Circumferential Sipe Geometry for Stable Tire Wear Performance

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Solution Overview

Problem

Pneumatic tires with grooves and sipes experience rapid changes in performance as wear progresses, affecting drainage performance and tire stability.

Innovation Solution

A pneumatic tire design featuring circumferential main grooves and land portions with sipes that gradually change width from the tread surface to the sipe bottom, maintaining consistent sipe width and rigidity to ensure drainage performance while reducing abrupt changes in tire performance during wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If grooves or sipes are provided in the tread surface to improve drainage performance during wear progression, then drainage performance is improved, but the appearance of widened portions causes rapid changes in tire performance

Engineering Contradiction:
Improvedrainage performanceVSAvoidtire performance stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by designing sipes with specific width variations at different positions (first position: width decreases then increases; second position: width increases then decreases) and controlling the rate of width change in the circumferential direction. This gradual parameter change ensures drainage performance while suppressing abrupt changes in tire performance during wear progression.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements local quality by creating different sipe width change patterns at different positions along the sipe. The first position has a different width variation pattern compared to the second position, allowing each region to contribute differently to drainage performance while collectively maintaining stable tire performance characteristics.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3988335B1Pneumatic tire
Publication Date: 2024.05.29 BRIDGESTONE CORP
  • EP3988335B1 patent drawingFigure 1
  • EP3988335B1 patent drawingFigure 2
  • EP3988335B1 patent drawingFigure 3A~3B

AI summary

A pneumatic tire includes, in a land portion, at least one circumferential sipe extending in the tire circumferential direction. At a first position, from the tread surface towards the sipe bottom, the sipe width gradually decreases from the tread surface to a first changing point and then gradually increases from the first changing point to the sipe bottom. At a second position, from the tread surface towards the sipe bottom, the sipe width gradually increases from the tread surface to a second changing point and then gradually decreases from the second changing point to the sipe bottom. The sipe width at the tread surface and at the sipe bottom gradually decreases in the tire circumferential direction from the first position towards the second position, and the sipe width in a tire radial intermediate portion gradually increases in the tire circumferential direction from the first position towards the second position.