Shock absorber

Abstract

Provided is a buffer capable of improving reliability. A shock absorber (10) is provided with a guide member (62) disposed within a cylinder (11), a first seal member (63) provided at an axial end of the guide member (62), a second seal member (64) provided at an axial end of the first seal member (63) on the opposite side from the guide member (62), and a lid member (65) provided at an axial end of the cylinder (11). The axial end portion is a fixed portion (53) which bends inward in the radial direction and suppresses axial movement of the second seal member (64). The cover member (65) is provided with: a bottom section (131); a tube section (132) that comes into contact with the outside in the radial direction of the cylinder (11); a contact section (133) that protrudes from the bottom section (131) and comes into contact with the second seal member (64); and a groove section (134) that is formed between the tube section (132) and the contact section (133) so as to be separated from the end section of the fixed section (53).

Description

Technical Field

[0001] This invention relates to buffers. Background Technology

[0002] In the buffer, a sealing component is provided between the cylinder body and the piston rod protruding from the cylinder body (for example, see Patent Documents 1-5).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Description of Chinese Patent Application Publication No. 105276067

[0006] Patent Document 2: Japanese Patent Application Publication No. 2012-202481

[0007] Patent Document 3: Chinese Utility Model Application Announcement No. 201437834 Specification

[0008] Patent Document 4: Japanese Patent Application Publication No. 2020-112260

[0009] Patent Document 5: Japanese Patent Application Publication No. 2013-72455 Summary of the Invention

[0010] The technical problem that the invention aims to solve

[0011] Here, in the buffer, the goal is to improve reliability.

[0012] Therefore, the object of the present invention is to provide a buffer that can improve reliability.

[0013] Technical solutions for solving technical problems

[0014] To achieve the above objectives, one embodiment of the buffer of the present invention comprises: a cylinder; a piston slidably disposed within the cylinder and dividing the cylinder into two chambers; a piston rod having a first end connected to the piston and a second end protruding from the cylinder; a guide member disposed within the cylinder and having a through hole for insertion of the piston rod; a first sealing member abutting against the guide member and disposed at an axial end of the guide member; a second sealing member abutting against the first sealing member and disposed at an axial end of the first sealing member opposite to the guide member; and a cover member disposed at an axial end of the cylinder; the axial end of the cylinder serves as a fixing portion that bends radially inward and inhibits axial movement of the second sealing member, the cover member comprising: a bottom having a through hole for insertion of the piston rod; a cylindrical portion abutting against the radially outer side of the cylinder; an abutting portion protruding from the bottom and abutting against the second sealing member; and a groove formed between the cylindrical portion and the abutting portion in a manner separate from the end of the fixing portion.

[0015] Invention Effects

[0016] According to the present invention, reliability can be improved. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of a buffer according to an embodiment of the present invention.

[0018] Figure 2 This is a cross-sectional view showing the main part of the buffer according to an embodiment of the present invention.

[0019] Explanation of reference numerals in the attached figures

[0020] 10…buffer, 11…cylinder, 53…fixed part, 62…guide part, 63…first sealing part, 64…second sealing part, 65…cover part, 88…through hole, 112…second elastic part (elastic part), 131…cover bottom (bottom), 132…cover cylinder part (cylinder part), 133…abutment part, 134…groove part, 135…connecting passage, 141…through hole, 180…piston, 181…first chamber, 182…second chamber, 190…piston rod. Detailed Implementation

[0021] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0022] Figure 1 This is a diagram illustrating the buffer 10 of this embodiment. The buffer 10 is a multi-cylinder hydraulic buffer. The buffer 10 is used in vehicles, specifically in the suspension system of automobiles.

[0023] The buffer 10 has a cylinder 11. The cylinder 11 has an inner tube 21, a separation tube 22, a shell 23, a first sealing ring 24, and a second sealing ring 25. The inner tube 21 and the separation tube 22 are both cylindrical. The shell 23 is a bottomed cylindrical shape. The first sealing ring 24 and the second sealing ring 25 are both annular.

[0024] The inner tube 21 is a metal product. The inner tube 21 is a cylindrical body, coaxially arranged with the outer shell 23 and located radially inside the outer shell 23. The outer shell 23 is located at the radially outermost position in the cylinder body 11.

[0025] The separator tube 22 is a metal product. The axial length of the separator tube 22 is shorter than the axial length of the inner tube 21. The separator tube 22 is coaxially arranged with the inner tube 21 and the outer shell 23, and is separated from the outer shell 23 at a radial position between the inner tube 21 and the outer shell 23.

[0026] The separating tube 22 has a first joint 31 at one axial end, a second joint 32 at the other axial end, and a main body 33 between these first joint 31 and second joint 32. The main body 33 is cylindrical with an inner diameter larger than the outer diameter of the inner tube 21. Both the first joint 31 and the second joint 32 are annular, and their inner diameters are smaller than the inner diameter of the main body 33. The separating tube 22 is fixed to the outer circumferential surface of the first joint 31 and the second joint 32 at a predetermined intermediate position in the axial direction of the inner tube 21. At this time, a first sealing ring 24 is provided between the first joint 31 and the inner tube 21 to seal between them, and a second sealing ring 25 is provided between the second joint 32 and the inner tube 21 to seal between them.

[0027] An intermediate chamber 41 is formed between the separating tube 22 and the inner tube 21. In the inner tube 21, near the engagement position of the first joint 31 between the engagement position of the first joint 31 and the engagement position of the second joint 32, a connecting hole 42 is formed that penetrates the inner tube 21 radially. The connecting hole 42 opens into the intermediate chamber 41.

[0028] In the separation tube 22, near the second joint 32 between the first joint 31 and the second joint 32, a cylindrical mounting port 45 is formed that protrudes radially outward from the main body 33. The inner portion of the mounting port 45 penetrates the separation tube 22 radially.

[0029] The outer casing 23 is a metal product. The outer casing 23 has a cylindrical part 51, a bottom part 52, and a fixing part 53.

