WO2020110452A1

WO2020110452A1 - Damping valve

Info

Publication number: WO2020110452A1
Application number: PCT/JP2019/038506
Authority: WO
Inventors: 瞭汰五味
Original assignee: Ｋｙｂ株式会社
Priority date: 2018-11-26
Filing date: 2019-09-30
Publication date: 2020-06-04
Also published as: JP2020085118A; JP7165032B2

Abstract

A damping valve (V) equipped with: a leaf valve (3) that is provided such that the entirety thereof is movable in an axial direction relative to a piston (10), and that opens/closes a port (10e) formed in the piston (10); a plate (31) provided on the side of the leaf valve (3) away from the piston (10); a plate spring (32) that is arranged separated from the leaf valve (3), and that biases the leaf valve (3) toward the piston (10) via the plate (31); and a damping force adjustment unit provided in series with the leaf valve (3).

Description

Damping valve

The present invention relates to improvement of a damping valve.

▽ Conventionally, damping valves have been used for shock absorbers. Some shock absorbers used for vehicle suspensions include a damping valve capable of automatically adjusting the damping force generated during traveling of the vehicle.

Among such damping valves, for example, as disclosed in JP2010-276111A, a leaf valve provided in the middle of a passage through which liquid passes when the shock absorber expands and contracts, and the leaf valve is provided in the passage. Some have a valve body that is provided in series and that opens and closes a passage, and a damping force adjusting unit that includes a solenoid that can change the valve opening pressure of the valve body according to the amount of energization. According to the damping valve, the damping force generated when the valve opening pressure of the valve body is changed to be low is small, and conversely, when the valve opening pressure of the valve body is changed to be high, it is generated. The damping force increases.

In the damping valve capable of automatically adjusting the damping force as described above, if the mode that minimizes the generated damping force is full soft, there is a demand for the damping valve to reduce the damping force in full soft as much as possible. ..

Then, like the damping valve described in JP2010-276111A, the inner peripheral side (or outer peripheral side) of the leaf valve that is connected in series with the damping force adjusting portion is supported by the valve disc, and the outer peripheral side (or inner peripheral side) is bent. When the passage is opened by reducing the leaf valve rigidity, the damping force at full soft becomes smaller, but there is a limit to reducing the rigidity of the leaf valve, and the damping force at full soft cannot be sufficiently reduced. There are cases.

However, if the leaf valve is lifted so that the entire leaf valve lifts up against the valve disc when the valve is opened, the damping force during full softening can be sufficiently reduced. When the operation direction is changed from extension to contraction or from contraction to extension, there is a possibility that the waveform of the damping force generated due to the delay in closing the leaf valve is disturbed.

Therefore, an object of the present invention is to solve these problems and to provide a damping valve capable of sufficiently reducing the damping force in full soft and preventing the disturbance of the damping force waveform.

A damping valve that solves the above problems is a leaf valve that is provided so as to be movable in the axial direction as a whole with respect to a valve disc and opens and closes a port formed in the valve disc, and a leaf valve on the opposite side of the valve disc A plate provided, a leaf spring which is arranged apart from the leaf valve and urges the leaf valve toward the valve disc through the plate, and a damping force adjusting unit which is provided in series with the leaf valve.

FIG. 1 is a vertical sectional view showing a shock absorber provided with a damping valve according to an embodiment of the present invention. FIG. 2 is an enlarged vertical sectional view of a damping valve according to an embodiment of the present invention. FIG. 3 is a partially enlarged view showing a part of FIG. 2 in an enlarged manner.

Embodiments of the present invention will be described below with reference to the drawings. Like reference symbols in the several drawings indicate like parts.

As shown in FIG. 1, the damping valve V according to the embodiment of the present invention is used for a shock absorber D, and the shock absorber D is used for a vehicle suspension. The shock absorber including the damping valve according to the present invention may be used not only in the vehicle but also in the device other than the shock absorber. Thus, the purpose of use of the damping valve according to the present invention can be changed as appropriate.

The specific structure of the shock absorber D including the damping valve V of the present embodiment will be described below. In the present embodiment, the shock absorber D includes a cylinder 1, a piston 10 slidably inserted into the cylinder 1, a piston having one end connected to the piston 10 and the other end protruding outside the cylinder 1. And a rod 11. The cylinder 1 is connected to one of the vehicle body and the axle of the vehicle, and the piston rod 11 is connected to the other.

In this way, the shock absorber D is interposed between the vehicle body and the axle, and when the wheels move up and down with respect to the vehicle body as the vehicle travels on an uneven road surface, the piston rod 11 causes the cylinder 1 to move. And the shock absorber D expands and contracts, and the piston 10 moves in the cylinder 1 up and down (axial direction) in FIG. Although FIG. 1 shows the piston rod 11 protruding upward from the cylinder 1, the shock absorber D may of course be attached to the vehicle in any orientation.

