Shock absorber

Abstract

Provided is a shock absorber comprising a guide member which can pass through a swaging part formed in an outer tube. This shock absorber comprises: a fixing part 31 fixed to the outer circumference of an inner tube 2; a plurality of extension parts 41 extending from the other end of the fixing part 31 in the axial direction of the cylinder; and a guide member 30 having a rounded-shaped swelling part 43 formed at the longitudinal central part of each of the extension parts 41 and brought into contact with the inner circumferential surface 23 of the outer tube 3. When the inner tube 2 to which the guide member 30 is attached is assembled in the outer tube 3, the guide member 30 can pass through a swaging part 25, which is formed in the outer tube 3, by elastically deforming each of the extension parts 41 inward in the radial direction of the cylinder to thereby reduce the diameter of the guide member 30.

Description

buffer

[0001] The present invention relates to a shock absorber that is applied to a suspension device of a vehicle.

[0002] Patent Document 1 discloses a shock absorber in which, when a cylinder assembly formed by attaching a bottom piece 11 to the lower end of an inner tube 2 is assembled into an outer tube 1, the cylinder assembly is centered relative to the outer tube 1 using a centering member 17 (guide member) fastened together with the bottom piece 11 (base valve).

[0003] Japanese Utility Model Application Publication No. 07-016043 Japanese Patent Application Publication No. 2017-032060

[0004] In a shock absorber having a swaging portion (reduced diameter portion) at the end of the outer tube on the rod guide side (see, for example, Patent Document 2), when the cylinder assembly is assembled into the outer tube, the guide member protruding radially outward from the inner tube gets caught on the swaging portion formed on the outer tube and cannot pass through the swaging portion.

[0005] An object of the present invention is to provide a shock absorber having a guide member that can pass through a swaging portion formed on an outer tube.

[0006] The shock absorber of the present invention has a fixed portion fixed to the outer periphery of a first cylinder, a plurality of extension portions extending from the fixed portion, and a second cylinder abutment portion formed on a part of the extension portion and abutting against a second cylinder, and is equipped with a guide member that elastically deforms the extension portions to bias the first cylinder and the second cylinder radially apart.

[0007] According to one embodiment of the present invention, it is possible to provide a shock absorber having a guide member that can pass through a swaging portion formed on an outer tube.

[0008] 8 is a diagram showing a cross section of a portion of the shock absorber 1 according to the first embodiment, taken along an axial plane. FIG. 1 is an explanatory diagram of the first embodiment, showing a plan view of a guide member. FIG. 2 is an explanatory diagram of the first embodiment, showing a front view of the guide member. FIG. 3 is an explanatory diagram of the first embodiment, showing a cross section showing a state in which an inner tube to which a guide member is fixed is inserted into an outer tube. The guide member is shown in cross section A-A in FIG. 2. FIG. 4 is an explanatory diagram of the first embodiment, showing the operation of the guide member. FIG. 5 is an explanatory diagram of the second embodiment, showing a plan view of the guide member. FIG. 6 is an explanatory diagram of the second embodiment, showing a cross section showing a state in which an inner tube to which a guide member is fixed is inserted into an outer tube. The guide member is shown in cross section B-B in FIG. 8. FIG. 9 is an explanatory diagram of the fourth embodiment.

[0009] A first embodiment of the present invention will be described with reference to the accompanying drawings. As shown in Fig. 1, a shock absorber 1 has a twin-cylinder structure in which an outer tube 3 (second cylinder) is provided around an inner tube 2 (first cylinder). A reservoir chamber 4 is formed between the inner tube 2 and the outer tube 3. The inner tube 2 and the outer tube 3 are arranged coaxially (concentrically). Where necessary, the inner tube 2 or the outer tube 3 will be referred to as a cylinder.

[0010] The shock absorber 1 has a piston 5 that is slidably fitted within the inner tube 2 and divides the interior of the inner tube 2 into two chambers, a first chamber 2A and a second chamber 2B. The shock absorber 1 has a piston rod 6 whose one end (the "lower side" in FIG. 1 ) is connected to the piston 5 and whose other end (the "upper side" in FIG. 1 ) passes through the first chamber 2A and extends from the cylinder (the inner tube 2 and the outer tube 3) to the outside. The piston rod 6 is inserted into a rod guide 7 provided at the end of the other end of the cylinder. An oil seal 9 attached to a washer 8 seals the first chamber 2A from the outside.

