Load distribution and pitch errors 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. The pitch error caused by the irregular spacing between the spline teeth has been measured. The irregular spacing is caused by an imprecise milling operation and the volumetric distortion after induction hardening. The measurement of pitch error has been made of splines manufactured using two different milling methods. A simplified model has been created to calculate the approximate load on each tooth and the relative life. Induction hardened shafts with splines manufactured with one type of milling method have been fatigue tested. The calculations have showed that the life of a spline with pitch error is only 1/3–1/2 of the life of a spline with ideal pitching.