Commercial Vehicle Tyre Tread Base Segmentation

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Solution Overview

Problem

Commercial vehicle tires face challenges in reducing rolling resistance while maintaining abrasion properties and ensuring electrical conductivity to dissipate static charges, as existing solutions often compromise on conductivity due to the use of low-hysteresis rubber mixtures in the tread.

Innovation Solution

The tire design features a tread base with a rubber mixture containing silica as a filler, which has a dynamic stiffness at least 10% lower than the tread cap, and non-conductive side walls with a carbon center beam for electrical charge dissipation, ensuring reduced rolling resistance without affecting abrasion properties and conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the tread cap is made from a soot-filled rubber mixture to ensure good abrasion properties, then the abrasion resistance is improved, but the rolling resistance increases

Engineering Contradiction:
Improveabrasion resistanceVSAvoidrolling resistance
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The tread is divided into two distinct parts: a tread cap made from soot-filled rubber mixture for abrasion resistance, and a tread base made from silica-filled or low-soot rubber mixture for low rolling resistance. This segmentation allows each part to optimize its function independently, resolving the contradiction between abrasion resistance and rolling resistance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the tread are assigned different material properties: the tread cap (outer region) uses soot-filled rubber for high abrasion resistance, while the tread base (inner region) uses silica-filled or low-soot rubber for low rolling resistance. This local differentiation of material quality enables simultaneous optimization of both contradictory requirements.

Inventive Principle:
Principle #3Local quality

2Loss of energy

If silica is used as filler in the tread base to reduce rolling resistance, then the electrical resistance increases and the tread becomes electrically non-conductive, but the rolling resistance is reduced

Engineering Contradiction:
Improverolling resistanceVSAvoidelectrical conductivity
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

A carbon center beam acts as an intermediary conductive element between the non-conductive tread base (made with silica for low rolling resistance) and the conductive tread cap. This mediator provides the necessary electrical conductivity path without requiring the entire tread base to be conductive, thus resolving the contradiction between rolling resistance reduction and electrical conductivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrical conductivity function is separated from the tread base material itself and assigned to a dedicated carbon center beam component. This segmentation allows the tread base to use silica-filled non-conductive rubber for low rolling resistance, while the carbon center beam provides the necessary electrical conductivity through a separate conductive pathway.

Inventive Principle:
Principle #1Segmentation

3Loss of energy

If the tread base is made from rubber mixtures with dynamic stiffness at least 10% lower than the tread cap, then the rolling resistance is reduced, but the structural support may be compromised

Engineering Contradiction:
Improverolling resistanceVSAvoidstructural support
Core Design Contradiction:
Loss of energyVSStrength

Solution Approach 1:

The tread base uses rubber mixtures with specifically optimized lower dynamic stiffness (at least 10% lower than the tread cap) to reduce rolling resistance, while the tread cap maintains higher stiffness for structural support. This local differentiation of stiffness properties allows the system to optimize rolling resistance without compromising overall structural integrity, as each layer performs its specific mechanical function.

Inventive Principle:
Principle #3Local quality

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

This design effectively reduces overall rolling resistance while maintaining good abrasion properties and ensuring electrical conductivity, allowing for efficient dissipation of static charges without compromising tire performance.

Implementation Method 1

Low hysteresis is achieved by using low-activity fillers, in particular by using a small amount of active filler, such as carbon black, and/or replacing carbon black with silicon dioxide (silica, silica)

Methodology Applied
Scientific EffectHysteresis: Hysteresis

Implementation Method 2

The electrical connection between the tread cap and the electrically conductive rubber layer of the belt is made by means of another strip made of a conductive rubber mixture, which passes through the tread base

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2452837B1Commercial vehicle tyres
Publication Date: 2016.11.09 CONTINENTAL REIFEN DEUTSCHLAND GMBH
  • EP2452837B1 patent drawingFigure 1

AI summary

The tire has a multi-layered belt (2) and a tread (1) that includes a radial inner tread base (7), which is formed from electrically non-conductive rubber composite containing silica, and a radial outer tread cap (6), which is formed from soot-filled rubber composite. Dynamic rigidity of the rubber composite of the base is smaller around 10 percent than that of the composite of the cap. Side walls (5) are formed from electrically non-conductive rubber composite filled with silica. A carbon center beam (9) is arranged in the base and connects a sub-structure with the cap.