Hinge-line actuator for rotating an aircraft control surface

1. A hinge-line actuator comprising:

a drive shaft;

first and second ground gears spaced apart along the drive shaft, wherein the first and second ground gears include first and second contoured outer gear surfaces; and

an output gear disposed on the drive shaft and disposed between the first and second ground gears, wherein the output gear includes a third contoured outer gear surface;

an actuator housing that includes:

contoured first, second and third gear seats that, respectively, seat the first, second and third outer gear surfaces,

wherein:

the first and second gear seats are rotatably coupled to a first structure and the third gear seat is fixed to the first structure; and

the actuator housing includes:

first and second gear seat extensions that, respectively, extend from the first and second gear seats to a second structure; and

the actuator further comprises:

first and second wheel flanges that are, respectively, disposed against exterior facing surfaces of the first and second ground gears; and

first and second stub shafts that, respectively, extend outwardly from the first and second wheel flanges and surround the drive shaft, and

wherein the actuator housing has first and second centering brackets that are, respectively, disposed adjacent to the first and second gear seats,

the first centering bracket incudes a first axial arm that is disposed radially between, and axially aligned with, the first gear seat and the first sub shaft,

the second centering bracket incudes a second axial arm that is disposed radially between, and axially aligned with the second gear seat and the second sub shaft, and

wherein a first bearing that is disposed between the first axial arm of the first centering bracket and the first stub shaft, and a second bearing is disposed between the second axial arm of the second centering bracket and the second stub shaft.

2. The actuator of claim 1 , wherein:

the first, second and third outer gear surfaces are each shaped as polygons.

3. The actuator of claim 1 , further comprising:

a third bearing disposed between the first axial arm of the first centering bracket and the first gear seat; and

a fourth bearing disposed between the second axial arm of the second centering bracket and the second gear seat.

4. The actuator of claim 1 , wherein:

the first and second ground gears have a same gear configuration as each other; and

the first ground gear and the output gear have mutually differing gear configurations.

5. The actuator of claim 1 , wherein:

the drive shaft is configured to be driven by a motor that is spaced apart from the actuator housing.

6. The actuator of claim 1 , wherein:

the actuator housing is formed from a composite.

7. An aircraft comprising:

a movable structure;

a stationary structure;

a hinge-line actuator that rotatably couples the stationary structure to the movable structure, the hinge-line actuator including:

a drive shaft;

first and second ground gears spaced apart along the drive shaft, wherein the first and second ground gears include first and second contoured outer gear surfaces; and

an output gear disposed on the drive shaft and disposed between the first and second ground gears, wherein the output gear includes a third contoured outer gear surface;

an actuator housing in the movable structure that includes:

contoured first, second and third gear seats that, respectively, seat the first, second and third outer gear surfaces,

wherein:

the first and second gear seats are rotatably coupled to the movable structure and the third gear seat is fixed to the movable structure; and

the actuator housing includes:

first and second gear seat extensions that, respectively, extend from the first and second gear seats to the stationary structure; and

wherein:

the first and second ground gears, respectively, have first and second axial outer gear surfaces that face opposite directions along the drive shaft and

the actuator further includes:

first and second wheel flanges that are, respectively, disposed against the first and second axial outer gear surfaces; and

first and second stub shafts that, respectively, extend outwardly from the first and second wheel flanges and surround the drive shaft,

wherein the actuator housing has first and second centering brackets that are integrally connected to the movable structure and are, respectively, disposed adjacent to the first and second gear seats,

the first centering bracket incudes a first axial arm that is disposed radially between, and axially aligned with, the first gear seat and the first sub shaft,

the second centering bracket incudes a second axial arm that is disposed radially between, and axially aligned with the second gear seat and the second sub shaft, and

wherein a first bearing is disposed between the first arm of the first centering bracket and the first stub shaft, and a second bearing is disposed between the second arm of the second centering bracket and the second stub shaft.

8. The aircraft of claim 7 , wherein:

the first, second and third outer gear surfaces are each shaped as polygons.

9. The aircraft of claim 7 , further comprising:

a third bearing disposed between the first arm of the first centering bracket and the first gear seat; and

a fourth bearing disposed between the second arm of the second centering bracket and the second gear seat.

10. The aircraft of claim 7 , wherein:

the first and second ground gears have a same gear configuration as each other; and

the first ground gear and the output gear have mutually differing gear configurations.

11. The aircraft of claim 7 , wherein:

the drive shaft is driven by a motor that is spaced apart from the movable structure.

12. The aircraft of claim 11 , wherein

the motor is located in a fuselage or a wing.

13. The aircraft of claim 7 , wherein:

the actuator housing is formed from a composite.

14. The aircraft of claim 7 , wherein:

the stationary structure extends between forward and aft ends of the stationary structure;

the stationary structure aft end includes a stationary structure aft support that extends between inner and outer ends of the stationary structure, and the first and second gear seat extensions, respectively, extend from the first and second gear seats to the stationary structure aft support; and

the movable structure extends between the movable structure forward and aft ends, and the actuator housing is located at the movable structure forward end.

15. The aircraft of claim 14 , wherein:

the stationary structure is a wing;

the stationary structure forward end define a leading edge of a wing;

the stationary structure aft support is an aft spar;

the movable structure is a flap or aileron; and

the movable structure aft end defines a trailing edge of the wing.