e-Motor connection with phase bar cooling and compliant internal support in the junction box

Abstract

An e-motor connection device for connecting power electronics of an electric or hybrid electric vehicle to an e-motor. The e-motor connection device includes a junction box configured to extend from the power electronics to the e-motor and a phase bar extending into the junction box and electrically connecting the power electronics to the e-motor. A first access cover is removably connected to the junction box and configured to provide access for connecting the phase bar to the e-motor, and a second access cover provides similar access for connecting the phase bar to the power electronics. To prevent overheating, the first access cover includes a cooling fluid channel having a cooling fluid inlet configured to be connected to a cooling fluid source and a cooling fluid outlet configured to be connected to a cooling fluid return.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Non-Provisional Application No. 17 / 487,016, filed September 28, 2021, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to e-motors (electric motors) used in electric or hybrid electric vehicles, and more specifically to phase bars used to connect the power electronics to the e-motor, which extend through a junction box between the power electronics and the e-motor. [Background technology]

[0003] In electric and hybrid electric vehicles, power electronics must be connected to the e-motor to deliver the required current. One known method of connecting the power electronics to the e-motor is to use phase bars or phase leads that extend through a junction box. However, depending on the current load, the phase bars, as well as the bolted connections to the e-motor, can overheat.

[0004] Additionally, the phase bars need to be securely held within the junction box to avoid vibration over a wide range of tolerances that can be affected by heat as well as other factors. Summary of the Invention [Means for solving the problem]

[0005] In one aspect, an e-motor connection device for connecting power electronics of an electric or hybrid electric vehicle to an e-motor is provided. The e-motor connection device includes a junction box configured to extend from the power electronics to the e-motor and phase bars extending into the junction box and adapted to electrically connect the power electronics to the e-motor. A first access cover is removably connected to the junction box and configured to provide access for connecting the phase bars to the e-motor, and a second access cover is removably connected to the power electronics and configured to provide access for connecting the phase bars to the power electronics. To prevent overheating, the first access cover includes a cooling fluid channel having a cooling fluid inlet configured to be connected to a cooling fluid source and a cooling fluid outlet configured to be connected to a cooling fluid return.

[0006] In one device form, the first access cover includes a bottom surface configured to contact a potting material surrounding a connection portion of the e-motor to which the phase bar is electrically connected to provide cooling.

[0007] In one embodiment, the cooling fluid channel has a linear path, with the cooling fluid inlet and cooling fluid outlet located on opposite sides of the first access cover. Alternatively, in another embodiment, the cooling fluid channel can have a non-linear or curved path. In one device configuration, the curved path is arranged such that the cooling fluid inlet and cooling fluid outlet are located on the same side of the first access cover.

[0008] In another aspect, the junction box includes a first housing portion and a second housing portion configured to be connected to each other in an assembled position. A first insulating retainer is provided and is configured to receive a phase bar. A second insulating retainer is also provided, and the second insulating retainer is configured to be disposed on the first insulating retainer such that the phase bar is held between the first insulating retainer and the second insulating retainer. An elastic tab is disposed on at least one of the first insulating retainer or the second insulating retainer, and the elastic tab is configured to contact an inner surface of at least one of the first housing portion or the second housing portion, and the elastic tab is further configured to generate a preload that presses the first insulating retainer and the second insulating retainer toward each other and against the phase bar when the first housing portion and the second housing portion are connected to each other in the assembled position.

[0009] In one embodiment, the elastic tabs are located on each of the first insulating retainer and the second insulating retainer.

[0010] In one device aspect, the first insulating retainer includes channels in which the phase bars are located and that insulate the phase bars from each other. Additionally, the second insulating retainer includes clamp protrusions that are aligned with the channels in the first insulating retainer for clamping against the phase bars.

[0011] In one embodiment, at least one of the first insulating retainer or the second insulating retainer includes alignment protrusions, and the other of the first insulating retainer or the second insulating retainer includes corresponding alignment receptacles for receiving the alignment protrusions.

[0012] The elastic tabs are configured to compensate for a total tolerance accumulation of 4 mm and apply a preload that presses the first insulating retainer and the second insulating retainer toward each other and against the phase bar. Thereby, movement of the phase bar due to vibration is prevented.

