Shock absorber

Abstract

A shock absorber (D) according to the present invention is provided with: an inner tube (7) having an opening (7a) in a side part thereof; a cylindrical collar (19) which is in contact with the outer periphery of the inner tube (7) and surrounds the opening (7a); an outer tube (1) which covers the inner tube (7) and has a through-hole (1a); a housing (20) which is attached to the outer periphery of the outer tube (1) and surrounds the through-hole (1a); a valve assembly (41) which is accommodated in the housing (20) and has a fitting part (41b) fitted to the inner periphery or the outer periphery of the collar (19); and a seal ring (50) that is attached to one of the collar (19) and the fitting part (41b) and is in close contact with the other of the collar (19) and the fitting part (41b). One of mutually facing surfaces (19a, 41b1) of the collar (19) and the fitting part (41b) is provided with inclined surfaces (41b3, 41b4) on both sides of the seal ring (50).

Description

Shock absorber

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

[0002] In a shock absorber that exhibits a damping force for suppressing vibration, for example, there is one in which a valve assembly having a damping valve capable of adjusting the damping force is attached to the side portion of an outer tube. In this shock absorber, the damping force can be adjusted up and down by adjusting the resistance given to the flow of the working oil generated during the expansion and contraction of the shock absorber by the damping valve.

[0003] In such a shock absorber, as disclosed in, for example, JP2017-57864A, if the entire damping valve is provided inside the outer tube, the outer diameter becomes large or the overall length becomes long, resulting in poor mounting performance on a vehicle. Therefore, the damping valve is projected radially outward from the side portion of the outer tube to shorten the axial length without sacrificing the stroke length.

[0004] Specifically, the shock absorber includes a cylinder that is cylindrical and whose interior is partitioned by a piston into an extension chamber and a compression chamber, an inner tube disposed between the cylinder and the outer tube and forming an annular passage that communicates with the inside of the extension chamber between the inner tube and the cylinder, and a reservoir formed between the inner tube and the outer tube, and a damping valve is provided between the annular passage and the reservoir.

[0005] JP2017-57864A

[0006] In the conventional shock absorber described above, the valve assembly having a damping valve is fitted into a cylindrical collar that surrounds an opening provided in the side portion of the inner tube, and the base end portion is fitted into a cylindrical housing that surrounds a through hole provided in the outer tube, and thus is housed inside the housing.

[0007] In conventional shock absorbers configured in this way, the valve assembly is fitted to both a cylindrical collar, which is welded to the outer circumference of a cylindrical inner tube, and a cylindrical housing, which is welded to the outer circumference of a cylindrical outer tube. Therefore, in conventional shock absorbers, if the relative inclination between the collar and the housing is large, the valve assembly cannot be fitted, which requires high dimensional accuracy and results in high manufacturing costs.

[0008] Therefore, the present invention aims to provide a shock absorber that can reduce manufacturing costs.

[0009] To achieve the above objective, the shock absorber of the present invention comprises an inner tube having an opening on its side, a tubular collar that abuts against the outer circumference of the inner tube and surrounds the opening, an outer tube that covers the outer circumference of the inner tube and has a through hole radially opposite to the collar, a tubular housing that is attached to the outer circumference of the outer tube and surrounds the through hole, a valve assembly housed in the housing and having a fitting portion that fits onto the inner or outer circumference of the collar, and a seal ring that is attached to one of the collar and the fitting portion and is in close contact with the other of the collar and the fitting portion, wherein one of the annular opposing surfaces of the collar and the fitting portion that face each other has inclined surfaces on both sides of the seal ring or the seal ring opposing surface that faces the seal ring, which move away from the other annular opposing surface of the collar and the fitting portion as they move axially away from the seal ring or the seal ring opposing surface.

[0010] With a buffer configured in this way, by providing an inclined surface on one of the opposing surfaces of the fitting portion between the collar and the valve assembly, and by attaching a seal ring to one of them and providing a seal ring-facing surface on the other, a play is created that allows the valve assembly to pivot relative to the collar. Even if there is an error in the arrangement of the collar and the housing and the axis of the housing is slightly tilted relative to the axis of the collar, the valve assembly can be accommodated in the housing without difficulty, and the valve assembly can be easily assembled to the housing and collar.

[0011] Figure 1 is a cross-sectional view of a buffer in one embodiment. Figure 2 is an enlarged cross-sectional view of the collar and valve assembly of the buffer in one embodiment. Figure 3 is a diagram illustrating the possible orientations that the valve assembly can take relative to the collar of the buffer in one embodiment. Figure 4 is an enlarged cross-sectional view of a part of the collar and valve assembly in the first modified example of the buffer in one embodiment. Figure 5 is an enlarged cross-sectional view of a part of the collar and valve assembly in the second modified example of the buffer in one embodiment. Figure 6 is an enlarged cross-sectional view of a part of the collar and valve assembly in the third modified example of the buffer in one embodiment. Figure 7(a) is an enlarged cross-sectional view of a part of the collar and valve assembly in the fourth modified example of the buffer in one embodiment. Figure 7(b) is an enlarged cross-sectional view of a part of the collar and valve assembly in the fifth modified example of the buffer in one embodiment. Figure 7(c) is an enlarged cross-sectional view of a part of the collar and valve assembly in the sixth modified example of the buffer in one embodiment. Figure 7(d) is an enlarged cross-sectional view of a part of the collar and valve assembly in the eighth modified example of the buffer in one embodiment. Figure 8(a) is an enlarged cross-sectional view of a part of the collar and valve assembly in the ninth modified example of the buffer in one embodiment. Figure 8(b) is an enlarged cross-sectional view of a portion of the collar and valve assembly in the buffer of the 10th modified example of one embodiment. Figure 8(c) is an enlarged cross-sectional view of a portion of the collar and valve assembly in the buffer of the 11th modified example of one embodiment. Figure 8(d) is an enlarged cross-sectional view of a portion of the collar and valve assembly in the buffer of the 12th modified example of one embodiment.

[0012] The shock absorber D of the present invention will be described below with reference to the figures. In one embodiment, as shown in Figures 1 and 2, the shock absorber D comprises an inner tube 7 having an opening 7a on its side, a cylindrical collar 19 that abuts against the outer circumference of the inner tube 7, an outer tube 1 that covers the outer circumference of the inner tube 7 and has a through hole 1a radially opposite to the collar 19, a cylindrical housing 20 attached to the outer circumference of the outer tube 1 and surrounding the through hole 1a, a valve assembly 41 housed in the housing 20 and having a fitting portion 41b that fits onto the inner circumference of the collar 19, and a seal ring 50 that is attached to the fitting portion 41b and is in close contact with the collar 19.

[0013] The following describes in detail each part of the shock absorber D. In this embodiment, in addition to the configuration described above, the shock absorber D includes a cylinder 5 housed in the inner tube 7, a rod 2 inserted into the cylinder 5 so as to be movable in the axial direction, a piston 6 connected to the tip of the rod 2 and inserted into the cylinder 5 so as to be movable, dividing the inside of the cylinder 5 into an extension chamber R1 and a compression chamber R2 filled with liquid, and a reservoir R formed between the outer tube 1 and the inner tube 7.

