Aircraft Eddy Current Brake Magnet Layout for Higher Torque

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Solution Overview

Problem

Eddy current magnetic braking devices for aircraft wheels are heavy and bulky due to the high power requirements, which contradicts the mass and size constraints for aircraft applications.

Innovation Solution

The arrangement of magnets with specific dimensions and orientations, such as Halbach pattern, optimizes magnetic flux concentration and reduces the return path, increasing braking torque while minimizing device mass and size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If high power magnets are used to increase braking torque, then braking performance is improved, but device mass and size increase

Engineering Contradiction:
Improvebraking torqueVSAvoiddevice mass
Core Design Contradiction:
ForceVSWeight of moving object

Solution Approach 1:

The magnet array is segmented into first magnets and second magnets with different dimensions and orientations. The first magnets have larger dimensions and are oriented to generate primary magnetic flux, while the second magnets have smaller dimensions and are oriented to redirect flux, creating a segmented approach that optimizes the magnetic field distribution and reduces overall magnet mass while maintaining braking torque.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the magnet array have different local qualities - the first magnets have larger dimensions and specific orientation to generate strong magnetic flux in certain areas, while the second magnets have smaller dimensions and different orientation to modify flux distribution in other areas. This local differentiation allows optimization of magnetic flux concentration without requiring uniformly high-power magnets throughout the entire array.

Inventive Principle:
Principle #3Local quality

2Force

If high power magnets are used to increase braking torque, then braking performance is improved, but device size increases

Engineering Contradiction:
Improvebraking torqueVSAvoiddevice size
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The magnet array is segmented into first magnets and second magnets with different dimensions and orientations. The first magnets have larger dimensions and are oriented to generate primary magnetic flux, while the second magnets have smaller dimensions and are oriented to redirect flux, creating a segmented approach that optimizes the magnetic field distribution and reduces overall magnet mass while maintaining braking torque.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the magnet array have different local qualities - the first magnets have larger dimensions and specific orientation to generate strong magnetic flux in certain areas, while the second magnets have smaller dimensions and different orientation to modify flux distribution in other areas. This local differentiation allows optimization of magnetic flux concentration without requiring uniformly high-power magnets throughout the entire array.

Inventive Principle:
Principle #3Local quality

3Force

If conventional magnet arrangement is used, then device structure is simple, but magnetic flux concentration is insufficient

Engineering Contradiction:
Improvemagnetic flux concentrationVSAvoidmagnet arrangement complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The magnet array employs asymmetric arrangement where first magnets and second magnets have different dimensions, orientations, and spacing. The first magnets have larger dimensions and are spaced at a first pitch, while the second magnets have smaller dimensions and are spaced at a second pitch. This asymmetric configuration creates optimized magnetic flux concentration patterns that would not be achievable with uniform symmetric arrangements.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention introduces dimensional variation in the magnet array by using magnets with different orientations (first orientation and second orientation perpendicular to the first). This dimensional change in the magnetic field configuration allows for optimized flux concentration through the conductive element while managing the complexity through systematic dimensional variation rather than uniform scaling.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

This configuration enhances braking torque while reducing the device's mass and size, making it suitable for aircraft applications.

Implementation Method 1

one of the elements comprising a plurality of magnets capable of generating eddy currents in the other of the elements, made of electrically conductive material, when the two elements are in relative movement

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 2

at least one fixed element and one element movable relative to the fixed element... one of the elements comprising a plurality of magnets capable of generating eddy currents

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4334159B1Magnetic eddy current braking device, braked vehicle wheel and aircraft landing gear equipped with such a wheel
Publication Date: 2025.09.10 SAFRAN LANDING SYSTEMS
  • EP4334159B1 patent drawingFigure 1
  • EP4334159B1 patent drawingFigure 2
  • EP4334159B1 patent drawingFigure 3

AI summary

Disclosed is an eddy current magnetic braking device that comprises stationary elements (2) and movable elements (3) having opposite surfaces (2.1), wherein one element (2) of the stationary and movable elements comprises a plurality of magnets (11, 12, 13, 14) capable of generating eddy currents in the other element (3), the latter being made of electrically conductive material. The plurality of magnets includes first magnets (11, 13) that have a first magnetization vector substantially perpendicular to the opposite surfaces (2.1, 3.1) and are separated in pairs by a second magnet (12, 14) having a second magnetization vector substantially perpendicular to the first magnetization vectors of the two first magnets between which the second magnet is located. The magnets (11, 12, 13, 14) have widths such that the first magnets (11, 13) are spaced apart in pairs by a first distance less than a second distance by which the second magnets (12, 14) are separated in pairs. The invention further relates to an aircraft wheel and landing gear comprising such a device.