JP5728318B2 - Variable damping force damper - Google Patents

Description

  The present invention relates to a damping force variable damper that is used in a vehicle suspension device and can change a damping force by sliding a piston in a cylinder.

Among the damping force variable dampers, there are known ones in which a cylinder is divided into first and second fluid chambers by a piston slidably accommodated in the cylinder, and a piezoelectric body and a spool are accommodated in the piston.
According to this damping force variable damper, the spool is moved by applying a voltage to the piezoelectric body to expand and contract the piezoelectric body.
By moving the spool, the damping force can be adjusted by changing the opening area of the communication hole (side hole formed in the peripheral wall of the piston) (for example, see Patent Document 1).

JP 61-85210 A

Here, the expansion / contraction amount (displacement amount) of the piezoelectric body is very small, and the movement amount of the spool is also small.
In order to adjust the opening area of the communication hole (side hole formed in the peripheral wall of the piston) by moving the spool to a small amount, it is necessary to adjust the amount of movement of the spool with high accuracy.
However, in order to adjust the movement amount of the spool with high accuracy, it is necessary to accurately control the voltage applied to the piezoelectric body, and the control for applying the voltage to the piezoelectric body is complicated.

  It is an object of the present invention to provide a damping force variable damper that can change the damping force by simple control.

According to a first aspect of the present invention, there is provided a damping force variable damper that is used in a vehicle suspension device and is capable of changing a damping force, and a cylinder filled with fluid, and a cylinder that is slidably accommodated in the cylinder. Is divided into first and second fluid chambers, and a piston having a fluid passage for communicating the first and second fluid chambers, and a piston provided in the piston and pressed toward the fluid passage, thereby A valve means capable of closing the fluid passage and capable of opening the fluid passage when the piston slides; and a state of being connected to the valve means and partitioned from one of the first and second fluid chambers And a piezoelectric body capable of changing a force for pressing the valve means toward the fluid passage in accordance with an applied voltage, and one of the first and second fluid chambers. Low hydraulic pressure When the piston slides, the valve means can be separated from the fluid passage and the fluid passage can be opened by the pressure difference between the fluid in the first fluid chamber and the fluid in the second fluid chamber. When the piston slides so that the hydraulic pressure of one of the first and second fluid chambers is increased, the valve means is moved away from the fluid passage with the increased hydraulic pressure. A cylindrical piston case that can open a fluid passage and slides in the cylinder of the piston has a piston space inside, and a piezoelectric body connected to the valve means is a piezoelectric body provided in the piston space. The piezoelectric material storage chamber is a space that is provided between the piston case and the valve means and is surrounded by a metal bellows, and is partitioned in a sealed state with respect to the piston space. And is characterized in that the interior is held in a lower pressure than the hydraulic fluid of the first fluid chamber by being held at atmospheric pressure.

  According to a second aspect of the present invention, the valve means includes a valve support member provided on the piezoelectric body side, a valve member movably supported by the valve support member, and capable of opening and closing the fluid passage, and the valve member as the fluid. And a valve urging means capable of closing the fluid passage with the valve member by pressing toward the passage, and the valve support member moves the valve member by the urging force of the valve urging means. It has the control part which controls.

  According to a third aspect of the present invention, the valve means is provided on the piezoelectric body side and is displaceable in an expansion / contraction direction corresponding to expansion / contraction of the piezoelectric body, and displacement of the valve support member is orthogonal to the displacement direction A displacement transmitting means capable of transmitting in a direction to be moved, a valve member supported movably by the displacement transmitting means, and capable of opening and closing the fluid passage; and pressing the valve member toward the fluid passage, thereby Valve urging means capable of closing the fluid passage with a member.

According to the first aspect of the present invention, the fluid passage is closed by pressing the valve means toward the fluid passage with the piezoelectric body, and the fluid passage can be opened by the valve means when the piston slides.
Then, the voltage (pressing force) for pressing the valve means is changed by controlling the voltage applied to the piezoelectric body.
By changing the pressing force that presses the valve means, it is possible to change the opening area of the fluid passage (that is, the flow path cross-sectional area) corresponding to the pressing force during the sliding of the piston.
The damping force of the damping force variable damper can be changed by changing the cross-sectional area of the fluid passage during the sliding of the piston.

Thus, according to the first aspect of the invention, the damping force can be changed by changing the pressing force applied to the valve means by the piezoelectric body.
Therefore, as described in the prior art, it is not necessary to adjust the opening area of the fluid passage by changing the damping force by applying a voltage to the piezoelectric body to expand and contract the piezoelectric body.
For this reason, it is not necessary to adjust the amount of movement of the valve means by the piezoelectric body with higher precision than necessary.
Since high-precision adjustment of the valve means can be eliminated, it is not necessary to accurately control the voltage applied to the piezoelectric body when moving the valve means.

As a result, the voltage applied to the piezoelectric body can be easily controlled, and the damping force of the damping force variable damper can be changed by simple control.
In particular, as an example, the relationship between the voltage applied to the piezoelectric body and the damping force obtained according to the voltage is mapped, and the adjustment of the damping force can be controlled more easily by using this characteristic map. is there.

Furthermore, in the invention according to claim 1, the piezoelectric body is provided in a state of being partitioned from one of the first and second fluid chambers.
The reason for partitioning the piezoelectric body from one of the first and second fluid chambers is as follows.
That is, as the damping force variable damper, for example, a monotube (single cylinder type) damper in which a gas chamber (an air chamber instead of the gas chamber) is provided adjacent to the other of the first and second fluid chambers is used. Sometimes.
The monotube damper is a commonly used damper.

In the monotube damper, the other fluid chamber and the gas chamber are partitioned by a free piston.
By separating the other fluid chamber from the gas chamber by a free piston, the free piston slides together with the piston when the damping force variable damper expands and contracts.
Thus, when the damping force variable damper expands and contracts, the free piston slides, so that the pressure fluctuation in the other fluid chamber adjacent to the gas chamber is kept substantially constant.

Therefore, a difference occurs in the pressure fluctuation between the fluid in the first fluid chamber and the second fluid chamber.
Here, the piston slides in a direction in which the fluid pressure in one fluid chamber increases and a direction in which the fluid pressure decreases relative to the fluid pressure in the other fluid chamber in which the pressure fluctuation is maintained substantially constant.

  For this reason, the pressure difference is utilized in both the case where the fluid pressure in one fluid chamber is high and the case where the fluid pressure is low compared to the other fluid chamber in which the pressure fluctuation is kept substantially constant. It is necessary to separate the valve urging means from the fluid passage and to reliably open the fluid passage by changing the force from a single direction.

Therefore, in claim 1, the piezoelectric body is provided in a state of being partitioned from one of the first and second fluid chambers. By partitioning the piezoelectric body from one of the first and second fluid chambers, a portion of the valve means connected to the piezoelectric body can be partitioned from one of the first and second fluid chambers.
Therefore, one hydraulic pressure of the first and second fluid chambers can be prevented from acting on a portion of the valve means connected to the piezoelectric body.
As a result, when the piston slides so that the hydraulic pressure of one of the first and second fluid chambers is increased, the valve means is moved away from the fluid path with the increased hydraulic pressure to It can be opened reliably.

On the other hand, when the piston slides so that the hydraulic pressure of one of the first and second fluid chambers becomes low, the valve means is fluidized by the pressure difference between the fluid in the first fluid chamber and the fluid in the second fluid chamber. The fluid passage can be opened away from the passage.
Further, in claim 1, the cylindrical piston case that slides in the piston cylinder has a piston space inside, and the piezoelectric body connected to the valve means is housed in a piezoelectric body housing chamber provided in the piston space. The body storage chamber is provided between the piston case and the valve means, and is a space surrounded by a metal bellows, and is hermetically partitioned with respect to the piston space, and the interior is maintained at atmospheric pressure. Thus, the hydraulic fluid in the first fluid chamber is held at a lower pressure.

In the invention according to claim 2, the valve support member has the restricting portion, and the restricting portion restricts the movement of the valve member.
Therefore, when the piezoelectric body is contracted (compressed) to move the valve support member away from the fluid passage, the valve member can be reliably moved by the restricting portion of the valve support member.
Thus, the fluid passage can be satisfactorily opened by reliably moving the valve member at the restricting portion.
Furthermore, since the movement of the valve member can be restricted simply by providing the valve support member with the restricting portion, the configuration can be simplified.

According to the third aspect of the present invention, the displacement transmitting means is provided, and the displacement transmitting means can transmit the displacement of the valve support member in a direction orthogonal to the displacement direction.
The displacement direction of the valve support member is the same as the expansion / contraction direction of the piezoelectric body. Therefore, by providing the displacement transmitting means, the valve member can be provided in a direction orthogonal to the expansion / contraction direction of the piezoelectric body.

