Electric motor with integrated stator cooling passages and method of manufacture thereof
An electric motor includes a stator core and a plurality of stator windings disposed on or in the stator core, with the plurality of stator windings including a plurality of winding end-turns that extend out from the stator core. The electric motor also includes an electrically insulating potting material applied over the plurality of winding end-turns. A cooling passage is formed that defines a cooling circuit through which a cooling fluid is circulated to provide cooling to the plurality of winding end-turns, the cooling passage formed upon dissolving of a chemically soluble material embedded within the potting material.
1. An electric motor comprising:
a stator core;
a plurality of stator windings disposed on or in the stator core, the plurality of stator windings including a plurality of winding end-turns that extend out from the stator core;
an electrically insulating potting material applied over the plurality of winding end-turns; and
a cooling passage formed in the potting material immediately adjacent a portion of the plurality of winding end-turns that defines a cooling circuit through which a cooling fluid is circulated in direct contact with the portion of the plurality of winding end-turns to provide cooling to the plurality of winding end-turns, the cooling passage having an annular shape matching a configuration of the winding end-turns circumferentially disposed around the winding end-turns and varying in cross-section circumferentially around the winding end-turns, the cooling passage formed upon dissolving of a chemically soluble material embedded within the potting material.
2. The electric motor of claim 1 , wherein a first portion of the cooling passage has a first diameter and a second portion of the cooling passage has a second diameter different from the first diameter.
3. The electric motor of claim 1 , wherein the cooling passage has a serpentine configuration.
4. The electric motor of claim 1 , wherein the plurality of winding end-turns comprises:
a first set of winding end-turns extending out from a first end of the stator core; and
a second set of winding end-turns extending out from a second end of the stator core;
wherein the potting material comprises a first potting material applied over the first set of winding end-turns and a second potting material applied over the second set of winding end-turns.
5. The electric motor of claim 4 , wherein the cooling passage comprises:
a first cooling passage formed in the first potting material to define a first cooling circuit therethrough, the first cooling passage having an input and an output; and
a second cooling passage formed in the second potting material to define a second cooling circuit therethrough, the second cooling passage having an input and an output.
6. The electric motor of claim 1 , wherein the cooling passage forms a closed-loop, pressurized cooling circuit through which the cooling fluid is circulated.
7. The electric motor of claim 1 , wherein the chemically soluble material comprises a 3D printed material applied adjacent to a portion of the plurality of winding end-turns.
8. A method of manufacturing an electric motor, the method comprising:
providing a stator core;
positioning a plurality of stator windings on or in the stator core, the plurality of stator windings including a plurality of winding end-turns that extend out from the stator core;
applying a chemically soluble material adjacent to a portion of the plurality of winding end-turns directly onto the portion of the plurality of winding end-turns circumferentially around the winding end-turns in an annular shape matching a configuration of the winding end-turns and varying in cross-section circumferentially around the winding end-turns;
applying an electrically insulating potting material over the plurality of winding end-turns and the chemically soluble material; and
dissolving the chemically soluble material so as to form a cooling passage in the potting material immediately adjacent the portion of the plurality of winding end-turns that defines a cooling circuit through which a cooling fluid is circulated in direct contact with the portion of the plurality of winding end-turns to provide cooling to the plurality of winding end-turns.
9. The method of claim 8 , wherein dissolving the chemically soluble material comprises dissolving the chemically soluble material in a chemical solution bath.
10. The method of claim 8 , wherein applying the chemically soluble material comprises laying down a pre-formed annular tube adjacent to the portion of the plurality of winding end-turns.
11. The method of claim 8 , wherein applying the chemically soluble material comprises 3D printing a chemically soluble material adjacent to the portion of the plurality of winding end-turns.
12. The method of claim 11 , wherein 3D printing the chemically soluble material comprises:
3D printing a first portion of the chemically soluble material to have a first diameter; and
3D printing a second portion of the chemically soluble material to have a second diameter different from the first diameter.
13. The method of claim 11 , wherein 3D printing the chemically soluble material comprises 3D printing the chemically soluble material to have a serpentine shape.
14. The method of claim 8 , wherein the plurality of winding end-turns comprises a first set of winding end-turns extending out from a first end of the stator core and a second set of winding end-turns extending out from a second end of the stator core, with the potting material comprising a first potting material applied over the first set of winding end-turns and a second potting material applied over the second set of winding end-turns; and
wherein the forming the cooling passage comprises:
forming a first cooling passage in the first potting material to define a first cooling circuit therethrough, the first cooling passage having an input and an output; and
forming a second cooling passage in the second potting material to define a second cooling circuit therethrough, the second cooling passage having an input and an output.