Buffer and method for manufacturing a buffer
The shock absorber connects the mounting member and rod using an expandable ring member in annular grooves, addressing the limitations of caulking and crimping methods by ensuring a stable and equipment-efficient attachment.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- ASTEMO LTD
- Filing Date
- 2022-11-02
- Publication Date
- 2026-05-29
Smart Images
Figure 0007867419000001 
Figure 0007867419000002 
Figure 0007867419000003
Abstract
Description
Technical Field
[0001] The present invention relates to a shock absorber and a method for manufacturing the shock absorber.
Background Art
[0002] In shock absorbers, mechanical clinching, which is caulking, shrink fitting, etc. are employed as means for connecting the mounting member and the rod (see, for example, Patent Document 1).
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] It is desired to connect the mounting member and the rod by means other than caulking.
[0005] Therefore, an object of the present invention is to provide a shock absorber and a method for manufacturing the shock absorber that can connect the mounting member and the rod by means other than caulking.
Means for Solving the Problems
[0006] To achieve the above objective, one embodiment of the shock absorber according to the present invention comprises a cylinder in which a working fluid and a gas are sealed, a piston inserted into the cylinder, a rod with one end connected to the piston and the other end extending to the outside of the cylinder, and a mounting member attached to the other end of the rod, wherein the rod has an insertion portion that is inserted into and covered by the mounting member, and an outer annular groove provided on the outer circumference of the insertion portion, and the mounting member has a bottom portion, a cylindrical portion into which the insertion portion is inserted, and an inner annular groove provided on the inner circumference side of the cylindrical portion, and comprises a radially expandable and contractible ring member inserted into the inner annular groove and the outer annular groove.
[0007] One embodiment of the method for manufacturing a shock absorber according to the present invention comprises a cylinder in which a working fluid and a gas are sealed; a piston inserted into the cylinder; a rod whose first end is connected to the piston and whose second end extends to the outside of the cylinder, and which has an outer peripheral annular groove formed on the radially outer side of the second end; a mounting member attached to the second end of the rod, which has a bottom and a cylindrical portion, and which has an inner peripheral annular groove formed on the inner circumference side of the cylindrical portion; and a radially expandable and contractible ring member inserted into the inner peripheral annular groove and the outer peripheral annular groove, wherein the method for manufacturing a shock absorber comprises the steps of inserting the ring member into the inner peripheral annular groove and placing the mounting member into which the ring member is inserted over the rod. [Effects of the Invention]
[0008] According to the present invention, the mounting member and the rod can be joined by means other than crimping. [Brief explanation of the drawing]
[0009] [Figure 1] This is a partial cross-sectional front view showing a buffer according to one embodiment of the present invention. [Figure 2] This is a front view showing the main part of the buffer body of a buffer according to one embodiment of the present invention. [Figure 3]This is a partial cross-sectional front view showing a subassembly of a buffer according to one embodiment of the present invention. [Figure 4] This shows a ring member of a buffer according to one embodiment of the present invention, where (a) is a plan view and (b) is a front view. [Figure 5] This is a front view showing a cross-sectional portion of the main part of a buffer according to one embodiment of the present invention. [Modes for carrying out the invention]
[0010] Embodiments of the present invention will be described below with reference to the drawings.
[0011] The shock absorber 1 in the embodiment shown in Figure 1 is a shock absorber used in the suspension system of vehicles such as automobiles and railway vehicles. Specifically, shock absorber 1 is a shock absorber used in the suspension system of an automobile. Shock absorber 1 is placed between the vehicle body and the wheels to dampen the relative vibrations between them.
[0012] The shock absorber 1 comprises a shock absorber body 2, a rod-side mounting eye 3 (mounting member), a ring member 4, an elastic member 5, and a dust cover 6.
[0013] The shock absorber body 2 includes a cylinder 11, a piston 12, a rod 13, a free piston 14, a sealing member 15, and a cylinder-side mounting eye 16.
[0014] The cylinder 11 is a bottomed cylindrical shape having a cylindrical body 21 and a bottom 22 that closes one end of the body 21 in the axial direction.
[0015] The piston 12 is roughly disc-shaped and inserted into the cylinder 11. The piston 12 is fitted into the body 21 of the cylinder 11 so as to be slidable in the axial direction of the cylinder 11.
[0016] The rod 13 is made of metal and is rod-shaped. At the connecting part 25 of the first end, which is one end in the axial direction of the rod 13, it is arranged inside the cylinder 11 and connected to the piston 12, and the insertion part 26 of the second end, which is the other end in the axial direction, extends outside the cylinder 11. The rod 13 moves in the axial direction of the cylinder 11 integrally with the piston 12 while being arranged on the central axis of the cylinder 11.
[0017] The free piston 14 is substantially disc-shaped and is inserted between the piston 12 and the bottom 22 inside the cylinder 11. The free piston 14 is fitted to the body 21 of the cylinder 11 so as to be axially slidable within the cylinder 11.
[0018] The seal member 15 is provided on the side opposite to the bottom 22 in the axial direction of the cylinder 11. The seal member 15 closes the space between the body 21 of the cylinder 11 and the rod 13.
[0019] Inside the cylinder 11, oil as a working fluid is enclosed in the chamber on the side opposite to the free piston 14 of the piston 12 and in the chamber between the piston 12 and the free piston 14. Also, gas is enclosed in the chamber between the free piston 14 and the bottom 22 inside the cylinder 11. When the rod 13 enters the cylinder 11, the gas is compressed and deformed by the entering volume of the rod 13, and when the rod 13 exits the cylinder 11, the gas expands and deforms by the exiting volume of the rod.
