Single-Ply Tire Structure for High-Load Durability and Low Rolling Resistance
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Solution Overview
Problem
Existing tires face a challenge in achieving improved durability without increasing rolling resistance, particularly for high-load capacity tires used in electric vehicles, as reducing the number of carcass plies to decrease mass can compromise stiffness, and reinforcing the tire for durability often leads to increased mass and rolling resistance.
Innovation Solution
A tire design with a single carcass ply, including a specific thickness ratio of carcass portions and optimized sidewall layer thickness, along with a balanced belt width, to maintain stiffness and durability while minimizing rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the number of carcass plies is reduced to decrease tire mass, then rolling resistance is reduced, but the stiffness of the tire decreases
Solution Approach 1:
The patent applies local quality by varying the thickness of the carcass ply in different regions of the tire. The carcass ply is designed with a first thickness in the circumferential direction at the equatorial region and a second thickness at the diagonal regions, creating local thickness variations that optimize both stiffness and mass. This regional differentiation allows the tire to maintain necessary stiffness where needed while reducing mass in other areas, thereby reducing rolling resistance without compromising overall structural integrity.
Solution Approach 2:
The patent employs parameter changes by specifically controlling the thickness ratio between different regions of the carcass ply. The first thickness in the circumferential direction is set to be greater than the second thickness in the diagonal direction, creating a controlled parameter variation that enhances stiffness in critical areas while reducing mass overall. This parameter optimization resolves the contradiction between mass reduction and stiffness maintenance.
2Reliability
If the tire is reinforced by incorporation of new elements to improve durability, then durability is improved, but the mass of the tire is increased
Solution Approach 1:
The patent applies local quality by concentrating reinforcement in specific regions where it is most needed. The carcass ply is designed with increased thickness in the circumferential direction at the equatorial region, which is the area subject to highest stresses during operation. This localized reinforcement improves durability in critical areas without adding unnecessary mass throughout the entire tire structure, thereby resolving the contradiction between durability enhancement and mass control.
Solution Approach 2:
The patent utilizes composite material principles by combining the carcass ply with the belt structure. The belt, positioned radially outward from the carcass ply, works in conjunction with the optimized carcass ply to provide enhanced durability. This composite approach allows the tire to achieve high durability through the synergistic effect of multiple layers with different functional properties, rather than simply adding mass throughout the entire structure.
3Weight of moving object
If the lengths of turned-up portions of the carcass plies are shortened to reduce mass, then tire mass is reduced, but the stiffness of the tire decreases
Solution Approach 1:
The patent applies local quality by differentiating the thickness of the carcass ply in different regions. The turned-up portions are designed with a first thickness in the circumferential direction that is greater than the second thickness in the diagonal direction. This local thickness variation maintains the necessary stiffness in the circumferential direction where the turned-up portions contribute to structural integrity, while allowing mass reduction in other areas. The controlled thickness distribution ensures that stiffness is preserved despite shortened turned-up portions.
Solution Approach 2:
The patent employs parameter changes by optimizing the thickness parameters of the carcass ply in different regions. The first thickness in the circumferential direction is specifically set to be greater than the second thickness, creating a controlled parameter variation that maintains stiffness where needed. This parameter optimization allows the turned-up portions to be shortened for mass reduction while preserving the necessary stiffness through the controlled thickness ratio.
Data Source
AI summary
A tire can include beads, a carcass, sidewall layers, a tread, a belt, and a band. A carcass ply of the carcass can include a ply body and a pair of turned-up portions. An end of each turned-up portion can be located axially inward of an end of the belt. A ratio of a thickness from the carcass to an outer surface of the tire along a first normal line to a thickness from the carcass to the outer surface of the tire along a second normal line can be not less than 1 and not greater than 2.