Wear-Resistant Stilt Coating for Turbojet Fan Blade Supports

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Solution Overview

Problem

The premature wear of the rear surfaces of the stilt in aircraft turbojet fan blades due to friction during autorotation phases leads to mechanical weakness and increased risk of blade breakage, exacerbated by oscillation and potential impact from adjacent blades.

Innovation Solution

An anti-wear part is applied to the rear surfaces of the stilt, made from a nickel-chromium-iron alloy or composite material, which reduces friction and oscillation amplitude by forming a protective veil between the stilt surfaces and the mounting flanges, preventing direct contact and wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the stilt is designed with reduced thickness to cross the cell opening, then the blade assembly is enabled, but premature wear occurs on the rear surfaces of the stilt due to friction during autorotation

Engineering Contradiction:
Improvestilt thicknessVSAvoidwear resistance
Core Design Contradiction:
Length of moving objectVSReliability

Solution Approach 1:

The patent applies a ceramic coating (composite material) on the rear surfaces of the stilt to create a wear-resistant layer. This composite structure combines the metallic stilt base with the ceramic protective layer, providing both mechanical strength and wear resistance without increasing the overall thickness of the stilt.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The patent changes the surface properties of the stilt by applying a ceramic coating, which modifies the friction and wear characteristics of the rear surfaces. This parameter change allows the stilt to maintain its reduced thickness while significantly improving its wear resistance during autorotation phases.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If play is provided between the stilt and fastening flanges, then blade assembly is facilitated, but oscillation amplitude increases during autorotation causing accelerated wear

Engineering Contradiction:
Improveblade assemblyVSAvoidblade service life
Core Design Contradiction:
Ease of operationVSDuration of action of moving object

Solution Approach 1:

The ceramic coating on the stilt surfaces reduces friction during oscillation, allowing the necessary play for assembly while minimizing the harmful effects of oscillation during autorotation. The low-friction surface extends the service life despite the continued presence of play.

Inventive Principle:
Principle #40Composite materials

3Device complexity

If the stilt surfaces directly contact the fastening flanges, then structural simplicity is maintained, but mechanical strength decreases due to wear indentations

Engineering Contradiction:
Improvestructural complexityVSAvoidmechanical resistance
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The ceramic coating creates a protective barrier that prevents wear indentations from forming on the metallic stilt surfaces. This composite structure maintains the simple overall design while protecting the mechanical strength of the stilt during operation.

Inventive Principle:
Principle #40Composite materials

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 anti-wear part enhances the mechanical strength of the stilt and blade, reduces wear, and minimizes the risk of blade breakage by limiting oscillation and contact with mounting flanges, extending the blade's lifespan and reducing maintenance needs.

Implementation Method 1

this wear resulted from friction between these surfaces and their facing mounting flange

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2564031B1Wear-resistant part for the support of a blade of a turbojet engine fan
Publication Date: 2017.06.07 SN DETUDE & DE CONSTR DE MOTEURS DAVIATION (S N E C M A)
  • EP2564031B1 patent drawingFigure 1
  • EP2564031B1 patent drawingFigure 2~3
  • EP2564031B1 patent drawingFigure 4~5a

AI summary

The present invention relates to a turbojet engine fan for an aircraft, including a plurality of fan blades (10), the supports (13) of which comprise a rear portion including a first surface (13a) located on the pressure side, and a second surface (13b) located on the suction side. The fan disk (2) includes, between the recesses (8), fastening flanges (26) projecting radially outward, such that the first and second surfaces (13a, 13b) are located opposite two of the fastening flanges (26, 26), respectively. According to the invention, the fan comprises a wear-resistant part (40) mounted on each blade so as to form a protective web (32a, 32b) on each of the first and second surfaces (13a, 13b) of the support, thus preventing contact between each surface (13a, 13b) and the fastening clip (26, 26) opposite which said surface is located.