[0030] The shell-shaped portion 51 is cylindrical. A transverse hole 55 is formed at one end of the shell-shaped portion 51 in the axial direction, which penetrates the shell-shaped portion 51 radially. The transverse hole 55 matches the mounting port 45 of the separator tube 22 in the axial and circumferential directions of the cylinder body 11.

[0031] The shell bottom 52 is fitted into the inner circumference of the end portion of the shell cylindrical portion 51 on one axial side. The shell bottom 52 closes the end portion of the shell cylindrical portion 51 on one axial side. The transverse hole 55 of the shell cylindrical portion 51 is disposed on the side of the shell bottom 52 closer to the axial center of the shell cylindrical portion 51.

[0032] The fixing part 53 bends radially inward from the end opposite to the bottom 52 of the shell cylindrical part 51 in the axial direction, and then expands vertically relative to the shell cylindrical part 51. The fixing part 53 is annular. Here, the axial end of a cylindrical component is plastically deformed by plastic processing such as rolling, thereby forming the shell cylindrical part 51 and the fixing part 53. The radially inward side of the fixing part 53 of the outer shell 23 becomes the opening 56 of 11.

[0033] The buffer 10 has a base component 61, a guide component 62, a first sealing component 63, a second sealing component 64, and a cover component 65.

[0034] The base component 61 is a metal product in the shape of a stepped ring. The base component 61 is placed on the shell bottom 52 inside the outer casing 23. The outer diameter of the axial end of the base component 61 opposite to the shell bottom 52 is a smaller diameter than the outer diameter of the portion on the shell bottom 52 side. One axial end of the inner tube 21 is fitted into this smaller diameter portion. Thus, the axial side of the inner tube 21 on the shell bottom 52 side is aligned with the center of the outer casing 23.

[0035] The guide member 62, the first sealing member 63, and the second sealing member 64 are all disposed within the cylindrical portion 51 of the outer casing 23 on the side opposite to the bottom 52 of the casing, i.e., on the side of the fixing portion 53. At this time, for the guide member 62, the first sealing member 63, and the second sealing member 64, the guide member 62 is disposed axially on the side closest to the bottom 52 of the casing in the cylinder body 11; the first sealing member 63 is disposed at the axial end of the guide member 62 on the side of the fixing portion 53; and the second sealing member 64 is disposed at the axial end of the first sealing member 63 on the side opposite to the guide member 62. The second sealing member 64, as a component disposed inside the cylinder body 11 of the buffer 10, is disposed on the outermost side.

[0036] The cover component 65 is disposed on the outer side of the cylinder body 11. The cover component 65 is disposed on the axial end of the outer shell 23 of the cylinder body 11 opposite to the bottom 52 of the shell, that is, on the side of the fixing part 53.

[0037] like Figure 2 As shown, the guide component 62 has a guide component body 71, a bushing 72, and a ring component 73.

[0038] The guide component body 71 is a metal product and is in the shape of a stepped annular ring. On one axial side, the guide component body 71 has a large-diameter portion 81 whose outer circumferential surface is formed of a cylindrical surface, and on the other axial side, it has a small-diameter portion 82 whose outer circumferential surface is formed of a cylindrical surface with a smaller diameter than the outer circumferential surface of the large-diameter portion 81. The large-diameter portion 81 and the small-diameter portion 82 are formed coaxially. The guide component body 71 is disposed within the shell-shaped portion 51 of the outer casing 23, with the large-diameter portion 81 positioned closer to the fixing portion 53 than the small-diameter portion 82 in the axial direction of the shell-shaped portion 51. Furthermore, the large-diameter portion 81 of the guide component body 71 fits into the inner circumferential surface of the shell-shaped portion 51 of the outer casing 23, and the small-diameter portion 82 fits into the inner tube 21 in the axial direction. Figure 1 The inner circumferential surface of the opposite end of the base component 61 shown. Thus, the axial opening 56 side of the inner tube 21 is aligned with the center of the outer casing 23.

[0039] For the inner tube 21, one axial end is supported by the base member 61, and the other axial end is supported by the guide member body 71 of the guide member 62. Thus, the inner tube 21 and the separation tube 22 are coaxially arranged relative to the outer casing 23. At this time, the inner tube 21 has a connecting hole 42 on the side closer to the guide member 62 than its axial center. Additionally, the separation tube 22 has a mounting port 45 on the side closer to the base member 61 than its axial center.

[0040] The inner tube 21 and the separation tube 22 form a liquid storage chamber 75 between the inner tube 21 and the outer shell 23. The liquid storage chamber 75 extends between the bottom 52 of the outer shell 23 and the base component 61 through a connecting groove 78 formed in the base component 61.

[0041] like Figure 2 As shown, an annular protrusion 83 protruding outward in an axial direction is formed at the end of the guide member body 71 on the side of the large diameter portion 81.

[0042] A segment 85 is formed at the end of the guide member body 71 on the side of the large diameter portion 81 in the axial direction. The segment 85 is located on the side of the small diameter portion 82 in the axial direction, which is located radially inward of the annular protrusion 83.

[0043] A connecting hole 84 is formed in the annular protrusion 83 and the segment 85, which axially penetrates the guide member body 71 at their respective junctions. The connecting hole 84 is located radially outward from the small diameter portion 82 and opens into the liquid storage chamber 75 between the outer casing 23 and the inner tube 21 on the axial side opposite to the annular protrusion 83 of the guide member body 71.

[0044] The bushing 72 is cylindrical. The bushing 72 covers at least the inner circumferential surface of the metal cylinder with a highly slippery material. The bushing 72 is fitted and fixed to the inner circumference of the small diameter portion 82 side of the guide member body 71 in the axial direction.

[0045] The ring component 73 is annular and is disposed on the inner periphery of the bushing 72 on the side of the larger diameter portion 81, which is axially closer to the bushing 72 of the guide component body 71.

[0046] The guide member 62 is a through hole 88 that passes through the guide member 62 axially on the radial inner side of the guide member body 71, bushing 72 and ring member 73.

