Segmented Toroidal Choke Coil for Dense High-Frequency Winding
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Solution Overview
Problem
Choke coils used in high-frequency circuits face challenges in achieving high occupancy ratios and efficient manufacturing due to difficulties in winding larger-diameter coated wires, leading to misalignment, collapse, and increased size, while Litz wire solutions require complex designs and are costly.
Innovation Solution
A toroidal-shaped choke coil design using a pair of arc-shaped core pieces with molded insulating coatings and solid coated wires wound in parallel layers, allowing for automatic winding and increased occupancy ratios without twisting, reducing size and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If larger-diameter coated wire is used to increase occupancy ratio, then DC resistance loss is reduced, but winding becomes difficult causing misalignment and collapse
Solution Approach 1:
The core is divided into two separate arc-shaped core pieces instead of using a complete toroidal core. This segmentation allows the coated wire to be wound from one end of the core piece to the other without needing to pass through a central hole, enabling easier manual or automated winding of larger-diameter wires while maintaining high occupancy ratios
Solution Approach 2:
Instead of winding the wire through the central hole of a toroidal core (conventional approach), the invention inverts the winding approach by starting at one end edge of the core piece and winding around the body to the other end edge, eliminating the need to pass through the central hole and enabling use of larger-diameter coated wire
2Reliability
If more turns are wound to achieve required characteristics, then inductance is improved, but the central hole must be smaller making winding harder
Solution Approach 1:
Dividing the core into two arc-shaped pieces eliminates the central hole constraint, allowing the wire to be wound along the outer perimeter of the core pieces. This enables achieving the required number of turns for proper inductance characteristics without being limited by a small central hole diameter
Solution Approach 2:
The winding path is changed from a radial direction through the central hole to a circumferential path around the core body. This dimensional change in the winding approach allows for more turns to be accommodated along the extended path of the core pieces without requiring a smaller central hole
3Manufacturing precision
If manual winding is performed to achieve required turns, then quality is maintained, but mass production becomes difficult
Solution Approach 1:
The segmented core structure with open ends enables automated winding machines to easily feed and wind the coated wire along the core pieces without complex manipulation required for toroidal cores with small central holes, thus maintaining quality while enabling mass production
Solution Approach 2:
The invention replaces manual winding operations with automated winding equipment. The simplified core structure with arc-shaped pieces and open ends is specifically designed to be compatible with automated winding machines, substituting manual labor with mechanical automation while maintaining winding quality
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 higher density winding, increased occupancy ratios, and stable manufacturing, resulting in smaller, high-performance choke coils suitable for high-frequency circuits with reduced copper loss and heat generation, and enabling efficient production using automatic equipment.
Implementation Method 1
Choke coils used in power supply circuits and high-frequency circuits of various AC devices are composed of a toroidal core covered with a molded insulating coating that is formed by a bobbin or a surface treatment, and have windings wound multiple turns with a coated wire (magnet wire)
Implementation Method 2
a molded insulating coating to cover the core segment and provide the core segment with an electrical insulation
Implementation Method 3
the second factor in the copper loss is epidermal effect phenomenon caused by high-frequency currents. As the frequency 'f' increases, the internal resistance of the copper wire increases and the current becomes more surface-tendentious
Data Source
AI summary
The present invention provides a choke coil suitable for high-frequency circuits with high occupancy ratio and high manufacturing efficiency.The present choke coil 10 comprises a pair of core pieces 20, 20, wherein each of the core pieces comprises an arc-shaped core segment 31 having end faces 32, 32a,a molded insulating coating 34 to cover the core segment and provide the core segment with an electrical insulation, the molded insulating coating having flanges 35, 35 extending outward from each of the end faces of the core segment, a coated wire 40 wound around the molded insulating coating, and terminals 50, 50 provided near the flange of the molded insulating coating and electrically connected to the coated wire, wherein the choke coil is a toroidal shape formed by placing the end faces of the arc-shaped core segment of one of the core pieces to face the end faces of the arc-shaped core segment of the other core piece, and the coated wire is wound around the circumference of the molded insulating coating in parallel without being twisted to each other and is electrically connected to the terminals.