Tire Belt Layer Layout for Steering Stability and Durability

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Solution Overview

Problem

Tires with a belt layer, while achieving noise and fuel efficiency, face challenges in enhancing steering stability and durability to meet modern vehicle performance standards and infrastructure demands.

Innovation Solution

A tire design incorporating a belt layer with densely arranged non-twisted single steel wire belt cords and a band layer, optimized in terms of cord density, thickness, and arrangement to improve rigidity and reaction force generation, thereby enhancing steering stability and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a belt layer with conventional cord arrangement is used, then noise performance and low fuel consumption are achieved, but steering stability and durability are insufficient

Engineering Contradiction:
Improvesteering stability and durabilityVSAvoidbelt layer structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The belt layer is divided into multiple belt plies (first belt ply and second belt ply) with different cord arrangements. Each ply is further segmented into regions with different cord orientations (diagonal cords at 30-45 degrees in one region, circumferential cords in another region). This segmentation allows each segment to perform specific functions for optimizing both steering stability and durability without excessive overall complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the belt layer are assigned different cord arrangements based on local performance requirements. The diagonal cord region provides enhanced steering stability and shoulder durability, while the circumferential cord region optimizes for low fuel consumption and noise performance. This local quality differentiation resolves the contradiction by addressing specific performance needs in specific areas rather than uniform design.

Inventive Principle:
Principle #3Local quality

2Reliability

If belt cords are densely arranged to improve rigidity, then steering stability improves, but heat generation increases

Engineering Contradiction:
Improvesteering stabilityVSAvoidheat generation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The invention optimizes the density and arrangement parameters of belt cords to achieve the desired balance. By specifying precise cord angles (30-45 degrees for diagonal cords) and regional distribution patterns, the design achieves improved steering stability through optimized rigidity while controlling heat generation through appropriate cord spacing and orientation that reduces friction and stress concentration.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4201703B1tire
Publication Date: 2025.01.01 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4201703B1 patent drawingFigure 1
  • EP4201703B1 patent drawingFigure 2
  • EP4201703B1 patent drawing

AI summary

Provided is a tire having improved steering stability and durability. The tire 1 includes a belt layer 7 disposed inward of a tread portion 2 in a tire radial direction a. The belt layer 7 includes a first belt ply 7A. The first belt ply 7A includes belt cords 7a each formed of a single steel wire. A number N1 of belt cords 7a that are arranged per ply width of 5 cm in the first belt ply 7A is 102 to 187, in a cross section orthogonal to a longitudinal direction of the belt cords 7a.