[0047] The first sealing member 63 is annular. The first sealing member 63 is fitted into the inner circumferential surface of the shell cylindrical portion 51 of the outer casing 23 and abuts against the end of the guide member 62 on the axial fixing portion 53 side. The first sealing member 63 has a first retaining member 91, a first elastic member 92, an inner edge spring 93, and an outer edge spring 94.

[0048] The first retaining member 91 is a ring-shaped metal product. The first retaining member 91 is a planar shape with both ends expanding in the axial direction orthogonal to the axis, and the inner and outer circumferential surfaces are coaxial cylindrical surfaces.

[0049] The first elastic member 92 is made of a sealing elastic material such as rubber. The first elastic member 92 has an inner peripheral cover 101, an outer cover 102, an inner cover 103, an outer peripheral cover 104, an outer edge 105, an inner edge 106, a sealing ring 107, and a check flange 108. The first elastic member 92 is joined to the first retaining member 91 by vulcanization.

[0050] The inner circumferential cover 101 is cylindrical and is bonded to the inner circumferential surface of the first retaining member 91 in a manner that covers the inner circumferential surface of the first retaining member 91.

[0051] The outer cover 102 is flat and is bonded to the end face of the first retaining member 91 such that it covers the axial side of the end face, except for the radially outer portion. The outer cover 102 is continuous with the inner peripheral cover 101.

[0052] The inner cover 103 is flat and is bonded to the end face of the first retaining member 91 such that it completely covers the axial end face opposite to the outer cover 102. The inner cover 103 is continuous with the inner peripheral cover 101.

[0053] The outer peripheral cover 104 is cylindrical and is bonded to the outer peripheral surface of the first retaining member 91 in a manner that covers the outer peripheral surface of the first retaining member 91. The outer peripheral cover 104 is continuous with the inner cover 103.

[0054] The outer edge portion 105 is cylindrical and extends from the junction of the inner peripheral cover portion 101 and the outer peripheral cover portion 102 along the axial direction of the first retaining member 91 in a direction away from the first retaining member 91. The overall shape of the outer edge portion 105 is a tapered shape that becomes narrower towards the front end.

[0055] The inner edge portion 106 is cylindrical and extends from the junction of the inner peripheral cover portion 101 and the inner side cover portion 103 along the axial direction of the first retaining member 91 in a direction away from the first retaining member 91. The inner edge portion 106 extends in the opposite direction to the outer edge portion 105 relative to the first retaining member 91. The overall shape of the inner edge portion 106 is a tapered shape that narrows towards the front end.

[0056] The sealing ring portion 107 is annular and protrudes from the junction of the inner cover portion 103 and the outer peripheral cover portion 104 along the axial direction of the first retaining member 91 in a direction away from the first retaining member 91. The sealing ring portion 107 protrudes to the same side in the axial direction of the first retaining member 91 relative to the first retaining member 91 and the inner edge portion 106.

[0057] The check flange 108 is annular and extends radially from the inner edge 106 of the inner cover 103 and the sealing ring 107 toward the first retaining member 91 in an axial direction away from the first retaining member 91. The check flange 108 has an integral shape that expands towards the front end. The check flange 108 extends axially toward the first retaining member 91 on the same side as the inner edge 106 and the sealing ring 107.

[0058] The inner edge spring 93 is a metal ring-shaped clamping spring, which is installed on the outer periphery of the inner edge portion 106 of the first elastic member 92 and applies force to the inner edge portion 106 radially inward.

[0059] The outer edge spring 94 is a metal ring-shaped clamping spring, which is installed on the outer periphery of the outer edge portion 105 of the first elastic member 92 and applies force to the outer edge portion 105 radially inward.

[0060] The first sealing member 63 is located inside the cylindrical portion 51 of the outer casing 23, and is positioned closer to the fixing portion 53 than the axial guide member 62 of the cylindrical portion 51. At this time, the first sealing member 63 is in a state where the inner cover portion 103, the inner edge portion 106, the sealing ring portion 107, and the check flange portion 108 face the guide member 62.

[0061] The outer peripheral covering portion 104 of the first sealing member 63 is fitted into the inner peripheral surface of the shell-shaped portion 51 of the outer casing 23. The inner covering portion 103 of the first sealing member 63 abuts against the annular protrusion 83 of the guide member 62. The inner edge portion 106 of the first sealing member 63 enters the through hole 88 of the guide member 62. The sealing ring portion 107 of the first sealing member 63 is in close contact with the annular protrusion 83 of the guide member 62 and the shell-shaped portion 51 of the outer casing 23. The anti-reverse flange portion 108 of the first sealing member 63 abuts against the section portion 85 of the guide member 62. For the first sealing member 63, the sealing ring portion 107 mainly seals the radial gap between the guide member 62 and the outer casing 23. The outer edge portion 105 of the first sealing member 63 extends axially toward the outer casing 23 on the side opposite to the bottom 52 of the casing.

[0062] The second sealing component 64 is annular and fits into the inner circumferential surface of the shell cylindrical portion 51 of the outer casing 23, abutting against the first sealing component 63 and the fixing portion 53 of the outer casing 23.

[0063] The second sealing member 64 has a second retaining member 111 and a second elastic member 112.

[0064] The second retaining member 111 is a ring-shaped metal product. The second retaining member 111 is a planar shape with both ends expanding in a direction orthogonal to the axis, and the inner and outer circumferential surfaces are coaxial cylindrical surfaces. Compared with the first retaining member 91, the inner diameter of the second retaining member 111 is larger.

[0065] The second elastic member 112 is made of a sealing elastic material such as rubber, and has an inner circumferential cover 121, an outer circumferential cover 122, and a dustproof edge 123. The second elastic member 112 is joined to the second retaining member 111 by vulcanization.

[0066] The inner circumferential cover 121 is cylindrical and is bonded to the inner circumferential surface of the second retaining member 111 in such a way that it covers the inner circumferential surface of the second retaining member 111.

