Magnetic Gap Coil Component for High Inductance Under DC Bias
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Solution Overview
Problem
Conventional coil components with metal magnetic particles of different relative permeabilities face challenges in achieving high magnetic permeability and DC superposition characteristics due to magnetic saturation and low filling factor, which are exacerbated by high or low molding pressures.
Innovation Solution
A coil component design with a magnetic base body containing first and second metal magnetic particles of varying elastic limits and relative permeabilities, accompanied by magnetic gap portions that enhance the magnetic flux distribution, is molded using a pressure below the elastic limit of the first particles but above the second, followed by heat treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high molding pressure is used to increase filling density and achieve high magnetic permeability, then magnetic permeability is improved, but magnetic saturation occurs sequentially in different magnetic paths causing poor DC superposition characteristics
Solution Approach 1:
The patent introduces magnetic gap portions at specific locations (interfaces between first and second metal magnetic particles) rather than uniformly throughout the magnetic base body. This local modification creates preferential magnetic flux paths that distribute magnetic flux more evenly across different magnetic paths, preventing sequential magnetic saturation and improving DC superposition characteristics while maintaining high magnetic permeability.
Solution Approach 2:
The magnetic gap portions act as intermediary elements between the high permeability first metal magnetic particles and the second metal magnetic particles. These gap portions modify the magnetic flux distribution by creating controlled magnetic reluctance zones that prevent magnetic flux concentration in specific paths, thereby preventing magnetic saturation and improving DC superposition characteristics.
2Reliability
If low molding pressure is used to avoid plastic deformation, then magnetic saturation is reduced, but filling factor decreases making it difficult to achieve high inductance
Solution Approach 1:
The patent changes the physical state of the metal magnetic particles by controlling the molding pressure to be below the elastic limit, preventing plastic deformation. Additionally, magnetic gap portions are introduced to modify the magnetic flux distribution, enabling the system to achieve both low deformation (maintaining particle integrity) and high inductance (through improved magnetic flux paths) simultaneously.
3Productivity
If high molding pressure is used to achieve high filling factor, then inductance is improved, but adjacent metal magnetic particles are tightly adhered causing sequential magnetic saturation
Solution Approach 1:
The patent introduces magnetic gap portions at specific locations (interfaces between first and second metal magnetic particles) rather than uniformly throughout the magnetic base body. This local modification creates preferential magnetic flux paths that distribute magnetic flux more evenly across different magnetic paths, preventing sequential magnetic saturation and improving DC superposition characteristics while maintaining high magnetic permeability.
Solution Approach 2:
The magnetic gap portions act as intermediary elements between the high permeability first metal magnetic particles and the second metal magnetic particles. These gap portions modify the magnetic flux distribution by creating controlled magnetic reluctance zones that prevent magnetic flux concentration in specific paths, thereby preventing magnetic saturation and improving DC superposition characteristics.
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 design improves DC superposition characteristics by inhibiting magnetic saturation and maintaining high permeability, thus achieving both high inductance and efficient magnetic flux distribution.
Implementation Method 1
as the direct current running through the coil conductor increases, magnetic saturation occurs sequentially from a magnetic path with a higher proportion of the high permeability particles
Implementation Method 2
each of the first metal magnetic particles having a first elastic limit and a first relative permeability, each of the second metal magnetic particles having a second elastic limit smaller than the first elastic limit and a second relative permeability lower than the first relative permeability
Implementation Method 3
each of the first metal magnetic particles having a first elastic limit and a first relative permeability, each of the second metal magnetic particles having a second elastic limit smaller than the first elastic limit
Implementation Method 4
Such high molding pressures cause plastic deformation of the metal magnetic particles and, in the pressure-formed magnetic base body, adjacent metal magnetic particles are tightly adhered to one another
Implementation Method 5
followed by heat treatment
Data Source
AI summary
A coil component according to one aspect of the present invention includes: a coil conductor extending around a coil axis; and a magnetic base body intersecting the coil axis. The magnetic base body includes first metal magnetic particles, second metal magnetic particles, and magnetic gap portions, each of the first metal magnetic particles having a first elastic limit and a first relative permeability, each of the second metal magnetic particles having a second elastic limit smaller than the first elastic limit and a second relative permeability lower than the first relative permeability, each of the magnetic gap portions covering a surface of associated one of the first metal magnetic particles and configured such that a first thickness of the magnetic gap portion in a first direction along the coil axis is larger than a second thickness of the magnetic gap portion in a second direction perpendicular to the first direction.