Tire Conductive Rubber Path for Static Discharge and Low Rolling Resistance
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Solution Overview
Problem
Existing tires face challenges in reducing rolling resistance while ensuring effective release of static electricity from vehicles to the ground, as decreasing carbon content in carcass rubber increases volume resistivity, potentially blocking conductive paths.
Innovation Solution
The tire incorporates a conductive rubber portion that penetrates the carcass ply, connecting the conductive portion and the chafer portion, allowing static electricity to be easily released to the ground regardless of the carcass ply's conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the amount of carbon contained in the carcass rubber is decreased to reduce rolling resistance, then the rolling resistance is reduced, but the volume resistivity of the carcass rubber increases and the conductive path from the bead portion to the tread surface portion may be blocked
Solution Approach 1:
A conductive rubber portion is introduced as an intermediary element to bridge the bead portion and the tread surface portion. This conductive rubber portion penetrates the carcass ply and provides a dedicated conductive path, mediating the electrical connection without requiring the carcass rubber itself to be conductive. The conductive rubber portion acts as a mediator that transfers static electricity from the bead portion through the tire structure to the tread surface portion, resolving the contradiction between reducing carbon content in carcass rubber and maintaining conductivity.
Solution Approach 2:
The tire structure is segmented into distinct functional zones: the carcass rubber (optimized for low rolling resistance with reduced carbon content), the conductive rubber portion (dedicated to electrical conductivity), and other structural components. This segmentation allows each component to perform its specific function optimally - the carcass rubber focuses on reducing energy loss while the conductive rubber portion handles the electrical conduction function that would otherwise require carbon in the carcass rubber.
2Loss of energy
If the amount of carbon contained in the carcass rubber is decreased to reduce rolling resistance, then the rolling resistance is reduced, but the conductivity of the carcass ply deteriorates
Solution Approach 1:
The conductive rubber portion serves as a mediator that handles the static electricity discharge function, allowing the carcass rubber to be optimized for low rolling resistance without carbon. The conductive rubber portion penetrates the carcass ply and provides a continuous conductive path from the bead portion through to the tread surface portion, enabling static electricity to be discharged to the ground even when the carcass rubber itself has poor conductivity.
3Reliability
If a conductive path is ensured through the carcass ply by maintaining carbon content, then static electricity can be released, but the rolling resistance increases
Solution Approach 1:
The tire structure is divided into functionally distinct components: the carcass rubber optimized for low rolling resistance with reduced carbon content, and a separate conductive rubber portion dedicated to electrical conductivity. This segmentation eliminates the need for the carcass rubber to contain high carbon levels, as the conductive rubber portion assumes the electrical conduction function. The result is that static electricity discharge reliability is maintained through the conductive rubber portion while rolling resistance is reduced through the low-carbon carcass rubber.
Solution Approach 2:
Different regions of the tire are assigned different material properties: the carcass rubber has low carbon content for low rolling resistance, while the conductive rubber portion has high carbon content or conductive additives for electrical conductivity. This local differentiation of material quality allows each region to perform its specific function optimally without compromise.
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 enables efficient release of static electricity to the ground while maintaining reduced rolling resistance by decreasing the amount of carbon in the carcass rubber.
Implementation Method 1
a conductive rubber portion (80), and wherein the conductive rubber portion (80) penetrates the carcass ply (51)
Data Source
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AI summary
An aspect of a tire of the present invention is a tire provided with a tread portion (11), a sidewall portion (12), and a bead portion (13), the tire includes a bead core (60) which is provided in the bead portion (13), a carcass ply (51) which covers at least a part around a core axis of the bead core (60), and a conductive rubber portion (80) which includes an embedded portion embedded in the carcass ply (51), and at least a part of the embedded portion is located on an outside in a tire radial direction in relation to the bead core (60).