Flat Single-Wire Tire Belt Layout for Comfort and Durability
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Solution Overview
Problem
Tires with flat single-wire cords in the belt ply face challenges in balancing ride comfort and durability performance due to excessive rigidity and distortion of topping rubber, which affects steering stability and fuel efficiency.
Innovation Solution
A tire design featuring a belt layer with single-wire cords having a short diameter to long diameter ratio less than 1.00, oriented in the thickness direction, and topped with rubber of specific complex elastic modulus, ensuring reduced thickness and increased flexibility to maintain steering stability and improve fuel efficiency while enhancing ride comfort and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the thickness of topping rubber is reduced to ensure belt cord sectional area, then weight is reduced and fuel efficiency is improved, but ride comfort performance deteriorates due to excessive rigidity of the belt layer
Solution Approach 1:
The invention changes the physical parameters of the topping rubber by controlling its complex elastic modulus (E*) to be within 7-20 MPa, and by specifying the distance between single-wire cords (D) to be 0.30-1.05 mm. These parameter changes allow the topping rubber to provide sufficient flexibility for ride comfort while maintaining the reduced thickness needed for low weight and high fuel efficiency.
Solution Approach 2:
The invention uses a composite structure combining flat single-wire cords with specifically formulated topping rubber. The composite achieves optimal performance by integrating the high strength of the single-wire cords with the controlled elasticity of the topping rubber, resolving the contradiction between weight reduction and ride comfort.
2Stability of the object's composition
If the thickness of topping rubber is reduced to ensure belt cord sectional area, then steering stability is improved, but durability performance deteriorates due to increased distortion of topping rubber between cords
Solution Approach 1:
The invention controls the distance (D) between single-wire cords to be within 0.30-1.05 mm and the complex elastic modulus (E*) of topping rubber to be 7-20 MPa. These parameter changes reduce distortion of the topping rubber between cords, thereby improving durability while maintaining the thin profile needed for steering stability and fuel efficiency.
3Quantity of substance
If flat single-wire cords are used in belt ply, then topping rubber can be formed thin while maintaining cord sectional area, but the rigidity of belt layer becomes excessively large affecting ride comfort
Solution Approach 1:
The invention changes the rigidity parameter of the belt layer by controlling the complex elastic modulus (E*) of the topping rubber to be within 7-20 MPa and the distance between cords (D) to be 0.30-1.05 mm. This allows the topping rubber to be formed thin while preventing excessive rigidity, thereby maintaining both fuel efficiency and ride comfort performance.
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 achieves a balance in ride comfort, durability, and fuel efficiency by reducing the thickness of the belt layer while maintaining steering stability and improving the flexibility of the belt layer, leading to improved performance across these metrics.
Implementation Method 1
the topping rubber has a complex elastic modulus (E*) of from 7 MPa to 20 MPa, wherein the complex elastic modulus (E*) is a value measured in accordance with Japanese Industrial Standard JIS-K6394 under a condition of temperature of 70°C, initial strain of 10%, an amplitude of dynamic strain of ±1.0%, and a frequency of 10 Hz by using a dynamic viscoelasticity measurement device
Data Source
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AI summary
A belt layer 7 includes at least one belt ply 7A. The belt ply 7A has a single-wire cord 9 having a short diameter SD and a long diameter LD with a ratio SD/LD between the short diameter SD and the long diameter LD being less than 1.00, and a topping rubber 10 covering the single-wire cord 9. The single-wire cord 9 is disposed so that a direction of the short diameter SD is oriented to a thickness direction of the belt ply 7A. The topping rubber 10 has a complex elastic modulus (E∗) of from 7 MPa to 20 MPa under a condition of temperature of 70°C, initial strain of 10%, an amplitude of dynamic strain of ±1.0%, and a frequency of 10 Hz.