WO2016195008A1

WO2016195008A1 - Damping valve and shock absorber

Info

Publication number: WO2016195008A1
Application number: PCT/JP2016/066384
Authority: WO
Inventors: 大輔石井
Original assignee: Ｋｙｂ株式会社
Priority date: 2015-06-03
Filing date: 2016-06-02
Publication date: 2016-12-08
Also published as: CN107614923A; JP6464036B2; JP2016223597A

Abstract

[Problem] To provide a damping valve that can reliably block the flow channel at a desired pressure and a shock absorber. [Solution] A damping valve comprises: a piston (10) that has a valve hole (H) by which an extension side chamber (L1) and a compression side chamber (L2) communicate; a valve body (6) that has a sliding shaft (60a) inserted into the valve hole (H) so as to be able to slide; a step (10e) that regulates motion of the valve body (6) toward the compression side chamber (L2); a coil spring (8) that biases the valve body (6) toward the compression side chamber (L2); and a flow channel (62), one end of which opens to the side of the sliding shaft (60a) and the other end of which opens further toward the extension side chamber (L1) side than the sliding shaft (60a) of the valve body (6). The flow channel (62) is blocked when the valve body (6) moves to the extension side chamber (L1) side and the one end opening (o1) of the flow channel (62) faces the wall face of the valve hole H that is in sliding contact with the outer circumference of the sliding shaft (60a).

Description

Damping valve and shock absorber

This invention relates to a damping valve and a shock absorber.

Conventionally, a damping valve is used, for example, as a shock absorber that is interposed between a bogie and a vehicle body of a railway vehicle to suppress vehicle body vibration. In such a damping valve, as disclosed in JP5324502B, one of two chambers formed in the shock absorber is upstream and the other is downstream. An annular valve seat provided in the middle of the valve hole, a valve body movably accommodated in the valve hole and seated on and away from the annular valve seat, a spring seat fixed in the valve hole, a valve body and a spring seat, And a first port that is provided between the annular valve seat and the annular valve seat, and communicates the space between the annular valve seat and the spring seat to the other chamber. And a second port that bypasses the first port and communicates the space to the other chamber, and a damping valve that shuts off the first port when the valve body is retracted by a predetermined amount in a direction away from the annular valve seat. is there. According to such a damping valve, the pressure flow characteristic when the first port is closed and the pressure flow characteristic when the first port is open can be set independently and freely.

Here, in the damping valve disclosed in JP5324502B, when the lift amount of the valve body gradually increases and reaches a predetermined lift amount, the valve body hits the spring seat and closes the first port. Yes. The spring seat is screwed into the valve hole. When the spring seat is rotated and moved in the direction of the rotation axis, the preset load of the spring can be changed.

However, when the preset load of the spring is adjusted as described above, the distance from the valve body to the spring seat varies depending on the product, and thus the lift amount of the valve body required to close the first port varies. Further, as described above, the spring seat is screwed into the valve hole, and it is difficult to make the surface of the spring seat on the valve body side perpendicular to the axis of the valve body. In addition, there is an influence of the fluid force of the fluid passing through the first port. Therefore, not only in the case shown in FIG. 1 disclosed in JP5324502B, but also in the case where the end of the valve body has a truncated cone shape as shown in FIG. 4, the pressure in one chamber becomes a desired pressure. If this happens, the first port may not be securely blocked.

Therefore, an object of the present invention is to provide a damping valve and a shock absorber that can solve the above problems and can reliably block the flow path with a desired pressure.

In order to solve the above-described problems, the present invention includes a valve body having a sliding shaft portion into which a damping valve is slidably inserted into a valve hole, and a flow path provided in the valve body. When the opening on one end side of the passage is opposed to the wall surface of the valve hole that is in sliding contact with the outer periphery of the sliding shaft portion, the passage is closed.

It is the figure which showed in principle the shock absorber carrying the damping valve which concerns on one embodiment of this invention. It is the longitudinal cross-sectional view which expanded and specifically showed the damping valve of FIG. It is the figure which showed the pressure flow characteristic at the time of hydraulic fluid flowing from a compression side chamber to an extension side chamber in the shock absorber equipped with the damping valve concerning one embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings. The same reference numerals used throughout the several drawings indicate the same parts. The drawings are viewed in the direction of the reference numerals.

As shown in FIG. 1, a damping valve V1 according to an embodiment of the present invention is mounted on a shock absorber D that is interposed between a vehicle body B and a carriage W of a railway vehicle and suppresses vehicle body vibration. , Embodied in the piston portion of the shock absorber D.

The shock absorber D includes a cylindrical cylinder 1, a piston 10 inserted into the cylinder 1 so as to be axially slidable, and a rod 11 having one end connected to the piston 10 and the other end extending outside the cylinder 1. The outer cylinder 12 disposed on the outer periphery of the cylinder 1, the one end opening of the cylinder 1 and the outer cylinder 12 are closed, and the other end opening of the cylinder 1 and the outer cylinder 12 is closed. The bottom member 14 is provided. The shock absorber D is connected to the vehicle body B via a bracket 15 attached to the protruding end of the rod 11 protruding from the cylinder 1, and is connected to the carriage W via a bracket 16 attached to the bottom member 14. Therefore, when vibration is input to the carriage W, the rod 11 moves in and out of the cylinder 1 and the piston 10 moves in the cylinder 1 so that the shock absorber D expands and contracts.

In the cylinder 1, an extension side chamber L1 and a compression side chamber L2 defined by the piston 10 are formed, and the extension side chamber L1 and the compression side chamber L2 are filled with hydraulic oil, respectively. In addition, a reservoir R is formed between the cylinder 1 and the outer cylinder 12, and the hydraulic oil is stored and gas is sealed therein. The extension side chamber L1 and the pressure side chamber L2 are communicated with each other via the extension side flow path 2 and the pressure side flow path 3 provided in the piston 10, and the pressure side chamber L2 and the reservoir R are in the suction flow path 4 provided in the bottom member 14. And via the discharge channel 5.

Although not shown, the rod guide 13 is provided with an annular seal that is in sliding contact with the outer periphery of the rod 11. Further, a well-known seal or the like is provided between the cylinder 1 and the rod guide 13, between the cylinder 1 and the bottom member 14, between the outer cylinder 12 and the rod guide 13, and between the outer cylinder 12 and the bottom member 14. It is closed liquid-tightly. Therefore, the inside of the outer cylinder 12 is made a sealed space, and the hydraulic oil does not go back and forth inside the cylinder 1 without passing through the suction flow path 4 or the discharge flow path 5.

