Patent ID: 7749121

Claim:
A transmission structure for an electrically operated bicycle, comprising an electric mechanism and a pedal mechanism; wherein the electric mechanism and the pedal mechanism are coaxially disposed on a pedal shaft of a bicycle, and one of the mechanisms is automatically selected to drive and rotate a driving chain wheel, wherein: a rotating shaft of the electric mechanism is a hollow tube that passes through two sides of the electric mechanism; the pedal shaft of the pedal mechanism penetrates and is disposed within the rotating shaft and is able to rotate therein; and the driving chain wheel is pivotal disposed on an outer side of the rotating shaft, one side of the driving chain wheel is coupled to the rotating shaft of the electric mechanism by means of a clutch, and the other side of the driving chain wheel is coupled to a pedal crank of the pedal mechanism by means of an unilateral bearing, and the clutch comprises a gear, a disk and two braking devices; the gear is fixed to the rotating shaft of the electric mechanism, and the disk assumes a dish shape and is pivotal disposed on the rotating shaft corresponding to position of the gear, and a braking surface is formed on a circumferential inner side of the disk; the two braking devices assume fan shapes, and are symmetrically pivotal disposed in an inner space of the disk by means of a pressure plate; a fan-shaped outer side edge of each of the braking devices is provided with outer teeth which mutually mesh with the gear, and braking plates respectively located on two ends of the fan shapes enable mutual contact and coupling with the braking surface of the disk.