JPH0532995B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ultrasonic motor useful as a drive device in various fields.

(Prior art and its problems) Various motor devices that apply electromagnetic force as a drive source have been widely used for various purposes.
However, in the case of these conventional motor devices, there are certain limitations on the size, weight, rotational force, etc. depending on the materials used, and it is difficult to reduce the size and weight of the motor devices.

This is because it is limited by the magnetic properties of the materials used.

On the other hand, as an alternative to these conventional motor devices, the applicant has proposed a motor device that uses ultrasonic vibration, that is, a motor device that is excited by a piezoelectric element on the surface of an elastic body that is an ultrasonic vibrator. A drive device has been proposed that converts a vibration wave into unidirectional motion of a moving object that presses into contact with the vibration wave.

By converting the powerful vibrational energy of ultrasonic waves into rotational or linear motion, a small and lightweight motor device is realized.

Although this ultrasonic motor device has attracted attention as having excellent features, there are still concrete issues that need to be improved.

In other words, generally, in order to produce the piezoelectric effect, a piezoelectric element is first applied with a high DC voltage.
It is well known that polarization treatment must be performed.

In particular, in the ultrasonic motor proposed by the inventor of this application, in order to generate bending waves in the stator, the piezoelectric element is polarized in opposite directions every half wavelength in the thickness direction. There must be.

In other words, in order to polarize the electrodes in opposite directions at every half wavelength, the electrodes must be separated into individual parts without being integrated. Therefore,
The piezoelectric element used in an ultrasonic motor has a large number of polarization electrodes, and by integrating the divided polarizations, the piezoelectric element is expanded and contracted in opposite directions every half wavelength, thereby generating bending waves. ing.

Therefore, after the polarization process, it was necessary to connect these electrodes by soldering, applying conductive paint, or connecting wires.

However, with these conventional conduction means,
The problem was that the work was tedious and unreliable.

(Means for Solving the Problems) Therefore, the present invention solves the above problems by providing an ultrasonic motor having a stator and a moving body, wherein the stator includes an elastic body, a piezoelectric element, The present invention provides an ultrasonic motor having a polarizing electrode, the polarizing electrode being interposed between the piezoelectric element and the elastic body.

(Function) More specifically, for example, the present invention uses a conductive material such as metal for the elastic body of the stator, and connects the polarization electrode surface of the piezoelectric element and the elastic body surface to each other by pressure bonding or the like. conduction between them to form one electrode,
The aim is to eliminate the need for continuity work such as soldering, conductive paint, and crossover wires, and to improve reliability.

(Example) FIG. 1 of the attached drawings shows a cross-sectional view of a ring-shaped stator, in which an external electrode 4 is provided on the upper surface of the piezoelectric element 2, and a polarization electrode 3 is provided on the lower surface. This polarization electrode 3 is fixedly supported by the metal elastic body 1, which has the function of providing electrical continuity between the polarization electrode 3 and the elastic body 1 at the same time as being mechanically fixed and supported by pressure bonding. It also has

The elastic body 1, the piezoelectric element 2, and the polarization electrode 3 constitute a stator, and the polarization electrode 3
is interposed between the piezoelectric element 2 and the elastic body 1.

Although not shown, a moving body comes into contact with the elastic body 1, and the traveling wave of the elastic body 1 excited by the piezoelectric element 2 drives the moving body.

FIG. 2 also shows a cross-sectional view of the ring-shaped stator. In this example, a piezoelectric element 2 having an external electrode 4 and a polarization electrode 3 is fitted into a groove of an elastic body 1, and is further caulked with the upper surface 1a of the elastic body 1 to be fixedly supported. At the same time, polarization electrode 3
and the elastic body 1 are electrically connected.

FIG. 3 shows a cross-sectional view of a cylindrical stator, in which a piezoelectric element 2 having an external electrode 4 and a polarization electrode 3 is shown.
is fixedly supported on the inner circumference of the cylindrical elastic body 1 by press-fitting or adhesive, and at the same time, the polarization electrode 3 and the elastic body 1 are electrically connected.

(Effects of the Invention) As explained above, the present invention fixes and supports the polarized electrode surface and the elastic body surface, which have been polarized, in contact with each other, thereby eliminating the large cost burden of the conventional conduction process. This can be avoided and, at the same time, reliability can be greatly improved.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing an example in which a piezoelectric element is bonded to a ring-shaped elastic body under pressure, FIG. 2 is a cross-sectional view showing an example in which a piezoelectric element is fixedly supported on a ring-shaped elastic body by caulking, FIG. 3 is a sectional view showing an example in which a piezoelectric element is fixedly supported by press-fitting or adhesion into a cylindrical elastic body. DESCRIPTION OF SYMBOLS 1... Elastic body, 1a... Upper surface of elastic body, 2... Piezoelectric element, 3... Polarization electrode, 4... External electrode.

Claims (1)

[Claims] 1 An ultrasonic motor having a stator and a moving body, wherein the stator has an elastic body 1, a piezoelectric element 2, and a polarization electrode 3, and the polarization electrode 3 has a piezoelectric element 2 and an elastic body 1. An ultrasonic motor that is interposed between the