JPH03223580A - Piezoelectric type valve device - Google Patents

Abstract

PURPOSE:To improve sealing property by forming a communicating part between one plate surface side and the other plate surface side of a valve body, and letting the fluid flow through the communicating part when the valve is opened, while applying the fluid pressure to the rear side of the valve body to carry out the self-sealing when the valve is closed. CONSTITUTION:A valve seat 4 is projected from the part of a flowing-out port 3 inside a casing 1, and a communicating part 6 to communicate one plate surface side 11 and the other plate surface side 12 of a plate-form valve body 5 which is contacted to and separated from the valve seat 4 is provided. When a voltage is applied to a piezoelectric element, the valve body 5 is separated from the valve seat 4, and the fluid flows through a flowing-in port 2, the communicating part 6, and a flowing-out port 3 in order. And when the applied voltage is released, the valve body 5 seats on the valve seat 4 to make the valve closing condition, and in such a condition, the fluid pressure from the flowing-in port 2 acts in the direction to press the valve body 5 to the valve seat 4. A self-sealing is carried out in such a way, and a leakage of the fluid from the flowing-out port 3 can be prevented perfectly.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a piezoelectric valve device that is opened and closed by a piezoelectric element, and particularly relates to a piezoelectric valve device whose valve body is plate-shaped.

[Prior Art] This type of piezoelectric valve device is known from Japanese Patent Application Laid-Open No. 62-28585. The configuration of this conventional piezoelectric valve device will be explained with reference to FIG.

In FIG. 3, a casing 1 has an inlet 2 and an outlet 3, and a valve seat 4 projects from the periphery of the inlet 2 on the inner surface of the casing 1. Reference numeral 5 denotes a plate-shaped valve body in which a plate-shaped piezoelectric element is adhered to a diaphragm, and the plate surface of the valve body 5 is in contact with the valve seat portion 4 when the valve is closed when seated; It can be deformed toward and away from the valve so that it can be in a separated state when the valve is open.

In such a piezoelectric valve device, when a voltage is applied to the piezoelectric element, the piezoelectric element deforms as shown by the two-dot chain line in FIG. 3, and enters the valve open state.

When this voltage application is removed, the valve returns to its original shape and becomes closed.

[Problems to be Solved by the Invention] In the conventional piezoelectric valve device described above, when the valve is closed, the inlet 2
The pressure of the fluid is applied in a direction that moves the valve body 5 away from the valve seat portion 4.

For this reason, especially when the fluid pressure is high, there is a problem in that the valve body 5 slightly separates from the valve seat 4 even when the valve is closed, causing fluid to leak out.

Means for Solving Problem C] The piezoelectric valve device of the present invention includes: a casing having a fluid inlet and an outlet; a valve seat protruding from the outer edge of the outlet on the inner surface of the casing; a plate-shaped valve body whose plate surface can move into and out of contact with the valve seat portion, the valve body being made into contact with and away from the valve seat by a plate-shaped piezoelectric element that is deformed by the application of voltage;
It has a communication portion that communicates one plate surface side and the other plate surface side of the plate-shaped valve body within the casing.

[Operation] In the piezoelectric valve device of the present invention, the valve body is deformed by applying a voltage to the piezoelectric element, and the valve device is switched between opening and closing. When the valve is closed, the fluid pressure transmitted from the inlet into the casing is applied to the back surface of the valve body (the surface opposite to the side seated on the valve seat) via the communication part. It will be done. This back pressure causes the valve body to be pressed against the valve seat when the valve is in the closed state, completely preventing fluid from flowing out.

[Example] FIG. 1 is a sectional view of a piezoelectric valve device according to an example, and FIG. 2 is an operational diagram thereof. In FIG. 1.2, the same or equivalent parts as in FIG. 3 are given the same reference numerals.

In this embodiment, a valve seat portion 4 is provided to protrude from a portion of the inner surface of the casing 1 where the outlet port 3 is located. Further, one plate surface side 11 of the plate-shaped valve body 5 that approaches and separates from the valve seat portion 4
A communication portion 6 is provided that communicates between the plate surface side 12 and the other plate surface side 12.

