WO2018016132A1 - Damping force-adjusting shock absorber - Google Patents

Abstract

The purpose of the present invention is to provide a novel damping force-adjusting shock absorber capable of limiting as much as possible the occurrence of vibrations in a pilot valve due to changes in the flow of hydraulic oil when shifting to a fail operation state or when returning from a fail operation state. The present invention comprises a valve chamber 51 for housing a valve part, and an actuator for controlling the valve part by the thrust of a solenoid 154. The valve part is provided with: a first valve section 55d for dividing the valve chamber 51 into an upstream chamber 51a and a downstream chamber 51b and for opening and closing a first flow-through port through which the upstream chamber 51a connects to an upstream area further upstream thereof; a second valve section 55c for opening and closing a second flow-through port through which the downstream chamber 51b connects to a downstream area further downstream thereof; a communication passage 55b through which the upstream chamber 51a is in communication with the downstream chamber 51b; a fail passage 80a for circumventing the second valve section 55c and connecting the upstream chamber 51a to the downstream chamber 51b and the downstream area on the downstream side of the downstream chamber 51b; and a fail valve 82.

Description

Damping force adjustable shock absorber

The present invention relates to a shock absorber that generates a damping force with respect to a stroke of a piston rod, and more particularly to a damping force adjusting type shock absorber that can control the damping force.

For shock absorbers used in vehicles such as automobiles, it is desirable that the damping force can be changed freely according to the running conditions. Therefore, a damping force adjusting type shock absorber is known that detects a traveling state and changes the operating pressure of a valve that opens and closes an oil passage provided in a piston of the shock absorber by a linear solenoid.

For example, in Japanese Patent No. 3285302 (Patent Document 1), in a semi-active suspension mounted on an automobile, a main valve that opens and closes a main passage communicating two oil chambers, and an oil chamber on a high-pressure side is connected to the main valve. And a pilot passage that connects the auxiliary oil chamber to the low pressure side oil chamber can be opened and closed, and when the pressure in the auxiliary oil chamber exceeds the set pressure, the pilot passage is opened. Damping force adjustment type safeguard equipped with a pilot valve that changes the closing direction force to the main valve by opening and releasing hydraulic oil from the auxiliary oil chamber to the low pressure side, and a set pressure variable means that variably controls the set pressure Is disclosed.

In the damping force adjustment type safety device described in Patent Document 1, a downward force corresponding to the excitation force of the linear solenoid is applied to the pilot valve via the plunger, and the pilot valve is opened by controlling this excitation force. The internal pressure of the auxiliary oil chamber that starts is changing. Here, when the power supply to the linear solenoid is stopped, the connection to the pilot passage is stopped by the outer peripheral surface of the disk portion fixed to the pilot valve, and the upstream region of the pilot valve below the disk portion A ball valve is disposed in the communication passage communicating with the pilot passage, and this ball valve is biased in the closing direction by a biasing spring.

And when a temporary abnormality occurs in the control device or the like and the linear solenoid is de-energized, the force that pushes the pilot valve downward disappears. For this reason, the pilot valve is pushed up by the restoring force of the leaf spring, and the outer peripheral surface of the disk portion operates so as to close the communication with the pilot passage.

Therefore, when the internal pressure of the auxiliary oil chamber becomes the valve opening set pressure of the ball valve, the ball valve opens and the hydraulic oil is allowed to escape from the upstream region of the pilot valve to the pilot passage. As a result, the auxiliary oil chamber is held at the valve opening set pressure of the ball valve, and a constant damping force can be generated.

Japanese Patent No. 3285302

However, in the structure of the damping force adjustment type shock absorber described in Patent Document 1, the flow of hydraulic oil when shifting to the fail operation state where the control current flowing through the linear solenoid is interrupted or when returning from the fail operation state There has been a problem that the fluid force acting on the pilot valve fluctuates due to the change in direction, and the pilot valve is likely to vibrate.

An object of the present invention is to provide a novel damping force adjustment type that can suppress the occurrence of vibrations in a pilot valve due to a change in the flow of hydraulic oil as much as possible at the time of transition to a fail operation state or at the return from the fail operation state. It is to provide a shock absorber.

The present invention relates to a damping force adjusting type shock absorber having a control valve assembly that generates a damping force by controlling a flow of hydraulic oil generated by sliding of a piston in a cylinder. And a valve chamber that houses the valve body portion, and an actuator that controls the valve body portion by the thrust of the solenoid, and the valve body portion divides the valve chamber into an upstream chamber and a downstream chamber, A first valve portion that opens and closes a first flow port connected to an upstream region upstream from this, a second valve portion that opens and closes a second flow port connected to a downstream chamber and a downstream region downstream from this, an upstream chamber and a downstream chamber And a fail valve disposed in the fail passage, which bypasses the second valve portion and connects the downstream chamber and the downstream region, and a fail valve disposed in the fail passage.

Further, when the actuator is operating, the working fluid is allowed to flow to the reservoir through the path of the first valve portion, the upstream chamber, the communication path, the downstream chamber, the second valve portion, and the downstream region, and the operation of the actuator is stopped. In this state, the working fluid is made to flow to the reservoir through the first valve portion, the upstream chamber, the communication passage, the downstream chamber, the fail passage in which the fail valve is opened, and the passage in the downstream region. It is.

According to the present invention, at the time of transition to the fail operation state, or at the time of return from the fail operation state, the fluctuation of the fluid force due to the change of the flow of hydraulic oil acting on the first valve portion can be reduced, and the first valve portion is vibrated Can be suppressed.

1 is a hydraulic circuit diagram of a semi-active suspension to which the present invention is applied. It is sectional drawing at the time of the normal operation state of the damping force adjustment type shock absorber which becomes the 1st Embodiment of this invention. FIG. 3 is an enlarged cross-sectional view in which the vicinity of a pilot valve portion in a normal operation state of the damping force adjusting shock absorber shown in FIG. 2 is enlarged. It is the figure which looked at the pilot valve shown in FIG. 3 from the upper part of FIG. It is the figure which looked at the pilot valve outer diameter channel | path part shown in FIG. 3 from the upper direction of FIG. FIG. 4 is a view of the pilot valve downstream side seat member shown in FIG. 3 as viewed from above in FIG. 3. It is the figure which looked at the fail valve seat member shown in FIG. 3 from the upper part of FIG. It is the figure which looked at the fail valve shown in FIG. 3 from the upper part of FIG. FIG. 3 is a cross-sectional view of the damping force adjusting shock absorber shown in FIG. 2 in a fail operation state. FIG. 10 is an enlarged cross-sectional view in which the vicinity of the pilot valve portion in the fail operation state of the damping force adjusting shock absorber shown in FIG. 9 is enlarged. It is sectional drawing at the time of the fail operation state of the damping force adjustment type buffer which becomes the 2nd Embodiment of this invention. FIG. 12 is an enlarged cross-sectional view in which the vicinity of a pilot valve portion in a normal operation state of the damping force adjusting shock absorber shown in FIG. 11 is enlarged. It is the figure which looked at the pilot valve outer diameter channel | path part shown in FIG. 12 from the upper direction of FIG. It is the figure which looked at the pilot valve downstream seat member shown in Drawing 12 from the upper part of Drawing 12. It is the expanded sectional view which expanded the pilot valve part vicinity of the fail operation state of the damping force adjustment buffer shown in FIG. It is a block diagram which shows the structure of the other semi-active suspension to which this invention is applied. FIG. 17 is a cross-sectional view of the vicinity of the damping force adjusting shock absorber shown in FIG. 16. It is the expanded sectional view which expanded the pilot valve part vicinity of the normal operation state of the damping force adjustment type shock absorber shown in FIG. It is the expanded sectional view which expanded the pilot valve part vicinity of the fail operation state of the damping force adjustment buffer shown in FIG.

Embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications and application examples are included in the technical concept of the present invention. It is included in the range.

Here, before explaining the present invention, a supplementary explanation will be given on the problems in the damping force adjusting shock absorber described in Patent Document 1.

As shown in FIGS. 3 and 4 of Patent Document 1, hydraulic oil is supplied to the pilot passage from the upstream region of the pilot valve through a through oil passage formed in the disk portion of the pilot valve during normal operation, and the pilot is used during failure. The hydraulic oil is supplied to the pilot passage through the ball valve while bypassing the pilot valve from the upstream region of the valve. Thus, the oil path through which the hydraulic oil flows is switched between the normal operation and the fail operation. When the operation oil is supplied to the pilot passage through the through oil passage formed in the disk portion, the pilot valve is vibrated at the time of transition from the state in which the operation oil is supplied to the pilot passage through the ball valve. It is expected that it may occur.

