Shock absorber

Abstract

To provide a shock absorber which can increase a pull-out load.SOLUTION: A shock absorber includes: a rod which holds a piston part at first side end; a cylinder which houses the first side end of the rod and exposes a second side end of the rod and stores liquid therein; a seal member which is provided between the rod and the cylinder to seal the inside of the cylinder; and a cap attached to the second side end of the cylinder. The cylinder has a folded part which is folded inward and inhibits the seal member from moving to the second side. Further, the cylinder is formed with a recessed part recessed from an outer peripheral surface. The cap has: a ring-like annular part provided at the second side of the folded part; and a facing part protruding to the first side from the annular part and facing the outer peripheral surface. The facing part has a bent part which is attached to the second side end of the cylinder and then bent inward to fit in the recessed part.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] For example, the hydraulic shock absorber described in Patent Document 1 includes a cylindrical cylinder that is roll-formed from its outer periphery to form the shape of the inner or outer diameter portion of one end. The hydraulic shock absorber described in Patent Document 1 also includes a circumferentially extending recess formed on the outer periphery of one end of the cylinder during the roll-forming process, and a piston rod that protrudes from one end of the cylinder. The hydraulic shock absorber described in Patent Document 1 also includes a sealing means that is provided at one end of the cylinder and through which the piston rod passes. The hydraulic shock absorber described in Patent Document 1 also includes a covered, cylindrical bumper cap that is fitted to one end of the cylinder and has circumferentially extending or scattered protrusions on the inner circumferential surface of the cylinder that engage with the recesses. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-14018 Summary of the Invention [Problem to be solved by the invention]

[0004] In the hydraulic shock absorber described in Patent Document 1, a crimped portion formed by crimping one end of the cylinder inward prevents the rod (piston rod in Patent Document 1) from coming out of the cylinder during the extension stroke. Therefore, the magnitude of the load (in other words, the coming out load) applied to the rod when it comes out of the cylinder during the extension stroke is determined by the plate thickness and shape of the crimped portion of the cylinder.

[0005] On the other hand, as vehicle weight increases due to factors such as larger vehicles, there is a demand for a larger pull-out load. To increase the pull-out load, it is possible to increase the plate thickness of the crimped part of the cylinder or change its shape, but both of these require changes to the equipment used for crimping. An object of the present invention is to provide a shock absorber that can increase the withdrawal load. [Means for solving the problem]

[0006] The present invention, which was completed with this object in mind, is a shock absorber comprising: a rod that holds a piston portion at a first end; a cylinder that accommodates the first end of the rod and exposes the second end of the rod, and that is filled with liquid; a sealing member that is provided between the rod and the cylinder and seals the inside of the cylinder; and a cap that is attached to the second end of the cylinder, wherein the cylinder has a bent portion that is bent inward to prevent the sealing member from moving toward the second side, and the cylinder has a recess that is recessed from its outer surface, and the cap has an annular portion that is provided on the second side of the bent portion, and an opposing portion that protrudes from the annular portion to the first side and faces the outer surface, and the opposing portion has a bent portion that is placed over the second end of the cylinder and then bent inward to fit into the recess. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a shock absorber that can increase the withdrawal load. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a diagram showing a schematic configuration of a suspension device. [Figure 2] FIG. 2 is an example of an enlarged view of part II in FIG. 1. [Figure 3] FIG. 3 is an example of an enlarged view of part III in FIG. 2. [Figure 4] 10A and 10B are diagrams showing an example of a shape of a bump stopper before being connected to an outer cylinder. [Figure 5] FIG. 10 is a diagram showing an example of a cross section of a bump stopper according to a second embodiment. [Figure 6] FIG. 10 is an example of a perspective view of a bump stopper according to a second embodiment. [Figure 7] 10 is a diagram showing an example of a shape of a bump stopper according to a second embodiment before being connected to an outer cylinder. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First Embodiment FIG. 1 is a diagram showing an example of a schematic configuration of a suspension device 1. As shown in FIG. FIG. 2 is an example of an enlarged view of part II in FIG. The suspension 1 is a strut-type suspension, and as shown in FIG. 1 , includes a hydraulic shock absorber 2 and a coil spring 3 disposed outside the shock absorber 2. The suspension 1 also includes a lower spring seat 4 that supports one axial end (lower side in FIG. 1 ) of a rod 20 (described later) of the coil spring 3. Hereinafter, the axial direction of the rod 20 (described later) may be simply referred to as the "axial direction." The suspension 1 also includes an upper spring seat 5 that supports the other axial end (upper side in FIG. 1 ) of the coil spring 3. Hereinafter, the "one axial end" may be simply referred to as the "first side," and the "other axial end" may be simply referred to as the "second side." A direction intersecting the axial direction (e.g., a perpendicular direction) may be simply referred to as the "radial direction." In the radial direction, the side toward the centerline of an outer cylinder 11 (described later) may be simply referred to as the "inner side," and the side away from the centerline may be simply referred to as the "outer side."

