Nested Ball Nut Assembly for Visual Fault Inspection
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Solution Overview
Problem
Existing aircraft actuation systems with ball screw assemblies face challenges in visually identifying component failures due to internal redundancy configurations, leading to increased complexity, reliability, and cost concerns.
Innovation Solution
The design incorporates a ball nut with multiple arms and nut members that provide visual access to all outer surfaces, allowing for the detection of faults and incorporating redundant load paths and locking arrangements to ensure continued functionality in case of primary path failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant ball nut arrangements are used with internal components, then reliability is improved through backup components, but visual accessibility and inspection capability deteriorate
Solution Approach 1:
The patent implements a nested ball nut arrangement where a secondary ball nut is positioned within the primary ball nut. The secondary nut contains backup components that are visually accessible through openings in the primary nut's outer surface. This nesting approach allows redundant components to be housed compactly while maintaining inspection capability through strategically placed openings that expose critical surfaces for visual detection of faults.
2Reliability
If redundant ball nut arrangements with enclosures are used, then reliability is improved through backup components, but device complexity increases
Solution Approach 1:
The patent merges the primary and secondary ball nuts into a single integrated assembly where the secondary nut is positioned within the primary nut. This combining approach eliminates the need for separate enclosures and reduces overall structural complexity while maintaining redundant functionality. The arms of both nuts extend radially outward to provide visual access, further simplifying the design by eliminating additional access mechanisms.
3Reliability
If internal redundancy components are used, then reliability is improved through backup components, but inspection complexity and cost increase
Solution Approach 1:
The patent extracts key inspection surfaces of the secondary ball nut through openings in the primary nut's outer surface. This extraction approach allows critical components to be visually accessible without requiring disassembly or complex inspection procedures. The openings are strategically positioned to expose arm surfaces and other critical areas, enabling straightforward visual inspection that reduces both inspection complexity and associated costs.
Data Source
AI summary
An actuator includes a drive assembly, a ball screw, and a ball nut. The ball nut may include a first nut member, a second nut member; and first arm extending from the first nut member. The first arm may include a first portion and a second portion. The first portion may extend radially outward from the first nut member. The second portion may extend substantially axially from the first portion such that at least some of the second portion is disposed radially outward of the second nut member. A second arm may extend from the second nut member, and the second arm may include a first portion and a second portion. In embodiments, at least part of the second portion of the first arm is disposed radially outward of at least a part of the second portion of the second arm.