Raxial flow fan for cooling of axial flux machine and drive
A centrifugal fan, positioned in a gap between a first surface and a second surface, includes blades extending in a radial direction and a baffle attached to the blades, the baffle being configured and arranged (i) to cause cooling fluid to be drawn into one or more first openings on a first axial side of the centrifugal fan that faces the first surface, thereby generating a first flow of cooling fluid in an inward radial direction over the first surface, and (ii) to redirect the fluid flow at least partially in an axial direction toward the second surface so that the cooling fluid is expelled from one or more second openings on a second axial side of the centrifugal fan that faces the second surface, thereby causing a second flow of cooling fluid in an outward radial direction over the second surface.
1 . An apparatus, comprising:
a first housing supporting an axial flux machine including a stator and a rotor configured to rotate about an axis of rotation, wherein the stator includes conductive windings, and the rotor includes a shaft and one or more magnets to generate magnetic flux that links with the conductive windings;
a second housing supporting power electronic components to control current flow through the conductive windings, the second housing being axially spaced from the first housing to form a gap between a first surface and a second surface that faces the first surface, wherein (i) (i) the first surface is on the first housing and faces away from the stator and the rotor, and the second surface is on the second housing and faces away from the power electronic components, or (ii) the first surface is on the second housing and faces away from the power electronic components, and the second surface is on the first housing and faces away from the stator and the rotor; and
a centrifugal fan positioned in the gap and coupled to the shaft so that the centrifugal fan rotates about the axis of rotation, the centrifugal fan including:
blades extending in a radial direction to generate fluid flow in the radial direction, and
a baffle integrated with the blades so that the blades and the baffle rotate as a unit about the axis of rotation, the baffle being configured and arranged (i) to cause cooling fluid to be drawn into one or more first openings on a first axial side of the centrifugal fan that faces the first surface, thereby generating a first flow of cooling fluid in an inward radial direction over the first surface, and (ii) to redirect the fluid flow at least partially in an axial direction toward the second surface so that the cooling fluid is expelled from one or more second openings on a second axial side of the centrifugal fan that faces the second surface, thereby causing a second flow of cooling fluid in an outward radial direction over the second surface, wherein the baffle includes an outer portion that is positioned on a first axial side of the centrifugal fan and at least partially covers gaps between the blades adjacent an outer periphery of the centrifugal fan, the outer portion being configured and arranged to redirect the fluid flow at least partially in the axial direction toward the second surface.
2 . The apparatus of claim 1 , wherein the first surface is on the first housing and the second surface is on the second housing.
3 . The apparatus of claim 1 , wherein the first surface is on the second housing and the second surface is on the first housing.
4 . The apparatus of claim 1 , wherein the blades are straight.
5 . The apparatus of claim 4 , wherein the blades are oriented in respective planes parallel to the axis of rotation.
6 . The apparatus of claim 5 , wherein the respective planes are coincident with the axis of rotation.
7 . The apparatus of claim 1 , wherein the outer portion extends in a raxial direction so as to redirect the fluid flow in the raxial direction.
8 . The apparatus of claim 1 , wherein the one or more first openings are positioned adjacent an inner periphery of the centrifugal fan.
9 . The apparatus of claim 8 , wherein the baffle further includes a first generally annular section positioned on the first axial side radially inward of the outer portion such that a radial width of the first generally annular section defines a size of the one or more first openings.
10 . The apparatus of claim 9 , wherein the baffle further includes a second generally annular portion positioned radially outward of the outer portion.
11 . The apparatus of claim 10 , wherein the second generally annular portion is positioned on a second axial side of the centrifugal fan opposite the first axial side.
12 . The apparatus of claim 1 , wherein the centrifugal fan includes an inner portion that is tapered in a same direction as the outer portion about the axis of rotation so as to form channels for fluid flow.
13 . The apparatus of claim 1 , wherein the first surface includes first fins defining first fluid flow channels for the first flow of cooling fluid in the inward radial direction and the second surface includes second fins defining second fluid flow channels for the second flow of cooling fluid in the outward radial direction.
14 . A method for using the apparatus of claim 1 , comprising:
operating the power electronic components to control current flow through the conductive windings to cause rotation of rotor and shaft and thereby cause rotation of the blades of the centrifugal fan to generate the fluid flow in the radial direction.