[0010] The suspension 1 is provided with a vehicle body side mounting bracket 6 that is attached to the second end for mounting the suspension 1 to a vehicle, and a wheel side mounting bracket 7 that is fixed to the first end of a cylinder portion 10 (described later) for mounting the suspension 1 to a wheel. The suspension 1 also includes a bump cushion 8 that is attached to the vehicle body side mounting bracket 6 and that absorbs the impact when a rod 20 (described later) compresses.

[0011] (buffer 2) The shock absorber 2 will be described in detail below. As shown in FIG. 1 , the shock absorber 2 is a twin-cylinder shock absorber. The shock absorber 2 includes a cylinder portion 10 that contains oil, and a rod 20 whose second end protrudes from the cylinder portion 10 and whose first end is inserted into the cylinder portion 10. The shock absorber 2 also includes a piston portion 30 that is provided at the first end of the rod 20, and a bottom portion 40 that is provided at the first end of the cylinder portion 10. The shock absorber 2 also includes a rebound seat 25 that is fixed to the rod 20, and a rebound rubber 26 that is an annular elastic member that is arranged on the second side of the rebound seat 25, in order to absorb the impact when the rod 20 extends. The shock absorber 2 also includes a bump stopper 50 that is attached to the second end of the cylinder portion 10, and an annular ring 69 that has a circular cross section that is provided between the cylinder portion 10 and the bump stopper 50.

[0012] [Cylinder section 10] The cylinder portion 10 includes a thin-walled cylindrical outer cylinder 11 and a thin-walled cylindrical inner cylinder 12 housed within the outer cylinder 11 . The outer cylinder 11 has two portions with different thicknesses: a first portion 111 that is thicker and provided on the first side, and a second portion 112 that is thinner and provided on the second side of the first portion 111. The outer diameters of the first portion 111 and the second portion 112 are the same, and the inner diameter of the second portion 112 is larger than the inner diameter of the first portion 111.

[0013] A recess 114 recessed inward from the outer circumferential surface 113 is formed around the entire circumference at the end of the second side of the first part 111. The cross-sectional shape of the recess 114 cut along a plane parallel to the axial direction is a rectangle with the axial direction as the longitudinal direction and the radial direction as the lateral direction. However, the shape of the end of the second side of the recess 114 is, for example, an arc shape, and the radius of the arc is the same as the radius of the ring 69. The outer cylinder 11 has a bent portion 15 formed by bending the second end of the second portion 112 inward, that is, by applying so-called roll caulking.

[0014] The cylinder portion 10 also includes a bottom cover 13 that closes the first end of the outer cylinder 11. The cylinder portion 10 defines a reservoir chamber R with the outer peripheral surface of the inner cylinder 12 and the inner peripheral surface of the outer cylinder 11. The outer cylinder 11 is filled with oil, which is an example of a fluid. The outer cylinder 11 may also be filled with a liquid such as water, or a gas such as air.

[0015] The cylinder section 10 includes a rod guide section 70 that is disposed inside the outer cylinder 11, blocks the second end of the inner cylinder 12, and movably (in other words, slidably) supports the rod 20. The cylinder section 10 also includes an oil seal 80 that is provided on the second side of the rod guide section 70 and prevents oil from leaking from the outer cylinder 11 and foreign matter from entering the outer cylinder 11, and a collar 90 that is provided on the second side of the oil seal 80.

[0016] [Rod 20] The rod 20 is a solid or hollow rod-shaped member, and has a columnar or cylindrical rod portion 21. The rod 20 also has a first-side mounting portion 22 for mounting the piston portion 30 at its first end, and a second-side mounting portion 23 for mounting the vehicle body-side mounting bracket 6 at its second end. Male threads are formed at the ends of the first-side mounting portion 22 and the second-side mounting portion 23. The rod 20 is arranged so that the axial direction of the rod 20 coincides with the direction of the center line of the outer cylinder 11 and the inner cylinder 12 , and moves along the direction of the center line of the outer cylinder 11 and the inner cylinder 12 . A rebound seat 25 is fixed to the first end of the rod 20 .

