Vehicle electric drive assemblies

Abstract

Aspects of the present invention relate to a vehicle (10) having first and second electric drive assemblies 12, 14), the first electric drive assembly (12) comprising: a first electric drive unit (16)

Description

TECHNICAL FIELD The present disclosure relates to a vehicle electric drive assemblies. Aspects of the invention relate to a vehicle having first and second electric device assemblies and a method of assembling first and second electric drive assemblies. BACKGROUND Within an electric vehicle an electric drive assembly comprises an electric drive unit (an electric motor) and an inverter which is electrically coupled to the electric drive unit by a busbar assembly. The electric drive unit generates power to propel the vehicle. The inverter is configured to convert direct current from the vehicle’s battery to alternative current to power the electric drive unit. Due to differing packaging requirements between different electric vehicles and even differing packaging requirements at different locations within a particular electric vehicle, there is often a need to install differently dimensioned inverters to enable the electric drive assembly fits within the available space. This leads to part proliferation across a vehicle range. It is also noted that it is expensive to design differently dimensioned inverters. It is an aim of the present invention to address one or more of the disadvantages associated with the prior art. SUMMARY OF THE INVENTION Aspects and embodiments of the invention provide a vehicle and a method of assembling first and second electric drive assemblies within a vehicle as claimed in the appended claims According to an aspect of the present invention there is provided a vehicle having first and second electric drive assemblies, the first electric drive assembly comprising: a first electric drive unit having a first drive connector; a first inverter having a first power electronics connector, the first drive connector having a first offset from the first power electronics connector; a first busbar assembly configured in dependence with the first offset, a first end of the first busbar assembly being mechanically and electrically coupled to the first drive connector and a second end of the first busbar assembly being mechanically and electrically coupled to the first power electronics connector; and the second electric drive assembly comprising: a second electric drive unit having a second drive connector; a second inverter having a second power electronics connector, the second drive connector having a second offset from the second power electronics connector; a second busbar assembly configured in dependence with the second offset, a first end of the second busbar assembly being mechanically and electrically coupled to the second drive connector and a second end of the second busbar assembly being mechanically and electrically coupled to the second power electronics connector; wherein the first offset is different to the second offset and wherein the first inverter shares a common inverter design with the second inverter. The first electric drive unit may share a common electric drive unit design with the second electric drive unit. Sharing a common design means that, at least prior to installation, electric drive units and inverters sharing the same design” are interchangeable with one another, at least insofar as their packaging is concerned. It may be that they are different in other respects, such as in their electrical configuration, but equally they may be identical in all respects. The first electric drive assembly may be mounted on a first axle and the second electric drive assembly may be mounted on a second axle. The first electric drive assembly may be mounted on a first axle and may be configured to drive a first wheel on the first axle and the second electric drive assembly may be mounted on the first axle and configured to drive a second wheel on the first axle. Each busbar assembly may comprise three busbar members. Each busbar member may comprise a rigid, planar metal bar. Each busbar member may have a kink in the plane of the busbar to accommodate the offset of the inverter with respect to the electric drive unit. Each busbar member may be formed with a bend out of the plane of the bus bar at one or both ends of the busbar to form connection tabs for the drive connector and / or power electronics connector. Each busbar member may formed with one or more bends out of the plane of the bus bar intermediate its ends to accommodate an offset out of said plane of the inverter with respect to the electric drive unit. Each busbar member may lie in a common plane at a region intermediate its ends, said region being at a location coinciding with a slot in a housing of the inverter through which the busbar members pass, the slot being of a length greaterthan the width of the busbars in said region, whereby busbars having a different offset may be received in the slot in different positions along