Design of a modified hub geometry to reduce stress concentrations in interference-fit gear applications

Purpose Interference-fit joints are often used in power transmission systems because they can transmit high torque in a compact space. Even so, such joints associated with stress concentrations particularly near the hub–shaft interface, which can lead to fatigue failure especially in lightweight, thin-rim gear applications. In this work, a modified gear hub geometry using compound profile curves at the hub edges is proposed to reduce stress concentrations at the hub-shaft interface. The hub modifications suggested in this study keep the hub’s effective length and maintain structural integrity. Design/methodology/approach Three geometrical effective parameters – the hub bore radius aspect ratio (Qr), hub side angle (ϕ), and hub thickness factor (λ) – are analyzed using parametric nonlinear Finite Element Analyses (FEM). Findings The results show that the suggested hub-side modifications can enhance the von Mises stress, contact stress and tangential (hoop) stress by 38%, 55%, and 95%, respectively. These improvements were observed at a lower hub thickness factor and hub bore radius aspect ratio. In addition, it has been observed that the proposed design keeps the tensile stress at the shaft surface in an acceptable limit. This makes the joint more resistant to fatigue failures. Originality/value This work offers a gear hub design methodology to enhance the endurance and performance of the interference fit joints across various industrial systems without making manufacturing difficult.