Cooling systems for electric motor components

Abstract

A coolant flow path configuration for an electric motor is disclosed herein. The coolant flow path configuration includes a coolant flow path channel defined on a radially outer surface of a stator lamination stack. The coolant flow path channel includes: a first axial end defined radially outward from a first set of coils; and a second axial end defined radially outward from a second set of coils away from the first set of coils.

Description

[0001] Incorporated by Reference

[0002] This application claims priority to U.S. Provisional Application No. 62 / 983,100, filed on February 28, 2020, and priority to U.S. Non-Provisional Application No. 17 / 182,587, filed on February 23, 2021, and the U.S. Non-Provisional Applications are incorporated herein by reference in their entirety. Technical Field

[0003] The present disclosure relates to cooling systems. Background Art

[0004] There is a need to provide cooling systems that utilize electric motor components. However, in these cooling systems, routing the secondary cooling flow through the transmission housing is problematic. There is not enough space between the electric motor and the transmission housing in existing configurations, particularly in the radial direction.

[0005] To meet performance requirements, the coolant (ie, coolant, oil, etc.) must be able to contact both sides of the electric motor coils to provide adequate and uniform heat transfer. Referring to the figures, it is difficult to provide coolant flow to the far or right hand side of the electric motor.

[0006] It would be desirable to provide a reliable and efficient way to provide oil or coolant flow to distal portions of stator coils in an electric motor. Summary of the invention

[0007] A cooling system is disclosed herein that provides an improved coolant flow arrangement to cool a distal end of a stator and coils of the stator.

[0008] A coolant flow path configuration for an electric motor is also disclosed herein. The coolant flow path configuration includes a coolant flow path channel defined on a radially outer surface of a stator lamination stack. The coolant flow path channel includes: a first axial end defined radially outward from a first set of coils; and a second axial end defined radially outward from a second set of coils away from the first set of coils.

[0009] In one embodiment, a cooling arrangement for an electric motor is disclosed. The arrangement includes a housing defining an inlet for a coolant and partially defining a main flow path (F). A stator carrier is positioned adjacent to the housing and partially defines the main flow path (F). A busbar carrier is positioned radially inward from the stator carrier and partially defines the main flow path (F). A stator is arranged inside the stator carrier. A plurality of coils are also provided, including: a first group of proximal coils, the first group of proximal coils being arranged adjacent to the busbar carrier and at a first axial end of the stator; and a second group of distal coils, the second group of distal coils being arranged at a second axial end of the stator. A main flow path (F) is directed through a chamber defined by the housing, the stator carrier and the busbar carrier, and is divided into: (i) a first flow path (F1) directed radially inward to a first group of proximal coils, and (ii) a second flow path (F2) directed axially outward to a second group of distal coils.

[0010] The arrangement further comprises a sealant applied between components of the arrangement. In one embodiment, the sealant is applied to at least one of: (i) a first location defined between the housing and the busbar carrier, (ii) a second location defined on a radially outer surface of the busbar carrier, and (iii) a third location defined between the busbar carrier and the stator.

[0011] In one embodiment, the stator is formed as a lamination stack.

[0012] The second flow path (F2) is partially defined by at least one axially extending channel formed on the radially outer surface of the stator. The at least one channel extends the entire axial extent of the stator. The at least one channel is formed as a hemispherical recess on the stator. The at least one channel may include a plurality of channels spaced apart from each other in the circumferential direction. The radially inner surface of the stator carrier partially defines the at least one channel.

[0013] In one embodiment, the arrangement further comprises an O-ring mounted on the housing and surrounding the main flow path (F).

[0014] The radially outer surface of the busbar carrier comprises projections which extend radially outwards and limit the main flow path (F).

[0015] The terminal end portions of the first flow path ( F1 ) and the terminal end portions of the second flow path ( F2 ) are each dispersed to corresponding groups of coils in the circumferential direction.

[0016] The first set of proximal coils and the second set of distal coils are each mounted in a respective coil former, and each coil former is positioned directly adjacent to the stator.

[0017] The arrangement may further comprise a valve in the housing that regulates the flow of fluid into the housing.

