Combined Permanent And Electromagnet Patents (Class 310/181)
  • Patent number: 7317273
    Abstract: An electromagnetic actuator includes a cylindrical stator made of a permanent magnet and having annular end faces magnetized to plural magnetic poles, a coil securely disposed in a hollow portion of the stator via a bobbin on which the coil is wound and which is fixed to the stator's hollow portion, a rotary shaft put through the coil in the direction of the center axis thereof in such a way as to be rotatably supported at the bobbin, and a rotor of a soft magnetic material provided in such a way as to rotate together with the rotary shaft and having plural rotor arms radially extending from both end portions of the rotary shaft and facing the respective annular end faces of the stator.
    Type: Grant
    Filed: October 27, 2004
    Date of Patent: January 8, 2008
    Assignee: SEIKO Precision Inc.
    Inventor: Shigeru Yanagisawa
  • Publication number: 20070296312
    Abstract: A drive apparatus having a shortened axial dimension. First and second magnets are each formed into a semi-cylindrical shape and each provided with a magnetized pattern portion. A rotor yoke includes a shaft portion and a magnetic pole portion facing magnetized surfaces of the magnets. First and second stator yokes are each disposed to cooperate with the rotor yoke to sandwich therebetween a part of the first or second magnet where the magnetized pattern portion is formed. First and second coils each magnetize a part of the magnetic pole portion of the rotor yoke which faces the first or second stator yoke.
    Type: Application
    Filed: June 22, 2007
    Publication date: December 27, 2007
    Applicant: CANON KABUSHIKI KAISHA
    Inventor: Hiromu YASUDA
  • Publication number: 20070278895
    Abstract: In a Lundell type rotor core of a rotor in a vehicular AC generator, each interposing magnet is supported at a base part of each claw-shaped magnetic pole part in an axial direction of the rotor. This configuration prevents the transmission of deformation at a front end part of each claw-shaped magnetic pole part to the interposing magnet during rotation of the rotor at high rotation speed.
    Type: Application
    Filed: May 21, 2007
    Publication date: December 6, 2007
    Applicant: DENSO CORPORATION
    Inventor: Shin Kusase
  • Patent number: 7265471
    Abstract: Energy is generated by an apparatus and process which utilize magnetic forces to move a rotor in a circular direction to turn a rotor shaft. This apparatus and process convert magnetic energy into mechanical force or electrical energy.
    Type: Grant
    Filed: October 7, 2005
    Date of Patent: September 4, 2007
    Assignee: M International, LLC
    Inventor: Harry Paul Sprain
  • Patent number: 7224091
    Abstract: A stepping motor includes a hollow cylindrical fixed yoke; a magnet disposed coaxially with the fixed yoke and divided into sections in the circumferential direction, the sections being alternately magnetized; a first coil and a second coil coaxially fixed to the fixed yoke; a first rotational yoke facing a magnetized surface of the magnet and excited by the first coil; a second rotational yoke facing the magnetized surface of the magnet and excited by the second coil; and bearing units formed in bobbins for supporting a rotor including the first rotational yoke, a connecting member, and the second rotational yoke such that the rotor is rotatable with respect to the fixed yoke.
    Type: Grant
    Filed: August 30, 2005
    Date of Patent: May 29, 2007
    Assignee: Canon Kabushiki Kaisha
    Inventor: Hiromu Yasuda
  • Patent number: 7129611
    Abstract: 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: Grant
    Filed: September 23, 2003
    Date of Patent: October 31, 2006
    Assignee: UT-Battelle LLC
    Inventor: John S. Hsu
  • Patent number: 7112907
    Abstract: A stator and armature assembly 12 is provided for a permanent magnet DC motor. The assembly includes an armature 13 having a lamination core 14 and windings 15, and a stator structure 16 associated with the armature. The armature is constructed and arranged to rotate with respect to the stator structure. The stator structure includes at least one permanent magnet 22 providing a certain flux, and at least one wound core structure 17 having a core 18 and a coil 19 wound about the core so as to define an alternate pole with respect to the permanent magnet. When current to the coil is controlled, flux of the stator structure 16 can be increased or decreased relative to the certain flux. In this way a motor can operate at different speeds.
    Type: Grant
    Filed: May 11, 2004
    Date of Patent: September 26, 2006
    Assignee: Siemens VDO Automotive Inc.
