Conductive Carcass Ply Thread for Low-Resistance Pneumatic Tires
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Solution Overview
Problem
Existing pneumatic tires with conductive fibers break due to deformation, leading to increased electrical resistance and reduced ride quality, especially when encountering curbs, and they inhibit sidewall deflection.
Innovation Solution
A pneumatic tire design with a conductive thread having an electrical resistance of 108 Ω/cm or less and a stress of 13 N or less at 1% elongation, integrated into the carcass ply, which extends from the bead to the tread portion, to prevent breakage and maintain low electrical resistance and ride comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If composite fibers containing metal conductive fibers are arranged on the surface of the carcass to reduce electrical resistance, then the electrical resistance of the tire is reduced, but the conductive fibers break due to repeated deformation and local deformation when the tire runs over bumps or curbs
Solution Approach 1:
The patent changes the key parameter of stress at 1% elongation to 13 N or less, which is significantly lower than conventional conductive fibers. This parameter change allows the conductive thread to elongate more easily during tire deformation without breaking, while still maintaining sufficient electrical conductivity (108 Ω/cm or less).
Solution Approach 2:
The conductive thread is formed as a composite material combining conductive fibers (metal or carbon) with non-conductive fibers (polyester, polyamide, or rayon). This composite structure provides both electrical conductivity and improved durability, with the non-conductive fibers contributing to tensile strength and flexibility while the conductive fibers maintain low electrical resistance.
2Reliability
If metal conductive fibers with high modulus are used to reduce electrical resistance, then the electrical resistance is reduced, but they inhibit sidewall deflection during rolling which deteriorates ride quality
Solution Approach 1:
The patent changes the modulus parameter by selecting conductive fibers with lower modulus values and combining them with non-conductive fibers having appropriate mechanical properties. This results in a conductive thread that is flexible enough to allow sidewall deflection during rolling, improving ride comfort, while still maintaining the required electrical conductivity through the conductive fiber component.
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 design effectively suppresses conductive thread breakage, maintains low electrical resistance, and enhances ride comfort by allowing moderate elongation during tire deformation.
Implementation Method 1
the conductive thread has an electrical resistance of 108 Ω/cm or less per unit length
Implementation Method 2
the conductive thread has a stress of 13 N or less at 1% elongation
Data Source
AI summary
A pneumatic tire has a carcass. The carcass includes a carcass ply extending from one bead portion to the other bead portion through a tread portion. The carcass ply is provided with at least one conductive thread extending from one bead portion to at least the tread portion. The conductive thread has an electrical resistance of 108 Ω/cm or less per unit length. The conductive thread has a stress of 13 N or less at 1% elongation.