Valve and buffer

Abstract

A valve (V) is provided with: a valve seat member (10) having a port (10c) and an annular valve seat (10e) provided around the outlet end of the port (10c); a valve body (11) that can be brought close to or away from the annular valve seat (10e) and is seated on the annular valve seat (10e); and a spring (12) that applies a force to the valve body (11) toward the annular valve seat (10e), the valve body (11) having a sliding contact section (11a) that is slidably inserted into the inner periphery of the port (10c), and a disc-shaped seat section (11b) that is connected to the rear end of the sliding contact section (11a) and is seated away from the annular valve seat (10e). The natural vibration frequency of the valve body (11) is higher than the natural vibration frequency of a spring mass system composed of the valve body (11) and the spring (12) when the sliding contact part (11a) is regarded as a spring.

Description

Technical Field

[0001] This invention relates to a valve and a damper. Background Technology

[0002] Valves, such as those used in devices like buffers or cylinders, create resistance to the flow of hydraulic oil that accompanies the expansion and contraction of the buffer, thereby generating a damping force, or they open the valve when the pressure in the buffer's working chamber reaches the valve opening pressure to prevent excessive pressure in the working chamber.

[0003] The valve described above, for example as shown in patent JP2002-295565A, comprises: a piston inserted into a cylinder of a multi-cylinder buffer, dividing the interior of the cylinder into a rod-side chamber and a piston-side chamber; a housing, comprising a valve housing disposed at the end of the cylinder; an annular valve seat disposed on the inner circumference of a valve hole in the housing; a valve body that is axially movable and inserted into the valve hole, and sits on the annular valve seat; and a helical spring that applies a force to the valve body toward the annular valve seat.

[0004] Furthermore, the valve body in the valve has a front end portion that can be slidably inserted into a small-diameter portion forming a port on the valve hole, and a sitting portion that connects to the rear end of the front end portion and sits on an annular valve seat. The front end portion has a slit that opens from the front end and is bifurcated, allowing a large flow rate to pass through when the valve is opened.

[0005] In a valve with the structure described above, when the pressure on the port side reaches the opening pressure, the valve body is pushed by the pressure and moves away from the annular valve seat, opening the valve and allowing hydraulic oil to flow through the valve orifice via the slit. Summary of the Invention The problem that the invention aims to solve

[0006] In this type of conventional valve, when the seat part leaves the annular valve seat, a portion of the forked front end with a slit is inserted into the port, and the valve body is supported by the front end.

[0007] Furthermore, if a large flow rate is required when the valve is opened, the width of the slit needs to be increased. However, if the slit width is increased, the rigidity of the front end will decrease. When the valve is opened, the front end is supported by the outer shell, which will excite the valve body to vibrate in the radial and lateral directions. This will not only generate noise, but also cause the damping force to vibrate and become unstable.

[0008] Therefore, the present invention aims to provide a valve that can suppress lateral vibration of the valve body and generate a stable damping force, as well as a damper adapted to the valve. Solution for solving the problem

[0009] The valve of the present invention comprises: a valve seat component having a port and an annular valve seat disposed around the outlet end of the port; a valve body that can move closer to or further away from the annular valve seat and sit on the annular valve seat; and a spring that applies a force toward the annular valve seat to the valve body. The valve body has a sliding contact portion that is slidably inserted into the inner circumference of the port, and a circular plate-shaped seat portion connected to the rear end of the sliding contact portion and sitting on the annular valve seat. When the sliding contact portion is considered as a spring, the natural vibration frequency of the valve body is higher than the natural vibration frequency of the spring-mass system composed of the valve body and the spring.

[0010] According to the valve constructed in this way, since the natural vibration frequency of the valve body when the sliding contact part is regarded as a spring is greater than the natural vibration frequency of the valve body and the spring mass system, when the valve is opened, even if the valve body vibrates in the axial direction, it will not excite the radial vibration of the valve body, thereby suppressing the vibration of the valve body itself.

[0011] Furthermore, the buffer in this invention includes a cylinder, a piston rod that is axially movable into the cylinder, a piston that is annular and movable into the cylinder and connected to the outer periphery of the piston rod, a valve, a valve seat component that closes the end of the cylinder and is axially opposite to the front end of the piston rod, and the piston rod is provided with a clearance hole that is axially aligned with the port and allows the sliding contact portion of the valve body to be inserted.

[0012] According to the buffer constructed in this way, since the piston rod is provided with a clearance hole that opens from the front end and allows the sliding contact part to be inserted, even if the wall thickness of the valve from the annular valve seat of the valve seat component to the front end of the protrusion is reduced, it is ensured that the entire length of the sliding contact part will not come out of the port, and the piston rod can still avoid contact with the sliding contact part of the valve body, and the limit of the buffer's movement towards the contraction side of the piston rod when it contracts is expanded, thereby ensuring the stroke length of the buffer. Invention Effects

[0013] The valve and damper according to the present invention can suppress lateral vibration of the valve body and generate a stable damping force. Attached Figure Description

[0014] Figure 1 This is a longitudinal cross-sectional view of a valve buffer using one embodiment. Figure 2 This is an enlarged cross-sectional view of a valve according to one embodiment. Figure 3 This is a front view of the valve body in one embodiment of the valve. Figure 4 This is a perspective view of the valve body in a first variation of an embodiment. Figure 5 This is a schematic diagram of the damping force characteristics of a valve buffer during contraction, based on one embodiment. Figure 6 This is a cross-sectional view of the valve in a second variation of one embodiment. Figure 7 This is a cross-sectional view of the valve in the third variation of one embodiment. Figure 8 This is a perspective view of the valve body in the fourth variation of an embodiment. Figure 9 This is a perspective view of the valve body in a fifth variation of an embodiment. Detailed Implementation

[0015] The present invention will now be described based on the embodiments shown in the figures. One embodiment of the valve V is as follows: Figure 1 and Figure 2 As shown, it includes: a valve seat component 10 having an annular valve seat 10e, a valve body 11 seated on the annular valve seat 10e, and a spring 12 that applies a force toward the annular valve seat 10e to the valve body 11, which serves as the base valve in the buffer D and generates a compression-side damping force.

