Electromagnetic Switch Contact Insulator for Longer Creepage Distance

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Solution Overview

Problem

Electromagnetic switches in vehicles face insulation failures between contacts and coils, risking electric shock due to high voltage transmission to low-voltage devices, necessitating enhanced insulation capabilities.

Innovation Solution

The use of a plastic insulating part with spaced protrusions on its outer wall increases the creepage distance, enhancing insulation between the moving contact and the coil, and incorporating a contact guide sleeve and U-shaped bracket for improved contact pressure and synchronization, thereby reducing the risk of insulation failure and electric shock.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a simple insulating structure is used between the contact and coil, then the device complexity is reduced, but the insulation capability deteriorates due to insufficient creepage distance

Engineering Contradiction:
Improveinsulation capabilityVSAvoidinsulating part structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The insulating part extends in the axial direction to increase the creepage distance between the contact and coil. By utilizing the axial dimension rather than only radial extension, the patent achieves sufficient insulation distance while maintaining a compact radial profile, thus improving insulation capability without excessive structural complexity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The insulating part is designed with a stepped structure comprising multiple segments with different diameters along the axial direction. This segmentation allows the insulating part to provide sufficient creepage distance while optimizing material usage and maintaining manufacturing simplicity, resolving the contradiction between insulation capability and structural complexity

Inventive Principle:
Principle #1Segmentation

2Reliability

If the insulating part extends axially to increase creepage distance, then the insulation capability is improved, but the volume of the electromagnetic switch increases

Engineering Contradiction:
Improveinsulation capabilityVSAvoidelectromagnetic switch volume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The insulating part采用 stepped structure with multiple segments of different diameters along the axial direction. This segmentation allows the insulating part to provide sufficient creepage distance while optimizing material usage and maintaining manufacturing simplicity, resolving the contradiction between insulation capability and structural complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The insulating part extends in the axial direction to increase the creepage distance between the contact and coil. By utilizing the axial dimension rather than only radial extension, the patent achieves sufficient insulation distance while maintaining a compact radial profile, thus improving insulation capability without excessive structural complexity

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 improves insulation capabilities, reducing the risk of electric shock and extending the service life of the contacts by increasing the creepage distance and ensuring consistent contact operation, thus ensuring safe and reliable operation of electromagnetic switches in vehicles.

Implementation Method 1

An operating principle of the electromagnetic switch is that a current flows through a coil to generate a magnetic field, so that a contact is connected or disconnected, to control a load

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4117008B1Contact device and electromagnetic switch
Publication Date: 2024.07.31 HUAWEI DIGITAL POWER TECH CO LTD
  • EP4117008B1 patent drawingFigure 1
  • EP4117008B1 patent drawingFigure 2
  • EP4117008B1 patent drawingFigure 3

AI summary

This application relates to an electromagnetic switch, including a driving apparatus and a contact apparatus. The contact apparatus includes a moving contact assembly, a chamber, and two spaced fixed contacts disposed on a top part of the chamber. The moving contact assembly includes an insulating part, a push rod, a moving contact, and an elastic part. One end of the push rod is mounted on the driving apparatus, and the other end of the push rod is mounted on the insulating part. The moving contact is mounted on one side that is of the insulating part and that is back to the push rod. The elastic part is clamped between the insulating part and the moving contact, so that the moving contact is in contact with or separated from the pair of fixed contacts under the action of the push rod. The insulating part is a plastic part, and a plurality of spaced protrusions are disposed on an outer wall that is of the insulating part and that is located between the moving contact and the push rod. In this way, protrusion structures similar to electrical insulator structures are disposed on the outer wall of the insulating part, to increase a creepage distance on a material surface, and improve an insulation capability of the electromagnetic switch.