Vacuum Switch Auxiliary Path Shielding for Dielectric Strength
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Solution Overview
Problem
Vacuum switching devices face challenges in achieving sufficient external withstand voltage and contact pressure force while maintaining a simplified structure, particularly in applications where high currents are not consistently required, and the metallization edge is a weak point for dielectric strength.
Innovation Solution
A vacuum switching device with a housing body made of electrically insulating material, featuring a stationary and movable electrical contact, a plain bearing with conductive material for dielectric shielding and spring support, and a compact design that integrates dielectric control and contact force generation, including a bellows and spirally extending slots for resilient mounting and centering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the ceramic length is sufficiently dimensioned in air or gaseous insulating media are used, then external dielectric strength is improved, but device complexity and volume increase
Solution Approach 1:
A metallic shield is introduced as an intermediary component between the ceramic housing and the external environment. This shield acts as a field-shaping element that redistributes the electric field around the metallization edge, preventing field concentration and enhancing dielectric strength without requiring increased ceramic dimensions or complex insulation structures.
Solution Approach 2:
The metallic shield is strategically positioned only at the critical metallization edge region where field concentration occurs. This localized shielding approach provides dielectric enhancement precisely where needed, avoiding the need to increase the overall ceramic length or add comprehensive insulation throughout the entire device.
2Force
If additional externally applied closing forces (springs) are used, then contact pressure is improved, but device complexity increases
Solution Approach 1:
The metallic shield is merged with the spring support structure, combining two previously separate functions into a single integrated component. The shield serves both as an electric field-shaping element for dielectric enhancement and as a mounting structure for the closing spring, thereby providing contact pressure without adding separate complex force generation mechanisms.
Solution Approach 2:
The metallic shield performs multiple functions simultaneously: it shapes the electric field to enhance dielectric strength, provides structural support for the closing spring, and contributes to the mechanical force generation system. This multi-functionality eliminates the need for separate dedicated components for each function.
3Strength
If the plain bearing is made electrically conductive for dielectric shielding, then external dielectric strength is improved, but the bearing material selection and manufacturing complexity increase
Solution Approach 1:
The plain bearing is constructed as a composite structure combining electrically conductive material (for dielectric shielding) with low-friction bearing surfaces. This composite approach allows the bearing to simultaneously provide mechanical support with minimal friction and electrical shielding functionality, overcoming the limitation of single-material bearings that cannot fulfill both requirements effectively.
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 solution enhances dielectric strength and contact pressure force through a compact and integrated design, ensuring reliable operation in a bypass current path without the need for large springs, suitable for applications with varying current demands.
Implementation Method 1
The sliding bearing (5) comprises an electrically conductive material and at least partially dielectrically shields the housing body (2). The sliding bearing (5) at least partially electrically shields the flange (8)
Implementation Method 2
a spring element (7) which presses the movable electrical contact (4) towards the stationary electrical contact (3)
Implementation Method 3
a bellows (15) arranged coaxially around the spring element (7) or formed by the spring element (7)
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a vacuum switch device (1) comprising a housing body (2), a stationary electrical contact (3) and a moving electrical contact (4), which is arranged within the housing body (2) and such that it can move relative to said housing body (2) in such a way that, with the movement thereof towards the stationary electrical contact (3), it forms an electrical contact with same and it interrupts the electrical contact with a movement away from the stationary electrical contact (3). A sliding bearing (5) provides sliding support for the moving electrical contact (4) for the movement thereof towards and away from the stationary electrical contact (3). The sliding bearing (5) has an electrically conductive material and at least partially electrically insulates the housing body (2). The vacuum switch device (1) also has a spring support (6) on which a spring element (7) is supported, and which presses the moving electrical contact (4) in the direction of the stationary electrical contact (3). The invention also relates to a circuit (100) comprising a main current path (30) and a parallel auxiliary current path (40), wherein a vacuum switch device (1) is arranged in the auxiliary current path (40).