JP6814644B2 - Damping force adjustable shock absorber - Google Patents

Description

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

In shock absorbers used in vehicles such as automobiles, sensors detect running conditions such as road surface irregularities and vehicle body movements, and a linear solenoid changes the operating pressure of the valve that opens and closes the oil passage provided in the shock absorber piston. As a result, a semi-active suspension system (damping force adjustment type shock absorber) that adjusts the damping force according to the running condition is widely adopted.

The semi-active suspension system has the advantages of lower power consumption, simpler structure and more compact structure than the active suspension system in which the actuator is operated by a power source, so that it is relatively inexpensive and has excellent mountability.

As a background technology in this technical field, for example, there is a technology such as Patent Document 1. Patent Document 1 describes a damping force-adjustable shock absorber as follows: "The extension side passage and the compression side passage that communicate the extension side chamber and the compression side chamber, the extension side valve body that opens and closes the extension side passage, and the compression side valve that opens and closes the compression side passage. The body, the extension side back pressure chamber that biases the extension side valve body, the compression side back pressure chamber that biases the compression side valve body, and the compression side resistance chamber that communicates with the extension side back pressure chamber via the extension side resistance element. A communication passage that communicates with the compression side back pressure chamber via an element, an extension side pressure introduction passage that communicates between the extension side chamber and the compression side back pressure chamber, and a compression side pressure introduction passage that communicates between the compression side chamber and the extension side back pressure chamber. The extension side is provided with an adjustment passage connected to the communication passage and an electromagnetic pressure control valve provided in the adjustment passage to control the upstream pressure of the adjustment passage, and the extension side valve body is attached by the pressure of the extension side back pressure chamber. It is stated that the load is made larger than the compression side load that urges the compression side valve body by the pressure of the compression side back pressure chamber. "

Further, Patent Document 2 states that "a cylinder, a piston that is slidably inserted into the cylinder and divides the inside of the cylinder into an extension side chamber and a compression side chamber, and a damping passage that communicates the extension side chamber and the compression side chamber. And the pressure chamber that communicates with the extension side chamber and the compression side chamber, and the extension side pressure chamber and the compression side chamber that are movably inserted into the pressure chamber and communicate the pressure chamber with the extension side chamber. A shock absorber provided with a free piston that is partitioned from a compression side pressure chamber and a damping force adjusting unit that is provided in the damping passage and can change the resistance given to the flowing liquid flow is disclosed.

JP 2015-72047 JP-A-2015-94366

By the way, in the semi-active suspension system (damping force adjustment type shock absorber), noise vibration due to a change in the flow of the working fluid (oil) during operation may occur depending on the arrangement of the control valve built in the shock absorber and the structure of the oil passage. It can be a problem.

In the structure described in Patent Document 1, the working fluid in the stretching process first passes through the introduction path below the piston from the stretching side chamber above, and changes the direction of the flow upward to the electromagnetic pressure above the piston. It heads toward the control valve, passes through the electromagnetic control valve, then changes the direction of the flow again, heads downward, and flows into the compression side chamber. Therefore, when the direction of the flow is changed as described above, it tends to be a cause of noise and vibration due to the occurrence of loss.

Further, in the structure of Patent Document 2, the number of built-in control valves is large and the path of the hydraulic oil is complicated, and the hydraulic oil flows from the outside to the inside of the shock absorber during operation and then flows to the outside again. , Noise and vibration are likely to occur.

Therefore, an object of the present invention is to provide a novel damping force-adjustable shock absorber capable of suppressing noise and vibration caused by a change in the flow of the working fluid inside the shock absorber during operation as much as possible.

In view of the above circumstances, the present invention has a cylinder in which a working fluid is sealed, a piston that is slidably fitted in the cylinder and divides the inside of the cylinder into one side chamber and another side chamber, and one end thereof. A piston rod connected to the piston and the other end extending to the outside of the cylinder, and a piston rod provided on the piston, which controls the flow of working fluid from the one side chamber to the other side chamber by the movement of the piston and dampening force. A damping force-adjustable shock absorber comprising a damping valve mechanism for generating the above, wherein the damping valve mechanism includes a main valve that regulates the flow of working fluid from the one side chamber to the other side chamber, and the main valve. A piston chamber urged in the valve closing direction, an introduction path resistance element that restricts the flow of the working fluid in the one side chamber and leads to the pilot chamber, and a working fluid that has flowed into the pilot chamber through the introduction path resistance element. It has a control valve capable of adjusting the pressure in the pilot chamber by controlling the flow to the other side chamber, and the control valve is driven by the linear solenoid and the linear solenoid in the axial direction of the piston. It has a mover, a valve body provided at one end of the mover, and a valve seat on which the valve body is seated and opens and closes a communication passage connecting the pilot chamber and the other side chamber. toward the side chamber to the other side chamber, the introduction path resistive element, the valve body, are arranged in order of the valve seat, Ri Do a unidirectional flow without the working fluid returning from the other side chamber side to the one side chamber side A flow path connecting the one side chamber and the other side chamber is formed between the piston and the main valve, and the flow path is a contact portion of the valve body from the introduction path resistance element to the valve seat. Has a first flow path formed including a first vector parallel to the arrangement direction of the one side chamber and the other side chamber, and when viewed from a direction perpendicular to the arrangement direction, the flow The path is characterized in that the first flow path is formed so as not to overlap with another flow path .

According to the present invention, it is possible to realize a novel damping force adjustment type shock absorber capable of suppressing noise vibration due to a change in the flow of the working fluid inside the shock absorber during operation as much as possible.

Issues, configurations and effects other than those described above will be clarified by the description of the following embodiments.

