Bump stopper and shock absorber

Abstract

To provide a bump stopper and the like capable of improving durability.SOLUTION: A bump stopper 100 which stops movement of a bump cushion attached to a rod 20 and is fitted to an end in a center line direction of an outer cylinder 11 includes: a cap 110 which has a cylindrical portion 111 covering an outer peripheral surface of the outer cylinder 11, and a protruding portion 112 protruding inward from the cylindrical portion 111; and a stopper 120 which is joined to the protruding portion 112 and stops movement of the bump cushion. The protruding portion 112 has a thin portion 115 formed in a circumferential direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] Conventionally, a bump stopper has been proposed that cooperates with a bump cushion to absorb the impact generated when a shock absorber is compressed. For example, the bump stopper described in Patent Document 1 includes a cap having a plate-shaped portion with a rod hole through which a piston rod of a shock absorber can be inserted and a cylindrical portion capable of receiving a part of the cylinder of the shock absorber, a stopper provided on the plate-shaped portion for receiving the bump cushion, and a collar provided on the plate-shaped portion facing the cylinder. The thickness of the cap is thinner than that of the stopper and the collar, and the cylindrical portion has a shape that allows it to be fixed to the outer peripheral surface of the cylinder. The stopper is provided on the outer surface of the plate-shaped portion of the cap and is fixed to the cap by projection welding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6616672 Summary of the Invention [Problem to be solved by the invention]

[0004] When joining by projection welding, gaps form between the joined parts at areas other than the joint. For example, in the bump stopper described in Patent Document 1, gaps form between the stopper and the plate-shaped portion of the cap at areas other than the joint. Therefore, when the bump cushion comes into contact with the stopper, the gaps can cause the stopper to bend toward the cap, potentially concentrating stress at the joint. Furthermore, repeated contact between the bump cushion and the stopper can cause cracks to form at the joint, potentially resulting in a lack of durability for the bump stopper. An object of the present invention is to provide a bump stopper or the like that can improve durability. [Means for solving the problem]

[0005] The present invention, which was completed with this objective in mind, is a bump stopper that stops the movement of a bump cushion attached to a rod and is fitted into the end of a cylinder in the centerline direction, and is equipped with a cap having a cylindrical portion that covers the outer surface of the cylinder and a protruding portion that protrudes inward from the cylindrical portion, and a stopper that is joined to the protruding portion and stops the movement of the bump cushion, and the protruding portion has a weak portion formed in the circumferential direction. [Effects of the Invention]

[0006] According to the present invention, it is possible to provide a bump stopper or the like that can improve durability. [Brief explanation of the drawings]

[0007] [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] FIG. 2 is a perspective view of an example of components that constitute a bump stopper. [Figure 5] 10 is an example of a view of the bump stopper as viewed in the axial direction from the second side. [Figure 6] FIG. 6 is an example of a cross-sectional view taken along line VI-VI in FIG. 5. [Figure 7] 1A is a diagram showing an example of a state before the stopper and the protruding portion of the cap are joined by projection welding, and FIG. 1B is a diagram showing an example of a state after the stopper and the protruding portion of the cap are joined by projection welding. [Figure 8] 10A and 10B are diagrams showing an example of a modified mounting mode of the bump stopper; [Figure 9] FIG. 10 is an example of a perspective view of components that constitute a bump stopper according to a second embodiment. [Figure 10] 10 is an example of a cross-sectional view of a bump stopper according to a second embodiment. [Figure 11] 10 is an example of an enlarged view of the bump stopper according to the second embodiment after it has been attached to the outer cylinder. FIG. [Figure 12] 10A and 10B are diagrams showing an example of a modified mounting mode of the bump stopper according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] 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. FIG. 3 is an example of an enlarged view of part III in FIG. FIG. 4 is an example of a perspective view of the components that make up the bump stopper 100. As shown in FIG. FIG. 5 is an example of a view of the bump stopper 100 as viewed in the axial direction from the second side. FIG. 6 is an example of a cross-sectional view taken along line VI-VI in FIG.

