JPS63110977A - Electrostrictive motor - Google Patents

Abstract

PURPOSE:To make a drive voltage small and conserve energy by forming an electrostrictive element for obtaining a driving force into a laminated structure and by applying a drive voltage to each layer. CONSTITUTION:An electrostrictive element 31 of electrostrictive motor is composed of two layers of stratified electrostrictive elements 31a, 31b. Also, a common electrode 32 is positioned midway between both stratified elements 31a, 31b and separate electrodes 33 are formed by adhesion on surfaces of said stratified elements so that their positions respectively coincide with each other. Further, both stratified electrostrictive elements 31a, 31b are bonded to an elastic body 12 to form an oscillator 10. In case of electrostrictive motor driven by traveling wave, sine and cosine waves are respectively given between the common electrode 32 and alternate separate electrodes 33; and in case of said motor driven by standing wave, a frequency voltage with single phase is given between the common electrode 32 and given separate electrode 33. In this manner, a thickness of each of both electrostrictive elements 31a, 31b is 1/2 of that of said element composed of one layer of such element and a driving force thereof can be reduced to 1/2.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to an electrostrictive motor, and particularly to improvements in its electrostrictive element.

"Prior art and its problems" Motors using electrostrictive elements have been devised in various ways. Those that obtain motion (linear motor) or rotational motion are disclosed in Japanese Patent Application Laid-Open No. 58-148.
It was first proposed in issue 682.

First, this electrostrictive motor will be explained with reference to FIGS. 3 to 6. This example shows a configuration example in which an electrostrictive motor is applied to a rotary motor. An annular elastic body 12 is formed. Elastic body 12
is made of a metal material such as A1 alloy or stainless steel, and its upper surface is formed into a sawtooth shape in order to magnify the traveling wave caused by the electrostrictive element 11.

On this vibrator 10, an electrostrictive element 11 and an elastic body 12 are provided.
A rotor (mover) 20 coaxial with is located. This rotor 20 has its shaft 21 inserted into the bearing 13 of the vibrator 10, and its lower end surface is brought into contact with the interface (upper end surface) 14 of the elastic body 12. The rotor 20 is rotated by a traveling wave generated at the interface 14 by a frequency voltage applied to the electrostrictive element 11.

For example, as shown in FIG. 5, the electrostrictive element 11 has a circumferential direction,
That is, polarization processing is performed in a sequence of +, +, -1- in the rotational direction of the rotor 2o. As shown in FIG. 6, this polarization treatment involves attaching a common electrode 15 to one of the front and back sides in the thickness direction of the electrostrictive element 11, and attaching separate electrodes 16 separated from each other to the other side. This is done using the following electrodes.

+ indicates a polarity in which it contracts when a frequency voltage of 10 is applied and expands when a - voltage is applied; conversely, - indicates a polarity in which it expands when a frequency voltage of 10 is applied and contracts when a - voltage is applied. .

Then, every other polarized electrode has one of the phases.
80° different frequency voltages, i.e. sine wave and CO
When an S wave is applied, the electrostrictive element 11 expands and contracts,
A traveling wave is generated at the interface [4] of the elastic body 12, and the rotor 20 is rotated by this traveling wave. 22.23 is a sine wave electrical leakage power source and an os wave power source shown for convenience. When the sine wave and the COS wave applied to the 0-polarized electrode are reversed, the rotation direction of the rotor 2o is reversed.

The above is the basic configuration of the electrostrictive motor proposed in Japanese Patent Application Laid-Open No. 58-148682. Although details such as the reason for the generation of traveling waves are left in the same publication, this motor has already been put into practical use.

On the other hand, the applicant has developed an electrostrictive motor that does not rely on traveling waves based on the above electrostrictive motor, and has filed a patent application. FIGS. 7A and 7B show an example of polarization processing for this purpose, and the relationship between the poles to which the frequency voltage is applied by the frequency voltage source 25 and the rotation direction of the rotor 20. This electrostrictive motor is based on the basic principle of polarization processing applied to the electrostrictive element 11, which is to provide specific voltage application poles on the left and right sides of a voltage application pole, with the same polarity and different polarity as the voltage application pole. It can be driven by a single-phase frequency voltage, and the rotor 20 can be driven by a standing wave instead of a traveling wave.
It has the characteristic of being able to drive.

