Linear Eddy-Current Sensor for Precise Motion Detection

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Solution Overview

Problem

Existing rotation sensors are not effectively adapted for detecting linear movements or distances, limiting their application to rotational movements and angles.

Innovation Solution

A linear sensor design utilizing a first electromagnetic coil as an excitation coil, at least one receiver coil, and a conductive coupling element, allowing for the detection of linear movements by generating eddy currents that vary voltage in the receiver coils, with specific coil configurations and a movable coupling element.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If rotation sensor components are used for linear detection, then existing proven technology can be leveraged, but the sensor cannot detect linear movements effectively

Engineering Contradiction:
Improveapplication fieldVSAvoidlinear detection accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent transforms the static rotational detection geometry into a dynamic linear detection geometry by allowing the coupling element to move linearly relative to the coils, enabling the same electromagnetic field interaction mechanism to serve both rotational and linear detection applications

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the geometric parameters of the coil arrangement and coupling element configuration from rotational to linear geometry, specifically arranging coils and coupling element in a linear configuration where the coupling element can translate along a linear path, thereby adapting the sensor for linear movement detection

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If rotation sensor design is modified for linear detection, then linear movement detection becomes possible, but device complexity increases

Engineering Contradiction:
Improvedetection typeVSAvoidsensor structure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent creates a universal sensor platform where the same basic electromagnetic field interaction components (coils and coupling element) can be configured for either rotational or linear detection applications, reducing overall system complexity by using a common design foundation

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent divides the sensor into distinct functional segments: the first part containing excitation and receiver coils, and the second part containing the coupling element, allowing independent optimization and simplification of each segment while maintaining overall functionality

Inventive Principle:
Principle #1Segmentation

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

Enables accurate and simplified detection of linear distances and movements by modifying existing rotation sensor components, enhancing precision and ease of detection.

Implementation Method 1

a first part with a first electromagnetic coil as excitation coil... into which an electromagnetic field generated by said excitation coil can be coupled

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

eddy currents can be generated in said coupling element

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Implementation Method 3

eddy currents can be generated in said coupling element which generate an electromagnetic field which can be coupled into said at least one receiver coil to vary a voltage applied to said at least one receiver coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4065935B1Linear motion sensor
Publication Date: 2025.12.31 HELLA GMBH & CO KGAA
  • EP4065935B1 patent drawingFigure 1~3

AI summary

The invention relates to a linear sensor for detecting a length or a linear movement the linear sensor comprising - a first part - having a first electromagnetic coil as excitation coil and - having at least one second electromagnetic coil as receiver coil that en- closes a first surface, and a second part - having an electrically conductive coupling element, - into which an electromagnetic field generated by the excitation coil can be coupled, - whereby eddy currents can be generated in the coupling element which generate an electromagnetic field - which can be coupled into the at least one receiver coil in order to change a voltage applied to the at least one receiver coil, the second part being linearly movable relative to the first part.