JP2013108579A - Damping valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small damping valve at low cost that can perform a precise damping force adjustment, and to provide a shock absorber.SOLUTION: The damping valve V includes a case 20 that has a valve hole H allowing one chamber R1 to communicate with the other chamber R, an annular valve seat 21 that is provided in a midway part of the valve hole H, a valve element 22 that is accommodated within the valve hole H movably in the axial direction and can move near to or away from the valve seat 21, and an actuator (A) that drives the valve element 22 in the axial direction. The shock absorber 1 includes the damping valve V. The shock absorber further includes a valve body 28 wherein the valve element 22 is provided with a flange 28a that comes in slide contact with the inner circumference of the valve hole H, and a shaft 29 that is pivotally supported to the case 20 slidably and projects outside the valve hole H to transmit the thrust force of the actuator (A) to the valve body 28, wherein the front surface side chamber S and the rear surface side chamber B formed within the valve hoe H are communicated with each other through a communication passage C, and the cross sectional area in the sliding part 29a of the shaft 29 is made smaller than that of the flange 28a.

Description

  The present invention relates to improvements in damping valves and shock absorbers.

  A damping valve that enables damping force adjustment is used in a shock absorber such as a front fork of a motorcycle.

  The shock absorber is, for example, a cylinder coupled to the outer tube, a piston that is slidably inserted into the cylinder and divides the cylinder into a compression side chamber and an extension side chamber, and is inserted into the cylinder and has one end thereof. A piston rod connected to the inner tube slidably inserted into the outer tube and having the other end connected to the piston, a passage communicating with the compression side chamber and the extension side chamber, and a midway in the passage And a check valve that allows only the flow from the compression side chamber to the expansion side chamber or, conversely, allows only the flow from the expansion side chamber to the compression side chamber. The damping valve used in this shock absorber is fixed to the annular valve seat provided in the middle of the passage, the needle-shaped valve body that is attached to and detached from the valve seat, and the other end side of the piston rod, and the valve body (See, for example, Patent Document 1).

  In this shock absorber, when the piston is extended, the piston valve provided on the piston resists the flow of the hydraulic oil and exerts a damping force, and when contracted, the base valve provided at the end of the cylinder flows out from the cylinder to the reservoir. It exerts a damping force by giving resistance to the flow of hydraulic oil.

  In addition, in this shock absorber, hydraulic fluid flows through the passage only during expansion or contraction due to the action of the above-described check valve, and a resistance is given to the flow of hydraulic fluid by the valve body, thereby buffering. The damping valve cooperates to exert a damping force when either the device is extended or contracted, and the other damping valve adjusts the flow path area by driving the valve body with a motor. By doing so, the damping force of this shock absorber is made variable.

  In other words, the damping valve exhibits a damping function only when the shock absorber is extended or contracted. However, a front fork that suspends a wheel of a two-wheeled vehicle usually suspends a pair of wheels on the left and right, so one front fork The shock absorber valve body built in the valve is made to exhibit a damping function when extended, and the shock absorber needle valve built in the other front fork is made to perform the damping function when contracted. As a whole of the fork, the damping force on the extension side and the contraction side can be adjusted.

JP 2008-14431 A

  In the above-described shock absorber, the flow of the hydraulic oil passing through the damping valve is always one-way and becomes a stable flow. Therefore, there is an advantage that the damping force generated in the shock absorber can be accurately adjusted.

  By the way, the valve body in the damping valve receives the high pressure of the chamber compressed by the expansion and contraction of the shock absorber. For this reason, the stepping motor must overcome the pressure and drive the valve body. However, when the torque is insufficient, it is difficult to accurately adjust the damping force.

  In order to solve this problem and to accurately adjust the damping force even when the shock absorber is in expansion / contraction operation, it is conceivable to use a stepping motor that can output a large torque, but the stepping motor can output a large torque. If it tries to do so, the stepping motor will become large and the cost will become high, and the economy and the mountability to the vehicle will be sacrificed.

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a damping valve that is low-cost, small in size, and capable of accurately adjusting damping force. It is another object of the present invention to provide a shock absorber capable of accurately adjusting the damping force without sacrificing the mountability on a vehicle at the same low cost.

  In order to achieve the above-described object, the problem-solving means of the present invention includes: a case having a valve hole communicating with one chamber and the other chamber; and the one chamber and the other chamber in the middle of the valve hole. An annular valve seat provided therebetween, a valve body that is accommodated in the valve hole so as to be movable in the axial direction and can be moved to and away from the valve seat, and provided outside the case to drive the valve body in the axial direction In the damping valve including the actuator, the valve body includes a valve body including a flange slidingly contacting the inner periphery of the valve hole, and a valve head extending from the flange and seating on the valve seat at the tip. A shaft that is slidably supported by the case and protrudes out of the valve hole and transmits the thrust of the actuator to the valve body, and the valve body includes the valve seat and the flange in the valve hole. Front side chamber leading to the other chamber between and the flange The front side chamber and the back side chamber are divided into a back side chamber on the side opposite to the valve seat, and a range in which the shaft is in sliding contact with the case is set as a sliding portion, and a cross sectional area of the sliding portion is smaller than a cross sectional area of the flange. Are connected by a communication passage.

