A motor assembly with active cooling

Abstract

Embodiments herein disclose a motor assembly (100), comprising a housing (150), a motor control unit (MCU) (122), and a motor end cover (106). The MCU comprises a printed circuit board (PCB) (124), at least one electronic component (126), and a controller (130) operatively coupled to the at least one electronic component. The motor end cover comprises a single-flow coolant path (108) that is directly drilled into a casing of the motor end cover. The motor end cover comprises a projection (114) arranged along the coolant path, and an inlet (110) and an outlet (112) through which a coolant medium can enter and exit the motor end cover, respectively. The projection, which is thermally connected to the at least one electronic component, supports the at least one electronic component and enables it to be cooled when the coolant medium flows across the coolant path in the motor end cover.

Description

A MOTOR ASSEMBLY WITH ACTIVE COOLINGTechnical Field:

[0001] The present disclosure relates to electric vehicles, and more particularly relates to a motor assembly, in an electric vehicle, with active cooling.Background:

[0002] Devices such as electric vehicles include electric motors that propel a vehicle. The electric motors work on the principle of converting electrical energy into mechanical energy. The electric vehicle may have a power source, such as a battery pack, that supplies the electrical energy to the motor. Motors have a control unit comprising electronic components for controlling the amount of electrical energy being directed to the motor. The electrical components generate heat as a result of their operation, due to which they need to be cooled down. In traditional motor control units, different casings were used to create a coolant path which requires seal, precision machining in casing for seating of the seal and a locator pin. Additionally, the construction of such motor control units required more parts, a longer assembly process, and as such was more expensive. Therefore, it would be desirable to facilitate the cooling of these electronic components in a cost- effective manner, less cumbersome, and reliable manner.Summary:

[0003] These and other problems are generally solved or circumvented, and technical advantages are generally achieved, by advantageous embodiments of the present disclosure.

[0004] A summary of certain embodiments disclosed herein is set forth below. It should be understood that these aspects are presented merely to provide the reader with a brief summary of these certain embodiments and that these aspects are not intended to limit thescope of this disclosure. Indeed, this disclosure may encompass a variety of aspects that may not be set forth below.

[0005] According to an embodiment of the present disclosure, a motor assembly is provided. The motor assembly comprises a housing, a motor control unit, and a motor end cover. The motor control unit comprises a printed circuit board, at least one electronic component, that generates heat, on a top side of the printed circuit board, and a controller mounted on the top side of the printed circuit board and operatively coupled to the at least one electronic component. The motor end cover is attached to a side of the housing, and comprises a single-flow coolant path, at least one projection located on a top side of the motor end cover and arranged along with the single-flow coolant path, an inlet, and an outlet. The single-flow coolant path is directly drilled into a casing of the motor end cover. A coolant medium enters the motor end cover and flows through the single-flow coolant path via an inlet, and exits the motor end cover via an outlet. The top side of the printed circuit board is directly placed on the motor end cover such that the at least one projection supports the at least one electronic component located on the top side of the PCB.Brief Description of Drawings:

[0006] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and components.FIGS. 1A and IB illustrate a view of the top side and bottom side of the integrated motor control unit (MCU), respectively, according to an embodiment of the present disclosure;FIGS. 2A and 2B illustrate an integrated MCU without the top cover removed to show a triangular-shaped single-flow coolant path, having an inlet and an outlet disposed on the same side of the housing, with the inlet and outlet being situated within an end cover of the integrated MCU according to an embodiment of the present disclosure;FIGS. 3A, 3B, and 3C illustrate a top view of the motor end cover with the triangularshaped single-flow coolant path, a top view of the motor end cover with projections along the triangular-shaped single-flow coolant path, and a front view of the motor end cover, respectively, according to an embodiment of the present disclosure;FIG. 4 illustrates a view of the motor end cover with a coolant path drilled into the casing of the motor end cover, and three V-shaped projections situated along the coolant path, according to an embodiment of the present disclosure;FIGS. 5A and 5B illustrate a view of the motor end cover with a rectangular-shaped single-flow coolant path drilled into the casing of the motor end cover, according to another embodiment of the present disclosure;FIG. 6 illustrates a top view of a top side of a motor control unit, according to an embodiment of the present disclosure;FIG. 7 illustrates the contact between at least one electronic component in the printed circuit board and a coolant pipe that enables cooling of the at least one electronic component in the printed circuit board, according to an embodiment of the present disclosure;FIG. 8 illustrates a bottom side of the printed circuit board in the motor control unit, according to an embodiment of the present disclosure;FIG. 9 illustrates a sectional view of the integrated MCU, according to an embodiment of the present disclosure; andFIG. 10 illustrates the connection of the motor control unit to the motor end cover, according to an embodiment of the present disclosure.Detailed Description

