Skewed Patents (Class 310/156.47)
  • Publication number: 20100277027
    Abstract: A rotor for an electric machine includes a plurality of magnet stacks having at least five permanent magnets formed into a skew pattern within each of the magnet stacks. The skew pattern has a skew angle and at least two skew steps, and is an angle of rotation about the axis between individual magnets adjacent to the skew steps. The skew pattern may be an axially-symmetric V-shape. The plurality of magnet stacks may have five, six, or eight permanent magnets therein. The number of skew steps may be equal to two or three. The skew angle may be calculated as 360 degrees, divided by the number of skew steps plus one, multiplied by the least common multiple of the number of rotor poles and the number of the plurality of stator slots.
    Type: Application
    Filed: November 30, 2009
    Publication date: November 4, 2010
    Applicant: GM GLOBAL TECHNOLOGY OPERATIONS, INC.
    Inventors: Edward L. Kaiser, Khwaja M. Rahman
  • Patent number: 7750522
    Abstract: A direct-drive generator and assembly procedure for that generator include a permanent magnet assembly that is partitioned and assembled piece-by-piece after the rotor and stator have been attached. The magnets are attached to a plate in columns, and adjacent columns have a N-S orientation. The air gap between the rotor and stator is variable, and application of an input torque produces a first cogging torque in a first direction due to the variable air gap that offsets a second cogging torque in a second opposite direction.
    Type: Grant
    Filed: July 18, 2007
    Date of Patent: July 6, 2010
    Assignee: Danotek Motion Technologies
    Inventors: Daniel Gizaw, David M. Erdman, Joseph E. Miller, Girma Desta
  • Publication number: 20100133940
    Abstract: A three-phase dynamoelectrical permanently excited synchronous machine includes a stator with teeth which point to a rotor, wherein twelve slots are formed between the teeth. The slots have coil sides of coils of a winding system in such a manner that two coil sides of different coils are situated in each slot. The rotor has a cylindrical support structure which is provided with permanent magnets defined by an inner radius which corresponds to a radius of the support structure, and by an outer radius which is smaller than their inner radius. The permanent magnets are formed with ten magnet poles when viewed in a circumferential direction.
    Type: Application
    Filed: November 30, 2009
    Publication date: June 3, 2010
    Applicant: Siemens Aktiengesellschaft
    Inventors: UDO GROSSMANN, Holger Schunk, Rolf Vollmer, Michael Zastrow
  • Patent number: 7728469
    Abstract: In a motor driving apparatus, an incline of boundary lines of magnetic poles with respect to a rotating shaft of a rotor and an incline in a movable direction of a magnetic detection unit with respect to the rotating shaft of the rotor are different.
    Type: Grant
    Filed: September 11, 2008
    Date of Patent: June 1, 2010
    Assignee: Canon Kabushiki Kaisha
    Inventor: Hiromu Yasuda
  • Publication number: 20100117476
    Abstract: An electrical machine has at least two separate groups of at least two circumferentially adjacent magnet poles. One of the circumferentially outer magnet poles in one of the groups of magnet poles is defined as being in its reference position. The reference position of each other magnet pole is defined as the position each other magnet pole would occupy if all the magnet poles were equally circumferentially spaced around the first or second body and the one circumferentially outer pole was in its reference position. At least one of the circumferentially outer magnet poles in each group is sited in its reference position. At least one magnet pole in each group is a displaced magnet pole and is sited in a position that is displaced from its reference position by an amount that is not equal to an integral multiple of the reference angular pitch of the winding slots. The displacement of the magnet poles provides a pronounced reduction in cogging.
    Type: Application
    Filed: January 14, 2010
    Publication date: May 13, 2010
    Applicant: Converteam Ltd
    Inventor: Paul Eaton CLARK
  • Publication number: 20100117475
    Abstract: An internal permanent magnet machine has multiple rotor sections, each section having multiple rotor laminations. Permanent magnets are placed asymmetrically in lamination openings to attenuate oscillations in torque caused by harmonic components of magnetic flux.
    Type: Application
    Filed: November 11, 2008
    Publication date: May 13, 2010
    Applicant: FORD GLOBAL TECHNOLOGIES, LLC
    Inventors: Franco Leonardi, Michael W. Degner, Feng Liang
  • Patent number: 7667364
    Abstract: A brushless motor includes a stator and a rotor. The stator includes an annular stator core having teeth arranged with a spacing in a circumferential direction of the annular stator core; and coils wound around the teeth respectively. The rotor includes a rotor core and magnetic poles of segment magnets arranged annularly along a circumferential direction of the rotor core. The segment magnets are stacked at a plurality of stages in an axial direction of the rotor core. A length direction of each of the segment magnets is parallel with the axial direction of the rotor core. The following expression is satisfied: (2×?/P)+?<(360/P) where P is the number of the magnetic poles of the segment magnets at each stage, ? (electrical angle) is the effective pole angular aperture on the outer peripheral surface of the rotor core, and ? is the skew angle equivalent to a phase shift angle between the corresponding magnetic poles of the segment magnets at the adjacent stages.
