Buffer and suspension device

Abstract

To provide a technique capable of reducing an axial size of a rod.SOLUTION: A buffer includes: an adjustment valve 41 that is disposed on a first communication passage for communicating a first chamber Y1 and a second chamber Y2 and opens the first communication passage when second pressure that is pressure of the second chamber Y2 is higher than first pressure that is pressure of the first chamber Y1; a float valve 52 that is provided on the second communication passage formed around a rod 20 and communicating the first chamber Y1 and the second chamber Y2, that closes the second communication passage and is elastically deformed so as to increase volume of a pressure adjustment chamber 500 for generating back pressure relative to the adjustment valve 41 when the second pressure is higher than the first pressure and that opens the second communication passage when the first pressure is higher than the second pressure; a formation member 48 that forms the pressure adjustment chamber 500 together with the float valve 52; and a nut 49 that regulates the elastic deformation of the float valve 52. An inner peripheral part of the float valve 52 is sandwiched between the formation member 48 and the nut 49.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to shock absorbers and suspension systems. [Background technology]

[0002] For example, the pressure buffer device described in Patent Document 1 includes a rod inserted into a cylinder that contains liquid and movable axially relative to the cylinder, and a piston connected to the rod that divides the space within the cylinder into a first liquid chamber and a second liquid chamber that contain liquid. The pressure buffer device described in Patent Document 1 also includes a flow path forming portion that forms a flow path for liquid between the first liquid chamber and the second liquid chamber, a valve portion that opens and closes the flow path in the flow path forming portion to generate a damping force, and a damping force changing portion that has an inflow portion into which liquid flows and changes the damping force generated by the valve portion depending on the pressure of the liquid in the inflow portion. The damping force changing portion also includes a pressure changing portion that changes the pressure of the liquid in the inflow portion by deforming or displacing, a support portion that supports the pressure changing portion, and an inflow forming portion that holds the support portion with a crimped portion and forms the inflow portion together with the support portion. The damping force changing portion also has a filter that is provided on the liquid flow path to the inlet portion and that collects foreign matter that gets mixed into the liquid, and also has a filter portion that is held in the inlet forming portion together with the support portion by the crimping portion. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6539009 Summary of the Invention [Problem to be solved by the invention]

[0004] The device described in Patent Document 1 has room for improvement in terms of reducing the axial size of the rod. An object of the present invention is to provide a shock absorber or the like that can reduce the axial size of the rod. [Means for solving the problem]

[0005] The present invention, which was completed with the above object in mind, is a shock absorber comprising: a first valve portion disposed in a first communication passage communicating a first chamber and a second chamber partitioned by a piston held in a rod, the first valve portion opening the first communication passage when a second pressure, which is the pressure in the second chamber, is higher than a first pressure, which is the pressure in the first chamber, and closing the first communication passage when the first pressure is higher than the second pressure; a second valve portion formed around the rod and provided in a second communication passage communicating the first chamber and the second chamber, the second valve portion closing the second communication passage when the second pressure is higher than the first pressure, elastically deforming to increase the volume of a back pressure chamber that generates back pressure against the first valve portion, and opening the second communication passage when the first pressure is higher than the second pressure; a forming member which forms the back pressure chamber together with the second valve portion; and a restricting member which restricts the elastic deformation of the second valve portion, wherein the inner or outer peripheral portion of the second valve portion is sandwiched between the forming member and the restricting member. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a shock absorber or the like that can reduce the axial size of the rod. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a diagram showing an example of a schematic configuration of a suspension device according to a first embodiment. [Figure 2] 3 is a diagram showing an example of a cross section of a piston portion and a damping force change portion according to the first embodiment. FIG. [Figure 3] FIG. 2 is a diagram illustrating an example of a schematic configuration of a diaphragm member. [Figure 4] FIG. 2 is a diagram illustrating an example of a schematic configuration of a support spring. [Figure 5] 4 is a diagram showing an example of a partial cross section of a damping force changing portion; FIG. [Figure 6] 5A to 5C are explanatory diagrams illustrating the operation of the piston portion and the bottom portion during the compression stroke and the extension stroke. [Figure 7] 10A and 10B are diagrams illustrating an example of the operation of the damping force change unit during an extension stroke. [Figure 8] 10A and 10B are diagrams illustrating an example of the operation of the damping force changing unit during a compression stroke. [Figure 9] FIG. 10 is a diagram illustrating an example of the operation of a float valve. [Figure 10] FIG. 10 is a diagram showing an example of a nut according to a modified example. [Figure 11] FIG. 10 is a diagram showing an example of a cross section of a shock absorber according to a second embodiment. [Figure 12] 10A and 10B are diagrams illustrating an example of the operation of the float valve according to the second embodiment. [Figure 13] 10A and 10B are diagrams illustrating an example of an end cap according to a modified example. [Figure 14] FIG. 10 is a diagram showing an example of a cross section of a shock absorber according to a third embodiment. [Figure 15] 10A and 10B are diagrams illustrating an example of the operation of the float valve according to the third embodiment. [Figure 16] 10A and 10B are diagrams illustrating an example of an end cap according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First Embodiment FIG. 1 is a diagram showing an example of a schematic configuration of a suspension system 1 according to the first embodiment. The suspension system 1 is a suspension used in four-wheeled vehicles such as passenger cars, and as shown in Fig. 1, comprises a hydraulic shock absorber 2 and a coil spring 3 arranged on the outside of the shock absorber 2. The suspension system 1 also comprises a lower spring seat 4 that supports an end of the coil spring 3 on a first axial side (lower side in Fig. 1) of a rod 20 described below, and an upper spring seat 5 that supports an end of the coil spring 3 on a second axial side (upper side in Fig. 1) of the rod 20.

[0009] The suspension device 1 also includes a vehicle body side bracket 6 for attaching the suspension device 1 to a vehicle, a wheel side bracket 7 for attaching the suspension device 1 to a wheel, and a dust cover 8 that covers at least a portion of the cylinder portion 10 and the rod 20. Hereinafter, the axial direction of the rod 20 may be simply referred to as the "axial direction." Furthermore, the first axial side (lower side in FIG. 1) and the second axial side (upper side in FIG. 1) may be simply referred to as the "first side" and the "second side," respectively. Furthermore, the direction intersecting the axial direction (for example, the perpendicular direction) may be simply referred to as the "radial direction." In the radial direction, the side of the center line of the cylinder 11 may be simply referred to as the "inner side," and the side away from the center line may be simply referred to as the "outer side."