Thus, by providing the valve member in a direction orthogonal to the expansion / contraction direction of the piezoelectric body, the amount of protrusion of the valve member in the axial direction relative to the piezoelectric body can be suppressed to a small value.
Thereby, since the length dimension to the axial direction of a piston can be restrained small, size reduction of a piston can be achieved and the freedom degree of design can be raised.

It is sectional drawing which shows the damping-force variable damper of Example 1 which concerns on this invention. It is sectional drawing which shows the piston assembly of the damping-force variable damper of FIG. It is sectional drawing which shows the bellows of FIG. 2 in a cross section. It is sectional drawing which shows the valve | bulb means of FIG. It is a figure explaining the example which applies a voltage to the piezoelectric material of Example 1, and closes a fluid passage with a valve means. It is a figure which shows the state which contracts (compresses) the damping-force variable damper of Example 1. FIG. It is a figure explaining the example which slides a piston assembly downward and obtains damping force. It is a figure which shows the state which expand | extends the damping-force variable damper of Example 1. FIG. It is a figure explaining the example which slides a piston assembly upward and obtains damping force. It is sectional drawing which shows the damping-force variable damper of Example 2 which concerns on this invention. (A) is the 11a part enlarged view of FIG. 10, (b) is sectional drawing which shows the state which pushed down the press rod of (a). 12 is a sectional view taken along line 12-12 of FIG. It is a figure explaining the example which applies a voltage to the piezoelectric material of Example 2, and obstructs an upper and lower fluid passage with valve means. It is a figure explaining the example which slides a piston assembly downward and obtains damping force, when the damping force variable damper of Example 2 is contracted (compressed). It is a figure explaining the example which obtains damping force by sliding a piston assembly upward when extending the damping force variable damper of Example 2. FIG.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

The damping force variable damper 10 according to the first embodiment will be described.
As shown in FIG. 1, the damping force variable damper 10 is a shock absorber that is used in the suspension device of the vehicle 11 and can change the damping force.

  The damping force variable damper 10 includes a cylindrical cylinder (cylinder tube) 12, a piston assembly 14 slidably accommodated in the cylinder 12, and an upper end portion 12 a of the cylinder 12 connected to the piston assembly 14. And a free piston 17 slidably housed below the piston assembly 14.

  Further, in the damping force variable damper 10, the piezoelectric body 56 of the piston assembly 14 is connected to the control unit 22 through the wire harness 21, the piezoelectric body 56 is connected to the power source (battery) 24, and the power source 24 is the electrical component 25. It is connected to the.

The cylinder 12 is filled with hydraulic oil (fluid) 13, the piston assembly 14 is slidably accommodated in the arrow direction, and the free piston 17 is slidably accommodated in the arrow direction.
Therefore, the inside of the cylinder 12 is divided into an upper fluid chamber (first fluid chamber) 31, a lower fluid chamber (second fluid chamber) 32, and a gas chamber (air chamber) 33 by the piston assembly 14 and the free piston 17.

Specifically, in the damping force variable damper 10, a piston assembly 14 is accommodated in the approximate center of the cylinder 12, and a free piston 17 is accommodated below the piston assembly 14.
By accommodating the piston assembly 14 in the cylinder 12, the inside of the cylinder 12 is partitioned into an upper fluid chamber 31 and a lower fluid chamber 32 by the piston assembly 14.
The upper fluid chamber 31 and the lower fluid chamber 32 are filled with hydraulic oil 13.

Further, the free piston 17 is housed in the cylinder 12 below the piston assembly 14, so that the gas chamber 33 is partitioned adjacent to the lower fluid chamber 32.
The gas chamber 33 is filled with the high-pressure gas 18.
That is, the damping force variable damper 10 is a monotube (single cylinder type) damper in which the gas chamber 33 is provided adjacent to the lower fluid chamber 32.
The monotube damper is a shock absorber generally used as a suspension device for the vehicle 11.

According to the damping force variable damper 10, the piston assembly 14 and the free piston 17 can be slid in the direction of the arrow within the cylinder 12 when the damping force variable damper 10 expands and contracts.
The hydraulic oil 13 can be moved between the upper fluid chamber 31 and the lower fluid chamber 32 by sliding the piston assembly 14 in the arrow direction.
By moving the hydraulic oil 13 between the upper fluid chamber 31 and the lower fluid chamber 32, the damping force can be obtained by the damping force variable damper 10.

  As shown in FIG. 2, the piston assembly 14 includes a piston case (piston) 35 slidably accommodated in the cylinder 12, a bellows (partition member) 51 provided in the piston case 35, and an inside of the bellows 51. And a valve means 62 connected to the piezoelectric body 56 side.

The piston case 35 is a case that can be accommodated in the cylinder 12 and slidable in the axial direction (vertical direction) of the cylinder 12.
The piston case 35 has a piston space 67 by being formed in a cylindrical shape. The bellows 51 and the valve means 62 are accommodated in the piston space 67.

Specifically, in the piston case 35, an upper portion 35a is integrally connected to the lower end portion 16a of the piston rod 16, a piston ring 38 is provided at the lower portion 35b, and a piston bottom portion 75 is provided below the piston ring 38. .
A piezoelectric body 56 is fitted into a rod locking hole 35c formed in the upper portion 35a of the piston case 35.

The piston case 35 is formed in a cylindrical shape, and a plurality of piston openings 37 are provided in the circumferential direction of the peripheral wall 36.
By providing the piston opening 37 in the peripheral wall 36, the piston space 67 in the piston case 35 is communicated with the upper fluid chamber 31 through the piston opening 37.

The piston bottom 75 is provided below the piston opening 37, and a fluid passage 78 is provided in the center.
By providing the fluid passage 78 in the center of the piston bottom 75, the piston space 67 in the piston case 35 is communicated with the lower fluid chamber 32 via the fluid passage 78.
Therefore, the lower fluid chamber 32 communicates with the upper fluid chamber 31 via the fluid passage 78, the piston space 67 and the piston opening 37.

The piston ring 38 is formed in an annular shape, and an outer peripheral surface 38 a is slidably in contact with the inner peripheral surface 12 b of the cylinder 12.
The piston assembly 14 is slidably supported in the axial direction (arrow direction) of the cylinder 12 by the outer peripheral surface 38 a of the piston ring 38 being slidably contacted with the inner peripheral surface 12 b of the cylinder 12.

Further, the piston ring 38 is slidably contacted with the inner peripheral surface 12b of the cylinder 12 so that the space between the outer peripheral surface 38a and the inner peripheral surface 12b is sealed.
Therefore, the inside of the cylinder 12 is partitioned into the upper fluid chamber 31 and the lower fluid chamber 32 by the piston ring 38.

As shown in FIG. 3, the bellows 51 is a metal partition member formed of a steel material in a cylindrical shape as an example.
By forming the bellows 51 from a steel material, the rigidity of the bellows 51 can be secured.
The reason for ensuring the rigidity of the bellows 51 will be described in detail later.

  The bellows 51 includes a bellows body 52 having a cylindrical peripheral wall formed in a bellows shape, an annular upper mounting portion 53 provided at the upper end portion of the bellows body 52, and an annular shape provided at the lower end portion of the bellows body 52. And a lower mounting portion 54.

The annular upper mounting portion 53 is integrally connected to the bellows support portion 35d of the piston case 35 (upper portion 35a).
A piezoelectric body 56 is passed through the rod locking hole 35c of the piston case 35 (upper part 35a).
A lower portion 56a of the piezoelectric body 56 protrudes downward through the rod locking hole 35c. A lower portion 56 a protruding downward from the rod locking hole 35 c is covered with a bellows body 52.

The bellows body 52 is formed to be extendable and contractable in the axial direction by forming a cylindrical peripheral wall in a bellows shape.
Therefore, the bellows main body 52 can be expanded and contracted corresponding to the expansion and contraction of the piezoelectric body 56.

The annular lower mounting portion 54 is welded (joined) in a state of being fitted into the outer peripheral wall of the valve support member 63 (specifically, the piezoelectric / bellows connecting portion 91) of the valve means 62.
In this state, the lower gap 88 between the lower mounting portion 54 and the piezoelectric / bellows connecting portion 91 is sealed.

  In this way, the upper mounting portion 53 is integrally connected to the bellows support portion 35d of the upper portion 35a, and the lower gap 88 between the lower mounting portion 54 and the piezoelectric / bellows connecting portion 91 is sealed, so that the piezoelectric in the bellows 51 is sealed. The body storage chamber 66 is partitioned from the piston space 67.

