buffer

Abstract

The buffer (D) of the present application is provided with a cylinder (1), a guide (2) fitted on the inner periphery of the end portion of the cylinder (1), a piston rod (3) movably inserted into the cylinder (1), a piston (4) connected to the piston rod (3), and a sealing member (S) laminated on the guide (2) and through which the piston rod (3) is inserted; the sealing member (S) is provided with an annular sealing housing (7) having an annular recess (7a) on the inner periphery thereof, a sealing ring (8) provided with a base portion (8a) and a lip portion (8b) and housed in the annular recess (7a), an annular sealing support (9) laminated on the guide side of the base portion (8a) while being housed in the annular recess (7a), supporting the outer periphery of the sealing ring (8) and inhibiting the lip portion (8b) from expanding, and a stopper (10) mounted on the sealing housing (7) and preventing the sealing support (9) and the sealing ring (8) from falling off.

Description

Technical Field

[0001] The present invention relates to a buffer. Background Art

[0002] The shock absorber is used by being installed between a vehicle body and wheels in a vehicle, for example, and suppresses vibrations of the vehicle body and wheels by a damping force generated during expansion and contraction.

[0003] As disclosed in JP2019-158068A, the buffer includes, for example: a cylinder; an annular guide, which is embedded on the inner circumference of the end of the cylinder; a piston rod, which is inserted through the inner circumference of the guide and can be freely moved into the cylinder; and a piston, which is connected to the piston rod and inserted into the cylinder, and divides the cylinder into an extension side chamber and a compression side chamber filled with hydraulic oil; in addition, it also includes: a sealing unit, which is used to seal the outer circumference of the piston rod to prevent the hydraulic oil from leaking from the cylinder.

[0004] Specifically, the sealing unit comprises an annular seal retaining member having a seal accommodating portion, which is laminated on the atmosphere side of the guide and formed by a recessed portion whose inner diameter increases to a larger diameter at the center of the inner circumference on the guide side; a sealing member housed within the seal accommodating portion and sealing the outer circumference of the piston rod; and an annular seal holder housed outside the seal accommodating portion and supporting the outer circumference of the sealing member to prevent expansion of the sealing member's diameter. In this shock absorber structure, the seal member is supported by the seal holder to secure the piston rod, thereby achieving excellent sealing performance.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: JP2019-158068A Summary of the Invention

[0008] Problems to be solved by the invention

[0009] In conventional shock absorber assembly, the seal component and seal holder are pre-assembled onto the seal retaining member to form a seal unit. A dust seal, seal unit, and guide are then sequentially attached to the outer circumference of the piston rod. The piston is then attached to the tip of the piston rod to form the piston rod assembly. The completed piston rod assembly is then inserted into the cylinder and attached to the cylinder end by riveting.

[0010] However, since the sealing component and the sealing bracket in the sealing unit are only inserted into the sealing accommodating portion of the sealing retaining component, the sealing component and the sealing bracket may sometimes fall out of the sealing accommodating portion when the piston rod assembly is assembled or when the piston rod assembly is inserted into the cylinder. If the assembly of the buffer is completed without noticing this, it is very likely that the sealing component and the sealing bracket are assembled without being accommodated in the sealing accommodating portion of the sealing retaining component in the correct posture.

[0011] In this case, the sealing member cannot be fastened over the entire circumference of the piston rod with a uniform fastening force, and it is likely that stable sealing performance (sealing ability) cannot be obtained.

[0012] Therefore, an object of the present invention is to provide a shock absorber capable of exhibiting stable sealing performance while suppressing deterioration of a seal ring.

[0013] In order to solve the above-mentioned problems, the buffer of the present invention comprises: a cylinder; an annular guide member, which is fitted on the inner periphery of the end of the cylinder; a piston rod, which is inserted through the inner periphery of the guide member and is movably inserted into the cylinder; a piston, which is connected to the piston rod and is inserted into the cylinder, and divides the cylinder into an extension side chamber and a compression side chamber filled with a working fluid; and a sealing member, which is annular and laminated on the opposite side of the piston of the guide member, and is fitted on the inner periphery of the end of the cylinder while the piston rod is inserted through the inner periphery of the sealing member; the sealing member comprises: an annular A sealing housing having an annular recess on the inner periphery of the guide member side; a sealing ring having an annular base and an annular lip rising from the inner periphery of the base toward the guide member side and in sliding contact with the outer periphery of the piston rod, and accommodated in the annular recess; an annular sealing bracket, which is stacked on the guide member side of the base of the sealing ring and accommodated in the annular recess, supports the outer periphery of the lip and suppresses the expansion of the lip; a stopper, which is installed on the sealing housing and abuts the guide member side of the sealing bracket, and prevents the sealing bracket and the sealing ring from falling off.

[0014] According to the buffer constructed in this manner, the sealing ring and the sealing bracket are prevented from falling off from the annular recess of the sealing bracket by the block. Therefore, even if the sealing component is vibrated during the transportation of the piston rod assembly for assembling the sealing component on the piston rod, the sealing ring and the sealing bracket can be maintained in a state of being assembled on the sealing housing in the correct posture. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a longitudinal sectional view of a shock absorber in one embodiment.

[0016] Figure 2 It is a partially enlarged longitudinal sectional view of a buffer in one embodiment.

[0017] Figure 3This is an enlarged bottom view of a sealing member of a shock absorber according to one embodiment.

[0018] Figure 4 This is an enlarged longitudinal sectional view of a modified example of the fixing member in the sealing member.

[0019] Figure 5 This is an enlarged longitudinal sectional view of another modified example of the fixing member in the sealing member.

[0020] Figure 6 It is a partially enlarged longitudinal sectional view of a shock absorber including a sealing member having a stopper according to a first modified example.

[0021] Figure 7 This is an enlarged bottom view of a shock absorber including a sealing member having a stopper according to a first modification.

[0022] Figure 8 It is a partially enlarged longitudinal sectional view of a shock absorber including a sealing member having a stopper according to a second modified example.

[0023] Figure 9 This is an enlarged bottom view of a shock absorber including a sealing member having a stopper according to a second modification.

[0024] Figure 10 It is a partially enlarged longitudinal sectional view of a shock absorber including a sealing member having a stopper according to a third modified example.

[0025] Figure 11 This is an enlarged bottom view of a shock absorber including a sealing member having a stopper according to a third modified example.

[0026] Figure 12 It is an enlarged longitudinal sectional view of a shock absorber including a sealing member having a stopper according to a fourth modified example. DETAILED DESCRIPTION

[0027] The present invention will be described below based on the embodiments shown in the drawings. Figure 1 and Figure 2 As shown, a shock absorber D in one embodiment comprises: a cylinder 1; an annular guide 2 provided at the end of the cylinder 1; a piston rod 3 inserted through the inner circumference of the guide 2 and freely movable within the cylinder 1; a piston 4 connected to the piston rod 3 and inserted into the cylinder 1, dividing the interior of the cylinder 1 into an expansion-side chamber R1 and a compression-side chamber R2 filled with working fluid; and an annular seal member S, laminated on the opposite side of the guide 2 from the piston, fitted around the inner circumference of the end of the cylinder 1, and having the piston rod 3 inserted through its inner circumference. Furthermore, when using this shock absorber D, it can be installed between the body and wheels of a vehicle (not shown) to suppress vibrations between the body and wheels.

[0028] Next, each part of the buffer D is described in detail. Figure 1 As shown, in cylinder 1 Figure 1 The upper end of the cylinder is provided with an annular guide 2. The piston rod 3 is inserted through the inner periphery of the guide 2, and the guide 2 guides the piston rod 3 relative to the axial direction of the cylinder 1. Figure 1 Relative movement in the up and down directions.

[0029] The guide 2 is composed of: an annular main body 2a, which is fitted into the cylinder 1; a cylindrical bushing 2b, which is mounted on the inner periphery of the main body 2a and is in sliding contact with the outer periphery of the piston rod 3; an annular protrusion 2c, which is provided on the opposite side of the piston from the main body 2a. Figure 2 The convex portion 2c protrudes from the radial middle part of the upper end toward the opposite side of the piston; an annular recess 2d, which is provided on the outer periphery from the outer periphery of the convex portion 2c to the outer periphery of the main body 2a; an annular groove 2e, which is provided on the side closer to the inner periphery than the convex portion 2c of the main body 2a; a through hole 2f, which passes through from the piston side end of the main body 2a to the end of the convex portion 2c; and a notch 2g, which is provided on the convex portion 2c and passes from the inner periphery of the convex portion 2c to the through hole 2f.

[0030] When the guide member 2 constructed in this manner is inserted into the cylinder 1, its movement toward the piston 4 side is restricted by the C-ring 5 mounted on the inner periphery of the cylinder 1. Figure 1 The seal member S and the dust seal member 6 are laminated on the atmosphere side of the guide 2, which is the opposite side of the piston. The guide 2, the seal member S, and the dust seal member 6 are sandwiched and fixed to the cylinder 1 by the rivet portion 1a and the aforementioned C-ring 5. The rivet portion is formed on the cylinder 1 by caulking the pipe end of the cylinder 1.

[0031] Next, as described above, the piston rod 3 is inserted through the inner circumference of the guide 2. The piston rod 3 has a small-diameter portion 3a at its distal end, to which the piston 4, the expansion-side damping valve 11, and the compression-side damping valve 12 are attached. A piston nut 14 is threadedly engaged with the distal end of the small-diameter portion 3a, securing the piston 4, the expansion-side damping valve 11, and the compression-side damping valve 12 to the piston rod 3.

[0032] As mentioned above, the piston 4 is installed at the front end of the piston rod 3 and is slidably inserted into the cylinder 1, and the cylinder 1 is divided into an extension side chamber R1 and a compression side chamber R2. Figure 1 The compression side chamber is located above the piston 4. Figure 1 The expansion chamber R1 and the compression chamber R2 are located below the piston 4. Furthermore, a working fluid such as hydraulic oil is filled in the expansion chamber R1 and the compression chamber R2. Furthermore, the working fluid may be a liquid other than hydraulic oil, such as water or an aqueous solution, an electrorheological fluid, a magnetorheological fluid, or even a gas.

