Fatigue life of double row slewing ball bearing with irregular geometry

AbstractStandard procedure for bearing life calculation, as described in standard ISO281:2008, was developed for standard, rather small axial or thrust rolling bearings. Since the geometry and manufacturing procedures of large rolling slewing bearings are considerably different from those of standard rolling bearings, different calculation procedures have to be used. The paper describes a computational procedure, where the geometry of the bearing is described with vectors, which enables modelling of irregular shapes of the bearing rings. These can be a result of the manufacturing procedure or of the deformations caused by the operating conditions. The calculation procedure consists of calculation of the maximum contact force on the rolling element, which is done by the in-house developed program, and detailed finite element analysis of the contact between the ball and the raceway. The finite element analysis also takes into account depth-dependent material parameters of a raceway. Different calculation theories are then used for the calculation of fatigue life, and a comparison of the results is made at the end