Narrow-Width Radial Tire Geometry and Rubber Modulus
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Solution Overview
Problem
Narrow-width, large-diameter radial tires face challenges in improving both wet performance and rolling resistance, with existing solutions not adequately addressing the need for enhanced braking performance on wet roads and reduced rolling resistance.
Innovation Solution
A pneumatic radial tire design with specific dynamic storage modulus and loss tangent values for tread and buttress rubber, combined with a narrow-width, large-diameter configuration, and a unique tread pattern to optimize wet performance and rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the tire section width is increased to improve load capacity and ride comfort, then the vehicle space is compressed and air resistance increases, but fuel efficiency deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the tire's geometric parameters (section width SW and outer diameter OD) to satisfy a specific relationship SW/OD ≤ 0.26. This parameter optimization allows the tire to achieve adequate load capacity while minimizing air resistance and improving fuel efficiency, directly resolving the contradiction between load capacity and fuel efficiency.
2Loss of energy
If the tire diameter and width are increased to reduce rolling resistance coefficient, then fuel efficiency improves, but tire weight increases and air resistance increases, resulting in increased vehicle resistance
Solution Approach 1:
The patent optimizes the geometric parameters by maintaining SW/OD ≤ 0.26, which allows achieving low rolling resistance coefficient without excessive tire weight increase. This parameter optimization resolves the contradiction between reducing rolling resistance and controlling tire weight.
Solution Approach 2:
The patent applies local quality by using different rubber compositions with specific dynamic storage modulus ranges for different tire portions (tread rubber: 6.0-12.0 MPa, buttress rubber: 1.5-3.5 MPa). This localized material property differentiation optimizes the balance between wet performance, rolling resistance, and overall tire performance.
3Reliability
If the dynamic storage modulus E' of tread rubber is increased to improve wet performance, then braking performance on wet road surface improves, but rolling resistance may increase
Solution Approach 1:
The patent applies local quality by specifying different dynamic storage modulus ranges for different rubber portions: tread rubber (6.0-12.0 MPa) for wet performance and buttress rubber (1.5-3.5 MPa) for rolling resistance control. This localized property differentiation resolves the contradiction between wet performance and rolling resistance.
Solution Approach 2:
The patent optimizes the dynamic storage modulus parameter E' within specific ranges for different rubber compositions and temperatures (30°C and 60°C measurements). This parameter optimization allows achieving good wet performance while controlling rolling resistance through precise material property control.
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 achieves improved wet performance and reduced rolling resistance through the specified rubber properties and tire geometry, enhancing braking and fuel efficiency.
Implementation Method 1
the dynamic storage modulus E' and loss tangent tanδ are related to vulcanized rubber, and are values obtained by applying an initial load of 160 g on a test piece
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
Provided is a narrow-width, large-diameter radial tire which is a passenger-vehicle pneumatic radial tire with improved wet performance and rolling resistance performance. When the passenger-vehicle pneumatic radial tire of the disclosure is assembled to a rim and filled with an internal pressure of 250kPa or more, an SW/OD ratio of a sectional width SW to an outer diameter OD(mm) of the tire is 0.26 or less if the tire has a sectional width SW of less than 165(mm), whereas a sectional width SW and an outer diameter OD(mm) of the tire satisfy a relation of 2.135 ×SW+282.3≤OD if the tire has a sectional width SW of 165(mm) or more, a dynamic storage modulus E' at 30°C of the tread rubber is 6.0MPa to 12.0MPa and a loss tangent tanδ at 60°C of the tread rubber is 0.05 to 0.15, and a dynamic storage modulus E' at 30 °C of the buttress rubber is 1/2 or less, and a loss tangent tanδ at 60°C of the buttress rubber is 0.1 or less.