It is a figure which shows the schematic structure of the damping force adjustment type shock absorber for the semi-active suspension to which this invention is applied. It is sectional drawing which shows the damping force generation mechanism of the damping force adjustment type shock absorber of Example 1. FIG. FIG. 2 is an enlarged cross-sectional view of the vicinity of the pilot valve portion and the main valve portion in the normal operating state of the damping force generating mechanism shown in FIG. FIG. 3 is a view of the main valve shown in FIG. 3 as viewed from above in FIG. FIG. 3 is a view of the pilot valve shown in FIG. 3 as viewed from above in FIG. It is a figure which looked at the pilot valve 2nd valve part seat member shown in FIG. 3 from the upper part of FIG. FIG. 3 is a view of the fail valve seat member shown in FIG. 3 as viewed from above in FIG. FIG. 3 is a view of the fail valve shown in FIG. 3 as viewed from above in FIG. FIG. 2 is an enlarged cross-sectional view of the vicinity of the pilot valve portion and the main valve portion in the fail operating state of the damping force generating mechanism shown in FIG. FIG. 5 is an enlarged cross-sectional view of the vicinity of the pilot valve portion and the main valve portion in the normal operating state of the damping force generating mechanism in which the shape of the pilot valve valve seat portion is changed in the first embodiment. FIG. 5 is an enlarged cross-sectional view of the vicinity of the pilot valve portion and the main valve portion in the normal operating state of the damping force generating mechanism of the second embodiment. FIG. 5 is an enlarged cross-sectional view of the vicinity of the pilot valve portion and the main valve portion in the fail operating state of the damping force generating mechanism of the second embodiment. It is a figure which looked at the pilot valve 2nd valve part seat member of Example 2 from the upper part of FIG. FIG. 5 is an enlarged cross-sectional view of the vicinity of the pilot valve portion and the main valve portion in the fail operating state of the damping force generating mechanism of the third embodiment. It is a figure which looked at the main valve of Example 3 from the upper part of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the following embodiments, and various modifications and applications are included in the technical concept of the present invention. Is also included in that range. In each drawing, the same components are designated by the same reference numerals, and the detailed description of overlapping portions will be omitted.

The damping force-adjustable shock absorber according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 9. FIG. 1 shows the overall configuration of the damping force adjusting shock absorber 1 for the semi-active suspension. As shown in FIG. 1, the damping force adjusting shock absorber 1 according to the present embodiment includes a cylinder 2, a piston 5 sliding in the cylinder 2, a piston rod 6 connected to the piston 5, a reservoir 4, and a damping force generation. It is composed of a mechanism 7 and the like, and is mounted between two relative movable members such as a spring upper (vehicle body) side and a spring lower (wheel side) side of a vehicle suspension device (not shown).

The damping force adjusting type shock absorber 1 has a double cylinder structure in which a cylinder 2 and an outer cylinder 3 are provided on the outside thereof, and a reservoir 4 is formed between the cylinder 2 and the outer cylinder 3.

A piston 5 is slidably interposed in the cylinder 2, and the inside of the cylinder 2 is divided into a cylinder upper chamber 2A and a cylinder lower chamber 2B by the piston 5.

The piston rod 6 is connected to the piston 5 via the piston case 20, and the end portion of the piston rod 6 opposite to the piston 5 passes through the cylinder upper chamber 2A, passes through the oil seal 9, and is outside the cylinder 2. It is protruding. On the lower end side of the cylinder 2, a base valve 10 that separates the cylinder lower chamber 2B and the reservoir 4 is provided.

The base valve 10 is provided with passages 15 and 16 for communicating the cylinder lower chamber 2B and the reservoir 4. A check valve 17 that allows only fluid to flow from the reservoir 4 to the cylinder lower chamber 2B is provided in the passage 15, and the pressure of the fluid on the cylinder lower chamber 2B side reaches a predetermined pressure in the passage 16. A relief valve 18 is provided which sometimes opens the valve and relieves the valve to the reservoir 4 side.

As the hydraulic fluid, hydraulic oil is sealed in the cylinder 2, and hydraulic oil and gas are sealed in the reservoir 4. Further, in FIG. 1, reference numeral 3A is a bottom cap joined to the lower end of the outer cylinder 3, and reference numeral 19 is a mounting eye joined to the bottom cap 3A.

FIG. 2 is an enlarged cross-sectional view of the vicinity of the piston 5 and the damping force generating mechanism 7 of FIG. 1, showing the detailed structure of the damping force generating mechanism of this embodiment. Further, FIG. 3 is an enlarged cross-sectional view of the vicinity of the pilot valve portion and the main valve portion in the normal operating state of the damping force generating mechanism 7 shown in FIG.

The piston 5 has a substantially cylindrical shape, has an inner flange portion 5A extending inward at the lower end portion, and is fixed to the lower side (cylinder lower chamber 2B side) of the substantially cylindrical piston case 20 arranged in the cylinder 2. Will be done. Inside the piston case 20, a first shaft hole 21 and a second shaft hole 23 whose diameters decrease stepwise from the cylinder upper chamber 2A side are provided in order, and similarly, the diameter stepwise from the cylinder lower chamber 2B side. The third shaft hole 26 and the fourth shaft hole 22 are provided in this order.

A valve seat member 31 is provided at the lower end of the piston case 20 so that the main valve 41, which will be described later, is detached and seated. The valve seat member 31 has a cylindrical shaft portion 35, a flange portion 32 formed at the lower end of the shaft portion 35, and a screw portion 33 formed on the outer peripheral surface of the shaft portion 35.

Further, the valve seat member 31 is fixed to the piston case 20 by screwing the screw portion 33 into the screw portion 24 formed in the third shaft hole 26 of the piston case 20. Further, the inner flange portion 5A of the piston 5 is sandwiched between the lower end portion end surface of the piston case 20 and the flange portion 32 of the valve seat member 31, and the piston 5 is fixed to the lower end portion of the piston case 20.

The upper end of the piston case 20 is closed by a coil cap 30 having a substantially cylindrical shape. The coil cap 30 has a screw portion 36 formed on the outer peripheral surface of the upper end portion, and the screw portion 36 is screwed into the screw portion 27 formed at the upper end of the first shaft hole 21 of the piston case 20 to form a piston case. It is fixed at 20. Further, the coil cap 30 is formed with an annular seal groove along the outer peripheral surface of the lower end portion, and the O-ring 81 mounted in the seal groove seals the coil cap 30 with the first shaft hole 21 of the piston case 20. ..

One end of the piston rod 6 is connected to the center of the upper end of the coil cap 30, and the other end of the piston rod 6 passes through the cylinder upper chamber 2A and is further attached to the upper ends of the cylinder 2 and the outer cylinder 3. It is inserted into the rod guide 8 and the oil seal 9 (see FIG. 1), and extends to the outside of the cylinder 2.

Then, the flow of hydraulic oil between the upper chamber 2A of the cylinder and the lower chamber 2B of the cylinder, which is generated by the movement (expansion and contraction) of the piston rod 6, is controlled in the piston case 20 and eventually in the cylinder 2. , A damping force generating mechanism 7 for generating a damping force is provided. The damping force generation mechanism 7 has a main valve portion 40 that controls valve closing by the pressure of the pilot chamber 42, which will be described later, and a pilot valve portion 50 that controls the pressure of the pilot chamber 42 by the linear solenoid 70.

