Aircraft Jet Engine Intermediate Casing Bosses Structural Arms

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Solution Overview

Problem

The existing designs for intermediate casings in turbojet engines are complex and mass-intensive due to the high thrust forces they need to manage, leading to congestion and inefficiencies in the space between flanges.

Innovation Solution

The intermediate casing design incorporates bosses extending from the rear flange to contact structural arms, allowing for a direct and efficient path for thrust forces, along with a reinforcing rib for shearing forces, simplifying the structure and reducing mass.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the intermediate casing is designed with complex structure to handle high thrust forces, then the strength and reliability are improved, but the mass and device complexity increase

Engineering Contradiction:
Improvethrust force handling capabilityVSAvoidintermediate casing structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The intermediate casing is divided into a modular structure comprising a front flange, rear flange, and multiple structural arms arranged radially between them. This segmentation allows each component to be optimized independently for its specific function while collectively handling thrust forces efficiently.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The bosses are integrated directly into the rear flange structure, merging the force transfer function with the flange itself. This eliminates the need for separate reinforcing structures and reduces overall complexity while maintaining strength.

Inventive Principle:
Principle #5Merging (Combining)

2Strength

If the intermediate casing is designed with complex structure to handle high thrust forces, then the strength and reliability are improved, but the mass increases

Engineering Contradiction:
Improvethrust force handling capabilityVSAvoidintermediate casing mass
Core Design Contradiction:
StrengthVSWeight of stationary object

Solution Approach 1:

The modular structure with discrete structural arms allows material to be placed only where structurally necessary, reducing unnecessary mass while maintaining strength for thrust force handling.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Integrating bosses directly into the rear flange eliminates separate components and reduces overall mass while maintaining the force transfer path capability.

Inventive Principle:
Principle #5Merging (Combining)

3Area of stationary object

If the fixing fittings are positioned close to the rear flange to save space, then the space utilization is improved, but the structural complexity and mass increase due to high thrust forces

Engineering Contradiction:
Improvespace between flangesVSAvoidrear flange structure complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The bosses are merged with the rear flange structure, allowing fixing fittings to be positioned close to the flange without requiring additional complex structural elements. The integrated design handles high thrust forces efficiently in the limited space.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP2072396B1Intermediate casing for an aircraft jet engine with improved design
Publication Date: 2014.07.16 SN DETUDE & DE CONSTR DE MOTEURS DAVIATION (S N E C M A)
  • EP2072396B1 patent drawingFigure 1~2
  • EP2072396B1 patent drawingFigure 3~4
  • EP2072396B1 patent drawingFigure 5~6

AI summary

The invention relates to an intermediate casing (21) for an aircraft turbojet engine, comprising an outer shell (23) and front and rear flanges (25, 27) arranged radially internally with respect to the outer shell. The casing (21) also includes structural arms (17) extending radially between the flanges to the shell (23). The rear flange is equipped with receiving means (34) for a fitting to secure a thrust-response connecting rod. The first receiving means comprise bosses (36) extending from the rear flange, through which are formed through holes (38) through which are threaded screws for securing the fitting. According to the invention, at least one of the bosses (36) extends to contact one of the structural arms (17).