Airless Tire Segmented Spoke Design for Uniformity

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Solution Overview

Problem

The existing airless tire designs face limitations in design flexibility and uniformity performance due to the complexity of mold structures required to prevent undercut in spoke molding, which restricts the ability to improve both uniformity and design performance.

Innovation Solution

The airless tire is divided into two separate tire pieces that are integrated along the tire axial direction, allowing for independent molding and arrangement of spokes, which enhances design flexibility and prevents contact between spokes, thereby improving uniformity and design performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If spokes are molded using conventional injection molding to prevent undercut, then manufacturing reliability is improved, but design flexibility deteriorates

Engineering Contradiction:
Improvemanufacturing reliabilityVSAvoiddesign flexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The airless tire is divided into multiple tire pieces (first tire piece and second tire piece), each containing a subset of spokes. This segmentation allows each piece to be molded separately using simple mold structures without undercut issues, while the overall tire achieves complex spoke designs through assembly of multiple pieces.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If spokes are designed with complex shapes to improve design performance, then design flexibility is improved, but mold structure complexity increases

Engineering Contradiction:
Improvedesign flexibilityVSAvoidmold structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Complex spoke designs are achieved by dividing the tire into multiple pieces, each with simpler spoke configurations that can be molded with straightforward mold structures. The first tire piece contains first spokes and the second tire piece contains second spokes, allowing complex overall design without complex individual molds.

Inventive Principle:
Principle #1Segmentation

3Strength

If tire is manufactured as a single piece to improve structural integrity, then strength is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvestructural integrityVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The tire is segmented into multiple pieces that are subsequently assembled together. The first tire piece and second tire piece are joined through their inner periphery parts, creating a multi-piece structure that maintains structural integrity while simplifying individual manufacturing processes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple separately molded tire pieces are combined through assembly of their inner periphery parts. The first inner periphery part and second inner periphery part are fixed together to form the complete tire structure, merging simpler components into a functional whole.

Inventive Principle:
Principle #5Merging (Combining)

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 approach allows for improved design flexibility and enhanced uniformity and design performance by enabling separate manufacturing and integration of tire pieces, reducing the complexity of mold structures and preventing spoke contact, thus improving riding comfort and drainage performance.

Implementation Method 1

molded by injecting an elastic material such as elastomer into cavities of a mold and curing the elastic material by a chemical change or a temperature change

Methodology Applied
Scientific EffectChemical change: Chemical Bonding

Implementation Method 2

molded by injecting an elastic material such as elastomer into cavities of a mold and curing the elastic material by a chemical change or a temperature change

Methodology Applied
Scientific EffectTemperature change: Thermal Expansion

Data Source

PatentEP3162592B1Airless tire
Publication Date: 2019.04.24 SUMITOMO RUBBER INDUSTRIES LTD
  • EP3162592B1 patent drawingFigure 1
  • EP3162592B1 patent drawingFigure 2
  • EP3162592B1 patent drawingFigure 3

AI summary

An airless tire (1) includes a first tire piece (10) and a second tire piece (20). The first tire piece (10) includes a first tread ring (11) that has a ground contact surface (11a), a first inner periphery part (12) that is arranged on a radial direction inner side of the first tread ring (11), and multiple first spokes (13) for connecting the first tread ring (11) to the first inner periphery part (12). The second tire piece (20) includes a second tread ring (21) that has a ground contact surface (21a), a second inner periphery part (22) that is arranged on a radial direction inner side of the second tread ring (21), and multiple second spokes (23) for connecting the second tread ring (21) to the second inner periphery part (22). The first tire piece (10) and the second tire piece (20) are integrated in a state of being aligned in a tire axial direction.