[0010] The shock absorber 2 will be described in detail below. The shock absorber 2 includes a cylinder portion 10 that stores oil, and a rod 20 whose second end protrudes from the cylinder portion 10 and whose first end is inserted into the cylinder portion 10. The shock absorber 2 also includes a piston portion 30 that is provided at the first end of the rod 20, a damping force changing portion 40 that adjusts the damping force generated by the piston portion 30, and a bottom portion 60 that is provided at the first end of the cylinder portion 10.

[0011] [Cylinder part 10] The cylinder section 10 includes a thin-walled cylindrical cylinder 11, a thin-walled cylindrical outer cylinder 12 provided on the outside of the cylinder 11, and a bottom cover 13 that closes a first end of the outer cylinder 12. The cylinder 11 and the outer cylinder 12 are arranged so that the center line direction of the cylinder coincides with the axial direction. The cylinder section 10 forms a reservoir chamber R between the outer peripheral surface of the cylinder 11 and the inner peripheral surface of the outer cylinder 12. The reservoir chamber R is filled with oil on the first side and gas on the second side.

[0012] The cylinder portion 10 also includes a rod guide 14 that movably supports the rod 20, a bump stopper cap 15 attached to the second end of the outer tube 12, and a sealing member 16 that prevents oil from leaking from within the cylinder portion 10 and prevents foreign matter from entering the cylinder portion 10.

[0013] [Rod 20] The rod 20 is a solid or hollow rod-shaped member. The rod 20 has a first-side mounting portion 21 provided on a first side, a second-side mounting portion 22 provided on a second side, and a shaft portion 23 between the first-side mounting portion 21 and the second-side mounting portion 22. The first-side mounting portion 21 and the second-side mounting portion 22 each have a spiral groove cut into their outer surface and function as a bolt. The first-side mounting portion 21 holds the piston portion 30 and the damping force changer 40. The second-side mounting portion 22 holds a vehicle body side bracket 6, which is connected to, for example, the vehicle body.

[0014] 2, the rod 20 has a bypass passage 25 that allows oil to circulate between the second chamber Y2 and the first chamber Y1, bypassing the piston portion 30. The bypass passage 25 is composed of a groove extending in the radial direction formed at the end of the first side of the shaft portion 23, and a groove extending in the axial direction formed on the second side of the spiral groove in the first side mounting portion 21.

[0015] [Bottom part 60] As shown in FIG. 1, the bottom portion 60 includes a valve body 61 having a plurality of oil passages passing through in the axial direction, a valve 62 provided on a first side of the valve body 61, and a valve 63 provided on a second side of the valve body 61. The valve body 61 of the bottom portion 60 separates the first chamber Y1 and the reservoir chamber R.

[0016] [Piston part 30] FIG. 2 is a diagram showing an example of a cross section of the piston portion 30 and the damping force change portion 40 according to the first embodiment. FIG. 3 is a diagram showing an example of a schematic configuration of the diaphragm member 42. As shown in FIG. FIG. 4 is a diagram showing an example of a schematic configuration of the support spring 46. As shown in FIG. FIG. 5 is a diagram showing an example of a partial cross section of the damping force changer 40. As shown in FIG.

[0017] 2, the piston portion 30 includes a piston 31, an extension side damping valve portion 321 provided on a first side of the piston 31, and a compression side damping valve portion 322 provided on a second side of the piston 31. The piston portion 30 also includes a first valve stopper 350 and a second valve stopper 353.

[0018] Piston 31 has a columnar portion 311 formed in a substantially cylindrical shape and having a plurality of oil passages, which will be described later, formed therein, and a cylindrical portion 312 provided on a first side of columnar portion 311. The piston 31 contacts the cylinder 11 via a sliding portion provided on the radially outer side to reduce frictional resistance. The piston portion 30 divides the space in the cylinder 11 filled with oil into a first chamber Y1 on the first side and a second chamber Y2 on the second side.

[0019] Furthermore, the piston 31 has a mounting hole 33R through which the rod 20 passes, and an extension-side oil passage 341 and a compression-side oil passage 342 formed radially outward from the mounting hole 33R. A plurality of extension-side oil passages 341 and a plurality of compression-side oil passages 342 are provided at approximately equal intervals in the circumferential direction. The extension-side oil passage 341 and the compression-side oil passage 342 each enable oil to flow between the first chamber Y1 and the second chamber Y2.

[0020] The extension side damping valve portion 321 can be configured by a plurality of elastic, substantially disk-shaped plates. The extension side damping valve portion 321 always opens the first side of the compression side oil passage 342, and opens and closes the first side of the extension side oil passage 341. The compression side damping valve portion 322 can be configured by a plurality of elastic, substantially disk-shaped plates. The compression side damping valve portion 322 always opens the second side of the extension side oil passage 341, and opens and closes the second side of the compression side oil passage 342.

[0021] The first valve stopper 350 has a mounting hole 350R through which the rod 20 passes. The second valve stopper 353 has a first outer diameter portion 353a having a predetermined outer diameter and a second outer diameter portion 353b having an outer diameter larger than that of the first outer diameter portion 353a. The second valve stopper 353 is provided so that the first outer diameter portion 353a fits inside the cylindrical portion 312 of the piston 31. When the extension side damping valve portion 321 deforms, the second valve stopper 353 prevents the extension side damping valve portion 321 from deforming more than a certain amount. The second valve stopper 353 also functions as a valve seat for the adjustment valve 41, which will be described later.

[0022] The second valve stopper 353 also has an attachment hole 353R that extends in the axial direction and has an inner diameter that allows the first-side attachment portion 21 of the rod 20 to pass through. The second valve stopper 353 also has a recess 353c that opens toward the adjustment valve 41, which will be described later. The first side mounting portion 21 of the second valve stopper 353 is fitted into the mounting hole 353R, and the extension side damping valve portion 321 is sandwiched between the first side mounting portion 21 and the piston 31. The recess 353c of the second valve stopper 353 is a space that communicates with the bypass passage 25.

[0023] [Damping force change unit 40] 2, the damping force changer 40 includes an adjustment valve 41 that controls the flow of oil in the bypass path 25, a throttle member 42 that throttles the flow of oil in the bypass path 25, and a forming member 48 that sandwiches the adjustment valve 41 and the throttle member 42 between itself and the second valve stopper 353 and forms a pressure adjustment chamber 500. The damping force changer 40 also includes a spool 44 that is movably provided with respect to the forming member 48, an O-ring 45 that seals the gap between the forming member 48 and the spool 44, and a support spring 46 that applies a spring force to the spool 44. The damping force changer 40 also includes a float valve 52 that forms the pressure adjustment chamber 500 together with the forming member 48, and a nut 49 that is tightened to the first-side mounting portion 21 of the rod 20.

