Motorcycle Tire Cord Density Distribution for Handling

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Solution Overview

Problem

Conventional motorcycle tires face challenges in achieving high stiffness and excellent handling performance due to uneven holding forces across the belt structure, particularly on the shoulder side, which affects the tire's ability to maintain stability during turns.

Innovation Solution

A motorcycle tire design featuring a tread reinforcing layer with a crown region and shoulder regions, where the distance between reinforcing cords is reduced in the shoulder regions compared to the crown region, ensuring a higher number of cords per unit periphery length in the crown region while maintaining reduced distances between cords in the shoulder regions, thereby distributing forces more evenly and enhancing stiffness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the cord coils are wound with the same circumferential length, then the manufacturing process is simple, but the holding force difference between inner and outer sides increases on the shoulder side, reducing belt structure stiffness

Engineering Contradiction:
Improvecord coil winding processVSAvoidbelt structure stiffness
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent applies local quality by differentiating the cord coil configuration between the crown region and shoulder region. Specifically, the number of cord coils per unit axial length is made greater in the shoulder region than in the crown region, creating localized structural differences that compensate for the curved tread geometry and achieve uniform holding forces across different tire regions.

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If the number of cord coils per unit axial length is increased in the shoulder region, then the holding force uniformity improves, but the manufacturing complexity increases

Engineering Contradiction:
Improveholding force uniformityVSAvoidbelt structure configuration
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent implements local quality by creating region-specific cord coil densities. The shoulder region is designed with a higher number of cord coils per unit axial length compared to the crown region, which locally compensates for the geometric effects of the curved tread and achieves uniform holding forces without requiring complete redesign of the entire belt structure.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3711980B1Motorcycle tire
Publication Date: 2021.01.27 SUMITOMO RUBBER INDUSTRIES LTD
  • EP3711980B1 patent drawingFigure 1
  • EP3711980B1 patent drawingFigure 2
  • EP3711980B1 patent drawingFigure 3(a)~3(b)

AI summary

Provided is a tire that can improve handling performance. A motorcycle tire 1 includes a tread portion 2 that is curved into an arc shape that projects outward in a tire radial direction. The tread portion 2 includes a carcass 6 and a tread reinforcing layer 7. The tread reinforcing layer 7 is formed by helically winding a rubber-coated cord strip 10. The tread reinforcing layer 7 includes a crown region Cr and shoulder regions Sh. The rubber-coated cord strip 10 includes a plurality of reinforcing cords 11 aligned with each other. A distance Ws between the reinforcing cords 11 and 11 which are adjacent to each other in the rubber-coated cord strip 10 wound in the shoulder region Sh is less than a distance Wc between the reinforcing cords 11 and 11 which are adjacent to each other in the rubber-coated cord strip 10 wound in the crown region Cr.