Embedded Patents (Class 310/156.56)
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Publication number: 20090184597Abstract: A BLDC motor is provided. The BLDC motor includes a stator having a plurality of teeth formed at an inside thereof, a plurality of coils, each of the plurality of coils being wound around a corresponding tooth of the stator, a rotor located at the inside of the stator, a plurality of magnets located at an edge portion of the rotor, a plurality of magnet placement portions located on the rotor, each magnet placement portion having a first and second barrier formed at opposite ends of the magnet placement portion, the first barrier and second barrier of adjacent magnet placement portions being separated by a gap portion, each of the plurality of magnets being inserted into a corresponding magnet placement portion, and at least one of the gap portions includes a third barrier located therein. A rotor and fan motor including a plurality of barriers formed on the rotor are also provided.Type: ApplicationFiled: January 16, 2009Publication date: July 23, 2009Inventor: Kyung Hoon Lee
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Patent number: 7560842Abstract: A rotor core is provided with a plurality of slits extending in the rotation shaft direction, independently of openings. The first slit is arranged at the center of the magnetic pole of the rotor core to be capable of absorbing stress acting on an inner circumferential surface of each opening in a direction normal to a main surface of a permanent magnet. The second slit is arranged between the magnetic poles of the rotor core to be capable of absorbing stress acting in parallel with the main surface of the permanent magnet. Thus, the rotor core is prevented from deforming in a radial outward direction. Further, by forming the first and second slits each in a form not interfering the magnetic path of the magnetic flux by the stator passing inside the rotor core, the motor performance is ensured.Type: GrantFiled: August 1, 2006Date of Patent: July 14, 2009Assignee: Toyota Jidosha Kabushiki KaishaInventor: Hiroyuki Hattori
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Patent number: 7550891Abstract: A permanent-magnet motor including a rotor having permanent magnets disposed therein, and a stator, wherein an outer circumferential surface of the rotor is opposite to an inner circumferential surface of the stator, and one or both of the outer circumferential surface of the rotor and the inner circumferential surface of the stator are varied in a radial direction so as to provide a non-uniform gap between the two surfaces to approximate sinusoidal change in magnetic flux.Type: GrantFiled: January 5, 2006Date of Patent: June 23, 2009Assignee: Samsung Electronics Co., Ltd.Inventor: Young Kyoun Kim
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Patent number: 7550889Abstract: An interior permanent magnet electric motor. A lobed rotor comprising composite slots and non-composite slots radially spaced from its longitudinal axis of rotation extending parallel to the axis. Ferrite magnets are positioned in both the composite and non-composite slots and neo magnets are positioned in the composite slots only.Type: GrantFiled: November 30, 2006Date of Patent: June 23, 2009Assignee: Emerson Electric Co.Inventor: Gary E. Horst
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Publication number: 20090152972Abstract: In the present invention, since gaps respectively provided at one ends of a field magnet through-hole respectively extend toward the other ends passing on the side of a periphery with respect to the field magnet through-hole, the radial dimension of the magnetic member in this portion can be made smaller than the center of magnetic poles, so that the difference in thickness of the magnetic member in the radial direction between the border of magnetic poles and the magnetic poles can be reduced. Accordingly, the asymmetry of the configuration of a rotor is not absolutely necessary, and the outer surface does not need to be depressed for reducing the torque ripple.Type: ApplicationFiled: February 1, 2006Publication date: June 18, 2009Applicant: Daikin Industries, Ltd.Inventor: Kiyotaka Nishijima
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Patent number: 7535148Abstract: An electromagnetic generator comprising a multilayer assembly of a first layer carrying at least one magnet, a second layer carrying at least one coil, and a third layer carrying at least one magnet, the at least one magnet of the first and third layers being configured to define therebetween a region of magnetic flux in which the at least one coil is disposed, at least one of the layers being shaped to define a respective displaceable portion thereof which is displaceable by vibration of the electromagnetic generator thereby to cause relative movement between the coil and the magnets and generate an electrical current in the coil.Type: GrantFiled: August 13, 2004Date of Patent: May 19, 2009Assignee: University of SouthamptonInventors: Nicholas Robert Harris, Michael John Tudor, Neil Maurice White, Stephen Paul Beeby, Peter Glynne-Jones
