Patents by Inventor Koji Mitake
Koji Mitake has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 11817241Abstract: A magnet structure includes a first sintered magnet, a second sintered magnet, and an intermediate layer disposed between the first sintered magnet and the second sintered magnet. Each of the first sintered magnet and the second sintered magnet independently includes crystal grains containing a rare earth element, a transition metal element, and boron. The intermediate layer contains rare earth element oxide phases and crystal grains containing a rare earth element, transition metal element, and boron. Each of the transition metal elements independently includes Fe or a combination of Fe and Co. An average coverage factor of the rare earth element oxide phases measured on the basis of a cross section perpendicular to the intermediate layer of the magnet structure is within a range of 10% to 69%.Type: GrantFiled: February 26, 2021Date of Patent: November 14, 2023Assignee: TDK CorporationInventors: Taeko Tsubokura, Toshihiro Kuroshima, Koji Mitake, Takeshi Masuda
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Patent number: 11728712Abstract: A magnet temperature information output device is disposed on a rotating electrical machine including a stator and a rotor with a permanent magnet, and is arranged to output temperature information regarding a temperature of the permanent magnet. The magnet temperature information output device includes an element arranged to detect a magnetic flux and output an electrical signal responding to the detected magnetic flux as the temperature information. The element is disposed on the stator.Type: GrantFiled: August 28, 2020Date of Patent: August 15, 2023Assignee: TDK CorporationInventors: Toshio Tomonari, Noritaka Chiyo, Koji Mitake, Toshihiro Kuroshima
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Patent number: 11710994Abstract: In an IPM motor according to one aspect of the present disclosure, in a magnet structure installed in a magnet hole, a first soft magnetic body is located outside a first permanent magnet in a radial direction. Since the first soft magnetic body has a higher electrical resistivity than the electrical resistivity of a rotor core, a situation where an eddy current occurs in the first soft magnetic body is suppressed. In the IPM motor, a deterioration in efficiency caused by an eddy current loss is suppressed, so that the efficiency is improved.Type: GrantFiled: February 23, 2021Date of Patent: July 25, 2023Assignee: TDK CorporationInventors: Tomokazu Shinji, Koji Mitake, Kazuya Uchida
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Patent number: 11611298Abstract: A motor device 100 includes an SPM motor 1 that includes a stator 2 including an iron core 21 and a plurality of windings 23 wound on the iron core 21, and a rotor 3 which is rotatable with respect to a rotation axis and in which a plurality of permanent magnets 33 are mounted along a circumferential direction to form a plurality of magnetic poles in the circumferential direction; and a power supply unit 5 that supplies a current to the plurality of windings 23 of the SPM motor 1. Each of the plurality of magnetic poles is oriented such that directions of axes of easy magnetization are concentrated toward a stator side, and the current supplied from the power supply unit is a trapezoidal wave.Type: GrantFiled: May 14, 2020Date of Patent: March 21, 2023Assignee: TDK CorporationInventors: Nobuyuki Shimbo, Koji Mitake
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Patent number: 11601024Abstract: In an IPM motor, since an end surface portion which is a pressed powder compact made of soft magnetic powder has a higher electrical resistivity than an electrical resistivity of a main body portion made of a laminated steel sheet, compared to when the electrical resistivity of the end surface portion is the same as the electrical resistivity of the main body portion, the occurrence of an eddy current in the end surface portion is further prevented. For this reason, in the IPM motor, a deterioration in efficiency caused by an eddy current loss is prevented, and an improvement in efficiency is realized.Type: GrantFiled: May 7, 2020Date of Patent: March 7, 2023Assignee: TDK CorporationInventors: Nobuyuki Shimbo, Koji Mitake
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Patent number: 11545865Abstract: A rotating electrical machine includes a stator, a rotor with a permanent magnet, a first number of one or more first coils, and a second number of one or more second coils. The second number is different from the first number. The one or more first coils are disposed on the stator. The one or more second coils are disposed on the rotor. The one or more first coils and the one or more second coils are disposed on the stator and the rotor, respectively, in such a manner as to closely oppose each other in a state where the rotor is at a predetermined rotation angle position. The one or more first coils are arranged to induce a voltage in response to a relative position with respect to the one or more second coils.Type: GrantFiled: September 9, 2020Date of Patent: January 3, 2023Assignee: TDK CorporationInventors: Toshio Tomonari, Noritaka Chiyo, Koji Mitake, Toshihiro Kuroshima