[0007] Exemplary embodiments now will be described with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey its scope to those skilled in the art. The terminology used in the detailed description of the particular exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting. In the drawings, like numbers refer to like elements. The term “exemplary embodiment” is meant to be interpreted as being an example embodiment and is not meant to be interpreted as a preferred embodiment.

[0008] The specification may refer to “an”, “one” or “some” embodiment(s) in several locations. This does not necessarily imply that each such reference is to the same embodiment(s), or that the feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments.

[0009] As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless expressly stated otherwise. It will be further understood that the terms “includes”, “comprises”, “including” and / or “comprising” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Conditional language, such as among others, “can” or “may”, unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain embodiments could include, while other embodiments may not include certain features, elements, and / or steps. Thus, such conditional language is not generally intended to imply that features, elements, and / or steps are in any way required for one or more embodiments. It will be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. Furthermore,“connected” or “coupled” as used herein may include wirelessly connected or coupled. As used herein, the term “and / or” includes any and all combinations and arrangements of one or more of the associated listed items.

[0010] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0011] The figures depict a simplified structure only showing some elements and functional entities, all being logical units whose implementation may differ from what is shown. The connections shown are logical connections; the actual physical connections may be different. In addition, all logical units described and depicted in the figures include the software and / or hardware components required for the unit to function. Further, each unit may comprise within itself one or more components, which are implicitly understood. These components may be operatively coupled to each other and be configured to communicate with each other to perform the function of the said unit.

[0012] The embodiments herein disclose a motor assembly (also referred to as an integrated MCU) with active cooling. The motor assembly comprises a coolant path through which a coolant medium can be used to cool electronic components, within the motor assembly, that generate heat. The coolant path is created by a drilling operation in the casing of the motor end cover. Advantages of the embodiments disclosed herein include: (i) eliminating the need for split casing, (ii) eliminating the need for a seal, (iii) reducing the number of parts in the motor assembly, (iv) increasing the operating life of the MCU, (v) eliminating the need of servicing, (vi), eliminating the need of assembly processes due to elimination of parts, and (vii) reducing the overall cost. The embodiments herein are also compact in nature, thereby reducing the complexity in the packaging of the integrated MCU and the motor in a vehicle. The embodiments herein improve the heat derating ofthe integrated MCU, and the single-flow coolant path in the motor end cover reduces the temperature from the motor to the motor control unit.

[0013] FIG. 1A illustrates a view of the top side of an integrated motor control unit (MCU) 100 (also referred to as “motor assembly”) and FIG. IB illustrates a view of a bottom side of the integrated MCU 100, according to an embodiment of the present disclosure. According to FIG. 1A, the integrated MCU 100 has DC terminals 102 and a top cover 104. FIG. IB illustrates a bottom surface of a motor end cover 106 of the integrated MCU 100.

[0014] FIGS. 2A and 2B illustrate an integrated MCU 100 without the motor top cover 104, to show a triangular-shaped single-flow coolant path 108, having an inlet 110 and an outlet 112 disposed on the same side of a housing 150 of the integrated MCU 100. The inlet 110 and the 112 are situated within a motor end cover 106 of the integrated MCU 100 The motor end cover 106 is attached to a side of the housing 150, such that the housing 150 is located at a other side of the motor end cover 106. The coolant path 108 may be carved within the casing of the motor end cover 106 by, for example, a drilling action. FIGS. 2A and 2B also illustrate that there is no limitation with respect to the direction of the flow of a coolant medium across the coolant path 108. In other words, the positions of the inlet 110 and the outlet 112 are interchangeable, thereby allowing the flow of the coolant medium in opposite directions. The coolant medium enters the motor end cover 106 and flows across the single-flow coolant path 108 via the inlet 110. The coolant medium exits the motor end cover 106 via the outlet 112. The coolant medium can be a fluid such as cooling air, water or an ethylene glycol-water mixture. By way of example, rather than limitation, the inlet 110 and the outlet 112 can each have a diameter of 5mm. In FIG. 2A, the arrows along the coolant path 108 indicate the direction of flow of the coolant medium. The MCU 100 also comprises a heat sink 140, as shown in FIG. 2A.