That is, the piezoelectric body storage chamber 66 is a space in which the lower part 56 a of the piezoelectric body 56 can be stored in a state of being partitioned from the piston space 67.
The piezoelectric body chamber 66 communicates with the external space of the damping force variable damper 10 and is partitioned from the piston space 67 in a sealed state.

Therefore, the bellows 51 can prevent the hydraulic oil 13 filled in the piston space 67 from entering the piezoelectric body storage chamber 66. Thereby, the piezoelectric body 56 can be protected from the hydraulic oil 13 by the bellows 51.
Furthermore, the piezoelectric body storage chamber 66 is maintained at atmospheric pressure by communicating with the external space.

Here, as described above, the bellows 51 is formed of a steel material to ensure rigidity.
Therefore, it is possible to prevent the bellows 51 from being deformed by a pressure difference between the hydraulic pressure (hydraulic pressure) of the hydraulic oil 13 acting on the outer peripheral wall of the bellows 51 and the atmospheric pressure acting on the inner peripheral wall of the piezoelectric body storage chamber 66.

The bellows 51 covers the lower portion 56a of the piezoelectric body 56 and the upper surface of the piezoelectric / bellows connecting portion 91 (the portion of the valve means 62 connected to the piezoelectric body 56) 91a.
Therefore, the lower portion 56a of the piezoelectric body 56 and the upper surface 91a of the piezoelectric / bellows connecting portion 91 are partitioned from the piston space 67 (that is, the upper and lower fluid chambers 31, 32).
Thereby, the hydraulic pressure of the hydraulic oil 13 filled in the piston space 67 (that is, the hydraulic oil 13 in the upper and lower fluid chambers 31, 32) acts on the lower portion 56 a of the piezoelectric body 56 and the upper surface 91 a of the piezoelectric / bellows connecting portion 91. Can be prevented.

Here, the internal pressure of the piezoelectric body storage chamber 66 is maintained at atmospheric pressure, and is kept lower than the operating hydraulic pressure (hydraulic pressure) of the upper fluid chamber 31.
As described above, the pressure acting on the upper surface 91a of the piezoelectric / bellows connecting portion 91 is kept low by keeping the internal pressure of the piezoelectric body storage chamber 66 low.
The reason why the pressure acting on the upper surface 91a of the piezoelectric / bellows connecting portion 91 is kept low will be described in detail later.

The piezoelectric body 56 has a plurality of piezoelectric elements (piezo elements) single bodies 57 stacked in the vertical direction.
The piezoelectric body 56 can be extended by applying a voltage from the power source 24 (see FIG. 1) to the plurality of single piezoelectric elements 57.

The upper portion 56 b of the piezoelectric body 56 is accommodated (provided) coaxially in the lower end portion 16 a of the piston rod 16, and the lower portion 56 a is accommodated in the piezoelectric body accommodating chamber 66 in the bellows 51.
In this state, the lower end portion 56 d of the piezoelectric body 56 is connected (contacted) to the piezoelectric / bellows connecting portion 91 of the valve means 62.

An upper end portion 56c of the piezoelectric body 56 is connected to the control unit 22 and the power source 24 (see FIG. 1) via the wire harness 21.
The control unit 22 illustrated in FIG. 1 has a function of switching a state in which a voltage is applied from the power source 24 to the piezoelectric body 56 and a state in which the voltage is not applied from the power source 24.
Furthermore, the control unit 22 has a function of adjusting (changing) the voltage applied from the power source 24 to the piezoelectric body 56.

When a voltage is applied from the power supply 24 to the piezoelectric body 56, the piezoelectric body 56 expands.
By extending the piezoelectric body 56, the valve means 62 can be pressed toward the piston bottom 75 of the piston case 35 by the piezoelectric body 56.

The valve means 62 is provided on the piston case 35 (piston rod 16) via the piezoelectric body 56.
The valve means 62 includes a valve support member 63 provided on the piezoelectric body 56 side, a valve member 64 movably supported by the valve support member 63, and a valve capable of pressing the valve member 64 toward the fluid passage 78. An urging spring (valve urging means) 65 is provided.

  As shown in FIG. 4, the valve support member 63 includes a piezoelectric / bellows connecting portion 91 connected to the piezoelectric body 56 side, a valve guide portion 96 provided coaxially with the piezoelectric / bellows connecting portion 91, and a valve guide. And a valve restricting portion (regulating portion) 101 provided in the portion 96.

The piezoelectric / bellows connecting portion 91 has a second pressure receiving portion 91b formed on the lower surface.
The second pressure receiving portion 91b is a portion that causes the pressure of the hydraulic oil 13 in the upper fluid chamber 31 to act upward.
By causing the pressure of the hydraulic oil 13 in the upper fluid chamber 31 to act upward on the second pressure receiving portion 91b, a load for contracting (compressing) the piezoelectric body 56 can be applied.

The valve guide portion 96 has a cylindrical portion 97 that protrudes coaxially downward from the piezoelectric / bellows connecting portion 91.
A valve sliding portion 105 of the valve member 64 is accommodated (supported) in an internal space 98 of the cylindrical portion 97 so as to be movable in the vertical direction.
A valve restricting portion 101 is provided at the lower end 97 a of the cylindrical portion 97.

The valve restricting portion 101 is provided at the lower end 97a of the cylindrical portion 97, and an opening 102 is formed at the center. A valve support shaft 106 passes through the opening 102.
An inner peripheral edge 101 a of the opening portion 102 of the valve restricting portion 101 projects toward the center of the cylindrical portion 97.

By causing the outer peripheral edge 105a of the valve sliding portion 105 to contact the inner peripheral edge 101a, the movement of the valve sliding portion 105 (that is, the valve member 64) due to the biasing force (spring force) of the valve biasing spring 65 is regulated. be able to.
That is, the valve restricting portion 101 is a member that restricts the movement of the valve member 64 due to the urging force of the valve urging spring 65.

  The valve member 64 includes a valve sliding portion 105 housed in an internal space 98 of the cylindrical portion 97 so as to be movable in the vertical direction, a valve support shaft 106 protruding downward from the valve sliding portion 105, and a valve support. And a valve main body 107 provided at the lower end of the shaft 106.

The valve sliding portion 105 is formed in a disk shape and is housed in an internal space 98 of the cylindrical portion 97 so as to be movable in the vertical direction.
The valve member 64 can be held at the restricting position P1 by bringing the outer peripheral edge 105a of the valve sliding portion 105 into contact with the inner peripheral edge 101a of the valve restricting portion 101 from above.

The valve support shaft 106 protrudes downward from the valve sliding portion 105 and is slidably penetrated through the opening 102 of the valve restricting portion 101.
Providing the valve support shaft 106 in the valve sliding portion 105 allows the valve sliding portion 105 to move in the vertical direction.

The valve body 107 is provided at the lower end portion of the valve support shaft 106 and is formed in a disk shape having substantially the same diameter as the outer diameter of the cylindrical portion 97.
The valve body 107 can close the fluid passage 78 when pressed against the surface 75a of the piston bottom 75, and can open the fluid passage 78 when separated from the surface 75a of the piston bottom 75. Is formed.
A first pressure receiving portion 107 a facing the fluid passage 78 is provided at the center of the valve body 107.
A pressure difference (that is, a differential pressure) between the hydraulic oil 13 in the upper fluid chamber 31 (see FIG. 3) and the hydraulic oil 13 in the lower fluid chamber 32 acts on the first pressure receiving portion 107a.

The valve urging spring 65 is a compression spring that is accommodated in the internal space 98 of the cylindrical portion 97 and is disposed in a compressed state between the upper end portion 96 a of the cylindrical portion 97 and the valve sliding portion 105.
The valve member 64 (valve sliding portion 105) is pressed toward the fluid passage 78 by the biasing force of the valve biasing spring 65.

By pressing the valve member 64 toward the fluid passage 78, the outer peripheral edge 105 a of the valve sliding portion 105 is kept in contact with the inner peripheral edge 101 a of the valve restricting portion 101.
The valve member 64 is held at the restricting position P1 by maintaining the outer peripheral edge 105a in contact with the inner peripheral edge 101a.

In a state where the valve member 64 is held at the restricting position P1, the valve body 107 is pressed against the surface 75a of the piston bottom 75 by applying a voltage to the piezoelectric body 56 and extending the piezoelectric body 56.
By pressing the valve body 107 against the surface 75 a of the piston bottom 75, the fluid passage 78 is closed by the valve body 107.

On the other hand, when the valve member 64 is pressed toward the fluid passage 78, the outer peripheral edge 105 a of the valve sliding portion 105 is kept in contact with the inner peripheral edge 101 a of the valve restricting portion 101.
That is, the movement of the valve member 64 can be restricted by the valve restriction part 101.

