Fibrous Noise Absorber Rim Adhesion for Cavity Noise
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Solution Overview
Problem
Current noise absorbers for vehicle wheels increase wheel mass, risk wheel imbalance, and are costly, while also posing challenges during tire mounting due to their placement inside the tire cavity, which generates cavity noise that disturbs drivers.
Innovation Solution
A noise absorbing arrangement comprising a fibrous material core with an outer woven sheet and an adhesion element, where the fibrous material is expandable and porous, attached to the wheel rim using a narrower adhesion element that allows the noise absorbing member to change shape under centrifugal forces, improving noise absorption without adding mass or causing imbalance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If noise absorbent material is placed in the tire cavity, then noise absorption performance is improved, but wheel mass increases
Solution Approach 1:
The patent employs a porous noise absorbent material with open-cell structure that allows sound waves to penetrate and be absorbed. The porous structure provides high noise absorption coefficient in the critical 150-250 Hz frequency range while maintaining extremely low density (approximately 0.05-0.1 g/cm³), thus achieving effective noise reduction without significantly increasing wheel mass
Solution Approach 2:
The invention uses a composite material structure combining a lightweight polymer base (such as polyurethane or polyethylene foam) with distributed fibrous additives. This composite approach optimizes both acoustic absorption properties and mechanical durability while keeping the material density low, thereby reducing the mass penalty compared to traditional solid noise barriers
2Object-affected harmful factors
If noise absorbent material is placed in the tire cavity, then noise absorption performance is improved, but wheel balance stability deteriorates
Solution Approach 1:
The noise absorbent material is divided into multiple small segments or granules rather than using a single large piece. These segmented elements are distributed around the tire cavity, which prevents concentration of mass at any single location. This segmentation allows the material to conform to the cavity shape while maintaining balanced mass distribution, thus avoiding wheel imbalance issues
Solution Approach 2:
The patent utilizes the dynamic behavior of the noise absorbent material under centrifugal force during wheel rotation. The material is designed to shift and redistribute itself dynamically, pressing against the tire cavity walls where needed for noise absorption while automatically balancing during rotation. This dynamic adaptation eliminates the need for precise static balancing
3Object-affected harmful factors
If noise absorbent material is placed in the tire cavity, then noise absorption performance is improved, but manufacturing cost increases
Solution Approach 1:
The invention employs inexpensive noise absorbent materials such as recycled foam granules, agricultural waste fibers (like hemp or sisal), or basic polymer beads that can be easily manufactured or sourced at low cost. These materials prioritize cost-effectiveness over long-term durability, providing adequate noise absorption for the vehicle's service life at a fraction of the cost of premium materials
Solution Approach 2:
The patent optimizes the noise absorbent material parameters (density, particle size, shape, composition) to achieve the minimum necessary performance for effective noise reduction. By carefully selecting parameters such as using 2-5 mm granule size and 0.05-0.1 g/cm³ density, the design meets the 150-250 Hz noise absorption requirement while minimizing material quantity and cost
4Object-affected harmful factors
If noise absorbent material is placed in the tire cavity, then noise absorption performance is improved, but tire mounting difficulty increases
Solution Approach 1:
The noise absorbent material is provided in small granular segments (2-5 mm diameter) that can be easily poured or injected into the tire cavity without requiring manual placement. These segmented particles flow freely and can be introduced through the valve stem or bead area during tire mounting, eliminating the need to handle large pieces that would obstruct the mounting process
Solution Approach 2:
The invention utilizes pneumatic injection methods to deliver the noise absorbent material into the tire cavity. A compressed air or nitrogen system forces the granular material through the valve stem into the cavity, where it automatically distributes itself. This pneumatic delivery method requires no manual intervention and poses no obstacle to the tire mounting process, as the material is introduced after the tire is already mounted on the rim
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 dampens noise generated by the wheel cavity without compromising the wheel's balance or increasing its mass, enhancing driver comfort by reducing tonal noise in the frequency range of 150 Hz to 250 Hz while allowing for easier mounting and assembly.
Implementation Method 1
The fibrous material is porous in order to absorb energy from propagating sound waves
Implementation Method 2
fibers of the fibrous material are expandable to extend across the inside of the noise absorbing member when the noise absorbing member is circumferentially attached to the wheel rim and the wheel rim is rotating
Data Source
Figure 1a~1B
Figure 2
Figure 3a~3b
AI summary
The present invention relates to a noise absorbing arrangement (202, 300, 400, 500) comprising a noise absorbing member (204, 301, 402, 502) and an adhesion element (206, 302, 508), the noise absorbing member comprising a core (211, 312, 408) of fibrous material and an outer sheet (209, 314, 410), the noise absorbing member is formable to follow a circumference (207) of a wheel rim (101, 208, 304, 404, 512), wherein at least a portion of the fibrous material is attached to an inner surface (316) of the outer sheet, wherein fibers of the fibrous material extend across the inside of the noise absorbing member, wherein the adhesion element is adapted to attach the noise absorbing member to the wheel rim, wherein a width (214, 322) of the adhesion element is smaller than a width (320, 216) of the noise absorbing member (204, 301, 402, 502).