JPH0336768Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a valve using a laminated piezoelectric element that can be used to control fluid, particularly air pressure.

[Prior Art] Generally, as a pneumatic control valve, a solenoid valve using an electromagnet as an actuator is widely used.
However, in recent years, with the spread of digital circuits and microcomputers, these electronic devices have become smaller and control valves have come to be controlled by these electronic devices, and control valves using piezoelectric elements have been proposed. Compared to electromagnets, using a piezoelectric element as an actuator has advantages such as no noise, no heat generation, no sound, low power consumption, the ability to miniaturize devices that operate quickly, and good proportional controllability. Actuators using piezoelectric elements include a bimorph type and a laminated type in which thin plate piezoelectric elements are laminated and integrated.The former has a displacement of several hundred micrometers, but a generated force of several tens of grams.
When controlling compressed air of several kg/cm ² , the valve diameter must be small enough to operate, and therefore it can only be used for valves with small flow rates. On the other hand, the latter laminated type generates a force of several tens of kilograms, but the amount of displacement is several tens of kilograms.
As small as 10μm. In the latter, a piezoelectric laminate formed by laminating and integrating piezoelectric ceramic plates as thin piezoelectric elements, a hydraulic pump as a displacement magnifying mechanism for magnifying the axial displacement of this piezoelectric laminate due to an applied electric field, and this hydraulic pump. There is a valve including a connected plunger (Japanese Patent Publication No. 60-211176).

[Problems to be solved by the invention] If the displacement magnification mechanism is a hydraulic pump, or a hydraulic type, the minute movement of the large diameter piston is increased and transmitted to the small diameter piston via oil. If the sliding portion of the piston is not reliably sealed, oil leakage may cause unstable operation, and the structure is also complicated.
The present invention was developed in response to this problem, and uses a laminated piezoelectric element, and instead of using a hydraulic type as an expansion mechanism, it is a valve that is simply constructed from a lever lever and a link part, and has a large flow passage cross-sectional area. is intended to provide.

[Means for Solving the Problems] A valve using a piezoelectric element according to the present invention has a tubular valve body 2 slidable in the axial direction within a housing 1, as shown in FIG. The valve chambers 3 and 4 formed at both ends of the valve body have valve seats 5 and 6 at the axial position facing the valve body 2, and when one comes into close contact with the valve body 1, the other valve seat are arranged apart from the valve body 1, respectively. In the central chamber 7 of the housing 1, a fixed end of a piezoelectric laminate 11 is fixed to the housing 1 in parallel with the valve body 2, and there is also an L-shaped lever that engages with the movable part of the piezoelectric laminate to increase displacement. Lever 1
2b is provided on the outside of the piezoelectric laminate 11.
An elastic link member 14 is provided between the driven end of the lever lever 12b and the valve body 2 to change the displacement of the lever into an axial movement of the valve body against the spring 15 biased against the valve body 1. It is constructed by connecting.

[Operation] The operation of the present invention will be explained with reference to FIGS. 1 and 2. First, when the piezoelectric laminate 11 is not energized, the valve body 2 is urged by the spring 15 and presses against the valve seat 6. , the valve seat 6 is closed. On the other hand, the upper valve seat 5 is opened apart from the valve body 2. (Figure 1).

Next, when electricity is applied to the piezoelectric laminate 11, the piezoelectric laminate 11 expands in the direction of application of the electric field, that is, in the axial direction.
Therefore, the L-shaped lever lever 12b that engages with the movable part of the piezoelectric laminate 11 moves around the fulcrum 12c, and the minute displacement of the movable part is magnified at the driven end of the lever lever 12b, as shown in FIG. The displacement is in the direction of the arrow shown in . Due to this displacement, the lever lever 12b
The elastic link member 14 connecting the driven end of the valve body 2 to the valve body 2 moves the valve body 2 upward against the spring 15, and the valve body 2 is separated from the valve seat 6 and pressed against the valve seat 5. Valve seat 6 opens and valve seat 5 closes (Figure 2).