Therefore, when the left and right polarities of the voltage application poles are changed as shown in FIGS. 2A and 2B, the direction of rotation of the rotor 20 indicated by the arrows is reversed. Since the detailed operating principle of this motor is not a concern of the present invention, further explanation will be omitted.

By the way, in the electrostrictive motor as described above, the electrostrictive element 11
The applied voltage to be applied is determined to be a voltage for obtaining the necessary amount of expansion and contraction, and in the above conventional structure, it was not possible to reduce the applied voltage and save energy.

[Object of the Invention] An object of the present invention is to obtain an electrostrictive motor that can apply a low voltage to an electrostrictive element when the thickness of the electrostrictive element is constant.

"Summary of the Invention J The present invention provides an electrostrictive element having a laminated structure. When a voltage is applied to each layered electrostrictive element, the electrostrictive element having the same thickness as a whole undergoes the same expansion and contraction. This invention was completed by paying attention to the fact that the voltage can be reduced.In other words, the present invention is based on the electrostrictive motor described above, in which the electrostrictive elements that are inserted into the elastic body are composed of a plurality of electrostrictive elements laminated in the thickness direction. It is characterized by having a laminated structure consisting of layered electrostrictive elements, and applying a frequency voltage between the layered electrostrictive elements.

"Embodiments of the Invention" The present invention will be described below with reference to illustrated embodiments. FIG. 1 shows the simplest embodiment of the laminated structure of the electrostrictive element according to the present invention.
The electrostrictive element 31 is composed of two layered electrostrictive elements 31a and 31b. A common electrode 32 is placed between both layered elements, and on the surfaces of both layered elements 31a and 31b,
The common electrode 32F3 and the separated electrode 3 have separate electrodes 33 attached thereto at different positions.
3, layered electrostrictive elements 31a and 31b made of silver paste, for example, are subjected to a predetermined polarization treatment using the common electrode 32 and separation electrode 33, and are coupled to the elastic body 12. The result is a vibrator 10. In the case of the electrostrictive motor using traveling waves, a sine wave and a COS wave are applied between the common electrode 32 and every other separated electrode 33, and in the case of an electrostrictive motor using standing waves, , a single-phase frequency voltage is applied between the common electrode 32 and a predetermined separated electrode 33.

Comparing the above embodiment with the conventional case in which the two layered electrostrictive elements 31a and 31b are composed of a single layer and a driving voltage is applied between the front and back sides, the thickness of the layered electrostrictive elements 31a and 31b is as follows. - It is 172 when composed of layers,
It can be seen that since a particular driving voltage is applied to each of them, the driving voltage can also be reduced to 1/2.

FIG. 2 shows an embodiment in which the electrostrictive element 31 is composed of three layers. In this embodiment, a common electrode 32 is provided between the layered electrostrictive element 31a of the -th layer and the same element 31b of the second layer, and on the surface (lower surface) of the layered electrostrictive element 31c of the third layer. The surface (upper surface) of the layered electrostrictive element 31a of the layer and the same element 31b of the second layer
A separation electrode 33 is provided between the same element 31c of the third layer and the same position M.

In this embodiment as well, the common electrode 32 and the separation electrode 33 are used to form the electrostrictive elements 31 (layered electrostrictive elements 31a to 3]C).
is subjected to a predetermined polarization treatment and bonded to the elastic body 12 to obtain the vibrator 10. and a common electrode 32 and a separate electrode 33
In between, if the predetermined frequency voltage is applied depending on whether the electrostrictive motor is a traveling wave electrostrictive motor or a standing wave electrostrictive motor, rotation can be given to the rotor 2o.

In the case of this embodiment, since the thickness of the layered electrostrictive elements 31a to 31c is 173 mm compared to the case where the electrostrictive element 31 is constructed from the negative layer, the driving voltage can also be reduced to 1/3. The greater the number of laminated layers, the smaller the applied voltage will be, but the number of laminated layers may be determined by taking into consideration manufacturing cost and reduction in applied voltage.

