Study on the thermal behavior of hydrostatic motorized spindles for hard turning-grinding machines

Abstract

To investigate the influence of the thermal characteristics of a hydrostatic motorized spindle on the overall thermal stability of an ultra-precision hard turning and grinding machine tool, this paper takes the hydrostatic workpiece spindle of such a machine tool as the research object. A thermal analysis model is established that comprehensively considers motor losses, friction heat generation of hydrostatic bearings, and multiple forms of convective heat transfer. The finite element method is used to analyze the temperature rise process and steady-state temperature field distribution of the spindle under 4000 rpm operating conditions, and the accuracy of the model is verified through temperature rise experiments. The results show that the spindle reaches a thermal steady state after 1800 seconds of operation, with a maximum temperature rise of approximately 16 °C. The relative error between simulated and experimental temperatures is less than 1.13%, validating the effectiveness of the proposed model. The hydrostatic workpiece spindle is identified as a key factor influencing the overall thermal stability of the machine tool. The established thermal characteristic analysis model can provide a theoretical basis for subsequent thermal deformation control and thermal error compensation of the spindle system.