Anisotropic Bonded Magnet Stacking for Axial Density Uniformity
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Solution Overview
Problem
The existing methods for preparing anisotropic bonded magnets with high aspect ratios face challenges in achieving uniform magnetic field orientation and density along the height direction, leading to non-uniform magnetic properties and dimensional accuracy issues.
Innovation Solution
The method involves stacking preforms with varying SmFeN powder content and density, where the middle preforms have a higher SmFeN content and the ends/preiphery have a lower content, to compensate for density deviations during the pressing process, ensuring uniformity and improving magnetic properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If compression molding is used to prepare anisotropic bonded magnets with high aspect ratio, then the magnetic property is improved, but the density uniformity along the height direction deteriorates
Solution Approach 1:
The patent applies local quality by creating preforms with different SmFeN powder contents tailored to specific positions. Middle preforms contain higher SmFeN content (3-40 wt%) while end preforms contain lower SmFeN content, matching the local density requirements of different regions in the final magnet assembly to achieve overall density uniformity within 2% deviation
Solution Approach 2:
The patent segments the magnet into multiple preforms stacked along the height direction. Each preform is independently prepared with specific SmFeN content and density characteristics, allowing localized optimization of material composition to compensate for pressing-induced density variations in different regions
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 results in anisotropic bonded magnets with a density deviation of less than 2% in the pressing direction, enhancing the orientation, density uniformity, and dimensional accuracy of the magnets.
Implementation Method 1
acquisition of a composite magnetic powder by mixing a magnetic powder with a binder and an additive
Implementation Method 2
the binder is softened and melted to be viscous due to high temperature, has certain lubrication effect due to its low viscosity
Implementation Method 3
the binder is softened and melted to be viscous due to high temperature, has certain lubrication effect due to its low viscosity
Implementation Method 4
orienting and pressing... orientation forming process
Implementation Method 5
The additive refers to a lubricant, a coupling agent or the like; and the binder generally is a thermosetting resin such as an epoxy resin, a phenol resin, etc.
Implementation Method 6
demagnetization→curing→anti-corrosion treatment→property detection
Data Source
AI summary
An anisotropic bonded magnet and a preparation method thereof are provided. Through a method of stacking magnets which are different in content of SmFeN and/or have different densities, the magnets in the middle have high properties and the magnets at two ends and/or the periphery have low properties, thereby compensating for a property deviation caused by a difference in densities during a pressing process, and improving the property uniformity of the magnets in an axial direction. The method avoids the phenomenon of non-uniform magnetic field orientation and density in a height direction during orientation and densification as well as the phenomenon of low in the middle and high at two ends.