Tire Tread Mold Side Wall Cavities for Wear-Resistant Closure Devices

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Solution Overview

Problem

Existing mold technologies face difficulties in precisely manufacturing slots on the side faces of a mold bead for molding closure devices in tire grooves, limiting the design possibilities and flexibility of closure devices over time due to wear, and causing issues with water evacuation and stress concentrations.

Innovation Solution

A mold design featuring cavities on the side faces of the bead that do not open onto the upper face, allowing for the molding of multiple closure devices spaced and overlapping along the cord, with added elements to separate and delimit these cavities, ensuring proper contact and reducing stress concentrations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If closure devices are fixed at the bottom of the groove, then the initial flexibility is good, but the flexibility decreases over time due to wear

Engineering Contradiction:
Improveflexibility of closure deviceVSAvoidservice life of closure device
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

Instead of fixing the closure device at the bottom of the groove (conventional approach), the invention inverts the mounting location to the side walls of the groove. This inversion allows the closure device to maintain its flexibility longer because the wear occurs on the tread surface rather than at the fixation point, solving the contradiction between initial flexibility and long-term durability.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention applies different mounting locations for different parts of the closure device system. By fixing the closure devices on the side walls rather than at the bottom, each location serves a specific function: the side wall fixation maintains flexibility while the closure devices still effectively block the groove opening. This local differentiation resolves the contradiction between flexibility and service life.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If slots are made on the side faces of the mold bead, then closure devices can be molded, but manufacturing precision and ease of manufacture deteriorate

Engineering Contradiction:
Improvedesign possibilities of closure devicesVSAvoidprecision of slots
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The invention moves the cavity openings from the conventional horizontal plane (side faces of the bead) to a vertical arrangement along the length of the bead. By opening the cavities on the upper face rather than on side faces, the mold utilizes the length dimension of the bead to position multiple cavities, avoiding the need for difficult precision slots on vertical surfaces while maintaining the ability to mold multiple closure devices.

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

Solution Approach 2:

Instead of opening the cavities on the side faces of the bead (conventional approach), the invention inverts the opening direction to the upper face of the bead. This inversion eliminates the need for complex precision slots on the side faces, as the cavities can be directly formed and opened from the top surface, significantly improving manufacturability while maintaining design versatility.

Inventive Principle:
Principle #13The other way round (Inversion)

3Productivity

If closure devices are spaced far apart, then water evacuation is improved, but flexibility and stress distribution worsen

Engineering Contradiction:
Improvewater evacuation efficiencyVSAvoidflexibility of closure device
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The invention arranges the cavities along the length of the bead in the longitudinal dimension rather than spacing them widely apart in the transverse direction. By opening multiple cavities on the upper face at different longitudinal positions, the design achieves effective water evacuation pathways while maintaining closer spacing that preserves flexibility and distributes stresses more evenly across the groove structure.

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

Data Source

PatentEP2814663B1Mold for vulcanizing a tire tread, comprising at least one added element in an elongated protrusion
Publication Date: 2016.04.20 MICHELIN & CO (CIE GEN DES ESTAB MICHELIN)
  • EP2814663B1 patent drawingFigure 1~2
  • EP2814663B1 patent drawingFigure 3~4
  • EP2814663B1 patent drawingFigure 5~6

AI summary

The invention relates to a mold for vulcanizing a tire tread. Said mold comprises a molding surface capable of molding the rolling surface of the tire tread, and at least one cord (43) having a length L and a width W for molding a groove in the tread. The cord (43) comprises two side surfaces (46A, 46B) extending along the length of the cord and protruding from the molding surface, and an upper surface connecting said side surfaces. The mold comprises, in the cord, at least two recesses (47A, 47B) leading to the two side surfaces of the cord, respectively, but not leading the upper surface of the cord. Said recesses overlap in the width of the cord. The mold further includes a first element (45) that is added into the cord in advance, wherein said first element (45) separates the two cavities along the length of the cord.