[0033] The piston 4 is provided with an expansion-side passage 4a and a compression-side passage 4b ​​for communicating the expansion-side chamber R1 and the compression-side chamber R2. Figure 1 The lower part of the middle part is used to open and close the extension side channel 4a. Figure 1 The compression side damping valve 12 is stacked on the lower end of the piston 4. Figure 1 The upper part of the compression channel 4b is used to open and close the compression channel 4b. Figure 1 The expansion-side damping valve 11 and the compression-side damping valve 12 are both laminated leaf valves formed by laminating a plurality of leaf valves made of annular plates. However, any valve capable of generating a damping force is not limited thereto. The expansion-side damping valve 11 is in the extension stroke of the shock absorber D, i.e., when the piston rod 3 moves relative to the cylinder 1. Figure 1 During the upward movement of the piston 4, the compression side damping valve 12 opens the valve and applies resistance to the flow of hydraulic oil flowing from the expansion side chamber R1 compressed by the piston 4 to the expanded compression side chamber R2 and flows through the expansion side passage 4a. Figure 1 During the downward movement, the valve is opened and resistance is applied to the flow of the hydraulic oil flowing from the compression-side chamber R2 compressed by the piston 4 to the expanded expansion-side chamber R1 and flowing through the compression-side passage 4b.

[0034] In addition, cylinder 1 Figure 1 The lower end of the cylinder 1 is closed, and although not shown in detail, it is provided with a bracket connecting the buffer D to the vehicle body or the wheel side. In addition, a free piston F for dividing the air chamber G is slidably inserted below the compression side chamber R2 in the cylinder 1.

[0035] When the shock absorber D extends, the expansion-side damping valve 11 provides resistance to the flow of hydraulic oil from the compressed expansion-side chamber R1 to the expanded compression-side chamber R2, and the shock absorber D generates a damping force to hinder extension. In addition, during the extension stroke of the shock absorber D, the piston rod 3 withdraws from the cylinder 1, and the free piston F moves to the Figure 1 The upward movement in the cylinder 1 is proportional to the volume of the piston rod 3 withdrawing from the cylinder 1 and the air chamber G is expanded, thereby compensating for the volume of the piston rod 3 withdrawing from the cylinder 1.

[0036] On the contrary, when the shock absorber D contracts, the flow of hydraulic oil from the compressed compression side chamber R2 to the expanded extension side chamber R1 is resisted by the compression side damping valve 12. In addition, when the shock absorber D contracts, the piston rod 3 enters the cylinder 1, and the free piston F moves to the Figure 1The piston rod 3 moves downward in the cylinder 1 by an amount proportional to the volume of the piston rod 3 entering the cylinder 1, shrinking the air chamber G and compensating for the volume of the piston rod 3 entering the cylinder 1. Therefore, when the shock absorber D is in the contraction stroke, the compression-side damping valve 12 resists the flow of the hydraulic oil, and the shock absorber D generates a compression-side damping force to prevent contraction.

[0037] Alternatively, the extension-side damping force and compression-side damping force of the shock absorber D can be adjusted by providing a bypass passage and a damping-force adjustment valve in the shock absorber D. The bypass passage bypasses the extension-side damping valve 11 and the compression-side damping valve 12 and connects the extension-side chamber R1 and the compression-side chamber R2. The damping-force adjustment valve is provided in the bypass passage. Furthermore, when the working fluid of the shock absorber D is an electrorheological fluid, a magnetorheological fluid, or an electromagnetic rheological fluid, an electric field generator that generates an electric field or a magnetic field generator that generates a magnetic field in the passage connecting the extension-side chamber R1 and the compression-side chamber R2 can be used as the damping force generating source in place of the extension-side damping valve 11 and the compression-side damping valve 12. Therefore, the structure of the shock absorber D that generates the damping force can be arbitrarily modified in design.

[0038] In the foregoing description, the volume of the piston rod 3 moving in and out of the cylinder 1 is compensated by providing a free piston F within the cylinder 1 to form an air chamber G. However, this volume compensation can also be achieved by providing a fluid reservoir outside the cylinder 1 that communicates with the compression-side chamber R2. In this case, a basic valve can be provided between the compression-side chamber R2 and the fluid reservoir. This basic valve is used to provide resistance to the flow of hydraulic oil from the compression-side chamber R2 to the fluid reservoir, thereby contributing to the generation of the compression-side damping force.

[0039] Next, the sealing member S is annularly laminated on the atmosphere side opposite to the piston side of the guide 2 and fitted to the inner periphery of the end of the cylinder 1 , and the piston rod 3 is inserted through the inner periphery.

[0040] Specifically, if Figure 2 and Figure 3 As shown, the sealing component S includes: an annular sealing housing 7 having an annular recess 7a on the inner periphery of the guide member 2 side; a sealing ring 8 accommodated in the annular recess 7a; an annular sealing bracket 9 accommodated in the annular recess 7a and used to support the outer periphery of the lip 8b of the sealing ring 8; and a stopper 10 mounted on the sealing housing 7 and preventing the sealing bracket 9 and the sealing ring 8 from falling off.

[0041] The sealing housing 7 is annular and has an annular recess 7a provided at the Figure 2 On the inner periphery of the lower end of the guide member 2 side end; annular seat 7b, which is provided Figure 2The annular recess 7a is formed as a stepped annular recess with the inner diameter on the guide 2 side expanding in the middle, and has a small diameter recess 7a1 on the inner side and a large diameter recess 7a2 on the outer side when viewed from the guide 2 side.

[0042] In addition, the retainer 7b rises from the outer periphery of the end portion of the seal housing 7 on the guide 2 side toward the guide 2 side and has an annular groove 7b1 on the inner periphery. Figure 2 An annular recess 7c is provided on the outer periphery of the upper end of the middle portion.

[0043] The seal ring 8 is formed from a synthetic resin or rubber and comprises an annular base portion 8a and an annular lip portion 8b that rises from the inner periphery of the base portion 8a toward the guide member 2 and in sliding contact with the outer periphery of the piston rod 3. The seal ring 8 is housed within the annular recess 7a of the seal housing 7. In this embodiment, the seal ring 8 is formed from fluororubber. More specifically, the axial height, or thickness, of the base portion 8a of the seal ring 8 is greater than the axial length of the small-diameter recess 7a1 of the annular recess 7a, and the outer diameter of the base portion 8a is slightly smaller to allow for engagement with the inner periphery of the small-diameter recess 7a1.

[0044] When seal ring 8 is housed within annular recess 7a of seal housing 7, base portion 8a of seal ring 8 is inserted into small-diameter recess 7a1. The inner diameter of lip portion 8b is smaller than the outer diameter of piston rod 3, providing an interference fit. When seal ring 8 is mounted on the outer circumference of piston rod 3, lip portion 8b secures the outer circumference of piston rod 3 with a predetermined tightening force, slidingly contacting the outer circumference of piston rod 3 and sealing the outer circumference of piston rod 3.

[0045] In this embodiment, the seal holder 9 is formed of acrylonitrile-butadiene rubber, has an annular shape, and is housed within the annular recess 7a of the seal housing 7. More specifically, the seal holder 9 includes an annular stopper portion 9a that protrudes radially inward from the inner circumference on the guide member 2 side. Furthermore, the axial height of the seal holder 9 is equal to the axial height of the large-diameter recess 7a2 of the annular recess 7a, and the outer diameter is approximately equal to the inner diameter of the large-diameter recess 7a2. Furthermore, the seal holder 9 is fitted into the large-diameter recess 7a2 of the annular recess 7a and housed within the annular recess 7a, with the end surface on the opposite side of the guide member contacting the end surface of the base 8a of the seal ring 8 on the guide member side. Furthermore, the inner diameter of the stopper portion 9a of the seal holder 9 is smaller than the outer diameter of the portion of the lip 8b where the stopper portion 9a contacts when the piston rod 3 is inserted into the inner circumference. When the seal holder 9 is fitted into the large-diameter recess 7a2, the stopper portion 9a supports the outer circumference of the lip 8b. When the piston rod 3 is inserted through the inner circumference of the lip 8b, the stopper portion 9a supports the outer circumference of the lip 8b and suppresses the expansion of the lip 8b, thereby keeping the lip 8b in close contact with the outer circumference of the piston rod 3. In this way, the seal holder 9 supports the lip 8b of the seal ring 8 from the outer circumference, suppressing the expansion of the lip 8b fitted to the outer circumference of the piston rod 3 and stabilizing the surface pressure of the portion of the lip 8b in contact with the piston rod 3. Since the seal ring 8 is made of fluororubber, it exhibits excellent high-temperature resistance and sealing performance, but its low-temperature resistance is somewhat poor. However, in the shock absorber D of this embodiment, the seal ring 8 is supported by the seal holder 9 made of acrylonitrile-butadiene rubber, which has excellent low-temperature resistance. This ensures excellent sealing performance over a wide temperature range, from high to low temperatures. Thus, when the seal ring 8 is formed of a synthetic resin or rubber that exhibits excellent sealing performance even at high temperatures, and the seal holder 9 is formed of a synthetic resin or rubber that also exhibits excellent low-temperature resistance, excellent sealing performance can be achieved over a wide temperature range, from high to low temperatures. However, the seal ring 8 and the seal holder 9 may be formed of the same synthetic resin or rubber.

[0046] The stopper 10 comprises: a stopper plate 10a which is annular and fits into the inner periphery of the retainer 7b and contacts the sealing bracket 9; and a C-shaped retainer ring 10b which is mounted on the retainer 7b and serves as a fixing member for fixing the stopper plate 10a to the sealing housing 7.

[0047] The stop plate 10a includes: an inner peripheral portion 10a1, whose inner diameter is larger than the outer diameter of the piston rod 3, and forms an annular gap H1 between it and the piston rod 3, and is opposite to the sealing bracket 9, forming an annular gap H2 between it and the sealing bracket 9; an outer peripheral portion 10a2, which is connected to the outer periphery of the inner peripheral portion 10a1, abuts against the sealing bracket 9, and is embedded in the inner periphery of the seat 7b; 6 through holes 10a3, which are evenly spaced and arranged on the same circle in the middle part of the inner peripheral portion 10a1 and pass through the inner peripheral portion 10a1; and a chamfered portion 10a4, which is arranged on the outer periphery of the guide member side of the outer peripheral portion 10a2.

