| 摘要 |
PROBLEM TO BE SOLVED: To attain high-accurate rotating speed control, and thin and miniaturize the while of a device. SOLUTION: This ultrasonic motor 1 is provided with a position detecting means 30, 35 for detecting the condition of the rotational movement of a movable body 15, and a member 20 to be read forming a pattern to be read is integrated with the movable body 15 to detect the condition of the rotational movement of the movable body 15 by the position detecting means 30, 35. A position detecting point K by the position detecting means 30, 35 is positioned so as to meet the position between pressure means 7, 8 for bringing the movable body 15 into contact with an oscillator 10 at prescribed pressure and the oscillator 10 in the longitudinal direction of the rotating shaft 5 of the movable body 15. The position detecting point K is disposed so as to meet an inner position than the outer periphery of the oscillator 10. |
