JP2578566Y2 - Damping force adjustment device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a damping force adjusting device which adjusts a main damping force generated by a leaf valve by changing a peripheral end bending amount of the leaf valve as a damping valve using a piezoelectric element. Regarding improvement.

[0002]

2. Description of the Related Art As a conventional damping force adjusting device for a hydraulic shock absorber, a main damping force generated by the leaf valve is changed by adjusting a bending amount of a peripheral end of a leaf valve which is a damping valve by applying a voltage to a piezoelectric element. Such a configuration is proposed in, for example, Japanese Utility Model Laid-Open No. 62-149645. This proposal is based on the application of a voltage to a piezoelectric element as an electrostrictive member.
When the piezoelectric element expands, the expansion force directly adjusts the amount of bending at the peripheral end of a leaf valve as a damping force valve for generating a damping force, thereby adjusting the damping force generated by the valve. .

[0003]

However, in this prior art, the amount of deflection at the peripheral end of the leaf valve cannot be changed beyond the amount of expansion of the piezoelectric element, and a large amount of deflection is required at the peripheral end of the leaf valve. In such a case, the amount of piezoelectric elements to be installed in series must be greatly increased. In this case,
There is a problem in that the axial length of the entire damping force adjusting device is greatly increased.

The present invention has been made in view of the above problems, and its purpose is to increase the amount of deflection at the peripheral end of a leaf valve, which is a damping valve, as compared with the amount of expansion of a piezoelectric element. Another object of the present invention is to provide a damping force adjusting device capable of increasing the damping force of the leaf valve by utilizing the electrostrictive action of the piezoelectric element.

[0005]

A damping force adjusting device according to the present invention comprises a piston rod inserted into a cylinder, a piston body attached to the piston rod and sliding into the cylinder, and a piston body. The extension side damping valve and the compression side damping valve arranged to be openable and closable at each end of the extension side port and the compression side port penetrating therethrough, and are provided on the piston body so as to communicate with the extension side port and the compression side port, respectively. The expansion-side throttle port and the compression-side throttle port, and a expansion-side throttle port that is disposed in a tip spigot member attached to the tip of the piston rod and adjusts the flow of hydraulic oil flowing from the expansion-side throttle port and the compression-side throttle port. 1 sub-valve and compression-side first sub-valve, the expansion-side throttle port and compression-side throttle port, and the expansion-side throttle port corresponding thereto. And the back pressure chamber of the extension side damping valve and the compression side damping valve provided so as to communicate with the oil passage connecting the back surface of the sub-valve and the compression side first sub valve,
A piezoelectric element provided in the piston rod so as to face the extension-side first sub-valve and the compression-side first sub-valve, wherein the extension-side first sub-valve and the compression-side first sub-valve are set by electrostriction of the piezoelectric element. By changing the load in proportion to the energizing voltage, the pressure in each of the back pressure chambers is changed to adjust the damping force.

[0006]

In the present invention, when the piston rod slides in the cylinder, the hydraulic oil from the upstream oil chamber receives the main damping force via the oil passage connecting each throttle port and the corresponding first sub-valve. As well as reaching the back side of each leaf valve that generates the pressure, it also extends to the pressure receiving surface side of each leaf valve, the hydraulic oil passes by bending the peripheral end of each leaf valve, and the extension side and the compression side , Respectively.

At this time, when a predetermined voltage is applied to the piezoelectric element, the amount of deflection of each peripheral end of each of the first sub-valves is adjusted in a direction to close them according to the magnitude of the applied voltage. Therefore, the back pressure in each leaf valve is adjusted in the direction of increasing, and the damping force generated in each leaf valve is adjusted in the direction of increasing, respectively. It can be changed so that it becomes higher with a width larger than the expansion amount of the element.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 denotes a cylinder.
A piston rod 2 is inserted into the cylinder 1 so as to be able to protrude and retract, and the lower end of the piston rod 2 slides in the cylinder 1 while a rod-side oil chamber A and a piston-side oil chamber B are formed in the cylinder 1. It has a piston portion 3 that forms a compartment. Further, a piezoelectric element 4 as an electrostrictive member is disposed in a through hole 2 a formed in the shaft core of the piston rod 2.

Although not shown, a lead wire is connected to the piezoelectric element 4, and the end of the lead wire projects outside from the rear end, which is the upper end of the piston rod 2. And
The piezoelectric element 4 expands when a predetermined voltage is applied thereto, and changes and adjusts the main damping forces on the expansion side and the compression side, respectively, by the expansion force. The above-mentioned expansion force is applied to the piezoelectric element 4.
Acts so that only the tip of the lower part moves downward.

