Patents by Inventor Fumitaka Baba
Fumitaka Baba 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: 10748683Abstract: 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.Type: GrantFiled: October 4, 2016Date of Patent: August 18, 2020Assignee: TDK CORPORATIONInventors: Tetsuya Hidaka, Takuma Hayakawa, Makoto Iwasaki, Ayato Kakoki, Naoto Tsukamoto, Fumitaka Baba
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Patent number: 10726983Abstract: 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 ?cm or more and a thickness of from 3 to 25 ?m.Type: GrantFiled: February 23, 2017Date of Patent: July 28, 2020Assignee: TDK CORPORATIONInventors: Jun Hagiwara, Fumitaka Baba, Makoto Iwasaki, Satoshi Koga
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Patent number: 10523101Abstract: A motor includes a magnet and a coil. ?2=[{(Br2?Br1)/Br1}/(T2?T1)]×100??0.10 and ?3=[{(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 ?2 (%/° C.) is a temperature coefficient at a target temperature of T2 (° C.) with respect to a reference temperature of T1 (° C.), and ?3 (%/° 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.Type: GrantFiled: May 30, 2017Date of Patent: December 31, 2019Assignee: TDK CORPORATIONInventors: Makoto Iwasaki, Fumitaka Baba, Chikara Ishizaka
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Publication number: 20170346432Abstract: A motor includes a magnet and a coil. ?2=[{(Br2?Br1)/Br1}/(T2?T1)]×100??0.10 and ?3=[{(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 ?2 (%/° C.) is a temperature coefficient at a target temperature of T2 (° C.) with respect to a reference temperature of T1 (° C.), and ?3 (%/° 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.Type: ApplicationFiled: May 30, 2017Publication date: November 30, 2017Applicant: TDK CORPORATIONInventors: Makoto IWASAKI, Fumitaka BABA, Chikara ISHIZAKA
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Publication number: 20170278609Abstract: 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, where the rare earth magnet comprising: a magnet body comprising 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 ?cm or more and a thickness of from 3 to 25 ?m, as is shown in FIG. 2.Type: ApplicationFiled: February 23, 2017Publication date: September 28, 2017Applicant: TDK CorporationInventors: Jun HAGIWARA, Fumitaka BABA, Makoto IWASAKI, Satoshi KOGA
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Publication number: 20170103835Abstract: 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.Type: ApplicationFiled: October 4, 2016Publication date: April 13, 2017Applicant: TDK CORPORATIONInventors: Tetsuya HIDAKA, Takuma HAYAKAWA, Makoto IWASAKI, Ayato KAKOKI, Naoto TSUKAMOTO, Fumitaka BABA
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Patent number: 9548157Abstract: The present invention provides a sintered magnet having superior residual magnetic flux density and coercive force. The sintered magnet of the present invention comprises a group of R-T-B based rare earth magnet crystal particles 2 having a core 4 and a shell 6 covering the core 4, the mass ratio of a heavy rare earth element in the shell 6 is higher than the mass ratio of a heavy rare earth element in the core 4, and the thickest part of the shell 6 in the crystal particles 2 faces a grain boundary triple junction 1. A lattice defect 3 is formed between the core 4 and the shell 6.Type: GrantFiled: March 29, 2011Date of Patent: January 17, 2017Assignee: TDK CORPORATIONInventors: Makoto Iwasaki, Ryota Kunieda, Fumitaka Baba, Satoshi Tanaka, Yoshinori Fujikawa
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Patent number: 9350203Abstract: Provided is a rare earth sintered magnet 10 comprising a group of main phase grains 2 each composed of an R-T-B-based rare earth magnet comprising a core 4 and a shell 6 covering the core 4, wherein a thickness of the shell 6 is 500 nm or less, R includes a light rare earth element and a heavy rare earth element, and a Zr compound 8 is present in a grain boundary phase 7 of the group of main phase grains 2 and/or the shell 6. Also provided are a motor comprising the rare earth sintered magnet 10 and an automobile comprising the motor.Type: GrantFiled: March 30, 2011Date of Patent: May 24, 2016Assignee: TDK CorporationInventors: Fumitaka Baba, Satoshi Tanaka, Makoto Iwasaki, Chikara Ishizaka
