Tire Conductive Member Overlap for Static Discharge Path
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Solution Overview
Problem
Tires face difficulty in releasing static electricity from the vehicle to the road surface due to increased electrical resistance when carbon content in coating rubber is reduced to decrease rolling resistance, causing a blockage of the conductive path by carcass plies.
Innovation Solution
Incorporating a conductive member with a rubber chafer and bead filler configuration, where the conductive member's radial inner end is positioned at the radial outer end of the rubber chafer or inward, and an overlap width of 1 mm or more is maintained between the conductive member and the rubber chafer to ensure electrical contact and path for static electricity release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the amount of carbon in the coating rubber is reduced to decrease the loss tangent, then the rolling resistance is reduced, but the electrical resistance of the coating rubber increases and the conductive path is blocked
Solution Approach 1:
A conductive member is introduced as an intermediary element between the bead portion and the road surface to establish a dedicated electrical conduction path. This mediator bypasses the need for the coating rubber to provide conductivity, allowing the rubber to focus on its primary function of reducing rolling resistance while the conductive member handles the electrical conduction task.
Solution Approach 2:
The electrical conduction function is separated from the coating rubber by introducing a distinct conductive member. This segmentation allows each component to specialize: the coating rubber optimizes for low rolling resistance with reduced carbon content, while the conductive member provides the necessary electrical conductivity through its own material composition and structural design.
2Reliability
If a conductive member is added to improve static electricity release, then the electrical conductivity is improved, but the device complexity increases
Solution Approach 1:
The conductive member is designed to serve multiple functions simultaneously: it provides electrical conduction from the bead portion to the road surface, acts as a structural reinforcement element in the tire's bead region, and maintains positional stability during tire operation. This multi-functionality reduces the need for additional separate components.
Solution Approach 2:
The conductive member is integrated into the existing tire structure by combining it with the bead filler and rubber chafer components. Rather than being a completely separate addition, the conductive member is merged with these existing elements to form a unified assembly that provides both structural and electrical functions within the same structural framework.
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 effectively allows for the easy release of static electricity from the vehicle to the road surface while maintaining reduced rolling resistance and minimizing weight increase by using lightweight conductive fiber members.
Implementation Method 1
a tire including: a pair of bead cores embedded in a pair of bead portions; a bead filler disposed on a tire radial outer side of the bead cores; and a rubber chafer disposed on a tire widthwise outer side of the bead filler, wherein the tire further includes a conductive member
Data Source
AI summary
In a tire of the present disclosure, an overlap width, between a conductive member and a rubber chafer, in an extending direction of the conductive member is 1 mm or more. A method of manufacturing a tire of the present disclosure includes vulcanizing a raw tire in a state such that an overlap width, between a conductive member and a rubber chafer before vulcanization, in an extending direction of the conductive member is 10 mm or more. In a raw tire of the present disclosure, an overlap width, between a conductive member and a rubber chafer before vulcanization, in an extending direction of the conductive member is 10 mm or more.