[0067] The outer cover 122 is flat and is adhered to the end face of the second retaining member 111 such that it covers the end face of one axial side, except for its radially outer portion. The outer cover 122 is continuous with the inner peripheral cover 121.

[0068] The dustproof edge 123 is cylindrical, extending axially from the junction of the inner peripheral cover 121 and the outer cover 122 of the second retaining member 111, and radially away from the second retaining member 111. The dustproof edge 123 has an integral shape that narrows towards the second retaining member 111 as it moves away from it. The dustproof edge 123 also becomes thinner radially away from the second retaining member 111, and thinner axially as it moves away from it.

[0069] The second sealing member 64 is disposed inside the cylindrical portion 51 of the outer casing 23 on the axial side of the cylindrical portion 51, closer to the fixing portion 53 than the first sealing member 63. At this time, the second sealing member 64 is in a state in which the outer covering portion 122 and the dustproof edge portion 123 face the side opposite to the first sealing member 63.

[0070] The second sealing member 64 is fitted into the shell-shaped portion 51 within the second retaining member 111. The second sealing member 64 abuts against the outer cover portion 102 of the first elastic member 92 of the first sealing member 63 within the second retaining member 111.

[0071] Here, before the fixing part 53 is formed, the guide member 62, the first sealing member 63, and the second sealing member 64 are fitted into the cylindrical portion 51 of the outer shell 23, which is cylindrical on the open side, from the opening on the axial side of the outer shell 23 opposite to the bottom 52 of the shell, in the order of guide member 62, first sealing member 63, and second sealing member 64. Then, the open side of the outer shell 23 is bent radially inward by plastic processing such as rolling to form the cylindrical portion 51 and the fixing part 53. Thus, the radially outer portion of the second sealing member 64 on the axial side of the end face of the second retaining member 111 opposite to the guide member 62, i.e., the metal portion, abuts against the fixing part 53. Therefore, the fixing part 53 of the outer shell 23 inhibits the axial movement of the second sealing member 64 towards the side opposite to the bottom 52 of the shell. In other words, the cylinder 11 becomes a fixing part 53 that inhibits the axial movement of the second sealing member 64 by bending its axial end radially inward. The dustproof edge 123 of the second sealing component 64 protrudes slightly in the axial direction of the outer casing 23 on the side opposite to the bottom 52 of the casing.

[0072] The cover component 65 is a one-piece molded product made of synthetic resin, and includes a cover bottom 131 (bottom), a cover cylinder 132 (cylinder), an abutment portion 133, a groove 134, and a connecting passage 135. The cover component 65 may be a metal product.

[0073] The bottom 131 of the cover has a through hole 141 extending axially through the center of the radial direction, forming a perforated circular plate.

[0074] The cap cylinder portion 132 is a cylindrical shape that extends to one side from the outer periphery of the cap bottom 131 along the axial direction of the cap bottom 131.

[0075] The abutment portion 133 extends axially from the cap cylinder portion 132 on one side of the cap bottom 131, and its end face protrudes along the same axial direction as the cap cylinder portion 132. The outer diameter of the abutment portion 133 is smaller than the inner diameter of the cap cylinder portion 132, and it is coaxially arranged with the cap cylinder portion 132. Therefore, the abutment portion 133 is separated from the cap cylinder portion 132 radially inside the cap bottom 131. The inner diameter of the axial end face of the abutment portion 133 on the opposite side of the cap bottom 131 is smaller than the outer diameter of the outer cover portion 122 of the second sealing member 64, while the outer diameter of this end face is larger than the outer diameter of the outer cover portion 122 of the second sealing member 64.

[0076] A through hole 141 is formed axially through the bottom 131 of the cover and the abutment portion 133. The end of the through hole 141 located on the axial abutment portion 133 side is a tapered shape with the diameter increasing towards the end side.

[0077] A groove 134 is disposed between the radially extending cap sleeve portion 132 and the abutment portion 133. The groove 134 is formed by the cap bottom 131, the cap sleeve portion 132, and the abutment portion 133. The groove 134 is recessed from the end of the abutment portion 133 on the side opposite to the cap bottom 131 in the axial direction. The groove 134 is circular in shape and coaxial with the cap sleeve portion 132 and the abutment portion 133.

[0078] The connecting passage 135 has a radial passage portion 151 and an axial passage portion 152.

[0079] A radial passage portion 151 is formed recessed from the cover cylinder portion 132 side towards the side opposite to the cover cylinder portion 132 on the axial side of the cover bottom 131. Thus, the radial passage portion 151 opens towards the cover cylinder portion 132 side of the cover bottom 131. The radial passage portion 151 extends radially along the cover bottom 131, with one end in the longitudinal direction opening into the through hole 141 and the other end extending to a midpoint radially inner side of the cover cylinder portion 132. The radial passage portion 151 penetrates the abutment portion 133 radially and axially. The radial passage portion 151 opens axially towards the side opposite to the cover bottom 131 of the abutment portion 133. The radial passage portion 151 is deeper than the groove portion 134 in terms of the depth of the end face opposite to the cover bottom 131 in the axial direction of the abutment portion 133. The radial passage portion 151 penetrates the groove portion 134 radially and axially.

[0080] An axial passage portion 152 is formed recessed from the radially inward side to the radially outward side on the inner circumferential side of the cover portion 132. Thus, the axial passage portion 152 opens radially inward toward the cover portion 132. The axial passage portion 152 extends axially along the cover portion 132, with one end in the longitudinal direction communicating with the radial passage portion 151, and the other end in the longitudinal direction opening toward the axial end of the cover portion 132 opposite to the bottom of the cover 131.

[0081] The connecting path 135, formed by connecting the radial passage 151 and the axial passage 152, traverses the groove 134 radially and axially.

