A High Speed Ultrasonic Linear Motor Using Longitudinal and Bending Multimode Bolt-Clamped Langevin Type Transducer

An ultrasonic linear motor using longitudinal and bending vibration double mode bolt-clamped Langevin type transducer was proposed and fabricated to achieve high speed. The elliptical trajectory of the driving tip was formed by exciting the longitudinal vibration and the bending vibration with 50 degree or -130 degree phase difference, which generate driving force and frictional force respectively. To achieve high linear speed, exponential shape transducer horn was adopted when the motor was designed due to its characteristic of magnifying vibration amplitude and vibration velocity. The classical theory of transducer horn was used to determine the transducer's longitudinal resonance frequency and its configuration dimensions. FEM method was employed to tune the longitudinal and bending vibration resonance frequencies. Typical output performances of the prototype are no-load velocity of 850 mm/s and maximum driving force of 50 N