Shock absorber

Abstract

This shock absorber (D) is provided with: a cylinder (1); a piston rod (2); a piston (3) that divides the inside of the cylinder (1) into an extension-side chamber (R1) and a compression-side chamber (R2); a bypass passage (40) that is provided to the piston rod (2) and bypasses the extension-side damping valve (7) and the compression-side damping valve (8); a damping force regulating valve (41) provided in the bypass passage (40); a sub-cylinder (4) housed in a compression-side chamber (R2) in the cylinder (1) to form a hydraulic lock chamber (L) and a compensation chamber (R); a lock plate (31) inserted into the hydraulic lock chamber (L); the sealing body (6) is arranged at the front end of the piston rod (2); the compensation chamber (R) has a gas chamber (G) and a liquid chamber (A) that communicates with the compression-side chamber (R2), the bypass passage (40) is formed by including a vertical hole (2d) that opens from the tip of the piston rod (2), and the closing body (6) closes the opening of the vertical hole (2d) of the piston rod (2).

Description

TECHNICAL FIELD

[0001] The present application relates to a damper. BACKGROUND

[0002] For example, as disclosed in JP2019-215040A, a damper is provided with: a cylinder; a piston rod movably inserted into the cylinder; a piston coupled to the piston rod and movably inserted into the cylinder, and dividing the cylinder into an extension-side chamber filled with hydraulic oil and a compression-side chamber; a piston rod movably inserted into the cylinder and coupled to the piston; a free piston axially movably inserted into the cylinder and forming a gas chamber opposite the compression-side chamber in the cylinder; an extension-side spool valve opening and closing an extension-side passage provided in the piston; and a compression-side spool valve opening and closing a compression-side passage provided in the piston; which is installed between a vehicle body and a rear wheel of a suspension straddle vehicle, and generates a damping force that suppresses vibration of the vehicle body at the time of extension and contraction.

[0003] In addition, the conventional damper is provided with: a bypass passage that opens from the front end of the piston rod facing the compression-side chamber, passes through the extension-side chamber while bypassing the extension-side passage and the compression-side passage, and is provided in order to be able to adjust the damping force generated at the time of extension and contraction; and a needle valve provided in the bypass passage and capable of adjusting the flow path area. PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0004] Patent Document 1: JP2019-215040A SUMMARY PROBLEMS TO BE SOLVED BY THE INVENTION

[0005] In the conventional damper, when a contraction operation in which the piston moves in a direction in which the compression-side chamber is compressed with respect to the cylinder is performed, the compression-side spool valve that opens and closes the compression-side passage provided in the piston is opened, and hydraulic oil moves from the compression-side chamber to the extension-side chamber, so a pressure difference is generated between the pressure of the compression-side chamber and the pressure of the extension-side chamber, and a compression-side damping force that suppresses the contraction operation can be generated.

[0006] In such a conventional damper, the compression-side damping force can be generated and the vibration of the vehicle body can be suppressed, but when it is necessary to travel on a rough road in a region where road maintenance is not perfect or the like, a larger compression-side damping force than before is sometimes required to be generated to the damper when the damper is contracted to the vicinity of the stroke end.

[0007] To meet this requirement, the pressure in the compression chamber could simply be increased during the buffer's retraction. However, in conventional buffer designs, the gas chamber is positioned opposite the compression chamber via a free piston, making it impossible to raise the pressure in the compression chamber above that of the gas chamber. Therefore, even attempts to increase the damping force on the compression side are limited. Furthermore, the needle valve opening is typically adjusted manually by the user, but in conventional buffers, it's not possible to increase the damping force on the compression side simply at the end of the retraction stroke.

[0008] The purpose of this invention is to provide a buffer that can both adjust the damping force and generate a large damping force near the end of the stroke. Problem-solving methods

[0009] To address the aforementioned issues, the buffer of the present invention comprises: a cylinder; a piston rod axially movable and inserted into the cylinder; a piston connected to the piston rod and axially movable and inserted into the cylinder, dividing the cylinder into an extension-side chamber and a compression-side chamber; an extension-side damping valve that applies resistance to fluid flow from the extension-side chamber to the compression-side chamber; a compression-side damping valve that applies resistance to fluid flow from the compression-side chamber to the extension-side chamber; a bypass passage disposed on the piston rod and bypassing the extension-side damping valve and the compression-side damping valve to connect the extension-side chamber and the compression-side chamber; a damping force regulating valve disposed in the bypass passage; and a secondary cylinder housed within the cylinder. The cylinder includes a compression chamber; a partition wall dividing the auxiliary cylinder into a compensation chamber opposite to the piston, which is a hydraulic lock chamber; a locking plate having a hole and axially movable, which can be inserted into the auxiliary cylinder and the hydraulic lock chamber; and a sealing body located at the front end of the piston rod, which closes the hole when it abuts against the locking plate; the compensation chamber has a gas chamber and a liquid chamber communicating with the compression chamber; the bypass passage is formed by including a vertical hole opening from the front end of the piston rod, a first transverse hole opening from the side of the piston rod to communicate the compression chamber with the vertical hole, and a second transverse hole opening from the side of the piston rod to communicate the elongation chamber with the vertical hole; and the sealing body closes the opening of the vertical hole of the piston rod.

[0010] In a buffer constructed in this manner, when a contraction action occurs, the piston rod moves in the contraction direction and the closed body abuts against the locking plate. The hole of the locking plate is closed by the closed body, and the locking plate is pushed into the hydraulic locking chamber. As a result, the pressure in the hydraulic locking chamber rises, which can add the resistance that inhibits the movement of the piston rod to the damping force during the contraction action. Attached Figure Description

[0011] Figure 1 This is a cross-sectional view of the buffer in one embodiment. Implementation

[0012] The present invention will be described based on the embodiments shown in the figures. Figure 1As shown, in one embodiment, the buffer D includes: a cylinder 1; a piston rod 2, which is axially movable and inserted into the cylinder 1; a piston 3, which is connected to the piston rod 2 and axially movable and inserted into the cylinder 1, dividing the cylinder 1 into an extension-side chamber R1 and a compression-side chamber R2; an extension-side vane valve 7, which acts as an extension-side damping valve, applies resistance to the fluid flow from the extension-side chamber R1 to the compression-side chamber R2; a compression-side vane valve 8, which acts as a compression-side damping valve, applies resistance to the fluid flow from the compression-side chamber R2 to the extension-side chamber R1; and a bypass passage 40 provided on the piston rod. 2. The extended side chamber R1 and the compression side chamber R2 are connected by bypassing the extended side vane valve 7 and the compression side vane valve 8; a needle valve 41, which serves as a damping force regulating valve, is provided in the bypass passage 40; an auxiliary cylinder 4 is housed in the compression side chamber R2 within the cylinder 1; a partition wall 4a1 divides the auxiliary cylinder 4 into a hydraulic lock chamber L and a compensation chamber R opposite to the piston of the hydraulic lock chamber L; a locking plate 31 is axially movable and inserted into the hydraulic lock chamber L; a spring 32 is installed between the locking plate 31 and the partition wall 4a1 to apply force to the locking plate 31 towards the piston side; and a sealing body 6 is provided at the front end of the piston rod 2. Although not shown, the damper D is, for example, installed between the body and the rear wheel in a suspension straddle-type vehicle such as a motorcycle, generating a damping force during extension and retraction to suppress body vibration. In addition, the damper D can be used in vehicles other than suspension straddle-type vehicles, and can also be used in equipment or buildings other than vehicles.

