Study on starved HEL for developing lubrication method of rolling bearing with minute amount of lubricant

采用Elrod算法对中心油膜厚度、最小油膜厚度、入口弯月面长度和侧弯月面长度进行了数值分析，得到了它们与入口油膜厚度的关系式。最小油膜厚度与中心油膜厚度的比值随着饥饿状态的进行而趋于均匀。为了验证推导的公式，并研究滚珠连续通过对实际滚珠轴承中出现的饥饿油膜厚度的影响，研制了干涉法饥饿油膜厚度测量装置。用干涉法测量了玻璃圆盘上同一圆周轨迹上三个顺序排列的滚珠的各饥饿弹流润滑膜厚度的减少量。具有均匀分布的初始入口膜厚度由放置在第一球前面的辊产生。玻璃盘上的润滑剂膜穿过球和盘之间的结合部，然后通过粘附球表面而部分地回流到球的同一入口。因此，中心膜厚度由玻璃盘上的膜厚度和流入其入口的球表面上的膜厚度的一半控制。同时求解中心膜厚关系，所得中心膜厚计算公式和Hamrock-Dowson中心膜厚计算公式与干涉法测量结果一致，误差小于10%。此外，连续通过时油膜厚度减小的预测值与实测值吻合较好，在完全淹没条件下，当入口油膜厚度与中心油膜厚度近似相等时，润滑剂边带对弯月面长度的影响显现出来。在这种情况下，侧弯月面长度变得与计算结果相差很大。然而，这种差异仅对中心膜厚度有影响。

Regression formulae which give central film thickness, minimum film thickness and both inlet meniscus and side meniscus lengths as a function of inlet film thickness are derived by a numerical analysis incorporating Elrod algorithm, respectively. A ratio of the minimum film thickness to central film thickness becomes uniform value as starvation state proceeds.A measurement apparatus for starved film thickness with interferometry has been developed to verify the derived formulae and to investigate effect of sequential ball passing on the starved EHL film thickness, which appears in practical ball bearings. That effect is investigated by measuring the reduction of the each starved EHL film thickness of the three sequentially arranged balls in the same circumferencial track on a glass disk with interferometry. Initial inlet film thickness with uniform distribution is generated by a roller which is placed in front of the first ball. This lubricant film on the glass disk passes through the conjunction between ball and disk and, then, partially re-flows an same inlet of the ball by adhering its ball surface. Therefore, central film thickness is controlled with sum of the film thickness on the glass disk and half of the film thickness on the ball surface flowing in its inlet. Central film thickness by solving simultaneously this relationship, the derived formulae and Hamrock-Dowson formula for central film thickness agrees with interferometry measurement result with errors less than 10%. In addition, the predicted reduction in film thickness by sequentially passing also agrees with measurement result.Influence of side band of lubricant on the meniscus length appears if the inlet film thickness is approximately equal to central film thickness in a fully flooded condition. In this case, the side meniscus length becomes to considerably differ from calculating result. However, this difference has merely influence on the central film thickness.