DRIVE UNIT FOR AN ELECTRIC VEHICLE

Abstract

A drive unit for an electric vehicle has at least one electric machine, a multi-speed transmission, and a distributor device. The rotor of each electric machine is connected to an associated input shaft of the multi-speed transmission. The multi-speed transmission is connected on the output side to the distributor device with different transmission ratios being selectable in the multi-speed transmission. In addition, a drive power introduced into the distributor device can be distributed to at least two outputs of the distributor device. In order to provide a compact drive unit for an electric vehicle with permanent all-wheel drive or selectable all-wheel drive, the distributor device can be used to provide a longitudinal distribution of the introduced drive power in that the outputs of the distributor device are each provided for coupling to a respective drive axle of the electric vehicle.

Claims

1-14. (canceled)

15. A drive unit (7; 58) for an electric vehicle (1) having drive axles (3, 41), the drive unit comprising: at least one electric machine (14, 15) having a rotor; a multi-speed transmission (16) having an input shaft and an output side; and a distributor device (17) having outputs; wherein the rotor (20, 21) of each at least one electric machine (14, 15) is connected to an associated input shaft (23, 24) of the multi-speed transmission (16), and the output side the multi-speed transmission (16) is connected to the distributor device (17); wherein different transmission ratios can be selected in the multi-speed transmission (16), wherein a drive power introduced into the distributor device (17) is distributable to at least two of the outputs (9, 10) of the distributor device (17) via the distributor device (17), and wherein the distributor device (17) is configured to provide a longitudinal distribution of the drive power introduced into the distributor device so that individual outputs (9, 10) of the distributor device (17) are provided for coupling to a respective drive axle (3, 4) of the electric vehicle (1).

16. The drive unit (7; 58) of claim 15, wherein the at least one electric machine (14, 15), the multi-speed transmission (16), and the distributor device (17) are accommodated together in a housing (22).

17. The drive unit (58) of claim 16, wherein the at least one electric machine (14, 15), the multi-speed transmission (16) and the distributor device (17) are arranged axially adjacently to one another.

18. The drive unit (7) of claim 1 or 2, wherein the at least one electric machine (14, 15), the multi-speed transmission (16), and the distributor device (17) are coaxially arranged, wherein the multi-speed transmission (16) and/or the distributor device (17) is axially in line with the at least one electric machine (14, 15) and radially inward of the at least one electric machine (14, 15).

19. The drive unit (7; 58) of claim 15, wherein the distributor device (17) comprises a differential transmission.

20. The drive unit (7; 58) of claim 19, wherein the differential transmission is configured as a bevel gear differential (43).

21. The drive unit (7; 58) of claim 19, wherein the differential transmission is configured as a planetary differential (52).

22. The drive unit (7; 58) of claim 15, wherein, in the distributor device (17), a first output (9) is permanently coupled to an input side of the distributor device (17), and a second output (10) is rigidly connectable to the first output (9) via a clutch (57).

23. The drive unit (7; 58) of claim 15, wherein the at least one electric machine includes a first electric machine (14) and a second electric machine (15), a rotor (20) of the first electric machine (14) being connected to a first input shaft (23) of the multi-speed transmission (16) and a rotor (21) of the second electric machine (15) being connected to a second input shaft (24) of the multi-speed transmission (16).

24. The drive unit (7; 58) of claim 15, wherein the multi-speed transmission (16) comprises a plurality of planetary gear sets (25, 26), each of the planetary gear sets having a first element (27, 28) in the form of a sun gear, a second element (29, 30) in the form of a planet web, and a third element (31, 32) in the form of a ring gear, wherein the multi-speed transmission (16) further comprises a plurality of shift elements (34-38), individual shift elements (34-38) configured for selective actuation to enable selecting from different transmission ratios between the associated input shaft (23, 24) and an output shaft.

