Magnetic Incremental Encoder With Contactless Notching

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Solution Overview

Problem

Existing encoders for aeronautical applications face issues with friction, wear, complexity, and misalignment between detection and notching functions, leading to reduced reliability and limited service life, especially in opto-mechanical and electromechanical solutions.

Innovation Solution

An incremental magnetic encoder design that uses magnetic alternation between a fixed and movable body to implement encoding and notching without mechanical contact, minimizing friction and wear, and allowing simultaneous detection and notching along multiple directions using magnetic detectors and ferromagnetic or magnetic notching teeth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If opto-mechanical or electromechanical encoders are used, then detection and notching functions can be implemented, but friction and wear occur reducing reliability and service life

Engineering Contradiction:

Improveencoder reliabilityVSAvoidservice life

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent replaces mechanical contact-based detection and notching systems with a magnetic field-based system. Magnetic detectors sense position through magnetic field variations, and magnetic notching teeth create detents without physical contact, eliminating friction and wear while maintaining detection and notching functions

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces magnetic fields as an intermediary between the movable body and fixed body. Magnetic detectors detect position through magnetic field changes, and magnetic notching teeth interact with the magnetic field to create notching effects without direct mechanical contact, serving as a non-contact mediator

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If detection and notching functions are implemented separately, then each function can be optimized, but device complexity and part count increase

Engineering Contradiction:

Improvedetection functionVSAvoidencoder complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the magnetic field-based system perform multiple functions: the same magnetic detectors used for position detection also sense magnetic notching teeth for notching feedback, and the movable body's magnetic elements serve both detection and notching purposes, eliminating the need for separate mechanical detection and notching mechanisms

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the detection system and notching system into a single integrated magnetic field-based mechanism. Magnetic detectors and magnetic notching teeth work together within the same magnetic field environment, combining what were previously separate functions into one unified system

Inventive Principle:

Principle #5Merging (Combining)

3Force

If mechanical notching teeth are used, then notching force can be achieved, but friction and wear occur

Engineering Contradiction:

Improvenotching forceVSAvoidfriction and wear

Core Design Contradiction:

ForceVSObject-generated harmful factors

Solution Approach 1:

The patent replaces mechanical contact-based notching with a magnetic field-based notching system. Magnetic notching teeth create detent forces through magnetic field interactions rather than mechanical contact, eliminating friction and wear while maintaining the notching force needed for tactile feedback

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 encoder achieves reliable operation with extended service life, reduced part count, simplified assembly, and compact design, ensuring high torque and notching force without increasing size, suitable for aeronautical applications.

Implementation Method 1

the first ring defining a magnetic alternation along the first direction of encoding

Methodology Applied

Scientific EffectMagnetic alternation: Magnetic Field

Implementation Method 2

a first pair of magnetic detectors arranged opposite the first ring and configured for quantifying each movement of the movable body along the first direction of encoding

Methodology Applied

Scientific EffectMagnetic detection: Magnetic Field

Implementation Method 3

at least one first notching tooth made of ferromagnetic or magnetic material arranged opposite the first ring so as to create a notching during a movement of the movable body along the first direction of encoding

Methodology Applied

Scientific EffectMagnetic notching: Magnetism

Data Source

PatentUS12429361B2Incremental magnetic encoder

Publication Date: 2025.09.30 THALES SA

AI summary

An incremental magnetic encoder is provided which defines an encoder axis and which as a fixed body and a body movable with respect to the fixed body along at least a first direction of encoding. One of the bodies, called first body, has a first ring extending along a first longitudinal direction coinciding with an encoder axis and a first circumferential direction perpendicular to the first longitudinal direction, and defining a magnetic alternation along the first direction of encoding. The other body, called second body, has at least one first notching tooth made of ferromagnetic or magnetic material arranged opposite the first ring, and a first pair of magnetic sensors arranged opposite the first ring and configured for quantifying each movement of the movable body along the first direction of encoding.