[0013] The following describes the various parts of the buffer D. Cylinder 1 is cylindrical, and its upper opening is mounted on... Figure 1 The upper part of the cover 10 is closed. The cover 10 has a bracket 10a that closes the upper opening of the cylinder 1 and can be connected to the body of the suspension straddle-type vehicle. Additionally, in the cylinder 1... Figure 1 The lower inner circumference is fitted with an annular guide 11 that passes through the piston rod 2, in the cylinder 1. Figure 1 At the lower end of the opening, an annular protrusion stop 12 is installed. The guide 11 restricts the movement from the inside to the outside of the cylinder 1 by the stop ring 13 installed on the inner circumference of the cylinder 1. Figure 1 It moves downwards and is pushed by the pressure of the liquid inside cylinder 1. Figure 1 The lower part is pressed and positioned to abut against the stop ring 13. In addition, a cylindrical bushing 14 that slides in contact with the outer circumference of the piston rod 2 and a sealing ring 15 that slides in contact with the outer circumference of the piston rod 2 to seal the outer circumference of the piston rod 2 are installed on the inner circumference of the guide member 11. A sealing ring 16 that closely contacts the inner circumference of the cylinder 1 to seal the space between the cylinder 1 and the guide member 11 is installed on the outer circumference of the guide member 11.

[0014] Additionally, in cylinder 1 Figure 1 An annular upper spring bracket 25 is screwed and fixed to the outer periphery of the upper part of the cylinder 1. When the cylinder 1 is rotated, the upper spring bracket 25 can move axially relative to the cylinder 1.Figure 1 Displacement in the vertical direction.

[0015] The piston rod 2 is axially movable into the cylinder 1 via the inner circumference of the protrusion stop 12 and the guide 11, and its front end is connected to a piston 3, which is also axially movable into the cylinder 1. The piston rod 2 includes: a small-diameter portion 2a, provided at the front end... Figure 1 A piston 3 is mounted on the upper part and the outer periphery; a threaded portion 2b is provided on the outer periphery of the upper end of the small diameter portion 2a; a stepped portion 2c is formed between the small diameter portion 2a and a portion lower than the small diameter portion 2a; a vertical hole 2d opens from the front end and leads to the base end; a first transverse hole 2e opens from the side of the small diameter portion 2a and leads to the vertical hole 2d; and a second transverse hole 2f opens from a portion lower than the stepped portion 2c and leads to the vertical hole 2d.

[0016] In the buffer D of this embodiment, the piston rod 2 is cylindrical by having a vertical hole 2d along its entire length. In addition, a cylindrical valve seat component 42 is installed on the upper side of the vertical hole 2d of the piston rod 2, slightly above the opening of the second horizontal hole 2f.

[0017] Additionally, in piston rod 2 Figure 1 At the lower end, a bracket 17 is installed to connect the piston rod 2 to the swing arm of the rear wheel of a straddle-type vehicle with an external suspension. A collision buffer rubber 18, mounted on top of the bracket 17, is fitted around the lower periphery of the piston rod 2. The collision buffer rubber 18 is mounted on the cylinder 1... Figure 1 The lower and middle protrusions 12 are axially opposed. When the buffer D travels to the near end of its travel on the contraction side, it comes into contact with the protrusions 12 and is compressed. This compresses the buffer D and exerts a spring force to suppress further travel of the buffer D in the contraction direction, thus mitigating the impact when the buffer D is fully contracted.

[0018] The bracket 17 has a lower spring support 17a on its outer periphery, and a suspension spring 26, which is a coil spring, is installed between the lower spring support 17a and the upper spring support 25 mounted on the outer periphery of the cylinder 1. The suspension spring 26 applies force in the direction that separates the cylinder 1 and the piston rod 2 axially, that is, in the direction that extends the buffer D. When the buffer D is installed between the body of the suspension straddle-type vehicle and the rear wheel, it exerts a spring force to elastically support the body. In addition, since the position of the upper spring support 25 relative to the cylinder 1 can be changed axially, the initial load applied to the suspension spring 26 can be changed to adjust the vehicle height of the suspension straddle-type vehicle.

[0019] A valve stop 9, an annular compression-side vane valve 8, an annular piston 3, an annular extension-side vane valve 7, and a collar 20 are sequentially assembled on the small-diameter portion 2a of the piston rod 2. The compression-side vane valve 8, piston 3, and extension-side vane valve 7 are clamped and fixed to the small-diameter portion 2a of the piston rod 2 by a piston nut 27 screwed onto the threaded portion 2b at the front end of the small-diameter portion 2a and the stepped portion 2c of the piston rod 2.

[0020] The piston 3 has piston rings 3a on its outer periphery that slide in contact with the inner periphery of the cylinder 1, dividing the cylinder 1 into an elongation-side chamber R1 filled with liquid and a compression-side chamber R2. Furthermore, the piston 3 has an elongation-side passage 3b and a compression-side passage 3c that connect the elongation-side chamber R1 and the compression-side chamber R2. The liquid filling the elongation-side chamber R1 and the compression-side chamber R2 is, for example, hydraulic oil, but other liquids may also be used.

[0021] The compression-side damping valve 8 is a stacked vane valve formed by stacking multiple annular plates. Its inner circumference is fixed to the piston rod 2, while its outer circumference allows bending and stacking on the piston 3. Figure 1 The lower end of the piston 3. When the compression-side vane valve 8 is deposited on the piston 3, it closes the compression-side passage 3c. When it is bent by the pressure of the compression-side chamber R2, which functions through the compression-side passage 3c, it opens the compression-side passage 3c. When the compression-side vane valve 8 bends significantly, the valve stop 9 abuts against the back of the compression-side vane valve 8, limiting further bending and protecting the compression-side vane valve 8. In addition to the compression-side vane valve 8, the compression-side damping valve can be any valve that can apply resistance to the liquid flow through the compression-side passage 3c. In addition to valves that can open and close the compression-side passage 3c, it can also be a throttling orifice or a choke ring.

[0022] On the other hand, the elongation-side damping valve 7 is a laminated vane valve formed by stacking multiple annular plates. Its inner circumference is fixed to the piston rod 2, while its outer circumference allows bending and stacking on the piston 3. Figure 1 Upper middle section. When the elongated side vane valve 7 is deposited on the piston 3, it closes the elongated side passage 3b. When it is bent by the pressure of the elongated side chamber R1, which functions through the elongated side passage 3b, it opens the elongated side passage 3b. In addition to the elongated side vane valve 7, the elongated side damping valve can be any valve that can apply resistance to the liquid flow through the elongated side passage 3b. In addition to a valve that can open and close the elongated side passage 3b, it can also be a throttling orifice or a choke ring.

[0023] The collar 20 is annular and fits around the outer periphery of the small-diameter portion 2a of the piston rod 2, and has the following characteristics: Figure 1 The enlarged diameter portion 20a on the lower side is larger than the outer diameter of the small diameter portion 2a, and the cutout 20b that radially penetrates the wall of the enlarged diameter portion 20a.

