Tyre Tubular Structure Variable Thickness Profile

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Solution Overview

Problem

Traditional tyre manufacturing processes result in uneven thickness of tubular structures, leading to potential tearing, micropunctures, and reduced tyre performance due to significant circumferential deformation during the shaping step, especially in the carcass structure's axially internal portions.

Innovation Solution

A method is developed to determine and impose a variable thickness profile on tubular structures before the shaping step, ensuring a substantially even thickness after deformation by varying the overlapping of coils or tension along the axial extension, using mathematical models to calculate the required starting thickness based on the undeformed and deformed radii, thereby compensating for deformation and preventing thickness unevenness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional tyre manufacturing processes are used with constant thickness tubular structures, then the manufacturing process is simple, but the thickness becomes uneven after shaping deformation causing tearing and micropunctures

Engineering Contradiction:
Improvethickness uniformityVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by calculating and imposing a variable thickness profile on the tubular structure before the shaping step. The thickness is pre-adjusted in the axial direction based on predicted deformation, so that after shaping, the thickness becomes substantially uniform. This prevents tearing and micropunctures that would occur with constant thickness structures undergoing significant circumferential deformation.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If variable thickness profile is imposed before shaping, then thickness uniformity after shaping is improved, but the manufacturing process complexity increases

Engineering Contradiction:
Improvethickness uniformityVSAvoidmanufacturing ease
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by modifying the thickness parameter of the tubular structure along its axial extension. Instead of maintaining constant thickness, the thickness is varied according to a calculated profile that compensates for expected deformation during shaping. This parameter adjustment ensures uniform thickness after shaping while managing the complexity through systematic calculation methods.

Inventive Principle:
Principle #35Parameter changes

3Shape

If significant circumferential deformation occurs during shaping, then the tyre takes the desired toroidal shape, but the tubular structure experiences tearing and micropunctures

Engineering Contradiction:
Improvetoroidal conformationVSAvoidstructural integrity
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The patent applies preliminary anti-action by pre-imposing a variable thickness profile that counteracts the harmful effects of circumferential deformation during shaping. The thickness is increased in regions that will undergo greater deformation, creating a compensatory effect that maintains structural integrity and prevents tearing and micropunctures while still achieving the desired toroidal shape.

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP2212102B1Method for manufacturing tyres for vehicle wheels
Publication Date: 2013.04.17 PIRELLI TYRE SPA
  • EP2212102B1 patent drawingFigure 1
  • EP2212102B1 patent drawingFigure 2a~3b
  • EP2212102B1 patent drawingFigure 4~5

AI summary

A method of manufacturing tyres for vehicle wheels, said method comprising the following steps: a) building a carcass structure (2); b) building a belt structure (3); c) building a tread band (4); wherein at least one of the carcass structure (2), belt structure (3) and tread band (4) comprises a tubular structure (10a, 10b) of elastomeric material; d) shaping said carcass structure (2) into a toroidal conformation to associate it with at least said belt structure (3) by exerting a radial deformation force directed from the inside to the outside of said carcass structure (2); said method comprising the following step, during execution of at least one of steps a), b) and c) : e) building said tubular structure (10a, 10b) in such a manner that the profile thereof, along its circumferential extension, has such a starting thickness that the deformed tubular structure (10b) following step d) has a substantially uniform thickness.