Patents by Inventor Hironari Mitarai

Hironari Mitarai 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).

  • Publication number: 20230317370
    Abstract: A field magnet manufacturing method where a bonded magnet's inner surface press-fitted in a yoke has a certain accuracy irrespective of the accuracy of the yoke's outer circumferential surface. A cylindrical bonded magnet from binding magnet particles with a thermosetting resin is fixed in a tubular yoke of magnetic material. The method includes reheating and softening the bonded magnet after thermal curing; and press-fitting in the bonded magnet after the softening step from a tapered portion on one end side of the yoke to press the bonded magnet's outer circumferential surface against the yoke's inner surface. The press-fitting includes feeding the bonded magnet relatively into the yoke while allowing a relative posture variation between the bonded magnet and the yoke so the bonded magnet's inner surface to be remolded into a shape along the inner surface of the yoke exhibits almost the same accuracy as the yoke's inner surface.
    Type: Application
    Filed: June 6, 2023
    Publication date: October 5, 2023
    Applicant: AICHI STEEL CORPORATION
    Inventors: Satoru KAN, Hiroaki HIRANO, Hironari MITARAI, Takumi ASANO, Motonobu FURUYAMA
  • Patent number: 11710598
    Abstract: A field magnet manufacturing method where a bonded magnet's inner surface press-fitted in a yoke has a certain accuracy irrespective of the accuracy of the yoke's outer circumferential surface. A cylindrical bonded magnet from binding magnet particles with a thermosetting resin is fixed in a tubular yoke of magnetic material. The method includes reheating and softening the bonded magnet after thermal curing; and press-fitting in the bonded magnet after the softening step from a tapered portion on one end side of the yoke to press the bonded magnet's outer circumferential surface against the yoke's inner surface. The press-fitting includes feeding the bonded magnet relatively into the yoke while allowing a relative posture variation between the bonded magnet and the yoke so the bonded magnet's inner surface to be remolded into a shape along the inner surface of the yoke exhibits almost the same accuracy as the yoke's inner surface.
    Type: Grant
    Filed: May 29, 2020
    Date of Patent: July 25, 2023
    Assignee: AICHI STEEL CORPORATION
    Inventors: Satoru Kan, Hiroaki Hirano, Hironari Mitarai, Takumi Asano, Motonobu Furuyama
  • Publication number: 20220223341
    Abstract: A field magnet manufacturing method where a bonded magnet's inner surface press-fitted in a yoke has a certain accuracy irrespective of the accuracy of the yoke's outer circumferential surface. A cylindrical bonded magnet from binding magnet particles with a thermosetting resin is fixed in a tubular yoke of magnetic material. The method includes reheating and softening the bonded magnet after thermal curing; and press-fitting in the bonded magnet after the softening step from a tapered portion on one end side of the yoke to press the bonded magnet's outer circumferential surface against the yoke's inner surface. The press-fitting includes feeding the bonded magnet relatively into the yoke while allowing a relative posture variation between the bonded magnet and the yoke so the bonded magnet's inner surface to be remolded into a shape along the inner surface of the yoke exhibits almost the same accuracy as the yoke's inner surface.
    Type: Application
    Filed: May 29, 2020
    Publication date: July 14, 2022
    Applicant: AICHI STEEL CORPORATION
    Inventors: Satoru KAN, Hiroaki HIRANO, Hironari MITARAI, Takumi ASANO, Motonobu FURUYAMA
  • Patent number: 9799446
    Abstract: A production method for an anisotropic bonded magnet includes: filling the annular cavity with a magnet raw material including one or more types of rare-earth anisotropic magnet powder and a binder resin; applying aligning magnetic fields to the magnet raw material being aligned in the softened or molten binder resin, the aligning magnetic fields are applied from an even number of aligning magnetic pole bodies arranged around outer periphery of the annular cavity such that directions of magnetic fields are alternated; subjecting the magnet raw material to a molding to form a compact; rotating the aligning magnetic pole bodies in circumferential direction for a predetermined angle; and applying demagnetization magnetic fields to the compact from the aligning magnetic pole bodies during the alignment step. The demagnetization magnetic fields are in directions for cancelling magnetization of the compact caused by the aligning magnetic fields.
