Pneumatic Tire Tread Segmentation for Heat Management
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Solution Overview
Problem
Heavy duty truck tires experience significant heat buildup and increased operating temperatures due to high hysteresis in the tread compound, leading to reduced heat durability and increased rolling resistance, which in turn affects fuel efficiency.
Innovation Solution
A pneumatic truck drive tire design featuring a tread cap and undertread with specific rubber compositions, including polyisoprene, polybutadiene, styrene-butadiene rubber, and carbon black, optimized for tan delta, storage modulus, and tear strength, to reduce heat buildup and rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thick tread region cross-section is used in heavy duty truck tires, then load bearing capacity is improved, but heat buildup and operating temperature increase significantly
Solution Approach 1:
The tread is segmented into multiple layers with different rubber compositions: a tread cap layer with higher polyisoprene content for heat resistance, and a tread base layer with different composition for durability. This segmentation allows each layer to perform its specific function, managing heat buildup while maintaining load bearing capacity.
Solution Approach 2:
Different regions of the tread are assigned different rubber compositions tailored to their specific functional requirements. The tread cap uses a composition optimized for heat resistance and hysteresis reduction, while the tread base uses a composition optimized for mechanical durability and load bearing, creating local quality variations that resolve the contradiction.
2Loss of energy
If high hysteresis tread compound is used, then rolling resistance increases, but heat buildup is reduced
Solution Approach 1:
The rubber composition parameters are precisely controlled, with polyisoprene content in the tread cap ranging from 52-64 phr, polybutadiene from 22-27 phr, and styrene-butadiene from 13-21 phr. These parameter changes optimize the balance between hysteresis and heat generation, achieving lower rolling resistance without excessive heat buildup.
Solution Approach 2:
The tread uses a composite rubber composition combining multiple polymer types (polyisoprene, polybutadiene, styrene-butadiene) with carbon black fillers. This composite material structure allows optimization of both hysteresis and heat resistance properties that cannot be achieved with a single material, resolving the contradiction between rolling resistance and heat buildup.
3Temperature
If polyisoprene rubber content is increased in the tread cap, then heat resistance is improved, but tear strength may be reduced
Solution Approach 1:
The tread cap rubber composition is a composite of polyisoprene (52-64 phr), polybutadiene (22-27 phr), and styrene-butadiene (13-21 phr), along with carbon black (47-57 phr). This composite structure leverages the heat resistance of polyisoprene while the other components and carbon black reinforcement maintain adequate tear strength, resolving the contradiction between heat resistance and tear strength.
Solution Approach 2:
The tread cap layer is specifically designed with a rubber composition optimized for heat resistance, while the tread base layer has a different composition optimized for mechanical strength. This local quality differentiation allows the tread cap to focus on heat management while the tread base provides mechanical durability, resolving the contradiction.
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 design enhances durability and reduces rolling resistance, resulting in improved fuel efficiency and extended tire life by managing heat buildup and hysteresis effectively.
Implementation Method 1
Heat build up in a heavy duty tire tread (e.g. heavy duty truck tire tread) during the working of such heavy duty tires under load can be of sufficient magnitude to cause such heavy duty tires to operate at relatively high temperatures... Such heat buildup may also result from relatively high hysteresis in the tread compound
Implementation Method 2
the tread cap comprising a rubber composition comprising 100 part by weight, per 100 parts by weight of rubber (phr) of a rubber consisting of from 52 to 64 phr of polyisoprene rubber, from 22 to 27 phr of polybutadiene rubber, and from 13 to 21 phr of styrene-butadiene rubber; and 47 to 57 phr of carbon black
Data Source
Figure 1
AI summary
A pneumatic tire comprising a tread, the tread comprising a tread cap layer (2), a tread base layer (4), and a tread underlayer (3) disposed between the tread cap layer (2) and the tread base layer (4) is disclosed. The tread cap layer (2) comprises a rubber composition comprising 100 part by weight, per 100 parts by weight of rubber (phr) of a rubber comprising from 52 to 64 phr of a polyisoprene rubber, from 22 to 27 phr of a polybutadiene rubber, and from 13 to 21 phr of a styrenebutadiene rubber; and 47 to 57 phr of carbon black. The tread underlayer (3) comprises a rubber composition comprising 100 phr of a rubber comprising from 71 to 86 phr of a polyisoprene rubber and from 14 to 29 phr of a polybutadiene rubber; from 19 to 23 phr of silica; and from 29 to 36 phr of carbon black.