Ceramic Reed Switch Structure for Stable Contacts at High Current
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Solution Overview
Problem
Conventional glass reed switches face issues with high-temperature demagnetization, unreliable contacts, and mechanical reliability due to soft magnetic reeds and pins made of iron and nickel, leading to inconsistent performance and increased risk of air leakage when handling large-load currents or high-frequency signals.
Innovation Solution
A ceramic reed switch design featuring a ceramic tube with cantilever magnetic reeds and non-magnetic oxygen-free copper pins, eliminating the need for glass and allowing for higher Curie temperature and conductivity materials, which enhances magnetic performance and mechanical strength while reducing bending stress and air leakage risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soft magnetic reeds and iron-nickel pins are used in conventional glass reed switches, then magnetic control functionality is achieved, but high-temperature demagnetization and unreliable contacts occur when handling large-load currents
Solution Approach 1:
The patent changes the material parameters by replacing soft magnetic reeds with permanent magnets and iron-nickel pins with non-magnetic oxygen-free copper pins. This parameter change enables the reed switch to handle large-load currents without high-temperature demagnetization, as permanent magnets maintain their magnetic properties at higher temperatures and copper has superior thermal and electrical conductivity.
Solution Approach 2:
The patent employs composite material construction by combining permanent magnets with non-magnetic oxygen-free copper pins and ceramic tubes. This composite structure integrates the advantages of each material: permanent magnets provide stable magnetic fields, copper provides excellent electrical and thermal conductivity without magnetic interference, and ceramic provides high-temperature resistance and mechanical strength.
2Manufacturing precision
If iron and nickel alloy pins are used in glass reed switches, then magnetic circuit functionality is achieved, but pin cutting or bending causes changes in AT value and driving parameters
Solution Approach 1:
The patent extracts the magnetic function from the pin by using non-magnetic oxygen-free copper pins instead of magnetic alloy pins. The pins no longer participate in the magnetic circuit, eliminating the problem where pin bending or cutting changes the AT value. The magnetic field generation is instead achieved through permanent magnets, which are not susceptible to mechanical deformation affecting magnetic properties.
Solution Approach 2:
The patent applies local quality by assigning different functional properties to different components: permanent magnets provide magnetic fields, non-magnetic copper pins provide electrical connections without magnetic interference, and ceramic tubes provide structural support. This functional separation ensures that mechanical stress on pins does not affect magnetic circuit parameters.
3Power
If large-diameter glass reed switches are used for large-load applications, then current handling capacity is increased, but glass tube breaking or air leakage at sealed parts occurs
Solution Approach 1:
The patent replaces the glass tube with a ceramic tube, creating a composite structure that maintains the sealed chamber functionality while providing superior mechanical strength and fracture resistance. Ceramic materials have higher tensile strength and are less prone to sudden catastrophic failure compared to glass, enabling large-diameter switches to handle higher currents without breaking or leaking.
Solution Approach 2:
The patent employs a cylindrical ceramic tube structure with optimized curvature and thickness distribution. The circular cross-section and smooth curvature of the ceramic tube distribute mechanical stresses evenly, preventing stress concentration that could lead to cracking or breaking under large-load conditions.
4Force
If soft magnetic reeds with high resistivity are used in reed switches, then magnetic control is achieved, but current heating causes high-temperature demagnetization of the magnetic circuit
Solution Approach 1:
The patent replaces the soft magnetic reed system with a permanent magnet system. Instead of relying on current-induced magnetization in high-resistivity soft magnetic reeds, the system uses permanent magnets that generate magnetic fields independently of current flow. This substitution eliminates the heating problem associated with high-resistivity materials, as the permanent magnets do not require high current densities to maintain their magnetic fields.
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 ceramic reed switch improves contact reliability, reduces the risk of air leakage, and ensures consistent performance by using non-magnetic copper pins and higher Curie temperature materials, addressing the limitations of conventional glass reed switches.
Implementation Method 1
Under the action of an external magnetic field in a left-right direction, magnetic flux flows through the first magnetic reed and the second magnetic reed so that the first magnetic reed and the second magnetic reed attract each other at the air gap
Implementation Method 2
the first magnetic reed and the second magnetic reed attract each other at the air gap and are finally closed to cause a circuit to be connected
Implementation Method 3
after the external magnetic field disappears, the first magnetic reed and the second magnetic reed cause the contact to be separated and restored to an initial state under the action of elastic restoring forces of the first magnetic reed and the second magnetic reed
Data Source
AI summary
A ceramic reed switch includes a ceramic tube, and a first end cover and a second end cover, a first pin is disposed on an outer side of the first end cover, a first magnetic reed is disposed on an inner side of the first end cover, the first magnetic reed forms a cantilever beam structure on the first end cover, a second pin is disposed on an outer side of the second end cover, a second magnetic reed is disposed on an inner side of the second end cover, the second magnetic reed forms a cantilever beam structure on the second end cover, free ends of the first magnetic reed and the second magnetic reed are overlapped in the ceramic tube and form an air gap, and a contact is disposed on an overlapped end of the first magnetic reed and the second magnetic reed.