The main valve portion 40 includes a main valve 41, a valve seat member 31 on which the main valve 41 is seated, and a compression coil spring 65 that urges the main valve 41 in the valve closing direction.

Since the shape of the main valve 41 is shown in FIG. 4, this will also be described with reference to this. The main valve 41 is formed in a substantially bottomed cylindrical shape having a recess, and the inside is provided with a large diameter portion 41D having a large diameter on the release side (upper side) and a small diameter portion 41C having a small diameter on the bottom side in a stepped manner. .. A groove 41A is provided on the outermost diameter side of the step portion 41F formed thereby, and a communication passage 41B for communicating between the groove and the center is provided.

As shown in FIG. 3, a flange portion 41H (outer flange) is formed at the lower end of the main valve 41. An annular seat portion 39 is formed on the lower end surface of the flange portion 41H of the main valve 41 so as to be detached from and seated on the valve seat 38 of the valve seat member 31.

When the seat portion 39 is seated on the valve seat 38 of the valve seat member 31, an annular chamber 84 is formed between the lower end portion of the piston case 20, the valve seat member 31 and the main valve 41. A plurality of passages 34 for communicating the annular chamber 84 and the cylinder upper chamber 2A are provided at the lower end of the piston case 20.

Further, in the main valve 41, the cylindrical outer peripheral surface 88 is slidably inserted into the fourth shaft hole 22 of the piston case 20, and the outer peripheral surface of the flange portion 41H slides into the third shaft hole 26 of the piston case 20. It is inserted as possible. As a result, an annular back pressure chamber 46 is formed between the main valve 41 and the third shaft hole 26.

A valve seat 48 is provided at the bottom of the recess of the main valve 41 so that the annular seat portion 62 formed on the pilot valve 51, which will be described later, is detached and seated. Further, a communication passage 41G communicating with the cylinder lower chamber 2B is provided inside the valve seat 48.

A compression coil spring 65 that applies a set load is installed between the piston case 20 and the upper end side of the main valve 41. As a result, the piston case 20 is urged downward, that is, in the valve closing direction.

Next, the pilot valve portion 50 will be described. The pilot valve portion 50 is a pilot valve second valve portion seat member 53, a fail valve support member 54, a fail valve 55, a fail valve seat member 56, and a fail valve fixed, which are arranged in order from the bottom on the upper surface of the step portion 41F of the main valve 41. A portion 58, a pilot valve 51 arranged inside the small diameter portion 41C of the main valve 41, an operating pin 71 in which the pilot valve 51 is fixed to the lower end, a fail spring 59 acting in the valve opening direction, a pilot spring 61, and a linear solenoid. It is composed of 70.

Since the shape of the pilot valve 51 is shown in FIG. 5, this will also be described with reference to this. The pilot valve 51 has a substantially cylindrical bottomed shape, and the cylinder has a disk portion 51A, a bottomed center hole 51C, and a communication hole 51G communicating from the bottom to the bottom, and a seat portion 62 is provided at the bottom of the cylinder. It is formed and has an annular convex portion 51B on the outer peripheral portion of the disc portion 51A on the side opposite to the sheet portion 62. The seat portion 62 is formed so as to have a "first valve portion" capable of opening and closing a flow path with the valve seat portion 48 formed in the main valve 41. The diameter of the seat portion 62 is set to be smaller than the outer diameter of the operating pin 71 described later.

The outer diameter portion of the annular convex portion 51B is set so that the pilot valve 51 can operate by sliding the small diameter portion 41C of the main valve 41 or through a minute gap.

Further, the valve chamber in which the pilot valve 51 is arranged is separated by the disk portion 51A into an upstream chamber 51D on the upstream side and a downstream chamber 51E on the downstream side. The disk portion 51A of the pilot valve 51 is formed with a plurality of communication passages 52 that communicate the upstream chamber 51D and the downstream chamber 51E. The annular convex portion 51B functions as a "second valve portion" described later. Further, a fail spring 59 of the compression coil spring is arranged between the lower end of the disk portion 51A and the bottom portion of the recess of the main valve 41.

Since FIG. 6 shows the shape of the pilot valve second valve portion seat member 53, this will also be described with reference to it. As shown in FIG. 6, the pilot valve second valve seat member 53 is formed in the shape of a disk having a hole 53A in the center, and the tip of the annular convex portion 51B of the pilot valve 51 is in contact with the disk. Arranged so as to be in contact with and separated from each other. As a result, a second valve portion that opens and closes the flow path of the communication passage 41B provided in the main valve 41 is formed. Further, on the outer diameter side, a space 53B is provided between the main valve 41 and the large diameter portion 41D.

Since the shape of the fail valve seat member 56 is shown in FIG. 7, this will also be described with reference to it. As shown in FIG. 7, the fail valve seat member 56 is formed in a disk shape having holes 56C having the same diameter as the operation pin 71 described later in the central portion, and has a shape provided with a plurality of communication holes 56A. The outer diameter side has a disk shape in which a space 56B is provided between the main valve 41 and the large diameter portion 41D.

Since the shape of the fail valve 55 is shown in FIG. 8, this will also be described with reference to it. As shown in FIG. 8, the fail valve 55 has a disk shape and is formed so as to be elastically deformable. The outside is sandwiched between the fail valve support member 54 and the fail valve seat member 56 described later, and the upstream pressure acts on the upper surface of the fail valve 55 by the communication hole 56A provided in the fail valve seat member 56, and the pressure is equal to or higher than a predetermined pressure. , It functions as a relief valve that opens a flow path by the communication hole 56A. Further, on the outer diameter side, a space 56B is provided between the main valve 41 and the large diameter portion 41D.

The fail valve support member 54 is provided between the fail valve 55 and the pilot valve second valve portion seat member 53, has a disk shape with a hole in the center, and the outside of the fail valve 52 is the opening / closing portion of the fail valve 55. It is held so as to be a fulcrum of operation. On the outer diameter side, a space 54B is provided between the main valve 41 and the large diameter portion 41D.

The fail valve fixing portion 58 is installed on the cylinder upper chamber 2A side of the fail valve seat member 56, has a disk shape, and is provided with a communication passage 58A at the center and a communication passage 58B at the outer edge. By fixing the fail valve fixing portion 58 to the main valve 41, the pilot valve second valve portion seat member 53, the fail valve support member 54, the fail valve 55, and the fail valve seat member 56 are fixed to the main valve 41. Will be done. A space (communication passage) 58B is provided on the outer diameter side of the fail valve fixing portion 58 with the large diameter portion 41D of the main valve 41.

