Stacked Bobbin Filter-Choke Assembly for Reproducible EMI Coils
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Solution Overview
Problem
Existing filter-choke production methods for EMI filters are labor-intensive and lack reproducibility, especially when using wires with large cross sections, leading to inconsistent magnetic properties and increased component size.
Innovation Solution
A filter-choke design comprising a closed magnetic core assembled from multiple core segments and bobbins, allowing for automated production and enhanced reproducibility, with coils pre-wound on bobbins and a low reluctance bypass path to minimize magnetic reluctance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If manual winding process is used for producing coils around the magnetic core, then flexibility in handling large cross-section wires is improved, but labor intensity and production time increase significantly
Solution Approach 1:
The coil is pre-formed as a complete winding around the bobbin before assembly with the magnetic core. This preliminary action allows automated formation of the coil structure, eliminating manual winding operations during final assembly and significantly reducing labor intensity while maintaining the ability to handle large cross-section wires.
Solution Approach 2:
The bobbin serves as an intermediary component that holds the pre-formed coil in a structured manner. The bobbin with pre-formed coil can then be easily assembled with the magnetic core, bridging the gap between automated coil formation and final filter-choke assembly, thereby improving productivity without sacrificing operational flexibility.
2Adaptability or versatility
If manual production process is used, then adaptability to different wire types is improved, but manufacturing precision and reproducibility deteriorate
Solution Approach 1:
The coil is pre-formed with precise specifications before assembly. This preliminary formation process can be performed with high precision equipment, ensuring consistent winding parameters, tension, and geometry. The pre-formed coil is then assembled as a complete unit, guaranteeing reproducibility across multiple filter-choke productions while maintaining adaptability to different wire types through standardized pre-formation processes.
3Reliability
If closed magnetic core is designed as one-piece component, then magnetic reluctance is reduced, but assembly complexity and component size increase
Solution Approach 1:
The filter-choke is segmented into modular components: the magnetic core, the bobbin with pre-formed coil, and the housing. The magnetic core itself can be segmented into multiple parts that assemble to form the closed magnetic path. This segmentation allows each component to be manufactured and prepared separately with optimized designs, then assembled together, reducing overall assembly complexity and component size while maintaining the low magnetic reluctance of the closed core structure.
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
Enables cost-effective, highly reproducible production of filter-choke with improved magnetic properties and reduced size, suitable for applications requiring low ohmic resistance, such as power electronic devices.
Implementation Method 1
the magnetic core comprises a low magnetic reluctance
Implementation Method 2
the core is designed as a closed magnetic core in form of a one-piece component
Data Source
Figure 1a
Figure 1b
Figure 2
AI summary
The application discloses a filter-choke (10) to be used in an EMI filter comprising: - a closed magnetic core (20) having two core-legs (21, 22), wherein the magnetic core is configured to be assembled out of at least two core-segments (23), - at least two bobbins (30), each bobbin comprising a base flange (31) and a tubular section (32a, 32b) extending in perpendicular direction from the base flange (31), wherein the tubular section (32a, 32b) comprises an opening (33) for receiving one of the two core-legs (21, 22), - a coil (40) formed by an electric conductor (41) having multiple windings arranged around the tubular section (32a, 32b) of each bobbin (30), characterized, in that in an assembled state of the filter-choke (10), the bobbins (30) are arranged in a stacked manner, such that their openings (33) are aligned coaxially to each other, one of the core legs (21, 22) extending through the openings (33), and in that each bobbin (30) comprise at least two first fitting elements (35) arranged on opposite edges (34) of its base flange (31), wherein the first fitting elements (35) of the first bobbin (30) are configured to engage with the first fitting elements (35) of the adjacent second bobbin (30) for releasably fixing the two bobbins (30) together. The application further discloses a method for producing said filter-choke (10) as well as an electrical device comprising said filter-choke (10).