Tire Crown Tie Bars for Wet Grip and Noise Balance

Solution Overview

Problem

Tires with large lateral grooves for improved wet performance often compromise noise performance due to decreased pattern rigidity, leading to increased deformation and pumping sound.

Innovation Solution

A tire design featuring a crown longitudinal groove with misaligned first and second crown lateral grooves and crown tie bars, along with middle and shoulder tie bars, to enhance rigidity and drainage while minimizing noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the volume of lateral groove is increased to improve wet performance, then water drainage capability is improved, but pattern rigidity of tread portion is decreased

Engineering Contradiction:

Improvewet performanceVSAvoidpattern rigidity

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The lateral groove is divided into multiple segments by crown tie bars that protrude from the groove bottom. This segmentation maintains the overall groove volume for water drainage while creating rigid segments that resist deformation, thereby resolving the contradiction between wet performance and pattern rigidity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The crown tie bars are strategically positioned at specific locations within the lateral groove to provide localized reinforcement. This allows the groove to maintain large volume for water drainage while having specific rigid sections that prevent excessive deformation, balancing wet performance and structural integrity.

Inventive Principle:

Principle #3Local quality

2Reliability

If the volume of lateral groove is increased to improve wet performance, then water drainage capability is improved, but deformation of lateral groove is increased

Engineering Contradiction:

Improvewet performanceVSAvoidgroove deformation

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The lateral groove is divided into multiple segments by crown tie bars that protrude from the groove bottom. This segmentation maintains the overall groove volume for water drainage while creating rigid segments that resist deformation, thereby resolving the contradiction between wet performance and pattern rigidity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The crown tie bars are pre-positioned within the lateral groove to provide structural support before the tire encounters wet road conditions. This beforehand reinforcement prevents excessive groove deformation during operation, maintaining both drainage capability and structural stability.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If the lateral groove deforms during contact with ground, then water drainage is improved, but pumping sound is increased

Engineering Contradiction:

Improvewater drainageVSAvoidpumping sound

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The lateral groove is divided into multiple segments by crown tie bars that protrude from the groove bottom. This segmentation maintains the overall groove volume for water drainage while creating rigid segments that resist deformation, thereby resolving the contradiction between wet performance and pattern rigidity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The tire tread incorporates a composite structure combining the flexible rubber matrix with rigid crown tie bar elements. This composite design allows the groove to maintain water drainage capability while the rigid tie bar components suppress deformation-induced pumping sounds during ground contact.

Inventive Principle:

Principle #40Composite materials

Data Source

PatentUS10926585B2Tire with tie bars

Publication Date: 2021.02.23 SUMITOMO RUBBER INDUSTRIES LTD

AI summary

A tire comprises a tread portion provided with a first middle main groove, a second middle main groove, a crown longitudinal groove disposed between the first middle main groove and the second middle main groove, first crown lateral grooves connecting between the crown longitudinal groove and second middle main groove, and second crown lateral grooves connecting between the crown longitudinal groove and the second middle main groove. The first crown lateral grooves and the second crown lateral grooves are arranged so as to be misaligned with each other in the tire circumferential direction. The crown longitudinal groove is provided with at least one crown tie bar formed by raising a groove bottom of the crown longitudinal groove.