Aviation Gas Turbine Thrust Reverser Two-Stage Drive Mechanism
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Solution Overview
Problem
Existing aircraft gas turbine thrust reversal devices suffer from reduced efficiency due to disruptive lever mechanisms and complex structures, which impede airflow and increase manufacturing costs, while also complicating maintenance access.
Innovation Solution
A two-stage drive element is used to axially displace the rear engine cowling, positioning deflection elements and blockage doors entirely within the cowling in forward thrust mode, allowing for a smooth flow surface and efficient thrust reversal by pivoting these elements into the bypass duct during reverse thrust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a lever mechanism is used to position blockage doors and deflection elements, then thrust reversal function is achieved, but airflow efficiency is reduced and manufacturing complexity increases
Solution Approach 1:
The patent removes the lever mechanism and its bearings from the bypass duct, extracting the source of flow disruption. The blockage doors and deflection elements are repositioned to be driven directly by the sliding cowling without intermediate mechanical linkages, eliminating components that disturb airflow and reduce manufacturing complexity
Solution Approach 2:
The patent combines the functions of the cowling slide mechanism with the drive mechanism for the blockage doors and deflection elements. The single sliding motion of the cowling simultaneously positions all thrust reversal components, merging multiple functions into one simple mechanical action that reduces overall device complexity
2Ease of operation
If a lever mechanism with bearings is installed in the bypass duct, then blockage doors can be positioned, but airflow efficiency is minimized
Solution Approach 1:
The patent extracts the lever mechanism and bearings from the bypass duct flow path. Instead, the blockage doors are positioned through direct coupling with the sliding cowling, eliminating mechanical components that create flow disturbances and energy losses while maintaining the positioning function
Solution Approach 2:
The patent replaces the complex lever mechanism with a simpler direct mechanical coupling system. The sliding cowling directly drives the blockage doors and deflection elements through integrated mounting, substituting a multi-component mechanical system with a streamlined configuration that preserves functionality while reducing flow interference
3Power
If the rear area of the engine cowling is slid aft to create annular free space, then reverse thrust is achieved, but access to the core engine becomes more difficult
Solution Approach 1:
The patent segments the engine cowling into a fixed front area and a movable rear area. The rear area slides axially to create annular free space for reverse thrust, while the segmented design allows independent movement that can be controlled to provide maintenance access when needed
Solution Approach 2:
The patent implements a dynamic cowling configuration where the rear area can slide axially between forward and aft positions. This dynamic capability allows the system to provide reverse thrust when slid aft, and potentially maintain partial access configurations, making the system adaptable to different operational and maintenance requirements
4Reliability
If deflection elements are arranged on the peripheral area, then thrust reversal is achieved, but manufacturing complexity and costs increase
Solution Approach 1:
The patent designs the movable rear cowling area to serve multiple functions: it acts as the drive mechanism for positioning blockage doors, provides the structural framework for mounting deflection elements, and creates the annular free space for reverse thrust flow. This multi-functionality reduces the number of separate components needed, simplifying manufacturing and reducing costs
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 enhances airflow efficiency, reduces manufacturing complexity, and lowers costs by minimizing components that disrupt flow, while enabling precise control of thrust reversal with a smooth transition between thrust modes.
Implementation Method 1
a rear area (30) of the engine cowling (28) can be displaced in the axial direction of the engine from a closed forward position into a reverse thrust position, which results in the annular free space (31)
Implementation Method 2
through which the reverse thrust flow can be discharged radially outward and counter to the direction of flight
Implementation Method 3
The blockage doors are pivoted into their full blockage position, in which they divert the air flow to reverse the thrust
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The gas turbine thrust reverser has a cowl (28) whose rear portion (30) is more displaced in the axial direction of an engine. An annular free space arises in a front portion (29) of the cowl. The turning elements and blockage elements are coupled to rear portion of the cowl. A drive element is arranged between the front portion and the rear portion to cause axial displacement of the rear portion. A drive element is formed in two stages for partial and full axial displacements of rear portion of cowl.