JP5659055B2 - Damping valve - Google Patents

Description

  The present invention relates to an improved damping valve.

  The damping valve gives resistance to the flow of the working fluid that accompanies expansion and contraction of the shock absorber, and exerts a damping force on the shock absorber. For example, it is incorporated in a rod guide in a multi-tube shock absorber or in a piston. Used. The rod guide is slidably inserted into the cylinder by being fitted to both ends of the cylinder and an outer cylinder that is disposed outside the cylinder and forms a reservoir with the cylinder. A piston rod connected to the piston is pivotally supported.

  And, for example, in the damping valve incorporated in the rod guide of the double cylinder type shock absorber, a valve hole provided in the rod guide and communicated with the upstream cylinder and the downstream reservoir, A valve seat provided on the inner periphery of the valve hole, a valve body that is inserted into the valve hole so as to be movable in the axial direction, and a coil spring that biases the valve body toward the valve seat (for example, , See Patent Document 1).

  Further, the multi-cylinder shock absorber divides the rod side chamber and the piston side chamber filled with the working fluid in the cylinder, and only the flow of the working fluid from the piston side chamber toward the rod side chamber, and the piston connected to the piston rod. A check valve that is allowed and a suction valve that allows only a flow of working fluid from the reservoir to the piston side chamber are provided, and the valve hole communicates the rod side chamber in the cylinder and the reservoir.

  This double-cylinder shock absorber discharges the working fluid from the cylinder to the reservoir through the valve hole regardless of whether it is extended or contracted. A damping force is exerted by applying resistance to the flow of the working fluid. Note that the working fluid that is insufficient in the cylinder at the time of extension is supplied into the cylinder via the suction valve.

JP 2002-349629 A

  In this conventional damping valve, the valve body is urged by a coil spring, the valve opening pressure is adjusted by the initial load of the coil spring, and the spring constant of the coil spring is used in the double cylinder type shock absorber. The attenuation characteristic can be adjusted.

  However, in such a damping valve that biases the valve body with a coil spring, if the double-tube shock absorber exhibits high speed operation, that is, if the double-tube shock absorber repeatedly expands and contracts at high speed, There is a problem that the axial vibration of the valve body is excited and oscillates due to the pressure fluctuation, and the damping force generated by the double-cylinder shock absorber becomes unstable and vibrates.

  Therefore, the present invention was devised in order to improve the above-mentioned problems, and the object of the present invention is to provide a damping that can suppress the oscillation of the valve body and generate a stable damping force in the shock absorber. It is to provide a valve.

  In order to achieve the above-described object, the problem solving means of the present invention is configured such that one chamber of the two chambers formed in the shock absorber is in the upstream and the other chamber is in the downstream and communicated with the one chamber. A housing having a valve hole having an annular valve seat; a valve body which is inserted in the valve hole so as to be movable in the axial direction; and is attached to and detached from the annular valve seat; A port communicating with the other chamber, a spring seat accommodated in the valve hole, and interposed between the valve body and the spring seat to urge the valve body toward the annular valve seat side. A tubular collar that is accommodated in the valve hole, accommodates the valve body inward, and forms an annular gap between the valve hole and the inner periphery of the valve hole. The collar communicates inward with the annular gap and faces the outer periphery of the valve body in the radial direction. That includes a through hole, to form a variable throttle in the above through hole and the valve body, characterized in that the flow path area of the variable throttle in spaced from the annular valve seat of the valve body increases.

  According to the damping valve of the present invention, even if the shock absorber operates at high speed and the flow rate of the fluid passing through the damping valve increases, the lateral vibration of the coil spring is suppressed and the axial vibration of the valve body is suppressed. A stable damping force can be exhibited without exciting the.

It is sectional drawing of the double cylinder type shock absorber with which the damping valve in one Embodiment was mounted. It is an expanded side sectional view of the damping valve in one embodiment. It is a perspective view of the collar of the damping valve of one embodiment. It is an expanded side sectional view of a damping valve in one modification of an embodiment.

