Horizontal Stabiliser Actuator Screw Assembly for Freeplay Detection
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Solution Overview
Problem
Existing methods for detecting wear in the screw assembly of a trimmable horizontal stabiliser actuator are inadequate, particularly in determining free movement or backlash, which is critical for safety and precision.
Innovation Solution
Incorporating visual or tactile features such as lugs and marks on the nut and stop components that align or fail to align based on the amount of free movement, allowing for easy visual inspection to determine if wear is within acceptable limits, with adjustable positions to accommodate varying clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional wear detection methods are used, then detection capability is insufficient, but adding complex detection features increases device complexity
Solution Approach 1:
The screw assembly performs self-detection of wear through its own structural features. The first and second features on the screw and nut respectively enable the assembly to detect its own wear condition without external detection equipment, making the system self-diagnosing while maintaining simplicity
Solution Approach 2:
The invention uses visual features (marks, notches, or protrusions) that can be observed to indicate wear conditions. These features provide visual feedback about the wear state of the screw assembly, enabling easy inspection without complex instrumentation
2Measurement precision
If free movement measurement requires precise instrumentation, then measurement precision improves, but ease of operation deteriorates
Solution Approach 1:
The screw assembly provides its own measurement reference through the relative positions of the first and second features. These features serve as built-in indicators that enable inspection of free movement without requiring external measurement instruments or complex procedures
Solution Approach 2:
Visual features such as marks, notches, or protrusions are used to indicate the relative position between screw and nut. These visual indicators allow inspectors to easily assess free movement conditions through simple visual inspection rather than complex measurement procedures
3Reliability
If wear detection features are added to the screw assembly, then reliability improves, but device complexity increases
Solution Approach 1:
The screw assembly incorporates self-detection capabilities through integrated features rather than adding separate detection systems. The first feature on the screw and second feature on the nut work together as part of the existing assembly structure, providing wear detection without requiring additional independent components
Solution Approach 2:
Visual indicators such as marks, notches, or protrusions are incorporated into the existing screw and nut structures. These features provide reliable wear detection through visual inspection while maintaining compatibility with the existing actuator design and not requiring fundamental structural changes
Data Source
Figure 1
Figure 2A~2C
Figure 3
AI summary
A screw (20) assembly for an actuator (10) is described comprising: a screw (20); a nut (22) threaded on said screw (20), such that rotation of said screw (20) causes axial movement of said nut (22); a stop located at an end of said screw (20) and defining an axial limit of said nut (22); a first feature located on said nut (22); and a second feature located on said stop; wherein said first and second features are configured to cooperate with one another substantially upon contact of said nut (22) with said stop so as to indicate an amount of free movement between said nut (22) and said screw (20).