[0009] 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 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 has a bump cushion 8 that is attached to the vehicle body mounting bracket 6 and absorbs the impact when a rod 20 (described later) compresses. The bump cushion 8 is molded from a material with a low elastic modulus such as synthetic rubber, and is a cylindrical elastic member that is provided around the outer circumferential surface of a rod portion 21 of the rod 20.

[0011] (buffer 2) The shock absorber 2 will be described in detail below. As shown in Figure 1, the shock absorber 2 is a twin-cylinder shock absorber. The shock absorber 2 includes a cylinder portion 10 that stores 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 50 that is fixed to the rod 20, and a rebound rubber 51 that is an annular elastic member that is arranged on the second side of the rebound seat 50, in order to absorb the impact when the rod 20 extends.

[0012] [Cylinder section 10] The cylinder section 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 and the inner cylinder 12 are arranged so that the center line direction of the cylinders coincides with the axial direction. The outer cylinder 11 has a bent portion 15 formed by bending the second end of the cylindrical shape inward, a process known as roll caulking.

[0013] 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.

[0014] The cylinder section 10 includes a rod guide section 60 that is disposed inside the outer cylinder 11, blocks the second end of the inner cylinder 12, and movably (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 60 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. The cylinder section 10 also includes a bump stopper 100 that is attached to the second end of the outer cylinder 11.

[0015] [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. A rebound seat 50 is fixed to the first end of the rod 20 .

[0016] [Piston portion 30] The piston section 30 includes a piston 31, a first side valve group 32 that closes the first side ends of some of the oil passages formed in the piston 31, and a second side valve group 33 that closes the second side ends of some of the oil passages formed in the piston 31.

[0017] [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 .

[0018] [Rod guide part 60] The rod guide portion 60 includes a thin-walled cylindrical guide 61 disposed inside, and a guide case 70 that holds the guide 61 inside.

[0019] The inner diameter of the guide 61 is set to be slightly larger than the outer diameter of the rod 20 inserted inside. For example, the inner diameter of the guide 61 is 0.1 mm to 1 mm larger than the outer diameter of the rod 20. The inner peripheral surface of the guide 61 comes into contact with the outer peripheral surface of the rod 20, so the guide 61 is formed from a material that is more wear-resistant than the guide case 70.

[0020] The guide case 70 has a cylindrical inner cylindrical portion 71 provided on the inside, and a cylindrical outer cylindrical portion 72 provided on the outside of the inner cylindrical portion 71. The inner cylindrical portion 71 and the outer cylindrical portion 72 are preferably integrally molded such that the outer peripheral surface of a portion of the inner cylindrical portion 71 on the second axial side and the inner peripheral surface of a portion of the outer cylindrical portion 72 on the first axial side are joined together.

[0021] A guide 61 is fitted inside the inner cylindrical portion 71 . The outer cylindrical portion 72 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 72 is smaller than the inner diameter of the second end of the outer cylinder 11. The outer cylindrical portion 72 has an inner recess 721 recessed from the upper end surface 720 formed inside the upper end, and an outer recess 722 recessed from the upper end surface 720 formed outside the upper end. The guide case 70 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 ring 81 made of a 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 ring 81, and the ring 81 holds the elastic portion 82. The oil seal 80 is disposed on the second side of the rod guide portion 60, and is held to the outer cylinder 11 via a collar 90 by performing so-called roll caulking, in which the end portion on the second side of the outer cylinder 11 is bent inward.

[0023] The ring 81 can be exemplified as a thin annular ring having an inner diameter larger than the outer diameter of the rod 20, an outer diameter smaller than the inner diameter of the second end of the outer cylinder 11, and larger than the outer diameter of the outer cylindrical portion 72 of the guide case 70.

[0024] The elastic portion 82 is provided on the first side of the ring 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 circumference of the outer circumferential surface 211 of the rod 20. The elastic portion 82 also has a dust lip 822 that is provided on the second side of the ring 81 and comes into close contact with the entire circumference of the outer circumferential surface 211 of the rod 20, thereby preventing dust from entering from the outside.