Therefore, by releasing the voltage from the piezoelectric body 56 and contracting the piezoelectric body 56, the valve main body 107 is reliably separated (separated) from the surface 75 a of the piston bottom 75 together with the valve restricting portion 101.
By separating the valve body 107 from the surface 75a of the piston bottom 75, the fluid passage 78 is satisfactorily opened.

As described above, by restricting the movement of the valve member 64 by the valve restricting portion 101, the fluid passage 78 can be satisfactorily closed and opened by the valve main body 107.
The restriction of the valve member 64 can be realized with a simple configuration in which the valve support member 63 includes the valve restriction portion 101.
Thereby, simplification of the structure of the damping force variable damper 10 can be achieved.

Next, an example in which a voltage is applied to the piezoelectric body 56 to close the fluid passage 78 with the valve means 62 will be described with reference to FIG.
As shown in FIG. 5A, the valve member 64 is pressed toward the fluid passage 78 by the valve biasing spring 65.
By pressing the valve member 64, the outer peripheral edge 105 a of the valve sliding portion 105 is kept in contact with the inner peripheral edge 101 a of the valve restricting portion 101.
The valve member 64 is held at the restricting position P1 by maintaining the outer peripheral edge 105a in contact with the inner peripheral edge 101a.

In this state, the control unit 22 is controlled to apply a voltage from the power supply 24 to the piezoelectric body 56 to extend the piezoelectric body 56 as indicated by an arrow A.
As the piezoelectric body 56 extends, the valve support member 63 descends as shown by an arrow B.
When the valve support member 63 is lowered, the valve member 64 is lowered together with the valve support member 63 toward the piston bottom portion 75 as indicated by an arrow C.

As shown in FIG. 5B, the valve member 64 descends toward the piston bottom 75, thereby pressing the valve body 107 of the valve member 64 against the surface 75 a of the piston bottom 75.
Thus, by pressing the valve body 107 against the surface 75 a of the piston bottom 75, the fluid passage 78 can be closed by the valve body 107.

Next, an example in which the damping force is obtained by sliding the piston assembly 14 when the damping force variable damper 10 expands and contracts will be described with reference to FIGS.
First, an example in which the damping force is obtained by sliding the piston assembly 14 downward when the damping force variable damper 10 contracts (compresses) will be described with reference to FIGS.

As shown in FIG. 6A, the damping force variable damper 10 contracts (compresses) when the compression force F <b> 1 acts on the damping force variable damper 10.
As the damping force variable damper 10 contracts, the piston assembly 14 and the free piston 17 slide as shown by an arrow D.

As shown in FIG. 6B, the volume of the upper fluid chamber 31 is increased by sliding the piston assembly 14, and the hydraulic pressure of the hydraulic oil 13 in the upper fluid chamber 31 is decreased.
Further, as the piston assembly 14 and the free piston 17 slide, the volume change of the lower fluid chamber 32 accompanying the sliding of the piston assembly 14 is absorbed by the gas chamber 33.
Therefore, the hydraulic pressure (hydraulic pressure) of the hydraulic oil 13 in the lower fluid chamber 32 is kept almost unchanged.
Thereby, a relatively large pressure difference between the hydraulic oil 13 in the upper fluid chamber 31 and the hydraulic oil 13 in the lower fluid chamber 32 can be secured.

As shown in FIG. 7A, the fluid passage 78 is closed by the valve body 107 in a state where a voltage is applied to the piezoelectric body 56.
In this state, the piston assembly 14 slides downward as indicated by the arrow D by contracting the damping force variable damper 10.

By sliding the piston assembly 14 downward, the volume of the upper fluid chamber 31 increases, and the hydraulic pressure of the hydraulic oil 13 in the upper fluid chamber 31 decreases.
Therefore, it is possible to ensure a relatively large pressure difference between the hydraulic oil 13 in the upper fluid chamber 31 and the hydraulic oil 13 in the lower fluid chamber 32 (that is, the differential pressure Po1).

A pressing force Fo1 acts on the first pressure receiving portion 107a of the valve main body 107 by the differential pressure Po1 secured relatively large.
When the pressing force Fo1 acting on the first pressure receiving portion 107a exceeds the balance load Fb1, the valve urging spring 65 of the valve means 62 is compressed.
Here, the balance load Fb <b> 1 is a load that acts due to the compression state of the valve urging spring 65 (that is, a force that presses the valve main body 107 with the valve urging spring 65).

As shown in FIG. 7B, when the valve urging spring 65 is compressed, the valve body 107 is pushed up in the direction of separating (separating) from the fluid passage 78 as shown by an arrow E, and the fluid passage 78 is opened. .
When the fluid passage 78 is opened, the hydraulic oil 13 in the lower fluid chamber 32 is guided to the piston space 67 through the fluid passage 78 as indicated by an arrow F.
The hydraulic oil 13 guided to the piston space 67 is guided to the outside of the piston case 35 (that is, the upper fluid chamber 31) through the piston opening 37 as indicated by an arrow G.

Thereby, when the damping force variable damper 10 contracts and the piston assembly 14 slides downward, the hydraulic oil 13 in the lower fluid chamber 32 can be smoothly guided to the upper fluid chamber 31 via the fluid passage 78. .
Thus, by smoothly flowing the hydraulic oil 13 through the fluid passage 78, a damper damping force determined by the pressing force Fo1 (see FIG. 7A) is obtained.

  Next, an example in which the damping force is obtained by sliding the piston assembly 14 upward when the damping force variable damper 10 extends will be described with reference to FIGS.

As shown in FIG. 8A, the damping force variable damper 10 is extended by the tensile force F <b> 2 acting on the damping force variable damper 10.
As the damping force variable damper 10 extends, the piston assembly 14 and the free piston 17 slide as shown by an arrow H.

As shown in FIG. 8B, the volume of the upper fluid chamber 31 is reduced by the sliding of the piston assembly 14, and the hydraulic pressure of the hydraulic fluid 13 in the upper fluid chamber 31 is increased.
On the other hand, as the piston assembly 14 and the free piston 17 slide, the volume change of the lower fluid chamber 32 accompanying the sliding of the piston assembly 14 is absorbed by the gas chamber 33.
Therefore, the hydraulic oil 13 in the lower fluid chamber 32 is kept substantially constant.
Accordingly, when the damping force variable damper 10 is extended, the sign of the pressure difference between the hydraulic oil 13 in the upper fluid chamber 31 and the hydraulic oil 13 in the lower fluid chamber 32 is reversed with respect to the compression of the variable damping force damper 10. To do.

As described above, when the pressure difference between the hydraulic oil 13 in the upper fluid chamber 31 and the hydraulic oil 13 in the lower fluid chamber 32 is reversed, the fluid passage 78 (see FIG. 5) is opened by the same mechanism as that during compression. Difficult to do.
Therefore, the piezoelectric body storage chamber 66 is partitioned off with respect to the piston space 67 by the bellows 51 or the like.

  As shown in FIG. 9A, in the state where the fluid passage 78 is closed by the valve body 107, the upper fluid chamber 31 (piston space 67) is slid by sliding the piston assembly 14 upward as indicated by the arrow H. , The hydraulic pressure Po2 increases.

Here, the piezoelectric body chamber 66 is partitioned off with respect to the piston space 67 by a bellows 51 or the like. Further, the piezoelectric body storage chamber 66 communicates with the external space of the damping force variable damper 10.
Therefore, the internal pressure (that is, atmospheric pressure) of the piezoelectric material storage chamber 66 is suppressed to be lower than the operating hydraulic pressure of the upper fluid chamber 31.
The pressure acting on the upper surface 91a of the piezoelectric / bellows connecting portion 91 is kept low by keeping the internal pressure of the piezoelectric body chamber 66 low.

Thereby, the pressing force Fo2 acts on the second pressure receiving portion 91b of the piezoelectric / bellows connecting portion 91.
The piezoelectric body 56 is compressed when the pressing force Fo2 acting on the second pressure receiving portion 91b exceeds the balance load Fb2.
Here, the balance load Fb <b> 2 is a pressing force acting by the extension of the piezoelectric body 56.

As shown in FIG. 9B, the outer peripheral edge 105 a of the valve sliding portion 105 is kept in contact with the inner peripheral edge 101 a of the valve restricting portion 101.
Therefore, the piezoelectric means 56 is compressed by the pressing force Fo2 (see FIG. 9A), so that the valve means 62 can be reliably raised as shown by the arrow I.
As the valve means 62 rises, the valve body 107 of the valve means 62 rises in the direction away from (separates from) the fluid passage 78 as shown by the arrow I, so that the fluid passage 78 can be satisfactorily opened.

