US Patent 7758251 Drawn cup needle roller bearing

A drawn cup needle roller bearing comprises a drawn cup having flanges formed by a bending process at both ends, rollers arranged along the inner diameter surface of the drawn cup, and a no-metal cored seal incorporated on the inner diameter side of the drawn cup. The drawn cup in which the rollers are incorporated is heat treated and the no-metal cored seal is elastically deformed and incorporated inside the drawn cup past the flange. Here, the roller has a nitrogen-enriched layer on its surface layer, and the nitrogen-enriched layer contains not less than 20% by volume of retained austenite.