Buffer

Abstract

To provide a buffer which can suppress the loosening of a nut.SOLUTION: The buffer includes: a cylinder 11; a piston 21 that is provided in the cylinder 11; a piston rod 31 that has a rod-like rod part 32 and an extension part 34 of a diameter smaller than the rod part 32 projecting from a first end part 33 in an axial direction of the rod part 32, and in which the extension part 34 is inserted into the piston 21, and a second end part of the rod part 32 in an axial direction is extended from the cylinder 11; and a washer 51 that is provided between the piston 21 and the first end part 33 of the rod part 32, and has a small-diameter part 62 coming in contact with the first end part 33 of the rod part 32, a large-diameter part 63 projecting in a radial outward side from the small-diameter part 62 and formed to be away from the first end part 33 of the rod part 32 in an axial direction, and a projection part 67 provided on the large-diameter part 63 and projecting on the first end part 33 side of the rod part 32.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] There is a washer provided with a protrusion at the axial end (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-172332 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when a lateral force perpendicular to the axis is input to the shock absorber, a load is applied to the nut that secures the piston, which may cause the nut to loosen.

[0005] Therefore, an object of the present invention is to provide a shock absorber that can suppress loosening of a nut. [Means for solving the problem]

[0006] In order to achieve the above object, one aspect of the present invention is configured to include a cylinder, a piston provided within the cylinder and dividing the interior of the cylinder into a first chamber and a second chamber, a piston rod having a rod-shaped rod portion and an extension portion of a smaller diameter than the rod portion that protrudes from a first axial end of the rod portion, the extension portion being inserted into the piston and the second axial end of the rod portion extending from the cylinder, a nut provided on the extension portion and fixing the piston so as to be sandwiched between the piston and the first end of the rod portion, and a washer provided between the piston and the first end of the rod portion, the washer having a small diameter portion that abuts against the first end of the rod portion, a large diameter portion that protrudes radially outward from the small diameter portion and is formed to be axially separated from the first end of the rod portion, and a protrusion provided on the large diameter portion that protrudes toward the first end of the rod portion. [Effects of the Invention]

[0007] According to the present invention, it is possible to suppress loosening of the nut. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing a main part of a shock absorber according to an embodiment of the present invention. [Figure 2] FIG. 2 is a plan view showing a washer of the shock absorber according to the embodiment of the present invention. [Figure 3] FIG. 2 is a cross-sectional view showing a washer of the shock absorber according to the embodiment of the present invention. [Figure 4] 1 is a half-sectional view showing a state in which a piston rod showing a main part of a shock absorber according to an embodiment of the present invention is deformed. FIG. [Figure 5] FIG. 10 is a cross-sectional view showing a modified example of the washer of the shock absorber according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] The embodiment will be described with reference to the drawings. The shock absorber 1 of the embodiment shown in Fig. 1 is a shock absorber used in a suspension device of, for example, a railway vehicle or a two-wheeled or four-wheeled automobile. Specifically, the shock absorber 1 is a shock absorber used in a suspension device of a four-wheeled automobile.

[0010] The shock absorber 1 has a cylindrical cylinder 11 with a bottom. Although not shown, one axial end (the upper end in FIG. 1) of the cylinder 11 is open, and the other axial end (the lower end in FIG. 1) is closed by a bottom (not shown). A rod guide and a seal member (not shown) are fitted into the open side of the cylinder 11. Both the rod guide and the seal member are annular, and the seal member is provided closer to the outside of the cylinder 11 than the rod guide.