[0018] In another embodiment, a cooling system for an electric motor is provided. The cooling system includes a main flow path (F) originating from the interior of a housing of the electric motor. The main flow path (F) is directed from the housing through an O-ring attached to the housing, and the main flow path (F) is directed into a chamber partially defined by the housing, a busbar carrier, and a stator carrier. The chamber divides the main flow path (F) into a first flow path (F1) and a second flow path (F2). The first flow path (F1) extends radially inward from the chamber and extends toward a first group of coils adjacent to the busbar carrier. The second flow path (F2) extends axially away from the chamber within an axially extending channel defined on a radially outer surface of the stator, and the second flow path (F2) is directed toward a second group of coils. The second group of coils is away from the first group of coils.

[0019] Other implementations are disclosed herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The foregoing summary and the following detailed description will be better understood when read in conjunction with the accompanying drawings which illustrate preferred embodiments of the present disclosure. In the drawings:

[0021] Figure 1 is a side cross-sectional view of an electric motor including a cooling system according to the present disclosure.

[0022] Figure 2 It is along Figure 1 A cross-sectional view taken along line AA.

[0023] Figure 3A yes Figure 1 A cross-sectional side view of an electric motor and cooling system including annotations to show the coolant flow path.

[0024] Figure 3B yes Figure 3A A three-dimensional view of the joint between the stator, busbar carrier and coil former.

[0025] Figure 3C yes Figure 3A A perspective view of a busbar carrier is shown showing certain parts of the busbar carrier.

[0026] Figure 3D yes Figure 3A, shows an enlarged section of a busbar carrier in a perspective view in a further region comprising openings or channels for a coolant.

[0027] Figure 4 is another cross-sectional view of an electric motor illustrating the coolant flow path in the region of the busbar carrier and the stator carrier.

[0028] Figure 5A is another cross-sectional view illustrating the coolant flow path from the busbar carrier and stator carrier downward toward the coil former and the proximal / left coil.

[0029] Figure 5B is a front plan view of the coolant flow path to the proximal / left coil.

[0030] Figure 5C is an enlarged cross-sectional view showing the coolant flow path from the busbar carrier downward toward the proximal / left coil.

[0031] Fig. 6A is another cross-sectional view illustrating the coolant flow path from the busbar carrier axially toward the distal / right coil.

[0032] Figure 6B is a front plan view illustrating the coolant flow path to the distal / right coil.

[0033] Figure 6C is an enlarged front view of the passage extending axially through the stator between the proximal / left-hand coil and the distal / right-most coil. DETAILED DESCRIPTION

[0034] Certain terms are used in the following description for convenience only and are not limiting. "Axially" refers to directions along the axis (X) of the assembly. "Radially" refers to directions inward and outward from the axis (X) of the assembly. "Circumferentially" refers to directions extending along an arc or circumference of a corresponding element relative to the axis (X) of the assembly.

[0035] Reference to a list of items referenced as "at least one of a, b, or c" (where a, b, and c represent the listed items) refers to any single item of items a, b, or c, or a combination of a, b, or c. The terminology includes the words specifically noted above, derivatives thereof, and words of similar meaning.

[0036] from Figure 1Initially, the electric motor 10 is generally illustrated as including the following components: housing 15; O-rings 20; sealant 25; busbar carrier 30; stator carrier 35; stator 40; proximal / left coil 45; distal / right coil 50; and coil formers 55, 60. More detailed features of each of these major components are described herein. Coolant is provided to features of the electric motor 10 via flow paths (F, F1, F2), and modifications to the electric motor 10 will be described in more detail herein. As used herein, the term coolant refers to any liquid or fluid that is directed through the electric motor 10, such as automatic transmission fluid (ATF).

[0037] The terms left and right are used herein with reference to a set of drawings. One of ordinary skill in the art will understand that these terms are relative based on a reference frame. Thus, the term distal is associated with the right coil and the term proximal is associated with the left coil. The term distal is used herein with reference to the relative position of components of the electric motor and is used to refer to the relative spacing between components or to a particular reference frame.

[0038] The term busbar carrier 30 is used herein generally to refer to an electrical junction housing or carrier.

[0039] The term stator 40 is generally used to refer to any type of stator in the present disclosure. In one embodiment, the stator 40 is formed as a laminated stack. It will be appreciated by those of ordinary skill in the art that the stator 40 can be formed according to a variety of methods. The terms stator and stator lamination stack are generally used interchangeably herein.

