Buffer

Abstract

To provide a buffer capable of improving load resistance of a cylinder.SOLUTION: A buffer comprises a piston rod 31 protruding from an axial end part of a cylinder 15, and a bumper cap 3 provided at the axial end part of the cylinder 15 and having a bottom part 86 with a hole part 87 into which the piston rod 31 can be inserted, and a cylindrical part 85 covering a radial outer periphery of the cylinder 15. The bumper cap 3 has a rib 92 at a radial inside portion of the bottom part 86, the rib which protrudes axially beyond a radial outside part 111 of the bottom part 86. The buffer comprises a plate 4 fixed to the bumper cap 3 and having an outer abutment part 123 that abuts on the outside part 111 and a rib abutment part 122 that abuts on the rib 92.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] Some shock absorbers have a plate provided on the upper surface of the bumper cap (see, for example, Patent Document 1). Also, some shock absorbers have a plate with projections and recesses provided on the upper surface of the outer cylinder (see, for example, Patent Document 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-96369 A [Patent Document 2] Japanese Patent Application Publication No. 9-317811 Summary of the Invention [Problem to be solved by the invention]

[0004] In shock absorbers, there is a demand for improving the load bearing performance of the cylinders.

[0005] Therefore, an object of the present invention is to provide a shock absorber capable of improving the load-bearing performance of a cylinder. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, the present invention provides a shock absorber comprising a cylinder in which a working fluid is sealed, a piston rod protruding from an axial end of the cylinder, and a bumper cap provided at the axial end of the cylinder, the bumper cap having a bottom having a hole through which the piston rod can be inserted and a cylindrical portion covering the radial outer periphery of the cylinder, wherein the bumper cap has a rib at a radially inner portion of the bottom that protrudes axially beyond an outer portion of the bottom in the radial direction, and a plate having an outer abutment portion that abuts the outer portion and a rib abutment portion that abuts the rib and is fixed to the bumper cap. Effect of the Invention

[0007] According to the present invention, it is possible to improve the load-bearing performance of the cylinder. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing a shock absorber according to a first embodiment of the present invention. [Diagram 2] 2 is a cross-sectional view showing a main portion of the shock absorber of the first embodiment according to the present invention, the cross-section of the bumper cap assembly taken along line II-II shown in FIG. [Diagram 3] FIG. 1 is a plan view showing a bumper cap assembly of a shock absorber according to a first embodiment of the present invention. [Figure 4] 1 is a sectional perspective view showing an outer cylinder, a plate, and a bumper cap of a shock absorber according to a first embodiment of the present invention. FIG. [Diagram 5] FIG. 4 is a cross-sectional view showing a bumper cap assembly according to a second embodiment of the present invention. [Figure 6] FIG. 11 is a cross-sectional view showing a bumper cap assembly according to a third embodiment of the present invention. [Figure 7] FIG. 11 is a cross-sectional view showing a bumper cap assembly according to a fourth embodiment of the present invention. [Figure 8] FIG. 11 is a cross-sectional view showing a bumper cap assembly according to a fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [First embodiment] A shock absorber according to a first embodiment of the present invention will be described below with reference to Fig. 1 to Fig. 4. The shock absorber 1 according to the first embodiment shown in Fig. 1 is a shock absorber used in a suspension device of a vehicle such as an automobile or a railroad car. The shock absorber 1 includes a shock absorber body 2 and a bumper cap assembly 5 having a bumper cap 3 and a plate 4.

[0010] First, the shock absorber body 2 will be described. The shock absorber body 2 has a cylindrical metal inner tube 12 and a bottomed, cylindrical metal outer tube 14 that is larger in diameter than the inner tube 12, is provided on the outer periphery of the inner tube 12, and forms a reservoir chamber 13 between the inner tube 12 and the outer tube 14. In other words, the shock absorber 1 is a double-cylinder shock absorber in which the outer tube 14 and the inner tube 12 form a cylinder 15. In the cylinder 15, oil liquid L is sealed in the inner tube 12 as a working fluid, and oil liquid L and gas G are sealed in the reservoir chamber 13 between the outer tube 14 and the inner tube 12 as a working fluid.

[0011] The outer cylinder 14 is composed of a cylindrical body 17 and a bottom 18 that closes one axial end of the body 17. The inner cylinder 12 is cylindrical. The inner cylinder 12 is engaged with the bottom 18 of the outer cylinder 14 via an annular base member 20 attached to one axial end of the inner cylinder 12. The inner cylinder 12 is also engaged with an opening 19 on the side opposite the bottom 18 of the body 17 of the outer cylinder 14 via an annular rod guide 21 attached to the other axial end of the inner cylinder 12.

[0012] The base member 20 is placed on the bottom 18 of the outer cylinder 14 while being fitted and fixed to the inner cylinder 12, and is positioned in the radial direction at that time. As a result, one axial end of the base member 20 and the inner cylinder 12 is arranged coaxially with the outer cylinder 14. The rod guide 21 is fitted into the inner cylinder 12 and the body portion 17 of the outer cylinder 14, thereby arranging the other axial end of the inner cylinder 12 coaxially with the outer cylinder 14.

[0013] An annular seal member 23 is disposed on the opposite side of the rod guide 21 from the bottom 18, and this seal member 23 is also fitted into the inner periphery of the opening 19 side of the body 17. The opening 19 of the outer tube 14 is located axially outboard of the inner tube 12, and therefore also serves as the opening of the cylinder 15. An engagement portion 24 is formed by bending the end of the outer tube 14 on the opening 19 side radially inward, and the radial outer portion of the seal member 23 is sandwiched between this engagement portion 24 and the rod guide 21.

[0014] A piston 25 is slidably fitted in the inner cylinder 12. The piston 25 defines a first chamber 28 and a second chamber 29 in the inner cylinder 12. The first chamber 28 is provided between the piston 25 and the rod guide 21 in the inner cylinder 12, and the second chamber 29 is provided between the piston 25 and the base member 20 in the inner cylinder 12. The second chamber 29 in the inner cylinder 12 is defined as a reservoir chamber 13 by the base member 20.

[0015] A rod-shaped metal piston rod 31 is connected to the piston 25 by a nut 32. The piston rod 31 has a cylindrical main shaft portion 33 with a constant outer diameter, and the main shaft portion 33 passes through the rod guide 21 and the seal member 23 and extends to the outside from the opening 19 of the cylinder 15. The main shaft portion 33 of the piston rod 31 is slidably inserted into the inside of the rod guide 21 and the seal member 23. One axial end side of the piston rod 31 is disposed inside the outer cylinder 14 and the inner cylinder 12, and the other end side is disposed outside the outer cylinder 14 and the inner cylinder 12. The piston rod 31 moves in the axial direction together with the piston 25. The piston rod 31 protrudes from the axial end opposite the bottom 18 of the cylinder 15.

[0016] The seal member 23, through which the main shaft portion 33 of the piston rod 31 is inserted, closes the gap between the outer tube 14 and the piston rod 31 at the position of the opening 19 of the cylinder 15, and prevents the oil L in the inner tube 12 and the gas G and oil L in the reservoir chamber 13 from leaking out to the outside. The seal member 23 makes sliding contact with the main shaft portion 33 when the piston rod 31 moves in the axial direction.

[0017] Piston 25 is formed with passages 34 and 35 penetrating in the axial direction. Passages 34, 35 are capable of communicating between first chamber 28 and second chamber 29. Piston 25 is provided with an annular disk valve 36 on the axial opening 19 side, which is capable of closing passage 34 by abutting against piston 25. Piston 25 is also provided with an annular disk valve 37 on the axial bottom 18 side, which is capable of closing passage 35 by abutting against piston 25.

[0018] The disc valve 36 opens the passage 34 when the piston rod 31 moves to the compression side increasing the amount of entry into the inner cylinder 12 and the outer cylinder 14 and the piston 25 moves in a direction narrowing the second chamber 29, causing the pressure in the second chamber 29 to be higher than the pressure in the first chamber 28 by a predetermined value or more, generating a damping force. At least one of the piston 25 and the disc valve 36 is formed with a fixed orifice (not shown) that communicates between the first chamber 28 and the second chamber 29 via the passage 34 even when the disc valve 36 is in a state where the passage 34 is most blocked.

[0019] The disc valve 37 opens the passage 35 when the piston rod 31 moves to the extension side increasing the amount of protrusion from the inner cylinder 12 and the outer cylinder 14 and the piston 25 moves in a direction narrowing the first chamber 28, causing the pressure in the first chamber 28 to be higher than the pressure in the second chamber 29 by a predetermined value or more, generating a damping force. At least one of the piston 25 and the disc valve 37 is formed with a fixed orifice (not shown) that communicates between the first chamber 28 and the second chamber 29 via the passage 35 even when the disc valve 37 is in a state where the passage 35 is most blocked.

[0020] The base member 20 is formed with passages 41 and 42 penetrating in the axial direction. The passages 41, 42 are capable of communicating between the second chamber 29 and the reservoir chamber 13. The base member 20 is provided with an annular disk valve 43 on the axial bottom 18 side thereof, which is capable of closing the passage 41 by abutting against the base member 20, and the base member 20 is provided with an annular disk valve 44 on the opposite side of the axial bottom 18 thereof, which is capable of closing the passage 42 by abutting against the base member 20.

[0021] The disc valve 43 is a check valve that allows the flow of oil L from the second chamber 29 to the reservoir chamber 13 side through the passage 41 and restricts the flow of oil L in the opposite direction through the passage 41. The disc valve 43 serves as a damping valve that opens the passage 41 when the piston rod 31 moves to the compression side and the pressure in the second chamber 29 becomes higher than the pressure in the reservoir chamber 13 by a predetermined value or more, thereby generating a damping force at that time.

