Shock absorber

Abstract

A shock absorber (D) is provided with: a cylinder (1); a piston rod (2); a piston (3) connected to the piston rod (2) and dividing the inside of the cylinder (1) into an extension-side chamber (R1) and a compression-side chamber (R2); an outer cylinder (4) forming a reservoir chamber (R) between the outer cylinder (4) and the cylinder (1); an extension-side main valve (7); a compression-side main valve (11) and a compression-side sub-valve (13) provided in series between the compression-side chamber (R2) and the reservoir (R); and an extension-side sub-valve (12) and a suction check valve (14) provided in series between the reservoir (R) and the compression-side chamber (R2). When the piston speed during the extension operation is in a slightly low speed range, the damping force is generated only by the extension-side sub-valve (12), and when the piston speed during the contraction operation is in a slightly low speed range, the damping force is generated only by the compression-side sub-valve (13).

Description

Technical Field This invention relates to a buffer. Background Technology For example, to improve vehicle ride comfort, dampers are installed and used between the vehicle body and wheels to suppress vibrations of the body and wheels through damping forces generated during extension and retraction. Such a damper includes, for example, a cylinder, a rod that can be freely inserted into the cylinder, a piston that can be freely inserted into the cylinder and divides the cylinder into an extension side chamber and a compression side chamber, a free piston that can be freely inserted into the cylinder and divides the cylinder below the compression side chamber, a damping channel disposed on the piston and connecting the extension side chamber and the compression side chamber, and a damping valve disposed on the damping channel. In recent years, for vehicle shock absorbers, in order to improve vehicle ride comfort, it is desirable to achieve the following damping force characteristics: increasing the damping coefficient in the micro-low speed range where the extension speed is lower than the low speed, so that the damping force increases rapidly relative to the extension stroke; making the damping coefficient smaller than the micro-low speed range in the low speed range; and making the damping coefficient proportional to the extension speed in the medium and high speed range above the low speed range, but smaller than in the low speed range. To meet this requirement, as disclosed in JP2019-183918A, the damping valve includes: a vane valve that is annular and whose inner circumferential side is fixed while allowing bending of the outer circumferential side; and a valve seat component that is annular and has an annular opposing seat portion that is non-contacting with the outer circumference of the vane valve and a port on the inner circumferential side of the opposing seat portion; thereby applying resistance to the flow of hydraulic oil reciprocating between the extension side chamber and the compression side chamber. In a damping valve constructed in this way, when the extension and retraction speed of the buffer is in the low-speed range, the flow path area between the vane valve and the opposing seat is limited to a very small size because the vane valve does not bend significantly. Therefore, a damping force characteristic that increases sharply in response to the extension and retraction speed can be obtained, and a damping force characteristic suitable for vehicles can be achieved.

[0007] Existing technical documents Patent documents Patent Document 1: JP2019-183918A Summary of the Invention The problem that the invention aims to solve Traditional damping valves, with their vane valves and opposing seats, provide good damping force characteristics for the damper when it extends or retracts at low speeds. However, if used in multi-cylinder dampers with smaller cylinder diameters, the inner diameter of the opposing seat will naturally be reduced. But due to strength issues, the outer diameter of the part where the vane valve is installed on the piston rod cannot be reduced, nor can the outer diameter of the gasket supporting the inner circumference of the vane valve. This results in a smaller difference between the inner and outer diameters of the vane valve. If the difference between the inner and outer diameters of the vane valve becomes smaller, and the vane valve bends and is axially separated from the opposing seat, in order to ensure a larger flow path area, the bending amount of the vane valve needs to be increased. However, this will cause the vane valve to be subjected to greater stress, leading to vane valve fatigue. Therefore, it is difficult to use the conventional damping valve in multi-cylinder buffers to improve the damping force characteristics in the low-speed range. The purpose of this invention is to provide a damper that, even in a multi-cylinder type, provides good damping characteristics in the low-speed range of the piston and improves the ride comfort of the vehicle.

[0010] Problem-solving methods To achieve the aforementioned objective, the buffer of the present invention is characterized by comprising: a cylinder; a piston rod axially movable and insertable into the cylinder; a piston connected to the piston rod and axially movable and insertable into the cylinder to divide the cylinder into an elongated side chamber and a compression side chamber filled with liquid; an outer cylinder covering the outer periphery of the cylinder and forming a liquid reservoir between the outer cylinder and the outer cylinder; an elongated side main valve that applies resistance to the liquid flow from the elongated side chamber toward the compression side chamber; and a compression side main valve and a compression side auxiliary valve, connected in series between the compression side chamber and the liquid reservoir, for controlling the flow of liquid from the elongated side chamber toward the compression side chamber. The compression chamber applies resistance to the liquid flow toward the reservoir chamber; the extension side auxiliary valve, located between the reservoir chamber and the compression chamber, applies resistance to the liquid flow from the reservoir chamber toward the compression chamber; and the suction check valve, connected in series with the extension side auxiliary valve between the reservoir chamber and the compression chamber, allows liquid flow only from the reservoir chamber toward the compression chamber; when the piston speed is in a very low range during the extension action, only the extension side auxiliary valve generates the damping force, and when the piston speed is in a very low range during the contraction action, only the compression side auxiliary valve generates the damping force. In a buffer constructed in this way, when the piston speed is in a very low speed range, the damping force can be generated by the extension side auxiliary valve or the compression side auxiliary valve located between the compression side chamber and the reservoir chamber. It is not necessary to place the extension side auxiliary valve and the compression side auxiliary valve on the piston rod, which can increase the flow path area of ​​the extension side auxiliary valve and the compression side auxiliary valve when they are open. Attached Figure Description Figure 1 This is a longitudinal sectional view of a buffer according to one embodiment of the present invention.

[0013] Figure 2 This is a partially enlarged longitudinal sectional view of the buffer in one embodiment of the present invention.

[0014] Figure 3 This is a top view of the first spacer wall of the buffer in one embodiment of the present invention.

[0015] Figure 4 This is a graph showing the damping force characteristics of a buffer in one embodiment of the present invention.

[0016] Figure 5 This is a partially enlarged longitudinal sectional view of the buffer in a modified embodiment of the present invention.

