of a valve engaged with a piston rod (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 4-151039

  In the shock absorber, it is desired to obtain a good damping force characteristic.

  Therefore, an object of the present invention is to provide a shock absorber capable of obtaining good damping force characteristics.

  In order to achieve the above object, the present invention is provided with a valve body having a working fluid channel through which a working fluid flows by sliding of a piston in a cylinder, and an opening of the working fluid channel of the valve body. A shaft portion protruding from the formed surface, an inner seat provided around the shaft portion of the valve body, an outer seat provided so as to surround the opening of the working fluid channel of the valve body, A plurality of annular discs that pass through the shaft portion and are stacked on the inner sheet and the outer sheet; and a fixing member that is provided on the shaft portion and sandwiches the plurality of annular discs in the axial direction with the inner sheet; An intermediate chamber formed by providing a notch on the inner peripheral side of a part of the plurality of annular disks, and formed between the opening of the working fluid flow path and the intermediate chamber Introduction A back pressure chamber comprising an opening provided in at least one of the plurality of annular discs other than the annular discs at both ends, an intermediate passage communicating the back pressure chamber and the intermediate chamber, and the back And a fixed orifice provided on the downstream side of the pressure chamber, and the flow area of the fixed orifice is smaller than that of the introduction orifice.

  According to the present invention, good damping force characteristics can be obtained.

It is sectional drawing which shows the shock absorber which concerns on 1st Embodiment of this invention. It is sectional drawing which shows the principal part of the buffer which concerns on 1st Embodiment of this invention. It is a top view which shows the annular disc of the buffer concerning a 1st embodiment of the present invention, (a) is the 1st annular disc, (b) is the 2nd annular disc, (c) is the 3rd annular disc, (d) Indicates a fourth annular disk, and (e) indicates a fifth annular disk. It is a fluid pressure circuit diagram of a buffer concerning a 1st embodiment of the present invention. It is a characteristic line figure which shows the damping force characteristic of the buffer which concerns on 1st Embodiment of this invention. It is sectional drawing of the principal part explaining the flow of the working fluid in the disk valve | bulb of the buffer which concerns on 1st Embodiment of this invention, (a) is the flow of a very low speed area, (b) is the flow of a low speed area. , (C) shows the flow in the middle and high speed range, respectively. It is sectional drawing which shows the principal part of the buffer which concerns on 2nd Embodiment of this invention. It is a top view which shows the spacer and annular disc of the buffer which concern on 2nd Embodiment of this invention, Comprising: (a) is a spacer, (b) is a 1st annular disc, (c) is a 2nd annular disc, (d ) Shows the third annular disk, and (e) shows the fourth annular disk. It is a top view which shows the modification of the spacer of the buffer which concerns on 2nd Embodiment of this invention.

“First Embodiment”
A shock absorber according to a first embodiment of the present invention will be described below with reference to FIGS.

  A shock absorber 11 according to the first embodiment shown in FIG. 1 is a hydraulic shock absorber in which an oil liquid is used as a working fluid. Specifically, the shock absorber 11 is used in a suspension device of a vehicle such as an automobile. The shock absorber 11 includes an inner cylinder 12, an outer cylinder 14 having a larger diameter than the inner cylinder 12 and coaxially disposed so as to form a reservoir chamber 13 between the inner cylinder 12 and the central axis of the inner cylinder 12. And a piston rod 15 having one axial side inserted into the inner cylinder 12 and the other axially extending to the outside from the inner cylinder 12 and the outer cylinder 14 and one end of the piston rod 15 connected to the inner A piston 18 is slidably fitted into the cylinder 12 and defines the inner cylinder 12 into two chambers 16 and 17. That is, the shock absorber 11 is a double cylinder type in which the cylinder 19 includes the inner cylinder 12 and the outer cylinder 14. The present invention is not limited to a double cylinder type, and can be used for a single cylinder type shock absorber, and can also be applied to a shock absorber using a damping force adjusting mechanism. It can also be applied to vessels.

  The piston rod 15 moves integrally with the piston 18 connected to one end, and the other end protrudes outside from the cylinder 19, that is, the inner cylinder 12 and the outer cylinder 14. The inner cylinder 12 is filled with an oil liquid as a working fluid, and the reservoir chamber 13 between the inner cylinder 12 and the outer cylinder 14 is filled with an oil liquid and a high-pressure gas as the working fluid. Will be. The reservoir chamber 13 may be filled with atmospheric pressure air instead of high-pressure gas.

  The shock absorber 11 includes a rod guide 20 disposed at an end position of the piston 19 on the projecting side of the piston rod 15 in the cylinder 19, and an end portion of the cylinder 19 that is inward and outward in the axial direction of the cylinder 19 (up and down direction in FIG. 1). A seal member 21 disposed outside the rod guide 20 (upward in the vertical direction in FIG. 1), and an inner side (in the vertical direction in FIG. 1) in the cylinder inner / outer direction than the seal member 21 and the seal member 21 A friction member 22 disposed between the rod guide 20 and a base valve 23 disposed at an end of the cylinder 19 opposite to the rod guide 20, the seal member 21 and the friction member 22 in the axial direction; ing.

  The rod guide 20, the seal member 21, and the friction member 22 all have an annular shape, and the piston rod 15 is slidably inserted into the inside thereof. The rod guide 20 supports the piston rod 15 so as to be movable in the axial direction while restricting its radial movement, and guides the movement of the piston rod 15. The seal member 21 is in sliding contact with the outer peripheral portion of the piston rod 15 that moves in the axial direction at the inner peripheral portion thereof, and the high-pressure gas and the oil liquid in the reservoir chamber 13 in the outer cylinder 14 Is prevented from leaking outside. The friction member 22 is slidably contacted with the outer peripheral portion of the piston rod 15 at the inner peripheral portion thereof to generate a frictional resistance on the piston rod 15, and is not intended for sealing.

  The outer cylinder 14 of the cylinder 19 includes a cylindrical body 25, a bottom 26 that closes one end of the body 25 opposite to the projecting side of the piston rod 15, and a projecting side of the piston rod 15 in the body 25. It has a substantially bottomed cylindrical shape having a locking portion 28 protruding radially inward from the position of the opening 27. A cover 29 is attached to the opening 27 side of the outer cylinder 14 so as to cover the locking portion 28 and the seal member 21.

  A base valve body 30 of the base valve 23 is disposed inside the bottom portion 26 of the outer cylinder 14. The inner cylinder 12 of the cylinder 19 has a cylindrical shape, and one end side in the axial direction is supported in a fitted state on the base valve body 30 of the base valve 23, and the other end side in the axial direction is fitted in the rod guide 20. It is supported.

