Selectively pocketed back iron for axial flux machines
A rotor component for a motor or generator may include a support structure made of a magnetic material, a first magnet, and a second magnet. The first magnet may be attached to a first portion of the support structure to form a first magnetic pole of the motor or generator, and the second magnet may be attached to a second portion of the support structure to form a second magnetic pole of the motor or generator. The magnetic material of the support structure may provide a flux return path from the first magnet to the second magnet via the first portion and the second portion, and the first portion of the support structure may include a first plurality of pocket features that are free of the magnetic material.
1 . A rotor component for a motor or generator, comprising:
a support structure made of a magnetic material;
a first magnet attached to a first portion of the support structure to form a first magnetic pole of the motor or generator; and
a second magnet attached to a second portion of the support structure to form a second magnetic pole of the motor or generator;
wherein:
the magnetic material of the support structure provides a flux return path from the first magnet to the second magnet via the first portion and the second portion,
the first portion of the support structure includes a first plurality of pocket features that are free of the magnetic material,
the first plurality of pocket features includes at least a first pocket feature, a second pocket feature adjacent the first pocket feature, a third pocket feature, and a fourth pocket feature adjacent the third pocket feature, and
a first distance between the first pocket feature and the second pocket feature is greater than a second distance between the third pocket feature and the fourth pocket feature.
2 . The rotor component of claim 1 , wherein:
the support structure includes a third portion positioned between the first portion and the second portion so that the flux return path from the first magnet to the second magnet passes through the third portion; and
the third portion is generally free of the pocket features.
3 . The rotor component of claim 2 , wherein:
the second portion of the support structure includes a second plurality of pocket features that are free of the magnetic material.
4 . The rotor component of claim 1 , wherein:
the third pocket feature and the fourth pocket feature have a greater depth than the first pocket feature and the second pocket feature.
5 . The rotor component of claim 4 , wherein the third pocket feature and the fourth pocket feature are located closer to a center of the first magnetic pole than the first pocket feature and the second pocket feature.
6 . The rotor component of claim 1 , wherein the third pocket feature and the fourth pocket feature are located closer to a center of the first magnetic pole than the first pocket feature and the second pocket feature.
7 . The rotor component of claim 1 , wherein individual pocket features of the first plurality of pocket features have closed perimeters at a surface of the first portion.
8 . The rotor component of claim 1 , wherein the first pocket feature, the second pocket feature, the third pocket feature, and the fourth pocket feature are generally hexagonally shaped.
9 . A rotor component for a motor or generator, comprising:
a support structure made of a magnetic material;
a first magnet attached to a first portion of the support structure to form a first magnetic pole of the motor or generator; and
a second magnet attached to a second portion of the support structure to form a second magnetic pole of the motor or generator;
wherein:
the magnetic material of the support structure provides a flux return path from the first magnet to the second magnet via the first portion and the second portion,
the first portion of the support structure includes a first plurality of pocket features that are free of the magnetic material,
the first plurality of pocket features includes at least a first pocket feature having a first closed perimeter at a surface of the first portion and a second pocket feature having a second closed perimeter at the surface of the first portion, and
the first closed perimeter is greater than the second closed perimeter.
10 . The rotor component of claim 9 , wherein the first pocket feature is located closer to a center of the first magnetic pole than the second pocket feature.
11 . The rotor component of claim 9 , wherein:
the first pocket feature has a first volume and the second pocket feature has a second volume; and
the first volume is greater than the second volume.
12 . The rotor component of claim 11 , wherein the first pocket feature is located closer to a center of the first magnetic pole than the second pocket feature.
13 . The rotor component of claim 9 , wherein the first pocket feature and the second pocket feature are generally hexagonally shaped.