[0024] The adjusting valve 41 covers the recessed portion 353c of the second valve stopper 353. When the adjusting valve 41 is deformed and no longer covers the recessed portion 353c, the adjusting valve 41 opens the recessed portion 353c and allows the oil in the second chamber Y2 to flow to the first chamber Y1 side through the bypass path 25 and the recessed portion 353c.

[0025] As shown in Fig. 3, the throttle member 42 is elastic and has an annular shape. The throttle member 42 has an opening 42H on the radially inner side through which the first-side mounting portion 21 of the rod 20 passes, and an orifice 42S cut out from the opening 42H toward the outside. The throttle member 42, together with the adjustment valve 41, is provided between the second valve stopper 353 and the forming member 48. As shown in Fig. 5, the orifice 42S extends to a pressure chamber 47, which will be described later. The orifice 42S is also connected to the first end of the bypass path 25. In this embodiment, two orifices 42S are provided in the circumferential direction, but the number, length, slit width, etc. can be set as appropriate.

[0026] The forming member 48 has a columnar portion 481 and an annular protruding portion 482 provided on a second side of the columnar portion 481. A through hole 48R is formed in the center of the columnar portion 481, through which the first-side mounting portion 21 of the extension rod 20 passes in the axial direction, and a communication passage 48H is formed outside the through hole 48R, penetrating in the axial direction. The communication passage 48H connects a pressure chamber 47 and a pressure adjustment chamber 500, which will be described later, and forms an oil flow path between the pressure chamber 47 and the pressure adjustment chamber 500. In this embodiment, a plurality of communication passages 48H are provided in the circumferential direction of the forming member 48.

[0027] Further, forming member 48 is formed with recess 484 recessed from the end face on the first side to the second side. Recess 484 is cylindrical. Float valve 52 is provided to cover the opening of recess 484, and recess 484 and float valve 52 form pressure adjustment chamber 500. The portion of the end face on the first side of the forming member 48 that is outside the recess 484 protrudes more toward the first side than the portion that is inside the recess 484.

[0028] The spool 44 has a generally cylindrical shape. The second side of the spool 44 protrudes radially inward, and the columnar portion 481 of the forming member 48 is inserted into the first side. The spool 44 is formed so as to be able to come into contact with the adjusting valve 41 on the second side, and is biased on the first side by a support spring 46. The spool 44 applies a force to the adjusting valve 41 to press the adjusting valve 41 against the end of the second valve stopper 353 on the first side. The spool 44 also forms a pressure chamber 47 together with a forming member 48 and the adjusting valve 41 .

[0029] The O-ring 45 is attached to a forming member 48 and supports the spool 44 so that it can move in the axial direction. As shown in Fig. 4, the support spring 46 is formed in a ring shape and has a plurality of protrusions 46a that protrude outward from the outer periphery. The inner periphery of the support spring 46 is supported by the annular protrusion 482 of the forming member 48. As shown in Fig. 5, the support spring 46 biases the spool 44 toward the second side.

[0030] The nut 49 has, in its central portion, a bolt hole 49R formed with an internal thread that is fastened to the external thread formed on the first-side mounting portion 21 of the rod 20. The nut 49 is formed so that its outer diameter is smaller than the diameter of the outer peripheral surface of the recess 484 of the forming member 48. The nut 49 has a central portion 491 which is an end face on the second side and sandwiches the float valve 52 between itself and the forming member 48. The nut 49 also has a recess 492 formed on the outer side of the central portion 491, the recess 492 being recessed from the central portion 491. The outer diameter of the central portion 491 is larger than the diameter of the inner circumferential surface of the recess 484 of the forming member 48 . When the float valve 52 is flexibly deformed, the recess 492 allows the float valve 52 to deform by a certain amount, and restricts deformation beyond the certain amount.

[0031] The float valve 52 has a main body 56 formed into an annular shape from a thin metal plate, and a rubber part 57 provided on the outer periphery of the main body 56 and formed from rubber. The inner diameter of the main body 56 is larger than the outer diameter of the rod 20 and smaller than the diameter of the inner circumferential surface of the recess 484 of the forming member 48. The float valve 52 is supported by the forming member 48 and the nut 49 by sandwiching the inner circumferential portion of the main body 56 between a portion of the first end face of the forming member 48 that is inside the recess 484 and a central portion 491 of the nut 49.

[0032] The outer diameter of the main body 56 is smaller than the diameter of the outer peripheral surface of the recess 484 of the forming member 48. The main body 56 is a thin, plate-like member that is easily elastically deformed. Therefore, when the main body 56 receives pressure from the pressure adjustment chamber 500, it can deform until it comes into contact with the recess 492 of the nut 49.

[0033] The rubber part 57 has an annular base end part 571 baked onto the outer periphery of the main body part 56, and a protruding part 572 that protrudes cylindrically from the outer periphery of the base end part 571 to the second side. The diameter of the outer periphery of the protruding part 572 is equal to or greater than the diameter of the outer periphery of the recessed part 484 of the forming member 48. The thickness of the rubber portion 57 can be set as appropriate. When the pressure in the pressure adjustment chamber 500 is higher than the pressure in the first chamber Y1, the protruding portion 572 of the rubber portion 57 comes into contact with the outer peripheral surface of the recessed portion 484 of the forming member 48, sealing the pressure adjustment chamber 500. On the other hand, when the pressure in the first chamber Y1 is higher than the pressure in the pressure adjustment chamber 500, the protruding portion 572 moves away from the outer peripheral surface of the recessed portion 484 of the forming member 48, allowing oil to flow from the first chamber Y1 to the pressure adjustment chamber 500.

[0034] The float valve 52 configured as described above deforms or displaces during the extension stroke or compression stroke, thereby changing the volume of the pressure adjustment chamber 500. Also, by closing or opening the opening of the recess 484 of the forming member 48, the float valve 52 blocks or allows the flow of oil between the pressure adjustment chamber 500 and the first chamber Y1 side.

[0035] Next, the operation of the shock absorber 2 will be described. FIG. 6 is a diagram illustrating the operation of the piston portion 30 and the bottom portion 60 during the compression stroke and the extension stroke.

