Shock absorber

Abstract

This damper D is provided with: a cylinder 1; the rod piece 2 is inserted into the air cylinder 1; a piston (3) that divides the inside of the cylinder (1) into an extension-side chamber (R1) and a compression-side chamber (R2); the outer cylinder 4 forms the liquid storage tank T; an annular rod guide (10) for supporting the rod (2) inserted through the cylinder (1), the rod guide (10) having a cylinder fitting section (10d), an annular end section (10d1) facing the extension-side chamber (R1), and an outer cylinder fitting section (10a) fitted to the inner periphery of one end of the outer cylinder (4); and a check valve EC that is provided with a plurality of ports 10f that open at the annular end 10d1 and communicate with the liquid storage tank T, a valve body 13a that is annular and is capable of moving close to or away from the annular end 10d1 in the axial direction so as to open or close the respective ports 10f, and a spring 13c that biases the valve body 13a toward the annular end 10d1, and that permits only the flow of liquid from the liquid storage tank T to the extension-side chamber R1.

Description

Technical Field

[0001] The present invention relates to a shock absorber. Technical Background

[0002] In the past, such shock absorbers have been used for a setting object to suppress vibration of the setting object. For example, it is well known that a shock absorber is used between a car body and a bogie of a railway vehicle to suppress vibration in the left - right direction with respect to the traveling direction of the car body.

[0003] As shown in Japanese Patent JPH11 - 344068A, such a shock absorber includes: a cylinder; an outer cylinder that covers the cylinder and forms a liquid reservoir between the cylinder; a piston that is slidably inserted into the cylinder and divides the inside of the cylinder into a rod - side chamber and a piston - side chamber; a rod that is inserted into the cylinder and connected to the piston; a rod guide that closes one end of the cylinder and one end of the outer tube, and through which the rod is inserted through its inner circumference; a valve housing that closes the other end of the cylinder; a bottom cover that closes the other end of the outer tube; an extension - side damping valve that is provided on the piston and applies resistance to the flow of hydraulic oil flowing from the extension - side chamber to the compression - side chamber; a compression - side damping valve that is provided on the valve housing and applies resistance to the flow of hydraulic oil flowing from the compression - side chamber to the liquid reservoir; an extension - side check valve that is provided on the rod guide and allows only the hydraulic oil to flow from the liquid reservoir to the extension - side chamber; a compression - side check valve that is provided on the valve housing and allows only the hydraulic oil to flow from the liquid reservoir to the compression - side chamber (for example, refer to Patent Document 1). And, the extension - side check valve provided on the rod guide is housed in a valve hole that opens on the outer circumference of the annular rod guide and extends radially, and communicates with the middle of a passage leading from the liquid reservoir provided in the rod guide to the extension - side chamber. Summary of the Invention

[0004] Problems to be Solved by the Invention

[0005] In a conventional shock absorber, when contracting, when the hydraulic oil flows from the compression - side chamber to the liquid reservoir through the damping valve, resistance is applied to the flow of the hydraulic oil by the damping valve, generating a damping force that hinders the contraction operation, the extension - side check valve opens, the extension - side chamber expands due to the movement of the piston, and hydraulic oil is supplied from the liquid reservoir to the extension - side chamber.

[0006] In such a conventional shock absorber, during contraction, since hydraulic oil is supplied to the extension side chamber through the extension side check valve provided on the rod guide, a large flow rate of hydraulic oil flows through the extension side check valve when the shock absorber contracts at high speed. However, since the extension side check valve is provided on the rod guide through which the rod is inserted internally, if the difference between the inner and outer diameters of the rod guide is increased, the diameter of the rod decreases, resulting in insufficient strength, or the diameter of the outer cylinder increases, resulting in a decrease in the mounting performance of the shock absorber in railway vehicles or the like. Therefore, there is a limit to increasing the difference between the inner and outer diameters of the rod guide, and it is difficult to implement an extension side check valve that allows a large flow rate to pass through with the structure of a conventional check valve.

[0007] Therefore, in a conventional shock absorber, it is difficult to increase the flow rate of the extension side check valve. When the shock absorber contracts at high speed, the extension side check valve acts as a resistance, making it difficult to supply hydraulic oil from the reservoir to the extension side chamber. The pressure in the extension side chamber is reduced below atmospheric pressure, which may cause bubbles to form in the hydraulic oil, preventing the generation of a stable damping force, or causing external gas to be sucked into the cylinder.

[0008] Therefore, an object of the present invention is to provide a shock absorber that can generate a stable damping force even during high-speed contraction.

[0009] [Means for Solving the Problem]

[0010] To achieve the above object, the shock absorber of the present invention includes: a cylinder; a rod that is axially movably inserted into the cylinder; a piston that is movably inserted into the cylinder, connected to the rod, and divides the inside of the cylinder into an extension side chamber and a compression side chamber; an outer cylinder that covers the cylinder and forms a reservoir for storing liquid on the outer periphery of the cylinder; an annular rod guide for supporting the rod, which has a cylinder fitting portion fitted to the inner periphery of one end of the cylinder, an annular end portion facing the extension side chamber of the cylinder fitting portion, that is, surrounding the periphery of the rod, and an outer cylinder fitting portion fitted to the inner periphery of one end of the outer cylinder; and a check valve that only allows liquid to flow from the reservoir to the extension side chamber. The check valve includes: a plurality of ports that open side by side in the circumferential direction at one end and are respectively connected to the reservoir; an annular valve body that can approach or move away from the annular end portion in the axial direction to open or close each port; and a spring that applies a force to the valve body toward the annular end portion.

[0011] In the shock absorber configured as such, the check valve has a plurality of ports that are circumferentially arranged side by side and open on an annular end portion around the rod member of the rod guide. Since the open ends of the ports are opened or closed by an annular valve body that approaches or separates from the annular end portion, a plurality of ports are efficiently arranged on a small rod guide to ensure that all ports have a large total flow path area. Even if the liquid flow rate from the liquid reservoir to the extension side chamber is large, the liquid can be allowed to flow from the liquid reservoir to the extension side chamber without imposing too much resistance on it. In addition, the valve body is arranged in the extension side chamber instead of in the rod guide, and all ports can be opened or closed by one valve body, so it will not cause an increase in the size of the rod guide, a decrease in the outer diameter of the rod member, or an increase in the inner diameter of the outer cylinder. [BRIEF DESCRIPTION OF THE DRAWINGS]

[0012] Figure 1 FIG. is a cross-sectional view of a shock absorber having a check valve in one embodiment cut along the axis vertically.

[0013] Figure 2 FIG. is a perspective view of the first cylinder and the second cylinder of the shock absorber in one embodiment.

[0014] Figure 3 FIG. is a cross-sectional view of a shock absorber having a check valve in one embodiment cut along the axis horizontally.

[0015] Figure 4 FIG. is an enlarged cross-sectional view of the check valve in one embodiment.

[0016] Figure 5 FIG. is a view of the rod guide and the collar of the check valve in one embodiment observed from the axial direction.

[0017] Figure 6 FIG. is a longitudinal cross-sectional view of a modified example of the rod guide and the collar. [DETAILED DESCRIPTION OF THE INVENTION]

[0018] The present invention will be described below based on the embodiments shown in the drawings. As Figure 1As shown, the shock absorber D in this embodiment includes: a cylinder 1; a rod 2 inserted into the cylinder 1 movably in the axial direction; a piston 3 inserted into the cylinder 1 movably and connected to the rod 2, dividing the inside of the cylinder 1 into an extension side chamber R1 and a compression side chamber R2; an outer tube 4 covering the cylinder 1 and forming a reservoir T for storing liquid on the outer periphery of the cylinder 1; an extension side damping valve EV that applies resistance to the flow of liquid from the extension side chamber R1 to the reservoir T; a compression side damping valve CV that applies resistance to the flow of liquid from the compression side chamber R2 to the reservoir T; a compression side suction passage CS that allows only the flow of liquid from the reservoir T to the compression side chamber R2; and an extension side check valve EC. Although not shown in detail, the shock absorber D in this embodiment is interposed between the body and the bogie of a railway vehicle, and the damping force generated during extension and contraction suppresses the horizontal lateral vibration relative to the traveling direction of the body. Furthermore, the shock absorber D can be used in installation objects other than railway vehicles.

[0019] In the description of the shock absorber D of the present invention, Figure 1 The up and down direction is taken as the up and down direction of the shock absorber D. Figure 1 The left and right directions in the figure are taken as the left and right directions of the shock absorber D. Figure 1 The direction running through the paper is regarded as the lateral direction of the shock absorber D.

[0020] The following is a detailed description of each part. Figure 1 As shown, the cylinder 1 is cylindrical and has: Figure 1 The annular head side flange 1a protrudes radially outward from the outer periphery of the left end of the middle Figure 1 The annular bottom flange 1b protrudes radially outward from the outer circumference of the middle right end, the annular convex portion 1c protrudes radially outward from the outer circumference between the head flange 1a and the bottom flange 1b, the elongation side concave portion 1d formed by the annular concave portion between the head flange 1a and the convex portion 1c, the compression side concave portion 1e formed by the annular concave portion between the bottom flange 1b and the convex portion 1c, the through hole 1f provided near the head flange 1a and communicating the inside of the cylinder 1 with the elongation side concave portion 1d, the through hole 1g provided near the bottom flange 1b and communicating the inside of the cylinder 1 with the compression side concave portion 1e, and two annular grooves 1h and 1i formed on the outer circumference of the convex portion 1c in the circumferential direction. For example, the cylinder 1 is made by using a thick-walled pipe as a base material, and forming the elongation side concave portion 1d, the compression side concave portion 1e, and the annular grooves 1h and 1i on the outer circumference of the pipe by cutting, grinding, etc. By forming the extension side recess 1d, the compression side recess 1e and the annular grooves 1h and 1i on the outer periphery of the pipe material in this way, the head side flange 1a, the bottom side flange 1b and the convex portion 1c can be formed on the outer periphery of the cylinder 1.

[0021] Seal rings 20 and 21 are housed in annular grooves 1h and 1i formed in the convex portion 1c of the cylinder 1, respectively.Figure 1 The right end of the middle cylinder 1 is closed by a valve housing 9 fitted on the inner periphery of the right end. In addition, Figure 1 A ring-shaped rod guide 10 is fitted on the left end of the middle cylinder 1.