  Another problem-solving means of the present invention includes a cylinder, a piston that is slidably inserted into the cylinder and divides the cylinder into a compression side chamber and an extension side chamber, and is inserted into the cylinder. A piston rod connected to the piston; a reservoir provided outside the cylinder; a flow path communicating one of the pressure side chamber and the extension side chamber to the reservoir; and the pressure side chamber disposed in the middle of the flow path; A case provided with a valve hole communicating with one of the extension side chambers and the reservoir; an annular valve seat provided between the one chamber and the other chamber in the middle of the valve hole; and the valve In the shock absorber provided with a valve body that is accommodated in the hole so as to be movable in the axial direction and can be moved closer to the valve seat, and an actuator that is provided outside the case and drives the valve body in the axial direction. The body is the inner circumference of the valve hole A valve body having a flange that is in sliding contact and a valve head that extends from the flange and is attached to and detached from the valve seat at the tip, and is slidably supported by the case and protrudes out of the valve hole so as to protrude from the valve body. A shaft that transmits the thrust of the actuator, and a front side chamber in which the inside of the valve hole leads to the other chamber between the valve seat and the flange by the valve body, and a rear side chamber on the side opposite to the valve seat from the flange. The range of the shaft that is in sliding contact with the case is defined as a sliding portion, the cross-sectional area of the sliding portion is made smaller than the cross-sectional area of the flange, and the front side chamber and the back side chamber are communicated with each other by a communication passage. It is characterized by that.

  Since the damping valve or the shock absorber is configured as described above, the same pressure acts not only from the front side chamber side but also from the back side chamber side to the valve body. A force having a value obtained by multiplying the cross-sectional area by the pressure acts in a direction away from the valve seat. Therefore, the force which presses a valve body in the direction away from a valve seat with the pressure which acts on a valve body becomes small compared with the conventional damping valve.

  Therefore, in the damping valve or the shock absorber according to the present invention, when the valve body is driven in the direction of approaching the valve seat, the force that suppresses the approach of the valve body to the valve seat is small due to the pressure acting on the valve body. Therefore, even when the thrust of the actuator is small, the damping force can be adjusted accurately.

  According to the damping valve and the shock absorber of the present invention, it is not necessary to make the actuator have a large output, and accurate damping force adjustment can be performed while avoiding an increase in size of the actuator. Further, according to the shock absorber of the present invention, a small actuator can be used at a low cost, so that the mounting property on the vehicle is not impaired.

It is sectional drawing of the shock absorber which mounts the damping valve in one embodiment. It is an expanded sectional view of the damping valve in one embodiment. It is a top view of the valve body of the damping valve in one embodiment.

  The present invention will be described below based on the embodiments shown in the drawings. As shown in FIG. 1, a shock absorber 1 according to an embodiment includes a cylinder 2 and a piston 3 that is slidably inserted into the cylinder 2 and divides the cylinder 2 into a compression side chamber R2 and an extension side chamber R1. The piston rod 4 inserted into the cylinder 2 and connected to the piston 3, the reservoir R provided outside the cylinder 2, the flow path 5 communicating the extension side chamber R 1 and the reservoir R, and the middle of the flow path 5 Is provided with a damping valve V.

  Hereinafter, each part will be described in detail. In this embodiment, the shock absorber 1 is connected to a vehicle body side tube 10 in which the piston rod 4 is connected to a vehicle body (not shown) of a saddle-ride type vehicle such as a two-wheeled vehicle, and to a vehicle body side. It is accommodated in a front fork F constituted by an axle side tube 11 slidably inserted into the tube 10. More specifically, the shock absorber 1 is connected between the vehicle body side tube 10 and the axle side tube 11 by connecting the piston rod 4 to the vehicle body side tube 10 and connecting the cylinder 2 to the axle side tube 11. The vehicle is housed in a front fork F closed by a vehicle body side tube 10 and an axle side tube 11. In the present embodiment, the front fork F is an inverted front fork in which the axle side tube 11 is inserted into the vehicle body side tube 10, but on the contrary, the vehicle body side tube 10 is connected to the axle side tube 11. It may be an upright front fork to be inserted.

  A suspension spring 12 is interposed between the piston rod 4 and the cylinder 2 of the shock absorber 1, and the suspension spring 12 connects the vehicle body side tube 10 and the axle side tube 11 via the shock absorber 1. The urging force is exerted in the direction of separating, that is, the direction of extending the front fork F, and the suspension spring 12 elastically supports the vehicle body of the saddle-ride type vehicle not shown. A reservoir R is formed outside the cylinder 2 by using a closed space formed by the vehicle body side tube 10 and the axle side tube 11.

  In addition to the above-described configuration, the shock absorber 1 built in the front fork F is provided in the piston 3 to connect the extension side chamber R1 and the pressure side chamber R2 and to provide resistance to the flow of fluid passing therethrough. A damping passage 13, a pressure-side damping passage 15 provided at the lower end of the cylinder 2 to provide resistance to the flow of fluid from the pressure-side chamber R2 to the reservoir R, and a suction passage that allows only the flow of fluid from the reservoir R to the pressure-side chamber The expansion side chamber R1 and the pressure side chamber R2 are filled with a liquid such as hydraulic oil as a fluid, and the reservoir R is filled with a liquid and a gas.

