Skewed Patents (Class 310/156.47)
  • Publication number: 20040251762
    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: Application
    Filed: June 14, 2004
    Publication date: December 16, 2004
    Applicant: DUCATI ENERGIA S.P.A.
    Inventors: Gianni Regazzi, Manuel Cocchi
  • Publication number: 20040245880
    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: Application
    Filed: June 4, 2003
    Publication date: December 9, 2004
    Inventor: Feng Liang
  • Patent number: 6817507
    Abstract: A capstan motor for a magnetic recording and reproducing apparatus includes a stator having a coil disposed on outer peripheral direction thereof, and a rotor having a magnet to correspond to coil and rotated by an electromagnetic interaction between the coil and the magnet. A capstan shaft is rotated integrally with the rotor, is fixed on the rotor and installed so that one side of the capstan shaft is cohered with a pinch roller taking a tape therebetween to drive the tape with the pinch roller. The magnet has a predetermined shape and is provided to apply magnetic force of the magnet eccentrically for an electromagnetic force generated on the coil so that a predetermined thrust can be applied to the capstan shaft toward one direction between upper and lower directions of the shaft direction.
    Type: Grant
    Filed: October 17, 2002
    Date of Patent: November 16, 2004
    Assignee: LG Electronics Inc.
    Inventor: Eui-Jung Yeon
  • Publication number: 20040217665
    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: Application
    Filed: February 3, 2004
    Publication date: November 4, 2004
    Applicant: Minebea Co., Ltd.
    Inventor: Helmut Hans
  • Publication number: 20040207280
    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: Application
    Filed: April 21, 2003
    Publication date: October 21, 2004
    Applicant: Eaton Corporation
    Inventors: Jian Luo, Jose Antonio Hernandez, Maria Hernandez, John Laskowsky
  • Publication number: 20040164635
    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: Application
    Filed: February 9, 2004
    Publication date: August 26, 2004
    Applicant: KABUSHIKI KAISHA MORIC
    Inventors: Hideaki Takahashi, Koichi Sano
  • Publication number: 20040155547
    Abstract: A motor for reducing torque ripple includes a shaft having a shaft axis, a rotor positioned about the shaft, a first magnet ring positioned on the rotor, the first magnet ring having magnets each occupying a magnet angle &egr; on the rotor, and a second magnet ring positioned on the rotor, the second magnet ring having magnets each occupying a magnet angle &egr; on the rotor, wherein the second magnet ring is shifted a non-zero number of degrees relative to the first magnet ring and wherein ends of each magnet within the second magnet ring are located at different angular positions than ends of each magnet within the first magnet ring relative to the shaft axis of the shaft. The magnet angle &egr; is preferably an optimal magnet angle for minimizing cogging torque and line to line back emf harmonics.
    Type: Application
    Filed: February 10, 2003
    Publication date: August 12, 2004
    Inventors: Mohammad S. Islam, Tomy Sebastian
  • Publication number: 20040124728
    Abstract: A permanent-magnet rotating machine includes a rotor having a rotor core carrying on its curved outer surface multiple permanent magnets arranged in two rows along an axial direction in such a manner that 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) &thgr;e, and a stator having a cylindrical stator core in which the rotor is disposed, the stator core being provided with stator coils for producing a rotating magnetic field for rotating the rotor. A lower limit of the row-to-row skew angle &thgr;e is set at a value larger than 30 degrees (electrical angle).
    Type: Application
    Filed: October 9, 2003
    Publication date: July 1, 2004
    Applicant: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Shinichi Yamaguchi, Haruyuki Kometani, Tomohiro Kikuchi, Takashi Miyazaki
  • Patent number: 6737778
    Abstract: A rotary electromechanical device includes a first motor including a first stator and a first rotor, a second motor including a second stator and a second rotor, and variable power supplies for driving the respective motors independently of each other, The motors are arranged in series along the axial direction of a rotary shaft. Magnetic poles of the same polarity of the rotors are located at uniform angular positions around the rotary shaft while magnetic poles of the stator of the motor and magnetic poles of the stator of the second motor are displaced from each other in the circumferential direction of the rotary shaft.
