Circuit-Breaker Pole Part Insulation Stress Reduction
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Solution Overview
Problem
Existing methods for producing circuit-breaker pole parts often result in mechanical stress between the vacuum interrupter and the insulating sleeve, require complex assembly processes, and lack efficient insulation solutions, particularly for high-voltage applications.
Innovation Solution
A method involving molding an external insulating sleeve around the vacuum interrupter, using the upper terminal as a mechanical protection and sealing component, and applying a dielectric insulating layer to reduce mechanical stress and enhance insulation, with optional additional insulation layers and flexible connectors for reliable performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vacuum interrupter is fully encapsulated with plastic material during injection molding, then the external dielectric strength is increased and thermal expansion compensation is achieved, but mechanical stress and cracks may occur due to high process temperature and pressure
Solution Approach 1:
The encapsulation is divided into two distinct layers: an inner rubber layer applied to the vacuum interrupter surface, and an outer plastic insulation layer molded around the rubber layer. This segmentation allows each material to perform its optimal function while reducing combined stress effects.
Solution Approach 2:
The patent uses a composite structure combining rubber and plastic materials. The rubber layer provides thermal expansion compensation and stress absorption, while the plastic layer provides external dielectric strength. This composite approach resolves the contradiction between protection and stress resistance.
2Reliability
If the vacuum interrupter is fully encapsulated with plastic material, then insulation performance is improved, but the assembly process becomes complex requiring multiple steps
Solution Approach 1:
The rubber layer is applied to the vacuum interrupter surface before the injection molding process. This preliminary action prepares the surface for molding and ensures proper positioning, simplifying the overall assembly process while maintaining insulation performance.
Solution Approach 2:
The patent combines the rubber layer application and plastic injection molding into an integrated process where the rubber-coated vacuum interrupter is directly placed in the molding device. This merging reduces the number of separate assembly steps while achieving the required insulation performance.
3Manufacturing precision
If high process temperature and pressure are used during injection molding, then the plastic insulation layer is properly formed, but mechanical stress and potential cracks are induced
Solution Approach 1:
The rubber layer is applied beforehand to the vacuum interrupter surface, creating a cushioning layer that absorbs and distributes the mechanical stress from high temperature and pressure during injection molding. This prevents cracks while allowing proper formation of the plastic insulation layer.
Solution Approach 2:
The patent changes the material parameter by introducing a rubber layer with different thermal and mechanical properties than the plastic insulation layer. This parameter change allows the system to withstand high process temperatures and pressures without cracking, while still achieving proper insulation layer formation.
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 approach eliminates mechanical stress, simplifies the assembly process, provides direct sealing without screws, and ensures reliable insulation, enabling efficient production of circuit-breaker pole parts with improved electrical and mechanical stability.
Implementation Method 1
During encapsulating the interrupter by molding under a high process temperature, the liquid rubber solution vulcanizes and forms the intermediate compensating layer as described above
Implementation Method 2
the synthetic material serves as a compensation material for the purpose of compensating for different coefficient of thermal expansion between the vacuum interrupter surface and the surrounding insulating sleeve
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
Method for producing a circuit-breaker pole part by molding an external insulating sleeve (9) with insulation material, mounting a vacuum interrupter insert (8) inside the insulating sleeve (9), electrically connecting the vacuum interrupter insert (8) with an upper electrical terminal (2) and a lower electrical terminal (3) arranged in the wall section of the insulating sleeve (9), with the following production steps: molding the external insulating sleeve (9), wherein only the upper electrical terminal (2) is embedded in the insulation material, coating the vacuum interrupter insert (8) with an extra layer (11 ) made of insulation material for thermo extension compensation, mounting the coated vacuum interrupter insert (8) by screwing on a threaded bolt (10) onto the upper electrical terminal (2).