JPH0287979A - Piezoelectric rotary actuator - Google Patents

Abstract

PURPOSE:To perform fine angular control based on application voltage by employing a bimorph type actuator where two piezoelectric elements are sticked around a central electrode, i.e., a metal plate, then applying voltage onto the two piezoelectric elements and causing rotary motion of the rotary shaft. CONSTITUTION:Piezoelectric elements Q, D are polarized electrically in reverse direction. Central symbol P represents a resilient metallic board where Q, D, P are sticked to constitute a kind of spiral piezoelectric bimorph actuator. The direction of electrical polarization is set such that the piezoelectric element D elongates and the piezoelectric element Q contracts upon application of voltage between the anode X and cathode X' and the rotary shaft B rotates clockwise. When such principle is employed, rotary direction and angle of the rotary shaft B can be controlled by varying the magnitude and the direction of voltage to be applied between X and X'.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to an actuator for rotational movement using an electrical method.

(b) Conventional technology Common actuators for rotational motion include stepping motors, AC servo motors, and DC servo motors.

(c) Problems to be Solved by the Invention It is necessary to establish a method that has a simple structure and electrically controls rotational motion.

(d) Means for solving the problem This method will be explained as follows based on the drawings. FIG. 2 shows a plan view of this principle. Q and D are piezoelectric elements whose electrical polarization directions are opposite. P in the center is a metal elastic plate, and Q, D, and P are bonded together to form a kind of piezoelectric bimorph actuator, which is shaped like a spiral. If the direction of electric polarization is determined so that when a voltage is applied here with X as an anode and X' as a cathode, piezoelectric element D will expand while Q will contract, rotation axis B will rotate clockwise. If you apply voltage in the opposite direction, it will rotate counterclockwise. Using the above principle, the rotational direction and rotation angle of the rotating shaft B can be controlled by changing the voltage and direction applied between X and X'. Further, in FIG. 2, the number of turns of the spiral is five, but as the number of turns increases, the sensitivity also increases accordingly.

(e) Effects of the invention Unlike ordinary actuators, minute angles can be controlled by applying voltage without having a brush or mechanical mechanism.

Also, by making it spiral, the range of rotation angles can be expanded.

[Brief explanation of the drawing]

FIG. 2 shows a plan view of a rotary actuator using a piezoelectric element. It is assumed that B is a rotating shaft supported by a bearing or the like. A is a fixed end, and A and B are made of insulating material. V is a bimorph type actuator of a spiral piezoelectric element, P is a metal elastic plate, Q and D are piezoelectric elements with different electric polarization directions, and Y and Y' are electrodes attached to Q and D. C
indicates an AC power supply, and a voltage is applied between the X and X' terminals. FIG. 1 shows a front view of an embodiment of this device. A is fixed end,
V is a bimorph actuator with a spiral piezoelectric element;
B is a rotating shaft supported by a bearing L.

Claims (1)

[Claims] Two piezoelectric elements with a metal plate as the center electrode and paste them together to form a bimorph shape. Bend it into a spiral shape. one side Fix one end to the rotating shaft and the other end to the fixed end do. Apply voltage to these two piezoelectric elements In addition, a method of imparting rotational motion to a rotating shaft.