  In more detail, the cylinder 2 is being fixed to the bottom part of the axle side tube 11 formed in the bottomed cylinder shape via the bottom member 14 fitted by the lower end. A rod guide 17 is provided at the upper end of the cylinder 2 to support the piston rod 4 so as to be slidable. The piston rod 4 includes a piston rod body 4a that is cylindrical and has a hollow portion 4b, and a piston coupling portion 4c that is fixed to the lower end of the piston rod body 4a in FIG. The upper end in FIG. 1 is fixed to the upper end of the vehicle body side tube 10 via the housing 9 that houses the damping valve V. The piston connecting portion 4c includes a communication passage 4d that allows the hollow portion 4b and the extension side chamber R1 to communicate with each other, and a check valve that is provided in the middle of the communication passage 4d and allows only a liquid flow from the extension side chamber R1 toward the hollow portion 4b. 4e, and the annular piston 3 is fixed to the lower end in FIG.

  The suspension spring 12 is interposed between the rod guide 17 and a cylindrical spring receiver 18 provided on the outer periphery of the housing 9, and the shock absorber 1 is urged in the extending direction, whereby the front fork F also extends. It is designed to be biased in the direction.

  The piston 3 is fixed to the lower end in FIG. 1 of the piston rod 4, and the damping passage 13 provided in the piston 3 is provided in the middle of the passage 13a and the passage 13a that connects the extension side chamber R1 and the pressure side chamber R2. A damping valve 13b is provided to provide resistance to the flow of liquid passing therethrough. In this case, the damping valve 13b is a throttle valve or the like, and the damping passage 13 has a bidirectional flow of the liquid flowing from the expansion side chamber R1 to the compression side chamber R2 and the flow of the liquid from the compression side chamber R2 to the expansion side chamber R1. Although the flow is allowed, two or more passages are provided, and a damping valve that allows only the flow of the liquid from the extension side chamber R1 to the pressure side chamber R2 is provided in a part of the passages, and the pressure side is provided in the other passages. A damping valve that allows only the flow of liquid from the chamber R2 toward the extension side chamber R1 may be provided.

  The pressure-side damping passage 15 formed in the bottom member 14 resists the flow of the liquid passing through the passage 15a that connects the pressure-side chamber R2 and the reservoir R, and allowing only the flow of the liquid from the pressure-side chamber R2 to the reservoir R. And a one-way passage allowing only the flow of liquid from the pressure side chamber R2 to the reservoir R. On the other hand, the suction passage 16 formed in the bottom member 14 includes a passage 16a that connects the pressure side chamber R2 and the reservoir R, and a check valve 16b that allows only the flow of liquid from the reservoir R to the pressure side chamber R2. This is a one-way passage that allows only the flow of liquid from the reservoir R to the pressure-side chamber R2 in the opposite direction to the pressure-side attenuation passage 15.

  Next, the damping valve V will be described. As described above, the damping valve V is provided in the middle of the flow path 5 that allows only the liquid to pass from the extension side chamber R1 to the reservoir R through the extension side chamber R1 and the reservoir R. In the embodiment, a housing 9 provided at the upper end of the piston rod 4 and a valve hole H which is accommodated and fixed in the housing 9 and communicates with an extension side chamber R1 serving as one chamber and a reservoir R serving as the other chamber are provided. A case 20, an annular valve seat 21 provided in the middle of the valve hole H and between the expansion side chamber R 1 and the reservoir R, and the valve seat 21 accommodated in the valve hole H so as to be movable in the axial direction. And an actuator A that is provided outside the case 20 and drives the valve body 22 in the axial direction.

  As shown in FIGS. 1 and 2, the housing 9 has a cylindrical shape. In this case, the small diameter portion 9a at the lower end in the drawing, the large diameter portion 9b at the upper end in the drawing, the small diameter portion 9a, and the large diameter portion. And a medium diameter portion 9c between the large diameter portion 9b and the small diameter portion 9b between the small diameter portion 9a and the large diameter portion 9b. . Further, in the small diameter portion 9a, a screw portion 9d into which the upper end of the piston rod 4 at the lower end in the figure is screwed, and an inner diameter above the screw portion 9d is made larger than the inner diameter of the screw portion 9d. A portion 9e is provided. Further, the inner diameter of the medium diameter portion 9c is set to be larger than the inner diameter of the small diameter portion 9a, and the inner diameter of the large diameter portion 9b is enlarged from the middle to be larger than the inner diameter of the medium diameter portion 9c. ing. Further, a vertical groove 9f is provided along the axial direction on the outer periphery of the small diameter portion 9a of the valve housing 9, and the vertical groove 9f is provided in the valve housing 9 in the small diameter portion 9a from the step portion 9e. Also, a lateral hole 9g communicating with the upper side is provided.

  In this embodiment, the case 20 includes a bottomed cylindrical sheet member 23 and a guide member 24 that is cylindrical and is fitted inwardly from the opening end side. Yes.

  The sheet member 23 has a bottomed cylindrical shape as described above, and includes a bottom portion 23a and a cylindrical portion 23b. The bottom 23a is provided with a high-pressure side port 23c, and the periphery of the high-pressure side port 23c inside the seat member is the above-described annular valve seat 21. Further, near the bottom 23a of the cylindrical portion 23b, a low-pressure side port 23d that passes through the inside and the outside of the sheet member 23 is provided.