[0040] like Figure 2 As shown in FIG. 1 , the housing 15 includes a first housing component 15a and a second housing component 15b. The term housing 15 is generally used herein to refer to the first housing component 15a or the second housing component 15b, or to an embodiment in which a single-piece housing or an integral housing 15 is provided. It will be appreciated by those skilled in the art that the exact shape or arrangement of the housing 15 may vary.

[0041] The first housing component 15a includes a valve 16 that serves as an inlet for the coolant. The valve 16 may include a closed body, a seal, and any other known valve components that can provide a controllable flow path for the coolant to enter the first housing component 15a. Figure 2As shown in , the flow path (F), sometimes referred to herein as the main flow path or primary flow path, is directed from the valve 16 toward the end surface of the first housing component 15a, and is redirected in the opposite direction toward other components of the electric motor 10. It will be understood by those of ordinary skill in the art based on this disclosure that the flow path (F) can flow unimpeded from the valve 16 toward other components of the electric motor 10. Figure 2 The diagram illustrates how the flow path (F) is generally directed into the housing 15 and then out of the housing 15 toward the remainder of the electric motor 10 , ie, the coils, etc.

[0042] FIG. 3A to FIG. 3D The main flow path (F) is generally illustrated from the first housing component 15a through the O-ring 20 toward the second housing component 15b and the three-piece chamber 26, which is partially defined by the housing 15, the busbar carrier 30 and the stator carrier 35. A protrusion 32 is formed on the busbar carrier 30 to provide an interference or blocking feature to direct the flow path (F) in the desired direction. The sealant 25 is provided at least at FIG. 3A to FIG. 3C , and the combination of sealant 25 and protrusion 32 ensures that the flow path (F) is generally directed radially downward toward the left / proximal coil 45 and axially toward the right / distal coil 50. The sealant 25 is applied to at least one of the following locations: (i) a first location defined between the housing 15 and the busbar carrier 30, (ii) a second location defined on the radial outer surface of the busbar carrier 30, or (iii) a third location defined between the busbar carrier 30 and the stator 40. It will be understood by those of ordinary skill in the art that the sealant 25 can be applied to various other joints and locations to provide the desired orientation of the flow path (F). In one embodiment, the sealant 25 is a gasket-grade sealant, such as a silicone-based sealant. The sealant 25 is compatible with ATF. It will be understood by those skilled in the art based on this disclosure that any combination of sealant 25 and / or mechanical protrusions or interference elements 32 may be provided to ensure that the flow path (F) is directed radially downward from the housing 15 to the busbar carrier 30, through the opening or passage 31 defined in the busbar carrier 30, and directed radially downward toward the left / proximal coil 45 and the coil former 55. The combination of sealant 25 and / or mechanical protrusions or interference elements 32 restricts any flow of coolant in the circumferential direction while maintaining the flow path (F) in the direction shown in the drawings.

[0043] Figure 4The main flow path (F) is illustrated traveling from the three-piece chamber in two directions: radially inward toward the left / proximal coil 45 (indicated by the first flow path (F1)) and axially outward toward the right / distal coil 50 (indicated by the second flow path (F2)).

[0044] The first flow path (F1) is directed toward the coil former 55 and the left / proximal coil 45. FIG. 5A to FIG. 5C The second flow path (F2) is directed axially outward toward the right / distal coil 50, which is shown in more detail in FIG. FIG. 6A to FIG. 6C is shown in more detail in .

[0045] like Figure 5A As shown in FIG. 1 , the first flow path ( F1 ) is directed radially inwardly via the busbar carrier 30 toward the left / proximal coil 45 and the coil former 55 . Figure 5C An enlarged view of this junction is shown to illustrate how the first flow path (F1) is directed between the busbar carrier 30 and the coil former 55 toward the left / proximal coil 45. Figure 5B As shown in more detail in , once the first flow path ( F1 ) reaches this junction, the first flow path ( F1 ) is then distributed circumferentially in the left / proximal coil 45 .

[0046] FIG. 6A to FIG. 6C A second flow path (F2) is shown, which is directed along a channel 42 defined in the stator 40. The profile of the channel 42 is Figure 6C , which illustrates a channel 42 having a hemispherical shape. It will be appreciated by those skilled in the art that the size, shape, and geometry of the channel 42 may vary to suit the performance requirements of a particular application. In one embodiment, the channel 42 is stamped into the stator lamination stack 40. However, other forming techniques may also be used.