    Type: Grant
    Filed: September 14, 2001
    Date of Patent: May 18, 2004
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Akihiro Daikoku, Naoki Hashiguchi
  • Publication number: 20040070300
    Abstract: A motor having a stator and a rotor and wherein the stator has a plurality of stator poles is disclosed. Each of the plurality of stator poles is separated by a stator pole pitch. The rotor is concentrically disposed within the stator and at least one pair of magnets is mounted to the rotor. The at least one pair of magnets has at least one skewed side. Further, the rotor has a uniform variable air gap between an adjacent magnet. The magnet has inner and outer arcuate surfaces. The center of a circle describing the outside diameter of the magnet is off-centered from a circle describing an inside diameter of the magnet. Further, the at least one pair of magnets is skewed by at least one half of stator slot pitch.
    Type: Application
    Filed: October 10, 2002
    Publication date: April 15, 2004
    Inventor: Zhenxing (Zack) Fu
  • Patent number: 6717323
    Abstract: A rotary electric motor has a stator with a plurality of separate and ferromagnetically isolated electromagnet core segments disposed coaxially about an axis of rotation. Core materials such as a soft magnetically permeable medium that is amenable to formation of a variety of particularized shapes. The core segments are supported by a non-ferromagnetic structure. The rotor comprises a plurality of permanent magnets with surfaces that face an air gap separation from the stator, the surfaces having a common geometric configuration. The stator pole surface geometric configuration and the rotor magnet surface geometric configuration are skewed with respect to each other. The effect of this skewing arrangement is to dampen the rate of change of the magnitude of the cogging torque that is produced by the interaction between a rotor magnet and a pole of a non-energized stator electromagnet as the permanent magnet traverses its rotational path.
    Type: Grant
    Filed: June 4, 2002
    Date of Patent: April 6, 2004
    Assignee: Wavecrest Laboratories, LLC
    Inventors: Zareh Soghomonian, Boris A. Maslov, Mark A. Benson
  • Patent number: 6713922
    Abstract: A permanent magnet design includes a magnetic field that is skewed relative to a center line of the magnet body. One surface of the magnet is adapted to be mounted or supported on a motor assembly component such as the rotor. The other side of the magnet body includes at least one surface that is not aligned with the center line of the magnet body. When the magnet is supported on a motor component so that the magnet center line is aligned with the axis of rotation of the motor rotor, the magnetic field of the magnet is not aligned with the rotor axis.
    Type: Grant
    Filed: December 29, 2000
    Date of Patent: March 30, 2004
    Assignee: Otis Elevator Company
    Inventors: Zbigniew Piech, Paul Dieter Wagner
  • Patent number: 6707209
    Abstract: A permanent magnet electric machine with reduced cogging torque includes a plurality of axial rotor sections that are defined on a radially outer surface of a rotor. The axial rotor sections include a set of permanent magnets that are in an unmagnetized state and that have opposite edges that are aligned with an axis of the rotor. The axial rotor sections are rotationally offset such that the edges of the permanent magnets create stair step interfaces. The n sets of permanent magnets are magnetized using a magnetizing fixture. The permanent magnets have a generally rectangular shape and are preferably arc magnets or breadloaf magnets. The conductors of the magnetizing fixture are aligned with the stair step interfaces. A magnetic field induced in the permanent magnets is substantially reduced along the stair step interfaces.
    Type: Grant
    Filed: May 9, 2001
    Date of Patent: March 16, 2004
    Assignee: Emerson Electric Co.
    Inventors: Alan D. Crapo, Todd A. Walls, Richard E. Hartsfield, Jr., Charles P. Ketterer, Ken De Luca
  • Publication number: 20030230947
    Abstract: A fault tolerant electric motor for steering actuation is disclosed. In an exemplary embodiment, the motor includes a stator assembly having a first group of stator windings and a second group of stator windings, thereby forming a redundant pair of stator windings. The first and second groups of stator windings are located within opposite hemispheres of the stator assembly. A rotor assembly is rotatingly disposed within the stator assembly, and has a plurality of magnets disposed around the periphery of a rotor core. Each of the plurality of magnets is arranged into a pair of segments, one of which is shifted from the other with respect to an axis of rotation of the rotor assembly.
    Type: Application
    Filed: June 14, 2002
    Publication date: December 18, 2003
    Inventors: Mohammad S. Islam, Tomy Sebastian
  • Patent number: 6657349
    Abstract: An AC servo motor in which annular polar anisotropic magnets, formed by splitting an anisotropic magnet into two or more portions in an axial line direction, are used in a rotor. The magnetic poles of the split annular polar anisotropic magnets are disposed so as to be shifted by a predetermined angle &thgr;′ which is greater than a skew angle &thgr; determined based on the number of torque ripples per rotation of the rotor determined by the number of magnetic poles and the number of slots in a stator-side iron core. The predetermined angle &thgr;′ is the angle obtained after adding to the skew angle &thgr; a value which takes into consideration magnetic interference between the magnets. The invention provides an AC servomotor which can be controlled with high precision as a result of reducing cogging torque generated between the magnet and the stator-side iron core.
