Run Flat Tire Sidewall Dimples for Heat Release

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Solution Overview

Problem

Existing run flat tires face issues with high weight, heat generation, and durability due to the design of their sidewalls, which affects fuel consumption and longevity in punctured states.

Innovation Solution

The tire features a design with numerous dimples on its side surfaces, where the dimples have a specific contour and arrangement to enhance heat release and reduce weight, including a land area that is less likely to wear away, combined with thermal conductivity enhancements in the sidewalls and load support layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If dimples and land are designed on sidewalls to promote heat release, then heat release performance is improved, but tire weight increases

Engineering Contradiction:
Improveheat releaseVSAvoidtire weight
Core Design Contradiction:
TemperatureVSWeight of moving object

Solution Approach 1:

The patent applies local quality by designing dimples with specific geometric parameters (area occupation ratio between 75-93%, length in circumferential direction larger than length in radial direction, depth between 0.5-4.0mm) only in the sidewall regions where heat release is most needed. This localized optimization promotes heat release through turbulent flow while minimizing the overall weight increase compared to uniform sidewall designs.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by precisely controlling the dimple geometric parameters (area occupation ratio, aspect ratio, depth, contour shape) to achieve optimal heat release performance. By adjusting these parameters within specific ranges, the patent balances heat release efficiency with weight considerations, avoiding excessive material addition while ensuring effective heat dissipation.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If land area is increased to provide structural support, then durability is improved, but heat release performance deteriorates

Engineering Contradiction:
ImprovedurabilityVSAvoidheat release
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent applies local quality by creating a differentiated sidewall structure where dimples (for heat release) and land (for structural support) coexist in specific proportions. The land areas provide necessary structural support and durability, while the dimple areas promote heat release. The area occupation ratio of dimples (75-93%) ensures sufficient land remains for structural integrity while maximizing heat release capability.

Inventive Principle:
Principle #3Local quality

3Duration of action of moving object

If run flat tire structure is implemented with load support layers, then running capability in punctured state is improved, but heat generation increases

Engineering Contradiction:
Improverunning distance in punctured stateVSAvoidheat generation
Core Design Contradiction:
Duration of action of moving objectVSTemperature

Solution Approach 1:

The patent converts the harmful heat generated by load support layers during punctured-state operation into a manageable parameter by designing dimples that promote turbulent flow and enhance heat release. The dimples transform the heat problem into a heat exchange opportunity, allowing the tire to dissipate the necessary heat and maintain running capability for extended distances in punctured conditions.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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

The tire is lightweight, efficient in heat release, and durable, allowing for extended use in punctured states with improved fuel economy and handling performance.

Implementation Method 1

In the tire, turbulent flow is generated by the dimples. The turbulent flow promotes release of heat from the tire to the atmosphere.

Methodology Applied
Scientific EffectTurbulent flow: Turbulence

Data Source

PatentEP2738020B1Pneumatic tyre
Publication Date: 2017.05.24 SUMITOMO RUBBER INDUSTRIES LTD
  • EP2738020B1 patent drawingFigure 1
  • EP2738020B1 patent drawingFigure 2
  • EP2738020B1 patent drawingFigure 3

AI summary

[Object] To provide a pneumatic tire 2 which is lightweight and is excellent in durability. [Solution] A tire 2 has a large number of dimples 62 on sidewalls 8 thereof. These dimples 62 are arranged along a circumferential direction. The contour of each dimple 62 is, for example, a rectangle. In each dimple 62, the length in a circumferential direction is larger than the length in a radial direction. The area occupation ratio of each dimple 62 is equal to or greater than 75% but equal to or less than 93%. The contour of each dimple is symmetrical about a straight line extending in the radial direction. Preferably, the depth of each dimple 62 is equal to or greater than 0.5 mm but equal to or less than 4.0 mm. The width of a land between each dimple 62 and another dimple 62 adjacent to this dimple 62 is preferably equal to or greater than 0.3 mm but equal to or less than 3.0 mm.