Tire Tread Cover Layer Shaping via Mold Blade
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Solution Overview
Problem
Existing methods for manufacturing tire treads with cover layers on raised elements face challenges such as shear force-induced cracking and alignment difficulties, leading to inconsistent shape and thickness, which reduces tire performance and complicates the manufacturing process.
Innovation Solution
A method involving a mold with a blade to cut and shape the cover layer during the molding process, ensuring uniform application and integration of the cover layer into the tire tread, using cutting means that can be adjusted to fit the characteristics of the layer and materials like elastomeric materials with woven or nonwoven fibers for enhanced mechanical integrity and cohesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the insert is shaped by ribs of a vulcanizing mold to form a cover layer, then the cover layer can be formed on lateral faces, but significant shear force causes cracking within the insert and makes material movement control difficult
Solution Approach 1:
The insert is pre-shaped with a thickness greater than the final desired cover layer thickness before being placed in the mold. This preliminary action allows the rib to push the excess material forward during vulcanization without subjecting it to excessive shear forces, as the material is already positioned and oriented correctly.
Solution Approach 2:
The shaping process is divided into two distinct stages: first, the insert is pre-shaped independently with excess material; second, during vulcanization, the rib pushes the material forward to achieve the final thickness. This segmentation avoids applying complex shear forces during the entire process.
2Shape
If the insert is shaped by ribs of a vulcanizing mold, then the cover layer is formed, but the shear force makes control of material movements more difficult
Solution Approach 1:
The insert is pre-shaped with excess material and correct orientation before molding. This preliminary preparation simplifies the subsequent molding operation, as the material is already positioned to move forward in a single direction under compression, rather than requiring complex in-mold shaping.
Solution Approach 2:
Instead of trying to shape the insert to the final thickness before molding, the invention inverts the approach by providing excess material and removing it during the molding process itself, using the rib to push material forward rather than cutting or compressing it to final dimensions.
3Manufacturing precision
If inserts are aligned with ribs during manufacturing, then the cover layer can be properly positioned, but the manufacture of the tread becomes more complicated
Solution Approach 1:
The rib structure serves multiple functions: it defines the groove geometry, positions the insert during placement, and pushes the excess material forward during vulcanization. This multi-functionality eliminates the need for separate alignment mechanisms or complex positioning systems.
Solution Approach 2:
The insert design includes protrusions that automatically engage with corresponding features on the rib or mold, enabling self-alignment during placement. This self-service alignment mechanism eliminates the need for complex external alignment equipment or procedures.
Data Source
AI summary
Method of manufacturing a tire tread having a plurality of raised elements, each having a contact face intended to come into contact with a ground when the tire is rolling and lateral faces connected to this contact face. The method of manufacture comprises:preparing a green form of the tire;laying a cover layer over all or part of an external surface of the green tire;laying the green tire in a mold;with the mold comprising a blade, using this blade to mold a lateral face of a raised element;vulcanizing the green tire to obtain the tirecutting the cover layer using cutting means belonging to the mold;during the molding of the lateral face driving with the blade a cut part of the cover layer into the green tire so that the lateral face of the raised element is partially or fully covered.