JPH06121552A - Piezoelectric actuator - Google Patents

Abstract

PURPOSE:To obtain a piezoelectric actuator which allows linear driving at low voltage. CONSTITUTION:Split electrodes 11, 12 are formed oppositely on the surface and the rear of a piezoelectric ceramic plate 10 and an AC voltage is applied between. Longitudinal oscillation and bending oscillation produced in the piezoelectric plate 10 are combined to produce elliptical movement on the end face of the piezoelectric ceramic plate 10. An object is abutted on the end face and relative position is altered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric actuator, and more particularly to a piezoelectric actuator capable of low voltage linear drive.

[0002]

2. Description of the Related Art The use of piezoelectric motors and piezoelectric actuators in various fields is considered, and piezoelectric motors and piezoelectric actuators having various structures for that purpose have been proposed. This is because there is an advantage that it can be driven with a small amount of power and there is no influence of electromagnetic waves. However, in order to obtain a large torque or a large amount of displacement, there are problems that a complicated structure is required and manufacturing becomes difficult.

Further, the driving voltage must be increased,
There is also a problem that the power supply device for that purpose becomes large.

[0004]

SUMMARY OF THE INVENTION The present invention is intended to obtain a piezoelectric actuator having a simple structure and capable of obtaining a relatively large output.

Another object of the present invention is to obtain a piezoelectric actuator which can be driven at a low voltage and can be easily downsized in a power supply circuit to obtain a linear drive (motion), and which is suitable for positioning a precision device.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by causing longitudinal vibration and bending vibration in a piezoelectric ceramic plate and utilizing the elliptic motion generated thereby.

That is, a rectangular piezoelectric ceramic plate, two electrodes formed on one surface thereof, and two electrodes formed on the other surface so as to face the two electrodes,
Each electrode is connected to a driving power supply, and the elliptical motion generated on the end face of the piezoelectric ceramic plate by the longitudinal vibration and the bending vibration generated on the piezoelectric ceramic plate is used to move the relative position to the object contacting the end face. It is characterized by

[0008]

The vertical and horizontal lengths of the piezoelectric ceramic plate are determined so that the resonance frequencies of the longitudinal vibration and the flexural vibration generated in the piezoelectric ceramic plate match, and two electrodes are formed on the surface so as to face each other. A voltage is applied to this electrode by the same power source to generate each vibration mode. The two vibration modes cause an elliptical motion on the end surface of the piezoelectric ceramic plate. It is possible to move the object that abuts on the end face or move the piezoelectric ceramic plate itself.

Further, since the vibration of the piezoelectric ceramic itself is utilized, it is possible to drive at a lower voltage than a piezoelectric motor or a piezoelectric actuator which vibrates an elastic body. By thinning or stacking the piezoelectric ceramic plates, it is possible to drive even a voltage of several volts.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing the shape of a piezoelectric ceramic plate serving as a resonator element used in the present invention. Electrodes 11 and 12 are formed on the position surface of the piezoelectric ceramic plate 10 by applying and baking a conductive material such as silver. In this example, the two electrodes have the same size.

In actual manufacturing, a 19 mm side of a piezoelectric ceramic plate in which an electrode having a structure divided into two in the direction parallel to the 20 mm side is formed on a 19 mm × 20 mm 0.5 mm thick piezoelectric ceramic substrate is shaved. The dimensions are adjusted so that the resonance frequencies of longitudinal vibration and bending vibration match. When b in Fig. 1 is 19 mm,
When a is 13.3 mm, the bending primary resonance frequency is 113.50 kH
z, the vertical primary resonance frequency was 113.20 kHz, and the two resonance frequencies were almost the same.

When b is 14 mm and a is 9.8 m, the bending primary resonance frequency is 154.00 kHz and the longitudinal primary resonance frequency is 153.70 kHz, and the two resonance frequencies are substantially the same. Furthermore, when b is 9 mm and a is 6.3 mm, the bending primary resonance frequency is 241.04 kHz and the longitudinal primary resonance frequency is 241.0.
It became 0 kHz and the two resonance frequencies matched. The sizes of the piezoelectric ceramic plates when the resonance frequencies were the same were 1.43 for b / a.

Wirings as shown in FIG. 2 were formed on the piezoelectric ceramic plates of each size as described above, and the electrodes were connected to the power source. (1) is the electrode on the left side of the table and the electrode on the right side of the back are connected to the + side, and the electrodes on the right side of the table and the left side of the back are connected to the ground side, and (2) is the reverse connection. is there.

A voltage of a predetermined frequency of 20 Vp-p was applied to the electrodes of the piezoelectric ceramic plate thus connected. Then, the number of rotations of the tachometer having a diameter of 9 mm was measured at 8 measurement points shown in FIG. The results are shown in Table 1. In addition,
The-indicates the opposite direction.

[0016]

[Table 1]

As described above, it was confirmed that elliptic motions were generated in the same direction at any points within the range of to the measurement points. However, the rotation direction was reversed in the range of to. When actually used as an actuator, it is necessary to lower or insulate the ends of the electrodes so that the metal does not come into contact with the end faces and the electrodes on the front and back sides are not short-circuited.

[0018]

According to the present invention, it is possible to obtain a piezoelectric actuator which has a small number of parts, is easy to wire, and has a large momentum by a simple structure and connection. It is possible to place a moving object on the portion that causes this movement and move it at a desired speed and a desired distance.

Further, the applied voltage can be lowered, and the power supply circuit, which has been a problem in the past, can be easily downsized.

[Brief description of drawings]

FIG. 1 is a perspective view of a piezoelectric ceramic plate used in the present invention.

FIG. 2 is an explanatory diagram of wiring

FIG. 3 is an explanatory diagram of the measurement method

[Explanation of symbols]

 10: Piezoelectric ceramic plate 11, 12: Electrode

Claims (1)

[Claims] 1. A rectangular piezoelectric ceramic plate, two electrodes formed on one surface thereof, and two electrodes formed on the other surface so as to face the two electrodes, each electrode being a driving power source. A piezoelectric actuator which is connected to the piezoelectric ceramic plate and uses the elliptical motion generated on the end surface of the piezoelectric ceramic plate by the longitudinal vibration and the bending vibration generated on the piezoelectric ceramic plate to move the relative position to the object contacting the end surface. .