某重型车床横向进给系统传动刚度分析与实验研究

A Study of Analysis and Experiment on Transmission Stiffness of the Transverse Feed System of a Type of Heavy Duty Lathe

进给伺服系统的性能对数控机床的跟踪及定位精度、加工表面质量等有着重要的作用。针对某重型车床的横向进给系统,综合考虑了轴的扭转刚度、齿轮的啮合刚度、丝杠螺母副接触刚度和丝杠支承轴承的轴向刚度等因素,建立了等效单自由度力学模型,分析刚度因素对工作台输出行为的影响。通过仿真计算分析了中间传动链各个刚度环节对工作台综合刚度的贡献量,找出了传动链的刚度薄弱环节。现场实验测试了工作台不同进给位置下的临界爬行速度,得到了临界爬行速度与丝杠的轴向刚度的关系,理论分析与实验结果相吻合。所得结论为该重型车床横向进给系统的优化设计提供了理论支持。

The performance of the feed servo system has an important effect on CNC machine tools, including the tracking and position accuracy as well as the surface quality of the machined part. The transverse feed system of a type of heavy duty lathe is investigated in this paper. The torsional stiffness of all shafts, engagement stiffness of the gears, contact stiffness of the ballscrew nut joint and the axial stiffness of the ballscrew bearing of the system are considered. The transverse feed system !is simplified to a SDOF model to analyze the effects of stiffness on the output behavior of the working： table. The weak part of the driving train is found out by analyzing the influence of each stiffness part in the driving chain on the synthesis stiffness through simulation. In the field test, the critical ,;tick slip feed velocities at different feed positions are measured and the relationship between the critical stick slip velocity and the axial stiffness of the ballscrew is obtained. The results of theoretical analysis and the experimental data match well. All the work can provide a research basis for the optimum design of the transverse feed system of the heavy duty lathe.