| 摘要 |
PROBLEM TO BE SOLVED: To prevent the effects of the propagation of vibration on an ultrasonic motor which is capable of a plurality of outputs. SOLUTION: An elastic body 2 pasted with a piezoelectric body is provided with an inner annular section 4 and an outer annular section 5 which are separated in the radial direction by a circumferential groove 2c (2b) and serve for a plurality of concentrical resonators. Each of the ring-shaped sections is formed with a comb-like tooth section. Independent rotors are made to contact resiliently with the comb-like tooth sections of the ring-shaped sections respectively. The piezoelectric body is provided with an inner group of electrodes and an outer group of electrodes, each polarized to the degree set for the resonance frequency of each ring-shaped section, and is input with the high frequency voltage of the set degree for driving corresponding rotor. A plurality of through-holes 15 are formed in a bottom wall of the circumferential groove, which separates the annular sections and a un polarized section which is a space between each electrodes 13a (13b) of the inner annular section 4 is provided with a connecting section 6, which connects the inner and the outer annular section. Due to this structure, each annular section is free to vibrate and the resonators do not interfere with each other because propagation of vibration is prevented by means of the through-holes, and thereby independent driving forces can be obtained. |
