Segmented Mold Core Structure to Eliminate Reactor Leg-Yoke Gaps
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Solution Overview
Problem
The shrinkage and warpage of soft magnetic powder cores during annealing lead to uneven surfaces and gaps between leg and yoke portions, increasing magnetic resistance and deteriorating DC superimposition characteristics in reactors.
Innovation Solution
A mold core manufacturing method involving insert molding of yoke cores into multiple core blocks with aligned leg portion connecting surfaces, using resin to cover and connect leg portions without gaps, ensuring precise alignment and reducing deformation variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the size of the dust core increases, then the reactor can handle higher power requirements, but the variation in shrinkage and warpage in various parts of the dust core increases
Solution Approach 1:
The yoke core is divided into multiple core blocks (first core block, second core block, third core block) that are connected in a row without gaps. Each core block contains leg portion connecting surfaces that are aligned on the same plane. This segmentation allows each block to be manufactured with controlled shrinkage and warpage, while the overall structure maintains precision through the aligned connecting surfaces.
2Length of moving object
If the yoke portions become large, then the reactor can accommodate larger leg portions for higher current, but the unevenness on the surface where leg portion connecting surfaces are lined becomes noticeable due to shrinkage and warpage
Solution Approach 1:
The yoke core is segmented into multiple core blocks, each containing leg portion connecting surfaces. By dividing the large yoke portion into smaller manageable blocks, the shrinkage and warpage in each block can be controlled, and the leg portion connecting surfaces can be aligned on the same plane, reducing surface unevenness.
Solution Approach 2:
The leg portion connecting surfaces in each core block are specifically designed to be aligned on the same plane. This local precision in the connecting surfaces ensures that when leg portions are butted against these surfaces, gaps are minimized, maintaining magnetic circuit integrity even in large-scale reactors.
3Ease of manufacture
If gaps are generated between the end face of leg portions and the leg portion connecting surfaces, then the assembly is easier to manufacture, but the magnetic resistance increases and DC superimposition characteristic deteriorates
Solution Approach 1:
The leg portion connecting surfaces in each core block are aligned on the same plane, creating a uniform surface level. This equipotential alignment ensures that when leg portions are assembled against these surfaces, the contact is uniform and gaps are minimized, maintaining low magnetic resistance while simplifying the assembly process.
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 method ensures that leg portion connecting surfaces are aligned on the same plane, minimizing gaps and maintaining designed magnetic resistance, thereby improving the DC superimposition characteristics of inductance in reactors.
Implementation Method 1
yoke resin molding the yoke core by insert molding
Implementation Method 2
The soft magnetic powder is compacted according to a shape of each leg portions and yoke portions
Implementation Method 3
The soft magnetic powder is compacted according to a shape of each leg portions and yoke portions, and then annealed
Data Source
AI summary
Provided is a mold core, a reactor having the mold core, and a manufacturing method of the mold core in which the leg portion connecting surfaces of the yoke portions are aligned at the same height and gaps are prevented from forming between the end surfaces of the leg portions and the leg portion connecting surfaces. The mold core 2 of the reactor 1 is made of a dust core and includes the yoke cores 41 for connecting a plurality of leg portions 32, and the yoke resins 42 for molding the yoke cores 41 by insert molding. The yoke cores 41 are divided into a plurality of core blocks 5 connected in a row without gaps, and the core blocks 5 include leg-portion-side blocks 61 that are connected to the leg portions 32 one-to-one.