Bicycle controller and bicycle control system including bicycle controller

1. A bicycle controller comprising:

an electronic control unit that controls a transmission device, which is configured to change a ratio of a rotational speed of a wheel of a bicycle to a rotational speed of a crank of the bicycle, and a motor, which transmits torque to an upstream side of the transmission device in a transmission path of manual driving force that is input to the crank,

the electronic control unit being configured to switch between a first mode that drives the motor in accordance with the manual driving force and a second mode that allows the motor to be driven to assist walking of the bicycle, and

the electronic control unit is configured to control a rotational speed of the motor in accordance with the ratio in the second mode.

2. The bicycle controller according to claim 1 , wherein

the electronic control unit is configured to control the transmission device so that the ratio becomes less than or equal to a predetermined first ratio while in the second mode.

3. The bicycle controller according to claim 1 , wherein

the electronic control unit controls the rotational speed of the motor so that a difference between a vehicle speed before changing the ratio and a vehicle speed after changing the ratio becomes less than or equal to a predetermined value.

4. The bicycle controller according to claim 1 , wherein

the electronic control unit controls the rotational speed of the motor based on a map or table stored in a memory of the electronic control unit.

5. A bicycle control system comprising the bicycle controller according to claim 1 , and further comprising

the transmission device; and

the motor;

the transmission device including an internal transmission device.

6. A bicycle controller comprising:

an electronic control unit that controls a transmission device, which is configured to change a ratio of a rotational speed of a wheel of a bicycle to a rotational speed of a crank of the bicycle, and a motor, which transmits torque to an upstream side of the transmission device in a transmission path of manual driving force that is input to the crank,

the electronic control unit being configured to switch between a first mode that drives the motor in accordance with the manual driving force and a second mode that allows the motor to be driven to assist movement of the bicycle while a rider walks and pushes the bicycle, and

the electronic control unit is configured to control the transmission device to decrease the ratio upon detection of an output torque of the motor becoming greater than or equal to a predetermined torque while in the second mode.

7. The bicycle controller according to claim 6 , wherein

the electronic control unit is configured to control the rotational speed of the motor upon detection of the transmission device changing the ratio so that a difference between a vehicle speed of the bicycle before the ratio is changed and the vehicle speed of the bicycle after the ratio is changed is less than or equal to a predetermined value.

8. The bicycle controller according to claim 6 , wherein

the electronic control unit controls the transmission device in predetermined cycles as long as the bicycle controller is supplied with power.

9. The bicycle controller according to claim 6 , wherein

the electronic control unit detects the output torque of the motor from a command that operates the motor.

10. The bicycle controller according to claim 6 , wherein

the electronic control unit detects the output torque of the motor from the current flowing to the motor.

11. The bicycle controller according to claim 6 , wherein

the electronic control unit controls the rotational speed of the motor based on a map or table stored in a memory of the electronic control unit.

12. The bicycle control system according to claim 11 , further comprising

a clutch that interrupts transmission of rotation of the motor to the crank in a situation in which the bicycle moves forward.