  The present invention will be described below based on the embodiments shown in the drawings. As shown in FIGS. 1 and 2, the damping valve 1 in one embodiment is provided in a rod guide 2 fitted to both ends of a cylinder 20 and an outer cylinder 21 in a shock absorber D. The rod guide 2 is provided with a valve hole 3 having an annular valve seat 4 in the middle of the rod guide 2, which is communicated with a rod side chamber R 1 as one chamber, and the rod guide 2 having the valve hole 3. The valve body 5 is inserted into the valve hole 3 so as to be movable in the left-right direction in FIGS. 1 and 2, which is the axial direction, and is opened and closed from the side of the valve hole 3. Port 11 communicated with the reservoir R, the spring seat 10 housed in the valve hole 3, and the valve body 5 and the spring seat 10 are interposed between the valve body 5 toward the annular valve seat side. An energizing coil spring 6 and an annular shape from the outer peripheral side of the spring seat 10 in the valve hole 3 Rising coil spring 6 is configured with a cylindrical collar 7 which is inserted toward the seat side.

  On the other hand, a shock absorber D to which the damping valve 1 is applied includes a cylinder 20, an outer cylinder 21 that forms a reservoir R between the cylinder 20, and a cylinder 20 that is slidably inserted into the cylinder 20. A piston 22 partitioned into a rod side chamber R1 and a piston side chamber R2 filled with working oil as a working fluid, a piston rod 23 movably inserted into the cylinder 20 and connected to the piston 22, and the cylinder 20 and the outside A rod guide 2 fitted to both ends of the cylinder 21 to pivotally support the piston rod 23, a partition member 24 fitted to the lower end of the cylinder 20 in FIG. 1, and a lower end of the outer cylinder 21 in FIG. A lid 25 for closing, a piston passage 26 communicating with the piston side chamber R2 and the rod side chamber R1 provided in the piston 22, and a piston side provided in the piston passage 26 from the piston side chamber R2 to the rod side. A check valve 27 that allows only the flow of hydraulic oil toward R1, a suction passage 28 that is provided in the partition member 24 and communicates the reservoir R and the piston side chamber R2, and a suction passage 28 that is provided in the suction passage 28 from the reservoir R to the piston. A suction valve 28a that allows only the flow of hydraulic oil toward the side chamber R2 is provided, and is a double cylinder type shock absorber. In addition to the working oil, it is possible to employ a working fluid that can be applied to a shock absorber such as gas, water, aqueous solution, electrorheological fluid, and magnetorheological fluid.

  When the shock absorber D extends and the piston 22 moves upward in FIG. 1, the pipe 9 connected to the valve hole 3 and the port 11 from the rod side chamber R1 where the damping valve 1 is opened and compressed is compressed. The hydraulic fluid flows to the reservoir R through the pressure, and resistance is given to the flow of the hydraulic fluid by the damping valve 1 so that the rod side chamber R1 is pressurized, and the shock absorber D exhibits a damping force that suppresses the extension operation. In this extension operation, the piston 22 moves up in FIG. 1 to increase the volume of the piston-side chamber R2. However, the suction valve 28a provided in the suction passage 28 opens and the hydraulic oil corresponding to the increase is stored in the reservoir R. To the piston side chamber R2.

  When the shock absorber D is contracted and the piston 22 moves downward in FIG. 1, the check oil 27 provided in the piston passage 26 is opened and compressed from the piston side chamber R2 to the rod side chamber R1. Since the hydraulic fluid corresponding to the volume of the piston rod 23 entering the cylinder 20 becomes excessive in the cylinder 20, the damping valve 1 is opened and the excessive hydraulic fluid is supplied to the valve hole 3 and The hydraulic oil flows to the reservoir R through the pipe 9, and resistance is given to the flow of the hydraulic oil by the damping valve 1, so that the overall pressure in the cylinder 20 rises, and the shock absorber D has a damping force that suppresses the contraction operation. Demonstrate.

  In other words, the shock absorber D is operated by the hydraulic oil flowing from the rod side chamber R1 through the damping valve 1 to the reservoir R and repeating the expansion and contraction operation during the extension operation and the contraction operation. Is set to a uniflow type shock absorber that circulates in the order of the rod side chamber R1, the reservoir R, the piston side chamber R2, and the rod side chamber R1. That is, in this case, one chamber upstream of the damping valve 1 formed in the shock absorber D is the rod-side chamber R1, and the other chamber downstream is the reservoir R.

  Hereinafter, the damping valve 1 will be described in detail. The rod guide 2 has a cylindrical shape, and the outer periphery is fitted to the inner periphery of the outer cylinder 21 at the upper end in FIG. 1 and the inner periphery is fitted to the outer periphery of the upper end of the cylinder 20 in FIG.

