Electric Nose Landing Gear Actuation Without Central Hydraulics
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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 and take-off operations, with a complex network of valves and tubes.
Innovation Solution
An electric nose landing gear system incorporating electro-hydraulic and electro-mechanical actuators, including a locking actuator with a hydraulic pump and piston, reduces weight and complexity by using electric motors and gearboxes to raise, lower, and steer the nose shock strut assembly, and open/close the fairing door, with a method of energizing these actuators to manage the landing gear operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If centralized hydraulic systems are used with long tubing networks, then the landing gear can be actuated, but the aircraft carries excessive hydraulic fluid weight and the system complexity increases
Solution Approach 1:
The patent divides the centralized hydraulic system into distributed electro-hydraulic actuator units located at the nose landing gear. Each actuator contains its own hydraulic pump and control valve, eliminating the need for long hydraulic tubing networks from the aft portion to the nose region. This segmentation reduces the volume of hydraulic fluid required while maintaining reliable landing gear actuation.
2Reliability
If centralized hydraulic systems with long tubing networks are used, then landing gear actuation is achieved, but the system complexity and maintenance requirements increase
Solution Approach 1:
The patent segments the centralized hydraulic system into distributed electro-hydraulic actuator units, each with integrated pumps and control valves. This eliminates the complex network of long hydraulic tubes running from the aft portion to the nose region, significantly reducing system complexity while maintaining actuation reliability.
Solution Approach 2:
Each electro-hydraulic actuator is a self-contained unit with its own hydraulic pump and control valve, enabling independent operation without reliance on the centralized hydraulic system. This self-service capability reduces the overall system complexity and eliminates the need for extensive hydraulic tubing networks.
3Reliability
If centralized hydraulic systems provide continuous pressure, then landing gear actuation is reliable, but energy consumption increases for infrequent operations
Solution Approach 1:
The electro-hydraulic actuators 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 the hydraulic pumps only during these brief operational periods, significantly reducing energy consumption while ensuring reliable actuation when needed.
Solution Approach 2:
The patent replaces the continuous mechanical hydraulic pressure system with an electrically-driven periodic actuation system. Electric motors control the hydraulic pumps to generate pressure only when landing gear operation is required, eliminating the energy waste of maintaining continuous pressure in a centralized hydraulic system.
4Reliability
If conventional hydraulic systems with multiple valves are used, then landing gear actuation is achieved, but the actuation process becomes complex and less efficient
Solution Approach 1:
The patent merges the hydraulic pump, control valve, and actuator into an integrated electro-hydraulic unit. This consolidation eliminates the multiplicity of separate valves required in conventional hydraulic systems, simplifying the actuation process while maintaining reliable landing gear operation.
Solution Approach 2:
Each electro-hydraulic actuator serves as a universal unit that combines the functions of the hydraulic pump, control valve, and actuator mechanism. This multi-functionality eliminates the need for multiple separate valves and components, simplifying the overall actuation system while ensuring reliable landing gear operation.
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 reduces aircraft weight and maintenance complexity, improves efficiency by using electric actuators for landing gear operations, and simplifies the actuation process, reducing energy consumption and labor for repairs.
Implementation Method 1
the cylinder defines a chamber fluidly coupled to a 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
The first electro-mechanical actuator includes a first electric motor and a first gear box
Data Source
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Figure 3A
AI summary
A nose landing gear system (206) is disclosed. In various embodiments, the nose landing gear system includes an electro-hydraulic actuator (244) 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.