In the piezoelectric valve device having such a configuration, when a voltage is applied to the piezoelectric element, the valve body 5 separates from the valve seat 4 as shown in FIG. 2, and the fluid flows into the inlet 2. The valve is in an open state in which the fluid flows through the communication portion 6 and the outflow port 3 in this order. In this case, it is also possible to control the flow rate of the fluid by adjusting the gap between the valve seat portion 4 and the valve body 5 depending on the magnitude of the applied voltage.

When the voltage application to the piezoelectric element is removed, the valve is in a closed state in which the valve body 5 is seated on the valve seat 4 as shown in FIG. In this state, the fluid pressure from the inflow port 2 acts on the valve body 5 in the direction of pressing the valve body 5 against the valve seat 4, so that leakage of fluid from the outflow port 3 is completely prevented. .

In addition, since there is no need to fix the piezoelectric element structurally, assembly is easy, and since a flat piezoelectric element can be used, it can be manufactured at low cost.

In the above embodiment, the inlet 2 is provided on one plate side 11, but it may be provided so as to open on the other plate side 12, which is the same as the outlet. For example, it may be provided at the location indicated by A in FIG. Even in this case, when the valve is in the closed state, fluid pressure is transmitted to the back side of the valve body 5 through the communication portion 6, and an action to press the valve body 5 against the valve seat portion 4 is performed.

Further, in the above embodiment, the communication part 6 is provided by being bored into the inner surface of the casing l, but as shown in FIG.
The pressure may be transmitted to the back side of the valve body 5.

In all of the above embodiments, the valve is normally closed when no voltage is applied to the piezoelectric element, but it may be a normally open type that is closed only when voltage is applied.

In the present invention, the valve body may be entirely made of a piezoelectric element, or may be one in which a piezoelectric element is laminated by bonding or the like to a diaphragm plate.

When the valve body is made of a piezoelectric element, the part of the piezoelectric element that comes into contact with the valve seat is made of rubber, rubber,
It is preferable to cover the entire surface of the piezoelectric element with a protector such as a synthetic resin, and this is a more preferable embodiment since corrosion resistance and insulation of the piezoelectric element are improved. Furthermore, the piezoelectric material may not be laminated in advance on the contacting portions. Here, the portion in contact with the valve seat refers to a range approximately 1 to 10 mm wider than the outer diameter of the valve seat.

In the present invention, a valve gasket may be arranged between the valve seat and the valve body.

In the present invention, the piezoelectric body constituting the piezoelectric element includes:
Ceramic and organic materials can be used. Any of a unimorph type, a bimorph type, or a laminated type piezoelectric element can be used.

[Effects] As is clear from the above description, the piezoelectric valve device of the present invention has extremely high sealing performance because it is self-sealed by the pressure of the fluid itself in the closed state, and It has the excellent effect of eliminating time leakage.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a piezoelectric valve device according to an embodiment, and FIG. 2 is a schematic cross-sectional view showing the operating state of the piezoelectric valve device. Moreover, FIG. 3 is a schematic cross-sectional view of a valve using a conventional piezoelectric element. FIG. 4 is a sectional view showing another embodiment. DESCRIPTION OF SYMBOLS 1...Casing, 2...Inlet, 3...Outlet, 4...Valve seat, 5...Valve body,
6...Communication section.

Claims (1)

[Claims] A casing having a fluid inlet and an outlet; a valve seat protruding from a peripheral edge of the outlet on the inner surface of the casing; and a plate-shaped valve body whose plate surface can move into and out of contact with the valve seat. A valve body whose contact and separation is made by a plate-shaped piezoelectric element that is deformed by the application of a voltage, and one plate side and the other plate side of the plate-shaped valve body within a casing. A piezoelectric valve device comprising a communicating portion that communicates with the piezoelectric valve device.