    Type: Grant
    Filed: July 17, 2008
    Date of Patent: February 23, 2010
    Assignee: Jtekt Corporation
    Inventors: Noboru Niguchi, Masaru Horikawa
  • Publication number: 20100019587
    Abstract: A radial anisotropic sintered magnet formed into a cylindrical shape includes a portion oriented in directions tilted at an angle of 30° or more from radial directions, the portion being contained in the magnet at a volume ratio in a range of 2% or more and 50% or less, and a portion oriented in radial directions or in directions tilted at an angle less than 30° from radial directions, the portion being the rest of the total volume of the magnet. The radial anisotropic sintered magnet has excellent magnet characteristics without occurrence of cracks in the steps of sintering and cooling for aging, even if the magnet has a shape of a small ratio between an inner diameter and an outer diameter.
    Type: Application
    Filed: October 6, 2009
    Publication date: January 28, 2010
    Applicant: Shin-Etsu Chemical Co., Ltd.
    Inventors: Koji SATO, Mitsuo Kawabata, Takehisa Minowa
  • Patent number: 7626300
    Abstract: In a radially anisotropic sintered magnet of annular shape, the remanence in a radial direction of the annulus increases and decreases at intervals of 90° in a circumferential direction of the annulus, and the remanence in a radial direction over the entire circumference of the annulus has a maximum of 0.95-1.60 T and a minimum equal to 50-95% of the maximum. In a permanent magnet motor comprising a plurality of stator teeth, the radially anisotropic annular sintered magnet is incorporated after it is magnetized in 4n poles (wherein n is an integer of 1 to 20) so that the boundary between N and S poles is located within the range that is centered at the radial direction where the remanence exhibits the minimum and extends ±10° therefrom in a circumferential direction. The radially anisotropic annular sintered magnet undergoes neither fracture nor cracking during the sintering and aging/cooling steps even when it is shaped to a low inner/outer diameter ratio and has satisfactory magnetic properties.
    Type: Grant
    Filed: June 20, 2005
    Date of Patent: December 1, 2009
    Assignee: Shin-Etsu Chemical Co., Ltd.
    Inventors: Koji Sato, Takehisa Minowa
  • Publication number: 20090243416
    Abstract: An electric motor having a stator and a mover is disclosed. The stator has excitation coils of three phases, and the mover is movable relative to the stator. The mover has an opposed surface facing the excitation coils. Field poles or protrusions are provided on the opposite surface. The field poles or the protrusions extend helically about the axis of the mover. Each excitation coil extends helically in the same direction as the field pole or the protrusion about the axis of the mover so as to face the field pole or the protrusion.
    Type: Application
    Filed: March 31, 2009
    Publication date: October 1, 2009
    Inventor: Yasuhide ITO
  • Patent number: 7569961
    Abstract: The present invention provides a rotor for motors, in which motor torque is kept high and generation of torque ripples is reduced, and what is more, detecting accuracy of a magnetic pole position is not deteriorated. The present invention provides a rotor assembly having a first divided rotor magnetic pole unit 15 and a second divided rotor magnetic pole unit 17 are disposed side by side on a surface of a rotor core 13 in an axial direction of a rotary shaft 11. The first divided rotor magnetic pole unit 15 includes P (P is a positive even number) permanent magnet magnetic pole portions 21 of a first kind and P (P is the positive even number) salient pole portions 23 made of a magnetic material, which are alternately disposed in a circumferential direction of the rotary shaft 11.
    Type: Grant
    Filed: May 30, 2007
    Date of Patent: August 4, 2009
    Assignee: Sanyo Denki Co., Ltd.
    Inventor: Toshihito Miyashita
  • Publication number: 20090160283
    Abstract: The aim of the invention is to provide a linear rotation drive wherein the oscillating torques are reduced to a minimum and whose rotation drive is devoid of axial forces. For this purpose, a magnet of the linear rotation drive is provided with sloped sections or a plurality of magnet sections is configured to give at least two sloped magnet arrangements which are symmetric to a line extending in the circumferential direction of the linear rotation drive. Oscillating torques can also be avoided by distributing the magnets across the circumference of the rotor or stator in an uneven manner. Favorable results can be obtained when the least common multiple of the number of grooves and the number of poles is as high as possible.
    Type: Application
    Filed: November 16, 2005
    Publication date: June 25, 2009
    Inventors: Erich Bott, Matthias Braun, Holger Schunk, Rolf Vollmer
  • Patent number: 7541710
    Abstract: Provided is a rotating electric machine which can restrain vibration and noise induced by a radial electromagnetic force of the rotating electric machine, and in which a rotor is divided into first to fourth four rotating pieces having axial lengths of 0.29L, 0.71L, 0.71L and 0.29L where 2L is an axial length of a rotor or stator core, and secondary conductors defining effective magnetic pole opening angles, are arranged being shifted by a value which is equal to a phase difference of electric angle between axial sections of the rotor pieces in order to define skews so that phase differences of electric angles are continuous between axial sections of the first and second rotor pieces, the skews being continuous between the third and fourth rotor pieces but being not continuous between the second and third rotor pieces arranged being shifted by a value which is equal to a phase difference of electric angle between axial sections of the rotor.