[0036] 6, during the compression stroke in which the rod 20 moves toward the first side relative to the cylinder 11 as indicated by the white arrow, the oil pressure in the first chamber Y1 rises. This causes the compression side damping valve portion 322, which blocks the compression side oil passage 342, to open, and oil flows into the second chamber Y2 through the compression side oil passage 342 as indicated by arrow A. This flow of oil from the first chamber Y1 to the second chamber Y2 is throttled by the compression side damping valve portion 322, and the damping force during the compression stroke of the shock absorber 2 is obtained. Furthermore, the oil in the first chamber Y1, whose pressure has increased due to the axial movement of the piston 31 toward the first side, opens the valve 62 in the bottom portion 60. Then, the oil in the first chamber Y1 flows out into the reservoir chamber R, as shown by arrow B.

[0037] 6, during the extension stroke in which the rod 20 moves toward the second side relative to the cylinder 11 as indicated by the white arrow, the first chamber Y1 becomes short of oil by that volume, resulting in negative pressure. As a result, the oil in the second chamber Y2 passes through the extension-side oil passage 341 of the piston portion 30, opens the extension-side damping valve portion 321 that closes this extension-side oil passage 341, and flows into the first chamber Y1 as indicated by arrow C. The flow of oil from the second chamber Y2 to the first chamber Y1 is throttled by the extension-side damping valve portion 321 of the piston portion 30, and the damping force during the extension stroke of the shock absorber 2 is obtained. Furthermore, when the piston 31 moves to the second side, the oil in the reservoir chamber R opens the valve 63 as shown by the arrow D and flows into the first chamber Y1.

[0038] FIG. 7 is a diagram showing an example of the operation of the damping force changing unit 40 during the extension stroke. When the rod 20 moves with a small amplitude, oil that flows from the second chamber Y2 into the bypass passage 25 during the extension stroke passes through the orifice 42S of the throttle member 42 and the communication passage 48H of the forming member 48 and flows into the pressure adjustment chamber 500. At this time, the main body 56 of the float valve 52 bends toward the recess 492 of the nut 49, increasing the volume of oil that can be accommodated in the pressure adjustment chamber 500. This makes it difficult for the oil pressure in the pressure adjustment chamber 500 to increase. Therefore, the force exerted by the spool 44 on the pressure adjustment chamber 500 side to push the adjustment valve 41 toward the second valve stopper 353 also decreases. The adjustment valve 41 then opens the recess 353c of the second valve stopper 353. The oil flowing through the bypass passage 25 flows from the recess 353c of the second valve stopper 353 into the first chamber Y1. Thus, when the rod 20 moves with a small amplitude, oil flows around the piston 30. Therefore, when the rod 20 moves with a small amplitude, during the extension stroke, in addition to the oil flow in the extension-side oil passage 341 of the piston portion 30 (see Figure 6), oil also flows through the bypass passage 25, and the damping force generated in the piston portion 30 becomes smaller.

[0039] On the other hand, when the rod 20 moves with a large amplitude, during the extension stroke, the oil that has flowed from the second chamber Y2 into the bypass passage 25 passes through the orifice 42S of the throttle member 42 and the communication passage 48H of the forming member 48 and flows into the pressure adjustment chamber 500. When the rod 20 moves with a large amplitude, the main body 56 of the float valve 52 immediately bends to the recess 492 of the nut 49 in the pressure adjustment chamber 500, and the contact pressure of the rubber part 57 with the outer peripheral surface of the recess 484 of the forming member 48 increases, causing the oil in the pressure adjustment chamber 500 to become pressurized. Therefore, the force of the spool 44 provided on the pressure adjustment chamber 500 side pressing the adjustment valve 41 toward the second valve stopper 353 increases. Then, the adjustment valve 41 blocks the recess 353c of the second valve stopper 353. Therefore, when the rod 20 moves with a large amplitude, oil does not flow through the bypass path 25 during the extension stroke, and only oil flows through the extension-side oil path 341 of the piston portion 30 (see Figure 6), so the damping force generated in the piston portion 30 becomes large.

[0040] FIG. 8 is a diagram showing an example of the operation of the damping force changing section 40 during the compression stroke. On the other hand, during the compression stroke, the pressure in the first chamber Y1 becomes higher than the pressure in the pressure adjustment chamber 500. Then, oil that passes through the gap between the outer circumferential surface of the recess 484 of the forming member 48 and the outer circumferential part of the nut 49 bends the outer circumferential part toward the second side, starting from the inner circumferential part of the main body part 56 of the float valve 52. As a result, the protruding part 572 of the rubber part 57 of the float valve 52 moves away from the outer circumferential surface of the recess 484 of the forming member 48, and oil flows from the first chamber Y1 into the pressure adjustment chamber 500.

[0041] As described above, when the rod 20 moves slightly, for example, when the vehicle is traveling on a rough road, the shock absorber 2 reduces the damping force, thereby improving the ride comfort of the vehicle. On the other hand, when the rod 20 moves significantly, for example, when the vehicle is traveling around a curve, the shock absorber 2 increases the damping force, thereby improving the handling stability of the vehicle.

[0042] Next, the operation of the float valve 52 will be described in detail. FIG. 9 is a diagram illustrating an example of the operation of the float valve 52. As described above, during the extension stroke, the pressure in the pressure adjustment chamber 500 becomes higher than the pressure in the first chamber Y1, so the protruding portion 572 of the rubber portion 57 of the float valve 52 sticks to the outer peripheral surface of the recessed portion 484 of the forming member 48, sealing the pressure adjustment chamber 500. Even if a foreign object is present between the protruding portion 572 of the rubber portion 57 of the float valve 52 and the outer peripheral surface of the recessed portion 484 of the forming member 48, as shown in Figure 9, the rubber portion 57 deforms to encase the foreign object, so the sealability of the pressure adjustment chamber 500 is maintained.

[0043] On the other hand, during the compression stroke, the pressure in the first chamber Y1 becomes higher than the pressure in the pressure adjustment chamber 500, and when oil flows from the first chamber Y1 into the pressure adjustment chamber 500 as shown in Figure 8, the protrusion 572 of the rubber part 57 of the float valve 52 moves away from the outer peripheral surface of the recess 484 of the forming member 48, allowing oil to flow from the outside of the main body part 56 into the pressure adjustment chamber 500.

[0044] Therefore, even if foreign matter is present between the protruding portion 572 of the rubber portion 57 of the float valve 52 and the outer peripheral surface of the recessed portion 484 of the forming member 48, the foreign matter is also carried into the pressure adjustment chamber 500 by the oil flowing from the first chamber Y1 to the pressure adjustment chamber 500. As a result, foreign matter is unlikely to be present between the protruding portion 572 of the rubber portion 57 of the float valve 52 and the recessed portion 484 of the forming member 48, so that the sealing of the pressure adjustment chamber 500 is maintained with high reliability.

