JPH0783343A - Thin film laminated piezoelectric valve - Google Patents

Abstract

PURPOSE:To perform driving at low voltage and further to improve accuracy of flow control at a high pressure by parallelly moving an opening area variable member by a thin film laminated piezoelectric actuator element relating to an opening surface of in/out flow ports of liquid, and variably forming an opening area of the opening surface. CONSTITUTION:To one end of a spool 3 for controlling a flow rate of liquid flowing from inlets 5a, 5b toward outlets 6a, 6b, a thin film laminated piezoelectric actuator element (actuator element) 1 is connected through a shaft 2. A spring 4 is connected to the other end of the spool 3. In the actuator element 1, the spool 3 is driven in proportion to input voltage, and the spool 3 is moved to a side of the spring 4 against its energizing force, to variably control an opening area of the inlets 5a, 5b. That is, the opening area is small before driving and increased by the driving.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film laminated piezoelectric valve, and more particularly to a fluid control valve for controlling a flow rate.

[0002]

2. Description of the Related Art Conventionally, in this type of fluid control valve, as shown in FIG. 2, the opening areas of the inlets 15a and 15b are varied by the movement of the spool 14 so that the flow rate of the liquid flowing out from the outlets 16a and 16b can be controlled. Have control. In addition, spool 1
4 is held in the vicinity of the center by a spring 13, and the liquid flows from the inlets 15a, 15b to the outlets 16a, 16b.
It is designed to flow in the direction of the arrow toward.

In this case, by varying the pressure of the liquid from the pipe lines 17 and 18 applied to both ends of the spool 14, the spool 14 is moved and the opening areas of the inlets 15a and 15b are varied.

When the coil 11 is driven by the input current, the shaft of the torque motor 2 swings to the left and right in proportion to the input current, and the opening widths of the outlets of the pipe lines 17 and 18 are changed.

When the opening width of the outlet of the conduit 17 becomes larger, the opening width of the outlet of the conduit 18 becomes smaller and the conduit 18 becomes smaller.
The pressure inside becomes high. As a result, the spool 14 moves to the inlet 15a side as the pressure in the conduit 18 increases, so that the flow rate of the liquid flowing from the inlets 15a, 15b toward the outlets 16a, 16b increases.

When the opening width of the outlet of the conduit 18 is increased, the opening width of the outlet of the conduit 17 is reduced and the pressure in the conduit 17 is increased. As a result, the spool 14 moves to the inlet 15b side as the pressure in the conduit 17 increases, so that the flow rate of the liquid flowing from the inlets 15a, 15b toward the outlets 16a, 16b decreases.

[0007]

In the above-mentioned conventional fluid control valve, it is necessary to construct a spool drive unit including a torque motor and a coil for driving the spool for controlling the flow rate of the liquid. However, there is a drawback that the device becomes large and the device becomes large.

Further, in order to solve the above-mentioned drawbacks, in recent years,
A method of driving a spool of a valve using a piezoelectric element has been proposed. As a technique of this system, the actual development 62
-114279 and the Unexamined-Japanese-Patent No. 1-212
There is a technique disclosed in Japanese Patent No. 25381.

In the case of this system, the spool drive section including the torque motor and the coil is not required, and the piezoelectric element can directly drive the spool, so that the apparatus can be downsized. However, a valve using this type of piezoelectric element has a drawback that the input voltage to the piezoelectric element is high and the input device becomes large.

Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks and to provide a thin film laminated piezoelectric valve which can be driven at a low voltage and can control a flow rate at a high pressure with high accuracy.

[0011]

A thin-film laminated piezoelectric valve according to the present invention comprises an opening area variable member for changing the opening area of the opening surface by moving in parallel with the opening surface of the outflow and outflow port through which liquid flows in and out. A thin-film laminated piezoelectric actuator element for moving the opening area variable member in parallel with the opening surface.

