Damping valves and shock absorbers

Abstract

To provide an attenuation valve which can obtain an attenuation force characteristic which is favorable for suppressing elongation by exerting a sufficient attenuation force when a damper is elongated and contracted at an extremely-low speed, and the damper.SOLUTION: An attenuation valve V1 of the present invention comprises: a bulkhead body 2 having an annular external peripheral valve seat 2c which is formed into an annular shape, positioned in a radial direction by only a cylinder body while being inserted into the cylinder body 1, and protruding in an axial direction from one end 2b in the axial direction, and a port 2d arranged at an internal peripheral side of the external peripheral valve seat 2c; a valve stopper 3 opposing one end 2b of the bulkhead body 2, and having an annular internal peripheral valve seat 3c whose outside diameter is smaller than a diameter of the external peripheral valve seat 2c; and an annular leaf valve 4 interposed between the external peripheral valve seat 2c and the internal peripheral valve seat 3c, and set so as to open and close the port 2b in an inside / outside double-opening manner. The bulkhead body 2 comprises a core alignment part 2e for core-aligning the leaf valve 4 with respect to the external peripheral valve seat 2c.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] A shock absorber includes, for example, a cylinder, a piston movably inserted into the cylinder, and a piston rod also movably inserted into the cylinder and connected to the piston. The shock absorber is interposed between the vehicle body and the wheels to exert a damping force and suppress vibrations of the vehicle body and the wheels. The damping force exerted by the shock absorber is exerted by a damping valve, which affects the ride comfort in a vehicle. In recent years, in shock absorbers used in vehicle suspensions, it is desired to exert a sufficient damping force to suppress vibrations even when extending and contracting at an extremely low speed for improved ride comfort.

[0003] To meet such a demand, the damping valve may include a valve disk that is annular, loosely fitted around the outer periphery of the piston rod, axially movable, and has an outer valve seat surrounding the outer periphery of the port, a valve stopper fixed to the piston rod, axially opposed to the valve disk, annular, and having an inner valve seat with an outer diameter smaller than the inner diameter of the outer valve seat, and a leaf valve interposed between the outer valve seat and the inner valve seat and set to open both inward and outward (see, for example, Patent Document 1). Then, the damping valve exerts a damping force by applying resistance to the flow of the working oil passing through the port with the leaf valve when the shock absorber extends and contracts at a very low speed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a damping valve configured in this way, the valve disc is loosely fitted to the piston rod and slides against the inner circumference of the cylinder, which can cause radial misalignment with respect to the piston rod. On the other hand, a leaf valve is centered with respect to the piston rod, so if the valve disc becomes misaligned with respect to the piston rod, it will seat eccentrically on the outer valve seat provided on the valve disc.

[0006] If the leaf valve is seated eccentrically on the outer valve seat of the valve disc, the deflection of the leaf valve will not be uniform in the circumferential direction, and a gap may form between the leaf valve and the outer valve seat, even though the leaf valve is seated on the outer valve seat.

[0007] In such a situation, when the shock absorber expands and contracts at very low speeds, the hydraulic fluid passes through the gap created between the leaf valve and the outer valve seat, reducing the damping force. This makes it difficult to achieve the desired level of damping force, and the damping force characteristics (the characteristics of the damping force generated by the shock absorber in relation to the expansion and contraction speed of the shock absorber) that are good for suppressing vibrations when the shock absorber expands and contracts at very low speeds cannot be obtained.

[0008] Therefore, the present invention aims to provide a damping valve and a shock absorber that exhibit sufficient damping force even when the shock absorber expands and contracts at very low speeds, thereby obtaining good damping force characteristics for suppressing such expansion and contraction. [Means for solving the problem]

[0009] To solve the aforementioned problems, the damping valve of the present invention comprises a partition body which is annular in shape, inserted into a cylindrical body and positioned radially by the cylindrical body alone, and has an annular outer valve seat that protrudes axially from one end in the axial direction and a port provided on the inner circumference side of the outer valve seat, A rod inserted into the inner circumference of the partition wall, The valve stopper has an annular inner valve seat that faces one end of the partition wall and has an outer diameter smaller than the outer valve seat, and an annular leaf valve interposed between the outer valve seat and the inner valve seat to open and close the port and is set to open both inward and outward, the partition wall having an alignment portion that aligns the leaf valve with respect to the outer valve seat It has the ability to move radially relative to the rod. .

[0010] In a damping valve configured in this way, the leaf valve is centered relative to the outer valve seat by a centering part provided on a partition wall radially positioned by the cylindrical body alone. As a result, when the leaf valve is seated on the outer and inner valve seats, no gap is created between the outer circumference of the leaf valve and the outer valve seat, and no gap is created between the inner circumference of the leaf valve and the inner valve seat that would affect the damping force. Therefore, with a damping valve, liquid leakage through gaps can be prevented, and a sufficiently large damping force can be generated in the buffer even when the flow rate of liquid passing through the port is small.

[0011] Furthermore, the centering portion provided on the partition wall in the damping valve may be a projection that protrudes axially from the outer circumference of the outer valve seat at one end of the partition wall and abuts against the outer circumference of the leaf valve. With a damping valve configured in this way, if the centering portion is provided on a projection close to the outer valve seat, the centering accuracy of the leaf valve relative to the outer valve seat is improved.

[0012] Furthermore, the self-aligning portion provided on the partition wall in the damping valve may be a projection that protrudes axially from the inner circumference side of the port at one end of the partition wall and abuts against the inner circumference of the leaf valve. With a damping valve configured in this way, the outer diameter of the leaf valve can be made smaller than the outer diameter of the outer valve seat, improving the design freedom of the leaf valve.

[0013] Furthermore, the damping valve may be configured to include a main partition body inserted into the cylindrical body facing the partition body in the axial direction and equipped with a main port, and a main valve that opens and closes the main port and is set to a higher opening pressure than the leaf valve. With a damping valve configured in this way, the leaf valve can exert a damping force suitable for when the shock absorber expands and contracts at a very low speed, and the main valve can exert a large damping force when the expansion and contraction speed of the shock absorber becomes high speed. Therefore, with the damping valve of this embodiment, a damping force suitable for suppressing the expansion and contraction of the shock absorber can be generated in the shock absorber according to the expansion and contraction speed of the shock absorber.

