Pneumatic Tyre Tread Pattern with Localized Groove Widths

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Solution Overview

Problem

High-performance tires for cars and SUVs face challenges in balancing traction, braking, and noise reduction on both dry and wet surfaces, while maintaining structural integrity and resistance to aquaplaning, due to conflicting requirements of groove width and density.

Innovation Solution

A tread pattern with a reduced hollow/solid ratio, featuring transverse grooves of reduced width and adapted course, concentrated in the axially intermediate regions for optimal traction and braking, and a greater concentration of grooves for water discharge, along with a specific arrangement of circumferential grooves to enhance structural consistency and support.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If transverse grooves of important width are used, then traction ability on wet road surfaces is improved, but tyre noise increases and structural strength deteriorates

Engineering Contradiction:
Improvetraction ability on wet surfacesVSAvoidtyre noise
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies different groove widths in different regions of the tread. Transverse grooves in the central portion have a first width optimized for traction, while grooves in the shoulder portions have a second width that is different (typically narrower) to reduce noise and improve structural strength. This local differentiation allows each region to perform its specific function optimally without the negative effects of uniform wide grooves across the entire tread.

Inventive Principle:
Principle #3Local quality

2Reliability

If transverse grooves of important width are used, then water draining capability is improved, but structural strength of the tread band deteriorates

Engineering Contradiction:
Improvewater draining capabilityVSAvoidstructural strength of tread band
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent implements region-specific groove width design where the central portion (which bears more load and requires stronger structure) has narrower transverse grooves to maintain structural strength, while the shoulder portions (which require less structural support) have wider grooves to enhance water drainage. This local quality differentiation resolves the contradiction between water drainage capability and structural strength.

Inventive Principle:
Principle #3Local quality

3Reliability

If a high number of transverse grooves is used, then traction ability on wet surfaces is improved, but tyre noise increases

Engineering Contradiction:
Improvetraction ability on wet surfacesVSAvoidtyre noise
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent optimizes the number and width of transverse grooves differently in the central portion versus the shoulder portions. The central portion has a higher density of grooves with appropriate width to maximize traction on wet surfaces, while the shoulder portions have fewer or narrower grooves to minimize the continuous impact noise generated during rotation. This spatial differentiation of groove characteristics resolves the noise-traction contradiction.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2357095B9Pneumatic tyre
Publication Date: 2013.12.18 PIRELLI TYRE SPA
  • EP2357095B9 patent drawingFigure 1
  • EP2357095B9 patent drawingFigure 2
  • EP2357095B9 patent drawingFigure 2a

AI summary

A pneumatic tyre (1) for car having a tread (2) comprising a central portion (L1) disposed astride an equatorial plane (7) and two shoulder portions (8, 12). The central portion (L1) is separated from the tread shoulder portions (8, 12) by two circumferential grooves (3, 6); at least one circumferential row (9) included between a first and a second circumferential groove (3, 4) is present in the central portion (L1) . The tread (2) has a hollow/solid ratio lower than 0.28. The circumferential row (9) comprises transverse grooves (16) extending from a circumferential groove (3) to the axially adjacent one (4). Each transverse groove (16) comprises a median line having at least one first rectilinear stretch (106; 107) and one curvilinear stretch (108). The transverse grooves (16) have a smaller width than that of the circumferential grooves (3; 4).