A valve chamber 63 is formed inside the fourth shaft hole 22 and the annular convex portion 29 of the piston case 20 and above the fail valve fixing portion 58. The valve chamber 63 is communicated with the piston upper chamber 2A by an introduction communication passage 25 provided in the piston case 20. The introduction passage 25 is composed of a resistance element in which flow path resistance is generated by an orifice throttle or the like.

Further, the valve chamber 63 is provided on the outer edge side of each of the fail valve fixing portion 58, the fail valve seat member 56, the fail valve 55, the fail valve support member 54, the fail valve 55, and the pilot valve second valve portion seat member 53. The spaces 58B, 56B, 55B, 54B, and 53B communicate with the groove 41A provided in the main valve 41, and the communication passage 41B communicates with the small diameter portion 41C of the main valve 41. Further, when the second valve portion of the pilot valve 51 is open, the pilot valve 51 communicates with the upstream chamber 51D, the communication passage 52, and the downstream chamber 51E. A pilot chamber 42 of the main valve 41 is formed in the chambers from the valve chamber 63 to the downstream chamber 51E, and a force in the valve closing direction acts on the main valve 41 due to the pressure of the pilot chamber 42.

The linear solenoid 70 has a case member 74 in which a plunger bore is formed, and a core 76 in which a recess 76B into which a lower end portion of the plunger 73 is slidably fitted is formed. The case member 74 is formed in a substantially cylindrical shape, and a flange portion 74A is formed on the outer periphery of the upper end portion. Further, the upper end portion of the case member 74 is fitted into a recess formed on the lower end surface of the coil cap 30. Further, the case member 74 has a sleeve 78 mounted on the outer peripheral surface thereof, and the lower end portion of the sleeve 78 is fitted into the second shaft hole 23 of the piston case 20. As a result, the case member 74 is positioned coaxially with respect to the center line of the piston case 20.

On the other hand, the core 76 is formed in a substantially cylindrical shape, and the flange portion 76A is formed on the outer periphery of the lower end portion. Further, in the core 76, the flange portion 76A is fitted into the second shaft hole 23 of the piston case 20, and the flange portion 76A is formed between the second shaft hole 23 and the fourth shaft hole 22 of the piston case 20. By abutting against the annular convex portion 29, the piston case 20 is positioned in the vertical direction.

The inner peripheral surface of the lower end of the sleeve 78 is fitted to the outer peripheral surface of the core 76. Further, the sleeve 78 is positioned in the vertical direction with respect to the piston case 20 by abutting the lower end portion against the flange portion 76A of the core 76. Further, an O-ring 83 is arranged between the case member 74 and the sleeve 78, and an O-ring 83 is arranged between the sleeve 78 and the fourth shaft hole 22 of the piston case 20 to seal each other.

On the other hand, the actuating pin 71 is movably supported in the vertical direction by a pair of bushes 85 and 86 assembled to the case member 74 and the core 76. Further, the lower end of the operating pin 71 is attached to and fitted to the bottom of the central hole 51C provided in the pilot valve 51. Further, inside the operating pin 71, there is a shaft hole 71B that communicates with the communication hole 51G of the pilot valve 51, the upper side of the operating pin 71, and the lower side of the pilot valve 51.

A retaining ring 60 is attached to the annular groove formed on the outer peripheral surface of the operating pin 71. The upper end of the pilot spring 61 whose lower end is sandwiched between the main valve 41 and the compression coil spring 65 is engaged with the retaining ring 60. As a result, the operating pin 71 is urged upward by the spring force of the pilot spring 61.

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

The damping force adjusting shock absorber 1 is mounted between the spring and the unsprung of the suspension device of the vehicle. When the vehicle travels, when vibration occurs in the vertical direction due to unevenness of the road surface or the like, the damping force adjusting shock absorber 1 is displaced so that the piston rod 6 extends and contracts from the outer cylinder 3, and the damping force generating mechanism A damping force is generated at 7 to buffer the vibration of the vehicle. (See Fig. 1)
At this time, the damping force generating mechanism 7 can adjust the thrust (control current) of the linear solenoid 70 to control the force acting on the main valve 41, so that the damping force can be variably adjusted.

First, the time of the extension stroke of the piston rod 6 will be described. During the stretching process, the hydraulic oil on the cylinder upper chamber 2A side is pressurized by the movement of the piston 5 in the cylinder 2.

A case where a current is applied to the linear solenoid 70 will be described. The hydraulic oil from the cylinder upper chamber 2A flows through the introduction passage 25, the valve chamber 63, each space 58B, 56B, 55B, 54B, 53B, the groove 41A of the main valve 41, and the communication passage, as shown in the flow of F1 shown in FIG. It flows to the cylinder lower chamber 2B through 41B, the upstream chamber 51D of the pilot valve 51, the pilot valve communication passage 52, the downstream chamber 51E, the first valve portion, and the communication passage 41G.

At this time, when the pressure of the pilot chamber 42 is P, the force of approximately (S1-S2) × P is applied to the pilot valve 51 from the area S1 due to the outer diameter of the operating pin 71 and the area S2 of the seat portion 62. It works in the valve opening direction of the first valve part. Further, a force Fsp in the valve opening direction by the fail spring 59 and the pilot spring 61 acts. On the other hand, the linear solenoid 70 generates Fsol in the valve closing direction. Therefore, the pressure P can be adjusted by controlling the force Fsol generated by the linear solenoid 70 from the force balance equation (S1-S2) × P + Fsp = Fsol. That is, if the solenoid thrust (control current) is large, the opening of the first valve portion becomes small, the pressure in the pilot chamber 42 rises, and if the solenoid thrust (control current) is small, the opening of the first valve portion becomes large. , The pressure in the pilot chamber 42 decreases.

In the main valve 41, the pressure of the pilot chamber 42 is applied to the area generated by the diameter difference between the diameter of the seat portion 62 of the pilot valve 51 and the diameter difference of the fourth shaft hole 22 of the piston case 20, and a force in the valve closing direction acts thereby. On the other hand, the pressure in the piston upper chamber 2A exerts a force in the valve opening direction due to the area generated by the diameter difference between the diameter of the flange portion 41H of the main valve 41 and the diameter of the valve seat portion of the main valve 41. The force of the compression coil spring 65 in the valve closing direction of the main valve 41 is also working, and it operates by balancing these. That is, by controlling the pressure in the pilot chamber 42, the opening of the main valve 41 is controlled, and the pressure in the cylinder upper chamber 2A is further controlled to generate an appropriate damping force.

