The research on the steady characteristics of aerostatic thrust bearing for machine tool spindles with different parameters
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摘要: 超精密机床主轴一般采用静压气体轴承支承。文章应用大型商业计算流体软件Fluent，并结合MATLAB神经网络拟合工具箱，训练拟合出不同参数与轴承承载力及入流质量流量的映射关系函数，基于此，研究了不同参数对单节流孔圆形静压气体止推轴承静态特性影响的规律。首先，将计算的压力分布与文献中的实验数据进行对比，来验证计算模型与边界的正确性；然后，采用MATLAB神经网络拟合工具箱，训练拟合出轴承半径、节流孔孔径、气膜厚度和外界供气压力与轴承承载力及入流质量流量的映射关系函数；最后，研究了静压气体止推轴承外部供气结构对轴承压力分布的影响；气膜厚度、节流孔直径和供气压力对轴承承载力及入流质量流量的影响。结果表明：外部供气结构对轴承压力没有明显的影响；气膜厚度减少、孔径和外界供气压力的增大会增大轴承的承载力；气膜厚度、孔径和外界供气压力的增大都会增大入流质量流量。Abstract: The spindle of ultra precision machine tools is generally supported by aerostatic bearings. In this paper, fitting functions between different parameters and bearing load capacity and mass inflow rate are obtained by combined Fluent software with MATLAB neural network fitting toolbox. Then the effects of different parameters on the steady characteristics of aerostatic thrust bearings are studied by the fitting functions. Firstly, the numerical pressure distribution results calculated by the Fluent in the paper are compared to experimental data in the literature published in the past to verify the correctness of the calculation model and boundary condition. Secondly, the fitting functions between bearing diameter, orifice diameter, gas film thickness, supply pressure with load capacity and mass inflow rate are obtained by using MATLAB neural network fitting toolbox. Then, the influence of the external supply structure on the pressure distribution and the effects of gas film, orifice diameter and supply pressure on the load capacity and mass inflow rate are analyzed. The results shown that the external supply structure has no significant effect on the pressure distribution and the load capacity is increased with the decreasing the film thickness, the increasing the orifice diameter and supply pressure. Moreover, the mass inflow rate is increased with the increasing the film thickness, orifice diameter and supply pressure.
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Key words:
- Fluent /
- aerostatic bearing /
- inherent orifice /
- load capacity /
- mass inflow rate /
- neural network
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表 1 Fluent的层流模型、湍流模型计算的承载力和质量流量的结果对比
膜厚/
μm承载力/N 质量流量/（$ \mathrm{k}\mathrm{g}/\mathrm{s} $） 层流
模型湍流
模型相对误
差/（%）层流
模型湍流
模型相对误
差/（%）9 99.45 99.48 0.030 2 6.55×10-6 6.53×10-6 0.306 14 59.17 59.33 0.270 0 1.26×10-5 1.25×10-5 0.800 
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