[0011] A swaging portion 25 (recess) is formed by swaging at the other end (the "upper side" in FIG. 1 ) of the outer tube 3, i.e., the end from which the piston rod 6 extends. In other words, the swaging portion 25 is formed by deforming a portion of the other end of the outer tube 3 over the entire circumference toward the inside in the radial direction of the cylinder (outer tube 3). A rod guide fitting portion 19 into which the rod guide 7 is fitted is formed at the end of the outer tube 3 that is closer to the other end than the swaging portion 25.

[0012] The piston 5 is provided with an extension passage 11 and a compression passage 12 that connect the first chamber 2A and the second chamber 2B. One end of the extension passage 11 (the "lower side" in FIG. 1 ) is provided with a disk valve 13 (relief valve) that opens to release the pressure in the first chamber 2A to the second chamber 2B when the pressure in the first chamber 2A reaches a set pressure. On the other hand, the other end of the compression passage 12 (the "upper side" in FIG. 1 ) is provided with a disk valve 14 (check valve) that allows the flow of working fluid from the second chamber 2B to the first chamber 2A.

[0013] A base valve 10 is provided at one end (the "lower side" in FIG. 1 ) of the inner tube 2, separating the second chamber 2B from the reservoir chamber 4. The base valve 10 is provided with an extension passage 15 and a compression passage 16 that communicate between the second chamber 2B and the reservoir chamber 4. A disc valve 17 (check valve) that allows the flow of working fluid from the reservoir chamber 4 to the second chamber 2B is provided at the other end (the "upper side" in FIG. 1 ) of the extension passage 15. On the other hand, a disc valve 18 (relief valve) is provided at one end of the compression passage 16. The disc valve 18 opens to release the pressure in the second chamber 2B to the reservoir chamber 4 when the pressure in the second chamber 2B reaches a set pressure. Note that working fluid is sealed in the inner tube 2, and working fluid and gas are sealed in the reservoir chamber 4.

[0014] 2 to 4 , the guide member 30 has a cylindrical fixing portion 31 that is fixed by being press-fitted onto the outer periphery of the inner tube 2, a plurality of (four in the first embodiment) protruding portions 35 that protrude radially outward from the inner tube 2 from the lower end of the fixing portion 31 in FIG. 4 when the fixing portion 31 is fixed to the inner tube 2 (see FIG. 4 ), and a plurality of (six in the first embodiment) extending portions 41 that extend from the other end (the upper end in FIG. 4 ) of the fixing portion 31 when the fixing portion 31 is fixed to the inner tube 2 toward an opening on the other end side of the inner tube 2.

[0015] For convenience, in Fig. 4, the guide member 30 is positioned at a central position in the axial direction of the inner tube 2 (the "vertical direction" in Fig. 4), but in the state of the shock absorber 1 (see Fig. 1), the end (the "protrusion 35" in the first embodiment) of one end side (the "lower side" in Fig. 4) of the fixed portion 31 of the guide member 30 abuts against the base valve 10 (see Fig. 1). Also, in Fig. 4, the base valve 10 is omitted, and only the inner tube 2, the outer tube 3, and the guide member 30 are shown. Furthermore, Fig. 4 shows the guide member 30 in a cross section taken along line A-A in Fig. 2.

[0016] The guide member 30 is made of carbon steel pipe for mechanical construction (STKM). The thickness of the steel pipe (hereinafter referred to as "steel pipe") used as the material is, for example, 0.6 mm to 0.8 mm, but is not intended to be limited to this. The multiple protrusions 35 are formed by forming multiple claws at equal intervals in the circumferential direction on one end of the steel pipe (the "lower side" in FIG. 4) and bending each claw outward in the radial direction of the steel pipe. The multiple protrusions 35 are tool engagement portions when the fixing portion 31 of the guide member 30 is press-fitted onto the outer periphery of the inner tube 2.

[0017] The multiple extension portions 41 are formed by forming multiple strip-shaped claw portions at equal intervals in the circumferential direction on the other end side of the steel pipe (the "upper side" in FIG. 4 ), and the central portion (part) of each claw portion in the longitudinal direction (the "up-and-down direction" in FIG. 4 ) bulges outward in the radial direction of the steel pipe to form an R-shaped bulge portion 43. That is, the cross section of the extension portion 41 taken along a plane including the axis of the cylinder is formed into a wave shape (a shape convex outward in the radial direction of the cylinder). Furthermore, with the fixing portion 31 fixed to the inner tube 2 (see FIG. 4 ), the R portion 45 (first cylinder abutment portion) formed at the end on the other end of the extension portion 41 abuts against the outer circumferential surface 22 of the inner tube 2.

