Pneumatic Tire Groove Angles for Traction and Water Ejection

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Solution Overview

Problem

Conventional pneumatic tires do not achieve optimal traction performance, necessitating further improvements in this area.

Innovation Solution

The tire design includes a center circumferential groove with shoulder circumferential grooves, first and second lateral grooves inclined at specific angles, and shoulder lateral grooves with angles set to enhance parallel alignment, allowing efficient water ejection and improved handling stability, along with lateral sipes and raised floor faces in blocks for enhanced grip and stiffness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the inclination angle of shoulder lateral grooves is reduced to improve traction performance, then edges of grooves become more parallel to tire axial direction improving grip, but water ejection efficiency may be compromised

Engineering Contradiction:
Improvetraction performanceVSAvoidwater ejection efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The tread grooves are segmented into multiple types (center circumferential groove, shoulder circumferential grooves, first lateral grooves, second lateral grooves, and shoulder lateral grooves) with different inclination angles. This segmentation allows each groove type to perform its specific function optimally while collectively achieving both water ejection and traction goals.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the tread are assigned different groove configurations. The shoulder lateral grooves have a smaller inclination angle (θ3°) optimized for traction, while the overall groove pattern maintains water ejection pathways. This local optimization allows each region to contribute to its primary function without compromising overall performance.

Inventive Principle:
Principle #3Local quality

2Reliability

If more lateral grooves are added to shoulder side to improve water drainage, then hydroplaning resistance improves, but lug stiffness decreases reducing handling stability

Engineering Contradiction:
Improvehydroplaning resistanceVSAvoidlug stiffness
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The groove configuration is locally optimized for different tread regions. The shoulder lateral grooves are strategically positioned and angled to provide water drainage pathways while maintaining lug stiffness. The pattern ensures water ejection capability without excessive groove density that would compromise structural integrity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The groove pattern exhibits asymmetric distribution with fewer lateral grooves at the shoulder side compared to the equator side. This asymmetric design intentionally maintains higher lug stiffness at the shoulder region for handling stability while still providing adequate water drainage through the configured groove pattern.

Inventive Principle:
Principle #4Asymmetry

3Reliability

If groove depth is increased to improve water ejection capability, then hydroplaning performance improves, but manufacturing complexity and precision requirements increase

Engineering Contradiction:
Improvehydroplaning performanceVSAvoidgroove depth control
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

Rather than uniformly increasing groove depth across all regions, the design uses partial action by configuring specific groove types (shoulder lateral grooves with smaller inclination angle) to handle water ejection. This approach achieves adequate hydroplaning resistance without the excessive manufacturing precision requirements that would result from uniform deep groove formation.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP2039533B1Pneumatic tire
Publication Date: 2012.01.25 BRIDGESTONE CORP
  • EP2039533B1 patent drawingFigure 1
  • EP2039533B1 patent drawingFigure 2
  • EP2039533B1 patent drawingFigure 3

AI summary

A pneumatic tire exhibiting high traction performance. A center circumferential groove (14) is provided on the equator (CL) of the tread (12), and between shoulder circumferential grooves (18) on both sides of the center circumferential groove (14) are arranged first lateral grooves (20) formed at a smaller angle relative to the axial direction of the tire than the first lateral groove (20). One end of each first lateral groove (20) and one end of each second lateral groove (22) are made to merge at a shoulder circumferential groove (18), and shoulder lateral grooves (23) are arranged on the outer side of each shoulder circumferential groove (18). Each shoulder lateral groove (23) extends from the merging portion toward a tread end (12E) and is formed at a smaller angle relative to the axial direction of the tire than that of the first lateral groove (20). Because the angle of the shoulder lateral grooves (23) relative to the axial direction of the tire is less, traction performance of the tire increases.