PCB Coil Positioning Structure for Accurate Current Sensing
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Solution Overview
Problem
Current sensing devices with multiple coil elements face challenges in precise and economical positioning on substrates, particularly on simple substrates like PCBs, due to limited positioning precision and lack of compact, precise fixing methods.
Innovation Solution
A current sensing device with a substrate featuring circular holes and locating pins with bent sections that engage with flanges to create obtuse angles, ensuring accurate and secure positioning of coil elements, allowing for consistent signal measurement and improved immunity to external magnetic fields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If basic component placement concepts are used to mount coil elements on a PCB, then the device complexity is reduced, but the positioning precision deteriorates
Solution Approach 1:
The mounting structure is segmented into multiple functional components: locating pins for precise positioning, flanges for mechanical support, and connection terminals for electrical connection. This segmentation allows each component to perform its specific function optimally while maintaining overall simplicity
Solution Approach 2:
Locating pins act as intermediary elements between the PCB and coil element flanges. These pins provide a simple yet effective mechanism to achieve high positioning precision without complex mounting structures, bridging the gap between simple PCB fabrication and precise coil element placement
2Reliability
If significant clearance is provided between connecting pin and PCB hole, then the reliability of electrical connection is improved, but the positioning precision deteriorates
Solution Approach 1:
The connection system is divided into two independent functional segments: locating pins for positioning and connection terminals for electrical connection. This separation allows the locating pins to provide precise positioning with minimal clearance while connection terminals maintain adequate clearance for reliable electrical connection
Solution Approach 2:
Locating pins serve as intermediary positioning elements that are distinct from the electrical connection terminals. This intermediary structure enables precise coil element positioning without compromising the reliability of electrical connections, as each function is handled by dedicated components
3Strength
If fasteners like screws are used to firmly fix coil to substrate, then the mechanical strength is improved, but the device complexity and size increase
Solution Approach 1:
The complex screw and fastener mechanisms are extracted and replaced with simple locating pins that integrate directly into the PCB. This extraction eliminates unnecessary complexity while maintaining adequate mechanical strength through the pin-flange connection geometry
Solution Approach 2:
The locating pins and flange structure are designed to self-align and self-lock through their geometric configuration. The obtuse angle design of the pin creates natural mechanical interference that provides firm fixation without requiring additional fasteners or complex assembly procedures
4Manufacturing precision
If locating pins with bent sections are used to engage with flanges, then the positioning precision is improved, but the manufacturing complexity increases
Solution Approach 1:
The bent section of the locating pin is pre-formed during the pin manufacturing process rather than being bent during assembly. This preliminary action simplifies the assembly process while ensuring consistent positioning precision, as the bend geometry is controlled during manufacturing when tolerances can be better maintained
Data Source
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Figure 2B
AI summary
The present invention relates to a current sensing device, comprising: a substrate (40); and one or more coil elements (30). The substrate comprises a plurality of holes (100) projecting at least partway through the substrate from a first surface of the substrate, wherein prior to a coil element being mounted to the substrate each of the plurality holes has a circular cross section. The coil element comprises: a winding body (10, 20); two flanges (50) located at either end of the winding body; a length of wire (80); and two locating pins (60). The winding body has an outer surface around an axis of the winding body, and wherein at least a portion of the length of wire is wound multiple times around the outer surface of the winding body in a generally circumferential direction with respect to the axis of the winding body. When the coil element is mounted to the first surface of the substrate: - a first locating pin of the two locating pins is engaged in at least one locating cavity (130, 140, 250, 260) of a first flange of the two flanges and an end portion of the first locating pin of the two locating pins is located in a first hole of the plurality of holes, and a second locating pin of the two locating pins is engaged in at least one locating cavity (130, 140, 250, 260) of a second flange of the two flanges and an end portion of the second locating pin is located in a second hole of the plurality of holes; and - a first section (170) of the first locating pin including the end portion located in the first hole is bent with respect to a second section of the first locating pin such that there is an obtuse angle between the first section and second section of the first locating pin; and - a first section (170) of the second locating pin including the end portion located in the second hole is bent with respect to a second section of the second locating pin such that there is an obtuse angle between the first section and second section of the second locating pin.