ACTUATOR

PROBLEM TO BE SOLVED: To provide an actuator that can be efficiently driven without matching a driving frequency with the resonance frequency of the actuator. SOLUTION: When piezoelectric bodies 21, 22, 23, 24 provided on the seat 13 of a shaft 11 are supplied with a predetermined driving signal with the identical timing, the piezoelectric bodies 21, 22, 23, 24 are synchronously expanded and contracted. At this time, rotation vibration is produced in the shaft 11 by alternately repeating forward rotation and reverse rotation around the axis. As a result, a moving member 12 is moved in the direction of the axis of the shaft 11. Since it is unnecessary to match the frequency of the driving signal with the resonance frequency of the actuator, a problem of degradation in drive efficiency due to frequency deviation is eliminated. COPYRIGHT: (C)2009,JPO&INPIT