[0082] For the cover component 65, the inner diameter of the cover cylinder portion 132 is smaller than the outer diameter of the portion of the outer shell 23 of the cylinder body 11 that accommodates the cover cylinder portion 132, i.e., the outer diameter of the portion of the shell cylindrical portion 51 that accommodates the cover cylinder portion 132, by a corresponding amount of interference fit. The outer diameter of the abutment portion 133 of the cover component 65 is smaller than the inner diameter of the fixing portion 53 of the outer shell 23. In other words, the diameter of the radially inner wall of the groove portion 134 of the cover component 65 is smaller than the inner diameter of the fixing portion 53. For the cover component 65, the protrusion height of the abutment portion 133 from the cover bottom 131, i.e., the depth of the groove portion 134, is greater than the axial thickness of the fixing portion 53.

[0083] The cover member 65 is fitted by pressing the outer periphery of the axial end of the shell-shaped portion 51 of the outer casing 23 of the cylinder body 11, opposite to the bottom 52 of the casing, into the radially inner side of the cover cylinder portion 132. Thus, the cover cylinder portion 132 of the cover member 65 abuts against the radially outer side of the cylinder body 11, and the abutting portion 133 protruding from the bottom 131 abuts against the outer covering portion 122 of the second sealing member 64. In other words, the second sealing member 64 is provided with a second elastic member 112 including the deformable outer covering portion 122 that abuts against the abutting portion 133. In this state, the groove 134 of the cover member 65 accommodates the fixing portion 53 of the outer casing 23. In other words, the cover member 65 allows the fixing portion 53 of the outer casing 23 to enter within the radial and axial range of the groove 134. Furthermore, in this state, the cover member 65 allows the dustproof edge portion 123 of the second sealing member 64 to enter the through hole 141 with a radial gap.

[0084] Here, the depth of the groove 134 is greater than the axial thickness of the fixing part 53. Therefore, the bottom surface of the groove 134 on the axial side of the cover bottom 131 is separated from the end of the fixing part 53 on the axial side opposite to the shell bottom 52. In other words, the groove 134 is formed such that it is separated from the end of the fixing part 53 between the cover cylinder part 132 and the abutment part 133. Thus, an axial gap is provided within the groove 134 between the bottom surface of the groove 134 and the fixing part 53.

[0085] like Figure 1As shown, the buffer 10 includes a piston 180 that is inserted into the cylinder 11. The piston 180 is slidably disposed within the inner tube 21 of the cylinder 11. In other words, the inner tube 21 guides the movement of the piston 180. The piston 180 divides the inner tube 21 of the cylinder 11 into two chambers: a first chamber 181 and a second chamber 182. The first chamber 181 is disposed between the piston 180 and the guide member 62 in the axial direction of the inner tube 21. The first chamber 181 is in continuous communication with the intermediate chamber 41 via a communication hole 42 formed in the inner tube 21. The second chamber 182 is disposed between the piston 180 and the base member 61 in the axial direction of the inner tube 21. The second chamber 182 is separated from the reservoir chamber 75 by the base member 61.

[0086] Inside the cylinder 11, the first chamber 181 and the second chamber 182 in the inner tube 21, and the intermediate chamber 41 in the separation tube 22 are sealed with oil L, which serves as the working fluid. Inside the cylinder 11, the reservoir 75 is sealed with oil L and gas G, which also serve as the working fluid.

[0087] The buffer 10 includes a piston rod 190. A first end of the piston rod 190, located axially, is disposed within the inner tube 21 of the cylinder 11. The first end of the piston rod 190 is connected to a piston 180. A second end of the piston rod 190, located axially opposite to the first end, protrudes from the cylinder 11 toward the outside of the cylinder 11.

[0088] The piston rod 190 has a main shaft portion 191 and a mounting shaft portion 192. The outer diameter of the mounting shaft portion 192 is smaller than the outer diameter of the main shaft portion 191. The mounting shaft portion 192 is located at the first end of the piston rod 190 and is disposed within the inner tube 21. Figure 2 As shown, the main shaft portion 191 of the piston rod 190 axially passes through the guide member 62, the first sealing member 63, and the second sealing member 64, all disposed within the cylinder body 11, and axially passes through the bottom 131 of the cover member 65 mounted on the outside of the cylinder body 11. At this time, the piston rod 190 is inserted into the guide member 62 through the through hole 88. Additionally, the cover member 65 is inserted into and passes through the through hole 141. The bushing 72 of the guide member 62 slides in contact with the main shaft portion 191 and guides the axial movement of the piston rod 190.

[0089] The first sealing member 63 is inserted into and passes through the main shaft portion 191 of the piston rod 190 radially inward of the inner peripheral cover portion 101, the outer edge portion 105, and the inner edge portion 106. A gap exists between the main shaft portion 191 of the piston rod 190 and the inner peripheral cover portion 101 of the first sealing member 63, and it contacts the inner edge portion 106 and the outer edge portion 105. The main shaft portion 191 of the piston rod 190 is slidable between the inner edge portion 106 and the outer edge portion 105 of the first sealing member 63. An inner edge spring 93 pushes the inner edge portion 106 towards the main shaft portion 191 of the piston rod 190, and an outer edge spring 94 pushes the outer edge portion 105 towards the main shaft portion 191 of the piston rod 190.

[0090] The second sealing member 64 is located inside the dustproof edge portion 123, allowing the main shaft portion 191 of the piston rod 190 to slide into and pass through it.

[0091] The second sealing member 64 prevents rainwater or foreign objects from entering the cylinder body 11 through the opening 56 of the outer casing 23. The second sealing member 64 slides in contact with the main shaft portion 191 of the piston rod 190 via the dustproof flange 123, thereby scraping away rainwater or foreign objects adhering to the main shaft portion 191. Thus, the second sealing member 64 prevents rainwater or foreign objects from entering the cylinder body 11 through the gap between the second sealing member 64 and the main shaft portion 191.

[0092] The first sealing member 63 prevents rainwater or foreign objects from entering the cylinder body 11 through the second sealing member 64. The first sealing member 63 slides in contact with the main shaft portion 191 of the piston rod 190 via its outer edge 105, thereby scraping away rainwater or foreign objects adhering to the main shaft portion 191. Thus, the first sealing member 63 prevents rainwater or foreign objects from entering the cylinder body 11 through the gap between the first sealing member 63 and the main shaft portion 191.

