Patents by Inventor Kazuto Sakai
Kazuto Sakai 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: 20090261679Abstract: An object of the present invention is to provide an internal permanent magnet type rotating electrical machine capable of maintaining compactness and high output and reducing vibration and noise caused by electromagnetic force. The rotating electrical machine of the present invention has an annular stator and a rotor that is arranged inside the stator with an air gap interposed between the stator and the rotor. The stator has a stator iron core provided with a plurality of slots at circumferential intervals and a coil received in each of the slots.Type: ApplicationFiled: August 31, 2006Publication date: October 22, 2009Applicants: KABUSHIKI KAISHA TOSHIBA, TOSHIBA INDUSTRIAL PRODUCTS MANUFACTURING CORPORATIONInventors: Kazuto Sakai, Norio Takahashi, Masanori Arata, Motoyasu Mochizuki, Masakatsu Matsubara, Yasuo Hirano, Takashi Hanai
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Publication number: 20090261774Abstract: A variable-flux motor drive system including a permanent-magnet motor including a permanent magnet, an inverter to drive the permanent-magnet motor, and a magnetize device to pass a magnetizing current for controlling flux of the permanent magnet. The permanent magnet is a variable magnet whose flux density is variable depending on a magnetizing current from the inverter. The magnetize device passes a magnetizing current that is over a magnetization saturation zone of magnetic material of the variable magnet. This system improves a flux repeatability of the variable magnet and a torque accuracy.Type: ApplicationFiled: July 24, 2007Publication date: October 22, 2009Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Kazuaki Yuuki, Kazuto Sakai, Hiroshi Mochikawa
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Publication number: 20090236923Abstract: An object of the present invention is to provide a permanent-magnet-type rotating electrical machine capable of realizing a variable-speed operation at high output in a wide range from low speed to high speed and improving efficiency and reliability. The permanent-magnet-type rotating electrical machine of the present invention includes a stator provided with a coil and a rotor in which there are arranged a low-coercive-force permanent magnet whose coercive force is of such a level that a magnetic field created by a current of the stator coil may irreversibly change the flux density of the magnet and a high-coercive-force permanent magnet whose coercive force is equal to or larger than twice that of the low-coercive-force permanent magnet.Type: ApplicationFiled: August 23, 2006Publication date: September 24, 2009Inventors: Kazuto Sakai, Masanori Arata
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Publication number: 20080093944Abstract: For an electrical reluctance rotary machine, a stator has a winding as an armature, and a rotor has permanent magnet implanting slots provided in a rotor core at lateral sides magnetic poles configured to produce reluctance torque along directions of magnetic flux passing through the magnetic poles to produce reluctance torque, and permanent magnets inserted in the permanent magnet implanting slots so as to cancel magnetic flux of the armature intersecting that magnetic flux, to control a magnetic field leaking at ends of the magnetic poles, having circumferential magnetic concavo-convex. The electrical reluctance rotary machine is configured to meet a relationship, such that 1.6 ? P × W pm R ? 1.9 where Wpm [mm] is a width of permanent magnet, R [mm] is an outer-diametrical radius of the rotor, and P is the number of poles.Type: ApplicationFiled: October 19, 2007Publication date: April 24, 2008Applicants: KABUSHIKI KAISHA TOSHIBA, TOSHIBA INDUSTRIAL PRODUCTS MANUFACTURING CORP.Inventors: Norio TAKAHASHI, Kazuto Sakai, Masanori Arata, Yutaka Hashiba, Wataru Ito, Motoyasu Mochizuki, Mikio Takabatake, Masakatsu Matsubara, Takashi Hanai
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Publication number: 20070052313Abstract: Included are a ring-shaped stator and a ring-shaped rotor arranged inside the stator; the stator includes a stator core with armature windings; the rotor includes a rotor core in which a plurality of permanent magnets are inserted and cooling holes are formed, a coolant flowing in each of the cooling holes; and each of the cooling holes is formed so as to have a sectional view which is a convex toward the outer periphery thereof.Type: ApplicationFiled: July 27, 2006Publication date: March 8, 2007Inventors: Norio Takahashi, Kazuto Sakai, Yoshio Hashidate, Masanori Arata, Wataru Ito, Masakatsu Matsubara, Takashi Hanai, Yasuo Hirano
