竖直静压圆柱导轨系统运动误差理论模型研究

Modeling on Motion Error of Vertical Hydrostatic Cylindrical Guideways

针对双面抛光机床中竖直静压圆柱导轨运动误差影响被加工零件平行度的难题,提出一种基于压力油膜误差均化效应的运动误差理论模型。考虑圆柱导轨轮廓误差并对油膜厚度进行均化处理,建立圆柱导轨轮廓误差分析模型,求解各油垫的油膜承载力,量化竖直静压圆柱导轨系统在运动过程中产生的线性偏差和角度偏差。进一步,从初始设计油膜间隙、设计节流比、供油压力三个方面研究圆柱导轨轮廓误差对运动误差的影响机制。通过实验测得圆柱导轨轮廓误差曲线,并根据最小二乘法进行数据拟合,得到圆柱导轨轮廓误差函数并计算出实际倾角误差。圆柱导轨轮廓误差模型的计算结果与仿真结果相差2.4%,与实验结果相差9.2%,圆柱导轨轮廓误差模型适用于工程实践。结果表明:建立的竖直静压圆柱导轨系统运动误差理论模型精度高,可为竖直静压圆柱导轨精度分析和工程应用提供理论基础。

A theoretical model of motion error based on the error averaging effect of the pressured oil film is proposed to overcome the challenge posed by the parallelism of the machined parts which attributed to the motion error of the vertical hydrostatic cylindrical guideways in the double-sided polishing machine tool.The contour error of the cylindrical guideways are considered and the thickness of the oil film is equalized to establish an analysis model,solving the oil film bearing capacity of each pad,and quantifying the linear and angular deviations generated in the running process.Furthermore,the influence mechanism of the contour error of the cylindrical guideways on the motion error is studied considering the initial nominal oil film gap,the restrict ratio and the oil supply pressure.The contour error curve of the cylindrical guideways are measured through experiments,and the data are fitted according to the least square method to obtain the contour error function,and the actual inclination angle error is calculated.The difference between the calculation results of the cylindrical guideways profile error model and the simulation results is 2.4%,with a difference 9.2%compared with the experimental results.The cylindrical guideways profile error model is suitable for engineering practice.The results show that the established theoretical model of the motion error has high accuracy,which can provide a theoretical basis for the accuracy analysis and engineering application of the vertical hydrostatic cylindrical guideways.