Shock absorber

Abstract

A damper (D) is provided with a cylinder (1), a rod (2) inserted into the 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), a first cylinder (5) that forms an extension-side passage (EP) between the cylinder (1) and the first cylinder (5), and a second cylinder (6) that forms a compression-side passage (CP) between the cylinder (1) and the second cylinder (6). A liquid storage tank T for storing liquid is formed between the outer cylinder 4 and the first cylinder 5 and the second cylinder 6. An extension-side suction channel ES for allowing only liquid flowing from the liquid storage tank T to the extension-side chamber R1 to flow, and a compression-side suction channel CS for allowing only liquid flowing from the liquid storage tank T to the compression-side chamber R2 to flow are formed between the outer cylinder 4 and the first cylinder 5 and the second cylinder 6. An extension-side damper valve EV that imparts resistance to the flow of liquid from the extension-side chamber R1 toward the reservoir T through the extension-side passage EP; and a compression-side damper valve CV that imparts resistance to the flow of liquid from the compression-side chamber R2 toward the reservoir T through the compression-side passage CP.

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 vibrations 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 vibrations in the left - right direction with respect to the traveling direction of the car body.

[0003] As shown in Japanese Patent JP2016 - 84841A, 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 guide member that closes one end of the cylinder and one end of the outer tube and has the rod inserted through its inner circumference; a bottom cover that closes the other end of the cylinder and the other end of the outer tube; and a valve assembly that has a passage that is held on the bottom cover and connects the rod - side chamber and the liquid reservoir and a variable overflow valve provided in the middle of the passage (for example, refer to Patent Document 1). Summary of the Invention

[0004] Problems to be Solved by the Invention

[0005] In a conventional shock absorber, in order to suppress vibrations in the left - right direction of a railway vehicle, with the opening pressure of the variable overflow valve remaining unchanged, if the stroke speed is the same, the damping forces on both the extending and contracting sides are set to be equal. Therefore, in a conventional shock absorber, in order to ensure that, regardless of whether it is extending or contracting, as long as the stroke amount is the same, the amount of hydraulic oil discharged from the cylinder to the liquid reservoir and passing through the variable overflow valve is equal, the cross - sectional area of the rod has always been one - half of the cross - sectional area of the piston.

[0006] In addition, due to the structure of a conventional shock absorber, when performing a contracting operation, the rod intrudes into the cylinder, causing the entire cylinder to pressurize and generating a damping force that hinders the contracting operation. Therefore, the total amount of hydraulic oil in the cylinder is compressed during the contracting operation.

[0007] In a conventional shock absorber configured in this way, when the stroke speed is high to a certain extent during the contracting operation, a damping force can be smoothly generated. However, since gas is dissolved in the hydraulic oil filled in the shock absorber and the hydraulic oil exhibits elasticity, when the stroke is performed at an extremely low speed during the contracting operation, the damping force may sometimes be insufficient.

[0008] To avoid this phenomenon, it is possible to consider increasing the inner diameter of the cylinder to increase the pressure-receiving area of the piston. However, in many cases, due to the limited space for setting the shock absorber, it is impossible to increase the outer diameter of the shock absorber. In addition, as described above, in a conventional shock absorber, if the inner diameter of the cylinder is increased, the outer diameter of the rod must also be increased, making it difficult to increase the damping force generated during contraction at an extremely low speed.

[0009] Therefore, an object of the present invention is to provide a shock absorber that can generate sufficient damping force even when contracting at an extremely low speed.

[0010] [Means for Solving the Problem]

[0011] 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 and is connected to the rod to divide the inside of the cylinder into an extension-side chamber and a compression-side chamber; a first cylinder that is disposed on the outer peripheral side of the cylinder and forms an extension-side passage communicating with the extension-side chamber between the first cylinder and the cylinder; a second cylinder that 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 outer cylinder that is disposed on the outer peripheral side of the first cylinder and the second cylinder and forms a liquid storage tank for storing liquid between the outer cylinder and the first cylinder and the second cylinder; an extension-side suction passage that allows only the liquid to flow from the liquid storage tank to the extension-side chamber; a compression-side suction passage that allows only the liquid to flow from the liquid storage tank to the compression-side chamber; an extension-side damping valve that applies resistance to the flow of the liquid flowing from the extension-side chamber to the liquid storage tank through the extension-side passage; and a compression-side damping valve that applies resistance to the flow of the liquid flowing from the compression-side chamber to the liquid storage tank through the compression-side passage.

[0012] According to the shock absorber configured as described above, during the extension operation, since resistance is applied to the flow of the liquid flowing from the extension-side chamber to the liquid storage tank by the extension-side damping valve, only the liquid in the extension-side chamber is compressed to generate an extension-side damping force. Therefore, the liquid column compression rigidity can be improved. In addition, in the shock absorber of the present embodiment, during the extension operation, since resistance is applied to the flow of the liquid flowing from the extension-side chamber to the liquid storage tank by the extension-side damping valve, only the liquid in the extension-side chamber is compressed to generate an extension-side damping force. During the contraction operation, resistance is applied to the flow of the liquid flowing from the compression-side chamber to the liquid storage tank by the compression-side damping valve, and only the liquid in the compression-side chamber is compressed to generate a compression-side damping force. The outer diameter of the rod and the inner diameter of the cylinder are not limited as in the conventional shock absorber. As long as there are no strength problems, the inner diameter of the cylinder can be increased while reducing the outer diameter of the rod.

[0013] As described above, the shock absorber according to the present invention can increase the liquid column compression rigidity during the extension operation while reducing the outer diameter of the rod. Therefore, sufficient damping force can be generated even during the extension operation at an extremely low speed. In addition, in the shock absorber according to the present invention, the extension side passage and the compression side passage are respectively formed by the first cylinder and the second cylinder arranged on the outer periphery of the cylinder, and can rotate relative to each other in the circumferential direction before being fixed. Therefore, even if the installation positions of the extension side damping valve and the compression side damping valve relative to the outer cylinder are changed according to the equipment on which the shock absorber is installed, the outlet of the extension side passage and the extension side damping valve can be arranged very close to each other, and at the same time, the outlet of the compression side passage and the compression side damping valve can be arranged very close to each other. It is easy to change the installation positions of the extension side damping valve and the compression side damping valve relative to the outer cylinder according to the equipment without increasing the size of the shock absorber. Therefore, the mounting performance and practicality on the equipment can be improved. [Description of Drawings]

[0014] Figure 1 It is a cross-sectional view of the shock absorber in one embodiment cut vertically along the axis.

[0015] Figure 2 It is a perspective view of the first cylinder and the second cylinder of the shock absorber in one embodiment.

[0016] Figure 3 It is a cross-sectional view of the shock absorber in one embodiment cut horizontally along the axis.