14 . A rotor component configured for use in an axial flux motor or generator, comprising:
a support structure made of a magnetic material, the support structure forming an annulus;
a first magnet attached to a first portion of the support structure to form a first magnetic pole of the axial flux motor or generator, the first portion being a first angular portion of the annulus; and
a second magnet attached to a second portion of the support structure to form a second magnetic pole of the axial flux motor or generator, the second portion being a second angular portion of the annulus;
wherein:
the magnetic material of the support structure provides a flux return path from the first magnet to the second magnet via the first portion and the second portion,
the first portion of the support structure includes a first plurality of pocket features that are free of the magnetic material,
the first plurality of pocket features includes at least a first pocket feature and a second pocket feature,
the first pocket feature is located at a first angular position within the first angular portion,
the second pocket feature is located at a second angular position, different than the first angular position, within the first angular portion, and
the first pocket feature has a greater depth than the second pocket feature.
15 . The rotor component of claim 14 , wherein the first angular position is closer to a center of the first magnetic pole than the second angular position.
16 . The rotor component of claim 14 , wherein the first pocket feature and the second pocket feature are generally hexagonally shaped.
17 . A rotor component configured for use in an axial flux motor or generator, comprising:
a support structure made of a magnetic material, the support structure forming an annulus;
a first magnet attached to a first portion of the support structure to form a first magnetic pole of the axial flux motor or generator, the first portion being a first angular portion of the annulus; and
a second magnet attached to a second portion of the support structure to form a second magnetic pole of the axial flux motor or generator, the second portion being a second angular portion of the annulus;
wherein:
the magnetic material of the support structure provides a flux return path from the first magnet to the second magnet via the first portion and the second portion,
the first portion of the support structure includes a first plurality of pocket features that are free of the magnetic material,
the first plurality of pocket features includes at least a first pocket feature, a second pocket feature adjacent the first pocket feature, a third pocket feature, and a fourth pocket feature adjacent the third pocket feature,
the first pocket feature and the second pocket feature are located at a first angular position within the first angular portion,
the second pocket feature and the third pocket feature are located at a second angular position, different than the first angular position, within the first angular portion, and
a first distance between the first pocket feature and the second pocket feature is greater than a second distance between the third pocket feature and the fourth pocket feature.
18 . The rotor component of claim 17 , wherein the second angular position is closer to a center of the first magnetic pole than the first angular position.
19 . A rotor component configured for use in an axial flux motor or generator, comprising:
a support structure made of a magnetic material, the support structure forming an annulus;
a first magnet attached to a first portion of the support structure to form a first magnetic pole of the axial flux motor or generator, the first portion being a first angular portion of the annulus; and
a second magnet attached to a second portion of the support structure to form a second magnetic pole of the axial flux motor or generator, the second portion being a second angular portion of the annulus;
wherein:
the magnetic material of the support structure provides a flux return path from the first magnet to the second magnet via the first portion and the second portion,
the first portion of the support structure includes a first plurality of pocket features that are free of the magnetic material,
the first plurality of pocket features includes at least a first pocket feature having a first closed perimeter at a surface of the first portion and a second pocket feature having a second closed perimeter at the surface of the first portion,
the first pocket feature is located at a first angular position within the first angular portion,
the second pocket feature is located at a second angular position, different than the first angular position, within the first angular portion, and
the first closed perimeter is greater than the second closed perimeter.
20 . The rotor component of claim 19 , wherein the first angular position is closer to a center of the first magnetic pole than the second angular position.
21 . A rotor component configured for use in an axial flux motor or generator, comprising:
a support structure made of a magnetic material, the support structure forming an annulus;
a first magnet attached to a first portion of the support structure to form a first magnetic pole of the axial flux motor or generator, the first portion being a first angular portion of the annulus; and
a second magnet attached to a second portion of the support structure to form a second magnetic pole of the axial flux motor or generator, the second portion being a second angular portion of the annulus;
wherein:
the magnetic material of the support structure provides a flux return path from the first magnet to the second magnet via the first portion and the second portion,
the first portion of the support structure includes a first plurality of pocket features that are free of the magnetic material,
the first plurality of pocket features includes at least a first pocket feature having a first volume and a second pocket feature having a second volume,
the first pocket feature is located at a first angular position within the first angular portion,
the second pocket feature is located at a second angular position, different than the first angular position, within the first angular portion, and
the first volume is greater than the second volume.
