【作者】 张云；

【导师】 冯凯； 黄鹏程；

【作者基本信息】 湖南大学 ， 机械工程（专业学位）， 2018， 硕士

【摘要】 多孔质静压气体轴承因其摩擦系数非常小,承载力大,结构简单,刚度和阻尼性能好,使其广泛应用于精密机械。多孔质轴承由外界提供高压气体,气体通过多孔质材料,由于多孔质材料内部有许多微小的气孔,每个气孔相当于一个节流孔,使多孔质轴承表面形成一层高压气膜,用于承载物体。由于多孔质轴承内部气体流动模型较复杂,受外界供气压,轴承参数,加工制作等影响较大,且目前主要研究多孔质轴承在低速、重载情况下的应用,对轴承在高速应用下的研究较少。因此,本文首先建立多孔质轴承的静态理论模型,探究不同的因素对多孔质轴承特性的影响;设计可倾瓦多孔质轴承支承的高速转子系统,研究其振动特性。本文主要研究内容和取得成果如下:(1)基于达西定律和质量守恒方程,建立了多孔质静压气体止推轴承的静态气体流动理论模型,给出边界条件,对其进行数值求解。探究了不同渗透率多孔质材料,多孔质材料厚度对轴承气体质量流量、承载力和刚度等静态性能的影响,设计实验与理论对比,验证了所建理论模型的正确性。(2)设计可倾瓦多孔质静压气体轴承支承的高速转子系统。设计两根转子轴,分别用于刚性轴和柔性轴的研究。计算可倾瓦多孔质轴承的动态刚度和阻尼系数后,用XLrotor对设计转子系统进行转子动力学仿真,分析系统的临界转速,稳定性,幅值放大系数等,使其能够满足设计要求,转动性能良好。(3)设计了曲面弧度分别为60°和75°两种结构的可倾瓦多孔质静压气体轴承,对转子系统性能进行初步转动研究。曲面弧度60°的轴承对轴悬浮效果不是太好,转动时涡轮驱动气压较大,曲面弧度75°的轴承悬浮效果较好。实验结果表明转子系统振幅较小,但是高倍频较多。更多还原

【Abstract】 Porous aerostatic bearing has widely used in precision machinery,because of its small friction coefficient,large bearing capacity,simple structure,good rigidity and damping properties.Porous aerostatic bearing is an external air supply bearing and there are many tiny pores inside the porous material.When air pass through porous materials,porous aerostatic bearing can form a high pressure film on the surface to suspend the weight.Gas flow model of Porous aerostatic bearing is complicated,because the external supply pressure,the structure parameter of bearings,machining technology plays an important role in it;At present,the application of porous aerostatic bearing in low speed and heavy load is studied,but there are few studies about porous aerostatic bearing in high speed.Therefore,in this thesis,the static theoretical model of porous bearing is established,and the influence of different factors on bearing performance is explored;A high speed rotor system supported by tilting pad porous bearing is designed and its vibration characteristics are studied.The main studies of this paper are as follows:(1)Based on Darcy’s law and mass conservation equation,a theoretical model of static gas flow in a porous hydrostatic thrust bearing is established,then the boundary conditions are given and the model is solved.The effects of porous materials with different permeability and thickness of porous materials on the static performance of bearing gas mass flow,bearing capacity and stiffness were investigated;the correctness of the theoretical model is verified by comparing the design experiment with the theory.(2)High speed rotor system supported by tilting pad porous static gas bearing is designed.Two rotor shafts are designed for the study of rigid and flexible shafts.After calculating the dynamic stiffness and damping coefficient of tilting pad porous bearing,the rotor dynamics of the designed rotor system is simulated with XLrotor,and the critical speed,stability and amplitude magnification factor of the system are analyzed in order to the design can meet the design requirements and the rotation performance is good.(3)Tilting pad porous hydrostatic bearings with curved surface radians of 60 °and 75 °was designed,then the rotor system performance was studied.The bearing with 60 °curved curve is not very effective on shaft suspension,and the bearing with 75 °curved curve has better suspension effect than the bearing with 60 °curved curve.The experimental results show that the amplitude of the rotor system is small,but there are many the high frequency in test.更多还原