    Inventors: Andrew Lakerdas, Attila Simofi-Ilyes, John E. Makaran, Corneliu Dragoi, Peter A. Kershaw, Martin Volkening
  • Patent number: 7075200
    Abstract: Rotating-force transmission means is omitted by mounting permanent magnet plates directly to a rotational body which is rotated by magnetic repulsive force, thereby achieving a high-efficiency compact low-cost direct-driven magnetic rotating apparatus.
    Type: Grant
    Filed: August 25, 2004
    Date of Patent: July 11, 2006
    Inventors: Kohei Minato, Nobue Minato
  • Patent number: 7064526
    Abstract: A permanent magnet starter/generator subsystem configured in a fault tolerant architecture is described herein for small engine applications. The system allows for lighter system weight, improved system reliability, higher performance capability and reduced maintenance.
    Type: Grant
    Filed: April 23, 2004
    Date of Patent: June 20, 2006
    Assignee: Astronics Advanced Electronic Systems Corp.
    Inventor: Stanley C. Patterson
  • Patent number: 7023122
    Abstract: The first magnet (9) is set free to tumble within a tumbling chamber (10). A coil (11) wound around the out surface of the tumbling chamber (10). The two ends of the coil (11) are connected to the terminals of an LED (light emitting diode) (3). There may be some arbitrary, relative motion between the first magnet (9) and the second magnet (2). The magnets depicted with dotted lines represent alternative, relative motions of the second magnet (2) with respect to the first magnet (9). As the first magnet (9) and the second magnet (2) pass close to one another, the mutual interaction of the magnetic fields is sufficient to cause the first magnet (9) to tumble in the tumbling chamber (10). As the first magnet (9) tumbles in the tumbling chamber (10), a varying magnetic filed flux is effected through the coil (11) and a corresponding electric current flows through the coil (11) thus illuminating the LED 3.
    Type: Grant
    Filed: November 24, 2003
    Date of Patent: April 4, 2006
    Inventor: Qin Gang
  • Patent number: 6995490
    Abstract: A stator and armature assembly 12 is provided for a permanent magnet DC motor. The assembly includes an armature 13 having a lamination core 14 and windings 15, and a stator structure 16 associated with the armature. The armature is constructed and arranged to rotate with respect to the stator structure. The stator structure includes at least one permanent magnet 22 providing a certain flux, and at least one wound core structure 17 having a core 18 and a coil 19 wound about the core so as to define an alternate pole with respect to the permanent magnet. When current to the coil is controlled, flux of the stator structure 16 can be increased or decreased relative to the certain flux. In this way a motor can operate at different speeds.
    Type: Grant
    Filed: June 6, 2005
    Date of Patent: February 7, 2006
    Assignee: Siemens VDO Automotive Inc.
    Inventors: Andrew Lakerdas, Attila Simofi-Ilyes, John E. Makaran, Corneliu Dragoi, Peter A. Kershaw, Martin Volkening
  • Patent number: 6989619
    Abstract: 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). Improvements of a laminated rotor, an end pole structure, and an arrangement of the PM elements for providing an arrangement of the flux paths from the auxiliary field coil assemblies are also disclosed.
    Type: Grant
    Filed: May 18, 2004
    Date of Patent: January 24, 2006
    Assignee: UT-Battelle LLC
    Inventor: John S. Hsu
  • Patent number: 6975050
    Abstract: A system and method for reducing the cost of producing a brushless DC motor is presented. The brushless DC motor provides higher power density and efficiency with an increased tool run time. The brushless DC motor includes a rotor assembly that has an unmagnetized permanent magnet affixed to a shaft. The permanent magnet remains unmagnetized until the motor is partially assembled. A plurality of coils for producing a magnetic field are wound about the rotor assembly. The coils include end turns that enclose the rotor assembly such that the rotor assembly is not removable. Since the windings are wound with the rotor assembly already enclosed, the windings do not require large end coils to allow subsequent insertion of the rotor. Minimizing the end coils reduces the length of wire required per turn, thereby reducing the resistance of the winding.
    Type: Grant
    Filed: January 4, 2001
    Date of Patent: December 13, 2005
    Assignee: Black & Decker Inc.
