JPH0325466Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a directional control valve, and more particularly, to a directional control valve whose valve seat is opened and closed by a piezoelectric actuator.

[Conventional technology]

A directional control valve that utilizes the property of a piezoelectric element to be distorted when energized and opens and closes a valve seat using a valve body provided in a piezoelectric actuator using the piezoelectric element,
This is already known from Japanese Patent Application Laid-open No. 56-76779 and Japanese Utility Model Application No. 61-152872.

However, since the above-mentioned known directional control valve opens and closes the valve seat using a single piezoelectric actuator fixed at one or both ends to the valve body, the sealing force of the valve body is small and the usable flow rate is low. ,
The problem is that the pressure is limited.

In order to solve this problem, it is conceivable to drive the valve body using multiple piezoelectric actuators, but since the performance of the piezoelectric actuators varies, it is difficult to simply increase the number of piezoelectric actuators. Since the acting forces of the piezoelectric actuator interfere and the efficiency of the actuator decreases, a new problem arises in that a sufficient sealing force cannot be exerted.

[The problem that the idea aims to solve]

The problem to be solved by the present invention is to provide a directional control valve that can effectively utilize the acting force of a piezoelectric actuator to close a valve seat with a large force.

[Means to solve the problem]

In order to solve the above problems, the present invention provides a directional control valve in which a valve seat formed in a valve chamber of a valve body is opened and closed by a valve body provided on a piezoelectric actuator whose end portion is fixed to the valve body. A plurality of actuators are arranged hierarchically in the opening and closing direction of the valve seat, and the above-mentioned valve body is provided at the bent end of these actuators, and the displacement amount of these hierarchical piezoelectric actuators is determined from the valve seat side in the closing direction of the valve seat. It is characterized in that the piezoelectric actuator on the valve seat side has a displacement amount that is gradually increased in the opposite direction and is sufficient to close the valve seat.

[Effect]

When a voltage of a predetermined polarity is applied to the piezoelectric actuators, each piezoelectric actuator is distorted in one direction and the valve body closes the valve seat.

In this case, the amount of displacement of the plural piezoelectric actuators arranged hierarchically is increased sequentially from the valve seat side toward the direction opposite to the closing direction of the valve seat, and the amount of displacement of the piezoelectric actuator on the valve seat side is increased from the valve seat side to the direction opposite to the closing direction of the valve seat. Due to the large displacement of the piezoelectric actuator located on the opposite side of the valve seat, a force acting in the direction of closing the valve seat acts on the piezoelectric actuator on the valve seat side due to the large displacement of the piezoelectric actuator located on the opposite side of the valve seat. Moreover, since the displacement of each piezoelectric actuator was gradually increased,
The acting forces of each piezoelectric actuator do not interfere with each other, and the acting forces can be used effectively. Therefore, the valve body is strongly pressed against the valve seat by the sum of the acting forces of the plurality of piezoelectric actuators.

When the voltage applied to the piezoelectric actuator is removed or a voltage of opposite polarity is applied, the actuator and the valve body return to their original states and open the valve seat.

〔Example〕

Figures 1 and 2 show three directional control valves of the present invention.
A first embodiment is shown in which a port valve is used, and a valve body 1 is constructed by integrating body portions 1a and 1b by appropriate means, and a valve seat 2 is formed inside. An inlet port 3 and a discharge port 4 communicating with the valve chamber 2 are opened in the main body members 1a and 1b with their valve seats 3a and 4a facing each other, and the valve chamber 2
An output port 5 is open to the.

Near one ends of piezoelectric actuators 7, 8, 9 of equal length are fitted airtightly and hierarchically into the peripheral walls of the main body members 1a, 1b, and the other ends of these piezoelectric actuators 7, 8, 9 are fitted in a hierarchical manner. A valve body 10, which will be described later, is provided so as to move together with the piezoelectric actuator. piezoelectric actuator 7,
Reference numerals 8 and 9 are of a bimorph type or the like, which are constructed by pasting piezoelectric elements 12a and 12b on both sides of a substrate 11, which expand and contract depending on the polarity of voltage application.
When a voltage with a predetermined polarity is applied, the piezoelectric actuators 7, 8, 9 are distorted in one direction, and when the voltage is removed or a voltage of the opposite polarity is applied, the piezoelectric actuators 7, 8, 9 are distorted in the opposite direction. All have the same polarity.

As shown in FIGS. 1 and 3, the valve body 10 includes a valve member 14 that abuts the valve seats 3a and 4a, and a valve frame made of an elastic material fitted on both sides of the valve member 14 in the longitudinal direction. 15, 16 and the valve frame 15, 1
The valve member 14 is provided with a connecting frame 17 between the valve frames 15 and 16, and reduced diameter portions 15a and 16a formed at the ends of the valve frames 15 and 16 are connected to the valve member 14.
The valve member 14 and the frames 15, 16, 17 are integrated by fitting into the fitting portions 14a, 14a at both ends.

