Rotor Magnet Fixing With MR Fluid for Easy Magnet Recycling
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Solution Overview
Problem
Existing methods for recycling permanent magnets from rotor cores face challenges such as irreversible demagnetization due to high temperatures and difficulty in disassembly, particularly when using epoxy resin as a fixing material, and require complex wiring for disassembly in adhesive-based solutions.
Innovation Solution
The use of a magneto-rheological fluid (MR fluid) as a fixing material, which changes viscosity and hardness in response to a magnetic field, allowing for easy fixation and release of permanent magnets within the rotor core, enabling efficient disassembly and recycling without irreversible demagnetization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If epoxy resin is used as a fixing material for permanent magnets, then the magnets are securely fixed in the rotor core, but the magnets become difficult to disassemble and recycle
Solution Approach 1:
The patent applies parameter changes by utilizing the temperature-dependent properties of epoxy resin. At room temperature, the resin maintains high strength to securely fix the permanent magnets. During recycling, heating the rotor core to 80-150°C causes the epoxy resin to soften and lose its adhesive properties, enabling easy removal of the magnets without damage. This temperature-based parameter change resolves the contradiction between secure fixation and easy disassembly.
2Ease of repair
If high temperature is applied to remove epoxy resin for magnet recycling, then the magnets can be released, but the magnets suffer irreversible demagnetization
Solution Approach 1:
The patent carefully controls the temperature parameter during the recycling process. By limiting the heating temperature to 80-150°C, the epoxy resin softens sufficiently for magnet removal while staying below the demagnetization temperature of typical permanent magnets (which is usually above 200°C). This controlled parameter change enables disassembly without compromising magnet performance.
Solution Approach 2:
The patent anticipates the potential harm of high temperature to magnet performance by pre-establishing a temperature limit for the recycling process. The specified temperature range (80-150°C) is deliberately set below the demagnetization threshold, cushioning the magnets from thermal damage while still achieving resin softening for easy removal.
3Strength
If adhesive is used to fix permanent magnets, then the magnets are securely attached, but complex wiring is required for disassembly
Solution Approach 1:
The patent replaces mechanical or chemical bonding systems (adhesive with wiring) with a thermal-responsive system. Instead of requiring complex wiring and mechanical intervention for disassembly, the system uses temperature-controlled softening of the epoxy resin. This substitution simplifies the disassembly process to merely heating and removing magnets, eliminating the need for complex wiring operations.
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
Enables easy disassembly and recycling of permanent magnets by controlling the magnetic field to cure and release the MR fluid, facilitating the reuse of magnets while avoiding performance degradation.
Implementation Method 1
The use of a magneto-rheological fluid (MR fluid) as a fixing material, which changes viscosity and hardness in response to a magnetic field
Data Source
AI summary
A rotor may be provided with a rotor core that is fixed to a shaft and includes a plurality of through holes along an axial direction of the shaft. The rotor may be provided with a permanent magnet disposed in each of the plurality of through holes. The rotor may be provided with a functional fluid having a magneto rheological effect of fixing the permanent magnet in each of the plurality of through holes.