[0024] Furthermore, when the collar 20 is assembled together with the valve stop 9, the compression side vane valve 8, the piston 3 and the extension side vane valve 7 on the small diameter portion 2a of the piston rod 2, the inner circumference of the expanded diameter portion 20a is aligned with the first transverse hole 2e, and the first transverse hole 2e is connected to the compression side chamber R2 via the cut 20b.

[0025] Furthermore, the valve stop 9, compression-side vane valve 8, piston 3, extension-side vane valve 7, and collar 20, which are assembled sequentially from bottom to top on the outer periphery of the small-diameter portion 2a of the piston rod 2, are clamped by the piston nut 27, which is threaded into the threaded portion 2b, and the stepped portion 2c, and thus fixed to the small-diameter portion 2a of the piston rod 2. In this state, with the piston nut 27 fixing the components assembled on the small-diameter portion 2a, starting with the piston 3, to the piston rod 2, the piston nut 27 is threaded into the piston rod 2 at a position spaced further down from the upper end of the piston rod 2 (the front end) towards the side opposite to the auxiliary cylinder.

[0026] Additionally, a sealing body 6 is pressed into the vertical hole 2d in the piston rod 2. The sealing body 6 includes a cylindrical insertion shaft 6a pressed into the vertical hole 2d, and a disc-shaped head 6b with a larger diameter than the insertion shaft 6a on the auxiliary cylinder side of the insertion shaft 6a. When the insertion shaft 6a is pressed into the vertical hole 2d of the piston rod 2 until the head 6b... Figure 1 When the lower end abuts against the front end face of the piston rod 2, the sealing body 6 seals the vertical hole 2d. Figure 1 The upper end of the insertion shaft 6a is positioned within the vertical hole 2d, radially opposite to the piston nut 27, and fixed to the piston rod 2. Therefore, because the insertion shaft 6a in the enclosure 6 expands the outer diameter of the portion of the piston nut 27 threaded into the threaded portion 2b, loosening of the piston nut 27 threaded into the threaded portion 2b is prevented. Thus, the enclosure 6 closes the opening at the upper end of the vertical hole 2d and also prevents the piston nut 27 from loosening. The length of the insertion shaft 6a is set such that it does not close the first transverse hole 2e when the head 6b abuts against the front end of the piston rod 2, but can be radially opposite to the piston nut 27.

[0027] Furthermore, the head 6b in the enclosed body 6 abuts against the upper end of the auxiliary cylinder side end that becomes the piston rod 2, and the lower end face of the head 6b faces the upper end face of the piston nut 27 with a gap, thus not interfering with the piston nut 27. The enclosed body 6's Figure 1 The surface of the upper end face that abuts against the sheet portion 31c of the locking piece 31 is a flat plane at the same level.

[0028] Furthermore, the vertical hole 2d of the piston rod 2 communicates with the elongation side chamber R1 and the compression side chamber R2 through the first horizontal hole 2e and the second horizontal hole 2f. Together with the first horizontal hole 2e and the second horizontal hole 2f, it forms a bypass channel 40 that bypasses the elongation side channel 3b and the compression side channel 3c in the piston 3, which is fixed to the outer periphery of the small diameter portion 2a of the piston rod 2, and connects the elongation side chamber R1 and the compression side chamber R2. In addition, the guide member 11 is provided with a baffle 50 that closes the second horizontal hole 2f when it slides in contact with the side of the piston rod 2 and causes the buffer D to extend until it reaches near the end of its stroke, and an annular buffer pad 51 that abuts against the valve stop block 9. When the buffer D is at its most extended, the baffle 50 closes the bypass channel 40 while blocking the gap inside the buffer pad 51, causing the pressure in the gap to rise, which can suppress further extension of the buffer D.

[0029] Furthermore, the needle valve 41 is axially movable and accommodated within the vertical hole 2d of the piston rod 2, and is positioned closer to the valve seat component 42. Figure 1 The needle valve 41 slides freely into the piston rod 2, in the lower middle. Figure 1 The upper middle part has a conical valve head 41a that can move in and out of the valve seat component 42.

[0030] When the needle valve 41 causes the valve head 41a to sit on the lower inner circumference of the valve seat component 42, it cuts off the bypass passage 40. When the valve head 41a moves away from the valve seat component 42, it opens the bypass passage 40. The size of the flow path area between the needle valve 41 and the valve seat component 42 can be adjusted by moving it away from or closer to the valve seat component 42. Furthermore, the lower end of the needle valve 41, which is the rear end, is conical in shape, protruding downward from the opening of the vertical hole 2d at the base end of the piston rod 2, and protruding into the hole 17b provided inside the bracket 17.

[0031] Additionally, the bracket 17 has a threaded hole 17c that opens from the side and communicates with the hole 17b, with its axis orthogonal to the axis of the needle valve 41. An adjusting bolt 43 with a conical front end that abuts against the rear end of the needle valve 41 is installed in the threaded hole 17c. Therefore, when the adjusting bolt 43 is rotated, causing its front end to move towards the hole 17b, the needle valve 41 is pushed by the front end of the adjusting bolt 43, causing the piston rod 2 to move inward. Figure 1 The valve head 41a moves upwards, thus allowing it to approach the valve seat component 42 and reduce the flow path area. Conversely, when the adjusting bolt 43 is rotated, causing its tip to move out of the hole 17b, the needle valve 41 moves relative to the piston rod 2. Figure 1 The valve head 41a is moved downwards to move away from the valve seat component 42, thereby increasing the flow path area.

[0032] Thus, the needle valve 41 can be moved vertically within the vertical hole 2d of the piston rod 2 by adjusting the bolt 43, thereby adjusting the opening and closing of the bypass channel 40 and the size of the flow path area when the valve is open. In addition to the needle valve 41, the damping force regulating valve can also be a lift valve or other valves capable of adjusting the damping force.

[0033] Subsequently, the auxiliary cylinder 4 is cylindrical and fits into the cover 10. Figure 1 The outer periphery of the annular protrusion 10b at the lower end is fixed to the cover 10 by welding and is housed in the compression side chamber R2 within the cylinder 1. Thus, the upper end of the auxiliary cylinder 4 is closed by the cover 10. In addition, the outer diameter of the auxiliary cylinder 4 is smaller than the inner diameter of the cylinder 1, forming an annular gap S between the auxiliary cylinder 4 and the cylinder 1.

[0034] Furthermore, a disc-shaped partition wall 4a1 is provided on the inner circumference of the auxiliary cylinder 4, dividing the auxiliary cylinder 4 into a hydraulic lock chamber L and a compensation chamber R on the opposite side of the piston of the hydraulic lock chamber L by the partition wall 4a1. In this embodiment, the auxiliary cylinder 4 is formed by two first cylinders 4a and second cylinders 4b that are axially overlapping and connected. Specifically, as Figure 1 As shown, the auxiliary cylinder 4 is formed by a bottomed cylindrical first cylinder 4a and a second cylinder 4b. The bottom of the bottomed cylindrical first cylinder 4a serves as a partition wall 4a1 to form a hydraulic lock chamber L. The second cylinder 4b is fitted into the outer periphery of the bottom side of the first cylinder 4a and forms a compensation chamber R by pressing the first cylinder 4a from the outer periphery.

[0035] The first cylinder 4a has a partition wall 4a1 formed by a disc-shaped bottom and a cylindrical portion 4a2 with an outer diameter smaller than that of the partition wall 4a1 and hanging down from the partition wall 4a1 toward the piston side. It is housed in the cylinder 1 and in the compression side chamber R2, and a hydraulic lock chamber L is formed inside it.

