Electric drive unit with heat exchanger

Abstract

An electric drive unit includes an electric motor and a housing accommodating the electric motor. The housing includes a heat exchange wall portion including an inner surface defining a fluid jacket cavity for conveying a first fluid and an outer surface opposite the inner surface and defining a fluid chamber for conveying a second fluid. Heat is transferred between the first fluid and the second fluid through the heat exchange wall portion.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 63 / 428,673 filed on November 29, 2022, U.S. Provisional Application No. 63 / 346,176 filed on May 26, 2022, and U.S. Non-Provisional Application No. 18 / 177,236 filed on March 2, 2023, the entire contents of the above applications are incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to electric drive units. More specifically, the present disclosure relates to heat exchangers for electric drive units. Background Art

[0004] Typically, electric axles are designed to fit into minimal vehicle installation space. Heat dissipation in electric axles is increasingly important due to the power density achieved by electric axles. For example, electric axles using asynchronous induction motors typically require active rotor cooling to function. Therefore, it is desirable to provide a way to achieve performance goals for cooling without adding significant cost, components, and complexity to the assembly. Summary of the invention

[0005] According to a first aspect of the present disclosure, an electric drive unit includes an electric motor and a housing for accommodating the electric motor. The housing includes a heat exchange wall portion, the heat exchange wall portion including an inner surface and an outer surface, the inner surface defining a fluid jacket cavity for conveying a first fluid, the outer surface being opposite to the inner surface and defining a fluid chamber for conveying a second fluid. Heat is transferred between the first fluid and the second fluid through the heat exchange wall portion.

[0006] Implementations of the first aspect of the present disclosure may include any one or combination of the following features:

[0007] - the inner surface of the heat exchange wall portion is axially and circumferentially aligned with the outer surface of the heat exchange wall portion;

[0008] - the electric motor comprises a rotor and a stator positioned radially outside the rotor, and wherein the stator is axially aligned with a heat exchange wall portion of the housing;

[0009] - the fluid jacket cavity is defined by the inner surface of the heat exchange wall portion and the stator carrier, wherein a portion of the stator carrier is axially aligned with the stator and is located radially outside the stator;

[0010] - the first fluid comprises water and the second fluid is oil;

[0011] - heat is transferred from the second fluid to the first fluid through the heat exchange wall section;

[0012] - the outer surface of the heat exchange wall portion is formed with a base and a plurality of projections extending radially outwardly from the base;

[0013] - a cover is mounted to the housing and arranged radially outwardly of the heat exchanging wall portion such that an outer surface of the heat exchanging wall portion and the cover cooperate to define a fluid chamber;

[0014] - the cover comprises a plurality of projections extending radially inwardly towards the outer surface of the heat exchange wall portion of the housing;

[0015] - the plurality of protrusions of the cover are aligned with the plurality of protrusions of the outer surface of the heat exchange wall portion so that the distal ends of the plurality of protrusions of the cover face the distal ends of the plurality of protrusions of the outer surface of the heat exchange wall portion;

[0016] - the outer surface of the heat exchange wall portion is further formed with baffles which extend radially outwards from the base portion than the plurality of protrusions of the outer surface of the heat exchange wall portion extend radially outwards from the base portion;

[0017] - the cover comprises baffles extending radially inwardly along the baffles formed by the outer surface of the heat exchange wall portion; and

[0018] -A plurality of protrusions extending radially outward from the base include: a first protrusion having a certain height, width and length, the height being the distance from the base to the distal end of the first protrusion extending outward, and the length being greater than the width of the first protrusion, so that the first protrusion is elongated along the length direction of the first protrusion; a second protrusion having a certain height, width and length, the height being the distance from the base to the distal end of the second protrusion extending outward, and the length being greater than the width of the second protrusion, so that the second protrusion is elongated along the length direction of the second protrusion; wherein the first protrusion and the second protrusion are oriented so that the angular difference between the length direction of the first protrusion and the length direction of the second protrusion is greater than the angular difference between the height direction of the first protrusion and the height direction of the second protrusion.

[0019] According to a second aspect of the present disclosure, an electric drive unit includes a body having a surface defining a fluid chamber. The surface is formed with a base and a plurality of protrusions extending outward from the base in the fluid chamber. The plurality of protrusions include a first protrusion having a certain height, width and length, the height being the distance from the first protrusion extending outward from the base to the distal end of the first protrusion, the length being greater than the width of the first protrusion, so that the first protrusion is elongated along the length direction of the first protrusion. The plurality of protrusions also include a second protrusion having a certain height, width and length, the height being the distance from the second protrusion extending outward from the base to the distal end of the second protrusion, the length being greater than the width of the second protrusion, so that the second protrusion is elongated along the length direction of the second protrusion. The first protrusion and the second protrusion are oriented so that the angular difference between the length direction of the first protrusion and the length direction of the second protrusion is greater than the angular difference between the height direction of the first protrusion and the height direction of the second protrusion.

