JPH0632794Y2 - Electrostrictive motor - Google Patents

Description

[Technical Field] The present invention relates to an electrostrictive motor, and more particularly to an electrostrictive motor capable of generating and driving an oscillating wave (standing wave) with a single-phase frequency voltage.

“Prior art and its problems” Various types of motors using electrostrictive elements have been proposed in the past. Among them, linear motion is generated by a traveling wave composed of transverse and longitudinal waves excited at the interface of an ultrasonic transducer. A (linear motor) or a device which obtains a rotary motion was first proposed in Japanese Patent Laid-Open No. 58-148682. Since a motor using this ultrasonic vibration generates a traveling wave by a composite wave of a transverse wave and a longitudinal wave, it is necessary to apply two or more frequency voltages having different phases to the electrostrictive element. However, in order to obtain frequency voltages having different phases, a complicated power supply circuit is required and a complicated wiring for applying this to the electrostrictive element polarized in a specific direction is required.

The applicant has already developed and applied for an electrostrictive motor that can be driven by a single-phase frequency voltage (Japanese Patent Application No. 61-233456). This electrostrictive motor includes a vibrator having an electrostrictive element bonded to an elastic body, and a mover that contacts the interface of the elastic body of the vibrator. The electrostrictive element is polarized so as to include a direct expansion / contraction pole for applying a frequency voltage and associated expansion / contraction poles located on the right and left sides of the direct expansion / contraction pole with a space in the moving direction of the mover. In addition, the direction of polarization of these expansion / contraction poles is such that the direct expansion / contraction pole and one of the associated expansion / contraction poles on the left and right thereof have the same polarity, and the other associated expansion / contraction pole has a different polarity.

According to the electrostrictive element that has been subjected to such a polarization treatment, an oscillating wave that imparts a moving force to the moving element, which is a standing wave, is generated in the elastic body bonded to this, and the moving element rotates or moves linearly. Can be made.

However, in this electrostrictive motor, the direct expansion and contraction poles to which the frequency voltage should be applied are arranged at intervals, and when the rotation direction is reversed, the positions of the direct expansion and contraction poles are different, so the wiring process is Although it is simpler than a conventional motor that applies two or more different frequency voltages, it is not always simple and there is room for improvement.

"Purpose of Invention" The present invention can be driven by a single-phase frequency voltage,
Moreover, it is an object of the present invention to propose an electrostrictive motor with a simple wiring process, simplify the power supply circuit, and further simplify the wiring process.

[Outline of the Invention] The electrostrictive motor of the present invention includes a vibrator having an electrostrictive element bonded to an elastic body, and a mover that contacts the interface of the elastic body of the vibrator. The electrostrictive element is composed of a plurality of laminated electrostrictive elements which are composed of two groups. That is, one group is an electrostrictive element in which the polarization processing direction is alternately changed at intervals in the moving direction of the mover, and the other group is the polarization of the first electrostrictive element group. It is an electrostrictive element group in which the phase is shifted by about half of the polarization processing interval with respect to the processing. One of each of the two groups is sufficient as the minimum unit, but if the number of the two groups is increased, a large driving force can be obtained, and if the thickness is the same as a whole, power consumption can be saved.

According to the above configuration, a single-phase frequency voltage is applied to the one of the first electrostrictive element group and the second electrostrictive element group by the single-phase frequency voltage applying means. It can be driven.
The rotation direction can be selected depending on which of the first and second laminated electrostrictive element groups is applied with a single-phase frequency voltage. When rotation in only one direction is required, a single-phase frequency voltage may be applied to only one electrostrictive element group.

"Embodiment of the Invention" The present invention will be described below with reference to illustrated embodiments. 1 to 3 show an example of a mechanical structure when the electrostrictive motor according to the present invention is applied to a rotary motor. The vibrator 10 to be fixed is a ring-shaped or disc-shaped electrostrictive element 11. It comprises an annular elastic body 12 bonded onto the electrostrictive element 11. The elastic body 12 is made of, for example, a metal material such as an Al alloy or stainless steel, and its upper surface is formed in a sawtooth shape in order to expand a vibration wave generated by the electrostrictive element 11.

