Segmented Tread Cap Rubber for Tyre Rolling Resistance
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Solution Overview
Problem
Existing pneumatic vehicle tires face a conflict between achieving low rolling resistance and high cornering stiffness, as a single rubber mixture in the tread cap cannot optimize both properties simultaneously.
Innovation Solution
The tire features two side sections with a rubber mixture having a lower dynamic modulus of elasticity and higher rebound elasticity, while the central section has a higher dynamic modulus of elasticity, optimizing rolling resistance and cornering stiffness by distributing these properties across different sections of the tread.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single rubber mixture is used in the tread cap, then the structure is simple and manufacturing is easier, but it cannot simultaneously optimize both low rolling resistance and high cornering stiffness
Solution Approach 1:
The tread cap is segmented into three distinct sections (central section and two side sections) with different rubber mixtures. The central section uses a rubber mixture optimized for cornering stiffness with higher dynamic modulus of elasticity, while the side sections use a rubber mixture optimized for rolling resistance with lower dynamic modulus of elasticity and higher rebound elasticity. This segmentation allows each section to independently optimize its specific function without compromising the other sections' performance.
Solution Approach 2:
Different regions of the tread cap are assigned different material properties tailored to their specific functional requirements. The central section, which primarily handles cornering forces, receives a stiffer rubber compound for high lateral stiffness. The side sections, which contribute more to rolling resistance, receive a more compliant compound with higher rebound elasticity. This local differentiation of material quality enables simultaneous optimization of conflicting properties in different locations.
2Strength
If a rubber mixture with high dynamic modulus of elasticity is used in the central section, then cornering stiffness is improved, but rolling resistance increases
Solution Approach 1:
The tread is divided into functional zones where the central section uses high E' rubber for cornering stiffness while side sections use low E' high rebound rubber for rolling resistance reduction, allowing both properties to be optimized in their respective locations simultaneously
Solution Approach 2:
The central section is specifically engineered with high dynamic modulus of elasticity rubber compound to maximize cornering stiffness where lateral forces are greatest, while this property is deliberately reduced in side sections to minimize energy loss during rolling
3Loss of energy
If a rubber mixture with high rebound elasticity is used in the side sections, then rolling resistance is reduced, but cornering stiffness decreases
Solution Approach 1:
The tread cap is divided into central and side sections with different rubber compounds. The side sections use high rebound elasticity material to minimize energy loss during rolling, while the central section uses high E' material for cornering stiffness, allowing each property to be optimized where it matters most
Solution Approach 2:
High rebound elasticity rubber is applied locally to the side sections where it can effectively reduce rolling resistance without compromising the cornering stiffness provided by the high E' rubber in the central section that bears the brunt of lateral cornering forces
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 results in a tire with improved rolling resistance and cornering stiffness, maintaining balanced tread properties without negatively affecting abrasion resistance, achieved by selecting rubber mixtures for the central and side sections based on dynamic modulus and rebound elasticity values.
Implementation Method 1
a higher rebound elasticity at 70 °C according to DIN 53512 has as the central section of the tread cap
Implementation Method 2
a rubber mixture which has a lower dynamic modulus of elasticity E' and at 55 °C according to DIN 53513 (at 8% elongation) than the central section
Data Source
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AI summary
The invention relates to a vehicle pneumatic tire with a radial carcass, a multi-layer belt (2), and a tread (1), which in the radial direction is composed of two layers made of different rubber compounds: a tread cap (7) and a tread base (8). The tread cap (7), viewed in the axial direction, has a central section (7a) and two lateral sections (7b). The two lateral sections (7b) consist of a rubber compound that has a lower dynamic modulus of elasticity Eʹ at 55°C according to DIN 53513 (at 8% elongation) and a higher rebound elasticity at 70°C according to DIN 53512 than the central section (7a) of the tread cap (7).