With Slots Or Holes To Guide Flux Patents (Class 310/156.57)
  • Publication number: 20090152972
    Abstract: 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: Application
    Filed: February 1, 2006
    Publication date: June 18, 2009
    Applicant: Daikin Industries, Ltd.
    Inventor: Kiyotaka Nishijima
  • Patent number: 7545068
    Abstract: A rotor for use in an induction motor includes a main body installed to be rotatable by having a gap inside a stator, providing a flow path of magnetic fluxes produced from the coil, and including a plurality of conductors formed on an edge region of the main body; a pair of barriers formed to pass through the main body in a manner to have a semi-spherical shape from a sectional view, base lines of the semi-spherical shape being disposed to face each other; and a plurality of permanent magnets disposed inside the individual barriers. Therefore, the permanent magnets can be easily affixed to the inner side of the individual barriers, and the loss of the magnetic fluxes is minimized, thereby improving the efficiency of the rotor.
    Type: Grant
    Filed: November 22, 2006
    Date of Patent: June 9, 2009
    Assignee: Daewoo Electronics Corporation
    Inventor: Man Seung Han
  • Patent number: 7521832
    Abstract: 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: Grant
    Filed: December 15, 2006
    Date of Patent: April 21, 2009
    Assignee: Hitachi, Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobu, Masashi Kitamura, Noriaki Hino, Takashi Kobayashi, Shigeru Kakugawa, Takashi Yasuhara
  • Patent number: 7479723
    Abstract: A rotor for an interior permanent magnet machine has a rotor body having an output shaft and a first cavity filled with magnetic material. Second cavities are disposed inboard of the first cavities and are not filled with magnetic material. Non-magnetic rods extend through the second cavities and protrude beyond end faces of the rotor body. The rods are press-fit in blind bores formed in non-magnetic end plates disposed adjacent the end faces of the rotor body. Shrink disks are shrunk around projecting ends of the output shaft in abutting relation with the end plates. In order to prevent induced voltage from generating current in the cage formed by the rods and end plates, an oxide layer is disposed between the rods and blind bores in the end plates.
    Type: Grant
    Filed: January 30, 2007
    Date of Patent: January 20, 2009
    Assignee: GM Global Technology Operations, Inc.
    Inventors: Robert T Dawsey, Constantin C. Stancu, Eric R. Ostrom, Young Doo
  • Patent number: 7474029
    Abstract: 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: Grant
    Filed: June 14, 2004
    Date of Patent: January 6, 2009
    Assignee: General Motors Corporation
    Inventors: Khwaja M. Rahman, James M. Nagashima
  • Patent number: 7459821
    Abstract: 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: Grant
    Filed: January 4, 2005
    Date of Patent: December 2, 2008
    Assignee: LG Electronics Inc.
    Inventors: Dal Ho Cheong, Kyung Hoon Lee, Hyun Hun Shin, June Hee Won, Jae Yoon Oh, Gil Su Lee
  • Patent number: 7446448
    Abstract: 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: Grant
    Filed: August 25, 2006
    Date of Patent: November 4, 2008
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Patent number: 7432624
    Abstract: 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: Grant
    Filed: August 26, 2003
    Date of Patent: October 7, 2008
    Assignee: ABB OY
    Inventors: Jere Kolehmainen, Jari Pekola, Jouni Ikaheimo
  • Publication number: 20080224558
    Abstract: An electric machine includes a stator, and a rotor positioned adjacent the stator and configured to rotate with respect to the stator. The rotor includes a plurality of laminations having an outside diameter and stacked in a stackwise direction. Each lamination includes a plurality of non-linear slots positioned inward of the outside diameter. Each non-linear slot includes an inner portion spaced a first distance from the outside diameter and two end portions disposed a second distance from the outside diameter. The second distance is smaller than the first distance. The rotor also includes a plurality of permanent magnets. Each magnet is disposed in one of the non-linear slots.
    Type: Application
    Filed: March 17, 2008
    Publication date: September 18, 2008
    Applicant: A. O. SMITH CORPORATION
    Inventor: Dan M. Ionel
  • Patent number: 7425786
    Abstract: 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: Grant
    Filed: November 30, 2005
    Date of Patent: September 16, 2008
    Assignee: Hitachi, Ltd.
