Single-Actuator Thrust Reverser Cowling to Prevent Jamming

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Solution Overview

Problem

Conventional actuation and guidance systems for grid-type thrust reversers in aircraft propulsion systems are complex, costly, and prone to synchronization issues due to multiple cylinders, leading to performance reduction and increased mass.

Innovation Solution

A simplified actuation system using a single actuator and main guide device, with optional auxiliary guide device, to control the external mobile structure, reducing the need for cylinder synchronization and system complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple cylinders are used to control the external mobile structure, then the structure can be actuated, but synchronization problems occur leading to increased complexity and mass

Engineering Contradiction:
Improvesynchronization reliabilityVSAvoidactuation system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges multiple cylinder functions into a single actuator that controls the external mobile structure through one piston rod. This eliminates the synchronization problems inherent in multi-cylinder systems while maintaining the actuation capability, directly resolving the technical contradiction between reliability and device complexity.

Inventive Principle:
Principle #5Merging (Combining)

2Manufacturing precision

If multiple cylinders with ball screws are used for synchronization, then positioning accuracy improves, but device complexity and cost increase

Engineering Contradiction:
Improvepositioning precisionVSAvoidguidance system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts the synchronization function from the actuation system by using a single actuator, eliminating the need for ball screws and complex guidance mechanisms. The positioning precision is maintained through the inherent single-point control architecture, resolving the contradiction between manufacturing precision and device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Ease of operation

If conventional multi-cylinder actuation is used, then the external structure can be moved, but parasitic forces damage the reversing gear

Engineering Contradiction:
Improveactuation capabilityVSAvoidreversing gear reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

By combining multiple cylinder functions into a single actuator, the patent eliminates parasitic forces that arise from synchronization errors in multi-cylinder systems. The single actuator provides uniform force distribution, protecting the reversing gear while maintaining full actuation capability.

Inventive Principle:
Principle #5Merging (Combining)

4Strength

If auxiliary guidance devices are added to limit deformations, then structural integrity improves, but device complexity increases

Engineering Contradiction:
Improvestructural integrityVSAvoidguidance system complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent takes out the need for auxiliary guidance devices by using a single actuator configuration that inherently limits deformations and maintains structural integrity. The simplified actuation architecture eliminates the requirement for additional guidance mechanisms, resolving the contradiction between strength and device complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4025781B1Thrust reverser comprising a single actuator for controlling a mobile cowling
Publication Date: 2026.01.28 SAFRAN NACELLES
  • EP4025781B1 patent drawingFigure 1~2
  • EP4025781B1 patent drawingFigure 3
  • EP4025781B1 patent drawingFigure 4

AI summary

The invention relates to a thrust reverser (20) for an aircraft propulsion assembly, this reverser (20) comprising a mobile annular external structure (22), a single actuator (25) for controlling the position of this mobile external structure (22) and a device for guiding (40) the mobile external structure (22) when changing its position. The actuator (25) and the guiding device (40) are housed in a fairing of a pylon of the propulsion assembly to a wing or fuselage of the aircraft.