Tire Mold Bead Ring Venting via Knurled Grooves
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Solution Overview
Problem
Conventional tire molds have limited gas venting portions, leading to insufficient gas release and frequent clogging by rubber residues, increasing the occurrence of bares and requiring frequent mold cleaning.
Innovation Solution
A tire mold design featuring a knurled gas venting passage with specific gap configurations between side plates and bead rings, including a first gap from knurled grooves, a second gap with a smaller outer diameter, and a third gap with vent grooves, enhancing gas passage and reducing residue entry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional vent groove is provided on the bead ring to form a gas venting passage, then gas venting is enabled, but the number of gas venting portions is limited and gas venting cannot be performed sufficiently
Solution Approach 1:
The gas venting passage is segmented into multiple functional regions: a first gas venting passage formed by knurled grooves on the outer peripheral surface, and a second gas venting passage formed by vent grooves on the outer side surface. This segmentation creates multiple gas venting portions that work together to improve overall gas venting effectiveness.
Solution Approach 2:
The gas venting function is extended from a single plane to multiple dimensions by forming venting passages on both the outer peripheral surface (first dimension) and the outer side surface (second dimension) of the bead ring, creating a three-dimensional gas venting network.
2Reliability
If the gas venting passage entrance is clogged with rubber residues, then gas venting becomes more insufficient, but changing or cleaning the mold frequently increases production time and cost
Solution Approach 1:
Different regions of the bead ring are given different surface characteristics: the outer peripheral surface has knurled grooves with specific geometric properties (width 8-16mm, pitch 1.3-2.0mm, height 0.54-0.83mm) that prevent rubber residue adhesion, while the outer side surface has vent grooves (width 1.0-4.0mm, depth 0.5-1.5mm) optimized for gas discharge. This local differentiation ensures smooth gas flow and prevents clogging.
Solution Approach 2:
The geometric parameters of the venting passages are optimized to prevent rubber residue accumulation. The knurled grooves have specific width, pitch, and height ratios that create a smooth flow path, while the vent grooves have dimensions that allow efficient gas discharge without trapping residues, maintaining gas venting effectiveness over 1000+ tires.
3Ease of operation
If the outside diameter of the second outer peripheral surface is made smaller than the first, then a level difference is created to improve gas flow, but the structural complexity increases
Solution Approach 1:
The bead ring structure incorporates a dynamic level difference between the first and second outer peripheral surfaces, where the second surface has a smaller outside diameter. This creates a gradual slope that dynamically guides gas flow from the first gas venting passage to the second, improving gas discharge efficiency without requiring complex mechanical components.
Data Source
AI summary
A tire mold comprising a pair of side plates, a pair of bead rings abutting on the side plates, and a gas venting passage, wherein each of the bead rings has: a cavity surface; an outer side surface; and an outer peripheral surface having two regions, wherein a first and second outer peripheral surface adjoins the cavity surface. A first gap is lying between the first outer peripheral surface and the side plate by the presence of a knurled groove. A second gap is lying between the second outer peripheral surface and the side plate. A third gap is lying between the outer side surface and the side plate by the presence of a plurality of vent grooves. The first to third gaps function as the gas venting passage.