Rotor Magnet Position Sensing in Axial Magnetic Sensor Motors

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Solution Overview

Problem

Existing rotary machines require position detecting magnets to detect the rotor's position, which adds complexity and components to the system.

Innovation Solution

A rotary machine design that uses a magnetic sensor arranged to face the rotor in an axial direction parallel to the rotary shaft, detecting the rotor's position based on the magnetic field generated by a plurality of magnets integrated into the rotor, eliminating the need for additional position detecting magnets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If position detecting magnets are added to detect rotor position, then measurement precision is improved, but device complexity increases

Engineering Contradiction:

Improverotor position detectionVSAvoidsystem structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the position detecting magnet function with the existing rotor magnets that generate the magnetic field for motor operation. By integrating these functions into a single magnet structure, the system achieves accurate position detection without adding separate position detecting magnets, thus reducing device complexity while maintaining measurement precision

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The rotor magnets serve dual purposes: generating the magnetic field necessary for motor operation and providing the magnetic field signals required for position detection. This multi-functional design eliminates the need for dedicated position detecting magnets, simplifying the overall system structure

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If position detecting magnets are added to detect rotor position, then measurement precision is improved, but manufacturing cost increases

Engineering Contradiction:

Improverotor position detectionVSAvoidmanufacturing process

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges the position detection function with the existing rotor magnet assembly. Since the position detecting magnet is integrated into the rotor magnet structure that already exists for motor operation, no additional manufacturing steps or materials are required, thereby avoiding increased manufacturing costs while achieving accurate position detection

Inventive Principle:

Principle #5Merging (Combining)

3Measurement precision

If additional position detecting magnets are installed, then rotor position detection is improved, but disturbance to rotor magnetic field increases

Engineering Contradiction:

Improverotor position detectionVSAvoidmagnetic field disturbance

Core Design Contradiction:

Measurement precisionVSObject-generated harmful factors

Solution Approach 1:

The patent combines the position detection function with the existing rotor magnets, eliminating the need for separate position detecting magnets. This integration avoids additional magnetic field sources that would cause disturbance, while still providing accurate position detection signals through the unified magnet structure

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The rotor magnets serve themselves by simultaneously providing both the motor operating magnetic field and the position detection signals. This self-service approach eliminates the need for additional position detecting magnets that would create magnetic field disturbances, as the existing magnets fulfill both functions without interference

Inventive Principle:

Principle #25Self-service

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 simplifies the system by eliminating the need for additional position detecting magnets and reduces potential disturbances, while effectively detecting the rotor's position using the magnetic field, applicable to various types of rotary machines.

Implementation Method 1

The magnetic sensor detects the position of the rotor based on a magnetic field generated by the plurality of magnets of the rotor

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentUS20250007360A1Rotary machine, method for manufacturing the rotary machine, and magnetic sensor

Publication Date: 2025.01.02 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A rotary machine according to the present disclosure includes a stator, a rotor, a rotary shaft, and a magnetic sensor. The rotor rotates relative to the stator. The rotary shaft is coupled to the rotor and rotates as the rotor rotates. The magnetic sensor detects a position of the rotor. The rotor includes a plurality of magnets. The magnetic sensor is arranged to face the rotor in an axial direction that is parallel to the rotary shaft. The magnetic sensor detects the position of the rotor based on a magnetic field generated by the plurality of magnets of the rotor.