Horizontal Stabilizer Actuator Screw Assembly for Backlash Detection
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Solution Overview
Problem
The existing technologies for detecting wear in the screw assembly of a trimmable horizontal stabiliser actuator, critical for aircraft safety, are inadequate in accurately measuring backlash or clearance, which can lead to nut failure if not properly monitored.
Innovation Solution
A screw assembly with features such as lugs and marks on the nut and stop that cooperate to visually or tactily indicate the amount of free movement between the nut and screw, allowing for easy detection of wear and alignment within acceptable limits, facilitating inspection and adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional wear detection methods are used, then inspection complexity is reduced, but measurement precision of backlash is insufficient
Solution Approach 1:
The screw assembly performs self-inspection through integrated visual features. The first feature on the nut and second feature on the stop automatically indicate backlash conditions without requiring external measurement instruments, enabling the component to self-diagnose its wear state.
Solution Approach 2:
The invention uses visual features that can be observed through color or visual differentiation. The first and second features are configured to present distinguishable visual states (such as alignment vs misalignment, different colors, or visible markers) that directly indicate the magnitude of backlash, enabling quick visual assessment.
2Measurement precision
If complex detection devices are used, then measurement precision improves, but ease of operation deteriorates
Solution Approach 1:
The screw assembly provides its own inspection mechanism through the cooperative first and second features. Inspectors can directly observe the relative positions of these features without needing to operate complex measurement devices, making the inspection process simple and intuitive while maintaining precise detection capability.
Solution Approach 2:
By using visually distinguishable features that change appearance or alignment based on backlash conditions, the invention enables inspectors to quickly assess free movement magnitude through simple visual observation rather than complex measurements, greatly improving ease of operation.
3Difficulty of detecting and measuring
If visual features are added to indicate wear, then detection capability improves, but device complexity increases
Solution Approach 1:
The visual features are integral parts of the existing nut and stop components rather than separate addition devices. The first feature on the nut and second feature on the stop work together as built-in indicators, eliminating the need for external detection equipment while improving wear detection capability.
Solution Approach 2:
The invention incorporates visual indicators (such as colored markers, contrasting materials, or alignment features) directly into the nut and stop structures. These features provide clear visual information about wear and backlash conditions without requiring complex additional components, thus improving detection capability with minimal increase in device complexity.
Data Source
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).