Title :
Piezoelectric ultrasonic motor using longitudinal-torsional composite resonance vibration
Author :
Ohnishi, Osamu ; Myohga, Osamu ; Uchikawa, Tadao ; Tamegai, Masashi ; Inoue, Takeshi ; Takahashi, Sadayuki
Author_Institution :
NEC Corp., Kawasaki, Japan
Abstract :
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/sub 33/ and k/sub 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.<>
Keywords :
finite element analysis; piezoelectric motors; piezoelectric oscillations; torque; 2.5 ms; 20 mm; 40 percent; efficiency; electromechanical coupling factors; finite element method analysis; longitudinal mode; longitudinal-torsional composite resonance vibration; piezoelectric ceramic elements; piezoelectric stiffened modes; piezoelectric ultrasonic motor; resonant frequencies; rotational speed; torque characteristics; torsional modes; Couplings; Delay; National electric code; Resonance; Resonant frequency; Rotors; Stators; Torque; Ultrasonic transducers; Vibrations;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
