Towards Bearings Prognostics Based on Oil Debris

Rolling element bearings are widely used in many mechanical systems and affect their safe operation and reliability. The use of an integral Oil Debris Monitoring (ODM) sensor in the lubrication system allows continuous monitoring of chips and particles originating from an evolving failure in the mechanical system oil wetted components. This paper examines the use of the mass loss from an ODM sensor as a health indicator to assess damage severity and Remaining Useful life (RUL) of a rolling element bearing faulted in one of its raceways. A series of experiments were performed on a test rig using angular contact ball bearings subjected to high rotational speed and loads to study the propagation of a spall in the bearing raceway. A spall size estimation model that uses the mass loss from the ODM and known bearing characteristics was developed and showed good results. Based on tests results, a concept has been suggested to estimate bearing spall size and RUL to a critical spall size.