Abstract
Geared transmissions are as ubiquitous, as they are essential to nearly every mechanical powertrain. There is a large and growing body of research on gear geometry, with a focus on manufacturing, errors and accuracy, on gear strength, lubrication, efficiency, noise and vibration, for practically all known embodiments of parallel axes, intersecting axes and non-intersecting axes- spatial configurations. Configurations of planetary transmissions are also studied extensively - not least in terms of topology due to their importance to automatic transmissions, and to a lesser but growing extent also cycloidal transmissions, strain-wave transmissions and other exotic but singular architectural configurations are subject to continued research and development. This research and development landscape is far from exhaustive, however; we argue that an extensive part of the - at this time conceivable - design space is largely unexplored: not only in terms of gear contact geometry and associated kinematic and dynamic response and function, but mostly in terms of topology and architecture, either alone or in combination with geometry. We reason, map and anticipate significant innovations and lay a roadmap for future research and technology development. We also make the essential links to use cases from the fields of aerospace engineering, automotive engineering, robotics, and energy.