[0020] The embodiments of the second aspect of the present disclosure may include any one or combination of the following features:

[0021] - the body is a housing housing the electric motor, and said surface is an outer surface of a heat exchanging wall portion of the housing;

[0022] - the heat exchanging wall portion comprises an inner surface opposite the outer surface, wherein the inner surface defines a fluid jacket cavity;

[0023] - the heat exchange wall portion is configured to transfer heat from a second fluid conveyed within the fluid chamber to a first fluid conveyed within the fluid jacket cavity;

[0024] - the body is a cover coupled to a housing housing the electric motor, wherein the cover and the housing define a fluid chamber; and

[0025] -The multiple protrusions also include a third protrusion, which has a certain height, width and length, the height is the distance the third protrusion extends outward from the base to the distal end of the third protrusion, and the length is greater than the width of the third protrusion, so that the third protrusion extends along the length direction of the third protrusion, wherein the third protrusion is oriented so that the angle difference between the length direction of the first protrusion and the length direction of the third protrusion is greater than the angle difference between the height direction of the first protrusion and the height direction of the third protrusion, the angle difference between the length direction of the second protrusion and the length direction of the third protrusion is greater than the angle difference between the height direction of the second protrusion and the height direction of the third protrusion, and the angle difference between the length direction of the first protrusion and the length direction of the third protrusion is greater than the angle difference between the length direction of the second protrusion and the height direction of the third protrusion, and the angle difference between the length direction of the first protrusion and the length direction of the third protrusion is greater than the angle difference between the length direction of the second protrusion and the length direction of the third protrusion.

[0026] According to a third aspect of the present invention, an electric drive unit comprises: an electric motor; a housing that accommodates the electric motor and includes an outer surface formed with a base and a plurality of protrusions extending radially outward from the base; and a cover that is coupled to the housing and has a plurality of protrusions aligned with the plurality of protrusions of the outer surface of the housing. The outer surface of the housing and the cover cooperate to define a fluid chamber for conveying a fluid.

[0027] Those skilled in the art will further understand and appreciate these and other features, advantages, and objects of the present disclosure by referring to the appended description, claims, and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In the attached picture:

[0029] Figure 1 is a top perspective view of an electric drive unit including a housing;

[0030] Figure 2 is a side view of the electric drive unit;

[0031] Figure 3 yes Figure 2 a cross-sectional view of an electric drive unit taken along line III-III, illustrating a heat exchanger of the electric drive unit and a heat exchange wall portion of the housing;

[0032] Figure 4 yes Figure 3 An enlarged view of region IV in FIG. 1 , which illustrates the heat exchanger of the electric drive unit and the heat exchange wall portion of the housing;

[0033] Figure 5 is a perspective view of an electric drive unit including a cover coupled to a housing of the electric drive unit;

[0034] Figure 6 yes Figure 5 a cross-sectional view of a portion of an electric drive unit illustrating a cover and a heat exchange wall portion of the housing defining a fluid chamber;

[0035] Figure 7 is an enlarged perspective view of a portion of a body of an electric drive unit illustrating a plurality of protrusions extending outwardly from a base of a surface of the body;

[0036] Figure 8 is a front view of a portion of a housing of an electric drive unit including a plurality of protrusions and a plurality of baffles;

[0037] Fig. 9 is a front view of a cover of an electric drive unit, the cover including a plurality of protrusions and a plurality of baffles;

[0038] Fig.10 is a front view of an embodiment of a portion of a housing of an electric drive unit including a plurality of protrusions;

[0039] Fig.11 is a front view of an embodiment of a portion of a housing of an electric drive unit including a plurality of protrusions;

[0040] Fig.12 is a front view of an embodiment of a portion of a housing of an electric drive unit including a plurality of protrusions;

[0041] Fig.13 is a front view of an embodiment of a portion of a housing of an electric drive unit including a plurality of protrusions; and

[0042] Fig.14 is a front view of the electric drive unit, which illustrates the flow path of the fluid within the electric drive unit. DETAILED DESCRIPTION

[0043] Additional features and advantages of the disclosure will be set forth in the following detailed description and will become apparent to those skilled in the art from the description or learned by practicing the disclosure as described in the following description and claims and the accompanying drawings.

[0044] As used herein, the term "and / or," when used in a list of two or more items, means that any one of the listed items may be taken alone, or any combination of two or more of the listed items may be taken. For example, if a composition is described as containing components A, B, and / or C, the composition may contain only A; only B; only C; a combination of A and B; a combination of A and C; a combination of B and C; or a combination of A, B, and C.

[0045] In this document, relational terms such as "first" and "second", "top" and "bottom", etc. are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.

[0046] For purposes of this disclosure, the term "coupled" (in all its forms: coupled, coupled with, coupled, etc.) generally means the joining of two components (electrical or mechanical) to one another, directly or indirectly. Such joining may be stationary in nature or movable in nature. Such joining may be achieved through the two components (electrical or mechanical) and / or any additional intermediate members. Such joining may include integrally forming the components to one another as a single entity (i.e., integrally coupled) or may refer to the joining of two components. Unless otherwise specified, such joining may be permanent in nature or may be removable or releasable in nature.

[0047] As used herein, the terms "substantially," "substantially," and variations thereof are intended to mean that the feature being described is equal to or approximately equal to a value or description. For example, a "substantially planar" surface is intended to mean a planar or approximately planar surface. Additionally, "substantially" is intended to mean that two values ​​are equal or approximately equal. In some embodiments, "substantially" can mean that values ​​are within about 10% of each other, such as within about 5% of each other, or within about 2% of each other.

