buffer

Abstract

To provide a buffer capable of preventing deformation of a support without increasing manufacturing cost and weight.SOLUTION: A buffer D includes: a cylinder 1; a piston 2 slidably inserted into the cylinder 1; a piston rod 3 movably inserted into the cylinder 1; a rebound spring 4 having a coil spring 5 disposed on the outer periphery of the piston rod 3 and an annular lower collar 6 fitted to the coil spring 5; and an annular support 8 axially opposing to the lower collar 6 and supporting an end on the piston side of the lower collar. The support 8 includes: a cylindrical part 8a fitted to the outer periphery of the piston rod 3; and an annular receiving part 8b having an inner periphery connected to an end on a side opposite to the piston of the cylindrical part 8a, axially opposing to the end on the piston side of the lower collar 6 and enabling abutment to the lower collar 6. A regulation part for regulating eccentricity of the lower collar 6 to the receiving part 8b is provided.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] In conventional shock absorbers, a rebound spring consisting of a coil spring with resin collars attached to both ends is interposed between a rod guide that seals the cylinder end and supports the piston rod, and a support that is welded to the middle of the piston rod and has a flange-shaped receiving part. When the shock absorber extends, this rebound spring is sandwiched and compressed between the rod guide and the receiving part of the support, which approach each other, and exerts a spring force that suppresses the extension of the shock absorber, absorbing the impact when the shock absorber is fully extended.

[0003] For example, the rebound spring disclosed in Patent Document 1 is configured to include a coil spring and upper and lower collars made of resin that are fitted onto the inner periphery of both ends of the coil spring.

[0004] The lower collar fixes the coil spring to the outer periphery of the piston rod, while the upper collar faces the piston rod with a gap between them, allowing it to move relative to the piston rod. In this way, the coil spring is fixed by the lower collar at the end closest to the piston, but the end opposite the piston is a free end. When the upper collar abuts against the rod guide or the cushion rubber attached to the bottom end of the rod guide, it contracts, exerting a spring force that suppresses the extension of the shock absorber. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-148268 Summary of the Invention [Problem to be solved by the invention]

[0006] As shown in FIG. 7, the support 100 described above is configured to include a cylindrical portion 100a that is welded and fixed to the piston rod 101, and a flange-shaped receiving portion 100b whose inner periphery is continuous with the end of the cylindrical portion 100a on the side opposite to the piston, and the angle formed by the receiving portion 100b and the cylindrical portion 100a is a right angle.

[0007] As described above, when the rebound spring 102 contracts during extension of the shock absorber, it exerts a spring force and presses the lower collar 103 against the receiving portion 100b of the support 100 configured as described above, but if a lateral force acts on the shock absorber and thus on the rod 104, the rebound spring 102 may become eccentric with respect to the support 100. When the rebound spring 102 becomes eccentric with respect to the support 100 in this way, the lower collar 103 also becomes displaced radially with respect to the support 100.

[0008] If the lower collar 103 becomes eccentric relative to the support 100 and shifts radially in this manner, the line of action of the spring force generated by the compression of the rebound spring 102 shifts toward the outer periphery of the receiving portion 100b, causing a large moment to act on the receiving portion 100b. As a result, as shown by the dashed line in Figure 7, the outer periphery of the receiving portion 100b of the support 100 is deformed so as to bend toward the cylindrical portion, which may damage the seat portion 103a of the lower collar 103 that abuts against the support 100 and the fitting portion 103b that fits with the rebound spring 102. To prevent such deformation of the support 100, it is necessary to increase the thickness of the support 100, but doing so increases the manufacturing cost and weight of the shock absorber.

[0009] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a shock absorber that can prevent deformation of the support without increasing manufacturing costs and weight. [Means for solving the problem]

[0010] In order to achieve the above object, the shock absorber of the present invention comprises a cylinder and aInside Da a piston rod movably inserted into the cylinder and one end connected to the piston; a rebound spring having a coil spring disposed on the outer periphery of the piston rod and an annular lower collar attached to the piston-side end of the coil spring and fitted onto the outer periphery of the piston rod; an annular support attached to the outer periphery of the piston rod and axially facing the lower collar to support the piston-side end of the lower collar, the support comprising a cylindrical part attached to the outer periphery of the piston rod; and an annular receiving part whose inner periphery is connected to the end of the cylindrical part opposite the piston-side end of the lower collar in the axial direction and can abut against the lower collar, and a restricting part is provided to restrict eccentricity of the lower collar relative to the receiving part.