[0012]

An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, a spool 3 for controlling the flow rate of the liquid flowing from the inlets 5a, 5b toward the outlets 6a, 6b
The thin film laminated piezoelectric actuator element 1 is connected to one end of the through the shaft 2, and the spring 4 is connected to the other end.

The thin film laminated piezoelectric actuator element 1 drives the spool 3 in proportion to the input voltage and moves the spool 3 to the spring 4 side against the biasing force of the spring 4. The opening area of the inlets 5a and 5b is changed by the movement of the spool 3.

That is, before driving the thin film laminated piezoelectric actuator element 1, the spool 3 is biased toward the thin film laminated piezoelectric actuator element 1 side by the biasing force of the spring 4. At this time, since the openings of the inlets 5a and 5b are blocked by the spool 3, the opening area is small.

When the thin film laminated piezoelectric actuator element 1 is driven, the spool 3 resists the urging force of the spring 4 and causes the spring 4 to move.
Since the openings move to the side and the openings of the inlets 5a and 5b open, the opening area increases.

Therefore, the opening areas of the inlets 5a and 5b can be changed according to the input voltage to the thin film laminated piezoelectric actuator element 1, and the inlets 5a and 5b to the outlets 6a and 6 can be changed.
It is possible to control the flow rate of the liquid flowing in b.

Since the piezoelectric ceramic layer of the thin film laminated piezoelectric actuator element 1 is thinned and the size of the piezoelectric ceramic layer is smaller than that of the conventional piezoelectric element, the valve can be made smaller than the conventional valve. .

Further, the thin film laminated piezoelectric actuator element 1
Has a characteristic that the driving voltage is lower than that of the conventional piezoelectric actuator element, and therefore can be driven even with a practical voltage of about 100 V, and the size of the input device can be reduced.

Further, since the thin film laminated piezoelectric actuator element 1 has a high response speed with respect to an input and a large generated stress, it is possible to perform ultrafine driving. This makes it possible to apply the thin-film laminated piezoelectric actuator element 1 to a high-pressure and high-precision liquid control valve in the trend of ultra-high pressure and low flow rate of hydraulic devices in recent years. As the thin film laminated piezoelectric actuator element 1, a commercially available one can be used, and therefore the description of the configuration content thereof will be omitted.

In this way, from the inlets 5a and 5b to the outlet 6
By driving the spool 3 for controlling the flow rate of the liquid flowing in the a and 6b by using the laminated piezoelectric actuator element having a thin film, it is possible to drive the spool 3 at a lower voltage than before, and the size and weight of the input device can be reduced. Can be achieved.

Further, the thin film laminated piezoelectric actuator element 1
Since the response speed to input is high and the generated stress is large, ultrafine driving becomes possible and high-pressure and high-precision flow rate control becomes possible.

In the embodiment of the present invention, the opening areas of the inlets 5a and 5b are changed by the movement of the spool 3. However, even if the opening areas of the outlets 6a and 6b are changed, both openings may be changed. The area may be variable and is not limited to this.

[0024]

As described above, according to the present invention, the opening area variable member for changing the opening area of the opening surface of the inflow / outflow port through which the liquid flows in / out is formed on the opening surface of the laminated piezoelectric actuator element having a thin film. By parallel movement, it is possible to drive at a low voltage, and it is possible to achieve highly accurate flow rate control at high voltage.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a conventional example.

[Explanation of symbols]

 1 Thin Film Laminated Piezoelectric Actuator Element 2 Shaft 3 Spool 4 Spring 5a, 5b Inlet 6a, 6b Outlet

Claims (2)

[Claims] 1. An opening area varying member for varying an opening area of the opening surface by moving in parallel with an opening surface of an inflow / outflow port through which liquid flows, and the opening area varying member with respect to the opening surface. A thin film laminated piezoelectric valve having a thin film laminated piezoelectric actuator element that is moved in parallel. 2. A thin film laminated piezoelectric valve having a biasing member for biasing the opening area variable member in a direction opposite to a moving direction of the opening area variable member by the multilayer piezoelectric actuator element.