Tire Forming Core with Border Recesses to Stop Rubber Flash
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Solution Overview
Problem
The existing rigid core method for tire formation results in membrane-like mold flash due to rubber biting between core segments, reducing production efficiency as the rubber adheres to mating faces and requires manual removal.
Innovation Solution
A rigid core with border recesses on mating faces, extending along the outer peripheral edge, prevents rubber from adhering as a membrane-like mold flash by providing a recess for the bitten rubber to stay and be vulcanized as a rib-like protrusion, eliminating the need for manual removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a rigid core with divided core segments is used for tire forming, then the core can be disassembled and removed after vulcanization, but rubber penetrates into the gap between mating faces and forms membrane-like mold flash that adheres to the mating faces
Solution Approach 1:
The harmful factor (rubber penetration) is extracted and isolated into a dedicated space (border recess) away from the problematic area (mating face). The border recess captures the bitten rubber before it can adhere to the mating face, effectively separating the harmful effect from its adverse location.
Solution Approach 2:
The rubber that would normally form harmful membrane-like mold flash is instead directed to form beneficial rib-like protrusions within the border recess. These rib-like structures are integral to the tire and do not require removal, converting a harmful byproduct into a beneficial feature.
2Manufacturing precision
If membrane-like mold flash adheres to mating faces, then the tire forming process is compromised, but manual removal is required which reduces production efficiency
Solution Approach 1:
The mold flash problem is extracted from the mating face area and relocated to the border recess area. By providing a dedicated containment space for the rubber, the harmful adhesion to mating faces is eliminated, maintaining manufacturing precision without sacrificing productivity.
3Stability of the object's composition
If the gap between mating faces decreases due to thermal expansion, then the core segments contact each other, but rubber that penetrated into the gap is extended as thin membrane-like mold flash
Solution Approach 1:
The border recess is prepared in advance to receive and contain the rubber before thermal expansion occurs. This preliminary preparation ensures that when the gap decreases and rubber is pushed, it has a predetermined path and containment space, preventing the formation of harmful mold flash.
Solution Approach 2:
The thermal expansion effect that closes the gap is utilized beneficially by directing the compressed rubber into the border recess where it forms useful rib-like protrusions rather than harmful membrane-like mold flash. The same physical effect that causes the problem is harnessed to create a beneficial outcome.
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
The border recesses effectively prevent membrane-like mold flash, enhancing tire manufacturing efficiency by integrating the bitten rubber as rib-like protrusions, thus improving production efficiency and maintaining tire quality.
Implementation Method 1
the temperature of the core main body (a) is changed from normal temperature (about 15 to 50 degrees C) during forming the raw tire to high temperature (100 degrees C or more) during vulcanization. Accordingly, as enlargedly shown in Figure 8 (B), the core main body (a) at the normal temperature is provided between the mating faces (cs, cs) with a gap (d) of about 0.2 mm, for example. As a result, in the thermal expansion state during vulcanization, the mating faces (cs) substantially contact with each other.
Data Source
Figure 1
Figure 2~3
Figure 4(A)~4(B)
AI summary
To prevent rubber from becoming membrane-like mold flash between mating faces and being adhered. It is a rigid core for forming a tire which comprises an annular core main body provided in an outer surface thereof with a tire molding surface for forming a raw tire. The core main body is composed of a plurality of core segments which are divided in a circumferential direction, and each of the core segments has both circumferential end surfaces as mating faces, and the mating faces adjacent to each other in the circumferential direction are butted to each other so as to form the core main body. Each of the mating faces is provided with a border recess extending along an outer peripheral edge of the mating face and formed by cutting away a corner between the tire molding surface and the mating face.