    Inventors: Noriaki Hino, Yutaka Matsunobu, Fumio Tajima, Takashi Yasuhara
  • Patent number: 7420306
    Abstract: A brushless DC motor prevents disconnection of a magnetic flux and to minimize leakage of the magnetic flux, thereby reducing torque ripple. A plurality of magnetic flux-disconnection preventing holes are arranged in an outer periphery of a rotor core between installing holes into which magnets are fitted. The plurality of magnetic flux-disconnection preventing holes are symmetrical at both sides about a first line connecting a center of the rotor core to a center between the adjacent installing holes, and an angle between the first line and a second line connecting the center of the rotor core to an outermost end of the plurality of magnetic flux-disconnection preventing holes is about 15˜20°. A length between an outer periphery of the rotor core and an outer periphery of the plurality of magnetic flux-disconnection preventing holes is smaller than a gap between the rotor core and the stator.
    Type: Grant
    Filed: September 20, 2005
    Date of Patent: September 2, 2008
    Assignee: Samsung Electronics Co., Ltd.
    Inventors: Sang Hoon Park, Hyung Chul Lee, Sang Yong An, Chun Mo Sung, Yun Seok Kim, Bum Young Byun
  • Patent number: 7405504
    Abstract: 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: Grant
    Filed: September 13, 2005
    Date of Patent: July 29, 2008
    Assignees: Nissan Motor Co., Ltd., National University Corporation Tokyo University of Agriculture and Technology
    Inventors: Minoru Arimitsu, Kan Akatsu
  • Patent number: 7378773
    Abstract: 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: Grant
    Filed: August 25, 2006
    Date of Patent: May 27, 2008
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Patent number: 7362025
    Abstract: At each permanent magnet in a rotor of an IPM rotary electric machine, each of a pair of flux barriers respectively disposed adjoining circumferentially opposed side faces of the magnet is formed with a trench portion that extends farther from a circumferential face of the rotor than a position on a corresponding side face that is located farthest, on that side face, from the rotor circumferential face. This prevents part of a flow of magnetic flux, from the stator through the rotor, from being diverted to flow into the magnet. Increased torque or output power is thereby achieved.
    Type: Grant
    Filed: May 24, 2005
    Date of Patent: April 22, 2008
    Assignee: Denso Corporation
    Inventor: Ryosuke Utaka
  • Patent number: 7358638
    Abstract: An interior permanent magnet rotary motor of the present invention has N slots and P permanent magnet magnetic pole sections, (?<=P/N<= 43/45). Po is an irreducible fraction Po/No of the P/N is an odd number, and a pole arc ratio ?p equals ?pp/?p. ?pp is an angle between two line segments assumed for a pair of flux barriers, each of which connects the center of a rotor core and one of corners of the section of each flux barrier that is closest to the surface of the rotor core. ?p is an angle obtained by dividing 360° by the number of the permanent magnet pole sections. The pole arc ratio indicated by ?p (0<4n<1) is determined by the expression of ?p=2mP/N+P/4LCM (P, N)?2n, where LCM (P, N) is the least common multiple between P and N, m and n are arbitrary natural numbers.
    Type: Grant
    Filed: February 4, 2005
    Date of Patent: April 15, 2008
    Assignee: Sanyo Denki Co., Ltd.
    Inventors: Toshihito Miyashita, Satoru Onodera
  • Patent number: 7327062
    Abstract: A rotor (10) for a rotary electric machine (1) comprises a rotation shaft (11), and a plurality of rotor cores (120-129) fixed to the rotation shaft (11) and axially split. The rotor cores (120-129) have outer peripheral surfaces (120A-129A) with a circular cross section. Permanent magnets (13) extending through the rotor cores (120-129) are arranged at equal circumferential intervals. Voids (120B-129B) extending axially through the rotor cores (120-129) are formed between the outer peripheral surfaces (120A-129A) and the permanent magnets (13). The voids (120B-129B) of two adjacent rotor cores (120-129) are formed at circumferentially different positions, thereby being capable of suppressing the cogging torque without introducing a reduction in output torque.
