滚道表面供油层分布规律及轴承补充供油机制研究

The high-performance rolling bearing is one of the common bottlenecks that restrict the performance improvement of high-speed railway, aero-engine, and other major equipment. Improving lubrication performance is one of the most effective way to improve the precision and service life of rolling bearings. The elasto-hydrodynamic lubrication (EHL) theory, as the lubrication mechanism of rolling bearings, mainly focuses on the characteristics of film thickness inside the rolling element/raceway contact area. In contrast, few studies have involved either the distribution of supply oil layer outside the contact zone or the replenishment of oil near the inlet zone which also have a significant influence on the lubrication performance. This project aims at the fundamental research on the distribution of supply oil layer on the free raceway surface and the mechanism of replenishment in rolling bearings based on experiment and theoretical modeling. The main contents include: (1) To develop a high-precision ratio-metric fluorescence technique for film thickness measurement and to establish an in-situ measuring system for the distribution of supply oil layer on free raceway surface. (2) To develop an oil flow model on free raceway surface with the consideration of the effects of multiple factors including centrifugal force, surface tension, periodic loading and bearing geometric design. (3) To reveal the mechanism of both the oil layer transportation and distribution on the rolling bearing’s raceway surfaces. (4) To explore the oil replenishment mechanism in rolling bearings. This project is an important bridge between lubrication foundation and bearing design theory which not only has important academic significance enriching the lubrication theory, but also plays an important guiding role in bearing design.

高性能滚动轴承是制约高铁、航空发动机等重大装备性能提升的共性瓶颈问题之一，而改进润滑性能是提升轴承性能的重要措施。作为滚动轴承润滑机理的弹流润滑理论研究主要集中在接触区内成膜特性，鲜有对润滑性能有重要影响的接触区外润滑油分布规律和补充供油机制的研究。本项目采用实验研究与理论建模相结合的方法，针对滚道表面供油层分布规律与补充供油机制展开研究，主要内容包括：(1)发展高精度双重标定荧光方法，建立滚道表面供油层分布在线测量系统，实现微米级/亚微米级旋转自由表面油层原位动态测量；(2)构建考虑离心力、表面张力、周期性加载、轴承结构参数等多因素综合的滚道表面供油层流动模型；(3)系统研究滚道表面供油层输运与分布规律和影响机制；(4)揭示滚动轴承补充供油机制。本项目是润滑基础理论与轴承设计理论的重要桥梁，将为轴承润滑研究提供新的实验平台、构建较完备的理论分析模型；研究成果将为滚动轴承设计提供理论支持。

高性能滚动轴承是制约高铁、航空发动机等重大装备性能提升的共性瓶颈问题之一，而改进润滑性能是提升轴承性能的重要措施。本项目重点关注滚道表面接触区外润滑油分布规律和补充供油机制的研究，是滚动轴承润滑机理重要理论补充。通过实验研究与理论建模相结合的方法，主要开展了以下工作：(1) 发展了基于荧光方法的自由表面油层厚度动态大量程测量方法，建立滚道表面供油层分布在线测量系统，实现了4.4~700微米范围内油层厚度原位测量；(2) 实验研究了滚动轴承钢球-外圈接触区的润滑成膜规律，分析了热效应和乏油对膜厚下降的影响；(3) 实验研究了滚道表面供油层在不同速度、供油条件和保持架结构下的输运行为与分布规律；(4) 建立了滚动轴承内润滑油输运与界面流动模型，发现毛细数为轴承内润滑油分布状态变化的关键判据。(5) 揭示了不同速度条件下滚动轴承内的补充供油机制。本项目的成功实施为轴承润滑研究提供了新的实验平台和试验方法，构建了较完备的理论分析模型；研究成果可为滚动轴承设计提供理论支持。