Self-locking Actuator with Swivel Assembly for Flight Control
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Solution Overview
Problem
Modern aircraft flight control actuators face challenges in resisting external forces and vibrations, particularly due to the susceptibility of traditional 'no-back' mechanisms to creep under certain load and vibration conditions, which can lead to unintended position changes of flight control surfaces.
Innovation Solution
A self-locking actuator design incorporating a motor, screw, drive gear, pawl support, and swivel assembly that engages a cage with circumferentially spaced slots, allowing the actuator to positively lock in both rotational directions, preventing unwanted movement of flight control surfaces under external loads through a lost motion configuration and pivoting mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a positive locking mechanism with multiple components is implemented, then the actuator can prevent creep and provide bidirectional locking, but the device complexity increases
Solution Approach 1:
The patent merges multiple locking functions into a single integrated mechanism where pawls, teeth, and spring elements work together as a unified system. This merging reduces the number of separate components compared to using multiple independent locking mechanisms, thereby reducing overall complexity while maintaining creep resistance and bidirectional locking capabilities.
Solution Approach 2:
The pawl assembly serves multiple functions simultaneously: it provides positive locking, prevents creep, enables bidirectional rotation control, and absorbs vibration. This multi-functionality reduces the need for additional specialized components, simplifying the overall device architecture while achieving high reliability.
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
The self-locking actuator effectively resists external loads and vibrations, maintaining precise control of flight control surfaces by preventing rotation in both directions, thus ensuring stable aircraft trajectory and reducing the risk of over-movement or damage from external forces.
Implementation Method 1
Pivoting of the swivel assembly about a pivot axis engages the swivel assembly with the cage to positively lock with the cage and to prevent rotation of the screw
Implementation Method 2
a drive gear that is rotatably driven by the motor to rotationally couple with the screw
Implementation Method 3
the drive gear is disposed in a lost motion configuration with the screw such that the drive gear is driven to pivot the swivel assembly between engagement and disengagement with one of the plurality of cage slots prior to the drive gear being driven to engage the screw
Data Source
AI summary
A self-locking actuator for moving a flight control surface of an aircraft and for self-locking in response to an external load applied to the actuator. The actuator includes a motor, a screw, and a drive gear that is rotatably driven by the motor to rotationally couple with the screw. A pawl support is coupled to and rotatable with the screw, and a swivel assembly is coupled to the pawl support for rotational movement with the screw and pivoting movement relative to the screw. The swivel assembly engages a cage that is fixed relative to the rotating screw, drive gear, and swivel assembly. Pivoting of the swivel assembly about a pivot axis engages the swivel assembly with the cage to positively lock with the cage and to prevent rotation of the screw in each of first and second opposite rotational directions of the screw about a rotational axis of the screw.