Subsequently, the extension side flow path 2 provided in the piston 10 includes a passage 20 that communicates the extension side chamber L1 and the compression side chamber L2, and an extension side valve V2 provided in the middle of the passage 20. . The expansion side valve V2 allows the flow of hydraulic oil from the expansion side chamber L1 toward the compression side chamber L2 through the passage 20 to provide resistance to the flow, and prevents the flow in the opposite direction.

Further, the pressure side flow path 3 provided in the piston 10 extends through a passage 30 that communicates the expansion side chamber L1 and the pressure side chamber L2, a pressure side valve V3 provided in the middle of the passage 30, and the pressure side valve V3. The bypass passage 33 communicates the side chamber L1 and the pressure side chamber L2, and a damping valve V1 provided in the middle of the bypass passage 33. The pressure side valve V3 allows the flow of hydraulic oil from the pressure side chamber L2 toward the extension side chamber L1 through the passage 30 to provide resistance to the flow, and blocks the flow in the opposite direction. The other damping valve V 1 forms an orifice in the middle of the bypass passage 33, and provides resistance to the flow of hydraulic oil moving through the bypass passage 33. Further, the damping valve V1 uses the pressure side chamber L2 as one chamber and the extension side chamber L1 as the other chamber, and allows the flow of hydraulic oil from the pressure side chamber L2 toward the extension side chamber L1 to pass through the orifice and to flow in the opposite direction. Stop. In addition, the damping valve V1 blocks communication of the bypass passage 33 when the pressure in the pressure side chamber L2 on the upstream side becomes higher than a predetermined value.

Subsequently, the suction flow path 4 provided in the bottom member 14 includes a passage 40 communicating the pressure side chamber L2 and the reservoir R, and a suction valve V4 provided in the middle of the passage 40. The suction valve V4 is a check valve, and allows the flow of hydraulic oil from the reservoir R to the pressure side chamber L2 through the passage 40 to block the flow in the opposite direction.

The discharge flow path 5 provided in the bottom member 14 includes a passage 50 that communicates the compression side chamber L2 and the reservoir R, and a discharge valve V5 provided in the middle of the passage 50. This discharge valve V5 allows the flow of hydraulic oil from the pressure side chamber L2 to the reservoir R through the passage 50 to provide resistance to the flow and block the flow in the opposite direction.

The expansion side valve V2, the pressure side valve V3, and the discharge valve V5 that provide resistance to the flow of the hydraulic oil that moves through the

passages

20, 30, 50, and make the

passages

20, 30, 50 one-way, have any structure. However, a conventionally known configuration can be adopted. For example, the expansion side valve V2, the pressure side valve V3, and the discharge valve V5 are energized in the direction of closing the

valve bodies

21, 31, 51 provided in the middle of the

passages

20, 30, 50, and the

valve bodies

21, 31, 51. Springs 22, 32, and 52. When the pressure on the upstream side of the

valve bodies

21, 31, 51 increases, the

valve bodies

21, 31, 51 retreat (lift) against the urging force of the

springs

22, 32, 52 and the

passages

20, 30, Open 50. Since the lift amount of the

valve bodies

21, 31, 51 increases in proportion to the pressure increase on the upstream side of the

valve bodies

21, 31, 51, the pressure flow characteristics (flow rate) of the extension side valve V2, the pressure side valve V3, and the discharge valve V5. The characteristic of the pressure with respect to is a characteristic of the valve proportional to the flow rate. The suction valve V4, which is a check valve for setting the passage 40 to one-way, can also employ a conventionally known configuration. Therefore, description of the detailed structure of the expansion side valve V2, the pressure side valve V3, the suction valve V4, and the discharge valve V5 is omitted.

Next, the specific structure of the damping valve V1 will be described below. As shown in FIG. 2, the damping valve V 1 is disposed on the valve body 6 accommodated in the valve hole H provided in the piston 10 and the extension side chamber L 1 on the downstream side of the valve body 6. A spring receiver 7 to be screwed, a coil spring 8 interposed between the valve body 6 and the spring receiver 7, and a check valve V6 accommodated in the valve body 6 are configured.

In the present embodiment, the piston 10 that divides the inside of the cylinder 1 into an extension side chamber L1 and a pressure side chamber L2 also serves as a housing in the damping valve V1, and a valve body 6 and a spring are placed in a valve hole H formed in the piston 10. The receiver 7, the coil spring 8, and the check valve V6 are accommodated. The housing of the damping valve V1 may be other than the piston 10. For example, the housing of the damping valve V1 according to the present invention may include a rod 11 or a nut (not shown) for fixing the piston 10 to the rod 11. It may be used as

A valve hole H formed in the piston 10 which is a housing passes through the piston 10 in the axial direction and communicates the extension side chamber L1 and the pressure side chamber L2. The valve hole H includes a screw hole 10a that is continuous from the upper side to the lower side in FIG. 2, a large diameter hole 10b, a guide hole 10c that has a smaller diameter than the large diameter hole 10b, and the guide hole 10c. And a protective hole 10d having a larger diameter.

A screw groove is formed in the wall surface of the screw hole 10a, and the spring receiver 7 is screwed together. The spring receiver 7 includes a protrusion 7a that protrudes toward the valve body 6, and the upper end of the coil spring 8 in FIG. 2 is fitted to the outer periphery of the protrusion 7a. Further, the spring receiver 7 is formed with a hole 7b penetrating the center of the spring receiver 7 in the axial direction and a plurality of engagement holes 7c opening upward in FIG. Then, when a tool or the like is engaged with the engagement hole 7c and the spring receiver 7 is rotated, the spring receiver 7 advances and retracts in the direction of the rotation axis, and stops when the rotation is stopped. Thus, in this embodiment, since the spring receiver 7 is screwed into the screw hole 10a, the axial position of the spring receiver 7 can be easily adjusted. The configuration for changing the axial position of the spring receiver 7 is not limited to this, and can be changed as appropriate.

