No-back brake for a flight control actuation system and method
A no-back brake includes a torque tube and a brake. The brake is configured to be axially displaced in response to a force to prevent the torque tube from rotating. The brake includes a rotor that is concentric with the torque tube and that is fixed to the torque tube so that the rotor rotates with the torque tube. The brake includes a stator that is concentrically mounted on the torque tube so that the torque tube is rotatable relative to the stator. The brake includes a friction device located between the rotor and the stator. The friction device is configured to form a frictional coupling between the rotor and the stator that opposes relative rotational motion between the rotor and the stator when the brake is axially displaced. The frictional device includes a composite material.
1 . A no-back brake comprising:
a torque tube; and
a brake configured to be displaced in response to a force to prevent the torque tube from rotating, wherein the brake comprises:
a rotor concentric with the torque tube and fixed to the torque tube so that the rotor rotates with the torque tube;
a stator concentrically mounted on the torque tube so that the torque tube is rotatable relative to the stator; and
a friction device located between the rotor and the stator,
wherein:
the friction device is configured to form a frictional coupling between the rotor and the stator that opposes relative rotational motion between the rotor and the stator when the brake is displaced;
the frictional device comprises a composite material;
the friction device comprises a friction surface and at least one channel formed in the friction surface; and
the at least one channel is configured to move oil between the stator and the rotor when the rotor rotates.
2 . The no-back brake of claim 1 , wherein the rotor comprises a metallic material.
3 . The no-back brake of claim 2 , wherein the metallic material is a metallic alloy.
4 . The no-back brake of claim 2 , wherein the metallic material is a silicon-vanadium steel alloy.
5 . The no-back brake of claim 2 , wherein the metallic material of the rotor has a Rockwell C Hardness value of at least 55.
6 . The no-back brake of claim 1 , further comprising:
a ball ramp plate coupled to the torque tube; and
a spring, coupled to the torque tube and to the brake,
wherein:
the ball ramp plate is configured to receive the force and to be displaced in response to the force;
the brake is coupled to the ball ramp plate and is configured to be displaced by the ball ramp plate corresponding to a distance that the ball ramp plate is displaced; and
the spring is configured to compress in response to the brake being displaced to apply a selective compressive force at the brake corresponding to a distance the brake is displaced.
7 . The no-back brake of claim 6 , wherein the ball ramp plate is axially displaced by the force and is configured to move the brake and to compress the spring.
8 . The no-back brake of claim 1 , wherein the friction device has a coefficient of friction of between approximately 0.08 and 0.12.
9 . The no-back brake of claim 8 , wherein the composite material of the friction device is configured to resist temperatures up to approximately 275° F. without experiencing a decrease in the coefficient of friction.
10 . The no-back brake of claim 1 , further comprising a housing that contains at least a portion of the torque tube and the brake,
wherein the housing forms an internal cavity that is at least partially filled with the oil.
11 . The no-back brake of claim 10 , wherein:
the stator comprises a stator spline that is coupled to the housing to prevent the stator from rotating when the friction coupling is formed between the rotor and the stator; and
the stator spline has a spline profile configured to enable the oil to move over the stator, between the stator and the housing.
12 . The no-back brake of claim 1 , wherein the composite material is a fiber-reinforced composite.
13 . The no-back brake of claim 1 , wherein the composite material is a carbon-fiber-reinforced composite.
14 . The no-back brake of claim 1 , wherein the composite material is a non-woven carbon-fiber composite.
15 . The no-back brake of claim 1 , wherein the friction device has a surface roughness of less than approximately 0.06 μm Ra.
16 . The no-back brake of claim 1 , wherein the friction device is coupled to the stator.
17 . The no-back brake of claim 1 , wherein at least the one channel extends radially across the friction surface from proximate the torque tube.
