Tubeless Tyre Inner-Liner Slit for Bubble Prevention
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Solution Overview
Problem
Tubeless tires face issues with air bubbles forming between the inner-liner and adjacent tire components during manufacturing, leading to adhesion loss and reduced longevity, and partial inner-liner coverage increases noise and inflation pressure loss.
Innovation Solution
A tubeless tire design featuring an inner-liner with a radial slit between the annular reinforcement structure and the carcass reinforcement, allowing air to escape, and a manufacturing process that creates a crescent-shaped slit in the inner-liner during tire production to prevent bubble formation and maintain inflation pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner-liner covers the bead and radially inner portion of the sidewall to prevent inflation pressure loss, then inflation pressure retention is improved, but air bubbles form during manufacturing causing adhesion loss and reduced longevity
Solution Approach 1:
The inner-liner is segmented into two functional zones: a first portion covering the bead and radially inner sidewall for inflation pressure retention, and a second portion extending radially outward for adhesion and noise reduction. This segmentation allows each zone to perform its specific function optimally without the negative effects of full coverage.
Solution Approach 2:
Different portions of the inner-liner are given different functional qualities: the first portion (radially inner) provides airtight sealing, while the second portion (radially outer) provides adhesion to the sidewall. This local differentiation resolves the contradiction by giving each region the property it needs for its specific purpose.
2Object-affected harmful factors
If the inner-liner covers the bead and radially inner portion of the sidewall to reduce noise, then acoustic comfort is improved, but air bubbles form during manufacturing causing adhesion loss
Solution Approach 1:
The inner-liner is divided into a first portion for pressure retention and a second portion for noise reduction through adhesion. The second portion specifically covers the radially outer sidewall where noise generation occurs, while the first portion manages the manufacturing bubble issue through controlled coverage of the bead area.
Solution Approach 2:
The inner-liner provides different local qualities: the second portion (radially outer) offers sound damping through adhesion to the sidewall, while the first portion (radially inner) provides airtight sealing. This local functional differentiation allows noise reduction without compromising longevity.
3Reliability
If the inner-liner is made fully impermeable to inflation gas to prevent pressure loss, then inflation pressure retention is improved, but air trapped during manufacturing accumulates forming bubbles
Solution Approach 1:
The inner-liner is segmented radially into a first portion for airtight sealing and a second portion for adhesion. This segmentation creates a controlled interface zone that allows trapped air to escape during manufacturing while maintaining inflation pressure retention in the sealed portion.
Solution Approach 2:
The interface between the first and second portions of the inner-liner acts as an intermediary zone during manufacturing, allowing trapped air to escape. Once manufacturing is complete, this interface seals to maintain inflation pressure, thus resolving the contradiction between pressure retention and bubble formation.
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
Significantly reduces bubble formation and noise, while minimizing inflation pressure loss, enhancing tire longevity and acoustic comfort.
Implementation Method 1
the air trapped during the making of the tyre may accumulate beneath the inner-liner... These holes allow the air to escape during the making of the tyre and the first stages of vulcanization
Implementation Method 2
They close by the inner-liner flowing during vulcanization, which makes it possible to have an intact inner-liner after curing
Data Source
Figure 1~2
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Figure 9~10
AI summary
Tubeless tyre, adapted to be inflated with an inflation gas, comprising: a crown (25) comprising a crown reinforcement (80, 90) surmounted by a tread (40); two sidewalls (30) extending the crown radially inwards; two beads (20) radially inside the sidewalls and each comprising a annular reinforcement structure (70); a carcass reinforcement (60) anchored in each of the beads; an inner-liner (50) impermeable to the inflation gas, covering the inner surface of the tyre; wherein, in each sidewall of the tyre, the inner-liner comprises at least one slit (200), situated radially between the annular reinforcement structure that is radially outermost, and the radius RE at which the carcass reinforcement, when the tyre is fitted to the rim and inflated to its operating pressure, has its largest axial width, the slit having a maximum radial height HR of between 0.5 and 5 mm and extending over at least half of the circumference of the tyre. Also disclosed is a process for manufacturing such a tyre.