[0014] The extension chamber R1 and the compression chamber R2 are filled with liquid, and the reservoir R is filled with liquid and gas. The liquid used to operate the buffer D is specifically, for example, hydraulic oil, but may also be water, an aqueous solution, or the like.

[0015] Furthermore, the cylinder 5 is housed within a bottomed cylindrical outer tube 1 positioned on its outer circumference. As previously mentioned, an inner tube 7 is inserted between the cylinder 5 and the outer tube 1, forming an annular passage 10 through the annular gap between the cylinder 5 and the inner tube 7, and a reservoir R is formed through the annular gap between the inner tube 7 and the outer tube 1. Near the upper end of the cylinder 5, a hole 5a is provided that communicates with the extension chamber R1 and the annular passage 10. In addition, the outer tube 1 covers the outer circumference of the cylinder 5 along its entire length, housing the entire cylinder 5 inside. The annular passage 10 and the reservoir R are filled with liquid, similar to the inside of the cylinder 5.

[0016] Furthermore, a valve case 8 is fitted to the lower end of the cylinder 5 and inner tube 7 in Figure 1, and a rod guide 9, which slidably supports the rod 2, is fitted to the upper end of the cylinder 5 and inner tube 7 in Figure 1. The cylinder 5 and inner tube 7 are positioned concentrically in the radial direction, sandwiched between the valve case 8 and the rod guide 9. The lower end of the cylinder 5 and the lower end of the inner tube 7 are both closed by the valve case 8, and the valve case 8 separates the pressure chamber R2 inside the cylinder 5 from the reservoir R formed outside the cylinder 5 and inside the outer tube 1.

[0017] In this manner, the valve case 8 and rod guide 9, which sandwich the cylinder 5 and inner tube 7, are inserted into the inner circumference of the outer tube 1. When the upper end of the outer tube 1 is crimped, the cylinder 5, inner tube 7, valve case 8, and rod guide 9 are clamped between the crimped portion and the bottom of the outer tube 1, and are fixed inside the outer tube 1. The space between the rod guide 9 and the rod 2, and the space between the rod guide 9 and the outer tube 1 are sealed by a sealing member (not shown), preventing leakage of liquid from inside the buffer D. Alternatively, instead of crimping the upper opening of the outer tube 1, a cap may be screwed onto the upper opening of the outer tube 1, and the rod guide 9, cylinder 5, inner tube 7, and valve case 8 may be clamped between this cap and the bottom of the outer tube 1, thereby fixing these components inside the outer tube 1.

[0018] The piston 6 is annular in shape and connected to the rod 2, dividing the inside of the cylinder 5 into an extension chamber R1 at the top of Figure 1 and a compression chamber R2 at the bottom of Figure 1. It is equipped with an extension damping passage 6a that resists the flow of liquid passing through it while allowing only the flow of liquid from the extension chamber R1 to the compression chamber R2, and a compression passage 6b that blocks the flow of liquid in the opposite direction while allowing only the flow of liquid from the compression chamber R2 to the extension chamber R1.

[0019] Next, as shown in Figure 1, the valve case 8 is annular and has two stepped portions on its outer circumference that are not indicated, and fits into the inner circumference of the lower end of the cylinder 5 and the inner circumference of the lower end of the inner tube 7, as well as the inner circumference of the lower end of the outer tube 1. The valve case 8 includes a pressure-side damping passage 8a that allows only the flow of liquid from the pressure-side chamber R2 to the reservoir R while providing resistance to the liquid flow, and a suction passage 8b that allows the flow of liquid from the reservoir R to the pressure-side chamber R2 while preventing the flow of liquid in the reverse direction.

[0020] The inner tube 7 has an opening 7a on its lower side in Figure 1 that connects the inside and outside of the inner tube 7. As described above, it covers the outer circumference of the cylinder 5 and is sandwiched between the rod guide 9 and the valve case 8, forming an annular passage 10 between it and the cylinder 5.

[0021] A cylindrical collar 19 is welded to the side of the inner tube 7. The collar 19 is cylindrical with a uniform inner diameter and abuts against the side of the inner tube 7, surrounding the opening 7a of the inner tube 7. The fitting portion 41b of the tip of the valve assembly 41, which contains the damping valve 4, is fitted into the collar 19. The collar 19 is fixedly attached to the inner tube 7 by welding, but if it is not separated from the inner tube 7 after the shock absorber D is assembled, it may have a seal that tightly adheres to the position surrounding the opening 7a, which was the outer circumference of the inner tube 7, and be pressed against the inner tube 7. Alternatively, the collar 19 may be integrally provided with the inner tube 7 by making a hole in the inner tube 7 and performing a burring process.

[0022] The annular passage 10 is connected to the extension chamber R1 through a hole 5a provided in the cylinder 5, and also to the reservoir R through a passage 41c provided in the valve assembly 41. Therefore, in the shock absorber D of this embodiment, the extension chamber R1 is connected to the reservoir R through a damping passage 3 formed by the hole 5a provided in the cylinder 5, the annular passage 10, and the passage 41c provided in the valve assembly 41.

[0023] In addition, while the hole 5a provided in the cylinder 5 is used to connect the annular passage 10 inside the inner tube 7 with the extension chamber R1, instead of the hole 5a, a passage may be provided in the rod guide 9 to connect the extension chamber R1 with the annular gap between the cylinder 5 and the inner tube 7, thereby connecting the annular passage 10 with the extension chamber R1.

[0024] Next, the outer tube 1 has a through hole 1a that penetrates the side portion of the inner tube 7 that is radially facing the opening 7a and collar 19. A cylindrical housing 20 is mounted on the side of the outer tube 1, surrounding the through hole 1a and projecting radially. The housing 20 is cylindrical, with one end cut off by a cylindrical surface so that the open end of one end follows the outer circumference of the outer tube 1. The housing 20 is welded to the outer tube 1 with this end in contact with the outer circumference of the outer tube 1, specifically the outer circumference side of the through hole 1a.

[0025] Therefore, the interior of the housing 20 is connected to the outer tube 1 through the through hole 1a and faces the opening 7a radially. In addition, an annular groove 20a is provided on the outer circumference of the other end of the housing 20.

[0026] A valve assembly 41 is housed inside the housing 20. As shown in Figure 2, the valve assembly 41, together with the molded coil 42, constitutes a damping valve 4 that allows adjustment of the damping force generated by the shock absorber D.

