Pneumatic Tire Noise Damping via Porous Sponge Protrusions
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Solution Overview
Problem
Current pneumatic tires do not adequately reduce road noise, particularly due to resonance vibrations of air in the tire cavity, despite existing solutions like sponge members on the tread inner surface or sound-absorbing belts.
Innovation Solution
Incorporating a belt layer with sponge members arranged in the tire circumferential direction, featuring alternating protrusions and recesses, and a specific volume distribution to effectively absorb sound energy and reduce resonance vibrations, while ensuring proper mounting and minimizing mass increase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If sponge members are added to the tread inner surface to reduce road noise, then road noise is reduced, but the structure becomes more complex and mass increases
Solution Approach 1:
The patent uses sponge members with porous structures placed on the tread inner surface to absorb sound energy from resonance vibrations in the tire cavity. The porous material converts acoustic energy into thermal energy through viscous dissipation in the pores, effectively reducing road noise while maintaining a relatively simple overall structure.
Solution Approach 2:
The invention combines sponge members with the existing tire structure (tread, belt layer, carcass) to create a composite noise reduction system. The sponge members are integrated with the belt layer and tread inner surface, forming a multi-layer composite structure that maintains structural integrity while adding noise reduction functionality.
2Object-affected harmful factors
If sponge members are added to reduce road noise, then road noise is reduced, but the mass of the tire increases
Solution Approach 1:
The sponge members are made from lightweight porous materials that provide effective sound absorption per unit mass. The porous structure allows for high surface area to volume ratio, improving noise reduction efficiency while keeping the material density low and overall mass increase minimal.
3Object-affected harmful factors
If the axial width of sponge members is increased to improve noise reduction, then sound absorption increases, but the space for other tire components is reduced
Solution Approach 1:
The sponge members are strategically positioned on the tread inner surface at locations where resonance vibrations are most intense. The axial width of each sponge member is optimized to cover the critical noise-generating areas while leaving other regions of the tire cavity open for proper air circulation and structural requirements. The width is set between 19% to 90% of the belt layer width to achieve local noise reduction without compromising overall tire performance.
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 significantly reduces road noise by increasing the surface area for sound absorption and optimizing the arrangement and volume of sponge members within the tire cavity, enhancing both noise reduction and vibration suppression.
Implementation Method 1
A primary cause of the road noise is resonance vibrations of air generated in the tire cavity. To reduce such resonance vibrations of air, JP 3622957 B2, EP 1 253 025 A1 and JP 2006-182280 A have each proposed a pneumatic tire which includes a tread portion provided with a sponge member on a tread inner surface.
Data Source
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AI summary
The present invention is directed to a pneumatic tire which includes a tread portion having a tread inner surface provided with a noise damper. The noise damper includes sponge members arranged in a tire circumferential direction. Each sponge member includes an inner surface facing radially inwardly, wherein the inner surface of each sponge member includes protrusions protruding radially inward and recesses recessed radially outward, and the protrusions and the recesses are arranged alternately.