    Type: Grant
    Filed: December 2, 2004
    Date of Patent: February 5, 2008
    Assignee: Nissan Motor Co., Ltd.
    Inventor: Yutaro Kaneko
  • Patent number: 7282827
    Abstract: 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: Grant
    Filed: July 28, 2004
    Date of Patent: October 16, 2007
    Assignee: Kabushiki Kaisha Toshiba
    Inventor: Toshihiko Futami
  • Patent number: 7233090
    Abstract: An electrical machine, in particular a brushless synchronous motor has a stator (14) and a rotor (12) with salient poles (18) disposed distributed over its circumference, each of which poles has an enclosed permanent magnet (11) and a pole shoe (19) that extends radially outward from the permanent magnet and defines an air gap (13) between the stator (14) and rotor (12). In order to achieve a low cogging torque and a low torque undulation, the pole shoes (19) are embodied as magnetically anisotropic, with a preferred direction of the greater magnetic conductivity extending parallel to the radial salient pole axis.
    Type: Grant
    Filed: May 26, 2003
    Date of Patent: June 19, 2007
    Assignee: Robert Bosch GmbH
    Inventors: Steven-Andrew Evans, Susanne Evans
  • Patent number: 7176598
    Abstract: A bridge (8) in conformity with a tooth opening angle of the stator (1) is provided between a permanent magnet (5) and a permanent magnet (5) in a rotor (4), so that a magnetic flux for a reluctance torque is made to pass an inner side of the permanent magnet (5). An opening angle of each of ribs (7) on both sides of the permanent magnet (5) is set to be equal to or smaller than the teeth interval opening angle and equal to or larger than a half thereof. Thereby, reluctance of the rib (7) against a magnetic flux in a circumferential direction is increased and leakage of the magnetic flux of the permanent magnet (5) is prevented.
    Type: Grant
    Filed: February 11, 2005
    Date of Patent: February 13, 2007
    Assignee: Koyo Seiko Co., Ltd.
    Inventors: Sadaaki Mori, Hirohide Inayama, Atsushi Ishihara, Tomofumi Takahashi, Minoru Kitabayashi, Tetsuo Horie
  • Patent number: 7122930
    Abstract: 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: Grant
    Filed: December 3, 2004
    Date of Patent: October 17, 2006
    Assignee: Honda Motor Co., Ltd.
    Inventors: Yoshihiko Yamagishi, Yoshihisa Hirose
  • Patent number: 7119470
    Abstract: 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: Grant
    Filed: March 17, 2005
    Date of Patent: October 10, 2006
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Patent number: 7102264
    Abstract: A synchronous induction motor features improved assemblability of a rotor, significantly reduced production cost, and improved operation performance of the motor. A plurality of die-cast secondary conductors is provided around a rotor yoke constituting the rotor of the synchronous induction motor. End rings are die-cast integrally with the secondary conductors on the peripheral portions of both end surfaces of the rotor yoke. Permanent magnets are inserted into slots formed such that they penetrate the rotor yoke. The openings of both ends of the slots are closed by a pair of end surface members formed of a non-magnetic constituent. One of the end surface members is secured to the rotor yoke by one of the end rings when the secondary conductors and the end rings are formed. The other end surface member is secured to the rotor yoke by a fixture.
    Type: Grant
    Filed: July 29, 2004
    Date of Patent: September 5, 2006
    Assignee: Sanyo Electric Co., Ltd.
    Inventors: Toshihito Yanashima, Keijiro Igarashi, Masaaki Takezawa, Kazuhiko Arai, Eiichi Murata, Noboru Onodera, Shigemi Koiso, Kazuhiro Enomoto, Yoshitomo Nakayama
  • Patent number: 7053513
    Abstract: A rotary electric machine includes inner and outer rotors each including permanent magnets, and a stator including stator coils, disposed between the inner and outer rotors. The inner rotor further includes outer surface portions serving as a yoke portion of an outer magnetic circuit for magnetic flux synchronous with the outer rotor, and the outer rotor further includes outer portions each located on an outer side of one of the outer permanent magnet, and arranged to serve as a yoke portion of an inner magnetic circuit for magnetic flux synchronous with the inner rotor.