[0020] Although not shown in the figure, the piston 12 is provided with a damping force generation mechanism that generates a damping force while flowing the oil in the chamber on the side opposite to the free piston 14 of the piston 12 into the chamber between the piston 12 and the free piston 14 in the extending stroke where the amount of extension of the rod 13 from the cylinder 11 increases. Also, although not shown in the figure, the piston 12 is provided with a damping force generation mechanism that generates a damping force while flowing the oil in the chamber between the piston 12 and the free piston 14 into the chamber on the side opposite to the free piston 14 of the piston 12 in the retracting stroke where the amount of extension of the rod 13 from the cylinder 11 decreases.
[0021] The cylinder-side mounting eye 16 is attached to the side opposite to the body portion 21 of the bottom portion 22 in the axial direction of the cylinder 11. The cylinder-side mounting eye 16 has an eye body 31 attached to the cylinder 11 and a rubber bush 32 attached to the eye body 31. The rubber bush 32 has a metal cylindrical connecting member 34 and a rubber annular rubber member 35 adhered to the outer peripheral side of the connecting member 34. The eye body 31 is made of metal and is formed in an annular shape. The rubber bush 32 is fitted inside the eye body 31 in the rubber member 35 and is attached to the eye body 31. The cylinder-side mounting eye 16 has the eye body 31 fixed to the bottom portion 22 by welding. At the time of this fixing, the eye body 31 is arranged such that the center in the direction of the central axis of the eye body 31 passes through the central axis of the cylinder 11, and the central axis of the eye body 31 is orthogonal to the central axis of the cover member 72.
[0022] The shock absorber body 2 has a cylinder 11, a piston 12, a rod 13, a free piston 14, a seal member 15, and a cylinder-side mounting eye 16, and these are pre-assembled to form the shock absorber body 2. In the shock absorber body 2, the insertion portion 26 of the rod 13 protrudes outward from the cylinder 11 and the seal member 15, and a rod-side mounting eye 3 is attached to this insertion portion 26 by a ring member 4.
[0023] The rod-side mounting eye 3 has a metal eye body 41 attached to the rod 13 and a rubber bush 42 attached to the eye body 41. The rubber bush 42 has a metal cylindrical connecting member 44 and a rubber annular rubber member 45 adhered to the outer peripheral side of the connecting member 44. The rubber bush 42 is attached to the eye body 41 by being fitted into the eye body 41 in the rubber member 45.
[0024] The dust cover 6 is made of synthetic resin and is cylindrical in shape. The dust cover 6 is attached to the eye body 41 of the rod-side mounting eye 3. When attached to the rod-side mounting eye 3, the dust cover 6 extends from the rod-side mounting eye 3 toward the cylinder 11, covering the portion of the rod 13 that extends from the cylinder 11, the portion of the cylinder 11 opposite the bottom 22, and the sealing member 15.
[0025] As described above, the rod-side mounting eye 3 is attached to the eye body 41 at the insertion portion 26 of the rod 13 of the shock absorber body 2. The insertion portion 26 of the rod 13 is a solid rod with a circular cross-section, and is fitted into the eye body 41 when installed.
[0026] As shown in Figure 2, the insertion portion 26 of the rod 13 has a radially outer peripheral surface portion 51, an end surface portion 52, and a tapered surface portion 53 connecting the end surface portion 52 and the peripheral surface portion 51. The end surface portion 52 is the end surface of the insertion portion 26 opposite to the connecting portion 25 shown in Figure 1.
[0027] The outer peripheral surface portion 51 shown in Figure 2 is cylindrical in shape.
[0028] The end face portion 52 is planar in shape, extending perpendicularly to the central axis of the outer peripheral surface portion 51.
[0029] The tapered surface portion 53 expands from the outer peripheral edge of the end surface portion 52, widening in diameter towards the connecting portion 25 shown in Figure 1 in the axial direction of the rod 13. The tapered surface portion 53 shown in Figure 2 is connected to the end edge of the outer peripheral surface portion 51 on the side opposite to the connecting portion 25 shown in Figure 1 in the axial direction of the rod 13. In other words, the tapered surface portion 53 shown in Figure 2 is tapered, with its diameter increasing as it moves away from the end surface portion 52 in the axial direction of the rod 13.
[0030] An outer annular groove 61 is provided on the outer circumference of the insertion portion 26. The outer annular groove 61 is formed at an intermediate position in the axial direction of the outer surface portion 51 and is recessed inward in the radial direction from the outer surface portion 51. The outer annular groove 61 is an annular shape centered on the central axis of the outer surface portion 51.
[0031] The outer annular groove 61 has a groove bottom surface portion 62, a groove wall surface portion 63, and a groove wall surface portion 64.
[0032] The groove bottom surface 62 is located on the radially innermost side of the outer annular groove 61. The groove bottom surface 62 has an outer diameter smaller than the outer diameter of the outer surface 51 and is a cylindrical surface coaxial with the outer surface 51.
[0033] The groove wall portion 63 is located on the outer annular groove 61, closest to the axial end face portion 52. The groove wall portion 63 is planar and extends parallel to the end face portion 52.