Subsequently, the valve body 6 is accommodated in a space below the screw hole 10a in FIG. The valve body 6 is connected to a cylindrical sliding shaft portion 60a located at the tip which is the lower end of the valve body 6 in FIG. 2, and to the upper side in FIG. 2 of the sliding shaft portion 60a, and the sliding shaft portion 60a. A valve body 60 having a flange portion 60b having a larger outer diameter and a body portion 60c connected to the upper side in FIG. 2 of the flange portion 60b, and an upper end portion of the body portion 60c of the valve body 60 in FIG. And a cap 61. The valve body 6 is inserted into the valve hole H from the upper side in FIG. 2 of the valve hole H, the sliding shaft portion 60a is inserted through the guide hole 10c, and the upper side in FIG. It is accommodated in the large-diameter hole 10b.

The sliding shaft portion 60a of the valve main body 60 is in sliding contact with the wall surface of the guide hole 10c and can slide in the guide hole 10c in the axial direction. That is, in the present embodiment, the sliding shaft 60a is supported by the wall surface of the guide hole 10c so as to be movable in the axial direction, so that the valve body 6 can move forward and backward toward the pressure side chamber L2. In this Embodiment, the outer diameter of the valve body 6 is smaller than the diameter of the large diameter hole 10b, and the clearance gap s1 is made between the wall surfaces of the large diameter hole 10b. Therefore, even if the axes of the large-diameter hole 10b and the guide hole 10c are slightly deviated in the radial direction, the movement of the valve body 6 is not hindered, and the required accuracy in forming the valve hole H can be lowered. Processing for forming the hole H can be facilitated.

Subsequently, the outer diameter of the flange portion 60b of the valve body 60 is larger than the outer diameter of the trunk portion 60c, and the outer periphery of the flange portion 60b protruding from the trunk portion 60c to the outer peripheral side is shown in FIG. While supporting the middle and lower ends, the inner periphery of the coil spring 8 can be supported by the body 60c. The coil spring 8 is compressed in advance and exerts an elastic force, and urges the valve body 6 toward the pressure side chamber L2. An annular step 10e is formed on the wall surface of the valve hole H at the boundary between the large diameter hole 10b and the guide hole 10c. Since the outer diameter of the flange portion 60b is larger than the diameter of the guide hole 10c, if the valve body 6 continues to advance downward in FIG. 2, the flange portion 60b hits the step 10e, and further advancement cannot be performed. That is, in the present embodiment, the step 10e provided on the piston 10 functions as a stopper that restricts the advancement of the valve body 6 by a predetermined amount or more.

Therefore, in a state where no external force is applied to the damping valve V1, that is, in a no-load state, the valve body 6 is advanced as much as possible by receiving the biasing force of the coil spring 8, and the flange portion 60b is pressed against the step 10e. It becomes. The preset load of the coil spring 8 can be changed by changing the axial position of the spring receiver 7. Specifically, when the spring receiver 7 is rotated in the forward direction and advanced toward the valve body 6, the amount of compression of the coil spring 8 increases and the preset load increases. On the other hand, if the spring receiver 7 is rotated in the reverse direction and retracted away from the valve body 6, the amount of compression of the coil spring 8 is reduced and the preset load is reduced. Thus, in the present embodiment, the coil spring 8 functions as a biasing member that biases the valve body 6 toward the pressure side chamber L2, but as such a biasing member, a spring other than the coil spring or An elastic body such as rubber may be used.

Further, when the damping valve V1 is attached to the valve hole H and provided in the bypass passage 33, the valve body 6 receives the pressure of the compression side chamber L2 from the front side and the pressure of the extension side chamber L1 from the back side. Then, a force obtained by multiplying the pressure receiving area on the front side of the valve body 6 that receives the pressure in the compression side chamber L2 by the pressure in the compression side chamber L2 (hereinafter referred to as force F1) is the back surface of the valve body 6 that receives the pressure in the expansion side chamber L1. When the total force (hereinafter referred to as force F2) of the force obtained by multiplying the pressure receiving area on the side by the pressure of the expansion chamber L1 and the urging force of the coil spring 8 is exceeded, the valve body 6 is retracted. As described above, when the preset load is increased, the force F2 is increased, so that the pressure in the compression side chamber L2 required to retract the valve body 6 is increased. On the other hand, when the preset load is reduced, the force F2 is reduced, so that the pressure in the compression side chamber L2 required to retract the valve body 6 is reduced.

Subsequently, the axial length of the sliding shaft portion 60a of the valve body 60 is longer than the axial length of the guide hole 10c. Therefore, in a state where the flange portion 60b contacts the step 10e and the advancement of the valve body 6 is restricted, the tip end portion of the sliding shaft portion 60a protrudes into the protective hole 10d. Further, when the forward movement of the valve body 6 is restricted, the protruding amount of the sliding shaft portion 60a into the protective hole 10d is the largest. Even in this state, the lower end of the sliding shaft portion 60a in FIG. The axial length of the protective hole 10d is set so that does not protrude downward from the piston 10 in FIG. Thus, since the sliding shaft part 60a is accommodated in the protective hole 10d, the sliding shaft part 60a is protected by the piston 10, and interference between the sliding shaft part 60a and other members is prevented. Further, since the diameter of the protective hole 10d is larger than the outer diameter of the sliding shaft portion 60a, an annular gap s2 is formed along the circumferential direction on the outer periphery of the sliding shaft portion 60a inserted into the protective hole 10d.

Subsequently, a check valve accommodating hole 60d for accommodating the check valve V6 is formed inside the valve body 60 from the flange portion 60b to the body portion 60c. The other sliding shaft portion 60a is provided at the central portion of the sliding shaft portion 60a, and is connected to the check valve accommodating hole 60d. The shaft hole 60e extends radially from the shaft hole 60e. A plurality of lateral holes 60f are formed to open to the sides. The position of the lateral hole 60f is set so that the opening o1 of the lateral hole 60f is exposed in the protective hole 10d in a state where the advancement of the valve body 6 is restricted. Therefore, in a state where the forward movement of the valve body 6 is restricted, the compression side chamber L2 and the lateral hole 60f communicate with each other through a gap s2 that is formed on the outer periphery of the sliding shaft portion 60a. However, when the valve body 6 moves backward and all the openings o1 of the lateral holes 60f enter the guide holes 10c, the openings o1 are closed by the wall surfaces of the guide holes 10c, and the communication between the pressure side chamber L2 and the lateral holes 60f is established. Blocked.

