Variable Width Zigzag Tire Grooves for Stone Ejection

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Solution Overview

Problem

Existing tire treads lack optimal designs for stone retention and ejection, leading to unpredictable performance in terms of noise, handling, durability, and wear resistance due to complex interactions between tread and groove characteristics.

Innovation Solution

The tire tread features a zigzag circumferential groove with varying pitch lengths and intersection angles, along with specific axial and outside angles, and the inclusion of y-shaped grooves to enhance stone ejection, characterized by a point height formula (PH=AW/(SW)×100AR×R) that balances groove width and tire dimensions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional groove designs are used, then manufacturing is simple, but stone retention and ejection performance are unpredictable

Engineering Contradiction:

Improvestone ejection performanceVSAvoidgroove geometry complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The circumferential groove is segmented into multiple sections along its length, with each section having different geometric characteristics (width, depth, orientation angles). This segmentation allows each section to perform specific functions: some sections retain stones while others eject them, creating predictable stone management behavior that traditional uniform grooves cannot achieve

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the groove are given different local geometric properties. The groove width varies from section to section, as do the inside and outside angles. This local variation in quality enables the groove to simultaneously perform stone retention in certain sections and stone ejection in others, resolving the contradiction between reliability and complexity

Inventive Principle:

Principle #3Local quality

2Reliability

If groove width is increased to improve stone ejection, then stone retention decreases, but tire structural integrity may be compromised

Engineering Contradiction:

Improvestone ejection capabilityVSAvoidtread structural integrity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The groove width is not uniformly increased throughout, but rather varies locally across different sections. This allows stone ejection to be enhanced in specific sections where wider grooves are provided, while other sections maintain narrower widths to preserve structural integrity and load-bearing capacity of the tread

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The groove system is divided into segments with different widths, allowing the tire to achieve good stone ejection performance in designated sections without compromising the overall structural strength of the tread, as other sections maintain adequate material thickness

Inventive Principle:

Principle #1Segmentation

3Object-affected harmful factors

If variable pitch lengths are used to optimize noise reduction, then handling characteristics may be affected, but groove complexity increases

Engineering Contradiction:

Improvenoise reductionVSAvoidpitch variation complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

Different pitch lengths are assigned to different sections of the groove pattern. Certain sections have pitch lengths optimized for noise reduction by disrupting sound wave patterns, while other sections maintain pitch lengths that preserve stable handling characteristics. This local differentiation allows the tire to achieve noise reduction without sacrificing handling

Inventive Principle:

Principle #3Local quality

4Reliability

If groove depth is increased to improve wear resistance, then stone retention increases, but manufacturing precision requirements increase

Engineering Contradiction:

Improvewear resistanceVSAvoidgroove depth control

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The groove system is segmented such that not all grooves have maximum depth. Instead, certain grooves are designed with optimal depths for wear resistance, while other grooves have shallower depths that are easier to manufacture with high precision. This segmentation reduces overall manufacturing precision requirements while maintaining wear resistance

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS10882361B2Tire with variable width grooves

Publication Date: 2021.01.05 BRIDGESTONE BANDAG LLC

AI summary

A tire includes a pair of sidewalls and a circumferential tread having a zigzag circumferential groove. The zigzag circumferential groove is defined by a groove bottom, a pair of groove walls, and a pair of groove edges defining an intersection between each groove wall and a top surface of the circumferential tread, wherein each of the groove edges smoothly widens and narrows along the groove. The circumferential tread has a first circumferential pitch with first and second circumferential pitch lengths. The first circumferential pitch includes a first zigzag circumferential groove segment and a second zigzag circumferential groove segment that form a first intersection angle. The second circumferential pitch includes a third zigzag circumferential groove segment and a fourth zigzag circumferential groove segment that form a second intersection angle different from the first intersection angle.