JPS60257776A - Electrostrictive drive element - Google Patents

Abstract

PURPOSE:To obtain an electrostrictive drive element having simple structure and a small power consumption by using the first piezoelectric element which slidably vibrates in thickness in the halves of the entirety, and the second piezoelectric element vibrating in the thicknesswise direction. CONSTITUTION:The first piezoelectic element 3 which forms part of an electrostrictive drive element is polarized reversely in the front and rear halves 3a, 3b of a column at the polarizing axis as reverse rotary forces in the upper and lower halves. The second piezoelectric element 7 vibrating in the thicknesswise direction of the element 3 is provided on one electrode surface of the element 3, and a rotor 13 is rotatably provided oppositely to the other electrode surface. The second piezoelectric element 7 is connected with a stationary base 14. Thus, when an AC signal is applied to the elements 3, 7, the other electrode surface of the element 3 is contacted only when the element 7 is elongated, a rotary force of one direction is transmitted frictionally to rotate the rotor 13.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electrostrictive drive element that can be used as a drive source for rotational motion and utilizes strain produced by applying a voltage to a piezoelectric element.

Conventional configurations and their problems Most conventional drive sources for rotational motion are motors that use electromagnetic force, but they have a complicated structure and consume a lot of power, or are expensive if made smaller and lighter. There were many problems such as the need for a transmission mechanism in addition to the drive source.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned drawbacks of the conventional art, and aims to drive rotational motion by utilizing strain produced by applying a voltage to a piezoelectric element.
It is an object of the present invention to provide an electrostrictive drive element using a power source, which can be manufactured easily and inexpensively using Fi, has low power consumption, and does not require a transmission mechanism.

Structure of the Invention In order to achieve the above object, the electrostrictive drive element of the present invention is constructed such that each half of the whole vibrates through the thickness and the polarization axes are opposite to each other, and the whole as a whole vibrates torsionally.
a piezoelectric element, and a second piezoelectric element fixed to one electrode surface of the first piezoelectric element and vibrating in the thickness direction of the tenth analectonic crystal, the second piezoelectric element being elongated. At times, the other electrode surface of the first piezoelectric element comes into contact with a rotatable rotor.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

First, the misalignment vibration in which a deviation occurs in a plane parallel to the polarization axis will be explained using FIG. 1.

The piezoelectric element 1 is polarized in the left-right direction, and the right ☆i: surface in the figure is polarized as a positive polarity, and the left end surface is polarized as a negative polarity, and the direction is indicated by an arrow P'? t), by this amount (if electrodes 2 are formed on two mutually parallel surfaces perpendicular to the upper axis, and a positive voltage is applied to the upper surface and a negative voltage is applied to the lower surface (indicated by the arrow "-" in the figure), the upper part will move to the left. The lower part shifts to the right.Therefore, the strain acts upward on the left side and downward on the right side (indicated by arrow S in the figure).

Next, the first piezoelectric element forming a part of the electrostrictive drive element of this example will be explained using FIG. 2.

The front half 3a and the rear half 3b of the cylindrical first piezoelectric element 3 are polarized so that their polarization axes are opposite to each other in the left-right direction (in the figure, the polarization direction is indicated by an arrow P), and the polarization axis is perpendicular to the polarization axis. Electrodes 4 are formed on two surfaces parallel to each other, and a positive voltage is applied to the top surface and a negative voltage is applied to the bottom surface (indicated by arrow E in the figure), using the same principle as explained in FIG. On the right side, the image is distorted upward, and on the right side, it is distorted downward. Therefore, a clockwise rotational force acts on the upper half, and a counterclockwise rotational force acts on the lower half. When voltages in opposite directions are applied, rotational forces act in opposite directions. When the voltage is removed, it returns to its original position.

When an AC signal is applied, rotational force is applied alternately in both directions.

Next, thickness vibration will be explained using FIG. 3.

The electrodes 6 formed on both end faces of the piezoelectric element 5 (the polarization direction is indicated by the arrow P), the upper N pole 6 has a positive electrode, and the lower electrode 6
When a negative voltage is applied to , it becomes distorted in the vertical direction (as shown by the arrow S).

Next, a second piezoelectric element that forms a part of the electrostrictive drive rope a5 in one embodiment of the present invention will be explained with reference to FIGS. 4 and 5. The second piezoelectric element 7 has n piezoelectric ropes 7a in order to minimize the amount of strain. FIG. 4 shows the relationship between the polarization direction and the electric field direction in the case of stretching in the thickness direction, and FIG. 5 shows the relationship between the polarization direction and the electric field direction in the case of shrinking in the thickness direction. When the voltage is removed, it returns to its original position (3j).