the slot. Each busbar member in the first busbar assembly may be shaped differently to each busbar member in the second busbar assembly, the shape of the busbar members being defined in dependence on either the first or second offset. The vehicle may comprise a third electric drive assembly, the third electric drive assembly comprising: a third electric drive unit having a third drive connector; a third inverter having a third power electronics connector, the third drive connector having a third offset from the third power electronics connector; a third busbar assembly configured in dependence with the third offset, a first end of the third busbar assembly being mechanically and electrically coupled to the third drive connector and a second end of the third busbar assembly being mechanically and electrically coupled to the third power electronics connector; wherein the first, second and third offsets may all be different and wherein the first, second and third inverters may share a common design. According to an aspect of the present invention there is provided a method of assembling first and second electric drive assemblies within a vehicle, the first electric drive assembly comprising: installing a first electric drive unit having a first drive connector; installing a first inverter having a first power electronics connector, the first drive connector having a first offset from the first power electronics connector; installing a second electric drive unit having a second drive connector; installing a second inverter having a second power electronics connector, the second drive connector having a second offset from the second power electronics connector, wherein the first offset is different to the second offset; selecting a first busbar assembly in dependence on the first offset; mechanically and electrically coupling a first end of the first busbar assembly being to the first drive connector and mechanically and electrically coupling a second end of the first busbar assembly to the first power electronics connector; and selecting a second busbar assembly in dependence on the second offset; mechanically and electrically coupling a first end of the second busbar assembly to the second drive connector and mechanically and electrically coupling a second end of the second busbar assembly to the second power electronics connector; wherein the first inverter shares a common design with the second inverter. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in anyway and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows a vehicle having first and second electric drive assemblies in accordance with an embodiment of the present invention; Figure 2 shows a perspective view of a first electric drive assembly in accordance with an embodiment of the present invention; Figure 3 shows a front view of the assembly of Figure 2; and Figure 4 shows a perspective view of a second electric drive assembly in accordance with an embodiment of the present invention; Figure 5 shows a front view of the assembly of Figure 4; Figure 6 shows a method of assembling first and second electric drive assemblies within a vehicle. DETAILED DESCRIPTION Figure 1 shows a vehicle 10 comprising a first electric drive assembly 12 and a second electric drive assembly 14. The first electric drive assembly 12 comprises a first electric drive unit 16 and a first inverter 18. The electric drive unit 16 and inverter 18 are mechanically and electrically coupled to each other via a first busbar assembly 20. The electric drive unit 16 is coupled to a first axle 22 in order to transmit a driving torque to the first axle 22. The second electric drive assembly 14 comprises a second electric drive unit 24 and a second inverter 26. The electric drive unit 24 and inverter 26 are mechanically and electrically coupled to each other via a second busbar assembly 28. The electric drive unit 24 is coupled to a second axle 30 in order to transmit a driving torque to the second axle 30. The first inverter 18 has a first offset 32 from the first electric drive unit 16. The second inverter 26 has a second offset 34 from the second electric drive unit 24. Figures 2 and 3 show a first electric drive assembly and Figures 4 and 5 show a second electric drive assembly. For the purposes of the following description the first electric drive assembly of Figures 2 and 3 is taken to correspond to the first electric drive assembly 12 of Figure 1 and the second electric drive assembly of Figures 4 and 5 is taken to correspond to the second electric drive assembly 14 of Figure 1. Figure 2 shows a perspective view of the first electric drive assembly 12 in accordance with an embodiment of the present invention. Figure 3 shows the same electric drive assembly from a front view. Figure 2 shows the first electric drive unit 16, first inverter 18 and first busbar assembly 20 of Figure 1. It can be seen from Figure 2 that the busbar assembly comprises three busbar members 40, 42, 44 in the form of rigid planar metal bars. The electric drive