[0048] As used herein, the terms "the," "a," or "an" mean "at least one," and should not be limited to "only one," unless clearly indicated to the contrary. Thus, for example, reference to "a component" includes embodiments having two or more such components, unless the context clearly indicates otherwise.

[0049] As used herein, the term "axial" and its derivatives such as "axially" should be understood to refer to a direction along an axis of a rotor shaft that is configured to rotate about the axis during operation of the apparatus described herein. In addition, the term "radial" and its derivatives such as "radially" should be understood with respect to the aforementioned axis of the rotor shaft. For example, "radially outside" means farther from the axis, while "radially inside" means closer to the axis. The term "circumferential" and its derivatives such as "circumferentially" should be understood with respect to the aforementioned axis of the rotor shaft.

[0050] Embodiments of the present disclosure are described herein. It should be understood that the same reference numerals appearing in different figures identify the same or functionally similar structural elements. In addition, it will be understood that the disclosed embodiments are examples only, and other embodiments may take various forms and alternative forms. The drawings are not necessarily drawn to scale; some features may be enlarged or minimized to show the details of a particular component. Therefore, the specific structural and functional details disclosed herein should not be interpreted as being restrictive, but only as a representative basis for teaching those skilled in the art to utilize the embodiments in various ways. As will be understood by those of ordinary skill in the art, the various features illustrated and described with reference to any of the drawings in the drawings may be combined with the features illustrated in one or more other drawings to produce an embodiment that is not explicitly illustrated or described. The combination of the illustrated features provides a representative embodiment for a typical application. However, for a particular application or implementation, various combinations and modifications of features consistent with the teachings of the present disclosure may be required.

[0051] The terms used herein are only for the purpose of describing specific aspects and are not intended to limit the scope of the present disclosure. Unless otherwise specified, all technical terms and scientific terms used herein have the same meaning as those generally understood by those of ordinary skill in the art to which the present disclosure belongs. Although any method, device or material similar or equivalent to those described herein can be used in the practice or testing of the present disclosure, the following example methods, devices and materials will now be described.

[0052] Embodiments according to the present disclosure provide active rotor cooling without adding significant cost to components, such as typical stacked plate heat exchangers and oil pumps. The heat exchanger is incorporated into existing components and also utilizes the existing electric motor stator fluid jacket as a direct oil-to-water heat exchanger without adding a water circuit, which is particularly important in this case for auxiliary drive units that are only functional at intermittent times in the vehicle.

[0053] Thus, the stator fluid jacket is used to absorb heat not only from the stator laminations, but also from the oil for rotor cooling. Heat exchange from the oil to the water is facilitated by forming a fluid chamber (e.g., an oil chamber) integral with the center housing casting, which is arranged around the wall of the stator fluid jacket into which the oil is delivered. The oil exchanges heat with the fluid within the fluid jacket cavity, and the cooled oil is fed to the rotor shaft.

[0054] Heat extraction from a heat exchanger depends on the oil flow rate present, the magnitude of the flow rate, the fluid dynamics, and the time the oil resides in the heat extraction zone. The geometry of the heat exchanger has an effect on the pressure and, therefore, the oil flow rate. Since the electric drive unit does not use an oil pump, the flow rate decreases as the pressure decreases. The geometry of the heat exchanger also has an effect on the fluid dynamics. In general, the more turbulent the flow of the fluid, the greater the heat transfer and pressure reduction. Heat transfer also depends on the wetted surface area of ​​the heat exchanger. A larger wetted surface area produces better heat transfer. The geometry of the heat exchanger also has an effect on the time the oil resides in the heat extraction zone. The more restrictive the heat exchanger, the longer the oil resides in the heat extraction zone and the pressure decreases. Heat exchangers extract heat by conduction and convection. The material as well as the surface area and thickness have a significant effect on the heat transfer. High oil flow rates allow for better heat extraction by convection without significantly increasing the temperature of the oil returning to the gearbox. Low oil flow rates increase the time the oil resides inside the heat extraction zone, which increases heat extraction by conduction. No oil flow rate will cause the system to overheat.

[0055] According to embodiments disclosed herein, a heat exchanger assembly is provided that causes relatively low fluid pressure reduction (and therefore less restriction to oil flow rate), greater turbulence (without substantially reducing pressure), greater surface area (through protrusions and / or baffles), and longer residence time of the oil in the heat extraction zone (without substantially reducing pressure). In this way, embodiments disclosed herein provide a heat exchanger assembly that achieves good thermal performance.

