| 摘要 |
PURPOSE:To improve practicability with high efficiency by giving the stator itself of a longitudinal one-torsional composite vibrator mutually approaching longitudinal and torsional resonance frequency. CONSTITUTION:A ring-shaped piezoelectric ceramic element 11 for exciting torsional vibrations is composed so as to hold a cylindrical block 12 and a block 13, to a base of which a hole, into which a bolt is penetrated, is bored, thus forming a torsional vibrator main section. A longitudinal driving element 14 fastened by a bolt is arranged inside the cylindrical block 12 and said element 11, and fixed and unified. The torsional vibrator main section and the longitudinal driving element 14 shape an integral composite vibrator 15 (a stator for an ultrasonic motor). Longitudinal resonance frequency and torsional resonance frequency can be made to approach remarkably by the constitution. The composite vibrator 15 is pressure-welded to the end face of the stator by using a rotor 16, a bearing 17, an abrasion-resistant material 18, a coil spring 26, etc., thus forming the ultrasonic motor. Accordingly, AC voltage is applied independently to both elements 11, 21, and the rotor 16 is rotated with high efficiency. |