Next, an annular head member 12 that allows the piston rod 11 to be inserted is attached to one end of the cylinder 1 in the axial direction. The head member 12 slidably supports the piston rod 11 and closes one end of the cylinder 1. On the other hand, the other end of the cylinder 1 is closed by a bottom cap 13. In this way, the inside of the cylinder 1 is hermetically sealed, and gas and liquid are enclosed in the cylinder 1.

More specifically, a free piston 14 is slidably inserted into the cylinder 1 on the side opposite to the piston rod 11 when viewed from the piston 10, and a liquid such as hydraulic oil is provided on the piston 10 side from the free piston 14. A liquid chamber L filled with is formed. On the other hand, a gas chamber G in which a compressed gas such as air or nitrogen gas is enclosed is formed on the side opposite to the piston 10 in the cylinder 1 when viewed from the free piston 14.

As described above, the liquid chamber L and the gas chamber G in the cylinder 1 are partitioned by the free piston 14. When the piston rod 11 moves in and out of the cylinder 1 when the shock absorber D expands and contracts, the free piston 14 moves up and down (axial direction) in FIG. 1 to expand and contract the gas chamber G to move in and out of the cylinder 1. To compensate for the volume of the piston rod 11.

However, the configuration of the shock absorber D is not limited to that shown in the drawing, and can be changed as appropriate. For example, it is assumed that a reservoir for containing a liquid and a gas is provided in place of the gas chamber G, and liquid is exchanged between the cylinder and the reservoir when the shock absorber expands and contracts to compensate for the piston rod volume entering and leaving the cylinder. Good. Further, the shock absorber may be a double rod type, and the piston rods may be provided on both sides of the piston, and in this case, the structure itself for compensating the piston rod volume can be omitted.

Subsequently, the liquid chamber L in the cylinder 1 is partitioned by the piston 10 into an expansion side chamber L1 on the piston rod 11 side and a compression side chamber L2 on the opposite side (opposite rod side). The damping valve V according to the present embodiment is embodied in the piston 10 portion.

As shown in FIG. 2, the damping valve V includes a piston 10, a leaf valve assembly R including the expansion-side and compression-

side leaf valves

2 and 3 stacked on the piston 10, and the leaf valve assembly R. And a damping force adjusting portion A which is provided at a connecting portion between the piston rod 11 and the

leaf valve

2 and 3 on the extension side and the compression side in series. Hereinafter, each of these members that constitute the damping valve V will be described in detail. In the following description, for convenience of description, FIG. 2 and FIG. The middle and upper parts are simply called "upper" and "lower".

As shown in FIG. 2, the piston 10 has a bottomed tubular shape, and has a cylindrical portion 10b on the outer periphery of which a piston ring 10a slidably contacting the inner periphery of the cylinder 1 is mounted, and a bottom portion 10c that closes the lower end of the cylindrical portion 10b. including. A case 4 to be described later of the damping force adjusting portion A is screwed into the tubular portion 10b, and an intermediate chamber L3 is formed between the bottom portion 10c and the damping force adjusting portion A. The piston 10 separates the intermediate chamber L3 from the pressure side chamber L2 formed below the piston 10.

Further, the bottom 10c of the piston 10 is formed with

ports

10d and 10e on the extension side and the compression side, which communicate the intermediate chamber L3 and the compression side chamber L2. Furthermore, an expansion-side leaf valve 2 that opens and closes the expansion-side port 10d is stacked below the bottom 10c, and a compression-side leaf valve 3 that opens and closes the compression-side port 10e is stacked above the bottom 10c. In this way, the piston 10 functions as a valve disc in which a port that connects the two chambers is formed and a leaf valve that opens and closes the port is mounted.

The extension side port 10d is always in communication with the intermediate chamber L3, and the pressure of this intermediate chamber L3 acts in the direction of opening the extension side leaf valve 2. When the expansion side leaf valve 2 is opened under the pressure of the intermediate chamber L3, the liquid flows from the intermediate chamber L3 to the compression side chamber L2 through the expansion side port 10d. On the other hand, the pressure side port 10e is always communicated with the pressure side chamber L2, and the pressure of the pressure side chamber L2 acts in the direction of opening the pressure side leaf valve 3. When the pressure-side leaf valve 3 is opened under the pressure of the pressure-side chamber L2, the liquid flows from the pressure-side chamber L2 to the intermediate chamber L3 through the pressure-side port 10d.

Next, the damping force adjusting portion A is tubular and has a case 4 whose upper end is screwed into a cylindrical portion 11a provided at the tip of the piston rod 11 and whose lower end is screwed into a cylindrical portion 10b of the piston 10. An annular valve seat member 5 fixed by being sandwiched between the lower end of the case 4 and the piston 10, and a first valve body 6 in which a tip portion 6a is slidably inserted inside the valve seat member 5. And the second valve body 7 slidably inserted into the case 4 above the first valve body 6 and the valve opening pressures of the first and

second valve bodies

6 and 7 can be changed. And an appropriate valve opening pressure adjusting unit P.

