Valve and damper

Abstract

To provide a valve which can suppress vibration in a lateral direction of a valve body and generate stable damping force.SOLUTION: A valve V of the invention includes: a valve seat member 10 having a port 10c and an annular valve seat 10e provided around an outlet end of the port 10c; a valve body 11 which may move close to or away from the annular valve seat 10e and is seated on or separate from the annular valve seat 10e; and a spring 12 which biases the valve body 11 to the annular valve seat 10e. The valve body 11 has: a slide contact part 11a which is slidably inserted into an inner periphery of the port 10c; and a discoid seat part 11b which is connected to a rear end of the slide contact part 11a and seated on or separates from the annular valve seat 10e. A natural frequency of the valve body 11 when the slide contact part 11a is considered as a spring is higher than a natural frequency of a spring mass system comprising the valve body 11 and the spring 12.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Valves are used, for example, in dampers and cylinder devices, and provide resistance to the flow of hydraulic oil that accompanies the expansion and contraction of the damper, allowing the damper to exert a damping force, or open when the pressure in the working chamber of the damper reaches the valve opening pressure, preventing the pressure in the working chamber from becoming excessive.

[0003] Such a valve includes, for example, a piston inserted into a cylinder of a double-tube damper to divide the interior of the cylinder into a rod-side chamber and a piston-side chamber, and a valve case provided at the end of the cylinder as a housing, the housing, an annular valve seat provided on the inner periphery of a valve hole provided in the housing, a valve body inserted into the valve hole so as to be freely movable in the axial direction and seated on and off the annular valve seat, and a coil spring that urges the valve body toward the annular valve seat (see, for example, Patent Document 1).

[0004] The valve element of the valve has a tip portion that is slidably inserted into a small-diameter portion that forms a port in the valve hole, and a seat portion that is connected to the rear end of the tip portion and seats on and off the annular valve seat.The tip portion is bifurcated and has a slit that opens from the tip to allow a large flow rate to pass when the valve is open.

[0005] When the pressure on the port side of the valve configured in this manner reaches the valve opening pressure, the valve element is pressed by the pressure and moves away from the annular valve seat, opening the valve and allowing hydraulic oil to flow through the valve hole via the slit. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-295565 Summary of the Invention [Problem to be solved by the invention]

[0007] In this conventional valve, when the seating portion separates from the annular valve seat, a portion of the forked tip portion having a slit is inserted into the port, and the valve body is supported by the tip portion.

[0008] Furthermore, if a large flow rate is required to pass through when the valve is open, it is desirable to increase the slit width. However, increasing the slit width reduces the rigidity of the tip, and if part of the tip is supported by the housing when the valve is open, lateral vibrations are excited in the radial direction of the valve body, generating noise and causing the damping force to vibrate and become unstable.

[0009] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a valve that can suppress lateral vibration of the valve body and generate a stable damping force, and a damper suitable for the valve. [Means for solving the problem]

[0010] The valve of the present invention comprises a valve seat member having a port and an annular valve seat provided around the outlet end of the port, a valve disc that can move toward and away from the annular valve seat and seats on and off the annular valve seat, and a spring that urges the valve disc toward the annular valve seat, wherein the valve disc has a sliding contact portion that is slidably inserted into the inner periphery of the port and a disk-shaped seat portion that is connected to the rear end of the sliding contact portion and seats on and off the annular valve seat, and the natural frequency of the valve disc when the sliding contact portion is viewed as a spring is higher than the natural frequency of the spring-mass system consisting of the valve disc and spring.

[0011] With a valve configured in this manner, the natural frequency of the valve body when viewed as a spring is greater than the natural frequency of the spring-mass system consisting of the valve body and the spring. Therefore, even if the valve body vibrates axially when the valve is opened, radial vibration of the valve body is not excited, and vibration of the valve body itself can be suppressed.

[0012] In addition, the sliding contact portion in the valve may have a pair of flow path formers that rise from the seat, face each other, and slide against the inner periphery of the port to form a flow path therebetween, and a reinforcing portion provided between the flow path formers, and the ratio of the width of the flow path to the radial width of the sliding contact portion may be 1 / 3 or more.

[0013] With a valve configured in this manner, the ratio of the width of the flow path to the radial width of the sliding contact part is set to 1 / 3 or more, ensuring a large flow path area and reducing pressure override on the flow rate passing through when the valve is open, while at the same time, by providing reinforcing parts between the flow path forming bodies, the flow path forming bodies are integrated rather than being independent of each other, thereby increasing the bending rigidity of the sliding contact part, suppressing radial vibration of the valve body, preventing the generation of noise, generating a stable damping force, and achieving good relief characteristics with little pressure override.

[0014] Furthermore, the sliding contact portion of the valve may be cylindrical and have three or more grooves on its outer periphery that extend from the front end to the rear end to form a flow path. With a valve configured in this way, by providing three or more grooves distributed circumferentially on the outer periphery of the sliding contact portion, it is possible to make the center portion of the sliding contact portion solid and improve bending rigidity while ensuring a sufficient flow path area, thereby preventing noise generation, generating a stable damping force, and achieving good relief characteristics with little pressure override.

[0015] The damper of the present invention also includes a cylinder, a piston rod movably inserted into the cylinder in the axial direction, an annular piston movably inserted into the cylinder and connected to the outer periphery of the piston rod, and a valve, wherein the valve seat member closes the end of the cylinder and faces the tip of the piston rod in the axial direction, and the piston rod has an escape hole directly opposite the port in the axial direction to allow insertion of the sliding contact portion of the valve body.

