Patent ID: 6012538
Filing Date: 2000-01-11
Classification: B62M

Abstract:
A driving unit for an electric motor driven bicycle, comprising:a motor having an output shaft concentric with a crank shaft of a pedal;a planet roller reducer having a sun roller rotating integrally with said output shaft of the motor;a second-stage gear reducer for further reducing the rotation of a shaft of said planet roller reducer;a first one-way clutch interposed in a power transmission path of said second-stage gear reducer;a driving chain sprocket having a first gear which is concentric with said crank shaft and is engaged with an output shaft of said second-stage gear reducer;a second gear equal in pitch diameter to said first gear, supported through a bearing on said crank shaft of the pedal, and having a second one-way clutch for transmitting the rotation of said crank shaft to said driving chain sprocket;an angular displacement mechanism having an elastic member provided in said first gear and a protruding member protruding from said second gear to be engaged with said elastic member, said angular displacement mechanism converting the magnitude of a pedaling torque into angular displacement following deformation of said elastic member; andan angular displacement detecting mechanism for detecting the angular displacement produced in said angular displacement mechanism, wherein,an output torque of the motor is controlled in correspondence to the magnitude of said pedaling torque.