Emerson Electric Company

Other

Todd A Walls

Alan D Crapo

Richard E Hartsfield, Jr

Keith I Hoemann

Charles P Ketterer

Jeffrey P Mahn

Jeffrey D Neumann

Ken De Luca

Bradley Gerard Kohring

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.

Interior magnet machine with reduced cogging

An interior permanent magnet machine having angled slots.

Interior magnet machine with non-perpendicular slots

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.

Permanent magnet electric machine having reduced cogging torque

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.

Electric power steering system including a permanent magnet motor

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.

Reduced cogging torque permanent magnet electric machine with rotor having offset sections

An electromagnetic device of significantly reduced size is provided by the specific designs of the end shields of the device and by the specific designs of insulating end caps of the device that insulate the electrical component parts of the device from contact and possible shorting with mechanical structural parts of the device.

Growing community of inventors

Rock Hill, MO, United States of America

Todd A Walls