JPH0553996B2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to a switching valve mechanism for power steering, shock absorber, or other control valves, and its objectives are to provide a switching valve mechanism that is lightweight, compact, responsive, and inexpensive. The purpose of the present invention is to provide an excellent switching valve mechanism that satisfies the following requirements.

(b) Prior Art It is well known that conventional switching valve mechanisms drive valves via actuators that control the operation of the valves. For example, in the power steering device disclosed in Japanese Patent Application Laid-open No. 55-44013, a motor and a solenoid are used as the switching valve driving source, and the actuator is complicated, large, and likely to be expensive.

Furthermore, the shock absorber disclosed in JP-A No. 55-65741 uses a motor to adjust the orifice.
The mechanism became complicated, and likewise large and expensive.

Furthermore, instead of the above-mentioned actuator, the hydraulic shock absorber actuator of Utility Application No. 189928/1989 (same applicant as the present applicant) uses a shape memory alloy to perform switching by deformation. However, in this case, the responsiveness of the shape memory alloy is difficult, and the places where it can be used are limited.

In order to improve the switching valve mechanism as described above, a bimorph type electrostrictive element made by bonding two piezoelectric plates,
It has been considered to use a laminated electrostrictive element made by laminating multiple piezoelectric plates or a magnetostrictive element that causes dimensional changes due to magnetization as an actuator, but in both cases, the actuator is actuated from outside the valve. Therefore, it has to be that much larger.

(c) Problems to be Solved by the Invention As is clear from the various embodiments described above, the actuator in the switching valve mechanism is essential, and no matter how small the actuator is made, the actuator itself cannot be eliminated. The current situation is that it is not possible.

The present invention uses an electrostrictive element or an electrostrictive resin as the material forming the valve itself, and switches the valve by expanding and contracting the valve itself, and applies a required voltage to the valve itself. The valve is designed to be deformed to open and close the required orifices and passages, regulate the flow rate, etc., and does not require any external additions, except for the lead wire that charges the valve. It's what I lost.

(d) Means for Solving the Problems In order to achieve the above object, the switching valve mechanism of the present invention partitions the electrostrictive element with an insulator, connects each of these partitions to a controller, and controls the switching valve mechanism from the controller. When a voltage is applied, one section of the electrostrictive element contracts and at the same time another adjacent section expands and contracts, so that the electrostrictive element as a whole is controlled to maintain a constant length in the direction of expansion and contraction. It was constructed as follows.

(e) Effect This will be explained with respect to the power steering valve shown in FIG. 1 in the attached drawings. The spool 1 and the housing (or sleeve) 3 are restrained and fixed to each other at both ends of the spool 1.

Spool 1 has electrostrictive elements 2A and 2B as insulator 2C.
are laminated through.

4 is a controller, and when a displacement signal (for example, voltage) is applied to its signal terminal 5, an electrostrictive element control voltage corresponding to the displacement signal is outputted from output terminals 6 and 7.

In this case, in order to move the spool 1 to the right, the controller 4 sends the required voltage so that the electrostrictive element 2B contracts and the electrostrictive element 2A extends. This movement is used to regulate the relationship between the required passages, that is, the pump pressure passage P and the tank passage T.

Therefore, there is no need for an auxiliary mechanism to mechanically actuate the spool 1, and the controller 4 only needs to be placed at an appropriate remote location.Furthermore, the electrostrictive element has good responsiveness, and as a valve mechanism, this It is impossible to desire something smaller than this.

(F) Embodiment In FIG. 2, the electrostrictive elements 2A and 2B in FIG. 1 are replaced with electrostrictive resins 2A' and 2B', and the operation is the same as that shown in FIG. 1, so the explanation will be omitted. .

FIG. 3 shows an electrostrictive element 2 forming the spool 1 using the housing 3 of FIGS. 1 and 2 as a valve sleeve.
Similarly to A and 2B, the valve sleeve 3' is formed of electrostrictive elements 3A and 3B (or electrostrictive resin), and is configured to expand and contract in the opposite direction to that of the electrostrictive elements 2A and 2B on the spool 1 side, respectively. If it is regulated, the displacement can be reduced to 2
It can be doubled.

(G) Effects of the Invention As described above, according to the present invention, the valve itself is formed of an electrostrictive element or an electrostrictive resin, and the desired operation can be obtained by applying voltages in the forward and reverse directions to this. This concept is different from the conventional structure that operates mechanically from the outside.It is compact and lightweight, saves installation space, and is operated by changes in the physical properties of the valve itself. Therefore, it has reliable operation, high reliability, and good response, and has excellent features that are extremely useful compared to conventional valves, and can be used in various valves.

Furthermore, conventionally, when an electrostrictive element suddenly expands, the mass of the electrostrictive element becomes an inertial load, which generates compressive stress inside the element, and when it suddenly contracts, the mass also becomes an inertial load. Therefore, tensile stress is generated inside the element.

Generally, an element is made up of many thin elements laminated (the interface is an electrode), so if a large tensile stress is generated, this will lead to delamination failure. Furthermore, even in the case of an integral type that is not a laminated type, there is a risk that cracks in the layers may occur inside.

However, in the present invention, when a control voltage is applied from the controller, an expansion/contraction operation occurs in which one section of the electrostrictive element contracts and simultaneously another adjacent section expands, so one section suddenly contracts and tensile stress is generated. Even when this happens, other sections work to reduce (assist) the inertial load, so the stress is lower than in the above case.

Therefore, there is an effect that the durability of the element can be increased when the response is the same as described above, and the responsiveness can be increased when the stress is the same.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the main parts of one embodiment of the power steering switching valve, Fig. 2 is a sectional view of the same main parts of another embodiment, and Fig. 3 is the main part of the third embodiment. FIG. 1... Spool, 2A, 2B... Electrostrictive element, 2
C...Insulator, 4...Controller.

Claims (1)

[Claims] 1.In a control valve that controls the operation of power steering, shock absorber, and other equipment, at least one of the spool or the housing is composed of an electrostrictive element, and the electrostrictive element is divided by an insulator, and each of these divisions is controlled by a controller. When a control voltage from the controller is applied, one section of the electrostrictive element contracts and at the same time another adjacent section expands, causing an expansion/contraction operation, and the length of the electrostrictive element as a whole in the expansion/contraction direction. A switching valve mechanism characterized in that it is configured to perform control to maintain a constant state.