Damping valve and shock absorber

Abstract

This damper valve (EV, CV) is provided with: an annular valve body (21, 27) having a fixed end and a free end; the valve seat members (20, 26) are provided with: annular opposing seat sections (20b, 26b) which are annular and which face the circumferential surfaces of the free end sides of the valve bodies (21, 27); ports (20c, 26d) which are provided closer to the fixed end sides of the valve bodies (21, 27) than the opposing seat sections (20b, 26b); annular valve seats (20e, 26f) which face the valve bodies (21, 27) in the axial direction and on which the valve bodies (21, 27) can be seated away from each other; and annular seat sections (20f, 26g) which abut against the fixed end sides of the valve bodies (21, 27). Seat surfaces (20f1, 26g1), on which the valve bodies (21, 27) are seated, of the seat parts (20f, 26g) are provided with inclined surfaces (20f2, 26g2) that are inclined in a direction away from the valve bodies (21, 27) from the fixed end sides of the valve bodies (21, 27) toward the free end sides of the valve bodies (21, 27).

Description

Technical Field

[0001] The invention relates to a damping valve and a buffer. Background Art

[0002] The shock absorber is, for example, interposed between the vehicle body and wheels to improve the ride comfort of the vehicle. The damping force generated by the shock absorber during expansion and contraction can suppress the vibration of the vehicle body and wheels.

[0003] This type of buffer, for example, includes a cylinder, a rod that can be freely movably inserted into the cylinder, a piston that can be freely slidably inserted into the cylinder and divides the interior of the cylinder into an extension side chamber and a compression side chamber, a free piston that can be freely slidably inserted into the cylinder and divides the lower part of the compression side chamber inside the cylinder into a gas chamber, a damping channel arranged on the piston and connecting the extension side chamber and the compression side chamber, and a damping valve arranged on the damping channel.

[0004] In recent years, in order to improve vehicle ride comfort, the following damping force characteristic requirements have been proposed for vehicle shock absorbers: in the micro-low speed range (lower than low speed) of telescopic speed, the damping coefficient is increased, and the damping force is rapidly increased with the switching of the telescopic stroke, while the damping coefficient in the low speed range is smaller than that in the micro-low speed range. Furthermore, in the medium-high speed range (higher than low speed), the damping coefficient is proportional to the telescopic speed, but smaller than that in the low speed range.

[0005] In order to meet such needs, as shown in Japanese patent JP2019-183918A, the damping valve includes a leaf valve and a valve seat component, wherein the leaf valve is annular and the inner peripheral side is fixed while the outer peripheral side is allowed to flex, and the valve seat component is annular and has an annular relatively arranged seat portion opposite to the outer periphery of the leaf valve without contact and a port on the inner peripheral side of the relatively arranged seat portion. The damping valve applies resistance to the flow of hydraulic oil shuttling between the extension side chamber and the compression side chamber.

[0006] In a damping valve constructed in this manner, when the buffer's expansion and contraction speed is within the slightly low-speed range, the leaf valve hardly flexes, thereby limiting the flow path area between it and the relatively arranged seat portion to an extremely small value. Therefore, a damping force characteristic that can increase sharply relative to the expansion and contraction speed can be obtained, thereby achieving a damping force characteristic that is more suitable for the vehicle. Prior art literature Patent Literature

[0007] Patent Document 1: JP2019-183918A Summary of the Invention Problems to be solved by the invention

[0008] Traditional damping valves have leaf valves and relatively arranged seats, so the damping force characteristics of the buffer are good when it is extended and retracted at a very low speed. However, since the leaf valve bends and opens when the buffer is extending or retracting, it is impossible to obtain different damping force characteristics when extending and retracting.

[0009] Alternatively, a valve seat can be provided that abuts the leaf valve and closes the port when the leaf valve deflects relative to the valve seat member. This allows the damping valve to open only when hydraulic oil is flowing to one port, allowing the damping valve to also function as a check valve. While this arrangement allows the leaf valve to seal the port when seated on the valve seat, the leaf valve may bend and deform at the flexure point when the free end of the leaf valve deflects toward the valve seat, potentially causing fatigue in the leaf valve.

[0010] Therefore, an object of the present invention is to provide a damping valve that can suppress fatigue of a leaf valve and function as a check valve, and a shock absorber equipped with the damping valve that can improve vehicle ride comfort. Solutions to Problems

[0011] To address the aforementioned issues, the damping valve of the present invention comprises an annular valve body and a valve seat member, wherein one of the inner or outer circumferences of the annular valve body serves as a fixed end, while the other serves as a free end, allowing the free end to flex relative to the fixed end. The valve seat member is annular and comprises an annular opposing seat portion opposing at least a portion of a circumferential surface on the free end side of the valve body, a port disposed radially closer to the fixed end side of the valve body than the opposing seat portion, an annular valve seat disposed between the opposing seat portion and the port and axially opposing the valve body so that the valve body can be removably seated thereon, and an annular seat portion disposed radially closer to the fixed end side of the valve body than the port and abutting the fixed end side of the valve body. The seat portion has a seat surface on which the valve body seats, the seat surface having an inclined surface inclined in a direction away from the valve body from the fixed end side toward the free end side of the valve body.

[0012] With this damping valve structure, when the valve body is subjected to pressure from the port side, it flexes, opening the port and resisting the flow of liquid through the port. When the valve body is subjected to pressure pressing toward the valve seat member, the valve body seats on the annular valve seat, blocking the port. Consequently, the valve body functions as a damping valve for liquid flowing through the port from one side and as a check valve for liquid flowing through the port from the other side. Furthermore, with this damping valve structure, since the seat surface of the seat portion includes an inclined surface, the fixed end side of the valve body can deform along the inclined surface, thereby reducing bending deformation at the flexure fulcrum and minimizing the amount of valve body deformation.

[0013] Furthermore, the damping valve includes an annular gasket laminated on the side of the valve body opposite the valve seat member and serving as a fulcrum for the deflection of the free end of the valve body. The inclined surface may also be formed radially closer to the free end of the valve body than the gasket on the seat surface. A damping valve constructed in this manner prevents unnecessary initial deflection of the valve body, thereby preventing the valve body from shifting relative to the opposing seat portion and thereby preventing fluctuations in the damping force.

[0014] Furthermore, the shock absorber of the present invention comprises a shock absorber body and a damping valve disposed between working chambers. The shock absorber body comprises an outer tube, a rod inserted axially movably into the outer tube, and at least two working chambers in which the rod moves relative to the outer tube to cause reciprocating movement of a liquid. In this shock absorber structure, because the damping valve also functions as a check valve, the damping force characteristics during the shock absorber's extension and contraction can be independently set. Within the slightly low-speed range of extension and contraction speeds, the damping coefficient increases, and the damping force rapidly increases with the switching of the extension and contraction strokes. While the damping coefficient within the low-speed range is smaller than within the slightly low-speed range, a damping force characteristic that suppresses vehicle body vibration can be achieved, thereby improving vehicle ride comfort. Effects of the Invention

[0015] According to the damping valve of the present invention, fatigue of the leaf valve can be suppressed and the damping valve can function as a check valve. Therefore, the shock absorber of the present invention can improve the ride comfort of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a longitudinal sectional view of a shock absorber to which a damping valve according to an embodiment of the present invention is applied. Figure 2 This is a partially enlarged cross-sectional view of a shock absorber to which a damping valve according to an embodiment of the present invention is applied. Figure 3 (A) is a partially enlarged cross-sectional view of the extension-side auxiliary valve. Figure 3 (B) is a partially enlarged cross-sectional view of the compression-side auxiliary valve. Figure 4 FIG. 1 is a diagram showing the damping force characteristics of a shock absorber to which the damping valve according to one embodiment of the present invention is applied. DETAILED DESCRIPTION

[0017] The present invention will be described below based on the embodiments shown in the drawings. Figure 1 and Figure 2As shown, a shock absorber D in one embodiment includes: a telescopic shock absorber body A having a cylinder 1 as an outer tube and a rod 2 movably inserted into the cylinder 1; an extension-side auxiliary valve EV and a compression-side auxiliary valve CV serving as damping valves, which are disposed between two working chambers, an extension-side chamber R1 and a compression-side chamber R2, which are disposed within the shock absorber body A. Furthermore, when the shock absorber D is used, it can be interposed between a vehicle body and a wheel (not shown) to suppress vibrations of the vehicle body and the wheel.

[0018] Next, each part of the buffer D is described in detail. Figure 1 As shown, the buffer body A comprises: a cylindrical cylinder 1 with a bottom, which serves as an outer tube; a rod 2, which is movably inserted into the cylinder 1; and a piston 3, which is connected to the rod 2 and, while being movably inserted into the cylinder 1, divides the cylinder 1 into an extension side chamber R1 and a compression side chamber R2 serving as a working chamber.

[0019] Moreover, the rod 2 Figure 1 A bracket (not shown) is provided at the upper end, or base end, of the cylinder 1, and the rod 2 is connected to one of the vehicle body and the wheel via the bracket (not shown). Furthermore, a bracket (not shown) is also provided at the bottom 1a of the cylinder 1, and the cylinder 1 is connected to the other of the vehicle body and the wheel via the bracket (not shown).

[0020] In this way, the shock absorber D is sandwiched between the vehicle body and the wheel. Furthermore, if the wheel vibrates up and down relative to the vehicle body, such as when the vehicle is traveling on an uneven road, the rod 2 moves in and out of the cylinder 1, causing the shock absorber D to expand and contract, while the piston 3 moves up and down (axially) within the cylinder 1.

[0021] The damper body A also includes an annular guide 10 that closes the upper end of the cylinder 1 and allows the rod 2 to slide freely through its inner circumference. This creates a sealed space within the cylinder 1. Furthermore, a free piston 11 is slidably inserted on the side opposite the rod 2, as viewed from the piston 3 within the cylinder 1.

[0022] A liquid chamber L is formed above the free piston 11 in the cylinder 1, and a gas chamber G is formed below. Furthermore, the liquid chamber L is divided by the piston 3 into an expansion-side chamber R1 on the rod 2 side and a compression-side chamber R2 on the piston 3 side. Each of the expansion-side chamber R1 and the compression-side chamber R2 is filled with liquid. The liquid filling the shock absorber body A can also be hydraulic oil, water, an aqueous solution, or other liquids. Meanwhile, the gas chamber G contains compressed air, nitrogen, or other gas.