The first valve body 6 is annular and has a tip portion 6a slidably inserted into the valve seat member 5 and an outer diameter that is continuous with the upper side of the tip portion 6a and gradually increases as the outer diameter increases. It includes a truncated cone-shaped taper portion 6b that expands in diameter and a valve seat portion 6c that is continuous with the upper end of the taper portion 6b. Then, the first valve body 6 moves up and down while the tip portion 6 a is supported by the valve seat member 5, and the taper portion 6 b is separated from the annular first valve seat 5 a formed on the valve seat member 5. Sit down. Further, a notch is provided on the outer circumference of the tip portion 6a so that when the first valve body 6 separates from the first valve seat 5a, the inner circumference side and the outer circumference side can communicate with each other. ..

On the other hand, the second valve body 7 includes a small diameter portion 7a located at the upper end, a large diameter portion 7b connected to the lower side of the small diameter portion 7a and having an outer diameter larger than the outer diameter of the small diameter portion 7a, and this large diameter portion 7a. A leg portion 7c that is connected to the lower side of 7b and has an outer diameter smaller than the outer diameter of the large diameter portion 7b is included. Then, the second valve body 7 moves up and down while slidingly contacting the small diameter portion 7a and the large diameter portion 7b with the inner circumference of the case 4, and the upper end of the valve seat portion 6c of the first valve body 6 is moved. The second valve seat 6d, which is an annular member, is seated on and off.

A case 4 surrounds the outer circumferences of the tapered portion 6b and the valve seat portion 6c of the first valve body 6 protruding upward from the valve seat member 5 and the outer circumference of the leg portion 7c of the second valve body 7. An annular gap 4a is formed. Further, the case 4 is formed with a through hole 4b which communicates the gap 4a with the expansion side chamber L1, and the pressure of the expansion side chamber L1 is passed through the through hole 4b and the gap 4a to form the first and second valve bodies. Acts on 6,7.

More specifically, the area of a circle whose diameter is the outer diameter of the maximum outer diameter portion of the first valve body 6 protruding upward from the valve seat member 5 is c1, and the outer diameter of the first valve seat 5a is the diameter. When the area of the circle is c2, c1 is larger than c2 (c1>c2), and the first valve body 6 is biased upward by the pressure in the extension side chamber L1. If the area of a circle having the outer diameter of the large diameter portion 7b of the second valve body 7 as its diameter is c3 and the area of the circle having the outer diameter of the second valve seat 6d as c4, c3 is c4. It is larger (c3>c4), and the second valve body 7 is also urged upward by the pressure of the extension side chamber L1. Then, when the first and

second valve bodies

6 and 7 receive the pressure of the expansion side chamber L1 and move upward, the first valve body 6 separates from the first valve seat 5a, and the liquid flows between them. It goes from the extension side chamber L1 to the intermediate chamber L3.

Further, the intermediate chamber L3 is communicated with the upper clearance 4c formed on the upper side of the small diameter portion 7a of the second valve body 7 by the communication hole 7d penetrating the second valve body 7 in the axial direction. As a result, the pressure in the upper clearance 4c becomes substantially the same as the pressure in the intermediate chamber L3. Further, the intermediate chamber L3 is between the second valve body 7 and the bottom portion 10c of the piston 10, and is surrounded by the first valve body 6, the valve seat member 5, and the cylinder portion 10b of the piston 10. The pressure in the intermediate chamber L3 acts on the first and

second valve bodies

6 and 7.

More specifically, in the first valve body 6, the area of a circle whose diameter is the inner diameter of the second valve seat 6d is c5, and the area of a circle whose diameter is the inner diameter of the smallest inner diameter portion of the first valve body 6 is c6, where c7 is the area of a circle whose diameter is the inner diameter of the first valve seat 5a, the area obtained by subtracting c6 from c5 is larger than the area obtained by subtracting c6 from c7 (c5-c6>c7-c6), The first valve body 6 is biased downward by the pressure of the intermediate chamber L3. Further, when the area of a circle whose diameter is the outer diameter of the small diameter portion 7a of the second valve body 7 is c8, the above c5 (the area of a circle whose diameter is the inner diameter of the second valve seat 6d) is greater than c8. Large (c5>c8), the second valve body 7 is biased upward by the pressure of the intermediate chamber L3.

In this way, the first and

second valve bodies

6 and 7 are urged in the upward and downward directions by the pressure of the intermediate chamber L3. Then, when the first and

second valve bodies

6 and 7 are divided into upper and lower parts by receiving the pressure of the intermediate chamber L3, the second valve body 7 separates from the second valve seat 6d, and the liquid flows between them. It goes from the intermediate chamber L3 to the extension side chamber L1. On the other hand, the first valve body 6 is urged downward by the pressure of the intermediate chamber L3, that is, in the direction of sitting on the first valve seat 5a (closing direction), so that the pressure of the intermediate chamber L3 increases. But it doesn't open.

