CAGEDYN: A Contribution to Roller Bearing Dynamic Calculations. Part III: Experimental Validation

Abstract

Models used in CAGEDYN and described in Parts I and II have been validated by comparing calculated and measured values of the impact force of a ball falling on a beam, the hydrodynamic rolling force (due to the Poiseuille flow or pressure gradient in the inlet of an elastohydrodynamic lubrication [EHL] contact and responsible for the so-called hydrodynamic race torque, even when operating under pure rolling conditions), the sliding traction force in an EHL contact, bearing cage impact forces, and bearing cage slip. A description of the bearing test rig used for measuring cage impact force and cage slip is presented. The correlation obtained is satisfactory, especially when looking at the trends. The impact force increases when increasing the roller–cage pocket clearance, increasing the bearing end play (or bearing axial clearance, which causes a reduction of the load zone), and increasing the shaft speed. At very light radial load, the impact force increases with increasing radial load to a maximum value and then decreases as the radial load continues to increase. Cage slip increases as the radial load decreases and the shaft speed increases. Past cage failures and cage solutions to recent cage problems in real field applications have been explained using CAGEDYN and comparing the maximum calculated cage stress to the cage material fatigue limit.