  Further, the inner peripheral diameter of the lower end in FIG. 1 of the rod guide 2 is set to a diameter that can be fitted to the outer periphery of the cylinder 20, and the upper inner periphery in FIG. A recess 2a to which a seal member 40 is attached is formed, and a cylindrical bearing 41 slidably contacting the outer periphery of the piston rod 23 is mounted on the inner periphery and below the recess 2a. Further, the inner diameter of the intermediate portion 2 b that is the inner circumference of the rod guide 2, below the mounting portion of the bearing 41 and above the fitting portion of the cylinder 20, is set larger than the outer diameter of the piston rod 23. A gap is formed between the piston rod 23 and the piston rod 23.

  Subsequently, the valve hole 3 provided in the rod guide 2 opens from the outer periphery of the rod guide 2 and passes through the intermediate portion 2 b, and opens from the end of the rod guide 2 facing the reservoir R to reach the middle of the valve hole 3. The port 11 communicates with the reservoir R.

  The valve hole 3 has an inner diameter of the intermediate portion 2b of the rod guide 2 and a small diameter portion 3a communicating with the rod side chamber R1, and a large diameter portion having an inner diameter continuous with the small diameter portion 3a larger than the small diameter portion 3a. 3b, an annular valve seat 4 provided on the inner peripheral edge of the step portion 3c between the small diameter portion 3a and the large diameter portion 3b, and a screw portion 3d provided on the inner periphery on the right end in FIG. 2 of the large diameter portion 3b. A collar 7 is screwed to the screw portion 3d.

  A port 11 that opens from the middle of the large-diameter portion 3b of the valve hole 3 to the end facing the reservoir R of the rod guide 2 is provided. The port 11 is also provided with a screw portion 11a. Then, the pipe 9 is fixed to the rod guide 2 by screwing the screw 9a provided on the outer periphery of the upper end in FIG. The pipe 9 is protruded and accommodated in the reservoir R, and its lower end opening end in FIG. Therefore, the rod side chamber R1 of the cylinder 20 and the reservoir R are communicated with each other through the valve hole 3, the port 11, and the pipe 9. The pipe 9 may be fixed to the port 11 by press-fitting or welding other than screw connection.

  The valve body 5 is accommodated in the valve hole 3 so as to be movable in the axial direction. The valve body 5 includes a chamfer 5e provided on the outer periphery of the annular valve seat side end and a plurality of notches 5f provided on the outer periphery. The disc-shaped valve part 5a to be detached and attached, the columnar shaft part 5b extending from the left end in FIG. 2 which is the annular valve seat side end of the valve part 5a, and the anti-annular valve seat side of the valve part 5a in FIG. A spring fitting portion 5c protruding rightward and a groove 5d provided in the shaft portion 5b are provided.

  The shaft portion 5 b is slidably inserted into a small diameter portion 3 a that is the inner periphery of the annular valve seat 4 in the valve hole 3, and the valve body 5 is swung with respect to the valve hole 3 using the shaft portion 5 b as a guide. It can move in the axial direction without any problems.

  When the left end of the valve portion 5 a in FIG. 2 is brought into contact with the right end surface of the annular valve seat 4 in FIG. 2, the damping valve 1 is closed and the flow of hydraulic oil into the valve hole 3 is blocked. Can be done. Further, the shaft portion 5b is provided with a U-shaped groove 5d from the distal end to the proximal end, and the annular valve seat side end which is the left end in FIG. 2 of the valve portion 5a is the right end surface in FIG. 2, the groove 5d enters the inside of the valve hole 3 from the small diameter portion 3a and the damping valve 1 is opened according to the retracted amount. The hydraulic oil can flow into the valve hole 3 through the groove 5d. That is, the valve opening area of the damping valve 1 increases as the retraction amount of the valve portion 5a in the valve body 5 increases. The shape of the shaft portion 5b is not limited to the above, and in particular, a guide shaft and a bearing that supports the guide shaft are provided at the tip and the spring seat of the spring fitting portion 5c of the valve body 5. In this case, it is not necessary to obtain a guide function for the shaft portion 5b.

  Further, a bottomed cylindrical collar 7 is accommodated in the large diameter portion 3 b of the valve hole 3. The collar 7 includes a cylindrical portion 7 a and a bottom portion 7 b, and the cylindrical portion 7 a abuts on the stepped portion 3 c of the valve hole 3 to form an annular gap A between the large diameter portion 3 b of the valve hole 3. And a screw portion 7d that is screwed into a screw portion 3d that is formed in the large-diameter portion 3b of the valve hole 3 so as to be continuous with the reduced-diameter portion 7c.