[0034] The groove wall portion 64 is located on the outer annular groove 61, furthest away from the axial end portion 52. The groove wall portion 64 is tapered, inclining further away from the groove wall portion 63 in the axial direction of the outer annular groove 61 as it moves radially outward. The groove wall portion 64 faces the groove wall portion 63 in the axial direction of the outer annular groove 61.
[0035] As shown in Figure 3, the eye body 41 includes an annular ring member 71, a cover member 72 fixed to the outer circumference of the ring member 71 along the radial direction of the ring member 71, and a flange member 73 interposed between the ring member 71 and the cover member 72. The eye body 41 is constructed by integrating the ring member 71, the cover member 72, and the flange member 73.
[0036] The annular member 71 is made of metal, and a rubber bushing 42 is fitted to its radially inward side. This attaches the rubber bushing 42 to the eye body 41.
[0037] The cover member 72 is made of metal and has a cylindrical portion 81, a bottom portion 82 that closes one side of the cylindrical portion 81 in the axial direction, and a mounting shaft portion 83 that protrudes from the bottom portion 82 on the side opposite to the cylindrical portion 81 in the axial direction. The cover member 72 has an opening 84 on the side of the cylindrical portion 81 opposite to the bottom portion 82 in the axial direction. The insertion portion 26 of the rod 13 shown in Figure 2 is inserted into the cylindrical portion 81 through this opening 84 of the cover member 72.
[0038] As shown in Figure 3, the cylindrical portion 81 of the cover member 72 has an inner circumferential surface portion 91 on the radially inner side, an end surface portion 92 on the side opposite to the bottom portion 82 in the axial direction of the cylindrical portion 81, and a tapered surface portion 93 connecting the end surface portion 92 and the inner circumferential surface portion 91.
[0039] The inner circumferential surface portion 91 is cylindrical in shape. The inner circumferential surface portion 91 has a diameter that is slightly larger than the diameter of the outer circumferential surface portion 51 of the insertion portion 26, as the insertion portion 26 of the rod 13 shown in Figure 2 is inserted into it.
[0040] The end face portion 92 shown in Figure 3 is planar in shape, extending perpendicularly to the central axis of the inner circumferential surface portion 91.
[0041] The tapered surface portion 93 extends from the inner peripheral edge of the end surface portion 92, gradually decreasing in diameter, towards the bottom portion 82 in the axial direction of the cylindrical portion 81, and connects to the end edge of the inner peripheral surface portion 91 opposite to the bottom portion 82 in the axial direction. In other words, the tapered surface portion 93 is tapered, with its diameter decreasing as it moves away from the end surface portion 92 in the axial direction of the cylindrical portion 81.
[0042] An inner circumferential annular groove 101 is provided on the inner circumference of the cylindrical portion 81. The inner circumferential annular groove 101 is formed at an intermediate position in the axial direction of the inner circumferential surface portion 91 and is recessed outward in the radial direction from the inner circumferential surface portion 91. The inner circumferential annular groove 101 is an annular shape centered on the central axis of the inner circumferential surface portion 91.
[0043] The inner circumferential annular groove 101 has a groove bottom surface portion 102, a groove wall surface portion 103, and a groove wall surface portion 104.
[0044] The groove bottom surface 102 is located on the radially outermost side of the inner circumferential annular groove 101. The groove bottom surface 102 has a larger diameter than the inner circumferential surface 91 and is a cylindrical surface coaxial with the inner circumferential surface 91.
[0045] The groove wall portion 103 is located on the axial bottom side 82 in the inner circumferential annular groove 101. The groove wall portion 103 is planar and extends parallel to the end face portion 92.
[0046] The groove wall surface 104 is located on the inner circumferential annular groove 101, furthest from the axial bottom 82. The groove wall surface 104 is planar and extends parallel to the end surface 92. The groove wall surface 104 faces the groove wall surface 103 in the axial direction of the inner circumferential annular groove 101.
[0047] The bottom portion 82 of the cover member 72 has a bottom surface portion 111 on the side of the cylindrical portion 81 in the axial direction of the cover member 72. The bottom surface portion 111 is connected to the entire circumference of the edge of the inner circumferential surface portion 91 opposite to the end surface portion 92 in the axial direction, and extends radially inward from the inner circumferential surface portion 91. The bottom surface portion 111 is planar in shape and extends perpendicularly to the central axis of the inner circumferential surface portion 91. The outer diameter of the outer circumference of the bottom portion 82 is the same as the outer diameter of the cylindrical portion 81 in the axial direction of the portion on the side of the cylindrical portion 81, and the outer diameter of the portion on the opposite side of the cylindrical portion 81 in the axial direction becomes smaller as it moves away from the cylindrical portion 81 in the axial direction.
[0048] The mounting shaft portion 83 of the cover member 72 is cylindrical and coaxial with the cylindrical portion 81, and protrudes from the bottom portion 82 on the opposite side from the cylindrical portion 81 in the axial direction of the cover member 72.
[0049] As described above, the cover member 72 has a bottom portion 82, a cylindrical portion 81, and an inner annular groove 101 provided on the inner circumference side of the cylindrical portion 81.
[0050] The flange member 73 is made of metal and is a perforated, stepped disc shape.
