Gear Rotation Sensing With Shared Magnet Redundancy

Solution Overview

Problem

Existing rotation detection apparatuses face challenges in achieving redundancy without increasing size and cost, particularly in ABS devices, where adding or enlarging magnets is necessary to accommodate multiple MR elements, leading to size and cost increments.

Innovation Solution

A rotation detection apparatus comprising two sensor portions with magnetic detection elements and a shared permanent magnet, where the sensor portions are arranged with different spacings relative to the magnet's surfaces, allowing for redundancy without size or cost increments, and housed in a resin molded body.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the number of magnets is increased or the size of the magnet is increased to accommodate multiple MR elements, then redundancy is achieved, but the size and cost of the rotation detection apparatus increase

Engineering Contradiction:

ImproveredundancyVSAvoidsize of apparatus

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

Multiple sensor portions (first sensor portion and second sensor portion) share a single permanent magnet, merging the magnetic field source that would traditionally be duplicated. This combining approach enables redundancy through multiple sensors while avoiding the size and cost increase that would result from multiple magnets

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single permanent magnet serves multiple functions by providing magnetic field support to both the first sensor portion and the second sensor portion simultaneously. This multi-functionality allows one magnet to enable redundancy for multiple sensors without requiring separate magnets for each sensor

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If the number of magnets is increased or the size of the magnet is increased to accommodate multiple MR elements, then redundancy is achieved, but the cost of the rotation detection apparatus increases

Engineering Contradiction:

ImproveredundancyVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Multiple sensor portions (first sensor portion and second sensor portion) share a single permanent magnet, merging the magnetic field source that would traditionally be duplicated. This combining approach enables redundancy through multiple sensors while avoiding the size and cost increase that would result from multiple magnets

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The single permanent magnet serves multiple functions by providing magnetic field support to both the first sensor portion and the second sensor portion simultaneously. This multi-functionality allows one magnet to enable redundancy for multiple sensors without requiring separate magnets for each sensor

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Measurement precision

If multiple magnets are arranged behind each MR element, then each sensor has sufficient magnetic field, but the apparatus size increases

Engineering Contradiction:

Improvemagnetic field detectionVSAvoidapparatus size

Core Design Contradiction:

Measurement precisionVSVolume of stationary object

Solution Approach 1:

Multiple sensor portions (first sensor portion and second sensor portion) share a single permanent magnet, merging the magnetic field source that would traditionally be duplicated. This combining approach enables redundancy through multiple sensors while avoiding the size and cost increase that would result from multiple magnets

Inventive Principle:

Principle #5Merging (Combining)

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 enables redundancy in rotation detection without increasing the apparatus's size or cost, ensuring reliable operation in ABS devices by equalizing the output of the sensor portions and preventing misalignment during assembly.

Implementation Method 1

a first sensor portion and a second sensor portion each having a magnetic detection element... one permanent magnet arranged between the first sensor portion and the second sensor portion... detect a rotation state of an object-to-be-detected based on a magnetic field change

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentUS11764649B2Rotation detection apparatus

Publication Date: 2023.09.19 PROTERIAL LTD

AI summary

The present invention relates to a rotation detection apparatus configured to detect a rotation state of a gear based on a magnetic field change that occurs as the gear is rotated. The rotation detection apparatus includes: a first sensor portion and a second sensor portion each having a magnetic detection element and a covering member configured to cover the magnetic detection element; one permanent magnet arranged between the first sensor portion and the second sensor portion; and a housing portion configured to accommodate the first sensor portion, the second sensor portion and the permanent magnet.