Abstract:

In view of the low simulation accuracy of existing finite element models for thermal characteristics of spindles caused by ignoring the influences of geometric characteristics of convective surfaces and fluid flow patterns and often adopting constant temperature loading in the setting of convective heat transfer boundary conditions, this paper proposed an optimization method for convective heat transfer parameters of spindles based on finite element thermal analysis. Combined with the geometric shapes and spatial positions of various convective surfaces of the spindle system, the calculation criterion of the convective heat transfer coefficient was determined through dimensional analysis according to the similarity principle; a heat transfer model considering fluid flow patterns (natural convection/forced convection/Taylor-Couette flow) was established, and a real-time dynamic temperature loading mechanism was introduced into the finite element simulation. Through the thermal characteristic experiment of the spindle system of a Baoji CH7520 numerical control lathe, the effectiveness of this optimized model was verified. The simulation experiment results show that the optimized model can more accurately predict the temperature field and thermal deformation of the spindle, and its simulation accuracy is significantly higher than that of traditional methods ignoring geometric factors and flow patterns and adopting constant temperature loading. This study provides a reliable modeling basis for the thermal error compensation of high-precision machine tools.

Key words: thermal analysis, thermal characteristic, convective heat transfer, parameter optimization, temperature field, deformation field