End turn cooling assembly

Abstract

The present disclosure relates to an end turn cooling assembly, in particular, to a cooling assembly for an electric drive system in a battery electric vehicle, comprising: a gearbox fluid manifold assembly configured to be coupled to a radial face of a stator of a rotating electrical machine; an end cap fluid manifold assembly configured to be coupled to a radial face of a stator of the rotating electrical machine; or both the gearbox fluid manifold assembly and the end cap fluid manifold assembly.

Description

Technical Field

[0001] The present application relates to battery electric vehicles (BEVs), and more particularly, to a rotating electric machine included in a BEV. Background Art

[0002] Vehicles are increasingly reliant on some form of electric propulsion. These vehicles may be described as battery electric vehicles (BEVs), including vehicles that rely in part on an electric motor for propulsion (such as hybrid electric vehicles) as well as vehicles that rely solely on a battery and an electric motor for propulsion. Given the inherent mobility of a BEV, the electric motors included therein may be exposed to a wide range of conditions. During operation, the electric motors may generate a significant amount of heat. Improving the cooling efficiency of a BEV in the vehicle environment would be helpful. Summary of the invention

[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 face of a stator of a rotating electric machine; an end cover fluid manifold assembly configured to couple to a radial face of a stator of a rotating electric machine; or both the gearbox fluid manifold assembly and the end cover fluid manifold assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Figure 1 is a perspective view depicting an embodiment of an electric drive unit;

[0005] Figure 2 A cross-sectional view depicting an embodiment of an electric drive unit;

[0006] Figure 3 is a perspective view depicting a portion of an embodiment of a cooling assembly included in an electric drive unit;

[0007] Figure 4 is another perspective view depicting a portion of an embodiment of a cooling assembly included in an electric drive unit;

[0008] Figure 5 is another perspective view depicting a portion of an embodiment of a cooling assembly included in an electric drive unit;

[0009] Figure 6 is a perspective view depicting a portion of an embodiment of a cooling assembly included in an electric drive unit;

[0010] Figure 7 is another perspective view depicting a portion of an embodiment of a cooling assembly included in an electric drive unit;

[0011] Figure 8 is a cross-sectional view depicting a portion of an embodiment of a cooling assembly included in an electric drive unit;

[0012] Fig. 9 is another perspective cross-sectional view depicting a portion of an embodiment of a cooling assembly included in an electric drive unit;

[0013] Fig.10 is a plan view depicting a portion of an embodiment of a cooling assembly included in an electric drive unit;

[0014] Fig.11 is another plan view depicting a portion of an embodiment of a cooling assembly included in an electric drive unit;

[0015] Fig.12 is a cross-sectional view depicting a portion of an embodiment of an electric drive unit;

[0016] Fig.13 is another cross-sectional view depicting a portion of an embodiment of an electric drive unit;

[0017] Fig.14 is another cross-sectional view depicting a portion of an embodiment of an electric drive unit;

[0018] Fig.15 is an exploded view depicting a portion of an embodiment of a cooling assembly included in an electric drive unit;

[0019] Fig.16 is a perspective cross-sectional view depicting a portion of an embodiment of a cooling assembly included in an electric drive unit;

[0020] Fig.17 is a perspective view depicting a portion of an embodiment of a cooling assembly included in an electric drive unit;

[0021] Fig.18 is a plan view depicting a portion of an embodiment of a cooling assembly included in an electric drive unit;

[0022] Fig.19 is a perspective view depicting a portion of an embodiment of a gearbox fluid manifold assembly included in a cooling assembly;

[0023] Fig. 20 is a perspective view depicting a portion of an embodiment of a gearbox fluid manifold assembly included in a cooling assembly;

[0024] Fig.21 is a perspective view depicting a portion of an embodiment of a gearbox fluid manifold assembly included in a cooling assembly;

[0025] Fig. 22 is a perspective view depicting a portion of an embodiment of a gearbox fluid manifold assembly included in a cooling assembly;

[0026] Fig.23 is a perspective view depicting a portion of an embodiment of a gearbox fluid manifold assembly included in a cooling assembly;

[0027] Fig.24 is a perspective view depicting a portion of an embodiment of a gearbox fluid manifold assembly included in a cooling assembly;

[0028] Fig.25 is a perspective view depicting a portion of an embodiment of a gearbox fluid manifold assembly included in a cooling assembly;

[0029] Fig.26 is a perspective view depicting a portion of an embodiment of an electric drive system;

[0030] Fig. 27 is a cross-sectional view depicting a portion of an embodiment of an electric drive system;

[0031] Fig.28 is a cross-sectional view depicting a portion of an embodiment of a gearbox fluid manifold assembly;

[0032] Fig.29 is a perspective view depicting a portion of an embodiment of a gearbox fluid manifold assembly included in a cooling assembly; and

[0033] Fig.30 A cross-sectional view depicting a portion of an embodiment of a gearbox fluid manifold assembly included in a cooling assembly. DETAILED DESCRIPTION

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

[0035] The end turn portions of the stator windings that are located outside of the stator may be at a different temperature than the portions of the stator windings that are located within the stator slots of the stator. In the past, various techniques have been used to improve the cooling of the end turns, such as spraying fluid on the exposed end turns. This would help to improve the efficiency of cooling the end turns, as well as the stator itself as part of a fluid circulation loop that flows fluid through the rotating electrical machine.

