JP2022190948A - Attenuation force adjustable buffer - Google Patents

Abstract

To reduce the entire size to make an installation space small, and reduce the number of components to improve workability for assembly.SOLUTION: In a cylinder 2, a flow path 8 through which hydraulic oil flows between another side chamber B and a reservoir chamber C is provided outside the cylinder 2, and in the flow path 8, a damping force generation mechanism 9 is provided for generating damping force by regulating the flow of hydraulic oil caused by the movement of a piston 3 by the operation of a rod-side actuator 10 and a bottom-side actuator 11.SELECTED DRAWING: Figure 3

Description

TECHNICAL FIELD The present disclosure relates to a damping force adjustable shock absorber suitable for damping vibrations of buildings, automobiles, railway vehicles, and the like.

Shock absorbers are generally used to suppress vibrations of buildings due to earthquakes and vibrations of automobiles and railway vehicles when they are running. The shock absorber includes a cylinder in which a working fluid such as hydraulic oil is enclosed, a piston inserted in the cylinder to divide the inside of the cylinder into a rod-side chamber and an anti-rod-side chamber, and a piston connected to the piston to extend outside the cylinder. an extending piston rod.

In addition, there is a shock absorber in which a reservoir chamber is formed between the inner cylinder and the outer cylinder by making the cylinder a double structure of the inner cylinder and the outer cylinder. In addition, a damping force generating mechanism that generates an adjusted damping force is provided between the rod-side chamber and the reservoir chamber (Patent Document 1).

JP 2017-211062 A

By the way, in the invention of Patent Document 1, the cylinder has a double structure in order to provide the damping force generating mechanism. As a result, the size of the cylinder is increased, so there is a problem that a large space is required for installing the shock absorber. Moreover, there is also a problem that the number of parts increases and the assembling workability deteriorates.

An object of one embodiment of the present invention is to provide a damping force adjustable shock absorber that is made compact to reduce the installation space and that can be assembled with a reduced number of parts to improve assembly workability. be.

An embodiment of the present invention comprises a cylinder in which a working fluid is sealed, a piston inserted into the cylinder to define one side chamber and the other side chamber in the cylinder, and a piston connected to the piston to move the cylinder. a piston rod extending to the outside; a body portion inserted into the other side chamber in the cylinder and provided so as to define the inside of the cylinder into the other side chamber and a reservoir chamber for ensuring volume; A flow path through which the working fluid flows between the reservoir chamber and a damping force generating mechanism that regulates the flow of the working fluid generated by the movement of the piston and generates a damping force by the operation of an actuator provided in the flow path. And prepare.

According to one embodiment of the present invention, the installation space can be reduced by miniaturizing the whole. In addition, the number of parts can be reduced to improve assembly workability.

1 is a perspective view showing a damping force adjustable shock absorber according to a first embodiment of the present invention; FIG. FIG. 2 is an external view of the damping force adjustable shock absorber of FIG. 1; FIG. 3 is a cross-sectional view of the damping force adjustable shock absorber as seen from the direction of arrows III-III in FIG. 2; 4 is an enlarged cross-sectional view showing a damping force generating mechanism and the like in FIG. 3; FIG. FIG. 5 is a cross-sectional view showing the damping force generating mechanism and the like in a non-powered state from the same position as in FIG. 4; FIG. 4 is a characteristic diagram showing damping force characteristics of the damping force adjustable shock absorber in a powered state and damping force characteristics of the damping force adjustable shock absorber in a non-powered state; FIG. 6 is a cross-sectional view showing a damping force generating mechanism and the like according to a second embodiment of the present invention; FIG. 8 is a cross-sectional view showing the damping force generating mechanism and the like in a non-powered state from the same position as in FIG. 7;

Hereinafter, the damping force adjustable shock absorber according to the embodiment of the present invention is a semi-active type that generates a damping force adjusted by the operation of an electromagnetic actuator, and this damping force suppresses the vibration acting on the building due to an earthquake. An example of use as a damping force adjustable shock absorber will be described in detail with reference to the accompanying drawings.

