Electromagnetic Relay Arc Extinction via Magnetic Loop

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Solution Overview

Problem

Conventional electromagnetic relays require strong permanent magnets to concentrate magnetic flux at the contact switching unit, leading to increased costs and magnetic flux leakage, which complicates early arc extinction during contact opening/closing.

Innovation Solution

The electromagnetic relay incorporates a connection member with high magnetic permeability to form a closed magnetic loop, enhancing magnetic flux concentration at the contact open/close position, and includes a recessed portion for the arc extinguishing member to maintain insulation and direct the arc current effectively, reducing magnetic flux leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single permanent magnet is arranged on the upper side of the contact switching unit to generate a magnetic field, then the arc current can be extended toward the side and extinguished, but the magnetic flux easily leaks to the peripheral space and cannot concentrate at the contact switching unit, requiring a stronger permanent magnet which increases cost

Engineering Contradiction:
Improvearc extinguishing capabilityVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The connection member is divided into multiple projecting sections (first, second, third, and fourth projecting sections) that are positioned at different locations around the contact switching unit. Each projecting section carries a permanent magnet, creating multiple localized magnetic fields that work together to extinguish arcs while concentrating magnetic flux where needed, preventing leakage to peripheral spaces.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection member with high magnetic permeability acts as an intermediary that guides and concentrates magnetic flux between the permanent magnets and the contact switching unit. This intermediary structure ensures that magnetic flux is directed precisely where needed for arc extinguishing while preventing leakage to surrounding areas, allowing the use of smaller, less expensive permanent magnets.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If a single permanent magnet is used to generate a magnetic field for arc extinction, then the structure is simple, but the magnetic flux cannot concentrate at the contact switching unit and leaks to peripheral space

Engineering Contradiction:
ImprovestructureVSAvoidmagnetic flux leakage
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

Instead of using a single permanent magnet, the invention segments the magnetic field generation into multiple permanent magnets positioned at different projecting sections of the connection member. This segmentation allows magnetic flux to be concentrated at specific locations around the contact switching unit while preventing leakage to peripheral spaces, achieving both structural simplicity and energy efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different projecting sections of the connection member are positioned at different locations (upper side, lower side, left side, right side of the contact switching unit) to create localized magnetic fields where arcs are most likely to occur. This local quality approach ensures magnetic flux is concentrated exactly where needed for arc extinguishing while preventing waste leakage to areas where it is not needed.

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 early arc extinction by concentrating magnetic flux at the contact open/close position, reducing the need for strong magnets and minimizing magnetic flux leakage, thereby lowering costs and improving operational efficiency.

Implementation Method 1

The magnetic field generated from the permanent magnet configures a closed loop through a connection member having high magnetic permeability compared to the surrounding atmosphere

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

connection member having high magnetic permeability compared to the surrounding atmosphere

Methodology Applied
Scientific EffectMagnetic permeability: Ferromagnetism

Implementation Method 3

the magnetic flux can be concentrated at the contact open/close position

Methodology Applied
Scientific EffectMagnetic flux concentration: Magnetic Field

Implementation Method 4

the influence of the magnetic field by the arc extinguishing member can be sufficiently acted on the arc current generated at the time of contact opening/closing, and the arc current can be sufficiently stretched to the upper side

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP2688084B1Electromagnetic relay
Publication Date: 2019.04.10 OMRON CORP
  • EP2688084B1 patent drawingFigure 1
  • EP2688084B1 patent drawingFigure 2
  • EP2688084B1 patent drawingFigure 3

AI summary

An electromagnetic relay is provided with: a contact switching unit formed by arranging at least two contact groups, each comprising a pair of contacts that can touch and separate, in parallel with each other and perpendicular to the touch/separation direction of the contacts; an electromagnet block that drives the contact switching unit to open and close the contacts; and an arc-extinguishing member comprising a connection member made from a magnetic material and formed by the connection, via a middle part, of protrusions that respectively protrude from both sides of the middle part in the direction of the parallel arrangement of the contact groups and between the contact groups, and also comprising permanent magnets respectively disposed at least on the opposing positions of the protrusions located on both sides of the middle part.