Heavy Load Tire Radius Growth Control
Solution Overview
Problem
Conventional pneumatic tires for heavy loads with wide bases and low aspect ratios suffer from uneven radius growth, leading to reduced durability, resistance to wire fatigue, and uneven wear, despite attempts to address these issues through various design modifications.
Innovation Solution
A pneumatic tire design featuring at least two crossing belts angled between 10 and 30 degrees and a circumferential reinforcement layer angled between zero and five degrees, with a specific force distribution and geometry to limit radius growth to less than 0.3% at the crown center and circumferentially-formed grooves, enhancing the tire's rigidity and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a pneumatic tire for heavy load has a wide base and low aspect ratio (aspect ratio ≤ 70%), then the tire can support heavy loads and provide stable performance, but uneven radius growth occurs in the shoulder part leading to reduced durability and wire fatigue resistance
Solution Approach 1:
The patent applies local quality by varying the belt layer configuration in different regions of the tire. Specifically, the first and second belt layers have different widths, with the first belt layer extending further in the tire width direction than the second belt layer. This creates localized reinforcement in the shoulder region where radius growth is most problematic, while maintaining appropriate flexibility in other areas. The differentially configured belt layers provide targeted structural support to prevent uneven deformation without compromising overall tire performance.
2Strength
If the belt layers are made wider to improve load distribution, then the tire can better support heavy loads, but the radius growth becomes more uneven causing increased wear and reduced durability
Solution Approach 1:
The patent employs asymmetry by configuring the first and second belt layers with different widths and extensions. The first belt layer has a greater width and extends further into the shoulder region compared to the second belt layer. This asymmetric arrangement creates a deliberate imbalance in the belt structure that compensates for the natural tendency toward uneven radius growth in wide-base, low aspect ratio tires. The asymmetric design allows differential stiffness distribution across the tire width, controlling deformation patterns to achieve more uniform radius growth.
3Stability of the object's composition
If the aspect ratio is reduced to provide a wider base for heavy load support, then the tire stability improves, but the radius growth at the crown center and shoulder increases leading to uneven wear
Solution Approach 1:
The patent applies parameter changes by modifying the geometric parameters of the belt layers, specifically the width and extension distance of the first and second belt layers. By adjusting these dimensional parameters, the patent optimizes the stiffness distribution across the tire structure. The first belt layer is configured with specific width and extension parameters that provide enhanced radial support in critical areas, while the second belt layer has different parameters that balance the overall structure. These parameter adjustments control the deformation characteristics under load, limiting excessive radius growth at the crown center and shoulder regions.
Data Source
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AI summary
In a pneumatic tire for heavy load (1) including a circumferentially-formed groove (22) running in a circumferential direction of the tire on a surface of a tread part (2), when a pneumatic pressure equivalent to a normal inner pressure is applied with reference to a case where a pneumatic pressure equivalent to an inner pressure of 100 kPa is applied, a radius growth in a radial direction of the tire at a crown center (CL) of the tread part (2) and in the circumferentially-formed groove (22) located at the most lateral side in a width direction of the tire is made to be less than 0.3%. For example, at least two crossing belts (72, 74) arranged at an angle not less than 10 degrees and not more than 30 degrees with respect to the circumferential direction of the tire, and at least one circumferential reinforcement layer (73) arranged at an angle not less than zero degree and not more than five degrees with respect to the circumferential direction of the tire are provided at an outer side of a carcass layer (6) in the radial direction of the tire.