[0017] Implementation The present invention will now be described based on the illustrated embodiments. Figure 1 and Figure 2 As shown, in one embodiment, the buffer D includes: a cylinder 1; a piston rod 2 axially movable and inserted into the cylinder 1; a piston 3 connected to the piston rod 2 and axially movable and inserted into the cylinder 1 to divide the cylinder 1 into a liquid-filled elongation side chamber R1 and a liquid-filled compression side chamber R2; an outer cylinder 4 covering the outer periphery of the cylinder 1 and forming a liquid reservoir R between the outer cylinder 4 and the cylinder 1; an elongation side main valve 7 that applies resistance to the liquid flow from the elongation side chamber R1 toward the liquid-filled compression side chamber R2; and a liquid-filled compression side main valve. A compression-side auxiliary valve 11 and a compression-side auxiliary valve 13 are connected in series between the compression-side chamber R2 and the reservoir R, applying resistance to the liquid flow from the compression-side chamber R2 to the reservoir R; an extension-side auxiliary valve 12 is located between the reservoir R and the compression-side chamber R2, applying resistance to the liquid flow from the reservoir R to the compression-side chamber R2; and a suction check valve 14 is connected in series with the extension-side auxiliary valve 12 between the reservoir R and the compression-side chamber R2, allowing only the liquid flow from the reservoir R to the compression-side chamber R2. A damper D is installed between the vehicle body and the axle in a vehicle (not shown) and generates a damping force during extension and retraction to suppress vehicle body vibration. The following will describe in detail the various parts of the buffer D. The cylinder 1 is cylindrical, and as described above, its interior is freely inserted by the piston 3. Furthermore, the cylinder 1 is divided by the piston 3 into sections... Figure 1 The elongated side chamber R1, located higher up in the middle piston 3, and compared to... Figure 1 The compression chamber R2 is located further below the piston 3. Additionally, the elongation chamber R1 and the compression chamber R2 within the cylinder 1 are filled with a liquid, such as hydraulic oil. Furthermore, besides hydraulic oil, water, aqueous solutions, etc., may also be filled with the liquid. A bottomed cylindrical outer cylinder 4 is provided on the outer periphery of the cylinder 1, covering the outer periphery of the cylinder 1. An annular gap is provided between the outer cylinder 4 and the cylinder 1, forming a reservoir R. Thus, the buffer D is configured as a multi-cylinder type buffer. In addition to being filled with the same liquid as that filled in the cylinder 1, the reservoir R is also filled with gas. Furthermore, when the liquid is hydraulic oil, the gas filled in the reservoir R can be an inert gas such as nitrogen to prevent the hydraulic oil from deteriorating. Additionally, in cylinder 1 Figure 1 A first partition wall 15 is installed on the lower end side facing the compression chamber R2, in the cylinder 1 Figure 1 A second partition wall 20, placed at the bottom of the outer cylinder 4 and with its outer peripheral side facing the liquid storage chamber R, is fitted into the lower middle part. The first partition wall 15 and the second partition wall 20 divide the compression side chamber R2 and the liquid storage chamber R, and these first partition walls 15 and second partition walls 20 constitute the partition wall component W. The first partition wall 15 and the second partition wall 20 are axially separated in the cylinder 1, dividing the intermediate chamber R3, which is filled with liquid inside the cylinder 1 and between the first partition wall 15 and the second partition wall 20. Additionally, in cylinder 1 Figure 1 At the upper middle end, a guide 5 is fitted to support the piston rod 2, allowing it to slide freely. This guide 5 is fitted into the inner circumference of the outer cylinder 4 and, by pressing against the upper end of the outer cylinder 4, is fixed to the outer cylinder 4 together with the sealing member 6. The sealing member 6 is deposited on the guide 5. Figure 1 The outer cylinder 4, cylinder 1, and piston rod 2 are sealed together at the top center. Thus, after the guide 5 is fixed to the outer cylinder 4, the cylinder 1 is held between the guide 5 and the second spacer wall 20 located at the bottom of the outer cylinder 4, and the cylinder 1 is also fixed inside the outer cylinder 4 together with the second spacer wall 20. Alternatively, instead of pressing the upper opening of the outer cylinder 4, a cap can be screwed onto the upper opening, and the sealing component 6, guide 5, cylinder 1, and second spacer wall 20 are held between the cap and the bottom of the outer cylinder 4, thus fixing these components inside the outer cylinder 4. The piston rod 2 is cylindrical with a reduced outer diameter at the front end, and includes a piston fitting portion 2a with the smallest diameter at the front end, and a portion with an outer diameter larger than that of the piston fitting portion 2a located at the piston fitting portion 2a. Figure 2 The upper-middle large-diameter portion 2b, the stepped portion 2c provided at the boundary between the piston fitting portion 2a and the large-diameter portion 2b, and the threaded portion (not shown) provided on the outer periphery of the front end of the piston fitting portion 2a. Moreover, in piston rod 2 Figure 1A bracket (not shown) is provided at the upper base end, and the piston rod 2 is connected to one of the vehicle body and the wheel via the bracket (not shown). In addition, a bracket (not shown) is also provided at the bottom of the outer cylinder 4, and the outer cylinder 4 is connected to the other of the vehicle body and the wheel via the bracket (not shown). Thus, the buffer D is installed between the vehicle body and the wheel. Moreover, when the vehicle travels on uneven roads or other surfaces that cause the wheel to vibrate up and down relative to the vehicle body, the piston rod 2 moves in and out of the outer cylinder 4 to extend and retract the buffer D, and the piston 3 moves up and down (axially) within the cylinder 1. Piston 3 is ring-shaped, such as Figure 1 As shown, the piston 3 has an elongated side piston port 3a that connects the elongated side chamber R1 and the compression side chamber R2, and a compression side piston port 3b that connects the compression side chamber R2 and the elongated side chamber R1. In the piston 3... Figure 1 A ring-shaped compression-side check valve 8 is superimposed on the upper middle part of the piston 3. Figure 1 An annular extension-side main valve 7 is superimposed on the lower center. Furthermore, the compression-side check valve 8, piston 3, and extension-side main valve 7 are sequentially fitted into the outer periphery of the piston fitting portion 2a of the piston rod 2, and are fixed to the piston rod 2 by the piston nut 9, which is threaded into the threaded portion at the front end of the piston rod 2 (not shown in the figure), and the stepped portion 2c. The extended-side main valve 7 is a laminated vane valve composed of multiple stacked annular plates, and overlaps with the piston 3. Figure 1 On the lower compression chamber side, the outlet end of the elongation piston port 3a is opened and closed. Additionally, a throttling orifice 7a, formed by a cut (not shown), is provided on the outer periphery of the annular plate where the elongation main valve 7 abuts against the piston 3. Furthermore, the throttling orifice 7a can be formed by a recess on a valve seat (not shown) surrounding the elongation piston port 3a in the piston 3, provided by engraving or the like, or it can be provided on a valve seat (not shown) where the compression check valve 8 or the compression check valve 8 is located. Furthermore, the inner circumference of the extension-side main valve 7 is fixed to the piston rod 2, allowing bending of the outer circumference. When the pressure in the extension-side chamber R1 is higher than the pressure in the compression-side chamber R2, and the pressure difference between the two reaches the valve opening pressure, the extension-side chamber R1, which operates through the extension-side piston port 3a, bends and opens the valve, connecting the extension-side chamber R1 and the compression-side chamber R2. Moreover, the extension-side main valve 7 applies resistance to the liquid flow through the extension-side piston port 3a, causing the pressure in the extension-side chamber R1 to rise. Conversely, when the pressure in the compression chamber R2 is higher than the pressure in the extension chamber R1, the extension-side main valve 7 is pushed against the piston 3 by the pressure from the compression chamber R2, which operates from the rear side, thereby closing the extension-side piston port 3a. When the extension-side main valve 7 is closed, the extension-side piston port 3a is in a state where it is connected to the compression chamber R2 only through the throttle orifice 7a. Furthermore, the number of stacked plates of the annular plate in the extended-side main valve 7 can be arbitrarily changed according to the required damping force. In addition, the extended-side main valve 7 is set as a vane valve, but it can also be a valve other than a vane valve as long as it can apply resistance to the liquid flow through the second compression side port 20d. On the other hand, the compression-side check valve 8 is constructed by having an annular plate that can move axially away from or towards the piston 3, and a spring that applies force to the annular plate towards the piston 3, and serves as the piston 3. Figure 1 The extended side chambers overlap on the upper side, opening and closing the outlet end of the compression side piston port 3b. When the pressure in the compression side chamber R2 is higher than the pressure in the extended side chamber R1, and the compression side check valve 8 is separated from the piston 3 by the pressure of the compression side chamber R2 acting via the compression side piston port 3b, the compression side check valve 8 opens the compression side piston port 3b, allowing the compression side chamber R2 to communicate with the extended side chamber R1. Furthermore, the compression