Embedded Magnet Rotor Layout for Stable Magnet Positioning
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Solution Overview
Problem
The variability in the fixed position of permanent magnets within the accommodation holes of a rotor core in embedded magnet type rotors leads to unbalanced rotation, increased torque ripple, and decreased induced voltage, deteriorating motor characteristics.
Innovation Solution
The rotor core is designed with varying radial core thickness and divided magnets arranged in the circumferential direction, utilizing magnetic forces to bias and fix the magnets in position, eliminating the need for multiple adhesive types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If permanent magnets are housed in accommodation holes of rotor core, then the rotor can generate magnetic flux, but the fixed position of magnets varies within the accommodation hole leading to unbalanced rotation and increased torque ripple
Solution Approach 1:
The accommodation hole is divided into multiple regions by positioning magnets at specific locations (first and second positions) within the hole. This segmentation allows independent control of magnet positions to optimize both flux generation and position stability, reducing torque ripple caused by positional variations.
Solution Approach 2:
Different regions of the accommodation hole are designed with different magnetic properties by placing magnets at specific positions. The first magnet position optimizes for magnetic flux generation while the second position ensures stability and reduces variation, creating local quality differences that resolve the contradiction between flux generation and position stability.
2Reliability
If multiple adhesive types are used to fix magnets at different positions, then magnet position stability improves, but manufacturing process complexity increases
Solution Approach 1:
A single adhesive type is used to fix magnets at multiple different positions (first and second positions) within the accommodation hole. This universal approach simplifies the manufacturing process by eliminating the need to manage multiple adhesive types while still achieving stable magnet positioning through optimized placement geometry.
Solution Approach 2:
The same adhesive application process is copied and used for fixing magnets at different positions within the accommodation hole. This standardization of the fixing process across multiple positions reduces manufacturing complexity while maintaining position stability through the geometric arrangement of magnets.
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 effectively suppresses positional variations of the magnets, simplifies the manufacturing process, and enhances magnetic flux, resulting in improved rotor stability and performance.
Implementation Method 1
The two divided magnets are biased in the radial direction so as to be close to the first side surface on a side having a thicker radial core thickness among both radial sides of the accommodation hole, and are biased so as to be close to the second side surface in the circumferential direction
Data Source
AI summary
A rotor includes a rotor core and a plurality of magnets accommodated in each accommodation hole of the rotor core. The rotor core has a radial core thickness that is different on one side and the other side in a radial direction with the accommodation hole in between. The accommodation hole is formed surrounded by first side surfaces facing each other in a radial direction and second side surfaces facing each other in a circumferential direction. The magnet consists of two divided magnets arranged in the circumferential direction within the accommodation hole. The two divided magnets are biased in the radial direction so as to be close to the first side surface on a side having a thicker radial core thickness among both radial sides of the accommodation hole, and are biased so as to be close to the second side surface in the circumferential direction.