| 摘要 |
PROBLEM TO BE SOLVED: To efficiently drive the rotor of an ultrasonic motor by generating a similar progressive wave as the theoretical wave, by making the resonance frequency of a vibrating body correspond to each electrode group nearly agree by adjusting the screwing depths of screws for adjusting resonance frequency in tapped holes. SOLUTION: An ultrasonic motor is rotatably supported by a rotating shaft 4 by means of a stator (vibrating body) 5, which is put on and fixed to a fixing the base 3 and has a circular outer periphery and a bearing 7 fixed to the fixing base 3 through the central part of the stator 5 and base 3. A rotor 6 which faces the stator 5 and has a circular outer periphery is press-contacted with the stator 5 by means of a compression spring 11. Four tapped holes 5s for adjusting resonance frequency are formed on the outer peripheral surface of the outer peripheral section of the stator 5, in such a way that the holes 5s have their opened ends on the outer peripheral surface, and are arranged at regular intervals of an mechanical angle of 90 deg. in the circumferential direction. Brass screws 13 are respectively screwed in the holes 5s. The resonance frequency of the stator 5 corresponding to each electrode group can be made to nearly agree, by adjusting the screwing depths of the screws 13 in tapped holes 5s. |