side check valve 8 applies minimal resistance when opening, allowing liquid to pass through the compression side piston port 3b. Conversely, when the pressure in the extended side chamber R1 is higher than the pressure in the compression side chamber R2, the compression side check valve 8 is pushed against the piston 3 by the pressure of the extended side chamber R1 acting from the rear side, thereby closing the compression side piston port 3b and cutting off the communication between the compression side chamber R2 and the extended side chamber R1. Next, the compression-side main valve 11, the compression-side auxiliary valve 13, the extension-side auxiliary valve 12, and the suction check valve 14 will be described. For example... Figure 2 As shown, the compression-side main valve 11 and the suction check valve 14 are located in the second partition wall 20, and the compression-side auxiliary valve 13 and the extension-side auxiliary valve 12 are located in the first partition wall 15. The second partition wall 20 is installed on the cylinder 1 by being clamped between the bottom of the cylinder 1 and the outer cylinder 4. Figure 2 The lower part faces the liquid storage chamber R. The first partition wall 15 is disposed below the cylinder 1 and separated from the second partition wall 20, facing the compression side chamber R2, and forming an intermediate chamber R3 inside the cylinder 1 and between the first partition wall 1 and the second partition wall 20. Thus, the first partition wall 15 and the second partition wall 20 are disposed between the compression side chamber R2 and the liquid storage chamber R, separating the compression side chamber R2 and the liquid storage chamber R. More specifically, the second partition wall 20 includes: a partition wall body 20a, which is annular and fits into the inner circumference of the cylinder 1; and a flange portion 20b, which is annular and is attached to the partition wall body 20a. Figure 2 The middle and lower ends are connected, the outer diameter is larger than the outer diameter of the partition wall body 20a and the inner diameter is smaller than the outer diameter of the partition wall body 20a, and it is clamped between the lower end of the cylinder 1 and the bottom of the outer cylinder 4; and the second elongation side port 20c and the second compression side port 20d, which axially penetrate the partition wall body 20a. In addition, a second mounting shaft 21 is inserted into the inner circumference of the partition wall body 20a in the second partition wall 20, and a compression side main valve 11 and a suction check valve 14 are installed on the outer circumference of the second mounting shaft 21. The flange 20b in the second partition wall 20, from Figure 2 Multiple cuts 20e at the lower end are equally spaced in the circumferential direction to ensure communication between the gap in the flange 20b and the liquid storage chamber R. The second elongated side port 20c and the second compression side port 20d are both connected at one end to the intermediate chamber R3 between the first partition wall 15 and the second partition wall 20, and at the other end to the liquid storage chamber R through the gap in the flange portion 20b, thereby connecting the intermediate chamber R3 and the liquid storage chamber R. The compression-side main valve 11 is configured as a laminated blade valve consisting of multiple laminated annular plates, and the spacer body 20a in the second spacer wall 20... Figure 2 The lower side of the reservoir overlaps, opening and closing the outlet end of the second compression side port 20d. The inner circumference of the compression side main valve 11 is fixed to the second mounting shaft 21, allowing bending of the outer circumference. When the pressure in the intermediate chamber R3 is higher than the pressure in the reservoir R and the pressure difference between the two reaches the valve opening pressure, the valve is opened by the pressure of the intermediate chamber R3 acting through the second compression side port 20d, thus opening the second compression side port 20d and connecting the intermediate chamber R3 and the reservoir R. In addition, a throttling orifice 11a formed by a cut is provided on the outer circumference of the annular plate of the compression side main valve 11 that abuts against the second partition wall 20. Furthermore, the throttling orifice 11a can be formed by a recess provided on the valve seat of the second compression side port 20d surrounding the second partition wall 20 by engraving or the like, or it can be provided on a valve seat not shown in the figure where the suction check valve 14 or the suction check valve 14 is located. Thus, the compression-side main valve 11 resists the liquid flow through the second compression-side port 20d, causing the pressure in the intermediate chamber R3 to rise. Conversely, when the pressure in the reservoir R is higher than the pressure in the intermediate chamber R3, the compression-side main valve 11 is pushed against the piston 3 by the pressure of the reservoir R, which acts from the rear side, thus closing the second compression-side port 20d. When the compression-side main valve 11 is closed, the second compression-side port 20d is in a state where it is only connected to the reservoir R through the throttle orifice 11a. Furthermore, the number of stacked plates of the annular plate in the compression-side main valve 11 can be arbitrarily changed according to the damping force. In addition, the compression-side main valve 11 is set as a vane valve, but it can also be a valve other than a vane valve as long as it can apply resistance to the liquid flow through the second compression-side port 20d. On the other hand, the suction check valve 14 is constructed by including an annular plate that can move axially away from or towards the second spacer wall 20 and a spring that applies force to the annular valve body towards the second spacer wall 20, and is part of the spacer wall body 20a in the second spacer wall 20. Figure 2 The upper middle chamber overlaps, opening and closing the outlet end of the second extended side port 20c. When the pressure in the reservoir R is higher than the pressure in the middle chamber R3, and the reservoir R, acting via the second extended side port 20c, is separated from the second partition wall 20 and bends to open, the suction check valve 14 opens the second extended side port 20c, connecting the reservoir R to the middle chamber R3. Furthermore, the suction check valve 14 applies minimal resistance when opening, allowing liquid to pass through the second extended side port 20c. Conversely, when the pressure in the middle chamber R3 is higher than the pressure in the reservoir R, the suction check valve 14 is pushed against the second partition wall 20 by the pressure of the middle chamber R3 acting from the rear side, thereby closing the second extended side port 20c and cutting off the connection between the middle chamber R3 and the reservoir R. The compression-side main valve 11 and the suction check valve 14, configured in this manner, are fitted together with the second spacer 20 onto the outer periphery of the second mounting shaft 21. The second mounting shaft 21 includes a shaft portion 21a that inserts into the inner periphery of the second spacer 20, the compression-side main valve 11, and the suction check valve 14, and a [missing information - likely a component or element] provided on the shaft portion 21a. Figure 2 The flange 21b at the lower middle end, and the flange at the front end of the shaft portion 21a Figure 2 The upper and middle threaded portion 21c. Furthermore, the second mounting shaft 21 holds the second spacer 20, the compression-side main valve 11, and the suction check valve 14, which are fitted on the outer periphery of the shaft portion 21a, through the flange 21b and the nut 22 threadedly engaged with the threaded portion 21c, and retains the inner periphery of the second spacer 20, the compression-side main valve 11, and the suction check valve 14. The first partition wall 15 is installed below the cylinder 1 and spaced upward from the second partition wall 20. Specifically, the first partition wall 15 is annular and has an axially extending first elongated side port 15a and a first compression side port 15b, as well as an annular groove 15e disposed on the outer periphery along the circumferential direction. Moreover, the first partition wall 15 is fixed to the cylinder 1 by inserting a pressing part 1a, which is plastically deformed by pressing the cylinder 1 from the outer periphery, into the annular groove 15e. In addition, by inserting the pressing part 1a into the annular groove 15e in this way, the first partition wall 15 and the cylinder 1 are sealed, preventing the compression side chamber R2 and the intermediate chamber R3 from being connected to the cylinder 1 through the first partition wall 15. As described above, the first partition wall 15 is disposed below the cylinder 1 and spaced apart from the second partition wall 20, facing the compression side chamber R2, and forming an intermediate chamber R3 inside the cylinder 1 and between it and the second partition wall 20. In addition, a first mounting shaft 16 is inserted into the inner circumference of the first partition wall 15, and an extension side auxiliary valve 12 and a compression side auxiliary valve 13 are installed on the outer circumference of the first mounting shaft 16. like Figure 3 As shown, the first elongated side port 15a and the first compression side port 15b are arranged alternately in the circumferential direction relative to the first spacer wall 15, with three sets of each. One end of each of the first elongated side port 15a and the first compression side port 15b is connected to the compression side chamber R2, which is located above the first spacer wall 15, and the other end is connected to the intermediate chamber R3 between the first spacer wall 15 and the second spacer wall 20, thus connecting the compression side chamber R2 and the intermediate chamber R3. Additionally, on the compression side of the first partition wall 15... Figure 2 At the upper middle end, a petal-shaped extended side valve seat 15c, surrounding the outlet end of the first extended side port 15a, protrudes towards the compression side chamber side, on the