[0025] The elastic part 82 also has an outer circumferential seal part 823 that protrudes from the outer periphery of the ring 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 722 of the guide case 70 of the rod guide part 60 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 70 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 circumferential portion of the ring 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 721 of the outer cylindrical portion 72 of the guide case 70, thereby preventing oil from flowing toward the upper end surface 720 of the outer cylindrical portion 72.

[0027] [Color 90] The collar 90 is a thin, annular member. The collar 90 has an inner diameter larger than the outer diameter of the dust lip 822 of the elastic portion 82 of the oil seal 80, and an outer diameter smaller than the inner diameter of the second-side end of the outer cylinder 11 and larger than the outer diameter of the ring 81 of the oil seal 80. The thickness of the collar 90 is determined so that a stopper 120 (described later) of the bump stopper 100 is located on the second side of the dust lip 822 of the oil seal 80.

[0028] [Bump Stopper 100] The bump stopper 100 includes a cap 110 that covers the outer peripheral surface of the outer cylinder 11, and a stopper 120 that stops the movement of the bump cushion 8. The cap 110 and the stopper 120 may be formed from metal, for example. The thickness of the cap 110 is equal to or less than the thickness of the outer cylinder 11, and the thickness of the stopper 120 is greater than the thickness of the outer cylinder 11.

[0029] The cap 110 has a cylindrical tubular portion 111 that covers the periphery of the outer peripheral surface of the outer cylinder 11, and a protruding portion 112 that protrudes inward from a second end of the tubular portion 111. The cap 110 has notches 113 formed by cutting out parts of the second end of the tubular portion 111 and the protruding portion 112 in the circumferential direction. FIG. 4 shows an example in which two notches 113 are formed. However, the number of notches 113 is not particularly limited and may be one, or three or more. The tubular portion 111 and the protruding portion 112 are connected by a bend R that fits the outer shape of the outer cylinder 11.

[0030] The inner diameter of the cylindrical portion 111 is equal to or smaller than the outer diameter of the outer cylinder 11. The cap 110 is attached to the outer cylinder 11 by fitting (in other words, press-fitting) the cylindrical portion 111 onto the outside of the outer cylinder 11. However, the method for fixing the cylindrical portion 111 to the outer cylinder 11 is not particularly limited. For example, the cylindrical portion 111 and the outer cylinder 11 may be fixed by welding, melting, or adhesive.

[0031] The protruding portion 112 is flat and formed to protrude inward from the entire second end portion of the cylindrical portion 111. The protruding portion 112 also forms a hole 114 on the inside thereof through which the dust lip 822 of the oil seal 80 provided around the rod 20 can pass.

[0032] The protruding portion 112 has a thin-walled portion 115 whose thickness is smaller than that of other portions of the protruding portion 112. The thin-walled portion 115 is formed so as to be recessed from an opposing surface 116 of the protruding portion 112 that faces the stopper 120. The thickness of the thin-walled portion 115 can be, for example, half the thickness of the other portions of the protruding portion 112. The thin-walled portion 115 is formed so as to extend in the circumferential direction over the entire area of ​​the protruding portion 112. The thin-walled portion 115 is provided at a position where the radial dimension from the center line of the rod 20 is smaller than the radial dimension from the center line of the rod 20 to the innermost portion of the bent portion 15 of the outer cylinder 11. The thin-walled portion 115 is also provided outside a joint portion 130, which will be described later. The radial dimension of the thin-walled portion 115 can be, for example, equal to or greater than the thickness of the thin-walled portion 115 and equal to or less than the radial dimension of the joint portion 130.

[0033] The stopper 120 is an annular member having a first surface 121 which is a surface on the first side and a second surface 122 which is a surface on the second side. The inner diameter of the stopper 120 is larger than the outer diameter of the rod portion 21 of the rod 20 and smaller than the diameter of the hole 114 of the protruding portion 112 of the cap 110. For example, the outer diameter of the stopper 120 may be the same as the inner diameter of the cylindrical portion 111 of the cap 110.