[0016] With a damper configured in this manner, the piston rod is provided with an escape hole that opens from the tip and allows the sliding contact portion to be inserted. Therefore, even if the thickness of the valve seat member in the valve from the annular valve seat to the tip of the protruding portion is thinned and the entire length of the sliding contact portion is ensured to be such that it does not slip out of the port, it is possible to avoid contact between the piston rod and the sliding contact portion of the valve body, and the stroke length of the damper can be ensured by expanding the limit of movement of the piston rod toward the contraction side when the damper contracts. [Effects of the Invention]

[0017] The valve and damper of the present invention can suppress lateral vibration of the valve body and generate a stable damping force. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a vertical cross-sectional view of a damper to which a valve according to an embodiment is applied; [Figure 2] FIG. 2 is an enlarged cross-sectional view of a valve according to one embodiment. [Figure 3] FIG. 2 is a front view of the valve body of the valve according to the embodiment. [Figure 4] FIG. 10 is a perspective view of a valve body of a valve according to a first modified example of the embodiment. [Figure 5] 10 is a diagram showing the damping force characteristics during contraction of a damper to which a valve is applied according to an embodiment of the present invention. FIG. [Figure 6] FIG. 10 is a cross-sectional view of a valve according to a second modified example of the embodiment. [Figure 7] FIG. 10 is a cross-sectional view of a valve according to a third modified example of the embodiment. [Figure 8] FIG. 10 is a perspective view of a valve body of a valve according to a fourth modified example of the embodiment. [Figure 9] FIG. 13 is a perspective view of a valve body of a valve according to a fifth modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention will be described below based on the illustrated embodiments. As shown in Figures 1 and 2, a valve V in one embodiment includes a valve seat member 10 having an annular valve seat 10e, a valve element 11 that seats on and releases from the annular valve seat 10e, and a spring 12 that biases the valve element 11 toward the annular valve seat 10e, and is used as a base valve that generates a compression-side damping force in a damper D.

[0020] Each component of the valve V will be described in detail below. As shown in Fig. 1, the damper D to which the valve V is applied includes: a cylinder 1, a piston rod 2 movably inserted into the cylinder 1, a piston 3 movably inserted into the cylinder 1 and connected to the piston rod 2, and dividing the interior of the cylinder 1 into an extension-side chamber R1 and a compression-side chamber R2 filled with liquid, an outer tube 4 covering the outer periphery of the cylinder 1 and forming a tank T for storing liquid between the cylinder 1 and the outer tube 4, an annular rod guide 5 closing the left ends of the cylinder 1 and the outer tube 4 in Fig. 1 and guiding the axial movement of the piston rod 2 inserted into the inner periphery, a valve V having a valve seat member 10 closing the right end of the cylinder 1 in Fig. 1 and providing flow resistance for liquid from the compression-side chamber R2 to the tank T, a bottom cap 6 closing the right end of the outer tube 4 in Fig. 1, an extension-side damping valve 7 provided in the piston 3, a check valve 8 provided in the piston 3, and a suction check valve 9 provided in the valve seat member 10.

[0021] The liquid in the expansion-side chamber R1, the compression-side chamber R2, and the tank T may be, for example, hydraulic oil, but water or an aqueous solution may also be used instead of hydraulic oil. The tank T is filled with gas in addition to the liquid.

[0022] The cylinder 1 is cylindrical, and has an annular rod guide 5 attached to its left end in Fig. 1, closing the open end thereof, and a valve seat member 10 attached to its right end in Fig. 1, closing the open end thereof. The piston rod 2 is inserted into the cylinder 1 via the inner periphery of the rod guide 5 so as to be movable in the axial direction, and its left end in Fig. 1 protrudes outward from the cylinder 1.

[0023] The cylinder 1 is housed in an outer tube 4. The left end of the outer tube 4 in FIG. 1 is closed by a rod guide 5, and the right end in FIG. 1 is closed by a bottom cap 6. In this way, the left and right open ends of the outer tube 4 are closed by the rod guide 5 and the bottom cap 6, respectively, and together with the cylinder 1, an annular gap forms a tank T.

[0024] When the rod guide 5 and the bottom cap 6 are fixed to the left and right ends of the outer tube 4, the cylinder 1 and the valve seat member 10 that closes the right end of the cylinder 1 are sandwiched between the rod guide 5 and the bottom cap 6, and the cylinder 1 and the valve seat member 10 are fixed to the outer tube 4.

[0025] 1, the piston 3 inserted into the cylinder 1 is connected to the outer periphery of the right end of the piston rod 2 inserted into the cylinder 1, and a bracket (not shown) is provided on the left end (in FIG. 1) of the piston rod 2 protruding out of the cylinder 1 for attaching the damper D to an external device such as a railway vehicle (not shown). Also, although not shown, a bracket for attaching the damper D to the external device is provided on the bottom cap 6, and the brackets provided on the bottom cap 6 and the piston rod 2 can be used to install the damper D on the external device.

[0026] The piston rod 2 also includes a small-diameter portion 2a provided at the right end in FIG. 1 and having an outer diameter smaller than that on the left side, a step portion 2b formed at the boundary between the small-diameter portion 2a and the left side of the small-diameter portion 2a, a thread portion 2c formed on the outer periphery of the small-diameter portion 2a on the tip side, which is the right end in FIG. 1, and an escape hole 2d opening from the tip of the small-diameter portion 2a.