[0036] Steering Figure 1 and Figure 2 , an electric drive unit 10 with a cooling assembly 12 may be installed in a battery electric vehicle (BEV; not shown), and includes a rotating electric machine 14 (sometimes also referred to as an electric motor) and a power electronic device 20, the rotating electric machine 14 having an output shaft 16 connected to a gearbox assembly 18, and a power electronic device 20 regulating the supply of power supplied from a vehicle battery (not shown) to the rotating electric machine 14. The term "BEV" may refer to a vehicle that is driven entirely or partially by an electric motor. BEV may refer to an electric vehicle, a plug-in electric vehicle, a hybrid electric vehicle, and a battery-driven vehicle. The rotating electric machine 14 may include a stator assembly 22 having a stator 24, and the stator 24 has an axially extending stator fluid channel 26. The stator 24 may be formed by a stack of axially extending metal plates that have been joined together to form an integral structure. Each plate may include an aperture that may form a stator fluid channel 26 when aligned with an aperture in another plate. The plates may be combined together in any of a number of different ways. The stator 24 includes a stator slot 28 that receives a stator winding 30. As described above, the stator windings 30 can be formed in any of a variety of different ways. For example, the stator windings 30 can be cascaded, interwoven, or hairpinned. The portions of the stator windings 30 that are located outside the stator slots 28 before the stator windings 30 re-enter the stator slots 28 can be referred to as end turns 32. In this embodiment, the end turns 32 can be encapsulated in a potting compound 34 so that the end turns 32 are not exposed to the surrounding environment inside the electric drive unit 10. The stator 24 can be received in a stator housing 36 that fits closely to the outer surface of the stator 24. The gearbox fluid manifold assembly 38 can be coupled to a radial face 40 of the stator 24 adjacent to the gearbox 18 to receive a fluid and direct the fluid to closely surround the contour of the end turns 32 at the radial face 40. The gearbox fluid manifold assembly 38 may then provide fluid to a radial face 40 of the stator 24 where the fluid may enter the stator fluid passages 26 extending axially through the stator 24 to an opposite end of the stator 24. An end cap fluid manifold assembly 42 may be coupled 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.

[0037] The rotor assembly 46 may include a rotor 48 and an output shaft 16, the output shaft 16 being coupled to the rotor 48 to prevent angular displacement of the rotor 48 relative to the shaft 16. The rotor 48 may be configured in different ways depending on the type of the rotary electric machine 14. In one embodiment, the rotor 48 may include permanent magnets (not shown) spaced circumferentially around the rotor 48. In this embodiment, the rotary electric machine 14 may be a permanent magnet synchronous electric machine. However, it is also possible for other types of rotary machines to use the cooling assembly described herein. The output shaft 16 may include an end 50 mechanically coupled to the gearbox assembly 18. Depending on the needs of the BEV, the gearbox assembly 18 may be implemented in any number of different configurations. Here, the output shaft 16 may include an end 50 having a spline, which meshes with a helical gear 52. The helical gear 52 may be rotatably coupled to a differential 54, which transmits the rotational motion and torque generated by the output shaft 16 to a drive shaft, which may be coupled to the drive wheels of the BEV.

[0038] The cooling assembly 12 may include a gearbox fluid manifold assembly 38 , an end cover fluid manifold assembly 42 , and the stator fluid passages 26 . Figures 3 to 14 An embodiment of an end cap fluid manifold assembly 42 is depicted that includes an outer plate 56 and an inner plate 58 coupled to one another, each including a complementary shaped fluid guide 60 that receives fluid from a source, passes the fluid through the end turns 32, and provides the fluid to the stator fluid passage 26. In this embodiment, the plates 56, 58 may be substantially planar with 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 with the radial surface 40 of the stator 24 and form a fluid tight seal. O-rings may be located between the inner diameters 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 embodiment, the fluid source may be an oil sump of the gearbox assembly 18 that includes gear lubricant.