1 to 6 show a first embodiment of the invention. In this first embodiment, there is another flow path provided in the body portion that communicates the other side chamber with the reservoir chamber, and a predetermined flow path that is provided in the other flow path and the pressure of the other side chamber is higher than the pressure of the reservoir chamber. and a relief valve that opens when the value reaches a value of , and the actuator is provided on the other side chamber side and operates so that the working fluid flows when no power is supplied. and a second actuator that operates to restrict the flow of the working fluid and opens the valve when the pressure in the other side chamber reaches a predetermined value lower than the pressure in the reservoir chamber.

1 to 3, the damping force adjustable shock absorber 1 includes a cylinder 2, a piston 3, a piston rod 4, a body portion 6, a passage 8, a damping force generating mechanism 9, a first relief passage 13, a first It is configured including two relief flow paths 14 , a first relief valve 15 and a second relief valve 16 .

The cylinder 2 is formed as a bottomed single cylindrical body (monotube). Hydraulic oil or the like is sealed in the cylinder 2 as a working fluid. The working fluid is not limited to hydraulic oil, and for example, water mixed with additives can be used.

One end of the cylinder 2 is an open end 2A, and a piston rod 4, which will be described later, protrudes from the open end 2A. On the other hand, the other end of cylinder 2 is closed by bottom cap 2B. Further, the cylinder 2 is provided with an all-around crimped portion 2C projecting inwardly at an intermediate portion near the bottom cap 2B. This all-circumference caulked portion 2C fixes a body portion 6, which will be described later. As means for fixing the body portion 6, in addition to the full circumference crimping portion 2C, partial crimping such as four or six points in the circumferential direction may be used.

2 A of open ends are diameter-reduced and formed so that it may protrude to an inner peripheral side like the whole circumference crimped part 2C. As a result, the open end 2A fixes a rod guide 5, which will be described later, and the like. Further, the bottom cap 2B of the cylinder 2 is attached with a bottom-side mounting bracket 2D that is mounted on the building structure via a bracket (both not shown).

The cylinder 2 is provided with two mounting holes 2E and 2F at positions sandwiching the crimped portion 2C (body portion 6). The mounting holes 2E and 2F penetrate the cylinder 2 in the radial direction. A rod-side actuator 10 of a damping force generating mechanism 9, which will be described later, is attached to the mounting hole 2E communicating with the other side chamber B, which will be described later. A bottom-side actuator 11 is attached to an attachment hole 2F communicating with a reservoir chamber C, which will be described later.

The piston 3 is arranged in the cylinder 2 so as to be axially movable (slidable). The piston 3 divides the inside of the cylinder 2 into one side chamber A on the side of the piston rod 4 and the other side chamber B on the side opposite to the piston rod 4 (the side of the body portion 6). The piston 3 has communication passages 3A and 3B for circulating hydraulic oil between one side chamber A and the other side chamber B when the piston 3 is displaced within the cylinder 2, and hydraulic oil circulating through the communication passages 3A and 3B. Disc valves 3C, 3D are provided to limit the flow of the

The piston rod 4 has one end connected to the piston 3 and the other end protruding from one end of the cylinder 2 via a rod guide 5 . Attached to the other end of the piston rod 4 is a rod-side attachment bracket 4A that is attached to the building structure via a bracket (both not shown).

The body portion 6 is made of a thick disk inserted into the other side chamber B in the cylinder 2 and fixed by a crimped portion 2C on the entire circumference. The body portion 6 divides the inside of the cylinder 2 into the other side chamber B and the reservoir chamber C for ensuring the volume. The body portion 6 is provided with a first relief channel 13 , a second relief channel 14 , a first relief valve 15 and a second relief valve 16 . The reservoir chamber C is an oil chamber for releasing hydraulic oil corresponding to the entry volume of the piston rod 4 when the piston rod 4 contracts (retraction stroke).

The free piston 7 is located inside the cylinder 2 and is slidably fitted between the bottom cap 2B and the body portion 6 . Thus, the free piston 7 defines a space between the bottom cap 2B and the body portion 6 into a reservoir chamber C on the body portion 6 side and a gas chamber D on the bottom cap 2B side. The gas chamber D is filled with gas to allow expansion and contraction of the reservoir chamber C (movement of the free piston 7).

Next, the structure, function, etc. of the flow path 8 and the damping force generating mechanism 9, which are characteristic parts of the present invention, will be described.