When the electricity is turned off, the piezoelectric laminate 11 returns to its original length and the valve body 2 is pushed down by the spring 15, returning to the state shown in FIG. 1.

[Example] Next, an example of the present invention will be described in detail with reference to the drawings. 1 and 2 are cross-sectional views of a three-way control valve, in which 1 is a thin housing with a rectangular cross section, and a tubular valve body 2 is provided in the center of the housing so as to be slidable in the axial direction. It is being Valve chambers 3 and 4 are formed at both ends of the valve body 2, and valve seats 5 and 6 are provided in each valve chamber coaxially with the valve body 2 and facing the valve body 2. 2 is arranged so that when it is in close contact with one valve seat, it is separated from the other valve seat. In the drawing, the lower valve chamber 6 is imported 4a.
The upper valve chamber 5 communicates with the exhaust port 3a. Further, a through hole having approximately the same diameter as the hollow passage 2a of the valve body 2 is provided in the axial center of the valve seat 5, and an out port 3b communicates with the valve chamber 3.
When the valve body 2 is in close contact with the valve seat 5, the exhaust port 3
Communication between a and the out port 3b is cut off.

A central chamber 7 in the housing 1 through which the valve body 2 penetrates accommodates a piezoelectric laminate serving as an actuator, a displacement magnifying mechanism, and the like. That is, the fixed end of the piezoelectric laminate 11 is fitted and fixed to the L-shaped fixing member 12a in parallel to the outside of the valve body 2, and the fixing member 12a is fixed to the housing 1 by a bolt 16. Fixed. An inverted L-shaped lever lever 12b is integrally provided on the outside of the fixing member 12a and communicates with the fixing member 12a through a thin wall portion 12c. 12c functions as a fulcrum for the lever 12b. The upper movable end of the piezoelectric laminate 11 is fixed by fitting or the like to an engagement connecting portion 12e that is connected to a lever lever 12b through a thin wall portion 12d. A connecting member 13 is fixed to the outer periphery of the valve body, and is provided at a position slightly higher than the driven end of the lever lever 12b. Reference numeral 14 denotes a link member that converts displacement of the lever lever 12b into axial movement of the valve body 2, and includes a link member 13 fixed to the valve body 2 at both ends thereof, and a driven end portion 12 of the lever lever 12b.
f and are connected to each other. Link member 14
A plate-shaped elastic body is used so that the displacement of the lever lever 12b can be smoothly transmitted to the axial movement of the valve body 2. FIG. 3 is a perspective view of the actuator section described above, and shows a configuration in which the width of the components such as the lever lever is approximately the same as the width of the piezoelectric laminate and is arranged on one plane. In this embodiment, the fixing member 12a and the lever lever 12b are integrally molded from an invar material with a small coefficient of thermal expansion or stainless steel, but they may be used in combination with separate members.

In FIG. 1, a spring 15 is provided between a connecting member 13 fixedly attached to the valve body 2 and a fixing member 12a, and is biased to press the valve body 2 against the valve seat 6. 8 and 9 are seal members.

In this embodiment, two sets of actuators are disposed on one plane on both sides of the valve body 2, but only one set may be disposed on one side.

Next, the operation will be explained. In the state shown in FIG. 1 in which the piezoelectric laminate 11 is not energized, the valve body 2
is pressed against the valve seat 6 by the spring 15, and the valve seat 6 is closed, while the upper valve seat 5 is separated from the valve body 2 and opened. Therefore, fluid from the inlet 4a is blocked, and the outport 3b and exhaust port 3a are in communication. When the piezoelectric laminate 11 is energized, the piezoelectric laminate 11 expands in the direction of application of the electric field, that is, in the axial direction. Therefore, the thin wall portion 12d connected to the movable end of the piezoelectric laminate 11 becomes the point of action, the L-shaped lever lever 12b moves around the fulcrum 12c, and the minute displacement of the movable portion is applied to the driven end of the lever lever 12b. At 12f, it is enlarged and displaced in the direction of the arrow shown in FIG. For example, if the dimensional ratio between the point of action and the fulcrum and between the fulcrum and the driven end is set to 1:20, the displacement of the piezoelectric laminate from 50 μm will be expanded to 1000 μm. Due to this displacement, the elastic link member 14 connecting the driven end of the lever lever 12b and the valve body 2 overcomes the biasing force of the spring 15 and pushes the valve body 2 upward, so that the valve body 2 is removed from the valve seat 6. It is pressed against the separate valve seat 5. Therefore, the inlet 4a communicates with the outport 3b via the passage 2a in the valve body 2,
On the other hand, communication between the out port 3b and the exhaust port 3a is cut off, and the flow path is switched to the state shown in FIG. 2. When the current is further turned off, the piezoelectric laminate 11 returns to its original length and the valve body 2 is pushed down by the spring 15, returning to the state shown in FIG.

