Radial Strut Connection Using Interleaving Inserts

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Solution Overview

Problem

The existing connection designs between radial arms and outer shrouds in turbomachines face challenges such as difficult assembly, excessive stress on assembly components, and potential seizing of bolts, leading to issues with structural integrity and precision during assembly and operation, especially under high temperatures and forces.

Innovation Solution

The connection design incorporates side wings on the radial arms, wedges, and centering pins, with bolts passing through aligned holes in the outer shroud and wedges, allowing for precise positioning and decoupling of forces, ensuring stability and easy assembly despite limited access.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If classic assembly with single ear and bolt is used, then assembly is simple, but bolt is loaded in bending requiring larger connection parts

Engineering Contradiction:
Improveassembly structureVSAvoidbolt loading
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The patent uses asymmetric ear configurations where one ear is positioned closer to the arm end than the other, creating an asymmetric loading pattern that reduces bending moments on the bolt while maintaining structural integrity

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent introduces a third dimension by positioning ears at different radial distances from the arm end, transforming the simple planar bolt connection into a three-dimensional structure that distributes forces more effectively and reduces bending loads

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Ease of operation

If lugs are spread apart for easy assembly, then assembly is easy, but bolt undergoes significant shearing and bending

Engineering Contradiction:
Improveassembly easeVSAvoidbolt stress
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent employs asymmetric ear positioning where ears are placed at different distances from the arm end, creating an asymmetric configuration that facilitates easy assembly while distributing bolt loads more evenly to reduce shearing and bending stresses

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent introduces intermediate positioning features such as alignment pins and tapered guide surfaces that mediate the assembly process, enabling easy insertion of the arm while ensuring proper positioning of the ears to optimize bolt loading conditions

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If lugs are brought closer together, then play is reduced and bending disappears, but assembly becomes difficult requiring helical movement

Engineering Contradiction:
Improveassembly precisionVSAvoidassembly difficulty
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent incorporates preliminary alignment features such as alignment pins,定位 surfaces, and tapered guide surfaces that are provided before the final assembly step, enabling the arm to be precisely positioned and inserted without requiring complex helical movements

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent uses three-dimensional positioning features including ears at different radial positions and axial offsets, transforming the assembly from a simple planar insertion to a multi-dimensional positioning that facilitates precise alignment while maintaining easy assembly through optimized spatial arrangement

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

4Strength

If bolts are used for connection, then connection strength is achieved, but bolts may seize up under high temperatures

Engineering Contradiction:
Improveconnection strengthVSAvoidbolt seizing
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent introduces intermediary elements such as heat-resistant washers, thermal barriers, and coated surfaces between the bolt and connected parts, mediating the thermal interaction to prevent bolt seizing while maintaining connection strength under high temperature conditions

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the material parameters of the connection components by selecting heat-resistant materials, applying thermal coatings, or using composite structures that change their properties under temperature to maintain connection integrity and prevent bolt seizing in high temperature environments

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2058476B1Connection of radial struts to a circular casing by interleaving inserts
Publication Date: 2013.08.07 SN DETUDE & DE CONSTR DE MOTEURS DAVIATION (S N E C M A)
  • EP2058476B1 patent drawingFigure 1~4
  • EP2058476B1 patent drawingFigure 5~8
  • EP2058476B1 patent drawingFigure 9~11

AI summary

The connection of an arm to a ferrule is achieved by interlocking a lateral wing (21,23) projecting from the end of the arm (10) and shims (22) bolted to the ferrule (11). The assembly is completed by positioning pins (30).