The flow path 8 is a passage for circulating hydraulic oil between the other side chamber B and the reservoir chamber C. As shown in FIG. The flow path 8 is constituted by an axial hole 10B of the rod-side actuator 10, an axial hole 11B of the bottom-side actuator 11, and an in-pipe passage 12A of the connecting pipe 12, which will be described later.

As shown in FIGS. 4 and 5, the damping force generating mechanism 9 includes a rod-side actuator 10 as a first actuator and a bottom-side actuator 11 as a second actuator. The damping force generating mechanism 9 regulates the flow of hydraulic oil caused by the movement of the piston 3 and generates a damping force by the operation of the rod side actuator 10 and the bottom side actuator 11 provided in the flow path 8 .

The rod-side actuator 10 is provided in the cylinder 2 in communication with the other-side chamber B. As shown in FIG. The rod-side actuator 10 is configured as an electromagnetic actuator that uses magnetic force to move a plunger 10C, which will be described later.

The rod-side actuator 10 includes a cylindrical cylindrical portion 10A with a lid, one end of which is attached to the mounting hole 2E of the cylinder 2 and the other end of which is closed, and a shaft extending in the axial direction within the cylindrical portion 10A. A hole 10B, a plunger 10C slidably provided in the shaft hole 10B, a magnet 10D provided on the outer peripheral side of the plunger 10C, and a magnet 10D positioned on the other side of the cylindrical portion 10A and having the same inner diameter as the shaft hole 10B. and a spring 10F that is provided in the shaft hole 10B and biases the plunger 10C toward the other side (opposite side to the reservoir chamber C) in the valve opening direction. The plunger 10</b>C also serves as a valve element that adjusts the flow area of the flow path 8 .

Further, in the cylinder portion 10A of the rod-side actuator 10, a connection hole 10G is provided through the cylinder portion 10A in the radial direction at a position on one side of the plunger 10C in the fully open position (the position shown in FIG. 5). ing. The cylindrical portion 10A is attached to the cylinder 2 so that the connection hole 10G faces the bottom side actuator 11. As shown in FIG. One end of a connection pipe 12, which will be described later, is inserted into the connection hole 10G.

Here, the rod-side actuator 10 operates so that the hydraulic oil flows when there is no power supply (for example, when it is electrically stopped due to a power failure or malfunction). Specifically, when the rod-side actuator 10 is not powered, as shown in FIG. 5, the plunger 10C is moved to the other side by the biasing force of the spring 10F. As a result, the shaft hole 10B communicates with the other side chamber B and the connecting pipe 12 (intra-pipe passage 12A).

On the other hand, the rod-side actuator 10 generates magnetic force by supplying power to the coil 10E, and appropriately moves the plunger 10C against the spring 10F. Thereby, the plunger 10C can adjust the flow area between the axial hole 10B and the connection pipe 12 (in-tube passage 12A).

Moreover, since the rod-side actuator 10 is installed outside the cylinder 2, it can be formed by a simple work of mounting it in the mounting hole 2E of the cylinder 2, an electromagnetic actuator with a simple shape, and a simple wiring work. .

Next, the bottom-side actuator 11 is provided in the cylinder 2 while communicating with the reservoir chamber C. As shown in FIG. Like the rod-side actuator 10, the bottom-side actuator 11 is formed as an electromagnetic actuator, and includes a tubular portion 11A, a shaft hole 11B, a plunger 11C, a magnet 11D, a coil 11E, a spring 11F, and a connection hole 11G. . However, the bottom-side actuator 11 differs from the rod-side actuator 10 in two points: the position of the spring 11F is changed and the restriction passage 11H is provided.

A spring 11F of the bottom-side actuator 11 is provided on the other side of the shaft hole 11B and biases the plunger 11C toward one side (reservoir chamber C side) in the valve closing direction. A throttle passage 11H is provided through the plunger 11C in the axial direction. When the piston rod 4 is contracted and the piston 3 is moved to the other side with the plunger 11C in the valve closing position shown in FIG. A damping force is generated by restricting the flow rate of the hydraulic oil flowing into the chamber C.

