Patent ID: 7960925

Claim:
A method of driving an ultrasonic motor configured so that two alternating voltages having a predetermined difference between respective phases and having predetermined drive frequencies are applied to a piezoelectric element that has driving parts abutting a member to be driven, whereby simultaneous excitation of vertical and bending vibrations and hence excitation of an elliptical vibration occur in the piezoelectric element, and the driving parts receiving drive force from the elliptical vibration drive the member to be driven, the method comprising: performing wear particle removal drive at a fixed frequency during regular reciprocal drive so as to intermittently interrupt the regular reciprocal drive, the regular reciprocal drive being such that the driving parts repeatedly reciprocally drive the driven member within a predetermined drive range, and the wear particle removal drive being such that the driving parts reciprocally drive the driven member within a drive range wider than the predetermined drive range.