Pressed-Core Inductor With Narrowed Coil Ends for Crack-Free Terminals

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Solution Overview

Problem

Existing inductors face challenges in downsizing while maintaining high current handling capabilities, as increasing the thickness of flat conductors to reduce DC resistance can lead to cracking when forming terminals.

Innovation Solution

An inductor design featuring a magnetic core formed by pressing a powdered magnetic material and binder, with a coil part and external electrode made of a flat conductor, where the end portions protruding from the magnetic core have a width less than the average width of the coil part inside, allowing for easier bending and enhanced reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the thickness of the flat conductor is increased to reduce DC resistance, then the current handling capability is improved, but the terminal formation process causes cracking and reduces reliability

Engineering Contradiction:

Improveterminal strengthVSAvoidterminal formation difficulty

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The flat conductor is divided into two distinct width portions: a first width portion inside the magnetic core and a second width portion protruding from it. This segmentation allows each portion to serve different functions - the first portion provides current carrying capacity while the second portion facilitates easy terminal formation without cracking.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different width characteristics are applied to different locations of the flat conductor. The first width portion has greater width for low DC resistance, while the second width portion has reduced width for easy bending and terminal formation. This local differentiation resolves the contradiction between current handling and manufacturability.

Inventive Principle:

Principle #3Local quality

2Strength

If the width of the end portion protruding from the magnetic core is increased to improve terminal strength, then the current handling capability is improved, but the bending process becomes difficult and may cause cracking

Engineering Contradiction:

Improveterminal strengthVSAvoidbending difficulty

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The flat conductor's width is segmented into two portions along its length. The first portion inside the magnetic core maintains greater width for strength, while the second protruding portion has reduced width for ease of bending, eliminating the need to compromise between these conflicting requirements.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The flat conductor is pre-formed with different width portions before being embedded in the magnetic core. This preliminary shaping ensures that the protruding end portion is already optimized for bending, preventing cracking during the terminal formation process while maintaining adequate strength.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20240170200A1inductor

Publication Date: 2024.05.23 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

An object is to provide a small and highly reliable inductor capable of handling a large current. The inductor includes: magnetic core formed by pressing a mixture of a powdered magnetic material and a binder; coil part disposed inside magnetic core; and external electrode formed by bending end portion of coil part protruding from magnetic core. Coil part and external electrode are made of a flat conductor, and a width of end portion of coil part protruding from magnetic core is less than an average width of coil part disposed inside magnetic core.