[0011] The shock absorber 1 includes a piston 21. The piston 21 is slidably disposed within a cylinder 11. The piston 21 divides the interior of the cylinder 11 into two chambers: a first chamber 22 on one axial side (upper side in FIG. 1 ) and a second chamber 23 on the other axial side (lower side in FIG. 1 ). The first chamber 22 is disposed between the piston 21 and a rod guide (not shown) within the cylinder 11. The second chamber 23 is disposed on the opposite side of the piston 21 from the rod guide within the cylinder 11. A free piston (not shown) is slidably disposed within the cylinder 11, forming the second chamber 23 between itself and the piston 21. Oil L, which serves as a working fluid, is sealed within the cylinder 11 in the first chamber 22 and the second chamber 23. Gas is sealed within the cylinder 11 between the free piston (not shown) and the bottom of the cylinder 11 (not shown). Thus, the shock absorber 1 is a single-cylinder hydraulic shock absorber in which oil L, which serves as a working fluid, is disposed within the cylinder 11. The present invention is not limited to a single-cylinder shock absorber, but can also be applied to a double-cylinder shock absorber.

[0012] The shock absorber 1 has a rod-shaped metal piston rod 31. The piston rod 31 has a rod-shaped rod portion 32 and an extension portion 34 that protrudes from a first axial end portion 33 (the lower end portion in FIG. 1) of the rod portion 32, has a smaller diameter than the rod portion 32, and is inserted into the piston 21.

[0013] The piston rod 31 has a first end 33 of a rod portion 32 disposed within the cylinder 11, and a second end (not shown) (the upper end in FIG. 1) opposite the first end 33 in the axial direction, which extends outward from the cylinder 11. The rod portion 32 of the piston rod 31 is slidably inserted into a rod guide and a seal member (not shown). The rod guide allows the rod portion 32 of the piston rod 31 to move in the axial direction while restricting its movement in the radial direction. The seal member is in sliding contact with the rod portion 32 of the piston rod 31 to restrict leakage of oil L from the cylinder 11.

[0014] The rod portion 32 has, on the radially outer side, a cylindrical main outer peripheral surface 32a and a tapered chamfered portion 32b that extends with a decreasing diameter from the edge of the main outer peripheral surface 32a on the axially extending portion 34 side. The main outer peripheral surface 32a and the chamfered portion 32b have the same central axis. The rod portion 32 has an annular flat abutment surface 32c that extends axially inward of the rod portion 32 from the edge of the chamfered portion 32b on the opposite side from the axial main outer peripheral surface 32a. The abutment surface 32c is provided on a first end portion 33 of the rod portion 32.

[0015] The extending portion 34 has a cylindrical mating surface portion 34a and a male thread 34b on the radially outer side. The mating surface portion 34a extends perpendicularly to the abutment surface 32c from the inner peripheral edge of the abutment surface 32c of the rod portion 32. The male thread 34b extends in a direction away from the abutment surface 32c from the end of the mating surface portion 34a on the opposite side of the abutment surface 32c in the axial direction. The mating surface portion 34a and the male thread 34b have the same central axis. The extending portion 34 has a crimped portion 34c formed at its tip on the opposite side of the rod portion 32 in the axial direction. The outer diameter of the crimped portion 34c is larger than the outer diameter of the male thread 34b.

[0016] The piston 21 has a disk-shaped main body portion 41 and a cylindrical tubular portion 42 extending from the outer circumferential edge of the main body portion 41 to one axial side of the main body portion 41. A fitting hole 45 penetrating the main body portion 41 in the axial direction is formed in the radial center of the main body portion 41. The extending portion 34 of the piston rod 31 is fitted into this fitting hole 45 at the fitting surface portion 34a. A first passage hole 46 penetrating the main body portion 41 in the axial direction is formed in the main body portion 41, outside the fitting hole 45 in the radial direction of the main body portion 41. A plurality of first passage holes 46 are formed in the main body portion 41 at equal intervals in the circumferential direction of the main body portion 41. A second passage hole 47 penetrating the main body portion 41 in the axial direction of the main body portion 41 is formed in the main body portion 41, outside the first passage hole 46 in the radial direction of the main body portion 41. The main body portion 41 is formed with a plurality of second passage holes 47 at equal intervals in the circumferential direction of the main body portion 41 .