[0015] FIGS. 3A, 3B, and 3C illustrate a top view of the motor end cover 106 with the triangular- shaped single-flow coolant path 108, a top view of the motor end cover 108 with projections 114 along the triangular-shaped single-flow coolant path 108, and a front view of the motor end cover 106, respectively, according to an embodiment of the presentdisclosure. FIG. 3A depicts the coolant path 108 that is drilled into the casing of the motor end cover 106. In FIG. 3B, there are three V-shaped projections 114 that are placed across the triangular- shaped coolant path 108. By way of example, rather than limitation, the shape of the projections 114 can align along with the shape of the coolant path 108. Additionally, the coolant path’s shape is not limited to being triangular- shaped, as shown in FIGS. 5 A and 5B. The cross section of the coolant flow path 108 can be circular.

[0016] FIG. 4 illustrates a view of the motor end cover 106 with a coolant path 108 drilled into the casing of the motor end cover 106, and three V-shaped projections 114 situated along the coolant path 108, according to an embodiment of the present disclosure. Each V- shaped projection 114 comprises a first layer 116 and a second layer 118. The first layer 116 rests on top of the second layer 118. The second layer 118 is covered by a material (e.g., a thermal interface material) 120 that is thermally conductive and electrically insulating. The first layer 116 supports at least one electronic component 126 (as shown in FIG. 6) mounted on the printed circuit board 124 (as inferred from FIG. 10).

[0017] FIG. 5A illustrates a view of the motor end cover 106 with a rectangular-shaped singleflow coolant path 108 drilled into the casing of the motor end cover 106, according to another embodiment of the present disclosure. The coolant medium flows through the inlet 110 of the coolant path 108, and exits from the coolant path 108 from the outlet 112. FIG. 5B illustrates a view of the motor end cover 106 with three V-shaped projections located across the rectangular-shaped coolant path 108. In another embodiment, the shape of the projections 114 can be L-shaped so as to align along with the rectangular shape of the coolant path 108. FIG. 5B also illustrates the fastening point 144 at which the projections 114 are fastened to the motor end cover 106. In another embodiment, the coolant path can be square-shaped. In other embodiments, the at least one projection 114 can be U-shaped or arc-shaped. It is to be noted that the scope of the embodiments herein are not limited to the shape of the coolant path 108 or the projections 114. Additionally, in other embodiments, the projection(s) 114 can be a cast structure along with the motor end cover 106. This too, is to be construed as non-limiting.

[0018] FIG. 6 illustrates a top view of a top side of a motor control unit 122, according to an embodiment of the present disclosure. The motor control unit 122 comprises a printed circuit board 124, at least one electronic component 126, and at least one capacitor 128. The component 126 generates heat when the motor is in operation. Examples of the component can be a power switching device, such as, but not limited to, a MOSFET, an insulated gate bipolar transistor (IGBT), thyristor etc. When the component 126 is in operation, to control the power for driving a motor, they start to generate heat, and as a result, they need to be cooled down. The motor control unit 122 is operatively coupled to the motor.

[0019] FIG. 7 illustrates the contact between at least one electronic component 126 in the printed circuit board 124 and a coolant flow path 108 carrying a coolant medium that enables cooling of the at least one electronic component 126, according to an embodiment of the present disclosure. The printed circuit board 124 comprises a controller 130 that can control the operation of the component 126 to adjust the power directed towards the motor. In other words, the controller 130 is operatively coupled to the electronic component(s) 126. The component 126 heats up when it is in operation, however, due to the thermal contact between the component 126 and the coolant pipe 132 (carrying a coolant medium), the component 126 is cooled down.

