JPH04102739A - Damping force adjusting device - Google Patents

Abstract

PURPOSE:To obtain the optimum damping force characteristic and simplify constitution by installing a piezoelectric element, hydraulic chamber and an extension side second subvalve and a compression side second subvalve which set the damping force characteristic corresponding to the speed of a piston rod. CONSTITUTION:An extension side first subvalve 7 and a compression side first subvalve 8 which are arranged in a top edge faucet member 20 installed at the top end of a piston rod 2 and supply the back pressure to the back surfaces of an extension side damping valve 5 and a compression side damping valve 6 and a piezoelectric element 4 which is installed in the piston rod 2 and adjusted each peripheral deflection quantity of the extension side first subvalve 7 and the compression side first subvalve 8 by the magnetostrictive of itself are provided. Inside the top edge faucet member 20, an extension side second subvalve 94 and a compression side second subvalve 95 are connected between the hydraulic chambers 53 and 63 which communicate to the back pressure passages of the damping valves 5 and 6 and a piston side oil chamber B and a rod side oil chamber A, and the damping force characteristic corresponding to the speed of the piston rod 2 is set.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses a piezoelectric element to change the amount of deflection of the peripheral end of a leaf valve as a damping valve, thereby reducing the main damping force generated by the leaf valve. The present invention relates to an improvement in a damping force adjustment device.

[Conventional technology and its issues]

A conventional damping force adjustment device for a hydraulic shock absorber that adjusts the amount of deflection of the peripheral end of a leaf valve, which is a damping valve, by applying voltage to a piezoelectric element, thereby changing the main damping force generated by the leaf valve. However, for example,
It is proposed in No. 149645. This proposal has the disadvantage that the adjustment range of the damping force cannot be made larger than the amount of deformation of the piezoelectric element.

That is, in this proposal, when a voltage is applied to a piezoelectric element, which is an electrostrictive member, and the piezoelectric element expands, the expansion force directly adjusts the amount of deflection of the peripheral end of a leaf valve, which is a damping force valve for generating damping force. , thereby adjusting the level of the damping force generated by the leaf valve.7 Therefore, with this prior art, it is not possible to change the amount of deflection of the peripheral end of the leaf valve beyond the amount of expansion of the piezoelectric element. If a large amount of deflection is required at the peripheral edge of the leaf valve,
Series connection of piezoelectric elements: The mounting amount must be increased significantly, and in this case there is the disadvantage that the axial length of the entire damping force adjustment device increases significantly.

On the other hand, with respect to the cylinder, a growth side leaf valve, which is a damping valve on the growth side, and a compression side leaf valve, which is a compression side damping valve, are respectively disposed on the end face of the screw main body that slides within the cylinder. A back pressure is applied to the back of the orifice through a sub-valve,
Each of these sub-valves is arranged in a tip spigot member connected to the tip of the piston rod, while hydraulic pressure is supplied to the back of each leaf valve, and the expansion force generated in the piezoelectric element is used to control each of the nine sub-valves. The applicant has proposed a device in which the amount of deflection of the circumferential edge is changed to change the oil pressure supplied to the rear surface. However, in the case of such a conventional example, since the above-mentioned orifice is used as a fixed restrictor for a part of the pilot 1, when the screw speed is relatively low (when the amount of oil flowing through the pilot section is relatively small) ), the effect of this throttling is moderate and the hard damping force does not become very high (the back pressure of each leaf valve does not become very high), but as the piston speed decreases -L, the pilot flow rate also increases. , this throttling effect increases and the hard damping force increases accordingly (the back pressure of each leaf valve increases significantly).For this reason, especially on the pressure side, the oil in the piston side oil chamber is sufficiently transferred to the piston rod side oil chamber. This results in so-called oil suction failure. On the other hand, if you try to reduce the throttle effect by increasing the orifice diameter to prevent this, you will not be able to secure the damping range in the low speed range.In other words, the damping force of the hardware will not increase. In addition, the number of parts in the pilot system increased, resulting in disadvantages in terms of ease of assembly and cost.