When the fluid passage 78 is opened, the hydraulic oil 13 in the piston space 67 is guided to the lower fluid chamber 32 through the fluid passage 78 as indicated by an arrow J.
The hydraulic oil 13 in the piston space 67 is guided to the lower fluid chamber 32, whereby the hydraulic oil 13 in the upper fluid chamber 31 is guided to the piston space 67 as indicated by an arrow K through the piston opening 37.
That is, when the fluid passage 78 is opened, the hydraulic oil 13 in the upper fluid chamber 31 is smoothly guided to the lower fluid chamber 32 through the fluid passage 78.

Thereby, when the damping force variable damper 10 extends and the piston assembly 14 slides upward, the hydraulic oil 13 in the upper fluid chamber 31 can be smoothly guided to the lower fluid chamber 32 via the fluid passage 78. .
Thus, by smoothly flowing the hydraulic oil 13 through the fluid passage 78, a damper damping force determined by the pressing force Fo2 (see FIG. 9A) is obtained.

6 to 9, the example in which a constant voltage is applied to the piezoelectric body 56 has been described. However, the voltage applied to the piezoelectric body 56 can be adjusted (changed).
That is, the extension amount of the piezoelectric body 56 can be adjusted by adjusting (changing) the voltage applied to the piezoelectric body 56 by the control unit 22 shown in FIG.

Thus, the pressing force of the piezoelectric body 56 to the valve means 62 can be changed by adjusting the extension amount of the piezoelectric body 56.
By changing the pressing force to the valve means 62, the balance state Fb1 (see FIG. 7A) and the balance load Fb2 (see FIG. 9A) are changed by changing the compression state of the valve urging spring 65 (see FIG. 9A). Adjust).

The balance load Fb1 and the balance load Fb2 can be adjusted by changing the pressing force applied to the valve means 62 by the piezoelectric body 56.
Thereby, the damping force can be changed by changing the pressing force applied to the valve means 62 by the piezoelectric body 56.

Here, some damping force variable dampers are known in which the damping force is changed by adjusting the opening area of the fluid passage by applying a voltage to the piezoelectric body to expand and contract the piezoelectric body.
However, in order to adjust the opening area of the fluid passage by the expansion and contraction of the piezoelectric body, it is necessary to accurately control the voltage applied to the piezoelectric body, and the control for applying the voltage to the piezoelectric body is complicated.

On the other hand, the damping force variable damper 10 according to the first embodiment can change the damping force by changing the pressing force applied to the valve means 62 by the piezoelectric body 56.
Therefore, unlike the conventional damping force variable damper, it is not necessary to adjust the amount of movement of the valve means 62 by the piezoelectric body 56 with higher precision than necessary.
Since highly accurate adjustment of the valve means 62 can be eliminated, it is not necessary to accurately control the voltage applied to the piezoelectric body 56 when the valve means 62 is moved.

As a result, the voltage applied to the piezoelectric body 56 can be easily controlled, and the damping force of the damping force variable damper 10 can be changed by simple control.
In particular, as an example, the relationship between the voltage applied to the piezoelectric body 56 and the damping force obtained according to the voltage is mapped, and the adjustment of the damping force can be controlled more easily by using this characteristic map or the like. It is.

Meanwhile, in the damping force variable damper 10 shown in FIG. 1, road surface vibration acts as a reaction force on the piezoelectric body 56 while the vehicle 11 is traveling.
When the road surface vibration acts as a reaction force on the piezoelectric body 56, the piezoelectric body 56 is displaced and a voltage (electric power) is generated in the piezoelectric body 56.

Specifically, the piezoelectric body storage chamber 66 is partitioned off from the piston space 67 by the bellows 51 or the like, so that the internal pressure (atmospheric pressure) of the piezoelectric body storage chamber 66 is lower than the operating hydraulic pressure of the upper fluid chamber 31. It is suppressed.
Therefore, when the pressing force Fo2 (see FIG. 9A) acts on the second pressure receiving portion 91b of the piezoelectric / bellows connecting portion 91, the piezoelectric body 56 can be favorably compressed.

As a result, the piezoelectric body 56 can be displaced and a voltage (electric power) can be suitably generated in the piezoelectric body 56.
Thus, the voltage (electric power) generated by the piezoelectric body 56 can be stored (regenerated) in the power source 24.

Next, the damping force variable damper 120 according to the second embodiment will be described with reference to FIGS.
In addition, in the damping force variable damper 120 of Example 2, the same code | symbol is attached | subjected about the same / similar member as the damping force variable damper 10 of Example 1, and description is abbreviate | omitted.

A damping force variable damper 120 according to the second embodiment will be described.
As shown in FIG. 10, the damping force variable damper 120 is obtained by replacing the piston case 35 and the valve means 62 of the first embodiment with a piston case (piston) 121 and a valve means 131, respectively, and other configurations are the same as those of the first embodiment. This is the same as the damping force variable damper 10.
Here, the piston assembly of the second embodiment is different from the piston assembly 14 of the first embodiment, but in order to facilitate understanding of the configuration, the piston assembly 14 will be described as in the first embodiment.

  The piston case 121 is obtained by replacing the peripheral wall 36 and the piston bottom portion 75 of the first embodiment with the peripheral wall 122 and the piston bottom portion 123, respectively, and the other configurations are the same as the piston case 35 of the first embodiment.

  The peripheral wall 122 includes a pair of upper fluid passages (fluid passages) 126 that are curvedly extended in the circumferential direction of the peripheral wall, and a pair of lower fluid passages (fluid passages) 128 provided below the pair of upper fluid passages 126. Have

  The pair of upper fluid passages 126 are formed at an interval of 180 ° in the circumferential direction of the peripheral wall.

  The pair of lower fluid passages 128 are provided below the pair of upper fluid passages 126, and are formed at an interval of 180 °, like the pair of upper fluid passages 126.

As described above, the upper and lower fluid passages 126 and 128 are extended in the curved shape in the peripheral wall 122, so that a large length dimension of the upper and lower fluid passages 126 and 128 can be secured.
Furthermore, upper and lower fluid passages 126 and 128 are formed in the peripheral wall 122 in a plurality of stages (for example, two stages).
By ensuring a large length dimension of the upper and lower fluid passages 126 and 128 and further forming the upper and lower fluid passages 126 and 128 in a plurality of stages, a large selection range of the opening area of the fluid passage can be ensured.

By ensuring a large selection range of the opening area of the fluid passage, the damping force of the damping force variable damper 120 can be suitably changed even when the expansion / contraction amount of the piezoelectric body 56 is kept small.
Furthermore, the degree of freedom in design can be increased by ensuring a large selection range of the opening area of the fluid passage.

By providing a pair of upper fluid passages 126 and a pair of lower fluid passages 128 in the peripheral wall 122, the piston space 141 in the piston case 121 is communicated with the lower fluid chamber 32 via the upper and lower fluid passages 126, 128.
Therefore, the lower fluid chamber 32 communicates with the upper fluid chamber 31 through the upper and lower fluid passages 126 and 128, the piston space 141 and the piston opening 37.

The piston bottom 123 is a member that is provided in a lower portion 122 a of the lower fluid passage 128 in the peripheral wall 122 and partitions the piston space 141 from the lower fluid chamber 32.
Valve means 131 is placed on the piston bottom 123.

  The valve means 131 is supported by the piezoelectric / bellows connection part (valve support member) 132 provided on the piezoelectric body 56 side, the displacement transmission means 133 connected to the piezoelectric / bellows connection part 132, and the displacement transmission means 133. A valve member 134, a valve urging means 135 capable of pressing the valve member 134 toward the upper and lower fluid passages 126, 128, and a valve return means 136 capable of regulating the valve member 134 are provided.

The piezoelectric / bellows coupling portion 132 is the same member as the piezoelectric / bellows coupling portion 91 of the first embodiment.
A pressing rod 145 of the displacement transmitting means 133 is suspended downward from the lower center 132a of the piezoelectric / bellows connecting portion 132.
The piezoelectric / bellows connecting portion 132 is provided on the piezoelectric body 56 side, and can be displaced in the expansion / contraction direction corresponding to the expansion / contraction of the piezoelectric body 56.

The displacement transmitting means 133 includes a pressing rod 145 that is coaxially projected downward from the piezoelectric / bellows connecting portion 132 and a pair of displacement transmitting portions 151 provided on both sides of the pressing rod 145.
The pressing rod 145 has a wedge part 148 at the lower end.

