Permanent Magnet Rotor Deflectable Lamination Tabs
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Solution Overview
Problem
Existing permanent magnet rotors face challenges in securely fastening permanent magnets within magnet pockets, especially under temperature fluctuations, which can cause micro-movements and instability.
Innovation Solution
The use of deflectable sheet metal tongues in the laminated cores, which maintain a frictional connection between the permanent magnets and the magnet pockets by deflecting in opposite axial directions, preventing movement and allowing for a sliding press-in process, along with variations in sheet metal sections and tongue designs to facilitate assembly and adjust press-in force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If permanent magnets are pressed into magnet pockets with high pressing force to prevent migration, then fastening security is improved, but assembly difficulty increases and risk of damage rises
Solution Approach 1:
The pressing force is applied axially rather than radially, changing the direction and distribution of force. This allows the magnets to be pressed in uniformly without concentrated stress points, maintaining secure fastening while reducing assembly difficulty and damage risk
Solution Approach 2:
The rotor is divided into two partial laminated cores with alternating lamination tab configurations. This segmentation allows different regions to handle pressing forces differently, with some tabs providing support and others allowing deflection, thereby securing magnets without requiring excessive pressing force
2Reliability
If lamination tabs are made rigid to prevent magnet movement, then fastening security is improved, but flexibility to accommodate temperature fluctuations decreases
Solution Approach 1:
The lamination tabs are designed with controlled flexibility rather than being completely rigid. They can deflect elastically to accommodate thermal expansion and contraction of the magnets, while still maintaining sufficient friction to prevent migration. This dynamic behavior allows the system to adapt to temperature changes while preserving fastening security
Solution Approach 2:
The mechanical properties of the lamination tabs are optimized to provide the right balance between rigidity and flexibility. By controlling the tab dimensions and material properties, the system maintains adequate friction force while allowing sufficient deflection for thermal compensation
3Reliability
If multiple different sheet metal cuts are used to optimize magnet fastening, then fastening security is improved, but manufacturing complexity increases
Solution Approach 1:
The rotor is divided into two partial laminated cores with alternating tab configurations, allowing the use of two different sheet metal cuts. This segmentation enables optimized fastening in different regions while limiting the number of unique cuts to just two, thereby maintaining manufacturing simplicity
Solution Approach 2:
The two partial laminated cores use asymmetric but complementary tab configurations. This allows each cut to be optimized for its specific position while maintaining overall symmetry in the complete rotor, balancing manufacturing simplicity with fastening effectiveness
4Reliability
If lamination tabs extend far radially to increase gripping force, then fastening security is improved, but flux leakage increases
Solution Approach 1:
The radial extent of the lamination tabs is optimized to provide sufficient gripping force through increased surface area and friction, while staying clear of the main magnetic flux paths. This parameter optimization allows the tabs to extend far enough radially to secure magnets effectively without significantly increasing flux leakage
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 ensures secure fastening of permanent magnets over the service life, withstands temperature-induced movements, and allows for economical production with simplified assembly, while minimizing flux leakage and magnetic short circuits.
Implementation Method 1
maintain a frictional connection between the permanent magnets and the magnet pockets
Implementation Method 2
Deflectionable lamination tabs, which maintain the force-fit between the permanent magnets and the magnet pockets
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a permanent magnet rotor (1) of an electric motor, comprising a laminated core (2) composed of two partial lamination stacks (3, 4), and a plurality of permanent magnets (6) force-fitted into magnetic pockets (5) of the laminated core, the magnets extending over both partial lamination stacks (3, 4). The object of the invention is to ensure, in a permanent magnet rotor of this type, a secure and durable fastening of the permanent magnets in the magnetic pockets, while enabling the simplest possible assembly. This object is achieved according to the invention by the features of claim 1 and the method according to claim 10.