In summary, the pressure in the extension side chamber L1 acts in the direction (opening direction) in which the first valve body 6 is separated from the first valve seat 5a. On the other hand, the pressure in the intermediate chamber L3 acts in the direction (opening direction) in which the second valve body 7 is separated from the second valve seat 6d. Then, when the first valve body 6 or the second valve body 7 is opened under the pressure of the expansion side chamber L1 or the intermediate chamber L3, the expansion side chamber L1 and the intermediate chamber L3 are separated from each other through the through hole 4b and the gap 4a. Communicated. As described above, the expansion side port 10d opened and closed by the expansion side leaf valve 2 and the compression side port 10e opened and closed by the compression side leaf valve 3 are connected to the intermediate chamber L3.

That is, in the present embodiment, the passage 4b, the gap 4a, the intermediate chamber L3, and the passage F that connects the expansion side chamber L1 and the compression side chamber L2 are configured by the expansion side and

compression side ports

10d and 10e. In addition, in this passage F,

leaf valves

2 and 3 on the expansion side and the pressure side are provided in parallel, and first and

second valve bodies

6 and 7 are provided in series with these

leaf valves

2 and 3. Then, the valve opening pressures of the first and

second valve bodies

6 and 7 can be changed by the valve opening pressure adjusting section P.

In the present embodiment, the valve opening pressure adjusting section P reduces the pressure of the back pressure chamber L4 formed on the upper side of the large diameter portion 7b of the second valve body 7 and the extension side chamber L1 to reduce the back pressure chamber. A pressure introducing passage p1 leading to L4, a pressure control passage p2 communicating the back pressure chamber L4 and the intermediate chamber L3 through the upper gap 4c and the communication hole 7d, and a spool 8 opening and closing the pressure control passage p2. A solenoid (not shown) that applies thrust to the spool 8 and a decompression passage that allows only the flow of liquid from the intermediate chamber L3 toward the back pressure chamber L4 and reduces the pressure in the intermediate chamber L3 and guides it to the back pressure chamber L4. p3 and.

The spool 8 is slidably mounted in the accommodation hole 7e formed in the second valve body 7, and is biased upward by the pressure of the back pressure chamber L4. A downward thrust is applied to the spool 8 by a solenoid. As a result, when the pressure in the back pressure chamber L4 increases and the upward force due to the pressure or the like overcomes the downward force due to the solenoid or the like, the spool 8 moves upward and separates from the valve seat 7f. , The pressure control passage p2 is opened.

A harness H (FIG. 1) for energizing is connected to the solenoid, and the harness H extends through the inside of the piston rod 11 to the outside of the shock absorber D. The thrust of the solenoid is increased or decreased by changing the energization amount, and the valve opening pressure of the spool 8 increases as the thrust of the solenoid increases. Since the pressure of the back pressure chamber L4 is set to the valve opening pressure of the spool 8, it can be said that the solenoid and the spool 8 constitute a pressure control valve that controls the pressure of the back pressure chamber L4.

The second valve body 7 is urged downward by the pressure of the back pressure chamber L4, that is, in the direction of seating on the second valve seat 6d (closing direction). Further, when the spool 8 is seated on the valve seat 7f, the thrust of the solenoid acts in the direction of pushing down the second valve body 7 via the spool 8. That is, when the spool 8 is seated on the valve seat 7f, the second valve body 7 is also urged downward (closed) by the solenoid itself. Then, when the second valve body 7 is seated on the second valve seat 6d, the first valve body 6 also receives the downward (closing direction) biasing force.

According to the above configuration, when the shock absorber D extends, the piston 10 moves upward in the cylinder 1 to compress the expansion side chamber L1, and when the pressure in the expansion side chamber L1 rises, the liquid in the expansion side chamber L1 causes the liquid to flow into the pressure introduction passage p1. Through the back pressure chamber L4 to increase the pressure in the back pressure chamber L4. Then, when the pressure in the back pressure chamber L4 reaches the valve opening pressure of the spool 8 set according to the energization amount of the solenoid, the spool 8 opens, and the liquid in the back pressure chamber L4 receives the pressure control passage p2 and the upper clearance 4c. , And through the communication hole 7d toward the intermediate chamber L3. Therefore, when the shock absorber D extends, the pressure in the back pressure chamber L4 is controlled.

Further, when the upward force due to the pressure of the extension side chamber L1 acting on the first and

second valve bodies

6 and 7 when the shock absorber D extends becomes larger than the downward force due to the pressure of the back pressure chamber L4, The first and

second valve bodies

6 and 7 move upward to open the first valve body 6. Then, the liquid in the expansion side chamber L1 moves to the intermediate chamber L3 through the gap formed between the first valve body 6 and the first valve seat 5a, and the liquid in the intermediate chamber L3 moves toward the expansion side leaf valve 2 Open and move to the pressure side chamber L2.

As described above, resistance is imparted to the flow of the liquid from the expansion side chamber L1 to the compression side chamber L2 by the first valve body 6 and the expansion side leaf valve 2. Therefore, when the shock absorber D extends, the pressure in the expansion side chamber L1 rises, and the shock absorber D exerts an expansion side damping force that prevents the expansion operation. Further, as the valve opening pressure of the spool 8 is increased by changing the energization amount to the solenoid, the pressure in the back pressure chamber L4 is increased and the force for urging the first valve body 6 downward is increased. Then, the valve opening pressure of the first valve body 6 becomes high, and the extension side damping force generated becomes large.