[0013] In one embodiment, the first insulating retainer and the second insulating retainer are formed of a glass-filled polymer, where the glass can be 10-50% by weight of the glass-filled polymer, and the polymer can be PPS.

[0014] In one embodiment, the joint may include a seal on its upper housing to prevent water ingress when bolted to the power electronics.

[0015] In another aspect, an electric vehicle drive for a hybrid-electric or electric vehicle is provided, including an e-motor including a stator and a rotor, and a transmission including a torque converter, the rotor being connectable to the torque converter. Power electronics configured to provide power to the e-motor are provided. An e-motor connection device configured to connect the power electronics to the e-motor is also provided and can include one or more of the features described above.

[0016] It should be noted that various of the above features can be used alone or in combination with one another.

[0017] The foregoing summary, as well as the following detailed description, will be better understood when read in conjunction with the accompanying drawings, which illustrate preferred embodiments of the present disclosure. [Brief description of the drawings]

[0018] [Figure 1] 1 is a partial cross-sectional schematic diagram illustrating an electric vehicle drive including an e-motor, power electronics, a transmission connected to the e-motor, and an e-motor connection device connecting the power electronics to the e-motor. [Diagram 2] e) An enlarged cross-sectional view of the motor connection device. [Diagram 3] FIG. 10 is a top view showing an access cover for an e-motor connection device including cooling fluid channels. [Figure 4]Top view of an alternative embodiment of an access cover for an e - motor connection device, including alternative cooling fluid channels. [Figure 5] Partial cross - sectional side view showing a junction box for an e - motor connection device including a pre - loaded retainer configuration for holding a phase bar in a predetermined position. [Figure 6] An enlarged view of the device configuration shown in FIG. 5, showing elastic tabs positioned on a first insulating retainer and a second insulating retainer that hold a phase bar. [Figure 7] Perspective view showing an embodiment of a first insulating retainer. [Figure 8] Perspective view showing an embodiment of a second insulating retainer adapted to be assembled with the first insulating retainer shown in FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

[0019] In the following description, specific terms are used for convenience only and are not limiting. The terms “inwardly” and “outwardly” refer to the direction towards and away from the parts referred to in the drawings. References to a list of items cited as “at least one of a or b” (where a and b represent the listed items) mean either any single one of the items a or b, or a combination of a and b. This applies equally to lists of three or more items, including individual items of the list or combinations thereof. The terms “about” and “approximately” include ± 10% of the indicated value unless otherwise stated. The terms include the words specifically described above, their derivatives, and similar significant words.

[0020] Referring to FIG. 1 , an electric vehicle or hybrid-electric vehicle drive (collectively, electric vehicle drive) arrangement 10 is shown somewhat diagrammatically. The electric vehicle drive arrangement 10 includes an e-motor 12 along with power electronics 11 configured to provide power to the e-motor 12. The e-motor 12 includes a stator 15 and a rotor 16 rotatable relative to the stator 15. The e-motor is configured to be integrated with or drivingly engaged to a transmission including a torque converter 18, with the rotor 16 selectively connectable to the torque converter 18. While this arrangement is shown in the context of a hybrid-electric drive for an automobile, those skilled in the art will understand that it can be used in the context of an electric vehicle, with the rotor connected to a transmission or further portion of the vehicle driveline, possibly without the use of a torque converter or transmission.

[0021] 1 and 2, an e-motor connection apparatus 20 for connecting the power electronics 11 to the e-motor 12 is also shown. The e-motor connection apparatus 20 includes a junction box 22 configured to extend from the power electronics 11 to the e-motor 12. Phase bars 30 extend into the junction box 22 and are adapted to electrically connect the power electronics 11 to the e-motor 12. This is preferably accomplished via bolted connections 17 (shown in FIG. 1) between the phase bars 30 and connections at the e-motor 12, along with additional bolted connections 19 (shown in FIG. 1) between the phase bars 30 and the power electronics 11. While the side views shown in FIGS. 1 and 2 show only one of the phase bars 30, one skilled in the art will understand that there are three phase bars, preferably made from copper or another conductive material, extending between the power electronics 11 and the e-motor 12. These are generally spaced apart from one another and held in isolation within the junction box 22 by, for example, a first insulating returner and a second insulating returner, discussed below in connection with Figures 5-8.