[0034] The stopper 120 and the protruding portion 112 of the cap 110 are joined by projection welding. Therefore, the bump stopper 100 has a joint 130 between the stopper 120 and the protruding portion 112 of the cap 110, which is formed by projection welding. A plurality of joints 130 are provided in the circumferential direction. In the example shown in FIG. 2, there are five joints 130, but the number of joints 130 is not limited.

[0035] Fig. 7(a) is a diagram showing an example of a state before the stopper 120 and the protruding portion 112 of the cap 110 are joined by projection welding. Fig. 7(b) is a diagram showing an example of a state after the stopper 120 and the protruding portion 112 of the cap 110 are joined by projection welding. Before the stopper 120 and the cap 110 are joined by projection welding, as shown in FIG. 7( a), the stopper 120 has a protrusion 123 protruding from a first surface 121. The protrusion 123 can be formed, for example, by press working. Therefore, the stopper 120 has a recess 124 recessed from a second surface 122. When projection welding is performed, the tip of the protrusion 123 of the stopper 120 is brought into contact with the opposing surface 116 of the cap 110, and pressure is applied to the protrusion 123 while a large current is concentrated through the protrusion 123. As a result, as shown in FIG. 7( b), the heat generated in the protrusion 123 melts the protrusion 123, and the stopper 120 and the protrusion 112 of the cap 110 are welded together, forming a joint 130. Before the bump stopper 100 is press-fitted into the outer cylinder 11, a gap is generated between the first surface 121 of the stopper 120 and the opposing surface 116 of the protruding portion 112 of the cap 110.

[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 50 are attached is inserted into the inner cylinder 12 from the piston part 30 side, and the rebound rubber 51 is inserted into the inner cylinder 12.

[0037] Thereafter, the rod guide unit 60 is inserted into the outer cylinder 11. At this time, the inner cylindrical portion 71 of the guide case 70 of the rod guide unit 60 is inserted into the inner cylinder 12, and the first side surface of the outer cylindrical portion 72 is brought into contact with the second side surface of the inner cylinder 12. The inner cylinder 12 is restrained from moving in the axial direction by the valve body 41 of the bottom portion 40 and the outer cylindrical portion 72 of the guide case 70 of the rod guide unit 60. Furthermore, the inner cylinder 12 is restrained from moving in the radial direction by the valve body 41 of the bottom portion 40 and the inner cylindrical portion 71 of the guide case 70.

[0038] After inserting the rod guide part 60 into the outer cylinder 11, the oil seal 80 is inserted into the outer cylinder 11 until the first side surface of the ring 81 of the oil seal 80 contacts the upper end surface 720 of the outer cylindrical part 72 of the guide case 70. 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.

[0040] After the bent portion 15 is formed in the outer cylinder 11, the bump stopper 100 is press-fitted into the outer cylinder 11. When press-fitting the bump stopper 100 into the outer cylinder 11, the first end face 117 of the protruding portion 112 of the cap 110 is brought into contact with the bent portion 15 of the outer cylinder 11, and then pressure is applied until the opposing surface 116 of the protruding portion 112 comes into contact with the first surface 121 of the stopper 120. Because the protruding portion 112 of the cap 110 has the thin-walled portion 115, it is possible to bring the opposing surface 116 of the protruding portion 112 into contact with the first surface 121 of the stopper 120 with a lower pressure than when, for example, the protruding portion 112 does not have the thin-walled portion 115. Furthermore, the bent portion 15 of the outer cylinder 11 comes into contact with the protruding portion 112 outside the thin-walled portion 115. Therefore, it is easier to apply pressure so that the opposing surface 116 of the protrusion 112 and the first surface 121 of the stopper 120 come into contact than, for example, when the bent portion 15 of the outer cylinder 11 comes into contact both outside and inside the thin-walled portion 115.

[0041] As described above, the bump stopper 100 stops the movement of the bump cushion 8 attached to the rod 20, and is fitted into the end of the outer cylinder 11 (an example of a cylinder) in the center line direction (in other words, the axial direction). The bump stopper 100 also includes a cap 110 having a cylindrical portion 111 that covers the periphery of the outer peripheral surface of the outer cylinder 11 and a protruding portion 112 that protrudes inward from the cylindrical portion 111, and a stopper 120 that is joined to the protruding portion 112 to stop the movement of the bump cushion 8. The protruding portion 112 has a thin-walled portion 115 (an example of a fragile portion) formed in the circumferential direction.

