Valve and shock absorber

Abstract

To provide a valve which can prevent contaminants from being caught by a leaf valve to inhibit variations in characteristics, and to provide a shock absorber which can generate stable damping force.SOLUTION: A valve V of the invention includes: a leaf valve 1 which allows deflection of a free end with one of its inner peripheral side and its outer peripheral side set to a fixed end; and a valve seat member 2 having an annular fixed end-side seat portion 2c, a plurality of ports 2d provided at intervals in a circumferential direction on the free end side of the fixed end-side seat portion 2c, a free end side seat portion 2e with respect to which the free end side of the leaf valve 1 is seated and unseated, and a recessed portion 2f provided over the entire width between the ports 2d and the fixed end-side seat portion 2c. The recessed portion 2f comprises: a first recessed portion 2f1 that is provided on the fixed end-side seat portion side; and a second recessed portion 2f2 that is provided on the port side adjacent to the first recessed portion 2f1 and that is deeper than the first recessed portion 2f1.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a valve and a shock absorber. [Background technology]

[0002] A shock absorber is used, for example, by being interposed between the body and axle of a vehicle in order to improve the ride comfort of the vehicle, and suppresses vibration of the body and wheels by the damping force that it exerts when expanding and contracting.

[0003] Such a shock absorber includes, for example, a cylinder, a piston rod movably inserted into the cylinder, a piston slidably inserted into the cylinder to divide the inside of the cylinder into an extension side chamber and a compression side chamber, a free piston slidably inserted into the cylinder to divide an air chamber below the compression side chamber in the cylinder, a damping passage provided in the piston to communicate between the extension side chamber and the compression side chamber, and a valve provided in the damping passage.

[0004] The valve includes, for example, a piston slidably inserted into the cylinder of the shock absorber, dividing the inside of the cylinder into an expansion-side chamber and a compression-side chamber, and including a port that communicates between the expansion-side chamber and the compression-side chamber, and a leaf valve that is annular and fixed to the piston rod with its inner circumferential side as a fixed end and its outer circumferential side as a free end, and is stacked on the piston while being allowed to flex. The piston also includes an annular seat portion that is provided on the inner circumferential side of the port and on which the inner circumferential side of the leaf valve is stacked, and an outer circumferential seat portion that surrounds the port and abuts against the free end side of the leaf valve. The leaf valve receives pressure from the hydraulic oil passing through the port, and flexes its outer circumferential side, which is the free end, and separates it from the outer circumferential seat portion to open the port, while applying resistance to the flow of hydraulic oil passing through the gap between the outer circumferential seat portion to generate a damping force.

[0005] In a valve configured in this way, when the leaf valve is significantly deflected from the outer periphery, a gap is created between the leaf valve and the inner periphery seat portion that was in close contact with it until then, and the hydraulic oil that was trying to pass through the port is sucked into the gap. Many of the components that make up the shock absorber are manufactured by cutting, and they are washed before assembly to remove cutting chips and burrs, but the chips that cannot be removed by the removal work may remain in the shock absorber as contaminants. In this case, when the leaf valve is significantly deflected, the contaminants floating in the hydraulic oil enter the gap and get caught between the leaf valve and the annular seat portion, so that even if the deflection of the leaf valve is released, it is not possible to close the port because the entire outer periphery seat portion cannot be in close contact with it, or the leaf valve floats up from the outer periphery seat portion, causing the outer periphery of the leaf valve to vibrate and generate abnormal noise.

[0006] Therefore, in conventional valves, the outer diameter of the annular seat portion is made small and a deep recess is provided between the annular seat and the port to prevent contaminants from becoming caught in the leaf valve, thereby solving the above problem (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Utility Model Application Publication No. 63-14038 Summary of the Invention [Problem to be solved by the invention]

[0008] Conventional valves can prevent contaminants from getting caught between the leaf valve and the annular seat of the valve seat member, but require the radial width of the annular seat to be narrow.

[0009] If the radial width of the annular seat is narrowed, a deep recess is formed adjacent to the annular seat, which reduces the strength of the annular seat and causes sagging during molding of the annular seat, making it more likely to cause variation in the flatness of the surface on which the leaf valve seats. This variation has a greater impact on the seating posture of the leaf valve, resulting in a new problem of greater variation in the valve characteristics.

[0010] The new problem could be solved by increasing the radial width of the annular seat, but then a recess could not be provided between the annular seat and the port, and the previous problem of contaminants getting caught in the leaf valve could not be solved. On the other hand, providing a recess between the annular seat and the port and increasing the radial width of the annular seat would result in the valve seat material becoming larger and making it unsuitable for use in a shock absorber, so it is difficult to adopt such a measure.

[0011] Therefore, an object of the present invention is to provide a damping valve that can prevent contaminants from getting caught in the leaf valve and also suppresses variation in characteristics, and a shock absorber that can generate a stable damping force. [Means for solving the problem]

[0012] In order to solve the above-mentioned problems, the valve of the present invention comprises a leaf valve which is annular and has one of the inner and outer circumferential sides as a fixed end and the other of the inner and outer circumferential sides as a free end, an annular fixed end side seat portion which abuts the fixed end of the leaf valve, a plurality of ports arranged circumferentially spaced apart on the free end side of the leaf valve in the fixed end side seat portion, a free end side seat portion which surrounds the ports together with the fixed end side seat portion and on which the free end side of the leaf valve sits and is separated, and a valve seat member having a recess provided between the port and the fixed end side seat portion, wherein the recess has a first recess provided on the fixed end side seat portion side, and a second recess provided on the port side adjacent to the first recess and deeper than the first recess.

