Butterfly-shaped ultra slim piezoelectric ultrasonic linear motor

A new piezoelectric ultrasonic linear motor, shaped 'Butterfly' wings, has been developed for use in thin electronic products, such as cellular phones and PDAs. The butterfly piezoelectric transducer with a volume of 9 mm × 8 mm × 1 mm is composed of an elastic plate which includes a tip for energy transfer, two protrusions, and two piezoelectric ceramics. The ultra slim butterfly motor with a thickness of ∼1 mm could be achieved by positioning the layered piezoelectric transducer and a linear guide in parallel. The manufactured motor based on FEM analysis was successfully driven at the resonance frequency range that combines the longitudinal and transverse vibration modes. The maximum velocity of 88 mm/s was achieved at a driving frequency close to the pure vibration modes such as the longitudinal or transverse modes. In opposite, the maximum thrust force of 162 g was obtained at a middle frequency between two vibration modes.