The piston rod 2 is provided with a front spigot member 20 at the front end 2b thereof, and the piston 3 is interposed on the outer periphery of the front spigot member 20. The piston part 3 is a piston body 3 that slides in the cylinder # 1.
0, a compression-side leaf valve 5 as a compression-side damping valve and a compression-side leaf valve 6 as a main expansion-side damping valve are provided so as to sandwich the piston body 30.

The extension side leaf valve 5 is disposed so as to close the lower end opening of the extension side port 30a opened in the piston body 30, and the compression side leaf valve 6 is opened in the piston body 30. It is arranged so as to close the upper end opening of the compression side port 30b.

Each of the leaf valves 5 and 6 is formed of an annular leaf valve, and is fixed in such a manner that the inner peripheral end is fixed and the outer peripheral end is free, and when the outer peripheral end bends, a main extension of a predetermined size is obtained. It generates a damping force on each side.

That is, the leaf valves 5 and 6 are
Each inner peripheral end is sandwiched between upper and lower end surfaces on the inner peripheral side of the piston main body 30, a spacer 50 disposed opposite to the upper and lower end surfaces, and a stepped portion 30g of the front spigot member. Adjacent to the outer peripheral end are upper and lower end surfaces on the outer peripheral side of the piston body 30 and valve stoppers 51 and 61 disposed to face the upper and lower end surfaces.

The valve stoppers 51, 61 press the outer peripheral ends of the leaf valves 5, 6 against upper and lower end surfaces on the outer peripheral side of the piston body 30 by the urging forces from the urging springs 52, 62, respectively. Each leaf valve 5,
The magnitude of the main damping force generated by each leaf valve 5, 6 is set by selecting the bending rigidity of 6.

In this embodiment, hydraulic chambers 53 and 63 are formed on the back side of the leaf valves 5 and 6, respectively, and these are the spacer 50, the front end spigot member 20, and the valve stoppers 51 and 61. And housings 54 and 64 for accommodating the valve stoppers 51 and 61.

The hydraulic chambers 53 and 63 communicate with the inside of the front spigot member 20 via the communication holes 50a formed in the spacers 50 and 60 and the communication holes 21b and 21c of the front spigot member 20, respectively. ing.

The tip spigot member 20 has a back surface of each of the leaf valves 5 and 6, ie, back pressure passages 5a and 6 inside thereof.
a and the first extension side for supplying hydraulic pressure to the hydraulic chambers 53 and 63.
It has a sub-valve 7 and a pressure-side first sub-valve 8. That is, the front spigot member 20 includes the rod portion 21 on the lower end side and the connecting portion 22 on the upper end side integrally connected to the rod portion 21.

The sub-valves 7 and 8 are housed in a cylindrical inner space 21a formed inside the rod portion 21. Each of the sub-valves 7 and 8 is a piezoelectric element 4
In this embodiment, each of the sub-valves 7 and 8 is formed by an annular leaf valve, and when the outer peripheral end of the sub-valve 7 and 8 is bent.
Is set so as to allow the flow of the hydraulic oil through the control valve.

That is, the extension-side first sub-valve 7 is
As shown in FIG. 7, the inner peripheral back surface is placed or fixed on the annular seat portion 71a of the valve seat 71. Further, the extension-side first sub-valve 7 has an outer peripheral side seat portion 72b at the lower outer periphery of the valve spool 72 in contact with the outer peripheral side on the pressure receiving surface side which is the upper surface.

The valve spool 72 is provided in the inner space 21a.
And has an annular groove 72c between the extension-side first sub-valve 7 and the outer peripheral side seat portion 72b. A port 72d is formed in the annular groove 72c so as to pass through a thick portion on the top of the valve spool 72.

Therefore, the extension side first sub-valve 7 in this embodiment is strongly pressed against the outer peripheral side seat portion 72b by the lowering of the valve spool 72, and acts to close it strongly. Therefore, when hydraulic pressure acts on the peripheral end of the extension-side first sub-valve 7, it bends downward in the drawing, and a predetermined flow rate of hydraulic oil according to the above pressing strength is secured. .

Since the inner peripheral end of the extension-side first sub-valve 7 is held by the annular seat 71a, the inner peripheral end of the extension-side first sub-valve 7 is supported by the annular seat 71a as a fulcrum. The outer peripheral end of one sub-valve 7 is leveraged,
When pressed against the outer peripheral side seat 72b of the valve spool 72, the amount of deflection of the outer peripheral end of the extension-side first sub-valve 7 is changed, and the flow rate of hydraulic oil is changed to decrease via the outer peripheral end of the extension-side first sub-valve 7. You.

