Rotor Magnet Extraction by Thermal Softening for Motor Recycling
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Solution Overview
Problem
Current methods for recycling permanent magnets from synchronous reluctance motors often require shredding the motor, which is inefficient and results in additional processing steps to separate hard magnetic materials from soft magnetic materials, making it difficult to repurpose the magnets effectively.
Innovation Solution
A method and system that heat the rotor to a specific temperature to soften the adhesive or polymer bonding, allowing for the mechanical removal of permanent magnets from their cavities without shredding, and then process them for reuse in a new rotor, reducing the number of processing steps required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the motor is shredded to recycle permanent magnets, then the magnets can be recovered, but additional processing steps are required to separate hard magnetic materials from soft magnetic materials
Solution Approach 1:
The patent extracts the permanent magnets from the rotor assembly before recycling by heating the rotor to a temperature above the glass transition temperature of the polymer material, causing the polymer to soften and allowing the magnets to be removed intact from their cavities. This extraction approach avoids shredding and eliminates the need for complex separation processes to distinguish between hard and soft magnetic materials.
Solution Approach 2:
The patent changes the temperature parameter of the rotor to above the glass transition temperature of the polymer material, which alters the physical state of the polymer from rigid to softened. This parameter change enables the permanent magnets to be easily removed from the rotor cavities without damaging the magnets or requiring additional separation steps.
2Loss of substance
If the motor is shredded to recycle permanent magnets, then the magnets can be recovered, but the magnets require additional processing to be suitable for reuse
Solution Approach 1:
By extracting the permanent magnets intact from the rotor cavities through thermal softening of the polymer material, the magnets are recovered in a condition that is directly suitable for reuse. This extraction method preserves the magnets' structural integrity and magnetic properties, eliminating the need for additional processing steps such as separation from soft magnetic materials that would be required if shredding were used.
Solution Approach 2:
The patent performs preliminary action by heating the rotor to soften the polymer material before magnet removal. This preliminary thermal treatment prepares the rotor structure to allow clean extraction of magnets in their original form, ensuring they are ready for direct reuse without requiring subsequent processing to restore their suitability for installation in new motors.
3Productivity
If the rotor is heated to remove permanent magnets, then the magnets can be separated without shredding, but energy is consumed for heating
Solution Approach 1:
The patent changes the temperature parameter of the rotor to above the glass transition temperature of the polymer material, which fundamentally alters the polymer's physical properties from rigid to softened. This parameter change enables efficient magnet extraction without shredding, and the energy required is optimized by targeting a specific temperature threshold rather than excessive heating.
Solution Approach 2:
The patent utilizes the phase transition of the polymer material at its glass transition temperature, where the material transitions from a rigid glassy state to a softened rubbery state. This phase transition occurs at a specific temperature threshold, allowing for efficient energy use - heating only to the point where the polymer softens sufficiently to enable magnet removal, without requiring continuous or excessive energy input.
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 the efficient separation and reuse of permanent magnets by avoiding the shredding process, preserving the magnets' integrity and reducing the need for additional processing, thus facilitating their direct installation into new AC motors.
Implementation Method 1
heating the first rotor to a first temperature
Implementation Method 2
the first temperature is greater than a glass transition temperature of the polymer material
Implementation Method 3
removing one or more permanent magnets from a respective cavity of the plurality of cavities by applying a force onto the one or more permanent magnets
Implementation Method 4
heating the one or more permanent magnets to a second temperature, and the second temperature is greater than the first temperature
Implementation Method 5
separating the polymer material from a magnetic material of the one or more permanent magnets
Data Source
AI summary
A system and method for separating permanent magnets from a rotor for repurposing. The method includes obtaining a first rotor including a plurality of permanent magnets located in a plurality of cavities arranged in the first rotor, heating the first rotor to a first temperature, removing the permanent magnets from a respective cavity by applying a force onto the permanent magnets at the first temperature, and repurposing the permanent magnets for a secondary use. The first temperature may be greater than a glass transition temperature and less than a melting temperature. The permanent magnets may be further processed for installation into a second rotor, the processing may include grinding the one or more permanent magnets to enable installation into the second rotor, analyzing a structural integrity of the permanent magnets to determine suitability for repurposing, and may also include separating the polymer material from a magnetic material.