  Further, the guide member 24 is cylindrical as described above, and an annular bearing portion 24a that protrudes toward the inner peripheral side is provided inside the intermediate portion. An annular seal member 25 is stacked below the bearing portion 24a in FIG. Further, a step portion 24b is provided on the lower side in FIG. 2 with respect to the bearing portion 24a of the guide member 24, and an annular stopper 26 for preventing the sealing member 25 from coming off is laminated on the step portion 24b. ing. Further, an annular groove 24c and a screw portion 24d are provided on the outer periphery of the guide member 24, and a seal ring 27 is mounted in the annular groove 24c.

  The case 20 is formed by fitting the seat member 23 configured in this way to the inside of the guide member 24 from the opening end side, and the valve is formed in the space created between the seat member 23 and the guide member 24. Hole H is formed. Note that the axial length of the guide member 24 below the bearing portion 24a is taken into consideration so as not to block the low-pressure side port 23d of the seat member 23. And while accommodating this case 20 in the inside diameter part 9c of the housing 9, the screw part 24d provided in the outer periphery of the guide member 24 is screwed to the screw part (not shown) formed in the inner periphery of the inside diameter part 9c. When worn, the case 20 is fixed to the housing 9. Since the bottom 23a of the sheet member 23 abuts on the step 9e of the housing 9 and is sandwiched between the step 9e of the housing 9 and the guide member 24, the sheet member 23 is loosely fitted to the guide member 24. However, the sheet member 23 can be fixed in the housing 9. In this case, the cylindrical portion 23 b of the sheet member 23 is press-fitted into the guide member 24.

  As described above, when the case 20 is fixed to the housing 9, the bottom 23 a comes into contact with the stepped portion 9 e as described above, and the inside of the housing 9 is divided into the inside of the small diameter portion 9 a and the inside of the medium diameter portion 9 c by the case 20. It is done. And the high pressure side port 23c provided in the bottom 23a of the seat member 23 in the case 20 faces the small diameter portion 9a, and the valve hole H passes through the high pressure side port 23c and the hollow portion 4b provided in the piston rod 4. It communicates with the extension side chamber R1. Further, the low pressure side port 23d provided in the cylindrical portion 23b of the seat member 23 in the case 20 faces the inside diameter portion 9c, and the valve hole H is connected to the low pressure side port 23d and the lateral hole 9g provided in the housing 9. To the reservoir R.

  Accordingly, the flow path 5 includes a hollow portion 4b provided in the piston rod 4, a communication passage 4d, a valve provided in the housing 20 connected to the upper end of the piston rod 4 in FIG. A hole H and a lateral hole 9g communicating with the reservoir R inside the housing 9 are configured to communicate the extension side chamber R1 and the reservoir R, and by a check valve 4e provided in the middle of the communication passage 4d. Only the passage of liquid from the extension side chamber R1 to the reservoir R is allowed. The check valve for setting the flow path 5 to be one-way may not be provided in the piston connecting portion 4c but may be provided in another location. Specifically, for example, in the hollow portion 4b of the piston rod body 4a. It may be provided at the opening end of the hollow portion 4b at the upper end in FIG. 1 of the piston rod body 4a.

  On the other hand, the valve body 22 includes a flange 28a slidably in contact with the inner periphery of the valve hole H and a conical valve head 28b extending from the flange 28a toward the valve seat side and seating on the valve seat 21 at the tip. 28 and a shaft 29 that is slidably inserted into the bearing portion 24a and transmits the thrust of the actuator A to the valve body 28. As shown in FIG. 3, the valve body 28 has four notches 28d cut off from the outer periphery of the flange 28a. Between the notches 28d and the inner wall of the valve hole H, in this case, the notches 28d and the seat are provided. A communication path C is formed between the cylindrical portion 23 b of the member 23. One end of the shaft 29 is integrated with the valve body 28, and the other end is inserted into the inner periphery of the bearing portion 24 a and protrudes out of the valve hole H. The shape of the valve head 28b is arbitrary and is not limited to the conical shape described above.

  The valve body 22 is axially oriented in the seat member 23 while the valve head 28b faces the valve seat 21 and the outer periphery of the flange 28a is in sliding contact with the inner periphery of the cylindrical portion 23b of the seat member 23 in FIG. It is inserted to be movable in the direction. Therefore, the valve body 22 is movably accommodated in a valve hole H formed by the seat member 23 and the guide member 24 constituting the case 20. As described above, the valve body 22 can stroke in the axial direction within the valve hole H, but the flange 28a is always on the side opposite to the valve seat than the low-pressure side port 23d provided in the cylindrical portion 23b of the seat member 23. It is supposed to be located. Therefore, the inside of the valve hole H is partitioned by the valve main body 28 into a front side chamber S leading to the reservoir R as the other chamber between the valve seat 21 and the flange 28a and a back side chamber B on the side opposite to the valve seat from the flange 28a. The

  The front side chamber S and the back side chamber B are communicated with each other through a communication passage C formed on the outer periphery of the flange 28a so that the pressure in the front side chamber S is propagated to the back side chamber B. The communication passage C is formed by providing a notch 28d in the flange 28a of the valve body 28. Therefore, the communication passage C can be formed by performing simple processing on the valve body 22, but the front side chamber S and the back side chamber B are formed. Since it should just communicate, it is not limited to the said structure. Therefore, for example, a long hole or notch that functions as a communication passage C is provided in the cylindrical portion 23b of the seat member 23 along the axial direction so that the front side chamber S and the back side chamber B communicate with each other through the long hole. Even if 22 strokes within the valve hole H, the communication between the front side chamber S and the rear side chamber B may not be cut off by the flange 28a.