On the contrary, when the shock absorber D contracts, the piston 10 moves downward in the cylinder 1 to compress the pressure side chamber L2, and when the pressure in the pressure side chamber L2 rises, the liquid in the pressure side chamber L2 opens the leaf valve 3 on the pressure side. While moving to the intermediate chamber L3, the liquid in the intermediate chamber L3 moves to the back pressure chamber L4 through the pressure reducing passage p3. At this time, the pressure of the upper clearance 4c located on the downstream side of the spool 8 is substantially the same as the pressure of the intermediate chamber L3, and is higher than the pressure of the back pressure chamber L4 located on the upstream side of the spool 8. Therefore, the spool 8 is maintained in the closed state, and the thrust of the solenoid acts on the second valve body 7 via the spool 8.

Further, as described above, since the pressure in the intermediate chamber L3 acts upward only on the second valve body 7, the upward force due to the pressure in the intermediate chamber L3 acting on the second valve body 7 or the like. When exceeds the downward force due to the thrust force of the solenoid, only the second valve body 7 moves upward and opens. Then, the liquid in the intermediate chamber L3 moves to the extension side chamber L1 through the gap formed between the second valve body 7 and the second valve seat 6d.

In this way, resistance is imparted to the flow of liquid from the pressure side chamber L2 toward the expansion side chamber L1 by the pressure side leaf valve 3 and the second valve body 7. Therefore, when the shock absorber D contracts, the pressure in the pressure side chamber L2 increases, and the shock absorber D exerts a damping force on the pressure side that prevents the contraction operation. Further, the larger the thrust of the solenoid is changed by changing the energization amount, the larger the force that urges the second valve body 7 downward. Then, the valve opening pressure of the second valve body 7 increases, and the generated damping force on the pressure side increases.

That is, the damping force adjusting unit A in the present embodiment can change the valve opening pressures of the first and

second valve bodies

6 and 7 that are connected in series with the extension side and pressure

side leaf valves

2 and 3. The valve opening pressure adjusting part P is provided. Then, the valve opening pressure adjusting unit P changes the valve opening pressure of the first valve body 6 by controlling the pressure of the back pressure chamber L4, and changes the valve opening pressure of the second valve body 7. The thrust force of the solenoid used to control the pressure of the back pressure chamber L4 is directly applied to the second valve body 7, and the thrust force is adjusted.

Further, in the present embodiment, the leaf valve assembly R is configured to include the expansion side leaf valve 2, the compression side leaf valve 3, and the piston 10 that is a valve disc, and the damping force adjusting portion A thereof is It can be said that the leaf valve assembly R is connected in series. The configuration of the damping force adjusting unit A can be appropriately changed as long as it is provided in series with the leaf valve assembly R and the magnitude of the damping force generated can be adjusted.

Next, the expansion side leaf valve 2 is a thin annular plate having elasticity and one or more are laminated below the bottom portion 10c of the piston 10. The leaf valve 2 on the extension side is fixed to the bottom portion 10c of the piston 10 on the inner peripheral side in a state where the outer peripheral side thereof is allowed to flex.

More specifically, a mounting hole (not shown) is formed in each of the bottom portion 10c of the piston 10 and the center portion of the extension-side leaf valve 2 stacked on the bottom portion 10c, and the mounting shaft 15 is provided in the mounting hole. It has been inserted. A flange portion 15a having an outer diameter larger than that of the other portion is provided at one end of the mounting shaft 15, and a screw portion 15b with which a nut 16 is screwed is provided at the other end of the mounting shaft 15. ing.

Then, the bottom portion 10c of the piston 10 and the inner peripheral portion of the extension side leaf valve 2 are sandwiched and fixed between the flange portion 15a and the nut 16. Further, at the lower end of the bottom portion 10c facing the extension side leaf valve 2, an extension side valve seat 10f is formed so as to surround the outlet of the extension side port 10d, and the outer circumference of the extension side leaf valve 2 is formed. The part is seated on and off the valve seat 10f on the extension side. As a result, the outlet of the expansion side port 10d is opened and closed.

On the other hand, the inlet of the port 10d on the extension side is always open and is in communication with the intermediate chamber L3. When the pressure in the intermediate chamber L3 increases when the shock absorber D extends, the outer peripheral portion of the expansion-side leaf valve 2 receives the pressure and bends downward, away from the expansion-side valve seat 10f and expanded-side port 10d. open. However, when the operating direction of the shock absorber D switches from extension to contraction and the pressure in the intermediate chamber L3 decreases, the leaf valve 2 on the extension side has its own outer periphery seated on the valve seat 10f on the extension side. , The port 10d on the extension side is returned to the closed state.

