Rotor Permanent Magnet Segmentation for Eddy Current Reduction
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Solution Overview
Problem
Existing methods for manufacturing rotors with permanent magnets face challenges in reducing costs and handling difficulties due to the need for multiple steps and precise handling of small magnet pieces, which can lead to increased eddy current losses and higher manufacturing costs.
Innovation Solution
A method involving dividing a permanent magnet into pieces and resin-molding them within a molding die using the pressure of injected resin to form a magnet assembly, eliminating the need for grinding and additional insulation treatments, and utilizing gates and pins to ensure appropriate positioning and insulation between the magnet pieces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a larger permanent magnet is used to enhance motor output, then motor power is improved, but eddy current losses and heat generation increase
Solution Approach 1:
The permanent magnet is divided into multiple smaller magnet pieces arranged in a matrix pattern. This segmentation reduces the continuous conductive path for eddy currents, thereby minimizing eddy current losses while maintaining the total magnetic strength required for high motor output.
2Loss of energy
If multiple insulation coating steps are applied to permanent magnet pieces, then eddy current prevention is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The insulation coating process is integrated into the resin molding step. The resin serves dual purposes: it acts as the bonding matrix holding the magnet pieces together and simultaneously provides the insulation coating between adjacent magnets. This eliminates separate insulation coating steps while ensuring effective eddy current prevention.
Solution Approach 2:
The resin acts as an intermediary material that performs multiple functions: it bonds the magnet pieces together structurally and provides electrical insulation between them. This single intermediary material replaces what would otherwise require separate insulation layers and coating processes.
3Reliability
If permanent magnet pieces are handled individually through multiple processing steps, then insulation and bonding quality is improved, but handling difficulty and manufacturing time increase
Solution Approach 1:
The magnet pieces are pre-positioned in their final arrangement within the mold cavity before resin injection. This preliminary positioning ensures correct spatial relationships and insulation gaps are established before the bonding process begins, eliminating the need for subsequent adjustment operations and reducing manufacturing time.
Solution Approach 2:
The resin injection process automatically performs multiple functions simultaneously: it fills the gaps between pre-positioned magnet pieces, provides insulation coating, and bonds the assembly together. The process is self-contained within a single operation, eliminating the need for separate handling, insulation, and bonding steps.
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 approach reduces manufacturing costs and lead time by simplifying the handling and insulation of magnet pieces, enhancing insulation properties, and minimizing eddy current losses, while maintaining high motor performance.
Implementation Method 1
moving the permanent magnet pieces within the molding die by moving means for moving the permanent magnet pieces to form the magnet assembly, the moving means being provided by utilizing the pressure of resin to be injected from a gate of the molding die
Implementation Method 2
arranging and resin-molding the permanent magnet pieces to form a magnet assembly with insulation between the permanent magnet pieces
Data Source
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AI summary
A purpose is to provide a rotor manufacturing method including a magnet assembly formed of divided permanent magnet pieces to enhance insulation and advance cost reduction. The rotor manufacturing method includes forming permanent magnet pieces (60) by dividing a permanent magnet (50), arranging and resin-molding the permanent magnet pieces (60) to form a magnet assembly (40), and placing the magnet assembly (40) in a rotor (10). The method includes placing the permanent magnet pieces (60) all together in a molding die (200) for use in resin-molding, and moving the permanent magnet pieces (60) by a moving means provided in the molding die (200) to move the permanent magnet pieces (60) within the molding die (200), thereby forming the magnet assembly.