Actuator Rail Alignment for Thrust Reverser Jamming
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Solution Overview
Problem
Existing thrust reversers for aircraft turbojet engines face issues with jamming and increased mass due to reinforcing structures, which can lead to tilting torques and frictional blockages during the sliding motion of the cowl.
Innovation Solution
A thrust reverser design featuring pulley and cable systems where actuators are aligned with the sliding rails, eliminating tilting moments and jamming risks by exerting forces directly along the axis of the rails, and optionally using thrust reversal flaps to distribute forces circumferentially.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If actuators are mounted on a front frame of the thrust reverser with reinforcement structures, then the thrust reverser can support the forces transmitted by the actuators, but the mass of the nacelle increases
Solution Approach 1:
The thrust reverser hood is divided into two independent half-hoods that can move separately, eliminating the need for a heavy monobloc reinforcement structure. Each half-hood is supported by its own actuator and rail assembly, distributing the structural load and reducing overall mass while maintaining strength.
Solution Approach 2:
The invention transitions from a static reinforcement structure to a dynamic system where the actuator and rail assembly move with the hood. This dynamic configuration eliminates the need for permanent heavy reinforcements, as the structural support is provided only when and where needed during operation.
2Extent of automation
If actuators are grouped in the upper part of the circumference of the thrust reverser, then the thrust reverser can be actuated, but tilting torques cause jamming phenomena in the sliding rails
Solution Approach 1:
The invention uses asymmetric positioning of the actuator relative to the rail assembly, with the actuator mounted on the movable half-hood rather than on a fixed frame. This asymmetric configuration aligns the actuator force vector with the rail's sliding direction, eliminating tilting torques that would otherwise cause jamming.
Solution Approach 2:
Instead of mounting the actuator on a fixed frame and having it push/pull the moving hood, the invention inverts the arrangement by mounting the actuator on the moving hood itself and having it interact with a fixed or semi-fixed rail assembly. This inversion repositions the force application point to eliminate moment arms that cause tilting.
3Device complexity
If a monobloc hood is used for the thrust reverser, then the structure is simplified, but reinforcement structures are needed to support actuator forces which increases mass
Solution Approach 1:
The monobloc hood is segmented into two independent half-hoods, each capable of independent movement. This segmentation eliminates the need for heavy reinforcement structures that would be required to support actuator forces on a rigid monobloc design, while still providing a simplified overall structure that is easier to manufacture and maintain.
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 reduces the risk of jamming and mass, ensuring smooth operation and efficient counter-thrust generation during landing by aligning actuator forces with the sliding motion, thereby enhancing the thrust reverser's functionality and reducing structural weight.
Implementation Method 1
said actuator comprising at least one upstream pulley and one downstream pulley respectively mounted on either side of a corresponding rail or the corresponding slide as appropriate, each pulley being capable of rotating about an axis which may be perpendicular to the longitudinal axis of the reverser
Data Source
Figure 1~3
Figure 4~14b
Figure 7~9
AI summary
The invention relates to a thrust reverser comprising vanes for deflecting flow and a cowl (23) able to move between an open position releasing said deflecting vanes and a closed position covering said deflecting vanes (25) and furthermore comprising rails (45) able to slide in slideways (30), the rails (45) being mounted directly or indirectly on said cowl (23) and the slideways (30) being mounted directly or indirectly on either side of a suspension pylon (8) or vice versa, characterized in that it comprises at least one actuator able to slide the cowl (23) between its open and closed positions, the actuator being disposed in line with the corresponding rail (45), said actuator being: - either an actuator having a rotating nut (51) connected to an endless screw (47), for sliding the corresponding rail or corresponding slideway, as the case may be, - or an actuator suitable for pulling on the corresponding rail or on the corresponding slideway, as the case may be.