Conductive Cord Sidewall Extrusion for Tire Electrostatic Discharge
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Solution Overview
Problem
Pneumatic vehicle tires with silica-filled rubber mixtures in the sidewalls and tread exhibit low electrical conductivity, leading to electrostatic charge issues during driving, necessitating the integration of electrically conductive passages between the tire rim and tread without disrupting the existing production processes.
Innovation Solution
A method where an electrically conductive cord or strip is extruded and applied to the sidewall material web in a wavy shape during transport, ensuring contact with the conductive tread part and rim profile, forming conductive passages with minimal additional machinery investment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If silica-filled rubber mixtures are used in sidewalls and tread, then rolling resistance is reduced, but electrical conductivity deteriorates
Solution Approach 1:
The tire structure is segmented into electrically non-conductive sidewalls (with silica) and electrically conductive components (carbon black-filled tread and conductive passages). This segmentation allows each part to have optimized properties: silica for low rolling resistance in sidewalls, and carbon black for electrical conductivity in specific zones where charge discharge is needed.
Solution Approach 2:
Electrical conductivity is not uniformly distributed but localized to specific areas: the tread base, conductive passages in sidewalls, and horn profiles. This local quality approach maintains low rolling resistance overall while providing targeted electrical conductivity where electrostatic charge discharge is required.
2Reliability
If electrically conductive passages are integrated into sidewalls, then electrostatic charge discharge is enabled, but production process complexity increases
Solution Approach 1:
The conductive passages are formed during the sidewall extrusion process itself, before the tire assembly begins. The extruder is equipped with additional nozzles that deposit conductive rubber material directly into cavities formed in the sidewall material web, creating the conductive passages as an integrated part of the sidewall structure.
Solution Approach 2:
The formation of conductive passages is merged with the sidewall extrusion process. The same extruder that forms the sidewall also creates the conductive passages by depositing conductive material into pre-formed cavities, eliminating the need for separate post-processing steps to create the passages.
3Reliability
If conductive passages are formed after sidewall extrusion, then conductivity is achieved, but production time and investment increase
Solution Approach 1:
Cavities for the conductive passages are formed during the sidewall extrusion process itself, using the extruder to create recesses in the material web. The conductive material is then deposited into these pre-formed cavities in the same continuous production line, avoiding separate post-processing steps.
Solution Approach 2:
The sidewall extrusion and conductive passage formation occur in a continuous process on the same production line. The extruder continuously forms sidewalls with integrated cavities and deposits conductive material, maintaining continuous production flow without interruption or additional processing stages.
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 method allows for the simple integration of electrically conductive passages into the tire sidewalls, effectively addressing electrostatic charge issues while maintaining the existing production sequence with low machinery outlay, ensuring reliable conductivity through the corrugated shape and adhesive application.
Implementation Method 1
a cord 3 or a strip 3a made of an electrically conductive rubber mixture is extruded and applied to the sidewall material web 1 in a wavy shape
Data Source
Figure 1~2
AI summary
The invention relates to a method for producing electrically conductive passages in an electrically non-conductive sidewall of a vehicle pneumatic tire, wherein the electrically conductive passages run between an electrically conductive tread section, which is in electrically conductive contact with the outer surface of the tread, and the electrically conductive rim profile that comes into contact with a rim. After extrusion, the material web (1) is transported on a conveyor with its side forming the inner surface of the sidewall as the top surface. An electrically conductive rubber compound is used to extrude a cord (3) or a strip, which, during transport of the extruded material web (1), is applied to the top surface of the material web (1) in a wave-like form such that the conductive sections formed by the cord (3) or strip are present in the finished tire.The electrically conductive passages formed on the inside of the side wall are in contact with the electrically conductive tread section and the horn profile alternately in the areas of maximum deflection of the waveform.