Multilayer Acoustic Baffle for Vehicle Headliners
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Solution Overview
Problem
Existing multilayer composites used in vehicle interiors for sound control face challenges in improving acoustic performance and airflow resistance while maintaining simplicity of construction and ease of manufacture.
Innovation Solution
A multilayer acoustic baffle construction comprising a coverstock, spunbond nonwoven, fiberglass, polymeric foam, and porous bicomponent nonwoven layers, with specific thickness and basis weight ranges, and the use of adhesive layers that control film formation to optimize sound absorption and airflow, formed through a heating and pressing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If multilayer composites are used to reduce noise levels in vehicle interiors, then sound absorption is improved, but construction complexity and manufacturing difficulty increase
Solution Approach 1:
The patent combines multiple functional layers (acoustic foam, fabric layers, adhesive layers) into a single integrated multilayer composite structure that is formed and cured as one unit. This merging approach maintains the sound absorption benefits of multiple layers while simplifying construction and manufacturing by eliminating the need to assemble separate components.
Solution Approach 2:
The invention uses a composite material structure consisting of an acoustic foam layer bonded to fabric layers with adhesive layers in between. This composite construction achieves superior noise reduction performance by combining the sound-absorbing properties of foam with the surface properties of fabric, while the integrated formation process keeps manufacturing complexity manageable.
2Object-affected harmful factors
If multilayer composites are used to reduce noise levels in vehicle interiors, then sound absorption is improved, but manufacturing ease decreases
Solution Approach 1:
The adhesive layers are pre-applied to the acoustic foam layer before final assembly, and the entire structure is formed and cured in a single manufacturing process. This preliminary preparation of adhesive bonding surfaces and integrated formation approach improves manufacturing ease by reducing the number of separate steps required while maintaining effective sound absorption.
3Strength
If adhesive layers are used to bond multilayer composites, then layer bonding is improved, but airflow resistance may be compromised
Solution Approach 1:
The adhesive layers are positioned specifically at the interfaces between the acoustic foam layer and fabric layers, where bonding is needed, while leaving the interior porous structure of the foam and the airflow paths within the fabric layers untouched. This localized application of adhesive ensures strong layer bonding without compromising the overall airflow characteristics of the composite structure.
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 provides improved sound absorption coefficients over a wide frequency range without the need for additional acoustic pads, allowing for adjustable sound attenuation characteristics and maintaining desired airflow resistance, enhancing both acoustic performance and manufacturing simplicity.
Implementation Method 1
a first adhesive layer present as particles with an average particle size in the range of 50 μm to 250 μm and at basis weight of 25 g/m2 to 55 g/m2 at a thickness of 0.1 mm to 0.5 mm
Implementation Method 2
heating said layered construction and pressing to form said acoustic baffle
Implementation Method 3
a porous bicomponent nonwoven fiber layer at a thickness of 0.25 mm to 0.40 mm having a basis weight of 40 g/m2 to 100 g/m2 including monofilament fibers present at 0.05 dtex to 2.5 dtex
Implementation Method 4
multilayer composites for sound control have been employed in headliners, trunk liners, hood liners, dash mats, interior panels, carpeting and in other vehicular trim panel components to regulate noise reduction in the vehicle interior
Implementation Method 5
a polymeric foam layer at a thickness of 4.0 mm to 7.0 mm at a density of 1.2 lbs./ft.3 to 3.6 lbs./ft.3
Implementation Method 6
a porous bicomponent nonwoven fiber layer at a thickness of 0.25 mm to 0.40 mm having a basis weight of 40 g/m2 to 100 g/m2
Data Source
AI summary
The present invention is directed to an acoustical baffle that has use in vehicle interiors, such as an interior headliner. In particular, the baffle can provide improved acoustics while maintaining a desired airflow resistance and can be configured to provide for different sound attenuation characteristics at selected locations of the baffle construction.