Contact Analysis and Output Characteristics of Longitudinal-Torsional Ultrasonic Motors

In order to improve the torque and the efficiency of longitudinal-torsional ultrasonic motor, this paper makes an analysis on friction links of stator and rotor of this type motor, and in the thesis the motor performance improvement on torque and efficiency is come down to getting the maximum friction state between stator and rotor of the motor, also the contacting process of stator and rotor is regarded as the two process superposition along axial direction and circumferential direction respectively. Based on this, first, the relationship between motor frequency of longitudinal vibration and torsional vibration and rotor impact force in longitudinal and circumferential directions is defined. Secondly, the thesis discusses the detailed functions of motor drive voltage, pre-tightening force and vibration frequency for the motor improvement on torque and efficiency. Finally, the thesis points out some problems needed attention in such motor design to obtain higher torque and efficiency, so to improve the motor performance.