[0027] The valve assembly 41 includes a valve case 41a having a fitting portion 41b at its tip that fits into the collar 19, a passage 41c that opens from the tip of the fitting portion 41b in the valve case 41a and extends laterally to the rear end of the fitting portion 41b, connecting the annular passage 10 and the reservoir R, a valve body 41d provided inside the valve case 41a in the middle of the passage 41c, a fixed iron core 41e having a larger outer diameter than the valve case 41a and mounted on the rear end of the valve case 41a and fitted into the inner circumference of the housing 20, a cylindrical body 41f made of a non-magnetic material attached to the right end of the fixed iron core 41e in Figure 2, a movable iron core 41g inserted into the cylindrical body 41f so as to be movable in the axial direction, and a cap 41h that closes the right end of the cylindrical body 41f in Figure 2.

[0028] The valve case 41a in the valve assembly 41 has a smaller outer diameter at the tip and is provided with a fitting portion 41b formed at the tip. When the fitting portion 41b is inserted into the collar 19, its outer circumferential surface 41b1 faces the inner circumferential surface 19a of the collar 19. The outer circumferential surface of the fitting portion 41b and the inner circumferential surface of the collar 19 face each other radially and function as opposing surfaces.

[0029] Furthermore, the fitting portion 41b includes an annular groove 41b2 provided on the outer circumference along the circumferential direction, and inclined surfaces 41b3 and 41b4 formed on the outer peripheral surface 41b1, sandwiching the annular groove 41b2, as opposing surfaces.

[0030] Within the annular groove 41b2, a seal ring 50 is housed that, when the fitting portion 41b is inserted into the collar 19, makes close contact with the inner circumferential surface 19a of the collar 19, which is the opposing surface. Furthermore, the inclined surfaces 41b3 and 41b4 on both sides of the outer circumferential surface 41b1 of the fitting portion 41b, which sandwich the seal ring 50, are tapered surfaces that incline so that they move further away from the inner circumferential surface 19a of the collar 19 as they move axially away from the seal ring 50. In other words, in Figure 2, the inclined surface 41b3 on the left side of the seal ring 50 is inclined to move further away from the inner circumferential surface 19a, which is the opposing surface of the collar 19, as it moves towards the tip of the fitting portion 41b, which is to the left of the seal ring 50, and the inclined surface 41b4 on the right side of the seal ring 50 is inclined to move further away from the inner circumferential surface 19a, which is the opposing surface of the collar 19, as it moves towards the base end of the fitting portion 41b, which is to the right of the seal ring 50.

[0031] Furthermore, the maximum outer diameter of the fitting portion 41b is smaller than the maximum outer diameter of the seal ring 50. Therefore, the shape of the tip side of the fitting portion 41b is tapered, and the shape of the base side of the fitting portion 41b is tapered at the base end, and the shape of the outer peripheral surface 41b1, which is the opposing surface of the fitting portion 41b including the seal ring 50, is a roughly spindle shape with a central bulge where the outer diameter of the seal ring 50 is at its maximum.

[0032] Furthermore, the inner diameter of the inner circumferential surface 19a of the collar 19 is larger than the maximum outer diameter of the fitting portion 41b by the amount of play, and smaller than the maximum outer diameter of the seal ring 50. Therefore, when the fitting portion 41b is inserted into the collar 19, the fitting portion 41b can be displaced radially by the amount of play, and the seal ring 50 comes into close contact with the inner circumferential surface 19a of the collar 19, sealing the space between the valve assembly 41 and the collar 19. Thus, the space between the fitting portion 41b and the collar 19 is sealed by the seal ring 50, preventing the annular passage 10 and the reservoir R from communicating by bypassing the passage 41c through the space between the fitting portion 41b and the collar 19.

[0033] Therefore, when the fitting portion 41b is inserted into the collar 19, the seal ring 50 is compressed and deformed to make close contact with the inner circumferential surface 19a of the collar 19. Furthermore, since the outer circumferential surface 41b1 of the fitting portion 41b has inclined surfaces 41b3 and 41b4 on both sides of the seal ring 50, the valve assembly 41 can pivot relative to the collar 19 within the range until the inner circumferential surface 19a contacts the inclined surfaces 41b3 and 41b4. Specifically, when the collar 19 and the fitting portion 41b are arranged coaxially, the valve assembly 41 can pivot relative to the collar 19 within the range of the sum of the angles formed between the inner circumferential surface of the collar 19 and the inclined surfaces 41b3 and 41b4, and the valve assembly 41 can be fitted in an inclined position relative to the collar 19 within the range from the position shown by the dashed line in Figure 3 to the position shown by the double dashed line.

[0034] Furthermore, the inclined surfaces 41b3 and 41b4 may be curved surfaces in addition to the tapered surfaces described above, as long as they allow the valve assembly 41 to be fitted to the collar 19 in an inclined position. Also, if the axial length of the fitting portion 41b is longer than the axial length of the collar 19, and the valve assembly 41 can be fitted to the collar 19 in an inclined position, the inclined surfaces may be formed only on the outer circumferential surface portion of the fitting portion 41b that faces the collar 19 in the radial direction, and the outer circumferential surface portion of the fitting portion 41b that does not face the collar 19 in the radial direction does not need to have inclined surfaces.

[0035] Furthermore, since the seal ring 50 is an O-ring in this embodiment, the shape of the outer circumference of the fitting portion 41b including the seal ring 50 is approximately spindle-shaped. Therefore, even if the valve assembly 41 is fitted diagonally to the collar 19, the seal ring 50 can adhere closely to the inner circumferential surface 19a of the collar 19, providing a tight seal between the fitting portion 41b and the collar 19. If the seal ring 50 is a U-packing, when the valve assembly 41 is fitted diagonally to the collar 19 and tilted significantly relative to the collar 19, the degree of adhesion of the lip of the U-packing to the inner circumferential surface 19a of the collar 19 may vary in the circumferential direction. However, by using an O-ring, sealing performance can be ensured even if the tilt angle of the valve assembly 41 relative to the collar 19 is large.

[0036] The valve case 41a is equipped with a fitting portion 41b configured as described above, encloses a passage 41c, holds the valve body 41d, and is structured such that it allows for oscillating motion even when fitted into the collar 19, and prevents the annular passage 10 and the reservoir R from communicating without going through the passage 41c. In that respect, the structure and shape of the valve case 41a can be arbitrarily modified.

[0037] The valve body 41d comprises a valve element 41d1 that seats away from a valve seat (not shown) provided in the passage 41c, and a spring 41d2 that biases the valve element 41d1 in the direction of closing the valve. The valve element 41d1 is in contact with the movable iron core 41g so as to be able to receive a thrust force from the movable iron core 41g in the direction of opening the valve. Furthermore, the valve element 41d1 is designed to receive a force in the direction of opening the valve from the pressure of the extension chamber R1 which is upstream of the passage 41c. The structure of the valve body 41d can be modified as appropriate, and the valve body 41d may be an assembly of multiple valves.

[0038] In this embodiment, the damping valve 4 is equipped with a solenoid S to adjust the damping force, but it may also be a damping valve that does not have a solenoid S and allows the user to adjust the damping force manually, or it may be a damping valve that does not have a damping force adjustment function.

