Tire Cure Mold Vent Plug With Dual Annular Inlets
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Solution Overview
Problem
Conventional tire cure molds with vent holes face issues of air entrapment leading to 'bear' formation and rubber protrusions called 'spews' due to inadequate exhaust performance, as rubber flows into the holes during the curing process.
Innovation Solution
A vent plug with a cylindrical housing and a double-layered stem structure, featuring annular outer and inner inlet portions within the vent path, biased by coil-shaped springs to enhance exhaust performance by increasing the opening area of the vent path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If vent holes are provided in the molding face to exhaust air during cure, then air entrapment and bear formation are prevented, but rubber flows into the vent holes forming spews
Solution Approach 1:
A vent plug is introduced as an intermediary component in the vent hole. The vent plug includes a stem that acts as a valve element and a housing with a vent path. During cure, the vent path remains closed to prevent rubber from entering, while allowing air to be exhausted through controlled openings in the housing, thus mediating between the need to exhaust air and prevent spew formation
Solution Approach 2:
The vent plug employs a dynamic valve mechanism where the stem can move between open and closed positions. The valve path in the stem is selectively opened or closed during the cure process, allowing dynamic control of the vent hole function - closed to prevent spew formation, open to allow air exhaust when needed
2Object-generated harmful factors
If vent plugs with single annular inlet portions are used to prevent spews, then spew formation is reduced, but exhausting performance is insufficient leading to air entrapment
Solution Approach 1:
The single annular inlet portion is segmented into multiple inlet portions - specifically an outer annular inlet portion and an inner annular inlet portion. This segmentation allows the vent path to provide sufficient opening area for effective air exhaust while maintaining the closed configuration needed to prevent rubber from entering and forming spews
Solution Approach 2:
The vent path structure transitions from a single-plane annular inlet to a multi-dimensional configuration with both outer and inner annular inlet portions at different radial positions. This dimensional expansion increases the total opening area available for air exhaust while maintaining effective spew prevention
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 enhanced exhaust performance prevents air entrapment and rubber protrusions, efficiently removing air from the tire surface during the curing process, thereby improving tire manufacturing outcomes.
Implementation Method 1
a coil-shaped spring that biases the stem toward a cavity so as to open the vent path
Data Source
AI summary
A vent plug is mounted in a vent hole open in a molding face of a tire cure mold. The vent plug has a cylindrical housing having a vent path in itself, a stem that is inserted into the housing and serves as a valve element for opening and closing the vent path, and a coil-shaped spring that biases the stem toward a cavity so as to open the vent path. The vent path includes an outer inlet portion open in an annular shape between a valve seat provided to the housing and a head portion of the stem that comes in contact with the valve seat, and an inner inlet portion open in an annular shape on an inner side of the outer inlet portion.