Conductive Bellows Vacuum Bulb for Simpler Current Transfer

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Solution Overview

Problem

Conducting electric current between electrodes in a vacuum bulb is difficult and requires additional parts that can cause malfunctions, making existing vacuum bulbs complex, bulky, and costly to manufacture.

Innovation Solution

The vacuum bulb design incorporates a conductive bellows made of stainless steel with a copper coating or laminated with copper, which conducts electric current directly from outside to the movable electrode, eliminating the need for additional conductive wires or joints, and allows a portion of the electrode rod to be insulating, reducing complexity and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional conductive wires or joints are used to conduct current between electrodes, then electric current conduction is achieved, but device complexity increases and reliability decreases

Engineering Contradiction:
ImprovereliabilityVSAvoidcomplexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The bellows is designed to perform multiple functions simultaneously: it provides sealing between the vacuum interior and exterior, enables linear movement of the movable electrode, and conducts electric current. This merging of sealing, movement, and conduction functions into a single component eliminates the need for separate conductive wires or joints, thereby reducing device complexity and improving reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bellows serves as a multi-functional element that combines the roles of a flexible seal, a movement guide for the electrode, and an electrical conductor. By making the bellows universal in its functionality, the patent eliminates the need for additional dedicated conductive components, thus simplifying the overall device structure and reducing potential failure points.

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

2Ease of manufacture

If additional conductive parts are added to conduct current, then current conduction is enabled, but manufacturing cost increases

Engineering Contradiction:
Improvemanufacturing costVSAvoidnumber of parts
Core Design Contradiction:
Ease of manufactureVSQuantity of substance

Solution Approach 1:

The bellows integrates conduction, sealing, and movement functions into one component, eliminating the need for separate conductive wires, joints, or connectors. This reduction in the number of parts directly lowers manufacturing costs by reducing material usage, assembly steps, and quality control requirements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

By designing the bellows as a multi-functional component that handles sealing, movement, and conduction simultaneously, the patent reduces the total quantity of substances and parts needed. This universal approach simplifies manufacturing processes and reduces overall production costs.

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

3Object-affected harmful factors

If the rod of the second electrode is made entirely conductive, then current conduction is simplified, but local field disturbances occur

Engineering Contradiction:
Improvefield disturbancesVSAvoidelectrode structure
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The rod of the second electrode is designed with non-uniform electrical properties: the portion inside the vacuum bulb is made conductive to enable current conduction, while the portion outside the vacuum bulb is made insulating to prevent local field disturbances. This local differentiation of material properties allows the electrode to perform its conduction function while minimizing harmful electromagnetic effects in the external environment.

Inventive Principle:
Principle #3Local quality

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 design results in a more compact, less expensive vacuum bulb with improved reliability by eliminating the need for additional conductive parts, ensuring efficient electric current conduction without local field disturbances.

Implementation Method 1

The vacuum bulb includes a bellows made of stainless steel, copper and/or copper alloy... the bellows is made of stainless steel laminated with copper... the copper coating has a thickness greater than 0.05 millimeters

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3968350B1Vacuum bulb for cut-off device
Publication Date: 2025.11.12 SCHNEIDER ELECTRIC IND SAS
  • EP3968350B1 patent drawingFigure 1
  • EP3968350B1 patent drawingFigure 2
  • EP3968350B1 patent drawingFigure 3

AI summary

Vacuum bulb (1) for a switching device comprising: - a first electrode (5) and a second electrode (6) each comprising a contact part (8), the second electrode (6) being movable along an axial direction (X) relative to the first electrode (5) between a closed position and an open position, and - a bellows (10) disposed around the rod (7) of the second electrode (6), the bellows (10) being adapted to conduct an electric current between the outside of the vacuum bulb (1) and the contact part (8) of the second electrode (6) when the second electrode (6) is in the closed position.