[0027] Next, the piston 3 is annular and is fitted onto the outer periphery of the small diameter portion 2a of the piston rod 2, and is fixed to the piston rod 2 by a nut 15 that is screwed onto the threaded portion 2c of the small diameter portion 2a. The piston 3 is inserted into the cylinder 1 with its outer periphery in sliding contact with the inner periphery of the cylinder 1, and can move together with the piston rod 2 relative to the cylinder 1 in the left-right direction in FIG. 1, which is the axial direction. The piston 3 divides the interior of the cylinder 1 into an extension-side chamber R1 and a compression-side chamber R2, and by moving axially relative to the cylinder 1, the piston 3 can expand one of the extension-side chamber R1 and the compression-side chamber R2 while contracting the other.

[0028] The piston 3 is also provided with an extension-side damping valve 7 and a check valve 8. The extension-side damping valve 7 only allows fluid to flow from the extension-side chamber R1 to the compression-side chamber R2, while providing resistance to the fluid flow. The check valve 8 only allows fluid to flow from the extension-side chamber R1 to the compression-side chamber R2, and closes to block the fluid flow from the compression-side chamber R2 to the extension-side chamber R1.

[0029] Next, the valve V includes a valve seat member 10 having an annular valve seat 10e, a valve body 11 that seats and disengages from the annular valve seat 10e, a spring 12 that urges the valve body 11 toward the annular valve seat 10e, and a spring bearing 13.

[0030] As shown in FIGS. 1 and 2, the valve seat member 10 is disk-shaped and includes: a flange 10a provided on the outer periphery and abutting the right end of the cylinder 1 in FIG. 2; a protruding portion 10b protruding from the center of the left end toward the compression-side chamber R2; a port 10c opening at the left end of the protruding portion 10b; a valve hole 10d opening at the right end, communicating with the port 10c and having an inner diameter larger than that of the port 10c; an annular valve seat 10e formed by the bottom of the valve hole 10d at which the port 10c opens; and a suction passage 10f provided outer periphery of the valve hole 10d and penetrating from the left end to the right end. The valve seat member 10 closes the right end of the cylinder 1 in FIG. 1 and faces the piston rod 2 in the axial direction.

[0031] The port 10c is a circular hole that opens from the center of the left end of the protrusion 10b in FIG. 2 and extends toward the right end in the left-right direction in FIG. 2, which corresponds to the axial direction of the valve seat member 10. Note that the port 10c does not have to be located at the center of the protrusion 10b, but locating it in the center facilitates machining when forming it by cutting. The valve hole 10d opens from the center of the right end of the valve seat member 10 in FIG. 2 so as to be coaxial with the port 10c and communicates with the port 10c. Note that the valve hole 10d does not have to be located coaxially with the port 10c, but locating it in the center of the valve seat member 10, like the port 10c, facilitates machining when forming it by cutting. The port 10c opens at the bottom of the valve hole 10d, and the flat bottom of the valve hole 10d surrounds the opening of the port 10c to form an annular valve seat 10e.

[0032] 2 of the flange 10a, and the legs 10g abut against the left end of the bottom cap 6, so that the space C between the valve seat member 10 and the bottom cap 6 is communicated with the tank T through the legs 10g, 10g. As shown in FIG. 1, when the valve seat member 10 is fitted onto the inner periphery of the left end of the cylinder 1 in FIG. 1, the flange 10a abuts against the left end of the cylinder 1 in FIG. 1 and the legs 10g abut against the left end of the bottom cap 6 in FIG. 1, and the valve seat member 10 is sandwiched between the cylinder 1 and the bottom cap 6 and fixed inside the outer tube 4.

[0033] 2, the valve seat member 10 is provided with a diagonal passage 10h that opens from the outer circumferential side of the valve orifice 10d, extends diagonally with respect to the axial direction, and leads into the valve orifice 10d, communicating the compression side chamber R2 with the space C via the diagonal passage 10h, the valve orifice 10d, and the port 10c. Since the space C is in communication with the tank T, the port 10c, the valve orifice 10d, and the diagonal passage 10h form a compression side damping passage P that communicates the compression side chamber R2 with the tank T. In addition, the suction passage 10f is parallel to the compression side damping passage P and communicates the compression side chamber R2 with the tank T.

[0034] The suction check valve 9 includes an annular valve element 9a slidably mounted on the outer periphery of the protrusion 10b at the left end of the valve seat member 10 in FIG. 1 to open and close the suction passage 10f, a spring retainer 9b attached to the outer periphery of the tip of the protrusion 10b, and a conical coil spring 9c interposed between the annular valve element 9a and the spring retainer 9b. When the suction check valve 9 moves away from the valve seat member 10 to open the suction passage 10f, it allows liquid to flow from the tank T toward the pressure-side chamber R2. When liquid attempts to pass through the suction passage 10f from the pressure-side chamber R2 toward the tank T, it seats on the valve seat member 10 to block the suction passage 10f and prevent the flow of liquid. Thus, the suction check valve 9 configures the suction passage 10f as a one-way passage that only allows liquid to flow from the tank T toward the pressure-side chamber R2.

[0035] The valve element 11 is inserted into the valve hole 10d so as to be movable in the left-right direction in Figure 2, which is the axial direction, and is equipped with a sliding contact portion 11a that is slidably inserted into the inner periphery of the port 10c, a disk-shaped seat portion 11b that is connected to the rear end of the sliding contact portion 11a and seats and lifts off from the annular valve seat 10e, and a guide portion 11c that is connected to the rear end of the seat portion 11b.

[0036] The sliding contact portion 11a includes a base portion 11a1 protruding from the center of the left end of the seat portion 11b in Figure 2, a pair of flow path forming bodies 11a2 and 11a3 connected to the base portion 11a1, rising toward the axial direction of the valve body 11 and facing each other, and a reinforcing portion 11a4 provided between the flow path forming bodies 11a2 and 11a3.