[0051] The eye body 41 is fixed to the outer circumference of the annular member 71 by welding, with the mounting shaft portion 83 of the cover member 72 inserted radially inward into the flange member 73. At the same time, the flange member 73 is also welded to the mounting shaft portion 83 and the annular member 71. The annular member 71, cover member 72, and flange member 73 are integrated by welding to form the eye body 41. In this integrated state, the center of the annular member 71 in the direction of its central axis passes through the central axis of the cover member 72, and the central axis of the annular member 71 is perpendicular to the central axis of the cover member 72. In this integrated state, the flange member 73 is arranged coaxially with the cover member 72 and extends outward from the cover member 72 in the radial direction of the cover member 72.
[0052] As shown in Figure 4(a), the ring member 4 is a C-shaped ring in which a portion of the ring is cut, and a gap extending in the circumferential direction of the ring member 4 is provided in the cut portion. The ring member 4 is expandable and contractible in the radial direction by elastic deformation.
[0053] If we consider one side of the ring member 4 as the axial first side and the other side as the axial second side, then as shown in Figure 4(b), the ring member 4 has peaks 121 and valleys 122 that are recessed toward the axial second side relative to the peaks 121. Multiple peaks 121 on the axial first side of the ring member 4 are provided at equal intervals in the circumferential direction of the ring member 4. Multiple valleys 122 on the axial first side of the ring member 4 are provided between adjacent peaks 121 on the axial first side of the ring member 4 in the circumferential direction of the ring member 4. As a result, multiple valleys 122 on the axial first side of the ring member 4 are also provided at equal intervals in the circumferential direction of the ring member 4. On the axial first side of the ring member 4, the peaks 121 and valleys 122 are arranged alternately in the circumferential direction of the ring member 4. In the axial direction (thickness direction) of the ring member 4, all peaks 121 on the first axial side have the same height at their peaks, and all valleys 122 on the first axial side have the same height at their valley bottoms.
[0054] The ring member 4 also has peaks 121 and valleys 122 that are recessed toward the first axial direction from the peaks 121 on the second axial side. The peaks 121 on the second axial side are provided on the back side of the valleys 122 on the first axial side, and vice versa. Multiple peaks 121 on the second axial side of the ring member 4 are provided at equal intervals in the circumferential direction of the ring member 4. Multiple valleys 122 on the second axial side of the ring member 4 are provided between adjacent peaks 121 on the second axial side of the ring member 4 in the circumferential direction of the ring member 4. As a result, multiple valleys 122 on the second axial side of the ring member 4 are also provided at equal intervals in the circumferential direction of the ring member 4. On the second axial side of the ring member 4, the peaks 121 and valleys 122 are arranged alternately in the circumferential direction of the ring member 4. In the axial direction (thickness direction) of the ring member 4, all the peaks 121 on the second axial side have the same height at their peaks, and all the valleys 122 on the second axial side have the same height at their valley bottoms.
[0055] The ring member 4 is a press-formed product, punched out in a roughly C-shape from a flat plate-shaped member, and then plastically deformed in the axial direction, i.e., in the thickness direction, to form the shape described above. The ring member 4 is formed in a wave shape having peaks 121 and valleys 122 in its axial direction. The ring member 4 is compressible in the axial direction by elastic deformation.
[0056] As shown in Figure 4(a), the ring member 4 has an inner circumferential surface portion 125 on the radially inner side and an outer circumferential surface portion 126 on the radially outer side.
[0057] The inner circumferential surface portion 125 is cylindrical in shape. The outer circumferential surface portion 126 has a larger diameter than the inner circumferential surface portion 125 and is a cylindrical surface coaxial with the inner circumferential surface portion 125.
[0058] The axial thickness of the ring member 4 in its natural state without any external force applied, that is, the maximum distance between the first axially facing peak 121 and the second axially facing peak 121 which are opposite to each other in the axial direction of the ring member 4, is slightly shorter than the groove width of the inner annular groove 101 of the rod-side mounting eye 3 shown in Figure 3, that is, the distance between the groove wall surface portion 103 and the groove wall surface portion 104.
[0059] The ring member 4 shown in Figure 4 has an outer diameter in its natural state, i.e., the diameter of the outer peripheral surface portion 126, which is smaller than the groove bottom diameter of the inner annular groove 101 of the rod-side mounting eye 3 shown in Figure 3, i.e., the diameter of the groove bottom surface portion 102, and larger than the inner diameter of the cylindrical portion 81 of the rod-side mounting eye 3, i.e., the diameter of the inner peripheral surface portion 91.
[0060] In the ring member 4 shown in Figure 4, the radial width in its natural state, i.e., the difference in radius between the outer circumferential surface portion 126 and the inner circumferential surface portion 125, is smaller than the groove depth of the inner annular groove 101 of the cylindrical portion 81 of the rod-side mounting eye 3 shown in Figure 3, i.e., the difference in radius between the inner circumferential surface portion 91 and the groove bottom surface portion 102.
[0061] The ring member 4 shown in Figure 4 has an axial thickness in its natural state that is slightly shorter than the groove width of the outer annular groove 61 of the insertion portion 26 of the rod 13 shown in Figure 2, that is, the distance between the groove wall surface portion 63 and the groove wall surface portion 64.
[0062] The ring member 4 shown in Figure 4 has an inner diameter in its natural state, i.e., the diameter of the inner circumferential surface portion 125, which is smaller than the outer diameter of the outermost dimension of the insertion portion 26 of the rod 13, i.e., the diameter of the outer circumferential surface portion 51, and larger than the outer diameter of the end face portion 52 of the insertion portion 26 of the rod 13. In other words, the inner diameter of the ring member 4 shown in Figure 4 in its natural state is larger than the outer diameter of the end face portion 52 of the rod 13 shown in Figure 3, and smaller than the outermost dimension of the insertion portion 26. The inner diameter of the ring member 4 in its natural state, i.e., the diameter of the inner circumferential surface portion 125, is slightly smaller than the groove bottom diameter of the outer annular groove 61 of the rod 13 shown in Figure 3, i.e., the diameter of the groove bottom surface portion 62.
