Heavy Duty Tire Bead Insert Composition

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Solution Overview

Problem

Tires intended for heavy loads face reduced endurance due to thermal-chemical or thermal-oxidative ageing of internal annular inserts, which compromises cohesion and leads to potential cracks, despite efforts to balance cohesion and hysteresis through filler content adjustments.

Innovation Solution

A rubber composition for internal annular inserts in tire beads, comprising a polyisoprene elastomer matrix with a specific range of cis-1,4-enchainments, 43-55 phr of reinforcing inorganic filler with a BET surface of 155-185 m2/g, a coupling agent, and a vulcanization system, enhances cohesion and endurance while minimizing hysteresis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the content of reinforcing filler in the rubber composition is increased to improve cohesion, then the cohesion of the internal annular insert is improved, but the hysteresis of the rubber composition increases which generates excessive heating and reduces tire endurance

Engineering Contradiction:

Improvecohesion of internal annular insertVSAvoidhysteresis heating

Core Design Contradiction:

StrengthVSLoss of energy

Solution Approach 1:

The patent applies parameter changes by precisely controlling the reinforcing filler content within 20-40 phr and the elastomer molecular weight within 100,000-500,000 g/mol. These parameter optimizations resolve the contradiction by finding the sweet spot where sufficient cohesion is achieved without excessive hysteresis heating, thereby improving tire endurance.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials by formulating a specific rubber composition containing elastomers, reinforcing fillers (carbon black and/or silica), and other additives in controlled proportions. This composite approach allows balancing cohesion and hysteresis properties, resolving the technical contradiction between strength and energy loss.

Inventive Principle:

Principle #40Composite materials

2Loss of energy

If the content of reinforcing filler is decreased to reduce hysteresis and heating, then the hysteresis and heating are reduced, but the cohesion of the internal annular insert is insufficient which reduces tire endurance

Engineering Contradiction:

Improvehysteresis heatingVSAvoidcohesion of internal annular insert

Core Design Contradiction:

Loss of energyVSStrength

Solution Approach 1:

The patent resolves this contradiction through parameter changes by establishing the optimal range of reinforcing filler content (20-40 phr) and elastomer molecular weight (100,000-500,000 g/mol). These controlled parameters ensure adequate cohesion while minimizing hysteresis heating, thereby improving tire endurance.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials with a specifically formulated rubber composition containing elastomers, reinforcing fillers, and additives in controlled proportions. This composite structure achieves the right balance between cohesion and hysteresis, resolving the contradiction between strength and energy loss.

Inventive Principle:

Principle #40Composite materials

3Ease of operation

If the internal annular insert is subjected to deformations at each wheel turn, then the tire functions normally, but the deformations generate high heating which accelerates thermal-chemical and thermal-oxidative ageing, reducing cohesion and tire endurance

Engineering Contradiction:

Improvetire functionalityVSAvoidtire endurance

Core Design Contradiction:

Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The patent applies parameter changes by optimizing the rubber composition parameters including elastomer type, molecular weight distribution, and reinforcing filler content. These parameter optimizations reduce hysteresis heating during normal tire deformation cycles, slowing down thermal ageing and improving tire endurance while maintaining normal tire functionality.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite materials with a specifically designed rubber composition that includes elastomers, reinforcing fillers, and antioxidants. This composite formulation reduces heating during deformation and resists thermal-chemical ageing, resolving the contradiction between operational functionality and endurance.

Inventive Principle:

Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The proposed rubber composition significantly improves tire endurance by maintaining cohesion and reducing hysteresis, as demonstrated by a 50% increase in distance traveled before visible wear appears on the tire surface compared to control tires.

Implementation Method 1

a coupling agent for bonding the reinforcing inorganic filler to the elastomer

Methodology Applied

Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

a vulcanization system

Methodology Applied

Scientific EffectVulcanization: Chemical Bonding

Data Source

PatentUS10427476B2Tire for a heavy duty vehicle

Publication Date: 2019.10.01 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)

AI summary

A tire which is intended to bear heavy loads and the endurance of which is improved. The tire contains, in the bead region, at least one internal annular insert, the said insert having a rubber composition containing a polyisoprene elastomer, between 45 phr and 60 phr of a reinforcing filler containing from 43 to 55 phr of a reinforcing inorganic filler with a BET specific surface of between 155 and 185 m2/g, and a coupling agent for bonding the reinforcing inorganic filler to the elastomer.