    Inventors: Aris C. Cleanthous, Bhauprasad V. Gorti, Michael J. Weaver, Christopher R. Yahnker, Richard T. Walter
  • Patent number: 6972504
    Abstract: 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, and preferably two, DC excitation assemblies (23, 24) are positioned at opposite ends of the rotor (20) to define secondary air gaps (21, 22). Portions of PM material (14a, 14b) are provided as boundaries separating the rotor pole portions (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 the pole portions prior to reaching the primary air gap (20). The portions of PM material (14a, 14b) are spaced from each other so as to include reluctance poles (15) of ferromagnetic material between the PM poles (12a, 12b) to interact with the AC flux in the primary-air gap (20).
    Type: Grant
    Filed: December 21, 2004
    Date of Patent: December 6, 2005
    Assignee: UT-Battelle LLC
    Inventor: John S. Hsu
  • Patent number: 6967417
    Abstract: An electric generator is disclosed having a high efficiency over wide ranges in rotor speed and power output requirements. Output voltage control is achieved by providing the power output windings with variable adjustment. This variable adjustment determines the number of turns that are used for the power output on the power output windings themselves. When excess voltage is generated, turns used on the power output windings are reduced thereby reducing output voltage and increasing efficiency by lowering the power output winding resistance. When the voltage generated is low, more turns on the power output windings are activated thereby increasing the voltage of the generator itself. This voltage control occurs prior to any voltage modification outside of the generator. A sensor and feedback mechanism is used to automatically adjust the power output windings thereby attaining maximum efficiency at the desired voltage and power level.
    Type: Grant
    Filed: January 29, 2003
    Date of Patent: November 22, 2005
  • Patent number: 6960858
    Abstract: A motor which uses a permanent magnet is provided in which output thrust is improved by increasing a magnetic saturation limit and preventing reduction in magnetic flux and generation of heat is reduced by inhibiting generation of an eddy current in a magnetic pole. An N magnetic pole is formed such that its width increases as the distance from a stator increases on a side of an N pole magnetic yoke and an S magnetic pole is formed such that its width increases as the distance from the stator increases on a side of an S pole magnetic yoke. With this structure, a saturation limit of magnetic flux at an entrance of yoke which is a connection section between the N magnetic pole and the N pole magnetic yoke is increased and motor thrust is improved.
    Type: Grant
    Filed: May 12, 2004
    Date of Patent: November 1, 2005
    Assignee: Okuma Corporation
    Inventor: Yoichi Kawai
  • Patent number: 6954019
    Abstract: Energy is generated by an apparatus and process which utilize magnetic forces to move a rotor in a circular direction to turn a rotor shaft. This apparatus and process convert magnetic energy into mechanical force or electrical energy.
    Type: Grant
    Filed: November 6, 2002
    Date of Patent: October 11, 2005
    Assignee: M International, LLC
    Inventor: Harry Paul Sprain
  • Patent number: 6933818
    Abstract: A torque motor may include a rotor having at least two magnets disposed thereon, and a stator having a core and at least one coil. The magnets are arranged and constructed so that the outer surfaces thereof alternately have a N pole and a S pole. The magnets cover the rotor over an angle of less than 360 degrees. The core has a first and second magnetic pole elements. The magnetic pole elements are arranged and constructed such that an angle defined between a first straight line passing through a center of the first magnetic element and a center of rotation of the rotor and a second straight line passing through a center of the second magnetic element and the center of rotation of the rotor is less than 180 degrees.
    Type: Grant
    Filed: June 24, 2004
    Date of Patent: August 23, 2005
    Assignee: Aisan Kogyo Kabushiki Kaisha
    Inventor: Susumu Kaneshige
  • Patent number: 6906490
    Abstract: A switched reluctance drive is operated as a generator on a high voltage supply which has no long-term energy storage capability. A low voltage supply is used to start the generator through the use of a dedicated priming winding, which provides sufficient energy to allow the generator to build up charge in DC link capacitor(s). Once sufficient charge has built up, the priming winding is de-energized and the generator continues in a steady-state operation.
    Type: Grant
    Filed: July 8, 2003
    Date of Patent: June 14, 2005
    Assignee: Switched Reluctance Drives Limited
    Inventor: Michael James Turner
  • Patent number: 6885121
    Abstract: The flux densities formed by plural electromagnet poles M1 to M12 which are arranged at a predetermined interval in a circumferential direction of a rotary body 1 at the same position in an axial direction of the rotary body 1 are gradually changed in the circumferential direction of the rotary body. Even if there is a difference between the maximum value of the flux density and the minimum value, the change of the flux densities between the adjacent electromagnet poles is small and smooth. Accordingly satisfactory detective sensitivity and detection results can be obtained.
