Aircraft Gearbox Lubrication Layout With Cross-Loop Fault Isolation
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Solution Overview
Problem
Rotary aircraft gearbox lubrication systems face failures due to lubricant loss, leading to potential loss of momentum and lift, necessitating a reliable lubrication distribution and fault isolation mechanism to prevent unplanned landings.
Innovation Solution
A lubrication system comprising multiple gearboxes and lubricant coolers connected by fluid passages, with a fault isolating hydraulic control system and electronic controller that adjusts flow paths and rates to maintain lubrication in case of component failures, allowing continued flight operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single lubrication system is used for multiple gearboxes, then the system structure is simple, but lubricant loss leads to gearbox failure and loss of lift
Solution Approach 1:
The lubrication system is divided into multiple independent loops, with each loop containing a dedicated lubricant cooler and fluid passages that can operate independently. This segmentation allows one loop to fail without affecting the others, maintaining reliability while keeping individual loop structures simple
Solution Approach 2:
The system incorporates dynamic flow control capabilities through the fault isolating hydraulic control system that can adjust flow paths and rates based on operational conditions and detected faults, optimizing lubrication delivery adaptively
2Temperature
If lubricant coolers are positioned internal to gearboxes, then cooling is direct and efficient, but maintenance and fault isolation become difficult
Solution Approach 1:
The lubricant coolers are extracted from the internal gearbox cavity and positioned externally, allowing them to be accessed, maintained, and replaced without disassembling the gearbox. The fluid passages connect the external coolers to the gearboxes, maintaining cooling functionality while improving accessibility
Solution Approach 2:
Fluid passages serve as intermediaries that transmit lubricant between the externally positioned coolers and the internal gearbox components, enabling efficient cooling transmission over distance while maintaining physical separation for ease of maintenance
3Reliability
If fault isolation mechanisms are added to the lubrication system, then reliability improves, but system complexity increases
Solution Approach 1:
The fault isolating hydraulic control system merges sensing, control, and actuation functions into an integrated system that automatically detects faults and isolates affected loops, providing reliable fault isolation without requiring complex manual intervention systems
Solution Approach 2:
The system incorporates automatic fault detection and isolation capabilities where the hydraulic control system self-regulates by detecting faults through sensors and automatically adjusting flow paths to isolate problems without external intervention, maintaining reliability while managing complexity
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 system ensures continued operation of rotary wing aircraft by effectively distributing lubricant and isolating faults, preventing lubricant loss and maintaining gearbox functionality, thus avoiding unplanned landings.
Implementation Method 1
a first lubricant cooler positioned external the first and second internal cavities, the first lubricant cooler configured to hold lubricant, a second lubricant cooler positioned external the first and second internal cavities, the second lubricant cooler configured to hold lubricant
Implementation Method 2
a plurality of fluid passages fluidly connecting the first lubricant cooler and second lubricant coolers to each of the first gearbox and the second gearbox
Data Source
AI summary
A lubricant system includes a first gearbox defining a first internal cavity, a second gearbox defining a second internal cavity, a first lubricant cooler positioned external the first and second internal cavities, a second lubricant cooler positioned external the first and second internal cavities, and a plurality of fluid passages fluidly connecting the first lubricant cooler and second lubricant coolers to each of the first gearbox and the second gearbox. The first lubricant cooler and the second lubricant cooler are configured to hold lubricant. The fluid passages include a first main fluid passage fluidly connecting the first lubricant cooler to the first gearbox, a second main fluid passage fluidly connecting the second lubricant cooler to the second gearbox, a first auxiliary passage fluidly connecting the first lubricant cooler to the second gearbox, and a second auxiliary passage fluidly connecting the second lubricant cooler to the first gearbox.