Spark Plug Insulator Through Hole Bending Prevention

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Solution Overview

Problem

The existing manufacturing methods for spark plug insulators face challenges in using small-diameter press pins, as they tend to bend due to resistance from the green powder, leading to non-straight through holes and increased manufacturing costs.

Innovation Solution

A method that involves arranging the press pin within the cavity before filling with green powder, using a blocking member to minimize resistance, and applying compression molding to form a compact with a straight through hole, allowing for easy extraction of the press pin and reducing bending.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a small-diameter press pin is used to manufacture insulators with smaller diameters, then the insulator diameter is reduced to save space, but the press pin bends due to resistance from green powder

Engineering Contradiction:
Improveinsulator diameterVSAvoidthrough hole straightness
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The press pin is arranged within the cavity before the green powder is filled, allowing the pin to be positioned correctly before compression molding begins. This preliminary positioning prevents bending by ensuring the pin is stable and properly aligned before the resisting force of the green powder acts upon it during compression.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A blocking member is introduced as an intermediary element to block the opening of the cavity during compression molding. This blocking member minimizes the resistance that the green powder exerts on the press pin by controlling the compression process, thereby preventing pin bending while still allowing the formation of the through hole.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the press pin is arranged after powder filling, then the process sequence is simpler, but the press pin bends due to resistance from the green powder

Engineering Contradiction:
Improveprocess sequenceVSAvoidpress pin straightness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The press pin is arranged within the cavity before the green powder is filled, allowing the pin to be positioned correctly before compression molding begins. This preliminary positioning prevents bending by ensuring the pin is stable and properly aligned before the resisting force of the green powder acts upon it during compression.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A blocking member is introduced as an intermediary element to block the opening of the cavity during compression molding. This blocking member minimizes the resistance that the green powder exerts on the press pin by controlling the compression process, thereby preventing pin bending while still allowing the formation of the through hole.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If the press pin moves a long distance during compression molding, then the through hole is formed more completely, but the press pin bends due to increased resistance

Engineering Contradiction:
Improvethrough hole formationVSAvoidpress pin rigidity
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

A blocking member is introduced as an intermediary element to block the opening of the cavity during compression molding. This blocking member minimizes the resistance that the green powder exerts on the press pin by controlling the compression process, thereby preventing pin bending while still allowing the formation of the through hole.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The compression molding parameters are optimized to achieve complete through hole formation while minimizing the distance the press pin needs to move. By adjusting compression force, speed, and duration, the process achieves effective through hole formation with reduced pin displacement, thereby maintaining pin rigidity and preventing bending.

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 enables the production of spark plug insulators with high yield and low manufacturing costs by preventing press pin bending and ensuring straight through holes, even with small diameters.

Implementation Method 1

as a compression molding step, the green powder within the cavity is pressed along with the press pin to obtain a compact

Methodology Applied
Scientific EffectCompression molding: Compression

Implementation Method 2

the green powder within the cavity is pressed along with the press pin to obtain a compact

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

the green insulator is sintered at a temperature of 1400°C to 1650°C. Thereby, a pinhole formed by the press pin becomes the through hole

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP2103402B1Method for manufacturing an insulator for spark plug
Publication Date: 2013.12.18 NITERRA CO LTD
  • EP2103402B1 patent drawingFigure 1
  • EP2103402B1 patent drawingFigure 2
  • EP2103402B1 patent drawingFigure 3

AI summary

A method for manufacturing an insulator for a spark plug is provided. The method includes: a preparing step; a press pin arranging step; a powder filling step after the press pin arranging step; a cavity blocking step after the powder filling step; a compression molding step after the cavity blocking step; a die releasing step after the compression molding step; and a press pin removing step after the die releasing step.