  Further, a coil spring 30 as an elastic body is interposed between the flange 28 a and the bottom 23 a of the seat member 23 constituting the case 20, and the valve body 22 is moved from the valve seat 21 by the coil spring 30. It is energized away. In energizing the valve body 22, in addition to the coil spring 30, it is also possible to use an elastic body capable of exerting an energizing force such as a disc spring, a wave washer or rubber.

  Further, when the valve body 22 strokes in the valve hole H, the shaft 29 also strokes in the axial direction with respect to the bearing portion 24a. At this stroke, the shaft 29 is placed on the inner periphery of the bearing portion 24a provided in the case 20. If the sliding contact range is a sliding contact portion 29a (the shaded portion in FIG. 2), the cross sectional area of the sliding contact portion 29a is smaller than the cross sectional area of the flange 28a. Here, the cross section is a cross section obtained by cutting in a direction perpendicular to the axial direction (left and right direction in FIG. 2), and the area of this cross section is defined as a cross section.

  The outer peripheral shape of the shaft 29 and the outer peripheral shape of the flange 28a are both circular if the notch 28d is ignored. In this case, the outer diameter of the shaft 29 is smaller than the outer diameter of the flange 28a. The outer peripheral shape of the shaft 29 and the outer peripheral shape of the flange 28a are not limited to this. Further, the outer diameter of the shaft 29 is equally cylindrical over the entire length in the axial direction, but the outer diameter may be changed. That is, it is possible to use the shaft 29 whose cross-sectional area is not constant over the entire axial length.

  In this case, the actuator A includes an actuator body 31 and a movable portion 32 that can move in the axial direction with respect to the actuator body 31. The actuator body 31 includes, for example, a rotary motor, and a motion conversion mechanism that is connected to a rotor of the motor and includes a rotary member and a linear motion member that exhibits an axial linear motion by the rotation of the rotary member. May be. As the motion conversion mechanism, for example, a mechanism such as a feed screw mechanism or a rack and pinion can be adopted. The actuator A may be a linear motor or a solenoid. In this case, the stator may be the actuator body 31 and the mover may be the movable part 32.

  Then, with the movable part 32 facing the case 20 side, the actuator body 31 is accommodated in the large-diameter part 9b of the housing 9, and the ring nut 33 is screwed to the inner periphery of the open end of the large-diameter part 9b of the housing 9. Thus, the actuator main body 31 is sandwiched between the ring nut 33 and the housing 9 and fixed in the large-diameter portion 9 b of the housing 9.

  Even if the actuator body 31 is fixed to the housing 9 as described above, the movable portion 32 is not fixed to the housing 9 at all, and can move in the axial direction within the housing 9. Further, the distal end of the movable portion 32 is in contact with the other end of the shaft 29, and when the actuator A applies a thrust to move the movable portion 32 toward the valve body 22, the distal end of the movable portion 32 is directed to the valve body 28 via the shaft 29. The thrust is transmitted and the valve body 22 can be driven toward the valve seat 21. In this embodiment, since the coil spring 30 is provided as an elastic body that biases the valve body 22 away from the valve seat 21, the movable portion 32 and the shaft 29 are not fixedly connected. In both cases, the contact between the movable portion 32 and the shaft 29 is maintained, and the thrust of the actuator A can be transmitted to the valve body 22. In this case, the shaft 29 and the valve body 28 are separated from each other. It may be configured as an independent part. In addition to the shaft 29 and the valve body 28 being integrated as in the present embodiment, when the shaft 29 is fixedly connected to the movable portion 32, an elastic body that biases the valve body 22 is provided. Since the valve body 22 can be driven in the axial direction by only the actuator A and moved away from the valve seat 21 without being required, in such a case, the elastic body can be eliminated.

  When the actuator 22 is driven to push down the valve body 22 toward the valve seat 21, the valve head 22 b of the valve body 22 can be seated on the valve seat 21, and thus the valve head 22 b is seated on the valve seat 21. Then, the flow path 5 is interrupted. When the movable part 32 in the actuator A is driven to the actuator main body 31 side from this state, the valve body 22 is pushed up by the coil spring 30, so that the valve body 22 moves away from the valve seat 21, and the valve head 22b and the valve A gap is formed between the seat 21 and the flow path 5 is opened. That is, by driving the actuator A, the valve body 22 can be advanced and retracted with respect to the valve seat 21 and the flow path area of the flow path 5 can be changed. That is, the flow path area of the flow path 5 can be changed depending on the positional relationship between the valve body 22 and the valve seat 21, and when the valve body 22 is farthest from the valve seat 21, the flow path area of the flow path 5 is maximized and the valve body 22 When seated on the seat 21, that is, when the valve head 22 b comes into contact with the valve seat 21, the flow path 5 is completely blocked and the flow path area becomes zero. When the flow path 5 is in an open state, the extension side chamber R1 and the reservoir R are in communication with each other, and when the shock absorber 1 exhibits an expansion operation, the liquid passes through the flow path 5 and is discharged to the reservoir R. A resistance is given to the flow of the liquid according to the flow path area of the flow path 5.

