Actuator Torque-Reaction Rod for Shock Load Monitoring
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Solution Overview
Problem
Existing actuator assemblies in aircraft, particularly those with no-back devices, face challenges in monitoring health and functionality due to the inability to effectively counteract feedback forces and sudden changes in torque, leading to potential failures and damage.
Innovation Solution
The actuator assembly incorporates a load limiter and sensors to detect changes in rod length and load direction, allowing for real-time monitoring of torque and health status, and a resilient mechanism to absorb shocks and limit axial forces, thereby protecting the assembly and detecting performance issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a no-back device is provided to prevent feedback forces from rotating the screw shaft, then reliability is improved, but the device complexity increases
Solution Approach 1:
The no-back device is segmented into two separate braking mechanisms: a first braking mechanism for clockwise braking forces and a second braking mechanism for anticlockwise braking forces. This segmentation allows each mechanism to be simpler and more specialized, while collectively providing comprehensive protection against feedback forces in both rotation directions.
Solution Approach 2:
A rod is introduced as an intermediary element to react torque on the drive arrangement. The rod connects the drive arrangement to the airframe and transmits torque reactions, allowing the no-back device to function independently without directly complicating the screw shaft mechanism.
2Reliability
If braking forces are made sufficient to counteract maximum feedback torque, then reliability is improved, but the device complexity increases
Solution Approach 1:
The braking function is divided into two separate mechanisms, each handling one direction of rotation. This allows each mechanism to be optimized for a single direction, reducing individual complexity while ensuring sufficient braking force in both clockwise and anticlockwise directions.
Solution Approach 2:
Each braking mechanism is designed with specific local properties tailored to its function: the first braking mechanism is optimized for clockwise forces while the second is optimized for anticlockwise forces. This local specialization reduces overall complexity compared to a single universal braking mechanism.
3Adaptability or versatility
If the drive arrangement is pivotally supported to float about the screw shaft axis, then adaptability is improved, but the device complexity increases
Solution Approach 1:
The pivotal support functionality is merged with the torque reaction rod. The rod serves dual purposes: reacting torque on the drive arrangement and enabling pivotal movement. This combination reduces device complexity by eliminating separate pivotal support components.
Solution Approach 2:
The rod is designed as a multi-functional element that simultaneously reacts torque, allows pivotal movement, and provides a mounting structure for the drive arrangement. This universality reduces overall system complexity while maintaining adaptability.
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 solution enables continuous monitoring of the actuator's health and functionality, reducing the risk of failure and damage by absorbing sudden torque changes and providing a protective function, while also allowing for the computation of fatigue life consumption and endurance life consumption of components.
Implementation Method 1
a resilient mechanism to absorb shocks and limit axial forces, thereby protecting the assembly
Data Source
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AI summary
An actuator assembly may comprise a screw shaft having a shaft axis; a drive arrangement pivotally supported about the screw shaft axis for driving the screw shaft, e.g., about the shaft axis or along the shaft axis, and a rod mounted to the drive arrangement at a location off the shaft axis for providing a primary function of reacting torque about the shaft axis on the drive arrangement. The rod may comprise a rod axis and provide a load path along the rod axis for reacting torque. The rod may also comprise a device for which provides a secondary function for the actuator assembly based on the load experienced along the load path provided by the rod.