[0056] Now refer to Figures 1 to 4 , an electric drive unit 10 for a vehicle having a heat exchanger 12 is provided, wherein the electric drive unit 10 is designed as an electric axle ("e-axle"). The electric drive unit 10 has a housing 14. The housing 14 can be functionally divided into a motor housing area or a central housing area 16 and a gear housing area or a gearbox housing area 18. In some embodiments, the housing 14 can be designed as a die-cast aluminum housing and can be formed from multiple parts. For example, the gearbox 20 can include a planetary gear set, a differential, and a reservoir 22. The heat exchanger 12 can be combined with or integrated into the housing 14. That is, an existing planned casting process for the housing 14 can be used to form at least a portion of the heat exchanger 12. In some embodiments, the heat exchanger 12 can be combined with or integrated into the central housing area 16. The housing 14 may include a heat exchange wall portion 24, which forms a portion of the heat exchanger 12, as further described herein. In some embodiments, the heat exchanger 12 can be located on the bottom of the electric drive unit 10, such as Figure 3In some embodiments, the heat exchanger 12 may be located in another location, such as on top of the electric drive unit 10 .

[0057] Now refer to Figures 1 to 6 The housing 14 includes an inner surface 26 and an outer surface 28 opposite to the inner surface 26. Figure 3 As shown in FIG. 1 , the outer surface 28 of the central housing region 16 of the housing 14 is radially outward of the inner surface 26 of the central housing region 16 . The fluid chamber 30 of the heat exchanger 12 may be defined by the outer surface 28 of a portion of the housing 14 , such as the outer surface 28 of a portion of the central housing region 16 of the housing 14 . Figure 3 and Figure 4 As shown, the fluid chamber 30 is defined by the outer surface 28 of the heat exchange wall portion 24 of the housing 14. In some embodiments, a cover 32 is mounted to the housing 14. For example, in Figure 5 and Figure 6 In the illustrated embodiment, the cover 32 is mounted to the outer surface 28 of the central housing region 16 of the housing 14 and is arranged radially outwardly of the heat exchange wall portion 24 of the housing 14. Figure 5 In the illustrated embodiment, the cover 32 is mounted to the outer surface 28 of the central housing region 16 of the housing 14. The outer surface 28 of the heat exchange wall portion 24 of the housing 14 and the cover 32 can cooperate to define a fluid chamber 30, such as Figure 6 Fluid chamber 30 is configured to convey fluid during operation of electric drive unit 10 , as further described herein.

[0058] Still refer to Figures 1 to 6 The electric drive unit 10 includes an electric motor 34 having a stator 36, a rotor 38, a stator carrier 40, and a rotor shaft 42. The stator 36 is positioned radially outward of the rotor 38. The housing 14 accommodates the electric motor 34, such as Figure 3 As shown. The stator carrier 40 and a portion of the housing 14 form and define a fluid jacket 44. In various embodiments, the fluid jacket 44 is formed and defined by the stator carrier 40 and the inner surface 26 of the central housing region 16 of the housing 14. Figure 3 and Figure 4 As shown, the inner surface 26 of the heat exchange wall portion 24 of the housing 14 forms a portion of a fluid jacket 44. The fluid jacket 44 defines a fluid jacket cavity 46 configured to convey a fluid, as further described herein. Figure 3 In the illustrated embodiment, the inner surface 26 of a portion of the housing 14 , including the inner surface 26 of the heat exchange wall portion 24 of the housing 14 , and the stator carrier 40 define a fluid jacket cavity 46 .

[0059] The fluid jacket cavity 46 can be filled with a first fluid 48, such as, for example, a water-glycol mixture, for cooling the stator 36. A second fluid 50, such as oil, is disposed within the fluid chamber 30 of the heat exchanger 12, the fluid chamber being defined by the outer surface 28 of the heat exchange wall portion 24 of the housing 14. Heat is transferred between the first fluid 48 and the second fluid 50 through the heat exchange wall portion 24 of the housing 14. In operation of an exemplary embodiment of the electric drive unit 10, wherein the first fluid 48 comprises water (e.g., a water-glycol mixture) and the second fluid 50 is oil, the heat exchanger 12 functions by transferring heat from the second fluid 50 to the first fluid 48 through the heat exchange wall portion 24. In such an embodiment, the fluid within the fluid chamber 30 is cooled. This arrangement can advantageously allow heat exchange between the first fluid 48 and the second fluid 50 without increasing fluid pressure losses or adding additional fluid circuits. It is contemplated that a variety of different types of fluids may be used as the first fluid 48 within the fluid jacket cavity 46 and the second fluid 50 within the fluid chamber 30. As Figure 3 As illustrated, in various embodiments, the inner surface 26 of the heat exchange wall portion 24 is axially and circumferentially aligned with the outer surface 28 of the heat exchange wall portion 24, the stator 36 is axially aligned with the heat exchange wall portion 24 of the housing 14, and a portion of the stator carrier 40 is axially aligned with the stator 36 and located radially outside the stator.

[0060] Now refer to Figures 4 to 13 , the electric drive unit 10 may include a body 52. ​​In some embodiments, the electric drive unit 10 includes a plurality of bodies 52. The body 52 includes a surface 54 that defines a fluid chamber 30. In some embodiments, the body 52 is a housing 14 that accommodates an electric motor 34, and the surface that defines the fluid chamber 30 is an outer surface 28 of a heat exchange wall portion 24 of the housing 14. In some embodiments, the body 52 is a cover 32 coupled to the housing 14, and the cover 32 and the housing 14 define the fluid chamber 30. The surface 54 of the body 52 that defines the fluid chamber 30 may include a protrusion 56 and / or a baffle 58. In various embodiments, the surface 54 of the body 52 that defines the fluid chamber 30 includes a plurality of protrusions 56 and / or a plurality of baffles 58.