[0022] 1 , first access cover 40 is removably connected to junction box 22 and is configured to provide access for connecting phase bars 30 to e-motor 12, for example, by installing bolts used in connection with bolted connections 17. Additionally, second access cover 50 is removably connected to power electronics 11 and is configured to provide access for connecting phase bars 30 to power electronics 11, for example, using bolted connections 19. While bolted connections are shown, one skilled in the art will recognize that other types of connections may be utilized.

[0023] As shown in FIGS. 2-4 , to prevent overheating of the phase bars and their connections to the e-motor 12, the first access cover 40 includes a cooling fluid channel 42 having a cooling fluid inlet 44 configured to be connected to a cooling fluid source and a cooling fluid outlet 46 configured to be connected to a cooling fluid return. Preferably, the first access cover 40 includes a bottom surface 48 configured to contact a potting material 13, which may be made of silicone or another electrically insulating material, that surrounds the connection portion 14 of the e-motor 12 (shown in FIG. 2 ) to which the phase bars 30 are electrically connected. The first access cover 40 is preferably made of a metallic material such as aluminum. However, it may also be made of a thermally conductive polymer material.

[0024] As shown in Figure 3, cooling fluid channels 42 in one embodiment have a linear path 43, with cooling fluid inlets 44 and cooling fluid outlets 46 located on opposite sides of first access cover 40. In an alternative embodiment, as shown in Figure 4, cooling fluid channels 42 in first access cover 40 have a curved path 43'. Here, in one configuration, curved path 43' is arranged such that cooling fluid inlets 44 and cooling fluid outlets 46 are located on the same side of first access cover 40. However, they can be located on adjacent sides depending on the particular application.

[0025] The coolant inlet 44 and the coolant outlet 46 may be connected to an engine coolant system using known fluid connectors. Alternatively, they may be connected to a transmission or other cooling system.

[0026] Referring now to FIGS. 5-8, in one embodiment, the junction box 22 includes a first housing portion 24 and a second housing portion 26 configured to be connected to each other in an assembled position. As shown in FIGS. 5 and 6, a gasket 28 can be provided between the first housing portion 24 and the second housing portion 26 to prevent the ingress of moisture or debris.

[0027] To prevent the phase bar 30 from vibrating during use, a first insulating retainer 60 is located within the junction box 22 and is configured to receive the phase bar 30. As shown in FIG. 7, the first insulating retainer 60 is configured to have three spaces for receiving the three phase bars 30. In addition, a second insulating retainer 70 is configured to be disposed on the first insulating retainer 60 such that the phase bar 30 is held between the first insulating retainer 60 and the second insulating retainer 70 within the junction box 22. The first insulating retainer 60 and the second insulating retainer 70 are formed from an insulating material having elastic properties, and more preferably, are formed from a glass-filled polymer material. In one embodiment, the glass is 5-50 wt% of the glass-filled polymer and the polymer is PPS.

[0028] To prevent vibration and compensate for any thermal-induced expansion of the tolerance accumulation and the phase bar 30 or the junction box 22, elastic tabs 62, 72, as shown in detail in FIGS. 6-8, are located on at least one of the first insulating retainer 60 or the second insulating retainer 70, preferably on both of the insulating retainers 60, 70. The elastic tabs 62, 72 are configured to contact the respective inner surfaces 25, 27 of at least one of the first housing portion 24 and the second housing portion 26 of the second housing portion 26, preferably both of the first housing portion 24 and the second housing portion 26. The elastic tabs 62, 72 are configured to generate a preload that presses the first insulating retainer 60 and the second insulating retainer 70 towards each other and against the phase bar 30 when the first housing portion 24 and the second housing portion 26 are connected together in the assembled position, for example, using screws 29 around the junction box 22, and one example of which is shown in FIG. 5.

[0029] The elastic tabs 62, 72 are preferably designed to provide a minimum interference of 0.5 mm when the junction box 22 is assembled to provide the preload. In a preferred device configuration, the elastic tabs 62, 72 are configured to compensate for an accumulated tolerance of 4 mm while still applying a preload that presses the first insulating retainer 60 and the second insulating retainer 70 towards each other and against the phase bar 30.

