Self-Sealing Tyre Curing Pressure Gradient for Bubble Prevention
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Solution Overview
Problem
In self-sealing tires, the sealing layer integrated into the tire structure before curing may not reach the blow point, leading to gas entrapment and bubble formation due to differences in lattice density, which affects the layer's deformability and sealing effectiveness.
Innovation Solution
Applying a working pressure greater than the external environment on the radially internal surface of the tire after curing, allowing gases to escape through the radially external surface, ensuring complete evacuation and preventing bubble formation in the sealing layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sealing layer is integrated into the tire structure before curing, then the sealing material remains deformable and sticky for effective sealing, but gases become entrapped and bubbles form due to the sealing layer not reaching the blow point
Solution Approach 1:
The sealing layer is integrated into the green tire structure before curing, positioning it in the path of gas escape beforehand. This preliminary placement ensures that when gas expansion occurs during curing, the sealing layer is already in position to channel gases outward, preventing bubble formation while maintaining the material's deformability and sealing capability
Solution Approach 2:
The patent converts the potentially harmful effect of gas entrapment into a beneficial outcome by utilizing the gas pressure itself to push gases through the sealing layer during curing. The sealing layer's strategic positioning and material properties allow it to transform the harmful gas entrapment scenario into a mechanism that promotes gas evacuation, preventing bubble formation while maintaining sealing effectiveness
2Object-generated harmful factors
If the sealing layer is positioned to allow gas escape during curing, then bubble formation is prevented, but the structural integrity and stability of the tire may be compromised
Solution Approach 1:
The sealing layer is applied specifically at radially internal positions where gas generation and entrapment are most problematic during curing. This localized placement allows the sealing layer to perform its gas-management function precisely where needed, without requiring modifications to the entire tire structure, thereby maintaining overall structural integrity while preventing bubble formation in critical areas
Solution Approach 2:
The sealing layer material possesses properties that allow it to interact with gases during curing, enabling gas passage while maintaining structural coherence. The material's characteristics facilitate gas evacuation through the sealing layer without compromising the layer's structural role in the tire, thus preventing bubble formation while preserving structural stability
3Reliability
If the sealing material is kept deformable and sticky for sealing purposes, then sealing performance is improved, but the material cannot reach the blow point during curing, leading to gas entrapment
Solution Approach 1:
The sealing layer is positioned in advance within the green tire structure at locations where gas escape is critical. This preliminary positioning ensures that during curing, the sealing layer is already in place to guide gas flow, allowing the material to maintain its deformable and sticky properties for sealing while simultaneously serving as a gas evacuation pathway, thus achieving both sealing performance and curing uniformity
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 method prevents bubble formation in the sealing layer, maintaining its deformability and sealing effectiveness by ensuring gases are fully evacuated, thus enhancing the tire's structural stability and performance.
Implementation Method 1
applying a working pressure greater than the external environment on the radially internal surface of the tire after curing, allowing gases to escape through the radially external surface
Implementation Method 2
a self-sealing tyre comprises at least one layer of sealing polymeric material that can adhere to the object inserted therein and can further flow into the hole when this object is removed, thereby sealing the hole itself and preventing the escape of air from the tyre
Data Source
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AI summary
In a process for producing self-sealing tyres for vehicle wheels, a green tyre (1) is built through assembly of at least one carcass ply (3), a belt structure (6), a tread band (7) and at least one layer of sealing material (10). The green tyre (1) is submitted to a curing and molding step. When the blow point (BP) and structural stability have been reached in the carcass ply (3), the belt structure (6) and the tread band (7), the process comprises the step of applying a working pressure (P2) which is greater than the external-environment pressure (Pe) on a radially internal surface (16) of the tyre (1), which pressure is of such a nature as to counteract expansion of the gases developed during curing, internally of the sealing layer (10), until obtaining the substantial evacuation of these gases through a radially external surface (17) of the tyre (1).