[0036] The locking plate 31 is axially movable and inserted into the first cylinder 4a. A spring 32, which is a conical helical spring, is installed between the locking plate 31 and the spacer wall 4a1. Additionally, in the cylinder portion 4a2... Figure 1 A stop ring 4a3 is installed on the inner circumference of the lower end to prevent the locking plate 31 from falling out of the hydraulic lock chamber L. The locking plate 31 is positioned against the stop ring 4a3 by the force exerted by the spring 32 while it is separated from the closed body 6 of the piston rod 2.

[0037] The locking plate 31 includes: a cylindrical portion 31a, which slides in contact with the inner circumference of the cylindrical portion 4a2 of the first cylinder 4a in the auxiliary cylinder 4; and an annular inclined portion 31b, which extends from the piston rod side end of the cylindrical portion 31a. Figure 1 The lower middle end is inclined at a certain angle towards the inner periphery and protrudes towards the piston rod side; and the annular sheet portion 31c extends inward from the inner periphery of the inclined portion 31b and sits on the closed body 6. Figure 1The upper middle part; and it can move axially within the first cylinder 4a.

[0038] Furthermore, a spring 32 is installed between the inner side of the inclined portion 31b of the locking plate 31 and the spacer wall 4a1 of the first cylinder 4a. The locking plate 31, separated from the closed body 6 of the piston rod 2, is positioned by the spring 32 to abut against the stop ring 4a3. The spring 32 is a conical helical spring; its lower end of the major diameter fits into an annular groove (not shown) provided along the circumferential direction on the inner circumference of the locking plate 31, and its upper end of the minor diameter abuts against the lower surface of the spacer wall 4a1, thus being installed between the locking plate 31 and the spacer wall 4a1 in a compressed state. Therefore, the spring 32 is radially positioned relative to the locking plate 31 and always applies force in the direction that causes the locking plate 31 to retract from the hydraulic lock chamber L. Additionally, since the spring 32 is a conical helical spring, its total length at maximum compression is shorter than that of a cylindrical helical spring, thus ensuring the stroke length of the locking plate 31 within the hydraulic lock chamber L and shortening the axial length of the hydraulic lock chamber L. This does not preclude the spring 32 from being a cylindrical helical spring. In addition, besides helical springs, the spring 32 can be any material that can apply force to the locking plate 31, and therefore can also be a wave washer, a butterfly spring, or an elastic body such as rubber.

[0039] The outer diameter of the cylindrical portion 31a of the locking plate 31 is slightly smaller than the inner diameter of the portion of the auxiliary cylinder 4 that forms the hydraulic lock chamber L, namely the cylindrical portion 4a2 of the first cylinder 4a. The liquid can pass through the gap between the outer periphery of the locking plate 31 and the inner periphery of the cylindrical portion 4a2 while being resisted.

[0040] Furthermore, the locking plate 31 and the closed body 6 mounted on the front end of the piston rod 2 are axially opposed, and the inner diameter of the opening 31c1, which is the inner circumference of the hole in the sheet portion 31c, becomes movable within the closed body 6. Figure 1 The diameter of the closed upper end face. Therefore, when the closed body 6 and the locking plate 31 are not in contact, the hydraulic locking chamber L and the compression side chamber R2 are connected through the gap between the inner periphery of the sheet portion 31c of the locking plate 31 and the outer periphery of the locking plate 31 and the inner periphery of the cylindrical portion 4a2 of the first cylinder 4a, but when the piston rod 2 moves relative to the cylinder 1... Figure 1 The sheet portion 31c moves from the upper middle part to the closed body 6. Figure 1 When the upper and middle end faces meet, the opening 31c1 on the inner circumferential side of the sheet portion 31c is closed by the sealing body 6, and the communication between the compression side chamber R2 on the inner circumferential side of the sheet portion 31c and the hydraulic lock chamber L is disconnected. The hydraulic lock chamber L and the compression side chamber R2 are connected only through the narrow gap between the outer circumference of the locking piece 31 and the inner circumference of the cylindrical portion 4a2 of the first cylinder 4a.

[0041] Furthermore, the locking piece 31 of this embodiment has an inclined portion 31b between the cylindrical portion 31a and the sheet portion 31c to reduce the internal stress generated by the load on the closure body 6 when it comes into contact with the sheet portion 31c. In the case of a structure where the sheet portion 31c is directly connected to the inner circumference of the cylindrical portion 31a without the inclined portion 31b, the shape change of the connection portion between the cylindrical portion 31a and the sheet portion 31c is greater than that when the inclined portion 31b is provided. Therefore, as described above, by providing the inclined portion 31b, the stress generated in the locking piece 31 is reduced, and fatigue of the locking piece 31 can be suppressed even after long-term use. In addition, even when the difference between the inner diameter of the sheet portion 31c and the outer diameter of the locking piece 31 increases due to the reduction of the inner diameter of the sheet portion 31c, fatigue can still be reduced by providing the inclined portion 31b, and the outer diameter of the closure body 6 can be miniaturized. Furthermore, as described above, as long as the closure 6 can abut against the sheet portion 31c and close the opening 31c1 on the inner periphery of the sheet portion 31c, the outer periphery shape of the head 6b or Figure 1 The shape of the upper and middle surfaces can be changed.

[0042] Subsequently, the second cylinder 4b is cylindrical and fits around the outer periphery of the annular protrusion 10b at the lower end of the cover 10 in Figure 2. It is fixed to the cover 10 by welding and is housed within the compression side chamber R2 inside the cylinder 1, forming a compensation chamber R inside. Furthermore, the inner diameter of the lower end of the second cylinder 4b in Figure 2 is larger than that of the upper end. It has a stepped portion 4b1 on its inner periphery and a radially penetrating throttling orifice 4b2 extending from the stepped portion 4b1 on the opposite side of the piston. The inner diameter of the lower end of the second cylinder 4b is set to the diameter into which the spacer wall 4a1 of the first cylinder 4a can be inserted. The axial length of the larger diameter portion 4b3 of the second cylinder 4b is longer than the axial length of the spacer wall 4a1 of the first cylinder 4a.

[0043] To connect the first cylinder 4a and the second cylinder 4b constructed in this manner, the side end of the partition wall of the first cylinder 4a is inserted into the inner side of the lower end of the second cylinder 4b, so that the partition wall 4a1 of the first cylinder 4a abuts against the stepped portion 4b1 of the second cylinder 4b. In this state, the second cylinder 4b and the first cylinder 4a are connected by plastically deforming the partition wall 4a1 by pressing the larger inner diameter portion 4b3 of the lower end of the second cylinder 4b from the outer periphery as a pressing part. Thus, when the auxiliary cylinder 4 is formed using a bottomed cylindrical first cylinder 4a that forms the hydraulic lock chamber L, and a second cylinder 4b that fits into the outer periphery of the spacer wall side of the first cylinder 4a and forms the compensation chamber R by pressing the first cylinder 4a from the outer periphery, the auxiliary cylinder 4 can be manufactured economically and easily because there is no deformation caused by welding in the first cylinder 4a and the second cylinder 4b, and no post-processing of the inner peripheral surfaces of the first cylinder 4a and the second cylinder 4b is required. Furthermore, since the hydraulic lock chamber L is formed using the bottomed cylindrical first cylinder 4a, there is no need to worry about liquid leaking from the hydraulic lock chamber L into the compression side chamber R2 through the space between the cylinder portion 4a2 and the locking plate 31 when the hydraulic lock function is being performed, thus ensuring stable operation of the hydraulic lock function. In addition, by forming the auxiliary cylinder 4 from the first cylinder 4a and the second cylinder 4b with the spacer wall 4a1 in this way, the hydraulic lock chamber L and the compensation chamber R can be liquid-tightly separated even without a sealing component.