  The base valve body 30 of the base valve 23 is formed with working fluid flow paths 31 and 32 capable of communicating the chamber 17 in the inner cylinder 12 and the reservoir chamber 13 between the outer cylinder 14 and the inner cylinder 12. Yes. In addition, a disc valve 33 as a compression side damping valve capable of opening and closing the inner working fluid flow path 31 is disposed on the bottom portion 26 side of the base valve body 30 and the outer working fluid flow path 32 can be opened and closed. A disk valve 34 as a valve is arranged on the side opposite to the bottom portion 26. These disc valves 33 and 34 are attached to the base valve body 30 by a head portion 36 at one end of a rivet 35 and a caulking portion 37 at the other end of the rivet 35 inserted into the base valve body 30 from the bottom 26 side.

  The disc valve 33 generates a damping force while allowing the oil liquid to flow from the chamber 17 to the reservoir chamber 13 through the passage hole (not shown) of the disc valve 34 and the working fluid flow path 31, while in the reverse direction. Regulates the flow of oil. On the contrary, the disc valve 34 allows the flow of oil from the reservoir chamber 13 to the chamber 17 through the working fluid flow path 32 without resistance, while restricting the flow of oil in the reverse direction. In other words, the disc valve 33 opens the working fluid flow path 31 when the piston rod 15 moves to the contraction side, the piston 18 moves to the chamber 17 side, and the pressure in the chamber 17 rises. It is a damping valve that occurs. The disk valve 34 opens the working fluid flow path 32 when the piston rod 15 moves to the extension side, the piston 18 moves to the chamber 16 side, and the pressure in the chamber 17 decreases. 13 is a suction valve that allows oil to flow from chamber 13 to chamber 17 without substantially generating a damping force. Note that the damping force on the extension side may be positively generated by the disk valve 34 as a check valve. Further, these disc valves 33 and 34 may be eliminated and used as orifices.

  The piston rod 15 includes a main shaft portion 38 having a constant diameter and an attachment shaft portion (shaft portion) 39 having a smaller diameter than the main shaft portion 38 at the end portion on the side inserted into the inner cylinder 12. A stacking portion 42 including the disc valve 41, the above-described piston 18 and a stacking portion 44 including the disc valve 43 are inserted into the mounting shaft portion 39 in this order from the main shaft portion 38 side. A nut 46 is screwed onto the mounting shaft portion 39 protruding from the nut. As a result, the end surface of the main shaft portion 38 on the mounting shaft portion 39 side and the nut 46 sandwich the laminated portion 42, the piston 18 and the laminated portion 44, whereby the laminated portion 42, the piston 18 and the laminated portion 44 are connected to the piston rod. 15 is attached.

  The piston 18 has an annular piston valve body (valve body) 50 in which an insertion hole 49 through which the mounting shaft portion 39 of the piston rod 15 is inserted is formed at the center, and an outer cylinder mounted on the outer peripheral surface of the piston valve body 50. 12 and an annular belt-like sliding contact member 51 that is in sliding contact with the inside. The piston valve body 50 is formed with working fluid flow paths 52 and 53 capable of communicating between the chamber 17 on the bottom 26 side in the inner cylinder 12 and the chamber 16 on the opposite side of the bottom 26. The working fluid flow path 52 has a chamber 16 side opened to the inside in the radial direction of the piston valve body 50, and a chamber 17 side opened to the outside in the radial direction of the piston valve body 50. The working fluid channel 53 has a chamber 16 side that opens to the outside in the radial direction of the piston valve body 50, and a chamber 17 side that opens to the inside of the piston valve body 50 in the radial direction. The piston valve body 50 is provided with a laminated portion 42 including the above-described disc valve 41 on the axial chamber 17 side so that the working fluid flow path 52 can be opened and closed. In addition, a laminated portion 44 including the above-described disk valve 43 is disposed so that the working fluid flow path 53 can be opened and closed.

  When the piston rod 15 moves to the contraction side to increase the amount of entry into the cylinder 19, the piston 18 that moves integrally with the piston rod 15 slides in the cylinder 19 to increase the volume of the chamber 16 and increase the chamber 17. Reduce the volume of the. At this time, the fluid in the chamber 17 is restricted from flowing through the working fluid flow path 53 by the stacked portion 44, flows through the working fluid flow path 52, and is discharged to the chamber 16 through the stacked portion 42. On the other hand, when the piston rod 15 moves to the extending side to increase the amount of protrusion from the cylinder 19, the piston 18 that moves integrally with the piston rod 15 slides in the cylinder 19 to increase the volume of the chamber 17. Reduce the volume of 16. At this time, the fluid in the chamber 16 is restricted from flowing in the working fluid flow path 52 by the stacked portion 42, flows in the working fluid flow path 53, and is discharged to the chamber 17 through the stacked portion 44.

  The working fluid flow path 52, the base 54 at the end of the piston valve body 50 on the side of the laminated portion 42 in the axial direction, and the laminated portion 42 move the working fluid flow path 52 when the piston rod 15 moves to the contraction side. A contraction-side damping force generating mechanism 55 that adjusts the flow rate of the oil liquid that flows and flows from the chamber 17 to the chamber 16 by the laminated portion 42 to generate a damping force is configured. The working fluid flow path 53, the base 56 at the end of the piston valve body 50 on the side of the laminated portion 44 in the axial direction, and the laminated portion 44 move when the piston rod 15 moves to the extending side. 53, an extension-side damping force generation mechanism 57 that generates a damping force by adjusting the flow rate of the oil liquid flowing through the chamber 53 from the chamber 16 to the chamber 17 by the laminated portion 44 is configured.

  Since the compression-side damping force generation mechanism 55 and the expansion-side damping force generation mechanism 57 have the same structure, the expansion-side damping force generation mechanism 57 will be described in detail below as an example.

  As shown in FIG. 2, an annular bottom surface portion 62 provided with an opening 61 of the working fluid flow channel 53 is provided at the base portion 56 of the piston valve body 50 constituting the extension-side damping force generation mechanism 57. It is formed along the axis orthogonal direction of the body 50. Further, an annular inner sheet 63 that protrudes closer to the laminated portion 44 in the axial direction than the bottom surface portion 62 is formed on the base portion 56 so as to surround the insertion hole 49 on the inner side in the radial direction of the bottom surface portion 62. Yes. In addition, an annular outer sheet 64 that protrudes toward the laminated portion 44 in the axial direction from the bottom surface portion 62 is formed on the base portion 56 so as to surround the bottom surface portion 62 outside the bottom surface portion 62 in the radial direction. . Therefore, the outer seat 64 is provided so as to surround the opening 61 of the working fluid channel 53 of the piston valve body 50. The leading end surface in the protruding direction of the inner seat 63 and the leading end surface in the protruding direction of the outer seat 64 are both along the axis orthogonal direction of the piston valve body 50. The leading end surface of the outer sheet 64 is higher in the protruding direction than the leading end surface of the inner sheet 63.

