Driving unit for an electric motor driven bicycle
First Claim
Patent Images
1. 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; and
an 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.
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Abstract
In a driving unit for an electric motor driven bicycle, a motor (31) has an output shaft coaxial with a crank shaft (39) of a pedal. A planet roller reducer (40) has a sun roller shaft coincident with the output shaft. Through the planet roller reducer (40) and a two-stage reducing gear mechanism (50) for further reducing the output of the planet roller reducer (40), a torque of the motor (31) is transmitted to a driving chain sprocket (4). Provided that the torque of the motor (31) exceeds a predetermined pedaling torque level, the torque is transmitted to the driving chain sprocket (4).
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Citations
20 Claims
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1. A driving unit for an electric motor driven bicycle, comprising:
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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; and an 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. - View Dependent Claims (2, 3, 4, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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5. A driving unit for an electric motor driven bicycle, comprising:
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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 at a final stage which is concentric with said crank shaft and 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; and a torque detecting mechanism having third and fourth gears arranged on a common axis to be engaged with said first and said second gears, respectively, said torque detecting mechanism being responsive to a pedaling torque transmitted through said two pairs of gears for producing axial displacement proportional to a transmission torque between said third and said fourth gears, wherein an output torque of the motor is controlled in correspondence to the magnitude of said pedaling torque. - View Dependent Claims (6, 7)
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18. A motor power assistance system for a bicycle having a crank shaft, pedals for rotating the crank shaft, and a sprocket for transmitting rotation of the crankshaft to a driving wheel, the system comprising:
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a first gear connected to the crank shaft through a first one-way clutch; a second gear connected to said sprocket; a motor provided coaxially with the crank shaft and transmitting output torque to said second gear through a second one-way clutch; a torque transmitting unit which transmits torque at least from said second gear to said first gear while permitting a relative displacement therebetween; an angular displacement detecting unit which detects the angular displacement between said first and second gears; and a control unit which controls an out put of said motor based on said detected angular displacement. - View Dependent Claims (19, 20)
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Specification