[0022] As Figure 1 and Figure 3 shown, a first cylinder 5 and a second cylinder 6 are fitted on the outer periphery of the cylinder 1. The inner periphery of the first cylinder 5 is fitted on the outer peripheries of the head-side flange 1a and the convex portion 1c of the cylinder 1. Figure 1 The right end of the first cylinder 5 is arranged at the axial center of the convex portion 1c of the cylinder 1, Figure 1 The left end of the first cylinder 5 is arranged to the left of the left end of the Figure 1 cylinder 1. The inner periphery of the first cylinder 5 faces the outer periphery of the head-side flange 1a of the cylinder 1 and faces the sealing ring 20 accommodated in the annular groove 1h of the convex portion 1c, and covers the entire elongation-side recess 1d on the outer periphery of the cylinder 1. Therefore, when the cylinder 1 is fitted in the first cylinder 5, an elongation-side channel EP formed by the elongation-side recess 1d is formed between the first cylinder 5 and the cylinder 1. The elongation-side channel EP communicates with the elongation-side chamber R1 in the cylinder 1 through a through hole 1f provided in the cylinder 1.

[0023] Furthermore, as Figure 2 and Figure 3 shown, the first cylinder 5 is provided with a ring-shaped first boss portion 5a welded to its outer periphery. The inside of the first boss portion 5a communicates with the inner peripheral side of the first cylinder 5 through a hole 5c penetrating the cylinder wall of the first cylinder 5, and the first boss portion 5a and the hole 5c form a continuous hole penetrating the first cylinder 5 in the radial direction. Therefore, the inside of the first boss portion 5a communicates with the elongation-side channel EP between the first cylinder 5 and the cylinder 1. And, the inner diameter of the first boss portion 5a is larger than the inner diameter of the hole 5c, and there is a step in the middle of the continuous hole composed of the first boss portion 5a and the hole 5c. In addition, Figure 1 On the outer periphery of the right end of the first cylinder 5, a flat surface 5b as Figure 2 shown is provided on a part in the circumferential direction. In the shock absorber D of the present embodiment, the first cylinder 5 is provided on the outer peripheral side of such a cylinder 1, and the elongation-side channel EP is provided between the cylinder 1 and the first cylinder 5. In the case where the first cylinder 5 is not provided, a first boss portion needs to be provided at a position opposite to the through hole 1f outside the working range of the piston 3 provided in the cylinder 1. Therefore, although the setting position of the first boss portion is restricted, by providing the first cylinder 5, the first boss portion 5a can be provided within the range of the first cylinder 5 without being restricted by the position of the through hole 1f, and the degree of freedom of the setting position of the first boss portion 5a is improved.

[0024] In addition, the second cylinder 6 has an outer diameter equal to the outer diameter of the first cylinder 5, and its inner periphery can be fitted on the outer peripheries of the bottom-side flange 1b and the convex portion 1c of the cylinder 1. Figure 1The left end of the second cylinder 6 is disposed at the axial center of the convex portion 1c of the cylinder 1. Figure 1 The right end of the second cylinder 6 is disposed beyond Figure 1 the right side of the right end of the cylinder 1. The inner circumference of the second cylinder 6 faces the outer circumference of the bottom flange 1b of the cylinder 1, faces the sealing ring 21 accommodated in the annular groove 1i of the convex portion 1c, and covers the entire compression-side recess 1e on the outer circumference of the cylinder 1. Therefore, when the cylinder 1 is fitted into the second cylinder 6, a compression-side passage CP formed by the compression-side recess 1e is formed between the second cylinder 6 and the cylinder 1. The compression-side passage CP communicates with the inside of the compression-side chamber R2 in the cylinder 1 through the through hole 1g provided in the cylinder 1. Thus, when the cylinder 1 is inserted into the inner circumferences of the first cylinder 5 and the second cylinder 6, the elongation-side recess 1d provided on the outer circumference of the cylinder 1 and forming an elongation-side passage EP between the first cylinder 5, the compression-side recess 1e provided on the outer circumference of the cylinder 1 and forming a compression-side passage CP between the second cylinder 6, and the convex portion 1c of the cylinder 1 separate the elongation-side recess 1d and the compression-side recess 1e. And, in the present embodiment, two annular grooves 1h, 1i are provided on the outer circumference of one convex portion 1c, the sealing ring 20 in close contact with the first cylinder 5 is accommodated in the annular groove 1h, and the sealing ring 21 in close contact with the second cylinder 6 is accommodated in the annular groove 1i. This sealing ring seals between the elongation-side passage EP and the compression-side passage CP. It is also possible to provide one annular groove with respect to the convex portion 1c, and accommodate one sealing ring that is in close contact with both the inner circumferences of the first cylinder 5 and the second cylinder 6 and seals between the elongation-side passage EP and the compression-side passage CP. In this way, the elongation-side passage EP and the compression-side passage CP are separated by the convex portion 1c, but since the elongation-side passage EP and the compression-side passage CP are sealed by the sealing rings 20, 21, the outer circumference of the convex portion 1c may not contact the inner circumferences of the first cylinder 5 and the second cylinder 6.

[0025] Furthermore, as Figure 2 and Figure 3 shown, the second cylinder 6 includes an annular second boss portion 6a mounted on its outer circumference by welding. The inside of the second boss portion 6a communicates with the inner circumferential side of the second cylinder 6 through a hole 6c penetrating the wall of the second cylinder 6. The second boss portion 6a and the hole 6c form a continuous hole penetrating the second cylinder 6 in the radial direction. Therefore, the inside of the second boss portion 6a communicates with the compression-side passage CP between the second cylinder 6 and the cylinder 1. And, the inner diameter of the second boss portion 6a is larger than the inner diameter of the hole 6c, and there is a step in the middle of the continuous hole formed by the second boss portion 6a and the hole 6c. In addition, Figure 1 on the outer circumference of the right end of the second cylinder 6, as Figure 2As shown, a flat surface 6b is provided on a part of the circumferential direction. In the shock absorber D of the present embodiment, a second cylinder 6 is provided on the outer peripheral side of such a cylinder 1, and a compression side passage CP is provided between the cylinder 1 and the second cylinder 6. In the case where the second cylinder 6 is not provided, since a second boss portion needs to be provided at a position opposite to the through hole 1g outside the working range of the piston 3 provided on the cylinder 1, the setting position of the second boss portion is restricted. However, by providing the second cylinder 6, the second boss portion 6a can be provided within the range of the second cylinder 6 without being restricted by the position of the through hole 1g, and the degree of freedom of the setting position of the second boss portion 6a is improved.

[0026] When the first cylinder 5 and the second cylinder 6 configured in this way are fitted to the outer periphery of the cylinder 1, the opposing end portions 5d, 6d are butted and abutted against each other. Moreover, when the first cylinder 5 and the second cylinder 6 are rotated and arranged with the flat surfaces 5b, 6b formed on the outer peripheries of the end portions 5d, 6d of the first cylinder 5 and the second cylinder 6 as marks so that the flat surfaces 5b, 6b are in the same position in the circumferential direction, the circumferential relative arrangement of the first boss portion 5a and the second boss portion 6a of the first cylinder 5 and the second cylinder 6 is the same as the design.

[0027] In addition, when the end portions 5d, 6d of the first cylinder 5 and the second cylinder 6 are butted against each other so that the flat surfaces 5b, 6b face each other, the flat surfaces 5b, 6b form a flush surface. Moreover, a permanent magnet 40 is mounted on the flush surface formed by the flat surfaces 5b, 6b. If the first cylinder 5 and the second cylinder 6 are soft magnetic bodies, the permanent magnet 40 can be mounted on the first cylinder 5 and the second cylinder 6 by its own suction force. If the first cylinder 5 and the second cylinder 6 are non-magnetic bodies, the permanent magnet 40 can be adhesively mounted on the first cylinder 5 and the second cylinder 6. In this way, since the marks for circumferential alignment of the first cylinder 5 and the second cylinder 6 can be used as the flat surfaces 5b, 6b, when the first cylinder 5 and the second cylinder 6 are butted for circumferential alignment, a flush surface for setting the permanent magnet 40 is formed by the flat surfaces 5b, 6b. Therefore, the permanent magnet 40 can be easily mounted and the permanent magnet 40 can be prevented from falling off. In addition, if the shock absorber D is placed horizontally, the flat surfaces 5b, 6b are arranged below the liquid storage tank T, and the permanent magnet 40 is also arranged below the liquid storage tank T. Therefore, when assembling the shock absorber D, the permanent magnet 40 is arranged below the liquid storage tank T that accumulates contaminants in the liquid, and thus it is easier to capture contaminants.

[0028] The outer cylinder 4 is disposed on the outer peripheral side of the first cylinder 5 and the second cylinder 6, forming a liquid storage tank T that covers the cylinder 1, the first cylinder 5, and the second cylinder 6 and stores liquid inside. The liquid storage tank T is formed by the annular gap between the outer cylinder 4 and the first cylinder 5 and the second cylinder 6. In addition to the liquid, gas is also filled in the liquid storage tank T. And the liquid, for example, can be hydraulic oil, but can also be a liquid other than hydraulic oil. The gas, for example, can be an inert gas such as nitrogen, but in addition to the inert gas, it can also be air. And the first cylinder 5 and the second cylinder 6 are fitted on the outer periphery of the cylinder 1, and an extension side passage EP and a compression side passage CP are provided between the cylinder 1 and the first cylinder 5 and the second cylinder 6. However, instead of the first cylinder 5 and the second cylinder 6, pipes forming the extension side passage EP and the compression side passage CP can be accommodated in the liquid storage tank T. In this case, the liquid storage tank T can be formed in the annular gap between the cylinder 1 and the outer cylinder 4.

[0029] As Figure 3 shown, the outer cylinder 4 is provided with a first hole 4a that is radially opposed to the first boss portion 5a of the first cylinder 5, and a second hole 4b that is radially opposed to the second boss portion 6a of the second cylinder 6. In addition, a first base 23 and a second base 24 are mounted on the outer periphery of the outer cylinder 4. An extension side damper valve EV is disposed on the radially outer side of the first hole 4a of the outer cylinder 4, and a compression side damper valve CV is disposed on the radially outer side of the second hole 4b. Therefore, the first hole 4a and the second hole 4b are disposed at positions that maintain a sufficient distance in the circumferential direction or the axial direction of the outer cylinder 4, so as to ensure that the extension side damper valve EV and the compression side damper valve CV do not interfere with each other.

[0030] Moreover, the first boss portion 5a of the first cylinder 5 is disposed at a position radially opposed to the first hole 4a of the outer cylinder 4, and the second boss portion 6a of the second cylinder 6 is disposed at a position radially opposed to the second hole 4b of the outer cylinder 4. Therefore, planes 5b, 6b serving as marks of the relative positions of the first cylinder 5 and the second cylinder 6 are provided on the first cylinder 5 and the second cylinder 6, so that the first boss portion 5a and the second boss portion 6a can be opposed to the corresponding first hole 4a and second hole 4b according to the installation positions of the first hole 4a and the second hole 4b of the outer cylinder 4 respectively. Therefore, if the planes 5b, 6b are positioned relative to each other in the circumferential direction to position the relative positions of the first cylinder 5 and the second cylinder 6 in the circumferential direction, and the outer cylinder 4 is disposed at an appropriate position in the circumferential direction relative to the first cylinder 5 and the second cylinder 6, the first boss portion 5a and the second boss portion 6a are respectively opposed to the corresponding first hole 4a and second hole 4b.

