Automobile Sound Insulation Panel With Helmholtz Resonance
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Solution Overview
Problem
Conventional automobile sound insulation panels fail to achieve lightweight designs with improved sound isolation performance across a wide frequency band due to increased weight from overlaying sheet members, which also obstruct Helmholtz resonance and limit vibration frequency control.
Innovation Solution
An automobile sound insulation panel comprising a first panel member, a second panel member, and an elastic sheet member with projections and recesses forming independent air layers and a continuous air layer, allowing for vibration membranes that can freely vibrate and communicate holes to exhibit Helmholtz resonance, thereby enhancing sound isolation without increasing weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sheet member is overlaid on the resin structure to improve sound isolation performance, then sound isolation performance is improved, but weight of the sound insulation panel increases
Solution Approach 1:
The patent divides the sound insulation panel into multiple functional layers: a resin structure with cells, communication holes for Helmholtz resonance, and an elastic sheet member with vibration-absorbing portions. Each layer performs a specific function, allowing the system to achieve superior sound isolation without relying solely on increased weight from a single heavy sheet member.
Solution Approach 2:
The elastic sheet member is designed to vibrate at specific frequencies to counteract sound waves. The vibration-absorbing portions are strategically positioned to resonate with and absorb sound energy across different frequency ranges, improving sound isolation performance through active vibration control rather than passive mass blocking.
2Reliability
If a sheet member is overlaid on the resin structure to improve sound isolation performance, then sound isolation performance is improved, but the Helmholtz resonance is reduced
Solution Approach 1:
The patent segments the sound isolation mechanism into two independent but complementary systems: the Helmholtz resonance system (resin structure with communication holes) and the vibration absorption system (elastic sheet member). By separating these functions into different layers, the sheet member does not block the communication holes, allowing Helmholtz resonance to function effectively while the sheet member handles vibration absorption.
Solution Approach 2:
The elastic sheet member acts as an intermediary layer that absorbs vibrations without interfering with the Helmholtz resonance mechanism. It is positioned and designed to dampen structural vibrations while allowing air to move freely through the communication holes, thus mediating between the external sound environment and the internal resonance structure.
3Reliability
If the vibration frequency of the sheet member is not controlled, then the sound insulation effect is limited, but controlling it requires additional complexity
Solution Approach 1:
The elastic sheet member incorporates vibration-absorbing portions with specific local properties at strategically positioned locations. These portions have different material compositions or structural characteristics tailored to absorb specific frequency ranges, allowing the sheet member to effectively control vibrations across multiple frequencies without requiring a complex active control system.
Solution Approach 2:
The patent controls vibration frequency by changing the physical parameters of the vibration-absorbing portions, such as material density, thickness, and geometric configuration. By adjusting these parameters during design, the vibration absorption characteristics are optimized for target frequency ranges, achieving effective sound isolation without complex real-time control mechanisms.
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 structure achieves sound insulation effects surpassing the mass law, effectively isolating low-frequency sounds and expanding the sound isolation-target frequency band without weight increase, while maintaining effective Helmholtz resonance by strategically placing communication holes.
Implementation Method 1
Each of the communication holes and the individual air layers or the continuous air layer form a Helmholtz resonator
Implementation Method 2
a bottom of each of the recesses of the elastic sheet member functioning as a vibration membrane which is capable of freely vibrating
Data Source
AI summary
The present invention provides an automobile sound insulation panel which suitably implements a lightweight sound insulation panel with an expanded sound isolation-target frequency band and improved sound isolation performance. An automobile sound insulation panel includes a first panel member, a second panel member, and an elastic sheet member positioned between the first panel member and the elastic sheet member. The elastic sheet member includes a first projection-recess part. The first panel member abuts on respective upper opening edges of a plurality of recesses that form the first projection-recess part. Individual air layers exist between the second panel member and the elastic sheet member. A continuous air layer exists between the first panel member and the elastic sheet member.