Self-Sealing Tire Layer Stability Across Temperature Changes
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Solution Overview
Problem
Pneumatic tires with sealant layers face challenges in maintaining consistent sealing properties due to temperature-dependent viscosity changes and dimensional variations of the sealant, leading to inadequate sealing at extreme temperatures.
Innovation Solution
A pneumatic tire design with a sealant layer that maintains a low rate of thickness and width change across temperature variations, using a crosslinked adhesive sealant with specific viscosity ratios and a toluene insoluble component, and optionally an auxiliary sheet to prevent deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the viscosity of the sealant is lower, then the sealant easily flows into the through-hole and sealing properties are improved, but the sealant flows toward the tire center side due to heat and centrifugal force during travel, causing insufficient sealing when the through-hole deviates from the tire center region
Solution Approach 1:
The patent applies parameter changes by optimizing the viscosity of the sealant to a specific range (100 to 1000 Pa·s at 25°C) and controlling the viscosity ratio between different temperatures. This parameter optimization allows the sealant to have appropriate flow characteristics at operating temperature while maintaining position stability during tire travel, resolving the contradiction between sealing effectiveness and position stability.
2Stability of the object's composition
If the sealant has a high viscosity, then the flow of the sealant toward the tire center is prevented, but the sealant becomes difficult to flow into the through-hole, causing decreased sealing properties
Solution Approach 1:
The patent resolves this contradiction by precisely controlling the viscosity parameter within the range of 100 to 1000 Pa·s at 25°C and maintaining the viscosity ratio between 0°C and 50°C within 5 to 50. This parameter control enables the sealant to resist unwanted flow during travel while still being able to flow into through-holes for effective sealing.
3Manufacturing precision
If the thickness of the sealant layer is decreased, then the dimension change is reduced, but an adequate amount of the sealant is less likely to flow into the through-hole, reducing sealing effectiveness
Solution Approach 1:
The patent addresses this contradiction by optimizing the thickness of the sealant layer to within 3 mm of the tire inner surface and controlling the rate of change in thickness between temperatures to be 3% or less. This controlled thickness parameter ensures dimensional stability while maintaining sufficient sealant volume for effective through-hole sealing.
4Manufacturing precision
If the width of the sealant layer is decreased, then the dimension change is reduced, but the range in which the sealing properties can be exhibited becomes narrower
Solution Approach 1:
The patent resolves this contradiction by controlling the width of the sealant layer to be within 5 mm of the tire equatorial position and limiting the rate of change in width between temperatures to 3% or less. This parameter control maintains dimensional stability while ensuring adequate sealing coverage across the tire tread width.
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
Ensures effective sealing properties regardless of temperature conditions by minimizing sealant layer deformation and maintaining adequate sealant flow into punctures, even under significant temperature fluctuations.
Implementation Method 1
a sealant layer containing an adhesive sealant is provided at least on an inner surface of the tread portion
Implementation Method 2
when the sealant flows toward a tire center side due to the effects of heat and centrifugal force applied during travel
Data Source
AI summary
In the pneumatic tire including a sealant layer containing an adhesive sealant on an inner surface of a tread portion, when a thickness of the sealant layer at 0° C. is G0, a thickness of the sealant layer at 50° C. is G50, a width of the sealant layer at 0° C. is W0, and a width of the sealant layer at 50° C. is W50, a rate of change RG of thickness expressed by RG=(|G50−G0|/G0)×100 is set to 3% or less, and a rate of change RW of width expressed by RW=(|W50−W0|/W0)×100 is set to 3% or less.