Ohnishi O, Myohga O, Uchikawa T, Tamegai M, Inoue T, Takahashi S
NEC Corp., Kawasaki.
IEEE Trans Ultrason Ferroelectr Freq Control. 1993;40(6):687-93. doi: 10.1109/58.248212.
A piezoelectric ultrasonic motor, which uses longitudinal and torsional composite vibration, is examined in order to obtain high torque characteristics with small diameter. Piezoelectric ceramic elements, oscillating in both longitudinal and torsional modes, respectively, are used as piezoelectric stiffened modes having high electromechanical coupling factors k(33) and k(15), respectively. It is found that the resonant frequencies for longitudinal mode and torsional mode could coincide with each other in the ultrasonic motor, according to finite element method analysis and experimental measurement. The motor operating in both resonant vibrations indicated good performance. The 20-mm diameter motor exhibited 4 kgfcm maximum torque, 450 r/min maximum rotational speed, 40% maximum efficiency, and quick responsiveness, within 2.5 ms.
为了在小直径情况下获得高扭矩特性，对一种采用纵向和扭转复合振动的压电超声电机进行了研究。分别以纵向和扭转模式振荡的压电陶瓷元件被用作分别具有高机电耦合系数k(33)和k(15)的压电强化模式。根据有限元法分析和实验测量发现，超声电机中纵向模式和扭转模式的共振频率可以相互重合。在两种共振振动下运行的电机表现出良好的性能。直径为20毫米的电机在2.5毫秒内展现出4千克力厘米的最大扭矩、450转/分钟的最大转速、40%的最大效率以及快速响应能力。