[0047] In one aspect, no flow restricting modifications, such as sealant 25 and / or mechanical protrusions or interfering elements 32, are required in the area of ​​the distal / right coil 50. In other words, the flow path (F2) is not restricted by any secondary or additional sealant or interfering elements and flows freely through the channel 42 and then radially inward and circumferentially to reach the distal / right coil 50.

[0048] Although the channel 42 is shown as extending radially inward from the radially outer side of the stator 40, it will be understood by those skilled in the art that the position of the channel 42 may be modified. A plurality of channels 42, 42' may be provided. For purposes of illustration, the second channel 42' is located at Figure 4 Although the second passage 42' is shown as a dotted line Figure 4 The passage 42 extends throughout the axial extent of the stator 40 so as to define an unobstructed path between the busbar carrier 30 and the junction defined between the coil former 60 holding the distal / right coil 50 and the axially extreme face of the stator carrier 35. Figure 6B The diagram shows Figure 5B Similar features are directed circumferentially to the distal / right coils 50 with respect to the second flow path ( F2 ) and coolant is injected between the distal / right coils 50 .

[0049] The arrangement disclosed herein generally provides an improved configuration for providing coolant to the left / proximal coil 45 and the distal / right coil 50. Providing coolant to the proximal / left coil 45 generally provides more options and flexibility because the proximal / left coil is close to the coolant source in the housing 15, while providing coolant to the distal / right coil 50 is more complicated. The configuration disclosed herein does not expand or otherwise modify the overall footprint or space required for the electric motor 10, which is a key design consideration. By providing the channel 42 in the stator 40, the present configuration also does not interfere with any of the other structural features of the electric motor 10. The flow paths (F1, F2) are provided by a combination of modifications to the shape of the stator carrier 35 and the shape of the busbar carrier 30, the use of the sealant 25, and the channel 42.

[0050] A method of providing coolant to an electric motor 10 is also disclosed herein. The method generally includes supplying coolant to the housing 15, such as via a valve 16. The method includes directing the coolant through the housing 15 and the O-ring 20 into a multi-piece chamber defined by the housing 15, the busbar carrier 30, and the stator carrier 35. From the multi-piece chamber, the method includes directing a main flow path (F) in two directions. The main flow path (F) is limited using a sealant 25 and a protrusion 32 on the busbar carrier 30. The method includes directing the main flow path (F1) into a first flow path (F1) that is directed radially inward toward a first set of coils, i.e., the proximal / left coil 45. The method also includes directing a second flow path (F2) axially away from the housing 15 to a distal portion of the stator. The second flow path (F2) is defined via a channel 42 defined on the stator 40. From the channel, the second flow path (F2) is directed radially inward toward the distal / right coil 50.

[0051] The embodiments disclosed herein provide a self-contained configuration or system that eliminates the need for the end user to consider the interfaces between the various subcomponents disclosed herein.

[0052] Thus, the present disclosure has been described in detail, and it should be understood and apparent to those skilled in the art that various physical changes may be made without changing the inventive concepts and principles embodied herein, and only a few of the various physical changes are exemplified in the detailed description of the present invention.

[0053] It should also be understood that various embodiments are possible that combine only parts of the preferred embodiments without altering the inventive concepts and principles embodied herein with respect to those parts.

[0054] Therefore, the present embodiment and optional configurations are considered in all aspects to be exemplary and / or illustrative rather than restrictive, the scope of the embodiment is indicated by the appended claims rather than the foregoing description, and therefore, all alternative embodiments and changes of the embodiment that fall within the equivalent meaning and equivalent range of the claims are included in the scope of the embodiment.