    Type: Grant
    Filed: July 4, 2002
    Date of Patent: April 26, 2005
    Assignee: Sankyo Seiki Mfg. Co. Ltd.
    Inventors: Yohji Okada, Hideki Kanebako, Keisuke Abe
  • Patent number: 6873077
    Abstract: Cup-shaped magnet for electric motors having two face surfaces, two lateral surface, and two top surfaces, which are curving between the face surfaces along the lateral surfaces, whereby the lateral faces are chamfered in a v-shape.
    Type: Grant
    Filed: September 23, 2002
    Date of Patent: March 29, 2005
    Assignee: Vacuumschmelze GmbH & Co. KG
    Inventor: Frank Jurisch
  • Patent number: 6864608
    Abstract: Disclosed is a brushless generator with permanent magnets, which provides high-speed operation, simple maintenance, lightweight, and stable power. The brushless generator with permanent magnets including a main generator with a stator and a rotor; and an auxiliary generator having a stator made of a hollow stator core and a coil wound around the stator core, and a rotor made of a rotor core rotating within the stator core and a coil wound around the rotor core, where wedges and grooves are formed alternatively on the inner portion of the stator core of the auxiliary generator, and permanent magnets are embedded in the body of the grooves and the coil is wound around the body of the grooves. Accordingly, without the use of a brush, a rated load voltage is generated from the permanent magnets of the auxiliary generator, and voltage variations due to load variations are controlled by the windings of the auxiliary generator.
    Type: Grant
    Filed: July 31, 2002
    Date of Patent: March 8, 2005
    Assignee: Korea Electrotechnology Research Institute
    Inventors: Do Hyun Kang, Yeon Ho Jeong
  • Patent number: 6844656
    Abstract: This invention relates to an electric multiple motor/generator with axial magnetic flux. Thus a generator/motor or electrical machine in which a magnetic flux path through one or more pole legs or pole cores surrounded by current windings or coils is provided. This allows a high density of the magnetic flux to be passed through the pole legs or cores, which results in a low consumption of material for the pole legs or pole cores compared with prior art machines, where for example a large stator diameter may be needed in order to conduct a high magnetic flux. Additionally the generator/motor or electrical machine is very efficient both at a low and a high number of revolutions. According to another aspect of the invention a multiple phase output without enlarging the diameter of the generator is provided.
    Type: Grant
    Filed: February 9, 2000
    Date of Patent: January 18, 2005
    Assignee: NEG Micon Control Systems A/S
    Inventors: Kim Dam Larsen, Peter Rasmussen, Uffe Dam Larsen
  • Patent number: 6806599
    Abstract: To simplify the design of a rotary actuator, in particular for an “R”-type waveguide switch, having a permanently magnetized rotor and a plurality of stator windings surrounding the rotor in a rim-like fashion, for generating magnetic fields which place the rotor in one of a first plurality of positions, it is proposed to finish the actuator with elements for exerting a corrective torque on the rotor, the elements placing the rotor, in the currentless state of the stator windings, in a target position of a second plurality of positions, each position of the first plurality having assigned to it a target position.
    Type: Grant
    Filed: December 23, 2001
    Date of Patent: October 19, 2004
    Assignee: Robert Bosch GmbH
    Inventor: Eckart Hettlage
  • Patent number: 6806609
    Abstract: A single phase induction motor and a compressor utilizing the single phase induction motor wherein the motor has a stator having a plurality of slots; a rotor being rotated by a magnetic field generated by an electric force between the stator and the rotor; and a main winding and a sub winding wound through the plurality of slots of the stator to form a revolving magnetic field of the rotor. The main winding and the sub winding form a centralized type of winding structure so that the main winding and the sub winding are wound in an alternate pattern via adjacent slots. Since the centralized winding structure of the main winding and the sub winding which are wound through the slots of the stator, the coil end is greatly reduced, and as a result, the material costs and copper loss can be greatly reduced. Further, the main winding and the sub winding, which are wound through the slots of the stator, do not protrude from opposite sides of the stator too much.
    Type: Grant
    Filed: May 28, 2002
    Date of Patent: October 19, 2004
    Assignee: Samsung Gwangju Electronics Co., Ltd.