A rotor 20 coaxial with the electrostrictive element 11 and the elastic body 12 is located on the vibrator 10. This rotor 20 has its axis 21
Is inserted into the bearing 13 of the vibrator 10, and the lower end face thereof is brought into contact with the interface (upper end face) 14 of the elastic body 12. The rotor 20 is rotated by a vibration wave (standing wave) generated at the interface 14 by a frequency voltage applied to the electrostrictive element 11.

Therefore, next, the structure of the electrostrictive element 11 and the polarization treatment applied thereto will be described with reference to FIGS. In the present invention, the electrostrictive element 11 has a laminated structure of the first electrostrictive element 11a and the second electrostrictive element 11b, and the electrostrictive elements 11a and 11b are The phases are different. That is, both the electrostrictive elements 11a and 11b are polarized at equal intervals (45 ° in this embodiment) with the positive and negative polarities shown in the figure. (22.5 °). + Is a property of contracting when + of the frequency voltage is applied, and expanding when − is applied, and conversely − is a polarity of expanding when + is applied and contracting when − is applied.

As shown in FIG. 5, a common electrode 15 made of, for example, a silver electrode is sandwiched between the electrostrictive elements 11a and 11b, and
On the front surface of the electrostrictive element 11b and on the back surface of the electrostrictive element 11b.
6 and 17 are attached. These electrodes 15, 16 and 17 are annular uniform electrodes. In the polarization treatment of the electrostrictive elements 11a and 11b, it goes without saying that electrodes on the front and back sides of the electrodes are provided at intervals of 45 ° and the polarization treatment is performed using these electrodes.

A single-phase frequency voltage from a frequency power supply 19 is applied between the common electrode 15 and the surface electrode 16 and between the common electrode 15 and the surface electrode 17 via the switch means 18, respectively. That is, the electrostrictive elements 11a and 11b are selected to be either one and a single-phase frequency voltage is applied.

The electrostrictive motor configured as described above, when a single-phase frequency voltage from the frequency power supply 19 is applied to the electrostrictive element 11a, the rotor 20 rotates clockwise, and when the same voltage is applied to the electrostrictive element 11b, the rotor rotates. The child 20 rotates counterclockwise.

The following is an inference of the reason. When a frequency voltage is applied to the electrostrictive element 11a, the + polarized electrode expands at the + voltage,
Reduce with a voltage of-. The-polarization treatment electrode contracts at a voltage of + and expands at a voltage of-. Therefore, if the electrostrictive element
Assuming that 11b does not exist, the electrostrictive element 11a simply repeats partial up and down vibrations (standing waves), and
It is considered that no force is generated to drive the rotor 20 to rotate.

However, the electrostrictive element 11b is superposed below the electrostrictive element 11a, and the phase thereof is shifted by half the polarization processing interval. Therefore, due to the leakage voltage of the frequency voltage applied to the electrostrictive element 11a, the + polarization processing pole and the − polarization processing pole of the electrostrictive element 11b are smaller than the electrostrictive element 11a, but similarly expand and contract. Then, the standing wave generated by the electrostrictive element 11a is overlapped with the small standing wave generated by the electrostrictive element 11b, and since the phases thereof are different, the interface 14 of the elastic body 12 has one direction. A standing wave including a falling component is generated. As a result, the rotor 20 rotates.

When a frequency voltage is applied to the electrostrictive element 11b, the standing wave falls in the opposite direction. Therefore, the rotor 20 will be reversed.

The above is one reasoning about the rotation principle of the electrostrictive motor of the present invention, but the operation of the electrostrictive motor of the present invention has been actually confirmed. Therefore, even if it operates on a principle different from the above, the right of the present invention cannot be narrowed.