[0017] Figure 4 It is a longitudinal cross-sectional view of a modified example of the guide member and the collar. [Detailed Embodiments]

[0018] The present invention will be described below based on the embodiments shown in the drawings. As Figure 1As shown in the figure, 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 extension side chamber R1 and a compression side chamber R2; a first cylinder 5 that is disposed on the outer peripheral side of the cylinder 1 and forms an extension side passage EP communicating with the extension side chamber R1 between the first cylinder 5 and the cylinder 1; a second cylinder 6 that is disposed on the outer peripheral side of the cylinder 1 and forms a compression side passage CP communicating with the compression side chamber R2 between the second cylinder 6 and the cylinder 1; an outer cylinder 4 that is disposed on the outer peripheral sides of the first cylinder 5 and the second cylinder 6 and forms a liquid storage tank T for storing liquid between the outer cylinder 4 and the first cylinder 5 and the second cylinder 6; an extension side suction passage ES that only allows the liquid to flow from the liquid storage tank T to the extension side chamber R1; a compression side suction passage CS that only allows the liquid to flow from the liquid storage tank T to the compression side chamber R2; an extension side damping valve EV that applies resistance to the flow of the liquid flowing from the extension side chamber R1 to the liquid storage tank T through the extension side passage EP; and a compression side damping valve CV that applies resistance to the flow of the liquid flowing from the compression side chamber R2 to the liquid storage tank T through the compression side passage CP. Although not shown in detail, the shock absorber D of the present embodiment is clamped between the body and the bogie of a railway vehicle, and the damping force generated during telescoping suppresses the horizontal lateral vibration with respect to the traveling direction of the body. In addition, the shock absorber D can also be used for installation objects other than railway vehicles.

[0019] In the description of the shock absorber D of the present invention, Figure 1 the up-down direction is taken as the up-down direction of the shock absorber D, Figure 1 the left-right direction in [[ ]] is taken as the left-right direction of the shock absorber D, Figure 1 and the direction passing through the paper surface in [[ ]] is taken as the lateral direction of the shock absorber D.

[0020] Next, each part will be described in detail. As Figure 1 shown, the cylinder 1 is cylindrical and includes: a ring-shaped head side flange 1a that radially protrudes outward from the left end outer periphery in [[ ]], from Figure 1 the left end outer periphery in [[ ]] to the outside in the radial direction, and a ring-shaped bottom side flange 1b that radially protrudes outward from Figure 1A circumferential bottom flange 1b that radially protrudes outward in the circumferential direction on the right end of the middle part, a circumferential convex part 1c that radially protrudes outward on the outer circumference between the head flange 1a and the bottom flange 1b, an elongation-side concave part 1d formed by a circumferential concave part between the head flange 1a and the convex part 1c on the outer circumference, a compression-side concave part 1e formed by a circumferential concave part between the bottom flange 1b and the convex part 1c on the outer circumference, a through hole 1f provided near the head flange 1a and communicating the inside of the cylinder 1 with the elongation-side concave part 1d, a through hole 1g provided near the bottom flange 1b and communicating the inside of the cylinder 1 with the compression-side concave part 1e, and two circumferential grooves 1h, 1i formed on the outer circumference of the convex part 1c in the circumferential direction. For example, the cylinder 1 is made of a thick-walled pipe as the base material, and the elongation-side concave part 1d, the compression-side concave part 1e, and the circumferential grooves 1h, 1i are formed on the outer circumference of the pipe through processing such as cutting and polishing. In this way, if the elongation-side concave part 1d, the compression-side concave part 1e, and the circumferential grooves 1h, 1i are formed on the outer circumference of the pipe, the head flange 1a, the bottom flange 1b, and the convex part 1c can be formed on the outer circumference of the cylinder 1.

[0021] Sealing rings 20 and 21 are respectively accommodated in the circumferential grooves 1h and 1i formed on the convex part 1c of the cylinder 1. In addition, Figure 1 the right end of the cylinder 1 is closed by a valve housing 9 fitted to the inner circumference of the right end. In addition, Figure 1 a ring-shaped guide member 10 is installed on the left end of the cylinder 1.

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

[0023] Furthermore, as Figure 2 and Figure 3As shown, the first cylinder 5 has a ring-shaped first boss portion 5a welded to its outer periphery. Inside the first boss portion 5a, it communicates with the inner peripheral side of the first cylinder 5 through a hole 5c penetrating the cylinder wall of the first cylinder 5. 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 extension side passage EP between the first cylinder 5 and the cylinder 1. Also, 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 formed by 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 in the present embodiment, a flat surface 5b is provided on a part in the circumferential direction as Figure 2 shown. 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 an extension side passage 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 of the cylinder 1. Therefore, although the installation 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, improving the degree of freedom of the installation position of the first boss portion 5a.

[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 to the outer periphery of the bottom flange 1b of the cylinder 1 and the outer periphery of the convex portion 1c. Figure 1 In the present embodiment, the left end of the second cylinder 6 is disposed at the axial center of the convex portion 1c of the cylinder 1, Figure 1 in the present embodiment, the right end of the second cylinder 6 is disposed beyond Figure 1To the right of the right end of the middle cylinder 1. The inner circumference of the second cylinder 6 faces the outer circumference of the bottom flange 1b of the cylinder 1 and 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 one sealing ring that is in close contact with both the inner circumference of the first cylinder 5 and the inner circumference of the second cylinder 6 and seals between the elongation-side passage EP and the compression-side passage CP is accommodated in this annular groove. In this way, although the elongation-side passage EP and the compression-side passage CP are separated by the convex portion 1c, 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 circumference of the first cylinder 5 and the outer circumference of the second cylinder 6.

[0025] Furthermore, as Figure 2 and Figure 3 shown, the second cylinder 6 has a ring-shaped second boss portion 6a welded to its outer circumference. 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 composed of 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 in setting the 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 and 6d are butted against each other. Moreover, when the first cylinder 5 and the second cylinder 6 are rotated and arranged with the flat surfaces 5b and 6b formed on the outer peripheries of the end portions 5d and 6d of the first cylinder 5 and the second cylinder 6 as marks so that the flat surfaces 5b and 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 and 6d of the first cylinder 5 and the second cylinder 6 are butted against each other so that the flat surfaces 5b and 6b face each other, the flat surfaces 5b and 6b form a flush plane. Moreover, a permanent magnet 40 is mounted on the flush plane formed by the flat surfaces 5b and 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 mounted on the first cylinder 5 and the second cylinder 6 by adhesion. Thus, since the marks for circumferential alignment of the first cylinder 5 and the second cylinder 6 can be used as the flat surfaces 5b and 6b, when the first cylinder 5 and the second cylinder 6 are butted for circumferential alignment, a flush plane for setting the permanent magnet 40 is formed by the flat surfaces 5b and 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 and 6b are arranged below the liquid reservoir T, and the permanent magnet 40 is also arranged below the liquid reservoir T. Therefore, when assembling the shock absorber D, the permanent magnet 40 is arranged below the liquid reservoir T where pollutants in the accumulated liquid are present, and thus it is easier to capture pollutants.

[0028] The outer cylinder 4 is disposed on the outer peripheral side of the first cylinder 5 and the second cylinder 6, covering the first cylinder 5 and the second cylinder 6, and accommodating the cylinder 1, the first cylinder 5, and the second cylinder 6 therein. In addition, a liquid storage tank T for storing liquid is formed in the annular gap between the outer cylinder 4 and the first cylinder 5 and the second cylinder 6. And, in addition to the liquid, the liquid storage tank T is also filled with gas. And the liquid, for example, can be hydraulic oil, but can also be a liquid other than hydraulic oil, and the gas, for example, can be an inert gas such as nitrogen, but in addition to the inert gas, it can also be air.