[0011] With a shock absorber configured in this manner, the strength can be improved without increasing the thickness of the support, so even if the rebound spring contracts and becomes eccentric relative to the support when the shock absorber is extended, deformation such as bending the outer periphery of the receiving part of the support toward the tubular part due to the spring force received from the rebound spring can be suppressed.

[0012] The restricting portion may be formed by inclining the outer periphery of the receiving portion toward the side away from the piston.

[0013] Furthermore, the restricting portion is a receiving portion. of Outer periphery of lower collar Only In a shock absorber configured in this manner, fatigue of the lower collar can be reduced even when the lower collar is subjected to repeated spring force from the coil spring.

[0014] Furthermore, the regulating part is the receiving part. of Inner circumference of the lower collar Only The shock absorber configured in this manner can enhance the effect of suppressing deformation of the receiving portion.

[0015] The angle between the receiving part and the cylindrical part in the cross section of the support ofThe restricting portion may be formed by setting the angle to be greater than 90 degrees.

[0016] The restricting portion is formed by making the angle formed by the receiving portion and the cylindrical portion in the cross section of the support larger than 90 degrees and by making the piston side end surface of the lower collar an inclined surface. , Pi The angle of inclination at the end face of the stone is the angle formed by the cylindrical part and the receiving part in the cross section of the support. degree The angle may be smaller than the angle obtained by subtracting 90 degrees from the angle of the coil spring. With a shock absorber configured in this manner, fatigue of the lower collar can be reduced even when the shock absorber is subjected to repeated spring force from the coil spring.

[0017] The restricting portion may be formed by making the angle between the receiving portion and the cylindrical portion in the cross section of the support larger than 90 degrees and making the piston side end surface of the lower collar an inclined surface, so that the inclination angle of the piston side end surface is larger than the angle between the cylindrical portion and the receiving portion in the cross section of the support minus 90 degrees. Great deal do. The restricting portion may be formed by folding back the outer periphery of the receiving portion in a cross section of the support, with the outer periphery facing the outer periphery of the lower collar, with the angle between the outer periphery and the cylindrical portion set to be 180 degrees or more. The lower collar may have three or more ridges on its inner periphery that abut against the outer periphery of the piston rod. [Effects of the Invention]

[0018] According to the shock absorber of the present invention, deformation of the support can be prevented without increasing manufacturing costs and weight. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a longitudinal sectional view of a shock absorber according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged vertical cross-sectional view of a support portion of the shock absorber according to the embodiment of the present invention. [Figure 3] FIG. 2 is an enlarged vertical cross-sectional view of a rebound spring of the shock absorber according to the embodiment of the present invention. [Figure 4] FIG. 4 is an enlarged vertical cross-sectional view of a support portion of a shock absorber according to a first modified example of the embodiment of the present invention. [Figure 5]FIG. 10 is an enlarged vertical cross-sectional view of a support portion of a shock absorber according to a second modified example of the embodiment of the present invention. [Figure 6] 1(a) is an enlarged vertical cross-sectional view of a support portion of a shock absorber according to a third modified example of an embodiment of the present invention, and FIG. 1(b) is an enlarged vertical cross-sectional view of a support portion of a shock absorber according to a fourth modified example of an embodiment of the present invention. [Figure 7] FIG. 10 is an enlarged vertical cross-sectional view of a conventional support. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a shock absorber D in one embodiment comprises a cylinder 1, a piston 2 slidably inserted into the cylinder 1, and a piston movably inserted into the cylinder 1 and having one end Gapi Ston 2 the piston rod 3 connected to the piston rod 3, the rebound spring 4 having a coil spring 5 and a lower collar 6 attached to the piston side end 5a of the coil spring 5, and an annular support 8 axially facing the lower collar 6 and supporting the piston side end of the lower collar 6.

[0021] Each part will be described in detail below. The cylinder 1 is cylindrical and has a bottom, and an annular rod guide 9 is attached to the upper end in FIG. 1. The rod guide 9 seals the upper end opening of the cylinder 1, and the piston rod 3 is inserted through its inner periphery, supporting the piston rod 3 so that it can slide freely. A seal member 10 that slides against the outer periphery of the piston rod 3 is fixed to the cylinder 1 in an overlapping state at the upper part in FIG. 1, which is the atmospheric side of the rod guide 9, and seals the outer periphery of the piston rod 3. The seal member 10 also seals between the cylinder 1 and the outer periphery of the rod guide 9, and the inside of the cylinder 1 is liquid-tightly sealed.

[0022] The inside of the cylinder 1 is divided by the piston 2 inserted into the cylinder 1 into an extension-side chamber R1 above the piston 2 in Fig. 1 and a compression-side chamber R2 below the piston 2 in Fig. 1, and the extension-side chamber R1 and the compression-side chamber R2 are filled with a liquid such as hydraulic oil. In addition, in the case of this shock absorber D, a free piston 11 is slidably inserted below the piston 2 in the cylinder 1, and an air chamber G filled with gas is formed below the free piston 11 in the cylinder 1.