  As a procedure for assembling each member of the damping valve V configured as described above, for example, the valve body 22 is inserted into the seat member 23 together with the coil spring 30, and the stopper 26 and the seal member 25 are attached to the shaft 29. The sheet member 23 is press-fitted into the guide member 24 from the opening end side. Then, since the case 20 and the valve body 22 are assembled into a cartridge, this may be screwed to the housing 9 and the actuator A may be fixed to the housing 9 with the ring nut 33. As described above, since the case 20 and the valve body 22 are formed into a cartridge, the assembly to the shock absorber 1 is facilitated, and a plurality of cartridges having different diameters of the high-pressure side port 23c and the shape of the valve head 28b of the valve body 22 are prepared. Thus, if the cartridge is replaced, the damping force characteristic can be easily changed. Note that, when the seat member 23 is kept in the fitting without being press-fitted into the guide member 24, the valve body 22 and the seat member 23 can be independently replaced. This can be done by exchanging 22 or the sheet member 23.

  In this embodiment, since the valve body 28 and the shaft 29 constituting the valve body 22 are integrated, the stopper 26 and the seal member 25 are assembled to the shaft 29 in advance. Since alignment with respect to the guide member 24 becomes easy, the assembly of the sheet member 23 to the guide member 24 becomes very simple, and there is no fear that the shaft 29 falls off after the valve body 22 is made into a cartridge in the case 20.

  In addition, in case 20 in this Embodiment, although the structure which provides the high pressure side port 23c, the low pressure side port 23d, and the valve seat 21 in the seat member 23 is employ | adopted, it is not limited to this structure. For example, only the high pressure side port 23 c and the valve seat 21 are provided on the seat member 23, and the low pressure side port 23 d is provided on the guide member 24 side, and the outer periphery of the flange 28 a of the valve body 22 is slidably contacted with the inner periphery of the guide member 24. Such a structure can also be adopted. Even in this case, if the seat member 23 and the guide member 24 are fixedly fastened by press-fitting, screwing or the like, the case 20 and the valve body 22 are formed into a cartridge, and the above-described advantages are obtained. You can enjoy it.

  Next, operations of the shock absorber 1 and the damping valve V configured as described above will be described. In the case of the shock absorber 1, when the piston 3 moves upward in FIG. 1 with respect to the cylinder 2, the damping passage 13 resists the flow of the liquid moving from the expansion side chamber R 1 compressed by the piston 3 to the pressure side chamber R 2. In addition, a damping valve V provides resistance to the flow of liquid from the extension side chamber R1 to the reservoir R. That is, in this embodiment, the shock absorber 1 exerts an extension side damping force by the damping passage 13 and the damping valve V during extension. Note that liquid is supplied from the reservoir R through the suction passage 16 provided in the bottom member 14 to the pressure side chamber R2 that expands when extended, and the piston rod 4 retreats from the cylinder 2 when the shock absorber 1 extends. The change in the volume in the cylinder 2 occurring at is compensated.

  On the other hand, when the piston 3 is contracted to move downward in FIG. 1 with respect to the cylinder 2, a resistance is given to the flow of the liquid moving from the pressure side chamber R2 compressed by the piston 3 to the extension side chamber R1 by the attenuation passage 13, and The liquid corresponding to the volume reduction in the cylinder 2 caused by the piston rod 4 entering the cylinder 2 is discharged to the reservoir R through the compression side damping passage 15 of the bottom member 14 to compensate for the volume change in the cylinder 2. Therefore, the pressure side damping passage 15 also provides resistance to the liquid flow. Accordingly, when the shock absorber 1 contracts, the damping passage 13 and the pressure side damping passage 15 exert a compression side damping force. In this case, the liquid is prevented from flowing into the flow path 5, so the damping valve V is connected to the pressure side. It is not involved in the generation of damping force.

  In the damping valve V, since the flow passage area of the flow passage 5 can be made variable by driving the valve body 22, the shock absorber 1 can adjust the extension side damping force at the time of extension. It is like that.

  When adjusting the damping force, when the valve body 22 is separated from the valve seat 21 and the flow path 5 is in an open state, the valve body 22 has an opening from the expansion side chamber R1 when the shock absorber 1 is being extended. When a high pressure is applied and the shock absorber 1 contracts, the axle tube 11 enters the vehicle body side tube 10, so that the volume of the reservoir R decreases and the pressure in the reservoir R rises. It acts on the valve body 22.

  Specifically, these pressures propagate within the valve hole H and to the front side chamber S, but also propagate to the back side chamber B via the communication passage C. The pressure propagated to the front side chamber S acts to push up the valve body 22 upward in FIG. 2, that is, to push it away from the valve seat 21, and the magnitude of the force is the flange 28 a of the valve body 22. The cross-sectional area is multiplied by the above pressure. On the other hand, the pressure propagated to the rear side chamber B acts to push the valve body 22 downward in FIG. 2, that is, to push it down toward the valve seat 21, and the magnitude of the force is the flange of the valve body 22. This value is obtained by multiplying the value obtained by subtracting the cross-sectional area of the sliding contact portion 29a of the shaft 29 from the cross-sectional area of 28a.

  Thus, since the same pressure acts on the valve body 22 not only from the front side chamber S side but also from the back side chamber B side, as a result, the valve body 22 is subtracted from the sliding contact portion 29a of the shaft 29. A force having a value obtained by multiplying the cross-sectional area by the pressure acts in a direction away from the valve seat 21.

