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This paper presents an analysis of the contact and bending stresses of certain self-aligning automotive spur gear designs under various degrees of misalignment. The resulting deflection and stress fields are studied under quasi-static conditions and compared for different design variants. The proposed solution not only seems to eliminate the necessity to conduct gear tooth crowning, but also makes practical the increase of gear width and a corresponding reduction of the gear module, potentially further benefitting gear dynamics and efficiency.

High-ratio compound stepped planetary transmissions are typically characterised by poor overall efficiencies, even if the individual mesh efficiencies are high, because of the very high sliding velocities imposed by the kinematics of their topologies. Here, a parametric exploration of the design space is presented for a stepped transmission topology, which is assessed in terms of transmission ratio, efficiency, and power density. It is confirmed that high ratio per (compound) stage is accompanied by low mechanical efficiency and/or large volume for the most part of the parametric design space, as is also anticipated by prior research. At the same time, specific niche regions of particular importance are identified that combine high-ratio, high-efficiency, and good power density.