unit 16 comprises a first drive connector 46. The first inverter 18 comprises a first power electronics connector 48. The busbar assembly 20 is coupled at one end to the first drive connector 46 and at the other end to the first electronics connector 48 such that the electric drive unit 16 and inverter 18 are mechanically and electrically coupled to each other. It is noted that the first drive connector 46 comprises three connection points 50, 52, 54 for coupling to one end of the three busbar members 40, 42, 44 respectively. The first power electronics connector 48 comprises three connection points 56, 58, 60 for coupling to a second end of the three busbar members 40, 42, 44 respectively. Figure 3 shows the first electric drive assembly 12 of Figure 2 from a front view. Like numerals are used to denote like features between Figures 2 and 3. For clarity the busbar members and connection points on the first drive connector and first power connector are not labelled. However, it is understood that these are the same features in both Figures 2 and 3. As shown in Figure 3, the busbar assembly 20 enters the housing of the inverter 18 through a slot 62. The dotted lines extending from the centre point of the first drive connector 46 and from the centre of the first power connector 48 indicate a first offset 32 between the electric drive unit 16 and the inverter 18. Figure 4 shows a perspective view of a second electric drive assembly 14 in accordance with an embodiment of the present invention. Figure 5 shows the same electric drive assembly from a front view. Figure 4 shows the second electric drive unit 24, second inverter 26 and second busbar assembly 28 of Figure 1. It can be seen from Figure 4 that the busbar assembly comprises three busbar members 70, 72, 74 in the form of rigid planar metal bars. The second electric drive unit 24 comprises a second drive connector 76. The second inverter 26 comprises a second power electronics connector 78. The second busbar assembly 28 is coupled at one end to the second drive connector 76 and at the other end to the second electronics connector 78 such that the electric drive unit 24 and inverter 26 are mechanically and electrically coupled to each other. It is noted that the first drive connector 76 comprises three connection points 80, 82, 84 for coupling to one end of the three busbar members 70, 72, 74 respectively. The first power electronics connector 78 comprises three connection points 86, 88, 90 for coupling to a second end of the three busbar members 70, 72, 74 respectively. Figure 5 shows the first electric drive assembly 14 of Figure 4 from a front view. Like numerals are used to denote like features between Figures 4 and 5. For clarity the busbar members and connection points on the second drive connector and second power connector are not labelled. However, it is understood that these are the same features in both Figures 4 and 5. As shown in Figure 5, the busbar assembly 28 enters the housing of the inverter 26 through a slot 92. The dotted lines extending from the centre point of the second drive connector 76 and from the centre of the second power connector 78 indicate a second offset 34 between the electric drive unit 24 and the inverter 26. The first and second electricdrive assemblies 12,14 of embodiments ofthe present invention comprise a first busbar assembly 20 that is of a different configuration to a second busbar assembly 28. As a result, the first offset 32 (between the drive connector ofthe first electric drive unit and the power connector ofthe first inverter) is different to the second offset 34 (between the drive connector ofthe second electric drive unit and the power connector ofthe second inverter). As a result ofthe different configurations ofthe busbar assemblies 20, 28 it is possible for the first inverter 18 and the second inverter 26 to have a shared / common inverter design rather than requiring differently configured inverters to be installed in the vehicle. In other words differently configured busbar assemblies may be designed to allow an electric drive unit and an inverter to be installed in varying packaging environments / with respect to different space constraints. In Figure 1, the first electric drive unit 16 is shown on a first axle 22 and the second electric drive unit 24 is shown on a second axle 30. It is to be appreciated that in an alternative configuration, first electric drive assembly 12 may be mounted on the first axle 22 and is configured to drive a first wheel on the first axle and the second electric drive assembly 14 may be mounted on the same (first) axle 22 and configured to drive a second wheel on the first axle. Similarly, first electric drive assembly 12 may be mounted on the second axle 30 and is configured to drive a first wheel on the second axle and the second electric drive assembly 14 may be mounted on the same (second) axle 30 and configured to drive a second wheel on the second axle. The electric drive units 16, 24 may also share a common design to further