[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 damping valve EV is disposed on the radially outer side of the first hole 4a of the outer cylinder 4, and a compression side damping 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 damping valve EV and the compression side damping 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, flat surfaces 5b, 6b, which are 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 flat surfaces 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, then 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 3 shown, the first base 23 is a seat for mounting the extension side damping valve EV on the shock absorber D. The inner side surface opposite to the outer cylinder 4 bends 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 is provided with 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 3As 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 guide member 10 is fitted on the inner periphery of the left end in the [cylinder 1, the first cylinder 5, and the outer cylinder 4]. Figure 1 The guide member 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, 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, and is closed by the bottom cover 16.

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

[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 at the left end in the [description]; a large diameter portion 9b connected to the right of the small diameter portion 9a in the [description] and fitted on the inner periphery of the second cylinder 6; a flange 9c provided on the outer periphery of the large diameter portion 9b and abutting against the right end of the second cylinder 6 in the [description]; a recess 9d opening at the left end of the small diameter portion 9a in the [description]; and a plurality of ports 9e opening at the right end of the large diameter portion 9b in the [description] and communicating with the recess 9d. The ports 9e are arranged in a circumferential circle along the circumference of the recess 9d. Figure 1 Figure 1 Figure 1 Figure 1 Figure 1

[0036] In addition, the concave portion 9d of the valve housing 9 accommodates a compression side check valve 15, which has an annular valve body 15a that can open or close the outlet end of the port 9e, that is, Figure 1 annular retaining ring 15b, mounted on the side of the opening side of the recess 9d of the valve housing 9; a coil spring 15c, clamped between the valve body 15a and the retaining ring 15b, the valve body 15a is forced toward the bottom side of the recess 9d.

[0037] The bottom cover 16 is mounted on the outer tube 4 by welding. Figure 1 As shown in the right end, the outer tube 4 is closed Figure 1 The right end shown in FIG. 1 is provided with a large diameter portion 9b of the valve housing 9. Figure 1 The recess 16a is engaged with the right end, and the channel 16b that connects the recess 16a with the liquid storage tank T. In addition, Figure 1 The right end is provided with a bracket 16c, which can be mounted on a mounting portion provided on the body of the railway vehicle (not shown). 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 is connected to the liquid storage tank T through the recess 16a and the channel 16b, and the outlet end of the port 9e is connected to the compression side chamber R2. Therefore, the compression side suction channel CS is formed by the port 9e, the recess 16a and the channel 16b.

[0039] The compression side check valve 15 compresses the coil spring 15c through the valve body 15a to make it move in the concave portion 9d. Figure 1 9e is opened by moving to the left of the compression side chamber 15, thereby opening the port 9e to allow the liquid to flow from the liquid storage tank T to the compression side chamber R2. On the contrary, for the flow of the liquid flowing from the compression side chamber R2 to the liquid storage tank T, the compression side check valve 15 pushes the valve body 15a to the bottom of the recessed portion 9d by the pressure of the compression side chamber R2 and the force of the coil spring 15c, and closes the port 9e to close the valve, thereby preventing the above-mentioned liquid from moving from the compression side chamber R2 to the liquid storage tank T. The compression side check valve 15 opens a plurality of ports 9e arranged side by side on the same circumference, so even if the flow rate of the liquid flowing from the liquid storage tank T to the compression side chamber R2 is large, the liquid can flow from the liquid storage tank T to the compression side chamber R2 without encountering too much resistance. In this way, the compression side check valve 15 is arranged on the compression side suction channel CS, and the compression side suction channel CS 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 liquid from flowing in the opposite direction.

[0040] Next, the guide 10 is annular, such as Figure 1 as well as Figure 3As shown, it includes: an outer cylinder fitting portion 10a that fits into the inner circumference of the outer cylinder 4; a collar fitting portion 10b with a ring-shaped collar 14 fitted on its outer circumference, connected to the right side of the outer cylinder fitting portion 10a in Figure 1 and having an outer diameter smaller than that of the outer cylinder fitting portion 10a; a first cylinder fitting portion 10c with a first cylinder 5 fitted on its outer circumference, connected to the right side of the collar fitting portion 10b in Figure 1 and having an outer diameter smaller than that of the collar fitting portion 10b; a cylinder fitting portion 10d with a cylinder 1 fitted on its outer circumference, connected to the right side of the first cylinder fitting portion 10c in Figure 1 and having an outer diameter smaller than that of the first cylinder fitting portion 10c; a ring-shaped valve mounting portion 10e protruding from the inner circumference at the right end of the cylinder fitting portion 10d; eight ports 10f opening at the right end of the cylinder fitting portion 10d and on the outer circumference of the valve mounting portion 10e and communicating with the outer circumference of the collar fitting portion 10b; and a return passage 10g opening at the right end of the outer cylinder fitting portion 10a and leading to the left end. And, the eight ports 10f open at equal intervals on the same circumference around the rod 2 at the right end of the cylinder fitting portion 10d in Figure 1 and extend radially and open at equal intervals at the bottom of a ring-shaped groove 10b1 provided on the outer circumference of the collar fitting portion 10b in the circumferential direction. Since the ring-shaped groove 10b1 is provided on the entire outer circumference of the collar fitting portion 10b, it communicates with all of the eight ports 10f. Figure 1 A cylindrical bushing 11 is installed on the inner circumference of the guide member 10, which is in sliding contact with the outer circumference of the rod 2 and guides the axial movement of the rod 2, thereby ensuring the smooth movement of the rod 2. A sealing ring 12 that closely adheres to the outer circumference of the rod 2 is also installed. Figure 1 The collar 14 is ring-shaped, with an outer diameter smaller than the inner diameter of the outer cylinder 4, and has a notch 14a provided on a part of its outer circumference, a passage 14b opening from the end face of the notch 14a and communicating with the inner circumference, and a pin insertion groove 14c provided on the outer circumference at a position opposite to the notch 14a in the circumferential direction, and is fitted on the outer circumference of the collar fitting portion 10b of the guide member 10.

[0041]

[0042]

[0043] ​​When the collar 14 is press-fitted onto the outer periphery of the collar fitting portion 10b of the guide member 10, it can be fixed to the outer periphery of the collar fitting portion 10b, and the respective channels 14b of the collar 14 are respectively opposed to the annular grooves 10b1. All of the respective channels 14b and all of the respective ports 10f communicate with each other through the annular groove 10b1. Further, in the shock absorber D of the present embodiment, the annular groove 10b1 that forms an annular passage communicating the port 10f and the channel 14b is provided on the outer periphery of the collar fitting portion 10b of the guide member 10. Instead of providing it on the outer periphery of the collar fitting portion 10b, an annular groove that forms an annular passage communicating the port 10f and the channel 14b may be provided on the inner periphery of the collar 14.

