Relay Contact Recess for Arc Management
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Solution Overview
Problem
Electromagnetic relays face issues with arc discharge between movable and fixed contacts during contact separation, leading to reduced contact lifetime and adhesion due to decreased contact volume when attempting to lower the level difference between contact surfaces.
Innovation Solution
Incorporating protrusions or recesses on the contact surfaces to mimic a reduced level difference without decreasing the contact volume, allowing arcs to easily move away from the contacts, thus maintaining contact lifetime and preventing adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the height of the movable contact is decreased to lower the level difference between the top part of the movable contact and the attachment face of the contact holding member, then the arc can more easily move from the movable contact to the contact holding member, but the volume of the movable contact decreases, leading to shortened contact lifetime and increased adhesion
Solution Approach 1:
The invention applies local quality by creating a recess only at the specific location where the movable contact attaches to the contact holding member, rather than reducing the overall height of the movable contact. This localized modification allows the arc to easily transition to the contact holding member at the recess location while preserving the full volume and structural integrity of the movable contact, thus maintaining contact lifetime and preventing adhesion.
2Object-affected harmful factors
If the height of the movable contact is decreased to lower the level difference between the top part of the movable contact and the attachment face of the contact holding member, then the arc can more easily move from the movable contact to the contact holding member, but the processing complexity increases and adjustment becomes more difficult
Solution Approach 1:
Instead of modifying the entire movable contact structure by reducing its height, the invention applies a localized recess only at the attachment face. This approach simplifies manufacturing compared to redesigning the whole contact structure, as the recess can be created using standard machining or molding processes applied to a specific area, maintaining ease of manufacture while achieving the arc diversion effect.
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 solution enhances breaking performance by prolonging contact lifetime and preventing adhesion issues without altering the contact volume, while simplifying processing and allowing for easy adjustment of the level difference post-assembly.
Implementation Method 1
electromagnetic relays opening and closing contacts by use of magnetic force caused by electromagnets
Implementation Method 2
when the movable contact moves away from the fixed contact, an arc may occur between the contacts
Data Source
AI summary
A contact device including a fixed contact member having a fixed contact; and a movable contact member which includes a movable contact and is movable between a position where the movable contact is in contact with the fixed contact and a position where the movable contact is away from the fixed contact, a first contact member which is one of the fixed contact member and the movable contact member further including a recess in a surface to which a first contact of the first contact member is provided. The first contact protrudes toward a second contact of a second contact member which is another of the fixed contact member and the movable contact member, and a periphery of the recess at least partially surrounding a periphery of the first contact in a surface perpendicular to a protruding direction of the first contact.