[0020] FIG. 8 illustrates a bottom side of the printed circuit board 124 in the motor control unit 122, according to an embodiment of the present disclosure. In FIG. 8, the devices surrounded by the dotted circle are the capacitors 128. On the bottom side of the printed circuit board 124, there are also the DC terminals 102, AC terminals 138, small capacitors 136, and chips 134.

[0021] FIG. 9 illustrates a sectional view of the integrated MCU, according to an embodiment of the present disclosure. FIG. 9 depicts the projection 114, the at least one electronic component 126, and a heat sink 140 integrated with the coolant path 108.

[0022] FIG. 10 illustrates connection of the motor control unit 122 to the motor end cover 106, according to an embodiment of the present disclosure. The motor control unit 122 comprises the printed circuit board 124, the at least one capacitor 128, and at least one electronic component 126 capable of generating heat (not shown in FIG. 10). The at least one electronic component 126 is located on a top side of the printed circuit board 124. FIG. 10 illustrates how the top side of the printed circuit board 124 contacts the motor end cover 106. In other words, the at least one electronic component 126, on the top side of the printed circuit board 124 (shown in FIG. 6), faces the surface of the motor end cover 106, and is supported by the at least one projection 114. The projection(s) 114 on the motor end cover 106 can be arranged such that they support the at least one electronic component 106 on the top side of the printed circuit board 124. The projections 114 may be arranged, on the motor end cover 106, in a path that aligns with the arrangement of the at least two electronic components 126 on the top side of the printed circuit board 124. Alternatively, at least two electronic components 126 can be arranged in a path, on the top side of the printed circuit board 124, that aligns with the arrangement of the projections 114. This can allow for the projection(s) 114 to directly support the at least two electronic components 126.

[0023] As previously stated herein, the projection(s) 114 are arranged across the single-flow coolant path 108. Therefore, when the coolant medium flows through the coolant path 108, owing to the thermal contact between the projection(s) 114 and the at least one electronic component 106, the at least one electronic component 106 is cooled down. The projection(s) 114 is thermally connected to the at least one electronic component 106 to transfer the heat generated by the at least one electronic component 106 to the coolant medium.

[0024] FIG. 10 also illustrates the motor end cover 106 comprising a plurality of phase connectors 146 mounted on the motor end cover 106, and a plurality of bus bars 148 for the phase connector 146, which is located on the bottom side of the printed circuit board 124 of the motor control unit 122. The bottom side of the printed circuit board 124 also comprises fasteners 142 for fastening the motor control unit 122 to the motor end cover106, small capacitors 136, and chips 134. The bottom side of the printed circuit board 124 may then be covered by a motor top cover 104, as shown in FIG. 1A. The casing of the motor end cover also helps with the dissipation of heat generated by the motor.

[0025] Although the figures highlight how the coolant medium cools the plurality of electronic components 126 in the motor control unit 122, they also cool the housing located at the other side of the motor end cover 106.

[0026] Although not shown in the figures, the coolant medium (e.g., air, water, or ethylene glycol-water mixture) can be dispensed by a fluid pump when the average temperature of at least one electronic component 106, measured by a temperature sensor, exceeds a threshold. A control unit, on obtaining the temperature data from the temperature sensor, can send a signal to the fluid pump to dispense the coolant medium. When the average temperature of the at least one electronic component falls below a second threshold, the control unit can transmit a signal to the fluid pump to discontinue the dispensing of the coolant medium. In one embodiment, the temperature threshold for dispensing the coolant medium can be 60°C, and the temperature threshold for discontinuing the dispensing of the coolant medium can be 40°C. In some embodiments, the coolant medium, after exiting the outlet 112, can be directed to a heat exchanger (e.g., a radiator) to exchange heat prior to the coolant medium being circulated again.

[0027] The control unit can be a hardware or a device that includes, without limitation, a processor, a memory, a communications interface, and programmable logic or software. A processor can be a single processor or a plurality of processors. The processor can be a general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.

[0028] In the drawings and specification, there have been disclosed exemplary embodiments of the invention. Although specific terms are employed, they are used in a generic and descriptive sense only and not for purposes of limitation. It will be apparent to those having ordinary skill in this art that various modifications and variations may be made to the embodiments disclosed herein, consistent with the present invention, without departing from the spirit and scope of the present invention. Other embodiments consistent with the present invention will become apparent from consideration of the specification and the practice of the description disclosed herein.

