Elastomeric Bearing With Hollow End Cap for Rotor Weight Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Elastomeric bearings used in rotary wing aircraft require a balance between weight reduction and maintaining strength to withstand axial forces of over 20,000 pounds, as conventional materials like aluminum lack the necessary strength and titanium is cost-prohibitive.
Innovation Solution
The use of carbon fiber reinforced polyether ether ketone (PEEK) laminae and a partially hollow metal end cap formed via additive manufacturing, such as laser sintering, to create a lightweight yet robust elastomeric bearing that can support rotor blades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If aluminum layers are used to replace stainless steel layers, then weight is reduced, but strength is insufficient to withstand axial forces
Solution Approach 1:
The patent uses carbon fiber reinforced polyether ether ketone (CFR-PEEK) composite material for the laminae, combining carbon fiber reinforcement with PEEK matrix to achieve both weight reduction and high strength. This composite material provides the necessary mechanical properties to withstand axial forces of over 20,000 pounds while being significantly lighter than stainless steel.
Solution Approach 2:
The patent changes the material parameters by transitioning from metallic materials (stainless steel, aluminum) to composite materials (CFR-PEEK), altering the density-strength relationship. The CFR-PEEK material offers a favorable specific strength (strength-to-weight ratio) that enables weight reduction while maintaining load-bearing capacity.
2Weight of moving object
If titanium is used instead of stainless steel, then weight is reduced by about 40%, but cost becomes undesirably high
Solution Approach 1:
The patent employs CFR-PEEK composite material as an alternative to titanium, achieving similar weight reduction benefits while avoiding the high material and manufacturing costs associated with titanium. The composite material can be manufactured using conventional processes, reducing overall system cost.
Solution Approach 2:
The patent selects a material system (CFR-PEEK) that balances performance and cost, replacing expensive titanium while maintaining the required service life and performance characteristics for rotor support applications.
3Weight of moving object
If solid metal end cap is used, then strength is sufficient, but weight is excessive
Solution Approach 1:
The patent employs a metal end cap with a partially hollow interior structure, creating a porous or cellular configuration that reduces weight while maintaining structural integrity. The hollow interior removes unnecessary material from low-stress regions, achieving weight reduction without compromising the end cap's load-bearing capability.
Solution Approach 2:
The end cap is segmented into solid and hollow regions, with the hollow interior strategically positioned to reduce weight while the solid portions maintain structural strength. This segmentation allows optimization of the weight-strength trade-off in different regions of the end cap.
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
This configuration achieves a 30-40% weight reduction while maintaining the necessary strength to withstand centrifugal forces, matching the performance of stainless steel-based bearings at a lower cost.
Implementation Method 1
The metal end cap is formed by an additive manufacturing process, such as laser sintering
Data Source
AI summary
An elastomeric bearing includes a first race having an axis of rotation, a second race coaxially arranged relative to the first race and spaced from the first race by a gap, a bearing body in the gap connecting the first race to the second race, the bearing body comprising a plurality of first laminae coaxial with the first race and a plurality of second laminae coaxial with the first race, the first laminae being formed from a different material than the second laminae, and a metal end cap connected to the first race or to the second race. The metal end cap includes an at least partially hollow interior and/or is formed by an additive manufacturing process.