[0023] The piston 2 is provided with a passage 2a that connects the expansion-side chamber R1 and the compression-side chamber R2, and a damping valve 2b that serves as a damping force generating element and is provided in the middle of the passage 2a. When the shock absorber D extends and the expansion-side chamber R1 is compressed by the piston 2, the liquid in the expansion-side chamber R1 passes through the passage 2a and moves to the compression-side chamber R2. The damping valve 2b then applies resistance to the flow of the liquid, causing the pressure in the expansion-side chamber R1 to rise, resulting in a difference in pressure between the expansion-side chamber R1 and the compression-side chamber R2. When the shock absorber D contracts, the piston 2 compresses the compression-side chamber R2, causing the liquid in the compression-side chamber R2 to pass through the passage 2a and move to the expansion-side chamber R1. The damping valve 2b then applies resistance to the flow of the liquid, causing the pressure in the compression-side chamber R2 to rise, resulting in a difference in pressure between the compression-side chamber R2 and the expansion-side chamber R1. but arise.

[0024] In this way, when the shock absorber D is extended, the pressure in the expansion-side chamber R1 becomes higher than the pressure in the compression-side chamber R2, and the differential pressure between the pressure in the expansion-side chamber R1 and the pressure in the compression-side chamber R2 acts on the piston 2, and the shock absorber D moves the piston 2 upward in FIG. of Outputs damping force to prevent do On the other hand, when the shock absorber D contracts, the pressure in the compression-side chamber R2 becomes higher than the pressure in the expansion-side chamber R1, and the pressure difference between the pressure in the compression-side chamber R2 and the pressure in the expansion-side chamber R1 acts on the piston 2, causing the shock absorber D to output a damping force that prevents the piston 2 from moving downward in FIG.

[0025] In the case of this shock absorber D, when the expansion / contraction operation is performed, the piston rod 3 moves in and out of the cylinder 1, so that the piston rod 3 is pushed aside in the cylinder 1. volume changes. volumeThe change occurs when the free piston 11 moves up and down in the cylinder 1 and the air chamber G volume In this way, shock absorber D is a so-called single-rod single-tube shock absorber, but an outer cylinder or tank is provided outside the cylinder 1, and a reservoir filled with gas and liquid is formed between the outer cylinder and the cylinder 1 or in the tank, and the reservoir compensates for the change in the displacement volume of the piston rod 3. Complex The shock absorber D may be a cylindrical shock absorber. Alternatively, the shock absorber D may be a double rod type shock absorber in which the piston rod 3 is inserted through both the extension-side chamber R1 and the compression-side chamber R2.

[0026] In this case, the damping valve 2b provided in the piston 2 is a throttle that allows both the flow of fluid from the extension-side chamber R1 to the compression-side chamber R2 and the flow of fluid from the compression-side chamber R2 to the extension-side chamber R1, but a plurality of passages 2a may be provided, some of which may be provided with damping valves that allow only the flow of fluid from the extension-side chamber R1 to the compression-side chamber R2, and the remaining passages may be provided with damping valves that allow only the flow of fluid from the compression-side chamber R2 to the extension-side chamber R1. Furthermore, the passage 2a and the damping valve 2b may be provided in a location other than the piston 2, for example, in the piston rod 3 or outside the cylinder 1.

[0027] The piston rod 3 has the piston 2 attached to its tip, which is the lower end in Fig. 1, and its upper end in Fig. 1 protrudes outside the cylinder 1 through the inner periphery of a rod guide 9. In addition, a support 8 is fixed by welding to the outer periphery of the piston rod 3 at the lower part in Fig. 1.

