A piezoelectric micromotor using in-plane shearing of PZT elements

A torsional micromotor, 3 x 4 x 8.5 mm, 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 425 r/min in both directions were obtained by driving the system at resonance, 186.3 kHz for counter-clockwise rotation, and 240.6 kHz for clockwise rotation, while the overall efficiency peaked at slightly above 40%