Thrust Reverser Rail Synchronization via Single Motor

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Solution Overview

Problem

Existing aircraft gas turbine thrust reverser systems with engine cowling designs are complex, costly, and prone to operational issues due to multiple actuating devices and synchronization challenges, especially under varying temperature and vibration conditions.

Innovation Solution

A telescopic rail arrangement with parallel toothed racks and a common motor-driven gear system ensures synchronized and reliable axial displacement of the engine cowling's rear region, eliminating the need for additional synchronization measures and reducing component complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple actuating devices and slide rail systems are used to displace the rear portion of the engine cowling, then the displacement function is achieved, but the device complexity and cost increase significantly

Engineering Contradiction:
Improveoperational reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple actuating devices into a single actuating device that can simultaneously displace the rear portion of the engine cowling along multiple parallel rails. This merging approach eliminates the need for separate actuators for each rail, thereby reducing device complexity while maintaining the ability to achieve reliable displacement of the thrust reverser components.

Inventive Principle:
Principle #5Merging (Combining)

2Manufacturing precision

If multiple actuating devices with synchronization systems are implemented, then uniform displacement is achieved, but the monitoring and maintenance effort increases

Engineering Contradiction:
Improveuniform displacementVSAvoidproduction and maintenance effort
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent uses a single actuating device to control the displacement of the rear cowling portion along multiple parallel rails, eliminating the need for complex synchronization systems between multiple actuators. This single-device approach inherently ensures uniform displacement while significantly reducing monitoring and maintenance requirements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent segments the displacement function into multiple independent parallel rails that can operate independently yet simultaneously, with each rail equipped with its own toothed rack. This segmentation allows the single actuating device to distribute force evenly across multiple rails, achieving uniform displacement without requiring complex inter-rail synchronization mechanisms.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If actuators are coupled to sliding devices with members slid off-line, then the thrust reverser can be actuated, but friction increases and jamming risk occurs

Engineering Contradiction:
Improvethrust reverser actuationVSAvoidfriction and jamming risk
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent employs a telescopic rail arrangement where the rails can extend and retract dynamically during operation. This dynamic configuration allows the rail elements to remain properly aligned with the toothed racks throughout the displacement range, maintaining optimal contact and minimizing friction while eliminating the jamming risk associated with fixed off-line sliding mechanisms.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This design enhances operational reliability, reduces weight and cost, and minimizes the risk of jamming by using a single drive element, ensuring uniform displacement and optimized torque handling with reduced noise and vibration.

Implementation Method 1

The gear wheel (6) is coupled to a common motor (8) via a gearbox (rack & pinion principle)

Methodology Applied
Scientific EffectRack and pinion mechanism: Rack and Pinion

Implementation Method 2

A gear or pinion is engaged with each rack to move the rack relative to the rail

Methodology Applied
Scientific EffectGear meshing: Gear

Data Source

PatentEP2886843B1Aviation gas turbine having an engine cowl with thrust reverser
Publication Date: 2017.07.19 ROLLS ROYCE DEUT LTD & CO KG
  • EP2886843B1 patent drawingFigure 1
  • EP2886843B1 patent drawingFigure 2
  • EP2886843B1 patent drawingFigure 3

AI summary

The present invention relates to an aircraft gas turbine with an engine cowling 2, the rear section 3 of which, in the direction of flow, is provided with a thrust reverser device, wherein the rear section 3 is designed to be axially displaceable, characterized in that the rear section 3 is slidably mounted on two mutually parallel rails 4 and each comprises a rack 5 mounted on each rail 4, which is in engagement with a gear 6, which is coupled to a common motor 8 via a gearbox 7.