NON-HERTZIAN CONTACT MODELS FOR ULTRASONIC IMPACT MOTORS
Jürgen Jäger, Blattwiesenstr. 7, D-76227 Karlsruhe, Germany
2nd European Nonlinear Oscilations Conference, Prague, Sep. 9-13, 1996, eds.: L. Pust, F. Peterka, printed by: Publishing House of Czech Techn. University, Vol. 1, pp. 203-206
ABSTRACT: Ultrasonic motors are devices that can transform vibrations above 20 kHz into steady motion. A special type of these motors, consisting of a rod that hits a rotor under an acute angle to the contact normal, is studied in this paper. It is necessary to calculate the elastic deformation, because theclassical friction model of rigid body sliding can only predict dissipation but not energy conversion. Based on the half-space approximation, a quasi-static contact model is developed and different types of contact surfaces are consi dered. In order to arrive at a simple solution, some additional assumptions are introduced, such as small contact durations and constant impact velocities in the compresssion and restitution phase. Some dimensionless parameters for the steady state mode are derived and optimal values are calculated.