Pneumatic Tire Bead Apex Layout for Small-Diameter Heavy Loads
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Solution Overview
Problem
Pneumatic tires with small diameters for vehicles exceeding 3 tons face reduced air volume and concentrated strain on bead portions, leading to potential damage during heavy loads.
Innovation Solution
A pneumatic tire design with a cross-sectional height to width ratio of 0.30 to 0.45 and a rim width to tire width ratio of 0.78 to 0.99, featuring bead cores with embedded bead apex rubbers positioned radially outward and carcass plies turned up around the bead cores, along with specific positioning of apex rubbers to avoid strain concentration in critical regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the tire diameter is reduced to secure wide riding space, then the vehicle can board more passengers or goods, but the air volume for supporting vehicle weight is reduced and cross-sectional height is small
Solution Approach 1:
The patent optimizes the cross-sectional height to width ratio (SH/SW) to be 0.30 to 0.45 and the rim width to tire width ratio (RW/SW) to be 0.78 to 0.99, changing geometric parameters to achieve both compact size and sufficient load-bearing capacity
2Shape
If the cross-sectional height is reduced to achieve compact tire design, then the tire fits better on small wheels, but strain is concentrated on the bead portions during heavy loads
Solution Approach 1:
The patent applies different rubber compositions to different regions: bead apex rubber with high tensile strength and elasticity for the bead portion, and outside apex rubber with different properties for the outer region, optimizing local strength where needed
Solution Approach 2:
The patent uses composite rubber materials with specific compound formulations for the bead apex rubber and outside apex rubber, combining different polymer components to achieve both compact dimensions and enhanced bead strength
3Strength
If the bead apex rubber extends too far radially outward, then it provides better support, but it positions within the first region where strain concentration causes damage
Solution Approach 1:
The patent positions the radially outer end of the bead apex rubber within 2mm of the contact area end, providing sufficient support through optimized partial coverage rather than full extension, avoiding the high-strain first region while maintaining necessary support
Data Source
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AI summary
A pneumatic tire has a bead portion provided with a bead core and a bead apex rubber. The bead apex rubber extends radially outward from the radially outer surface of the bead core, and has a radially outer end not positioned in a first region. The first region is defined between a first radial line and a second radial line. The first radial line extends straight through a radially outer end of a contact area where the bead portion comes into contact with a flange of a wheel rim. The second radial line extends straight through a position spaced 10 mm axially outward from the radially outer end of the contact area.