[0013] In the valve configured in this manner, a recess is provided between the fixed end seat portion and the port, the recess having a shallow first recess on the fixed end seat portion side and a deep second recess on the port side, so that even if the free end of the leaf valve is bent, liquid is less likely to be drawn into the recess, and even if there is a contaminant in the liquid passing through the port, the contaminant is captured in the deep second recess before entering the first recess, and is prevented from entering between the first recess and the compression side leaf valve. Also, in the valve configured in this manner, even if the recess is provided adjacent to the compression side port side of the fixed end seat portion, a decrease in the strength of the fixed end seat portion is suppressed, and flatness errors are less likely to occur when the fixed end seat portion is molded.

[0014] The depth of the first recess in the valve seat member of the valve may be constant. With a valve configured in this manner, it is possible to prevent contaminants from being caught by the leaf valve while suppressing a decrease in the strength of the valve seat member, and it is easy to ensure the strength of the fixed end side seat portion, so that it is possible to effectively suppress variation in characteristics.

[0015] Furthermore, the valve seat member in the valve may include a land that protrudes from the bottom of the first recess and abuts against the seat member side of the leaf valve to support the leaf valve. With a valve configured in this manner, even if a recess is provided between the fixed end seat portion and the free end seat portion, the land supports the leaf valve, preventing the leaf valve from receiving pressure from the side opposite the seat member and bending towards the seat member side, which would cause a large stress to act on the leaf valve, and suppressing fatigue of the leaf valve.

[0016] The land of the valve may be provided at a position radially opposite the port. With this valve, even if the leaf valve flexes to move contaminants over the second recess into the first recess, the land prevents the contaminants from entering the first recess, further preventing the contaminants from entering the first recess.

[0017] Furthermore, the hardness of the valve seat member in the valve may be lower than that of the leaf valve. With a valve configured in this manner, the hardness of the valve seat member is lower than that of the leaf valve, so that even if contaminants enter the first recess, when the leaf valve bends and returns, the contaminants are struck and embedded in the valve seat member and captured, preventing the leaf valve from floating up from the free end side seat portion and enabling the liquid in the shock absorber to be purified.

[0018] Furthermore, the recess in the valve may be provided across the entire width between the port and the fixed end seat portion of the valve seat member. With a valve configured in this manner, the recess is provided across the entire width between the port and the fixed end seat portion of the valve seat member, which further suppresses the drawing of liquid into the recess due to bending of the free end of the leaf valve, thereby further suppressing the intrusion of contaminants between the first recess and the leaf valve.

[0019] The shock absorber of the present invention includes an outer tube, a rod inserted into the outer tube so as to be axially movable, a shock absorber body having at least two working chambers through which liquid flows as the rod moves relative to the outer tube, and a valve provided between the working chambers. With this type of shock absorber, the valve can exhibit stable characteristics without variation, and therefore a stable damping force can be generated without variation. Effect of the Invention

[0020] The valve of the present invention can prevent contaminants from getting caught in the leaf valve and can also suppress variations in characteristics, and the shock absorber of the present invention can generate a stable damping force. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a vertical cross-sectional view of a shock absorber to which a valve according to an embodiment of the present invention is applied. [Diagram 2] FIG. 2 is an enlarged cross-sectional view of a valve according to an embodiment of the present invention. [Diagram 3] FIG. 3 is a plan view of a valve seat member in a valve according to one embodiment of the present invention. [Figure 4] Fig. 4(a) is a partially enlarged cross-sectional view of a first modified valve seat member in a valve according to an embodiment of the present invention, Fig. 4(b) is a partially enlarged cross-sectional view of a second modified valve seat member in a valve according to an embodiment of the present invention, and Fig. 4(c) is a partially enlarged cross-sectional view of a third modified valve seat member in a valve according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The present invention will be described below based on the embodiment shown in the drawings. As shown in FIG. 1, the valve V in one embodiment is applied to the piston part of a shock absorber D, and includes a compression side leaf valve 1 as a leaf valve having an annular shape with an inner circumferential side as a fixed end and an outer circumferential side as a free end, and a piston 2 as a valve seat member having a compression side port 2d as a port opened and closed by the compression side leaf valve 1. As shown in FIG. 1, the shock absorber D to which the valve V is applied includes a shock absorber body A that is expandable and contractable and has a cylinder 10 as an outer tube and a rod 11 movably inserted into the cylinder 10, and a valve V provided between an expansion side chamber R1 and a compression side chamber R2 as two working chambers provided in the shock absorber body A. In the case of this shock absorber D, it is used by being interposed between a vehicle body and an axle of a vehicle (not shown) to suppress vibration of the vehicle body and wheels.

[0023] Hereinafter, a detailed description will be given of each part of the valve V and the shock absorber D. First, the shock absorber main body A includes a bottomed cylindrical cylinder 10 serving as an outer tube, a rod 11 movably inserted into the cylinder 10, and a piston 2 serving as a valve seat member connected to the rod 11 and movably inserted into the cylinder 10, which divides the inside of the cylinder 10 into an expansion-side chamber R1 and a compression-side chamber R2 serving as working chambers, as shown in FIG.

[0024] A bracket (not shown) is provided at the base end of the rod 11, which is the upper end in Fig. 1, and the rod 11 is connected to one of the vehicle body and the axle via the bracket (not shown). A bracket (not shown) is also provided at the bottom 10a of the cylinder 10, and the cylinder 10 is connected to the other of the vehicle body and the axle via the bracket (not shown).

[0025] In this way, the shock absorber D is interposed between the vehicle body and the axle. When the vehicle runs on an uneven road surface and the wheels vibrate up and down relative to the vehicle body, the rod 11 moves in and out of the cylinder 10, the shock absorber D expands and contracts, and the piston 2 moves up and down (axially) within the cylinder 10.