[0037] Base 11a1 is disk-shaped and protrudes from the center of the left end of seat 11b in Fig. 2. Flow path formers 11a2 and 11a3 are connected to the left end of base 11a1 in Fig. 2. As shown in Fig. 3, when viewed from the axial direction, their outer peripheral surfaces are curved surfaces that are flush with the outer peripheral surface of base 11a1, and their inner surfaces are flat except for the base ends. As shown in Fig. 2, they rise perpendicularly to seat 11b with their inner surfaces facing each other. As shown in Fig. 2, the width of the base ends of flow path formers 11a2 and 11a3 gradually increases toward base 11a1 when viewed from the side, and the inner peripheral surfaces of the base ends of flow path formers 11a2 and 11a3 are connected to form a curved surface.

[0038] As shown in FIG. 3, the reinforcing portions 11a4 are provided perpendicular to the inner peripheral surfaces of the flow path forming bodies 11a2 and 11a3, and are integrally connected to each other at the center portions over the entire axial length of the flow path forming bodies 11a2 and 11a3.

[0039] 3, when the sliding contact portion 11a is viewed from the axial direction, the flow path forming bodies 11a2, 11a3 and the reinforcing portion 11a4 form an H-shape, and the reinforcing portion 11a4 connects the flow path forming bodies 11a2, 11a3, which are spaced apart on the left and right, thereby increasing the bending rigidity of the entire sliding contact portion 11a. If the sliding contact portion 11a is likened to an H-shaped steel, the flow path forming bodies 11a2, 11a3 correspond to the flanges of the H-shaped steel, and the reinforcing portion 11a4 corresponds to the web of the H-shaped steel. Compared to a structure in which the flow path forming bodies 11a2, 11a3 rise from the seat portion 11b independently of each other without the reinforcing portion 11a4, the bending rigidity of the sliding contact portion 11a, which connects the flow path forming bodies 11a2, 11a3 to each other with the reinforcing portion 11a4, is significantly improved. Grooves 11a5 and 11a6 formed between the flow path forming bodies 11a2 and 11a3 form flow paths that allow the passage of liquid passing through the port 10c.

[0040] In the valve V of this embodiment, as shown in Fig. 2, the ratio of the width W2 of grooves 11a5 and 11a6 that form the flow paths to the radial width W1 of sliding contact portion 11a is 1 / 3 or more, ensuring a large flow path area. Also, as shown in Fig. 2, the ratio of the total length L of sliding contact portion 11a to the radial width W1 of sliding contact portion 11a, that is, the ratio of the length to the diameter, is 1 or more. As the ratio of the width W2 of grooves 11a5 and 11a6 that form the flow paths to the radial width W1 of sliding contact portion 11a increases, the flow path area increases but the bending rigidity of sliding contact portion 11a tends to decrease, and as the ratio of the length to the diameter of sliding contact portion 11a increases, the bending rigidity tends to decrease. Therefore, if a large flow path area is ensured and the length of the sliding contact portion 11a is increased, the bending rigidity of the sliding contact portion 11a decreases, the natural frequency decreases, and radial lateral vibrations become more likely to be excited. However, in the valve V of this embodiment, by providing a reinforcing portion 11a4, the bending rigidity of the sliding contact portion 11a in the valve body 11 is increased while ensuring the flow path area.

[0041] The sliding contact portion 11a configured in this manner is inserted into the port 10c, and the outer peripheral surface of the base 11a1 and the outer peripheral surfaces of the flow path formation bodies 11a2 and 11a3 are in sliding contact with the inner peripheral surface of the port 10c. Therefore, by slidably inserting the sliding contact portion 11a into the port 10c, the valve element 11 can move smoothly in the left-right direction in FIG. 2, which is the axial direction, without any axial wobble relative to the valve seat member 10.

[0042] The seat portion 11b is disk-shaped and connected to the right end in Fig. 2, which is the rear end of the sliding contact portion 11a, and has an outer diameter larger than that of the sliding contact portion 11a and smaller than the inner diameter of the valve hole 10d. The seat portion 11b faces the annular valve seat 10e of the valve seat member 10 in the axial direction, and as the valve element 11 moves axially within the valve hole 10d, the left end face in Fig. 2 is seated on and separated from the annular valve seat 10e. When the seat portion 11b is seated on the annular valve seat 10e, the valve element 11 blocks the port 10c and cuts off communication between the compression-side chamber R2 and the tank T.

[0043] The guide portion 11c is cylindrical and connected to the right end of the seat portion 11b in Fig. 2, and the outer diameter of the guide portion 11c is smaller than that of the seat portion 11b. The spring bearing 13 includes a cylindrical spring guide 13a and a flange 13b with a threaded portion on the outer periphery provided on the outer periphery of the right end in Fig. 2, which is the rear end of the spring guide 13a, and is attached to the valve seat member 10 by being screwed to the inner periphery of the right end in Fig. 2 of the valve hole 10d of the valve seat member 10.

[0044] The overall length of the sliding contact portion 11a in the axial direction is longer than the overall length of the port 10c of the valve seat member 10, and when the seat portion 11b is seated on the annular valve seat 10e of the valve seat member 10, the tip of the sliding contact portion 11a protrudes into the compression-side chamber R2, which is located on the left side of the port 10c in Figure 2. In this way, in the valve V of this embodiment, by reducing the thickness of the valve seat member 10 from the annular valve seat 10e to the left end of the protruding portion 10b in Figure 2, even if the axial length of the port 10c of the valve seat member 10 is shortened, it is possible to prevent the valve disc 11 from retracting and separating from the annular valve seat 10e and the sliding contact portion 11a from coming out of the port 10c.