[0039] The fixed core 41e in the valve assembly 41 is made of a soft magnetic material and is attached to the valve case 41a. When the valve case 41a is inserted into the housing 20 and the fitting portion 41b is fitted into the collar 19, the outer circumference is fitted into the housing 20 and the assembly is housed within the housing 20. In this way, the valve assembly 41 is fitted to the inner circumference of the housing 20 and centered radially. The fixed core 41e also has a through hole 41e1 in its center. The fixed core 41e may be integrally and inseparably connected to the valve case 41a and constitute a single part.

[0040] The cylindrical body 41f is a cylinder formed of a non-magnetic material and is fixed to the right end of the fixed core 41e in Figure 2. The movable core 41g is formed of a soft magnetic material and its outer circumference is in sliding contact with the inner circumference of the cylindrical body 41f, allowing it to move axially within the cylindrical body 41f. The movable core 41g is axially opposed to the fixed core 41e and is equipped with a push rod 41g1 that is inserted into the through hole 41e1 of the fixed core 41e and contacts the valve body 41d1 in the valve body 41d. In this embodiment, the movable core 41g is equipped with a push rod 41g1, but a push rod that contacts the movable core 41g may be provided on the valve body 41d1 side, or the push rod may be omitted as long as the movable core 41g and the valve body 41d1 are in contact. The cap 41h is attached to the right end of the cylindrical body 41f in Figure 2, closing the opening of the cylindrical body 41f and preventing the movable iron core 41g from falling out of the cylindrical body 41f.

[0041] The molded coil 42 comprises a coil 42a, an annular molded resin 42b enclosing the coil 42a, and a cylindrical coupler 42d enclosing a terminal 42c that protrudes upward from the right end side of the molded resin 42b in Figure 2 and is connected to the coil 42a.

[0042] When the molded resin 42b of the molded coil 42 is fitted onto the outer circumference of the cylindrical body 41f of the valve assembly 41, the molded coil 42, the fixed core 41e, and the movable core 41g form a solenoid S.

[0043] When the solenoid S configured as described above is energized to the coil 42a, the fixed iron core 41e is magnetized to attract the movable iron core 41g, and the force for attracting the movable iron core 41g acts on the valve body 41d1 as a thrust force. The valve body 41d1 receiving the thrust force from the solenoid S is driven in the valve opening direction against the biasing force of the spring 41d2. Thus, the larger the amount of current supplied to the coil 42a, the smaller the valve opening pressure when the valve body 41d opens the passage 41c. By adjusting the amount of current supplied to the coil 42a, the valve opening pressure of the valve body 41d can be adjusted, and the pressure in the extension chamber R1 upstream of the damping valve 4 can be adjusted. When the energization to the coil 42a is stopped, the valve body 41d1 moves in the valve closing direction under the biasing force of the spring 41d2 since the thrust force for attracting the movable iron core 41g disappears, thereby blocking the passage 41c.

[0044] In the present embodiment, when the energization to the coil 42a is stopped, the valve body 41d is closed by the spring 41d2. However, the spring 41d2 may be eliminated and a spring for biasing the valve body 41d1 and the movable iron core 41g in the valve opening direction may be provided, and the fixed iron core may be provided on the side of the movable iron core 41g opposite to the valve so as to drive the valve body 41d1 in the valve closing direction when energized. In this case, the larger the amount of current supplied to the coil 42a, the larger the valve opening pressure of the valve body 41d can be made, and when the energization to the coil 42a is stopped, the valve body 41d can be closed to minimize the valve opening pressure of the valve body 41d.

[0045] Next, a sleeve 21 is attached to the outer circumference of the right end of the housing 20 in Figure 2. The sleeve 21 is cylindrical and its inner diameter is set to a diameter that can be fitted to the outer circumference of the housing 20. After being fitted to the outer circumference of the housing 20, one end, near the left end in Figure 2, is formed by crimping from the outer circumference side, and has a crimped portion 21a that is plastically deformed so as to fit into the annular groove 20a of the housing 20. In this way, the sleeve 21 is attached and fixed to the outer circumference of the housing 20 by the crimped portion 21a formed by the crimping process fitting into the annular groove 20a. Furthermore, the sleeve 21 has an annular cap mounting portion 21b that protrudes axially from the outer circumference of the other end, which is the right end in Figure 2, and is thinner than the left side, and an outlet hole 21c formed by a notch that opens at the other end.

[0046] The sleeve 21 has a flange 21d at the left end of Figure 2, which is one end of the sleeve 21 before it is fixed to the housing 20 by crimping. A crimped portion 21a is formed by crimping, which involves bending the flange 21d toward the housing 20, and the sleeve 21 is then fixed to the housing 20. An annular groove 21e is provided on the inner circumference of the sleeve 21, next to the flange 21d, which forms a weak portion to facilitate bending of the flange 21d and allows the inner circumference of the bent flange 21d to move in. The inner circumference of the flange bent by plastic deformation becomes the crimped portion 21a, which fits into the annular groove 20a of the housing 20 and tightens the outer circumference of the housing 20, so that the sleeve 21 is firmly fixed to the housing 20.

[0047] After fixing the sleeve 21 to the housing 20 in this way, the pre-assembled valve assembly 41 is inserted inwardly of the collar 19 attached to the inner tube 7 in the outer tube 1 and the housing 20. Further, while fitting the mold coil 42 onto the outer periphery of the cylindrical body 41f of the valve assembly 41, the mold coil 42 is housed in the sleeve 21, and the coupler 42d is stored in the lead-out hole 21c. Seal rings 30 and 31 are provided between the fixed iron core 41e of the valve assembly 41 and the housing 20, between the outer periphery of the fixed iron core 41e, the outer periphery of the mold coil 42, and the inner periphery of the sleeve 21, respectively, to prevent leakage of liquid from inside the shock absorber D.

[0048] Subsequently, a disc-shaped cap 22 is inserted into the thin-walled cap attachment portion 21b at the right end of the sleeve 21 in FIG. 2, and the cap attachment portion 21b is clamped from the outer peripheral side to fix the cap 22 to the sleeve 21. A seal ring 33 is provided between the outer periphery of the cylindrical body 41f, the inner periphery of the mold coil 42, and the cap 22, preventing intrusion of water, dust, etc. from the lead-out hole 21c into the solenoid S.

[0049] When the cap 22 is fixed to the sleeve 21, the damping valve 4 is housed in the housing 20 and the sleeve 21 and is fixed to the housing 20 and the sleeve 21 so as not to fall off.

[0050] Note that the coupler 42d of the mold coil 42 housed in the sleeve 21 is led out of the sleeve 21 from the lead-out hole 21c of the sleeve 21, but the orientation of the coupler 42d may be changed according to the specifications required for the shock absorber D. Therefore, when performing the caulking process for fixing the sleeve 21 to the housing 20, the lead-out hole 21c is positioned in accordance with the orientation of the coupler 42d of the mold coil 42 required by the specifications, and the sleeve 21 is fitted to the housing 20, and the caulking process of the sleeve 21 is performed. The orientation of the lead-out hole 21c of the sleeve 21 can be freely and easily adjusted to any angle in the circumferential direction of the housing 20 when fitting the sleeve 21 onto the outer periphery of the housing 20. Therefore, the sleeve 21 can be easily joined to the housing 20 according to the orientation required for the coupler 42d.