[0026] The shock absorber body A also includes an annular rod guide 13 that closes the upper end of the cylinder 10 and through which the rod 11 is slidably inserted along its inner periphery. Thus, the inside of the cylinder 10 is an enclosed space. A free piston 14 is slidably inserted into the cylinder 10 on the opposite side of the piston 2 from the rod 11.

[0027] A liquid chamber L is formed above the free piston 14 in the cylinder 10, and an air chamber G is formed below it. The liquid chamber L is further divided by the piston 2 into an extension side chamber R1 on the rod 11 side and a compression side chamber R2 on the piston side, and the extension side chamber R1 and the compression side chamber R2 are each filled with liquid. The liquid filled in the shock absorber body A may be hydraulic oil, water, an aqueous solution, or other liquid. On the other hand, the air chamber G is filled with compressed air or a gas such as nitrogen gas.

[0028] When the rod 11 retreats from the cylinder 10 during the extension operation of the shock absorber D, the free piston 14 moves upward within the cylinder 10 in accordance with the volume of the retreated rod 11, expanding the air chamber G and compensating for the volume of the rod 11 retreating from the cylinder 10. Conversely, when the shock absorber D contracts, the rod 11 advances into the cylinder 10, and the free piston 14 moves downward within the cylinder 10 in accordance with the volume of the advanced rod 11, contracting the air chamber G and compensating for the volume of the rod 11 entering the cylinder 10. Note that instead of the free piston 14, a bladder, a bellows, or the like may be used to separate the liquid chamber L and the air chamber G, and the configuration of the movable partition that serves as this partition can be changed as appropriate.

[0029] As described above, in this embodiment, the shock absorber D is a single-rod, single-cylinder shock absorber, and when the shock absorber D expands or contracts, the free piston (movable partition) 11 expands or contracts the air chamber G to compensate for the volume of the rod 11 moving in and out of the cylinder 10. However, the configuration for this volume compensation can also be changed as appropriate. For example, when the free piston 14 and the air chamber G are eliminated and an outer tube is provided outside the cylinder 10, and a reservoir for storing liquid and gas is formed between the cylinder 10 and the outer tube to make the shock absorber a double-cylinder shock absorber, the volume of the rod 11 moving in and out of the cylinder 10 may be compensated for by the reservoir. The reservoir may be formed in a tank separate from the cylinder 10. The shock absorber D may also be configured as a double-rod shock absorber in which the piston 2 is attached to the center of the rod 11 and the ends of the rod 11 protrude outside the cylinder 10 from both ends of the cylinder 10.

[0030] The rod 11 has a reduced outer diameter at the tip side, and is equipped with a small diameter portion 11a having a small outer diameter at the tip side, a large diameter portion 11b having an outer diameter larger than that of the small diameter portion 11a and provided above the small diameter portion 11a in Figure 1, a step portion 11c provided at the boundary between the small diameter portion 11a and the large diameter portion 11b, and a screw portion 11d provided on the outer periphery of the tip of the small diameter portion 11a.

[0031] The valve V of this embodiment is attached to a rod 11 and applied to a piston portion of a shock absorber D. As shown in Fig. 1, a piston 2 serving as a valve seat member constituting the valve V is annular and fitted to the outer periphery of a small diameter portion 11a of the rod 11, and is fixed to the rod 11 by a piston nut 15 that is screwed into a threaded portion 11d of the rod 11. The piston 2 is also attached to the rod 11, and its outer periphery is in sliding contact with the inner periphery of a cylinder 10, dividing the inside of the cylinder 10 into an expansion-side chamber R1 and a compression-side chamber R2 that serve as working chambers.

[0032] More specifically, the piston 2 includes an annular main body portion 2a, a cylindrical portion 2b provided on the outer periphery of the lower end of the main body portion 2a in FIG. 2, an annular fixed end side seat portion 2c provided on the inner periphery of the upper end of the main body portion 2a in FIG. 2, compression side ports 2d provided at intervals in the circumferential direction on the outer periphery of the fixed end side seat portion 2c of the main body portion 2a and penetrating the main body portion 2a in the axial direction, and a cylindrical portion 2b provided on the outer periphery of the compression side port 2d at the upper end of the main body portion 2a in FIG. 2 and connected to the upper end of the compression side port 2d together with the fixed end side seat portion 2c. 2. The main body portion 2a is provided with a free end side seat portion 2e surrounding the open end of the main body portion 2a, a recess 2f provided at the upper end of the main body portion 2a in FIG. 2 over the entire width between the compression side port 2d and the fixed end side seat portion 2c, an expansion side port 2g provided at the lower end of the main body portion 2a in FIG. 2, opening from the inner peripheral side of the compression side port 2d and opening at the upper end of the main body portion 2a in FIG. 2 on the outer peripheral side of the free end side seat portion 2e, and an annular outer peripheral seat portion 2h provided at the lower end of the main body portion 2a in FIG. 2 between the compression side port 2d and the expansion side port 2g.

[0033] A piston ring 2i is attached to the outer periphery of the main body portion 2a and the cylindrical portion 2b, and the outer periphery of the piston ring 2i is in sliding contact with the inner periphery of the cylinder 10. As shown in Fig. 2 and Fig. 3, the fixed end seat portion 2c is provided on the inner periphery of the upper end of the main body portion 2a in Fig. 2, is annular, and protrudes upward from the recessed portion 2f provided on the outer periphery. The fixed end seat portion 2c has a flat surface on which the compression side leaf valve 1 is laminated at its upper end.

