Torque Transmission Characteristics of the Press Fit Joint Between the Aluminum Shaft and Steel Ring with Small Teeth

Abstract

Hybrid or aluminum tube structure requires reliable joining of the shaft to other components such as steel yoke and universal joint, which is often the most difficult task. Therefore, a reliable joining method between the aluminum tube and the steel yoke of a hybrid composite propeller shaft for automobile is required. In this work a press fitting method for joining of an aluminum tube to an aluminum yoke is devised by a steel ring with many small teeth to increase reliability as well as to reduce manufacturing cost of the hybrid propeller shaft rather than using other joining methods such as adhesively bonded or welded joints. The optimal shape and number of teeth of the steel ring were obtained experimentally for the maximum static torque capabilities and fatigue characteristics of the press fit joint, and was compared to the finite element analysis results. Finally, a design guideline for the press fit joint using a steel ring with many small teeth for joining the aluminum shaft to the steel ring was suggested. With the developed press fit joint, the static average shear strength of 70 MPa and fatigue strength of 21 MPa between the aluminum tube and the steel ring were realized, which were almost three times higher than that of the adhesively bonded joint.