Offset Duct Speaker for Vehicle Pedestrian Warning
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Solution Overview
Problem
Conventional sound-producing devices for electric and hybrid vehicles are vulnerable to water and small stones entering through the duct, causing malfunctions when traveling at low speeds, as the duct extends downward and increases the risk of debris reaching the speaker.
Innovation Solution
A sound-producing device with a duct that has an offset inlet and outlet, fixed to a bracket on the vehicle body, and an impact-absorbing portion, made from flexible materials, which reduces the transmission of vibrations and debris, and includes a larger outlet diameter to enhance sound pressure amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the duct extends downward from the speaker straight to the opening, then the sound transmission efficiency is improved, but water or small stones can reach the speaker via the duct causing malfunction
Solution Approach 1:
The inlet and outlet of the duct are offset from each other in a direction intersecting the vertical axis, creating a three-dimensional offset configuration. This spatial arrangement prevents water and stones traveling vertically upward from reaching the speaker, while maintaining effective sound transmission through the duct structure.
Solution Approach 2:
The duct structure employs asymmetric inlet and outlet positioning rather than a symmetric vertical alignment. The offset configuration creates an asymmetric path that blocks debris while allowing acoustic energy transmission, resolving the contradiction between protection and simplicity.
2Stability of the object's composition
If the duct is made rigid for stable installation, then the mounting stability is improved, but vibration and impact from the road surface are transmitted to the speaker
Solution Approach 1:
The duct is constructed from flexible material that can deform to absorb vibrations and impacts from the road surface. This flexibility prevents harmful mechanical energy from being transmitted to the speaker while maintaining stable installation through the flexible connection to the vehicle body.
Solution Approach 2:
The impact-absorbing portion is incorporated into the duct structure to provide beforehand cushioning against vibrations and impacts. This pre-built cushioning mechanism protects the speaker from harmful mechanical energy before it can cause damage.
3Power
If the outlet diameter is increased to amplify sound pressure, then the sound transmission efficiency is improved, but the duct becomes more susceptible to deformation from impact
Solution Approach 1:
The duct employs a composite structure combining flexible material with a hard resin inlet. This composite construction allows the outlet to have sufficient diameter for sound pressure amplification while the overall structure maintains resistance to impact and deformation through the combined properties of different materials.
Solution Approach 2:
The duct structure serves multiple functions simultaneously: it amplifies sound pressure through adequate outlet diameter, absorbs vibrations through flexible material, and resists impact through the composite construction with hard resin inlet, eliminating the need to trade off between these competing requirements.
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 solution effectively prevents water and small stones from reaching the speaker, reduces vibration transmission, and improves noise and vibration performance within the vehicle compartment while amplifying the sound pressure of the simulated travel sound for pedestrian notification.
Implementation Method 1
a duct connecting the sound-producing means to the opening... efficiently transmitting the simulated travel sound generated by the speaker to the outside of the vehicle
Implementation Method 2
the duct main body is formed from a flexible material... make it difficult for vibration or an impact inputted into the vehicle body bottom part to be transmitted to the sound-producing means via the duct
Implementation Method 3
the inlet and the outlet are offset in a direction that intersects a vertical axis... prevent water or small stones scattered by a tire from passing through the duct
Data Source
AI summary
A sound-producing device for a vehicle includes sound-producing means, an opening provided in a vehicle body bottom part, and a duct connecting the sound-producing means to the opening, and it is possible, by amplifying the sound pressure of a sound generated by the sound-producing means through the duct and transmitting the sound to the outside of the vehicle via the opening of the vehicle body bottom part, to inform a pedestrian that the vehicle is approaching and alert them, and to reduce the sound pressure of the sound-producing means compared with a case in which there is no duct. Moreover, since an inlet and an outlet of the duct are offset from each other in a direction that intersects a vertical axis, it is possible to prevent water or small stones scattered by a tire from passing through the duct and to decrease the stiffness of the duct.