Electric Nose Landing Gear Layout for Low-Fluid Actuation
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Solution Overview
Problem
Conventional hydraulic landing gear systems are inefficient due to the weight of excess hydraulic fluid and labor-intensive leak repairs, and they require continuous pressure for infrequent landing gear actuation, leading to inefficiencies and maintenance challenges.
Innovation Solution
An electric nose landing gear system incorporating electro-hydraulic and electro-mechanical actuators, including electric motors, gear boxes, and hydraulic pumps, which reduce the need for hydraulic fluid and simplify actuation through electric power, allowing for efficient operation and reduced maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If centralized hydraulic systems are used to power the nose landing gear, then the landing gear can be actuated, but the aircraft carries excessive weight due to large volume of hydraulic fluid required to fill long tubing networks
Solution Approach 1:
The patent divides the centralized hydraulic system into distributed electro-hydraulic units located at the nose landing gear assembly. Each unit contains its own hydraulic pump and control valve, eliminating the need for long hydraulic tubing from the aircraft's aft region. This segmentation reduces the total volume of hydraulic fluid required and consequently reduces aircraft weight.
Solution Approach 2:
The patent introduces electro-mechanical actuators as intermediary devices that convert electrical energy directly to mechanical motion for steering and door actuation, eliminating the need for hydraulic fluid in these functions. This intermediary conversion mechanism reduces overall hydraulic fluid requirements while maintaining actuation capability.
2Reliability
If centralized hydraulic systems with long tubing networks are used, then the nose landing gear can be powered, but the system requires continuous hydraulic pressure despite infrequent operation
Solution Approach 1:
The electro-hydraulic actuators are designed to operate periodically only when landing gear actuation is required (before landing and after take-off), rather than maintaining continuous hydraulic pressure. The electric motors drive hydraulic pumps only during these periodic operations, significantly improving energy efficiency by eliminating continuous pressure maintenance.
Solution Approach 2:
The patent replaces the continuous centralized hydraulic pressure system with periodic electro-mechanical actuation. Electric motors directly drive the landing gear actuators when needed, substituting the continuous mechanical hydraulic pressure system with an on-demand electro-mechanical system that is more energy-efficient.
3Reliability
If centralized hydraulic systems are used, then the nose landing gear can be actuated, but leak repairs are labor intensive requiring location, access, and replacement of tubing
Solution Approach 1:
The patent segments the hydraulic system into small, localized electro-hydraulic units at the nose landing gear assembly. This segmentation confines potential leaks to small, accessible areas near the actuators, making leak detection and repair much easier compared to long hydraulic tubing networks that extend throughout the aircraft.
Solution Approach 2:
The distributed electro-hydraulic units are designed to be self-contained and easily replaceable modules. If a leak occurs, the entire actuator unit can be quickly replaced as a self-contained module, eliminating the need for complex leak location and tubing replacement procedures required in centralized hydraulic systems.
4Reliability
If centralized hydraulic systems are used to provide continuous pressure, then the landing gear can be actuated, but the system complexity increases with multiple valves and continuous pressure requirements
Solution Approach 1:
The patent divides the complex centralized hydraulic system with multiple valves into simple, distributed electro-hydraulic units. Each unit contains minimal hydraulic components (pump and control valve) located at the point of use, eliminating the need for complex valve networks and pressure distribution systems required in centralized configurations.
Solution Approach 2:
The patent replaces the complex mechanical hydraulic valve network with straightforward electro-mechanical actuation systems. Electric motors directly control the actuators through simple control circuits, substituting the complex mechanical valve system with an easier-to-manage electro-mechanical control architecture.
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 electric nose landing gear system decreases aircraft weight, enhances efficiency by minimizing hydraulic fluid usage, and simplifies maintenance by reducing the complexity of hydraulic systems and labor-intensive repairs.
Implementation Method 1
the cylinder defines a chamber fluidly coupled to the hydraulic pump, which is configured to provide a hydraulic fluid under pressure to the chamber in order to transition the piston from the first locked position to the second locked position
Implementation Method 2
an electro-hydraulic actuator configured to raise and lower a nose shock strut assembly
Implementation Method 3
a first electro-mechanical actuator configured to steer the nose shock strut assembly; and a second electro-mechanical actuator configured to open and close a fairing door
Data Source
AI summary
A nose landing gear system is disclosed. In various embodiments, the nose landing gear system includes an electro-hydraulic actuator configured to raise and lower a nose shock strut assembly; a first electro-mechanical actuator configured to steer the nose shock strut assembly; and a second electro-mechanical actuator configured to open and close a fairing door.