middle chamber side of the first spacer wall 15. Figure 2 At the lower middle end, the petal-shaped compression side valve seat 15d, which surrounds the outlet end of the first compression side port 15b, is arranged protruding towards the middle chamber side. The extended-side secondary valve 12 includes: an extended-side valve body 12a, which is annular and can axially move away from or towards the first spacer wall 15, and is located in the first spacer wall 15. Figure 2The compression chamber at the upper middle end overlaps; and the elongation spring 12b applies force to the elongation valve body 12a against the first partition wall 15. The elongation valve body 12a has an annular valve portion 12a1 that is seated / removed from the elongation valve seat 15c, and an annular guide portion 12a2 that extends from the inner circumference of the valve portion 12a1 toward the opposite side of the first partition wall. When it abuts against the elongation valve seat 15c, it is in close contact with the elongation valve seat 15c without gap, thus sealing the first elongation port 15a without gap. When it is separated from the elongation valve seat 15c, the first elongation port 15a can be opened. Furthermore, the extended-side valve body 12a is mounted such that the inner circumference of the guide portion 12a2 slides into contact with the outer circumference of the cylindrical collar 17, which is fitted onto the outer circumference of the first mounting shaft 16, and is axially movable relative to the first mounting shaft 16. Thus, the extended-side valve body 12a is guided axially by the collar 17 and can move away from or closer to the first spacer wall 15. The collar 17 stands upright from the first spacer wall 15 and functions as a central rod inserted into the inner circumference of the extended-side valve body 12a; the outer diameter of the collar 17 is smaller than the outer diameter of the piston fitting portion 2a of the piston rod 2. The inner diameter of the extended-side valve body 12a, which slides into contact with the outer circumference of the collar 17, is smaller than the inner diameter of the stacked vane valve constituting the compression-side main valve 11 mounted on the outer circumference of the piston fitting portion 2a. Additionally, the inner diameter of the extended-side valve body 12a is smaller than the inner diameter of the stacked vane valve constituting the compression-side main valve 11 mounted on the outer circumference of the piston fitting portion 2a. The compression-side auxiliary valve 13 includes: a compression-side valve body 13a, which is annular and can axially move away from or towards the first spacer wall 15, and is located in the first spacer wall 15. Figure 2 The middle chamber side overlaps at the lower end; and the compression side spring 13b applies force to the compression side valve body 13a against the first partition wall 15. The compression side valve body 13a has an annular valve portion 13a1 that is seated / removed from the compression side valve seat 15d, and an annular guide portion 13a2 that extends from the inner circumference of the valve portion 13a1 to the opposite side of the first partition wall. When it abuts against the compression side valve seat 15d, it is in close contact with the compression side valve seat 15d without gap, thus closing the first compression side port 15b. When it is separated from the compression side valve seat 15d, the first compression side port 15b can be opened. Furthermore, the compression-side valve body 13a is mounted such that the inner circumference of the guide portion 13a2 slides in contact with the outer circumference of the cylindrical collar 18 fitted onto the outer circumference of the first mounting shaft 16, and is axially movable relative to the first mounting shaft 16. Thus, the compression-side valve body 13a is guided axially by the collar 18 and can move away from or closer to the first spacer wall 15. The collar 18 stands upright from the first spacer wall 15 and functions as a central rod inserted into the inner circumference of the compression-side valve body 13a; the outer diameter of the collar 18 is smaller than the outer diameter of the shaft portion 21a of the second mounting shaft 21 on which the compression-side main valve 11 is mounted. Therefore, the inner diameter of the compression-side valve body 13a, which slides in contact with the outer circumference of the collar 18, is smaller than the inner diameter of the stacked vane valve constituting the compression-side main valve 11 mounted on the outer circumference of the piston fitting portion 2a. The first mounting shaft 16 includes a first spacer 15, a collar 17, 18, an extension-side auxiliary valve 12, a compression-side auxiliary valve 13, a shaft portion 16a inserted into the inner circumference of the spring bracket 19, and a [missing information - likely a component or element] provided on the shaft portion 16a. Figure 2 The upper flange 16b and the shaft portion 16a Figure 2 The lower end is formed by pressing together the rim. Furthermore, the first mounting shaft 16 uses the flange 16b and the rim 16c to clamp and hold the collar 17, the first spacer 15, the collar 18, and the spring bracket 19, which are fitted onto the outer periphery of the shaft portion 16a, thus maintaining these components. Therefore, the collar 17, the first spacer 15, the collar 18, and the spring bracket 19 are fixedly and permanently to the outer periphery of the shaft portion 16a of the first mounting shaft 16. Furthermore, the guide portion 12a2 of the elongated side valve body 12a in the elongated side auxiliary valve 12 slides on the outer periphery of the collar 17, allowing the elongated side valve body 12a to move axially relative to the collar 17 held in the shaft portion 16a. The elongated side spring 12b is located on the outer periphery of the collar 17 and is installed between the valve portion 12a1 and the flange 16b of the elongated side valve body 12a, always applying force towards the first spacer wall 15 to the elongated side valve body 12a. Additionally, the elongated side spring 12b is a conical helical spring with a short contact length, thus easily ensuring the stroke length of the elongated side valve body 12a relative to the first spacer wall 15 even when the overall length of the elongated side auxiliary valve 12 is shortened. However, it could also be a cylindrical helical spring, a wave washer, or other elastic bodies. The spring constant of the extension side spring 12b is relatively small. In addition, the force exerted by the extension side spring 12b on the extension side valve body 12a when it is seated on the first partition wall 15 is also relatively small. When the valve is opened, the extension side valve body 12a is separated from the first partition wall 15 by a greater distance. The spring bracket 19 has a cylindrical portion 19a that fits into the outer periphery of the shaft portion 16a, and an annular seat portion 19b that protrudes from the lower end of the cylindrical portion 19a toward the outer periphery in the diametrical direction. It overlaps below the collar 18 and is mounted on the first mounting shaft 16. Furthermore, on the outer periphery of the collar 18, the guide portion 13a2 of the compression-side valve body 13a in the compression-side auxiliary valve 13 slides in contact, allowing the compression-side valve body 13a to move axially relative to the collar 18 held in the shaft portion 16a. The compression-side spring 13b is located on the outer periphery of the collar 18 and is installed between the valve portion 13a1 of the compression-side valve body 13a and the seat portion 19b of the spring support 19, consistently applying force to the compression-side valve body 13a towards the first spacer wall 15. Additionally, the compression-side spring 13b is a conical helical spring with a short contact length, thus easily ensuring the stroke length of the compression-side valve body 13a relative to the first spacer wall 15 even when the overall length of the compression-side auxiliary valve 13 is shortened. However, it could also be a cylindrical helical spring, a wave washer, or other elastic bodies. The compression spring 13b has a small spring constant. In addition, the force exerted by the compression spring 13b on the compression valve body 13a when it is seated on the first partition wall 15 is also small. When the valve is opened, the compression valve body 13a is separated from the first partition wall 15 by a large distance. Furthermore, when the buffer D extends, if the compression chamber R2 is depressurized, the extension-side auxiliary valve 12, configured as described above, is separated from the first partition wall 15 by the pressure of the intermediate chamber R3, and opens the first extension-side port 15a by leaving the extension-side valve seat 15c. When the buffer D extends, the pressure of the intermediate chamber R3 is also depressurized, so the suction check valve 14 provided on the second partition wall 20 also opens, opening the second extension-side port 20c. Conversely, when the buffer D contracts, the extension-side auxiliary valve 12 is pushed against the first partition wall 15 by the pressure of the compression chamber R2 and sits on the extension-side valve seat 15c, thereby cutting off the first extension-side port 15a. The suction check valve 14 provided on the second partition wall 20 is also closed by the pressure of the pressurized intermediate chamber R3, thereby cutting off the second extension-side port 20c. Therefore, the extension side auxiliary valve 12 and the suction check valve 14 are connected in series between the compression side chamber R2 and the liquid storage chamber R, with the liquid storage chamber R as the upstream. The extension-side auxiliary valve 12 and the extension-side main valve 7 open when the buffer D extends. However, the opening pressure of the extension-side auxiliary valve 12 is lower than that of the extension-side main valve 7. When the buffer D extends or retracts, the extension-side auxiliary valve 12 opens earlier than the extension-side main valve 7. Furthermore, the compression-side auxiliary valve 13 is separated from the first partition wall 15 by the pressure of the compression-side chamber R2, which increases during the contraction of the buffer D, and opens the