[0014] Furthermore, the shock absorber comprises a cylinder, a piston rod inserted into the cylinder, and a damping valve, with the cylinder being a cylindrical body. With a shock absorber configured in this way, because it is equipped with a damping valve, sufficient damping force can be exerted even when expanding and contracting at very low speeds, and good damping force characteristics can be obtained for suppressing expansion and contraction. [Effects of the Invention]

[0015] Based on the above, the damping valve of the present invention exhibits sufficient damping force even when the shock absorber expands and contracts at very low speeds, resulting in good damping force characteristics for suppressing such expansion and contraction. The shock absorber of the present invention exhibits sufficient damping force even when expanding and contracting at very low speeds, resulting in good damping force characteristics for suppressing expansion and contraction. [Brief explanation of the drawing]

[0016] [Figure 1] This is a longitudinal cross-sectional view of a shock absorber equipped with a damping valve according to one embodiment. [Figure 2] This is an enlarged cross-sectional view of the piston portion of a shock absorber equipped with a damping valve in one embodiment. [Figure 3] This figure shows the damping force characteristics of a shock absorber equipped with a damping valve in one embodiment. [Figure 4] This is an enlarged cross-sectional view of the piston portion of a shock absorber equipped with a damping valve in one modified example of one embodiment. [Modes for carrying out the invention]

[0017] The present invention will be described below based on the embodiments shown in the figures. As shown in Figures 1 and 2, the damping valve V1 in one embodiment is configured to include a sub-piston 2 as a partition body which is annular and inserted into a cylinder 1 which is a cylindrical body and is positioned radially by the cylinder 1 alone, and which has an annular outer valve seat 2c and a port 2d, a valve stopper 3 which has an annular inner valve seat 3c facing one end 2b of the sub-piston 2, and an annular leaf valve 4 which is interposed between the outer valve seat 2c and the inner valve seat 3c and is set to open both inward and outward to open and close the port 2d, and is applied to a buffer D.

[0018] On the other hand, the shock absorber D to which the damping valve V1 is applied includes a cylinder 1, a piston rod 5 that is axially movably inserted into the cylinder 1, and a piston 6 as a main partition body that is attached to the piston rod 5 and axially inserted into the cylinder 1. move The shock absorber D further includes main valves 7 and 8 that open and close main ports 6a and 6b provided on the piston 6, and the damping valve V1. In the case of this shock absorber D, for example, it is interposed and used between the vehicle body and the axle of a vehicle (not shown) to suppress the vibrations of the vehicle body and wheels.

[0019] Hereinafter, each part of the damping valve V1 and the shock absorber D will be described in detail. As shown in FIG. 1, an annular rod guide 20 is attached to the upper end of the cylinder 1, and the lower end of the cylinder 1 is closed by a cap 14. A piston rod 5 with a piston 6 and a sub-piston 2 attached to its tip is movably inserted into the cylinder 1.

[0020] The piston rod 5 is slidably inserted into the rod guide 20 and axially movably inserted into the cylinder 1, and its axial movement is guided by the rod guide 20. The inside of the cylinder 1 is partitioned by the piston 6 and the sub-piston 2 into an extension chamber R1 and a compression chamber R2 filled with liquid. In this embodiment, the liquid is hydraulic oil, but other liquids such as water and aqueous solutions can also be used.

[0021] Note that in the cylinder 1, below the pressure chamber R2, an air chamber G is partitioned by a free piston 9 that is slidably inserted into the cylinder 1. When the piston rod 5 axially displaces with respect to the cylinder 1, the free piston 9 axially displaces with respect to the cylinder 1 and expands and contracts according to the volume change of the piston rod 5 in the cylinder 1, and the volume change of this air chamber G compensates for the volume of the piston rod 5 that enters and exits the cylinder 1. Thus, although the shock absorber D is a so-called single-cylinder type shock absorber, it may be configured as a double-cylinder type shock absorber having a reservoir outside the cylinder 1.

[0022] Returning, the piston rod 5 includes a small-diameter portion 5a provided at the tip that is the lower end in FIG. 1 thereof, a threaded portion 5b provided on the outer periphery of the tip of the small-diameter portion 5a, and a stepped portion 5c formed by providing the small-diameter portion 5a. An annular piston 6 and a sub-piston 2 are mounted on the outer periphery of the small-diameter portion 5a.

[0023] The piston 6 is annular and is fixed to the outer periphery of the small-diameter portion 5a, and its outer periphery is in sliding contact with the inner periphery of the cylinder 1. Further, the piston 6 includes a pressure-side main port 6a and an extension-side main port 6b as main ports. The sub-piston 2 has its outer periphery in sliding contact with the inner periphery of the cylinder 1 and includes a port 2d. The piston 6 and the sub-piston 2 are axially spaced apart and opposed to each other, and cooperate to partition the inside of the cylinder 1 into an extension chamber R1 and a pressure chamber R2, and an intermediate chamber R3 is formed between the piston 6 and the sub-piston 2. This intermediate chamber R3 is communicated with the pressure chamber R2 by the pressure-side main port 6a and the extension-side main port 6b provided in the piston 6, and is communicated with the extension chamber R1 by the port 2d provided in the sub-piston 2. Therefore, the pressure-side main port 6a, the extension-side main port 6b, the intermediate chamber R3, and the port 2d form a passage that communicates the extension chamber Rl and the pressure chamber R2.

[0024] As shown in Figures 1 and 2, a valve stopper 3, a leaf valve 4, a spacer 10, a cylindrical collar 11, a sub-piston 2, a main valve stopper 12, a compression-side main leaf valve 7 (which acts as the main leaf valve), a piston 6, and an extension-side main leaf valve 8 (which also acts as the main leaf valve) are mounted on the outer circumference of the small-diameter portion 5a of the piston rod 5. The valve stopper 3, spacer 10, collar 11, main valve stopper 12, compression-side main leaf valve 7, piston 6, and extension-side main leaf valve 8 are then held and fixed by a piston nut 13 that is screwed onto the stepped portion 5c and the threaded portion 5b of the piston rod 5.

[0025] As shown in Figure 2, the valve stopper 3 comprises an annular fitting portion 3a with a reduced inner diameter at the lower end in Figure 2, a flange portion 3b protruding outward from the outer circumference of the upper end in Figure 2 of the fitting portion 3a, and an annular inner valve seat 3c formed on the outer circumference of the lower end in Figure 2 that faces the sub-piston 2 of the flange portion 3b. The inner diameter of the fitting portion 3a at the lower end in Figure 2 is set to a diameter that fits the outer circumference of the small diameter portion 5a of the piston rod 5, while the inner diameter of the fitting portion 3a at the upper end in Figure 2 is larger than the outer diameter of the small diameter portion 5a of the piston rod 5 and the outer diameter of the upper part in Figure 2. Therefore, when the valve stopper 3 is fitted onto the small-diameter portion 5a of the piston rod 5, the inner circumference of the lower end of the fitting portion 3a fits onto the small-diameter portion 5a of the piston rod 5, positioning the valve stopper 3 radially relative to the piston rod 5, while the stepped portion at the boundary between the lower and upper ends of the fitting portion 3a abuts against the stepped portion 5c of the piston rod 5, positioning the valve stopper 3 axially relative to the piston rod 5.

[0026] In this embodiment, the spacer 10 is composed of multiple annular plates whose outer diameter is larger than the outer diameter of the collar 11 and whose inner diameter is set to a diameter that can be fitted into the small diameter portion 5a of the piston rod 5, and is fitted to the outer circumference of the small diameter portion 5a of the piston rod 5. By adjusting the number of stacked annular plates that make up the spacer 10, it is possible to adjust the axial position of the collar 11 relative to the piston rod 5 and the position of the upper limit of movement of the sub-piston 2 in Figure 2. Therefore, if adjustment of the position of the collar 11 is unnecessary and the movement limit of the sub-piston 2 is restricted by the fitting portion 3a of the valve stopper 3, the spacer 10 can be omitted, and depending on the position of the collar 11, it may be composed of a single annular plate.

