Coil Device Partitioned Core for Axial Length Reduction
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Solution Overview
Problem
Existing coil devices with crossed winding parts face challenges in downsizing due to increased axial length, which affects inductor characteristics, and non-magnetic material cores may not meet the required characteristics for DC-DC converters.
Innovation Solution
A coil device design featuring a core with a columnar shaft, first and second winding parts, and a partition portion on the outer peripheral surface that divides the winding parts, allowing for reduced magnetic coupling and axial length, while maintaining magnetic characteristics through close positioning of winding parts and core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two winding parts are crossed each other in each turn to weaken magnetic coupling, then magnetic coupling is weakened and inductance characteristics are stabilized, but the axial length of the core increases and downsizing becomes difficult
Solution Approach 1:
The core is segmented by introducing a partition portion that divides the winding parts in the radial direction. This segmentation allows the winding parts to be arranged side-by-side rather than crossed, reducing the axial length while maintaining the magnetic coupling weakening effect through spatial separation.
Solution Approach 2:
The arrangement of winding parts is changed from axial crossing (one-dimensional arrangement along the axis) to radial side-by-side arrangement (utilizing the radial dimension). This dimensional change allows the winding parts to be positioned adjacent to each other in the radial direction, reducing the axial length while still achieving magnetic coupling reduction through the partition portion.
2Reliability
If non-magnetic material core is used with crossed winding parts, then magnetic coupling is weakened, but the core cannot satisfy characteristics required for DC-DC converter applications
Solution Approach 1:
The core is segmented by introducing a partition portion that divides the winding parts in the radial direction. This segmentation allows the winding parts to be arranged side-by-side rather than crossed, reducing the axial length while maintaining the magnetic coupling weakening effect through spatial separation.
Solution Approach 2:
The core material is changed from non-magnetic to magnetic material, changing the magnetic properties parameter. Combined with the partition portion structure, this allows the use of magnetic cores that satisfy DC-DC converter requirements while still achieving magnetic coupling reduction through the partition structure rather than relying on non-magnetic material properties.
3Reliability
If partition portion protrudes far from outer peripheral surface to divide winding parts, then magnetic coupling is weakened, but the projected area in axial direction increases
Solution Approach 1:
The partition portion protrudes only partially from the outer peripheral surface of the core, just enough to divide the winding parts in the radial direction. This partial action is sufficient to achieve magnetic coupling reduction while minimizing the increase in projected area, avoiding excessive protrusion that would unnecessarily increase the axial footprint.
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 effectively weakens magnetic coupling, stabilizes inductance, and achieves downsizing by reducing the axial length and DC resistance, while preventing magnetic flux leakage and improving magnetic characteristics.
Implementation Method 1
a magnetic coupling between one winding part and the other winding part may be desired to be weakened
Implementation Method 2
prevent interruption of magnetic loop flowing from the first flange to the second flange through the outside of the first winding part and the second winding part
Data Source
AI summary
A coil device includes a core (20) having a columnar shaft (22), a first winding part (42) and a second winding part (46) that are wound around the shaft, and a terminal part (52) connected with ends of the first winding part and ends of the second winding part. A partition portion (30) provided on an outer peripheral surface (22a) of the shaft of the core protrudes from the outer peripheral surface toward the outer diameter direction and divides a part of the first winding part and a part of the second winding part.