Horn Device Frequency Control for Abnormal Noise

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Solution Overview

Problem

Conventional horn devices produce abnormal noise due to increased attraction force of the electromagnet at low temperatures, causing collisions between the fixed and movable iron cores.

Innovation Solution

The horn device adjusts the vibration frequency of the diaphragm based on temperature and voltage measurements to prevent resonance and thus avoid collisions between the iron cores, by reducing the vibration frequency when temperatures drop below -30°C or voltage exceeds 15V.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the horn device operates at low temperature, then the electromagnet attraction force increases, but the fixed iron core collides with the movable iron core causing abnormal noise

Engineering Contradiction:
Improveelectromagnet attraction forceVSAvoidabnormal noise
Core Design Contradiction:
ForceVSObject-generated harmful factors

Solution Approach 1:

The patent changes the vibration frequency parameter of the diaphragm based on temperature conditions. When low temperature is detected, the control unit adjusts the vibration frequency to a lower value, which changes the operating parameters of the electromagnet to prevent excessive attraction force and subsequent core collision, thereby eliminating abnormal noise while maintaining functional performance

Inventive Principle:
Principle #35Parameter changes

2Force

If the voltage value is high, then the electromagnet attraction force increases, but the fixed iron core collides with the movable iron core causing abnormal noise

Engineering Contradiction:
Improveelectromagnet attraction forceVSAvoidabnormal noise
Core Design Contradiction:
ForceVSObject-generated harmful factors

Solution Approach 1:

The patent implements a feedback control mechanism where the control unit continuously monitors the voltage value supplied to the horn device. When high voltage is detected, the system automatically adjusts the vibration frequency to a lower value, creating a closed-loop control that prevents excessive electromagnet attraction force and the resulting abnormal noise, ensuring stable operation across varying voltage conditions

Inventive Principle:
Principle #23Feedback

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 adjustment effectively prevents the production of abnormal noise by deviating the vibration frequency from the resonance frequency, inhibiting collisions and maintaining sound quality.

Implementation Method 1

a temperature measurement part that measures a temperature of the horn device

Methodology Applied
Scientific EffectTemperature measurement:

Implementation Method 2

a voltage measurement part that measures a voltage value of a power supply for the horn device

Methodology Applied
Scientific EffectVoltage measurement:

Implementation Method 3

vibrates a diaphragm at a predetermined vibration frequency by magnetic force of an electromagnet generated by energization

Methodology Applied
Scientific EffectMagnetic force: Electromagnet

Implementation Method 4

resonate by a resonator the sound produced by the vibration to produce sound

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP3382691B1Horn device
Publication Date: 2021.05.26 MITSUBA CORP
  • EP3382691B1 patent drawingFigure 1
  • EP3382691B1 patent drawingFigure 2~3
  • EP3382691B1 patent drawingFigure 4~5

AI summary

A horn device (A), which is capable of preventing production of abnormal noise is provided. The horn device (A) which resonates, by a resonator (1), sound produced by vibrating a diaphragm (21) and comprises: a control part (34), which vibrates the diaphragm (21); a temperature measurement part (30), which measures the temperature inside the horn device (A); and a voltage measurement part (31), which measures the voltage value used to vibrate the diaphragm (21); wherein the control part (34) deviates a vibration frequency which vibrates the diaphragm (21) from a resonance frequency (fc) according to at least any of the temperature measured by the temperature measurement part (30) and the voltage value measured by the voltage measurement part (31).