22 . The rotor component of claim 21 , wherein the first angular position is closer to a center of the first magnetic pole than the second angular position.
23 . A rotor component configured for use in an axial flux motor or generator, comprising:
a support structure made of a magnetic material, the support structure forming an annulus;
a first magnet attached to a first portion of the support structure to form a first magnetic pole of the axial flux motor or generator, the first portion being a first angular portion of the annulus; and
a second magnet attached to a second portion of the support structure to form a second magnetic pole of the axial flux motor or generator, the second portion being a second angular portion of the annulus;
wherein:
the magnetic material of the support structure provides a flux return path from the first magnet to the second magnet via the first portion and the second portion,
the first portion of the support structure includes a first plurality of pocket features that are free of the magnetic material,
the first plurality of pocket features includes at least a first pocket feature and a second pocket feature,
the first pocket feature is located at a first radial distance from a center of the annulus,
the second pocket feature is located at a second radial distance, different than the first radial distance, from the center of the annulus, and
the first pocket feature has a greater depth than the second pocket feature.
24 . The rotor component of claim 23 , wherein the first radial distance is greater than the second radial distance.
25 . A rotor component configured for use in an axial flux motor or generator, comprising:
a support structure made of a magnetic material, the support structure forming an annulus;
a first magnet attached to a first portion of the support structure to form a first magnetic pole of the axial flux motor or generator, the first portion being a first angular portion of the annulus; and
a second magnet attached to a second portion of the support structure to form a second magnetic pole of the axial flux motor or generator, the second portion being a second angular portion of the annulus;
wherein:
the magnetic material of the support structure provides a flux return path from the first magnet to the second magnet via the first portion and the second portion,
the first portion of the support structure includes a first plurality of pocket features that are free of the magnetic material,
the first plurality of pocket features includes at least a first pocket feature, a second pocket feature adjacent the first pocket feature, a third pocket feature, and a fourth pocket feature adjacent the third pocket feature,
the first pocket feature and the second pocket feature are located at a first radial distance from a center of the annulus,
the third pocket feature and the fourth pocket feature are located at a second radial distance, different than the first radial distance, from the center of the annulus, and
a first distance between the first pocket feature and the second pocket feature is greater than a second distance between the third pocket feature and the fourth pocket feature.
26 . The rotor component of claim 25 , wherein the second radial distance is greater than the first radial distance.
27 . A rotor component configured for use in an axial flux motor or generator, comprising:
a support structure made of a magnetic material, the support structure forming an annulus;
a first magnet attached to a first portion of the support structure to form a first magnetic pole of the axial flux motor or generator, the first portion being a first angular portion of the annulus; and
a second magnet attached to a second portion of the support structure to form a second magnetic pole of the axial flux motor or generator, the second portion being a second angular portion of the annulus;
wherein:
the magnetic material of the support structure provides a flux return path from the first magnet to the second magnet via the first portion and the second portion,
the first portion of the support structure includes a first plurality of pocket features that are free of the magnetic material,
the first plurality of pocket features includes at least a first pocket feature having a first closed perimeter at a surface of the first portion and a second pocket feature having a second closed perimeter at the surface of the first portion,
the first pocket feature is located at a first radial distance from a center of the annulus,
the second pocket feature is located at a second radial distance, different than the first radial distance, from the center of the annulus, and
the first closed perimeter is greater than the second closed perimeter.
28 . The rotor component of claim 27 , wherein the first radial distance is greater than the second radial distance.
29 . The rotor component of claim 27 , wherein:
the first pocket feature has a first volume;
the second pocket feature has a second volume; and
the first volume is greater than the second volume.
30 . The rotor component of claim 29 , wherein the first radial distance is greater than the second radial distance.