Pole shoe cooling gap for axial motor
There is provided an axial flux motor comprising one or more rotating disks ( 10 ) and a stator ( 20 ) comprising a cavity ( 30 ) formed between walls ( 40 a, 40 b ) and containing therein more than one electro-magnetic coil assembly ( 50 ). Each electro-magnetic coil assembly ( 50 ) comprises more than one pole piece ( 60 ), each having an axially extending shank portion ( 70 a ) and first and second radially extending end shoes ( 72 a, 72 b ) and one or more associated coils ( 55 ), each of the one or more associated coils ( 55 ) being wound around a shank portion ( 70 a ), wherein said outer surface ( 75 ) of said end shoes are preferably joined to one or other of said walls ( 40 a, 40 b ). One or both of said first or second shoes further comprise a heat exchange surface ( 72 a 1, 72 b 1 ) facing a coil ( 55 ) wound around the shank ( 70 a ) such as to define first cooling channels ( 100 a, 100 b ) between one or both of said heat exchange surface ( 72 a 1, 72 b 1 ) and said coil ( 55 ), and a second flow channel ( 100 c ) defined by the spacing of said coil ( 55 ) and adjacent coils ( 55 ).
1. An axial flux motor comprising:
one or more rotating disks;
a stator, having a cavity formed between walls and containing therein more than one electro-magnetic coil assemblies comprising more than one pole pieces each having an axially extending shank portion;
first and second radially extending end shoes at ends of said one or more shank portions; and
one or more coils each wound around a shank portion,
wherein:
said end shoes include one or more outer surfaces one or more of which are joined to one or other of said walls;
one or both of said first or second shoes further comprise a heat exchange surface facing the coil such as to define one or more first cooling channels between one or both of said heat exchange surface and said coil; and
the motor further includes:
a second cooling channel defined by the spacing of adjacent coils, the second cooling channel being in fluid communication with the one or more first cooling channels, and
a liquid coolant for flowing within the first and second cooling channels, wherein heat from the coils and heat exchange surfaces of the shoes is transferred to the liquid coolant and away from the coils and heat exchange surfaces.
2. The axial flux motor as claimed in claim 1 , wherein each of said heat exchange surfaces are spaced from said coil such as to define said first cooling channels between each heat exchange surface and said coil.
3. The axial flux motor as claimed in claim 1 , wherein said coils are spaced from one or more of said heat exchange surface by a spacer.
4. The axial flux motor as claimed in claim 1 wherein each of said coils comprises a tapered coil as viewed from a cross section of the stator through a plane that extends in an axial direction through the shoes and the shank portion around which the respective coil is wound, wherein, as viewed through the cross sectional plane, the tapered coil has a base adjacent the shank portion that is wider than a outward surface of the tapered coil that is spaced apart from the base and the shank portion and wherein said base extends along a greater length of said shank portion than said outward surface such as to define a tapered cooling channel with each of the end shoes.
5. The axial flux motor as claimed in claim 3 , wherein said spacer comprises a protrusion on said shank portion that is axially disposed between at least one end shoe and the coil.
6. The axial flux motor as claimed in claim 1 and further including one or more turbulence generators within the one or more cooling channels.
7. The axial flux machine as claimed in claim 6 , wherein said one or more turbulence generators comprise detents on one or more of said one or more heat exchange surfaces.
8. The axial flux machine as claimed in claim 1 and further including a bobbin and wherein said coil is mounted upon and around said bobbin.
9. The axial flux machine as claimed in claim 8 and wherein said bobbin includes one or more spacers to space said coil from one or other or both of the heat exchange surfaces.
10. The axial flux machine as claimed in claim 8 and wherein said bobbin further includes one or more further spacers to space the coil from the bobbin itself and defining one or more inner cooling paths between the bobbin and the end face or faces of the coil.
11. The axial flux motor as claimed in claim 8 and wherein said bobbin is electrically insulating.
12. The axial flux motor as claimed in claim 8 wherein said bobbin includes an interior shaped to fit around the pole piece.
13. The axial flux motor as claimed in claim 1 and further including a liquid coolant supply means for directing the liquid coolant into said one or more cooling channels.