Rotor Abutment Mechanism with Elastomer Spacer for Composite Hub
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Solution Overview
Problem
Existing rotorcraft rotors with hubs made of composite materials face challenges in accommodating dimensional dispersions and complex shapes, leading to difficulties in installing metal abutments and risking local delamination due to impact forces during lead/lag movement.
Innovation Solution
A rotor with an abutment mechanism comprising an elastomer spacer strip and metal clips, where the elastomer strip is flexible and easy to install, accommodating dimensional variations and distributing impact forces to prevent delamination, and featuring reversible fastening for adaptability and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal abutments are installed on composite material hubs, then lead/lag movement can be limited, but installation becomes difficult due to dimensional dispersions and complex hub shapes
Solution Approach 1:
The patent changes the material parameter from rigid metal to flexible elastomer, allowing the abutment to adapt to dimensional variations in composite hubs while maintaining its lead/lag limiting function. The elastomer's elasticity enables it to deform and conform to the complex hub geometry during installation and operation.
Solution Approach 2:
The patent employs composite construction by combining elastomer material with a metallic reinforcement cage. This composite structure provides both the flexibility needed to accommodate hub dimensional variations and the structural integrity required to limit lead/lag movement effectively.
2Reliability
If metal abutments are used to limit lead/lag movement, then hub protection is provided, but impact forces cause local delamination of composite material hubs
Solution Approach 1:
The patent changes the mechanical property parameter from rigid to flexible by using elastomer material. This flexibility allows the abutment to absorb impact forces through deformation rather than transmitting concentrated loads to the composite hub, thereby preventing local delamination while maintaining protective function.
Solution Approach 2:
The elastomer abutment acts as an intermediary element between the lift assembly and the composite hub. It mediates the impact forces by deforming elastically, distributing the load over a larger area and time period, thus protecting the vulnerable composite hub structure from delamination.
3Reliability
If rigid abutment structures are used, then lead/lag movement is effectively limited, but adaptability to different hub shapes and dimensions is reduced
Solution Approach 1:
The patent changes the physical state parameter from rigid to elastic by using elastomer material. This enables the abutment to adapt its shape to various hub geometries while maintaining sufficient structural integrity to limit lead/lag movement, achieving both effectiveness and versatility.
Solution Approach 2:
The patent employs a flexible elastomer structure that can deform and conform to different hub shapes and sizes. This flexible design maintains the abutment's functional integrity across various configurations, enhancing adaptability to different hub geometries while preserving movement limitation capability.
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 abutment mechanism effectively limits lead/lag movement, distributes impact forces, and prevents delamination of composite material hubs, while being simple and cost-effective, suitable for various hub shapes and dimensions.
Implementation Method 1
an elastomer spacer strip having a central section extending transversely from a first base to a second base along said edge face
Implementation Method 2
distributing impact forces to prevent delamination
Data Source
AI summary
A rotor having a hub and a plurality of lift assemblies, the rotor having one lead/lag abutment mechanism per lift assembly. Each abutment mechanism includes an elastomer spacer strip and two C-shaped metal clips engaged respectively on a first base and on a second base of the strip. Two fastener pins each pass through a clip and the longitudinal projections of a base and through an orifice in the hub.