The contact mechanism of an ultrasonic motor

The mechanical characteristics of a ring-type ultrasonic motor are clarified. The finite-element method (FEM, MSC/NASTRAN) was used to obtain the shape of the elliptic motion at the surface point of projections. The vibration mode of projections was measured by using an electrooptical displacement transducer made by Zimmer KG. The accuracy of the simulation was confirmed by comparing the calculated results with the measured results. The dynamic contact condition of a stator and a rotor was calculated by using the FEM (JNIKE3D). The simulated displacements, T-N (torque-rotating-speed) curve, loss power and efficiency are compared with the experimental results.<>