    Type: Grant
    Filed: April 11, 2017
    Date of Patent: October 24, 2017
    Assignee: AICHI STEEL CORPORATION
    Inventors: Yoshinobu Honkura, Hironari Mitarai, Hiroshi Matsuoka, Masayuki Kato, Ikuzou Okumura
  • Publication number: 20170221631
    Abstract: A production method for an anisotropic bonded magnet includes: filling the annular cavity with a magnet raw material including one or more types of rare-earth anisotropic magnet powder and a binder resin; applying aligning magnetic fields to the magnet raw material being aligned in the softened or molten binder resin, the aligning magnetic fields are applied from an even number of aligning magnetic pole bodies arranged around outer periphery of the annular cavity such that directions of magnetic fields are alternated; subjecting the magnet raw material to a molding to form a compact; rotating the aligning magnetic pole bodies in circumferential direction for a predetermined angle; and applying demagnetization magnetic fields to the compact from the aligning magnetic pole bodies during the alignment step. The demagnetization magnetic fields are in directions for cancelling magnetization of the compact caused by the aligning magnetic fields.
    Type: Application
    Filed: April 11, 2017
    Publication date: August 3, 2017
    Inventors: Yoshinobu Honkura, Hironari Mitarai, Hiroshi Matsuoka, Masayuki Kato, Ikuzou Okumura
  • Patent number: 9666341
    Abstract: A method for production of an anisotropic bonded magnet includes: aligning magnetic pole bodies which include an even number of permanent magnets arranged uniformly around an outer periphery of an annular cavity filled with magnetic raw material, aligning magnetic fields to cause rare-earth anisotropic magnet powder to be semi-radially aligned; compressively molding the semi-radially aligned magnet raw material to obtain an annular compact; discharging the compact from the annular cavity; demagnetizing causing the aligning magnetic pole bodies to relatively move only in circumferential direction with respect to the compact after the molding step thereby to apply demagnetization magnetic fields to the compact; The demagnetization magnetic fields are applied from the aligning magnetic pole bodies with opposite poles to those during the alignment step, and the demagnetization magnetic fields are in directions for cancelling the magnetization of the compact caused by the aligning magnetic fields.
    Type: Grant
    Filed: April 5, 2011
    Date of Patent: May 30, 2017
    Assignee: AICHI STEEL CORPORATION
    Inventors: Yoshinobu Honkura, Hironari Mitarai, Hiroshi Matsuoka, Masayuki Kato, Ikuzou Okumura
  • Patent number: 9312055
    Abstract: A production method for a case-integrated bonded magnet includes: filling a tubular cavity with a magnet raw material that includes a rare-earth magnet powder and a thermosetting resin binder; heating the magnet raw material to cause the thermosetting resin softened or melted while compressively molding the magnet raw material to obtain a tubular compact; discharging the tubular compact from the tubular cavity while press-fitting the tubular compact into a metal tubular case having an inner peripheral surface coaxial with the tubular cavity; and heat-curing the tubular compact with the tubular case to cure the thermosetting resin. The tubular compact press-fitted into the tubular case is thermally cured thereby causing the tubular compact to transform to a tubular bonded magnet, which expands unexpectedly due to heat.
    Type: Grant
    Filed: April 5, 2011
    Date of Patent: April 12, 2016
    Assignee: AICHI STEEL CORPORATION
    Inventors: Yoshinobu Honkura, Hironari Mitarai, Hiroshi Matsuoka, Masayuki Kato, Ikuzou Okumura
  • Publication number: 20130093121
    Abstract: A method for production of an anisotropic bonded magnet includes: aligning magnetic pole bodies which include an even number of permanent magnets arranged uniformly around an outer periphery of an annular cavity filled with magnetic raw material, aligning magnetic fields to cause rare-earth anisotropic magnet powder to be semi-radially aligned; compressively molding the semi-radially aligned magnet raw material to obtain an annular compact; discharging the compact from the annular cavity; demagnetizing causing the aligning magnetic pole bodies to relatively move only in circumferential direction with respect to the compact after the molding step thereby to apply demagnetization magnetic fields to the compact. The demagnetization magnetic fields are applied from the aligning magnetic pole bodies with opposite poles to those during the alignment step, and the demagnetization magnetic fields are in directions for cancelling the magnetization of the compact caused by the aligning magnetic fields.