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Patent number: 11239714Abstract: In an IPM motor, since a first portion which is a pressed powder compact made of soft magnetic powder and has a lower magnetic permeability and a lower saturation magnetic flux density than those of a main body portion made of a laminated steel sheet is replaced and disposed in the vicinity of an inner arc side portion of a right end portion of a permanent magnet, local demagnetization is prevented.Type: GrantFiled: May 5, 2020Date of Patent: February 1, 2022Assignee: TDK CorporationInventors: Nobuyuki Shimbo, Koji Mitake, Toshihiro Kuroshima
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Publication number: 20210280345Abstract: A magnet structure includes a first sintered magnet, a second sintered magnet, and an intermediate layer disposed between the first sintered magnet and the second sintered magnet. Each of the first sintered magnet and the second sintered magnet independently includes crystal grains containing a rare earth element, a transition metal element, and boron. The intermediate layer contains rare earth element oxide phases and crystal grains containing a rare earth element, transition metal element, and boron. Each of the transition metal elements independently includes Fe or a combination of Fe and Co. An average coverage factor of the rare earth element oxide phases measured on the basis of a cross section perpendicular to the intermediate layer of the magnet structure is within a range of 10% to 69%.Type: ApplicationFiled: February 26, 2021Publication date: September 9, 2021Applicant: TDK CorporationInventors: Taeko TSUBOKURA, Toshihiro KUROSHIMA, Koji MITAKE, Takeshi MASUDA
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Publication number: 20210265880Abstract: In an IPM motor according to one aspect of the present disclosure, in a magnet structure installed in a magnet hole, a first soft magnetic body is located outside a first permanent magnet in a radial direction. Since the first soft magnetic body has a higher electrical resistivity than the electrical resistivity of a rotor core, a situation where an eddy current occurs in the first soft magnetic body is suppressed. In the IPM motor, a deterioration in efficiency caused by an eddy current loss is suppressed, so that the efficiency is improved.Type: ApplicationFiled: February 23, 2021Publication date: August 26, 2021Applicant: TDK CorporationInventors: Tomokazu SHINJI, Koji MITAKE, Kazuya UCHIDA
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Patent number: 11017928Abstract: In a magnet, an insulating layer is fixed to an upper surface of the magnet provided with the insulating layer, but is not fixed to a lower surface of the magnet above the insulating layer. Therefore, even when the magnet expands or contracts due to a temperature change, stress is less likely to occur at an interface between the insulating layer provided on the upper surface of the magnet and the magnet above the insulating layer.Type: GrantFiled: September 6, 2017Date of Patent: May 25, 2021Assignee: TDK CORPORATIONInventors: Nobuo Takagi, Motohisa Murata, Koji Mitake
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Publication number: 20210111604Abstract: A rotating electrical machine includes a stator, a rotor with a permanent magnet, a first number of one or more first coils, and a second number of one or more second coils. The second number is different from the first number. The one or more first coils are disposed on the stator. The one or more second coils are disposed on the rotor. The one or more first coils and the one or more second coils are disposed on the stator and the rotor, respectively, in such a manner as to closely oppose each other in a state where the rotor is at a predetermined rotation angle position. The one or more first coils are arranged to induce a voltage in response to a relative position with respect to the one or more second coils.Type: ApplicationFiled: September 9, 2020Publication date: April 15, 2021Applicant: TDK CorporationInventors: Toshio TOMONARI, Noritaka CHIYO, Koji MITAKE, Toshihiro KUROSHIMA
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Publication number: 20210067010Abstract: A magnet temperature information output device is disposed on a rotating electrical machine including a stator and a rotor with a permanent magnet, and is arranged to output temperature information regarding a temperature of the permanent magnet. The magnet temperature information output device includes an element arranged to detect a magnetic flux and output an electrical signal responding to the detected magnetic flux as the temperature information. The element is disposed on the stator.Type: ApplicationFiled: August 28, 2020Publication date: March 4, 2021Applicant: TDK CorporationInventors: Toshio TOMONARI, Noritaka CHIYO, Koji MITAKE, Toshihiro KUROSHIMA
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Publication number: 20200366144Abstract: In an IPM motor, since a first portion which is a pressed powder compact made of soft magnetic powder and has a lower magnetic permeability and a lower saturation magnetic flux density than those of a main body portion made of a laminated steel sheet is replaced and disposed in the vicinity of an inner arc side portion of a right end portion of a permanent magnet, local demagnetization is prevented.Type: ApplicationFiled: May 5, 2020Publication date: November 19, 2020Applicant: TDK CorporationInventors: Nobuyuki Shimbo, Koji Mitake, Toshihiro Kuroshima