first compression-side port 15b by disengaging from the compression-side valve seat 15d. When the buffer D contracts, the pressure in the intermediate chamber R3 increases, and the differential pressure between it and the reservoir R reaches the opening pressure of the compression-side main valve 11, at which point the compression-side main valve 11 also opens, opening the second compression-side port 20d. Conversely, when the buffer D contracts, the compression-side auxiliary valve 13 is pushed against the first partition wall 15 by the pressure of the intermediate chamber R3 and sits on the compression-side valve seat 15d, thus cutting off the first compression-side port 15b. The compression-side main valve 11, located in the second partition wall 20, also closes due to the pressure of the reservoir R caused by the decompression of the intermediate chamber R3, thereby cutting off the second compression-side port 20d. Therefore, the compression-side auxiliary valve 13 and the compression-side main valve 11 are connected in series between the compression-side chamber R2 and the liquid storage chamber R, with the compression-side chamber R2 as the upstream. The compression-side auxiliary valve 13 and the compression-side main valve 11 open when the buffer D contracts. However, the opening pressure of the compression-side auxiliary valve 13 is lower than that of the compression-side main valve 11. When the buffer D contracts, the compression-side auxiliary valve 13 opens earlier than the compression-side main valve 11. The operation of the buffer D constructed as described above will be explained. First, the piston 3 moves relative to the cylinder 1... Figure 1 The action of the buffer D, which moves to the upper middle side, during its extension motion will be explained. When piston 3 is relative to cylinder 1 Figure 1 As the piston 3 moves upwards, the elongation chamber R1 shrinks and the compression chamber R2 expands. During the extension action of the buffer D, the piston 3's speed relative to the cylinder 1 is within a very low speed range. The pressure difference between the elongation chamber R1 and the compression chamber R2 does not reach the opening pressure of the elongation main valve 7. Therefore, the elongation main valve 7 remains closed and does not bend. Consequently, the liquid in the shrinking elongation chamber R1 moves to the compression chamber R2 through the elongation piston port 3a and the throttle orifice 7a. Because the piston speed is within a very low speed range, the flow rate of the liquid through the throttle orifice 7a is extremely small, therefore the resistance exerted by the throttle orifice 7a on the liquid flow is also extremely small. During the extension of buffer D, piston rod 2 moves towards... Figure 1As the piston rod 2 moves upward and exits from cylinder 1, the volume pushed open by the piston rod 2 in cylinder 1 decreases, resulting in a lack of liquid in cylinder 1 due to the volume of liquid ejected by the piston rod 2. Consequently, the suction check valve 14 opens, connecting the reservoir chamber R and the intermediate chamber R3 through the second extended side port 20c, and the extended side auxiliary valve 12 opens, connecting the intermediate chamber R3 and the compression chamber R2 through the first extended side port 15a. Furthermore, the extended side auxiliary valve 12 applies resistance to the liquid flow through the first extended side port 15a, thus reducing the pressure in the compression chamber R2 to below that in the extended side chamber R1. Therefore, when the buffer D extends and the piston speed is in a very low range, such as Figure 4 As shown, the resistance applied to the flow of liquid by the extension side auxiliary valve 12 generates a damping force that hinders the extension action of the buffer D. The damping force characteristic, which is a characteristic of the damping force relative to the piston speed, is that the damping coefficient is high and the damping force increases rapidly with the increase of the piston speed. Furthermore, since the amount of liquid flowing through the extension-side auxiliary valve 12 is equal to the volume of the piston rod 2 exiting the cylinder 1, the amount of liquid flowing through can be reduced compared to the case where the extension-side auxiliary valve 12 is located in the piston section. Additionally, even in the case of a multi-cylinder type damper D where the outer diameter of the cylinder 1 cannot be increased, the difference between the inner and outer diameters of the extension-side auxiliary valve 12 can be increased because it is located on the outer periphery of the collar 17, whose diameter is smaller than the outer diameter of the piston fitting portion 2a of the piston rod 2. Therefore, even in the case of a multi-cylinder type damper D where the outer diameter of the cylinder 1 cannot be increased, the resistance exerted by the extension-side auxiliary valve 12 on the flow of liquid after opening is smaller than when the extension-side auxiliary valve is located in the piston section, and the damping force is not excessive. Subsequently, when the piston speed during the extension action of the buffer D exceeds the low-speed range and enters the low-speed range, the pressure difference between the extension-side chamber R1 and the compression-side chamber R2 increases, but it has not yet reached the opening pressure of the extension-side main valve 7. Therefore, the extension-side main valve 7 does not bend and remains closed. The liquid in the reduced extension-side chamber R1 moves to the compression-side chamber R2 through the extension-side piston port 3a and the throttling orifice 7a. When the piston speed enters the low-speed range, the flow rate of the liquid flowing through the throttling orifice 7a increases, thus increasing the resistance exerted by the throttling orifice 7a on the liquid flow. When the piston speed is in the low-speed range during the extension action of the buffer D, both the suction check valve 14 and the extension side auxiliary valve 12 are open. However, since the extension side valve body 12a of the extension side auxiliary valve 12 is far away from the first partition wall 15, the resistance exerted by the extension side auxiliary valve 12 on the flow of liquid is smaller than the resistance exerted by the throttle orifice 7a on the flow of liquid. Therefore, when the buffer D extends and the piston speed is in a low-speed range, such as Figure 4 As shown, the damping force that hinders the extension of the buffer D is mainly generated by the resistance exerted on the liquid flow by the throttling orifice 7a. Therefore, when the buffer D extends and the piston speed is in the low-speed range, the buffer D generates a damping force that is proportional to the square of the piston speed unique to the throttling orifice. The damping force characteristic is that the damping coefficient is lower than that in the very low-speed range. Furthermore, when the piston speed during the extension action of the buffer D exceeds the low speed range and becomes the high speed range, the pressure difference between the extension side chamber R1 and the compression side chamber R2 increases and exceeds the opening pressure of the extension side main valve 7. The liquid in the shrinking extension side chamber R1 pushes open the extension side main valve 7 and moves towards the compression side chamber R2 through the extension side piston port 3a. When the piston speed is in the high-speed range during the extension action of the buffer D, both the suction check valve 14 and the extension side auxiliary valve 12 are open. However, since the extension side valve body 12a of the extension side auxiliary valve 12 is far away from the first partition wall 15, the resistance exerted by the extension side auxiliary valve 12 on the flow of liquid is smaller than the resistance exerted by the extension side main valve 7 on the flow of liquid. Therefore, when the buffer D extends and the piston speed is in the high-speed range, such as Figure 4 As shown, the damping force that hinders the extension of the buffer D is mainly generated by the resistance exerted on the liquid flow by the main valve 7 on the extension side. Therefore, when the buffer D extends and the piston speed is in the high-speed range, the damping force characteristic is that the damping coefficient is lower than at low speed, but the damping force increases approximately linearly with the piston speed. Subsequently, the piston 3 is directed relative to the cylinder 1. Figure 1 The action of the buffer D, which moves to the lower middle side, during its retraction motion will be explained. When piston 3 is relative to cylinder 1 Figure 1 As the piston 3 moves downwards, the compression chamber R2 shrinks and the extension chamber R1 expands. When the buffer D contracts, the compression check valve 8 opens, allowing the liquid in the shrinking compression chamber R2 to move through the compression piston port 3b to the extension chamber R1 with minimal resistance. During the contraction of the buffer D, the piston rod 2 enters the cylinder 1, resulting in an excess of liquid within the cylinder 1. This excess liquid then moves from the cylinder 1 to the reservoir R. During the contraction of the buffer D, the piston speed is within a very low speed range. The pressure difference between the compression chamber R2 and the reservoir R is small, but the compression-side auxiliary valve 13 opens, opening the first compression-side port 15b. Liquid in the compression chamber R2 moves towards the intermediate chamber R3. On the other hand, during the contraction of the buffer D, the piston speed is within a very low speed range. The pressure difference between the compression chamber R2 and the reservoir R is small, and the pressure difference between the intermediate chamber R3 and the reservoir R does not reach the opening pressure of the compression-side main valve 11. Therefore, the compression-side main valve 11 does not bend and remains closed. Liquid in the intermediate chamber R3 moves towards the reservoir R through the throttling orifice 11a and the second compression-side port 20d. Because the piston speed is within a very low speed range, the flow rate of liquid through the throttling orifice 11a is extremely small, therefore the resistance