[0051] In this embodiment, the molded coil 42 is equipped with a coupler 42d, but if the coil 42a is equipped with wiring that connects to it without a coupler 42d, the wiring can be housed in the outlet hole 21c.

[0052] Thus, the valve assembly 41 is housed in the housing 20 by inserting the fitting portion 41b into the collar 19 and fitting the fixed iron core 41e to the inner circumference of the housing 20. However, since the fitting portion 41b has inclined surfaces 41b3 and 41b4 on the outer circumferential surface 41b1 facing the collar 19, with the seal ring 50 in between, there is play that allows for a larger swivel motion relative to the collar 19 compared to conventional shock absorbers. Therefore, because the valve assembly 41 is allowed to swivel relative to the collar 19, the valve assembly 41 can be housed in the housing 20 without difficulty even if the axis of the housing 20 is slightly tilted with respect to the axis of the collar 19, and the valve assembly 41 can be easily assembled to the housing 20 and the collar 19.

[0053] Next, we will explain the operation of the shock absorber D, which is configured as described above. First, we will explain the case when the shock absorber D is extended. When the piston 6 moves upward relative to the cylinder 5 in Figure 1, and the shock absorber D is in the extension stroke, the extension chamber R1 is compressed and the compression chamber R2 is expanded. The liquid in the extension chamber R1 moves through the extension damping passage 6a to the compression chamber R2, and since the extension damping passage 6a resists the flow of the liquid, the pressure in the extension chamber R1 becomes higher than the pressure in the compression chamber R2, and the shock absorber D generates an extension damping force that hinders the extension operation.

[0054] Here, by adjusting the amount of current supplied to coil 42a, if the opening pressure of damping valve 4 is lowered, the liquid in the extension chamber R1 will preferentially pass through damping passage 3 rather than extension damping passage 6a to move to reservoir R, and any insufficient liquid in the compression chamber R2 will be supplied from reservoir R to compression chamber R2 through suction passage 8b. Therefore, lowering the opening pressure of damping valve 4 reduces the pressure difference between the extension chamber R1 and the compression chamber R2, thus reducing the extension damping force generated by buffer D. Conversely, by adjusting the amount of current supplied to coil 42a, if the opening pressure of damping valve 4 is increased, the liquid in the extension chamber R1 will pass through extension damping passage 6a to move to compression chamber R2, but it will have difficulty passing through damping passage 3, and the pressure difference between the extension chamber R1 and the compression chamber R2 will increase. Therefore, increasing the opening pressure of the damping valve 4 increases the difference between the pressure in the extension chamber R1 and the pressure in the compression chamber R2, thereby increasing the extension damping force generated by the buffer D.

[0055] Next, we will explain the case when the shock absorber D contracts. When the piston 6 moves downward relative to the cylinder 5 in Figure 1, and the shock absorber D is in the contraction stroke, the compression chamber R2 is compressed and the extension chamber R1 is expanded. The liquid in the compression chamber R2 moves to the reservoir R through the compression damping passage 8a, and the compression damping passage 8a resists the flow of the liquid, while liquid is supplied from the compression chamber R2 to the extension chamber R1, whose volume is expanded by the contraction of the shock absorber D, through the compression passage 6b. As a result, the pressure in the extension chamber R1 and the pressure in the compression chamber R2 become almost equal and both rise, and the shock absorber D generates a compression damping force that hinders the contraction operation.

[0056] Here, by adjusting the amount of current supplied to coil 42a, if the opening pressure of damping valve 4 is lowered, damping valve 4 opens and connects the extension chamber R1 to reservoir R, thus lowering the pressure inside cylinder 5 and reducing the compression damping force generated by buffer D. Conversely, by adjusting the amount of current supplied to coil 42a, if the opening pressure of damping valve 4 is increased, it becomes more difficult for the liquid to pass through damping passage 3, and the pressure inside cylinder 5 increases. Therefore, if the opening pressure of damping valve 4 is increased, both the pressure in the extension chamber R1 and the pressure in the compression chamber R2 increase, and the compression damping force generated by buffer D increases.

[0057] In this manner, the shock absorber D generates a damping force when the rod 2 moves axially relative to the outer tube 1, by the damping valve 4 providing resistance to the liquid flowing through the damping passage 3.

[0058] As described above, the shock absorber D of this embodiment comprises an inner tube 7 having an opening 7a on its side, a tubular collar 19 that abuts against the outer circumference of the inner tube 7 and surrounds the opening 7a, an outer tube 1 that covers the outer circumference of the inner tube 7 and has a through hole 1a radially opposite to the collar 19, a tubular housing 20 that is attached to the outer circumference of the outer tube 1 and surrounds the through hole 1a, a valve assembly 41 housed in the housing 20 and having a fitting portion 41b that fits onto the inner circumference of the collar 19, and a seal ring 50 that is mounted on the fitting portion 41b and is in close contact with the collar 19. The annular outer surface (opposing surface) 41b1 of the fitting portion 41b that faces the collar 19 has inclined surfaces 41b3 and 41b4 on both sides of the seal ring 50, which move away from the annular inner surface (opposing surface) 19a of the collar 19 as they move axially away from the seal ring 50.

[0059] With the shock absorber D configured in this way, the outer peripheral surface 41b1 has inclined surfaces 41b3 and 41b4 on both sides of the seal ring 50 as opposing surfaces of the fitting portion 41b. This allows for play that permits the valve assembly 41 to swivel relative to the collar 19 in the range until the inner peripheral surface 19a contacts the inclined surfaces 41b4 and 41b4. Even if the axis of the housing 20 is slightly tilted relative to the axis of the collar 19, the valve assembly 41 can be easily housed in the housing 20, and the valve assembly 41 can be easily assembled to the housing 20 and collar 19. Therefore, with the shock absorber D configured in this way, even if there are errors in the arrangement or dimensions of the collar 19 and the housing 20, the valve assembly 41 can be assembled to the housing 20 and collar 19. This reduces the requirement for dimensional accuracy for the inner tube 7, outer tube 1, collar 19, and housing 20 compared to conventional designs, and reduces manufacturing costs.

[0060] Furthermore, in the buffer D of this embodiment, the seal ring 50 is an O-ring. With the buffer D configured in this way, since the seal ring 50 is an O-ring, the shape of the outer circumference of the fitting portion 41b including the seal ring 50 is approximately spindle-shaped. Therefore, with the buffer D configured in this way, even if the valve assembly 41 is fitted to the collar 19 at an angle, the seal ring 50 adheres tightly to the inner circumferential surface 19a of the collar 19, and a tight seal can be made between the fitting portion 41b and the collar 19. As a result, sealing performance can be ensured even if the inclination angle of the valve assembly 41 with respect to the collar 19 is large, the requirement for dimensional accuracy is further reduced, and manufacturing costs can be further reduced.