[0027] The collar 11 is a cylindrical component whose outer diameter is smaller than the outer diameter of the fitting portion 3a of the spacer 10 and the valve stopper 3, and whose inner diameter is set to a diameter that can be fitted into the small diameter portion 5a of the piston rod 5, and is fitted to the outer circumference of the small diameter portion 5a of the piston rod 5.

[0028] The sub-piston 2 is annular in shape, with an outer diameter set to a diameter that allows it to slide against the inner circumference of the cylinder 1, and an inner diameter set to a diameter larger than the outer diameter of the collar 11, and is loosely fitted to the outer circumference of the collar 11.

[0029] Specifically, the sub-piston 2 comprises an annular body 2a, an annular outer valve seat 2c projecting axially from one end 2b of the body 2a which is the upper end in Figure 2, a plurality of ports 2d arranged on the same circumference on the inner circumference side of the outer valve seat 2c of the body 2a, an annular projection 2e projecting axially from the outer circumference side of the outer valve seat 2c at one end 2b of the body 2a, and a piston ring 2f mounted on the outer circumference of the body 2a and sliding against the inner circumference of the cylinder 1.

[0030] The axial height of one end 2b of the main body 2a increases from the inner circumference towards the outer circumference, and the axial length of the inner circumference side of the main body 2a is slightly shorter than the axial length of the collar 11.

[0031] As described above, each port 2d is arranged at equal intervals on the same circumference concentric with the main body 2a, and passes through the main body 2a to connect the intermediate chamber R3 and the extension chamber R1 between the sub-piston 2 and the piston 6.

[0032] The outer circumferential valve seat 2c protrudes axially from the main body 2a toward the upper side in Figure 2, surrounding the outer circumference of the port 2d, and is positioned above the inner circumferential valve seat 3c provided on the flange portion 3b of the valve stopper 3 in Figure 2. Furthermore, the inner diameter of the outer circumferential valve seat 2c is larger than the outer diameter of the inner circumferential valve seat 3c of the valve stopper 3.

[0033] The projection 2e is annular in shape and protrudes axially upward in Figure 2 from the outer circumference of the outer valve seat 2c, surrounding the outer valve seat 2c. Note that the projection 2e does not necessarily have to be annular, and multiple projections 2e may be installed on the same circumference surrounding the outer valve seat 2c.

[0034] When the sub-piston 2 is loosely fitted onto the collar 11, a gap is created between the inner circumference of the sub-piston 2 and the collar 11, allowing it to move radially relative to the collar 11. Also, since the axial length of the inner circumference of the sub-piston 2 is shorter than the axial length of the collar 11, it can be slightly displaced vertically in Figure 2 between the spacer 10 and the main valve stopper 12. Furthermore, when the sub-piston 2 is inserted into the cylinder 1, the outer circumference of the piston ring 2f slides against the inner circumference of the cylinder 1, and the sub-piston 2 is loosely fitted onto the collar 11, so the sub-piston 2 is positioned radially by the cylinder 1 alone. In addition, when the sub-piston 2 is loosely fitted onto the outer circumference of the collar 11, the inner valve seat 3c of the valve stopper 3 faces the inner circumference side of the body 2a of the sub-piston 2.

[0035] The leaf valve 4 is annular in shape, with an inner diameter smaller than the outer diameter of the inner valve seat 3c and larger than the outer diameter of the fitting portion 3a of the valve stopper 3. Its outer diameter is set so that it contacts a projection 2e located on the outer circumference side of the outer valve seat 2c. Since the outer circumference of the leaf valve 4 contacts the annular projection 2e of the sub-piston 2, the leaf valve 4 is aligned with the outer valve seat 2c of the sub-piston 2 by the projection 2e and positioned radially so as to be concentric with the outer valve seat 2c. In this way, the projection 2e functions as an alignment part that aligns the leaf valve 4 with respect to the outer valve seat 2c. Furthermore, the inner diameter of the leaf valve 4 is larger than the outer diameter of the fitting portion 3a to such an extent that even when aligned by the projection 2e, the inner surface of the leaf valve 4 does not come into contact with the fitting portion 3a of the opposing valve stopper 3. Thus, care is taken to ensure that the alignment of the leaf valve 4 by the projection 2e is not interfered with by the valve stopper 3.

[0036] As mentioned above, the projection 2e does not have to be annular in shape, and multiple projections may be provided spaced apart on the same circumference surrounding the outer valve seat 2c, as long as it is possible to align the leaf valve 4 concentrically with the outer valve seat 2c. Furthermore, the shape of the projection 2e can also be arbitrarily modified in design, as long as it is possible to align the leaf valve 4 concentrically with the outer valve seat 2c.

[0037] The leaf valve 4 is interposed between the inner valve seat 3c and the outer valve seat 2c, with the upper end of its inner circumference seated on the inner valve seat 3c in Figure 2 and the lower end of its outer circumference seated on the outer valve seat 2c in Figure 2. When pressure is received from the extension chamber R1 side, the inner circumference of the leaf valve 4 flexes downward in Figure 2, using the outer circumference supported by the outer valve seat 2c as a fulcrum, separating from the inner valve seat 3c of the valve stopper 3 and connecting port 2d to the compression chamber R2. On the other hand, when pressure is received from the intermediate chamber R3 side, the outer circumference of the leaf valve 4 flexes upward in Figure 2, using the inner circumference supported by the inner valve seat 3c as a fulcrum, separating from the outer valve seat 2c of the sub-piston 2 and connecting port 2d to the extension chamber R1.

[0038] Thus, the leaf valve 4 functions as a de carbon valve that opens both inward and outward. When the pressure in the extension chamber R1 becomes higher than the pressure in the intermediate chamber R3 and the pressure difference between the two reaches the opening pressure, it separates from the inner valve seat 3c and opens. When the pressure in the intermediate chamber R3 becomes higher than the pressure in the extension chamber R1 and the pressure difference between the two reaches the opening pressure, it separates from the outer valve seat 2c and opens. Furthermore, since the axial height of the body 2a of the sub-piston 2 decreases towards the inner circumference, sufficient space is secured between the inner valve seat 3c and the body 2a of the sub-piston 2, allowing the inner circumference of the leaf valve 4 to bend downward in Figure 2.

[0039] Furthermore, because the outer valve seat 2c of the sub-piston 2 is positioned higher than the inner valve seat 3c of the valve stopper 3 in Figure 2, when the leaf valve 4 is interposed between the inner valve seat 3c and the outer valve seat 2c, it is given an initial deflection and presses against the inner valve seat 3c and the outer valve seat 2c with the elastic force it generates. This initial deflection of the leaf valve 4 sets the valve opening pressure when the leaf valve 4 separates from the inner valve seat 3c and the outer valve seat 2c, and the valve opening pressure can be adjusted by adjusting the amount of initial deflection. The amount of initial deflection given to the leaf valve 4 can be adjusted by the difference in axial distance between the inner valve seat 3c and the outer valve seat 2c, so the valve opening pressure can be adjusted by adjusting the thickness of the annular plate of the spacer 10 and the number of layers.