[0017] The extending portion 34 of the piston rod 31 is fitted radially inward, and is provided with, in order from the rod portion 32 side in the axial direction, a first washer 51 (washer), a retainer 52, a valve member 54 consisting of a plurality of discs 53, the piston 21, a valve member 56 consisting of a plurality of discs 55, a small diameter disc 57, and a second washer 58. The piston 21 is oriented so that the main body portion 41 of the main body portion 41 and the cylindrical portion 42 is on the valve member 54 side in the axial direction.

[0018] The first washer 51 is a metal disk, and has a fitting hole 61 formed in the radial center thereof, penetrating the first washer 51 in the axial direction of the first washer 51. In the first washer 51, the extension portion 34 of the piston rod fits into the fitting hole 61 at the fitting surface portion 34a.

[0019] 2 and 3, first washer 51 has a cylindrical small diameter portion 62 with a fitting hole 61 formed on the radially inner side, and a disk-shaped large diameter portion 63 that protrudes radially outward from one axial side of small diameter portion 62. Therefore, small diameter portion 62 protrudes from large diameter portion 63 to one axial side of large diameter portion 63.

[0020] The small diameter portion 62 has, on one axial side, an end face 62a in the shape of an annular plane that extends in a direction perpendicular to the axis of the small diameter portion 62. The small diameter portion 62 has, on one axial side, a tapered inclined surface 62b that extends radially outward from the outer circumferential edge of the end face 62a and is inclined axially toward the large diameter portion 63. The small diameter portion 62 has, on the other axial side opposite the end face 62a, an end face 62c in the shape of an annular plane that extends parallel to the end face 62a.

[0021] The large-diameter portion 63 has an annular planar end face 63a extending parallel to the end face 62a of the small-diameter portion 62 on one side from which the small-diameter portion 62 protrudes in the axial direction. This end face 63a extends radially outward from the outer peripheral edge of the inclined surface 62b of the small-diameter portion 62. The large-diameter portion 63 has an end face 63b extending parallel to the end face 63a on the other side opposite the axial end face 63a. The large-diameter portion 63 has a tapered inclined surface 63c on this other side that extends radially inward from the inner peripheral edge of the end face 63b and slopes toward the axial end face 63a. The inner peripheral edge of the inclined surface 63c forms the outer peripheral edge of the end face 62c of the small-diameter portion 62. The end face 62c and the inclined surface 63c form a recessed portion 65 recessed axially inward on the side of the first washer 51 opposite the side from which the small-diameter portion 62 protrudes.

[0022] An end face 62a of the small diameter portion 62 is an end face on one axial side of the first washer 51, and an end face 63b of the large diameter portion 63 is an end face on the other axial side of the first washer 51.

[0023] The first washer 51 has a protruding portion 67 that protrudes from the end face 63a of the large diameter portion 63 toward the opposite side to the end face 63b in the axial direction. The protruding portion 67 extends radially of the large diameter portion 63 and is connected to the inclined surface 62b of the small diameter portion 62. The cross section of the protruding portion 67 taken along a plane perpendicular to the extending direction thereof has an arc shape that bulges outward in the axial direction of the large diameter portion 63 from the end face 63a of the large diameter portion 63. The protruding height of the protruding portion 67 from the end face 63a of the large diameter portion 63 is smaller than the protruding height of the small diameter portion 62 from the end face 63a of the large diameter portion 63 (the axial distance between the end face 63a and the end face 62a). Therefore, the protruding portion 67 protrudes axially from the large diameter portion 63 to a position lower than the small diameter portion 62. The length from the center of first washer 51 to the outer end of protrusion 67 in the radial direction of first washer 51 is smaller than the radius of large diameter portion 63, i.e., the radius of first washer 51. First washer 51 has protrusions 67 of the same shape at three or more locations (specifically, eight locations) equally spaced around the circumference of first washer 51. Therefore, the multiple protrusions 67 radiate out from small diameter portion 62.

