Patent attributes
A drive system for a cycle has an input that receives drive from a pedal. An output rotates to drive a wheel via an electrical machine that provides motor drive. A drive train transmits drive to the output. The drive train includes first and second epicyclic gear sets EP-1, EP-2, which each include a sun gear, a planet carrier, a plurality of planet gears, and an annulus gear. Both annulus gears are connected to the output. Both sun gears are driven by the electrical machine. The first epicyclic gear set transmits drive from its sun gear to its annulus gear with its planet carrier in a fixed position. The second epicyclic gear set transmits drive from a pedal to its annulus gear via its planet carrier. Electrical assistance may be provided when the cyclist is pedalling and not pedalling.
