Tire Tread Zigzag Grooves Dry Stability Wet Drainage

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Solution Overview

Problem

Tires face a challenge in achieving improved steering stability on dry roads while maintaining wet performance, as reducing groove volume for increased stiffness tends to deteriorate wet performance.

Innovation Solution

A tire design featuring a tread portion with zigzag main grooves, outer and inner lateral grooves, and land portions, where the groove center line of the main grooves is positioned at the inner tread edge side of the tire equator, and outer lateral grooves terminate without communicating with the main grooves, enhancing stiffness and drainage performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If groove volume is decreased to increase the stiffness of a tread portion, then steering stability is improved, but wet performance is deteriorated

Engineering Contradiction:
Improvesteering stabilityVSAvoidwet performance
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The tread portion is segmented into multiple functional zones: a first land portion with high stiffness for steering stability, and a second land portion with drainage grooves for wet performance. This segmentation allows each zone to independently optimize its function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the tread portion are assigned different structural qualities: the first land portion has increased stiffness through specific groove positioning, while the second land portion has drainage grooves for water evacuation. This local differentiation resolves the contradiction by providing appropriate properties in appropriate locations.

Inventive Principle:
Principle #3Local quality

2Reliability

If a groove continuously extends in the tire circumferential direction, then wet drainage is improved, but steering stability is deteriorated

Engineering Contradiction:
Improvewet performanceVSAvoidsteering stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The drainage function is segmented from the steering function by placing drainage grooves only in the second land portion, while the first land portion maintains continuous circumferential structure for steering stability. This spatial segmentation allows both functions to coexist without interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The first land portion is designed with increased stiffness beforehand to prevent excessive deformation during cornering, which would otherwise compromise the effectiveness of drainage grooves in the second land portion. This preliminary structural reinforcement ensures both functions work effectively.

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP3747672B1Tire tread
Publication Date: 2023.05.24 SUMITOMO RUBBER INDUSTRIES LTD
  • EP3747672B1 patent drawingFigure 1
  • EP3747672B1 patent drawingFigure 2
  • EP3747672B1 patent drawingFigure 3

AI summary

In a tire including a tread portion having a designated mounting direction to a vehicle, steering stability on a dry road surface can be further improved while wet performance is ensured. The tire includes a tread portion 2 having a designated mounting direction to a vehicle. The tread portion 2 includes an inner tread edge Ti, an outer tread edge To, a first main groove 3 and a second main groove 4 extending in a zigzag manner, and an outer land portion 6 between the outer tread edge To and the first main groove 3. At least a part of a groove center line of the first main groove 3 is located at the inner tread edge Ti side with respect to a tire equator C. The outer land portion 6 has a plurality of outer lateral grooves 10 extending in a tire axial direction and has no groove continuously extending in a tire circumferential direction. An inner end in the tire axial direction of each outer lateral groove 10 terminates without communicating with the first main groove 3.