Multi-Piece Rotor Magnet Easy-Axis Layout Against Demagnetization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing permanent magnets in electric machines are susceptible to demagnetization, particularly at edges and corners, leading to reduced performance due to non-parallel alignment of easy axes with the demagnetizing field, and current solutions to enhance resistance often increase costs.
Innovation Solution
The use of multiple-piece permanent magnets with anisotropic magnetic material, where central and corner pieces have magnetically easy crystallographic axes oriented in different directions to align with the demagnetizing field, reducing demagnetization risk and eddy-current loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing permanent magnets are used with uniform easy axis orientation, then manufacturing is simple and cost-effective, but demagnetization resistance is poor at edges and corners
Solution Approach 1:
The permanent magnet is divided into multiple segments: a central portion with a first easy axis orientation and corner portions with a second easy axis orientation. This segmentation allows each portion to be optimized for its specific location, with corner portions better resistant to demagnetization while the central portion maintains standard orientation, thus improving overall reliability without excessive complexity.
Solution Approach 2:
Different portions of the magnet are given different magnetic properties - the central portion has one easy axis orientation optimized for general performance, while corner portions have a different easy axis orientation specifically optimized to resist demagnetization at high-stress locations. This local differentiation resolves the contradiction by applying complexity only where needed.
2Reliability
If corner portions are added with different easy axis orientation, then demagnetization resistance improves, but manufacturing complexity increases
Solution Approach 1:
The magnet is segmented into central and corner portions that can be manufactured separately and then assembled. This allows each segment to be optimized for its function while simplifying the manufacturing process, as corner portions with specialized orientations can be produced independently and attached to the central portion, rather than requiring complex monolithic manufacturing.
Solution Approach 2:
A bonding agent or intermediary material is used to join the corner portions to the central portion. This intermediary enables the assembly of multi-orientation magnet segments, making the manufacturing process feasible by providing a simple joining mechanism that connects differently oriented magnetic components.
3Reliability
If multi-piece magnet construction is used, then demagnetization resistance improves, but device complexity increases
Solution Approach 1:
The magnet is divided into discrete segments (central portion and corner portions) that can be independently manufactured and then assembled. This segmentation improves demagnetization resistance by allowing optimal orientation at each location while managing complexity through modular assembly rather than monolithic design.
Solution Approach 2:
Multiple magnet portions with different orientations are combined into a single functional magnet assembly. The central portion and corner portions work together as an integrated unit, merging their different magnetic properties to achieve superior overall performance while maintaining manageable assembly complexity through standardized interfaces.
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 enhances resistance to demagnetization while maintaining cost-effectiveness by optimizing the alignment of easy axes with the demagnetizing field, thereby improving the performance and durability of electric machine magnets.
Implementation Method 1
The magnet includes a central piece of anisotropic magnetic material having a first magnetically easy crystallographic axis, and a corner piece of anisotropic magnetic material joined to the central piece and having a second magnetically easy crystallographic axis that is oblique to the first easy axis
Implementation Method 2
This configuration enhances resistance to demagnetization while maintaining cost-effectiveness by optimizing the alignment of easy axes with the demagnetizing field
Data Source
AI summary
A rotor of an electric machine includes a rotor core defining a magnet channel extending axially between opposing ends of the rotor core. A permanent magnet is disposed in the channel and has opposing ends and opposing major sides. The magnet includes a central piece of anisotropic magnetic material having a first magnetically easy crystallographic axis, and a corner piece of anisotropic magnetic material joined to the central piece and having a second magnetically easy crystallographic axis that is oblique to the first easy axis.