Axial flux machine and low-profile cooling apparatus
An axial flux machine may include a rotor, a first stator, and a second stator. The rotor may generate first magnetic flux within an active region and may have a first generally annular surface oriented normal to its axis of rotation. The first stator may generate second magnetic flux within the active region so that interaction of the second magnetic flux and the first magnetic flux causes the rotor to rotate. The second stator may include at least a first electronic component to be cooled and may have a second generally annular surface positioned in close proximity to and generally parallel to the first generally annular surface so that rotation of the first generally annular surface relative to the second generally annular surface induces flow of a cooling fluid for the first electronic component within a gap between the first generally annular surface and the second generally annular surface.
1 . An axial flux machine, comprising:
a rotor configured to generate first magnetic flux within an active region of the axial flux machine, the rotor being configured to rotate about an axis of rotation and having a first generally annular surface oriented normal to the axis of rotation, the rotor having an outer periphery at a first radial distance from the axis of rotation;
a first stator positioned on a first axial side of the rotor, the first stator being configured to generate second magnetic flux within the active region so that interaction of the second magnetic flux and the first magnetic flux causes the rotor to rotate about the axis of rotation; and
a second stator positioned on a second axial side of the rotor opposite the first axial side, the second stator including at least a first electronic chip to be cooled via a cooling fluid, at least a portion of the first electronic chip being positioned in a region of the second stator that is located within the first radial distance from the axis of rotation, the second stator having a second generally annular surface positioned in close proximity to and generally parallel to the first generally annular surface so that rotation of the first generally annular surface relative to the second generally annular surface induces flow of the cooling fluid for the first electronic chip within a gap between the first generally annular surface and the second generally annular surface so that heat from the first electronic chip is transferred to the cooling fluid.
2 . The axial flux machine of claim 1 , wherein a ratio of (A) a maximum axial distance between an uppermost portion of the first generally annular surface and a lowermost portion of the second generally annular surface to (B) a radial distance between the axis of rotation and an outer diameter of the rotor is less than or equal to 0.05.
3 . The axial flux machine of claim 1 , wherein a maximum axial distance between an uppermost portion of the first generally annular surface and a lowermost portion of the second generally annular surface is less than or equal to 2.0 millimeters.
4 . The axial flux machine of claim 1 , wherein a ratio of (A) a maximum axial distance between an uppermost portion of the first stator and a lowermost portion of the second stator to (B) a radial distance between the axis of rotation and an outer diameter of the rotor is less than or equal to 0.25.
5 . The axial flux machine of claim 1 , wherein a maximum axial distance between an uppermost portion of the first stator and a lowermost portion of the second stator is less than 10 millimeters.
6 . The axial flux machine of claim 1 , wherein the rotor includes a plurality of magnets disposed on the first axial side, the plurality of magnets being configured and arranged to generate the first magnetic flux.
7 . The axial flux machine of claim 6 , wherein the plurality of magnets are arranged to form a Halbach array.
8 . The axial flux machine of claim 1 , wherein the first stator comprises a printed circuit board stator including windings configured and arranged to generate the second magnetic flux when energized with current.
9 . The axial flux machine of claim 1 , wherein the first generally annular surface includes first features that extend into the gap and are configured to modify fluid flow characteristics in the gap between the first generally annular surface and the second generally annular surface.
10 . The axial flux machine of claim 9 , wherein an axial extent of the first features is at most 0.2 their radial extent.
11 . The axial flux machine of claim 1 , wherein the second generally annular surface includes second features that extend into the gap and are configured to modify fluid flow characteristics in the gap between the first generally annular surface and the second generally annular surface.
12 . The axial flux machine of claim 1 , wherein:
the second stator includes a thermally conductive component that overlays at least a portion of the first electronic chip; and
the thermally conductive component includes the second generally annular surface.
