Concentric Radial Ring Motor Eliminates Ferrous Pole Mass

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Solution Overview

Problem

Conventional loudspeakers face efficiency limitations due to heat generation in voice-coil conductors, leading to reduced sound pressure output and increased weight, making them unsuitable for vehicular applications, as they require large motor structures to dissipate heat and often rely on ferrous materials that increase inductance and weight.

Innovation Solution

A voice-coil transducer design using two radially concentric and radially polarized magnets with a voice-coil positioned between them, supported by a chassis that also acts as a heat sink, eliminating the need for ferrous pole materials and enhancing magnetic field strength and heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If ferrous pole materials are used to create the magnetic circuit, then the magnetic field can be directed into the air gap, but the total mass of the system increases significantly

Engineering Contradiction:

Improvemagnetic field directionVSAvoidtotal mass

Core Design Contradiction:

ForceVSWeight of stationary object

Solution Approach 1:

The patent removes ferrous pole materials from the magnetic circuit, extracting the harmful heavy components while maintaining the essential magnetic field guidance function through alternative means, thereby resolving the contradiction between magnetic field direction capability and system mass

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs composite material structures in the magnet assembly that eliminate the need for traditional ferrous pole pieces, using materials that provide both magnetic field guidance and reduced weight characteristics simultaneously

Inventive Principle:

Principle #40Composite materials

2Force

If ferrous pole materials are used to guide the magnetic field, then the magnetic circuit is established, but the voice-coil inductance increases

Engineering Contradiction:

Improvemagnetic field guidanceVSAvoidvoice-coil inductance

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The patent extracts ferrous pole materials from the magnetic circuit, eliminating the source of excessive voice-coil inductance while preserving the magnetic field guidance function through alternative structural arrangements

Inventive Principle:

Principle #2Taking out (Extraction)

3Loss of energy

If a large motor structure is used to dissipate heat, then the heat dissipation capacity increases, but the loudspeaker becomes very large and heavy

Engineering Contradiction:

Improveheat dissipationVSAvoidloudspeaker weight

Core Design Contradiction:

Loss of energyVSWeight of stationary object

Solution Approach 1:

The patent removes heavy ferrous materials that contribute to both mass and heat accumulation, enabling more efficient heat dissipation pathways while significantly reducing the overall weight and size of the loudspeaker system

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses composite material constructions that provide superior thermal management characteristics without the weight penalty of traditional ferrous-based heat dissipation structures

Inventive Principle:

Principle #40Composite materials

4Power

If the voice-coil operates at higher temperatures, then the resistance increases, but the power input is converted mostly into heat rather than sound

Engineering Contradiction:

Improvepower inputVSAvoidheat generation

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The patent converts the harmful heat generation issue into a beneficial thermal management system by designing the motor structure to actively dissipate heat through eliminated ferrous materials, transforming the problem of heat accumulation into an efficient heat dissipation mechanism that maintains lower operating temperatures and reduces energy loss

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 increases loudspeaker efficiency, reduces weight by up to 60%, maintains consistent magnetic field interaction, and improves linearity, allowing for higher power output while minimizing heat-related inefficiencies and weight constraints.

Implementation Method 1

the resistance of the conductive material of the voice-coil causes the production of heat in the voice-coil or winding

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The magnets produce magnetic flux in the air gap

Methodology Applied

Scientific EffectMagnetic flux: Magnetic Field

Implementation Method 3

The interaction between the current passing through the voice-coil and the magnetic field produced by the permanent magnet causes the voice-coil to oscillate

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentUS7706563B2Concentric radial ring motor

Publication Date: 2010.04.27 HARMAN INT IND INC

AI summary

A voice-coil transducer includes two radially concentric magnets, a voice-coil located in the gap between the inner and outer magnets, and a diaphragm coupled to the voice-coil. An audio loudspeaker includes the voice-coil transducer with two radially concentric magnets, a voice-coil located within the gap between the inner and outer magnets, a diaphragm coupled to the voice-coil in order to create sounds from the voice-coil, and a chassis to support the magnets, voice-coil, and diaphragm.