Pneumatic Tire Sidewall Recesses for Air Resistance and Appearance
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Solution Overview
Problem
Pneumatic tires face challenges in reducing rolling resistance while minimizing appearance defects such as undulations on the sidewall surface, which can lead users to perceive the tire as of lower quality in terms of durability and maneuverability.
Innovation Solution
A pneumatic tire design featuring a sidewall surface with periodically varying-sized circular recesses and linear trough portions that cover the recesses, creating a serration pattern to reduce air resistance and make undulations less noticeable, with specific dimensions and arrangements to optimize air resistance reduction and aesthetic appeal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the sidewall thickness is reduced to achieve weight reduction and low rolling resistance, then weight and rolling resistance are improved, but appearance defects such as undulations become more noticeable
Solution Approach 1:
The patent applies a pattern of recesses and protrusions to the sidewall surface that creates visual distraction through geometric design. This pattern changes the optical appearance of the sidewall, making the undulations less noticeable by providing alternative visual features that draw attention away from the thickness-related defects.
2Use of energy by moving object
If recesses are provided on the sidewall surface to reduce air resistance, then air resistance is reduced, but the complexity of the sidewall surface design increases
Solution Approach 1:
The sidewall surface is segmented into multiple recesses and protrusions arranged in specific patterns. This segmentation creates turbulence-reducing features that lower air resistance while the modular nature of the segments allows for systematic design that manages complexity through repetition and standardization of the geometric elements.
Solution Approach 2:
The recesses and protrusions are arranged in periodic patterns around the sidewall circumference. This periodic arrangement creates consistent aerodynamic effects that reduce air resistance during tire rotation, while the repeating nature of the pattern provides a manageable design approach that controls complexity through regularity.
3Loss of energy
If the sidewall thickness is reduced for low rolling resistance, then rolling resistance is reduced, but the visibility of undulations increases
Solution Approach 1:
The geometric pattern of recesses and protrusions alters the visual appearance of the sidewall by creating light and shadow effects that mask the undulations. This visual masking technique reduces the perceived visibility of thickness variations without requiring increased material thickness, thus maintaining low rolling resistance.
Data Source
AI summary
A region on a sidewall surface of at least one of a pair of side portions of a pneumatic tire includes a maximum tire width position. The region is provided with a plurality of recesses shaped as dimples varying periodically in size along a tire circumferential direction, and with a plurality of trough portions shaped as lines, disposed around each of the recesses, and extending unidirectionally so as to cover the recesses. The recesses are, for example, at least three types of circular recesses, each type having a different size. Here, the circular recesses vary stepwise in size along the tire circumferential direction. The bottom face of the circular recesses is spherical. The maximum depth of the circular recesses is constant irrespective of size, being from 0.3 mm to 1.5 mm.