US 2006/0131986 A1 · Axial gap permanent magnet reluctance motor and method

Abstract

An electric machine (10) has a disk-shaped rotor (24) disposed in an operating space between two opposing stator assemblies (11, 12) to provide two axial air gaps (15, 16). The rotor (24) has a hub (28) and an outer ring (26) of non-magnetic material and is further provided with a plurality of permanent magnetic elements (25) for coupling flux that is induced by the magnetic field of the stator assemblies (11, 12). The permanent magnetic elements (25) are spaced apart and reluctance poles (27) are positioned in spaces between the magnetic elements (25) to couple additional flux induced by the magnetic field of the stator assemblies (11, 12). Various constructions and shapes (40-45) for the PM magnetic elements (25) are disclosed, and including PM covers (60) of ferromagnetic material for enhancing q-axis flux in the air gaps (15, 16) and for reducing harmonics where toothed stators are used. Methods of providing increased torque using the the various rotor constructions are also disclosed.

Claims22

Dependent claims

A brushless electric machine, comprising:

at least one stator assembly for receiving ac electrical power to provide a magnetic field;
a rotor disposed within the magnetic field of the stator assembly and spaced from the stator to define a primary air gap relative to an axis of rotation for the rotor;
wherein the rotor is disk-shaped and is spaced from the stator assembly along an axis of rotation for the rotor to form a first axial air gap;
further comprising a second stator assembly disposed on an opposite side of the rotor from the at least one stator assembly and separated from the rotor by a second axial air gap;
and
wherein the disk-shaped rotor further comprises a non-magnetic hub and a non-magnetic outer ring;
wherein the rotor is provided with a plurality of permanent magnetic elements for coupling flux that is induced by the magnetic field of the stator assembly;
and
wherein the permanent magnetic elements are spaced apart and wherein reluctance poles of ferromagnetic material are positioned in spaces between the magnetic elements to couple additional flux induced by the magnetic field of the stator assembly, whereby a flux return path through ferromagnetic material is limited in the rotor to the reluctance poles.

6 more elements

Dependencies are inferred from the claim text.

Axial gap permanent magnet reluctance motor and method

Life of this patent

Axial gap permanent magnet reluctance motor and method

Life of this patent

Abstract

Claims22