Influence of Residual Stresses Introduced by Manufacturing Processes on Bearing Endurance Time

By enhancing surface properties and by reducing weight and size of machine elements, future trends in resource efficiency for machines can be fulfilled. Rolling element bearings are widely used machine elements. By improving their boundary zone properties, there is a potential to extend maintenance-free operating periods, postpone replacements or increase the lifespan of the complete system. The aim is to set favorable boundary zone properties by enhancing the residual stress state within the manufacturing process. For this, the processes hard turning and deep rolling were investigated. The influence of the initial residual stress state on fatigue life was calculated using a model based on the approach of Ioannides and Harris. The resulting residual stresses after the manufacturing process and their changes during operation in a bearing test rig are discussed and compared to those of standard bearings. The tests prove that pre-induced residual stresses increase is able to significantly delay rolling contact fatigue-related bearing failures.