| 摘要 |
PURPOSE:To simplify a drive power supply by limiting the direction of polarization of a pair of ring-shaped piezoelectric ceramic elements and using a composite vibrator, in which torsional vibrations and longitudinal vibrations are generated simultaneously, as a stator. CONSTITUTION:An ultrasonic motor is composed of a stator consisting of a composite vibrator, in which torsional vibrations and longitudinal vibrations are generated simultaneously, and a rotor 14 arranged at the end section of the stator. The composite vibrator is constituted in such a manner that ring- shaped piezoelectric ceramic elements 10a, 10b, in which slip deformation in the circumferential direction and shrinkage deformation in the thickness direction are generated at the same time, are combined and paired, and the elements 10a, 10b are held by metallic members 11a, 12 from both sides. AC voltage is applied to one ring-shaped piezoelectric ceramic element 10a and the rotor 14 is turned in one direction, and a switch 19 is changed over and AC voltage is applied to the other element 10b and the rotor 14 is rotated in the direction opposite to said direction. Accordingly, phase need not be controlled, and a drive power supply is simplified. |