In the three-way control valve of this embodiment, by moving the tubular valve body, valve seats provided at both ends of the valve body are opened and closed, respectively, to switch the fluid flow direction. A large flow path area is obtained, and the piezoelectric laminate and simple displacement amplification mechanism of a lever lever move the valve body to change the direction of fluid flow, making it usable for large loads such as driving pneumatic cylinders. Ta. In addition, as another example, by blocking the import 4a with a blind plug,
It can be used as a two-way valve, and in addition to ON-OFF control, it can also be used as a flow rate control valve because the amount of displacement can be changed and the cross-sectional area of the flow path can be controlled by changing the voltage applied to the piezoelectric actuator.

Furthermore, if the valve has a built-in drive circuit for converting the amplitude control signal from an external microcomputer into a high voltage control signal that can drive the piezoelectric element, it can be directly controlled by the amplitude control signal from the computer. You can also do it.

[Effects of the invention] As explained above, according to the invention, a simple lever lever and a link are used as the displacement magnification mechanism for the piezoelectric laminate instead of using a hydraulic system, so there is no fear of oil leakage and it is highly reliable. At the same time, the cross-sectional area of the upstream passage of the valve structure can be increased and can be used for direction switching, flow rate control, etc. Furthermore, since the thickness of the valve can be reduced, the degree of valve integration is high and the practical effect is great.

[Brief explanation of the drawing]

FIGS. 1 and 2 are cross-sectional views of an embodiment of the present invention, with FIG. 1 showing a state in which electricity is not applied, and FIG. 2 showing a state in which electricity is applied. FIG. 3 is a perspective view of the main parts of the valve body and actuator. DESCRIPTION OF SYMBOLS 1... Housing, 2... Valve body, 3, 4... Valve chamber, 5, 6... Valve seat, 11... Piezoelectric laminate, 12
b...Lever lever, 14...Link member, 15...
…spring.

Claims (1)

[Claims for Utility Model Registration] <1> Valve chambers 3 and 4 formed at both ends of a tubular valve body 2 slidably provided in the axial direction within the housing 1, facing the valve body. Valve seats 5 and 6 are arranged at the axial center position so that when one valve seat comes into close contact with the valve body 1, the other valve seat is separated from each other, and the valve body 2 and the valve body 2 are arranged in the central chamber 7 of the housing 1. The piezoelectric laminate 11 is fixed to the housing 1 in parallel, and an L-shaped lever lever 12b that engages with the movable part of the piezoelectric laminate to increase displacement is provided on the outside. An elastic link member 1 that changes the displacement into an axial movement of the valve body against a spring 15 biased against the valve body.
A valve using a piezoelectric element, characterized in that a lever lever 12b and a valve body 2 are connected through a lever 4. <2> A valve using a piezoelectric element according to claim 1, in which the support body 12a for fixing the piezoelectric laminate 11 to the housing 1 and the L-shaped lever lever 12b are integrally molded. <3> Using the piezoelectric element according to claims 1 and 2 of the utility model registration claim, in which two sets of the piezoelectric laminate 11 and the displacement magnifying mechanism are respectively disposed on one plane on both sides of the valve body 2. It was a valve.