Next, the pressure side leaf valve 3 is a thin annular plate having elasticity, and one or more sheets are laminated on the upper side of the bottom portion 10c of the piston 10. The leaf valve 3 on the pressure side is attached to the piston 10 so that the entire leaf valve 3 can move in the axial direction with respect to the piston 10. That is, in the present embodiment, the pressure side leaf valve 3 is of the lift type.

More specifically, as shown in FIG. 3, a guide 30 is provided on the outer periphery of the mounting shaft 15 and above the bottom portion 10c, and the guide 30 is sandwiched between the flange portion 15a and the nut 16 together with the piston 10 and the like. It is fixed. Further, the guide 30 is composed of a plurality of washers 30a that overlap in the axial direction, and the axial length of the guide 30 as a whole is longer than the axial length of the pressure side leaf valve 3 as a whole.

The pressure side leaf valve 3 is slidably contacted with the outer circumference of the guide 30, and the entire inner circumference is movable in the axial direction with respect to the piston 10 while being supported by the guide 30. Furthermore, a pressure side valve seat 10g is formed at the upper end of the bottom portion 10c facing the pressure side leaf valve 3 so as to surround the outlet of the pressure side port 10e, and the outer peripheral portion of the pressure side leaf valve 3 is formed by the valve seat 10g. The valve seat 10g on the pressure side is separated and seated. As a result, the outlet of the pressure side port 10e is opened and closed.

Further, in the present embodiment, two pressure side leaf valves 3 are provided, and the plate 31 is welded to the upper end outer peripheral portion of the upper side leaf valve 3 of the two pressure side leaf valves 3. .. On the other hand, the lower leaf valve 3 to which the plate 31 is not welded contacts the pressure side valve seat 10g. Here, when the leaf valve distorted due to welding is brought into contact with the valve seat when the valve is closed, the strain causes an unnecessary gap between the leaf valve and the valve seat. Generation of such a gap is prevented.

The plate 31 is annular and has a width slightly larger than the width of the pressure side valve seat 10g, and faces the pressure side valve seat 10g with the pressure side leaf valve 3 interposed therebetween. The plate spring 32 is in contact with the upper end of the plate 31. The leaf spring 32 is formed of an elastic annular plate, and the inner peripheral portion of the leaf spring 32 is laminated on the guide 30 and is fixed by being sandwiched between the flange portion 15a and the nut 16 together with the piston 10 and the like. On the other hand, the outer peripheral side of the leaf spring 32 is allowed to bend, and the outer peripheral portion of the leaf spring 32 overlaps the upper side of the plate 31.

Furthermore, a stopper 33 is provided above the leaf spring 32. Then, when the outer peripheral portion of the leaf spring 32 bends upward and the amount of deflection (deformation amount) increases to some extent, the leaf spring 32 contacts the stopper 33 and further bending is prevented. That is, the stopper 33 limits the amount of deformation of the leaf spring 32 in the direction away from the piston 10.

Further, in the state where the pressure side leaf valve 3 is seated on the pressure side valve seat 10g, the leaf spring 32 is deformed so that the outer peripheral side thereof is slightly higher than the inner peripheral side. Therefore, the compression-side leaf valve 3 is always urged downward by the elastic force of the leaf spring 32, that is, in the direction in which it is seated on the compression-side valve seat 10g (closing direction).

The inlet of the pressure side port 10e whose outlet is opened and closed by the pressure side leaf valve 3 is always open and is in communication with the pressure side chamber L2. Then, when the pressure in the pressure side chamber L2 increases when the shock absorber D contracts, the entire pressure side leaf valve 3 is lifted upward against the biasing force of the leaf spring 32, away from the pressure side valve seat 10g, and the pressure side port 10e. open. However, when the operating direction of the shock absorber D switches from contraction to extension and the pressure in the pressure side chamber L2 decreases, the pressure side leaf valve 3 is pushed down by the biasing force of the leaf spring 32 and seated on the pressure side valve seat 10g. , Return to the state in which the pressure side port 10e is closed.

Further, when the leaf valve 3 on the pressure side is opened, if the amount of upward deflection of the outer peripheral portion of the leaf spring 32 becomes large to some extent, it comes into contact with the stopper 33. As a result, further deformation (deflection) of the leaf spring 32 is prevented, and upward movement of the pressure side leaf valve 3 is also prevented. As described above, in the present embodiment, the stopper 33 limits the amount of deformation of the leaf spring 32, thereby limiting the amount of opening of the pressure side leaf valve 3.

A gap S is formed between the leaf valve 3 on the pressure side and the leaf spring 32 while the leaf valve 3 on the pressure side is seated on the valve seat 10g on the pressure side. The gap S is communicated with the intermediate chamber L3 by a hole 32a formed in the leaf spring 32 so as to penetrate through the thickness thereof. As a result, a pressure difference is generated between the gap S and the intermediate chamber L3, and the leaf spring 32 can be prevented from being cracked by the pressure difference.