  A mounting shaft portion 39 of the piston rod 15 protrudes from an end surface in the axial direction of the piston valve body 50 including the bottom surface portion 62 provided with the opening 61 of the working fluid flow path 53. An inner seat 63 is provided around the mounting shaft 39 of the piston valve body 50.

  The stacking portion 44 includes, in order from the piston valve body 50 side in the axial direction, a spacer 70, and more specifically, six first annular disks 71A, second annular disks 72, third annular disks 71B, and fourth annular disks. 74, a fifth annular disk 75 and a sixth annular disk 76, a spacer 77, a regulating member 78, and a fixing member 79.

  The spacer 70 has a perforated disk shape in which a circular through hole 81 for fitting the mounting shaft portion 39 in a substantially space-free state is formed at the center in the radial direction, and the outer diameter is the inner sheet 63. It is almost the same diameter as the outer diameter. The spacer 70 contacts the inner sheet 63 and does not contact the outer sheet 64.

  The first annular disk 71A has a perforated disk shape in which a non-circular through hole 84A is formed at the center in the radial direction, and has an outer diameter larger than that of the spacer 70 and an outer diameter of the outer sheet 64. The diameter is larger than. As shown in FIG. 3 (a), the through hole 84A has a plurality of circumferential portions (specifically, three locations) and fitting portions 85A for fitting the mounting shaft portions 39 in a state having almost no gap. Have. The through hole 84A has a plurality of (specifically, three) cutout portions 86A that extend radially outward from between the fitting portions 85A and 85A adjacent in the circumferential direction. Each of 86A has a plurality of locations (specifically, two locations), and inner concave portions 87A that are recessed radially outward. The inner concave portion 87A has a narrow width portion 88A having a narrow width in the circumferential direction of the through hole 84A on the cutout portion 86A side, and a width in the circumferential direction of the through hole 84A on the side opposite to the cutout portion 86A is smaller than the narrow width portion 88A. Is also a wide part 89A.

  The second annular disk 72 shown in FIG. 3B has a perforated disk shape in which a non-circular through hole 92 is formed in the center in the radial direction, and the outer diameter is as shown in FIG. It has the same diameter as the first annular disk 71A shown. The central through-hole 92 has fitting portions 93 that are fitted at a plurality of locations (specifically, three locations) in the circumferential direction and fit the attachment shaft portion 39 in a substantially space-free state. Further, the through hole 92 has a plurality of (specifically, three) cutout portions 94 extending radially outward from between the fitting portions 93 adjacent to each other in the circumferential direction.

  The third annular disk 71B shown in FIG. 3 (c) is a common part having the same shape as the first annular disk 71A shown in FIG. 3 (a). Similar to the first annular disk 71A, the third annular disk 71B has a through hole 84B formed in the center in the radial direction. The through hole 84B includes a fitting part 85B, a notch part 86B, and an inner concave part 87B. The inner concave portion 87B has a narrow portion 88B and a wide portion 89B.

  The fourth annular disk 74 shown in FIG. 3D has a non-circular through hole 105 formed in the center in the radial direction, and a plurality of (specifically, five) shafts around the through hole 105. It has a perforated disk shape with an opening 106 penetrating in the direction, and the outer diameter is the same as that of the first annular disk 71A shown in FIG. The central through-hole 105 has a fitting portion 107 that is provided at a plurality of locations (specifically, three locations) in the circumferential direction and that fits the mounting shaft portion 39 in a substantially space-free state. The through-hole 105 has a plurality of (specifically, three) cutout portions 108 that extend radially outward from between the fitting portions 107 adjacent to each other in the circumferential direction. The openings 106 each have a sector shape, and are aligned in the circumferential direction of the fourth annular disk 74 with the radial position of the fourth annular disk 74 aligned.

  The fifth annular disk 75 shown in FIG. 3 (e) has a perforated disk shape in which a circular through hole 111 is formed in the center in the radial direction so that the mounting shaft portion 39 is fitted with almost no gap. Therefore, the outer diameter is the same as that of the first annular disk 71A shown in FIG. The fifth annular disk 75 has an outer concave portion 112 that is recessed radially inward from a plurality of locations (specifically, five locations) in the circumferential direction of the outer peripheral edge. The outer concave portion 112 is a narrow portion 113 having a narrow width in the circumferential direction of the fifth annular disc 75 on the outer peripheral edge side, and a width in the circumferential direction of the fifth annular disc 75 is wide on the side opposite to the outer peripheral edge portion. The wide portion 114 is wider than the narrow portion 113.

  The sixth annular disk 76 shown in FIG. 2 has a perforated disk shape in which a circular through hole 116 is formed in the center in the radial direction so that the mounting shaft portion 39 is fitted with almost no gap. The outer diameter is the same as that of the first annular disk 71A and the like.

  The spacer 77 has a perforated disk shape in which a circular through hole 117 that fits the mounting shaft portion 39 in a substantially space-free state is formed at the center in the radial direction. Has a slightly smaller diameter.

  The regulating member 78 has a perforated disk shape in which a circular through hole 118 for fitting the attachment shaft portion 39 in a state with almost no gap is formed at the center in the radial direction, and the outer diameter is the first. The diameter is slightly smaller than the annular disk 71A or the like. When the sixth annular disk 76 is deformed, the restricting member 78 restricts the deformation when it comes into contact with the sixth annular disk 76.

  The fixing member 79 has a perforated disk shape in which a circular through hole 119 for fitting the attachment shaft portion 39 in a substantially space-free state is formed at the center in the radial direction, and the outer diameter is the spacer 70. The diameter is slightly larger than. The fixing member 79 includes a spacer 70, a plurality of annular disks 71 </ b> A, 72, 71 </ b> B, 74, 75, 76, a spacer 77, a restriction member 78, and an inner seat 63 of the piston valve body 50 when the nut 46 is fastened. Sandwich in the axial direction.

  In addition, as will be described later, a plurality of, specifically, six annular disks 71A, 72, 71B, 74, and 75 that are continuously stacked and deform when the oil liquid flows into the chamber 17 through the working fluid flow path 53. , 76 constitute the disc valve 43. That is, the disc valve 43 is not configured for the spacers 70 and 77 and the fixing member 79 that are not deformed and the regulating member 78 that is not continuously laminated. The annular disks 71A, 72, 71B, 74, 75, and 76 constituting the disk valve 43 are laminated on the inner sheet 63 and directly on the outer sheet 64 via the spacer 70.

