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).
-
Patent number: 8334667Abstract: A permanent magnet rotating electrical machine capable of conducting a variable speed operation at high output in a wide range from low speed to high speed and improving efficiency and reliability in a wide operating range. Two kinds of permanent magnets having different shapes or different magnetic characteristics are embedded in a rotor core, to form a magnetic pole. The permanent magnets arranged at the magnetic pole include a permanent magnet whose product of coercive force and thickness along a magnetizing direction is small and a permanent magnet whose product of coercive force and thickness along the magnetizing direction is large. A magnetic field created by passing a current to an armature coil for a short time is used to irreversibly magnetize the permanent magnet whose product of coercive force and thickness along magnetizing direction is small, thereby changing a total linkage flux amount, and a positive d-axis current is passed when torque is large.Type: GrantFiled: December 7, 2007Date of Patent: December 18, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Kazuto Sakai, Kazuaki Yuuki
-
Patent number: 8330404Abstract: The present invention provides a permanent-magnet-type rotating electrical machine capable of realizing variable-speed operation in a wide range from low speed to high speed at high output and improving, in a wide operating range, efficiency, reliability, and productivity. A narrow magnetic path 11 is formed in a rotor core 2 of a rotor 1 at an inter-pole yoke that magnetically connects adjacent pole core portions 7 to each other, so that the narrow magnetic path is magnetically saturated with flux of a magnetic field created by a predetermined magnetizing current passed to an armature coil 21. Each of first permanent magnets 3 at each of the pole core portions 7 is magnetized with a magnetic field created by a magnetizing current passed to the armature coil 21, to irreversibly change the flux amount of the first permanent magnet.Type: GrantFiled: February 16, 2009Date of Patent: December 11, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Kazuto Sakai, Kazuaki Yuuki
-
Patent number: 8269390Abstract: A permanent-magnet-type rotating electrical machine capable of realizing variable-speed operation in a wide range from low speed to high speed at high output and improving, in a wide operating range, efficiency, reliability, and productivity. The rotating electrical machine includes a first permanent magnet whose product of coercive force and magnetizing direction thickness is small and a second permanent magnet whose product of coercive force and magnetizing direction thickness is large, to form a magnetic pole. The product of coercive force and magnetizing direction thickness of the first permanent magnet is equal to or larger than the product of magnetic field strength and magnetizing direction thickness of the second permanent magnet at a no-load operating point. At the magnetic pole, a magnetic field created by a current of an armature coil magnetizes the first permanent magnet, irreversibly changing a flux amount of the first permanent magnet.Type: GrantFiled: February 16, 2009Date of Patent: September 18, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Kazuto Sakai, Kazuaki Yuuki
-
Publication number: 20120217833Abstract: According to one embodiment, a permanent-magnet type electric rotating machine has a stator, a magnetizing coil, a rotor and a case. The stator has an armature coil configured to form a magnetic circuit for driving. The magnetizing coil is configured to form a magnetic circuit for magnetizing. The rotor has a constant magnetized magnet, a rotor core and a variable magnetized magnet. The rotor core holds the constant magnetized magnet. The constant magnetized magnet is arranged closer to the magnetic circuit for driving than the variable magnetized magnet. The variable magnetized magnet is arranged closer to the magnetic circuit for magnetizing than the constant magnetized magnet.Type: ApplicationFiled: February 23, 2012Publication date: August 30, 2012Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Kazuto SAKAI, Yutaka HASHIBA, Norio TAKKAHASHI, Kazuaki YUUKI, Makoto MATSUSHITA, Daisuke MISU, Masanori ARATA, Tadashi TOKUMASU, Motoyasu MOCHIZUKI, Kuniyuki ARAKI
-
