Rotor Magnetizing Coil Layout for Small-Diameter Multi-Pole Motors
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Solution Overview
Problem
Conventional magnetizing apparatuses struggle to effectively magnetize rotors with a smaller diameter and more poles due to a reduced magnetic circuit and increased magnetic field strength requirements, leading to higher manufacturing costs and reduced product lifetime.
Innovation Solution
A magnetizing method and apparatus using three magnetizing coils arranged in a Y-shaped configuration to generate radial inward and outward magnetic fields, ensuring high-intensity magnetic fields reach the interior of the rotor's magnetic bodies, reducing the need for high-current power supplies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the rotor diameter is reduced and the number of poles is increased to reduce motor size and increase output, then the motor size is reduced and output is increased, but the magnetic circuit for magnetizing permanent magnets becomes smaller and the magnetic flux hardly reaches the inside of the permanent magnets
Solution Approach 1:
The magnetizing coil is divided into multiple independent coils (first magnetizing coil, second magnetizing coil, third magnetizing coil) arranged at different angular positions around the rotor. Each coil independently generates magnetic flux that penetrates the rotor core and reaches the permanent magnets from different directions, ensuring adequate magnetization even in small-diameter rotors with reduced magnetic circuits.
Solution Approach 2:
Magnetizing coils are strategically positioned at specific angular locations (e.g., 0°, 120°, 240°) around the rotor perimeter. This localized arrangement ensures that magnetic flux is generated at critical positions where it can effectively penetrate the rotor core and reach the permanent magnets, addressing local magnetization needs in compact rotor designs.
2Manufacturing precision
If the magnetic field strength is increased to magnetize high-performance magnets, then the magnetization quality is improved, but the power supply capacity and electric current must be increased, resulting in shortened product lifetime and increased manufacturing costs
Solution Approach 1:
The total magnetization task is distributed across multiple magnetizing coils instead of relying on a single high-current coil. Each coil operates at lower current levels to generate magnetic flux from its specific angular position, collectively achieving the required magnetic field strength for high-performance magnets while reducing stress on individual components and extending product lifetime.
Solution Approach 2:
Instead of increasing magnetic field strength by increasing current in a single dimension, the solution adds spatial distribution as another dimension by arranging multiple coils at different angular positions around the rotor. This multi-dimensional approach achieves the required magnetic flux density through geometric arrangement rather than simply increasing electrical current.
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
The method and apparatus reliably magnetize the rotor's magnetic bodies, enhancing magnetic flux density and reducing manufacturing costs by concentrating magnetic fields within the rotor, even with a smaller diameter and more poles.
Implementation Method 1
a first magnetizing coil that is arranged near the outer peripheral portion of the hollow portion and generates a radially outward magnetic field, a second magnetizing coil that is arranged near the outer peripheral portion of the hollow portion, is arranged at a position apart from the first magnetizing coil in the circumferential direction, and generates a radially inward magnetic field
Data Source
AI summary
A magnetizing method applies, to a rotor including a plurality of magnetic bodies that are arranged in the circumferential direction of the rotor and are to be magnetized, a magnetic field in a radial direction of the rotor to magnetize the magnetic bodies. The magnetizing method includes a step of arranging a magnetizing coil near the outer peripheral portion of the plurality of magnetic bodies and a step of applying a radially outward magnetic field only to one of the magnetic bodies while applying radially inward magnetic fields to the plurality of magnetic bodies.