Thrust Reverser Actuator Merging for Turbofan Cowl Control
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Solution Overview
Problem
Known thrust reverser assemblies in turbofan engines face operational detriments such as extreme temperatures and mechanical wear, leading to fatigue cracking and potential failure, which results in suboptimal performance and increased maintenance costs due to the use of dedicated actuators and exposed components to adverse environmental conditions.
Innovation Solution
A thrust reverser assembly with a first and second translating cowl positioned relative to a stationary cowl, actuated by an integrated actuator assembly that includes a locking system, reduces stress and exposure by adjusting the discharge area of the fan nozzle duct to enhance operational efficiency and reduce wear, using a positioning assembly to selectively move the cowls between stowed and deployed positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If dedicated actuators are used for each translating cowl, then the thrust reverser assembly can independently control each cowl position, but the cost, weight, and maintenance requirements increase
Solution Approach 1:
The patent combines multiple cowl translation functions into a single integrated actuator system. The actuator assembly includes a motor, planetary gear set, and differential mechanism that can simultaneously or independently translate multiple cowls by distributing rotational motion through gear differentials, eliminating the need for separate dedicated actuators for each cowl while maintaining independent position control capability
Solution Approach 2:
The single actuator assembly is designed to perform multiple functions: it can translate the first cowl, translate the second cowl, and potentially coordinate both movements. The differential gear mechanism allows the same actuator to distribute power differently based on which cowl needs adjustment, making the system universal rather than requiring specialized actuators for each function
2Ease of operation
If flexible hoses and electrical cables are exposed between cowls during operation, then the cowls can move freely between positions, but the components are exposed to adverse environmental conditions causing wear and failure
Solution Approach 1:
The patent employs a flexible bellows assembly that expands and contracts to accommodate cowl movement. This bellows structure encloses and protects flexible hoses and electrical cables running between the stationary and translating cowls, allowing the cowls to move freely while preventing direct exposure of sensitive components to adverse environmental conditions such as moisture, debris, and extreme temperatures
Solution Approach 2:
The bellows assembly acts as an intermediary protective barrier between the moving cowls and the environmental conditions. It mediates the conflict between needing free movement and protecting components by providing a flexible enclosure that moves with the cowls while shielding vulnerable hoses and cables from direct environmental exposure
3Productivity
If the thrust reverser assembly operates under extreme temperatures and mechanical wear, then it can perform its thrust reversal function, but fatigue cracking and failure occur over time
Solution Approach 1:
The patent incorporates protective measures in advance to mitigate the effects of extreme temperatures and mechanical wear. This includes using heat-resistant materials for components exposed to high temperatures, implementing lubrication systems to reduce friction and wear during operation, and designing the actuator mechanism with stress distribution features that prevent fatigue cracking before it occurs
Solution Approach 2:
The thrust reverser assembly utilizes composite materials that combine properties resistant to both extreme temperatures and mechanical wear. For example, ceramic-coated metal components provide thermal resistance while maintaining structural strength, and specialized polymer-composite bearings offer both heat tolerance and reduced friction, allowing the assembly to maintain reliability under harsh operating conditions
Data Source
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AI summary
A thrust reverser assembly (12) for use in a turbofan engine assembly (10) is provided. The engine assembly including a core gas turbine engine (14), a core cowl (18) which circumscribes the core gas turbine engine, a nacelle (32) positioned radially outward from the core cowl to define a fan nozzle duct (38) between the core cowl and a portion of the nacelle, the nacelle including a stationary cowl (58). The thrust reverser assembly includes a first translating cowl (54) slidably coupled to the nacelle, the first translating cowl positionable with respect to the stationary cowl, a second translating cowl (56) slidably coupled to the nacelle such that the first translating cowl is positioned between the stationary cowl and the second translating cowl, the second translating cowl positionable with respect to the first translating cowl, a positioning assembly (120) coupled to the first translating cowl, and an actuator assembly (94) operatively coupled to the second translating cowl for selectively moving the second translating cowl, the actuator assembly configured to engage the positioning assembly to selectively move the first translating cowl.