[0024] First washer 51 is formed into the above shape by press molding from a single plate material. Therefore, first washer 51 has small diameter portion 62, large diameter portion 63, and multiple protrusions 67 formed from a single plate material.

[0025] 1, the first washer 51 is attached to the extending portion 34 of the piston rod 31 in an orientation in which the small diameter portion 62 protrudes from the large diameter portion 63 toward the rod portion 32 in the axial direction. Then, the end face 62a of the small diameter portion 62 of the first washer 51 abuts in surface contact with the abutment surface 32c of the first end portion 33 of the rod portion 32. In this state, the large diameter portion 63 of the first washer 51 is spaced axially from the abutment surface 32c of the first end portion 33 of the rod portion 32. Furthermore, the protruding portion 67 of the first washer 51 is also spaced axially from the abutment surface 32c of the first end portion 33 of the rod portion 32.

[0026] The retainer 52 is a metal disk with a constant thickness and a hole, and the extension portion 34 of the piston rod is fitted to the radially inner side at the fitting surface 34a. The outer diameter of the retainer 52 is smaller than the outer diameter of the end face 62c of the small diameter portion 62 of the first washer 51.

[0027] When the retainer 52 is attached to the extension portion 34 of the piston rod 31, its one axial end face comes into surface contact with the end face 62c of the small diameter portion 62 of the first washer 51.

[0028] The valve member 54 is made up of a plurality of discs 53, each of which is a perforated disk made of metal and has a uniform thickness. The extending portion 34 of the piston rod 31 fits radially inside at a fitting surface 34a. When the valve member 54 is attached to the extending portion 34 of the piston rod 31, one of the plurality of discs 53, which is closest to the retainer 52 in the axial direction, abuts, at its one axial end face, in surface contact with the end face of the retainer 52 opposite to the axial end face of the first washer 51. At this time, the disc 53 is spaced apart from the first washer 51 in the axial direction. The outer diameter of the disc 53 is larger than the outer diameter of the retainer 52. The outer diameter of the valve member 54 is larger than the outer diameter of the first washer 51.

[0029] The disc 53 of the valve member 54 at the end opposite the retainer 52 in the axial direction abuts against the piston 21. The radius of the disc 53 of at least the end opposite the retainer 52 in the axial direction of the valve member 54 is greater than the radius from the center of the piston 21 to the outer end of the second passage hole 47 in the radial direction of the piston 21. Thus, the valve member 54 opens and closes the second passage hole 47 of the piston 21. A passage hole 71 that is always in communication with the first passage hole 46 of the piston 21 is formed to pass through the valve member 54 in the axial direction.

[0030] The valve member 56 is made up of a plurality of discs 55, each of which is a perforated metal disk of a uniform thickness. The extending portion 34 of the piston rod 31 fits radially inside the discs 55 at the fitting surface 34a. The valve member 56 is housed radially inside the cylindrical portion 42 of the piston 21. When the valve member 56 is attached to the extending portion 34 of the piston rod 31, the disc 55 axially closest to the main body 41 of the piston 21 abuts against the side of the main body 41 of the piston 21 opposite the valve member 54 in the axial direction. The radius of the disc 55 at least at the end of the valve member 56 axially closest to the main body 41 is greater than the radius from the center of the piston 21 to the outermost end of the first passage hole 46 in the radial direction of the piston 21 and is smaller than the radius from the center of the piston 21 to the outermost end of the second passage hole 47 in the radial direction of the piston 21. Thus, the valve member 56 opens and closes the first passage hole 46 without closing the second passage hole 47 of the piston 21 .

[0031] Each of the small-diameter discs 57 is a perforated disk made of metal with a constant thickness, and the extension portion 34 of the piston rod 31 fits radially inside at the fitting surface 34a. The small-diameter disc 57 is housed radially inside the cylindrical portion 42 of the piston 21. One axial end face of the small-diameter disc 57 abuts in surface contact with the end face of the disc 55 at the end of the valve member 56 opposite to the main body portion 41 in the axial direction, opposite to the main body portion 41. The small-diameter disc 57 has an outer diameter smaller than the outer diameters of any of the discs 55 that constitute the valve member 56.