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Patent number: 6803692Abstract: The permanent magnet type reluctance electric motor includes a stator including a stator iron core and having armature coils placed inside slots, and a rotor provided with a plurality of magnetic barriers formed by cavities and placed on an inner side of the stator such that sections where a magnetic flux can easily pass (d-axis) and sections where a magnetic flux cannot easily pass (q-axis) are alternately formed, and made of a rotor iron core having permanent magnets in cavities. The rotor satisfies a relationship of PL/2&pgr;RWqave≧130, where Wqave [m] indicates an average thickness of the rotor iron core on an outer side in a radial direction of the rotor with respect to cavities arranged in a q-axis direction, L [m]; a width in a circumferential direction of the cavities, P; the number of poles and R [m]; the radius of the rotor.Type: GrantFiled: January 24, 2002Date of Patent: October 12, 2004Assignee: Kabushiki Kaisha ToshibaInventors: Tomoyuki Hattori, Kazuto Sakai, Masanori Arata
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Patent number: 6794784Abstract: Permanent magnets are arranged to be supported by the provision of permanent magnet position-locating projections (12) in permanent magnet embedding holes (5). By optimizing the shape of thin-wall regions (18) and (19) within rotor core (4), leakage of flux generated from the permanent magnets is reduced and the strength of the thin-wall regions where stress is concentrated is ensured.Type: GrantFiled: May 24, 2001Date of Patent: September 21, 2004Assignees: Kabushiki Kaisha Toshiba, Toshiba Industrial Products Manufacturing CorporationInventors: Norio Takahashi, Yutaka Hashiba, Kazuto Sakai, Masanori Arata, Yukihiko Kazao, Takashi Araki, Masakatsu Matsubara, Yasuo Hirano
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Patent number: 6552462Abstract: A reluctance type rotating machine includes a stator 1 having armature windings 2 arranged on an inner periphery of the stator 1, a rotor 3 having a magnetic unevenness in the circumferential direction and a plurality of permanent magnets 6 arranged for negating the armature windings' flux passing between adjoining poles. Each magnet 6 is magnetized in a direction different from a direction to facilitate the rotor's magnetization. A magnetic portion 7 is provided between the pole and the interpole of the rotor 3. Owing to the provision of the magnetic portion 7, when the armature windings are not excited, more than 30% of the permanent magnets' flux is distributed in the rotor 3. Similarly, when the machine is loaded, the permanent magnets' interlinkage flux is more than 10% of composite interlinkage flux composed of armature current and the permanent magnets.Type: GrantFiled: June 4, 2001Date of Patent: April 22, 2003Assignee: Kabushiki Kaisha ToshibaInventors: Kazuto Sakai, Masanori Arata, Mikio Takabatake, Yoshio Hashidate, Ryoichi Kurosawa, Yosuke Nakazawa, Tadashi Tokumasu
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Publication number: 20020109429Abstract: The permanent magnet type reluctance electric motor includes a stator including a stator iron core and having armature coils placed inside slots, and a rotor provided with a plurality of magnetic barriers formed by cavities and placed on an inner side of the stator such that sections where a magnetic flux can easily pass (d-axis) and sections where a magnetic flux cannot easily pass (q-axis) are alternately formed, and made of a rotor iron core having permanent magnets in cavities. The rotor satisfies a relationship of PL/2&pgr;RWqave≧130, where Wqave [m] indicates an average thickness of the rotor iron core on an outer side in a radial direction of the rotor with respect to cavities arranged in a q-axis direction, L [m]; a width in a circumferential direction of the cavities, P; the number of poles and R [m]; the radius of the rotor.Type: ApplicationFiled: January 24, 2002Publication date: August 15, 2002Inventors: Tomoyuki Hattori, Kazuto Sakai, Masanori Arata
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Publication number: 20020047436Abstract: A reluctance type rotating machine includes a stator 1 having armature windings 2 arranged on an inner periphery of the stator 1, a rotor 3 having a magnetic unevenness in the circumferential direction and a plurality of permanent magnets 6 arranged for negating the armature windings' flux passing between adjoining poles. Each magnet 6 is magnetized in a direction different from a direction to facilitate the rotor's magnetization. A magnetic portion 7 is provided between the pole and the interpole of the rotor 3. Owing to the provision of the magnetic portion 7, when the armature windings are not excited, more than 30% of the permanent magnets' flux is distributed in the rotor 3. Similarly, when the machine is loaded, the permanent magnets' interlinkage flux is more than 10% of composite interlinkage flux composed of armature current and the permanent magnets.Type: ApplicationFiled: June 4, 2001Publication date: April 25, 2002Inventors: Kazuto Sakai, Masanori Arata, Mikio Takabatake, Yoshio Hashidate, Ryoichi Kurosawa, Yosuke Nakazawa, Tadashi Tokumasu
