The influence of design parameters to the vibration modes on single-signal-drive-type ultrasonic motors using flexural disk vibrators

摘要

A same-phase drive-type ultrasonic motor is suitable to self-oscillation drive, because it can be driven by a single signal and change the revolution directions easily by selecting the driving electrodes of the piezoelectric ceramics. To realize stable self-oscillation drive, it is desired to design a vibrator without spurious. But it is difficult to apply conventional finite element method to the design of the vibrator because of the difference between analytical results and experimental ones. Furthermore we recognized the phenomena that some vibrators we made excite only one vibration mode largely and work as motors, which aren't based on the principle of the same-phase drive-type ultrasonic motor. So we investigated these phenomena with finite element method considering piezoelectric effect, and we also propose the design method of vibrators for self-oscillation drive based on the results gained through the analyses.