Sealed Contact Device Arc Shielding for Relay Reliability

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Solution Overview

Problem

Hermetically sealed electromagnetic relays face issues with arc impingement on the container and permanent magnet deterioration due to inefficient arc dissipation, leading to short-term arc dissipation capabilities.

Innovation Solution

A sealed contact device with an arc shield member positioned to guide and dissipate arcs generated between moving and stationary contacts, using a gate-type configuration with arm portions and ribs to direct arcs away from the permanent magnet and housing, ensuring efficient and reliable long-term arc dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If permanent magnets are disposed on the outer peripheral surface of the resin container to induce arcs, then arc dissipation function is provided, but the arc impinges onto the inner peripheral surface of the container causing damage and the permanent magnet deteriorates due to heating and rapid cooling

Engineering Contradiction:

Improvearc dissipation functionVSAvoidarc impingement damage to container and permanent magnet

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

An arc shield member made of heat-resistant material is introduced as an intermediary component between the contacts and the permanent magnets/container. This shield member intercepts and dissipates arcs before they can reach the permanent magnets or container, protecting these components from thermal damage while maintaining the arc dissipation function.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The arc shield member is designed with a gate-type structure including a coupling member and arm portions that can be separately assembled. This segmentation allows the shield to be installed within the limited internal space of the resin container without interfering with other components, while still providing comprehensive protection.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If the resin container is used to house all components, then device integration is achieved, but the container suffers from arc-induced damage reducing its durability

Engineering Contradiction:

Improveintegration of components in resin containerVSAvoiddurability of resin container

Core Design Contradiction:

Device complexityVSDuration of action of stationary object

Solution Approach 1:

The arc shield member is installed beforehand within the resin container to provide protective cushioning against arc-induced damage. This pre-positioned shield absorbs the thermal and mechanical stress of arcs, preventing direct impingement on the container and extending its service life.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If permanent magnets are used to generate magnetic force for arc induction, then arc dissipation is achieved, but the magnetic characteristics deteriorate due to repeated heating and cooling cycles

Engineering Contradiction:

Improvearc induction functionVSAvoidmagnetic characteristic stability of permanent magnet

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The arc shield member serves as a thermal barrier between the arc generation zone and the permanent magnets. By intercepting arcs before they reach the magnets, the shield reduces thermal cycling effects, thereby maintaining the magnetic characteristics and extending the operational life of the permanent magnets.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The solution effectively prevents arc-induced damage to the housing and permanent magnet, maintaining reliable arc dissipation for extended periods without compromising mechanical strength or switching operations.

Implementation Method 1

a magnetic force of the permanent magnet

Methodology Applied

Scientific EffectMagnetic force: Magnetic Field

Implementation Method 2

an arc generated between the stationary contact and the moving contact is drawn due to a current conducting between the stationary contact and the moving contact and a magnetic force of the permanent magnet

Methodology Applied

Scientific EffectLorentz force: Lorentz Force

Implementation Method 3

an arc in the housing is drawn... the arc impinges onto and dissipates in the shield member

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 4

the arc heats and rapidly cools a permanent magnet 30, resulting in deterioration

Methodology Applied

Scientific EffectCooling: Cooling

Data Source

PatentUS9748065B2Sealed contact device

Publication Date: 2017.08.29 OMRON CORP

AI summary

A sealed contact device capable of maintaining a function for drawing a generated arc to disappear rapidly and reliably for a long period. An electromagnetic relay includes a housing, a stationary contact and a moving contact which are disposed opposite to each other in the housing, and a pair of permanent magnets and disposed opposite to the stationary contact and the moving contact. An arc generated between the stationary contact and the moving contact is drawn due to a current conducting between the stationary contact and the moving contact and magnetic forces of the permanent magnets. An arc shield member is disposed in a position in which an arc in the housing is induced.