[0044] Moreover, when the guide member 10 with the collar 14 fitted on its outer periphery, the cylinder fitting portion 10d is fitted into the cylinder 1, the first cylinder fitting portion 10c is fitted into the first cylinder 5, and the outer cylinder fitting portion 10a is fitted into the outer cylinder 4, Figure 1 the left end of the intermediate cylinder 1 abuts against Figure 1 the right end of the first cylinder fitting portion 10c, Figure 1 the left end of the first cylinder 5 abuts against Figure 1 the right end of the collar fitting portion 10b. Further, 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 guide member 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 is fixed to the collar fitting portion 10b.

[0045] In addition, if the guide member 10 is fitted to the left ends of the cylinder 1, the first cylinder 5, and the outer cylinder 4 Figure 1 as shown, the channel 14b in which 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 guide member 10 communicates with the liquid storage tank T through the channel 14b, and the outlet end of the port 10f communicates with the inside of the extension side chamber R1 in the cylinder 1. In this way, the extension side suction channel ES is formed by the port 10f, the annular groove 10b1, and the channel 14b.

[0046] Further, the channel 14b opens at the cutout 14a provided on the outer periphery of the collar 14, and the cross-sectional area of the gap between the cutout 14a and the outer cylinder 4 is made larger than the total cross-sectional area of all the channels 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 surface of the cutout 14a and the outer cylinder 4, this gap does not create an excessive resistance to the flow of the liquid. In addition, as Figure 1As 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 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 in the upper part of the liquid storage tank T is filled with gas, and the cutout 14a forming the inlet end of the passage 14b always faces downward of the shock absorber D and faces the liquid, so care should be taken that the inlet end of the passage 14b does not face the gas. Also, care should be taken that the return passage 10g provided on the guide member 10, whose opening faces the pin insertion groove 14c of the collar 14, is not blocked when the collar 14 is engaged with the collar engaging portion 10b.

[0047] In addition, in the present embodiment, the collar 14 is fitted on the outer circumference of the collar engaging portion 10b of the guide member 10. By pressing the collar 14 onto the outer circumference of the guide member 10, the space between the collar 14 and the guide member 10 is sealed. A sealing member can also be provided between the collar 14 and the guide member 10 to prevent the port 10f from communicating with the liquid storage tank T without passing through the passage 14b.

[0048] Furthermore, an extension-side check valve 13 is mounted on the outer circumference of the valve mounting portion 10e of the guide member 10. The extension-side check valve includes: a valve body 13a formed of an annular plate, which can Figure 1 be seated on the right end of the cylinder engaging portion 10d to open or close the opening end of the port 10f; a spring seat 13b having an L-shaped cross section, which is fitted on the outer circumference of the valve mounting portion 10e and is axially opposed to the valve body 13a; a conical spiral spring 13c, which is clamped between the valve body 13a and the spring seat 13b as a spring and applies a force to the valve body 13a toward the right end of the cylinder engaging portion 10d; and a snap ring 13d, which is mounted on the annular groove 10e1 provided on the outer circumference of the front end ( Figure 1 the right end in the figure) of the valve mounting portion 10e to prevent the spring seat 13b from coming off the valve mounting portion 10e. The valve body 13a makes the inner circumference slide in contact with the outer circumference of the valve mounting portion 10e, and can displace the outer circumference of the valve mounting portion 10e axially ( Figure 1 the left-right direction shown in the figure). When it moves away from Figure 1 the right end of the cylinder engaging portion 10d, it opens the port 10f, and when it abuts against Figure 1 the right end of the cylinder engaging portion 10d, it cuts off the port 10f.

[0049] The above-mentioned extension-side check valve 13 is provided on the extension-side suction passage ES composed of the port 10f, the annular groove 10b1, and the passage 14b, and opens or closes the port 10f. Moreover, for the flow of the liquid from the liquid storage tank T to the extension-side chamber R1 through the port 10f, the extension-side check valve 13 compresses the helical spring 13c by the valve body 13a to move the outer periphery of the valve mounting portion 10e of the guide member 10 toward the front end side (i.e., Figure 1 the middle right) to open the valve, so opening the 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 from the extension-side chamber R1 to the liquid storage tank T, the extension-side check valve 13 presses the valve body 13a toward the Figure 1 middle right end of the cylinder fitting portion 10d by the pressure of the extension-side chamber R1 and the acting force of the helical spring 13c to close the port 10f and close the valve, thereby preventing the liquid flowing from the extension-side chamber R1 to the liquid storage tank T from flowing. As described above, the extension-side check valve 13 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 liquid from flowing in the reverse direction.

[0050] Since the extension-side check valve 13 can open a plurality of ports 10f arranged on the same circumference around the rod 2 of the guide member 10, even if the liquid flow rate from the liquid storage tank T to the extension-side chamber R1 is large, the liquid can be allowed to flow from the liquid storage tank T to the extension-side chamber R1 without imposing too much resistance on it. Thus, when setting the extension-side suction passage ES connecting the extension-side chamber R1 and the liquid storage tank T, since the guide member 10 inserted in the center and fitted on 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. And the spring of the extension-side check valve 13 can also be a spring other than the helical spring 13c. And the number of ports 10f provided is appropriately set so that in the actual environment of using the shock absorber D, when the liquid of 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.

[0051] A collar 14 is fitted on the outer periphery of the guide member 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 of the cylinder 1 having the first cylinder 5 and the second cylinder 6 fitted on its outer periphery. At this time, the outer periphery of the first cylinder fitting portion 10c of the guide member 10 is fitted with the Figure 1 inner periphery of the left end of the first cylinder 5. In addition, the cylinder 1 having the first cylinder 5 and the second cylinder 6 fitted on its outer periphery and the second cylinder 6 Figure 1The inner circumference of the middle right end is fitted with a valve housing 9 with a compression side check valve 15 installed. The cylinder 1, the first tube 5, the second tube 6, the valve housing 9 and the guide 10 assembled in this way are inserted into the Figure 1 After the outer tube 4 with the bottom cover 16 installed on the middle right end, it is threadedly connected to the outer tube 4. Figure 1 The sealing housing 17 and the bottom cover 16 on the inner circumference of the left end are clamped and fixed in the outer tube 4. In addition, the sealing housing 17 is annular and has: a threaded portion 17a, which is formed on the outer circumference with the outer tube 4. Figure 1 The threaded portion 4c on the inner circumference of the left end is threadedly connected; the sealing ring 17b and the dustproof sealing ring 17c are accommodated in the inner circumference provided at Figure 1 The annular recesses at the left and right ends of the rod 2 are in sliding contact with the outer periphery of the rod 2. Therefore, when the seal housing 17 is threadedly coupled to the outer tube 4 and tightened, the cylinder 1, the first tube 5, the second tube 6, the valve housing 9 and the guide 10 are fixed in the outer tube 4 by applying axial force through the seal housing 17 and the bottom cover 16. As described above, the outer periphery of the rod 2 is sealed by the seal ring 17b, and the liquid attached to the outer periphery of the rod 2 and passing over the seal ring 12 installed on the guide 10 is scraped by the seal ring 17b and returned to the liquid storage tank T through the return channel 10g of the guide 10.

[0052] In the above case, the collar 14 opens the channel 14b at the cutout 14a to suck the liquid from the liquid storage tank T and supply it to the extension side chamber R1. However, the same may be applied as follows: Figure 4 As shown in the figure, the suction pipe 142 is installed on the collar 141.