[0022] The disc valve 44 is a check valve that allows the flow of oil L from the reservoir chamber 13 to the second chamber 29 via the passage 42 and restricts the flow of oil L in the opposite direction via the passage 42. The disc valve 44 opens the passage 42 when the piston rod 31 moves to the extension side, the piston 25 moves to the first chamber 28 side, and the pressure in the second chamber 29 drops below the pressure in the reservoir chamber 13. At that time, the disc valve 44 is a suction valve that allows the oil L to flow from the reservoir chamber 13 into the second chamber 29 without generating any substantial damping force.

[0023] A cylindrical mounting eye 46 is secured to the exterior of the bottom portion 18 of the barrel 14 .

[0024] The bumper cap assembly 5 is attached to the shock absorber body 2 on the opposite side to the bottom 18 of the outer cylinder 14. In this state, the shock absorber body 2 is attached to the relative moving part of the object to be attached, with the part of the piston rod 31 outside the bumper cap assembly 5 and the mounting eye 46. In the shock absorber body 2, the piston 25 slides axially together with the piston rod 31 in the inner cylinder 12 of the cylinder 15 due to the relative movement of the object to be attached, changing the volumes of the first chamber 28 and the second chamber 29, and at that time, a damping force is generated by the flow resistance of the oil liquid L generated in the piston 25 and the base member 20. For example, the piston rod 31 is arranged at an upper position and connected to the vehicle body side of the vehicle, and the mounting eye 46 is arranged at a lower position and connected to the wheel side of the vehicle, generating a damping force against the movement of the wheel relative to the vehicle body.

[0025] 2, the rod guide 21 has a substantially stepped annular shape, with a large diameter section 51 having a cylindrical outer circumferential surface formed on one axial side, and a small diameter section 52 having a cylindrical outer circumferential surface with a smaller diameter than the large diameter section 51 formed on the other axial side. The large diameter section 51 and the small diameter section 52 are formed coaxially, and the rod guide 21 fits into the inner circumferential surface of the body section 17 of the outer cylinder 14 at the large diameter section 51, and fits into the inner circumferential surface of the inner cylinder 12 at the small diameter section 52.

[0026] An annular convex portion 55 is formed in the axial direction at the end of the rod guide 21 on the side of the large diameter portion 51. A communication hole 56 is formed in the annular convex portion 55 at a radially inner position thereof, penetrating the rod guide 21 along the axial direction. The communication hole 56 opens into the reservoir chamber 13 between the outer tube 14 and the inner tube 12 on the opposite side of the annular convex portion 55 in the axial direction of the rod guide 21.

[0027] The seal member 23 is an integrally molded product in which a metallic, disk-shaped, perforated annular member 62 is embedded in a synthetic rubber sealing material 61. The annular member 62 is for maintaining the shape of the sealing material 61, and for providing the seal member 23 with the strength required for fixing it to a target portion. The seal member 23 is supported on one end side of the cylinder 15, with the radial position of the annular member 62 being sandwiched between the annular protrusion 55 of the rod guide 21 and the locking portion 24 of the outer cylinder 14.

[0028] The seal material 61 has a dust lip portion 71 , an oil lip portion 72 , a seal ring portion 73 , and a check lip portion 74 .

[0029] The dust lip portion 71 extends in a cylindrical shape from the inner peripheral surface side of the annular member 62 to one side in the axial direction. The dust lip portion 71 passes through the opening 19 of the outer tube 14 and protrudes outward from the outer tube 14, i.e., outward from the cylinder 15. The oil lip portion 72 extends in a cylindrical shape from the inner peripheral surface side of the annular member 62 to the other side in the axial direction. The seal member 23 has the main shaft portion 33 of the piston rod 31 inserted inside the oil lip portion 72 and dust lip portion 71 so as to be in sliding contact with the main shaft portion 33 of the piston rod 31, and the dust lip portion 71 and oil lip portion 72 seal the gap with the main shaft portion 33 of the piston rod 31.

[0030] The seal ring portion 73 protrudes in an annular shape from the outer circumferential surface side of the annular member 62 on the same side as the oil lip portion 72 in the axial direction. The seal ring portion 73 simultaneously contacts the annular protrusion 55 of the rod guide 21 and the body portion 17 of the outer tube 14 to seal the gap between the outer tube 14 and the rod guide 21.

[0031] The check lip portion 74 protrudes in the shape of a circular cylinder from a radially intermediate position of the annular member 62 on the same side as the oil lip portion 72 in the axial direction. The check lip portion 74 abuts on a radially inner portion of the annular protrusion 55 of the rod guide 21 and allows the oil L leaking from the gap between the rod guide 21 and the main shaft portion 33 of the piston rod 31 to flow into the reservoir chamber 13 via the communication hole 56, while functioning as a check valve that restricts the flow of working fluid in the reverse direction.

[0032] The dust lip portion 71 of the seal member 23 passes through the opening 19 of the outer cylinder 14 and protrudes outward from the outer cylinder 14 , that is, outward from the cylinder 15 .

[0033] A bumper cap assembly 5 including a bumper cap 3 and a plate 4 is attached to the shock absorber body 2 configured as described above. The bumper cap assembly 5 is attached to the cylinder 15 so as to cover the opening 19 side thereof, thereby protecting the shock absorber body 2.

[0034] The bumper cap 3 is a one-piece molded product made of metal, and has a bottomed tubular shape having a cylindrical tube portion 85 and a disk-shaped bottom portion 86 extending radially inward from one axial end of the tube portion 85. In other words, the bumper cap 3 has the disk-shaped bottom portion 86 and the cylindrical tube portion 85 extending from the outer circumferential edge of the bottom portion 86 to one side in the axial direction of the bottom portion 86.

[0035] The bottom portion 86 has a hole 87 at its radial center, which penetrates the bottom portion 86 in the axial direction of the bottom portion 86. Thus, the bottom portion 86 has a holed disk shape. The inner diameter of the hole 87 is set to a size that does not interfere with the seal member 23.

[0036] The bottom 86 has a bottom main body portion 91 and a plurality of ribs 92, specifically, three ribs 92 as shown in FIG.

[0037] 4, the bottom main body 91 is flat and has a surface 95 on the opposite side to the tube portion 85 in the axial direction of the bottom 86, and a surface 96 on the tube portion 85 side in the axial direction of the bottom 86. The surface 95 and the surface 96 are both planar and extend perpendicular to the central axis of the bottom 86.

[0038] The rib 92 is formed on a radially inner portion of the bottom 86, and protrudes from the bottom main body portion 91 to one side in the axial direction of the bottom 86. The rib 92 protrudes from the surface portion 95 of the bottom main body portion 91 to the side opposite the tubular portion 85 in the axial direction of the bottom 86. The rib 92 is recessed from the surface portion 96 of the bottom main body portion 91 to the side opposite the tubular portion 85 in the axial direction of the bottom 86.

[0039] The rib 92 has a surface portion 101 on the side opposite to the cylindrical portion 85 in the axial direction of the bottom portion 86, and a surface portion 102 on the cylindrical portion 85 side in the axial direction of the bottom portion 86.

[0040] Both surface portion 101 and surface portion 102 are flat surfaces extending perpendicular to the central axis of bottom portion 86 .

[0041] The rib 92 has a surface portion 104 extending from the outer edge of the surface portion 101 in the radial direction of the bottom portion 86, and a pair of surface portions 105, 105 extending from both side edges of the surface portion 101 in the circumferential direction of the bottom portion 86.

[0042] The surface portion 104 spreads outward from the surface portion 101 in the radial direction of the bottom portion 86, and the further away from the surface portion 101 it is in the radial direction of the bottom portion 86, the closer it gets to the surface portion 102 in the axial direction of the bottom portion 86, and is connected to the surface portion 95 of the bottom main body portion 91. The surface portion 104 is shaped as a part of a tapered surface.

[0043] Each of the pair of face portions 105 extends from face portion 101 toward face portion 102 substantially along the axial direction of bottom portion 86 and is connected to face portion 95 of bottom main body portion 91 .

[0044] The rib 92 has a surface portion 107 extending from the outer edge of the surface portion 102 in the radial direction of the bottom portion 86, and a pair of surface portions 108, 108 extending from both side edges of the surface portion 102 in the circumferential direction of the bottom portion 86.

[0045] The surface portion 107 spreads outward from the surface portion 102 in the radial direction of the bottom portion 86, and the further away from the surface portion 102 it is in the radial direction of the bottom portion 86, the further away it becomes from the surface portion 101 in the axial direction of the bottom portion 86 and connects to the surface portion 96 of the bottom main body portion 91. The surface portion 107 is shaped as a part of a tapered surface.

[0046] Each of the pair of surface portions 108 extends from the surface portion 102 substantially along the axial direction of the bottom portion 86 to the opposite side to the surface portion 101 and is connected to the surface portion 96 of the bottom main body portion 91 .

[0047] As shown in FIG. 3, a plurality of ribs 92 of the same shape are formed on the bottom portion 86 at equal intervals in the circumferential direction of the bottom portion 86.

[0048] 4, the bottom main body 91 has an outer portion 111 located outside the ribs 92 in the radial direction of the bottom 86, and an inner portion 112 that overlaps with the ribs 92 in the radial direction of the bottom 86 and is provided between adjacent ribs 92 in the circumferential direction of the bottom 86. The outer portion 111 is annular. The bottom 86 has the same number of inner portions 112 as the ribs 92, specifically, three locations.