[0040] The main valve stopper 12 is annular in shape, and its inner diameter is set to a diameter that can be fitted into the small diameter portion 5a of the piston rod 5, and is fitted into the small diameter portion 5a of the piston rod 5. The main valve stopper 12 has a relief portion 12a, which is an annular recess, on the outer circumference of the end of the main valve stopper 12 that faces the port 2d of the sub-piston 2, and even if the main valve stopper 12 faces the port 2d of the sub-piston 2, the relief portion 12a prevents the port 2d from being blocked.

[0041] Next, the compression side main leaf valve 7 has an inner diameter that can fit into the small diameter portion 5a of the piston rod 5. diameterThe valve is a laminated leaf valve composed of multiple annular plates stacked together, and is superimposed on the upper end of the piston 6 in Figure 2 to open and close the outlet end of the compression side main port 6a. An orifice 7a formed by a notch is provided on the outer circumference of the annular plate facing the piston 6 of the compression side main leaf valve 7. The inner circumference of the compression side main leaf valve 7 is sandwiched between the piston nut 13 and the stepped portion 5c, and only the deflection of the outer circumference is permitted.

[0042] When the compression-side main leaf valve 7 is in full contact with the piston 6, it connects the compression-side chamber R2 and the intermediate chamber R3 only through the orifice 7a. At the same time, the pressure in the compression-side chamber R2, received through the compression-side main port 6a, becomes higher than the pressure in the intermediate chamber R3. When the pressure difference between the two reaches the opening pressure, the valve 7 flexes and opens the compression-side main port 6a. The opening pressure of the compression-side main leaf valve 7 is set higher than the opening pressure of the leaf valve 4. The outer diameter of the annular plate constituting the compression-side main leaf valve 7 can be arbitrarily designed and changed according to the resistance that the compression-side main leaf valve 7 exerts on the flow of hydraulic fluid passing through the compression-side main port 6a.

[0043] The extension main leaf valve 8 has an inner diameter that can fit into the small diameter portion 5a of the piston rod 5. diameter The extension main leaf valve is constructed by stacking multiple annular plates set to a specific configuration, and is superimposed on the lower end of the piston 6 in Figure 2 to open and close the outlet end of the extension main port 6b. An orifice 8a, formed by a notch, is provided on the outer circumference of the annular plate facing the piston 6 of the extension main leaf valve 8. The extension main leaf valve 8 is held in place on its inner circumference by the piston nut 13 and the stepped portion 5c, and only the outer circumference is allowed to bend.

[0044] And the extension main leaf valve 8 is , Pi When the entire structure is in contact with stone 6, the intermediate chamber R3 and the compression chamber R2 are connected only by the orifice 8a, while the extension main port 6b is also connected. receiveWhen the pressure in the intermediate chamber R3 becomes higher than the pressure in the compression chamber R2, and the pressure difference between the two reaches the valve opening pressure, the valve flexes and opens the extension main port 6b. The opening pressure of the extension main leaf valve 8 is set higher than the opening pressure of the leaf valve 4. The outer diameter of the annular plate constituting the extension main leaf valve 8 can be arbitrarily designed and changed according to the setting of the resistance that the extension main leaf valve 8 exerts on the flow of hydraulic fluid passing through the extension main port 6b.

[0045] As described above, the damping valve V1 is configured to include a sub-piston 2 as a partition body, which is an annular shape inserted into a cylinder 1 as a cylindrical body and positioned radially by the cylinder 1 alone, and has an annular outer valve seat 2c that protrudes axially from one end 2b in the axial direction and a port 2d provided on the inner circumference side of the outer valve seat 2c; a valve stopper 3 that faces one end 2b of the sub-piston 2 and has an annular inner valve seat 3c with a smaller outer diameter than the outer valve seat 2c; and an annular leaf valve 4 interposed between the outer valve seat 2c and the inner valve seat 3c and set to open both inward and outward to open and close the port 2d. Furthermore, the sub-piston 2 in the damping valve V1 is provided with a projection 2e as an aligning part that aligns the leaf valve 4 with respect to the outer valve seat 2c.

[0046] The operation of the damping valve V1 and shock absorber D will be described below. First, the operation when the piston rod 5 moves upward relative to the cylinder 1 in Figure 1 and the shock absorber D extends will be described. When the shock absorber D extends, the piston 6 and sub-piston 2 move upward relative to the cylinder 1 in Figure 1, so the extension chamber R1 is compressed and the compression chamber R2 is expanded.

[0047] As a result, the pressure in the extension chamber R1 increases, and when the difference between the pressure in the extension chamber R1 and the pressure in the intermediate chamber R3 reaches the opening pressure of the leaf valve 4, the leaf valve 4 bends its inner circumference downward in Figure 2, separating from the inner valve seat 3c and opening the port 2d of the sub-piston 2.

[0048] When the extension speed of buffer D is very slow and the extension-side main leaf valve 8 is not open, the hydraulic fluid in the extension-side chamber R1 flexes the inner circumference of the leaf valve 4, passes through port 2d, goes through the intermediate chamber R3, and moves to the compression-side chamber R2 through the compression-side and extension-side main ports 6a, 6b and orifices 7a, 8a.

[0049] Thus, when the shock absorber D is in extension mode and its extension speed is in the very low speed range, the flow rate of hydraulic fluid passing through orifices 7a and 8a is very small. Therefore, the pressure loss that occurs when the hydraulic fluid passes through leaf valve 4 is greater than the pressure loss that occurs when the hydraulic fluid passes through orifices 7a and 8a. Consequently, when the shock absorber D extends in the very low speed range, the damping force is mainly exerted by leaf valve 4.

[0050] Furthermore, when the extension speed of the buffer D is in the low-speed range, the extension-side main leaf valve 8 does not open, but the pressure loss in the orifices 7a and 8a increases, so the buffer D exerts damping force through the leaf valve 4 and the orifices 7a and 8a.

[0051] Furthermore, when the extension speed of the shock absorber D increases during this extension operation, the extension-side main leaf valve 8 bends and opens, causing the extension-side main port 6b to open widely, and the shock absorber D exerts damping force mainly through the leaf valve 4 and the extension-side main leaf valve 8.

[0052] Next, we will explain the operation when the piston rod 5 moves downward relative to the cylinder 1 in Figure 1, causing the shock absorber D to contract. When the shock absorber D contracts, the piston 6 and sub-piston 2 move downward relative to the cylinder 1 in Figure 1, so the compression chamber R2 is compressed and the extension chamber R1 is expanded.

[0053] As a result, the pressure in the compression chamber R2 increases, and the hydraulic fluid in the compression chamber R2 moves to the intermediate chamber R3 via the compression and extension main ports 6a, 6b and orifices 7a, 8a when the compression main leaf valve 7 is closed, and mainly via the compression main port 6a when the compression main leaf valve 7 is open. When the difference between the pressure in the intermediate chamber R3 and the pressure in the extension chamber R1 reaches the opening pressure of the leaf valve 4, the leaf valve 4 bends its outer circumference upward in Figure 2, separating from the outer valve seat 2c and opening the port 2d of the sub-piston 2.