This invention was made in view of the above-mentioned circumstances, and its purpose is to increase the amount of peripheral deflection of a leaf valve, which is a damping valve, compared to the amount of expansion of a piezoelectric element, which is an electrostrictive member. This increases the adjustment range of the generated damping force, making it optimal for use in hydraulic shock absorbers, and also achieves the optimal damping force characteristics corresponding to the speed of the piston rod, eliminating insufficient oil suction. Another object of the present invention is to propose a damping force adjusting device that can further simplify the configuration.

(Means for Solving the Problems) A damping force adjusting device according to the present invention includes a piston rod inserted into a cylinder, and a piston main body attached to the piston rod that slides in the cylinder. a rebound damping valve and a compression damping valve arranged;
A first rebound-side sub-valve and a first compression-side sub-valve that are disposed within a tip inlet member attached to the tip of the piston rod and supply back pressure to the rear surfaces of the rebound-side damping valve and the compression-side damping valve. , a piezoelectric element that is provided in the piston rod and adjusts the amount of peripheral deflection of the first expansion-side sub-valve and the first compression-side sub-valve by its own magnetostrictive action; A second extension sub-valve and a second pressure sub-valve are connected between the hydraulic chamber communicating with the back pressure passage of each of the damping valves and the screw I-in side oil chamber and the rod side oil chamber, respectively, The damping force characteristics are set in accordance with the speed of the screw rod.[Operation] When the piston rod of this invention slides within the cylinder, hydraulic oil flows from the so-called upstream oil chamber. This extends to the back side of each leaf valve that generates the main damping force via each first sub-valve, and also extends to the pressure-receiving trouble of each leaf valve. By passing, predetermined damping forces are generated on each side. At this time, when a predetermined voltage is applied to the piezoelectric element, the amount of deflection of each peripheral end of each sub-valve is adjusted according to the magnitude of the applied voltage, and the back pressure in each leaf valve is adjusted. Accordingly, the amount of peripheral end deflection of each leaf valve is adjusted, and each damping force generated in each leaf valve is adjusted. As a result, the damping force generated by each of the leaf valves can be changed within a range greater than the amount of expansion of the piezoelectric element.

Moreover, when the application of voltage to the piezoelectric element is released, each first
The amount of deflection at the peripheral end of the sub-valve has returned to its old state.

As a result, the hydraulic pressure acting on the back surface of each leaf valve is also restored to its old state, and the damping force generated by each leaf valve is returned to the initially set magnitude. On the other hand, each second sub-valve is P-
Since the Q characteristic is a 2/3 power characteristic, the above-mentioned back pressure is made relatively high in the low speed range of the piston rod to obtain a sufficient reduction range, and the oil pressure is maintained without excessive back pressure in the medium and high speed range. to prevent poor suction.

〔Example〕

Hereinafter, the present invention will be described in detail based on the illustrated embodiments.

In a hydraulic shock absorber according to an embodiment of the present invention, a piston rod 2 is inserted into a cylinder 1 so as to be freely retractable. It has a piston portion 3 that defines a rod-side oil chamber A and a piston-side oil chamber B therein. In the hydraulic shock absorber, a piezoelectric element 4, which is an electrostrictive member, is disposed in a through hole 2a formed in the axial center of the piston rod 2. A lead wire (not shown) is connected to this piezoelectric element 4, and the end of this lead wire is connected to the piston rod 2.
It protrudes outward from the rear end, which is the upper end of the. The piezoelectric element 4 expands when a predetermined voltage is applied thereto, and the expansion force changes and adjusts the main damping forces on the expansion side and compression side, respectively.