[0063] The elastic member 5 shown in Figure 3 is made of an elastic material such as rubber and is a circular, flat plate. In its natural state, when no external force is applied, the outer diameter of the elastic member 5 is slightly larger than the inner diameter of the cylindrical portion 81 of the rod-side mounting eye 3, i.e., the diameter of the inner circumferential surface portion 91. In other words, the outer diameter of the elastic member 5 is formed to be larger than the inner diameter of the cylindrical portion 81. In its natural state, when no external force is applied, the axial length, i.e., thickness of the elastic member 5 is shorter than the length between the groove wall portion 103 of the inner circumferential annular groove 101 and the bottom surface portion 111 of the bottom portion 82.
[0064] In the manufacturing method of the shock absorber 1, the rod-side mounting eye 3 is attached to the insertion portion 26 of the rod 13 of the shock absorber body 2, which is pre-assembled with the cylinder 11, piston 12, rod 13, free piston 14, sealing member 15, and cylinder-side mounting eye 16 shown in Figure 1, by a ring member 4.
[0065] When attaching the rod-side mounting eye 3 to the rod 13, as shown in Figure 3, an elastic member fitting process is performed in which the elastic member 5 is fitted inside the cylindrical portion 81 of the rod-side mounting eye 3. In this elastic member fitting process, the elastic member 5 is inserted into the cylindrical portion 81 from the opening 84 side and pushed in with a cylindrical jig, for example, until it reaches the bottom portion 82 side and makes surface contact with the bottom surface portion 111. As a result, the elastic member 5 elastically deforms radially and adheres tightly to the inner circumferential surface portion 91 of the cylindrical portion 81, and is held in place by the frictional force. After the elastic member fitting process, the entire elastic member 5 is located on the bottom 82 side of the inner circumferential annular groove 101 in the axial direction of the cylindrical portion 81.
[0066] After the elastic member fitting process, a ring member fitting process is performed in which the ring member 4 is fitted to the opening 84 side of the inner circumferential surface portion 91 of the cylindrical portion 81 while reducing its diameter radially inward. In this ring member fitting process, for example, the ring member 4 is inserted from the large diameter side into the inner circumferential surface of a jig having a tapered inner circumferential surface, and the ring member 4 is reduced in diameter by pushing it to the small diameter side of the inner circumferential surface. Then, with the jig in contact with the end face portion 92 of the cylindrical portion 81, the ring member 4 is pushed into the cylindrical portion 81.
[0067] After the ring member fitting process, a ring member mounting process is performed in which the ring member 4 is moved along the axial direction of the cylindrical portion 81 toward the bottom surface portion 111 using a cylindrical jig, while maintaining the ring member 4 in a state parallel to the bottom surface portion 111. As a result, the ring member 4 expands in diameter due to its own elastic force at the position of the inner annular groove 101 of the cylindrical portion 81 and is inserted into the inner annular groove 101. Both the ring member fitting process and the ring member mounting process are processes for inserting the ring member 4 into the inner annular groove 101.
[0068] By performing the elastic member fitting process, ring member fitting process, and ring member mounting process described above, the sub-assembly 141 is obtained in the state shown in Figure 3, with the elastic member 5 and ring member 4 pre-assembled on the rod-side mounting eye 3.
[0069] Next, a sub-assembly mounting process is performed in which the sub-assembly 141 is attached so as to fit over the insertion portion 26 of the rod 13 shown in Figure 2. The sub-assembly mounting process is the process of placing the rod-side mounting eye 3, into which the ring member 4 is inserted, over the rod 13. In the sub-assembly mounting process, the sub-assembly 141 is placed over the insertion portion 26 so as to cover it, with the inner circumferential surface portion 91 of the cylindrical portion 81 being guided by the tapered surface portion 53 of the rod 13. In other words, the insertion portion 26 of the rod 13 is inserted into the cylindrical portion 81 of the sub-assembly 141 from the opening 84 side. To put it another way, the insertion portion 26 of the rod 13 is inserted into and covered by the rod-side mounting eye 3. To put it another way, the insertion portion 26 is inserted into the cylindrical portion 81 of the rod-side mounting eye 3.
[0070] As described above, since the inner diameter of the ring member 4 is larger than the outer diameter of the end face portion 52 of the insertion portion 26, i.e., the minimum inner diameter of the tapered surface portion 53, the insertion portion 26 moves radially inward of the ring member 4 at the tapered surface portion 53 during insertion into the cylindrical portion 81, thereby expanding the diameter of the ring member 4 radially outward. At this time, the ring member 4 comes into contact with the groove wall portion 103 of the inner annular groove 101, restricting its axial movement relative to the rod-side mounting eye 3. The insertion portion 26 then expands the diameter of the ring member 4 within the inner annular groove 101 until the inner surface portion 125 rides over the outer surface portion 51 of the insertion portion 26.