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Publication number: 20020047435Abstract: Permanent magnets are arranged to be supported by the provision of permanent magnet position-locating projections (12) in permanent magnet embedding holes (5). By optimizing the shape of thin-wall regions (18) and (19) within rotor core (4), leakage of flux generated from the permanent magnets is reduced and the strength of the thin-wall regions where stress is concentrated is ensured.Type: ApplicationFiled: May 24, 2001Publication date: April 25, 2002Inventors: Norio Takahashi, Yutaka Hashiba, Kazuto Sakai, Masanori Arata, Yukihiko Kazao, Takashi Araki, Masakatsu Matsubara, Yasuo Hirano
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Patent number: 6342745Abstract: A reluctance type rotating machine includes a stator 1 having armature windings 2 arranged on an inner periphery of the stator 1, a rotor 3 having a magnetic unevenness in the circumferential direction and a plurality of permanent magnets 6 arranged for negating the armature windings' flux passing between adjoining poles. Each magnet 6 is magnetized in a direction different from a direction to facilitate the rotor's magnetization. A magnetic portion 7 is provided between the pole and the interpole of the rotor 3. Owing to the provision of the magnetic portion 7, when the armature windings are not excited, more than 30% of the permanent magnets' flux is distributed in the rotor 3 Similarly, when the machine is loaded, the permanent magnets' interlinkage flux is more than 10% of composite interlinkage flux composed of armature current and the permanent magnets.Type: GrantFiled: September 13, 2000Date of Patent: January 29, 2002Assignee: Kabushiki Kaisha ToshibaInventors: Kazuto Sakai, Masanori Arata, Mikio Takabatake, Yoshio Hashidate, Ryoichi Kurosawa, Yosuke Nakazawa, Tadashi Tokumasu
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Patent number: 6329734Abstract: A permanent magnet-reluctance type rotating machine includes an annular stator having armature windings arranged on an inner periphery of the stator, a rotor rotatably arranged inside the stator and a plurality of permanent magnets disposed in a rotor core. One permanent magnet defining each pole is divided into two magnet pieces in a direction parallel to the magnetizing direction of the permanent magnets. Owing to the division of the magnet, the mass of each permanent magnet becomes small in comparison with that of the conventional machine, so that the centrifugal force applied on the magnet holes can be reduced. Consequently, the stress generating in the rotor core is decreased to allow the rotating machine to rotate at a higher speed.Type: GrantFiled: February 22, 2000Date of Patent: December 11, 2001Assignee: Kabushiki Kaisha ToshibaInventors: Norio Takahashi, Kazuto Sakai, Yutaka Hashiba, Masanori Arata, Hirotsugu Tsutsui
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Patent number: 6274960Abstract: A reluctance type rotating machine includes a stator 1 having armature windings 2 arranged on an inner periphery of the stator 1, a rotor 3 having a magnetic unevenness in the circumferential direction and a plurality of permanent magnets 6 arranged for negating the armature windings' flux passing between adjoining poles. Each magnet 6 is magnetized in a direction different from a direction to facilitate the rotor's magnetization. A magnetic portion 7 is provided between the pole and the interpole of the rotor 3. Owing to the provision of the magnetic portion 7, when the armature windings are not excited, more than 30% of the permanent magnets' flux is distributed in the rotor 3. Similarly, when the machine is loaded, the permanent magnets' interlinkage flux is more than 10% of composite interlinkage flux composed of armature current and the permanent magnets.Type: GrantFiled: September 28, 1999Date of Patent: August 14, 2001Assignee: Kabushiki Kaisha ToshibaInventors: Kazuto Sakai, Masanori Arata, Mikio Takabatake, Yoshio Hashidate, Ryoichi Kurosawa, Yosuke Nakazawa, Tadashi Tokumasu