[0044] Furthermore, a free piston 30 is inserted into the second cylinder 4b, which forms the compensation chamber R within the inner circumference of the auxiliary cylinder 4. This free piston 30 is axially movable and slides in contact with the inner circumference of the second cylinder 4b, dividing the compensation chamber R into a gas chamber G and a liquid chamber A. The free piston 30 has a sealing ring 30a on its outer circumference that slides in contact with the auxiliary cylinder 4, sealing the gas chamber G and the liquid chamber A. The gas chamber G is filled with compressed gas, and the liquid chamber A is filled with the same liquid as that filled in the elongated side chamber R1 and the compressed side chamber R2. In addition, in the buffer D of this embodiment, the free piston 30 is used to divide the compensation chamber R into a gas chamber G and a liquid chamber A, but elastic partition walls that can change the volume distribution of the gas chamber G and the liquid chamber A, such as airbags, diaphragms, or bellows, can also be used.

[0045] The throttling orifice 4b2 located in the second cylinder 4b is positioned closer to the range of movement of the free piston 30. Figure 1The lower middle section connects the compression chamber R2 and the compensation chamber R to the liquid chamber A, which exerts resistance on the liquid flow traveling between the compression chamber R2 and the liquid chamber A. Furthermore, in this embodiment, the cross-sectional area of ​​the annular gap S between the auxiliary cylinder 4 and the cylinder 1 is larger than the opening area of ​​the throttle orifice 4b2. The resistance exerted by the annular gap S on the liquid flow through this annular gap S is not greater than the resistance exerted by the throttle orifice 4b2 on the liquid flow through this throttle orifice 4b2. In this embodiment, the throttle orifice 4b2 exerts resistance on the liquid flow traveling between the compression chamber R2 and the compensation chamber R to the liquid chamber A. However, the flow path area of ​​the aforementioned annular gap S can also be reduced to exert resistance on the liquid flow traveling between the compression chamber R2 and the compensation chamber R to the liquid chamber A, thus using the annular gap S as a flow restriction path. In this case, instead of the throttle orifice 4b2, a hole is provided on the second cylinder 4b in the auxiliary cylinder 4 that exerts almost no resistance to the flow of liquid, so that the liquid chamber A can be connected to the compression side chamber R2 via the annular gap S.

[0046] Furthermore, even if the liquid in the compensation chamber R leaks from the lower end portion 4b3 of the first cylinder 4a and the second cylinder 4b, which forms the crimping part, into the compression side chamber R2, since the joint portion of the first cylinder 4a and the second cylinder 4b only faces the liquid chamber A, and the liquid chamber A and the compression side chamber R2 are always in a connected state, no problem will occur. Since the hydraulic lock chamber L is formed inside the bottomed cylindrical first cylinder 4a, it will not have any effect on the hydraulic lock chamber L.

[0047] In addition, as long as the second cylinder 4b can maintain the first cylinder 4a by fitting the second cylinder 4b into the outer periphery of the first cylinder 4a, the second cylinder 4b can also hold the first cylinder 4a by fitting.

[0048] The buffer D is constructed as described above. The operation of the buffer D is explained below. First, the operation of the buffer D during its extension is explained. When the piston rod 2 moves relative to the cylinder 1... Figure 1When the buffer D extends while the piston 3 moves downwards, the liquid in the extended side chamber R1, which is reduced by the piston 3, moves through the extended side channel 3b to the expanded compression side chamber R2, which is pushed open by the extended side vane valve 7. Because the extended side vane valve 7 resists the flow of this liquid, the pressure in the extended side chamber R1 rises, creating a pressure difference between the extended side chamber R1 and the compression side chamber R2. This generates a damping force on the extended side of the buffer D that hinders the extension action. During the extension action of the buffer D, the piston rod 2 retracts from the cylinder 1. Therefore, the volume of liquid retracted from the cylinder 1 by the piston rod 2 is insufficient in the compression side chamber R2. However, the insufficient liquid is displaced towards the free piston 30 in the direction of expanding the gas chamber G in the auxiliary cylinder 4, and supplied from the liquid chamber A to the compression side chamber R2. Additionally, when the needle valve 41 opens, liquid can also move from the extended side chamber R1 to the compression side chamber R2 through the bypass channel 40. Therefore, if needle valve 41 is opened to its maximum extent, maximizing the flow area of ​​bypass channel 40, the damping force during the extension of buffer D is minimized. Conversely, if needle valve 41 is closed, cutting off bypass channel 40, damping force is generated only by the extension-side vane valve 7, resulting in the maximum damping force during the extension of buffer D. Thus, by adjusting the opening of needle valve 41, which acts as a damping force regulating valve, the damping force during the extension of buffer D can be adjusted between minimum and maximum.

[0049] Conversely, this describes the action of the buffer D during its retraction. When the piston rod 2 moves relative to the cylinder 1... Figure 1 When the upper and middle parts move and the buffer D contracts, the liquid in the compression-side chamber R2, which is reduced by the piston 3, moves through the compression-side channel 3c to the extension-side chamber R1, which is expanded by pushing open the compression-side vane valve 8. Because the compression-side vane valve 8 resists the flow of this liquid, the pressure in the compression-side chamber R2 rises, creating a pressure difference between the compression-side chamber R2 and the extension-side chamber R1. This generates a damping force on the compression side of the buffer D that hinders the contraction action. During the contraction action of the buffer D, because the piston rod 2 penetrates into the cylinder 1, the volume of liquid penetrating the cylinder 1 by the piston rod 2 becomes excess in the compression-side chamber R2. However, the excess liquid flows through the throttle orifice 4b2 into the liquid chamber A of the compensation chamber R, and the free piston 30 displaces in the auxiliary cylinder 4 in the direction that causes the gas chamber G to contract. In addition, the compensation chamber R connects the compression side chamber R2 and the liquid chamber A through the throttling orifice 4b2. The pressure in the compression side chamber R2 can exceed the pressure in the liquid chamber A and rise. Therefore, compared with the conventional single-rod type buffer, the buffer D can generate a larger damping force on the compression side.

[0050] Furthermore, when needle valve 41 is open, liquid can also move from the compression side chamber R2 to the extension side chamber R1 through bypass passage 40. Therefore, if needle valve 41 is opened to its maximum extent, maximizing the flow area of ​​bypass passage 40, the damping force during the contraction action of buffer D is minimized. If needle valve 41 is closed, cutting off bypass passage 40, the damping force during the contraction action of buffer D is maximized only by the compression side vane valve 8 and the throttle orifice 4b2. Thus, by adjusting the opening degree of needle valve 41, which acts as a damping force regulating valve, the damping force during the contraction action of buffer D can be adjusted between minimum and maximum.

