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).
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Publication number: 20230317370Abstract: 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: ApplicationFiled: June 6, 2023Publication date: October 5, 2023Applicant: AICHI STEEL CORPORATIONInventors: Satoru KAN, Hiroaki HIRANO, Hironari MITARAI, Takumi ASANO, Motonobu FURUYAMA
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Patent number: 11710598Abstract: 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: GrantFiled: May 29, 2020Date of Patent: July 25, 2023Assignee: AICHI STEEL CORPORATIONInventors: Satoru Kan, Hiroaki Hirano, Hironari Mitarai, Takumi Asano, Motonobu Furuyama
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Publication number: 20220223341Abstract: 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: ApplicationFiled: May 29, 2020Publication date: July 14, 2022Applicant: AICHI STEEL CORPORATIONInventors: Satoru KAN, Hiroaki HIRANO, Hironari MITARAI, Takumi ASANO, Motonobu FURUYAMA
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Patent number: 9799446Abstract: 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: GrantFiled: April 11, 2017Date of Patent: October 24, 2017Assignee: AICHI STEEL CORPORATIONInventors: Yoshinobu Honkura, Hironari Mitarai, Hiroshi Matsuoka, Masayuki Kato, Ikuzou Okumura
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Publication number: 20170221631Abstract: 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: ApplicationFiled: April 11, 2017Publication date: August 3, 2017Inventors: Yoshinobu Honkura, Hironari Mitarai, Hiroshi Matsuoka, Masayuki Kato, Ikuzou Okumura
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Patent number: 9666341Abstract: 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: GrantFiled: April 5, 2011Date of Patent: May 30, 2017Assignee: AICHI STEEL CORPORATIONInventors: Yoshinobu Honkura, Hironari Mitarai, Hiroshi Matsuoka, Masayuki Kato, Ikuzou Okumura
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Patent number: 9312055Abstract: 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: GrantFiled: April 5, 2011Date of Patent: April 12, 2016Assignee: AICHI STEEL CORPORATIONInventors: Yoshinobu Honkura, Hironari Mitarai, Hiroshi Matsuoka, Masayuki Kato, Ikuzou Okumura
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Publication number: 20130093121Abstract: 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: ApplicationFiled: April 5, 2011Publication date: April 18, 2013Applicant: AICHI STEEL CORPORATIONInventors: Yoshinobu Honkura, Hironari Mitarai, Hiroshi Matsuoka, Masayuki Kato, Ikuzou Okumura
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Publication number: 20130069747Abstract: 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: ApplicationFiled: April 5, 2011Publication date: March 21, 2013Applicant: Aichi Steel CorporationInventors: Yoshinobu Honkura, Hironari Mitarai, Hiroshi Matsuoka, Masayuki Kato, Ikuzou Okumura
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Publication number: 20110248591Abstract: 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: ApplicationFiled: May 6, 2011Publication date: October 13, 2011Applicant: Aichi Steel CorporationInventors: Yoshinobu Honkura, Hironari Mitarai, Hiroshi Matsuoka, Yoji Hashimoto
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Patent number: 7812484Abstract: 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: GrantFiled: November 29, 2005Date of Patent: October 12, 2010Assignee: Aichi Steel CorporationInventors: Yoshinobu Honkura, Hiroshi Matsuoka, Atsushi Kano, Kenji Noguchi, Hironari Mitarai, Satoru Kan
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Publication number: 20090127958Abstract: 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: ApplicationFiled: August 3, 2006Publication date: May 21, 2009Inventors: Yoshinobu Honkura, Hironari Mitarai, Hiroshi Matsuoka, Yoji Hashimoto
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Publication number: 20080124235Abstract: [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: ApplicationFiled: November 29, 2005Publication date: May 29, 2008Inventors: Yoshinobu Honkura, Hiroshi Matsuoka, Atsushi Kano, Kenji Noguchi, Hironari Mitarai, Satoru Kan
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Patent number: 7367791Abstract: 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: GrantFiled: November 19, 2004Date of Patent: May 6, 2008Assignee: Aichi Steel CorporationInventors: Tetsu Murata, Ryoji Makino, Yuji Takemoto, Katsuyuki Hiraiwa, Shinji Kawamura, Takahiro Nishiyama, Yoshinobu Honkura, Hironari Mitarai, Kenji Noguchi
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Patent number: 7357880Abstract: 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: GrantFiled: November 18, 2003Date of Patent: April 15, 2008Assignee: Aichi Steel CorporationInventors: Yoshinobu Honkura, Norihiko Hamada, Hironari Mitarai, Kenji Noguchi
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Publication number: 20060110484Abstract: 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: ApplicationFiled: November 19, 2004Publication date: May 25, 2006Applicant: AICHI STEEL CORPORATIONInventors: Tetsu Murata, Ryoji Makino, Yuji Takemoto, Katsuyuki Hiraiwa, Shinji Kawamura, Takahiro Nishiyama, Yoshinobu Honkura, Hironari Mitarai, Kenji Noguchi
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Patent number: 6917132Abstract: 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: GrantFiled: December 10, 2002Date of Patent: July 12, 2005Assignee: Aichi Steel CorporationInventors: Yoshinobu Honkura, Yoji Hashimoto, Hironari Mitarai
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Publication number: 20050076974Abstract: 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: ApplicationFiled: November 18, 2003Publication date: April 14, 2005Applicant: AICHI STEEL CORPORATIONInventors: Yoshinobu Honkura, Norihiko Hamada, Hironari Mitarai, Kenji Noguchi
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Publication number: 20040201300Abstract: 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: ApplicationFiled: April 30, 2004Publication date: October 14, 2004Applicant: AICHI STEEL CORPORATIONInventors: Yoshinobu Honkura, Yoji Hashimoto, Hironari Mitarai
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Publication number: 20030111921Abstract: 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: ApplicationFiled: December 10, 2002Publication date: June 19, 2003Applicant: AICHI STEEL CORPORATIONInventors: Yoshinobu Honkura, Yoji Hashimoto, Hironari Mitarai