Tangential Connecting Rods for Aircraft Engine Casing Deformation Control

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Solution Overview

Problem

Existing engine assemblies for aircraft turbojet engines experience deformations due to suboptimal arrangement of connecting rods, leading to undesirable mechanical stresses and inefficiencies in force transmission between the annular structure and central casing.

Innovation Solution

The engine assembly optimizes the mechanical junction by arranging connecting rods tangentially with respect to the central casing, placing force introduction points and connecting rod ends in the same radial fictitious plane, and incorporating reinforcing structures to absorb forces and limit deformations, allowing for better thermal expansion management and reduced ovalization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If connecting rods are arranged in a conventional non-optimized configuration, then the mechanical junction between annular structure and central casing is simpler to implement, but deformations of the annular structure and central casing increase due to suboptimal force transmission

Engineering Contradiction:
Improvedeformation control of annular structure and central casingVSAvoidarrangement complexity of connecting rods
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by optimizing the arrangement of connecting rods at specific locations around the annular structure. Each connecting rod is positioned to align with its corresponding force introduction point in the radial fictitious plane, creating locally optimized force transmission paths that reduce deformations at critical areas while maintaining overall structural integrity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent introduces a new dimensional concept by defining radial fictitious planes that pass through the longitudinal axis and each force introduction point. This dimensional approach allows the connecting rods to be arranged in three-dimensional space optimally, aligning them with the force vectors while maintaining tangential orientation relative to the central casing, thereby resolving the contradiction between simplicity and precision.

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

2Stability of the object's composition

If connecting rods are arranged tangentially with respect to the central casing, then deformations are reduced and mechanical stability is enhanced, but the complexity of the mechanical junction increases

Engineering Contradiction:
Improvemechanical stability of engine assemblyVSAvoidcomplexity of mechanical junction
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent employs asymmetry by arranging connecting rods in a non-uniform pattern around the annular structure. Each connecting rod is positioned asymmetrically to align with its specific force introduction point, creating optimized force transmission paths that enhance mechanical stability while avoiding the need for symmetric but less effective arrangements.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent applies preliminary action by pre-aligning the connecting rods with the force introduction points during the design phase. The radial fictitious planes are defined in advance to determine the optimal positions of connecting rods, ensuring that force transmission is optimized before the engine operates, thereby enhancing stability without requiring complex real-time adjustments.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If force introduction points and connecting rod ends are placed in the same radial fictitious plane, then force transmission efficiency is improved and deformations are limited, but the design and manufacturing precision requirements increase

Engineering Contradiction:
Improveforce transmission efficiencyVSAvoidprecision of force introduction point alignment
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent creates equipotential conditions by ensuring that force introduction points and connecting rod ends lie in the same radial fictitious plane. This alignment equalizes the force transmission path, eliminating inefficiencies caused by misalignment and ensuring optimal force transfer from the annular structure to the central casing through the connecting rods.

Inventive Principle:
Principle #12Equipotentiality

4Strength

If reinforcing structures are added to absorb forces and limit deformations, then mechanical stability and deformation resistance are improved, but the device complexity and weight increase

Engineering Contradiction:
Improvedeformation resistance of annular structureVSAvoidstructural complexity of engine assembly
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the reinforcing function into multiple discrete connecting rods distributed around the annular structure. Each connecting rod acts as an independent reinforcement element, absorbing forces and limiting deformations at specific locations. This segmented approach provides effective reinforcement while maintaining modularity and avoiding the need for a single complex reinforcing structure.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2244943B1Aircraft engine assembly comprising an annular load-transfer structure surrounding the central casing of a turbojet engine
Publication Date: 2019.07.03 AIRBUS OPERATIONS (SAS)
  • EP2244943B1 patent drawingFigure 1~2
  • EP2244943B1 patent drawingFigure 3
  • EP2244943B1 patent drawingFigure 4

AI summary

The invention relates to an aircraft engine assembly comprising an annular load-transfer structure surrounding the central casing (16) and connected to a plurality of substantially planar structures arranged externally with respect to this annular structure, and acting upon it at a plurality of load application points (68a, 68b, 68c). According to the invention, at least one connecting link is associated with each of the load application points, the said link being positioned tangentially with respect to the casing (16) and having an inner end (62a) connected to this casing and an outer end (62b) connected to the structure (60) so that it has passing through it an imaginary plane (66a, 66b, 66c) in which said structure is located and which passes through the load application point.