Passenger Tire Sidewall Composition for Low Rolling Resistance
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Solution Overview
Problem
Existing passenger vehicle tires face a challenge in reducing rolling resistance without degrading handling performance and incurring significant manufacturing costs.
Innovation Solution
A passenger vehicle tire design with specific elastomeric mixtures in lower zones and sidewall layers, featuring low hysteresis and controlled shear stiffness, maintains transverse drift rigidity while optimizing rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If elastomeric mixtures with low hysteresis are used in lower zones to reduce rolling resistance, then rolling resistance performance is improved, but transverse drift rigidity may be degraded
Solution Approach 1:
The patent applies different elastomeric mixtures with different hysteresis characteristics to different zones of the tire. Low hysteresis mixtures (Tan δ ≤ 0.10) are used specifically in the lower zones (beads and sidewalls) to reduce rolling resistance, while the crown and tread areas use conventional mixtures to maintain transverse drift rigidity and handling performance. This spatial differentiation of material properties resolves the contradiction between reducing energy loss and maintaining structural strength.
Solution Approach 2:
The tire is segmented into distinct functional zones (lower zones including beads and sidewalls versus crown and tread) with different elastomeric composition requirements. The lower zones are specifically targeted for low hysteresis materials to minimize rolling resistance, while other zones maintain conventional compositions for handling. This segmentation allows independent optimization of each zone's material properties to address the contradictory requirements.
2Loss of energy
If elastomeric mixtures with low hysteresis and controlled shear stiffness are used, then rolling resistance is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent specifies precise compositional requirements (Tan δ ≤ 0.10, specific shear modulus ranges) for elastomeric mixtures used in lower zones. This local quality specification allows manufacturers to target material optimization only where it provides maximum benefit (lower zones), rather than requiring complex multi-material construction throughout the entire tire, thereby limiting manufacturing complexity while achieving rolling resistance reduction.
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 tire achieves a balance between improved rolling resistance and handling performance without substantial manufacturing cost increases, utilizing elastomeric mixtures with low hysteresis and controlled shear stiffness in lower zones and sidewall layers.
Implementation Method 1
The bead of each lower zone comprises at least one filling layer comprised at least in part between the main part of the carcass reinforcement, the upturn of the carcass reinforcement and the radially outer portion of the annular reinforcement structure; the elastomeric mixtures having an elastic modulus of shear stiffness and a viscoelastic loss measured according to standard ASTM D 5992-96, at 23°C, under a shear strain equal to 10%
Implementation Method 2
the elastomeric mixtures having an elastic modulus of shear stiffness and a viscoelastic loss measured according to standard ASTM D 5992-96, at 23°C, under a shear strain equal to 10%
Data Source
Figure 1A~2D
Figure 3~4B
AI summary
The invention relates to a tyre (1) for a passenger vehicle, the performance of which in terms of rolling resistance has been improved without compromising transverse drift rigidity. The bead (50) is softened by the use of low-hysteresis materials. The transverse drift rigidity is compensated by virtue of the use of a rigid and low-hysteresis sidewall layer (30). The layers of compounds in the bottom region having a viscoelastic loss Tan(δ)max of less than or equal to 0.10 represent a volume of between 30% and 90% of the total volume of the bottom region, and the shear stiffness elastic modulus G'(M3) of the sidewall layer lies in the range [0.5; 10].