Valve and shock absorber

Abstract

This valve (1) is provided with: an annular valve seat member (2) that has a seat section (2b) on the inner periphery thereof; a guide member (3) that has an alignment shaft (3a) that passes through the valve seat member (2) and that is aligned with the valve seat member (2); a valve body (4) that is in sliding contact with the outer periphery of the alignment shaft (3a), can move in the axial direction with respect to the valve seat member (2), and is removably seated on the seat section (2b); an annular disk spring (5) that is interposed between the outer periphery of the valve seat member (2) and the valve body (4) and biases the valve body (4) in a direction away from the seat section (2b); and an actuator (S) that can impart thrust to the valve body (4) in the direction in which the valve body (4) is seated in the seat section (2b).

Description

Valve and shock absorber

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

[0002] In a shock absorber that exhibits a damping force for suppressing vibration, for example, a cylinder, a rod that is axially movably inserted into the cylinder, a piston that is connected to the rod and inserted into the cylinder to partition the inside of the cylinder into an extension chamber and a compression chamber, an outer tube that covers the cylinder and forms a reservoir between the cylinder, and a main valve body provided in the middle of a damping passage that communicates the extension chamber and the reservoir and is housed in a cylindrical housing provided on the side of the outer tube, and a valve capable of adjusting the opening pressure of the main valve body. In this shock absorber, the resistance applied to the flow of the working oil generated when the shock absorber expands and contracts by the valve can be adjusted to adjust the damping force generated by the shock absorber.

[0003] As shown in FIG. 5, a valve used in such a shock absorber includes a valve seat member 200, a valve body 207 that seats and separates from the valve seat member 200, a spring 215 that biases the valve body 207 in a direction separating from the valve seat member 200, and a solenoid 220 that can exert a force to press the valve body 207 toward the valve seat member 200, and is provided in a pilot passage 232 that adjusts the pressure in a back pressure chamber 231 that biases the main valve body 230. And, for example, the valve disclosed in JP2017-57864A adjusts the pressure in the back pressure chamber 231 according to the amount of current supplied to the solenoid 220, adjusts the opening pressure of the main valve body 230, and controls the damping force generated by the shock absorber.

[0004] JP2017-57864A

[0005] More specifically, the valve seat member 200 in the conventional valve described above is configured as shown in Figure 5, and comprises a bottomed cylindrical small-diameter portion 201, a flange portion 202 protruding outward from the outer circumference of the open end of the small-diameter portion 201, a large-diameter portion 203 extending from the outer circumference of the flange portion 202 toward the opposite side from the small-diameter portion 201, an inlet port 204 opening diagonally from the side of the small-diameter portion 201 toward the inner circumference of the flange portion 202, an outlet port 205 passing radially through the large-diameter portion 203 and communicating the inside and outside of the large-diameter portion 203, and an annular valve seat 206 formed on the inner circumference of the flange portion 202.

[0006] On the other hand, the valve body 207 in a conventional valve is configured to include a small-diameter portion 208 that is slidably inserted into a small-diameter cylindrical portion 201, a large-diameter portion 209 connected to the base end of the small-diameter portion 208, an annular recess 210 provided between the small-diameter portion 208 and the large-diameter portion 209, a flange-shaped spring receiving portion 211 provided on the outer circumference of the end of the large-diameter portion 209 opposite the small-diameter portion, a communication passage 212 that penetrates from the tip of the small-diameter portion 208 to the rear end of the large-diameter portion 209, and an orifice 213 provided in the middle of the communication passage 212.

[0007] In this configuration, the valve body 207 has a small-diameter portion 208 that is slidably inserted into the small-diameter cylindrical portion 201 of the valve seat member 200, and can move axially relative to the valve seat member 200. By seating the outer circumference of the large-diameter portion 209 on and off the annular valve seat 206, the pilot passage 232 can be opened and closed.

[0008] The spring 215 is a disc spring comprising an annular ring 215a that rests on a stepped portion provided on the inner circumference of the large-diameter cylindrical portion 203 of the valve seat member 200, and a plurality of arms 215b that extend inward from the inner circumference of the annular ring 215a, with the tips of the arms 215b in contact with the ends of the spring receiving portion 211 of the valve body 207. In this way, the spring 215 is interposed between the large-diameter cylindrical portion 203 of the valve seat member 200 and the spring receiving portion 211 of the valve body 207, biasing the valve body 207 so as not to seat on the annular valve seat 206 of the valve seat member 200.

[0009] As described above, the valve seat member 200 has a complex structure because it performs numerous functions, including aligning the valve body 207, guiding the axial movement of the valve body 207, a valve seat with an annular valve seat 206, a component that forms inlet and outlet flow paths with an inlet port 204 and an outlet port 205, and a spring support that supports the spring 215.

[0010] Furthermore, the valve body 207 has a large diameter portion 209 and a spring receiving portion 211 at the rear end of a small diameter portion 208 that is slidably inserted into the small diameter cylindrical portion 201 of the valve seat member 200. In addition to opening and closing the pilot passage 232 by the seating of the large diameter portion 209 with respect to the annular valve seat 206, it also has a recess 210 in the middle so that the inlet port 204 can be opened and closed depending on its axial position relative to the valve seat member 200, thus having a complex structure similar to the valve seat member 200.

[0011] Therefore, in conventional valves, the structure of the valve seat member 200 and the valve body 207 is very complex, and the processing costs are high, which leads to the problem of high manufacturing costs for the valve.

[0012] Therefore, the present invention aims to provide valves and buffers that can reduce manufacturing costs.

[0013] To achieve the above objective, the valve of the present invention comprises: a valve seat member which is annular and has a seat portion on its inner circumference; a guide member which has an aligning shaft inserted into the valve seat member and is alignable with respect to the valve seat member; a valve body which slides against the outer circumference of the aligning shaft and is movable in the axial direction relative to the valve seat member and seats away from the seat portion; an annular disc spring which is interposed between the outer circumference of the valve seat member and the valve body and biases the valve body in a direction away from the seat portion; and an actuator which can apply a thrust to the valve body in a direction that causes the valve body to seat on the seat portion.

[0014] With a valve configured in this way, a self-aligning shaft is inserted through the inner circumference of the valve seat member and a guide member is combined with the valve seat member to form a passage that is opened and closed by the valve body. At the same time, the valve body is brought into sliding contact with the outer circumference of the self-aligning shaft to guide the movement of the valve body. By distributing the functions of passage formation, valve body alignment, and valve body guidance among the valve seat member, guide member, and valve body, it is not necessary to concentrate multiple functions such as passage formation, valve body alignment, and valve body guidance on the valve seat member.

[0015] Furthermore, the buffer includes a cylinder, a piston that is movably inserted into the cylinder and divides the cylinder into an extension chamber and a compression chamber filled with liquid, a rod connected to the piston, a reservoir for storing liquid, an extension check valve that allows liquid flow only from the reservoir to the compression chamber, a compression check valve that allows liquid flow only from the compression chamber to the extension chamber, a discharge passage connecting the extension chamber and the reservoir, and a valve provided in the discharge passage with the extension chamber upstream and the reservoir downstream.

[0016] With a shock absorber configured in this way, liquid is always discharged from the cylinder through the discharge passage to the reservoir as it expands and contracts, resulting in a uniflow type shock absorber. Since resistance to this liquid flow is provided by a valve, both the extension and compression damping forces of the shock absorber can be adjusted by adjusting the amount of current supplied to the solenoid, and since the valve is inexpensive, manufacturing costs can be reduced.

[0017] Figure 1 is a cross-sectional view of a valve in one embodiment. Figure 2 is a cross-sectional view of a buffer to which the valve in one embodiment is applied. Figure 3 is an enlarged cross-sectional view of a part of the valve in one embodiment. Figure 4 is an enlarged cross-sectional view of the actuator portion of the valve in one embodiment. Figure 5 is a cross-sectional view of a conventional valve.