Each of the frames 15, 16, 17 has an insertion hole 18, into which the bent end 11a of the base material 11 of the piezoelectric actuator is inserted with a slight gap, and into which the valve member 14 is inserted. By passing through the through hole 11b of the distorted end 11a inserted into the holes 18, .
8 and 9, the valve body 10 is biased by a return spring 19 contracted within the valve chamber 2 in a direction to open the valve seat 4a.

As shown in FIG. 4, the piezoelectric actuators 7, 8, and 9 are connected in parallel to a power supply together with a resistor 20, and resistors 21, 21, and 22 are connected in series to the circuits of the actuators 8 and 9, respectively. As a result, the piezoelectric actuator 9,
The voltage applied to actuators 8 and 7 is sequentially increased so that the amount of displacement of actuators 9, 8, and 7 becomes larger in order, and the amount of displacement of piezoelectric actuator 9 is made sufficient to close valve seat 4a. .

Reference numerals 24 and 25 in FIG. 4 are diodes and resistors in a circuit provided to promote discharge of the piezoelectric actuator.

Although not shown, the valve seats 3a, 4a
can be formed in a hollow screw member screwed onto the main body members 1a, 1b, and in this case, the stroke of the valve body 10 can be adjusted by moving the screw member back and forth.

In the first embodiment, as shown in FIG. 1, a voltage of a predetermined polarity is applied to the piezoelectric actuators 7, 8, and 9 in a state where the valve body 10 closes the valve seat 3a and opens the valve seat 4a. When the voltage is applied, the piezoelectric actuators 7, 8, and 9 are distorted in the same direction using the fitting portions with the main body members 1a and 1b as fixed portions, so that the valve body 10 opens the valve seat 3a and closes the valve seat 4a.
Pressure fluid from inlet port 3 thus flows out through outlet port 5.

In this case, the resistor 21 is connected in series to the power supply circuit of the piezoelectric actuator 8, and the resistors 21 and 22 are connected in series to the power supply circuit of the piezoelectric actuator 9, so that the voltage applied to the actuators 9, 8, and 7 is increases sequentially, and the amount of displacement also increases sequentially.

For this reason, even if there is some variation in the performance of the piezoelectric actuators, the actuators 8 and 9 have the valve seat 4
Since a force is applied in the direction of closing a, there is no interference between the forces of the actuators provided in multiple stages, and the forces of each actuator can be used effectively. Therefore, since the valve body 10 provided at the bent end 11a of these actuators closes the valve seat 4a with a force greater than the sum of the acting forces of the actuators 7, 8, and 9, the usable range of flow rate and pressure is limited. Can be expanded.

FIG. 5 shows a second embodiment of the present invention, in which the valve body 3
Side walls 32 of main body members 31a, 31b in 1
a, 32b have a wall thickness that gradually increases toward the valve seat 4a, and piezoelectric actuators 33, 34, and 35 are hermetically fitted at each location where the thickness differs. By sequentially increasing the displacement length, the displacement amount is sequentially increased.

Other configurations and operations of the second embodiment include the resistor 2
Since it is the same as the first embodiment except that 1 and 22 are unnecessary, the same reference numerals are given in the drawings and detailed explanation will be omitted.

[Effect of idea]

In this invention, the displacement of the plurality of piezoelectric actuators arranged hierarchically in the opening/closing direction of the valve seat is gradually increased from the valve seat side toward the direction opposite to the closing direction of the valve seat. Since the acting forces do not interfere with each other, the acting forces of multiple actuators installed can be used effectively.The valve body connected to the distorted end of these piezoelectric actuators closes the valve seat with a large acting force, so the piezoelectric It is possible to expand the usage range of flow rate and pressure of a directional control valve using an actuator.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional front view of the first embodiment of the present invention, Fig. 2 is a plan view of the main parts of the same, Fig. 3 is an exploded perspective view of the valve body, and Fig. 4 is the piezoelectric actuator of the first embodiment. FIG. 5 is a longitudinal sectional front view of the second embodiment of the present invention. DESCRIPTION OF SYMBOLS 1, 31... Valve body, 2... Valve chamber, 4a... Valve seat, 7, 8, 9, 33, 34, 35... Piezoelectric actuator, 10... Valve body, 11a... Distorted end.

Claims (1)

[Claims for Utility Model Registration] A directional control valve in which a valve seat formed in a valve chamber of a valve body is opened and closed by a valve body provided on a piezoelectric actuator whose end portion is fixed to the valve body, the piezoelectric actuator comprising: A plurality of piezoelectric actuators are arranged hierarchically in the opening/closing direction of the valve seat, and the above-mentioned valve bodies are provided at the bent ends of these piezoelectric actuators, and the displacement amount of these hierarchical piezoelectric actuators is changed from the valve seat side to the direction opposite to the closing direction of the valve seat. A directional control valve, wherein the piezoelectric actuator on the valve seat side has a displacement amount sufficient to close the valve seat.