Undulating Tire Crown and Bead Structure for Grip-Rolling Balance
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Solution Overview
Problem
Conventional tyres with undulating crown layers face performance trade-offs between behaviour and rolling resistance due to suboptimal stiffness of beads and sidewalls, which compromise the maximum improvement in grip and behaviour.
Innovation Solution
A tyre design with a crown reinforcement featuring undulating layers, reinforced beads and sidewalls, including a radial reinforcing element and specific rubber compounds, to enhance bending stiffness and distribute shear stress effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional tyres with undulating crown layers are used, then grip and behaviour are improved, but rolling resistance increases due to suboptimal stiffness of beads and sidewalls
Solution Approach 1:
The patent modifies the physical parameters of the bead and sidewall structures by introducing radial reinforcing elements and adjusting layer configurations. This changes the stiffness characteristics of these components to optimize the balance between grip/behaviour and rolling resistance, resolving the technical contradiction through parameter optimization rather than fundamental design changes
Solution Approach 2:
The patent employs composite structures in the bead and sidewall regions by combining radial reinforcing elements with traditional carcass layers and adding specific rubber compounds. This composite approach creates a synergistic effect where the reinforced bead and sidewall provide enhanced stiffness to reduce energy loss while maintaining the undulating crown's grip-enhancing properties
2Strength
If radial reinforcing elements are added to beads, then bending stiffness is enhanced, but device complexity increases
Solution Approach 1:
The patent divides the bead structure into distinct functional segments: the existing bead wire, the newly added radial reinforcing element, and the specific rubber compound layer. This segmentation allows each component to perform its specific function independently while working together as a unified system, managing complexity through functional decomposition
Solution Approach 2:
The patent introduces a new radial dimension to the bead structure by adding radial reinforcing elements that extend from the bead wire outward. This dimensional addition enhances bending stiffness by creating a more distributed reinforcement pattern, transforming the bead from a simple circular structure to a multi-dimensional reinforced structure
Data Source
AI summary
A tire comprises, in the central part of its crown, at least one undulation (51) of the radially outermost crown layer, having a radial amplitude A at least equal to 1 mm. At least one bead comprises, aside from the radial carcass layer and the bead wire, a radial reinforcing element that is such that the axial distance between the radial reinforcing element and the axially innermost carcass layer is at least equal to 1 mm and at most equal to 12 mm at the point of the radial reinforcing element that is situated 30 mm from the radially innermost point of the bead wire, for a better trade-off between the stiffness of the undulating crown and of the bead.