Drive system for a motor vehicle

Abstract

Drive system (1) for a motor vehicle (2), wherein the drive system (1) comprises: a first axle drive (4) driving a first vehicle axle (3) and housed in a first drive train housing (13), comprising a first electric machine (5) and a first transmission arrangement (7) forming a first structural unit (6) with the first electric machine (5); and a second axle drive (9) driving a second vehicle axle (8) and housed in a second drive train housing (14), comprising a second electric machine (10) and a second transmission arrangement (12) forming a second structural unit (11) with the second electric machine (10), wherein the first electric machine (5) and the second electric machine (10), as well as the first transmission arrangement (7) and the second transmission arrangement (12), are essentially identical in construction.the first drivetrain housing (13) defines a first oil sump (16) containing a first oil (15) and the second drivetrain housing (14) defines a second oil sump (18) containing a second oil (17), wherein the receiving volume of the first oil sump (16) corresponds to between 0.75 and 1.25 of the receiving volume of the second oil sump (18), characterized in that the first axle drive train (4) and the second axle drive train (9) are arranged in the drive system (1) rotated relative to each other by an angle of 10° to 90° with respect to the axes of rotation of the respective electric machines (5, 10), the first drivetrain housing (13) defines a first gear chamber (20) for receiving the first gear assembly (7), from which the first oil (15) can be conveyed into the first oil sump (16) via a first oil outlet opening (21), and / or the second drivetrain housing (14) defines a second gearbox compartment (22) defined for accommodating the second gearbox assembly (12),from which the second oil (17) can be conveyed via a second oil outlet opening (23) into the second oil sump (18), the first gear arrangement (7) has a first gear (34) rotatable parallel to the axis of rotation of the first electric machine (5), through which the first oil (15) located in the first gear chamber (20) can be conveyed from the first gear chamber (20) through the first oil outlet opening (21) into the first oil sump (16), and / or the second gear arrangement (12) has a second gear (24) rotatable parallel to the axis of rotation of the second electric machine (10), through which the second oil (17) located in the second gear chamber (22) can be conveyed from the second gear chamber (22) through the second oil outlet opening (23) into the second oil sump (18).

Description

[0001] The present invention relates to a drive system for a motor vehicle comprising a first axle drive train, which drives a first vehicle axle and is housed in a first drive train housing. with a first electric machine and a first transmission arrangement forming a first structural unit with the first electric machine and a second axle drive train housed in a second drive train housing and driving a second vehicle axle with a second electric machine and a second gear arrangement forming a second structural unit with the second electric machine, wherein the first electric machine and the second electric machine as well as the first gear arrangement and the second gear arrangement are essentially identical in construction.

[0002] Electric motors are increasingly being used for propulsion in motor vehicles to create alternatives to combustion engines that require fossil fuels. Considerable efforts have already been made to improve the everyday usability of electric drives and to offer users the familiar driving comfort.

[0003] A detailed description of an electric drive system can be found in an article in the journal ATZ, Volume 113, 05 / 2011, pages 360-365, by Erik Schneider, Frank Fickl, Bernd Cebulski, and Jens Liebold, entitled: "Highly Integrated and Flexible Electric Drive Unit for E-Vehicles." This article describes a drive unit for one axle of a vehicle, comprising an electric motor arranged concentrically and coaxially to a bevel gear differential. A switchable two-speed planetary gear set is located in the powertrain between the electric motor and the bevel gear differential, also positioned coaxially to the electric motor and the bevel or spur gear differential. The drive unit has a very compact design and, thanks to the switchable two-speed planetary gear set, allows for a good compromise between climbing ability, acceleration, and energy consumption.Such drive units are also referred to as e-axles or electrically operated axle drive trains.

[0004] From DE 10 2010 048 837 A1, such a drive device is known, comprising at least one electric motor and at least one planetary differential driven by a rotor of the electric motor. The planetary differential has at least one planet carrier operatively connected to a rotor of the electric motor, first planet gears and second planet gears rotatably mounted on the planet carrier, and a first sun gear and a second sun gear, each of which is operatively connected to an output shaft of the planetary differential. The first planet gears mesh with the first sun gear, and each of the second planet gears meshes with the second sun gear and with one of the first planet gears. Furthermore, the sun gears are arranged coaxially with a rotational axis of the rotor.

[0005] An axial flux machine is a dynamoelectric machine in which the magnetic flux between the rotor and stator runs parallel to the rotor's axis of rotation. Often, both the stator and rotor are largely disk-shaped. Axial flux machines are particularly advantageous when the available axial installation space is limited in a given application. This is frequently the case, for example, with the electric drive systems for electric or hybrid vehicles described earlier.

[0006] Besides its shorter axial length, another advantage of the axial flux machine lies in its comparatively high torque density. This is due to the larger air gap area available within a given installation space compared to radial flux machines. Furthermore, a smaller iron volume is required compared to conventional machines, which has a positive effect on the machine's efficiency.

[0007] An axial flux machine typically comprises at least one stator, which has windings to generate the axially aligned magnetic field. At least one rotor is equipped, for example, with permanent magnets whose magnetic field, interacting with the magnetic field of the stator windings across an air gap, generates a driving torque.