Publication number: 20120181970Abstract: 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: March 20, 2012Publication date: July 19, 2012Applicant: Kabushiki Kaisha ToshibaInventors: Kazuaki Yuuki, Kazuto Sakai, Hiroshi Mochikawa
-
Patent number: 8179068Abstract: 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: GrantFiled: July 24, 2007Date of Patent: May 15, 2012Assignee: Kabushiki Kaisha ToshibaInventors: Kazuaki Yuuki, Kazuto Sakai, Hiroshi Mochikawa
-
Publication number: 20120091848Abstract: An increase of the magnetization current can be prevented during demagnetization and magnetization, and a variable speed operation can be achieved at a high power output over a wide range of from a low speed to a high speed. A rotor (1) is configured by a rotor core (2), a variable magnetic force magnet (3) and a fixed magnetic force magnet (4). A variable magnetic force magnet (3) and a fixed magnetic force magnet (4a) are overlapped in the magnetization direction thereof to form a series of magnets. The series of magnets is located within the rotor core at a position where the magnetization direction is in the direction of a d-axis. On either side of the series of magnets of the variable magnetic force magnet (3) and the fixed magnetic force magnet (4a), fixed magnetic force magnets (4b, 4b) are located at a position where the magnetization direction is in the direction of the d-axis.Type: ApplicationFiled: November 19, 2009Publication date: April 19, 2012Applicant: Kabushkiki Kaisha ToshibaInventors: Kazuto Sakai, Yutaka Hashiba, Norio Takahashi, Kazuaki Yuuki
-
Publication number: 20110309706Abstract: According to one embodiment, a rotor 1 has rotor cores 2a, 2b divided in the axial direction. a permanent magnet 30 is mounted at the position of each of the magnetic poles of cores. The permanent magnet 30 of each magnetic pole is configured by a single tabular member that penetrates the two divided cores in the axial direction. Convex parts 31a, 31b are respectively provided on the outer peripheries of the respective magnetic poles of the rotor cores along the axial direction of the rotor. The convex parts 31a, 31b are provided to positions that are displaced for each of the two divided cores. The magnetic flux density increases in the convex parts, which becomes the magnetic pole center. Since the convex parts positions are displaced to each other, a skew function can be exhibited even if the permanent magnet is mounted at the same position.Type: ApplicationFiled: December 16, 2009Publication date: December 22, 2011Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Norio Takahashi, Kazuto Sakai, Yutaka Hashiba, Kazuaki Yuuki, Masanori Arata, Yusuke Matsuoka, Tadashi Tokumasu
-
Publication number: 20110304235Abstract: According to one embodiment, a rotor is configured by a rotor core and magnetic poles. Two or more types of permanent magnets are used such that each product of coercivity and thickness in the magnetization direction becomes different. A stator is located outside the rotor with air gap therebetween and configured by an armature core winding. At least one permanent magnet is magnetized by a magnetic field by a current of the armature winding to change a magnetic flux content thereof irreversibly. A short circuited coil is provided to surround a magnetic path portion of the other permanent magnet excluding the magnet changed irreversibly and a portion adjacent to the other permanent magnet where the magnetic flux leaks. A short-circuit current is generated in the short circuited coil by the magnetic flux generated by conducting a magnetization current to the winding. A magnetic field is generated by the short-circuit current.Type: ApplicationFiled: December 15, 2009Publication date: December 15, 2011Applicant: Kabushiki Kaisha ToshibaInventors: Yutaka Hashiba, Kazuto Sakai, Norio Takahashi, Kazuaki Yuuki, Masanori Arata, Yusuke Matsuoka, Motoyasu Mochizuki, Tadashi Tokumasu
-
Patent number: 8044548Abstract: 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: GrantFiled: August 23, 2006Date of Patent: October 25, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Kazuto Sakai, Masanori Arata
-
