Titanium Threaded Aircraft Assembly to Prevent Galling
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Solution Overview
Problem
Aircraft assemblies require reduction in mass to enhance fuel efficiency while maintaining reliability and corrosion resistance, as existing assemblies are prone to galling due to thread interactions.
Innovation Solution
Incorporating a threaded insert made from a different metal with varying hardness into the titanium rod or nut to prevent galling, allowing for a majority of the assembly to be formed from titanium, thereby reducing weight and improving reliability through a cold forging thread rolling process and using materials like copper nickel tin alloys for enhanced corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If both the rod and nut are formed from titanium, then the assembly weight is minimized, but galling occurs between the threads reducing reliability
Solution Approach 1:
The patent applies local quality by inserting a hardness-modified section (either in the rod or nut) only at the thread engagement location. This localized modification prevents galling where threads contact while maintaining titanium material throughout the majority of the assembly, thus preserving weight efficiency while solving the reliability issue at the critical interface.
Solution Approach 2:
The patent uses composite materials by combining titanium with a hardness-modified section (such as steel or other metal inserts) within the rod or nut. This composite structure creates a multi-material assembly where the titanium provides weight efficiency and the hardness-modified section provides galling resistance at the thread interface, resolving the contradiction between weight and reliability.
2Reliability
If a hardness-modified insert is coupled to the rod or nut, then galling is prevented and reliability is improved, but the assembly complexity increases
Solution Approach 1:
The patent merges the hardness-modified insert with the titanium rod or nut into a single integrated component. Rather than using separate rod and nut components that are assembled, the hardness-modified section is combined with the titanium body through insertion or integration, creating a unified part that reduces assembly steps while maintaining the dual-material benefits for preventing galling.
3Weight of moving object
If titanium is used for both rod and nut, then weight is minimized, but corrosion resistance is reduced compared to stainless steel assemblies
Solution Approach 1:
The patent applies local quality by positioning the hardness-modified section (which can be made from corrosion-resistant materials like stainless steel or other metal alloys) at the thread engagement location. This localized use of alternative materials provides enhanced corrosion resistance at the critical interface where galling occurs, while the majority of the assembly remains titanium for weight efficiency.
Solution Approach 2:
The patent uses composite materials by combining titanium with corrosion-resistant metal inserts or hardness-modified sections made from materials like stainless steel, copper-nickel-tin alloys, or other corrosion-resistant alloys. This composite structure provides both weight efficiency from the titanium and enhanced corrosion resistance from the alternative material sections, resolving the contradiction between weight and corrosion resistance.
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 solution effectively reduces the weight of aircraft assemblies, enhances reliability by minimizing galling, and improves corrosion resistance, enabling the nut or rod to be formed predominantly from titanium with a metallic insert, thus improving the overall performance and efficiency of the assembly.
Implementation Method 1
the threads of the titanium threaded portion are formed by a cold forging thread rolling process
Implementation Method 2
The insert is formed from a metal having a different hardness in comparison to titanium in order to reduce the likelihood of galling as the nut is wound along the rod
Data Source
AI summary
An aircraft assembly having a titanium rod comprising a first threaded portion, and a titanium nut comprising a second threaded portion conforming with the first threaded portion for mating engagement with it. One of the first and second threaded portions defines a male thread and the other one of the first and second threaded portions defines a female thread such that the nut can be wound in threading engagement along the rod. A threaded insert formed from a first metal of different hardness in comparison to titanium is coupled to the rod or the nut to define the first threaded portion or the second threaded portion respectively such that one of the first and second threaded portions is formed from titanium and the other one of the first and second threaded portions is formed from the first metal.