基于主轴轴承运行刚度的高速主轴动力学建模

Dynamic Characteristic Analysis of Motorized Spindle Based on Bearing Dynamic Stiffness

高速主轴是高速加工关键功能部件之一,其动力学性能对机床加工质量有着重要的影响。基于赫兹接触理论计算了主轴轴承动态运行刚度并构建了主轴轴承的刚度矩阵;基于Timoshenko梁理论获得高速旋转梁单元运动方程;基于主轴轴承单元、梁单元与盘单元构建了某高速主轴系统有限元模型,并进行了静动态实验测试。结果表明:所建立的动力学模型是准确的,为主轴系统结构优化提供了理论指导。

Based on quasi-dynamic model of rolling bearings,taking into account the influence of speed,initial preload,centrifugal force,gyroscopic moment on bearing stiffness,the running stiffness of bearings was calculated. The stiffness matrix of angular contact ball bearing was derived and calculated. The beam element equation of motion was derived based on Timoshenko rotating beam thoery. Using this as a foundation,the FEM of spindle was created. Experiments were done to measure the static stiffness,modal test and FRF of spindle. Comparing the experimental and calculated results,it is shown that the FEM of the spindle developed in this study can describe the dynamic characteristics of the spindle with an acceptable accuracy.