周期性载荷下润滑剂回填效应试验观察

Observation of Lubricant Replenishment under Cyclic Loading

采用球-盘单点接触光干涉润滑油膜测量仪,试验观察了周期性载荷变化对润滑剂回填及润滑状态的影响。结果表明,当加载/卸载过程滚动体的运行距离大于滚道周长时,滚动体瞬时接触半径与已形成的滚道半径不一致,导致加载过程润滑状态整体优于卸载过程;周期性载荷变化下润滑状态优于恒定载荷下的润滑状态,毛细力和表面张力作用下的润滑剂回填是其诱因;不同载荷下接触半径变化梯度的增加有利于润滑剂的回填,使得卸载末期润滑油膜反弹。

Using the ball-on-disc single contact optical thin film measurement apparatus,the lubricant replenishment and lubrication states under cyclic loading are observed.The results show that if the rolling element running distance in the loading/unloading process is larger than the circumference of the track,the instant contact width will be inconstant with the existing track width.In consequence,the lubrication state in the loading process is better to some extent than that of the unloading case.Moreover,the lubrication state under cyclic loading is superior to the steady case,mainly due to the lubricant replenishment under capillary and surface tension effects.The lubricant replenishment can be improved due to an increase in the contact radius variation gradient,causing the film thickness to rebound at the end of unloading.