Structural stator core

Patent metadata

Field	Value
Publication number	US-12562614-B2
Application number	US-202318467586-A
Country	US
Kind code	B2
Filing date	Sep 14, 2023
Priority date	Sep 15, 2022
Publication date	Feb 24, 2026
Grant date	Feb 24, 2026

Abstract

Electric motors and related methods employ a stator assembly as part of a housing assembly that reacts output shaft loads to a mounting base. An electric motor includes an output shaft, a rotor coupled to the output shaft, a first housing, a first bearing assembly coupled to the first housing, a second housing, a second bearing assembly coupled to the second housing, and a stator assembly. The stator assembly includes a structural stator core member and stator coils. The structural stator core member extends circumferentially around the output shaft. The second housing is coupled to the first housing by the stator core.

First claim

What is claimed is:

1 . An electric motor comprising:
an output shaft having an output shaft rotational axis; a rotor coupled to the output shaft; a first housing comprising first housing-to-stator attachment features; a first bearing assembly coupled to the first housing and interfaced with a first section of the output shaft; a second housing comprising second housing-to-stator attachment features; a second bearing assembly coupled to the second housing and interfaced with a second section the output shaft; a stator assembly comprising a stator core and stator coils, wherein the stator core comprises a stator back iron, stator teeth, and stator-to-housing attachment features, wherein the second housing is coupled to the first housing by the stator core via the second housing-to-stator attachment features, the first housing-to-stator attachment features, and the stator-to-housing attachment features; wherein the stator back iron extends circumferentially around the output shaft rotational axis and is configured to react one or more interface forces applied to the second bearing assembly by the second section of the output shaft to the first housing, wherein each of the stator teeth extend radially inward toward the output shaft rotational axis from the stator back iron; and wherein each of the stator coils extends circumferentially around a respective one of the stator teeth; and
cooling fins bonded to an outer-circumferential surface of the stator back iron via a thermally conductive adhesive.

2 . The electric motor of claim 1 , wherein:
the first bearing assembly is configured to react one or more first bearing assembly radial loads from the first section of the output shaft into the first housing; each of the one or more first bearing assembly radial loads is oriented radially relative to the output shaft rotational axis; the first bearing assembly is configured to react a thrust load from the output shaft into the first housing; and the thrust load is aligned with the output shaft rotational axis.

3 . The electric motor of claim 2 , wherein:
the second bearing assembly is configured to react one or more second bearing assembly radial loads from the second section of the output shaft into the second housing; and each of the one or more second bearing assembly radial loads is oriented radially relative to the output shaft rotational axis.

4 . The electric motor of claim 3 , wherein the first housing comprises one or more motor mounting features configured for mounting the electric motor to a mounting base.

5 . The electric motor of claim 1 , further comprising stator attachment bolts and wherein:
the stator-to-housing attachment features comprise stator-to-housing attachment fastener holes; the first housing-to-stator attachment features comprise first housing-to-stator attachment fastener holes; the second housing-to-stator attachment features comprise second housing-to-stator attachment fastener holes; and each of the stator attachment bolts extends through a respective one of the first housing-to-stator attachment fastener holes, a respective one of the second housing-to-stator attachment fastener holes, and a respective one of the stator-to-housing attachment fastener holes.

6 . The electric motor of claim 1 , wherein the rotor comprises permanent magnets.

7 . The electric motor of claim 1 , wherein the stator back iron, the stator teeth, and the stator-to-housing attachment features are formed of a magnetically permeable material.

8 . An aircraft comprising the electric motor of claim 1 .

9 . The aircraft of claim 8 , wherein the output shaft is drivingly coupled with a lift fan of the aircraft.

10 . A method of supporting an output shaft of an electric motor, the method comprising:
supporting the output shaft with a first bearing assembly and a second bearing assembly offset from the first bearing assembly along a rotational axis of the output shaft; supporting the first bearing assembly via a first housing to which the first bearing assembly is coupled; supporting the first housing via a mounting base via attachment of the first housing to the mounting base; supporting the second bearing assembly via a second housing to which the second bearing assembly is coupled, wherein the second housing is offset from the first housing along the rotational axis of the output shaft; supporting a stator assembly by the first housing via attachment of a first end of the stator assembly to the first housing; and supporting the second housing by the stator assembly via attachment of the second housing to a second end the stator assembly, wherein the second end of the stator assembly is opposite to the first end of the stator assembly; and attaching cooling fins to an outer-circumferential surface of a stator back iron, wherein the cooling fins are bonded to the outer-circumferential surface via a thermally conductive adhesive.

11 . The method of claim 10 , further comprising:
transmitting a first bearing assembly load from the output shaft to the mounting base through a first load path that extends through the first bearing assembly and the first housing to the mounting base; and transmitting a second bearing assembly load from the output shaft to the mounting base through a second load path that extends through the second bearing assembly, the second housing, the stator assembly, and the first housing to the mounting base.

12 . The method of claim 11 , wherein:
the second bearing assembly load is oriented radially relative to the rotational axis of the output shaft; the first bearing assembly load comprise a radial load component and a thrust load component; the radial load component is oriented radially relative to the rotational axis of the output shaft; and the thrust load component is aligned with the rotational axis of the output shaft.

13 . The method of claim 10 , wherein:
the stator assembly comprises a stator core and stator coils; the stator core comprises a stator back iron, stator teeth, and stator-to-housing attachment features; and the stator core is coupled with and between the first housing and the second housing via the stator-to-housing attachment features.

14 . The method of claim 10 , wherein the output shaft is drivingly coupled with a lift fan of an aircraft.

15 . A method of cooling an electric motor, the method comprising:
supporting a first bearing assembly for an output shaft of the electric motor via a first housing to which the first bearing assembly is coupled; supporting a second bearing assembly for the output shaft via a second housing to which the second bearing assembly is coupled; maintaining engagement between a first end of a stator assembly and the first housing via attachment of the first end of the stator assembly to the first housing; maintaining engagement between a second end of the stator assembly and the second housing via attachment of the second end of the stator assembly to the second housing; supporting cooling fins attached to the stator assembly so that the cooling fins are exposed to air that is not enclosed by the first housing, the second housing, and the stator assembly; and cooling the electric motor by conducting heat from the stator assembly into the cooling fins, wherein the cooling fins are thermally coupled to an outer-circumferential surface of a stator back iron via a thermally conductive adhesive.

16 . The method of claim 15 , wherein:
the stator assembly comprises a stator core and stator coils; wherein the stator core comprises a stator back iron

Assignees

• Wisk Aero Llc

Inventors

• Saranadhi Dhananjai

Classifications

• H02K5/18

  with ribs or fins for improving heat transfer · CPC title

• H02K21/14

  with magnets rotating within the armatures · CPC title

• H02K7/083

  radially supporting the rotary shaft at both ends of the rotor (H02K7/086, H02K7/09 take precedence) · CPC title

• B64D27/24

  using steam or spring force (jet aircraft B64D27/16) · CPC title

• H02K1/185

  to outer stators · CPC title