When an AC signal is applied, it expands and contracts alternately in the thickness direction.

Note that 8 is an electrode.

Next, a second piezoelectric element constituting a part of the electrostrictive driving element in J3 according to another embodiment of the present invention will be described with reference to FIGS. 6 and 7. This second piezoelectric element utilizes flexural vibration by cantilevering a piezoelectric element with a bimorph structure. t, two piezoelectric element plates 9a and 9b
When the polarization directions (indicated by arrow P?1-) are in the same direction, it is called a parallel bimorph. This parallel type biself is supported by supports 10 and 11 to form a cantilever beam. As shown in FIG. 6, when a negative voltage is applied to the intermediate electrode 12 and the support 10.11, the second piezoelectric element plate 9a expands as shown by the arrow S due to the piezoelectric effect. Piezoelectric element plate 9b
On the contrary, it shrinks. As a result, the tip of the second piezoelectric element 9 is displaced downward as shown by the arrow. When a reverse voltage is applied, the tip of the second piezoelectric element 9 is displaced upward in the direction of the arrow, as shown in FIG.

Next, as a second piezoelectric element, an electrostrictive driving element d3 (J) will be explained using FIG. 8 as an embodiment of the present invention that utilizes the thickness vibration of the piezoelectric element. This is a first piezoelectric element that vibrates, and this first piezoelectric confectionery 3
The second piezoelectric element 7, which vibrates in the thickness direction of the electric thread element 3 and explained in FIGS. A rotor 13 is rotatably provided opposite the other electrode surface.Second piezoelectric element 7
is connected to the fixed base 14. When an alternating current signal is applied to the first and second piezoelectric elements 3 and 7 of the electrostrictive drive cord having this configuration, only when the second piezoelectric element 7 extends, the other electrode surface of the first piezoelectric element 3 comes into contact with the rotor 13 and transmits rotational force in one direction to the rotor 13 due to friction. In this way, the rotor 13 rotates.

Next, an electrostrictive drive element according to another embodiment of the present invention in which a second piezoelectric element is used, and a piezoelectric element made of a bimolino type is used as a cantilever beam to utilize flexural vibration will be described with reference to FIG. 3 is the first piezoelectric element that vibrates torsionally as explained in FIG. 2, and the electrodes shown in FIGS. 7, the second piezoelectric element 9 is installed, and the rotor 13 is placed on the other electrode surface of the first piezoelectric element 3; Second piezoelectric element 3.9
When an alternating current signal is applied to the second pressure 7, the element 9
As in the embodiment shown in FIG.
I will tell 3. In this way, the rotor 13 rotates -
Ru.

According to the detailed description of the invention, the present invention has a simple structure, can be manufactured at low cost, and can reduce power consumption, compared to conventional electromagnetic force ()/ζ7-ta. Moreover, a transmission mechanism can be made unnecessary.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of thickness shear vibration, FIG. 2 is an explanatory diagram of the operation of a first piezoelectric element used in an electrostrictive drive element according to an embodiment of the present invention, and FIG. 3 is an explanatory diagram of thickness vibration. 4th and 5th
The figure is an explanatory diagram of the operation of a second piezoelectric element used in an electrostrictive drive element according to an embodiment of the present invention, and FIGS. FIG. 8 is an explanatory diagram of the operation of the second piezoelectric element used, FIG. 8 is an explanatory diagram of the operation of the electrostrictive drive element in one embodiment of the present invention, and FIG. 9 is an explanatory diagram of the operation of the electrostrictive drive element in another embodiment of the present invention. It is an operation explanatory diagram. 3... First piezoelectric element, 4, 8... Electrode, 7, 9...
...Second phosphor element, 10.11...Support, 13.
...Rotor agent Yoshihiro Morimoto Figure 1 Figure 2 Figure 3 Figure O

Claims (1)

[Scope of Claims] 1. A first piezoelectric element configured such that each half of the whole undergoes thickness-shear vibration and whose polarization axes are opposite to each other, and which performs torsional imaging as a rest, and this first piezoelectric element and a second piezoelectric element fixed to one electrode surface of the first piezoelectric element and vibrating in the thickness direction of the first piezoelectric element, and when the second piezoelectric element is expanded, the other electrode surface of the first piezoelectric element An electrostrictive drive element configured such that the element contacts a freely rotatable rotor. 2. The electrostrictive drive element according to claim 1, wherein the second piezoelectric element is configured to utilize flexural vibration by using a bimorph piezoelectric element as a cantilever beam. 3. The electrostrictive drive element according to claim 1, wherein the second piezoelectric element is configured to utilize thickness imaging of the piezoelectric element.