DC Relay Mover Assembly With Magnetic Circuit for Contact Stability

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Solution Overview

Problem

Direct current relays face issues with unintended separation of contacts due to electromagnetic repulsive forces, which can lead to unreliable power transmission in applications like electric vehicles.

Innovation Solution

The design incorporates an upper yoke and a lower yoke forming a magnetic circuit to offset the electromagnetic repulsive force, with a contact pressure spring between the lower yoke and the mover support, ensuring stable contact pressure and preventing unintended separation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the movable contact receives contact pressure from a contact pressure spring to prevent separation, then contact stability is improved, but the electromagnetic repulsive force between fixed and movable contacts increases, causing stronger separation tendency

Engineering Contradiction:
Improvecontact stabilityVSAvoidelectromagnetic repulsive force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The movable contact assembly is segmented into multiple components: movable contact, mover holder, upper yoke, lower yoke, and mover support. This segmentation allows independent optimization of each component's function, particularly enabling the yokes to generate offsetting magnetic forces while the contact pressure spring maintains contact stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The upper yoke and lower yoke generate electromagnetic forces that act as counterforces to offset the electromagnetic repulsive force between the fixed and movable contacts. This counterbalancing approach directly addresses the technical contradiction by providing an opposing force mechanism.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

2Force

If the distance between fixed core and movable core is increased to provide contact pressure, then contact pressure is improved, but the actuator structure becomes more complex and longer

Engineering Contradiction:
Improvecontact pressureVSAvoidactuator structure
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The patent merges the contact pressure generation function with the existing actuator structure by utilizing the over-travel of the movable core. The movable core's movement beyond the engagement point with the fixed core naturally generates contact pressure on the movable contact, eliminating the need for separate complex pressure generation mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The movable core serves multiple functions: it is actuated by the electromagnetic force to close the circuit, and simultaneously its over-travel provides the contact pressure needed to maintain reliable contact. This multi-functionality reduces overall device complexity while achieving the desired contact pressure.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If contact pressure spring is added to maintain contact pressure, then contact reliability is improved, but device complexity and space requirements increase

Engineering Contradiction:
Improvecontact reliabilityVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The contact pressure spring provides dynamic contact pressure that automatically adjusts to the electromagnetic repulsive forces. The spring compresses and expands based on the operational conditions, maintaining optimal contact pressure without requiring complex control mechanisms or additional components.

Inventive Principle:
Principle #15Dynamics

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 effectively maintains contact between the fixed and movable contacts, preventing unintended separation and ensuring reliable power transmission.

Implementation Method 1

an upper yoke and a lower yoke respectively disposed above and below the movable contact to generate an electromagnetic force

Methodology Applied
Scientific EffectElectromagnetic force: Electromagnet

Implementation Method 2

the upper yoke and the lower yoke form a magnetic circuit to offset an electromagnetic repulsive force

Methodology Applied
Scientific EffectMagnetic circuit: Magnetism

Data Source

PatentEP3846194B1Direct current relay
Publication Date: 2024.05.15 LS ELECTRIC CO LTD
  • EP3846194B1 patent drawingFigure 1
  • EP3846194B1 patent drawingFigure 2
  • EP3846194B1 patent drawingFigure 3

AI summary

The present invention relates to a direct current relay and, more specifically, to a direct current relay having a mover assembly having improved contact pressure. A direct current relay according to an aspect of the present invention, comprising: a pair of fixed contactors and a movable contactor which is moved up and down by an actuator to come into contact with or be separated from the pair of fixed contactors, comprises: a mover support disposed below the movable contactor and connected to the actuator by a shaft; a mover holder disposed above the movable contactor and fixed to the mover support; an upper yoke and a lower yoke disposed above and below the movable contactor to generate an electromagnetic force, respectively; and a contact pressure spring disposed between the lower yoke and the mover support, wherein the upper yoke and the lower yoke form a magnetic path to offset an electron repulsive force generated between the fixed contactors and the movable contactor.