When the main valve 41 is opened, it flows from the cylinder upper chamber 2A into the cylinder lower chamber 2B through the valve seat portion, as shown by the flow of F2. At this time, the amount of hydraulic oil discharged from the cylinder 2 by the piston rod 6 flows from the reservoir 4 into the cylinder lower chamber 2B by opening the check valve 17 of the base valve 10.

Next, the contraction stroke of the piston rod 6 will be described. When the control current of the linear solenoid 70 is low, the force pushing up the operating pin 71 by the pilot spring 61 exceeds the thrust of the linear solenoid 70. As a result, the seat portion 62 of the first valve portion of the pilot valve 51 is separated from the valve seat 48 provided in the main valve 41, and the first valve portion of the pilot valve 51 is opened.

As a result, the hydraulic oil in the lower chamber 2B of the cylinder is the communication passage 41G of the main valve 41, the communication passage 52 of the pilot valve 51, the communication passage 41B of the main valve 41, the groove portion 41A, the pilot valve second valve portion seat member 53, and the fail. Introduced through the spaces 53B, 54B, 55B, 56B, 58B and valve chamber 63 provided at the outer edges of the valve 55, the fail valve support member 54, the fail valve 55, the fail valve seat member 56, and the fail valve fixing portion 58. It flows into the cylinder upper chamber 2A through the communication passage 25.

When the control current of the linear solenoid 70 is a high current, the thrust of the linear solenoid 70 exceeds the pushing force of the pilot spring 61. As a result, the seat portion 62 of the pilot valve 51 is seated on the valve seat 48 provided on the main valve 41, so that the first valve portion of the pilot valve 51 is closed.

In this state, the main valve 41 and the pilot valve 51 are considered to be integrated, so the valve opening pressure of the main valve 41 depends on the thrust of the plunger 73 generated by the linear solenoid 70. At this time, the main valve 41 has a force in the valve closing direction due to the diameter difference between the diameter of the third shaft hole 26 of the piston case 20 and the diameter of the seat portion 39 due to the pressure on the cylinder lower chamber 2B side, and the fourth valve. A force acts in the valve opening direction due to the difference in diameter between the diameter of the shaft hole 22 and the outer diameter of the operating pin 71, but the valve is opened by overcoming the solenoid thrust, and the cylinder is opened from the cylinder lower chamber 2B via the seat portion 39. Hydraulic oil flows into the upper chamber 2A.

Then, the hydraulic oil for the amount of the piston rod 6 entering the cylinder 2 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 the valve opening pressure, and the relief valve 18 opens. It will be distributed to the reservoir 4.

Next, a fail operation state when the control current is cut off due to a disconnection of the coil of the linear solenoid 70, a failure of the control device, a signal waiting, or the like will be described with reference to FIG.

When the control current to the linear solenoid 70 is cut off, the thrust of the plunger 73 and the operating pin 71 is lost. Therefore, the direction in which the pilot valve 51 is separated from the valve seat 48 provided in the main valve 41 by the spring force of the fail spring 59. Move to. As a result, the seat portion 62 of the first valve portion of the pilot valve 51 is separated from the valve seat 48, and the first valve portion of the pilot valve 51 is opened.

When the pilot valve 51 moves upward, the second valve portion formed on the annular convex portion 51B of the pilot valve 51 is brought into contact with the pilot valve second valve portion seat member 53, and the second valve portion causes the communication passage 41B. Closed.

In this state, in the stretching process, the hydraulic oil in the cylinder upper chamber 2A is pressurized, and pressure is applied to the fail valve 55 through the communication hole 56A of the fail valve seat member 56. When this pressure reaches a predetermined pressure, the fail valve 55 is deformed so as to open a flow path between the fail valve and the seat member 56. The fail valve 55 is formed so as to be elastically deformable so that the communication hole 56A of the fail valve seat member 56 can be opened and closed, and functions as a relief valve that opens the valve at a predetermined pressure or higher.

As shown in F1 of FIG. 9, the flow from the cylinder upper chamber 2A at this time is the introduction communication passage 25, the center hole 58A of the fail valve fixing portion 58, the communication hole 56A of the fail valve seat member 56, and the fail valve 55. Cylinder lower chamber through the opening, the central hole 53A of the pilot valve second valve seat member 53, the upstream chamber 51D of the pilot valve 51, the pilot valve communication passage 52, the downstream chamber 51E, the first valve part, and the communication passage 41G. It flows to 2B.

In this case, in the pilot chamber 42, the upstream side of the communication hole 56A communicates with the valve chamber 63, and the downstream side of the fail valve 55 has a relatively low pressure. Of these, a force in the valve closing direction acts on the main valve 41 mainly due to the force generated by the upstream high-pressure portion.

As a result, the pressure of the pilot chamber 42 is applied to the main valve 41 by the diameter difference between the outer diameter of the main valve 41 (the diameter of the fourth shaft hole 22 of the piston case 20) and the outer diameter of the operating pin 71, and the valve is closed. Power works. Since the fail valve 55 acts as a relief valve and rises in the pressure of the pilot chamber 42, a force in the valve closing direction acts on the main valve 41, and a sufficient damping force can be obtained.

According to the present embodiment, the introduction communication passage 25 having an orifice throttle (resistance element), the pilot valve portion 50 (valve body), from the cylinder upper chamber 2A (one side chamber) to the cylinder lower chamber 2B (other side chamber). The valve seats 48 are arranged in order along the direction of the pilot flow path from the introduction communication passage 25 to the communication passage 41G of the main valve 41 via the pilot chamber 42, and the working fluid is not returned from the cylinder upper chamber 2A to the cylinder lower chamber. Since the flow is unidirectional toward 2B, noise and vibration caused by changes in the flow of the working fluid can be suppressed as much as possible.

In addition, the structure is such that a predetermined damping force can be generated even during failure, and the flow between the upper chamber and the lower chamber of the piston does not bend more than necessary, so the loss is small and it is unlikely to be a cause of sound vibration. It can be a damping force adjustment type shock absorber.

In the present embodiment, an example in which the fail valve 55 is composed of a disc-shaped spring as shown in FIG. 8 is shown, but if the flow of hydraulic oil does not change, a ball valve and a spring that urges the ball valve in the closing direction are used. It may be a ball valve type valve to be formed.