    Type: Grant
    Filed: April 26, 2001
    Date of Patent: December 2, 2003
    Assignee: Sony Corporation
    Inventor: Tetsuharu Fukushima
  • Publication number: 20030011272
    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: Application
    Filed: July 11, 2002
    Publication date: January 16, 2003
    Applicant: Matsushita Electric Industrial Co., Ltd.
    Inventors: Hisakazu Kataoka, Hiroshi Murakami, Hideharu Hiwaki, Sunao Hashimoto, Yasuharu Odachi, Hirohito Hayashi
  • Publication number: 20020163270
    Abstract: A permanent magnet electric motor for use in an elevator installation includes a stator and a rotor assembly. The rotor assembly has a frame on which are mounted at least two rings with permanent magnets. The rings are removably mounted and are laterally fixed together by a fastener that also radially aligns the rings. The number of similar rings used defines a rotor length in multiple values of the ring length. The rings can be shifted by a suitable magnetic angle to permit the generation of a skewing effect of the magnets which reduces or eliminates a cogging torque of the motor. The rotor assembly can be easily and quickly installed and/or removed in very small spaces, especially in elevator installations.
    Type: Application
    Filed: May 2, 2002
    Publication date: November 7, 2002
    Inventor: Enrique Almada
  • Patent number: 6462452
    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 of 72° is provided relatively between the rotor and the stator.
    Type: Grant
    Filed: April 5, 2001
    Date of Patent: October 8, 2002
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Masatsugu Nakano, Tsutomu Tominaga, Hideki Megata
  • Publication number: 20020140308
    Abstract: A brushless DC motor including a stator having plural slots; and a rotor which has plural permanent magnets and is divided into three rotor blocks in a rotation axis direction, the three rotor blocks being layered so that the arrangement angles of the rotor blocks differ from each other by an amount of a mechanical angle in a rotary direction that is equivalent to one third of a pulsation period of cogging torque generated by the rotor and stator. A brushless DC motor including a rotor having plural magnetic poles provided at an equal pitch in a circumferential direction by mounting permanent magnets in magnet mounting holes; and a stator having plural slots arranged at an equal pitch in a circumferential direction.
    Type: Application
    Filed: February 6, 2002
    Publication date: October 3, 2002
    Applicant: KOYO SEIKO CO. LTD.
    Inventors: Hirohide Inayama, Hideki Jonokuchi, Sadaaki Mori, Atsushi Ishihara, Tomofumi Takahashi, Minoru Kitabayashi, Tetsuo Horie
  • Patent number: 6448680
    Abstract: The invention concerns a rotating electric machine which includes a stator equipped with armature coils and a rotor mounted rotating inside the stator. The rotor having a series of magnets with alternating polarities juxtaposed with magnetic parts having magnetic resistance, respectively associated with the magnets. Each assembly of one magnet and one associated magnetic part defining a rotor pole wherein some of the poles have alternately, along a generally tangential direction, a magnet followed by its magnetic part and a magnet preceded by its magnetic part. The invention is applicable to motor vehicle alternators and AC starters.
    Type: Grant
    Filed: October 11, 2000
    Date of Patent: September 10, 2002
    Assignee: Valeo Equipements Electriques Moteur
    Inventor: Antoine Dokou Akemakou
  • Publication number: 20020117933
    Abstract: A rotational electric machine in which a rotor having different-polarity field magnets arranged alternately in a rotational direction is divided axially into two rotor portions so that the axial position of one of the two rotor portions is changed relative to that of the other in accordance with a direction of torque of the rotor or the phase of synthesized magnetic poles of the field magnets is changed relative to that of magnetic poles of the other rotor portion in accordance with a direction of torque of the rotor, and a vehicle loaded with the rotational electric machine.
    Type: Application
    Filed: August 30, 2001
    Publication date: August 29, 2002
    Inventors: Kim Houng Joong, Satoru Okabe
  • Publication number: 20020084711
    Abstract: A permanent magnet design includes a magnetic field that is skewed relative to a center line of the magnet body. One surface of the magnet is adapted to be mounted or supported on a motor assembly component such as the rotor. The other side of the magnet body includes at least one surface that is not aligned with the center line of the magnet body. When the magnet is supported on a motor component so that the magnet center line is aligned with the axis of rotation of the motor rotor, the magnetic field of the magnet is not aligned with the rotor axis.
