Pneumatic Tire Lug Groove Width Variation for Winter Traction

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Solution Overview

Problem

Conventional pneumatic tires for winter use face reduced wet braking and wear resistance performance on paved roads due to finer tread patterns and increased sipes, which compromise block rigidity, and the use of soft rubber also lowers performance on snowy roads.

Innovation Solution

A pneumatic tire design featuring lug grooves that widen from the central region to the shoulder region, with a central circumferential groove and longitudinal grooves strategically positioned to enhance block rigidity, drainage, and friction, along with sipes oriented to improve acceleration, braking, and steering stability on snowy roads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If finer tread pattern and increased number of sipes are used, then acceleration performance, braking performance, and steering stability performance on snowy roads are improved, but block rigidity drops leading to reduced wet braking performance and wear resistance performance on paved roads

Engineering Contradiction:
Improvesnowy road performanceVSAvoidblock rigidity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies local quality by differentiating groove widths in different regions: lug grooves in the shoulder region have greater width than those in the central region. This allows the shoulder region to provide enhanced snow performance through wider grooves while the central region maintains better block rigidity for wet braking performance on paved roads.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The tread pattern is segmented into distinct regions (central region and shoulder regions) with different groove configurations. The central circumferential groove and longitudinal grooves are positioned to create land portions with sipes in specific areas, allowing different parts of the tread to serve different functions - snow performance in shoulders and wet braking in the center.

Inventive Principle:
Principle #1Segmentation

2Reliability

If smaller modulus of elasticity (soft rubber) is used, then steering stability on snowy roads is improved, but block rigidity drops causing reduced wet braking performance and wear resistance performance on paved roads

Engineering Contradiction:
Improvesnowy road steering stabilityVSAvoidblock rigidity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent uses local quality by creating region-specific groove patterns that compensate for soft rubber properties. The wider lug grooves in shoulder regions enhance snow steering stability, while the overall groove configuration in land portions maintains sufficient block rigidity for wet braking performance, allowing soft rubber to be used without sacrificing paved road performance.

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

The tire achieves improved wet braking, wear resistance, acceleration, and steering stability on both snowy and paved roads by maintaining block rigidity and enhancing frictional forces through the unique groove and sipe configuration.

Implementation Method 1

enhancing frictional forces through the unique groove and sipe configuration

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2927024B1Pneumatic tire
Publication Date: 2018.04.11 BRIDGESTONE CORP
  • EP2927024B1 patent drawingFigure 1
  • EP2927024B1 patent drawingFigure 2~3
  • EP2927024B1 patent drawingFigure 4A~4C

AI summary

A pneumatic tire (10) has, in the surface of the tread (11), a central circumferential groove (12) located at the center of the contact patch width and extending circumferentially around the tire, a plurality of longitudinal grooves (13 (13a, 13b)) formed on the axially outside of the central circumferential groove (12), lug grooves (15), and blocks (16 (16a to 16c)) defined by the central circumferential groove (12), the longitudinal grooves (13), and the lug grooves (15). Each of the lug grooves (15) is formed such that its width in the shoulder region is greater than its width in the central region, and the sum of the groove area of the central circumferential groove (12) and the groove area of the longitudinal grooves (13) is smaller than the area of the lug grooves (15). As a result, the pneumatic tire (10) not only secures the wet braking performance and wear resistance performance on paved roads, but also improves the acceleration performance and braking performance and the steering stability performance on snowy roads.