Reverse Thrust Actuation System Locking Mechanism

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Solution Overview

Problem

Current actuation systems for variable nozzle thrust reversal devices in turbojet engines are complex, time-consuming, and degrade acoustic performance due to the need for multiple locking and unlocking maneuvers during thrust reversal and nozzle section variation.

Innovation Solution

A simplified actuation system with dual-state locking means for the nozzle and cowl, allowing for independent movement and locking of the nozzle panels, and a single-action actuator that controls the cowl and nozzle panels, eliminating the need for nozzle reclosure during thrust reversal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple locking and unlocking maneuvers are used during thrust reversal and nozzle section variation, then the nozzle and cowl can be securely locked in different positions, but the actuation time increases and acoustic performance deteriorates

Engineering Contradiction:
Improvelocking reliabilityVSAvoidactuation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent combines the locking of the nozzle panel and the cowl into a single integrated locking mechanism. The locking means simultaneously lock both the nozzle panel in its retracted position and the cowl in its open position during thrust reversal, eliminating the need for separate sequential locking operations. This merging of locking functions reduces the number of maneuvers required while maintaining secure positioning of both components.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If multiple locking and unlocking maneuvers are used during thrust reversal and nozzle section variation, then the nozzle and cowl can be securely locked in different positions, but the acoustic performance is reduced

Engineering Contradiction:
Improvelocking reliabilityVSAvoidacoustic performance
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent merges the locking operations into a single simultaneous action. The locking means are designed to lock both the nozzle panel and the cowl in their respective positions during thrust reversal in one operation, rather than requiring multiple sequential locking maneuvers. This reduction in the number of maneuvers minimizes disturbances to the air flow and prevents degradation of acoustic performance.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If a single-action actuator is used to control both cowl and nozzle panels, then the device complexity is reduced, but the control of independent movement becomes more difficult

Engineering Contradiction:
Improveactuation system complexityVSAvoidindependent movement control
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The patent segments the actuation system into two independent but coordinated actuation means: a first actuation means for moving the nozzle panel between retracted and extended positions, and a second actuation means for moving the cowl between closed and open positions. This segmentation allows each component to be controlled independently when needed, while the overall system remains simpler than fully integrated multi-action actuators would require.

Inventive Principle:
Principle #1Segmentation

4Object-affected harmful factors

If the nozzle is not reclosed during thrust reversal, then the acoustic performance is maintained, but the control of thrust reversal becomes less precise

Engineering Contradiction:
Improveacoustic performanceVSAvoidthrust reversal control precision
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent employs locking means that are pre-positioned to engage and lock the nozzle panel in its retracted position and the cowl in its open position simultaneously during thrust reversal. This preliminary positioning and locking mechanism ensures precise control of the thrust reversal operation without requiring the nozzle to be reclosed, thereby maintaining acoustic performance while achieving accurate control.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2577032B1Assembly including a reverse thrust device and system for actuating said device
Publication Date: 2018.10.31 SAFRAN NACELLES
  • EP2577032B1 patent drawingFigure 1~4
  • EP2577032B1 patent drawingFigure 5~7
  • EP2577032B1 patent drawingFigure 8~10

AI summary

The invention relates to an assembly including a reverse thrust device (20) and to a system for actuating said reverse thrust device (20), said device (20) including at least one cowl (30) that is translatably mounted in a direction substantially parallel to a longitudinal axis of a nacelle. Said cowl is capable of passing alternately between a closed position, in which said cowl ensures the aerodynamic continuity of the nacelle, and an open position, in which said cowl opens a passage into the nacelle, said passage being intended for a diverted flow. Said cowl (30) is also extended by at least one variable nozzle section (40). Said nozzle (40) includes at least one rotatably mounted panel (41). Said panel (41) is suitable for pivoting towards at least one position that causes a variation in the nozzle section. The actuation system includes an actuation means (60) that is capable of activating the respective translational and rotational movement of the cowl (30) and the panel (41) of the nozzle (40). Said actuation system is characterized in that it also includes a downstream locking means (80) for the nozzle (40) and the cowl (30). The downstream locking means (80) includes at least two reversible states, one of said states being a locked state in which the downstream locking means (80) is suitable for locking the panel (41) of the nozzle (40) into a position for varying the section for outputting the nozzle with the cowl (30).