Rotor Lamination Tabs for Secure Magnet Retention
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Solution Overview
Problem
Existing rotor assemblies for electric motors face challenges in securely retaining magnets within cavities during assembly and operation, as conventional methods like mandrels can lead to magnets falling out due to slip fits, and additional fastening mechanisms may be required to prevent this issue.
Innovation Solution
The rotor assembly employs a lamination stack with notch and tab laminations, where flexible tabs from tab laminations bend into notches of notch laminations to create cavities that securely hold magnets in place, providing a press fit and biasing force without the need for additional fastening mechanisms, allowing for controlled support and retention of magnets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mandrels are used to retain magnets during assembly, then magnets can be held in place temporarily, but magnets may fall out due to slip fits and additional fastening mechanisms are required
Solution Approach 1:
The flexible tabs on the laminations self-adjust to retain the magnets through elastic deformation. The tabs bend elastically under the weight of the magnets and maintain continuous contact pressure, providing automatic retention without external fastening mechanisms. This eliminates the need for additional retention components while ensuring reliable magnet positioning throughout assembly and operation.
2Reliability
If additional fastening mechanisms are added to secure magnets, then magnet retention is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The magnet retention function is merged into the lamination structure itself through the flexible tabs. The tabs are integrally formed with the laminations and perform dual functions: providing structural support for the rotor core and simultaneously securing the magnets through elastic deformation. This integration eliminates separate fastening mechanisms and simplifies the manufacturing process.
3Strength
If rigid structures are used to hold magnets, then structural strength is improved, but flexibility and adaptability in magnet support are reduced
Solution Approach 1:
The lamination structure transitions from a rigid configuration to a dynamic one through the flexible tabs. The tabs are designed with appropriate flexibility to bend elastically under magnetic weight and assembly forces, allowing the structure to adapt to manufacturing tolerances and operational conditions. This dynamic behavior maintains structural integrity while providing necessary flexibility for reliable magnet retention.
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 solution effectively secures magnets within the rotor assembly, preventing them from falling out during assembly and operation, while allowing for adjustable support based on manufacturing methods and performance objectives, enhancing the reliability and efficiency of the rotor assembly.
Implementation Method 1
The flexible tabs of the at least one tab lamination bends toward the notches of the set of notch laminations by a magnet from among the plurality of magnets
Data Source
AI summary
A rotor assembly includes a rotor core that defines a plurality of cavities and includes a plurality of laminations having annular bodies and stackably arranged to form the rotor core. The plurality of laminations includes a plurality of notch laminations and at least one tab lamination. Each notch lamination defines a plurality of first apertures. Each first aperture has a notch at a portion of the first aperture. The tab lamination defines a plurality of second apertures and includes flexible tabs extending toward the second apertures. The plurality of first apertures and the plurality of second apertures define at least a portion of the plurality of the cavities. A set of notch laminations are stacked with the tab lamination, where the notches of the set of notch laminations align with the flexible tabs of the tab lamination.