Pitch bearings are critical components in wind turbines, serving as the connection between blades and hub. Grease leakage and raceway edge damage are common failure modes of pitch bearings in engineering applications. Based on a practical engineering example, this paper presents a Finite Element Analysis (FEA) model of a pitch bearing system, in which contacts between steel ball rollers and raceways are simulated using nonlinear spring elements. This approach accounts for the flexibility of the entire pitch bearing system. Based on the FEA results, sealing capability of the sealing ring under system deformation is analyzed, revealing that the root cause of grease leakage in field applications is relative displacement between inner and outer rings, as well as breath effect. Additionally, contact loads and angles for each ball are derived from the FEA model and 3D solid local FEA models are constructed to investigate the impact of ellipse truncation on raceway load carrying capacity. The results highlight that ellipse truncation, caused by bearing deformation under flexible support structures, is a key factor in raceway edge damage.
Zhang et al. (Fri,) studied this question.