exerted by the throttling orifice 11a on the liquid flow is also extremely small. Therefore, during the contraction of the buffer D, the piston speed is within a very low range. The compression-side auxiliary valve 13 opens, applying resistance to the liquid flow through the first compression-side port 15b. Consequently, the pressure in the compression-side chamber R2 and the extension-side chamber R1 increases. The pressure-bearing area of ​​the compression-side chamber of piston 3 is only slightly larger than the cross-sectional area of ​​piston rod 2 compared to the pressure-bearing area of ​​the extension-side chamber of piston 3. Therefore, as the pressure in the compression-side chamber R2 and the extension-side chamber R1 increases, the force pushing piston 3 increases, which becomes a damping force that hinders the contraction of the buffer D. Therefore, when the buffer D contracts and the piston speed is in a very low range, such as Figure 4 As shown, the resistance applied to the flow of liquid by the compression side auxiliary valve 13 generates a damping force that hinders the contraction action of the buffer D. The damping force characteristic, which is a characteristic of the damping force relative to the piston speed, is that the damping coefficient is high and the damping force increases rapidly with the increase of the piston speed. Furthermore, since the amount of liquid passing through the compression-side auxiliary valve 13 is equal to the volume of the piston rod 2 entering the cylinder 1, the amount of liquid passing through can be reduced compared to the case where the compression-side auxiliary valve 13 is located in the piston section. Additionally, even in the case of a multi-cylinder type damper D where the outer diameter of the cylinder 1 cannot be increased, the difference between the inner and outer diameters of the compression-side auxiliary valve 13 can be increased because it is located on the outer periphery of the collar 18, whose diameter is smaller than the outer diameter of the piston fitting portion 2a of the piston rod 2. Therefore, even in the case of a multi-cylinder type damper D where the outer diameter of the cylinder 1 cannot be increased, the resistance exerted by the compression-side auxiliary valve 13 on the flow of liquid after opening is smaller than when an extended auxiliary valve is provided in the piston section, and the damping force is not excessive. Subsequently, when the piston speed during the contraction action of the buffer D exceeds the low-speed range and enters the low-speed range, the pressure difference between the compression-side chamber R2 and the reservoir R increases, but it has not yet reached the opening pressure of the compression-side main valve 11. Therefore, the compression-side main valve 11 does not bend and remains closed. The liquid in the reduced compression-side chamber R2 moves towards the reservoir R through the first compression-side port 15b, the second compression-side port 20d, and the throttling orifice 11a. When the piston speed enters the low-speed range, the flow rate of the liquid flowing through the throttling orifice 11a increases, thus increasing the resistance exerted by the throttling orifice 11a on the liquid flow. When the piston speed is in the low-speed range during the contraction action of the buffer D, the compression side valve body 13a of the compression side auxiliary valve 13 is far away from the first partition wall 15. Therefore, the resistance exerted by the compression side auxiliary valve 13 on the flow of liquid is smaller than the resistance exerted by the throttle orifice 11a on the flow of liquid. Therefore, when the buffer D contracts and the piston speed is in a low-speed range, such as Figure 4 As shown, the damping force that hinders the contraction of the buffer D is mainly generated by the resistance exerted on the liquid flow by the throttling orifice 11a. Therefore, when the buffer D contracts and the piston speed is in the low-speed range, the buffer D generates a damping force that is proportional to the square of the piston speed unique to the throttling orifice. The damping force characteristic is that the damping coefficient is lower than that in the very low-speed range. Furthermore, when the piston speed during the contraction action of the buffer D exceeds the low-speed range and becomes the high-speed range, the pressure difference between the compression chamber R2 and the reservoir R increases and exceeds the opening pressure of the compression main valve 11. The liquid in the compression chamber R2 pushes open the compression main valve 11 and moves to the reservoir R through the second compression port 20d. When the piston speed is in the high-speed range during the contraction action of the buffer D, the compression-side auxiliary valve 13 opens. However, since the compression-side valve body 13a of the compression-side auxiliary valve 13 is far away from the first partition wall 15, the resistance exerted by the compression-side auxiliary valve 13 on the flow of liquid is smaller than the resistance exerted by the compression-side main valve 11 on the flow of liquid. Therefore, when the buffer D contracts and the piston speed is in the high-speed range, such as Figure 4 As shown, the damping force that hinders the contraction of the buffer D is mainly generated by the resistance exerted on the liquid flow by the main valve 11 on the compression side. Therefore, when the buffer D contracts and the piston speed is in the high-speed range, the damping force characteristic is that the damping coefficient is lower than that at low speed, but the damping force increases approximately linearly with the piston speed. 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, connected to the piston rod 2, which is axially movable and inserted into the cylinder 1 to divide the cylinder 1 into an elongated side chamber R1 and a compression side chamber R2 filled with liquid; an outer cylinder 4, which covers the outer periphery of the cylinder 1 and forms a liquid reservoir R between the outer cylinder 4 and the cylinder 1; an elongated side main valve 7, which applies resistance to the liquid flow from the elongated side chamber R1 toward the compression side chamber R2; and a compression side main valve 11 and a compression side auxiliary valve 13, which are connected in series between the compression side chamber R2 and the liquid reservoir R, to apply resistance to the liquid flow from the compression side chamber R1 toward the compression side chamber R2. The fluid flow from chamber R2 toward the reservoir R is resisted; the extension-side auxiliary valve 12, located between the reservoir R and the compression-side chamber R2, resists the fluid flow from the reservoir R toward the compression-side chamber R2; and the suction check valve 14, connected in series with the extension-side auxiliary valve 12 between the reservoir R and the compression-side chamber R2, allows only the fluid flow from the reservoir R toward the compression-side chamber R2; when the piston speed during the extension action is in a very low speed range, only the extension-side auxiliary valve 12 generates the damping force, and when the piston speed during the contraction action is in a very low speed range, only the compression-side auxiliary valve 13 generates the damping force. In the buffer D constructed in this manner, when the piston speed is in a very low speed range, damping force can be generated by the extended side auxiliary valve 12 or the compression side auxiliary valve 13 located between the compression side chamber R2 and the reservoir R, without the need to install the extended side auxiliary valve 12 and the compression side auxiliary valve 13 on the piston rod 2. It is difficult to reduce the diameter of the piston rod 2 to receive the lateral force input from a direction orthogonal to the axial direction relative to the buffer D. Consequently, it is difficult to increase the cylinder inner diameter in multi-cylinder buffers. Therefore, in conventional buffers, the difference between the inner and outer diameters of the vane valve in the damping valve cannot be increased. In contrast, in the buffer D of this embodiment, the extension-side auxiliary valve 12 or the compression-side auxiliary valve 13 is located between the compression-side chamber R2 and the reservoir R. This reduces the amount of liquid passing through during the extension and retraction of the buffer D. Furthermore, since it does not need to withstand lateral forces, there is no need to install the extension-side auxiliary valve 12 or the compression-side auxiliary valve 13 on the piston rod 2, whose outer diameter cannot be reduced in terms of strength. This increases the flow path area when the extension-side auxiliary valve 12 and the compression-side auxiliary valve 13 are open. Therefore, according to the buffer D of this embodiment, even in a multi-cylinder type, the damping force is not excessive when the piston speed is in the low-speed range, achieving good damping force characteristics and improving the ride comfort of the vehicle. Furthermore, since a compression-side main valve 11 and a compression-side auxiliary valve 13 are connected in series between the compression-side chamber R2 and the liquid storage chamber R, and an extension-side auxiliary valve 12 and a suction check valve 14 are connected in series between the liquid storage chamber R and the compression-side chamber R2, it is not necessary to use a structure where the compression-side auxiliary valve 13 bypasses the compression-side main valve 11 and the extension-side auxiliary valve 12 bypasses the extension-side main valve 7. The compression-side auxiliary valve 13 and the extension-side auxiliary valve 12 can be easily installed in the narrow cylinder 1 of the multi-cylinder buffer D, without causing the buffer D to become too large. Furthermore, the buffer D of this embodiment includes a spacer wall component W, which has a first spacer wall 15 and a second spacer wall 20 forming an intermediate chamber R3 between the first spacer wall 15 and the buffer wall 20, and divides a compression side chamber R2 and a liquid storage chamber R. The first spacer wall 15 has a first elongated side port 15a and a first compression side port 15b that connect the compression side chamber R2 and the