[0061] Now refer to Figure 3 , Figure 4 , Figures 6 to 8 as well as Figures 10 to 13 , a body 52 is illustrated in the form of a heat exchange wall portion 24 of a housing 14. In various embodiments, an outer surface 28 of the heat exchange wall portion 24 of the housing 14 defining the fluid chamber 30 is formed with a base 60 and a plurality of protrusions 56 extending outwardly from the base 60. Figure 6As shown, the plurality of projections 56 extend outwardly from a base 60 of the outer surface 28 of the heat exchange wall portion 24 to distal ends 62 of the plurality of projections 56. In various embodiments, the plurality of projections 56 extend radially outwardly from the base 60 of the outer surface 28 of the heat exchange wall portion 24, such as Figure 3 , Figure 4 and Figure 6 As shown in the figure exemplarily.

[0062] A given protrusion 56 of the plurality of protrusions 56 extending radially outward from a base 60 of the outer surface 28 of the heat exchange wall portion 24 may have a certain height, width, and length, wherein the height is the distance the protrusion 56 extends outward from the base 60 to the distal end 62 of the protrusion 56. The length is greater than the width of the protrusion 56, such that the protrusion 56 is elongated along the length direction of the protrusion 56, such as Figure 7 In an exemplary embodiment, the height of the protrusion 56 or fin is about 8 mm, the width of the protrusion 56 is about 3 mm, and the length of the protrusion 56 is about 6 mm. In various embodiments, each of the plurality of protrusions 56 may have substantially the same dimensions, such as Figure 7 As shown. Figure 7 The height, width, and length of a single protrusion 56 are labeled “H,” “W,” and “L,” respectively.

[0063] Now refer to Figure 7 The projections 56 formed by the outer surface 28 of the heat exchange wall portion 24 of the housing 14 can be oriented relative to each other so that the length directions of the projections 56 vary relative to each other. The inconsistency of the length directions of the projections 56 can advantageously affect the flow of the fluid within the fluid chamber 30. Figure 7 In the exemplary embodiment illustrated in , the plurality of protrusions 56 extending radially outward from the base 60 include a first protrusion 64 and a second protrusion 66. The first protrusion 64 has a certain height, width, and length, the height being the distance from the first protrusion 64 extending outward from the base 60 to the distal end 62 of the first protrusion 64, and the length being greater than the width of the first protrusion 64, so that the first protrusion 64 is elongated along the length direction of the first protrusion 64. The second protrusion 66 has a certain height, width, and length, the height being the distance from the second protrusion 66 extending outward from the base 60 to the distal end 62 of the second protrusion 66, and the length being greater than the width of the second protrusion 66, so that the second protrusion 66 is elongated along the length direction of the second protrusion 66. As shown in FIG. Figure 7 As illustrated, the first and second protrusions 64 , 66 are oriented such that the angular difference between the length direction of the first and second protrusions 64 , 66 is greater than the angular difference between the height direction of the first and second protrusions 64 , 66 .

[0064] exist Figure 7 In the embodiment shown in the figure, the plurality of protrusions 56 extending radially outward from the base 60 further include a third protrusion 68. The third protrusion 68 has a certain height, width and length, the height being the distance from the third protrusion 68 extending outward from the base 60 to the distal end 62 of the third protrusion 68, and the length being greater than the width of the third protrusion 68, so that the third protrusion 68 is elongated along the length direction of the third protrusion 68. Figure 7 As illustrated, the third protrusion 68 is oriented such that the angular difference between the length direction of the first protrusion 64 and the length direction of the third protrusion 68 is greater than the angular difference between the height direction of the first protrusion 64 and the height direction of the third protrusion 68, and the angular difference between the length direction of the second protrusion 66 and the length direction of the third protrusion 68 is greater than the angular difference between the height direction of the second protrusion 66 and the height direction of the third protrusion 68. In addition, the angular difference between the length direction of the first protrusion 64 and the length direction of the third protrusion 68 is greater than the angular difference between the length direction of the second protrusion 66 and the length direction of the third protrusion 68.

[0065] Now refer to Figure 6 , Figure 8 as well as Figures 10 to 13 In various embodiments, the outer surface 28 of the heat exchange wall portion 24 of the housing 14 that defines the fluid chamber 30 forms one or more baffles 58 that extend radially outward from the base 60. The one or more baffles 58 extend outward from the base 60 farther than the plurality of protrusions 56 extend outward from the base 60, such as Figure 6 As shown in the figure. Figure 8 In the embodiment illustrated in FIG. 8 , a plurality of baffles 58 extend radially outward from a base 60 .

