Common-Mode Choke Coil Flange Slopes for Wire Breakage Prevention

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Solution Overview

Problem

Common-mode choke coils experience wire breakage due to stress and movement between the winding core and electrodes, particularly when resin is molded around the coil, causing thermal expansion and contraction.

Innovation Solution

The design incorporates flange portions with slopes that guide the extended wire portions to electrodes, reducing movement and exposure, and features a groove for secure fitting, with an inclination angle between 5 to 20 degrees to minimize load and separation, and a plating structure to enhance bonding strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If extended portions of wires are electrically connected to electrodes at flange portions, then electrical connection is achieved, but stress is applied to wire portions between winding core and electrodes causing breakage

Engineering Contradiction:

Improvewire connection reliabilityVSAvoidwire strength

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent applies preliminary action by forming slopes on the flange portions before wire connection. These slopes pre-guides the extended portions of wires along a controlled path to the electrodes, preventing stress concentration and movement that would otherwise occur during assembly and operation. This preliminary structural preparation ensures reliable electrical connection while protecting wire strength.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If wires are exposed for electrical connection, then electrode connectivity is achieved, but wires are vulnerable to resin intrusion and thermal expansion causing breakage

Engineering Contradiction:

Improveelectrical connectivityVSAvoidresin intrusion and thermal stress

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The slopes act as an intermediary structure between the exposed wire extended portions and the surrounding environment. They guide wires to electrodes while their geometric form creates a barrier that prevents resin from reaching the wires during molding. This intermediary structure simultaneously enables electrical connectivity and protects against harmful factors like resin intrusion and thermal expansion.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Stability of the object's composition

If flange portions are added with slopes, then wire movement is suppressed, but device complexity increases

Engineering Contradiction:

Improvewire position stabilityVSAvoidcore structure complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent merges the slope structure directly into the flange portions of the core, combining multiple functions into a single integrated component. The flange portions simultaneously provide mechanical support, electrical connection surfaces, and wire guidance through their sloped geometry. This merging approach suppresses wire movement while avoiding the need for separate guiding structures, thus not increasing overall device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11837396B2Common-mode choke coil

Publication Date: 2023.12.05 MURATA MFG CO LTD

AI summary

A coil component includes a drum core that includes a winding core portion and a pair of flange portions formed at the ends of the winding core portion, electrodes that are included in the pair of flange portions, and first and second wires that are wound around the winding core portion and that include extended portions electrically connected to the electrodes. The flange portions are continuous with the winding core portion and have slopes that guide the extended portions to the electrodes.