[0048] The stop plate 10a constructed in this manner has its outer periphery fitted onto the inner periphery of the support 7b and assembled onto the sealed housing 7, and is fixed to the sealed housing 7 by means of a retaining ring 10b mounted on the annular groove 7b1 provided on the inner periphery of the support 7b. In addition, when the stop plate 10a is inserted into the support 7b in the correct direction, the chamfered portion 10a4 is opposed to the annular groove 7b1 of the support 7b, and allows the retaining ring 10b to be mounted on the annular groove 7b1. That is, the length from the upper end of the stop plate 10a to the chamfered portion 10a4 is equal to or slightly shorter than the length from the abutting surface of the sealed housing 7 against which the stop plate 10a abuts to the annular groove 7b1 of the support 7b. Therefore, when the inside and outside (at Figure 2 When the stop plate 10a is turned upside down (in the figure), and the stop plate 10a is fitted into the seat 7b, the outer periphery of the stop plate 10a is opposite to the annular groove 7b1, and the retaining ring 10b cannot be installed in the annular groove 7b1.

[0049] When the stopper plate 10a is fixed to the seal housing 7, the seal holder 9, which abuts the outer circumference 10a2 of the stopper plate 10a, is prevented from falling out of the large-diameter recess 7a2 of the annular recess 7a. Furthermore, the seal ring 8, whose base 8a abuts the seal holder 9, is also prevented from falling out of the small-diameter recess 7a1 of the annular recess 7a. Therefore, when the stopper 10, consisting of the stopper plate 10a and the retaining ring 10b, is mounted on the seal housing 7, the seal ring 8 and the seal holder 9 are integrated, preventing them from falling out of the annular recess 7a of the seal housing 7. Furthermore, because the base 8a of the seal ring 8 is compressed in the axial direction while being held between the seal holder 9 and the seal housing 7, even if force is applied from the seal housing 7 toward the guide member, the seal holder 9 is secured by the stopper 10 and thus does not fall out of the seal housing 7.

[0050] As described above, when the seal ring 8 , the seal holder 9 , and the stopper 10 are assembled to the seal housing 7 , the seal ring 8 , the seal holder 9 , and the stopper 10 are integrated to form the seal member S as a seal assembly.

[0051] A dust-proof sealing member 6 is stacked on the atmosphere side opposite to the piston of the sealing member S. The dust-proof sealing member 6 has a core shaft 6a made of a ring-shaped plate, a ring-shaped dust-proof sealing member 6b integrated with the inner periphery of the core shaft 6a on the atmosphere side opposite to the guide, and a ring-shaped outer periphery sealing member 6c integrated with the outer periphery of the core shaft 6a on the guide side.

[0052] Further, when the dust-proof sealing member 6 is inserted into the cylinder 1 in a state that the core shaft 6a is stacked on the end of the guide opposite to the sealing housing 7 of the sealing member S, the outer periphery sealing member 6c is housed in the recess 7c of the sealing housing 7 in a compressed state, is tightly attached to the recess 7c of the sealing housing 7 and the inner periphery of the cylinder 1, and seals between the sealing member S and the cylinder 1. In addition, the dust-proof sealing member 6 makes the dust-proof sealing member 6b in sliding contact with the outer periphery of the piston rod 3, and prevents dust or dirt or water from entering into the cylinder 1 from around the outer periphery of the piston rod 3.

[0053] The damper D configured in this way is assembled in the following order. First, as described above, the seal ring 8, the seal holder 9, and the stopper 10 are assembled on the sealing housing 7 to assemble the sealing member S.

[0054] Next, the piston rod 3 is inserted through the inner periphery of the dust-proof sealing member 6, the sealing member S, and the guide 2 in this order from the front end side, and the dust-proof sealing member 6, the sealing member S, and the guide 2 are assembled on the piston rod 3.

[0055] Finally, the compression-side damping valve 12, the piston 4, and the extension-side damping valve 11 are assembled in this order on the small-diameter portion 3a of the front end of the piston rod 3, and are fixed to the piston rod 3 by the piston nut 14.

[0056] In this way, as described above, the piston rod assembly is obtained by assembling the piston 4, the extension-side damping valve 11, the compression-side damping valve 12, the guide 2, the sealing member S, and the dust-proof sealing member 6 on the piston rod 3.

[0057] Next, the piston rod assembly is inserted into the cylinder 1 from the piston 4 side, and the piston 4 and the compression-side damping valve 12 are completely housed in the cylinder 1, and then the C-ring 5 is installed on the inner periphery of the open end of the cylinder 1. Then, the piston rod assembly is further inserted into the cylinder 1 so that the guide 2 is in abutment with the C-ring 5, and the guide 2, the sealing member S, and the dust-proof sealing member 6 are housed in the cylinder 1 in a stacked state.

[0058] After the guide 2, seal member S, and dust seal 6 are stacked and housed within the cylinder 1 while the guide 2 and C-ring 5 are in contact, the open end of the cylinder 1 is riveted. The guide 2, seal member S, and dust seal 6 are clamped between the rivet 1a and the C-ring 5 and secured to the cylinder 1. Furthermore, the injection of working fluid into the expansion-side chamber R1 and the compression-side chamber R2 can be performed during the process of inserting the piston rod assembly into the cylinder 1, or after that process and before the riveting of the cylinder 1. Furthermore, gas can be injected into the gas chamber G, for example, after the piston rod assembly is assembled into the cylinder 1, from the lower end of the cylinder 1. After gas injection, the bracket is then attached to the lower end of the cylinder 1. The assembly process for the shock absorber D is illustrative and can be modified.

[0059] In the buffer D assembled in this manner, the sealing component S includes: an annular sealing housing 7, which has an annular recess 7a on the inner periphery of the guide side; a sealing ring 8, which has an annular base 8a and an annular lip 8b that rises from the inner periphery of the base 8a toward the guide side and is in sliding contact with the outer periphery of the piston rod 3, and is accommodated in the annular recess 7a; an annular sealing bracket 9, which is stacked on the guide side of the base 8a of the sealing ring 8 and is accommodated in the annular recess 7a, while supporting the outer periphery of the sealing ring 8 and suppressing the expansion of the lip 8b; and a stopper 10, which is mounted on the sealing housing 7 and abuts against the guide side of the sealing bracket 9 to prevent the sealing bracket 9 and the sealing ring 8 from falling off.

[0060] Therefore, when the piston rod assembly is assembled by assembling the sealing component S on the outer periphery of the piston rod 3 or when the piston rod assembly is inserted into the cylinder 1, the sealing ring 8 and the sealing bracket 9 will not fall off from the sealing housing 7 and will be maintained in a state of being accommodated in the annular recess 7a in the correct assembly posture.

[0061] Even when the piston rod assembly is assembled to the cylinder 1 , the seal ring 8 and the seal holder 9 of the seal member S can be assembled in a state where they are correctly accommodated in the annular recess 7 a of the seal housing 7 .

[0062] Therefore, the sealing ring 8 is positioned at an appropriate position relative to the piston rod 3 and is in sliding contact with the outer periphery of the piston rod 3, and can tighten the entire circumference of the piston rod 3 with a uniform tightening force. Even if the piston rod 3 moves up and down, the buffer D can also exert stable sealing performance.

[0063] As described above, the seal member S is sandwiched and fixed to the cylinder 1 by the rivet portion la of the cylinder 1 and the C-ring 5 together with the guide 2 and the dust seal member 6. At this time, since the seat 7b is accommodated in the recessed portion 2d of the outer periphery of the guide 2, the stopper plate 10a abuts against the protrusion 2c of the guide 2 while being pressed against the seal housing 7 by the axial force received from the rivet portion la, and is fixed to the cylinder 1. Since the stopper plate 10a abuts against the outer periphery of the seal holder 9, the axial force is also applied to the seal holder 9, and even if the lip portion 8b of the seal ring 8 is expanded in diameter and a force to push out the seal holder 9 from the large-diameter recessed portion 7a2 is generated, the seal holder 9 does not fall out of the large-diameter recessed portion 7a2. In addition, the annular recessed portion 7a can be formed by an annular recessed portion whose inner diameter does not expand in diameter in the middle and whose inner diameter does not change, but when the annular recessed portion 7a has the small-diameter recessed portion 7al that accommodates the base portion 8a of the seal ring 8 and the large-diameter recessed portion 7a2 that accommodates the seal holder 9, the seal holder 9 does not excessively press the base portion 8a of the seal ring 8 by the axial force received from the stopper plate 10a, and thus the seal ring 8 can be protected.

[0064] Further, the inner diameter of the stopper plate 10a of the stopper 10 is larger than the outer diameter of the piston rod 3, and the inner peripheral portion 10al of the stopper plate 10a is opposed to the seal holder 9 with the gap H2 therebetween, although the stopper plate 10a does not interfere with the piston rod 3. Also, as described above, the stopper plate 10a is pressed by the axial force and is fixed to the cylinder 1. Therefore, even if the seal holder 9 is deformed in such a manner that the seal holder 9 is lifted from the seal housing 7 due to the lip portion 8b passing through the piston rod 3, the seal holder 9 can be supported and the sealing performance of the lip portion 8b against the piston rod 3 can be maintained. Further, even if the inner periphery of the seal holder 9 abuts against the stopper plate 10a due to such deformation of the seal holder 9, since the gap H2 is maintained in a state of communicating with the elongation-side chamber Rl through the through-hole 2f of the guide 2 by the through-hole 10a3 provided in the inner peripheral portion 10al of the stopper plate 10a, the tightening force of the lip portion 8b of the seal ring 8 against the piston rod 3 can be improved by applying the high pressure in the elongation-side chamber Rl compressed when the damper D performs the elongation operation to the seal holder 9. Further, the high pressure in the elongation-side chamber Rl can also be applied to the lip portion 8b through the annular gap Hl between the stopper plate 10a and the piston rod 3. Therefore, even when the elongation-side chamber Rl becomes high pressure and the damper D performs the elongation operation, the pressure in the elongation-side chamber Rl can be applied to the seal ring 8 and the seal holder 9, so that the working fluid can be effectively prevented from leaking from the cylinder 1. In addition, the number of the through-holes 10a3 provided in the stopper plate 10a can be arbitrarily set as long as the number is one or more.