  As described above, the spacer 70, the first annular disc 71A, the second annular disc 72, the third annular disc 71B, the fourth annular disc 74, the fifth annular disc 75, while providing the mounting shaft 39 inside, The sixth annular disk 76, the spacer 77, the regulating member 78, and the fixing member 79 are sequentially laminated on the piston valve body 50 in this order to constitute the laminated portion 44.

  Hereinafter, a set state of the plurality of annular disks 71A, 72, 71B, 74, 75, and 76 constituting the disk valve 43 (a state in which oil does not flow into the working fluid flow path 53) will be described. In the following description, the radial direction of each of the annular disks 71A, 72, 71B, 74, 75, 76 is the disk radial direction, the axial direction is the disk axial direction, and the circumferential direction is the disk circumferential direction.

  The first annular disc 71 </ b> A is in contact with the outer sheet 64 and closes the gap with the outer sheet 64. The first annular disc 71 </ b> A forms a chamber 121 in which the working fluid flow path 53 opens between the outer sheet 64, the inner sheet 63, the bottom surface part 62, and the spacer 70. In a state where the first annular disk 71A is in contact with the outer sheet 64, the communication of the chamber 121, that is, the working fluid flow path 53, to the chamber 17 through the gap between the first annular disk 71A and the outer sheet 64 is restricted. . By changing the thickness of the spacer 70, the amount of bending of the first annular disc 71A in the set state on the outer sheet 64 changes, and the set load changes.

  In the first annular disk 71A, the notch 86A shown in FIG. 3A is aligned with the notch 94 of the second annular disk 72 shown in FIG. 3B in the disk radial direction. The inner concave portion 87A of the first annular disk 71A is covered with the spacer 70 shown in FIG. 2 at the inner side in the disk radial direction of the narrow part 88A on one side in the disk axial direction, and the entire other side in the disk axial direction is the second annular shape. Covered with a disk 72. A portion surrounded by the inner concave portion 87A of the first annular disk 71A shown in FIG. 3A and the spacer 70 and the second annular disk 72 shown in FIG. A portion surrounded by the narrow portion 88A of the inner concave portion 87A shown in FIG. 3A and the spacer 70 and the second annular disk 72 shown in FIG. ing. The introduction orifice 123 has a disk radial direction outer side portion and a wide portion 89A of the narrow portion 88A on one side in the disc axial direction of the first annular disc 71A shown in FIG. 3A facing the chamber 121 shown in FIG. Therefore, the introduction orifice 123 opens to the chamber 121 at this portion.

  The clearance between the cutout portion 94 of the second annular disk 72 and the mounting shaft portion 39 shown in FIG. 3B is the clearance between the cutout portion 86A of the first annular disc 71A and the mounting shaft portion 39 shown in FIG. 3, and communicates with the gap between the cutout portion 86 </ b> B of the third annular disc 71 </ b> B and the mounting shaft portion 39 shown in FIG. 3C, and further, the cutout portion 108 of the fourth annular disc 74 shown in FIG. 3D. And the mounting shaft portion 39 communicate with each other. These gaps form an intermediate chamber 125 shown in FIG. In this intermediate chamber 125, the narrow portion 88A of the inner concave portion 87A of the first annular disk 71A shown in FIG. 3A faces, so that the side opposite to the chamber 121 of the introduction orifice 123 shown in FIG. It is open. The intermediate chamber 125 is entirely covered with a spacer 70 on one side in the disk axial direction, and is covered with a fifth annular disk 75 on the other side in the disk axial direction. That is, the intermediate chamber 125 has notches 86A, 94, 86B on the inner peripheral side of the annular disks 71A, 72, 71B, 74 which are a part of the plurality of annular disks 71A, 72, 71B, 74, 75, 76. 108, and the introduction orifice 123 is formed between the intermediate chamber 125 and the opening 61 of the working fluid channel 53 as shown in FIG.

  The inner concave portion 87B of the third annular disk 71B shown in FIG. 3C has a narrow portion 88B facing the intermediate chamber 125 shown in FIG. The inner concave portion 87 </ b> B shown in FIG. 3C is an intermediate passage 127 that opens into the intermediate chamber 125 shown in FIG. 2, and this intermediate passage 127 opens into the intermediate chamber 125. The intermediate passage 127 is entirely covered with the second annular disk 72 on one side in the disk axial direction, and is covered with a fourth annular disk 74 on the inner side in the disk radial direction on the other side in the disk axial direction. A portion surrounded by the narrow portion 88B of the inner concave portion 87B shown in FIG. 3C and the second annular disc 72 and the fourth annular disc 74 shown in FIG. 2 is the minimum passage area portion of the intermediate passage 127. ing. Since the first annular disk 71A and the third annular disk 71B having the same shape are used, the minimum flow area of the introduction orifice 123 and the minimum flow area of the intermediate passage 127 are equal. In the inner concave portion 87B of the third annular disc 71B shown in FIG. 3C, the outer portion in the disc radial direction of the narrow portion 88B and the wide portion 89B face the opening 106 of the fourth annular disc 74.

  The inside of the opening 106 of the fourth annular disk 74 is a back pressure chamber 129 shown in FIG. 2, and therefore the intermediate passage 127 is an inner concave part 87B of the third annular disk 71B shown in FIG. The narrow portion 88B has an outer portion in the disk radial direction and a wide portion 89B, which opens to the back pressure chamber 129 shown in FIG. 2, and allows the back pressure chamber 129 and the intermediate chamber 125 to communicate with each other. In the back pressure chamber 129, one side in the disk axial direction is covered with the third annular disk 71 </ b> B, and the other side in the disk axial direction is covered with the fifth annular disk 75. The back pressure chamber 129 is formed from an opening 106 provided in the fourth annular disk 74 that is at least one of the plurality of annular disks 71A, 72, 71B, 74, 75, 76 other than the annular disks 71A, 76 at both ends. It has become.

  The outer concave portion 112 of the fifth annular disc 75 shown in FIG. 3 (e) has a wide portion 114 and a radially inner portion of the narrow portion 113 of the fourth annular disc 74 shown in FIG. 3 (d). The sixth annular disk facing the opening 106 is covered with a fourth annular disk 74 on the disk radial direction outer side of the narrow part 113 on one side in the disk axial direction, and the entire other side in the disk axial direction is shown in FIG. 76. A portion surrounded by the narrow portion 113 of the outer concave portion 112 shown in FIG. 3 (e) and the fourth annular disc 74 and the sixth annular disc 76 shown in FIG. 2 is a fixed orifice 131, and FIG. The inner portion in the disk radial direction of the wide portion 114 and the narrow portion 113 shown in FIG. 3 (e) facing the opening 106 of the fourth annular disc 74 shown in d) becomes a part of the back pressure chamber 129 shown in FIG. ing. The fixed orifice 131 faces the chamber 17, so that the fixed orifice 131 opens on the one hand to the chamber 17 and on the other hand to the back pressure chamber 129. Here, the flow area of the fixed orifice 131 is set to be smaller than that of the introduction orifice 123.