[0030] Referring to FIGS. 7 and 8, to securely hold the phase bar 30 in a predetermined position and to prevent the phase bars 30 from contacting each other or the junction box, as shown in FIG. 7, the first insulating retainer 60 includes a channel 64 in which the phase bar 30 is positioned and which insulates the phase bars 30 from each other. As shown in FIG. 8, the second insulating retainer 70 includes a clamp protrusion 74 that is aligned with the channel 64 in the first insulating retainer 60, and the clamp protrusion 74 clamps the phase bar 30 when the first housing portion 24 and the second housing portion 26 of the junction box 22 are connected to each other in the assembled position, as shown in FIG. 5. Thereby, the clamp protrusion 74 presses the phase bar 30 to securely hold the phase bar 30 within the channel 64.

[0031] To enable easier alignment of the first insulating retainer 60 and the second insulating retainer 70 with each other, preferably, at least one of the first insulating retainer or the second insulating retainer includes an alignment protrusion 76, and the other of the first insulating retainer 60 or the second insulating retainer 70 includes a corresponding alignment portion, i.e., a receptacle 66, that receives the alignment protrusion 76. In the embodiment illustrated in FIGS. 7 and 8, there are two alignment protrusions 76 on the second insulating retainer 70 and two corresponding alignment receptacles 66 on the first insulating retainer 60. However, the number and position of these alignment protrusions 76 and receptacles 66 can be changed according to a particular application.

[0032] The elastic tabs 62, 72 generate a preload based on their inherent elastic resilience and based on the configuration in which the elastic tabs 62, 72 extend beyond the respective outer surfaces 68, 78 of the first insulating retainer 60 or the second insulating retainer 70 by a distance of about 0.5 mm, more preferably 1.0 mm, in the unmounted state, although the exact configuration can be adjusted for a particular application. For example, to compensate for a cumulative tolerance of 4 mm, the elastic tabs 62, 72 extend beyond the respective outer surfaces 68, 78 by at least about 2 mm each.

[0033] Regarding the electric vehicle drive unit 10, as discussed above, the electric vehicle drive unit 10 also includes an e - motor connection device 20 that includes one or more of the features described herein.

[0034] Using this device configuration, overheating of the phase bar connection part is prevented, and vibration of the phase bar 30 in the junction box 22 of the e - motor connection device 20 is also effectively prevented.

[0035] Thus, while the presently preferred embodiments have been described in detail, it should be understood that many physical changes can be made without changing the concepts of the invention and the principles embodied therein, and that some of these are only illustrated in the detailed description of the invention, and will be apparent to those skilled in the art. Also, numerous embodiments incorporating only some of the preferred embodiments are possible, and it should be understood that with respect to these parts, the concepts and principles of the invention embodied in the embodiments are not changed. Therefore, this embodiment and optional configurations should be regarded as illustrative and / or exemplary in all respects and not limiting, and the scope of the invention is indicated by the appended claims rather than the foregoing description, and accordingly, all alternative embodiments and modifications to this embodiment that fall within the meaning and scope of the equivalents of the claims should be included within the scope of the claims.

Explanation of Reference Numerals

[0036] 10 Electric vehicle drive unit 11 Power electronics 12 e - motor 13 Potting material 14 Connection part 15 Stator 16 Rotor 17 Bolt connection part 18 Torque converter 19 Bolt connection part 20 Connection device 22 Junction box 24 First housing part 25 24 inner surface 26 Second housing part 27 26 inner surface 28 Gasket 30 Phase Bar 40 First access cover 42 Cooling fluid channels 43 Linear Path 43' curved path 44 Cooling fluid inlet 46 Cooling fluid outlet 48 Bottom surface 50 Second Access Cover 60 First insulating retainer 62 Elastic Tab 64 channels 66 Alignment Receptacle 68 60 outer surface 70 Second insulating retainer 74 Clamp protrusion 76 Alignment protrusion 78 70 outer surface

Claims

1. An e-motor connection device for connecting the power electronics of an electric vehicle or a hybrid electric vehicle to an e-motor, the e-motor connection device comprising: A junction box configured to extend from the power electronics to the e-motor; A phase bar extending into the junction box and adapted to electrically connect the power electronics to the e-motor; A first access cover removably connected to the junction box and configured to provide access to a first connection portion for connecting the phase bar to the e-motor; A second access cover removably connected to the power electronics and configured to provide access to a second connection portion for connecting the phase bar to the power electronics, The first access cover includes a cooling fluid channel having a cooling fluid inlet configured to be connected to a cooling fluid source and a cooling fluid outlet configured to be connected to a cooling fluid return portion, the e-motor connection device.

