空气静压电主轴的流固耦合数值分析与实验研究

发布时间：2018-10-23 18:29

【摘要】：空气静压电主轴结合高速电主轴和气体轴承的特点,以其精度高、转速高、磨损小、清洁度高和运行平稳等优点,在精密和超精密数控加工机床中获得广泛应用。随着气体轴承理论研究和应用的发展,单纯研究气体轴承特性已经无法满足实际设计需求,应该充分考虑气体轴承和转子之间的相互耦合作用,尤其是转子运动对气体轴承-转子系统的影响。本文以空气静压电主轴为研究对象,对气体轴承-转子系统的流固耦合作用、转子不同倾斜状态对径向气体轴承承载力和刚度的影响进行研究,同时对电主轴进行动、静态加载实验,测试电主轴的动静态性能。通过建立气体轴承-转子系统的仿真模型,运用数值分析方法进行双向流固耦合仿真,分析了径向、轴向加载下气体轴承-转子系统的承载特性。研究结果表明,流固耦合过程中转子位移、轴承气膜压力和承载力都是动态变化过程;系统稳定平衡后,转子呈现倾斜状态,气膜厚度和压力分布不均匀;供气压力一定时,转子转速增高使转子径向位移有增大趋势,提高供气压力转子径向位移减小,可降低转子与径向轴承的碰撞几率。建立转子倾斜状态下径向气体轴承仿真模型,运用CFD方法对其进行流场仿真,分析了径向气体轴承在不同转子倾斜角、转速、气膜偏心率状态下,承载力和刚度的变化规律。研究结果表明,转子静止时大偏心率下的气膜承载力随倾斜角增大而减小;转子不同转速下气膜承载力随着倾斜角增大而增大,体现了动压效应对不均匀膜厚的影响;转子不同转速下气膜刚度随倾斜角增大而增大。搭建空气静压电主轴性能测试实验平台,采用非接触加载方式对空气静压电主轴进行动、静态径向加载实验,获得不同负载、供气压力、转速等工况下的转子轴端位移,并与流固耦合仿真数据进行对比分析,二者变化趋势一致,验证了流固耦合仿真的有效性。
[Abstract]:Combined with the characteristics of high speed motorized spindle and gas bearing, air hydrostatic spindle has been widely used in precision and ultra-precision NC machine tools for its advantages of high precision, high speed, low wear, high cleanliness and smooth operation. With the development of gas bearing theory and application, the study of gas bearing characteristics has been unable to meet the actual design requirements, and the coupling between gas bearing and rotor should be fully considered. Especially the effect of rotor motion on gas bearing-rotor system. In this paper, the hydrostatic motorized spindle is taken as the research object, the fluid-solid coupling effect of the gas bearing-rotor system and the influence of the rotor's different tilting state on the bearing capacity and stiffness of the radial gas bearing are studied. At the same time, the motorized spindle is moved. The static and static performance of the motorized spindle was tested by static loading experiment. By establishing the simulation model of gas bearing-rotor system and using the numerical analysis method to simulate the bidirectional fluid-solid coupling, the bearing characteristics of the gas bearing-rotor system under radial and axial loading are analyzed. The results show that the rotor displacement, bearing film pressure and bearing capacity change dynamically during the fluid-solid coupling process; after the system is stabilized and balanced, the rotor is inclined, the film thickness and pressure distribution is uneven, and the gas supply pressure is constant. With the increase of rotor speed, the radial displacement of the rotor increases and the radial displacement of the rotor decreases with the increase of the air supply pressure, which can reduce the collision probability between the rotor and the radial bearing. The simulation model of radial gas bearing in tilted rotor is established. The flow field of radial gas bearing is simulated by CFD method. The variation of bearing capacity and stiffness under different rotor inclination angle, rotating speed and eccentricity of gas film is analyzed. The results show that the bearing capacity of the film decreases with the increase of the inclined angle when the rotor is at rest, and the bearing capacity of the film increases with the increase of the inclined angle at different rotational speeds, which reflects the effect of dynamic pressure on the non-uniform film thickness. The film stiffness increases with the increase of tilt angle at different rotor speeds. An experimental platform for testing the performance of aerostatic motorized spindle was built. The dynamic and static radial loading experiments were carried out on the aerostatic motorized spindle with non-contact loading mode, and the rotor shaft end displacement was obtained under different load, air supply pressure, rotating speed and other working conditions. Compared with the fluid-solid coupling simulation data, the trend of the two changes is the same, which verifies the effectiveness of the fluid-solid coupling simulation.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG659

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