| 摘要 |
PURPOSE:To improve energy efficiency, to obtain low speed and high torque and to improve responding properties by setting the radial oscillation mode of a stator as a primary natural resonance oscillation mode. CONSTITUTION:The output signal of an oscillator 19 is divided into two parts, and one part is inputted directly to an amplifier 20 and the other part, to an amplifier 22 via a phase shifter 21. The output signal of the amplifier 20 is applied to a pair of electrodes of piezoelectric ceramic plate 14 and simultaneously the output of the amplifier 22, also to another pair of electrodes of piezoelectric ceramic plate 14. Then, a wave moving circumferential of the piezoelectric ceramic plate 14 is generated and transferred to a stator base 13. Thus, the radial oscillation mode of a stator 11 is set as a primary natural resonance oscillation mode, the friction material 17 of a rotor 12 comes into contact only with the wave front (the maximum point of a longitudinal displacement) of the wave transferred to the stator base 13, and the rotor 12 is rotation-driven via the friction material 17 in the direction opposite to that of progress of the wave moving circumferentially of the stator base 13. |
