Thermo-mechanical coupling analysis of a high-speed actuating mechanism based on a new thermal contact resistance model

Abstract

Present thermal models for analyzing the thermo or thermo-mechanical characteristics of machine tools either neglect the effect of thermal contact resistance (TCR) between rough solid surfaces or neglect the asperities’ long transition process from elastic deformation to plastic one in calculating TCR, which cannot reflect real engineering practice. To improve the simulation accuracy of the thermo-mechanical characteristics of a high-speed actuating mechanism, a new TCR model is proposed considering the multiple deformation states of asperities including elastic, elastic-plastic and plastic deformations. The formulae for calculating the heat generation powers at bearings and the convective heat transfer coefficients are also proposed. The validity of the proposed thermal model is verified by a comparison analysis of the simulated and measured transient temperatures at a series of measurement points. Finally, both the transient and steady thermo-mechanical coupling characteristics of the high-speed actuating mechanism are analyzed by integrating the force loads and the thermal loads obtained by the proposed thermal model, which provide a theoretical basis for the further optimization of the mechanism’s structural parameters and lubrication system.