Aircraft Linear Actuator With Automatic Disengagement at End Stops
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Solution Overview
Problem
Hydraulically controlled linear actuators for aircraft landing gear require numerous hydraulic components, leading to increased mass, leakage issues, and structural modifications, while electrically controlled rotary actuators are complex and incompatible with existing aircraft architectures.
Innovation Solution
An electrically controlled linear actuator with an automatic disengagement/engagement system, featuring a claw ring with deformable claws and elastic return means, allowing mechanical disengagement of the output part from the conversion member at extreme positions to prevent external force transmission, thus avoiding structural modifications and hydraulic fluid leaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If hydraulically controlled linear actuators are used to extend and retract aircraft landing gear, then the actuator can generate sufficient force for heavy loads, but the aircraft requires numerous hydraulic control elements (hoses, pumps, fluid reservoirs, distributors) which increase mass and create leakage risks
Solution Approach 1:
The patent replaces the hydraulic control system with an electrically controlled linear actuator featuring a motor, conversion member, and automatic locking mechanism. This substitution eliminates hoses, pumps, fluid reservoirs, and hydraulic distributors while maintaining the ability to generate sufficient force for landing gear operation through direct electric motor drive.
Solution Approach 2:
The invention extracts and removes the hydraulic control elements (hoses, pumps, fluid reservoirs, distributors) from the system by replacing them with an electrically controlled actuator. This extraction eliminates the associated mass and leakage risks while preserving the core function of extending and retracting the landing gear.
2Device complexity
If electrically controlled rotary actuators are used to extend and retract aircraft landing gear, then the actuator can be simplified compared to hydraulic systems, but the actuator requires a pin generating a large lateral bulk forming a projection that must be secured to the aircraft frame, making it incompatible with existing aircraft architectures
Solution Approach 1:
Instead of using a rotary actuator that requires lateral mounting with a large projection pin, the invention inverts the approach by using a linear actuator that moves parallel to the landing gear axis. This inversion allows the actuator to be mounted within the existing landing gear structure without requiring lateral projections or modifications to the aircraft frame.
Solution Approach 2:
The electrically controlled linear actuator is designed to be universally compatible with existing aircraft landing gear architectures. It can be installed in various configurations (extending beyond, within, or alongside the landing gear) without requiring structural modifications to the aircraft, making it adaptable to different aircraft types and configurations.
3Reliability
If automatic locking means are added to protect the locking mechanism from external forces, then the locking mechanism is protected, but the actuator structure becomes more complex
Solution Approach 1:
The automatic locking mechanism is merged with the conversion member and output part of the actuator. The locking means are integrated into the existing structural components rather than being added as separate external elements. This integration protects the locking mechanism from external forces while minimizing additional structural 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 solution enables a lightweight, leak-free, and easily installable electrically controlled linear actuator that can extend and retract aircraft landing gear without requiring structural modifications to the aircraft, effectively managing external forces and maintaining actuator integrity.
Implementation Method 1
at least one electric motor secured to the frame, the ( s) electric motor(s) comprising a drive shaft rotatable relative to the frame
Implementation Method 2
at least one conversion member for converting a rotational movement of the drive shaft of the motor(s) s) electric(s) in a translational movement of the extendable device in the direction of deployment/retraction
Implementation Method 3
an automatic disengagement/engagement system making it possible to mechanically disengage/engage the output part of the conversion member(s) with the extendable device
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
The present invention relates to an electrically controlled linear actuator (1) and an associated aircraft landing gear. The linear actuator (1) comprises a frame (2), a rod (4), and a cylinder (5) movable in translation relative to each other along a deployment/retraction direction (D1), at least one electric motor (6) fixed to the frame (2), and at least one conversion element (8) for converting the rotational motion of the electric motor (6) into a translational motion. According to the invention, the linear actuator (1) includes an automatic disengagement/engagement system for mechanically disengaging/engaging an output piece (10) of the conversion element (8) with the rod (4) or alternatively with the cylinder (5).