[0017] [Piston portion 30] The piston section 30 includes a piston 31, a first side valve group 32 that blocks first side ends of some of the oil passages formed in the piston 31, and a second side valve group 33 that blocks second side ends of some of the oil passages formed in the piston 31.

[0018] [Bottom part 40] The bottom portion 40 includes a valve body 41 having a plurality of oil passages passing through in the axial direction, a first side valve 42 provided on a first side of the valve body 41, and a second side valve 43 provided on a second side of the valve body 41. The valve body 41 of the bottom portion 40 separates the oil chamber and the reservoir chamber R in the inner cylinder 12 .

[0019] [Rod guide part 70] The rod guide portion 70 includes a thin-walled cylindrical guide 71 disposed inside, and a guide case 72 that holds the guide 71 inside. The inner diameter of the guide 71 is set slightly larger than the outer diameter of the rod portion 21 of the rod 20 inserted inside. The inner peripheral surface of the guide 71 comes into contact with the outer peripheral surface of the rod 20, so the guide 71 is made of a material that is more wear-resistant than the guide case 72.

[0020] Guide case 72 has a cylindrical inner cylindrical portion 73 provided on the inside, and a cylindrical outer cylindrical portion 74 provided on the outside of inner cylindrical portion 73. It is preferable that inner cylindrical portion 73 and outer cylindrical portion 74 are integrally molded so that the outer peripheral surface of a portion of inner cylindrical portion 73 on the second axial side and the inner peripheral surface of outer cylindrical portion 74 on the first axial side are joined together.

[0021] A guide 71 is fitted inside the inner cylindrical portion 73 . The outer cylindrical portion 74 is disposed on the second side of the inner cylinder 12, between the rod 20 and the outer cylinder 11. The outer diameter of the outer cylindrical portion 74 is larger than the inner diameter of the first portion 111 of the outer cylinder 11 and smaller than the inner diameter of the second portion 112. The outer cylindrical portion 74 has an inner recess 76 recessed from the upper end surface 75 on the inside of the upper end, and an outer recess 77 recessed from the upper end surface 75 on the outside of the upper end. The guide case 72 may be made of, for example, a metal such as steel or a non-metallic material such as polytetrafluoroethylene.

[0022] [Oil seal 80] The oil seal 80 has a base 81 made of metal such as steel, and an elastic portion 82 made of a material with a low elastic modulus such as synthetic rubber. The oil seal 80 is formed by, for example, baking and bonding the elastic portion 82 to the base 81, and the base 81 holds the elastic portion 82. The oil seal 80 is disposed on the second side of the rod guide portion 70, and is held to the outer cylinder 11 via a collar 90 by bending the second side end of the outer cylinder 11 inward, i.e., by so-called roll caulking.

[0023] The base 81 may be, for example, a thin circular ring having an outer diameter larger than the inner diameter of the first portion 111 of the outer cylinder 11 and smaller than the inner diameter of the second portion 112.

[0024] The elastic portion 82 is provided on the first side of the base 81, has a wedge-shaped cross section, and has a seal lip portion 821 that is pressed by an annular spring and comes into close contact with the entire outer circumferential surface of the rod 20. The elastic portion 82 also has a dust lip 822 that is provided on the second side of the base 81 and comes into close contact with the entire outer circumferential surface of the rod 20, thereby preventing dust from entering from outside.

[0025] The elastic part 82 also has an outer circumferential seal part 823 that protrudes from the outer periphery of the base 81 around the entire circumference in a direction inclined downward and outward in the axial direction. The outer circumferential seal part 823 is located in the outer recess 77 of the guide case 72 of the rod guide part 70 and comes into contact with the inner circumferential surface of the outer cylinder 11, thereby preventing oil from leaking from the gap between the outer circumferential surface of the guide case 72 and the inner circumferential surface of the outer cylinder 11.

[0026] The elastic portion 82 also has a central seal portion 824 that protrudes from the inner periphery of the base 81 around the entire circumference in a direction inclined downward and outward in the axial direction. The central seal portion 824 comes into contact with the lower corner of the inner recess 76 of the outer cylindrical portion 74 of the guide case 72, thereby preventing oil from flowing toward the upper end surface 75 of the outer cylindrical portion 74.