  When the oil liquid flows from the working fluid flow path 53 to the chamber 17 through the chamber 121, the introduction orifice 123, the intermediate chamber 125, the intermediate passage 127, the back pressure chamber 129, and the fixed orifice 131 with respect to the above set state. When the flow rate is increased, the sixth annular disk 76 is deformed to move away from the fifth annular disk 75 and the fourth annular disk 74, which together formed the fixed orifice 131, and expand the flow path. The outer concave portion 112 shown in FIG. 3 (e) of the fifth annular disc 75, the fourth annular disc 74 shown in FIG. 3 (d) covering one side in the disc axial direction, the disc axial direction of the outer concave portion 112, etc. The sixth annular disk 76 shown in FIG. 2 that opens and closes the side serves as a first valve portion 133 in which the flow path area changes. In the first valve portion 133, the pressure in the back pressure chamber 129 acts on the sixth annular disc 76 in the opening direction.

  Further, when the flow rate flowing through the working fluid flow path 53 is further increased, the annular disks 71A, 72, 71B, 74, 75, and 76 are deformed and separated from the outer sheet 64, and the gap between the first annular disk 71A and the outer sheet 64 is increased. The oil liquid flows into the chamber 17 through. At that time, the annular disks 71A, 72, 71B, 74, 75, and 76 change the flow path area of the gap between the first annular disk 71A and the outer sheet 64 according to the deformation amount. The annular discs 71A, 72, 71B, 74, 75, and 76 and the outer sheet 64 form the second valve portion 134 in which the flow path area changes. In the second valve portion 134, the pressure in the back pressure chamber 129 acts on the annular disks 71A, 72, 71B in the closing direction, that is, in the direction of the outer seat 64.

  The above hydraulic circuit diagram of the shock absorber 11 is as shown in FIG. In the extension-side damping force generation mechanism 57, the introduction orifice 123 is disposed on the chamber 16 side, the intermediate chamber 125 is disposed on the opposite side of the introduction orifice 123 from the chamber 16, and the intermediate chamber 125 is opposite to the introduction orifice 123. An intermediate passage 127 is disposed on the opposite side of the intermediate passage 127 from the intermediate chamber 125. The back pressure chamber 129 is connected to the chamber 17 via the fixed orifice 131 or the first valve portion 133, and the pressure of the back pressure chamber 129 is applied to the second valve portion 134. In contrast, the contraction-side damping force generation mechanism 55 has an introduction orifice 123 disposed on the chamber 17 side, and the back pressure chamber 129 is connected to the chamber 16 via the fixed orifice 131 or the first valve portion 133. It is connected.

  Next, from the set state described above, the operation on the extending side for flowing the oil liquid from the chamber 16 to the chamber 17 through the working fluid flow path 53 and the generated damping force characteristic (shown by a solid line in FIG. 5) will be described.

  In the very low speed range where the piston speed indicated by 0 to v1 in FIG. 5 is slow, as shown in FIG. 6A, the oil liquid flowing toward the chamber 17 side through the working fluid flow path 53 has a very low flow rate. 121 flows into the back pressure chamber 129 through the introduction orifice 123, the intermediate chamber 125, and the intermediate passage 127 of the disc valve 43 in the set state described above, and enters the chamber from the fixed orifice 131 provided on the downstream side of the back pressure chamber 129. 17 is discharged. In this flow path, the flow area of the fixed orifice 131 is the smallest, and in the very low speed range 0 to v1 shown in FIG. 5, the narrowest fixed orifice 131 causes the orifice characteristics (the damping force is approximately proportional to the square of the piston speed). A) damping force is generated. In the very low speed range 0 to v1, the damping force is determined by the flow path area of the narrowest fixed orifice 131. Therefore, the damping force can be adjusted by the flow path area of the fixed orifice 131.

  Then, when the piston speed increases and the flow rate of flowing oil increases, the pressure in the back pressure chamber 129 increases, so the differential pressure between the back pressure chamber 129 and the chamber 17 increases, as shown in FIG. The sixth annular disc 76 above the fourth annular disc 74 and the fifth annular disc 75 forming the back pressure chamber 129 is deformed by the differential pressure and opens. That is, the first valve part 133 is opened. This is the valve opening point A shown in FIG. The valve opening pressure at the valve opening point A is determined by the rigidity (number and plate thickness) of the fourth annular disk 74 and the sixth annular disk 76 above the fifth annular disk 75, which together form the back pressure chamber 129, and the spacer 70. The flow rate point contributes to the area of the fixed orifice 131. The higher the rigidity of the sixth annular disk 76, the higher the valve opening pressure. The smaller the flow area of the fixed orifice 131, the lower the flow rate, the higher the pressure in the back pressure chamber 129, and the differential pressure (back pressure) around the fixed orifice 131. The differential pressure between the chamber 129 and the chamber 17 increases, and the valve opening point A moves to the low speed side (low flow rate side).

  After the first valve portion 133 is opened, the flow rate becomes a low flow rate with a larger flow rate than the very low speed range 0 to v1, and the piston speed becomes a low speed range v1 to v2, and the valve characteristics (the damping force is almost equal to the piston speed). (Proportional) damping force is generated. The inclination of the damping force characteristic in the low speed region v1 to v2 (ratio of the increase in the damping force with respect to the increase in the piston speed) is the fourth annular shape forming the back pressure chamber 129 and the flow area of the introduction orifice 123 and the intermediate passage 127. It is determined by the rigidity (number of sheets and plate thickness) of the sixth annular disc 76 above the disc 74 and the fifth annular disc 75. If the flow passage area of the introduction orifice 123 or the intermediate passage 127 is reduced, the inclination is increased. If the passage areas of both the introduction orifice 123 and the intermediate passage 127 are increased, the inclination is reduced. Even if the rigidity of the sixth annular disk 76 is increased, the inclination is increased. When the flow rate further increases, the differential pressure between the chamber 121 and the chamber 17 determined by the flow area of the introduction orifice 123, the intermediate passage 127 and the first valve portion 133, and the rigidity of the sixth annular disk 76 increases, and FIG. As shown in (c), the entire annular discs 71A, 72, 71B, 74, 75, 76 are deformed and opened. That is, the second valve portion 134 is opened in addition to the first valve portion 133. This is the valve opening point B shown in FIG.

