Thrust Reverser Passive Coupler Damping
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Solution Overview
Problem
Existing thrust reverser systems for aircraft turbojet engines with variable-section nozzles are complex, prone to reliability issues due to the high number of parts and lack of damping in coupling and uncoupling processes, leading to wear and mechanical stress.
Innovation Solution
A thrust reverser system featuring a passive coupler with a hollow casing, a piston, and a unidirectional flow limiter that allows fluid communication between compartments, eliminating the need for synchronization and alignment of the thrust reverser cowl and nozzle, and using fluid flow to control the movement of the actuating rod and nozzle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a coupling device is used to connect the movable cowl and variable nozzle, then the nozzle and cowl can be moved simultaneously, but the device becomes complex and requires alignment of different parts
Solution Approach 1:
The patent merges the coupling device functions into the actuator itself. The actuator body serves as the coupling mechanism, with the piston rod directly connecting to the movable cowl assembly. This integration eliminates separate coupling components and their associated alignment requirements, while still achieving simultaneous movement of the nozzle and cowl through the shared actuator mechanism.
Solution Approach 2:
The actuator is designed to perform multiple functions: it acts as both the driving mechanism for nozzle section variation and as the coupling device for coordinating cowl and nozzle movement. The actuator body provides both actuation force and mechanical coupling, eliminating the need for dedicated coupling components and reducing overall system complexity.
2Ease of operation
If a coupling device with high number of parts is used, then the nozzle and cowl can be coupled, but reliability decreases due to more parts and potential failure points
Solution Approach 1:
By integrating the coupling function into the actuator body, the patent reduces the number of discrete parts. The actuator serves as both the actuation mechanism and the coupling device, eliminating multiple separate components that would each be potential failure points. This integration directly improves reliability by reducing the component count and failure surfaces.
3Speed
If coupling and uncoupling jolts are not damped, then the mechanism responds quickly, but wear and reliability of mechanical parts deteriorate
Solution Approach 1:
The patent incorporates damping elements within the actuator mechanism that are pre-positioned to absorb coupling and uncoupling jolts. These damping features are built into the actuator structure itself, providing shock absorption before the mechanical impacts can cause wear to other components. This beforehand cushioning protects the mechanical parts while maintaining quick response capability.
4Manufacturing precision
If alignment of different parts is required for coupling, then precise connection can be achieved, but the device becomes more complex and time-consuming to operate
Solution Approach 1:
The patent eliminates the need for separate alignment procedures by integrating the coupling function into the actuator's normal operation. The actuator body and piston rod are designed with built-in alignment features that automatically align during the actuation process, eliminating the need for manual or complex automated alignment procedures before coupling.
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
The system is simpler, lighter, more compact, and more reliable, with reduced wear and increased reliability by eliminating the need for complex alignment and synchronization, and utilizing fluid flow to control nozzle section changes.
Implementation Method 1
a unidirectional flow limiter ensuring the fluid connection between the two compartments, said flow limiter limiting the flow rate of the fluid in the direction of a fluid flow going from the downstream compartment to the upstream compartment, and allowing free circulation of the fluid in the direction of a fluid flow going from the upstream compartment to the downstream compartment
Implementation Method 2
a piston fixed to the actuating rod of the actuator and which is slidably mounted in the casing of the coupler, hermetically dividing said cavity into two compartments comprising an upstream compartment located between the upstream wall and the piston and a downstream compartment located between the downstream wall and the piston
Data Source
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AI summary
The invention concerns a thrust reverser (18) for an aircraft turbojet engine nacelle (10) comprising at least one movable thrust reverser cowling (20), a means for locking the cowling (20), an outlet nozzle (22) having a variable cross-section that is arranged in the downstream extension of said cowling (20) and that is movable, and at least one actuator (24) that comprises an actuating rod (28) capable of moving the variable nozzle (22) and the movable cowling (20), remarkable in that the reverser (18) is provided with a passive coupler (30) comprising a housing (32) that is rigidly connected to the thrust reverser cowling (20), a piston (42) attached to the actuating rod (28) of the actuator (24) and that is slidingly mounted in the housing (32) of the coupler (30), sealingly dividing a cavity (34) into two compartments (44, 46) filled with fluid, and a unidirectional flow limiter (50) providing the fluidic connection between the two compartments (44, 46) of the housing (42), said flow limiter (50) limiting the circulation rate of the fluid in the direction of a fluid flow from a downstream compartment (46) to an upstream compartment (44), and allowing the free circulation of the fluid in the direction of a fluid flow from the upstream compartment (44) to the downstream compartment (46).