[0051] During the retraction action of the buffer D, the piston rod 2 moves relative to the cylinder 1. Figure 1 When the piston rod moves upward, the closure 6 mounted on the front end of the piston rod 2 soon comes into contact with the sheet portion 31c of the locking plate 31 inside the hydraulic lock chamber L. Thus, when the closure 6 comes into contact with the locking plate 31, the opening 31c1 of the sheet portion 31c of the locking plate 31 is closed by the closure 6, and the communication between the hydraulic lock chamber L and the compression side chamber R2 through the opening 31c1 on the inner circumference of the sheet portion 31c is disconnected. If the piston rod 2 is further moved relative to the cylinder 1 from this state... Figure 1 As the buffer D contracts due to the upward movement of the locking plate 31, the locking plate 31 is pushed by the sealing body 6 and moves towards the compression hydraulic lock chamber L, with the sealing body 6 inserted into the hydraulic lock chamber L. With the sealing body 6 in contact with the sheet portion 31c of the locking plate 31, the hydraulic lock chamber L and the compression side chamber R2 are connected only through the gap between the locking plate 31 and the auxiliary cylinder 4. Therefore, by moving the piston rod 2 relative to the cylinder 1 in the contraction direction, the piston rod 2 penetrates into the hydraulic lock chamber L. When the locking plate 31, pushed by the sealing body 6, shrinks the hydraulic lock chamber L, the liquid in the hydraulic lock chamber L moves towards the compression side chamber R2 while encountering resistance in the gap. Therefore, the pressure in the hydraulic lock chamber L rises above the compression side chamber R2, and the piston rod 2 and the locking plate 31 are pushed towards the compression side chamber R2 by the pressure within the hydraulic lock chamber L. Figure 1 Push down from the middle to the lower part.

[0052] Thus, when the buffer D is displaced to near the end of its stroke on the contraction side, the sealing body 6 abuts against the locking plate 31, causing the pressure in the hydraulic lock chamber L to rise and activating the hydraulic lock function. Therefore, the buffer D generates a greater damping force on the compression side by adding the resistance generated by the pressure rise in the hydraulic lock chamber L to the damping force generated by the compression side vane valve 8. In addition, since the sealing body 6 closes the vertical hole 2d of the piston rod 2, the pressure in the hydraulic lock chamber L will not escape to the extension side chamber R1 through the bypass channel 40. Therefore, the damping force can be adjusted, and the hydraulic lock function can be activated when the buffer D is near the end of its stroke, thereby suppressing further contraction of the buffer D.

[0053] When the buffer D extends from near the end of its stroke during the contraction action, the piston rod 2 exits from the hydraulic lock chamber L, and the locking plate 31 returns to its initial position abutting against the stop ring 4a3 before being compressed by the spring 32 into the hydraulic lock chamber L.

[0054] The buffer D of this embodiment includes: a cylinder 1; a piston rod 2, which is axially movable and inserted into the cylinder 1; a piston 3, which is connected to the piston rod 2 and axially movable and inserted into the cylinder 1, dividing the cylinder 1 into an extension side chamber R1 and a compression side chamber R2; an extension side vane valve (extension side damping valve) 7, which applies resistance to the fluid flow from the extension side chamber R1 to the compression side chamber R2; a compression side vane valve (compression side damping valve) 8, which applies resistance to the fluid flow from the compression side chamber R2 to the extension side chamber R1; a bypass passage 40, which is provided on the piston rod 2 and bypasses the extension side vane valve (extension side damping valve) 7 and the compression side vane valve (compression side damping valve) 8 to connect the extension side chamber R1 and the compression side chamber R2; a needle valve (damping force regulating valve) 41, which is provided in the bypass passage 40; and a secondary cylinder 4, which contains... The cylinder 1 is housed in the compression chamber R2; a partition wall 4a1 divides the auxiliary cylinder 4 into a hydraulic lock chamber L and a compensation chamber R opposite to the piston of the hydraulic lock chamber L; a locking plate 31 has an opening (hole) 31c1 and can be axially inserted into the auxiliary cylinder 4 and the hydraulic lock chamber L; and a sealing body 6 is provided at the front end of the piston rod 2 and closes the opening (hole) 31c1 when it abuts against the locking plate 31; the compensation chamber R has a gas chamber G and a liquid chamber A communicating with the compression chamber R2; the bypass channel 40 is formed by including a vertical hole 2d opening from the front end of the piston rod 2, a first transverse hole 2e opening from the side of the piston rod 2 to communicate the compression chamber R2 with the vertical hole 2d, and a second transverse hole 2f opening from the side of the piston rod 2 to communicate the elongation chamber R1 with the vertical hole 2d; and the sealing body 6 closes the opening of the vertical hole 2d of the piston rod 2.

[0055] In the buffer D of this embodiment, when it is in a contraction action, the piston rod 2 moves in the contraction direction and the closing body 6 abuts against the locking plate 31. The opening (hole) 31c1 of the locking plate 31 is closed by the closing body 6, and the locking plate 31 is pushed into the hydraulic locking chamber L. Therefore, the pressure in the hydraulic locking chamber L increases, and the resistance that inhibits the movement of the piston rod 2 is added to the damping force during the contraction action. In addition, since the closing body 6 closes the vertical hole 2d of the piston rod 2, the pressure in the hydraulic locking chamber L will not escape to the extension side chamber R1 through the bypass channel 40. Therefore, the damping force can be adjusted, and the hydraulic locking function is activated when the buffer D is near the end of its stroke, thus inhibiting further contraction of the buffer D. Therefore, according to the buffer D of this embodiment, the damping force can be adjusted, and a greater damping force than conventional buffers can be generated when the buffer D is near the end of its stroke. Furthermore, if the buffer D constructed in this manner is used between the body and wheels of a straddle-type vehicle, it can suppress the so-called bottoming out when the straddle-type vehicle retracts to the end of its travel while driving on rough roads.

[0056] Furthermore, the buffer D of this embodiment can generate a large damping force when it contracts to near the end of its stroke. Therefore, even if the impact buffer rubber 18 does not generate a large elastic force, it can still mitigate the impact at the point of maximum contraction, and can also achieve miniaturization and weight reduction of the impact buffer rubber 18. In addition, the buffer D of this embodiment can generate a large damping force when it contracts to near the end of its stroke. Therefore, as the suspension spring 26 is continuously compressed, it is not necessary to change the spring constant to compensate for insufficient damping force. Thus, the structure of the suspension spring 26 becomes simpler, and productivity is improved.

[0057] Furthermore, the buffer D in this embodiment includes: a locking plate 31 having an opening (hole) 31b and being axially movable and inserted into the auxiliary cylinder 4 and the hydraulic locking chamber L; a spring 32, which is installed between the locking plate 31 and the partition wall 4a1 and applies force to the locking plate 31 toward the piston side; and a closing body 6, which is provided at the front end of the piston rod 2 and closes the opening (hole) 31c1 when it abuts against the locking plate 31.

[0058] According to the buffer D constructed in this way, the piston rod 2 is close to the auxiliary cylinder 4, and the opening (hole) 31c1 of the locking plate 31 of the hydraulic lock chamber L is closed by the sealing body 6 located on the side of the piston rod 2. The hydraulic lock chamber L can be compressed by the piston rod 2, the sealing body 6 and the locking plate 31. Therefore, even if there is an offset between the axis of the piston rod 2 and the auxiliary cylinder 4, the hydraulic lock chamber L can be compressed to increase the pressure in the hydraulic lock chamber L, and the desired larger damping force on the compression side can be obtained near the end of the stroke.

