Sealed Contact Device Arc Heat Shielding
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Solution Overview
Problem
Existing sealed contact devices experience degradation in sealing performance due to the exposure of brazed portions to arc-generated heat, which compromises the integrity of the sealed space.
Innovation Solution
The integration of an annular rib on the annular flange covers the brazed portion between the ceramic case and the flange, preventing heat from the arc from reaching the brazed area, while an annular groove enhances alignment and support, and a cylindrical insulating member prevents electrical welding between iron cores and the movable shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the brazed portion is exposed in the sealed space, then the assembly is simple, but the sealing performance degrades when arc is generated
Solution Approach 1:
An annular rib is introduced as an intermediary protective structure between the arc generation zone and the brazed portion. The rib extends from the inner peripheral surface of the annular flange toward the ceramic case, creating a physical barrier that shields the brazed joint from arc heat while maintaining the overall assembly simplicity
Solution Approach 2:
The solution transitions from a two-dimensional exposed brazed joint to a three-dimensional protected structure by adding the annular rib that protrudes into the sealed space. This dimensional addition creates a protective shield without significantly increasing assembly complexity
2Reliability
If the brazed portion is covered by the annular rib, then the sealing performance is maintained, but the device complexity increases
Solution Approach 1:
The annular rib is merged with the annular flange as an integrated structure rather than a separate component. The rib is formed as part of the flange itself, combining the protective function with the existing structural element and avoiding additional assembly steps
Solution Approach 2:
The annular flange serves multiple functions: it provides structural support, facilitates brazing to the ceramic case, and incorporates the annular rib for arc protection. This multi-functionality reduces the need for additional separate protective components
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 configuration maintains high sealing performance, assembly accuracy, and reliability by isolating the brazed area from arc heat and preventing electrical welding, thus ensuring the device's structural integrity and operational stability.
Implementation Method 1
a movable shaft whose the other end is fixed to a movable iron core reciprocating in the closed-ended cylinder based on excitation and demagnetization of an electromagnetic unit
Implementation Method 2
a lower end surface of a ceramic case is brazed to an upper surface of an annular flange
Implementation Method 3
whose outer peripheral edge portion is integrally welded to an upper surface of the plate-like yoke
Data Source
Figure 1
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Figure 3
AI summary
An aspect of the invention provides a sealed contact device in which sealing performance is not degraded even if arc is generated. In the sealed contact device, an opening edge portion of a closed-ended cylinder (41) is integrated with lawer-surface edge portion of a center hole (35a) made in a plate-like yoke (35) to form a sealed space while a lower end surface of a ceramic case (31) is brazed to an upper surface of an annular flange (34) whose outer peripheral edge portion is integrally welded to an upper surface of the plate-like yoke (35). A movable contact (48a) of a movable touch piece (48) fixed to one end portion of a movable shaft (45) is brought into contact with and separated from a fixed contact (32a) disposed in the ceramic case (31) by reciprocating the movable shaft (45) whose the other end is fixed to a movable iron core (40) reciprocating in the closed-ended cylinder (41) based on excitation and demagnetization of an electromagnetic unit (50) disposed in an outer periphery of the closed-ended cylinder (41). Particularly, an annular rib (34c) is projected in the upper surface of the annular flange (34) such that the brazed portion provided in the lower end surface of the ceramic case (31) is covered from an inside with the annular rib (34c).