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Patent number: 6268677Abstract: A rotor is provided for a permanent magnet type rotating machine having a stator 1 with armature windings 11. The rotor 3 includes a rotor core 31 and a plurality of permanent magnets 32 arranged in the rotor core 31 so as to negate magnetic flux of the armature windings 11 passing through interpoles 3b. The rotor 3 is constructed so that the average of magnetic flux in an air gap 2 between the rotor 3 and the stator 1, which is produced by the permanent magnets 32 at the armature windings' de-energized, ranges from 0.1 [T] to 0.7 [T] and the ratio (Lq/Ld) of self-inductance of the magnetic portion in a hard-magnetizing direction (q-axis) to self-inductance in an easy-magnetizing direction (d-axis) under a rated load condition ranges from 0.1 to 0.8. Under these conditions, it is possible to realize the rotating machine which operates as an induction machine at the machine's starting and also operates as an synchronous machine at the rated driving due to smooth pull-in.Type: GrantFiled: March 29, 2000Date of Patent: July 31, 2001Assignee: Kabushiki Kaisha ToshibaInventors: Mikio Takabatake, Masanori Arata, Kazuto Sakai, Yutaka Hashiba, Yoshio Hashidate, Norio Takahashi, Koji Oishi, Shiro Amemori
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Patent number: 6265801Abstract: A permanent magnet electrical rotating machine wherein the slots of stator core 2A of stator 1A are rectangular enclosed slots 4A in which triangular projecting gaps 3a are formed on the inner periphery side of this stator core 2A. The stator core 2A is cooled by passing gas through the projecting gaps 3a. The magnet flux that reaches stator core 2A from permanent magnets 6 by passing through retaining ring 8 and air gap 9 is caused to pass the inner periphery sides of the projecting gaps a of the stator core 2A. By this means, oscillation of magnetic flux density in the peripheral direction is prevented, eddy currents in the retaining ring 8 which accompany this oscillation are reduced and temperature rise prevented.Type: GrantFiled: January 22, 1999Date of Patent: July 24, 2001Assignee: Kabushiki Kaisha ToshibaInventors: Yutaka Hashiba, Tadashi Tokumasu, Kazuto Sakai, Norio Takahashi
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Patent number: 6087751Abstract: A reluctance type rotating machine includes a stator having armature windings arranged on an inner periphery of the stator, a rotor having projection portion forming magnetic poles, and a plurality of permanent magnets arranged on both side faces of the projection portions. Owing to the provision of the permanent magnets, it is possible to restrain magnetic fluxes of the armature windings of the stator from leaking toward interpole portions between the magnetic poles. The power output of the machine can be improved by increased effective fluxes.Type: GrantFiled: June 15, 1998Date of Patent: July 11, 2000Assignee: Kabushiki Kaisha ToshibaInventor: Kazuto Sakai
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Patent number: 5808392Abstract: A permanent magnet type rotating machine includes a stator core provided on an inner periphery thereof with armature windings, a rotor core, a plurality of permanent magnets arranged on an outer periphery of the rotor core, and a magnetic ring arranged between the permanent magnets and a stator. The magnetic flux running from the permanent magnets to the stator core through a gap, can be increased by a reduction in magnetic reluctance due to the magnetic ring inserted between the gap and the permanent magnets. The magnetic ring is fitted on either one of the outer peripheries of the permanent magnets and the inner periphery of the stator core.Type: GrantFiled: April 27, 1995Date of Patent: September 15, 1998Assignee: Kabushiki Kaisha ToshibaInventors: Kazuto Sakai, Yutaka Tabuchi
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Patent number: 5619087Abstract: An axial-gap rotary-electric machine which can rotate at a very high speed and can generate a large output and in which a gap is formed extending in the axial direction of the shaft. The rotary-electric machine comprises a rotor (12) and a stator (11). The rotor comprises a plurality of discs members (24-1, 24-2) made of fiber-reinforced plastic or nonmagnetic metal, and a plurality of groups (25) of permanent magnets embedded in said disc members (24-1, 24-2), forming a plurality of magnetic poles on said disc members (24-1, 24-2). Each of the groups (25) consists of a plurality of permanent magnets (25a). The stator (11) includes a casing (11A) and a first stator winding (16B). The casing (11A) comprises a frame (13), brackets (14-1, 14-2), back yokes (15-1, 15-2), and at least one second stator winding (16A-1, 16A-2) divided into a plurality of units in a radial direction.Type: GrantFiled: November 8, 1993Date of Patent: April 8, 1997Assignee: Kabushiki Kaisha ToshibaInventor: Kazuto Sakai