Airless Tire Tread Ring Reducing Rolling Resistance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Airless tires experience higher rolling resistance compared to pneumatic tires due to the use of conventional tread rubber materials, which result in increased hysteresis losses, leading to deteriorated performance.
Innovation Solution
The implementation of a sandwich structure for the tread ring with a shear rubber layer sandwiched by reinforcing cord layers, utilizing a rubber composition containing butadiene rubber, α, β-unsaturated carboxylic acid metal salt, and peroxide in the topping rubber portions, which co-cross-link to enhance elasticity and reduce rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional tread rubber material is used for the tread ring in an airless tire, then grip performance and wear resistance are improved, but rolling resistance increases to about 2.5 times that of a pneumatic tire
Solution Approach 1:
The patent changes the physical and chemical parameters of the rubber material by introducing a dual-vulcanization system with both sulfur and peroxide crosslinking agents. This creates a hybrid crosslinked network that modifies the rubber's viscoelastic properties, specifically reducing hysteresis loss while maintaining grip and wear resistance. The parameter change in crosslinking chemistry directly addresses the rolling resistance issue without sacrificing reliability.
Solution Approach 2:
The patent creates a composite rubber composition that combines butadiene rubber with specific additives including sulfur, peroxide, and various functional agents. This composite material integrates multiple crosslinking mechanisms (sulfur vulcanization and peroxide crosslinking) to achieve a balance between grip performance, wear resistance, and reduced rolling resistance. The composite nature allows simultaneous optimization of conflicting properties.
2Loss of energy
If a tread structure different from pneumatic tires is used to reduce rolling resistance, then rolling resistance decreases to pneumatic tire levels, but steering stability may be compromised
Solution Approach 1:
The patent modifies the rubber's viscoelastic parameters through dual crosslinking, achieving a specific balance of stiffness and damping characteristics. The peroxide crosslinking increases elastic recovery and reduces permanent deformation, while sulfur vulcanization maintains flexibility and grip. This parameter optimization ensures the tread ring maintains steering stability while operating at pneumatic-tire-level rolling resistance.
Solution Approach 2:
The patent applies different rubber compositions to different regions of the tread ring. The top surface rubber contains the dual-vulcanization system optimized for low rolling resistance, while the inner rubber layer has a different composition optimized for structural integrity and steering response. This local differentiation allows simultaneous optimization of rolling resistance and steering stability in different functional zones.
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
This configuration reduces rolling resistance while maintaining excellent steering stability and durability by distributing load through tensile elastic forces and minimizing rubber deformation, outperforming conventional sulfur-vulcanized rubber materials.
Implementation Method 1
utilizing a rubber composition containing butadiene rubber, α, β-unsaturated carboxylic acid metal salt, and peroxide in the topping rubber portions, which co-cross-link to enhance elasticity
Implementation Method 2
co-cross-link to enhance elasticity and reduce rolling resistance
Implementation Method 3
distributing load through tensile elastic forces
Implementation Method 4
solid parts, specifically, the tread ring and the spoke plates, that have large hysteresis losses as compared to the air
Data Source
Figure 1
Figure 2
Figure 3
AI summary
[Problem to be solved] To reduce rolling resistance in an airless tire. [Solution] A tread ring 2 of an airless tire 1 includes a shear rubber layer 7 that is provided between first and second reinforcing cord layers 5, 6 that are respectively arranged on radial direction inner and outer sides. At least one of an inner topping rubber portion (9i) of the first reinforcing cord layer 5 and an inner topping rubber portion (11i) of the second reinforcing cord layer 6 is formed of a rubber composition (G) that contains 10 - 80 parts by weight of an α, β-unsaturated carboxylic acid metal salt with respect to 100 parts by mass of a rubber component, in which a content rate of a butadiene rubber is 10 - 100% by mass, and contains a peroxide.