Drive system for a motor vehicle, corresponding motor vehicle and method for operating a drive system

Abstract

Drive unit (12) for a motor vehicle (1) with only one driven wheel axle, comprising a first drive unit (13), a second drive unit (14) and an output shaft (15) that can be coupled or connected to a wheel drive shaft (8) of the motor vehicle (1), wherein the first drive unit (13) and the second drive unit (14) can be coupled together with the output shaft (15), wherein the second drive unit (14) can be coupled via a disconnect clutch (26) designed as a positive-locking clutch to a transmission output shaft (20) of a transmission (19) that can be coupled or connected to the first drive unit (13), characterized in that the second drive unit (14) is designed for a lower maximum speed than the first drive unit (13), taking into account the transmission (19).

Description

[0001] The invention relates to a drive unit for a motor vehicle with only one driven wheel axle, comprising a first drive unit, a second drive unit, and an output shaft that can be coupled to or connected to a wheel drive shaft of the motor vehicle, wherein the first drive unit and the second drive unit can be coupled together to the output shaft, and wherein the second drive unit is coupled to a transmission output shaft of a transmission that can be coupled to or connected to the first drive unit via a disconnect clutch designed as a positive-locking coupling. The invention further relates to a motor vehicle and a method for operating a drive unit.

[0002] For example, the prior art document DE 42 11 586 A1 describes a drive device for a hybrid vehicle with an internal combustion engine that drives at least one axle of the vehicle via a transmission and a differential, and with an electric motor that can also be coupled to a driven axle, wherein, in order to achieve an improved operating range of the electric motor, it drives the axles via a hydraulically switchable planetary gear with at least two gear ratios.

[0003] Furthermore, the following documents are known from the prior art: DE 195 30 231 A1, DE 10 2014 019 431 A1, DE 10 2011 101 410 A1 and WO 2009 / 021 574 A1.

[0004] The drive system serves to propel the motor vehicle, thus providing torque for its propulsion. The drive system comprises a first drive unit and a second drive unit. These two drive units can be of the same or different types. In the latter case, the drive system is, for example, a hybrid drive system. It is possible for the first drive unit to be an internal combustion engine and the second drive unit an electric motor.

[0005] The drive unit has exactly one or more output shafts, namely the first output shaft and / or the second output shaft. Each of the two output shafts can be coupled to, or is coupled to, one of the wheel drive shafts of the motor vehicle, preferably rigidly and / or permanently. The wheel drive shafts, i.e., the first wheel drive shaft and the second wheel drive shaft, can—not according to the invention—be assigned to different wheel axles of the motor vehicle or, according to the invention, to the same wheel axle of the motor vehicle. At least one wheel of the motor vehicle or of the respective wheel axle can be driven by the drive unit via each of the wheel drive shafts. For example, the respective wheel is rigidly and / or permanently coupled to the corresponding wheel drive shaft.

[0006] The motor vehicle can have only the first wheel drive shaft, or at least one first wheel drive shaft, or only the second wheel drive shaft, or at least one second wheel drive shaft. In this respect, according to the invention, only one wheel axle of the motor vehicle can be driven. Accordingly, only the first output shaft or the second output shaft is present. Alternatively, however, the first wheel drive shaft and the second wheel drive shaft, or at least one first wheel drive shaft and at least one second wheel drive shaft, can be present, so that – not according to the invention – several wheel axles of the motor vehicle can be driven. Accordingly, both the first output shaft and the second output shaft are present.If this description describes an embodiment in which both wheel drive shafts or both output shafts are present, the descriptions can always be used for an alternative embodiment in which only the first wheel drive shaft or the second wheel drive shaft and, accordingly, only the first output shaft or the second output shaft are present.

[0007] Naturally, it can also be provided that at least one or both of the wheel drive shafts can drive several wheels of the vehicle, in particular several wheels on the same axle. In the latter case, for example, not only is the first wheel drive shaft coupled or connectable to the first output shaft, but also an additional first wheel drive shaft. Preferably, in this case, the first wheel drive shaft and the additional wheel drive shaft are coupled to the first output shaft via a differential. The first wheel drive shaft and the additional first wheel drive shaft are, for example, assigned to the same axle of the vehicle, i.e., coupled to different wheels on this axle. The same applies to the second output shaft and the second wheel drive shaft. Here, too, an additional wheel drive shaft can be provided.