    Type: Application
    Filed: April 5, 2011
    Publication date: April 18, 2013
    Applicant: AICHI STEEL CORPORATION
    Inventors: Yoshinobu Honkura, Hironari Mitarai, Hiroshi Matsuoka, Masayuki Kato, Ikuzou Okumura
  • Publication number: 20130069747
    Abstract: A production method for a case-integrated bonded magnet includes: filling a tubular cavity with a magnet raw material that includes a rare-earth magnet powder and a thermosetting resin binder; heating the magnet raw material to cause the thermosetting resin softened or melted while compressively molding the magnet raw material to obtain a tubular compact; discharging the tubular compact from the tubular cavity while press-fitting the tubular compact into a metal tubular case having an inner peripheral surface coaxial with the tubular cavity; and heat-curing the tubular compact with the tubular case to cure the thermosetting resin. The tubular compact press-fitted into the tubular case is thermally cured thereby causing the tubular compact to transform to a tubular bonded magnet, which expands unexpectedly due to heat.
    Type: Application
    Filed: April 5, 2011
    Publication date: March 21, 2013
    Applicant: Aichi Steel Corporation
    Inventors: Yoshinobu Honkura, Hironari Mitarai, Hiroshi Matsuoka, Masayuki Kato, Ikuzou Okumura
  • Publication number: 20110248591
    Abstract: An anisotropic bonded magnet molded in a ring shape to be used to excite a brush-equipped direct current motor. A magnetic flux density distribution in each of magnetic pole sections of the ring shape forms an asymmetric distribution which includes a magnetic flux density reduced portion wherein the absolute value rises from a neutral axis opposite to a rotation direction of an armature with a delay with respect to a rotation direction of the armature, and in which the absolute value falls more rapidly than a rise thereof in the rotation direction of the armature with respect to a neutral axis in the rotation direction of the armature.
    Type: Application
    Filed: May 6, 2011
    Publication date: October 13, 2011
    Applicant: Aichi Steel Corporation
    Inventors: Yoshinobu Honkura, Hironari Mitarai, Hiroshi Matsuoka, Yoji Hashimoto
  • Patent number: 7812484
    Abstract: To improve resistance of a motor device against an organic solvent and to suppress degradation in performance of the motor device with time. In a motor device, an excitation magnet is formed using a hollow-cylinder shaped anisotropic bonded magnet 13. This bonded magnet 13 is press-fitted in a housing 12 and is held. The bonded magnet 13 is formed of a hollow-cylinder shaped anisotropic rare earth bonded magnet which is obtained by compounding an anisotropic rare earth magnet powder with a phenol-novolac type epoxy resin, followed by molding. The anisotropic rare earth bonded magnet 13 is press-fitted along an inner peripheral portion of the housing 12, and on an exposed surface layer of the anisotropic rare earth bonded magnet press-fitted in the housing, a coating layer is formed by an infiltration treatment using a polyamide-imide-based resin.
    Type: Grant
    Filed: November 29, 2005
    Date of Patent: October 12, 2010
    Assignee: Aichi Steel Corporation
    Inventors: Yoshinobu Honkura, Hiroshi Matsuoka, Atsushi Kano, Kenji Noguchi, Hironari Mitarai, Satoru Kan
  • Publication number: 20090127958
    Abstract: The rectifying characteristic of a brush-equipped direct current machine is improved, and the life of the machine is extended. As illustrated in FIG. 2, a magnetic flux density reduced portion in which the magnetic flux density is reduced is formed in a magnetic pole section of an anisotropic bonded magnet. The position in the magnetic pole section formed with the magnetic flux density reduced portion is formed at the position at which, when a rectifier coil moves in a rectification section, the absolute value of the density of a magnetic flux penetrating the rectifier coil is increased due to the influence of the magnetic flux density reduced portion. Thus, an inverse voltage can be induced in the rectifier coil in the direction of inversion current during a rectification period. It is therefore possible to facilitate the inversion of the current, and to compensate for inadequate rectification and improve the rectifying characteristic.
