Composite Magnetic Sheet for Thin Coil Components
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Solution Overview
Problem
Conventional methods for producing magnetic components, such as ferrite sintered bodies and metal dust cores, face challenges in maintaining strength and magnetic properties when reduced in size or thickness, leading to impracticality for low-height coil components and high production costs.
Innovation Solution
A composite magnetic sheet comprising a resin and metal magnetic powder with a specific aspect ratio and diameter range, aligned parallel to the sheet surface, is produced using a slurry application method, enhancing magnetic properties and strength while simplifying the production process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If ferrite sintered body is reduced in size and thickness, then the coil component achieves lower height and smaller size, but the strength of the ferrite sintered body remarkably decreases
Solution Approach 1:
The invention uses a composite structure consisting of metal magnetic powder particles embedded in a resin matrix. This composite material combines the high magnetic permeability of metal powder with the mechanical strength and flexibility of resin, enabling the magnetic member to maintain adequate strength even when reduced to thin dimensions (0.01-0.25mm), thus resolving the contradiction between reduced thickness and maintained strength.
2Volume of moving object
If ferrite sintered body is reduced in volume or cross sectional area, then the coil component achieves smaller size, but the magnetic properties of the ferrite sintered body tend to decrease
Solution Approach 1:
The invention changes the material parameters by using metal magnetic powder with specific characteristics (particle diameter 5-80μm, aspect ratio 5-20) embedded in resin, rather than relying on sintered ferrite. This parameter change allows maintaining high magnetic properties (permeability μ≥10) even in reduced volumes, as the metal powder-resin composite provides superior magnetic performance at small scales compared to traditional ferrite sintering.
3Length of stationary object
If magnetic green sheets are laminated and pressed to produce low-height coil component, then the coil component achieves lower height, but the production process becomes complicated and production cost increases
Solution Approach 1:
The invention segments the magnetic member into discrete metal magnetic powder particles (5-80μm diameter) suspended in resin, rather than using layered green sheet structures. This segmentation allows the magnetic material to be applied as a simple coating or slurry that can be formed into thin layers (0.01-0.25mm) in a single step, eliminating the need for multiple lamination and pressing operations required by green sheet methods.
4Volume of moving object
If metal dust core is reduced in size and height, then the coil component achieves smaller dimensions, but the strength of the metal dust core decreases
Solution Approach 1:
The invention employs a composite material system where metal magnetic powder particles are embedded in a resin matrix. The resin provides mechanical strength and structural integrity to the metal powder assembly, enabling the magnetic member to maintain adequate strength at reduced sizes (thickness 0.01-0.25mm). This composite approach resolves the strength degradation issue that occurs when metal dust cores are reduced in dimension.
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 composite magnetic sheet achieves improved magnetic properties and strength, enabling its use in thin coil components with reduced thickness, while simplifying production and lowering costs by eliminating the need for magnetic field orientation and complex processes.
Implementation Method 1
the metal magnetic powder is dispersed so that the major axis is aligned in parallel along a surface of the composite magnetic sheet
Data Source
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AI summary
Provided are composite magnetic sheet which has excellent magnetic properties while high strength and thickness reduction are realized and a method of producing the composite magnetic sheet. The composite magnetic sheet 1 includes at least a resin 20 and a metal magnetic powder 10. The metal magnetic powder 10 contains flat powder having a major axis and a minor axis, the flat powder having a diameter of the major axis in the range of not less than 5 µm and not more than 80 µm and having an aspect ratio defined by a dimension ratio between the major axis and the minor axis in the range of not less than 5 and not more than 20. In the composite magnetic sheet 1, the metal magnetic powder 10 is dispersed so that the major axis is aligned parallel along the surface of the composite magnetic sheet 1.