[0032] The second washer 58 is a perforated disk made of metal with a constant thickness, and the extending portion 34 of the piston rod 31 fits into the radially inner side at the fitting surface 34a. A portion of the second washer 58 is housed inside the radial direction of the cylindrical portion 42 of the piston 21. One axial end face of the second washer 58 abuts in surface contact with the end face of the small-diameter disc 57 on the axial opposite side from the valve member 56. The outer diameter of the second washer 58 is larger than the outer diameter of the small-diameter disc 57 and is equal to the outer diameter of the valve member 56.

[0033] When the first washer 51, retainer 52, valve member 54 consisting of multiple discs 53, piston 21, valve member 56 consisting of multiple discs 55, small diameter disc 57, and second washer 58 are placed on the extending portion 34 of the piston rod 31 before the crimped portion 34c is formed, in that order from the rod portion 32 side in the axial direction, the male thread 34b of the extending portion 34 protrudes outward from the second washer 58. A nut 75 is screwed onto this male thread 34b. One end face of the nut 75 then comes into surface contact with the end face of the second washer 58 opposite the small diameter disc 57 in the axial direction. When the nut 75 is tightened in this state, at least the inner circumferential sides of the first washer 51, the retainer 52, the valve member 54 consisting of the plurality of discs 53, the piston 21, the valve member 56 consisting of the plurality of discs 55, the small-diameter disc 57, and the second washer 58 are clamped and fixed in the axial direction to the first end 33 of the rod portion 32 of the piston rod 31 and the nut 75. In other words, the nut 75 is provided on the extending portion 34 of the piston rod 31, and fixes the piston 21 so as to sandwich it between the first end 33 of the rod portion 32. Thereafter, the portion of the extending portion 34 of the piston rod 31 that protrudes beyond the nut 75 is expanded radially outward by crimping, thereby forming a crimped portion 34c.

[0034] The first washer 51 in the attached state, which is attached to the piston rod 31 with the nut 75 in this manner, is disposed between the piston 21 and the first end 33 of the rod portion 32 of the piston rod 31. The first washer 51 in this attached state also has a small diameter portion 62 that abuts against the first end 33 of the rod portion 32, a large diameter portion 63 that protrudes radially outward from the small diameter portion 62 and is formed to be spaced axially apart from the first end 33 of the rod portion 32, and a protruding portion 67 that is provided on the large diameter portion 63 and protrudes toward the first end 33 of the rod portion 32. The protruding portion 67 of the first washer 51 and the first end 33 of the rod portion 32 of the piston rod 31 are spaced apart when the shock absorber 1 is attached to the piston rod 31, i.e., when the shock absorber 1 is not attached to the vehicle.

[0035] In the shock absorber 1, during the extension stroke in which the piston rod 31 extends from the cylinder 11, the piston 21 moves toward the first chamber 22 within the cylinder 11. When the pressure on the first chamber 22 side becomes higher than the pressure on the second chamber 23 side by a predetermined value or more, the outer periphery of the valve member 56 moves away from the main body portion 41 of the piston 21 in the axial direction, causing the oil L on the first chamber 22 side to flow toward the second chamber 23 side via the passage hole 71 of the valve member 54 and the first passage hole 46 of the piston 21. At this time, the valve member 56 suppresses the flow of the oil L through the passage hole 71 and the first passage hole 46, thereby generating a damping force. The second washer 58 abuts against the valve member 56 to suppress deformation of the valve member 56 beyond a predetermined amount.