[0023] Furthermore, when the shock absorber D extends, the rod 2 withdraws from the cylinder 1, increasing the volume within the cylinder. When the increase reaches the volume of the withdrawn rod 2, the free piston 11 moves upward within the cylinder 1, expanding the gas chamber G. Conversely, when the shock absorber D contracts, the rod 2 enters the cylinder 1, decreasing the volume within the cylinder. When the decrease reaches the volume of the entered rod 2, the free piston 11 moves downward within the cylinder 1, shrinking the gas chamber G.

[0024] Furthermore, the liquid chamber L and the gas chamber G may be partitioned by an air bag, a bellows, or the like instead of the free piston 11, and the structure of the movable partition wall serving as the partition may be appropriately changed.

[0025] Furthermore, in this embodiment, the damper D is a single-rod, single-cylinder type. When the damper D is extended or retracted, the free piston 11 expands or contracts the gas chamber G to compensate for the volume generated by the rod 2 entering or exiting the cylinder 1. However, the structure for this volume compensation may be appropriately modified.

[0026] For example, if the free piston 11 and gas chamber G are eliminated and an outer tube is provided on the outer periphery of the cylinder 1, a liquid storage chamber is formed between the cylinder 1 and the outer tube to store liquid, and the damper is a multi-tube type, the liquid storage chamber can also compensate for the volume generated by the rod 2 entering or exiting the cylinder 1. Alternatively, the liquid storage chamber can be formed in a liquid reservoir located separately from the cylinder 1. Furthermore, the damper D can be configured as a double-rod type damper, with the piston 3 mounted in the center of the rod 2 and the ends of the rod 2 protruding from both ends of the cylinder 1.

[0027] The rod 2 is cylindrical and has a reduced outer diameter on the front end side, and comprises a small diameter portion 2a having the smallest diameter on the front end side, and a portion having an outer diameter larger than the small diameter portion 2a and provided on the small diameter portion 2a. Figure 2 The large diameter portion 2b on the upper middle side, the step portion 2c provided at the junction of the small diameter portion 2a and the large diameter portion 2b, the threaded portion 2d provided on the outer periphery of the front end of the small diameter portion 2a, and the threaded portion 2d provided further to the outside than the threaded portion 2d of the small diameter portion 2a. Figure 2 Four through holes 2e, 2f, 2g, and 2h are located in the upper middle portion and are staggered with each other and connect the inside and outside of the small-diameter portion 2a.

[0028] The valve seat component 20, valve body 21, gasket 22 and valve stopper 23, liner 24, partition component 25 on the extension side auxiliary valve EV, the valve seat component 26, valve body 27, gasket 28 and valve stopper 29 on the compression side auxiliary valve CV, main valve stopper 6, compression side main valve 5, piston 3, and extension side main valve 4 are assembled in sequence on the small diameter portion 2a of the rod 2, and are fixed by a piston nut 33 screwed onto the threaded portion 2d at the front end of the small diameter portion 2a.

[0029] like Figure 1 and Figure 2 As shown, the piston 3 is annular and fixed to the outer periphery of the small diameter portion 2a of the rod 2 and in sliding contact with the inner periphery of the cylinder 1, thereby dividing the interior of the cylinder 1 into Figure 1 The elongated side chamber R1 on the upper middle side and Figure 1 The compression side chamber R2 is located in the middle and lower part. In addition, the piston 3 is provided with an expansion side passage 3a and a compression side passage 3b for communicating the expansion side chamber R1 with the compression side chamber R2.

[0030] Piston 3 Figure 2 The lower end of the piston 2 is stacked with an extension-side main valve 4. This annular extension-side main valve is fitted onto the outer periphery of the small-diameter portion 2a of the rod 2 and is used to open or close the extension-side passage 3a. The extension-side main valve 4 is a laminated leaf valve composed of multiple annular plates. Its inner periphery is fixed to the small-diameter portion 2a of the rod 2, allowing for deflection on the outer periphery. When seated on the lower end of the piston 3, the extension-side main valve 4 closes the lower outlet of the extension-side passage 3a. If the outer periphery is deflected away from the piston 3, the extension-side passage 3a is opened and resistance is applied to the flow of liquid from the extension-side chamber R1 to the compression-side chamber R2 through the extension-side passage 3a. Furthermore, the extension-side main valve 4, seated on the piston 3, closes the extension-side passage 3a, preventing the flow of liquid from the compression-side chamber R2 to the extension-side chamber R1.

[0031] Piston 3 Figure 2 The upper end of the compression side main valve 5 is stacked with the compression side main valve 5, which is annular and is embedded in the outer periphery of the small diameter portion 2a of the rod 2, and is used to open or close the compression side channel 3b. The compression side main valve 5 is a stacked leaf valve composed of a plurality of stacked annular plates, the inner peripheral side of which is fixed to the small diameter portion 2a of the rod 2, allowing the outer peripheral side to bend. Moreover, the compression side main valve 5 closes the outlet end of the upper end of the compression side channel 3b when it is seated on the upper end of the piston 3. If the outer peripheral side is bent and separated from the piston 3, the compression side channel 3b is opened, and resistance is applied to the flow of liquid passing through the compression side channel 3b from the compression side chamber R2 to the extension side chamber R1. In addition, for the flow of liquid flowing from the extension side chamber R1 to the compression side chamber R2, the compression side main valve 5 is seated on the piston 3 to close the compression side channel 3b. In addition, the compression side main valve 5 Figure 2 A main valve stopper 6 is stacked in the upper middle portion. When the compression-side main valve 5 is significantly deflected, the main valve stopper 6 abuts against the side of the compression-side main valve 5 opposite the piston, supporting the compression-side main valve 5 and preventing excessive stress from acting on the compression-side main valve 5, thereby protecting the compression-side main valve 5.

[0032] In this embodiment, if Figure 2As shown in FIG. 1 , the extension-side auxiliary valve EV used as a damping valve comprises a valve seat member 20, a valve body 21, and a gasket 22. The valve seat member 20 is annular and comprises: a partition body 20a in the form of an open disk fitted on the outer periphery of the small-diameter portion 2a; Figure 2 The outer periphery of the middle and lower end is projected downwardly, and the relative seat portion 20b is arranged at a position lower than the separator 20a. Figure 2 The lower end of the relative seat portion 20b is closer to the inner circumference and multiple ports 20c are arranged on the same circumference, and the separator 20a is provided with a plurality of ports 20c. Figure 2 The window 20d of the annular recessed portion is provided at the lower end of the separator 20a and communicates with the outlet end of each port 20c. Figure 2 An annular valve seat 20e protrudes downward from between the opposing seat portion 20b and the port 20c at the middle lower end, and an annular inner peripheral seat portion 20f is provided on the inner peripheral portion of the window 20d.

[0033] The opposing seat portion 20b surrounds the outer circumference of the annular valve seat 20e, leaving a gap with respect to the partition body 20a. It protrudes downward and extends beyond the lower end of the annular valve seat 20e. Specifically, as viewed from the partition body 20a, the opposing seat portion 20b is higher than the annular valve seat 20e. The height difference between the opposing seat portion 20b and the annular valve seat 20e is at least greater than the combined axial thickness of the backup valve 21b and the annular plate 21a1 of the leaf valve 21a of the valve body 21, described below. Furthermore, in this embodiment, since the inner circumference of the valve body 21 is the fixed end and the outer circumference is the free end, the annular valve seat 20e is radially located on the fixed end side (inner circumference side) of the opposing seat portion 20b of the valve seat member 20.

[0034] In addition, in the present embodiment, the relatively arranged seat portion 20b and the annular valve seat 20e protrude axially relative to the partition body 20a, and an annular recess is formed between the relatively arranged seat portion 20b and the annular valve seat 20e. However, in the case where the inner circumferential side of the valve body 21 is a fixed end, the annular valve seat 20e is provided on the inner circumferential side of the relatively arranged seat portion 20b. If the height of the relatively arranged seat portion 20b is higher than the annular valve seat 20e as described above, the relatively arranged seat portion 20b and the annular valve seat 20e can be provided to protrude axially from the partition body 20a as a whole without an annular recess between the two.

[0035] The inner peripheral seat portion 20f is a seat portion that abuts against the fixed end side of the valve body 21. Figure 2 The inner peripheral side of the window 20d at the lower end protrudes downward and is axially opposite to the valve body 21. The lower end is provided with an annular seat surface 20f1 that abuts against the fixed end (inner peripheral portion) of the valve body 21. Figure 3As shown in Figure (A), the seat surface 20f1 includes an inclined surface 20f2 on its outer periphery, which slopes away from the valve body 21 from the fixed end toward the free end. Since the inner periphery of the valve body 21 is the fixed end, while the outer periphery of the valve body 21 is the free end, the inner periphery of the inclined surface 20f2 of the inner periphery seat portion 20f is higher than the outer periphery when viewed from the partition 20a. Overall, the outer periphery of the inclined surface 20f2 of the seat surface 20f1 slopes further away from the valve body 21 than the inner periphery. Furthermore, the inner periphery of the inclined surface 20f2 of the seat surface 20f1 is horizontal, and when the valve body 21 is mounted on the small-diameter portion 2a of the rod 2, it, together with the gasket 22, holds the inner periphery of the valve body 21. The inclined surface 20f2 smoothly connects to the horizontal surface, ensuring that the slope does not change sharply at the interface between the inclined surface 20f2 of the seat surface 20f1 and the horizontal surface on the inner periphery of the inclined surface 20f2. In addition, in this embodiment, the inclined surface 20f2 of the seat surface 20f1 is a tapered inclined surface, but it can also be a curved surface. Figure 3 (A) The height of the horizontal plane at the lower end is higher than that of the annular valve seat 20e. Figure 2 The height of the middle lower end surface (seat surface) is lower than the opposite seat portion 20b.

[0036] like Figure 2 As shown, the valve body 21 is composed of a leaf valve 21a, which is composed of multiple annular plates, the inner peripheral side of which is fixed to the small diameter portion 2a and serves as a fixed end, and the outer peripheral side that allows flexibility serves as a free end; and a backup valve 21b, which is stacked on the valve seat member side of the leaf valve 21a. This valve body is stacked on the partition 20a of the valve seat member 20. Figure 2 The lower end of the middle part is fixed to the outer periphery of the small diameter part 2a.