A linear motor can be obtained by linearly expanding the electrostrictive element 11. In this case, the rotor is a linear mover. In the case of this linear motor, there are further advantages. That is, the conventional traveling wave electrostrictive motor can be applied to a linear motor in principle, but if it is actually applied, a problem of traveling wave reflection occurs. Since the end point of the oscillator always exists, the traveling wave is reflected at this end point. This reflected wave is obviously combined with the traveling wave that is the driving force of the linear motor, and the optimum driving force cannot be obtained. Therefore, some sort of traveling wave absorbing device is required. In contrast,
Since the present invention obtains the driving force by the standing wave, the problem of such reflected wave basically does not occur. Therefore, a linear motor having a simpler structure can be obtained.

In the above embodiment, each of the electrostrictive elements 11a and 11b has one layer, but each of them can have a plurality of layers. A larger driving force can be obtained by using a plurality of layers. Further, if the electrostrictive elements 11a and 11b have the same overall thickness, the power consumption is smaller when they are formed in a plurality of layers. Furthermore, electrostrictive elements 11a and 11b
It is possible to make the rotational torque different depending on the rotation direction by making the number of laminated layers different from each other.

“Effect of Device” As described above, according to the electrostrictive motor of the present invention, the mover can be moved by the single-phase frequency voltage. Therefore, if the polarization direction of the electrostrictive element is annular, the rotary motor
A linear motor can be obtained by making it linear. The electrostrictive element is composed of two groups of laminated electrostrictive elements, and the phase of polarization processing between the laminated elements is different. The direction of movement can be reversed simply by giving. Therefore, it is possible to simplify the connection to the drive power supply circuit and the electrostrictive element, and to provide a cheaper electrostrictive motor as a whole.

[Brief description of drawings]

1 is a sectional view showing an embodiment of the electrostrictive motor of the present invention, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG. 3 is a sectional view taken along the line III-III in FIG. 4 and 5 are schematic exploded perspective views showing polarization treatment of an electrostrictive element and a phase shift state, and FIG. 5 is a vertical sectional view of the same. 10 ... Oscillator, 11 ... Electrostrictive element, 11a, 11b ... Electrostrictive element, 12 ... Elastic body, 14 ... Interface, 15 ... Common electrode, 16,
17 …… Surface electrode, 18 …… Switch means, 19 …… Frequency power supply, 20 …… Rotor (mover), 21 …… Axis.

Continuation of front page (56) Reference JP-A-60-210172 (JP, A) JP-A-60-207469 (JP, A) JP-A-60-91877 (JP, A) JP-A-62-225181 (JP , A) JP-A-62-244284 (JP, A) JP-A-63-190569 (JP, A)

Claims (4)

[Scope of utility model registration request] 1. An electrostrictive motor comprising: a vibrator having an electrostrictive element bonded to an elastic body; and a mover in contact with an interface of the elastic body of the vibrator, wherein the electrostrictive element is a movable body. A first electrostrictive element group in which the polarization processing directions are alternately changed at intervals with respect to the moving direction of the child; the first electrostrictive element group and the polarization processing are the same,
A second electrostrictive element group, the phase of which is different from that of the first electrostrictive element group by a half of the polarization processing interval; and the first electrostrictive element An electrostrictive motor characterized in that a frequency voltage applying means for applying a frequency voltage of a single phase is provided in either one of the group and the second electrostrictive element group. 2. In the claim 1 of the utility model registration claim,
The electrostrictive element has an annular polarization process, and the rotor is a rotor. 3. A utility model registration claim as set forth in claim 1.
The electrostrictive element has a linear polarization process, and the moving element is a linear moving element. 4. Claims 1 to 3 of the utility model registration claim.
In any one of the paragraphs, the frequency voltage applying means has a switch means for applying a single-phase frequency voltage by selecting one of the first electrostrictive element group and the second electrostrictive element group. Electrostrictive motor.