Conductive Tire Crown Architecture for Static Discharge and Wear
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Solution Overview
Problem
Heavy construction plant tyres face challenges with static electricity buildup due to high resistivity elastomeric compounds, leading to potential electric shocks for occupants, interference with vehicle electronics, and accelerated tyre ageing, while also compromising wear resistance and operating temperature control.
Innovation Solution
A tyre design with a tread comprising electrically conductive elastomeric compounds, including a central portion with a silica-covered filler dispersion and edging rubbers with low electrical resistivity, forming a conductive pathway from the tread to the rim to discharge static charges, while maintaining wear resistance and optimal operating temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high resistivity elastomeric compounds are used in the tread, then wear resistance is improved, but static electricity buildup occurs leading to electric shocks and electronic interference
Solution Approach 1:
The tread is divided into different zones with different electrical properties: the central portion uses high resistivity compound for wear resistance, while the lateral portions (shoulders) use low resistivity compound for static discharge. This local differentiation allows each zone to fulfill its specific function without compromising the other.
Solution Approach 2:
The tread is segmented into multiple portions (central and lateral) with distinct elastomeric compounds. The central portion maintains high resistivity for wear resistance, while lateral portions provide conductive pathways for static discharge, creating a segmented functional architecture that resolves the contradiction.
2Strength
If high resistivity elastomeric compounds are used in the tread, then wear resistance is improved, but operating temperature control deteriorates
Solution Approach 1:
Different zones of the tread are assigned different thermal management functions: the central portion uses high resistivity material for wear resistance, while lateral portions use low resistivity materials that also provide better thermal dissipation, allowing localized temperature control throughout the tread structure.
3Object-generated harmful factors
If low resistivity elastomeric compounds are used in the tread, then static electricity discharge is improved, but wear resistance deteriorates
Solution Approach 1:
The lateral portions of the tread use low resistivity elastomeric compounds optimized for static discharge, while the central portion uses high resistivity compounds optimized for wear resistance. This spatial differentiation of material properties allows both functions to be optimized simultaneously in their respective zones.
4Object-generated harmful factors
If the tread is made entirely of electrically conductive material, then static electricity discharge is improved, but manufacturing complexity increases due to filler dispersion requirements
Solution Approach 1:
Rather than making the entire tread conductive (which would require uniform high-level filler dispersion throughout), the invention applies conductive material only to specific lateral portions where static discharge is needed. This reduces the overall manufacturing complexity and filler dispersion requirements while maintaining the essential static discharge function.
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 effectively reduces static electricity discharge, improves wear resistance, and maintains a controlled operating temperature, enhancing the tyre's endurance and reducing the risk of electric shocks and electronic interference.
Implementation Method 1
a reinforcing filler predominantly comprising a filler covered at least partially with silica, with a dispersion of the reinforcing filler in the elastomeric matrix having a Z score greater than or equal to 70
Implementation Method 2
The electrical resistivities of the elastomeric compound of said tread wing and of the elastomeric compound of the edging rubber of the protective layer, respectively, being at most equal to 106 a cm, such that the tread wing, the edging rubber of the protective layer, the elastomeric coating compounds of the protective layers, the working layers, the carcass layer and the bead layer, respectively, constitute a preferential conductive pathway for the electric charges between the ground and the rim
Implementation Method 3
each compound having a viscoelastic loss tgδ defined as being the ratio of the viscous shear modulus to the elastic shear modulus, the moduli being measured at a frequency of 10 Hz for a temperature of 60° C.
Data Source
AI summary
The compromise between the performance aspects of endurance and wear of a tyre for construction plant vehicles is improved, while limiting the mean operating temperature thereof to an appropriate level of around 100° C., and while ensuring its capacity of being electrically conductive, that is to say of discharging electrostatic charges that have built up during running. For this purpose, the tread comprises three parts: two electrically conductive tread wings and a central portion that is optimized in terms of hysteresis and is therefore not electrically conductive. The pathway for discharging electrostatic charges connects the tread wings to the rim, passing via electrically conductive edging rubbers positioned at the axial ends of the layers of the crown.