[0034] The free end side seat portion 2e is annular and is provided on the outer circumferential side of the upper end of the main body portion 2a in Figure 2, and functions as a valve seat against which the free end of the compression side leaf valve 1 seats and leaves.It protrudes upward beyond the recess 2f and the outlet end of the compression side port 2d, and is provided at its upper end with a flat surface against which the compression side leaf valve 1 seats and leaves.

[0035] The compression side ports 2d are provided at the expansion side chamber side end, which is the upper end of the main body portion 2a in FIG. 2, and eight of them are provided at equal intervals on the same circumference on the outer periphery of the fixed end side seat portion 2c in FIG. 3, and open from the upper end of the main body portion 2a in FIG. 2, extend along the axial direction, and connect to the lower end of the main body portion 2a. The compression side port 2d is also at the upper end of the main body portion 2a in FIG. 2, and opens on the inner periphery side of the annular free end side seat portion 2e. Furthermore, the compression side port 2d opens on the outer periphery side of the outer periphery seat portion 2h at the lower end of the main body portion 2a in FIG. 2. In this way, the compression side port 2d communicates with the expansion side chamber R1 and the compression side chamber R2.

[0036] An inner seat portion 2j and an outer seat portion 2h arranged on the outer periphery of the inner seat portion 2j are provided at the lower end of the main body portion 2a in Fig. 2. The inner seat portion 2j and the outer seat portion 2h are both annular and protrude in the axial direction from the lower end of the main body portion 2a, and an annular groove is formed between the inner seat portion 2j and the outer seat portion 2h.

[0037] The expansion-side port 2g opens from an annular groove between the inner seat portion 2j and the outer seat portion 2h at the compression-side chamber side end, which is the lower end of the main body portion 2a in Fig. 2, and communicates with the outer periphery of the free-end side seat portion 2e at the upper end of the main body portion 2a in Fig. 2, thereby communicating the expansion-side chamber R1 and the compression-side chamber R2. In this embodiment, the expansion-side port 2g obliquely penetrates between the compression-side ports 2d, 2d of the main body portion 2a so as not to interfere with the compression-side port 2d, and opens at the outer periphery of the free-end side seat portion 2e at the upper end of the main body portion 2a in Fig. 2, and eight of the expansion-side ports 2g are provided at equal intervals in the circumferential direction of the main body portion 2a.

[0038] The recess 2f is provided at the upper end of the main body 2a in Fig. 2 with a first recess 2f1 provided on the fixed end seat portion side which is the inner periphery side, and a second recess 2f2 provided adjacent to the first recess 2f1 on the outer periphery side which is the port side and is deeper than the first recess 2f1. In this embodiment, the recess 2f is provided in an annular shape over the entire circumference between the fixed end seat portion 2c and the compression side port 2d, and the first recess 2f1 and the second recess 2f2 are also formed in annular shapes.

[0039] 2, the radial width of the first recess 2f1 is wider than the radial width of the bottom surface of the second recess 2f2 and is wider than the radial width of the opening side of the second recess 2f2, and the depth of the first recess 2f1 is shallower than the depth of the second recess 2f2. In the valve V of this embodiment, the compression side port 2d opens into the inclined surface on the outer periphery side of the second recess 2f2, but it may open into the outer periphery of the second recess 2f2 without contacting the second recess 2f2.

[0040] The height of the upper end surface of the first recess 2f1 is lower than the height of the upper end surfaces of the fixed end side sheet portion 2c and the free end side sheet portion 2e in Fig. 2, and a recess with a certain depth is formed between the fixed end side sheet portion 2c and the free end side sheet portion 2e. In this embodiment, the depth of the first recess 2f1 from the upper end of the fixed end side sheet portion 2c in Fig. 2 is set to about 0.1 mm to 0.5 mm. The second recess 2f2 is an annular recess that is connected to the outer periphery of the first recess 2f1 and is deeper than the first recess 2f1.

[0041] The valve V of this embodiment is provided with a land 2k formed of a protrusion protruding upward in FIG. 2 from the first recess 2f1. As shown in FIG. 3, the land 2k is provided on the outer periphery of the first recess 2f1, and eight lands 2k are provided radially inward of each compression side port 2d. The upper end surface of the land 2k in FIG. 2 is set to be tangent to a straight line connecting the upper end surface of the fixed end side seat portion 2c and the upper end surface of the free end side seat portion 2e. The land 2k may be one annular or C-shaped, or multiple lands 2k may be provided intermittently in the circumferential direction as shown in FIG. 3. When multiple lands 2k are provided, they may be arc-shaped or may be shaped other than arc-shaped. When the land 2k is annular, the recess 2f may be divided into an inner side and an outer side of the land 2k in the radial direction. The land 2k is provided radially inward of each compression side port 2d, but may be provided in a position other than the radially inward position of the compression side port 2d.

[0042] The compression side leaf valve 1 as a leaf valve is a laminated leaf valve formed by laminating a plurality of annular plates, which are laminated on the upper end of the piston 2 as a valve seat member in FIG. 2, and is fixed to the outer periphery of the small diameter portion 11a of the rod 11 together with the piston 2. The compression side leaf valve 1 has an inner periphery side of the lowermost annular plate 1a as a fixed end 1b fixed to the rod 11, which abuts against a fixed end side seat portion 2c, and an outer periphery side as a free end 1c which is allowed to bend in a direction away from the piston 2, and the free end side is seated on and removed from a free end side seat portion 2e.