[0053] like Figure 4 As shown, the shaft ring 141 is annular, and its outer diameter is smaller than the inner diameter of the outer tube 4, and the inner diameter on the liquid storage tank side is smaller, and the inner circumference is provided with a large inner diameter portion 141a and a small inner diameter portion 141b, and further provided with a recessed portion 141c opening radially from a part of the inner circumference on the circumference of the large inner diameter portion 141a, five insertion holes 141d opening from the liquid storage tank side and communicating with the recessed portion 141c, a pin through hole 141e opening at the end opposite to the liquid storage tank side, and a pin through hole 141e provided on the outer circumference and Figure 4 The pin insertion groove 141f at the middle upper end is fitted on the outer periphery of the collar fitting portion 10b of the guide member 10. The suction pipe 142 whose front end is arranged near the center of the liquid storage tank T is respectively installed on the insertion hole 141d of the collar 141.

[0054] like Figure 4As shown, the guide member 10 fitted with the collar 141 matches the inner peripheral shape of the collar 141. The collar fitting portion 10b has a large-diameter portion 10b2 that fits with the large-diameter portion 141a of the collar 141 and a small-diameter portion 10b3 that fits with the small-diameter portion 141b. In addition to having annular grooves 10b4 and 10b5 for accommodating the sealing rings 143 and 144 on the outer peripheries of the large-diameter portion 10b2 and the small-diameter portion 10b3 respectively, it also has the same structure as the Figure 1 guide member 10 shown.

[0055] The axial length of the collar 141 is equal to the axial length of the collar fitting portion 10b of the guide member 10. The axial length of the large-diameter portion 141a is greater than the axial length of the large-diameter portion 10b2, and the axial length of the small-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 guide member 10, the pin 19 mounted on the guide member 10 is inserted into the pin through-hole 141e and the collar 141 is prevented from rotating. Moreover, the large-diameter portion 141a of the collar 141 fits with the large-diameter portion 10b2 of the collar fitting portion 10b and is in close contact with the sealing ring 143, the small-diameter portion 141b of the collar 141 fits 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 recess 141c formed on the inner periphery of the collar 141 and is internally communicated with the liquid storage tank T via the suction pipe 142. In addition, since the annular passage G is formed to surround the collar fitting portion 10b, it opens at a position around the rod member 2 of the guide member 10 and extends radially, and can communicate with the recess 141c of the collar 141 and the suction pipe 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 connecting the port 10f and the passage 14b can also be provided by configuring the inner peripheral shape of the collar 141 and the outer peripheral shape of the collar fitting portion 10b of the guide member 10 as described above.

[0056] Thus, in the guide member 10 fitted with the Figure 4 collar 141 shown, an elongated-side suction passage ES is formed by the suction pipe 142, the recess 141c, the annular passage G, and the port 10f. Similar to the Figure 1 shock absorber D shown, an elongated-side check valve 13 is provided on the elongated-side suction passage ES. Therefore, if the liquid in the elongated-side chamber R1 is insufficient, the elongated-side check valve 13 opens, and liquid is supplied from the liquid storage tank T to the elongated-side chamber R1 through the elongated-side suction passage ES.

[0057] In addition, when the guide member 10 fitted with the collar 141 is fitted onto the cylinder 1, the first cylinder 5, and the outer cylinder 4, the collar 141 is in contact withFigure 1 Similar to the collar 14 shown, the rotation in the circumferential direction with respect to the outer cylinder 4 is stopped and positioned by inserting the pin 18 through the outer cylinder 4 into the pin insertion groove 141f. The suction pipe 142 is disposed 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 disposed near the center of the liquid storage tank T. Even when the vibration generated during the expansion and contraction of the horizontally mounted shock absorber D causes the liquid level in the liquid storage tank T to fluctuate, the front end of the suction pipe 142 can always be present in the liquid, preventing gas from entering the extension side chamber R1.

[0058] Next, the extension side damping valve EV is mounted on the first base 23 by 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 by the joint 33, where the second base is mounted on the outer cylinder 4.

[0059] The joint 31 includes: a rectangular bottom plate 31a that abuts against the valve mounting surface 23a on the side opposite to the outer cylinder of the first base 23; 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 face 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, the joint 31 is bolted to the first base 23 by combining the bolts (not shown) inserted through the through holes with the screw holes of the first base 23.

[0060] One end of the extension side pipe 32 is fitted into the portion with a larger inner diameter of the stepped hole 31b of the joint 31. 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 formed by 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.

[0061] The joint member 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 face 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 member 33 configured in this way has through holes at its 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 bolts (not shown) inserted into the through holes with the screw holes of the second base 24.

[0062] One end of the compression side pipe 34 is fitted into the portion of the stepped hole 33b of the joint member 33 with a larger inner diameter. The other end of the compression side pipe 34 is fitted into the second boss portion 6a of the second cylinder 6. Therefore, through the compression side pipe 34, the compression side passage CP between the cylinder 1 and the second cylinder 6 and the inside of the stepped hole 33b are communicated. And the compression side pipe 34 is clamped by the stepped portion of the stepped hole 33b and the stepped portion of the continuous hole composed of the second boss portion 6a and the hole 6c of the second cylinder 6, and is fixed to the joint member 33 and the second cylinder 6.

[0063] In the present embodiment, the extension side damper valve EV includes a valve housing 60 held on the first base 23 by the joint member 31, a variable overflow valve 61 provided inside the valve housing 60, and a solenoid 62 for adjusting the opening pressure of the variable overflow valve 61.

[0064] The valve housing 60 is fixed to the joint member 31 by bolts (not shown) in a state of abutting against the side surface of the bottom plate 31a of the joint member 31 opposite to the first base. Therefore, the valve housing 60 is fixed to the first base 23 through the joint member 31. Moreover, the valve housing 60 has a flow passage 60a with one end communicating with the inside of the stepped hole 31b of the joint member 31 and the other end communicating with the inclined hole 31c. The variable overflow valve 61 is provided inside the valve housing 60 and in the middle of the flow passage 60a. And in the present embodiment, the extension side damper valve EV is connected to the first base 23 via the joint member 31. For example, the bottom plate 31a of the joint member 31 can be omitted, and a structure in which the extension side pipe 32 is held on the valve housing 60 can be adopted to directly hold the extension side damper valve EV on the first base 23. It is also possible to adopt a structure in which the joint member 31 and the valve housing 60 are integrally formed and inseparable.

[0065] The variable overflow valve 61 includes a valve body 61a that opens or closes the flow path 60a, a spring 61b that biases the valve body 61a in the direction of blocking the flow path 60a, and a pilot passage 61c that applies pressure in the direction of opening the flow path 60a. The flow path 60a communicates 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 communicates with the liquid storage tank T through the inclined hole 31c and inside the first hole 4a and outside the extension side pipe 32 (between the inner circumference of the first hole 4a and the outer circumference of the extension side pipe 32). Moreover, the pilot passage 61c of the variable overflow valve 61 acts on the valve body 61a with the pressure of the extension side chamber R1 in the valve opening direction.