    Type: Grant
    Filed: November 30, 2005
    Date of Patent: June 2, 2009
    Assignee: Hitachi, Ltd.
    Inventors: Kanako Nemoto, Yasushi Takano, Kazuhiko Takahashi, Kazuo Shima, Kazuo Nishihama
  • Patent number: 7535149
    Abstract: To reduce the torque ripple of permanent-magnet excited synchronous motors (1) having tooth coils (6), constructive means are proposed for damping or eliminating the fifth and/or seventh harmonic wave of the rotor field which mainly cause torque ripple.
    Type: Grant
    Filed: June 2, 2004
    Date of Patent: May 19, 2009
    Assignee: Siemens Aktiengesellschaft
    Inventor: Detlef Potoradi
  • Patent number: 7518277
    Abstract: The vibration and noise excited by the electromagnetic exciting force in the radial direction of an electric motor are suppressed. In an electric motor 100, a rotor 1 is divided into four rotor pieces 3, 4, 5, and 6 for an axial length of 2L of one group of the rotor core, and for example, the four rotor pieces 3, 4, 5, and 6 are ideally 0.29L, 0.71L, 0.71L, and 0.29L in axial length in the axial direction, and permanent magnets 2 of the rotor pieces 3, 4, 5, and 6 are arranged in the circumferential direction so that the phase differences of the electrical angle are 0, ?, 0, and ?. Further, when an effect is obtained even if the ideal axial length is changed, the tolerance of the aforementioned axial length is ±0.1L.
    Type: Grant
    Filed: May 26, 2004
    Date of Patent: April 14, 2009
    Assignees: Hitachi, Ltd., Nissan Motor Co., Ltd.
    Inventors: Kanako Nemoto, Yasushi Takano, Michiyuki Takagi, Fumio Tajima, Akira Nezu, Tsukasa Yamazaki, Shunji Ooki, Masahide Kimura, Yasushi Fujita
  • Publication number: 20090046421
    Abstract: A brushless DC electric fan cools an information handling system with reduced audible noise by skewing a seam in a permanent magnet relative to a rotation axis of the fan. For instance, the permanent magnet is formed from a sheet of magnetic material having a parallelogram shape. The parallelogram is rolled into a cylindrical shape having a seam skewed relative to the axis of rotation of the cylinder. The discontinuity in the magnetic field is moderated by passing the seam through the magnetic field over several degrees of rotation, such as approximately ten degrees.
    Type: Application
    Filed: August 15, 2007
    Publication date: February 19, 2009
    Inventor: Richard Sohaney
  • Patent number: 7443061
    Abstract: A driving device which is capable of delivering higher power and can be reduced in size. A hollow-cylindrical magnet (1) is magnetized so as to have circumferentially alternately different poles. First and second coils (2 and 3) are arranged concentric with the magnet (1) on respective axially opposite sides thereof. Tooth-shaped first and second outer magnetic pole parts (8A, 8B, 8C, 8D, 9A, 9B, 9C, and 9D) are arranged in opposed relation to the magnet (1) to extend from respective opposite end faces of the magnet (1), for being magnetized by the first and second coils (2 and 3). A rotary shaft (10) fixed to an inner periphery of the magnet (1) is formed with an inner magnetic pole part (10A) disposed in opposed relation to the first and second outer magnetic pole parts (8A, 8B, 8C, 8D, 9A, 9B, 9C, and 9D), for being magnetized by the first and second coils (2 and 3). The first and second outer magnetic pole parts (8A, 8B, 8C, 8D, 9A, 9B, 9C, and 9D) are each formed into a spiral shape.
    Type: Grant
    Filed: March 28, 2006
    Date of Patent: October 28, 2008
    Assignee: Canon Kabushiki Kaisha
    Inventor: Chikara Aoshima
  • Patent number: 7397159
    Abstract: A rotary electric apparatus comprises a rotor including a first and second rotor members, a stator including a first stator and second stator members with armature coils to which armature current is supplied for synchronous rotation. The first and second rotor members are formed into a skewed type. Control means for controlling amounts ?1 and ?2 of field magnetic flux generated by the first and second rotor members, respectively, such that the amounts ?1 and ?2 differ from each other to reduce a difference between a maximum amplitude of a predetermined-order harmonic component F1 of an electromagnetic force caused by a pair of the first rotor member and the first stator member and a maximum amplitude of the predetermined-order harmonic component F2 of an electromagnetic force caused by a further pair of the second rotor member and the second stator member is reduced.
