公开(公告)号：US20180277288A1

公开(公告)日：2018-09-27

申请号：US15928378

申请日：2018-03-22

Applicant: TDK CORPORATION

Inventor： Makoto IWASAKI ,  Tetsuya HIDAKA ,  Eiji KATO ,  Takuma HAYAKAWA ,  Hidetake KITAOKA

IPC: H01F1/057 ,  C22C38/16 ,  C22C38/14 ,  C22C38/10 ,  C22C38/06 ,  C22C38/00 ,  C22C38/04

Abstract: Provided is an R-T-B based rare earth magnet. R is one or more rare earth elements, T is one or more transition metal elements essentially including Fe or Fe and Co, and B is boron. B content with respect to a total R-T-B based rare earth magnet is 0.80 mass % or more and 0.98 mass % or less. The R-T-B based rare earth magnet includes an R1T4B4 phase.

公开(公告)号：US20180287441A1

公开(公告)日：2018-10-04

申请号：US15936790

申请日：2018-03-27

Applicant: TDK CORPORATION

Inventor： Hidetake KITAOKA ,  Makoto IWASAKI ,  Tetsuya HIDAKA ,  Eiji KATO ,  Takuma HAYAKAWA

IPC: H02K1/27 ,  H02K9/19

Abstract: Provided is a motor including a permanent magnet, in which the permanent magnet includes a high temperature side permanent magnet part exposed to a high temperature inside the motor, and a low temperature side permanent magnet part exposed to a temperature lower than the high temperature inside the motor, and a coercive force of the high temperature side permanent magnet part is higher than the coercive force of the low temperature side permanent magnet part.

公开(公告)号：US20180286544A1

公开(公告)日：2018-10-04

申请号：US15936752

申请日：2018-03-27

Applicant: TDK CORPORATION

Inventor： Takuma HAYAKAWA ,  Makoto IWASAKI ,  Tetsuya HIDAKA ,  Eiji KATO ,  Hidetake KITAOKA

IPC: H01F1/057 ,  H01F41/02

Abstract: Provided is an alloy for R-T-B based rare earth magnet. “R” is one or more of a rare earth element, ‘T’ is one or more of a transition metal element essentially including Fe or Fe and Co, and “B” is boron. The alloy includes a single or a plural number of main phase (A), having a minimum length of 10 μm or more and a maximum length of 30 μm or more and 300 μm or less, in a cross section cut along a thickness direction of the alloy. The main phase (A) includes an R2T14B phase, and an area ratio of the main phase (A) to an entire cross section is 2% or more and 60% or less.

公开(公告)号：US20200312491A1

公开(公告)日：2020-10-01

申请号：US16827851

申请日：2020-03-24

Applicant: TDK CORPORATION

Inventor： Hiroki KAWAMURA ,  Hidetake KITAOKA ,  Makoto IWASAKI

IPC: H01F1/057 ,  H01F41/02 ,  C22C38/16 ,  C22C38/14 ,  C22C38/10 ,  C22C38/06 ,  C22C38/00

Abstract: An alloy for R-T-B based permanent magnet in which R is a rare earth element, T is a combination of Fe and Co, and B is boron. R includes one or more selected from Nd, Pr, Dy, and Tb. The alloy for R-T-B based permanent magnet includes M and C. M is one or more selected from Al, Cu, Zr, and Ga. Relative to 100 mass % of the alloy for R-T-B based permanent magnet, a total content of Nd, Pr, Dy, and Tb is 28.00 mass % or more and 34.00 mass % or less, Co content is 0.05 mass % or more and 3.00 mass % or less, B content is 0.70 mass % or more and 0.95 mass % or less, C content is 0.12 mass % or more and 0.19 mass % or less, a total content of M is more than 0 mass % and 4.00 mass % or less, and Fe is a substantial balance.

公开(公告)号：US20190295752A1

公开(公告)日：2019-09-26

申请号：US16291950

申请日：2019-03-04

Applicant: TDK CORPORATION

Inventor： Hidetake KITAOKA ,  Makoto IWASAKI

IPC: H01F1/057 ,  C22C38/16 ,  C22C38/10 ,  C22C38/06 ,  C22C38/00

Abstract: An R-T-B based permanent magnet in which R is a rare earth element, T is Fe or a combination of Fe and Co, B is boron, and further includes M. The R-T-B based permanent magnet includes main phase grains consisting of R2T14B phase. M at least includes Ga and Zr. The R-T-B based permanent magnet further includes C and O. R content is 29.0 mass % to 33.0 mass %, B content is 0.85 mass % to 1.05 mass %, Ga content is 0.30 mass % to 1.20 mass %, 0 content is 0.03 mass % to 0.20 mass %, and C content is 0.03 mass % to 0.30 mass %. Further, the R-T-B based permanent magnet satisfies 3.48 m(B)−2.67≤m (Zr)≤3.48 m(B)−1.87 in which m (B) (mass %) is B content and m (Zr) (mass %) is Zr content.