Miniature Switching Device with Rotating Magnet and Flex Circuit
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Solution Overview
Problem
Existing miniature switching devices often require complex and costly high-technology PCBs and multiple magnets, which increase production costs and complexity, while also facing challenges in achieving reliable and efficient contact switching.
Innovation Solution
A miniature switching device design utilizing a single small permanent magnet and a flex printed circuit with a soft iron core coil, where the magnet rotates about a pivot point to open or close electrical contacts, leveraging a multilayer PCB and plastic spacers for cost-effective manufacturing and reliable contact switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple magnets and complex high-technology PCBs are used in miniature switching devices, then magnetic actuation reliability is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The patent combines multiple magnets into a single permanent magnet that works in conjunction with a soft iron core coil. This merging reduces the number of magnetic components from multiple separate magnets to one integrated magnet-coil assembly, simplifying the device structure while maintaining reliable magnetic actuation for contact switching
Solution Approach 2:
The soft iron core coil serves multiple functions: it generates magnetic field when energized, works as a magnetic circuit element with the permanent magnet, and provides structural support for the contact assembly. This multi-functionality reduces the need for separate dedicated components, lowering device complexity
2Reliability
If multiple magnets and high-technology PCBs are used, then switching reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive high-technology PCBs with standard printed circuit board technology that is widely available and cost-effective. The simplified magnetic assembly using one permanent magnet and a soft iron core coil also reduces component costs compared to multiple precision-machined magnetic components, making the device more manufacturable at scale
Solution Approach 2:
The invention changes the magnetic circuit parameters by using a soft iron core with high permeability to concentrate and guide magnetic flux efficiently. This allows reliable actuation with fewer and smaller magnetic components, reducing both material costs and manufacturing complexity while maintaining switching reliability
3Device complexity
If a single permanent magnet with soft iron core coil is used, then manufacturing cost and device complexity are reduced, but magnetic actuation force must be optimized
Solution Approach 1:
The soft iron core is designed with specific local geometries including pole pieces and flux concentrating features that optimize magnetic field distribution. The permanent magnet is positioned and dimensioned to create concentrated magnetic flux paths at the contact switching points, ensuring sufficient actuation force is generated locally where needed despite using only one magnet
Solution Approach 2:
The soft iron core acts as a magnetic intermediary that amplifies and directs the magnetic field from the permanent magnet. When current flows through the coil, it modifies the magnetic circuit through the soft iron core, creating strong localized magnetic forces that actuate the contacts. The soft iron core mediates between the permanent magnet and the air gap, concentrating flux to generate adequate force
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 achieves reliable and efficient contact switching with a lower-cost, mainstream PCB technology, enabling higher volume manufacturing and reducing production costs while maintaining the reliability of contact connections.
Implementation Method 1
when a power pulse is applied to the coil, one end of the coil will be north and the other end will be south
Implementation Method 2
The permanent magnet is thereafter attracted to the soft iron core inside the coil, which holds the permanent magnet in place after the power pulse terminates
Data Source
Figure 1~2
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AI summary
A permanent magnet is pivotally mounted in a top spacer layer of a switching device and rests on a flex arm created in an underlying flex circuit layer. The underside of the flex arm rests on a thin bar formed in a lower spacer layer beneath which lies a base layer including an electromagnet. Activation of the electromagnet causes rotation of the flex arm to thereby close and open electrical contacts formed respectively on the underside of the flex arm and on the top surface of the base layer.