Antistatic Tire Tread Using Thin Conductive Insert
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Solution Overview
Problem
Tires with silica-based tread portions face issues with static electricity accumulation due to poor conductivity, leading to discomfort for occupants, potential tire aging, and radio interference, while existing antistatic solutions compromise rolling resistance and durability.
Innovation Solution
A method involving extruding the tread layer, temporarily dividing it to create free surfaces, coating with a conductive rubber mixture, and rejoining before cooling, using a co-extruder with an elongated injection element to form a thin conductive insert that extends across the tread layer's thickness, ensuring antistatic properties without compromising other tire attributes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conductive rubber mixture insert is inserted in the tread portion to form conductive chimneys, then antistatic properties are improved, but rolling resistance and durability are worsened
Solution Approach 1:
The patent applies this principle by forming an extremely thin conductive insert (thickness of 0.01-0.2 mm) within the tread layer using a co-extrusion process. This thin conductive film provides the necessary electrical conductivity to dissipate static electricity while minimizing disruption to the tread layer's structural integrity and mechanical properties, thereby maintaining tire durability and rolling resistance performance.
Solution Approach 2:
The patent applies this principle by creating a composite structure that integrates a conductive rubber mixture (containing carbon black) into the tread layer. The co-extrusion process produces a multi-layer composite where the conductive insert is embedded within the tread rubber, combining the electrical conductivity of carbon black-filled rubber with the mechanical properties of the tread material to achieve both antistatic functionality and structural reliability.
2Object-affected harmful factors
If conductive chimneys extend from the ground contacting surface to the conductive base layer, then electrical conductivity is improved, but the tread layer is divided into separated sections compromising structural integrity
Solution Approach 1:
The patent applies this principle by transitioning from a three-dimensional conductive chimney structure that divides the tread layer to a two-dimensional thin conductive insert or layer. This dimensional reduction allows the conductive element to extend across the tread thickness without creating deep vertical channels that would segment and weaken the tread structure, thereby maintaining both electrical conductivity and structural integrity.
3Object-affected harmful factors
If a thick conductive insert is used to ensure conductivity, then antistatic properties are improved, but rolling resistance increases
Solution Approach 1:
The patent applies this principle by using an extremely thin conductive insert with a thickness of only 0.01-0.2 mm. This minimal thickness ensures sufficient electrical conductivity to dissipate static electricity while minimizing the insert's impact on the tire's rolling resistance, as the thin conductive layer creates minimal additional deformation and energy loss during tire rotation.
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 method provides effective antistatic properties with minimal impact on rolling resistance and durability, maintaining the integrity of the tire by forming an extremely thin conductive layer that ensures good conductivity and adhesion between layers.
Implementation Method 1
The conductive rubber mixture comprises a conductive rubber solution... forming an extremely thin conductive layer that ensures good conductivity... specific electrical resistance of higher than 10^8 ohm cm is considered poor conductivity
Implementation Method 2
a) extruding the tread layer rubber using an extruder provided with at least one extrusion screw... co-extruding the tread layer rubber and a conductive base layer rubber... through at least two flow channels
Data Source
Figure 1
Figure 2~3
AI summary
The invention relates to a method of manufacturing a tread layer of a tire, the tread layer comprising a rubber mixture and a conductive insert that extends across the thickness of the tread layer from the ground contacting surface of the tread layer to a conductive rubber layer arranged underneath the tread layer. The method comprises extruding the tread layer rubber using an extruder provided with at least one extrusion screw; temporarily dividing the extruded tread layer in the thickness direction thereof to produce free surfaces in the tread layer; coating the free surfaces with a conductive rubber mixture; and rejoining the free surfaces whereby the conductive rubber mixture forms the conductive insert. The invention further relates to a device for carrying out the method, and to a tire provided with thin conductive inserts to provide antistatic behavior.