Speed change mechanism

A speed change mechanism for a motor, comprising:

• a. a first planetary gear set, comprising a first sun gear, a plurality of first planet pinions, a first carrier arm and a first ring gear;
• b. a second planetary gear set, comprising a second sun gear, a plurality of second planet pinions, a second carrier arm and a second ring gear;
• c. a third planetary gear set, comprising a third sun gear, a plurality of third planet pinions, a third carrier arm and a third ring gear;
• and
• d. a sleeve ring, the first and second planetary gear sets being located within the sleeve ring and drivingly coupled with the sleeve ring by means of corresponding first and second one-way clutches, the sleeve ring also having a power output;
• wherein a power input is connectable with one of the first sun gear and the first ring gear to drive the plurality of first planet pinions fixed by the first carrier arm to drive the other of the first sun gear and the first ring gear, the other of the first sun gear and first ring gear being coupled to drive the sleeve ring through the first one-way clutch, the other of the first sun gear and the first ring gear also being coupled with one of the second sun gear and the second ring gear to drive the second planet pinion fixed by the second carrier arm to drive the other of the second sun gear and the second ring gear, the other of the second sun gear and the second ring gear being coupled to drive the sleeve ring through the second one-way clutch, while the power output of the sleeve ring is connected with one of the third sun gear, the third planet pinion carrier and the third ring gear and a first other one of the third sun gear, the third planet pinion carrier and the third ring gear is drivingly coupled to a hub shell to output power to the hub shell.