[0061] Furthermore, in the shock absorber D of this embodiment, the valve assembly 41 is fitted into the housing 20 and positioned radially. With the shock absorber D configured in this way, although the fitting portion 41b of the valve assembly 41 has play in the pivoting direction relative to the collar 19, the valve assembly 41 is fitted into the housing 20 and positioned radially. Therefore, when the valve assembly 41 is housed in the housing 20, the valve assembly 41 can be fixed to the collar 19 and the housing 20 without rattling, and there is no need to worry about rattling during use of the shock absorber D causing the damping force generated by the shock absorber D to become unstable.

[0062] In the above description, an annular groove 41b2 is provided in the fitting portion 41b of the valve assembly 41 and the seal ring 50 is mounted therein. However, the valve assembly 41 and collar 19 of the first modified example buffer shown in Figure 4 may be configured as follows. Specifically, an annular groove 19a4 is provided on the inner circumference of the collar 19 and the seal ring 50 is mounted therein. In addition, inclined surfaces 41b3 and 41b4 may be provided on the left and right sides in Figure 4, which are on the axial direction, flanking the seal ring opposing surface 41b5 on the outer circumference 41b1 of the valve assembly 41 that faces the seal ring 50 mounted on the collar 19. These inclined surfaces move away from the inner circumference 19a of the collar 19 as they move away from the seal ring opposing surface 41b5. The inner diameter of the seal ring 50 is smaller than the inner diameter of the inner circumference 19a which faces the collar 19, and is smaller than the outer diameter of the seal ring opposing surface 41b5.

[0063] In the first modified shock absorber, a seal ring 50 is attached to the collar 19, and instead of eliminating the annular groove 41b2 on the outer circumference of the fitting portion 41b, a seal ring opposing surface 41b5 is provided on the outer circumference surface 41b1, which has the largest outer diameter and faces the seal ring 50. When the valve assembly 41 configured in this way is fitted into the collar 19, the seal ring 50 attached to the collar 19 makes close contact with the seal ring opposing surface 41b5 of the fitting portion 41b, sealing the space between the collar 19 and the fitting portion 41b. Furthermore, since the fitting portion 41b has inclined surfaces 41b3 and 41b4 on both sides in the axial direction of the seal ring opposing surface 41b5, it is possible to pivot relative to the collar 19, and the fitting portion 41b can be fitted in an inclined position with respect to the axis of the collar 19.

[0064] Therefore, even if the seal ring 50 is attached to the collar 19 instead of the outer circumference of the fitting portion 41b, and the outer circumference 41b1 that serves as the opposing surface of the fitting portion 41b has a seal ring opposing surface 41b5 with the largest outer diameter, and inclined surfaces 41b3 and 41b4 are provided on both sides in the axial direction of the seal ring opposing surface 41b5, the further they are from the seal ring opposing surface 41b5, the further they are from the inner circumference (opposing surface) 19a of the collar 19, there is still enough play to allow the valve assembly 41 to swivel relative to the collar 19 in the range until the inner circumference 19a contacts the inclined surfaces 41b3 and 41b4, and even if the axis of the housing 20 is slightly tilted with respect to the axis of the collar 19, the valve assembly 41 can be easily housed in the housing 20, and the valve assembly 41 can be easily assembled to the housing 20 and the collar 19. Therefore, with the shock absorber of the first modified example configured in this way, even if there is an error in the arrangement of the collar 19 and the housing 20, the valve assembly 41 can be assembled to the housing 20 and the collar 19. As a result, the dimensional accuracy requirements for the inner tube 7, outer tube 1, collar 19 and housing 20 are lower than in the conventional method, and manufacturing costs can be reduced.

[0065] Furthermore, the valve assembly 41 and collar 19 may be configured as in the second modified shock absorber shown in Figure 5. Specifically, the valve assembly 41 of the second modified shock absorber eliminates the inclined surfaces 41b3 and 41b4 from the structure of the fitting portion 41b of the valve assembly 41 shown in Figure 2, and has a structure in which the outer diameter of the outer peripheral surface 41b1 is constant as the opposing surface of the fitting portion 41b. The collar 19 has a structure in which inclined surfaces 19a2 and 19a3 are provided on the left and right sides in Figure 5, which are on the axial direction, sandwiching the seal ring opposing surface 19a1 that faces the seal ring 50 on the inner peripheral surface 19a, and the further they are from the seal ring opposing surface 19a1, the further they are from the outer peripheral surface 41b1 of the fitting portion 41b. The outer diameter of the seal ring 50 is larger than the outer diameter of the outer peripheral surface 41b1 that faces the fitting portion 41b, and is larger than the inner diameter of the seal ring opposing surface 19a1.

[0066] In the second modified buffer, the seal ring opposing surface 19a1 on the inner circumferential surface 19a of the collar 19 has the smallest inner diameter, and inclined surfaces 19a2 and 19a3 are provided on both sides in the axial direction of the seal ring opposing surface 19a1 of the collar 19, so that the inner diameter on both sides in the axial direction of the inner circumferential surface 19a gradually increases towards the end.

[0067] When the valve assembly 41 configured in this way is fitted into the collar 19, the seal ring 50 mounted on the fitting portion 41b comes into close contact with the seal ring opposing surface 19a1 of the collar 19, sealing the space between the collar 19 and the fitting portion 41b. Furthermore, since the collar 19 has inclined surfaces 19a2 and 19a3 on both sides in the axial direction of the seal ring opposing surface 19a1, it is possible to pivot relative to the collar 19, and the fitting portion 41b can be fitted in an inclined position with respect to the axis of the collar 19.

[0068] Therefore, even if the seal ring opposing surface 19a1 and the inclined surfaces 19a2 and 19a3 are provided on the inner circumference of the collar 19 rather than the outer circumference of the fitting portion 41b, on both sides of the seal ring opposing surface 19a1 in the axial direction, the further they are from the seal ring opposing surface 19a1, the more play is created that allows the valve assembly 41 to swivel relative to the collar 19 in the range until the outer circumference 41b1 contacts the inclined surfaces 19a2 and 19a3. This allows the valve assembly 41 to be housed in the housing 20 without difficulty, even if the axis of the housing 20 is slightly tilted with respect to the axis of the collar 19, and the valve assembly 41 can be easily assembled to the housing 20 and the collar 19. Therefore, with the second modified shock absorber configured in this way, even if there is an error in the arrangement of the collar 19 and the housing 20, the valve assembly 41 can be assembled to the housing 20 and the collar 19. As a result, the dimensional accuracy requirements for the inner tube 7, outer tube 1, collar 19 and housing 20 are lower than in the conventional design, and manufacturing costs can be reduced.

