Inductor Terminal Recess Structure to Prevent Magnetic Saturation
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Solution Overview
Problem
Conventional inductors experience a decrease in magnetic saturation current due to the shape of their exterior members, which also limits the connection strength to circuit boards when terminal electrodes are extended onto the side surfaces, leading to increased surface area and potential magnetic saturation.
Innovation Solution
An inductor design featuring an exterior member with recesses on its side surfaces to house terminal electrodes, while maintaining a thicker wall thickness by using lead portions with a smaller thickness than the coil wire, preventing magnetic saturation and ensuring secure connection to circuit boards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If terminal electrodes are extended onto the side surfaces of the exterior member, then connection strength to circuit boards is improved, but surface area for mounting increases and magnetic saturation may occur
Solution Approach 1:
The patent utilizes the vertical dimension by forming recesses in the side surfaces of the exterior member to house the terminal electrodes. This allows the electrodes to be positioned in three-dimensional space rather than only on the surface, enabling secure connections without increasing the mounting footprint on the circuit board.
Solution Approach 2:
The terminal electrodes are nested within recesses formed in the exterior member. This nesting arrangement allows the electrodes to be contained within the overall structure of the inductor, providing connection points without extending the external dimensions or surface area required for mounting.
2Ease of operation
If wall thickness is reduced to accommodate terminal electrodes on side surfaces, then ease of connection is improved, but magnetic saturation current decreases
Solution Approach 1:
By moving terminal electrodes into recesses on the side surfaces rather than extending them along the bottom surface, the design utilizes the vertical and lateral dimensions of the exterior member. This allows adequate wall thickness to be maintained in the bottom surface for magnetic performance while still providing accessible connection points on the sides.
Solution Approach 2:
The exterior member is designed with non-uniform geometry, featuring recesses in specific locations where terminal electrodes are needed. This local modification allows the majority of the exterior member to maintain sufficient thickness for magnetic saturation current, while only localized areas are modified to accommodate electrical connections.
3Strength
If lead portions have larger thickness for structural strength, then mechanical strength is improved, but magnetic saturation current decreases due to reduced exterior member wall thickness
Solution Approach 1:
The lead portions are designed with differentiated thickness characteristics - thicker in regions requiring mechanical strength and thinner in regions adjacent to the exterior member wall. This localized variation in thickness allows the structure to maintain both mechanical integrity and adequate magnetic performance by preserving wall thickness where it matters most for magnetic saturation current.
Solution Approach 2:
The lead portions are segmented into different functional zones with different thickness requirements. The portion requiring structural strength has larger thickness, while the portion near the exterior member wall has smaller thickness to maintain adequate wall thickness. This segmentation allows optimization of both mechanical and magnetic properties in different regions.
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 inhibits the decrease in magnetic saturation current and maintains a secure connection to circuit boards by preventing magnetic saturation and allowing for solder fillet formation without increasing the surface area for mounting.
Implementation Method 1
an exterior member (10) including a magnetic material
Implementation Method 2
a coil portion (21) covered by the exterior member
Data Source
AI summary
An inductor includes: an exterior member having a bottom surface and a side surface; and an electric conductive member partially covered by the exterior member. The electric conductive member includes a coil portion covered by the exterior member; lead portions connected to both ends of the coil portion, extending toward the bottom surface, and covered by the exterior member; and terminal electrodes connected to the lead portions and exposed from the bottom surface. The side surface includes recesses recessed inward of the exterior member from the side surface and connected to the bottom surface. The terminal electrodes extend along the bottom surface toward the recesses, are bent from the bottom surface toward the recesses, and housed therein. At least a part of each lead portion is opposite to the recess. Each lead portion has a thickness smaller than a diameter or a thickness of a wire of the coil portion.