Fine Tuning Roller Profile Increases Bearing Life

Cooper has fine tuned the roller profile on its most popular size of bearings. The theoretical optimum logarithmic profile roller gives a projected improvement in L10 life of 25% over profiles used previously. The logarithimic profile can be proportioned to give sufficient depth of relief to be effective at high peak loads and make better use of the length of the roller at light loads compared with conventional profiles. In the harsh operating environment of the typical bearing, small changes can make big improvements. Consider, for instance, the surface of the rolling elements. The profiling of rollers to avoid stress concentrations (end effects) at the ends of rollers has been standard practice for many years, but the geometry of the profile and the resultant effect on the life of the bearing can vary. Without a suitable profile on the rollers, premature bearing failure would occur from spalling initiated towards the edges of the raceways.