Titanium Journal Support Pin With Hardened Surface for Weight Reduction
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Solution Overview
Problem
The weight of journal support pins in gas turbine engines is a concern due to their high stress volume and the use of heavy hardened steel, which compromises the weight reduction goal in gear reduction systems.
Innovation Solution
A journal support pin with a titanium body and an outer surface hardened to be harder than the body, utilizing a steel sleeve or coating such as silver, steel, or titanium nitride, and oil supply holes to reduce weight while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If hardened steel is used for journal support pins, then surface hardness and durability are improved, but weight increases
Solution Approach 1:
The journal support pin uses a composite structure combining titanium alloy body (for lightweight) with a hardened steel outer surface layer (for durability). This composite approach allows the pin to achieve both low weight and high surface hardness, resolving the contradiction between weight reduction and strength requirements.
Solution Approach 2:
The pin applies different material properties to different regions: the core is made of lightweight titanium alloy while the outer surface is hardened steel. This local differentiation allows the lightweight titanium body to reduce overall weight while the hardened outer layer provides the necessary surface hardness and wear resistance at the contact points.
2Weight of moving object
If titanium is used for journal support pins, then weight is reduced, but surface hardness decreases
Solution Approach 1:
The solution combines titanium alloy (providing lightweight properties) with a hardened steel outer layer (providing surface hardness). The titanium body maintains low weight while the steel coating restores the necessary surface hardness for durability under high stress conditions.
Solution Approach 2:
The pin structure implements local quality by having a titanium alloy core for weight reduction and a hardened steel outer surface for durability. This regional material differentiation ensures that hardness is concentrated where it is most needed at the contact surfaces while the bulk remains lightweight.
3Strength
If a steel sleeve is added to the titanium body, then surface hardness is improved, but device complexity increases
Solution Approach 1:
The steel sleeve forms a composite structure with the titanium body, where the sleeve is fitted over the titanium pin. This composite construction provides the necessary surface hardness through the steel layer while maintaining relative structural simplicity through a straightforward fit-over design.
Solution Approach 2:
The pin is segmented into two functional parts: a titanium alloy body for weight reduction and a separate steel sleeve for surface hardness. This segmentation allows each component to be optimized independently and assembled together, providing both required properties without excessive complexity.
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 allows for a lightweight titanium journal support pin with enhanced hardness and oil distribution, effectively reducing the overall weight of the gear reduction system while maintaining operational durability.
Implementation Method 1
the outer surface is provided by nitriding
Implementation Method 2
the outer surface is provided by a coating. The coating is one of silver, steel and titanium nitride
Implementation Method 3
oil supply holes extend from a central bore in the body through the surface
Data Source
AI summary
A journal support pin to support intermediate gears for use in gas turbine engine comprises a titanium body, and an outer surface outside of the titanium body having a surface hardness that is harder than the body. A gas turbine engine and a method of forming a journal support pin to support intermediate gears for use in gas turbine engine are also disclosed.