[0018] In the state of the shock absorber 1 (see FIG. 1 ), the R-shaped bulging portion 43 (second cylinder abutting portion) of the extending portion 41 abuts against the inner circumferential surface 23 of the outer tube 3. In other words, in the state where the fixing portion 31 of the guide member 30 is fixed to the inner tube 2 (see FIG. 4 ), the diameter of the cylinder inscribed with the bulging portion 43 of each extending portion 41 matches the inner diameter of the outer tube 3. As shown in FIG. 4 , in the state of the shock absorber 1, the end 46 (extending direction end) on the other end side of the extending portion 41 is spaced from the inner tube 2 and the outer tube 3, and the diameter D of the circle inscribed with the end 46 of each extending portion 41 is set to be smaller than the inner diameter d of the swaging portion 25 of the outer tube 3.

[0019] Next, the operation of the guide member 30 in the first embodiment will be described with reference to Figure 5. First, the fixing portion 31 of the guide member 30 is press-fitted onto the outer periphery of the inner tube 2 (first cylinder) from the other end side (the "upper side" in Figures 1 and 5) of the inner tube 2. At this time, the fixing portion 31 can be press-fitted onto the outer periphery of the inner tube 2 by pressing the multiple protrusions 35 of the guide member 30 into one end side (the "lower side" in Figures 1 and 5) of the inner tube 2 with a tool (not shown). Note that a base valve 10 is attached to the opening on one end side of the inner tube 2, but Figure 5 does not show the base valve 10 and only shows the inner tube 2, outer tube 3, and guide member 30.

[0020] Then, the end of one end of the inner tube 2 (the side to which the base valve 10 is fixed) to which the guide member 30 is fixed is inserted into the outer tube 3 from the opening at the other end (the "upper side" in FIG. 5 ) of the outer tube 3 (second cylinder). At this time, as the guide member 30 passes through the opening at the other end of the outer tube 3, the bulging portions 43 (second cylinder abutting portions) of each extension portion 41 are pushed radially inward of the cylinder by the inner circumferential surface 23 of the outer tube 3 (the guide member 30 is reduced in diameter), causing the guide member 30 to elastically deform.

[0021] Furthermore, in the process of the guide member 30 passing through the swaging portion 25 of the outer tube 3, i.e., in the process of the R-shaped bulging portion 43 of each extension portion 41 of the guide member 30 moving (sliding) along the inner circumferential surface 26 of the swaging portion 25, each extension portion 41 is elastically deformed as the bulging portion 43 is pushed radially inward of the cylinder by the swaging portion 25. In other words, the guide member 30 is reduced in diameter as each extension portion 41 is restrained by the swaging portion 25.

[0022] When the bulging portions 43 of the guide member 30 pass the swaging portion 25 of the outer tube 3, they are released from the constraint of the swaging portion 25 (the force pressing radially inward of the cylinder) and deform by their own elastic force, bulging radially outward of the cylinder, causing the bulging portions 43 to abut (be pressed against) the inner circumferential surface 23 of the outer tube 3. This makes it possible to center one end of the inner tube 2 (the "lower side" in FIG. 1 ) relative to the outer tube 3, and to seat the base valve 10 attached to one end of the inner tube 2 in a fixed position (center) on the bottom portion 20 of the outer tube 3.

[0023] In a shock absorber (hereinafter referred to as a "conventional shock absorber") equipped with a conventional guide member (centering member), when the inner tube (cylinder assembly) is assembled into the outer tube, the guide member protruding radially outward from the inner tube gets caught on a swaging portion formed on the outer tube and cannot pass through the swaging portion.