[0043] When the free end 1c of the compression-side leaf valve 1 is seated on the free-end seat portion 2e, the compression-side leaf valve 1 is in close contact with the fixed-end seat portion 2c and the free-end seat portion 2e to block the outlet end of the compression-side port 2d that opens between the fixed-end seat portion 2c and the free-end seat portion 2e, and when the free end 1c is bent by the pressure from the compression-side port 2d side and separated from the free-end seat portion 2e, the compression-side port 2d is opened and resistance is given to the flow of liquid passing through the gap generated between the free-end seat portion 2e and the free-end seat portion 2e. Even if the compression-side leaf valve 1 is pressed toward the piston 2 by the pressure of the expansion-side chamber R1 with the free end 1c seated on the free-end seat portion 2e, the land 2k supports the intermediate portion between the fixed-end seat portion 2c and the free-end seat portion 2e of the compression-side leaf valve 1, and the intermediate portion is bent in a convex shape toward the recessed portion 2f, so that a large stress is not applied to the compression-side leaf valve 1. 2, which is the contact surface of the land 2k that contacts the compression-side leaf valve 1, is set to be tangent to a straight line connecting the upper end surface of the fixed-end seat portion 2c and the upper end surface of the free-end seat portion 2e, so that when the compression-side leaf valve 1 is supported by the land 2k, the portion between the portion of the compression-side leaf valve 1 that contacts the outer peripheral edge of the fixed-end seat portion 2c and the inner peripheral edge of the free-end seat portion 2e is supported without being significantly bent along the way. Therefore, the middle portion of the compression-side leaf valve 1 is supported by the land 2k without being bent toward the piston 2 under pressure from the expansion-side chamber R1, so that fatigue of the compression-side leaf valve 1 is effectively suppressed. Furthermore, since the land 2k is required to be able to support the middle portion of the compression side leaf valve 1 while not hindering the compression side leaf valve 1 from seating on the free end side seat portion 2e, the height of the abutment surface of the land 2k that abuts against the compression side leaf valve 1 may be set to less than the height tangent to a straight line connecting the upper end surface of the fixed end side seat portion 2c and the upper end surface of the free end side seat portion 2e, as long as it protrudes upward from the first recess 2f1 in Figure 2.

[0044] 2, a valve stopper 4 having a circular shape and attached to the outer periphery of the small diameter portion 11a of the rod 11 is laminated. When the free end 1c of the compression side leaf valve 1 bends upward away from the piston 2 in the figure and abuts against the upper surface of the outer periphery of the compression side leaf valve 1, the valve stopper 4 restricts further bending of the compression side leaf valve 1 in the direction away from the piston 2, thereby protecting the compression side leaf valve 1 from excessive stress.

[0045] Incidentally, the piston 2 serving as the valve seat member is manufactured by sintering, while the compression side leaf valve 1 serving as the leaf valve is formed of an annular plate obtained by punching a steel plate, and the hardness of the piston 2 is lower than that of the compression side leaf valve 1. The above-mentioned manufacture and materials of the piston 2 and the compression side leaf valve 1 are merely an example, and in order to make the hardness of the piston 2 lower than that of the compression side leaf valve 1, it is sufficient to select a material such that the hardness of the piston 2 is lower than that of the compression side leaf valve 1, and the design of the manufacturing method can be changed as desired.

[0046] The extension-side leaf valve 3 is laminated below the piston 2 in FIG. 1. The extension-side leaf valve 3 is a laminated leaf valve formed by laminating a plurality of annular plates, and is laminated at the lower end of the piston 2 as a valve seat member in FIG. 2, and is fixed to the outer periphery of the small diameter part 11a of the rod 11 together with the piston 2. The inner periphery side of the lowermost annular plate of the extension-side leaf valve 3 is in contact with the inner periphery seat part 2j, and the inner periphery side fixed to the rod 11 is the fixed end, and the outer periphery side is the free end. Therefore, the extension-side leaf valve 3 is allowed to bend in a direction away from the piston 2 on the outer periphery side, which is the free end side, and the outer periphery side is seated on and off the outer periphery seat part 2h.

[0047] When the expansion-side leaf valve 3 has its free end seated on the outer peripheral seat portion 2h, it is in close contact with the inner peripheral seat portion 2j and the outer peripheral seat portion 2h to block the outlet end of the expansion-side port 2g opening between the inner peripheral seat portion 2j and the outer peripheral seat portion 2h. When the free end is bent by pressure from the expansion-side port 2g side and separated from the outer peripheral seat portion 2h, the expansion-side port 2g is opened and resistance is applied to the flow of liquid passing through the gap generated between the expansion-side leaf valve 3 and the outer peripheral seat portion 2h.

[0048] The valve stopper 4, the compression side leaf valve 1, the piston 2 and the extension side leaf valve 3 configured in this manner are successively assembled to the outer periphery of the small diameter portion 11a of the rod 11, and then are fixed to the rod 11 by being clamped between the piston nut 15, which is screwed to the threaded portion 11d of the small diameter portion 11a, and the step portion 11c of the rod 11.

[0049] The valve V and the shock absorber D are configured as described above, and their operation will be described below. First, when the shock absorber D performs an extension operation and the piston 2 moves upward in FIG. 1 relative to the cylinder 10, the liquid in the extension-side chamber R1, which is compressed by the upward movement of the piston 2 in FIG. 1, bends the extension-side leaf valve 3 and moves to the compression-side chamber R2 through the extension-side port 2g. Therefore, when the shock absorber D performs an extension operation, the extension-side leaf valve 3 provides resistance to the flow of liquid from the extension-side chamber R1 to the compression-side chamber R2, increasing the pressure in the extension-side chamber R1, so that the shock absorber D generates an extension-side damping force that hinders the extension operation. In addition, with the extension operation of the shock absorber D, the free piston 14 rises in FIG. 1 according to the volume of the rod 11 that retreats from the cylinder 10, expanding the air chamber G, and the volume of the rod 11 that retreats from the cylinder 10 is compensated.

