An Optimal Equivalent Finite Element Modeling for a Hollow Shaft with Hot-fitted Motor Rotor

Abstract

Developing a motor built-in high speed spindle is an important key technology for domestic precision manufacturing industry. One of the major concerns in the process of designing a motor built-in high speed spindle is to mount the motor rotor on the shaft by hot-fitted to form a new rotor-shaft assembly. In this study, a hollow shaft with a hot-fitted motor rotor is considered. The study involves two stages. First, the modal testing is carried out on a bare hollow shaft. The modal parameters are used as a reference to ensure the adequacy of the subsequent finite element model of the hollow shaft. Secondly, the modal testing is conducted on the rotor-hollow shaft assembly. The modal testing results are then used as the optimization object for the subsequent finite element analyses. In order to model the increase of local stiffness of hollow shaft at the location of motor rotor, the optimal equivalent Young's Modulus is proposed in this paper. Based on the results of modal testing and numerical analyses, it may conclude that the proposed finite element modeling procedure for dealing with the dynamic analysis of hollow shaft with hot-fitted motor rotor is feasible and effective.