25. The drive unit (7; 58) of claim 24, wherein: a second input shaft (24) is connected for conjoint rotation to the first element (27) of a first planetary gear set (25); the third element (31) of the first planetary gear set (25) is fixed; the second element (29) of the first planetary gear set (25) and the third element (32.) of a second planetary gear set (26) are connected to one another for conjoint rotation; an output shaft of the multi-speed transmission (16) is connected for conjoint rotation to the second element (30) of the second planetary gear set (26); a first input shaft (23) is connectable for conjoint rotation to the first element (28) of the second planetary gear set (26) via a first shift element (34) and can be brought into connection for conjoint rotation to the second input shaft (24) by means of a second shift element (35); the first element (28) of the second planetary gear set (26) can be fixed via a third shift element (36) and is connectable for conjoint rotation to the second input shaft (24) by means of a fourth shift element (37); and two of the first element, second element, and third element (28, 30, 32) of the second planetary gear set (26) can be brought into connection for conjoint rotation to one another via a fifth shift element (38).

26. The drive unit (7; 58) of claim 25, wherein the first shift element (34) and the second shift element (35) are combined to form a shift device (39), the shift device (39) having an actuating device (40) via which, on one hand the first shift element (34) is transferrable into an actuated state, and on another hand the second shift element (35) is transferrable into an actuated state.

27. The drive unit (7; 58) of claim 26, wherein the third shift element (36), the fourth shift element (37) and the fifth shift element (38) are combined to form a second shift device (41), the second shift device (41) having, an actuating device (42) via which a third shift element (36), the fourth shift element (37), or the fifth shift element (38) is transferrable in each case into an actuated state.

28. A drivetrain (2) for an electric vehicle (1), the drivetrain comprising a drive unit (7; 58) of claim 15.

29. The drivetrain (2) of claim 28, wherein at least one drivable front axle (5) is drivingly connected to a first output (9) of the distributor device (17) of the drive unit (7; 58) and at least one drivable rear axle (6) is drivingly connected to a second output (10) of the distributor device (17) of the drive unit (7; 58).

30. An electric vehicle comprising the drivetrain (2) of claim 28.

31. The electric vehicle of claim 30, configured as an off-road utility vehicle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Advantageous embodiments of the invention, which are explained below, are shown in the drawings, in which:

[0037] FIG. 1 shows a schematic representation of an electric vehicle according to a preferred embodiment of the invention;

[0038] FIG. 2 shows a side view of a drivetrain of the electric vehicle from FIG. 1;

[0039] FIG. 3 shows a schematic representation of a drive unit of the drivetrain from FIG. 2, according to a first possible embodiment of the invention;

[0040] FIGS. 4 to 6 show schematic views of possible embodiments of a distributor device of the drive unit from FIG. 3; and

[0041] FIG. 7 shows a schematic representation of a drive unit according to a second embodiment of the invention.

DETAILED DESCRIPTION

[0042] FIG. 1 shows a schematic view of an electric vehicle 1, which is in particular an off-road utility vehicle. The electric vehicle 1 in this case has a drivetrain 2, which is equipped with two drive axles 3 and 4. The drive axle 3 in this case is a steerable front axle 5, and the drive axle 4 is a non-steerable rear axle 6. In this respect, the electric vehicle 1 is equipped with a permanent or selectable all-wheel drive.

[0043] Within the drivetrain 2, the two drive axles 3 and 4 can be driven via a drive unit 7, which is placed in the longitudinal direction of the electric vehicle 1 between the drive axles 3 and 4. Specifically, an axle differential 8 of the drive axle 3 is connected here to an output 9 of the drive unit 7, and the drive unit 7 is furthermore connected to an axle differential 11 of the drive axle 4 at an output 10. As can be seen in the side view of the drivetrain 2 in FIG. 2, the connection of each output 9 and 10 to the corresponding axle differentials 8 and 11 respectively of the corresponding drive axles 3 and 4 respectively is established via an intermediate cardan shaft 12 and 13 respectively.

