Bead Reinforcing Filler Layout for Tire Cornering and Vibration

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Solution Overview

Problem

Existing pneumatic tires face a challenge in improving cornering performance while maintaining vibration absorbing performance, particularly in motorcycle tires, as increasing rim tightening force leads to increased vibration when riding over road surface gaps.

Innovation Solution

A pneumatic tire design featuring a reinforcing filler with specific radial and axial extensions in the bead portions, including an inner, outer, and middle portion, positioned to enhance rim tightening force and suppress excessive rigidity, thereby improving cornering performance while maintaining vibration absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the rim tightening force is increased to improve cornering performance, then the cornering performance is improved, but the vibration when riding over road surface gaps increases

Engineering Contradiction:
Improvecornering performanceVSAvoidvibration
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The reinforcing filler is divided into three distinct portions (inner portion, middle portion, outer portion) with different spatial configurations. Each portion serves a specific function: the inner portion enhances rim tightening force for cornering performance, while the outer portion's extended radial position suppresses excessive rigidity to reduce vibration, achieving a segmented functional distribution that resolves the contradiction.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the bead portion are assigned different reinforcing filler configurations tailored to local requirements. The inner portion is positioned to maximize rim tightening force where cornering performance is needed, while the outer portion extends radially to provide flexibility where vibration absorption is required, implementing local quality optimization to balance performance and comfort.

Inventive Principle:
Principle #3Local quality

2Strength

If the reinforcing filler is positioned to increase rim tightening force, then the cornering performance is improved, but the vibration absorbing performance deteriorates

Engineering Contradiction:
Improverim tightening forceVSAvoidvibration absorbing performance
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The reinforcing filler structure is segmented into multiple portions with distinct spatial arrangements. The inner portion is configured to enhance rim tightening force for improved cornering performance, while the outer portion extends in the radial direction to suppress excessive rigidity, thereby maintaining vibration absorbing performance despite the presence of reinforcing elements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the bead portion receive tailored reinforcing filler configurations. The inner portion is positioned to maximize rim tightening force where cornering performance is critical, while the outer portion is arranged to provide flexibility and vibration absorption where needed, implementing local quality optimization to simultaneously achieve both objectives.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4434774B1Pneumatic tire
Publication Date: 2026.02.04 SUMITOMO RUBBER INDUSTRIES LTD
  • EP4434774B1 patent drawingFigure 1
  • EP4434774B1 patent drawingFigure 2
  • EP4434774B1 patent drawingFigure 3

AI summary

A pneumatic tire (1) includes a reinforcing filler (10) arranged along a bead core (5). The reinforcing filler (10) includes an inner portion (11) extending in the tire radial direction, outer portion (12) extending in the tire radial direction, and a middle portion (13) extending in the tire axial direction on the radially inner side of the bead core (5) so as to connect the inner portion (11) and the outer portion (12). The outer portion (12) has an outer end (12e) in the tire radial direction located radially inside an outer end (11e) in the tire radial direction of the inner portion (11) and located radially outside a center position (5c) of a section height (Ha) of the bead core (5) in the tire radial direction.