Segmented Reactor Mold Core for Gap-Free Leg-Yoke Alignment
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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, ensuring leg portion connecting surfaces are aligned on the same plane, reducing gaps and enhancing magnetic circuit integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If soft magnetic powder is compacted and annealed to form dust cores, then the core achieves necessary magnetic properties and structural integrity, but shrinkage and warpage occur during annealing causing uneven surfaces and gaps between leg and yoke portions
Solution Approach 1:
The yoke core is divided into multiple separate yoke portions (first yoke portion, second yoke portion, etc.) that are manufactured independently through compacting and annealing. This segmentation allows each portion to be processed separately, reducing the overall shrinkage and warpage effects compared to a single large component. The separate portions are then assembled using bonding or resin coating to form the complete yoke core structure.
2Volume of stationary object
If the size of the dust core is increased to meet reactor design requirements, then the core can handle higher magnetic flux, but the variation in shrinkage and warpage increases leading to larger gaps and higher magnetic resistance
Solution Approach 1:
Large yoke cores are divided into multiple smaller yoke portions that are individually manufactured with controlled shrinkage and warpage. This segmentation approach allows each smaller portion to maintain better dimensional stability during annealing, reducing the variation in gaps when assembled into the complete core structure.
Solution Approach 2:
Multiple separate yoke portions are combined through bonding or resin coating to form a complete large-sized yoke core. This merging process allows for compensation of individual portion variations, ensuring that the final assembled core maintains acceptable gap tolerances and magnetic circuit integrity despite the large overall size.
3Ease of manufacture
If gaps are formed between leg portions and yoke portions due to shrinkage and warpage, then the assembly is easier to manufacture, but magnetic resistance increases and DC superimposition characteristics deteriorate
Solution Approach 1:
The yoke portions are pre-coated with resin or pre-bonded before final assembly with the leg portions. This preliminary action ensures that when the components are brought together, the adhesive or resin fills any potential gaps, maintaining close contact between surfaces and minimizing magnetic resistance while still allowing for the natural shrinkage and warpage that occurs during manufacturing.
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 method effectively prevents gaps between leg and yoke portions, maintaining magnetic resistance within design specifications and improving the DC superimposition characteristics of inductance.
Implementation Method 1
The coil generates magnetic flux according to the number of turns by energization
Implementation Method 2
The core forms a closed magnetic circuit through which the magnetic flux generated by the coil passes according to a magnetic permeability higher than that of a vacuum
Implementation Method 3
The soft magnetic powder is compacted according to a shape of each leg portions and yoke portions
Implementation Method 4
The soft magnetic powder is compacted according to a shape of each leg portions and yoke portions, and then annealed
Data Source
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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.