  As shown in FIGS. 2 and 3, the reduced diameter portion 7 c is provided with rectangular through holes 7 e communicating with the annular gap A in the collar 7 at three equal intervals in the circumferential direction. The three through-holes 7e are opposed to the outer periphery of the valve portion 5a in the valve body 5 in the radial direction in the stroke range of the valve body 5. In addition, the shape and the number of installation of the through-hole 7e can be changed arbitrarily.

  In the damping valve 1, when the valve body 5 is seated on the annular reduction seat 4, the annular valve seat side end of the valve portion 5a and the annular valve seat side end of the through hole 7e are at the same level. Then, the flow path is limited by making the outer periphery of the valve portion 5a of the valve body 5 face the through hole 7e, and when the valve body 5 moves backward in the direction away from the annular valve seat 4 to the right in FIG. The through hole 7e is greatly opened to increase the flow path. That is, the valve body 5 and the through hole 7e constitute a variable throttle, and as the variable throttle is retracted from the annular valve seat 4, the opening degree of the through hole 7e increases. The channel area is increased. Thus, in this damping valve 1, the hydraulic oil that has passed through the groove 5 d of the valve body 5 passes through the above-described variable throttle, flows through the annular gap A, and flows to the port 11.

  In the case of this embodiment, since an extremely small annular gap is provided between the outer periphery of the valve portion 5a of the valve body 5 and the inner periphery of the collar 7, the collar 7 and the valve body 5 are caused by a dimensional error. The collar 7 does not come into contact with the valve body 5 even if the shaft center of the shaft 7 is displaced. As a result, the collar 7 and the valve body 5 cannot be assembled, or the collar 7 moves the valve body 5. There is no inconvenience such as obstruction. If the above inconvenience does not occur, the outer periphery of the valve portion 5a may be brought into sliding contact with the inner periphery of the collar 7.

  Further, a spring seat 10 is accommodated in the collar 7 configured as described above. Specifically, the spring seat 10 includes a columnar spring fitting portion 10 a and a flange-shaped spring receiving portion 10 b provided on the outer periphery of the spring fitting portion 10 a and stacked on the bottom portion 7 b of the collar 7. It is configured.

  A coil spring 6 is interposed between the spring seat 10 and the valve body 5. The coil spring 6 is interposed between the spring seat 10 and the valve body 5 in a compressed state and is given an initial load. The valve body 5 is energized by the initial load of the compressed coil spring 6. Is pressed toward the annular valve seat 4 even in a state of being seated on the annular valve seat 4. The spring seat 10 is also loaded by the coil spring 6, so that the spring seat 10 is not separated from the bottom 7 b of the collar 7.

  A spring fitting portion 10a of the spring seat 10 is fitted to the inner circumference of the right end in FIG. 2 that is one end of the coil spring 6, and the inner circumference of the left end in FIG. The spring fitting portion 5c of the valve body 5 is fitted, and the coil spring 6 is positioned in the radial direction. Since the coil spring 6 is positioned in the radial direction by the spring seat 10 and the valve body 5, the coil spring 6 inserted into the collar 7 is prevented from interfering with the collar 7.

  The collar 7 may be formed in a cylindrical shape so that the spring seat 10 is screwed into the collar 7 so that the spring seat 10 can be rotated from the outside of the shock absorber D. In this case, the spring seat The initial load of the coil spring 6 can be adjusted by rotating 10 and moving it forward and backward in the valve hole 3 in the manner of a feed screw.

  In the damping valve 1 configured as described above, the pressure in the rod side chamber R1 acts on the shaft portion 5b of the valve body 5, and the force pushing the valve body 5 biases the valve body 5 of the coil spring 6. When the force exceeds the force, the valve opens, and the fluid that has pushed the valve body 5 away and passed through the groove 5d flows into the valve hole 3 and passes through the variable throttle formed by the valve body 5 and the through hole 7e and passes through the annular gap A. To the port 11, passes through the pipe 9, and moves to the reservoir R.

  As the pressure acting on the distal end side of the valve body 5 increases, the amount of retreat inward of the valve hole 3 that is away from the annular valve seat 4 and becomes the anti-annular valve seat side increases. The valve opening area limited by the annular valve seat 4 increases with the increase, and the flow rate of the fluid passing through the damping valve 1 also increases. In addition, the flow passage area in the variable throttle also increases as the amount of retraction of the valve body 5 from the annular valve seat 4 increases.