    Inventor: Hyun-rok Cha
  • Patent number: 6806610
    Abstract: The invention provides a magnetic motor wherein a plurality of rotor magnets are positioned along a rotor which is mounted to a shaft. A plurality of drive magnets are movably positioned generally adjacent to the rotor magnets. Relative motion of the drive magnets into and out of juxtaposed positions with the rotor magnets controls relative torque of the shaft. The drive magnets are electrically pulsed through a timing assembly.
    Type: Grant
    Filed: February 27, 2002
    Date of Patent: October 19, 2004
    Inventor: Monte Dilliner
  • Publication number: 20040189132
    Abstract: A modular assembly for an electromagnetic machine is disclosed. The modular assembly includes a rotor assembly and a flux controlling assembly. The rotor assembly has a shaft and has a plurality of rotor laminations mounted on the shaft. The rotor laminations define at least four salient rotor poles. At least one permanent magnet is embedded in each of at least two of the salient rotor poles. The flux assembly has a stationary coil disposing about the shaft for controlling flux of the disclosed machine. The flux assembly also has a cage supported on the rotor assembly for transferring flux between the at least two salient rotor poles with embedded magnets and the coil. In one embodiment, a support member is mounted on the shaft and supports the cage thereon. In another embodiment, a support member is connected between the cage and the at least two rotor poles with embedded magnets.
    Type: Application
    Filed: March 27, 2003
    Publication date: September 30, 2004
    Applicant: Emerson Electric Company
    Inventor: Gary E. Horst
  • Publication number: 20040178696
    Abstract: (Subject
    Type: Application
    Filed: April 23, 2003
    Publication date: September 16, 2004
    Applicant: HITACHI, LTD.
    Inventors: Susumu Tajima, Shinji Yamazaki, Wasei Horioka, Masahiko Honma
  • Publication number: 20040178691
    Abstract: To reduce the stator size and realize a compact, high-efficiency and high-output rotary electric machine.
    Type: Application
    Filed: August 15, 2003
    Publication date: September 16, 2004
    Applicant: HITACHI, LTD.
    Inventors: Kazuaki Sanada, Takashi Matsunobu, Shigeo Amagi, Mamoru Kimura
  • Patent number: 6792335
    Abstract: A mobile device for traversing a ferromagnetic surface. The device includes a frame and at least one surface contacting device attached to the frame. The device also includes a Halbach magnet array attached to the frame, wherein the Halbach magnet array provides a magnetic force to maintain the surface contacting device substantially into contact with the ferromagnetic surface.
    Type: Grant
    Filed: May 23, 2002
    Date of Patent: September 14, 2004
    Assignee: Carnegie Mellon University
    Inventors: William P. Ross, James F. Hoburg, Christopher Fromme, John Bares, Mark DeLouis
  • Patent number: 6791225
    Abstract: The invention relates to a flywheel magneto generator having a rotor assembly and a stator assembly. The rotor assembly includes a non-ferromagnetic flywheel and a plurality of magnetic poles that are positioned in spaced relationship around the circumference of the flywheel. The stator assembly includes an E-shaped core with a single magnet mounted on the center leg and coils associated with at least the outer legs. The poles and core may be formed of a bonded iron material. The poles may be joined to the flywheel by press fitting or integral molding, among other methods.
    Type: Grant
    Filed: February 20, 2003
    Date of Patent: September 14, 2004
    Assignee: Magnequench, Inc.
    Inventors: Peter Campbell, David Johnston Miller
  • Patent number: 6787958
    Abstract: An electrical motor or generator comprises a rotor 79 without windings, a stator 78 having armature windings comprising at least two coils A1, A2 having active portions positioned within armature winding slots 81 in a stator iron, and field windings F having active portions positioned within field winding slots 80 in the stator iron. An electronic control circuit is provided for controlling the currents in the coils A1, A2 in synchronism with rotation of the rotor such that periods in which a magnetomotive force is generated in one direction by current flow in one of the coils alternate with periods in which a magnetomotive force is generated in the opposite direction by current flow in another of the coils. The armature winding slots and the field winding slots are equal in number and alternate with one another in the stator iron.