    Type: Grant
    Filed: January 24, 2005
    Date of Patent: July 8, 2008
    Assignee: Denso Corporation
    Inventor: Soichi Yoshinaga
  • Patent number: 7342338
    Abstract: A permanent magnet electric motor 10 comprises a rotor 30 provided with two stages of permanent magnets in the axial direction on an outer circumferential face of a rotor iron core, and having a shaft shifted by a stage skew angle ?r in electrical angle to decrease a first frequency component of cogging torque in the circumferential direction of the rotor iron core between two stages of the permanent magnets, a stator iron core 21 of cylindrical shape provided with the stator winding for producing a rotating magnetic field causing the rotor 30 to be rotated, and a stator 20 dividing the stator iron core 21 into plural blocks in the axial direction, and shifted by a stage skew angle ?s in electrical angle to decrease a second frequency component of the cogging torque in the circumferential direction of the stator iron core 21.
    Type: Grant
    Filed: April 11, 2003
    Date of Patent: March 11, 2008
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Takashi Miyazaki, Tomohiro Kikuchi, Haruyuki Kometani, Shinichi Yamaguchi
  • Patent number: 7332845
    Abstract: 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: Grant
    Filed: November 20, 2006
    Date of Patent: February 19, 2008
    Assignee: A. O. Smith Coporation
    Inventors: Robert J. Heideman, Dan M. Ionel
  • Publication number: 20080024028
    Abstract: An electric motor for reducing torque ripple includes a rotor, a plurality of magnets positioned about the rotor, and a stator including a plurality of stator teeth configured to form at least two slot openings each having a slot opening width wo and a slot opening height ho. One or more of the stator teeth include a dummy channel having a channel height wn and a channel width wb. At least one of the slot opening width wo, the slot opening height ho, the channel height wn, and the channel width wb, are selected so as to minimize or reduce cogging torque.
    Type: Application
    Filed: July 27, 2006
    Publication date: January 31, 2008
    Inventors: Mohammad S. Islam, Paul M. Fisher, Tomy Sebastian, Ramakrishnan Raja Venkitasubramony, Tom C. Wong
  • Patent number: 7307366
    Abstract: An electrical machine having a machine output rating. The electrical machine including a shaft rotatable about an electrical machine axis, a rotor coupled to the shaft and rotating with the shaft, and a stator including a stator core. The rotor is configurable to include a first rotor portion having a relation to a first output rating and a second rotor portion having a relation to a second output rating. The stator core is configurable to be disposed adjacent to the first rotor portion relative to the machine axis when the machine output rating corresponds to the first output rating and adjacent to the second rotor portion when the machine output rating corresponds to the second output rating.
    Type: Grant
    Filed: August 14, 2006
    Date of Patent: December 11, 2007
    Assignee: A.O. Smith Corporation
    Inventors: Dan M. Ionel, Stephen J. Dellinger
  • Publication number: 20070278885
    Abstract: The present invention provides a rotor for motors, in which motor torque is kept high and generation of torque ripples is reduced, and what is more, detecting accuracy of a magnetic pole position is not deteriorated. A first divided rotor magnetic pole unit 15 and a second divided rotor magnetic pole unit 17 are disposed side by side on a surface of a rotor core 13 in an axial direction of a rotary shaft 11. The first divided rotor magnetic pole unit 15 includes P (P is a positive even number) permanent magnet magnetic pole portions 21 of a first kind and P (P is the positive even number) salient pole portions 23 made of a magnetic material, which are alternately disposed in a circumferential direction of the rotary shaft 11. The second divided rotor magnetic pole unit 17 includes P (P is the positive even number) permanent magnet magnetic pole portions 25 of a second kind which are spaced on another part of the surface of the rotor core 13 in the circumferential direction of the rotary shaft 11.
    Type: Application
    Filed: May 30, 2007
    Publication date: December 6, 2007
    Applicant: SANYO DENKI CO., LTD.
    Inventor: Toshihito Miyashita
  • Patent number: 7247964
    Abstract: An electrical machine comprises a stator and a rotor. The rotor is adapted to magnetically interact with the stator to promote rotation of the rotor about an axis. The rotor includes a rotor core and a plurality of magnetized arcs supported by the rotor core. The plurality of magnetized arcs defines an outermost circumference. The rotor and the plurality of magnetized arcs include a first magnetized arc, a discontinuity disposed adjacent to the first magnetized arc along the outermost circumference, a second magnetized arc disposed adjacent to the discontinuity along the outermost circumference, and a magnetization pattern of alternating magnetic poles formed on the plurality of magnetized arcs. The magnetization pattern includes a first magnetic pole skewed with respect to a second magnetic pole to form an arc of magnetization skew.