[0045] As described above, the shock absorber 2 includes the adjustment valve 41 (an example of a first valve section) that is disposed on the first communication passage (e.g., the bypass passage 25 and the recess 353c) that communicates between the first chamber Y1 and the second chamber Y2 defined by the piston 31, and that opens the first communication passage when the second pressure, which is the pressure in the second chamber Y2, is higher than the first pressure, which is the pressure in the first chamber Y1, and closes the first communication passage when the first pressure is higher than the second pressure. The shock absorber 2 also includes the float valve 52 (an example of a second valve section) that is disposed on the second communication passage (e.g., the pressure chamber 47, the communication passage 48H, the pressure adjustment chamber 500) that is formed around the rod 20 and communicates between the first chamber Y1 and the second chamber Y2, and that closes the second communication passage when the second pressure is higher than the first pressure, elastically deforms to increase the volume of the pressure adjustment chamber 500 (an example of a back pressure chamber) that generates back pressure against the adjustment valve 41, and that opens the second communication passage when the first pressure is higher than the second pressure. The shock absorber 2 also includes a forming member 48 that forms a pressure adjustment chamber 500 together with the float valve 52, and a nut 49 (an example of a regulating member) that regulates the elastic deformation of the float valve 52, and the inner periphery of the float valve 52 is sandwiched between the forming member 48 and the nut 49.

[0046] According to the shock absorber 2 configured as described above, the inner peripheral portion of the float valve 52 is sandwiched between the forming member 48 and the nut 49, so there is no need to provide a member (such as a leaf spring) that applies force to the float valve 52 to suppress axial movement of the float valve 52. As a result, the axial size of the shock absorber 2 can be reduced.

[0047] The nut 49 is formed with a female thread that is fastened to the male thread formed on the rod 20, and the inner periphery of the float valve 52 is sandwiched between the forming member 48 and the nut 49, and the float valve 52 is held in place by the axial force that is generated when the nut 49 is fastened to the rod 20. This makes it possible to firmly hold the inner periphery of the float valve 52.

[0048] The float valve 52 also has a metal main body 56 and a rubber part 57 molded from rubber attached to the main body 56. When the second pressure is higher than the first pressure, the rubber part 57 comes into contact with the forming member 48 to seal the pressure adjustment chamber 500, and when the first pressure is higher than the second pressure, the rubber part 57 separates from the forming member 48 to allow oil (an example of a liquid) flowing from the first chamber Y1 to move into the pressure adjustment chamber 500. The float valve 52 allows the pressure adjustment chamber 500 to be sealed and opened with a simple configuration.

[0049] (Modification of nut 49) FIG. 10 is a diagram showing an example of a nut 249 according to a modified example. In the shock absorber 2 described above, the nut 49 may have the configuration of a nut 249 according to a modified example shown in FIG. The nut 249 differs from the nut 49 in that an axial through hole 249H is formed therein. For example, a plurality of through holes 249H may be provided circumferentially around the bolt hole 49R. For example, the radial position of the through hole 249H may be the same as the radial position of the recess 484 of the forming member 48. By forming the through hole 249H in the nut 249, when the pressure in the first chamber Y1 becomes higher than the pressure in the pressure adjustment chamber 500 during the compression stroke, oil flows from the first chamber Y1 into the pressure adjustment chamber 500 through the through hole 249H. The outer diameter of the nut 249 may be larger than the diameter of the outer peripheral surface of the recess 484 of the forming member 48. For example, the outer diameter of the nut 249 may be larger than the outer diameter of the spool 44.

[0050] Second Embodiment FIG. 11 is a diagram showing an example of a cross section of a shock absorber 202 according to the second embodiment. FIG. 12 is a diagram illustrating an example of the operation of the float valve 252 according to the second embodiment. A shock absorber 202 according to the second embodiment differs from the shock absorber 2 according to the first embodiment in that a piston nut 43 and an end cap 51 are provided instead of the forming member 48 and the nut 49. The shock absorber 202 also differs from the shock absorber 2 in that a float valve 252 corresponding to the float valve 52 has a rubber part 257 on the inner periphery of a main body part 256, and the outer periphery of the float valve 252 is sandwiched between the piston nut 43 and the end cap 51. Differences from the first embodiment will be described below. The same components in the first and second embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

[0051] The piston nut 43 sandwiches the adjustment valve 41 and the throttle member 42 between itself and the second valve stopper 353 , and forms a pressure adjustment chamber 502 corresponding to the pressure adjustment chamber 500 . The piston nut 43 has a columnar portion 431 , an annular protruding portion 432 provided on the second side of the columnar portion 431 , and a cylindrical portion 433 provided on the first side of the columnar portion 431 .

[0052] The columnar portion 431 is formed with a communication passage 43H and a recess 434, which correspond to the communication passage 48H and the recess 484 according to the first embodiment. The columnar portion 431 is also formed with a bolt hole 43R, which is a through-hole into which the first-side mounting portion 21 of the extension rod 20 is fitted in the axial direction. The piston nut 43 is fixed to the rod 20 by tightening a female thread formed in the bolt hole 43R onto a male thread formed on the outer peripheral surface of the first-side mounting portion 21 of the rod 20. The piston nut 43 of this embodiment holds the various members that make up the damping force changer 40 and the piston portion 30 to the rod 20. The cylindrical portion 433 has a crimped portion 43K at the end on the first side. The crimped portion 43K is formed by plastically deforming the end of the cylindrical portion 433, which was formed in a straight shape, by roll crimping.

[0053] The end cap 51 is an annular member provided on the first side of the cylindrical portion 431 of the piston nut 43, and covers the opening of the recess 434 formed in the cylindrical portion 431. However, the inner diameter of the end cap 51 is formed larger than the diameter of the inner circumferential surface of the recess 434 of the piston nut 43, and a gap is formed between the inner circumferential portion of the end cap 51 and the inner circumferential portion of the recess 434 of the piston nut 43.

[0054] On the other hand, the outer diameter of the end cap 51 is larger than the diameter of the outer peripheral surface of the recess 434 of the piston nut 43 and smaller than the inner diameter of the cylindrical portion 433 of the piston nut 43. The end cap 51 is held inside the cylindrical portion 433 of the piston nut 43 by the crimped portion 43K of the piston nut 43.