[0028] As shown in FIGS. 1 and 2 , the support 8 includes a cylindrical portion 8a attached to the outer periphery of the piston rod 3 and a ring-shaped receiving portion 8b whose inner periphery is connected to the end of the cylindrical portion 8a opposite the piston. The support 8 is formed by expanding the diameter of a pipe material at the middle portion in the axial direction. The angle θ between the receiving portion 8b and the cylindrical portion 8a in the cross section of the support 8 is greater than 90 degrees and is 110 degrees. The receiving portion 8b is inclined so as to gradually move away from the piston rod 3 toward the outer periphery, and has a tapered inclined surface 8b1 on the opposite side to the piston. The support 8 configured in this manner is fixed to the piston rod 3 by inserting the piston rod 3 into the cylindrical portion 8a, fitting the cylindrical portion 8a into a predetermined position on the outer periphery of the piston rod 3, and then attaching the cylindrical portion 8a to the outer periphery of the piston rod 3 by projection welding. In the shock absorber D of this embodiment, the angle θ between the receiving portion 8b and the cylindrical portion 8a in the cross section of the support 8 is 110 degrees. of By making the angle greater than 90 degrees, a restricting portion is formed that restricts eccentricity of the lower collar 6 relative to the receiving portion 8b of the support 8. When the restricting portion is formed by making the angle θ formed by the receiving portion 8b and the tubular portion 8a greater than 90 degrees, the angle θ may be any angle greater than 90 degrees, but from the viewpoint of supporting the lower collar 6, it is preferable that the angle obtained by subtracting 90 degrees from the angle θ be set in the range of 10 degrees to 35 degrees.

[0029] As described above, the rebound spring 4 is composed of the coil spring 5, into which the piston rod 3 is inserted and which is arranged on the outer periphery of the piston rod 3; the annular lower collar 6, which is attached to the piston side end 5a, which is the lower end of the coil spring 5 in FIG. 1, and which is fitted onto the outer periphery of the piston rod 3; and the annular upper collar 7, which is attached to the anti-piston side end, which is the upper end of the coil spring 5 in FIG. 1, and which is arranged on the outer periphery of the piston rod 3.

[0030] As shown in FIGS. 1 and 3, the coil spring 5 has an end turn portion at the piston side end 5a at the lower end, and an end turn portion at the opposite piston side end 5b at the upper end in FIGS.

[0031] In this case, the lower collar 6 is made of a hard resin material and, as shown in Fig. 3, is configured to include an annular seat portion 6a, a cylindrical fitting portion 6b that rises from the inner periphery of the coil spring side end of the seat portion 6a and has an outer diameter smaller than that of the seat portion 6a, and a plurality of protrusions 6c provided on the inner periphery of the seat portion 6a. The lower collar 6 configured in this manner is attached to the coil spring 5 by press-fitting the fitting portion 6b into the inner periphery of the piston side end 5a of the coil spring 5. The tip of the fitting portion 6b of the lower collar 6 has a tapered outer diameter, which allows the fitting portion 6b to be smoothly inserted into the piston side end 5a of the coil spring 5, making the attachment of the lower collar 6 to the coil spring 5 easy.

[0032] The lower end surface of the seat portion 6a in Figure 2, which is the piston-side end surface 6d of the lower collar 6, is an inclined surface that gradually moves away from the piston 2 as it moves toward the outer periphery, and the inclination angle α of the inclined surface in the shock absorber D of this embodiment is an angle smaller than 20 degrees, which is the angle θ formed by the tubular portion 8a and the receiving portion 8b in the cross section of the support 8 minus 90 degrees.

[0033] In this embodiment, three ridges 6c are provided at equal intervals around the inner periphery of the lower collar 6, and they apply tension to the outer periphery of the piston rod 3 inserted into the inner periphery to fix the lower collar 6 to the outer periphery of the piston rod 3. The number of ridges 6c provided can be any number as long as it is three or more. In addition, the lower collar 6 has an inclined piston-side end surface 6d that abuts against the receiving portion 8b of the support 8, thereby restricting the downward movement of the rebound spring 4 relative to the piston rod 3 in FIG.

[0034] The inclination angle α of the piston side end face 6d of the lower collar 6 is smaller than 20 degrees, which is the angle θ formed by the cylindrical portion 8a and the receiving portion 8b in the cross section of the support 8 minus 90 degrees. Therefore, when no load is applied, the outer periphery of the piston side end face 6d of the lower collar 6 is in line contact with the receiving portion 8b of the support 8.

[0035] In this case, the upper collar 7 is made of a hard fiber-reinforced resin, and as shown in FIG. 3, it has an annular seat portion 7a and a coil spring-side end of the seat portion 7a. hand It is configured with a cylindrical fitting portion 7b whose rising outer diameter is smaller than that of the seat portion 7a, and a plurality of annular protrusions 7c provided on the inner periphery of the seat portion 7a and facing inward.

[0036] The upper collar 7 configured in this manner is attached to the coil spring 5 by press-fitting the fitting portion 7b onto the inner periphery of the end turn at the anti-piston end 5b of the coil spring 5. The outer diameter of the tip of the fitting portion 7b of the upper collar 7 is tapered, which allows the fitting portion 7b to be smoothly inserted into the anti-piston end 5b of the coil spring 5, making it easy to attach the upper collar 7 to the coil spring 5.

