节流器结构参数对Nanosys-1000液体静压导轨承载特性的影响

Influence of restrictor structural parameters on load-bearing characteristics of Nanosys-1000 hydrostatic guideway

从实际加工角度出发,研究了节流器结构参数对Nanosys-1000超精密加工机床静压导轨承载特性的影响。利用流体分析软件建立导轨承载油垫的有限元模型并搭建了相关静压导轨实验台,研究了进口油压为1.7 MPa,油膜厚度为36μm时承载油垫的压力场分布特征,并通过对压力场积分得到油膜承载力,求导得到油膜刚度,从而揭示不同结构参数对静压导轨承载特性的影响。研究结果表明:节流器结构参数中节流孔孔径对机床承载特性影响最大,其次为节流孔孔长,出入口倒角对其影响甚微。导轨负载较小时,扩大节流孔孔径与缩短节流孔孔长有助于改善静压导轨承载特性;但在重载条件下,缩小节流孔直径,增加节流孔孔长反而更有利。将仿真数据与实验数据作对比,得到3个承载力测量点数据误差分别为7.9%,6.9%,8.6%。最后根据研究成果,确定了Nanosys-1000机床静压导轨节流孔结构参数。

On the basis of practical machining, influences of structural parameters of a restrictor on the load-bearing characteristics of hydrostatic guideway in the Nanosys-1000 ultra precision machine tool were analyzed. The fluid analysis software was used to establish the finite element model of a carrying oil pad and build a related hydrostatic guideway test bench. The pressure field distribution characteristics of the carrying oil pad when its inlet pressure was 1.7 MPa and the oil film thickness was 36 μm were researched. By integrating the pressure to get the oil film capacity, the oil film stiffness was obtained by derivation, and the effects of the different structural parameters on the loadbearing characteristics of hydrostatic guideway were revealed. The results show that the orifice diameter has the greatest impact on the load-bearing characteristics of the ultra precision machine tool, followed by the orifice hole length, while the entrance and export chamfers have little effect on it. When the guide load is lower, expanding the orifice diameter and shortening the hole length can help to improve the load-bearing characteristics of the hydrostatic guideway. However, narrowing the orifice diameter and increasing the length of the orifice hole would be more favorable. As compared with the simulation data and the experimental ones, data errors of three capacity measuring points are 7.9%, 6. 9%, 8. 6 %, respectively. Finally, according to research results, the restrictor structural parameters of hydrostatic guideway in the Nanosys-1000 ultra precision machine tool were determined.