Contact Dynamics of the Rotor and Bearing Hub in Electrostatic Micromotor
静电微电机微转子接触动力学特性分析

A mathematical model of the contact between the rotor and bearing hub of electrostatic micromotor, which actuated MEMS, is constructed to investigate the contact dynamics. It is illustrated that the contact problem of the contact stress and strain equations can be presented under the scaling effects of micro-scale. The parameters, such as the geometries of the micromotor, the electrostatic force, the material characteristics and the applied gap voltages, which are related to the contact, are discussed in detail. The discriminations between unchanged gap and maximum changed gap under different applied voltages and various materials are studied. Some results about the contact width, the contact stress and the contact strain, are compared with finite element model (FEM) solutions of an equivalent problem. The von Mises stress and strain and contact pressure for expressing the distributions are presented. The effects of different friction coefficient on the von Mises stress and strain and contact pressure are discussed. The small differences between the both methods, showing characteristic features of FEM and the theoretical assumptions, are explained.