| 摘要 |
PROBLEM TO BE SOLVED: To solve a problem wherein, when a conventional dust core is compared with a core made of a laminated steel plate, the conventional dust core is particularly large in eddy current loss, and has a disadvantage when used in a high-frequency range or a high rotation speed range as a motor or the like. SOLUTION: In this dust core 11 containing at least one green compact 13, the green compact 13 includes: a pair of surface parts 13a extending parallel to each other in a direction orthogonal to electromotive force F generated in a direction for hindering the change of magnetic flux B permeating the dust core 11; and a region located at the middle between the pair of surface parts 13a and having low density relative to that of the surface parts 13a, that is, a neutral zone 13b. The dust core 11 includes two or more green compacts 13, and can form an electric insulation layer 14 as an adhesive between the surface parts 13a of the green compacts 13 overlapping each other. It is preferable that the specific resistance value of the neutral zone 13b of the green compact 13 is three or more times the specific resistance value of the surface part 13a thereof. COPYRIGHT: (C)2011,JPO&INPIT
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