Note that the above expansion force acts so that only the tip of the piezoelectric element 4 moves downward. The piston rod 2 has a distal end spigot member 20 connected to its distal end portion 2b, and a piston portion 3 is interposed on the outer periphery of the distal end spigot member 2o. The piston part 3 has a piston main body 30 that slides within the cylinder 1, and has a growth side leaf valve 5 and a compression side leaf valve 6 arranged so as to sandwich the piston main body 30. The expansion side leaf valve 5 is arranged to close the lower end opening of the expansion side boat 30a opened in the piston main body 30, and the compression side leaf valve 6 is arranged to close the lower end opening of the expansion side boat 30a opened in the piston main body 30. It is arranged so as to close the upper end opening of 30b.

Each of the leaf valves 5 and 6 is an annular leaf valve, and is fixed in a manner that the inner peripheral end is fixed and the outer peripheral end is free, and when each outer peripheral end is bent, the main expansion side and Generates each damping force on the compression side. That is, each of the leaf valves 5 and 6 has its inner peripheral end connected to the piston body 3.
The piston main body 30 is sandwiched between the upper and lower end surfaces of the inner peripheral side of the piston 0 and the step portion 30g of the spacer 50 and the tip spigot member, which are arranged to face the upper and lower end surfaces. The upper and lower end surfaces on the outer circumferential side are adjacent to valve stoppers 51 and 61 disposed so as to face the upper and lower end surfaces. Then, the valve stoppers 51 and 61 press the outer peripheral ends of the respective leaf valves 5 and 6 against the upper and lower end surfaces of the outer peripheral side of the piston body 3o by the urging force from the urging springs 52 and 62, respectively, and the urging force and each leaf valve 5,6
The magnitude of the main damping force generated by each leaf valve 5, 6 is set by selecting the deflection rigidity. Further, in this embodiment, hydraulic chambers 53, 63 are formed on the back side of each leaf valve 5, 6, and these are separated by spacers 50, 63. It is defined by the tip spigot member 20, a valve stopper 51.61, and a housing 54.64 in which the valve stopper 51.61 is accommodated.

Each of the hydraulic chambers 53, 63 communicates with the inside of the tip spigot member 20 through the communication hole 50a bored in the spacer 50°60 and the communication holes 21b and 21c of the tip spigot member 20, respectively. . The tip spigot member 20 has a back pressure passage 5a on the back side of each leaf valve 5, 6 inside.

6a and the first extension side that supplies hydraulic pressure to each hydraulic chamber 53.63.
It has a sub-valve 7 and a first pressure-side sub-valve 8.

That is, the tip spigot member 2.0 has a 7-piece structure consisting of a part 21 of the tip 1 which is the lower end side, a connecting part 22 which is connected to the rod part 2] and the connecting part 22 which is the end side. Each sub-valve 7.8 is housed in a cylindrical inner cavity 21a formed inside the rod portion 21. The amount of deflection of each subvalve 7.8 at its circumferential end is changed by the expansion force generated in the electrostrictive material 4. In this embodiment, each subvalve is an annular leaf valve, and its outer circumferential end is deflected. In some cases, it is set to allow the flow of hydraulic oil through the sub-valve 7 and f3. That is, the first expansion-side sub-valve 7 has an annular seat portion 7 of the valve seat 7 on its back surface.
], a is brought into contact.

