Load distribution in the axial direction in a spline coupling

A finite element model has been made of a spline coupling between a shaft and a sleeve. The stress concentration factor is calculated and compared to analytical calculations. An analytical model for the load distribution in the axial direction and the torque transfer between shaft and sleeve is presented and compared to finite element results. Methods to uniform the load distribution and thereby decrease the stress concentration factor are tested with the analytical model. The induction hardened shafts with splines are fatigue tested and the lives are presented. The residual stress on the shaft surface is measured. The analytical model shows that the best way uniform the load is to vary the thickness of the spline tooth in the axial direction. Different shapes and sizes of the tooth thickness variation are also investigated. It is probably possible to extend the fatigue life at least two times for this spline, by uniforming the load distribution. (C) 2001 Elsevier Science Ltd. All rights reserved.