[0037] In the shock absorber D configured as described above, when the piston 2 moves upward in FIG. 1 during an extension operation, the upper collar 7 comes into contact with the rod guide 9 and the coil spring 5 is compressed, causing the coil spring 5 to generate a spring force that prevents the piston 2 from moving upward in FIG. 1. Furthermore, during an extension operation, the shock absorber D generates a difference between the pressure in the extension-side chamber R1 and the pressure in the compression-side chamber R2, as described above, to generate a damping force that prevents the piston 2 from moving upward in FIG. 1. Therefore, in a situation where the rebound spring 4 is compressed during an extension operation of the shock absorber D, the force exerted by the shock absorber D is the sum of the spring force that prevents the movement of the piston 2, generated by the rebound spring 4, and the damping force that prevents the movement of the piston 2 due to the pressure difference.

[0038] In this way, when the shock absorber D is extended and the upper collar 7 abuts against the rod guide 9, the coil spring 5 contracts and generates a spring force, and the lower collar 6 is pressed against the receiving portion 8b of the support 8 by this spring force.

[0039] Because the angle θ between the cylindrical portion 8a and the receiving portion 8b in the cross section of the support 8 is greater than 90 degrees, internal stress in the support 8, which is formed by bending a pipe material midway, is reduced, improving the durability of the support 8. Furthermore, because the angle θ between the cylindrical portion 8a and the receiving portion 8b in the cross section of the support 8 is greater than 90 degrees and the receiving portion 8b has a disc spring shape, the strength of the support 8 against a load that expands the diameter of the receiving portion 8b toward the cylindrical portion 8a is significantly higher than when the angle θ is 90 degrees. Therefore, the durability and strength of the support 8 are improved without increasing the thickness of the support 8, and deformation in which the diameter of the receiving portion 8b expands when subjected to the spring force of the coil spring 5 is suppressed, preventing deformation in which the outer periphery of the receiving portion 8b bends toward the cylindrical portion 8a, as in the conventional support 100.

[0040] As described above, the shock absorber D of this embodiment comprises the cylinder 1, the piston 2 slidably inserted into the cylinder 1, the piston rod 3 movably inserted into the cylinder 1 and one end of which is connected to the piston 2, the rebound spring 4 having the coil spring 5 disposed on the outer periphery of the piston rod 3 and the annular lower collar 6 attached to the piston side end 5a of the coil spring 5 and fitted to the outer periphery of the piston rod 3, and the lower collar 6 attached to the outer periphery of the piston rod 3 and facing the lower collar 6 in the axial direction. 6 The support 8 has a cylindrical portion 8a attached to the outer periphery of the piston rod 3, and a receiving portion 8b which is annular and has an inner periphery connected to the end of the cylindrical portion 8a opposite the piston side end of the lower collar 6 in the axial direction and can abut against the lower collar 6, and a restricting portion is provided which restricts eccentricity of the lower collar 6 relative to the receiving portion 8b.

[0041] According to the shock absorber D configured in this manner, the eccentricity of the lower collar 6 relative to the support 8 is restricted by the restricting portion, so that the lower collar 6 does not shift in the radial direction, and it is therefore possible to prevent a large moment from acting on the receiving portion 8b when the rebound spring 4 is compressed. Therefore, according to the shock absorber D configured in this manner, it is possible to suppress deformation, such as bending the outer periphery of the receiving portion 8b toward the tubular portion 8a, due to the spring force received from the rebound spring 4 when the shock absorber D is extended, without increasing the thickness of the support 8. As described above, according to the shock absorber D of this embodiment, it is possible to improve the durability and strength of the support 8 and suppress bending deformation without increasing the thickness of the support 8, so it is possible to prevent deformation of the support 8 without incurring increases in manufacturing cost and weight.

[0042] Furthermore, in shock absorber D of this embodiment, a restricting portion is formed by making the angle formed by receiving portion 8b and cylindrical portion 8a in the cross section of support 8 greater than 90 degrees. According to shock absorber D configured in this manner, by making the angle formed by receiving portion 8b and cylindrical portion 8a in the cross section of support 8 greater than 90 degrees, the strength of support 8 can be improved and a restricting portion can be formed that restricts eccentricity of lower collar 6 with respect to receiving portion 8b, thereby reducing manufacturing costs.