[0036] In the shock absorber 1, during the compression stroke in which the piston rod 31 enters the cylinder 11, the piston 21 moves toward the second chamber 23 within the cylinder 11. When the pressure on the second chamber 23 side becomes higher than the pressure on the first chamber 22 side by a predetermined value or more, the outer periphery of the valve member 54 moves away from the main body portion 41 of the piston 21 in the axial direction, causing the oil L on the second chamber 23 side to flow toward the first chamber 22 side via the second passage hole 47 of the piston 21. At that time, the valve member 54 suppresses the flow of the oil L via the second passage hole 47, thereby generating a damping force. The first washer 51 abuts against the valve member 54 to suppress deformation of the valve member 54 beyond a predetermined amount.

[0037] In the shock absorber 1, a second end (not shown) of the rod portion 32 of the piston rod 31 extending from the cylinder 11 is connected to either the vehicle body side or the wheel side of the vehicle, and the cylinder 11 is connected to the other of the vehicle body side or the wheel side of the vehicle. When the shock absorber 1 is mounted on a vehicle, a lateral force along a direction perpendicular to the axis may be applied between the piston rod 31 and the cylinder 11. When this occurs, the piston rod 31 deforms so that the rod portion 32 tilts relative to the extension portion 34, whose tilt is suppressed by the piston 21 fitted in the cylinder 11. When this lateral force reaches a predetermined value, the first end 33 of the rod portion 32 abuts against the protruding portion 67 of the first washer 51, as shown in FIG. 4 . That is, the protruding portion 67 of the first washer 51 and the first end 33 of the rod portion 32 of the piston rod 31 abut against each other when a predetermined lateral force is applied to the shock absorber 1.

[0038] The washer described in the aforementioned Patent Document 1 is a washer with a protrusion at its axial end. Because the seating portion of this washer is protruding, variations in the protrusion shape make it difficult to stabilize the axial force, making it unsuitable for use in shock absorbers in which the axial force is controlled by the tightening torque of the nut. Furthermore, the base material of this washer is gouged out during assembly, which can cause contamination. This contamination can become trapped between the piston and the valve member, potentially resulting in poor damping force. This also makes it unsuitable for use in shock absorbers. Incidentally, when a lateral force perpendicular to the axis is applied to the shock absorber, a load is applied to the nut securing the piston, potentially causing the nut to loosen.

[0039] In contrast, in the shock absorber 1 of this embodiment, the washer 51, which is provided between the piston 21 and the first end 33 of the rod portion 32 of the piston rod 31, has a small-diameter portion 62 that abuts against the first end 33 of the rod portion 32, a large-diameter portion 63 that protrudes radially outward from the small-diameter portion 62 and is formed to be spaced axially apart from the first end 33 of the rod portion 32, and a protruding portion 67 that is provided on the large-diameter portion 63 and protrudes toward the first end 33 of the rod portion 32. Therefore, when a predetermined lateral force is input to the shock absorber 1, the first end 33 of the rod portion 32 of the piston rod 31 abuts against the protruding portion 67 of the first washer 51, and the frictional force generated thereby restricts relative rotation of the first washer 51, the retainer 52, the valve member 54, the piston 21, the valve member 56, the small-diameter disk 57, the second washer 58, and the nut 75 with respect to the piston rod 31. This makes it possible to suppress loosening of the nut 75 with respect to the piston rod 31.

[0040] Furthermore, in the shock absorber 1 of this embodiment, the protrusion 67 of the first washer 51 and the first end 33 of the rod portion 32 of the piston rod 31 are spaced apart when the shock absorber 1 is mounted and no predetermined lateral force is applied thereto. This prevents the protrusion 67 of the first washer 51 from affecting the axial force when the shock absorber 1 is mounted. In addition, the small-diameter portion 62 of the first washer 51 abuts the flat end surface 62a against the flat abutment surface 32c of the first end 33 of the rod portion 32 of the piston rod 31. This prevents the first washer 51 from being gouged by the first end 33 of the rod portion 32 of the piston rod 31 during assembly, which is unlikely to cause contamination during assembly. This reduces the occurrence of poor damping force.

