零卷吸预跑合对一类反常弹流油膜的影响

Influence of Zero-entrainment-velocity Pre-running on EHL Films with an Inlet Dimple

在极低速纯滑动的光弹流实验中,采用高粘度聚丁烯润滑剂形成的弹流油膜会在入口区出现凹陷,该反常的入口凹陷与极限剪切应力/界面滑移有关。针对盘纯滑和球纯滑2种不同的运动条件进行了油膜形状的测量,分析了零卷吸预跑合对油膜形状的影响。结果表明,一般地,纯玻璃盘滑动和纯钢球滑动产生的此类反常的油膜形状并不相同;当对弹流接触副采用零卷吸预跑合处理(即钢球和玻璃盘在接触区以大小相同方向相反的速度运动)之后,纯玻璃盘滑动形成的油膜形状有较大变化,油膜厚度增加,入口的楔形斜度下降,此时纯玻璃盘滑动和纯钢球滑动产生的油膜形状差别减小,甚至相同。

In optical EHL experiments under pure sliding at very low speeds, polybutene lubricants can produce EHL films with an inlet dimple, which is correlated to the limiting shear stress/boundary slippage. The film shapes under pure disc sliding and pure steel ball sliding were measured, the influence of zero-entrainment-velocityero-entrainment-velocity （ZEV） pre-running,in which the glass disc and the steel ball runs at speeds of the same magnitude but opposite direc- tions, on the film shapes was analyzed. The experimental results show that generally the pure disc sliding and the steel ball sliding produce inlet dimple films of different shapes. However, when an ZEV pre-running was applied, the film shapes under pure disc sliding change significantly, the film thickness increases and the slope of the inlet wedge decreases. The difference between the films under pure disc sliding and the ball sliding becomes small, and even the same film shapes are obtained.