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Patent number: 7531934Abstract: In a method of manufacturing a self-start synchronous motor for preventing deterioration of permanent magnets used in a rotor, and also for enhancing the efficiency of the self-start synchronous motor, the self-start synchronous motor comprising a stator having a stator core and windings wound around the stator core, and a rotor having an outer diameter slightly smaller than an inner diameter of the stator and arranged inside of the stator. The rotor is provided with a rotor core, a plurality of conductor bars embedded in the outer peripheral portion of the rotor core over an entire periphery thereof, end rings provided on opposite end sides of the conductor bars and constituting a squirrel cage conductor in cooperation with the conductor bars, and a plurality of permanent magnets embedded in the rotor core and arranged at a position inner than that of an inner peripheral surface of the conductor bars.Type: GrantFiled: May 25, 2006Date of Patent: May 12, 2009Assignee: Hitachi Appliances, Inc.Inventors: Baiying Hang, Tomio Yoshikawa, Yasuro Ohishi, Akeshi Takahashi, Haruo Koharagi
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Patent number: 7521832Abstract: A permanent magnet rotating electric machine comprises a stator having stator windings wound round a stator iron core and a permanent magnet rotor having a plurality of inserted permanent magnets in which the polarity is alternately arranged in the peripheral direction in the rotor iron core. The rotor iron core of the permanent magnets is composed of magnetic pole pieces, auxiliary magnetic poles, and a stator yoke, and furthermore has concavities formed on the air gap face of the magnetic pole pieces of the rotor iron core of the permanent magnets, gently tilting from the central part of the magnetic poles to the end thereof. In a permanent magnet rotating electric machine, effects of iron loss are reduced, and an electric car using highly efficient permanent magnet rotating electric machine are realized.Type: GrantFiled: December 15, 2006Date of Patent: April 21, 2009Assignee: Hitachi, Ltd.Inventors: Fumio Tajima, Yutaka Matsunobu, Masashi Kitamura, Noriaki Hino, Takashi Kobayashi, Shigeru Kakugawa, Takashi Yasuhara
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Patent number: 7518278Abstract: A method and apparatus in which a rotor (11) and a stator (17) define a radial air gap (20) for receiving AC flux and at least one DC excitation coil (23, 24) positioned near the stator end turn to produce DC flux in axial air gaps (21, 22) additive to the AC flux. Side magnets (16) and flux-guiding magnets (14) are provided as boundaries separating the side poles (12a, 12b) of opposite polarity from other portions of the rotor (11) and from each other to define PM poles (12a, 12b) for conveying the DC flux to or from the primary air gap (20) and for inhibiting flux from leaking from said pole portions prior to reaching the primary air gap (20). Side magnets (16), side poles (12a and 12b), flux-guiding magnets (14), ferromagnetic end plates (11c), non-magnetic end plates (12c), and ring bands (37) are optionally provided for performance improvement.Type: GrantFiled: September 21, 2005Date of Patent: April 14, 2009Assignee: UT-Battelle, LLCInventor: John S. Hsu
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Patent number: 7498708Abstract: A rotor includes a rotor core formed of webs defining a layout of the magnets in the rotor core. The rotor core has at least one layer of magnets forming a plurality of poles. Each pole includes a plurality of slots for holding a magnet, at least two ribs comprising web portions between the centerline slot and each wing slot, and a plurality of magnets arranged in corresponding slots. The slots have at least a centerline slot and two angled wing slots extending from a position at or around respective ends of the centerline slot towards an outer circumference of the rotor core. The wing slots may taper from a position at or around respective ends of the centerline slot towards an outer circumference of the rotor core.Type: GrantFiled: October 26, 2005Date of Patent: March 3, 2009Assignee: Kollmorgen CorporationInventors: Gerald Brown, Ron Bishop
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Publication number: 20090045689Abstract: A rotor includes: a rotor core fixedly attached to a rotational shaft and having a magnet-inserted hole portion; a magnet inserted into the magnet-inserted hole portion; and a resin portion injected into the magnet-inserted hole portion. The rotor core is constructed by axially stacking a plurality of electromagnetic steel sheets. The electromagnetic steel sheets include: an electromagnetic steel sheet having the magnet-inserted hole portion and a weight-reducing-purpose hole portion provided separately from the magnet-inserted hole portion; and an electromagnetic steel sheet located on at least one axial end of the rotor core and having a portion covering the hole portion formed in the electromagnetic steel sheet.Type: ApplicationFiled: March 9, 2007Publication date: February 19, 2009Applicants: TOYOTA JIDOSHA KABUSHIKI KAISHA, MITSUI HIGH-TEC, INCInventors: Kentaro Haruno, Taketo Takeuchi, Katsumi Amano, Takashi Fukumoto, Kazutoshi Ueda
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Patent number: 7474029Abstract: A machine includes a stator and a rotor having a plurality of poles. Each pole is formed at least in part by a plurality of permanent magnets recessed within the rotor at a predetermined distance from an outer surface of the rotor. The distance is predetermined to minimize rotor flux variation near the outer surface during rotation of the rotor relative to the stator. Eddy current losses are thereby reduced.Type: GrantFiled: June 14, 2004Date of Patent: January 6, 2009Assignee: General Motors CorporationInventors: Khwaja M. Rahman, James M. Nagashima
