Force Analysis Due to Local Defect in Rolling Bearings for Fault Diagnosis

Local defects in races of rolling bearings generate periodic forces whose strength is largely governed by the defect size. An insight into force generation mechanism and its relationship with defect size is essential to identify the bearing health. This work presents an engineering mechanics based approach to model the forces at different events as a rolling element negotiates a fault on the race. The forcing function is modeled at entry, as a function of load, speed and curvature of defect and due to impact as a function of defect size, defect location, speed and load on the bearing. The impulse of impact force and the duration between entry and impact forces, termed as Time to Impact (TTI), are indicators of the defect size. The proposed model may provide a potential basis for implementing direct monitoring with embedded force sensor module.