Permanent Magnet Rotor Adhesive Layout for Higher Electromagnetic Torque
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Solution Overview
Problem
The presence of a continuous glue layer between permanent magnets and the rotor in existing electric motors hinders the propagation of the magnetic field, resulting in poorer electromagnetic torque and less efficient motor operation.
Innovation Solution
A rotor design with a bell-shaped annular wall where permanent magnets are fixed using adhesive means in a localized fixing zone, allowing direct contact between the magnet and the rotor without intermediate adhesive, and using a magnetic material for the bell to enhance magnetic flux passage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a continuous layer of adhesive is applied around the entire circumference of the annular wall to fix permanent magnets, then the mounting speed and positioning flexibility are improved, but the magnetic field propagation is hindered and electromagnetic torque is reduced
Solution Approach 1:
The continuous adhesive layer is segmented into discrete adhesive deposits positioned at specific locations between the permanent magnets. This segmentation allows magnetic flux to propagate through the annular wall in regions where no adhesive is present, while still providing sufficient mechanical fixation at the adhesive deposit locations.
Solution Approach 2:
The adhesive application transitions from a uniform continuous layer to a non-uniform distributed pattern with varying local densities. Adhesive is concentrated at specific locations between magnets where fixation is most needed, while leaving gaps in other regions to permit magnetic field propagation.
2Adaptability or versatility
If a continuous layer of adhesive is applied around the entire circumference of the annular wall, then the positioning flexibility of permanent magnets is improved, but the amount of adhesive used increases
Solution Approach 1:
The adhesive layer is segmented into discrete deposits placed only where mechanically necessary for magnet fixation. This eliminates adhesive application in regions where magnets are already securely positioned or where magnetic field propagation is prioritized, reducing total adhesive consumption.
Solution Approach 2:
The invention discards the conventional approach of applying adhesive uniformly everywhere, and instead recovers adhesive by applying it only in strategically selected locations between magnets, thereby reducing material waste while maintaining fixation effectiveness.
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 design achieves a higher quality electromagnetic torque and reduces adhesive usage, leading to more efficient motor operation and cost savings by minimizing the adhesive quantity.
Implementation Method 1
The switching of current in the stator coils generates a rotating magnetic field toward which the permanent magnets on the rotor aim to align themselves
Implementation Method 2
The presence of this glue layer hinders the propagation of the magnetic field generated by the interaction of each magnet with the energized coils within the rotor
Implementation Method 3
at least one permanent magnet fixed to the annular wall by means of adhesive means disposed between the annular wall and a rear face of the permanent magnet
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
A permanent magnet rotor (100) for an electric motor comprises a cover (110) including an annular wall (112) and at least one permanent magnet (120) that is attached to the annular wall by adhesive means (126) that are arranged between a rear face (124) and the annular wall (112). The rear face (124) of the permanent magnet (120) has an area (134) for receiving said adhesive means (126) that is defined by a radius of curvature (R', R2) that is greater than the radius of curvature (R) of the annular wall (112).