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

本文介绍了新研制的槽式气垫轴的设计和测量数据，它由两个外径100-110 mm的推力轴承和一个长50 mm、直径50 mm的径向轴承组成。在第一次开发中，我们不遗余力地提高轴承的刚度，并取得了成功。然而，轴承的阻尼却相反地被降低了。然后，在二次开发中，进行了最优平衡设计，通过略微降低刚度来增加减振效果。本课题所做的工作和取得的成果如下：(1)提出的数值分析方法可以定量地预测空气轴承的刚度、阻尼力或气膜。(2)提出了一种新的设计方法来优化主轴径向、角向和推力方向的静空气轴承刚度和主轴共振时的Q系数。(3)建立了识别主轴共振时的模态参数、振型和动力学刚度的实验模态分析方法。(4)研制的空气主轴具有110N/lt；microrn&gt；m径向刚度，500N/lt；microrn&gt；M推力刚度和3.5Nm/rad角刚度(0.49 Mpa)。(5)研制的主轴在径向、推力和角模共振时的Q值分别为15、16和10，达到或优于目前国内最好的空气主轴的性能。

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.