    Type: Grant
    Filed: August 4, 2006
    Date of Patent: July 24, 2007
    Assignee: A.O. Smith Corporation
    Inventors: Dan M. Ionel, Stephen J. Dellinger
  • Patent number: 7245054
    Abstract: A permanent magnet electric machine includes a stator with salient stator poles. A rotor includes two or more axial rotor sections that are rotationally offset by an offset angle equal to the cogging angle divided by the number of axial rotor sections. The axial rotor sections include rotor poles with permanent magnets. In one embodiment, the permanent magnet electric machine has a 12/10 slot/pole combination. The permanent magnets have a magnet dimension angle between 31 and 35 degrees. An air gap ratio of the electric machine is between 1.35 and 2.5. A slot opening ratio of the electric machine is less than or equal to one. In another embodiment, the permanent magnet electric machine has an 18/12 slot/pole combination. The permanent magnets have a magnet dimension angle that is between 25 and 28 degrees. An air gap ratio of the electric machine is between 1.35 and 2.5. A slot opening ratio of the electric machine is less than or equal to one.
    Type: Grant
    Filed: November 1, 2000
    Date of Patent: July 17, 2007
    Assignee: Emerson Electric Co.
    Inventors: Todd A. Walls, Alan D. Crapo
  • Patent number: 7196445
    Abstract: A permanent-magnet rotating machine includes a rotor having a rotor core carrying on a curved outer surface multiple permanent magnets arranged in two rows along an axial direction. The permanent magnets in one row are skewed from those in the other row in a circumferential direction by a row-to-row skew angle (electrical angle) ?e. A stator having a tubular stator core in which the rotor disposed, includes stator coils for producing a rotating magnetic field for rotating the rotor. A lower limit of the row-to-row skew angle ?e larger than 30 degrees (electrical angle). A ratio, of cogging torque occurring in the absence of skew to cogging torque occurring when the permanent magnets are skewed, at a row-to-row skew angle of 30 degrees is calculated based on the cogging torque ratio, the row-to-row skew angle ?e, and B-H curve properties of the stator core.
    Type: Grant
    Filed: May 2, 2006
    Date of Patent: March 27, 2007
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shinichi Yamaguchi, Haruyuki Kometani, Tomohiro Kikuchi, Takashi Miyazaki
  • Patent number: 7183687
    Abstract: An electrical machine including a rotor rotatable about an axis and a stator adapted to magnetically interact with the rotor. The stator including (t) teeth and one or more windings with compact coils disposed around the teeth. The one or more windings having (m) phases and (p) poles, where (t) is an integer and is greater than or equal to two, where (m) is an integer and is greater than or equal to two, where (p) is an integer, is greater than or equal to two, and is an even number, and where (t/p=m/2) or (t/p=m/4).
    Type: Grant
    Filed: June 27, 2006
    Date of Patent: February 27, 2007
    Assignee: A. O. Smith Corporation
    Inventors: Dan M. Ionel, Stephen J. Dellinger
  • Patent number: 7170209
    Abstract: A rotor for a reluctance type rotating machine includes a rotor core formed by stacking a number of annular core materials each of which includes magnetic concave and convex portions. The rotor core has two keys which are formed at two positions on an inner circumference of the rotor core. The positions are spaced 180 degrees apart from each other with respect to the rotor core. The rotor core is divided into a plurality of blocks and the core materials constituting at least one block have the magnetic concave and convex portions shifted by a predetermined angle relative to the core materials constituting the other or another block on the basis of a center line passing through the keys. A whole or part of the core materials of at least one block are located circumferentially 180 degrees apart form the core materials constituting the other or another block.
    Type: Grant
    Filed: April 28, 2004
    Date of Patent: January 30, 2007
    Assignees: Kabushiki Kaisha Toshiba, Toshiba Industrial Products Manufacturing Corporation
    Inventors: Takashi Araki, Masakatsu Matsubara, Motoyasu Mochizuki, Yukihiko Kazao, Masanori Arata, Yasuo Hirano, Nobutake Aikura, Akito Kondou, Masahiko Yamashiki, Masanori Ohashi, Takashi Hanai
  • Patent number: 7157827
    Abstract: 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: Grant
    Filed: September 21, 2004
    Date of Patent: January 2, 2007
    Assignee: A. O. Smith Corporation
    Inventors: Robert J. Heideman, Dan M. Ionel
  • Patent number: 7143503
    Abstract: An electrical machine having a machine output rating. The electrical machine including a shaft rotatable about an electrical machine axis, a rotor coupled to the shaft and rotating with the shaft, and a stator including a stator core. The rotor is configurable to include a first rotor portion having a relation to a first output rating and a second rotor portion having a relation to a second output rating. The stator core is configurable to be disposed adjacent to the first rotor portion relative to the machine axis when the machine output rating corresponds to the first output rating and adjacent to the second rotor portion when the machine output rating corresponds to the second output rating.
    Type: Grant
    Filed: March 4, 2005
    Date of Patent: December 5, 2006
    Assignee: A. O. Smith Corporation
    Inventors: Dan M. Ionel, Stephen J. Dellinger
  • Patent number: 7084540
    Abstract: A magnet motor with rotor assembly is provided that has a plurality of magnet members that circumscribe a wall of the rotor core or stator in an orientation that minimizes or eliminates gaps therebetween. The magnet members can have non-parallel opposing sides to allow for elimination of the gaps. The magnet members may have trapezoidal-like shapes.
