Run-Flat Tire Crown Corrugation for Comfort and Low Rolling Resistance
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Solution Overview
Problem
Existing run-flat tires compromise between comfort, rolling resistance, and handling due to the presence of rigid sidewall inserts, which affect performance when inflated and under zero pressure.
Innovation Solution
Incorporating a corrugated crown layer with a relatively small axial distance between the sidewall insert and the innermost crown layer, combined with a rigid elastomeric composition, to enhance lateral and vertical stiffness while maintaining flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid sidewall insert is present in the crown block, then the tyre can run flat and handling is improved, but comfort and rolling resistance are worsened
Solution Approach 1:
The sidewall insert is segmented into two distinct parts: a first sidewall insert arranged in the sidewall for run-flat support, and a second sidewall insert arranged in the crown block for handling enhancement. This segmentation allows each part to perform its specific function independently, preventing the entire sidewall insert from deforming the tyre shape when inflated, thus improving comfort while maintaining run-flat capability and handling.
2Ease of operation
If a rigid sidewall insert is present in the crown block, then handling is improved, but rolling resistance increases
Solution Approach 1:
The sidewall insert is divided into two functional segments: one in the sidewall for structural support and one in the crown block for handling. This segmentation allows the handling-related functions to be localized to the crown block area, reducing the overall impact on rolling resistance while maintaining improved handling characteristics.
Solution Approach 2:
The second sidewall insert is specifically positioned in the crown block region where handling performance is most critical. This local placement provides enhanced handling qualities precisely where needed, while minimizing the insert's influence on the overall rolling resistance of the tyre.
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
This configuration improves comfort and reduces rolling resistance without worsening handling, achieving a balanced performance in run-flat tires.
Implementation Method 1
the crown reinforcement comprises at least one crown layer, referred to as corrugated, comprising reinforcing elements embedded in a polymeric matrix
Implementation Method 2
the sidewall insert comprises at least one elastomeric composition referred to as rigid, the or each rigid elastomeric composition of the sidewall insert having a modulus at 10% extension greater than or equal to 4 MPa
Data Source
AI summary
A tire (10) comprises a crown block (12), two beads (32), and two sidewalls (30) connecting each bead (32) to the crown block (12). The crown block (12) comprises a crown reinforcement (16) comprising a corrugated crown layer (24, 26, 28) comprising corrugations. The tire (10) comprises a sidewall insert (90) comprising a rigid elastomeric composition (92, 93, 94) of which the radially exterior end (96) is arranged: radially to the outside of the equator (E) of the tyre, and axially to the inside of the axial end (241, 242) of the radially innermost crown layer (24) of the crown reinforcement (16) and at an axial distance ENG≤20 mm from the axial end (242).