[0024] In contrast, the first embodiment includes a guide member 30 having a fixed portion 31 fixed to the outer periphery of the inner tube 2 (first cylinder), a plurality of extending portions 41 extending in the axial direction of the cylinder from the other end of the fixed portion 31, and R-shaped bulges 43 (second cylinder abutment portions) formed in the center (part) of each extending portion 41 in the longitudinal direction (axial direction of the cylinder) and abutting against the inner circumferential surface 23 of the outer tube 3, and the guide member 30 is made of an elastic material. According to the first embodiment, when the inner tube 2 to which the guide member 30 is attached is assembled (inserted) into the outer tube 3, the extending portions 41 elastically deform inward in the radial direction of the cylinder, thereby reducing the diameter of the guide member 30, allowing the guide member 30 to pass through the swaging portion 25 (recess) formed in the outer tube 3. Furthermore, in the first embodiment, the guide member 30 has an R portion 45 (first cylinder abutment portion) formed at the end on the other end side of each extension portion 41 abutting against the outer peripheral surface 22 of the inner tube 2, and the end 46 (extension direction end) of the R portion 45 is spaced apart from the inner tube 2 and the outer tube 3. Therefore, for example, when the inner tube 2 is pulled out from the outer tube 3 during disassembly of the shock absorber 1, it is possible to avoid a situation in which surrounding parts (such as the inner peripheral surface 23 of the outer tube 3) are damaged by the guide member 30.

[0025] The first embodiment is not limited to the above-described configuration, and can be configured, for example, as follows. In the above-described configuration, a plurality of rectangular claws are formed at equal intervals in the circumferential direction on the other end of a single steel pipe, and a bulge 43 (second cylinder abutment portion) that bulges outward in the radial direction of the cylinder (steel pipe) is formed in the longitudinal center (part) of each claw, thereby forming a guide member 30 having a plurality of extending portions 41. Alternatively, the plurality of extending portions 41 may be formed separately from the fixed portion 31, and one end of each extending portion 41 may be joined to the fixed portion 31 by resistance welding (e.g., "projection welding") to form a guide member 30 having a plurality of extending portions 41. In this case, forming the extending portions 41 is easier than forming the claws integral with the fixed portion 31. In the above-described embodiment, one end of the fixing portion 31 of the guide member 30 (the "protrusion 35" in the first embodiment) is attached to the opening at one end of the inner tube 2 (first cylinder) and abuts against the base valve 10. In contrast, the guide member 30 may be located at any position between the end of the outer tube 3 (second cylinder) opposite to the side where the other end (second end) of the piston rod 6 extends outward and the swaging portion 25 (recess).

[0026] Second Embodiment Next, a second embodiment will be described with reference to Figures 6 and 7. Note that the same names and reference numerals are used for parts common to the first embodiment, and redundant description will be omitted. In the first embodiment, the plurality of extension portions 41 of the guide member 30 extend in the axial direction (the "upward direction" in Figure 4) from the cylindrical fixed portion 31.

[0027] In contrast, in the second embodiment, the guide member 30A has a plurality of (five in the second embodiment) extending portions 41A that extend radially outward from the cylindrical fixed portion 31A. The extending portions 41A are arranged at equal intervals around the circumferential direction of the fixed portion 31A, and are formed by cutting and raising one end of the fixed portion 31A (steel pipe) (the lower end in FIG. 7 ) outward in the radial direction of the cylinder to a constant height H (see FIG. 7 ), forming each of the extending portions into an involute curve shape that is formed when the thread that has been wound around the fixed portion 31A (base circle) in a clockwise direction in a plan view (see FIG. 6 ) is unwound.

[0028] When the inner tube 2 (first cylinder) is inserted into the outer tube 3 (second cylinder) (see FIGS. 6 and 7), an R portion 43A (second cylinder abutting portion) formed at the radially outer end of the extension portion 41A abuts against the inner circumferential surface 23 of the outer tube 3. Furthermore, when the inner tube 2 is inserted into the outer tube 3 (second cylinder), an end 46A (extending direction end) of the radially outer end of the extension portion 41A is spaced apart from the inner tube 2 and the outer tube 3.

[0029] Next, the operation of the guide member 30A in the second embodiment will be described. First, the fixing portion 31A of the guide member 30A is press-fitted onto the outer periphery of the inner tube 2 (first cylinder) from the other end side (the "upper side" in FIG. 7) of the inner tube 2. Note that a base valve 10 is attached to the opening on one end side of the inner tube 2, but in FIG. 7, the base valve 10 is omitted and only the inner tube 2, outer tube 3, and guide member 30A are shown.

