Double-Acting Linear Actuator for Turbojet Thrust Reverser

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Solution Overview

Problem

Existing actuation systems for thrust reversers in turbojet engines face difficulties in efficiently controlling a variable nozzle section during different flight phases, leading to increased mass, complexity, and cost, which negatively impact engine performance.

Innovation Solution

A double-action linear actuator design where a first and second tubular element are moved relative to a fixed element using a single drive motor, with the second drive shaft fixedly mounted on the first tubular element, allowing for simultaneous translational movement of both elements when locking means are unlocked, reducing the need for multiple drive chains.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple drive chains are used to control the variable nozzle section, then the actuation capability is improved, but the device complexity and mass increase

Engineering Contradiction:
Improveactuation capabilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines multiple drive chains into a single integrated drive mechanism. The first and second drive shafts are coupled such that one drive mechanism controls both the first tubular element (cowl) and the second tubular element (nozzle), reducing the number of independent drive systems from two to one while maintaining full actuation capability for both components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The single drive mechanism is designed to perform multiple functions: it can independently control the first tubular element (cowl) and the second tubular element (nozzle), and can also control them in a coupled manner. This multi-functional drive system replaces the need for separate dedicated drive chains for each component.

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

2Adaptability or versatility

If multiple drive chains are used to control the variable nozzle section, then the actuation capability is improved, but the mass increases

Engineering Contradiction:
Improveactuation capabilityVSAvoidsystem mass
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The patent merges multiple drive chains into a single integrated drive system, reducing the total mass of actuators, motors, and associated components. By controlling both the first and second tubular elements through one drive mechanism rather than two separate chains, the overall system mass is significantly reduced.

Inventive Principle:
Principle #5Merging (Combining)

3Manufacturing precision

If separate drive chains are used for each tubular element, then the control precision is improved, but the device complexity increases

Engineering Contradiction:
Improvecontrol precisionVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The single drive mechanism is segmented into multiple output paths: one path controls the first tubular element (cowl) and another path controls the second tubular element (nozzle). This segmentation within a unified system allows independent control of each component while avoiding the complexity of completely separate drive chains.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary coupling mechanism between the first and second drive shafts that allows coordinated control. This intermediary element enables the drive system to precisely control both tubular elements while maintaining a simplified single-chain architecture rather than requiring multiple independent chains.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2737231B1Double-acting linear actuator
Publication Date: 2015.11.04 AIRCELLE SA
  • EP2737231B1 patent drawingFigure 1~3
  • EP2737231B1 patent drawingFigure 4~6
  • EP2737231B1 patent drawingFigure 7

AI summary

The invention relates to a double-acting linear actuator (100) for moving a first element (10b) and a second element (10a) relative to a fixed element (17), said actuator comprising tubular elements mounted in series and locking means (120).