Tire Crown Reinforcement with Unequal Axial Widths
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current heavy-duty tires face challenges in maintaining endurance and wear resistance due to shear stresses and increased operating temperatures, particularly at the ends of the crown reinforcement, leading to cracking and reduced performance over long journeys at high speeds.
Innovation Solution
A tire design featuring a radial carcass reinforcement with unequal axial widths for the working crown layers, a layer of rubber mixture positioned between them, and circumferential reinforcing elements, which decouples the crown layers and distributes shear stresses, while maintaining a uniform thickness for simplified manufacturing and storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a layer of rubber mixture is positioned between the ends of working crown layers to decouple them and limit shear stresses, then endurance is improved, but the layer must exhibit very good cohesion which complicates manufacturing
Solution Approach 1:
The patent specifies precise parameter ranges for the rubber mixture layer, including thickness (1.5-3.0mm) and distance d (1.1φ-2.2φ) from the end of the narrowest working layer to the opposite working layer. These parameter controls standardize the decoupling effect while simplifying manufacturing by providing clear specification targets rather than requiring complex adaptive manufacturing processes.
Solution Approach 2:
The rubber mixture layer acts as an intermediary element between the working crown layers, providing the necessary decoupling and stress distribution. This intermediary layer with controlled thickness and material properties achieves the cohesion requirement while simplifying the overall structure compared to alternative designs that would require more complex joining mechanisms.
2Reliability
If the distance d between working layers is controlled within 1.1φ-2.2φ to optimize stress distribution, then endurance is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent defines distance d as a multiple of the cord diameter φ (1.1φ-2.2φ), creating a scalable parameter system. This approach allows manufacturing precision to be maintained across different tire sizes by using the cord diameter as a reference unit, rather than specifying absolute distances that would require different precision levels for different tire dimensions.
Solution Approach 2:
The distance control requirement is applied locally at critical positions where working layers interact with the rubber mixture layer, rather than uniformly across the entire tire structure. This localized precision requirement focuses manufacturing attention on the most critical stress distribution zones while allowing greater flexibility in other areas.
3Use of energy by moving object
If rubber mixtures with lower modulus of elasticity and loss factor are used to improve rolling resistance and fuel efficiency, then energy efficiency is improved, but the structural strength of the crown reinforcement may be compromised
Solution Approach 1:
The patent employs composite material design by combining rubber mixtures with optimized modulus and loss factor characteristics with the working crown layers and circumferential reinforcing elements. This composite structure allows the rubber layer to provide energy efficiency benefits through reduced hysteresis while the reinforcing elements maintain the necessary structural strength for heavy-duty applications.
Solution Approach 2:
The patent specifies parameter ranges for the rubber mixture properties (modulus of elasticity and loss factor) that optimize the balance between rolling resistance and structural support. By controlling these material parameters within defined ranges, the design achieves improved energy efficiency while ensuring sufficient strength through the combined action of all crown reinforcement components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design enhances endurance and wear resistance by reducing shear stresses and maintaining performance, while also improving rolling resistance and fuel efficiency through the use of specific rubber mixtures with lower modulus of elasticity and loss factor, resulting in a tire with improved durability and reduced manufacturing costs.
Implementation Method 1
a layer C of rubber mixture being positioned between at least the ends of the at least two working crown layers
Implementation Method 2
the crown reinforcement comprising at least one layer of circumferential reinforcing elements positioned radially between two working crown layers
Data Source
AI summary
A tire having a crown reinforcement formed of at least two working crown layers having unequal axial widths, a layer C of rubber mixture being positioned between at least the ends of the said at least two working crown layers, and the crown reinforcement having at least one layer of circumferential reinforcing elements positioned radially between two working crown layers. The distance d between the end of the axially narrowest working layer and the working layer separated from the axially narrowest working layer by the layer C of rubber mixture is such that 1.1ø<d<2.2ø, ø being the diameter of the reinforcing elements of the said at least one layer of circumferential reinforcing elements, and, in a meridian plane, the thickness of the layer C of rubber mixture is substantially uniform.