Airless Tire Spoke Rings with Variable Stiffness
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Solution Overview
Problem
Conventional airless tires with uniform spoke stiffness and diameter buckle upon contact, leading to a contact patch with straight edges, which results in increased ride harshness, noise, and soil compaction, particularly in off-highway applications.
Innovation Solution
The airless tire design incorporates spoke rings with varying diameters and stiffnesses, allowing for a curved contact patch shape by arranging central, intermediate, and outer spoke rings with distinct stiffness and diameter configurations, enhancing load distribution and reducing soil compaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If uniform stiffness spoke rings are used, then manufacturing is simplified, but ride harshness and noise increase due to straight-edged contact patches
Solution Approach 1:
The patent applies local quality by varying the stiffness of spoke rings at different radial positions. Central spoke rings have different stiffness characteristics than intermediate and outer spoke rings, creating localized structural differences that produce curved contact patch edges while maintaining overall manufacturing feasibility through modular construction
2Device complexity
If uniform diameter spoke rings are used, then structural simplicity is maintained, but soil compaction increases due to reduced contact area optimization
Solution Approach 1:
The patent implements local quality by assigning different diameters to spoke rings at different radial positions. This creates localized variations in the contact patch geometry that maximize contact area and distribute load more effectively, reducing soil compaction while maintaining a relatively simple modular structure
Solution Approach 2:
The patent applies spheroidality by creating curved contact patch edges through the varying diameter configuration of spoke rings. This curvature optimizes the contact area with the ground surface, improving load distribution and reducing soil compaction compared to straight-edged contact patches
3Shape
If variable stiffness and diameter spoke rings are used, then contact patch shape is optimized, but manufacturing complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the wheel structure into multiple discrete spoke ring segments, each with optimized stiffness and diameter characteristics. This modular approach allows for complex overall performance while maintaining relative manufacturing simplicity through standardized production of individual segments
Solution Approach 2:
The patent implements parameter changes by systematically varying the stiffness and diameter parameters of spoke rings across different radial positions. This creates the desired curved contact patch shape while managing manufacturing complexity through controlled parameter variation rather than arbitrary design changes
Data Source
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AI summary
An airless tire (200), comprising a plurality of spoke rings (210a-c), including a first spoke ring (210a) adjacent to a second spoke ring (210b). Each of the plurality of spoke rings includes an annular outer surface, an annular inner surface, and a plurality of spokes extending between the annular outer surfaces and the annular inner surfaces. The first spoke ring (210a) has a first maximum outer diameter and the second spoke ring (210b) has a second maximum outer diameter different from the first maximum outer diameter. A tread layer extends circumferentially around the annular outer surfaces of the plurality of spoke rings.