Ultrasonic actuator installed in ultrasonic motor for generating asymmetric acoustic bending-shear standing wave, has generators that are arranged asymmetrically with respect to plane of symmetry for generating asymmetric standing wave

摘要

The ultrasonic actuator (3) has piezoelectric element (4) on which friction element (8) is arranged. The piezoelectric element has electrode surfaces (6,7) on which excitation electrodes (9) and general electrodes (10) are arranged. The piezoelectric element is polarized in direction perpendicular to electrode plane direction. The friction element, exciting electrodes, and general electrode are arranged symmetrically to plane of symmetry (S). Generators (16,17) are arranged asymmetrically with respect to plane of symmetry for generating the asymmetric standing waves.