[0065] Furthermore, if the working fluid contains contaminants such as chips generated during the processing of the buffer D, the working fluid containing the contaminants may flow through the through-hole 2f into the gap between the stop plate 10a and the guide 2 during the extension operation of the buffer D. In this case, the contaminants are drawn into the annular groove 2e of the guide 2 to prevent them from returning to the expansion-side chamber R1 and the compression-side chamber R2. Furthermore, the contaminants can be recovered from the expansion-side chamber R1 and the compression-side chamber R2 by the repeated extension and contraction operation of the buffer D, thereby purifying the hydraulic oil in the expansion-side chamber R1 and the compression-side chamber R2.

[0066] As described above, the shock absorber D of this embodiment comprises: a cylinder 1; an annular guide 2, which is fitted on the inner periphery of the end portion of the cylinder 1; a piston rod 3, which is inserted through the inner periphery of the guide 2 and is inserted into the cylinder 1 so as to be movable; a piston 4, which is connected to the piston rod 3 and is inserted into the cylinder 1, and divides the cylinder 1 into an expansion side chamber R1 and a compression side chamber R2 filled with a working fluid; and a sealing member S, which is annular and is stacked on the opposite side of the piston of the guide 2, and is fitted on the inner periphery of the end portion of the cylinder 1, while the piston rod 3 is inserted into the inner periphery thereof; the sealing member S comprises: an annular sealing housing 7 , which has an annular recess 7a on the inner periphery of the guide side; a sealing ring 8, which has an annular base 8a and an annular lip 8b that rises from the inner periphery of the base 8a toward the guide side and is in sliding contact with the outer periphery of the piston rod 3, and is accommodated in the annular recess 7a; an annular sealing bracket 9, which is stacked on the guide side of the base 8a of the sealing ring 8 and is accommodated in the annular recess 7a, while supporting the outer periphery of the sealing ring 8 and suppressing the expansion of the lip 8b; a stopper 10, which is mounted on the sealing housing 7 and abuts against the guide side of the sealing bracket 9, and prevents the sealing bracket 9 and the sealing ring 8 from falling off.

[0067] In the shock absorber D constructed in this manner, when the shock absorber D is assembled, the stopper 10 of the sealing member S prevents the seal ring 8 and seal holder 9 from falling out of the seal housing 7, maintaining their correctly assembled state. Therefore, according to the shock absorber D of this embodiment, since the seal ring 8 and seal holder 9 are maintained in their correctly assembled state to the seal housing 7, the seal ring 8 can be tightened with uniform tightening force around the entire circumference of the piston rod 3, thereby achieving stable sealing performance.

[0068] Further, since the seal ring 8 and the seal holder 9 are not detached from the seal housing 7 by the stopper 10 of the seal member S and are maintained in a state of being assembled in a correct posture, it is possible to remove chips and the like, which are contaminating substances, by blowing or vacuuming after the piston rod assembly is assembled, while the seal member S is distanced from the guide 2 and the dust seal member 6. Further, since the seal member S can hold the seal ring 8 and the seal holder 9 even if it is not adjacent to the guide 2, only the piston rod 3 is required to have dimensional accuracy, and the guide 2 is not required to have dimensional accuracy, so that it is possible to reduce the machining accuracy requirement and machining cost.

[0069] Further, in the damper D of the present embodiment, the seal housing 7 has an annular seat 7b on the outer periphery on the guide side, the stopper 10 is annular and fitted on the inner periphery of the seat 7b, and has a stop plate 10a having a larger inner diameter than the outer diameter of the piston rod 3 and a retainer ring (fixing member) 10b mounted on the seat 7b and fixing the stop plate 10a to the seal housing 7, while abutting against the seal holder 9. In the damper D configured in this way, the stop plate 10a is fitted on the seat 7b and can be positioned in the radial direction, and the stop plate 10a is fixed to the seal housing 7 by the retainer ring (fixing member) 10b using the seat 7b. Therefore, according to the damper D configured in this way, the stop plate 10a is fixed to the seal housing 7 in the appropriate position, and it is possible to achieve the purpose of preventing the seal ring 8 and the seal holder 9 from being detached. Further, when the extension-side chamber R1 becomes high pressure and the damper D performs the extension operation, it is possible to apply the pressure in the extension-side chamber R1 to the seal ring 8, to effectively prevent the working fluid from leaking from the cylinder 1.

[0070] Furthermore, in the shock absorber D of this embodiment, the stopper plate 10a includes an inner peripheral portion 10a1 that faces the seal holder 9 and forms an annular gap H2 with the seal holder 9; an outer peripheral portion 10a2 that is connected to the outer periphery of the inner peripheral portion 10a1, abuts against the seal holder 9, and engages with the inner periphery of the retainer 7b; one or more through-holes 10a3 that penetrate the inner peripheral portion 10a1; and a chamfered portion 10a4 provided on the outer periphery of the outer peripheral portion 10a2 on the guide side. With this structure, the shock absorber D, with the gap H2 formed between the stopper plate 10a and the seal holder 9, can avoid interference between the stopper plate 10a and the lip portion 8b of the seal ring 8, preventing excessive tightening force from being applied to the lip portion 8b, and thus suppressing deterioration of the seal ring 8 due to wear. Furthermore, with the shock absorber D thus configured, the inner circumference 10a1 of the stopper plate 10a faces the seal holder 9 with a gap H2 therebetween. Therefore, even if the seal holder 9 deforms in a floating manner due to the expansion of the lip portion 8b of the seal ring 8, the inner circumference 10a1 of the stopper plate 10a supports the seal holder 9, maintaining the tightening force of the lip portion 8b and thus achieving excellent sealing performance. Furthermore, the through-hole 10a3 provided in the stopper plate 10a allows the high pressure within the expansion-side chamber R1 of the shock absorber D to act on the seal holder 9 when the pressure within the expansion-side chamber R1 increases and the shock absorber D extends. This allows the shock absorber D to effectively prevent leakage of the working fluid from the cylinder 1 even during the extension operation.

[0071] Furthermore, in the shock absorber D of this embodiment, since the retaining member is a retaining ring 10b mounted on the inner circumference of the retainer 7b, the stopper plate 10a can be fixed to the seal housing 7 even without increasing the axial length of the retainer 7b. Therefore, with the shock absorber D using the retaining ring 10b as the retaining member, the increase in the axial length of the seal member S can be suppressed, and the stroke length can be easily ensured. Furthermore, since the stopper plate 10a includes the chamfered portion 10a4, if the operator installing the stopper plate 10a on the seal housing 7 reverses the stopper plate 10a, the outer circumference of the stopper plate 10a faces the annular groove 7b1 of the retainer 7b, making it impossible to attach the retaining ring 10b to the retainer 7b and thus securing the stopper plate 10a. This prevents incorrect assembly, such as the front-side-down assembly of the stopper plate 10a on the seal housing 7.

[0072] Furthermore, since the stopper plate 10a is fixed by mounting the retaining ring 10b on the seat 7b, the stopper plate 10a can be easily fixed to the sealing housing 7, but it may also be fixed as shown in FIG. Figure 4As shown in FIG. 1 , the stopper plate 10a can be fixed to the sealing housing 7 by riveting the front end of the retainer 7b to the inner circumference while the stopper plate 10a is accommodated, thereby replacing the retaining ring 10b. In this case, the fixing member becomes the riveted portion 7d at the front end of the retainer 7b. According to the buffer D constructed in this way, the retaining ring 10b is not required, so the number of parts can be reduced. Figure 5 As shown, the stopper plate 10a can also be fixed to the sealed housing 7 by pressing the stopper plate 10a into the inner periphery of the retainer 7b. In this case, the retainer 7b becomes the fixing member, and according to the buffer D constructed in this way, the retaining ring 10b is not required, so the number of parts can be reduced.

[0073] In addition, the stopper can also be constructed in the following modified form. Figure 6 and Figure 7 As shown, the stopper 20 of the first variant comprises: a stop plate 21, which is annular, embedded in the inner periphery of the seat 7b and abuts against the sealing bracket 9, and the inner diameter is larger than the outer diameter of the piston rod 3; and a fixing component 22, which is mounted on the seat 7b and fixes the stop plate 21 to the sealing housing 7.

[0074] The retaining plate 21 is annular and fits on the inner periphery of the retaining seat 7b. The retaining seat 7b of the sealing housing 7 is annular with an outer diameter smaller than the maximum outer diameter of the sealing housing 7, protrudes from the sealing housing 7 toward the piston, and forms an annular gap with the cylinder 1.

[0075] The fixing member 22 comprises a main body 22a, which is annular and contacts the guide side of the stop plate 21; and six clamping arms 22b, which are arranged on the outer periphery of the main body 22a and grip the outer periphery of the retainer 7b. Furthermore, the main body 22a comprises six notches 22a1, each having an inner diameter larger than the outer diameter of the piston rod 3 and opening from the inner periphery toward the outer periphery. The inner diameter of the stop plate 21 is greater than or equal to the diameter of a circumscribed circle C1, which is in contact with the distal ends of the notches 22a1 and is smaller than the outer diameter of the seal holder 9. When the stop plate 21 is engaged with the inner periphery of the retainer 7b, it contacts the guide side of the seal holder 9.

[0076] The front end portion of the clamping arm 22b of the fixing member 22 is curved, and when the fixing member 22 is viewed from the side, it has a hook-shaped clamping claw shape. When it is engaged with the outer periphery of the support 7b, it tightens and grips the outer periphery of the support 7b. Therefore, by engaging the clamping arm 22b with the outer periphery of the support 7b, the fixing member 22 can be fixed to the sealed housing 7. In addition, the number of clamping arms 22b provided can be arbitrarily set as long as it is three or more. When there are three or more clamping arms 22b, and they are evenly spaced on the outer periphery of the main body 22a, the fixing member 22 can be fixed to the support 7b without deviation in the circumferential direction.

[0077] Furthermore, as described above, when the fixing member 22 is mounted on the seal housing 7 with the stopper plate 21 fitted into the retainer 7b of the seal housing 7, the stopper plate 21 is fixed to the seal housing 7. Since the stopper plate 21 abuts against the outer peripheral side of the guide side surface of the seal holder 9 and is fixed to the seal housing 7, the seal ring 8 and the seal holder 9 in the annular recess 7a are prevented from falling out of the seal housing 7.

