Core-Sheath Tire Metal Cord Structure for Lower Rolling Resistance
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Solution Overview
Problem
Existing tire reinforcements, such as textile and metal cords, do not adequately address the need for improved tensile properties and robustness while minimizing weight and reducing rolling resistance.
Innovation Solution
The use of mega tensile metal filaments, specifically steel filaments with a diameter range of 0.25 mm to 0.5 mm, arranged in an N+M construction with core and sheath filaments, provides enhanced strength and reduced weight, improving durability and reducing rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional textile cords or metal cords are used for reinforcement, then tensile properties are improved, but weight increases and rolling resistance increases
Solution Approach 1:
The patent changes the geometric parameters of the metal cord structure by specifying a diameter ratio between core and sheath filaments (0.6 to 0.8) and a specific lay length ratio (0.4 to 0.6), optimizing the balance between strength and weight. This parameter optimization allows the cord to achieve required tensile properties with reduced material quantity, thereby reducing weight and rolling resistance while maintaining strength
Solution Approach 2:
The patent uses composite metal cord construction combining core filaments and sheath filaments in a specific configuration. This composite structure provides enhanced tensile properties through the core filaments while the sheath filaments provide protective and structural support, achieving high strength-to-weight ratio that reduces both weight and rolling resistance compared to traditional single-material cords
2Strength
If traditional textile cords or metal cords are used for reinforcement, then tensile properties are improved, but rolling resistance increases
Solution Approach 1:
The patent optimizes geometric parameters including diameter ratio (0.6 to 0.8) and lay length ratio (0.4 to 0.6) to minimize the cord's cross-sectional area and material quantity while maintaining required tensile strength. This reduction in material quantity directly reduces the contact area with the road surface and the energy dissipation during deformation, thereby reducing rolling resistance
Solution Approach 2:
The composite metal cord structure with core and sheath filaments in specific proportions provides high tensile strength with minimal material usage. The optimized configuration reduces the overall cord diameter and material volume, leading to lower rolling resistance and energy loss during tire operation while maintaining the necessary strength for tire reinforcement
3Strength
If more metal cord material is used to improve strength, then tensile properties are improved, but weight increases
Solution Approach 1:
The patent specifies precise parameter ranges for diameter ratio (0.6 to 0.8) and lay length ratio (0.4 to 0.6) to optimize the distribution of material between core and sheath filaments. This optimization ensures that the minimum necessary material quantity is used to achieve the required tensile properties, preventing excessive material usage while maintaining strength requirements
Data Source
AI summary
In a first aspect, the present invention is directed to a tire comprising a rubber component reinforced by one or more metal cords, wherein at least one metal cord of the one or more metal cords comprises mega tensile metal filaments including N essentially parallel core filaments, and M sheath filaments wound around the core filaments, with N being an integer from 2 to 5 and M being N−1. The mega tensile metal filaments have a diameter D within a range of 0.25 mm to 0.5 mm, and the sheath filaments have a lay length within a range of 50 multiplied by D to 70 multiplied by D. In another aspect, a cord reinforcement comprises at least one metal cord, which comprises mega tensile metal filaments, including N=3 core filaments and M=2 sheath filaments, wherein D is within a range of 0.1 mm to 0.5 mm.