[0069] Furthermore, the valve assembly 41 and collar 19 may be configured as in the third modified shock absorber shown in Figure 6. Specifically, the valve assembly 41 of the third modified shock absorber has the annular groove eliminated from the structure of the fitting portion 41b of the valve assembly 41 shown in Figure 5, and has a structure in which the outer diameter of the outer peripheral surface 41b1 is constant as the opposing surface of the fitting portion 41b. The collar 19 has an annular groove 19a4 on its inner circumference into which the seal ring 50 is mounted, and has an inclined surface 19a2, 19a3 on both sides in the axial direction of the inner peripheral surface 19a, which is the left and right sides in Figure 6, where the seal ring 50 is sandwiched between the inner peripheral surface 19a, and moves away from the outer peripheral surface 41b1 of the fitting portion 41b as it moves away from the seal ring 50. Note that the inner diameter of the seal ring 50 is smaller than the inner diameter of the inner peripheral surface 19a as the opposing surface of the collar 19, and is smaller than the outer diameter of the outer peripheral surface 41b1 as the opposing surface of the fitting portion 41b.

[0070] In the third modified shock absorber, the inner diameter of the seal ring 50 is smaller than the smallest inner diameter of the inner circumferential surface 19a of the collar 19, and inclined surfaces 19a2 and 19a3 are provided on both sides of the axial direction of the seal ring 50 of the collar 19, so that the inner diameter of both sides of the inner circumferential surface 19a in the axial direction gradually increases towards the end.

[0071] When the valve assembly 41 configured in this way is fitted into the collar 19, the seal ring 50 attached to the collar 19 comes into close contact with the outer circumferential surface 41b1 of the fitting portion 41b, thereby sealing the space between the collar 19 and the fitting portion 41b. Furthermore, since the inner circumferential surface 19a of the collar 19 has inclined surfaces 19a2 and 19a3 on both sides in the axial direction of the seal ring 50, the valve assembly 41 can pivot relative to the collar 19, and the fitting portion 41b can be fitted in an inclined position with respect to the axis of the collar 19.

[0072] Therefore, even if a seal ring 50 is attached to the inner circumference of the collar 19, and inclined surfaces 19a2 and 19a3 are provided on both sides of the inner circumferential surface 19a of the collar 19 in the axial direction of the seal ring 50, the further they are from the seal ring 50, the further they are from the outer circumferential surface 41b1 of the fitting portion 41b, there is still enough play to allow the valve assembly 41 to swivel relative to the collar 19 until the outer circumferential surface 41b1 contacts the inclined surfaces 19a2 and 19a3. This allows the valve assembly 41 to be easily housed in the housing 20 even if the axis of the housing 20 is slightly tilted relative to the axis of the collar 19, and the valve assembly 41 can be easily assembled to the housing 20 and the collar 19. Therefore, with the third modified shock absorber configured in this way, even if there is an error in the arrangement of the collar 19 and the housing 20, the valve assembly 41 can be assembled to the housing 20 and the collar 19. As a result, the dimensional accuracy requirements for the inner tube 7, outer tube 1, collar 19 and housing 20 are lower than in the conventional method, and manufacturing costs can be reduced.

[0073] As can be understood from the above, by providing an inclined surface on either the inner circumferential surface 19a or the outer circumferential surface 41b1, which are opposing surfaces of the fitting portion 41b of the collar 19 and the valve assembly 41, and by attaching a seal ring to one of them and providing a seal ring opposing surface on the other, it is possible to fit the valve assembly 41 to the collar 19 in an inclined position while sealing the space between the collar 19 and the fitting portion 41b. This reduces the dimensional accuracy requirements for the collar 19 and the housing 20 compared to conventional designs, and thus reduces manufacturing costs.

[0074] Furthermore, as described above, the fitting portion 41b of the valve assembly 41 is fitted to the inner circumference of the collar 19. However, as shown in Figure 7, the fitting portion 41b of the valve assembly 41 may be cylindrical, and the fitting portion may be fitted to the outer circumference of the collar 19. In this case, as shown in Figures 7(a) to (d), the outer circumferential surface 19b of the collar 19 is used as the opposing surface, and the inner circumferential surface 41b11 of the fitting portion 41b is used as the opposing surface. Inclined surfaces 19b3, 19b4, 41b31, and 41b41 are provided on either the outer circumferential surface 19b or the inner circumferential surface 41b11, and a seal ring 50 is attached to one of them. The other side of the seal ring may be provided with seal ring opposing surfaces 19b2 and 41b51. By doing so, a seal can be maintained between the collar 19 and the mating portion 41b, and the valve assembly 41 can be fitted to the collar 19 in an inclined position. This reduces the dimensional accuracy requirements for the collar 19 and housing 20 compared to conventional methods, thereby lowering manufacturing costs.

[0075] Furthermore, in the aforementioned shock absorber D, inclined surfaces are provided on both sides of the seal ring 50 or the seal ring facing surface on one of the mutually opposing annular surfaces of the collar 19 and the fitting portion 41b, thereby providing play that allows the valve assembly 41 to swivel relative to the collar 19, and enabling the valve assembly 41 to be easily assembled to the housing 20 and the collar 19. However, the shock absorber may also be configured as in the ninth to twelfth modified examples shown in Figure 8.

[0076] In the shock absorbers of each of the 9th to 12th modifications, one of the annular opposing surfaces of the collar 19 and the fitting portion 41b has an inclined surface on one side in the axial direction of the seal ring 50 or the seal ring opposing surface facing the seal ring, which moves away from the other annular opposing surface of the collar 19 and the fitting portion 41b as it moves axially away from the seal ring 50 or the seal ring opposing surface, and the other of the annular opposing surfaces of the collar 19 and the fitting portion 41b has an inclined surface on the other side in the axial direction of the seal ring 50 or the seal ring opposing surface facing the seal ring 50, which moves away from the one annular opposing surface of the collar 19 and the fitting portion 41b as it moves axially away from the seal ring 50 or the seal ring opposing surface.

[0077] More specifically, in the ninth modified shock absorber, as shown in Figure 8(a), the fitting portion 41b is fitted to the inner circumference of the collar 19, and the outer circumferential surface (opposing surface) 41b1 of the fitting portion 41b has an inclined surface 41b3 only on the left side in the figure, which is one side in the axial direction of the seal ring 50, and does not have an inclined surface on the other side, the right side in the figure, and has a constant outer diameter. The inner circumferential surface (opposing surface) 19a of the collar 19 has an inclined surface 19a3 only on the right side in the figure, which is the other side of the seal ring opposing surface 19a1, and does not have an inclined surface on the one side, the left side in the figure, and has a constant outer diameter. In the shock absorber of the ninth modified example configured in this way, inclined surfaces 41b3 and 19a3 are alternately provided in the axial direction, sandwiching the seal ring 50 or the seal ring opposing surface 19a1. This creates play that allows the valve assembly 41 to pivot relative to the collar 19, so that the valve assembly 41 can be easily assembled to the housing 20 and the collar 19. This reduces the dimensional accuracy requirements for the collar 19 and the housing 20 compared to conventional designs, and thus reduces manufacturing costs.