  The valve opening pressure at the valve opening point B is determined by the differential pressure between the chamber 121 and the chamber 17 determined by the flow area of the introduction orifice 123, the intermediate passage 127 and the first valve portion 133, and the rigidity of the sixth annular disc 76, and It is determined by the rigidity (number and thickness) of the two annular disks 72 and the preload step between the spacer 70 and the outer sheet 64. The valve opening pressure increases due to increased rigidity and increased preload steps. The flow rate point at which the valve is opened is determined by the flow area of the introduction orifice 123, the intermediate passage 127 and the first valve portion 133 and the rigidity of the sixth annular disk 76.

  After the second valve portion 134 is opened, the flow rate becomes a medium / high flow rate with a larger flow rate than the low speed range v1 to v2, and the piston speed becomes a medium / high speed range v2 and the valve characteristics (the damping force is almost proportional to the piston speed). A) damping force is generated. In the middle to high speed range v2 to 2, the inclination is determined by the rigidity of the entire disc valve 43 and the diameter of the working fluid flow path 53 as in the normal valve.

  As described above, the gradients of the damping force characteristics, the valve opening point A and the valve opening point B in the very low speed range 0 to v1, the low speed range v1 to v2, and the medium and high speed range v2 are set to the annular disks 71A, 72, 71B, 74, and 75. , 76 and the orifice area can be adjusted respectively. For example, by changing only the fixed orifice 131, the damping force in the very low speed range 0 to v1 and the low speed range v1 to v2 can be adjusted without changing the overall characteristics. Specifically, for example, when the flow path area of the fixed orifice 131 is reduced, a normal low speed range 0 to v1 and a low speed range v1 to v2 damping force is generated only by the orifice characteristic of the fixed orifice indicated by a broken line in FIG. The damping force can be increased compared to the case of the shock absorber. Further, in the medium-high speed region v2 where the piston speed is higher than the low speed regions v1 to v2, the first annular disk 71A is separated from the outer seat 64 in addition to the sixth annular disk 76 being separated from the fifth annular disk 75. That is, both the first valve portion 133 and the second valve portion 134 are opened, and the oil liquid flows, and the piston speed increases as compared with the case of a normal shock absorber indicated by a broken line in FIG. The rate of increase in damping force can be kept low.

  As described above, according to the shock absorber 11 according to the first embodiment, since the degree of freedom in tuning is improved, a good damping force characteristic can be obtained. Accordingly, it is possible to obtain a damping force characteristic suitable for the vehicle type of the mounted vehicle.

“Second Embodiment”
A shock absorber according to a second embodiment of the present invention will be described with reference to FIGS. 7 to 9 focusing on the differences from the first embodiment. In addition, about the site | part which is common in 1st Embodiment, it represents with the same name and the same code | symbol.

  In the second embodiment, as shown in FIG. 7, a spacer 170, a first annular disk 171A, a second annular disk 171B, a third annular disk 173, a fourth annular disk 174, and a fifth annular disk 175A are provided in the stacked portion 44. And a sixth annular disk 175B is used.

  The spacer 170 has a perforated disk shape in which a non-circular through hole 184 is formed in the center in the radial direction, and the outer diameter is larger than the outer diameter of the inner sheet 63 and is larger than the inner diameter of the outer sheet 64. It is getting smaller. The spacer 170 contacts the inner sheet 63 and does not contact the outer sheet 64. As shown in FIG. 8A, the through-hole 184 has a plurality of circumferential portions (specifically, three locations), and fitting portions 185 that fit the mounting shaft portions 39 in a substantially gap-free state. Have. The through-hole 184 has a plurality of (specifically, three) cutout portions 186 extending radially outward from between the fitting portions 185 adjacent to each other in the circumferential direction and the cutout portions. Each of 186 has an inner concave portion 187 that is recessed in a plurality of locations (specifically, four locations) radially outward. The inner concave portion 187 is a narrow portion 188 having a narrow width in the circumferential direction of the through hole 184 on the notch portion 186 side, and a width in the circumferential direction of the through hole 184 is narrower than the narrow portion 188 on the side opposite to the notch portion 186. The wide portion 189 is also wide.

  The first annular disk 171A shown in FIG. 8B has a perforated disk shape in which a non-circular through hole 192A is formed in the center in the radial direction, and the outer diameter is larger than that of the spacer 170. The outer diameter of the outer sheet 64 is larger. The central through-hole 192A has fitting portions 193A that are fitted at a plurality of locations (specifically, three locations) in the circumferential direction and fit the attachment shaft portion 39 in a substantially space-free state. Further, the through hole 192A has a plurality of (specifically, three) cutout portions 194A that spread radially outward from between the fitting portion 193A and the fitting portion 193A adjacent in the circumferential direction.

  The second annular disk 171B shown in FIG. 8C is a common part having the same shape as the first annular disk 171A. Similar to the first annular disk 171A, the second annular disk 171B has a through hole 192B formed in the center in the radial direction, and the through hole 192B has a fitting part 193B and a notch part 194B.

  The third annular disk 173 shown in FIG. 8D has a non-circular through hole 196 formed in the center in the radial direction, and a plurality of (specifically, two) shafts around the through hole 196. It has a perforated disk shape with an opening 197 penetrating in the direction, and the outer diameter is the same as that of the first annular disk 171A and the like. The central through-hole 196 has a fitting portion 198 that is fitted at a plurality of locations (specifically, three locations) in the circumferential direction and that fits the attachment shaft portion 39 in a substantially space-free state. Further, the through hole 196 has a plurality of (specifically, three) notches 199 extending radially outward from between the fitting portions 198 adjacent to each other in the circumferential direction and the fitting portion 198, Each of the cutout portions 199 has an inner concave portion 200 that is recessed at a plurality of locations (specifically, at three locations) radially outward. The third annular disc 173 is formed with a plurality of slits 201 (specifically, two locations) that extend from the openings 197 to the outer peripheral edge.

  The fourth annular disk 174 shown in FIG. 8 (e) has a non-circular through hole 205 formed in the center in the radial direction, and a plurality of (specifically, two) shafts around the through hole 205. It has a perforated disk shape with an opening 206 penetrating in the direction, and the outer diameter is the same as that of the first annular disk 171A and the like. The central through-hole 205 has a fitting portion 207 that is provided at a plurality of locations (specifically, three locations) in the circumferential direction and that fits the attachment shaft portion 39 in a substantially space-free state. Further, the through-hole 205 has a plurality of (specifically, three) notches 208 extending radially outward from between the fitting portions 207 adjacent to each other in the circumferential direction. The openings 206 each have a sector shape, and are aligned in the circumferential direction of the fourth annular disk 174 with the radial position of the fourth annular disk 174 aligned.