[0055] The end cap 51 has an outer circumferential portion 511 that sandwiches the float valve 252 between itself and the piston nut 43. The end cap 51 also has a recess 512 formed inside the outer circumferential portion 511, recessed from the end face of the outer circumferential portion 511 on the second side. The inner diameter of the outer circumferential portion 511 is smaller than the diameter of the outer circumferential surface of the recess 434 of the piston nut 43. When the float valve 252 is flexibly deformed, the recess 512 allows the float valve 252 to deform by a certain amount, and restricts deformation beyond the certain amount.

[0056] The float valve 252 has a main body portion 256 corresponding to the main body portion 56 and a rubber portion 257 corresponding to the rubber portion 57 . The outer diameter of the main body 256 is larger than the diameter of the outer peripheral surface of the recess 434 of the piston nut 43 and smaller than the inner diameter of the cylindrical portion 433 of the piston nut 43. The float valve 252 is supported by the piston nut 43 and the end cap 51 by sandwiching the outer peripheral portion of the main body 256 between a portion of the first end face of the cylindrical portion 431 of the piston nut 43 that is outside the recess 434 and the outer peripheral portion 511 of the end cap 51.

[0057] The inner diameter of the main body 256 is larger than the diameter of the inner circumferential surface of the recess 434 of the piston nut 43. The main body 256 is a thin, plate-like member that is easily elastically deformed. Therefore, when subjected to the pressure of the pressure adjustment chamber 502, the main body 256 can deform until it comes into contact with the recess 512 of the end cap 51.

[0058] Rubber portion 257 has an annular base end portion 671 baked onto the inner periphery of main body portion 256, and a cylindrical protruding portion 672 that protrudes from the inner periphery of base end portion 671 to the second side. The diameter of the inner periphery of protruding portion 672 is equal to or smaller than the diameter of the inner periphery of recess 434 of piston nut 43. The thickness of the rubber portion 257 can be set as appropriate. When the pressure in the pressure adjustment chamber 502 is higher than the pressure in the first chamber Y1, the protruding portion 672 of the rubber portion 257 comes into contact with the inner circumferential surface of the recessed portion 434 of the piston nut 43, sealing the pressure adjustment chamber 502. On the other hand, when the pressure in the first chamber Y1 is higher than the pressure in the pressure adjustment chamber 502, the float valve 252 bends around its outer circumferential portion as a fulcrum, and the protruding portion 672 moves away from the inner circumferential surface of the recessed portion 434 of the piston nut 43. This allows oil to flow from the first chamber Y1 to the pressure adjustment chamber 502 through the gap between the inner circumferential portion of the end cap 51 and the inner circumferential surface of the recessed portion 434 of the piston nut 43.

[0059] The float valve 252 configured as described above deforms or displaces during the extension stroke or compression stroke, thereby changing the volume of the pressure adjustment chamber 502. Also, by closing or opening the opening of the recess 434 of the piston nut 43, the float valve 252 blocks or allows the flow of oil between the pressure adjustment chamber 502 and the first chamber Y1 side.

[0060] Furthermore, even if a foreign object is present between the protruding portion 672 of the rubber portion 257 of the float valve 252 and the inner surface of the recessed portion 434 of the piston nut 43 during the extension stroke, the rubber portion 257 deforms to enclose the foreign object, thereby maintaining the airtightness of the pressure adjustment chamber 502. Furthermore, even if foreign matter were to be present between the protruding portion 672 of the rubber portion 257 of the float valve 252 and the inner circumferential surface of the recessed portion 434 of the piston nut 43, the foreign matter would be washed into the pressure adjustment chamber 502 by the oil flowing from the first chamber Y1 to the pressure adjustment chamber 502 during the compression stroke. As a result, foreign matter is unlikely to be present between the protruding portion 672 of the rubber portion 257 of the float valve 252 and the inner circumferential surface of the recessed portion 434 of the piston nut 43, so that the sealing of the pressure adjustment chamber 502 is maintained with high reliability.

[0061] As described above, the shock absorber 202 is provided on the second communication passage (e.g., the pressure chamber 47, the communication passage 43H, the pressure adjustment chamber 502) formed around the rod 20 and communicating between the first chamber Y1 and the second chamber Y2, and includes the float valve 252 (an example of a second valve portion) that closes the second communication passage when the second pressure is higher than the first pressure, elastically deforms to increase the volume of the pressure adjustment chamber 502 (an example of a back pressure chamber) that generates back pressure against the adjustment valve 41, and opens the second communication passage when the first pressure is higher than the second pressure. The shock absorber 202 also includes the piston nut 43 (an example of a forming member) that forms the pressure adjustment chamber 502 together with the float valve 252, and the end cap 51 (an example of a restricting member) that restricts the elastic deformation of the float valve 252, and the outer periphery of the float valve 252 is sandwiched between the piston nut 43 and the end cap 51.

[0062] According to the shock absorber 202 configured as described above, the outer periphery of the float valve 252 is sandwiched between the piston nut 43 and the end cap 51, so there is no need to provide a member (such as a leaf spring) that applies force to the float valve 252 in order to suppress axial movement of the float valve 252. As a result, the axial size of the shock absorber 202 can be reduced.

[0063] The end cap 51 is held by a crimped portion 43K formed by crimping the piston nut 43. This allows the shock absorber 202 to have a simple configuration. The piston nut 43 has a female thread formed in the center that is tightened onto a male thread formed on the rod 20, and a recess 434 that is recessed from the end face on the end cap 51 side is formed around the female thread.The end cap 51 blocks the opening of the recess 434 of the piston nut 43 and has an outer peripheral portion 511 (an example of a base portion) that serves as a base for the float valve 252 when the second pressure is higher than the first pressure, and a recess 512 (an example of a regulating portion) that regulates the elastic deformation of the float valve 252.

[0064] In addition, the end cap 51 is annular and forms a gap between it and the piston nut 43, and the float valve 252 comes into contact with the recess 512 when the second pressure is higher than the first pressure, thereby suppressing the movement of oil from the pressure adjustment chamber 502 to the first chamber Y1, and when the first pressure is higher than the second pressure, it moves away from the recess 512 and allows the movement of liquid from the first chamber Y1 to the pressure adjustment chamber 502 via the gap.

[0065] The float valve 252 also has a metal main body 256 and a rubber part 257 molded from rubber attached to the main body 256. When the second pressure is higher than the first pressure, the rubber part 257 comes into contact with the piston nut 43 to seal the pressure adjustment chamber 502, and when the first pressure is higher than the second pressure, the rubber part 257 separates from the piston nut 43 to allow oil flowing from the first chamber Y1 to move into the pressure adjustment chamber 502. The float valve 252 enables sealing and opening of the pressure adjustment chamber 502 with a simple configuration.