13 . The axial flux machine of claim 12 , wherein a ratio of (A) a maximum axial distance between an uppermost portion of the first stator and a lowermost portion of the thermally conductive component to (B) a radial distance between the axis of rotation and an outer diameter of the rotor is less than or equal to 0.25.
14 . The axial flux machine of claim 1 , wherein the second stator is supported by a printed circuit board.
15 . The axial flux machine of claim 1 , wherein the first stator includes a through hole to accommodate flow of the cooling fluid into the gap.
16 . The axial flux machine of claim 1 , wherein the rotor includes a through hole to accommodate flow of the cooling fluid into the gap.
17 . The axial flux machine of claim 1 , further comprising a first axial support extending from the first stator, wherein the first axial support is configured and arranged to support the rotor with respect to the first stator so that the rotor is rotatable relative to the first stator.
18 . The axial flux machine of claim 17 , further comprising a second axial support extending from the first stator, wherein the second axial support is configured and arranged to support the first stator relative to the second stator.
19 . The axial flux machine of claim 18 , wherein the second axial support includes at least one feature configured to engage a hole in the second stator when the at least one feature is inserted into the hole.
20 . The axial flux machine of claim 19 , in combination with a pick-and-place apparatus configured to engage the first stator, move the first stator toward the second stator, and attach the first stator to the second stator by causing the at least one feature to be inserted into the hole.
21 . A method for assembling an axial flux machine, comprising:
moving an assembly including a rotor and a first stator toward a second stator including at least a first electronic chip to be cooled so as to cause the assembly to engage the second stator such that the first stator is positioned on a first axial side of the rotor and the second stator is positioned on a second axial side of the rotor, wherein:
the rotor is configured to generate first magnetic flux within an active region of the axial flux machine;
the first stator is configured to generate second magnetic flux within the active region so that interaction of the second magnetic flux and the first magnetic flux causes the rotor to rotate about an axis of rotation;
the rotor has a first generally annular surface oriented normal to the axis of rotation and an outer periphery at a first radial distance from the axis of rotation; and
the assembly is engaged with the second stator such that:
at least a portion of the first electronic chip is positioned in a region of the second stator that is located within the first radial distance from the axis of rotation, and
a second generally annular surface of the second stator is positioned in close proximity to and generally parallel to the first generally annular surface so that rotation of the first generally annular surface relative to the second generally annular surface induces flow of a cooling fluid for the first electronic chip within a gap between the first generally annular surface and the second generally annular surface so that heat from the first electronic chip is transferred to the cooling fluid.
22 . The axial flux machine of claim 1 , wherein the first electronic chip includes at least one of a graphics processing unit or a central processing unit.
23 . The method of claim 21 , wherein the first stator includes a through hole to accommodate the flow of the cooling fluid into the gap.
24 . The method of claim 21 , wherein:
the assembly includes a first axial support extending from the first stator, the first axial support being configured and arranged to support the rotor with respect to the first stator so that the rotor is rotatable relative to the first stator; and
a second axial support extending from the first stator, the second axial support being configured and arranged to engage the second stator and support the first stator relative to the second stator.
25 . The method of claim 24 , wherein the second axial support includes at least one feature configured to engage a hole in the second stator, and moving the assembly includes:
moving the assembly so that the at least one feature is inserted into the hole.
26 . The method of claim 25 , wherein moving the assembly includes:
using a pick-and-place apparatus to engage the first stator and move the first stator toward the second stator so that the at least one feature is inserted into the hole.
27 . The method of claim 21 , wherein:
the rotor includes a plurality of magnets disposed on the first axial side, the plurality of magnets being configured and arranged to generate the first magnetic flux.
28 . The method of claim 27 , wherein the plurality of magnets are arranged to form a Halbach array.
29 . The method of claim 21 , wherein the first stator comprises a printed circuit board stator including windings configured and arranged to generate the second magnetic flux when energized with current.
30 . The method of claim 21 , wherein the first electronic chip includes at least one of a graphics processing unit or a central processing unit.