Improvement of the longitudinal vibration system for the hybrid transducerultrasonic motor

This paper presents a symmetric hybrid transducer ultrasonic motor designed to produce large longitudinal vibration stress in the rotor/stator contact interface for high-torque operation. The nodal plane of the longitudinal V ibration mode was adjusted to match the rotor/stator contact interface, and the piezoelectric ceramic disks for the longitudinal vibration mere instal led at the nodal plane of the longitudinal vibration mode for effective exc itation. An experimental motor, 20 mm in diameter, using the first torsiona l vibration mode and the second longitudinal vibration mode was manufacture d. A maximum torque of 0.8 N.m was achieved in the prototype, an improvemen t over previous versions.