Inductive Element Bobbin-Free Core Winding
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Solution Overview
Problem
Existing inductive elements, such as high power inductors and chokes, face issues with suboptimal copper fill factor, thermal resistance, and complex manufacturing due to the use of bobbins, which introduce air gaps and increase assembly difficulties.
Innovation Solution
The design eliminates the need for bobbins by winding electrical conductors directly onto magnetically permeable core-parts with optimized contact elements, allowing for modular assembly and improved thermal contact, thus enhancing copper fill factor and reducing thermal resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bobbins are used to carry windings and isolate them from the permeable core, then the windings are supported and isolated, but the copper fill factor is reduced and thermal resistance increases
Solution Approach 1:
The patent removes the bobbin component entirely from the inductive element structure. The windings are placed directly on the permeable core without any intermediate supporting structure, thereby eliminating the thermal barrier that bobbins create and improving thermal contact between the windings and core.
Solution Approach 2:
The patent merges the functions of support and magnetic flux path into a single component - the permeable core itself. By integrating the winding support function directly into the core structure, the design eliminates the need for separate bobbin components and improves thermal conductivity while maintaining structural support.
2Ease of manufacture
If bobbins are used with large tolerances to avoid assembly difficulties, then assembly is easier, but vibrations of the coils occur and copper fill factor is reduced
Solution Approach 1:
By removing the bobbin component, the patent eliminates the source of vibrations that occur with loose coil assemblies. The direct placement of windings on the core provides inherent mechanical stability without requiring tight-tolerance bobbins, thus avoiding vibration issues while maintaining ease of assembly.
3Reliability
If the winding window is introduced by the bobbin, then the windings are supported, but the copper fill factor becomes less than ideal
Solution Approach 1:
The patent eliminates the bobbin structure that creates the winding window, allowing the windings to be placed directly on the core. This removal of the intermediate supporting structure enables the windings to be positioned closer to the core surface, maximizing the copper fill factor while maintaining adequate support.
4Reliability
If U-shaped core-parts are arranged adjacent to each other with air gaps inside the bobbins, then the magnetic flux path is formed, but the thermal contact between core and winding is reduced
Solution Approach 1:
The patent combines the magnetic flux path function and thermal conduction function into the same direct contact interface between windings and core. By placing windings directly on the core surface, the design ensures both magnetic coupling and thermal contact occur through the same intimate interface, eliminating the thermal barrier created by bobbins.
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
This approach results in a more efficient inductive element with improved thermal dissipation and simplified manufacturing, enabling flexible core-part arrangements and efficient heat transfer without the need for additional supporting structures.
Implementation Method 1
Each core-part has a centre piece with opposite ends defining a longitudinal axis of the core-part with respect to which the centre piece has an outer surface
Implementation Method 2
The inductive element comprises a winding of an electrical conductor
Implementation Method 3
the contact surface of each contact element abuts on a lateral contact surface of another core-part
Data Source
Figure 1a~2
Figure 3
Figure 4
AI summary
An inductive element comprises at least two core-parts including a magnetically permeable material and at least one winding of an electrical conductor which can be a foil winding, a stranded wire (litz) winding or a conventional wire winding. Each core-part has an elongated centre piece with an outer winding surface. At each of its longitudinal ends, the centre piece has contact elements with a lateral contact surfaces. According to the invention, the winding is wound directly on the core-parts without a bobbin or the-like. The core-parts of the inductive element are arranged with their longitudinal axes essentially in parallel in a manner that the lateral contact surfaces of each contact element abut on a lateral contact surface of another core-part. According to the invention, such an inductive element can be manufactured by co-axially arranging the core-parts and using them as a roll-shaft. After the windings have been applied to the core-parts, they can be rearranged, i.e. "flipped over", in a stack-like arrangement in order to form an inductive element according to the invention. Further, the invention relates to a core-part for an inductive element.