[0093] Furthermore, the first sealing member 63 suppresses the leakage of oil L and gas G from the cylinder body 11 to the outside of the cylinder body 11. The first sealing member 63 slides in contact with the main shaft portion 191 of the piston rod 190 through its inner edge portion 106, thereby scraping away the oil L adhering to the main shaft portion 191 inside the cylinder body 11. Thus, the first sealing member 63 suppresses the leakage of oil L to the outside of the cylinder body 11 through the gap between the first sealing member 63 and the main shaft portion 191.

[0094] like Figure 1 As shown, a piston 180 is mounted on a mounting shaft 192 in the piston rod 190. The piston 180 moves integrally with the piston rod 190.

[0095] Piston 180 has axially extending passages 201 and 202. Both passages 201 and 202 connect the first chamber 181 and the second chamber 182.

[0096] The buffer 10 is equipped with disc valve 203 and disc valve 204.

[0097] The disc valve 203 is located on the axial side of the piston 180 opposite to the bottom of the housing 52. The disc valve 203 can close the passage 201 by abutting against the piston 180.

[0098] Disc valve 204 is disposed on the bottom 52 side of the housing in the axial direction of piston 180. Disc valve 204 can close passage 202 by abutting against piston 180. Disc valve 203 and disc valve 204 are mounted together with piston 180 to mounting shaft 192 of piston rod 190 by nut 205.

[0099] During the compression stroke, when the piston rod 190 increases the amount of fluid entering the cylinder 11 and moves towards the compression side, the disc valve 203 opens the passage 201 to allow oil L to flow from the second chamber 182 to the first chamber 181 when the piston 180 moves towards the direction of narrowing the second chamber 182 and the pressure in the second chamber 182 is higher than the pressure in the first chamber 181 by a predetermined value. At this time, the disc valve 203 generates a damping force. At least one of the piston 180 and the disc valve 203 is provided with a throttling orifice (not shown) that allows communication between the first chamber 181 and the second chamber 182 via the passage 201 even when the disc valve 203 completely closes the passage 201.

[0100] During the extension stroke of the piston rod 190, which increases its protrusion from the cylinder 11 and moves towards the extension side, the disc valve 204 opens the passage 202 to allow oil L to flow from the first chamber 181 to the second chamber 182 when the piston 180 moves towards the direction of narrowing the first chamber 181 and the pressure in the first chamber 181 is higher than the pressure in the second chamber 182 by a predetermined value. At this time, the disc valve 204 generates a damping force. At least one of the piston 180 and the disc valve 204 is provided with a throttling orifice (not shown) that allows communication between the first chamber 181 and the second chamber 182 via the passage 202 even when the disc valve 204 is in a state of complete closure of the passage 202.

[0101] The buffer 10 includes a base valve 210 comprising the aforementioned base component 61.

[0102] The base component 61 has axially extending passages 211 and 212. Both passages 211 and 212 connect the second chamber 182 to the liquid storage chamber 75.

[0103] The base valve 210 has an annular disc valve 213 on the axial side of the base member 61 opposite to the second chamber 182, which can close the passage 211 by abutting against the base member 61. Furthermore, the base valve 210 has an annular disc valve 214 on the axial side of the base member 61 opposite to the second chamber 182, which can close the passage 212 by abutting against the base member 61. The base valve 210 has a fastening member 215, through which the disc valves 213 and 214 are mounted to the base member 61. The base member 61, the fastening member 215, and the disc valves 213 and 214 constitute the base valve 210.

[0104] During the compression stroke of the base valve 210, when the piston rod 190 moves towards the compression side and the piston 180 moves towards the shrinking second chamber 182, if the pressure in the second chamber 182 is higher than the pressure in the reservoir 75 by a predetermined value, the disc valve 213 opens passage 211 to allow oil L to flow from the second chamber 182 to the reservoir 75. At this time, the disc valve 213 generates a damping force. During the extension stroke of the base valve 210, when the piston rod 190 moves towards the extension side and the piston 180 moves towards the first chamber 181, if the pressure in the second chamber 182 is lower than the pressure in the reservoir 75, the disc valve 214 opens passage 212 to allow oil L to flow from the reservoir 75 to the second chamber 182. At this time, the disc valve 214 is a suction valve that allows oil L to flow from the reservoir 75 to the second chamber 182 without generating substantial damping force.

[0105] The buffer 10 has a damping force adjustment mechanism 221.

[0106] The damping force adjustment mechanism 221 is mounted on the outside of the shell-shaped portion 51 of the outer casing 23 in a manner that surrounds the transverse hole 55. The damping force adjustment mechanism 221 protrudes outward from the outer casing 23 radially. The damping force adjustment mechanism 221 closes the transverse hole 55 of the shell-shaped portion 51 by being mounted on the shell-shaped portion 51. The damping force adjustment mechanism 221 has a cylindrical inner communication port 225 that passes through the transverse hole 55 of the outer casing 23, protrudes into the shell-shaped portion 51, and fits into the mounting port 45 of the separation tube 22. The damping force adjustment mechanism 221 has an outer communication port 226 that is located radially outward compared to the inner communication port 225 and opens outward compared to the inner communication port 225 in the transverse hole 55 of the outer casing 23.

[0107] The inner connecting port 225 of the damping force adjustment mechanism 221 communicates with the first chamber 181 via the intermediate chamber 41 in the separation tube 22 and the passage formed in the connecting hole 42 of the inner tube 21. The outer connecting port 226 of the damping force adjustment mechanism 221 communicates with the reservoir 75. The damping force adjustment mechanism 221 has a solenoid 231 controlled by an electrical signal transmitted via wiring (not shown). Controlling the solenoid 231 adjusts the amount of communication between the inner connecting port 225 and the outer connecting port 226. As a result, the damping force adjustment mechanism 221 adjusts the amount of communication between the intermediate chamber 41 in the separation tube 22, the passage in the connecting hole 42 of the inner tube 21, and the first chamber 181 and the reservoir 75. That is, the damping force adjustment mechanism 221 adjusts the amount of communication between the first chamber 181 and the reservoir 75 by electric drive, thereby adjusting the damping force generated by the buffer 10.