[0027] [Color 90] The collar 90 is a thin, annular member. The inner diameter of the collar 90 is larger than the outer diameter of the dust lip 822 of the elastic portion 82 of the oil seal 80. The outer diameter of the collar 90 is larger than the inner diameter of the first portion 111 of the outer cylinder 11 and smaller than the inner diameter of the second portion 112. In addition, the outer diameter of the collar 90 may be larger than the outer diameter of the base 81 of the oil seal 80. The thickness of the collar 90 is determined so that a stopper 51 (described later) of the bump stopper 50 is located on the second side of the dust lip 822 of the oil seal 80.

[0028] [Bump stopper 50] The bump stopper 50 includes a cap 60 that covers the periphery of the outer peripheral surface 113 of the outer cylinder 11, and a stopper 51 that stops the movement of the bump cushion 8. The cap 60 and the stopper 51 may be formed from metal, for example. The thickness of the cap 60 may be equal to or less than the thickness of the second portion 112 of the outer cylinder 11, and the thickness of the stopper 51 may be greater than the thickness of the second portion 112 of the outer cylinder 11.

[0029] The cap 60 has an annular portion 61 provided on the second side of the bent portion 15 of the outer cylinder 11, and an opposing portion 62 that protrudes from the outer periphery of the annular portion 61 to the first side and faces the outer circumferential surface 113 of the outer cylinder 11. The annular portion 61 and the opposing portion 62 are connected by a bend R so as to fit along the outer shape of the outer cylinder 11.

[0030] The annular portion 61 is flat and protrudes inward from the entire second end of the opposing portion 62. The annular portion 61 has a hole 63 formed therein through which a dust lip 822 of an oil seal 80 provided around the rod 20 can pass.

[0031] The facing portion 62 is generally cylindrical. The inner diameter of the facing portion 62 is equal to or smaller than the outer diameter of the outer cylinder 11. The facing portion 62 of the cap 60 is fitted tightly onto the outside of the outer cylinder 11 (in other words, press-fitted). However, the facing portion 62 does not have to be fitted tightly onto the outer cylinder 11. The shape of the first end of the facing portion 62 will be described in detail later.

[0032] The stopper 51 is a circular, flat member. The inner diameter of the stopper 51 is larger than the outer diameter of the rod portion 21 of the rod 20 and smaller than the diameter of the hole 63 of the annular portion 61 of the cap 60. The outer diameter of the stopper 51 can be, for example, the same as the outer diameter of the opposing portion 62 of the cap 60.

[0033] The stopper 51 and the annular portion 61 of the cap 60 are joined by projection welding. Therefore, the bump stopper 50 has a joint portion 53 formed by projection welding. A plurality of (for example, four) joint portions 53 are provided in the circumferential direction.

[0034] Next, the shape of the end portion on the first side of the facing portion 62 will be described in detail. FIG. 3 is an example of an enlarged view of part III in FIG. FIG. 4 is a diagram showing an example of the shape of the bump stopper 50 before it is connected to the outer cylinder 11. As shown in FIG. The opposing portion 62 of the cap 60 is cylindrical before being attached to the cylinder portion 10, and a groove 64 recessed from the inner peripheral surface to the outside is formed around the entire circumference of the opposing portion 62. The cross section of the groove 64 cut along a plane parallel to the axial direction is an arc shape, and the radius of the arc is the same as the radius of the ring 69, for example.

[0035] Furthermore, the facing portion 62 has an inclined surface 65 formed on the inner circumferential surface at the end on the first side, the inclined surface 65 being formed so that the inner diameter gradually increases from the second side to the first side. Then, as shown in FIG. 4, the cap 60 is placed on the outer cylinder 11 so that the ring 69 is fitted between the recess 114 of the first part 111 of the outer cylinder 11 and the groove 64 . Thereafter, the facing portion 62 is bent inward at a portion on the first side of the groove 64, and the end portion on the first side is fitted into the recess 114 of the outer cylinder 11. The portion on the first side of the groove 64 is bent inward so as to encase the ring 69. As a result, as shown in FIG. 3 , the cap 60 has a bent portion 66 in which the portion on the first side of the groove 64 is bent inward and fitted into the recess 114 of the outer cylinder 11.