Further, the seat portion 62 of the pilot valve 51 may be formed in a tapered shape as in the modified example shown in FIG. In this case, the flow of the first valve portion has a shape along the taper, the collision of the flow is less likely to occur, and the generation of vibration noise can be suppressed. Similarly, although not shown, the same effect can be obtained even if the valve seat 48 side has a tapered shape.

Further, the pilot flow path from the introduction communication passage 25 to the communication passage 41G of the main valve 41 via the pilot chamber 42 is between the introduction communication passage 25 and the contact portion of the pilot valve portion 50 with the valve seat 48. It has a first flow path formed including a first vector parallel to the arrangement direction of the cylinder upper chamber 2A and the cylinder lower chamber 2B, and is in a direction perpendicular to the arrangement direction of the cylinder upper chamber 2A and the cylinder lower chamber 2B. From the viewpoint, it is desirable to form the first flow path so that it does not overlap with other flow paths. That is, it is desirable that a flow path (flow path for returning the working fluid) of a vector parallel to the arrangement direction of the cylinder lower chamber 2B and the cylinder upper chamber 2A (a vector in the direction opposite to the first vector) is not formed. ..

Further, it is more desirable that the angle of the bent portion of the pilot passage 25 to the contact portion of the pilot valve portion 50 with the valve seat 48 is 90 degrees or an obtuse angle.

Further, between the introduction communication passage 25 and the contact portion of the pilot valve portion 50 with the valve seat 48, the components in the direction perpendicular to the arrangement direction of the cylinder upper chamber 2A and the cylinder lower chamber 2B of the first flow path are described. Is desirable to have a unidirectional flow from the outside to the inside in the cylinder 2. In each case, a return portion for the flow of the working fluid is not provided.

Next, the damping force-adjustable shock absorber of the second embodiment of the present invention will be described with reference to FIGS. 11 to 13. In the present embodiment, the configuration of the pilot valve portion 50 is different from that of the first embodiment, and the other configurations are the same as those of the first embodiment. Therefore, in the following description, the description overlapping with the first embodiment will be omitted. FIG. 11 shows a normal operating state, and FIG. 12 shows a fail operating state.

The configuration of the pilot valve portion 50 of the present embodiment will be described. The pilot valve portion 50 has a pilot valve second valve portion seat member 153 arranged on the upper surface of the step portion 41F of the main valve 41, a pilot valve 51 arranged inside the small diameter portion 41C of the main valve 41, and a pilot valve 51 at the lower end. It is composed of a fixed operating pin 71, a fail spring 59 acting in the valve opening direction, a pilot spring 61, and a linear solenoid 70.

Since FIG. 13 shows the shape of the pilot valve second valve portion seat member 153, this will also be described with reference to it. As shown in FIG. 13, the pilot valve second valve seat member 153 is formed in the shape of a disk having a central hole 153A in the center, and the tip of the annular convex portion 51B of the pilot valve 51 is formed on the disk. A second valve portion that opens and closes the flow path of the communication passage 41B (see FIG. 4) provided in the main valve 41 is formed by abutting and separating from each other. Further, on the outer diameter side, a space 153B is provided between the main valve 41 and the large diameter portion 41D. The diameter of the central hole 153A is larger than the outer diameter of the operating pin 71, and a throttle passage 155 is formed between them, which acts as a flow path resistance. Further, the pilot valve second valve seat member 153 is fixedly arranged on the main valve 41.

A valve chamber 63 is formed inside the fourth shaft hole 22 and the annular convex portion 29 (see FIG. 2) of the piston case 20 and above the pilot valve second valve portion seat member 153. The valve chamber 63 is communicated with the piston upper chamber 2A by an introduction communication passage 25 (see FIG. 2) provided in the piston case 20. The introduction passage 25 is composed of a resistance element in which flow path resistance is generated by an orifice throttle or the like. Further, the valve chamber 63 communicates with the groove 41A provided in the main valve 41 by the communication passage (space) 153B provided on the outer edge side of the pilot valve second valve portion seat member 153, and further communicates with the groove 41A provided in the main valve 41 by the communication passage 41B. It communicates with the small diameter portion 41C of the valve 41. Further, when the second valve portion of the pilot valve 51 is open, the pilot valve 51 communicates with the upstream chamber 51D, the communication passage 52, and the downstream chamber 51E. The pilot chamber 42 of the main valve 41 is formed in the chambers from the valve chamber 63 to the downstream chamber 51E.

Other configurations are the same as in the first embodiment. The specific operation of the damping force adjustment type shock absorber in the present embodiment having the above configuration will be described. First, the operation in the normal state will be described with reference to FIG.

During operation in the normal state, the damping force generating mechanism 7 can adjust the thrust (control current) of the linear solenoid 70 to control the force acting on the main valve 41, so that the damping force can be variably adjusted.

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 5 in the cylinder 2.

The flow of hydraulic oil when a current is applied to the linear solenoid 70 will be described. The hydraulic oil from the cylinder upper chamber 2A is the flow of F1 shown in FIG. 11, as shown in the flow of F1, the introduction passage 25, the valve chamber 63, the passage 53B, the groove portion 41A of the main valve 41, the communication passage 41B, and the upstream chamber of the pilot valve 51. It flows to the cylinder lower chamber 2B through 51D, the communication passage 52 of the pilot valve, the downstream chamber 51E, the first valve portion, and the communication passage 41G. At the same time, as shown by the dotted line, the flow from the valve chamber 63 also flows through the throttle passage 155 to the upstream chamber 51D of the pilot valve.

By controlling the thrust of the linear solenoid 70 as in the first embodiment, the pressure in the pilot chamber 42 is controlled, and the damping force can be controlled.
Next, a fail operation state when the control current is cut off due to a disconnection of the coil of the linear solenoid 70, a failure of the control device, a signal waiting, or the like will be described with reference to FIG.

When the control current to the linear solenoid 70 is cut off, the thrust of the plunger 73 and the operating pin 71 is lost. Therefore, the direction in which the pilot valve 51 is separated from the valve seat 48 provided in the main valve 41 by the spring force of the fail spring 59. Move to. As a result, the seat portion 62 of the first valve portion of the pilot valve 51 is separated from the valve seat 48 provided in the main valve 41, and the first valve portion of the pilot valve 51 is opened.

When the pilot valve 51 moves upward, the second valve portion formed on the annular convex portion 51B of the pilot valve 51 is brought into contact with the pilot valve second valve portion seat member 153, and the second valve portion causes the communication passage 41B ( (See FIG. 4) is closed.

