Switching Device Magnet with Exposed Metal Surface
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Solution Overview
Problem
Conventional switching devices using plastic magnets to diffuse arcs suffer from surface melting due to arc heat, leading to degraded performance and shortened lifetimes, as the melting point of plastic is lower than that of metal magnets.
Innovation Solution
Exposing metallic material to the surface of a plastic magnet, with a composition ratio of plastic resin set to 5% or less, or using a heat shield plate made of metal to protect the plastic magnet, thereby maintaining the high melting point of the metal and preventing surface melting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a plastic magnet is used instead of a metallic magnet, then cost and weight are reduced, but the surface of the plastic magnet melts due to arc heat
Solution Approach 1:
The patent uses a composite structure consisting of a plastic magnet body with a metallic coating layer on its surface. This composite material approach combines the advantages of plastic (low weight, cost-effectiveness) with the advantages of metal (high melting point, arc resistance), resolving the contradiction between weight reduction and surface integrity maintenance under arc heat exposure
Solution Approach 2:
The metallic coating layer acts as an intermediary between the arc heat and the plastic magnet surface. This intermediate layer absorbs and withstands the thermal stress from the arc, preventing direct contact between the high-temperature arc and the plastic material, thereby protecting the plastic magnet from melting while maintaining the overall lightweight structure
2Volume of moving object
If the magnet is disposed close to the arc generation position for downsizing, then the switch size is reduced, but the plastic magnet surface melts more severely due to stronger arc heat influence
Solution Approach 1:
By using a plastic magnet with metallic coating, the patent enables the magnet to be positioned closer to the arc generation point without suffering from severe heat damage. The metallic coating provides thermal protection, allowing compact positioning that reduces overall switch size while maintaining surface integrity under intensified arc heat exposure
Solution Approach 2:
The metallic coating is applied in advance to the plastic magnet surface before the magnet is exposed to arc heat during operation. This preliminary protective measure creates a heat-resistant barrier that prevents the plastic surface from melting when the magnet is disposed close to the arc generation position, counteracting the harmful thermal effects before they can damage the plastic material
3Reliability
If metallic material is exposed to the magnet surface, then arc diffusion performance is maintained, but manufacturing complexity increases
Solution Approach 1:
The patent replaces complex mechanical or assembly-based solutions (such as separate metal components attached to the magnet) with a coating process that directly deposits metallic material onto the plastic magnet surface. This substitution of manufacturing approach maintains the exposed metal surface necessary for arc diffusion performance while simplifying the overall manufacturing process by integrating the protective and functional layers in a single coating operation
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 surface melting of the plastic magnet, maintaining arc diffusion performance and extending the switch's operational lifespan without compromising on cost or durability.
Implementation Method 1
a magnet configured to generate a magnetic field in a direction orthogonal to a direction of the arc
Implementation Method 2
a force is caused to act on electrons constituting the arc to encourage diffusion of the arc
Implementation Method 3
the metal is exposed to the surface of the magnet... the surface of the magnet is not melted by the heat of the arc
Data Source
AI summary
A switching device that causes a force to act on an arc to diffuse the arc, has a magnet that generates a magnetic field in a direction orthogonal to a direction of the arc, the arc being generated at moment at which a movable member is brought into contact with or separated from a contact of a fixed member to switch between electric conduction and electric cutoff. The magnet is a plastic magnet in which metal is exposed to a surface of the magnet.