Medium-Voltage Pole Part Threaded Fixation to Reduce Housing Stress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current fixation methods for pole parts in medium voltage switchgear using screws and integrated female threads can cause damage to the insulating housing due to mechanical stress, leading to a risk of breakage.
Innovation Solution
The pole part incorporates a casted or moulded axial externally threaded section made of insulating material, allowing for secure fixation using a screw nut or screw, which is integrated during manufacturing, reducing mechanical stress and eliminating the need for dowels, with optional reinforcement fibers or conductive elements for enhanced mechanical and capacitive shielding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If screws are inserted into the pole part at multiple fixation points using integrated female threads, then the pole part can be securely fixed to the support element, but mechanical stress concentrates at the thread areas causing damage and risk of breakage to the insulating housing
Solution Approach 1:
The fixation function is segmented from the insulating housing by introducing a separate fixation element (metal insert or reinforcement fiber) that carries the threading. This separates the mechanical stress-bearing function from the insulating housing, allowing the housing to remain intact while providing secure fixation through the dedicated fixation element.
Solution Approach 2:
A fixation element acts as an intermediary between the insulating housing and the screw. This intermediary (metal insert embedded in the housing or reinforcement fiber) absorbs the mechanical stress of threading, preventing direct damage to the insulating housing while enabling secure mechanical fixation.
2Ease of operation
If integrated female threads are implemented into the bulk of the insulating housing, then fixation is achieved, but the core area of the insulating housing is damaged
Solution Approach 1:
The fixation capability is segmented into a separate fixation element rather than being integrated into the housing bulk. The metal insert or reinforcement fiber provides the threading function independently, preserving the housing integrity while enabling easy screw fixation operation.
Solution Approach 2:
The solution uses composite construction by embedding a metal fixation element within the insulating housing material. This composite structure combines the electrical insulation properties of the housing with the mechanical strength and threading capability of the metal insert, achieving both fixation capability and housing integrity.
3Strength
If dowels are used for fixation, then the pole part can be secured, but additional components and assembly steps are required
Solution Approach 1:
The fixation element combines multiple functions into a single component: it provides structural reinforcement, creates the threading interface, and enables screw fixation all in one element. This eliminates the need for separate dowels and reduces assembly complexity while maintaining strong fixation.
Solution Approach 2:
The fixation element serves multiple purposes simultaneously: it reinforces the insulating housing, provides the threading structure for screws, and acts as the mechanical anchor for fixation. This multi-functionality replaces what would otherwise require multiple separate components like dowels and threaded inserts.
Data Source
Figure 1
AI summary
The invention relates to a pole part for medium voltage switchgear, with a vacuum interrupter embedded in an insulating housing made of epoxy-, bulk moulded component- or thermoplastic or other plastic material, with a bottom part provided with mechanical fixation means, in order to fix the polepart on a support element, and a method for manufacturing the same, according to the preamble of claim 1, 8 and 9. In order to reduce mechanical stress and the risk of a break of the insulating housing, the invention is, that the bottom part (2) of the pole part (1) is provided with a casted on, or moulded on axial externally or internally threaded section (5), made of insulating material.