In other words, during the failure operation, the hydraulic force that passes through the ball valve causes fluid force to act in the direction of closing the pilot valve, making it easy for the pilot valve to move in the closing direction. The formed disk part also moves simultaneously, the through oil passage formed in the disk part and the pilot passage are connected, and the hydraulic oil flows into the pilot passage. For this reason, the fluid force acting in the direction of closing the pilot valve is weakened, and the pilot valve moves in the opening direction.

Then, when the pilot valve moves in the opening direction, the disk part fixed to the pilot valve cuts off the communication with the pilot passage so that the amount of hydraulic oil passing through the ball valve increases and the pilot valve is closed again. A fluid force acts on the pilot valve to move in the closing direction. This repetition increases the possibility of vibrations in the pilot valve.

こ の This vibration may occur not only when transitioning to the fail operating state but also when returning from the fail operating state. When this vibration occurs, it becomes noise and leaks to the outside, and the product quality of automobiles that require quietness deteriorates.

Therefore, the present invention provides a damping force adjusting type shock absorber capable of suppressing as much as possible vibrations in the pilot valve due to a change in the flow of hydraulic oil when shifting to the fail operating state or when returning from the fail operating state. This is a proposal.

Hereinafter, a damping force adjusting type shock absorber according to a first embodiment of the present invention will be described with reference to the drawings.

Fig. 1 shows the overall configuration of a damping force adjusting shock absorber for a semi-active suspension. As shown in FIG. 1, the shock absorber 1 according to the present embodiment includes a cylinder 2, a reservoir 4, and a damping force generating mechanism 25. It is mounted between two members that can move relative to each other.

In the cylinder 2, a piston 5 is slidably interposed. The piston 5 divides the cylinder 2 into a cylinder upper chamber 2A and a cylinder lower chamber 2B.

The piston rod 6 is connected to the piston 5, and the end of the piston rod 6 opposite to the piston 5 passes through the cylinder upper chamber 2A and protrudes outside the cylinder 2 through an oil seal (not shown). A base valve 10 that separates the cylinder lower chamber 2 </ b> B and the reservoir 4 is provided on the lower end side of the cylinder 2.

The piston 5 is provided with passages 11 and 12 for communicating between the cylinder upper chamber 2A and the cylinder lower chamber 2B. The passage 12 is provided with a check valve 13 that allows only fluid flow from the cylinder lower chamber 2B to the cylinder upper chamber 2A, and the pressure of the fluid on the cylinder upper chamber 2A side reaches a predetermined pressure in the passage 11. When this occurs, a relief valve 14 is provided to open the valve and relieve it to the cylinder lower chamber 2B side.

The base valve 10 is provided with passages 15 and 16 for allowing the cylinder lower chamber 2B and the reservoir 4 to communicate with each other. The passage 15 is provided with a check valve 17 that allows only fluid to flow from the reservoir 4 to the cylinder lower chamber 2B. In the passage 16, the pressure of the fluid on the cylinder lower chamber 2B side reaches a predetermined pressure. A relief valve 18 is provided for opening the valve and relieving it to the reservoir 4 side. The damping force generation mechanism 25 has an upstream side 25 u connected to the cylinder upper chamber 2 </ b> A side and a downstream side 25 d connected to the reservoir 4.

Next, a structure for attaching the damping force generating mechanism 25 to the cylinder 2 and a detailed structure of the damping force generating mechanism 25 will be described with reference to FIGS.

FIG. 2 shows the overall configuration of the damping force generating mechanism 25, and FIG. 3 shows an enlarged configuration around the pilot valve portion and the fail valve portion. In FIG. 2, since it is difficult to discriminate the configuration near the pilot valve unit and the fail valve unit, the description will be given with reference to FIG. The state shown in FIGS. 2 and 3 shows a normal operation state.

The cylinder 2 is formed in a cylindrical shape in which the piston 5 is slidable inside, a separator tube 20 is provided on the outside thereof, and an annular passage 21 is formed between the side wall of the cylinder 2 and the separator tube 20. 21 communicates with the cylinder upper chamber 2A side. On the side wall of the separator tube 20, a cylindrical branch pipe 23 as a small-diameter substantially cylindrical separator tube opening having an opening communicating with the annular passage 21 protrudes. In addition, the outer cylinder 3 has a double cylinder structure in which an outer cylinder 3 is provided, and an annular reservoir 4 is formed between the cylinder 2 and the outer cylinder 3.

An annular opening 24 is provided on the side wall of the outer cylinder 3 so as to face the branch pipe 23. The opening 24 has a larger diameter than the branch pipe 23 and is disposed concentrically with the branch pipe 23. A damping force generating mechanism 25 is attached to the side wall of the outer cylinder 3 by welding so as to face the branch pipe 23 and the opening 24. Note that the separator tube opening (branch pipe 23) is not a branch pipe structure that protrudes radially outward from the separator tube 20 and communicates with the reservoir 4, but may be a simple opening.

The damping force generation mechanism 25 includes a substantially cylindrical case 26 attached so as to cover the opening 24 of the outer cylinder 3, a pilot-type main valve portion 27 provided therein, and an opening of the main valve portion 27. The pilot valve unit 28 is a solenoid-driven pressure control valve that controls the valve pressure, and further includes a fail valve unit 29 that is located downstream of the pilot valve unit 28 and that operates during a failure.

Here, the pilot valve unit 28 and the fail valve unit 29, or the pilot valve unit 28, the fail valve unit 29, and the main valve unit 27 function as a “control valve assembly” in the present embodiment. Accordingly, the pilot valve portion 28 and the fail valve portion 29 are combined to form a “control valve assembly”, and the pilot valve portion 28, the fail valve portion 29, and the main valve portion 27 are combined to form a “control valve assembly”. There is a case.

The case 26 is formed in a bottomed cylindrical shape, and an opening 33 that is larger in diameter than the branch pipe 23 of the separator tube 20 and is connected to the opening 24 of the outer cylinder 3 is formed on the bottom 26 a. It is fixed by welding or the like. Inside the case 26, the main valve 39 that opens and closes the flow path between the passage member 30, the main body 36 that forms the seat portion of the main valve portion 27, and the main body 36 in order from the bottom side (the outer cylinder 3 side). A pilot pin 37 that forms a pilot passage, and a pilot body 38 in which a pilot valve portion 28 and the like are provided are housed. A linear solenoid portion 154 that drives the pilot valve portion 28 is screwed to the opening of the case 26 by a nut 52.

The passage member 30 has a shape in which a flange portion 30b is formed on the outer periphery of one end portion of the cylindrical portion 30a. The cylindrical portion 30a is liquid-tightly fitted into the branch pipe 23 of the separator tube 20, and the flange portion 30b is the case 16. Between the bottom portion 26a and the main body 36. The case bottom 26a is provided with a groove (not shown), and the outer peripheral side of the main body 36 and the liquid chamber 57 formed in the case 26 are communicated with each other.

The main body 36 has a substantially cylindrical shape with a concave portion on one end side (passage member 30 side), an annular groove portion that forms a liquid chamber 57 on the other end side, and a main valve on the outer side (convex portion) of the groove portion. A sheet part is formed between the sheet 39 and the sheet. A cylindrical pilot pin 37 is inserted in the center of the annular groove portion of the main body 36, and a center hole 36a that forms a pilot passage is provided. One end side of the main body 36 sandwiches the passage member 30 with the bottom portion 26 a of the case 26.

The liquid chamber 57 is connected to and communicated with the reservoir 4 side and is a “reservoir side region” located on the downstream side of the main valve 39 in terms of fluid. On the other hand, the upstream side of the main valve 39 is connected to and communicated with the cylinder side via the opening 30 and is a “cylinder side region” located on the upstream side of the main valve 39 in terms of fluid.

A plurality of communication holes are provided between the annular groove on one end side and the other end side of the main body 36, and a pilot pin 37 is fitted in the center hole 36a. The pilot pin 37 is formed in a cylindrical shape having a communication passage having a throttle 37a at the center and a large diameter portion having a large diameter on the outer diameter side in the middle portion, and one end side is inserted into the main body 36, and the like. The end side is fitted to the pilot body 38.

The outside of the pilot body 38 is formed in a cylindrical shape that changes with a step portion so that the outer diameter is smaller than the inner diameter of the case 26 and the main valve portion 27 side is larger than the side opposite to the main valve portion 27. Has been. Further, inside the pilot valve, a concave portion whose diameter changes stepwise is formed on the main valve portion 27 side, and similarly, a concave portion whose diameter changes stepwise on the side opposite to the main valve portion 27 is formed. Has been.

The main valve 39 is slidably disposed in the recess 38a on the main valve portion 27 side of the pilot body 38, and a pilot pin 37 is fitted in a central portion 38b in which the diameter of the recess 38a is further reduced. Thereby, a back pressure chamber 58 of the main valve portion 27 is formed between the main valve 39, the recess 38 a of the pilot body 38, and the outer diameter side of the pilot pin 37. The back pressure chamber 58 communicates with the downstream side of the throttle 37 a of the pilot pin 37.

