Pneumatic Tire Protrusion Noise Reduction
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Solution Overview
Problem
Pneumatic tires generate excessive pass-by noise due to turbulence in air flow, leading to significant air pressure fluctuations along vehicle side surfaces, which increases external noise levels.
Innovation Solution
The pneumatic tire features protrusion portions on its side surfaces that extend in a direction intersecting both the tire's circumferential and radial directions, with an intermediate portion having the highest projection height positioned within 20% of the tire's cross-sectional height from the maximum width, and end portions with lower projection heights, causing air turbulence to minimize low-velocity air flow and subdividing vortices, thereby reducing air pressure changes and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If protrusion portions are provided on tire side portions to reduce air resistance, then air resistance reduction effect is obtained, but pass-by noise becomes excessively large due to air pressure fluctuations
Solution Approach 1:
The protrusion portions are designed with non-uniform projection heights along the tire circumferential direction, creating local variations in air flow disruption. This local quality variation allows the tire to generate turbulence in specific regions to reduce overall air resistance while controlling noise generation in other regions.
Solution Approach 2:
The protrusion portions are configured with asymmetric characteristics, including inclined extension directions and varying projection heights. This asymmetry creates controlled turbulence patterns that reduce air resistance while the specific geometric configuration helps manage the resulting noise levels.
2Loss of energy
If protrusion portions extend in elongated manner between inner and outer sides to reduce air resistance, then uniformity is improved, but air pressure fluctuation increases causing noise
Solution Approach 1:
The protrusion portions are segmented into multiple discrete elements distributed around the tire circumference, with each portion having a specific projection height and orientation. This segmentation allows control over air flow disruption patterns, creating turbulence for drag reduction while limiting pressure fluctuations through proper spacing and sizing.
Solution Approach 2:
The projection height of the protrusion portions is specifically controlled to be 5 mm or less, and their extension directions are inclined at specific angles relative to the tire radial direction. These parameter changes optimize the balance between generating sufficient turbulence for air resistance reduction and limiting pressure fluctuations that cause noise.
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
This design significantly reduces pass-by noise by minimizing low-velocity air flow and subdividing vortices, improving air flow rectification along the vehicle's side surfaces, resulting in lower noise levels and enhanced ride comfort.
Implementation Method 1
the protrusion portions that rotate cause air around the protrusion portions to be turbulent and minimize air flow having low velocity
Implementation Method 2
a vortex generated from the tire housing on the rear side of the pneumatic tire in the advancement direction is subdivided
Data Source
AI summary
A pneumatic tire includes a plurality of protrusion portions extending along a tire side surface of a tire side portion in a direction that intersects a tire circumferential direction and a tire radial direction. Each of the plurality of protrusion portions includes an intermediate portion and an end portion. The intermediate portion in an extension direction has a highest position of a projection height from the tire side surface. The end portion is provided on either end of the intermediate portion in the extension direction, and has a lowest position of the projection height from the tire side surface. The highest position of the projection height of the intermediate portion is disposed in a range of 20% of a tire cross-sectional height on an inner side and an outer side in the tire radial direction from a tire maximum width position.