Note that the present invention can of course be applied to a near motor in which the electrostrictive element 31 is deployed linearly, and in this case, the mover is a linear mover.

"Effects of the Invention" As described above, in the electrostrictive motor of the present invention, the electrostrictive element for obtaining the driving force has a laminated structure, and a driving voltage is applied to each layer. Compared to applying a driving voltage to an electrostrictive element, the driving voltage is reduced,
Energy saving can be achieved.

[Brief explanation of the drawing]

1 and 2 respectively show examples of the laminated structure and electrode arrangement of the electrostrictive element used in the electrostrictive motor of the present invention, and FIG. 6 (corresponding sectional view), and FIG. FIG. 4 is a sectional view showing an example of the mechanical configuration of an electrostrictive motor.
5 is a plan view showing an example of the polarization treatment for the electrostrictive element and the frequency voltage applied thereto; FIG. 6 is a schematic sectional view taken along the Vl-Vl line in FIG. 5; Figure 7 (A
) and (B) are plan views showing examples of polarization processing in another electrostrictive motor and frequency voltages applied thereto. DESCRIPTION OF SYMBOLS 10... Vibrator, 11... Electrostrictive element, 12... Elastic body, 14... Interface, 22.23.25... Frequency power supply, 31-... Electrostrictive element, 31a, 31b , 31C...
- Layered electrostrictive element, 32... common electrode, 33-... separation electrode. Patent Applicant Alps Electric Co., Ltd. Agent Kunio Miura Shigeru Matsui Figure 1 Figure 3 Figure 5 Figure 6 (A) (B) Figure 7 Procedure Neho Sho 11 (Voluntary) March 1988 Patent Application No. 256386, dated April 4, 1986 2) Name of the invention Electrostrictive motor 3, Relationship with the person making the amendment Patent applicant address 1-7 Yukitani Otsuka-cho, Ota-ku, Tokyo Name (AO
9) Alps Electric Co., Ltd. Representative Kataoka Kataoka 4, Agent address: 501 Yonbancho Heights, 3-10 Yonbancho, Chiyoda-ku, Tokyo 102 Telephone: 03 (234) 0290
Name (8328) Patent Attorney Kunio Miura (1 other person) 5, Subject of amendment 6, Contents of amendment (1) The scope of claims in the specification will be amended as shown in the attached sheet. (2) On page 6, line 9 of the same book, after "deira.", insert "This laminated structure is a circular electrode-shaped laminated structure in a so-called laminated capacitor." After the above corrections. A document stating the scope of patent claims (Patent Application 1986-
No. 256386) (1) A vibrator having an electrostrictive element bonded to an elastic body, and a movable element that contacts the interface of the elastic body of the vibrator, and the electrostrictive element has a predetermined frequency between its front and back sides. In an electrostrictive motor that is polarized so as to give a moving force to the moving element through waves generated at the interface due to expansion and contraction when a voltage is applied, a voltage of a predetermined frequency is applied between the elements. An electrostrictive motor characterized by: (2) An electrostrictive motor according to claim 1, wherein the electrostrictive element is polarized in an annular manner, and the mover is a rotor. In the first range, the electrostrictive motor is polarized in a linear manner and the mover is an end wire mover.

Claims (3)

[Claims] (1) A vibrator having an electrostrictive element bonded to an elastic body,
and a mover in contact with the interface of the elastic body of the vibrator,
The electrostrictive element is used in a so-called electrostrictive motor in which the electrostrictive element is polarized so as to apply a moving force to the moving element through waves generated at the interface due to expansion and contraction when a predetermined frequency voltage is applied between the front and back surfaces of the electrostrictive element. An electrostrictive motor is characterized in that it has a laminated structure in the form of a circular electrode in the form of a laminated capacitor, and that a predetermined frequency voltage is applied between the layered electrostrictive elements. (2) An electrostrictive motor according to claim 1, wherein the electrostrictive element is polarized in a ring shape, and the mover is a rotor. (3) An electrostrictive motor according to claim 1, wherein the electrostrictive element is polarized in a linear manner, and the moving element is a linear moving element.