[0059] Furthermore, in the buffer D of this embodiment, when the hydraulic lock chamber L is compressed, the liquid flowing from the hydraulic lock chamber L toward the compression side chamber R2 passes through the gap between the locking plate 31 and the auxiliary cylinder 4. This gap exerts resistance on the flow of the liquid, causing the pressure inside the hydraulic lock chamber L to rise. Alternatively, the locking plate 31 and the inner circumference of the auxiliary cylinder 4 can slide into contact, replacing this gap. Instead, a passage is formed between the locking plate 31 or the sealing body 6, or between the locking plate 31 and the sealing body 6, or on the piston rod 2, functioning as a throttling orifice or a choke. By allowing the liquid to pass through this passage, the pressure inside the hydraulic lock chamber L rises. Furthermore, a throttling orifice or a choke connecting the hydraulic lock chamber L and the compression side chamber R2 can also be provided in the auxiliary cylinder 4. Furthermore, the head 6b of the sealing body 6 is disc-shaped, but as described above, when it abuts against the locking plate 31, it closes the opening (hole) 31c1 of the locking plate 31. When the piston rod 2 enters the hydraulic lock chamber L, as long as the hydraulic lock chamber L and the locking plate 31 can be compressed together, the shape and structure can be appropriately modified. In addition, even if a groove is provided in one or both of the abutting surfaces of the sealing body 6 or the locking plate 31, and the groove acts as a throttling orifice or choke ring for increasing the pressure in the hydraulic lock chamber L, the opening (hole) 31c1 will not be completely closed when the sealing body 6 abuts against the locking plate 31. However, this situation is also included in the concept of the sealing body 6 closing the opening (hole) 31c1 as long as the function of the hydraulic lock chamber L can be achieved.

[0060] In addition, the locking plate 31 can be made of metal, but if it is made of resin, it can reduce the impact noise when it comes into contact with the enclosure 6, and can prevent damage to the inner circumferential surface of the auxiliary cylinder 4 when it moves inside the auxiliary cylinder 4.

[0061] Furthermore, in the damper D of this embodiment, the auxiliary cylinder 4 has a throttle orifice 4b2 on its side that connects the compression chamber R2 to the liquid chamber A. Therefore, during the contraction action of the damper D, the pressure in the compression chamber R2 can be made higher than the pressure in the compensation chamber R, thereby increasing the damping force on the compression side during the contraction action. Therefore, if the damper D constructed in this manner is used between the body and wheels of a suspension straddle-type vehicle, bottoming out can be further suppressed when the suspension straddle-type vehicle is traveling on rough roads.

[0062] Furthermore, in the buffer D of this embodiment, the piston 3 is annular and installed on the outer periphery of the piston rod 2, and has an elongation side channel 3b and a compression side channel 3c that connect the elongation side chamber R1 and the compression side chamber R2. The elongation side damping valve is an annular, with its inner periphery fixed to the outer periphery of the piston rod 2 and overlapping with the compression side chamber side end of the piston 3 to open and close the elongation side channel 3b. The compression side damping valve is an annular, with its inner periphery fixed to the outer periphery of the piston rod 2 and overlapping with the elongation side chamber side end of the piston 3 to open and close the compression side channel 3c. It has a piston nut 27 that is threadedly engaged with the outer periphery of the piston rod 2 to fix the piston 3, the elongation side vane valve 7 and the compression side vane valve 8 to the outer periphery of the piston rod 2. The sealing body 6 is separated from the piston nut 27.

[0063] In the buffer D constructed in this manner, when the buffer D retracts near the end of its stroke, the closed body 6 provided on the piston rod 2 abuts against the locking plate 31 and compresses the hydraulic lock chamber L together with the locking plate 31, causing the pressure inside the hydraulic lock chamber L to rise. The pressure inside the hydraulic lock chamber L pushes the closed body 6 relative to the piston rod 2 towards the piston 3 side. However, since the closed body 6 is separated from the piston nut 27, the axial load borne by the closed body 6 due to the pressure of the hydraulic lock chamber L is directly received by the piston rod 2 and does not act on the compression-side vane valve 8, piston 3, and extension-side vane valve 7 via the piston nut 27. Therefore, according to the buffer D of this embodiment constructed in this manner, even if the closed body 6 is provided on the piston rod 2, since the axial load borne by the closed body 6 due to the pressure of the hydraulic lock chamber L does not act on the compression-side vane valve 8, piston 3, and extension-side vane valve 7, it is possible to prevent the deterioration of the compression-side vane valve 8, piston 3, and extension-side vane valve 7, and to generate damping forces on both the extension and compression sides as designed.

[0064] Furthermore, in the buffer D of this embodiment, the closing body 6 is pressed into the vertical hole 2d and positioned radially opposite the piston nut 27. According to the buffer D constructed in this manner, by pressing in the closing body 6, the threaded portion 2b of the piston rod 2, to which the piston nut 27 is threaded, is enlarged. The piston nut 27 will not rotate relative to the threaded portion 2b and become loose, and no anti-rotation parts or machining are required for the piston nut 27, thus reducing the manufacturing cost of the buffer D.

[0065] In this embodiment, the sealing body 6 includes an insertion shaft 6a that is pressed into the vertical hole 2d of the piston rod 2, and a head 6b located at the front end of the insertion shaft 6a and abutting against the front end of the piston rod 2. Therefore, even if a large load is applied to the sealing body 6 due to the pressure of the hydraulic lock chamber L, the movement of the sealing body 6 toward the piston rod 2 is further restricted when the head 6b abuts against the piston rod 2. Therefore, if the piston nut 27 is threaded into a position spaced away from the front end of the piston rod 2 toward the opposite side of the auxiliary cylinder, the load from the sealing body 6 can be reliably prevented from being transmitted to the piston nut 27.

[0066] The closure body 6 only needs to be able to close the opening (hole) 31c1 of the sheet portion 31c when it abuts against the locking plate 31. Therefore, it may not need to have a head 6b. However, in this case, as long as a step is provided in the vertical hole 2d of the piston rod 2 that can abut against the opposite end of the auxiliary cylinder of the closure body 6, the step can be used to restrict the intrusion of the closure body 6 into the piston rod 2. When subjected to the load caused by the pressure of the hydraulic locking chamber L, the entire closure body 6 will not be pushed into the piston rod 2.

[0067] Furthermore, in the buffer of this embodiment, the locking plate 31 includes: a cylindrical portion 31a that slides in contact with the inner circumference of the auxiliary cylinder 4; an annular inclined portion 31b that inclines from the piston rod side end of the cylindrical portion 31a toward the inner circumference and protrudes toward the piston rod side; and an annular sheet portion 31c that extends inward from the inner circumference of the inclined portion 31b and sits on the enclosure 6. With the buffer D constructed in this manner, the stress generated inside the locking plate 31 due to the load experienced when the enclosure 6 abuts against the sheet portion 31c is reduced, and fatigue of the locking plate 31 can be suppressed even after prolonged use. Furthermore, as described above, the inclined portion 31b is inclined at a certain angle relative to the cylindrical portion 31a, but it can also be inclined by changing the angle relative to the cylindrical portion 31a in stages, or it can be bent to be inclined.