  Therefore, in the damping valve 1, when the valve body 5 is separated from the annular valve seat 4 and the damping valve 1 is opened, the hydraulic oil passes through the variable throttle and flows out to the port 11, and the variable throttle is filled with the hydraulic oil. Since resistance is given to the flow, a damping force that suppresses the movement of the valve body 5 in the direction away from the annular valve seat 4 is obtained. This damping force suppresses the vibration of the valve body 5 in the axial direction. The variable throttle minimizes the flow path area at the initial stage of valve opening when the valve body 5 is separated from the annular valve seat 4, and the damping force at the initial stage of valve opening is large, so that the valve body 5 moves backward from the annular valve seat 4. As the amount increases, the damping force decreases. That is, it is possible to suppress the vibration in the axial direction of the valve body 5 by firmly applying a damping force to the valve body 5 at the initial stage of opening the valve body 5 in which the vibration is easily excited. Thereby, the damping valve 1 of the present invention can suppress the oscillation of the valve body 5 and generate a stable damping force in the shock absorber.

  Further, when the damping force acts on the valve body 5, the damping force corresponding to the damping force is overridden by the damping force generated by the shock absorber D, but the retraction amount of the valve body 5 from the annular valve seat 4 increases. Then, since the damping force is reduced, the influence of the damping force on the damping force generated by the shock absorber D can be reduced.

  Furthermore, since the vibration of the valve body 5 can be suppressed only by installing the collar 7, no new processing to the housing provided with the valve hole 3, in this case, no new processing to the rod guide 2 is required. It can be easily and inexpensively incorporated into existing damping valves.

  In addition, like the damping valve 29 in one modification of the embodiment shown in FIG. 4, the valve body 30 is configured with a valve body 31 and a cylindrical wall 32 that is opposed to the through hole 7 e in the radial direction, A variable diaphragm may be formed by the cylindrical wall 32 and the through hole 7e. In addition, about the member which the damping valve 29 shares with the damping valve 1, detailed description is abbreviate | omitted only to attach | subject the same code | symbol in order to avoid duplication of description.

  In this case, the valve body 31 is accommodated in the valve hole 3 so as to be movable in the axial direction, and includes a chamfered portion 31e provided on the outer periphery of the annular valve seat side end and a plurality of notches 31f provided on the outer periphery. 4 is a disc-shaped valve portion 31a that is seated and detached from the valve 4; a cylindrical shaft portion 31b that extends from the left end in FIG. 4 that is the annular valve seat side end of the valve portion 31a; 4, a spring fitting portion 31 c that protrudes to the right in the middle, a groove 31 d provided in the shaft portion 31 b, and a pressure introduction hole 31 h that has an orifice 31 g in the middle from the groove 31 d to the end of the spring fitting portion 31 c. It is configured with. The pressure introduction hole 31 h guides the pressure on the annular valve seat side on which the valve body 31 is the front side to the anti-annular valve seat side on the back side of the valve body 31.

  The cylindrical wall 32 includes an annular laminated portion 32a that is laminated on the valve portion 31a of the valve body 31, and a cylindrical wall portion 32b that rises from the outer periphery of the laminated portion 32a and faces the through hole 7e in the radial direction. ing. The laminated portion 32 a is interposed between the coil spring 6 and the valve body 31. Thus, the laminated portion 32a is pressed against the valve main body 31 by the coil spring 6, and the separation between the valve main body 31 and the cylindrical wall 32 is prevented.

  Further, an annular gap is provided between the wall portion 32b and the collar 7, and the wall portion 32b is opposed to the through hole 7e in the radial direction so that the space on the back side of the valve element 30 is made to have an annular gap A. The flow path communicating with the pressure is restricted, the pressure of the space is prevented from escaping to the port 11, and the space functions as the back pressure chamber P.

  On the other hand, as the valve body 30 is separated from the annular valve seat 4, the cylindrical wall 32 is less overlapped with the through hole 7e in the radial direction, and the opening degree of the through hole 7e is increased. The area is increasing. That is, the cylindrical wall 32 and the through hole 7e constitute a variable diaphragm.

