Development of long life rolling bearings for use in the extreme conditions

As the service conditions of automobiles and industrial-machines are becoming more extreme in recent years, higher bearing performance has been required for those applications. Especially, a demand for maintenance-free bearings is really high, that is a demand for the extension of bearing fife has been increasing. To satisfy those customers' demands, various measures as to materials and heat treatment have taken, those of which are KE bearings developed for automobiles and KUJ7 steel for semi-high temperature bearings. The characteristics in material and heat treatment necessary to extend bearing life and the direction of measures to each factor are described, then the characteristics of KE bearings and KUJ7 steel are also described.