Dynamic modeling and analysis of local defect system of rolling bearing outer ring

Rolling bearings are of fundamental importance in rotating machinery. Outer - ring spalling, in particular, stands as a commonly encountered and quintessential defect. The dynamic model of rolling bearings enables an in-depth analysis of the dynamic response characteristics associated with local bearing defects. In this paper, by meticulously examining the change in the spherical center position as rolling elements pass through the fault region of the bearing outer ring, random sequences are utilized to simulate the appearance of the fault bottom. Simultaneously, factors such as centrifugal force and gyroscopic torque are integrated into the model formulation. This integration culminates in the establishment of an advanced dynamic model tailored to local faults on the outer ring of rolling bearings. Utilizing the ER − 16K bearing as the experimental specimen, comprehensive numerical solution computations and experimental validations of the proposed model were meticulously executed. Comparisons were carried out between the time-domain and frequency-domain responses obtained from experiments and simulations under diverse rotational speeds, and the effect of varying local fault depths on vibration characteristics was explored. The findings reveal that, in contrast to traditional models, the newly developed model in this study exhibits high precision, minimal error, and can proficiently simulate vibration characteristics, with a maximum error of merely 3.91%. Moreover, this study reveals that the fault-characteristic frequency increases proportionally with rotational speed, and the vibration - acceleration amplitude notably enlarges as fault depth deepens. These findings provide a theoretical basis for rolling - bearing fault diagnosis.