Pneumatic Tire Carcass Polyester Cord Elongation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Pneumatic tires with carcass layers made of rayon fiber cords face a trade-off between maintaining steering stability on dry roads and improving shock burst resistance on wet roads, as reducing tread thickness and groove depth can compromise steering stability on wet surfaces.
Innovation Solution
A pneumatic tire design incorporating a carcass layer with polyester fiber cords having an elongation at break of 20-30%, specific groove area ratios, and increased rubber thickness in the center land portion, along with a hybrid belt cover layer, to enhance shock burst resistance and steering stability on both dry and wet surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rayon fiber cords are used in the carcass layer to ensure steering stability on dry road surfaces, then steering stability on dry roads is improved, but shock burst resistance decreases when tread thickness is reduced
Solution Approach 1:
The patent changes the material parameter from rayon fiber to polyester fiber, and specifically controls the elongation at break parameter within 20-30%. This parameter change allows the carcass cord to provide both the rigidity needed for steering stability and the elasticity needed for shock absorption, resolving the contradiction between steering stability and shock burst resistance
Solution Approach 2:
The patent uses polyester fiber cords as a composite material in the carcass layer that combines the properties of high rigidity (for steering stability) and high elongation (for shock burst resistance). This composite material approach allows simultaneous achievement of both performance requirements that were previously contradictory
2Reliability
If polyester fiber cords are used to improve shock burst resistance, then shock burst resistance is improved, but steering stability on wet road surfaces deteriorates when tread thickness is reduced
Solution Approach 1:
The patent optimizes the elongation at break parameter of polyester fiber cords to be within 20-30%, which provides the right balance between elasticity for shock absorption and rigidity for steering stability. This precise parameter control resolves the contradiction by ensuring the material has sufficient stiffness to maintain steering stability while being elastic enough for shock burst resistance
Solution Approach 2:
The patent applies different groove area ratios to different regions of the tread: 20-40% in the ground contact region and a specific ratio relationship in the center region. This local differentiation allows the tire to have adequate drainage capability for wet road steering stability while maintaining overall structural integrity for shock burst resistance
3Weight of moving object
If tread thickness is reduced for weight reduction and rolling resistance decrease, then weight and rolling resistance are reduced, but shock burst resistance decreases
Solution Approach 1:
The patent changes the material properties of the carcass cord by using polyester fiber with controlled elongation (20-30%), which provides superior elastic recovery and shock absorption capabilities. This material parameter change compensates for the reduced tread thickness, maintaining shock burst resistance while achieving weight reduction
Solution Approach 2:
The patent employs polyester fiber cords as a high-performance composite material in the carcass layer that provides enhanced tensile strength and elasticity. This composite material approach allows the tire structure to compensate for reduced tread thickness, maintaining shock burst resistance while reducing overall weight
4Weight of moving object
If tread thickness is reduced for weight reduction, then weight is reduced, but steering stability on wet road surfaces deteriorates
Solution Approach 1:
The patent implements local quality differentiation by setting specific groove area ratios for different tread regions: 20-40% in the ground contact region and a controlled ratio relationship in the center region. This local optimization ensures adequate drainage capability in critical areas for wet road steering stability while allowing overall tread thickness reduction for weight savings
Solution Approach 2:
The patent optimizes the groove geometry parameters, including groove area ratios and depth (5-8mm in center region), to enhance drainage performance. These parameter changes compensate for reduced tread thickness, maintaining water evacuation capability and steering stability on wet roads while achieving weight reduction
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 achieves improved shock burst resistance and steering stability on wet roads while maintaining good stability on dry roads, with reduced weight and rolling resistance, through balanced performance enhancements.
Implementation Method 1
an elongation at break EB of the carcass cord being from 20% to 30%... the carcass cord easily follows local deformation, the deformation during a plunger energy test (when the carcass cord is pressed by a plunger) can be sufficiently tolerated
Data Source
AI summary
In a pneumatic tire including a tread portion, a sidewall portion, a bead portion, a carcass layer mounted between a pair of bead portions, a plurality of main grooves extending in the tire circumferential direction and formed in the tread portion, and a plurality of land portions defined by the main grooves, the carcass layer includes a carcass cord formed of a polyester fiber cord, an elongation at break of the carcass cord is from 20% to 30%, and a groove area ratio SgA in a ground contact region of the tread portion is from 20% to 40%, a groove area ratio SgB in a center region of the tread portion satisfies a relationship 1.1≤SgB/SgA≤1.5, and a depth of the main groove included in the center region is from 5 mm to 8 mm.