End turn cooling assembly

Abstract

To provide an end turn cooling assembly for increased cooling efficiency in a battery electric vehicle (BEV).SOLUTION: A cooling assembly for an electric drive system in a battery electric vehicle includes: a gearbox fluid manifold assembly configured to couple to a radial directional surface of a stator of a rotating electric machine; an end cap fluid manifold assembly configured to couple to the radial directional surface of the stator of the rotating electric machine; or both the gearbox fluid manifold assembly and the end cap fluid manifold assembly.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] This application relates to battery electric vehicles (BEVs), and more particularly to rotating electric machines included in BEVs. [Background technology]

[0002]

[0002] Automobiles are increasingly relying on some form of electric propulsion. Automobiles may be referred to as battery electric vehicles (BEVs), which includes vehicles that rely partially on electric motors for propulsion, such as hybrid electric vehicles, and vehicles that rely solely on batteries and electric motors for propulsion. Given the inherent mobility of BEVs, the electric motors they contain may face a wide range of situations. And during operation, electric motors may generate a significant amount of heat. Increasing the cooling efficiency of BEVs in the automotive environment would be helpful. Summary of the Invention

[0003]

[0003] A cooling assembly for an electric drive system in a battery electric vehicle includes a gearbox fluid manifold assembly configured to couple to a radial surface of a stator of a rotating electric machine, an end cap fluid manifold assembly configured to couple to a radial surface of a stator of a rotating electric machine, or both a gearbox fluid manifold assembly and an end cap fluid manifold assembly. [Brief description of the drawings]

[0004] [Figure 1]

[0004] FIG. 1 is a perspective view illustrating an implementation form of an electric drive unit. [Diagram 2]

[0005] FIG. 2 is a cross-sectional view illustrating an implementation of an electric drive unit. [Diagram 3]

[0006] FIG. 2 is a perspective view illustrating a portion of an implementation of a cooling assembly included in an electric drive unit. [Figure 4]

[0007] FIG. 13 is another perspective view illustrating a portion of an implementation of a cooling assembly included in an electric drive unit. [Diagram 5]

[0008] FIG. 13 is another perspective view illustrating a portion of an implementation of a cooling assembly included in an electric drive unit. [Figure 6]

[0009] FIG. 2 is a perspective view illustrating a portion of an implementation of a cooling assembly included in an electric drive unit. [Figure 7]

[0010] FIG. 13 is another perspective view illustrating a portion of an implementation of a cooling assembly included in an electric drive unit. [Figure 8]

[0011] FIG. 2 is a cross-sectional view illustrating a portion of an implementation of a cooling assembly included in an electric drive unit. [Figure 9]

[0012] 1 is another perspective cross-sectional view illustrating a portion of an implementation of a cooling assembly included in an electric drive unit. [Figure 10]

[0013] FIG. 1 is a plan view illustrating a portion of an implementation of a cooling assembly included in an electric drive unit. [Figure 11]

[0014] FIG. 13 is another plan view illustrating a portion of an implementation of a cooling assembly included in an electric drive unit. [Figure 12]

[0015] FIG. 2 is a cross-sectional view illustrating a portion of an implementation of an electric drive unit. [Figure 13]

[0016] FIG. 2 is another cross-sectional view illustrating a portion of an implementation of an electric drive unit. [Figure 14]

[0017] FIG. 2 is another cross-sectional view illustrating a portion of an implementation of an electric drive unit. [Figure 15]

[0018] FIG. 2 is an exploded view illustrating a portion of an implementation of a cooling assembly included in an electric drive unit. [Figure 16]

[0019] 1 is a perspective cross-sectional view illustrating a portion of an implementation of a cooling assembly included in an electric drive unit; [Figure 17]

[0020] FIG. 2 is a perspective view illustrating a portion of an implementation of a cooling assembly included in an electric drive unit. [Figure 18]

