| 摘要 |
PROBLEM TO BE SOLVED: To properly control the rotation of a rotor without fail when both a stator and the rotor are provided with a piezoelectric vibrator. SOLUTION: Piezoelectric vibrators 5v, 6v are made of one and the same material and formed into one and the same shape, and at least the vibrating portions of elastic bodies 5e, 6e used for driving are made of one and the same material and formed into one and the same shape. The numbers of natural oscillations of oscillating bodies 5g, 6g comprising the piezoelectric vibrators 5v, 6v and at least the vibrating portions of the elastic bodies 5e, 6e used for driving are match with each other. When the piezoelectric vibrators 5v, 6v are supplied with a signal of the resonance frequency of the oscillating bodies 5g, 6g or a frequency close to the resonance frequency in this state, traveling waves produced at the pressure-welded faces can be method with each other. As a result, the rotation of the rotor 6 can be properly controlled properly by continuously shifting the engaging lock position of the traveling waves. In addition, since both the numbers of natural oscillations are shifted in the same direction by the same amount, the engaging lock of the traveling wave will not release and the rotation of the rotor 6 can be controlled properly without fail, even of the numbers of natural oscillations of the oscillating bodies 5g, 6g are shifted due to effects of temperature, humidity, load or the like. |