[0018] The present invention will be described below based on an illustrated embodiment. In this embodiment, as shown in Figure 1, the valve 1 comprises an annular valve seat member 2 having a seat portion 2b, a guide member 3 having a self-aligning shaft 3a inserted into the valve seat member 2 and aligned with respect to the valve seat member 2, a valve body 4 that slides against the outer circumference of the self-aligning shaft 3a and is movable in the axial direction relative to the valve seat member 2, an annular disc spring 5 interposed between the outer circumference of the valve seat member 2 and the valve body 4 to bias the valve body 4 away from the seat portion 2b, and a solenoid S as an actuator capable of applying thrust to the valve body 4 in the direction of seating the valve body 4 on the seat portion 2b. This valve 1 is applied to a shock absorber 100, and when the shock absorber 100 expands and contracts, it provides resistance to the liquid passing between the seat portion 2b and the valve body 4, and can control the opening pressure of the main valve 20 by adjusting the back pressure acting on the back surface of the main valve 20.

[0019] The shock absorber 100 to which this valve 1 is applied is configured, for example, as shown in Figure 2, to include a cylinder 101, a piston 102 slidably inserted into the cylinder 101, a rod 103 that is movable into the cylinder 101 and connected to the piston 102, an extension chamber 104 and a compression chamber 105 partitioned by the piston 102 inserted into the cylinder 101, an intermediate cylinder 107 that covers the outer circumference of the cylinder 101 and forms a discharge passage 106 between it and the cylinder 101, an outer cylinder 109 that covers the outer circumference of the intermediate cylinder 107 and forms a reservoir 108 between it and the intermediate cylinder 107, a main valve 20, and a valve 1 that controls the opening pressure of the main valve 20. The extension chamber 104 and the compression chamber 105 are filled with liquid, and the reservoir 108 stores liquid and also contains gas. In this embodiment, the shock absorber 100 uses hydraulic oil as the liquid, but any liquid that can exert damping force using the valve 1 can be used instead of hydraulic oil.

[0020] In the case of this buffer 100, it includes an extension damping valve 110 provided on the piston 102 to resist the flow of liquid from the extension chamber 104 to the compression chamber 105, a compression check valve 111 provided on the piston 102 to allow only the flow of liquid from the compression chamber 105 to the extension chamber 104, a compression damping valve 112 to resist the flow of liquid from the compression chamber 105 to the reservoir 108, and an extension check valve 113 to allow only the flow of liquid from the reservoir 108 to the compression chamber 105. The discharge passage 106 connects the extension chamber R1 and the reservoir R via a hole 101a provided in the cylinder 101 to the extension chamber 104 and via a hole 107a provided in the intermediate cylinder 107 to the reservoir 108. The main valve 20 is provided in the middle of the discharge passage 106.

[0021] Therefore, when the shock absorber 100 is in compression operation, the piston 102 moves downward in Figure 2, compressing the compression chamber 105. The liquid in the compression chamber 105 flows to the reservoir 108 through the compression damping valve 112 and also moves to the extension chamber 104 through the compression check valve 111. During this compression operation, the rod 103 enters the cylinder 101, resulting in an excess of liquid in the cylinder 101 due to the volume of the rod's entry. A portion of this excess liquid is pushed out of the cylinder 101 and discharged to the reservoir 108 via the discharge passage 106. The main valve 20, located in the discharge passage 106, provides resistance to the flow of liquid moving through the discharge passage 106 to the reservoir 108. Thus, when the shock absorber 100 is in contraction operation, the compression damping valve 112 and the main valve 20 increase the pressure inside the cylinder 101, thereby exerting a compression damping force. Furthermore, the valve 1 allows adjustment of the back pressure acting on the back of the main valve 20, and the damping force generated when the shock absorber 100 contracts can be adjusted.

[0022] Conversely, when the buffer 100 extends, the piston 102 moves upward in Figure 2, compressing the extension chamber 104. The liquid in the extension chamber 104 moves to the compression chamber 105 via the extension damping valve 110 and also to the reservoir 108 via the discharge passage 106. During this extension operation, the piston 102 moves upward, expanding the volume of the compression chamber 105, and liquid corresponding to this expansion is supplied from the reservoir 108 via the extension check valve 113. The buffer 100 then resists the flow of liquid moving from the extension chamber 104 to the compression chamber 105 with the extension damping valve 110, and resists the flow of liquid moving through the discharge passage 106 to the reservoir 108 with the main valve 20, thereby increasing the pressure in the extension chamber 104 and exerting an extension damping force. Furthermore, the valve 1 allows adjustment of the back pressure acting on the back of the main valve 20, and the damping force generated when the shock absorber 100 extends can be adjusted.

[0023] Furthermore, the shock absorber 100 is set to be a biflow type in which liquid flows back and forth between the extension chamber 104 and the compression chamber 105 during extension and contraction operation, and liquid also passes through the main valve 20 provided in the discharge passage 106, allowing the damping force generated to be adjusted by adjusting the opening pressure of the main valve 20. The shock absorber 100 may also be set to be a uniflow type shock absorber in which the extension damping valve 110 and the compression damping valve 112 are eliminated, and when extension and contraction operation occurs, liquid is always discharged from inside the cylinder 101 through the discharge passage 106 to the reservoir 108, and the liquid circulates sequentially in one direction through the compression chamber 105, extension chamber 104, and reservoir 108, in which case the damping force on both the extension and compression sides is generated by the main valve 20. As described above, valve 1 can control the opening pressure of the main valve 20 by adjusting the back pressure acting on the back of the main valve 20 according to the amount of current supplied to the solenoid S, and can adjust the damping force generated when the shock absorber 100 expands and contracts.

[0024] The main valve 20 includes a valve retaining member 21 fitted into a collar 107b surrounding the outer circumference of a hole 107a provided on the side of the intermediate cylinder 107, a disc 22 having a port 22a and an annular valve seat 22b surrounding the port 22a, an annular leaf valve 23 mounted on the outer circumference of the valve retaining member 21 and opening and closing the port 22a by seating its front side against the annular valve seat 22b, a cylindrical housing 24 connected to the valve retaining member 21 and positioned on the rear side of the leaf valve 23, an annular spool 26 that abuts against the rear side of the leaf valve 23 and is slidably inserted into the inner circumference of the housing 24 to form a back pressure chamber 25 that acts inward on the leaf valve 23 together with the housing 24, an annular spring 27 that biases the spool 26 in the direction of abutting against the leaf valve 23, and a pilot passage 28 provided inside the valve retaining member 21 and the housing 24 to guide the pressure on the upstream side of the port 22a to the back pressure chamber 25. Furthermore, valve 1 is located downstream of the pilot passage 28 and adjusts the pressure in the back pressure chamber 25 according to the amount of current supplied to the solenoid S.

[0025] The main valve 20 and the valve 1 of this embodiment will now be described in detail. As shown in Figure 3, the main valve 20 is fitted into a cylindrical collar 107b that surrounds the outer circumference of a hole 107a provided on the side of the intermediate cylinder 107, and the valve 1 is housed in a cylindrical sleeve 109b provided on the side of the outer cylinder 109 that surrounds the outer circumference of a hole 109a through which the main valve 20 is inserted, and a cylindrical case 70 attached to the outer circumference of the sleeve 109b.

[0026] As shown in Figure 3, the valve retaining member 21 is configured to include a fitting portion 21a that fits into the collar 107b, a flange 21b that has a larger diameter than the fitting portion 21a, a shaft portion 21c that protrudes to the right in Figure 3 from the flange 21b and has a threaded portion (not shown) on the outer circumference of its right end in Figure 3, a hollow portion 21d that extends from the left end of the fitting portion 21a to the right end of the shaft portion 21c and forms part of the pilot passage 28, and a plurality of passages 21e that open from the hollow portion 21d and lead to the right end of the flange 21b in Figure 3.

[0027] As described above, passage 21e is connected to the hollow section 21d, and furthermore, since the hollow section 21d is connected to the discharge passage 106 through the hole 107a, it is connected to the extension chamber 104 via the discharge passage 106. In addition, the opening on the right end side of the flange 21b in passage 21e in Figure 3 is connected to the reservoir 108. In other words, in the case of this shock absorber 100, when it expands or contracts, hydraulic fluid is discharged from the extension chamber 104 to the reservoir 108 via the discharge passage 106 and passage 21e, and the upstream of passage 21e is the extension chamber 104.

[0028] Furthermore, a sealing ring 21f is fitted to the outer circumference of the fitting portion 21a of the valve holding member 21, which is in close contact with the inner circumference of the collar 107b. This seals the space between the outer circumference of the fitting portion 21a and the collar 107b, preventing the discharge passage 106 from passing through the space between the fitting portion 21a and the collar 107b to the reservoir 108.

