Aircraft Landing Gear Torque Link Active Damping

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Solution Overview

Problem

Current passive shimmy oscillation dampening systems in aircraft landing gear, such as friction and hydraulic dampeners, face issues like fluid leakages, high maintenance, and limited applicability, necessitating an active and reliable solution to reduce vibration transmission and extend component lifespan.

Innovation Solution

A torque link assembly with an electric motor assembly and sensor system that actively controls the joint pin to dampen shimmy oscillations by translating it linearly, using a solenoid motor and ferromagnetic components to exert force and restrict vibration travel, integrated with a health monitoring system for data recording and maintenance insights.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydraulic dampeners are used to dampen shimmy oscillations, then damping effectiveness is improved, but reliability deteriorates due to increased risk of fluid leakages

Engineering Contradiction:
Improvedamping system reliabilityVSAvoidfluid leakage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the hydraulic dampening system with an electric motor assembly that uses electromagnetic forces to dampen shimmy oscillations. The electric motor assembly generates a damping force through electromagnetic interaction between the stator and rotor, eliminating the need for hydraulic fluid and associated leakage risks while maintaining effective damping performance.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If friction dampeners are used to dampen shimmy oscillations, then damping effectiveness is improved, but maintenance requirements increase due to high wear and tear

Engineering Contradiction:
Improvedamping system reliabilityVSAvoidmaintenance frequency
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The patent replaces the friction-based dampening mechanism with an electromagnetic damping system. The electric motor assembly uses magnetic fields to generate damping forces, eliminating mechanical friction between moving parts. This substitution dramatically reduces wear and tear, extending component lifespan and reducing maintenance frequency while maintaining effective shimmy damping.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Speed

If passive dampening systems are used, then system complexity is reduced, but response speed deteriorates

Engineering Contradiction:
Improveresponse rateVSAvoidsystem complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The patent implements an active dampening system with an electric motor assembly that can dynamically adjust its damping force in real-time. The system includes a sensor that detects shimmy oscillation characteristics and feeds this information to the electric motor assembly, enabling adaptive response. This dynamic control allows the system to optimize damping performance based on actual vibration conditions, achieving fast response rates while managing complexity through intelligent control rather than passive fixed-parameter designs.

Inventive Principle:
Principle #15Dynamics

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 active system effectively reduces the transmission of shimmy oscillations, decreases maintenance needs, and extends the lifespan of aircraft components by providing precise vibration control and real-time monitoring, outperforming hydraulic systems in response rate and reliability.

Implementation Method 1

an electric motor assembly configured to linearly translate the joint pin with respect to one of the upper or lower torque links

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

The electric motor can be fixed relative to the lower torque link. When the electric motor is fixed relative to the lower torque link, the sensor can be attached to the motor and monitor a sensor target on the lower torque link

Methodology Applied
Scientific EffectSolenoid magnetic force: Solenoid

Implementation Method 3

The joint pin can comprise an outer sleeve which comprises a ferromagnetic material

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Data Source

PatentEP4294721B1Aircraft landing gear torque link assembly
Publication Date: 2024.12.18 MESSIER DOWTY
  • EP4294721B1 patent drawingFigure 1
  • EP4294721B1 patent drawingFigure 2
  • EP4294721B1 patent drawingFigure 3

AI summary

A torque link assembly for an aircraft landing gear comprising: an upper torque link; a lower torque link; a joint pin arranged to pivotally couple the upper torque link and lower torque link; an electric motor assembly; a sensor arranged to detect movement of the upper torque link or lower torque link and in response to detecting the movement providing a control signal to the electric motor assembly, wherein the electric motor assembly is configured to linearly translate the joint pin with respect to one of the upper or lower torque links.