唇形油封密封性能及其轴表面织构效应的研究

发布时间：2018-05-30 10:37

本文选题：唇形油封 + 静态接触特性　；参考：《浙江工业大学》2016年博士论文

【摘要】：唇形油封由于结构简单、性能可靠、安装方便和价格低廉等优点,广泛应用于机械旋转轴的密封场合,其功能是将油腔和外界环境相隔离,起到对内封油、对外防尘的作用,是目前最常用的密封件之一。但是,由于油封密封机理复杂,影响密封性能的因素繁多,人们对油封产品的设计很大程度上仍然依靠经验和试验完成。随着现代机械工况参数向着高温、高速和高压等方向发展,唇形油封面临着零泄漏、低摩擦和长寿命等更加苛刻的性能要求,而传统的油封设计方法和产品显然难以满足上述需求,因此,开展油封密封性能的理论和实验研究具有重要的应用价值。基于此,本文采用理论分析、数值模拟和实验研究相结合的方法,开展油封静态接触特性、密封性能,以及轴表面织构流体效应的研究,主要研究内容和取得的成果如下:(1)分析了唇形油封的结构和安装特点,建立了油封的二维轴对称有限元模型,获得了安装过盈量、橡胶弹性模量、油封内径参数和材料本构模型等因素对油封唇口接触压力、接触宽度和径向力的影响规律,计算得到的油封唇口接触应力和变形分布符合实际工作状态,径向力与工程计算值吻合较好,研究成果有助于油封结构的优化,并可进一步为油封密封性能理论模型的研究提供基础数据;(2)分析了油封唇口的润滑与密封机理,提出了油封稳态工作润滑与密封的数学模型,考虑了唇口密封区液膜空化现象和表面橡胶弹性变形的影响,建立了遵循质量守恒的JFO空化边界条件的润滑力学控制方程,并采用流线迎风有限元法求解控制方程,计算了等膜厚和等闭合力下油封的密封性能,获得了油封操作参数、表面形貌结构参数和材料参数对泵送率、承载力和摩擦扭矩等密封性能参数的影响规律;(3)为提升唇形油封的密封性能,提出了轴表面设置方向性微织构的手段,采用数值方法研究了菱形、椭圆形、矩形和等腰三角形等4种轴表面微凹坑/凸体织构的流体动压效应,分析了轴表面织构的形式、几何参数对油封密封性能的影响,获得了相同条件下矩形微织构优于其他3种织构,微凸体织构优于微凹坑织构的作用规律;(4)由于轴表面微凹坑织构较微凸体容易加工实现,实验对比研究了菱形、椭圆形、矩形和等腰三角形等微凹坑织构类型对丁腈橡胶油封摩擦扭矩的影响,以及实验研究了矩形微凹坑织构方向性角度、面积密度和深度对油封摩擦扭矩的作用规律,并和数值模拟结果进行了对比,得到了初步的验证。论文成果完善了油封的设计理论与方法,对于提升油封的密封性能和使用寿命具有重要的理论价值和实际意义。
[Abstract]:Because of the advantages of simple structure, reliable performance, convenient installation and low price, the lip oil seal is widely used in the sealing occasions of the mechanical rotary shaft. Its function is to isolate the oil chamber from the external environment and play the role of sealing the oil inside and preventing dust from the outside. Is one of the most commonly used seals. However, because of the complexity of the sealing mechanism and the variety of factors affecting the seal performance, the design of oil seal products still depends on experience and test to a great extent. With the development of modern mechanical parameters towards high temperature, high speed and high pressure, the lip seal is faced with more stringent performance requirements such as zero leakage, low friction and long life. However, the traditional oil seal design methods and products are obviously difficult to meet the above requirements. Therefore, it is of great value to carry out the theoretical and experimental research on the seal performance of oil seal. Based on this, this paper studies the static contact characteristics, sealing performance and axial surface texture fluid effect of oil seal by means of theoretical analysis, numerical simulation and experimental study. The main research contents and results obtained are as follows: (1) the structure and installation characteristics of the lip seal are analyzed, the two-dimensional axisymmetric finite element model of the oil seal is established, and the installation interference and rubber elastic modulus are obtained. The influence of parameters of inner diameter and material constitutive model on the contact pressure, contact width and radial force of oil seal lip is studied. The calculated distribution of contact stress and deformation of oil seal lip is in accordance with the actual working state. The radial force is in good agreement with the engineering calculation value, and the research results are helpful to the optimization of the oil seal structure, and can provide the basic data for the study of the theoretical model of the seal performance.) the lubrication and sealing mechanism of the oil seal lip are analyzed. A mathematical model of the steady working lubrication and sealing of oil seal is presented. Considering the cavitation phenomenon of liquid film and the elastic deformation of rubber surface in the lip seal region, the governing equation of lubrication mechanics is established, which follows the JFO cavitation boundary condition of mass conservation. The control equation is solved by streamline upwind finite element method, and the sealing performance of oil seal under equal film thickness and equal closing force is calculated. The operating parameters, surface structure parameters and material parameters of oil seal are obtained. In order to improve the seal performance of lip oil seal, a method of setting directional microtexture on the shaft surface is proposed, and the rhombus and oval shape are studied by numerical method. The hydrodynamic pressure effect of four kinds of axial surface microcrater / convex texture, such as rectangle and isosceles triangle, is analyzed. The effects of the form of axial surface texture and geometric parameters on the sealing performance of oil seal are analyzed. Under the same condition, rectangular microtexture is superior to other three kinds of texture, and microconvex texture is superior to microconcave texture. The effect of texture types such as rectangle and isosceles triangle on friction torque of nitrile rubber oil seal was studied. The effect of orientation angle, area density and depth of rectangular microcrater texture on friction torque of oil seal was studied experimentally. The results are compared with the numerical simulation results, and the results are preliminarily verified. The paper has perfected the design theory and method of oil seal, which has important theoretical value and practical significance for improving seal performance and service life of oil seal.
【学位授予单位】：浙江工业大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TH136

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