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Patent number: 9154004Abstract: In the rare earth sintered magnet, the ratio of R2 to the sum of R1 and R2 that are contained in crystal grain boundaries surrounding the crystal grains in the rare earth sintered magnet body is higher than the ratio of R2 to the sum of R1 and R2 in the crystal grains, and the concentration of R2 increases from the central portion of the rare earth sintered magnet body toward the surface of the rare earth sintered magnet body. In addition, the degree of unevenness in residual magnetic flux density on the surface of the rare earth sintered magnet body is smaller than 3.0%.Type: GrantFiled: March 4, 2011Date of Patent: October 6, 2015Assignee: TDK CORPORATIONInventors: Makoto Iwasaki, Fumitaka Baba, Satoshi Tanaka, Hideki Sasaki, Takahide Kurahashi, Hitoshi Maro, Keiichi Morimoto, Seiichi Endo
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Publication number: 20140335268Abstract: 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.Type: ApplicationFiled: July 25, 2014Publication date: November 13, 2014Inventors: Satoshi Tanaka, Fumitaka Baba, Makoto Iwasaki, Chikara Ishizaka
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Patent number: 8823478Abstract: 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.Type: GrantFiled: March 28, 2011Date of Patent: September 2, 2014Assignee: TDK CorporationInventors: Satoshi Tanaka, Fumitaka Baba, Makoto Iwasaki, Chikara Ishizaka
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Patent number: 8394450Abstract: The process for producing a magnet according to the invention is characterized by comprising a first step in which a heavy rare earth compound containing Dy or Tb as a heavy rare earth element is adhered onto a sintered compact of a rare earth magnet and a second step in which the heavy rare earth compound-adhered sintered compact is subjected to heat treatment, wherein the heavy rare earth compound is a Dy or Tb iron compound.Type: GrantFiled: May 28, 2009Date of Patent: March 12, 2013Assignee: TDK CorporationInventors: Fumitaka Baba, Hideki Nakamura, Satoshi Tanaka, Takeshi Masuda
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Publication number: 20130049910Abstract: 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.Type: ApplicationFiled: March 28, 2011Publication date: February 28, 2013Applicant: TDK CorporationInventors: Satoshi Tanaka, Fumitaka Baba, Makoto Iwasaki, Chikara Ishizaka
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Publication number: 20130026870Abstract: Provided is a rare earth sintered magnet 10 comprising a group of main phase grains 2 each composed of an R-T-B-based rare earth magnet comprising a core 4 and a shell 6 covering the core 4, wherein a thickness of the shell 6 is 500 nm or less, R includes a light rare earth element and a heavy rare earth element, and a Zr compound 8 is present in a grain boundary phase 7 of the group of main phase grains 2 and/or the shell 6. Also provided are a motor comprising the rare earth sintered magnet 10 and an automobile comprising the motor.Type: ApplicationFiled: March 30, 2011Publication date: January 31, 2013Applicant: TDK CorporationInventors: Fumitaka Baba, Satoshi Tanaka, Makoto Iwasaki, Chikara Ishizaka
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Publication number: 20130009503Abstract: The present invention provides a sintered magnet having superior residual magnetic flux density and coercive force. The sintered magnet of the present invention comprises a group of R-T-B based rare earth magnet crystal particles 2 having a core 4 and a shell 6 covering the core 4, the mass ratio of a heavy rare earth element in the shell 6 is higher than the mass ratio of a heavy rare earth element in the core 4, and the thickest part of the shell 6 in the crystal particles 2 faces a grain boundary triple junction 1. A lattice defect 3 is formed between the core 4 and the shell 6.Type: ApplicationFiled: March 29, 2011Publication date: January 10, 2013Applicant: TDK CorporationInventors: Makoto Iwasaki, Ryota Kunieda, Fumitaka Baba, Satoshi Tanaka, Yoshinori Fujikawa