[0029] The following table illustrates the association between a reference numeral and a feature of an embodiment of the present disclosure.

Claims

We claim:

1. A motor assembly (100), comprising: a housing (150); a motor control unit (122), operatively coupled to a motor, comprising: a printed circuit board (PCB) (124); at least one electronic component (126), that generates heat, mounted on a top side of the PCB; and a controller (130) mounted on the top side of the PCB and operatively coupled to the at least one electronic component; and a motor end cover (106), attached to a side of the housing, wherein the motor end cover comprises: a single-flow coolant path (108) that is directly drilled into a casing of the motor end cover; at least one projection (114) located on a top side of the motor end cover and arranged along the single-flow coolant path; an inlet (110) through which a coolant medium enters the motor end cover and flows along the single-flow coolant path; and an outlet (112) through which the coolant medium exits the motor end cover from the single-flow coolant path, wherein the top side of the PCB is directly placed on the motor end cover such that the at least one projection supports the at least one electronic component located on the top side of the PCB.

2. The motor assembly as claimed in claim 1, comprising a heat sink (140) integrated with the single-flow coolant path, wherein the at least one projection is thermally connected to the at least one electronic component to transfer the heat generated by the at least one electronic component to the coolant medium.

3. The motor assembly as claimed in claim 1, wherein the single-flow coolant path is at least one of: triangular-shaped, rectangular- shaped, or square-shaped.

4. The motor assembly as claimed in claim 1, wherein the at least one projection is at least one of: V-shaped, U-shaped, L-shaped, and arc-shaped.

5. The motor assembly as claimed in claim 1, wherein the cross section of the coolant flow path is circular.

6. The motor assembly as claimed in claim 1, wherein the at least one projection is shaped in a manner that aligns along with the shape of the single-flow coolant path.

7. The motor assembly as claimed in claim 6, wherein at least two electronic components are arranged in a path, that is shaped to align with the at least one projection’s shape, on the top side of the PCB, such that the at least one projection supports the at least two electronic components.

8. The motor assembly as claimed in claim 1, wherein the at least one projection is: fastened to the motor end cover; or a cast structure along with the end cover.

9. The motor assembly as claimed in claim 1, comprising: a plurality of phase connectors (146) mounted on the motor end cover; and a plurality of bus bars (148), for the plurality of phase connectors, mounted on the bottom side of the PCB.

10. The motor assembly as claimed in claim 1, wherein the surface of the at least one projection comprises a first layer (116) and a second layer (118), the first layer resting on the second layer, wherein the first layer supports the at least one electronic component, and wherein the second layer is covered by a material (120) that is electrically insulating and thermally conductive.

11. The motor assembly as claimed in claim 1 , wherein the at least one electronic component is at least:a MOSFET; an insulated gate bipolar transistor; and a thyristor.

12. The motor assembly as claimed in claim 1, wherein the coolant medium is a fluid including at least one of: cooling air; water; and an ethylene glycol-water mixture.

13. The motor assembly as claimed in claim 12, wherein the coolant medium is dispensed by a fluid pump when the average temperature of the at least one electronic component, measured by a temperature sensor, exceeds a threshold.

14. The motor assembly as claimed in claim 13, wherein the fluid pump dispenses the coolant medium when the average temperature of the at least one electronic component exceeds 60°C.

15. The motor assembly as claimed in claim 14, wherein the fluid pump discontinues the dispensing of the coolant medium when the average temperature of the at least electronic component is below 40°C.

16. The motor assembly as claimed in claim 1, wherein the inlet and the outlet each have a diameter of 5 mm.

17. The motor assembly as claimed in claim 1, wherein the heat generated by the motor is dissipated by the casing of the motor end cover.

18. The motor assembly as claimed in claim 1, wherein the coolant medium cools the motor housing located at a other side of the motor end cover.

19. The motor assembly as claimed in claim 1, wherein the outlet is connected to a heat exchanger through which the coolant medium, after exiting the outlet, is cooled down.

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