[0021] FIG. 1 is a plan view illustrating a portion of an implementation of a cooling assembly included in an electric drive unit. [Figure 19]

[0022] FIG. 1 is a perspective view illustrating a portion of an implementation of a gearbox fluid manifold assembly included in a cooling assembly. [Figure 20]

[0023] FIG. 1 is a perspective view illustrating a portion of an implementation of a gearbox fluid manifold assembly included in a cooling assembly. [Figure 21]

[0024] FIG. 1 is a perspective view illustrating a portion of an implementation of a gearbox fluid manifold assembly included in a cooling assembly. [Figure 22]

[0025] FIG. 1 is a perspective view illustrating a portion of an implementation of a gearbox fluid manifold assembly included in a cooling assembly. [Figure 23]

[0026] FIG. 1 is a perspective view illustrating a portion of an implementation of a gearbox fluid manifold assembly included in a cooling assembly. [Figure 24]

[0027] FIG. 1 is a perspective view illustrating a portion of an implementation of a gearbox fluid manifold assembly included in a cooling assembly. [Diagram 25]

[0028] FIG. 1 is a perspective view illustrating a portion of an implementation of a gearbox fluid manifold assembly included in a cooling assembly. [Figure 26]

[0029] FIG. 1 is a perspective view illustrating a portion of an implementation of an electric drive system. [Figure 27]

[0030] FIG. 2 is a cross-sectional view illustrating a portion of an implementation of an electric drive system. [Figure 28]

[0031] FIG. 1 is a cross-sectional view illustrating a portion of an implementation of a gearbox fluid manifold assembly. [Figure 29]

[0032] FIG. 1 is a perspective view illustrating a portion of an implementation of a gearbox fluid manifold assembly included in a cooling assembly. [Diagram 30]

[0033] FIG. 13 is a cross-sectional view illustrating a portion of an implementation of a gearbox fluid manifold assembly included in a cooling assembly. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0005]

[0034] An electric drive system (EDS) may include a rotating electric machine, a gearbox coupled to an output of the rotating electric machine, and power electronics that control electrical power stored in a vehicle battery that is supplied to the rotating electric machine. The EDS may use fluid to cool and / or lubricate its components. For example, the gearbox may use a lubricating fluid to both lubricate and cool the gear components contained in the gearbox. The fluid may also be supplied to the rotating electric machine for both lubrication and thermal management. The rotating electric machine may include a stator assembly having stator windings received within radially inwardly facing stator slots, and a rotor assembly including an output shaft received concentrically within the stator assembly. The stator windings may be inserted within the stator slots using any one of a variety of stator winding techniques. Regardless of the winding technique selected, a portion of the windings extends axially beyond the stator and may be referred to as an end turn.

[0006]

[0035] The end-turn portions of the stator windings located outside the stator may be at a different temperature than the portions of the stator windings located within the stator slots of the stator. In the past, various techniques have been used to increase the cooling effect on the end-turns, such as spraying fluid on the exposed end-turns. As part of a fluid circulation circuit that channels fluid through the rotating electrical machine, it helps to increase the efficiency with which the end-turns are cooled as well as the stator itself.

[0007]