In the present embodiment, the openings o1 of all the horizontal holes 60f are provided with substantially the same size and the same height (axial position). Furthermore, in the state where the forward movement of the valve body 6 is restricted, the upper end in FIG. 2 of the opening o1 is located at the boundary between the guide hole 10c and the protective hole 10d. Therefore, when the valve body 6 retreats (lifts) by an amount corresponding to the vertical width of the opening o1 of the horizontal hole 60f, the openings o1 of all the horizontal holes 60f are closed substantially simultaneously facing the wall surface of the guide hole 10c. The number, shape, and orientation of the horizontal holes 60f are not limited to the above, and can be changed as appropriate. Moreover, the timing which closes the opening o1 of the some horizontal hole 60f can also be changed suitably.

Subsequently, the check valve accommodating hole 60d connected to the horizontal hole 60f via the shaft hole 60e is opened above the trunk portion 60c in FIG. 2, and the opening end portion is a screw hole (not shown). . Then, the cap 61 is screwed into this screw hole. Further, the lower end portion of the check valve accommodating hole 60d in FIG. 2 is reduced in diameter, and an annular valve seat 60g is provided on the wall of the check valve accommodating hole 60d at the boundary of the portion where the diameter changes. Further, the cap 61 is formed with a hole 61a penetrating the cap 61 in the axial direction, and the space above the valve seat 60g in the check valve accommodating hole 60d is opened through the hole 61a in FIG. It communicates outside the body 6. Then, the shaft hole 60e of the sliding shaft portion 60a is connected to the space below the valve seat 60g in the other check valve housing hole 60d in FIG.

The check valve V6 includes a check valve valve body 9 that is slidably inserted into a space above the valve seat 60g in the check valve housing hole 60d in FIG. 2 and between the check valve valve body 9 and the cap 61. The coil spring 90 is interposed and configured to bias the check valve valve body 9 toward the valve seat 60g.

The check valve valve body 9 has a bottomed cylindrical valve head 9a whose bottom is seated on the valve seat 60g, and extends upward in FIG. 2 from the cylindrical portion of the valve head 9a and has a larger outer diameter than the valve head 9a. It has a cylindrical large-diameter portion 9b. The check valve valve body 9 has the large-diameter portion 9b in sliding contact with the inner periphery of the valve main body 60 and is movable in the axial direction. An annular gap s3 is formed on the outer periphery of the valve head 9a with the valve body 60, and a hole communicating the gap s3 and the inside of the valve head 9a is formed in the tubular portion of the valve head 9a. 9c is formed.

When the bottom of the valve head 9a is seated on the valve seat 60g, the communication between the shaft hole 60e and the check valve housing hole 60d is blocked. However, when the hydraulic oil that has flowed into the shaft hole 60e through the lateral hole 60f from the compression side chamber L2 retreats the check valve valve body 9 against the urging force of the coil spring 90, the hydraulic oil is separated from the valve head 9a. The gap formed between the valve seat 60g, the gap s3 formed on the outer periphery of the valve head 9a, the hole 9c of the valve head 9a, the inner side of the valve head 9a, the inner side of the large diameter portion 9b, and the hole 61a of the cap 61 are passed in this order. And flows out of the valve body 6. Thus, the hydraulic oil that has flowed out of the valve body 6 can move through the hole 7b of the spring receiver 7 to the extension side chamber L1.

That is, in the present embodiment, the flow path 62 is configured by including the horizontal hole 60f, the shaft hole 60e, the check valve accommodating hole 60d, and the hole 61a of the cap 61 provided in the valve body 6. One end of the cap 61 opens to the side of the sliding shaft portion 60a, and the other end opens to the upper side of the cap 61 in FIG. The flow path 62 and the hole 7b of the spring receiver 7 constitute a bypass path 33 that bypasses the compression side valve V3 (FIG. 1) and communicates the expansion side chamber L1 and the compression side chamber L2.

Also, the check valve V6 is provided in the middle of the flow path 62, and allows the flow of hydraulic oil from the pressure side chamber L2 toward the extension side chamber L1 through the flow path 62 to prevent the flow in the opposite direction. Therefore, the flow path 62 becomes one-way, and as a result, the bypass path 33 also becomes one-way. Further, in the present embodiment, the lateral hole 60f is narrowed to function as an orifice, and resistance is given to the flow of hydraulic oil that moves through the flow path 62 through the orifice (lateral hole 60f).

Next, the operation of the damping valve V1 according to this embodiment will be described.

The pressure in the pressure side chamber L2 that can retreat the valve body 6 is higher than the pressure in the pressure side chamber L2 that can retreat the check valve valve body 9. Therefore, if the pressure in the pressure side chamber L2 does not reach a pressure that can cause the check valve valve body 9 to retreat, the valve body 6 is advanced as much as possible by receiving the urging force of the coil spring 8, and the flange portion 60b is pressed against the step 10e. It becomes a state. In addition, the check valve valve body 9 also advances as much as possible by receiving the urging force of the coil spring 90, and the valve head 9a is seated on the valve seat 60g. Therefore, the flow path 62 provided in the valve body 6 is maintained in a closed state by the check valve V6. In this state, the sliding shaft portion 60a provided with the opening o1 of the lateral hole 60f serving as an opening on one end side of the flow path 62 protrudes into the protective hole 10d, and the gap s2 formed on the outer periphery of the sliding shaft portion 60a. The pressure side chamber L2 and the shaft hole 60e are communicated with each other through the horizontal hole 60f.

On the other hand, when the pressure in the pressure side chamber L2 rises higher than the pressure that can cause the check valve valve body 9 to retreat, the check valve valve body 9 retreats against the urging force of the coil spring 90, and the flow path 62 communicates. Is acceptable. Then, the hydraulic fluid that has flowed out from the opening o2 of the hole 61a that is the opening on the other end side of the flow path 62 flows out to the extension side chamber L1 through the hole 7b of the spring receiver 7.

