Low-Tanδ Pneumatic Tire Geometry for Stable Handling
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Solution Overview
Problem
Conventional pneumatic tires exhibit significant changes in handling characteristics between low-speed and high-speed running, and have insufficient durability.
Innovation Solution
A pneumatic tire design featuring a rubber composition with a loss tangent of 0.25 or less and a specific tread shape with circumferential grooves, along with optimized cross-sectional dimensions, to reduce rolling resistance and enhance durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the rubber composition formulation is optimized to reduce rolling resistance, then fuel efficiency is improved, but handling characteristics change significantly between low-speed and high-speed running
Solution Approach 1:
The patent applies parameter changes by precisely controlling the loss tangent of the rubber composition at 15°C to be 0.25 or less, and by optimizing the relationship between tire virtual volume V and cross-sectional width Wt (V/Wt ≤ 20000 mm²). These parameter optimizations enable the tire to maintain stable handling characteristics across different speeds while achieving low rolling resistance, resolving the contradiction between fuel efficiency and handling stability.
2Loss of energy
If the rubber composition is optimized for low rolling resistance, then fuel efficiency is improved, but durability is insufficient
Solution Approach 1:
The patent resolves this contradiction by optimizing multiple parameters simultaneously: the loss tangent at 15°C is controlled at 0.25 or less to reduce heat generation and improve durability, while the V/Wt ratio is optimized to maintain structural integrity. This multi-parameter optimization achieves both low rolling resistance and high durability without compromise.
3Ease of operation
If the tire structure is designed to suppress handling changes, then stability is improved, but heat generation increases reducing durability
Solution Approach 1:
The patent resolves this contradiction by setting the loss tangent at 15°C to 0.25 or less, which reduces heat generation during operation. Combined with the optimized V/Wt ratio, this parameter control enables the tire to maintain stable handling characteristics while generating less heat, thereby improving durability without sacrificing handling stability.
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 effectively suppresses changes in handling characteristics and improves durability by reducing heat generation and centrifugal force, while maintaining low rolling resistance.
Implementation Method 1
a rubber layer constituting the tread portion is formed by a rubber composition having a loss tangent (15℃tan δ) of 0.25 or less measured under conditions of 15℃, frequency 10 Hz, initial strain 5%, and dynamic strain rate 1%
Data Source
AI summary
Provided is a pneumatic tire having a sufficiently suppressed change in handling property and sufficiently improved durability. This pneumatic tire comprises a tread portion including a rubber layer, the rubber layer is formed of a rubber composition having 0.25 or less of a loss tangent (15°C tanδ) measured under such conditions as 15°C, frequency 10 Hz, initial strain 5%, and dynamic strain rate 1%, the tread portion includes a plurality of rib-like land portions formed by circumferential grooves continuously extending in the circumferential direction, the tread portion has a ground contact surface partitioned, at the equatorial plane, such that one ground contact area Sa and the other ground contact area Sb satisfy a relationship of Sa>Sb, and (formula 1) and (formula 2) are satisfied where Wt (mm) is the cross sectional width of the tire, Dt (mm) is the outer diameter, and V (mm3) is a virtual volume being the volume of a space occupied by the tire when the tire is mounted on a standard rim and the internal pressure is 250 kPa. 1600≤Dt2×π/4/Wt≤2827.4 V+1.5×107/Wt≤2.88×105