Slip Characteristics in Cylindrical Roller Bearings-Part II: Influence of Cage Type on Rolling Element Slip

The rolling element slip of an NU215 cylindrical roller bearing fitted with four cage types was studied under various operating conditions. In comparison, a specially designed full complement bearing with the same principal dimensions was also tested as an alternative. Unlike the load zone width, the acceleration zone width was found to be independent of the applied radial force, and when the dynamic force was introduced, the load zone slip was increased. For the full complement bearing, the rollers were found to stall completely in the unloaded zone resulting in a 100% roller slip at the beginning of the acceleration zone. This behavior was also confirmed by using a high-speed camera. For the tested cages, the roller-guidance under a vertically radial force pointing downwards resulted in a secondary load zone where the weight of the cage forces the rollers to contact the rotating inner ring once more leading to decreased overall slip values compared to outer ring guidance while the polyamide introduces higher cage/roller interactions leading to higher load zone slip as well as a wider load zone.