Simulation on thermal characteristics of high-speed motorized spindle

High-speed motorized spindle is a key component of precision machining machine. Thermal deformation caused by internal heat accumulation is one of the main factors affecting machining accuracy. Therefore, there is important theoretical and practical significance to accurately simulate and analyze thermal characteristics inside the spindle. In this paper, a three-dimensional finite element analysis model is established and the heat transfer mechanisms of the boundary conditions in the model. The temperature field and thermal displacement field of the spindle under thermal load are simulated. According to the simulation results, it is found that the overall temperature is radially distributed from the middle of the spindle core to surroundings after the temperature reaches dynamic equilibrium, and the axial (z-direction) thermal displacement is the largest, which is the main cause affecting the machining accuracy. Applying Peltier material to the spindle shell to decrease temperature difference and using carbon fiber material with negative coefficient of temperature expansion to restrain thermal deformation are proposed innovatively in this paper. The combination of those two methods shows that the optimized spindle temperature distribution is more uniform, and the thermal deformation reduces from 31.4 μm to 24.1 μm, which decrease by 23.2%.