    Type: Grant
    Filed: October 7, 2004
    Date of Patent: May 30, 2006
    Assignee: Nissan Motor Co., Ltd.
    Inventors: Hisaaki Toujima, Minoru Arimitsu
  • Patent number: 7038345
    Abstract: An electric machine (M) comprises a field (A) and an armature (B) between which is defined an air gap (G). The field (A) has at least one pair of poles (N, S) and the armature (B) has n teeth (20) and n slots (21) per pair of poles (N, S) of the field (A). The surface of the field (A) facing the air gap (G) is divided into 2n elements or samples (1–12) having the same extent along the direction of relative displacement between armature and field, and having a respective magnetic potential value (?i). Each sample (1–12) of the field (A) has a respective total permeance value (pi) at the air gap (G) in a predetermined relative position between armature (B) and field (A). The field (A) comprises a plurality of magnetically distinct ferromagnetic bodies (30, 31, 32, . . . ) each of which couples at least two samples of the field in such a way as to ensure a substantial magnetic equipotentiality.
    Type: Grant
    Filed: February 28, 2002
    Date of Patent: May 2, 2006
    Assignees: C.R.F. Societa' Consortile per Azioni, Tree di Fratta Antonino S.a.s.
    Inventor: Antonino Fratta
  • Patent number: 7019426
    Abstract: A bridge (8) in conformity with a tooth opening angle of the stator (1) is provided between a permanent magnet (5) and a permanent magnet (5) in a rotor (4), so that a magnetic flux for a reluctance torque is made to pass an inner side of the permanent magnet (5). An opening angle of each of ribs (7) on both sides of the permanent magnet (5) is set to be equal to or smaller than the teeth interval opening angle and equal to or larger than a half thereof. Thereby, reluctance of the rib (7) against a magnetic flux in a circumferential direction is increased and leakage of the magnetic flux of the permanent magnet (5) is prevented.
    Type: Grant
    Filed: February 11, 2005
    Date of Patent: March 28, 2006
    Assignee: Koyo Seiko Co., Ltd.
    Inventors: Sadaaki Mori, Hirohide Inayama, Atsushi Ishihara, Tomofumi Takahashi, Minoru Kitabayashi, Tetsuo Horie
  • Patent number: 6987343
    Abstract: A motor includes a rotor including a permanent magnet type rotor unit having a plurality of permanent magnets and a reluctance type rotor unit having a plurality of salient pole portions, the rotor units being coupled to each other in an axial direction. A stator generates a field for driving the rotor. The permanent magnet type rotor unit and the reluctance type rotor unit have an angular deviation therebetween in the direction of rotation to obtain desired torque characteristics. The reluctance type rotor unit has slits for preventing flux leakage from the permanent magnets. The slits are formed with the angular deviation in the direction of rotation from respective positions symmetric about a center of the salient pole portions. Flux leakage is thus prevented to avoid deterioration in characteristics.
    Type: Grant
    Filed: December 9, 2004
    Date of Patent: January 17, 2006
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masaki Tagome, Yasuhiro Kondo, Naoyuki Kadoya
  • Patent number: 6967424
    Abstract: The present invention relates to a rotor assembly for an electrical machine, comprising: a rotor body of generally cylindrical shape having a substantially cylindrical surface configured for facing an air-gap between the rotor assembly and a stator of the electrical machine, and permanent magnets embedded in said rotor body, wherein grooves are formed in said air-gap facing surface for manipulating the distribution of magnetic flux created by said permanent magnets.
    Type: Grant
    Filed: January 16, 2004
    Date of Patent: November 22, 2005
    Assignee: Minebea Co., Ltd.