[0016] The following will describe in detail the various parts of valve V. The buffer D, which utilizes valve V, is as follows: Figure 1 As shown, it comprises: 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, simultaneously dividing the interior of the cylinder 1 into an elongated side chamber R1 filled with liquid and a compression side chamber R2; an outer tube 4 covering the outer periphery of the cylinder 1 and forming a liquid reservoir T between the outer tube and the cylinder 1 for storing liquid; and a guide 5, which is annular and seals the cylinder 1 and the outer tube 4. Figure 1 The left end of the cylinder simultaneously guides the axial movement of the piston rod 2 inserted in the inner circumference; valve V, which has a closing function for cylinder 1. Figure 1 The valve seat component 10 at the right end of the middle, and applies resistance to the liquid flow from the compression side chamber R2 to the storage tank T; bottom cover 6, which closes the outer pipe 4. Figure 1 The right end of the piston 3; the extension side damping valve 7, which is mounted on the piston 3; the check valve 8, which is mounted on the piston 3; and the suction check valve 9, which is mounted on the valve seat component 10.

[0017] Furthermore, the liquid in the elongation side chamber R1, the compression side chamber R2, and the reservoir T can be, for example, hydraulic oil, but water or an aqueous solution can also be used in addition to hydraulic oil. In addition to the liquid, the reservoir T is also filled with gas.

[0018] Cylinder 1 is cylindrical. Figure 1 An annular guide 5 is installed at the left end to close the opening at the left end, while... Figure 1A valve seat component 10 is installed at the right end to close the opening at the right end. The piston rod 2 is axially movable into the cylinder 1 via the inner circumference of the guide 5, so that... Figure 1 The left end of the cylinder protrudes outward from cylinder 1.

[0019] Furthermore, cylinder 1 is housed within outer tube 4. Outer tube 4's... Figure 1 The left end of the middle is closed by guide 5, at the same time Figure 1 The right end of the outer tube 4 is closed by the bottom cover 6. As described above, the left and right open ends of the outer tube 4 are closed by the guide 5 and the bottom cover 6 respectively, and the annular gap between the outer tube 4 and the cylinder 1 together form the liquid storage tank T.

[0020] When the guide 5 and the bottom cover 6 are fixed to the left and right ends of the outer tube 4 respectively, the cylinder 1 and the valve seat component 10 at the right end of the closed cylinder 1 are clamped by the guide 5 and the bottom cover 6, thereby fixing the cylinder 1 and the valve seat component 10 relative to the outer tube 4.

[0021] In addition, the piston rod 2 inserted into cylinder 1 Figure 1 The outer circumference of the right end of the piston rod 2 is connected to the piston 3 inserted into the cylinder 1, and the piston rod 2 protrudes out of the cylinder 1. Figure 1 A bracket (not shown) is provided on the left side for mounting the buffer D onto external equipment such as railway vehicles (not shown). Furthermore, although not shown, the bottom cover 6 also has a bracket for mounting the buffer D onto the external equipment; the buffer D can be mounted onto the external equipment using the brackets provided on the bottom cover 6 and the piston rod 2.

[0022] In addition, the piston rod 2 is equipped with a setting Figure 1 The right-hand side with a smaller outer diameter than the left side of the small diameter portion 2a, the stepped portion 2b formed at the junction between the small diameter portion 2a and the left side of the small diameter portion 2a, and the outer periphery of the small diameter portion 2a formed on the right side of the small diameter portion 2a. Figure 1 The threaded portion 2c on the front end of the middle right end and the clearance hole 2d opening at the front end of the small diameter portion 2a.

[0023] Furthermore, the piston 3 is annular and fits onto the outer circumference of the small-diameter portion 2a of the piston rod 2, and is fixed to the piston rod 2 by a nut 15 threadedly engaging with the threaded portion 2c of the small-diameter portion 2a. The piston 3 is inserted into the cylinder 1 in a manner where its outer circumference slides into contact with the inner circumference of the cylinder 1, and can move axially (i.e., together with the piston rod 2) relative to the cylinder 1. Figure 1 The piston moves in the left-right direction. The piston 3 divides the interior of the cylinder 1 into an elongation side chamber R1 and a compression side chamber R2. By moving axially relative to the cylinder 1, one of the elongation side chamber R1 and the compression side chamber R2 expands while the other shrinks.

[0024] In addition, piston 3 is equipped with an extension-side damping valve 7 and a check valve 8. The extension-side damping valve 7 only allows liquid to flow from the extension-side chamber R1 to the compression-side chamber R2, and applies resistance to the flow of this liquid. The check valve 8 only allows liquid to flow from the extension-side chamber R1 to the compression-side chamber R2, and closes the valve to prevent the flow of liquid from the compression-side chamber R2 to the extension-side chamber R1.