[0037] The leaf valve 21a is composed of three elastic annular plates 21a1, 21a2, and 21a3. The inner diameters of the three plates are all set to fit on the outer periphery of the small diameter portion 2a. Figure 2 The leaf valve 21a comprises an annular plate 21a1 at the top, which has the largest outer diameter and is elastic; an annular plate 21a2, which has a smaller outer diameter than annular plate 21a1 and is stacked on the side of annular plate 21a1 opposite the valve seat member; and an annular plate 21a3, which has a smaller outer diameter than annular plate 21a2 and is stacked on the side of annular plate 21a2 opposite the valve seat member. The number of annular plates constituting the leaf valve 21a can be varied as appropriate depending on the desired damping force characteristics, and a single annular plate may be sufficient.

[0038] The backup valve 21b is stacked on the annular plate 21a1 having the largest outer diameter of the leaf valve 21a. Figure 2The upper side, i.e. the valve seat member side, is an annular plate having an outer diameter smaller than that of the annular plate 21a1 and an inner diameter equal to that of the annular plate 21a1. In addition, in this case, the outer diameter of the backup valve 21b is larger than the inner diameter of the seat surface at the lower end of the annular valve seat 20e.

[0039] Furthermore, when the valve body 21 of this structure is overlapped with the inner circumferential seat portion 20f of the partition 20a of the valve seat member 20, the inner circumferential seat portion 20f is higher than the annular valve seat 20e. Consequently, the valve body 21 and the annular valve seat 20e are axially opposed, creating an axial gap between the backup valve 21b and the annular valve seat 20e. Furthermore, the outer circumferential surface of the free end of the annular plate 21a1, which has the largest outer diameter, of the leaf valve 21a is radially opposed to the inner circumferential surface of the opposing seat portion 20b of the valve seat member 20, with a slight gap formed therebetween. When the leaf valve 21a is facing the opposing seat portion 20b, the gap between the leaf valve 21a and the opposing seat portion 20b is extremely small, making it difficult for liquid to pass through this gap. This state is considered the closed state of the extension-side auxiliary valve EV. In addition, if at least a portion of the outer peripheral surface of the free end side of the valve body 21 is radially opposite to the relatively set seat portion 20b, the extension side auxiliary valve EV can open or close the port 20c. Therefore, the entire outer peripheral surface of the annular plate 21a1 does not need to be radially opposite to the entire inner peripheral surface of the relatively set seat portion 20b.

[0040] The outer diameter of the gasket 22 stacked on the side of the valve body 21 opposite to the valve seat member is smaller than the outer diameter of the annular plate 21a3 disposed on the side of the leaf valve 21a opposite to the valve seat member and furthest from the valve seat member, and the inner diameter of the inclined surface 20f2 on the seat surface 20f1 of the inner peripheral seat portion 20f, and is fixed to the small diameter portion 2a in an unmovable manner. In addition, although the gasket 22 is composed of a single annular plate, it can also be composed of multiple annular plates. Therefore, the leaf valve 21a and the backup valve 21b of the valve body 21 are not removably fixed to the small diameter portion 2a when they are subjected to the pressure from the valve seat member 20. Figure 2 When the pressure of the liquid passes through the port 20c downward, the outer peripheral edge of the gasket 22 is used as a fulcrum to move the outer peripheral side. Figure 2 The leaf valve 21a deflects downward in the center of the valve body. As a result, the outer circumference of the leaf valve 21a no longer directly faces the inner circumference of the opposing seat 20b in the radial direction, but is instead offset downward relative to the opposing seat 20b. The area of ​​the flow path formed by the gap between the leaf valve 21a and the opposing seat 20b increases as the deflection of the leaf valve 21a increases. Thus, when the leaf valve 21a is no longer offset from the opposing seat 20b, the extension-side auxiliary valve EV opens. The extension-side auxiliary valve EV allows liquid to flow through the gap via the valve body 21, while also resisting the flow of liquid.

[0041] In addition, the leaf valve 21a and the backup valve 21b of the valve body 21 are subjected to the pressure from the valve seat member 20. Figure 3(A) When the pressure of the liquid passes through the port 20c upward, the outer peripheral side is moved toward the inner peripheral edge of the inclined surface 20f2 of the seat surface 20f1 of the inner peripheral seat portion 20f of the valve seat member 20. Figure 3 (A) The upward deflection. When the valve body 21 deflects by a predetermined amount or more, the backup valve 21b is seated on the annular valve seat 20e to close the port 20c.

[0042] If the entire seat surface 20f1 of the inner circumferential seat portion 20f is horizontal, the valve body 21 will bend and deform at the flexure fulcrum when the free end of the valve body 21 is bent toward the valve seat member. Conversely, by providing the seat surface 20f1 of the inner circumferential seat portion 20f, which serves as the seat portion, with the inclined surface 20f2, the inner circumference of the valve body 21 can deform along the inclined surface 20f2, thereby reducing the bending deformation at the flexure fulcrum. Moreover, by positioning the flexure fulcrum of the inner circumference of the valve body 21 closer to the inner circumference, the radial length of the flexible portion of the valve body 21 that is not fixed is increased, thereby reducing the amount of deformation of the inner circumference of the valve body 21. This can reduce the stress acting on the inner circumference of the valve body 21 when the valve body 21 is bent toward the valve seat member. In addition, the radial length of the flexible portion of the valve body 21 that is not fixed becomes longer. When the valve body 21 bends toward the valve seat member, the annular valve seat 20e of the valve body 21 is relatively Figure 3 (A) The slope of the lower end surface decreases, making it easier for the valve body 21 to touch the lower end surface of the annular valve seat 20e, so that the valve body 21 fits tightly with the lower end surface as a whole.

[0043] In this way, the extension side auxiliary valve EV used as a damping valve is Figure 2 When the liquid flows downward through the port 20c, the free end of the valve body 21 bends toward the side opposite to the valve seat member to open the valve and allow the liquid to flow. Figure 2When fluid flows upward through port 20c, the free end of valve body 21 deflects toward the valve seat member and seats on annular valve seat 20e, blocking the flow. In this way, the extension-side auxiliary valve EV functions as a damping valve, opening the valve to allow fluid flow through port 20c from one side and applying resistance to the fluid. Conversely, it also functions as a check valve, closing the valve to prevent fluid flow from the other side. The backup valve 21b overlaps the valve seat member side of leaf valve 21a. When valve body 21 seats on annular valve seat 20e, it abuts against the valve seat side of leaf valve 21a, supporting it. This restrains the upward deflection of the portion between annular valve seat 20e and inner circumferential seat portion 20f of leaf valve 21a, which is subject to downward pressure. In this way, the backup valve 21b supports the leaf valve 21a, and when the valve body 21 is seated on the annular valve seat 20e, the leaf valve 21a is suppressed from being greatly bent toward the valve seat member side, thereby preventing excessive stress from acting on the leaf valve 21a and protecting the leaf valve 21a.

[0044] Furthermore, the extension-side auxiliary valve EV allows liquid to flow from the lower side to the upper side through the port 20c before the valve body 21 flexes toward the valve seat member and seats on the annular valve seat 20e. When used as a check valve, the amount of flexure of the valve body 21 when it abuts the annular valve seat 20e can be adjusted by setting the height of the seat surface between the inner circumferential seat portion 20f and the annular valve seat 20e. This flexure can also be adjusted by interposing a gasket between the inner circumferential seat portion 20f and the valve body 21. If a gasket is used, the seat surface height of the inner circumferential seat portion 20f should be set lower than the seat surface height of the annular valve seat 20e. The amount of flexure can be adjusted by adjusting the number of gaskets stacked.

[0045] The valve stopper 23 is stacked on the side of the gasket 22 opposite to the valve seat component. If the valve body 21 is greatly bent, it will abut against at least one of the annular plates 21a1, 21a2, and 21a3 of the valve body 21 and support the valve body 21, thereby preventing excessive stress from acting on the valve body 21 and protecting the valve body 21.

[0046] Valve stopper 23 Figure 2 The liner 24 is stacked in the middle and lower part. The liner 24 is formed into a bottomed cylindrical shape, and the bottom is provided with a hole 24a that allows the small diameter portion 2a of the rod 2 to be inserted through, and a cutout 24c that connects the inside and the outside is provided on the cylindrical portion 24b, and the opening side is facing the Figure 2The lower center portion is fixed to the outer circumference of the small-diameter portion 2a of the rod 2. Furthermore, the cylindrical portion 24b is radially opposed to the through-holes 2e and 2f provided in the small-diameter portion 2a, so that the interior of the cylindrical portion 24b communicates with the interior of the rod 2. Furthermore, the gasket 24 is disposed on the side of the valve body 21 opposite the valve seat member. Therefore, the upper end of the gasket 24 can be used as a valve stopper, eliminating the need for the valve stopper 23.

[0047] The partition member 25 is a bottomed cylindrical member with a hole 25a on the bottom thereof for allowing the small diameter portion 2a of the rod 2 to pass therethrough, and the opening side thereof is directed upward to align with the spacer 24. Figure 2 The lower end of the valve seat member 20 overlaps with the lower end of the valve seat member 20, while the cylindrical portion fits into the outer circumference of the valve seat member 20 and is fixed to the outer circumference of the small-diameter portion 2a of the rod 2. The outer diameter of the partition member 25 is smaller than the inner diameter of the cylinder 1, forming an annular gap between it and the cylinder 1. Together with the valve seat member 20, it separates the space R3 within the expansion-side chamber R1. Space R3 communicates with the expansion-side chamber R1 via the port 20c provided on the valve seat member 20, and with the compression-side chamber R2 via the notch 24c of the gasket 24, the through-holes 2e and 2f in the small-diameter portion 2a, and the interior of the rod 2. Furthermore, the port 20c, space R3, through-holes 2e and 2f, and the interior of the rod 2 form an expansion-side secondary passage EP, which serves as a damping passage connecting the expansion-side chamber R1 and the compression-side chamber R2. This thus constructed expansion-side secondary passage EP is connected in parallel with the expansion-side passage 3a provided on the piston 3, connecting the expansion-side chamber R1 and the compression-side chamber R2. Therefore, the expansion-side sub-valve EV is provided on the expansion-side sub-passage EP, and the expansion-side sub-passage communicates the expansion-side chamber R1 and the contraction-side chamber R2 while bypassing the expansion-side passage 3a.

[0048] In this embodiment, the compression side auxiliary valve CV used as a damping valve is as follows: Figure 2 As shown, the sub-valve CV is disposed between the partition member 25 and the compression-side main valve 5 and is attached to the outer periphery of the small-diameter portion 2a. Specifically, the sub-valve CV includes a valve seat member 26, a valve body 27, and a gasket 28.

