Analysis Of Thermal Character Of High-speed Spindle System Based On Thermal Contact Resistance

Thermal characteristics analysis of spindle system plays an important role in thedynamic design of machine tool, and the thermal performance affects the machiningaccuracy of machine tool directly. The key of analysis is to establish accurate thermalfield. This paper carries on basic applied research on the thermal characteristics ofspindle system of ADGM35high-speed precision CNC lathe of national science andtechnology major projects "high-grade CNC machine tools and basic manufacturingequipment"(2012ZX04005-021) by the methods of finite element simulation analysisand test. The main works are as follows:The structure of ADGM35high-speed precision CNC lathe spindle system andthe mechanism of thermal deformation are analyzed, and the calorific values arecalculated. The way of heat transfer of spindle system is studied, the influence law ofcooling water velocity and qualitative temperature, bearing lubrication gas flow rateand temperature on convective heat transfer coefficient are obtained. On the basis,judge the cooling state of the motorized spindle systems, and select the appropriatevelocity of cooling water and lubricant gas. A testing device of solid-solid interfacecontact thermal resistance is designed to research the influence rules of pressure andsurface roughness on thermal contact resistance, and receive the estimation model ofthermal contact resistance. It provide the basis for contact parameters processing.ADGM35motorized spindle system simplified model is established by the finiteelement analysis software, ANSYS. In the boundary conditions of system heating rateand convective heat transfer coefficients, the thermal characteristics based on thecontact resistance between spindle and bearing, bearing and bearing hole, spindle andthe rotor are analyzed. It is found that the system temperature considering thermalcontact resistance is6-10℃higher than that without consideringthermal contactresistance, and the temperature of rear bearing joint place on spindle decreased by 2.33℃, and the temperature of front bearing joint place on spindle increased by1.04℃.