[0030] Then, the end of one end of the inner tube 2 (the side to which the base valve 10 is fixed) to which the guide member 30A is fixed is inserted into the outer tube 3 through the opening at the other end (the "upper side" in FIG. 7) of the outer tube 3 (second cylinder). At this time, as the guide member 30A passes through the opening at the other end of the outer tube 3, the R portions 43A (second cylinder abutment portions) of each extension portion 41A of the guide member 30A are pushed radially inward of the cylinder by the inner circumferential surface 23 of the outer tube 3 (the guide member 30A is reduced in diameter), causing the guide member 30A to elastically deform.

[0031] Furthermore, when the guide member 30A passes through the swaging portion 25 of the outer tube 3, i.e., when the rounded portions 43A of each extension portion 41A of the guide member 30A move (slide) along the inner circumferential surface 26 of the swaging portion 25, the rounded portions 43A of each extension portion 41A are elastically deformed as they are pushed radially inward by the swaging portion 25. In other words, the guide member 30A is constrained by the swaging portion 25, reducing the diameter of each extension portion 41A. Note that by rotating the inner tube 2 relative to the outer tube 3 in the clockwise direction in FIG. 6, it is possible to reduce the sliding resistance between each extension portion 41A of the guide member 30A and the outer tube 3.

[0032] When each extension portion 41A of the guide member 30A passes through the swaging portion 25 of the outer tube 3, it is released from the constraint of the swaging portion 25 (the force pressing radially inward of the cylinder) and deforms radially outward of the cylinder due to its own elastic force, causing the R portion 43A to abut (be pressed against) the inner circumferential surface 23 of the outer tube 3. This makes it possible to center one end side (the "lower side" in FIG. 1 ) of the inner tube 2 with respect to the outer tube 3, and allows the base valve 10 attached to one end side of the inner tube 2 to be seated in a fixed position (center) on the bottom portion 20 of the outer tube 3.

[0033] According to the second embodiment, the same effects as those of the first embodiment can be obtained. In the second embodiment, the guide member 30A having the plurality of extending portions 41A is formed by cutting and raising one end of the fixed portion 31A (steel pipe) radially outward of the cylinder to form the plurality of claws, and each claw is formed into an involute curve shape. However, the guide member 30A having the plurality of extending portions 41A may be formed separately from the fixed portion 31A and the radially inner end of each extending portion 41A may be joined to the fixed portion 31A by resistance welding (e.g., "projection welding"). In this case, forming the extending portions 41A is easier than forming the claws integral with the fixed portion 31A.

[0034] Third Embodiment Next, a third embodiment will be described with reference to Figures 8 and 9. The same names and symbols are used for parts common to the above-described embodiments, and duplicated descriptions will be omitted. In the first and second embodiments, carbon steel pipe for machine structural use (STKM) was used as the material for the guide members 30 and 30A.

[0035] In contrast, in the third embodiment, the guide member 30B is made of an elastic synthetic rubber such as NBR (nitrile rubber). The guide member 30B has a cylindrical fixed portion 31B that is fixed by being press-fitted onto the outer periphery of the inner tube 2 (first cylinder), and a plurality of (twelve in the third embodiment) blade-shaped extending portions 41B that protrude radially outward from the cylindrical fixed portion 31B and extend axially. The extending portions 41B have C-chamfered inclined portions 48, 48 formed at both ends (corners) of the cylindrical fixed portion 31B in the axial direction (the "up-down direction" in FIG. 9 ).

[0036] For convenience, in Fig. 9, the guide member 30B is located at a central position in the axial direction of the inner tube 2 (the "vertical direction" in Fig. 9), but in the state of the shock absorber 1 (see Fig. 1), one end side (the "lower side" in Fig. 9) of the fixed portion 31B of the guide member 30B abuts against the base valve 10 (see Fig. 1). In Fig. 9, the base valve 10 is omitted, and only the inner tube 2, outer tube 3, and guide member 30B are shown. Furthermore, Fig. 9 shows the guide member 30B in a cross section taken along line B-B in Fig. 8.

[0037] Next, the operation of the guide member 30B in the third embodiment will be described. First, the fixed portion 31B of the guide member 30B is press-fit onto the outer periphery of the inner tube 2 (first cylinder) from the other end side of the inner tube 2 (the "upper side" in FIG. 9 ). Then, the end of the inner tube 2 to which the guide member 30B is fixed is inserted into the outer tube 3 (second cylinder) through an opening at the other end side of the outer tube 3. During this process, as the guide member 30B passes through the opening at the other end side of the outer tube 3, the radially outer end portions 43B (second cylinder abutment portions) of each extension portion 41B of the guide member 30B are pushed radially inward of the cylinder by the inner circumferential surface 23 of the outer tube 3 (the guide member 30B is reduced in diameter), causing the guide member 30B to elastically deform.

