US 11,990,271 B2
Soft magnetic ribbon for magnetic core, magnetic core, coil unit, and wireless power transmission unit
Isao Nakahata, Tokyo (JP); and Mitsuhiro Matsuhashi, Tokyo (JP)
Assigned to TDK CORPORATION, Tokyo (JP)
Filed by TDK CORPORATION, Tokyo (JP)
Filed on Mar. 19, 2018, as Appl. No. 15/924,847.
Claims priority of application No. 2017-063161 (JP), filed on Mar. 28, 2017; and application No. 2018-005105 (JP), filed on Jan. 16, 2018.
Prior Publication US 2018/0286550 A1, Oct. 4, 2018
Int. Cl. H01F 3/04 (2006.01); H01F 1/14 (2006.01); H01F 3/10 (2006.01); H01F 27/25 (2006.01); H01F 38/14 (2006.01); H01F 41/02 (2006.01); H02J 50/10 (2016.01)
CPC H01F 3/04 (2013.01) [H01F 1/14 (2013.01); H01F 3/10 (2013.01); H01F 27/25 (2013.01); H01F 38/14 (2013.01); H01F 41/0226 (2013.01); H02J 50/10 (2016.02); H01F 41/0213 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A soft magnetic ribbon for a magnetic core, the soft magnetic ribbon comprising one surface perpendicular to a thickness direction of the soft magnetic ribbon, wherein
the soft magnetic ribbon is made of a plurality of pieces made of a magnetic alloy,
the plurality of pieces are physically segmented and each of the pieces is separated by cracks therebetween,
the one surface is made of a first region, a second region and a third region,
the first region has a circular or tetragonal shape,
an inside and an outside of the first region are made of the second region and the third region,
the third region is in the vicinity of a boundary between the first region and the second region,
an average crack interval in the first region is 25 to 114 times larger than an average crack interval in the second region,
an average crack interval in the third region is smaller than the average crack interval in the second region,
the average crack interval in the first region being a length of a line drawn in the first region divided by a number of cracks intersecting the line in the first region,
the average crack interval in the second region being a length of a line drawn in the second region divided by a number of cracks intersecting the line in the second region,
the average crack interval in the third region being a length of a line drawn in the third region divided by a number of cracks intersecting the line in the third region, and
the third region is a region which is an inner peripheral edge and an outer peripheral edge of the first region, and a width of the inner peripheral edge and the outer peripheral edge is 10% or less of an outer diameter of the first region.