[0066] The solenoid 62 is mounted on Figure 3 the left end of the valve housing 60 shown. Although not shown in detail, it includes a plunger 62a, a coil that drives 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 of protruding from the frame 62b, and applies a thrust force against the spring 61b to the valve body 61a of the variable overflow 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.

[0067] 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 is possible to adjust the magnitude of the valve opening pressure of the variable overflow valve 61. In the present embodiment, if the amount of electric current supplied to the solenoid 62 is set to the maximum, the variable overflow valve 61 sets the valve opening pressure to the minimum, and if no power is supplied to the solenoid 62, the variable overflow valve 61 sets the valve opening pressure to the maximum. Therefore, the variable overflow valve 61 can control the pressure in the upstream extension side chamber R1 communicated with by the extension side passage EP by the amount of electric current supplied to the solenoid 62.

[0068] In the present embodiment, the compression side damping valve CV includes a valve housing 63 held on the second base 24 by a joint 33, a variable overflow valve 64 provided inside the valve housing 63, and a solenoid 65 that adjusts the valve opening pressure of the variable overflow valve 64.

[0069] 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. Thus, the valve housing 63 is fixed to the second base 24 by the joint member 33. Further, the valve housing 63 has a flow passage 63a with one end communicating with the inside of the stepped hole 33b of the joint member 33 and the other end communicating with the inclined hole 33c, and a variable overflow valve 64 is provided inside the valve housing 63 and in the middle of the flow passage 63a. In the present embodiment, the compression side damper valve CV is connected to the second base 24 through the joint member 33. For example, the bottom plate 33a of the joint member 33 may be omitted, and a structure in which the compression side pipe 34 is held by the valve housing 63 may be adopted to directly hold the compression side damper 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 may be adopted.

[0070] The variable overflow valve 64 includes a valve body 64a that opens or closes the flow passage 63a, a spring 64b that biases the valve body 64a in the direction of blocking the flow passage 63a, and a pilot passage 64c that applies pressure in the direction of opening the flow passage 63a. The flow passage 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 reservoir tank T through the inclined hole 33c and the second hole 4b and outside the compression side pipe 34 (between the inner circumference of the second hole 4b and the outer circumference of the compression side pipe 34). Further, 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.

[0071] The solenoid 65 is mounted on Figure 3 the left end of the shown valve housing 63. 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. When energized, the solenoid 65 drives the plunger 65a in the direction of protruding from the frame 65b, and applies a thrust force against the spring 64b to the valve body 64a of the variable overflow valve 64, thereby pressing 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. Further, the solenoid 65 does not apply a thrust force to the valve body 64a in a non-energized state.

[0072] Therefore, the solenoid 65 can adjust the magnitude of the thrust applied to the valve body 64a according to the amount of electricity conducted, so that the opening pressure of the variable relief valve 64 can be adjusted. In the present embodiment, if the amount of electric current supplied to the solenoid 65 is set to the maximum, the variable relief valve 64 sets the opening pressure to the minimum, and if no power is supplied to the solenoid 65, the variable relief valve 64 sets the opening pressure to the maximum. Therefore, the variable relief valve 64 can control the pressure in the upstream compression-side chamber R2 communicated by the compression-side passage CP by the amount of electricity conducted to the solenoid 65.

[0073] The shock absorber D is configured as described above, and the operation of the shock absorber D will be described below. First, the operation when the shock absorber D extends will be described. When the shock absorber D extends, the piston 3 moves leftward in the cylinder 1, Figure 1 so that the extension-side chamber R1 shrinks, and the compression-side chamber R2 expands. Since the shrinking extension-side chamber R1 communicates with the reservoir tank T through the extension-side passage EP and the extension-side damping valve EV, the liquid in the extension-side chamber R1 is discharged to the reservoir tank T through the extension-side passage EP and the extension-side damping valve EV. Since the variable relief valve 61 can apply resistance to such liquid movement, the pressure in the extension-side chamber R1 is adjusted to be greater than the pressure in the reservoir tank T and equal to the opening pressure of the variable relief valve 61. In addition, the compression-side chamber R2, whose volume has increased 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 reservoir tank T through the compression-side intake passage CS by opening the compression-side check valve 15. Therefore, the pressure in the compression-side chamber R2 is approximately equal to the pressure in the reservoir tank T.

[0074] When the shock absorber D extends in this way, the pressure of the extension-side chamber R1 acting on the side of the extension-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 extension-side damping force that hinders its own extension operation. In addition, since the opening pressure of the variable relief valve 61 can be adjusted in magnitude according to the amount of electric current supplied to the solenoid 62, the magnitude of the extension-side damping force generated when the shock absorber D extends can be adjusted by the extension-side damping valve EV.

[0075] Next, the operation when the shock absorber D contracts will be described. When the shock absorber D contracts, the piston 3 moves rightward in the cylinder 1, Figure 1moves to the right in the figure, so the compression side chamber R2 shrinks, and the extension side chamber R1 expands. Since the shrunk compression side chamber R2 is connected to the liquid storage tank T through the compression side channel 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 channel CP and the compression side damping valve CV. Since resistance can be applied to the movement of such liquid 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, since the liquid is lacking in the extension side chamber R1 whose volume expands due to the movement of the piston 3, the insufficient part of the liquid can be supplied to the extension side chamber R1 from the liquid storage tank T via the extension side suction channel ES by opening the extension side check valve 13. Therefore, the pressure of the extension side chamber R1 is approximately equal to the pressure of the liquid storage tank T.

[0076] When the shock absorber D contracts in this way, the pressure of the compression side chamber R2 acting on the side of the compression side chamber of the piston 3 is greater than the pressure of the extension side chamber R1 acting on the side of the extension side chamber of the piston 3, and 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 through the compression side damping valve CV.

[0077] When the shock absorber D extends, since resistance is applied to the flow of the liquid flowing from the extension side chamber R1 toward the liquid storage tank T by the extension side damping valve EV, and only the liquid in the extension side chamber R1 is compressed to generate the extension side damping force, sufficient damping force can be generated even when the liquid column compression rigidity becomes large and the extension work is performed at an extremely low speed, without causing insufficient damping force. In addition, when the shock absorber D contracts, since resistance is applied to the flow of the liquid flowing from the compression side chamber R2 toward the liquid storage tank T by the compression side damping valve CV, and only the liquid in the compression side chamber R2 is compressed to generate the compression side damping force, sufficient damping force can be generated even when the contraction work is performed at an extremely low speed, without causing insufficient damping force.

[0078] In addition, the shock absorber D generates the extension side damping force by using the extension side damping valve EV and generates the compression side damping force by using the compression side damping valve CV, so 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 the 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, and the compression side damping force generated when the shock absorber D contracts can be increased.

[0079] Also, as described above, when the shock absorber D performs a contraction operation, liquid is supplied from the liquid reservoir 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 in order to increase the compression-side damping force of the shock absorber D, the amount of liquid supplied from the liquid reservoir T to the extension-side chamber R1 should be increased when the shock absorber D contracts.

[0080] In contrast, 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 guide member 10 by using the annular valve body 13a disposed on the outer periphery of the rod 2, the extension-side suction passage ES having a sufficiently ensured flow path area can be formed with respect to the small guide member 10.