[0039] The outer plate 56 and the inner plate 58 may each include a curved fluid guide 60 extending from one surface of the plates 56, 58. The fluid guide 60 may be a surface extending orthogonally from the surfaces of the plates 56, 58, and may have a similar shape to form a fluid channel 66 therebetween. When the outer plate 56 is coupled to the inner plate 58, 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. The facing relationship may allow the curved fluid guides 60 to be close to each other, leaving spaces between the guides 60 that may be used as the 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 so that the velocity of the fluid flow may be increased. The outer plate 56 may include an annular cover portion 68 that is sized and shaped to receive a correspondingly shaped portion 70 of the inner plate 58 such that the curved fluid guides 60 are positioned adjacent one another with defined gaps therebetween to establish the fluid passage 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 that control the rotating electric machine 14.

[0040] The inner plate 58 can be shaped to closely surround the end turns 32 extending axially from the stator 24. The inner plate 58 can include an end turn receiving portion 74 that is shaped to closely fit and fit over the end turns 32. The end turn receiving portion 74 can have an outer surface that is adjacent to and in fluid communication with the curved fluid guides 60 on the inner plate 58. The outer surface of the end turn receiving portion 74 can also serve as an attachment point to engage the outer plate 56 and / or radially position the curved fluid guides relative to each other, thereby defining a fluid passage 66 within the end cap fluid manifold assembly 42. The end cap 62 can be coupled to the stator housing 36 to enclose the assembly 42 within the electric drive unit 10 and form a fluid tight seal adjacent the housing 36.

[0041] Fluid may be received from a fluid source and delivered through the fluid passage 66 between the fluid guides 60 of the outer plate 56 and the inner plate 58. In this embodiment, a plurality of fluid supply ports 76 may receive fluid from a fluid source and supply fluid to the fluid passage 66 between the inner plate 58 and the outer plate 56. The fluid passage 66 may deliver fluid to the end turn receiving portion 74 so that the fluid flow on the outer surface is in close proximity to the end turns 32. The fluid may exit the fluid outlet 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 passage 26 may receive the fluid and deliver the fluid toward the gearbox fluid manifold assembly 38.

[0042] Figures 15 to 29An embodiment of a gearbox fluid manifold assembly 38 is depicted. The gearbox fluid manifold assembly 38 may be axially located between the gearbox assembly 18 and the stator 24. The gearbox fluid manifold assembly 38 may receive fluid traveling along the stator fluid passage 26 from the end cap fluid manifold assembly 42 and pass the fluid through the end turns 32 near the gearbox fluid manifold assembly 38. The gearbox fluid manifold assembly 38 may cause the received fluid to flow closely 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 arranged to closely conform to the shape of the end turns 32 so as to cause the fluid to flow in close proximity to or over the end turns 32. In this embodiment, the end turns 32 may be shaped such that at least a portion of the end turns 32 may extend in a direction that is not parallel to the shaft rotation axis (x). That is, during stator winding, the windings 30 may be positioned in the stator slots 28 such that the end turns 32 extend substantially parallel to the shaft rotation axis (x). After winding, the end turns 32 may be shaped such that they are joined at an angle that is not parallel to the shaft rotation axis (x). With the joined end turns 32 in mind, the outer segmented guides 82 and the inner segmented guides 84 may initially exist in a multi-part assembly that is later joined at one or more locations using fasteners 92 as the guides 82, 84 are positioned within the gearbox fluid manifold assembly 38 to accommodate the shape of the end turns 32. The outer segmented guides 82 and the inner segmented guides 84 may each include a flange 94 that is angled or sloped to such an extent that the flanges 94 are substantially parallel to the end turns 32 and closely fit the surface of the end turns 32.

[0043] In one embodiment, the inner segmented guide 84' may be made of Fig.29 and Fig.30. In this embodiment, the inner segmented guide 84' may initially be formed from an annular length of tube. The end turns 32 may be positioned within the stator 24 such that they extend away from the radial face 40 of the stator 24 and substantially parallel to the shaft rotation axis (x) during assembly. The inner segmented guide 84' may be positioned concentrically relative to the end turns 32. A tool including a mandrel 102 and a fixture 104 may be used to form 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' so that the shape closely fits the end turns 32. The mandrel 102 may be a cylindrical column having an outer shape that conforms to the desired shape of the inner segmented guide 84'. The fixture 104 may be in the form of a shape that also conforms to 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 fixture 104 can be radially moved relative to the shaft rotation axis (x) toward the outer surface of the guide 84', so that the mandrel 102 and the fixture 104 engage the guide 84' and form it in situ. The mandrel 102 and the fixture 104 can then be removed, and the inner segmented guide 84' can retain its shape. After the inner segmented guide 84 is formed, the end turns 32 can be mechanically bent or deformed so that they extend in a non-parallel orientation relative to the shaft rotation axis (x). The new orientation of the end turns 32 can be close to the inner segmented guide 84'.