Here, the bottom side actuator 11 operates so as to suppress the flow of hydraulic oil when no power is supplied. Specifically, the bottom-side actuator 11 moves the plunger 11C to the closed valve position on one side by the biasing force of the spring 11F when no power is supplied. As a result, the plunger 11C blocks the connection between the reservoir chamber C and the connecting pipe 12 (intra-tube passage 12A). Further, in the closed position of the plunger 11C, damping force can be generated by restricting the flow rate of hydraulic oil flowing from the other side chamber B to the reservoir chamber C by the throttle passage 11H.

Further, when the pressure in the other side chamber B reaches a predetermined value lower than the pressure in the reservoir chamber C, the plunger 11C of the bottom side actuator 11 opens against the force of the spring 11F. In addition, since the bottom side actuator 11 is installed outside the cylinder 2 like the rod side actuator 10, it can be easily mounted in the mounting hole 2F of the cylinder 2, has a simple shape, and is a simple electromagnetic actuator. It can be formed by wiring work. The predetermined value mentioned above is a value that is appropriately determined according to the performance, setting, and usage environment of the damping force adjustable shock absorber.

The connection pipe 12 is made of a tubular body having an inner pipe passage 12</b>A inside, and constitutes a part of the flow path 8 . The connection pipe 12 is positioned outside the cylinder 2 and arranged to extend linearly along the outer peripheral surface of the cylinder 2 . One end of the connection pipe 12 is inserted into the connection hole 10G of the rod-side actuator 10 and the other end is inserted into the connection hole 11G of the bottom-side actuator 11 . As a result, the in-pipe passage 12A communicates the other side chamber B and the reservoir chamber C in cooperation with the shaft hole 10B of the rod side actuator 10 and the shaft hole 10B of the bottom side actuator 11 .

A first relief channel 13 as another channel is provided in the body portion 6 and communicates the other side chamber B and the reservoir chamber C with each other. The first relief channel 13 has a valve seat 13A on the reservoir chamber C side. As shown in FIG. 3, the second relief channel 14 is provided in the body portion 6 at a position different from that of the first relief channel 13, and communicates the other side chamber B and the reservoir chamber C with each other. The second relief channel 14 has a valve seat 14A on the other side chamber B side.

A first relief valve 15 as a relief valve is provided in the first relief flow path 13 . The first relief valve 15 has a valve portion 15A that is seated on and off the valve seat 13A, and is urged in the seating direction by a spring 15B. The first relief valve 15 opens when the pressure in the other side chamber B reaches a predetermined value higher than the pressure in the reservoir chamber C. Specifically, the first relief valve 15 opens against the spring 15B when the piston rod 4 contracts at a high speed.

A second relief valve 16 is provided in the second relief flow path 14 . The second relief valve 16 has a valve portion 16A that is seated on and off the valve seat 14A, and is biased in the seating direction by a spring 16B. The second relief valve 16 opens when the pressure in the reservoir chamber C reaches a predetermined value higher than the pressure in the other side chamber B. Specifically, the second relief valve 16 opens against the spring 16B when the piston rod 4 expands at a high speed.

The damping force adjustable shock absorber 1 according to the first embodiment has the configuration as described above, and the operation thereof will now be described. This operation is an example of the operation of the damping force adjustable shock absorber 1, and the content of damping force control is not limited to this.

In the damping force adjustable shock absorber 1, a bottom side mounting bracket 2D provided on the cylinder 2 is mounted on the building structure, and a rod side mounting bracket 4A provided on the piston rod 4 is mounted on the building structure. be done. In this state, when the structure vibrates due to an earthquake, the damping force adjustable shock absorber 1 expands and contracts. By this extension operation and contraction operation, the damping force generating mechanism 9 and the like of the damping force adjustable shock absorber 1 generate a damping force, and this damping force can limit the shaking of the structure.

Also, when an earthquake occurs, power outages may occur. The operation of the damping force adjustable shock absorber 1 when there is no power supply due to a power failure will also be described.

First, in an energized state where the power source is live, when the structure vibrates due to an earthquake, the piston rod 4 is displaced so as to extend and contract from the cylinder 2 . At this time, as shown in FIG. 4, in the damping force generating mechanism 9, the coil 10E of the rod-side actuator 10 is excited to move the plunger 10C having the magnet 10D against the spring 10F. It is placed in a position to squeeze the On the other hand, the bottom-side actuator 11 is arranged at the fully open position where the flow path 8 is opened by moving the plunger 11C having the magnet 11D against the spring 11F by energizing the coil 11E.

