Vulcanization Mold Ventilation Holes for Tire Tread Integrity

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Solution Overview

Problem

Conventional vulcanization molds with large ventilation holes create small elevations on the tire tread, which reduce the net contact area and impair winter driving properties on ice and snow.

Innovation Solution

The design incorporates small, closely spaced ventilation holes with diameters of 0.05 mm to 0.15 mm on the lamellar plates, connected to larger ventilation channels, reducing tread elevations and enhancing mold ventilation without affecting the tire's contact area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If large ventilation holes with diameter of 3 mm to 5 mm are used in the vulcanization mold, then mold ventilation is ensured, but pronounced elevations are formed on the tread strip reducing net contact area

Engineering Contradiction:
Improvemold ventilationVSAvoidnet contact area of tread
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent changes the critical parameter of ventilation hole diameter from conventional 3-5 mm to a much smaller range of 0.05-0.15 mm. This parameter change allows the holes to be effectively closed by the green tire during molding, preventing elevation formation while still providing adequate ventilation pathways for air evacuation during the vulcanization process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the ventilation function by providing multiple tiny ventilation holes (at least two, preferably at least three) on each side of the lamellar plate rather than using fewer large holes. This segmentation distributes the ventilation function across multiple small openings, collectively providing sufficient air evacuation while each individual hole remains small enough to be closed by the tire material.

Inventive Principle:
Principle #1Segmentation

2Reliability

If ventilation holes are positioned close to lamellar plates, then ventilation effectiveness in sensitive area is improved, but risk of affecting tread structure increases

Engineering Contradiction:
Improveventilation effectivenessVSAvoidtread structure integrity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent specifies a precise positional parameter: the minimum distance from the center point of the ventilation hole to the lamellar plate should be 0.07 mm to 1.0 mm. This controlled positioning ensures the holes are close enough to the sensitive area to provide effective ventilation where it is most needed, while maintaining sufficient distance to avoid interfering with the structural integrity of the lamellar plate and the resulting tread incisions.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If multiple ventilation holes are provided on each side of lamellar plate, then total ventilation capacity is improved, but total area of elevations increases

Engineering Contradiction:
Improveventilation capacityVSAvoidtotal area of elevations
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent fundamentally changes the scale parameter of ventilation holes from millimeter-sized openings to sub-millimeter openings (0.05-0.15 mm diameter). This order-of-magnitude reduction in hole size means that even when multiple holes are provided on each side of the lamellar plate, the total area occupied by elevations remains negligible, while the collective ventilation capacity of multiple tiny holes remains sufficient for effective air evacuation.

Inventive Principle:
Principle #35Parameter changes

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 approach ensures effective ventilation while minimizing tread elevations, thereby maintaining or improving winter driving characteristics such as snow traction and ice braking performance.

Implementation Method 1

When molding a green tire into a vulcanization mold, air present in the vulcanization mold is trapped between the latter and the green tire and must therefore be discharged

Methodology Applied
Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentEP3272509B1Vulcanisation mould and pneumatic tyre for a vehicle
Publication Date: 2021.02.24 CONTINENTAL REIFEN DEUTSCHLAND GMBH
  • EP3272509B1 patent drawingFigure 1~6

AI summary

Vulcanization mold for a vehicle pneumatic tire with molded parts that form the profiled tread of the tire and have lamellar plates (2) forming incisions (7, 7') in the tread, wherein at least one vent hole (3) extending into the molded part and in the immediate vicinity of at least one lamellar plate (2) is formed. The vent hole (3) has a diameter (d1) of 0.05 mm to 0.15 mm.