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Publication number: 20080303368Abstract: A permanent magnet machine includes a stator having a hollow core, a rotor rotatably disposed inside the hollow core, and a plurality of multilayered permanent magnets embedded in the rotor. Each multilayered permanent magnet has opposite first and second ends, and includes a first magnet disposed at the first end, and a second magnet disposed at the second end and coupled to the first magnet. The second magnet has higher magnet strength than the first magnet, and also has lower high-temperature stability than the first magnet.Type: ApplicationFiled: June 6, 2007Publication date: December 11, 2008Inventors: Khwaja M. Rahman, Edward L. Kaiser, Matthew D. Laba
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Publication number: 20080296990Abstract: The invention is based on an electrical machine having a rotor rotatably mounted about an axis of rotation and a stator. The rotor has at least one permanent magnet. The rotor has alternating field-focusing and field-free regions in its rotor body which are parallel to the axis of rotation.Type: ApplicationFiled: November 15, 2006Publication date: December 4, 2008Inventor: Steven Andrew Evans
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Patent number: 7459821Abstract: A PMA (Permanent Magnet Assisted) synRM and a method for imposing a magnetic force thereon. Magnets are inserted into outer flux barriers of a plurality of flux barriers formed along the radius of a rotor, and bridges or slim portions are formed on inner flux barriers at positions corresponding to the positions of the magnets so that the magnetic force is imposed on the magnets through coils. Since the number of the flux barriers is sufficiently increased while the amount of the magnets consumed is decreased, the PMA synRM has increased efficiency and reduced production costs.Type: GrantFiled: January 4, 2005Date of Patent: December 2, 2008Assignee: LG Electronics Inc.Inventors: Dal Ho Cheong, Kyung Hoon Lee, Hyun Hun Shin, June Hee Won, Jae Yoon Oh, Gil Su Lee
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Publication number: 20080284271Abstract: The motor includes a cylindrical rotor core, a plurality of magnets axially penetrated in the rotor core, a pair of separation-preventing plates installed at both ends of the rotor core, and at least one fixing member to fix the separation-preventing plates to the rotor core. The fixing member includes a rod portion extending in an axial direction of the rotor core to be disposed on an outer circumferential surface of the rotor core, and supporting portions bent from both ends of the rod portion and used to support the separation-preventing plates. The separation-preventing plates can be fixed to the rotor core by the fixing member disposed on the outer circumferential surface of the rotor core. The fixing member has no risk of hindering the flow of magnetic flux generated from the magnets, resulting in an improvement in the performance of the motor.Type: ApplicationFiled: March 11, 2008Publication date: November 20, 2008Applicant: SAMSUNG ELECTRONICS CO., LTD.Inventors: Hong Jung Kim, Sang Uk Park, Hyung Chul Lee
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Patent number: 7446448Abstract: A magnetic gap is provided between a permanent magnet of a rotor and an auxiliary magnet pole portion which is arranged adjacent to the permanent magnet in a peripheral direction. A gradual change in a magnetic flux density distribution of a surface of the rotor is obtained and a cogging torque and a torque pulsation are restrained. By obtaining a reluctance torque according to the auxiliary magnetic pole, a permanent magnet electric rotating machine in which the cogging torque and the torque pulsation are restrained can be obtained and further an electromotive vehicle having the permanent magnet electric rotating machine can be provided.Type: GrantFiled: August 25, 2006Date of Patent: November 4, 2008Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
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Publication number: 20080252166Abstract: A rotor core of a rotating electrical machine formed by stacking a plurality of blanks blanked from a steel sheet, the blank having a yoke, a magnetic pole portion confronting the yoke, and a magnet insertion hole positioned between the yoke and the magnetic pole portion, the magnetic pole portion having a projection projecting circumferentially at two circumferential sides thereof.Type: ApplicationFiled: April 13, 2005Publication date: October 16, 2008Applicant: KABUSHIKI KAISHA TOSHIBAInventors: Tsuyoshi Shiga, Noboru Shibata
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Patent number: 7432624Abstract: The object of the invention is a rotor (4) for a permanent-magnet electrical machine, comprising an axle (6) mounted to the machine body with bearings, a rotor pack made of iron and arranged around the axle (6), as well as permanent magnets (10) adapted to the rotor pack, used for forming the magnetic poles (9) of the rotor. According to the invention, the rotor poles (9) contain a slot (24) extending from both edges of the pole (9) essentially towards the centre of the pole; the slot (24) is closer to the outer circumference (3) of the rotor than the central axle of the rotor. The invention also includes a method for manufacturing such a rotor.Type: GrantFiled: August 26, 2003Date of Patent: October 7, 2008Assignee: ABB OYInventors: Jere Kolehmainen, Jari Pekola, Jouni Ikaheimo