[0031] As Figure 3As shown, the first base 23 is a base for mounting the extension side damping valve EV on the shock absorber D. The inner side surface opposite to the outer periphery of the outer cylinder 4 is curved along the outer periphery of the outer cylinder 4 so that the inner side surface abuts against the outer periphery of the outer cylinder 4. The end surface on the side opposite to the outer cylinder is rectangular and is a flat valve mounting surface 23a. In addition, the first base 23 has a hole 23b that passes through the center in the radial direction of the outer cylinder 4 and communicates with the first hole 4a, and screw holes (not shown) provided at the four corners on the side opposite to the outer cylinder. The first base 23 configured in this way is fixed to the outer periphery of the outer cylinder 4 by welding.

[0032] As Figure 3 shown, the second base 24 is a base for mounting the compression side damping valve CV on the shock absorber D. The inner side surface opposite to the outer periphery of the outer cylinder 4 is curved along the outer periphery of the outer cylinder 4 so that the inner side surface abuts against the outer periphery of the outer cylinder 4. The end surface on the side opposite to the outer cylinder is rectangular and is a flat valve mounting surface 24a. In addition, the second base 24 has a hole 24b that passes through the center in the radial direction of the outer cylinder 4 and communicates with the second hole 4b, and screw holes (not shown) provided at the four corners on the side opposite to the outer cylinder. The second base 24 configured in this way is fixed to the outer periphery of the outer cylinder 4 by welding.

[0033] Moreover, a rod guide 10 is fitted on the inner periphery of one end (i.e., Figure 1 the left end in the figure) of the cylinder 1, the first cylinder 5, and the outer cylinder 4. The rod guide 10 is annular, supports the rod 2 inserted through its inner periphery and axially movably inserted into the cylinder 1, and guides the axial movement of the rod 2 relative to the cylinder 1. In addition, Figure 1 a disk-shaped valve housing 9 is fitted on the right ends of the cylinder 1 and the second cylinder 6 in the figure and is closed by the valve housing 9. Moreover, Figure 1 a bottom cover 16 is mounted on the right end of the outer cylinder 4 in the figure and is closed by the bottom cover 16.

[0034] The rod 2 projects outside the cylinder 1 at the left end in Figure 1 the figure and is connected to a piston 3 axially movably inserted into the cylinder 1 at the right end in Figure 1 the figure. In addition, Figure 1 a bracket 2a is provided at the left end of the rod 2 in the figure, and the bracket can be mounted on a mounting portion (not shown) provided on the bogie of a railway vehicle. The rod 2 is axially (i.e., Figure 1 the left-right direction in the figure) movably inserted into the cylinder 1 and can axially displace relative to the cylinder 1 together with the piston 3. In addition, the piston 3 divides the cylinder 1 into an extension side chamber R1 and a compression side chamber R2 filled with liquid, and when moving axially in the cylinder 1 together with the rod 2, it will expand or contract the extension side chamber R1 and the compression side chamber R2.

[0035] The valve housing 9 is disk-shaped and has: a small-diameter portion 9a fitted on the inner periphery of the cylinder 1, where the cylinder 1 is provided inFigure 1 On the upper left end; the large-diameter portion 9b is connected to the small-diameter portion 9a Figure 1 on the upper right and is fitted into the inner circumference of the second cylinder 6; the flange 9c is provided on the outer circumference of the large-diameter portion 9b and abuts against the Figure 1 upper right end of the second cylinder 6; the recess 9d opening from the Figure 1 upper left end of the small-diameter portion 9a; the plurality of ports 9e opening from the Figure 1 upper right end of the large-diameter portion 9b and communicating with the recess 9d. A plurality of ports 9e are arranged on the circumferential circle along the recess 9d.

[0036] In addition, a compression-side check valve 15 is accommodated in the recess 9d of the valve housing 9. The compression-side check valve includes: an annular valve body 15a that can open or close the outlet end of the port 9e, that is, Figure 1 the left end shown; an annular retaining ring 15b installed on the side portion of the opening side of the recess 9d of the valve housing 9; a helical spring 15c clamped between the valve body 15a and the retaining ring 15b, and applying a force to the valve body 15a toward the bottom side of the recess 9d.

[0037] The bottom cover 16 is installed by welding to the Figure 1 right end shown of the outer cylinder 4, closing the Figure 1 right end shown of the outer cylinder 4, and having a recess 16a fitted to the Figure 1 right end shown of the large-diameter portion 9b of the valve housing 9, and a passage 16b connecting the recess 16a to the liquid storage tank T. In addition, Figure 1 a bracket 16c is provided on the right end, and the bracket can be installed on a mounting portion (not shown) provided on the body of a railway vehicle. Therefore, the shock absorber D can be clamped between the bogie and the body of the railway vehicle (not shown) through the bracket 2a of the rod 2 and the bracket 16c of the bottom cover 16.

[0038] The inlet end of the port 9e of the valve housing 9 communicates with the liquid storage tank T through the recess 16a and the passage 16b, and the outlet end of the port 9e communicates with the compression-side chamber R2. Therefore, the compression-side suction passage CS is formed by the port 9e, the recess 16a, and the passage 16b.

[0039] Regarding the flow of the liquid flowing from the liquid storage tank T to the compression-side chamber R2 through the port 9e, the compression-side check valve 15 compresses the helical spring 15c by the valve body 15a so that it moves in the recess 9d toward Figure 1The valve is opened by moving to the left, thereby opening port 9e to allow liquid to flow from liquid storage tank T to compression side chamber R2. Conversely, for the flow of liquid from compression side chamber R2 to liquid storage tank T, compression side check valve 15 pushes valve body 15a towards the bottom of recess 9d by the pressure in compression side chamber R2 and the force of helical spring 15c, closing port 9e to close the valve, thereby preventing the above-mentioned liquid from flowing from compression side chamber R2 to liquid storage tank T. Since compression side check valve 15 opens multiple ports 9e arranged side by side on the same circumference, even if the liquid flow rate from liquid storage tank T to compression side chamber R2 is large, the liquid can flow from liquid storage tank T to compression side chamber R2 without much resistance. Thus, compression side check valve 15 is provided on compression side suction passage CS, and compression side suction passage CS is set as a one-way passage that only allows liquid to flow from liquid storage tank T to compression side chamber R2 and prevents reverse liquid flow.

[0040] Next, as Figure 4 and Figure 5 shown, rod guide 10 is annular and includes: an outer cylinder fitting portion 10a that fits into the inner circumference of outer cylinder 4; a collar fitting portion 10b into which annular collar 14 is fitted, connected to the right side of outer cylinder fitting portion 10a in Figure 4 and having an outer diameter smaller than that of outer cylinder fitting portion 10a; a first cylinder fitting portion 10c fitted on the outer circumference, connected to the right side of collar fitting portion 10b in Figure 4 and having an outer diameter smaller than that of collar fitting portion 10b; a cylinder fitting portion 10d fitted on the outer circumference, connected to the right side of first cylinder fitting portion 10c in Figure 4 and having an outer diameter smaller than that of first cylinder fitting portion 10c; an annular end portion 10d1 surrounding the right end rod 2 in Figure 4 and facing the extension side chamber R1 of cylinder fitting portion 10d; an annular valve mounting portion 10e protruding from the inner circumference of annular end portion 10d1; eight ports 10f opening from the outer circumference of valve mounting portion 10e and communicating with the outer circumference of collar fitting portion 10b; a return passage 10g opening from the right end of outer cylinder fitting portion 10a in Figure 4 and leading to the left end.

[0041] Moreover, for the eight ports 10f, one end faces the extension side chamber R1 of cylinder fitting portion 10d, opens side by side in the circumferential direction on annular end portion 10d1 surrounding the right end rod 2 in Figure 4 and extends radially, while the other end opens at equal intervals at the bottom of annular passage 10b1, which is formed by an annular groove provided on the outer circumference of collar fitting portion 10b along the circumferential direction. Since annular passage 10b1 is provided on the entire outer circumference of collar fitting portion 10b, it communicates with all eight ports 10f. In addition, each port 10f communicates with extension side chamber R1 and liquid storage tank T respectively.

[0042] A cylindrical bushing 11 is installed on the inner circumference of the rod guide 10. It is in sliding contact with the outer circumference of the rod member 2 and guides the axial movement of the rod member 2, thereby ensuring smooth movement of the rod member 2. A sealing ring 12 that closely adheres to the outer circumference of the rod member 2 is also installed.

[0043] Moreover, with respect to the annular end portion 10d1 of the cylinder fitting portion 10d of the rod guide 10, an annular valve seat 10d2 surrounding the outer circumference of each port 10f is provided, and an annular inner circumferential seat portion 10d3 is provided on the inner circumference of each port 10f. An annular window 10d4 is provided between the annular valve seat 10d2 and the inner circumferential seat portion 10d3, which is formed by an annular recess communicating with one end of each port 10f. Thus, the annular end portion 10d1 is the end portion facing the extended side chamber R1 of the cylinder fitting portion 10d, and includes the annular valve seat 10d2, the inner circumferential seat portion 10d3, and the annular window 10d4.

[0044] The valve mounting portion 10e is cylindrical and protrudes axially from the inside of the inner circumferential seat portion 10d3 on the inner circumferential side of each port 10f of the cylinder fitting portion 10d. In addition, the valve mounting portion 10e has a flange 10e1 that protrudes radially outward on the outer circumference of the right end shown in Figure 4 the figure.

[0045] In addition, as shown in Figure 3 and Figure 4 the figure, the collar 14 fitted on the outer circumference of the collar fitting portion 10b of the rod guide 10 is annular, its outer diameter is smaller than the inner diameter of the outer cylinder 4, and it has a cutout 14a provided on a part of the outer circumference, a plurality of collar ports 14b that open from the end face of the cutout 14a and communicate with the inner circumference, and a pin insertion groove 14c provided on the outer circumference at a position opposite to the cutout 14a in the circumferential direction.

[0046] When the collar 14 is press-fitted and fitted on the outer circumference of the collar fitting portion 10b of the rod guide 10, it can be fixed on the outer circumference of the collar fitting portion 10b. Each collar port 14b of the collar 14 faces the annular passage 10b1 respectively, and all of the collar ports 14b and all of the ports 10f communicate with each other through the annular passage 10b1. And in the shock absorber D of the present embodiment, an annular passage 10b1 that communicates the port 10f and the collar port 14b is provided on the outer circumference of the collar fitting portion 10b of the rod guide 10. Instead of providing it on the outer circumference of the collar fitting portion 10b, an annular groove that forms an annular passage communicating the port 10f and the collar port 14b can also be provided on the inner circumference of the collar 14.

