Airless Tire Spoke Geometry for Roughness Absorption
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Solution Overview
Problem
Airless tires lack the ability to effectively absorb road roughness and maintain riding comfort due to insufficient deformation of spoke pieces, leading to increased vertical motion and reduced durability.
Innovation Solution
The airless tire features spoke pieces made of polymer material with specific geometric configurations, including a straight radial length at least 1.05 times the no-load length and a curved radial length at least 1.03 times the straight length under base-load conditions, allowing for enhanced deformation and impact absorption, while maintaining steering stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If spoke pieces are made rigid to maintain tire structure, then tire rigidity is improved, but ability to absorb road roughness deteriorates
Solution Approach 1:
The spoke piece includes a curved portion that allows elastic deformation when the tire encounters road roughness. The curved geometry enables the spoke to flex and absorb impacts while maintaining overall structural integrity, resolving the contradiction between rigidity and roughness absorption capability.
Solution Approach 2:
The patent specifies precise dimensional parameters for the spoke piece including straight radial length Ls, curved radial length Lc, and various angle parameters (α, β, γ). By optimizing these geometric parameters, the spoke achieves both sufficient rigidity for structural support and adequate flexibility to deform elastically under load, simultaneously satisfying both requirements.
2Reliability
If spoke pieces are designed with larger deformation capacity, then riding comfort is improved, but steering stability deteriorates
Solution Approach 1:
The curved portion is strategically positioned and dimensioned to allow localized deformation at specific points in the spoke structure, while the overall spoke geometry and connection points maintain sufficient stiffness. This localized flexibility provides roughness absorption for comfort without compromising the global structural stability needed for steering control.
Solution Approach 2:
The patent defines specific parameter ranges including the ratio of curved radial length to straight radial length (Lc/Ls), and angle parameters that control the curvature geometry. These parameter optimizations ensure the spoke deforms sufficiently to improve comfort while maintaining adequate steering stability through proper geometric configuration.
3Reliability
If spoke pieces are made longer to increase deformation range, then impact absorption is improved, but tire structural integrity deteriorates
Solution Approach 1:
The curved portion provides an efficient geometric configuration that maximizes deformation capability within a compact length. The curvature allows the spoke to achieve greater effective deformation range without proportionally increasing the straight radial length, thereby maintaining structural integrity while improving impact absorption through elastic deformation of the curved section.
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 significantly reduces vertical motion and enhances riding comfort by absorbing road roughness and maintaining tire rigidity, with improved durability and reduced impact from bumps.
Implementation Method 1
the spoke structure including a polymer material and connecting the tread ring and the hub... each of the spoke pieces has a straight radial length LSb of at least 1.05 times a straight radial length LSa... when positioned at 0° on a coordinate around the tire axis
Data Source
AI summary
An airless tire includes a tread ring, a hub positioned on radially inner side of the ring, and a spoke structure including polymer material and connecting the ring and hub, the structure including spoke pieces arrayed in circumferential direction. Each spoke piece has a tread connecting portion, a hub connecting portion, and a spoke curved portion between the tread and hub connecting portions, each spoke piece has straight radial length LSb of at least 1.05 times straight radial length LSa and curved radial length LLb of at least 1.03 times LSb when positioned at 0° on coordinate around the tire axis where a perpendicular line extending vertically upward from the tire axis is set 0°, LSb is measured along the base line under base-load condition, LSa is measured along the base line under no-load condition, and LLb is measured along a curve of each spoke piece under the base-load condition.