JPH0436231Y2 - - Google Patents

Description

[Detailed description of the invention] <Industrial application field> The invention applies a voltage to piezoelectric ceramics,
The present invention relates to a ceramic actuator element that performs three-dimensional movement in any direction.

<Prior Art> There are actuators shown in FIGS. 4 and 5 that apply a voltage to piezoelectric ceramics and apply distortion due to the piezoelectric inverse effect. FIG. 4 shows what is called a bimorph, in which electrodes 2 are formed on both sides of a rectangular ceramic sheet 1, and two ceramic sheets are bonded together. 3 is a power supply, and when a positive electrode is applied to the outer electrode and a negative electrode is applied to the middle electrode via a lead wire 4, the ceramic is displaced in an arcuate shape.
This displacement is utilized for, for example, a switch. FIG. 5 shows what is called a laminated actuator, in which electrodes 20 are formed on both sides (or one side) of a ceramic sheet 10 with a thickness of about 0.1 mm, for example.
For example, 100 of these ceramic sheets are laminated. (The figure shows only a portion of the laminated ceramics). 3 is a power supply, which connects each laminated ceramic sheet 1 via a lead wire 4.
Apply voltage to both sides of 0. As a result, the laminated actuator is displaced in the direction of arrow A. This displacement is used for position control, etc.

<Problems to be Solved by the Invention> However, in the above-mentioned prior art, the direction of movement is only angular or linear displacement in a certain direction, so there is a drawback that the range of use is limited.

<Means for solving the problems> The present invention was made in view of the above problems.
The object of the present invention is to provide a ceramic actuator element in which the other end can move in at least three directions when one end is supported, and its structural features include piezoelectric ceramics formed in a columnar shape. , a center electrode arranged to penetrate the center of the piezoelectric ceramic in the axial direction, and three or more outer electrodes arranged parallel to the center electrode and equally spaced near the outer periphery of the piezoelectric ceramic. A ceramic actuator element characterized by:

<Operation> When one end of the element is supported and a voltage is applied to the center electrode and one of the external electrodes arranged on the outer periphery, the piezoelectric ceramic on the side to which the voltage is applied expands (or compresses), and the other end is displaced. do. If voltage is applied to the center electrode and two adjacent outer electrodes, the center of the two outer electrodes and the center electrode will expand (or compress).
and the other end is displaced.

<Example> FIGS. 2a, 2b, and 2c are explanatory diagrams for explaining the principle of a ceramic actuator element according to the present invention. In FIG. 2a, 30a is a piezoelectric ceramic (e.g.
BaTiO ₃ + binder), and a conductive metal or piezoelectric ceramic is placed in the center of this cylinder 30a.
Semiconductor ceramics obtained by doping with La, Ta, Nb, etc. (e.g. BaTiO ₃ + La + binder)
and conductive ceramics (e.g. BaPbO ₃ ,
An electrode made of (LaSrCoO ₃ , LaSrCrO ₃ , RuO _{3 ,} etc.) is embedded through the cylinder 30a. A,
A', B, and B' are external electrodes provided on the outer periphery of the cylinder 30a, and are formed by vapor deposition, coating, or the like. In the illustrated example, these external electrodes are formed at four locations equally dividing the circumference along the center electrode 31a.

In the ceramic actuator element having the above structure, for example, when a voltage is applied to the center electrode 31a and the outer electrode A (or B) (the voltage application means is omitted), the piezoelectric ceramic between the electrodes expands slightly, as shown in FIG. 2b. Curve to the left as shown. For example, when a voltage is applied to the center electrode 31a and the outer electrode A' (or B') (the voltage application means is omitted), the piezoelectric ceramic between these electrodes expands slightly and recoils to the right as shown in FIG. 2C. Ru. The present invention utilizes such a phenomenon.

Figure 1 shows an embodiment of the present invention, with 30
is a piezoelectric ceramic fired into a cylindrical shape, and a center electrode 31 is embedded through the center of the cylinder 30 in the axial direction, and is equally spaced on the circumference near the outer periphery and parallel to the center electrode 31. Multiple (8 in the figure)
The external electrodes 41 to 48 of the present invention are embedded.

Configure as above and fix one end (omitted in the diagram)
If a voltage is then applied from a power source (not shown) only to the center electrode 31 and, for example, the outer electrode 40a, the piezoelectric ceramic sandwiched between these electrodes will expand (or shorten), and the entire cylinder 30 will become as shown in FIG. 2b or c. The free end is displaced by curving as shown. The direction of this displacement can be continuously changed by connecting the positive (or negative) pole of a power source to the center electrode 31 and sequentially switching the negative (or positive) poles connected to the external electrodes 40a to 40h. Although not shown in the figure, the electrodes to which voltage is applied are configured to be selectable by a switch using a known method, and are selected depending on the direction and magnitude of driving.

FIG. 3 is a sectional view showing an example of manufacturing the ceramic actuator element shown in FIG.
A second container 61 having an extrusion port 60 in the same direction as the extrusion port of the first container is formed in the first container 51 having the piezoelectric ceramic 30 . The electrode 3 is placed in the container 61 of No. 2.
Semiconductor ceramics obtained by doping piezoelectric ceramics with impurities, such as 0.41, are placed in the form of a paste, and these two types of ceramics are extruded at the same speed at the same time to form the shape shown in Figure 1. It was designed to do so.

A ceramic actuator element that performs such a movement is suitable for use in cases where delicate movement is required, such as handling of a single cell in biotechnology.

<Effects of the Invention> As specifically explained above in conjunction with the embodiments, according to the present invention, a piezoelectric ceramic formed in a cylindrical shape, a center electrode disposed passing through the center of the piezoelectric ceramic in the axial direction, , is equipped with three or more external electrodes arranged equally in parallel with the center electrode and near the outer periphery of the piezoelectric ceramic, so one end is fixed and a voltage is applied from the power source to the center electrode and the external electrode. It is possible to realize a ceramic actuator element that displaces the free end in an arbitrary direction by applying a voltage, or displaces in an oscillating manner by sequentially switching the external electrodes.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing one embodiment of the present invention;
The figure is an explanatory diagram showing the principle of the present invention, Figure 3 is a cross-sectional explanatory diagram showing one embodiment of manufacturing the ceramic actuator of the present invention, and Figures 4 and 5 show conventional ceramic actuators. It is an explanatory diagram. 30... Piezoelectric ceramics, 31... Center electrode, 40... External electrode.

Claims (1)

[Scope of utility model registration request] Piezoelectric ceramics 30 formed into a columnar shape,
A center electrode 31 is arranged to penetrate through the center of the piezoelectric ceramic, and three or more outer electrodes 40a to 40n are arranged parallel to the center electrode and equally spaced near the outer periphery of the piezoelectric ceramic. A ceramic actuator element characterized by: