Motor assembly with thermal ground plate

Abstract

An electric motor assembly includes an electric motor having a rotor and a stator surrounding the rotor, and an enclosure assembly disposed around the electric motor. The enclosure assembly has interconnected walls enclosing an internal volume sized for receiving the electric motor. One or more of the interconnected walls is defined by a heat-conducting plate that extends circumferentially to wrap around at least a portion of an outer perimeter of the stator. The heat- conducting plate includes a casing enclosing a cavity, the cavity containing a wicking layer, a vapor core, and a working fluid, the cavity having a pressure lower than that outside the enclosure.

Description

MOTOR ASSEMBLY WITH THERMAL GROUND PLATECROSS-REFERENCES TO RELATED APPLICATIONS

[0001] The present application claims priority benefit from United States patent application No. 63 / 600,944 filed on November 20, 2023, the entire content of which is incorporated by reference herein.TECHNICAL FIELD

[0002] The application relates to heat dissipation and, more particularly, to systems and methods used to dissipate heat generated by electric components such as electric motors.BACKGROUND

[0003] Electronic components, such as electric motors and controllers of such motors, often referred to as motor drives, generate heat during use. It may be required to dissipate this heat for proper functioning of the motor. More specifically, in certain situations elevated temperatures of internal components of an electric motor can limit the amount of torque and / or power generated by the electric motor. A higher torque and / or power may be reached with better thermal management of these motors. Existing systems may be satisfactory for their intended purposes, but improvements are sought.SUMMARY

[0004] There is accordingly provided an electric motor assembly, comprising: an electric motor having a rotor and a stator surrounding the rotor; and an enclosure assembly disposed around the electric motor, the enclosure assembly having interconnected walls enclosing an internal volume sized for receiving the electric motor, one or more of the interconnected walls defined by a heat-conducting plate that extends circumferentially to wrap around at least a portion of an outer perimeter of the stator, the heat-conducting plate including a casing enclosing a cavity, the cavity containing a wicking layer, a vapor core, and a working fluid, the cavity having a pressure lower than that outside the enclosure.

[0005] The electric motor assembly as defined above and described herein further includes, in certain embodiments, one or more of the following features, in whole or in part, and in any combination.

[0006] In certain embodiments, the heat-conducting plate has a concave side facing the stator and a convex side facing away from the stator.

[0007] In certain embodiments, a circumferential length of the heat-conducting plate is greater than a radial thickness of the heat-conducting plate.

[0008] In certain embodiments, fins protrude outwardly from the casing and away from the electric motor.

[0009] In certain embodiments, the fins are extruded form the casing and / or the casing is embossed to define successive crests and valleys, the fins corresponding to the crests.

[0010] In certain embodiments, the heat-conducting plate is mounted directly to the stator.

[0011] In certain embodiments, the electric motor assembly is devoid of a casing between the stator and the heat-conducting plate.

[0012] In certain embodiments, the heat-conducting plate includes two heat-conducting plates conjointly extending around a full circumference of the stator.

[0013] In certain embodiments, the electric motor assembly includes: a motor drive operatively connected to the electric motor and containing electronic components configured for controlling operation of the electric motor; and a drive heat-conducting plate mounted to the enclosure assembly and having a first section and a second section in heat exchange relationship with the first section, the motor drive mounted to the first section, the second section being offset from the first section, the motor drive being in heat exchange relationship with an environment via the drive heat-conducting plate.

[0014] In certain embodiments, the first section and the second section are transverse to one another.

[0015] In certain embodiments, the first section is disposed adjacent an end wall of the interconnected walls of the enclosure assembly, the end wall intersected by a rotation axis of the rotor.

[0016] In certain embodiments, the second section includes two second sections each extending circumferentially from the first section and away from one another.

[0017] In certain embodiments, the second section extends circumferentially a portion of a circumference of the electric motor.

[0018] In certain embodiments, the second section defines inner fins protruding inwardly towards the electric motor.

[0019] In certain embodiments, the motor heat-conducting plate extends circumferentially around a portion of the stator, a gap defined radially between the second section of the drive heat-conducting plate and the motor heat-conducting plate, the inner fins exposed to air flowing within the gap.

[0020] In certain embodiments, the first section is disposed over the heat-conducting plate, the second section disposed adjacent an end wall of the interconnected walls of the enclosure assembly, the end wall and the second section intersected by a rotation axis of the rotor.

[0021] In certain embodiments, the second section defines fins protruding towards the end wall.

[0022] In certain embodiments, the electronic components of the motor drive are mounted directly to the drive heat-conducting plate.

[0023] In certain embodiments, a fan configured for generating an airflow along the heat- conducting plate is provided.

[0024] In certain embodiments, the fan is drivingly engaged by the electric motor.

[0025] In certain embodiments, the electric components of the motor drive include one or more of: an AC / DC converter; a contactor; a chip; a semiconductor transistor; and insulated- gate bipolar transistor (IGBT).

[0026] There is also provided an electric machine assembly, comprising: an electric machine having a rotor and a stator; a liquid-cooled enclosure disposed around the electric machine, the liquid-cooled enclosure defining an inlet and an outlet fluidly connected to the inlet, the inlet fluidly connectable to a source of a liquid coolant; a heat-conducting plate mounted to the liquid-cooled enclosure, the heat-conducting plate being in heat exchange relationship with the liquid-cooled enclosure; and an electronics unit mounted to the liquid-cooled enclosure via the heat-conducting plate, the electronics unit including one or more electrical components, theheat-conducting plate providing heat exchange relationship between the electrical components of the electronics unit and the liquid-cooled enclosure.

[0027] The electric machine assembly as defined above and described herein further includes, in certain embodiments, one or more of the following features, in whole or in part, and in any combination.

[0028] In certain embodiments, the heat-conducting plate has a casing enclosing a cavity, the cavity containing a wicking layer, a vapor core, and a working fluid.

[0029] There is further provided an electric machine assembly, comprising: an electric motor having a rotor and a stator; an enclosure surrounding the rotor and the stator; a motor drive operatively connected to the electric motor and containing electronic components configured for controlling operation of the electric motor; and a drive heat-conducting plate mounted to the enclosure and having a first section and a second section in heat exchange relationship with the first section, the motor drive mounted to the first section, the second section being offset from the first section, the motor drive being in heat exchange relationship with an environment via the drive heat-conducting plate.

[0030] The electric machine assembly as defined above and described herein further includes, in certain embodiments, one or more of the following features, in whole or in part, and in any combination.

[0031] In certain embodiments, the first section and the second section are transverse to one another.

[0032] In certain embodiments, the first section is disposed adjacent an end wall of the enclosure, the end wall intersected by a rotation axis of the rotor.

[0033] The electric motor assembly of claim 25, wherein the second section includes two second sections each extending circumferentially from the first section and away from one another.

[0034] In certain embodiments, the second section extends circumferentially a portion of a circumference of the electric motor.

[0035] In certain embodiments, the second section defines inner fins protruding inwardly towards the electric motor.

[0036] In certain embodiments, the second section defines fins protruding towards an end wall of the enclosure.

[0037] In certain embodiments, the electronic components of the motor drive are mounted directly to the drive heat-conducting plate.

[0038] In certain embodiments, a fan is configured for generating an airflow along the heat- conducting plate.

[0039] In certain embodiments, the fan is drivingly engaged by the electric motor.

[0040] In certain embodiments, the electric components of the motor drive include one or more of: an AC / DC converter; a contactor; a chip; a semiconductor transistor; and insulated- gate bipolar transistor (IGBT).DESCRIPTION OF THE DRAWINGS

[0041] Reference is now made to the accompanying figures in which:

[0042] Fig. 1 is a schematic view of an electric motor in accordance with one embodiment;

[0043] Fig. 2A is a three dimensional view of an electric motor illustrating temperature contours on an outer casing of said motor;

[0044] Fig. 2B is a three dimensional view of a motor drive operatively connected to the electric motor of Fig. 2A and illustrating temperature contours on said motor drive;

[0045] Fig. 3A is a three dimensional view of an electric motor assembly including the electric motor of Fig. 1 having an enclosure configured to extract heat therefrom;

[0046] Fig. 3B is a three dimensional exploded view of the electric motor assembly of Fig. 1 ;

[0047] Fig. 3C is a schematic cross-sectional view of a heat-conducting plate of the enclosure of the electric motor assembly of Fig. 3A illustrating a process of heat exchange;

[0048] Fig. 4A is a three dimensional view of an electric motor assembly in accordance with another embodiment including the electric motor of Fig. 1 and a motor drive;

[0049] Fig. 4B is a three dimensional exploded view of the electric motor assembly of Fig. 4A;

[0050] Fig. 4C is a front view of the electric motor assembly of Fig. 4A;

[0051] Fig. 5A is a three dimensional view of an electric motor assembly in accordance with another embodiment including the electric motor of Fig. 1 and the motor drive;

[0052] Fig. 5B is a three dimensional exploded view of the electric motor assembly of Fig. 5A;

[0053] Fig. 5C is a front view of the electric motor assembly of Fig. 5A; and

[0054] Fig. 6A a three dimensional view of an electric motor assembly in accordance with yet another embodiment including the electric motor of Fig. 1 and the motor drive;

[0055] Fig. 6B is a three dimensional exploded view of the electric motor assembly of Fig. 6A;

[0056] Fig. 7 is a front view of an electric motor assembly in accordance with yet another embodiment;

[0057] Figs. 8A and 8B are three dimensional views illustrating different embodiments of fins;

[0058] Fig. 9 is a side view of a motor drive mounted to a heat-conducting plate; and

[0059] Fig. 10 is a schematic view of an electric motor assembly in accordance with another embodiment having a liquid-cooled enclosure.DETAILED DESCRIPTION

[0060] Referring to Fig. 1 , an electric machine is shown at 10. The electric machine 10 may, in certain embodiments, be an electric motor, such as of the reluctance type. Although an electric motor is depicted and will be generally described below, it is to be understood that the electric motor is an electric machine, and therefore the present disclosure also applies to other types ofelectrical machines, such as electric generators for example. The electric motor 10 may be a 60 Hz three-phase motor delivering a power of 7.5 HP at a rotational speed of 1800 RPM. Any kind of electric motors that may provide different power at a different speed and frequency may be used. The electric motor 10 includes a stator 1 1 and a rotor 12 rotatable relative to the stator 1 1 about a central axis. The rotor 12 is drivingly engaged to a shaft 13 to transmit power to a rotatable load. In some embodiments, a drive unit 14, or motor drive 14, is used to control operation of the electric motor 10. The drive unit 14 may include a plurality of electronic components, such as an AC / DC converter, and any other components required for proper operation of a synchronous reluctance motor. In other embodiments, the drive unit 14 may include other electrical components, such as contactors, chips, insulated-gate bipolar transistors (IGBTs), semiconductor power transistors (such as SiC or GaN), control electronics and the like. The drive conditions the power signal to send to the phases of the motor and can be used to operate the motor at variable speeds. There is interest in integrating the drive closely with the motor for ease of integration into applications that benefit from a variable speed motor. The motor drive 14 is shown here as being affixed to a rear side of the motor opposite the shaft 13. As will be shown below, other configurations are possible. For instance, the motor drive 14 may be secured to a cylindrical part of a casing of the motor 10. Additionally, the drive unit 14 may also be referred to herein more generally as an electronics unit, which includes one or more electrical components.

[0061] In this disclosure, expressions relating to axial, radial, and circumferential directions are in relationship to the rotation axis of the shaft 13 of the electric motor 10.

[0062] Referring to Fig. 2A, the electric motor 10 and its constituent components generate heat. Fig. 2A illustrate temperature contours and illustrates zone of higher temperatures denoted Z1 and zones of lower temperatures denoted Z2 for an electric motor not equipped with the cooling means of the present disclosure. The zones of lower temperatures Z2 may include axial extremities or ends of the electric motor 10. The labelled temperatures are exemplary only. Typically, such an electric motor has an outer casing, which may be made of steel or other suitable material. The outer casing becomes hot during use and may not be particularly well suited to dissipate the heat generated during operation of the electric motor. As shown in Fig. 2B, the motor drive 14 may also present a zone Z1 of higher temperature and a zone Z2 of lower temperature.

[0063] Referring to Figs. 3A-3B, an electric motor assembly is shown at 110. The electric motor assembly 110 includes the electric motor 10 described above and an enclosure assembly 20 disposed around the electric motor 10. The enclosure assembly 20 may be part of a cooling system of the electric motor assembly 110. The enclosure assembly 20 may thus at least partially alleviate issues pertaining to heat dissipation of the electric motor 10.

[0064] The enclosure assembly 20 includes interconnected walls that enclose an internal volume sized for receiving the electric motor 10. In the embodiment shown, the interconnect walls include two end walls 21 , 22 and a peripheral wall 23 extending from one of the two end walls 21 to the other 22 and extending around a rotation axis A1 of the electric motor 10.

[0065] One or more of the interconnected walls 21 , 22, 23 is defined by a motor heat- conducting plate 30. In the embodiment shown, the peripheral wall 23 of the enclosure assembly 20 is defined by two motor heat-conducting plates 30 each extending around about half of a circumference of the electric motor 10. Only one motor heat-conducting plate 30 extending around a full or partial circumference of the electric motor 10 may alternatively be used. More than two motor heat conducting plates 30 may be used. The heat-conducting plate 30 may define one or more of the two end walls 21 , 22 of the enclosure assembly 20. In other embodiments, the motor heat-conducting plate 30 may surround only a portion of a periphery of the electric motor 10. In some embodiments, a major portion of the periphery of the electric motor 10 may be surrounded by one or more motor heat-conducting plate(s) 30. Herein, the expression “major” implies 50% or more.

[0066] As shown in Fig. 3A, a fan 24 may be rotatably mounted to the end wall 22. The fan 24 may be drivingly engaged by the rotor of the electric motor 10, either directly or via a gearing arrangement. The fan 24 may drive an airflow around the heat-conducting plate 30 to help in extracting heat from the electric motor 10.

[0067] The motor heat-conducting plate(s) 30 is, in a particular embodiment, a thermal ground plate (TGP) for example one such as that described in International patent application No. PCT / CA2022 / 051825 filed December 15, 2022, the contents of which are incorporated by reference herein. The heat-conducting plates 30 as described herein may therefore also be referenced to as heat-conducting thermal ground plates, or simply thermal ground plates.

[0068] In one particular embodiment, the electric motor 10 may be devoid of a casing between the stator 11 and the motor heat-conducting plates 30. Put differently, in thisembodiment the heat-conducting plates 30 and the stator 11 are in direct contact with one another. In other words, the stator 1 1 may be secured or mounted to the heat-conducting plates 30, which therefore replaces the casing of the electric motor 10. There is no fluid gap between the heat conducting plates 30 and the stator 11. Any air or cooling fluid present therefore only flows above (outward of) the heat conducting plates 30. The motor heat-conducting plates 30 may define only a part of a casing of the motor. Stated differently, in one embodiment, the heat conducting plates 30 acts as the structural housing, in direct contact with the stator. In another embodiment, an existing steel motor housing can be present and in direct contact with the stator, and the motor heat-conducting plates 30 may be added over the housing. In this embodiment, therefore, the heat-conducting plates 30 cover an existing metal housing of the motor rather than replacing the casing or housing of the motor.

[0069] The motor heat-conducting plates 30 extend circumferentially to wrap around at least a portion of an outer perimeter of the stator of the electric motor 10. The motor heat-conducting plates 30, in this embodiment, include two halves each being semi-circularly shaped and both conjointly surrounding an entirety of the stator of the electric motor 30. The motor heat- conducting plates 30 may each extend a different circumferential length in some embodiments. The motor heat-conducting plates 30 extend axially relative to a rotation axis of the rotor of the electric motor 10 from a fore axial end proximate the output shaft to a rear axial end opposite the front axial end, and extends circumferentially from a first circumferential end to a second circumferential end being circumferentially offset from the first circumferential end. The motor heat-conducting plates 30 have each a concave side facing the stator and a convex side facing away from the stator. The concave side may be secured to the stator of the electric motor 10. The concave side extends around a portion of a circumference of the electric motor 10. A circumferential length of the motor heat-conducting plates 30 is greater than a radial thickness of the motor heat-conducting plates 30. The motor heat-conducting plate 30 may thus receive heat from a plurality of circumferential and axial positions on the electric motor 30. The description above may also apply to the drive heat-conducting plate(s), which are described below.

[0070] The motor heat-conducting plates 30 are configured to extract heat generated by the electric motor 10 and dissipate this heat to an environment E outside the electric motor 10. As shown in Fig. 3B, each of the two motor heat-conducting plates 30 extends half of a circumference of the electric motor 10 and are secured to one another via mating flanges, but any other ways of securing the motor heat-conducting plates 30 to the motor are contemplated.One of the motor heat-conducting plate 30 may extend more or less than half the circumference of the electric motor 10 in some configurations. A portion of the circumference of the electric motor 10 may be free from overlap with the motor heat-conducting plates 30.

[0071] As shown in Fig. 2A, the heat distribution on the electric motor 10 is not uniform in a circumferential direction around a central axis A1 of the electric motor 10. The motor heat- conducting plates 30 may thus extract heat from the zones Z1 of higher temperatures and move this heat in one or more of a circumferential direction and an axial direction relative to the central axis A1 and towards the zones Z2 of lower temperatures. The heat may then be evacuated to the environment over the increased larger hot surface, and potentially further enhanced via fins as will be discussed below. The fins may be omitted in some embodiments, but may be added to further increase the area of heat exchange with the environment E. The enclosure assembly 20 disclosed herein may thus be used to spread the heat more evenly around the electric motor 10 and to dissipate this heat to the environment E. The enclosure assembly 20 may thus mitigate hot spots and uneven temperature distribution on the electric motor 10. This may help reduce the enclosure assembly 20 temperature, which may be beneficial for the motor lifetime and / or may allow it to be operated at higher power / torque.

[0072] Referring now to Fig. 3C, one of the motor heat-conducting plate 30 is shown in greater detail. The motor heat-conducting plate 30 includes a casing, herein including an inner casing 31 and an outer casing 32 spaced apart from the inner casing 31. The inner and outer casings may be metallic, but any other suitable material may be used. Such other materials may include, for instance, a polymer or plastic, amongst other possibilities. The inner and outer casings 31 , 32 of the heat-conducting plate 30 do not need to be able to provide heat conductivity. The inner casing 31 is exposed to heat generated by the electric motor 10. As discussed above with reference to Fig. 2A, the heat generated by the electric motor 10 is not uniform circumferentially. Hence, a central section 30A of the motor heat-conducting plate 30 may be exposed to more heat than lateral sections 30B of the inner casing 31 . The motor heat- conducting plate 30 includes an inner wicking layer 33 adjacent the inner casing 31 and an outer wicking layer 34 adjacent the outer casing 32. A cavity 35 is located between the inner casing 31 and the outer casing 32. The cavity 35 is subjected to a vacuum, such that the pressure inside this cavity 35 is lower than that outside the cavity 35 (e.g., a negative pressure). The first and second casings 31 , 32 may be joined together along their respective peripheries as well as potentially supported at other locations within the periphery. A vapor core 36 is located within the cavity 35 between the inner wicking layer 33 and the outer wicking layer 34. It will beappreciated that, in some configurations, only one wicking layer may be used. This single wicking layer may be attached to a surface of the casing. The single wicking layer may span an entire thickness of the cavity 35 such as to touch surfaces of both casings. The surfaces of the inner and outer casings may be provided with grooves to let the vapor flow. The wicking layer is made of a material having a porosity or a porous structure that facilitates heat transfer by enabling a movement of a working liquid via capillary action.

[0073] The motor heat-conducting plate 30 is operable to move the heat from the central section 30A to the lateral sections 30B. However, it is appreciated that the motor heat- conducting plate 30 may move heat from a first section towards a second section being circumferentially and / or axially offset from the first section. The example of the heat being moved from the central section 30A to the lateral sections 30B is merely to explain a principle of operation of the motor heat-conducting plate 30. A working fluid is present in liquid form in the inner and outer wicking layers 33, 34. The working fluid may be water, acetone, or another suitable working fluid. When exposed to the heat, the working fluid evaporates in a gaseous phase and migrates, into the cavity 35, which contains the vapor core 36. The working fluid in gaseous phase then migrates along the vapor core 36 towards the lateral sections 30B of the motor heat-conducting plate 30. Since the second sections 30B are colder than the first section 30A, the working fluid condensates back into a liquid phase and gets absorbed by the wicking layers 33, 34. Then, the working fluid moves, by capillary action, along the wicking layers 33, 34 and migrates back towards the central section 30A and the process starts over again. The motor heat-conducting plate 30 therefore removes heat from the central section 30A by evaporating the working fluid and transfers heat to the lateral sections 30B by condensing the working fluid. These phase changes result in heat being moved in a circumferential and / or axial direction. The phase change may be used to provide high heat absorption and release. The vapor or liquid flow may be used to move heat quickly.

[0074] In the embodiment shown, fins 37 are disposed overthe outer casing 32 of the motor heat-conducting plate 30. The fins 37 protrude outwardly from the casing, herein from the outer casing 32, and away from the electric motor 10. Air or liquid cooling flows around the outer casing, transferring the heat from the outer casing to the cooling flow. The coolant flow may be the ambient air or a fluid provided for cooling. In the later, an additional external housing or ducting may be added to confine the coolant flow to the outer surface of the casing.

[0075] Referring now to Figs. 4A-4B, another embodiment of an electric motor assembly is shown at 210. For the sake of conciseness, only features differing from the electric motor assembly 110 described above with reference to Figs. 3A-3C are described below.

[0076] In the embodiment shown, furtherto the motor heat-conducting plates 30, the electric motor assembly 210 includes the motor drive 14 operatively connected to the electric motor 10 and configured for controlling operation of the electric motor 10. It will be appreciated that the motor heat-conducting plates 30 may be omitted in this configuration. The motor drive 14 includes electronic components 14A, such as an AC / DC converter, a contactor, a chip, a semiconductor transistor, insulated-gate bipolar transistor (IGBT), a controller, an inverter, semiconductor transistor, etc. These electronic components 14A are known to generate heat, which may require dissipation. To this end, the electric motor assembly 210 includes a drive heat-conducting plate 40 mounted to the enclosure assembly 20 and having a first section 41 and a second section 42 in heat exchange relationship with the first section 41 . The motor drive 14 is mounted to the first section 41 . The second section 42 is offset from the first section 41 . In other words, the second section 42 is not overlapped by the motor drive 14. The motor drive 14 is thus in heat exchange relationship with an environment outside the electric motor assembly 210 via the drive heat-conducting plate 40. In the embodiment shown, the first section 41 is in abutment against the motor drive 14 such that heat may be conductively transmitted from the motor drive 14 to the drive heat-conducting plate 40.

[0077] The drive heat-conducting plate 40 also includes the same components of the motor heat-conducting plate 30 described above, that is, the casing, wicking layer, vapor core, and working fluid. The drive heat-conducting plate 40 thus also works on the principle of phase changes of the working fluid to move heat between the two sections 41 , 42.

[0078] In the depicted embodiment, the first section 41 and the second section 42 are transverse to one another, but other configurations are contemplated. For instance, the two sections may be axially, radially, and / or circumferentially offset from one another in some embodiments. The heat may thus move from the first section 41 to the second section 42. The first section 41 is disposed adjacent one of the end walls 21 , 22 of the interconnected walls of the enclosure assembly 20. Thus, the motor drive 14 may be located at a rear of the electric motor 10. As shown, a fan 24 may be rollingly mounted to the end wall 22. The first section 41 of the drive heat-conducting plate 40 may face the fan 24. An airflow generated by the fan 24 may contribute to the extraction of heat from the second section 42. The fan 24 may be drivinglyengaged by the electric motor 10, either directly or via a gearbox, or it may be another fan powered by another actuator / motor. An HVAC system may be used to provide cool air to extract the heat. In some embodiments, another fluid may be used to extract heat from the motor 10. Such other fluids may be, for instance, water, oil, or another suitable fluid.

[0079] Referring now to Fig. 4C, as illustrated, the second section 42 of the drive heat- conducting plate 40 extends at least partially circumferentially around the electric motor 10 and circumferentially overlaps one or more of the two motor heat-conducting plates 30. A gap G is located radially between the motor heat-conducting plate 30 and the second section 42 of the drive heat-conducting plate 40. This gap G is in fluid communication with the environment E such that air may flow within the gap G. This air may be pushed with the fan 24 described above. In other words, the drive heat-conducting plate 40 and the motor heat-conducting plates 30 may be thermally decoupled from one another. Put differently, there may be substantially no heat exchange between the drive heat-conducting plate 40 and the motor heat-conducting plates 30. However, the motor heat-conducting plates 30 and the drive heat-conducting plate 40 may be mechanically coupled to one another.

[0080] As shown in Fig. 4C, the second section 42 of the drive heat-conducting plate 40 has a central portion 42A and two side portions 42B each protruding circumferentially away from one another and from the central portion 42A. The two side portions 42B each define inner fins 47A and outer fins 47B. In some embodiments, the central portion 42A may define one or more of the inner and outer fins 47A,47B. The inner fins 47A protrude inwardly towards the electric motor 10 whereas the outer fins 47B protrude outwardly away from the electric motor 10. The inner fins 47A are thus exposed to air flowing within the gap G between the second section 42 of the drive heat-conducting plate 40 and the motor heat-conducting plate 30.

[0081] The second section 42 of the drive heat-conducting plate 40 is secured to the electric motor 10 at junctions between the two motor-heat conducting plates 30. More specifically, fasteners 25 may be used to connecting opposed circumferential edges of the second section 42 to the electric motor 10. These fasteners 25 may also act as spacers to ensure that no contact occurs between the drive and motor heat-conducting plates 40, 30 to maintain the gap G.

[0082] Referring now to Figs. 5A-5C, another embodiment of an electric motor assembly is shown at 310. For the sake of conciseness, only features differing from the electric motorassembly 210 described above with reference to Figs. 4A-4C are described below. Again, in this configuration, it will be appreciated that the motor heat-conducting plates 30 may be omitted.

[0083] In the embodiment shown, the motor drive 14 is disposed between the end walls of the enclosure assembly 20 of the electric motor assembly 210. In other words, the motor drive 14 axially overlaps the rotor / stator of the electric motor 10. Another embodiment of a drive heat- conducting plate is shown at 140 and used to extract heat from the motor drive 14.

[0084] In this configuration, the drive heat-conducting plate 140 includes a first section 141 and two second sections 142 disposed on opposite sides of the first section 141 . In other words, each of the two sections 142 extend from the first section 141 and extend away from the other of the two second sections 142. The motor drive 14 is mounted to the first section 141 . Each of the two second sections 142 extend circumferentially a portion of a circumference of the electric motor 10. As shown in Fig. 5C, the inner fins overlap both of the two second section 142 and the first section 141 . These inner fins are exposed to a gap between the motor heat-conducting plate 30 and the drive heat-conducting plate 140 as described above.

[0085] Referring now to Figs. 6A-6B, another embodiment of an electric motor assembly is shown at 410. For the sake of conciseness, only features differing from the electric motor assembly 110 of Figs. 3A-3C are described below. It will be appreciated that the motor heat- conducting plates 30 may in certain embodiments be omitted in this configuration, in which case the drive heat-conducting plates 240 are provided but not the motor heat-conducting plates 30.

[0086] In the depicted embodiment, the drive heat-conducting plate 240 includes a first section 241 and a second section 242 extending transversally to the first section 241. In other words, the two sections define an L-shape. The motor drive 14 is secured to the first section 241 . The first section 241 is axially overlapping the electric motor 10. The second section 242 is facing the end wall 22 of the enclosure assembly 20. Fins 48 protrude from the second section 242 towards the electric motor 10. The fins 48 are thus exposed to an air flow generated by the fan 24. Apertures 242A may be defined through the second section 242 of the drive heat- conducting plate 240 to allow air to flow there through. The second section 242 is herein intersected by a rotation axis of the electric motor 10.

[0087] Referring now to Fig. 7, the drive heat-conducting plate 140 is disposed around the electric motor 10 and may be fastened to a casing 15 of the electric motor 10. This casing 15 may be a simple sheet metal casing. As shown, spacers 26 are disposed at different locationsbetween the drive heat-conducting plate 140 and the casing 15 of the electric motor 10. Fins 49 may protrude from a casing of the drive heat-conducting plate 140 and extend towards the casing 15 of the electric motor 10. The fins 49 may vary in length around a periphery of the electric motor 10. In other words, the fins 49 being in register with the motor drive 14 may be shorter to keep a distance between the electric motor 10 and the motor drive 14 as small as possible. The length of the spacers may be adjusted accordingly. Hence, the gap between the heat-conducting plate and the casing 15 may be non-uniform in a circumferential direction around a rotation axis of the electric motor 10.

[0088] Referring now to Figs. 8A and 8B, different embodiments of fins are shown. In the configuration of Fig. 8A, the fins 48, which are also shown in Fig. 6A, are cylindrically-shaped fins extruded from a casing of the heat-conducting plate. Other shapes are contemplated. The fins may be blade fins as shown in Fig. 7, rectangular fins, and so on. In Fig. 8B, the fins 148 may be defined an embossing imparted to the casing of the heat-conducting plate. For instance, the casing may define a series of interspaced crests 148A and valleys 148B, the fins 148 may be defined by the crests 148A. These fins 148 may have a substantially triangular shape, but other shapes are contemplated.

[0089] Referring now to Fig. 9, in some embodiments, the motor drive 14 itself includes an enclosure 14B enclosing the electronic components 14A. The enclosure 14B may include a base plate 14C to which the electric components 14A are affixed. This base plate 14C may be in direct contact against the drive heat-conducting plate 40, 140, 240. This direct contact may minimize a thermal resistance therebetween to promote heat transfer from the electronic components 14A to the environment via the drive heat-conducting plate 40, 140, 240. However, it will be appreciated that the base plate 14C may be omitted and the electric components 14A may be mounted directly to the drive heat-conducting plate 40, 140, 240. A thermal interface material (TIM) may be placed between the drive heat-conducting plate 40, 140, 240 and the motor drive 14 and / or between the motor heat-conducting plate and the motor to provide a good thermal contact between these components. This may minimize a thermal resistance between t

[0090] Referring now to Fig. 10, another electric motor assembly is shown at 510 and includes the electric motor 10 and the motor drive 14. In this embodiment, the electric motor 10 is liquid cooled. More specifically, the electric motor 10 includes a liquid-cooled enclosure 120 that defines flow passages 121 therein for flowing a liquid coolant, such as a mixture of water and glycol, although any suitable liquid coolant may be used. The liquid-cooled enclosure 120has an inlet 122 and an outlet 123, both fluidly connected to one another, to the coolant passages 121 and to a source S of a coolant. Although not illustrated, a pump or other flowinducing means are used to induce a flow of the coolant from the inlet 122 to the outlet 123 through the coolant passages 121. This flow inducing means may be powered by the electric motor 10 itself. The coolant passages 121 may be a single annular passage extending around the electric motor 10. In some embodiments, a plurality of passages may be defined and may extend axially, radially, and / or circumferentially. Any configuration is contemplated.

[0091] The motor drive 14 is herein secured to the liquid-cooled enclosure 120 via a heat- conducting plate 340, which operates similarly as the other heat-conducting plates described above. Therefore, heat generated by the electronic components of the motor drive 14 is transmitted to the coolant via the heat-conducting plate 340. In this embodiment, the motor drive 14 is disposed to axially overlap the electric motor 10, but may alternatively be located adjacent one of the end walls of the enclosure 120.

[0092] The disclosed electric motor assemblies and their respective enclosures including heat-conducting plates may spread heat over the entire casing, increase the surface for heat exchange, allow increase of the heat generated by the motor and, thus the increase of the power of the motor. They may increase the heat exchange surface of the motor drive 14 by 800%. The disclosed assemblies may provide a cooling power of 500 W. Copper cladded stainless steel may be used for the casings of the second heat-conducting plate 40 and the motor heat- conducting plates 30. A thickness of the casing may be about 0.09 inch, but may be varied in some applications.

[0093] It is noted that various connections are set forth between elements in the preceding description and in the drawings. It is noted that these connections are general and, unless specified otherwise, may be direct or indirect and that this specification is not intended to be limiting in this respect. A coupling between two or more entities may refer to a direct connection or an indirect connection. An indirect connection may incorporate one or more intervening entities. The term “connected” or "coupled to" may therefore include both direct coupling (in which two elements that are coupled to each other contact each other) and indirect coupling (in which at least one additional element is located between the two elements).

[0094] It is further noted that various method or process steps for embodiments of the present disclosure are described in the following description and drawings. The description maypresent the method and / or process steps as a particular sequence. However, to the extent that the method or process does not rely on the particular order of steps set forth herein, the method or process should not be limited to the particular sequence of steps described. As one of ordinary skill in the art would appreciate, other sequences of steps may be possible. Therefore, the particular order of the steps set forth in the description should not be construed as a limitation.

[0095] Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whetherthe element, component, or method step is explicitly recited in the claims. As used herein, the terms “comprises”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0096] While various aspects of the present disclosure have been disclosed, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the present disclosure. For example, the present disclosure as described herein includes several aspects and embodiments that include particular features. Although these particular features may be described individually, it is within the scope of the present disclosure that some or all of these features may be combined with any one of the aspects and remain within the scope of the present disclosure. References to “various embodiments,” “one embodiment,” “an embodiment,” “an example embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. The use of the indefinite article “a” as used herein with reference to a particular element is intended to encompass “one or more” such elements, and similarly the use of the definite article “the” in reference to a particular element is not intended to exclude the possibility that multiple of such elements may be present.

[0097] The embodiments described in this document provide non-limiting examples of possible implementations of the present technology. Upon review of the present disclosure, a person of ordinary skill in the art will recognize that changes may be made to the embodiments described herein without departing from the scope of the present technology. Yet furthermodifications could be implemented by a person of ordinary skill in the art in view of the present disclosure, which modifications would be within the scope of the present technology.

Claims

CLAIMS1 . An electric motor assembly, comprising: an electric motor having a rotor and a stator surrounding the rotor; and an enclosure assembly disposed around the electric motor, the enclosure assembly having interconnected walls enclosing an internal volume sized for receiving the electric motor, one or more of the interconnected walls defined by a heat- conducting plate that extends circumferentially to wrap around at least a portion of an outer perimeter of the stator, the heat-conducting plate including a casing enclosing a cavity, the cavity containing a wicking layer, a vapor core, and a working fluid, the cavity having a pressure lower than that outside the enclosure assembly.

2. The electric motor assembly of claim 1 , wherein the heat-conducting plate has a concave side facing the stator and a convex side facing away from the stator.

3. The electric motor of claim 1 or 2, wherein a circumferential length of the heat-conducting plate is greater than a radial thickness of the heat-conducting plate.

4. The electric motor assembly of any one of claims 1 to 3, further comprising fins protruding outwardly from the casing and away from the electric motor.

5. The electric motor assembly of claim 4, wherein one or more of: the fins are extruded form the casing; and the casing is embossed to define successive crests and valleys, the fins corresponding to the crests.

6. The electric motor assembly of any one of claims 1 to 5, wherein the heat-conducting plate is mounted directly to the stator.

7. The electric motor assembly of claim 6, wherein the electric motor assembly is devoid of a casing between the stator and the heat-conducting plate.

8. The electric motor assembly of any one of claims 1 to 7, wherein the heat-conducting plate includes two heat-conducting plates conjointly extending around a full circumference of the stator.

9. The electric motor assembly of claim 1 , comprising: a motor drive operatively connected to the electric motor and containing electronic components configured for controlling operation of the electric motor; and a drive heat-conducting plate mounted to the enclosure assembly and having a first section and a second section in heat exchange relationship with the first section, the motor drive mounted to the first section, the second section being offset from the first section, the motor drive being in heat exchange relationship with an environment via the drive heat-conducting plate.

10. The electric motor assembly of claim 9, wherein the first section and the second section are transverse to one another.11 . The electric motor assembly of claim 10, wherein the first section is disposed adjacent an end wall of the interconnected walls of the enclosure assembly, the end wall intersected by a rotation axis of the rotor.

12. The electric motor assembly of claim 10, wherein the second section includes two second sections each extending circumferentially from the first section and away from one another.

13. The electric motor assembly of claim 11 or 12, wherein the second section extends circumferentially about a portion of a circumference of the electric motor.

14. The electric motor assembly of claim 13, wherein the second section defines inner fins protruding inwardly towards the electric motor.

15. The electric motor assembly of claim 14, wherein the motor heat-conducting plate extends circumferentially around a portion of the stator, a gap defined radially between the second section of the drive heat-conducting plate and the motor heat-conducting plate, the inner fins exposed to air flowing within the gap.

16. The electric motor assembly of claim 10, wherein the first section is disposed over the heat-conducting plate, the second section disposed adjacent an end wall of the interconnected walls of the enclosure assembly, the end wall and the second section intersected by a rotation axis of the rotor.

17. The electric motor assembly of claim 16, wherein the second section defines fins protruding towards the end wall.

18. The electric motor assembly of any one of claims 9 to 17, wherein the electronic components of the motor drive are mounted directly to the drive heat-conducting plate.

19. The electric motor assembly of any one of claims 1 to 18, comprising a fan configured for generating an airflow along the heat-conducting plate.

20. The electric motor assembly of claim 19, wherein the fan is drivingly engaged by the electric motor.

21. The electric motor assembly of any one of claims 9 to 20, wherein the electric components of the motor drive include one or more of: an AC / DC converter; a contactor; a chip; a semiconductor transistor; and insulated-gate bipolar transistor (IGBT).

22. An electric machine assembly, comprising: an electric machine having a rotor and a stator; a liquid-cooled enclosure disposed around the electric machine, the liquid-cooled enclosure defining an inlet and an outlet fluidly connected to the inlet, the inlet fluidly connectable to a source of a liquid coolant; a heat-conducting plate mounted to the liquid-cooled enclosure, the heat-conducting plate being in heat exchange relationship with the liquid-cooled enclosure; and an electronics unit mounted to the liquid-cooled enclosure via the heat-conducting plate, the electronics unit including one or more electrical components, the heat- conducting plate providing heat exchange relationship between the electrical components of the electronics unit and the liquid-cooled enclosure.

23. The electric machine assembly of claim 22, wherein the heat-conducting plate has a casing enclosing a cavity, the cavity containing a wicking layer, a vapor core, and a working fluid.

24. An electric machine assembly, comprising: an electric motor having a rotor and a stator; an enclosure surrounding the rotor and the stator;a motor drive operatively connected to the electric motor and containing electronic components configured for controlling operation of the electric motor; and a drive heat-conducting plate mounted to the enclosure and having a first section and a second section in heat exchange relationship with the first section, the motor drive mounted to the first section, the second section being offset from the first section, the motor drive being in heat exchange relationship with an environment via the drive heat-conducting plate.

25. The electric machine assembly of claim 24, wherein the first section and the second section are transverse to one another.

26. The electric machine assembly of claim 25, wherein the first section is disposed adjacent an end wall of the enclosure, the end wall intersected by a rotation axis of the rotor.

27. The electric machine assembly of claim 25, wherein the second section includes two second sections each extending circumferentially from the first section and away from one another.

28. The electric machine assembly of claim 26 or 27, wherein the second section extends circumferentially a portion of a circumference of the electric motor.

29. The electric machine assembly of claim 28, wherein the second section defines inner fins protruding inwardly towards the electric motor.

30. The electric machine assembly of claim 24, wherein the second section defines fins protruding towards an end wall of the enclosure.

31. The electric machine assembly of any one of claims 24 to 30, wherein the electronic components of the motor drive are mounted directly to the drive heat-conducting plate.

32. The electric machine assembly of any one of claims 24 to 31 , comprising a fan configured for generating an airflow along the drive heat-conducting plate.

33. The electric machine assembly of claim 32, wherein the fan is drivingly engaged by the electric motor.

34. The electric machine assembly of any one of claims 24 to 33, wherein the electric components of the motor drive include one or more of: an AC / DC converter; a contactor; a chip; a semiconductor transistor; and insulated-gate bipolar transistor (IGBT).

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