[0029] Next, a disc 22 is stacked on the right end of the flange 21b of the valve retaining member 21 in Figure 3. This disc 22 seats on and off the flange 21b to open and close the passage 21e. The disc 22 is annular in shape and has multiple ports 22a that penetrate its thickness axially, and an annular valve seat 22b provided on the back side opposite the valve retaining member, surrounding the outer circumference of the ports 22a and protruding to the back side. Furthermore, the disc 22 has an annular projection 22c that protrudes toward the flange 21b from the end of the valve retaining member 21 facing the flange 21b. The annular projection 22c is located on the outer circumference side of the opening of the passage 21e in the flange 21b, and when the disc 22 contacts the flange 21b, the annular projection 22c seats toward the outer circumference side of the passage 21e in the flange 21b. Therefore, when the disc 22 contacts the flange 21b, the outlet end of the passage 21e is closed by the disc 22. Furthermore, the port 22a is designed to resist the flow of hydraulic fluid passing through it. As will be described in more detail later, when the hydraulic fluid that has passed through the passage 21e passes through the port 22a and moves to the back side of the disc 22, a pressure difference is created between the front side of the disc 22, which is the valve holding member 21 side, and the back side. In the main valve 20, an annular projection 22c is provided on the disc 22, but a valve seat surrounding the outer circumference of the passage 21e may be provided on the flange 21b of the valve holding member 21.

[0030] The disc 22 is slidably mounted on the outer circumference of an annular guide 30, which is mounted on the outer circumference of the base end of the shaft portion 21c of the valve retaining member 21. The disc 22 can move axially, in the left-right direction in Figure 3, by sliding against the outer circumference of the guide 30 mounted on the outer circumference of the base end of the shaft portion 21c. In this way, the disc 22 is assembled in a floating state relative to the valve retaining member 21, and can seat on and off the flange 21b by moving closer to and further away from the valve retaining member 21, and when it seats off the flange 21b, it opens the passage 21e. In addition, a notched orifice 22d is provided in the annular valve seat 22b. The orifice may be provided in the valve retaining member 21 or in the annular projection 22c of the disc 22 instead of the notched orifice 22d.

[0031] Furthermore, a leaf valve 23 is stacked on the back side of the disc 22. This leaf valve 23 is a stacked leaf valve composed of multiple annular plates, and its inner circumference is assembled to the shaft portion 21c and sandwiched between a guide 30 mounted on the outer circumference of the base end of the shaft portion 21c and a housing 24 screwed to the shaft portion 21c. Therefore, the leaf valve 23 is allowed to deflect on its outer circumference and can seat and dissipate from the annular valve seat 22b of the disc 22. The outer diameter of the annular plates in the leaf valve 23 decreases in stages as they are stacked towards the back side.

[0032] Furthermore, the inner circumference of the leaf valve 23 is stacked on the guide 30 and fixed to the shaft portion 21c, while the outer circumference is seated on the annular valve seat 22b that protrudes from the back surface of the disc 22 toward the leaf valve 23. There is a space between the leaf valve 23 and the disc 22, in which an intermediate chamber 29 is formed. The intermediate chamber 29 is connected to the passage 21e via a port 22a. When the leaf valve 23 flexes due to the pressure acting on the intermediate chamber 29 via the port 22a and separates from the annular valve seat 22b, an annular gap is formed between it and the disc 22, allowing the hydraulic fluid that has passed through the passage 21e and port 22a to move between the leaf valve 23 and the disc 22 to the reservoir 108. In other words, even if the disc 22 is seated on the flange 21b, when the leaf valve 23 flexes and separates from the annular valve seat 22b, the port 22a opens, allowing the hydraulic fluid to move from the extension chamber 104 to the reservoir 108.

[0033] Furthermore, as the leaf valve 23 flexes and the disc 22 is pushed up by the pressure from the passage 21e, the entire disc 22 slides on the shaft portion 21c and separates from the flange 21b. In this case, the hydraulic fluid that has passed through the passage 21e is discharged to the reservoir 108 through the annular gap created between the disc 22 and the flange 21b. The leaf valve 23 is configured as a laminated leaf valve with multiple annular plates stacked on top of each other, but the number of annular plates is arbitrary.

[0034] Then, the housing 24 is screwed onto the right end of the shaft portion 21c, which is the tip of the shaft portion 21c in Figure 3. As a result, the leaf valve 23 assembled to the shaft portion 21c is held and fixed between the guide 30, which is mounted on the outer circumference of the shaft portion 21c of the valve holding member 21, and the housing 24.

[0035] As shown in Figure 3, the housing 24 includes an inner cylinder 24a having a threaded portion (not shown) on its inner circumference and being screwed onto the shaft portion 21c of the valve holding member 21; an outer cylinder 24b facing the inner cylinder 24a with an annular gap between them; a flange-shaped bottom portion 24c protruding radially from the outer circumference of the right end of the inner cylinder 24a in Figure 3 and connected to the right end of the outer cylinder 24b in Figure 3; a cylindrical socket 24d rising from the side of the bottom portion 24c opposite the inner cylinder and having a threaded portion (not shown) on its outer circumference; and an orifice 24e passing through the bottom portion 24c and leading into the inner cylinder 24a.

[0036] The inner cylinder 24a of the housing 24, when screwed onto the shaft portion 21c of the valve retaining member 21, cooperates with the guide 30 to clamp the leaf valve 23. The outer diameter of the outer circumference of the inner cylinder 24a in the housing 24 is larger at the base end, which is the right end in Figure 3, forming a stepped portion. A spring seat 24f is provided at this stepped portion, facing the back surface of the leaf valve 23. This spring seat 24f functions as a spring support that supports the inner circumference of the spring 27. The inner circumference side of the inner cylinder 24a of the housing 24 is connected to the hollow portion 21d of the valve retaining member 21. Furthermore, a longitudinal groove 24g is provided on the outer circumference of the socket 24d of the housing 24, running axially.

[0037] As shown in Figure 3, a spool 26 is slidably inserted into the inner circumference of the outer cylinder 24b. The spool 26 is cylindrical and movable axially relative to the housing 24, and its left end in Figure 3 abuts against the outer circumference of the back surface of the leaf valve 23, working in cooperation with the housing 24 to form a back pressure chamber 25 on the right end in Figure 3, which is the back side of the leaf valve 23. The back pressure chamber 25 is connected to the inside of the inner cylinder 24a via an orifice 24e provided in the bottom 24c of the housing 24. As described above, since the inside of the housing 24 is connected to the extension chamber 104, the hydraulic fluid discharged from the extension chamber 104 is guided to the back pressure chamber 25 via the hollow section 21d and the orifice 24e. The hollow section 21d forms a pilot passage 28, and the pressure upstream of the passage 21e is introduced into the back pressure chamber 25 via the pilot passage 28 and the orifice 24e.

[0038] The spring 27 is an annular disc spring, with its inner circumference on the side opposite the leaf valve supported by a spring seat 24f provided on the housing 24, and its outer circumference on the leaf valve side supported by the right end of the spool 26 in Figure 3. When the disc 22 is seated on the flange 21b of the valve holding member 21 and the spool 26 is in contact with the leaf valve 23, in the axial direction of the spool 26, the support surface of the spring 27 on the spring seat 24f of the housing 24 is positioned closer to the leaf valve than the right end face of the spool 26 in Figure 3. Therefore, the spring 27 is interposed between the spool 26 and the spring seat 24f in a deflected state with an initial deflection, constantly biasing the spool 26 in the direction of contact with the leaf valve 23.

[0039] Furthermore, as mentioned above, the hydraulic fluid discharged from the extension chamber 104 is guided to the back pressure chamber 25 via the pilot passage 28 and the orifice 24e. Therefore, in addition to the biasing force from the spring 27 that biases the spool 26, a biasing force acts on the back of the leaf valve 23 that pushes the leaf valve 23 toward the disc 22 due to the internal pressure of the back pressure chamber 25. In other words, when the shock absorber 100 expands and contracts, the disc 22 is subjected to the pressure from the front side via the passage 21e within the extension chamber 104, and from the back side via the leaf valve 23, the internal pressure of the back pressure chamber 25 and the biasing force from the spring 27 act on it.

