Magnetic Field Sensor Device for Torque Measurement

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Solution Overview

Problem

Existing torque and force measurement technologies face inefficiencies and inaccuracies, particularly in non-contacting measurements, and often require magnetizable objects or permanent magnetic fields, which can limit their application and reliability.

Innovation Solution

A sensor device utilizing a magnetic field generator and detectors that applies a direct current or voltage to create a reversible magnetic field, allowing for accurate measurement of torque and forces without the need for magnetizable objects, enabling efficient and portable measurement of mechanical forces like torque, bending, and axial loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If current pulses with steep rising edge and slow falling edge are applied to measure torque, then measurement can be performed, but measurement accuracy and reliability deteriorate

Engineering Contradiction:
Improvetorque measurement accuracyVSAvoidsensor operation reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent applies periodic current pulses with a specific duty cycle (steep rising edge, slow falling edge) to the magnetic field generator. This periodic excitation creates a time-varying magnetic field that induces measurable voltages in the detector coil during the steep rising phase, while the slow falling phase allows magnetic field relaxation. This temporal modulation separates the measurement signal from background noise and hysteresis effects, improving both accuracy and reliability of torque measurements.

Inventive Principle:
Principle #19Periodic action

2Reliability

If permanent magnets or permanently magnetized objects are used, then magnetic field is available for measurement, but application flexibility and portability are limited

Engineering Contradiction:
Improvemagnetic field stabilityVSAvoidapplication flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces static permanent magnets with a dynamic electromagnetic field generator that can be activated only when needed. The magnetic field is generated on-demand through controlled current pulses, allowing the sensor to transition between active measurement states and inactive standby states. This dynamic approach provides permanent magnet stability during measurement while enabling portability and flexibility for various measurement scenarios including hand-held operation and different mounting positions.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If the sensor device is positioned at a distance from the object, then ease of operation is improved, but magnetic field transfer efficiency and measurement accuracy deteriorate

Engineering Contradiction:
Improvesensor positioning flexibilityVSAvoidmeasurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent employs very short current pulse durations (microsecond to millisecond range) with steep rising edges to rapidly establish the magnetic field and complete the measurement process before magnetic field diffusion and hysteresis effects can degrade signal quality. This 'rushing through' the measurement process in a brief time window allows adequate signal strength even at increased sensor-object distances, maintaining accuracy while improving operational ease.

Inventive Principle:
Principle #21Skipping (Rushing through)

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 solution provides high accuracy and efficiency in measuring mechanical forces, is applicable to both static and dynamic objects, and does not require permanent magnetization, offering a flexible and cost-effective solution for various industrial applications.

Implementation Method 1

A sensor device is provided which includes a magnetic field generator and one or more magnetic field detectors... applies a direct current or voltage to create a reversible magnetic field

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP1920221B1Sensor device, sensor arrangement, and method of measuring a property of an object
Publication Date: 2021.07.21 NCTE
  • EP1920221B1 patent drawingFigure 1~2
  • EP1920221B1 patent drawingFigure 3~6
  • EP1920221B1 patent drawingFigure 7~8

AI summary

A sensor device for measuring a property of an object, the sensor device comprising a magnetic field generator adapted to generate a magnetic field in at least a part of the object, and at least one magnetic field detector adapted to detect at least one detection signal in response to the magnetic field generated in at least a part of the object, wherein the at least one detection signal is indicative of the property of the object, wherein a direct current or a direct voltage is applicable to the magnetic field generator to generate the magnetic field in at least a part of the object.