As described above, in the present embodiment, the leaf valve assembly R that constitutes the damping valve V has the expansion-side and compression-

side leaf valves

2 and 3, and the piston 10 that is a valve disc. 3 is a lift type. Further, the leaf valve assembly R has a plate 31, a leaf spring 32, and a stopper 33, and biases the lift-side pressure-side leaf valve 3 in the closing direction and limits the opening amount thereof. It is supposed to do.

The operation and effect of the damping valve V according to this embodiment will be described below.

In the present embodiment, the damping valve V includes a piston (valve disk) 10 in which a pressure side port (port) 10e is formed, and a whole of the piston 10 that is axially movable so as to move in the pressure side port. The pressure side leaf valve (leaf valve) 3 for opening and closing 10e, the plate 31 provided on the side opposite to the piston 10 of the pressure side leaf valve 3, and the plate 31 provided apart from the pressure side leaf valve 3. A leaf spring 32 that urges the leaf valve 3 on the pressure side toward the piston 10 via a damping force adjusting portion A provided in series with the leaf valve 3 on the pressure side.

The axial direction in which the pressure side leaf valve 3 can move is the plate thickness direction of the pressure side leaf valve 3, and according to the above configuration, the entire pressure side leaf valve 3 is separated from the piston 10. In this way, when the pressure-side leaf valve 3 is of the lift type, it can be opened easily without significantly lowering the valve rigidity of the pressure-side leaf valve 3 itself. Therefore, in order to reduce the damping force on the pressure side in the full soft mode in which the damping force generated by the adjustment of the damping force adjusting unit A is set to the minimum, it is not necessary to reduce the valve rigidity of the leaf valve 3 on the pressure side so much, and It is possible to sufficiently reduce the damping force on the compression side during full softening while ensuring the valve rigidity of the leaf valve 3.

The damping valve V also includes a leaf spring 32 that urges the pressure-side leaf valve 3 toward the piston 10, that is, in the closing direction. Therefore, when the operation direction of the shock absorber D is switched from contraction to extension, the leaf valve 3 on the pressure side receives the biasing force of the leaf spring 32 and moves to the piston 10 side, and the port 10e on the pressure side is opened. It will be closed promptly. That is, according to the above configuration, even if the pressure-side leaf valve 3 is of the lift type, it is possible to prevent the closing delay, so that the closing delay is caused while sufficiently reducing the compression-side damping force during full softening. It is possible to prevent the disturbance of the damping force waveform.

Further, in the present embodiment, the leaf spring 32 is arranged apart from the pressure-side leaf valve 3 and biases the pressure-side leaf valve 3 via the plate 31. Therefore, the initial deflection of the leaf spring 32 can be adjusted by balancing the heights of the plate 31 and the portion that supports the leaf spring 32 (the guide 30 in the present embodiment). Further, the leaf spring 32 may be a flat plate-shaped member such as an annular plate and is not bulky in the axial direction. With this configuration, the leaf spring 32 does not push up other members significantly before the nut 16 is tightened in the process of assembling the leaf valve assembly R, so that the leaf valve assembly R can be easily assembled. As a result, the assembling property of the damping valve V can be improved.

Further, in the present embodiment, a plurality of pressure side leaf valves 3 are provided, and the plate 31 is welded to the pressure side leaf valve 3 which is located farthest from the piston 10. By fixing the plate 31 to the pressure-side leaf valve 3 in this manner, it is possible to prevent the plate 31 from being displaced from the position where the biasing force of the leaf spring 32 is to be applied in the pressure-side leaf valve 3. Therefore, the biasing force of the leaf spring 32 can be applied to the predetermined position of the leaf valve 3 on the pressure side.

Further, according to the above configuration, the pressure side leaf valve 3 other than the welded pressure side leaf valve 3 of the plate 31 contacts the pressure side valve seat 10g of the piston 10 when the valve is closed. As described above, according to the above configuration, it is possible to bring the pressure-side leaf valve 3 without distortion due to welding into contact with the pressure-side valve seat 10g. Therefore, when the valve is closed, it is possible to prevent an unnecessary gap from being formed between the pressure side leaf valve 3 and the pressure side valve seat 10g due to distortion due to welding, and it is possible to prevent the generated damping force from varying.

Further, in the present embodiment, the plate 31 is formed in an annular shape, and is provided at a position overlapping the pressure side valve seat 10g in the axial direction. The position where the valve seat overlaps with the valve seat in the axial direction is a position facing the valve seat with the leaf valve interposed therebetween. The biasing force of the spring 32 is applied. As a result, the pressure side leaf valve 3 can be reliably seated on the pressure side valve seat 10g. However, the position, shape, and joining method of the plate 31 can be changed as appropriate.

Further, in the present embodiment, the leaf spring 32 is formed with a hole 32a penetrating its thickness. Therefore, it is possible to prevent a differential pressure from occurring on both sides of the leaf spring 32 in the plate thickness direction, and to prevent the leaf spring 32 from cracking due to the differential pressure. Furthermore, the spring constant of the leaf spring 32 can be tuned according to the size and shape of the hole 32a. However, the hole 32a may be eliminated, and a gap may be formed between the plate 31 and the plate spring 32 by a notch or the like to prevent a differential pressure from occurring on both sides of the plate spring 32 in the plate thickness direction.

