Dynamic Characteristics Analysis on Bearingless Motorized Spindle Rotor System

The bearingless motorized spindle is an ideal high speed spindle structure, which has the advantages of both magnetic levitation motorized spindle and bearingless motor. The dynamic characteristics of its rotor system which are the results of the combined effect of rotor structure performance and support properties of bearingless motor and magnetic bearing, affects the dynamic characteristics of the whole spindle system and even the machine tool. In this paper, the design process and dynamic characteristics of the bearingless motorized spindle are discussed. The modal analysis of the rotor system is carried out by ANSYS Workbench. The natural frequencies and vibration modes of the rotor under different stiffness are obtained. The influence of the support stiffness on the dynamic characteristics of the rotor is also studied. It provides a theoretical basis for the structure optimization and the control system design of the bearingless motorized spindle.