Vacuum Interrupter Terminal Pressure Protection

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Solution Overview

Problem

The high pressure during thermoplastic injection moulding poses a risk of mechanical deformation to the metal cover of vacuum interrupters and requires strong construction and fixation of the upper terminal to prevent deformation, whereas existing methods either result in excessive stress or necessitate additional, costly protection mechanisms.

Innovation Solution

A pressure protecting element, which also functions as a heat distribution element, is integrated into the terminal and fixed at the upper part of the vacuum interrupter before moulding, allowing for fixation forces to be transmitted only through the terminal, using solutions such as screw fixation, movable elements, or separate protection and current carrying parts, to mitigate pressure-induced deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If thermoplastic injection moulding is used to embed the vacuum interrupter, then the filling and packing speed is very fast, but the high pressure causes mechanical deformation of the metal cover

Engineering Contradiction:
Improvefilling and packing speedVSAvoidmetal cover deformation
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The terminal is divided into two functional parts: a current carrying part (copper/aluminum) and a pressure protecting part (polymer material). This segmentation allows the pressure protecting part to absorb injection forces while the current carrying part maintains electrical function, preventing metal cover deformation during fast thermoplastic injection moulding.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The terminal uses composite construction combining metal (copper or aluminum) for electrical conductivity and polymer material for pressure protection. This composite structure enables the terminal to simultaneously conduct electricity and protect the vacuum interrupter from high injection pressures while maintaining fast filling and packing speeds.

Inventive Principle:
Principle #40Composite materials

2Strength

If the metal cover thickness is increased to withstand high pressure, then the pressure resistance is improved, but the production cost increases

Engineering Contradiction:
Improvepressure resistanceVSAvoidmetal cover thickness
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The terminal is segmented into current carrying and pressure protecting functions. The pressure protecting part made of polymer material absorbs injection forces, allowing the metal cover to maintain thin thickness while still providing adequate pressure resistance during thermoplastic injection moulding.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pressure protecting part of the terminal acts as an intermediary element between the injection system and the metal cover. It absorbs and distributes the high injection pressures, protecting the thin metal cover from direct mechanical stress while maintaining cost-effectiveness.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If additional protection mechanisms are added to protect the vacuum interrupter, then the protection level is improved, but the device complexity increases

Engineering Contradiction:
Improveprotection levelVSAvoidnumber of additional components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The protection function is merged into the terminal structure itself through the pressure protecting part. This integration eliminates the need for separate protection caps or additional fixation mechanisms, maintaining high reliability while minimizing device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The terminal serves multiple functions: electrical connection (current carrying part), mechanical protection (pressure protecting part), and structural support. This multi-functionality provides comprehensive protection for the vacuum interrupter without requiring additional specialized components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Strength

If strong fixation of the upper terminal is implemented, then the fixation strength is improved, but the device complexity increases

Engineering Contradiction:
Improvefixation strengthVSAvoidfixation mechanism complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The fixation function is merged into the terminal structure through integrated fixation elements (protrusions, recesses, threading). This integration provides strong fixation of the upper terminal while avoiding the need for separate fixation mechanisms, maintaining simplicity.

Inventive Principle:
Principle #5Merging (Combining)

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 effectively protects the vacuum interrupter from mechanical deformation and ensures secure fixation of the upper terminal within the mould, reducing the need for additional protection and allowing for efficient thermoplastic injection moulding without compromising the integrity of the vacuum interrupter.

Implementation Method 1

the pressure protecting element is used or implemented coincidentially as a heat distribution element. According to the invention the pressure protecting element is an integral part of the terminal, which has to be fixed at the upper part of the vacuum interrupter before inserting it completely into the mould

Methodology Applied
Scientific EffectPressure distribution: Pressure Gradient

Implementation Method 2

the so prepared vacuum interrupter will be fixed in the mould by fixing elements, which transmit the fixation forces only at the aforesaid terminal and the aforesaid protection element of the vacuum interrupter

Methodology Applied
Scientific EffectMechanical fixation: Mechanical Fastener

Data Source

PatentEP2278603B1Method of manufacturing a current terminal for embedded pole part
Publication Date: 2018.09.12 ABB (SCHWEIZ) AG
  • EP2278603B1 patent drawingFigure 1
  • EP2278603B1 patent drawingFigure 2
  • EP2278603B1 patent drawingFigure 3

AI summary

The invention relates to a Method of manufacturing a current terminal for embedded pole part, in which a vacuum interrupter will be moulded by a isolating coverage in a hot and pressure injection process, and pole part itself, in accordance with the preamble of patent claim 1 and 6 . It is an object of the invention, that at the position of the upper electric terminal at the fixed contact side of the vacuum interrupter a pressure protecting element is placed into the mould, at least close to the upper part the fixed contact side of the vacuum interrupter and/or together with it, and that the protecting and reinforcement element and the terminal as well as the vacuum interrupter will be embedded by injection moulding.