As shown in FIG. 11, a pair of inclined guide portions 149 is formed in the wedge portion 148 by having the wedge portion 148 at the lower end portion of the pressing rod 145.
The pair of inclined guide portions 149 are formed in an upward gradient from the center of the pressing rod 145 toward the outside.
Therefore, by pushing down the pressing rod 145, the pair of displacement transmitting portions 151 can be moved toward the peripheral wall 122 (see FIG. 10) by the pair of inclined guide portions 149, respectively.

As shown in FIG. 10, the pair of displacement transmission parts 151 are provided on both sides of the pressing rod 145.
The inclined guide portion 149 of the pressing rod 145 is in contact with the inclined bottom portions 151a (see FIG. 11A) of the pair of displacement transmitting portions 151.
Therefore, as shown in FIG. 11B, the displacement transmitting portion 151 can be moved toward the peripheral wall 122 (see FIG. 10) by pushing down the inclined guide portion 149 of the wedge portion 148.
As shown in FIG. 10, a valve member 134 is connected to the displacement transmission unit 151.
The inclined bottom portion 151a and the inclined guide portion 149 will be described in detail later.

  The valve member 134 is movably mounted on the guide plate 161 placed on the pair of displacement transmitting portions 151, the pair of upper regulating members 162 movably disposed on the lower side of the guide plate 161, and the piston bottom portion 123. And a valve main body 164 connected to the upper restriction member 162 and the lower restriction member 163.

As shown in FIG. 12, the pair of valve main bodies 164 are formed in a curved shape along the peripheral wall 122, and are arranged at a predetermined interval S with respect to the peripheral wall 122.
The valve body 164 is movably supported with respect to the displacement transmitting portion 151 via upper and lower regulating members 162 and 163 (see FIG. 10), and can open and close the upper and lower fluid passages 126 and 128 (see also FIG. 10). It is a member.

Specifically, the valve main body 164 includes upper and lower closing portions (first pressure receiving portions) 166 and 167 provided on the curved outer peripheral wall 164a.
The upper closing portion 166 is formed in a curved shape along the curved outer peripheral wall 164 a at the upper end portion of the valve body 164.
The lower closing portion 167 is formed in a curved shape along the curved outer peripheral wall 164 a at the lower end portion of the valve body 164.

By pressing the valve body 164 toward the peripheral wall 122, the upper fluid passage 126 is closed by the upper closing portion 166, and the lower fluid passage 128 is closed by the lower closing portion 167.
Valve urging means 135 is provided on the inner wall 164 b of the valve body 164.

The valve urging means 135 includes a support rod portion 176 that protrudes radially inward from the approximate center of the inner wall 164b, and a valve urging spring 177 that is supported by the support rod portion 176.
The valve urging spring 177 is interposed between the valve main body 164 and the displacement transmitting portion 151 (see FIG. 10).

As shown in FIGS. 10 and 12, the valve body 164 is pressed toward the peripheral wall 122 (upper and lower fluid passages 126 and 128) by the urging force of the valve urging spring 177.
In this state, the urging force of the valve urging spring 177 holds the lower restricting member 163 in the connected state below the displacement transmitting portion 151, and the upper restricting member 162 in the connected state above the displacement transmitting portion 151. Yes.

The movement of the valve body 164 due to the urging force of the valve urging spring 177 is restricted by the upper and lower restricting members 162 and 163.
Thereby, the valve body 164 (upper and lower closing portions 166 and 167) is arranged at the restriction position P2 by the upper and lower restriction members 162 and 163.

By disposing the valve main body 164 at the restriction position P2, the valve main body 164 (upper and lower closing portions 166 and 167) is separated from the peripheral wall 122 (specifically, the upper and lower fluid passages 126 and 128) by a predetermined distance S ( (See FIG. 12).
In this state, by pressing the valve body 164 toward the peripheral wall 122, the upper and lower fluid passages 126 and 128 are closed by the upper and lower closing portions 166 and 167.

  As shown in FIGS. 10 and 12, the valve return means 136 includes a pair of contact portions 181 disposed along the outer peripheral wall 164 a of the valve body 164 and a pair of contact portions provided on each contact portion 181. A rod portion 182 and a pair of return springs 183 supported by the pair of contact rod portions 182 are provided.

The contact portion 181 is disposed between the upper and lower closing portions 166 and 167 of the valve body 164 and is formed in a curved shape along the outer peripheral wall 164 a of the valve body 164.
By forming the contact part 181 in a curved shape, the outer peripheral wall 181 a of the contact part 181 is formed so as to be able to contact the peripheral wall 122.

The return spring 183 is a compression spring that is fitted into the contact rod portion 182 and interposed between the contact portion 181 and the displacement transmission portion 151.
The contact portion 181 is pressed against the peripheral wall 122 by the urging force of the return spring 183, and the valve member 134 is held on the peripheral wall 122.
Thus, by providing the valve return means 136, the valve member 134 can be prevented from moving in the axial direction of the piston case 121.

In addition, by providing the valve return means 136, the displacement transmitting portion 151 is pressed toward the pressing rod 145 by the urging force of the return spring 183.
Therefore, when the pressing rod 145 is raised from the state of FIG. 11B to the state of FIG. 11A, the displacement transmitting portion 151 is directed toward the pressing rod 145 by the urging force of the return spring 183 (return). Can be moved.
By moving the displacement transmitting portion 151, the upper and lower restricting members 162 and 163 can be moved (returned) toward the pressing rod 145 together with the displacement transmitting portion 151.

By moving the upper and lower restricting members 162 and 163, the valve main body 164 can be moved together with the upper and lower restricting members 162 and 163 in the direction of separating (separating) from the upper and lower fluid passages 126 and 128.
By moving the valve body 164, the upper and lower fluid passages 126, 128 can be opened by separating the upper and lower closing portions (first pressure receiving portions) 166, 167 from the upper and lower fluid passages 126, 128.

Next, the inclined bottom portion 151a and the inclined guide portion 149 will be described in detail.
As shown in FIG. 11A, the inclined guide portion 149 of the pressing rod 145 is in contact with the inclined bottom portion 151 a of the displacement transmitting portion 151.
The inclined bottom portion 151a and the inclined guide portion 149 are formed at an inclination angle θ.
Therefore, when the pressing rod 145 is pushed down, the displacement of the pressing rod 145 is transmitted in the direction orthogonal to the displacement direction by the inclined guide portion 149 and the inclined bottom portion 151a.

  As shown in FIG. 11B, the displacement of the pressing rod 145 is transmitted in a direction orthogonal to the displacement direction, so that the displacement transmitting portion 151 is pressed toward the peripheral wall 122 (see FIG. 10).

As shown in FIG. 10, when the displacement transmitting portion 151 moves toward the peripheral wall 122, the valve urging spring 177 (see FIG. 12) moves together with the displacement transmitting portion 151.
Therefore, the valve main body 164 moves toward the peripheral wall 122 together with the valve biasing spring 177.

As the valve main body 164 moves toward the peripheral wall 122, the upper fluid passage 126 is closed by the upper closing portion 166, and the lower fluid passage 128 is closed by the lower closing portion 167.
Thus, by providing the valve means 131 with the displacement transmission means 133, the displacement transmission means 133 can transmit the displacement of the piezoelectric / bellows coupling portion 132 (the pressing rod 145) in a direction orthogonal to the displacement direction.

Here, by making the inclination angle θ shown in FIG. 11 smaller than 45 °, the displacement amount δ2 of the displacement transmitting portion 151 can be ensured larger than the displacement amount δ1 of the pressing rod 145.
Therefore, the movement amount of the valve body 164 can be increased with respect to the expansion / contraction amount of the piezoelectric body 56 (see FIG. 10).

The inclination angle θ is preferably determined so as not to exceed 40 °.
By setting the inclination angle θ so as not to exceed 40 °, the movement amount of the valve body 164 can be sufficiently increased.

By increasing the movement amount of the valve body 164, a large maximum separation amount of the upper and lower closing portions 166 and 167 with respect to the upper and lower fluid passages 126 and 128 can be secured.
Thereby, since the flow volume (namely, flow-path cross-sectional area) of the hydraulic oil 13 which flows through the upper and lower fluid passages 126 and 128 can be changed in a wide range, the damping force of the damping force variable damper 120 can be suitably changed.

In addition, according to the damping force variable damper 120 of the second embodiment, the displacement transmission means 133 is provided in the valve means 131, so that the displacement of the piezoelectric / bellows connecting portion 132 is orthogonal to the displacement direction by the displacement transmission means 133. It can be transmitted in the direction.
The displacement direction of the piezoelectric / bellows connecting portion 132 is the same as the expansion / contraction direction of the piezoelectric body 56. Therefore, by providing the displacement transmission means 133, the pair of valve members 134 can be provided in a direction orthogonal to the expansion / contraction direction of the piezoelectric body 56.