    Type: Application
    Filed: August 3, 2006
    Publication date: May 21, 2009
    Inventors: Yoshinobu Honkura, Hironari Mitarai, Hiroshi Matsuoka, Yoji Hashimoto
  • Publication number: 20080124235
    Abstract: [Object] To improve resistance of a motor device against an organic solvent and to suppress degradation in performance of the motor device with time. [Solving Means] In a motor device, an excitation magnet is formed using a hollow-cylinder shaped anisotropic bonded magnet 13. This bonded magnet 13 is press-fitted in a housing 12 and is held. The bonded magnet 13 is formed of a hollow-cylinder shaped anisotropic rare earth bonded magnet which is obtained by compounding an anisotropic rare earth magnet powder with a phenol-novolac type epoxy resin, followed by molding. The anisotropic rare earth bonded magnet 13 is press-fitted along an inner peripheral portion of the housing 12, and on an exposed surface layer of the anisotropic rare earth bonded magnet press-fitted in the housing, a coating layer is formed by an infiltration treatment using a polyamide-imide-based resin.
    Type: Application
    Filed: November 29, 2005
    Publication date: May 29, 2008
    Inventors: Yoshinobu Honkura, Hiroshi Matsuoka, Atsushi Kano, Kenji Noguchi, Hironari Mitarai, Satoru Kan
  • Patent number: 7367791
    Abstract: A device capable of producing an annular magnet or arcuate magnet with excellent dimensional accuracy and magnet performance, of which the mass is not greatly scattered. The device for producing the annular magnet, for example, includes a preforming section for obtaining an annular preformed body from a compound of a mixture of an anisotropic magnet powder and a thermosetting resin, a magnetic field orienting and forming section for obtaining an annular intermediate formed body by subjecting the annular preformed body to orienting and pressure-forming, a main forming section for obtaining an annular magnet by further forming the annular intermediate formed body, and a work transferring section for transferring works.
    Type: Grant
    Filed: November 19, 2004
    Date of Patent: May 6, 2008
    Assignee: Aichi Steel Corporation
    Inventors: Tetsu Murata, Ryoji Makino, Yuji Takemoto, Katsuyuki Hiraiwa, Shinji Kawamura, Takahiro Nishiyama, Yoshinobu Honkura, Hironari Mitarai, Kenji Noguchi
  • Patent number: 7357880
    Abstract: The bonded magnet of the present invention, in which average particle diameter and compounding ratio are specified, is comprised of Cobalt-less R1 d-HDDR coarse magnet powder that has been surface coated with surfactant, R2 fine magnet powder that has been surface coated with surfactant (R1 and R2 are rare-earth metals), and a resin which is a binder. The resin, a ferromagnetic buffer in which R2 fine magnet powder is uniformly dispersed, envelops the outside of the Cobalt-less R1 d-HDDR coarse magnet powder. Despite using Cobalt-less R1 d-HDDR anisotropic magnet powder, which is susceptible to fracturing and therefore vulnerable to oxidation, the bonded magnet of the present invention exhibits high magnetic properties along with extraordinary heat resistance.
    Type: Grant
    Filed: November 18, 2003
    Date of Patent: April 15, 2008
    Assignee: Aichi Steel Corporation
    Inventors: Yoshinobu Honkura, Norihiko Hamada, Hironari Mitarai, Kenji Noguchi
  • Publication number: 20060110484
    Abstract: A device capable of producing an annular magnet or arcuate magnet with excellent dimensional accuracy and magnet performance, of which the mass is not greatly scattered. The device for producing the annular magnet, for example, includes a preforming section for obtaining an annular preformed body from a compound of a mixture of an anisotropic magnet powder and a thermosetting resin, a magnetic field orienting and forming section for obtaining an annular intermediate formed body by subjecting the annular preformed body to orienting and pressure-forming, a main forming section for obtaining an annular magnet by further forming the annular intermediate formed body, and a work transferring section for transferring works.