intermediate chamber R3. The second spacer wall 20 has a second elongated side port 20c and a second compression side port 20d that connect the liquid storage chamber R and the intermediate chamber R3. An elongated side auxiliary valve 12 and a compression side auxiliary valve 13 are provided on the first spacer wall 15, and a compression side main valve 11 and a suction check valve 14 are provided on the second spacer wall 20. According to the buffer D constructed in this manner, if a first partition wall 15, which is equipped with an extension-side auxiliary valve 12 and a compression-side auxiliary valve 13, and a second partition wall 20, which is equipped with a compression-side main valve 11 and a suction check valve 14, are disposed between the compression-side chamber R2 and the reservoir chamber R, then the compression-side main valve 11 and the compression-side auxiliary valve 13 can be connected in series between the compression-side chamber R2 and the reservoir chamber R, and the extension-side auxiliary valve 12 and the suction check valve 14 can be connected in series between the reservoir chamber R and the compression-side chamber R2. Therefore, according to the buffer D constructed in this manner, the compression-side main valve 11, the extension-side auxiliary valve 12, the compression-side auxiliary valve 13, and the suction check valve 14 can be easily disposed, improving assemblability. Furthermore, as described above, the compression chamber R2 and the intermediate chamber R3 are divided by the first partition wall 15, and the liquid storage chamber R and the intermediate chamber R3 are divided by the second partition wall 20. However, the liquid storage chamber R and the intermediate chamber R3 can also be divided by the first partition wall 15, and the compression chamber R2 and the intermediate chamber R3 can be divided by the second partition wall 20. Therefore, the compression side main valve 11 and the compression side auxiliary valve 13 can be arranged in series between the compression side chamber R2 and the liquid storage chamber R, with the compression side main valve 11 arranged upstream and the compression side auxiliary valve 13 arranged downstream. Alternatively, the extension side auxiliary valve 12 can be arranged upstream and the suction check valve 14 can be arranged in series between the liquid storage chamber R and the compression side chamber R2, with the extension side auxiliary valve 12 arranged upstream and the suction check valve 14 arranged downstream. The extension-side auxiliary valve 12 and the compression-side main valve 11 can be provided in one of the first spacer wall 15 and the second spacer wall 20, and the compression-side auxiliary valve 13 and the suction check valve 14 can be provided in the other of the first spacer wall 15 and the second spacer wall 20. However, the existing multi-cylinder type buffer D is provided in the valve housing at the end of the cylinder 1 where the compression-side main valve 11 and the suction check valve 14 are installed. Therefore, if the valve housing is used as the second spacer wall 20, the buffer D of this embodiment can be realized simply by providing the first spacer wall 15 with the extension-side auxiliary valve 12 and the compression-side auxiliary valve 13 in the existing multi-cylinder type buffer. Therefore, it is advantageous in terms of minimizing cost or design changes. Furthermore, in this embodiment, the first partition wall 15 is fixed to the cylinder 1 by a pressing portion 1a formed from the outer periphery of the cylinder 1, such as... Figure 5 As shown, a second mounting shaft 23 can also be used to form a first mounting shaft and a second mounting shaft. The second partition wall 20 and the first partition wall 15 are connected by the mounting shaft 23. A sealing ring 24, which is installed in the annular groove 15e on the outer periphery of the first partition wall 1 and is tightly fitted to the inner periphery of the cylinder 1, seals the compression side chamber R2 and the intermediate chamber R3. In this way, the first partition wall 15, the second partition wall, the compression side main valve 11, the extension side auxiliary valve 12, the compression side auxiliary valve 13, and the suction check valve 14 are pre-assembled as a valve assembly. This valve assembly can be assembled onto the buffer D, further improving the assemblability of the buffer D. In addition, when the outer periphery of the first partition wall 15 is not in contact with the cylinder 1, a partition cylinder can be provided between the lower end of the first partition wall 15 and the upper end of the second partition wall 20. The intermediate chamber R3 is divided into the cylinder 1 within the partition cylinder and between the first partition wall 15 and the second partition wall 20. In addition, the partition cylinder can be separate from the first partition wall 15 and the second partition wall 20, or it can be integrally provided on the first partition wall 15 and the second partition wall 20. Furthermore, in the buffer D of this embodiment, the extension-side auxiliary valve 12 includes: an extension-side valve body 12a, which is annular and can move away from or closer to the first spacer wall 15, and when it abuts against the piston side end of the first spacer wall 15, it closes the first extension-side port 15a without gap; and an extension-side spring 12b, which applies force to the extension-side valve body 12a in the direction where it sits on the first spacer wall 15; the compression-side auxiliary valve 13 includes: a compression-side valve body 13a, which is annular and can move away from or closer to the first spacer wall 15, and when it abuts against the piston side end of the first spacer wall 15, it closes the first compression-side port 15b without gap; and a compression-side spring 13b, which applies force to the compression-side valve body 13a in the direction where it sits on the first spacer wall 15. According to the buffer D constructed in this way, the extension side auxiliary valve 12 and the compression side auxiliary valve 13 close the corresponding first extension side port 15a and first compression side port 15b without gap. Therefore, there is no throttling orifice or choke ring, and the damping force can be increased from the very low piston speed range. In addition, since the extension side valve body 12a and the compression side valve body 13a are either far away from or close to the first partition wall 15, the flow path area can be increased after the valve is opened. Therefore, when it is desired to release the damping force by the extension side main valve 7 and the compression side main valve 11, the extension side auxiliary valve 12 and the compression side auxiliary valve 13 will not have any effect. Furthermore, when the buffer D extends, the extension side auxiliary valve 12 will not cause poor suction of liquid in the cylinder 1. Furthermore, the elongated side valve body 12a and the compression side valve body 13a in the elongated side auxiliary valve 12 and the compression side auxiliary valve 13 can be leaf valves whose inner circumference is fixed to the first mounting shaft 16 and allows the outer circumference to be bent. Although not shown, as disclosed in Japanese Patent Application Laid-Open No. 2004-225834, they can also be carbon valves composed of inner and outer valve seats with different diameters, and an annular double-leaf valve in which the inner circumference of one end face is seated on the inner valve seat and the outer circumference of the other end face is seated on the outer valve seat. Alternatively, the elongation-side valve body 12a and the compression-side valve body 13a in the extension-side auxiliary valve 12 and the compression-side auxiliary valve 13 can also be valves as disclosed in Japanese Patent Application Laid-Open No. 2019-116902, which are annular and have one of their inner or outer circumferential sides fixed. For liquid flow from the compression-side chamber R2 towards the reservoir R, the other of the inner or outer circumferential sides bends towards the reservoir R to allow liquid flow, and for liquid flow from the reservoir R towards the compression-side chamber R2, the other of the inner or outer circumferential sides bends towards the compression-side chamber R2 to allow liquid flow. Thus, the elongation-side auxiliary valve 12 and the compression-side auxiliary valve 13 can be implemented by a single valve that can resist both liquid flow from the compression-side chamber R2 towards the reservoir R and liquid flow from the reservoir R towards the compression-side chamber R2. Furthermore, in the buffer D of this embodiment, the extension-side main valve 7 is an annular vane valve, and the inner diameter of the extension-side valve body 12a is smaller than the inner diameter of the extension-side main valve 7; or the compression-side main valve 11 is an annular vane valve, and the inner diameter of the compression-side valve body 13a is smaller than the inner diameter of the compression-side main valve 11. The buffer D constructed in this manner increases the difference between the inner and outer diameters of the annular elongated side valve body 12a or the compression side valve body 13a, ensuring a larger flow path area after valve opening. Therefore, there is no concern that the elongated side auxiliary valve 12 will generate a greater damping force than the elongated side main valve 7, or that the compression side auxiliary valve 13 will generate a greater damping force than the compression side main valve 11. Alternatively, the elongated side main valve 7 can be configured as an annular vane valve, with the inner diameter of the elongated side valve body 12a being smaller than the inner diameter of the elongated side main valve 7, and the compression side main valve 11 can be configured as an annular vane valve, with the inner diameter of the compression side valve body 13a being smaller than the inner diameter of the compression side main valve 11. In addition, in this embodiment, the collars 17 and 18 are used as central members, but the collars 17 and 18 can be omitted and the first mounting shaft 16 can be used as the central member, or the central member can be integrally provided on the first partition wall 15. 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.