    Type: Grant
    Filed: June 20, 2003
    Date of Patent: August 1, 2006
    Assignee: General Electric Company
    Inventors: Subhash M Brahmavar, Peter B. Lytle, Kamron M. Wright
  • Patent number: 7081696
    Abstract: A polyphasie multi-coil generator includes a drive shaft, at least first and second rotors rigidly mounted on the drive shaft so as to simultaneously synchronously rotate with rotation of the drive shaft, and at least one stator sandwiched between the first and second rotors. A stator array on the stator has an array of coils mounted to the stator in a first angular orientation about the drive shaft. The rotors each have an array of magnets which are equally circumferentially spaced around the rotor and located at the same radial spacing with respect to the center of the rotor and the drive shaft. The arrays of magnets on adjacent rotors are off-set by an angular off-set relative to one another.
    Type: Grant
    Filed: January 18, 2005
    Date of Patent: July 25, 2006
    Assignee: Exro Technologies Inc.
    Inventor: Jonathan Gale Ritchey
  • Patent number: 7071592
    Abstract: A rotor for motor is disclosed to have a plurality of protruding portions arranged in two rows around the periphery of the body thereof and spaced by magnetic gaps, and a plurality of magnets of semicircular cross section respectively covered on the protruding portions and respectively abutted with one end of each of the magnets at one row against two adjacent magnets at the other row.
    Type: Grant
    Filed: June 21, 2005
    Date of Patent: July 4, 2006
    Inventor: Yi-Tang Lu
  • Patent number: 7067948
    Abstract: A permanent-magnet rotating machine includes a rotor having a rotor core carrying on a curved outer surface multiple permanent magnets arranged in two rows along an axial direction. The permanent magnets in one row are skewed from those in the other row in a circumferential direction by a row-to-row skew angle (electrical angle) ?e. A stator having a tubular stator core in which the rotor disposed includes stator coils for producing a rotating magnetic field for rotating the rotor. A lower limit of the row-to-row skew angle ?e larger than 30 degrees (electrical angle). A ratio of cogging torque occurring in the absence of skew to cogging torque occurring when the permanent magnets are skewed, at a row-to-row skew angle of 30 degrees is calculated based on the cogging torque ratio, the row-to-row skew angle ?e, and B-H curve properties of the stator core.
    Type: Grant
    Filed: October 9, 2003
    Date of Patent: June 27, 2006
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shinichi Yamaguchi, Haruyuki Kometani, Tomohiro Kikuchi, Takashi Miyazaki
  • Patent number: 7049723
    Abstract: The disclosure describes a DC motor including a rotor unit arranged within the motor body and has a cylindrical field magnet fixed to an outer surface of a holder. The holder has a rotating shaft press-fitted through the center, and the cylindrical field magnet has the S and the N poles alternately around a circumference. There is a stator unit which is circumferentially arranged around the rotor unit, that is made of a plurality of stator yokes that are arranged so that they oppose the field magnet through a small gap. Each of the stator yokes is formed by circumferentially stacking a large number of thin plates, each consisting of a salient pole, and a number of coil units, each formed by winding a magnet wire on a bobbin, and mounting the bobbins on the stator yokes. In the described arrangement, each of the S and N poles has a plurality of stages formed in an axial direction and shifted from each other in the circumferential direction by a predetermined shift amount with respect to the field magnet.
    Type: Grant
    Filed: January 14, 2002
    Date of Patent: May 23, 2006
    Assignee: Minebea Co., Ltd.
    Inventors: Yuzuru Suzuki, Sakae Fujitani, Seiichi Matsuura
  • Patent number: 7034424
    Abstract: A permanent magnet rotating machine includes a rotor with a permanent magnet having circumferential magnetic poles with a skew at boundaries between magnetic poles of the permanent magnet, and a stator having a stator iron core in an almost cylindrical shape and convex poles protruding inwardly, the rotor being disposed within the stator. A skew angle of the skew is smaller than a theoretical angle ?s (electrical angle) and larger than one-half the theoretical angle ?s, wherein the theoretical angle ?s is defined as, ?s=180×(number of magnetic poles in the rotor)/smallest integer of which both the number of magnetic poles in the rotor and the number of magnetic poles in the stator are factors) [deg.].
    Type: Grant
    Filed: June 25, 2004
    Date of Patent: April 25, 2006
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Haruyuki Kometani, Shinichi Yamaguchi, Tomohiro Kikuchi, Takashi Tamura
  • Patent number: 7002275
    Abstract: An electric motor, particularly an electronically commutated direct current motor, has a stator and a rotor. The stator and the rotor are arranged coaxially to a longitudinal axis of the electric motor. The stator features a plurality of electrical stator poles and a plurality of phase windings. The rotor features a permanent magnet with a least one magnetic pole pair which is dedicated to the phase windings. The phase windings and/or the permanent magnet are divided into several axial sections in the direction of the longitudinal axis of the electric motor and these sections are staggered around the longitudinal axis of the electric motor with respect to each other. Angular positions of the individual phases are offset with respect to each other is in such a way that torque ripple can be reduced and torque gaps can be prevented.