[0081] Therefore, even when the shock absorber D having a reduced cross-sectional area of the rod 2 and an increased inner diameter of the cylinder 1 in order to increase the compression-side damping force when the shock absorber D contracts in the extremely low speed range contracts at a high speed, the extension-side suction passage ES having a sufficiently large flow path area can be formed on the guide member 10. Therefore, poor liquid supply does not occur in the extension-side chamber R1.

[0082] 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 extension-side chamber R1 and a compression-side chamber R2; a first cylinder 5 that is disposed on the outer peripheral side of the cylinder 1 and forms an extension-side passage EP communicating with the extension-side chamber R1 between the first cylinder 5 and the cylinder 1; a second cylinder 6 that is disposed on the outer peripheral side of the cylinder 1 and forms a compression-side passage CP communicating with the compression-side chamber R2 between the second cylinder 6 and the cylinder 1; an outer cylinder 4 that is disposed on the outer peripheral sides of the first cylinder 5 and the second cylinder 6 and forms a liquid reservoir T for storing liquid between the first cylinder 5 and the second cylinder 6; an extension-side suction passage ES that allows only the liquid flowing from the liquid reservoir T to the extension-side chamber R1 to flow; a compression-side suction passage CS that allows only the liquid flowing from the liquid reservoir T to the compression-side chamber R2 to flow; an extension-side damping valve EV that applies resistance to the flow of the liquid flowing from the extension-side chamber R1 to the liquid reservoir T through the extension-side passage EP; and a compression-side damping valve CV that applies resistance to the flow of the liquid flowing from the compression-side chamber R2 to the liquid reservoir T through the compression-side passage CP.

[0083] When the shock absorber D configured in this way performs an extension operation, since resistance is applied to the flow of the liquid from the extension-side chamber R1 toward the reservoir tank T through the extension-side damping valve EV, 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. In addition, in the shock absorber D of the present embodiment, when performing an extension operation, resistance is applied to the flow of the liquid from the extension-side chamber R1 toward the reservoir tank T through the extension-side damping valve EV, and only the liquid in the extension-side chamber R1 is compressed to generate an extension-side damping force. When performing a contraction operation, resistance is applied to the flow of the liquid from the compression-side chamber R2 to the reservoir tank T by using the compression-side damping valve CV, and only the liquid in the compression-side chamber R2 is compressed to generate a compression-side damping force. Since the outer diameter of the rod 2 and the inner diameter of the cylinder 1 are not restricted like those of a conventional shock absorber, as long as there are no strength problems, the outer diameter of the rod 2 can be reduced while increasing the inner diameter of the cylinder 1.

[0084] In summary, when the shock absorber D according to the present embodiment performs an extension operation, while improving the liquid column compression rigidity, the outer diameter of the rod 2 can be reduced. Therefore, even when extending at an extremely low speed, sufficient damping force can be generated. In addition, the shock absorber D according to the present embodiment can increase the inner diameter of the cylinder 1, and the damping force during contraction at an extremely low speed can be improved. In addition, 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 be relatively rotated in the circumferential direction before being fixed. Therefore, two passages, i.e., 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 tank 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. Therefore, the outlet of the extension-side passage EP and the extension-side damping valve EV can be arranged very close to each other to shorten the length of the pipeline connecting the two, and the outlet of the compression-side passage CP and the compression-side damping valve CV can be arranged very close to each other to shorten 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).

[0085] Thus, 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 in the circumferential direction before being fixed, even if the installation positions of the extension-side damping valve EV and the compression-side damping 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 damping 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 damping valve CV can also be arranged very close to each other. In summary, even if the installation positions of the extension-side damping valve EV and the compression-side damping 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 tank T through this pipeline can also be reduced, and in order to ensure the volume of the reservoir tank T, the diameter of the outer cylinder 4 will not become significantly thicker. Therefore, in the shock absorber D according to the present embodiment, it is easy to change the installation positions of the extension-side damping valve EV and the compression-side damping valve CV on the outer cylinder 4 according to the equipment, and it will not cause an increase in the size of the shock absorber D. Therefore, the mounting performance and practicality on the equipment can be improved.

[0086] Furthermore, in the shock absorber D according to the present embodiment, since the first cylinder 5 and the second cylinder 6 can be fitted onto 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, 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 during the assembly of the shock absorber D. In addition, the first cylinder 5 and the second cylinder 6 can move the opposite ends 5d and 6d away from each other. In the shock absorber D of the present embodiment, by making the ends 5d and 6d abut against each other and being clamped by the guide member 10 and the valve housing 9, they can be fixed to the outer periphery of the cylinder 1 without play, which is advantageous. In addition, when the ends 5d and 6d are made to abut against each other and the first cylinder 5 and the second cylinder 6 are clamped by the guide member 10 and the valve housing 9, the first cylinder 5 and the second cylinder 6 may not be joined by welding or screw connection. Therefore, the installation performance can be improved while the processing cost can be reduced.

[0087] Further, in the shock absorber D of the present embodiment, the cylinder 1 includes an extension-side recess 1d provided on the outer periphery and forming an extension-side passage EP between the first cylinder 5, a compression-side recess 1e provided on the outer periphery and forming a compression-side passage CP between the second cylinder 6, and a convex portion 1c protruding 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 and provided 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 peripheries of the first cylinder 5 and the second cylinder 6 and then the extension-side passage EP and the compression-side passage CP are formed, the machining is easier and the machining cost can be reduced.

[0088] Moreover, in the shock absorber D of the present embodiment, a head-side flange 1a and a bottom-side flange 1b are provided at the end of the cylinder 1, but these head-side flange 1a and bottom-side flange 1b can also be omitted. However, since the cylinder 1 is provided with the head-side flange 1a and the bottom-side flange 1b, it has the advantage that looseness is not likely to occur between the cylinder 1 and the first cylinder 5 and the second cylinder 6.

[0089] Furthermore, in the shock absorber D of the present embodiment, the outer cylinder 4 includes a first hole 4a and a second hole 4b that communicate the inside and the outside. The first cylinder 5 has a first boss portion 5a on the outer periphery at a position opposite to the first hole 4a, and the inside of the first boss portion communicates with the extension-side passage EP. The second cylinder 6 has a second boss portion 6a on the outer periphery at a position opposite to the second hole 4b, and the inside of the second boss portion communicates with the compression-side passage CP. The extension-side damping 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 damping valve EV is communicated with the reservoir tank T outside the extension-side pipe 32 within the first hole 4a. The compression-side damping 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 damping valve CV is communicated with the reservoir tank T outside the compression-side pipe 34 within the second hole 4b.

[0090] According to the shock absorber D configured in this way, 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, the first boss portion 5a can be arranged at a position extremely close to the extension side damping valve EV, and the second boss portion 6a can be arranged at a position extremely close to the compression side damping valve CV, shortening the extension side pipe 32 and the compression side pipe 34 that reduce the volume in the reservoir T, and the first hole 4a and the second hole 4b can be used as channels to return the liquid passing through the extension side damping valve EV and the compression side damping valve CV to the reservoir T. Further, 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 first cylinder 5 and the second cylinder 6 over their entire lengths, and the volume in the reservoir 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.

