数控机床主轴热特性分析

Analysis on Thermal Dynamic Characteristics of CNC Machine Tool Spindle

主轴热误差是数控机床热误差的主要组成部分,热弹性现象是交替变化的热源作用在构件上产生的,误差补偿是提高机床精度的最有效方法之一.为此,提出并分析了一维主轴热弹性现象产生的原因及其重要特征,并通过有限元分析和实验验证了热动态特性的存在及变化规律.随着时间的增长,温升-热变形之间的关系会逐渐趋近稳态,但不可能获得绝对的稳态.在传热过程中,随着传热距离的增加,温度变化滞后性越大.

Thermal error of a machine tool spindle is the key component of thermal error in total computer numerical control system. Thermo-elastic phenomenon is engendered as a result of the alternating heat source applied on object. Error compensation is one of the most effective methods to improve the accuracy of machine tools. The reason and important features of one-dimentional spindle thermo-elastic phenomenon were studied in this paper. Then the finite element method and experimental research were developed for further study to confirm the existence and variation of the heat dynamic characteristics. The conclusion is that the relationship between the thermal deformation and tempera- ture rising will gradually reach an equilibrium state, but the equilibrium state is not absolutely steady. During the heat transfer process, the hysteresis of the temperature variation grows quickly owing to the increase of transferring dis- tance.