A pilot valve 55 for opening and closing a flow path between the disc spring 59 and the pilot body 38 from the upstream side and a pilot for forming a fail valve portion 29 are formed in the recess 38c on the opposite side of the pilot valve 38 from the main valve 39. A valve outer diameter passage portion 69, a pilot valve downstream side seat member 80, a fail valve seat member 81, a fail valve 82, a fail valve support portion 83, and a fail valve fixing portion 84 are disposed.

FIG. 4 shows the shape of the pilot valve 55 (as viewed from the downstream chamber side described below), which will be described with reference to this as well.

The pilot valve 55 is formed in a disc shape having a center hole 55f near the center, a convex portion near the central portion around the center hole, and a flange portion 55e on the outer peripheral portion. The convex portion side is formed so as to have a “first valve portion” capable of opening and closing a flow path connected to the pilot pin 37 with the pilot body 38. That is, the pilot valve 55 is formed with a first valve portion 55d, and a connection path between an upstream chamber 51a, which will be described later, and an upstream region (from the upstream chamber 51a to the annular passage 21 side) when viewed from the flow of hydraulic oil connected thereto. In order to open and close, the seat part formed in the pilot body 38 connected to the pilot pin 37 is opened and closed.

Further, the pilot valve 55 is integrally provided with an annular convex portion 55c whose diameter increases stepwise on the side opposite to the convex portion (first valve portion 55d). The outer diameter of the annular convex portion 55c formed in the flange portion 55e is set so that the pilot valve 55 can operate through a small gap or slide in a hole inside the pilot valve outer diameter passage portion 69 described later. Has been.

Further, the valve chamber 51 in which the pilot valve 55 is arranged is separated into an upstream upstream chamber 51a and a downstream downstream chamber 51b by the flange portion 55e. A plurality of communication passages 55b are formed in the flange portion 55e of the pilot valve 55 to communicate the upstream chamber 51a and the downstream chamber 51b. That is, the communication path 55b is formed in the pilot valve 55, in other words, the first valve portion 55d itself.

Furthermore, an annular convex portion 55c is integrally formed on the outermost peripheral portion of the flange portion 55e opposite to the first valve portion 55d. The annular convex portion 55c functions as a “second valve portion” to be described later, and is hereinafter referred to as an annular convex portion 55c or a second valve portion 55c. In the annular region between the first valve portion 55d and the second valve portion 55c, a plurality of the above-described communication passages 55b are provided for each predetermined angle.

FIG. 5 shows the shape of the pilot valve outer diameter passage portion 69 (as viewed from the downstream chamber side described below), which will be described with reference to this as well.

As shown in FIG. 5, the pilot valve outer diameter passage portion 69 has an inner diameter portion set to a diameter capable of sliding the second valve portion 55 c of the pilot valve 55, and the outer diameter portion is different from the main valve portion 27 of the pilot body 38. It has a disk shape so as to be housed in the recess on the opposite side, and a valve chamber 51 is formed between the inside of the recess of the pilot body 38 and the inside diameter of the pilot valve outer diameter passage portion 69. Further, a communication passage 69a through which the hydraulic oil flows from the inner diameter side toward the outer diameter side is provided in the downstream region when viewed from the flow of the hydraulic oil from the downstream chamber 51b, and a space formed by the pilot body 38 on the outer diameter side. 69b.

FIG. 6 shows the shape of the pilot valve downstream seat member 80 (as viewed from the downstream chamber side described below), which will be described with reference to this as well.

As shown in FIG. 6, the pilot valve downstream seat member 80 is formed in a disk shape having a hole in the center, and has a plurality of communication holes 80a that communicate the upstream side and the downstream side as viewed in the flow of hydraulic oil. Is provided. A second valve portion 55c that opens and closes the communication passage 69a is brought into contact with the tip of the annular convex portion 55c of the pilot valve at a position outside the position of the communication hole 80a. A space 80b is provided between the pilot body 38 and the outer diameter side.

FIG. 7 shows the shape of the fail valve seat member 81 (as viewed from the downstream chamber side described below), which will be described with reference to this as well.

The fail valve seat member 81 is formed in a disc shape having a hole in the center as shown in FIG. 7, and has a shape in which a seat hole 81a larger than the communication hole of the pilot valve downstream side seat member 80 is provided, On the outer diameter side, it has a disc shape in which a space 81b is provided between the pilot body 38 and the outer diameter side.

FIG. 8 shows the shape of the fail valve 82 (as viewed from the downstream chamber side described below), which will be described with reference to this as well.

The fail valve 82 has a disk shape as shown in FIG. 8, and is provided with an opening / closing portion 82a capable of opening and closing a seat hole 81a provided in the fail valve seat member 81. A space 82b is provided between the two. The opening / closing part 82a is formed so as to be elastically deformable, can be operated with the outside as a fulcrum in a direction perpendicular to the paper surface of FIG. 8, has a role of a disk-shaped spring, and operates as a relief valve that operates at a predetermined pressure or higher. Function.

The fail valve support portion 83 is provided on the downstream side of the fail valve 82 and has a disk shape with a hole in the center, and is held so that the outside of the fail valve 82 serves as a fulcrum for the operation of the opening / closing portion 82a. The inner diameter of the center hole is determined to be outside the outermost peripheral part of the opening / closing part 82a of the fail valve 82, and a space 83b is provided between the pilot hole 38 and the outer diameter side.

The fail valve fixing portion 84 is installed on the downstream side of the fail valve support portion 83, has a disk shape, and is provided with a communication path that communicates from the upstream to the downstream at the center portion and the outer edge portion. The fail valve fixing portion 84 is fixed to the pilot body 38, and a space 84b is provided between the pilot valve 38 and the outer diameter side. The communication path at the center and outer edge of the fail valve fixing portion 84 communicates with the liquid chamber 57 outside the pilot body 38 and further communicates with the reservoir 4.

The linear solenoid 154 has a bottomed cylindrical shape, and a case member 158 that forms a bore and a lower end portion of the plunger 53 (the left side in FIG. 2) can slide in a solenoid case 71 having a hole therein. And a core 72 formed with a recess 72b to be fitted to. Further, the case member 158 is formed in a substantially cylindrical shape, and the upper end portion 73 (the right side in FIG. 2) is fitted in a recess formed in the lower end surface of the coil cap 127. On the other hand, the core 72 is formed in a substantially cylindrical shape, a flange portion is formed on the outer periphery of the lower end portion (left side in FIG. 2), and is fitted to a step portion provided outside the bottom portion of the solenoid case 71.

The pilot valve 55 is fixed to an operation pin 79 fixed to a plunger 53 of a linear solenoid 154 installed on the opposite side to the pilot body 38. The coil 40 is wound around the plunger 53, and the plunger 53, the core 72, and the case member 158 are disposed near the center in the solenoid case 71. When a current flows through the coil 40, an attractive force is generated between the plunger 70 and the core 72 in the left direction in FIG.

On the other hand, the outer circumference of the disk spring 59 is fixed between the root portion of the convex portion of the pilot valve 55 and the step portion of the pilot body 38. The disc spring 59 is a plate-like spring and is arranged so as to generate an urging force in a direction to open the flow path between the pilot body 38 and the pilot valve 55.

Although not shown, a flow path is formed in a part of the disk spring 59, and the lower and upper chambers in FIG. A communication passage forming a communication passage 70 is provided at the center of the operation pin 79 and the pilot valve 55 and communicates with a liquid chamber 76 provided on the opposite side of the operation pin 79 from the pilot valve 55. The operating pin 79 is supported by a pair of bushes 62 and 63 assembled inside the core 72 so as to be movable in the vertical direction (left and right direction in FIG. 2).

The specific operation of the damping force adjustment type shock absorber according to the present embodiment having the above-described configuration will be described. First, the operation in the normal state will be described with reference to FIGS.

As shown in FIG. 1, during the extension stroke of the piston rod 6, the check valve 13 of the piston 5 is closed by the movement of the piston 5 in the cylinder 2 (upward in FIG. 1), and before the relief valve 14 is opened. Since the hydraulic oil on the cylinder upper chamber 2A side is pressurized, the hydraulic oil flows from the branch pipe 23 of the separator tube 20 to the passage member 30 of the damping force generation mechanism 25 through the annular passage 21.

Then, the hydraulic oil flowing in from the passage member 30 passes through the main valve portion 27 and the pilot valve portion 28 and is surrounded by the case 26 along the flow line F1 indicated by the solid line and the flow line F2 indicated by the broken line. It flows into the chamber 57 and further flows into the reservoir 4 through the space (passage groove) at the end of the case 26 and the opening 24 of the outer cylinder 3.

