Cooling of axial flux motors—centrifugal
The present invention provides an axial flux motor ( 10 ) having: a rotor ( 20 ) having a radially extending portion ( 20 r ) and an axially extending portion ( 20 c ) having a first side ( 20 a ) and a second side ( 20 b ); a stator ( 22 ) having an inner aperture ( 30 ), a front wall ( 34 ) having a first side ( 34 s ) and a second side ( 34 i ) and being axially spaced from the first side ( 20 a ) of the rotor ( 20 ) by a gap ( 38 ), a bearing member ( 32 ) within the inner aperture ( 30 ) of the stator ( 22 ) and supporting the axially extending portion ( 20 c ) of the rotor ( 20 ); a casing ( 40 ) having an axially and circumferentially extending outer portion ( 48 ) surrounding said rotor ( 20 ) and having an inner surface ( 43 ); a cover plate ( 42 ) having an inner face ( 42 i ) confronting and being spaced from said second side ( 20 b ) of said rotor ( 20 ); a containment chamber ( 26 ) including said second side ( 34 i ), and said inner face ( 42 i ) of said cover plate ( 42 ) and having a top portion ( 45 ); a sump ( 50 ) within the containment chamber ( 26 ); and one or more first flow diverters ( 60 ) on the inner surface ( 43 ) of casing ( 40 ) to direct liquid towards said first and/or second inner side faces ( 34 i, 42 i ).
1. An axial flux motor comprising:
a rotor having a radially extending portion and an axially extending portion having a first side and a second side;
a stator having an inner aperture, a front wall having a first side and a second side and being axially spaced from the first side of the rotor by a gap;
a bearing member within the inner aperture of the stator and supporting the axially extending portion of the rotor;
a casing having an axially and circumferentially extending outer portion surrounding said rotor and having an inner circumferential surface;
a cover plate having an inner face confronting and being spaced from said second side of said rotor;
a containment chamber including said second side of said stator and said inner face of said cover plate and having an upper portion, said containment chamber being partially filled with a volume of cooling liquid for cooling the rotor;
a sump within the containment chamber for receiving the cooling liquid; and
one or more first flow diverters on the inner circumferential surface of said casing to direct said cooling liquid towards said second side of said stator and/or said inner face of said cover plate,
wherein the volume of cooling fluid is such that, when the rotor rotates, said cooling fluid in the sump is picked up by the rotor and thrown centrifugally outwardly towards said inner circumferential surface of said casing.
2. The axial flux motor as claimed in claim 1 and wherein said one or more first flow diverters comprise axially extending portions extending between said inner surface of said casing and one or other of said second side of said stator and said inner side face of said cover plate.
3. The axial flux motor as claimed in claim 2 and including one or more flow interrupters circumferentially spaced around said inner circumferential surface.
4. The axial flux motor as claimed in claim 3 wherein said flow director comprises a wicking material.
5. The axial flux motor as claimed in claim 1 and including a plurality of flow diverters and wherein said diverters are circumferentially spaced around said inner circumferential surface.
6. The axial flux motor as claimed in claim 1 and including a flow splitter radially outward of said rotor.
7. The axial flux motor as claimed in claim 6 and including one or more flow interrupters circumferentially spaced around said inner circumferential surface.
8. The axial flux motor as claimed in claim 1 and including a flow director on one or other or both of said second side of said stator and said inner face of said cover plate.
9. The axial flux motor as claimed in claim 8 and wherein said flow director comprises a plurality of grooves within the surface of one or other or both of said second side of said stator and said inner face of said cover plate.
10. The axial flux motor as claimed in claim 8 wherein said flow director extends radially inwardly towards said bearing member.
11. The axial flux motor as claimed in claim 1 and including a second flow diverter extending axially from said cover plate inner face and towards said bearing member.
12. The axial flux motor as claimed in claim 11 and wherein said rotor includes a hollow shaft portion and wherein said second flow diverter extends into said hollow shaft portion and terminates proximal to said bearing member.
13. The axial flux motor as claimed in claim 12 and wherein the axially extending portion of rotor includes an inner surface and an outer surface and further includes one or more secondary flow directors comprising radially extending passageways extending therebetween.
14. The axial flux motor as claimed in claim 1 , wherein said bearing lies between said sump and said top portion of the containment chamber.