Angled Vent Slots in Vulcanization Molds for Tire Traction

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Solution Overview

Problem

Existing vulcanization molds for pneumatic vehicle tires result in low elevations on the tread due to ventilation slots, which significantly reduce the net contact area and impair ice and snow grip properties.

Innovation Solution

The ventilation slots in the vulcanization mold are angled between 60° to 90° relative to the center line of the lamellar plates, making them shorter and narrower, thereby minimizing their impact on the tread's surface and maintaining effective mold ventilation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If vent slots are formed in the mold parts to ensure reliable mold venting, then mold ventilation is improved, but raised areas are created on the tread that reduce the net contact area and impair ice and snow grip properties

Engineering Contradiction:
Improvemold ventingVSAvoidreduced grip on snow and ice
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the orientation parameter of the vent slots from the conventional design (parallel to the extension direction of lamellar sheets) to a new orientation (at an angle of 60° to 90° relative to the center line of lamellar sheets). This parameter change reduces the length and area of raised areas on the tread while maintaining adequate vent slot functionality for mold ventilation, thereby preserving tire grip on snow and ice.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If vent slots run parallel to the extension direction of lamellar sheets (conventional design), then mold venting is achieved, but the raised areas extend over the entire length of the slits significantly reducing contact area

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

Solution Approach 1:

The patent introduces asymmetry in the vent slot orientation by angling them at 60° to 90° relative to the center line of lamellar sheets, rather than running them parallel to the extension direction. This asymmetric arrangement causes the raised areas to be shorter and positioned differently on the tread, reducing their impact on the net contact area while maintaining venting effectiveness.

Inventive Principle:
Principle #4Asymmetry

3Manufacturing precision

If the vent slots are made narrower (0.05 mm to 0.15 mm width), then burr formation is prevented and mold venting is improved, but the slots become less effective at discharging trapped air

Engineering Contradiction:
Improveburr-free tread surfaceVSAvoidair discharge efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent compensates for the reduced cross-sectional area of narrow vent slots by changing their orientation in a different dimension (angular orientation of 60° to 90° relative to lamellar sheet center lines). This dimensional change optimizes the effective length and positioning of the slots, allowing narrow slots to maintain adequate air discharge efficiency while preventing burr formation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP3321078B1Vulcanisation mould and pneumatic tyre for a vehicle
Publication Date: 2021.01.27 CONTINENTAL REIFEN DEUTSCHLAND GMBH
  • EP3321078B1 patent drawingFigure 1~1b
  • EP3321078B1 patent drawingFigure 2a~3b

AI summary

The invention relates to a vulcanization mold for a vehicle pneumatic tire, which has a tread with profile positives with incisions (4, 4', 4") running parallel to each other or substantially parallel to each other, with mold parts (1) forming the tread, in which lamellar plates (3, 3', 3") forming the incisions (4, 4', 4") are anchored and which are provided with profile webs (2) forming grooves, wherein straight vent slots (5) are formed in the mold parts (1) between adjacent lamellar plates (3, 3', 3") and/or between lamellar plates (3, 3', 3") and profile webs (2) in a top view, which extend from the inner side (1a) of the mold parts (1) forming the tread into the mold parts (1).The vent slots (5) extend, viewed from above on the inside (1a) of the molded parts (1) and each to a center line (L1) in the extension direction of the lamellar sheets (3, 3', 3 "), at an angle (α) of at least 60° and have a width (b1) of 0.05 mm to 0.15 mm.