[0066] (Modification of the end cap 51) FIG. 13 is a diagram showing an example of an end cap 251 according to a modified example. In the above-described shock absorber 202, the end cap 51 may have the configuration of an end cap 251 according to a modified example shown in FIG. The end cap 251 differs from the end cap 51 in that it is cylindrically shaped and has an axial through-hole 251H formed therein. For example, a plurality of through-holes 251H may be provided in the circumferential direction. For example, the radial position of the through-hole 251H may be the same as the radial position of the recess 434 of the piston nut 43. By forming the through-hole 251H in the end cap 251, when the pressure in the first chamber Y1 becomes higher than the pressure in the pressure adjustment chamber 502 during the compression stroke, oil flows from the first chamber Y1 into the pressure adjustment chamber 502 through the through-hole 251H.

[0067] As described above, the end cap 251 according to the modified example is formed with a through-hole 251H in the axial direction of the rod 20 so as to communicate between the pressure adjustment chamber 502 and the first chamber Y1. When the second pressure is higher than the first pressure, the float valve 252 comes into contact with the recess 512 to block the through-hole 251H and suppress the movement of oil from the pressure adjustment chamber 502 to the first chamber Y1, and when the first pressure is higher than the second pressure, the float valve 252 moves away from the recess 512 to allow the movement of oil from the first chamber Y1 to the pressure adjustment chamber 502. Even with this configuration, the float valve 252 can seal and open the pressure adjustment chamber 502 with a simple configuration.

[0068] Third Embodiment FIG. 14 is a diagram showing an example of a cross section of a shock absorber 302 according to the third embodiment. FIG. 15 is a diagram illustrating an example of the operation of the float valve 352 according to the third embodiment. A shock absorber 302 according to the third embodiment differs from the shock absorber 202 according to the second embodiment in that a recess 534 corresponding to the recess 434 of the piston nut 43 is formed in a cylindrical shape, and a first-side mounting portion 521 corresponding to the first-side mounting portion 21 of the rod 20 is formed. The shock absorber 302 differs from the shock absorber 202 in that a pressure adjustment chamber 503 corresponding to the pressure adjustment chamber 500 is formed by the recess 534 of the piston nut 43, a float valve 352 corresponding to the float valve 252, and the first-side mounting portion 521 of the rod 20. Differences from the second embodiment will be described below. The same components in the second and third embodiments are designated by the same reference numerals, and detailed description thereof will be omitted.

[0069] The first-side mounting portion 521 of the rod 20 has a threaded portion 522 formed with a male thread that is fastened to the bolt hole 43R of the piston nut 43, and a cylindrical protruding portion 523 provided on the first side of the threaded portion 522. The outer diameter of the protruding portion 523 is smaller than the outer diameter of the threaded portion 522. End cap 351, which corresponds to end cap 51, differs from end cap 51 in that it has a smaller inner diameter, which is smaller than the diameter of bolt hole 43R of piston nut 43 and larger than the diameter of the outer circumferential surface of protrusion 523 of rod 20. Protrusion 523 of rod 20 is inserted inside end cap 351, and a gap is formed between the inner circumferential surface of end cap 351 and the outer circumferential surface of protrusion 523.

[0070] The float valve 352 has a smaller inner diameter of the main body 256 than the float valve 252, and is formed so that when the pressure in the pressure adjustment chamber 503 is higher than the pressure in the first chamber Y1, the protrusion 672 of the rubber part 257 comes into contact with the outer surface of the protrusion 523 of the rod 20 to seal the pressure adjustment chamber 503. When the pressure in the first chamber Y1 is higher than the pressure in the pressure adjustment chamber 503, the inner circumferential portion of the float valve 352 bends from the outer circumferential portion as a base point, and the protruding portion 672 moves away from the outer circumferential surface of the protruding portion 523 of the rod 20. This allows oil to flow from the first chamber Y1 to the pressure adjustment chamber 503 through the gap between the protruding portion 523 of the rod 20 and the end cap 351.

[0071] The float valve 352 configured as described above deforms or displaces during the extension stroke or compression stroke, thereby changing the volume of the pressure adjustment chamber 503. Also, by closing or opening the opening of the recess 534 of the piston nut 43, the float valve 352 blocks or allows the flow of oil between the pressure adjustment chamber 503 and the first chamber Y1 side.

[0072] Furthermore, even if a foreign object is present between the protrusion 672 of the rubber part 257 of the float valve 352 and the outer peripheral surface of the protrusion 523 of the rod 20 during the extension stroke, the rubber part 257 deforms to enclose the foreign object, thereby maintaining the airtightness of the pressure adjustment chamber 503. Furthermore, even if foreign matter were to exist between the protruding portion 672 of the rubber portion 257 of the float valve 352 and the outer peripheral surface of the protruding portion 523 of the rod 20, the foreign matter would be washed into the pressure adjustment chamber 503 by the oil flowing from the first chamber Y1 to the pressure adjustment chamber 503 during the compression stroke. As a result, foreign matter is unlikely to exist between the protruding portion 672 of the rubber portion 257 of the float valve 352 and the outer peripheral surface of the protruding portion 523 of the rod 20, so that the sealing of the pressure adjustment chamber 503 is maintained with high reliability.

[0073] As described above, the shock absorber 302 is provided on the second communication passage (e.g., the pressure chamber 47, the communication passage 43H, the pressure adjustment chamber 503) formed around the rod 20 and communicating between the first chamber Y1 and the second chamber Y2, and includes the float valve 352 (an example of a second valve portion) that closes the second communication passage when the second pressure is higher than the first pressure, elastically deforms to increase the volume of the pressure adjustment chamber 503 (an example of a back pressure chamber) that generates back pressure against the adjustment valve 41, and opens the second communication passage when the first pressure is higher than the second pressure. The shock absorber 302 also includes the piston nut 43 (an example of a forming member) that forms the pressure adjustment chamber 503 together with the float valve 352, and the end cap 351 (an example of a restricting member) that restricts the elastic deformation of the float valve 352, and the outer periphery of the float valve 352 is sandwiched between the piston nut 43 and the end cap 351.

[0074] According to the shock absorber 302 configured as described above, the outer periphery of the float valve 352 is sandwiched between the piston nut 43 and the end cap 351, so there is no need to provide a member (such as a leaf spring) that applies force to the float valve 352 in order to suppress axial movement of the float valve 352. As a result, the axial size of the shock absorber 302 can be reduced.

