Development of High Stiffness Hydrostatic Gas Bearing Spindle with Two Circumferential Grooves

本文介绍了新研制的由两个外径100 ~ 110 mm推力轴承和一个长50mm、直径50mm的径向轴承组成的槽形空气轴承主轴的设计和实测数据。在第一次开发中，尽一切努力增加轴承刚度，结果取得了成功。然而，发现轴承阻尼反而降低了。然后，在第二次开发中，进行了优化平衡设计，通过稍微降低刚度来增加阻尼。本课题所做的工作和结果总结如下：(1)本文提出的数值分析方法可以定量预测气膜的刚度和阻尼。(2)提出了新的设计方法，优化了静气轴承径向、角向和推力方向的刚度以及主轴共振处的Q因子。(3)建立了试验模态分析方法，用于识别共振时的模态参数、振型和动刚度。(4)研制的空气主轴在0.49 MPa下径向刚度为110N/<micrn>m，推力刚度为500n /<micrn>m，角刚度为3.5*10^5 Nm/rad。耗风量小于10nl /min。(5)所研制的主轴在径向、推力和角模共振处的Q系数分别为15、16和10。这个项目是成功的，因为上面描述的性能是相当或优于最好的空气主轴的这种类型。

This paper desctibes the design and measured data of the newly developed grooved air berings spindle which is composed of two thrust beatings of 100-110 mm outer diameter and one radial bearing of 50 mm length and 50 mm diameter. In the first development, every efforts were devoted to increasing the bearing stiffness and the results were successful. However, the bearing damping was found to be reduced on the contrarty. Then, in the second development, the optimal balanced design was performed to increase the damping by decreasing the stiffness slightly. The works and results done in this project are summatized as follows:(1) The numerical analysis method developed here can predict quantitatively the the stiffness and damping or air film.(2) The new design method was developed to optimize the statical air bearing stiffness in the radial, angular and thrust directions and Q factors at resonances of the spindle.(3) The experimental modal analysis method was developed for identifying the modal parameters, vibration modes and synamic stiffness at resonance.(4) The air spindle developed here has 110N/<micrn>m radial stiffness, 500 N/<micrn>m thrust stiffness and 3.5*10^5 Nm/rad angular stiffness under 0.49 MPa. The air consumption is less than 10 Nl/min.(5) The developed spindle has Q factors of 15, 16 and 10 at the radial, thrust and angular mode resonances, respectively.This project was successful because the performances desctibed above are comparable to or better than that of the best available air spindle of this kind.