In-Tire Sound Absorber Dual-Layer Fibrous Design
Solution Overview
Problem
Existing in-tire sound absorbers are prone to damage during tire fitment and lack sufficient strength to withstand operational forces, leading to ineffective noise reduction in pneumatic tires.
Innovation Solution
A dual-layer sound absorber system comprising a first fibrous layer with low air flow resistance and a second fibrous layer with higher air flow resistance, oriented perpendicular to the wheel rim, providing increased tensile strength and sound absorption, along with a porous insert shaped to avoid damage during fitment, utilizing non-woven fibrous webs and a hook and loop attachment for secure installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a noise damper made from porous material is used to reduce tonal noise, then sound absorption is improved, but the noise damper is damaged during tire fitment or breaks apart during operation
Solution Approach 1:
The patent applies composite materials by combining multiple fibrous layers with different air flow resistance properties. The first layer has low air flow resistance to allow sound wave propagation, while the second layer has high air flow resistance for sound absorption. This composite structure maintains both noise reduction effectiveness and structural durability during fitment and operation.
Solution Approach 2:
The patent applies local quality by creating layers with different local properties - the first layer is designed with low air flow resistance for sound wave transmission, while the second layer is designed with high air flow resistance for sound absorption. Each layer has optimized local characteristics suited to its specific function within the overall sound absorption system.
2Object-generated harmful factors
If conventional bulky non-woven fabrics with cross-lapped fibers are used, then sound absorption is provided, but tensile strength is insufficient to resist centrifugal forces during wheel rotation
Solution Approach 1:
The patent applies parameter changes by modifying the fiber orientation parameter from cross-lapped to substantially perpendicular orientation relative to the wheel rim surface. This parameter change significantly increases tensile strength in the direction perpendicular to the wheel rim surface, enabling the sound absorber to withstand centrifugal forces during wheel rotation while maintaining its noise reduction function.
3Ease of manufacture
If a single-layer sound absorber is used, then manufacturing is simplified, but sound absorption effectiveness across different frequencies is reduced
Solution Approach 1:
The patent applies segmentation by dividing the sound absorber into multiple functional layers - a first layer with low air flow resistance and a second layer with high air flow resistance. This segmentation allows each layer to perform its specific function optimally, with the first layer allowing sound wave propagation and the second layer providing sound absorption, thereby improving overall noise reduction effectiveness while maintaining manufacturing feasibility.
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 system effectively reduces tonal noise by up to 9 decibels within the 0-600 Hz frequency range, enhancing the durability and longevity of the sound absorber while ensuring safe fitment and operation.
Implementation Method 1
The low air flow resistance of the first layer allows the standing sound pressure wave to propagate within the layer
Implementation Method 2
The excited air particles are thereby forced through the high air flow resistance of the second layer to provide the sound absorption
Data Source
AI summary
An in-tire sound absorber for a pneumatic wheel assembly including a wheel rim and a tire fitted to the wheel rim. The sound absorber is adapted to be located within a cavity defined by the wheel rim and the tire. The sound absorber comprises a first fibrous layer and a second fibrous layer. The second fibrous layer has a higher air flow resistance than the first fibrous layer. The first fibrous layer, the second fibrous layer, or both, is made from a non-woven fibrous web.