CPC B62M 6/65 (2013.01) [B62M 11/16 (2013.01); B62M 11/18 (2013.01)] | 17 Claims |
1. A drive system for an electrically-assisted pedal cycle, the drive system comprising:
an input that receives drive from a pedal of the cycle and rotates about an axis;
an output that rotates about said axis and provides drive to a driven wheel of the cycle;
an electrical machine that provides motor drive to said output; and
a drive train that receives drive from the electrical machine and the pedal and transmits drive to said output;
wherein:
the drive train comprises a first epicyclic gear set and a second epicyclic gear set;
the first epicyclic gear set and second epicyclic gear set each comprise a sun gear, a planet carrier, a plurality of planet gears and an annulus gear, the planet gears being mounted on the planet carrier and meshing with both the sun gear and the annulus gear, and the annulus gear being connected to said output to rotate, in use, with said output;
both of the sun gears are connected to be driven by the electrical machine:
the first epicyclic gear set transmits drive from its respective sun gear to its respective annulus gear with its respective planet carrier in a fixed position; and
the second epicyclic gear set transmits drive from a pedal to its respective annulus gear via its respective planet carrier.
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