Damping Spring With Composite Layers For Bone Conduction Transducers

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Solution Overview

Problem

Wearable bone-conduction transducers cause buzzing and irritation due to the lack of effective damping in steel springs, which leads to discomfort during audio transmission.

Innovation Solution

The use of damping steel with a rubbery inner layer and stainless steel outer layers in the springs, combined with laser welding techniques, to reduce resonant vibrations and improve user comfort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If traditional steel springs are used in bone-conduction transducers, then the device structure is simple and manufacturing is easy, but the springs cause buzzing and irritation due to lack of effective damping

Engineering Contradiction:
Improvebuzzing and irritationVSAvoidspring structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies composite materials by constructing the spring from multiple layers: an inner core of damping steel and outer layers of stainless steel. This composite structure combines the high damping capability of damping steel with the corrosion resistance and structural integrity of stainless steel, thereby reducing buzzing and irritation while maintaining simple device architecture and ease of manufacturing.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If damping steel springs are used to reduce buzzing, then user comfort is improved, but the resonant frequency shifts and requires precise control

Engineering Contradiction:
Improvevibration amplitudeVSAvoidresonant frequency control
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The patent employs parameter changes by carefully selecting and controlling the thickness of each spring layer (inner damping steel core and outer stainless steel layers). By adjusting these dimensional parameters, the resonant frequency of the spring can be precisely controlled to avoid unwanted vibrations while maintaining effective damping. The laser welding parameters are also optimized to achieve precise control over the joint properties without introducing excessive heat distortion.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If laser welding is used to attach damping steel springs, then welding precision and comfort are improved, but specific welding parameters must be precisely controlled

Engineering Contradiction:
Improvewelding qualityVSAvoidwelding parameter control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by optimizing specific laser welding parameters including laser power, welding speed, and focal position. These parameters are carefully controlled to achieve high welding quality and reliability while preventing defects such as burn-through or insufficient penetration. The inner diameter of the spring and the position of the laser beam are precisely coordinated to ensure consistent weld quality across production batches.

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

This solution effectively reduces buzzing and irritation by shifting the resonant frequency and decreasing vibration amplitude, enhancing the user experience and freeing up processing power for other functions.

Implementation Method 1

an electromagnet having a conductive coil. The conductive coil is configured to be driven by an electrical input signal to generate magnetic fields

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The pair of cantilevered arms are formed from damping steel... effectively reduces buzzing and irritation by shifting the resonant frequency and decreasing vibration amplitude

Methodology Applied
Scientific EffectDamping: Damping

Implementation Method 3

buzzing and irritation may be reduced by laser welding the damping steel springs using specific parameters

Methodology Applied
Scientific EffectLaser welding: Laser Beam Welding

Data Source

PatentEP3375206B1Damping spring
Publication Date: 2021.03.31 GOOGLE LLC
  • EP3375206B1 patent drawingFigure 1
  • EP3375206B1 patent drawingFigure 2A
  • EP3375206B1 patent drawingFigure 2B

AI summary

Embodiments disclosed in the present disclosure relate to vibration transducers. Such a transducer includes an electromagnet having a conductive coil. The conductive coil is configured to be driven by an electrical input signal to generate magnetic fields. The transducer further includes a magnetic diaphragm that is configured to mechanically vibrate in response to the generated magnetic fields. Additionally, the transducer includes a pair of cantilevered arms formed from damping steel. The cantilevered arms couple the magnetic diaphragm to a frame. The magnetic diaphragm vibrates with respect to the frame when the electromagnet is driven by the electrical input signal. Additionally, the pair of flexible support arms are connected to opposing sides of the magnetic diaphragm.