Further, the shape of the leaf spring 32 is not limited to a ring shape, and can be changed as appropriate. For example, the leaf spring may have an annular fixing portion fixed to the outer periphery of the mounting shaft 15 together with the piston 10 and the like, and a plurality of leg portions radially protruding outward from the fixing portion. Even in such a case, it is possible to prevent a pressure difference from occurring on both sides of the plate spring in the plate thickness direction, and it is possible to tune the spring constant of the plate spring according to the number and width of the leg portions.

Further, in the present embodiment, the pressure side leaf valve 3 is annular, and one or more sheets are laminated on the piston (valve disc) 10, and the axial length is greater than the axial length of the entire pressure side leaf valve 3. It is mounted on the outer circumference of the long guide 30 so as to be slidable. The axial length of the entire pressure-side leaf valve 3 corresponds to the plate thickness of one pressure-side leaf valve 3 laminated on the piston 10, and is laminated on the piston 10. When there are a plurality of pressure-side leaf valves 3 corresponding to each pressure side, this corresponds to the total thickness of the leaf valves 3 on each pressure side.

According to the above configuration, the pressure side leaf valve 3 can be smoothly moved in the axial direction with respect to the piston 10 while being supported by the guide 30. Therefore, it is possible to more reliably prevent the closing delay of the leaf valve 3 on the pressure side. Furthermore, in the present embodiment, the guide 30 is configured to have a plurality of stacked washers 30a, so that the axial length (height) of the guide 30 can be easily adjusted.

However, the guide 30 may be composed of one tubular member. Further, in the present embodiment, the pressure side leaf valve 3 is mounted on the outer circumference of the guide 30, and the outer peripheral portion of the pressure side leaf valve 3 is seated on and seated on the pressure side valve seat 10g of the piston 10, and thereby the pressure side The port 10e is opened and closed. However, a guide may be provided on the outer circumference of the pressure-side leaf valve 3, and the inner peripheral portion of the pressure-side leaf valve 3 may be seated on or off the pressure-side valve seat.

Further, the damping valve V of the present embodiment is provided with a stopper 33 that limits the amount of deformation of the leaf spring 32. With this configuration, the stopper 33 can prevent the leaf spring 32 from being deformed by a predetermined amount or more. When the leaf spring 32 is prevented from being deformed, the pressure-side leaf valve 3 cannot be opened anymore. Therefore, according to the above configuration, the opening amount of the pressure-side leaf valve 3 can be limited.

Further, in the present embodiment, the damping force adjusting unit A is located at the downstream side of the pressure side leaf valve 3, and the valve opening pressure adjustment for adjusting the valve opening pressure of the second valve body 7. And a part P. In this way, when the valve element is located on the downstream side of the leaf valve, the back pressure of the leaf valve is less likely to increase when the operating direction of the shock absorber is switched, and the problem of delay in closing the leaf valve is likely to occur. Therefore, according to the above configuration, it is particularly effective to bias the leaf valve 3 on the pressure side toward the piston 10 side by the leaf spring 32.

However, the extension side leaf valve 2 may be of a lift type and a plate may be provided on the side opposite to the piston 10, and the extension side leaf valve 2 may be biased toward the piston 10 side by a leaf spring via this plate. ..

Further, in the present embodiment, the damping valve according to the present invention is embodied in the piston 10 portion of the shock absorber D. However, the position where the damping valve according to the present invention is provided can be appropriately changed. For example, when the shock absorber is a uniflow type and the liquid circulates in one direction in the order of the expansion side chamber, the reservoir, and the pressure side chamber during expansion and contraction, the damping valve according to the present invention is provided in the middle of the circulation passage. Good. In such a case, the leaf valve does not have to be divided into the expansion side and the compression side.

The preferred embodiments of the present invention have been described above in detail, but modifications, variations, and changes can be made without departing from the scope of the claims.

This application claims priority based on Japanese Patent Application No. 2018-219898 filed with the Japan Patent Office on November 26, 2018, the entire contents of which are incorporated herein by reference.

Claims

A damping valve,
A valve disc in which a port is formed,
A leaf valve which is provided so as to be movable in the axial direction as a whole with respect to the valve disc and opens and closes the port,
A plate provided on the opposite side of the leaf valve from the valve disc;
A leaf spring disposed apart from the leaf valve and biasing the leaf valve toward the valve disc through the plate;
A damping valve, comprising: a damping force adjusting unit provided in series with the leaf valve.
The damping valve according to claim 1, wherein
The leaf valve has an annular shape, and one or more sheets are laminated on the valve disc. The leaf valve is slidably attached to the outer circumference of a guide having an axial length longer than the axial length of the entire leaf valve. Damping valve.
The damping valve according to claim 1, wherein
A damping valve comprising a stopper that limits the amount of deformation of the leaf spring.