Propeller Blade Retention Element With Hardened Corrosion-Resistant Races

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Solution Overview

Problem

Propeller blade retention elements made from corrosion-resistant metals face a challenge in maintaining corrosion resistance after hardening processes like carburization, which are used to increase the hardness of bearing races, leading to potential wear issues.

Innovation Solution

The use of corrosion-resistant, hardenable materials like stainless steels for the bearing race portions, which are friction welded and induction hardened, allowing for retention of corrosion resistance while achieving the necessary hardness for the bearing races.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If carburization is applied to harden bearing races, then wear resistance is improved, but corrosion resistance deteriorates

Engineering Contradiction:
ImprovehardnessVSAvoidcorrosion resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The retention element is divided into two distinct parts: a body portion made from corrosion resistant metal and a bearing race portion made from hardenable metal. This segmentation allows each part to have optimized properties for its specific function while being part of a unified component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the retention element have different material properties. The body portion uses corrosion resistant metal for chemical stability, while the bearing race portion uses hardenable metal for wear resistance. This local differentiation of material quality resolves the contradiction between hardness and corrosion resistance.

Inventive Principle:
Principle #3Local quality

2Strength

If metal retention elements are used for structural strength, then mechanical strength is improved, but corrosion resistance deteriorates after hardening

Engineering Contradiction:
Improvemechanical strengthVSAvoidcorrosion resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The retention element combines two different metals with complementary properties: corrosion resistant metal for the body and hardenable metal for the bearing races. This composite construction achieves both mechanical strength and corrosion resistance by leveraging the strengths of each material in appropriate locations.

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

This solution ensures that the propeller blade retention elements maintain effective corrosion resistance and hardness, preventing wear and extending the lifespan of the components.

Implementation Method 1

The bearing race portion is friction welded to the body portion

Methodology Applied
Scientific EffectFriction welding: Friction Welding

Implementation Method 2

The bearing race portion is induction hardened

Methodology Applied
Scientific EffectInduction hardening: Induction Heating

Data Source

PatentEP3431388B1Propeller blades
Publication Date: 2024.08.28 RATIER FIGEAC SAS
  • EP3431388B1 patent drawingFigure 1
  • EP3431388B1 patent drawingFigure 2~4
  • EP3431388B1 patent drawingFigure 5

AI summary

A propeller blade retention element (6) comprises a body portion (40) formed of a corrosion resistant metal, and at least one bearing race portion (42) attached to the body portion (40), the race portion (42) being formed of an induction hardenable, corrosion resistant metal.