Tire Curing Mold Vent Plug Design for Rubber Biting Prevention
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Solution Overview
Problem
The existing tire curing molds with spring vents suffer from rubber biting, where uncured rubber flows into the vent plug's housing, causing operational defects and an uneven tire surface, and the protruding design can give the tire an unusual appearance.
Innovation Solution
A tire curing mold with a vent plug featuring a tubular housing, a stem, and an urging member, where the top surfaces of the housing and stem are flat and arranged closer to the cavity side than the molding surface, reducing rubber inflow and preventing rubber biting, and the edge connection between the exhaust hole and molding surface is curved or inclined to minimize stress concentrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a spring vent plug is used to exhaust air during tire curing, then air discharge efficiency is improved, but uncured rubber flows into the housing and causes rubber biting that entwines the spring
Solution Approach 1:
The patent positions the top surface of the head portion closer to the cavity side than the molding surface, creating a preliminary barrier that prevents uncured rubber from flowing into the housing before the rubber can reach the spring. This preliminary positioning action eliminates the need for post-cure cleaning and maintains vent plug reliability.
Solution Approach 2:
The head portion of the stem acts as an intermediary element between the cavity and the spring. By positioning its top surface closer to the cavity side, it serves as a mediator that intercepts uncured rubber flow and prevents direct contact between the rubber and the spring, thereby protecting the spring from entwinement.
2Object-affected harmful factors
If the top surface of the stem is arranged to sink from the molding surface to prevent rubber biting, then rubber inflow is reduced, but a distinctive projection is formed on the tire outer surface giving an unusual appearance
Solution Approach 1:
The patent positions the top surface of the head portion closer to the cavity side than the molding surface, creating a preliminary barrier that prevents uncured rubber from flowing into the housing before the rubber can reach the spring. This preliminary positioning action eliminates the need for post-cure cleaning and maintains vent plug reliability.
Solution Approach 2:
The head portion of the stem acts as an intermediary element between the cavity and the spring. By positioning its top surface closer to the cavity side, it serves as a mediator that intercepts uncured rubber flow and prevents direct contact between the rubber and the spring, thereby protecting the spring from entwinement.
3Productivity
If exhaust holes are provided on the molding surface to discharge excess air, then air discharge is improved, but uncured rubber can flow into the exhaust holes and cause defects
Solution Approach 1:
The patent positions the top surface of the head portion closer to the cavity side than the molding surface, creating a preliminary barrier that prevents uncured rubber from flowing into the housing before the rubber can reach the spring. This preliminary positioning action eliminates the need for post-cure cleaning and maintains vent plug reliability.
Solution Approach 2:
The head portion of the stem acts as an intermediary element between the cavity and the spring. By positioning its top surface closer to the cavity side, it serves as a mediator that intercepts uncured rubber flow and prevents direct contact between the rubber and the spring, thereby protecting the spring from entwinement.
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 suppresses rubber biting, maintains the tire's outer appearance quality by reducing projections and preventing cracks, ensuring smooth surfaces and improved air discharge efficiency.
Implementation Method 1
an urging member (a spring) which urges the stem toward the cavity so as to open the exhaust passage
Implementation Method 2
a lot of exhaust holes are provided on a molding surface which comes into contact with an outer surface of the tire, thereby discharging excess air between the tire and the molding surface to an external portion
Data Source
AI summary
A tire curing mold has a vent plug installed to an exhaust hole open to a molding surface. The vent plug has a tubular housing having an exhaust passage, a stem inserted to the housing, and an urging member which urges the steal toward the cavity so as to open the exhaust passage. The stem has a head portion which closes the exhaust passage by contacting with an inner surface of an opening portion in the housing. A top surface of the opening portion in the housing and a top surface of the head portion are formed by a flat surface. The top surface of the opening portion in the housing and the top surface of the head portion in a state in which the exhaust passage is closed are both arranged closer to an opposite side to the cavity than the molding surface.