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Patent number: 7425786Abstract: A permanent magnet type rotating electrical machine that is capable of producing a higher output and is suitable for high-speed rotation. A pair of nonmagnetic portions are formed in a rotor core at opposite ends of each pole. The waveform of induced voltage and a motor voltage are adjusted based on two parameters, i.e., an angle covering minimum magnetic path portions formed by the nonmagnetic portions and a magnet width. Assuming that a circumferential pitch of teeth cores with respect to a rotor axis is ?s (degree) and an opening angle contained by a circumferential width between radial width minimum points of the pair of magnetic path portions with respect to the rotor axis is ? (degree), ??(n+Y)×?s (n: integer larger than 0) is met. Y=0.5 is set when the stator windings are wound in a distributed winding way, and Y=0.9-1.2 is set when they are wound in a concentrated winding way. The magnet forming one pole is divided into two parts, and a bridge portion is formed between the two divided magnet parts.Type: GrantFiled: November 30, 2005Date of Patent: September 16, 2008Assignee: Hitachi, Ltd.Inventors: Noriaki Hino, Yutaka Matsunobu, Fumio Tajima, Takashi Yasuhara
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Patent number: 7417349Abstract: A rotating electric machine comprises a stator having stator salient poles, three-phases windings wound around said stator salient poles, a rotor rotatable held inside the said stator, and permanent magnets inserted into said rotor and positioned opposite to said stator salient poles. The three-phase windings are concentratively wound around each of the stator salient poles, with windings of each phase wound around at more than one stator salient pole. The windings of each phase have a phase difference of voltage between at least one of the windings and the other.Type: GrantFiled: September 26, 2005Date of Patent: August 26, 2008Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.Inventors: Fumio Tajima, Yutaka Matsunobe, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keijiro Oda
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Patent number: 7408280Abstract: A Lundell type rotor core with a pair of side cores and a magnetic-pole cylindrical portion has a structure in which the magnetic-pole cylindrical portion is mated between both the side cores (also referred to as “pole cores”) in a radial direction at an outside of a field coil wound on a boss portion in the side cores. The magnetic-pole cylindrical portion is made of plural magnetic steel sheets laminated in the axis direction, and is easily deformed rather than both the side cores. The easy deformation characteristic of the magnetic-pole cylindrical portion prevents generation of a gap during the assembling process of the magnetic-pole cylindrical portion and the side cores. Without paying strict dimension control of the components for the rotor core, it is easily possible to prevent any generation of a gap between the side cores and the magnetic-pole cylindrical portion while assembling. It is thereby possible to prevent a deterioration of a magnetic flux flowing in the rotor core.Type: GrantFiled: August 8, 2006Date of Patent: August 5, 2008Assignee: Denso CorporationInventor: Tooru Ooiwa
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Patent number: 7405503Abstract: The present invention provides a rotating electric machine in which damage to a magnet from heat is prevented, eddy current loss is reduced while decreasing an eddy current generated in a permanent magnet, and furthermore, time and cost for manufacturing can be reduced.Type: GrantFiled: November 15, 2006Date of Patent: July 29, 2008Assignee: Shin-Etsu Chemical Co., Ltd.Inventor: Yasuaki Aoyama
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Patent number: 7405504Abstract: A rotor for a rotary electric machine includes a rotor core made of magnetic material, and being in the form of a disk, and a plurality of magnet sets each including a pair of permanent magnets whose polarities are identical to each other. The magnet sets are arranged circumferentially in the rotor core so that the polarities of the magnet sets change alternately. The rotor core includes nonmagnetic portions each formed between adjacent two of the magnet sets.Type: GrantFiled: September 13, 2005Date of Patent: July 29, 2008Assignees: Nissan Motor Co., Ltd., National University Corporation Tokyo University of Agriculture and TechnologyInventors: Minoru Arimitsu, Kan Akatsu
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Patent number: 7388310Abstract: The invention relates to a synchronous electric motor comprising a stator (10) and at least one rotor (20) with permanent magnets (21), characterized by an embodiment with Xd>Xq; where Xd is the direct reactance and Xq the quadrature reactance.Type: GrantFiled: March 29, 2004Date of Patent: June 17, 2008Assignee: Moteurs Leroy-SomerInventors: Atef Abou-Akar, Jacques Saint-Michel
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Patent number: 7378774Abstract: A laminated core having a first number of magnetic poles, the first number being a natural number divided by two, of a rotary electric machine, includes a plurality of arc-shaped unit cores each having a second number of magnetic poles, the second number being a natural number except for an aliquot part of the first number. The unit cores are wound and laminated a predetermined number of times in a circumferential direction into a spiral shape in such a manner that an axial lamination amount of the unit cores is obtained by an equation of X=?*t/360, X being the axial lamination amount, ? being a winding angle of the unit cores, and t being a thickness of the unit core. The unit cores are adjacent to each other in the circumferential direction connected to each other at a part of an outer circumference thereof.Type: GrantFiled: August 25, 2006Date of Patent: May 27, 2008Assignee: Aisin Seiki Kabushiki KaishaInventors: Atsushi Torii, Masafumi Sakuma, Akinori Hoshino, Hiroyuki Yamamoto