[0045] 2, which is the end opposite the valve seat of seat portion 11b of valve element 11, and flange 13b of spring bearing 13, spring 12 is interposed in a compressed state and biases valve element 11 toward annular valve seat 10e. Guide portion 11c of valve element 11 is fitted into the inner periphery of spring 12 at the left end in FIG. 2, and spring guide 13a of spring bearing 13 is fitted into the inner periphery of spring 12 at the right end in FIG. 2, and spring 12 is guided by guide portion 11c and spring guide 13a, so that spring 12 can expand and contract without becoming eccentric or buckling relative to valve element 11.

[0046] In the valve V configured as described above, the spring bearing 13 is threadedly connected to the valve seat member 10, and by rotating the spring bearing 13, the attachment position of the spring bearing 13 within the valve hole 10d of the valve seat member 10 can be changed, thereby adjusting the biasing force that the spring 12 applies to the valve disc 11. The valve disc 11 is biased in a direction away from the annular valve seat 10e by the pressure of the compression-side chamber R2 acting within the port 10c, so by changing the position of the spring bearing 13 relative to the valve hole 10d, the biasing force that the spring 12 applies to the valve disc 11 can be adjusted, and the magnitude of the pressure in the compression-side chamber R2 required for the valve disc 11 to open can be adjusted.

[0047] In addition, in this embodiment, when the entire sliding contact portion 11a is inserted into the port 10c, the outer peripheral surface of the base portion 11a1 faces the inner peripheral surface of the port 10c, and the left end face of the seat portion 11b in Figure 2 seats on the annular valve seat 10e. When the valve element 11 seats on the annular valve seat 10e in this manner, the port 10c is closed, and communication between the compression-side chamber R2 and the tank T through the compression-side damping passage P is blocked.

[0048] Furthermore, even if the seat 11b of the valve element 11 moves away from the annular valve seat 10e, when the base 11a1 is inserted into the port 10c, the outer peripheral surface of the base 11a1 faces the inner peripheral surface of the port 10c, so that the port 10c remains closed. On the other hand, when the seat 11b of the valve element 11 moves away from the annular valve seat 10e and the base 11a1 also moves completely outside the port 10c, the port 10c and the valve hole 10d communicate with each other through the grooves 11a5 and 11a6, so that the valve element 11 opens and opens the port 10c, so that the compression-side chamber R2 and the tank T communicate with each other through the compression-side damping passage P.

[0049] In this way, the base 11a1 sets a dead zone within which the valve does not communicate between the compression side chamber R2 and the tank T even when the valve element 11 is only slightly separated from the annular valve seat 10e, and the valve does not open even when the valve element 11 is retracted from the annular valve seat 10e. By providing the base 11a1 in this way, the valve can be reliably closed when the valve element 11 is seated on the annular valve seat 10e, but if there is no need to provide a dead zone, the base 11a1 does not need to be provided, and the valve element 11 may have a structure in which the flow path forming bodies 11a2 and 11a3 rise directly from the seat portion 11b.

[0050] To manufacture the sliding contact portion 11a of such a valve disc 11, two parallel grooves 11a5, 11a6 are formed in a cylindrical base material by end milling, thereby easily forming the flow path forming bodies 11a2, 11a3 and the reinforcing portion 11a4 that form an H-shape when viewed from the axial direction. When grooves 11a5, 11a6 are cut into the side portions of the base material by moving a tool axially from the tip of the base material, curved surfaces are formed at the base portions of the flow path forming bodies 11a2, 11a3. However, when grooves 11a5, 11a6 are formed by moving the tool radially toward the base material, as in the valve disc 11 in the valve V1 of the first modified example of one embodiment shown in FIG. 4, the thickness of the base portion of the reinforcing portion 11a4 relative to the flow path forming bodies 11a2, 11a3 is increased, resulting in a curved side surface of the reinforcing portion 11a4, while the inner surfaces of the flow path forming bodies 11a2, 11a3 are flat along their entire lengths. Even in this case, the provision of the reinforcing portion 11a4 improves the bending rigidity of the sliding contact portion 11a compared to when the sliding contact portion 11a is formed by only the flow path forming bodies 11a2, 11a3 or the flow path forming bodies 11a2, 11a3 and the base portion 11a1.

[0051] Valve V comprises a spring-mass system consisting of a valve disc 11 and a spring 12. The valve disc 11 can move in the axial direction (left and right in FIG. 2). If the mass of the valve disc 11 is M and the spring constant of the spring 12 is K, the natural frequency of the spring-mass system in valve V is (K / M). 1 / 2 / 2π.

[0052] Furthermore, the sliding contact portion 11a has grooves 11a5 and 11a6 for forming a flow path, and when the flow path is enlarged, the sliding contact portion 11a behaves as a spring, so when the valve V is opened and a part of the sliding contact portion 11a is inserted into the port 10c of the valve seat member 10, not only does the valve element 11 vibrate in the axial direction, but the part of the sliding contact portion 11a that protrudes from the port 10c into the valve hole 10d behaves as a spring, causing the seat portion 11b and guide portion 11c of the valve element 11 to vibrate in the radial direction, generating a resonance mode. In this way, the natural frequency of the valve element 11 when the sliding contact portion 11a is viewed as a spring is calculated from the bending rigidity k of the sliding contact portion 11a and the mass m of the seat portion 11b and guide portion 11c of the valve element 11, as follows: (k / m) 1 / 2 In the valve V of this embodiment, the natural frequency of the sliding contact portion 11a is set to be higher than the natural frequency of the spring-mass system, and can be expressed as (k / m) 1 / 2 >(K / M) 1 / 2 is set to hold.