[0049] As described above, the bumper cap 3 has, at the radially inner portion of the bottom 86, the rib 92 that protrudes in the axial direction beyond the outer portion 111 that is on the radially outer side of the bottom 86 of the bottom main body portion 91.

[0050] The plate 4 is a metal one-piece molded product having a disk shape. The plate 4 has a hole 121 that penetrates the plate 4 in the axial direction at its radial center, and is thus a perforated plate. The outer diameter of the plate 4 is equal to the outer diameter of the cylindrical portion 85 of the bumper cap 3.

[0051] The plate 4 has a rib abutment portion 122 on the inner side in the radial direction of the plate 4 and an outer abutment portion 123 on the outer side in the radial direction of the plate 4.

[0052] The rib abutment portion 122 is flat and annular. The radial inside of the rib abutment portion 122 forms the above-mentioned hole 121. The rib abutment portion 122 has a surface portion 125 on one side in the axial direction and a surface portion 126 on the other side. The surface portion 125 and the surface portion 126 are both flat surfaces extending perpendicular to the central axis of the rib abutment portion 122.

[0053] The rib abutment portion 122 is formed with a concave portion 128 that is concave from the surface portion 125 toward the surface portion 126 along the axial direction of the rib abutment portion 122. The concave portion 128 is tapered such that the diameter becomes smaller as the depth increases.

[0054] 3, the rib abutment portion 122 has a plurality of recessed portions 128 of the same shape formed at equal intervals in the circumferential direction of the rib abutment portion 122 and aligned with the radial position of the rib abutment portion 122. The rib abutment portion 122 has the same number of recessed portions 128 as the ribs 92, specifically, three recessed portions 128. As shown in FIG. 4, at least the entire bottom surface of the recessed portion 128 on the rear side in the recessed direction in the radial direction of the plate 4 is aligned with the surface portion 126 of the rib abutment portion 122.

[0055] The outer contact portion 123 has a flat plate shape and an annular shape. The outer contact portion 123 has a surface portion 131 on one side in the axial direction, and a surface portion 132 and a surface portion 133 on both the other sides.

[0056] The surface portion 131 has a planar shape extending perpendicularly to the central axis of the outer contact portion 123. The surface portion 131 is continuous with the surface portion 125 of the rib contact portion 122 and forms the same plane.

[0057] The surface portion 132 has a flat shape extending perpendicular to the central axis of the outer contact portion 123. The surface portion 132 is disposed on the opposite side to the surfaces 125 and 131 than the surface portion 126 of the rib contact portion 122 in the axial direction of the plate 4.

[0058] The surface portion 133 connects the outer peripheral edge of the surface portion 126 of the rib abutment portion 122 and the inner peripheral edge of the surface portion 132 of the outer abutment portion 123. The surface portion 133 is tapered in the axial direction of the plate 4 so that the diameter becomes smaller as it approaches the surface portion 126. The axial length of the surface portion 133 is equal to the axial length of the surface portion 104 of the rib 92, and the taper is equal to the taper of the surface portion 104.

[0059] The outer contact portion 123 is formed with a concave portion 135 that is concave from the surface portion 131 toward the surface portion 132 along the axial direction of the outer contact portion 123. The concave portion 135 is tapered so that the diameter becomes smaller as the depth increases. As shown in FIG. 3, at least the entire bottom surface of the concave portion 135 on the innermost side in the concave direction in the radial direction of the plate 4 is located outside the surface portion 133 of the outer contact portion 123 and is aligned with the surface portion 132 of the outer contact portion 123.

[0060] A plurality of concave portions 135 having the same shape are formed in the outer contact portion 123, aligned with the radial position of the outer contact portion 123. The plurality of concave portions 135 are disposed outward of the plurality of concave portions 128 in the radial direction of the plate 4.

[0061] 3, the multiple recesses 135 are arranged in pairs. The two recesses 135 constituting the same set are provided near a corresponding one of the multiple recesses 128 of the rib abutment portion 122. The two recesses 135 constituting the same set and the recess 128 close to them constitute the same set.

[0062] Of the two concave portions 135 constituting the same set, one concave portion 135 is disposed on one side of the concave portion 128 constituting the same set in the circumferential direction of the plate 4, and the other concave portion 135 is disposed on the opposite side of the concave portion 128 constituting the same set from the one concave portion 135 in the circumferential direction of the plate 4. The two concave portions 135 constituting the same set are disposed at equidistant positions in the circumferential direction of the plate 4 from the concave portions 128 constituting the same set. Thus, the two concave portions 135 constituting the same set are disposed at the remaining corner positions of an isosceles triangle with the concave portions 128 constituting the same set as vertices. In other words, the two concave portions 135 constituting the same set and the one concave portion 135 are disposed to form a truss shape.

[0063] The plate 4 is provided with sets of two recesses 135 and one recess 128, the same number as the number of ribs 92, specifically three sets, at equal intervals in the circumferential direction of the plate 4.

[0064] As shown in Fig. 2, the surface 132 of the outer abutment portion 123 of the plate 4 contacts in surface contact with the surface 95 of the bottom main body portion 91 of the bumper cap 3, and the surface 133 of the outer abutment portion 123 contacts in surface contact with the surfaces 104 of all the ribs 92 of the bumper cap 3. At the same time, the surface 126 of the rib abutment portion 122 of the plate 4 contacts in surface contact with the surfaces 101 of all the ribs 92 of the bumper cap 3. Moreover, at this time, the plate 4 is in a state in which the multiple recesses 128 of the rib abutment portion 122 are aligned in phase with the central positions in the circumferential direction of the rib abutment portion 122 of the surfaces 101 of the ribs 92 that correspond to them one-to-one, as shown in Fig. 3.

[0065] The plate 4 and the bumper cap 3 in the above state are welded, for example, by spot welding, at the positions of all of the recessed portions 128 and all of the recessed portions 135 of the plate 4, as shown in Fig. 2. As a result, welds 141 are formed by welding the rib abutment portions 122 and the ribs 92 to each other at the positions of all of the recessed portions 128 of the plate 4. Also, welds 142 are formed by welding the outer abutment portions 123 and the outer portion 111 of the bottom main body portion 91 to each other at the positions of all of the recessed portions 135 of the plate 4. In this manner, the plate 4 and the bumper cap 3 are integrally joined by welding to form the bumper cap assembly 5.

[0066] Therefore, in the bumper cap assembly 5, a plurality of welds 141, which are formed by welding the rib abutment portion 122 of the plate 4 to the rib 92 of the bumper cap 3, are formed at equal intervals in the circumferential direction of the bumper cap assembly 5, with their positions aligned in the radial direction of the bumper cap assembly 5. Moreover, at this time, the plurality of welds 141 are each aligned in phase with the central position in the circumferential direction of the rib abutment portion 122 of the rib 92 which corresponds to it one-to-one. The bumper cap assembly 5 has the same number of welds 141 as the ribs 92, specifically three locations.

[0067] Furthermore, in the bumper cap assembly 5, a plurality of welds 142 are formed by welding the outer abutment portion 123 of the plate 4 to the outer portion 111 of the bottom main body portion 91 of the bumper cap 3, and are aligned in the radial direction of the bumper cap assembly 5. In the bumper cap assembly 5, the plurality of welds 142 are disposed outward of the plurality of welds 141 in the radial direction of the bumper cap assembly 5.

[0068] The multiple welds 142 are arranged in pairs. Two welds 142 constituting the same set are provided near a corresponding one of the multiple welds 141. Two welds 142 constituting the same set and one weld 141 close to them constitute the same set.

[0069] Of the two welds 142 constituting the same set, one weld 142 is disposed on one side of the weld 141 constituting the same set in the circumferential direction of the bumper cap assembly 5, and the other weld 142 is disposed on the opposite side of the weld 141 constituting the same set from the one weld 142 in the circumferential direction of the bumper cap assembly 5. The two welds 142 constituting the same set are disposed at positions equidistant from the weld 141 constituting the same set in the circumferential direction of the bumper cap assembly 5. Thus, the two welds 142 constituting the same set are disposed at the remaining corner positions of an isosceles triangle with the weld 141 constituting the same set as the apex. In other words, the two welds 142 constituting the same set and the one weld 141 are disposed to form a truss shape.

[0070] The bumper cap assembly 5 has the same number of sets of two welded portions 142 and one welded portion 141 as the number of ribs 92, specifically, three sets.

[0071] The bumper cap assembly 5 having the above configuration is fitted over the radially outer side of the body portion 17 by inserting the main shaft portion 33 of the piston rod 31 of the shock absorber body 2 into the radially inner side of the hole portion 87 of the bumper cap 3 and the hole portion 121 of the plate 4, and inserting the body portion 17 of the outer cylinder 14 of the shock absorber body 2 into the radially inner side of the tubular portion 85 of the bumper cap 3. At this time, the bottom body portion 91 of the bottom portion 86 of the bumper cap 3 is brought into contact with the locking portion 24 of the outer cylinder 14 of the shock absorber body 2 at the surface portion 96. In this state, the bumper cap assembly 5 is fixed to the outer cylinder 14 of the shock absorber body 2 by, for example, crimping a plurality of circumferential points of the tubular portion 85 of the bumper cap 3 radially inward.

