Overmolded Vane Platform Weight Reduction

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Solution Overview

Problem

The cumulative weight of guide vane end fittings and fasteners in gas turbine engines is significant, and existing solutions fail to provide the necessary aerodynamic flow path and resistance to foreign object damage while minimizing weight and manufacturing complexity.

Innovation Solution

The method involves overmolding a thermoplastic sheath around a metallic fixture to create a lightweight, aerodynamically optimized vane structure that reduces weight and maintains structural integrity, using a 'bone-shaped' base with apertures for fasteners and an airfoil-shaped vane mount for improved fatigue resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional metallic fittings and fasteners are used for guide vanes, then structural strength and durability are ensured, but the cumulative weight becomes significant

Engineering Contradiction:
Improvestructural strengthVSAvoidcumulative weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The guide vane assembly uses a composite structure combining a metallic fixture (for structural strength and fastener mounting) with an overmolded thermoplastic aerodynamic sheath (for weight reduction and aerodynamic performance). This composite approach maintains the necessary mechanical strength while significantly reducing the overall weight compared to traditional all-metallic constructions.

Inventive Principle:
Principle #40Composite materials

2Reliability

If complex vane end fitting interfaces are designed to provide aerodynamic flow path and withstand mechanical loads, then performance is improved, but manufacturing complexity increases

Engineering Contradiction:
Improveaerodynamic performance and durabilityVSAvoidvane end fitting interface complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges multiple functions into a single integrated fixture structure: the metallic fixture serves as both the structural support element and the mounting interface for fasteners, while the overmolded thermoplastic sheath provides the aerodynamic flow path. This integration eliminates the need for separate complex interfaces, reducing manufacturing complexity while maintaining reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The use of thermoplastic material with specific molding parameters allows the aerodynamic sheath to be directly formed over the fixture, creating a seamless integration that simplifies the interface design. The molding process parameters enable the thermoplastic to conform precisely to the fixture geometry, achieving complex aerodynamic shapes without complex manufacturing steps.

Inventive Principle:
Principle #35Parameter changes

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 approach reduces the weight of the vane structure, minimizes aerodynamic losses, and enhances resistance to foreign object damage, while maintaining the required structural and aerodynamic performance.

Implementation Method 1

A method of making an aerodynamic structure includes providing a fixture and molding a thermoplastic aerodynamic sheath about the fixture. The molding process involves heating the thermoplastic material to its melting point, injecting it into the mold cavity, and allowing it to cool and solidify, forming the aerodynamic sheath that encapsulates the fixture.

Methodology Applied
Scientific EffectMelting and solidification: Melting

Data Source

PatentEP2932049B1Overmolded vane platform
Publication Date: 2020.11.04 RTX CORP
  • EP2932049B1 patent drawingFigure 1
  • EP2932049B1 patent drawingFigure 2
  • EP2932049B1 patent drawingFigure 3

AI summary

A vane includes a platform with a fixture overmolded by a sheath.