[0054] When the extension speed of buffer D is very slow and the compression-side main leaf valve 7 is not open, the hydraulic fluid in the compression-side chamber R2 passes through the compression-side and extension-side main ports 6a, 6b and orifices 7a, 8a, then through the intermediate chamber R3, causing the outer circumference of the leaf valve 4 to flex, pass through port 2d, and move to the extension-side chamber R1.

[0055] Thus, when the shock absorber D is contracting and its contraction speed is in the very low speed range, the flow rate of hydraulic fluid passing through orifices 7a and 8a is very small. Therefore, the pressure loss when the hydraulic fluid passes through the leaf valve 4 is greater than the pressure loss when the hydraulic fluid passes through orifices 7a and 8a. Consequently, when the shock absorber D contracts in the very low speed range, the damping force is mainly exerted by the leaf valve 4. Furthermore, the inner circumferential surface of the projection 2e is a tapered surface that slopes so that the tip, which is the upper end in the axial direction, tapers to a point. When the outer circumference of the leaf valve 4 bends and separates from the outer valve seat 2c, the flow area formed by the annular gap between the outer valve seat 2c and the leaf valve 4 is not limited by the presence of the projection 2e, so the damping force of the leaf valve 4 after opening becomes excessive. but No. However, if there is a risk that the flow area after the leaf valve 4 opens will be limited by the projection 2e, instead of making the projection 2e annular, multiple projections 2e can be provided at intervals on the outer circumference of the outer valve seat 2c so that the flow area is not limited by the projection 2e.

[0056] Furthermore, when the contraction speed of the buffer D is in the low-speed range, the compression-side main leaf valve 7 does not open, but the pressure loss at the orifices 7a and 8a increases, so the buffer D exerts damping force through the leaf valve 4 and the orifices 7a and 8a.

[0057] Furthermore, when the extension speed of the shock absorber D becomes high during this extension operation, the compression-side main leaf valve 7 bends and opens, causing the compression-side main port 6a to open widely, and the shock absorber D exerts damping force mainly through the leaf valve 4 and the compression-side main leaf valve 7.

[0058] In this embodiment of the shock absorber D, the speed range in which damping force is mainly generated by the leaf valve 4 is set to very low speed, the speed range in which damping force is mainly generated by the orifices 7a and 8a is set to low speed, and the speed range in which damping force is mainly generated by the compression-side main leaf valve 7 or the extension-side main leaf valve 8 is set to high speed. The speeds for which the classifications of very low speed, low speed, and high speed are made can be arbitrarily set by the designer. In addition, either orifice 7a or 8a can be omitted, and furthermore, orifices 7a and 8a may be provided on the piston 6 instead of on the compression-side main leaf valve 7 and the extension-side main leaf valve 8.

[0059] Here, the leaf valve 4 is centered so as to be concentric with the outer peripheral valve seat 2c of the sub-piston 2, which is radially positioned by the cylinder 1, by a projection 2e that functions as a centering part of the sub-piston 2. Because the leaf valve 4 is centered so as to be concentric with the outer peripheral valve seat 2c in this way, it is possible to prevent a gap from forming between the outer circumference of the leaf valve 4 and the outer peripheral valve seat 2c, which are given initial deflection due to the difference in height between the outer peripheral valve seat 2c and the inner peripheral valve seat 3c. On the other hand, the valve stopper 3, which has an inner peripheral valve seat 3c, is fitted onto the piston rod 5 and is radially positioned with respect to the piston rod 5. Therefore, there may be cases where the leaf valve 4, which is radially positioned with respect to the cylinder 1 via the sub-piston 2, and the inner peripheral valve seat 3c, which is radially positioned with respect to the piston rod 5, are eccentric. In this way, the inventors' research has shown that even if the annular leaf valve 4 is eccentric with respect to the inner peripheral valve seat 3c, a gap large enough to significantly affect the damping force does not form between the inner circumference of the leaf valve 4 and the inner peripheral valve seat 3c.

[0060] Therefore, when the leaf valve 4 is seated on the outer valve seat 2c and the inner valve seat 3c, no gap is formed between the outer circumference of the leaf valve 4 and the outer valve seat 2c, and even if the annular leaf valve 4 is eccentric with respect to the inner valve seat 3c, no gap large enough to significantly affect the damping force is created between the inner circumference of the leaf valve 4 and the inner valve seat 3c. From the above, the damping force characteristics when the shock absorber D equipped with the damping valve V1 expands and contracts at a very low speed are as shown in Figure 3, and a damping force of sufficient height to suppress the expansion and contraction of the shock absorber D from the start of its movement is exhibited. In contrast, when a conventional shock absorber equipped with a damping valve that creates a gap between the leaf valve and the outer valve seat when the leaf valve is seated on the outer valve seat expands and contracts at a very low speed, the damping force characteristics when the shock absorber expands and contracts at a very low speed are as shown by the dashed line in Figure 3, and the damping force is insufficient to suppress the expansion and contraction of the shock absorber. In contrast, the shock absorber D of this embodiment can exhibit a high damping force that can suppress such expansion and contraction when it expands and contracts at a very low speed.

[0061] Based on the above, the shock absorber D can exert sufficient damping force even when expanding and contracting at very low speeds, and good damping force characteristics are obtained to suppress such expansion and contraction when the shock absorber D expands and contracts at very low speeds.

[0062] When the buffer D repeatedly expands and contracts at a very low speed, the compression-side main leaf valve 7 and the extension-side main leaf valve 8 do not open, and the leaf valve 4 opens and closes port 2d. In this way, when the buffer D repeatedly expands and contracts at a very low speed and switches from extension to contraction, during extension, the sub-piston 2 separates from the spacer 10 due to the pressure in the extension-side chamber R1, and the inner circumference of the leaf valve 4 bends and separates from the inner valve seat 3c. When the direction of expansion and contraction of the buffer D changes from this state to contraction, the leaf valve 4 returns to a position where it contacts the inner valve seat 3c due to the action of the compression-side chamber R2 and its own restoring force. However, since the sub-piston 2 is separated from the spacer 10, the impact of the leaf valve 4 colliding with the inner valve seat 3c is not transmitted to the piston rod 5. When the shock absorber D repeatedly expands and contracts at a very low speed, and switches from contraction to extension, during contraction, the sub-piston 2 separates from the main valve stopper 12 due to the pressure in the intermediate chamber R3, and the outer circumference of the leaf valve 4 bends and separates from the outer valve seat 2c. When the direction of expansion and contraction of the shock absorber D changes from this state to extension, the leaf valve 4 returns to a position where it contacts the outer valve seat 2c due to the action of the extension chamber R1 and its own restoring force. However, since the sub-piston 2 is separated from the main valve stopper 12, the impact of the leaf valve 4 colliding with the outer valve seat 2c is not transmitted to the piston rod 5.

[0063] Thus, in the shock absorber D of this embodiment, the shock generated when the leaf valve 4, which is separated from one of the outer valve seat 2c and the inner valve seat 3c, sits on one of the outer valve seat 2c and the inner valve seat 3c is not transmitted to the piston rod 5, and therefore vibrations are not transmitted to the vehicle body.

