Thermal characteristics analysis and experimental study on high-speed spindle system

A three-dimensional finite element analysis (FEA) model was proposed to conduct transient thermal-structure interactive analysis of high-speed spindle systems in order to avoid the degeneration of high-speed spindle's machining accuracy in actual machining caused by an excessive temperature rise at the design stage. However, thermal contact conductance (TCC) was often ignored in traditional thermal models of high-speed spindles. Which caused inaccuracies in traditional thermal models. The FEA model considered TCC to improve the accuracy of traditional thermal models. The Weierstrass-Mandelbrot function was used to characterize the rough surface morphology of bearing rings. The fractal parameters were identified by combing the power spectrum method with the measurement data of bearing ring's surface morphology. And a contact mechanics model was proposed to calculate the contact parameters used in the modeling of TCC. Then, an integrated geometry-mechanical-thermal model for TCC was proposed, which effectively avoided the inaccuracies of statistical methods and the poor generality of experimental measurements. The heat generation of the built-in motor and rolling bearing was calculated based on the efficiency analysis method and quasi-static mechanics analysis, respectively. According to the Reynolds number, the flow status of the fluid was determined, and the convective heat transfer coefficients of spindle components were calculated based on the Nusselt number. The above boundary conditions were applied to the FEA model, and thermal characteristics experiments were conducted to demonstrate the validity of the FEA model. The results show that the simulation precision of the FEA model is superior to that of the traditional thermal properly analysis models which ignor TCC.