Pneumatic Tire Tread-Belt Structure for Low Rolling Resistance
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Solution Overview
Problem
Existing tire designs that reduce rolling resistance tend to deteriorate ride comfort by transmitting small vibrations to the vehicle body.
Innovation Solution
A pneumatic tire design with a specific product (T1 x T2 x La x tanδ1) range of 0.33 to 1.10, incorporating a reinforcing cord layer with steel cords and a tread rubber layer, where T1 is tread rubber thickness, T2 is belt ply thickness, La is land ratio, and tanδ1 is loss tangent, to balance rolling resistance and ride comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the volume of tread rubber is reduced or the loss tangent of tread rubber is decreased to reduce rolling resistance, then rolling resistance performance is improved, but small vibrations during running are transmitted to the vehicle body and ride comfort is deteriorated
Solution Approach 1:
The invention changes the physical and chemical parameters of the rubber compounds used in different tire layers. Specifically, it uses rubber compounds with different loss tangent values for the tread rubber layer and cap rubber layer, optimizing the balance between rolling resistance and vibration absorption. The tread rubber layer uses compounds with lower loss tangent to reduce rolling resistance, while the cap rubber layer uses compounds with higher loss tangent to absorb vibrations.
Solution Approach 2:
The invention employs composite material structures with multiple rubber layers having different properties. The tread portion consists of tread rubber layer and cap rubber layer with different rubber compound formulations, creating a composite structure that simultaneously achieves low rolling resistance and good vibration absorption. The steel cord layer with specific cord structure also contributes to the composite structure for balancing performance.
2Loss of energy
If the volume of belt layer is reduced to reduce rolling resistance, then rolling resistance performance is improved, but structural strength and vibration absorption may be compromised
Solution Approach 1:
The invention optimizes the parameters of the steel cords in the belt layer, specifically using steel cords with outer diameter of 0.15 to 0.30 mm and 1 x n cord structure. This parameter optimization allows the belt layer to maintain sufficient strength while reducing overall volume and rolling resistance.
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
Improves rolling resistance without deteriorating ride comfort by optimizing the product (T1 x T2 x La x tanδ1) within a defined range, enhancing both performance metrics.
Implementation Method 1
a loss tangent tanδ1 of the tread rubber at 30 degrees C
Implementation Method 2
small vibrations of the tires during running are transmitted to the vehicle body
Implementation Method 3
a reinforcing cord layer including at least one belt ply of steel cords rubberized with topping rubber
Data Source
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AI summary
A pneumatic tire (1) comprises a tread portion (2) comprising: a reinforcing cord layer (10) including at least one belt ply (7A) of steel cords (12) rubberized with topping rubber (13); and a tread rubber (2G) forming a part of the tread portion (2) from a ground contacting surface (2s) of the tread portion (2) to the radially outer side of the reinforcing cord layer (10). A product T1 x T2 x La x tanδ1 is 0.33 to 1.10, wherein T1 is the thickness in mm of the tread rubber (2G) measured at the tire equator (C); T2 is the average thickness in mm of the or each belt ply (7A); La is the land ratio of the ground contacting surface (2s); and tanδ1 is the loss tangent of the tread rubber (2G) at 30 degrees C.