[0040] Furthermore, a force equal to the value obtained by multiplying the pressure in the back pressure chamber 25 by the back pressure area, which is the area of ​​a circle with the outer diameter of the smallest diameter annular plate stacked on the top of the leaf valve 23 by the area of ​​a circle with the outer diameter of the spool 26 as its diameter, acts on the leaf valve 23 to press against the disc 22. A force equal to the value obtained by multiplying the pressure in the intermediate chamber 29 by the front pressure area, which is the area of ​​a circle with the inner diameter of the disc 22 by the area of ​​a circle with the inner diameter of the annular valve seat 22b as its diameter, acts on the leaf valve 23 in a direction that separates it from the disc 22. Therefore, the ratio of the back pressure area to the front pressure area of ​​the leaf valve 23 determines the pressure boosting ratio, which is the ratio of the opening pressure of the leaf valve 23 to the pressure in the back pressure chamber 25.

[0041] Then, the pressure in the extension chamber 104 increases the pressure in the intermediate chamber 29, and when the force that tries to bend the outer circumference of the leaf valve 23 to the right in Figure 3 overcomes the internal pressure of the back pressure chamber 25 and the biasing force of the spring 27, the leaf valve 23 bends and separates from the annular valve seat 22b, forming a gap between the leaf valve 23 and the disc 22 and opening the passage 21e. In this embodiment, the inner diameter of the annular valve seat 22b is larger than the inner diameter of the annular protrusion 22c, and there is a difference between the pressure-receiving area of ​​the disc 22 that receives pressure on the passage 21e side and the pressure-receiving area of ​​the disc 22 that receives pressure on the intermediate chamber 29 side. If the differential pressure generated by the port 22a does not reach the valve opening pressure that separates the disc 22 from the flange 21b of the valve holding member 21, the disc 22 remains seated on the flange 21b. On the other hand, when the leaf valve 23 is bent and in the open state, and the differential pressure generated by the port 22a reaches the opening pressure that causes the disc 22 to move away from the flange 21b, the disc 22 also moves away from the flange 21b and opens the passage 21e. In other words, the pressure boosting ratio in the leaf valve 23 is set to be smaller than the pressure boosting ratio in the disc 22, which is the ratio of the opening pressure of the disc 22 to the pressure in the intermediate chamber 29, so that the pressure in the extension chamber 104 when the leaf valve 23 opens is lower than the pressure in the extension chamber 104 when the disc 22 opens. That is, the opening pressure of the leaf valve 23 is set to be lower than the opening pressure of the disc 22.

[0042] Next, the valve 1 will be described in detail. As mentioned above, the valve 1 comprises a valve seat member 2 that is annular and has a seat portion 2b on its inner circumference, a guide member 3 that has an aligning shaft 3a inserted into the valve seat member 2 and is alignable with respect to the valve seat member 2, a valve body 4 that slides against the outer circumference of the aligning shaft 3a and is movable in the axial direction relative to the valve seat member 2 and seats away from the seat portion 2b, an annular disc spring 5 interposed between the outer circumference of the valve seat member 2 and the valve body 4 to bias the valve body 4 in a direction away from the seat portion 2b, and a solenoid S as an actuator capable of applying thrust to the valve body 4 in a direction that causes the valve body 4 to seat on the seat portion 2b. In addition, the valve 1 of this embodiment is equipped with a support ring 6 that is stacked on the side of the disc spring 5 opposite the valve seat member and sandwiches the outer circumference of the disc spring 5 together with the valve seat member 2.

[0043] The following describes each part of the valve 1 in detail. As shown in Figure 4, the valve seat member 2 is annular in shape overall and comprises a main body 2a having an annular seat portion 2b provided on the inner circumference of the right end, an annular projection 2c rising from the outer circumference of the right end of the main body 2a, and a fitting recess 2d which is an annular recess formed on the inner circumference of the left side of the main body 2a opposite the seat portion. The valve seat member 2 configured in this way is housed in the socket 24d of the housing 24 with the fitting recess 2d facing the main valve 20 side. More specifically, the valve seat member 2 has a flush outer circumference made up of the main body 2a and the annular projection 2c, and this outer circumference is fitted into the inner circumference of the socket 24d, so that the left end of the main body 2a in Figure 3 abuts against the bottom 24c of the housing 24. When the valve seat member 2 is housed in the socket 24d of the housing 24 in this way, it is positioned radially by the socket 24d.

[0044] The guide member 3 includes a columnar centering shaft 3a inserted into the inner circumference of the main body portion 2a of the valve seat member 2, a disc-shaped fitting portion 3b that is continuous with the proximal end of the centering shaft 3a and is fitted into the fitting recess 2d of the valve seat member 2, and a plurality of through holes 3c penetrating the fitting portion 3b in the axial direction. The centering shaft 3a has an outer diameter smaller than the inner diameter of the main body portion 2a of the valve seat member 2. It rises from the axial center of the fitting portion 3b and is inserted into the inner circumference of the valve seat member 2, and has a small-diameter portion 3a1 with a smaller outer diameter on the proximal end side. The outer diameter of the small-diameter portion 3a1 is sufficiently smaller than the inner diameter of the main body portion 2a of the valve seat member 2. When the fitting portion 3b is fitted into the fitting recess 2d and the centering shaft 3a is inserted into the main body portion 2a, the small-diameter portion 3a1 and the inner circumference of the main body portion 2a face each other in the radial direction, and a flow path of sufficient size can be secured between the small-diameter portion 3a1 and the main body portion 2a.

[0045] If a flow path of sufficient size can be secured between the outer circumference of the centering shaft 3a and the inner circumference of the main body portion 2a even without providing the small-diameter portion 3a1, the small-diameter portion 3a1 may not be provided on the centering shaft 3a. Further, since the through holes 3c provided in the fitting portion 3b communicate with the annular flow path between the centering shaft 3a and the main body portion 2a, even when the fitting portion 3b is fitted into the fitting recess 2d, the annular flow path between the centering shaft 3a and the main body portion 2a is not blocked by the fitting portion 3b.

[0046] In this way, when the guide member 3 is assembled to the valve seat member 2 by fitting the fitting portion 3b into the fitting recess 2d of the valve seat member 2, it is centered in the radial direction with respect to the valve seat member 2, so that the centering shaft 3a is positioned correctly in the radial direction with respect to the valve seat member 2.

[0047] The axial length of the fitting portion 3b substantially coincides with the depth of the fitting recess 2d of the valve seat member 2, and the outer diameter of the fitting portion 3b substantially coincides with the inner diameter of the fitting recess 2d, and the fitting portion 3b can be fitted into the fitting recess 2d. When the fitting portion 3b is fitted into the fitting recess 2d, the left end surface of the fitting portion 3b in FIG. 4 and the left end surface of the main body portion 2a of the valve seat member 2 in FIG. 4 are flush.

[0048] The fitting portion 3b is fitted into the fitting recess 2d of the valve seat member 2, and the centering shaft 3a is inserted into the main body portion 2a. After the guide member 3 is assembled to the valve seat member 2, when the valve seat member 2 with the guide member 3 assembled is housed in the socket 24d of the housing 24, the left end surface of the fitting portion 3b in FIG. 4 and the left end surface of the main body portion 2a of the valve seat member 2 in FIG. 4 are flush with each other. Therefore, the valve seat member 2 and the guide member 3 are placed on the bottom portion 24c of the housing 24 without play.

[0049] The valve body 4 is substantially cylindrical, and has an insertion hole 4a that opens from the left end in FIG. 4 and into which the centering shaft 3a is slidably inserted, a flange-shaped spring receiver 4b that projects radially from the side portion on the left side in FIG. 4, and a throttle passage 4c that opens from the side and communicates with the insertion hole 4a to communicate the insertion hole 4a to the outside. When the centering shaft 3a is inserted into the insertion hole 4a, a pressure chamber Pr is defined within the insertion hole 4a.

[0050] The valve body 4 is centered radially with respect to the guide member 3 and the valve seat member 2 by being inserted into the insertion hole 4a of the centering shaft 3a, and can move in the left-right direction in FIG. 4, which is the axial direction, using the centering shaft 3a as a guide. The outer diameter of the left end of the valve body 4 in FIG. 4 is larger than the inner diameter of the main body portion 2a, and when the valve body 4 is closest to the valve seat member 2, the left end can be seated on the seat portion 2b of the valve seat member​​The pressure chamber Pr, formed by the slidable insertion of the self-aligning shaft 3a into the insertion hole 4a of the valve body 4, expands and contracts in volume when the valve body 4 moves axially relative to the self-aligning shaft 3a. Since the pressure chamber Pr is in communication with the outside of the valve body 4 via a throttling passage 4c provided in the valve body 4, when the volume expands and contracts, hydraulic fluid moves back and forth between the outside of the valve body 4 and the pressure chamber Pr through the throttling passage 4c. However, the throttling passage 4c provides resistance to the flow of hydraulic fluid, slowing down the movement of the valve body 4 toward and away from the valve seat member 2, and suppressing vibration and sudden displacement of the valve body 4. Therefore, pressure fluctuations caused by sudden displacement of the valve body 4 are suppressed, and the valve 1 can provide stable resistance to the flow of hydraulic fluid passing through it.