[0043] When the lower collar 6 is supported by the conventional support 100, the fitting portion 6b fits onto the inner periphery of the end turn portion of the piston-side end 5a of the coil spring 5, and a tension force in the radial contraction direction is always applied to the fitting portion 6b, and when it receives the spring force of the rebound spring 4, the receiving portion 100b of the support 100 also bends and deforms, and a moment acts on the outer periphery of the seat portion 6a of the lower collar 6 toward the piston 2 relative to the inner periphery. Therefore, with the structure of the conventional support 100, a large tensile force acts between the fitting portion 6b, which receives a tension force in the radial contraction direction from the coil spring 5, and the seat portion 6a, which receives a moment due to the spring force generated by the compression of the coil spring 5, causing fatigue in the lower collar 6. However, in the shock absorber D of this embodiment, the angle θ formed by the receiving portion 8b and the cylindrical portion 8a in the cross section of the support 8 is set to be larger than 90 degrees, and the piston-side end face 6d of the lower collar 6 is formed as an inclined surface to form a restricting portion, so that the inclination angle α of the piston-side end face 6d is smaller than the angle obtained by subtracting 90 degrees from the angle θ formed by the cylindrical portion 8a and the receiving portion 8b in the cross section of the support 8. Therefore, the outer periphery of the piston-side end face 6d of the lower collar 6 abuts against the receiving portion 8b of the support 8. In the shock absorber D configured in this manner, when an axial load is applied from the rebound spring 4 to the seat portion 6a of the lower collar 6, the lower collar 6 receives a moment that moves the inner periphery of the seat portion 6a toward the receiving portion 8b. Therefore, the tensile force acting between the fitting portion 6b and the seat portion 6a due to the tension force that the fitting portion 6b receives from the coil spring 5 can be alleviated by this moment. Therefore, according to the shock absorber D configured in this manner, fatigue of the lower collar 6 can be reduced even when the shock absorber D is subjected to repeated spring force from the coil spring 5. In the illustrated example, the piston side end surface 6d of the lower collar 6 is made into a tapered surface to form an inclined surface, but even in this case, as long as the outer periphery of the piston side end 6d of the lower collar 6 can be set to abut against the receiving portion 8b of the support 8, the inclined surface may be a curved surface other than a tapered surface.

[0044] 4, when the angle θ formed by the receiving portion 8b and the cylindrical portion 8a in the cross section of the support 8 is made larger than 90 degrees, and the piston-side end surface 6d of the lower collar 6 is made an inclined surface to form a restricting portion, and the inclination angle α of the piston-side end surface 6d is made larger than the angle obtained by subtracting 90 degrees from the angle θ formed by the cylindrical portion 8a and the receiving portion 8b in the cross section of the support 8, the inner periphery of the piston-side end surface 6d of the lower collar 6 comes into contact with the receiving portion 8b of the support 8. In the shock absorber D configured in this manner, the spring force generated by the compression of the coil spring 5 is transmitted to the receiving portion 8b of the support 8 through the inner periphery of the lower collar 6, so that the line of action of the load received from the rebound spring 4 passes through the thickness of the cylindrical portion 8a of the support 8 or near the outer periphery of the cylindrical portion 8a, and the moment bending the outer periphery of the receiving portion 8b toward the cylindrical portion 8a can be greatly reduced, thereby improving the effect of suppressing deformation of the receiving portion 8b.

[0045] Furthermore, if the angle θ formed by the receiving portion 8b and the cylindrical portion 8a in the cross section of the support 8 is made larger than 90 degrees, and a restricting portion is formed by making the piston-side end surface 6d of the lower collar 6 an inclined surface, and the inclination angle α of the piston-side end surface 6d is made equal to the angle obtained by subtracting 90 degrees from the angle θ formed by the cylindrical portion 8a and the receiving portion 8b in the cross section of the support 8, fatigue of the lower collar 6 can be reduced even when it is subjected to repeated spring force from the coil spring 5, and the deformation suppression effect of the receiving portion 8b can be improved. However, to make the inclination angle α equal to the angle obtained by subtracting 90 degrees from the angle θ in this way, dimensional control of the lower collar 6 and the support 8 must be strict. Therefore, when considering the mass productivity of the lower collar 6 and the support 8, if you want to reduce fatigue in the lower collar 6, it is better to make the inclination angle α smaller than the angle obtained by subtracting 90 degrees from the angle θ than to make the inclination angle α equal to the angle obtained by subtracting 90 degrees from the angle θ, in that this makes manufacturing easier; and if you want to increase the deformation suppression effect of the receiving portion 8b, it is better to make the inclination angle α larger than the angle obtained by subtracting 90 degrees from the angle θ than to make the inclination angle α equal to the angle obtained by subtracting 90 degrees from the angle θ, in that this makes manufacturing easier.

