Tread Base Rubber Composition for Rolling Resistance and Noise
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Solution Overview
Problem
Current tire technologies face a trade-off between achieving low rolling resistance for improved fuel efficiency and reducing pass-by noise, with existing rubber compositions either worsening noise levels when reducing rolling resistance or increasing noise when reducing rolling resistance.
Innovation Solution
A tire design with a base rubber composition optimized by adjusting the tanδ ratio (0 °C to 30 °C) and thickness distribution, incorporating specific rubber components and fillers, such as styrene butadiene rubber and silica, to enhance both rolling resistance and pass-by noise performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the tanδ of the rubber composition is reduced to improve rolling resistance, then fuel efficiency is improved, but pass-by noise performance worsens
Solution Approach 1:
The patent applies local quality by differentiating the tanδ requirements for different tread regions. The center portion of the tread (base rubber) uses a rubber composition with tanδ of 0.080 or less at 30°C to minimize rolling resistance and improve fuel efficiency. The outer side portions (cap rubber) use a different composition with tanδ of 0.120 or less but with specific attention to noise reduction. This regional differentiation allows each area to optimize for its primary function while maintaining overall performance balance.
Solution Approach 2:
The patent employs composite materials by combining multiple rubber compositions with different tanδ characteristics into a single tread structure. The base rubber and cap rubber use different rubber formulations - the base rubber may use natural rubber or SBR with specific filler combinations for low rolling resistance, while the cap rubber uses compositions optimized for noise reduction. This composite approach allows simultaneous optimization of both rolling resistance and pass-by noise performance through material diversity.
2Object-generated harmful factors
If the thickness of the base rubber is increased to improve pass-by noise performance, then noise is reduced, but rolling resistance may worsen
Solution Approach 1:
The patent applies local quality by specifying that the base rubber thickness in the center portion of the tread should be greater than in the outer side portions. This thickness differentiation allows the center portion to provide noise reduction benefits through increased material damping, while the thinner outer portions maintain flexibility and reduce overall rolling resistance. The specific configuration ensures that noise reduction is achieved where most needed without excessive penalty to fuel efficiency.
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 optimized tire composition achieves a balance between reduced rolling resistance and improved pass-by noise performance, maintaining wear resistance while ensuring both factors are improved at higher levels.
Implementation Method 1
30 °C tanδ of the base rubber is 0.20 or less, and a ratio (0 °C tanδ/30 °C tanδ) of 0 °C tanδ to 30 °C tanδ of the base rubber is 2.90 or more, where 30 °C tanδ is tanδ at 10 Hz and 30 °C, and 0 °C tanδ is tanδ at 10 Hz and 0 °C
Data Source
Figure 1
AI summary
Provided is a tire having excellent rolling resistance and improved pass-by noise performance. A tire comprises a tread portion that includes a base rubber and a cap rubber located on an outer side of the base rubber in a tire radial direction, wherein a thickness of the base rubber in the tire radial direction is 1 mm or more, 30 °C tanδ of the base rubber is 0.20 or less, and a ratio 0 °C tanδ/30 °C tanδ of 0 °C tanδ to 30 °C tanδ of the base rubber is 2.90 or more, where the 30 °C tanδ is tanδ at 10 Hz and 30 °C, and the 0 °C tanδ is tanδ at 10 Hz and 0 °C.