[0053] The valve V and the damper D are configured as described above, and their operations will be described below. First, the operation when the damper D extends will be described. When the damper D performs the extension operation, the piston 3 moves leftward in FIG. 1 relative to the cylinder 1, compressing the expansion-side chamber R1 while expanding the contraction-side chamber R2.

[0054] The compressed liquid in the extension-side chamber R1 pushes open the extension-side damping valve 7, passes through the extension-side damping valve 7, and moves to the compression-side chamber R2. When the damper D extends, the piston rod 2 retracts from the cylinder 1, causing a shortage of hydraulic oil in the compression-side chamber R2 by the volume of the piston rod 2 retracted from the cylinder 1. Therefore, the suction check valve 9 opens and this shortage of hydraulic oil is supplied from the tank T to the compression-side chamber R2 via the suction passage 10f.

[0055] Therefore, the pressure in the compression-side chamber R2 becomes approximately equal to the pressure in the tank T, while the pressure in the extension-side chamber R1 becomes higher than the pressure in the compression-side chamber R2 due to the extension-side damping valve 7. The high pressure in the extension-side chamber R1 acts on the left end face of the piston 3 in FIG. 1, and the tank pressure acts on the right end face of the piston 3 in FIG. 1, so the damper D generates a damping force that prevents the piston 3 from moving leftward in FIG. 1 relative to the cylinder 1, that is, a damping force that prevents the extension operation.

[0056] Next, when the damper D contracts, the piston 3 moves to the right in FIG. 1 inside the cylinder 1, compressing the compression-side chamber R2 while expanding the extension-side chamber R1. Liquid moves from the compressed compression-side chamber R2 to the extension-side chamber R1 through the check valve 8, so the pressures in the extension-side chamber R1 and the compression-side chamber R2 become approximately equal. When the damper D contracts, the piston rod 2 enters the cylinder 1, and the liquid in the cylinder 1 becomes excessive by the volume of the piston rod 2 entering the cylinder 1. When the pressure in the cylinder 1 reaches the opening pressure of the valve V due to the entry of the piston rod 2 into the cylinder 1, the valve V opens, connecting the compression-side chamber R2 and the tank T via the compression-side damping passage P.

[0057] Therefore, when the damper D contracts, the valve V applies resistance to the flow of liquid from inside the cylinder 1 toward the tank T, causing both the pressure in the extension-side chamber R1 and the pressure in the compression-side chamber R2 to increase. As described above, when the damper D contracts, the pressure in the extension-side chamber R1 and the pressure in the compression-side chamber R2 become approximately equal, but the right end face of the piston 3 that receives the pressure in the compression-side chamber R2 is larger than the left end face that receives the pressure in the extension-side chamber R1 by the cross-sectional area of ​​the piston rod 2, so the damper D generates a damping force that prevents the piston 3 from moving rightward in FIG. 1 relative to the cylinder 1, that is, a damping force that prevents the contraction operation.

[0058] In the valve V of this embodiment, the ratio of the width of the flow path to the radial width of the sliding contact portion 11a is 1 / 3 or more, so that a large flow path area can be ensured and the pressure override for the flow rate passing through can be reduced when the valve is open. As a result, as shown in FIG. 5, the damping force characteristics during the contraction operation of the damper D are such that when the valve V is opened, the damper speed in the contraction direction of the damper D increases and even if the flow rate increases, the pressure override is small and the rate of increase in the damping force relative to the increase in the damper speed can be reduced.

[0059] Furthermore, when the valve V opens, the sliding contact portion 11a moves from within the port 10c of the valve seat member 10 into the valve hole 10d, and a portion of the sliding contact portion 11a is inserted into the port 10c. As a result, the seat portion 11b and the guide portion 11c of the valve body 11 are elastically supported by the sliding contact portion 11a, and they tend to vibrate laterally. However, since the natural frequency of the valve body 11 when viewed as a spring is greater than the natural frequency of the spring-mass system of the valve body 11 and the spring 12, radial vibration of the valve body 11 is not excited even if the valve body 11 vibrates in the axial direction, and vibration of the valve body 11 itself is suppressed.

[0060] The inner diameter of the relief hole 2d opening from the tip of the piston rod 2 is larger than the outer diameter of the sliding contact portion 11a of the valve disc 11, the axial length of the relief hole 2d is longer than the maximum protrusion length of the sliding contact portion 11a from the port 10c toward the compression-side chamber R2 when the valve disc 11 is seated on the annular valve seat 10e, and the relief hole 2d opens at a position directly opposite and concentric with the port 10c in the axial direction with respect to the piston rod 2. Therefore, even when the damper D is fully contracted and the piston rod 2 is closest to the valve seat member 10, and the tip of the sliding contact portion 11a of the valve disc 11, which is the left end in Figure 2, protrudes from the port 10c toward the compression-side chamber R2, the sliding contact portion 11a is simply inserted into the relief hole 2d, and the piston rod 2 and the valve disc 11 do not come into contact with each other.

