A comprehensive study of the effect of thermal deformation on the dynamic characteristics of the high-speed spindle unit with various preload forces

In this paper, based on the multi-degree-of-freedom (M-DOF) finite element and 2-dimensional transient thermal network methods, a novel thermo-mechanical coupling model of the highspeed spindle-bearing system by comprehensively considering the radial coupling deformations of supporting ball bearings and rotor is proposed, and the effects of the temperature rise and thermal deformation on its dynamic characteristics are discussed. Then a non-contact electromagnetic loading device is designed to test the dynamic amplitude-frequency response of a hydraulic variable preload experimental spindle system. The studies show that, the results calculated by proposed thermo-mechanical coupling model are highly consistent with the experimental results of the spindles system, and the temperature rise and thermal deformations have an important influence on its mechanical behavior, and the linear resonant frequency of the high-speed spindle under the constant pressure preload mechanism continues to increase until the system reaches its thermal equilibrium state.