In this state, the hydraulic oil in the cylinder upper chamber 2A is pressurized in the stretching process. Then, from the cylinder upper chamber 2A, the introduction connecting passage 25, the throttle passage 155, the upstream chamber 51D of the pilot valve 51, the pilot valve connecting passage 52, the downstream chamber 51E, the first valve portion, and the connecting passage 41G pass under the cylinder. It flows to room 2B. Since the flow is throttled at the central hole 153A, the pressure upstream of that is the pressure on the downstream side of the introduction passage 25, and the pressure downstream is substantially the same as the pressure on the downstream side of the main valve 41. A valve chamber 63 on the upstream side and a pilot chamber 42 of the main valve 41 are formed upstream of the central hole 153A.

As a result, the pressure of the pilot chamber 42 is applied to the main valve 41 by the diameter difference between the outer diameter of the main valve 41 (the diameter of the fourth shaft hole 22 of the piston case 20) and the outer diameter of the operating pin 71, and the valve is closed. Power works. Since the central hole 153A acts as a throttle and rises in the pressure of the pilot chamber 42, a force acts on the main valve 41 in the valve closing direction, and a sufficient damping force can be obtained.

According to the present invention, the same effect as that of the first embodiment can be obtained, and the number of parts is further reduced, so that the cost can be reduced.

Next, the damping force-adjustable shock absorber of the third embodiment of the present invention will be described with reference to FIGS. 14 and 15. In the present embodiment, the pilot valve portion 50 is configured as a normally closed type, and other configurations are the same as those in the first embodiment. Therefore, in the following description, the description overlapping with the first embodiment will be omitted. FIG. 14 shows a fail operation state.

The structure of the main valve 41 of the present embodiment will be described. The main valve 41 of the present embodiment is different from the first and second embodiments in that it does not have a structure such as a groove or a continuous passage inside.

The main valve 41 is formed in a substantially bottomed cylindrical shape having a recess. A flange portion 41H (outer flange) is formed at the lower end of the main valve 41. An annular seat portion 39 is formed on the lower end surface of the flange portion 41H of the main valve 41 so as to be detached from and seated on the valve seat 38 of the valve seat member 31.

When the seat portion 39 is seated on the valve seat 38 of the valve seat member 31, an annular chamber 84 is formed between the lower end portion of the piston case 20, the valve seat member 31 and the main valve 41. A plurality of passages 34 for communicating the annular chamber 84 and the cylinder upper chamber 2A are provided at the lower end of the piston case 20.

Further, in the main valve 41, the cylindrical outer peripheral surface 88 is slidably inserted into the fourth shaft hole 22 of the piston case 20, and the outer peripheral surface of the flange portion 41H slides into the third shaft hole 26 of the piston case 20. It is inserted as possible. As a result, an annular back pressure chamber 46 is formed between the main valve 41 and the third shaft hole 26.

A valve seat 48 is provided at the bottom of the recess of the main valve 41 so that the annular seat portion 62 formed on the pilot valve 51, which will be described later, is detached and seated. Further, a communication passage 41G communicating with the cylinder lower chamber 2B is provided inside the valve seat 48.

A compression coil spring 65 that applies a set load is installed between the piston case 20 and the upper end side of the main valve 41. As a result, the piston case 20 is urged downward, that is, urged in the valve closing direction.

Next, the configuration of the pilot valve unit 50 will be described. The pilot valve portion 50 is composed of a pilot valve 51 arranged inside the recess of the main valve 41, an operating pin 71 to which the pilot valve 51 is fixed at the lower end, a pilot spring 61 acting in the valve closing direction, and a linear solenoid 70. ..

The pilot valve 51 has a substantially cylindrical bottomed shape, has a bottomed center hole 51C at the center of the cylinder, and further has a communication hole 51G communicating from the bottom to the bottom, and a seat portion 62 is formed at the bottom of the cylinder. The outer diameter of the cylinder is set smaller than the inner diameter of the recess of the main valve 41. The seat portion 62 is formed so as to have a "pilot valve portion" capable of opening and closing a flow path with the valve seat portion 48 formed in the main valve 41. The diameter of the seat portion 62 is set to be smaller than the outer diameter of the operating pin 71, and a force acts in the direction of opening the pilot valve portion by the pressure of the valve chamber 63.

With the above configuration, the valve chamber 63 formed above the valve seat portion 48 acts as a pilot chamber of the main valve 41. Further, an introduction communication passage 25 is provided between the valve chamber 63 and the piston upper chamber 2A, and an orifice serving as a flow path resistance is provided as needed.

Further, a pilot spring 61 of a compression coil spring is arranged between the upper end of the pilot valve 51 and the annular convex portion of the main valve 41, and acts in the direction of closing the pilot valve portion.

Further, a plunger of the linear solenoid 70 is fixed to the operating pin 71, and is arranged so that when a current is applied, a force is generated upward in the drawing, that is, in the direction of opening the pilot valve portion. That is, the pilot valve portion 50 is configured as a normally closed valve.

The specific operation of the damping force adjustment type shock absorber according to the present embodiment having the above configuration will be described.

First, the operation in the normal state will be described. During normal operation, the damping force generating mechanism 7 variably adjusts the damping force by changing the pressure in the pilot chamber of the main valve 41 during the extension stroke of the piston rod 6, while during the contraction stroke of the piston rod 6. The damping force can be variably adjusted by adjusting the thrust (control current) of the linear solenoid 70.

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 5 in the cylinder 2.

The flow of hydraulic oil when a current is applied to the linear solenoid 70 will be described. The hydraulic oil from the cylinder upper chamber 2A flows to the cylinder lower chamber 2B through the introduction passage 25, the valve chamber 63, the pilot valve portion, and the central hole 41G of the main valve 41, as in the flow of F1 shown in FIG.

Similar to the first and second embodiments, the pressure of the valve chamber 63 serving as the pilot chamber is controlled by controlling the thrust of the linear solenoid 72, and the damping force can be controlled.

Next, a fail operation state when the control current is cut off due to a disconnection of the coil of the linear solenoid 70, a failure of the control device, a signal waiting, or the like will be described with reference to FIG.

When the control current to the linear solenoid 70 is cut off, the thrust of the plunger 73 and the operating pin 71 is lost. Therefore, the direction in which the pilot valve 51 closes the valve seat 48 provided in the main valve 41 by the spring force of the pilot spring 61. Move to. As a result, the seat portion 62 of the first valve portion of the pilot valve 51 is seated on the valve seat 48 provided in the main valve 41, and the pilot valve portion is closed.

