Gearbox Closed Breathing With Bladder Pressure Equalization
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Solution Overview
Problem
Aircraft gearbox transmissions face contamination issues due to air expansion and contraction, which introduces moisture and contaminants, leading to accelerated wear and corrosion, and existing solutions like desiccant breathers require frequent maintenance.
Innovation Solution
A closed breathing system comprising a gearbox, tubing, and a cannister with an impermeable bladder that allows air to expand and contract within the cannister, preventing external contaminants from entering the gearbox.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional breather is used to allow air expansion and contraction, then the gearbox can vent pressure changes, but moisture and contaminants from the atmosphere enter the gearbox causing oil contamination
Solution Approach 1:
The patent introduces a breather fluid (oil) as an intermediary substance between the atmospheric environment and the gearbox internal environment. This fluid allows pressure equalization while blocking contaminants. The breather fluid is circulated through a filter system that removes moisture and contaminants, maintaining a barrier between clean internal atmosphere and contaminated external atmosphere.
Solution Approach 2:
The patent creates an inert or protected atmosphere within the gearbox by using breather fluid to displace atmospheric air that contains moisture and contaminants. The breather fluid environment is maintained as a clean, controlled atmosphere that does not introduce harmful substances to the gearbox components and oil.
2Reliability
If desiccant breathers are used to prevent moisture ingress, then oil contamination is reduced, but frequent maintenance is required
Solution Approach 1:
The patent implements a self-service maintenance system where the breather fluid circulation system automatically filters and removes moisture and contaminants without requiring manual intervention. The system continuously circulates breather fluid through filters that self-regenerate or are easily replaceable, eliminating the need for frequent desiccant replacement and reducing maintenance intervals.
Solution Approach 2:
The patent establishes continuous operation of the breather fluid circulation system that constantly removes moisture and contaminants from the gearbox atmosphere. This continuous protective action maintains oil cleanliness over extended periods without interruption or maintenance, replacing the periodic maintenance requirement of desiccant breathers with ongoing automated protection.
3Reliability
If the gearbox is sealed completely to prevent contaminant ingress, then oil cleanliness is maintained, but pressure changes during temperature and altitude variations cannot be equalized
Solution Approach 1:
The patent uses breather fluid as a mediator that allows pressure transmission between the internal gearbox environment and external atmosphere while blocking contaminant transfer. The fluid transmits pressure changes caused by temperature and altitude variations, equalizing internal and external pressures without allowing atmospheric moisture and contaminants to enter the gearbox.
4Stress or pressure
If a breather system is implemented to manage pressure changes, then pressure equalization is achieved, but atmospheric moisture and contaminants are drawn into the gearbox during cooling and altitude changes
Solution Approach 1:
The patent replaces the atmospheric air environment with a breather fluid environment that is inert to the gearbox components and free from moisture and contaminants. This inert breather fluid atmosphere allows pressure equalization during temperature and altitude changes without introducing harmful substances, as the fluid does not contain the moisture and contaminants present in atmospheric air.
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
This solution effectively prevents moisture and contaminant ingress, extending the life of gearbox components by maintaining a clean environment within the gearbox, reducing maintenance needs.
Implementation Method 1
During aircraft operation, transmissions go through a cycle of being cold, then up to operating temperature, and then back down to cold once the aircraft is no longer running. The air inside the gearbox gets warm and expands
Implementation Method 2
When cooling down, the box pulls air back in from the atmosphere
Data Source
AI summary
Breathing systems and methods for a gearbox is described. Embodiments preferably create a closed system for air within the gearbox. As an operating gearbox warms the air or fluid within, or an altitude change causes air to expand or contract, increased pressure can result and air can escape through tubing to a cannister. The cannister can receive the expanding air in an impermeable cavity that is proximate to a bladder open or partially open to an exterior environment. Air can press on the bladder, expanding the cavity and shrinking the bladder until a pressure equilibrium is reached. As operation of the gearbox is lowered or powered off, or another altitude change occurs, the air can cool and/or retract into the gearbox. The bladder can then expand and press on the cavity until equalizing the pressure within the cannister.