[0042] The bump stopper 100 configured as described above is easily deformed so as to reduce the gap between the protrusion 112 of the cap 110 and the stopper 120 after being fitted onto the end of the outer cylinder 11. Therefore, it can be easily assembled so that the opposing surface 116 of the protrusion 112 of the cap 110 and the first surface 121 of the stopper 120 come into contact. Therefore, even if the bump cushion 8 comes into contact with the stopper 120, the stopper 120 is less likely to bend toward the cap 110, making it possible to reduce the concentration of stress at the joint 130. As a result, with the bump stopper 100, it is possible to reduce the likelihood of cracks occurring at the joint 130 even if the bump cushion 8 and the stopper 120 repeatedly come into contact with each other, thereby increasing the durability of the bump stopper 100.

[0043] Here, the thin-walled portion 115 is a portion whose thickness is thinner than the thickness of other portions (for example, portions inside the joint portion 130) of the protruding portion 112. This makes it easier for the bump stopper 100 to deform, starting from the thin-walled portion 115, so that the gap between the protruding portion 112 and the stopper 120 becomes smaller. Furthermore, the thin-walled portion 115 is formed at a location outside the joint 130 between the stopper 120 and the protruding portion 112. This makes it easier for the portion of the protruding portion 112 corresponding to the bent portion 15 of the outer cylinder 11 to deform toward the stopper 120.

[0044] The shock absorber 2 also includes an outer cylinder 11, a bump cushion 8 attached to a rod 20 exposed from the outer cylinder 11, and a bump stopper 100 that stops the movement of the bump cushion 8 and is fitted into the end of the outer cylinder 11 in the centerline direction. The outer cylinder 11 has a bent portion 15 formed by rolling the end of the centerline direction, and the bump stopper 100 is fitted into the outer cylinder 11 until the protruding portion 112 comes into contact with the bent portion 15. As a result, the bump stopper 100 can be easily assembled so that the gap between the protruding portion 112 of the cap 110 and the stopper 120 is small.

[0045] Furthermore, thin portion 115 is formed between joint 130 between stopper 120 and protrusion 112 and the portion in contact with bent portion 15. This makes it easier for bump stopper 100 to deform toward stopper 120 at the portion of protrusion 112 that contacts bent portion 15, and makes it easier for bump stopper 100 to deform so that the gap between protrusion 112 and stopper 120 becomes smaller with high accuracy.

[0046] Furthermore, the protrusion 112 of the cap 110 and the stopper 120 are joined by projection welding, and there is a gap between the protrusion 112 and the stopper 120 at a portion of the protrusion 112 that is inside the joint 130, but there is no gap between the protrusion 112 and the stopper 120 at a portion outside the joint 130. Therefore, even if the bump cushion 8 comes into contact with the stopper 120, the stopper 120 is less likely to bend toward the cap 110 at a portion outside the joint 130, and stress is less likely to concentrate at the joint 130. As a result, even if the bump cushion 8 and the stopper 120 come into repeated contact with each other, cracks are less likely to occur at the joint 130, and the bump stopper 100 has high durability.

[0047] In the bump stopper 100, the thin-walled portion 115 does not have to be formed over the entire area of ​​the protruding portion 112. The thin-walled portion 115 may be formed only in a partial area of ​​the protruding portion 112. In other words, three or more thin-walled portions 115 may be formed in the circumferential direction. Furthermore, instead of being recessed from the opposing surface 116 of the protruding portion 112, the thin-walled portion 115 may be recessed from the first-side surface of the protruding portion 112. Furthermore, the thin-walled portion 115 may be recessed from both the opposing surface 116 of the protruding portion 112 and the first-side end surface 117 (an example of the surface on the outer cylinder 11 side) of the protruding portion 112.

