Derailleur

1. A derailleur, comprising:

a fixed component for being fixed to a bicycle frame;

a movable component for being fixed to a chain guide;

a linkage component comprising a first linkage with two ends which are opposite to each other and a second linkage with two ends which are opposite to each other, the two ends of the first linkage pivoting on the fixed component and the movable component, respectively, and the two ends of the second linkage pivoting on the fixed component and the movable component, respectively;

a deceleration component comprising:

a circular spline;

a flex spline disposed inside the circular spline, for rotating the first linkage and the second linkage relative to the fixed component; and

a wave generator disposed inside the flex spline; and

a drive component connected to the wave generator, for rotating the wave generator.

2. The derailleur according to claim 1 , further comprising a plurality of pivot pins, the flex spline further having a first torque output shaft, the first linkage and the second linkage pivoting on the fixed component and the movable component via the plurality of pivot pins, and the first torque output shaft being fixed to one of the plurality of pivot pins.

3. The derailleur according to claim 2 , wherein the circular spline of the deceleration component is fixed to the fixed component.

4. The derailleur according to claim 2 , wherein the circular spline of the deceleration component is fixed to the movable component.

5. The derailleur according to claim 2 , wherein the circular spline of the deceleration component is fixed to the first linkage.

6. The derailleur according to claim 2 , wherein the circular spline of the deceleration component is fixed to the second linkage.

7. The derailleur according to claim 1 , further comprising a plurality of pivot pins and a transmission component, the first linkage and the second linkage pivoting on the fixed component and the movable component via the plurality of pivot pins, the flex spline further having a first torque output shaft, the transmission component being connected to the first torque output shaft and one of the plurality of pivot pins for transmitting power to the first torque output shaft and the one of the plurality of pivot pins.

8. The derailleur according to claim 7 , wherein the circular spline of the deceleration component is fixed to the fixed component.

9. The derailleur according to claim 7 , wherein the circular spline of the deceleration component is fixed to the movable component.

10. The derailleur according to claim 7 , wherein the circular spline of the deceleration component is fixed to the first linkage.

11. The derailleur according to claim 7 , wherein the circular spline of the deceleration component is fixed to the second linkage.

12. The derailleur according to claim 7 , wherein the transmission component comprises a worm and a worm gear, the worm is fixed to the first torque output shaft coaxially, and the worm gear is fixed to the one of the plurality of pivot pins and meshed with the worm.

13. The derailleur according to claim 7 , wherein the transmission component comprises a first gear and a second gear, the first gear is fixed to the first torque output shaft coaxially, and the second gear is fixed to one of the plurality of pivot pins and meshed with the first gear.

14. The derailleur according to claim 1 , further comprising an elastic component with two ends which are opposite to each other, the two ends of the elastic component being connected to an end of the first linkage which is away from the fixed component and an end of the second linkage which is near the fixed component, respectively.

15. The derailleur according to claim 14 , wherein the elastic component is a tension spring.