As described above, by providing the pair of valve members 134 in the direction orthogonal to the expansion / contraction direction of the piezoelectric body 56, the amount of protrusion of the valve means 131 with respect to the piezoelectric body 56 in the axial direction can be reduced.
Thereby, since the length dimension to the axial direction of the piston assembly 14 can be restrained small, size reduction of the piston assembly 14 can be achieved and the freedom degree of design can be raised.

Next, an example in which a voltage is applied to the piezoelectric body 56 to close the pair of upper fluid passages 126 and the pair of lower fluid passages 128 with the valve means 131 (valve body 164) will be described with reference to FIG.
In FIG. 13, one upper fluid passage 126 and one lower fluid passage 128 will be described in order to facilitate understanding of the operation.

As shown in FIG. 13A, the valve main body 164 of the valve means 131 is pressed by the valve biasing spring 177 toward the upper and lower fluid passages 126 and 128.
In a state where the valve body 164 is pressed, the valve body 164 is held at the restriction position P2 by the lower restriction member 163 and the upper restriction member 162.

In this state, the control unit 22 is controlled to apply a voltage from the power supply 24 to the piezoelectric body 56 to extend the piezoelectric body 56 as indicated by an arrow L.
As the piezoelectric body 56 expands, the piezoelectric / bellows connecting portion 132 descends as shown by an arrow M.
When the piezoelectric / bellows connecting portion 132 is lowered, the pressing rod 145 is lowered toward the piston bottom portion 123 together with the piezoelectric / bellows connecting portion 132 as shown by an arrow M.

Here, the inclined guide portion 149 of the pressing rod 145 is in contact with the inclined bottom portion 151 a of the displacement transmitting portion 151.
Accordingly, when the pressing rod 145 is lowered, the inclined bottom portion 151a of the displacement transmitting portion 151 is pressed by the inclined guide portion 149 of the pressing rod 145.
As a result, the displacement transmitting portion 151 moves as indicated by an arrow N toward the peripheral wall 122.

As shown in FIG. 13 (b), the displacement transmitting portion 151 moves toward the peripheral wall 122, so that the valve body 164 moves as indicated by the arrow N toward the upper and lower fluid passages 126 and 128.
As the valve main body 164 moves, the upper fluid passage 126 is pressed by the upper closing portion (first pressure receiving portion) 166 of the valve main body 164, and the lower fluid passage 128 is pressed by the lower closing portion (first pressure receiving portion) 167. be able to.
Thereby, the upper fluid passage 126 can be closed by the upper closing portion 166, and the lower fluid passage 128 can be closed by the lower closing portion 167.

Next, an example in which the damping force is obtained by sliding the piston assembly 14 when the damping force variable damper 120 expands and contracts will be described with reference to FIGS.
First, an example in which the damping force is obtained by sliding the piston assembly 14 downward when the damping force variable damper 120 contracts (compresses) will be described with reference to FIG.

As shown in FIG. 14A, the upper fluid passage 126 is closed by the upper closing portion 166 and the lower fluid passage 128 is closed by the lower closing portion 167 in a state where a voltage is applied to the piezoelectric body 56.
In this state, the damping force variable damper 120 contracts (compresses) when the compression force acts on the damping force variable damper 120.
As the damping force variable damper 120 contracts, the piston assembly 14 and the free piston 17 (see FIG. 6) slide downward as indicated by an arrow O.

By sliding the piston assembly 14 downward, the volume of the upper fluid chamber 31 increases, and the hydraulic pressure of the hydraulic oil 13 in the upper fluid chamber 31 decreases.
Therefore, a relatively large pressure difference between the hydraulic oil 13 in the upper fluid chamber 31 and the hydraulic oil 13 in the lower fluid chamber 32 (that is, the differential pressure Po3) can be secured.

The pressing force Fo3 acts on the upper and lower blocking portions (first pressure receiving portions) 166 and 167 by the differential pressure Po3 secured relatively large.
When the pressing force Fo3 acting on the upper and lower closing portions (first pressure receiving portions) 166, 167 exceeds the balance load Fb3, the valve urging spring 177 is compressed.
Here, the balance load Fb3 is a load acting on the valve biasing spring 177 in a compressed state (that is, a force pressing the valve body 164 with the valve biasing spring 177).

As shown in FIG. 14B, the valve urging spring 177 is compressed, so that the valve main body 164 is pressed in the direction away from the upper and lower fluid passages 126 and 128 as indicated by an arrow P.
Therefore, the upper and lower closing portions (first pressure receiving portions) 166 and 167 are separated (separated) from the upper and lower fluid passages 126 and 128, and the upper and lower fluid passages 126 and 128 are opened.
As the upper and lower fluid passages 126 and 128 are opened, the hydraulic oil 13 in the lower fluid chamber 32 is guided to the piston space 141 through the upper and lower fluid passages 126 and 128 as indicated by an arrow Q.
The hydraulic oil 13 guided to the piston space 141 is guided to the outside of the peripheral wall 122 (that is, the upper fluid chamber 31 (see FIG. 14A)) through the piston opening 37 (see FIG. 14A).

As a result, when the damping force variable damper 120 contracts and the piston assembly 14 slides downward, the hydraulic oil 13 in the lower fluid chamber 32 passes smoothly through the upper and lower fluid passages 126 and 128 to the upper fluid chamber 31. Can lead.
Thus, by smoothly flowing the hydraulic oil 13 through the upper and lower fluid passages 126 and 128, a damper damping force determined by the pressing force Fo3 (see FIG. 14A) is obtained.

  Next, an example in which the damping force is obtained by sliding the piston assembly 14 upward when the damping force variable damper 120 extends will be described with reference to FIG.

As shown in FIG. 15A, the upper fluid passage 126 is closed by the upper closing portion 166 and the lower fluid passage 128 is closed by the lower closing portion 167 in a state where a voltage is applied to the piezoelectric body 56.
In this state, the damping force variable damper 120 is extended by a tensile force acting on the damping force variable damper 120.
As the damping force variable damper 120 extends, the piston assembly 14 and the free piston 17 (see FIG. 8) slide upward as indicated by the arrow R.

As the piston assembly 14 slides, the volume of the upper fluid chamber 31 (see also FIG. 8) decreases, and the hydraulic pressure of the hydraulic oil 13 in the upper fluid chamber 31 increases.
On the other hand, when the piston assembly 14 and the free piston 17 slide upward, the volume change of the lower fluid chamber 32 accompanying the sliding of the piston assembly 14 is absorbed by the gas chamber 33 (see FIG. 8). .

Accordingly, the hydraulic pressure of the hydraulic oil 13 in the lower fluid chamber 32 is kept substantially constant.
Accordingly, when the damping force variable damper 10 is extended, the sign of the pressure difference between the hydraulic oil 13 in the upper fluid chamber 31 and the hydraulic oil 13 in the lower fluid chamber 32 is reversed with respect to the compression of the variable damping force damper 10. To do.
As described above, when the pressure difference between the hydraulic oil 13 in the upper fluid chamber 31 and the hydraulic oil 13 in the lower fluid chamber 32 is reversed, the upper and lower fluid passages 126 and 128 are opened by the same mechanism as that during compression. It becomes difficult.

Therefore, the piezoelectric material storage chamber 66 is partitioned off with respect to the piston space 141 by the bellows 51 or the like.
The piezoelectric body storage chamber 66 is maintained at atmospheric pressure by communicating with the external space.

Therefore, the internal pressure (atmospheric pressure) of the piezoelectric body storage chamber 66 is suppressed to be lower than the operating hydraulic pressure of the upper fluid chamber 31.
The pressure acting on the upper surface 132b of the piezoelectric / bellows connecting portion 132 is suppressed to a low level by suppressing the internal pressure of the piezoelectric body storage chamber 66 to a low level.
Accordingly, the pressing force Fo4 acts on the second pressure receiving portion 132c of the piezoelectric / bellows connecting portion 132.

The second pressure receiving portion 132 c is formed on the lower surface of the piezoelectric / bellows coupling portion 132.
The piezoelectric body 56 is compressed when the pressing force Fo4 acting on the second pressure receiving portion 132c exceeds the balance load Fb2.
Here, the balance load Fb <b> 2 is a pressing force acting by the extension of the piezoelectric body 56.

As shown in FIG. 15B, the pressure rod 145 rises as shown by the arrow S by the piezoelectric body 56 being compressed.
As the pressing rod 145 rises, the displacement transmitting portion 151 moves as indicated by an arrow T toward the pressing rod 145 by the urging force of the return spring 183 provided in the valve return means 136.
As the displacement transmission unit 151 moves, the upper and lower regulating members 162 and 163 move as indicated by an arrow T together with the displacement transmission unit 151.