[0075] In the shock absorber 302 , the pressure adjusting chamber 503 is composed of the piston nut 43 , the float valve 352 , and the rod 20 . The float valve 352 also has a metal main body 256 and a rubber part 257 molded from rubber attached to the main body 256. When the second pressure is higher than the first pressure, the rubber part 257 comes into contact with the rod 20 to seal the pressure adjustment chamber 503, and when the first pressure is higher than the second pressure, the rubber part 257 separates from the rod 20 to allow oil flowing from the first chamber Y1 to move into the pressure adjustment chamber 503. The float valve 352 allows the pressure adjustment chamber 503 to be sealed and opened with a simple configuration.

[0076] (Modification of end cap 351) FIG. 16 is a diagram showing an example of an end cap 451 according to a modified example. In the above-described shock absorber 302, the end cap 351 may have the configuration of an end cap 451 according to a modified example shown in FIG. The end cap 451 differs from the end cap 351 in that it is formed in a cylindrical shape and has an axial through-hole 451H formed therein. For example, a plurality of through-holes 451H may be provided in the circumferential direction. Furthermore, the end cap 451 has a central recess 452 formed in the center thereof, recessed in a cylindrical shape from the end face on the second side. The central recess 452 is recessed so as not to come into contact with the protruding portion 523 of the first-side mounting portion 521 of the rod 20. The through-hole 451H is formed outside the central recess 452. Because a through hole 451H is formed in the end cap 451, when the pressure in the first chamber Y1 becomes higher than the pressure in the pressure adjustment chamber 503 during the compression stroke, oil flows from the first chamber Y1 into the pressure adjustment chamber 503 through the through hole 451H.

[0077] As described above, the end cap 451 according to the modified example is formed with a through-hole 451H in the axial direction of the rod 20 so as to connect the pressure adjustment chamber 503 and the first chamber Y1. When the second pressure is higher than the first pressure, the float valve 352 comes into contact with the recess 512 to block the through-hole 451H and suppress the movement of oil from the pressure adjustment chamber 503 to the first chamber Y1, and when the first pressure is higher than the second pressure, the float valve 352 moves away from the recess 512 to allow the movement of oil from the first chamber Y1 to the pressure adjustment chamber 503. Even with this configuration, the float valve 352 can seal and open the pressure adjustment chamber 503 with a simple configuration. [Explanation of symbols]

[0078] 1...suspension device, 2,202,302...shock absorber, 3...coil spring, 10...cylinder portion, 20...rod, 30...piston portion, 31...piston, 40...damping force change portion, 41...adjustment valve (an example of a first valve portion), 43...piston nut (an example of a forming member), 43K...crimping portion, 48...forming member, 49...nut (an example of a restricting member), 51,251,351,451...end cap (an example of a restricting member), 249H,251H,451H...through hole, 52,252,352...float valve (an example of a second valve portion), 56...main body portion, 57,257...rubber portion, 500,502,503...pressure adjustment chamber, 511...outer periphery (an example of a base portion), 512...recess (an example of a restricting portion), Y1...first chamber, Y2...second chamber

Claims

1. a first valve portion disposed in a first communication passage that communicates a first chamber and a second chamber defined by a piston held by a rod, the first valve portion opening the first communication passage when a second pressure, which is a pressure in the second chamber, is higher than a first pressure, which is a pressure in the first chamber, and closing the first communication passage when the first pressure is higher than the second pressure; a second valve section provided on a second communication passage formed around the rod and communicating the first chamber with the second chamber, the second valve section elastically deforming to close the second communication passage when the second pressure is higher than the first pressure and to increase the volume of a back pressure chamber that generates back pressure against the first valve section, and opening the second communication passage when the first pressure is higher than the second pressure; a forming member that forms the back pressure chamber together with the second valve portion; a restricting member that restricts elastic deformation of the second valve portion; Equipped with The second valve portion has an inner circumferential portion or an outer circumferential portion sandwiched between the forming member and the restricting member. Buffer device.

2. The restricting member has a female thread formed thereon to be fastened to a male thread formed on the rod, an inner circumferential portion of the second valve portion is sandwiched between the forming member and the regulating member, and the second valve portion is held by an axial force generated when the regulating member is tightened onto the rod; The shock absorber according to claim 1 .

3. an outer periphery of the second valve portion is sandwiched between the forming member and the restricting member; The restricting member is held by a crimped portion formed by crimping the forming member. The shock absorber according to claim 1 .

4. The back pressure chamber is composed of the forming member, the second valve portion, and the rod. The shock absorber according to claim 3.

5. The forming member has a female screw formed in a central portion thereof to be fastened to the male screw formed in the rod, and a recess formed around the female screw, the recess being recessed from the end face on the side of the restricting member, the restricting member closes the opening of the recess of the forming member and has a seat portion that serves as a seat for the second valve portion when the second pressure is higher than the first pressure, and a restricting portion that restricts the elastic deformation of the second valve portion. The shock absorber according to claim 1 .

6. the restricting member is annular, and forms a gap between the restricting member and the forming member or the rod; When the second pressure is higher than the first pressure, the second valve portion comes into contact with the regulating portion to suppress movement of liquid from the back pressure chamber to the first chamber, and when the first pressure is higher than the second pressure, the second valve portion moves away from the regulating portion to allow movement of liquid from the first chamber to the back pressure chamber via the gap. The shock absorber according to claim 5.

7. The restricting member has a through hole formed in the axial direction of the rod so as to communicate between the back pressure chamber and the first chamber, When the second pressure is higher than the first pressure, the second valve portion comes into contact with the regulating portion to block the through hole and suppress movement of liquid from the back pressure chamber to the first chamber, and when the first pressure is higher than the second pressure, the second valve portion moves away from the regulating portion to allow movement of liquid from the first chamber to the back pressure chamber. The shock absorber according to claim 5.

8. The second valve portion has a metal main body portion and a rubber portion molded from rubber attached to the main body portion, When the second pressure is higher than the first pressure, the rubber portion comes into contact with the forming member to seal the back pressure chamber, and when the first pressure is higher than the second pressure, the rubber portion separates from the forming member to allow the liquid flowing from the first chamber to move into the back pressure chamber. The shock absorber according to claim 2 .

9. The second valve portion has a metal main body portion and a rubber portion molded from rubber attached to the main body portion, the rubber portion comes into contact with the rod to seal the back pressure chamber when the second pressure is higher than the first pressure, and separates from the rod to allow the liquid flowing from the first chamber to move into the back pressure chamber when the first pressure is higher than the second pressure. The shock absorber according to claim 4.

10. A shock absorber according to any one of claims 1 to 9; a coil spring disposed around the shock absorber; A suspension device comprising:

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