In this state, the hydraulic oil in the cylinder upper chamber 2A is pressurized in the stretching process. Then, oil flows from the cylinder upper chamber 2A into the introduction passage 25 and the valve chamber 63. As a result, when the force in the valve opening direction of the pilot valve portion due to the pressure in the valve chamber 63 overcomes the valve closing direction by the pilot spring 61, the valve is opened, and the oil flows to the cylinder lower chamber 2B through the communication passage 41G.

The valve chamber 63 on the upstream side acts as the pilot chamber 42 of the main valve 41, but since the pressure in the valve chamber 63 rises when a flow occurs, the pressure of the valve chamber 63 is applied to the main valve 41 of the operating pin 71. A force acts in the valve closing direction due to the diameter difference from the outer diameter. A force acts on the main valve 41 in the valve closing direction, and a sufficient damping force can be obtained.

According to the configuration of the present embodiment, the pilot valve 51 can be a normally closed valve, the same effect as in the first and second embodiments can be obtained, and the fail valve and the throttle portion can be eliminated. Since the number of parts is smaller, the structure can be made at low cost.

The present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to those having all the described configurations. Further, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Further, it is possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

1 ... shock absorber (damping force adjustable shock absorber), 2 ... cylinder, 4 ... reservoir, 5 ... piston, 6 ... piston rod, 7 ... damping force generation mechanism, 10 ... base valve, 20 ... piston case, 25 ... introduction Communication passage, 31 ... valve seat member, 40 ... main valve part, 41 ... main valve, 50 ... pilot valve part, 51 ... pilot valve, 53 ... pilot valve second valve part seat member, 55 ... fail valve, 56 ... fail Valve seat member, 63 ... valve chamber, 70 ... linear solenoid, 73 ... plunger.

Claims (11)

A cylinder filled with working fluid and
A piston that is slidably fitted in the cylinder and divides the inside of the cylinder into a concubine and a concubine.
A piston rod with one end connected to the piston and the other end extending outside the cylinder.
A damping force adjusting shock absorber provided on the piston and provided with a damping valve mechanism that controls the flow of a working fluid from the one concubine to the other concubine by the movement of the piston to generate a damping force.
The damping valve mechanism includes a main valve that regulates the flow of working fluid from the one side chamber to the other side chamber.
A pilot chamber that urges the main valve in the valve closing direction, and
An introduction path resistance element that limits the flow of working fluid in the concubine and leads to the pilot chamber,
It has a control valve capable of adjusting the pressure in the pilot chamber by controlling the flow of the working fluid flowing into the pilot chamber through the introduction path resistance element to the other side chamber.
The control valve includes a linear solenoid and
A mover driven by the linear solenoid in the axial direction of the piston,
A valve body provided at one end of the mover and
It has a valve seat on which the valve body is seated and opens and closes a communication passage connecting the pilot chamber and the other side chamber.
The introduction path resistance element, the valve body, and the valve seat are arranged in this order from the one side chamber to the other side chamber , and the working fluid flows in one direction without returning from the other side chamber side to the one side chamber side. Do Ri,
A flow path connecting the one side chamber and the other side chamber is formed between the piston and the main valve.
The flow path is formed from the introduction path resistance element to the contact portion of the valve body with the valve seat, including a first vector parallel to the arrangement direction of the one side chamber and the other side chamber. Has a first flow path
A damping force-adjustable shock absorber characterized in that the flow path is formed so that the first flow path does not overlap with another flow path when viewed from a direction perpendicular to the arrangement direction . The damping force adjusting shock absorber according to claim 1 .
The flow path is a damping force-adjustable shock absorber having a bent portion at an angle of 90 degrees or an obtuse angle between the introduction path resistance element and the contact portion of the valve body with the valve seat. The damping force adjusting shock absorber according to claim 1 .
In the flow path , the component in the direction perpendicular to the arrangement direction of the first flow path is from the outside in the cylinder between the introduction path resistance element and the contact portion of the valve body with the valve seat. A damping force adjustment type shock absorber characterized by a one-way flow toward the inside. The damping force adjusting shock absorber according to any one of claims 1 to 3 .
The control valve is a damping force adjusting shock absorber characterized by being a normally open valve that opens when the linear solenoid is not energized. The damping force adjusting shock absorber according to claim 4 .
The control valve includes an urging means for urging the valve body in the valve opening direction and
It has a valve chamber for accommodating the valve body in the pilot chamber, and has a valve chamber.
The valve body divides the valve chamber into an upstream chamber and a downstream chamber.
It has an inflow passage opening / closing portion that opens / closes an inflow passage from the one side chamber side of the pilot chamber to the upstream chamber.
A fail passage that bypasses the inflow passage opening / closing portion and communicates between the upstream side of the pilot chamber and the upstream chamber.
A damping force-adjustable shock absorber comprising a fail valve body that opens and closes the fail passage. The damping force adjusting shock absorber according to claim 5 .
The valve body is a damping force adjusting shock absorber having a communication passage that communicates the upstream chamber and the downstream chamber. The damping force adjusting shock absorber according to claim 5 or 6 .
A damping force adjusting shock absorber characterized in that the fail valve body is a disc valve. The damping force adjusting shock absorber according to claim 5 or 6 .
A damping force adjusting shock absorber characterized in that the fail valve body is a ball valve. The damping force adjusting shock absorber according to claim 4 .
The control valve includes an urging means for urging the valve body in the valve opening direction and
It has a valve chamber for accommodating the valve body in the pilot chamber, and has a valve chamber.
The valve body divides the valve chamber into an upstream chamber and a downstream chamber.
It has an inflow passage opening / closing portion that opens / closes an inflow passage from the one side chamber side of the pilot chamber to the upstream chamber.
A fail passage that bypasses the inflow passage opening / closing portion and communicates between the upstream side of the pilot chamber and the upstream chamber.
A damping force adjustable shock absorber comprising a resistance element that limits the flow of the fail passage. The damping force adjusting shock absorber according to any one of claims 1 to 9 .
A damping force adjusting shock absorber characterized in that the seating surface of the valve body with the valve seat or the seating surface of the valve seat with the valve body has a tapered shape. The damping force adjusting shock absorber according to any one of claims 1 to 10 .
The main valve is a damping force adjusting shock absorber having a substantially bottomed cylindrical shape having a concave portion forming a part of the pilot chamber.

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