[0066] Now refer to Figures 6 to 8 and Figures 10 to 13 The presence of one or more baffles 58 and / or the angular difference between the length directions of the protrusions 56 can advantageously affect the rate and direction of flow of the fluid within the fluid chamber 30. Figure 8 In the embodiment illustrated in FIG. 1 , the fluid is configured to enter the fluid chamber 30 near the upper right corner of the outer surface 28 of the heat exchange wall portion 24, and to leave the fluid chamber 30 near the upper left corner of the outer surface 28 of the heat exchange wall portion 24 (from Figure 8The baffle 58 defines a serpentine flow path 70 along which the fluid is directed when entering the fluid chamber 30. The plurality of protrusions 56 are disposed within the serpentine flow path 70 and are variably oriented with respect to the angles of the lengthwise directions of the plurality of protrusions. The angle differences between the lengthwise directions of the protrusions 56 may generate turbulence and cause the fluid to flow back and forth in different directions within the wider serpentine flow path 70.

[0067] exist Figures 10 to 13 An alternative baffle and projection arrangement is illustrated in . In the illustrated embodiment, the baffle 58 defines a generally U-shaped flow path 72 for fluid flow through the fluid chamber 30 . Figures 10 to 13 The lengthwise direction of the projection 56 of each of the illustrated embodiments is configured to affect the flow of fluid through the fluid chamber 30 by causing the fluid to flow along a generally U-shaped flow path 72 ( Fig.10 ) flows in the U-shaped direction; preventing the fluid from flowing along the roughly U-shaped flow path 72 ( Fig.11 ) flows in the U-shaped direction; or the fluid flows along the substantially U-shaped flow path 72 to a greater extent ( Fig.12 ) or to a lesser extent ( Fig.13 ) flows in a winding manner.

[0068] The protrusion 56 formed by the outer surface 28 of the heat exchange wall portion 24 of the housing 14 can additionally increase the area of ​​the outer surface 28 in contact with the fluid flowing in the fluid chamber 30, which can improve heat transfer from the fluid to the heat exchange wall portion 24. The housing 14 and the protrusion 56 can be integrally formed by, for example, die casting without machining.

[0069] Now refer to Figure 6 and Fig. 9 The body 52 in the form of the cover 32 includes a plurality of projections 56 extending radially inwardly toward the outer surface 28 of the heat exchange wall portion 24 of the housing 14. Figure 8 As illustrated, the plurality of protrusions 56 extend to the distal ends 62 of the plurality of protrusions 56 of the cover 32. A given protrusion 56 of the plurality of protrusions 56 extending radially inwardly toward the heat exchange wall portion 24 may have a certain height, width, and length, the height being the distance the protrusion 56 extends to the distal end 62 of the protrusion 56, the length being greater than the width of the protrusion 56, such that the protrusion 56 of the cover 32 is elongated in the length direction of the protrusion 56.

[0070] In some embodiments, the projections 56 of the cover 32 are oriented relative to each other such that the length directions of the projections 56 vary relative to each other to affect the flow of the fluid within the fluid chamber 30. For example, in Figure 6In the embodiment shown in the figure, the plurality of protrusions 56 of the cover 32 include a first protrusion 64 and a second protrusion 66. The first protrusion 64 has a certain height, width and length, the height being the distance from the first protrusion 64 to the distal end 62 of the first protrusion 64, and the length being greater than the width of the first protrusion 64, so that the first protrusion 64 is elongated along the length direction of the first protrusion 64. The second protrusion 66 has a certain height, width and length, the height being the distance from the second protrusion 66 to the distal end 62 of the second protrusion 66, and the length being greater than the width of the second protrusion 66, so that the second protrusion 66 is elongated along the length direction of the second protrusion 66. As shown in FIG. Figure 6 As illustrated, the first protrusion 64 and the second protrusion 66 of the cover 32 are oriented such that the angular difference between the length direction of the first protrusion 64 and the length direction of the second protrusion 66 is greater than the angular difference between the height direction of the first protrusion 64 and the height direction of the second protrusion 66. The angular difference between the length directions of the protrusions 56 of the cover 32 can advantageously affect the rate and direction of flow of the fluid within the fluid chamber 30.

[0071] Now refer to Figure 5 , Figure 6 and Fig. 9 In various embodiments, the cover 32 includes one or more baffles 58 extending radially inward. Compared to the radial inward extension of the plurality of protrusions 56 of the cover 32, the one or more baffles 58 may extend radially inward further, such as Figure 6 In some embodiments, the cover 32 includes a plurality of baffles 58 extending radially inwardly, such as Figure 6 In some embodiments, one or more baffles 58 of the cover 32 extend radially inwardly along one or more baffles 58 formed by the heat exchange wall portion 24, so that one or more baffles 58 of the cover 32 and one or more baffles 58 of the heat exchange wall portion 24 radially overlap, as shown in FIG. Figure 6 In the illustrated embodiment, the housing 14 includes one baffle 58 and the cover 32 includes two baffles 58. The baffle 58 of the housing 14 is axially positioned between the two baffles 58 of the cover 32. In general, the baffles 58 of the housing 14 and the baffles of the cover 32 can act as a labyrinth to impede the flow of the fluid within the fluid chamber 30 so that the fluid is guided along the serpentine flow path 70. Figure 5 As illustrated, the cover 32 may also include ribs 74 to facilitate heat transfer via air convection and conduction.