    Type: Grant
    Filed: April 22, 2002
    Date of Patent: September 7, 2004
    Assignees: Black & Decker Inc., University of Warwick
    Inventor: Richard Thomas Walter
  • Patent number: 6784585
    Abstract: A hybrid synchronous machine includes a cylindrical element having slots; excitation windings situated in at least some of the slots; and permanent magnets situated in at least some of the slots. For a hybrid salient pole machine 16 a cylindrical element has salient poles with excitation windings situated around the salient poles and permanent magnets supported by the salient poles.
    Type: Grant
    Filed: November 18, 2002
    Date of Patent: August 31, 2004
    Assignee: General Electric Company
    Inventors: Manoj Ramprasad Shah, Gerald Burt Kliman, Madabushi Venkata Krishnama Chari
  • Patent number: 6784586
    Abstract: The invention relates to a rotating electric machine, especially an alternator or alternator/starter for motor vehicles, including a stator surrounding a rotor (10) equipped with a pack of metal plates, a gap between the stator and the rotor, permanent magnets integrated into the rotor and excitation coils (14) integrated into the rotor, in which the excitation coils are wound around salient poles (1310) cut out in the pack of metal plates of the rotor, and the permanent magnets are accommodated in housings (13110) formed in the pack of plates of the rotor and open towards the periphery of the rotor, characterized in that the housings (13110) are closed axially at each of their ends by a non-magnetic retaining piece (13) equipped with a part intended to come into abutment with the magnets, and in that the retaining piece features recesses for accommodations [sic] of the buns of the excitation coils (14).
    Type: Grant
    Filed: August 22, 2002
    Date of Patent: August 31, 2004
    Assignee: Valeo Equipments Electriques Moteur
    Inventor: Antoine Dokou Akemakou
  • Patent number: 6777838
    Abstract: A method of increasing the power output of existing permanent magnet motors along with apparatus is disclosed. Increased power output is achieved by more completely utilizing the magnetic field of motor permanent magnets during running. The apparatus is external to the motor and therefore eliminates the need for modifications to the motor itself. The method involves providing a source of power to a permanent magnet motor which is capable of demagnetizing the motor permanent magnets at stall, and reducing the power at start up to a level sufficient to prevent demagnetization. Full power to the motor is provided when the motor speed reaches a level sufficient to prevent demagnetization of the permanent magnets.
    Type: Grant
    Filed: September 26, 2002
    Date of Patent: August 17, 2004
  • Patent number: 6777842
    Abstract: Permanent magnet machines including doubly salient machines having one or more permanent magnets located at least partly and preferably entirely within the stator teeth, thereby avoiding weakening of the stator structure while reducing acoustic noise. The magnets may be located in only a subset of the stator teeth, thereby lowering magnet material and manufacturing costs, and all such magnets may have north poles directed toward an interior of the machine, resulting in reduced cogging and negative torques with improved torque densities. The permanent magnets may also extend within the stator teeth on an angle or diagonal, thereby allowing use of magnets which are wider than the teeth themselves to produce greater flux. Further, a magnetizing device having a single coil may be used to simultaneously magnetize all the stator magnets with a common polarity.
    Type: Grant
    Filed: December 28, 2001
    Date of Patent: August 17, 2004
    Assignee: Emerson Electric Co.
    Inventor: Gary E. Horst
  • Patent number: 6756870
    Abstract: A composite magnet has an iron core, a coil around the iron core, and a permanent magnet in the iron core. A first eddy current retarder includes a brake drum with a rotatable shaft, and a stationary magnet unit inside the inner peripheral surface of the brake drum and having an annular base portion, iron core portions, a support member having magnetic pole pieces at the ends of the iron core portions and opposed to the brake drum, electromagnets, and a permanent magnet in each of the iron core portions with its magnetic pole surface directed in the radial direction. A second eddy current retarder includes a stationary brake drum, an annular magnet support member coupled to a rotatable shaft and inside the inner peripheral surface of the brake drum, and magnets outside the magnet support member and opposed to the surface of the brake drum.
    Type: Grant
    Filed: September 18, 2001
    Date of Patent: June 29, 2004
    Assignee: Isuzu Motors Limited
    Inventor: Tohru Kuwahara
  • Patent number: 6750629
    Abstract: A motor driving system for driving an induction motor with a rotation frequency detector. The induction motor drives a load, and the rotation frequency detector detects a rotation frequency of the induction motor. The motor driving system includes a variable speed driving unit and an inverter control unit. The variable speed driving unit is connected to the induction motor and has a capacitance at output. The variable speed driving unit rectifies first 3-phase AC power to produce DC power, and converts the DC power into second 3-phase AC power with a frequency, and drives the induction motor with the second 3-phase AC power. The inverter control unit generates a frequency instruction and a temporary current instruction based on the detected rotation frequency and a rotation frequency instruction at least.
