JPS63110976A - Electrostrictive motor - Google Patents

Abstract

PURPOSE:To improve efficiency with a low voltage by forming an electrostrictive element for obtaining a driving force into a laminated structure and by applying different drive frequency voltages after interposing a common electrode midway between said elements. 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 elements 3la, 31b are bonded to an elastic body 12 to form an oscillator 10. Then, after the electrostrictive element 31 has been formed into a laminated structure, a phase of frequency voltage to be applied thereto is made to differ on the upper and lower sides or the intermediate common electrode 32 to enable generating the same expansion and contraction as before in the electrostrictive element 31, for example, at a low drive voltage of 1/2 as compared with the existing one.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to an electrostrictive motor, and particularly to improvement of an electrostrictive element thereof.

"Prior art and its problems" Various motors using electrostrictive elements have been proposed in the past, but one of them is that it is possible to achieve linear motion by a traveling wave that is a combination of transverse waves and longitudinal waves excited at the interface of an ultrasonic vibrator. (linear motor) or one that obtains rotational motion is
It was first proposed in issue 682.

First, this electrostrictive motor will be explained with reference to FIGS. 2 to 5. This example shows a configuration example in which an electrostrictive motor is applied to a rotary motor. An annular elastic body 12 is formed. The elastic body 12 is made of a metal material such as an At 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 1o, 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. [Electrostrictive Element] This is a configuration in which the rotor 20 is rotated by a traveling wave generated at the interface 14 by a frequency voltage applied to the electrostrictive element 1.

For example, as shown in FIG. 4, 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 20. As shown in FIG. 5, this polarization treatment involves attaching a common electrode 15 to either the front or back side of the electrostrictive element 11 in the thickness direction, 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 - is applied; conversely, - indicates a polarity in which it expands when + is applied and contracts when - is applied. .

Then, every other polarized electrode is given 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 14 of the elastic body 12, and the rotor 20 is rotated by this traveling wave. 22.23 is a sine wave power source and a cosine wave power source shown for convenience, and when the sine wave and the COS wave applied to the six polarized electrodes are reversed, the rotation direction of the rotor 20 is reversed.

The above is the basic configuration of the electrostrictive motor proposed in JP-A-58-148682. The details of the reasons for the generation of traveling waves are left in the same publication, but this motor has already been widely used.

On the other hand, the present applicant has developed an electrostrictive motor that does not rely on traveling waves based on the electrostrictive motor described above, and has filed a patent application. FIGS. 6(A) and 6(CB) show an example of polarization processing for this purpose, the poles to which the frequency voltage is applied by the frequency voltage source 25, and the relationship in the rotational direction of the rotor 20. This electrostrictive motor satisfies the basic principle of polarization processing applied to the electrostrictive element 11, which is to provide specific voltage applying devices on the left and right sides of a voltage application pole with the same polarity and different polarity as the voltage application pole. The rotor 20 can be driven by a single-phase frequency voltage, and the rotor 20 is 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
If the thickness of the electrostrictive element 11 is constant, the voltage applied to the electrostrictive element 11 is determined by the size of the wave to be generated at the interface 14 of the elastic body 12. In the conventional structure described above, it is possible to save energy by reducing the applied voltage. I couldn't figure it out.

``Object of the Invention'' The present invention is to obtain an electrostrictive motor that can transmit the expansion and contraction of an electrostrictive element to an elastic body by expanding the amount of expansion and contraction of an electrostrictive element to an elastic body, not depending on the magnitude of the applied voltage. The purpose is to obtain an energy-saving electrostrictive motor that operates in the same manner as conventional motors.

"Summary of the Invention J The present invention provides an electrostrictive element having a laminated structure, and if the electrostrictive element of this laminated structure is stretched at the upper and lower middle portions, and the other is contracted, the driving voltage can be lowered. This invention was completed based on the idea that the elastic body can have the required elongation of It has a laminated structure consisting of a plurality of layered electrostrictive elements in the thickness direction, and a common electrode is formed in the middle part,
It is characterized in that predetermined frequency voltages of the same frequency but with a phase difference of 180° are applied between the layered electrostrictive elements above and below the common electrode.

"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 3] is composed of two layered electrostrictive elements 31a and 31b. A common electrode 32 is located between both layered elements, and separation electrodes 33 are attached and formed on the surfaces of both layered elements 31a, 31F) at the same positions. These common electrode 32 and separate electrode 33
is composed of, for example, silver paste.

The layered electrostrictive elements 31a, 311) are subjected to a predetermined polarization process using the common electrode 32 and the separated electrode 331Fr, and are coupled to the elastic body 12 to form the vibrator 1.
It becomes 0.

In the present invention, the electrostrictive element 31 has a laminated structure, and the phase of the frequency voltage applied to the electrostrictive element 31 is adjusted to the intermediate common electrode 32.
By making the upper and lower portions different, for example, with a conventional low driving voltage of 172, the electrostrictive element 31 can be caused to expand and contract the same as before, or with the same driving voltage as the conventional one, it can be made to expand and contract twice as much as before. The purpose is to generate effective waves at the interface of the body 12.

