Soft Magnetic Material Core with Bimodal Particle Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional soft magnetic materials struggle to maintain high permeability and DC superimposition characteristics when inductors are downsized, leading to decreased inductance and deteriorated DC superimposition characteristics due to insufficient filling rates of soft magnetic particles.
Innovation Solution
A soft magnetic material comprising two particle groups, α and β, with specific size and intensity ratios, where the larger particles of group α efficiently accommodate smaller particles of group β, increasing the filling rate and enhancing permeability and DC superimposition characteristics, using Fe-based powders coated with insulation materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the inductor is downsized to achieve smaller size, then the device size is reduced, but the core volume decreases leading to decreased inductance and deteriorated DC superimposition characteristic
Solution Approach 1:
The soft magnetic metal powder is divided into two distinct particle groups (α and β) with different particle sizes. The larger α particles (20-50 μm) provide structural framework while the smaller β particles (1-10 μm) fill the interstices, creating a segmented size distribution that maximizes filling density in compact volumes while maintaining magnetic performance
Solution Approach 2:
The smaller β particles are nested within the spaces formed by the larger α particles. This nested arrangement allows small particles to occupy the voids between large particles, achieving high filling rates (75-85 vol%) in downsized cores without compromising the magnetic pathway continuity needed for good DC superimposition characteristic
2Quantity of substance
If the ratio of fine powder (particle size 1-10 μm) is increased to improve filling rate, then the filling rate increases slightly, but the permeability and DC superimposition characteristic are still insufficient
Solution Approach 1:
The invention optimizes two critical parameters: the volume ratio Vα/Vβ between particle groups is controlled at 2.0-5.1, and the intensity ratio IC/IA is kept at 0.12 or less. These parameter combinations create an optimal size distribution where small particles efficiently fill spaces without creating excessive interfacial resistance, achieving both high filling rate (75-85 vol%) and high permeability (≥30)
Solution Approach 2:
The soft magnetic material forms a composite structure combining two different particle size groups with complementary functions. The α particles (20-50 μm) provide magnetic pathway continuity and structural integrity, while β particles (1-10 μm) maximize space utilization. This composite particle size distribution achieves synergistic effects that neither particle group could achieve alone, resulting in high permeability and excellent DC superimposition characteristic
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 achieves high permeability and excellent DC superimposition characteristics, enabling effective performance in compact inductor designs by optimizing the size distribution and filling rate of soft magnetic particles, thereby improving inductance and reducing the inductance decreasing rate under DC bias.
Implementation Method 1
the soft magnetic metal powder is coated with an insulation material
Implementation Method 2
the soft magnetic metal powder constituting said particle group α is Fe or a metal comprising Fe
Data Source
AI summary
The object of the present invention is to provide the soft magnetic material, the core, and the inductor having high permeability and excellent DC superimposition characteristic.A soft magnetic material comprising a soft magnetic metal powder and a resin, wherein said soft magnetic metal powder is constituted from a particle group α and a particle group β, when IA is a peak intensity of the particle group α, Vα is the volume of the particle group α, IB is a peak intensity of the particle group β, Vβ is the volume of the particle group β, and IC is a minimum intensity present between the particle group α and the particle group β, then an intensity ratio IC/IA satisfies 0.12 or less, and a volume ratio Vα/Vβ is 2.0 or more and 5.1 or less.