Foamed Coil Antenna for Load Absorption

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional coil antennas for short distance communication systems in the LF band face damage to the magnetic core due to static deformation and load, as the rigid potting material does not absorb loads effectively, leading to resonance frequency changes and instability in the magnetic field.

Innovation Solution

A coil antenna design incorporating a foamed component with uniformly generated bubbles, such as urethane foam or silicone foam, between the winding structure and the case, which absorbs static and sudden loads, preventing damage to the magnetic core and improving impact resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid potting material is used to fill the case, then the magnetic core is protected from environmental factors, but the magnetic core is damaged by static deformation and load

Engineering Contradiction:

Improveprotection from temperature and humidityVSAvoidmagnetic core integrity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The patent changes the physical parameters of the potting material from rigid to foamed structure. The foamed component maintains the protective function against temperature and humidity while its cellular structure provides flexibility to absorb static deformation and load, preventing damage to the magnetic core.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses a composite structure where a foamed component is combined with the case and winding structure. The foamed material integrates the protective properties against environmental factors with the mechanical property of absorbing deformation, creating a composite system that resolves the contradiction between protection and core integrity.

Inventive Principle:

Principle #40Composite materials

2Reliability

If a degasified component is used to fill the case, then the magnetic core is protected from environmental factors, but the component cannot respond to sudden loads

Engineering Contradiction:

Improveprotection from environmental factorsVSAvoidresponsiveness to sudden load

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The patent introduces bubbles into the potting material to create a foamed structure. This parameter change allows the material to maintain environmental protection while gaining the ability to rapidly deform and absorb sudden loads through the collapse and compression of air pockets in the foam structure.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the case is fully packed with potting material, then the magnetic core is protected from environmental factors, but the magnetic core is damaged by momentary deformation

Engineering Contradiction:

Improveprotection from temperature and humidityVSAvoidmomentary load transmission

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent transforms the rigid potting material into a foamed component with cellular structure. This parameter change enables the material to absorb momentary deformation through the compression and expansion of foam cells, preventing the transmission of harmful loads to the magnetic core while maintaining environmental protection.

Inventive Principle:

Principle #35Parameter changes

4Reliability

If vacuum casting is used to fill the case, then bubbles are removed and the magnetic core is protected, but displacement is generated in the magnetic core during curing

Engineering Contradiction:

Improveprotection from environmental factorsVSAvoidmagnetic core position stability

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent extracts the harmful bubbles from the potting material by using a foamed component structure where bubbles are intentionally created as part of the material design rather than being removed. This eliminates the displacement problem during curing while maintaining the protective function.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the curing process parameters by using a foamed component that can be cured without generating displacement. The foamed structure allows for more uniform curing and reduced shrinkage, maintaining magnetic core position stability while achieving environmental protection.

Inventive Principle:

Principle #35Parameter changes

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 foamed component allows for rapid absorption of loads, reducing the risk of magnetic core damage, enhancing impact resistance, and maintaining the magnetic core's stability, while also reducing the overall weight of the antenna.

Implementation Method 1

a foamed component is provided in at least a portion of a space between the winding structure and the case... the deformation and the load can be absorbed faster

Methodology Applied

Scientific EffectViscoelasticity: Viscoelasticity

Implementation Method 2

it may preferably be a foam or sponge of urethane foam or silicone foam... in comparison with the above-mentioned degasified component, the deformation and the load can be absorbed faster

Methodology Applied

Scientific EffectFoam deformation: Foam

Data Source

PatentUS7425929B2Coil antenna

Publication Date: 2008.09.16 MURATA MFG CO LTD

AI summary

A coil antenna includes a magnetic core and a coil wound around a bobbin which are accommodated within a case. The magnetic core and an end of the bobbin are connected to a cap. The magnetic core and an end portion of the bobbin are covered with a foamed component, and are further covered with a gel component. The foamed component is formed by a forming process, and an adhesive compound is provided between the magnetic core and the foamed component.