[0064] Furthermore, in the buffer D of this embodiment, the leaf valve 4 has an outer valve seat 2c and an inner valve seat 3cWith the sub-piston 2 seated, it is biased axially, and even if the sub-piston 2 moves in the opposite direction to the biasing direction of the leaf valve 4, it can be returned to its original position (the position where the sub-piston 2 contacts the main valve stopper 12). Furthermore, the problem of the port 2d remaining open due to being unable to shut off regardless of the position of the sub-piston 2 does not occur. Therefore, with the shock absorber D configured in this way, the damping force can be exerted as set even when expanding and contracting at very low speeds, eliminating the risk of insufficient damping force and deterioration of ride comfort.

[0065] As described above, the damping valve V1 of this embodiment comprises a sub-piston (partition body) 2 which is annular and inserted into a cylinder (tubular body) 1 and positioned radially by the cylinder (tubular body) 1 alone, and has an annular outer valve seat 2c that protrudes axially from one end 2b in the axial direction and a port 2d provided on the inner circumference side of the outer valve seat 2c; a valve stopper 3 which faces one end 2b of the sub-piston (partition body) 2 and has an annular inner valve seat 3c that has a smaller outer diameter than the outer valve seat 2c; and an annular leaf valve 4 which is interposed between the outer valve seat 2c and the inner valve seat 3c and is set to open both inward and outward to open and close the port 2d, and the sub-piston (partition body) 2 is provided with a projection (aligning part) 2e that aligns the leaf valve 4 with respect to the outer valve seat 2c.

[0066] In the damping valve V1 configured in this way, the leaf valve 4 is centered relative to the outer valve seat 2c by a projection (centering part) 2e provided on the sub-piston (partition) 2, which is radially positioned by the cylinder (tube) 1 alone. As a result, when the leaf valve 4 is seated on the outer valve seat 2c and the inner valve seat 3c, no gap is created between the outer circumference of the leaf valve 4 and the outer valve seat 2c, and no gap is created between the inner circumference of the leaf valve 4 and the inner valve seat 3c that would affect the damping force. According to the damping valve V1 of this embodiment, leakage of hydraulic fluid from the gap can be prevented, and a sufficiently large damping force can be generated in the buffer D even when the flow rate of hydraulic fluid passing through the port 2d is small. Therefore, according to the damping valve V1 of this embodiment, a good damping force characteristic can be obtained that exhibits sufficient damping force even when the buffer D expands and contracts at very low speeds, thereby suppressing such expansion and contraction.

[0067] Furthermore, in the damping valve V1 of this embodiment, the self-aligning portion provided on the sub-piston (partition) 2 is a projection 2e that protrudes axially from the outer circumference of the outer peripheral valve seat 2c at one end 2b of the sub-piston (partition) 2 and abuts against the outer circumference of the leaf valve 4. By making the projection 2e provided in close proximity to the outer peripheral valve seat 2c the self-aligning portion in this way, the self-alignment accuracy of the leaf valve 4 with respect to the outer peripheral valve seat 2c is improved.

[0068] Furthermore, the damping valve V1 of this embodiment is configured to include a piston (main partition) 6 inserted into the cylinder (tube) 1 facing the sub-piston (partition) 2 in the axial direction and equipped with a compression-side main port (main port) 6a and an extension-side main port (main port) 6b, and a main valve comprising a compression-side main leaf valve 7 that opens and closes the compression-side main port (main port) 6a and is set to an opening pressure higher than that of the leaf valve 4, and an extension-side main leaf valve 8 that opens and closes the extension-side main port (main port) 6b ​​and is set to an opening pressure higher than that of the leaf valve 4. With the damping valve V1 configured in this way, the leaf valve 4 can exert a damping force suitable for when the shock absorber D expands and contracts at a very low speed, and the main valve can exert a large damping force when the expansion and contraction speed of the shock absorber D becomes high speed. Therefore, with the damping valve V1 of this embodiment, a damping force suitable for suppressing the expansion and contraction of the shock absorber D can be generated in the shock absorber D according to the expansion and contraction speed of the shock absorber D. Furthermore, in the damping valve V1 of this embodiment, where the piston (main bulkhead) 6 is fixed to the piston rod 5 and inserted into the cylinder (tube) 1, the sub-piston 2 can move radially relative to the piston rod 5. Therefore, even if there are dimensional errors in the piston 6, piston rod 5, or sub-piston 2, the sliding resistance between the sub-piston 2 and the cylinder 1 does not become large. Thus, with the buffer D configured in this way, even if a structure is adopted in which the piston (main bulkhead) 6 and the sub-piston 2 slide against the cylinder 1, the sliding resistance does not become large, allowing for smooth expansion and contraction, and eliminating the need for advanced dimensional control, thus reducing costs. Note that if the main port allows bidirectional flow rather than unidirectional flow, the main valve may be composed of a single valve. In this case, for example, the main valve may be a decarbon valve.

[0069] Furthermore, the shock absorber D of this embodiment comprises a cylinder 1, a piston rod 5 inserted into the cylinder 1, and a damping valve V1, with the cylinder 1 being a cylindrical body. With the shock absorber D configured in this way, because it is equipped with a damping valve V1, sufficient damping force can be exerted even when expanding and contracting at very low speeds, and good damping force characteristics can be obtained for suppressing expansion and contraction.

[0070] In the damping valve V1 of the embodiment described above, a projection 2e is provided on the outer circumference side of the outer valve seat 2c of the sub-piston 2 that abuts against the outer circumference of the leaf valve 4, and this projection 2e is used as the centering part. However, as shown in the damping valve V2 of one modified embodiment in Figure 4, a projection 21e may be provided that protrudes axially from the inner circumference side of the port 21d of the sub-piston 21 and abuts against the inner circumference of the leaf valve 4, and this projection 21e may be used as the centering part. In describing the damping valve V2 of one modified embodiment, in order to avoid duplication of explanation, the same reference numerals are used for parts that are the same as those of the damping valve V1 of one embodiment, and detailed explanations are omitted.

[0071] In one modified example, the sub-piston 21, acting as a partition in the damping valve V2, is identical to the sub-piston 2 in the damping valve V1 of one embodiment in that it comprises an annular body 21a, an annular outer valve seat 21c projecting axially from one end 21b which is the upper end in Figure 3 in the axial direction of the body 21a, a plurality of ports 21d arranged on the same circumference on the inner circumference side of the outer valve seat 21c of the body 21a, and a piston ring 21f mounted on the outer circumference of the body 21a and sliding against the inner circumference of the cylinder 1. However, it differs in configuration from the sub-piston 2 in that it does not have a projection on the outer circumference side of the outer valve seat 21c, but instead has a plurality of projections 21e arranged at equal intervals on the same circumference on the inner circumference of the body 21a, closer to the port 21d at one end 21b.

[0072] Ignoring the projection 21e, the axial height of one end 21b of the main body 21a increases from the inner circumference towards the outer circumference, and the axial length of the inner circumference side of the main body 21a is slightly shorter than the axial length of the collar 11.

[0073] As described above, each port 21d is arranged at equal intervals on the same circumference concentric with the main body 21a, and passes through the main body 21a to connect the intermediate chamber R3 and the extension chamber R1 between the sub-piston 2 and the piston 6.

