Aircraft Landing Gear Linear Motor Actuation
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Solution Overview
Problem
Conventional aircraft landing gears with hydraulic cylinders impose a significant burden on the aircraft's hydraulic system in terms of weight, capacity, and energy consumption, and electric actuators using rotary motors and gear mechanisms are prone to failures and complications, leading to unreliability and increased weight.
Innovation Solution
A landing gear system utilizing a linear motor as a replacement for hydraulic cylinders, which extends and retracts along an axis, eliminating the need for conversion mechanisms and separate safety components, and includes a controller for precise control and energy-efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydraulic cylinder is used to raise and lower the landing gear structure, then the landing gear can be deployed and retracted, but the hydraulic system becomes burdened with significant weight, capacity, and energy consumption
Solution Approach 1:
The patent replaces the hydraulic cylinder (mechanical-hydraulic system) with a linear motor (electromagnetic system). The linear motor directly generates linear motion through electromagnetic force, eliminating the need for hydraulic fluid, pumps, and associated mechanical components, thereby significantly reducing system weight while maintaining reliable landing gear deployment
Solution Approach 2:
The patent extracts and removes the hydraulic system components (hydraulic cylinder, hydraulic fluid, pumps) from the landing gear actuation system. By taking out these heavy components and replacing them with a compact linear motor, the system achieves weight reduction while preserving the essential function of landing gear deployment
2Weight of moving object
If a rotary electric motor and gear mechanism are used to replace the hydraulic cylinder, then the landing gear can be actuated electrically, but the structure becomes complicated and reliability decreases due to potential failures in the gear mechanism
Solution Approach 1:
The patent replaces the rotary electric motor with a gear mechanism (mechanical system) with a linear motor (electromagnetic system). The linear motor directly produces linear motion through electromagnetic force without requiring mechanical conversion, eliminating gear jamming, tooth wear, and other mechanical failure modes, thereby significantly improving actuator reliability
Solution Approach 2:
The patent eliminates the intermediary gear mechanism that converts rotary motion to linear motion. The linear motor acts as a direct intermediary between electrical energy and linear mechanical motion, removing the intermediate conversion step that introduces potential failure points and structural complexity
3Reliability
If safety measures such as a clutch are added to disconnect the landing gear structure from the electric actuator, then the landing gear can be protected from damage, but the structure becomes more complicated and weight increases
Solution Approach 1:
The patent replaces the mechanical clutch safety mechanism with the inherent electromagnetic characteristics of the linear motor. The linear motor can be electronically controlled to prevent overload conditions and can be rapidly deactivated through software control, providing safety without mechanical disconnect components, thereby reducing structural complexity
Solution Approach 2:
The patent implements electronic feedback control through the controller that monitors the linear motor's operation. The controller can detect abnormal conditions (such as excessive current indicating jamming) and automatically adjust or stop motor operation, providing active safety management without mechanical safety components like clutches
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 linear motor-based landing gear reduces weight, ensures reliability, and simplifies the structure by eliminating hydraulic cylinders and gear mechanisms, while providing safe and energy-efficient operation with built-in safety measures.
Implementation Method 1
a linear motor that is interposed between the airframe and the landing gear structure and that extends and retracts along an axis to store the landing gear structure in the airframe and to deploy the landing gear structure from the airframe
Data Source
Figure 1
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AI summary
A landing gear (1) for an aircraft includes: a landing gear structure (2) attached to an airframe (10); a linear motor (3) that is interposed between the airframe and the landing gear structure and configured to extend and retract along an axis X to store the landing gear structure in the airframe and to deploy the landing gear structure from the airframe; and a controller (4) configured to control the linear motor such that the landing gear structure switches between a landing position and a retracted position.