[0044] The outer ring 86 may engage the inner segmented guide 84 at the distal end of the end turn 32 to help move the fluid around the end turn 32. The outer ring 86 may be formed of a solid continuous element that covers the end turn 32 and is coupled to the inner segmented guide 84 to encapsulate the end turn 32. The coupling may be achieved by a snap-fit ​​feature, wherein the aperture receives a stud that holds the elements together. The fluid may flow around the outer surface of the outer ring 86 between the flange 94 of the outer segmented guide 82 and the flange 94 of the inner segmented guide 84. The outer surface of the outer ring 86 may include a shaped outer surface 96 that is non-parallel to the axis of shaft rotation (x) over a certain length and parallel to the axis (x) over a portion. The inner ring 88 may be placed against the shaped outer surface 96 of the outer ring 86 and held in place by a plurality of studs 98 extending from the gearbox assembly 18. The gap between the contoured outer surface 96 of the outer ring and the surface of the inner ring 88 facing the outer ring 86 may direct the fluid to the fluid outlet holes 100 in the gearbox assembly 18 to direct the fluid to the gears within the assembly 18 .

[0045] It should be understood that the foregoing is a description of one or more embodiments of the present invention. The present invention is not limited to the specific embodiments disclosed herein, but is limited only by the appended claims. In addition, the statements contained in the foregoing description relate to specific embodiments and should not be interpreted as limitations on the definition of the terms used in the scope of the present invention or the claims, unless the terms or phrases are clearly defined above. Various other embodiments and various changes and modifications to the disclosed embodiments will be apparent to those skilled in the art. All these other embodiments, changes and modifications are intended to fall within the scope of the appended claims.

[0046] As used in this specification and claims, the terms "for example," "such as," and "etc." and the verbs "include," "have," "comprise," and other verb forms thereof, when used in conjunction with a list of one or more components or other items, should be interpreted as open-ended, meaning that the list should not be considered to exclude other additional components or items. Other terms should be interpreted using their broadest reasonable meaning unless they are used in a context that requires a different interpretation.

Claims

1. A cooling assembly for an electric drive system in a battery electric vehicle, comprising: An end cap fluid manifold assembly configured to be coupled to a radial face of a stator of a rotating electrical machine having: 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 end turns 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, is configured to receive a fluid and convey the fluid over the end turns.

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

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

4. The cooling assembly of claim 1, wherein the end cap fluid manifold assembly is concentrically positioned relative to the output shaft of the rotating electric 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 in the inner panel, the corresponding receiving portion radially positioning the outer panel fluid guide relative to the inner panel fluid guide.

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

8. A cooling assembly for an electric drive system in a battery electric vehicle, comprising: A gearbox fluid manifold assembly configured to be coupled to a radial face of a stator of a rotating electrical machine having: an outer segmented guide including a flange forming a portion of the fluid passageway and a plurality of segments connected at one or more circumferential locations; an inner segmented guide including a flange forming another portion of the fluid passage and a plurality of segments connected at one or more circumferential locations such that 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 passage; as well as A retaining ring axially constrains the inner ring relative to the end cap fluid manifold assembly.

9. The cooling assembly of claim 8, wherein the gearbox fluid manifold assembly is located between a stator and a gearbox assembly of the rotary electric machine.

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

11. The cooling assembly of claim 8, wherein the gearbox fluid manifold assembly is concentrically positioned relative to an output shaft of the rotary electric machine.

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

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 segment guide is a unitary structure and is formed in-situ.

15. A cooling assembly for an electric drive system in a battery electric vehicle, comprising: A gearbox fluid manifold assembly configured to be coupled to a radial face of a stator of a rotating electrical machine having: an outer plate having an outer plate fluid guide; an inner plate having an inner plate fluid guide and an end turn receiving portion, the end turn receiving portion abutting end turns of a stator winding in the rotating electric machine; a fluid passage formed between the outer plate fluid guide and the inner plate fluid guide, configured to receive a fluid and convey the fluid over the end turns, wherein the fluid passage is in fluid communication with a stator fluid passage in the stator; An end cap fluid manifold assembly coupled to another radial face of the stator of the rotating electrical machine has: an outer segment guide including a flange forming a portion of a fluid passage and a plurality of segments connected at one or more circumferential locations, wherein the fluid passage receives fluid from the stator fluid passage; an inner segmented guide including a flange forming another portion of the fluid passage and a plurality of segments connected at one or more circumferential locations such that 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 end turns of the rotating electrical machine; an inner ring coupled to the outer ring and forming a portion of the fluid passage; as well as A retaining ring axially constrains the inner ring relative to the end cap fluid manifold assembly.

Images