Therefore, when the piston rod 4 is contracted, the flow of hydraulic oil from the other side chamber B through the flow path 8 to the reservoir chamber C is restricted by the plunger 10C of the rod side actuator 10. As shown in FIG. Further, when the contraction speed of the piston rod 4 is fast and the pressure in the other side chamber B reaches a predetermined value higher than the pressure in the reservoir chamber C, the first relief valve 15 opens, and the other side chamber B flows into the first relief passage. Hydraulic oil flows into the reservoir chamber C through 13 . The damping force characteristic at this time is as indicated by the solid line in FIG.

When the piston rod 4 is extended, the flow of hydraulic fluid from the reservoir chamber C to the other side chamber B through the flow path 8 is restricted by the plunger 10C of the rod-side actuator 10 . Further, when the extension speed of the piston rod 4 is fast and the pressure in the reservoir chamber C reaches a predetermined value higher than the pressure in the other side chamber B, the second relief valve 16 opens, and the reservoir chamber C flows from the second relief passage. Hydraulic oil flows to the other side chamber B through 14 . The damping force characteristic at this time is as shown by the solid line in FIG.

Next, the operation of the damping force adjustable shock absorber 1 when power supply to the damping force generating mechanism 9 is cut off due to an earthquake, ie, when no power is supplied, will be described.

As shown in FIG. 5, in the damping force generating mechanism 9 when power is not supplied, power supply to the coil 10E of the rod-side actuator 10 is cut off, so the plunger 10C is placed at the fully open position where the flow path 8 is opened by the spring 10F. be done. Further, when power is not supplied, the power supply to the coil 11E of the bottom side actuator 11 is cut off, so the plunger 11C is arranged at the fully closed position where the flow path 8 is cut off by the spring 11F.

Accordingly, when the piston rod 4 is retracted, the flow of hydraulic oil from the other side chamber B to the reservoir chamber C through the passage 8 is restricted by the throttle passage 11H provided in the plunger 11C of the bottom side actuator 11. Further, when the contraction speed of the piston rod 4 is fast and the pressure in the other side chamber B reaches a predetermined value higher than the pressure in the reservoir chamber C, the first relief valve 15 opens, and the other side chamber B flows into the first relief passage. Hydraulic oil flows into the reservoir chamber C through 13 . The damping force characteristic at this time is as indicated by the dotted line in FIG.

When the piston rod 4 is extended with no power supply, the flow of hydraulic oil from the reservoir chamber C to the other side chamber B through the flow path 8 is restricted by the throttle passage 11H provided in the plunger 11C of the bottom side actuator 11. Further, when the extension speed of the piston rod 4 is fast and the pressure in the reservoir chamber C becomes a predetermined value higher than the pressure in the other side chamber B, the plunger 11C opens against the spring 11F, and the flow path from the other side chamber B Hydraulic oil flows into the reservoir chamber C through 8 . Further, when the contraction speed of the piston rod 4 further increases and reaches a predetermined value higher than the valve opening pressure of the plunger 11C, the second relief valve 16 opens, and the flow path 8 and the second relief flow flow from the reservoir chamber C Hydraulic oil flows to the other side chamber B through the passage 14 . The damping force characteristic at this time is as shown by the dotted line in FIG.

As described above, in the first embodiment, the cylinder 2 is provided with the flow path 8 for the hydraulic oil to flow between the other side chamber B and the reservoir chamber C outside the cylinder 2. The flow path 8 includes: A damping force generating mechanism 9 is provided to generate a damping force by regulating the flow of hydraulic oil caused by the movement of the piston 3 by the operation of the rod side actuator 10 and the bottom side actuator 11 .

Therefore, in the first embodiment, the cylinder 2 can be formed as a monotube. As a result, the cylinder 2 can be enlarged, and the damping force adjustable shock absorber 1 can be installed even in a small installation space. Further, by forming the cylinder 2 as a single cylinder, the number of parts can be reduced, and the assembling workability can be improved. Moreover, since the rod-side actuator 10 and the bottom-side actuator 11 can be provided outside the cylinder 2, their mounting work, adjustment work, etc. can be easily performed.

