Turbojet Thrust Reverser Single Actuator Beam Stop
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Solution Overview
Problem
Thrust reversers for turbojet engines with a single actuator face structural unbalance and high bending moments, leading to difficulties in sliding the movable part relative to the fixed part, especially during emergency operations, and require overdimensioning of the beam for resistance.
Innovation Solution
A thrust reverser design featuring a single actuator with a beam and slider system, where a stop on the beam or slider provides clearance with the engine nacelle pylon, allowing coupling during high-stress events and uncoupling during normal operations to manage stress transmission effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single actuator is used in the thrust reverser, then the assembly is easier and control is simplified, but the structure becomes unbalanced causing high bending moments and difficulties in sliding the movable part
Solution Approach 1:
The patent introduces a stop as an intermediary element between the beam and the pylon. This stop acts as a mediator that provides the necessary structural support and stress distribution path, enabling the single actuator configuration to function reliably without causing excessive bending moments or sliding difficulties.
2Strength
If the beam is overdimensioned to provide resistance to bending, then the structural strength is improved, but the device complexity and weight increase
Solution Approach 1:
The stop serves as an intermediary structural element that shares the load-bearing function. Instead of overdimensioning the beam to resist bending, the stop provides an additional support path that distributes stresses, allowing the beam to be dimensioned appropriately without excessive complexity or weight.
Solution Approach 2:
The stress transmission path is segmented into multiple pathways: through the beam-slider mechanism and through the stop-ponylon contact. This segmentation allows each component to be optimized independently, avoiding the need to overdimension the beam while maintaining overall structural strength.
3Reliability
If a tight fit is obtained between fixed and movable parts to ensure sealing, then the seal is improved, but unwanted stresses are transmitted from the engine to the pylon
Solution Approach 1:
The stop acts as an intermediary element that decouples the stress transmission path. It provides a controlled contact point with the pylon that allows the movable part to be sealed against the fixed part while preventing unwanted stresses from being transmitted through the beam to the pylon structure.
Data Source
AI summary
This summary relates to a thrust reverser for a turbojet engine mounted on an engine nacelle pylon, comprising a fixed part, a movable part, coaxial and mounted in translation with respect to the fixed part and sealingly inserted against the fixed part by blocking an air outlet passage in a closed state whereas the air outlet passage is freed up in the extended state, and a single actuating device including a beam, a slider, and a driving device, configured to drive the movable part in translation with respect to the fixed part, wherein the beam comprises a stop taking the form of a protuberance protruding on a radially outer surface of the beam and configured to have a clearance with respect to said engine nacelle pylon.