Self-Sealing Tire Sealant Layer Viscosity Segmentation

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Solution Overview

Problem

Self-sealing pneumatic vehicle tires face challenges in maintaining sealing effectiveness across varying temperatures, particularly at cold and hot conditions, and preventing sealant from flowing out after a puncture.

Innovation Solution

The tire features at least two layers of sealant with different viscosities, where the first layer has a higher viscosity than the second layer, arranged radially adjacent to each other, ensuring reliable sealing at different temperatures and preventing sealant from escaping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single layer of sealant is used, then the structure is simple, but the sealing effectiveness varies at different temperatures and sealant may flow out

Engineering Contradiction:
Improvesealing effectivenessVSAvoidsealant layer structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sealant system is divided into multiple layers with different viscosities. The first sealant layer (higher viscosity) is applied to the inner surface opposite the tread, while the second sealant layer (lower viscosity) is applied radially inside the first layer. This segmentation allows each layer to perform specific functions: the higher viscosity layer prevents sealant escape, while the lower viscosity layer ensures effective puncture sealing across temperature variations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the sealant system have different viscosities tailored to their specific functions. The first layer near the puncture site has higher viscosity to prevent sealant from flowing out, while the second layer has lower viscosity to maintain flowability and sealing effectiveness. This local quality differentiation resolves the contradiction between preventing sealant escape and maintaining sealing effectiveness.

Inventive Principle:
Principle #3Local quality

2Reliability

If sealant has high flowability to seal punctures effectively, then sealing performance is good, but sealant flows out of the tire especially at high temperatures

Engineering Contradiction:
Improvepuncture sealingVSAvoidsealant loss
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The sealant is segmented into two layers with different flow characteristics. The second layer (lower viscosity) provides the necessary flowability to seal punctures effectively, while the first layer (higher viscosity) acts as a barrier to prevent sealant from flowing out of the tire, thus resolving the contradiction between sealing performance and sealant retention.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The viscosity property is differentiated locally across the sealant layers. The region closer to the puncture site (second layer) has lower viscosity for effective sealing, while the region closer to the tire interior (first layer) has higher viscosity to prevent escape. This local quality approach allows the system to simultaneously achieve both objectives.

Inventive Principle:
Principle #3Local quality

3Loss of substance

If sealant viscosity is increased to prevent sealant escape, then sealant retention is improved, but sealing effectiveness at cold temperatures deteriorates

Engineering Contradiction:
Improvesealant retentionVSAvoidsealing at cold temperatures
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The sealant system is segmented into two layers with different viscosities. The second layer with lower viscosity ensures effective sealing at cold temperatures by maintaining adequate flowability, while the first layer with higher viscosity prevents sealant escape. This segmentation resolves the contradiction between sealant retention and cold temperature sealing effectiveness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different viscosity properties are assigned to different layers based on their functional requirements. The second layer near the puncture site has lower viscosity to ensure flowability and sealing effectiveness at cold temperatures, while the first layer has higher viscosity to prevent sealant escape, thus resolving the contradiction through local quality differentiation.

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 configuration maintains a good seal across a wide temperature range (-20°C to +45°C) and prevents sealant from flowing out after a puncture, even under high temperatures, ensuring effective sealing and mobility.

Implementation Method 1

the first and the second layer of sealant being the dynamic shear viscosity at 100 °C have different viscosities

Methodology Applied
Scientific EffectViscosity:

Implementation Method 2

each of which consists of a viscoelastic material

Methodology Applied
Scientific EffectViscoelasticity: Viscoelasticity

Data Source

PatentEP3743296B1Self-sealing vehicle pneumatic tyre comprising a sealant layer
Publication Date: 2023.06.14 CONTINENTAL REIFEN DEUTSCHLAND GMBH
  • EP3743296B1 patent drawingFigure 1

AI summary

The invention relates to a self-sealing vehicle pneumatic tyre comprising a sealant layer. According to the invention, the self-sealing vehicle pneumatic tyre comprises at least one first sealant layer arranged on the inner surface opposing the tread and at least one second sealant layer, the first and the second sealant layers being arranged radially adjacently in relation to each other, and the first and the second sealant layers comprising different sealants in terms of the dynamic shear viscosity at 100°C.