Telescoping Landing Gear Strut With Pre-Pressurized Chamber
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Solution Overview
Problem
Existing retraction/extension actuation systems for aircraft landing gears face challenges in ensuring reliable hydraulic power and fluid volume availability, while also needing to be simple, lightweight, and compact, with increased complexity, weight, and cost in rotorcrafts due to emergency extension requirements.
Innovation Solution
A telescoping strut with a central pre-pressurized extension chamber, a surrounding retraction chamber, and a damping chamber, optimized for efficient hydraulic fluid circulation and emergency extension capabilities, featuring a compact and integrated design with pre-loaded pressures and a pneumatic spring system for enhanced energetic efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an emergency hydraulic tank and additional actuator are installed for emergency extension, then emergency extension capability is improved, but device complexity, weight, costs and volume increase
Solution Approach 1:
The patent combines the emergency extension function with the normal retraction/extension hydraulic system by using a common hydraulic tank that can serve both normal operation and emergency extension. The hydraulic circuit is designed so that the same fluid source and pressure system can be used for both routine landing gear operations and emergency extension, eliminating the need for separate emergency hydraulic components.
Solution Approach 2:
The hydraulic tank and associated components are designed to perform multiple functions: normal retraction, normal extension, and emergency extension. The system uses a universal hydraulic approach where the same fluid reservoir and pressure generation mechanisms serve all extension requirements, making the emergency system not a separate addition but an integrated capability of the existing hydraulic architecture.
2Reliability
If an emergency hydraulic tank and additional actuator are installed for emergency extension, then emergency extension capability is improved, but weight increases
Solution Approach 1:
The patent combines the emergency extension function with the normal retraction/extension hydraulic system by using a common hydraulic tank that can serve both normal operation and emergency extension. The hydraulic circuit is designed so that the same fluid source and pressure system can be used for both routine landing gear operations and emergency extension, eliminating the need for separate emergency hydraulic components.
Solution Approach 2:
The hydraulic tank and associated components are designed to perform multiple functions: normal retraction, normal extension, and emergency extension. The system uses a universal hydraulic approach where the same fluid reservoir and pressure generation mechanisms serve all extension requirements, making the emergency system not a separate addition but an integrated capability of the existing hydraulic architecture.
3Adaptability or versatility
If distinct components are used for retraction and damping functions, then component arrangement flexibility is improved, but overall configuration becomes too heavy and complex
Solution Approach 1:
The patent merges the retraction actuator and damping functions into a single integrated strut assembly. The telescopic strut contains both the retraction/extension mechanism and the damping chamber within the same structural element, eliminating the need for separate damping components and reducing overall system complexity while maintaining the ability to perform both functions effectively.
Solution Approach 2:
The telescopic strut is designed as a multi-functional component that simultaneously provides retraction/extension actuation and damping capabilities. The single strut structure incorporates hydraulic chambers for both functions, making it a universal element that replaces what would traditionally require multiple separate components.
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 telescoping strut provides a compact, efficient, and reliable solution for retraction, extension, and damping functions, optimizing fluid power ratio and stroke sensitivity, while enabling power-free emergency extension, thus enhancing the energetic efficiency and reducing weight and complexity in aircraft landing gear systems.
Implementation Method 1
A telescoping strut with a central pre-pressurized extension chamber, a surrounding retraction chamber, and a damping chamber, optimized for efficient hydraulic fluid circulation and emergency extension capabilities, featuring a compact and integrated design with pre-loaded pressures and a pneumatic spring system for enhanced energetic efficiency.
Implementation Method 2
The telescoping strut has only one fluid input/output passage for fluid circulation from an hydraulic source in an hydraulic generation architecture of the aircraft to the surrounding retraction chamber for opposing an extension positive pressure in the central extension chamber
Implementation Method 3
A telescoping strut with a central pre-pressurized extension chamber, a surrounding retraction chamber, and a damping chamber
Data Source
AI summary
A telescoping strut for a retractable landing gear in an aircraft. The telescoping strut comprises a pre-pressurized and central extension chamber extending along the telescoping strut and a surrounding retraction chamber. For retraction, an hydraulic generation architecture of the aircraft feeds a single input/output passage of the surrounding retraction chamber with a overcoming fluid pressure that overwhelms a extension positive pressure in the central extension chamber and opposes the effect of the pre-pressurizing. The retraction system is for instance for a rotorcraft.