Tire Tread Oblique Grooves Branch Termination

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Solution Overview

Problem

Winter tires with oblique grooves connected at branch portions compromise steering stability on dry road surfaces due to reduced rigidity near the tire equator.

Innovation Solution

Designing a tire tread with oblique grooves where branch portions terminate without connecting to other grooves, featuring a tapered land region and a spacing portion with a sipe, maintaining rigidity and enhancing on-snow performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If branch portions of oblique grooves are connected with other grooves, then on-snow performance is improved, but rigidity of land region near tire equator decreases, causing steering stability to deteriorate

Engineering Contradiction:

Improveon-snow performanceVSAvoidsteering stability on dry road surface

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The groove system is segmented into main body portions and branch portions that are disconnected. The branch portions terminate before connecting to other grooves, creating independent segments that provide snow evacuation paths without compromising the structural integrity of the land regions near the tire equator.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the tread are given different properties: the land regions near the tire equator maintain high rigidity for steering stability, while the oblique grooves with branch portions provide snow evacuation capability. The spacing portions with narrow width maintain local rigidity without preventing snow channeling function.

Inventive Principle:

Principle #3Local quality

2Productivity

If branch portions extend to cross the tire equator, then snow evacuation capability is improved, but land region rigidity decreases

Engineering Contradiction:

Improvesnow evacuation capabilityVSAvoidland region rigidity

Core Design Contradiction:

ProductivityVSStrength

Solution Approach 1:

The branch portions extend partially across the tire equator but terminate before fully connecting to the other side. This partial extension provides sufficient snow evacuation capability without the excessive action of complete connection that would compromise land region rigidity.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The connection function is extracted from the branch portions. Instead of connecting to other grooves to enhance snow evacuation, the branch portions are designed to terminate independently, extracting the snow evacuation function from the connection structure and preserving land region integrity.

Inventive Principle:

Principle #2Taking out (Extraction)

3Stability of the object's composition

If spacing portion width is reduced to maintain rigidity, then steering stability is improved, but snow clogging resistance may deteriorate

Engineering Contradiction:

Improvesteering stabilityVSAvoidsnow clogging

Core Design Contradiction:

Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The spacing portion width is optimized to a specific narrow range (0.5-1.5 times the branch portion width) that balances two competing requirements: narrow enough to maintain land region rigidity for steering stability, yet sufficient to prevent snow clogging by allowing snow to pass through without bridging.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS11155121B2Tire

Publication Date: 2021.10.26 SUMITOMO RUBBER INDUSTRIES LTD

AI summary

A tire comprises a tread portion 2. The tread portion 2 comprises a plurality of first oblique grooves 10A extending obliquely from a first tread edge Te1 positioned on one side in a tire axial direction toward a tire equator C. Each of the first oblique grooves 10A comprises a main body portion 12 extending from the first tread edge Te1 without reaching the tire equator C and a branch portion 13 branching off from the main body portion 12 and extending to cross the tire equator. The branch portion 13 terminates without being connected with other grooves than the first oblique grooves 10A.