The valve seat 1-71 is attached to a valve ring 71b fitted within the inner cavity 21a. j3, the above-mentioned annular seat part 7]-a is the extension side first sub-valve 7
It is located near the inner edge of the back of the Also, the first extension side
The sub-valve 7 has an inner fixed part 72a at the lower part of the valve spool 72 and an outer seat part 7 on its upper pressure receiving surface.
2b are brought into contact with each other. This valve spool 72 is
It is fitted into the inner cavity 21a so as to be slidable in the vertical direction, and has an annular groove 72c between the inner circumferential side fixing part 72a and the outer circumferential side fixing part 721]. Further, a bow h72d passing through the thick upper part of the valve spool 72 is opened in the annular groove 72c. Therefore, in this embodiment, the first extension side in Z
The subvalve 7 has its inner peripheral end sandwiched between the inner peripheral fixing part 72a of the valve spool 72 and the annular seat part 71a of the valve seat 1-71, and its outer peripheral end is fixed in a flexible position. become. Therefore, when hydraulic pressure acts on the outer peripheral end of the first sub-valve 7 on the expansion side, this bends downward in the figure, and in this case, 1. 2. A predetermined flow rate of hydraulic oil is ensured. However, since the inner peripheral end side of the growth side first sub-valve 7 is sandwiched between the innermost inner peripheral side fixing part 72a and the annular sea 1 part 71a slightly closer to the outer periphery, the growth side first sub-valve The inner peripheral end of 7 is an annular sea 1 part 71
-a as a fulcrum and is actively pressed against the inner fixing portion 72a, the outer circumferential end of the first extension-side sub-valve 7 is pressed against the outer circumferential seam 1'/portion 72b of the valve spool 72 by a so-called lever movement, and The amount of deflection of the outer peripheral end of the first sub-valve 7 on the side is changed, and the flow rate of the hydraulic oil through the outer peripheral end of the first sub-valve 7 on the extension side is changed to decrease.

On the other hand, the pressure-side first sub-valve 8 has an annular seat portion 81a of the valve seat 1-81 in contact with the back surface of the pressure side first sub-valve 8. This valve seat 8]- is attached to a valve ring 81b fitted into the inner cavity 21a. Note that the annular seam 1 part 8]-a is brought into contact with the inner circumferential end of the back surface of the pressure side section 1-sub-valve 8. Also,
In the pressure-side first sub-valve 8, an inner peripheral side fixing part 82a and an outer peripheral side seat part 82b at the upper end of the valve spool 72 are brought into contact with a pressure receiving surface which is a lower surface. The valve spool 72 has an annular groove 82c between the inner circumferential fixing part 82a and the outer circumferential seat part 82b. Bow 1-
82 d is opened. Therefore, in this embodiment, the pressure side section 1-subvalve 8 is connected to the inner circumferential end side or the inner circumferential side fixing part 82a of the valve spool 72 and the valve seat 1-8.
] - is held between the annular sea 1 part 8J, a, and its outer peripheral end is fixed so as to be flexible. Therefore, when hydraulic pressure acts on the outer circumferential end of the pressure side first subvalve 8, this bends upward, and at this time, a predetermined flow rate of the hydraulic oil is ensured. And, the pressure side box] - The inner peripheral end side of the sub-valve 8 includes the innermost inner peripheral side fixing part 82a and the annular seat part 8 slightly closer to the outer peripheral side.
1a, so when the inner circumferential end of the pressure side first sub-valve 8 is positively pressed against the inner circumferential side fixed part 82a using the annular seat part 81a as a fulcrum, the outer circumference of the pressure side first sub-valve 8 The end is pressed against a portion 82b of the outer peripheral side seam 1 of the valve spool 72 by a so-called lever movement, and the deflection amount of the outer peripheral end of the first pressure side sub-valve 8 is changed. Therefore, the flow rate of hydraulic oil through the outer circumferential end of sub-valve 8 is adjusted to decrease by 1%. By the way, the hydraulic oil flowing out to the respective downstream side through each sub-valve 7.8 is , a communication hole 211) drilled in the rod portion 21 and a communication hole 5 provided in the spacer 50, respectively.
0a and the communication hole 21c, respectively, to the hydraulic chamber 53.
．． 63. Further, hydraulic oil flows into the upstream side of each sub-valve 7.8 through the expansion side port 30a and the compression side port 30b, which are open to the piston body 30. That is, in the piston body 30,
The extension side sub-port 30c is opened from the inner peripheral surface near the lower end of this piston body 30 to the lower end surface, and the compression side sub-port 3od is opened from the inner peripheral surface near the upper end of the piston main body 30 to the upper end surface of this piston main body 30. ing.

