Tire Bead Apex Structure for Low Rolling Resistance
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Solution Overview
Problem
Existing pneumatic tires with high load capacities face challenges in balancing improved bead durability, load-bearing capacity, and reduced rolling resistance, often exacerbated by the use of reinforcing elements that increase material costs and compromise comfort.
Innovation Solution
A vehicle tire design featuring an outer apex made of a specific rubber compound with optimized mechanical properties, combined with a reinforced sidewall structure and a bead lip that provides a press fit on the rim flange, eliminates the need for additional reinforcing fabric strips while enhancing bead durability and load-bearing capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reinforcing elements such as fabric strips and additional carcass layers are used in the bead area, then bead durability and load-bearing capacity are improved, but rolling resistance increases and material costs rise
Solution Approach 1:
The invention changes the material parameters of the outer apex by specifying a Shore hardness of 55-75 and a dynamic modulus of elasticity of 8-14 N/mm², optimizing the balance between durability and rolling resistance without requiring additional reinforcing elements
Solution Approach 2:
The invention uses a composite structure with an outer apex made of rubber compound with specific properties (Shore hardness 55-75, dynamic modulus 8-14 N/mm²) that combines the benefits of stiffness for durability and controlled hysteresis for acceptable rolling resistance
2Strength
If stiffer materials and thicker padding are used in the bead area, then load-bearing capacity and robustness are improved, but comfort deteriorates
Solution Approach 1:
The invention optimizes the outer apex material parameters (Shore hardness 55-75, dynamic modulus 8-14 N/mm²) to provide sufficient stiffness for load-bearing capacity while maintaining elasticity for comfort, avoiding excessive stiffness that would deteriorate ride quality
Solution Approach 2:
The invention applies a localized outer apex with specific material properties only in the bead area where high strength is needed, while the rest of the tire maintains softer material for comfort, creating a multi-functional structure
3Reliability
If additional reinforcing elements and elaborate constructions are used, then bead durability is improved, but device complexity and material costs increase
Solution Approach 1:
The invention extracts the reinforcing function from separate fabric strips and additional carcass layers, integrating it into the outer apex itself through optimized material properties (Shore hardness 55-75, dynamic modulus 8-14 N/mm²), thereby simplifying the overall construction
Solution Approach 2:
The outer apex is designed to perform multiple functions simultaneously: providing structural support, enhancing bead durability, and controlling rolling resistance through its material properties, eliminating the need for separate reinforcing elements
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 design achieves improved rolling resistance, maintains high load-bearing capacity, and reduces material costs without compromising durability, thereby optimizing tire performance and comfort.
Implementation Method 1
an outer apex (30) made of a rubber compound with a Shore hardness A according to ASTM D 2240 of 60 to 88 and a dynamic modulus of elasticity of 8 to 12 N/mm2 and a rebound elasticity according to DIN 53512
Implementation Method 2
a rebound elasticity according to DIN 53512 of 60 to 85% at room temperature and from 65 to 90% at a temperature of 70°C
Data Source
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AI summary
The invention relates to a pneumatic tire (10) with a tread (1) and two sidewalls (6) terminating in bead areas (5), as well as a carcass (3) extending radially below the tread (1) and along the sidewalls (6) and encircling the bead areas (5), wherein the bead areas (5) comprise a core (7) and an apex (8) extending radially (rR) outwards from the core (7), and the pneumatic tire (10) is suitable for mounting on a rim (11) with a curved rim flange area (12), wherein an outer apex (30) formed from an outer apex with a Shore A hardness according to ASTM D 2240 of 60 to 88 and a dynamic modulus of elasticity of 8 to 12 N/mm² as well as a rebound elasticity according to DIN 53512 of The tire is arranged in a configuration of 60 to 85% at room temperature and 65 to 90% at a temperature of 70 °C. A vehicle wheel with such a tire is also specified.