Pneumatic Tire Belt Structure for Durability and Rubber Separation Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional pneumatic tires face issues with tire durability due to increased stiffness in the circumferential direction leading to separation of rubber at edge portions and between contiguous belt plies, particularly in heavy-duty applications.
Innovation Solution
A pneumatic tire design featuring a belt layer with a large angle belt, cross belts of opposite signs, and a circumferential reinforcing layer with specific angle and width ratios, along with appropriate tread and tire width relationships, to enhance circumferential stiffness and distribute load uniformly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the belt layer is designed with increased circumferential stiffness to improve tire durability, then tire durability is improved, but rubber separation occurs at edge portions and between contiguous belt plies
Solution Approach 1:
The patent applies local quality by designing the belt layer with different structural characteristics in different regions. The belt plies are configured with specific belt angles (first belt ply: 10-30 degrees, second belt ply: -10 to -30 degrees) to provide circumferential stiffness where needed, while the rubber composition is specifically optimized at edge portions and between contiguous belt plies to prevent separation. This localized optimization of both structure and material properties resolves the contradiction between needing high circumferential stiffness and maintaining rubber bonding strength.
Solution Approach 2:
The patent employs composite materials by formulating a specialized rubber composition that combines multiple polymers (natural rubber, polybutadiene rubber, styrene-butadiene rubber) with specific ratios, along with sulfur, accelerators, and other additives. This composite rubber material provides both the flexibility needed to prevent separation and the bonding strength to maintain integrity under the high circumferential stiffness conditions created by the belt layer structure.
2Force
If the belt angle is increased to enhance circumferential reinforcing effect, then stiffness in tire circumferential direction is improved, but radial growth difference between center and shoulder regions increases
Solution Approach 1:
The patent applies asymmetry by using belt plies with opposite sign belt angles. The first belt ply has a positive belt angle (10-30 degrees) while the second belt ply has a negative belt angle (-10 to -30 degrees). This asymmetric configuration creates a balanced reinforcing effect that provides circumferential stiffness while compensating for radial growth differences between the center and shoulder regions, thus resolving the contradiction.
Solution Approach 2:
The patent addresses the radial growth issue by introducing the belt angle dimension as a critical parameter. By carefully controlling the belt angles of the first and second belt plies to be within specific ranges and having opposite signs, the design utilizes this angular dimension to simultaneously achieve circumferential stiffness and radial growth uniformity, effectively resolving the contradiction between these two requirements.
3Reliability
If the width of circumferential reinforcing layer is increased to improve durability, then tire durability is improved, but manufacturing complexity and material usage increase
Solution Approach 1:
The patent applies parameter changes by optimizing the width of the circumferential reinforcing layer within a specific range (0.60≤Ws/Wca≤0.70) rather than simply maximizing it. This parameter optimization ensures sufficient durability while avoiding excessive material usage and manufacturing complexity. The specific width ratio provides the right balance between performance and practical constraints.
Data Source
AI summary
A pneumatic tire comprises a carcass layer, a belt layer radially outward of the carcass layer, and a tread rubber radially outward of the belt layer. The belt layer is formed by laminating a large angle belt having a belt-cord angle of 45°-70°, a pair of cross belts having belt cord angles of 10°-45° with opposite sign belt cord angles, and a reinforcing layer having a belt cord angle satisfying ±5° relative to a circumferential direction. A reinforcing layer width Ws and a carcass cross-sectional width Wca satisfy 0.60≤Ws/Wca≤0.70. A wider cross belt width Wb2 of the pair of cross belts and the carcass width Wca satisfy 0.79≤Wb2/Wca≤0.89. Relationships 0.79≤Wb2/Wca≤0.84 and either 0.82≤TW/Wca≤0.92 or 0.79≤TW/SW≤0.89 are satisfied, where TW is a tread width and SW is a total tire width.