JPS61139280A - Electrostrictive motor - Google Patents

Abstract

PURPOSE:To reduce the entire volume of a piezoelectric motor and its controller by containing an electrostrictive element drive circuit for outputting a high frequency signal in a space in a housing. CONSTITUTION:When a high frequency signal is input from an electrostrictive element drive circuit 12 associated in a printed circuit board 11 to vibrate an electrostrictive element 14 secured through a cushion material 13 to the board 11, a lateral traveling wave of circumferential direction is generated on the surface of an elastic unit 15 fixed to the element 14 to rotate a rotary plate contacted under pressure with the unit 15 in a circumferential direction. In this case, since the drive circuit 12 for outputting a high frequency signal is contained in a space in a housing 10, the entire volume of an electrostrictive motor and its controller can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an electrostrictive motor in which an electrostrictive element deforms to generate rotational force when a signal is input.

(Conventional configuration and its problems) In recent years, electrostrictive motors that generate rotational force using surface waves generated on the surface of circular or plate-shaped electrostrictive elements when high-frequency signals are input have been prototyped and researched. The results are published in the literature
No. 148682), however, no mass-produced commercial product has been announced yet, nor has there been any literature disclosing a configuration suitable for mass production. - (Objective of the Invention) An object of the present invention is to provide an electrostrictive motor that is excellent in mass production in terms of performance, quality, price, etc.

(Structure of the Invention) According to the present invention, when a high frequency signal is input from an electrostrictive element drive circuit incorporated in a printed wiring board and the electrostrictive element fixed to the printed wiring board via a cushion material vibrates, the electrostrictive element Transverse traveling waves in the circumferential direction are generated on the surface of the elastic body fixed to the elastic body, and the rotary plate in pressure contact with the elastic body rotates in the circumferential direction. Examples will be described with reference to the drawings.

FIG. 1 shows a cross-sectional view of an electrostrictive motor according to an embodiment of the present invention, in which 10 is a housing of the electrostrictive motor, and 11 is a print provided with a terminal portion 11a, a copper foil portion 11b, an llc and a lid. This printed wiring board 11 has a peripheral edge that is connected to the housing 1.
Fixed to 0. 12 is a rectifier circuit 30 that rectifies AC 1oov input from an external power source via the terminal section 11a; an oscillation circuit 31 that outputs a high frequency signal of several tens of kHz of sinωt; and a high frequency signal output from the oscillation circuit 31. The amplification circuit 32 amplifies the power and applies it between the copper foil part 11b and the copper foil part lid, and outputs a high frequency signal of several tens of kHz of cos ωt that is 90 degrees in color phase different from the high frequency signal output from the oscillation circuit 31. and the oscillation circuit 33.

This electrostrictive element driving circuit 12 includes an amplifier circuit 34 that amplifies the power of a high frequency signal output from an oscillation circuit 33 and applies the amplified signal between the copper foil section 11c and the copper foil section lid. It is incorporated in the center of the lower surface of the printed wiring board 11. 13 is glued to the lower peripheral edge of the printed wiring board 11;
The fixed cushioning material 14 made of an elastic member such as felt or sponge has 12 surface electrode portions e + f on its surface, as shown in the electrostrictive element polarization/wiring diagram in FIG.
+ g Hh Hl + J + k p l r r
This electrostrictive element 14 is a ring-shaped electrostrictive element made of lead zirconate titanate or the like, in which rL Hn tO and p are provided separately, and one back electrode part is provided on the back surface.
The surface electrode parts e to j are bonded and fixed in a deformable state to the copper foil part 11c through the jumper wire 14a, and the surface electrode parts p to the surface electrode part p are connected to the copper foil part 11b through the jumper wire 14a. The back electrode portions are respectively connected to the copper foil portion lid via jumper wires 14b, and each front electrode portion e
, f, g, h, i, j, 1. m, n, o.