  Therefore, the force which presses the valve body 22 in the direction away from the valve seat 21 due to the pressure acting on the valve body 22 is smaller than that of the conventional damping valve.

  Therefore, in the damping valve V according to the present invention, the valve body 22 is driven in a direction to approach the valve seat 21, that is, when the flow passage area in the flow passage 5 is reduced, the pressure acting on the valve body 22 is reduced. Since the force that suppresses the approach of the valve body 22 to the valve seat 21 is small, the damping force can be adjusted accurately even if the thrust of the actuator A is small.

  Thus, it is not necessary to make the actuator A have a large output, and accurate damping force adjustment can be performed while avoiding an increase in the size of the actuator A. And since the actuator A which is small and low-cost can be used, the mounting property to a vehicle is not impaired.

  That is, according to the damping valve V of the present invention, the damping force can be accurately adjusted at a low cost and with a small size. According to the shock absorber 1 of the present invention, the actuator A has a small size. Since it can be used, in addition to the above-described effects, it is possible to achieve an effect that the mountability to the vehicle is not impaired.

  Further, the damping valve V of the present invention includes the housing 9 in which the case 20 and the actuator A are detachably accommodated, so that the case 20 and the actuator A can be easily replaced, and the damping force characteristic can be improved. Changes and maintenance can be performed easily.

  The case 20 includes a seat member 23 provided with a valve seat 21 and a guide member 24 that slidably supports a shaft 29. The seat member 23 and the guide member 24 are fixedly fastened and the valve hole H Since the valve body 22 is accommodated in the valve hole H, the case 20 and the valve body 22 can be assembled into a cartridge, and the assembly of the damping valve V is simplified. Further, the damping force characteristic can be changed more easily by simply changing the cartridge of the case 20 and the valve body 22.

  Specifically, in the damping valve V of the present embodiment, the bottom portion 23a in which the valve seat 21 is formed around the high-pressure side port 23c where the case 20 communicates with the extension side chamber R1 as one chamber, and the flange 28b. The bottomed cylindrical sheet member 23 having a cylindrical portion 23b provided with a low-pressure side port 23d communicating with the reservoir R serving as the other chamber, and a cylindrical shape that supports the shaft 29 inwardly. And a guide member 24 into which the seat member 23 is fitted from the opening end side, and a valve hole H is formed by the seat member 23 and the guide member 24 so that the valve body is Since it is accommodated in the valve hole H, the case 20 and the valve body 22 are assembled into a cartridge, and the assembly of the damping valve V and the change of the damping force characteristic are simplified.

  In the damping valve V of the present embodiment, an elastic body is provided between the flange 28a and the bottom portion 23a of the seat member 23 to urge the valve body 22 away from the valve seat 21. Since the actuator A and the valve body 22 do not need to be fixedly connected, it is not necessary to align the actuator A and the valve body 22 with high accuracy, the processing cost is reduced, and the damping valve V is strictly controlled. Even if the assembly is performed without proper positioning, the damping force can be adjusted accurately.

  Further, in the damping valve V of the present embodiment, an annular seal member 25 slidably contacting the outer periphery of the sliding portion 29a of the shaft 29 is laminated on the valve hole H side of the bearing portion 24a of the guide member 24, and the guide Since the annular stopper 26 that prevents the seal member 25 from coming off is sandwiched between the bearing portion 24 a of the member 24 and the seat member 23, the seal member 25 is also cartridged together with the valve body 22 in the case 20. Assembly of V becomes even easier.

  Although the description of the embodiment of the present invention has been completed, the damping valve V is configured to allow the passage of the fluid only when the shock absorber 1 is extended. Since it functions as a damping force generating element that generates the expansion side damping force of the shock absorber 1, the expansion side damping force of the shock absorber 1 can be adjusted, but only when the shock absorber 1 contracts, the flow path 5. May be set so as to allow the passage of fluid, and function as a damping force generating element that generates the compression side damping force of the shock absorber 1 to adjust the compression side damping force. If the pressure side chamber R2 communicates with the hollow portion 4b instead of the expansion side chamber R1 in the communication passage 4d provided in the piston connecting portion 4c, the damping valve V can adjust the pressure side damping force. In other words, the damping valve V may be either one of the expansion side chamber R1 and the pressure side chamber R2 and, conversely, the reservoir R as one chamber and the other chamber as either the expansion side chamber R1 or the pressure side chamber R2. Alternatively, the damping force may be adjusted by both expansion and contraction of the shock absorber 1 by using the one chamber and the other chamber as the expansion side chamber R1 and the compression side chamber R2.

  Further, a housing 9 that accommodates the valve body 22, the case 20, and the actuator A is provided at the tip of the piston rod 4, and the flow path 5 penetrates the piston rod 4 and is connected to the compression side chamber R2 or the expansion side chamber R1 in the shock absorber 1. The housing 9 is connected to the reservoir R provided outside the cylinder 2 and connected to the vehicle body of the saddle-ride type vehicle, and the wheel-side tube 11 connected to the wheels of the saddle-ride type vehicle. The piston rod 4 in the shock absorber 1 is connected to the vehicle body side tube 10 and the cylinder 2 is connected to the axle side tube 11, and the actuator A is fixed to the housing 9 and protruded from the vehicle body side tube 10. Therefore, the valve body 22 and the actuator A can be arranged close to each other so that the valve body 22 can be driven without using a long control rod, and the number of parts can be reduced. With the damping force control can be improved because it more accurately drive the valve body 22 with attained, feeding is facilitated convenience and versatility of external to the actuator A can be improved.

