Composite Dust Core for Low Loss and High Density
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Solution Overview
Problem
Existing dust cores made from pulverized Fe-based amorphous alloy ribbons suffer from high core loss and inadequate DC superposed characteristics, despite efforts to improve compaction density and magnetic properties.
Innovation Solution
A dust core is fabricated using a combination of pulverized Fe-based amorphous alloy ribbon powder in the form of thin plates with specific grain size distribution and Cr-containing Fe-based amorphous alloy atomized spherical powder, with a controlled mixing ratio and coated with epoxy resin and silicone rubber, to achieve low core loss and high density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If pulverized Fe-based amorphous alloy ribbon is used as core material, then core loss is reduced, but DC superposed characteristics deteriorate
Solution Approach 1:
The invention uses a composite dust core made by mixing pulverized Fe-based amorphous alloy ribbon (maintaining thin plate shape with specific grain size distribution) with spherical Fe-based amorphous alloy powder. This composite structure combines the low core loss advantage of pulverized ribbon with the good DC superposed characteristics of spherical powder, achieving both objectives simultaneously.
Solution Approach 2:
The invention applies local quality by controlling the grain size distribution of the pulverized ribbon powder specifically (minimum dimension along plane direction: more than twice and not more than six times the thickness), while mixing with spherical powder of different size characteristics. This localized optimization of particle morphology in different regions of the composite material resolves the contradiction between core loss and DC characteristics.
2Loss of energy
If pulverized Fe-based amorphous alloy ribbon is used, then core loss is reduced, but molded body density and strength are insufficient
Solution Approach 1:
The invention creates a composite dust core combining pulverized ribbon powder with spherical Fe-based amorphous alloy powder. The spherical powder acts as a filler that improves the packing density and mechanical strength of the molded body, while the pulverized ribbon powder maintains the low core loss characteristic. This composite approach simultaneously addresses both requirements.
Solution Approach 2:
The invention changes the physical and chemical parameters of the core material by controlling the grain size distribution of the pulverized ribbon (minimum dimension: 2-6 times the thickness) and mixing ratio with spherical powder. These parameter optimizations enable the molded body to achieve both low core loss and high density/strength.
3Ease of manufacture
If spherical powder and flake powder have substantially the same diameter, then compaction is easy, but compaction density is minimally improved
Solution Approach 1:
The invention uses a composite of pulverized ribbon powder (thin plate shape with controlled grain size) and spherical powder (different size characteristics). The size difference between the two powder types creates complementary packing, where smaller particles fill voids between larger particles, significantly improving compaction density while maintaining ease of manufacture.
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
The solution results in a dust core with significantly reduced core loss, improved DC superposed characteristics, and enhanced mechanical strength, while maintaining satisfactory magnetic properties, effectively addressing the limitations of previous technologies.
Implementation Method 1
a Cr-containing Fe-based amorphous atomized spherical powder with a grain size not more than a half of the thickness of the pulverized powder and not less than 3 μm is mixed with the pulverized powder for attaining a high density of a molded body
Implementation Method 2
coated with epoxy resin and silicone rubber, to achieve low core loss and high density
Data Source
AI summary
The present invention provides a dust core including, as principal components, a pulverized powder of an Fe-based amorphous alloy ribbon; and a Cr-containing Fe-based amorphous alloy atomized spherical powder, and the pulverized powder is in the shape of a thin plate having two principal planes opposing each other, and assuming that a minimum dimension along a plane direction of the principal planes is a grain size, the pulverized powder includes a pulverized powder with a grain size more than twice and not more than six times as large as a thickness of the pulverized powder in a proportion of 80 mass % or more of the whole pulverized powder and includes a pulverized powder with a grain size not more than twice as large as the thickness of the pulverized powder in a portion of 20 mass % or less of the whole pulverized powder.