[0008] If the drive unit is not yet installed in the vehicle, i.e., it exists separately, the two wheel drive shafts are preferably designed to be coupled to their respective wheel drive shafts. After the drive unit is installed in the vehicle, the output shafts are preferably each coupled to the corresponding wheel drive shaft. If one unit is capable of being coupled to another, this means that the operative connection between them exists only temporarily, in particular that it is selectively established or interrupted. If, on the other hand, the unit is coupled to the other, this preferably means a permanent and / or rigid coupling.

[0009] The object of the invention is to propose a drive device for a motor vehicle which has advantages over known drive devices, in particular enabling energy-saving propulsion of the motor vehicle over numerous operating states, especially when implementing single-axle operation.

[0010] According to the invention, this is achieved with a drive unit having the features of claim 1. It is provided that the second drive unit, taking into account the transmission, is designed for a lower maximum speed than the first drive unit.

[0011] Within the drive system described here, the first drive unit and the second drive unit can be coupled together with the first output shaft and / or the second output shaft, i.e., the first output shaft, the second output shaft, or both. This means that in at least one operating mode of the drive system, both drive units are coupled together with the first output shaft, the second output shaft, or both. Furthermore, it can be provided that the first drive unit can be coupled to the first output shaft separately from the second drive unit. In this case, the first drive unit can be coupled to the first output shaft, while the second drive unit is simultaneously decoupled from the first output shaft.

[0012] The first drive unit and / or the transmission output shaft is preferably coupled or connectable to the transmission shaft. In the former case, a permanent operative connection is provided, whereas in the latter case, the operative connection is interruptible. For example, a first clutch is provided between the first drive unit or the transmission output shaft on the one hand and the transmission shaft on the other, such that in a first switching position of the first clutch, the operative connection between the first drive unit and the first output shaft is interrupted, and in a second switching position, it is at least partially, but preferably rigidly, established.

[0013] The transmission shaft is preferably coupled or connectable to the second output shaft. In the former case, the transmission shaft is permanently operatively connected to the second output shaft. In the latter case, however, it can be decoupled from the second output shaft, for example, by a second clutch between the transmission shaft and the second output shaft. Accordingly, in a first switching position of the second clutch, the operative connection between the transmission shaft and the second output shaft can be interrupted and, in a second switching position, established, again at least partially, preferably rigidly.

[0014] The transmission shaft is, for example, in the form of a driveshaft, such as a cardan shaft. In this respect, the first wheel drive shaft, which is not connected to the transmission shaft but rather bypassing it, is preferably assigned to a first wheel axle of the vehicle, and the second output shaft to a second wheel axle, which is different from the first. For example, the first wheel axle is in the form of a front axle of the vehicle and the second wheel axle is in the form of a rear axle of the vehicle, or vice versa.

[0015] The second drive unit is connected to the transmission output shaft via the disconnect clutch. This means that in the first switching position of the disconnect clutch, the operative connection between the second drive unit and the other device is interrupted, and in the second switching position, it is at least partially, but preferably rigidly, established. The disconnect clutch thus allows the second drive unit to be completely decoupled from the corresponding device.

[0016] The disconnect coupling is configured – not according to the invention – as a friction coupling or – according to the invention – as a positive-locking coupling. The friction coupling is in particular designed as a multi-plate coupling, whereas the positive-locking coupling can be a jaw coupling, sleeve coupling, or the like. In any case, however, the disconnect coupling enables the complete decoupling of the second drive unit from the first output shaft and / or the second output shaft, namely by completely decoupling it from the respective device with which it can be coupled via the disconnect coupling. The device in question is therefore understood to be the transmission output shaft.

[0017] The term "transmission" preferably refers to a gear-shifting transmission by means of which a gear can be selected from several available gears, corresponding to a specific gear ratio. The gear-shifting transmission is preferably located between the first drive unit on the one hand and the first output shaft and / or the second drive unit and / or the transmission shaft and / or the differential output shaft on the other. Furthermore, a starting clutch may be provided between the first drive unit and the transmission. However, the starting clutch can, of course, also be integrated into the transmission.

[0018] The differential is preferably a center differential. A differential input shaft of the differential is preferably connectable to the first drive unit, for example via the transmission or gearbox. A first differential output shaft of the differential is connectable to, or connected to, the first output shaft, and a second differential output shaft is connected to the second output shaft. The aforementioned differential output shaft can be either the first or the second differential output shaft; preferably, it corresponds to the first differential output shaft.