[0049] The valve seat member 26 is annular and comprises: a disc-shaped partition 26a having an opening, which is fitted on the outer periphery of the small diameter portion 2a; an annular seat portion 26b which is oppositely arranged from the partition 26a. Figure 2 The outer periphery of the lower end protrudes downward; annular groove 26c, which is provided on the inner periphery of the separator 26a; a plurality of ports 26d, which are larger than the separator 26a Figure 2 The lower end of the relative seat portion 26b is closer to the inner peripheral side opening and communicates with the annular groove 26c; the window 26e of the annular recess is located at the separator 26a. Figure 2 The lower end of the valve seat 26a is connected to the outlet end of each port 26d; the annular valve seat 26f is arranged to be located at the separator 26a Figure 2an annular inner peripheral seat portion 26g, which is provided on the inner peripheral portion of the window 26e; a plurality of limiting portions 26h, which protrude axially from the window 26e of the separator 26a.

[0050] The opposing seat portion 26b surrounds the outer circumference of the annular valve seat 26f and protrudes downward further than the lower end of the annular valve seat 26f. Specifically, as viewed from the partition 26a, the opposing seat portion 26b is higher than the annular valve seat 26f. The height difference between the opposing seat portion 26b and the annular valve seat 26f is at least greater than the combined axial thickness of the backup valve 27b and the annular plate 27a1 of the leaf valve 27a of the valve body 27, described below. Furthermore, in this embodiment, since the inner circumference of the valve body 27 serves as the fixed end and the outer circumference serves as the free end, the annular valve seat 26f is radially located on the fixed end side (inner circumference side) of the valve seat member 26 relative to the opposing seat portion 26b.

[0051] In addition, in this embodiment, the relatively set seat portion 26b and the annular valve seat 26f are an integral whole relative to the partition body 26a and protrude axially, and the annular valve seat 26f is connected to the inner side of the relatively set seat portion 26b. However, when the inner peripheral side of the valve body 27 is a fixed end, on the inner peripheral side of the relatively set seat portion 26b, the annular valve seat 26f can be separated from the relatively set seat portion 26b and protrude from the partition body 26a.

[0052] The inner peripheral seat portion 26g is a seat portion that contacts the fixed end side of the valve body 21 and is formed from the inner peripheral seat portion 26g of the partition body 26a. Figure 2 The inner peripheral side of the window 26e at the lower end protrudes downward and is axially opposed to the valve body 27. The lower end is provided with an annular seat surface 26g1 that abuts against the fixed end side (inner peripheral portion) of the valve body 27. Figure 3As shown in Figure (B), the seat surface 26g1 includes an inclined surface 26g2 on its outer periphery, which slopes away from the valve body 27 from the fixed end toward the free end. In this case, the inner periphery of the valve body 27 is the fixed end, while the outer periphery of the valve body 27 is the free end. Therefore, when viewed from the partition 26a, the inner periphery of the inclined surface 26g2 of the inner periphery seat portion 26g is higher than the outer periphery. Overall, the inclined surface 26g2 slopes further away from the valve body 27 on the outer periphery than on the inner periphery. Furthermore, the inner periphery of the inclined surface 26g2 of the seat surface 26g1 is horizontal, and when the valve body 27 is mounted on the small-diameter portion 2a of the rod 2, it, together with the gasket 28, holds the inner periphery of the valve body 21. The inclined surface 26g2 smoothly connects to the horizontal surface, ensuring that the slope does not change sharply at the interface between the inclined surface 26g2 of the seat surface 26g1 and the horizontal surface on the inner periphery of the inclined surface 26g2. In addition, in this embodiment, the inclined surface 26g2 of the seat surface 26g1 is a tapered inclined surface, but it can also be a curved surface. Figure 3 (B) The height of the horizontal plane at the lower end is higher than that of the annular valve seat 26f. Figure 2 The height of the middle and lower end surface (seat surface) is lower than the relatively set seat portion 26b.

[0053] Furthermore, in the compression-side auxiliary valve CV, the valve seat member 26 includes a plurality of restricting portions 26h at the lower end of the partition body 26a. These restricting portions 26h protrude axially from the fixed end side (inner circumference) of the valve body 27, radially closer to the annular valve seat 26f. In this embodiment, the restricting portions 26h are provided between the annular valve seat 26f and the inner circumferential seat portion 26g, and between the ports 26d and 26d within the window 26e in the circumferential direction of the partition body 26a. However, the location of the restricting portions 26h between the annular valve seat 26f and the inner circumferential seat portion 26g can be designed and modified as desired, as long as they do not interfere with the ports 26d. Furthermore, the shape of the restricting portions 26h of the valve seat member 26, when viewed axially, can be either arcuate or circular, and can be designed and modified as desired. Furthermore, the restricting portions 26h are provided at positions avoiding the port 26d and between the ports 26d and 26d in the circumferential direction of the partition body 26a. When the valve body 27 flexes toward the valve seat member, the restricting portions 26h uniformly support the valve body 27 in the circumferential direction. Therefore, they are preferably provided at equal intervals on the same circumference. However, they may be provided at unequal intervals on the same circumference as long as they can support the valve body 27. Furthermore, although the seat surface height of the restricting portions 26h is the same as that of the annular valve seat 26f, the valve body 27 may be provided lower than the annular valve seat 26f as long as it abuts against the backup valve 27b when seated on the annular valve seat 26f and can support the valve body 27.

[0054] like Figure 2As shown, the valve body 27 is composed of a leaf valve 27a, which is composed of multiple annular plates, the inner peripheral side of which is fixed to the small diameter portion 2a and serves as a fixed end, and the outer peripheral side that allows flexibility serves as a free end; and a backup valve 27b, which is stacked on the valve seat member side of the leaf valve 27a. This valve body is stacked on the partition 26a of the valve seat member 26. Figure 2 The lower end of the small diameter portion 2a is fixed to the outer periphery of the small diameter portion 2a.

[0055] The leaf valve 27a is composed of three elastic annular plates 27a1, 27a2, and 27a3. The inner diameters of the three plates are all set to fit into the outer periphery of the small diameter portion 2a. Figure 2 The annular plate 27a1 at the top and with the largest outer diameter and elasticity, the annular plate 27a2 with an outer diameter smaller than the annular plate 27a1 and stacked on the side of the annular plate 27a1 opposite to the valve seat component, and the annular plate 27a3 with an outer diameter smaller than the annular plate 27a2 and stacked on the side of the annular plate 27a2 opposite to the valve seat component.

[0056] In addition, the backup valve 27b is stacked on the annular plate 27a1 having the largest outer diameter of the leaf valve 27a. Figure 2 The upper portion (valve seat member side) of the annular plate 27a1 has an outer diameter smaller than that of the annular plate 27a1 and the annular valve seat 26f, and an inner diameter equal to that of the annular plate 27a1. Furthermore, in this case, the outer diameter of the backup valve 27b is smaller than the inner diameter of the seat surface at the lower end of the annular valve seat 26f. Therefore, even if the valve body 27 deflects toward the valve seat member, it is the annular plate 27a1 of the leaf valve 27a that seats on the annular valve seat 26f.

[0057] Furthermore, when the valve body 27 of this structure is overlapped with the inner circumferential seat portion 26g of the partition 26a of the valve seat member 26, since the inner circumferential seat portion 26g is higher than the annular valve seat 26f, the valve body 27 and the annular valve seat 26f are axially opposed to each other, and a gap is formed in the axial direction between the backup valve 27b and the annular valve seat 26f. Furthermore, the outer circumferential surface of the free end of the annular plate 27a1 having the largest outer diameter of the leaf valve 27a is radially opposed to the inner circumferential surface of the opposing seat portion 26b of the valve seat member 26, with a slight gap therebetween. When the leaf valve 27a is facing the opposing seat portion 26b, the gap between the leaf valve 27a and the opposing seat portion 26b is extremely small, making it difficult for liquid to pass through this gap. This state is considered the closed state of the compression-side auxiliary valve CV. In addition, if at least a portion of the outer peripheral surface of the free end side of the valve body 27 is radially opposite to the relatively set seat portion 26b, the compression side auxiliary valve CV can open or close the port 26d. Therefore, the entire outer peripheral surface of the annular plate 27a1 does not need to be radially opposite to the entire inner peripheral surface of the relatively set seat portion 26b.

[0058] The outer diameter of the gasket 28 stacked on the side of the valve body 27 opposite to the valve seat member is smaller than the outer diameter of the annular plate 27a3 disposed on the side of the leaf valve 27a opposite to the valve seat member and farthest from the valve seat member, and the inner diameter of the inclined surface 26g2 on the seat surface 26g1 of the inner peripheral seat portion 26g. The gasket is fixed to the small diameter portion 2a in an immovable manner. In addition, although the gasket 28 is composed of a single annular plate, it can also be composed of multiple annular plates. Therefore, the leaf valve 27a and the backup valve 27b of the valve body 27 are subjected to the pressure from the valve seat member 26. Figure 2 When the pressure of the liquid passes through the port 26d downward, the outer peripheral edge of the gasket 28 is used as a fulcrum to move the outer peripheral side. Figure 2 The leaf valve 27a deflects downwardly and radially. As a result, the outer circumference of the leaf valve 27a no longer directly faces the inner circumference of the opposing seat 26b, but instead deviates downward relative to the opposing seat 26b. The area of ​​the flow path formed by the gap between the leaf valve 27a and the opposing seat 26b increases as the deflection of the leaf valve 27a increases. Thus, when the leaf valve 27a deviates from its direct alignment with the opposing seat 26b, the compression-side auxiliary valve CV opens. The compression-side auxiliary valve CV, through the valve body 27, allows liquid to flow through the gap while also applying resistance to the flow of liquid.

[0059] Furthermore, when the leaf valve 27a and the backup valve 27b of the valve body 27 are subjected to the pressure from the valve seat member 26, Figure 3 (B) When the pressure of the liquid passes through the port 26d upward, the outer peripheral side is moved toward the inner peripheral edge of the inclined surface 26g2 of the seat surface 26g1 of the inner peripheral seat portion 26g of the valve seat member 26. Figure 3 (B) When the valve body 27 deflects by a predetermined amount or more, the annular plate 27a1 of the leaf valve 27a is seated on the annular valve seat 26f, thereby closing the port 26d.

