Tire Sidewall and Bead Layout for Low Rolling Resistance
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Solution Overview
Problem
Current tires face a challenge in reducing rolling resistance without compromising handling performance and increasing manufacturing costs, as existing solutions either complicate industrial processing or incur significant cost increases.
Innovation Solution
The tire design incorporates two lower regions with elastomer compounds having a viscoelastic loss Tan(δ)max less than or equal to 0.10, occupying 30% to 90% of the volume, and an elastic shear modulus of 0.5 to 10 MPa for the sidewall layer, along with a balanced architecture that maintains handling capabilities without major process changes or cost increments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If elastomer compounds with low viscoelastic loss are used in the lower regions, then rolling resistance is reduced, but transverse slip stiffness may be compromised
Solution Approach 1:
The patent applies different elastomer compound properties to different regions of the tire. The lower regions (beads and sidewalls) use compounds with low viscoelastic loss (Tan(δ)max ≤ 0.10) to reduce rolling resistance, while the crown region maintains compounds with higher transverse slip stiffness for handling performance. This spatial differentiation of material properties resolves the contradiction between energy loss and structural strength.
Solution Approach 2:
The tire is divided into distinct functional segments: lower regions (beads and sidewalls) optimized for low rolling resistance, and crown regions optimized for transverse slip stiffness. The lower regions specifically include beads with filler layers and sidewalls with elastomer compounds having Tan(δ)max ≤ 0.10, while crown layers maintain different properties. This segmentation allows each region to independently optimize its performance characteristics.
2Loss of energy
If complex bead structures are implemented to reduce rolling resistance, then energy loss is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent reduces rolling resistance by changing the viscoelastic parameters of the elastomer compounds in the lower regions rather than implementing complex structural modifications. Specifically, it specifies compounds with Tan(δ)max ≤ 0.10 at 100°C and 10 Hz, and controls elastic shear modulus in the range 0.5-10 MPa for sidewall layers. These parameter changes achieve energy loss reduction while maintaining relatively simple manufacturing processes.
3Strength
If sidewall layer stiffness is increased to improve handling, then transverse slip stiffness is improved, but rolling resistance increases
Solution Approach 1:
The patent applies different elastomer compound properties to different regions of the tire. The lower regions (beads and sidewalls) use compounds with low viscoelastic loss (Tan(δ)max ≤ 0.10) to reduce rolling resistance, while the crown region maintains compounds with higher transverse slip stiffness for handling performance. This spatial differentiation of material properties resolves the contradiction between energy loss and structural strength.
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 effectively reduces rolling resistance while maintaining appropriate transverse slip stiffness and handling performance, keeping industrial manufacturing costs normal by optimizing elastomer compound properties and architecture.
Implementation Method 1
The elastomer compounds having an elastic shear modulus and a viscoelastic loss measured in accordance with ASTM D 5992-96, at 23° C., under a shear strain of 10%; said layers of compounds in each lower region having a viscoelastic loss Tan(δ)max less than or equal to 0.10
Implementation Method 2
The elastomer compounds having an elastic shear modulus and a viscoelastic loss measured in accordance with ASTM D 5992-96, at 23° C., under a shear strain of 10%; said layers of compounds in each lower region having a viscoelastic loss Tan(δ)max less than or equal to 0.10
Implementation Method 3
The elastic shear modulus of each sidewall layer is in the range [0.5; 10] MPa
Data Source
AI summary
The invention relates to a tyre (1) for a passenger vehicle of which the performance in terms of rolling resistance has been improved without adversely affecting the transverse slip stiffness. The bead (50) is made more flexible by the use of low-hysteresis materials. The transverse slip stiffness is compensated for through the use of a rigid, low-hysteresis sidewall layer (30). The layers of compounds of the lower region having a viscoelastic loss Tan(δ)max less than or equal to 0.10 represent a volume of between 30% and 90% of the total volume of said lower region, and the elastic shear modulus G′ (M3) of each sidewall layer is in the range [0.5; 10] MPa.