  Further, the shock absorber 1 may be configured such that when the damping valve V exhibits a damping force when the shock absorber 1 is extended, the damping valve V is configured to exhibit a damping force only when the shock absorber 1 is extended. In the case where the damping force is exhibited during the contraction, a configuration that exhibits the damping force only during the contraction may be employed.

  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.

  The present invention can be used for a shock absorber.

DESCRIPTION OF SYMBOLS 1 Buffer 2 Cylinder 3 Piston 4 Piston rod 5 Flow path 9 Housing 20 Case 21 Valve seat 22 Valve body 23 Seat member 23a Bottom part 23b Tube part 23c High pressure side port 23d Low pressure side port 24 Guide member 24a Bearing part 25 Seal member 26 Stopper 28 Valve body 28a Flange 28b Valve head 29 Shaft 29a Sliding part 30 Coil spring A as an elastic body Actuator B Rear side chamber C Connection passage H Valve hole R Reservoir R1 as the other chamber Extension side chamber R2 Pressure side chamber S Front side Side chamber V damping valve

Claims (9)

A case having a valve hole communicating with the one chamber and the other chamber; an annular valve seat provided between the one chamber and the other chamber in the middle of the valve hole; and a shaft in the valve hole In a damping valve comprising a valve body that is movably accommodated in a direction and can be moved to and away from the valve seat, and an actuator that is provided outside the case and drives the valve body in the axial direction.
The valve body is slidably supported by the case and a valve body having a flange slidably in contact with the inner periphery of the valve hole, a valve head extending from the flange and seating on the valve seat at the tip. A shaft that protrudes out of the valve hole and transmits the thrust of the actuator to the valve body,
The inside of the valve hole is partitioned by the valve body into a front side chamber that leads to the other chamber between the valve seat and the flange, and a back side chamber on the side opposite to the valve seat from the flange,
The range of sliding contact with the case of the shaft as a sliding portion, the cross-sectional area of the sliding portion is smaller than the cross-sectional area of the flange,
A damping valve, wherein the front side chamber and the back side chamber communicate with each other through a communication passage. The damping valve according to claim 1, further comprising a housing that detachably accommodates the case and the actuator. The case includes a seat member provided with the valve seat and a guide member that slidably supports the shaft, and the seat member and the guide member are fixedly fastened to form the valve hole. The damping valve according to claim 1 or 2, wherein the valve body is accommodated in the valve hole. The case above
A bottomed cylindrical seat member having a bottom portion where the valve seat is formed around a high pressure side port leading to one chamber, and a cylindrical portion having a low pressure side port communicating with the outer periphery of the flange and leading to the other chamber And a guide member that is cylindrical and includes a bearing portion that supports the shaft inwardly, and in which the sheet member is press-fitted from the open end side, and the sheet member and the guide member The damping valve according to any one of claims 1 to 3, wherein the valve hole is formed and the valve body is accommodated in the valve hole. 5. The damping valve according to claim 4, wherein an elastic body is provided between the flange and the bottom of the seat member to urge the valve body in a direction away from the valve seat. An annular seal member that is in sliding contact with the outer periphery of the sliding portion of the shaft is laminated on the valve hole side of the bearing portion of the guide member, and the seal member is prevented from coming off between the bearing portion of the guide member and the seat member. 6. The damping valve according to claim 4 or 5, wherein an annular stopper for prevention is sandwiched. The said valve main body and the said shaft are integrated, The damping valve as described in any one of Claim 1 to 6 characterized by the above-mentioned. A cylinder, a piston that is slidably inserted into the cylinder and divides the cylinder into a compression side chamber and an extension side chamber, a piston rod that is inserted into the cylinder and connected to the piston, and the outside of the cylinder A reservoir provided in the channel, a flow path communicating one of the compression side chamber and the extension side chamber to the reservoir, and disposed in the middle of the flow path and communicating with one of the compression side chamber and the extension side chamber and the reservoir. A case provided with a valve hole, an annular valve seat provided in the middle of the valve hole between the one chamber and the other chamber, and axially movable in the valve hole. In a shock absorber provided with a valve body that can be moved to and away from the valve seat, and an actuator that is provided outside the case and drives the valve body in the axial direction,
The valve body is slidably supported by the case and a valve body having a flange slidably in contact with the inner periphery of the valve hole, a valve head extending from the flange and seating on the valve seat at the tip. A shaft that protrudes out of the valve hole and transmits the thrust of the actuator to the valve body,
The inside of the valve hole is partitioned by the valve body into a front side chamber that leads to the other chamber between the valve seat and the flange, and a back side chamber on the side opposite to the valve seat from the flange,
The range of sliding contact with the case of the shaft as a sliding portion, the cross-sectional area of the sliding portion is smaller than the cross-sectional area of the flange,
The shock absorber according to claim 1, wherein the front side chamber and the back side chamber communicate with each other through a communication passage. The flow path passes through the piston rod, communicates one of the pressure side chamber and the extension side chamber to the reservoir, and has a housing in which the case and the actuator are detachably accommodated at the tip of the piston rod. The shock absorber according to claim 8, wherein the shock absorber is provided.

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