Mid-motor drive system for an electric bicycle

1. A mid-motor drive system for an electric bicycle, comprising a left shell ( 1 ), a right shell ( 2 ), a motor assembly ( 3 ), a gear reduction apparatus ( 4 ), a torque sensor ( 5 ), a central shaft ( 7 ), a controller ( 8 ), and a crankset ( 9 ), and further comprising a planetary gear increase apparatus ( 6 ), wherein the gear reduction apparatus ( 4 ) is connected to the motor assembly ( 3 ), the planetary gear increase apparatus ( 6 ), and the crankset ( 9 ), the planetary gear increase apparatus ( 6 ) is connected to the torque sensor ( 5 ) and the central shaft ( 7 ), the torque sensor ( 5 ) is connected to the controller ( 8 ), and the controller ( 8 ) is connected to the motor assembly ( 3 ), the torque sensor ( 5 ) comprises a deformation support, a signal transmission module ( 502 ), and a magnetic component, the deformation support is deformed under a force to actuate the magnetic component to move, and the signal transmission module ( 502 ) senses the movement of the magnetic component, converts a change of magnetic flux into an electrical signal, and transfers the electrical signal to the controller ( 8 ),

the motor assembly ( 3 ) comprises a motor stator ( 301 ), a motor internal rotor ( 302 ), and a gear shaft ( 303 );

the gear reduction apparatus ( 4 ) comprises a first stage reduction gear wheel ( 401 ), a second stage reduction pinion ( 402 ), a unidirectional bearing ( 403 ), and a second stage reduction gear wheel ( 404 );

the planetary gear increase apparatus ( 6 ) comprises a gear ring ( 601 ), a planetary shaft pin ( 602 ), a ratchet fixing seat ( 603 ), an arm ( 604 ), a solar wheel ( 605 ), a ratchet-type unidirectional clutch ( 606 ), and a planetary gear ( 607 );

the torque sensor ( 5 ) is installed on the left shell ( 1 ), and the controller ( 8 ) is installed on the right shell ( 2 );

wherein the deformation support of the torque sensor ( 5 ) is an aluminum alloy deformation body ( 501 ), and the magnetic component comprises a plastic support ( 503 ), a steel ball ( 505 ), a spring ( 507 ), a circular magnet ( 504 ), and a plastic slider ( 506 ).

2. The mid-motor drive system for the electric bicycle according to claim 1 , wherein the first stage reduction gear wheel ( 401 ) of the gear reduction apparatus ( 4 ) is engaged with the gear shaft ( 303 ) of the motor assembly ( 3 ).

3. The mid-motor drive system for the electric bicycle according to claim 1 , wherein the crankset ( 9 ) is installed on the second stage reduction gear wheel ( 404 ) of the gear reduction apparatus ( 4 ).

4. The mid-motor drive system for the electric bicycle according to claim 1 , wherein four planetary gears ( 607 ) of the planetary gear increase apparatus ( 6 ) are fixed on the arm ( 604 ) and rotate with the central shaft ( 7 ) being the center of rotation.

5. The mid-motor drive system for the electric bicycle according to claim 1 , wherein the arm ( 604 ) of the planetary gear increase apparatus ( 6 ) is installed on the central shaft ( 7 ) through a bearing, and the ratchet-type unidirectional clutch ( 606 ) is provided between the central shaft ( 7 ) and the arm ( 604 ).

6. The mid-motor drive system for the electric bicycle according to claim 1 , wherein the gear ring ( 601 ) of the planetary gear increase apparatus ( 6 ) is fixed on the second stage reduction gear wheel ( 404 ) of the gear reduction apparatus ( 4 ).

7. The mid-motor drive system for the electric bicycle according to claim 1 , wherein the signal transmission module ( 502 ) of the torque sensor ( 5 ) comprises a linear Hall element and a signal lead wire.

8. The mid-motor drive system for the electric bicycle according to claim 1 , wherein the solar wheel ( 605 ) of the planetary gear increase apparatus ( 6 ) is connected to the deformation support.