[0060] If the entire seat surface 26g1 of the inner circumferential seat portion 26g is horizontal, the valve body 27 will bend and deform at the fulcrum of the flexure when the free end of the valve body 27 flexes toward the valve seat member. Conversely, by providing the seat surface 26g1 of the inner circumferential seat portion 26g, which serves as the seat portion, with the inclined surface 26g2, the inner circumference of the valve body 27 can deform along the inclined surface 26g2, thereby reducing the bending deformation at the fulcrum of the flexure. Furthermore, by positioning the fulcrum of the flexure of the inner circumference of the valve body 27 closer to the inner circumference, the radial length of the flexible portion of the valve body 27 that is not fixed is increased, thereby reducing the amount of deformation of the inner circumference of the valve body 27. This can reduce the stress acting on the inner circumference of the valve body 27 when the valve body 27 flexes toward the valve seat member. In addition, the radial length of the flexible portion of the valve body 27 that is not fixed becomes longer. When the valve body 27 is bent toward the valve seat member, the annular valve seat 26f of the valve body 27 is Figure 3(B) The slope of the lower end surface decreases, making it easier for the valve body 27 to hit the lower end surface of the annular valve seat 26f, and the valve body 27 is tightly fitted to the lower end surface as a whole.

[0061] In this way, the compression side auxiliary valve CV, which serves as a damping valve, Figure 2 When the liquid flows downward through the port 26d, the free end of the valve body 27 bends toward the side opposite to the valve seat member to open the valve and allow the liquid to flow. Figure 2 When fluid flows upward through port 26d, the free end of valve body 27 deflects toward the valve seat member and seats on annular valve seat 26f, thereby blocking the flow of fluid. This allows the compression-side auxiliary valve CV to function as a damping valve, opening the valve to allow fluid flow through port 26d from one side and applying resistance to the fluid. Conversely, it also functions as a check valve, closing the valve to block fluid flow through port 26d from the other side. The backup valve 27b overlaps the valve seat member side of leaf valve 27a. When leaf valve 27a seats on annular valve seat 26f, it abuts against the valve seat side of leaf valve 27a, supporting it. This restrains the upward deflection of the portion of leaf valve 27a between annular valve seat 26f and inner circumferential seat portion 26g, which is subject to downward pressure. In this way, the backup valve 27b supports the leaf valve 27a, and when the valve body 27 is seated on the annular valve seat 26f, the leaf valve 27a is restrained from significantly deflecting toward the valve seat member. This prevents excessive stress from acting on the leaf valve 27a, thereby protecting the leaf valve 27a. Furthermore, the valve seat member 26 of the compression-side auxiliary valve CV, in addition to the structure of the expansion-side auxiliary valve EV, further includes a restricting portion 26h. This restricting portion abuts the backup valve 27b when the portion intermediate between the portion contacting the annular valve seat 26f of the valve body 27 and the portion contacting the inner circumferential seat portion 26g deflects by a predetermined amount or more. This restricting portion supports the backup valve 27b from the valve seat member side, thereby restricting deflection between the annular valve seat 26f of the valve body 27 and the fixed end. Therefore, in the compression-side auxiliary valve CV, not only the backup valve 27b but also the restricting portion 26h can suppress deflection of the intermediate portion of the leaf valve 27a, thereby further reducing fatigue on the leaf valve 27a. Furthermore, the heights of the restricting portion 26h and the annular valve seat 26f need only be set so that the restricting portion 26h does not prevent the valve body 27 from unseating and seating on the annular valve seat 26f. Within this limit, the amount of deflection of the valve body 27 when it abuts the restricting portion 26h, i.e., the predetermined amount, can be set arbitrarily. However, the predetermined amount should be set to ensure that the valve body 27 is supported by the restricting portion 26h before excessive stress on the valve body 27 becomes excessive.

[0062] Furthermore, the compression-side sub-valve CV allows liquid to flow from the lower side to the upper side through port 26d before the valve body 27 flexes toward the valve seat member and seats on the annular valve seat 26f. When used as a check valve, the amount of flexure of the valve body 27 when it abuts the annular valve seat 26f can be adjusted by setting the height of the seat surface between the inner circumferential seat portion 26g and the annular valve seat 26f. This flexure can also be adjusted by interposing a gasket between the inner circumferential seat portion 26g and the valve body 27. If a gasket is used, the seat surface height of the inner circumferential seat portion 26g is set lower than the seat surface height of the annular valve seat 26f. The amount of flexure can be adjusted by adjusting the number of gaskets stacked.

[0063] The valve stopper 29 is stacked on the side of the gasket 28 opposite to the valve seat component. When the valve body 27 is greatly deflected, it abuts against at least one of the annular plates 27a1, 27a2, and 27a3 of the valve body 27 and supports the valve body 27, thereby preventing excessive stress from acting on the valve body 27 and protecting the valve body 27.

[0064] When the compression-side auxiliary valve CV of this structure is stacked on the outer circumference of the small-diameter portion 2a, below the gasket 24, the annular groove 26c formed on the inner circumference of the valve seat member 26 radially opposes the through-holes 2g and 2h provided in the small-diameter portion 2a. Consequently, the port 26d communicates with the interior of the rod 2. Consequently, the expansion-side chamber R1 communicates with the compression-side chamber R2 via the port 26d, through-holes 2g and 2h, and the interior of the rod 2. Furthermore, the port 26d, through-holes 2g and 2h, and the interior of the rod 2 form a compression-side auxiliary passage CP, serving as a damping passage connecting the expansion-side chamber R1 and the compression-side chamber R2. This compression-side auxiliary passage CP, thus constructed, is connected in parallel with the compression-side passage 3b provided in the piston 3, connecting the expansion-side chamber R1 and the compression-side chamber R2. Therefore, the compression-side sub-valve CV is provided on the compression-side sub-passage CP, and the compression-side sub-passage communicates between the expansion-side chamber R1 and the compression-side chamber R2 while bypassing the compression-side passage 3b.

[0065] Furthermore, a cylindrical rotary valve 12 is housed within the rod 2. This cylindrical rotary valve has an outer circumferential surface in sliding contact with the inner circumferential surface of the rod 2, allowing it to rotate circumferentially within the rod 2. Rotary valve 12 has holes 12a, 12b, 12c, and 12d, respectively, at positions corresponding to through-holes 2e, 2f, 2g, and 2h, connecting the inside and the outside. Rotating rotary valve 12 via a control rod 13 inserted within the rod 2 not only changes the degree of communication between through-hole 2e and hole 12a, through-hole 2f and hole 12b, through-hole 2g and hole 12c, and through-hole 2h and hole 12d, but also allows through-holes 2e, 2f, 2g, and 2h to be offset from holes 12a, 12b, 12c, and 12d, thereby blocking them. Specifically, rotary valve 12 can adjust the areas of the four flow paths defined by through-hole 2e and hole 12a, through-hole 2f and hole 12b, through-hole 2g and hole 12c, and through-hole 2h and hole 12d, respectively, based on its rotational position relative to the circumferential direction of rod 2, thereby adjusting the resistance exerted on the flow of hydraulic oil through these flow paths. Furthermore, in this embodiment, control rod 13 is driven by a rotary actuator (not shown), such as a stepping motor, mounted at the distal end of rod 2. The rotary actuator can be housed within rod 2.

[0066] Furthermore, when the rotary valve 12 is in a state where the through-holes 2e and 2f are connected to the corresponding holes 12a and 12b, respectively, the expansion-side chamber R1 and the compression-side chamber R2 are connected via the expansion-side sub-passage EP. Furthermore, when the rotary valve 12 is in a state where the through-holes 2g and 2h are connected to the corresponding holes 12c and 12d, respectively, the expansion-side chamber R1 and the compression-side chamber R2 are connected via the compression-side sub-passage CP. Thus, the rotary valve 12 is disposed midway between the expansion-side sub-passage EP and the compression-side sub-passage CP. Rotating the control rod 13 can change the degree of connection (flow path area) between the holes 12a, 12b, 12c, and 12d and the corresponding through-holes 2e, 2f, 2g, and 2h, respectively, thereby varying the resistance applied to the flow of liquid through the expansion-side sub-passage EP and the compression-side sub-passage CP. The rotary valve 12 also includes two holes 12a and 12b for adjusting the flow area of ​​the extension-side auxiliary passage EP, and two holes 12c and 12d for adjusting the flow area of ​​the compression-side auxiliary passage CP. However, the number of holes provided can be arbitrarily changed based on the maximum flow area. Furthermore, the number of through-holes provided in the rod 2 can be set based on the number of holes provided in the rotary valve 12. Furthermore, the holes 12a, 12b, 12c, and 12d provided in the rotary valve 12 can be staggered in the circumferential direction, as long as the through-holes 2e, 2f, 2g, and 2h provided in the rod 2 are positioned to correspond to the holes 12a, 12b, 12c, and 12d and are appropriately positioned. In addition, according to the damping force characteristics required by the buffer D, when the hole 12a and the through hole 2e arranged in the middle of the extension side sub-channel EP are opposite to each other and connected to each other, the hole 12b and the through hole 2f can be connected, or the timing when the hole 12a and the through hole 2e are opposite to each other can be staggered with the timing when the hole 12b and the through hole 2f are opposite to each other. This setting method is also applicable to the relationship between the holes 12c, 12d and the through holes 2g, 2h arranged in the middle of the compression side sub-channel CP.

[0067] The expansion-side auxiliary valve EV and the compression-side auxiliary valve CV and the shock absorber D functioning as the damping valve are configured in this manner. Next, operations of the expansion-side auxiliary valve EV and the compression-side auxiliary valve CV and the shock absorber D functioning as the damping valve will be described.

[0068] First, when the buffer D extends, the piston 3 moves in the cylinder 1 toward Figure 1, compressing the expansion-side chamber R1. When the expansion-side sub-channel EP and the compression-side sub-channel CP are connected by the rotary valve 12, the liquid in the expansion-side chamber R1, compressed by the upward movement of the piston 3, attempts to move toward the expanded compression-side chamber R2 through the expansion-side channel 3a and the expansion-side sub-channel EP provided on the piston 3. At this time, when the expansion speed of the damper D is within the slightly low speed range and close to zero, although the pressure in the expansion-side chamber R1 rises, the differential pressure between the pressure in the expansion-side chamber R1 and the pressure in the compression-side chamber R2 does not reach the valve-opening pressure of the expansion-side main valve 4. Therefore, the expansion-side main valve 4 does not open, but maintains the expansion-side channel 3a closed. The compression-side main valve 5, receiving pressure from the expansion-side chamber R1 from the back, closes the compression-side channel 3b.