Each of the sub-ports 30c and 30d communicates with the communication holes 21d and 21e formed in the adjacent rod part 21 through the inner peripheral surface of the piston body 30, and communicates with the rod part 21 through these communication holes 21d and 21e. It communicates with the inner cavity 21a of. In addition, each of the two sub-ports 30c and 30d is
Annular grooves 30e and 30f formed in the upper and lower end surfaces of the piston body 30 communicate with the ports 30a and 30b, respectively.

Further, a steel ball 43 is disposed via a slide rod 1o between the valve seat 81 and the block 42 that is locked to the end of the piezoelectric element 4.
Under the alignment structure, when a predetermined voltage is applied to the piezoelectric element 4, an 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.
The housing 54, which supports the biasing spring 52 between the valve stopper 51 and the valve stopper 51, is placed on the flange portion 92a of the valve stopper 51.

Further, the valve rings 71b and 81b have the ports 93a and 93b that pass through them, and each of these ports 93a
, 93b are attached as leaf valves. The port 93a is connected to the expansion side second sub-valve 94 and the plug 9 fitted to the open end of the rod portion 21.
It communicates with the piston side oil chamber B through the through hole 96a of No. 6. Further, the port 93b is connected to the communication hole 99 formed at the pressure side second valve 95° inner space 21a and the base end of the rod portion 21.
It communicates with the rond side oil chamber A via. Further, each of these second sub-valves 94, 95 is ring-shaped, and its inner circumferential end is held by seat members 97, 98 attached to the ends of the valve rings 71b, 81b.

In the hydraulic shock absorber according to this embodiment formed as described above, each port 30a, 30b of the piston body 30
When the hydraulic oil passes through, the hydraulic oil passes through each leaf valve 5.
, 6, while each sub-port 30c
, 30d to the pressure receiving surface side of each sub-valve 7.8.

Further, the hydraulic oil is supplied to the hydraulic chamber 5 formed on the back side of each leaf valve 5, 6 through the sub-valve 7.8 on each side.
3.63, thus suppressing the amount of deflection of the outer peripheral ends of each leaf valve 5, 6. The amount of deflection of the outer peripheral end of each sub-valve 7.8 is controlled by a predetermined voltage applied to the piezoelectric element 4. In this embodiment, the amount of deflection of the outer peripheral end of each sub-valve 7.8 is controlled by applying a voltage to the piezoelectric element 4. If the amount of deflection at the outer end of 8 is changed, until then, each leaf valve 5
．． The amount of oil, that is, the hydraulic pressure, that was being supplied to the back surface of the leaf valves 5 and 6 decreases, and the amount of deflection of the outer circumference of each leaf valve 5 and 6 increases, and the damping force generated in each leaf valve 5 and 6 decreases. It will be adjusted to a downward trend. Each leaf valve 5, 6, which is a damping valve that generates a predetermined damping force during the expansion and contraction operation of the hydraulic shock absorber, has its inner peripheral end deflection amount changed when voltage is applied to the piezoelectric element 4, and the generated damping force is changed. will be adjusted to a higher trend. In this case, when a voltage is applied to the piezoelectric element 4, the expansion force generated in the piezoelectric element 4 is changed by changing the amount of deflection of the outer circumferential end of each sub-valve 7.8, so that the outer circumferential edge of each side sub-valve 7.8 is To limit the flow rate of hydraulic oil passing through, thereby changing the flow rate of hydraulic oil flowing into the rear side of each leaf valve 5, 6, and changing each main damping force generated in each leaf valve 5, 6. become.

As a result, it is possible to make the amount of deflection of the outer peripheral end of each leaf valve 5, 6 extremely large compared to the amount of expansion of the piezoelectric element 4. The amount of expansion of the element 4 can be adjusted over a wide range.

Also, the flow of the pylon 1- when the piston rod 2 moves to the expansion side and the compression side, that is, the expansion side node] sub-valve 7'! The oil flowing to the first sub-valve E and the pressure side sub-valve E3 pushes these apart and passes through, and then wraps around the back of the leaf valves 5 and 6 mentioned above and applies back pressure to the valve ring 7. ] b.