[0047] Moreover, when the rod guide 10 with the collar 14 fitted on its outer periphery has its cylinder fitting portion 10d fitted into the cylinder 1, its first cylinder fitting portion 10c fitted into the first cylinder 5, and its outer cylinder fitting portion 10a fitted into the outer cylinder 4, then Figure 1 the left end of the middle cylinder 1 abuts against Figure 1 the right end of the first cylinder fitting portion 10c of the rod guide 10, Figure 1 the left end of the first cylinder 5 abuts against Figure 1 the right end of the collar fitting portion 10b of the rod guide 10. In addition, the outer diameter of the collar fitting portion 10b is smaller than the outer diameter of the first cylinder 5, and the axial lengths of the collar 14 and the collar fitting portion 10b are equal. When the first cylinder fitting portion 10c of the rod guide 10 is fitted into the first cylinder 5, Figure 1 the outer peripheral side of the left end of the first cylinder 5 abuts against the collar 14, and the collar 14 does not fall off from the collar fitting portion 10b.

[0048] In addition, if the rod guide 10 is fitted to the left ends of the cylinder 1, the first cylinder 5, and the outer cylinder 4 as Figure 1 shown, the collar port 14b where the cutout 14a of the collar 14 opens communicates with the liquid storage tank T. Therefore, the inlet end of the port 10f of the rod guide 10 communicates with the liquid storage tank T through the collar port 14b, and the outlet end of the port 10f communicates with the extension side chamber R1 inside the cylinder 1.

[0049] Moreover, the collar port 14b opens at the cutout 14a provided on the outer periphery of the collar 14, such that the cross-sectional area of the gap between the cutout 14a and the outer cylinder 4 is larger than the total cross-sectional area of all the collar ports 14b and the total cross-sectional area of all the ports 10f. By providing the cutout 14a in this way, even if there is not enough gap between the outer peripheral surface of the collar 14 and the inner peripheral surface of the outer cylinder 4, when the liquid passes through the gap between the end face of the cutout 14a and the outer cylinder 4, this gap does not impose excessive resistance on the flow of the liquid. In addition, as Figure 4 shown, by inserting the pin 18 passing through the outer cylinder 4 into the pin insertion groove 14c, the circumferential rotation of the collar 14 relative to the outer cylinder 4 is stopped and it is positioned circumferentially, so that the cutout 14a faces downward of the shock absorber D. Therefore, in the liquid storage tank T of the horizontally mounted shock absorber D, Figure 1 the upper part of the liquid storage tank T is filled with gas, and the cutout 14a forming the inlet end of the collar port 14b always faces downward of the shock absorber D and faces the liquid, so care should be taken to ensure that the inlet end of the collar port 14b does not face the gas. Also, care should be taken that the return passage 10g provided on the rod guide 10 has an opening opposite to the pin insertion groove 14c of the collar 14, so that it is not blocked when the collar 14 is fitted to the collar fitting portion 10b.

[0050] In addition, in the present embodiment, the collar 14 is fitted on the outer periphery of the collar fitting portion 10b of the rod guide 10. By pressing the collar 14 onto the outer periphery of the rod guide 10, the space between the collar 14 and the rod guide 10 is sealed. A sealing member may also be provided between the collar 14 and the rod guide 10 to prevent the port 10f from communicating with the liquid storage tank T without passing through the collar port 14b.

[0051] The check valve EC is configured such that the rod guide 10 serves as a valve seat member, and includes a valve body 13a for opening or closing the port 10f provided on the rod guide 10 and a helical spring 13c which serves as a spring for applying a force to the valve body 13a. The valve body 13a and the helical spring 13c constituting the check valve EC are mounted on the outer periphery of the valve mounting portion 10e of the rod guide 10. More specifically, the valve body 13a is formed of an annular plate which can be disengaged from and seated on the annular valve seat 10d2 and the inner peripheral seat portion 10d3 on the annular end portion 10d1 at the right end shown in the [reference figure], so as to open or close the open end of the port 10f. The valve body 13a makes inner peripheral sliding contact with the outer periphery of the valve mounting portion 10e, and can displace the outer periphery of the valve mounting portion 10e in the axial direction (the left - right direction shown in the [reference figure]), and maintain it without axial jitter. When separated from the right end of the annular valve seat 10d2, each port 10f is opened simultaneously, and when abutted against the right end of the cylinder fitting portion 10d, each port 10f is cut off simultaneously. Figure 1 The conical helical spring 13c serving as a spring is sandwiched between a spring seat 13b which is fitted on the outer periphery of the valve mounting portion 10e and has an L - shaped cross - section in the axial direction relative to the valve body 13a and the valve body 13a, and applies a force to the valve body 13a toward the right end of the cylinder fitting portion 10d. Figure 1 shown in the [reference figure]), and holds it without axial jitter. When separated from the right end of the annular valve seat 10d2 shown in the [reference figure], each port 10f is opened simultaneously, and when abutted against the right end of the cylinder fitting portion 10d shown in the [reference figure], each port 10f is cut off simultaneously. Figure 1 When separated from the right end of the annular valve seat 10d2 in the [reference figure], each port 10f is opened simultaneously, and when abutted against the right end of the cylinder fitting portion 10d in the [reference figure], each port 10f is cut off simultaneously. Figure 1 When separated from the right end of the annular valve seat 10d2 in the [reference figure], each port 10f is opened simultaneously, and when abutted against the right end of the cylinder fitting portion 10d in the [reference figure], each port 10f is cut off simultaneously.

[0052] The conical helical spring 13c serving as a spring is sandwiched between a spring seat 13b which is fitted on the outer periphery of the valve mounting portion 10e and has an L - shaped cross - section in the axial direction relative to the valve body 13a and the valve body 13a, and applies a force to the valve body 13a toward the right end of the cylinder fitting portion 10d.

[0053] Moreover, the spring seat 13b can be prevented from slipping off the valve mounting portion 10e by a snap ring 13d. The snap ring 13d is mounted on the outer periphery of the valve mounting portion 10e by abutting against a flange 10e1 provided on the front end (i.e., the right end in the [reference figure]) of the outer periphery of the valve mounting portion 10e. Figure 1 Moreover, the spring seat 13b can be prevented from slipping off the valve mounting portion 10e by a snap ring 13d. The snap ring 13d is mounted on the outer periphery of the valve mounting portion 10e by abutting against a flange 10e1 provided on the front end (i.e., the right end in the [reference figure]) of the outer periphery of the valve mounting portion 10e.

[0054] The check valve EC configured in this way is provided on the extended - side suction passage ES composed of the port 10f, the annular passage 10b1, and the collar port 14b, and can open or close the port 10f. Moreover, for the flow of the liquid flowing from the liquid storage tank T to the extended - side chamber R1 through the port 10f, the check valve EC compresses the helical spring 13c by the valve body 13a to move the outer periphery of the valve mounting portion 10e of the rod guide 10 toward the front end side (i.e., the right end in the [reference figure] shown in the [reference figure]) Figure 1When moving to the right side (right side in the figure), the valve is opened, so opening port 10f allows the liquid to flow from the liquid storage tank T to the extension side chamber R1. Conversely, for the flow of the liquid flowing from the extension side chamber R1 to the liquid storage tank T, the check valve EC presses the valve body 13a against the cylinder fitting portion 10d by the pressure of the extension side chamber R1 and the acting force of the helical spring 13c Figure 1 right end in the figure, closes port 10f to close the valve, thereby preventing the flow of the liquid from moving from the extension side chamber R1 to the liquid storage tank T. As described above, the check valve EC is provided on the extension side suction passage ES, and the extension side suction passage ES is set as a one-way passage that only allows the liquid to flow from the liquid storage tank T to the compression side chamber R2 and prevents the reverse flow of the liquid.

[0055] The check valve EC has a plurality of ports 10f that are arranged side by side in the circumferential direction on the annular end portion 10d1 around the rod 2 of the rod guide 10. Since the open ends of the ports 10f are opened or closed by the annular valve body 13a that approaches or moves away from the annular end portion 10d1, a plurality of ports 10f can be efficiently arranged on the small rod guide 10, ensuring that all ports 10f have a large total flow path area. Even if the liquid flow rate from the liquid storage tank T to the extension side chamber R1 is large, it allows the liquid to flow from the liquid storage tank T to the extension side chamber R1 without imposing too much resistance. Thus, when setting the extension side suction passage ES that connects the extension side chamber R1 and the liquid storage tank T, since the rod guide 10 that has the rod 2 inserted in the center and is fitted to the cylinder 1 has a plurality of ports 10f arranged around the rod 2 to ensure the flow path area, a large flow rate of liquid can be supplied from the liquid storage tank T to the extension side chamber R1, and there will be no shortage of liquid supply in the extension side chamber R1. Also, the spring of the check valve EC can be a spring other than the helical spring 13c. And the number of ports 10f provided is appropriately set so that in the environment where the shock absorber D is actually used, when the liquid with the predicted maximum flow rate passes through the extension side suction passage ES, the liquid supply in the extension side chamber R1 will not stagnate.

