ULTRASONIC WAVE ACTUATOR AND DRIVING GEAR USING SAME

PURPOSE:To form the device of high efficiency at a low cost by arranging a resonator and a fastening member to be fixed with fastening bolts on both the sides of a piezoelectric element in the axial core direction, and by shifting the centroid of the resonator positionally from the axial core of the arrangement. CONSTITUTION:An ultrasonic wave actuator 1 is composed of a piezoelectric element 2 and a resonator 3, a fastening member 4, and fastening bolts 5 for fixing them to each other. On the shell section of a resonance rod 3, two groove- shaped void sections 6, 7 orthogonal to an axis line are formed at positions shifted from each other by 90 degrees. When an ascending force due to the piezoelectric element is worked on the resonance rod 3, then the force passes the central shaft 9 of the resonance rod, but the centroid of the resonance rod 3 is positionally shifted from the central shaft 9, and so a couple is generated, and the resonance rod 3 starts deflecting oscillation. Then, the sections of the voids 6, 7 also start the deflecting oscillation, but the positions of respective centroids are different, and so the direction of oscillation is to be different. Accordingly, at the tip of the resonance rod 3, the deflecting oscillation is generated.