Pneumatic Tire Sealant Layer Profile for Centrifugal Stability

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Solution Overview

Problem

Pneumatic tires with existing puncture-sealing technologies face challenges in maintaining effective sealant distribution and preventing air leakage, especially under centrifugal forces during tire rotation, which can lead to insufficient sealing at the tire edges and loss of steering control on rough surfaces.

Innovation Solution

A pneumatic tire design featuring an inner-liner layer made of air-impermeable rubber with a specific profile and a sealant layer adhered to its inner-side surface, where the sealant layer's profile satisfies L1 < L2 < L3, L1 ≤ 5 mm, L2 ≤ 9.5 mm, and L3 ≤ 11 mm, and is laminated with a foamed body to enhance puncture-sealing capability and maintain sealant position.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sealant layer is coated on the cavity side of the tire tread section, then puncture-sealing capability is improved, but sealant distribution becomes insufficient at tire edges under centrifugal forces

Engineering Contradiction:
Improvepuncture-sealing capabilityVSAvoidsealant distribution
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies different properties to different parts of the sealant layer by controlling its thickness distribution. The sealant layer is made thicker at the tire edges (where L1, L2, L3 measurements are taken) and can be thinner in the center, creating local quality variations that ensure adequate sealant coverage at critical edge positions while maintaining overall effectiveness.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The sealant layer is pre-applied to the inner-liner layer before tire assembly and inflation. This preliminary action ensures that the sealant is already in position and properly distributed according to the designed thickness profile (L1, L2, L3 specifications) before the tire enters service, preventing sealant migration or insufficient coverage during operation.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the sealant layer is adhered to the inner-liner layer, then air leakage is prevented, but steering control is lost on rough surfaces due to insufficient sealant coverage

Engineering Contradiction:
Improveair leakage preventionVSAvoidsteering control
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent ensures adequate sealant coverage at specific locations (edge positions measured by L1, L2, L3) while allowing different thickness in other areas. This local quality approach maintains air leakage prevention at critical positions without excessive sealant that could affect steering control on rough surfaces.

Inventive Principle:
Principle #3Local quality

3Quantity of substance

If the sealant layer width is increased beyond the belt layer width, then sealant coverage is improved, but centrifugal force causes sealant flow and redistribution

Engineering Contradiction:
Improvesealant coverageVSAvoidsealant position stability
Core Design Contradiction:
Quantity of substanceVSStability of the object's composition

Solution Approach 1:

The patent creates a sealant layer with non-uniform thickness distribution, making it locally thicker at the edges (L1, L2, L3 positions) and potentially thinner in the center. This local quality variation provides adequate coverage at critical positions while the overall width matches the belt layer, reducing excessive material that would migrate under centrifugal force.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent specifies precise thickness parameters (L1, L2, L3 with maximum values of 5mm, 9.5mm, and 11mm respectively) to control the sealant layer's physical dimensions. By changing and controlling these dimensional parameters, the design ensures adequate coverage while limiting the total amount of sealant material that could flow under centrifugal influence during tire rotation.

Inventive Principle:
Principle #35Parameter changes

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 tire achieves excellent puncture-sealing performance while preventing air leakage and maintaining steering stability on rough road surfaces by suppressing sealant flow and ensuring adequate sealant coverage across the tire width, even under centrifugal forces.

Implementation Method 1

a sealant layer adhered to a radially inner-side surface of the inner-liner layer

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

a viscous sealant is coated in advance on the cavity side of the tire tread section... the sealant deforms to fill the puncture

Methodology Applied
Scientific EffectViscosity: Viscometer

Data Source

PatentEP3406464B1Pneumatic tire
Publication Date: 2020.05.13 SUMITOMO RUBBER INDUSTRIES LTD
  • EP3406464B1 patent drawingFigure 1
  • EP3406464B1 patent drawingFigure 2
  • EP3406464B1 patent drawingFigure 3

AI summary

A pneumatic tire (1) includes a a tread (2); side walls (3), beads (4), a carcass (6), a belt layer (7), and an inner-liner layer (9), and a sealant layer (10); the inner-side surface of the inner-liner layer (9) to which the sealant layer (10) is adhered has a profile that satisfies L1 &lt; L2 &lt; L3, L1 &lt; 5 mm, L2 &lt; 9.5 mm, and L3 &lt; 11 mm, where L1, L2 and L3 represent heights in a radial direction measured from a base height point to the inner-side surface of the inner-liner layer (9) at positions located in an axially inward direction from an axial outer edge (7e) of the belt layer (7) by 5%, 10% and 15% of a maximum width (Wa) of the belt layer (7), and the base height point is a point on an axial-direction line that passes through the intersection where a radial-direction line passing through the axial outer edge (7e) of the belt layer (7) intersects the inner-side surface of the inner-liner layer (9); and a foamed body is laminated on the tire radially inner side surface (10a) of the sealant layer (10)