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Publication number: 20200366222Abstract: A motor device 100 includes an SPM motor 1 that includes a stator 2 including an iron core 21 and a plurality of windings 23 wound on the iron core 21, and a rotor 3 which is rotatable with respect to a rotation axis and in which a plurality of permanent magnets 33 are mounted along a circumferential direction to form a plurality of magnetic poles in the circumferential direction; and a power supply unit 5 that supplies a current to the plurality of windings 23 of the SPM motor 1. Each of the plurality of magnetic poles is oriented such that directions of axes of easy magnetization are concentrated toward a stator side, and the current supplied from the power supply unit is a trapezoidal wave.Type: ApplicationFiled: May 14, 2020Publication date: November 19, 2020Applicant: TDK CorporationInventors: Nobuyuki SHIMBO, Koji MITAKE
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Publication number: 20200366145Abstract: In an IPM motor, since an end surface portion which is a pressed powder compact made of soft magnetic powder has a higher electrical resistivity than an electrical resistivity of a main body portion made of a laminated steel sheet, compared to when the electrical resistivity of the end surface portion is the same as the electrical resistivity of the main body portion, the occurrence of an eddy current in the end surface portion is further prevented. For this reason, in the IPM motor, a deterioration in efficiency caused by an eddy current loss is prevented, and an improvement in efficiency is realized.Type: ApplicationFiled: May 7, 2020Publication date: November 19, 2020Applicant: TDK CorporationInventors: Nobuyuki SHIMBO, Koji MITAKE
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Patent number: 10096410Abstract: An R-T-B based sintered magnet having R2T14B crystal grains and a grain boundary formed by two or more adjacent R2T14B crystal grains. An R—Co—Cu—N concentrated part whose concentrations of R, Co, Cu and N are respectively higher than those in the R2T14B crystal grains may be in the grain boundary. An R—O—C concentrated part or an R—O—C—N concentrated part may be further provided in the grain boundary.Type: GrantFiled: July 3, 2014Date of Patent: October 9, 2018Assignee: TDK CORPORATIONInventors: Masashi Miwa, Haruna Nakajima, Koji Mitake, Chikara Ishizaka
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Patent number: 9997284Abstract: A sintered magnet of a preferred embodiment has a composition comprising: R (R is a rare earth element that must contain any one of Nd and Pr.): 29.5 to 33.0 mass %; B: 0.7 to 0.95 mass %; Al: 0.03 to 0.6 mass %; Cu: 0.01 to 1.5 mass %; Co: 3.0 mass % or less (provided that 0 mass % is not included.); Ga: 0.1 to 1.0 mass %; C: 0.05 to 0.3 mass %; O: 0.03 to 0.4 mass %; and Fe and other elements: a balance, and wherein a content of heavy rare earth elements in total is 1.0 mass % or less, and wherein the following relations are satisfied: 0.29<[B]/([Nd]+[Pr])<0.40 and 0.07<([Ga]+[C])/[B]<0.60, where [Nd], [Pr], [B], [C] and [Ga] represent the numbers of atoms of Nd, Pr, B, C and Ga, respectively.Type: GrantFiled: June 21, 2013Date of Patent: June 12, 2018Assignee: TDK CORPORATIONInventors: Masashi Miwa, Atsushi Fujiwara, Eiji Kato, Taeko Tsubokura, Koji Mitake, Chikara Ishizaka
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Publication number: 20180068772Abstract: In a magnet, an insulating layer is fixed to an upper surface of the magnet provided with the insulating layer, but is not fixed to a lower surface of the magnet above the insulating layer. Therefore, even when the magnet expands or contracts due to a temperature change, stress is less likely to occur at an interface between the insulating layer provided on the upper surface of the magnet and the magnet above the insulating layer.Type: ApplicationFiled: September 6, 2017Publication date: March 8, 2018Applicant: TDK CorporationInventors: Nobuo TAKAGI, Motohisa MURATA, Koji MITAKE
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Publication number: 20160086701Abstract: An R-T-B based sintered magnet having R2T14B crystal grains and a grain boundary formed by two or more adjacent R2T14B crystal grains. An R—Co—Cu—N concentrated part whose concentrations of R, Co, Cu and N are respectively higher than those in the R2T14B crystal grains may be in the grain boundary. An R—O—C concentrated part or an R—O—C—N concentrated part may be further provided in the grain boundary.Type: ApplicationFiled: July 3, 2014Publication date: March 24, 2016Applicant: TDK CORPORATIONInventors: Masashi MIWA, Haruna NAKAJIMA, Koji MITAKE, Chikara ISHIZAKA
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Patent number: 9177705Abstract: A sintered rare earth magnet rotating machine and method improve temperature properties and strength having an excellent corrosion resistance. The sintered rare earth magnet includes at least a main phase composed of R2T14B (R represents at least one rare earth element of Nd, Pr or both and T represents at least one transition metal element including Fe or Fe and Co) compound and a grain boundary phase containing a higher proportion of R than the main phase, wherein the main phase includes a heavy rare earth element (one of Dy, Tb or both), at least part of main phase grains of the main phase included in the sintered rare earth magnet includes at least the following regions, low, high and intermediate concentration regions. These regions exist in order of low, high, and intermediate concentration regions, from low concentration region towards the grain boundary phase in the main phase grains.Type: GrantFiled: May 25, 2012Date of Patent: November 3, 2015Assignee: TDK CORPORATIONInventors: Tetsuya Hidaka, Kazuo Sato, Kazuya Sakamoto, Shinya Fujito, Motoaki Hosako, Motohisa Murata, Koji Mitake