In addition, the flow line F2 of the hydraulic oil flowing through the pilot valve 28 is shown in detail in FIG. As shown in FIG. 3, the hydraulic oil flowing in from the “first flow port” formed between the pilot body 38 and the first valve portion 55 d of the pilot valve 55 flows into the upstream chamber 51 a and forms in the disc spring 59. The plurality of communication passages 55b of the pilot valve 55 are reached through the flow path (not shown). Here, the cross-sectional area through which hydraulic fluid passes through the inflow port on the upstream side (pilot pin 37 side) from the "first flow port" formed between the pilot body 38 and the first valve portion 55d of the pilot valve 55 is: It is set larger than the total cross-sectional area of the communication passage 55b.

Then, the hydraulic oil that has flowed out of the communication passage 55b reaches the downstream chamber 51b. Here, the second valve portion 55 c formed on the outer peripheral portion of the flange portion 55 e of the pilot valve 55 operates so as to open the communication passage 69 a of the pilot valve outer diameter passage portion 69. For this reason, the hydraulic oil that has flowed into the downstream chamber 51b from the upstream chamber 51a through the first valve portion 55d passes through the communication passage 69a, passes through the spaces 80b and 82b further downstream of the downstream chamber 51b, and enters the liquid chamber 57. It flows to reach the opening 24 of the outer cylinder 3 and finally flows into the reservoir 4.

At this time, as shown in FIG. 1, the fluid corresponding to the movement of the piston 5 in the expansion stroke opens the check valve 17 of the base valve 10 from the reservoir 4 and flows into the cylinder lower chamber 2B. When the pressure in the cylinder upper chamber 2A reaches the valve opening pressure of the relief valve 14 of the piston 5, the relief valve 14 is opened, and the pressure in the cylinder upper chamber 2A is relieved to the cylinder lower chamber 2B. An excessive pressure increase of 2A can be prevented.

On the other hand, during the contraction stroke of the piston rod 6, the check valve 13 of the piston 5 opens and the check valve 17 of the passage 15 of the base valve 10 closes due to the movement of the piston 5 in the cylinder 2 (downward in FIG. 1). Before the relief valve 18 is opened, the hydraulic oil in the piston lower chamber 2B flows into the cylinder upper chamber 2A, and the fluid that the piston rod 6 has entered into the cylinder 2 extends from the cylinder upper chamber 2A as described above. It flows to the reservoir 4 through the same path as the stroke.

When the pressure in the cylinder lower chamber 2B reaches the valve opening pressure of the relief valve 18 of the base valve 10, the relief valve 18 is opened, and the pressure in the cylinder lower chamber 2B is relieved to the reservoir 4, whereby the cylinder lower chamber An excessive pressure increase of 2B can be prevented.

Thus, in the expansion / contraction stroke of the piston rod 6, before the main valve portion 27 of the damping force generating mechanism 25 is opened (when the piston speed is in the low speed range), a damping force is generated by the pilot valve portion 28, and the main After the valve portion 27 is opened (when the piston speed is in the high speed range), a damping force is generated according to the opening degree. Then, the damping force can be adjusted by adjusting the control pressure of the pilot valve portion 28 by the energization current to the coil 40. As a result, the internal pressure of the back pressure chamber 58 changes and the main valve portion 27 opens. The valve pressure and opening can be adjusted.

Next, the operation in a state where the energization of the linear solenoid 154 is stopped will be described with reference to FIGS. In FIG. 9, it is difficult to discriminate the configuration in the vicinity of the pilot valve portion and the fail valve portion, so that description will be given with reference to FIG. 10 in which this portion is enlarged.

For example, when the power supply to the coil 40 is interrupted due to a vehicle stoppage due to a signal waiting or the like, or a failure of the control device, in the present embodiment, the first valve portion 55d is “always open” and is closed during normal operation. By restricting the flow of hydraulic oil in place of the pilot valve portion 28 that is “always open” by opening the fail valve portion 29 that is valved, an excessive decrease in the damping force is suppressed and an appropriate amount is achieved. The damping force can be maintained.

In this way, a state in which the power supply to the coil is interrupted is called a fail operation state. Next, an operation when the normal operation state is shifted to the fail operation state will be described below.

In the normal operation state, as shown in FIGS. 2 and 3, the hydraulic fluid flows along the streamline F2 indicated by the broken line on the pilot valve portion 28 side, and along the streamline F1 indicated by the solid line on the main valve portion 27 side. Flowing.

As shown in FIG. 3, the flow line F2 flowing on the pilot valve portion 28 side is “the first valve portion 55d formed between the pilot body 38 and the pilot valve 55” → “the upstream chamber 51a” → “the pilot valve 55 The provided communication passage 55b "⇒" the downstream chamber 51b "⇒" the second valve portion 55c formed in cooperation with the pilot valve downstream seat member 80 "⇒" the communication passage 69a of the pilot valve outer diameter passage portion 69 "⇒ It finally flows to the reservoir 4 through a path of “spaces 69b, 80b, 82b, 83b, 84b” → “liquid chamber 57”. The main valve portion 27 side passes through the seat portion of the main valve 39, merges with the flow on the pilot portion 28 side in the liquid chamber 57, and flows to the reservoir 4.

On the other hand, in the case of a fail operation state in which the power is cut off, the operation is performed as shown in FIGS. As shown in FIGS. 9 and 10, since the linear solenoid 154 does not operate, the first valve portion 55 d that is in contact with the pilot body 38 constituting the pilot valve portion 28 is opened by the disc spring 59. In this state, the second valve portion 55c formed in the pilot valve 55 also moves simultaneously, and the “second flow port” formed between the second valve portion 55c and the pilot valve downstream side seat member 80 is closed. As a result, the flow passage 69a of the pilot valve outer diameter passage portion 69 is blocked.

At this time, since the first valve portion 55d is opened, the hydraulic oil from the pilot pin 37 located in the upstream region on the upstream side of the first valve portion 55d flows into the valve chamber 51, and the entire valve chamber 51 is Pressure increases. When the pressure in the valve chamber 51 becomes a predetermined pressure, the fail valve 82 is deformed so as to open a flow path between the fail valve seat member 81 and the pressure.

The fail valve 82 is provided with an opening / closing portion 82a capable of opening and closing a seat hole 81a provided in the fail valve seat member 81. The opening / closing portion 82a is formed to be elastically deformable and functions as a relief valve that opens at a predetermined pressure or higher. is doing. Accordingly, the hydraulic oil at this time does not pass through the second valve portion 55c but flows around the second valve portion 55c to the fail valve 82 side.

As shown in FIG. 10, the flow line F2 flowing on the pilot valve portion 28 side is “the first valve portion 55d formed between the pilot body 38 and the pilot valve 55” → “the upstream chamber 51a” → “the pilot valve 55 “Communication passage 55b provided” ⇒ “Downstream chamber 51b” ⇒ “Communication passage 80a formed in the pilot valve downstream seat member 80” ⇒ “Seat hole 81a provided in the fail valve seat member 81” ⇒ “Opening / closing portion of the fail valve 82 The flow path is opened by 82a ”⇒“ liquid chamber 57 ”and finally flows to the reservoir 4. The main valve portion 27 side passes through the seat portion of the main valve 39, merges with the flow on the pilot portion 28 side in the liquid chamber 57, and flows to the reservoir 4.

As can be understood from FIGS. 3 and 10, when shifting from the normal operation state to the fail operation state, or when shifting from the fail operation state to the normal operation state, the upstream chamber 51 a of the valve chamber 51 of the pilot valve 55 The flow of hydraulic oil in the downstream chamber 51b always continues to flow from the upstream chamber 51a toward the downstream chamber 51b.

Thus, since the flow of the hydraulic oil from the upstream chamber 51a to the downstream chamber 51b is continued even when the normal operation state is changed to the fail operation state, it is generated by the hydraulic oil flowing through the upstream chamber 51a and the downstream chamber 51b. The fluid force hardly fluctuates. Therefore, the degree to which the fluid force acting on the pilot valve 55 fluctuates due to the change in the operation state becomes small, and the transition to the fail operation state can be performed without performing the behavior of the pilot valve 55 vibrating.

Similarly, when returning from the fail operation state to the normal operation state, the flow of the hydraulic oil from the upstream chamber 51a to the downstream chamber 51b is continued, so that the flow generated by the hydraulic oil flowing through the upstream chamber 51a and the downstream chamber 51b. The physical strength will hardly change. Therefore, the degree to which the fluid force acting on the pilot valve 55 fluctuates due to the change of the operation state is reduced, and the normal operation state can be shifted without performing the behavior of the pilot valve 55 vibrating.

Note that when the flow rate of the hydraulic oil is high, the communication passage 55b formed in the flange portion 55e of the pilot valve 55 may become a resistance. In this case, the pressure in the downstream chamber 51b decreases at the moment when the fail valve portion 29 is opened as the relief pressure. In this case, the force in the valve opening direction of the first valve portion 55d of the pilot valve 55 is slightly increased. Thus, no vibrational phenomenon occurs.