[0025] Furthermore, the valve V includes: a valve seat component 10 having an annular valve seat 10e, a valve body 11 seated on the annular valve seat 10e, a spring 12 that applies a force toward the annular valve seat 10e to the valve body 11, and a spring seat 13.

[0026] Valve seat component 10, such as Figure 1 and Figure 2 As shown, it is disc-shaped and has a feature disposed on its outer periphery and connected to cylinder 1. Figure 2 The cylinder 1 has a flange 10a abutting at its right end, a protrusion 10b protruding from the center of its left end toward the compression chamber R2, a port 10c opening from the left end of the protrusion 10b, a large-diameter valve hole 10d opening from the right end and communicating with the port 10c, and having an inner diameter larger than the port 10c, an annular valve seat 10e formed in the valve hole 10d from the bottom of the opening of the port 10c, and an intake passage 10f located closer to the outer periphery than the valve hole 10d and extending from the left end to the right end, thus sealing the cylinder 1. Figure 1 The right end of the piston rod is axially opposite to the piston rod 2.

[0027] Port 10c is a round hole, which extends from the protrusion 10b. Figure 2 The central opening at the left end and along the axial direction of the valve seat component 10 (i.e. Figure 2 It extends to the right end (in the left-right direction). Furthermore, the location of the port 10c is not limited to the center of the protrusion 10b, but if it is located in the center, it is easier to form by machining. Also, the valve hole 10d extends from the valve seat component 10... Figure 2 The valve seat 10e has a central opening at the right end, which communicates with port 10c and is coaxial with port 10c. Alternatively, the valve hole 10d may not be coaxial with port 10c, but it is easier to form by machining if it is located in the center of the valve seat component 10, just like port 10c. Port 10c opens at the bottom of valve hole 10d, and the flat bottom of valve hole 10d surrounds the opening of port 10c, thus forming an annular valve seat 10e.

[0028] Furthermore, the valve seat component 10 has a flange 10a Figure 2 The right end extends axially and abuts against the bottom cover 6. Figure 2 Multiple supports 10g at the left end of the valve seat assembly 10 are connected to the storage tank T via the space C between the valve seat assembly 10 and the bottom cover 6. Valve seat assembly 10 is as follows: Figure 1As shown, fitted into cylinder 1 Figure 1 When the inner circumference of the left end is reached, the flange 10a abuts against the cylinder 1. Figure 1 At the right end, the support leg 10g abuts against the bottom cover 6. Figure 1 The middle left end is clamped between the cylinder 1 and the bottom cover 6, thus being fixed inside the outer tube 4.

[0029] Furthermore, the valve seat component 10 also has an oblique passage 10h, which leads from... Figure 2 The right end is closer to the outer peripheral opening than the valve orifice 10d, and extends obliquely into the valve orifice 10d relative to the axial direction. It connects the compression-side chamber R2 and the space C via the oblique channel 10h, the valve orifice 10d, and the port 10c. Since the space C is connected to the reservoir T, the port 10c, the valve orifice 10d, and the oblique channel 10h form a compression-side damping channel P connecting the compression-side chamber R2 and the reservoir T. Furthermore, the suction channel 10f is parallel to the compression-side damping channel P, connecting the compression-side chamber R2 and the reservoir T.

[0030] The suction check valve 9 is configured to include: a part that is slidably mounted on the valve seat component 10. Figure 1 The annular valve body 9a, located on the outer periphery of the protrusion 10b at the left end, allows the suction passage 10f to be opened or closed. A spring bracket 9b is mounted on the outer periphery of the front end of the protrusion 10b. A conical helical spring 9c is installed between the annular valve body 9a and the spring bracket 9b. When the suction check valve 9 leaves the valve seat assembly 10 and opens the suction passage 10f, liquid is allowed to flow from the reservoir T to the compression chamber R2. When liquid flows from the compression chamber R2 to the reservoir T through the suction passage 10f, the suction check valve 9 sits on the valve seat assembly 10, blocking the suction passage 10f and thus preventing the flow of liquid. Therefore, the suction check valve 9 is configured to allow only one-way flow of liquid from the reservoir T to the compression chamber R2 via the suction passage 10f.

[0031] Valve body 11 in the axial direction (i.e. Figure 2 It is movably inserted into the valve hole 10d in the left-right direction, and has a sliding contact portion 11a that is slidably inserted into the inner periphery of the port 10c, a circular plate-shaped seat portion 11b that is connected to the rear end of the sliding contact portion 11a and sits on the annular valve seat 10e, and a guide portion 11c that is connected to the rear end of the seat portion 11b.

[0032] The sliding contact portion 11a is provided with the seat portion 11b Figure 2 The base 11a1 protruding from the center of the left end, a pair of flow path forming bodies 11a2 and 11a3 connected to the base 11a1 and erected in the axial direction of the valve body 11 and facing each other, and a reinforcing part 11a4 provided between the flow path forming bodies 11a2 and 11a3.

[0033] The base 11a1 is disc-shaped, and its base 11b is... Figure 2 The center of the left end protrudes. Flow path forming bodies 11a2 and 11a3 are interconnected at the base 11a1. Figure 2 Middle left end, such as Figure 3 As shown, when viewed axially, the outer peripheral surface is flush with the outer peripheral surface of the base 11a1, forming a curved surface, while the inner surface, except for the base end, is a flat surface, as... Figure 2 As shown, with the inner surfaces of both facing each other, they are erected vertically to the seat portion 11b. The base ends of the flow path forming bodies 11a2 and 11a3 are as follows: Figure 2 As shown, when viewed from the side, the width towards the base 11a1 gradually increases, and the inner peripheral surfaces of the base ends of the flow path forming bodies 11a2 and 11a3 are connected to each other to form a curved surface.

