Tire Belt Layer Cord Density and Rubber Modulus for High-Speed Stability
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Solution Overview
Problem
Conventional pneumatic tires do not adequately address the requirements for ride comfort and steering stability during high-speed running, despite efforts to reduce rolling resistance.
Innovation Solution
A pneumatic tire design incorporating a belt layer with steel monofilament cords covered by a specific rubber composition, where the number of reinforcing cords per 5 cm, tread portion thickness, and complex elastic modulus satisfy the condition e ÷ G × E* ≥ 70, enhancing both ride comfort and steering stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If rolling resistance is reduced by optimizing rubber composition blending, then low fuel consumption performance is improved, but ride comfort and steering stability during high speed running are insufficient
Solution Approach 1:
The patent applies parameter changes by optimizing the rubber composition blending formula with specific proportions of natural rubber, styrene-butadiene rubber, and butadiene rubber, along with specific filler and additive amounts, to achieve a balance between low rolling resistance and high-speed performance. It also changes the structural parameters of the belt layer including cord arrangement, layer configuration, and thickness to simultaneously improve fuel economy and ride comfort during high-speed running
Solution Approach 2:
The patent uses composite materials by combining multiple rubber types (natural rubber, styrene-butadiene rubber, butadiene rubber) with specific fillers (carbon black, silica) and additives to create a optimized rubber composition. The belt layer itself is a composite structure combining steel cords with rubber compounds, designed to provide both low rolling resistance and excellent high-speed stability
2Use of energy by moving object
If conventional rubber composition blending is used to reduce rolling resistance, then fuel economy is improved, but steering stability during high speed running deteriorates
Solution Approach 1:
The patent changes the compositional parameters of the rubber by specifying precise proportions of different rubber types and additives, and changes the structural parameters of the belt layer including cord density, layer thickness, and arrangement pattern to maintain steering stability during high-speed operation while achieving low fuel consumption
3Ease of manufacture
If conventional belt layer design is used, then manufacturing simplicity is maintained, but ride comfort and steering stability during high speed running are insufficient
Solution Approach 1:
The patent applies local quality by creating different belt layer configurations for different regions of the tire, with specific cord arrangements and rubber compound formulations optimized for the tread area to enhance high-speed performance, while maintaining overall manufacturing feasibility through standardized construction methods
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 tire design provides improved ride comfort and steering stability during high-speed running by increasing the holding performance and reaction force of the belt layer while suppressing deformation and vibration.
Implementation Method 1
a complex elastic modulus E* (MPa) measured for the rubber composition under conditions of temperature: 70°C, initial strain: 5%, dynamic strain: ±1%, frequency: 10 Hz, and deformation mode: stretch
Data Source
AI summary
Provided is a pneumatic tire having excellent ride comfort and steering stability during high speed running. The pneumatic tire is a pneumatic tire including a tread portion and a belt layer, wherein the belt layer includes reinforcing cords made of a steel monofilament and covered with a rubber composition, and the number e of the reinforcing cords arranged (cords) per 5 cm in a tire width direction, a thickness G (mm) of the tread portion, and a complex elastic modulus E∗ (MPa) measured for the rubber composition under conditions of temperature: 70°C, initial strain: 5%, dynamic strain: ±1%, frequency: 10 Hz, and deformation mode: stretch, satisfy the following (Expression 1). e÷G×E*≥70