[0044] FIG. 3 also shows a schematic individual representation of the drive unit 7, the drive unit 7 being formed here in accordance with a first embodiment of the invention. In this case, the drive unit 7 comprises a first electric machine 14, a second electric machine 15, a multi-speed transmission 16 and a distributor device 17. The electric machines 14 and 15 each have a stator 18 and 19, respectively, and a rotor 20 and 21, respectively, the stators 18 and 19 of the electric machines 14 and 15, respectively, being permanently fixed to a housing 22 of the drive unit 7. On the one hand, each of the individual electric machines 14 and 15 can be operated in generator operation, in which it generates current when the corresponding rotor 20 or 21 is driven. On the other hand, however, each individual electric machine 14 or 15 can also be operated in electric motor operation, in which case a drive movement of the particular rotor 20 or 21 is produced when an appropriate power supply is provided.

[0045] The rotor 20 of the first electric machine 14 is connected for conjoint rotation to a first input shaft 23 of the multi-speed transmission 16, the multi-speed transmission 16 also having a second input shaft 24 which is permanently connected for conjoint rotation to the rotor 21 of the second electric machine 15. In addition, the multi-speed transmission 16 has two planetary gear sets 25 and 26, each of which is composed of a first element 27 and 28, respectively, a second element 29 and 30, respectively, and a third element 31 and 32, respectively.

[0046] Each first element 27 and 28 of each planetary gear set 25 and 26 respectively is a sun gear, while each second element 29 and 30 of each planetary gear set 25 and 26 respectively is a planet web. Finally, each third element 31 and 32 of each planetary gear set 25 and 26 respectively is a ring gear. In each planet web, at least one planet gear is rotatably mounted and is in meshing engagement with both the corresponding sun gear and the corresponding ring gear of the particular planet gear set 25 or 26. In this respect, the two planetary gear sets 25 and 26 are designed as simple planetary sets.

[0047] Alternatively, one or both planetary gear sets 25 and 26 could be designed as compound planetary gear sets, in which case, compared to the embodiment as a simple planetary gear set, each second element of each planetary gear set is to be formed by the corresponding ring gear and each third element of each planetary gear set is to be formed by the corresponding planet web. In this respect, in this case, a ring gear and planet web connection can be exchanged with each other, and furthermore a stationary transmission ratio of the particular planetary gear set is to be increased by one. In addition, in the case of an embodiment as a compound planetary gear set, at least one planetary gear pair would be rotatably mounted in the corresponding planet web, one planetary gear from the planetary gears of said planetary gear pair being in meshing engagement with the corresponding sun gear and one planetary gear being in meshing engagement with the corresponding ring gear, the planetary gears of the at least one planetary gear pair furthermore meshing with one another.

[0048] As can be seen in FIG. 3, the first element 27 of the first planetary gear set 25 is continuously connected for conjoint rotation to the second input shaft 24, while the second element 29 of the first planetary gear set 25 and the third element 32 of the second planetary gear set 26 are permanently connected for conjoint rotation to each other. Furthermore, the third element 31 of the first planetary gear set 25 is continuously fixed in that the third element 31 is permanently connected in a rotationally fixed manner to the housing 22 of the drive unit 7. In addition, the second element 30 of the second planetary gear set 20 is continuously connected for conjoint rotation to a drive shaft 33 of the distributor device 17, by means of which a drive power introduced at the drive shaft 33 is distributed or can be distributed to the two outputs 9 and 10. The drive shaft 33 of the distributor device 17 in this case also forms an output shaft of the multi-speed transmission 16.

[0049] The multi-speed transmission 16 also has a total of five shift elements 34 to 38, each of which are interlocking shift elements in the form of unsynchronized dog shift elements. In an actuated state, the first shift element 34 connects the first input shaft 23 and thus also the rotor 20 of the first electric machine 14 for conjoint rotation to the first element 28 of the second planetary gear set 26. By contrast, a closed state of the second shift element 35 results in a connection of the first input shaft 23 for conjoint rotation to the second input shaft 24, so that the two rotors 20 and 21 of the electric machines 14 and 15 thus also rotate at the same speed.