[0108] In the damper 10, the bottom 52 of the outer shell 23 of the cylinder 11 is located at the lower part and connected to the wheel side (not shown in the schematic diagram of the vehicle), while the portion extending from the cylinder 11 of the piston rod 190 is located at the upper part and connected to the body side (not shown in the schematic diagram of the vehicle). Thus, the damper 10 dampens the relative vibration between the wheel and the vehicle body.

[0109] Here, when the buffer 10 is connected to the wheel side (illustrated in the omitted figure) and the body side (illustrated in the omitted figure), as... Figure 2 As shown by the double-dotted line, a corrugated rubber buffer 241, which allows the piston rod 190 to be inserted and penetrated, is disposed between the bottom 131 of the cover member 65 and the buffer rubber support part of the vehicle body (not shown). The buffer rubber 241 surrounds the through hole 141 of the bottom 131 of the cover and abuts against the bottom 131 of the cover. The cover member 65 protects the second sealing member 64 from the influence of the buffer rubber 241.

[0110] When the distance between the buffer 10 and the vehicle body side (not shown in the diagram) decreases, the extension of the piston rod 190 from the cylinder 11 decreases. As a result, the corrugated buffer rubber 241 located between the cover member 65 and the buffer rubber support part (not shown in the diagram) undergoes elastic deformation by being pushed by the buffer rubber support part and the bottom of the cover 131 and contracting axially.

[0111] At this time, in the cover member 65, the cover bottom 131 is subjected to an axial external force from the cushioning rubber 241 toward the shell bottom 52. When subjected to such an external force, the cover member 65 elastically deforms the outer covering portion 122 of the second elastic member 112 of the second sealing member 64 in a manner of axial compression, while the radially inner portion and the abutment portion 133 of the cover bottom 131 elastically deform in the axial direction in a manner of moving toward the shell bottom 52.

[0112] As the magnitude of the external force applied from the cushioning rubber 241 to the bottom of the cover 131 further increases, the cover component 65 elastically deforms in the axial direction by causing the second retaining member 111 of the second sealing member 64 to move its radially inner portion toward the bottom of the shell 52, elastically deforming the outer covering portion 102 of the first sealing member 63 to be compressed axially, elastically deforming the first retaining member 91 of the first sealing member 63 to move its radially inner portion toward the bottom of the shell 52, and elastically deforming the inner covering portion 103 of the first sealing member 63 to be compressed axially, while also causing the radially inner portion and the abutment portion 133 of the bottom of the cover 131 to move further toward the bottom of the shell 52.

[0113] Here, because the bottom surface of the groove 134 and the axial end of the fixing part 53 of the outer shell 23 opposite to the bottom 52 of the shell are axially separated, if the axial external force from the cushioning rubber 241 is less than a specified value, the deformation of the above-mentioned parts is small, and thus the bottom surface of the groove 134 and the fixing part 53 of the outer shell 23 can be suppressed from axially abutting.

[0114] When the axial external force from the cushioning rubber 241 on the cover member 65 is below a predetermined value, the deformation of the aforementioned parts is small. As a result, the bottom surface of the groove 134 of the cover member 65 can be kept axially separated from the fixing part 53 of the outer shell 23. In this state, the axial external force from the cushioning rubber 241 is borne by the cover bottom 131 and abutment part 133 of the cover member 65, the outer cover part 122 and the second retaining part 111 of the second elastic part 112 of the second sealing part 64, the outer cover part 102 of the first sealing part 63, the second retaining part 111 and the inner cover part 103, the guide part 62, the inner tube 21, the base part 61, and the outer shell 23. The second sealing part 64 supports the cover member 65 and bears the load from the cushioning rubber 241, i.e., the cushioning load.

[0115] When the axial external force from the cushioning rubber 241 on the cover member 65 exceeds a predetermined value, the deformation of the aforementioned parts increases. As a result, the bottom surface of the groove 134 of the cover member 65 abuts against the fixing part 53 of the outer casing 23 in the axial direction. Thus, the axial external force from the cushioning rubber 241 is borne by the bottom 131 of the cover member 65 and the outer casing 23. That is, the cover member 65 deforms when the bottom 131 of the cover is subjected to the axial external force, allowing the bottom surface of the groove 134 to abut against the fixing part 53 of the cylinder body 11.

[0116] Here, regardless of whether the bottom surface of the groove 134 and the fixing part 53 of the cylinder 11 are axially abutting, the connecting passage 135 formed by the cover member 65 connects between the through hole 141 of the cover bottom 131 and the cover cylinder 132 and the shell-shaped part 51 of the outer shell 23 of the cylinder 11. As a result, when the bellows-shaped cushioning rubber 241 is compressed, the air discharged from the cushioning rubber 241 into the through hole 141 of the cover bottom 131 can be discharged outward from between the cover cylinder 132 and the shell-shaped part 51 via the connecting passage 135.

[0117] Patent Document 1 discloses a structure in which, in addition to a sealing member sealing between the cylinder and piston rod, a sealing member sealing between a cover member and piston rod is pressed into a cover member located at the axial end of the cylinder. However, in this structure, there is a possibility that the load from the cushioning rubber may cause the cover member to deform, or that the sealing member on the cover member may detach due to the sliding of the piston rod. Patent Document 2 discloses a structure in which multiple sealing members sealing between the cylinder and piston rod are provided in the buffer. In this buffer, no cover member is provided at the axial end of the cylinder. Patent Documents 3 and 4 disclose buffers with one sealing member sealing between the cylinder and piston rod. Patent Document 5 discloses a buffer with two sealing members sealing between the cylinder and piston rod. In this buffer, no cover member is provided. However, it is desirable to improve the reliability of the buffer.

