RU2560115C2 - Wave ultrasonic motor - Google Patents

Abstract

FIELD: electricity.

SUBSTANCE: invention relates to electrical engineering and can be used for drives rotating the small-sized devices. The wave ultrasonic motor contains a bimorph pizoelecric ring and a deformable ring rigidly joined with it and elastically enclosing a rotor. Between the deformable ring and the rotor there is a gap. On the ring surface and the rotor surface the fine-grained teeth are cut.

EFFECT: technical result consists in increase of rotating moment, efficiency and durability, decrease of friction losses.

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Description

The invention relates to the field of electrical engineering, automation and can be used for rotation drives of small-sized devices.

Known vibration motor (copyright certificate No. 619986, bull. No. 30, 1978) containing piezoelectric elements as an electromechanical transducer. For example, a vibroengine in which the transducer is made in the form of two identical segments of a piezoceramic ring. The disadvantages of this type of vibration motors are small torque and the presence of frictional contact between the converter and the rotor. This reduces the durability of the structure.

Known piezoelectric vibroengine (copyright certificate No. 624320, bull. No. 34, 1978), containing an electromechanical transducer made in the form of two piezoelectric elements in the form of ring segments with rectilinear jumpers. The disadvantages of this vibrator are the bulkiness of the converters and the fragility of the friction coupling of the rotor and the converter.

The vibroengine (copyright certificate No. 632014, publ. Bull. No. 41, 1978) has a piezoceramic vibrator made in the form of two piezoceramic elements mounted at an angle to each other, the ends of which are rigidly connected to the shoe pressed against the rotor. Disadvantages: unreliability and fragility of the friction contact.

The stepper motor (copyright certificate No. 674123, publ., Bull. No. 26, 1979) is intended for linear movements and cannot be used for rotation drives.

Disadvantages: unreliability and fragility of the friction contact.

Known wave vibrator (copyright certificate No. 595813, publ. Bull. No. 8, 1978), taken as a prototype. This engine contains a piezoelectric transducer made in the form of a bimorph piezoelectric ceramic ring with sectorized electrodes. A piezoceramic ring is rigidly connected to a deformable ring elastically enclosing the rotor.

To transmit motion in this engine, friction forces arising from the contact of the deformable element with the rotor are used. This predetermines its shortcomings. Firstly, the small torque of the engine. Secondly, the unreliability and fragility of the frictional contact. With prolonged use, the deformable ring wears out. In practice, this requires a complete replacement of the engine.

The technical result is to increase the magnitude of the torque, reduce friction losses, increase the efficiency of the engine, increase the durability of the engine.

The technical result is achieved by the fact that there is a gap between the deformable ring and the rotor, and finely modular teeth are cut on the surface of the ring and on the surface of the rotor.

The invention is illustrated in figure 1.2.

The gear surface of the rotor 1 is covered by a deformable gear wheel 2, which is rigidly connected to a bimorph piezoelectric ring 3 with sectorized electrodes.

The engine operates as follows.

When voltage is applied to the electrodes of the bimorph piezoelectric ring, the deformable ring is compressed in one direction and extended in the perpendicular direction, acquiring the shape of an ellipse. The teeth located at the ends of the minor axis of the ellipse will fully engage with the teeth of the rotor, and the teeth located at the ends of the major axis will completely disengage from the teeth of the rotor. The directions of deformations of the deformable ring will change synchronously with the voltage applied to the electrodes of the bimorph ring, and the contact points of the teeth will run all the time around the circle, and the rotor will rotate at a speed corresponding to the difference in the numbers of teeth of the deformable ring and the rotor. In the proposed piezoelectric engine, the gear ratio is

$$u=\frac{n_H}{n_P}=\frac{z_{\mathrm{one}}}{z_2-z_{\mathrm{one}}}$$

where n _H is the rotation frequency of the ellipse equal to the frequency of the voltage supplied to the electrodes of the bimorph piezoelectric ring; n _P is the rotor speed; z ₁ , z ₂ - the number of teeth of the deformable ring and rotor, respectively. The "u" times the magnitude of the torque in the proposed piezoelectric engine in comparison with the prototype. Usually u = 50 ... 60, therefore, the torque increases in 50 ... 60.

In the prototype, the rotor rotates using friction forces. As a result, increased wear of the deformable ring and the rotor surface is inevitable. And for such an engine, even insignificant wear of the ring is dangerous, since this leads to a sharp decrease in the friction forces, and therefore to a decrease in the torque of the engine. Therefore, the durability of such an engine is small and can be 1500 ... 2000 hours. The gear transmission used in the proposed engine has an almost unlimited service life.

Claims (1)

A wave piezoelectric motor containing a bimorphic piezoelectric ring and a deformable ring rigidly connected to it, elastically enclosing the rotor, characterized in that there is a gap between the deformable ring and the rotor, and finely modular teeth are cut on the surface of the ring and the rotor surface.

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