[0061] In order to prevent the tip of the piston rod 2 from interfering with the protruding portion 10b of the valve seat member 10 when the damper D is fully contracted, it is sufficient to thin the thickness of the portion from the annular valve seat 10e of the valve seat member 10 in the valve V to the left end in FIG. 1, which is the tip of the protruding portion 10b. However, since thinning the thickness shortens the port 10c, if the axial length of the sliding contact portion 11a of the valve element 11 is also shortened in accordance with the shortened overall length of the port 10c, the amount of retraction of the valve element 11 from the valve seat member 10 required for the entire sliding contact portion 11a to come out of the port 10c becomes smaller, and so the sliding contact portion 11a becomes more likely to come out of the port 10c. In the valve V of this embodiment, the sliding contact portion 11a is in sliding contact with the inside of the port 10c, thereby guiding the axial movement of the valve element 11 relative to the valve seat member 10. Therefore, if the valve element 11 retreats from the annular valve seat 10e and the sliding contact portion 11a comes out of the port 10c, the valve element 11 will vibrate radially, and even if it tries to seat on the annular valve seat 10e again, the sliding contact portion 11a will not be able to be inserted into the port 10c, which may prevent the valve V from closing. However, if the alignment of the valve element 11 with the valve seat member 10 is achieved by sliding the outer periphery of the seat portion 11b against the inner periphery of the valve hole 10d, additional processing of the valve seat member 10 is required. If the alignment of the valve element 11 with the valve seat member 10 is achieved using the guide portion 11c and the spring bearing 13, dimensional errors may make it difficult to insert the sliding contact portion 11a into the port 10c, which may increase the frictional resistance between the sliding contact portion 11a and the port 10c. This requires high processing precision, which results in increased costs.

[0062] For the reasons described above, in the valve V of this embodiment, even if the thickness from the annular valve seat 10e of the valve seat member 10 to the left end in FIG. 1, which is the tip of the protruding portion 10b, is thinned, the overall length is ensured to be such that the sliding contact portion 11a does not slip out of the port 10c. However, a relief hole 2d is provided at the tip of the piston rod 2, so that even when the damper D is fully contracted, the sliding contact portion 11a is simply inserted into the relief hole 2d, and the piston rod 2 and the valve body 11 do not come into contact with each other.

[0063] As described above, in the damper D of this embodiment, even if the thickness from the annular valve seat 10e of the valve seat member 10 in the valve V to the left end of the protruding portion 10b is thinned, contact between the piston rod 2 and the sliding contact portion 11a of the valve body 11 can be avoided. Therefore, the stroke length of the damper D can be secured by widening the movement limit of the piston rod 2 toward the contraction side of the cylinder 1 in FIG. 1, and the sliding contact portion 11a can be prevented from coming out of the port 10c even if the valve body 11 retracts from the annular valve seat 10e.

[0064] As described above, the valve V of this embodiment comprises a valve seat member 10 having a port 10c and an annular valve seat 10e arranged around the outlet end of the port 10c, a valve disc 11 that can move toward and away from the annular valve seat 10e and seat on and off the annular valve seat 10e, and a spring 12 that urges the valve disc 11 toward the annular valve seat 10e, and the valve disc 11 has a sliding contact portion 11a that is slidably inserted into the inner periphery of the port 10c, and a disk-shaped seat portion 11b that is connected to the rear end of the sliding contact portion 11a and seated on and off the annular valve seat 10e, and the natural frequency of the valve disc 11 when the sliding contact portion 11a is viewed as a spring is higher than the natural frequency of the spring-mass system consisting of the valve disc 11 and the spring 12.

[0065] With the valve V configured in this manner, the natural frequency of the valve body 11 when the sliding contact portion 11a is viewed as a spring is greater than the natural frequency of the spring-mass system of the valve body 11 and the spring 12. Therefore, when the valve V opens, even if the valve body 11 vibrates in the axial direction, radial vibration of the valve body 11 is not excited, and vibration of the valve body 11 itself can be suppressed, thereby preventing noise generation and generating a stable damping force.

[0066] In addition, in the valve V of this embodiment, the sliding contact portion 11a is provided with a pair of flow path forming bodies 11a2, 11a3 that rise from the seat portion 11b, face each other, and slide against the inner circumference of the port 10c to form a flow path between them, and a reinforcing portion 11a4 provided between the flow path forming bodies 11a2, 11a3, and the ratio of the width of the flow path to the radial width of the sliding contact portion 11a is 1 / 3 or more.

[0067] With the valve V configured in this manner, the ratio of the width of the flow path to the radial width of the sliding contact portion 11a is set to 1 / 3 or more, ensuring a large flow path area and reducing pressure override on the flow rate when the valve is open, while providing the reinforcing portion 11a4 between the flow path formation bodies 11a2, 11a3 means that the flow path formation bodies 11a2, 11a3 are integrated rather than independent of each other, thereby increasing the bending rigidity of the sliding contact portion 11a and suppressing radial vibration of the valve element 11. Therefore, with the valve V configured in this manner, it is possible to prevent noise generation, generate a stable damping force, and achieve good relief characteristics with little pressure override.

[0068] Furthermore, the damper D of this embodiment includes a cylinder 1, a piston rod 2 inserted into the cylinder 1 so as to be movable in the axial direction, a ring-shaped piston 3 inserted into the cylinder 1 so as to be movable and connected to the outer periphery of the piston rod 2, and a valve V, wherein the valve seat member 10 closes the end of the cylinder 1 and faces the tip of the piston rod 2 in the axial direction, and the piston rod 2 has an escape hole 2d directly opposite the port 10c in the axial direction and allowing the sliding portion 11a of the valve body 11 to be inserted.

[0069] According to the damper D configured in this manner, the piston rod 2 is provided with an escape hole 2d that opens from the tip and allows insertion of the sliding contact portion 11a. Therefore, even if the thickness from the annular valve seat 10e of the valve seat member 10 in the valve V to the left end of the protruding portion 10b is thinned and the entire length of the sliding contact portion 11a is ensured to be such that it does not slip out of the port 10c, it is possible to avoid contact between the piston rod 2 and the sliding contact portion 11a of the valve body 11. As a result, the movement limit of the piston rod 2 toward the contraction side when the damper D contracts can be expanded to the right of the cylinder 1 in FIG. 1, and the stroke length of the damper D can be ensured.

