Effect of lubrication conditions on the acoustic emission behavior of thrust rolling bearings

Bearings are important supporting components for rotating machinery, but their on-line lubrication status during operation is difficult to be detected. This paper aims to develop a method for lubrication condition monitoring of rolling bearings using an acoustic emission (AE) technique. To this end, thrust rolling bearing tests were conducted. It was found that lubricant can influence AE signal fluctuation, and that the variation of lubricant viscosity changes the distribution of AE signal in the amplitude-energy coordinate system. The investigation concluded that a properly formulated AE amplitude and energy can provide a useful message for justifying the lubrication status of rolling bearings at operation.