Let's take the aforementioned traveling wave electrostrictive motor as an example.
Separate electrodes 16 on the front and back sides of the layered electrostrictive element 3]a, 31t) are provided with sine wave power sources 22 and C, which are shown separately for convenience.
In the present invention, a frequency voltage is applied from the OS wave power source 23, a phase inversion circuit 34, 35 is inserted in one of the circuits from these power sources to the separation electrodes 16 on the front and back, and the layered voltage at the same position on the front and back is inserted. The phases of the frequency voltages applied to the strain elements 31a and 31b are made different by ``+ao''.In other words, when a ◆sin wave (÷COS wave) is applied to the layered electrostrictive element 31a on the front side, the phase of the frequency voltage applied to the strain elements 31a and 31b is made different. Layered electrostrictive element 31t
) is given a -5in wave (-COS wave). Then, the electrostrictive element 31 as a whole expands on one side and contracts on the other side, so when trying to generate the same traveling wave at the interface 14 of the elastic element 12, the conventional device's 172
This means that it can be driven with a voltage of . If the same driving voltage as in the conventional device is applied, the traveling wave generated at the interface 14 will be large.

The above is a case of an electrostrictive motor using a traveling wave, but the story is similar in the case of an electrostrictive motor using a standing wave.

In the above embodiment, the layered electrostrictive elements 31a and 31b were provided above and below the common electrode 32, respectively.
A plurality of laminated electrostrictive elements may be provided above and below C length, respectively, and a driving voltage may be applied between these laminated electrostrictive elements.According to this embodiment, the thickness of each laminated electrostrictive element can be made thinner. , the drive voltage can be lowered considerably. Of course, the phase of the driving voltage is made different between the upper and lower portions of the common electrode 32.

Note that the present invention can of course be applied to a near motor in which the electrostrictive element 3178 is developed in a linear manner, and in this case, the mover is a linear mover.

"Effects of the Invention" As described above, the electrostrictive motor of the present invention has a laminated structure of the electrostrictive elements for obtaining the driving force, and has a common electrode interposed between them, and the upper and lower portions of the common electrode. By applying predetermined frequency voltages of the same frequency but with a phase difference of 180° between the layered electrostrictive elements, waves generated at the interface of the elastic body due to expansion and contraction of the electrostrictive elements can be obtained with a lower driving voltage. can. Alternatively, larger waves can be obtained with the same driving voltage. Therefore, an efficient and energy-saving electrostrictive motor can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a sectional view corresponding to FIG. 5, showing an example of the laminated structure and electrode wiring of the electrostrictive element used in the electrostrictive motor of the present invention, and FIG. A sectional view showing an example of a mechanical configuration, FIG. 3 is a sectional view taken along line m-m in FIG. 2,
FIG. 4 is a plan view showing an example of the polarization process for the electrostrictive element and the frequency voltage applied thereto, FIG. 5 is a schematic cross-sectional view along the v-V line in FIG. 4, and FIGS. B) is a plan view showing an example of the polarization process of F3 to another electrostrictive motor and the frequency voltage applied thereto. 1o... Vibrator, 11... Electrostrictive element, 12... Elastic body, 14-... Interface, 22.23.25... Frequency power supply, 31... Electrostrictive element, 31a, 31b ...Layered electrostrictive element, 32...Common electrode, 33...Separate electrode, 3
4, 35...phase inversion circuit. Patent Applicant Alps Electric Co., Ltd. Agent Kunio Miura Shigeru Matsui Figure 2 Figure 3 Figure 4 Figure 5 (A) CB) Figure 6 Temauri Nehomasa “I!” (Spontaneous) December 5, 1988 Commissioner of the Japan Patent Office Kuro 1) Mr. Akio 1, Indication of the case 2) Name of the invention Electrostrictive motor 3, Person making the amendment Relationship to the case Patent applicant address Yukitani Otsuka, Ota-ku, Tokyo Town No. 1-7 Name (
809) Alpur Electric Co., Ltd. Representative Kataoka Kataoka 4, Agent address: 106-3 Yonban-cho, Chiyoda-ku, Tokyo 102
, Contents of correction (1) "180° phase" on page 4, line 4 of the specification is corrected to "90° phase."that's all

Claims (3)

[Claims] (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 a predetermined frequency voltage is applied between the front and back sides of the electrostrictive element. In an electrostrictive motor that is polarized so as to apply a moving force to the movable element through waves generated at the interface due to expansion and contraction when the electrostrictive element is A common electrode is formed in the middle part of the laminated structure, and a predetermined frequency voltage having the same frequency but having a phase difference of 180° is applied between the layered electrostrictive elements above and below this common electrode. electrostrictive motor. (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 linearly, and the moving element is a linear moving element.