节流孔轴向布置方式对气浮主轴轴承特性的影响

Influence of Axial Arrangement of Orifices on Characteristics of Bearing in Air Bearing Spindle

气浮主轴承载能力和刚度作为衡量气浮主轴性能的关键指标,受到节流方式的直接影响,而目前节流孔轴向布置方式对孔式节流静压气体轴承支承性能的影响尚缺乏深入研究。为研究节流孔轴向布置方式对静压气体轴承特性的影响,设计两排孔、中部排气式四排孔、中部不排气式四排孔3种典型的节流孔轴向布置方式,基于雷诺方程建立静压气体轴颈轴承气膜力数学模型,分析轴芯转速、节流孔轴向布置方式对轴承承载力与刚度的影响规律,并通过实验验证模型的准确性。结果表明:在低速阶段,中部排气式四排孔结构轴承的承载力和刚度最大,适合低速重载工况;在高速阶段,中部不排气式四排孔结构轴承的承载力和刚度最大,其动压效应提升明显,尤其是长径比较大的轴承,适合高速工况;双排孔轴承兼顾了以上2种优势,适合性能均衡应用工况。通过实验验证了模型的准确性,研究结果可指导静压气体轴承在不同应用需求中的选用与设计。

The bearing capacity and stiffness are the key factors to measure the performance of air bearing spindles,which are directly affected by the throttling method.However,the influence of axial arrangement of the orifice on the supporting performance of the aerostatic gas bearing is lack of in-depth investigation at present.In order to study the influence of axial arrangement of orifice on the characteristics of aerostatic gas bearing,three typical throttling structures were designed,i ncluding two rows of holes,middle exhaust four-row-hole and middle non-exhaust four-row-hole.The mathematical model of gas film force of aerostatic gas bearing was established based on the Reynolds equation,and the influence of the shaft speed and the axial arrangement of the orifices on the bearing capacity and stiffness was analyzed.The accuracy of the model was verified through experiments.The results show that,in the low-speed stage,the bearing capacity and stiffness of the middle exhaust four-row-hole structure bearing is the largest,which is suitable for the application of low-speed and heavy-load working condition.In the high-speed stage,the bearing capacity and stiffness of the middle non-exhaust fourrow-hole structure bearing are the largest,and its dynamic pressure effect is obviously improved,especially the bearing with large length diameter ratio is suitable for high-speed working condition.The bearing of two rows of holes has the above two advantages and is suitable for balanced performance application.The accuracy of the model was verified through experiments,and the research results have the guiding significance for the selection and design of aerostatic gas bearings in different application requirements.