As described above, according to the present embodiment, the valve chamber 51 is divided into the upstream chamber 51a and the downstream chamber 51b by the pilot valve 55, and the first valve portion 55d that opens and closes the inlet to the upstream chamber 51a, and the downstream chamber 51b. The second valve portion 55c for opening and closing the outlet communicating with the downstream side is provided to the upstream chamber 51a and the downstream chamber 51b through the communication passage 55b formed in the flange portion 55e of the pilot valve 55, and the downstream chamber 51b. By providing the fail valve portion 27 that opens and closes the passage communicating with the downstream side, it is possible to suppress the vibration of the pilot valve that occurs at the time of transition between the normal operation state and the fail operation state.

In the present embodiment, the example in which the fail valve 82 is configured by a disk-shaped spring is shown. However, if the flow of the hydraulic oil does not change, a ball valve type formed by a ball valve and a spring that biases the valve in the closing direction is shown. It may be a valve.

Next, a second embodiment of the present invention will be described with reference to FIGS. 11 to 15. In this embodiment, the communication passage 55 b connecting the upstream chamber 51 a and the downstream chamber 51 b is provided as a flange of the pilot valve 55. This is different from the first embodiment except that it is not formed in the portion 55e but separately formed near the outside of the pilot valve 55. Therefore, the description which overlaps with Example 1 is abbreviate | omitted in the following description.

FIG. 11 shows the overall configuration of the damping force generation mechanism 25, and FIG. 12 shows an enlarged configuration around the pilot valve portion and the fail valve portion. In FIG. 11, it is difficult to discriminate the configuration in the vicinity of the pilot valve portion and the fail valve portion, so that description will be given with reference to FIG. The state shown in FIG. 12 shows a normal operation state, and the state shown in FIG. 15 shows a fail operation state.

As shown in FIGS. 11 and 12, the flange portion 55e of the pilot valve 55 of the present embodiment is not provided with a communication passage 55b for communicating the upstream chamber 51a and the downstream chamber 51b as shown in the first embodiment. .

Instead of the communication passage 55b, the upstream chamber 51a and the downstream chamber are provided in the pilot valve outer diameter passage portion 69 and the pilot valve downstream side seat member 80 so as to be located outside the pilot valve 55 and outside the pilot valve 55. A communication path 69c that communicates with 51b is newly provided. For this reason, the shapes of the pilot valve outer diameter passage portion 69 and the pilot valve downstream side seat member 80 are different from those of the first embodiment.

FIG. 13 shows the shape of the pilot valve outer diameter passage portion 69 (as viewed from the downstream chamber side), which will be described with reference to this as well.

As shown in FIG. 13, the pilot valve outer diameter passage portion 69 has an inner diameter portion set to a diameter capable of sliding on the second valve portion 55 c of the pilot valve 55, and the outer diameter portion is different from the main valve portion 27 of the pilot body 38. It has a disk shape so as to be housed in the recess on the opposite side, and a valve chamber 51 is formed between the inside of the recess of the pilot body 38 and the inside diameter of the pilot valve outer diameter passage portion 69. Further, a communication passage 69a through which hydraulic oil flows from the inner diameter side toward the outer diameter side is provided on the downstream side, and communicated with a space 69b formed by the pilot body 38 on the outer diameter side.

Further, a plurality (four) of communication passages 69c that penetrate both surfaces of the disc-shaped pilot valve outer diameter passage portion 69 and communicate with the upstream side and the downstream side of the pilot valve outer diameter passage portion 69 are provided. This communication path 69c becomes a part instead of the communication path 55b.
Here, the second valve portion 55 c of the pilot valve 55 is a “second flow port” on the inner diameter side of the communication passage 69 a through which hydraulic oil flows from the inner diameter side to the outer diameter side formed in the pilot valve outer diameter passage portion 69. Is configured to open and close the opening. In this case, in the normal operation state, the second valve portion 55c of the pilot valve 55 opens the "second flow port" of the communication passage 69a, and in the fail operation state, the second valve portion 55c is moved by the movement of the pilot valve 55. It operates to close the “second circulation port” 69a.

FIG. 14 shows the shape of the pilot valve downstream seat member 80 (as viewed from the downstream chamber side), which will be described with reference to this as well.

As shown in FIG. 14, the pilot valve downstream seat member 80 is formed in a disc shape having a hole in the center, and penetrates both surfaces of the disc-shaped pilot valve downstream seat member 80 so as to be fluidly viewed. A plurality of communication holes 80a are provided for communicating the upstream side and the downstream side. The pilot valve downstream seat member 80 is provided with a communication passage 80 c at a position corresponding to the communication passage 69 c of the pilot valve outer diameter passage portion 69. This communication path 80c is also a part of the communication path 55b. Therefore, the communication path 69c and the communication path 80c replace the communication path 55b.

Further, a groove 80d that guides the flow from the communication passage 80c to the inner diameter side is provided on the downstream side of the pilot valve downstream seat member 80, and the flow is guided to a position corresponding to the seat hole 81a portion of the fail valve seat member 81. It has become. Further, a groove 80e that communicates the communication path 80a and the groove 80d is provided. The other configuration is the same as that of the first embodiment.

11 and 12, the operation will be described next. Since the operation other than the pilot valve section 28 is the same as that of the first embodiment, the operation of the pilot valve section 28 will be described.

In the normal operation state, the streamline F2 flowing through the pilot valve section 28 is as shown in FIG. The second valve portion 55c of the pilot valve 55 is configured to open and close an opening on the inner diameter side of the communication passage 69a through which hydraulic oil flows from the inner diameter side to the outer diameter side formed in the pilot valve outer diameter passage portion 69. Therefore, in the normal operation state, the second valve portion 55c of the pilot valve 55 opens the communication passage 69a.

Accordingly, the hydraulic oil is “the first valve portion 55d formed between the pilot body 38 and the pilot valve 55” → “upstream chamber 51a” → “the communication passage 69c provided in the pilot valve outer diameter passage portion 69” → “pilot "Communication passage 80c, groove 80d, groove 80e of valve downstream seat member 80" ⇒ "communication passage 80a of pilot valve downstream seat member 80" ⇒ "downstream chamber 51b" ⇒ "communication passage 69a of pilot valve outer diameter passage 69" ”⇒“ spaces 69 b, 80 b, 82 b, 83 b, 84 b ”⇒“ liquid chamber 57 ”finally flows to the reservoir 4.

On the other hand, the operation is as shown in FIG. As shown in FIG. 15, since the linear solenoid 154 does not operate, the first valve portion 55 d that is in contact with the pilot body 38 constituting the pilot valve portion 28 is opened by the disc spring 59. In this state, the second valve portion 55c formed in the pilot valve 55 also moves, so that the second valve portion 55c closes the communication passage 69a of the pilot valve outer diameter passage portion 69.

At this time, since the first valve portion 55d is opened, the hydraulic oil from the pilot pin 37 located on the upstream side of the first valve portion 55d flows into the valve chamber 51, and the pressure of the entire valve chamber 51 increases. . When the pressure in the valve chamber 51 becomes a predetermined pressure, the fail valve 82 is deformed so as to open a flow path between the fail valve seat member 81 and the pressure.

The fail valve 82 is provided with an opening / closing part 82a capable of opening and closing a seat hole 81a provided in the fail valve seat member 81 as in the first embodiment. The opening / closing part 82a is formed to be elastically deformable and is opened at a predetermined pressure or more. It functions as an operating relief valve. Accordingly, the hydraulic oil at this time does not pass through the second valve portion 55c but flows around the second valve portion 55c to the fail valve 82 side.

The hydraulic oil is “the first valve portion 55d formed between the pilot body 38 and the pilot valve 55” → “the upstream chamber 51a” → “the communication passage 69c provided in the pilot valve outer diameter passage portion 69” → “the pilot valve” "Communication passage 80c, groove 80d, groove 80e of downstream seat member 80" ⇒ "seat hole 81a provided in fail valve seat member 81" ⇒ "channel opened by opening / closing part 82a of fail valve 82" ⇒ "liquid chamber 57 ”finally flows to the reservoir 4.

With the configuration as described above, the same operation and effect as in the first embodiment can be obtained, and by providing the communication path between the upstream chamber and the downstream chamber on the outer peripheral side of the pilot valve, it is not necessary to provide the communication path in the pilot valve. Thus, it is possible to reduce the overall size of the damping force adjusting shock absorber.

Next, a third embodiment of the present invention will be described with reference to FIG. 16 to FIG. 19. In this embodiment, the first embodiment is the point that the damping force generating mechanism 25 is arranged in the cylinder 2. The other configurations are the same as those in the first embodiment. Therefore, the description which overlaps with Example 1 is abbreviate | omitted in the following description.

