Co-Fired Inductor Structure for High Saturation Current Density
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Solution Overview
Problem
Traditional high-current inductors are large due to the need for air gaps to increase saturation current capacity, which also introduces assembly challenges and reduces product yield, and existing integrated inductor manufacturing methods often result in additional air gaps and insufficient molding precision.
Innovation Solution
An integrated co-fired inductor is manufactured using a method that involves filling a mold cavity with magnetic powder, embedding wires, and performing compression molding followed by heat treatment to reduce stress and hysteresis losses, eliminating extra gaps between the wire and magnetic core and uniformly distributing air gaps within the core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If air gap is opened to increase saturation current capacity, then saturation current capacity is improved, but device size increases and manufacturing complexity increases
Solution Approach 1:
The patent combines the magnetic core and coil into a single integrated component manufactured through co-firing, eliminating the need for separate air gap structures and multiple assembly steps. The magnetic powder core is formed with built-in flux paths that provide saturation current capacity without requiring external air gaps, thus reducing device size while maintaining reliability.
Solution Approach 2:
The patent uses magnetic powder core material with controlled porosity and permeability characteristics. The magnetic powder structure provides inherent magnetic flux distribution that achieves high saturation current capacity through material properties rather than geometric air gaps, thereby reducing overall device volume.
2Reliability
If air gap is opened to increase saturation current capacity, then saturation current capacity is improved, but manufacturing precision deteriorates due to assembly requirements
Solution Approach 1:
The patent integrates the magnetic core and coil into a single co-fired component, eliminating multiple assembly operations and associated tolerance accumulation. The co-firing process creates a monolithic structure where the magnetic core and coil are permanently bonded, removing the need for precision assembly of separate parts with air gaps.
Solution Approach 2:
The patent performs preliminary shaping and positioning of the coil within the magnetic core during the co-firing process itself, rather than requiring post-manufacturing assembly. The green state coil is positioned and fixed before firing, ensuring precise final positioning without requiring tight assembly tolerances.
3Volume of stationary object
If integrated molding is used to reduce device size, then device size is reduced, but additional air gaps are introduced reducing magnetic permeability
Solution Approach 1:
The patent optimizes the magnetic powder properties including particle size distribution, density, and coating characteristics to achieve high magnetic permeability in the integrated structure. By controlling the magnetic powder parameters and co-firing conditions, the patent achieves both compact size and high magnetic permeability without compromising either property.
4Reliability
If traditional assembly method is used to achieve high saturation current, then saturation current capacity is improved, but productivity decreases due to multiple assembly steps
Solution Approach 1:
The patent combines multiple manufacturing operations (coil winding, core formation, assembly, and bonding) into a single co-firing process. The coil is positioned in the green state core, and both components are fired simultaneously to create a permanent bond, eliminating multiple separate assembly steps and significantly improving manufacturing efficiency while maintaining high saturation current capacity.
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 reduces device losses, vibration noise, and manufacturing costs by eliminating the need for multiple component assembly and ensuring precise molding, resulting in a more efficient and reliable inductor with improved magnetic permeability and saturation current capacity.
Implementation Method 1
performing compression molding followed by heat treatment
Implementation Method 2
performing compression molding followed by heat treatment to reduce stress and hysteresis losses
Implementation Method 3
heat treatment to reduce stress and hysteresis losses
Implementation Method 4
integrated co-fired inductor
Data Source
AI summary
An integrated co-fired inductor and preparation method therefor, comprising: filling a mold cavity with a magnetic powder, embedding at least one wire in the magnetic powder, wherein the two ends extend out of the mold cavity, sequentially performing compression molding and heat treatment to obtain a magnetic core, and bending and tinning the wire extending out of the magnetic core to obtain the co-fired inductor. The preparation method uses an integrated mold forming process to prepare the inductor to avoid an assembly process involving an excessive number of components; heat treatment is performed after the integral forming process, stress is fully released, material hysteresis loss is reduced, and the loss of the device under light load conditions is reduced; no extra gap exists between the wire and the magnetic core, air gaps are uniformly distributed within the magnetic core, and the vibration noise of eddy current loss is reduced.