[0019] In known drive systems, for example, the first drive unit can be coupled to the second drive unit via the aforementioned starting clutch, and the second drive unit can then be coupled to one, several, or all of the wheel drive shafts. The transmission may include a gear selector in the operative connection between the second drive unit and at least one wheel drive shaft, allowing the selected gear to be chosen from several available gears. In this respect, the second drive unit is always coupled to the output shaft, while the first drive unit can be selectively engaged via the starting clutch.

[0020] However, this also means that the second drive unit is always dragged along, even when it is not needed to provide the drive torque for the vehicle. For this reason, it is particularly necessary to design the second drive unit in such a way that it is suitable for all speeds achievable with the first drive unit, which can result in a comparatively large design for the second drive unit. Therefore, it is now planned to decouple the second drive unit from other elements of the drive system by means of a disconnect clutch.

[0021] This means that the second drive unit is only coupled to, or becomes coupled to, one of the output shafts when one or both of the output shafts are driven by the second drive unit. In single-axis operation, for example, only one of the output shafts is driven by the second drive unit. However, multi-axis operation of the drive unit is also possible – though not according to the invention – in which a drive torque is provided to both output shafts, preferably by both the first and the second drive unit. In the latter case, preferably both the first and the second drive unit are coupled to both the first and the second output shafts.

[0022] Accordingly, it may be provided, for example, that the second drive unit is designed only for a speed and / or vehicle speed range that occurs during multi-axle operation. According to the invention, the second drive unit is designed for a lower maximum speed than the first drive unit, so that the second drive unit can be significantly smaller than in known designs. When determining the maximum speed, the transmission or gearshift mechanism must be taken into account, since it is located between the first and second drive units.

[0023] The second drive unit is preferably arranged coaxially with the transmission output shaft and / or the transfer shaft. However, an arrangement alongside the transmission output shaft and / or the transfer shaft, in particular an axially parallel arrangement to the transmission output shaft and / or the transfer shaft, is also possible.

[0024] A further embodiment of the invention provides that the first drive unit can be coupled to the transmission shaft by means of a first clutch, which is coupled to the second output shaft or can be coupled to the second output shaft via a second clutch. Such an embodiment has already been mentioned above. With the aid of the two clutches, i.e., the first and second clutch, the transmission shaft can be completely decoupled from both the first drive unit and the second output shaft.

[0025] Accordingly, it may be possible to disable the transmission shaft if and / or while the second output shaft is not to be driven by the first drive unit. This saves the drive power otherwise required to maintain the rotation of the transmission shaft, which would otherwise have to be supplied by the first drive unit and / or via the second drive shaft. Such a design already enables a certain degree of energy savings because not only the second drive shaft can be coupled to the first drive unit, but also the transmission shaft.

[0026] In a further embodiment of the invention, the second drive unit can be coupled to the input side of the first clutch via the disconnect clutch. The input side of the first clutch is thus located away from the transmission shaft and can be selectively decoupled or coupled to it. The input side of the first clutch is coupled, or at least connectable, to the first drive unit and / or the transmission output shaft. The disconnect clutch is located between the second drive unit and the input side of the first clutch, allowing the second drive unit to be directly connected to the input side of the first clutch via the disconnect clutch.

[0027] Another preferred embodiment of the invention provides that the differential gear output shaft of the differential gear is coupled to the first output shaft, in particular via a further differential gear. The differential gear output shaft corresponds in this respect to the first differential gear output shaft already mentioned above, which is coupled to the first output shaft, preferably permanently. The operative connection between the differential gear output shaft and the first output shaft can be established via the further differential gear, which is, for example, designed as an axle differential.

[0028] In a further embodiment of the invention, a further differential gear output shaft of the differential gear can be coupled or couplingable to the transmission shaft. This further differential gear output shaft corresponds in this respect to the aforementioned second differential gear output shaft, via which the operative connection to the second output shaft can be established. For this purpose, the further differential gear output shaft is coupled or couplingable to the transmission shaft. In the former case, the further differential gear output shaft is rigidly and / or permanently coupled to the transmission shaft, while in the latter case, for example, the first clutch is located between the further differential gear output shaft and the transmission shaft.