    Inventor: Vladimir Vladimirovich Popov
  • Patent number: 6919662
    Abstract: A motor including: a rotor including a permanent magnet type rotor unit having a plurality of permanent magnets and a reluctance type rotor unit having a plurality of salient pole portions, the rotor units being coupled to each other in an axial direction; and a stator for generating a field for driving the rotor. The permanent magnet type rotor unit and the reluctance type rotor unit are given an angle deviation therebetween in the direction of rotation to obtain desired torque characteristics. The reluctance type rotor unit has slits for preventing flux leakage from the permanent magnets. The slits are formed with the angle deviation in the direction of rotation from respective positions symmetric about a center of the salient pole portions. Flux leakage is thus prevented to avoid deterioration in characteristics.
    Type: Grant
    Filed: April 25, 2002
    Date of Patent: July 19, 2005
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Masaki Tagome, Yasuhiro Kondo, Naoyuki Kadoya
  • Patent number: 6917133
    Abstract: An air conditioner comprising a compressor including a compression unit and a permanent magnet rotating electric machine, wherein the permanent magnet rotating electric machine includes a stator, into which concentratively wound armature windings are inserted in such a way as to surround a plurality of teeth formed in a stator core, and a rotor having permanent magnets accommodated into a plurality of permanent magnet inserting holes formed in a rotor core. Each pair of adjacent ones of said permanent magnets is arranged generally in one of a convex V-shaped configuration and a convex U-shaped configuration with respect to a rotor axis, and a substantially V-shaped recess portion is formed between adjacent poles in outer circumferential surface portions of the rotor core.
    Type: Grant
    Filed: February 20, 2003
    Date of Patent: July 12, 2005
    Assignee: Hitachi, Ltd.
    Inventors: Haruo Koharagi, Masaharu Senoh, Keiji Noma, Kohei Ishii, Kazuo Sato, Satoshi Kikuchi, Miyoshi Takahashi, Kouki Yamamoto
  • Patent number: 6876117
    Abstract: 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: Grant
    Filed: September 7, 2004
    Date of Patent: April 5, 2005
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Patent number: 6867526
    Abstract: A bridge (8) in conformity with a tooth opening angle of the stator (1) is provided between a permanent magnet (5) and a permanent magnet (5) in a rotor (4), so that a magnetic flux for a reluctance torque is made to pass an inner side of the permanent magnet (5). An opening angle of each of ribs (7) on both sides of the permanent magnet (5) is set to be equal to or smaller than the teeth interval opening angle and equal to or larger than a half thereof. Thereby, reluctance of the rib (7) against a magnetic flux in a circumferential direction is increased and leakage of the magnetic flux of the permanent magnet (5) is prevented.
    Type: Grant
    Filed: September 4, 2002
    Date of Patent: March 15, 2005
    Assignee: Koyo Seiko Co., Ltd.
    Inventors: Sadaaki Mori, Hirohide Inayama, Atsushi Ishihara, Tomofumi Takahashi, Minoru Kitabayashi, Tetsuo Horie
  • Patent number: 6858968
    Abstract: The conventional slit is symmetrically aligned with respect to the q-axis that is a direction where the magnetic flux is difficult to flow. Because of this, the generated magnetic flux must jump over the slit, whereas its jumping over position being dependent on the rotation of the rotor. This hinders a flow of the magnetic flux. This has caused problems such as making the efficiency worse and increasing the losses. Therefore, at least one pair of slits is constructed on the rotor, which forms the salient pole so as to obtain the d-axis (where the magnetic flux is easy to flow) and the q-axis (where the magnetic flux is difficult to flow). A low magnetic resistance parts having a small magnetic resistance are formed at these slits that are asymmetrically aligned with respect to the q-axis.
    Type: Grant
    Filed: November 26, 2002
    Date of Patent: February 22, 2005
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yoshio Takita, Hitoshi Kawaguchi, Hayato Yoshino
  • Patent number: 6853106
    Abstract: A brushless motor capable of increasing energy density by effective utilization of reluctance torque. The brushless motor comprises a stator (5) and a rotor (1) having a lateral surface opposed to the stator (5). The stator (5) comprises a plurality of radially extending iron cores (10) and a plurality of windings (11) for generating a magnetic field in each iron core (10). The rotor (1) comprises a plurality of permanent magnets (2) and a magnetic field line inducing body disposed between each permanent magnet (2) and the lateral surface.
