Electro-Hydrostatic Circuit Filling with Vacuum-Assisted Air Evacuation
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Solution Overview
Problem
Existing electro-hydrostatic systems (EHA) face challenges in efficiently filling hydraulic circuits without causing cavitation damage to the hydraulic pump, especially in aircraft applications where manual actuation is complex and ineffective.
Innovation Solution
A device comprising a vacuum generator connected to the discharge valve via a shut-off valve to evacuate air, and a pressurized hydraulic fluid source connected to the filling valve via another shut-off valve, allowing for efficient air evacuation and fluid filling without manual actuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual actuation is used to evacuate air from the hydraulic circuit, then air removal is attempted, but the process becomes complex and ineffective with limited air evacuation capability
Solution Approach 1:
The patent replaces the manual mechanical actuation system with a vacuum generator system. The vacuum generator creates negative pressure to automatically evacuate air from the hydraulic circuit, eliminating the need for manual pumping operations while significantly improving air removal effectiveness.
Solution Approach 2:
The patent introduces a vacuum generator as an intermediary device between the hydraulic circuit and the external environment. This intermediary creates a vacuum state that passively draws air out of the circuit through the discharge valve, simplifying the overall process while improving effectiveness.
2Productivity
If the hydraulic circuit is filled without vacuum evacuation, then filling speed is faster, but cavitation damage occurs to the hydraulic pump
Solution Approach 1:
The patent performs vacuum evacuation as a preliminary action before filling the hydraulic circuit. By removing air beforehand, the system prevents cavitation damage during subsequent pump operation while maintaining efficient filling speeds through the vacuum-assisted fluid introduction process.
Solution Approach 2:
The patent converts the potentially harmful effect of air presence (which causes cavitation) into a beneficial vacuum state. The vacuum generator creates negative pressure that not only removes air but also facilitates faster and more controlled fluid filling, turning a harmful factor into a useful tool.
3Reliability
If multiple manual actuations are performed to remove air, then some air is evacuated, but air remains trapped in cavities and the process requires heavy maintenance operations
Solution Approach 1:
The patent implements a self-service filling system where the vacuum generator automatically evacuates air from all circuit cavities simultaneously when activated. The system requires no manual pumping or complex操作步骤, as the vacuum state naturally draws air out through the discharge valve, making maintenance simple and reliable.
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 enables reliable and efficient filling of EHA system circuits, preventing cavitation damage and simplifying maintenance by automating the air evacuation and fluid filling processes.
Implementation Method 1
a vacuum generator (2) designed to be connected to said discharge valve (VP) via a first shut-off valve (V1) in order to eliminate the air or gases present in the circuit
Implementation Method 2
a source for supplying pressurized hydraulic fluid (3), which is designed to be connected to the filling valve (VR) via a second shut-off valve (V2) in order to fill the hydraulic fluid circuit
Data Source
AI summary
A method for filling a hydraulic circuit of an electro-hydrostatic system includes connecting first and third shut-off valves to a discharge valve, and connecting a second shut-off valve to a filling valve, while the second and third shut-off valves are closed, opening the filling valve, the discharge valve and the first shut-off valve and operating a vacuum generator, once a vacuum has been established in the hydraulic circuit, opening the second shut-off valve in order to fill the hydraulic circuit with pressurized hydraulic fluid while the vacuum generator is still in operation, once the hydraulic circuit has been filled with fluid, closing the first shut-off valve and then opening the third shut-off valve in order to bypass the vacuum generator and circulate the fluid through the electro-hydrostatic system until the fluid contained in the hydraulic circuit reaches a predetermined pressure, and closing the discharge valve and the filling valve.