[0029] Finally, in a preferred embodiment of the invention, the first drive unit and / or the transmission output shaft of the transmission may be coupled to the transmission shaft, and the first output shaft may be coupled to the transmission shaft via the first clutch, and the second drive unit may be coupled to the transmission shaft via the disconnect clutch and the first clutch. In this case, the first drive unit and / or the transmission output shaft is rigidly and / or permanently connected to the transmission shaft. Furthermore, the first output shaft should be coupled to the transmission shaft via the first clutch.

[0030] The second drive unit can now be coupled to the transmission shaft via the disconnect clutch and the first clutch. Therefore, if the second drive unit is connected to the transmission shaft, this connection exists exclusively via the disconnect clutch and the first clutch. Thus, the second drive unit is only operatively connected to the transmission shaft when both the disconnect clutch and the first clutch are engaged, at least partially or completely.

[0031] The invention further relates to a motor vehicle with a drive unit, in particular a drive unit according to one or more of the preceding claims, wherein the drive unit comprises a first drive unit, a second drive unit, and an output shaft coupled to a wheel drive shaft of the motor vehicle, wherein the first drive unit and the second drive unit can be coupled together with the output shaft. It is provided that the second drive unit can be coupled to a transmission output shaft of a transmission coupled to the first drive unit via a positive-locking disconnect clutch. Furthermore, it is provided that the second drive unit is designed for a lower maximum speed than the first drive unit, taking the transmission into account.

[0032] The advantages of such a design for the motor vehicle or the drive system have already been mentioned. Both the motor vehicle and the drive system can be further developed in accordance with the above explanations, and reference is made to these in that regard.

[0033] Finally, the invention relates to a method for operating a drive unit, in particular a drive unit according to the foregoing descriptions, wherein the drive unit comprises a first drive unit, a second drive unit, and an output shaft that can be coupled to or is coupled to a wheel drive shaft of the motor vehicle, wherein the first drive unit and the second drive unit can be coupled together with the output shaft. It is provided that the second drive unit can be coupled to a transmission output shaft of a transmission coupled to the first drive unit via a disconnect clutch designed as a positive-locking coupling. Furthermore, it is provided that the second drive unit is designed for a lower maximum speed than the first drive unit, taking the transmission into account.

[0034] Reference is again made to the above statements regarding the advantages of such a design or such a procedure, as well as regarding possible further training.

[0035] In a further embodiment of the invention, it is provided that in a first operating mode, the second drive unit is coupled to the first output shaft and decoupled from the second output shaft, and / or that in a second operating mode, the second drive unit is coupled to both the first and second output shafts. In the first operating mode, the second drive unit serves only to drive the first output shaft, while the operative connection to the second output shaft is interrupted. The additionally or alternatively provided second operating mode, however, provides for the second drive unit to drive both the first and second output shafts.

[0036] Finally, another embodiment of the invention provides that if the rotational speed of the second drive unit exceeds a limit, a third operating mode is activated in which the disconnect clutch is open to decouple the second drive unit. If the vehicle's speed exceeds a certain maximum speed and, consequently, the rotational speed also exceeds the limit or maximum speed, the second drive unit should be decoupled from other elements of the drive system to protect it, namely by opening the disconnect clutch. If the vehicle's speed subsequently falls below the maximum speed and thus the rotational speed below the limit, the disconnect clutch can be at least partially, preferably completely, closed again to re-engage the second drive unit.

[0037] The invention is explained in more detail below with reference to the exemplary embodiments shown in the drawing, without limiting the invention. The drawing shows: Fig. 1 a schematic representation of a motor vehicle with a drive unit in a first embodiment, Fig. 2 the motor vehicle in a schematic representation in a second embodiment of the drive device, as well as Fig. 3 the motor vehicle in the already known schematic representation with the drive device designed in a third embodiment.

[0038] The Fig. Figure 1 shows a schematic representation of a motor vehicle 1 with two wheel axles 2 and 3, wherein each wheel axle 2 and 3 is assigned two wheels 4 and 5 or 6 and 7 respectively, which are each coupled to a wheel drive shaft 8, 9, 10 or 11 respectively, in particular rigidly. The motor vehicle 1 has a drive unit 12 which comprises a first drive unit 13 and a second drive unit 14. Furthermore, the drive unit 12 has a first output shaft 15 and a further first output shaft 16, as well as a second output shaft 17 and a further second output shaft 18. In the embodiment shown here, the first output shaft 15 is coupled to the wheel drive shaft 8, the further first output shaft 16 to the wheel drive shaft 9, the second output shaft to the wheel drive shaft 10, and the further second output shaft 18 to the wheel drive shaft 11, in particular rigidly.