[0069] When the piston speed of the buffer D is close to zero during the extension action, although the pressure in the extension side chamber R1 rises, the differential pressure between it and the pressure in the compression side chamber R2 does not reach the valve opening pressure of the valve body 21 of the extension side auxiliary valve EV. Therefore, even if the valve body 21 is bent, the outer peripheral surface of the annular plate 21a1 of the leaf valve 21a is opposite to the axial width range of the inner periphery of the relatively set seat portion 20b, and the valve is in a closed state, the flow path area of ​​the annular gap between the valve body 21 and the relatively set seat portion 20b is maintained at an extremely small state.

[0070] On the other hand, when the expansion speed of the damper D is within the slightly slow speed range and near zero, despite the pressure rise in the expansion-side chamber R1, the pressure differential between the expansion-side chamber R1 and the compression-side chamber R2 is small, and the valve body 27 of the compression-side sub-valve CV does not flex toward the valve seat member until it seats on the annular valve seat 26f. Thus, when the expansion speed of the damper D is within the slightly slow speed range and near zero, the valve body 27 maintains the closed valve position by aligning the outer circumferential surface of the annular plate 27a1 of the leaf valve 27a with the axial width of the inner circumference of the opposing seat portion 26b. This maintains the flow path area of ​​the annular gap between the valve body 27 and the opposing seat portion 26b at a minimum.

[0071] Therefore, when the expansion speed of the shock absorber D is within the slightly low speed range and approaches zero, the expansion-side auxiliary valve EV and the compression-side auxiliary valve CV are in the closed state, making it difficult for the liquid in the expansion-side chamber R1 to pass through the expansion-side auxiliary passage EP and the compression-side auxiliary passage CP. In addition, the expansion-side main valve 4 also closes the expansion-side passage 3a. Therefore, when the expansion speed of the shock absorber D is within the slightly low speed range and approaches zero, the characteristics of the damping force generated by the piston speed of the shock absorber D (damping force characteristics) increase sharply, as shown in FIG. Figure 4 shown.

[0072] Furthermore, when the piston speed of the buffer D increases during the extension operation and changes from the slightly low speed range to the low speed range, the pressure difference between the pressure of the extension side chamber R1 and the pressure of the compression side chamber R2 exceeds the valve opening pressure of the valve body 21. Therefore, the valve body 21 moves its outer periphery from the range of the axial width relative to the inner periphery of the seat portion 20b to the inner periphery of the seat portion 20b. Figure 2 The lower center portion of the valve body 21 deflects and opens the valve, increasing the flow path area of ​​the annular gap between the valve body 21 and the opposing seat portion 20b. Consequently, liquid can flow from the expansion-side chamber R1 to the compression-side chamber R2 via the expansion-side auxiliary valve EV and the expansion-side auxiliary passage EP. Meanwhile, when the piston speed of the damper D increases during its extension operation, shifting from the slightly low speed range to the low speed range, the valve body 27 of the compression-side auxiliary valve CV is deflected by the pressure within the expansion-side chamber R1, seating on the annular valve seat 26f of the valve seat member 26. This seals the port 26d and prevents liquid from flowing through the compression-side auxiliary passage CP.

[0073] Therefore, when the piston speed of the buffer D increases during the extension action and changes from the slightly low speed range to the low speed range, the flow path area of ​​the extension side auxiliary valve EV increases as the piston speed increases. Therefore, the damping force characteristics of the buffer D are as follows: Figure 4 As shown, the slope of its characteristic curve is smaller than the damping force characteristic curve in the micro-low speed range.

[0074] Furthermore, when the piston speed of the buffer D increases and exceeds the low-speed range during its extension action, the valve body 21 bends significantly and abuts against the valve stopper 23, thereby maximizing the flow path area of ​​the annular gap between it and the relatively set seat portion 20b. On the other hand, the extension-side main valve 4 bends away from the piston 3, causing the extension-side channel 3a to open. As a result, the liquid moves from the extension-side chamber R1 to the compression-side chamber R2 through the gap between the extension-side main valve 4 and the piston 3. As the piston speed increases, the deflection of the extension-side main valve 4 increases, and the flow path area of ​​the gap between the extension-side main valve 4 and the piston 3 becomes larger than the flow path area of ​​the annular gap between the valve body 21 of the extension-side auxiliary valve EV and the relatively set seat portion 20b. Therefore, the buffer D mainly generates damping force through the resistance to the flow of the liquid applied by the extension-side main valve 4. Therefore, when the piston speed of the buffer D increases and exceeds the low-speed range during its extension action, as the piston speed increases, the damping force characteristics of the buffer D change as shown in FIG. Figure 4 As shown, the damping force is generated with a nearly constant slope relative to the increase in piston speed. In addition, the resistance applied to the flow of the liquid through the extension-side auxiliary channel EP can be adjusted by rotating the rotary valve 12. Therefore, in the shock absorber D of this embodiment, the magnitude of the damping force can be adjusted. In addition, when the shock absorber D is extended, the rod 2 will withdraw from the cylinder 1, and the free piston 11 will move toward the cylinder 1. Figure 2The movement in the middle and upper part causes the gas chamber G to expand to compensate for the volume generated by the rod 2 withdrawing from the inside of the cylinder 1.

[0075] Thus, when the piston speed of the buffer D increases and exceeds the low speed range during the extension operation, the pressure in the extension side chamber R1 will greatly exceed the pressure in the compression side chamber R2. Figure 2 The pressure in the extension side chamber R1 acting on the valve body 27 and the pressure from the valve body 27 through the port 26d are Figure 2 The pressure difference in the compression side chamber R2 acting from the middle and upper part becomes larger. In this case, the leaf valve 27a of the valve body 27 in the compression side auxiliary valve CV is pressed upward by the pressure from the expansion side chamber R1. However, since the outer peripheral side of the leaf valve 27a is supported by the annular valve seat 26f and the inner peripheral side is supported by the inner peripheral seat portion 26g, the middle part between the part contacting the annular valve seat 26f of the leaf valve 27a and the part contacting the inner peripheral seat portion 26g is pushed upward. Figure 2 The backup valve 27b abuts the valve seat member side of the leaf valve 27a, supporting the leaf valve 27a and suppressing deflection of the middle portion of the leaf valve 27a. This prevents the middle portion of the leaf valve 27a from deflecting and protruding upward, reducing the stress acting on the leaf valve 27a and suppressing fatigue of the leaf valve 27a. Furthermore, when the valve body 27 is pressed by the pressure in the expansion-side chamber R1 and the backup valve 27b abuts the restriction portion 26h of the valve seat member 26, it is supported by the restriction portion 26h, preventing further deflection of the middle portion of the leaf valve 27a. This prevents further stress on the leaf valve 27a and further suppresses fatigue of the leaf valve 27a.

[0076] Next, when the buffer D contracts, the piston 3 moves in the cylinder 1 toward Figure 1 The piston 3 moves downward in the compression-side chamber R2 and compresses the compression-side chamber R2. When the extension-side sub-channel EP and the compression-side sub-channel CP are connected by the rotary valve 12, the liquid in the compression-side chamber R2, which has been compressed by the downward movement of the piston 3, attempts to move toward the expanded extension-side chamber R1 through the compression-side channel 3b and the compression-side sub-channel CP provided on the piston 3. When the contraction speed of the shock absorber D is within the slightly low speed range and close to zero, although the pressure in the compression-side chamber R2 rises, the pressure difference between the pressure in the compression-side chamber R2 and the pressure in the extension-side chamber R1 does not reach the valve opening pressure of the compression-side main valve 5. Therefore, the compression-side main valve 5 does not open and maintains the compression-side channel 3b closed. The extension-side main valve 4 receives pressure from the compression-side chamber R2 from the back, thereby closing the extension-side channel 3a.

[0077] When the piston speed of the buffer D is close to zero during the contraction action, although the pressure in the compression side chamber R2 rises, the pressure difference between it and the pressure in the extension side chamber R1 does not reach the valve opening pressure of the valve body 27 in the compression side auxiliary valve CV. Therefore, even if the valve body 27 is bent, the outer peripheral surface of the annular plate 27a1 of the leaf valve 27a is opposite to the axial width range of the inner periphery of the relatively set seat portion 26b, and the valve is closed, thereby maintaining the flow path area of ​​the annular gap between the valve body 27 and the relatively set seat portion 26b at an extremely small state.

[0078] On the other hand, when the contraction speed of the damper D is within the slightly slow speed range and near zero, although the pressure in the contraction-side chamber R2 rises, the pressure differential between the contraction-side chamber R2 and the expansion-side chamber R1 is small, so the valve body 21 of the expansion-side sub-valve EV does not flex toward the valve seat member until it seats on the annular valve seat 20e. Thus, when the contraction speed of the damper D is within the slightly slow speed range and near zero, the valve body 21 maintains the closed valve position by keeping the outer circumferential surface of the annular plate 21a1 of the leaf valve 21a aligned with the inner circumference of the opposing seat portion 20b within the axial width. This keeps the flow path area of ​​the annular gap between the valve body 21 and the opposing seat portion 20b extremely small.

[0079] Therefore, when the contraction speed of the shock absorber D is within the slightly low speed range and close to zero, the extension-side auxiliary valve EV and the compression-side auxiliary valve CV are in the closed state, making it difficult for the liquid in the extension-side chamber R1 to pass through the extension-side auxiliary channel EP and the compression-side auxiliary channel CP. In addition, the compression-side main valve 5 also closes the compression-side channel 3b. Therefore, when the contraction speed of the shock absorber D is within the slightly low speed range and close to zero, the characteristics of the damping force generated by the piston speed of the shock absorber D (damping force characteristics) increase sharply, as shown in FIG. Figure 4 shown.

[0080] Furthermore, when the piston speed of the shock absorber D increases during the contraction operation and changes from the slightly low speed range to the low speed range, the pressure difference between the pressure of the compression side chamber R2 and the pressure of the expansion side chamber R1 exceeds the valve opening pressure of the valve body 27. Therefore, the valve body 27 expands its outer periphery from the range of the axial width relative to the inner periphery of the seat portion 26b to the inner periphery of the seat portion 26b. Figure 2 The lower center portion of the valve body 27 deflects and opens the valve, increasing the flow path area of ​​the annular gap between the valve body 27 and the opposing seat portion 26b. This allows liquid to flow through the compression-side auxiliary valve CV and, via the compression-side auxiliary passage CP, from the compression-side chamber R2 to the expansion-side chamber R1. Meanwhile, when the piston speed of the damper D increases during contraction, shifting from the slightly slow speed range to the slow speed range, the valve body 21 of the expansion-side auxiliary valve EV deflects in response to the pressure within the compression-side chamber R2, seating on the annular valve seat 20e in the valve seat member 20. This seals the port 20c and prevents liquid from flowing through the expansion-side auxiliary passage EP.

