Tire Tread Hexagonal Block Chamfering Stone Ejection

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Solution Overview

Problem

Heavy duty tires with hexagonal blocks in the tread portion face issues with stone entrapment in lateral grooves, which can be reduced but at the cost of compromising wet performance due to the measures taken to prevent it.

Innovation Solution

The tire design features zigzag circumferential grooves and lateral grooves that form hexagonal blocks, with chamfered corners in the hexagonal blocks to create an asymmetric structure that self-ejects foreign objects and maintains groove volume, enhancing both stone entrapment resistance and wet performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a raised part is provided in the groove bottom to suppress stone entrapment, then stone entrapment resistance is improved, but groove volume is reduced which worsens wet performance

Engineering Contradiction:

Improvestone entrapment resistanceVSAvoidgroove volume

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent applies asymmetry by providing chamfered parts at corners of hexagonal blocks adjacent to lateral grooves, where the chamfered parts are positioned at different locations on opposite sides of each groove. This asymmetric configuration creates a self-ejection mechanism for stones while preserving the full groove volume, thereby improving stone entrapment resistance without compromising wet performance.

Inventive Principle:

Principle #4Asymmetry

2Strength

If hexagonal blocks are used with high rigidity to suppress movement and deformation, then wear resistance is improved, but stone entrapment tendency increases in lateral grooves

Engineering Contradiction:

Improvewear resistanceVSAvoidstone entrapment tendency

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent introduces asymmetry through chamfered parts at the corners of rigid hexagonal blocks. These chamfered parts are strategically positioned at different locations on opposite sides of lateral grooves, creating an asymmetric structure that generates self-ejection force against stones. This allows the maintenance of high block rigidity for wear resistance while eliminating the stone entrapment issue through the asymmetric corner design.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent converts the potential harm of stone entrapment into a benefit by designing chamfered corners that actively eject stones. The rigid hexagonal blocks, which initially cause stone entrapment due to their stability, are modified with asymmetric chamfered parts that utilize the same rigidity to create a self-cleaning effect, turning the stationary nature of the blocks into a mechanism for stone ejection.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS11505007B2Tire

Publication Date: 2022.11.22 SUMITOMO RUBBER INDUSTRIES LTD

AI summary

A tire comprises a tread portion provided with zigzag circumferential grooves and lateral grooves so that hexagonal blocks are formed between the zigzag circumferential grooves. Corners of the hexagonal blocks adjacent to each other through the lateral grooves are partially chamfered to have chamfered parts, with respect to each of the lateral grooves, the chamfered part of the corner of the hexagonal block abutting on the lateral groove on one side in the tire circumferential direction is located in a different position in the longitudinal direction of the lateral groove than the chamfered part of the corner of the hexagonal block abutting on the lateral groove on the other side in the tire circumferential direction.