    Type: Application
    Filed: November 19, 2004
    Publication date: May 25, 2006
    Applicant: AICHI STEEL CORPORATION
    Inventors: Tetsu Murata, Ryoji Makino, Yuji Takemoto, Katsuyuki Hiraiwa, Shinji Kawamura, Takahiro Nishiyama, Yoshinobu Honkura, Hironari Mitarai, Kenji Noguchi
  • Patent number: 6917132
    Abstract: The challenge to be solved by the present invention is the miniaturization of a 1-300 W class of motor. This can be achieved by using a hollow-cylinder shaped anisotropic bonded magnet magnetized in a 4-pole configuration. The anisotropic bonded magnet has a maximum energy product approximately 4 times greater than the conventional sintered ferrite magnets. The use of a 4-pole configuration shortens the magnetic path length of the individual magnetic circuits and the magnetic force contributing to the torque is increased. When the torque is kept the same as in the conventional motor, the length of the electromagnetic rotor core and the axial magnet length can be reduced. In this fashion, 1-300 W class motors can be reduced in size.
    Type: Grant
    Filed: December 10, 2002
    Date of Patent: July 12, 2005
    Assignee: Aichi Steel Corporation
    Inventors: Yoshinobu Honkura, Yoji Hashimoto, Hironari Mitarai
  • Publication number: 20050076974
    Abstract: The bonded magnet of the present invention, in which average particle diameter and compounding ratio are specified, is comprised of Cobalt-less R1 d-HDDR coarse magnet powder that has been surface coated with surfactant, R2 fine magnet powder that has been surface coated with surfactant (R1 and R2 are rare-earth metals), and a resin which is a binder. The resin, a ferromagnetic buffer in which R2 fine magnet powder is uniformly dispersed, envelops the outside of the Cobalt-less R1 d-HDDR coarse magnet powder. Despite using Cobalt-less R1 d-HDDR anisotropic magnet powder, which is susceptible to fracturing and therefore vulnerable to oxidation, the bonded magnet of the present invention exhibits high magnetic properties along with extraordinary heat resistance.
    Type: Application
    Filed: November 18, 2003
    Publication date: April 14, 2005
    Applicant: AICHI STEEL CORPORATION
    Inventors: Yoshinobu Honkura, Norihiko Hamada, Hironari Mitarai, Kenji Noguchi
  • Publication number: 20040201300
    Abstract: The challenge to be solved by the present invention is the miniaturization of a 1-300 W class of motor. This can be achieved by using a hollow-cylinder shaped anisotropic bonded magnet magnetized in a 4-pole configuration. The anisotropic bonded magnet has a maximum energy product approximately 4 times greater than the conventional sintered ferrite magnets. The use of a 4-pole configuration shortens the magnetic path length of the individual magnetic circuits and the magnetic force contributing to the torque is increased. When the torque is kept the same as in the conventional motor, the length of the electromagnetic rotor core and the axial magnet length can be reduced. In this fashion, 1-300 W class motors can be reduced in size.
    Type: Application
    Filed: April 30, 2004
    Publication date: October 14, 2004
    Applicant: AICHI STEEL CORPORATION
    Inventors: Yoshinobu Honkura, Yoji Hashimoto, Hironari Mitarai
  • Publication number: 20030111921
    Abstract: The challenge to be solved by the present invention is the miniaturization of a 1-300 W class of motor. This can be achieved by using a hollow-cylinder shaped anisotropic bonded magnet magnetized in a 4-pole configuration. The anisotropic bonded magnet has a maximum energy product approximately 4 times greater than the conventional sintered ferrite magnets. The use of a 4-pole configuration shortens the magnetic path length of the individual magnetic circuits and the magnetic force contributing to the torque is increased. When the torque is kept the same as in the conventional motor, the length of the electromagnetic rotor core and the axial magnet length can be reduced. In this fashion, 1-300 W class motors can be reduced in size.
    Type: Application
    Filed: December 10, 2002
    Publication date: June 19, 2003
    Applicant: AICHI STEEL CORPORATION
    Inventors: Yoshinobu Honkura, Yoji Hashimoto, Hironari Mitarai