Eccentric Actuator Connection for Thrust Reverser Anti-Buckling

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Solution Overview

Problem

Existing thrust reversers for turbojet aircraft nacelles face challenges in reducing drag and mass while preventing actuator buckling, as current solutions either increase the actuator's section size or require bulky structures that complicate integration and increase weight.

Innovation Solution

A thrust reverser system with a radially eccentric third connection between the actuator and the fixed structure, allowing for predetermined radial movement, which reduces bending moments and enables standardization of actuators for multiple applications, thereby minimizing weight and complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the actuator cross-section is increased to withstand bending forces, then the actuator strength is improved, but the mass of the thrust reverser increases

Engineering Contradiction:
Improveactuator strengthVSAvoidthrust reverser mass
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

A guide structure is introduced as an intermediary element between the actuator and the nacelle structure. This guide structure absorbs and redirects the bending forces, allowing the actuator to maintain a lighter cross-section while the overall system withstands the applied loads through the guide structure's force distribution mechanism

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The solution moves from purely strengthening the actuator in one dimension (increasing cross-section) to a multi-dimensional approach where the guide structure provides lateral support and force redistribution, effectively adding a spatial dimension to the load-bearing path

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

2Stability of the object's composition

If a drive rod-slide system is used to limit actuator bending, then the actuator stability is improved, but the device complexity and mass increase

Engineering Contradiction:
Improveactuator stabilityVSAvoidthrust reverser complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The guide structure is merged with existing structural elements of the thrust reverser system, such as the nacelle framework or actuator mounting points. This integration allows the guide function to be provided without adding separate, bulky components, thereby reducing overall device complexity while maintaining actuator stability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The guide structure serves multiple functions simultaneously: it guides the actuator movement, absorbs bending forces, and integrates with the existing structural framework. This multi-functionality eliminates the need for dedicated anti-buckling components, reducing complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Length of moving object

If actuators pass through openings in the fixed structure, then the radial displacement is limited, but the structural section must be increased to accommodate the actuators

Engineering Contradiction:
Improveradial displacement limitationVSAvoidfixed structure section
Core Design Contradiction:
Length of moving objectVSArea of stationary object

Solution Approach 1:

The fixed structure is segmented into distinct functional zones: the guide structure provides localized radial constraint at critical points, while other portions of the structure maintain their original cross-section. This segmentation allows radial displacement limitation without requiring the entire fixed structure to be oversized

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4077903B1Thrust reverser with Anti-buckling actuating system
Publication Date: 2024.10.02 SAFRAN NACELLES
  • EP4077903B1 patent drawingFigure 1~2a
  • EP4077903B1 patent drawingFigure 2b~4
  • EP4077903B1 patent drawingFigure 5a~5b

AI summary

The present application relates to a thrust reverser (1) for a turbojet aircraft nacelle, comprising: - a fixed structure (10), - a mobile structure (11), - an actuator (2) extending along a main axis (A1) and connected by a first connection (P1) to the fixed structure (10) and by a second connection (P2) to the mobile structure (11) for deploying the mobile structure (11) between a direct jet position and a reverse jet position, the actuator (2) being further connected to the fixed structure (10) by a third connection (P3) arranged longitudinally between the first connection (P1) and the second connection (P2), characterised in that: the axis (A3) of the third connection (P3) is radially eccentric from the main axis (A1), and in that the third connection (P3) enables a predetermined movement of the actuator (2) relative to the fixed structure (10).