A piezoelectric micromotor using in-plane shearing of PZT elements

A torsional micromotor, 3×4×8.5mm, was developed using planar bulk lead zirconium titantate placed upon a small rectangular prism made from phosphor bronze, with a tapered conical horn and a machined interior. By using a new measurement technique, the torque and efficiency versus speed were measured at several combinations of applied voltage and preload. At 87.1-mN preload, up to 0.1-N·mm torque and 425r/min in both directions were obtained by driving the system at resonance, 186.3kHz for counter-clockwise rotation, and 240.6kHz for clockwise rotation, while the overall efficiency peaked at slightly above 40%.