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Publication number: 20120139388Abstract: In the rare earth sintered magnet, the ratio of R2 to the sum of R1 and R2 that are contained in crystal grain boundaries surrounding the crystal grains in the rare earth sintered magnet body is higher than the ratio of R2 to the sum of R1 and R2 in the crystal grains, and the concentration of R2 increases from the central portion of the rare earth sintered magnet body toward the surface of the rare earth sintered magnet body. In addition, the degree of unevenness in residual magnetic flux density on the surface of the rare earth sintered magnet body is smaller than 3.0%.Type: ApplicationFiled: March 4, 2011Publication date: June 7, 2012Applicant: TDK CORPORATIONInventors: Makoto Iwasaki, Fumitaka Baba, Satoshi Tanaka, Hideki Sasaki, Takahide Kurahashi, Hitoshi Maro, Keiichi Morimoto, Seiichi Endo
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Patent number: 8152936Abstract: There is provided a rare earth magnet with excellent Br and HcJ values. The rare earth magnet according to a preferred embodiment of the invention is characterized by being composed mainly of R (where R is at least one element selected from among rare earth elements including Y), B, Al, Cu, Zr, Co, O, C and Fe, wherein the content of each element is R: 25-34 wt %, B: 0.85-0.98 wt %, Al: 0.03-0.3 wt %, Cu: 0.01-0.15 wt %, Zr: 0.03-0.25 wt %, Co: ?3 wt % (but not 0 wt %), O: ?0.2 wt %, C: 0.03-0.15 wt % and Fe: remainder.Type: GrantFiled: June 27, 2008Date of Patent: April 10, 2012Assignee: TDK CorporationInventors: Taeko Tsubokura, Makoto Iwasaki, Makoto Nakane, Fumitaka Baba
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Patent number: 7858023Abstract: A method for producing a rare earth sintered magnet uses granules having an excellent fluidity to improve the dimensional accuracy and production of a compact formed of the granules without significant property losses. The granules are formed by adding an organic liquid to primary alloy particles having a predetermined composition to produce granules having the primary alloy particles adhered together by the organic liquid. Preferably, from 1.5 to 15.0% by weight of the organic liquid is added to the primary alloy particles.Type: GrantFiled: June 28, 2005Date of Patent: December 28, 2010Assignee: TDK CorporationInventors: Yasushi Enokido, Fumitaka Baba, Chikara Ishizaka, Takeshi Masuda
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Publication number: 20100233016Abstract: There is provided a rare earth magnet with excellent Br and HcJ values. The rare earth magnet according to a preferred embodiment of the invention is characterized by being composed mainly of R (where R is at least one element selected from among rare earth elements including Y), B, Al, Cu, Zr, Co, O, C and Fe, wherein the content of each element is R: 25-34 wt %, B: 0.85-0.98 wt %, Al: 0.03-0.3 wt %, Cu: 0.01-0.15 wt %, Zr: 0.03-0.25 wt %, Co: ?3 wt % (but not 0 wt %), O: ?0.2 wt %, C: 0.03-0.15 wt % and Fe: remainder.Type: ApplicationFiled: June 27, 2008Publication date: September 16, 2010Applicant: TDK CorporationInventors: Taeko Tsubokura, Makoto Iwasaki, Makoto Nakane, Fumitaka Baba
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Publication number: 20100129538Abstract: The invention provides a process for producing a magnet that not only allows satisfactory Br and HcJ values to be achieved but can also yield a magnet with a sufficiently large squareness ratio. The process for producing a magnet according to the invention is characterized by comprising a first step in which a heavy rare earth compound containing a heavy rare earth element is adhered onto a rare earth magnet sintered compact, and a second step in which the heavy rare earth compound-adhered sintered compact is subjected to heat treatment. The heavy rare earth compound is a hydride of the heavy rare earth element.Type: ApplicationFiled: March 31, 2008Publication date: May 27, 2010Applicant: TDK CORPORATIONInventors: Ryota Kunieda, Makoto Nakane, Fumitaka Baba, Makoto Iwasaki, Satoshi Tanaka, Hideki Nakamura