Narrow Pneumatic Tire Design for Fuel Economy and Stability
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Solution Overview
Problem
Conventional pneumatic tires that reduce rolling resistance to improve fuel economy often compromise steering stability due to narrow ground contact width, and increasing tread width to maintain stability leads to increased tire weight, making it difficult to achieve both fuel economy and steering stability simultaneously.
Innovation Solution
A pneumatic tire design with a narrow width and large diameter, featuring a specific tread profile and reinforcing layers, which reduces the forward projection area while maintaining sufficient ground contact width and cornering force, achieved by partitioning the tire cross-section into regions with optimized cross-sectional areas and lengths, and incorporating inclined reinforcing layers and an air penetration preventing layer to minimize weight and rolling resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the total width and forward projection area of the pneumatic tire are decreased to reduce air resistance, then fuel economy is improved, but the ground contact width becomes narrow and steering stability is reduced
Solution Approach 1:
The patent applies parameter changes by optimizing the ratio of total width to outer diameter (SW/OD ≤ 0.3) and the ratio of developed tread width to total width (TDW/SW ≥ 0.7). This allows the tire to achieve a narrow overall width for reduced air resistance while maintaining sufficient ground contact width through increased outer diameter, thereby improving fuel economy without sacrificing steering stability
Solution Approach 2:
The patent transitions from optimizing only the width dimension to considering the dimensional relationship between width and diameter. By decreasing the width while increasing the outer diameter, the patent creates a narrow-wide tire configuration that reduces forward projection area and air resistance while maintaining adequate ground contact width for steering stability
2Stability of the object's composition
If the developed tread width is increased to ensure ground contact width and maintain cornering force, then steering stability is improved, but the tire weight increases and fuel economy performance deteriorates
Solution Approach 1:
The patent applies parameter changes by optimizing the ratio of developed tread width to total width (TDW/SW ≥ 0.7) rather than simply increasing absolute dimensions. This allows the tire to achieve sufficient ground contact width for steering stability while controlling the overall width to minimize weight and improve fuel economy
Solution Approach 2:
The patent applies local quality by concentrating the tread width optimization in the contact patch region. The developed tread width is maximized relative to the total width to ensure adequate ground contact for cornering force, while the sidewall and other regions are optimized to minimize overall weight
3Weight of moving object
If the volume of the tire regions is reduced to minimize tire weight, then fuel economy is improved, but the ground contact width may be insufficient for maintaining cornering force
Solution Approach 1:
The patent applies parameter changes by optimizing the ratio of developed tread width to total width (TDW/SW ≥ 0.7) and the ratio of total width to outer diameter (SW/OD ≤ 0.3). This ensures that the tire volume is minimized for reduced weight while the tread region maintains sufficient dimensions for adequate ground contact width and cornering force
Solution Approach 2:
The patent segments the tire into functional regions with different optimization priorities. The tread region is optimized for ground contact width and cornering force, while the overall tire dimensions are optimized for weight reduction. The boundary between these regions is defined by the optimized width-to-diameter ratio
Data Source
AI summary
A pneumatic tire has a ratio SW/OD between the total tire width SW and the tire external diameter OD satisfying SW/OD≤0.3. A first region A is defined between a pair of first boundary lines, second regions B are defined between a first boundary line and a second boundary line, and third regions C are defined on the bead toe side of the second boundary lines. Defining SA, SB, and SC as the cross-sectional area (mm2) of the first region A to the third region C, and defining the peripheral length (mm) of the first region A to third region C along the tire inner surface as a, b, and c, SA/a and SB/b satisfy 7.5≤SA/a≤11.5 and 2.0≤SB/b≤6.0, and the ratio TDW/SW between the developed tread width TDW and the total tire width SW satisfies 0.7≤TDW/SW≤0.95.