线接触弹性流体动力润滑的供油条件分析

Analysis of Oil Supply Conditions for Elastohydrodynamic Lubrication in Line Contacts

以油膜起始位置为参数,求出了等温线接触弹性流体动力润滑问题的完全数值解.通过流量分析,建立了有效供油膜厚与油膜起始位置之间的关系.结果表明,弹性流体动力润滑的供油方式可划分为过量供油、适量供油和乏油3种类型.在过量供油条件下大部分润滑油不能进入接触区,因而并不能改善润滑状态.在适量供油条件下所有润滑油均可通过接触区并能够获得最大的油膜厚度.在乏油条件下所有的润滑油也均可以通过接触区,而油膜厚度则完全由供油量确定.同时,数值结果也指出,只要运动表面存有数量级为1μm厚的一层油液就足以满足适量供油条件而得到最佳的润滑效果.

Taking the start position of the lubricating film as an input parameter, full numerical solution of the elastohydrodynamic lubrication （EHL） in line contacts was obtained under isothermal condition. Through an analysis of the flux of lubricant, the relationship between the effective thickness of the supplied oil layer and the start position of the lubricating film was established. There exist three types of oil supply conditions for EHL films, i.e. , the over-flooded, fully flooded, and starved conditions. Under the over-flooded condition most lubricant cannot enter the contact, so that such a condition is no benefit to EHL. Under the fully flooded condition, however, all available oil can pass through the contact and results in the largest film thickness. Under the starved condition, all available oil can also pass through the contact, yet the film thickness depends completely upon the quantity of the supplied oil. Numerical solutions indicate that, a layer of the available oil on the moving surface with a thickness of the order of magnitude of 1 1μm is enough to satisty the fully flooded condition of an EHL contact, and it results in the optimum lubricating performance.