公开(公告)号：US20140335268A1

公开(公告)日：2014-11-13

申请号：US14340957

申请日：2014-07-25

Applicant: TDK Corporation

Inventor： Satoshi Tanaka ,  Fumitaka Baba ,  Makoto Iwasaki ,  Chikara Ishizaka

IPC: H01F41/02 ,  H01F41/00

CPC classification number: H01F41/0293 ,  B22F2207/01 ,  B60L50/61 ,  B60L2220/14 ,  B60L2220/16 ,  B60L2220/50 ,  C22C38/002 ,  C22C38/005 ,  H01F1/0577 ,  H01F41/005 ,  H02K1/02 ,  H02K1/04 ,  H02K1/276 ,  Y02T10/6217 ,  Y02T10/641 ,  Y02T10/7077 ,  Y10T428/32

Abstract: A rare earth sintered magnet 10 including a magnet body that includes a rare earth compound, and a protective layer on the magnet body, having a first layer and a second layer in that order from the magnet body side, wherein the surface portion of the magnet body has a higher heavy rare earth element content than the interior of the magnet body that is surrounded by the surface portion, the first layer includes a rare earth oxide, the mass ratio of the heavy rare earth element being 1 or greater with respect to the light rare earth element, and the second layer includes an oxide containing iron and/or boron which is different from the rare earth oxide, the second layer having a lower rare earth oxide content than the first layer.

Abstract translation: 包括稀土类化合物的磁体和磁铁体上的保护层的稀土类烧结磁体10具有从磁铁体侧依次的第一层和第二层，其中磁体的表面部分 本体具有比由表面部包围的磁体的内部更高的重稀土元素含量，第一层包括稀土类氧化物，重稀土类元素的质量比相对于 轻稀土元素，第二层包括与稀土氧化物不同的含有铁和/或硼的氧化物，第二层具有比第一层低的稀土氧化物含量。

公开(公告)号：US10748683B2

公开(公告)日：2020-08-18

申请号：US15285178

申请日：2016-10-04

Applicant: TDK CORPORATION

Inventor： Tetsuya Hidaka ,  Takuma Hayakawa ,  Makoto Iwasaki ,  Ayato Kakoki ,  Naoto Tsukamoto ,  Fumitaka Baba

IPC: H01F41/02 ,  H01F1/053 ,  H01F1/057 ,  B22F3/24 ,  C22C38/12 ,  C22C38/16 ,  C22C33/02 ,  C22C38/14 ,  C22C38/00 ,  C22C38/06 ,  C22C38/10 ,  C22C28/00

Abstract: An R-T-B based sintered magnet includes “R”, “T”, and “B”. “R” represents a rare earth element including at least Tb. “T” represents a metal element except rare earth elements including at least Fe, Cu, Mn, Al, and Co. “B” represents boron or boron and carbon. With respect to 100 mass % of a total mass of the R-T-B based sintered magnet, a content of “R” is 28.0 to 32.0 mass %, a content of Cu is 0.04 to 0.50 mass %, a content of Mn is 0.02 to 0.10 mass %, a content of Al is 0.15 to 0.30 mass %, a content of Co is 0.50 to 3.0 mass %, and a content of “B” is 0.85 to 1.0 mass %. Tb2/Tb1 is 0.40 to less than 1.0, where Tb1 and Tb2 (mass %) denote a content of Tb at a surface portion and at a core portion, respectively.

公开(公告)号：US10523101B2

公开(公告)日：2019-12-31

申请号：US15608067

申请日：2017-05-30

Applicant: TDK CORPORATION

Inventor： Makoto Iwasaki ,  Fumitaka Baba ,  Chikara Ishizaka

IPC: H02K41/03 ,  H02P29/66 ,  H02K1/27 ,  H02P21/22 ,  H02P27/04

Abstract: A motor includes a magnet and a coil. α2=[{(Br2−Br1)/Br1}/(T2−T1)]×100≥−0.10 and α3=[{(Br3−Br1)/Br1}/(T3−T1)]×100≤−0.12 are satisfied. In the magnet, Br1 (mT) is a residual magnetic flux density at T1 (° C.), Br2 (mT) is a residual magnetic flux density at T2 (° C.), and Br3 (mT) is a residual magnetic flux density at T3 (° C.), and α2 (%/° C.) is a temperature coefficient at a target temperature of T2 (° C.) with respect to a reference temperature of T1 (° C.), and α3 (%/° C.) is a temperature coefficient at a target temperature of T3 (° C.) with respect to a reference temperature of T1 (° C.) in conditions of T1=23, T2=60, and T3=180.

公开(公告)号：US10726983B2

公开(公告)日：2020-07-28

申请号：US15439975

申请日：2017-02-23

Applicant: TDK Corporation

Inventor： Jun Hagiwara ,  Fumitaka Baba ,  Makoto Iwasaki ,  Satoshi Koga

IPC: H02K1/00 ,  H01F7/02 ,  H02K1/04

Abstract: A rare earth magnet capable of reducing an eddy current loss by virtue of a low-cost, simple configuration, when mounted in a motor, is to be provided. The rare earth magnet can include a magnet body that includes a rare earth element and iron; and a resistive layer formed on at least one surface of the magnet body, the resistive layer comprising a rare earth element, iron, and oxygen and having an average volume resistivity of 103 Ωcm or more and a thickness of from 3 to 25 μm.