Switch With Segmented Contacts To Prevent Insulation Failure
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Solution Overview
Problem
Conventional switches with normally-closed fixed contacts experience insulation failure due to repetitive opening and closing movements, which lead to metallic abrasion and resin carbonization, degrading insulation performance.
Innovation Solution
The switch design incorporates a normally-closed fixed contact unit and a common contact unit with sequentially formed conductive and insulating regions, along with a movable contact that slides from the conductive to the insulating region, increasing the insulation distance and preventing resin carbonization by ensuring one region remains clean during switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the slider slides on the conductive region and insulating region of the normally-closed fixed contact during repetitive opening and closing operations, then the switching function is achieved, but metallic abrasion powders are deposited and insulation performance degrades
Solution Approach 1:
The fixed contact is divided into multiple contact units (normally-closed fixed contact unit and common contact unit), each with separate conductive and insulating regions. The movable contact slides on both units simultaneously, segmenting the sliding path to distribute wear and extend the insulation distance, thereby reducing harmful abrasion powder deposition and improving insulation performance.
2Reliability
If arc discharge occurs between the normally-closed fixed contact and slider during high-capacity current switching, then the switching function is achieved, but the insulating resin is carbonized and insulation performance degrades
Solution Approach 1:
The contact system is segmented into multiple contact units with separate arc discharge zones. When arc discharge occurs during high-capacity current switching, it is confined to specific conductive regions of individual contact units rather than affecting the entire insulating structure. This segmentation prevents widespread resin carbonization and maintains insulation performance.
Solution Approach 2:
The insulating regions act as intermediary barriers between the conductive contact surfaces. During arc discharge, these insulating regions protect the main insulating resin from direct carbonization by providing a protective zone that absorbs and dissipates arc energy, preventing harmful resin degradation.
3Reliability
If the insulation distance is increased by adding a common contact unit with sequential conductive and insulating regions, then insulation performance is improved, but the device complexity increases
Solution Approach 1:
The normally-closed fixed contact unit and common contact unit are merged into a single integrated fixed contact structure. Both contact units share the same insulating base and are positioned adjacent to each other, allowing the movable contact to slide on both simultaneously. This merging approach extends the insulation distance without proportionally increasing device complexity.
Solution Approach 2:
The movable contact serves multiple functions by simultaneously contacting both the normally-closed fixed contact unit and the common contact unit. It performs switching operations for both contact pairs while maintaining continuous sliding motion, thereby achieving enhanced insulation performance without requiring separate sliding mechanisms for each contact unit.
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 enhances insulation performance by lengthening the insulation distance and maintaining one region free from resin carbonization, thereby reducing the likelihood of insulation failure.
Implementation Method 1
the slider slides on the conductive region and the insulating region of the normally-closed fixed contact
Implementation Method 2
The repetitive opening and closing movement abrades the conductive region, and metallic abrasion powders are deposited
Implementation Method 3
An arc discharge is generated between the normally-closed fixed contact and the movable contact in the case of the opening and closing operation of a high-capacity current
Implementation Method 4
An insulating resin or a grease, which constitutes the insulating region, is carbonized
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
One aspect of the present invention provides a switch in which an insulation failure is hardly generated. In the switch, a conductive region and an insulating region are formed in a sliding surface of a slider in a normally-closed fixed contact unit in the order toward a Z-direction, a conductive region and an insulating region are formed in a sliding surface of the slider in a common contact unit in the order toward the Z-direction, and the slider slides from the conductive regions to the insulating regions to switch from a closed state to an opened state.