As described above, since the horizontal hole 60f functions as an orifice, when the flow rate of the hydraulic fluid flowing through the flow path 62 is small, the hydraulic fluid passes through the orifice with relatively little resistance and passes from the compression side chamber L2 to the expansion side chamber L1. The differential pressure between the compression side chamber L2 and the extension side chamber L1 does not increase. However, when the flow rate increases, resistance is given by the orifice to the flow of hydraulic oil from the compression side chamber L2 toward the expansion side chamber L1, and the differential pressure between the compression side chamber L2 and the expansion side chamber L1 increases. The force F1 obtained by multiplying the pressure receiving area on the front side of the valve body 6 by the pressure of the pressure side chamber L2 is multiplied by the force obtained by multiplying the pressure receiving area on the back side of the valve body 6 by the pressure of the expansion side chamber L1 and the coil spring 8 is attached. When the total force F2 with the force is exceeded, the valve body 6 moves backward until the forces F1 and F2 are suspended. Thus, when the valve body 6 moves backward and moves until all the openings o1 of the lateral holes 60f face the wall surface of the guide hole 10c, the flow path 62 is closed, so that the communication of the bypass path 33 is blocked.

In the present embodiment, as shown in FIG. 1, a pressure side valve V3 is provided in parallel with the damping valve V1. When the pressure difference between the pressure side chamber L2 and the expansion side chamber L1 becomes a predetermined value or more, the valve body 31 of the pressure side valve V3 moves backward to open the passage 30, and the hydraulic oil in the pressure side chamber L2 passes through the passage 30 and enters the expansion side chamber L1. Moving. Thus, in the present embodiment, the pressure side flow path 3 that allows the flow of the hydraulic oil from the pressure side chamber L2 toward the expansion side chamber L1 is configured to have two paths, the passage 30 and the bypass path 33. When the communication of the bypass path 33 is blocked, the hydraulic oil in the compression side chamber L2 moves through the passage 30 to the extension side chamber L1.

More specifically, when the flow rate per unit time of the hydraulic oil flowing through the pressure side flow path 3 is small, the hydraulic oil passes through the bypass path 33, so that the pressure flow characteristic is as shown by the solid line X in FIG. This is an orifice-specific characteristic proportional to the square. When the flow rate per unit time increases, the bypass passage 33 is blocked by the damping valve V1 and the pressure side valve V3 opens the passage 30, so that the pressure flow characteristic is proportional to the flow rate as shown by the solid line Y in FIG. It becomes the characteristic peculiar to the valve.

Here, in a general damping valve configured to include a normally open type orifice and a poppet valve set to a predetermined valve opening pressure, the opening area of the orifice is increased and the flow rate per unit time is increased. If the pressure in the region where there is a small amount is lowered, the pressure in the region where the flow rate per unit time is large will be kept low. On the other hand, when an attempt is made to increase the pressure in a region where the flow rate per unit time is large, the orifice opening area cannot be increased, and the pressure in the region where the flow rate per unit time is small also increases (in FIG. 3). Dashed line Z). As described above, in a general damping valve, it is difficult to realize a pressure flow characteristic in which the pressure in a region where the flow rate per unit time is low is low and the pressure in a region where the flow rate is high is high.

On the other hand, in the present embodiment, the pressure flow characteristic when the bypass passage 33 is communicated can be freely set by the opening area of the lateral hole 60f, and the pressure flow characteristic when the bypass passage 33 is closed can be set to the pressure side valve V3. It can be set freely according to the specifications. That is, in the present embodiment, the pressure flow characteristics when the hydraulic oil passes through the pressure side flow path 3 can be set independently before and after the bypass path 33 is closed. Therefore, when the damping valve V1 is used, as shown by solid lines X and Y in FIG. 3, the pressure flow characteristics in which the pressure in the region where the flow rate per unit time is low is low and the pressure in the region where the flow rate is high are high. It can be easily realized.

Furthermore, the pressure when the valve body 6 closes the bypass passage 33 can be changed by rotating the spring receiver 7 and changing the axial position of the spring receiver 7. Specifically, when the spring receiver 7 is rotated in the forward direction and advanced toward the valve body 6, the preset load of the coil spring 8 increases, and the pressure side chamber when the valve body 6 closes the bypass path 33. The pressure of L2 can be increased. On the other hand, when the spring receiver 7 is rotated in the reverse direction and is retracted away from the valve body 6, the preset load of the coil spring 8 is reduced and the pressure side chamber L 2 is closed when the valve body 6 closes the bypass path 33. The pressure can be reduced.

Thus, in the present embodiment as well, the distance between the valve body 6 and the spring receiver 7 is changed by adjusting the preset load, as in the case of the conventional damping valve, but the valve body 6 closes the bypass passage 33. The required lift amount (retraction amount) of the valve body 6 is always constant. Specifically, the lift amount corresponds to the distance from the lower end in FIG. 2 of the wall surface of the guide hole 10c to the lower end of the opening o1 on one end side of the flow path 62. In the present embodiment, the lift amount of the flow path 62 is This corresponds to the vertical width in FIG. 2 of the opening o1 on one end side. Therefore, according to the damping valve V 1, it is possible to suppress the variation in the lift amount required for closing the flow path 62 from product to product. Further, the sliding shaft portion 60a in which the opening o1 is formed is a portion supported by the wall surface of the guide hole 10c and is not easily tilted. Therefore, the flow path 62 can be reliably closed when the opening o1 faces the wall surface. . Therefore, according to the damping valve V1, the flow path 62 can be reliably closed with a desired pressure.

Further, in the present embodiment, a plurality of lateral holes 60f for guiding hydraulic oil from the compression side chamber L2 to the shaft hole 60e are formed, and the opening area on one side of the flow path 62 is the opening o1 of each lateral hole 60f. The total area of As described above, since the plurality of horizontal holes 60f are provided, the diameter of the opening o1 of each horizontal hole 60f can be reduced while securing the opening area on one side of the flow path 62. And if the opening diameter of each horizontal hole 60f is made small in this way, the lift amount of the valve body 6 required for closing the flow path 62 can be made small. For this reason, it is possible to further suppress variations in the pressure in the pressure side chamber L2 when the flow path 62 is closed by the valve body 6.

Next, the operation of the shock absorber D provided with the damping valve V1 according to the present embodiment will be described.

When the shock absorber D extends, the rod 11 moves to the left side in FIG. 1 with respect to the cylinder 1, the piston 10 moves to the left side in FIG. 1 in the cylinder 1, and the expansion side chamber L1 is compressed and the pressure side chamber is compressed. L2 expands.