[0036] 1 and 2, an electric drive unit 10 having a cooling assembly 12 may be installed in a battery electric vehicle (BEV) (not shown) and may include a rotating electric machine 14 (sometimes referred to as an electric motor) having an output shaft 16 coupled to a gearbox assembly 18, and power electronics 20 that regulate the supply of electrical power provided to the rotating electric machine 14 from a vehicle battery (not shown). The term "BEV" may refer to a vehicle that is propelled in whole or in part by an electric motor. BEVs may refer to electric vehicles, plug-in electric vehicles, hybrid electric vehicles, and battery powered vehicles. The rotating electric machine 14 may include a stator assembly 22 in which a stator 24 has axially extending stator fluid channels 26. The stator 24 may be formed from a stack of axially extending metal plates that are joined together to form a unitary structure. Each plate may include openings that may form the stator fluid channels 26 when aligned with the openings in the other plates. The plates may be bonded together in any one of a number of different ways. The stator 24 includes stator slots 28 that receive the stator windings 30. As mentioned above, the stator windings 30 may be formed in any one of a number of different ways. For example, the stator windings 30 may be cascaded, woven, or hairpin. The portions of the stator windings 30 that reside outside the stator slots 28 before the stator windings 30 re-enter the slots 28 may be referred to as end turns 32. The end turns 32 in this implementation may be encapsulated in a potting compound 34 such that the end turns 32 are not exposed to the ambient environment within the electric drive unit 10. The stator 24 may be received within a stator housing 36 that closely conforms to the outer surface of the stator 24. A gearbox fluid manifold assembly 38 may be coupled to a radial face 40 of the stator 24 adjacent the gearbox 18 to receive and direct the fluid closely around the contours of the end turns 32 at the radial face 40.The gearbox fluid manifold assembly 38 may then supply the fluid to a radial face 40 of the stator 24 where the fluid may enter stator fluid channels 26 that extend axially through the stator 24 to an opposite end of the stator 24. An end cap fluid manifold assembly 42 may couple to another radial face 44 of the stator 24 at the opposite end of the stator 24 and direct the fluid closely around the end turns 32 at the opposite end.

[0008]

[0037] The rotor assembly 46 may include a rotor 48 and an output shaft 16 coupled to the rotor 48 such that angular displacement of the rotor 48 relative to the shaft 16 is prevented. The rotor 48 may be configured in different ways depending on the type of rotating electric machine 14. In one implementation, the rotor 48 may include permanent magnets (not shown) spaced circumferentially around the rotor 48. The rotating electric machine 14 in this implementation may be a permanent magnet synchronous machine. However, other types of rotating machines are possible that use the cooling assemblies described herein. The output shaft 16 may include an end 50 that mechanically couples with a gearbox assembly 18. The gearbox assembly 18 may be implemented in any number of different configurations depending on the needs of the BEV. Here, the output shaft 16 may include an end 50 having splines that engage with a helical gear 52. The helical gear 52 may be rotatably coupled to a differential 54 that transfers the rotational motion and torque generated by the output shaft 16 to a drive shaft that may be coupled to drive wheels of the BEV.

[0009]

[0038] The cooling assembly 12 may include a gearbox fluid manifold assembly 38, an end cap fluid manifold assembly 42, and a stator fluid channel 26. FIGS. 3-14 illustrate an implementation of the end cap fluid manifold assembly 42 including an outer plate 56 and an inner plate 58 coupled to one another, each including a complementarily shaped fluid guide 60 that receives fluid from a source, passes the fluid over the end turns 32, and provides the fluid to the stator fluid channel 26. In this implementation, the plates 56, 58 may be substantially planar and have an inner diameter shaped and sized to receive the output shaft 16 of the rotating electric machine 14. The outer diameter of the plates 56, 58 may be sized and shaped to engage the radial surface 40 of the stator 24 and form a fluid-tight seal. An O-ring may be positioned between the inner diameter of the plates 56, 58 and the output shaft 16. A plurality of fluid inlets 64 may receive fluid from a fluid source (not shown). In one implementation, the fluid source may be a sump of the gearbox assembly 18 that contains the gear lubricant.

[0010]