18 . The no-back brake of claim 1 , wherein:
the stator comprises a stator spline configured for coupling to a housing to prevent the stator from rotating when the friction coupling is formed between the rotor and the stator; and
the stator spline has a spline profile configured to enable the oil to move over the stator.
19 . A no-back brake comprising:
a torque tube; and
a brake configured to be displaced in response to a force to prevent the torque tube from rotating, wherein the brake comprises:
a drag brake section comprising a plurality of drag-brake stators and a plurality of drag-brake rotors alternatingly arranged along a first portion of the torque tube;
a main brake section comprising a plurality of main-brake stators and a plurality of main-brake rotors alternatingly arranged along a second portion of the torque tube; and
a plurality of friction devices, wherein one of the plurality of friction devices is located between each one of the plurality of drag-brake stators and the plurality of drag-brake rotors and one of the plurality of friction devices is located between each one of the plurality of main-brake stators and the plurality of main-brake rotors,
wherein:
each one of the plurality of drag-brake rotors and each one of the plurality of main-brake rotors is concentric with the torque tube and is fixed to the torque tube so that each one of the plurality of drag-brake rotors and each one of the plurality of main-brake rotors rotates with the torque tube;
each one of the plurality of drag-brake stators and each one of the plurality of main-brake stators is concentrically mounted on the torque tube so that the torque tube is rotatable relative to each one of the plurality of drag-brake stators and each one of the plurality of main-brake stators;
each one of the friction devices is configured to form a frictional coupling between a corresponding pair of the plurality of drag-brake stators and the plurality of drag-brake rotors and between a corresponding pair of the plurality of main-brake stators and the plurality of main-brake rotors that opposes relative rotational motion between the plurality of drag-brake stators and the plurality of drag-brake rotors and relative rotational motion between the plurality of main-brake stators and the plurality of main-brake rotors when the brake is displaced;
each one of the friction devices comprises a composite material;
at least one of the friction devices comprises a friction surface and at least one channel formed in the friction surface; and
the at least one channel is configured to move oil between the corresponding pair of the plurality of drag-brake stators and the plurality of drag-brake rotors or between a corresponding pair of the plurality of main-brake stators and the plurality of main-brake rotors in response to rotation.
20 . A flight control actuation system comprising:
a dynamic aerodynamic surface that is moveable relative to a static aerodynamic surface;
an actuator assembly to drive movement of dynamic aerodynamic surface in response to a power input; and
a no-back brake disposed within the actuator assembly, wherein the no-back brake comprises:
a torque tube configured to rotate in response to the power input; and
a brake configured to be displaced in response to a force to prevent the torque tube from rotating, wherein the brake comprises:
a rotor concentric with the torque tube and fixed to the torque tube so that the rotor rotates with the torque tube;
a stator concentrically mounted on the torque tube so that the torque tube is rotatable relative to the stator; and
a friction device located between the rotor and the stator,
wherein:
the friction device is configured to form a frictional coupling between the rotor and the stator that opposes relative rotational motion between the rotor and the stator when the brake is displaced;
the frictional device comprises a composite material;
the friction device comprises a friction surface and at least one channel formed in the friction surface; and
the at least one channel is configured to move oil between the stator and the rotor when the rotor rotates.
21 . A method comprising steps of:
receiving a force at a no-back brake;
displacing a brake of the no-back brake in response to the force; and
forming a frictional coupling between a rotor of the brake and a stator of the brake that opposes relative rotational motion between the rotor and the stator using a friction device of the brake when the brake is displaced; and
moving oil between the stator and the rotor when the rotor rotates,
wherein:
the rotor is concentric with a torque tube of the no-back brake and is fixed to the torque tube so that the rotor rotates with the torque tube;
the stator is concentrically mounted on the torque tube so that the torque tube is rotatable relative to the stator; and
the friction device is located between the rotor and the stator,
the frictional device comprises a composite material, a friction surface, and at least one channel formed in the friction surface; and
the at least one channel is configured to move oil between the stator and the rotor.