[0078] In addition, since the outer diameter of the seat 7b is smaller than the inner diameter of the cylinder 1, even if the clamping arm 22b of the fixing member 22 grips the outer periphery of the seat 7b, the clamping arm 22b will not interfere with the cylinder 1, and the sealing member S1 can be easily inserted into the cylinder 1.

[0079] In addition, the axial length, i.e., the thickness, of the stop plate 21 of the stop block 20 of the first variant in the buffer D of this embodiment is shorter than the axial length of the seat 7b, and the axial length of the front end portion of the clamping arm 22b is also shorter than the axial length of the seat 7b. Therefore, when the fixing component 22 is installed on the seat 7b, the main body 22a of the fixing component 22 is tightly attached to the guide side of the stop plate 21, so that the stop plate 21 can be fixed to the sealed housing 7 without looseness.

[0080] In the sealing component S1 constructed in this manner, since the outer periphery of the seat 7b is gripped by the clamping arm 22b and the fixing component 22 is fixed to the sealing housing 7, the sealing component S1 can be easily assembled directly by manpower without using tools by reducing the tightening force of the clamping arm 22b on the seat 7b. In addition, since the outer periphery of the seat 7b is gripped by the clamping arm 22b and the fixing component 22 is fixed to the sealing housing 7, the stopper plate 21 can be set as a thin-walled ring, and the axial length of the sealing component S1 can be shortened. Figure 2 、 Figure 4 and Figure 5 In the case of the stopper 10 shown, cutting is required to provide the stopper plate 10a with a thinner inner peripheral portion 10a1 and a thicker outer peripheral portion 10a2, or to provide the chamfered portion 10a4 on the outer periphery. Since the outer periphery of the stopper plate 10a needs to be clamped, the wall thickness of the stopper plate 10a must be thick. Therefore, as in the stopper 20 of the first modified example, when the fixing member 22 includes an annular main body portion 22a that abuts the guide side surface of the stopper plate 21, and six clamping arms 22b provided on the outer periphery of the main body portion 22a and gripping the outer periphery of the retainer 7b, the wall thickness of the stopper plate 21 can be reduced, and the axial length of the sealing member S1 can be shortened.

[0081] The sealing component S1 constructed in this manner is pre-assembled, similar to the sealing component S, and then incorporated into the piston rod assembly and inserted into the cylinder 1. It is then clamped and secured to the cylinder 1 by the rivet portion 1a and the C-ring 5. Even during assembly of the piston rod assembly or insertion into the cylinder 1, the stopper 20 prevents the sealing ring 8 and the sealing holder 9 from falling out of the annular recess 7a of the seal housing 7, maintaining the sealing ring 8 and the sealing holder 9 properly housed within the annular recess 7a.

[0082] Therefore, according to the shock absorber D including the sealing member S1 constructed in this manner, since the seal ring 8 and the seal holder 9 are maintained in the correct assembled state on the seal housing 7, the seal ring 8 can be tightened with uniform tightening force over the entire circumference of the piston rod 3, thereby achieving stable sealing performance. Furthermore, since the outer circumference of the retainer 7b is grasped by the clamping arms 22b and the fixing member 22 is fixed to the seal housing 7, the stopper plate 21 can be formed into a thin-walled ring, and the axial length of the sealing member S1 can be shortened. Therefore, according to the shock absorber D including the sealing member S1, it is easier to ensure a sufficient stroke length.

[0083] Furthermore, when sealing member S1 is secured to cylinder 1, since retainer 7b is accommodated in recessed portion 2d on the outer periphery of guide 2, main body 22a of fixing member 22 abuts against protrusion 2c of guide 2, and, utilizing the axial force received from rivet 1a, presses seal housing 7 together with stopper plate 21, thereby securing sealing member S1 to cylinder 1. Since the inner periphery of main body 22a of fixing member 22, supported by protrusion 2c of guide 2, faces the inner periphery of seal holder 9, even if insertion into the inner periphery of piston rod 3 causes lip 8b to expand in diameter and seal holder 9 to deform so as to float from seal housing 7, the inner periphery of fixing member 22 maintains support for seal holder 9. In addition, by providing the stop plate 21, a gap is formed between the fixing component 22 and the sealing bracket 9, thereby avoiding interference between the fixing component 22 and the lip 8b of the sealing ring 8, and no excessive tightening force is applied to the lip 8b, thereby suppressing deterioration of the sealing ring 8 caused by wear.

[0084] Furthermore, since the fixing member 22 of the stopper 20 has six notches 22a1 on its inner circumference, and the stopper plate 21 has an inner diameter greater than or equal to the diameter of the circumscribed circle C1, the circumscribed circle C1 and the tips of the notches 22a1 are in contact with each other and abut against the seal holder 9. Therefore, even if the seal holder 9 deforms to float away from the seal housing 7 and abuts against the inner circumference of the fixing member 22, the pressure in the expansion-side chamber R1 can still act on the seal holder 9 through the notches 22a1. Therefore, by applying the high pressure within the expansion-side chamber R1, which is compressed during the expansion of the damper D, to the seal holder 9, the tightening force of the lip 8b of the seal ring 8 on the piston rod 3 can be enhanced. Furthermore, even if the seal holder 9 deforms and abuts against the fixing member 22, the pressure in the expansion-side chamber R1 can still act on the lip 8b of the seal ring 8 because the inner diameter of the fixing member 22 is larger than the outer diameter of the piston rod 3. The number of the cutouts 22a1 provided in the main body 22a of the fixing member 22 may be arbitrarily set as long as it is one or more.

[0085] Next, the stopper 30 of the second modified example will be described. Figure 8 and Figure 9 As shown, the stopper 30 of the second variant includes: a stop plate 31, which is annular, embedded in the inner periphery of the seat 7b and abuts against the sealing bracket 9, and the inner diameter is larger than the outer diameter of the piston rod 3; and a fixing component 32, which is mounted on the seat 7b and fixes the stop plate 31 to the sealing housing 7.

[0086] The stopper plate 31 is annular and fits onto the inner circumference of the retainer 7b. The retainer 7b in the sealed housing 7 is annular, with an inner diameter that widens in the middle. It has a stepped portion 7b2 on its inner circumference. Furthermore, the inner circumference on the opening side is tapered from the stepped portion 7b2, increasing in diameter from the opening end toward the inside. The inner diameter of the stepped portion 7b2 is larger than the inner diameter of the opening end. This tapered shape of the retainer 7b's inner circumference, closer to the opening end than the stepped portion 7b2, creates a larger inner diameter portion on the inner circumference than the opening end.

[0087] The fixing member 32 comprises an annular main body 32a that abuts the guide side of the stopper plate 31, and three jaws 32b disposed on the outer periphery of the main body 32a and extending into the inner periphery of the retainer 7b, the aforementioned large-diameter portion. Furthermore, the main body 32a comprises six notches 32a1, each with an inner diameter larger than the outer diameter of the piston rod 3, opening from the inner periphery toward the outer periphery. Furthermore, the inner diameter of the stopper plate 31 is greater than or equal to the diameter of a circumscribed circle C2, which is in contact with the distal ends of the notches 32a1 and is smaller than the outer diameter of the seal holder 9. When the stopper plate 31 is engaged within the inner side of the stepped portion 7b2 on the inner periphery of the retainer 7b, it abuts the guide side of the seal holder 9.

[0088] In addition, the outer diameter of the main body 32a is larger than the outer diameter of the stop plate 31 and the smallest diameter of the inner circumference of the seat 7b, and the fixing member 32 is accommodated closer to the opening side than the step portion 7b2 of the seat 7b. The clamping claws 32b of the fixing member 32 protrude radially from the outer circumference of the main body 32a, forming a shape with a tapered front end. In addition, the diameter of the circumscribed circle C3 connected to the front end of the clamping claws 32b is larger than the inner diameter of the open end of the seat 7b. Therefore, when the fixing member 32 is pressed into the seat 7b, the clamping claws 32b temporarily bend and enter the seat 7b. When they return to their original state from the bent state due to their own restoring force, they are stuck on the tapered inner circumferential surface of the seat 7b, and the fixing member 32 is fixed to the sealing housing 7. In addition, the number of clamping claws 32b provided can be arbitrarily set as long as it is two or more. When there are three or more claws 32b and they are evenly spaced on the outer periphery of the main body 32a, the fixing member 32 can be fixed to the retainer 7b without looseness. In addition, the large diameter portion provided on the inner periphery of the retainer 7b can also be provided by providing an annular groove provided along the inner periphery.

[0089] Furthermore, when the fixing member 32 is mounted on the seal housing 7 as described above, with the stopper plate 31 fitted into the inner side of the smaller inner diameter of the retainer 7b of the seal housing 7, the stopper plate 31 is fixed to the seal housing 7. Since the stopper plate 31 abuts against the outer peripheral side of the guide side of the seal holder 9 and is fixed to the seal housing 7, the seal ring 8 and the seal holder 9 in the annular recess 7a are prevented from falling out of the seal housing 7.

[0090] In addition, if the axial length, i.e., the thickness, of the stop plate 31 of the stop block 30 of the second variant of the buffer D of this embodiment is set to be greater than or equal to the height of the step portion 7b2 of the support 7b, then when the fixing component 32 is mounted on the support 7b, the main body 32a of the fixing component 32 is tightly attached to the guide side of the stop plate 31, thereby enabling the stop plate 31 to be fixed to the sealed housing 7 without looseness.

[0091] In the sealing component S2 thus constructed, the inner circumference of the retainer 7b, i.e., the inner circumference closer to the open end than the stepped portion 7b2, is tapered to form a larger diameter portion with a diameter greater than the inner diameter of the open end. The jaws 32b enter this portion to secure the fixing member 32 to the sealing housing 7. Consequently, by shortening the radial length of the jaws 32b, the sealing component S2 can be easily assembled manually without the use of tools. Furthermore, since the jaws 32b enter the larger diameter portion with a diameter greater than the inner diameter of the open end to secure the fixing member 32 to the sealing housing 7, the stopper plate 31 can be formed as a thinner annular ring. Similarly to the sealing component S1, the axial length of the sealing component S2 can be shortened.