[0034] Strengthening part 11a4 Figure 3 As shown, it is vertically disposed on the inner peripheral surface of the flow path forming bodies 11a2 and 11a3, and integrally connected to the central part of the two along the entire axial length of the flow path forming bodies 11a2 and 11a3.

[0035] like Figure 3 As shown, when the sliding contact portion 11a is viewed axially, the flow path forming bodies 11a2 and 11a3, together with the reinforcing body 11a4, constitute an H-shaped structure. The reinforcing body 11a4 connects the left and right separate flow path forming bodies 11a2 and 11a3, thereby improving the overall bending stiffness of the sliding contact portion 11a. If the sliding contact portion 11a is likened to an H-beam, then the flow path forming bodies 11a2 and 11a3 are equivalent to the flanges of the H-beam, and the reinforcing body 11a4 is equivalent to the web of the H-beam. Compared with the structure where no reinforcing body 11a4 is provided and only the independent flow path forming bodies 11a2 and 11a3 stand upright from the seat portion 11b, the sliding contact portion 11a, which is connected by the reinforcing body 11a4, has a significantly improved bending stiffness. In addition, the grooves 11a5 and 11a6 formed between the flow path forming bodies 11a2 and 11a3 constitute a flow path that allows liquid to pass through the port 10c.

[0036] Furthermore, in valve V of this embodiment, as... Figure 2 As shown, the ratio of the width W2 of the grooves 11a5 and 11a6 constituting the flow path to the radial width W1 of the sliding contact portion 11a is more than 1 / 3, thereby ensuring a large flow path area. Furthermore, as... Figure 2As shown, the ratio of the total length L of the sliding contact portion 11a to its radial width W1 (i.e., the ratio of length to diameter) is 1 or more. The larger the ratio of the width W2 of the flow channel grooves 11a5 and 11a6 to the radial width W1 of the sliding contact portion 11a, the larger the flow path area. However, this also leads to a decrease in the bending stiffness of the sliding contact portion 11a, showing a trend where the larger the ratio of the length of the sliding contact portion 11a to its diameter, the lower its bending stiffness. Therefore, while ensuring a large flow path area, increasing the length of the sliding contact portion 11a will result in a decrease in the bending stiffness and natural frequency of the sliding contact portion 11a, making it easier to induce radial (i.e., lateral) vibration. However, in the valve V of this embodiment, by providing the reinforcing portion 11a4, the bending stiffness of the sliding contact portion 11a in the valve body 11 is improved while ensuring the flow path area.

[0037] The sliding contact portion 11a, configured in this way, is inserted into the interior of the port 10c, and sliding contact is achieved between the outer peripheral surface of the base 11a1 and the outer peripheral surfaces of the flow path forming bodies 11a2 and 11a3 and the inner peripheral surface of the port 10c. Thus, by slidably inserting the sliding contact portion 11a into the interior of the port 10c, the valve body 11 can move axially (i.e., without axial deflection relative to the valve seat member 10) along the axial direction. Figure 2 Smooth movement in the left and right directions.

[0038] The seat 11b is disc-shaped and is located at the rear end of the sliding contact portion 11a (i.e., Figure 2 The valve body 11 is connected to the right end of the valve seat 10, and its outer diameter is larger than the outer diameter of the sliding contact part 11a and smaller than the inner diameter of the valve hole 10d. It is axially opposite to the annular valve seat 10e of the valve seat component 10, and moves axially within the valve hole 10d via the valve body 11. Figure 2 The left end face of the valve 11b is seated on the annular valve seat 10e. When the seat 11b is seated on the annular valve seat 10e, the valve body 11 will block the port 10c, thereby cutting off the connection between the compression side chamber R2 and the liquid storage tank T.

[0039] The guide portion 11c is cylindrical, and it is connected to the seat portion 11b. Figure 2 The right end is connected, and its outer diameter is smaller than that of the seat 11b. The spring bracket 13 has a cylindrical spring guide 13a, which is located at the rear end of the spring guide 13a (i.e., Figure 2 The flange 13b, which has a threaded portion on the outer periphery of the right end of the valve seat component 10, is connected to the valve hole 10d of the valve seat component 10. Figure 2 The right end of the valve is connected by an inner circumferential thread, thereby mounting it on the valve seat component 10.

[0040] Furthermore, the axial length of the sliding contact portion 11a is greater than the axial length of the port 10c of the valve seat component 10. When the seat portion 11b is seated on the annular valve seat 10e of the valve seat component 10, the front end of the sliding contact portion 11a will protrude into the port 10c. Figure 2 Inside the compression side chamber R2 on the left side. As described above, in the valve V of this embodiment, by moving the valve seat component 10 from the annular valve seat 10e to the protrusion 10b... Figure 2 The wall thickness at the left end is reduced to ensure that even if the axial length of the port 10c of the valve seat component 10 is shortened, the sliding contact 11a is prevented from dislodging from the port 10c when the valve body 11 retracts from the annular valve seat 10e.

[0041] Spring 12 is clamped in a compressed state at the seat portion 11b of valve body 11 and the valve seat side end (i.e. Figure 2 The spring 12 is located between the flange 13b of the spring support 13 and the opposite side of the middle right end, and applies a force to the valve body 11 toward the annular valve seat 10e. Figure 2 The guide portion 11c of the valve body 11 is fitted onto the inner circumference of the middle left end, and the spring 12... Figure 2 The inner circumference of the right end is fitted with a spring guide portion 13a of a spring bracket 13. The spring 12 is guided by the guide portion 11c and the spring guide portion 13a, so that it can perform telescopic movement in a state of avoiding eccentricity or buckling relative to the valve body 11.

