Magnetic Torque Sensor with Shielding for Transmission Converter

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Solution Overview

Problem

Existing torque sensing devices for disk-shaped members are prone to inaccuracies due to magnetic noise, compassing, and rotational signal uniformity issues, particularly when measuring torque between a shaft and a radially separated portion of a disk-shaped member, and require improvements in rotational signal uniformity and resistance to external magnetic fields.

Innovation Solution

A non-contacting magnetic torque sensing device with annularly shaped magnetically conditioned regions and multiple pairs of angularly spaced magnetic field sensors, positioned to minimize magnetic noise and enhance rotational signal uniformity, featuring dual oppositely polarized regions with no gap between them to improve accuracy and linearity of torque measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If non-contacting magnetic field sensors are used to measure torque, then reliability is improved, but measurement precision deteriorates due to magnetic noise and compassing

Engineering Contradiction:

ImprovereliabilityVSAvoidmeasurement precision

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies magnetic shielding materials to block external magnetic fields (harmful factor) from reaching the sensors, converting the harmful magnetic noise into a manageable condition. The shielding materials absorb or redirect external magnetic field lines, protecting the measurement system while allowing the sensors to function reliably

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent introduces magnetic shielding materials as an intermediary between the external magnetic field sources and the magnetic field sensors. This intermediary layer filters out harmful magnetic noise and compassing effects while allowing the torque-induced magnetic field changes to pass through to the sensors for accurate measurement

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If magnetically conditioned regions are separated by a gap, then ease of manufacture is improved, but measurement precision deteriorates due to reduced rotational signal uniformity

Engineering Contradiction:

Improveease of manufactureVSAvoidrotational signal uniformity

Core Design Contradiction:

Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent merges the two magnetically conditioned regions by eliminating the gap between them, creating a continuous magnetic field distribution around the shaft. This continuous configuration ensures uniform magnetic field strength at all angular positions, improving rotational signal uniformity while still allowing practical manufacturing through controlled magnetization processes

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If multiple pairs of angularly spaced sensors are used, then rotational signal uniformity is improved, but device complexity increases

Engineering Contradiction:

Improverotational signal uniformityVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs an asymmetric arrangement of magnetic shielding materials and magnetically conditioned regions that creates a dominant magnetic field direction. This asymmetric configuration allows the use of fewer sensors while maintaining rotational signal uniformity, as the asymmetric field distribution provides consistent signal characteristics across different angular positions

Inventive Principle:

Principle #4Asymmetry

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 accurate, linear torque measurements by reducing the impact of external magnetic fields and improving rotational signal uniformity, ensuring reliable and precise torque sensing without the limitations of previous technologies.

Implementation Method 1

a magnetoelastically active region which has been magnetized in a first direction to define a non-contacting magnetic field

Methodology Applied

Scientific EffectMagnetoelastic effect: Magnetoelastic Effects

Implementation Method 2

Upon the application of torsional stress to the shaft, the magnetization reorients and becomes increasingly helical as torsional stress increases

Methodology Applied

Scientific EffectMagnetostriction: Magnetostriction

Data Source

PatentEP2584331B1Magnetic torque sensor for transmission converter drive plate

Publication Date: 2018.05.09 METHODE ELECTRONICS INC

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Figure 4A~4B

AI summary

A magnetic torque sensing device having a disk-shaped member with a magnetoelastically active region. The magnetoelastically active region has oppositely polarized magnetically conditioned regions with initial directions of magnetization that are perpendicular to the sensitive directions of magnetic field sensor pairs placed proximate to the magnetically active region. Magnetic field sensors are specially positioned in relation to the disk-shaped member to accurately measure torque while providing improved RSU performance and reducing the detrimental effects of compassing.