On the other hand, the pressure side first sub-valve 8 has an annular seat portion 8 of the slide shaft 10 on the inner peripheral back surface as an upper surface.
1a. Also, the pressure side first sub-valve 8
Is in contact with the outer peripheral side seat portion 82b at the upper end of the valve spool 72 on the pressure receiving surface which is the lower surface.

The valve spool 72 has an annular groove 82c between the pressure side first valve 8 and the outer peripheral side seat portion 82b, and a port 82d penetrating the thick portion of the valve spool 72 through the annular groove 82c. Is opened. For this reason, the pressure side first sub-valve 8 in this embodiment has its inner peripheral end side held by the annular seat portion 81a of the slide shaft 10 and its outer peripheral end pressed against the outer peripheral side seat portion 82b in a flexible manner. become.

Therefore, when the hydraulic pressure acts on the outer peripheral end of the pressure-side first sub-valve 8 pressure receiving surface, it bends upward, and at this time, a predetermined flow rate of hydraulic oil is secured.

Since the inner peripheral end side of the pressure side first sub-valve 8 is held by the annular seat portion 81a,
The outer peripheral end of the compression-side first sub-valve 8 has an outer peripheral side seat portion 82b.
When the outer peripheral end of the pressure-side first sub-valve 8 is positively pressed with the annular seat portion 81a as a fulcrum, the outer peripheral end of the pressure-side first sub-valve 8 is pressed against the outer peripheral-side seat portion 82b of the valve spool 72 by leverage movement. The amount of end deflection is changed.

Therefore, the flow rate of the hydraulic oil through the outer peripheral end of the pressure side first sub-valve 8 is adjusted to decrease. By the way, to the upstream side of each of the sub-valves 7 and 8, hydraulic oil flows into the piston main body 30 through the open port 30a and the compression port 30b, respectively.

That is, an extension side throttle port 30c is opened from the inner peripheral surface near the lower end of the piston main body 30 to the lower end surface of the piston main body 30, and the piston main body 30 is opened from the inner peripheral surface near the upper end of the piston main body 30. A pressure-side throttle port 30d is opened toward the upper end surface of the pressure-feed port 30.

Each of the throttle ports 30c and 30d communicates with communication holes 21d and 21e formed in the rod 21 adjacent to the inner peripheral surface of the piston main body 30, and through these communication holes 21d and 21e. And communicates with the inner space 21a of the rod portion 21. In addition, each aperture port 30
Reference numerals c and 30d denote annular grooves 30e and 30f respectively formed on the upper and lower end surfaces of the piston main body 30, and the ports 30a and 30d, respectively.
b.

Further, each of the aperture ports 30c, 30
d, the communication holes 21d and 21e, the oil passages 5a connecting the upstream sides of the sub-valves 7 and 8, and the back pressure chambers (X) and (Y) of the leaf valves 5 and 6 so as to communicate with the communication holes 21.
b, 50a and a communication hole 21c are provided.

Further, a steel ball 4 is provided between the slide shaft 10 and the block 42 locked at the end of the piezoelectric element 4.
Under the alignment structure of the steel balls 43, when a predetermined voltage is applied to the piezoelectric element 4, the expansion force generated by the piezoelectric element 4 acts on each of the above members.

On the other hand, a fastening member 92 having a cylindrical portion 91 is screwed into the outer periphery of the lower end of the rod portion 21. On the flange portion 92a of the fastening member 92, an urging spring 5 is provided.
The housing 54 for supporting the housing 2 with the valve stopper 51 is placed.

The valve rings 71 and 81 have ports 93a and 93b, respectively.
An extension-side second sub-valve 94 and a compression-side second sub-valve 95 as leaf valves are attached so as to close 3b.

The port 93a communicates with the piston-side oil chamber B through the extension second sub-valve 94 and the through hole 96a of the plug 96. The port 93b is connected to the pressure side second
It communicates with the rod-side oil chamber A via a communication hole 99 formed at the base end of the valve 95 and the rod portion 21. Each of these second sub-valves 94 and 95 is formed in a ring shape, and the inner peripheral end of the second sub-valve 94 and 95 has a seat portion 9 at the end of the valve ring 71 or 81.
7,98.

In the hydraulic shock absorber formed as described above, the ports 30a, 30b of the piston body 30
When the hydraulic oil passes through the throttle port 30, the hydraulic oil flows into the pressure-receiving surface side of each leaf valve 5, 6.
It extends to the pressure receiving surface side of each of the sub-valves 7 and 8 via c and 30d.

