| 摘要 |
PURPOSE:To increase a rotary torque by generating elastic vibration advancing circumferentially along the cylindrical surface in contact of a rotor with a stator and generating the rotor. CONSTITUTION:When a rotor cylinder 20 is rotated, a predetermined DC voltage is applied to linearly moving electrode rows 15, 16 to contract cylindrical piezoelectric ceramics 13 of this part and to increase the inner diameter of this part. Thus, frictions between frictional strips 21, 23 and the ceramics 13 are reduced, and the contact of the strips 21, 23 with the ceramics 13 does not disturb the rotation of the cylinder 20. A predetermined AC signal is applied to a rotary electrode row 14 in this state, and a circumferential traveling wave is generated by the elastic vibration on the inner periphery of the ceramics 13 of the part. Thus, the cylinder 20 in contact with the strip 22 is rotated according to the circumferential traveling wave. |