[0071] In this way, with the ring member 4 riding on the outer peripheral surface 51 of the insertion portion 26, the sub-assembly 141 further increases the insertion amount of the insertion portion 26. Then, in the axial direction of the rod 13, when the ring member 4 of the sub-assembly 141 moves to the position of the outer peripheral annular groove 61 of the insertion portion 26, the ring member 4 shrinks in diameter and is inserted into the outer peripheral annular groove 61, and as shown in Figure 5, the inner peripheral surface 125 presses against the groove bottom surface 62. In this state, the inner diameter of the ring member 4, i.e. the diameter of the inner peripheral surface 125, becomes smaller than the outer diameter of the insertion portion 26, i.e. the diameter of the outer peripheral surface 51, and the outer diameter, i.e. the diameter of the outer peripheral surface 126, becomes larger than the inner diameter of the cylindrical portion 81, i.e. the diameter of the inner peripheral surface 91. Thus, the ring member 4 is simultaneously inserted into the inner peripheral annular groove 101 and the outer peripheral annular groove 61.
[0072] Here, in the radial direction of the ring member 4, the gap formed between the ring member 4, which is fitted into the inner annular groove 101 and the outer annular groove 61, and the inner annular groove 101 is formed to be larger than the groove depth of the outer annular groove 61. That is, when the ring member 4 is fitted into the inner annular groove 101 and the outer annular groove 61, the difference in radius between the groove bottom surface 102 of the inner annular groove 101 and the outer circumferential surface 126 of the ring member 4 is larger than the difference in radius between the outer circumferential surface 51 of the insertion portion 26 and the groove bottom surface 62 of the outer annular groove 61.
[0073] As described above, when the insertion portion 26 is inserted into the rod-side mounting eye 3 until the ring member 4 enters the outer annular groove 61, the insertion portion 26 abuts against the elastic member 5 at its end face portion 52, compressing and deforming the elastic member 5 by being sandwiched between the bottom portion 111 of the bottom portion 82. In other words, the elastic member 5 is sandwiched between the rod 13 and the bottom portion 82 of the rod-side mounting eye 3 in the axial direction. Then, due to the elastic force of this elastic member 5, the groove wall portion 63 of the outer annular groove 61 presses against the top portions of the multiple peaks 121 on the first axial side of the ring member 4, and also presses against the groove wall portion 104 of the inner annular groove 101 the top portions of the multiple peaks 121 on the second axial side of the ring member 4. When attached to the rod 13, the ring member 4 is formed in a wave shape having peaks 121 and valleys 122 in the axial direction of the rod 13.
[0074] In this way, the rod-side mounting eye 3, which has a cylindrical portion 81 with an inner annular groove 101 formed on its inner circumference and a bottom portion 82, is attached to the insertion portion 26 of the rod 13 by a radially expandable and contractible ring member 4 that is inserted into the outer annular groove 61 and the inner annular groove 101. In this state, the eye body 41 has its center in the direction of the central axis of the annular member 71 passing through the central axes of the rod 13 and the cylinder 11, and the central axis of the annular member 71 is perpendicular to the central axes of the rod 13 and the cylinder 11.
[0075] In the sub-assembly mounting process, the sub-assembly 141, which includes the rod-side mounting eye 3 into which the ring member 4 is inserted, is attached to the rod 13 of the shock absorber body 2 while pressing the rod 13 in the contraction direction. Therefore, the sub-assembly mounting process, in which the sub-assembly 141 is placed over the rod 13, can include a measurement process for measuring the extrusion force that pushes the rod 13 outward in the axial direction of the cylinder 11 due to the pressure inside the cylinder 11. That is, for example, the sub-assembly 141 is held by the sensor part of the measuring device that measures this extrusion force, the rod 13 is pushed into the cylinder 11 with the sub-assembly 141 and the extrusion force is measured while the sub-assembly 141 is attached to the rod 13, and then the holding of the sub-assembly 141 by the measuring device is released.
[0076] After attaching the sub-assembly 141 to the rod 13, the dust cover 6 is fitted onto the outer circumference of the flange member 73 of the rod-side mounting eye 3. Alternatively, the sub-assembly 141 may include the dust cover 6, and this sub-assembly 141 including the dust cover 6 may be assembled to the shock absorber body 2 in the same manner as described above.
[0077] The shock absorber 1 is manufactured in the manner described above. Therefore, the elastic member fitting step, ring member fitting step, ring member mounting step, and sub-assembly mounting step described above are included in the manufacturing method of the shock absorber 1.
[0078] As described above, the shock absorber 1 has the insertion portion 26 of the rod 13 inserted into and covered by the rod-side mounting eye 3. In other words, the shock absorber 1 has the insertion portion 26 inserted into the cylindrical portion 81 of the rod-side mounting eye 3.