[0050] If, on the other hand, the third shift element 36 is brought into a closed state, the first element 28 of the second planetary gear set 26 is fixed to the housing 22 and is consequently prevented from rotating. An actuation of the fourth shift element 37 entails a connection of the second input shaft 24 for conjoint rotation to the first element 28 of the second planetary gear set 26, whereas the fifth shift element 38 in its closed state connects the first element 28 and the second element 30 of the first planetary gear set 26 for conjoint rotation. The latter results here in a locking of the second planetary gear set 26.

[0051] By selective actuation of the shift elements 34 to 38, the two electric machines 14 and 15 can be connected in different ways and thus also different operating modes can be provided. Thus, the second electric machine 15 can be coupled to the drive shaft 33 by closing either the third shift element 36, the fourth shift element 37 or the fifth shift element 38, it also being possible to implement an additional incorporation of the first electric machine 14 via the second input shaft 24 by a simultaneous actuation of the second shift element 35.

[0052] If, on the other hand, the first shift element 34 is actuated alone, a superimposition of drive movements of the two electric machines 14 and 15 can be caused at the second planetary gear set 20. In addition, if either the fourth shift element 37 or the fifth shift element 38 is actuated in addition to the first shift element 34, a sole drive via the first electric machine 14 can also be realized.

[0053] The first shift element 34 and the second shift element 35 are combined in the present case to form a shift device 39, the actuating device 40 of which can cause either the first shift element 34 or the second shift element 35 to be transferred from a neutral position into an actuated state. Likewise, the third shift element 36, the fourth shift element 37 and the fifth shift element 38 are also combined to form a shift device 41, to which an actuating device 42 is assigned. This actuating device 42, when moved out of a neutral position, depending on the position can transfer the third shift element 36, the fourth shift element 37 or the fifth shift element 38 into an actuated state.

[0054] As can be seen from FIG. 3, the electric machines 14 and 15, the multi-speed transmission 16 and also the distributor device 17 are arranged coaxially with respect to one another, the multi-speed transmission 16 and also the distributor device 17 being positioned here axially substantially in line with the two electric machines 14 and 15 and radially inwardly of them. The shift devices 39 and 41 are provided here axially in line with the first electric machine 14, while the two planetary gear sets 25 and 26 of the multi-speed transmission 16 and the distributor device 17 are located axially in the region of the second electric machine 15.

[0055] FIGS. 4 to 6 show possible embodiments of the distributor device 17 as they can be implemented in the drive unit 7 from FIG. 3. FIG. 4 shows an embodiment of the distributor device 17 with a bevel gear differential 43, via which a drive power introduced at the drive shaft 33 is distributed to the outputs 9 and 10 and thus to the drive axles 3 and 4 connected thereto in the sense of a longitudinal distribution. In this case, the drive shaft 33 is connected for conjoint rotation to a differential cage 44, in which two differential bevel gears 45 and 46 are each rotatably mounted on a pin 47. The differential bevel gears 45 and 46 mesh with output bevel gears 48 and 49 respectively, each of which is placed for conjoint rotation on an output shaft 50 and 51 respectively. In this case, the output shaft 50 forms the output 10 at one shaft end and the output shaft 51 forms the output 9 at one shaft end. The bevel gear differential 43 distributes the torque evenly here between the two output shafts 9 and 10, possibly compensating for speed differences.

[0056] By contrast, FIG. 5 shows a variant of the distributor device 17 in which the distributor device 17 comprises a planetary differential 52. The planetary differential 52 is composed of a sun gear 53, a planet web 54 and a ring gear 55, a plurality of planet gears 56 being rotatably mounted in the planet web 54, each of said planet gears being in meshing engagement with both the sun gear 53 and the ring gear 55. While the planet web 54 is connected for conjoint rotation to the drive shaft 33, the sun gear 53 is connected for conjoint rotation to the output shaft 50, and the ring gear 55 is connected for conjoint rotation to the output shaft 51. The output shafts 50 and 51 in turn form the outputs 10 and 9, respectively, at shaft ends, The planetary differential 52 also distributes torque to the outputs 9 and 10, possibly compensating for speed differences, but, in contrast to the bevel gear differential 43, uneven torque distribution is possible here.