    Type: Grant
    Filed: November 20, 2001
    Date of Patent: June 15, 2004
    Assignee: Mitsubishi Heavy Industries, Ltd.
    Inventors: Tetsuro Shigemizu, Mitsuyuki Nonaka, Yoshio Kayuki, Noriyuki Akasaka, Osamu Kawabata, Hisanobu Shinoda
  • Patent number: 6727632
    Abstract: A flat rotary electric machine to be mounted in a vehicle engine includes an annular stator core with a plurality of teeth and an armature winding and a field unit including a gutter-like field core having a pair of coaxial cylindrical core members. A plurality of permanent magnets are disposed on the cylindrical core members and an annular field coil disposed between the cylindrical core members. Each of the cylindrical core members has a plurality of magnet-conductive salient magnetic poles disposed between the permanent magnets, the permanent magnets are magnetized so that all the magnetic flux thereof can cross the stator through the teeth in the same direction.
    Type: Grant
    Filed: November 18, 2002
    Date of Patent: April 27, 2004
    Assignee: Denso Corporation
    Inventor: Shin Kusase
  • Patent number: 6707212
    Abstract: The present invention relates to an electrical machine which has one or several stators (2) edified by one or several statorpackages (21) that consists of one or several statorsections (22). The core (23) of the statorpackage is arranged to cooperate with a coil (24) which winding axis (2) of the machine to obtain axially directed magnetic flux. Further, the machine comprises one or several rotordiscs (11) that are arranged on the rotary axis (2).
    Type: Grant
    Filed: November 22, 2002
    Date of Patent: March 16, 2004
    Inventor: Gustaf Bergmark
  • Patent number: 6707226
    Abstract: A rotor of an AC generator includes a field coil, a pole core having a plurality of claw poles disposed in the circumferential direction to enclose the field coil to provide a plurality of magnetic fields when the field coil is energized and a cylindrical permanent magnet disposed inside the plurality of claw poles to supplement the plurality of magnetic fields. The cylindrical permanent magnet is easy to orient magnetic character so that strong magnetic field can be provided at a low cost.
    Type: Grant
    Filed: October 24, 2001
    Date of Patent: March 16, 2004
    Assignee: Denso Corporation
    Inventor: Atsushi Umeda
  • Patent number: 6707213
    Abstract: A DC motor has a stator that is constituted as a hybrid magnet. The stator has a plurality of electromagnets and permanent magnets that are alternately arranged in the circumferential direction of the stator. Fixed cores of the electromagnets have pole cores that have an approximately arched cross-sectional shape. When direct current is supplied to fixed coils, the pole cores are alternately magnetized to be N- and S-poles in the circumferential direction of the stator. The permanent magnets are anisotropic magnets. The inner surface of the permanent magnet includes a first portion that is arranged in one of both sides in the circumferential direction and magnetized to be an S-pole and a second portion that is arranged in the other of both sides in the circumferential direction and magnetized to be an N-pole. The first portion contacts the pole core that is magnetized to be an S-pole and the second portion contacts the pole core that is magnetized to be an N-pole.
    Type: Grant
    Filed: April 4, 2003
    Date of Patent: March 16, 2004
    Assignee: ASMO Co., Ltd.
    Inventor: Kazuhiro Fujita
  • Patent number: 6703746
    Abstract: An electric traction motor for a vehicle including a housing, a wound stator field located in the housing, a rotor magnetically interacting with the wound stator field, high energy magnets configured in the rotor, and low energy magnets configured in the rotor.
    Type: Grant
    Filed: March 1, 2002
    Date of Patent: March 9, 2004
    Assignee: General Motors Corporation
    Inventors: Francois J. Biais, Khwaja M. Rahman
  • Patent number: 6703735
    Abstract: An active magnetic thrust bearing, acting on only a single axial side of a rotor, while also having an efficient permanent magnet bias for linearized and highly amplified control, uses two concentric ring poles that axially face a ferromagnetic axial surface of the rotor, creating two annular axial air gaps. A permanent magnet in the stator drives a bias flux through a first path including two radially spaced concentric ring poles and their air gaps, and an annular region of the rotor axially aligned between the two ring poles. The permanent magnet also drives flux through a second high-reluctance flux path in the stator, by-passing the rotor. An electromagnetic coil in the stator drives a control flux in a circuit including the second path, both ring poles and axial air gaps, and the shunt. The bias and control fluxes are therefore superposed in the axial air gaps for amplified response.