[0050] On the other hand, when the shock absorber D contracts and the piston 2 moves downward in FIG. 1 relative to the cylinder 10, the downward movement of the piston 2 in FIG. 1 causes the liquid in the compression-side chamber R2 to bend the compression-side leaf valve 1 and move to the expansion-side chamber R1 through the compression-side port 2d.

[0051] More specifically, when the shock absorber D contracts, the pressure in the compression side chamber R2 acts on the lower surface of the compression side leaf valve 1 in FIG. 2 through the compression side port 2d, and the free end 1c of the compression side leaf valve 1 is bent and separated from the free end side seat portion 2e by the action of the pressure, and the liquid in the compression side chamber R2 moves to the extension side chamber R1 through the gap between the compression side leaf valve 1 and the free end side seat portion 2e. Therefore, when the shock absorber D contracts, the compression side leaf valve 1 provides resistance to the flow of liquid from the compression side chamber R2 to the extension side chamber R1, increasing the pressure of the compression side chamber R2, so that the shock absorber D generates a compression side damping force that hinders the contraction operation. In addition, with the contraction operation of the shock absorber D, the free piston 14 descends in FIG. 1 according to the volume of the rod 11 that enters the cylinder 10, reducing the air chamber G, and the volume of the rod 11 that enters the cylinder 10 is compensated.

[0052] Here, during contraction of the shock absorber D, the compression-side leaf valve 1 has its inner circumferential side abutted against the fixed end seat portion 2c as the fixed end 1b and its outer circumferential side seated on the free end seat portion 2e as the free end 1c until it opens, and a recess 2f is provided on the inner circumferential side of the compression-side port 2d, and the recess 2f faces, with a gap therebetween, the lower surface of the compression-side leaf valve 1. Therefore, even if the gap between the compression-side leaf valve 1 and the recess 2f is enlarged when the free end 1c of the compression-side leaf valve 1 is bent to open, the first recess 2f1 and the second recess 2f2 in the recess 2f are already filled with liquid, and liquid is unlikely to be drawn into the recess 2f even if the compression-side leaf valve 1 is bent.

[0053] In addition, the recess 2f has a second recess 2f2 that is deeper than the first recess 2f1, which has a shallow depth, and is closer to the compression side port 2d than the first recess 2f1, so that contaminants such as cutting chips and iron powder in the liquid are captured by the deeper second recess 2f2 before they enter the first recess 2f1, thereby preventing them from entering between the first recess 2f1 and the compression side leaf valve 1.

[0054] Furthermore, in the valve V of this embodiment, a land 2k is provided on the inside, which is the fixed end side of the compression side leaf valve 1 in the radial direction of the compression side port 2d, so that even if the contaminant attempts to overcome the second recess 2f2 and move into the first recess 2f1 due to the bending action of the compression side leaf valve 1, the land 2k gets in the way and makes it difficult for the contaminant to reach the first recess 2f1.

[0055] In addition, even if contaminants larger than the height difference between the compression-side leaf valve 1 and the bottom surface of the first recess 2f1 of the piston 2 when the compression-side leaf valve 1 is seated on the free-end side seat portion 2e enter the first recess 2f1 when the compression-side leaf valve 1 is deflected, in the valve V of this embodiment, the hardness of the piston 2 is lower than the hardness of the compression-side leaf valve 1, so that when the compression-side leaf valve 1 is deflected many times and repeatedly seats and leaves the free-end side seat portion 2e, the contaminants are repeatedly struck by the compression-side leaf valve 1 and embedded in the bottom of the first recess 2f1, and eventually do not interfere with the compression-side leaf valve 1. Therefore, in the valve V of this embodiment, even if contaminants enter the first recess 2f1, the contaminants are embedded and captured in the main body portion 2a of the piston 2, and the compression-side leaf valve 1 is prevented from floating up from the free-end side seat portion 2e and the liquid in the shock absorber D can be purified.

[0056] In addition, since the recess 2f is made up of the first recess 2f1 with a shallow depth on the fixed end side and the second recess 2f2 with a deep depth, compared to the conventional valve V in which a recess with a sudden increase in depth is formed in the fixed end seat portion, even if the recess 2f is provided adjacent to the compression side port side of the fixed end seat portion 2c, the strength of the fixed end seat portion 2c is suppressed from decreasing, and flatness errors are less likely to occur during molding of the fixed end seat portion 2c. Therefore, the seating of the fixed end seat portion 2c of the piston 2 of the compression side leaf valve 1 is stable, and the resistance that the valve V provides to the flow of liquid is stable.

[0057] As described above, the valve V of this embodiment comprises: a compression side leaf valve (leaf valve) 1 which is annular and has an inner circumferential side as a fixed end and an outer circumferential side as a free end; an annular fixed end side seat portion 2c which abuts against the fixed end of the compression side leaf valve (leaf valve) 1; a plurality of compression side ports (ports) 2d which are provided at intervals in the circumferential direction on the free end side of the leaf valve 1 in the fixed end side seat portion 2c; a free end side seat portion 2e which surrounds the compression side port (port) 2d together with the fixed end side seat portion 2c and on which the free end side of the compression side leaf valve (leaf valve) 1 is seated and separated; and a piston (valve seat member) 2 which has a recess 2f provided between the compression side port (port) 2d and the fixed end side seat portion 2c, wherein the recess 2f comprises a first recess 2f1 provided on the fixed end side seat portion side; and a second recess 2f2 which is provided on the port side adjacent to the first recess 2f1 and is deeper than the first recess 2f1.