    Type: Grant
    Filed: May 31, 2001
    Date of Patent: February 8, 2005
    Assignees: Mitsubishi Heavy Industries, Ltd.
    Inventors: Kenji Fujiwara, Akira Nishio, Yoshiki Kato, Masahiro Hirano, Takatoshi Kogure, Tsutomu Baba
  • Patent number: 6822360
    Abstract: A magnetic gap is provided between a permanent magnet of a rotor and an auxiliary magnetic 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: Grant
    Filed: January 9, 2003
    Date of Patent: November 23, 2004
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Publication number: 20040217667
    Abstract: The present invention relates to a rotor assembly for an electrical machine, comprising: a rotor body of generally cylindrical shape having a substantially cylindrical surface configured for facing an air-gap between the rotor assembly and a stator of the electrical machine, and permanent magnets embedded in said rotor body, wherein grooves are formed in said air-gap facing surface for manipulating the distribution of magnetic flux created by said permanent magnets.
    Type: Application
    Filed: January 16, 2004
    Publication date: November 4, 2004
    Inventor: Vladimir Vladimirovich Popov
  • Patent number: 6768238
    Abstract: A rotor for permanent magnet synchronous machines with a reduction in the stray flux transmitted through the rotor shaft includes substantially ring-shaped punched sheet metal plates with a central opening for receiving the rotor shaft, and a plurality of recesses arranged in the circumferential direction, wherein at least two permanent magnets can be inserted in each of the recesses. A corresponding intermediate sheet metal segment is arranged or can be arranged in each of the recesses between the permanent magnets. At least one of the recesses is shaped so as to form an air gap between the surface of the intermediate sheet metal segment that is oriented radially inwardly towards the center and an edge of the recess that is oriented radially outwardly from the center, when the permanent magnets are inserted radially towards the outside. The air gap aids in attenuating the stray flux.
    Type: Grant
    Filed: October 31, 2002
    Date of Patent: July 27, 2004
    Assignee: Siemens Aktiengesellschaft
    Inventors: Axel Knauff, Rolf Vollmer
  • Patent number: 6741010
    Abstract: A rotor disc (14), for use in an electrical machine (10), has at least one circumferential rotor rim (16) mounted thereon. The rotor rim (16) comprises at least one row of alternate magnets (20) and laminated pole pieces (18). The laminations in each pole piece (18) are mounted concentrically on a bolt (22) that extends through the rotor disc (14). A clearance (23) is provided between the laminations in each pole piece (18) and the bolt (22). The clearance (23) insulates the bolt (22) from the laminated pole pieces (18), which are made from a ferromagnetic material such as silicon-iron alloy, to minimize power losses due to eddy currents.
    Type: Grant
    Filed: January 8, 2001
    Date of Patent: May 25, 2004
    Assignee: Rolls Royce PLC
    Inventor: Geoffrey A Wilkin
  • Patent number: 6727623
    Abstract: An interior permanent magnet machine is disclosed that, in one exemplary embodiment, includes a stator defining a number of stator poles, a rotor, a number of permanent magnets positioned within the interior of the rotor and at least two impedance reduction slits associated with each permanent magnet where the impedance reduction slits are positioned radially outward of the permanent magnets. In further embodiments, each impedance reduction slit is positioned such that at least a portion of the slit is within a defined region.
    Type: Grant
    Filed: August 28, 2002
    Date of Patent: April 27, 2004
    Assignee: Emerson Electric Co.
    Inventors: Gary E. Horst, Alan D. Crapo
  • Patent number: 6717314
    Abstract: A high torque density interior permanent magnet machine for use in an appliance is provided that includes a stator assembly defining a plurality of stator teeth, a plurality of concentrated phase windings positioned about the stator teeth, a rotor assembly positioned within the prior bore and a plurality of magnets positioned within the interior of the rotor. Also disclosed in a washing machine including such a machine.
    Type: Grant
    Filed: August 28, 2002
    Date of Patent: April 6, 2004
    Assignee: Emerson Electric Co.