FIG. 17 shows a configuration of the damping force generation mechanism 25, and FIGS. 18 and 19 show an enlarged configuration around the pilot valve portion and the fail valve portion. In FIG. 17, it is difficult to discriminate the configuration in the vicinity of the pilot valve portion and the fail valve portion, so that description will be made with reference to FIGS. The state shown in FIG. 18 shows a normal operation state, and the state shown in FIG. 19 shows a fail operation state.

As shown in FIG. 16, the damping force adjustment type shock absorber 1 according to the present embodiment has a multi-cylinder structure in which an outer cylinder 3 is provided on the outer side of a cylinder 2, and between the cylinder 2 and the outer cylinder 3. The reservoir 4 is formed. A piston valve 5 is slidably fitted in the cylinder 2, and the piston valve 5 divides the inside of the cylinder 2 into two chambers, a cylinder upper chamber 2A and a cylinder lower chamber 2B.

At the lower end of the cylinder 2, a base valve 10 that partitions the cylinder lower chamber 2B and the reservoir 4 is provided. The base valve 10 is provided with passages 15 and 16 that communicate between the cylinder lower chamber 2 </ b> B and the reservoir 4. The passage 15 is provided with a check valve 17 that allows only hydraulic fluid to flow from the reservoir 4 side to the cylinder lower chamber 2B side. On the other hand, the passage 16 is provided with a disk-like relief valve 18 that opens when the pressure of the hydraulic oil on the cylinder lower chamber 2B side reaches a predetermined pressure and relieves this pressure to the reservoir 4 side. As working fluid, working oil is sealed in the cylinder 2, and working oil and gas are sealed in the reservoir 4. In FIG. 16, reference numeral 3A is a bottom cap joined to the lower end of the outer cylinder 3, and reference numeral 19 is an attachment eye joined to the bottom cap 3A.

As shown in FIG. 17, the piston valve 5 is provided at the lower end of a substantially cylindrical piston case 121. At the lower end of the piston case 121, a valve seat member 22 from which a main valve 39 described later is detached and seated is provided. The valve seat member 22 includes a cylindrical shaft portion 23, a flange portion 24 formed at the lower end of the shaft portion 23, and a screw portion 125 formed on the outer peripheral surface of the shaft portion 23.

Further, the valve seat member 22 is fixed to the piston case 121 by screwing the screw portion 125 into the screw portion 126 formed in the first shaft hole 142 of the piston case 121. Thereby, the inner flange portion 5 </ b> A of the piston valve 5 is sandwiched between the lower end portion end surface of the piston case 121 and the flange portion 24 of the valve seat member 22, and the piston valve 5 is fixed to the lower end portion of the piston case 121.

The upper end of the piston case 121 is closed by a substantially cylindrical coil cap 127. The coil cap 127 has a threaded portion 128 formed on the outer peripheral surface of the upper end portion, and the threaded portion 128 is screwed into a threaded portion 129 formed at the upper end of the second shaft hole 43 of the piston case 121, thereby 121 is fixed. Further, the coil cap 127 has an annular seal groove formed along the outer peripheral surface of the lower end portion, and the space between the piston cap 121 and the second shaft hole 43 is sealed by an O-ring 130 attached to the seal groove. .

One end of the piston rod 6 is connected to the center of the upper end portion of the coil cap 127, and the other end side of the piston rod 6 passes through the cylinder upper chamber 2A and is further attached to the upper end portions of the cylinder 2 and the outer cylinder 3. The inserted rod guide 8 and oil seal 9 (see FIG. 16) are inserted and extend outside the cylinder 2.

Then, in the piston case 121, and in the cylinder 2, the flow of hydraulic oil between the two chambers of the cylinder upper chamber 2 </ b> A and the cylinder lower chamber 2 </ b> B caused by the movement (extension / contraction) of the piston rod 6 is controlled. A damping force generation mechanism 25 that generates a damping force is provided. The damping force generation mechanism 25 is a hydraulic oil in the pilot chamber 33 during the extension stroke of the main valve portion 27 urged in the valve closing direction (downward in FIG. 17) by the pressure of the pilot chamber 33 described later and the piston rod 6. And a pilot valve portion 28 for discharging the gas to the cylinder lower chamber 2B (downstream chamber). Here, the downstream chamber means a chamber on the other side that is discharged from one chamber and into which hydraulic oil flows when the damping force generation mechanism 25 opens in opposition to the pressure in the pilot chamber 33. .

The main valve part 27 has a main valve 39 accommodated in the lower part of the piston case 121. The main valve 39 is formed in a substantially bottomed cylindrical shape, and a flange portion 137 (outer flange) is formed at the lower end of the main valve 39. The lower end surface 138 of the main valve 39 is provided with an annular seat portion 139 which is provided coaxially with the piston rod 6 and is separated from and seated on the valve seat 40 of the valve seat member 22.

A step is provided between the lower end surface 138 of the main valve 39 between the annular surface 138A (surface 138A on the flange portion 137 side) outside the seat portion 139 and the surface 138B inside the seat portion 139. In addition, by providing the surface 138B inside the seat portion 139 at a position higher than the annular surface 138A, the area of the inner peripheral surface 139A (pressure receiving surface) of the seat portion 139 is secured.

When the seat portion 139 of the main valve 39 is seated on the valve seat 40 of the valve seat member 22, an annular chamber 180 is formed between the lower end portion of the piston case 121, the valve seat member 22, and the main valve 39. ing. A plurality of passages 181 communicating the annular chamber 180 and the cylinder upper chamber 2 </ b> A are provided at the lower end portion of the piston case 121.

In the main valve 39, the outer peripheral surface 41 is slidably inserted into the third shaft hole 44 of the piston case 121, and the outer peripheral surface 137A of the flange portion 137 is slidable into the first shaft hole 42 of the piston case 121. Has been inserted. Thereby, an annular back pressure chamber 46 is formed between the main valve 39 and the first shaft hole 42. A valve seat 49 is provided at the bottom of the main valve 39, from which an annular seat portion 48 formed on a first valve portion 55d of a pilot valve 55 described later is detached and seated.

The valve seat 49 of the main valve 39 is provided with a pilot chamber 33 whose opening is surrounded by the seat portion 48 of the first valve portion 55d of the seated pilot valve 55. The pilot chamber 33 is connected to the back pressure via the communication passage 150. It communicates with the chamber 46. Reference numeral 47 is a pilot valve assembly.

Reference numeral 151 is a compression coil spring that applies a set load to the main valve 39. The main valve 39 is biased downward with respect to the piston case 121 by the spring force of the compression coil spring 151, that is, the valve is closed. It is biased in the direction.

The pilot valve portion 28 includes a pilot valve 55, an operation pin 79 (shaft portion) to which the pilot valve 55 is fixed at a lower end (one end), a plunger 53 (movable element) attached to the outer periphery of the operation pin 79, and a plunger 153. Includes a linear solenoid 154 that drives the motor in the vertical direction (axial direction).

The pilot valve 55 is an on-off valve in which the valve opening pressure is adjusted in response to the energization of the linear solenoid 154. A flange portion 55e is provided on the outer periphery of the pilot valve 55, and the base portion of the flange portion 55e functions as a spring support. The pilot valve 55 has the same configuration as that of the first embodiment, and includes a plurality of communication passages 55b that penetrate the flange portion 55e. The pilot valve 55 is formed with a shaft hole that forms the communication path 70 together with the shaft hole of the operating pin 79.

As shown in FIG. 18, a plurality of stepped portions are provided inside the bottomed cylindrical shape of the main valve 39 in which the pilot valve 55 is disposed, and the bottom, the first bottom, the second bottom, and the third bottom. . A pilot chamber 33 is formed in the first bottom portion, a valve chamber 51 is formed in the next second bottom portion, and is divided into an upstream chamber 51a and a downstream chamber 51b by a flange portion 55e of the pilot valve 55. A plurality of communication passages 55b are formed in the flange portion 55e.

A pilot valve 55 is provided with a third bottom on the upper portion thereof, and a pilot valve downstream seat member 80, a fail valve seat member 81, a fail valve 82, a fail valve support portion 83, a fail valve constituting the fail valve portion 29. A fixing portion 84 is arranged. These structures are the same as those in the first embodiment.

Further, a communication path 39B is formed by the third bottom portion of the main valve 39 and the pilot valve downstream side seat member 80, and this communication path 39B is connected to a communication path 39A communicating with the cylinder lower chamber 2B side. The communication passage 39B is opened and closed by the movement of the second valve portion 55c formed on the outer periphery of the pilot valve flange portion 51e. That is, in the normal operation state, the downstream chamber 51b and the communication path 39B are connected, and in the fail operation state, the connection between the downstream chamber 51b and the communication path 39B is cut off.

