Film Characteristics of Grease in Point Contact under Micro-Swaying Motion

Transient thin-film lubrication of the grease occurs in many machine elements including bearings, gears and cams. It also occurs in rolling-element bearings at the start or stop of motion. Thus the lubricant supply and film formation are important in ensuring the successful operation of a bearing. This paper uses experiment to study the behavior of grease films in swaying motion. The technique of Relative Optical Interference Intensity is used to measure the film thickness and the film profile through analysing the interference images which are captured at a rate of 60 times per second. The lubrication state is monitored during accelerated and decelerated motion. The experiment results show that the grease lubrication in swaying motion is a complex problem. The minimum film thickness does not occur at the theory position, but with a certain time delay which is relative to the change of speed and the rate of change motion direction.