[0039] It should be noted that the output shafts 15, 16, 17 and 18 are part of the drive unit 12, while the wheel drive shafts 8, 9, 10 and 11 are assigned to a chassis of the motor vehicle 1 (not shown) and are therefore not part of the drive unit 12. However, when the drive unit 12 is mounted on the motor vehicle 1, the output shafts 15, 16, 17 and 18 are connected to or coupled with the wheel drive shafts 8, 9, 10 and 11.

[0040] The first drive unit 13 is coupled to a transmission 19, for example, a gearbox. On its side facing away from the first drive unit 13, the transmission 19 has a transmission output shaft 20. The transmission output shaft 20 is preferably rigidly and permanently coupled to the output shafts 15 and 16, for example, via an axle differential 21. A clutch, in particular a starting clutch, can be provided between the first drive unit 13 and the transmission 19. Accordingly, the first drive unit 13 can be coupled to the first output shafts 15 and 16, namely via the transmission 19 and the starting clutch typically provided. The starting clutch is present, in particular, when the first drive unit 13 is designed as an internal combustion engine. In contrast, such a starting clutch is not necessarily present when the first drive unit 13 is designed as an electric motor or the like.

[0041] The drive unit 12 further comprises a transmission shaft 22, which can be coupled to the first drive unit 13 or at least to the transmission output shaft 20 by means of a first clutch 23, which can be designed as a multi-plate clutch. On the side of the transmission shaft 22 opposite the first clutch 23, it can be coupled to the second output shaft 17 via a second clutch 24. The second clutch 24 can be a dog clutch or also a multi-plate clutch. In the embodiment shown here, the transmission shaft 22 is coupled, or can be coupled, to the second output shafts 17 and 18 via a differential 25, in particular an axle differential. The transmission shaft 22 is thus designed as the input shaft of the differential.

[0042] A differential gear output shaft of the differential gear 25 can be coupled to the second output shaft 17 via the second clutch 24, which is preferably rigidly and permanently coupled to a further differential gear output shaft 18. When the second clutch 24 is open, the transmission shaft 22 is thus decoupled from the second output shafts 17 and 18, or at least from the second output shaft 17, at least under ideal frictionless conditions.

[0043] It becomes clear that with the clutches 23 closed, the first drive unit 13 is coupled to both the first output shaft 15 and the second output shaft 16. The second drive unit 14, on the other hand, can be coupled to the transmission output shaft 20 via a disconnect clutch 26, which can be designed as a multi-plate clutch, dog clutch, or sleeve clutch. With the disconnect clutch 26 open, the second drive unit 14 is thus decoupled from other elements of the drive system 12, namely, in particular, the transmission output shaft 20. In this respect, the second drive unit 14 can be engaged selectively.

[0044] Thus, using only the first drive unit 13, with the disconnect clutch 26 simultaneously open, both single-axle and multi-axle operation of the motor vehicle 1 can be achieved, namely by appropriately opening or closing the switching clutches 23 and 24. The first drive unit 13 can be supported in both single-axle and multi-axle operation by means of the second drive unit 14, for which the disconnect clutch 26 is at least partially, preferably completely, closed.

[0045] In an alternative embodiment, the transmission shaft 22, the differential gear 25, the second shift clutch 24 and the two second output shafts 17 and 18 are not present, so that only the first wheel axle 2 of the motor vehicle 1 can be driven.

[0046] The Fig. Figure 2 shows the motor vehicle 1 in a further schematic representation, with the drive unit 12 in a second embodiment. This is fundamentally similar to the embodiment described above, so reference is made to the corresponding versions, and only the differences are noted below. These differences lie essentially in the fact that the shift clutches 23 and 24 are not present, and instead the transmission shaft 22 is connected to the first drive unit 13 or the transmission output shaft 20 via a differential gear 27. The transmission output shaft 20 thus represents a differential gear input shaft of the differential gear 27.

[0047] The differential 27 is a center differential. A first differential output shaft 28 is connected to the first output shaft 15 or to both first output shafts 15 and 16, preferably via the axle differential 21. A second differential output shaft 29 of the differential 27, on the other hand, is rigidly connected to, or forms, the transmission shaft 22. The second drive unit 14 can now be coupled to the first differential output shaft 28 by means of the disconnect clutch 26, preferably rigidly.