[0039] Each of the outer plate 56 and the inner plate 58 may include a curved fluid guide 60 extending from one surface of the plate 56, 58. The fluid guide 60 may be a surface extending at a right angle from the surface of the plate 56, 58 and may be similarly shaped to form a fluid channel 66 therebetween. The curved fluid guide 60 may be formed on the surfaces of the outer plate 56 and the inner plate 58 that face each other when the outer plate 56 is joined with the inner plate 58. The facing relationship may bring the curved fluid guides 60 into close proximity to each other while leaving a space between the guides 60 that may function as a fluid channel 66. The distance between the fluid guides 60 may be selected based on the desired fluid flow characteristics of the fluid channel 66. The fluid guides 60 may be shaped and positioned apart from each other to increase the speed at which the fluid flows. The outer plate 56 may include an annular cap portion 68 sized and shaped to receive a correspondingly shaped portion 70 of the inner plate 58 so that the curved fluid guides 60 are positioned adjacent to one another with a predetermined gap between the guides 60, thereby establishing fluid channels 66 within the end cap fluid manifold assembly 42. The outer plate 56 may also be integrally formed with a housing 72 and electrical connections for the power electronics 20 used to control the rotating electric machine 14.

[0011]

[0040] The inner plate 58 may be molded to closely form around the end turns 32 extending axially from the stator 24. The inner plate 58 may include an end turn receiving portion 74 shaped to closely fit and mate with the end turns 32. The end turn receiving portion 74 may have an outer surface adjacent to and in fluid communication with the curved fluid guides 60 of the inner plate 58. The outer surface of the end turn receiving portion 74 may also engage the outer plate 56 as an attachment point and / or to radially locate the curved fluid guides relative to one another, thereby defining the fluid channels 66 in the end cap fluid manifold assembly 42. An end cap 62 may be coupled to the stator housing 36 to enclose the assembly 42 within the electric drive unit 10 and form a fluid-tight seal with the housing 36.

[0012]

[0041] Fluid may be received from a fluid source and communicated through the fluid channels 66 between the fluid guides 60 of the outer plate 56 and the fluid guides 60 of the inner plate 58. In this implementation, a plurality of fluid supply ports 76 may receive fluid from a fluid source and supply fluid to the fluid channels 66 between the inner plate 58 and the outer plate 56. The fluid channels 66 may pass fluid to the end turn receiving portion 74 such that the fluid flow on its outer surface is in close proximity to the end turns 32. The fluid may exit the fluid outlet ports 78 and flow between the outer surface of the stator 24 and the radially inward facing surface of the stator housing 36. The stator fluid channels 26 may receive and communicate fluid towards the gearbox fluid manifold assembly 38.

[0013]

[0042] 15-29 illustrate implementations of the gearbox fluid manifold assembly 38. The gearbox fluid manifold assembly 38 may be axially positioned between the gearbox assembly 18 and the stator 24. The gearbox fluid manifold assembly 38 may receive fluid traveling along the stator fluid channels 26 from the end cap fluid manifold assembly 42 and pass the fluid over the end turns 32 proximate the gearbox fluid manifold assembly 38. The gearbox fluid manifold assembly 38 may channel the received fluid in close proximity around the end turns 32. The gearbox fluid manifold assembly 38 may include an outer segmented guide 82, an inner segmented guide 84, an outer ring 86, an inner ring 88, and a retainer 90. The components of the gearbox fluid manifold assembly 38 may be axially and / or concentrically positioned to closely match the shape of the end turns 32 to channel the fluid in close proximity to or over the end turns 32. In this implementation, the end turns 32 may be shaped such that at least a portion of the end turns 32 may extend in a non-parallel direction relative to the shaft axis of rotation (x). That is, during winding of the stator, the windings 30 may be positioned within the stator slots 28 such that the end turns 32 extend substantially parallel to the shaft axis of rotation (x). After winding, the end turns 32 may be shaped to articulate at a non-parallel angle relative to the shaft axis of rotation (x). Considering the articulating end turns 32, the outer segmented guide 82 and the inner segmented guide 84 may initially be present in a multi-piece assembly and later joined at one or more locations using fasteners 92 when the guides 82, 84 are positioned within the gearbox fluid manifold assembly 38, thereby adapting the shape of the end turns 32. Each of the outer segmented guide 82 and the inner segmented guide 84 may include a flange 94 that is angled or inclined to position the flange 94 substantially parallel to the end turn 32 and in close conformance with the surface of the end turn 32.

