Bias Magnet Grooves for Magnetic Field Detection Precision

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional magnetic field detection apparatuses require a high accuracy assembly process to minimize the component of the bias magnetic field parallel to the magnetic pole surface, leading to increased costs due to the limited area where this reduction is effective.

Innovation Solution

A magnetic field detection apparatus with a bias magnet featuring a plurality of grooves arranged in the direction parallel to the magnetic pole surface, which limits and reverses the gradient of the bias magnetic field component, reducing its parallel component over a wider area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the magnetic sensor is disposed in a limited area to minimize the parallel component of the bias magnetic field, then the measurement precision is improved, but the device complexity and assembly cost increase due to high accuracy assembly requirements

Engineering Contradiction:

Improvemeasurement precisionVSAvoiddevice complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The magnetic pole surface is divided into multiple local regions with different characteristics. By creating grooves at specific locations, the magnetic field distribution is locally modified to reduce the parallel component in the sensor disposal area, while maintaining perpendicular field lines in other regions. This allows the sensor to be disposed in a wider area without compromising measurement precision.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The magnetic pole surface is segmented into multiple regions by introducing grooves. This segmentation creates distinct magnetic field zones where the parallel component is reduced in the regions where sensors are disposed, while other regions maintain their original field characteristics. This enables multiple sensors to be disposed across a wider area with consistent performance.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If the magnetic sensor is disposed in a limited area to minimize the parallel component of the bias magnetic field, then the measurement precision is improved, but the manufacturing cost increases due to high accuracy assembly requirements

Engineering Contradiction:

Improvemeasurement precisionVSAvoidease of manufacture

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The grooves are strategically positioned to create local modifications in the magnetic field distribution. This local quality change reduces the parallel component of the bias magnetic field in the specific regions where sensors are disposed, allowing sensors to be placed in a wider area without requiring high precision assembly, thereby reducing manufacturing costs.

Inventive Principle:

Principle #3Local quality

3Measurement precision

If the bias magnetic field is directed perpendicular to the magnetic pole surface at the center, then the parallel component is reduced at the center position, but the parallel component increases at positions away from the center

Engineering Contradiction:

Improvemeasurement precisionVSAvoidarea of moving object

Core Design Contradiction:

Measurement precisionVSArea of moving object

Solution Approach 1:

The magnetic pole surface is segmented by introducing grooves that divide the surface into multiple magnetic field zones. This segmentation creates regions where the magnetic field lines are redirected to reduce the parallel component, extending the area where sensors can be disposed with acceptable performance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The grooves create local modifications in the magnetic field distribution pattern. By strategically positioning these grooves, the parallel component of the magnetic field is reduced in specific regions away from the center, expanding the usable area for sensor disposal while maintaining measurement precision.

Inventive Principle:

Principle #3Local quality

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 configuration allows for a wider area of reduced bias magnetic field parallel to the magnetic pole surface, enhancing the accuracy and reducing the assembly complexity and costs of the magnetic field detection apparatus.

Implementation Method 1

The magnetic sensor generally has a magneto-resistive effect element that utilizes the magneto-resistive effect

Methodology Applied

Scientific EffectMagneto-resistive effect: Magnetoresistance

Implementation Method 2

The grooves that are provided on the magnetic pole surface of the bias magnet limit or reverse the gradient of the component of the bias magnetic field in the first direction

Methodology Applied

Scientific EffectMagnetic field distribution control: Magnetic Field

Data Source

PatentUS10082406B2Magnetic field detection apparatus and rotation detection apparatus

Publication Date: 2018.09.25 TDK CORP

AI summary

A magnetic field detection apparatus has a first magnetic sensor and a bias magnet positioned to face the first magnetic sensor. The bias magnet has a magnetic pole surface that faces the first magnetic sensor and that applies a bias magnetic field to the first magnetic sensor. The first magnetic sensor detects magnetic field in a first direction that is parallel to the magnetic pole surface. The magnetic pole surface of the bias magnet has a plurality of grooves arranged in the first direction.