[0042] In the valve V constructed in this manner, the force exerted by the spring 12 on the valve body 11 can be adjusted by threading the spring bracket 13 to the valve seat component 10 and rotating the spring bracket 13 to change its installation position within the valve hole 10d of the valve seat component 10. Since the valve body 11 moves away from the annular valve seat 10e due to the pressure of the compression chamber R2 within the port 10c, the force exerted by the spring 12 on the valve body 11 can be changed by adjusting the position of the spring bracket 13 within the valve hole 10d, thereby adjusting the pressure of the compression chamber R2 required for the valve body 11 to open.

[0043] In this embodiment, when the sliding contact portion 11a is fully inserted into the interior of the port 10c, the outer peripheral surface of the base portion 11a1 faces the inner peripheral surface of the port 10c, and the seat portion 11b... Figure 2 The middle left end face sits on the annular valve seat 10e. Thus, when the valve body 11 sits on the annular valve seat 10e, the port 10c is closed, and the communication between the compression side chamber R2 and the liquid storage tank T through the compression side damping channel P is blocked.

[0044] Furthermore, when the seat 11b of the valve body 11 leaves the annular valve seat 10e, but the base 11a1 remains inserted inside the port 10c, the port 10c will remain closed because the outer circumferential surface of the base 11a1 is opposite to the inner circumferential surface of the port 10c. Conversely, when the seat 11b of the valve body 11 leaves the annular valve seat 10e and the base 11a1 is completely withdrawn from the port 10c, the port 10c and the valve hole 10d are connected through the grooves 11a5 and 11a6. At this time, the valve body 11 opens the valve and opens the port 10c, and the compression side chamber R2 is connected to the liquid storage tank T through the compression side damping channel P.

[0045] Thus, when the valve body 11 is only slightly away from the annular valve seat 10e, the base 11a1 cannot connect the compression side chamber R2 and the liquid storage tank T, thereby setting a range in which the valve body 11 will not open even when it retracts from the annular valve seat 10e, i.e., the non-sensitive zone. Thus, by providing the base 11a1 as described above, the valve can be reliably closed when the valve body 11 is seated on the annular valve seat 10e. However, when there is no need to set a non-sensitive zone, the base 11a1 can be omitted, and the valve body 11 can adopt a structure in which the flow path forming bodies 11a2 and 11a3 stand directly from the seat portion 11b.

[0046] To manufacture the sliding contact portion 11a in such a valve body 11, two parallel grooves 11a5 and 11a6 can be machined on a cylindrical base material using a milling cutter, thereby conveniently forming the H-shaped flow path forming bodies 11a2 and 11a3 and the reinforcing portion 11a4 when viewed from the axial direction. Furthermore, when the tool is moved axially from the front end of the base material and the grooves 11a5 and 11a6 are cut on the side of the base material, curved surfaces at the base of the flow path forming bodies 11a2 and 11a3 are formed. When the tool is moved radially closer to the base material to machine the grooves 11a5 and 11a6, as shown... Figure 4 In the valve body 11 of the first modified example of the valve V1 shown in the embodiment, the wall thickness of the reinforcing portion 11a4 is increased relative to the root of the flow path forming bodies 11a2 and 11a3, and the side surface of the reinforcing portion 11a4 is a curved surface. On the other hand, the inner side surfaces of the flow path forming bodies 11a2 and 11a3 are planar along their entire length. Even so, compared to forming the sliding contact portion 11a solely from the flow path forming bodies 11a2 and 11a3 or from the flow path forming bodies 11a2 and 11a3 and the base 11a1, providing the reinforcing portion 11a4 can improve the bending stiffness of the sliding contact portion 11a.

[0047] Valve V consists of a valve body 11 and a spring 12 forming a spring-mass system. The valve body 11 can move axially (i.e., Figure 2 When the valve body 11 moves left and right, and the spring constant of the spring 12 is K, the natural vibration frequency of the spring-mass system in the valve V is (K / M). 1 / 2 / 2π.

[0048] Furthermore, the sliding contact portion 11a has grooves 11a5 and 11a6 for forming a flow path. If the flow path area is increased, the sliding contact portion 11a will exhibit elastic characteristics. Therefore, when the valve V is open and the sliding contact portion 11a is partially inserted into the port 10c of the valve seat component 10, in addition to the axial vibration of the valve body 11, the portion of the sliding contact portion 11a protruding from the port 10c into the valve hole 10d will also exhibit elastic characteristics, thereby inducing a resonant mode of radial vibration in the seat portion 11b and guide portion 11c of the valve body 11. As described above, when the sliding contact portion 11a is considered as a spring, the natural vibration frequency of the valve body 11 is expressed as (k / m) based on the bending stiffness k of the sliding contact portion 11a, the mass m of the seat portion 11b and guide portion 11c of the valve body 11. 1 / 2 / 2π. In the valve V of this embodiment, the natural vibration frequency of the sliding contact portion 11a is set to be higher than the natural vibration frequency of the spring-mass system, that is, set to ensure (k / m). 1 / 2 >(K / M) 1 / 2 Established.

[0049] The structures of valve V and buffer D are as described above. The operation of valve V and buffer D will be explained below. First, the operation of buffer D during extension will be explained. When buffer D extends, piston 3 moves relative to cylinder 1... Figure 1 As the left side moves, the elongation chamber R1 is compressed while the compression chamber R2 is expanded.