[0074] The outer periphery valve seat 21c extends axially from the main body 21a so as to surround the outer circumference of the port 21d. 4It protrudes toward the upper and middle side. Furthermore, when viewing the sub-piston 21 from above in Figure 4, the projection 21e has an arc-shaped cross-section, and its outer surface is curved, so that the outer surfaces of each projection 21e are tangent to the same circle with the same curvature.

[0075] Furthermore, the protrusions 21e are spaced apart in the circumferential direction and are not arranged to overlap with the port 21d in the radial direction, so as to ensure that the flow area of ​​the port 21d is not reduced by providing the protrusions 21e. In other words, a portion of the port 21d is formed between the protrusions 21e, 21e in the circumferential direction of the sub-piston 21, but in particular, if there is no problem in securing the flow area of ​​the port 21d, it is not necessary to provide a portion of the port 21d between the protrusions 21e, 21e.

[0076] When the sub-piston 21 is loosely fitted into the collar 11, a gap is created between the inner circumference of the sub-piston 21 and the collar 11, allowing it to be slightly displaced in the vertical direction in Figure 4, which is axial. Furthermore, when the sub-piston 21 is inserted into the cylinder 1, the outer circumference of the piston ring 21f slides against the inner circumference of the cylinder 1, and the sub-piston 21 is loosely fitted into the collar 11, so the sub-piston 21 is positioned radially by the cylinder 1 alone.

[0077] In one modified example, the valve stopper 31, as shown in Figure 4, comprises an annular fitting portion 31a whose inner diameter is reduced at the lower end in Figure 4, a flange portion 31b that protrudes outward from the end of the fitting portion 31a that protrudes upward in Figure 4 from the projection 21e of the sub-piston 21 and faces the upper end of the projection 21e in Figure 4 with a gap between them, and an annular inner valve seat 31c that extends from the outer circumference of the flange portion 31b toward the sub-piston 21 and is positioned on the outer circumference of the projection 21e and faces the sub-piston 21. 4 The inner diameter of the middle lower end is set to a diameter that can fit onto the outer circumference of the small diameter portion 5a of the piston rod 5, and the inner diameter of the fitting portion 31a on the upper end side in Figure 4 is larger than the small diameter portion 5a of the piston rod 5. 4The diameter is larger than the outer diameter of the middle and upper side. Therefore, when the valve stopper 31 is fitted onto the small diameter portion 5a of the piston rod 5, the inner circumference of the lower end of the fitting portion 31a fits onto the small diameter portion 5a of the piston rod 5, positioning the valve stopper 31 radially relative to the piston rod 5, and the stepped portion at the boundary between the lower and upper ends of the fitting portion 31a abuts against the stepped portion 5c of the piston rod 5, positioning the valve stopper 31 axially relative to the piston rod 5.

[0078] Furthermore, after assembling the valve stopper 31 together with the spacer 10 and collar 11 onto the piston rod 5, when the sub-piston 21 is loosely fitted onto the outer circumference of the collar 11, the projection 21e of the sub-piston 21 is accommodated in the annular gap formed between the fitting portion 31a and the inner valve seat 31c, and the inner valve seat 31c faces the inner circumference side of the body 21a of the sub-piston 21. The outer diameter of the inner valve seat 31c in the valve stopper 31 is smaller than the inner diameter of the outer valve seat 21c, and the outer valve seat 21c is positioned higher than the inner valve seat 31c in Figure 4.

[0079] The leaf valve 4 has an inner diameter smaller than the outer diameter of the inner circumferential valve seat 31c and is set to a diameter that contacts the outer circumferential surface of each projection 21e of the sub-piston 21, and the outer diameter is smaller than the outer circumferential valve seat 21c The diameter is set to be larger than the inner diameter of the subpiston 21. Therefore, when the leaf valve 4 is placed on the subpiston 21, the inner circumference of the leaf valve 4 comes into contact with each projection 21e of the subpiston 21, so that the leaf valve 4 is aligned with the outer valve seat 21c of the subpiston 2 by the projections 21e and positioned radially so that it is concentric with the outer valve seat 21c. In this way, the projections 21e function as alignment parts that align the leaf valve 4 with respect to the outer valve seat 21c.

[0080] In addition, the leaf valve 4 does not have to be arc-shaped as long as it is centered concentrically with respect to the outer valve seat 21c. However, if it is arc-shaped, the inner circumference of the leaf valve 4 can slide more easily on the outer surface of the projection 21e, thereby ensuring smooth deflection of the inner circumference of the leaf valve 4.

[0081] Then, the leaf valve 4 seats the upper end of its inner circumference (in Figure 4) on the inner valve seat 31c, and the lower end of its outer circumference (in Figure 4) on the outer valve seat 21c In a seated position, it is interposed between the inner valve seat 31c and the outer valve seat 21c. Therefore, in one modified example, the leaf valve 4 in the damping valve V2 functions as a de carbon valve that opens both inward and outward, similar to the damping valve V1. Furthermore, since the axial height of the body 21a of the sub-piston 21 decreases towards the inner circumference, sufficient space is secured between the inner valve seat 31c and the body 21a of the sub-piston 21, allowing the inner circumference of the leaf valve 4 to bend downward in Figure 4. In addition, since the projections 21e are provided at intervals in the circumferential direction, when the inner circumference of the leaf valve 4 separates from the inner valve seat 31c, the extension chamber R1 and the port 21d are connected through the gap between the projections 21e, 21e.

[0082] Furthermore, because the outer circumferential valve seat 21c of the sub-piston 21 is positioned higher than the inner circumferential valve seat 31c of the valve stopper 31 in Figure 4, when the leaf valve 4 is interposed between the inner circumferential valve seat 31c and the outer circumferential valve seat 21c, an initial deflection is given according to the height difference between the inner circumferential valve seat 31c and the outer circumferential valve seat 21c. By giving the leaf valve 4 this initial deflection, the valve opening pressure when the leaf valve 4 separates from the inner circumferential valve seat 31c and the outer circumferential valve seat 21c is set, and the valve opening pressure can be adjusted by adjusting the amount of initial deflection. Note that the amount of initial deflection given to the leaf valve 4 can be adjusted by the difference in axial distance between the inner circumferential valve seat 31c and the outer circumferential valve seat 21c, so the valve opening pressure can be adjusted by adjusting the plate thickness and number of stacked plates of the annular plate of the spacer 10.

[0083] In one modified example, the damping valve V2 is provided with a main valve stopper 12, a compression-side main leaf valve 7, a piston 6, and an extension-side main leaf valve 8 below the sub-piston 21 in Figure 4, similar to the damping valve V1. Therefore, the damping valve V2 generates damping force on the shock absorber D by the leaf valve 4 when the shock absorber D expands and contracts at a very low speed, by the orifices 7a and 8a when the shock absorber D expands and contracts at a low speed, and by the compression-side main leaf valve 7 or the extension-side main leaf valve 8 when the shock absorber D expands and contracts at a high speed.