[0072] In the bumper cap assembly 5 thus attached to the shock absorber body 2, the bumper cap 3 and the plate 4 are provided at the axial end of the side from which the piston rod 31 of the cylinder 15 of the shock absorber body 2 protrudes. In addition, in the bumper cap assembly 5, the bumper cap 3 has a bottom portion 86 having a hole portion 87 through which the piston rod 31 of the shock absorber body 2 can be inserted, and a tubular portion 85 covering the radial outer periphery of the cylinder 15 of the shock absorber body 2. In addition, in the bumper cap assembly 5, the plate 4 has a hole portion 121 through which the piston rod 31 of the shock absorber body 2 can be inserted.

[0073] The shock absorber 1 configured by mounting the bumper cap assembly 5 to the shock absorber main body 2 in this manner is assembled to the vehicle body side at the piston rod 31 and to the wheel side at the mounting eye 46, with the portion of the piston rod 31 protruding from the cylinder 15 facing upward and the mounting eye 46 facing downward. At this time, a bellows-shaped rubber bump rubber 151 is disposed between the bumper cap assembly 5 and the vehicle body, with the piston rod 31 inserted inside. The bellows-shaped bump rubber 151 surrounds the hole 121 on the radial outside and abuts against the plate 4. The bumper cap assembly 5 protects the seal member 23 from the bump rubber 151 in the shock absorber 1.

[0074] As described above, in the shock absorber 1, the plate 4 has the outer abutment portion 123 that abuts against the outer portion 111 of the bumper cap 3 and the rib abutment portion 122 that abuts against the rib 92 of the bumper cap 3, and is fixed to the bumper cap 3. In addition, the shock absorber 1 has a plurality of ribs 92, and the rib abutment portion 122 is fixed by a welded portion 141 at one location for each of the plurality of ribs 92, and the outer abutment portion 123 is fixed by a plurality of welded portions 142 at a position in the circumferential direction of the bottom portion 86 that is different from the welding position of the rib abutment portion 122. In addition, in the shock absorber 1, the plurality of welded portions 142 of the outer abutment portion 123 are provided at two locations with respect to the one welded portion 141 formed for each of the plurality of ribs 92, and form a truss shape with the one welded portion 141 of the rib 92.

[0075] The above-mentioned Patent Document 1 discloses a shock absorber in which a plate is provided on the upper surface of a bumper cap. Patent Document 2 discloses a shock absorber in which a plate having an uneven surface is provided on the upper surface of an outer cylinder. There is a demand for improving the load-bearing performance of the cylinder in the shock absorber. In particular, the weight of electric vehicles tends to increase, and there is a high demand for improving the load-bearing performance of the shock absorber. In order to improve the load-bearing performance, the shock absorber will be increased in weight and size, but from the viewpoint of the constraints on the installation space on the vehicle and the suppression of the increase in vehicle weight, it is desired to improve the load-bearing performance while suppressing the increase in weight and size of the shock absorber.

[0076] In the shock absorber 1 of the first embodiment, the bumper cap 3 has a rib 92 at the radially inner portion of the bottom 86 that protrudes in the axial direction beyond the outer portion 111 on the radially outer side of the bottom 86. The shock absorber 1 includes a plate 4 that has an outer abutment portion 123 that abuts against the outer portion 111 of the bottom 86 of the bumper cap 3 and a rib abutment portion 122 that abuts against the rib 92 of the bottom 86 of the bumper cap 3 and is fixed to the bumper cap 3. Thus, the shock absorber 1 can improve the strength of the bottom 86 of the bumper cap 3 and can be further reinforced by the plate 4. Therefore, the shock absorber 1 can improve the load-bearing performance while suppressing an increase in weight and size.

[0077] Furthermore, the shock absorber 1 is provided with a plurality of ribs 92, the rib abutment portions 122 are fixed by one welded portion 141 for each of the plurality of ribs 92, and the outer abutment portions 123 are fixed by a plurality of welded portions 142 at positions in the circumferential direction of the bottom portion 86 that are different from the welding positions of the rib abutment portions 122. By arranging the welded portions 141, 142 in this manner, the shock absorber 1 can effectively release the input load to the plate 4 to the bumper cap 3. Therefore, the shock absorber 1 can further improve the load-bearing performance while further suppressing increases in weight and size.

[0078] Furthermore, in the shock absorber 1, the multiple welds 142 of the outer abutment portion 123 are provided in two places with respect to one weld 141 formed for each of the multiple ribs 92, forming a truss shape with the single weld 141 of the rib 92. By arranging the welds 141, 142 in this manner, the shock absorber 1 can control the moment load to a linear load. Therefore, the shock absorber 1 can further improve the load-bearing performance while further suppressing increases in weight and size.

[0079] [Second embodiment] Next, the second embodiment will be described focusing on the differences from the first embodiment with reference to Fig. 5. The same parts as the first embodiment will be designated by the same names and symbols.

[0080] In the second embodiment, a bumper cap assembly 5A shown in FIG. 5, which is partially different from the bumper cap assembly 5 of the first embodiment, is used instead of the bumper cap assembly 5.

[0081] The bumper cap assembly 5A has a bumper cap 3 similar to that of the bumper cap assembly 5, but has a plate 4A which is partially different from the plate 4 in place of the plate 4. The plate 4A has a first plate 171 and a second plate 172 which is separate from the first plate 171.

[0082] The first plate 171 is a one-piece molded metal product having a disk shape. The first plate 171 has a hole 121, similar to the plate 4, penetrating the first plate 171 in the axial direction at its radial center, and has a hole shape. The first plate 171 has an outer diameter equal to the outer diameter of the cylindrical portion 85 of the bumper cap 3.

[0083] The first plate 171 is provided on its radially inner side with a rib abutment portion 122 similar to that of the plate 4, and is provided on its radially outer side with an outer annular portion 175 that is partially different from the outer abutment portion 123. The outer annular portion 175 is flat and annular.

[0084] The outer annular portion 175 has a surface 131 similar to the outer abutment portion 123 on one side in the axial direction, and a surface 177 on the other side in the axial direction. The surface 177 is continuous with and in the same plane as the surface 126 of the rib abutment portion 122. The outer annular portion 175 has a recessed portion 135 similar to the outer abutment portion 123 formed at the same position as the outer abutment portion 123.

[0085] The second plate 172 is an integrally molded metal product, and has a holed disk shape. The second plate 172 is flat. The outer diameter of the second plate 172 is equal to the outer diameter of the cylindrical portion 85 of the bumper cap 3, and the inner diameter of the second plate 172 is equal to the inner diameter of the surface portion 95 of the bumper cap 3. The thickness, i.e., the axial length of the second plate 172 is equal to the axial length of the surface portion 104 of the rib 92.

[0086] The second plate 172 has a surface portion 181 on one axial side and a surface portion 182 on the other axial side. The surface portion 181 and the surface portion 182 are both flat surfaces extending perpendicular to the central axis of the second plate 172.

[0087] In the plate 4A having the above-described first plate 171 and second plate 172, the second plate 172 abuts in surface contact at the surface portion 182 against the surface portion 95 of the bottom main body portion 91 of the bumper cap 3. That is, the second plate 172 abuts against the outer portion 111 of the bottom main body portion 91. At that time, all of the ribs 92 of the bumper cap 3 are inserted into the radially inner side of the second plate 172.

[0088] In addition, the first plate 171 of the plate 4A abuts in surface contact with the surfaces 101 of all the ribs 92 of the bumper cap 3 at the surfaces 126 of the rib abutment portion 122. At the same time, the plate 4A abuts in surface contact with the surfaces 181 of the second plate 172 at the surfaces 177 of the outer annular portion 175. Moreover, at this time, the first plate 171 is in a state in which the multiple recessed portions 128 of the rib abutment portion 122 are aligned in phase with central positions in the circumferential direction of the rib abutment portion 122 of the surfaces 101 of the ribs 92 that correspond one-to-one to each other.

[0089] In this state, at least the entire bottom surface of the recessed portion 135 of the first plate 171 on the inner side in the radial direction of the first plate 171 in the recessed direction is positioned to overlap the surfaces 181 and 182 of the second plate 172 .

[0090] In the plate 4A, the outer annular portion 175 of the first plate 171 and the second plate 172 form an outer abutment portion 123A that abuts against the outer portion 111 of the bumper cap 3.

[0091] The plate 4A and the bumper cap 3 in the above state are welded, for example, by spot welding, at the positions of all the concave portions 128 and all the concave portions 135 of the first plate 171. As a result, a welded portion 141 is formed by welding the rib abutment portion 122 and the rib 92 at the positions of all the concave portions 128 of the rib abutment portion 122 of the first plate 171. Also, a welded portion 142A is formed by welding the outer annular portion 175 of the first plate 171, the second plate 172, and the outer portion 111 of the bottom main body portion 91 at the positions of all the concave portions 135 of the first plate 171. In other words, a welded portion 142A is formed by welding the outer abutment portion 123A of the plate 4A and the outer portion 111 of the bottom main body portion 91 of the bumper cap 3 at the positions of all the concave portions 135 of the first plate 171. The plate 4A having the first plate 171 and the second plate 172 and the bumper cap 3 are integrally joined by welding to form the bumper cap assembly 5A.

[0092] Therefore, in the bumper cap assembly 5A, a plurality of welds 141, which are formed by welding the rib abutment portion 122 of the plate 4A to the rib 92 of the bumper cap 3, are formed at equal intervals in the circumferential direction of the bumper cap assembly 5A, with their positions aligned in the radial direction of the bumper cap assembly 5A. Moreover, at this time, the plurality of welds 141 are each aligned in phase with the central position in the circumferential direction of the rib abutment portion 122 of the rib 92 which corresponds to it one-to-one. The bumper cap assembly 5A has the same number of welds 141A as the number of ribs 92, specifically three locations.