[0056] A collar 14 is fitted on the outer periphery of the rod guide 10 constructed as described above, and after the extension side check valve 13 is installed on the valve mounting portion 10e, it is fitted to the Figure 1 left end shown in the figure of the cylinder 1 that has the first cylinder 5 and the second cylinder 6 fitted on its outer periphery. At this time, between the outer periphery of the first cylinder fitting portion 10c of the rod guide 10 and Figure 1 the inner periphery of the left end of the first cylinder 5 in the figure is fitted. In addition, on the inner periphery of the right end of the cylinder 1 and the second cylinder 6 that have the first cylinder 5 and the second cylinder 6 fitted on their outer peripheries Figure 1 the valve housing 9 with the compression side check valve 15 installed is fitted. The assembled cylinder 1, first cylinder 5, second cylinder 6, valve housing 9, and rod guide 10 are inserted into Figure 1 the outer cylinder 4 with the bottom cover 16 installed on the right end in the figure and then threadedly coupled to theFigure 1 The sealing housing 17 and the bottom cover 16 on the inner circumference of the left middle end are clamped and fixed within the outer cylinder 4. And the sealing housing 17 is annular and has: a threaded portion 17a that is threadedly engaged with a threaded portion 4c formed on the inner circumference of the left middle end of the outer cylinder 4 on its outer circumference; a sealing ring 17b and a dust-proof sealing ring 17c that are accommodated in annular recesses provided on the inner circumference and are in sliding contact with the outer circumference of the rod member 2. Therefore, when the sealing housing 17 is threadedly engaged and tightened with the outer cylinder 4, the cylinder 1, the first cylinder 5, the second cylinder 6, the valve housing 9, and the rod guide 10 are fixed within the outer cylinder 4 by an axial force applied through the sealing housing 17 and the bottom cover 16. As described above, the outer circumference of the rod member 2 is sealed by the sealing ring 17b, and the liquid adhering to the outer circumference of the rod member 2 and passing over the sealing ring 12 mounted on the rod guide 10 is scraped off by the sealing ring 17b and then returns to the liquid storage tank T through the return passage 10g of the rod guide 10. Figure 1 In the middle left end inner circumference, the threaded portion 17a is threadedly engaged with the threaded portion 4c formed on the outer cylinder 4; the sealing ring 17b and the dust-proof sealing ring 17c are accommodated in annular recesses provided on the inner circumference and are in sliding contact with the outer circumference of the rod member 2. Figure 1 In the middle left end and the right end, the annular recesses are in sliding contact with the outer circumference of the rod member 2. Therefore, when the sealing housing 17 is threadedly engaged and tightened with the outer cylinder 4, the cylinder 1, the first cylinder 5, the second cylinder 6, the valve housing 9, and the rod guide 10 are fixed within the outer cylinder 4 by an axial force applied through the sealing housing 17 and the bottom cover 16. As described above, the outer circumference of the rod member 2 is sealed by the sealing ring 17b, and the liquid adhering to the outer circumference of the rod member 2 and passing over the sealing ring 12 mounted on the rod guide 10 is scraped off by the sealing ring 17b and then returns to the liquid storage tank T through the return passage 10g of the rod guide 10.

[0057] And, in the above case, the collar 14 opens the collar port 14b at the notch 14a and sucks the liquid from the liquid storage tank T and supplies it to the extension side chamber R1. However, as Figure 6 shown by the collar 141, a suction pipe 142 can be installed on the collar 141.

[0058] As Figure 6 shown, the collar 141 is annular, the outer diameter is smaller than the inner diameter of the outer cylinder 4, the inner diameter on the liquid storage tank side is small, the inner circumference has a large inner diameter portion 141a and a small inner diameter portion 141b, and also has an internal passage 141c that radially opens from a part of the inner circumference in the circumferential direction of the large inner diameter portion 141a, five jack holes 141d that open from the liquid storage tank side end and communicate with the internal passage 141c, a pin through hole 141e that opens at the end opposite to the liquid storage tank side, and a pin insertion groove 141f provided on the outer circumference and Figure 6 in the upper middle part, which is fitted on the outer circumference of the collar fitting portion 10b of the rod guide 10. At each jack hole 141d of the collar 141, the base end of the suction pipe 142 with the front end disposed near the center of the liquid storage tank T is respectively fitted and installed.

[0059] As Figure 6 shown, the rod guide 10 fitted with the collar 141 matches the inner circumference shape of the collar 141. The collar fitting portion 10b has a large diameter portion 10b2 that fits with the large inner diameter portion 141a of the collar 141 and a small diameter portion 10b3 that fits with the small inner diameter portion 141b. In addition to having annular grooves 10b4 and 10b5 for accommodating the sealing rings 143 and 144 respectively on the outer circumferences of the large diameter portion 10b2 and the small diameter portion 10b3, it also has a structure substantially the same as that of the Figure 6 shown rod guide 10.

[0060] The axial length of the collar 141 is equal to the axial length of the collar fitting portion 10b. The axial length of the large inner diameter portion 141a is greater than the axial length of the large diameter portion 10b2, and the axial length of the small inner diameter portion 141b is less than the axial length of the small diameter portion 10b3. When the collar 141 is fitted into the collar fitting portion 10b of the rod guide 10, the pin 19 mounted on the rod guide 10 is inserted into the pin through-hole 141e and the collar 141 is prevented from rotating. Also, the large inner diameter portion 141a of the collar 141 is fitted with the large diameter portion 10b2 of the collar fitting portion 10b and is in close contact with the sealing ring 143, the small inner diameter portion 141b of the collar 141 is fitted with the small diameter portion 10b3 of the collar fitting portion 10b and is in close contact with the sealing ring 144, and an annular passage G is formed between the inner periphery of the collar 141 and the collar fitting portion 10b. The annular passage G communicates with the internal passage 141c formed in the inner periphery of the collar 141 and communicates with the inside of the liquid storage tank T via the suction pipe 142. Further, since the annular passage G is formed to surround the collar fitting portion 10b, it opens at a position around the rod 2 of the rod guide 10 and extends radially, and can communicate with the internal passage 141c of the collar 141 and the five suction pipes 142 relative to all eight ports 10f leading to the outer periphery of the collar fitting portion 10b. Thus, instead of providing an annular groove on the inner periphery of the collar 141 or the outer periphery of the collar fitting portion 10b, an annular passage G communicating the port 10f and the collar port 14b can be provided by configuring the inner periphery shape of the collar 141 and the outer periphery shape of the collar fitting portion 10b of the rod guide 10 as described above.

[0061] Thus, in the rod guide 10 equipped with Figure 6 the collar 141 shown, an extended side suction passage ES is formed by the suction pipe 142, the internal passage 141c, the annular passage G, and the port 10f, and Figure 1 similar to the shock absorber D shown, a check valve EC is provided on the extended side suction passage ES. Therefore, if the liquid in the extended side chamber R1 is insufficient, the check valve EC opens and liquid is supplied from the liquid storage tank T to the extended side chamber R1 through the extended side suction passage ES.

[0062] Further, when the rod guide 10 equipped with the collar 141 is fitted onto the cylinder 1, the first cylinder 5, and the outer cylinder 4, the collar 141 Figure 1 is the same as the collar 14 shown. By inserting the pin 18 passing through the outer cylinder 4 into the pin insertion groove 141f, rotation in the circumferential direction with respect to the outer cylinder 4 is prevented and it is positioned, and the suction pipe 142 is arranged below the liquid storage tank T. The suction pipe 142 extends from the collar 141 into the liquid storage tank T, and its front end is arranged near the center of the liquid storage tank T. Even if the liquid level in the liquid storage tank T fluctuates due to the vibration generated when the horizontally mounted shock absorber D expands and contracts, the front end of the suction pipe 142 is likely to always be in the liquid, and gas can be prevented from entering the extended side chamber R1.

[0063] Next, the extension side damping valve EV is mounted on the first base 23 through the joint 31, where the first base is mounted on the outer cylinder 4, and the compression side damping valve CV is mounted on the second base 24 through the joint 33, where the second base is mounted on the outer cylinder 4.

[0064] The joint 31 includes: a rectangular bottom plate 31a that abuts against the valve mounting surface 23a on the side of the first base 23 opposite to the outer cylinder; a stepped hole 31b that penetrates the center of the bottom plate 31a and communicates with the hole 23b of the first base 23, and the inner diameter on the side opposite to the outer cylinder is smaller than the inner diameter on the outer cylinder side; an inclined hole 31c that opens from the end surface on the side opposite to the outer cylinder while avoiding the stepped hole 31b and communicates with the hole 23b. Although not shown, the joint 31 configured in this way has through holes at the four corners for allowing bolts to pass through. After overlapping with the first base 23, it is bolted to the first base 23 by combining the bolts (not shown) inserted into the through holes with the screw holes of the first base 23.

[0065] One end of the extension side pipe 32 is fitted into the portion of the stepped hole 31b of the joint 31 with a larger inner diameter. The other end of the extension side pipe 32 is fitted into the first boss portion 5a of the first cylinder 5. Therefore, through the extension side pipe 32, the extension side passage EP between the cylinder 1 and the first cylinder 5 and the inside of the stepped hole 31b are communicated. And the extension side pipe 32 is clamped by the stepped portion of the stepped hole 31b and the step of the continuous hole composed of the first boss portion 5a and the hole 5c of the first cylinder 5, and is fixed to the joint 31 and the first cylinder 5.

[0066] The joint 33 includes: a rectangular bottom plate 33a that abuts against the valve mounting surface 24a on the side of the second base 24 opposite to the outer cylinder; a stepped hole 33b that penetrates the center of the bottom plate 33a and communicates with the hole 24b of the second base 24, and the inner diameter on the side opposite to the outer cylinder is smaller than the inner diameter on the outer cylinder side; an inclined hole 33c that opens from the end surface on the side opposite to the outer cylinder while avoiding the stepped hole 33b and communicates with the hole 24b. Although not shown, the joint 33 configured in this way has through holes at the four corners for allowing bolts to pass through. After overlapping with the second base 24, it is bolted to the second base 24 by combining the bolts (not shown) inserted into the through holes with the screw holes of the second base 24.

[0067] One end of the compression side pipe 34 is fitted onto the portion of the stepped hole 33b of the joint 33 having a larger inner diameter. The other end of the compression side pipe 34 is fitted within the second boss portion 6a of the second cylinder 6. Thus, the compression side passage CP between the connecting cylinder 1 and the second cylinder 6 and the inside of the stepped hole 33b are communicated through the compression side pipe 34. Further, the compression side pipe 34 is clamped by the stepped portion of the stepped hole 33b and the step of the continuous hole formed by the second boss portion 6a of the second cylinder 6 and the hole 6c, and is fixed to the joint 33 and the second cylinder 6.

[0068] In the present embodiment, the extension side damping valve EV includes a valve housing 60 held on the first base 23 by the joint 31, a variable overflow valve 61 provided within the valve housing 60, and a solenoid 62 for adjusting the opening pressure of the variable overflow valve 61.

[0069] The valve housing 60 is fixed to the joint 31 by bolts (not shown) in a state of being in contact with the side surface of the bottom plate 31a of the joint 31 opposite to the first base. Thus, the valve housing 60 is fixed to the first base 23 by the joint 31. Further, the valve housing 60 includes a flow passage 60a having one end communicated with the stepped hole 31b of the joint 31 and the other end communicated with the inclined hole 31c, and the variable overflow valve 61 is provided within the valve housing 60 and in the middle of the flow passage 60a. In the present embodiment, the extension side damping valve EV is connected to the first base 23 via the joint 31. For example, the bottom plate 31a of the joint 31 may be omitted, and a structure in which the extension side pipe 32 is held on the valve housing 60 may be adopted to directly hold the extension side damping valve EV on the first base 23. Alternatively, a structure in which the joint 31 and the valve housing 60 are integrally formed and inseparable may be adopted.