Then, the pressure in the expansion side chamber L1 to be compressed rises, and the hydraulic oil in the expansion side chamber L1 pushes open the expansion side valve V2, passes through the expansion side flow path 2, and moves to the compression side chamber L2. In the cylinder 1, the hydraulic oil corresponding to the retracted rod volume is insufficient, but the suction valve V 4 is opened, and hydraulic oil corresponding to the shortage is supplied from the reservoir R to the pressure side chamber L 2 through the suction flow path 4. . Since the resistance by the extension side valve V2 is given to the flow of the hydraulic fluid from the extension side chamber L1 toward the compression side chamber L2, the pressure in the extension side chamber L1 increases. On the other hand, since the pressure side chamber L2 receives the supply of hydraulic oil from the reservoir R, the pressure side chamber L2 becomes substantially equal to the pressure in the reservoir R. Therefore, a differential pressure is generated in the pressures of the extension side chamber L1 and the compression side chamber L2, and this differential pressure acts on the piston 10, and the shock absorber D exerts an extension side damping force that prevents the extension operation.

On the contrary, when the shock absorber D contracts, the rod 11 moves to the right in FIG. 1 with respect to the cylinder 1, the piston 10 moves to the right in FIG. 1 in the cylinder 1, and the compression side chamber L2 is compressed. In addition, the extension side chamber L1 is enlarged.

Then, when the pressure in the compression side chamber L2 to be compressed rises and the piston speed is low, the flow rate per unit time is small, so the hydraulic oil in the compression side chamber L2 opens the check valve V6 of the damping valve V1, It moves through the bypass path 33 to the extension side chamber L1. When the piston speed increases and the flow rate per unit time increases, the hydraulic oil in the compression side chamber L2 moves the valve body 6 backward, so that the damping valve V1 closes the bypass passage 33. When the bypass passage 33 is closed, the hydraulic oil in the pressure side chamber L2 pushes open the pressure side valve V3 and moves through the passage 30 to the extension side chamber L1. In the cylinder 1, the hydraulic oil corresponding to the volume of the rod that has entered becomes surplus, but the surplus hydraulic oil opens the discharge valve V 5, passes through the discharge flow path 5, and is discharged from the pressure side chamber L 2 to the reservoir R. . A resistance is given to the flow of hydraulic oil from the pressure side chamber L2 toward the extension side chamber L1 and the reservoir R by the lateral hole 60f or the pressure side valve V3 functioning as an orifice, and the discharge valve V5, so that the pressure in the pressure side chamber L2 is reduced. To rise. On the other hand, since the pressure in the expanding side chamber L1 is reduced, a pressure difference is generated between the pressure side chamber L2 and the pressure side chamber L1, and this differential pressure acts on the piston 10 so that the shock absorber D is contracted. Demonstrates compression-side low-speed damping force that prevents

Here, the pressure flow characteristics when the hydraulic oil passes through the pressure side flow path 3 are such that the differential pressure between the pressure side chamber L2 and the expansion side chamber L1 is small in the region where the flow rate per unit time is small as described above. Is set. For this reason, in the low speed region where the hydraulic oil passes through the orifice of the bypass passage 33, the differential pressure between the compression side chamber L2 and the expansion side chamber L1 becomes small, so that substantially equal pressure is applied to both the left and right sides of the piston 10 in FIG. The apparent pressure receiving area is close to the cross-sectional area of the rod 11. Further, as described above, the pressure flow characteristic when the hydraulic oil passes through the pressure side flow path 3 is set so that the differential pressure between the pressure side chamber L2 and the extension side chamber L1 becomes large in a region where the flow rate per unit time is large. Has been. For this reason, while the communication of the bypass path 33 is interrupted, the differential pressure between the compression side chamber L2 and the expansion side chamber L1 increases in a high speed region where the hydraulic oil passes through the compression side valve V3. Therefore, the pressure applied to the right side in FIG. 1 of the piston 10 is larger than the pressure applied to the left side in FIG. 1, and the apparent pressure receiving area of the piston 10 is the difference between the cross-sectional area of the piston 10 and the cross-sectional area of the rod 11 (piston 10 cross-sectional area-cross-sectional area of the rod 11).

That is, when the pressure flow characteristic of the hydraulic fluid from the compression side chamber L2 to the expansion side chamber L1 is set as described above using the damping valve V1, the flow rate of the flow passage 62 is apparently dependent on the piston speed. It appears that the pressure receiving area of the piston 10 has changed. When the apparent pressure receiving area of the piston 10 decreases, the damping force generation response of the shock absorber D decreases. On the contrary, when the apparent pressure receiving area of the piston 10 increases, the damping force generation response of the shock absorber D. Improves. Therefore, when the damping valve V1 is used for the pressure side flow path 3, the apparent pressure receiving area of the piston 10 can be switched by opening and closing the flow path 62, and the damping force generation response can be easily changed according to the speed.

In the present embodiment, the damping valve V1 according to the present invention is mounted on the shock absorber D for railway vehicles. However, the present invention is not limited to this. For example, a shock absorber used for damping a structure, Or you may mount in another buffer. The configuration of the shock absorber D is not limited to the above, and can be changed as appropriate. For example, a fluid other than hydraulic oil may be used as the fluid for generating the damping force. Moreover, the rod 11 may extend on both sides of the piston 10, and the shock absorber D may be a double rod type. In addition, a reservoir R is formed between the cylinder 1 and the outer cylinder 12 that are arranged in the inner and outer doubles. A separate tank is provided outside the cylinder 1, and the reservoir R is formed in the tank. May be. Further, the shock absorber D may be a uniflow type in which hydraulic oil circulates always in one direction in the order of the pressure side chamber L2, the extension side chamber L1, and the reservoir R. And according to such a form of the shock absorber D, the position where the damping valve V1 is provided and the type of the mounted valve can be changed as appropriate.

Hereinafter, the operational effects of the damping valve V1 and the shock absorber D equipped with the damping valve V1 in the present embodiment will be described.