[0052] Furthermore, an annular disc spring 5 is interposed between the left end of the spring receiver 4b of the valve body 4 in Figure 4 and the right end of the annular projection 2c of the valve seat member 2 in Figure 4, and the valve body 4 is biased by the disc spring 5 in the direction of seating on the seat portion 2b.

[0053] As shown in Figure 4, the disc spring 5 comprises an annular outer circumference 5a and five arms 5b extending inward from the inner circumference of the outer circumference 5a. The outer circumference 5a is supported by an annular projection 2c, and the tip of each arm 5b is supported by a spring receiver 4b, and the disc spring 5 is interposed between the valve body 4 and the valve seat member 2.

[0054] An annular support ring 6 is stacked on the right side of Figure 4, which is the side of the disc spring 5 opposite the valve seat member. The outer diameter of the support ring 6 is such that it can be fitted to the inner circumference of the socket 24d without any play, and when inserted into the socket 24d, it is radially centered by the socket 24d together with the valve seat member 2. When the support ring 6 is stacked on the disc spring 5 and inserted into the socket 24d together with the valve seat member 2, guide member 3 and disc spring 5, the right end in Figure 4 protrudes out of the socket 24d and comes into contact with the second fixed iron core 44 of the solenoid S, which will be described later. Therefore, the support ring 6 is held in place within the socket 24d by being sandwiched between the solenoid S and the bottom 24c together with the valve seat member 2, guide member 3 and disc spring 5.

[0055] When the support ring 6, valve seat member 2, guide member 3, and disc spring 5 are sandwiched between the solenoid S and the bottom portion 24c, the disc spring 5 is fixedly supported by the annular projection 2c of the valve seat member 2 and the support ring 6, and deflection of the multiple arms 5b protruding from the inner circumference of the outer circumference 5a is permitted. In the axial direction of the valve seat member 2, the support position of the outer circumference 5a is positioned on the side opposite the valve seat than the support position of the arms 5b by the spring receiver 4b when the valve body 4 is seated on the seat portion 2b, so the arms 5b deflect toward the valve seat member 2, and the disc spring 5 exerts a biasing force in the direction that separates the valve body 4 from the seat portion 2b.

[0056] Furthermore, the support ring 6 is provided with a plurality of notches 6a that open on the end opposite the socket. Since the notches 6a are provided on the portion of the support ring 6 that protrudes outside the socket 24d, the inside of the socket 24d and the outside of the socket 24d are always in communication. The notches 6a in the support ring 6 form a flow path on the downstream side of the valve 1. The number of notches 6a installed on the support ring 6 may be one or more, as long as the notches 6a can function as a flow path on the downstream side of the valve 1. When the support ring 6, valve seat member 2, guide member 3 and disc spring 5 are fixed to the housing 24, the through hole 3c is connected to the hollow portion 21d, so the pilot passage 28 is connected to the reservoir R via the through hole 3c, the notches 6a and the vertical groove 24g formed on the outer circumference of the socket 24d.

[0057] The solenoid S, acting as an actuator, applies a thrust to the valve body 4 in a direction that causes the valve body 4 to seat on the seat portion 2b, and adjusts the thrust that presses the valve body 4 against the seat portion 2b in opposition to the disc spring 5, thereby adjusting the opening pressure of the valve 1.

[0058] Specifically, as shown in Figure 4, the solenoid S comprises a resin-molded cylindrical coil 41, a cylindrical body 42 made of a non-magnetic material fitted to the inner circumference of the coil 41, a first fixed core 43 that abuts against the right end of the coil 41 in Figure 4 and is fitted to the inner circumference of the right end of the body 42 in Figure 4, a second fixed core 44 that abuts against the left end of the coil 41 in Figure 4 and is fitted to the inner circumference of the left end of the body 42 in Figure 4 with a gap between it and the first fixed core 43, and the first The valve comprises a first movable core 45 and a second movable core 46, which are arranged between the fixed core 43 and the second fixed core 44 so as to be movable in the axial direction in Figure 4, a spring 47 that biases the first movable core 45 toward the valve body 4 side of the valve 1 to the left in Figure 4, an annular first restricting member 48 that prevents the first movable core 45 and the second movable core 46 from being attracted to each other, and a second restricting member 49 that prevents the second movable core 46 and the second fixed core 44 from being attracted to each other.

[0059] The coil 41 is integral with a coupler 60 that is molded in a cylindrical shape from resin and houses terminals 61 electrically connected to the coil 41, and is positioned on the outer circumference of the first movable core 45 and the second movable core 46. A cylindrical body 42 made of a non-magnetic material is fitted to the inner circumference of the coil 41. The cylindrical body 42 has an annular flange 42a that protrudes inward from the inner circumference on the left end side in Figure 4.

[0060] The first fixed core 43 is made of a magnetic material and includes a bottomed cylindrical base 43a that fits onto the inner circumference of the cylindrical body 42, a flange 43b provided on the outer circumference of the rear end of the base 43a and abutting against the right end of the cylindrical body 42 in Figure 4, and an annular groove 43c provided on the outer circumference of the base 43a. A seal ring 50 is installed in the annular groove 43c, and when the base 43a is fitted into the cylindrical body 42, the seal ring 50 makes close contact with the inner circumference of the cylindrical body 42, sealing the space between the first fixed core 43 and the cylindrical body 42.

[0061] The second fixed iron core 44 is made of a magnetic material and includes an annular base 44a that abuts the left end of the resin-molded coil 41 in Figure 4, an annular fitting cylinder 44b that rises from the inner circumference of the right end of the base 44a in Figure 4 and fits into the inner circumference of the cylindrical body 42, and a cylindrical connecting cylinder portion 44c that rises from the outer circumference of the left end of the base 44a in Figure 4.

[0062] The fitting cylinder 44b is provided with an annular projection 44b1 that protrudes axially from the right end in Figure 4. The outer circumference of the projection 44b1 is tapered, and a seal ring 51 is provided between the outer circumference of the projection 44b1 and the flange 42a of the cylindrical body 42, sealing the space between the second fixed iron core 44 and the cylindrical body 42.

[0063] Furthermore, screw grooves are provided on the inner and outer circumferences of the connecting cylinder portion 44c. The inner circumference of the connecting cylinder portion 44c is screw-connected to the screw portion on the outer circumference of the socket 24d of the housing 24, and the outer circumference of the connecting cylinder portion 44c is screw-connected to the inner circumference of the sleeve 109b of the outer cylinder 109 of the buffer 100. A seal ring 52 is provided between the connecting cylinder portion 44c and the sleeve 109b, sealing the space between the second fixed core 44 and the sleeve 109b. When the second fixed core 44 is screw-connected to the socket 24d of the housing 24, the right end of the valve body 4 housed in the housing 24 is inserted into the base 44a and then into the cylinder 42.

[0064] A cylindrical case 70 housing the solenoid S is attached to the sleeve 109b. After the case 70 is fitted onto the outer circumference of the sleeve 109b, it is plastically deformed by crimping from the outer circumference side and fixed to the outer circumference of the sleeve 109b. The case 70 has a notch 70a that opens at the right end in Figure 4, and a coupler 60, which is integrated with the coil 41 with molded resin, protrudes out of the case 70 through the notch 70a.

[0065] When the second fixed core 44 is screwed into the socket 24d of the housing 24, the valve seat member 2, guide member 3, disc spring 5, and support ring 6 are held between the second fixed core 44 and the bottom portion 24c and fixed within the socket 24d, as described above.

