考虑结构热变形的机床进给系统热误差研究

为系统研究精密机床进给系统热误差的形成机理及其影响因素,提出了一种考虑结构热变形的进给系统热误差建模方法。在考虑进给系统内生热源及冷却系统对丝杠螺母副的温升和丝杠热变形作用机制的前提下,同时考虑了进给系统内生热源对精密机床结构大件(床身、立柱、溜板)热态特性的影响规律。通过分析结构热变形引起的进给系统电机座和轴承座相对位置的变化,建立了综合考虑结构大件和丝杠热变形的进给系统热误差模型。以JIG630精密卧式加工中心为例,进行了考虑结构热变形和不考虑结构热变形的进给系统热误差建模与仿真分析,并开展了相应的测试验证实验。结果表明考虑结构热变形的进给系统热误差模型仿真值与实验结果具有更高的一致性。该建模方法对精密机床进给系统热平衡设计、热误差的控制与补偿具有重要参考意义。

Research on thermal error of machine tool feed system considering structural thermal deformation

To systematically study mechanism and factors affecting the thermal error of feed system of precision machine tools, a modeling method for the thermal error of the feed system considering the structural thermal deformation is proposed. Besides analyzing the temperature changing and thermal deformation of screw caused by inner heat resources in feed system and cooling system, the influence of inner heat source in feed system on the thermal characteristics of large structural components(bed, pillar, slide) of precision machine tool was also considered. The relative position changing between motor-box and bear-box of the feed system caused by the structural thermal deformation was analyzed, and a thermal error model of feed system considering the thermal deformation of large parts and screw was established. Thermal errors of the feed system of JIG630 precision horizontal machining center were simulated and modeled with and without considering the structural thermal deformation, and the corresponding verification experiments were carried out. The results illustrated that the thermal error model of the feed system considering the structural thermal deformation was more consistent with the experimental results. This modeling method is of great importance for thermal balance design, thermal error control and compensation of feed system of precision machine tools.