2. The e-motor connection device according to claim 1, wherein the first access cover includes a bottom surface configured to contact a potting material surrounding a connection portion of the e-motor to which the phase bar is electrically connected.

3. The e-motor connection device according to claim 1, wherein the cooling fluid channel has a linear path, and the cooling fluid inlet and the cooling fluid outlet are located on both sides of the first access cover.

4. The e-motor connection device according to claim 1, wherein the cooling fluid channel has a curved path.

5. The e-motor connection device according to claim 4, wherein the curved path is arranged such that the cooling fluid inlet and the cooling fluid outlet are located on the same side of the first access cover.

6. The junction box includes a first housing portion and a second housing portion configured to be connected to each other in an assembled position, A first insulating retainer configured to receive the phase bar; A second insulating retainer configured to be disposed on the first insulating retainer such that the phase bar is held between the first insulating retainer and the second insulating retainer; An elastic tab positioned on at least one of the first insulating retainer or the second insulating retainer, the elastic tab being configured to contact an inner surface of at least one of the first housing portion or the second housing portion, and the elastic tab being configured to generate a preload that presses the first insulating retainer and the second insulating retainer toward each other and against the phase bar when the first housing portion and the second housing portion are connected to each other at the assembly position. An elastic tab, further comprising the e-motor connection device according to claim 1.

7. The e-motor connection device according to claim 6, wherein the elastic tab is located on each of the first insulating retainer and the second insulating retainer.

8. The e-motor connection device according to claim 6, wherein the first insulating retainer includes a channel in which the phase bar is located and that insulates the phase bars from each other.

9. The e-motor connection device according to claim 8, wherein the second insulating retainer includes a clamp protrusion aligned with the channel in the first insulating retainer for clamping against the phase bar.

10. The e-motor connection device according to claim 9, wherein at least one of the first insulating retainer or the second insulating retainer includes an alignment protrusion, and the other of the first insulating retainer or the second insulating retainer includes a corresponding alignment receptacle for receiving the alignment protrusion.

11. The e-motor connection device according to claim 6, wherein the elastic tab is configured to compensate for a total allowable error accumulation of 4 mm and apply a load that presses the first insulating retainer and the second insulating retainer toward each other and against the phase bar.

12. The e-motor connection device according to claim 6, wherein the first insulating retainer and the second insulating retainer are formed from a glass-filled polymer.

13. The e-motor connection device according to claim 12, wherein the glass is 10 to 50% by weight of the glass-filled polymer, and the polymer is PPS.

14. An electric vehicle drive unit, An e-motor including a stator and a rotor, A transmission including a torque converter, wherein the rotor is connectable to the torque converter. A transmission, Power electronics configured to supply power to the e-motor, An e-motor connection device configured to connect the power electronics to the e-motor, the e-motor connection device comprising: A junction box extending from the power electronics to the e-motor, A phase bar extending into the junction box and electrically connected to the power electronics and the e-motor, A first access cover removably connected to the junction box and configured to provide access to a first connection portion for connecting the phase bar to the e-motor, A second access cover removably connected to the power electronics and configured to provide access to a second connection portion for connecting the phase bar to the power electronics, The first access cover includes a cooling fluid channel having a cooling fluid inlet configured to be connected to a cooling fluid source and a cooling fluid outlet configured to be connected to a cooling fluid return portion, and an e-motor connection device. An electric vehicle drive unit comprising.

15. The electric vehicle drive unit according to claim 14, wherein the first access cover includes a bottom surface configured to contact a potting material surrounding a connection portion of the e-motor to which the phase bar is electrically connected.

16. The electric vehicle drive unit according to claim 14, wherein the cooling fluid channel has a linear path, and the cooling fluid inlet and the cooling fluid outlet are disposed on both sides of the first access cover.

17. The electric vehicle drive unit according to claim 14, wherein the cooling fluid channel has a curved path.

18. The electric vehicle drive unit according to claim 17, wherein the curved path is arranged such that the cooling fluid inlet and the cooling fluid outlet are located on the same side of the first access cover.

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