  The fifth annular disk 175A shown in FIG. 2 has a perforated disk shape in which a circular through hole 216A for fitting the mounting shaft portion 39 in a substantially space-free state is formed at the center in the radial direction. The outer diameter is the same as that of the first annular disk 171A or the like.

  The sixth annular disk 175B is a common part having the same shape as the fifth annular disk 175A. As with the fifth annular disk 175A, the sixth annular disk 175B has a through hole 216B formed in the center in the radial direction.

  It should be noted that a plurality of, specifically, six annular disks 171A, 171B, 173, 174, 175A, and 175B, which are deformed when flowing the oil liquid into the chamber 17 through the working fluid flow path 53, are discs. A valve 43 is configured. The annular discs 171A, 171B, 173, 174, 175A, and 175B constituting the disc valve 43 are laminated on the inner sheet 63 and directly on the outer sheet 64 via the spacer 170.

  Then, the spacer 170, the first annular disk 171A, the second annular disk 171B, the third annular disk 173, the fourth annular disk 174, the fifth annular disk 175A, and the sixth annular disk 175B are provided with the mounting shaft portion 39 provided inside. The spacer 77, the regulating member 78, and the fixing member 79 are sequentially laminated on the piston valve body 50 in this order to form the laminated portion 44.

  Hereinafter, the set state of the spacer 170 and the plurality of annular disks 171A, 171B, 173, 174, 175A, 175B will be described. In the following description, the radial direction of the spacer 170 and the annular disks 171A, 171B, 173, 174, 175A, 175B is the disk radial direction, the axial direction is the disk axial direction, and the circumferential direction is the disk circumferential direction.

  In the spacer 170 shown in FIG. 8A, the notch 186 is aligned with the notch 194A of the first annular disc 171A in the disc radial direction. The inner concave portion 187 of the spacer 170 is covered with the inner sheet 63 shown in FIG. 7 in the disk radial direction inner portion of the narrow portion 188 on one side in the disk axial direction, and the entire other side in the disk axial direction is the first annular disk 171A. Covered with. A portion surrounded by the inner concave portion 187 shown in FIG. 8A of the spacer 170 and the inner sheet 63 and the first annular disc 171A shown in FIG. 7 on both sides thereof is an introduction orifice 223, and the inner concave portion 187 is formed. The portion surrounded by the narrow portion 188, the inner sheet 63, and the first annular disk 171A is the minimum flow path area portion of the introduction orifice 223. In the introduction orifice 223, the disk radial direction outer side portion and the wide portion 189 of the narrow portion 188 of the spacer 170 shown in FIG. 8A face the chamber 121 shown in FIG. The chamber 121 is partially open. In addition, as shown in FIG. 9A, three inner concave portions 187 are formed in each of the notches 186 in the spacer 170, or two inner concave portions 187 are formed in two locations as shown in FIG. 9B. 9 or by forming inner concave portions 187 one by one as shown in FIG. 9C, the flow area of the introduction orifice 223 can be changed.

  The gap between the notch 186 of the spacer 170 and the mounting shaft 39 shown in FIG. 8A communicates with the gap between the notch 194A of the first annular disk 171A and the mounting shaft 39 shown in FIG. 8B. At the same time, it communicates with the gap between the notch 194B of the second annular disk 171B and the mounting shaft 39 shown in FIG. 8C, and the notch 199 and the mounting shaft of the third annular disk 173 shown in FIG. 8D. 39, and further communicated with the gap between the cutout portion 208 of the fourth annular disk 174 and the mounting shaft portion 39 shown in FIG. These gaps serve as an intermediate chamber 225 shown in FIG. In this intermediate chamber 225, the narrow portion 188 of the inner concave portion 187 of the spacer 170 shown in FIG. 8 (a) faces, so that the side opposite to the chamber 121 of the introduction orifice 223 shown in FIG. Yes. The intermediate chamber 225 is entirely covered with the inner sheet 63 on one side in the disk axial direction, and is covered with the fifth annular disk 175A on the other side in the disk axial direction. That is, the intermediate chamber 225 is notched on the inner peripheral side of the spacer 170 and the annular disks 171A, 171B, 173, 174 which are a part of the plurality of annular disks 171A, 171B, 173, 174, 175A, 175B. The inlet orifices 223 are formed between the intermediate chamber 225 and the opening 61 of the working fluid flow channel 53.

  The first annular disk 171 </ b> A is in contact with the outer seat 64 and forms a chamber 121 between the piston valve body 50 and the spacer 170. In a state where the first annular disk 171A is in contact with the outer sheet 64, the communication of the chamber 121, that is, the working fluid flow path 53, to the chamber 17 through the gap between the first annular disk 171A and the outer sheet 64 is restricted. . By changing the thickness of the spacer 170, the amount of bending of the first annular disk 171A in the set state on the outer sheet 64 changes, and the set load changes.

  The inner concave portion 200 of the third annular disk 173 shown in FIG. 8D faces the intermediate chamber 225 shown in FIG. The inside of the inner concave portion 200 shown in FIG. 8D is an intermediate passage 227 that opens to the intermediate chamber 225 shown in FIG. 7, and this intermediate passage 227 opens to the intermediate chamber 225. The intermediate passage 227 is entirely covered on the one side in the disk axial direction with the second annular disk 171B, and the inner part in the disk radial direction on the other side in the disk axial direction is covered with the fourth annular disk 174. The inner concave portion 200 shown in FIG. 8D of the third annular disk 173 has an outer portion in the disk radial direction facing the opening 206 of the fourth annular disk 174 shown in FIG.

  The inside of the opening 206 of the fourth annular disk 174 is a back pressure chamber 229 shown in FIG. 7, and therefore the intermediate passage 227 is formed on the inner concave part 200 of the third annular disk 173 shown in FIG. 7 is opened to the back pressure chamber 229 shown in FIG. 7 to allow the back pressure chamber 229 and the intermediate chamber 225 to communicate with each other. The back pressure chamber 229 has one side in the disk axial direction covered with the third annular disk 173 and the other side in the disk axial direction entirely covered with the fifth annular disk 175A. The back pressure chamber 229 is provided on the fourth annular disk 174 which is at least one of the plurality of annular disks 171A, 171B, 173, 174, 175A, 175B other than the annular disks 171A, 175B at both ends. The opening 206 shown in FIG.

