精密钻削电主轴静压气体止推轴承润滑参数动态优选设计

DYNAMIC DESIGN ON THE EXTERNALLY PRESSURIZED GAS THRUST BEARING FOR PRECISION DRILL ELECTRIC SPINDLE

针对气体轴承的传统工程算法效率低,计算误差大,难以满足精密电主轴气体轴承设计要求的问题,在建立精密钻削电主轴轴向闭式支承物理模型的基础上,结合静压气体止推轴承润滑理论分析,运用有限元方法对雷诺方程进行离散求解。基于Matlab工具平台,采用超松弛迭代法编写了求解气体静压止推轴承压力方程组、承载能力和刚度的计算软件,实现了气体止推轴承润滑参数动态优选设计。通过该软件的计算仿真,得到了正在开发的PCB钻削电主轴静压气体止推轴承气膜间隙、节流孔直径、供气压力与轴承承载能力及刚度的曲线;以最大刚度为优化目标,最终确定了该电主轴止推轴承的最优润滑参数。

To deal with the problems of low calculation efficiency and great error on traditional engineering algorittlm in gas bearing design of precision electric spindle, the axial bearing physical model of precision drill electric spindle was established. Based on the lubrication theory analysis of externally pressurized gas thrust bearing, the Reynolds equation in eylindrieal coordinates was discretized by using the finite element method. Furthermore, a program was developed to solve the pressure equations, load capacity and stiffness of the bearing using the super relaxation iteration method for simulation on the basis of Matlab tools. It had achieved the dynamic optimization design of lubrication parameters to the gas thrust bearing. At last, through simulation, the relation curves of orifice diameter, gas fihn clearance, gas supply pressure and bearing characteristics were obtained on the externally pressurized gas thrust bearing of PCB precision drill electric spindle which is being developed by author. The optimization parameters of the gas bearing were got by analyzing the simulation results while the maximum stiffness was the optimization target.