[0081] Therefore, when the piston speed of the shock absorber D increases during the contraction operation and changes from the slightly low speed range to the low speed range, the flow path area of ​​the compression side auxiliary valve CV increases as the piston speed increases. Therefore, the damping force characteristics of the shock absorber D are as follows: Figure 4 As shown, the slope of its characteristic curve is smaller than the damping force characteristic curve in the micro-low speed range.

[0082] Furthermore, when the piston speed of the buffer D increases and exceeds the low-speed range during its contraction, the valve body 27 bends significantly and abuts against the valve stopper 29, thereby maximizing the flow path area of ​​the annular gap between it and the relatively set seat portion 26b. On the other hand, the compression-side main valve 5 bends away from the piston 3, causing the compression-side channel 3b to open. As a result, the liquid moves from the compression-side chamber R2 to the extension-side chamber R1 through the gap between the compression-side main valve 5 and the piston 3. As the piston speed increases, the deflection of the compression-side main valve 5 increases, and the flow path area of ​​the gap between the compression-side main valve 5 and the piston 3 becomes larger than the flow path area of ​​the annular gap between the valve body 27 of the compression-side auxiliary valve CV and the relatively set seat portion 26b. Therefore, the buffer D mainly generates damping force through the resistance exerted on the flow of liquid by the compression-side main valve 5. Therefore, when the piston speed of the buffer D increases and exceeds the low-speed range during its contraction, as the piston speed increases, the damping force characteristics of the buffer D change as follows: Figure 4 As shown, the damping force has a nearly constant slope with respect to the increase in piston speed. In addition, the resistance applied to the flow of the liquid through the compression-side auxiliary channel CP can be adjusted by rotating the rotary valve 12. Therefore, in the shock absorber D of this embodiment, the magnitude of the damping force can be adjusted. In addition, when the shock absorber D is contracting, the rod 2 enters the cylinder 1, and the free piston 11 moves toward the cylinder 1. Figure 2 The movement in the middle and lower part reduces the gas chamber G to compensate for the volume of the rod 2 entering the cylinder 1.

[0083] Thus, when the piston speed of the shock absorber D increases and exceeds the low speed range during the contraction operation, the pressure in the compression side chamber R2 will greatly exceed the pressure in the expansion side chamber R1. Figure 2 The pressure in the compression chamber R2 of the valve body 21 acts on the pressure in the middle and lower part of the valve body 21 and the pressure in the compression chamber R2 acts on the pressure in the compression chamber R2 of the valve body 21 through the port 20c. Figure 2 The pressure difference in the expansion side chamber R1 acting from the middle and upper part becomes larger. In this case, the leaf valve 21a of the valve body 21 in the expansion side auxiliary valve EV is pressed upward by the pressure in the compression side chamber R2. However, since the outer peripheral side of the leaf valve 21a is supported by the annular valve seat 20e and the inner peripheral side is supported by the inner peripheral seat 20f, the middle part between the part contacting the annular valve seat 20e of the leaf valve 21a and the part contacting the inner peripheral seat 20f is pushed upward. Figure 2The backup valve 21b abuts against the valve seat member side of the leaf valve 21a and supports the leaf valve 21a, thereby suppressing the deflection of the middle portion of the leaf valve 21a. Therefore, it is possible to suppress the middle portion of the leaf valve 21a from deflecting and protruding upward, reduce the stress acting on the leaf valve 21a, and suppress fatigue of the leaf valve 21a.

[0084] As described above, the expansion-side sub-valve EV and the compression-side sub-valve CV serving as the damping valves according to the present embodiment include the annular valve bodies 21 and 27 and the valve seat members 20 and 26 . Among them, the inner circumference of the annular valve body 21, 27 is a fixed end and the outer circumference is a free end, allowing the free end to flex relative to the fixed end; the valve seat components 20, 26 have: annular relatively arranged seat portions 20b, 26b, which are annular and opposite to at least a portion of the circumferential surface on the free end side of the valve body 21, 27; ports 20c, 26d, which are arranged radially closer to the fixed end side of the valve body 21, 27 than the relatively arranged seat portions 20b, 26b; annular valve seats 20e, 26f, which are arranged between the relatively arranged seat portions 20b, 26b and the ports 20c, 26d and axially opposite to the valve body 21, 27, and can allow the valve body 21, 27 to move from the seat and sit; annular inner circumferential seat portions (seat portions) 20f, 26g, which are arranged radially closer to the fixed end side of the valve body 21, 27 than the ports 20c, 26d and abut against the fixed end side of the valve body 21, 27. The inner peripheral seat portion (seat portion) 20f, 26g has a seat surface 20f1, 26g1 for the valve body 21, 27 to sit on, and the seat surface 20f1, 26g1 has an inclined surface 20f2, 26g2 inclined from the fixed end side of the valve body 21, 27 toward the free end side away from the valve body 21, 27.

[0085] According to the extension-side auxiliary valve EV and the compression-side auxiliary valve CV used as a damping valve constructed in this manner, when the valve bodies 21, 27 are subjected to pressure from the port 20c, 26d side, the valve bodies 21, 27 are flexed to open the ports 20c, 26d and apply resistance to the flow of liquid through the ports 20c, 26d, and when the valve bodies 21, 27 are subjected to pressure pressing toward the valve seat members 20, 26 side, the valve bodies 21, 27 will sit on the annular valve seats 20e, 26f to block the ports 20c, 26d, thereby acting as a damping valve for the flow of liquid attempting to pass through the ports 20c, 26d from one side, and acting as a check valve for the flow of liquid through the ports 20c, 26d from the other side. Furthermore, according to the extension-side auxiliary valve EV and the compression-side auxiliary valve CV used as the damping valve, by providing the seat surfaces 20f1, 26g1 of the inner peripheral seat portions 20f, 26g as the seat portions with inclined surfaces 20f2, 26g2, the fixed end sides of the valve bodies 21, 27 can deform along the inclined surfaces 20f2, 26g2, thereby reducing the bending deformation at the flexure fulcrum and reducing the deformation amount of the inner peripheral portions of the valve bodies 21, 27. In addition, the radial length of the flexible portion of the valve bodies 21, 27 that is not fixed is increased, and when the valve bodies 21, 27 are bent toward the valve seat member, the annular valve seats 20e, 26f of the valve bodies 21, 27 are relatively Figure 2 The reduced slope of the middle and lower end surfaces makes it easier for the valve bodies 21 and 27 to contact the lower end surfaces of the annular valve seats 20e and 26f. Therefore, the expansion-side auxiliary valve EV and the compression-side auxiliary valve CV, which function as damping valves, can function as check valves, tightly sealing the annular valve seats 20e and 26f with the valve bodies 21 and 27 while effectively preventing liquid leakage. As described above, the expansion-side auxiliary valve EV and the compression-side auxiliary valve CV, which function as damping valves in this embodiment, can reduce the stress acting on the valve bodies 21 and 27 when operating as check valves, thereby preventing fatigue in the valve bodies 21 and 27.

[0086] Furthermore, according to the expansion-side auxiliary valve EV and the compression-side auxiliary valve CV used as the damping valve of this embodiment, the stress acting on the valve bodies 21 and 27 can be reduced, thereby increasing the axial distance between the annular valve seats 20e and 26f and the valve bodies 21 and 27, thereby improving the degree of freedom in designing the valve closing timing when operating as a check valve. Figure 2 The seat surface at the middle and lower ends can be designed as an inclined surface parallel to the side surface of the valve seat member of the valve body 21, 27 when the valve body 21, 27 is bent toward the valve seat member. In this case, the valve body 21, 27 is in surface contact with the annular valve seat 20e, 26f, further improving the sealing performance and thus improving the closing ability of the port 20c, 26d.

[0087] Furthermore, in the extension-side auxiliary valve EV and the compression-side auxiliary valve CV used as damping valves in this embodiment, the inclined surfaces 20f2 and 26g2 of the seat surfaces 20f1 and 26f1 and the horizontal surfaces other than the inclined surfaces 20f2 and 26g2 are connected by smooth and continuous surfaces. Therefore, the valve bodies 21 and 27 can be prevented from being deformed due to a sharp change in slope at the flexure fulcrum, and the stress acting on the valve bodies 21 and 27 can be further reduced, thereby further suppressing fatigue of the valve bodies 21 and 27.

[0088] Furthermore, the expansion-side auxiliary valve EV and the compression-side auxiliary valve CV, serving as damping valves in this embodiment, include annular washers 22 and 28 stacked on the side of the valve bodies 21 and 27 opposite the valve seat member, forming a flexure support for the free ends of the valve bodies 21 and 27. Inclined surfaces 20f2 and 26g2 are radially formed on the washers 22 and 28 closer to the free ends of the valve bodies 21 and 27 than the seat surfaces 20f1 and 26f1. Specifically, in this case, the fixed ends of the valve bodies 21 and 27 are on the inner circumference, while the free ends are on the outer circumference. Therefore, the inner diameters of the inclined surfaces 20f2 and 26g2 are larger than the outer diameters of the washers 22 and 28. When the extension side auxiliary valve EV and the compression side auxiliary valve CV constructed in this manner are fixed to the small diameter portion 2a by the piston nut 33, the axial force received from the gaskets 22 and 28 can be applied to the horizontal plane of the inclined surface 20f2 and 26g2 avoiding the inner peripheral seat portion (seat portion) 20f and 26g, thereby avoiding the axial force from acting on the portion of the valve body 21 and 27 that allows the inner periphery to be deflected. Therefore, unnecessary initial deflection of the valve body 21 and 27 can be prevented, thereby avoiding the valve body 21 and 27 from being offset relative to the relatively arranged seat portion 20b and 26b, and preventing fluctuations in the damping force.

[0089] In addition, the inclination angle of the inclined surfaces 20f2, 26g2 on the seat surfaces 20f1, 26g1 is preferably set to the inclination angle (ideal angle) of the portion opposite to the inclined surfaces 20f2, 26g2 of the valve body 21, 27 when it is bent and about to sit on the annular valve seat 20e, 26f, or an angle slightly larger than the ideal angle, but is not limited to this.

