Rotor Lamination Magnet Pocket Stop Elements
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Solution Overview
Problem
Magnet movement due to dimensional deviations in rotor laminations causes noise and asymmetries in the magnetic circuit, and existing designs weaken the magnetic flux, leading to inefficiencies in electric motors.
Innovation Solution
Incorporating stop elements on the sides of magnet pockets to ensure precise magnet positioning and recesses that increase the transverse extent of magnet pockets, minimizing material in areas where magnets adjoin to prevent short-circuit currents, with triangular recesses and rounded tips to enhance magnetic flux homogeneity and ease of manufacture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnet pockets are designed with larger transverse extent to accommodate dimensional deviations, then magnet positioning stability is improved, but magnetic flux is weakened due to increased material removal
Solution Approach 1:
The magnet pocket is segmented into multiple functional zones: a base pocket for magnet accommodation, stop elements for positioning, and recesses for flux management. This segmentation allows each zone to perform its specific function optimally without compromising the others.
Solution Approach 2:
Different regions of the magnet pocket have different properties: the stop elements provide mechanical constraint with minimal material removal, while the recesses are strategically positioned to preserve magnetic flux paths. This local differentiation resolves the contradiction between positioning stability and flux maintenance.
2Manufacturing precision
If material is removed to create recesses that prevent short-circuit currents, then magnetic flux homogeneity is improved, but structural strength is reduced
Solution Approach 1:
The recesses are designed with rounded tips rather than sharp corners. This curvature reduces stress concentration points that would otherwise weaken the rotor lamination, while still maintaining the flux-homogenizing function of the recesses.
Solution Approach 2:
The recesses are designed to extend partially into the magnet pocket rather than completely through it. This partial action is sufficient to prevent short-circuit currents and improve flux homogeneity while minimizing material removal and preserving structural strength.
3Reliability
If stop elements are positioned close to magnets for precise positioning, then magnet stability is improved, but manufacturing tolerance requirements increase
Solution Approach 1:
The stop elements are pre-positioned on the rotor lamination during manufacturing, establishing a fixed reference framework before magnets are installed. This preliminary action allows magnets to be positioned accurately without requiring extremely tight tolerances on the stop elements themselves.
Solution Approach 2:
The magnets themselves serve as the positioning reference for the stop elements during assembly. The stop elements are designed to contact the magnets and use their dimensions as the primary tolerance reference, rather than requiring independent high-precision positioning of the stop elements.
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a rotor lamination (7) for a rotor (3) of an electric motor (1), with at least two magnet pockets (9) for receiving a magnet (10). The magnet pockets (9) each have a transverse dimension (x) extending substantially perpendicular to an axis of symmetry (11) of the rotor lamination (7) and a vertical dimension (y) extending in the direction of the axis of symmetry (11). The magnet pockets (9) each have recesses (12) on both sides that enlarge their transverse dimension (x) and stop elements (13) projecting into the recesses (12) to provide abutment for the magnet (10) on both sides. The stop elements (13) are arranged on the sides of the recesses (12) facing the outer circumference of the rotor lamination (7). The magnetic pockets (9) have recesses (14) on their sides facing away from the outer circumference of the rotor plate (7), adjoining the recesses (12) and increasing the area of the magnetic pockets (9).