    Type: Grant
    Filed: November 2, 2001
    Date of Patent: March 9, 2004
    Assignee: Indigo Energy, Inc.
    Inventor: Christopher W. Gabrys
  • Publication number: 20040041489
    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 interior bore and a plurality of magnets positioned within the interior of the rotor. Also disclosed in a washing machine including such a machine.
    Type: Application
    Filed: August 28, 2002
    Publication date: March 4, 2004
    Inventors: Gary E. Horst, Alan D. Crapo
  • Patent number: 6700297
    Abstract: A superconducting PM machine has a stator, a rotor and a stationary excitation source without the need of a ferromagnetic frame which is cryogenically cooled for operation in the superconducting state. PM material is placed between poles on the rotor to prevent leakage or diffusion of secondary flux before reaching the main air gap, or to divert PM flux where it is desired to weaken flux in the main air gap. The PM material provides hop-along capability for the machine in the event of a fault condition.
    Type: Grant
    Filed: January 9, 2003
    Date of Patent: March 2, 2004
    Assignee: UT-Battelle, LLC
    Inventors: John S. Hsu, S. William Schwenterly
  • Patent number: 6700272
    Abstract: A reluctance motor with a stator (1) which has a three-phase current stator winding for generating a rotary magnetic field and a rotor (3) which is located on the shaft (2) and which is made primarily of a ferromagnetic material. The rotor is formed of a predetermined number of angular regions of the same peripheral angle which adjoin one another in a circumferential direction and preferably have at least one pair of flux guidance regions (10, 11) facing the stator (1), with flux guidance properties which differ in the main direction of the rotary field.
    Type: Grant
    Filed: July 11, 2000
    Date of Patent: March 2, 2004
    Assignee: EMF 97 Elektro-Maschinen-Vertrieb-Magnettechnik- und Forschungs GmbH
    Inventor: Juergen Lindner
  • Patent number: 6674205
    Abstract: A method and apparatus for fabricating a rotor for an electric traction motor including forming cavities in the rotor, injecting magnetic material in a portion of the cavities, configuring an electrical winding in a portion of the cavities, and post-magnetizing the magnetic material.
    Type: Grant
    Filed: May 7, 2002
    Date of Patent: January 6, 2004
    Assignee: General Motors Corporation
    Inventors: Francois J. Biais, Khwaja M. Rahman
  • Publication number: 20030189385
    Abstract: A DC motor has a stator that is constituted as a hybrid magnet. The stator has a plurality of electromagnets and permanent magnets that are alternately arranged in the circumferential direction of the stator. Fixed cores of the electromagnets have pole cores that have an approximately arched cross-sectional shape. When direct current is supplied to fixed coils, the pole cores are alternately magnetized to be N- and S-poles in the circumferential direction of the stator. The permanent magnets are anisotropic magnets. The inner surface of the permanent magnet includes a first portion that is arranged in one of both sides in the circumferential direction and magnetized to be an S-pole and a second portion that is arranged in the other of both sides in the circumferential direction and magnetized to be an N-pole. The first portion contacts the pole core that is magnetized to be an S-pole and the second portion contacts the pole core that is magnetized to be an N-pole.
    Type: Application
    Filed: April 4, 2003
    Publication date: October 9, 2003
    Applicant: ASMO CO., LTD.
    Inventor: Kazuhiro Fujita
  • Publication number: 20030178909
    Abstract: A rotary electric machine is composed of an armature core, an armature winding, a rotor core disposed opposite said armature core, a rotary magnetic-flux source for supplying first magnetic flux to the rotor core, a frame for supporting the armature core and the rotor core and a stationary magnetic flux source, fixed to the frame, for supplying second magnetic flux to the rotor core in a direction to supplement the first magnetic flux.
    Type: Application
    Filed: March 19, 2003
    Publication date: September 25, 2003
    Applicant: Denso Corporation
    Inventors: Shin Kusase, Takuzou Mukai