In the present embodiment, the shock absorber D is inserted into the cylinder 1 so as to be axially movable in the cylinder 1 and divides the inside of the cylinder 1 into an extension side chamber (other chamber) L1 and a pressure side chamber (one chamber) L2. A piston 10, a rod 11 having one end connected to the piston 10 and penetrating through the expansion side chamber L1 and the other end extending outside the cylinder 1, a reservoir R for storing hydraulic oil (fluid), an expansion side chamber L1, and a compression side chamber The expansion side flow path 2 having the expansion side valve V2 that communicates with L2 and allows the flow of hydraulic oil from the expansion side chamber L1 toward the compression side chamber L2 to provide resistance to the flow, and the expansion side chamber L1 and the compression side chamber L2. , A pressure side flow path 3 having a pressure side valve V3 and a damping valve V1 that allows the flow of hydraulic oil from the pressure side chamber L2 toward the expansion side chamber L1 and provides resistance to this flow, and the pressure side chamber L2 and the reservoir R. Communication, pressure side from reservoir R The suction flow path 4 having a suction valve V4 that allows the flow of hydraulic oil toward L2, the pressure side chamber L2, and the reservoir R communicate with each other to allow the flow of hydraulic oil toward the reservoir R from the pressure side chamber L2 and this flow. And a discharge passage 5 having a discharge valve V5 that provides resistance to the. The pressure side flow path 3 communicates the expansion side chamber L1 and the pressure side chamber L2, and bypasses the pressure side valve V3, bypasses the expansion side chamber L1 and the pressure side chamber L2, and attenuates. And a bypass path 33 provided with a valve V1.

According to the above configuration, the damping valve V1 can block the flow path 62 and block the communication of the bypass path 33 by increasing the piston speed. Therefore, according to the shock absorber D, it is possible to change the apparent pressure receiving area of the piston 10 at the speed at which the damping valve V1 closes the flow path 62, thereby changing the damping force generation responsiveness. .

In addition, the structure of the buffer D which mounts the damping valve V1 which concerns on this invention is not restricted above, but can be changed suitably. For example, in the shock absorber D, the apparent pressure receiving area of the piston 10 can be switched between an area close to the cross-sectional area of the rod 11 and an area close to the difference between the cross-sectional area of the piston 10 and the cross-sectional area of the rod 11. However, the same effect can be obtained even if one of the pressure side valve V3 and the discharge valve V5 is eliminated. In addition, when the suction passage on the extension side chamber L1 side that allows the extension side chamber L1 and the reservoir R to communicate with each other and allows the flow of hydraulic oil from the reservoir R to the extension side chamber L2, an apparent pressure receiving area of the piston 10 is obtained. The area can be switched between an area close to the cross-sectional area of the rod 11 and an area close to the cross-sectional area of the piston 10. Such a change in the damping force generation responsiveness by opening and closing the flow path 62 can be realized if the damping valve V 1 is provided in the middle of the pressure side flow path 3.

In the damping valve V1 of the present embodiment, the flow path 62 has a shaft hole 60e formed at the center of the sliding shaft portion 60a, and extends from the shaft hole 60e to the side of the sliding shaft portion 60a. It has a plurality of lateral holes 60f that open.

According to the above configuration, it is possible to reduce the lift amount of the valve element 6 required to close the flow path 62 while securing the opening area on one end side of the flow path 62. Therefore, it is possible to suppress variation in the pressure in the pressure side chamber L2 when the flow path 62 is closed by the valve body 6.

In the present embodiment, the plurality of horizontal holes 60f extend radially from the shaft hole 60e, but this is not restrictive. For example, the plurality of lateral holes 60f may extend substantially parallel to the diameter of the sliding shaft portion 60a while intersecting the shaft hole 60e. Furthermore, in the present embodiment, the horizontal hole 60f functions as an orifice, but an orifice may be provided in a portion other than the horizontal hole 60f in the flow path 62, and the throttle provided in the middle of the flow path 62 is a choke other than the orifice. There may be no restriction, and no restriction may be provided in the middle of the flow path 62. Such a change is possible regardless of the type of shock absorber on which the damping valve V1 according to the present invention is mounted.

Further, in the damping valve V1 of the present embodiment, the valve hole H is connected to the guide hole 10c into which the sliding shaft portion 60a is slidably inserted and the pressure side chamber (one chamber) L2 side of the guide hole 10c. The valve body 6 has a protective hole 10d that allows the passage 62 to communicate and accommodates the sliding shaft portion 60a in a state in which the movement of the valve body 6 to the pressure side chamber L2 side is restricted by the step (stopper) 10e. Configured.

According to the above configuration, the outer periphery of the sliding shaft portion 60a is covered with the wall surface of the protective hole 10d while allowing the flow path 62 to communicate. That is, since the sliding shaft portion 60a does not protrude from the piston 10 which is a housing, the sliding shaft portion 60a can be protected and interference between the sliding shaft portion 60a and other members can be prevented.

If there is no concern about interference between the sliding shaft portion 60a and other members due to the structure of the shock absorber D or the position where the damping valve V1 is provided, the portion of the piston 10 where the protective hole 10d is formed is formed. The sliding shaft portion 60a may be omitted below the lower surface of the piston 10 in FIG. Such a change is possible regardless of the type of the shock absorber on which the damping valve V1 according to the present invention is mounted and the configuration of the flow path 62.

In the present embodiment, the flow path 62 is provided with a check valve V6 that allows only the flow of hydraulic fluid (fluid) from the pressure side chamber (one chamber) L2 side to the extension side chamber (other chamber) L1 side. .

According to the above configuration, since the flow path 62 can be made one-way, the flow path 62 can be maintained closed when the pressure in the extension side chamber L1 on the downstream side of the damping valve V1 increases. Therefore, for example, when a normally open orifice is provided and the shock absorber D extends at a low speed, when the hydraulic oil moves from the expansion side chamber L1 to the pressure side chamber L2 through the orifice, the check valve V6 is used. When the is provided, the extension side low speed damping force and the compression side low speed damping force can be individually set.

Note that the check valve V6 may be omitted if the hydraulic oil may be allowed to pass in both directions. In this case, since the cap 61 and the valve seat 60g of the valve body 6 can be omitted, the structure of the damping valve V1 can be simplified. In addition, in this embodiment, since the check valve V6 is accommodated in the valve body 6 of the damping valve V1, the damping valve V1 is not bulky in the axial direction. Can be changed as appropriate. For example, the check valve V6 may be attached to the spring receiver 7. Such changes are possible regardless of the type of shock absorber on which the damping valve V1 according to the present invention is mounted, the configuration of the flow path 62, and the configuration of the valve hole H.