[0068] Furthermore, the auxiliary cylinder 4 in the buffer D of this embodiment includes: a bottomed cylindrical first cylinder 4a, which is a bottomed cylindrical shape and forms a hydraulic lock chamber L by using its bottom as a partition wall 4a1; and a second cylinder 4b, which fits into the outer periphery of the bottom side end of the first cylinder 4a and holds the first cylinder 4a to form a compensation chamber R. According to the buffer D constructed in this way, since it is not necessary to weld the first cylinder 4a and the second cylinder 4b, there will be no deformation caused by welding, and it is not necessary to perform post-processing on the inner peripheral surfaces of the first cylinder 4a and the second cylinder 4b. Therefore, the auxiliary cylinder 4 can be manufactured economically and easily. Furthermore, since the hydraulic lock chamber L is formed by using the bottomed cylindrical first cylinder 4a, when the hydraulic lock function is performed, there is no need to worry about liquid leaking from the hydraulic lock chamber L into the compression side chamber R2 through the space between the first cylinder 4a and the locking plate 31, and the hydraulic lock function can be performed stably.

[0069] Furthermore, the vertical arrangement of the gas chamber G and the liquid chamber A in the compensation chamber R can also be... Figure 1 The opposite is true. Furthermore, in the buffer D of this embodiment, a throttling orifice 4b2 is provided in the auxiliary cylinder 4 to connect the liquid chamber A and the compression chamber R2, assisting in the pressure rise in the compression chamber R2 during the contraction action. However, it is also possible to use an orifice that cannot function as a throttling orifice to connect the liquid chamber A and the compression chamber R2, and to provide a flow-limiting path that applies resistance to the flow of liquid in the gap between the cylinder 1 and the auxiliary cylinder 4, thereby assisting in the pressure rise in the compression chamber R2 during the contraction action. However, when assisting in the pressure rise in the compression chamber R2 during the contraction action through the throttling orifice 4b2, which allows for easy area management, the advantage of easily adjusting the pressure in the compression chamber R2 and the pressure in the liquid chamber A can be enjoyed.

[0070] Furthermore, in the buffer D of this embodiment, since the auxiliary cylinder 4 is held by the cover 10, the components assembled on the auxiliary cylinder 4 can be assembled together with the auxiliary cylinder 4 on the cover 10 to form an auxiliary cylinder assembly, thus facilitating the assembly of the buffer D. However, the structure in which the auxiliary cylinder 4 is housed and fixed within the cylinder 1 is not limited to... Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 Figure 1 As shown, appropriate design changes can be made.

[0071] Alternatively, the first cylinder forming the hydraulic lock chamber L can be cylindrical, and the second cylinder, which is connected to the cover 10 to form the compensation chamber R, can be cylindrical with a bottom. The first cylinder is connected to the second cylinder by fitting the first cylinder into the outer periphery of the bottom side of the second cylinder, so that the first cylinder faces the bottom of the second cylinder and is pressed from the outer periphery to form the auxiliary cylinder 4.

[0072] Furthermore, the auxiliary cylinder 4 is formed by pressing and connecting a bottomed cylindrical first cylinder 4a and a cylindrical second cylinder 4b. For example, the two cylinders and the spacer wall between them can also be connected by welding to form the auxiliary cylinder 4. That is, the structure of the auxiliary cylinder 4 can be appropriately designed and modified.

[0073] The preferred embodiments of the present invention have been described in detail above, but modifications, variations and alterations are possible as long as they do not depart from the scope of the patent application. Symbol Explanation

[0074] 1 cylinder 2 Piston rod 2D vertical hole 2e First transverse hole 2f Second transverse hole 3 Pistons 3b Elongated side channel 3c compression side channel 4 auxiliary cylinders 4a First tube 4a1 partition wall 4b Second tube 6. Closed body 6a Insert shaft 6b Head 7. Extended-side vane valve (extended-side damping valve) 8. Compression-side vane valve (compression-side damping valve) 27 Piston Nut 31 locking plate 31a Cylinder section 31b Inclined section 31c Sheet Department 31c1 Opening (hole) 32 Springs 40 Bypass lane 41. Needle valve (damping force regulating valve) A liquid chamber D buffer G gas chamber L Hydraulic lock chamber R Compensation Chamber R1 elongated side chamber R2 compression side chamber

Claims

1. A damper comprising: a cylinder; a piston rod axially movably inserted into the cylinder; a piston coupled to the piston rod to be axially movably inserted into the cylinder and dividing the cylinder into an extension side chamber and a compression side chamber; an extension side damping valve applying resistance to liquid flow from the extension side chamber toward the compression side chamber; a compression side damping valve applying resistance to liquid flow from the compression side chamber toward the extension side chamber; a bypass passage provided in the piston rod and communicating the extension side chamber and the compression side chamber while bypassing the extension side damping valve and the compression side damping valve; a damping force adjusting valve provided in the bypass passage; a sub-cylinder accommodated in the compression side chamber in the cylinder; a partition wall dividing the sub-cylinder into a hydraulic lock chamber and a compensation chamber on the opposite side of the hydraulic lock chamber from the piston; a lock piece having a hole and being axially movably inserted into the sub-cylinder and the hydraulic lock chamber; and a closure provided at the front end of the piston rod and closing the hole when abutting against the lock piece; the compensation chamber having a gas chamber and a liquid chamber communicating with the compression side chamber, the bypass passage being formed of a vertical hole opened at the front end of the piston rod, a first horizontal hole opened at the side of the piston rod to communicate the compression side chamber with the vertical hole, and a second horizontal hole opened at the side of the piston rod to communicate the extension side chamber with the vertical hole, and the closure closing the opening of the vertical hole of the piston rod.

2. The damper according to claim 1, wherein the piston is annular and fitted to the outer periphery of the piston rod, and has an extension side passage and a compression side passage communicating the extension side chamber and the compression side chamber, the extension side damping valve is annular and has an inner periphery fixed to the outer periphery of the piston rod, and is a vane valve overlapping the compression side chamber side end of the piston to open and close the extension side passage, the compression side damping valve is annular and has an inner periphery fixed to the outer periphery of the piston rod, and is a vane valve overlapping the extension side chamber side end of the piston to open and close the compression side passage, the damper comprises a piston nut threadedly coupled to the outer periphery of the piston rod to fix the piston, the extension side vane valve, and the compression side vane valve to the outer periphery of the piston rod, and the closure is spaced apart from the piston nut.

3. The damper according to claim 2, wherein the closure is pressed into the vertical hole and positioned in diametrically opposite relation to the piston nut.

4. The damper according to claim 1, wherein the lock piece has a cylindrical portion in sliding contact with the inner periphery of the sub-cylinder, an annular inclined portion inclined toward the inner periphery side from the piston rod side end of the cylindrical portion and protruding toward the piston rod side, and an annular sheet portion extending toward the inner side from the inner periphery of the inclined portion to be seated on and off the closure.

5. The damper according to claim 1, wherein the closure comprises an insertion shaft inserted into the vertical hole, and a head portion provided at the front end of the insertion shaft to abut against the front end of the piston rod.

6. The damper according to claim 1, wherein ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ The sub-cylinder has a first cylinder which is a bottomed cylinder, forms the hydraulic lock chamber with the bottom as the partition wall, and a second cylinder which is fitted to the outer periphery of the bottom side end of the first cylinder and holds the first cylinder to form the compensation chamber.

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