Vacuum Interrupter Spring Nesting for Contact Pressure
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Solution Overview
Problem
Existing vacuum interrupters face challenges in maintaining contact pressure due to dispersion in ceramic tubes and vibrations, especially under uncontrolled atmospheric pressure, which can lead to increased device length when using additional contact springs, compromising compactness.
Innovation Solution
A vacuum interrupter design featuring a compression spring supported by a guide device fixed to the second bottom wall, with the spring ends attached to the movable arcing contact and housed within a sealing bellows, ensuring leaktight fixation and precise contact pressure without increasing the device's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a compression spring is added to maintain contact pressure, then contact pressure stability is improved, but device length increases
Solution Approach 1:
The compression spring is nested within the bellows structure, allowing the spring to be housed inside the existing device envelope without increasing external dimensions. The bellows acts as a container for the spring, enabling the spring's length to be accommodated within the radial depth of the bellows rather than extending the device axially.
Solution Approach 2:
The spring is oriented radially within the bellows structure rather than axially, changing the dimension in which the spring's length is expressed. This allows the contact pressure mechanism to operate in a radial dimension while maintaining compact axial length of the overall device.
2Device complexity
If atmospheric pressure is used to maintain contact pressure, then device complexity is reduced, but contact pressure stability deteriorates under vibration and altitude variations
Solution Approach 1:
The compression spring is pre-loaded to provide a predetermined contact pressure force that compensates for future disturbances such as vibrations and atmospheric pressure variations. The spring is compressed beforehand to store elastic energy that will maintain contact pressure under varying operating conditions.
Solution Approach 2:
The system transitions from relying on atmospheric pressure (external parameter) to using spring compression force (internal parameter). By changing the source of contact pressure from environmental-dependent atmospheric pressure to a controlled mechanical spring force, the system achieves stable contact pressure independent of altitude and atmospheric conditions.
3Ease of manufacture
If ceramic tube dispersion is accommodated, then manufacturing flexibility is improved, but contact pressure precision deteriorates
Solution Approach 1:
The compression spring provides a mechanical feedback mechanism that automatically compensates for variations in ceramic tube length. As the ceramic tube length varies within dispersion tolerances, the spring compression adjusts accordingly to maintain the required contact pressure, eliminating the need for precise ceramic tube manufacturing.
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 design effectively maintains contact pressure while keeping the vacuum interrupter compact, addressing dispersion and vibration issues without the need for additional length, thus enhancing operational reliability and manufacturing efficiency.
Implementation Method 1
a compression spring (11) capable of exerting a contact pressure force on the movable arcing contact (5) in arcing contact closure position
Implementation Method 2
a sealing bellows (9) mounted around the rod and intended to ensure the seal between the inner part of the bulb and the outside of the bulb
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
The present invention relates to a vacuum ampoule of the type comprising an elongated vacuum cartridge, said cartridge having a cylindrical envelope (1) sealed by two ends (2,3) respectively referred to as first and second, in which are housed two arc contacts (4,5) of which one (4), fixed, is integral with one of the aforementioned ends (2), while the other (5), movable, is mounted at the end of a rod (6) mounted to slide axially inside the cartridge, through the other (3) of the ends, referred to as second, between a first position referred to as closed of the ampoule A in which the arc contacts (4,5) are end to end and an open position of the ampoule in which the arc contacts are separated, and a compression spring (11) capable of exerting a contact pressure force on the movable arc contact (5) in the closed position of the arc contacts (4,5).This bulb is characterized in that the aforementioned compression spring (11) is mounted inside the bulb A around the rod (6), being supported by one (11a) of its ends, on the moving arc contact (4), and by its opposite end (11b), on a fixed part (7) relative to the envelope (1) of the bulb, this fixed part ensuring the retention and positioning of the spring (11) inside the bulb A.