Hollow Cylindrical Magnet for Magnetic Angle Encoder

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Solution Overview

Problem

Existing magnetic angle encoders for electronic water meters are not compatible with tunneling magnetoresistive sensors due to differences in magnetic field detection orientation and cylindrical permanent magnet designs, which hinder accurate angle measurement and integration within counting wheels.

Innovation Solution

A cylindrical ring permanent magnet design with magnetization units oriented in antiparallel directions, producing a magnetic field component parallel to the detection plane, allowing a linear relationship between the magnetic phase angle and physical rotation angle, suitable for tunneling magnetoresistive sensors, and adaptable for embedding within counting wheels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a solid cylindrical permanent magnet is used, then the magnetic field is strong, but it cannot be installed within the counting wheel since the axle must pass through the center

Engineering Contradiction:
Improvemagnetic field strengthVSAvoidinstallation compatibility with counting wheel
Core Design Contradiction:
ForceVSEase of manufacture

Solution Approach 1:

The permanent magnet is segmented into a hollow cylindrical structure with an axial bore, dividing the solid magnet into a configuration that accommodates the counting wheel axle while maintaining magnetic functionality. This segmentation allows the magnet to be installed within the counting wheel without requiring the axle to pass through the magnet itself.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If existing permanent magnet designs are used, then the structure is simple, but they are not compatible with tunneling magnetoresistive sensors which detect magnetic field components parallel to the sensor surface

Engineering Contradiction:
Improvemagnet structure simplicityVSAvoidcompatibility with tunneling magnetoresistive sensors
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The permanent magnet employs localized magnetization regions with specific orientation patterns that create magnetic field components parallel to the detection plane. By configuring magnetized regions to produce the required field orientation, the magnet becomes compatible with tunneling magnetoresistive sensors while maintaining structural simplicity.

Inventive Principle:
Principle #3Local quality

3Force

If the permanent magnet is positioned close to the sensor, then the magnetic field signal is strong, but the space for sensor installation is limited

Engineering Contradiction:
Improvemagnetic field signal strengthVSAvoidsensor installation space
Core Design Contradiction:
ForceVSArea of stationary object

Solution Approach 1:

The hollow cylindrical magnet structure utilizes the axial dimension to create magnetic field components that extend parallel to the detection plane. This dimensional approach allows the magnet to generate sufficient magnetic field strength while providing adequate radial and axial clearance for sensor installation, effectively using three-dimensional space optimization.

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 design enhances measurement accuracy, reduces space requirements, and ensures compatibility with tunneling magnetoresistive sensors, enabling precise angle measurement and improved performance in electronic water meters.

Implementation Method 1

A cylindrical ring permanent magnet design with magnetization units oriented in antiparallel directions, producing a magnetic field component parallel to the detection plane

Methodology Applied
Scientific EffectMagnetism: Magnetism

Implementation Method 2

tunneling magnetoresistive sensors detect the magnetic field component parallel to the surface of the sensor

Methodology Applied
Scientific EffectTunneling magnetoresistance: Magnetoresistance

Data Source

PatentEP2942794B1Permanent magnet suitable for magnetic angle encoder
Publication Date: 2018.07.11 MULTIDIMENSION TECH CO LTD
  • EP2942794B1 patent drawingFigure 1~3
  • EP2942794B1 patent drawingFigure 4~5
  • EP2942794B1 patent drawingFigure 6~7

AI summary

The present invention relates to a permanent magnet suitable for a magnetic angle encoder. The permanent magnet (100, 300) has a cylindrical ring structure and comprises a first permanent magnet unit (101, 301) and a second permanent magnet unit (102, 302). The first permanent magnet unit (101, 301) and the second permanent magnet unit (102, 302) are geometrically symmetrical with respect to a diametral cross section (110, 310). The magnetization intensity (103, 303) of the first permanent magnet unit (101, 301) and the magnetization intensity (104, 304) of the second permanent magnet unit (102, 302) are parallel to the axial direction of the cylindrical ring and are in opposite directions, or the magnetization intensity (103, 303) of the first permanent magnet unit (101, 301) and the magnetization intensity (104, 304) of the second permanent magnet unit (102, 302) are perpendicular to the diametral cross section (110, 310) and are parallel to one another and in the same direction.