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Patent number: 7378773Abstract: A magnetic gap is provided between a permanent magnet of a rotor and an auxiliary magnet pole portion which is arranged adjacent to the permanent magnet in a peripheral direction. A gradual change in a magnetic flux density distribution of a surface of the rotor is obtained and a cogging torque and a torque pulsation are restrained. By obtaining a reluctance torque according to the auxiliary magnetic pole, a permanent magnet electric rotating machine in which the cogging torque and the torque pulsation are restrained can be obtained and further an electromotive vehicle having the permanent magnet electric rotating machine can be provided.Type: GrantFiled: August 25, 2006Date of Patent: May 27, 2008Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
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Patent number: 7332845Abstract: A rotor includes a shalt that defines a rotor axis, a first end portion coupled to the shaft, and a pole piece that defines an enclosed aperture therethrough. A second end portion is positioned to dispose the pole piece between the first end portion and the second end portion. A portion of one of the first end portion and the second end portion extends through the aperture and bonds with the other of the first end portion and the second end portion. The portion is integrally-formed as a single piece with one of the first end portion and the second end portion.Type: GrantFiled: November 20, 2006Date of Patent: February 19, 2008Assignee: A. O. Smith CoporationInventors: Robert J. Heideman, Dan M. Ionel
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Publication number: 20070273235Abstract: This electric motor includes first permanent magnets secured integrally to an outer periphery side rotor and second permanent magnets secured integrally to an inner periphery side rotor. The first permanent magnets and the second permanent magnets are arranged so as to offset the relative torque produced between the outer periphery side rotor and the inner periphery side rotor based on the magnetic flux of the inner peripheral permanent magnets and the outer peripheral permanent magnets.Type: ApplicationFiled: May 22, 2007Publication date: November 29, 2007Inventors: Masaaki Kaizuka, Hiromitsu Sato, Hirofumi Atarashi, Shoei Abe
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Publication number: 20070252470Abstract: Disclosed is a rotary device of a generator or motor which includes: a stator having a hollow portion formed at the inside thereof and a plurality of slots formed to wind coils therearound, each of the plurality of slots being skewed at a predetermined angle; a rotor shaft formed of a nonmagnetic material; a cylindrical rotor body adapted to axially rotate together with the rotor shaft; a plurality of N-polar and S-polar permanent magnet groups insertedly coupled radially along the outside of the center portion of the rotor body in an alternating arrangement; a plurality of magnetic flux-increasing magnets insertedly coupled along the inside of the rotor body and arranged on the lines of magnetic force formed by the N-polar and S-polar permanent magnet groups, for increasing magnetic flux; and a rotor adapted to be rotatably inserted into the hollow portion of the stator.Type: ApplicationFiled: April 26, 2007Publication date: November 1, 2007Inventor: SUN-HYU LEE
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Publication number: 20070252468Abstract: Disclosed is a rotor of a generator or motor having an auxiliary coil provided around a rotor body, thereby preventing the distortion of output voltage waveforms according to the variation of load, and thereby allowing the fine adjustment of the output voltages of the generator by the control of the current flowing to the auxiliary coil. The rotor of a generator or motor includes: a rotor body adapted to axially rotate together with a rotor shaft; at least one set of N-polar and S-polar permanent magnet groups arranged along the circumferential direction of the rotor body at predetermined intervals; and a plurality of magnetic flux-increasing elements formed on the lines of magnetic force formed by the N-polar and S-polar permanent magnet groups around one side of the rotor body.Type: ApplicationFiled: April 26, 2007Publication date: November 1, 2007Inventor: SUN-HYU LEE
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Patent number: 7282827Abstract: A permanent magnet motor has permanent-magnet-holding slots 5 formed in those parts of a rotor core 2A which correspond to sides of an approximately regular polygon centered on an axis of the rotor core 2A, permanent magnets 4 inserted in the respective permanent-magnet-holding slots, and four or more radially elongated slits 6 arranged apart from each other along each of the permanent-magnet-holding slots on an outer core outside the permanent-magnet-holding slots, characterized in that at a radially outer end, the slits are spaced approximately equally while at a radially inner end, spacing between the slits is reduced with increasing distance from a center of each permanent magnet, with the spacing at the center being the largest.Type: GrantFiled: July 28, 2004Date of Patent: October 16, 2007Assignee: Kabushiki Kaisha ToshibaInventor: Toshihiko Futami
