Pneumatic Tire Conductive Layer for Static Charge Release
Solution Overview
Problem
Pneumatic tires with high silica content tread rubber experience issues with static charge release due to high electrical resistance, leading to radio noise problems, and existing conductive layer solutions fail to maintain functionality from the initial stage of wear due to sheathing during the curing process.
Innovation Solution
A pneumatic tire design featuring a conductive layer extending from the tread surface to the inner periphery with branch portions exposed to the tread surface, preventing sheathing and ensuring reliable static charge release from the initial stage of wear, regardless of the exposed location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conductive layer is formed within non-conductive tread rubber to release static charge, then radio noise problems are solved, but the conductive layer may be covered by non-conductive rubber during curing process causing sheathing
Solution Approach 1:
The conductive layer is divided into multiple segments (first conductive layer and second conductive layer) positioned at different locations within the tread rubber. This segmentation ensures that at least one conductive layer segment remains exposed to the tread surface after curing, preventing complete sheathing and maintaining static charge release functionality.
Solution Approach 2:
Different regions of the tread rubber are designed with different properties: the center portion and mediate portion have conductive layers positioned deeper to avoid exposure, while the shoulder portion has conductive layers positioned closer to the surface to ensure exposure. This local quality differentiation ensures that the conductive layer is exposed in at least one location while maintaining flexibility in pattern design.
2Reliability
If the conductive layer is exposed in the center portion or mediate portion, then static charge release is maintained, but the tread pattern design flexibility is limited
Solution Approach 1:
The patent applies different conductive layer positioning strategies to different local regions: center and mediate portions use deeper positioning to avoid sheathing, while shoulder portions use shallower positioning to ensure exposure. This allows flexible tread pattern design in any region without compromising static charge release functionality.
Solution Approach 2:
By dividing the conductive layer into multiple segments at different positions and depths, the patent allows the tread pattern to be designed freely in any region while ensuring that at least one conductive segment remains exposed to maintain static charge release function.
3Loss of energy
If silica is blended at high ratio in tread rubber to reduce rolling resistance, then fuel consumption is reduced, but electric resistance increases preventing static charge release
Solution Approach 1:
The patent creates a composite structure combining non-conductive tread rubber (with high silica content for low rolling resistance) and conductive rubber layers (for static charge release). The conductive layers are embedded within the non-conductive tread rubber, allowing the bulk material to maintain low rolling resistance while the conductive segments provide static charge release pathways.
Solution Approach 2:
The tire structure is segmented into non-conductive regions (tread rubber with high silica for low rolling resistance) and conductive regions (conductive layers for static charge release). This segmentation allows the tire to simultaneously achieve low rolling resistance through the non-conductive tread rubber and static charge release through the embedded conductive layers.
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 tire effectively releases static charge to the road surface through the conductive layer, maintaining functionality and preventing radio noise issues from the outset, while allowing for flexible pattern design and maintaining conductivity up to the end of the tire's wear life.
Implementation Method 1
a conductive layer extending from a tread surface to a bottom surface or side face of the non-conductive rubber layer through the non-conductive rubber layer, wherein the conductive layer has a main portion extending from the tread surface toward the inner periphery of the tire and a plurality of branch portions branched from the main portion and extending toward the outer periphery of the tire, and at least one of the branch portions is exposed to the tread surface
Data Source
AI summary
A pneumatic tire according to the invention includes a cap rubber 12 as a non-conductive rubber layer and a conductive layer 13 that extends from the tread surface to the bottom surface of the cap rubber 12 through the cap rubber 12. The conductive layer 13 has a main portion 13a extending from the tread surface toward the inner periphery of the tire, and plural branch portions 13b branched from the main portion 13a and extending toward the outer periphery of the tire. At least, one of the branch portions 13b is exposed to the tread surface.