| 摘要 |
PURPOSE:To take out rotational torque of an ultrasonic motor efficiently. CONSTITUTION:In an ultrasonic motor comprising an oscillator 12 and a rotor 13 being driven by the oscillator 12, the oscillator 12 comprises an elastic tubular body 14, a plurality of drivers 15a-15d protruding from the inner peripheral face of the tubular body 14, and two groups (phase A and phase B) of even number of piezoelectric elements 16a-16d, 17a-17d arranged on the outer peripheral face of the tubular body 14, whereas the rotor 13 is disposed in the oscillator 12 such that the rotor 13 comes into contact with the drivers 15a-15d. When two groups of piezoelectric elements are excited by applying AC voltages respectively, the rotor 13 rotates in a predetermined direction whereas when the phase of voltage to be applied to any one group (e.g. phase B) of piezoelectric elements is varied, the rotor 13 is rotated reversely. |