[0046] In the above description, the piston-side end surface 6d of the lower collar 6 is an inclined surface. However, as shown in FIG. 5, the piston-side end surface 6d may be stepped so that the outer diameter of the seat portion 6a increases in stages. When the piston-side end surface 6d is stepped in this manner, an imaginary plane V passing through the edge of the step becomes an inclined surface. Therefore, if the inclination angle of the imaginary plane V is smaller than the angle θ formed by the cylindrical portion 8a and the receiving portion 8b in the cross section of the support 8 minus 90 degrees, the outer circumferential side of the seat portion 6a abuts against the receiving portion 8b, thereby reducing fatigue of the lower collar 6. Furthermore, if the inclination angle of the imaginary plane V is larger than the angle θ formed by the cylindrical portion 8a and the receiving portion 8b in the cross section of the support 8 minus 90 degrees, the inner circumferential side of the seat portion 6a abuts against the receiving portion 8b, thereby enhancing the effect of suppressing deformation of the receiving portion 8b. In this way, the category of making the piston side end surface 6d of the lower collar 6 an inclined surface also includes making the piston side end surface 6d of the lower collar 6 stepped and making a virtual plane V passing through the edge of the step an inclined surface.

[0047] The piston-side end surface 6d of the seat portion 6a of the lower collar 6 may not be an inclined surface, but may be a flat surface or an inclined surface that is inclined in the opposite direction to the inclined surface shown in Figure 2 or Figure 4.In this case, too, the outer periphery of the piston-side end surface 6d of the lower collar 6 abuts against the receiving portion 8b of the support 8, so that fatigue of the lower collar 6 can be reduced even if it is repeatedly subjected to the spring force of the coil spring 5.

[0048] 6(a), in the cross section of the support 8, only the outer periphery 8b2 of the receiving portion 8b may be inclined so that the angle formed by the outer periphery 8b2 of the receiving portion 8b and the cylindrical portion 8a is greater than 90 degrees, thereby forming a restricting portion that restricts eccentricity of the lower collar 6 relative to the receiving portion 8b. Furthermore, as shown in FIG. 6(b), the outer periphery 8b2 of the receiving portion 8b may be folded back so that the angle formed by the outer periphery 8b3 of the receiving portion 8b and the cylindrical portion 8a is set to 180 degrees or greater, and the outer periphery 8b3 may be opposed to the outer periphery of the seat portion 6a of the lower collar 6, thereby forming a restricting portion that restricts eccentricity of the lower collar 6 relative to the receiving portion 8b.

[0049] Furthermore, a groove or a recess may be provided on the piston-side end surface 6d of the lower collar 6 for the purpose of suppressing hitting noise with the receiving portion 8b.

[0050] Although the preferred embodiment of the present invention has been described in detail, modifications, variations and changes can be made thereto without departing from the scope of the appended claims. [Explanation of symbols]

[0051] 1····cylinder, 2···piston, 3···piston rod, 4···rebound spring, 5···coil spring, 6···lower collar, 6d···piston side end face of lower collar, 8···support, 8a···cylindrical portion, 8b···receiving portion (restricting portion), 8b2, 8b3···outer periphery of receiving portion (restricting portion)

Claims

1. A cylinder; a piston slidably inserted in the cylinder; a piston rod that is movably inserted into the cylinder and has one end connected to the piston; a rebound spring including a coil spring disposed on an outer periphery of the piston rod and an annular lower collar attached to a piston-side end of the coil spring and fitted onto an outer periphery of the piston rod; an annular support attached to an outer periphery of the piston rod and facing the lower collar in the axial direction to support a piston-side end of the lower collar; the support has a cylindrical portion attached to an outer periphery of the piston rod, and an annular receiving portion whose inner periphery is connected to the end of the cylindrical portion opposite the piston side and which faces the piston side end of the lower collar in the axial direction and can abut against the lower collar, a restricting portion that restricts eccentricity of the lower collar relative to the receiving portion; The restricting portion restricts the eccentricity by bringing the receiving portion into contact only with the outer circumferential side of the lower collar. A shock absorber characterized by:

2. A cylinder, a piston slidably inserted in the cylinder; a piston rod that is movably inserted into the cylinder and has one end connected to the piston; a rebound spring including a coil spring disposed on an outer periphery of the piston rod and an annular lower collar attached to a piston-side end of the coil spring and fitted onto an outer periphery of the piston rod; an annular support attached to an outer periphery of the piston rod and facing the lower collar in the axial direction to support a piston-side end of the lower collar; the support has a cylindrical portion attached to an outer periphery of the piston rod, and an annular receiving portion whose inner periphery is connected to the end of the cylindrical portion opposite the piston side and which faces the piston side end of the lower collar in the axial direction and can abut against the lower collar, a restricting portion that restricts eccentricity of the lower collar relative to the receiving portion; The restricting portion restricts the eccentricity by bringing the receiving portion into contact only with the inner circumferential side of the lower collar. A shock absorber characterized by:

