Power transmission and pedal force sensing system for an electric bicycle

A pedal force sensing system for an electric bicycle, comprising:

• a crankshaft for pedals,
• a pedal force transmitting sleeve including an inner ring securely mounted around the crankshaft to rotate therewith, an outer ring surrounding the inner ring, and an elastic member mounted between the inner ring and the outer ring, wherein when the inner ring and the outer ring rotate relative to each other, the elastic member is deformed for generating a relative angular displacement between the inner ring and the outer ring,
• a pedal force sensing sleeve mounted around the crankshaft and adjacent to the pedal force transmitting sleeve, the pedal force sensing sleeve including a first side and a second side,
• at least one plane cam provided on the pedal force transmitting sleeve that faces the pedal force sensing sleeve such that when the pedal force sensing sleeve rotates relative to the pedal force transmitting sleeve, the pedal force sensing sleeve has a displacement relative to the crankshaft, and
• a sensor for sensing the displacement of the pedal force sensing sleeve relative to the crankshaft and outputting a voltage signal representing a magnitude of a pedal force.

A power transmission and pedal force sensing system for an electric motor having a rotor and a stator, comprising:

• a casing,
• a crankshaft adapted for attachment to pedals and extending through the casing,
• a hollow axle mounted around the crankshaft and including a first end in the casing and a second end extending beyond the casing and adapted to be securely connected to a chain wheel to rotate therewith,
• a motor hollow shaft mounted around the hollow axle, the crankshaft, the hollow axle and the motor hollow shaft being concentrically arranged in sequence, wherein the rotor is adapted to be mounted around the end of the motor hollow shaft, and the stator is adapted to be fixed to an inner periphery of the casing,
• a gear reduction train mounted to the end of the motor hollow shaft,
• a power combination mechanism for combining pedaling power from the crankshaft and power from the electric motor at the hollow axle to thereby drive the chain wheel,
• a pedal force transmitting sleeve including an inner ring securely mounted around the crankshaft to rotate therewith, an outer ring surrounding the inner ring, and an elastic member mounted between the inner ring and the outer ring, when the inner ring and the outer ring rotate relative to each other, wherein the elastic member is deformed for generating a relative angular displacement between the inner ring and the outer ring,
• a pedal force sensing sleeve mounted around the crankshaft and adjacent to the pedal force transmitting sleeve, the pedal force sensing sleeve including a first side and a second side,
• at least one plane cam provided on the pedal force transmitting sleeve that faces the pedal force sensing sleeve such that when the pedal force sensing sleeve rotates relative to the pedal force transmitting sleeve, the pedal force sensing sleeve has a displacement relative to the crankshaft, and
• a sensor for sensing the displacement of the pedal force sensing sleeve relative to the crankshaft and outputting a voltage signal representing a magnitude of a pedal force.