reduce part proliferation within the vehicle. Although two electric drive assemblies 12, 14 are described above in Figures 1 to 5, it is noted that a vehicle may comprise a third electric drive assembly in which a third offset is defined between a third electric drive unit and a third inverter and wherein the first, second and third offsets are all different and the first, second and third inverters all share a common design. Similarly, a vehicle may comprise a fourth electric drive assembly which defines a fourth offset between a fourth electric drive unit and a fourth inverter and wherein all four offsets are different and all inverters share a common design. In Figures 2 to 5, there are three busbar members shown for each busbar assembly. It is to be appreciated however that depending on the vehicle configuration, electric drive unit design and / or inverter design there may be more or fewer busbar members in the busbar assembly. As is evident in Figures 2 to 5 each busbar member has a kink in the plane of the busbar to accommodate the offset of the inverter with respect to the electric drive unit. This aligns each busbar member from its connections 50,52,54 and 80,82,84 to the electric drive unit, which have each a specific first separation from each other, with its connections 56, 58, 60 and 86, 88, 90 to the power connectors of the inverter, which also have each a specific second separation from each other. Each busbar member is formed with a bend out of the plane of the bus bar at one end of the busbar to form the connection tabs 56, 58, 60 and 86, 88, 90 for the electronics connector. Such a bend is not required for tabs 50,52,54 and 80,82,84 for connection to the electric drive unit. These tabs lie in the plane of the busbar, but this may not be the case in different embodiments. In any event, each busbar member 40, 42, 44 and 70, 72, 74 otherwise lies in substantially the same plane in the present embodiment, but they could be formed with one or more bends out of the plane of the bus bar intermediate their ends to accommodate an offset (not shown), out of said plane, of the inverter with respect to the electric drive unit. At least in one region, however each busbar member 40, 42, 44 and 70, 72, 74 lies in a common plane at a region intermediate its ends. That region is at a location coinciding with the slot 62,92 in a housing of the inverter through which the busbar members pass. It is to be noted that the slot is of a length greater than the width of the busbars in said region, which is largely based on the separation of the connections 50,52,54 and 80,82,84 to the electric drive unit. The slot is longer than this so that busbars having a different offset (in that plane, may be received in the slot in different positions along the slot, as is evident from Figures 3 and 5. Figure 6 illustrates a method 600 according to an embodiment of the invention. The method 600 is a method of assembling first and second electric drive assemblies 12, 14 within a vehicle 10, such as the vehicle 10 illustrated in Figure 1. In step 602, a first electric drive unit 16 which has a first drive connector 46 is installed into the vehicle 10. A first inverter 18 is then installed in step 604, the inverter having a first power electronics connector 48. It is noted that the first drive connector 46 is offset (by a first offset 32) from the first power electronics connector 48. In step 606, a second electric drive unit 24 which has a second drive connector 76 is installed into the vehicle 10. A second inverter 26 is then installed in step 608, the second inverter having a second power electronics connector 78. It is noted that the second drive connector 76 is offset (by a second offset 34) from the second power electronics connector 78. The first inverter 18 and second inverter 26 share a common design. In step 610, a first busbar assembly 20 is selected in dependence on the first offset 32 and in step 612, a first end of the first busbar assembly 20 is mechanically and electrically coupled to the first drive connector 46 and, in step 614, a second end of the first busbar assembly 20 is mechanically and electrically coupled to the first power electronics connector 48. In step 616, a second busbar assembly 28 is selected in dependence on the second offset 34 and in step 618, a first end of the second busbar assembly 28 is mechanically and electrically coupled to the second drive connector 76 and, in step 620, a second end of the second busbar assembly 28 is mechanically and electrically coupled to the second power electronics connector 78. The illustration of a particular order to the blocks illustrated in FIG. 6 does not necessarily imply that there is a required or preferred order for the blocks and the order and arrangement of the blocks may be varied. Furthermore, it may be possible for some steps in the method to be omitted. It will be appreciated that various changes and modifications can be made to the present invention without departing from the scope of the present application.

