Self-Aligning End Shield for Vacuum Interrupter Brazing
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Solution Overview
Problem
Existing vacuum interrupters with end shields face challenges in alignment during manufacturing, leading to potential electrical shorts and reduced productivity due to the use of external alignment flanges and ceramic fixtures that slow down furnace run times and interfere with braze joints.
Innovation Solution
A vacuum envelope design featuring an end shield with a flange portion that self-aligns by engaging the inside surface of an end member, eliminating the need for external alignment fixtures and ensuring proper positioning without compromising braze joints, including a V-shaped structure and dimples for secure engagement with the ceramic tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If external alignment flanges and ceramic fixtures are used to align the end shield during manufacturing, then alignment precision is improved, but productivity deteriorates due to slower furnace run times and interference with braze joints
Solution Approach 1:
The end shield incorporates a self-alignment flange that automatically aligns with the ceramic tube during the brazing process without requiring external alignment fixtures. The flange portion of the end shield engages with the outer surface of the ceramic tube, providing self-alignment functionality that eliminates the need for separate alignment tools and speeds up manufacturing while maintaining precision
Solution Approach 2:
The alignment function is extracted from external fixtures and integrated directly into the end shield component itself. The self-alignment flange is built into the end shield structure, removing the need for separate external alignment flanges and ceramic fixtures, thereby simplifying the manufacturing process and improving productivity
2Manufacturing precision
If external alignment fixtures are used during manufacturing, then alignment is improved, but device complexity increases due to additional components and processes
Solution Approach 1:
The alignment function is merged with the end shield component itself through the self-alignment flange. Instead of being a separate external fixture, the alignment feature is integrated into the end shield structure, reducing the total number of components and simplifying the overall device while maintaining alignment precision
3Ease of manufacture
If the end shield is not properly secured in the vacuum interrupter, then ease of manufacture is improved, but reliability deteriorates due to potential electrical shorts
Solution Approach 1:
The self-alignment flange is designed with a geometry that provides inherent positioning and engagement features. The flange portion extends radially outward and engages with the ceramic tube in a way that prevents misalignment and ensures proper securing during the brazing process, providing built-in error prevention that maintains both ease of manufacture and reliability
Solution Approach 2:
The end shield's self-alignment flange automatically positions and secures itself to the ceramic tube during manufacturing without requiring complex external fixtures or multi-step alignment procedures. This self-securing mechanism simplifies manufacturing while ensuring reliable positioning that prevents electrical shorts
Data Source
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AI summary
A vacuum envelope is for a fixed contact mounted on a fixed electrode and a moveable contact mounted on a moveable electrode. The vacuum envelope includes a ceramic tube including a first open end and a second open end. A first end member is secured to the first open end. A second end member includes an inside surface and is secured to the second open end. A self-aligning shield includes a first end having an opening therein, a second open end, an intermediate portion disposed between the first end and the end shield second open end, and a flange portion disposed from the end shield second open end. The flange portion extends outwardly from the intermediate portion and generally back toward the first end. The flange portion includes an edge engaging the inside surface of the second end member, and is normally offset from the ceramic tube.