[0070] The variable overflow valve 61 includes a valve body 61a for opening or closing the flow passage 60a, a spring 61b for urging the valve body 61a in a direction to block the flow passage 60a, and a pilot passage 61c for applying pressure in a direction to open the flow passage 60a. The flow passage 60a is communicated with the extension side chamber R1 through the inside of the extension side pipe 32, the extension side passage EP, and the through hole 1f, and is communicated with the reservoir tank T through the inclined hole 31c and the outside of the extension side pipe 32 within the first hole 4a (between the inner circumference of the first hole 4a and the outer circumference of the extension side pipe 32). Further, the pilot passage 61c of the variable overflow valve 61 applies the pressure of the extension side chamber R1 to the valve body 61a in the valve opening direction.

[0071] The solenoid 62 is installed on Figure 3On the left end of the valve housing 60 shown, although not illustrated in detail, it includes a plunger 62a, a coil for driving the plunger 62a, a fixed iron core that attracts the plunger 62a when the coil is excited, and a frame 62b that houses the coil and the fixed iron core. Moreover, when energized, the solenoid 62 drives the plunger 62a in the direction protruding from the frame 62b, applying a thrust force against the spring 61b to the valve body 61a of the variable relief valve 61, thereby pressing the valve body 61a in the valve-opening direction. The solenoid 62 can adjust the magnitude of the thrust force according to the supplied amount of electric current. In addition, the solenoid 62 does not apply a thrust force to the valve body 61a in the non-energized state.

[0072] Therefore, since the solenoid 62 can adjust the magnitude of the thrust force applied to the valve body 61a according to the amount of electric current, it can adjust the magnitude of the valve-opening pressure of the variable relief valve 61. In the present embodiment, if the variable relief valve 61 sets the amount of electric current supplied to the solenoid 62 to the maximum, the valve-opening pressure is set to the minimum, and if no power is supplied to the solenoid 62, the valve-opening pressure is set to the maximum. Therefore, the variable relief valve 61 can control the pressure in the upstream extension-side chamber R1 communicated by the extension-side passage EP by the amount of electric current supplied to the solenoid 62.

[0073] In the present embodiment, the compression-side damping valve CV includes a valve housing 63 held on the second base 24 by a joint member 33, a variable relief valve 64 provided inside the valve housing 63, and a solenoid 65 that adjusts the valve-opening pressure of the variable relief valve 64.

[0074] The valve housing 63 is fixed to the joint member 33 by bolts (not shown) in a state where it abuts against the side of the bottom plate 33a of the joint member 33 opposite to the second base. Therefore, the valve housing 63 is fixed to the second base 24 by the joint member 33. Moreover, the valve housing 63 has a flow passage 63a with one end communicating with the stepped hole 33b of the joint member 33 and the other end communicating with the inclined hole 33c, and the variable relief valve 64 is provided inside the valve housing 63 and in the middle of the flow passage 63a. And in the present embodiment, the compression-side damping valve CV is connected to the second base 24 by the joint member 33. For example, the bottom plate 33a of the joint member 33 can be omitted, and a structure in which the compression-side pipe 34 is held on the valve housing 63 can be adopted to directly hold the compression-side damping valve CV on the second base 24, or a structure in which the joint member 33 and the valve housing 63 are integrally formed and inseparable can also be adopted.

[0075] The variable overflow valve 64 includes a valve body 64a that opens or closes the flow path 63a, a spring 64b that biases the valve body 64a in the direction of blocking the flow path 63a, and a pilot passage 64c that applies pressure in the direction of opening the flow path 63a. The flow path 63a communicates with the compression side chamber R2 through the inside of the compression side pipe 34, the compression side passage CP, and the through hole 1g, and communicates with the liquid storage tank T through the inclined hole 33c and the second hole 4b and outside the compression side pipe 34 (between the inner periphery of the second hole 4b and the outer periphery of the compression side pipe 34). Moreover, the pilot passage 64c of the variable overflow valve 64 causes the pressure in the compression side chamber R2 to act on the valve body 64a in the valve opening direction.

[0076] The solenoid 65 is installed on Figure 3 the left end of the valve housing 63 shown. Although not shown in detail, it includes a plunger 65a, a coil that drives the plunger 65a, a fixed iron core that attracts the plunger 65a when the coil is excited, and a frame 65b that houses the coil and the fixed iron core. Moreover, when energized, the solenoid 65 drives the plunger 65a in the direction of protruding from the frame 65b, applies a thrust force that counteracts the spring 64b to the valve body 64a of the variable overflow valve 64, and thus presses the valve body 64a in the valve opening direction. The solenoid 65 can adjust the magnitude of the thrust force according to the supplied amount of electric current. In addition, the solenoid 65 does not apply a thrust force to the valve body 64a in the non-energized state.

[0077] Therefore, since the solenoid 65 can adjust the magnitude of the thrust force applied to the valve body 64a according to the amount of electric current, it is possible to adjust the magnitude of the valve opening pressure of the variable overflow valve 64. In the present embodiment, if the amount of electric current supplied to the solenoid 65 is set to the maximum, the valve opening pressure of the variable overflow valve 64 is set to the minimum, and if no power is supplied to the solenoid 65, the valve opening pressure is set to the maximum. Therefore, the variable overflow valve 64 can control the pressure in the upstream compression side chamber R2 communicated with by the compression side passage CP by the amount of electric current supplied to the solenoid 65.

[0078] The shock absorber D is configured as described above. Hereinafter, the operation of the shock absorber D will be described. First, the operation when the shock absorber D extends will be described. When the shock absorber D performs an extension operation, the piston 3 moves relative to the cylinder 1 in the Figure 1It moves leftward in the middle, so the expansion side chamber R1 shrinks, and the compression side chamber R2 expands. Since the shrunk expansion side chamber R1 is communicated with the liquid storage tank T through the expansion side passage EP and the expansion side damping valve EV, the liquid in the expansion side chamber R1 is discharged to the liquid storage tank T through the expansion side passage EP and the expansion side damping valve EV. Since resistance can be applied to such liquid movement through the variable overflow valve 61, the pressure of the expansion side chamber R1 is adjusted to be greater than the pressure of the liquid storage tank T and equal to the opening pressure of the variable overflow valve 61. In addition, the compression side chamber R2, whose volume expands due to the movement of the piston 3, lacks liquid, but the insufficient part of the liquid can be supplied to the compression side chamber R2 from the liquid storage tank T via the compression side suction passage CS by opening the compression side check valve 15. Therefore, the pressure of the compression side chamber R2 is approximately equal to the pressure of the liquid storage tank T.

[0079] Thus, when the shock absorber D performs an extension operation, the pressure of the expansion side chamber R1 acting on the side of the expansion side chamber of the piston 3 is greater than the pressure of the compression side chamber R2 acting on the side of the compression side chamber of the piston 3, and the shock absorber D generates an expansion side damping force that hinders its own extension operation. In addition, since the opening pressure of the variable overflow valve 61 can be adjusted in magnitude according to the amount of current supplied to the solenoid 62, the magnitude of the expansion side damping force generated when the shock absorber D performs an extension operation can be adjusted through the expansion side damping valve EV.

[0080] Next, the contraction operation of the shock absorber D will be described. When the shock absorber D performs a contraction operation, the piston 3 moves Figure 1 rightward in it, so the compression side chamber R2 shrinks, and the expansion side chamber R1 expands. Since the shrunk compression side chamber R2 is communicated with the liquid storage tank T through the compression side passage CP and the compression side damping valve CV, the liquid in the compression side chamber R2 is discharged to the liquid storage tank T through the compression side passage CP and the compression side damping valve CV. Since resistance can be applied to such liquid movement through the variable overflow valve 64, the pressure of the compression side chamber R2 is adjusted to be greater than the pressure of the liquid storage tank T and equal to the opening pressure of the variable overflow valve 64. In addition, the expansion side chamber R1, whose volume expands due to the movement of the piston 3, lacks liquid, and the insufficient part of the liquid can be supplied to the expansion side chamber R1 from the liquid storage tank T via the expansion side suction passage ES by opening the check valve EC. Therefore, the pressure of the expansion side chamber R1 is approximately equal to the pressure of the liquid storage tank T.

[0081] When the shock absorber D contracts in this manner, the pressure in the compression-side chamber R2 acting on the side surface of the compression-side chamber of the piston 3 is greater than the pressure in the extension-side chamber R1 acting on the side surface of the extension-side chamber of the piston 3. The shock absorber D generates a compression-side damping force that hinders its own contraction work. In addition, since the opening pressure of the variable overflow valve 64 can be adjusted in magnitude according to the amount of current supplied to the solenoid 65, the magnitude of the compression-side damping force generated when the shock absorber D contracts can be adjusted by the compression-side damping valve CV.

[0082] When the shock absorber D extends, since the extension-side damping valve EV applies resistance to the flow of the liquid from the extension-side chamber R1 toward the liquid storage tank T, only the liquid in the extension-side chamber R1 is compressed to generate an extension-side damping force. Therefore, even when the liquid column compression rigidity increases and the extension work is performed at an extremely low speed, a damping force of sufficient magnitude can be generated without causing insufficient damping force. In addition, when the shock absorber D contracts, since the compression-side damping valve CV applies resistance to the flow of the liquid from the compression-side chamber R2 toward the liquid storage tank T, only the liquid in the compression-side chamber R2 is compressed to generate a compression-side damping force. Therefore, even when the contraction work is performed at an extremely low speed, a damping force of sufficient magnitude can be generated without causing insufficient damping force.

[0083] In addition, since the shock absorber D generates an extension-side damping force using the extension-side damping valve EV and a compression-side damping force using the compression-side damping valve CV, the restriction that the cross-sectional area of the rod 2 must be half of the cross-sectional area of the piston 3 is eliminated. Therefore, considering strength, while making the outer diameter of the rod 2 as small as possible, the inner diameter of the cylinder 1 can be increased as much as possible to increase the compression-side damping force generated when the shock absorber D contracts.

[0084] And, as described above, when the shock absorber D contracts, liquid is supplied from the liquid storage tank T to the extension-side chamber R1 through the extension-side suction passage ES. However, if the cross-sectional area of the rod 2 is reduced and the inner diameter of the cylinder 1 is increased to increase the compression-side damping force of the shock absorber D, the amount of liquid supplied from the liquid storage tank T to the extension-side chamber R1 should be increased when the shock absorber D contracts.

[0085] On the contrary, in the shock absorber D of the present embodiment, since the extension-side check valve 13 opens or closes a plurality of ports 10f provided around the rod 2 of the rod guide 10 using the annular valve body 13a disposed on the outer periphery of the rod 2, an extension-side suction passage ES with a sufficiently ensured flow path area can be formed with respect to the small rod guide 10.

