Arc-Extinguishing Cover Engagement for Contactor Arc Gas Release

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Solution Overview

Problem

Existing electromagnetic contactors face issues with arc-extinguishing covers being blown off due to high internal pressure in the arc-extinguishing chamber, leading to inadequate discharge of arc gas and potential cover detachment.

Innovation Solution

The electromagnetic contactor incorporates engaging portions on both the case and arc-extinguishing cover, allowing for secure mounting and controlled release to prevent the cover from being blown off while effectively discharging arc gas, utilizing a combination of weak and strong engagement mechanisms to manage pressure and prevent detachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the arc-extinguishing cover is mounted on the upper case with boss shafts and boss holes, then the cover can be securely mounted, but the cover is likely to be blown off when internal pressure increases due to insufficient discharge of arc gas

Engineering Contradiction:
Improvemounting reliabilityVSAvoidarc gas discharge efficiency
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The engagement mechanism is divided into multiple engaging portions (first, second, and third engaging portions) distributed at different locations on the arc-extinguishing cover and upper case. This segmentation allows different regions to provide different functions: some regions maintain strong engagement for secure mounting, while others allow controlled release for arc gas discharge, resolving the contradiction between mounting reliability and gas discharge efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different engaging portions are designed with different engagement strengths and characteristics. The first and second engaging portions provide strong engagement for secure mounting, while the third engaging portion is configured to engage with the first and second engaging portions in a way that allows controlled release. This local differentiation of engagement quality enables both secure mounting and effective arc gas discharge.

Inventive Principle:
Principle #3Local quality

2Object-generated harmful factors

If the arc-extinguishing cover opens forcefully to discharge arc gas, then gas discharge is improved, but the cover is likely to fall off the upper case

Engineering Contradiction:
Improvearc gas discharge efficiencyVSAvoidmounting reliability
Core Design Contradiction:
Object-generated harmful factorsVSReliability

Solution Approach 1:

The engagement mechanism is divided into multiple engaging portions (first, second, and third engaging portions) distributed at different locations on the arc-extinguishing cover and upper case. This segmentation allows different regions to provide different functions: some regions maintain strong engagement for secure mounting, while others allow controlled release for arc gas discharge, resolving the contradiction between mounting reliability and gas discharge efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different engaging portions are designed with different engagement strengths and characteristics. The first and second engaging portions provide strong engagement for secure mounting, while the third engaging portion is configured to engage with the first and second engaging portions in a way that allows controlled release. This local differentiation of engagement quality enables both secure mounting and effective arc gas discharge.

Inventive Principle:
Principle #3Local quality

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 configuration ensures reliable prevention of the arc-extinguishing cover from being blown off while efficiently discharging arc gas, maintaining mechanical durability and reducing production costs by minimizing attachment space requirements.

Implementation Method 1

when abnormally large current flows through the contact portions of the electromagnetic contactor due to a short-circuit accident or the like, there is a possibility that increase in internal pressure of the arc-extinguishing chamber because of generated arc gas

Methodology Applied
Scientific EffectArc gas generation: Electric Arc

Data Source

PatentEP3979281B1Electromagnetic contactor
Publication Date: 2024.01.10 FUJI ELECTRIC FA COMPONENTS & SYST CO LTD
  • EP3979281B1 patent drawingFigure 1
  • EP3979281B1 patent drawingFigure 2
  • EP3979281B1 patent drawingFigure 3~4B

AI summary

An electromagnetic contactor (1) including: an arc-extinguishing chamber (S) in which a contact portion (6) is disposed; a case (3) having an arc-extinguishing chamber housing portion (9) in which the arc-extinguishing chamber is housed; and an arc-extinguishing cover (7) mounted on the case and configured to cover the arc-extinguishing chamber housing portion, wherein at least one of the case and the arc-extinguishing cover has a first engaging portion (22, 24) and a second engaging portion (23, 25), the other has a third engaging portion (26, 28) configured to engage with the first engaging portion and the second engaging portion, and the arc-extinguishing cover is held to the case in either a first state in which the first engaging portion and the third engaging portion are engaged with each other or a second state in which the second engaging portion is engaged with the third engaging portion.