[0058] In the valve V configured in this manner, a recess 2f is provided between the fixed end seat portion 2c and the compression side port (port) 2d, the recess 2f including a first recess 2f1 having a shallow depth on the fixed end seat portion side and a second recess 2f2 having a deep depth on the port side, so that even if the free end 1c of the compression side leaf valve (leaf valve) 1 is bent, liquid is not easily drawn into the recess 2f, and even if there is a contaminant in the liquid passing through the compression side port (port) 2d, the contaminant is captured by the deep second recess 2f2 before entering the first recess 2f1, and is prevented from entering between the first recess 2f1 and the compression side leaf valve (leaf valve) 1. In addition, in the valve V configured in this manner, even if the recess 2f is provided adjacent to the compression side port side of the fixed end seat portion 2c, a decrease in the strength of the fixed end seat portion 2c is suppressed, and an error in flatness is less likely to occur when the fixed end seat portion 2c is molded.

[0059] As described above, the valve V of this embodiment can prevent the trapping of contaminants in the compression side leaf valve (leaf valve) 1 and suppress variations in damping force, thereby achieving stable characteristics without variations. Furthermore, the valve V of this embodiment can prevent the trapping of contaminants in the compression side leaf valve (leaf valve) 1, thereby preventing abnormal noise caused by the trapping of contaminants in the compression side leaf valve (leaf valve) 1.

[0060] In addition, in the valve V of this embodiment, the depth of the first recess 2f1 in the recess 2f is constant. By making the depth of the first recess 2f1 constant in this manner, it is possible to prevent the compression side leaf valve (leaf valve) 1 from biting contaminants while suppressing a decrease in the strength of the piston (valve seat member) 2, and it is easy to ensure the strength of the fixed end side seat portion 2c, so that the variation in the characteristics of the valve V can be suppressed and the variation in the damping force can be effectively suppressed. Note that, as shown in FIG. 4, the depth of the first recess 2f1 may be deeper toward the compression side port (port) 2d as long as it is not deeper than the depth of the second recess 2f2. For example, the bottom surface of the first recess 2f1 may be a tapered surface as shown in FIG. 4(a), the bottom surface of the first recess 2f1 may be a curved surface as shown in FIG. 4(b), or the bottom surface of the first recess 2f1 may gradually become deeper in a stepped manner as shown in FIG. 4(c). In addition, when the bottom surface of the first recess 2f1 is a tapered surface, the inclination angle of the bottom surface of the first recess 2f1 is smaller than the inclination angle of the inner inclined surface of the bottom surface of the second recess 2f2, and the gradient rate of the bottom surface of the first recess 2f1 is lower than the gradient rate of the inner inclined surface of the bottom surface of the second recess 2f2.

[0061] In this way, when the depth of the first recess 2f1 is set to become deeper toward the compression side port (port) 2d, the gap between the compression side leaf valve (leaf valve) 1 and the first recess 2f1 becomes wider toward the compression side port (port) 2d, so that the force sucking liquid into the first recess 2f1 when the compression side leaf valve (leaf valve) 1 deflects is weakened, thereby improving the effect of preventing contaminants from entering the first recess 2f1.

[0062] Furthermore, the piston (valve seat member) 2 in the valve V of this embodiment is provided with a land 2k that protrudes from the bottom of the first recess 2f1 and abuts against the valve seat member side of the compression-side leaf valve (leaf valve) 1 to support the compression-side leaf valve (leaf valve) 1. With the valve V configured in this manner, even if a recess 2f is provided between the fixed-end side seat portion 2c and the free-end side seat portion 2e, the land 2k supports the compression-side leaf valve (leaf valve) 1, preventing the compression-side leaf valve (leaf valve) 1 from receiving pressure from the anti-piston (valve seat member) side and bending toward the piston (valve seat member) side to apply a large stress to the compression-side leaf valve (leaf valve) 1, thereby suppressing fatigue of the compression-side leaf valve (leaf valve) 1.

[0063] Furthermore, the land 2k in the valve V of this embodiment is provided at a position radially opposite to the compression-side port (port) 2d. With the valve V configured in this manner, even if the contaminants attempt to move beyond the second recess 2f2 and into the first recess 2f1 due to the bending action of the compression-side leaf valve (leaf valve) 1, the land 2k hinders them, so that the intrusion of the contaminants into the first recess 2f1 can be further suppressed.

[0064] Furthermore, the hardness of the piston (valve seat member) 2 in the valve V of this embodiment is lower than the hardness of the contraction-side leaf valve (leaf valve) 1. According to the valve V configured in this manner, the hardness of the piston (valve seat member) 2 is lower than the hardness of the contraction-side leaf valve (leaf valve) 1. Therefore, even if contaminants enter the first recess 2f1, when the contraction-side leaf valve (leaf valve) 1 bends and returns, the contaminants are struck and embedded in and captured by the piston (valve seat member) 2, so that the contraction-side leaf valve (leaf valve) 1 is prevented from floating up from the free end seat portion 2e and the liquid in the shock absorber D can be purified.

[0065] Furthermore, the recess 2f in the valve V of this embodiment is provided over the entire width between the compression side port (port) 2d and the fixed end side seat portion 2c in the piston (valve seat member) 2. In the valve V configured in this manner, since the recess 2f is provided over the entire width between the compression side port (port) 2d and the fixed end side seat portion 2c in the piston (valve seat member) 2, drawing of liquid into the recess 2f due to bending of the free end 1c of the compression side leaf valve (leaf valve) 1 is further suppressed, and therefore intrusion of contaminants between the first recess 2f1 and the compression side leaf valve (leaf valve) 1 can be further suppressed.