[0079] In the above manufacturing method, the example given was that in the sub-assembly mounting process, the ring member 4 is pre-attached to the rod-side mounting eye 3, and the rod-side mounting eye 3 is placed over the insertion portion 26 of the rod 13. However, the ring member 4 may be pre-attached to the outer annular groove 61 of the insertion portion 26, and the rod-side mounting eye 3 may be placed over the insertion portion 26. In this case, the groove depth of the outer annular groove 61 of the rod 13, i.e., the difference in radius between the outer annular groove 51 and the groove bottom surface 62, as shown in Figure 2, is made larger than the radial width of the ring member 4 in its natural state, i.e., the difference in radius between the outer annular groove 126 and the inner annular groove 125. Also, the outer diameter of the ring member 4 in its natural state, i.e., the diameter of the outer annular groove 126, is made slightly larger than the groove bottom diameter of the inner annular groove 101, i.e., the diameter of the groove bottom surface 102. When the rod-side mounting eye 3 is placed over the insertion portion 26, the ring member 4, which is pre-attached to the insertion portion 26, shrinks in diameter within the outer annular groove 61 until its outer surface portion 126 rides up onto the inner surface portion 91 of the cylindrical portion 81. Then, it expands in diameter at the position of the inner annular groove 101, entering the inner annular groove 101 and pressing its outer surface portion 126 against the groove bottom portion 102. In this state, the inner diameter of the ring member 4, i.e., the diameter of the inner surface portion 125, becomes smaller than the outer diameter of the insertion portion 26, i.e., the outer diameter of the outer surface portion 51, and the outer diameter, i.e., the diameter of the outer surface portion 126, becomes larger than the inner diameter of the cylindrical portion 81, i.e., the diameter of the inner surface portion 91. Thus, the ring member 4 is simultaneously inserted into the inner annular groove 101 and the outer annular groove 61.
[0080] In this case as well, when the insertion portion 26 is inserted into the rod-side mounting eye 3 until the ring member 4 is in the inner annular groove 101, the elastic force of the elastic member 5 causes the groove wall portion 63 of the outer annular groove 61 to press against the ring member 4, and also causes the ring member 4 to press against the groove wall portion 104 of the inner annular groove 101.
[0081] The shock absorber 1 is supported by the vehicle body on one side of either the rod-side mounting eye 3 or the cylinder-side mounting eye 16, and the other side is connected to the wheel. Specifically, the shock absorber 1 has the connecting member 44 of the rod-side mounting eye 3 attached to the rod 13 connected to the vehicle body, and the connecting member 34 of the cylinder-side mounting eye 16 attached to the cylinder 11 connected to the wheel. Alternatively, the shock absorber 1 may be configured in the opposite way, with the connecting member 34 of the cylinder-side mounting eye 16 attached to the cylinder 11 connected to the vehicle body, and the connecting member 44 of the rod-side mounting eye 3 attached to the rod 13 connected to the wheel.
[0082] During the extension stroke, the shock absorber 1's rod-side mounting eye 3 pulls the rod 13 out of the cylinder 11. Initially, the rod-side mounting eye 3 presses the ring member 4 against the groove wall 63 of the outer annular groove 61 with the groove wall 104 of the inner annular groove 101, compressing and deforming the ring member 4 in the axial direction (thickness direction). Subsequently, when the ring member 4 can no longer be deformed in the axial direction, the rod-side mounting eye 3, the ring member 4, and the rod 13 move together in the extension direction with their relative axial movement restricted.
[0083] During the compression stroke, the shock absorber 1's rod-side mounting eye 3 pushes the rod 13 into the cylinder 11. Initially, the rod-side mounting eye 3 presses the elastic member 5 against the end face 52 of the rod 13 with the bottom surface 111 of the bottom 82, compressing and deforming the elastic member 5 in the axial direction (thickness direction). Subsequently, when the elastic member 5 can no longer be deformed in the axial direction, the rod-side mounting eye 3, the elastic member 5, and the rod 13 move together in the compression direction with their relative axial movement restricted.
[0084] Patent Document 1, mentioned above, discloses the use of shrinking, a method of joining a mounting member and a rod by crimping, as a means of joining them in a shock absorber. When using methods of joining the mounting member and the rod by crimping, such as mechanical clinching or shrinking, crimping of the rod can cause losses in the sliding part of the shock absorber, variations in the joining strength can occur due to manufacturing variations in crimping, and capital investment may increase due to the introduction of dedicated equipment for crimping. For this reason, it is desirable to join the mounting member and the rod by means other than crimping.
[0085] The shock absorber 1 of this embodiment has a rod 13 which has an insertion portion 26 into which the rod-side mounting eye 3 is inserted and covered, and an outer peripheral annular groove 61 provided on the outer circumference of the insertion portion 26. The rod-side mounting eye 3 has a bottom portion 82, a cylindrical portion 81 into which the insertion portion 26 is inserted, and an inner peripheral annular groove 101 provided on the inner circumference of the cylindrical portion 81. The shock absorber 1 is equipped with a radially expandable and contractible ring member 4 which is inserted into the inner peripheral annular groove 101 and the outer peripheral annular groove 61. Therefore, the rod-side mounting eye 3 can be connected to the rod 13 by the ring member 4 inserted into the outer peripheral annular groove 61 of the rod 13 and the inner peripheral annular groove 101 of the rod-side mounting eye 3. Thus, the rod-side mounting eye 3 and the rod 13 can be connected by means other than crimping. As a result, it is possible to suppress the loss of the sliding part of the shock absorber 1, variations in connection strength, and increased capital investment that were necessary in the case of crimping. Therefore, it is possible to increase the axial length of the sliding part of the shock absorber 1, stabilize the joint strength, and reduce manufacturing costs.
[0086] Furthermore, the shock absorber 1 is provided with an elastic member 5 that is sandwiched between the rod 13 and the bottom 82 of the rod-side mounting eye 3. Therefore, the elastic member 5 can suppress axial rattle of the rod-side mounting eye 3 relative to the rod 13 and the resulting generation of abnormal noise.