    Type: Grant
    Filed: February 3, 2004
    Date of Patent: February 21, 2006
    Assignee: Minebea Co., Ltd.
    Inventor: Helmut Hans
  • Patent number: 6956311
    Abstract: A magnetic motor includes rotors having permanent magnets and rotatably disposed around a rotating axis, a magnetic sensor disposed at a periphery of the rotors and a plurality of electro-magnetic coils, and control means which controls electric current to the coils based on detection of magnetism from the magnets by means of the sensor. The rotor is equidistantly divided in a circumferential direction into the same number of regions as that of the coils. Each region includes a portion wherein a plurality of magnets are disposed in a circumferential direction and a portion wherein no magnets are disposed. Each magnet is disposed inclined against a radial line extending outwardly from the rotating axis. The control means switches the direction of electric current to the coils based on the signal from the sensor and supplies current after a lapse of predetermined time from the detection of magnetism by the sensor.
    Type: Grant
    Filed: February 27, 2002
    Date of Patent: October 18, 2005
    Inventor: Akira Hosaka
  • Patent number: 6943476
    Abstract: A magneto generator for self-powered apparatuses; the magneto generator comprises a stator provided with an electric winding, and a permanent magnet rotor coaxially arranged to the stator. The stator and the rotor have a first, and respectively a second pole system which together with the electric winding define a multiphase electromagnetic system connected to a bridge rectifier, secured to the stator. The poles of the stator and the poles of the rotor have opposite polar surfaces in which the axis of each polar surface of the rotor, is slanted with respect to a reference line parallel to the longitudinal axes of the polar surfaces of the stator.
    Type: Grant
    Filed: June 14, 2004
    Date of Patent: September 13, 2005
    Assignee: Ducati Energia S.p.A.
    Inventors: Gianni Regazzi, Manuel Cocchi
  • Patent number: 6940198
    Abstract: An electrical machine comprises a stator and a rotor. The rotor includes a plurality of stator teeth and a winding with compact coils disposed on the teeth. The winding has (m) phases and (p) poles; where (m) is an integer and is greater than or equal to two; where (p) is an integer, is greater than or equal to two, and is an even number. The rotor has a magnetization pattern including a magnetization skew. In some constructions, each stator includes one or more channels along a surface adjacent to the rotor. The channels can be of various shapes including a trapezoidal shape or a curvilinear shape.
    Type: Grant
    Filed: July 24, 2003
    Date of Patent: September 6, 2005
    Assignee: A. O. Smith Corporation
    Inventors: Dan M. Ionel, Stephen J. Dellinger
  • Patent number: 6927519
    Abstract: Rotor assembly for an electrical machine, wherein a body of generally cylindrical shape having an inner opening for coaxially mounting the body on a shaft, permanent magnets embedded in said body, wherein at least one of the permanent magnets is split in at least two magnet sections which extend from about the inner opening towards the outer periphery of the body and are inclined towards a plane, which extends in a radial direction of the body.
    Type: Grant
    Filed: August 6, 2003
    Date of Patent: August 9, 2005
    Assignee: Minebea Co., Ltd.
    Inventor: Vladimir Vladimirovich Popov
  • Patent number: 6906443
    Abstract: A brushless DC permanent magnet motor having a step skewed rotor including a rotor shaft having a portion having a substantially uniform cross sectional configuration defined by N planar sides of substantially equal length and width wherein N is equal to the number of poles of the motor, first and second annular sets of N number of substantially identically shaped bread loaf magnets one of which is attached to each of the N planar sides of the rotor shaft wherein the magnets of the first set have their orientation reversed with respect to the magnets of the second set and the magnets of the first set are offset or skewed by a predetermined skew angle from the magnets of the second set of magnets to form a stepped skewed rotor.
    Type: Grant
    Filed: April 21, 2003
    Date of Patent: June 14, 2005
    Assignee: Eaton Corporation
    Inventors: Jian Luo, Maria Hernandez, John Laskowsky, Jose Antonio Hernandez
  • Patent number: 6876116
    Abstract: A permanent magnet motor having a rotor with permanent magnets disposed on the outer circumferential face at a predetermined interval in a peripheral direction, and a stator with magnetic pole pieces arranged at a predetermined spacing in the peripheral direction, the magnetic pole pieces being opposed to the permanent magnets, the stator surrounding the rotor, wherein auxiliary grooves are provided on a face of each magnetic pole piece of the stator opposed to the permanent magnets of the rotor, and a skew having an electric angle in a range of 61° to 84° is provided relatively between the rotor and the stator.
    Type: Grant
    Filed: August 24, 2004
    Date of Patent: April 5, 2005
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Masatsugu Nakano, Tsutomu Tominaga, Hideki Megata, Masafumi Okazaki
  • Patent number: 6876115
    Abstract: Several embodiments of rotating electrical machines where cogging torque is reduced as well as the distortion of the back emf and improve torque characteristic with reduced torque ripples by dividing either the permanent magnets and/or the poles of the coil windings in axially separated portions that are circumferentially shifted relative to each other.
