Dual-Layer Carcass Reinforcement for Light Truck Tire Bead Stability
Solution Overview
Problem
Conventional tires for light trucks face challenges in achieving a balance between weight reduction and maintaining satisfactory endurance performance, particularly under heavy loads and severe rolling conditions, due to complex manufacturing processes and issues with carcass reinforcement layer proximity.
Innovation Solution
A tire design featuring a radial carcass reinforcement with two layers of textile elements, where the first layer is turned around the bead wire with radially outward ends and the second layer extends without reversal, incorporating specific rubber compounds and reinforcing elements with optimized stiffness and elongation properties to distribute forces effectively, reducing weight while enhancing endurance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the carcass reinforcement is made up of two layers with both layers turned around the bead wire, then the structural symmetry is improved, but the manufacturing complexity increases due to different semi-finished product dimensions and complex laying devices
Solution Approach 1:
The carcass reinforcement is divided into two distinct layers with different functions: the first layer (carcass layer) is turned around the bead wire to provide basic structural support, while the second layer (anti-rock layer) extends without reversal to prevent bead rocking. This segmentation allows each layer to be optimized independently, simplifying the manufacturing process while maintaining structural stability.
2Reliability
If the two layers of carcass reinforcement are turned around the bead wire with radially offset ends, then the disturbance zones in polymer blends are avoided, but the manufacturing process becomes more complex requiring different semi-finished products
Solution Approach 1:
The first layer is configured with radially offset ends to avoid creating disturbance zones in the polymer blends at critical locations. This local quality adjustment ensures polymer integrity in the bead area while the second layer maintains continuous coverage without reversal, simplifying its manufacturing.
3Object-generated harmful factors
If the second layer covers the reversals of the first layer in the bead areas, then the proximity of rollover ends is avoided, but the holding of the outermost carcass reinforcement layer becomes more delicate under heavy loads
Solution Approach 1:
The patent employs a composite structure where the first layer (carcass layer) and second layer (anti-rock layer) have different mechanical properties and configurations. The carcass layer provides basic strength with turned-around ends, while the anti-rock layer extends without reversal to provide enhanced load-bearing capacity and prevent bead rocking under heavy loads, creating a synergistic composite reinforcement system.
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 design results in a lighter tire with improved flexibility and endurance performance, capable of withstanding high inflation pressures and severe use conditions, with reduced shear effects and increased resistance to compression, thus outperforming conventional tires in terms of longevity and load-bearing capacity.
Implementation Method 1
a first filler element, axially inside the outer surface of a sidewall and axially outside the upturn of the first layer of carcass reinforcement, consisting of rubber compound having a secant modulus of elasticity under tension at 10% elongation Mj
Implementation Method 2
each bead comprising a second filling element, consisting of rubber compound having a secant modulus of elasticity under tension at 10% elongation Mt, extending radially towards outside the bead core
Data Source
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AI summary
The invention relates to a tyre with an inflation pressure no lower than 6 bars, made up of at least two layers (2, 6) of reinforcing elements. The first layer (2) is folded back around the bead wires and the second layer (6) extends from one bead to the other, the ends thereof being axially external to the most axially external of each of the bead wires. According to the invention, each of the carcass reinforcement layers (2, 6) has a breaking strength per unit of width of more than 2250 daN/dm, the minimum rigidity per unit of width, measured for an elongation of less than 10 %, of the second carcass reinforcement layer being strictly greater than a value equal to 20 % of the minimum rigidity per unit of width, measured for an elongation of less than 10 %, of the first carcass reinforcement layer, the reinforcing elements of the two carcass reinforcement layers having a yarn count of less than 750 tex, the elongation of the reinforcement layers of the second carcass reinforcement layer being greater than 4 % under a force of 20 daN, and the secant modulus of elasticity under tension at 10 % elongation Mt, Mj comply with the relation Mt/Mj > 1.