[0078] In the 10th modified shock absorber, as shown in Figure 8(b), the fitting portion 41b is fitted to the inner circumference of the collar 19. The outer circumferential surface (opposing surface) 41b1 of the fitting portion 41b has an inclined surface 41b4 only on the right side in the figure, which is the other side in the axial direction of the seal ring 50, and does not have an inclined surface on the left side in the figure, which is the other side, and has a constant outer diameter. The inner circumferential surface (opposing surface) 19a of the collar 19 has an inclined surface 19a2 only on the left side in the figure, which is the other side of the seal ring opposing surface 19a1, and does not have an inclined surface on the right side in the figure, and has a constant outer diameter. In the shock absorber of the tenth modified example configured in this way, inclined surfaces 41b4 and 19a2 are alternately provided in the axial direction, sandwiching the seal ring 50 or the seal ring opposing surface 19a1. This creates play that allows the valve assembly 41 to pivot relative to the collar 19, so that the valve assembly 41 can be easily assembled to the housing 20 and the collar 19. This reduces the dimensional accuracy requirements for the collar 19 and the housing 20 compared to conventional designs, and thus reduces manufacturing costs.

[0079] Furthermore, in the 11th modified buffer, as shown in Figure 8(c), the collar 19 is fitted to the inner circumference of the fitting portion 41b. The inner circumferential surface (opposing surface) 41b11 of the fitting portion 41b has an inclined surface 41b31 only on the left side in the figure, which is one side in the axial direction of the seal ring 50, and an inclined surface on the right side in the figure, which is the other side, and has a constant outer diameter. The outer circumferential surface (opposing surface) 19b of the collar 19 has an inclined surface 19b4 only on the right side in the figure, which is the other side of the seal ring opposing surface 19b2, and does not have an inclined surface on the left side in the figure, which is one side, and has a constant outer diameter. In the shock absorber of the 11th modified example configured in this way, inclined surfaces 41b31 and 19b4 are alternately provided in the axial direction, sandwiching the seal ring 50 or the seal ring opposing surface 19b2. This creates play that allows the valve assembly 41 to pivot relative to the collar 19, so that the valve assembly 41 can be easily assembled to the housing 20 and the collar 19. This reduces the dimensional accuracy requirements for the collar 19 and the housing 20 compared to conventional designs, and thus reduces manufacturing costs.

[0080] Furthermore, in the 12th modified buffer, as shown in Figure 8(d), the collar 19 is fitted to the inner circumference of the fitting portion 41b. The inner circumferential surface (opposing surface) 41b11 of the fitting portion 41b has an inclined surface 41b41 only on the right side in the figure, which is the other axial side of the seal ring 50, and an inclined surface on the left side in the figure, which is the other side, and has a constant outer diameter. The outer circumferential surface (opposing surface) 19b of the collar 19 has an inclined surface 19b3 only on the left side in the figure, which is the other side of the seal ring opposing surface 19b2, and does not have an inclined surface on the right side in the figure, and has a constant outer diameter. In the shock absorber of the 12th modified example configured in this way, inclined surfaces 41b41 and 19b3 are alternately provided in the axial direction, sandwiching the seal ring 50 or the seal ring opposing surface 19b2. This creates play that allows the valve assembly 41 to pivot relative to the collar 19, so that the valve assembly 41 can be easily assembled to the housing 20 and the collar 19. This reduces the dimensional accuracy requirements for the collar 19 and the housing 20 compared to conventional designs, and thus reduces manufacturing costs.

[0081] As described above, according to the shock absorbers in the ninth to twelfth modifications, the valve assembly 41 can be fitted to the collar 19 in an inclined position while sealing between the collar 19 and the fitting portion 41b, the dimensional accuracy requirements for the collar 19 and housing 20 are lower than in the conventional design, and manufacturing costs can be reduced. In the ninth to twelfth modifications, the seal ring 50 may be attached to either the collar 19 or the fitting portion 41b. Although preferred embodiments of the present invention have been described in detail above, modifications, alterations, and changes are possible as long as they do not deviate from the scope of the claims.

[0082] 1...Outer tube, 1a...Through hole, 7...Inner tube, 7a...Opening, 19...Collar, 19a...Inner circumferential surface (opposing surface), 19a1...Seal ring opposing surface, 19a2, 19a3, 19b3, 19b4, 41b3, 41b4, 41b31, 41b41...Inclined surface, 19b...Outer circumferential surface (opposing surface), 20...Housing, 41...Valve assembly, 41b...Matching part, 41b1...Outer circumferential surface (opposing surface), 41b11...Inner circumferential surface (opposing surface), 50...Seal ring, D...Battery

Claims

1. A shock absorber comprising: an inner tube having an opening on its side; a tubular collar that abuts against the outer circumference of the inner tube and surrounds the opening; an outer tube that covers the outer circumference of the inner tube and has a through hole radially opposite to the collar; a tubular housing that is attached to the outer circumference of the outer tube and surrounds the through hole; a valve assembly housed in the housing and having a fitting portion that fits onto the inner or outer circumference of the collar; and a seal ring that is attached to one of the collar and the fitting portion and is in close contact with the other of the collar and the fitting portion, wherein one of the annular opposing surfaces of the collar and the fitting portion that face each other has inclined surfaces on both sides of the seal ring or the seal ring opposing surface that face the seal ring, such that the distance from the other annular opposing surface of the collar and the fitting portion increases as it moves axially away from the seal ring or the seal ring opposing portion.

2. A shock absorber comprising: an inner tube having an opening on its side; a tubular collar that abuts against the outer circumference of the inner tube and surrounds the opening; an outer tube that covers the outer circumference of the inner tube and has a through hole radially opposite to the collar; a tubular housing that is attached to the outer circumference of the outer tube and surrounds the through hole; a valve assembly housed within the housing and having a fitting portion that fits onto the inner or outer circumference of the collar; and a seal ring that is attached to one of the collar and the fitting portion and is in close contact with the other of the collar and the fitting portion, wherein one of the annular opposing surfaces of the collar and the fitting portion that face each other has an inclined surface that moves away from the other annular opposing surface of the collar and the fitting portion as it moves axially away from the seal ring or the seal ring opposing surface facing the seal ring, A buffer having an inclined surface on the other of the annular opposing surfaces of the collar and the fitting portion that are opposite to each other, such that the inclined surface moves away from one of the annular opposing surfaces of the collar and the fitting portion as it moves axially away from the seal ring or the seal ring opposing portion on the other side in the axial direction from the seal ring or the seal ring opposing portion.

3. A shock absorber according to claim 1, wherein the seal ring is an O-ring.

4. A shock absorber according to claim 1, wherein the valve assembly is a shock absorber that is fitted into the housing and positioned radially.

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