[0036] The shock absorber 2 configured as above is assembled as follows. The bottom part 40 is inserted into the outer cylinder 11 which is integrated with the bottom cover 13, and the inner cylinder 12 is then inserted. After that, the rod 20 to which the piston part 30 and the rebound seat 25 are attached is inserted into the inner cylinder 12 from the piston part 30 side, and the rebound rubber 26 is inserted into the inner cylinder 12.

[0037] Thereafter, the rod guide portion 70 is inserted into the outer cylinder 11. At that time, the inner cylindrical portion 73 of the guide case 72 of the rod guide portion 70 is inserted into the inner cylinder 12, and the first side surface of the outer cylindrical portion 74 is brought into contact with the second side surface of the inner cylinder 12. The inner cylinder 12 is prevented from moving in the axial direction by the valve body 41 of the bottom portion 40 and the outer cylindrical portion 74 of the guide case 72 of the rod guide portion 70. Furthermore, the inner cylinder 12 is prevented from moving in the radial direction by the valve body 41 of the bottom portion 40 and the inner cylindrical portion 73 of the guide case 72.

[0038] After inserting the rod guide portion 70 into the outer cylinder 11, the oil seal 80 is inserted into the outer cylinder 11 until the first side surface of the base 81 of the oil seal 80 contacts the upper end surface 75 of the outer cylindrical portion 74 of the guide case 72. In addition, the collar 90 is inserted into the second side of the oil seal 80.

[0039] After the oil seal 80 and the collar 90 are inserted into the outer cylinder 11, the second end of the outer cylinder 11 is bent inward by, for example, roll caulking. At this time, the second end of the outer cylinder 11 is bent until it contacts the second surface of the collar 90, forming a bent portion 15. Then, the bump stopper 50 is connected to the outer cylinder 11 as described above.

[0040] As described above, the shock absorber 2 includes the rod 20 that holds the piston portion 30 at its first end, and the outer cylinder 11 (an example of a cylinder) that houses the first end of the rod 20 and exposes the second end of the rod 20, and that is filled with oil. The shock absorber 2 also includes the oil seal 80 (an example of a sealing member) that is provided between the rod 20 and the outer cylinder 11 to seal the inside of the outer cylinder 11, and the cap 60 that is attached to the second end of the outer cylinder 11. The outer cylinder 11 has a bent portion 15 that is bent inward to prevent the oil seal 80 from moving toward the second side, and the outer cylinder 11 has a recess 114 that is recessed from its outer peripheral surface. The cap 60 has an annular portion 61 that is provided on the second side of the bent portion 15, and a facing portion 62 that protrudes from the annular portion 61 toward the first side and faces the outer peripheral surface 113. The facing portion 62 has a bent portion 66 that is bent inward and fitted into the recess 114 after being placed over the second end of the outer cylinder 11 .

[0041] In the shock absorber 2 configured as described above, the rod 20 is unlikely to come off from the outer cylinder 11. That is, because the bent portion 66 of the cap 60 fits into the recess 114 of the outer cylinder 11, the cap 60 is unlikely to fall off from the outer cylinder 11. Therefore, even if the rod 20 is pulled in the direction of the second side, the piston portion 30 held by the rod 20 is prevented from moving in the direction of the second side, and the rod 20 is prevented from coming off from the outer cylinder 11. In this way, according to the shock absorber 2, it is possible to increase the pull-out load of the rod 20 from the outer cylinder 11, for example, without increasing the strength of the bent portion 15 (in other words, without increasing the thickness of the second portion 112 of the outer cylinder 11 or changing the shape of the bent portion 15).

[0042] The shock absorber 2 also includes an annular ring 69 provided between the recess 114 of the outer cylinder 11 and the bent portion 66 of the cap 60. By interposing the ring 69 between the recess 114 of the outer cylinder 11 and the bent portion 66 of the cap 60, the pullout load of the rod 20 from the outer cylinder 11 becomes larger than when the recess 114 of the outer cylinder 11 and the bent portion 66 of the cap 60 contact each other without the ring 69 interposed therebetween.