[0048] (Modification of Mounting Mode of Bump Stopper 100) FIG. 8 is a diagram showing an example of a modified mounting mode of the bump stopper 100. In FIG. The mounting of the cap 110 on the outer cylinder 11 is not limited to a mode in which pressure is applied until the opposing surface 116 of the protrusion 112 contacts the first surface 121 of the stopper 120. As shown in FIG. 8 , the bump stopper 100 may be pressed so that the opposing surface 116 of the protrusion 112 does not contact the first surface 121 of the stopper 120. In other words, the bump stopper 100 may be mounted on the outer cylinder 11 so that the gap between the stopper 120 and a portion of the protrusion 112 outside the joint 130 is smaller than the gap between the stopper 120 and a portion of the protrusion 112 inside the joint 130. This reduces the amount of deflection of the stopper 120, even if the bump cushion 8 contacts the stopper 120, compared to when the gap between the stopper 120 and the portion of the protrusion 112 outside the joint 130 and the portion inside the joint 130 is uniform. As a result, even if the bump cushion 8 and the stopper 120 come into contact repeatedly, cracks are unlikely to occur in the joint 130, and the durability of the bump stopper 100 is therefore increased.

[0049] Second Embodiment FIG. 9 is an example of a perspective view of components that constitute the bump stopper 200 according to the second embodiment. FIG. 10 is an example of a cross-sectional view of a bump stopper 200 according to the second embodiment. FIG. 11 is an example of an enlarged view of the bump stopper 200 according to the second embodiment after it has been attached to the outer cylinder 11. As shown in FIG. The bump stopper 200 according to the second embodiment differs from the bump stopper 100 according to the first embodiment in that it has a cap 210 that corresponds to the cap 110. 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.

[0050] The cap 210 according to the second embodiment differs from the cap 110 according to the first embodiment in that the cap 210 has a protruding portion 212 corresponding to the protruding portion 112. The protruding portion 212 differs from the protruding portion 112 in that, instead of having the thin-walled portion 115, a groove 215 is formed that is recessed from the opposing surface 116 and extends in the circumferential direction. The groove 215 is formed over the entire area of ​​the protruding portion 212. In other words, the protruding portion 212 is divided into two regions by the two cutouts 113, and therefore two grooves 215 are formed in the circumferential direction. For example, the shape of the groove 215 cut along a plane parallel to the axial direction can be V-shaped. Note that, for example, the radial position of the groove 215 can be the same as the radial position of the thin-walled portion 115.

[0051] As described above, the bump stopper 200 includes the cylindrical portion 111 that covers the periphery of the outer peripheral surface of the outer cylinder 11, the cap 210 that has the protruding portion 212 that protrudes inward from the cylindrical portion 111, and the stopper 120 that is joined to the protruding portion 212 to stop the movement of the bump cushion 8. The protruding portion 212 has a groove 215 (an example of a fragile portion) formed in the circumferential direction.

[0052] The bump stopper 200 configured as described above is easily deformed to reduce the gap between the protrusion 212 of the cap 210 and the stopper 120 after being fitted onto the end of the outer cylinder 11. Therefore, it can be easily assembled so that the opposing surface 116 of the protrusion 212 of the cap 210 and the first surface 121 of the stopper 120 come into contact. Therefore, even if the bump cushion 8 comes into contact with the stopper 120, the stopper 120 is less likely to bend toward the cap 210, making it possible to reduce the concentration of stress at the joint 130. As a result, the bump stopper 200 makes it less likely for cracks to occur at the joint 130 even if the bump cushion 8 and the stopper 120 come into repeated contact with each other, thereby increasing the durability of the bump stopper 100.

[0053] In the bump stopper 200, the groove 215 does not have to be formed over the entire area of ​​the protruding portion 212. The groove 215 may be formed only in a partial area of ​​the protruding portion 212. In other words, three or more grooves 215 may be formed in the circumferential direction. In addition, the cross-sectional shape of the groove 215 is not limited to a V-shape. For example, the cross-sectional shape of the groove 215 may be an arc shape.

