Tyre tread sipe undercut profile for wear and traction

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Solution Overview

Problem

Heavy load vehicle tires face a trade-off between optimal traction, acceleration, and lateral stability on snowy or wet surfaces, which contrasts with kilometric yield and reduced noise/vibrations, due to excessive wear and friction from transversal sipes in the tread design.

Innovation Solution

A tread design featuring transversal sipes with an undercut profile that allows controlled opening and closing, reducing friction between adjacent blocks and wear, while maintaining traction and stability through adequate embedding and snow trapping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If transversal sipes are provided in the tread design to improve traction and lateral stability, then traction capability and lateral stability are improved, but excessive wear and friction occur leading to reduced kilometric yield and increased noise/vibrations

Engineering Contradiction:
Improvetraction capabilityVSAvoidkilometric yield
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The sipe profile is designed with different characteristics at different locations: the undercut portion provides strong embedding for traction, while the tapered portion allows controlled opening and closing to reduce wear. This local differentiation of the sipe structure enables simultaneous optimization of traction capability and durability.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sipe structure is designed to dynamically open and close during tyre operation. The tapered profile allows the sipe to open when needed for traction and snow trapping, then close to reduce friction and wear during rolling. This dynamic behavior optimizes both performance and longevity.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If transversal sipes with embedding portions are used to enhance lateral stability through mutual constraint of blocks, then lateral stability is improved, but friction and wear between adjacent blocks increase leading to noise and vibrations

Engineering Contradiction:
Improvelateral stabilityVSAvoidnoise and vibrations
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The sipe profile concentrates the embedding function in the undercut portion while the tapered portion provides a smooth transition that minimizes friction. This local specialization allows strong lateral constraint without excessive friction-induced noise and vibrations.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The design converts the potentially harmful friction between blocks into a beneficial controlled opening/closing mechanism. The tapered profile allows the blocks to move relative to each other in a controlled manner, reducing friction and wear while maintaining the stabilizing embedding effect.

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

3Reliability

If deep transversal sipes are provided to improve snow trapping and traction on snowy surfaces, then traction on snow is improved, but wear and friction increase reducing tyre lifespan

Engineering Contradiction:
Improvetraction on snowVSAvoidtyre lifespan
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The sipe is designed to dynamically adjust its opening state based on operating conditions. The tapered profile enables deep sipes to open fully for snow trapping and traction, then close during rolling to minimize wear, thus extending tyre lifespan while maintaining snow traction capability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The sipe profile parameters are optimized to provide sufficient depth for snow trapping while using the tapered geometry to control the opening and closing behavior. This parameter optimization ensures deep sipes provide traction without excessive wear.

Inventive Principle:
Principle #35Parameter changes

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 solution enhances traction, acceleration, and lateral stability on snowy and wet surfaces while increasing kilometric yield and reducing noise and vibrations by controlling sipe opening and wear through the undercut profile.

Implementation Method 1

The tread design features transversal sipes with an undercut profile that allows controlled opening and closing, reducing friction between adjacent blocks

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2234823B1Tyre for vehicle wheels
Publication Date: 2012.12.05 PIRELLI TYRE SPA
  • EP2234823B1 patent drawingFigure 1
  • EP2234823B1 patent drawingFigure 2
  • EP2234823B1 patent drawingFigure 3

AI summary

A tyre (1) for vehicle wheel, in particular for heavy load vehicle wheels, has a tread band (10) comprising an annular central portion (10i) astride an equatorial plane (Y-Y) and two annular shoulder portions (10ii) arranged on axially opposite sides with respect to the annular central portion (10i). The annular central portion (10i) is separated from each annular shoulder portion (10ii) by a respective circumferential groove (16). The annular central portion (10i) comprises a plurality of blocks (20) arranged along at least one circumferential row (21) comprised between two circumferential grooves (16), and at least one transversal sipe arranged between two circumf erentially consecutive blocks (20). The transversal sipe has a main surface orientated in a substantially radial direction and provided with at least one deformation defining in the adjacent blocks respective portions of mutual constraint. The deformation comprises at least one undercut portion in a circumferential direction.