Off-Road Tire Tread Design for Fuel Efficiency and Abrasion Resistance

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Solution Overview

Problem

Tires used in harsh off-road conditions face challenges in achieving both excellent off-road running performance, fuel efficiency, and abrasion resistance, as existing evaluation methods like elongation at break do not fully capture these requirements and often result in trade-offs between these factors.

Innovation Solution

A tire design featuring a tread composed of 40-80% isoprene-based rubber with specific physical properties and a tread pattern characterized by a crown and shoulder parts with a predetermined land ratio and circumferential main groove depth, optimized to balance physical properties and tread pattern characteristics for improved off-road performance, fuel efficiency, and abrasion resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the tread is designed with deep grooves and complex patterns for off-road performance, then off-road running performance is improved, but fuel efficiency deteriorates due to increased rolling resistance

Engineering Contradiction:
Improveoff-road running performanceVSAvoidfuel efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent applies parameter changes by precisely controlling the land ratio within 80-200% and groove depth within 5-20mm to optimize the balance between off-road performance and fuel efficiency. By adjusting these parameters within specific ranges, the tread pattern achieves both adequate traction for off-road conditions and sufficient contact area for fuel efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by differentiating the tread structure into crown and shoulder parts with different land ratio requirements. The shoulder parts have land ratios of 80-200% of the crown part, creating localized optimization where shoulder areas provide enhanced off-road grip while the crown maintains fuel efficiency.

Inventive Principle:
Principle #3Local quality

2Duration of action of stationary object

If the tread rubber composition is optimized for abrasion resistance with hard compounds, then abrasion resistance is improved, but off-road running performance deteriorates due to reduced flexibility and grip

Engineering Contradiction:
Improveabrasion resistanceVSAvoidoff-road running performance
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the land ratio within 80-200% and groove depth within 5-20mm to optimize the balance between off-road performance and fuel efficiency. By adjusting these parameters within specific ranges, the tread pattern achieves both adequate traction for off-road conditions and sufficient contact area for fuel efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by differentiating the tread structure into crown and shoulder parts with different land ratio requirements. The shoulder parts have land ratios of 80-200% of the crown part, creating localized optimization where shoulder areas provide enhanced off-road grip while the crown maintains fuel efficiency.

Inventive Principle:
Principle #3Local quality

3Use of energy by moving object

If the tread pattern has high land ratio for fuel efficiency, then fuel efficiency is improved, but off-road running performance deteriorates due to reduced traction in harsh conditions

Engineering Contradiction:
Improvefuel efficiencyVSAvoidoff-road running performance
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent applies parameter changes by precisely controlling the land ratio within 80-200% and groove depth within 5-20mm to optimize the balance between off-road performance and fuel efficiency. By adjusting these parameters within specific ranges, the tread pattern achieves both adequate traction for off-road conditions and sufficient contact area for fuel efficiency.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by differentiating the tread structure into crown and shoulder parts with different land ratio requirements. The shoulder parts have land ratios of 80-200% of the crown part, creating localized optimization where shoulder areas provide enhanced off-road grip while the crown maintains fuel efficiency.

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 excellent off-road running performance, maintains fuel efficiency, and enhances abrasion resistance by regulating the physical properties and tread pattern elements within specific ranges, ensuring a balanced performance across these criteria.

Implementation Method 1

when a tan δ at 30°C (tan δ 30°C) is A, A≥0.18

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentEP4008568B1tire
Publication Date: 2023.03.29 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4008568B1 patent drawingFigure 1
  • EP4008568B1 patent drawingFigure 2
  • EP4008568B1 patent drawingFigure 3

AI summary

Provided is a tire comprising a tread formed of a rubber composition comprising a rubber component comprising 40 to 80% by mass of an isoprene-based rubber, wherein the tire satisfies the following conditions (1) to (6): (1) when a tan δ at 30°C (tan δ30°C) is A, A≥0.18, (2) when a ratio (EB80°C/EB23°C) of an elongation at break at 80°C (EB80°C) to an elongation at break at 23°C (EB23°C) is B, 0.9≤B≤1.4, and (3) when an abrasion resistance index with a tire of Comparative example 1 being 100 as measured by a LAT tester is C, 110≤C≤140, (4) when a ratio (LANDSh/LANDCr) of a land ratio of the entire pair of shoulder parts (LANDSh) to a land ratio of the crown part (LANDCr) is D, 0.80≤D≤2.00, (5) when a maximum groove depth of the circumferential main groove is E (mm), 5≤E≤20, and (6) 25≤(B×C/A) × (D/E)≤200.