Further, in the present embodiment, the damping valve V1 includes a step (stopper) 10e that regulates the forward movement (movement toward the pressure side chamber L2) of the valve body 6. When the valve body 6 is restricted from moving forward (moving toward the pressure side chamber (one chamber) L2) by the step (stopper) 10e, communication between the flow path 62 and the pressure side chamber L2 is allowed.

According to the above configuration, the pressure flow characteristics when the hydraulic oil (fluid) flows from the pressure side chamber (one chamber) L2 to the extension side chamber (other chamber) L1 can be switched before and after the flow path 62 is closed. However, for example, when the valve body 6 is restricted from moving forward, the communication between the flow path 62 and the pressure side chamber L2 is set to be blocked, and when the pressure in the pressure side chamber L2 becomes a predetermined pressure, The communication of the flow path 62 is allowed, and the flow path 62 may be set to be closed when the pressure becomes higher. Such a change is possible regardless of the type of the shock absorber on which the damping valve V1 according to the present invention is mounted, the configuration of the flow path 62, the configuration of the valve hole H, and the position and presence of the check valve V6.

Further, the damping valve V1 of the present embodiment is slid into the valve hole H and a piston (housing) 10 having a valve hole H communicating the pressure side chamber (one chamber) L2 and the expansion side chamber (other chamber) L1. A valve body 6 having a sliding shaft portion 60a that can be inserted, a coil spring (elastic member) 8 that biases the valve body 6 toward the pressure side chamber L2, and a side of the sliding shaft portion 60a at one end. And a flow path 62 having the other end opened to the extension side chamber L1 side from the sliding shaft portion 60a of the valve body 6. Then, when the valve body 6 moves to the extension side chamber L1 side, the opening o1 on one end side of the flow path 62 faces the wall surface of the guide hole 10c (the wall surface of the valve hole H slidably contacting the outer periphery of the sliding shaft portion 60a). The flow path 62 is closed.

According to the above configuration, the pressure flow characteristics when hydraulic fluid (fluid) flows from the pressure side chamber (one chamber) L2 to the extension side chamber (other chamber) L1 can be freely set before and after the flow path 62 is closed. . Further, in a state in which the valve body 6 is restricted from moving forward, the valve body 6 can be set to receive the urging force of the coil spring (elastic member) 8 and be pressed against the step (stopper) 10e. The load can be set easily. Even when the preset load is adjusted, the lift amount of the valve body 6 required to close the flow path 62 is the lower end of the opening o1 on the one end side of the flow path 62 from the lower end in FIG. 2 of the wall surface of the guide hole 10c. It corresponds to the distance up to and is constant. Therefore, it is possible to suppress variation in the lift amount of the valve body 6 required for closing the flow path 62 from product to product. In addition, an opening o1 on one end side of the flow path 62 opened and closed by the wall surface of the guide hole 10c is provided in the sliding shaft portion 60a that is in sliding contact with the wall surface. Since the portion is difficult to tilt, the flow path 62 can be reliably closed when the opening o1 faces the wall surface of the guide hole 10c. Therefore, according to the damping valve V1, the flow path 62 can be reliably closed with a desired pressure.

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

This application claims priority based on Japanese Patent Application No. 2015-112794 filed with the Japan Patent Office on June 3, 2015, the entire contents of which are incorporated herein by reference.

Claims

A damping valve,
A housing having a valve hole communicating between the one chamber and the other chamber;
A valve body having a sliding shaft portion slidably inserted into the valve hole;
An elastic member for urging the valve body toward the one chamber;
One end opens to the side of the sliding shaft portion and the other end includes a flow path opening to the other chamber side from the sliding shaft portion of the valve body,
When the valve body moves to the other chamber side and the opening on the one end side of the flow channel faces the wall surface of the valve hole that is in sliding contact with the outer periphery of the sliding shaft portion, the flow channel is closed. A damping valve characterized by
A damping valve according to claim 1,
With a stopper that restricts the movement of the valve body toward the one chamber,
In the state in which the valve body is restricted from moving toward the one chamber by the stopper, communication between the flow path and the one chamber is allowed.
A damping valve according to claim 1,
A damping valve characterized in that a check valve that allows only a flow of fluid from the one chamber side toward the other chamber side is provided in the flow path.
A damping valve according to claim 2,
The valve hole is
A guide hole into which the sliding shaft portion is slidably inserted;
Protection that accommodates the sliding shaft portion while allowing the passage to communicate with the guide hole in a state where the valve body is restricted from moving toward the one chamber by the stopper. A damping valve characterized by comprising a hole.
A damping valve according to claim 1,
The flow path is
A shaft hole formed in a central portion of the sliding shaft portion;
A damping valve comprising: a plurality of lateral holes extending from the shaft hole and opening to the side of the sliding shaft portion.
A shock absorber,
A cylinder,
A piston that is inserted into the cylinder so as to be axially movable and divides the cylinder into an extension side chamber and a pressure side chamber;
A pressure-side flow path that allows the flow of fluid from the pressure-side chamber to the extension-side chamber;
The damping valve according to claim 1 provided in the middle of the pressure side flow path,
The extension chamber is the other chamber;
The pressure side chamber is the one chamber;
The shock absorber, wherein the piston is the housing.
The shock absorber according to claim 6, wherein
A rod having one end connected to the piston and penetrating the extension side chamber, the other end extending outside the cylinder;
A reservoir for storing fluid;
An extension-side flow path having an extension-side valve that communicates the extension-side chamber and the compression-side chamber, allows a flow of fluid from the extension-side chamber toward the compression-side chamber, and gives resistance to the flow;
A suction flow path having a suction valve communicating the pressure side chamber and the reservoir and allowing a flow of fluid from the reservoir toward the pressure side chamber;
A discharge passage having a discharge valve that communicates the pressure side chamber and the reservoir, allows a flow of fluid from the pressure side chamber toward the reservoir, and provides resistance to the flow;
The pressure-side flow path is provided in the passage that communicates the extension side chamber and the pressure-side chamber, and a pressure-side valve that allows the flow of fluid from the pressure-side chamber toward the extension-side chamber and provides resistance to the flow. And a bypass path that bypasses the pressure side valve and communicates the extension side chamber and the pressure side chamber,
The damping valve is provided in the bypass path.