Patent number: 8030817Abstract: A rotor of a permanent-magnet-type rotating electrical machine of the present invention has a plurality of magnetic poles in point symmetry with respect to a rotation center of a rotor core 2. For each of the magnetic poles, there are arranged a permanent magnet 3 whose product of a coercive force and a magnetizing direction thickness is small and a permanent magnet 4 whose product of a coercive force and a magnetizing direction thickness is large. The permanent magnet 3 whose product of a coercive force and a magnetizing direction thickness is small is irreversibly magnetized by a magnetic field created by a current of an armature coil 21, to change a total linkage flux amount. This realizes a wide-range variable-speed operation of high output, to provide the rotating electrical machine with a wide operating range and high efficiency.Type: GrantFiled: August 2, 2007Date of Patent: October 4, 2011Assignee: Kabushiki Kaisha ToshibaInventors: Kazuto Sakai, Masanori Arata
-
Publication number: 20110175478Abstract: An increase of the magnetization current can be restrained during demagnetization and magnetization, and a variable speed operation can be achieved at a high power output over a wide range of from a low speed to a high speed. A rotor 1 is configured by a rotor core 2, permanent magnets 3 having a small value as the product of the coercivity and the thickness in the magnetization direction thereof, and permanent magnets 4 having a large value as the product. When reducing a flux linkage of the permanent magnets 3, a magnetic field directed to the reverse direction of the magnetization direction of the permanent magnets 3 due to a current of an armature coil is caused to act on them. When increasing a flux linkage of the permanent magnets 3, a magnetic field directed to the same direction as the magnetization direction of the permanent magnets 3 due to a current of an armature coil is caused to act on them.Type: ApplicationFiled: June 19, 2009Publication date: July 21, 2011Applicant: Kabushiki Kaisha ToshibaInventors: Kazuto Sakai, Yutaka Hashiba, Yosuke Otsubo, Yusuke Matsuoka, Norio Takahashi, Tadashi Tokumasu
-
Publication number: 20100327787Abstract: The present invention provides a permanent-magnet-type rotating electrical machine capable of realizing variable-speed operation in a wide range from low speed to high speed at high output and improving, in a wide operating range, efficiency, reliability, and productivity. A narrow magnetic path 11 is formed in a rotor core 2 of a rotor 1 at an inter-pole yoke that magnetically connects adjacent pole core portions 7 to each other, so that the narrow magnetic path is magnetically saturated with flux of a magnetic field created by a predetermined magnetizing current passed to an armature coil 21. Each of first permanent magnets 3 at each of the pole core portions 7 is magnetized with a magnetic field created by a magnetizing current passed to the armature coil 21, to irreversibly change the flux amount of the first permanent magnet.Type: ApplicationFiled: February 16, 2009Publication date: December 30, 2010Applicant: Kabushiki Kaisha ToshibaInventors: Kazuto Sakai, Kazuaki Yuuki
-
Publication number: 20100327689Abstract: A permanent-magnet-type rotating electrical machine capable of realizing variable-speed operation in a wide range from low speed to high speed at high output and improving, in a wide operating range, efficiency, reliability, and productivity. The rotating electrical machine includes a first permanent magnet whose product of coercive force and magnetizing direction thickness is small and a second permanent magnet whose product of coercive force and magnetizing direction thickness is large, to form a magnetic pole. The product of coercive force and magnetizing direction thickness of the first permanent magnet is equal to or larger than the product of magnetic field strength and magnetizing direction thickness of the second permanent magnet at a no-load operating point. At the magnetic pole, a magnetic field created by a current of an armature coil magnetizes the first permanent magnet, irreversibly changing a flux amount of the first permanent magnet.Type: ApplicationFiled: February 16, 2009Publication date: December 30, 2010Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Kazuto Sakai, Kazuaki Yuuki
-
