Run-Flat Tire Inner Layer Segmentation for Airtightness
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Solution Overview
Problem
Prior art runflat tires face issues with the inner liner detaching during runflat operation, leading to loss of airtightness, which increases manufacturing costs and weight.
Innovation Solution
The inner layer does not cover the upper ends of the reinforcement profiles axially on the inside, eliminating free edges that could detach, and is strategically positioned between the upper ends with additional inner layer strips in the bead area to ensure airtightness and secure the edges, using a non-butyl rubber mixture where necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the inner layer is omitted within the cross-sectional height of the reinforcement profile, then material savings reduce costs and weight, but the inner layer edges may detach during run-flat operation causing air leakage
Solution Approach 1:
The inner layer is segmented into two separate parts: one in the bead area and another between the upper ends of the reinforcement profiles, omitting it within the cross-sectional height of the reinforcement profile. This segmentation reduces material usage and weight while maintaining airtightness through strategic placement of inner layer segments that prevent detachment.
Solution Approach 2:
The inner layer is selectively positioned in specific local areas where it provides maximum benefit: in the bead area to ensure airtightness and between the upper ends of reinforcement profiles to prevent edge detachment. The inner layer is omitted in the cross-sectional height of the reinforcement profile where it would not contribute to airtightness but would create detachment risks.
2Ease of manufacture
If the inner layer is omitted within the cross-sectional height of the reinforcement profile, then manufacturing costs are reduced, but the inner layer edges are exposed and vulnerable to detachment
Solution Approach 1:
The inner layer is divided into discrete segments placed at critical locations rather than forming a continuous layer. This segmentation reduces material costs and manufacturing complexity while ensuring airtightness through strategic placement in the bead area and between reinforcement profile upper ends.
Solution Approach 2:
The inner layer is extracted from the cross-sectional height of the reinforcement profile where it would create detachment problems, while being retained in the bead area and between upper ends where it provides essential airtightness and prevents edge exposure. This selective extraction reduces material usage and manufacturing cost.
Data Source
Figure 1
AI summary
A pneumatic vehicle tire with run-flat properties, having a tread (1), having a multi-ply belt assembly (2), having an inner ply (4) which is of air-tight form, having a carcass (3) which, in the bead region (5), is led from axially inside axially outward as a carcass turn-up (3a) around tension-resistant cores (6), and having side walls (8) within which there is arranged at least one reinforcement profile (9) which is of sickle-shaped cross section and which is of closed ring-shaped form around the circumference of the side wall, wherein the inner ply (4) does not run continuously through the tire cross section from bead region (5) to bead region (5), it rather being the case that, within the cross-sectional height (10) of the reinforcement profile (9), the inner ply is omitted; the inner ply (4a) is, in a region situated opposite the tread (1), arranged between the two upper ends (11) of the reinforcement profiles (9), and the inner ply (4a) does not cover said two ends (11) of the reinforcement profiles (9) axially at the inside.