The effect of cage pocket shape on dynamic characteristics of angular contact ball bearing under starved lubrication

The dynamic performance of angular contact ball bearings (ACBBs) in spacecraft inertial actuators is significantly influenced by structural parameters and lubrication conditions, which affect operational accuracy and reliability. In this study, a full-degree-of-freedom nonlinear dynamic model of ACBBs is developed, incorporating time-varying lubrication, multi-component interactions, and five cage pocket shapes (circular, square, rhombic, obround, and rectangular). The model is validated against experimental results. Subsequently, the effects of oil supply, cage pocket shape, and pocket clearance on dynamic characteristics, including friction torque and cage instability, are systematically investigated under starved lubrication. Results show that friction torque initially decreases and then increases with increasing oil supply. For constant circumferential clearance, limiting the axial dimension by optimizing the pocket shape (obround or rectangular pockets) can reduce friction torque, suppress torque fluctuations, and improve cage stability. Increasing circumferential clearance decreases the mean torque but exacerbates fluctuations; obround and rectangular pockets achieve a balance between low friction and stability, whereas rhombic pockets exhibit the highest stability. These findings provide theoretical guidance for optimizing ACBB performance in spacecraft inertial actuators.