Publication number: 20100301697Abstract: A rotor for a rotating electrical machine suppresses demagnetization of permanent magnets without deteriorating motor characteristics, is low-cost, and is highly reliable. The rotor has a plurality of rotor cores (2) that are stacked together, a plurality of permanent magnets (6a, 6b) axially divided by the rotor cores (2) and circumferentially arranged on each of the rotor cores (2), to circumferentially form magnetic irregularities, and a rotor blank (14a) made of nonmagnetic material arranged between those of the rotor cores (2) that are adjacent to each other.Type: ApplicationFiled: November 25, 2008Publication date: December 2, 2010Applicants: Kabushiki Kaisha Toshiba, Toshiba Industrial Products Manufacturing Corp.Inventors: Norio Takahashi, Mikio Takabatake, Masanori Arata, Kazuto Sakai, Yutaka Hashiba, Wataru Ito, Tadashi Tokumasu, Masakatsu Matsubara
-
Patent number: 7804216Abstract: 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 unevenness. 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 a radius of the rotor, and P is the number of poles.Type: GrantFiled: October 19, 2007Date of Patent: September 28, 2010Assignees: Kabushiki Kaisha Toshiba, Toshiba Industrial Products Manufacturing CorporationInventors: Norio Takahashi, Kazuto Sakai, Masanori Arata, Yutaka Hashiba, Wataru Ito, Motoyasu Mochizuki, Mikio Takabatake, Masakatsu Matsubara, Takashi Hanai
-
Publication number: 20100201294Abstract: A variable magnetic flux motor drive system includes: a variable magnetic flux motor having a variable magnet which is a low-coercive permanent magnet; an inverter that drives the variable magnetic flux motor 1; an inverter as a magnetization unit which supplies a magnetization current for controlling a magnetic flux of the variable magnet; and a boosting unit boosting an input DC voltage to a predetermined target value to output it to the inverter. The variable magnetic flux motor drive system makes it possible to achieve size reduction and high efficiency, while securing a voltage required for supplying a magnetization current when controlling the magnetic flux of the variable magnet.Type: ApplicationFiled: September 16, 2008Publication date: August 12, 2010Applicant: Kabushiki Kaisha ToshibaInventors: Kazuaki Yuuki, Kazuto Sakai, Hiroshi Mochikawa
-
Publication number: 20100171385Abstract: A rotor of a permanent-magnet-type rotating electrical machine of the present invention has a plurality of magnetic poles in point symmetry with respect to a rotation center of a rotor core 2. For each of the magnetic poles, there are arranged a permanent magnet 3 whose product of a coercive force and a magnetizing direction thickness is small and a permanent magnet 4 whose product of a coercive force and a magnetizing direction thickness is large. The permanent magnet 3 whose product of a coercive force and a magnetizing direction thickness is small is irreversibly magnetized by a magnetic field created by a current of an armature coil 21, to change a total linkage flux amount. This realizes a wide-range variable-speed operation of high output, to provide the rotating electrical machine with a wide operating range and high efficiency.Type: ApplicationFiled: August 2, 2007Publication date: July 8, 2010Applicant: Kabushiki Kaisha ToshibaInventors: Kazuto Sakai, Masanori Arata
-
Patent number: 7705503Abstract: 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: GrantFiled: July 27, 2006Date of Patent: April 27, 2010Assignees: Kabushiki Kaisha Toshiba, Toshiba Industrial Products Manufacturing CorporationInventors: Norio Takahashi, Kazuto Sakai, Yoshio Hashidate, Masanori Arata, Wataru Ito, Masakatsu Matsubara, Takashi Hanai, Yasuo Hirano
-
Publication number: 20100060223Abstract: A permanent magnet rotating electrical machine capable of conducting a variable speed operation at high output in a wide range from low speed to high speed and improving efficiency and reliability in a wide operating range. Two kinds of permanent magnets having different shapes or different magnetic characteristics are embedded in a rotor core, to form a magnetic pole. The permanent magnets arranged at the magnetic pole include a permanent magnet whose product of coercive force and thickness along a magnetizing direction is small and the permanent magnet whose product of coercive force and thickness along the magnetizing direction is large. A magnetic field created by passing a current to an armature coil for a short time is used to irreversibly magnetize the permanent magnet whose product of coercive force and thickness along magnetizing direction is small, thereby changing a total linkage flux amount, and a positive d-axis current is passed when torque is large.Type: ApplicationFiled: December 7, 2007Publication date: March 11, 2010Applicant: Kabushiki Kaisha ToshibaInventors: Kazuto Sakai, Kazuaki Yuuki