Composite No-Back Brake for Flight Control Wear and Chatter
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Solution Overview
Problem
Conventional no-back brake devices in flight control actuation systems face issues with friction device wear, high-temperature resistance, and chatter, leading to reduced performance and increased maintenance costs.
Innovation Solution
The implementation of a bi-directional no-back brake system using a torque tube with a brake mechanism featuring alternating drag-brake and main-brake sections, incorporating composite material friction devices and metallic rotors, which form frictional couplings to prevent rotational motion and withstand high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional friction devices are used in no-back brake, then braking function is achieved, but friction device wear occurs before desired end of life
Solution Approach 1:
The friction device is made from a composite material comprising a metal matrix and a friction modifier distributed within the metal matrix. The metal matrix provides structural integrity and high-temperature resistance, while the friction modifier (such as graphite, PTFE, or MoS2) reduces wear and maintains stable friction characteristics. This composite structure resolves the contradiction by achieving reliable braking function while extending service life through reduced wear.
2Reliability
If conventional friction devices are used in no-back brake, then braking function is achieved, but high-temperature resistance is insufficient
Solution Approach 1:
The composite material structure with metal matrix provides high-temperature resistance while maintaining braking function. The metal matrix (such as aluminum, copper, or steel-based) retains structural stability at elevated temperatures, preventing deformation and maintaining braking effectiveness under thermal conditions.
3Reliability
If conventional friction devices are used in no-back brake, then braking function is achieved, but chatter occurs under certain operating conditions
Solution Approach 1:
The composite material with friction modifier provides stable friction characteristics that prevent chatter. The friction modifier ensures consistent friction force during braking operation, eliminating the oscillatory vibrations known as chatter that can occur with conventional friction materials. This resolves the contradiction by maintaining reliable braking while eliminating harmful chatter.
4Duration of action of moving object
If friction device wear is reduced through material improvement, then service life is extended, but device complexity increases
Solution Approach 1:
The composite material approach extends service life through wear reduction while maintaining relatively simple device structure. The composite friction device can be manufactured as a monolithic component or layered structure, avoiding the need for complex multi-component assemblies. This resolves the contradiction by achieving extended service life with minimal increase in structural complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enhances the service life, reduces wear, improves high-temperature resistance, and minimizes chatter, thereby increasing energy and loading capacities while maintaining effective braking performance.
Implementation Method 1
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
Data Source
AI summary
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.