Dynamic modeling of cylindrical roller bearings considering raceway crack defects

When non-through crack defects occur in cylindrical roller bearings (CRBs), they can affect the vibration level and service life of the bearings and even the rotor system. When the roller rolls over the raceway with non-through crack defects, the time-varying stiffness (TVS) between the roller and the raceway will change. To explore this problem, this paper proposes a stiffness-equivalent model and incorporates it into the dynamic model of the CRB. Then a test bench was built to compare and analyze the experimental results with those in the theoretical model. The influence of the size and inclination angle of non-through crack defects on the vibration characteristics and TVS of the CRBs was investigated. The results indicate that the excitation amplitude of the TVS increases with the depth and length of the crack defect, whereas the inclination angle of the crack defect reduces the TVS excitation amplitude. Then non-through crack defects contribute to the vibration of the CRBs with the changes in TVS excitation amplitude. This research can provide a theoretical basis for the fault diagnosis of CRBs.