[0038] Furthermore, when the guide member 30B passes through the swaging portion 25 of the outer tube 3, i.e., when the radially outer end portions 43B of each extension portion 41B of the guide member 30B move (slide) along the inner circumferential surface 26 of the swaging portion 25, the radially outer end portions 43B of each extension portion 41B are elastically deformed as they are pushed radially inward by the swaging portion 25. In other words, the guide member 30B is constrained by the swaging portion 25, causing the extension portions 41B to contract in diameter. Note that by rotating the inner tube 2 relative to the outer tube 3 in a clockwise or counterclockwise direction in FIG. 8 , it is possible to reduce the sliding resistance between each extension portion 41B of the guide member 30B and the outer tube 3.

[0039] When each extension portion 41B of the guide member 30B passes through the swaging portion 25 of the outer tube 3, it is released from the constraint of the swaging portion 25 (the force pressing radially inward of the cylinder) and deforms radially outward of the cylinder due to its own elastic force, causing the radially outer end portion 43B to abut (be pressed against) the inner circumferential surface 23 of the outer tube 3. This makes it possible to center one end side (the "lower side" in FIG. 1 ) of the inner tube 2 with respect to the outer tube 3, and allows the base valve 10 attached to one end side of the inner tube 2 to be seated in a fixed position (center) on the bottom portion 20 of the outer tube 3.

[0040] According to the third embodiment, it is possible to obtain the same effects as those of the first embodiment. Furthermore, in the first and second embodiments, a process of molding the plurality of extension portions 41 and 41A of the guide members 30 and 30A using a press or the like is required, which makes the manufacturing process complicated. However, in the third embodiment, the fixed portion 31B and the extension portion 41B of the guide member 30B can be integrally molded, which makes it possible to streamline the manufacturing process.

[0041] Fourth Embodiment Next, a fourth embodiment will be described with reference to FIG. 10 . The same names and symbols are used for parts common to the above-described embodiments, and duplicated descriptions will be omitted. In the first and second embodiments, carbon steel pipe for machine construction (STKM) was used as the material for the guide members 30 and 30A. In the third embodiment, a synthetic rubber having elasticity, such as NBR (nitrile rubber), was used as the material for the guide member 30B.

[0042] In contrast, in the fourth embodiment, a non-linear (barrel-shaped in the fourth embodiment) coil spring is used as the guide member 30C. The guide member 30C has a fixed portion 31C formed at an end (end turn portion on the one end) on one end side (the lower side in FIG. 10 ) and fixed by being press-fitted onto the outer periphery of the inner tube 2 (first cylinder), and an extending portion 41C extending spirally from the fixed portion 31C toward the other end side (the upper side in FIG. 10 ).

[0043] The guide member 30C has a large diameter portion 43C (second cylinder abutment portion) formed at an axially intermediate position (the "up-and-down direction" in FIG. 10) of the extending portion 41C and abutting against the outer tube 3 (second cylinder), and an abutment portion 45C (first cylinder abutment portion) formed at an end (seat winding portion on the other end side) on the other end side (the "upper side" in FIG. 10) of the fixed portion 31C and abutting against the outer peripheral surface 22 of the inner tube 2. It is desirable to set the outer diameter of each effective winding portion of the extending portion 41 smaller than the inner diameter d of the swaging portion 25, except for the effective winding portion where the large diameter portion 43C is formed.

[0044] For convenience, in Fig. 10, the guide member 30C is located at a central position in the axial direction of the inner tube 2 (the "vertical direction" in Fig. 10), but in the state of the shock absorber 1 (see Fig. 1), one end side (the "lower side" in Fig. 10) of the fixing portion 31C of the guide member 30C abuts against the base valve 10 (see Fig. 1). In Fig. 10, the base valve 10 is omitted and only the inner tube 2, outer tube 3, and guide member 30C are shown.

