Wireless Power Feeding Coil Rib Structure for Magnetic Core Protection

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Solution Overview

Problem

Existing wireless power transmission devices face inadequate protection for magnetic cores when subjected to loads, as they are brittle and vulnerable to shock and stress, leading to insufficient protection mechanisms.

Innovation Solution

A power feeding coil unit design featuring a base portion with a magnetic body, a power feeding coil wound on the magnetic body, a cover portion, and a rib extending from the base portion to the cover portion, creating a space that absorbs loads and prevents stress from being applied directly to the magnetic body, with additional features like a central convex portion and protruding portions to enhance load-bearing capabilities and prevent deflection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If low-shrinkage resin is used to fill the space between coil conductive wires to protect the magnetic core, then the magnetic core is protected from direct contact, but stress is dispersed through the resin and still applied to the core when a load is applied

Engineering Contradiction:

Improveprotection of magnetic coreVSAvoidresistance to shock and load

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent introduces a rib structure as an intermediary element between the magnetic core and the external load. The rib extends from the base portion toward the cover portion and is positioned between the magnetic plates and the coil wires, creating a mechanical mediator that intercepts and redirects stress away from the magnetic core before it can be transmitted through the resin

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent segments the protective structure by introducing a rib that divides the space between magnetic plates. This segmentation creates multiple load paths and prevents stress concentration on the magnetic core, as the rib structure distributes the mechanical load across multiple support points

Inventive Principle:

Principle #1Segmentation

2Loss of energy

If the magnetic core is directly mounted on the base portion to improve magnetic coupling, then power transmission efficiency is improved, but the magnetic core is vulnerable to loads when the power feeding coil is placed on the ground

Engineering Contradiction:

Improvepower transmission efficiencyVSAvoidload and shock from vehicle tires

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent implements beforehand cushioning by pre-installing the rib structure between the magnetic core and the base portion before operational loads are applied. This rib structure acts as a pre-positioned protective element that absorbs and redistributes mechanical stress, cushioning the magnetic core against future loads from vehicle tires or other external forces

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If the magnetic core is made from magnetic material to achieve high magnetic permeability, then magnetic coupling is improved, but the core becomes brittle and very weak against shock and load

Engineering Contradiction:

Improvemagnetic couplingVSAvoidstrength against shock and load

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The rib structure serves as a mechanical intermediary that decouples the magnetic function from the mechanical strength requirements. The magnetic core can remain made of brittle magnetic material optimized for magnetic coupling, while the rib structure provides the necessary mechanical support and shock resistance, separating the magnetic and structural functions

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The design effectively protects the magnetic body from loads and stress by distributing the load through the rib and cover portion structure, preventing direct application to the magnetic body and enhancing the overall load-bearing performance, thus ensuring the magnetic body's safety.

Implementation Method 1

A wireless power transmission device is a technology for wirelessly supplying power from a power feeding coil to a power receiving coil by utilizing an electromagnetic induction or a resonance of a magnetic field

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

Methodology Applied

Scientific EffectMagnetic field resonance: Resonance

Implementation Method 3

a soft magnetic core with a high magnetic permeability is used to increase the magnetic coupling between the feeding and receiving coils

Methodology Applied

Scientific EffectMagnetic permeability: Magnetism

Data Source

PatentUS10404102B2Power feeding coil unit, wireless power feeding device and wireless power transmission device

Publication Date: 2019.09.03 TDK CORP

AI summary

A power feeding coil unit for wireless power transmission including a base portion with bottom having an opening on an upper end, a magnetic body having a plurality of magnetic plates disposed on a bottom surface of the base portion, a power feeding coil formed by winding a conductive wire on the magnetic body, a cover portion covering the opening of the base portion, and a rib extending from the base portion toward the cover portion between the plurality of magnetic plates and between the wires of the conductive wires, wherein, a distance between the rib and the cover portion is smaller than a distance between the power feeding coil and the cover portion.