Airless Tire Shear Layer Design for Rolling Resistance Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Airless tires exhibit high rolling resistance, leading to energy loss, heat generation, and reduced durability, which in turn increases fuel consumption and affects vehicle performance.
Innovation Solution
The airless tire design incorporates a shear layer with a first portion of elastomer having a specific loss tangent and shear modulus, and a second portion of a different material, arranged within the tread ring to reduce rolling resistance and enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shear layer made of elastomer is arranged in the tread ring of an airless tire, then the tire can support loads without high-pressure air, but the shear layer generates heat due to energy loss, reducing durability
Solution Approach 1:
The shear layer is divided into two portions with different materials: a first portion with low loss tangent (≤0.10) for heat reduction and a second portion for structural support. This local differentiation allows each region to perform its specific function optimally, reducing overall heat generation while maintaining durability
Solution Approach 2:
The shear layer uses a composite structure combining two different elastomer materials. The first portion uses elastomer with specific low-loss properties (tanδ≤0.10, Ee≥1.0 MPa) to minimize heat generation, while the second portion uses different elastomer material to provide necessary mechanical strength and structural integrity
2Strength
If the shear layer is made of conventional elastomer material, then the tread ring maintains structural integrity, but rolling resistance increases by about 2.5 times compared to pneumatic tires
Solution Approach 1:
Different portions of the shear layer are assigned different material properties: the first portion optimized for low energy loss (tanδ≤0.10) to reduce rolling resistance, while the second portion provides structural integrity. This localized functional differentiation resolves the contradiction between strength and energy efficiency
Solution Approach 2:
The invention changes the material parameters of the shear layer by selecting elastomer with specific loss tangent (≤0.10) and shear modulus (≥1.0 MPa) values. This parameter optimization reduces energy loss and rolling resistance while maintaining necessary structural properties
3Loss of energy
If the first portion of the shear layer has a width of 10%-70% of the maximum width, then rolling resistance is reduced while maintaining adequate structural support
Solution Approach 1:
The first portion is designed with width 10%-70% of the maximum shear layer width, creating an optimized balance where the low-loss material reduces rolling resistance in the critical contact region, while the second portion provides sufficient structural support. This proportional design resolves the trade-off between energy efficiency and structural strength
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 design effectively reduces rolling resistance, prevents heat-related durability issues, and improves fuel efficiency while maintaining steering stability.
Implementation Method 1
a loss tangent (tanδ) and a shear modulus (Ee) (unit: MPa) of the first portion at a temperature of 30 °C satisfying the following Equations (1) and (2)
Data Source
Figure 1
Figure 2
Figure 3
AI summary
[Problem to be solved] To provide an airless tire that has a small rolling resistance. [Solution] An airless tire 1 is provided that includes a cylindrical tread ring 2 that has a ground contact surface (2a). The tread ring 2 has therein a reinforcing body 6. The reinforcing body 6 includes an annular first reinforcing cord layer 7 that extends in a tire circumferential direction, an annular second reinforcing cord layer 8 that is arranged on a tire radial direction inner side of the first reinforcing cord layer 7 and extends in the tire circumferential direction, and a shear layer 9 that is formed of an elastomer and is arranged between the first reinforcing cord layer 7 and the second reinforcing cord layer 8. The shear layer 9 includes a first portion 10 and a second portion 11, a loss tangent (tanδ) and a shear modulus (Ee) (unit: MPa) of the first portion 10 at a temperature of 30 °C satisfying the following Equations (1) and (2), and the second portion 11 being formed of a material different from the first portion 10. tanδ≦0.06 Ee/tanδ≧1500