Embedded Rotor Core Structure for High-Flux Disc PM Motors
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Solution Overview
Problem
Conventional disc permanent magnet motors face issues with low air gap magnetic flux density, large inertia, and complex assembly processes due to surface-mounted magnetic structures, which often require increased thickness and radial enlargement for torque, leading to conflicts and potential friction.
Innovation Solution
A rotor design comprising a first and second rotor core with embedded magnetic blocks and tiles, featuring axial and radial magnetic fields, and simplified assembly to enhance magnetic field density and reduce torque ripple, while allowing consistent magnetization without polarity distinction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the thickness of surface mounted magnetic steel is increased to improve air gap magnetic flux density, then magnetic flux density is improved, but magnetic steel utilization rate decreases
Solution Approach 1:
The patent transitions from conventional surface-mounted axial magnetic field structure to a built-in radial magnetic field structure. The magnetic steel is embedded in the rotor core with magnetization direction along the radial direction, changing the dimensional arrangement of magnetic field generation. This allows effective magnetic flux density without requiring excessive magnetic steel thickness, thereby improving magnetic steel utilization rate while maintaining or enhancing air gap magnetic flux density.
2Force
If radial size is enlarged to increase torque, then torque is improved, but inertia increases
Solution Approach 1:
The patent changes the magnetic field configuration from axial to radial direction, and embeds magnetic steel within the rotor core rather than mounting on the surface. This parameter change in magnetic field arrangement allows for more compact rotor design, increasing torque density without proportionally increasing rotor radius, thereby controlling moment of inertia while enhancing torque output capability.
3Power
If built-in arc-shaped permanent magnet structure with N-S-N-S arrangement is used, then magnetic field is formed, but assembly process becomes complicated due to polarity distinction requirement
Solution Approach 1:
The patent employs magnetic steel blocks with asymmetric polarized structures where alternating polarity is achieved through asymmetric magnetization arrangement. The magnetic steel blocks are magnetized such that adjacent blocks have opposite polarity, but the asymmetric design allows uniform assembly without requiring complex polarity identification during assembly, simplifying the manufacturing process while maintaining effective magnetic field formation.
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 design increases magnetic field density, simplifies assembly, reduces torque ripple, and improves motor stability and efficiency, while minimizing manufacturing complexity and potential friction.
Implementation Method 1
each of the plurality of second magnetic blocks comprises two sides, and a first side groove and a second side groove are respectively formed between the two sides and two adjacent first magnetic blocks; an axial thickness H1 of the second magnetic blocks is smaller than an axial thickness H2 of the first magnetic blocks, so that a first top surface of the second magnetic blocks is lower than a second top surface of two adjacent first magnetic blocks, thereby forming a top groove on the second magnetic blocks
Data Source
AI summary
A rotor for a disc permanent magnet motor, includes: a first rotor core; a second rotor core; and a plurality of magnetic tiles. The first rotor core includes a first annular ring and a plurality of first magnetic blocks protruding at intervals from an outer side of the first annular ring in a circumferential direction, and a first groove is formed between every two adjacent first magnetic blocks. The second rotor core includes a second annular ring and a plurality of second magnetic blocks protruding at intervals from an outer side of the second annular ring in a circumferential direction, and a second groove is formed between every two adjacent second magnetic blocks. The first rotor core and the second rotor core are axially embedded with each other. The first magnetic blocks are embedded in the second grooves. The second magnetic blocks are embedded in the first grooves.