Coil-embedded magnetic core and coil device
A coil-embedded magnetic core capable of achieving improvements both in insulation and initial magnetic permeability, and coil devices thereof. The coil-embedded magnetic core embedding a coil made of a conductor, including magnetic powder and a resin, in which the coil-embedded magnetic core further includes a modifier.
1 . A coil-embedded magnetic core embedding a coil made of a conductor, comprising magnetic powder and a resin, wherein
the coil-embedded magnetic core further comprises a modifier,
the modifier comprises a polycaprolactone structure,
a content of the magnetic powder in the coil-embedded magnetic core is preferably 90 to 99 wt %, and
a content of the modifier is 0.3 to 0.8 wt %,
the wt % s being with respect to a total amount of the coil-embedded magnetic core.
2 . The coil-embedded magnetic core described in claim 1 , wherein
a content of the modifier is 0.3 to 0.6 wt % with respect to a total amount of the coil-embedded magnetic core.
3 . The coil-embedded magnetic core described in claim 1 , wherein
the magnetic powder comprises a soft magnetic metal.
4 . The coil-embedded magnetic core described in claim 3 , wherein
the magnetic powder is a part of insulation coated particles, and each of the insulation coated particles contain a soft magnetic powder of the soft magnetic metal coated with an insulation coating including SiO 2 .
5 . The coil-embedded magnetic core described in claim 1 , wherein
the magnetic powder includes at least two kinds of magnetic powders comprising a small-diameter powder and a large-diameter powder mutually having different particle sizes.
6 . The coil-embedded magnetic core described in claim 5 , wherein
D90 of the small-diameter powder is 4.0 μm or less, and
the small-diameter powder is coated.
7 . The coil-embedded magnetic core described in claim 5 , wherein
a composition of the small-diameter powder comprises Fe—Ni.
8 . The coil-embedded magnetic core described in claim 5 , wherein
a blending ratio of the small-diameter powder with respect to the total magnetic powder is 6.5 to 20 wt %.
9 . The coil-embedded magnetic core described in claim 5 , wherein
the thickness of the insulating coating of the large-diameter powders of magnetic powder is thicker than the insulating coating of the small-diameter powder of the magnetic powder.
10 . The coil-embedded magnetic core described in claim 5 , further having a medium diameter powder lager in particle size than the small-diameter powder and smaller than the large-diameter powder.
11 . The coil-embedded magnetic core described in claim 1 , wherein
a content of the modifier is 0.4 to 0.6 wt % with respect to a total amount of the coil-embedded magnetic core.
12 . A coil device comprising:
a coil made of a conductor;
a coil-embedded magnetic core embedding the coil, comprising magnetic powder and a resin; and
a pair of external terminals electrically connected to the coil, wherein
the coil-embedded magnetic core comprises a modifier,
the modifier comprises a polycaprolactone structure,
a content of the magnetic powder in the coil-embedded magnetic core is preferably 90 to 99 wt %, and
a content of the modifier is 0.3 to 0.8 wt %,
the wt % s being with respect to a total amount of the coil-embedded magnetic core.