[0095] Symbol Explanation 1 cylinder 2 piston rods 2a Piston Fitting Part 3-piston 4 outer barrel 7. Extended side main valve 11 Compression-side main valve 12-Extended Side Auxiliary Valve 12a elongated side valve body 12b elongation side spring 13 Compression Side Auxiliary Valve 13a Compression Side Valve Body 13b Compression side spring 14. Intake check valve 15 First partition wall 15a First elongated side port 15b First compression side port 20 Second partition wall 20a Second elongated side port 20b Second Compression Side Port D buffer Rreservoir R1 elongated side chamber R2 compression side chamber R3 Intermediate Chamber W spacer component

Claims

1. A buffer, comprising: cylinder; The piston rod is axially movable and inserted into the cylinder; A piston, connected to the piston rod, is axially movable and inserted into the cylinder to divide the cylinder into a liquid-filled elongation side chamber and a compression side chamber. An outer cylinder covers the outer periphery of the cylinder and forms a liquid storage chamber between itself and the cylinder; The extension-side main valve applies resistance to the fluid flow from the extension-side chamber toward the compression-side chamber; A compression-side main valve and a compression-side auxiliary valve are connected in series between the compression-side chamber and the liquid storage chamber to apply resistance to the liquid flow from the compression-side chamber toward the liquid storage chamber; An extension-side auxiliary valve is located between the liquid storage chamber and the compression-side chamber, and applies resistance to the liquid flow from the liquid storage chamber toward the compression-side chamber; as well as A suction check valve is connected in series with the extension side auxiliary valve between the liquid reservoir and the compression side chamber, allowing liquid flow only from the liquid reservoir toward the compression side chamber; When the piston speed is in a very low range during the extension action, the damping force is generated only by the extension-side auxiliary valve. When the piston speed is in the low-speed range during the contraction action, the damping force is generated only by the compression-side auxiliary valve.

2. The buffer according to claim 1, comprising: A partition wall component having a first partition wall and a second partition wall forming an intermediate chamber between the first partition wall and the second partition wall, dividing the compression side chamber and the liquid storage chamber; The first partition wall has a first elongated side port and a first compression side port that communicate one of the compression side chamber and the liquid storage chamber with the intermediate chamber. The second partition wall has a second elongated side port and a second compression side port that communicate with the intermediate chamber via the other of the compression-side chamber and the reservoir chamber. The extension-side auxiliary valve and the compression-side auxiliary valve are located in the first partition wall. The compression-side main valve and the suction check valve are located in the second partition wall.

3. The buffer according to claim 2, wherein, The extended-side auxiliary valve has: The extended side valve body is annular and can move away from or close to the first spacer wall as a whole. When it abuts against the piston side end of the first spacer wall, it seals the first extended side port without gaps. as well as The extension-side spring applies force to the extension-side valve body in the direction where it rests on the first partition wall; The compression-side auxiliary valve has: The compression-side valve body is annular and can move away from or closer to the first spacer wall. When it abuts against the piston side end of the first spacer wall, it seals the first compression-side port without gaps. as well as The compression-side spring applies force to the compression-side secondary valve in the direction it rests on the first partition wall.

4. The buffer according to claim 3, wherein, The extension-side main valve is an annular vane valve, and the inner diameter of the extension-side valve body is smaller than the inner diameter of the extension-side main valve; or the compression-side main valve is an annular vane valve, and the inner diameter of the compression-side valve body is smaller than the inner diameter of the compression-side main valve.

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