Pneumatic Tire Profile Element Wavy Sipe Stiffness

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Solution Overview

Problem

Pneumatic vehicle tires with wavy fine incisions in winter tires experience uneven transverse stiffness due to varying profile element widths, leading to adverse handling properties, as the number of antinodes and amplitude of sipes are not uniformly maintained across the tread, resulting in reduced rigidity and handling issues.

Innovation Solution

Designing fine incisions with the same amplitude and number of antinodes from the maximum to minimum width of the profile element, with wavelengths that decrease towards the minimum width, ensuring a consistent transverse stiffness by optimizing the interlocking effects and surface area of the sipes, and using a specific section that spans from maximum to minimum width with a defined ratio of maximum to minimum width (Bmax/Bmin = 1.1 to 7) to achieve uniform rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If fine incisions with constant wavelength and amplitude are used in both wide and narrow sections of the profile element, then the articulation effect is sufficient in wide sections, but the total surface area of fine-cut walls is reduced in narrow sections, resulting in lower stiffness

Engineering Contradiction:
Improvetransverse stiffnessVSAvoidsurface area of fine-cut walls
Core Design Contradiction:
StrengthVSArea of stationary object

Solution Approach 1:

The patent applies local quality by varying the wavelength of fine incisions according to the local width of the profile element. Narrow sections have shorter wavelengths while wide sections have longer wavelengths, optimizing the interlocking effect and surface area distribution locally to achieve uniform transverse stiffness throughout the profile element.

Inventive Principle:
Principle #3Local quality

2Shape

If the profile element has varying width along its longitudinal axis, then the lateral stiffness varies along the length, but this results in uneven transverse stiffness and adverse handling properties

Engineering Contradiction:
Improvevarying width of profile elementVSAvoiduniformity of transverse stiffness
Core Design Contradiction:
ShapeVSStability of the object's composition

Solution Approach 1:

The patent changes the wavelength parameter of the fine incisions based on the position along the profile element. By adjusting the wavelength according to the local width, the patent compensates for the varying lateral stiffness caused by the changing profile width, thereby achieving uniform transverse stiffness and improved handling properties.

Inventive Principle:
Principle #35Parameter changes

3Force

If fine incisions are arranged parallel to edges of the profile element, then the interlocking effect is optimized, but the number of antinodes varies with profile element width, reducing stiffness in narrower sections

Engineering Contradiction:
Improveinterlocking effectVSAvoidstiffness of profile element
Core Design Contradiction:
ForceVSStrength

Solution Approach 1:

The patent applies local quality by adapting the wavelength of fine incisions to the local conditions of each section. In narrow sections where the profile element width results in fewer antinodes, shorter wavelengths are used to increase the number of antinodes and enhance the interlocking effect, thereby maintaining uniform stiffness across different sections.

Inventive Principle:
Principle #3Local quality

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

This design enhances the uniformity of transverse stiffness along the profile element, improving handling properties by stiffening softer areas and reducing the impact of sipes on stiffer areas, thereby enhancing traction and wear patterns on winter surfaces.

Implementation Method 1

Another significant effect of wavy fine cuts is the interlocking effect of the opposing cut walls. The transverse forces occurring during handling deform the profile elements laterally. However, the degree of deformation of the individual profile elements depends on their differences in lateral stiffness. The interlocking cut wall surfaces allow the profile elements to brace against each other, resulting in higher transverse stiffness

Methodology Applied
Scientific EffectInterlocking effect:

Implementation Method 2

The transverse forces occurring during handling deform the profile elements laterally. However, the degree of deformation of the individual profile elements depends on their differences in lateral stiffness.

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2979903B1Pneumatic tyres for a vehicle
Publication Date: 2020.03.18 CONTINENTAL REIFEN DEUTSCHLAND GMBH
  • EP2979903B1 patent drawingFigure 1~2
  • EP2979903B1 patent drawingFigure 3~4
  • EP2979903B1 patent drawingFigure 5

AI summary

Vehicle pneumatic tire with a tread having a profile element (1), wherein at least one profile element (1) is provided with several fine cuts (2) arranged parallel to each other and spaced apart from each other, wherein this profile element (1) has a maximum width (Bmax) from which the width of the profile element decreases in the longitudinal direction of this profile element, and wherein each fine cut (2) has corresponding fine cut walls which, viewed from above the tread, have the shape of a wave with a certain amplitude (3), with a certain number of antinodes (4) and with a certain wavelength (5).To ensure uniformity of the transverse stiffness of the profile element (1), all wave-shaped fine incisions (2) in a specific section (12) of the profile element, which begins at the maximum width (Bmax) of the profile element and extends longitudinally to a minimum width (Bmin) of the profile element and ends there, have the same amplitudes (3) and the same number of antinodes (4), but wavelengths (5) of the fine incisions (2) that decrease in the direction of the minimum width (Bmin), where the minimum width (Bmin) is the narrowest width in the profile element that satisfies the condition Bmax / Bmin = 1.1 to 7, with Bmin = 5 mm to 55 mm.