Advances in high-speed rolling-element bearings

Advances in airbreathingturbojetjet engineshave dictated that bearing materialsand lubricantsoperate at higher temperatures,higher speeds, and higher loads.Projectionsin the late 1950's indicatedthat the trends in engine operatingspeeds would dictate ball and roller bearingsoperating at speeds to three million DN and temperaturesto 590 K (600" F).Helicopter transmissiondevelopmentin the 1960's suggestedthe need for tapered roller _ bearingsto operate at speeds to two million DN.NASA research in collabora-N Lion with United States industrybetween 1960 and 1980 achievedthese ,e-4 ' state-of-the-art advances.The NASA programwas both experimentaland Ld analyticwith the analyticeffort verifiedby experiment.The reportedwork is a summaryof aircraftengine and transmissionrolling-element bearing stateof-the-artwith emphasison NASA contributions.