[0066] Furthermore, a first movable core 45 and a second movable core 46 are slidably inserted between the first fixed core 43 and the second fixed core 44 on the inner circumference of the cylindrical body 42. The first movable core 45 comprises a sliding contact cylinder 45a made of a soft magnetic material that slides against the inner circumference of the cylindrical body 42, and a cylindrical spring support cylinder 45b made of a non-magnetic material that is positioned inside the sliding contact cylinder 45a. The sliding contact cylinder 45a has an annular flange portion 45a1 at its right end in Figure 4 that protrudes inward and to which the spring support cylinder 45b is attached, and its outer circumference slides against the inner circumference of the cylindrical body 42. The first movable core 45 can move within the cylindrical body 42 in the axial direction (left-right in Figure 4) using the cylindrical body 42 as a guide.

[0067] The second movable core 46 is made of a soft magnetic material and has a bottomed cylindrical shape with a cylindrical portion 46a and a bottom portion 46b that closes the left end of the cylindrical portion 46a in Figure 4. The outer circumference of the cylindrical portion 46a is in sliding contact with the inner circumference of the sliding contact cylinder 45a of the first movable core 45. The inner diameter of the cylindrical portion 46a is larger than the outer diameter of the spring support cylinder 45b of the first movable core 45. Therefore, the movement of the second movable core 46 is guided by the sliding contact cylinder 45a of the first movable core 45 with which the cylindrical portion 46a slides, and it can move relative to the first movable core 45 in the axial direction. Since the outer circumference of the sliding contact cylinder 45a of the first movable core 45 is in sliding contact with the cylindrical body 42, both the first movable core 45 and the second movable core 46 can move in the axial direction without axial wobble relative to the cylindrical body 42. Furthermore, the outer circumference of the bottom portion 46b of the second movable core 46 is always in contact with the inner circumference of the fitting cylinder 44b of the second fixed core 44.

[0068] Furthermore, the spring 47 is interposed between the spring support cylinder 45b of the first movable core 45 and the bottom of the base 43a of the first fixed core 43, biasing the first movable core 45 toward the left in Figure 4, which is the valve body 4 side.

[0069] A first restricting member 48, made of a non-magnetic material, is placed on the flange portion 45a1 of the sliding contact cylinder 45a of the first movable core 45. The first restricting member 48 prevents the flange portion 45a1 of the first movable core 45 and the cylinder portion 46a of the second movable core 46 from directly contacting and attracting each other. In addition, a second restricting member 49, made of a non-magnetic material, is placed inside the fitting cylinder 44b of the base 44a of the second fixed core 44. The second restricting member 49 prevents the second movable core 46 and the second fixed core 44 from directly contacting and attracting each other.

[0070] As mentioned above, the first fixed core 43, the second fixed core 44, the sliding contact cylinder 45a of the first movable core 45, and the second movable core 46 are each made of soft magnetic material and form a magnetic path in the solenoid S. Therefore, when current is applied to the coil 41, the magnetic field generated in the coil 41 returns to the coil 41 through the sliding contact cylinder 45a of the first fixed core 43, the second fixed core 44, the first movable core 45, and the second movable core 46. Consequently, when current is applied to the coil 41, the first movable core 45 is attracted to the first fixed core 43 located on the right side of Figure 1, and the second movable core 46 is attracted to the second fixed core 44 located on the left side of Figure 1. In other words, when current is applied to the coil 41 in the solenoid S, the first movable core 45 and the second movable core 46 are attracted to each other in a direction that separates them axially.

[0071] The components of the solenoid S, excluding the resin-molded cylindrical coil 41, are assembled together with the components of the valve 1 and main valve 20 to form a valve assembly. The valve assembly is housed in the collar 107b and sleeve 109b and fixed to the sleeve 109b by screw fastening of the second fixed iron core 44 to the sleeve 109b. After fixing the valve assembly in the sleeve 109b in this manner, the coil 41, which is integrated with the coupler 60 by molded resin, is inserted into the case 70, and the coupler 60 is made to protrude from the case 70 through the notch 70a. Then, a disc-shaped cap 71 is attached to the open end at the right end of the case 70 in Figure 4 by crimping, and the assembly of the valve 1 and main valve 20 to the buffer 100 is completed.

[0072] When valve 1 and main valve 20 are mounted on the buffer 100 in this manner, the bottom 46b of the second movable core 46 comes into contact with the right end of the valve body 4 in Figure 1. Therefore, the thrust generated by the solenoid S is transmitted to the valve body 4 which is in contact with the second movable core 46.

[0073] When the solenoid S is not energized, the spring 47 causes the first movable core 45 to abut against the second movable core 46, thereby biasing the valve body 4 toward the valve seat member 2 via the second movable core 46, against the biasing force of the disc spring 5. In this way, when the solenoid S is not energized, the valve body 4 seats on the seat portion 2b due to the biasing force of the spring 47, and the valve 1 closes. Then, when the pressure on the upstream side of the valve 1 in the pilot passage 28 pushes the valve body 4 in the opening direction, exceeding the biasing force of the spring 47, the valve 1 opens. Therefore, when the solenoid S is not energized, the opening pressure of the valve 1 is set by the biasing force of the spring 47, and the pressure in the back pressure chamber 25 also becomes equal to the opening pressure of the valve 1 set by the biasing force of the spring 47.

[0074] Furthermore, when current is supplied to the coil 41, the first movable core 45 is attracted by the first fixed core 43, and the second movable core 46 is attracted by the second fixed core 44. When the current supplied to the coil 41 is increased, the attractive force of the first fixed core 43 attracting the first movable core 45 exceeds the biasing force of the spring 47, causing the second movable core 46 and the first movable core 45 to separate and the first movable core 45 to come into close contact with the first movable core 45 and the first fixed core 43. At the same time, the attractive force of the second fixed core 44 attracting the second movable core 46 increases, and the force pressing the valve body 4 toward the seat portion 2b side against the biasing force of the disc spring 5 increases. When the first movable core 45 is attracted to the first fixed core 43 in this manner, the solenoid S causes the attractive force between the second movable core 46 and the second fixed core 44 to be proportional to the amount of current supplied to the coil 41, thereby applying a thrust to the valve body 4 in the valve closing direction that is proportional to the amount of current supplied to the coil 41.

[0075] Thus, the valve body 4 is biased in the opening direction by the disc spring 5, while receiving thrust from the solenoid S in the closing direction. By adjusting the thrust of the solenoid S, the pressure at which the valve body 4 separates from the valve seat member 2 due to the pressure received from the pilot passage 28, that is, the opening pressure of the valve 1, can be adjusted. Since the pressure upstream of the valve body 4 in the pilot passage 28 is equal to the opening pressure of the valve 1, the pressure in the back pressure chamber 25 connected to the pilot passage 28 is also equal to the opening pressure of the valve 1. Therefore, the pressure in the back pressure chamber 25 can be controlled by adjusting the thrust of the solenoid S.

[0076] In normal operation when the solenoid S can be energized, the valve opening pressure of the valve 1 can be adjusted according to the amount of current supplied to the coil 41 by adjusting the thrust that the solenoid S exerts on the valve body 4 due to the magnetic force generated by the energization of the solenoid S. In a failure state where the solenoid S cannot be energized, the solenoid S can exert thrust on the valve body 4 by the biasing force of the spring 47, so the valve opening pressure of the valve 1 becomes the opening pressure set by the biasing force of the spring 47. In this embodiment, the actuator is a solenoid, but any actuator other than a solenoid may be used as long as it can exert thrust on the valve body 4 and adjust the valve opening pressure of the valve 1.

[0077] The operation of the buffer 100 equipped with valve 1 and main valve 20 according to this embodiment will be described below. When the buffer 100 expands and contracts and hydraulic fluid is discharged from the expansion chamber 104 through the main valve 20 to the reservoir 108, if valve 1 is operating normally, the pressure upstream of passage 21e and pilot passage 28 increases, supplying current to the solenoid S to adjust the opening pressure of valve 1, and the pressure upstream of valve 1 in the pilot passage 28 is guided to the back pressure chamber 25.

[0078] The internal pressure of the back pressure chamber 25 is controlled by the opening pressure of the valve 1, and by adjusting this opening pressure with the solenoid S, the pressure acting on the back of the leaf valve 23 can be adjusted, and consequently, the opening pressure at which the leaf valve 23 opens the passage 21e can be controlled.