Claims

1. A vehicle having first and second electric drive assemblies,the first electric drive assembly comprising:a first electric drive unit having a first drive connector;a first inverter having a first power electronics connector, the first drive connector having a first offset from the first power electronics connector;a first busbar assembly configured in dependence with the first offset, a first end of the first busbar assembly being mechanically and electrically coupled to the first drive connector and a second end of the first busbar assembly being mechanically and electrically coupled to the first power electronics connector; andthe second electric drive assembly comprising:a second electric drive unit having a second drive connector;a second inverter having a second power electronics connector, the second drive connector having a second offset from the second power electronics connector;a second busbar assembly configured in dependence with the second offset, a first end of the second busbar assembly being mechanically and electrically coupled to the second drive connector and a second end of the second busbar assembly being mechanically and electrically coupled to the second power electronics connector;wherein the first offset is different to the second offset and wherein the first inverter shares a common inverter design with the second inverter.

2. A vehicle as claimed in Claim 1, wherein the first electric drive unit shares a common electric drive unit design with the second electric drive unit.

3. A vehicle as claimed in Claim 1 or Claim 2, wherein the first electric drive assembly is mounted on a first axle and the second electric drive assembly is mounted on a second axle.

4. A vehicle as claimed in Claim 1 or Claim 2, wherein the first electric drive assembly is mounted on a first axle and is configured to drive a first wheel on the first axle and the second electric drive assembly is mounted on the first axle and configured to drive a second wheel on the first axle.

5. A vehicle as claimed in any preceding claim, wherein each busbar assembly comprises three busbar members.

6. A vehicle as claimed in Claim 5, wherein each busbar member comprises a rigid, planar metal bar.

7. A vehicle as claimed in Claim 6, wherein each busbar member has a kink in the plane of the busbarto accommodate the offset of the inverter with respect to the electric drive unit.

8. A vehicle as claimed in Claim 6 or 7, wherein each busbar member is formed with a bend out of the plane of the bus barat one or both ends of the busbar to form connection tabs for the drive connector and / or power electronics connector.

9. A vehicle as claimed in Claim 6, 7 or 8, wherein each busbar member is formed with one or more bends out of the plane of the bus bar intermediate its ends to accommodate an offset out of said plane of the inverter with respect to the electric drive unit.

10. A vehicle as claimed in any of Claims 6 to 9, wherein each busbar member lies in a common plane at a region intermediate its ends, said region being at a location coinciding with a slot in a housing of the inverter through which the busbar members pass, the slot being of a length greater than the width of the busbars in said region, whereby busbars having a different offset may be received in the slot in different positions along the slot.

11. A vehicle as claimed in any of Claims 5 to 10, wherein each busbar member in the first busbar assembly is shaped differently to each busbar member in the second busbar assembly, the shape of the busbar members being defined in dependence on either the first or second offset.

12. A vehicle as claimed in any preceding claim, comprising a third electric drive assembly, the third electric drive assembly comprising:a third electric drive unit having a third drive connector;a third inverter having a third power electronics connector, the third drive connector having a third offset from the third power electronics connector;a third busbar assembly configured in dependence with the third offset, a first end of the third busbar assembly being mechanically and electrically coupled to the third drive connector and a second end of the third busbar assembly being mechanically and electrically coupled to the third power electronics connector;wherein the first, second and third offsets are all different andwherein the first, second and third inverters share a common design.

13. A method of assembling first and second electric drive assemblies within a vehicle, the method comprising:installing a first electric drive unit having a first drive connector;installing a first inverter having a first power electronics connector, the first drive connector having a first offset from the first power electronics connector;installing a second electric drive unit having a second drive connector;installing a second inverter having a second power electronics connector, the second drive connector having a second offset from the second power electronics connector, wherein the first offset is different to the second offset;selecting a first busbar assembly in dependence on the first offset;mechanically and electrically coupling a first end of the first busbar assembly to the first drive connector and mechanically and electrically coupling a second end of the first busbar assembly to the first power electronics connector; andselecting a second busbar assembly in dependence on the second offset;5 mechanically and electrically coupling a first end of the second busbar assembly to the seconddrive connector and mechanically and electrically coupling a second end of the second busbar assembly to the second power electronics connector;wherein the first inverter shares a common design with the second inverter.10

Images