Two-Ply Pneumatic Tire Carcass for Sidewall Stability and Lower Weight
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Solution Overview
Problem
Conventional pneumatic vehicle tires, particularly those for vans and commercial vehicles, face challenges in achieving a balance between sidewall stability, resistance to pressure deformation, weight, rolling resistance, and manufacturing efficiency, with existing designs like C+0 and 1+3/4 constructions being either too weak or excessively heavy.
Innovation Solution
A tire carcass design combining a C-carcass ply with a pronounced ply turn-up and a second, greatly shortened carcass ply arranged largely below the tread, optimized with specific arrangements and materials to enhance sidewall robustness and reduce weight, while allowing adaptation to different load scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a single C-layer carcass is used, then weight is reduced and rolling resistance decreases, but sidewall stability and resistance to pressure deformation are insufficient
Solution Approach 1:
The carcass is divided into two separate plies (first and second carcass plies) with different functions: the first ply provides basic structural support with turn-ups at sidewalls, while the second ply is positioned primarily in the tread area to reinforce against pressure deformation. This segmentation allows each ply to be optimized for its specific function, achieving both weight reduction and improved strength.
Solution Approach 2:
The second carcass ply is strategically positioned to extend predominantly in the tread area (90% or more of its width) rather than uniformly throughout the tire. This local concentration of reinforcement provides enhanced resistance to pressure deformation where it is most needed, while minimizing additional weight in areas where it is less critical.
2Strength
If additional belt layers are added between tread and carcass, then resistance to pressure deformation improves, but overall weight increases and rolling resistance worsens
Solution Approach 1:
The function of resisting pressure deformation is extracted from the traditional belt layer location and instead integrated into the second carcass ply positioned in the tread area. This eliminates the need for additional heavy belt layers while achieving the same protective function, thereby reducing overall weight and rolling resistance.
3Strength
If a 1+3/4 construction is used, then sidewall robustness is improved, but weight and rolling resistance increase significantly
Solution Approach 1:
The second carcass ply is positioned to extend predominantly in the tread area (90% or more of its width) rather than uniformly throughout the tire. This local concentration of reinforcement provides enhanced resistance to pressure deformation where it is most needed, while minimizing additional weight in areas where it is less critical.
4Weight of moving object
If C+0 construction is used, then weight is reduced, but resistance to mechanical damage in tread area is insufficient
Solution Approach 1:
The carcass is divided into two separate plies with different functions: the first ply provides basic structural support with turn-ups at sidewalls, while the second ply is positioned primarily in the tread area to reinforce against pressure deformation. This segmentation allows each ply to be optimized for its specific function.
Solution Approach 2:
The second carcass ply is strategically positioned to extend predominantly in the tread area (90% or more of its width) rather than uniformly throughout the tire. This local concentration of reinforcement provides enhanced resistance to pressure deformation where it is most needed, while minimizing additional weight in areas where it is less critical.
Data Source
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AI summary
The invention relates to a vehicle pneumatic tire (10) comprising: a) a tire carcass with a first bead element (12) and a second bead element, comprising a first carcass ply (14) and a second carcass ply (16), b) an inner tire layer (18) located radially inside the tire carcass relative to the tire carcass, and c) a tread (20) located radially outside the tire carcass relative to the tire carcass with a contact area (21) provided for road contact, wherein the first carcass ply (14) has a central part extending between the first bead element (12) and the second bead element, as well as a first ply overlay (22) around the first bead element (12) and a second ply overlay around the second bead element, wherein the end of the first ply overlay (22) and the end of the second ply overlay are arranged such thatthat the first ply (22) and the second ply are arranged section by section between the central part and the contact area (21) of the tread (20), wherein the second carcass ply (16) is arranged to 90% or more between the inner tire layer (18) and the contact area (21) of the tread (20), based on the width of the second carcass ply (16) transverse to the circumferential direction.