[0087] Furthermore, the shock absorber 1 is formed such that the outer diameter of the elastic member 5 is larger than the inner diameter of the cylindrical portion 81. This makes it possible to pre-assemble the elastic member 5 to the rod-side mounting eye 3. Thus, the elastic member 5 can be assembled to the rod 13 together with the rod-side mounting eye 3, making the assembly of the elastic member 5 easier compared to the case where the rod-side mounting eye 3 is placed over the rod 13 with the elastic member 5 already mounted.
[0088] Furthermore, the shock absorber 1 has a ring member 4 that is formed in a wave shape with peaks 121 and valleys 122 in the axial direction of the rod 13. Therefore, the ring member 4 can suppress axial rattle of the rod-side mounting eye 3 relative to the rod 13 and the resulting generation of abnormal noise.
[0089] Furthermore, the shock absorber 1 is formed such that the inner diameter of the ring member 4 is larger than the outer diameter of the end face portion 52 and smaller than the outermost diameter of the insertion portion 26. Since the inner diameter of the ring member 4 is larger than the outer diameter of the end face portion 52 of the rod 13, it is easy to attach the ring member 4 to the rod 13.
[0090] Furthermore, the buffer 1 is designed such that, in the radial direction of the ring member 4, the gap formed between the ring member 4, which is fitted into the inner annular groove 101 and the outer annular groove 61, and the inner annular groove 101 is larger than the groove depth of the outer annular groove 61. This ensures that the ring member 4, which is pre-attached to the inner annular groove 101 of the rod-side mounting eye 3, can be securely mounted to the outer annular groove 61 of the rod 13 in a state where its diameter has been expanded.
[0091] The manufacturing method for the shock absorber 1 includes a ring member fitting step and a ring member mounting step, in which the ring member 4 is inserted into the inner annular groove 101 of the rod-side mounting eye 3, and a step of placing the rod-side mounting eye 3, in which the ring member 4 is inserted into the inner annular groove 101, over the rod 13. Therefore, in addition to improving the quality of the shock absorber 1 and reducing manufacturing costs as described above, it is possible to easily connect the rod-side mounting eye 3 to the rod 13 with the ring member 4.
[0092] Furthermore, the manufacturing method of the shock absorber 1 includes a step of measuring the force that pushes the rod 13 axially outward from the cylinder 11 due to the pressure inside the cylinder 11, in which the rod-side mounting eye 3, in which the ring member 4 is inserted into the inner circumferential annular groove 101, is fitted onto the rod 13. Therefore, compared to a case where this measurement step is performed separately from the step of fitting the rod-side mounting eye 3 onto the rod 13, the number of steps can be reduced and the manufacturing man-hours can be reduced. [Explanation of symbols]
[0093] 1... Shock absorber, 3... Rod-side mounting eye (mounting member), 4... Ring member, 5... Elastic member, 11... Cylinder, 12... Piston, 13... Rod, 26... Insertion part, 61... Outer circumference annular groove, 81... Cylindrical part, 82... Bottom part, 101... Inner circumference annular groove, 121... Peak part, 122... Valley part.
Claims
1. A cylinder containing a working fluid and a gas, The piston inserted into the cylinder, A rod having one end connected to the piston and the other end extending to the outside of the cylinder, A mounting member attached to the other end of the aforementioned rod, A shock absorber equipped with, The rod has an insertion portion that is inserted into and covered by the mounting member, and an outer annular groove provided on the outer circumference of the insertion portion. The mounting member has a bottom portion, a cylindrical portion into which the insertion portion is inserted, and an inner annular groove provided on the inner circumference side of the cylindrical portion. A radially expandable and contractible ring member inserted into the inner annular groove and the outer annular groove, The system comprises an elastic member sandwiched between the rod and the bottom of the mounting member, The insertion portion has a cylindrical outer surface portion that is radially outward, and a planar end surface portion that extends perpendicularly to the central axis of the outer surface portion. The aforementioned outer annular groove is In the outer annular groove, the innermost radially, the cylindrical groove bottom portion is coaxial with the outer surface portion, In the outer annular groove, the first groove wall portion is a flat, planar portion located on the end face side in the axial direction and extending parallel to the end face, The outer annular groove has a tapered second groove wall portion located on the side furthest from the axial end face portion, which is inclined so as to move radially outward, away from the first groove wall portion in the axial direction, The ring member is a press-formed product, which is punched out in a roughly C-shape from a flat plate-shaped member, and then plastically deformed in the axial direction to form a wave-shaped buffer having peaks and valleys in the axial direction.
2. A buffer according to claim 1, The buffer is formed such that the outer diameter of the elastic member is larger than the inner diameter of the cylindrical portion.
3. A buffer according to claim 1 or 2, A buffer in which, in the radial direction of the ring member, the gap formed between the ring member, which is fitted into the inner annular groove and the outer annular groove, and the inner annular groove is formed to be greater than the groove depth of the outer annular groove.
4. A buffer according to claim 1 or 2, The inner diameter of the ring member is larger than the outer diameter of the end face of the rod, and smaller than the outermost diameter of the insertion portion, forming a buffer.
5. A manufacturing method for manufacturing the buffer described in Claim 1, The steps include inserting the ring member into the inner annular groove, A step of placing the mounting member into which the ring member is inserted onto the rod, A method for manufacturing a buffer containing a buffer.
6. A method for manufacturing a buffer according to claim 5, A method for manufacturing a shock absorber, comprising the step of placing the mounting member into which the ring member is inserted over the rod, and including a measurement step of measuring the force that pushes the rod outward in the axial direction of the cylinder due to the pressure inside the cylinder.