旋转轴唇形油封泵汲效应

基于旋转轴唇形油封的微观和宏观泵汲原理,应用流体动力学一维雷诺方程及油膜厚度表达式,假设唇口接触压力分布近似为三角形推导出泵汲率方程,计算分析了安装相关参数(接触宽度、抱轴力)、结构参数(油侧唇角、空气侧唇角)及运行参数(转速)等对泵汲率和密封性能的影响.结果表明,优化前和优化后2种油封模型的泵汲率均大于0,满足密封要求.抱轴力一定时,接触宽度增加,泵汲率增加;接触宽度不变时,随抱轴力的增加,油封唇口摩擦扭矩增大,泵汲率逐渐变小,但变化幅度不大.空气侧唇角不变时,随着油侧唇角增加,2种油封的泵汲率均显著增加;油侧唇角一定时,空气侧唇角增加,泵汲率逐渐减小.随着转速增大,唇口动压效应增强,泵汲率随之增大.2种油封相比较,优化后油封明显具有更好的泵汲效应和密封性能.

Pumping effect for rotary lip seal

Based on the microcosmic and macroscopic pumping principle of the rotary shaft lip seal,using the one-dimensional Reynolds equation of hydrodynamics and the oil film thickness expression,the pumping rate equation is deduced on the assumption that the contact pressure distribution of seal lip would be approximately triangular.The influence of installation parameters(contact width,axial force),structure parameters(oil side lip angle,air side lip angle)and operation parameters(rotational speed)on the pumping rate and sealing performance is calculated and analyzed.The results show that the pumping rate of the two oil seal models before and after optimization is greater than zero to meet the sealing requirement.When the axial force is constant,the pumping rate increases with the increase of contact width;when the contact width is unchanged,with the increase of the axial force,the friction torque of oil seal lip increases,the pumping rate gradually decreases and the amplitude of variation is small.For two rotary lip seal models,when the air side lip angle remains unchanged,the pumping rate significantly increases with the increase of oil side lip angle;when the oil lip angle is constant,the pumping rate gradually decreases as the air side lip angle increases.As the rotating speed increases,the dynamic pressure effect of oil seal lip increases,and the pumping rate increases.Compared with the two kinds of oil seals,the optimized oil seal has better pumping effect and sealing performance.