[0092] The seal member S2 configured in this way, like the seal members S and S1, after being assembled beforehand, is assembled into the piston rod assembly and inserted into the cylinder 1, is clamped and fixed to the cylinder 1 by the rivet portion la and the C-ring 5. Even when the piston rod assembly is assembled or when it is inserted into the cylinder 1, the seal ring 8 and the seal holder 9 can be prevented from falling out of the annular recessed portion 7a of the seal housing 7 by the stopper 30, and the state of the seal ring 8 and the seal holder 9 being housed in the annular recessed portion 7a in the correct posture is maintained.

[0093] Therefore, according to the damper D provided with the seal member S2 configured in this way, since the state of the seal ring 8 and the seal holder 9 being assembled on the seal housing 7 in the correct posture is maintained, the seal ring 8 can be fastened on the entire circumference of the piston rod 3 with a uniform fastening force, and stable sealing performance can be exhibited. Further, since the structure of the clamping jaw 32b being made to enter the large-diameter portion having a larger diameter than the inner diameter of the opening end and the fixing member 32 being fixed to the seal housing 7 is adopted, the stopper 31 can be made into a circular ring having a thin wall thickness, and the axial length of the seal member S2 can be shortened, and therefore, according to the damper D provided with the seal member S2, the stroke length can be more easily ensured; wherein the opening end is provided at the inner periphery of the seat 7b, i.e., at the opening end side than the stepped portion 7b2.

[0094] Further, when the seal member S2 is fixed to the cylinder 1, since the seat 7b is housed in the recessed portion 2d of the outer periphery of the guide 2, the main body portion 32a of the fixing member 32 abuts against the convex portion 2c of the guide 2, and is fixed to the cylinder 1 while being pressed against the seal housing 7 together with the stopper 31 by the axial force received from the rivet portion la. Since the inner peripheral portion of the main body portion 32a of the fixing member 32 supported by the convex portion 2c of the guide 2 opposes the inner periphery of the seal holder 9, even if the seal holder 9 is deformed in a manner of floating up from the seal housing 7 due to the expansion of the lip portion 8b caused by the insertion of the piston rod 3 into the inner periphery side, the seal holder 9 can be supported by the inner peripheral portion of the fixing member 32. In addition, since the gap is formed between the fixing member 32 and the seal holder 9 by the provision of the stopper 31, interference between the fixing member 32 and the lip portion 8b of the seal ring 8 can be avoided, and excessive fastening force is not applied to the lip portion 8b, and therefore, deterioration due to abrasion of the seal ring 8 can be suppressed.

[0095] Furthermore, since the fixing member 32 of the stopper 30 has six notches 32a1 on its inner circumference, and the stopper plate 31 has an inner diameter greater than or equal to the diameter of the circumscribed circle C2, the circumscribed circle C2 and the tips of the notches 32a1 are in contact with each other and abut against the seal holder 9. Therefore, even if the seal holder 9 deforms to float away from the seal housing 7 and abuts against the inner circumference of the fixing member 32, the pressure in the expansion-side chamber R1 can still act on the seal holder 9 through the notches 32a1. Therefore, by applying the high pressure within the expansion-side chamber R1, which is compressed during the expansion of the damper D, to the seal holder 9, the tightening force of the lip 8b of the seal ring 8 on the piston rod 3 can be enhanced. Furthermore, even if the seal holder 9 deforms and abuts against the fixing member 32, the pressure in the expansion-side chamber R1 can still act on the lip 8b of the seal ring 8 because the inner diameter of the fixing member 32 is larger than the outer diameter of the piston rod 3. The number of the cutouts 32a1 provided in the main body 32a of the fixing member 32 may be arbitrarily set as long as it is one or more.

[0096] Next, the stopper 40 of the third modified example will be described. Figure 10 and Figure 11 As shown, the stopper 40 of the third variant comprises: a stop plate 41, which is annular, embedded in the inner periphery of the seat 7b and abuts against the sealing bracket 9, and has an inner diameter larger than the outer diameter of the piston rod 3; and a fixing component 42, which is mounted on the seat 7b and fixes the stop plate 41 to the sealing housing 7.

[0097] The stopper plate 41 is annular and fits onto the inner circumference of the retainer 7b. The retainer 7b in the seal housing 7 is annular, with an inner diameter that widens in the middle. It has a stepped portion 7b2 on its inner circumference. In addition, it has an annular groove 7b3 formed circumferentially along the inner circumference of the opening from the stepped portion 7b2, and three longitudinal grooves 7b4 formed axially from the opening end and communicating with the annular groove 7b3.

[0098] The fixing member 42 comprises an annular main body 42a that abuts the guide side of the stopper plate 41; and three protrusions 42b disposed on the outer circumference of the main body 42a at positions corresponding to the longitudinal grooves 7b4. These protrusions are inserted into the longitudinal grooves 7b4 of the retainer 7b and engage with the annular grooves 7b3. The main body 42a comprises six notches 42a1, each with an inner diameter larger than the outer diameter of the piston rod 3, opening from the inner circumference toward the outer circumference. Furthermore, the inner diameter of the stopper plate 41 is greater than or equal to the diameter of a circumscribed circle C4, which is in contact with the tips of the notches 42a1 and is smaller than the outer diameter of the seal holder 9. When the stopper plate 41 is engaged with the inner circumference of the step 7b2 of the retainer 7b, it abuts the guide side of the seal holder 9.

[0099] Further, the outer diameter of the main body portion 42a is larger than the outer diameter of the stopper plate 41 and the smallest diameter among the inner periphery of the seating 7b, and the fixing member 42 is accommodated at a position further to the opening side than the stepped portion 7b2 of the seating 7b. The protrusions 42b of the fixing member 42 are in a shape that matches the longitudinal grooves 7b4 formed on the inner periphery of the seating 7b when the fixing member 42 is viewed in the axial direction, and protrude toward the radial direction from the position on the outer periphery of the main body portion 42a that matches the longitudinal grooves 7b4. Note that the number of protrusions 42b provided on the outer periphery of the main body portion 42a is the same as the number of longitudinal grooves 7b4, but as long as all of the protrusions 42b of the fixing member 42 can be respectively inserted into the longitudinal grooves 7b4 provided in the seating 7b, the number of protrusions 42b can be smaller than or equal to the number of longitudinal grooves 7b4. Further, the diameter of the circumscribed circle C5 that contacts the front end of the protrusion 42b is larger than the inner diameter of the seating 7b, that is, the inner diameter of the stepped portion 7b2, and is smaller than or equal to the inner diameter of the annular groove 7b3.

[0100] Therefore, first, the stopper plate 41 is fitted on the inner periphery of the seating 7b further to the inside than the stepped portion 7b2, and then when the fixing member 42 is inserted into the seating 7b in a state in which each of the protrusions 42b respectively opposes the longitudinal grooves 7b4 of the seating 7b in the axial direction of the seal housing 7 and the fixing member 42, the protrusions 42b are inserted into the longitudinal grooves 7b4, and the fixing member 42 abuts against the stopper plate 41. In this state, the protrusions 42b enter the annular groove 7b3, and therefore, if the fixing member 42 is rotated in the circumferential direction, the protrusions 42b move in the circumferential direction within the annular groove 7b3 and the protrusions 42b do not oppose the longitudinal grooves 7b4, and the fixing member 42 is fixed to the seating 7b. Since the stopper plate 41 abuts against the outer periphery of the guide piece side of the seal holder 9 and is fixed to the seal housing 7, it is possible to prevent the seal ring 8 and the seal holder 9 within the annular recess 7a from falling off the seal housing 7.

[0101] Further, if the axial length, that is, the thickness, of the stopper plate 41 of the stopper 40 of the third modification in the damper D of the present embodiment is set to be larger than or equal to the height of the stepped portion 7b2 of the seating 7b, when the fixing member 42 is installed on the seating 7b, the main body portion 42a of the fixing member 42 is in close contact with the guide piece side of the stopper plate 41, and thus it is possible to fixedly secure the stopper plate 41 to the seal housing 7 without play.

[0102] In the seal member S3 configured in this way, the protrusion 42b is made to enter the annular groove 7b3 provided at the inner periphery of the seating 7b, i.e., at a position further toward the opening side than the stepped portion 7b2, and the fixing member 42 is fixed to the seal housing 7, so the seal member S3 can be easily assembled by hand without using a tool. Further, since the protrusion 42b is made to enter the annular groove 7b3 and the fixing member 42 is fixed to the seal housing 7, the stopper plate 41 can be provided as a thin-walled annular ring, and as with the seal member S1, the axial length of the seal member S3 can be shortened; wherein the annular groove 7b3 is provided at the inner periphery of the seating 7b, i.e., at a position further toward the opening side than the stepped portion 7b2. In addition, since the annular groove 7b3 is formed at a position away from the opening side from the deepest portion of the seating 7b, the annular groove 7b3 can be easily machined.

[0103] The seal member S3 configured in this way, as with the seal members S, S1, S2, after being assembled in advance, is assembled into the piston rod assembly and inserted into the cylinder 1, is clamped and fixed to the cylinder 1 by the rivet 1a and the C-ring 5. Even if vibrations are generated in the seal member S3 in conveying the piston rod assembly, the seal ring 8 and the seal holder 9 can be prevented from falling out of the annular recess 7a of the seal housing 7 by the stopper 40, and the state of the seal ring 8 and the seal holder 9 being housed in the annular recess 7a in the correct posture is maintained.

[0104] Therefore, according to the damper D provided with the seal member S3 configured in this way, since the state of the seal ring 8 and the seal holder 9 being assembled in the correct posture on the seal housing 7 is maintained, the seal ring 8 can be fastened with a uniform fastening force over the entire circumference of the piston rod 3, and stable sealing performance can be exhibited. Further, since the annular groove 7b3 and the longitudinal groove 7b4 communicating with the annular groove 7b3 are provided, and the structure of the protrusion 42b being fitted in the annular groove 7b3 and the fixing member 42 being fixed to the seal housing 7 is adopted, the stopper plate 31 can be provided as a thin-walled annular ring and the axial length of the seal member S3 can be shortened, so according to the damper D provided with the seal member S3, the stroke length can be more easily ensured; wherein the annular groove 7b3 is provided at the inner periphery of the seating 7b, i.e., at a position further toward the opening side than the stepped portion 7b2.