81b through each port 93a, 93b,
The sub-valve 94 and the second pressure-side sub-valve 95 are also pushed open, and the oil flows out into the screw latch side oil chamber B and the rod side oil chamber A, respectively. At this time, each leaf valve 5, 6
The back pressure applied to is determined by the characteristics of each second sub-valve 94.95,
That is, since the P-Q characteristic is a 2/3 power characteristic, it is relatively high in the low speed range of the piston rod 2, but not so high in the medium and high speed range. Therefore, when the screw-in rod 2 operates at low speeds, a sufficient damping range is ensured, and when it operates at medium to high speeds, the hard damping force does not increase significantly, so there is no risk of oil suction failure. . Also, each first
The subvalve 7.8 is provided so as to be supported by an integrally formed m-spool, and controls the movement of the piezoelectric element 4.
The signal can be transmitted to each of these first sub-valves 7.8 with high sensitivity, and the configuration can be simplified and costs reduced.

〔Effect of the invention〕

According to inventions 1 and 2, as shown in J- below, a piston rod inserted into a cylinder, and a bislin body attached to the piston rod 1 and sliding within the cylinder. A rebound damping valve and a compression damping valve arranged on the end face, and attached to the tip of the piston rod,
a first rebound sub-valve and a first compression sub-valve that supply back pressure to the rear surfaces of the rebound damping valve and the compression damping valve; , a piezoelectric element that adjusts the amount of peripheral deflection of the first expansion-side sub-valve and the first compression-side sub-valve by its own magnetostrictive action; A 24th valve on the extension side and a 2nd sub-valve on the compression side are connected between the hydraulic chamber communicating with the piston rod and the above-mentioned screw 1-side oil chamber and rod side oil chamber, respectively, to apply a damping force according to the speed of the piston rod. Since the characteristics are configured to be set, it is possible to make the amount of circumferential deflection of each side leaf valve extremely large compared to the expansion of the piezoelectric element, and therefore, each side leaf valve generated by each side leaf valve This has the advantage that the damping force of the piezoelectric element can be adjusted over a wider range than the expansion sound of the piezoelectric element.

In addition, sufficient damping adjustment is ensured even in the low speed range of the piston rod, the hard damping force is not so high as to cause poor oil suction in the medium and high speed ranges, and the structure can be simplified.

[Brief explanation of drawings]

The drawing is a partial vertical sectional view showing a hydraulic shock absorber according to an embodiment of the present invention. ]...Cylinder, 2...Piston rod, 4...
Piezoelectric element, 5... Growth side damping valve, 6... Compression side damping valve 5a, 6a... Back pressure passage, 7... Growth side first sub-valve, 8... Compression side first sub-valve, 53. 56・
...Hydraulic chamber, 94...Second sub valve on extension side, 95...
・Pressure side second sub-valve, A... side oil chamber, B...
- Oil chamber on the screw 1 side.

Claims (1)

[Claims] A piston rod inserted into a cylinder, a rebound damping valve and a compression damping valve attached to the piston rod and disposed on each end face of a piston body that slides within the cylinder, and a tip end of the piston rod. a first rebound sub-valve and a first compression sub-valve that are disposed within a tip pilot member attached to the piston rod and supply back pressure to the rear surfaces of the rebound damping valve and the compression damping valve; , due to its own magnetostrictive action,
a piezoelectric element that adjusts the amount of peripheral deflection of the first expansion-side sub-valve and the first compression-side sub-valve; a hydraulic chamber that is inside the tip spigot member and communicates with the back pressure passage of each damping valve; A damping force adjustment device comprising: a second extension sub-valve and a second compression sub-valve, which are respectively disposed between the chamber and the rod-side oil chamber and set damping force characteristics according to the speed of the piston rod.