The linear solenoid 154 has a case member 158 in which a plunger bore is formed, and a core 72 in which a recess 72b in which a lower end portion of the plunger 153 is slidably fitted is formed. The case member 158 is formed in a substantially cylindrical shape, and a flange portion 158A is formed on the outer periphery of the upper end portion. Further, the upper end portion of the case member 158 is fitted into the concave portion 64 formed on the lower end surface of the coil cap 127. Furthermore, the sleeve 65 is attached to the outer peripheral surface of the case member 158, and the lower end portion of the sleeve 65 is fitted into the fourth shaft hole 45 of the piston case 121. As a result, the case member 158 is positioned coaxially with respect to the center line of the piston case 121.

On the other hand, the core 72 is formed in a substantially cylindrical shape, and a flange portion 72A is formed on the outer periphery of the lower end portion. The core 72 has a flange portion 60 </ b> A fitted into the fourth shaft hole 45 of the piston case 121, and the flange portion 60 </ b> A is formed between the third shaft hole 44 and the fourth shaft hole 45 of the piston case 121. By being abutted against the annular convex portion 66, it is positioned in the vertical direction with respect to the piston case 121.

The inner peripheral surface of the lower end portion of the sleeve 65 is fitted to the outer peripheral surface of the core 72. The sleeve 65 is positioned in the vertical direction with respect to the piston case 121 by abutting the lower end portion against the flange portion 72 </ b> A of the core 72. Further, reference numeral 67 in FIG. 17 is an O-ring that seals between the case member 158 and the sleeve 65, and reference numeral 68 seals between the sleeve 65 and the fourth shaft hole 45 of the piston case 121. O-ring.

On the other hand, the operating pin 79 is supported by a pair of bushes 62 and 63 assembled to the case member 158 and the core 72 so as to be movable in the vertical direction. The operating pin 79 has a shaft hole that constitutes the communication passage 70 described above together with the shaft hole of the pilot valve 55. The communication passage 70 has a lower end side (one end side) communicating with the pilot chamber 33, and an upper end side (the other end side) connected to the cylinder upper chamber 2 </ b> A via the passage 173 (on the upstream side during the extension stroke of the piston rod 6). Room).

The passage 173 includes a shaft hole 174 of the case member 158, a blind hole 175 having a certain depth formed in the center of the lower end surface of the coil cap 127, and an orifice 176 that communicates the blind hole 175 and the cylinder upper chamber 2A. Is included. In other words, one end side of the communication path 70 communicates with the pilot chamber 33, and the other end side communicates directly with the upstream chamber of the two chambers in the cylinder 2, and the cylinder upper chamber 2 </ b> A through the orifice 176 in the extension stroke. Is.

The orifice 176 is provided in the annular passage 177 formed between the upper end portion of the piston case 121 and the coil cap 127 and the upper end portion of the piston case 121, and communicates between the cylinder upper chamber 2A and the annular passage 177. An orifice 178 and a second orifice 179 provided in the coil cap 127 and communicating the blind hole 175 and the annular passage 177 are configured. The shaft hole 174 of the case member 158 and the blind hole 175 of the coil cap 127 form a valve body back pressure chamber of the pilot valve 55.

Further, a retaining ring 171 is attached to the annular groove formed on the outer peripheral surface of the operating pin 79. The retaining ring 171 is engaged with an upper end portion of a pilot spring 172 having a lower end portion sandwiched between the main valve 39 and the compression coil spring 151. As a result, the operating pin 79 is urged upward by the spring force of the pilot spring 172, and when the control current to the linear solenoid 154 is interrupted or when the current is low, the spring force of the pilot spring 172 is reduced to the solenoid. The thrust exceeds the thrust, and the pilot valve portion 28 opens when the seat portion 48 of the first valve portion 55d is disengaged from the valve seat 49 of the main valve 39.

The specific operation of the damping force adjusting type shock absorber according to this embodiment having the above-described configuration will be described. First, the operation in the normal state will be described with reference to FIGS. 17 and 18.

The damping force adjusting type shock absorber 1 is mounted between the spring and the unspring of the suspension device of the vehicle. When the vehicle is traveling, if vibration in the vertical direction occurs due to unevenness on the road surface, the shock absorber 1 is displaced so that the piston rod 6 extends and contracts from the outer cylinder 3, and is attenuated by the damping force generation mechanism 25. Generates force to damp vehicle vibrations.

At this time, the damping force generation mechanism 25 variably adjusts the damping force by changing the back pressure of the main valve 39 during the expansion stroke of the piston rod 6, and on the other hand, during the compression stroke of the piston rod 6. The damping force can be variably adjusted by adjusting the thrust (control current) and changing the valve opening pressure of the pilot valve 55.

Here, during the extension stroke of the piston rod 6, the hydraulic oil on the cylinder upper chamber 2A side is pressurized by the movement of the piston valve 5 in the cylinder 2. The pressure of the hydraulic oil in the cylinder upper chamber 2 </ b> A acts on the back pressure chamber 46 through the passage 173 including the orifice 176, the communication passage 70, the pilot chamber 33, and the communication passage 150.

At this time, the pressure receiving area (S1) of the main valve 39 is an area (S2 + S3) obtained by adding the area (S2) of the annular surface 138A of the main valve 39 and the area (S3) of the outer peripheral surface 139B of the annular seat portion 139. ), The cross-sectional area of the back pressure chamber 46 by the plane perpendicular to the axis, in other words, the area (S1 = S2 + S3-S4) obtained by subtracting the area (S4) of the annular upper end surface 137B of the flange portion 137.

When the pilot valve 55 is moved by the pressure in the pilot chamber 33, the seat portion 48 of the first valve portion 55d of the pilot valve 55 is detached from the valve seat 49 of the main valve 39 and is opened, and the pilot chamber 33 (= back The hydraulic oil in the pressure chamber 46) flows through a path "communication passage 55b of the flange portion 55e of the pilot valve 55" ⇒ "communication passage 39B and communication passage 39A formed in the main valve 39 extending in the vertical direction" It flows into the cylinder lower chamber 2B.

At this time, the hydraulic oil corresponding to the piston rod 6 withdrawn from the cylinder 2 flows from the reservoir 4 into the cylinder lower chamber 2B by opening the check valve 16 of the base valve 10. In addition, the pressure receiving area of the pilot valve 55 is the sectional area (area on the valve body back pressure chamber side) of the operating pin 79 (shaft portion) by a plane perpendicular to the axis from the area inside the seat portion 48 on the lower surface (area on the valve seat side) ) Minus the area.

On the other hand, when the control current of the linear solenoid 54 is low during the contraction stroke of the piston rod 6, the force by which the pilot spring 172 pushes up the operating pin 79 exceeds the thrust of the linear solenoid 154. Thereby, the seat portion 48 of the first valve portion 55d of the pilot valve 55 is detached from the valve seat 49 of the main valve 39, and the first valve portion 55d of the pilot valve 55 is opened. As a result, the hydraulic oil in the cylinder lower chamber 2B is referred to as “the passage 39A of the main valve 39” → “the communication passage 55b of the flange portion 55e of the pilot valve 55” → “the communication passage 70” → “the passage 173 including the orifice 176”. It flows through the path and flows into the cylinder upper chamber 2A.

Further, in the contraction stroke of the piston rod 6, when the control current of the linear solenoid 54 is high, the thrust of the linear solenoid 154 exceeds the force of pushing up the pilot spring 172. As a result, the seat portion 48 of the second valve portion 55d of the pilot valve 55 is seated on the valve seat 49 of the main valve 39, whereby the first valve portion 55d of the pilot valve 55 is closed.

In this state, since the main valve 39 and the pilot valve 55 are considered to be integrated, the valve opening pressure of the main valve 39 (main valve portion 27) depends on the thrust of the plunger 153 generated by the linear solenoid 154. The pressure receiving area of the main valve 39 at this time is an area obtained by subtracting the cross-sectional area of the third shaft hole 44 of the piston case 21 from the area inside the seat portion 139.

The hydraulic oil that has entered the cylinder 2 by the piston rod 6 reaches the valve opening pressure of the relief valve 18 of the base valve 10 when the pressure in the cylinder lower chamber 2B reaches, and the relief valve 18 opens. It flows to the reservoir 4.

Next, the fail operation state when the control current is cut off due to the disconnection of the coil of the linear solenoid 154, the failure of the control device, or waiting for a signal will be described with reference to FIG.

When the control current to the linear solenoid 154 is cut off, the thrust of the plunger 153 and the operating pin 79 disappears, so that the pilot valve 55 is retracted away from the pilot chamber 33 by the spring force of the fail spring 169. As a result, the seat portion 48 of the first valve portion 55d of the pilot valve 55 is disengaged from the valve seat 49 of the main valve 39, and the first valve portion 55d of the pilot valve 55 is opened to open the pilot chamber 33. .

