Interlaced Shear Band Rubber for Low Rolling Resistance
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Solution Overview
Problem
Non-pneumatic tires with shear bands face challenges in reducing mass and rolling resistance while maintaining performance, particularly due to the need for materials with low energy dissipation in the shear layer.
Innovation Solution
The development of an annular shear band with an annular shear layer made from a cross-linkable rubber composition, reinforced with discrete, interlaced reinforcing elements, which reduces hysteresis and enhances fuel efficiency by optimizing the rubber composition and filler content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If materials with low energy dissipation are used in the shear layer, then rolling resistance is reduced, but the mass of material required increases due to typically lower shear modulus
Solution Approach 1:
The patent applies composite materials by combining rubber base polymers with specific filler materials (silica, carbon black) and functional additives to create a shear layer composition that achieves both low energy dissipation and adequate shear modulus. The composite formulation includes 20-60 phr of filler, with silica providing reinforcement while maintaining low hysteresis characteristics, thus resolving the contradiction between energy loss and material mass requirements.
Solution Approach 2:
The patent utilizes parameter changes by optimizing the chemical composition and physical properties of the rubber material, including molecular weight, crosslink density, and filler surface area. By adjusting these parameters within specific ranges (e.g., tan delta at 60°C between 0.08-0.18, shear modulus between 0.5-2.0 MPa), the material achieves both low energy dissipation and sufficient mechanical performance without increasing mass.
2Weight of moving object
If the shear modulus of the shear layer is increased to reduce material mass, then rolling resistance increases, but fuel efficiency decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the shear modulus within the range of 0.5-2.0 MPa and optimizing the tan delta at 60°C to be between 0.08-0.18. This balanced parameter selection ensures the shear layer has sufficient stiffness to support the tire structure while maintaining low energy dissipation, thereby preventing excessive rolling resistance and preserving fuel efficiency.
Solution Approach 2:
The patent uses composite materials with optimized filler content (20-60 phr) and specific filler types (silica with 38-42 m²/g surface area, carbon black with 25-35 m²/g surface area) to achieve the desired balance between shear modulus and energy dissipation. The composite formulation allows the shear layer to provide structural support without excessive stiffness that would increase rolling resistance.
3Strength
If filler content is increased to enhance structural integrity, then hysteresis increases, but fuel economy deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the filler content within the specific range of 20-60 phr and selecting fillers with controlled surface areas (silica: 38-42 m²/g, carbon black: 25-35 m²/g). This optimization ensures sufficient structural integrity through reinforcement while minimizing the hysteresis effect that would otherwise increase with higher filler content, thus maintaining fuel economy.
Solution Approach 2:
The patent uses a carefully balanced composite material system combining rubber base polymer with 20-60 phr of filler (including silica and carbon black) and functional additives. This composite formulation provides the necessary structural integrity and reinforcement while controlling hysteresis, resolving the contradiction between strength and energy loss.
4Loss of energy
If silica filler with high surface area is used to reduce hysteresis, then the reinforcing effect decreases, but structural integrity is compromised
Solution Approach 1:
The patent applies parameter changes by selecting silica with a specific surface area range of 38-42 m²/g, which optimizes the balance between hysteresis reduction and reinforcing effect. This controlled surface area parameter ensures the silica provides adequate reinforcement to the rubber matrix while maintaining low energy dissipation characteristics, preventing compromise of structural integrity.
Solution Approach 2:
The patent uses a composite material system that combines silica (20-40 phr with 38-42 m²/g surface area) with carbon black (10-30 phr with 25-35 m²/g surface area) and functional additives. This multi-component composite provides synergistic reinforcement while controlling hysteresis, ensuring both low energy loss and adequate structural integrity are achieved simultaneously.
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 proposed shear band design achieves improved rolling resistance and fuel economy by utilizing a rubber composition with low hysteresis and appropriate filler content, while maintaining the structural integrity and load-supporting capabilities of the tire.
Implementation Method 1
a cross-linkable rubber composition comprising, in parts by weight per 100 parts by weight of rubber (phr), between 50 phr and 100 phr of a natural rubber and between 0 phr and 50 phr of a second rubber component
Implementation Method 2
The rubber composition of the annular shear layer is based upon a cross-linkable rubber composition
Implementation Method 3
The shear layer material has a tan delta, measured at 23° C. and at 80% strain, of between 0.015 and 0.025
Data Source
AI summary
A shear band (205) that may be used e.g., in a non-pneumatic tire is provided. The shear band uses interlaced reinforcing elements (250) positioned within a shear layer of elastomeric material. A variety of configurations may be used to create the interlaced positioning of the reinforcing elements including e.g., a horizontal diamond or vertical diamond configuration. The shear layer is formed from a rubber composition having a very low hysteresis reinforced with silica and carbon black.