[0086] Therefore, even for the shock absorber D in which the cross-sectional area of the rod 2 is reduced and the inner diameter of the cylinder 1 is increased in order to increase the compression-side damping force when the shock absorber D contracts in the extremely low speed range, an elongation-side suction passage ES with a sufficiently large flow path area can be formed on the rod guide 10 during high-speed contraction. Therefore, poor liquid supply does not occur in the elongation-side chamber R1.

[0087] As described above, the shock absorber D of the present embodiment includes: a cylinder 1; a rod 2 that is axially movably inserted into the cylinder 1; a piston 3 that is movably inserted into the cylinder 1 and is connected to the rod 2 to divide the inside of the cylinder 1 into an elongation-side chamber R1 and a compression-side chamber R2; an outer cylinder 4 that covers the cylinder 1 and forms a liquid reservoir T for storing liquid on the outer periphery of the cylinder 1; a ring-shaped rod guide 10 that supports the rod 2, having a cylinder fitting portion 10d that fits into the inner periphery of one end of the cylinder 1, an end portion facing the elongation-side chamber R1 opposite to the cylinder fitting portion 10d, that is, a ring-shaped end portion 10d1 that surrounds the rod 2, and an outer cylinder fitting portion 10a that fits into the inner periphery of one end of the outer cylinder 4; and a check valve EC that allows only the flow of liquid from the liquid reservoir T to the elongation-side chamber R1. The check valve EC includes: a plurality of ports 10f that are arranged side by side in the circumferential direction at one end and are respectively communicated with the liquid reservoir T; a ring-shaped valve body 13a that can approach or move away from the ring-shaped end portion 10d1 in the axial direction so as to open or close each port 10f; and a helical spring (spring) 13c that applies a force to the valve body 13a toward the ring-shaped end portion 10d1.

[0088] In the shock absorber D configured in this manner, the check valve EC has a plurality of ports 10f that are arranged side by side in the circumferential direction on the annular end portion 10d1 around the rod member 2 of the rod guide member 10. Since the open ends of the ports 10f are opened or closed by the annular valve body 13a that approaches or moves away from the annular end portion 10d1, a plurality of ports 10f can be efficiently arranged on the small rod guide member 10 to ensure that all the ports 10f have a large total flow path area. Even if the liquid flow rate from the liquid reservoir T to the extension side chamber R1 is large, the liquid can be allowed to flow from the liquid reservoir T to the extension side chamber R1 without generating too much resistance thereto. Therefore, when the extension side suction passage ES that connects the extension side chamber R1 and the liquid reservoir T is provided, since a plurality of ports 10f are provided around the rod member 2 of the rod guide member 10 that is inserted through the center and fitted to the cylinder 1 to ensure the flow path area, a large flow rate of liquid can be supplied from the liquid reservoir T to the extension side chamber R1, and there will be no shortage of liquid supply in the extension side chamber R1. In addition, the valve body 13a is provided in the extension side chamber R1 instead of in the rod guide member 10. Since all the ports 10f can be opened or closed by one valve body 13a, the size of the rod guide member 10 will not increase, the outer diameter of the rod member will not decrease, or the inner diameter of the outer cylinder will not increase. As described above, in the shock absorber D according to the present embodiment, even if the check valve EC is provided on the rod guide member 10, a large flow rate can be allowed to pass through. Therefore, there will be no shortage of liquid supply in the extension side chamber R1, bubbles generated in the cylinder 1 can be suppressed, and a stable damping force can be generated. Further, in the shock absorber D according to the present embodiment, since the size of the check valve EC will not increase, its mounting performance will not be impaired either.

[0089] Moreover, in the shock absorber D of the present embodiment, the check valve EC includes: an annular collar 14 that is fitted on the outer circumference between the outer cylinder fitting portion 10a and the cylinder fitting portion 10d of the rod guide member 10 and is accommodated in the outer cylinder 4; an annular passage 10b1 that is formed in the circumferential direction between the rod guide member 10 and the collar 14, and the other ends of the respective ports 10f communicate with the annular passage 10b1. The collar 14 has a notch 14a provided on a part of the outer circumference and a plurality of collar ports 14b that open from the notch 14a and communicate with the annular passage 10b1. In the shock absorber D configured in this manner, even if a plurality of ports 10f are arranged around the rod member 2 of the rod guide member 10, since the check valve EC can prevent gas from being mixed into the liquid reservoir T by arranging the notch 14a of the collar 14 below the liquid reservoir T and supply only the liquid to the extension side chamber R1, it is suitable for lateral use to suppress the horizontal lateral vibration of the body of a railway vehicle.

[0090] In addition, the shock absorber D of the present embodiment includes: an annular collar 141 that is fitted on the outer periphery between the outer cylinder fitting portion 10a and the cylinder fitting portion 10d of the rod guide 10 and is accommodated in the outer cylinder 4; and an annular passage G that is formed in the circumferential direction between the rod guide 10 and the collar 141. The other ends of the respective ports 10f communicate with the annular passage G. The collar 141 has an internal passage 141c that connects the inside of the plurality of suction pipes 142 to the annular passage G. These suction pipes are accommodated in the liquid storage tank T and their proximal ends are fitted in the collar 141. According to the shock absorber D configured in this way, even if a plurality of ports 10f are arranged around the rod 2 of the rod guide 10, by arranging the suction pipes 142 provided on the collar 141 below the liquid storage tank T, the check valve EC can prevent gas from mixing into the liquid storage tank T and supply only the liquid to the extension side chamber R1. Further, in the shock absorber D of the present embodiment, since the front ends of the suction pipes 142 are arranged near the center below the inside of the liquid storage tank T, even if the shock absorber D vibrates and causes fluctuations in the liquid level of the liquid in the liquid storage tank T, the front ends of the suction pipes 142 are likely to always be in the liquid, effectively preventing gas from mixing into the extension side chamber R1, and is most suitable for horizontal installation to suppress the horizontal lateral vibration of the body of a railway vehicle.

[0091] Moreover, in the shock absorber D of the present embodiment, the rod guide 10 has a cylindrical valve mounting portion 10e that projects axially from the annular end portion 10d1, and an annular valve seat 10d2 that surrounds the outer periphery of each port 10f that opens on the outer peripheral side of the valve mounting portion 10e. The valve body 13a is in sliding contact with the outer periphery of the valve mounting portion 10e. In the shock absorber D configured in this way, since the valve body 13a can approach or move away from the annular end portion 10d1 without axial jitter relative to the valve mounting portion 10e, the valve body 13a can seat and unseat facing the entire annular valve seat 10d2. Therefore, even if a plurality of ports 10f open on the annular end portion 10d1 of the rod guide 10, all the ports 10f can be stably closed simultaneously, and when opening the valve, it can also quickly move away from the annular valve seat 10d2 without imposing an excessive resistance on the flow of the liquid flowing through the ports 10f.

[0092] In addition, the shock absorber D of the present embodiment includes: a first cylinder 5 disposed on the outer peripheral side of the cylinder 1, and an extension side passage EP communicating with the extension side chamber R1 is formed between the first cylinder 5 and the cylinder 1; a second cylinder 6 disposed on the outer peripheral side of the cylinder 1 and a compression side passage CP communicating with the compression side chamber R2 is formed between the second cylinder 6 and the cylinder 1; an extension side damping valve EV that applies resistance to the flow of the liquid from the extension side chamber R1 toward the liquid storage tank T through the extension side passage EP; a compression side damping valve CV that applies resistance to the flow of the liquid from the compression side chamber R2 toward the liquid storage tank T through the compression side passage CP; a valve housing 9 fitted to the other end of the cylinder 1 and the second cylinder 6, and the rod guide 10 has a first cylinder fitting portion 10c that fits the first cylinder 5 between the cylinder fitting portion 10d and the outer cylinder fitting portion 10a. Among them, the first cylinder 5 and the second cylinder 6 are clamped by the rod guide 10 and the valve housing 9. According to the shock absorber D configured in this way, since the first cylinder 5 and the second cylinder 6 are clamped by the rod guide 10 and the valve housing 9, the first cylinder 5 and the second cylinder 6 can be joined together without welding or screwing. Therefore, the installation property can be improved while reducing the processing cost. Moreover, by making the end portions 5d and 6d abut against each other and being clamped by the rod guide 10 and the valve housing 9, they can be fixed to the outer periphery of the cylinder 1 without play.

[0093] Furthermore, according to the shock absorber D of the present embodiment, since the first cylinder 5 and the second cylinder 6 can be fitted to the outer periphery of the cylinder 1 from both sides of the cylinder 1, compared with the case where the first cylinder 5 and the second cylinder 6 are formed by a single pipe, when assembling the shock absorber D, the sealing rings 20 and 21 between the cylinder 1 and the first cylinder 5 and the second cylinder 6 will not be damaged or worn. Also, the first cylinder 5 and the second cylinder 6 can separate the opposite end portions 5d and 6d from each other. However, as described above, by making the end portions 5d and 6d abut against each other and being clamped by the rod guide 10 and the valve housing 9, they can be fixed to the outer periphery of the cylinder 1 without play, which is advantageous.

[0094] In addition, the shock absorber D according to the present embodiment is provided with a check valve EC. Therefore, even when the contraction operation is performed at high speed, the check valve EC allows a large flow rate. So, insufficient liquid supply will not occur in the extension side chamber R1, the generation of air bubbles in the cylinder 1 can be suppressed, and a stable damping force can be generated.

[0095] In addition, when the shock absorber D according to the present embodiment performs an extension operation, the extension side damping valve EV applies resistance to the flow of the liquid from the extension side chamber R1 toward the liquid storage tank T, and only the liquid in the extension side chamber R1 is compressed to generate an extension side damping force. Therefore, the liquid column compression rigidity can be improved. Thus, according to the shock absorber D of the present embodiment, the liquid column compression rigidity during the extension operation can be improved, so that sufficient damping force can be generated even when the extension operation is performed at an extremely low speed.

[0096] Furthermore, in the shock absorber D according to the present embodiment, the extension-side passage EP and the compression-side passage CP are respectively formed by the first cylinder 5 and the second cylinder 6 disposed on the outer periphery of the cylinder 1 and can rotate relative to each other circumferentially before being fixed. Therefore, the extension-side passage EP and the compression-side passage CP can be provided on the outer periphery of the cylinder 1 without significantly reducing the volume in the reservoir T, and the circumferential arrangement of the first cylinder 5 and the circumferential arrangement of the second cylinder 6 can be set independently of each other. Thus, the outlet of the extension-side passage EP and the extension-side damper valve EV can be arranged very close to each other, shortening the length of the pipeline connecting the two. Also, the outlet of the compression-side passage CP and the compression-side damper valve CV can be arranged very close to each other, shortening the length of the pipeline connecting the two (the total length of the extension-side pipe 32 and the total length of the compression-side pipe 34).