The body portion 6 is provided with a first relief channel 13 as another channel that communicates the other side chamber B with the reservoir chamber C. A first relief valve 15 is provided which opens when the pressure in the chamber C reaches a predetermined value higher than the pressure. On top of this, the actuators are provided on the other side chamber B side and act as a first actuator that operates to circulate hydraulic oil when power is off, and a rod side actuator 10 is provided on the reservoir chamber C side and operates to flow hydraulic oil when power is off. and a bottom side actuator 11 as a second actuator that operates to suppress the flow of water and opens when the pressure in the other side chamber B reaches a predetermined value lower than the pressure in the reservoir chamber C.

As a result, even when the power supply to the damping force generating mechanism 9 is cut off due to an earthquake and the power supply is turned off, the same damping force as in the normal power supply state can be obtained, and the damping force adjustable shock absorber 1 can control vibration. performance can be maintained.

7 and 8 show a second embodiment of the invention. This embodiment is characterized by another flow path provided in the body portion that communicates with the other side chamber and the reservoir chamber, and a predetermined a relief valve that opens when the pressure reaches a value, the actuator is provided on the side of the other side chamber, operates to suppress the flow of the working fluid when no power is supplied, and the pressure of the other side chamber is higher than the pressure of the reservoir chamber. It has a first actuator that opens the valve when a predetermined value is reached, and a second actuator that is provided on the side of the reservoir chamber and operates to allow the working fluid to flow when power is not supplied. In addition, in 2nd Embodiment, the same code|symbol shall be attached|subjected to the component same as 1st Embodiment mentioned above, and the description shall be abbreviate|omitted.

Here, in the second embodiment, the second relief channel 14 provided in the body portion 6 constitutes another channel.

7 and 8, the damping force generating mechanism 21 according to the second embodiment includes a rod-side actuator 22 as a first actuator and a bottom-side actuator 23 as a second actuator.

The rod-side actuator 22 is provided on the side of the other side chamber B, operates to suppress the flow of hydraulic oil when power is off, and opens when the pressure in the other side chamber B reaches a predetermined value higher than the pressure in the reservoir chamber C. . The rod-side actuator 22 includes a cylindrical portion 22A, a shaft hole 22B, a plunger 22C, a magnet 22D, a coil 22E, a spring 22F, and a connection hole 22G, similarly to the rod-side actuator 10 according to the first embodiment. .

However, in the rod-side actuator 22 according to the second embodiment, the throttle passage 22H is provided through the plunger 22C in the axial direction, and the spring 22F biases the plunger 22C in the valve closing direction. It is different from the rod-side actuator 10 according to the first embodiment in that it is arranged at . The configuration of this rod-side actuator 22 is the same as the configuration of the bottom-side actuator 11 according to the first embodiment.

The bottom side actuator 23 is provided on the side of the reservoir chamber C, and operates so that hydraulic oil is circulated when power is not supplied. The bottom-side actuator 23 includes a tubular portion 23A, a shaft hole 23B, a plunger 23C, a magnet 23D, a coil 23E, a spring 23F, and a connection hole 23G, like the bottom-side actuator 11 according to the first embodiment. .

However, the bottom-side actuator 23 according to the second embodiment is second in that the throttle passage is eliminated and the spring 23F is arranged at a position that biases the plunger 23C in the valve opening direction. It is different from the bottom side actuator 11 according to the first embodiment. The configuration of the bottom side actuator 23 is the same as the configuration of the rod side actuator 10 according to the first embodiment.

Here, the rod-side actuator 22 and the bottom-side actuator 23 operate in the same manner as the bottom-side actuator 11 according to the first embodiment, and the bottom-side actuator 23 operates like the rod-side actuator 23 according to the first embodiment. Since the operation is the same as that of the actuator 10, it will be omitted.

Thus, substantially the same effects as those of the first embodiment described above can be obtained in the second embodiment configured as described above.

In each embodiment, the case where the damping force adjustable shock absorber 1 is used to suppress the vibration acting on the building has been described as an example. However, the present invention is not limited to this. It can also be applied to various damping force adjustable shock absorbers that dampen the vibration of the object to be damped.