[0084] Furthermore, in the damping valve V2 in one modified example, the leaf valve 4 is aligned so as to be concentric with the outer peripheral valve seat 21c of the sub-piston 21, which is radially positioned by the cylinder 1, by the projection 21e which functions as the centering part of the sub-piston 21. In this way, the leaf valve 4 is aligned so as to be concentric with the outer peripheral valve seat 21c, so the leaf valve 4 is concentric with the outer peripheral valve seat 21c and inner valve seat 31c In the seated position, the outer circumference of the leaf valve 4 and the outer valve seat 21c No gap is formed between them, and the annular leaf valve 4 is the inner circumferential valve seat 31c Even if eccentric, the inner circumference of the leaf valve 4 and the inner valve seat 31c There is no gap between them that would significantly affect the damping force. Therefore, when the shock absorber D equipped with the damping valve V2 expands and contracts at a very low speed, the damping force characteristics, as shown in Figure 3, are such that a damping force of sufficient height is exerted from the start of the movement of the shock absorber D to suppress the expansion and contraction of the shock absorber D. Therefore, the shock absorber D can exert sufficient damping force even when expanding and contracting at a very low speed, and good damping force characteristics are obtained to suppress the expansion and contraction when the shock absorber D expands and contracts at a very low speed.

[0085] As described above, the damping valve V2 in one modified example of this embodiment comprises a sub-piston (partition) 21 which is annular and inserted into a cylinder (tube) 1 and positioned radially by the cylinder (tube) 1 alone, and has an annular outer valve seat 21c that protrudes axially from one end 21b in the axial direction and a port 21d provided on the inner circumference side of the outer valve seat 21c; a valve stopper 31 which faces one end 21b of the sub-piston (partition) 21 and has an annular inner valve seat 31c that has a smaller outer diameter than the outer valve seat 21c; and an annular leaf valve 4 which is interposed between the outer valve seat 21c and the inner valve seat 31c and is set to open both inward and outward to open and close the port 21d, and the sub-piston (partition) 21 is provided with a projection (aligning part) 21e that aligns the leaf valve 4 with respect to the outer valve seat 21c.

[0086] In the damping valve V2 configured in this way, the leaf valve 4 is aligned with respect to the outer valve seat 21c by a projection (aligning part) 21e provided on the sub-piston 21 which is positioned only on the cylinder (tube) 1. Therefore, when the leaf valve 4 is seated on the outer valve seat 21c and the inner valve seat 31c, the outer circumference of the leaf valve 4 and the outer valve seat 21c No gap is created between the leaf valve 4 and the inner circumference of the leaf valve 4, and no gap is created between the inner circumference of the leaf valve 4 and the inner circumference valve seat 31c that would affect the damping force. According to the damping valve V2 of this embodiment, leakage of hydraulic fluid from the gap can be prevented, and a sufficiently large damping force can be generated in the buffer D even when the flow rate of hydraulic fluid passing through port 21d is small. Therefore, according to the damping valve V2 of this embodiment, a good damping force characteristic can be obtained that exhibits sufficient damping force even when the buffer D expands and contracts at very low speeds, thereby suppressing such expansion and contraction.

[0087] Furthermore, in the damping valve V2 of this embodiment, the self-aligning portion provided on the sub-piston (partition) 2 is a plurality of protrusions 21e that project axially from the inner circumference side of the port 21d at one end 21b of the sub-piston (partition) 2, spaced apart in the circumferential direction, and contact the inner circumference of the leaf valve 4. By using the protrusions 21e provided on the inner circumference side of the port 21d as the self-aligning portion in this way, the outer diameter of the leaf valve 4 can be made smaller than the outer diameter of the outer valve seat 21c, thereby improving the design freedom of the leaf valve 4.

[0088] In this embodiment, damping valves V1 and V2 are mounted on the piston rod 5 and installed on the piston portion of the shock absorber D. However, if the shock absorber D is a shock absorber that has a reservoir chamber for storing liquid on the outer circumference of the cylinder 1, a partition body or a partition body and a main partition body may be provided at the end of the cylinder 1 to separate the pressure side chamber R2 from the reservoir, and damping valves V1 and V2 may be installed between the pressure side chamber R2 and the reservoir chamber. In other words, damping valves V1 and V2 may be installed on the base valve portion of the shock absorber D. Furthermore, since damping valves V1 and V2 only need to be installed in a location where damping force can be generated when the shock absorber D expands and contracts, the installation location of damping valves V1 and V2 will change depending on the configuration of the shock absorber D, but damping valves V1 and V2 should be installed in the optimal location according to the configuration of the shock absorber D. Furthermore, since damping valves V1 and V2 can generate damping force using only leaf valves 4, without the need for a main bulkhead body equipped with a main port and a main valve to open and close the main port, it is natural that damping valves V1 and V2, which consist of a bulkhead body 2 (21), a valve stopper 3 (31), and leaf valves 4, can be used as buffers D without a main bulkhead body or main valve.

[0089] Although preferred embodiments of the present invention have been described in detail above, modifications, alterations, and changes are permitted as long as they do not deviate from the scope of the claims. [Explanation of Symbols]

[0090] 1...Cylinder (tube), 2, 21...Sub-piston (partition), 2b, 21b...One end of sub-piston, 2c, 21c...Outer valve seat, 2d, 21d...Port, 2e, 21e...Projection (aligning part), 3, 31...Valve stopper, 3c, 31c...Inner valve seat, 4...Leaf valve, 5...Piston rod, 6...Piston (main part), 6a...Compression side main port (main port), 6b...Rebound side main port (main port), 7...Compression side main leaf valve (main valve), 8...Rebound side main leaf valve (main valve), D...Buffer, V1, V2...Damping valve

Claims

1. A partition wall having an annular outer valve seat that is inserted into a cylindrical body and positioned radially by the cylindrical body alone, and which protrudes axially from one end in the axial direction, and a port provided on the inner circumference side of the outer valve seat, A rod inserted into the inner circumference of the partition wall, A valve stopper having an annular inner valve seat that faces one end of the partition wall and has a smaller outer diameter than the outer valve seat, The system includes an annular leaf valve interposed between the outer circumferential valve seat and the inner circumferential valve seat, which is set to open both inward and outward to open and close the port, The partition wall has an alignment portion that aligns the leaf valve with respect to the outer valve seat, and is movable radially relative to the rod. A damping valve characterized by the following features.

2. The self-aligning portion is a projection that protrudes axially from the outer circumference of the outer peripheral valve seat at one end of the partition body and contacts the outer circumference of the leaf valve. The damping valve according to feature 1.

3. The self-aligning portion is a projection that protrudes axially from the inner circumference of the partition wall body beyond the port and contacts the inner circumference of the leaf valve. The damping valve according to feature 1.

4. A main partition body is inserted into the cylindrical body, facing the aforementioned partition body in the axial direction, and has a main port. The system includes a main valve that opens and closes the main port and is set to an opening pressure higher than the opening pressure of the leaf valve. A damping valve according to any one of claims 1 to 3.

5. Cylinder and A piston rod inserted into the cylinder, A damping valve according to any one of claims 1 to 4, The cylinder is the cylindrical body. A buffer characterized by the following features.

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