[0050] The fluid in the compressed elongation chamber R1 pushes open the elongation damping valve 7 and moves to the compression chamber R2 through the elongation damping valve 7. When the buffer D extends, because the piston rod 2 retracts from the cylinder 1, a hydraulic oil shortage equivalent to the volume of the piston rod 2 retracting from the cylinder 1 is generated in the compression chamber R2. This insufficient hydraulic oil is supplied to the compression chamber R2 from the reservoir T through the suction check valve 9 and the suction passage 10f.

[0051] Therefore, the pressure in the compression chamber R2 is approximately equal to the pressure in the reservoir T. On the other hand, the pressure in the extension chamber R1 is higher than the pressure in the compression chamber R2 due to the extension-side damping valve 7. This is because of the piston 3... Figure 1 While the high pressure of the elongated side chamber R1 acts on the left end face of the piston 3, Figure 1 The pressure of the reservoir acts on the right end face, therefore the buffer D generates a force to prevent the piston 3 from moving relative to the cylinder 1. Figure 1 The damping force that moves to the left is the damping force used to prevent the buffer D from extending.

[0052] Furthermore, when the buffer D retracts, the piston 3 moves within the cylinder 1... Figure 1As the pressure chamber moves to the right, the compression chamber R2 is compressed while the extension chamber R1 expands. The liquid in the compressed chamber R2 moves to the extension chamber R1 via the check valve 8, making the pressure in the extension chamber R1 approximately equal to the pressure in the compression chamber R2. When the buffer D contracts, the piston rod 2 enters the cylinder 1, resulting in excess liquid in the cylinder 1. The volume of this excess liquid is roughly equal to the volume of the piston rod 2 entering the cylinder 1. When the piston rod 2 enters the cylinder 1 and causes the pressure inside the cylinder 1 to reach the opening pressure of valve V, valve V opens, connecting the compression chamber R2 to the reservoir T via the compression-side damping channel P.

[0053] Therefore, when the buffer D retracts, the pressure in both the extension chamber R1 and the compression chamber R2 increases because valve V resists the flow of liquid from cylinder 1 to the reservoir T. As mentioned earlier, when the buffer D retracts, the pressures in the extension chamber R1 and the compression chamber R2 are approximately equal. However, because the right end face of piston 3 (bearing the pressure of compression chamber R2) is larger than the left end face (bearing the pressure of extension chamber R1), and its cross-sectional area is comparable to that of piston rod 2, the buffer D generates a force that hinders the flow of liquid from piston 3 to cylinder 1. Figure 1 The damping force that moves to the right is the damping force that inhibits the contraction action.

[0054] In the valve V of this embodiment, since the ratio of the flow path width to the radial width of the sliding contact portion 11a is set to 1 / 3 or more, a large flow path area can be ensured to reduce pressure overshoot caused by flow rate during valve opening. Figure 5 As shown, the damping force characteristics of the buffer D during the contraction action are as follows: when the valve V is opened, even if the buffer speed in the contraction direction of the buffer increases, resulting in an increase in flow rate, the pressure overshoot remains at a low level, which can reduce the upward gradient of the damping force as the buffer speed increases.

[0055] Furthermore, when valve V is opened, the sliding contact portion 11a is moved from the port 10c of valve seat component 10 into the valve hole 10d, and a portion of the sliding contact portion 11a is inserted into the port 10c. Therefore, the seat portion 11b and guide portion 11c of valve body 11 are elastically supported by the sliding contact portion 11a. Although lateral vibration is likely to occur, since the natural vibration frequency of valve body 11 when the sliding contact portion 11a is regarded as a spring is higher than the natural vibration frequency of the spring mass system formed by valve body 11 and spring 12, even if valve body 11 vibrates axially, it will not excite radial vibration of valve body 11, thereby effectively suppressing the vibration of valve body 11 itself.

[0056] Furthermore, the inner diameter of the clearance hole 2d opening from the front end of the piston rod 2 is larger than the outer diameter of the sliding contact portion 11a of the valve body 11, and the axial length of the clearance hole 2d is greater than the protrusion length of the sliding contact portion 11a from the port 10c to the compression side chamber R2 when the valve body 11 is seated on the annular valve seat 10e. The clearance hole 2d opens at a position that is axially aligned and concentric with the piston rod 2 and the port 10c. Therefore, even when the buffer D reaches its maximum contraction state, the piston rod 2 is closest to the valve seat component 10, and the front end of the sliding contact portion 11a of the valve body 11 (i.e., Figure 2 When the left end of the piston rod 2 protrudes from the port 10c to the compression chamber R2, the sliding contact part 11a is only inserted into the clearance hole 2d, and there is no contact between the piston rod 2 and the valve body 11.