[0014]

[0043] In one implementation, the inner segmented guide 84' may be formed from a single, integral structure, as shown in FIGS. 29 and 30. In this implementation, the inner segmented guide 84' may first be formed from an annular length of tubing. The end turns 32 may be positioned within the stator 24 during assembly to extend substantially parallel to the shaft rotation axis (x) away from the radial face 40 of the stator 24. The inner segmented guide 84' may be positioned concentrically with the end turns 32. A tool including a mandrel 102 and a fixture 104 may be used to shape the inner segmented guide 84' such that one end of the guide 84' has a smaller diameter than the other end of the guide 84' and closely matches the shape of the end turns 32. The mandrel 102 may be a cylindrical post having an outer shape that matches the desired shape of the inner segmented guide 84'. The fixture 104 may also be configured to have a shape that matches the desired shape of the inner segmented guide 84'. The mandrel 102 can be positioned within the inner diameter of the guide 84' and the fastener 104 can be moved radially relative to the shaft rotation axis (x) toward the outer surface of the guide 84' such that the mandrel 102 and fastener 104 engage the guide 84' and shape it in situ. The mandrel 102 and fastener 104 can then be removed and the inner segmented guide 84' can maintain its shape. After the inner segmented guide 84 is shaped, the end turns 32 can be mechanically bent or deformed to extend in an orientation non-parallel to the shaft rotation axis (x). The new orientation of the end turns 32 can be in close proximity to the inner segmented guide 84'.

[0015]

[0044] The outer ring 86 may engage the inner segmented guide 84 at the distal end of the end turn 32 to help move fluid around the end turn 32. The outer ring 86 may be formed from an unbroken continuous element that caps the end turn 32 and couples with the inner segmented guide 84 to enclose the end turn 32. The coupling may be accomplished by a snap function in which openings receive studs that hold the elements together. Fluid may flow between a flange 94 of the outer segmented guide 82 and a flange 94 of the inner segmented guide 84 and around the outer surface of the outer ring 86. The outer surface of the outer ring 86 may include a shaped outer surface 96 that is non-parallel to the shaft rotation axis (x) over a length and parallel to the axis (x) over a portion. The inner ring 88 may be held in place by a number of studs 98 that are positioned in close proximity to the shaped outer surface 96 of the outer ring 86 and extend from the gearbox assembly 18. The gap between the molded outer surface 96 of the outer ring and the surface of the inner ring 88 facing the outer ring 86 can direct the fluid to a fluid exit orifice 100 in the gearbox assembly 18 to direct the fluid to the gears in the assembly 18.

[0016]

[0045] It should be understood that the above is a description of one or more embodiments of the present invention. The present invention is not limited to the specific embodiment(s) disclosed herein, but rather is defined only by the following claims. Furthermore, statements contained in the above description should not be construed as limitations on the definition of terms used in the claims or the scope of the present invention, except where a term or phrase is expressly defined above with respect to a specific embodiment. Various other embodiments and various changes and modifications of the disclosed embodiment(s) will be apparent to those skilled in the art. All such other embodiments, changes and modifications are intended to fall within the scope of the appended claims.

[0017]

[0046] As used in this specification and claims, the terms "eg," "for example," "for instance," "such as," and "like," as well as the verbs "comprising," "having," and "including" and other verb forms thereof, when used in conjunction with a list of one or more components or other items, are each to be construed as open-ended, meaning that the list should not be construed as excluding other additional components or items. Other terms are to be construed using their broadest reasonable meaning unless used in a context requiring a different interpretation.

Claims

1. 1. A cooling assembly for an electric drive system in a battery electric vehicle, comprising: an end cap fluid manifold assembly configured to couple to a radial surface of a stator of a rotating electrical machine, the end cap fluid manifold assembly comprising: an outer plate having an outer plate fluid guide; an inner plate having an inner plate fluid guide and an end turn receiving portion configured to abut an end turn of a stator winding in the rotating electrical machine; a fluid channel formed between the outer plate fluid guide and the inner plate fluid guide, the fluid channel configured to receive a fluid and communicate the fluid over the end turns; A cooling assembly having

2. The cooling assembly of claim 1 , wherein the end cap fluid manifold assembly is positioned adjacent to power electronics used to control the rotating electric machine.

