Tire Sipe Design for Wet Stability and Drainage

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Solution Overview

Problem

Existing tire designs with zigzag sipes face a trade-off between draining performance and ground contact performance on wet roads, as the engagement of sipe walls can lead to reduced groove volume and compromised stability.

Innovation Solution

A tire with a sipe design featuring a first inclined portion, a second inclined portion, a bent portion, and a widened portion, where the widened portion is largest in the center and communicates with the first inclined portion, maintaining rigidity while enhancing water storage and drainage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sipe walls are designed to engage with each other to suppress block deformation, then ground contact performance is improved, but the groove volume is substantially decreased and draining performance is deteriorated

Engineering Contradiction:
Improveground contact performanceVSAvoidgroove volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The sipe structure implements local quality by creating different regions with distinct functions: the upper portion features engaged walls for rigidity and ground contact performance, while the lower portion maintains a gap to preserve groove volume for water storage. This spatial differentiation of structural properties resolves the contradiction between engagement-induced rigidity and drainage capacity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sipe is segmented into multiple functional zones: a first inclined portion with engaged walls for structural stability, and a second inclined portion with a maintained gap for water storage. This segmentation allows each zone to independently fulfill its specific function without compromising the other, thereby resolving the volume-loss problem while maintaining ground contact performance.

Inventive Principle:
Principle #1Segmentation

2Volume of stationary object

If a large gap portion is formed in the bottom part of the sipe to improve draining performance, then water storage capacity is increased, but the block is largely deformed toward the inner side and ground contact performance is deteriorated

Engineering Contradiction:
Improvewater storage capacityVSAvoidground contact performance
Core Design Contradiction:
Volume of stationary objectVSReliability

Solution Approach 1:

The gap is localized to specific regions (the second inclined portion and bottom part) rather than being uniformly distributed throughout the sipe. This localized gap placement provides water storage capacity in areas where it is most beneficial for drainage, while maintaining wall engagement in other areas to preserve block rigidity and ground contact performance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sipe structure segments the gap formation to specific zones where drainage function is prioritized, while maintaining structural integrity in zones where ground contact is critical. This selective gap placement resolves the contradiction between water storage and block deformation.

Inventive Principle:
Principle #1Segmentation

3Strength

If the sipe walls engage with each other when the block contacts the road surface, then rigidity of the block is secured, but the volume of the groove forming the sipe is substantially decreased

Engineering Contradiction:
Improverigidity of the blockVSAvoidvolume of the groove
Core Design Contradiction:
StrengthVSVolume of stationary object

Solution Approach 1:

The sipe structure exhibits dynamic behavior under load: the walls engage with each other when the block contacts the road surface to provide rigidity, while the gap portion at the bottom maintains its volume to preserve water storage capacity. This dynamic engagement mechanism allows the structure to adapt its properties based on operational conditions, resolving the contradiction between rigidity and groove volume.

Inventive Principle:
Principle #15Dynamics

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 design improves driving stability on wet roads by maintaining rigidity and enhancing draining performance through effective water storage and drainage without compromising ground contact performance.

Implementation Method 1

The engagement of the walls of the sipe described above is caused by the swelling deformation of the wall of the sipe, when the tread (block) contacts the road surface to be compressed.

Methodology Applied
Scientific EffectSwelling deformation: Elasticity

Data Source

PatentEP3640058B1tire
Publication Date: 2022.02.23 BRIDGESTONE CORP
  • EP3640058B1 patent drawingFigure 1
  • EP3640058B1 patent drawingFigure 2
  • EP3640058B1 patent drawingFigure 3A~3B

AI summary

A sipe (100) formed in a block (40) of a pneumatic tire includes a first inclined portion (110) inclined against a tire radial direction, a second inclined portion (120) formed at an outer side in the tire radial direction with respect to the first inclined portion (110) and inclined in a direction opposite to the first inclined portion (110) with respect to the tire radial direction, a bent portion (130) communicated with the first inclined portion (110) and the second inclined portion (120) and bent to be protruded toward a direction in which a gap between the first inclined portion (110) and the second inclined portion (120) becomes narrow, and a widened portion (160) formed at an inner side in the tire radial direction with respect to the first inclined portion (110) and widened in a groove width more than the first inclined portion (110). The widened portion (160) is communicated with the first inclined portion (110) and formed at a side of the bent portion (130) with respect to an extension line of the first inclined portion (110).