[0072] Now refer to Figure 6 , Figure 8 and Fig. 9In some embodiments, where the fluid chamber 30 is defined by the outer surface 28 of the heat exchange wall portion 24 and the cover 32, the plurality of protrusions 56 of the cover 32 may be aligned with the plurality of protrusions 56 of the outer surface 28 of the heat exchange wall portion 24. For example, Figure 6 As illustrated, the plurality of protrusions 56 of the cover 32 are aligned with the plurality of protrusions 56 of the outer surface 28 of the heat exchange wall portion 24 such that the distal ends 62 of the plurality of protrusions 56 of the cover 32 face the distal ends 62 of the plurality of protrusions 56 of the outer surface 28 of the heat exchange wall portion 24. In the illustrated embodiment, the distal ends 62 of the plurality of protrusions 56 of the cover 32 are in a spaced relationship with the corresponding aligned plurality of protrusions 56 of the outer surface 28 of the heat exchange wall portion 24. In addition, each pair of aligned protrusions 56 has substantially parallel length directions, such as Figure 6 As shown. Fig. 9 The cover 32 shown in FIG. Figure 8 The embodiment of the housing 14 shown in FIG. 1 cooperates to form a fluid chamber 30. Figure 8 and Fig. 9 As shown, the length direction of each protrusion 56 of the cover 32 is configured to be parallel to the length direction of each corresponding aligned protrusion 56 of the outer surface 28 of the heat exchange wall portion 24 of the housing 14 .

[0073] In operation of the exemplary embodiment of the electric drive unit 10, the gearbox 20 collects oil from the gearbox sump 22 and distributes the oil into the fluid chamber 30 (by splashing from rotating components of the gearbox), as shown in FIG. Fig.14 The baffles 58 and projections 56 of the cover 32 and the baffles and projections of the heat exchange wall portion 24 of the housing 14 guide and slow the flow of oil within the fluid chamber 30. This allows heat to be adequately transferred from the relatively hot oil through the heat exchange wall portion 24 of the housing 14 to the relatively cool water-glycol mixture within the fluid jacket cavity 46 defined by the inner surface 26 of the heat exchange wall portion 24. The cooled oil is then delivered to the rotor shaft 42 to provide active rotor cooling.

[0074] Although exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms covered by the claims. The words used in the specification are descriptive rather than restrictive, and it should be understood that various modifications can be made without departing from the spirit and scope of the present disclosure. As previously described, the features of various embodiments can be combined to form other embodiments of the present disclosure that may not be explicitly described or illustrated. Although various embodiments may have been described as providing advantages or being superior to other embodiments or prior art implementations in terms of one or more desired characteristics, it is recognized by those of ordinary skill in the art that one or more features or characteristics can be compromised to achieve the desired overall system properties, depending on the specific application and implementation. These properties may include, but are not limited to, cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, maintainability, weight, manufacturability, ease of assembly, etc. Therefore, to the extent that any embodiment is described as not as ideal as other embodiments or prior art implementations in terms of one or more characteristics, these embodiments do not exceed the scope of the present disclosure and may be desirable for specific applications.

[0075] It will be understood that variations and modifications may be made in the foregoing constructions without departing from the concepts of the present disclosure, and it will be understood that these concepts are intended to be encompassed by the appended claims unless their language expressly states otherwise.

[0076] Reference numerals list

[0077] 10 Electric drive unit

[0078] 12 Heat exchanger

[0079] 14 Housing

[0080] 16 Central housing area

[0081] 18 Gearbox housing area

[0082] 20 Gear Box

[0083] 22 Storage Tanks

[0084] 24 Heat exchanger wall section

[0085] 26 Inner surface

[0086] 28 External surface

[0087] 30 Fluid Chamber

[0088] 32 Cover

[0089] 34 Electric Motor

[0090] 36 Stator

[0091] 38 Rotor

[0092] 40 Stator carrier

[0093] 42 Rotor shaft

[0094] 44 Fluid sheath

[0095] 46 Fluid sheath cavity

[0096] 48 First Fluid

[0097] 50 Second Fluid

[0098] 52 body

[0099] 54 Surface

[0100] 56 Protrusion

[0101] 58 Baffle

[0102] 60 base

[0103] 62 Distal end

[0104] 64 First protrusion

[0105] 66 Second protrusion

[0106] 68 The third salient

[0107] 70 Winding Flow Path

[0108] 72 U-shaped flow path

[0109] 74 Ribs

Claims

1. An electric drive unit, comprising: Electric motor; as well as a housing that houses the electric motor and includes a heat exchange wall portion that includes an inner surface that defines a fluid jacket cavity for conveying a first fluid and an outer surface that is opposite the inner surface and defines a fluid chamber for conveying a second fluid, wherein heat is transferred between the first fluid and the second fluid through the heat exchange wall portion.

2. The electric drive unit according to claim 1, wherein: The inner surface of the heat exchange wall portion is axially and circumferentially aligned with the outer surface of the heat exchange wall portion.

3. The electric drive unit according to claim 2, wherein: The electric motor includes a rotor and a stator positioned radially outwardly of the rotor, and wherein the stator is axially aligned with the heat exchange wall portion of the housing.

4. The electric drive unit according to claim 3, wherein: The fluid jacket cavity is defined by the inner surface of the heat exchange wall portion and a stator carrier, wherein a portion of the stator carrier is axially aligned with the stator and positioned radially outward of the stator.