[0057] To ensure that the piston rod 2 does not interfere with the protrusion 10b of the valve seat component 10 when the buffer D reaches its maximum contraction state, the valve seat component 10 in valve V can be thinned from the annular valve seat 10e to the front end of the protrusion 10b (i.e., Figure 1 The wall thickness of the left end of the valve body 11 is reduced, but this reduction in wall thickness will shorten the port 10c. If the axial length of the sliding contact portion 11a of the valve body 11 is correspondingly shortened due to the shortening of the overall length of the port 10c, the amount of retraction required for the valve body 11 to retract from the valve seat component 10 to completely disengage the sliding contact portion 11a from the port 10c will be reduced, making it easier for the sliding contact portion 11a to disengage from the port 10c. In the valve V of this embodiment, the axial movement of the valve body 11 relative to the valve seat component 10 is guided by the sliding contact portion 11a sliding contacting the port 10c. Therefore, if the valve body 11 retracts from the annular valve seat 10e, causing the sliding contact portion 11a to disengage from the port 10c, the valve body 11 will yaw radially. At this time, even if it re-sits on the annular valve seat 10e, the valve V will not be able to close because the sliding contact portion 11a cannot be inserted into the port 10c. However, if the valve body 11 is aligned with the valve seat component 10 by sliding contact between the outer periphery of the seat portion 11b and the inner periphery of the valve hole 10d, the valve seat component 10 needs to be additionally machined. If the alignment of the valve body 11 with the valve seat component 10 is achieved by the guide portion 11c and the spring bracket 13, the sliding contact portion 11a will be difficult to insert into the port 10c due to dimensional errors, which may increase the frictional resistance between the sliding contact portion 11a and the port 10c. Therefore, extremely high machining accuracy is required, which leads to increased costs.

[0058] For the reasons described above, in the valve V of this embodiment, it is ensured that even when the valve seat component 10 is thinned from the annular valve seat 10e to the front end of the protrusion 10b (i.e., Figure 1Even with a wall thickness at the left end, the sliding contact 11a still has a sufficient full length to prevent it from coming out of the port 10c. Furthermore, by providing a clearance hole 2d at the front end of the piston rod 2, even if the buffer D reaches its maximum retracted state, the sliding contact 11a will only be inserted into the clearance hole 2d and will not contact the piston rod 2 or the valve body 11.

[0059] Therefore, in the buffer D of this embodiment, even if the wall thickness of the valve seat component 10 of the valve V from the annular valve seat 10e to the left end of the protrusion 10b is reduced, it is still possible to prevent the piston rod 2 from contacting the sliding contact portion 11a of the valve body 11, thereby limiting the movement of the piston rod 2 toward the retraction side when the buffer D retracts towards the cylinder 1. Figure 1 The right side is widened to ensure the stroke length of the buffer D, while also preventing the sliding contact 11a from dislodging from the port 10c when the valve body 11 retracts from the annular valve seat 10e.

[0060] In summary, the valve V of this embodiment includes: a valve seat component 10 having a port 10c and an annular valve seat 10e disposed around the outlet end of the port 10c; a valve body 11 that can move closer to or further away from the annular valve seat 10e and sit on the annular valve seat 10e; and a spring 12 that applies a force toward the annular valve seat 10e to the valve body 11; wherein the valve body 11 has: a sliding contact portion 11a that is slidably inserted into the inner circumference of the port 10c; and a circular plate-shaped seat portion 11b that is connected to the rear end of the sliding contact portion 11a and sits on the annular valve seat 10e; the natural vibration frequency of the valve body 11 when the sliding contact portion 11a is regarded as a spring is higher than the natural vibration frequency of the spring-mass system composed of the valve body 11 and the spring 12.

[0061] In the valve V constructed in this way, since the natural vibration frequency of the valve body 11 when the sliding contact part 11a is regarded as a spring is higher than the natural vibration frequency of the spring mass system composed of the valve body 11 and the spring 12, when the valve V is opened, even if the valve body 11 generates axial vibration, it will not induce radial vibration, thereby effectively suppressing the vibration of the valve body 11 itself. This prevents noise generation and ensures the generation of stable damping force.

[0062] Furthermore, in the valve V of this embodiment, the sliding contact portion 11a includes: a pair of flow path forming bodies 11a2, 11a3, which stand upright from the seat portion 11b and face each other, while slidingly contacting the inner periphery of the port 10c and forming a flow path between them; and a reinforcing portion 11a4, which is provided between the flow path forming bodies 11a2, 11a3, wherein the ratio of the width of the flow path to the radial width of the sliding contact portion 11a is 1 / 3 or more.

[0063] The valve V constructed in this manner sets the ratio of the flow path width to the radial width of the sliding contact portion 11a to be more than 1 / 3. This ensures a large flow path area to reduce pressure overshoot caused by flow during valve opening. Furthermore, by utilizing the reinforcing portion 11a4 located between the flow path forming bodies 11a2 and 11a3, the flow path forming bodies 11a2 and 11a3 are integrated rather than independently configured. This enhances the bending stiffness of the sliding contact portion 11a and suppresses radial vibration of the valve body 11. Therefore, the valve V constructed in this way prevents noise generation, generates stable and controllable damping force, and achieves excellent pressure relief characteristics with low pressure overshoot.

[0064] Furthermore, the buffer D of this embodiment includes: a cylinder 1, a piston rod 2 that is axially movable and inserted into the cylinder 1, a piston 3 that is annular and movably inserted into the cylinder 1 and connected to the outer periphery of the piston rod 2, and a valve V. The valve seat component 10 closes the end of the cylinder 1 and is axially opposite to the front end of the piston rod 2. The piston rod 2 has a clearance hole 2d that is axially opposite to the port 10c and allows the sliding contact portion 11a of the valve body 11 to be inserted.

[0065] The buffer D constructed in this way ensures that, even with a reduced wall thickness of the valve seat component 10 of the valve V from the annular valve seat 10e to the left end of the protrusion 10b, the sliding contact 11a still has its full length and does not detach from the port 10c. Simultaneously, it prevents the piston rod 2 from contacting the sliding contact 11a of the valve body 11. Therefore, when the buffer D retracts, the limit of movement towards the retracted side of the piston rod 2 is reached by the cylinder 1. Figure 1 The expansion to the right ensures the stroke length of the buffer D.

