Blade-Retaining Plate With Internal Cut-Outs For Turbomachine Stator

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Solution Overview

Problem

Existing blade-retaining methods for axial turbomachine stators require high precision during assembly, are incompatible with narrow internal shells, and lack stability, leading to potential detachment during operation.

Innovation Solution

A blade-retaining member with a metallic structure featuring elastically deformable tongues that are integrally formed with the plate, providing a support surface for immobilization and orientation, simplifying assembly and enhancing stability by contacting the blade surfaces through an abradable layer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional V-shaped retaining pieces are used, then blade retention is improved, but the assembling member becomes very long and incompatible with narrow internal shells

Engineering Contradiction:

Improveblade retentionVSAvoidassembling member length

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The retaining piece is segmented into a plate portion and a finger portion that can be independently positioned. The plate is inserted into the cut-out while the finger extends between blades to provide retention, allowing the structure to fit within narrow shells without requiring excessive length.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The retention mechanism transitions from a purely axial V-shaped structure to a multi-dimensional configuration where the finger extends radially between blades. This dimensional change allows retention functionality to be achieved within a compact axial envelope suitable for narrow shells.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If manual positioning of V-shaped retaining pieces is used, then blade retention is achieved, but assembly precision requirements become very high

Engineering Contradiction:

Improveblade retentionVSAvoidassembly precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The finger is designed to automatically position itself between the blades during assembly. As the plate is inserted into the cut-out, the finger naturally extends and engages with the blade surfaces, eliminating the need for precise manual positioning of multiple components.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The finger acts as an intermediary element that mediates between the plate and the blades. It provides a simple engagement interface that naturally aligns with the blade surfaces, reducing the precision requirements for the overall assembly process.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Volume of moving object

If thin folding fingers are used, then retaining plate size is reduced, but the finger becomes weakened and positioning accuracy is lost

Engineering Contradiction:

Improveretaining plate sizeVSAvoidfinger strength

Core Design Contradiction:

Volume of moving objectVSStrength

Solution Approach 1:

The finger is designed with varying cross-sectional properties along its length. It is thinnest at the base where it joins the plate, gradually thickening toward the free end to provide maximum strength where it contacts the blades. This local quality variation optimizes both size reduction and strength retention.

Inventive Principle:

Principle #3Local quality

4Device complexity

If outward-pointing fingers are used, then retaining plate structure is simplified, but the finger tip position is uncontrolled and may contact rotor lip seals

Engineering Contradiction:

Improveretaining plate structureVSAvoidfinger tip positioning

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The finger is designed with a predetermined maximum extension position that prevents it from protruding beyond the abradable material layer. This preliminary design constraint ensures the finger tip cannot contact the rotor lip seals, preventing potential damage while maintaining structural simplicity.

Inventive Principle:

Principle #9Preliminary anti-action

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 solution improves the stability and positioning accuracy of the blade-retaining member, simplifies assembly, and reduces the size of the retaining member, eliminating the need for precise hooks and ensuring secure attachment even in narrow configurations.

Implementation Method 1

with elastically deformable tongues that are integrally formed with the plate, providing a support surface for immobilization and orientation

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS9771815B2Blade-retaining plate with internal cut-outs for a turbomachine stator

Publication Date: 2017.09.26 TECHSPACE AERO

AI summary

The invention relates to an axial turbomachine stator (2) comprising an inner shell (28) with an annular row of openings; an annular row of blades (26); the said blades extending substantially radially through the said openings, respectively, and each comprising a cut-out (34) on the inside of the shell; at least one blade-retaining plate (36) inserted in at least one cut-out (34), with means of immobilization of the said plate in the cut-out(s). The means of immobilization comprise at least one tongue (38) with an end forming a support surface (40) in contact with a part of the blade (26) or of one of the blades (26) located radially directly above the corresponding cut-out.