Direct Swapping Si3N4 for Steel Reduces Bearing Load Si3N4 Balls Increase Fatigue Stresses in Steel Raceways Reduced Load Capability is due to Steel Limitations
Increased # Balls Reduces Stress, Stiffens Bearing Machine Tool Bearing Operate Substantially Below Max. Load Conditions Hybrid Machine Tool Bearings Rarely Fail from Ball Related Problems
A frequently asked question regarding hybrid bearing performance is the load capability which affects the L10 Life Calculation of a hybrid bearing. This is an important issue and has been given significant attention over the past several years. Silicon nitride ball is much stiffer than a steel ball and thus, the contact patch on the raceway is much smaller. For any given load, this means that the stress in the raceway at the contact patch is increased and, "theoretically," the L10life will be reduced in a hybrid bearing. Indeed applications that require bearings to perform at nearn maximum load levels (when bearings, for example) demonstrate lower life characteristics when a hybrid bearing is substituted for a steel bearing because the fail from fatigue. Machine tool bearings, however, rarely approach maximum load conditions making the hybrid bearing a practical substitude for a steel bearing in any application. Further, bearing designers can adjust the raceway curvatures and the number of balls in a hybrid bearing to improve the load carrying capability of the bearing.