[0079] More specifically, the pressure in the extension chamber 104 increases the pressure in the intermediate chamber 29, and when this force attempts to bend the outer circumference of the leaf valve 23 to the right in Figure 3, it overcomes the internal pressure of the back pressure chamber 25 and the biasing force of the spring 27, causing the leaf valve 23 to bend and separate from the annular valve seat 22b, creating a gap between the leaf valve 23 and the disc 22 and opening the passage 21e. Therefore, by adjusting the pressure in the back pressure chamber 25 with the valve 1, the pressure in the intermediate chamber 29 that can separate the leaf valve 23 from the annular valve seat 22b can be adjusted. In other words, the opening pressure of the leaf valve 23 can be controlled by the amount of current supplied to the solenoid S. Therefore, the damping force characteristics of the shock absorber 100 (damping force characteristics with respect to piston speed) are such that, until the leaf valve 23 opens, the hydraulic fluid passes through the notched orifice 22d, resulting in a large damping coefficient characteristic of the orifice. However, when the leaf valve 23 separates from the annular valve seat 22b and opens the passage 21e, the characteristics change to those of the leaf valve, resulting in a smaller damping coefficient.

[0080] Furthermore, as mentioned earlier, since the pressure boosting ratio in the leaf valve 23 is smaller than the pressure boosting ratio in the disc 22, the opening pressure of the leaf valve 23 is smaller than the opening pressure of the disc 22. Therefore, unless the differential pressure generated by port 22a reaches the opening pressure that causes the disc 22 to move away from flange 21b, the disc 22 will remain seated on flange 21b. On the other hand, when the leaf valve 23 is bent and in the open state, the piston speed of the buffer 100 increases, and the differential pressure generated by port 22a reaches the opening pressure that causes the disc 22 to move away from flange 21b, the disc 22 will also move away from flange 21b and open the passage 21e. When the leaf valve 23 is open and the passage 21e communicates with the reservoir 108 only through port 22a, the disc 22 is separated from the flange 21b. As a result, the passage 21e communicates directly with the reservoir 108 without going through port 22a, and the flow area increases. Therefore, the damping force characteristics of the shock absorber 100 become less sloped compared to when only the leaf valve 23 is open, meaning the damping coefficient becomes even smaller.

[0081] By adjusting the amount of current supplied to the solenoid S, the opening pressure of valve 1 can be increased or decreased, thereby changing the damping force characteristics of the shock absorber 100. Furthermore, the pressure increase ratio in the leaf valve 23 can be made smaller than the pressure increase ratio in the disc 22, so that the opening pressure of the leaf valve 23 becomes smaller than the opening pressure of the disc 22, and the passage 21e is relieved in two stages. In this main valve 20, the damping force at full soft, when the opening pressure of valve 1 is at its minimum, can be reduced, and the variable range of the damping force can be increased.

[0082] Therefore, in the shock absorber 100 of this embodiment, the opening pressure of the valve 1 can be adjusted by adjusting the amount of current supplied to the solenoid S, thereby adjusting both the extension damping force during the extension operation of the shock absorber 100 and the compression damping force during the contraction operation. Furthermore, when the piston speed of the shock absorber 100 is in the low-speed range, a small damping force can be output, preventing excessive damping force, and when the piston speed is in the high-speed range, the upper limit of the hard damping force required can be increased, preventing insufficient damping force.

[0083] Furthermore, in the event of a failure, the current supply to the solenoid S is cut off. However, the solenoid S is equipped with a first movable core 45 and a second movable core 46, and even when de-energized, the spring 47 can provide thrust to the valve body 4 in the same direction as when energized. Therefore, according to the valve 1 of this embodiment, even in the event of a failure, the solenoid S can exert thrust to set the opening pressure of the leaf valve 23 in the main valve 20 to a predetermined value, thereby allowing the shock absorber 100 to exert sufficient damping force.

[0084] The valve 1 and the shock absorber 100 operate as described above. The valve 1 of this embodiment includes a valve seat member 2 which is annular and has a seat portion 2b on its inner circumference, a guide member 3 which has an aligning shaft 3a inserted into the valve seat member 2 and is alignable with respect to the valve seat member 2, a valve body 4 which slides against the outer circumference of the aligning shaft 3a and is movable in the axial direction relative to the valve seat member 2 and seats away from the seat portion 2b, an annular disc spring 5 interposed between the outer circumference of the valve seat member 2 and the valve body 4 and biasing the valve body 4 in a direction away from the seat portion 2b, and a solenoid (actuator) S capable of applying thrust to the valve body 4 in a direction that causes the valve body 4 to seat on the seat portion 2b.

[0085] With the valve 1 configured in this way, a passage that is opened and closed by the valve body 4 is formed by inserting the aligning shaft 3a through the inner circumference of the valve seat member 2 and combining the guide member 3 with the valve seat member 2, and the valve body 4 is slidably brought into contact with the outer circumference of the aligning shaft 3a to guide the movement of the valve body 4. This eliminates the need to concentrate numerous functions such as passage formation, valve body alignment, and valve body guiding on the valve seat member 2. Therefore, with the valve 1 of this embodiment, compared to a conventional valve structure in which numerous functions such as valve body alignment and guidance for the axial movement of the valve body 207, a valve seat equipped with an annular valve seat 206, and a component that forms inlet and outlet flow paths equipped with an inlet port 204 and an outlet port 205 are concentrated on the valve seat member 200, the functions of passage formation, valve body alignment, and valve body guiding can be distributed among the valve seat member 2, guide member 3, and valve body 4. As a result, the configuration of the valve seat member 2, guide member 3, and valve body 4 that constitute the valve 1 is simplified, and manufacturing costs can be reduced.

[0086] Furthermore, in conventional valves equipped with a structure that aligns the valve body 207 using a small-diameter cylindrical portion 201, the small-diameter cylindrical portion 201, which is the aligning part, is located on the side of the annular valve seat 206 opposite the valve body, resulting in the valve seat member 200 and the valve body 207 becoming elongated in the axial direction. However, in the valve 1 of this embodiment, the aligning shaft 3a that aligns the valve body 4 is located on the valve body 4 side relative to the valve seat member 2, so the length from the end of the valve seat member 2 opposite the valve body to the tip of the guide member 3 is shortened, allowing the valve 1 to be made smaller and thus reducing manufacturing costs.

[0087] Furthermore, in the valve 1 of this embodiment, the guide member 3 includes a disc-shaped fitting portion 3b having a through hole 3c that penetrates axially and fits onto the non-seat portion of the valve seat member 2, and an aligning shaft 3a whose outer diameter is smaller than the inner diameter of the valve seat member 2, rising from the fitting portion 3b and inserted into the inner circumference of the valve seat member 2. With the valve 1 configured in this way, the aligning shaft 3a can be aligned with respect to the valve seat member 2 by fitting the fitting portion 3b of the guide member 3 onto the valve seat member 2, and the valve seat member 2 and the guide member 3 can be assembled, thus simplifying the assembly of the valve 1.

[0088] Furthermore, in the valve 1 of this embodiment, the valve seat member 2 is annular and has an annular projection 2c on its outer circumference that supports the outer circumference of the disc spring 5, and is equipped with a support ring 6 that is stacked on the side of the disc spring 5 opposite the valve seat member and sandwiches the outer circumference of the disc spring 5 together with the valve seat member 2, and the support ring 6 is equipped with one or more notches 6a on the end opposite the leaf spring. With the valve 1 configured in this way, the disc spring 5 is fixedly supported by the support ring 6 and the annular projection 2c of the valve seat member 2, and the flow path on the downstream side of the valve 1 can be formed by the notches 6a provided in the support ring 6, and there is no need to provide a flow path on the downstream side of the valve 1 with respect to the valve seat member 2, further simplifying the structure of the valve seat member 2, reducing the processing cost of the valve seat member 2, and further reducing the overall manufacturing cost of the valve 1.

[0089] Furthermore, in the valve 1 of this embodiment, the valve body 4 has an insertion hole 4a into which the self-aligning shaft 3a is slidably inserted, and a throttling passage 4c that communicates the insertion hole 4a with the outside. When the self-aligning shaft 3a is inserted into the insertion hole 4a, a pressure chamber Pr is partitioned within the insertion hole 4a. With the valve 1 configured in this way, when the valve body 4 moves axially relative to the self-aligning shaft 3a, the pressure chamber Pr expands and contracts, and when the hydraulic fluid moves between the outside of the valve body 4 and the pressure chamber Pr through the throttling passage 4c, the throttling passage 4c provides resistance to the flow of the hydraulic fluid, thereby suppressing vibration and sudden displacement of the valve body 4 and providing stable resistance to the flow of the hydraulic fluid.

