Hybrid Hooping Reinforcement for Motorcycle Tire Curing Stability
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Solution Overview
Problem
The existing motorbike tyres with high equivalent initial tensile modulus in the uncured state are prone to significant variations in performance due to elongation variability during the curing process, leading to unpredictable modifications in mechanical properties and higher costs, while maintaining profile and burst pressure.
Innovation Solution
A tyre with a hoop reinforcement comprising a hybrid assembly of aromatic polyamide and aliphatic polyamide strands wound in a helix, with a twist factor ranging from 5.5 to 6.5, embedded in a polymer composition to form an uncured hooping ply with a modulus of 330 to 620 cN/tex/dm, allowing for improved endurance and reduced cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high equivalent initial tensile modulus is used in the uncured state to maintain tyre profile and burst pressure, then the tyre structure is stable, but the performance becomes unpredictable due to significant variations from curing elongation variability
Solution Approach 1:
The patent changes the physical-chemical parameters of the hoop reinforcement by using a hybrid polyamide composition (mixing aromatic and aliphatic polyamides) and optimizing the twist factor (5.5-6.5), which fundamentally alters the modulus-elongation relationship. This creates a bi-modulus curve that decouples the sensitivity to curing elongation variations, making performance predictable despite manufacturing variabilities.
Solution Approach 2:
The patent employs a composite material system combining aromatic polyamide (providing strength and modulus) with aliphatic polyamide (providing elongation and processability). This composite approach creates a synergistic effect where the two materials compensate for each other's weaknesses, resulting in a hooping ply that maintains structural integrity while being tolerant to curing variations.
2Strength
If aromatic polyamide is used to ensure sufficient hooping force and maintain tyre profile at high speeds, then the tyre performance is improved, but the manufacturing cost increases
Solution Approach 1:
The patent applies local quality by assigning different functional roles to different components of the hybrid system: aromatic polyamide provides the critical strength and hooping force where needed, while aliphatic polyamide provides elongation and cost reduction in areas where extreme strength is less critical. This localized functional distribution optimizes both performance and cost.
Solution Approach 2:
The patent partially replaces expensive aromatic polyamide with cheaper aliphatic polyamide in the hybrid composition. While aromatic polyamide provides the essential strength, the aliphatic polyamide component reduces material cost and is acceptable for applications where the combined system meets the required performance thresholds.
3Shape
If a high equivalent initial tensile modulus is used in the uncured state, then the tyre profile is maintained, but the radial expansion during manufacturing is restricted
Solution Approach 1:
The patent creates a dynamic mechanical response through the bi-modulus curve, where the hoop reinforcement exhibits different stiffness characteristics at different strain levels. During manufacturing, the lower initial modulus allows easy radial expansion and circumferential elongation. During operation, the higher modulus at elevated strains maintains the tyre profile and prevents excessive deformation.
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 hybrid hoop reinforcement provides a bi-modulus curve for better shaping and maintaining the tyre profile and burst pressure, while reducing the impact of curing variability and lowering material costs, resulting in enhanced endurance and easier radial expansion.
Implementation Method 1
the equivalent initial tensile modulus of the uncured hooping ply ranging from 330 to 620 cN/tex/dm
Implementation Method 2
each hoop reinforcing element comprising an assembly made up: of a multifilament strand of aromatic polyamide or aromatic copolyamide, and of a multifilament strand of aliphatic polyamide, the two strands being wound in a helix around one another
Data Source
AI summary
A tire (10) for two-wheeled vehicles comprises a crown (12) comprising: a tread (20), and a hoop reinforcement (17) comprising at least one hooping ply (19) comprising one or more hoop reinforcing elements (44) comprising an assembly made up of a multifilament strand of aromatic polyamide or aromatic copolyamide (47) and of a multifilament strand of aliphatic polyamide (48). The twist factor K of the hoop reinforcing element (44) ranges from 5.5 to 6.5. The tire (10) is obtained by a method comprising a step of manufacturing the hooping ply (19), in which the bonded reinforcing elements (44) are embedded in a polymer composition in order to form the uncured hooping ply, the equivalent initial tensile modulus of the uncured hooping ply ranging from 330 to 620 cN/tex/dm.