Pneumatic Tire Vent Lines for Rubber Bareness Prevention
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Solution Overview
Problem
The challenge in manufacturing pneumatic tires is the occurrence of bareness of rubber on the outer surface due to trapped air between the tire and the vulcanizing mold, which is exacerbated by variations in tire rigidity and specifications, leading to reduced yield and inconsistent tire quality.
Innovation Solution
The implementation of circumferentially extending vent grooves and small ribs on the inner surface of the vulcanizing mold, which form vent lines and serrated areas on the tire surface, allowing air to be discharged and preventing rubber bareness by creating a serrated area between the first and second vent lines, ensuring effective air removal regardless of rigidity variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If circumferentially extending vent grooves are disposed in the inner surface of the vulcanizing mold to prevent bareness of rubber, then air can be discharged effectively, but a vent line protrudes from the outer surface of the vulcanized tire creating an undesirable rib
Solution Approach 1:
The harmful vent line protrusion is extracted and removed from the tire outer surface. Instead of having the vent groove directly form a protruding line on the tire, the invention extracts this unwanted feature by positioning the vent groove in the mold such that it does not translate to a surface protrusion on the final tire product.
Solution Approach 2:
The vent groove is positioned in a specific local region of the mold inner surface where it can effectively discharge air but will not create a visible or undesirable protrusion on the tire outer surface. This local positioning allows the venting function to be performed without the negative aesthetic consequence.
2Adaptability or versatility
If the same vulcanizing mold is used to manufacture plural kinds of tires with different specifications, then production flexibility is improved, but variations in tire rigidity cause air to remain in different positions leading to bareness of rubber
Solution Approach 1:
The vulcanizing mold is designed with a universal vent groove configuration that can effectively handle air discharge for multiple different tire types and specifications. The vent groove is positioned and dimensioned to provide multi-functional air evacuation capability across various tire designs, maintaining production flexibility while preventing bareness.
Solution Approach 2:
The vent groove parameters (position, dimensions, orientation) are optimized to accommodate variations in tire rigidity and specifications. By carefully selecting the vent groove parameters, the mold can adapt to different tire types without causing air entrapment, thus maintaining both versatility and defect-free production.
3Strength
If the bead portion has relatively higher rigidity causing latest contact in the radially inside region, then structural integrity is maintained, but air becomes entrapped in this region resulting in bareness of rubber
Solution Approach 1:
The vent groove acts as an intermediary air discharge path that facilitates the removal of entrapped air from regions where late contact occurs due to high rigidity. The vent groove provides a dedicated escape route for air that would otherwise be trapped by the rigid bead structure, allowing the bead to maintain its necessary rigidity while preventing bareness.
Data Source
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AI summary
The outer surface of the tire is provided in its region radially inside a maximum width position of the carcass with vent lines (9) extending in a tire circumferential direction, wherein the vent lines (9) include a radially inner first vent line (9A) and a radially outer second vent line (9B). The area between the first vent line (9A) and second vent line (9B) is formed as a serrated area (11) comprising a plurality of circumferentially spaced small ribs (10) extending from the first vent line (9A) to the second vent line (9B). The serrated area (11) has deepest parts and shallowest parts. The shallowest parts are located inside the ridge of each of the vent lines, and the deepest parts are located at the same level as or outside a virtual tire outer surface.