Self-locking Plug Sealing Device for Aircraft Engines
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Solution Overview
Problem
Existing plug-type sealing devices in aircraft engines face issues with untimely unscrewing due to vibrations, require complex installation processes, and can damage the engine case during tightening, especially when exposed to severe operating conditions over long periods.
Innovation Solution
A sealing device with a central body and a rigid skirt featuring locking and unlocking means, including a first releasable coupling component coupled with the central body via guide means and a second coupling component secured against rotation, which transmits tightening thrust to the case without causing damage, utilizing a compact design and resilient return means for reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If locking means are added to prevent untimely unscrewing, then reliability is improved, but device complexity increases
Solution Approach 1:
The locking system automatically engages and disengages based on the screwing motion itself, without requiring external actuators or complex control mechanisms. The teeth on the rings mesh automatically during axial movement, and the spring provides automatic resetting, making the system self-regulating and simplifying the overall device complexity.
Solution Approach 2:
The locking mechanism transitions from a static locked state to a dynamic unlocked state through the screwing motion. The rings rotate relative to each other, allowing the teeth to engage and disengage dynamically. This dynamic behavior enables automatic locking without adding permanent complex structures to the plug.
2Reliability
If a ring is press-fitted onto the case for locking, then reliability is improved, but ease of manufacture deteriorates
Solution Approach 1:
The locking function is segmented into two parts: the first ring is integrated with the plug, and the second ring is integrated with the case. This segmentation allows each ring to be manufactured and installed independently, eliminating the need for complex press-fitting operations on the case while maintaining reliable locking through the meshing teeth.
Solution Approach 2:
The locking function is merged with the existing plug structure by integrating the first ring directly into the plug body. This eliminates the need for separate locking components and complex installation procedures, as the locking mechanism becomes an inherent part of the plug assembly process.
3Productivity
If the plug head transmits tightening thrust to the case, then productivity is improved, but object-affected harmful factors increase
Solution Approach 1:
The second ring acts as an intermediary between the plug head and the case. It receives the tightening thrust from the plug and distributes it to the case through its own structure, preventing direct concentrated contact that could damage the delicate engine case alloy. This intermediary protects the case while maintaining effective force transmission.
4Ease of operation
If sliding arrangements are used for locking, then ease of operation is improved, but reliability deteriorates
Solution Approach 1:
The sliding arrangement is replaced with a meshing teeth system that engages through axial movement rather than continuous sliding. The teeth on the rings interlock during the screwing motion, providing positive mechanical engagement that is more reliable for long-term vibration resistance compared to sliding contacts that can become frictional and wear over time.
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 solution effectively prevents untimely unscrewing, simplifies installation, and maintains the engine case's integrity by reducing frictional contact and requiring minimal additional machining, ensuring reliable performance over extended periods.
Implementation Method 1
resilient return means for reliable operation
Data Source
AI summary
A sealing device in the form of a plug that is receivable in a threaded hole of a case includes a threaded central body, a skirt connected to the central body, and locking/unlocking means that opposes spontaneous unscrewing of the plug and is automatically activated by rotation of the plug and corresponding movement along an axis. The locking/unlocking means includes a first releasable coupling component coupled for rotation with the central body, and a second releasable coupling component facing the first coupling component at least during screwing and unscrewing. In at least in a tightened condition of the plug, the second coupling component is secured against rotation relative to the case by rotation restricting means located inside the threaded bore. In the screwed condition, an annular end face of the skirt bears against a bearing face of the second releasable coupling component to transmit tightening thrust to the case.