When the pilot valve 55 moves backward, the second valve portion 55c formed on the outer periphery of the flange portion 55e of the pilot valve 55 is brought into contact with the pilot valve downstream side seat portion 80, and the communication path 39B is closed by the second valve portion 55c. It is done. In this state, the cylinder upper chamber 2 </ b> A and the cylinder lower chamber 2 </ b> B include the “passage 173 including the orifice 176”, “communication passage 70”, “communication passage 55 b of the flange portion 55 e of the pilot valve 55”, “failure valve 81 The communication is made via the “opening” and the “passage 39A of the main valve 39”.

For example, during the extension stroke, the hydraulic fluid on the cylinder upper chamber 2A side is pressurized by the movement of the piston valve 5 in the cylinder 2. The hydraulic oil in the cylinder upper chamber 2 </ b> A flows into the passage 173 including the orifice 176 and the communication passage 70. Therefore, the hydraulic oil is “passage 173 including orifice 176” → “communication passage 70” → “upstream chamber 51a” → “communication passage 55b of flange portion 55e of pilot valve 55” → “downstream chamber 51b” → “pilot valve It flows into the cylinder lower chamber 2B through a path of “opening 80a of the downstream seat member 80” → “opening 81a of the fail valve 81” → “passage 39A of the main valve 39”.

Here, when the pressure in the upstream chamber 51a and the downstream chamber 51b reaches a predetermined pressure, the fail valve 82 is deformed to open a flow path between the fail valve seat member 81 and the pressure according to the first embodiment. It is the same. The fail valve 82 is provided with an opening / closing part 82a capable of opening and closing a seat hole 81a provided in the fail valve seat member 81 as in the first embodiment. The opening / closing part 82a is formed to be elastically deformable and is opened at a predetermined pressure or more. It functions as an operating relief valve.

According to the present embodiment, a sufficient damping force can be obtained in the fail operation state as in the first embodiment. In addition, since the damping force generation mechanism 25 is disposed in the cylinder 2, it is possible to further improve the miniaturization.

In each of the embodiments described above, hydraulic oil is used as the working fluid, but other fluids may be used. Moreover, it can be used not only as a vehicle but also as a damping force adjusting type shock absorber in other industrial fields.

As described above, the present invention provides a damping force adjustment type shock absorber having a control valve assembly that generates a damping force by controlling a flow of hydraulic oil generated by sliding of a piston in a cylinder. The valve body portion and the valve chamber that accommodates the valve body portion, and an actuator that controls the valve body portion by the thrust of the solenoid, the valve body portion divides the valve chamber into an upstream chamber and a downstream chamber and A first valve portion that opens and closes a first flow port connected to an upstream chamber and an upstream region upstream thereof; a second valve portion that opens and closes a second flow port connected to a downstream chamber and a downstream region downstream thereof; and an upstream chamber A communication passage that communicates with the downstream chamber, a fail passage that bypasses the second valve portion and connects the downstream chamber and the downstream region, and a fail valve disposed in the fail passage. It is.

According to the present invention, at the time of transition to the fail operation state, or at the time of return from the fail operation state, the fluctuation of the fluid force due to the change of the flow of hydraulic oil acting on the first valve portion can be reduced, and the first valve portion is vibrated Can be suppressed.

In addition, this invention is not limited to the above-mentioned Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 ... Buffer, 2 ... Cylinder, 4 ... Reservoir, 5 ... Piston, 6 ... Piston rod, 10 ... Base valve, 25 ... Damping force generation mechanism, 27 ... Main valve part, 28 ... Pilot valve part, 29 ... Fail valve 36, main body, 38 ... pilot body, 39 ... main valve, 51 ... valve chamber, 51a upstream chamber, 51b ... downstream chamber, 53 ... plunger, 55 ... pilot valve, 55d ... first valve portion, 55c ... first 2 valve portions, 55b ... communication passageway, 69 ... pilot valve outer diameter passage portion, 80 ... pilot valve downstream seat member, 81 ... fail valve seat member, 82 ... fail valve, 154 ... solenoid portion.

Claims (11)

A cylinder filled with a working fluid; a piston slidably fitted in the cylinder; a piston rod connected to the piston and extending to the outside of the cylinder; and a reservoir connected to the cylinder And a damping force adjusting type shock absorber having a control valve assembly that generates a damping force by controlling a flow of a working fluid generated by sliding of the piston in the cylinder,
The control valve assembly includes a valve body portion, a valve chamber that houses the valve body portion, and an actuator that controls the valve body portion by thrust of a solenoid,
The valve body section divides the valve chamber into an upstream chamber and a downstream chamber, and opens and closes a first flow port connected to the upstream chamber and an upstream region upstream thereof, the downstream chamber, and A second valve portion that opens and closes a second flow port connected to the downstream downstream region, a communication passage that communicates the upstream chamber and the downstream chamber, and the downstream chamber and the downstream region bypassing the second valve portion And a fail valve arranged in the fail passage. A damping force adjusting type shock absorber. The damping force adjustable shock absorber according to claim 1,
In a state where the actuator is operating, a working fluid is allowed to flow to the reservoir through the first valve portion, the upstream chamber, the communication path, the downstream chamber, the second valve portion, and the downstream region.
When the operation of the actuator is stopped, the reservoir passes through the first valve portion, the upstream chamber, the communication passage, the downstream chamber, the fail passage in which the fail valve is opened, and the downstream region. A damping force adjusting type shock absorber, characterized in that a working fluid is allowed to flow through. A cylinder filled with a working fluid; a piston slidably fitted in the cylinder; a piston rod connected to the piston and extending to the outside of the cylinder; and a reservoir connected to the cylinder And a damping force adjusting type shock absorber having a control valve assembly that generates a damping force by controlling a flow of a working fluid generated by sliding of the piston in the cylinder,
The control valve assembly includes a main valve portion and a pilot valve portion,
The pilot valve portion includes a valve body portion and a valve chamber that houses the valve body portion, and an actuator that controls the valve body portion by a thrust of a solenoid,
The valve body section divides the valve chamber into an upstream chamber and a downstream chamber, and opens and closes a first flow port connected to the upstream chamber and an upstream region upstream thereof, the downstream chamber, and A second valve portion that opens and closes a second flow port connected to the downstream downstream region, a communication passage that communicates the upstream chamber and the downstream chamber, and the downstream chamber and the downstream region bypassing the second valve portion And a fail valve disposed in the fail passage,
The main valve portion includes a cylinder side region communicated with the cylinder and a main valve that opens and closes a connection between the reservoir side region communicated with the reservoir, and the opening degree of the main valve is the upstream of the pilot valve portion. A damping force adjusting type shock absorber which is adjusted by the pressure of the chamber. The damping force adjustable shock absorber according to claim 3,
In a state where the actuator is operating, a working fluid is allowed to flow to the reservoir through the first valve portion, the upstream chamber, the communication path, the downstream chamber, the second valve portion, and the downstream region.
When the operation of the actuator is stopped, the reservoir passes through the first valve portion, the upstream chamber, the communication passage, the downstream chamber, the fail passage in which the fail valve is opened, and the downstream region. A damping force adjusting type shock absorber, characterized in that a working fluid is allowed to flow through. In the damping force adjustment type shock absorber according to claim 1 or claim 3,
Damping force characterized in that the cross-sectional area through which hydraulic oil at the inlet upstream of the first flow port opened and closed by the first valve portion passes is set larger than the total cross-sectional area of the communication passage 55b. Adjustable shock absorber. In the damping force adjustment type shock absorber according to claim 1 or claim 3,
The damping force adjusting type shock absorber according to claim 1, wherein the communication passage communicating the upstream chamber and the downstream chamber is a communication passage formed in the first valve portion itself. In the damping force adjustment type shock absorber according to claim 1 or claim 3,
The damping force adjusting type shock absorber according to claim 1, wherein the communication path connecting the upstream chamber and the downstream chamber is a communication path formed outside the first valve portion separately from the first valve portion. In the damping force adjustment type shock absorber according to claim 1 or claim 3,
The first valve portion and the second valve portion are integrally formed, and the communication path is formed between the first valve portion and the second valve portion. Type shock absorber. The damping force adjustment type shock absorber according to claim 8,
The valve body including the first valve portion and the second valve portion is formed in a disc shape, the first valve portion is formed in the vicinity of the central portion of the valve body, and the valve body is formed around the outer periphery of the valve body. A damping force adjusting type shock absorber, wherein a second valve portion is formed, and a plurality of the communication passages are formed at predetermined angles in an annular region between the first valve portion and the second valve portion. . The damping force adjustable shock absorber according to claim 9,
The second valve portion is formed of an annular convex portion formed on the outer periphery of the valve body, and the second convex opening is opened and closed by the annular convex portion. In the damping force adjustment type shock absorber according to claim 1 or claim 3,
The second valve portion is formed of a ball valve and a spring, and a damping force adjusting type shock absorber.

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