5. The electric drive unit according to claim 3, wherein: The first fluid includes water and the second fluid is oil.

6. The electric drive unit according to claim 1, wherein: Heat is transferred from the second fluid to the first fluid through the heat exchange wall portion.

7. The electric drive unit according to claim 1, wherein: The outer surface of the heat exchange wall portion is formed with a base and a plurality of protrusions extending radially outward from the base.

8. The electric drive unit according to claim 7, further comprising: A cover is mounted to the housing and is arranged radially outward of the heat exchange wall portion such that the outer surface of the heat exchange wall portion and the cover cooperate to define the fluid chamber.

9. The electric drive unit according to claim 8, wherein: The cover includes a plurality of protrusions extending radially inwardly toward the outer surface of the heat exchange wall portion of the housing.

10. The electric drive unit according to claim 9, wherein: The plurality of protrusions of the cover are aligned with the plurality of protrusions of the outer surface of the heat exchange wall portion such that distal ends of the plurality of protrusions of the cover face distal ends of the plurality of protrusions of the outer surface of the heat exchange wall portion.

11. The electric drive unit according to claim 8, wherein: The outer surface of the heat exchange wall portion is also formed with baffles extending radially outwardly further from the base portion than the plurality of protrusions of the outer surface of the heat exchange wall portion extend radially outwardly from the base portion.

12. The electric drive unit according to claim 11, wherein: The cover includes baffles extending radially inwardly along the baffles formed by the outer surface of the heat exchange wall portion.

13. The electric drive unit according to claim 7, wherein: The plurality of projections extending radially outwardly from the base include: a first protrusion, the first protrusion having a certain height, width and length, the height being the distance the first protrusion extends outward from the base to the distal end of the first protrusion, and the length being greater than the width of the first protrusion, so that the first protrusion is elongated along the length direction of the first protrusion; and A second protrusion, the second protrusion having a certain height, width and length, the height being the distance the second protrusion extends outward from the base to the distal end of the second protrusion, and the length being greater than the width of the second protrusion, so that the second protrusion extends along the length direction of the second protrusion, wherein the first protrusion and the second protrusion are oriented so that the angular difference between the length direction of the first protrusion and the length direction of the second protrusion is greater than the angular difference between the height direction of the first protrusion and the height direction of the second protrusion.

14. An electric drive unit, comprising: A body having a surface defining a fluid chamber, wherein the surface is formed within the fluid chamber with a base and a plurality of protrusions extending outwardly from the base, the plurality of protrusions comprising: a first protrusion, the first protrusion having a certain height, width and length, the height being the distance the first protrusion extends outward from the base to the distal end of the first protrusion, and the length being greater than the width of the first protrusion, so that the first protrusion is elongated along the length direction of the first protrusion; and A second protrusion, the second protrusion having a certain height, width and length, the height being the distance the second protrusion extends outward from the base to the distal end of the second protrusion, and the length being greater than the width of the second protrusion, so that the second protrusion extends along the length direction of the second protrusion, wherein the first protrusion and the second protrusion are oriented so that the angular difference between the length direction of the first protrusion and the length direction of the second protrusion is greater than the angular difference between the height direction of the first protrusion and the height direction of the second protrusion.

15. The electric drive unit according to claim 14, wherein: The body is a housing that accommodates the electric motor, and the surface is an outer surface of a heat exchange wall portion of the housing.

16. The electric drive unit according to claim 15, wherein: The heat exchange wall portion includes an inner surface opposite the outer surface, wherein the inner surface defines a fluid jacket cavity.

17. The electric drive unit according to claim 16, wherein: The heat exchange wall portion is configured to transfer heat from a second fluid conveyed within the fluid chamber to a first fluid conveyed within the fluid jacket cavity.

18. The electric drive unit of claim 14, wherein: The body is a cover coupled to a housing housing an electric motor, wherein the cover and the housing define the fluid chamber.

19. The electric drive unit of claim 14, wherein: The plurality of protrusions further comprises: A third protrusion, the third protrusion having a certain height, width and length, the height being the distance the third protrusion extends outward from the base to the distal end of the third protrusion, and the length being greater than the width of the third protrusion, so that the third protrusion extends along the length direction of the third protrusion, wherein the third protrusion is oriented so that the angular difference between the length direction of the first protrusion and the length direction of the third protrusion is greater than the angular difference between the height direction of the first protrusion and the height direction of the third protrusion, the angular difference between the length direction of the second protrusion and the length direction of the third protrusion is greater than the angular difference between the height direction of the second protrusion and the height direction of the third protrusion, and the angular difference between the length direction of the first protrusion and the length direction of the third protrusion is greater than the angular difference between the length direction of the second protrusion and the length direction of the third protrusion.

20. An electric drive unit, comprising: Electric motor; a housing housing the electric motor and including an outer surface formed with a base and a plurality of projections extending radially outward from the base; as well as A cover is coupled to the housing and has a plurality of protrusions aligned with the plurality of protrusions of the outer surface of the housing, wherein the outer surface of the housing and the cover cooperate to define a fluid chamber for conveying a fluid.

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