JPS59112527A - Piezoelectric type drive device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piezoelectric drive device using a bonded piezoelectric element that utilizes an electrostrictive phenomenon, and can be used, for example, for opening and closing relays and valves.

In general, voltage type drive devices are (1) smaller, (2) consume less power, and (3) compared to conventional electromagnetic type drive devices.
) It has advantages such as almost no heat generation and (4) low price, but on the other hand, it has the disadvantage that the driving voltage of the piezoelectric element is large (up to several hundred square meters).

The piezoelectric drive device according to the present invention is characterized in that it uses a voltage transformer to boost the voltage. Piezoelectric transformers have advantages over wire-wound transformers, such as being cheaper, smaller, lighter, and safer, but have the disadvantage of low output power. However, although piezoelectric drive devices have a high drive voltage, their power consumption is low, so boosting the voltage using a piezoelectric transformer is most suitable for piezoelectric drive devices. Therefore, it is an object of the piezoelectric drive device according to the present invention to provide a piezoelectric drive device that is inexpensive, small, lightweight, and highly safe by having the above configuration.

FIG. 1 shows an embodiment of a piezoelectric drive device according to the present invention. Reference numeral 1 is a case made of resin, aluminum, SuS, etc., and reference numeral 2 is a piezoelectric transformer section.

The piezoelectric transformer includes an oscillation circuit section 2-1, a piezoelectric element 2-2, and a rectifier circuit including diodes and capacitors 2-3. The piezoelectric element 2-2 has a pair of electrodes AmA2 in the thickness direction on one half A of the plate-like element, and an electrode B1 on the lengthwise end surface of the other half B, with the former having a pair of electrodes AmA2 in the thickness direction, and the other half B having an electrode B1 on the end face in the length direction. is polarized by applying a DC voltage Ell jJll in the length direction.

Here, part A is called an oscillation part, and part B is called a power generation part, which are equivalent to the primary and secondary sides of a wire-wound transformer, respectively.

Generally, the piezoelectric element 2-2 is made of PzT, and the electrodes are made of Ag.

3 is a piezoelectric drive section using a cantilevered piezoelectric element 5, which is structurally integrated with the piezoelectric transformer section 2 through a case 1. Reference numerals 6 and 7 indicate piping, and the piezoelectric element is provided with a valve seat so that the valve can be opened and closed. 8 and 9 are power input terminals.

10 to 13 are coil type switching for high voltage; switching 10. The configuration is such that t3 and switching 11 and 12 are respectively linked. For example, switching 11.
12 is ON and switching 10.13 is OFF, the piezoelectric element 5 bends in the direction shown by the solid line, so that the pipe 7
is closed, conversely switch 10.13 is ON, switch 1
When 1.12 is OFF, voltage is applied to the opposite side of the piezoelectric element 5, so the piezoelectric element 5 bends in the direction of the broken line and the pipe 6 closes.

Figure 2 shows an example using one switch indicated by 7.
When the switch 7 is ON, no voltage is applied to the piezoelectric element 5, so the pipe 6 is open. When the switch 7 is OFF, voltage is applied to the piezoelectric element 5, so the piezoelectric element 5 moves in the direction of the broken line. After bending, the pipe 6 is closed by a valve seat attached to the piezoelectric element 5.

In addition, the piezoelectric element 5 is used for opening and closing the valve of the pipe 6.7, and also for the following purposes:
It can also be used to operate relay contacts.

The above pressure@transformer is similar to a normal piezoelectric transformer,
The capacitance of the capacitor 2-3 can be several hundred PF, but since the capacitance of the piezoelectric element 5 is large and is about several nF, when a voltage is applied to the piezoelectric element 5, the capacitor 2
-3 and the piezoelectric element 5 cannot be matched, so it takes more than 10 seconds for the piezoelectric element 5 to move. Therefore, in this device, it is desirable that the capacitance of the capacitor 2-3 be set to a value larger than the human power capacitance of the piezoelectric drive unit, preferably several tens of nF, which is ten times or more.

This device integrates a piezoelectric element with a piezoelectric transformer, so
It is simple in structure and allows high voltage to be applied to the piezoelectric element.
This can be activated quickly.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing one embodiment of the present invention, al 2
The figure is an overall configuration diagram showing another embodiment of the present invention. 1...Case, 2...Piezoelectric transformer, 2-1...
Oscillation circuit section, 2-2... piezoelectric element, 2-3... rectifier circuit, 3... piezoelectric drive section, 5... piezoelectric element. Representative Patent Attorney Takashi Okabe

Claims (1)

[Claims] In a drive device for a cantilevered bimorph piezoelectric element, a rectifier circuit that is a piezoelectric transformer and rectifies the output signal of the piezoelectric element, and a capacitor having a capacity sufficiently larger than the capacity of the piezoelectric element that accumulates this rectified output are integrated. 1. A piezoelectric drive device configured integrally with a piezoelectric transformer having a capacitor, and applying a drive voltage to the piezoelectric element from the capacitor.