  Accordingly, also with this damping valve 29, when the valve body 30 is separated from the annular valve seat 4 and the damping valve 29 is opened, the hydraulic oil passes through the variable throttle and flows out to the port 11, and the variable throttle becomes the flow of hydraulic oil. Since resistance is given, the damping force which suppresses the movement of the valve body 30 in the direction away from the annular valve seat 4 is obtained. Further, a back pressure chamber P is provided on the back side of the valve body 30, and the pressure on the front side can be reduced and introduced into the back pressure chamber P through the pressure introduction hole 31h. The valve body 30 can be urged toward the annular valve seat 4 side by the pressure of P. As described above, in the damping valve 29 according to the modified example, the valve body 30 can be urged by the pressure of the back pressure chamber P in addition to the above-described damping force. Thus, the effect of suppressing the axial vibration of the valve body 30 is enhanced. Thereby, the damping valve 29 of the present invention can reliably suppress the oscillation of the valve body 30 and generate a stable damping force in the shock absorber.

  Further, by applying the pressure of the back pressure chamber P to the valve body 30 in addition to the damping force, the damping force generated by the shock absorber D is overridden by the damping force corresponding to the damping force and the pressure of the back pressure chamber P. Therefore, the damping force generated by the shock absorber D can be further increased.

  It is possible to eliminate the pressure introduction hole 31h described above. Even if the pressure introduction hole 31h is eliminated, the flow path of the back pressure chamber P is limited by the cylindrical wall 32 and the through hole 7e. The force which suppresses this movement can be exhibited, and the force which suppresses the said movement is added to above-described damping force, and the vibration of the axial direction of the valve body 30 can be suppressed.

  In the above description, the case where the damping valve 1 of the present invention is incorporated in the shock absorber D has been described as an example. However, the present invention can also be applied to a shock absorber other than a double cylinder type, and exhibits the above-described effects. be able to. For example, regardless of whether the cylinder is a single cylinder type or a multiple cylinder type, a shock absorber piston can be used as a housing and a damping valve can be incorporated therein. In this case, one chamber is one of a rod side chamber and a piston side chamber, and the other is The damping valve can generate a damping force in the shock absorber when the shock absorber is extended or contracted, with the other chamber being the other of the rod side chamber and the piston side chamber. In addition, when the shock absorber is a double-tube shock absorber and is set to biflow, the piston side chamber is set as one upstream chamber, the reservoir is set as the other downstream chamber, and a damping valve is incorporated in the base valve portion to You may make it exhibit a damping force to a buffer at the time of contraction.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

1,29 Damping valve 2 Rod guide 3 as housing 3 Valve hole 4 Annular valve seat 5, 30 Valve body 6 Coil spring 7 Collar 7e Through hole 10 Spring seat 11 Port 31 Valve body 31g Orifice 31h Pressure introduction hole 32 Cylindrical wall 32a Laminate part 32b Wall part A Annular gap D Buffer P Back pressure chamber R1 Rod side chamber R as one chamber Rd reservoir as the other chamber

Claims (5)

A housing provided with a valve hole having an annular valve seat in the middle of one chamber of the two chambers formed in the shock absorber, the other chamber being downstream and the other chamber being in communication with the one chamber;
A valve body inserted in the valve hole so as to be movable in the axial direction and seated on and off the annular valve seat;
A port that opens from the side of the valve hole and communicates with the other chamber;
A spring seat accommodated in the valve hole;
In a damping valve provided with a coil spring interposed between the valve body and the spring seat and biasing the valve body toward the annular valve seat side,
Provided with a cylindrical collar which is accommodated in the valve hole and accommodates the valve body inward to form an annular gap leading to the port between the valve hole inner periphery,
The collar includes a through hole that communicates inward with the annular gap and radially opposes the outer periphery of the valve body,
A variable throttle is formed by the through hole and the valve body,
A damping valve according to claim 1, wherein a flow passage area of the variable throttle is increased by separating the valve body from the annular valve seat. 2. The damping valve according to claim 1, wherein the variable throttle has a flow passage area that increases as the pressure in the shock absorber increases. The valve body includes a cylindrical wall that faces radially to the through hole to the outer periphery, to claim 1 or claim 2, characterized in that to form the variable throttle with the said cylindrical wall and the hole The described damping valve. The valve body includes a valve main body and the cylindrical wall, and the cylindrical wall rises from the outer periphery of the laminated portion and is opposed to the through hole in the radial direction. The damping valve according to claim 3 , further comprising: a cylindrical wall portion, wherein the coil spring presses the laminated portion against the valve body to prevent the valve body and the cylindrical wall from being separated. The valve body is provided with a pressure introducing hole for introducing pressure on the annular valve seat side on the front side to the anti-annular valve seat side on the back side with an orifice in the middle, and a back pressure chamber on the back side of the valve body. It formed, The damping valve as described in any one of Claim 1 to 4 characterized by the above-mentioned.

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