[0093] Furthermore, in the bumper cap assembly 5A, a plurality of welds 142A are formed by welding the outer contact portion 123A of the plate 4A to the bottom body portion 91 of the bumper cap 3, and are aligned in the radial direction of the bumper cap assembly 5A. In the bumper cap assembly 5A, the plurality of welds 142A are disposed on the outer side of the plurality of welds 141 in the radial direction of the bumper cap assembly 5A.

[0094] The multiple welded portions 142A are arranged in pairs. Two welded portions 142A constituting the same pair are provided near a corresponding one of the multiple welded portions 141. Two welded portions 142A constituting the same pair and a welded portion 141 close to them constitute the same pair.

[0095] Of the two welds 142A constituting the same set, one weld 142A is disposed on one side of the weld 141 constituting the same set in the circumferential direction of the bumper cap assembly 5A, and the other weld 142A is disposed on the opposite side of the weld 141 constituting the same set to the one weld 142A in the circumferential direction of the bumper cap assembly 5A. The two welds 142A constituting the same set are disposed at equidistant positions in the circumferential direction of the bumper cap assembly 5A from the weld 141 constituting the same set. Thus, the two welds 142A constituting the same set are disposed at the remaining corner positions of an isosceles triangle with the weld 141 constituting the same set as the apex. In other words, the two welds 142A constituting the same set and the one weld 141 are disposed to form a truss shape.

[0096] The bumper cap assembly 5A has the same number of sets of two welded portions 142A and one welded portion 141 as the number of ribs 92, specifically, three sets.

[0097] The bumper cap assembly 5A having the above configuration is fitted over the radially outer side of the body portion 17 by inserting the main shaft portion 33 of the piston rod 31 of the shock absorber body 2 shown in FIG. 2 into the radially inner side of the hole portion 87 of the bumper cap 3 and the hole portion 121 of the plate 4A, and inserting the body portion 17 of the outer cylinder 14 of the shock absorber body 2 into the radially inner side of the tubular portion 85 of the bumper cap 3. At this time, the bottom body portion 91 of the bottom portion 86 of the bumper cap 3 is brought into contact with the locking portion 24 of the outer cylinder 14 of the shock absorber body 2 at the surface portion 96. In this state, the bumper cap assembly 5A is fixed to the outer cylinder 14 of the shock absorber body 2 by, for example, crimping a plurality of circumferential points of the tubular portion 85 of the bumper cap 3 radially inward.

[0098] In the bumper cap assembly 5A thus attached to the shock absorber body 2, the bumper cap 3 and the plate 4A are provided at the axial end of the side from which the piston rod 31 of the cylinder 15 of the shock absorber body 2 protrudes. In addition, in the bumper cap assembly 5A, the bumper cap 3 has a bottom portion 86 having a hole portion 87 through which the piston rod 31 of the shock absorber body 2 can be inserted, and a tubular portion 85 covering the radial outer periphery of the cylinder 15 of the shock absorber body 2. In addition, in the bumper cap assembly 5A, the plate 4A has a hole portion 121 through which the piston rod 31 of the shock absorber body 2 can be inserted.

[0099] As described above, in the second embodiment, the plate 4A has an outer abutment portion 123A that abuts against the outer portion 111 of the bumper cap 3 and a rib abutment portion 122 that abuts against the rib 92 of the bumper cap 3, and is fixed to the bumper cap 3. In the second embodiment, a plurality of ribs 92 are provided, and the rib abutment portion 122 is fixed by a welded portion 141 at one location for each of the plurality of ribs 92, and the outer abutment portion 123A is fixed by a plurality of welded portions 142A at a position in the circumferential direction of the bottom portion 86 that is different from the welding position of the rib abutment portion 122. In the second embodiment, the plurality of welded portions 142A of the outer abutment portion 123A are provided at two locations with respect to the one welded portion 141 formed for each of the plurality of ribs 92, and form a truss shape with the one welded portion 141 of the rib 92. In the second embodiment, the plate 4A has a first plate 171 that abuts against the rib 92 and a second plate 172 that abuts against the outer portion 111.

[0100] In the second embodiment, the bumper cap 3 has a rib 92 that protrudes in the axial direction from the outer side part 111 on the outer side of the bottom part 86 in the radial direction at the inner side part of the bottom part 86 in the radial direction. In addition, in the second embodiment, the bumper cap 3 includes a plate 4A having an outer abutment part 123A that abuts against the outer side part 111 of the bottom part 86 of the bumper cap 3 and a rib abutment part 122 that abuts against the rib 92 of the bottom part 86 of the bumper cap 3 and is fixed to the bumper cap 3. Therefore, in the second embodiment, the strength of the bottom part 86 of the bumper cap 3 can be improved, and further reinforced by the plate 4A. Therefore, in the second embodiment, it is possible to improve the load-bearing performance while suppressing an increase in weight and size.

[0101] In the second embodiment, a plurality of ribs 92 are provided, the rib abutment portions 122 are fixed at one weld 141 for each of the plurality of ribs 92, and the outer abutment portion 123A is fixed at a plurality of welds 142A at a position in the circumferential direction of the bottom portion 86 different from the welding position of the rib abutment portion 122. In the second embodiment, by arranging the welds 141, 142A in this manner, the input load to the plate 4A can be effectively released to the bumper cap 3. Therefore, in the second embodiment, it is possible to further improve the load-bearing performance while further suppressing an increase in weight and size.

[0102] In the second embodiment, the multiple welds 142A of the outer contact portion 123A are provided in two places in comparison with the single weld 141 formed for each of the multiple ribs 92, and form a truss shape with the single weld 141 of the rib 92. In the second embodiment, by arranging the welds 141, 142A in this way, it is possible to control the moment load to a linear load. Therefore, in the second embodiment, it is possible to further improve the load-bearing performance while further suppressing the increase in weight and size.

[0103] In the second embodiment, the plate 4A has a first plate 171 that contacts the rib 92 and a second plate 172 that contacts the outer portion 111. As a result, when the height of the rib 92 in the axial direction of the bumper cap 3 varies, for example, the thickness of the second plate 172 can be varied while leaving the first plate 171 unchanged. This makes it possible to suppress an increase in costs.

[0104] [Third embodiment] Next, the third embodiment will be described with a focus on differences from the first embodiment, mainly with reference to Fig. 6. Note that parts common to the first embodiment will be designated by the same names and reference numerals.

[0105] In the third embodiment, a bumper cap assembly 5B shown in FIG. 6, which is partially different from the bumper cap assembly 5 of the first embodiment, is used instead of the bumper cap assembly 5.

[0106] The bumper cap assembly 5B has a bumper cap 3 similar to that of the bumper cap assembly 5, but has a plate 4B different from the plate 4 instead of the plate 4. The plate 4B has a first plate 201 and a second plate 202 separate from the first plate 201.

[0107] The first plate 201 is a flat, one-piece metal molded product. The first plate 201 is sized to be able to be placed in one of the concave ribs 92 of the bumper cap 3. The thickness of the first plate 201 is equal to the axial length of the surface portion 107 of the rib 92.

[0108] The first plate 201 has a surface portion 205 on one axial side and a surface portion 206 on the other axial side. The surface portion 205 and the surface portion 206 are both flat surfaces extending perpendicular to the central axis of the first plate 201.

[0109] The plate 4B has the first plates 201 in the same number as the ribs 92, specifically, three.

[0110] The second plate 202 is a metal integrally molded product having a disk shape. The second plate 202 has a hole 211 that penetrates the second plate 202 in the axial direction at its radial center, and has a holed plate shape. The diameter of the hole 211 is equal to the diameter of the hole 87 of the bumper cap 3. The outer diameter of the second plate 202 is equal to the outer diameter of the surface portion 96 of the bumper cap 3.

[0111] The second plate 202 has an inner annular portion 221 on the inner side in the radial direction of the second plate 202, and an outer abutment portion 123B on the outer side in the radial direction of the second plate 202.

[0112] The inner annular portion 221 is flat and annular. The inner radial surface of the inner annular portion 221 is the hole 211. The inner annular portion 221 has a surface 225 on one side in the axial direction and a surface 226 on the other side. The surface 225 and the surface 226 are both planar and extend perpendicular to the central axis of the inner annular portion 221.

[0113] Inner annular portion 221 is formed with concave portion 128B recessed from surface portion 226 toward surface portion 225 along the axial direction of inner annular portion 221. Concave portion 128B has a tapered shape in which the diameter decreases as the depth increases.

[0114] In the inner annular portion 221, a plurality of recessed portions 128B of the same shape are formed at equal intervals in the circumferential direction of the inner annular portion 221, and are aligned in the radial direction of the inner annular portion 221. The inner annular portion 221 has the same number of recessed portions 128B as the ribs 92, specifically, three locations. In the radial direction of the inner annular portion 221, at least the entire bottom surface on the far side in the recessed direction is aligned with the surface portion 225 of the inner annular portion 221.

[0115] The outer contact portion 123B is flat and annular in shape. The outer contact portion 123B has a surface portion 231 on one side in the axial direction and a surface portion 232 on the other side.

[0116] Both the surface portion 231 and the surface portion 232 are planar and extend perpendicular to the central axis of the outer abutment portion 123B. The surface portion 231 is continuous with and in the same plane as the surface portion 225 of the inner annular portion 221. The surface portion 232 is continuous with and in the same plane as the surface portion 226 of the inner annular portion 221.

[0117] The outer contact portion 123B is formed with a concave portion 135B that is concave from the surface portion 232 toward the surface portion 1231 along the axial direction of the outer contact portion 123B. The concave portion 135B has a tapered shape that becomes smaller in diameter as it becomes deeper.

