Low-Aspect-Ratio Tire Belt Structure for Edge Separation Control
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Solution Overview
Problem
Off-road tires with low aspect ratios experience increased load index and deflection, leading to separation of peripheral rubber at belt edges due to higher load capacity demands.
Innovation Solution
A pneumatic tire design featuring a carcass layer with a cord angle of 80° to 100°, a belt layer with a first and second reinforcing belt, and an auxiliary belt with a cord angle of 55° to 70°, positioned between the carcass layer and the first reinforcing belt, to enhance belt edge durability and reduce radial growth in the shoulder region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the aspect ratio of the tire is lowered to improve load capacity, then the applied load capacity is improved, but the load index increases causing increased deflection amount and peripheral rubber separation at belt edges
Solution Approach 1:
The belt layer is segmented into multiple reinforcing belts with different cord angles and widths. The first reinforcing belt has cords at 10°-25° with width extending to the tire equatorial plane, while the second reinforcing belt has cords at 35°-50° and is narrower, positioned to overlap with the first belt. This segmentation allows each belt to perform specific functions: the first belt provides radial strength for load capacity, while the second belt controls shoulder region deformation and prevents peripheral rubber separation.
Solution Approach 2:
Different regions of the tire structure are given different cord angles and material properties to address local requirements. The carcass layer uses cords at 85°-95° for radial flexibility, the first reinforcing belt uses 10°-25° cords for load bearing, and the second reinforcing belt uses 35°-50° cords for edge stability. This local differentiation of structural properties resolves the contradiction between overall load capacity and local belt edge durability.
2Length of stationary object
If the aspect ratio is lowered to maintain tire outer diameter, then the applied load capacity is improved, but the deflection amount increases leading to separation of peripheral rubber
Solution Approach 1:
The belt layer is divided into multiple reinforcing belts with different cord angles and widths. The first reinforcing belt has cords at 10°-25° with width extending to the tire equatorial plane, while the second reinforcing belt has cords at 35°-50° and is narrower, positioned to overlap with the first belt. This segmentation allows each belt to perform specific functions: the first belt provides radial strength for load capacity, while the second belt controls shoulder region deformation and prevents peripheral rubber separation.
Solution Approach 2:
The invention changes the cord angle parameter of the reinforcing belts to control deflection characteristics. By using cords at specific angles (10°-25° for the first belt, 35°-50° for the second belt), the tire maintains appropriate stiffness to control deflection amount while preserving the outer diameter, thus resolving the contradiction between maintaining diameter and controlling deflection-induced separation.
3Reliability
If an auxiliary belt is added between the carcass layer and the first reinforcing belt, then the belt edge durability is improved, but the device complexity increases
Solution Approach 1:
The belt layer is segmented into multiple reinforcing belts with different cord angles and widths. The first reinforcing belt has cords at 10°-25° with width extending to the tire equatorial plane, while the second reinforcing belt has cords at 35°-50° and is narrower, positioned to overlap with the first belt. This segmentation allows each belt to perform specific functions: the first belt provides radial strength for load capacity, while the second belt controls shoulder region deformation and prevents peripheral rubber separation.
Solution Approach 2:
Different regions of the tire structure are given different cord angles and material properties to address local requirements. The carcass layer uses cords at 85°-95° for radial flexibility, the first reinforcing belt uses 10°-25° cords for load bearing, and the second reinforcing belt uses 35°-50° cords for edge stability. This local differentiation of structural properties resolves the contradiction between overall load capacity and local belt edge durability.
Data Source
AI summary
The pneumatic tire (1) includes a carcass layer (13), a belt layer (14) disposed on an outer side of the carcass layer (13) in a radial direction, and a tread rubber disposed on an outer side of the belt layer (14) in the radial direction. Additionally, the carcass layer (13) has a cord angle of 80° or more and 100° or less. Additionally, the belt layer (14) is formed by layering a first reinforcing belt (141), a second reinforcing belt (142) that is narrower than the first reinforcing belt (141), and an auxiliary belt (145) that is spaced apart from a tire equatorial plane (CL) and disposed between the carcass layer (13) and the first reinforcing belt (141). Additionally, the first reinforcing belt (141) and the second reinforcing belt (142) have cord angles of 11° or more and 30° or less, and the auxiliary belt has a cord angle of 55° or more and 70° or less.