Triple-Layer Carcass Tire with Variable Cord Angles
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Solution Overview
Problem
Existing pneumatic tire designs face challenges in reducing weight while maintaining rigidity and durability, particularly in the tread and side regions, with conventional methods either compromising on reinforcement or employing complex manufacturing processes.
Innovation Solution
A pneumatic tire with a curved carcass structure featuring a triple layer carcass layer where the cord angle changes continuously in the tread and side regions, combined with a single belt layer and an intermediate rubber layer, to achieve desired rigidity and weight reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the thickness of rubber used for cap tread and sides is reduced to decrease tire weight, then weight is reduced, but wear resistance and durability deteriorate
Solution Approach 1:
The carcass layer is divided into three distinct sub-layers (first, second, and third sub-layers) with different cord angle configurations. The first and third sub-layers have smaller cord angles (15-45 degrees) for tread region reinforcement, while the second sub-layer has larger cord angles (75-85 degrees) for side region reinforcement. This segmentation allows each sub-layer to specialize in reinforcing specific regions, enabling weight reduction while maintaining durability through optimized local reinforcement.
Solution Approach 2:
Different sub-layers of the carcass layer provide different reinforcement characteristics in different regions. The first sub-layer primarily reinforces the tread region with smaller cord angles, the second sub-layer primarily reinforces the side region with larger cord angles, and the third sub-layer provides additional tread region reinforcement. This local quality differentiation ensures that reinforcement is concentrated where needed, allowing overall weight reduction without compromising regional durability.
2Strength
If two or more carcass layers are used to reinforce the space between bead cores, then reinforcement is improved, but manufacturing complexity increases and effective reinforcement is reduced due to non-functional end portions
Solution Approach 1:
The patent combines the reinforcement functions of multiple traditional carcass layers into a single multi-sub-layer carcass layer structure. The first, second, and third sub-layers work together in one integrated layer to provide both tread and side region reinforcement, eliminating the need for separate carcass layers and their associated non-functional end portions. This merging reduces manufacturing complexity while maintaining effective reinforcement through coordinated action of the sub-layers.
Solution Approach 2:
The patent introduces a new dimensional approach by dividing the carcass layer into multiple sub-layers with different cord angle ranges within a single layer structure. Instead of using multiple complete carcass layers stacked radially, the invention creates vertical differentiation within the carcass layer itself through sub-layers having distinct cord angle characteristics, thereby achieving multi-directional reinforcement without the complexity of multiple full layers.
3Ease of manufacture
If a single carcass layer is used instead of multiple carcass layers, then manufacturing is simplified and weight is reduced, but reinforcement capability in both tread and side regions may be compromised
Solution Approach 1:
The single carcass layer is segmented into three functional sub-layers (first, second, and third sub-layers) with distinct cord angle ranges. The first and third sub-layers use smaller cord angles (15-45 degrees) to provide strong tread region reinforcement, while the second sub-layer uses larger cord angles (75-85 degrees) to provide strong side region reinforcement. This segmentation enables a single layer to perform the reinforcement functions traditionally requiring multiple layers, maintaining strength while simplifying manufacturing.
Solution Approach 2:
Each sub-layer within the single carcass layer is designed with specific cord angle characteristics optimized for particular regions. The first sub-layer targets tread region reinforcement with smaller angles, the second sub-layer targets side region reinforcement with larger angles, and the third sub-layer provides additional tread reinforcement. This local quality optimization ensures that the simplified single-layer structure maintains comprehensive reinforcement capability across different tire regions.
Data Source
AI summary
Provided is a pneumatic tire. Both terminals of a carcass layer are overlapped with each other in a tread region. The carcass layer has a triple layer structure including an inner layer positioned most inward in a tire radial direction in the tread region, an outer layer positioned most outward in the tire radial direction in the tread region, and an intermediate layer positioned between the inner layer and the outer layer in the tread region. A cord angle in the carcass layer in a tread central region with respect to a tire circumferential direction differs in at least one of the inner layer, the outer layer, and the intermediate layer from a cord angle in the carcass layer in a side region with respect to the tire circumferential direction.