[0091] In addition, further, in the shock absorber D of the present embodiment, the first cylinder 5 and the second cylinder 6 butt and abut their opposite end portions 5d, 6d against each other, and at the same time, flat surfaces 5b, 6b for circumferential alignment are provided on the outer peripheries of the opposite end portions 5d, 6d, and permanent magnets 40 are provided on the flat surfaces 5b, 6b. According to the shock absorber D configured in this way, since the permanent magnets 40 are provided on the flat surfaces 5b, 6b provided on the outer peripheries of the first cylinder 5 and the second cylinder 6, it is possible to capture contaminants such as cutting chips generated when processing the components constituting the shock absorber D in the liquid in the 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 installed on the flat surfaces 5b, 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 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, 6b, so that the first cylinder 5 and the second cylinder 6 can be arranged at appropriate positions without error.

[0092] Moreover, the shock absorber D of the present embodiment is annular and includes a guide member 10 that fits around the outer periphery of the cylinder 1 and has a rod 2 inserted through its inner periphery. The guide member 10 has an extension-side suction passage ES that allows only the liquid to flow from the liquid reservoir T to the extension-side chamber R1. The extension-side suction passage ES has a plurality of ports 10f that are arranged side by side around the rod 2 at the cylinder-side end of the cylinder fitting portion 10d of the guide member 10 that fits with the cylinder 1. Therefore, according to the shock absorber D of the present embodiment, an extension-side suction passage ES with a sufficient flow path area can be formed relative to the small guide member 10. Even when the shock absorber D contracts at high speed, insufficient suction of the liquid does not occur in the extension-side chamber R1, and a stable compression-side damping force can be generated.

[0093] In addition, the shock absorber D of the present embodiment includes an annular valve body 13a that is annular and can move axially relative to the cylinder-side end of the cylinder fitting portion 10d of the guide member 10 to open or close the outlet ends of the respective ports 10f, and a spring (conical helical spring) 13c that biases the valve body 13a toward the cylinder fitting portion 10d. In the shock absorber D configured in this way, if the valve body 13a moves away from the cylinder fitting portion 10d of the guide member 10, all the outlet ends of the ports 10f can be opened. Therefore, when the shock absorber D contracts, the liquid can be quickly supplied from the liquid reservoir T to the extension-side chamber R1, and there will be no shortage of liquid in the extension-side chamber R1.

[0094] Furthermore, the shock absorber D of the present embodiment includes a collar 14 that fits around the outer periphery of the guide member 10 and faces the liquid reservoir T. A cutout 14a facing the lower part of the liquid reservoir T, a passage 14b that opens from the cutout 14a and communicates with the inner periphery, and an annular passage that communicates the port 10f and the passage 14b can be provided on the collar 14. 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 guide member 10, only the liquid can be supplied to the extension-side chamber R1 while preventing gas from mixing in from below the liquid reservoir T. Therefore, it is most suitable for horizontal installation to suppress the horizontal lateral vibration of the body of a railway vehicle.

[0095] In addition, the shock absorber D of the present embodiment includes a collar 141 that fits around the outer periphery of the guide member 10 and faces the liquid reservoir T, and a plurality of suction pipes 142 that are mounted on the collar and have their front ends facing the center of the lower part of the liquid reservoir T. An annular passage that communicates with the inside of the suction pipes 142 and the port 10f is provided between the guide member 10 and the collar 141. According to the shock absorber D having such a structure, since the front ends of the suction pipes 142 are arranged near the center of the lower part inside the liquid reservoir T, the shock absorber D can supply only the liquid to the extension-side chamber R1 while preventing gas from mixing in from below the liquid reservoir T even when vibrating. Therefore, it is most suitable for horizontal installation to suppress the horizontal lateral vibration of the body of a railway vehicle.

[0096] Further, 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 it is not required to adjust the damping force of the shock absorber D, they may also be damping valves that cannot adjust the damping force.

[0097] The preferred embodiments of the present invention have been described in detail above. However, as long as the scope of the claims is not departed from, modifications, deformations, and changes can be made.

[0098] Symbol Explanation

[0099] 1 Cylinder

[0100] 1c Protrusion

[0101] 1d Extension-side recess

[0102] 1e Compression-side recess

[0103] 2 Rod

[0104] 3 Piston

[0105] 4 Outer cylinder

[0106] 4a First hole

[0107] 4b Second hole

[0108] 5 First cylinder

[0109] 5a First boss portion

[0110] 5b Plane

[0111] 5d End face

[0112] 6 Second cylinder

[0113] 6a Second boss portion

[0114] 6b Plane

[0115] 6d End face

[0116] 31 Extension-side pipe

[0117] 33 Compression-side pipe

[0118] 30 Permanent magnet

[0119] CP Compression-side passage

[0120] CS Compression-side suction passage

[0121] CV Compression-side damping valve

[0122] D Shock absorber

[0123] EP Elongation Side Passage

[0124] ES Elongation Side Suction Passage

[0125] EV Elongation Side Damper Valve

[0126] R1 Elongation Side Chamber

[0127] R2 Compression Side Chamber

[0128] 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 to divide the interior of the cylinder into an extension side chamber and a compression side chamber; 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 outer cylinder, which is arranged on the outer peripheral side of the first cylinder and the second cylinder, and forms a liquid storage tank for storing liquid between the outer cylinder and the first cylinder and the second cylinder; an elongated side suction passage that only allows liquid to flow from the liquid storage tank to the elongated side chamber; a compression side suction passage, which only allows liquid to flow from the liquid storage tank to the compression side chamber; an extension-side damping valve that applies resistance to the flow of liquid from the extension-side chamber to the liquid storage tank through the extension-side passage; A compression-side damping valve applies resistance to the flow of liquid from the compression-side chamber to the liquid storage tank through the compression-side passage.

2. The shock absorber according to claim 1, wherein: The cylinder has: An extension side recessed portion is arranged on the outer periphery and forms the extension side channel between the first tube, a compression side recessed portion is arranged on the outer periphery and forms the compression side channel between the second tube, and a convex portion protrudes radially outward from between the extension side recessed portion and the compression side recessed portion to separate the extension side recessed portion and the compression side recessed portion.

3. The shock absorber according to claim 1, wherein: The outer cylinder has a first hole and a second hole connecting the inside and the outside. The first tube has a first boss portion which is opposite to the first hole and whose inner periphery is connected to the elongated side channel. The second cylinder has a second boss portion which is opposite to the second hole and whose inner periphery is connected to the compression side passage. The extension-side damping valve disposed outside the outer tube is connected to the extension-side passage by inserting the extension-side tube in the first hole and the first boss portion, and the extension-side damping valve is connected to the liquid storage tank by inserting the extension-side tube in the first hole and outside the extension-side tube. A compression side damping valve arranged outside the outer tube is connected to the compression side passage through a compression side tube inserted through the second hole and the second boss portion, and the compression side damping valve is connected to the liquid storage tank through the outside of the compression side tube in the second hole.

4. The shock absorber according to any one of claims 1 to 3, wherein: The first tube and the second tube have opposite ends butted against each other, and the outer circumferences of the opposite ends have flat surfaces for alignment in the circumferential direction. A permanent magnet is mounted on the plane.

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