    Type: Grant
    Filed: February 9, 2004
    Date of Patent: April 5, 2005
    Assignee: Kabushiki Kaisha Moric
    Inventors: Hideaki Takahashi, Koichi Sano
  • Patent number: 6870293
    Abstract: To provide a motor which can suppress vibration and noise during an operation of a concentrated winding motor and can achieve low vibration and low noise with high efficiency. Skew is formed on at least one of a stator (10) provided with concentrated windings and a rotor (20), and the windings (13—13) of different phases in a groove (19) for windings are brought into contact with each other directly or via an insulating material.
    Type: Grant
    Filed: July 11, 2002
    Date of Patent: March 22, 2005
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hisakazu Kataoka, Hiroshi Murakami, Hideharu Hiwaki, Sunao Hashimoto, Yasuharu Odachi, Hirohito Hayashi
  • Patent number: 6867525
    Abstract: An electrical machine having a machine output rating. The electrical machine including a shaft rotatable about an electrical machine axis, a rotor coupled to the shaft and rotating with the shaft, and a stator including a stator core. The rotor is configurable to include a first rotor portion having a relation to a first output rating and a second rotor portion having a relation to a second output rating. The stator core is configurable to be disposed adjacent to the first rotor portion relative to the machine axis when the machine output rating corresponds to the first output rating and adjacent to the second rotor portion when the machine output rating corresponds to the second output rating.
    Type: Grant
    Filed: July 24, 2003
    Date of Patent: March 15, 2005
    Assignee: A.O. Smith Corporation
    Inventors: Dan M. Ionel, Stephen J. Dellinger
  • Patent number: 6867514
    Abstract: A motor providing unidirectional rotational motive power is provided. The motor has a generally circular stator with a stator axis, an outer surface, and a circumferential line of demarcation at about a midpoint of the outer surface. The motor also includes one or more stator magnets attached to the outer surface of the stator. The stator magnets are arranged in a generally circular arrangement about the stator axis and generate a first magnetic field. An armature is attached to the stator for rotation therewith, the armature having an axis parallel to the stator axis. One or more rotors, are spaced from the armature and coupled thereto by an axle for rotation about an axis of each rotor, each rotor rotating in a plane generally aligned with the armature axis. Each rotor includes one or more rotor magnets, with each rotor magnet generating a second magnetic field.
    Type: Grant
    Filed: September 7, 2004
    Date of Patent: March 15, 2005
    Inventor: Frank J. Fecera
  • Patent number: 6867524
    Abstract: A permanent magnet motor to reduce torque ripple includes a rotor having at least three segments. Each of the three segments is formed sequentially adjacent and aligned along an axis of the rotor. Each segment has at least one pair of permanent magnets disposed at a substantially equal interval in a peripheral direction of the rotor. First and second segments are skewed relative to each other by a first angular displacement, and the first and third segments are skewed relative to each other by a second angular displacement. The first and second angular displacements are selected to cause a net sum of torque ripple produced by each of the segments to be substantially equal to zero during an operation of the motor.
    Type: Grant
    Filed: June 4, 2003
    Date of Patent: March 15, 2005
    Assignee: Ford Global Technologies, LLC
    Inventor: Feng Liang
  • Patent number: 6858960
    Abstract: The present invention minimizes variations in torque due to cogging in a permanent magnet brushless electric motor and, among other things, specifies a topology of a rotor and a stator in relation to one another. According to one embodiment, a permanent magnetic motor includes a housing surrounding a stator that in turn surrounds a rotor rotatably mounted to the housing. The stator has a stator cross section including a plurality of uniformly distributed and spaced apart stator poles separated by slots. The stator poles extend radially inward from the inner surface and terminate at an end defined by an inner pole face. Each end is separated from an adjacent end by a distance defined as a stator slot width W. The rotor cross section includes a plurality of spaced apart permanent magnets carried by the shaft and angularly and uniformly distributed about the shaft.
    Type: Grant
    Filed: September 17, 2002
    Date of Patent: February 22, 2005
    Assignee: Dana Corporation
    Inventor: Jerzy Muszynski
  • Patent number: 6853105
    Abstract: A permanent magnet motor having a rotor with permanent magnets disposed on the outer circumferential face at a predetermined interval in a peripheral direction, and a stator with magnetic pole pieces arranged at a predetermined spacing in the peripheral direction, the magnetic pole pieces being opposed to the permanent magnets, the stator surrounding the rotor, wherein the auxiliary grooves are provided on a face of each magnetic pole piece of the stator opposed to the permanent magnets of the rotor, and a skew having an electric angle of 72° is provided relatively between the rotor and the stator.
    Type: Grant
    Filed: September 3, 2002
    Date of Patent: February 8, 2005
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Masatsugu Nakano, Tsutomu Tominaga, Hideki Megata, Masafumi Okazaki