[0070] 6, the valve body 11 may be provided with a hole 11a7 opening from the tip of the reinforcing portion 11a4, a hole 11c1 opening from the rear end of the guide portion 11c, and an orifice 11d connecting the hole 11a7 and the hole 11c1. In this way, until the valve V2 opens when the damper D is contracting, the liquid moves from the compression-side chamber R2 to the tank T through the orifice 11d. Therefore, as shown by the dashed line in FIG. 5, when the damper D contracts at a low speed, a damping force is generated by the orifice 11d. When the damper D contracts at a high speed, the valve V2 opens and the valve V2 generates a damping force as shown by the solid line in FIG. 5.

[0071] Furthermore, as in a valve V3 of a third modified example of an embodiment shown in FIG. 7, arc-shaped recesses 11a8, 11a9 may be provided on the inner sides of a pair of flow path formation bodies 11a2, 11a3 facing each other in the sliding contact portion 11a, and a cylindrical reinforcing portion 11a10 may be fitted into the recesses 11a8, 11a9. With the valve V3 configured in this manner, providing the reinforcing portion 11a10 between the flow path formation bodies 11a2, 11a3 allows the flow path formation bodies 11a2, 11a3 to be integrated rather than independent of each other, thereby increasing the bending rigidity of the sliding contact portion 11a and suppressing radial vibration of the valve disc 11. Therefore, with the valve V3 configured in this manner, it is possible to prevent noise generation, generate a stable damping force, and achieve good relief characteristics with little pressure override.

[0072] 8, the sliding contact portion 11a may be cylindrical and have four or more grooves 11a11, 11a12, 11a13, and 11a14 extending from the front end to the rear end on the outer periphery to form a flow path, as in the valve V4 of a fourth modified example of one embodiment. In this case, by providing three or more grooves 11a11, 11a12, 11a13, and 11a14 circumferentially distributed on the outer periphery of the sliding contact portion 11a, the central portion of the sliding contact portion 11a can be solidified while ensuring a sufficient flow path area, thereby improving bending rigidity. In this way, in the valve V4 of the fourth modified example of one embodiment, the sliding contact portion 11a is cylindrical and has three or more grooves 11a11, 11a12, 11a13, and 11a14 extending from the front end to the rear end on the outer periphery to form a flow path, which prevents noise generation, generates a stable damping force, and achieves good relief characteristics with little pressure override.

[0073] 9, the sliding contact portion 11a may have a two-flat shape, as in a valve V5 of a fifth modified example of one embodiment. In this case, the outer peripheral shape of the sliding contact portion 11a has a two-flat shape, so that the width of the sliding contact portion 11a can be secured while ensuring the flow path area, thereby improving bending rigidity. Therefore, the valve V5 of the fifth modified example of one embodiment can prevent noise generation, generate a stable damping force, and achieve good relief characteristics with little pressure override.

[0074] It goes without saying that the valves V, V1, V2, V3, V4, and V5 can be applied to the damper D described above, but they can also be applied to dampers other than those having the structure described above. Furthermore, the valves V, V1, V2, V3, V4, and V5 may be provided not only in the base valve portion as in the damper D described above, but also in the piston portion using the piston as a valve seat member, and the installation location can be changed as desired depending on the structure of the damper to be installed.

[0075] Although the preferred embodiment of the present invention has been described in detail, modifications, variations and changes can be made thereto without departing from the scope of the appended claims. [Explanation of symbols]

[0076] 10···Valve seat member, 10c···Port, 10e···Annular valve seat, 11···Valve body, 11a···Sliding contact portion, 11a2, 11a3···Flow path formation body, 11a4, 11a10···Reinforcing portion, 11a11, 11a12, 11a13, 11a14···Groove, 12···Spring, V, V1, V2, V3, V4, V5··Valve

Claims

1. a valve seat member having a port and an annular valve seat disposed around the outlet end of the port; a valve body that is movable toward and away from the annular valve seat and that seats and leaves the annular valve seat; a spring that biases the valve body toward the annular valve seat, the valve element has a sliding contact portion slidably inserted into an inner periphery of the port, and a disk-shaped seat portion connected to a rear end of the sliding contact portion and adapted to seat on and separate from the annular valve seat, The natural frequency of the valve body when the sliding contact portion is viewed as a spring is higher than the natural frequency of a spring-mass system consisting of the valve body and the spring. A valve characterized by:

2. The sliding contact portion is a pair of flow path forming bodies that rise from the seat portion, face each other, and come into sliding contact with an inner periphery of the port to form a flow path therebetween; a reinforcing portion provided between the flow path forming bodies, The ratio of the width of the flow path to the radial width of the sliding contact portion is 1 / 3 or more.

2. The valve of claim 1.

3. The sliding contact portion is It is cylindrical and has three or more grooves on the outer periphery that extend from the front end to the rear end to form flow paths.

2. The valve of claim 1.

4. A cylinder; a piston rod inserted into the cylinder so as to be axially movable; a piston that is annular and movably inserted into the cylinder and is connected to an outer periphery of the piston rod; and the valve according to any one of claims 1 to 3, the valve seat member closes an end of the cylinder and faces a tip of the piston rod in the axial direction; The piston rod has a relief hole that faces the port in the axial direction and allows the sliding contact portion of the valve body to be inserted. A damper characterized by:

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