[0045] Next, the operation of the guide member 30C in the fourth embodiment will be described. First, the fixing portion 31C of the guide member 30C is press-fitted onto the outer periphery of the inner tube 2 (first cylinder) from the other end side of the inner tube 2 (the "upper side" in FIG. 10 ). Then, the end of the inner tube 2 to which the guide member 30C is fixed is inserted into the outer tube 3 (second cylinder) through an opening on the other end side of the outer tube 3. At this time, as the guide member 30C passes through the opening on the other end side of the outer tube 3, the large diameter portion 43C (second cylinder abutment portion) of the guide member 30C is pushed radially inward of the cylinder by the inner circumferential surface 23 of the outer tube 3 (the coil spring is compressed), causing the guide member 30C to elastically deform.

[0046] Furthermore, when the guide member 30C passes through the swaging portion 25 of the outer tube 3, i.e., when the large diameter portion 43C of the extending portion 41C of the guide member 30C moves (slides) along the inner circumferential surface 26 of the swaging portion 25, the large diameter portion 43C of the extending portion 41C of the guide member 30C is elastically deformed as it is pushed radially inward of the cylinder by the swaging portion 25. In other words, the extending portion 41C of the guide member 30C is constrained by the swaging portion 25, thereby reducing its diameter. Note that by rotating the inner tube 2 around the axis (clockwise or counterclockwise) relative to the outer tube 3, it is possible to reduce the sliding resistance between the large diameter portion 43C of the extending portion 41C of the guide member 30C and the outer tube 3.

[0047] When the large diameter portion 43C of the extension portion 41C of the guide member 30C passes through the swaging portion 25 of the outer tube 3, it is released from the constraint of the swaging portion 25 (the force pressing radially inward of the cylinder) and is deformed radially outward of the cylinder by the elastic force of the spring, causing the large diameter portion 43C of the extension portion 41C to abut (be pressed against) the inner circumferential surface 23 of the outer tube 3. This makes it possible to center one end side (the "lower side" in FIG. 1 ) of the inner tube 2 with respect to the outer tube 3, and allows the base valve 10 attached to one end side of the inner tube 2 to be seated in a fixed position (center) on the bottom portion 20 of the outer tube 3.

[0048] According to the fourth embodiment, it is possible to obtain the same effects as those of the first embodiment. Furthermore, in the fourth embodiment, a coil spring is used as the guide member 30C, which reduces manufacturing costs.

[0049] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0050] This application claims priority to Japanese Patent Application No. 2024-102247, filed June 25, 2024. The entire disclosure of Japanese Patent Application No. 2024-102247, filed June 25, 2024, including the specification, claims, drawings, and abstract, is incorporated herein by reference in its entirety.

[0051] 1 shock absorber, 2 inner tube (first cylinder), 2A first chamber, 2B second chamber, 3 outer tube (second cylinder), 4 reservoir chamber, 5 piston, 6 piston rod, 25 swaging portion (recess), 30 guide member, 31 fixing portion, 41 extension portion, 43 bulge portion (second cylinder abutment portion)

Claims

1. A shock absorber comprising: a first cylinder in which a working fluid is sealed; a second cylinder provided on the outer periphery of the first cylinder and having a recess, at least a portion of which deforms radially inward; a reservoir chamber formed between the first cylinder and the second cylinder and in which a working fluid and a gas are sealed; a piston slidably inserted into the first cylinder and dividing the interior of the first cylinder into two chambers, a first chamber and a second chamber; a piston rod having a first end connected to the piston and a second end extending to the outside of the first cylinder and the second cylinder; and a guide member having a fixed portion fixed to the outer periphery of the first cylinder, a plurality of extension portions extending from the fixed portion, and a second cylinder abutment portion formed on a part of the extension portion and abutting against the second cylinder, which elastically deforms the extension portions to bias the first cylinder and the second cylinder so as to separate them radially.

2. A shock absorber as claimed in claim 1, wherein the guide member is arranged between the end of the second cylinder opposite the side where the second end of the piston rod extends outward and the recess of the second cylinder.

3. A shock absorber according to claim 1, wherein the extension portion is provided with a first cylinder abutment portion formed on a part of the extension portion and abutting against the first cylinder.

4. A shock absorber according to claim 1, wherein the end of the extension portion in the extension direction is formed so as to be spaced apart from the first cylinder and the second cylinder.

5. A shock absorber according to claim 1, wherein the extension portion extends from the fixed portion radially outward of the first cylinder.

6. A shock absorber according to claim 1, wherein the extension portion is formed in a spiral shape extending from the fixed portion radially outward and axially of the first cylinder.

Images