[0097] In this way, in the shock absorber D according to the present embodiment, since the first cylinder 5 and the second cylinder 6 on the outer periphery of the cylinder 1 can rotate relative to each other circumferentially before being fixed, even if the installation positions of the extension-side damper valve EV and the compression-side damper valve CV relative to the outer cylinder 4 are changed according to the equipment on which the shock absorber D is installed, the outlet of the extension-side passage EP and the extension-side damper valve EV can be arranged very close to each other, and at the same time, the outlet of the compression-side passage CP and the compression-side damper valve CV can be arranged very close to each other. In summary, even if the installation positions of the extension-side damper valve EV and the compression-side damper valve CV relative to the outer cylinder 4 are changed, the length of the pipeline can be shortened. Therefore, the proportion of the volume reduction in the reservoir T through this pipeline also becomes smaller, and in order to ensure the volume in the reservoir T, the diameter of the outer cylinder 4 will not become significantly thicker. Thus, in the shock absorber D according to the present embodiment, the installation positions of the extension-side damper valve EV and the compression-side damper valve CV on the outer cylinder 4 can be easily changed according to the equipment without causing an increase in the size of the shock absorber D, so the mounting performance and practicality on the equipment can be improved.

[0098] In addition, in the shock absorber D of the present embodiment, the cylinder 1 is provided with an extension-side recess 1d on the outer periphery and forms the extension-side passage EP between the cylinder 1 and the first cylinder 5, a compression-side recess 1e on the outer periphery and forms the compression-side passage CP between the cylinder 1 and the second cylinder 6, and a convex portion 1c that protrudes radially outward between the extension-side recess 1d and the compression-side recess 1e to separate the extension-side recess 1d and the compression-side recess 1e. In the shock absorber D configured in this way, if the extension-side recess 1d and the compression-side recess 1e are machined on the outer periphery of the cylinder 1, the extension-side passage EP between the cylinder 1 and the first cylinder 5 and the compression-side passage CP between the cylinder 1 and the second cylinder 6 can be formed. Therefore, compared with the case where recesses are formed on the inner circumferences of the first cylinder 5 and the second cylinder 6 to form the extension-side passage EP and the compression-side passage CP, the machining is easier and the machining cost can be reduced.

[0099] Further, in the shock absorber D of the present embodiment, a head-side flange 1a and a bottom-side flange 1b are provided at the ends of the cylinder 1, but these head-side flange 1a and bottom-side flange 1b may be omitted. However, since the cylinder 1 is provided with the head-side flange 1a and the bottom-side flange 1b, there is an advantage that loosening is less likely to occur between the cylinder 1 and the first cylinder 5 and the second cylinder 6.

[0100] Furthermore, in the shock absorber D of the present embodiment, the outer cylinder 4 has a first hole 4a and a second hole 4b that communicate the inside and the outside. The first cylinder 5 has an annular first boss portion 5a that faces the first hole 4a and whose inner circumference communicates with the extension-side passage EP. The second cylinder 6 has an annular second boss portion 6a that faces the second hole 4b and whose inner circumference communicates with the compression-side passage CP. The extension-side damper valve EV provided outside the outer cylinder 4 is communicated with the extension-side passage EP through an extension-side pipe 32 inserted into the first hole 4a and the first boss portion 5a, and the extension-side damper valve EV is communicated with the reservoir tank T through the inside of the first hole 4a and the outside of the extension-side pipe 32. The compression-side damper valve CV provided outside the outer cylinder 4 is communicated with the compression-side passage CP through a compression-side pipe 34 inserted into the second hole 4b and the second boss portion 6a, and the compression-side damper valve CV is communicated with the reservoir tank T through the inside of the second hole 4b and the outside of the compression-side pipe 34.

[0101] According to the shock absorber D configured in this way, since the first cylinder 5 and the second cylinder 6 on the outer circumference of the cylinder 1 can rotate relative to each other in the circumferential direction before being fixed, the first boss portion 5a can be arranged at a position extremely close to the extension-side damper valve EV, and the second boss portion 6a can be arranged at a position extremely close to the compression-side damper valve CV, so that the extension-side pipe 32 and the compression-side pipe 34 that reduce the volume in the reservoir tank T can be shortened. The first hole 4a and the second hole 4b can be used as passages to return the liquid passing through the extension-side damper valve EV and the compression-side damper valve CV to the reservoir tank T. Further, since the first cylinder 5 is provided with the first boss portion 5a and the second cylinder 6 is provided with the second boss portion 6a, in order to install the extension-side pipe 32 and the compression-side pipe 34, it is not necessary to thicken the walls of the entire lengths of the first cylinder 5 and the second cylinder 6, and the volume in the reservoir tank T can be ensured without significantly increasing the diameter of the outer cylinder 4. In addition, according to the shock absorber D of the present embodiment, since the first cylinder 5 is provided with the first boss portion 5a and the second cylinder 6 is provided with the second boss portion 6a, the extension-side pipe 32 and the compression-side pipe 34 are easier to install, and the assembly work of the shock absorber D is simpler.

[0102] Further, in the shock absorber D of the present embodiment, the first cylinder 5 and the second cylinder 6 have opposite end portions 5d and 6d butted and abutted against each other, and at the same time, flat surfaces 5b and 6b for circumferential alignment are provided on the outer circumferences of the opposite end portions 5d and 6d, and permanent magnets 40 are mounted on the flat surfaces 5b and 6b. According to the shock absorber D configured in this way, since the permanent magnets 40 are provided on the flat surfaces 5b and 6b provided on the outer circumferences of the first cylinder 5 and the second cylinder 6, it is possible to capture contaminants such as chips generated when machining the components constituting the shock absorber D in the liquid in the liquid reservoir T with the permanent magnets 40, clean the liquid, and suppress the entrainment of contaminants caused by the extension-side damping valve EV, the compression-side damping valve CV, the extension-side check valve 13, and the compression-side check valve 15. In addition, since the permanent magnets 40 are mounted on the flat surfaces 5b and 6b, and the flat surfaces are marks for circumferential alignment of the first cylinder 5 and the second cylinder 6, there is no risk of the permanent magnets 40 falling off from the first cylinder 5 and the second cylinder 6. When installing the permanent magnets 40, the operator visually observes the positions of the flat surfaces 5b and 6b, so that the first cylinder 5 and the second cylinder 6 can be accurately arranged in appropriate positions.

[0103] Moreover, the extension-side damping valve EV and the compression-side damping valve CV are provided with variable overflow valves 61 and 64 and are damping valves with adjustable damping force. However, when the shock absorber D does not require adjustment of the damping force, it may also be a damping valve that cannot adjust the damping force.

[0104] The preferred embodiments of the present invention have been described in detail above, but they can be modified, deformed, and changed as long as they do not depart from the scope of the claims.

[0105] Symbolic description

[0106] 1 Cylinder

[0107] 2 Rod

[0108] 3 Piston

[0109] 4 Outer cylinder

[0110] 10 Rod guide

[0111] 10a Outer cylinder fitting portion

[0112] 10b1, G annular passage

[0113] 10d Cylinder fitting portion

[0114] 10d1 Annular end

[0115] 10d2 Annular valve seat

[0116] 10e Valve mounting portion

[0117] 13a Valve body

[0118] 13c spring

[0119] 14, 141 collar

[0120] 14a notch

[0121] 14b collar port

[0122] 141c internal passage

[0123] 142 suction pipe

[0124] CS compression side suction channel

[0125] CV compression side damping valve

[0126] D shock absorber

[0127] EC check valve

[0128] EV extension side damping valve

[0129] R1 extension side chamber

[0130] R2 compression side chamber

[0131] T liquid storage tank

Claims

1. A shock absorber, wherein: have: cylinder; A rod member, which is movably inserted into the cylinder along the axial direction; A piston, which is movably inserted into the cylinder and connected to the rod, dividing the interior of the cylinder into an extension side chamber and a compression side chamber; An outer cylinder, which covers the cylinder and forms a liquid storage tank for storing liquid on the outer periphery of the cylinder; an annular rod guide for supporting the rod, comprising a cylinder fitting portion fitted into the inner periphery of one end of the cylinder, an end portion of the extension side chamber facing the cylinder fitting portion, i.e., an annular end portion surrounding the circumference of the rod, and an outer tube fitting portion fitted into the inner periphery of one end of the outer tube; and a check valve disposed on the rod guide to allow only the flow of liquid from the liquid reservoir to the extension side chamber; The check valve has: A plurality of ports are opened side by side at one end along the circumferential direction at the annular end and are respectively connected to the liquid storage tank; An annular valve body that can be moved closer to or farther from the annular end in the axial direction, thereby opening or closing each port; A spring biases the valve body toward the annular end.

2. The shock absorber according to claim 1, wherein: The check valve has: an annular collar fitted on the outer periphery between the outer tube fitting portion and the cylinder fitting portion of the rod guide and accommodated in the outer tube; and an annular channel formed circumferentially between the rod guide and the collar, The other end of each port is connected to the annular channel. The collar has a cutout disposed on a portion of an outer circumference, and a plurality of collar ports opening from the cutout and communicating with the annular channel.

3. The shock absorber according to claim 1, wherein: The check valve has: an annular collar fitted on the outer periphery between the outer tube fitting portion and the cylinder fitting portion of the rod guide and accommodated in the outer tube; and an annular channel formed circumferentially between the rod guide and the collar, The other end of each port is connected to the annular channel. The collar has an internal passage that connects the interior of a plurality of suction tubes to the annular passage. The suction tubes are accommodated in the liquid storage tank and have their base ends fitted in the collar.

4. The shock absorber according to claim 1, wherein: The rod guide has a cylindrical valve mounting portion protruding in the axial direction from the annular end portion, and an annular valve seat surrounding the outer periphery of each port opened on the outer peripheral side of the valve mounting portion. The valve body is in sliding contact with the outer periphery of the valve mounting portion.

5. The shock absorber according to any one of claims 1 to 4, wherein: have: A first tube, which is arranged on the outer peripheral side of the cylinder and forms an extension side passage communicating with the extension side chamber between the first tube and the cylinder; a second cylinder, which is disposed on the outer peripheral side of the cylinder and forms a compression side passage communicating with the compression side chamber between the second cylinder and the cylinder; an extension-side damping valve that applies resistance to the flow of liquid from the extension-side chamber to the liquid reservoir through the extension-side passage; and a compression-side damping valve that applies resistance to the flow of liquid from the compression-side chamber to the liquid storage tank through the compression-side passage; A valve housing engaged with the other end of the cylinder and the second cylinder, The rod guide includes a first tube fitting portion for fitting the first tube between the cylinder fitting portion and the outer tube fitting portion. The first cylinder and the second cylinder are sandwiched by the rod guide and the valve housing.

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