Hybrid Ultrasonic Motor With Side Panels Using Longitudinal-Torsional Vibration Modes

Hybrid Ultrasonic Motor Using Longitudinal-Torsional vibration modes has the characters of high output torque and excellent controllability, so that it is specially suited for those special fields,such as aerospace, Micro-automation equipment. However, the traditional Hybrid Ultrasonic Motor Using Longitudinal-Torsional vibration modes often uses the torsional vibration piezoelectric ceramic,which is polarized along circumference direction. and the structure of sandwich-transducer, so that the size of it cannot be minimized or the cost of its manufacture can't be reduced. Although in recent several years, some researchers presented a new series of transducers using the d31 effect of rectangle piezoelectric to exciting both working vibration modes, whose output performance isn't so good as expected and the fixed body of motor is unable to resolve. This paper focuses on problems about the cost of motor's manufacture, its miniature, the improvement of the exciting method by virtue of the d31 effect. By the way, in the process of research,this paper achieved the excitement of the stator'torsional vibration,succeeded in designing novel hybrid ultrasonic motors, reduced the cost of these motors' manufacture and also made it possible to lessen their size. Some main achievements are realized by this dissertation's researching,as follow:(1) A novel Strain-type hybrid ultrasonic motor is presented. Its principle is to use the d31 effect of piezoelectric element to excite 1st bending vibration modes of four side panels uniformly distributed along the circumference of the stator cylinder, and then the bending vibration modes induce 2nd torsional vibration mode of the stator. This motor can attain the largest output torque of0.048N·m and the highest no-load speed of 103 r/min?(2) The method of using the d15 effect of piezoelectric element to excite the torsional vibration of the stator in the traditional Stress-type hybrid ultrasonic motor will be replaced with the way of four side panels' dissymmetry bend inducing 1st torsion of stator. Thus a novel Stress-type hybrid ultrasonic motor with four side panels is presented, which has 20mm's outer diameter of the stator cylinder, and the stator‘s structure with four side panels is proved by the experiment to enable to producing 1st torsional vibration.(3) In order to research the miniaturization of the Stress-type hybrid ultrasonic motor with four side panels, a motor of this kind with the 10mm's outer diameter of the stator cylinder is presented.Experiment shows that the stator can be excited into 1st torsional vibration, and the frequency coherence between the torsional vibration mode and the longitudinal vibration is realized by debugging.