[0105] Further, when the seal member S3 is fixed to the cylinder 1, since the seat 7b is accommodated in the recessed portion 2d of the outer periphery of the guide 2, the main body portion 42a of the fixing member 42 abuts against the convex portion 2c of the guide 2 while being pressed against the seal housing 7 together with the stopper plate 41 by the axial force received from the rivet portion la, and is fixed to the cylinder 1. Since the inner peripheral portion of the main body portion 42a of the fixing member 42 supported by the convex portion 2c of the guide 2 opposes the inner periphery of the seal holder 9, even if the seal holder 9 is deformed in such a manner as to float from the seal housing 7 due to the expansion of the lip portion 8b by the insertion of the inner peripheral side of the piston rod 3, the seal holder 9 can be supported by the inner peripheral portion of the fixing member 42.

[0106] Further, since the fixing member 42 in the stopper 40 has six notches 42al in the inner periphery, the stopper plate 41 has an inner diameter larger than or equal to the diameter of the circumscribed circle C4 which is tangent to the front ends of the notches 42al and abuts against the seal holder 9, even if the seal holder 9 is deformed in such a manner as to float from the seal housing 7 and abuts against the inner periphery of the fixing member 42, the pressure of the extension-side chamber Rl can act on the seal holder 9 via the notches 42al. Therefore, the tightening force of the lip portion 8b of the seal ring 8 against the piston rod 3 can be increased by causing the high pressure in the extension-side chamber Rl compressed when the damper D performs the extension operation to act on the seal holder 9. In addition, even if the seal holder 9 is deformed and abuts against the fixing member 42, since the inner diameter of the fixing member 42 is larger than the outer diameter of the piston rod 3, the pressure of the extension-side chamber Rl can act on the lip portion 8b of the seal ring 8. In addition, the number of the notches 42al provided on the main body portion 42a of the fixing member 42 can be arbitrarily set as long as it is one or more.

[0107] In addition, in the second and third modified examples, the seat 7b of the seal housing 7 can not have the stepped portion 7b2 to make the outer diameter of the stopper plate 31, 41 smaller than the main body portion 32a, 42a of the fixing member 32, 42.

[0108] Further, the stopper can be configured in the following modified examples. As shown in Figure 12 The stopper 50 of the fourth modified example has a stopper plate 51 which is annular, has an inner diameter larger than the outer diameter of the piston rod 3 while abutting against the guide side surface of the seal holder 9 and the seal housing 7, and a fixing member 52 which holds the outer periphery of the seal housing 7 and fixes the stopper plate 51 to the seal housing 7.

[0109] As shown in Figure 12 The seal housing 7 is in a shape in which the seat 7b in the seal housing 7 shown in Figure 6 The seal housing 7 is in a shape in which the seat 7b in the seal housing 7 shown in Figure 12On the inner periphery of the lower end of the guide member 2 side end; the outer diameter small diameter portion 7e, which will serve as the guide member side end Figure 12 The outer periphery of the lower end is set to a small diameter; and an annular recess 7c, which is provided as a Figure 12 On the opposite side of the upper guide Figure 12 On the outer periphery of the upper end.

[0110] The stopper plate 51 is annular and has an inner diameter smaller than the outer diameter of the seal holder 9 and an outer diameter larger than the outer diameter of the seal holder 9 and smaller than the outer diameter of the guide-side end of the seal housing 7 .

[0111] The fixing member 52 has Figure 6 The fixing member 22 of the first modified example shown has a substantially similar structure, comprising: an annular main body 52a facing the guide side of the stopper plate 51; and six clamping arms 52b disposed on the outer periphery of the main body 52a to grip the outer periphery of the smaller outer diameter portion 7e of the seal housing 7. Furthermore, the main body 52a includes six notches 52a1, each having an inner diameter larger than the outer diameter of the piston rod 3 and opening from the inner periphery toward the outer periphery. Furthermore, the clamping arms 52b of the fixing member 52 have curved tips, forming a hook-shaped claw when viewed from the side. When engaged with the outer periphery of the smaller outer diameter portion 7e, they secure the smaller outer diameter portion 7e and grip the seal housing 7.

[0112] In addition, the inner diameter of the stop plate 51 is greater than or equal to the diameter of the circumscribed circle where the front ends of the cutouts 52a1 meet each other and is smaller than the outer diameter of the sealing bracket 9. The outer diameter of the stop plate 51 is set to fit with the inner surface of the clamping arm 52b of the fixing member 52. In addition, in the stopper 50 of this embodiment, there is a gasket 53 clamped between the stop plate 51 and the fixing member 52. The gasket 53 has an inner diameter that is substantially equal to the inner diameter of the stop plate 51. In addition, the outer diameter of the gasket 53 is smaller than the outer diameter of the stop plate 50. Furthermore, the diameter from the front end of the clamping arm 52b to the main body 52a is smaller than the outer diameter of the stop plate 50. Figure 12 The length in the vertical direction is longer than the axial length when the laminate is stacked on the stopper plate 51 and the washer 53 .

[0113] Therefore, after overlapping the stop plate 51 on the base 9a of the sealing bracket 9 and the sealing housing 7 and overlapping the gasket 53 on the guide side of the stop plate 51, when the outer periphery of the small diameter outer diameter portion 7d is grasped by the clamping arm 52b and the fixing component 52 is installed on the sealing housing 7, the sealing ring 8, the sealing bracket 9, the stop plate 51 and the gasket 53 are clamped and fixed by the fixing component 52 and the sealing housing 7.

[0114] Further, since the stopper plate 51 is fitted to the inner surface of the clamp arm 52b of the fixing member 52, the stopper plate 51 is centered by the fixing member 52 and fixed to the seal housing 7. The outer diameter of the gasket 53 is set to the extent that it does not come into contact with the inner surface of the clamp arm 52b, so the bending portion of the boundary between the main body portion 52a and the clamp arm 52b of the fixing member 52 can be avoided, and the main body portion 52a of the fixing member 52 can be brought into abutment with the gasket 53 without being lifted, and the seal ring 8, the seal holder 9, the stopper plate 51, and the gasket 53 can be securely fixed to the seal housing 7. The gasket 53 is installed so that the main body portion 52a of the fixing member 52 is brought into abutment with the convex portion 2c of the guide 2 and receives the axial force from the rivet portion la with respect to the seal housing 7 when the seal member S4 is fixed to the cylinder 1, but can be omitted when the stopper plate 51 and the fixing member 52 can sufficiently receive the axial force.

[0115] Further, as described above, when the fixing member 52 is installed to the seal housing 7 in the state that the stopper plate 51 is laminated to the seal housing 7, the stopper plate 51 is fixed to the seal housing 7. Since the stopper plate 51 is brought into abutment with the outer peripheral side of the guide side surface of the seal holder 9 and fixed to the seal housing 7, the seal ring 8 and the seal holder 9 in the annular recessed portion 7a can be prevented from falling off from the seal housing 7.

[0116] Further, in the stopper 50 of the fourth modified example of the damper D of the present embodiment, the seating 7b is not provided to the seal housing 7, but the fixing member 52 holds the outer periphery of the seal housing 7 to fix it to the seal housing 7, so the stopper plate 51 can be held by the fixing member 52 and the seal housing 7, and the stopper plate 51 can be fixed to the seal housing 7 without play by being in close contact with the guide side surface of the seal housing 7.

[0117] In the seal member S4 configured in this way, since the outer periphery of the seal housing 7 is held and the fixing member 52 is fixed to the seal housing 7, the seal member S4 can be easily assembled by hand without using tools by reducing the tightening force of the clamp arm 52b. Further, since the outer periphery of the seal housing 7 is held and the fixing member 52 is fixed to the seal housing 7, the stopper plate 51 can be configured as a thin-walled circular ring, and the axial length of the seal member S4 can be shortened.

[0118] The seal member S4 configured in this way, like the seal member S, after being assembled in advance, is assembled into the piston rod assembly and inserted into the cylinder 1, and is held and fixed to the cylinder 1 by the rivet portion la and the C-ring 5. Even when the piston rod assembly is assembled or when it is inserted into the cylinder 1, the seal ring 8 and the seal holder 9 can be prevented from falling off from the annular recessed portion 7a of the seal housing 7 by the stopper 50, and the state that the seal ring 8 and the seal holder 9 are housed in the annular recessed portion 7a in the correct posture can be maintained.

[0119] Therefore, according to the shock absorber D including the sealing member S4 constructed in this manner, since the seal ring 8 and the seal holder 9 are maintained in the correct assembled state on the seal housing 7, the seal ring 8 can be tightened with uniform tightening force over the entire circumference of the piston rod 3, thereby achieving stable sealing performance. Furthermore, since the fixing member 52 is fixed to the seal housing 7 by gripping the outer circumference of the seal housing 7, the stopper plate 51 can be formed into a thin-walled ring, and the axial length of the sealing member S4 can be shortened. Therefore, according to the shock absorber D including the sealing member S4, it is easier to ensure the stroke length.

[0120] Furthermore, when the seal member S4 is secured to the cylinder 1, the main body 52a of the fixing member 52 abuts the protrusion 2c of the guide 2. Using the axial force applied from the rivet 1a, the fixing member 52, along with the stopper plate 51, presses the seal housing 7 against the cylinder 1, securing the seal member S4. Since the inner periphery of the main body 52a of the fixing member 52, supported by the protrusion 2c of the guide 2, faces the inner periphery of the seal holder 9, the inner periphery of the fixing member 52 supports the seal holder 9 even if the lip 8b expands in diameter due to insertion into the inner periphery of the piston rod 3, causing the seal holder 9 to lift from the seal housing 7. Furthermore, the provision of the stopper plate 51 creates a gap between the fixing member 52 and the seal holder 9, thereby preventing interference between the fixing member 52 and the lip 8b of the seal ring 8. This prevents excessive tightening force from being applied to the lip 8b, thereby suppressing deterioration of the seal ring 8 due to wear.

