Turbojet Thrust Reverser Seal Fixing System
Solution Overview
Problem
The existing fixing systems in aircraft turbojet engines require significant effort to close due to the need for robust seals that withstand manufacturing and assembly tolerances and in-flight movements, leading to increased forces and potential sealing issues.
Innovation Solution
A fixing system with a crushing mechanism that directs forces in the longitudinal direction, reducing the diameter of the seal and the forces required for closure, by using a flange that moves mainly in the longitudinal direction and incorporating elastic or rigid strips to facilitate the closing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a robust seal is used to withstand manufacturing and assembly tolerances and in-flight movements, then the sealing reliability is improved, but the forces required to close the covers are significantly increased
Solution Approach 1:
The seal is designed to be movable rather than fixed, allowing it to adapt to manufacturing tolerances and in-flight movements. The seal can move in the transverse direction to accommodate these variations while maintaining sealing effectiveness, thereby reducing the forces required for closure.
Solution Approach 2:
The seal's position and orientation parameters are allowed to vary within certain limits. By permitting the seal to move in the transverse direction and adjust its position, the system can accommodate tolerance variations without requiring excessive closing forces, while still maintaining reliable sealing.
2Reliability
If the seal diameter is increased to ensure robustness and withstand transverse movements, then the sealing performance is improved, but the device complexity and size are increased
Solution Approach 1:
Instead of using a larger static seal, the invention employs a smaller seal that is allowed to move dynamically. The seal's mobility enables it to compensate for transverse movements and tolerance variations, achieving reliable sealing with a smaller diameter and reduced complexity.
Solution Approach 2:
The seal's functionality is enhanced by allowing movement in the transverse dimension rather than increasing the seal diameter in the radial dimension. This dimensional approach to tolerance compensation achieves sealing reliability without increasing seal size or complexity.
3Device complexity
If the seal is fixed in position to maintain simplicity, then the device complexity is reduced, but the ability to accommodate manufacturing tolerances and in-flight movements is compromised
Solution Approach 1:
The seal is designed with movable mounting that allows it to adjust its position in the transverse direction. This dynamic capability enables the seal to accommodate manufacturing tolerances and in-flight movements while maintaining sealing effectiveness, without significantly increasing device complexity.
Solution Approach 2:
The seal's position parameters are made variable rather than fixed. This allows the seal to adapt to tolerance variations and movement conditions, maintaining reliable sealing while keeping the overall device complexity manageable through controlled parameter variation.
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 solution reduces the effort needed to close the covers and maintains the seal's integrity by minimizing transverse movements, thus enhancing the sealing efficiency and reducing the size of the seal, while maintaining fluid and fire tightness.
Implementation Method 1
a crushing means attached to the second hood and arranged to crush the bead towards the fixing wall when the second hood moves from the open position to the closed position
Implementation Method 2
incorporating elastic or rigid strips to facilitate the closing process
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
The invention relates to a turbojet engine with two thrust reverser modules, each comprising an outer casing, an inner casing, and a fastening system (400) for the inner casing to the outer casing, and comprising first and second cowlings (302, 304), where a housing (316) between the cowlings (302, 304) has a fastening wall (402), a seal (406) with a flange (411) fixed to the fastening wall (402), and a crushing means (450) integral with the second cowling (304) and arranged to crush the flange (411) towards the fastening wall (402) when the second cowling (304) moves from the extended to the retracted position. Consequently, the flange moves in the longitudinal direction, thus limiting shear stresses in the seal and transverse displacements due to manufacturing and assembly tolerances and in-flight movement.