[0057] In the possible embodiment of the distributor device 17 shown in FIG. 6, the drive shaft 33 is connected to the output shaft 51 for conjoint rotation, so that the drive shaft 33 and the output shaft 51 always rotate at the same speed. The output shaft 50 can be connected for conjoint rotation to the output shaft 51, and thus also to the drive shaft 33, via an intermediate clutch 57, whereby a drive power introduced at the drive shaft 33 is distributed evenly between the two output shafts 50 and 51 and equal rotational speeds of the output shafts 50 and 51 are forced. In contrast to the two preceding variants according to FIG. 4 or 5, in the embodiment of the distributor device 17 according to FIG. 6, accordingly, no permanent all-wheel drive is realized, since in a disengaged state of the clutch 57 there is no power flow to the output shaft 50 and thus to the output 10. Rather, in the case of the embodiment according to FIG. 6, the all-wheel drive can be selected by actuating the clutch 57.

[0058] Lastly, FIG. 7 shows a schematic view of a drive unit 58, which is realized in accordance with a second possible embodiment of the invention and can be used as an alternative to the drive unit 7 in the drivetrain 2. In contrast to the drive unit 7, in the case of the drive unit 58 the electric machines 14 and 15, the multi-speed transmission 16 and the distributor device 17 are arranged axially in succession, the electric machines 14 and 15, the multi-speed transmission 16 and the distributor device 17 lying coaxially here with respect to one another. In addition, the multi-speed transmission 16 is placed axially between the electric machines 14 and 15 on the one hand and the distributor device 17 on the other hand, Otherwise, the embodiment according to FIG. 7 corresponds to the variant according to FIGS. 3 to 6, and therefore reference is made to the description provided for those Figures.

[0059] By means of the embodiments according to the invention, a compact drive unit for an electric vehicle with permanent or selectable all-wheel drive can be provided.

REFERENCE SIGNS

[0060] 1 electric vehicle [0061] 2 drivetrain [0062] 3 drive axle [0063] 4 drive axle [0064] 5 front axle [0065] 6 rear axle [0066] 7 drive unit [0067] 8 axle differential [0068] 9 output [0069] 10 output [0070] 11 axle differential [0071] 12 cardan shaft [0072] 13 cardan shaft [0073] 14 first electric machine [0074] 15 second electric machine [0075] 16 multi-speed transmission [0076] 17 distributor device [0077] 18 stator [0078] 19 stator [0079] 20 rotor [0080] 21 rotor [0081] 22 housing [0082] 23 first input shaft [0083] 24 second input shaft [0084] 25 first planetary gear set [0085] 26 second planetary gear set [0086] 27 first element, first planetary gear set [0087] 28 first element, second planetary gear set [0088] 29 second element, first planetary gear set [0089] 30 second element, second planetary gear set [0090] 31 third element, first planetary gear set [0091] 32 third element, second planetary gear set [0092] 33 drive shaft [0093] 34 first shift element [0094] 35 second shift element [0095] 36 third shift element [0096] 37 fourth shift element [0097] 38 fifth shift element [0098] 39 shift device [0099] 40 actuating device [0100] 41 shift device [0101] 42 actuating device [0102] 43 bevel gear differential [0103] 44 differential cage [0104] 45 differential bevel gear [0105] 46 differential bevel gear [0106] 47 pin [0107] 48 output bevel gear [0108] 49 output bevel gear [0109] 50 output shaft [0110] 51 output shaft [0111] 52 planetary differential [0112] 53 sun gear [0113] 54 planet web [0114] 55 ring gear [0115] 56 planetary gears [0116] 57 clutch [0117] 58 drive unit