Dynamic Capacity Rating of Roller Bearings

An engineering discussion of the Lundberg-Palmgren theory of contact fatigue and considerations made therein for the specific case of fatigue life prediction for roller bearings is presented. First, attention is directed toward the selection of the endurance parameter and elaboration is made upon the mechanism by which surface failure is propogated; the concepts of material strength dispersion and stressed volume; and of the Palmgren treatment leading to the concept of dynamic capacity for a contact, with subsequent extension to the cases of rotating and non-rotating raceways and bearing life prediction. Next, AFBMA and ISO standards concerning the dynamic capacity ratings of roller bearings are considered; major assumptions important to the standards development from the fatigue theory, and crucial to the understanding of inherent limitations, are illuminated. Finally, an example is presented whereby life predictions of a roller bearing application, made using exact and standards methods, are contrasted.