Deflection Characteristics of a Statically Loaded Multiple-Bearing Differential Pinion Shaft

Theoretical and experimental determinations of load and deflection at the spigot bearing position were performed on a straddle-mounted (3-bearing) differential pinion shaft in a complete truck differential and carrier assembly. Two theoretical calculation methods are used; namely, a widely used approximate method that considers the shaft to be supported by two bearings and a digital computer method that treats the shaft as a statically indeterminate structure. Loads on the spigot bearing were measured using the Contact Pattern Analysis technique, while deflections were measured with strain gage displacement transducers, all under a statically applied input torque. Comparison of theoretical and experimental results show that the actual loads are more consistent with a 3-bearing statically indeterminate system calculation than with a simplified 2-bearing theoretical approach. Further refinement of the elastic model of the bearings is suggested to provide even closer agreement.