Pneumatic Tire Carcass Curvature Optimization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional pneumatic tires for heavy-load vehicles face challenges in reducing weight and rolling resistance while maintaining controllability and stability, as additional textile carcass plies can decrease sidewall rigidity and increase lateral displacement during cornering, affecting responsiveness and cornering force.
Innovation Solution
A pneumatic tire design featuring a carcass with specific height positions and radii of curvature, along with acute inclination angles, that enhances lateral spring constant and tension forces without requiring additional members, improving controllability and stability by optimizing the carcass structure across bead cores.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a textile carcass ply is added to enhance sidewall rigidity, then controllability and stability improve, but tire weight increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the radius of curvature of the carcass ply in different radial regions. By setting specific radius ratios (R1/R2 ≥ 0.7, R3/R4 ≥ 0.7) and acute inclination angles (α1, α2 < 45°) in the lower and upper portions respectively, the carcass structure achieves enhanced lateral rigidity without adding textile plies, thus improving controllability while maintaining lightweight design.
2Loss of energy
If tire weight is reduced to decrease rolling resistance, then fuel consumption improves, but sidewall rigidity and lateral spring constant decrease
Solution Approach 1:
The patent applies local quality by creating different structural characteristics in different regions of the carcass. The lower portion (from bead to 0.6h) has a smaller radius of curvature and acute inclination angle for enhanced rigidity, while the upper portion (from 0.6h to tread) has a larger radius of curvature for flexibility. This localized optimization maintains sidewall rigidity without requiring uniform reinforcement throughout the tire, thus reducing overall weight and rolling resistance.
3Weight of moving object
If sidewall rigidity is decreased to reduce weight, then tire weight decreases, but lateral displacement increases during cornering
Solution Approach 1:
The patent applies spheroidality by utilizing controlled curvature variations in the carcass ply. The radius of curvature in the lower portion (R1, R3) is made smaller than in the upper portion (R2, R4), creating a bulbous shape in the sidewall region. This curved geometry naturally resists lateral deformation during cornering, reducing lateral displacement while maintaining lightweight construction without additional reinforcing plies.
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 optimized carcass structure reduces lateral displacement and enhances cornering force, improving vehicle responsiveness and stability without additional components, while also potentially reducing weight and rolling resistance.
Implementation Method 1
a carcass including at least one layer of carcass ply extending in a toroidal shape across the pair of bead cores... enhances lateral spring constant and tension forces
Data Source
Figure 1
Figure 2
AI summary
A tire, wherein, in a cross section in the tire width direction thereof in a state where the tire has substantially not been inflated with no load applied thereon, provided that the maximum height in the tire radial direction of the carcass is h, a radius of curvature of the carcass within a height range 0.91h-h measured from the radially innermost position of the carcass is R7, an acute inclination angle specifically defined in the height range 0.91h-h is θ7, the intermediate value of a radius of curvature in the height range 0.82h-0.91h is R6, a radius of curvature in the height range 0.63h-0.82h is R5, and an acute inclination angle specifically defined in the height range 0.63h-0.82h is θ5, R7 ≥ 0.26h, θ7 ≥ 14°, R6 < R7, R5 > R6, and θ5 ≤ 23°.