Inductor Core Protrusion for Single-Step Pressing
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Solution Overview
Problem
The manufacturing of inductor cores with recesses and slits is complex and costly due to the need for additional machining processes or specialized presses, which can lead to density variations and increased risk of fissuring under high pressing forces.
Innovation Solution
The design incorporates a first protrusion on the base core portion to compensate for the volume lost in forming a recess, allowing for a single pressing operation without additional machining, using a simple press and minimizing punch bias, thus achieving uniform material density and reduced risk of fissuring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a recess and slit are formed in the inductor core to accommodate winding connections, then the winding fill factor is improved, but the manufacturing complexity increases requiring additional machining processes
Solution Approach 1:
The protrusion is formed on the punch during the pressing operation itself, rather than adding it after pressing. This preliminary action allows the protrusion to be created as part of the base core portion formation, enabling subsequent recess and slit formation without requiring separate machining operations.
Solution Approach 2:
The base core portion is segmented into different regions: a first region with the recess for accommodating winding connections and a second region with the protrusion for maintaining structural integrity. This segmentation allows each region to serve its specific function while being manufactured in a single pressing operation.
2Manufacturing precision
If pressing force is increased to achieve high density, then magnetic saturation is improved, but the risk of punch bias and fissuring increases
Solution Approach 1:
The protrusion acts as a counterbalancing feature that compensates for the stress concentration caused by the recess. By adding material in the protrusion region, the overall stress distribution during pressing is balanced, preventing punch bias and reducing the risk of fissuring while allowing high pressing forces to achieve the desired density.
Solution Approach 2:
The base core portion has different local properties: the first region with the recess has reduced material to accommodate connections, while the second region with the protrusion has increased material to maintain structural integrity and distribute stress. This local quality variation allows high density in connection areas without compromising overall reliability.
3Manufacturing precision
If additional machining processes are used to form recess and slit, then manufacturing precision is improved, but manufacturing time and cost increase
Solution Approach 1:
The formation of the base core portion, recess, and slit is merged into a single pressing operation. The protrusion formed on the punch during pressing enables the recess and slit to be created simultaneously with the base core portion, eliminating the need for separate machining operations and significantly reducing manufacturing time.
Solution Approach 2:
The pressing operation is made multi-functional by designing the punch with an integrated protrusion that simultaneously forms the base core portion and enables the recess and slit. This universal approach allows a single tool to perform multiple functions that would otherwise require separate machining processes.
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 enables the cost-effective and efficient manufacture of inductor cores with recesses and slits in a single operation, maintaining high material density and reducing manufacturing time and tooling complexity.
Implementation Method 1
The powder may be put into a cavity wherein the powder may be compacted. In some cases it may be desirable to compress the soft magnetic material powder to a high density
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3~4
AI summary
According to the present inventive concept there is provided an inductor core made of a compressed soft magnetic powder material. The inductor core comprises: a base core portion having a first surface and an opposite second surface; an inner core portion extending from the first surface in a direction transverse to the first surface; an outer core portion extending, in the direction transverse to the first surface, from the first surface to an end surface of the outer core portion, the outer core portion at least partly surrounding the inner core portion, thereby forming a space around the inner core portion for accommodating a winding; wherein the first surface comprises a recess for accommodating a connection portion of the winding, said recess extending at least a part of a distance between the inner core portion and the outer core portion, and wherein the outer core portion presents a slit extending from said end surface towards the recess, and wherein the second surface comprises a first protrusion oppositely arranged to the recess. There is also provided an arrangement for a press and a manufacturing method.