Turbocharger drive and planet bearing therefor

A planet bearing and gear assembly for the carrier of a speed increasing planetary gear train for driving a diesel engine turbocharger or the like includes an enlarged diameter gear bore and associated bearing outer diameter for lightening the gear and increasing the bearing area to at least 50 percent and preferably more than 65 percent greater than those of the bearing inner wall and the outer diameter of an associated support pin. Self-cleaning of unfiltered dirt particles in the engine lubricating oil is provided by dirt expulsion passages formed by flats at the edges of an oil supply groove in the planet bearing while operation with entrained dirt particles capable of passing through the engine lubricating oil filters is improved by increased oil film thickness resulting from reduced bearing loads due to reduction of mass of the planet gears and increased bearing surface. Circumferential oil grooves in the inner surface help cool the bearing prior to delivery to an oil supply groove which is configured with a flat floor toward one end adjacent oil supply holes and an arcuate floor on the other end to improve manufacturing accuracy and convenience.