Motorized mid-drive unit

A gearbox adapted for use on a mid-drive e-bike having footpedals and a driven wheel, the gearbox comprising:

• a bottom bracket shaft configured to rotate around a first rotational axis;
• an electric motor with an output rotational element configured to rotate about a second rotational axis;
• a plurality of gears comprising an output gear;
• a first one-way bearing configured to rotate around the first rotational axis and to enable power from the footpedals to be delivered to the driven wheel;
• and
• a second one-way bearing configured to rotate around a third rotational axis and to enable power from the electric motor to be delivered to the driven wheel;
• wherein the output gear is supported on the bottom bracket shaft by the second one-way bearing;
• and
• wherein the gearbox is configured to enable the e-bike to be propelled with:
• the footpedals alone, with the electric motor alone, and simultaneously with the footpedals and the electric motor.

A mid-drive e-bike gearbox, the gearbox comprising:

• a first shaft coupled to pedal cranks and to a pedal output gear such that the first shaft, pedal cranks, and pedal output gear are rotatable together;
• a second shaft coupled to a first offset gear, a second offset gear, and a motor transfer gear, such that the second shaft, first offset gear, second offset gear, and motor transfer gear are rotatable together;
• an electric motor having a motor output gear;
• an intermediate gear set interfaced with the motor output gear and with the motor transfer gear;
• an output gear interfaced with the second offset gear;
• a chain wheel coupled with the output gear such that the chain wheel and output gear are rotatable together;
• a first power path from the electric motor to the second offset gear;
• a second power path from the pedal cranks to the second offset gear;
• and
• a converged power path from the second offset gear to the output gear to the chain wheel.

A method of converting a non-motorized bike into a motorized bike, the method comprising:

• removing a pedal assembly from a bottom bracket shell of the bike, the bottom bracket shell having a first opening on a first lateral side, a second opening on a second lateral side opposite the first lateral side, and an axial axis that extends through the first and second openings;
• installing, along the axial axis, an engagement member of a motorized gearbox through the first opening and into the bottom bracket shell, the motorized gearbox further comprising a housing, an electric motor, an output gear, and a chain wheel;
• passing a distal end of the engagement member through the second opening such that a portion of the distal end protrudes out the bottom bracket shell;
• connecting a gearbox cover with the distal end of the engagement member;
• and
• attaching a pedal crank to the distal end of the engagement member.