Thermal characteristic analysis of high-speed motorized spindle system based on thermal contact resistance and thermal-conduction resistance

In view of thermal resistance problem of the motorized spindle system, this paper proposes a thermal resistance network model of spindle-bearing-bearing pedestal based on the fractal and Hertz contact theory. According to this model and Kirchhoff's law, the heat balance equations for thermal nodes are established and solved with Gauss-Seidel iterative method to gain temperature values of the main thermal nodes. In order to accurately understand thermal characteristics of the motorized spindle system, the effect of thermal contact resistance and thermal-conduction resistance is taken into consideration. Thermal simulation analysis is carried out on the motorized spindle system. On a precision horizontal machining center, the temperature rise of motorized spindle parts is implemented under different rotational speeds with LMS data acquisition system. It is shown that temperature values based on thermal resistance network model agree well with those of simulation analysis and experimental results. What is more, the whole thermal deformations of the main components of the motorized spindle system are analyzed.