[0118] A plurality of recesses 135B having the same shape are formed in the outer contact portion 123B, and are aligned with each other in the radial direction of the outer contact portion 123B. The plurality of recesses 135B are disposed on the outer side of the second plate 202 in the radial direction than the plurality of recesses 128B.

[0119] The multiple recessed portions 135B are arranged in pairs. The two recessed portions 135B constituting the same pair are provided near a corresponding one of the multiple recessed portions 128B of the inner annular portion 221. The two recessed portions 135B constituting the same pair and the recessed portion 128B close to them constitute the same pair.

[0120] Of the two concave portions 135B constituting the same set, one concave portion 135B is disposed on one side of the concave portion 128B constituting the same set in the circumferential direction of the second plate 202, and the other concave portion 135B is disposed on the opposite side of the concave portion 128B constituting the same set in the circumferential direction of the second plate 202. The two concave portions 135B constituting the same set are disposed at equidistant positions in the circumferential direction of the second plate 202 from the concave portions 128B constituting the same set. Thus, the two concave portions 135B constituting the same set are disposed at the remaining corner positions of an isosceles triangle with the concave portions 128B constituting the same set as the vertices. In other words, the two concave portions 135B constituting the same set and the one concave portion 135B are disposed to form a truss shape.

[0121] The second plate 202 is provided with sets of two recesses 135B and one recess 128B at the same number as the number of ribs 92, specifically three sets, at equal intervals in the circumferential direction of the second plate 202.

[0122] In the plate 4B having the above-described multiple first plates 201 and one second plate 202, the multiple first plates 201 are in surface contact with the surfaces 102 of the ribs 92 of the bumper cap 3 that correspond to them one-to-one at the surfaces 205. The first plates 201 are arranged in this manner on all the ribs 92 of the bumper cap 3.

[0123] In addition, the second plate 202 of the plate 4B abuts on the surfaces 206 of all the first plates 201 at the surfaces 225 of the inner annular portion 221, and also abuts in surface contact with the surfaces 96 of the bottom portion 86 of the bumper cap 3. At the same time, the outer abutment portion 123B of the plate 4B abuts in surface contact with the surfaces 96 of the bottom portion 86 of the bumper cap 3 at the surfaces 231. Moreover, at this time, the second plate 202 is in a state in which the multiple recessed portions 128B of the inner annular portion 221 are each in phase with the central positions in the circumferential direction of the bottom portion 86 of the surfaces 206 of the first plate 201 that correspond to them one-to-one.

[0124] In this state, at least the entire bottom surface of the recessed portion 135B of the second plate 202 on the innermost side in the recessed direction is positioned to overlap the outer portion 111 of the bottom portion 86 in the radial direction of the second plate 202.

[0125] In the plate 4B, the inner annular portion 221 of the first plate 201 and the second plate 202 constitute a rib abutment portion 122B that abuts against the rib 92 of the bumper cap 3.

[0126] The plate 4B and the bumper cap 3 in the above state are welded, for example, by spot welding, at the positions of all the concave portions 128B and all the concave portions 135B of the second plate 202. As a result, welded portions 141B are formed by welding the inner annular portion 221, the first plate 201, and the rib 92 to the positions of all the concave portions 128B of the inner annular portion 221 of the second plate 202. In other words, welded portions 141B are formed by welding the rib abutment portion 122B of the plate 4B and the rib 92 of the bumper cap 3 to the positions of all the concave portions 128B of the second plate 202. Also, welded portions 142B are formed by welding the outer abutment portion 123B of the second plate 202 and the outer portion 111 of the bumper cap 3 to the positions of all the concave portions 135B of the second plate 202. The plate 4B having the plurality of first plates 201 and second plates 202 in this manner and the bumper cap 3 are integrally joined by welding to form a bumper cap assembly 5B.

[0127] Therefore, in the bumper cap assembly 5B, a plurality of welded portions 141B, which are formed by welding the rib abutment portion 122B of the plate 4B to the rib 92 of the bumper cap 3, are formed at equal intervals in the circumferential direction of the bumper cap assembly 5B, with their positions aligned in the radial direction of the bumper cap assembly 5B. Moreover, at this time, the phases of the plurality of welded portions 141B are aligned with the central positions in the circumferential direction of the rib abutment portions 122 of the ribs 92 which correspond to them one-to-one. The bumper cap assembly 5B has the same number of welded portions 141B as the ribs 92, specifically, three locations.

[0128] Furthermore, in the bumper cap assembly 5B, a plurality of welded portions 142B are formed by welding the outer contact portion 123B of the plate 4B to the bottom main body portion 91 of the bumper cap 3, and are aligned in the radial direction of the bumper cap assembly 5B. In the bumper cap assembly 5B, the plurality of welded portions 142B are disposed on the outer side in the radial direction of the bumper cap assembly 5B than the plurality of welded portions 141B.

[0129] The multiple welded portions 142B are arranged in pairs. Two welded portions 142B that make up the same pair are provided near a corresponding one of the multiple welded portions 141B. Two welded portions 142B that make up the same pair and one welded portion 141B close to them make up the same pair.

[0130] Of the two welded portions 142B constituting the same set, one welded portion 142B is disposed on one side of the welded portion 141B constituting the same set in the circumferential direction of the bumper cap assembly 5B, and the other welded portion 142B is disposed on the opposite side of the welded portion 141B constituting the same set in the circumferential direction of the bumper cap assembly 5B. The two welded portions 142B constituting the same set are disposed at equidistant positions in the circumferential direction of the bumper cap assembly 5B from the welded portion 141B constituting the same set. Thus, the two welded portions 142B constituting the same set are disposed at the remaining corner positions of an isosceles triangle with the welded portion 141B constituting the same set as the apex. In other words, the two welded portions 142B constituting the same set and the one welded portion 141B are disposed to form a truss shape.

[0131] The bumper cap assembly 5B has the same number of sets of two welded portions 142B and one welded portion 141B as the number of ribs 92, specifically, three sets.

[0132] The bumper cap assembly 5B having the above configuration is fitted over the radially outer side of the body portion 17 by inserting the main shaft portion 33 of the piston rod 31 of the shock absorber body 2 shown in FIG. 2 into the radially inner side of the hole portion 87 of the bumper cap 3 and the hole portion 211 of the plate 4B, and inserting the body portion 17 of the outer cylinder 14 of the shock absorber body 2 into the radially inner side of the tubular portion 85 of the bumper cap 3. At this time, the second plate 202 of the plate 4B of the bumper cap assembly 5B is brought into contact with the locking portion 24 of the outer cylinder 14 of the shock absorber body 2 at the surface portion 232. In this state, the bumper cap assembly 5B is fixed to the outer cylinder 14 of the shock absorber body 2 by, for example, crimping a plurality of circumferential points of the tubular portion 85 of the bumper cap 3 radially inward.

[0133] In the bumper cap assembly 5B thus attached to the shock absorber body 2, the bumper cap 3 and the plate 4B are provided at the axial end of the side from which the piston rod 31 of the cylinder 15 of the shock absorber body 2 protrudes. In addition, in the bumper cap assembly 5B, the bumper cap 3 has a bottom portion 86 having a hole portion 87 through which the piston rod 31 of the shock absorber body 2 can be inserted, and a tubular portion 85 covering the radial outer periphery of the cylinder 15 of the shock absorber body 2. In addition, in the bumper cap assembly 5B, the second plate 202 of the plate 4B has a hole portion 211 through which the piston rod 31 of the shock absorber body 2 can be inserted.

[0134] As described above, in the third embodiment, the plate 4B has an outer abutment portion 123B that abuts against the outer portion 111 of the bumper cap 3 and a rib abutment portion 122B that abuts against the rib 92 of the bumper cap 3, and is fixed to the bumper cap 3. In the third embodiment, a plurality of ribs 92 are provided, and the rib abutment portion 122B is fixed to each of the plurality of ribs 92 by a single welded portion 141B, and the outer abutment portion 123B is fixed to each of the plurality of ribs 92 by a plurality of welded portions 142B at positions different from the welding positions of the rib abutment portions 122 in the circumferential direction of the bottom portion 86. In the third embodiment, the plurality of welded portions 142B of the outer abutment portion 123B are provided at two positions with respect to the single welded portion 141B formed for each of the plurality of ribs 92, and form a truss shape with the single welded portion 141B of the rib 92. In the third embodiment, the plate 4B has a first plate 201 that abuts against the rib 92 and a second plate 202 that abuts against the outer portion 111.

[0135] In the third embodiment, the bumper cap 3 has a rib 92 that protrudes in the axial direction from the outer side part 111 on the outer side of the bottom part 86 in the radial direction at the inner side part of the bottom part 86 in the radial direction. In addition, in the third embodiment, the bumper cap 3 is provided with a plate 4B having an outer abutment part 123B that abuts against the outer side part 111 of the bottom part 86 of the bumper cap 3 and a rib abutment part 122B that abuts against the rib 92 of the bottom part 86 of the bumper cap 3 and fixed to the bumper cap 3. As a result, in the third embodiment, the strength of the bottom part 86 of the bumper cap 3 can be improved, and further reinforced by the plate 4B. Therefore, in the third embodiment, it is possible to improve the load-bearing performance while suppressing an increase in weight and size.