[0090] Furthermore, with the expansion-side auxiliary valve EV and the compression-side auxiliary valve CV functioning as damping valves, when the valve bodies 21 and 27 are seated on the annular valve seats 20e and 26f and are subjected to pressure toward the valve seat members 20 and 26, the backup valves 21b and 27b abut against the valve seat members of the leaf valves 21a and 27a, supporting the leaf valves 21a and 27a. This suppresses deflection of the intermediate portions of the leaf valves 21a and 27a, thereby alleviating stress on the leaf valves 21a and 27a and preventing fatigue in the leaf valves 21a and 27a. As described above, the expansion-side auxiliary valve EV and the compression-side auxiliary valve CV functioning as damping valves of this embodiment can both suppress fatigue in the leaf valves 21a and 27a and function as check valves.

[0091] Furthermore, in the above case, the inner circumference of the valve bodies 21 and 27 serves as a fixed end, while the outer circumference serves as a free end. By opposing the outer circumference of the valve bodies 21 and 27 to the inner circumference of the opposing seats 20b and 26b, the expansion-side auxiliary valve EV and the compression-side auxiliary valve CV, which serve as damping valves, are formed. Alternatively, the outer circumference of the valve bodies serves as a fixed end, while the inner circumference serves as a free end. Opposing seats are provided on the inner circumference of the valve bodies, and the damping valve is formed by opposing the inner circumference of the opposing seats. In this case, since the fixed end of the valve body serves as the outer circumference, an inclined surface can be provided on the inner circumference of the seat surface of the seat that abuts the fixed end of the valve body. Since the inner circumference of the valve body serves as the free end, the inclined surface can be inclined from the outer circumference to the inner circumference, away from the valve body, in accordance with the shape of the valve body when it deflects toward the valve seat member. Specifically, when the inner circumference of the valve body is the free end and the outer circumference is the fixed end, the inclined surface only needs to have the inner circumference of the seat surface lower than the outer circumference. In this case, when the valve body's flexure fulcrum is set by a gasket, by making the outer diameter of the inclined surface larger than the inner diameter of the gasket, axial force can be prevented from acting on the portion of the valve body that allows for flexure. This prevents unnecessary initial flexure of the valve body, which could cause the valve body to shift relative to the opposing seat, and thus prevent fluctuations in the damping force.

[0092] In addition, in the above case, it is set that when the valve body 21, 27 is bent toward the valve seat component side and sits on the annular valve seat 20e, 26f, the port 20c, 26d is completely closed, but it can also be designed to provide a groove connecting from the inner periphery to the outer periphery on the annular valve seat 20e, 26f to form a throttling hole, when the valve body 21, 27 is bent toward the valve seat component side and sits on the annular valve seat 20e, 26f, only liquid is allowed to flow through the throttling hole.

[0093] In addition, the valve seat member 26 of the compression-side auxiliary valve CV of the damping valve in this embodiment also has a limiting portion 26h, which is arranged on the fixed end side of the valve body 27 radially closer to the annular valve seat 26f and is axially opposite to the valve body 27. When the free end of the valve body 27 is deflected toward the valve seat member side by more than a specified amount, it abuts against the valve body 27 to limit the deflection of the valve body 27.

[0094] According to the compression-side auxiliary valve CV used as a damping valve constructed in this manner, it is not only supported by the backup valve 27b, but also when the middle part of the valve body 27 is pressed toward the valve seat member side and bends and abuts against the limiting portion 26h, the middle part of the valve body 27 is also supported by the limiting portion 26h to prevent the valve body 27 from further bending. Therefore, even if excessive pressure acts on the valve body 27, the stress acting on the leaf valve 27a can be reduced, and the fatigue of the leaf valve 27a can be further suppressed.

[0095] In addition, in the compression side auxiliary valve CV, the outer diameter of the backup valve 27b is smaller than the inner diameter of the annular valve seat 26f. Only the leaf valve 27a is opposite to the annular valve seat 26f in the axial direction and can be seated thereon, while the backup valve 27b cannot abut against the annular valve seat 26f. However, the outer diameter of the backup valve 27b can also be increased, so that when the valve body 27 is bent toward the valve seat component side, the backup valve 27b is seated on the annular valve seat 26f to close the port 26d. In addition, in the extension-side auxiliary valve EV, the outer diameter of the backup valve 21b is larger than the inner diameter of the annular valve seat 20e, and the backup valve 21b and the leaf valve 21a are both axially opposite to the annular valve seat 20e. When the valve body 21 is bent toward the valve seat component side, the backup valve 21b is seated on the annular valve seat 20e to close the port 20c. However, it can also be designed that the outer diameter of the backup valve 21b is smaller than the inner diameter of the annular valve seat 20e, so that the leaf valve 21a can be seated on the annular valve seat 20e.

[0096] In addition, the buffer D of this embodiment includes: a cylinder (outer tube) 1; a rod 2, which is inserted into the cylinder (outer tube) 1 movably along the axial direction; a buffer body A, which causes the liquid to reciprocate by the movement of the rod 2 relative to the cylinder (outer tube) 1 and has at least an extension side chamber (studio) R1 and a compression side chamber (studio) R2; an extension side auxiliary valve EV and a compression side auxiliary valve CV used as a damping valve, which are arranged between the extension side chamber (studio) R1 and the compression side chamber (studio) R2. In the shock absorber D constructed in this manner, the extension-side auxiliary valve EV generates a damping force when fluid flows from the extension-side chamber R1 to the compression-side chamber R2 and closes the extension-side auxiliary passage EP when fluid flows from the compression-side chamber R2 to the extension-side chamber R1. This allows the damping force characteristics of the shock absorber D to be independently set on the extension side. The compression-side auxiliary valve CV generates a damping force when fluid flows from the compression-side chamber R2 to the extension-side chamber R1 and closes the compression-side auxiliary passage CP when fluid flows from the extension-side chamber R1 to the compression-side chamber R2. This allows the damping force characteristics of the shock absorber D to be independently set on the compression side. Furthermore, the extension-side auxiliary valve EV and the compression-side auxiliary valve CV, acting as damping valves, increase the damping coefficient in the low-speed range of telescopic speed and rapidly increase the damping force with telescopic stroke switching, while maintaining a lower damping coefficient in the low-speed range than in the low-speed range. This results in a damping force characteristic that suppresses vehicle body vibration and improves vehicle ride comfort.

[0097] Furthermore, in the shock absorber D of this embodiment, the extension-side auxiliary valve EV and the compression-side auxiliary valve CV, which function as damping valves, are disposed in the extension-side auxiliary passage EP and the compression-side auxiliary passage CP, which bypass the extension-side passage 3a and the compression-side passage 3b, respectively, of the piston 3. The damping valves are connected in parallel with the extension-side main valve 4 and the compression-side main valve 5 of the piston 3. However, the damping valves may also be utilized as either the extension-side main valve or the compression-side main valve. Furthermore, in the shock absorber D of this embodiment, the extension-side auxiliary valve EV and the compression-side auxiliary valve CV, which function as damping valves, are disposed in the extension-side auxiliary passage EP and the compression-side auxiliary passage CP, which bypass the extension-side passage 3a and the compression-side passage 3b, respectively, of the piston 3. However, it is also possible to provide only the extension-side auxiliary valve EV or only the compression-side auxiliary valve CV in the shock absorber D.

[0098] In addition, if Figure 1 As shown, the two working chambers serve as the expansion-side chamber R1 and the compression-side chamber R2, respectively. However, if the shock absorber D is a multi-tube type shock absorber having a housing serving as an outer tube on the outer periphery of the cylinder and a fluid reservoir between the cylinder and the housing, a damping valve may be provided between the compression-side chamber and the fluid reservoir. Thus, the damping valve port can connect the expansion-side chamber R1 with the compression-side chamber R2, or it can connect the compression-side chamber with the fluid reservoir.

[0099] In addition, in the shock absorber D of this embodiment, the speed range in which the damping force is generated mainly by the extension-side auxiliary valve EV and the compression-side auxiliary valve CV serving as damping valves is set to the low-speed range, but the designer can arbitrarily set the speed values ​​used to divide the speed into slightly low speed, low speed, and speed higher than low speed.

[0100] While the preferred embodiments of the present invention have been described in detail above, modifications, variations, and alterations may be made without departing from the scope of the claims. Explanation of symbols

[0101] 1 cylinder (outer tube) 2 rods 20, 26 valve seat components 20b, 26b are provided with seats opposite to each other Ports 20c and 26d 20e, 26f annular valve seat 20f, 26g inner peripheral seat (seat) 20f1, 26g1 seat surface 20f2, 26g2 inclined surface 21, 27 valve body 22, 28 gaskets A. Buffer body CV compression side auxiliary valve (damping valve) D buffer EV extension side auxiliary valve (damping valve) R1 extension side chamber (working room) R2 Compression side chamber (working room)

Claims

1. A damping valve comprising: An annular valve body, wherein one end of the inner or outer periphery is a fixed end and the other end of the inner or outer periphery is a free end, and the free end is allowed to flex relative to the fixed end; The valve seat member is annular and comprises: an annular relatively arranged seat portion, which is opposite to at least a part of the circumference of the free end side of the valve body; a port, which is arranged on the fixed end side of the valve body in the radial direction than the relatively arranged seat portion; an annular valve seat, which is arranged between the relatively arranged seat portion and the port and is opposite to the valve body in the axial direction and can allow the valve body to be seated; an annular seat portion, which is arranged on the fixed end side of the valve body in the radial direction than the port and abuts against the fixed end side of the valve body, The seat portion has a seat surface for the valve body to sit on; The seat surface has an inclined surface that is inclined in a direction away from the valve body from the fixed end side toward the free end side of the valve body.

2. The damping valve according to claim 1, wherein: It includes a gasket that is annular and stacked on the side of the valve body opposite to the valve seat member and serves as a fulcrum for the deflection of the free end of the valve body. The inclined surface is formed on a free end side of the seat surface that is closer to the valve body than the spacer in the radial direction.

3. A buffer, It comprises a buffer body and the damping valve according to claim 1 or 2, wherein: The buffer body comprises an outer tube, a rod inserted into the outer tube movably in the axial direction, and at least two working chambers in which the liquid is reciprocated by the movement of the rod relative to the outer tube; A damping valve is provided between the working chambers.

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