Modeling and analyzing multi-variable coupling thermal characteristics for motorized spindle

Considering the coupling behaviors between the non-linear mechanics character and the thermal effect, a dynamic heat calculation model for rolling bearings taking heat-induced preload and temperature-viscosity effect into account is established. A thermo-structural coupling calculation method introducing the thermal contact resistance is developed according to the coupling parameters in the motorized spindle system. The temperature rising and thermal deformation tests are carried out to verify the accuracy of this model and algorithm, and the thermal characteristics of the motorized spindle are analyzed. It is found that the simulation results coincide well with the experimental data under different working conditions to indicate the effect of the proposed model on improving simulation precision. The temperature field distribution of the spindle trends high inside and low outside. The thermal expansion of spindle caused by the heat accumulation of shaft mainly affects the manufacturing accuracy. During the temperature rising process, the preload of bearings decreases due to the fitting manner and the assembly position.