Single-Ply Tire Carcass Structure for Reduced Sidewall Deformation
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Solution Overview
Problem
Existing tires for SUVs and light trucks with high sidewall heights and load indices suffer from unsightly sidewall deformations due to the use of multiple carcass plies, leading to increased rolling resistance, mass, and customer returns.
Innovation Solution
A tire design featuring a single carcass ply with a hybrid reinforcer element composed of aromatic polyamide and polyester strands, reducing the number of plies and enhancing the modulus of the reinforcer elements to minimize sidewall deformations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If two carcass plies are used to carry heavy loads, then the load-bearing capacity is improved, but the rolling resistance and mass increase
Solution Approach 1:
The reinforcer element uses a composite structure combining aromatic polyamide (high strength, low elongation) and polyester (lower strength, higher elongation) strands. This composite material approach allows a single ply to achieve the load-bearing capacity previously requiring two plies, while reducing hysteresis and rolling resistance due to the aromatic polyamide's superior elastic recovery properties.
Solution Approach 2:
The invention changes the material parameters of the reinforcer element by incorporating aromatic polyamide, which has significantly different mechanical properties (higher modulus, lower elongation at break) compared to conventional polyester alone. This parameter change enables a single ply to suffice for heavy-load applications, reducing both mass and rolling resistance while maintaining strength.
2Strength
If two carcass plies are used to carry heavy loads, then the load-bearing capacity is improved, but the mass increases
Solution Approach 1:
The hybrid reinforcer element combining aromatic polyamide and polyester strands creates a composite material with optimized strength-to-weight ratio. The aromatic polyamide provides high tensile strength with low density, enabling a single lighter ply to replace two heavier conventional plies while maintaining or improving load-bearing capacity.
Solution Approach 2:
By changing the material composition to include aromatic polyamide, the reinforcer element achieves higher specific strength (strength per unit mass). This parameter change allows reduction from two plies to one ply for the same load index, directly reducing the tyre's overall mass.
3Ease of manufacture
If overlaying zones with dual thickness are created during manufacturing, then the carcass plies are joined, but unsightly sidewall deformations occur
Solution Approach 1:
The invention changes the mechanical parameters of the reinforcer element by using aromatic polyamide, which has lower elongation and higher modulus compared to conventional materials. This parameter change reduces the extension difference (Δε) between overlaying and adjacent zones during inflation, minimizing sidewall hollows and deformations even when dual-thickness overlaying zones are present from manufacturing.
Solution Approach 2:
The hybrid composite reinforcer element combines materials with complementary properties: aromatic polyamide provides dimensional stability and low elongation to prevent deformation, while polyester contributes to flexibility and comfort. This composite structure mitigates the visual impact of overlaying zone deformations.
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 reduced mass, rolling resistance, and eliminates unsightly sidewall deformations after a running-in period, improving customer satisfaction and vehicle comfort.
Implementation Method 1
two multifilament strands made of polyester assembled together and helically wound around one another
Implementation Method 2
each reinforcer element of each overlaying zone Z1 absorbs a tension T generating an extension ε1 of each reinforcer element
Data Source
AI summary
A tire (10) comprises a crown (12) comprising a tread (20), a crown reinforcement (14), two sidewalls (22), two beads (24), with each sidewall (22) connecting each bead (24) to the crown (12), the crown reinforcement (14) extending into the crown (12). The tire (10) comprises a radial carcass reinforcement (32) anchored in each of the beads (24) and extending into the sidewalls (22), and the crown reinforcement (14) is radially inserted between the carcass reinforcement (32) and the tread (20). The tire (10) has a sidewall height that is greater than or equal to 110 mm and a load index that is greater than or equal to 94. The carcass reinforcement (32) comprises a single carcass ply (34) comprising at least one reinforcer element comprising an assembly formed by: a multifilament strand made of aromatic polyamide or aromatic co-polyamide; and a multifilament strand made of polyester.