When a positive signal is input for every p and a negative signal is input to the back electrode section, the front electrode section e+k of the electrostrictive element 14
+ g p m * 1 and 0 contract in the circumferential direction as shown by the arrows, and the surface electrode portions f, 1. h
.

n y J and p extend in the circumferential direction as indicated by the arrows. 15 is an annular elastic body made of metal such as steel or brass and is bonded to the surface of the electrostrictive element 14; 16 is an annular facing portion 17 made of a resin having a large coefficient of friction and excellent wear resistance; 18 is an output shaft with the rotating plate 16 fitted on one end, 19 is an output 4i1
1118 is a ball bearing whose intermediate portion is rotatably supported with respect to the housing 10, 20 is a retaining ring fitted to the output shaft 18, and 21 is a compression coil spring interposed between the ball bearing 19 and the retaining ring 20. The output shaft 18 is urged upward in the drawing by the tension of the compression coil spring 21, and the facing portion 17 of the rotary plate 16 is pressed against the elastic body 15. 22 is a bottom plate fitted to the bottom of the housing 10, and this bottom plate 2
2 prevents foreign matter from entering the inside of the casing 10.

In this embodiment configured in this way, a high frequency signal is applied between the terminal itb and the terminal lid, and the high frequency signal is applied between the terminal itb and the terminal lid.
When a high frequency signal having a color phase shift of 90 degrees from this high frequency signal is applied between C and terminal ttd, the electrostrictive element 14 vibrates in the circumferential direction, and the elastic body 15 integrally bonded to the electrostrictive element 14 vibrates in the circumferential direction. The lower surface of is displaced in the vertical direction.

Then, three peaks and three valleys are formed on the lower surface of the elastic body 15, and the three peaks and three valleys generate a traveling transverse wave that rotates in the circumferential direction, and presses against the elastic body 15. Since the facing portion 17 is rotated in the circumferential direction while being supported at three points, the rotary plate 16 rotates in the circumferential direction together with the output shaft 18. By the way, the rotational force transmitted from the elastic body 15 to the facing part 17 is determined by the frictional force between the elastic body 15 and the facing part 17, and the frictional force is determined by the friction coefficient between the elastic body 15 and the facing part 17. and the contact pressure between them, that is, the tension force of the compression coil spring 21. Therefore, if the facing portion 17 is formed of a material with a high coefficient of friction with respect to the material of the elastic body 15, then the facing portion 17 If pressed strongly, a considerable rotational force can be output even if a load is applied to the output shaft 18 and braking is applied to one rotation.

Note that the electrostrictive element drive circuit 12 may be configured with an oscillation circuit 31, an amplification circuit 32, an oscillation circuit 33, and an amplification circuit 34 depending on the signal applied to the terminal portion 11a.

The electrostrictive element driving circuit 12 may be configured by an amplifier circuit 32 and an amplifier circuit 34.Although the electrostrictive element driving circuit 12 has been described as an example built into the lower surface of the printed wiring board 11, it is also possible to incorporate a part or all of the electrostrictive element driving circuit 12 into the lower surface of the printed wiring board 11. It may also be incorporated into the upper surface of the printed wiring board 11.

(Effects of the Invention) As explained above, according to the present invention, since the electrostrictive element drive circuit that outputs a high-frequency signal is housed in the space inside the casing, the electrostrictive motor and its control circuit can be connected to each other. This has the advantage that the overall volume is extremely small and the electrostrictive motor is easy to handle. Furthermore, since the electrostrictive motor and its control circuit are integrated, it is easy to match the natural frequency of the electrostrictive element and the output frequency of the electrostrictive element drive circuit in terms of production management. 1. It has the advantage of being able to mass-produce products with stable quality.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an electrostrictive motor in an embodiment of the present invention, and FIG. 2 is a cross-sectional view of an electrostrictive element in an embodiment of the present invention.
The wiring diagram and FIG. 3 are block diagrams of the electrostrictive element drive circuit of this embodiment. 10... Housing, 11... Printed wiring board, 12...
・Electrostrictive element drive circuit, 13... cushion material, [4
...Electrostrictive element, 15...Elastic body. 16 - Rotating plate. Rod Figures 1 and 2 Figure 2

Claims (1)

[Claims] a printed wiring board incorporating an electrostrictive element drive circuit that outputs a high-frequency signal and fixed to a housing; and a printed wiring board fixed to the periphery of the printed wiring board via an annular cushioning material, and the electrostrictive element An annular electrostrictive element that vibrates when a high frequency signal is input from a drive circuit; and a ring-shaped electrostrictive element that is fixed to the surface of the electrostrictive element, and generates a transverse traveling wave in the circumferential direction on the surface as the electrostrictive element vibrates. An electrostrictive motor comprising: an annular elastic body; and a rotary plate that is pressed against the elastic body and rotates by a transverse traveling wave of the elastic body.