Direct drive electric motor having stator and magnet configurations for improved torque capability

Abstract

An electric motor for an appliance includes a rotor coupled with a drive shaft. The rotor includes a plurality of rotor magnets that each define a magnet assembly including a plurality of magnet portions having different magnet pole orientations. A stator is in electromagnetic communication with the rotor. A gap is defined between the stator and the rotor. The stator comprises a stator core. A plurality of stator poles define the gap. Stator magnets are positioned within the stator core and are located to partially define the gap. Each stator magnet defines a pair of flux paths that extend around an outer perimeter of the stator magnet and onto the gap. The different magnet pole orientations of the plurality of rotor magnets operate to direct an effective magnetic flux toward the gap.

What is claimed is: 
     
         1 . A stator comprising:
 a stator core;   a plurality of inner stator teeth that extend from the stator core, wherein each tooth of the plurality of inner stator teeth includes angled portions; and   stator magnets that are positioned within a gap-facing surface of each respective tooth of the plurality of inner stator teeth, respectively, wherein each stator magnet of the stator magnets includes chamfered portions that cooperate with the angled portions of each respective tooth to define a pair of flux paths having a consistent shape and thickness that decreases a density of magnetic flux around the stator magnets, and wherein each of the pair of flux paths extend around an outer perimeter of the respective stator magnet and through the gap-facing surface of the respective tooth.   
     
     
         2 . The stator of  claim 1 , wherein the stator magnets are positioned at least within the gap-facing surface of the plurality of inner stator teeth. 
     
     
         3 . The stator of  claim 1 , wherein the chamfered portions of each of the stator magnets includes a pair of chamfered portions that define the pair of flux paths. 
     
     
         4 . The stator of  claim 3 , wherein the pair of chamfered portions defines the consistent shape of the respective stator tooth at the stator magnet. 
     
     
         5 . The stator of  claim 1 , wherein each of the stator magnets includes a curved surface that matches a curvature of the gap-facing surface of the plurality of inner stator teeth. 
     
     
         6 . The stator of  claim 5 , wherein each of the stator magnets are positioned to direct a magnetic north pole away from the gap-facing surface. 
     
     
         7 . The stator of  claim 1 , wherein a portion of each of the stator magnets are positioned within magnet recesses that are defined within the plurality of inner stator teeth, respectively, wherein each of the magnet recesses are positioned at the gap-facing surface. 
     
     
         8 . The stator of  claim 1 , wherein the stator core is integral with the plurality of inner stator teeth, wherein the plurality of inner stator teeth define inner stator poles. 
     
     
         9 . The stator of  claim 8 , wherein each of the stator magnets are positioned within the plurality of inner stator teeth and each respective tooth of the plurality of inner stator teeth includes a single magnet recess that divides the inner stator poles into pairs of the effective inner stator poles. 
     
     
         10 . An electric motor comprising:
 a rotor coupled with a drive shaft; and   a stator in electromagnetic communication with the rotor, wherein a gap is defined between the stator and the rotor, the stator having a plurality of stator poles, each stator pole of the plurality of stator poles comprising:
 a stator tooth that defines the gap, the stator tooth having opposing angled portions; and 
 a stator magnet located at a gap-facing surface of the stator tooth to further define the gap, wherein the stator magnet includes a pair of chamfered portions that cooperate with the opposing angled portions to define a pair of flux paths that extend around an outer perimeter of the stator magnet and into the gap, the pair of flux paths having a consistent shape of the stator tooth at the stator magnet that decreases a density of magnetic flux around the stator magnet. 
   
     
     
         11 . The electric motor of  claim 10 , wherein the rotor includes a plurality of rotor magnets that each define a magnet assembly including a plurality of magnet portions having different magnet pole orientations. 
     
     
         12 . The electric motor of  claim 11 , wherein the different magnet pole orientations of the plurality of rotor magnets operate to direct an effective magnetic flux toward the gap. 
     
     
         13 . The electric motor of  claim 11 , wherein the plurality of magnet portions includes a center magnet and two flanking magnets that each direct a respective magnetic north pole toward the center magnet that directs the respective magnetic north pole toward the gap. 
     
     
         14 . The electric motor of  claim 10 , wherein the rotor is an inner rotor and the stator includes a plurality of inward extending teeth that define the plurality of stator poles. 
     
     
         15 . The electric motor of  claim 10 , wherein each stator pole of the plurality of stator poles further comprises a curved surface that defines the gap, and wherein the stator magnet is positioned to direct a magnetic north pole away from the curved surface. 
     
     
         16 . The electric motor of  claim 15 , wherein each stator pole of the plurality of stator poles further comprises a magnet recess that receives the stator magnet, wherein each magnet recess is positioned at the gap-facing surface of the stator tooth. 
     
     
         17 . The electric motor of  claim 10 , wherein each stator pole of the plurality of stator poles further comprises a magnet recess defined within the stator tooth, wherein the stator magnet is positioned within the magnet recess that divides the stator tooth to define pairs of the effective inner stator poles that are defined by the consistent shape of the stator tooth at the stator magnet. 
     
     
         18 . A stator comprising:
 a stator core;   a plurality of stator poles that extend inward toward a rotor to define a gap; and   stator magnets that are positioned within the stator core at a gap-facing surface of the plurality of stator poles, respectively, to at least partially define the gap, wherein   the stator core and the stator magnets cooperate to define a curvature of the gap-facing surface that is concentric with a rotational axis of the rotor, and wherein the stator core and the stator magnets further cooperate to define matching chamfered portions of each stator pole of the plurality of stator poles, the matching chamfered portions corresponding to a pair of flux paths that decrease a density of magnetic flux around the stator magnets.   
     
     
         19 . The stator of  claim 18 , wherein the pair of flux paths include a consistent shape and thickness within each respective stator pole of the plurality of stator poles. 
     
     
         20 . The stator of  claim 18 , wherein the rotor includes a plurality of rotor magnets that each define a magnet assembly including a plurality of magnet portions having different magnet pole orientations, wherein the different magnet pole orientations of the plurality of rotor magnets operate to direct an effective magnetic flux toward the gap.