[208] Advanced debris monitoring for next-generation bearing materials and technologies in high-power aircraft powerplant and rotorcraft transmissions
J Zielinski and S Greenfield
Eaton Aerospace, UK
Debris monitoring has been used to detect the presence of wear particles in lubricating oils, transferred from the oil-wetted surfaces of gears and bearings under mechanical distress, for many years. Online debris monitoring is preferred as it eliminates the need for routine inspections and pre-empts the potential catastrophic failure, should it advance faster than the scheduled inspection interval. With the introduction of hybrid bearings growing (steel races and ceramic rolling elements), there is currently an urgent and unmet need for the online detection of failure related to non-metallic debris in the lubricating fluid. The aerospace industry has delayed deployment of hybrid bearings because there was no viable technology that could detect non-metallic debris online. Until now, filter blockage was the only detection method and this is considered far too little too late. Hybrid bearings have many important features that will improve engine efficiencies, such as 40% lower weight, higher DN speeds (bearing diameter time operating speed) and higher-temperature operation and lower centrifugal force (due to lighter weight), so they can operate at higher speeds. Gears, however, remain steel-based and are detectable by online quantitative debris monitors. Combining the two technologies gives the solution presented in this paper for highly reliable metallic and non-metallic oil-borne debris condition monitors.
