Invention Grant
US07834515B2 Drive apparatus 有权
驱动装置

Drive apparatus
Abstract:
A drive apparatus includes an ultrasonic motor that rotates by an electromechanical transducer element, and generates an intermittent signal that outputs an alternating signal without change only during ON times of a pulse signal as a driving signal for the ultrasonic motor. A voltage is applied to the ultrasonic motor based on the driving signal to intermittently drive the ultrasonic motor, thereby reducing (adjusting) the speed of the ultrasonic motor. By setting the frequency of the intermittent signal (the inverse of a period of the intermittent signal) to a frequency outside the audible frequency range during the intermittent drive, noise can be easily lowered.
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