Shock Absorber Maintenance Apparatus for Automated Gas-Liquid Exchange
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for maintaining aircraft shock absorbers filled with both gas and liquid are laborious, inaccurate, and difficult to automate, requiring jacking up the aircraft and using high-pressure liquid pumps, and are not suitable for shock absorbers with free pistons that separate gas and liquid chambers.
Innovation Solution
A maintenance apparatus and method that uses a liquid reservoir, gas reservoir, and coupling member to create a pressure difference, allowing for automated exchange of liquid and gas within the shock absorber without jacking, using control means and sensing systems to bring the partial volumes of gas and liquid to predetermined target levels, even when the shock absorber is loaded.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the aircraft is jacked up to relieve the shock absorber of its load, then the shock absorber can be maintained, but the process becomes time-consuming and introduces risks
Solution Approach 1:
The shock absorber maintains itself under load through the automated exchange mechanism. The coupling member and reservoir system enable the shock absorber to exchange liquid and gas phases while remaining in its loaded state, eliminating the need for external jacking operations and allowing self-maintenance during normal operational conditions
Solution Approach 2:
The system prepares for maintenance by establishing the coupling member connection between the shock absorber and reservoirs beforehand. The control means and sensing systems are pre-configured to detect phase boundaries and automatically initiate the exchange process, eliminating the need for preliminary aircraft jacking and manual preparation steps
2Manufacturing precision
If a high-pressure liquid pump is used to supply liquid to the shock absorber, then the liquid level can be corrected, but the device becomes expensive and complex
Solution Approach 1:
The system uses pneumatic pressure from the gas reservoir to drive liquid exchange instead of mechanical pumps. The gas phase pressurizes the liquid in the coupling member, forcing it into or out of the shock absorber based on detected needs, achieving precise liquid level control through gas pressure regulation rather than complex hydraulic pumping systems
Solution Approach 2:
The coupling member acts as an intermediary between the shock absorber and the reservoirs. It contains the exchangeable liquid and gas phases and transfers them to/from the shock absorber under controlled pressure, eliminating the need for direct high-pressure pump connections and reducing overall system complexity
3Ease of operation
If the shock absorber is maintained while loaded, then the maintenance process is simplified, but the pressure difference between liquid and gas must be maintained
Solution Approach 1:
The sensing system continuously monitors the positions of the free piston and liquid level within the shock absorber. This feedback information is processed by the control means, which automatically adjusts the gas pressure in the coupling member to maintain the correct pressure differential, enabling loaded maintenance while automatically managing pressure control requirements
Solution Approach 2:
The system dynamically changes the pressure parameter of the gas in the coupling member based on real-time detection of shock absorber internal conditions. By adjusting gas pressure rather than maintaining fixed pressure, the system adapts to loaded conditions and automatically maintains the necessary pressure difference for proper phase exchange
4Reliability
If a free piston separates the gas and liquid chambers, then the shock absorber functions better, but it becomes impossible to determine if liquid has entered the gas chamber
Solution Approach 1:
The system replaces mechanical inspection methods with sensing systems that detect the positions of the free piston and liquid level. These sensing systems provide electrical or optical signals to the control means, enabling automatic detection of phase boundaries and liquid intrusion without requiring physical access or disassembly of the shock absorber
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
Enables efficient, automated, and universally applicable maintenance of shock absorbers, reducing the risk of errors and cycle time, and allowing maintenance under varying loads, including those from weather and ship movements, while protecting free pistons from overloading.
Implementation Method 1
the coupling member causes a pressure difference between the pressure in the liquid reservoir and the pressure in the gas reservoir
Implementation Method 2
the pressure of the gas in the gas reservoir provides a spring action to the pressurized liquid in the liquid reservoir via the coupling member
Implementation Method 3
the gas and the liquid are pressurized during operation, due to the load on the shock absorber
Data Source
AI summary
The present invention relates to a maintenance apparatus for a shock absorber of a landing gear, comprising a liquid reservoir which can be connected to an interior space of the shock absorber via a liquid line, a gas reservoir which can be connected to the interior space via a gas line, a coupling member for sealingly coupling the liquid reservoir and the gas reservoir, wherein the maintenance apparatus is configured to allow an exchange to occur of liquid and gas between the liquid reservoir and gas reservoir, respectively, and the interior space, the maintenance apparatus comprising control means for determining that a partial volume of the interior space occupied by the gas reaches a reference level as a result of the exchange and for bringing the partial volume of the interior space of the shock absorber respectively occupied by the gas and the liquid to a target level. The invention also relates to a maintenance method.