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Patent number: 7262526Abstract: A rotor for a permanent magnet motor of an outer rotor type having a plurality of permanent magnets and disposed around a stator includes a frame, an annular iron core combined integrally with the frame, and a plurality of insertion holes formed in the core so that the permanent magnets are inserted in the insertion holes respectively. The frame, the core and the permanent magnets are combined integrally with one another by a synthetic resin. Each insertion hole includes a magnet disposing portion in which the permanent magnet is disposed, a space portion located in at least one of circumferential both ends of each permanent magnet disposed in the magnet disposing portion, and a positioning portion positioning each permanent magnet in the magnet disposing portion, and the molten synthetic resin is poured into the space portion.Type: GrantFiled: June 16, 2003Date of Patent: August 28, 2007Assignees: Kabushiki Kaisha Toshiba, Toshiba Ha Products Co., Ltd., Toshiba Consumer Marketing CorporationInventors: Tsuyoshi Shiga, Masami Hattori
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Patent number: 7250703Abstract: A permanent magnet motor includes a rotor core having magnetic pole faces including first to third faces. The first face is formed on a peripherally central part and has a peripherally uniform width of the gap. Each of the second and third faces is formed on both peripheral ends respectively and has a width of a gap rendered larger as each of the second and third faces comes close to a boundary between magnetic poles. The first face ranges from ±15 degrees to ±35 degrees in electrical angle about a center of the magnetic pole and has such a circular arc shape that the gap width is increased by about 10% relative to a minimum gap width.Type: GrantFiled: November 23, 2005Date of Patent: July 31, 2007Assignee: Kabushiki Kaisha ToshibaInventors: Isamu Nitta, Minoru Awazu
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Patent number: 7233089Abstract: A permanent magnet rotating electric machine uses no skewing under a predetermined current and voltage condition to prevent torque from decreasing and to decrease pulsation torque to make the machine less vibrating and less noisy. The permanent magnet rotating electric machine includes a stator with multi-phase stator windings and a rotor with a plurality of permanent magnets internally embedded in a rotor core. The core shape of the rotor is uniform in the depth (longitudinal) direction with no skewing in the arrangement of the permanent magnets. The permanent magnets are symmetrical with respect to the rotation direction, but irregular with respect to the depth direction, for each pole. A magnetic flux generated from the between-pole permanent magnets almost equals a magnetic flux generated from the pole-center permanent magnet.Type: GrantFiled: December 8, 2005Date of Patent: June 19, 2007Assignee: Hitachi, Ltd.Inventors: Yutaka Matsunobu, Fumio Tajima, Shouichi Kawamata, Takashi Yasuhara
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Patent number: 7230359Abstract: An electric motor has a rotor (36) and a stator (28) having a lamination stack formed with slots (126). The slots have a predetermined slot pitch (?s), and a multi-phase stator winding is arranged in them. The rotor (36) has salient poles having pole shoes (136) and a magnetic return path (130). Between the return path (130) and each pole shoe (136), a recess (138, 140) is formed for receiving a permanent magnet (38). On each side of such a permanent magnet (38), a region (146a, 146b) of poor magnetic conductivity is arranged, in order to make the flux distribution in the air gap more sinusoidal. Measuring in a circumferential direction, the width (?) of a pole shoe (136) decreases with increasing distance from an interface (138) between said return path and said permanent magnet (38), and, at a place of lowest width, the pole shoe has an angular extent (?c) which has, with respect to the slot pitch (?s) between said stator slots (126), the following relationship: ?c=n*?s*(1?0.02) . . . n*?s*(1?0.Type: GrantFiled: November 3, 2004Date of Patent: June 12, 2007Assignee: ebm-papst St. Georgen GmbH & Co. KGInventor: Dorin Iles-Klumpner
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Patent number: 7221071Abstract: The electric machine (M) comprises an armature (A) and an inductor (B), the inductor (B) having for each pair of poles (N, S) of the armature (A), n teeth (20) identical to one another and n slots (21) and being provided with a winding (W) housed in the said n slots. The armature (A) has its surface facing the air gap (G) divided into 2N elements or samples (1–12) with N being a whole multiple of n, having substantially the same extent in the said direction of relative displacement, and having a respective magnetic potential value. Each sample (1–12) of the armature (A) is associated with a value of total magnetic permeance (pi) at the air gap (G) in a predetermined alignment condition between the inductor (B) and the armature (A). The armature (A) comprises a plurality of magnetically distinct ferromagnetic bodies (30, 31, 32; . . . ) each of which couples at least two armature samples in such a way as to ensure a substantial magnetic equipotentiality.Type: GrantFiled: August 28, 2003Date of Patent: May 22, 2007Assignees: C.R.F. Societa Consortile per Azioni, Tree di Fratta Antonino S.A.S.Inventor: Antonino Fratta
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Patent number: 7218019Abstract: A linear reluctance motor including a stator with a set of spaced blades each extending in the direction of the actuation axis, each blade including a plurality of alternating low permeability and high permeability teeth. A shuttle also includes a set of spaced blades each extending in the direction of the actuation axis interleaved with the blades of the stator, each blade of the shuttle also including a plurality of alternating low permeability and high permeability teeth. An active component is associated with either the stator, the shuttle, or both. The active component is divided into at least N phases, each phase including a set of blades, a flux return portion, and a coil wound to produce flux through the sets of interleaved blades in a direction substantially transverse to the actuation axis.Type: GrantFiled: December 3, 2003Date of Patent: May 15, 2007Assignee: Foster-Miller, IncInventor: Steven D. Potter
