Patents by Inventor Todd A. Walls

Todd A. Walls has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 8350435
    Abstract: An interior permanent magnet machine has non-contiguous, non-magnetic radial slots between the magnets and the cylindrical periphery and the magnets have non-magnetic radial end slots.
    Type: Grant
    Filed: March 5, 2010
    Date of Patent: January 8, 2013
    Assignee: Emerson Electric Co.
    Inventors: Keith I. Hoemann, Todd A. Walls
  • Publication number: 20100156234
    Abstract: An interior permanent magnet machine has non-contiguous, non-magnetic radial slots between the magnets and the cylindrical periphery and the magnets have non-magnetic radial end slots.
    Type: Application
    Filed: March 5, 2010
    Publication date: June 24, 2010
    Applicant: EMERSON ELECTRIC CO.
    Inventors: Keith I. Hoemann, Todd A. Walls
  • Patent number: 7705502
    Abstract: An interior permanent magnet machine having angled slots.
    Type: Grant
    Filed: April 14, 2006
    Date of Patent: April 27, 2010
    Assignee: Emerson Electric Co.
    Inventors: Keith I. Hoemann, Todd A. Walls
  • Patent number: 7245054
    Abstract: A permanent magnet electric machine includes a stator with salient stator poles. A rotor includes two or more axial rotor sections that are rotationally offset by an offset angle equal to the cogging angle divided by the number of axial rotor sections. The axial rotor sections include rotor poles with permanent magnets. In one embodiment, the permanent magnet electric machine has a 12/10 slot/pole combination. The permanent magnets have a magnet dimension angle between 31 and 35 degrees. An air gap ratio of the electric machine is between 1.35 and 2.5. A slot opening ratio of the electric machine is less than or equal to one. In another embodiment, the permanent magnet electric machine has an 18/12 slot/pole combination. The permanent magnets have a magnet dimension angle that is between 25 and 28 degrees. An air gap ratio of the electric machine is between 1.35 and 2.5. A slot opening ratio of the electric machine is less than or equal to one.
    Type: Grant
    Filed: November 1, 2000
    Date of Patent: July 17, 2007
    Assignee: Emerson Electric Co.
    Inventors: Todd A. Walls, Alan D. Crapo
  • Patent number: 7034423
    Abstract: An electric power steering system for a vehicle includes a steering wheel and a steering shaft that is connected to the steering wheel. A worm gear is connected to the steering shaft. A worm is threadably engaged to the worm gear. A permanent magnet motor is connected to the worm. The permanent magnet motor includes a stator with twelve slots and a rotor with ten poles. The rotor includes one or more axial rotor sections. If more than one axial rotor section is employed, the axial rotor sections are rotationally offset. The axial rotor sections are rotationally offset by an offset angle that is equal to a cogging angle divided by the number of axial rotor sections. The rotor includes breadloaf, spoke, radial or arc permanent magnets.
    Type: Grant
    Filed: May 7, 2003
    Date of Patent: April 25, 2006
    Inventors: Alan D. Crapo, Todd A. Walls, Richard E. Hartsfield, Jr.
  • 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: 20030201137
    Abstract: An electric power steering system for a vehicle includes a steering wheel and a steering shaft that is connected to the steering wheel. A worm gear is connected to the steering shaft. A worm is threadably engaged to the worm gear. A permanent magnet motor is connected to the worm. The permanent magnet motor includes a stator with twelve slots and a rotor with ten poles. The rotor includes one or more axial rotor sections. If more than one axial rotor section is employed, the axial rotor sections are rotationally offset. The axial rotor sections are rotationally offset by an offset angle that is equal to a cogging angle divided by the number of axial rotor sections. The rotor includes breadloaf, spoke, radial or arc permanent magnets.
    Type: Application
    Filed: May 7, 2003
    Publication date: October 30, 2003
    Inventors: Alan D. Crapo, Todd A. Walls, Richard E. Hartsfield
  • Patent number: 6597078
    Abstract: An electric power steering system for a vehicle includes a steering wheel and a steering shaft that is connected to the steering wheel. A worm gear is connected to the steering shaft. A worm is threadably engaged to the worm gear. A permanent magnet motor is connected to the worm. The permanent magnet motor includes a stator with twelve slots and a rotor with ten poles. The rotor includes one or more axial rotor sections. If more than one axial rotor section is employed, the axial rotor sections are rotationally offset. The axial rotor sections are rotationally offset by an offset angle that is equal to a cogging angle divided by the number of axial rotor sections. The rotor includes breadloaf, spoke, radial or arc permanent magnets.
    Type: Grant
    Filed: January 30, 2001
    Date of Patent: July 22, 2003
    Assignee: Emerson Electric Co.
    Inventors: Alan D. Crapo, Todd A. Walls, Richard E. Hartsfield, Jr.
  • Publication number: 20020101126
    Abstract: An electric power steering system for a vehicle includes a steering wheel and a steering shaft that is connected to the steering wheel. A worm gear is connected to the steering shaft. A worm is threadably engaged to the worm gear. A permanent magnet motor is connected to the worm. The permanent magnet motor includes a stator with twelve slots and a rotor with ten poles. The rotor includes one or more axial rotor sections. If more than one axial rotor section is employed, the axial rotor sections are rotationally offset. The axial rotor sections are rotationally offset by an offset angle that is equal to a cogging angle divided by the number of axial rotor sections. The rotor includes breadloaf, spoke, radial or arc permanent magnets.
    Type: Application
    Filed: January 30, 2001
    Publication date: August 1, 2002
    Inventors: Alan D. Crapo, Todd A. Walls, Richard E. Hartsfield
  • 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