[0136] In the third embodiment, a plurality of ribs 92 are provided, the rib abutment portions 122B are fixed to each of the plurality of ribs 92 by one welded portion 141B, and the outer abutment portions 123B are fixed by a plurality of welded portions 142B at positions in the circumferential direction of the bottom portion 86 that are different from the welding positions of the rib abutment portions 122B. In the third embodiment, by arranging the welded portions 141B, 142B in this manner, the input load to the plate 4B can be effectively released to the bumper cap 3. Therefore, in the third embodiment, it is possible to further improve the load-bearing performance while further suppressing increases in weight and size.

[0137] In the third embodiment, the outer contact portion 123B has two welds 142B, one for each of the ribs 92, and these welds 141B form a truss shape with the weld 141B at one of the ribs 92. In the third embodiment, the welds 141B and 142B are arranged in this manner, so that the moment load can be controlled to a linear load. Therefore, in the third embodiment, it is possible to further improve the load-bearing performance while further suppressing the increase in weight and size.

[0138] In the third embodiment, the plate 4B has a first plate 201 that contacts the rib 92 and a second plate 202 that contacts the outer portion 111. As a result, when the height of the rib 92 in the axial direction of the bumper cap 3 varies, for example, the thickness of the first plate 201 can be varied while leaving the second plate 202 unchanged. This makes it possible to suppress an increase in costs.

[0139] In the third embodiment, the rib 92 may be formed in a single continuous annular shape around the entire circumference of the bumper cap 3, and the first plate 201 may be formed as a single annular part.

[0140] [Fourth embodiment] Next, the fourth embodiment will be described with a focus on differences from the first embodiment, mainly with reference to Fig. 7. Note that parts common to the first embodiment will be designated by the same names and reference numerals.

[0141] In the fourth embodiment, a bumper cap assembly 5C shown in FIG. 7, which is partially different from the bumper cap assembly 5 of the first embodiment, is used instead of the bumper cap assembly 5.

[0142] The bumper cap assembly 5C has a bumper cap 3 similar to that of the bumper cap assembly 5, but has a plate 4C different from the plate 4 instead of the plate 4.

[0143] The plate 4C is an annular member made of metal and includes a disk-shaped portion 251, a cylindrical portion 252, and a locking portion 253.

[0144] The disk-shaped portion 251 is a disk having a hole. The tubular portion 252 is cylindrical and extends from an inner peripheral edge of the disk-shaped portion 251 to one side in the axial direction of the disk-shaped portion 251. The locking portion 253 extends outward in the radial direction of the tubular portion 252 from an edge of the tubular portion 252 on the opposite side to the disk-shaped portion 251 in the axial direction.

[0145] The plate 4C has a hole 255 that penetrates the plate 4C in the axial direction on the radially inner side of the cylindrical portion 252. The outer diameter of the plate 4C is equal to the outer diameter of the surface portion 96 of the bumper cap 3. The inner diameter of the hole 255 is set to a size that does not interfere with the seal member 23.

[0146] The disk-shaped portion 251 has a base plate portion 261 and a rib abutment portion 122C that protrudes from the radially inner side of the base plate portion 261 to the same side as the cylindrical portion 252 in the axial direction of the base plate portion 261. The cylindrical portion 252 and the rib abutment portion 122C are continuous in the radial direction of the cylindrical portion 252.

[0147] The substrate portion 261 has a surface portion 265 on one side in the axial direction, and a surface portion 266 on the other side in the axial direction. The surface portions 265 and 266 are both flat surfaces extending perpendicular to the central axis of the substrate portion 261.

[0148] The rib contact portion 122C is provided on the radially inner side of the plate 4C. The rib contact portion 122C protrudes from a surface portion 265 of the base plate portion 261. An outer contact portion 123C is located on the radially outer side of the rib contact portion 122C of the base plate portion 261. The outer contact portion 123C contacts the outer portion 111 of the bumper cap 3.

[0149] The rib abutment portion 122C has a surface portion 271 and a surface portion 272 on the opposite side to the surface portion 266 in the axial direction of the disc-shaped portion 251. The rib abutment portion 122C has the surface portion 271 on the inner side from the middle position in the radial direction of the disc-shaped portion 251, and the surface portion 272 on the outer side in the radial direction of the disc-shaped portion 251.

[0150] The surface portion 271 has a flat shape extending perpendicular to the central axis of the disc-shaped portion 251. The surface portion 272 is inclined so as to approach the surface portion 265 of the base portion 261 the further away from the surface portion 271 in the radial direction of the disc-shaped portion 251, and merges with the surface portion 265.

[0151] The rib abutment portion 122C enters the concave rib 92 of the bumper cap 3, abuts against the surface 102 of the rib 92 at a surface 271, and abuts against the surface 107 of the rib 92 at a surface 272.

[0152] A plurality of rib abutment portions 122C are formed on the disc-shaped portion 251 at equal intervals in the circumferential direction of the disc-shaped portion 251. The disc-shaped portion 251 has the same number of rib abutment portions 122C as the number of ribs 92, specifically, three portions.

[0153] Before the plate 4C is attached to the bumper cap 3, the locking portion 253 is not formed, and the cylindrical portion 252 is accordingly long in the axial direction. In this state, the cylindrical portion 252 of the plate 4C is inserted into the hole 87 of the bumper cap 3 from the cylindrical portion 85 side in the axial direction. Then, the surface 265 of the outer abutment portion 123C of the plate 4C abuts in surface contact with the surface 96 of the outer portion 111 of the bumper cap 3, and the multiple rib abutment portions 122C abut in surface contact with the surface 102 of the rib 92 that corresponds to them in one-to-one correspondence at the surface 271, and abut in surface contact with the surface 107 of the rib 92 that corresponds to them in one-to-one correspondence at the surface 272.

[0154] From the above state, the portion of the cylindrical portion 252 protruding from the bumper cap 3 is crimped radially outward and plastically deformed to form the locking portion 253. As a result, the locking portion 253 is pressed against the surface portions 101 of all the ribs 92, and all the ribs 92 are sandwiched between the locking portion 253 and the rib abutment portion 122C. In this manner, the plate 4C and the bumper cap 3 are integrally joined to form the bumper cap assembly 5C.

[0155] The bumper cap assembly 5C having the above configuration is fitted over the radially outer side of the body portion 17 by inserting the main shaft portion 33 of the piston rod 31 of the shock absorber body 2 shown in FIG. 2 into the radially inner side of the hole portion 87 of the bumper cap 3 and the hole portion 255 of the plate 4C, and inserting the body portion 17 of the outer cylinder 14 of the shock absorber body 2 into the radially inner side of the cylinder portion 85 of the bumper cap 3. At this time, the bumper cap assembly 5C is fitted over the radially outer side of the body portion 17 by making the base plate portion 261 of the plate 4C abut against the locking portion 24 of the outer cylinder 14 of the shock absorber body 2 at the surface portion 266. In this state, the bumper cap assembly 5C is fixed to the outer cylinder 14 of the shock absorber body 2 by, for example, crimping a plurality of circumferential points of the cylinder portion 85 of the bumper cap 3 radially inward.

[0156] In the bumper cap assembly 5C thus attached to the shock absorber body 2, the bumper cap 3 and the plate 4C are provided at the axial end of the side from which the piston rod 31 of the cylinder 15 of the shock absorber body 2 protrudes. In addition, in the bumper cap assembly 5C, the bumper cap 3 has a bottom portion 86 having a hole portion 87 through which the piston rod 31 of the shock absorber body 2 can be inserted, and a tubular portion 85 covering the radial outer periphery of the cylinder 15 of the shock absorber body 2. In addition, in the bumper cap assembly 5C, the plate 4C has a hole portion 255 through which the piston rod 31 of the shock absorber body 2 can be inserted.

[0157] As described above, in the fourth embodiment, the plate 4C has the outer abutment portion 123C that abuts against the outer portion 111 of the bumper cap 3, the rib abutment portion 122C that abuts against the rib 92 of the bumper cap 3, and the locking portion 253, and is fixed to the bumper cap 3. Also, in the fourth embodiment, the plate 4C is formed so as to pass through the hole portion 87 of the bumper cap 3 and abut against the axial surface portions 96, 101, 102, and 107 of the bottom portion 86.

[0158] In the fourth embodiment, the bumper cap 3 has a rib 92 that protrudes in the axial direction from the outer side part 111 on the outer side of the bottom part 86 in the radial direction at the inner side part of the bottom part 86 in the radial direction. In the fourth embodiment, the bumper cap 3 is provided with a plate 4C having an outer abutment part 123C that abuts against the outer side part 111 of the bottom part 86 of the bumper cap 3 and a rib abutment part 122C that abuts against the rib 92 of the bottom part 86 of the bumper cap 3 and fixed to the bumper cap 3. As a result, in the fourth embodiment, the strength of the bottom part 86 of the bumper cap 3 can be improved, and further reinforced by the plate 4C. Therefore, in the fourth embodiment, it is possible to improve the load-bearing performance while suppressing an increase in weight and size.

[0159] In the fourth embodiment, the plate 4C is formed to pass through the hole 87 of the bumper cap 3 and abut against the axial surface portions 96, 101, 102, and 107 of the bottom portion 86. Therefore, the plate 4C can be fixed to the bumper cap 3 without welding. Therefore, the plate 4C can be stably fixed to the bumper cap 3.

[0160] In the fourth embodiment, the rib 92 may be formed in a single continuous annular shape over the entire circumference of the bumper cap 3, and the rib abutment portion 122C of the plate 4C may be formed in a single continuous annular shape over the entire circumference of the plate 4C.

[0161] [Fifth embodiment] Next, the fifth embodiment will be described with a focus on differences from the first embodiment, mainly with reference to Fig. 8. Note that parts common to the first embodiment will be designated by the same names and reference numerals.

