Contoured Inner Layer for Self-Sealing Tire Moisture Protection
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Solution Overview
Problem
Pneumatic vehicle tires with self-sealing properties face challenges in moisture absorption during the green tire stage due to the use of recycled rubber compounds and the absence of an airtight inner layer, leading to variations in material properties and potential damage to the tire building machine.
Innovation Solution
A contoured inner layer with varying thicknesses, where thicker areas are overlapped by the sealant layer, providing protection against moisture absorption and ensuring airtightness, while using expensive airtight materials only where necessary and employing a low-density film for cost savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If an airtight inner layer is completely removed to save material costs, then material costs are reduced, but moisture absorption during the green tire stage increases
Solution Approach 1:
The inner layer is designed with spatially varying thickness: a thin area (1-3 mm) under the sealant layer for cost savings, and thicker areas (3-6 mm) at the sidewalls and beads for moisture protection. This local differentiation resolves the contradiction by providing moisture protection only where the green tire is exposed to moisture during storage and assembly.
Solution Approach 2:
The inner layer is segmented into functionally distinct regions: a thin central area covered by the sealant layer and thicker peripheral areas at the sidewalls and beads. This segmentation allows the tire to use minimal material in the center while maintaining moisture protection at critical exposed regions.
2Loss of substance
If recycled rubber compound is used in the inner layer, then material costs are reduced, but material property variation and machine damage risk increase
Solution Approach 1:
The inner layer uses different material qualities in different locations: recycled rubber compound in the thin central area where it is covered by the sealant layer, and virgin rubber compound in the thicker peripheral areas. This local differentiation allows cost savings with recycled material while maintaining reliability with virgin material at critical locations.
3Loss of substance
If the inner layer is made uniformly thin to save material, then material costs are reduced, but airtightness under stretching and compression deteriorates
Solution Approach 1:
The inner layer has different thicknesses in different locations: thin (1-3 mm) in the central area under the sealant layer, and thicker (3-6 mm) at the sidewalls and beads. The thicker areas maintain airtightness during tire deformation while the thin area reduces material costs.
Solution Approach 2:
The inner layer is pre-formed with varying thickness during tire manufacturing, with thicker areas positioned at locations that will experience stretching and compression during use. This preliminary structural preparation ensures airtightness is maintained under deformation without requiring uniform thickness throughout.
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 design effectively reduces moisture absorption during the production process, maintains airtightness, and reduces material costs by using expensive airtight materials only where required, ensuring the tire remains airtight even under stretching and compression.
Implementation Method 1
The sealant is a self-adhesive, viscous sealant that is applied as a layer from the radially inside in the projection area of the belt assembly to the innermost tire layer in the radial direction, the largely airtight inner layer.
Implementation Method 2
Textile reinforcements absorb moisture in the green tire stage, which can remain there in the subsequent production step and have a negative effect.
Implementation Method 3
In the subsequent production step, the vulcanization process turns the previously plastic rubber mixtures that can be crosslinked with sulfur into elastic rubber and the individual components of the green tire vulcanize with one another.
Data Source
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AI summary
The invention relates to a vehicle pneumatic tire (1) with self-sealing properties, comprising a preferably profiled tread (2), a multi-layer belt structure (6), a carcass (10) which is guided around a bead core (20) and a bead core profile (21) to a carcass high edge (19) in the area of a bead (22), a sidewall (11), an inner layer (12), and a sealant layer (13), wherein the inner layer (12) is contoured and has a lesser thickness at least in a partial area of the sealant layer (13) than in the area outside the sealant layer (13).