Pneumatic Tire Rib Sipe Configuration for Wet Grip and Rigidity

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Solution Overview

Problem

Existing pneumatic tires face challenges in improving both tire circumferential rigidity of land portions in the tread portion and wet performance simultaneously.

Innovation Solution

A pneumatic tire design featuring at least two continuous circumferential main grooves with rib-like land portions defined by these grooves, incorporating one-end-open and both-end-closed sipes that do not extend to the widthwise center line, enhancing rigidity and wet performance by optimizing sipe configurations and depths.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If grooves or sipes are added to the tread portion to improve wet performance, then water drainage capability is improved, but tire circumferential rigidity of land portions deteriorates

Engineering Contradiction:
Improvewet performanceVSAvoidtire circumferential rigidity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent divides the land portion into multiple regions by introducing sipes (one-end-open sipes and both-end-closed sipes) that segment the continuous rubber structure. This segmentation creates channels for water drainage while maintaining overall structural integrity through careful design of sipe patterns and depths, resolving the contradiction between wet performance and circumferential rigidity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different sipe configurations (one-end-open sipes with greater depth and both-end-closed sipes with lesser depth) at different locations within the land portion. This local differentiation optimizes water drainage in specific areas while preserving rigidity in other areas, addressing the contradiction between wet performance and structural strength.

Inventive Principle:
Principle #3Local quality

2Strength

If the land portion is made wider to improve circumferential rigidity, then braking and driving performance are improved, but wet performance deteriorates due to reduced water drainage capability

Engineering Contradiction:
Improvetire circumferential rigidityVSAvoidwet performance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

By segmenting the wider land portion through strategically placed sipes, the patent creates internal drainage channels that allow water to be evacuated from beneath the broader contact patch. This maintains the benefits of wider land portions for rigidity while preventing water film buildup that would compromise wet performance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The siped structure creates a porous-like configuration within the solid rubber land portion, allowing water to penetrate and drain through the sipe channels. This effective porosity enables water drainage in the wider land portion without compromising structural integrity, resolving the contradiction between rigidity and wet performance.

Inventive Principle:
Principle #31Porous materials

Data Source

PatentEP3305557B1Pneumatic tire
Publication Date: 2019.09.11 BRIDGESTONE CORP
  • EP3305557B1 patent drawingFigure 1
  • EP3305557B1 patent drawingFigure 2
  • EP3305557B1 patent drawingFigure 3

AI summary

Provided is a pneumatic tire that improves tire circumferential rigidity of a land portion in a tread portion and that also improves wet performance. The pneumatic tire includes, on a tread surface, at least two circumferential main grooves and at least one rib-like land portion defined by two of the circumferential main grooves. The rib-like land portion includes neither grooves nor sipes that extend to include a widthwise center line of the rib-like land portion. The rib-like land portion includes a one-end-open sipe and a both-end-closed sipe, the one-end-open sipe having one end open to one of the circumferential main grooves and another end closed within the rib-like land portion, and the both-end-closed sipe being arranged in the rib-like land portion. The one-end-open sipe has a widthwise sipe portion and a circumferential sipe portion, the widthwise sipe portion extending in tire width direction from one end of the one-end-open sipe and being terminated within the rib-like land portion, and the circumferential sipe portion being located closer to the widthwise center line than the both-end-closed sipe, extending in tire circumferential direction from the widthwise sipe portion, and being terminated at another end of the one-end-open sipe.