[0162] In the fifth embodiment, a bumper cap assembly 5D shown in FIG. 8, which is partially different from the bumper cap assembly 5 of the first embodiment, is used instead of the bumper cap assembly 5.

[0163] The bumper cap assembly 5D has a bumper cap 3 similar to that of the bumper cap assembly 5, but has a plate 4D different from the plate 4 instead of the plate 4.

[0164] The plate 4D is an annular, one-piece metal product. The plate 4D has a disk-shaped portion 301, a cylindrical portion 302, and a locking portion 303.

[0165] The disk-shaped portion 301 is a disk having a hole. The tubular portion 302 is cylindrical and extends from an inner peripheral edge of the disk-shaped portion 301 to one side in the axial direction of the disk-shaped portion 301. The locking portion 303 extends outward in the radial direction of the tubular portion 302 from an edge of the tubular portion 302 on the opposite side to the disk-shaped portion 301 in the axial direction.

[0166] The plate 4D has a hole 305 penetrating the plate 4D in the axial direction on the radially inner side of the cylindrical portion 302. The outer diameter of the disk-shaped portion 301 of the plate 4D is equal to the outer diameter of the cylindrical portion 85 of the bumper cap 3. The inner diameter of the hole 305 is set to a size that does not interfere with the seal member 23.

[0167] The disk-shaped portion 301 has a flat plate-shaped base portion 311 and an outer contact portion 123D that protrudes from the outer side of the base portion 311 in the radial direction to the same side as the cylindrical portion 302 in the axial direction of the base portion 311.

[0168] The substrate portion 311 has a surface portion 315 on one side in the axial direction, and a surface portion 316 on the other side in the axial direction. The surfaces 315 and 316 are both flat surfaces extending perpendicular to the central axis of the substrate portion 311.

[0169] The outer abutment portion 123D is provided on the outer side in the radial direction of the plate 4D. The outer abutment portion 123D protrudes from the surface portion 316 of the base plate portion 311 to the opposite side to the surface portion 315. The outer abutment portion 123D is annular and continuous around the entire circumference of the disc-shaped portion 301. The outer abutment portion 123D has a surface portion 321 and a surface portion 322 on the opposite side to the surface portion 315 in the axial direction of the disc-shaped portion 301. The outer abutment portion 123D has the surface portion 321 on the outer side from the middle position in the radial direction of the disc-shaped portion 301, and the surface portion 322 on the inner side in the radial direction of the disc-shaped portion 301.

[0170] The surface portion 321 is flat and extends perpendicularly to the central axis of the disc-shaped portion 301. The surface portion 322 is inclined in the radial direction of the disc-shaped portion 301 so as to approach the surface portion 316 of the base plate portion 311 the further away from the surface portion 321, and merges with the surface portion 316. The surface portion 322 is tapered. The outer abutment portion 123D abuts against the surface portion 95 on the outer portion 111 of the bumper cap 3 at the surface portion 321, and abuts against the surfaces 104 of all the ribs 92 at the surface portion 322.

[0171] The rib abutment portion 122D is a portion of the base plate portion 311 that is radially inward of the outer abutment portion 123D. The rib abutment portion 122D is annular and continues around the entire circumference of the disc-shaped portion 301. The rib abutment portion 122D abuts on the surface portion 316 against the surface portions 101 of all of the ribs 92.

[0172] Before the plate 4D is attached to the bumper cap 3, the locking portion 303 is not formed, and the cylindrical portion 302 is accordingly long in the axial direction. With the plate 4D in this state, the cylindrical portion 302 is inserted into the hole 87 of the bumper cap 3 from the opposite side to the cylindrical portion 85 in the axial direction. Then, the surface 321 of the outer abutment portion 123D of the plate 4D abuts in surface contact with the surface 95 of the outer portion 111 of the bumper cap 3, the surface 322 of the outer abutment portion 123D abuts in surface contact with the surface 104 of all the ribs 92, and the surface 316 of the rib abutment portion 122D abuts in surface contact with the surface 101 of all the ribs 92.

[0173] From the above state, the portion of the cylindrical portion 302 protruding from the bumper cap 3 is crimped radially outward and plastically deformed to form the locking portion 303. At this time, the locking portion 303 abuts in a surface contact manner at a plurality of circumferential points on the locking portion 303 against the surfaces 102 of the ribs 92 that correspond one-to-one. As a result, the locking portion 303 is pressed against the surfaces 102 of all the ribs 92, and all the ribs 92 are sandwiched between the locking portion 303 and the rib abutment portion 122D. In this manner, the plate 4D and the bumper cap 3 are integrally joined to form the bumper cap assembly 5D.

[0174] The bumper cap assembly 5D having the above configuration is fitted over the radially outer side of the body portion 17 by inserting the main shaft portion 33 of the piston rod 31 of the shock absorber body 2 into the radially inner side of the hole portion 87 of the bumper cap 3 and the hole portion 305 of the plate 4D, and inserting the body portion 17 of the outer cylinder 14 of the shock absorber body 2 into the radially inner side of the tubular portion 85 of the bumper cap 3. At this time, the bottom portion 86 of the bumper cap 3 of the bumper cap assembly 5D is brought into contact with the locking portion 24 of the outer cylinder 14 of the shock absorber body 2 at the surface portion 96. In this state, the bumper cap assembly 5D is fixed to the outer cylinder 14 of the shock absorber body 2 by, for example, crimping a plurality of circumferential points of the tubular portion 85 of the bumper cap 3 radially inward.

[0175] In the bumper cap assembly 5D thus attached to the shock absorber body 2, the bumper cap 3 and the plate 4D are provided at the axial end of the side from which the piston rod 31 of the cylinder 15 of the shock absorber body 2 protrudes. In addition, in the bumper cap assembly 5D, the bumper cap 3 has a bottom portion 86 having a hole portion 87 through which the piston rod 31 of the shock absorber body 2 can be inserted, and a tubular portion 85 covering the radial outer periphery of the cylinder 15 of the shock absorber body 2. In addition, in the bumper cap assembly 5D, the plate 4D has a hole portion 305 through which the piston rod 31 of the shock absorber body 2 can be inserted.

[0176] As described above, in the fifth embodiment, the plate 4D has the outer abutment portion 123D that abuts against the outer portion 111 of the bumper cap 3, the rib abutment portion 122D that abuts against the rib 92 of the bumper cap 3, and the locking portion 303, and is fixed to the bumper cap 3. Also, in the fifth embodiment, the plate 4D is formed so as to pass through the hole portion 87 of the bumper cap 3 and abut against the axial surface portions 95, 101, 102, and 104 of the bottom portion 86.

[0177] In the fifth embodiment, the bumper cap 3 has a rib 92 that protrudes in the axial direction from the outer side part 111 on the outer side of the bottom part 86 in the radial direction at the inner side part of the bottom part 86 in the radial direction. In the fifth embodiment, the bumper cap 3 is provided with a plate 4D having an outer abutment part 123D that abuts against the outer side part 111 of the bottom part 86 of the bumper cap 3, a rib abutment part 122D that abuts against the rib 92 of the bottom part 86 of the bumper cap 3, and an engagement part 303, and fixed to the bumper cap 3. As a result, in the fifth embodiment, the strength of the bottom part 86 of the bumper cap 3 can be improved, and further reinforced by the plate 4D. Therefore, in the fifth embodiment, it is possible to improve the load-bearing performance while suppressing an increase in weight and size.

[0178] In the fifth embodiment, the plate 4D is formed to pass through the hole 87 of the bumper cap 3 and abut against the axial surface portions 95, 101, 102, and 104 of the bottom portion 86. Therefore, the plate 4D can be fixed to the bumper cap 3 without welding. Therefore, the plate 4D can be stably fixed to the bumper cap 3. [Explanation of symbols]

[0179] 1...shock absorber, 3...bumper cap, 4, 4A-4D...plate, 15...cylinder, 31...piston rod, 85...tubular portion, 86...bottom, 87...hole portion, 92...rib, 111...outer portion, 122, 122B-122D...rib abutment portion, 123, 123A-123D...outer abutment portion, 141, 141B, 142, 142A, 142B...welded portion, 171, 201...first plate, 172, 202...second plate.

Claims

1. A cylinder in which a working fluid is sealed; A piston rod protruding from an axial end of the cylinder; a bumper cap provided at an axial end of the cylinder, the bumper cap having a bottom portion having a hole through which the piston rod can be inserted and a cylindrical portion covering an outer periphery of the cylinder in a radial direction; A shock absorber comprising: the bumper cap has a rib at a radially inner portion of the bottom portion that protrudes in the axial direction beyond an outer portion of the bottom portion in the radial direction, a plate having an outer abutment portion that abuts against the outer portion and a rib abutment portion that abuts against the rib and is fixed to the bumper cap; buffer.

2. 2. The shock absorber according to claim 1, The rib is provided in plurality, The rib abutment portion is fixed to each of the plurality of ribs by a single welded portion, The outer abutment portion is fixed by a plurality of welds at positions in the circumferential direction of the bottom portion that are different from the welding positions of the rib abutment portion. buffer.

3. 2. The shock absorber according to claim 1, The plate is configured to pass through the hole and abut against the axial surface of the bottom. buffer.

4. 2. The shock absorber according to claim 1, The plate is A first plate abutting against the rib; a second plate abutting the outer portion; buffer.

5. 3. The shock absorber according to claim 2, The plurality of welds of the outer abutment portion are For one welded portion formed for each of the plurality of ribs, two welds are provided, and together with the one welded portion of the rib, a truss shape is formed. buffer.

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