Vacuum Interrupter Contact Joint With Ridge Force-Fit Bonding
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Solution Overview
Problem
The connection between the contact rod and contact piece in vacuum switching tubes is subject to high mechanical stresses during operation, and the quality of the connection cannot be inspected after manufacturing due to the components being inside the finished vacuum tube.
Innovation Solution
A force-fit connection is established between the contact rod and contact piece using ridges that rise perpendicular to the longitudinal axis, ensuring correct positioning and maintaining the components in place during bonding, followed by a metallurgical bond using solder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the contact rod and contact piece are connected with a force-fit connection using ridges, then the mechanical stability and positioning accuracy are improved, but the device complexity increases
Solution Approach 1:
The connection interface is segmented into ridges on one component that engage with corresponding grooves or recesses on the other component. This segmentation allows the force-fit connection to be achieved through distributed contact points rather than a single complex joint, improving mechanical stability while keeping individual ridge features relatively simple
Solution Approach 2:
The ridges are pre-formed on the contact rod or contact piece before assembly. This preliminary action ensures that when the components are joined, the force-fit connection is automatically established through the pre-positioned ridges, eliminating the need for complex real-time adjustment mechanisms during assembly
2Ease of manufacture
If the contact rod and contact piece are soldered together without force-fit connection, then the manufacturing process is simpler, but the connection quality and reliability deteriorate under high mechanical stress
Solution Approach 1:
The invention merges two connection mechanisms: the force-fit mechanical connection provided by ridges and the metallurgical bond from soldering. The ridges provide immediate mechanical stability and positioning, while the solder creates a permanent metallurgical bond, together achieving both ease of manufacture and high connection reliability
Solution Approach 2:
The connection system uses a composite approach combining mechanical elements (ridges made of conductive material) with metallurgical bonding (solder joint). This composite connection method leverages the strengths of both mechanical interlocking and metallurgical bonding to achieve superior reliability under mechanical stress while maintaining manufacturability
3Area of stationary object
If the contact piece has a larger cross-section than the contact bar, then the contact area and load distribution are improved, but the manufacturing cost increases due to use of mechanically resistant materials
Solution Approach 1:
The contact piece is designed with locally optimized properties: it has a larger cross-section at the contact area to distribute arc stress, while the connecting portion that interfaces with the contact rod uses cost-effective materials and simple ridge features. This local differentiation allows the contact area to provide adequate stress distribution without requiring expensive mechanically resistant materials throughout the entire component
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 force-fit connection ensures a high-quality bond with improved stability and reliability, preventing slipping and ensuring a uniform force distribution, thereby enhancing the mechanical integrity of the contact.
Implementation Method 1
They are then placed in a vacuum soldering furnace, the furnace is evacuated, and the loose or detachable components are permanently joined by heating, thus creating a vacuum inside the tube.
Implementation Method 2
the components are first detachably connected or placed on top of each other without any connection. They are then placed in a vacuum soldering furnace, the furnace is evacuated, and the loose or detachable components are permanently joined by heating
Data Source
Figure 1
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AI summary
The invention relates to a contact (1) for a vacuum interrupter (1) of a low-, medium- or high-voltage switchgear, and to a production method for such a contact (1). The contact (1) comprises a contact bar (2) composed of a first electrically conductive material extending along a longitudinal axis (13) of the contact (1), and a contact piece (3) composed of a second electrically conductive material fastened to an end face of the contact bar (2). The contact bar (2) and the contact piece (3) are integrally bonded to one another at a connecting face. According to the invention, at least one of either the contact bar (2) or the contact piece (3) has a wall (8) which delimits the connecting face, rises perpendicularly to the longitudinal axis (13) and is arranged such that the contact piece (3) and the contact bar (2) are also frictionally connected to one another by a force acting transversely to the longitudinal axis (13) between the contact piece (3) and the contact bar (2).