Stability of Cage in Bearings of Reaction Wheels for Satellite Application: A Critical Review

The increased demand for better service in telecommunication, navigation, meteorology, broadcasting, data service, defence and security has made satellite technology one of the most focused areas in recent days. Large numbers of efficient, smaller and cost-effective satellites are being launched to Earth’s orbit for better precision and accuracy. So, in order to provide stability and controlled movement to these, miniature devices, such as reaction-type actuators, are used as wheels. These reaction wheels work on the principle of conservation of angular momentum. These wheels are capable of providing effective attitude control with minimal residual unbalance. The wheels are supported on an angular contact rolling element bearing. Though these bearings are designed and manufactured with strict aerospace procedures, the cage of these bearings often fail at high speeds and extreme atmospheric conditions. So, any defect in these wheels may cause failure to the entire mission. This study summarizes the research outcomes of causes of cage failure and their prevention. The research reveals that the failure of cages of high-speed bearings depends on the size of roller, roller contact force, misalignment, cage asymmetry, cage eccentricity, different loading conditions, radial clearance and cage pocket clearance. Roller bearing test rigs are being used to analyse effect of various parameters, like the bearing unbalance, shaft speed, number of rollers, etc., on cage dynamics as well as on cage slip. This investigation analyses the progress of relevant research, and identifies the shortcomings and future scope for further innovations.