Development of High Damping Hydrostatic Air Slider

(1)在对一维槽型轴承模型的分析中，发现槽数N_g、槽深G和槽宽L_g对Sigma=O处的静刚度影响不大，当N_g、G和L_g分别变大时，低Sigma区的阻尼B减小。但在高Sigma区，B随G的增加而增加，并且在Sigma&Lt；Opt&gt；处有一个极值B_&lt；Opt&gt；，该极值对应于分割区的局域压缩数Sigma‘。通过尽可能地减小L_g，选择N_g，使之与相应的固有频率相匹配，并将G增大到极限值，使B在低σ区保持正值，从而实现高共振频率下的高阻尼气浮轴承。(2)在分析一维轴承模型的基础上，提出了一种新型的梳状槽静压气体轴承滑块，它既能提供高的共振阻尼比，又能提供高的刚度。在高频区增加气膜阻尼的基本思想是通过梳状沟槽来减小气膜的压缩效应。结果表明，在保证0.3无量纲刚度的前提下，可以实现Zeta为0.23。(3)制作了四根梳形槽形支承的静压空气滑块。制造的滑块具有很高的静刚度，是传统沟槽空气轴承的1.2倍。阻尼比为0.065，是传统槽型空气轴承的2倍。如果实现更高精度的间隙和进给孔直径，并使用更多的刚性材料，就可以实现阻尼比在0.2以上的静压空气滑块。

The results of this research is as follows ;(1) In analysis of one dimensional grooved bearing model, it is found that groove number N_g, depth G and width L_g have little effect on static stiffness at sigma = O. The damping B in low sigma region decreases when N_g, G and L_g respectively become large. But B in high sigma region increases with the increase in G and has an extremum value B_<opt> at sigma_<opt> which corresponds to the local squeeze number sigma' of ten in the divided region. We can realize a high damping bearing at resonance frequency by decreasing L_g as small as possible, choosing N_g so as to tune sigma_<opt> to the corresponding natural frequency and increasing G to the limiting value which keeps B positive in low sigma region.(2) We propose a new hydrostatic air bearing slider with comb-shaped grooves based on the analysis of one dimensional bearing model which can provide high damping ratios at resonances as well as high stiffnesses. The basic idea to increase the air film damping at a high frequency region is to reduce the compressive effect of the air film by comb-shaped grooves. It is found that the zeta of 0.23 can be realized while assuring 0.3 non-dimensional stiffness.(3)We fabricate a hydrostatic air slider with four comb-shaped grooved beaxings. The fabricated slider has a high static stiffness which is 1.2 times the conventional grooved air bearing's one. Damping ratio is 0.065 which is 2.0 times the conventional grooved air bearing's one.We can realize the hydrostatic air slider whose damping ratio is above 0.2 if we will realize the higher accuracy clearance and feeding hole diameter and use more rigid material.