Conductive Tire Tread for Static Discharge via Localized Carbon Black
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Solution Overview
Problem
Conventional pneumatic tires lack effective electrical conductivity in their tread portions, leading to increased resistance and potential issues with static electricity discharge, which can affect performance and safety.
Innovation Solution
Incorporating an electrically conductive tread portion made from a specific rubber composition, including styrene butadiene rubber, butadiene rubber, and natural rubber with carbon black, positioned between low conductive tread portions to create a path of reduced electrical resistivity from the bead region to the ground contact surface, utilizing multiple layers of electrically conductive rubber strips to enhance conductivity without compromising tire properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tread portion is made of conventional rubber composition, then the tire maintains good fatigue resistance and handling properties, but the electrical resistance through the tread is high and static electricity discharge is ineffective
Solution Approach 1:
The tread portion is designed with non-uniform electrical conductivity: the central circumferential region contains conductive filler (carbon black or metal particles) to provide low electrical resistance for static discharge, while the radial edge regions maintain conventional rubber composition for optimal fatigue resistance and handling. This local differentiation allows simultaneous achievement of electrical conductivity and mechanical strength.
2Reliability
If carbon black content is increased to improve electrical conductivity, then electrical resistance decreases, but the rubber composition properties and tire performance may be compromised
Solution Approach 1:
High carbon black content (5-20 parts by weight per 100 parts rubber) is applied only in the central circumferential region of the tread where electrical conductivity is needed, while the radial edge regions use conventional carbon black content (1-3 parts by weight per 100 parts rubber) to maintain optimal rubber composition properties for fatigue resistance and handling.
Solution Approach 2:
The tread portion uses a composite rubber composition combining conventional rubber (natural rubber, styrene-butadiene rubber, or butadiene rubber) with conductive fillers (carbon black or metal particles such as stainless steel, aluminum, or copper). This composite approach enables the tread to simultaneously exhibit elastic properties of rubber and electrical conductivity of the filler materials.
3Reliability
If metal particles are used instead of carbon black for conductivity, then electrical conductivity is enhanced, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent provides flexibility in selecting conductive fillers based on performance requirements: carbon black (simpler, cheaper) for moderate conductivity needs, or metal particles (stainless steel, aluminum, copper) for enhanced conductivity. The formulation parameters including filler type, content (5-20 parts per 100 parts rubber), and particle size can be adjusted to balance conductivity performance with manufacturing complexity and cost.
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 solution significantly reduces electrical resistance through the tire, allows for efficient static electricity discharge to the ground, and maintains the tire's other performance characteristics such as fatigue resistance and handling properties.
Implementation Method 1
The electrically conductive tread portion extends through the tread, i.e., from a first electrically conductive rubber layer, which can be disposed below the tread portions, to the ground contacting surface of the tire. Thus, resistance through the tread of the tire can be decreased.
Implementation Method 2
The tire can comprise an electrically conductive tread portion that extends through the tread, thereby resistance through the tread of the tire can be decreased, allowing for efficient static electricity discharge to the ground.
Data Source
Figure 1a~1b
Figure 2~5
Figure 3a~3f
AI summary
The invention relates to a method for producing a tread (120) of a pneumatic tire (100), the pneumatic tire (100) comprising a first sidewall (145a), and a second sidewall (145b), wherein the tread has a ground contacting surface formed of tread portions (120a, 120b, 10). The method comprises: forming a first electrically conductive rubber layer (115), the first electrically conductive rubber layer (115) comprising first electrically conductive rubber material, winding a first uncured electrically low conductive rubber strip on a first area of the first electrically conductive rubber layer (115) in order to form at least part of a first uncured electrically low conductive tread portion, winding an uncured electrically conductive rubber strip (121) on a second area of the first electrically conductive rubber layer (115) in order to form an uncured electrically conductive tread portion, which extends to the ground contacting surface of the tread, which uncured electrically conductive tread portion comprises one or more than one layer of the uncured electrically conductive rubber strip, winding a second uncured electrically low conductive rubber strip on a third area of the first electrically conductive rubber layer (115) in order to form at least part of a second uncured electrically low conductive tread portion, and vulcanizing said windings, thereby obtaining the tread (120) of the pneumatic tire, the tread (120) comprising the electrically conductive tread portion (10), the first low conductive tread portion (120a), and the second low conductive tread portion (120b). The invention further relates to a pneumatic tire.