Heavy-Load Tire Bead Structure With Segmented Wire Chafer

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Conventional heavy-load tire bead structures struggle to maintain load-bearing performance without increasing tire deformation, leading to potential carcass breakage due to the deformation and rubbing against the bead core, especially with polygonal bead core shapes.

Innovation Solution

A tire design featuring a hexagonal bead core with a separated wire chafer configuration, including an upper side chafer and a lower side chafer, which minimizes deformation and load amplitude by preventing the carcass from being pushed against the bead core, thereby enhancing load-bearing performance and durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a wire chafer is provided on the outer circumference of the carcass to reinforce the bead portion, then the load bearing performance is improved, but the carcass is pressed against the bead core during deformation, causing rubbing and eventual breakage

Engineering Contradiction:

Improveload bearing performanceVSAvoidcarcass durability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The wire chafer is divided into an upper side wire chafer and a lower side wire chafer that are separated from each other. This segmentation prevents the wire chafer from continuously pressing the carcass against the bead core during tire deformation, reducing rubbing and the risk of carcass breakage while maintaining load bearing performance

Inventive Principle:

Principle #1Segmentation

2Force

If the load amount is increased without increasing the number of tires, then the load bearing performance per tire must be improved, but this increases the deformation amount of the ground-contacted part

Engineering Contradiction:

Improveload bearing performance per tireVSAvoiddeformation amount of ground-contacted part

Core Design Contradiction:

ForceVSShape

Solution Approach 1:

By separating the wire chafer into upper and lower sides, the structure allows controlled deformation during ground contact while preventing excessive carcass compression against the bead core. This enables the tire to handle larger loads with reduced harmful deformation

Inventive Principle:

Principle #1Segmentation

3Strength

If a polygonal bead core contour shape (square or hexagonal) is used, then the structural strength is improved, but the carcass is more easily rubbed by the top part of the bead core

Engineering Contradiction:

Improvebead core structural strengthVSAvoidcarcass rubbing and breakage risk

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The separated wire chafer configuration creates gaps between the upper and lower side chafers that prevent continuous contact with the carcass at the bead core corners. This reduces rubbing damage while allowing the use of strong polygonal bead core shapes

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The separated wire chafer acts as an intermediary that moderates the interaction between the carcass and the polygonal bead core, reducing direct rubbing contact at critical corners while maintaining structural support

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP3988344B1tire

Publication Date: 2024.11.20 BRIDGESTONE CORP

Figure 1
Figure 2A~2B
Figure 3~4

AI summary

A tire including: a pair of bead cores formed in a polygonal shape in cross-sectional view; a carcass toroidally straddling between the bead cores and folded back around the bead cores; and a wire chafer extending along the carcass so as to cover the carcass folded back around the bead cores from an inner side in a radial direction of a tire, in which, at a side on a tire inner circumference side of the bead core, the wire chafer is provided by being separated into an upper side wire chafer and a lower side wire chafer.