Reliability-based residual life prediction of large-size low-speed slewing bearings

Critical failure of a slewing bearing used in large machines would bring disastrous loss to an enterprise. Accurate residual life prediction of a slewing bearing can reduce unexpected accidents and unnecessary maintenances. In this paper, a residual life reliability prediction approach for slewing bearings was firstly presented based on the Weibull distribution. Afterwards, a novel approach for parameter estimation was proposed based on a small-sample test, which built the relationship between the characteristic life of a slewing bearing and the maximal load over the raceway. To verify the proposed approach, a full-load accelerated life test was implemented on a QNA-730-22 slewing bearing. It was observed that the damage of the outer (fixed) ring caused the failure of the slewing bearing, while the inner (rotatable) ring was still in good condition. After which, the residual life prediction model was then established by the proposed approach. Compared to ISO 281 and NREL design guide 03, the proposed approach is closer to engineering practice, and thus has the potential for slewing bearing prognostics.