[0066] In addition, such as Figure 6 The second variation of the valve V2 shown in the embodiment may have a hole 11a7 opening from the front end of the reinforcing part 11a4, a hole 11c1 opening from the rear end of the guide part 11c, and a throttling orifice 11d connecting the hole 11a7 and the hole 11c1 on the valve body 11. With this design, when the buffer D retracts, before the valve V2 opens, liquid flows from the compression chamber R2 through the throttling orifice 11d to the storage tank T, thus... Figure 5 As shown by the dashed line, when the buffer D contracts at low speed, a damping force is generated through the throttling orifice 11d. However, when it contracts at high speed, valve V2 opens, thus... Figure 5 The solid line shows the damping force generated through valve V2.

[0067] And, as Figure 7The valve V3 of the third variation of one embodiment shown can have arc-shaped recesses 11a8 and 11a9 provided on the inner sides of a pair of flow path forming bodies 11a2 and 11a3 opposite to the sliding contact portion 11a, and a cylindrical reinforcing part 11a10 fitted into the recesses 11a8 and 11a9. The valve V3 constructed in this way, by providing the reinforcing part 11a10 between the flow path forming bodies 11a2 and 11a3, makes the flow path forming bodies 11a2 and 11a3 form an integral structure rather than being independently provided, thereby improving the bending stiffness of the sliding contact portion 11a and effectively suppressing radial vibration of the valve body 11. Therefore, the valve V3 constructed in this way can prevent noise generation, generate stable damping force, and simultaneously achieve excellent pressure relief characteristics with low pressure overshoot.

[0068] In addition, such as Figure 8 As shown, in the fourth modified example of valve V4 according to one embodiment, the sliding contact portion 11a can be a cylindrical structure with four or more grooves 11a11, 11a12, 11a13, 11a14 extending from the front end to the rear end for forming a flow path on its outer periphery. In this case, by distributing three or more grooves 11a11, 11a12, 11a13, 11a14 circumferentially on the outer periphery of the sliding contact portion 11a, the central portion of the sliding contact portion 11a can be made solid while ensuring the flow path area, thereby improving the bending stiffness. As described above, in the fourth modified example of valve V4 according to one embodiment, the sliding contact portion 11a is cylindrical with three or more grooves 11a11, 11a12, 11a13, 11a14 extending from the front end to the rear end for forming a flow path on its outer periphery. Therefore, noise generation can be prevented, a stable damping force can be generated, and excellent pressure relief characteristics with low pressure overshoot can be achieved.

[0069] In addition, such as Figure 9 As shown, in the fifth modified example of valve V5 according to one embodiment, the sliding contact portion 11a can be configured as a shape with opposite sides. In this case, by setting the outer periphery shape of the sliding contact portion 11a as a shape with opposite sides, the width of the sliding contact portion 11a can be ensured while maintaining the flow path area and improving the bending stiffness. Therefore, according to the fifth modified example of valve V5 according to one embodiment, noise generation can be prevented, a stable damping force can be generated, and excellent pressure relief characteristics with low pressure overshoot can be achieved.

[0070] Furthermore, valves V, V1, V2, V3, V4, and V5 can be used not only in the aforementioned buffer D, but also in devices constructed in other ways. Moreover, valves V, V1, V2, V3, V4, and V5 can not only serve as the basic valve component in the buffer D, but also have their pistons installed as valve seats on the piston section, and their positions can be arbitrarily changed according to the structure of the buffer.

[0071] The preferred embodiments of the present invention have been described in detail above, but modifications, variations and alterations are possible without departing from the scope of the claims. Symbol Explanation

[0072] 10 Valve seat components 10c port 10e annular valve seat 11 Valve body 11a Sliding contact part 11a2, 11a3 flow path forming body 11a4, 11a10 - Reinforced Section Grooves 11a11, 11a12, 11a13, 11a14 12 springs Valves V, V1, V2, V3, V4, V5

Claims

1. A valve comprising: A valve seat component having a port and an annular valve seat disposed around the outlet end of the port; The valve body can be close to or far from the annular valve seat, and can be seated on the annular valve seat; A spring that exerts a force on the valve body toward the annular valve seat; in, The valve body has a sliding contact portion that can be slidably inserted into the inner periphery of the port, and a circular plate-shaped seat portion connected to the rear end of the sliding contact portion and seated on the annular valve seat. When the sliding contact portion is considered as a spring, the natural vibration frequency of the valve body is higher than the natural vibration frequency of the spring-mass system composed of the valve body and the spring.

2. The valve according to claim 1, wherein, The sliding contact portion has: A pair of flow path forming bodies, which stand upright from the seat and face each other, and slide in contact with the inner periphery of the port, forming a flow path between them; A reinforcing section is disposed 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 more than 1 / 3.

3. The valve according to claim 1, wherein, The sliding contact portion It is cylindrical in shape and has more than three grooves on its outer periphery that extend from the front end to the rear end and form a flow path.

4. A buffer comprising: cylinder; A piston rod that is axially movable and insertable into the cylinder; A piston, in an annular shape, is movably inserted into the cylinder and connected to the outer periphery of the piston rod; The valve according to any one of claims 1 to 3; The valve seat component closes the end of the cylinder and is axially opposite to the front end of the piston rod. The piston rod is provided with a clearance hole that is axially aligned with the port and allows the sliding contact portion of the valve body to be inserted.

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