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Patent number: 7196447Abstract: A rotating electric machine comprises a stator having stator salient poles, three-phases windings wound around the stator salient poles, a rotor rotatable held inside the stator, and permanent magnets inserted into the rotor and positioned opposite to the stator salient poles. Three-phase windings, which are concentratively wound around each of the stator salient poles, are wound around more than one stator salient pole. The windings of each phase have a phase difference of voltage between at least one of the windings and the other.Type: GrantFiled: September 26, 2005Date of Patent: March 27, 2007Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.Inventors: Fumio Tajima, Yutaka Matsunobe, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keijiro Oda
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Patent number: 7157827Abstract: A spoke permanent magnet rotor that includes a shaft defining a rotor axis. A first non-magnetic end portion is coupled to the shaft and a ferromagnetic pole piece defines an aperture therethrough. A second non-magnetic end portion is positioned to dispose the pole piece between the first end portion and the second end portion. A portion of one of the first end portion and the second end portion extends through the aperture and bonds with the other of the first end portion and the second end portion.Type: GrantFiled: September 21, 2004Date of Patent: January 2, 2007Assignee: A. O. Smith CorporationInventors: Robert J. Heideman, Dan M. Ionel
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Patent number: 7151335Abstract: A permanent magnet rotating electric machine comprises a stator having stator windings wound round a stator iron core and a permanent magnet rotor having a plurality of inserted permanent magnets in which the polarity is alternately arranged in the peripheral direction in the rotor iron core. The rotor iron core of the permanent magnets is composed of magnetic pole pieces, auxiliary magnetic poles, and a stator yoke, and furthermore has concavities formed on the air gap face of the magnetic pole pieces of the rotor iron core of the permanent magnets, gently tilting from the central part of the magnetic poles to the end thereof; resulting in a permanent magnet rotating electric machine effects of iron loss are reduced, and an electric car using highly efficient permanent magnet rotating electric machine are realized.Type: GrantFiled: February 9, 2005Date of Patent: December 19, 2006Assignee: Hitachi, Ltd.Inventors: Fumio Tajima, Yutaka Matsunobu, Masashi Kitamura, Noriaki Hino, Takashi Kobayashi, Shigeru Kakugawa, Takashi Yasuhara
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Patent number: 7148597Abstract: A permanent magnet rotating electric machine uses no skewing under a predetermined current and voltage condition to prevent torque from decreasing and to decrease pulsation torque to make the machine less vibrating and less noisy. The permanent magnet rotating electric machine includes a stator with multi-phase stator windings and a rotor with a plurality of permanent magnets internally embedded in a rotor core. The core shape of the rotor is uniform in the depth (longitudinal) direction with no skewing in the arrangement of the permanent magnets. The permanent magnets are symmetrical with respect to the rotation direction, but irregular with respect to the depth direction, for each pole. A magnetic flux generated from the between-pole permanent magnets almost equals a magnetic flux generated from the pole-center permanent magnet.Type: GrantFiled: November 5, 2004Date of Patent: December 12, 2006Assignee: Hitachi, Ltd.Inventors: Yutaka Matsunobu, Fumio Tajima, Shouichi Kawamata, Takashi Yasuhara
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Patent number: 7138742Abstract: In a rotating machine, a plurality of laminated electromagnetic steel sheets constitutes at least one of a stator and a rotor and a plurality of permanent joining portions to unit each of the laminated electromagnetic steel sheets to form a corresponding one of the stator and the rotor, the plurality of permanent joining portions being set to be located at positions at which an integration value of a magnetic flux density with respect to a plane enclosed with the permanent joining portions is always zeroed.Type: GrantFiled: July 21, 2004Date of Patent: November 21, 2006Assignee: Nissan Motor Co., Ltd.Inventors: Minoru Arimitsu, Kan Akatsu
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Patent number: 7129611Abstract: A radial gap brushless electric machine (30) having a stator (31) and a rotor (32) and a main air gap (34) also has at least one stationary excitation coil (35a, 36a) separated from the rotor (32) by a secondary air gap (35e, 35f, 36e, 36f) so as to induce a secondary flux in the rotor (32) which controls a resultant flux in the main air gap (34). Permanent magnetic (PM) material (38) is disposed in spaces between the rotor pole portions (39) to inhibit the second flux from leaking from the pole portions (39) prior to reaching the main air gap (34). By selecting the direction of current in the stationary excitation coil (35a, 36a) both flux enhancement and flux weakening are provided for the main air gap (34). A method of non-diffused flux enhancement and flux weakening for a radial gap machine is also disclosed.Type: GrantFiled: September 23, 2003Date of Patent: October 31, 2006Assignee: UT-Battelle LLCInventor: John S. Hsu