  The opening 197 of the third annular disk 173 shown in FIG. 8D faces the opening 206 of the fourth annular disk 174 shown in FIG. 8E, and the entire one side in the disk axial direction is shown in FIG. It is covered with a second annular disk 171B shown in c). A portion surrounded by the slit 201 opened in the opening 197 shown in FIG. 8D, the second annular disc 171B shown in FIG. 8C, and the fourth annular disc 174 shown in FIG. A fixed orifice 231 shown in FIG. 7 is formed, and an opening 197 shown in FIG. 8D is a part of the back pressure chamber 229 shown in FIG. Therefore, the fixed orifice 231 opens to the back pressure chamber 229. The slit 201 shown in FIG. 8D of the fixed orifice 231 faces the chamber 17 shown in FIG. 7, and thus the fixed orifice 231 opens into the chamber 17. Here, the flow area of the fixed orifice 231 is set to be smaller than that of the introduction orifice 223.

  When the oil liquid flows from the working fluid flow path 53 to the chamber 17 through the chamber 121, the introduction orifice 223, the intermediate chamber 225, the intermediate passage 227, the back pressure chamber 229, and the fixed orifice 231 with respect to the above set state. When the flow rate is increased, the fifth annular disk 175A and the sixth annular disk 175B are deformed and separated from the fourth annular disk 174 and the third annular disk 173, which together formed the back pressure chamber 229 so far. Expand the road. The opening 206 of the fourth annular disc 174 shown in FIG. 8E, the third annular disc 173 shown in FIG. 8D covering one side in the disc axial direction, and the other side in the disc axial direction of the opening 206 are shown. The fifth annular disk 175A and the sixth annular disk 175B shown in FIG. 7 that are opened and closed form the first valve portion 233 whose flow path area changes. In the first valve portion 233, the pressure in the back pressure chamber 229 acts on the fifth annular disc 175A and the sixth annular disc 175B in the opening direction.

  Further, when the flow rate flowing through the working fluid channel 53 is further increased, the annular disks 171A, 171B, 173, 174, 175A, 175B are deformed and separated from the outer sheet 64, and the gap between the first annular disk 171A and the outer sheet 64 is increased. The oil liquid flows into the chamber 17 through. At that time, the annular disks 171A, 171B, 173, 174, 175A, and 175B change the flow path area of the gap between the first annular disk 171A and the outer sheet 64 according to the deformation amount. The annular discs 171A, 171B, 173, 174, 175A, 175B and the outer seat 64 form a second valve portion 234 whose flow area changes. In the second valve portion 234, the pressure in the back pressure chamber 229 acts on the first annular disc 171A and the second annular disc 171B in the closing direction, that is, in the direction of the outer seat 64.

  The above hydraulic circuit diagram of the shock absorber is the same as that of the first embodiment. In the second embodiment, the characteristics that can be tuned differ depending on the position of each orifice and the configuration of the annular disk. For example, in contrast to the first embodiment, by providing the fixed orifice 231 in the third annular disk 173, the fourth annular disk 174 having the back pressure chamber 229 is disposed on the opposite side of the third annular disk 173 with one first disk. A 5-ring disc 175A can also be used. This configuration is effective when it is desired to further lower the valve opening pressure at the valve opening point A. In the second embodiment, since the spacer 170 having the introduction orifice 223 also serves as a step adjustment, there is a limit when it is desired to increase the step, but in the case of the first embodiment, the first annular disk 171A is provided. Since it does not serve as a step adjustment, it can be made a specification with a large step.

  In the above embodiment, the case where the present invention is applied to the piston 18 having the piston valve body 50 has been described as an example. However, the present invention can also be applied to the base valve 23 having the base valve body 30. Furthermore, the present invention can also be applied to a damping force generation mechanism provided outside the cylinder 19.

  In the embodiment described above, a cylinder in which a working fluid is sealed, a piston that is slidably fitted in the cylinder, defines two chambers in the cylinder, and is connected to the piston. A piston rod extending to the outside of the cylinder; a valve body having a working fluid channel through which a working fluid flows by sliding of the piston in the cylinder; and an opening of the working fluid channel of the valve body A shaft portion protruding from the surface provided with the valve body, an inner seat provided around the shaft portion of the valve body, and an outer seat provided so as to surround the opening of the working fluid channel of the valve body A plurality of annular discs that penetrate the shaft portion and are stacked on the inner sheet and the outer sheet, and are provided on the shaft portion and the inner sheet. An intermediate chamber formed by providing a notch on the inner peripheral side of a part of the plurality of annular disks, and a working fluid flow A back pressure chamber comprising an introduction orifice formed between the opening of the passage and the intermediate chamber, an opening provided in at least one of the plurality of annular disks other than the annular disks at both ends, and the back An intermediate passage for communicating the pressure chamber and the intermediate chamber, and a fixed orifice provided on the downstream side of the back pressure chamber, wherein the flow area of the fixed orifice is smaller than the introduction orifice. . Thereby, a favorable damping force characteristic can be obtained.

11 Shock absorber 15 Piston rod 16, 17 chamber 18 Piston 19 Cylinder 39 Mounting shaft (shaft)
50 Piston valve body (Valve body)
52, 53 Working fluid channel 61 Opening part of working fluid channel 63 Inner sheet 64 Outer sheet 71A, 72, 71B, 74, 75, 76, 171A, 171B, 173, 174, 175A, 175B Annular disk 79 Fixing member 86A , 86B, 94, 108, 186, 194A, 194B, 199, 208 Notch portion 106, 206 Opening portion 123, 223 Introducing orifice 125, 225 Intermediate chamber 127, 227 Intermediate passage 129, 229 Back pressure chamber 131, 231 Fixed orifice

Claims (1)

A cylinder filled with a working fluid;
A piston slidably fitted in the cylinder and defining the inside of the cylinder in two chambers;
A piston rod connected to the piston and extending outside the cylinder;
A valve body having a working fluid flow path through which a working fluid flows by sliding of the piston in the cylinder;
A shaft portion projecting from the surface of the valve body where the opening of the working fluid flow path is provided;
An inner seat provided around the shaft portion of the valve body;
An outer seat provided so as to surround the opening of the working fluid channel of the valve body;
A plurality of annular disks that penetrate the shaft and are stacked on the inner sheet and the outer sheet;
A fixing member provided in the shaft portion and sandwiching the plurality of annular disks in the axial direction with the inner sheet;
A shock absorber with
An intermediate chamber formed by providing a cutout portion on the inner peripheral side in a part of the plurality of annular disks;
An introduction orifice formed between the opening of the working fluid flow path and the intermediate chamber;
A back pressure chamber comprising an opening provided in at least one of the plurality of annular disks other than the annular disks at both ends;
An intermediate passage communicating the back pressure chamber and the intermediate chamber;
A fixed orifice provided downstream of the back pressure chamber;
Consists of
A shock absorber characterized in that a flow area of the fixed orifice is smaller than that of the introduction orifice.

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