[0048] The Fig.Figure 3 shows the motor vehicle 1 with a third embodiment of the drive unit 12. Reference is again made to the preceding descriptions, and only the differences are noted, particularly compared to the second embodiment. These differences lie in the fact that the first clutch 23 is present instead of the differential gear 27. The first drive unit 13, or the transmission output shaft 20, is rigidly and / or permanently coupled to the transmission shaft 22. The first output shaft 15, or both first output shafts 15 and 16, can be coupled to the transmission shaft 22 via the first clutch 23. Similarly, the first output shaft 15, or the output shafts 15 and 16, are coupled to an intermediate shaft 30, in particular rigidly and / or permanently, preferably via the axle differential gear 21.The intermediate shaft 30 can in turn be coupled to the transmission shaft 22 by means of the first switching clutch 23.

[0049] The disconnect clutch 26 is now connected to the transmission shaft 22 on its side facing away from the second drive unit 14. Accordingly, with the first shift clutch open and the disconnect clutch 26 closed, the second output shaft 17, or the two second output shafts 17 and 18, can be coupled to the second drive unit 14, but at the same time decoupled from the first drive unit 13.

[0050] Alternatively, the second drive unit 14 can also be coupled to the intermediate shaft 30 by means of the disconnect clutch 26. This means that when the first shift clutch 23 is open and the disconnect clutch 26 is closed, the first output shaft 15, or the first two output shafts 15 and 16, are coupled to the second drive unit 14, but simultaneously decoupled from the first drive unit 13.

[0051] In an alternative embodiment, the first shift clutch 23, the differential gear 21 and the two first output shafts 15 and 16 are not present, so that only the second wheel axle 3 of the motor vehicle 1 can be driven.

Claims

[1] Drive unit (12) for a motor vehicle (1) with only one driven wheel axle, comprising a first drive unit (13), a second drive unit (14) and an output shaft (15) that can be coupled or connected to a wheel drive shaft (8) of the motor vehicle (1), wherein the first drive unit (13) and the second drive unit (14) can be coupled together with the output shaft (15), wherein the second drive unit (14) can be coupled via a disconnect coupling (26) designed as a positive-locking coupling to a transmission output shaft (20) of a transmission (19) that can be coupled or connected to the first drive unit (13), characterized by , that the second drive unit (14) is designed for a lower maximum speed than the first drive unit (13), taking into account the transmission (19). [2] Drive device according to claim 1, characterized by that the positive-locking coupling is in the form of a claw coupling or sleeve coupling. [3] Drive device according to one of the preceding claims, characterized by , that the transmission (19) is designed as a gear-changing transmission. [4] Drive device according to one of the preceding claims, characterized by , that a starting clutch is present between the first drive unit (13) and the transmission (19) or that the starting clutch is integrated into the transmission (19). [5] Drive device according to one of the preceding claims, characterized by , that the second drive unit (14) is arranged parallel to the axis of the transmission output shaft (20). [6] Motor vehicle (1) with a drive unit (12) according to one or more of the preceding claims, and with only one driven axle, wherein the drive unit (12) comprises a first drive unit (13), a second drive unit (14) and an output shaft (15) coupled to a wheel drive shaft (8) of the motor vehicle (1), wherein the first drive unit (13) and the second drive unit (14) can be coupled together with the output shaft (15), wherein the second drive unit (14) can be coupled via a disconnect clutch (26) designed as a positive-locking clutch to a transmission output shaft (20) of a transmission (19) coupled to the first drive unit (13), characterized by , that the second drive unit (14) is designed for a lower maximum speed than the first drive unit (13), taking into account the transmission (19). [7] Method for operating a drive unit (12) for a motor vehicle (1) with only one driven axle according to one or more of the preceding claims, wherein the drive unit (12) comprises a first drive unit (13), a second drive unit (14) and an output shaft (15) that can be coupled to or is coupled to a wheel drive shaft (8) of the motor vehicle (1), wherein the first drive unit (13) and the second drive unit can be coupled together with the output shaft (15), wherein the second drive unit (14) can be coupled to a transmission output shaft (20) of a transmission (19) coupled to the first drive unit (13) via a disconnect clutch (26) designed as a positive-locking clutch, characterized by , that the second drive unit (14) is designed for a lower maximum speed than the first drive unit (13), taking into account the transmission (19).

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