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Patent number: 7122930Abstract: An electric motor including a stator with a plurality of coils wound around a ring-shaped iron core, and a rotor rotatably disposed inside the stator is provided. The rotor includes a rotor shaft and a yoke. The yoke is provided near its periphery with a plurality of plate-like permanent magnets arranged at equal pitches. Heat generated from the rotor is released through a plurality of air holes formed in the yoke between the rotor shaft and the permanent magnets.Type: GrantFiled: December 3, 2004Date of Patent: October 17, 2006Assignee: Honda Motor Co., Ltd.Inventors: Yoshihiko Yamagishi, Yoshihisa Hirose
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Patent number: 7119470Abstract: A magnetic gap is provided between a permanent magnet of a rotor and an auxiliary magnet pole portion which is arranged adjacent to the permanent magnet in a peripheral direction. A gradual change in a magnetic flux density distribution of a surface of the rotor is obtained and a cogging torque and a torque pulsation are restrained. By obtaining a reluctance torque according to the auxiliary magnetic pole, a permanent magnet electric rotating machine in which the cogging torque and the torque pulsation are restrained can be obtained and further an electromotive vehicle having the permanent magnet electric rotating machine can be provided.Type: GrantFiled: March 17, 2005Date of Patent: October 10, 2006Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
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Patent number: 7112908Abstract: There are problems in a rotor having a slit that it is difficult to increase the number of rotations of the rotor, since the centrifugal force is received at both ends of the slit, and if the connection part is made thick to increase the number of rotations, the properties of the motor is deteriorated. According to the present invention, a rotor for a synchronous motor includes a slot for generating induction torque and a slit for generating reluctance torque, the slit is filled with a filler, the slit is provided with at least one of a convex and a concave, so that the convex and the concave are formed so as to receive the centrifugal force which is generated by the rotation of the rotor and acts on a part of the rotor outside the slit and the filler so as to bulge toward the outside from the center side of the rotor by mechanical bondage of the filler and the rotor core.Type: GrantFiled: October 8, 2002Date of Patent: September 26, 2006Assignee: Mitsubishi Denki Kabushiki KaishaInventors: Yoshio Takita, Hitoshi Kawaguchi, Hayato Yoshino
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Patent number: 7109624Abstract: A synchronous electric machine includes a stator and a rotor. The stator is provided with teeth, which are wound around to establish electromagnetic fields. The rotor is provided with permanent magnets to generate magnetic fields, so that the rotor can rotate by interaction of the magnetic fields of the windings and the permanent magnets of the magnets. At least one pair of the permanent magnets is dislocated by a predetermined angle from positions where the permanent magnets is arranged at even pitch, and the predetermined angle being set to reduce electromagnetic excitation force acting on said teeth.Type: GrantFiled: March 11, 2005Date of Patent: September 19, 2006Assignee: Nissan Motor Co., Ltd.Inventors: Haruki Yashiro, Hisaaki Toujima, Kazuhiro Ooki
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Patent number: 7105974Abstract: A synchronous AC motor has a stator with stator poles arranged as a plurality of circumferentially extending stator pole groups, with each stator pole group having a pair of corresponding circumferentially extending loop-configuration stator windings disposed adjacent on either side or a single such winding disposed adjacent at one side, adjacent stator pole groups being mutually circumferentially displaced by a fixed amount corresponding to a specific electrical phase angle. A rotating magnetic field is produced by applying respective polyphase AC voltages to the windings, such that currents of mutually opposite direction flow in each pair.Type: GrantFiled: November 8, 2004Date of Patent: September 12, 2006Assignee: Denso CorporationInventor: Masayuki Nashiki
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Patent number: 7042127Abstract: A permanent magnet embedded motor including a rotor which is provided with a plurality of slits and a plurality of permanent magnets embedded into the slits and a stator which is provided with an iron core having a plurality of slots to which a coil is wound and is arranged to face the rotor via a gap. The slit includes a permanent magnet embedded part into which the permanent magnet is embedded in a direction perpendicular to the radial direction of the rotor and an “L”-shaped air gap part integrally provided on both ends of the permanent magnet embedded part. An angle “?1” for one pole of the rotor and an angle “?2” of the “L”-shaped air gap part are set to be 0.1??2/?1?0.3. Further, a radius “R” of a circumscribed circle of the rotor and a radius “R1” for forming an outer peripheral face of the rotor at a portion of the “L”-shaped air gap part are preferably set to be 0.1?(R?R1)/R?0.3.Type: GrantFiled: April 1, 2004Date of Patent: May 9, 2006Assignee: NIDEC Sankyo CorporationInventors: Toshifumi Tsuruta, Hideki Kanebako, Noboru Otsuki, Dongning Zhang