As a damping force adjustable shock absorber based on the embodiment described above, for example, the following modes are conceivable.

A first aspect of the damping force adjustable shock absorber includes a cylinder in which a working fluid is sealed, a piston inserted into the cylinder to define the inside of the cylinder into one side chamber and the other side chamber, and the piston a piston rod that is connected and extends to the outside of the cylinder; and a body portion that is inserted into the other side chamber in the cylinder and is provided so as to divide the inside of the cylinder into the other side chamber and a reservoir chamber for ensuring volume. a flow path through which the working fluid flows between the other side chamber and the reservoir chamber; and an actuator provided in the flow path regulates the flow of the working fluid generated by the movement of the piston to reduce the damping force. and a damping force generating mechanism for generating the damping force.

As a second aspect, in the first aspect, there is another flow path provided in the body portion for communicating the other side chamber and the reservoir chamber, and a a relief valve that opens when the pressure reaches a predetermined value higher than the pressure in the reservoir chamber, and the actuator is provided on the side of the other side chamber and operates to allow the working fluid to flow when power is not supplied. A first actuator is provided on the reservoir chamber side, operates to suppress the flow of the working fluid when power is off, and opens when the pressure in the other side chamber reaches a predetermined value lower than the pressure in the reservoir chamber. and a second actuator.

As a third aspect, in the first aspect, another flow path provided in the body portion for communicating the other side chamber and the reservoir chamber; a relief valve that opens when the pressure reaches a predetermined value higher than the pressure in the other side chamber, and the actuator is provided on the side of the other side chamber to suppress the flow of the working fluid when power is off. a first actuator that operates and opens when the pressure in the other side chamber reaches a predetermined value higher than the pressure in the reservoir chamber; and a second actuator.

1: damping force adjustable shock absorber, 2: cylinder, 3: piston, 4: piston rod, 6: body portion, 8: flow path, 9, 21: damping force generating mechanism, 10, 22: rod side actuator (second 1 actuator), 11, 23: bottom side actuator (second actuator), 13: first relief channel (another channel), 14: second relief channel (another channel), 15: first relief valve (relief valve), 16: second relief valve (relief valve), A: one side chamber, B: other side chamber, C: reservoir chamber

Claims (3)

a cylinder in which the working fluid is sealed;
a piston that is inserted into the cylinder and defines the inside of the cylinder into one side chamber and the other side chamber;
a piston rod connected to the piston and extending to the outside of the cylinder;
a body portion that is inserted into the other side chamber in the cylinder and is provided so as to partition the inside of the cylinder into the other side chamber and a reservoir chamber that ensures volume;
a channel through which the working fluid flows between the other side chamber and the reservoir chamber;
a damping force generating mechanism that regulates the flow of the working fluid generated by the movement of the piston by the operation of an actuator provided in the flow path to generate a damping force;
damping force adjustable shock absorber. A shock absorber according to claim 1,
another flow path provided in the body portion and communicating between the other side chamber and the reservoir chamber;
a relief valve provided in the other flow path and opened when the pressure in the other side chamber reaches a predetermined value higher than the pressure in the reservoir chamber;
has
The actuator is
a first actuator provided on the side of the other side chamber and operated to allow the working fluid to flow when no power is supplied;
a second actuator provided on the reservoir chamber side, operating to suppress the flow of the working fluid when no power is supplied, and opening the valve when the pressure in the other side chamber reaches a predetermined value lower than the pressure in the reservoir chamber;
damping force adjustable shock absorber. A shock absorber according to claim 1,
another flow path provided in the body portion and communicating between the other side chamber and the reservoir chamber;
a relief valve provided in the other flow path and opened when the pressure in the reservoir chamber reaches a predetermined value higher than the pressure in the other side chamber;
has
The actuator is
a first actuator provided on the side of the other side chamber, operating to suppress the flow of the working fluid when power is off, and opening the valve when the pressure in the other side chamber reaches a predetermined value higher than the pressure in the reservoir chamber;
a second actuator provided on the reservoir chamber side and operated to allow the working fluid to flow when power is off;
damping force adjustable shock absorber.

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