    Inventors: Gary E. Horst, Alan D. Crapo
  • Patent number: 6713923
    Abstract: To provide an orientation device capable of efficiently orientating resinous magnets filled in slits of a rotor core. An orientation device comprising a plurality of permanent magnets 5 disposed at the same intervals as slits 2 in the rotor core 1 with their magnetic poles of the same polarity adjacent to each other, along the outside circumference of a rotor core housing section 4 for housing the rotor core 1, and a plurality of pole pieces 6 disposed between the plurality of permanent magnets 5, wherein the width of the pole piece 6 at the end 6a on the side of the rotor core housing section 4 is no larger than the maximum width &agr; max of an outermost slit 2a of the rotor core 1 between opposite ends thereof.
    Type: Grant
    Filed: July 30, 2002
    Date of Patent: March 30, 2004
    Assignee: Yamaha Hatsudoki Kabushiki Kaisha
    Inventors: Haruyoshi Hino, Shinya Naito
  • Publication number: 20040041486
    Abstract: A rotor for an interior permanent magnet machine that tends to reduce magnet chattering that includes a rotor stack defining at least one magnet retention slot and a permanent magnet positioned within the magnet retention slot, where the magnet retention slot is formed such that movement of the permanent magnet towards at least one end of the slot will tend to cause the magnet to become wedged within the slot.
    Type: Application
    Filed: August 28, 2002
    Publication date: March 4, 2004
    Inventor: Horst E. Gary
  • Patent number: 6664690
    Abstract: For achieving a constant capacity range by way of field weakening of a permanent magnet excited drive the magnetic transverse resistance (Rm) of the rotor plate pack is increased by pole gaps (P1, P2), which are produced by milling into the upper surface (O) of the rotor plate section (L), or are punched into the rotor plate section (L), whereby a covering of the poles of Tp in the range of from 70% to 80% has been shown to be particularly advantageous.
    Type: Grant
    Filed: August 23, 2001
    Date of Patent: December 16, 2003
    Assignee: Siemens Aktiengesellschaft
    Inventor: Gerhard Huth
  • Patent number: 6657350
    Abstract: A permanent magnet type rotating electrical machine characterized by reduced vibration and noise, or improved efficiency. In a permanent magnet type rotating electrical machine comprising a stator 10 provided with concentrated winding and a rotor with permanent magnets 24 embedded in the rotor core 21, induced voltage waveform is improved by formation of two grooves or holes (flux barriers) extending in the axial direction for each magnetic pole on the bridge 25 of the core between the permanent magnet insertion hole 23 and the outer surface of rotor 20 in such a way that they are placed at an equally spaced interval over the entire circumference of the rotor 20.
    Type: Grant
    Filed: September 26, 2001
    Date of Patent: December 2, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Mamoru Kimura, Haruo Koharagi, Hiroyuki Mikami, Miyoshi Takahashi
  • Patent number: 6590312
    Abstract: A rotary electric machine for a hybrid vehicle includes a rotor connected between a vehicle engine and a torque transmission mechanism at the back of the vehicle engine and a stator. The rotor includes an outer rotor portion having an inner surface electro-magnetically connected to the outer surface of the stator, an inner rotor portion having an outer surface electro-magnetically connected to the inner surface of the stator. The stator includes a stator core disposed between the inner rotor portion and the outer rotor portion and a multi-phase winding wound on the stator to be electro-magnetically connected with both the outer and inner rotor portions.
    Type: Grant
    Filed: November 17, 2000
    Date of Patent: July 8, 2003
    Assignee: Denso Corporation
    Inventors: Masahiro Seguchi, Keiichiro Banzai, Sumio Yanase, Shinji Kouda, Shigenori Yoneda
  • Publication number: 20030102757
    Abstract: A magnetic gap is provided between a permanent magnet of a rotor and an auxiliary magnetic 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: Application
    Filed: January 9, 2003
    Publication date: June 5, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Publication number: 20030080642
    Abstract: A bridge (8) in conformity with a tooth opening angle of the stator (1) is provided between a permanent magnet (5) and a permanent magnet (5) in a rotor (4), so that a magnetic flux for a reluctance torque is made to pass an inner side of the permanent magnet (5). An opening angle of each of ribs (7) on both sides of the permanent magnet (5) is set to be equal to or smaller than the teeth interval opening angle and equal to or larger than a half thereof. Thereby, reluctance of the rib (7) against a magnetic flux in a circumferential direction is increased and leakage of the magnetic flux of the permanent magnet (5) is prevented.