3. The cooling assembly of claim 1 , wherein the fluid from the fluid channel is communicated to a stator fluid channel in a stator.

4. The cooling assembly of claim 1 , wherein an end cap fluid manifold assembly is positioned concentrically about an output shaft of the rotating electrical machine.

5. The cooling assembly of claim 1 , further comprising a baffle positioned within the fluid channel.

6. The cooling assembly of claim 1 , further comprising a corresponding receiving portion formed on the inner plate that radially positions the outer plate fluid guide relative to the inner plate fluid guide.

7. The cooling assembly of claim 1 , wherein the end turns are encapsulated in a potting compound.

8. 1. A cooling assembly for an electric drive system in a battery electric vehicle, comprising: a gearbox fluid manifold assembly configured to couple to a radial face of a stator of a rotating electrical machine, the gearbox fluid manifold assembly comprising: an outer segmented guide including a flange forming a portion of the fluid channel and a plurality of segments connecting at one or more circumferential locations; an inner segmented guide including a flange forming another portion of the fluid channel and a plurality of segments connecting at one or more circumferential locations, whereby the inner segmented guide is configured to abut an end turn of the rotating electrical machine; an outer ring coupled to the inner segmented guide and also configured to abut the end turns of the rotating electrical machine; an inner ring coupled to the outer ring and forming a portion of the fluid channel; a retaining ring axially restraining the inner ring relative to the gearbox fluid manifold assembly; A cooling assembly having

9. The cooling assembly of claim 8 , wherein the gearbox fluid manifold assembly is positioned between a stator and a gearbox assembly of the rotating electrical machine.

10. The cooling assembly of claim 8 , wherein fluid from the fluid channel is communicated to the gearbox assembly.

11. The cooling assembly of claim 8 , wherein the gearbox fluid manifold assembly is positioned concentrically about an output shaft of the rotating electrical machine.

12. The cooling assembly of claim 8 , further comprising a baffle positioned within the fluid channel.

13. The cooling assembly of claim 8 , wherein the end turns are encapsulated in a potting compound.

14. The cooling assembly of claim 8 , wherein the inner segmented guide is unitary and formed in situ.

15. 1. A cooling assembly for an electric drive system in a battery electric vehicle, comprising: a gearbox fluid manifold assembly configured to couple to a radial face of a stator of a rotating electrical machine, the gearbox fluid manifold assembly comprising: an outer plate having an outer plate fluid guide; an inner plate having an inner plate fluid guide and an end turn receiving portion that abuts an end turn of a stator winding in the rotating electrical machine; a fluid channel formed between the outer plate fluid guide and the inner plate fluid guide and configured to receive a fluid and communicate the fluid over the end turns, wherein the fluid channel is in fluid communication with a stator fluid channel within a stator. having The cooling assembly includes: an end cap fluid manifold assembly coupled to another radial surface of the stator of the rotating electrical machine, the end cap fluid manifold assembly comprising: an outer segmented guide including a flange forming a portion of a fluid channel and a plurality of segments connecting at one or more circumferential locations, wherein the fluid channel receives fluid from the stator fluid channel; an inner segmented guide including a flange forming another portion of the fluid channel and a plurality of segments connecting at one or more circumferential locations, whereby the inner segmented guide abuts an end turn of the rotating electrical machine; an outer ring coupled to the inner segmented guide and also abutting the end turns of the rotating electrical machine; an inner ring coupled to the outer ring and forming a portion of the fluid channel; a retaining ring axially restraining the inner ring relative to the end cap fluid manifold assembly; A cooling assembly having

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