    Type: Application
    Filed: December 29, 2000
    Publication date: July 4, 2002
    Applicant: Otis Elevator Company
    Inventors: Zbigniew Piech, Paul Dieter Wagner
  • Publication number: 20020067092
    Abstract: A permanent magnet electric machine with reduced cogging torque includes a plurality of axial rotor sections that are defined on a radially outer surface of a rotor. The axial rotor sections include a set of permanent magnets that are in an unmagnetized state and that have opposite edges that are aligned with an axis of the rotor. The axial rotor sections are rotationally offset such that the edges of the permanent magnets create stair step interfaces. The n sets of permanent magnets are magnetized using a magnetizing fixture. The permanent magnets have a generally rectangular shape and are preferably arc magnets or breadloaf magnets. The conductors of the magnetizing fixture are aligned with the stair step interfaces. A magnetic field induced in the permanent magnets is substantially reduced along the stair step interfaces.
    Type: Application
    Filed: May 9, 2001
    Publication date: June 6, 2002
    Inventors: Alan D. Crapo, Todd A. Walls, Richard E. Hartsfield, Charles P. Ketterer, Ken De Luca
  • Patent number: 6388353
    Abstract: A permanent magnet synchronous motor system. The system uses a permanent magnet AC synchronous motor having an elongated housing, of the type used in progressive cavity pumping applications. Within the stator, a multi-section rotor is rotatably mounted. The rotor includes a plurality of rotor sections that are angularly offset from each other. The rotor sections are mounted on a drive shaft, and the sum of the offsets is generally comparable to the angular displacement undergone by the drive shaft under a normal operating load.
    Type: Grant
    Filed: March 30, 2000
    Date of Patent: May 14, 2002
    Assignee: Camco International, Inc.
    Inventors: Joseph C. Liu, Richard Savoie, Dale Smith
  • Patent number: 6384503
    Abstract: A motor has an armature disposed on one of a rotor and a stator and a permanent magnet disposed on the other of the rotor and the stator. The permanent magnet has skewed magnetic poles being magnetized so that a boundary between each pair of skewed magnetic poles is generally S-shaped and opposed areas of pole surfaces of the permanent magnet and the armature gradually increase when the pole surface of the permanent magnet enters a magnetic field region of the pole surface of the armature or gradually decrease when the pole surface of the permanent magnet leaves a magnetic field region of the pole surface of the armature.
    Type: Grant
    Filed: April 18, 2000
    Date of Patent: May 7, 2002
    Assignee: Seiko Instruments Inc.
    Inventors: Tadao Iwaki, Naoki Kawawada, Atsushi Ohta, Koji Nitadori
  • Publication number: 20020047431
    Abstract: An AC servo motor in which annular polar anisotropic magnets, formed by splitting an anisotropic magnet into two or more portions in an axial line direction, are used in a rotor. The magnetic poles of the split annular polar anisotropic magnets are disposed so as to be shifted by a predetermined angle &thgr;′ which is greater than a skew angle &thgr; determined based on the number of torque ripples per rotation of the rotor determined by the number of magnetic poles and the number of slots in a stator-side iron core. The predetermined angle &thgr;′ is the angle obtained after adding to the skew angle &thgr; a value which takes into consideration magnetic interference between the magnets. The invention provides an AC servomotor which can be controlled with high precision as a result of reducing cogging torque generated between the magnet and the stator-side iron core.
    Type: Application
    Filed: April 26, 2001
    Publication date: April 25, 2002
    Inventor: Tetsuharu Fukushima
  • Publication number: 20020003382
    Abstract: A permanent magnet motor having a rotor 9 with a plurality of permanent magnets 8 disposed on the outer circumferential face at a predetermined interval in a peripheral direction, and a stator 6 with a plurality of magnetic pole pieces 3 arranged at a predetermined spacing in the peripheral direction, the magnetic pole pieces 3 being opposed to the permanent magnets 8, the stator 6 surrounding the rotor 9, wherein the auxiliary grooves 4 are provided on a face of each magnetic pole piece 3 of the stator 6 opposed to the permanent magnets 8 of the rotor 9, and a skew having an electric angle of 72° is provided relatively between the rotor 9 and the stator 6.
    Type: Application
    Filed: April 5, 2001
    Publication date: January 10, 2002
    Inventors: Masatsugu Nakano, Tsutomu Tominaga, Hideki Megata