Segmented Tire Tread Shoulder Grooves for Aerodynamic Drag Reduction
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Solution Overview
Problem
Existing tire treads with decoupling or narrow circumferential grooves reduce rolling resistance but increase aerodynamic drag, leading to unfavorable fuel consumption.
Innovation Solution
A tread design featuring a plurality of lateral grooves and at least one narrow circumferential groove at the shoulder region, divided into segments with specific geometric configurations to enhance aerodynamics, including a segment center positioned axially outward from the contact patch to prevent air flow separation and maintain noise performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a narrow circumferential groove is provided at the shoulder region of the tread, then rolling resistance is reduced due to better tread deformation, but aerodynamic drag increases due to continuous edge creation and air flow separation
Solution Approach 1:
The narrow circumferential groove is divided into multiple segments along the circumferential direction, creating discrete groove portions rather than a continuous groove. This segmentation eliminates the continuous edge that causes air flow separation, thereby reducing aerodynamic drag while maintaining the rolling resistance benefits through localized tread deformation capability.
Solution Approach 2:
The groove segments are positioned asymmetrically with respect to the tire's rotational axis and contact patch, with specific segments located at defined distances from the contact patch center. This asymmetric arrangement optimizes both the tread deformation for rolling resistance and the aerodynamic profile by avoiding symmetric continuous edges.
2Object-generated harmful factors
If the segment center is positioned axially outward from the contact patch with distance d ≤ 5mm, then aerodynamic flow separation is prevented, but the groove must be precisely positioned to maintain noise performance
Solution Approach 1:
The invention specifies precise parameter ranges for groove segment positioning, including the distance d from the contact patch center (d ≤ 5mm) and the angle α (5° ≤ α ≤ 25°). By defining these parameters within specific ranges, the invention balances aerodynamic performance with manufacturing feasibility, allowing sufficient tolerance while maintaining effectiveness.
Data Source
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AI summary
The present invention provides a tread for a tire having a contact face intended to come into contact with ground during rolling, provided with a plurality of lateral grooves (3) extending generally axial orientation and at least one narrow circumferential groove (4) at a shoulder region of the tread, the narrow circumferential groove (4) being divided into a plurality of segments (5, 51, 52), each the segment having two ends, a first segment end and a second segment end being distant in circumferential orientation, a segment center at a center along the segment, a length L along the segment and a width E, the segment center being axially outward from an axially outermost of a contact patch (6) with a distance d when a tire with the tread being mounted onto its nominal rim, inflated to 180 kPa and 75% of nominal load being applied, a virtual straight line connecting the two ends of each the segment has an angle a greater than or equal to 5° and smaller than or equal to 25° with respect to the circumferential orientation, and the distance d is smaller than or equal to 5 mm.