3. A cylinder, a piston slidably inserted in the cylinder; a piston rod that is movably inserted into the cylinder and has one end connected to the piston; a rebound spring including a coil spring disposed on an outer periphery of the piston rod and an annular lower collar attached to a piston-side end of the coil spring and fitted onto an outer periphery of the piston rod; an annular support attached to an outer periphery of the piston rod and facing the lower collar in the axial direction to support a piston-side end of the lower collar; the support has a cylindrical portion attached to an outer periphery of the piston rod, and an annular receiving portion whose inner periphery is connected to the end of the cylindrical portion opposite the piston side and which faces the piston side end of the lower collar in the axial direction and can abut against the lower collar, a restricting portion that restricts eccentricity of the lower collar relative to the receiving portion; the restricting portion is formed by making the angle formed by the receiving portion and the cylindrical portion in a cross section of the support greater than 90 degrees, and by making the piston-side end surface of the lower collar an inclined surface that gradually becomes farther away from the piston as it goes toward the outer periphery, The inclination angle of the inclined surface of the lower collar is smaller than the angle in the cross section of the support minus 90 degrees. A shock absorber characterized by:

4. A cylinder, a piston slidably inserted in the cylinder; a piston rod that is movably inserted into the cylinder and has one end connected to the piston; a rebound spring including a coil spring disposed on an outer periphery of the piston rod and an annular lower collar attached to a piston-side end of the coil spring and fitted onto an outer periphery of the piston rod; an annular support attached to an outer periphery of the piston rod and facing the lower collar in the axial direction to support a piston-side end of the lower collar; the support has a cylindrical portion attached to an outer periphery of the piston rod, and an annular receiving portion whose inner periphery is connected to the end of the cylindrical portion opposite the piston side and which faces the piston side end of the lower collar in the axial direction and can abut against the lower collar, a restricting portion that restricts eccentricity of the lower collar relative to the receiving portion; the restricting portion is formed by making the angle formed by the receiving portion and the cylindrical portion in a cross section of the support greater than 90 degrees, and by making the piston-side end surface of the lower collar an inclined surface that gradually becomes farther away from the piston as it goes toward the outer periphery, The inclination angle of the inclined surface of the lower collar is greater than the angle in the cross section of the support minus 90 degrees. A shock absorber characterized by:

5. A cylinder, a piston slidably inserted in the cylinder; a piston rod that is movably inserted into the cylinder and has one end connected to the piston; a rebound spring including a coil spring disposed on an outer periphery of the piston rod and an annular lower collar attached to a piston-side end of the coil spring and fitted onto an outer periphery of the piston rod; an annular support attached to an outer periphery of the piston rod and facing the lower collar in the axial direction to support a piston-side end of the lower collar; the support has a cylindrical portion attached to an outer periphery of the piston rod, and an annular receiving portion whose inner periphery is connected to the end of the cylindrical portion opposite the piston side and which faces the piston side end of the lower collar in the axial direction and can abut against the lower collar, a restricting portion that restricts eccentricity of the lower collar relative to the receiving portion; The restricting portion is formed by folding back the outer periphery of the receiving portion in the cross section of the support, and the angle formed by the outer periphery and the cylindrical portion is set to 180 degrees or more, and the outer periphery is formed facing the outer periphery of the lower collar. A shock absorber characterized by:

6. A cylinder, a piston slidably inserted in the cylinder; a piston rod that is movably inserted into the cylinder and has one end connected to the piston; a rebound spring including a coil spring disposed on an outer periphery of the piston rod and an annular lower collar attached to a piston-side end of the coil spring and fitted onto an outer periphery of the piston rod; an annular support attached to an outer periphery of the piston rod and facing the lower collar in the axial direction to support a piston-side end of the lower collar; the support has a cylindrical portion attached to an outer periphery of the piston rod, and an annular receiving portion whose inner periphery is connected to the end of the cylindrical portion opposite the piston side and which faces the piston side end of the lower collar in the axial direction and can abut against the lower collar, a restricting portion that restricts eccentricity of the lower collar relative to the receiving portion; The lower collar has three or more protrusions on its inner periphery that come into contact with the outer periphery of the piston rod. A shock absorber characterized by:

7. The restricting portion is formed by inclining the outer periphery of the receiving portion toward the side opposite to the piston.

7. The shock absorber according to claim 1 or 6.

8. The restricting portion is formed such that the angle formed by the receiving portion and the cylindrical portion in the cross section of the support is greater than 90 degrees.

7. The shock absorber according to claim 1, 2 or 6.

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