Vehicle Approach Sound Guide Tubes for Directional Audible Cues

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Solution Overview

Problem

Pedestrians, especially those with visual impairment, find it difficult to determine whether a silent electric or hybrid vehicle is approaching or passing by based on the notification sound emitted by existing vehicle approach notification devices.

Innovation Solution

A vehicle approach notification device with sound guide tubes of different lengths that amplify sounds of specific frequencies, directing notification sounds in distinct directions to differentiate between approaching and passing vehicles, using a vibration plate to generate white noise and causing resonance in snail-shaped sound guide tubes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a single sound emitter outputs notification sound, then the device structure is simple, but pedestrians cannot determine whether the vehicle is approaching or passing by

Engineering Contradiction:

ImprovePedestrian's ability to determine vehicle approach statusVSAvoidSound emitter structure

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The sound emitter is divided into multiple independent sound guide tubes (first sound guide tube directed forward, second sound guide tube directed sideways) that can be controlled separately. This segmentation allows different notification sounds to be emitted in different directions, enabling pedestrians to determine whether the vehicle is approaching or passing by based on which sound guide tube emits sound.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sound guide tubes are assigned different directional characteristics and resonance frequencies. The first sound guide tube directed to the front area has different tube path length and resonates at a different frequency compared to the second sound guide tube directed sideways, creating local quality differences that provide directional audio information to pedestrians.

Inventive Principle:

Principle #3Local quality

2Ease of operation

If sound guide tubes have different lengths to produce different frequencies, then directional sound differentiation is achieved, but the device size increases

Engineering Contradiction:

ImproveDirectional sound differentiationVSAvoidDevice volume

Core Design Contradiction:

Ease of operationVSVolume of moving object

Solution Approach 1:

The sound guide tubes are designed with spiral (snail-shaped) internal passages instead of straight tubes. This curvature allows the sound wave to travel a longer path length within a compact volume, enabling different resonance frequencies to be achieved without proportionally increasing the overall device size. The spiral structure efficiently packs the acoustic path into a small space.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Volume of moving object

If straight sound guide tubes are used, then the device is compact, but resonance frequency control and sound amplification are insufficient

Engineering Contradiction:

ImproveDevice compactnessVSAvoidSound amplification through resonance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The spiral internal passage structure extends the sound wave path length within a compact tube volume, allowing the tube to function as an effective resonance chamber. The curved path enables the sound wave to undergo multiple reflections and build up resonance at specific frequencies determined by the total path length, achieving both compactness and effective sound amplification.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The sound guide tubes are designed to resonate at specific frequencies corresponding to their spiral path lengths. By controlling the vibration frequency of the sound source to match the resonant frequency of each tube, strong sound amplification is achieved through resonance, ensuring reliable notification sound output from the compact spiral structure.

Inventive Principle:

Principle #18Mechanical vibration

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

Enables pedestrians to easily distinguish between an approaching and passing vehicle, enhancing safety by providing distinct audible cues, while allowing the device to be compact due to the use of spiral sound guide tubes, and generating diverse resonance sounds across a wide frequency band.

Implementation Method 1

Each of the sound guide tubes is configured to amplify a sound having a frequency corresponding to a tube path length of the sound guide tube by causing the sound generated by the vibration plate to resonate

Methodology Applied

Scientific EffectResonance: Resonance

Data Source

PatentUS12466314B2Vehicle approach notification device

Publication Date: 2025.11.11 TOYOTA JIDOSHA KK

AI summary

A vehicle approach notification device includes a sound emitter configured to output a notification sound. The sound emitter includes a vibration plate that generates sound, and sound guide tubes that outputs the notification sound toward an outside of the vehicle. The sound guide tubes include a first sound guide tube directed to a front area in front of the vehicle, and a second sound guide tube directed in a direction different from a direction in which the first sound guide tube is directed. Each of the sound guide tubes is configured to amplify a sound having a frequency corresponding to a tube path length of the sound guide tube by causing the sound generated by the vibration plate to resonate. The tube path length of the first sound guide tube and the tube path length of the second sound guide tube are different from each other.