[0090] Furthermore, in the valve 1 of this embodiment, the solenoid (actuator) S provides thrust to the valve body 4 in proportion to the amount of current supplied, and provides a constant thrust to the valve body 4 when no power is supplied. With the valve 1 configured in this way, not only can the damping force of the buffer 100 be controlled by adjusting the opening pressure of the valve 1 when power can be supplied to the solenoid (actuator) S under normal circumstances, but a constant thrust is also applied to bias the valve body 4 when power cannot be supplied to the solenoid (actuator) S. Therefore, even without a separate fail valve, the desired damping force can be made to be exerted by the buffer 100 in the event of a fail by setting the thrust. Note that the above advantage can be enjoyed if the actuator can provide a constant thrust to the valve body 4 even when no power is supplied, so the actuator may have a configuration other than the solenoid of this embodiment. Therefore, if the actuator is a push-type solenoid that can push out the movable iron core by a spring when not energized to provide thrust to the valve body 4, the above advantages can be enjoyed. However, in a typical push-type solenoid, in the event of a fail when energization is not possible, the maximum thrust is applied to the valve body 4, causing the pressure in the back pressure chamber 25 to become maximum, the opening pressure of the leaf valve 23 to become maximum, and the damping force of the shock absorber 100 to become excessive. However, with the configuration of the solenoid S of this embodiment, not only is it possible to adjust the opening pressure of the valve 1 by adjusting the amount of current, but the damping force of the shock absorber 100 can also be arbitrarily set in the event of a fail, making it possible to generate the optimal damping force for the vehicle in the shock absorber 100.

[0091] Furthermore, in the valve 1 of this embodiment, the valve seat member 2 has a fitting recess 2d on the inner circumference on the side opposite the seat portion into which the fitting portion 3b is fitted. When the fitting portion 3b is fitted into the fitting recess 2d, the end of the valve seat member 2 on the side opposite the seat portion and the fitting portion 3b become flush. With the valve 1 configured in this way, when the guide member 3 is assembled to the valve seat member 2 and placed on the member to which the valve seat member 2 is assembled (in this embodiment, the bottom portion 24c of the housing 24), the valve seat member 2 and the guide member 3 are stably supported without rattling against each other, so that the valve 1 can operate stably.

[0092] Furthermore, the shock absorber 100 of this embodiment is configured to include a cylinder 101, a piston 102 that is movably inserted into the cylinder 101 and divides the inside of the cylinder 101 into an extension chamber 104 and a compression chamber 105, both of which are filled with hydraulic fluid (liquid), a rod 103 connected to the piston 102, a reservoir 108 for storing hydraulic fluid (liquid), an extension check valve 113 that allows the flow of hydraulic fluid only from the reservoir 108 to the compression chamber 105, a compression check valve 111 that allows the flow of hydraulic fluid only from the compression chamber 105 to the extension chamber 104, a discharge passage 106 that connects the extension chamber 104 and the reservoir 108, and a valve 1 provided in the discharge passage 106 with the extension chamber 104 upstream and the reservoir 108 downstream.

[0093] By configuring the shock absorber 100 as a uniflow type shock absorber in which liquid is always discharged from inside the cylinder 101 to the reservoir 108 through the discharge passage 106 when it expands and contracts, the valve 1 provides resistance to this liquid flow. This allows both the extension damping force and compression damping force of the shock absorber 100 to be adjusted by adjusting the amount of current supplied to the solenoid S. Furthermore, since the valve 1 can be manufactured inexpensively, manufacturing costs can be reduced.

[0094] When valve 1 is applied to a uniflow type buffer 100 in this manner, both the extension damping force and the compression damping force can be adjusted regardless of the direction of extension and contraction of the buffer 100. However, it may also be applied to a biflow type buffer. Biflow type buffers include single-cylinder buffers with an air chamber inside the cylinder and double-cylinder buffers with a reservoir outside the cylinder. In the case of a single-cylinder buffer, the piston is provided with an extension passage that allows liquid to flow from the extension chamber to the compression chamber and a compression passage that allows liquid to flow from the compression chamber to the extension chamber. In the case of a double-cylinder buffer, in addition to these extension and compression passages, it is provided with a suction passage that allows liquid to flow from a reservoir located outside the cylinder to the compression chamber and a discharge passage that allows liquid to flow from the compression chamber to the reservoir. The valve 1, equipped with a solenoid S, can be installed in any of the extension passage, compression passage, or discharge passage. In this manner, the shock absorber equipped with the valve 1 can adjust the damping force generated by changing the amount of current supplied to the solenoid S.

[0095] Furthermore, although the valve 1 in this embodiment is used to control the pressure in the back pressure chamber 25 that biases the leaf valve 23 of the main valve 20, the damping force of the buffer 100 can also be adjusted by controlling the opening pressure of the valve body 4, by eliminating the main valve 20.

[0096] In addition, the main valve 20 is configured to change the damping force in two stages by opening and closing the port 22a of a disc 22 that opens and closes a passage 21e provided in the flange 21b of the valve holding member 21 using a leaf valve 23. However, if it is not necessary to change the damping force in two stages, the disc 22 may be abolished, and the flange 21b of the valve holding member 21 may be used as the disc, with the passage 21e of the flange 21b being opened and closed by the leaf valve 23.

[0097] 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.

[0098] 1... Valve, 2... Valve seat member, 2b... Seat portion, 2c... Annular projection, 2d... Fitting recess, 3... Guide member, 3a... Aligning shaft, 3b... Fitting portion, 3c... Through hole, 4... Valve body, 4a... Insertion hole, 4c... Throttle passage, 5... Disc spring, 6... Support ring, 6a... Notch, 100... Shock absorber, 101... Cylinder, 102... Piston, 103... Rod, 104... Extension chamber, 105... Compression chamber, 106... Discharge passage, 108... Reservoir, 111... Compression check valve, 113... Extension check valve, Pr... Pressure chamber, S... Solenoid (actuator)

Claims

1. A valve comprising: an annular valve seat member having a seat portion on its inner circumference; a guide member having a self-aligning shaft inserted into the valve seat member and being self-aligned with respect to the valve seat member; a valve body slidingly in contact with the outer circumference of the self-aligning shaft and movable in the axial direction relative to the valve seat member and seating away from the seat portion; an annular disc spring interposed between the outer circumference of the valve seat member and the valve body and biasing the valve body in a direction away from the seat portion; and an actuator capable of applying thrust to the valve body in a direction that causes the valve body to seat on the seat portion.

2. A valve according to claim 1, wherein the guide member has a disc-shaped fitting portion having a through hole that penetrates in the axial direction and fits onto the side of the valve seat member opposite the seat portion, and a self-aligning shaft having an outer diameter smaller than the inner diameter of the valve seat member, rising from the fitting portion and being inserted into the inner circumference of the valve seat member.

3. A valve according to claim 1, wherein the valve seat member is annular and has an annular projection on its outer circumference that supports the outer circumference of the disc spring, and comprises a support ring which is laminated on the side of the disc spring opposite the valve seat member and clamps the outer circumference of the disc spring together with the valve seat member, and the support ring has one or more notches on the end opposite the leaf spring.

4. A valve according to claim 1, wherein the valve body has an insertion hole into which the self-aligning shaft is slidably inserted, and a throttling passage that communicates the insertion hole to the outside, and a pressure chamber is partitioned within the insertion hole when the self-aligning shaft is inserted into the insertion hole.

5. A valve according to claim 1, wherein the actuator provides a thrust to the valve body in proportion to the amount of current supplied, and provides a constant thrust to the valve body when de-energized.

6. A valve according to claim 2, wherein the valve seat member has a fitting recess on the inner circumference on the side opposite to the seat portion into which the fitting portion is fitted, and when the fitting portion is fitted into the fitting recess, the end of the valve seat member on the side opposite to the seat portion and the fitting portion become flush.

7. A shock absorber comprising: a cylinder; a piston movably inserted into the cylinder and dividing the cylinder into an extension chamber and a compression chamber filled with liquid; a rod connected to the piston; a reservoir for storing liquid; an extension check valve that allows only the flow of liquid from the reservoir to the compression chamber; a compression check valve that allows only the flow of liquid from the compression chamber to the extension chamber; a discharge passage connecting the extension chamber and the reservoir; and the valve according to claim 1, provided in the discharge passage with the extension chamber upstream and the reservoir downstream.

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