考虑加工误差的油膜轴承动态性能研究

发布时间：2018-09-10 14:11

【摘要】：课题来源于国家自然科学基金项目“新型高性能油膜轴承节流机理研究(51075409)”。随着旋转设备向着高速、重载、精密化方向发展,设备的精度要求及运行环境对作为重要基础支承部件的油膜轴承的性能提出了更高的要求。油膜轴承为提高其性能,轴承与轴颈之间必须采用较小的配合间隙,这使轴承制造过程中产生的误差与轴承的油膜厚度处于同一个数量级上,显著影响油膜轴承的性能。通过不断提高轴承加工精度来获得高性能油膜轴承的途径会使生产成本增加,制造周期增长,产品合格率低。为此,本文在已有研究基础上,引入加工误差模型,建立了考虑加工误差的油膜轴承润滑理论模型。同时,为了降低加工误差的影响,将传统节流器与伺服可控节流相结合提出一种伺服混合可控节流油膜轴承,引入基于遗传算法优化PID控制器参数的伺服主动控制技术,对油腔的进油液阻进行调节从而控制油腔中的油压以提高轴承的性能。通过建立加工误差对轴承性能影响的累积效应数学模型,对比分析考虑加工误差的毛细管节流油膜轴承与混合节流油膜轴承的动态特性,研究加工误差因素对轴承的性能影响以及对主轴的位置精度、回转精度的作用规律,以寻求一种既能降低制造成本,又能提高轴承性能的方法,为轴承的性能分析和设计提供依据。论文的主要工作及成果如下:①在传统油膜轴承基本润滑理论基础上,考虑加工误差因素对油膜轴承的影响,建立加工过程中产生的尺寸误差、形状误差表达式,建立加工误差对轴承性能影响的累积效应数学模型。以此重构油膜间隙函数、雷诺方程、流量连续性方程,建立考虑加工误差的油膜轴承动态特性分析模型。②构建了混合节流油膜轴承系统。建立混合节流油膜轴承控制系统及PID控制器参数优化模型。根据流体润滑和承载机理推导油膜轴承油腔内、封油面上的油膜力以及主轴动力学方程,建立混合节流油膜轴承性能分析的数学模型。采用遗传算法对轴承控制系统的PID控制器参数进行优化。将加工误差的数学模型进入到混合节流油膜轴承系统中,重构轴承性能分析的数学模型。③对比分析不考虑加工误差影响情况下,工况条件变化(载荷、转速、粘度)对混合节流油膜轴承与毛细管节流油膜轴承的承载能力、油膜刚度、最小油膜厚度、流量的影响规律。④以伺服混合节流与毛细管节流油膜为研究对象,对比分析了尺寸误差、形状误差对油膜轴承承载能力、油膜刚度、对象油膜厚度、流量、油膜力分布的影响;研究加工误差对主轴位置精度、回转精度的影响规律。⑤设计研制了实验台,进行了轴承误差数据的测量和运动误差的分离。通过对比研究仿真与实验结果验证了考虑加工误差因素影响的油膜轴承的模型和分析方法的有效性和一致性。本文将加工误差引入到油膜轴承性能分析中,丰富、深化了油膜轴承润滑理论,提出的混合节流油膜轴承能较好地抑制和减小加工误差对轴承性能的影响。论文研究成果对于开发适用于中低速、重载、高精度油膜轴承提供了重要的参考价值及理论依据。
[Abstract]:With the development of rotating equipment toward high speed, heavy load and precision, the precision requirements and operating environment of the equipment put forward higher requirements for the performance of oil film bearing as an important supporting component. In order to improve the performance of the bearing, a small clearance must be adopted between the bearing and journal, which makes the errors produced in the manufacturing process of the bearing in the same order of magnitude as the thickness of the oil film of the bearing and significantly affects the performance of the oil film bearing. In order to reduce the influence of machining error, a servo hybrid throttling oil film with controllable throttling is proposed, which combines traditional throttle with servo throttling to reduce the influence of machining error. In order to improve the performance of bearings, a servo active control technique based on genetic algorithm is introduced to optimize the parameters of PID controller. The hydraulic resistance of oil cavity is adjusted to control the oil pressure in the oil cavity to improve the performance of bearings. The dynamic characteristics of film bearing and hybrid throttle oil film bearing are studied. The influence of machining error on bearing performance and the effect of machining error on position accuracy and rotation accuracy of spindle are studied. A method which can not only reduce manufacturing cost but also improve bearing performance is sought to provide basis for bearing performance analysis and design. The results are as follows: 1. Based on the basic lubrication theory of traditional oil film bearings, considering the influence of machining error factors on oil film bearings, the expressions of dimension error and shape error are established, and the cumulative effect mathematical model of machining error on bearing performance is established. (2) Hybrid throttle oil film bearing system is constructed. Hybrid throttle oil film bearing control system and PID controller parameter optimization model are established. Oil film force and spindle in oil film bearing cavity, oil cover and spindle are deduced according to fluid lubrication and loading mechanism. A mathematical model for the performance analysis of hybrid throttle film bearings is established. The parameters of the PID controller of the bearing control system are optimized by genetic algorithm. The influence of operating conditions (load, rotational speed, viscosity) on the bearing capacity, oil film stiffness, minimum oil film thickness and flow rate of hybrid throttle oil film bearing and capillary throttle oil film bearing under loud condition is studied. The influence of machining error on spindle position accuracy and rotation accuracy is studied. _The experimental platform is designed and developed, and the measurement of bearing error data and the separation of motion error are carried out. The simulation and experimental results verify that the machining error is considered. In this paper, machining errors are introduced into the performance analysis of oil film bearings to enrich and deepen the lubrication theory of oil film bearings. Hybrid throttling oil film bearings can better restrain and reduce the influence of machining errors on bearing performance. It provides important reference value and theoretical basis for developing medium and low speed, heavy load and high precision oil film bearings.
【学位授予单位】：重庆大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：TH133.3

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