[0066] The shock absorber D of this embodiment includes a cylinder (outer tube) 10, a rod 11 inserted axially movably into the cylinder (outer tube) 10, a shock absorber body A having at least an extension side chamber (operating chamber) R1 and a compression side chamber (operating chamber) R2 through which liquid flows by the movement of the rod 11 relative to the cylinder (outer tube) 10, and a valve V provided between the extension side chamber (operating chamber) R1 and the compression side chamber (operating chamber) R2. According to the shock absorber D configured in this manner, the valve V provides a stable resistance to the flow of liquid without variation, so that a stable damping force can be generated without variation. Therefore, if the shock absorber D is used for a vehicle suspension, the ride comfort of the vehicle can be improved and abnormal noise caused by the bite of contaminants in the compression side leaf valve (leaf valve) 1 can be prevented.

[0067] 1, the two working chambers are the expansion-side chamber R1 and the compression-side chamber R2, and the leaf valve is the compression-side leaf valve 1, but the leaf valve may be the expansion-side leaf valve 3 and the port may be the expansion-side port 2g, and a recess may be provided on the compression-side chamber side of the piston 2 to apply the valve of the present invention to a valve that generates an expansion-side damping force. Also, when the shock absorber D is a double-tube shock absorber that has an outer shell as an outer tube on the outer periphery of the cylinder and a reservoir between the cylinder and the outer shell, a valve seat member and a leaf valve may be provided between the compression-side chamber and the reservoir, and a valve V may be provided between the compression-side chamber and the reservoir.

[0068] Furthermore, as described above, both the fixed end side sheet portion 2c and the free end side sheet portion 2e are annular sheet portions, and the recess 2f is also annular, but the free end side sheet portion may be a petal-shaped sheet portion that is connected to the outer periphery of the annular fixed end side sheet portion 2c and independently surrounds each port, and in that case, the recess provided between the fixed end side sheet portion and the port may also not be annular, but may be provided with a recess having a first recess and a second recess that are independently provided on the fixed end side sheet portion side of each port.

[0069] In the above, the inner periphery of the contraction-side leaf valve (leaf valve) 1 is fixed to the small diameter portion 11a of the rod 11, and the contraction-side leaf valve (leaf valve) 1 is set to open outward, with the inner periphery as the fixed end 1b and the outer periphery as the free end 1c, allowing bending on the outer periphery side, but when the leaf valve is set to open inward, with the outer periphery as the fixed end and the inner periphery as the free end, allowing bending on the inner periphery side, the valve seat member may be annular, a fixed end seat portion may be provided on the outer periphery side of the valve seat member, and a free end seat portion may be provided on the inner periphery side, and a first recess, a second recess, and a port may be provided in this order from the outer periphery side of the valve seat member between the fixed end seat portion and the free end seat portion. Even in a valve with a minimum number of leaf valves set to open inward, the valve seat member has the first recess and the second recess provided closer to the fixed end seat portion than the port, so that it is possible to prevent contaminants from being caught by the leaf valve and to suppress variation in force. Furthermore, in the above description, valve V is used as a damping valve that exerts a damping force by providing resistance to the flow of liquid passing through a port when the valve is open, but it may also be used as a check valve that provides almost no resistance to the flow of liquid passing through a port when the valve is open. In this way, even if valve V is used as a check valve, it is possible to prevent contaminants from being caught by the leaf valve and to suppress variation in the characteristics of the check valve.

[0070] Although the preferred embodiment of the present invention has been described in detail above, modifications, variations and changes can be made without departing from the scope of the appended claims. [Explanation of symbols]

[0071] 1 leaf valve, 1b fixed end, 1c free end, 2 piston (valve seat member), 2c fixed end side seat portion, 2d compression side port (port), 2e free end side seat portion, 2f recess, 2f1 first recess, 2f2 second recess, 10 cylinder (outer tube), 11 rod, A shock absorber body, D shock absorber, V valve, R1 extension side chamber (operating chamber), R2 compression side chamber (operating chamber)

Claims

1. a leaf valve having an annular shape, with one of an inner circumferential side and an outer circumferential side being a fixed end and the other of the inner circumferential side and the outer circumferential side being a free end; a valve seat member having an annular fixed end seat portion that abuts against the fixed end of the leaf valve, a plurality of ports provided at intervals in the circumferential direction on the free end side of the leaf valve in the fixed end seat portion, a free end seat portion that surrounds the ports together with the fixed end seat portion and on which the free end side of the leaf valve seats and disengages, and a recess provided between the ports and the fixed end seat portion, The recess includes a first recess provided on the fixed end side seat portion side, and a second recess provided on the port side adjacent to the first recess and deeper than the first recess. A valve characterized by:

2. The depth of the first recess is constant.

2. The valve according to claim 1 .

3. The valve seat member has a land that protrudes from the bottom of the first recess and abuts against the leaf valve on the valve seat member side to support the leaf valve.

2. The valve according to claim 1 .

4. The land is provided at a position radially opposite the port.

4. The valve according to claim 3.

5. The hardness of the valve seat member is lower than the hardness of the leaf valve.

2. The valve according to claim 1 .

6. The recess is provided over the entire width between the port and the fixed end side seat portion of the valve seat member.

2. The valve according to claim 1 .

7. a shock absorber body including an outer tube, a rod inserted into the outer tube so as to be movable in an axial direction, and at least two working chambers through which liquid flows in response to movement of the rod relative to the outer tube; and a valve according to any one of claims 1 to 6 provided between the working chambers. A shock absorber characterized by:

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