Engine Mounting Shackle Coating Encapsulation Against Edge Peeling
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Solution Overview
Problem
Aircraft engine fixing shackles with anti-friction coatings experience premature wear and peeling due to thermomechanical cycles, leading to reduced mechanical connection quality and increased maintenance costs.
Innovation Solution
The shackle design incorporates a ball joint with a sleeve and a ring, where the anti-friction coatings are encapsulated by projecting edges, forming a protective stop, and the coatings are made from materials like Copper Nickel Indium alloy or Cobalt alloy, enhancing longevity and reducing peeling phenomena.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anti-friction coatings are applied to the ball joint surfaces, then wear resistance is improved, but the coatings degrade and flake off at edges leading to peeling and delamination
Solution Approach 1:
The patent applies preliminary action by creating raised edges and protective stops during the manufacturing stage that prevent future coating degradation. The raised edges are formed on the ring and sleeve surfaces before coating application, creating a physical barrier that prevents peeling and delamination during subsequent thermomechanical cycling.
Solution Approach 2:
The patent segments the coating application area by creating distinct zones separated by raised edges. The first anti-friction coating is applied to a first zone on the ring with raised edges forming a protective stop, and the second anti-friction coating is applied to a second zone on the sleeve with similar protective edges, isolating each coating area to prevent edge-induced peeling.
2Reliability
If the shackle undergoes numerous thermomechanical cycles, then operational reliability is improved, but premature aging occurs due to coating degradation
Solution Approach 1:
The patent implements beforehand cushioning by incorporating protective stops and raised edges that cushion and protect the anti-friction coatings from thermomechanical stress during operational cycles. These structural features absorb and distribute the stress before it can reach the coating edges, preventing premature aging and degradation during repeated heating and cooling cycles.
3Reliability
If coating thickness is increased to improve wear resistance, then friction reduction is improved, but coating peeling and delamination are exacerbated
Solution Approach 1:
The patent applies local quality by creating non-uniform coating thickness distribution through the raised edges and protective stops. The coatings are applied to specific zones defined by these raised features, with the protective stops creating localized areas of controlled thickness that prevent edge peeling while maintaining adequate wear resistance in the contact zones.
Data Source
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AI summary
The invention relates to a shackle (100) for securing an aircraft engine, comprising a ball joint with a shaft (170) comprising: - a ring (110) having a first bore and a sleeve (120) assembled in the first bore and having a second bore configured to receive said shaft (170) and whose diameter gradually increases to present a flared inner surface at each of its ends, the shackle (100) being arranged such that: - a spherical outer surface of the ring (110) has an antifriction coating (111) applied over an area extending beyond its contact zone with the body of the shackle (100), this first zone being bordered by flanges (112) projecting around the coating (111), and/or - the second bore has an antifriction coating (121) applied over an area extending beyond its contact zone of contact with said axis (170),This area is bordered by raised edges (122) projecting around this anti-friction coating (121) at the ends of the flared inner surface. Advantageously, this increases the lifespan of anti-friction coatings by preventing peeling or flaking.