Ring Magnet Curie Point Heating for Narrow Pitch Magnetization
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Solution Overview
Problem
Conventional magnetizing methods struggle to achieve sufficient magnetization characteristics for ring-shaped permanent magnets with narrow magnetization pitches and multiple poles on extremely small diameters, leading to inadequate magnetization quality and significant variations in surface magnetic flux density.
Innovation Solution
A magnetizing apparatus comprising a heating section and a magnetizing section, where the magnetization object is heated to a temperature above its Curie point and then transferred to the magnetizing section for magnetization, allowing for controlled temperature management to optimize magnetization, including the use of permanent magnets with higher Curie points and temperature control to prevent demagnetization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the diameter of the ring-shaped permanent magnet is reduced to achieve miniaturization, then the size of the stepping motor is reduced, but the magnetization pitch becomes narrow making it difficult to obtain sufficient magnetization characteristics
Solution Approach 1:
The patent applies parameter changes by heating the permanent magnet to a temperature above its Curie point before magnetization. This temperature parameter change reduces the magnetizing force required and enables sufficient magnetization characteristics to be achieved even with narrow magnetization pitches in miniaturized motors. The heating treatment modifies the magnetic properties of the material, allowing effective magnetization where conventional cold magnetization would fail.
2Device complexity
If conventional coil-energization magnetizing apparatus is used with narrow magnetization pitch, then the apparatus structure remains simple, but only a limited amount of electric current can be supplied resulting in insufficient magnetization
Solution Approach 1:
The patent changes the temperature parameter of the permanent magnet to above its Curie point, which fundamentally alters the magnetization process. This parameter change enables the use of permanent magnets for magnetization instead of relying solely on high-current coil energization, thereby achieving sufficient magnetization power without increasing apparatus complexity or electric current supply requirements.
Solution Approach 2:
The patent introduces a heating section as an intermediary component that prepares the permanent magnet for magnetization by heating it above the Curie point. This intermediary heating process enables the subsequent magnetization to be effective with limited current supply, resolving the contradiction between simple apparatus structure and sufficient magnetization power.
3Manufacturing precision
If permanent magnets are used for magnetization with narrow pitch, then insufficient magnetization is improved to a certain degree, but variation between peak values of surface magnetic flux density remains significant
Solution Approach 1:
The patent applies parameter changes by controlling the temperature of the permanent magnet during magnetization. By heating the magnet above its Curie point and maintaining controlled temperature conditions, the magnetization process achieves both high magnetization levels and uniform surface magnetic flux density distribution, eliminating the significant variations that occur with conventional methods.
4Manufacturing precision
If heating to above Curie point is applied to achieve sufficient magnetization, then magnetization quality is improved, but additional heating section and temperature control are required increasing device complexity
Solution Approach 1:
The patent applies segmentation by dividing the magnetizing apparatus into distinct functional sections: a heating section for heating the permanent magnet above the Curie point, and a magnetizing section for applying the magnetizing field. This segmentation allows each section to be optimized independently, achieving high magnetization quality while managing device complexity through modular functional division.
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 approach enables efficient and high-quality magnetization with improved average surface magnetic flux density and reduced variations, even at narrow pitches, while preventing initial demagnetization and maintaining stable magnetic characteristics across a range of temperatures.
Implementation Method 1
the magnetization object heated in the heating section is transferred to the magnetizing section and is magnetized therein
Implementation Method 2
an electric charge stored in a capacitor is instantaneously discharged, and thereby a pulse current passes through the coil to generate a magnetic field, which magnetizes the magnetization object
Implementation Method 3
a holding member for holding a magnetization object and that is movable relative to the heating section and the magnetizing section
Data Source
AI summary
To provide a magnetizing apparatus and magnetizing method in which, even in preparation of a ring-shaped permanent magnet having a narrow magnetization pitch with multiple poles magnetized on an extremely small diameter, sufficient magnetization and high magnetization quality can be achieved and powerful magnetization can be carried out efficiently and quickly at low cost.A permanent magnet magnetizing apparatus includes a heating section 10, a magnetizing section 12 axially disposed as a discrete structure from the heating section 10, and a holding member 22 for holding magnetization object 20 and movable relative to the heating section and the magnetizing section. The magnetization object heated in the heating section is transferred to the magnetizing section and is magnetized therein.