Ultrasonic Piezomotor with Longitudinally Oscillating Amplitude-Transforming Resonator

Maximilian Fleischer, Dieter Stein, Hans Meixner

Research output: Contribution to journalArticle

28 Citations (Scopus)


Ultrasonic piezoelectric motors are distinguished by high torque at low speeds, short start-stop times and their inhibiting action in the off state. They consist of a metal resonator, which is stimulated by piezoelectric ceramics to produce oscillations with frequencies in the ultrasonic region, and a rotor that is driven by the resonator via a friction contact. The motor concept presented here is based on the transformation of the longitudinal oscillations of a rod-shaped resonator into continuous motion by arranging the resonator diagonally to a drum. The efficiency of the motor was enhanced by increasing the amplitude of motion at the point of motion transfer by tapering the resonator. To optimize the resonator design, the validity of the predictions derived from the one-dimensional analytical theory for longitudinal ultrasonic resonators was tested with respect to this application by means of finite-element calculations. The one-dimensional (1-D) calculation turned out to be hardly applicable at all to real resonators. The finite-element calculations showed that maximum final amplitude is attained when the resonator tapers as steeply as possible, no preference being shown for any special mathematical form of cross-sectional reduction. Efficiencies of 35 percent and torques of 25 Ncm were attained at 150 r/min.

Original languageEnglish
Pages (from-to)607-613
Number of pages7
JournalIEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
Issue number6
Publication statusPublished - Nov 1989


ASJC Scopus subject areas

  • Instrumentation
  • Acoustics and Ultrasonics
  • Electrical and Electronic Engineering

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