Bicycle internal transmission hub

1. A bicycle internal transmission hub comprising:

a hub housing including a hub shell having a cylindrical shape and configured to be coupled to a bicycle wheel rim, the hub shell defining an accommodation cavity inside the cylindrical shape;

a hub axle;

a shifting unit located in the accommodation cavity and configured to select one speed stage from a plurality of speed stages;

a drive shaft arranged to drive the shifting unit via a link configured to convert rotation of the drive shaft into translational motion of a contact member;

an electric actuator located in the accommodation cavity to drive the shifting unit, the electric actuator having an output shaft arranged parallel to the hub axle; and

a gear mechanism including at least one gear, the gear mechanism being disposed between the output shaft and the drive shaft such that rotation of the output shaft is transmitted to the drive shaft through the gear mechanism.

2. The bicycle internal transmission hub according to claim 1 , further comprising

a power generation mechanism that generates power used to drive the electric actuator.

3. The bicycle internal transmission hub according to claim 2 , wherein

the power generation mechanism is located in the accommodation cavity.

4. The bicycle internal transmission hub according to claim 2 , further comprising

a power storage mechanism that stores power supplied from the power generation mechanism.

5. The bicycle internal transmission hub according to claim 4 , wherein

the power storage mechanism is located in the accommodation cavity.

6. The bicycle internal transmission hub according to claim 1 , further comprising

an electronic control unit that controls the electric actuator.

7. The bicycle internal transmission hub according to claim 6 , wherein

the electronic control unit is located in the accommodation cavity.

8. The bicycle internal transmission hub according to claim 3 , wherein

the hub shell includes a first end and a second end with respect to a center axis of the hub shell,

the electric actuator is at least partially located toward the first end of the hub shell with respect to the shifting unit, and

the power generation mechanism is at least partially located toward the second end of the hub shell with respect to the shifting unit.

9. The bicycle internal transmission hub according to claim 8 , further comprising

a power storage mechanism located in the accommodation cavity and that stores power supplied from the power generation mechanism, the power storage mechanism being at least partially located toward the first end of the hub shell with respect to the shifting unit.

10. The bicycle internal transmission hub according to claim 9 , further comprising

an electronic control unit that is located in the accommodation cavity and controls the electric actuator, the electronic control unit being located toward the first end of the hub shell with respect to the shifting unit.

11. The bicycle internal transmission hub according to claim 10 , further comprising

a first support member located toward the first end of the hub shell with respect to the shifting unit to support the shifting unit, the electric actuator being located on the first support member.

12. A bicycle internal transmission hub comprising:

a hub housing including a hub shell having a cylindrical shape and configured to be coupled to a bicycle wheel rim, the hub shell defining an accommodation cavity inside the cylindrical shape, the hub shell including a first end and a second end with respect to a center axis of the hub shell;

a shifting unit located in the accommodation cavity and configured to select one speed stage from a plurality of speed stages;

an electric actuator located in the accommodation cavity to drive the shifting unit, the electric actuator being at least partially located toward the first end of the hub shell with respect to the shifting unit;

a power generation mechanism that generates power used to drive the electric actuator, the power generation mechanism being located in the accommodation cavity at least partially toward the second end of the hub shell with respect to the shifting unit;

a power storage mechanism located in the accommodation cavity and that stores power supplied from the power generation mechanism, the power storage mechanism being at least partially located toward the first end of the hub shell with respect to the shifting unit;

an electronic control unit that is located in the accommodation cavity and controls the electric actuator, the electronic control unit being located toward the first end of the hub shell with respect to the shifting unit;

a first support member located toward the first end of the hub shell with respect to the shifting unit to support the shifting unit, the electric actuator being located on the first support member; and

a second support member located toward the second end of the hub shell with respect to the shifting unit to support the shifting unit, the power generation mechanism being located closer to the second end of the hub shell than the second support member.

13. A bicycle internal transmission hub comprising:

a hub housing including a hub shell having a cylindrical shape and configured to be coupled to a bicycle wheel rim, the hub shell defining an accommodation cavity inside the cylindrical shape, the hub shell including a first end and a second end with respect to a center axis of the hub shell;

a shifting unit located in the accommodation cavity and configured to select one speed stage from a plurality of speed stages;

an electric actuator located in the accommodation cavity to drive the shifting unit, the electric actuator being at least partially located toward the first end of the hub shell with respect to the shifting unit;

a power generation mechanism that generates power used to drive the electric actuator, the power generation mechanism being located in the accommodation cavity at least partially toward the second end of the hub shell with respect to the shifting unit;

a power storage mechanism located in the accommodation cavity and that stores power supplied from the power generation mechanism, the power storage mechanism being at least partially located toward the first end of the hub shell with respect to the shifting unit;

an electronic control unit that is located in the accommodation cavity and controls the electric actuator, the electronic control unit being located toward the first end of the hub shell with respect to the shifting unit; and

a first support member located toward the first end of the hub shell with respect to the shifting unit to support the shifting unit, the electric actuator being located on the first support member,

the power storage mechanism being located on the first support member.

14. The bicycle internal transmission hub according to claim 11 , wherein

the electronic control unit is located on the first support member.

15. The bicycle internal transmission hub according to claim 6 , further comprising

a wireless communication unit electrically connected to the electronic control unit to communicate with an external device.

16. The bicycle internal transmission hub according to claim 15 , wherein

the wireless communication unit is at least partially located in the accommodation cavity.

17. The bicycle internal transmission hub according to claim 1 , further comprising

a notification unit that issues a notification of a state of the bicycle internal transmission hub.

18. The bicycle internal transmission hub according to claim 1 , wherein

the hub shell includes:

a shell body coupled to a rim of a wheel by an intermediate member that is coupled to the rim; and

a cover member rotatably arranged on the shell body.

19. The bicycle internal transmission hub according to claim 1 , wherein

the electric actuator is configured to adjust a rotational angle of the drive shaft corresponding to the one speed stage so that the shifting unit selects the one speed stage.