| 摘要 |
PURPOSE:To solve the qualitative problem, such as delay and stopping of the timepiece by the influence of an external magnetic field by providing a driving means to be rotated by the oscillation waves of an elastic body on a rotor which is brought into pressurized contact with the above-mentioned elastic body. CONSTITUTION:The rotor 3, the central shaft 3-c of which is retained by a leaf spring 4, is brought into pressurized contact with a stator 1 and the efficiency of an ultrasonic motor is enhanced by regulating this pressurizing force thereof, by which the regulation of the output torque is executed. This ultrasonic rotor is merely necessitated to be impressed with a frequency voltage only for the time when the rotor moves by a step angle (=15 deg.). Then, the smaller current consumption is required and, therefore, there is the advantage that the life of a battery is prolonged. |
