【摘要】 大规格数控(CNC)成形磨齿机Z轴进给系统在加工过程中产生大量热量,导致立柱及导轨的倾斜、俯仰变形,影响加工精度。针对这一现象,提出了一种考虑接触热阻的瞬态热-结构耦合分析方法。该方法基于分形理论计算结合面间的接触热阻,并计算热源发热量及各部件的对流换热系数,综合考虑内部热源、边界条件和接触热阻建立综合有限元模型,获得热误差有限元仿真结果。分析了在是否考虑接触热阻情况下,Z轴导轨温度及热变形变化差异。最后搭建Z轴进给系统热误差测量试验平台,验证了该方法的准确性和可靠性。通过仿真得到温度变化及热位移量与试验值基本一致。更多还原

【Abstract】 The Z-axis feeding system of large computer numerical control(CNC) gear grinding machine tools generates a large amount of heat during the processing, which leads to tilt and pitch deformation of the Z-axis guideway and reduces the machining accuracy. In view of the above-mentioned facts, a transient thermal-structure coupling analysis method was proposed with thermal contact resistance(TCR) been taken into account. The thermal contact resistance at the joints was calculated using fractal theory. The heat from the source and the convective heat transfer coefficient of each component were calculated, and a comprehensive finite element model was established with regard to internal heat source, boundary condition and thermal contact resistance. Finite element simulation results of the thermal error were obtained. The temperature and thermal deformation of the Z-axis guideway were analyzed when thermal contact resistance was taken into consideration. The thermal error experimental platform of the Z-axis feeding system was set up, and the accuracy and reliability of the method were verified. Results showed that the temperature and thermal displacement were in accord with the experimental data.更多还原