[0054] Furthermore, instead of being recessed from the opposing surface 116 of the protruding portion 212, the groove 215 may be recessed from the first side surface of the protruding portion 212. Furthermore, the groove 215 may be recessed from both the opposing surface 116 and the first side surface of the protruding portion 212. In other words, the groove 215 may be formed in both the opposing surface 116, which is the surface of the protruding portion 212 facing the bump cushion 8, and the first side end surface 117, which is the surface of the outer cylinder 11.

[0055] (Modification of Mounting Mode of Bump Stopper 200) FIG. 12 is a diagram showing an example of a modified mounting mode of the bump stopper 200 according to the second embodiment. Attaching the cap 210 to the outer cylinder 11 is not limited to a mode in which pressure is applied until the opposing surface 116 of the protrusion 212 contacts the first surface 121 of the stopper 120. As shown in FIG. 12 , the bump stopper 200 may be pressed so that the opposing surface 116 of the protrusion 212 does not contact the first surface 121 of the stopper 120. In other words, the bump stopper 200 may be attached to the outer cylinder 11 so that the gap between the stopper 120 and a portion of the protrusion 212 outside the joint 130 is smaller than the gap between the stopper 120 and a portion of the protrusion 212 inside the joint 130. This reduces the amount of deflection of the stopper 120, even if the bump cushion 8 contacts the stopper 120, compared to when the gap between the stopper 120 and the portion of the protrusion 212 outside the joint 130 and the portion inside the joint 130 is uniform. As a result, even if the bump cushion 8 and the stopper 120 come into contact repeatedly, cracks are unlikely to occur in the joint 130, and the durability of the bump stopper 200 is therefore increased. [Explanation of symbols]

[0056] 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, 60...rod guide portion, 80...oil seal, 90...collar, 100, 200...bump stopper, 110...cap, 111...cylindrical portion, 112, 212...protruding portion, 115...thin-walled portion (an example of a fragile portion), 117...end surface, 120...stopper, 130...joint portion, 215...groove (an example of a fragile portion)

Claims

1. A bump stopper that stops the movement of a bump cushion attached to a rod and is fitted into an end of the cylinder in the center line direction, a cap having a cylindrical portion that covers the outer circumferential surface of the cylinder and a protruding portion that protrudes inward from the cylindrical portion; a stopper joined to the protrusion to stop the movement of the bump cushion; Equipped with The protrusion has a weakened portion formed in the circumferential direction. Bump stopper.

2. The fragile portion is a portion having a thickness thinner than that of other portions of the protruding portion. The bump stopper according to claim 1 .

3. The weakened portion is a groove extending in the circumferential direction. The bump stopper according to claim 1 .

4. The grooves are formed in a plurality in the circumferential direction.

4. The bump stopper according to claim 3.

5. the groove is formed on both the bump cushion side surface and the cylinder side surface of the protrusion; 4. The bump stopper according to claim 3.

6. the weakened portion is formed at a location outside a joint between the stopper and the protrusion. The bump stopper according to claim 1 .

7. A cylinder; a bump cushion attached to a rod exposed from the cylinder; a bump stopper that stops the movement of the bump cushion and is fitted to an end of the cylinder in the center line direction; Equipped with The bump stopper includes a cap having a cylindrical portion that covers the periphery of the outer peripheral surface of the cylinder and a protruding portion that protrudes inward from the cylindrical portion, and a stopper that is joined to the protruding portion to stop movement of the bump cushion, and the protruding portion has a weakened portion formed in the circumferential direction. buffer.

8. the cylinder has a bent portion formed by rolling an end portion in the centerline direction, the bump stopper is fitted into the cylinder until the protruding portion contacts the bent portion. The shock absorber according to claim 7.

9. the weakened portion is formed between a joint between the stopper and the protruding portion and a portion in contact with the bent portion. The shock absorber according to claim 8.

10. the protrusion of the cap and the stopper are joined by projection welding, a gap exists between the stopper and a portion of the protrusion that is inside the joint, but no gap exists between the stopper and a portion of the protrusion that is outside the joint; The shock absorber according to claim 9.

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