    Type: Application
    Filed: September 4, 2002
    Publication date: May 1, 2003
    Applicant: KOYO SEIKO CO., LTD.
    Inventors: Sadaaki Mori, Hirohide Inayama, Atsushi Ishihara, Tomofumi Takahashi, Minoru Kitabayashi, Tetsuo Horie
  • Patent number: 6555940
    Abstract: To decrease torque ripples and cogging torque, a rotor for an electrical motor, an electrical generator, or the like, includes lengths of permanent magnets embedded in a plurality of slit sections in respective layers. In an embodiment having three layers, the permanent magnets have lengths L1, L2 and L3 in order as viewed from the outside circumference side of the rotor core and generate respective total magnetic fluxes of &PHgr;1, &PHgr;2, &PHgr;3, respectively, when the rotor is assembled in a rotary electric device. The lengths have a relation L1<L2<L3, and the magnetic fluxes have a relation &PHgr;1<&PHgr;2<&PHgr;3.
    Type: Grant
    Filed: August 30, 2001
    Date of Patent: April 29, 2003
    Assignee: Yamaha Hatsudoki Kabushiki Kaisha
    Inventors: Shinya Naito, Haruyoshi Hino
  • Patent number: 6528920
    Abstract: At least one groove and two grooves extending toward an axial direction of a rotor and is provided on an outer periphery of a rotor iron core or at least one hole is provided in the rotor iron core. By providing the groove and the two grooves on the outer periphery of the rotor iron core or by providing the hole in the rotor iron core, cogging torque is generated to negate the cogging torque which is generated according to the magnetic fluctuation between the magnetic field of the permanent magnets and a stator. As a result, the overall cogging toque in a permanent magnet type rotary machine is reduced.
    Type: Grant
    Filed: March 14, 2001
    Date of Patent: March 4, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Yutaka Matsunobu, Fumio Tajima, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi
  • Patent number: 6525442
    Abstract: A permanent magnet rotating electric machine that comprises a stator, into which concentratively wound armature windings are inserted in such a way as to surround a plurality of teeth formed in a stator core, and a rotor having permanent magnets accommodated into a plurality of permanent magnet inserting holes formed in a rotor core. In this rotating electric machine, the permanent magnets are convex V-shaped or U-shaped with respect to a rotor axis. Moreover, nearly V-shaped recess portions, each of which is placed between adjacent poles, are formed in outer circumferential surface portions of the rotor core. Thus, torque caused by magnetic flux due to the magnets is increased, while armature reaction magnetic flux generated by an armature current is reduced. Consequently, q-axis inductance is reduced, so that armature current commutation is quickly achieved.
    Type: Grant
    Filed: February 27, 2001
    Date of Patent: February 25, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Haruo Koharagi, Masaharu Senoh, Keiji Noma, Kohei Ishii, Kazuo Sato, Satoshi Kikuchi, Miyoshi Takahashi, Kouki Yamamoto
  • Patent number: 6512317
    Abstract: The present invention relates to a permanent magnet rotor comprising a rotary iron core formed by stacking a plurality of round steel plates, and a plurality of arc-shaped permanent magnets, wherein said individual arc-shaped permanent magnets of alternation poles are provided in the corresponding openings. In particular, the present invention discloses round-cornered permanent magnets by providing round instead of sharp comers at outer perimeter of two adjacent permanent magnets so as to form triangle-shaped regions. Moreover, to prevent said open areas from being filled up, portions of steel plates or holes through steel plates opposite said open areas are removed or created, respectively, so that magnetic flux leakage is minimized and motor performance is elevated.
    Type: Grant
    Filed: December 26, 2000
    Date of Patent: January 28, 2003
    Assignee: Industrial Technology Research Institute
    Inventors: Ching-Feng Lai, Yu-Choung Chang, Tse-Liang Hsiao, Chun-Chung Yang, Kun-I Liang, Ann Huang