[0041] Furthermore, in the shock absorber 1 of the embodiment, the first washer 51 has the small diameter portion 62, the large diameter portion 63, and the protruding portion 67 formed from a single plate material, so that the manufacturing cost can be reduced.

[0042] Furthermore, in the shock absorber 1 of the embodiment, the first washer 51 has the protrusions 67 at three or more locations, and therefore, the effect of suppressing loosening of the nut 75 against lateral forces in many directions can be obtained.

[0043] 5, a modified first washer 51A having a shape in which the first washer 51 and the retainer 52 are integrated together can be used instead of the first washer 51 and the retainer 52. In the first washer 51A, parts that are the same as those of the first washer 51 are designated by the same names and symbols as those of the first washer 51.

[0044] The first washer 51A has a small diameter portion 62A and a large diameter portion 63A, which differ from the small diameter portion 62 and the large diameter portion 63 in that the recessed portion 65 shown in FIG. 3 is not formed. The end face 63Ab of the large diameter portion 63A opposite the axial end face 63a has a shape in which the end face 63b extends radially inward. The small diameter portion 62A also protrudes from the end face 63Ab of the large diameter portion 63A opposite the axial end face 62a. As a result, the fitting hole 61A on the radially inner side of the small diameter portion 62A is longer in the axial direction than the fitting hole 61A. The inner peripheral edge of the end face 63Ab of the large diameter portion 63A is connected to the outer peripheral surface of the small diameter portion 62A. The small diameter portion 62A has an end face 62Ac opposite to the axial end face 62a, which is flat and parallel to the end face 62a, and this end face 62Ac abuts in surface contact with the disk 53 on the first washer 51A side of the valve member 54 shown in Figure 1.

[0045] Therefore, first washer 51A is formed so that the axial thickness of small diameter portion 62A is greater than the combined axial thickness of large diameter portion 63A and protruding portion 67. First washer 51A is formed by cutting from a single piece of material. First washer 51A is formed so that the axial thickness of small diameter portion 62A is greater than the axial thickness of large diameter portion 63A and protruding portion 67, eliminating the need for retainer 52 and reducing the number of parts. [Explanation of symbols]

[0046] 1... shock absorber, 11... cylinder, 21... piston, 22... first chamber, 23... second chamber, 31... piston rod, 32... rod portion, 33... first end portion, 34... extension portion, 51, 51A... first washer (washer), 62, 62A... small diameter portion, 63, 63A... large diameter portion, 67... protrusion portion, 75... nut 75.

Claims

1. A cylinder; a piston provided in the cylinder and dividing the interior of the cylinder into a first chamber and a second chamber; a piston rod having a rod-shaped rod portion and an extension portion having a smaller diameter than the rod portion and projecting from a first axial end of the rod portion, the extension portion being inserted into the piston, and a second axial end of the rod portion extending from the cylinder; a nut provided on the extension portion and configured to clamp and fix the piston between the extension portion and the first end of the rod portion; a washer provided between the piston and the first end of the rod portion, the washer having a small diameter portion that abuts against the first end of the rod portion, a large diameter portion that protrudes radially outward from the small diameter portion and is formed to be spaced apart in the axial direction from the first end of the rod portion, and a protrusion that is provided on the large diameter portion and protrudes toward the first end of the rod portion; A buffer comprising:

2. 2. The shock absorber according to claim 1, A shock absorber in which the protrusion and the first end of the rod are spaced apart in an attached state.

3. 3. The shock absorber according to claim 2, The shock absorber has abutment between the protrusion and the first end of the rod when a predetermined lateral force is input to the shock absorber.

4. 3. The shock absorber according to claim 1 or 2, The washer is a shock absorber in which the small diameter portion, the large diameter portion, and the protruding portion are formed from a single plate material.

5. 3. The shock absorber according to claim 1 or 2, A shock absorber in which the axial thickness of the small diameter portion is greater than the axial thickness of the large diameter portion and the protruding portion.

6. 3. The shock absorber according to claim 1 or 2, A shock absorber having three or more of the protruding portions.

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