Sector Mold Pattern Block Attachment via Embedding Groove

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Solution Overview

Problem

Conventional tire-vulcanizing mold manufacturing faces challenges in achieving high positional accuracy and strength for pattern blocks due to distortion, warpage, and complex attachment processes, particularly with narrow-groove forming bones, which require extensive welding and manual adjustments.

Innovation Solution

A sector mold design featuring an embedding groove and positioning pins on the sector, with a pattern block having corresponding convex portions and pins, allows for precise attachment and enhanced strength by fitting these elements together, minimizing welding and eliminating the need for lapping operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the pattern block is fixed to the jig through welding along the entire periphery, then fixation strength is ensured, but a considerable number of detachment processes become necessary and distortion occurs due to welding heat

Engineering Contradiction:
Improvefixation strengthVSAvoiddetachment processes
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The pattern block is divided into multiple segments (first pattern block and second pattern block) that can be independently attached and detached. This segmentation allows for simplified detachment processes while maintaining adequate fixation strength through localized welding at attachment portions rather than entire periphery fixation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Welding is applied only at specific attachment portions of the pattern block rather than along the entire periphery. This localized welding approach ensures sufficient fixation strength at critical areas while minimizing overall heat input and resulting distortion

Inventive Principle:
Principle #3Local quality

2Strength

If the pattern block is fixed through welding along the entire periphery, then fixation strength is ensured, but distortion and warpage occur due to welding heat

Engineering Contradiction:
Improvefixation strengthVSAvoidprocessing accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The pattern block is segmented into multiple parts that are independently supported by the jig during carving processing. This segmentation reduces the cumulative welding heat input and prevents large-scale distortion while maintaining fixation strength at each segment's attachment portion

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Welding is concentrated at specific attachment portions rather than distributed along the entire periphery. This localized approach minimizes heat-affected zones and prevents distortion that would compromise processing accuracy

Inventive Principle:
Principle #3Local quality

3Ease of manufacture

If marking is used for attachment positioning, then the process is simple, but positioning accuracy in the circumferential direction is not good

Engineering Contradiction:
Improveattachment process simplicityVSAvoidpositioning accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The marking-based positioning system is replaced with a mechanical positioning system using positioning pins and positioning grooves. This substitution provides precise circumferential positioning through direct mechanical engagement while maintaining ease of the attachment process

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Manufacturing precision

If lapping operation is performed to maintain machine processing accuracy, then attachment accuracy is achieved, but the process becomes complicated and requires manual work

Engineering Contradiction:
Improveattachment accuracyVSAvoidattachment process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Positioning pins and positioning grooves are provided in advance on the jig and pattern block respectively, enabling accurate positioning before attachment. This preliminary mechanical positioning eliminates the need for post-attachment lapping operations to achieve required accuracy

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2949443B1Sector mold and method for manufacturing same
Publication Date: 2020.03.04 BRIDGESTONE CORP
  • EP2949443B1 patent drawingFigure 1A~1B
  • EP2949443B1 patent drawingFigure 2A~2B
  • EP2949443B1 patent drawingFigure 3

AI summary

A pattern block can be easily attached to a sector with high positional accuracy, and furthermore, the strength thereof is enhanced. The present invention provides a sector mold constituted by attaching a pattern block (20) to a sector (10), and the sector mold includes: the sector (10) including an embedding groove (12) and holes (14) for positioning pins; and the pattern block (20) including a convex portion (22a) for an embedding groove and positioning pins (24), on a back body surface (20a), corresponding to the embedding groove (12) and the holes (14) for the positioning pins, respectively.