[0118] The buffer 10 of this embodiment includes: a guide member 62 disposed within the housing 23 of the cylinder 11 and into which a piston rod 190 is inserted; a first sealing member 63 abutting against the guide member 62 and disposed at the axial end of the guide member 62; and a second sealing member 64 abutting against the first sealing member 63 and disposed at the axial end of the first sealing member 63 located on the opposite side to the guide member 62. Thus, the buffer 10 can prevent rainwater or foreign objects from entering the cylinder 11 through the first sealing member 63 and the second sealing member 64.

[0119] Furthermore, the buffer 10 suppresses axial movement of the second sealing member 64 by means of a fixing portion 53 that bends radially inward at the axial end of the cylinder body 11. Thus, even if the buffer 10 is subjected to external force from the buffer rubber 241, and even if the piston rod 190 slides relative to the second sealing member 64, the second sealing member 64 can be prevented from falling off. Moreover, since the second sealing member 64 can be supported on the cylinder body 11 at the metal second retaining member 111, the dustproof edge 123 can be stably contacted with the piston rod 190. Therefore, the buffer 10 also improves the scraping effect of the dustproof edge 123 on foreign matter adhering to the piston rod 190.

[0120] Furthermore, for the buffer 10, the cover member 65 includes: a cover bottom 131 having a through hole 141 through which the piston rod 190 is inserted; a cover cylinder 132 abutting against the radially outer side of the cylinder body 11; an abutting portion 133 protruding from the cover bottom 131 and abutting against the second sealing member 64; and a groove 134 formed between the cylinder 132 and the abutting portion 133, separated from the end of the fixing portion 53 of the cylinder body 11. For the buffer 10, the groove 134 of the cover member 65 is separated from the fixing portion 53 of the cylinder body 11 in this way, which can suppress axial abutment between the groove 134 of the cover member 65 and the fixing portion 53 of the cylinder body 11 under normal external force from the buffer rubber 241. Thus, the buffer 10 can suppress damage to the cover member 65 caused by repeated abutment between the groove 134 of the cover member 65 and the fixing portion 53 of the cylinder body 11. Furthermore, since the second sealing member 64, which has a larger pressure-bearing area relative to the cover member 65, withstands the usual external force from the cushioning rubber 241, the stress generated on the cover member 65 can be reduced, and damage to the cover member 65 can be further suppressed.

[0121] Based on the above scheme, the reliability of buffer 10 can be improved.

[0122] For the buffer 10, since the cover part 65 is made of synthetic resin, it is possible to achieve a lightweight design. When the cover part 65 is made of synthetic resin, it is disadvantageous in terms of strength compared to the case of metal, so the effect achieved by the above structure is better.

[0123] For the buffer 10, when the cover member 65 is subjected to an axial external force at the bottom 131 of the cover, the groove 134 abuts against the fixing part 53 of the cylinder body 11. Therefore, even when the buffer 10 is subjected to a large external force from the cushioning rubber 241, the cylinder body 11 can withstand that force. Thus, the buffer 10 can suppress excessive deformation of the cover member 65, and can suppress damage to the cover member 65, the first sealing member 63, the second sealing member 64, and the guide member 62 caused by this deformation. Therefore, the reliability of the buffer 10 can be further improved.

[0124] When the bottom 131 of the cover member 65 of the buffer 10 is subjected to an axial external force, the second elastic member 112 of the second sealing member 64, which abuts against the abutment portion 133, deforms. As a result, the buffer 10 can easily deform the cover member 65 under the condition of being subjected to a large external force from the buffer rubber 241, so that the groove portion 134 abuts against the fixing portion 53 of the cylinder body 11.

[0125] For the buffer 10, regardless of whether the bottom surface of the groove 134 abuts against the fixing part 53 of the cylinder 11, the connecting passage 135 formed in the cover member 65 connects the through hole 141 of the cover bottom 131 with the cover cylinder 132 and the shell-shaped part 51 of the cylinder 11. Therefore, for the buffer 10, air discharged from the buffer rubber 241 into the through hole 141 of the cover bottom 131 during compression can be discharged outward from between the cover cylinder 132 and the shell-shaped part 51 via the connecting passage 135. As a result, for the buffer 10, excessive pressure increase on the second sealing member 64 caused by the buffer rubber 241 being introduced into the through hole 141 of the cover bottom 131 during compression can be prevented. Therefore, for the buffer 10, the durability of the second sealing member 64 can be improved.

Claims

1. A buffer, characterized in that, have: Cylinder block; A piston that is slidably disposed within the cylinder, dividing the cylinder into two chambers; A piston rod, the first end of which is connected to the piston, and the second end of which protrudes from the cylinder body; A guide component, disposed within the cylinder body, has a through hole for insertion of the piston rod; A first sealing member abuts against the guide member and is disposed at the axial end of the guide member; The second sealing member abuts against the first sealing member and is disposed at the axial end of the first sealing member on the opposite side of the guide member; A cover component, which is disposed at the axial end of the cylinder body; The axial end of the cylinder body becomes a fixed part that bends radially inward to inhibit the axial movement of the second sealing member. The cover component includes: a bottom having a through hole through which the piston rod is inserted; a cylindrical portion abutting against the radially outer side of the cylinder; an abutting portion protruding from the bottom and abutting against the second sealing component; and a groove formed between the cylindrical portion and the abutting portion in a manner separate from the end of the fixing portion.

2. The buffer according to claim 1, characterized in that, When the cover component is subjected to an axial external force at the bottom, it deforms in such a way that the groove and the fixing part can abut against each other.

3. The buffer according to claim 2, characterized in that, The second sealing component is provided with an elastic component that abuts against the abutting portion and is deformable. When the bottom is subjected to an axial external force, the elastic component deforms.

4. The buffer according to claim 2, characterized in that, The cover component has a communication path that connects the bottom through hole to the cylindrical part and the cylinder body regardless of whether the groove and the fixing part abut against each other.

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