[0121] Furthermore, since the fixing member 52 of the stopper 50 has six notches 52a1 on its inner circumference, and the stopper plate 51 has an inner diameter greater than or equal to the diameter of the circumscribed circle, the circumscribed circle and the tips of the notches 52a1 are in contact with each other and abut against the seal holder 9. Therefore, even if the seal holder 9 deforms to float away from the seal housing 7 and abuts against the inner circumference of the fixing member 52, the pressure in the expansion-side chamber R1 can still act on the seal holder 9 through the notches 52a1. Therefore, by applying the high pressure within the expansion-side chamber R1, which is compressed during the expansion of the damper D, to the seal holder 9, the tightening force of the lip 8b of the seal ring 8 on the piston rod 3 can be enhanced. Furthermore, even if the seal holder 9 deforms and abuts against the fixing member 52, the pressure in the expansion-side chamber R1 can still act on the lip 8b of the seal ring 8 because the inner diameter of the fixing member 52 is larger than the outer diameter of the piston rod 3. The number of the cutouts 52a1 provided in the main body 52a of the fixing member 52 may be arbitrarily set as long as it is one or more.

[0122] While the preferred embodiments of the present invention have been described in detail above, modifications, variations, and alterations may be made without departing from the scope of the claims.

[0123] This application claims priority based on Japanese Patent Application No. 2021-001804 filed on January 8, 2021 with the Japan Patent Office, the entire contents of which are incorporated by reference herein.

Claims

1. A buffer comprising: a cylinder; an annular guide member fitted on the inner circumference of the end portion of the cylinder; a piston rod inserted through the inner periphery of the guide and movably inserted into the cylinder; a piston connected to the piston rod and inserted into the cylinder to divide the cylinder into an extension-side chamber and a compression-side chamber filled with a working fluid; and a sealing member having an annular shape and laminated on the opposite side of the guide from the piston, fitted into the inner periphery of the end portion of the cylinder, with the piston rod inserted through the inner periphery of the sealing member; The sealing component has: an annular sealing housing having an annular recess on an inner periphery on a guide side; a sealing ring including an annular base portion and an annular lip portion rising from the inner periphery of the base portion toward the guide member and in sliding contact with the outer periphery of the piston rod, and housed in the annular recess; an annular seal support that is stacked on the guide side of the base portion of the seal ring and housed in the annular recess, thereby supporting the outer periphery of the lip portion and suppressing the expansion of the lip portion; The stopper is sandwiched between the guide and the sealing housing, installed on the sealing housing and abutted against the guide side of the sealing bracket to prevent the sealing bracket and the sealing ring from falling off.

2. The buffer according to claim 1, wherein The sealing housing has an annular seat on the outer periphery of the guide member side. The stopper includes: a stop plate which is annular, is fitted on the inner periphery of the seat and abuts against the sealing bracket, and has an inner diameter larger than the outer diameter of the piston rod; and a fixing component which is mounted on the seat and fixes the stop plate to the sealing housing.

3. The buffer according to claim 2, wherein The stop plate has: an inner peripheral portion, which is opposite to the sealing support and forms an annular gap between the inner peripheral portion and the sealing support; An outer peripheral portion connected to the outer periphery of the inner peripheral portion and abutting against the sealing bracket while being embedded in the inner periphery of the seat; One or more through holes extending through the inner periphery; and a chamfered portion provided on an outer periphery of the guide member side of the outer peripheral portion. The buffer according to claim 1 , wherein: The guide is in contact with the stopper while being away from the sealing housing.

5. A buffer comprising: cylinder; an annular guide member fitted on the inner circumference of the end portion of the cylinder; a piston rod inserted through the inner periphery of the guide and movably inserted into the cylinder; a piston connected to the piston rod and inserted into the cylinder to divide the cylinder into an extension-side chamber and a compression-side chamber filled with a working fluid; and a sealing member having an annular shape and laminated on the opposite side of the guide from the piston, fitted into the inner periphery of the end portion of the cylinder, with the piston rod inserted through the inner periphery of the sealing member; The sealing component has: An annular sealing housing having an annular recess on the inner periphery of the guide side and an annular recess on the outer periphery of the guide side There is an annular seat on it; a sealing ring including an annular base portion and an annular lip portion rising from the inner periphery of the base portion toward the guide member and in sliding contact with the outer periphery of the piston rod, and housed in the annular recess; an annular seal support that is stacked on the guide side of the base portion of the seal ring and housed in the annular recess, thereby supporting the outer periphery of the lip portion and suppressing the expansion of the lip portion; A stopper is mounted on the sealing housing and abuts against the side of the guide member of the sealing bracket to prevent the sealing bracket and the sealing ring from falling off: The stopper comprises: a stopper plate, which is annular and is fitted on the inner periphery of the seat and abuts against the sealing bracket, and has an inner diameter larger than the outer diameter of the piston rod; and a fixing member, which is mounted on the seat and fixes the stopper plate to the sealing housing. The fixing component has: a main body portion, which is annular and abuts against a side surface of the guide member of the stop plate; and three or more clamping arms, which are arranged on the outer periphery of the main body and grip the outer periphery of the seat; The main body has one or more cutouts with an inner diameter larger than the outer diameter of the piston rod and opening from the inner periphery toward the outer periphery. The stopper plate has an inner diameter greater than or equal to a diameter of a circumscribed circle, and the circumscribed circle and a front end of the cutout are in contact with each other.

6. A buffer comprising: cylinder; an annular guide member fitted on the inner circumference of the end portion of the cylinder; a piston rod inserted through the inner periphery of the guide and movably inserted into the cylinder; a piston connected to the piston rod and inserted into the cylinder to divide the cylinder into an extension-side chamber and a compression-side chamber filled with a working fluid; and a sealing member having an annular shape and laminated on the opposite side of the guide from the piston, fitted into the inner periphery of the end portion of the cylinder, with the piston rod inserted through the inner periphery of the sealing member; The sealing component has: An annular sealing housing having an annular recess on the inner periphery of the guide side and an annular recess on the outer periphery of the guide side There is an annular seat on it; a sealing ring including an annular base portion and an annular lip portion rising from the inner periphery of the base portion toward the guide member and in sliding contact with the outer periphery of the piston rod, and housed in the annular recess; an annular seal support that is stacked on the guide side of the base portion of the seal ring and housed in the annular recess, thereby supporting the outer periphery of the lip portion and suppressing the expansion of the lip portion; A stopper is mounted on the sealing housing and abuts against the side of the guide member of the sealing bracket to prevent the sealing bracket and the sealing ring from falling off: The stopper comprises: a stopper plate, which is annular and is fitted on the inner periphery of the seat and abuts against the sealing bracket, and has an inner diameter larger than the outer diameter of the piston rod; and a fixing member, which is mounted on the seat and fixes the stopper plate to the sealing housing. The seat has a large diameter portion on its inner periphery that is larger than the inner diameter of the opening end, and the fixing component has: a main body portion, which is annular and abuts against a side surface of the guide member of the stop plate; and a plurality of jaws provided on the outer periphery of the main body portion and entering into the large diameter portion of the socket; The main body has one or more cutouts with an inner diameter larger than the outer diameter of the piston rod and opening from the inner periphery toward the outer periphery. The stopper plate has an inner diameter greater than or equal to a diameter of a circumscribed circle, and the circumscribed circle and a front end of the cutout are in contact with each other.

7. A buffer comprising: cylinder; an annular guide member fitted on the inner circumference of the end portion of the cylinder; a piston rod inserted through the inner periphery of the guide and movably inserted into the cylinder; a piston connected to the piston rod and inserted into the cylinder to divide the cylinder into an extension-side chamber and a compression-side chamber filled with a working fluid; and a sealing member having an annular shape and laminated on the opposite side of the guide from the piston, fitted into the inner periphery of the end portion of the cylinder, with the piston rod inserted through the inner periphery of the sealing member; The sealing component has: an annular sealing housing having an annular recess on an inner periphery on a guide side and an annular seat on an outer periphery on a guide side; a sealing ring including an annular base portion and an annular lip portion rising from the inner periphery of the base portion toward the guide member and in sliding contact with the outer periphery of the piston rod, and housed in the annular recess; an annular seal support that is stacked on the guide side of the base portion of the seal ring and housed in the annular recess, thereby supporting the outer periphery of the lip portion and suppressing the expansion of the lip portion; A stopper is mounted on the sealing housing and abuts against the side of the guide member of the sealing bracket to prevent the sealing bracket and the sealing ring from falling off: The stopper comprises: a stopper plate, which is annular and is fitted on the inner periphery of the seat and abuts against the sealing bracket, and has an inner diameter larger than the outer diameter of the piston rod; and a fixing member, which is mounted on the seat and fixes the stopper plate to the sealing housing. The retainer has an annular groove provided on the inner periphery, and one or more longitudinal grooves formed on the inner periphery along the axial direction from the opening end and communicating with the annular groove. The fixing component comprises: a main body portion, which is annular and abuts against a side surface of the guide member of the stop plate; and one or more protrusions, which are provided at positions on the outer periphery of the main body that coincide with the longitudinal grooves and can be inserted into the longitudinal grooves of the seat and fit into the annular grooves; The main body has a plurality of cutouts with an inner diameter larger than the outer diameter of the piston rod and opening from the inner periphery toward the outer periphery. The stopper plate has an inner diameter greater than or equal to a diameter of a circumscribed circle, and the circumscribed circle and a front end of the cutout are in contact with each other.

8. A buffer comprising: cylinder; an annular guide member fitted on the inner circumference of the end portion of the cylinder; a piston rod inserted through the inner periphery of the guide and movably inserted into the cylinder; a piston connected to the piston rod and inserted into the cylinder to divide the cylinder into an extension-side chamber and a compression-side chamber filled with a working fluid; and a sealing member having an annular shape and laminated on the opposite side of the guide from the piston, fitted into the inner periphery of the end portion of the cylinder, with the piston rod inserted through the inner periphery of the sealing member; The sealing component has: an annular sealing housing having an annular recess on an inner periphery on a guide side; a sealing ring including an annular base portion and an annular lip portion rising from the inner periphery of the base portion toward the guide member and in sliding contact with the outer periphery of the piston rod, and housed in the annular recess; an annular seal support that is stacked on the guide side of the base portion of the seal ring and housed in the annular recess, thereby supporting the outer periphery of the lip portion and suppressing the expansion of the lip portion; A stopper is mounted on the sealing housing and abuts against the side of the guide member of the sealing bracket to prevent the sealing bracket and the sealing ring from falling off: The stopper has a stop plate which is annular and connected to the guide side of the sealing bracket and the The sealing housings are in contact with each other, and the inner diameter thereof is larger than the outer diameter of the piston rod; and a fixing member that holds the outer periphery of the sealing housing and fixes the stopper plate to the sealing housing.

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