Aircraft Landing Gear Actuator Breather for Moisture and Pressure Control
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Solution Overview
Problem
Electromechanical actuator systems in aircraft landing gear face condensation issues during flight cycles, leading to corrosion, short circuits, and premature seal failure due to pressure differences created by hermetic sealing attempts to mitigate condensation.
Innovation Solution
A breather apparatus comprising a housing with a moisture pump, a protective cap, a moisture trap, and a desiccant cartridge that balances internal and external pressures and temperatures, while preventing water ingress through a porous membrane and O-ring sealing, and a diffusion inhibition tube to manage humidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the actuator mechanism is hermetically sealed within the housing to prevent condensation, then the reliability of the actuator mechanism is improved, but a substantial pressure difference is created between internal and external pressure, causing premature seal failure
Solution Approach 1:
The housing is divided into separate functional zones: a hermetically sealed actuator mechanism compartment and a separate vented housing compartment. This segmentation allows the actuator to be sealed against condensation while the housing can vent pressure differences, preventing seal failure on the actuator while maintaining pressure balance in the housing.
Solution Approach 2:
A desiccant cartridge is introduced as an intermediary substance within the sealed housing compartment. The desiccant absorbs moisture from the air, maintaining aridity and preventing condensation on the actuator mechanism, thereby enabling hermetic sealing without causing corrosion or hydrolysis.
2Stress or pressure
If an opening is provided in the housing to balance pressure and temperature, then the pressure difference between internal and external environment is reduced, but condensation can enter the actuator mechanism causing corrosion and hydrolysis
Solution Approach 1:
Different parts of the housing have different sealing characteristics: the actuator mechanism compartment is hermetically sealed with high sealing quality to prevent condensation, while the housing allows pressure equalization through controlled venting. This local differentiation of sealing properties enables simultaneous pressure balancing and condensation prevention.
Solution Approach 2:
A porous membrane is used in the breather apparatus to allow selective passage of air while blocking liquid water. The porous structure permits pressure equalization through gas diffusion while the O-ring sealing and membrane configuration prevent liquid condensation from penetrating into the actuator mechanism.
3Reliability
If desiccants are used to reduce condensation accumulation, then the aridity within the housing is maintained, but the pressure difference between internal and external environment increases, straining the seals
Solution Approach 1:
The housing is segmented into a sealed actuator compartment containing desiccants and a separate vented housing compartment. This allows the desiccants to maintain aridity in the actuator compartment while the housing compartment vents to external pressure, eliminating the pressure difference strain on seals.
Solution Approach 2:
The desiccant cartridge acts as an intermediary moisture-absorbing element that maintains low humidity levels within the sealed actuator compartment. By removing moisture from the air, the desiccant prevents condensation while the separate venting system manages pressure differences, allowing both functions to coexist without compromising seals.
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
Maintains aridity within the housing, reducing pressure differences and extending seal life, thereby enhancing the reliability and longevity of the actuator mechanism by preventing corrosion and moisture-related failures.
Implementation Method 1
preventing water ingress through a porous membrane
Implementation Method 2
use desiccants to facilitate reducing an amount of condensation that can accumulate
Implementation Method 3
O-ring sealing
Data Source
AI summary
An actuator system and a method for assembling the same are provided. An actuator system includes a housing and a cap. The housing includes a cavity defined by the housing and an opening defined in a wall of the housing. The housing encases an actuator within the cavity. The cap is coupled to the housing to facilitate shielding the opening from a surrounding environment.