[0043] Second Embodiment FIG. 5 is a diagram showing an example of a cross section of a bump stopper 250 according to the second embodiment. FIG. 6 is an example of a perspective view of a bump stopper 250 according to the second embodiment. FIG. 7 is a diagram showing an example of the shape of the bump stopper 250 according to the second embodiment before being connected to the outer cylinder 11. As shown in FIG. The bump stopper 250 according to the second embodiment differs from the bump stopper 50 according to the first embodiment in that it has a cap 260 that corresponds to the cap 60. The differences from the first embodiment will be described below. The same components in the first and second embodiments are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0044] The cap 260 according to the second embodiment differs from the cap 60 according to the first embodiment in that an opposing portion 262 corresponding to the opposing portion 62 is provided. As shown in Fig. 7, the facing portion 262 is cylindrical before being connected to the outer cylinder 11. As shown in Fig. 6, the facing portion 262 has a notch 270 formed by cutting out a part of the cylindrical shape, and the area surrounded by the notch 270 is bent to form the bent portion 266. The notch 270 is formed so as to penetrate the exterior and interior of the facing portion 262, and as shown in FIG. 6 , has a circumferential portion 271 extending in the circumferential direction and axial portions 272 extending from both circumferential ends of the circumferential portion 271 toward the first side. A plurality of (e.g., eight) notches 270 are formed in the circumferential direction. When the bent portion 266 is formed, a second side portion 268, which is a portion on the second side of the portion surrounded by the notch 270, is bent inward from a first side portion 267, which is a portion on the first side of the portion surrounded by the notch 270, as a base end. The second side portion 268 is fitted into the recess 114 of the outer cylinder 11, and a second-side end face 269 of the second side portion 268 contacts a first-side end face 115 of the recess 114, thereby suppressing movement of the cap 260 toward the second side relative to the outer cylinder 11.

[0045] As described above, the cap 260 has the annular portion 61 (see FIG. 2) provided on the second side of the bent portion 15 (see FIG. 2), and the opposing portion 262 protruding from the annular portion 61 to the first side and opposing the outer circumferential surface 113. The opposing portion 262 has a bent portion 266 that is bent inward and fitted into the recess 114 after being placed over the end portion on the second side of the outer cylinder 11.

[0046] According to the cap 260, even if the rod 20 (see FIG. 1) is pulled in the direction of the second side, the second-side end face 269 of the bent portion 266 comes into contact with the first-side end face 115 of the recess 114 of the outer cylinder 11, thereby preventing the rod 20 from coming off the outer cylinder 11. Therefore, according to the cap 260, it is possible to increase the load against which the rod 20 comes off the outer cylinder 11, for example, without increasing the strength of the bent portion 15. [Explanation of symbols]

[0047] 1...Suspension device, 2...Shock absorber, 8...Bump cushion, 10...Cylinder portion, 11...Outer cylinder (an example of a cylinder), 12...Inner cylinder, 15...Bent portion, 20...Rod, 50, 250...Bump stopper, 60, 260...Cap, 61...Annular portion, 62, 262...Facing portion, 64...Groove, 66, 266...Bent portion, 69...Ring, 70...Rod guide portion, 80...Oil seal (an example of a sealing member), 90...Collar, 111...First portion, 112...Second portion, 114...Recess

Claims

1. a rod holding a piston portion at a first end; a cylinder containing the first end of the rod and exposing the second end of the rod, the cylinder containing a liquid; a seal member provided between the rod and the cylinder to seal the inside of the cylinder; a cap attached to the second end of the cylinder; Equipped with the cylinder has a bent portion that is bent inward to prevent the seal member from moving toward the second side, and the cylinder has a recess that is recessed from an outer circumferential surface, the cap has an annular portion provided on the second side of the bent portion, and an opposing portion protruding from the annular portion to the first side and opposing the outer circumferential surface, the opposing portion having a bent portion that is bent inwardly after being placed over the end portion on the second side of the cylinder and fitted into the recess; buffer.

2. The shock absorber according to claim 1 , further comprising an annular ring provided between the recess of the cylinder and the bent portion of the cap.

3. a groove recessed from an inner circumferential surface of the facing portion of the cap; With the ring fitted into the groove and the recess of the cylinder, a portion of the opposing portion on a first side of the groove is bent to form the bent portion. The shock absorber according to claim 2 .

4. The opposing portion of the cap is cylindrical, and a notch is formed in the opposing portion by cutting out a part of the cylindrical shape, and the bent portion is formed by bending a portion surrounded by the notch. The shock absorber according to claim 1 .

5. the second side portion of the portion surrounded by the notch is bent inward with the first side portion of the portion surrounded by the notch as a base end and fitted into the recess, The shock absorber according to claim 4.

6. the cylinder has a first portion that is located closer to the first side than the second end portion and has a thickness that is thicker than the second end portion, The recess is formed in the first portion. The shock absorber according to claim 1 .

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