[0055] Description of Reference Numerals

[0056] Electric motor 10

[0057] Housing 15

[0058] Valve 16

[0059] O-ring 20

[0060] Sealant 25

[0061] Room 26

[0062] Busbar carrier 30

[0063] Path 31

[0064] Protrusion 32

[0065] Stator carrier 35

[0066] Stator or stator lamination pack 40

[0067] Channel 42

[0068] Proximal / Left Coil 45

[0069] Distal / right coil 50

[0070] Coil frame 55, 60

Claims

1. A cooling arrangement for an electric motor, the arrangement comprising: a housing defining an inlet for a coolant, the housing partially defining a main flow path (F); a stator carrier positioned adjacent the housing, the stator carrier partially defining the primary flow path (F); a busbar carrier located radially inwardly from the stator carrier and completely surrounded by the stator carrier, the busbar carrier partially defining the main flow path (F); a stator, the stator being arranged inside the stator carrier; as well as a plurality of coils, the plurality of coils comprising a first group of coils arranged at a first axial end of the stator adjacent to the busbar carrier and a second group of coils arranged at a second axial end of the stator away from the busbar carrier, wherein the main flow path (F) is directed through a chamber defined by the housing, the stator carrier and the busbar carrier into: (i) a first flow path (F1) directed radially inwardly to the first set of coils, and (ii) a second flow path (F2) directed axially outwardly to the second set of coils. 2 . The arrangement of claim 1 , further comprising a sealant applied between components of the arrangement.

3. The arrangement according to claim 2, wherein: The sealant is applied to at least one of: (i) a first location defined between the housing and the busbar carrier, (ii) a second location defined on a radially outer surface of the busbar carrier, or (iii) a third location defined between the busbar carrier and the stator.

4. The arrangement according to claim 1, wherein: The stator is formed as a laminated core.

5. The arrangement according to claim 1, wherein: The second flow path (F2) is defined in part by at least one axially extending channel formed on a radially outer surface of the stator.

6. The arrangement according to claim 5, wherein: The at least one channel extends the entire axial extent of the stator.

7. The arrangement according to claim 5, wherein: The at least one channel is formed as a hemispherical recess on the stator.

8. The arrangement according to claim 5, wherein: The at least one channel includes a plurality of channels spaced apart from each other in a circumferential direction.

9. The arrangement according to claim 5, wherein: The radially inner surface of the stator carrier partially defines a boundary of the at least one channel.

10. The arrangement of claim 1, further comprising an O-ring mounted on the housing and surrounding the main flow path (F).

11. The arrangement of claim 1, wherein: The radially outer surface of the busbar carrier comprises projections which extend radially outwards and limit the main flow path (F).

12. The arrangement of claim 1, wherein: The first flow path (F1) and the second flow path (F2) are each dispersed in the circumferential direction to the corresponding group of coils.

13. The arrangement of claim 1, wherein: The first set of coils and the second set of coils are each mounted in a respective bobbin, and each bobbin is positioned directly adjacent to the stator.

14. The arrangement of claim 1 further comprising a valve in the housing that regulates a flow rate of fluid into the housing.

15. A cooling system for an electric motor, the cooling system comprising: a main flow path (F), the main flow path originating from the interior of the housing of the electric motor, the main flow path (F) being led from the housing through an O-ring attached to the housing, the main flow path (F) being led into a chamber partially defined by the housing, a busbar carrier and a stator carrier, the busbar carrier being located radially inwards from the stator carrier and being completely surrounded by the stator carrier, wherein the chamber divides the main flow path (F) into a first flow path (F1) and a second flow path (F2); The first flow path (F1) extends radially inwardly from the chamber and toward a first set of coils adjacent the busbar carrier; and The second flow path (F2) extends axially away from the chamber within an axially extending channel defined on a radially outer surface of the stator and is directed toward a second set of coils that is distal to the first set of coils.

16. The cooling system according to claim 15, wherein: The main flow path (F) is restricted by a sealant applied to at least one of: (i) a first location defined between the housing and the busbar carrier, (ii) a second location defined on the radial outer surface of the busbar carrier, or (iii) a third location defined between the busbar carrier and the stator.

17. The cooling system according to claim 15, wherein: The first set of coils and the second set of coils are each mounted in a respective bobbin, and each bobbin is positioned directly adjacent to the stator.

18. The cooling system according to claim 15, wherein: The first flow path (F1) and the second flow path (F2) are each dispersed in the circumferential direction to the corresponding group of coils.

19. The cooling system according to claim 15, wherein: The passage extends the entire axial extent of the stator and is formed as a hemispherical recess on the stator.

20. A coolant flow path configuration for an electric motor, the coolant flow path configuration comprising: A coolant flow path channel defined on a radially outer surface of the stator lamination stack, wherein the coolant flow path channel comprises: a first axial end portion defined radially outwardly from the first set of coils; and a second axial end defined radially outwardly from a second set of coils distal from the first set of coils; The first axial end of the coolant flow path passage receives coolant flowing from a chamber partially defined by the housing, a busbar carrier, and a stator carrier, the busbar carrier being located radially inward from and completely surrounded by the stator carrier.

Images