Further, the hydraulic oil at the ends flows into the back pressure chambers X and Y formed on the back side of the leaf valves 5 and 6 through the respective throttle ports 30c and 30d. 6, the amount of bending of the outer peripheral end is suppressed. The amount of bending of the outer peripheral end of each of the sub-valves 7, 8 is controlled by a predetermined voltage to the piezoelectric element 4, and the amount of bending of the outer peripheral end of each of the sub-valves 7, 8 is changed by applying a voltage to the piezoelectric element 4.

In this invention, the hydraulic pressure which has been supplied to the back pressure chambers X and Y of the leaf valves 5 and 6 rises by closing the sub-valves 7 and 8 more strongly by the electromagnetic action of the piezoelectric element 4. , The leaf valves 5 and 6 act more strongly in the closing direction, and the damping force increases. Conversely, when the voltage applied to the piezoelectric element 4 is reduced, the damping force generated in each of the leaf valves 5 and 6 is adjusted to decrease.

In other words, when the voltage is applied to the piezoelectric element 4, the leaf valves 5 and 6, which generate a predetermined damping force when the hydraulic shock absorber expands and contracts, have their inner peripheral end bending amounts changed, and the generated damping force is high. It will be adjusted so that.

In this case, when a voltage is applied to the piezoelectric element 4, the expansion force generated in the piezoelectric element 4 temporarily changes the amount of bending of the outer peripheral end of each sub-valve 7, 8 and causes The flow rate of the hydraulic oil passing through the outer peripheral end is restricted, thereby changing the flow rate of the hydraulic oil flowing into the back side of each leaf valve 5, 6 and changing each main damping force generated in each leaf valve 5, 6. Will do.

As a result, the amount of deflection of the outer peripheral end of each of the leaf valves 5 and 6 can be made extremely large as compared with the amount of expansion of the piezoelectric element 4.
Each damping force generated in 6 can be adjusted in a wider range than the expansion amount of the piezoelectric element 4.

The flow of the pilot when the piston rod 2 moves to the extension side and the compression side, that is, the oil flowing to the extension side first sub-valve 7 and the compression side sub-valve 8 passes through the valve ring after opening and passing these. 71,8
1 through each of the ports 93a and 93b to push and open the extension-side second sub-valve 94 and the compression-side second sub-valve 95,
The fluid flows out to the piston side oil chamber B and the rod side oil chamber A, respectively.

[0042]

According to the present invention, when a voltage is applied to the piezoelectric element, the piezoelectric element expands and contracts in proportion to the voltage, so that the initial bending set load of the extension-side first sub-valve and the compression-side first sub-valve is increased by the voltage. Changes in proportion to As a result, the cracking pressure of each first sub-valve changes, and the pressure in each back pressure chamber can be controlled in proportion to the energizing voltage, so that the damping force can be adjusted in multiple stages at equal intervals, that is, the linear damping force can be adjusted in multiple stages. .

[Brief description of the drawings]

FIG. 1 is a partial longitudinal sectional view showing a damping force adjusting device according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing the vicinity of an extension-side first sub-valve in FIG.

[Explanation of symbols]

 Reference Signs List 1 cylinder, 2 piston rod 4 piezoelectric element 5 extension side damping valve 6 compression side damping valve 5a, 6a back pressure passage 7 extension side first sub valve 8 compression side first sub valve 53, 56 hydraulic chamber 94 extension side second sub valve 95 compression side second Sub valve X Back pressure chamber Y Back pressure chamber

Claims (1)

(57) [Scope of request for utility model registration] 1. A piston rod inserted into a cylinder, a piston body attached to the piston rod and sliding into the cylinder, and one end of an extension port and a compression port opened and closed through the piston body. An expansion-side attenuation valve and a compression-side attenuation valve that are freely disposed; an expansion-side expansion port and a compression-side expansion port provided in the piston body so as to communicate with the expansion-side port and the compression-side port, respectively; A first expansion-side sub-valve and a first compression-side sub-valve disposed in a front-end spigot member attached to a front end for adjusting a flow of hydraulic oil flowing from the expansion-side expansion port and the compression-side expansion port; and the expansion-side expansion port. And the compression-side throttle port to the corresponding rear side of the expansion-side first sub-valve and the compression-side first sub-valve. A back pressure chamber of the extension side damping valve and the compression side damping valve provided so as to communicate with the oil passage;
A piezoelectric element provided in the piston rod so as to face the extension-side first sub-valve and the compression-side first sub-valve, wherein the extension-side first sub-valve and the compression-side first sub-valve are set by electrostriction of the piezoelectric element. A damping force adjusting device for adjusting a damping force by changing a pressure in each of the back pressure chambers by changing a load in proportion to a conduction voltage.