As the upper and lower restricting members 162 and 163 move, the valve body 164 moves as indicated by the arrow T together with the upper and lower restricting members 162 and 163.
When the valve body 164 moves, the upper and lower closed portions (first pressure receiving portions) 166 and 167 are separated (separated) from the upper and lower fluid passages 126 and 128, and the upper and lower fluid passages 126 and 128 are opened.

As the upper and lower fluid passages 126 and 128 are opened, the hydraulic oil 13 in the piston space 141 is guided to the lower fluid chamber 32 through the upper and lower fluid passages 126 and 128 as indicated by an arrow U.
The hydraulic oil 13 in the piston space 141 is guided to the lower fluid chamber 32, so that the hydraulic oil 13 in the upper fluid chamber 31 (see FIG. 15A) enters the piston opening 37 in the piston space 141 (see FIG. 15A). )
That is, when the upper and lower fluid passages 126 and 128 are opened, the hydraulic oil 13 in the upper fluid chamber 31 is smoothly guided to the lower fluid chamber 32 through the upper and lower fluid passages 126 and 128.

As a result, when the damping force variable damper 120 extends and the piston assembly 14 slides upward, the hydraulic oil 13 in the upper fluid chamber 31 passes smoothly through the upper and lower fluid passages 126 and 128 to the lower fluid chamber 32. Can lead.
Thus, by smoothly flowing the hydraulic oil 13 through the upper and lower fluid passages 126 and 128, a damper damping force determined by the pressing force Fo4 (see FIG. 15A) is obtained.

14 and 15, the example in which a constant voltage is applied to the piezoelectric body 56 has been described. However, as in the first embodiment, the voltage applied to the piezoelectric body 56 can be adjusted (changed). .
That is, the extension amount of the piezoelectric body 56 can be adjusted by adjusting (changing) the voltage applied to the piezoelectric body 56 by the control unit 22 shown in FIG.

Thus, the pressing force of the piezoelectric body 56 on the valve means 131 can be changed by adjusting the extension amount of the piezoelectric body 56.
By changing the pressing force to the valve means 131, the compression state of the valve urging spring 177 is changed to change the balance load Fb3 (see FIG. 14A) and the balance load Fb2 (see FIG. 15A) (see FIG. 15A). Adjust).
Thus, when the upper and lower fluid passages 126 and 128 are opened by expansion and contraction of the damping force variable damper 120, the load for opening the upper and lower fluid passages 126 and 128, that is, the hydraulic pressure (hydraulic pressure) of the upper fluid chamber 31 is adjusted. Thus, the damper damping force can be adjusted (changed).

Thus, the damping force can be changed by changing the pressing force applied to the valve means 131 by the piezoelectric body 56.
Therefore, as explained in the prior art, it is not necessary to adjust the amount of movement of the valve means 131 by the piezoelectric body 56 with higher precision than necessary.
Since high-precision adjustment of the valve means 131 can be eliminated, it is not necessary to accurately control the voltage applied to the piezoelectric body 56 when the valve means 131 is moved.

As a result, the voltage applied to the piezoelectric body 56 can be easily controlled, and the damping force of the damping force variable damper 120 can be changed by simple control.
In particular, as an example, the relationship between the voltage applied to the piezoelectric body 56 and the damping force obtained according to the voltage is mapped, and the adjustment of the damping force can be controlled more easily by using this characteristic map or the like. It is.

  As described above, according to the damping force variable damper 120 of the second embodiment, it is possible to obtain an effect that the damping force can be suitably changed, like the damping force variable damper 10 of the first embodiment.

The damping force variable damper according to the present invention is not limited to the above-described embodiments, and can be changed or improved as appropriate.
For example, in the first and second embodiments, the example in which the gas chamber 33 is adjacent to the lower fluid chamber 32 of the damping force variable dampers 10 and 120 has been described. However, the present invention is not limited to this. It is also possible to provide.
The air chamber is filled with high-pressure air

In the second embodiment, the example in which the upper and lower fluid passages 126 and 128 are provided in two stages has been described. However, the present invention is not limited to this, and it may be formed in other plural stages such as three stages.
It is also possible to form the fluid passage in a single stage.

  Furthermore, in the second embodiment, the example in which the pair of upper fluid passages 126 are formed at an interval of 180 ° and the pair of lower fluid passages 128 is formed at an interval of 180 ° has been described. Instead, the upper fluid passage 126 and the lower fluid passage 128 may be formed at other intervals such as 120 °.

  Further, the damping force variable dampers 10 and 120, the vehicle 11, the cylinder 12, the piston assembly 14, the piston cases 35 and 121, the piezoelectric body 56, the valve means 62 and 131, and the valve support member 63 shown in the first and second embodiments. , Valve members 64 and 134, valve urging springs 65 and 177, fluid passage 78, piezoelectric / bellows connecting portion 91, valve restricting portion 101, upper and lower fluid passages 126 and 128, piezoelectric / bellows connecting portion 132, displacement transmission means 133 The shapes and configurations of the valve urging means 135, the upper restricting member 162, and the lower restricting member 163 are not limited to those illustrated, and can be appropriately changed.

  INDUSTRIAL APPLICABILITY The present invention is suitable for application to an automobile equipped with a damping force variable damper that is used in a vehicle suspension device and can vary the damping force by sliding a piston in a cylinder.

DESCRIPTION OF SYMBOLS 10,120 ... Damping force variable damper, 11 ... Vehicle, 12 ... Cylinder, 13 ... Hydraulic oil (fluid), 14 ... Piston assembly, 31 ... Upper fluid chamber (first fluid chamber), 32 ... Lower fluid chamber (first) 2 fluid chamber), 35, 121 ... piston case (piston), 51 ... metal bellows, 56 ... piezoelectric body, 62, 131 ... valve means, 63 ... valve support member, 64, 134 ... valve member, 65 ... valve biasing Spring (valve urging means), 67 ... Piston space, 78 ... Fluid passage, 91 ... Piezoelectric / bellows connecting portion, 101 ... Valve restricting portion (regulating portion), 126 ... Upper fluid passage (fluid passage), 128 ... Lower fluid Path (fluid path), 132 ... piezoelectric / bellows coupling part (valve support member), 133 ... displacement transmitting means, 135 ... valve urging means, 162 ... up regulating member (regulating part), 163 ... bottom regulating member (regulating part) 177: Valve biasing spring.

Claims (3)

In a damping force variable damper that is used in a vehicle suspension system and can change damping force,
A cylinder filled with fluid;
A piston slidably housed in the cylinder to divide the cylinder into first and second fluid chambers, and a fluid passage that communicates the first and second fluid chambers;
Valve means provided in the piston, capable of closing the fluid passage by pressing toward the fluid passage, and capable of opening the fluid passage when the piston slides;
A force connected to the valve means and partitioned from one of the first and second fluid chambers to press the valve means toward the fluid passage in response to an applied voltage. A piezoelectric body that can be changed,
When the piston slides so that the hydraulic pressure of one of the first and second fluid chambers is lowered, the valve has a pressure difference between the fluid in the first fluid chamber and the fluid in the second fluid chamber. Allowing the fluid passage to be opened by separating means from the fluid passage;
When the piston slides so that the hydraulic pressure of one of the first and second fluid chambers is increased, the valve means is moved away from the fluid passage with the increased hydraulic pressure to move the fluid. The passage can be opened,
A cylindrical piston case sliding inside the cylinder of the piston has a piston space inside,
The piezoelectric body connected to the valve means is stored in a piezoelectric body storage chamber provided in the piston space,
The piezoelectric housing chamber is a space provided between the piston case and the valve means and surrounded by a metal bellows, and is partitioned in a sealed state with respect to the piston space. It is held at a lower pressure than the hydraulic fluid in the first fluid chamber by being held at atmospheric pressure.
This is a variable damping force damper. The valve means includes
A valve support member provided on the piezoelectric body side;
A valve member supported movably on the valve support member and capable of opening and closing the fluid passage;
Valve urging means capable of closing the fluid passage with the valve member by pressing the valve member toward the fluid passage;
With
The valve support member is
The damping force variable damper according to claim 1, further comprising a restricting portion that restricts movement of the valve member by an urging force of the valve urging means. The valve means includes
A valve support member provided on the piezoelectric body side and displaceable in an expansion / contraction direction corresponding to expansion / contraction of the piezoelectric body;
Displacement transmitting means capable of transmitting the displacement of the valve support member in a direction perpendicular to the displacement direction;
A valve member supported movably by the displacement transmission means and capable of opening and closing the fluid passage;
Valve urging means capable of closing the fluid passage with the valve member by pressing the valve member toward the fluid passage;
The damping force variable damper according to claim 1, further comprising:

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