[0008] In the development of electric motors and gearboxes intended for e-axles, there is a continuing need to increase their power densities, making the necessary cooling of the electric motors and gearboxes increasingly important. Due to the required cooling capacity, hydraulic fluids, such as cooling oils, have become the standard in most designs for dissipating heat from the thermally stressed areas of an electric motor and / or gearbox.

[0009] The gearboxes typically used in the aforementioned e-axles are usually lubricated with gear oil, which often also serves as cooling oil for the electric motor. To reliably deliver the lubricant or cooling oil to the various lubrication and cooling points, it is known to incorporate a corresponding hydraulic fluid circuit within the e-axles.

[0010] Therefore, it is quite common to form an oil sump within an e-axle to store the amount of oil necessary for lubrication and cooling, from which the aforementioned hydraulic fluid circuit is supplied with oil.

[0011] Especially in fully electric vehicle drive systems, it is increasingly common to equip both axles with their own electrically driven axle drive train. To save costs, there is a continuing need to use as many identical parts as possible in the respective axle drive trains of the front and rear axles.

[0012] The object of the invention is therefore to solve or at least mitigate the problems known from the prior art and to realize a drive system for a motor vehicle with two axle drive trains that can be manufactured cost-effectively and provides an effective and cost-efficient cooling system.

[0013] This task is solved by a drive system for a motor vehicle comprising a first axle drive train, which drives a first vehicle axle and is housed in a first drive train casing. with a first electric machine and a first transmission arrangement forming a first structural unit with the first electric machine and a second axle drive train housed in a second drive train housing and driving a second vehicle axle with a second electric machine and a second gear arrangement forming a second structural unit with the second electric machine, wherein the first electric machine and the second electric machine as well as the first gear arrangement and the second gear arrangement are essentially identical in construction, wherein the first axle drive train and the second axle drive train are arranged in the drive system rotated by an angle of 10-90° to each other with respect to the axes of rotation of the respective electric machines, and wherein the first drive train housing defines a first oil sump containing a first oil, and the second drive train housing defines a second oil sump containing a second oil, wherein the receiving volume of the first oil sump corresponds to between 0.75-1.25 of the receiving volume of the second oil sump.

[0014] This offers the advantage of providing a drive system with two axle drive trains which, despite the different installation positions of the axle drive trains, achieves high efficiency through hydraulic cooling while maintaining a high degree of component commonality. The drive system according to the invention allows for different axle orientations of the two axle drive trains relative to each other simply by using different drive train housings. This enables, for example, a first axle drive train to be arranged in a space-optimized manner in the front axle area, and a second axle drive train, rotated relative to the first, to be arranged in a space-optimized manner in the rear axle area, even though virtually the same components (electric motor, transmission assembly) are used.

[0015] First, the individual elements of the claimed subject matter of the invention are explained in the order in which they are mentioned in the claim set, and subsequently, particularly preferred embodiments of the subject matter of the invention are described.

[0016] The drive system according to the invention comprises at least two electrically operated axle drive trains for driving two vehicle axles, with each axle drive train being assigned to one vehicle axle. An electrically operated axle drive train comprises an electric motor and a transmission assembly coupled to the electric motor. The transmission assembly and the electric motor form a single structural unit. This unit can, for example, be formed by means of a drive train housing in which the transmission assembly and the electric motor are jointly accommodated. The drive train housing can be designed as a single piece or in multiple parts.

[0017] For example, it would also be possible for the electric motor to have a motor housing and / or the transmission a transmission housing, with the structural unit then being achieved by fixing the transmission to the electric motor. In such a case, the motor housing and the transmission housing form part of the drivetrain housing.

[0018] The motor housing of one of the electric machines and / or a gearbox housing of one of the gearbox assemblies can each be housed in a drivetrain housing. The drivetrain housing is preferably made of a metallic material, particularly preferably aluminum, gray cast iron, or cast steel, and is preferably formed by a primary forming process such as casting or die casting. However, it would also be possible to manufacture the drivetrain housing from a plastic. The drivetrain housing can particularly preferably have a cup-shaped base, allowing the electric machine and the gearbox assembly to be inserted into the drivetrain housing through its open end face.

[0019] The gearbox housing is a housing for a gearbox assembly. Its function is to guide the shafts over the bearings and to grant the gears (and possibly cam discs) the necessary degrees of freedom under all loads, without restricting their rotational and, if applicable, linear motion, as well as to absorb bearing forces and support moments. A gearbox housing can be single- or multi-shell, i.e., undivided or split. The gearbox housing should, in particular, dampen noise and vibrations and be able to reliably contain lubricant. The gearbox housing is preferably made of a metallic material, especially aluminum, gray cast iron, or cast steel, and is formed, in particular, by a primary forming process such as casting or die casting. The gearbox housing can be manufactured as a single piece or in multiple parts.

[0020] The motor housing encloses the electric motor. It can also house the control and power electronics. Furthermore, the motor housing can be part of a cooling system for the electric motor and may be designed to supply cooling fluid to the electric motor via the housing and / or dissipate heat to the outside through the housing surfaces. In addition, the motor housing protects the electric motor and any electronics it may contain from external influences.

[0021] An engine housing can be made of a metallic material. Advantageously, the engine housing can be formed from a metallic casting material, such as die-cast aluminum, die-cast magnesium, gray cast iron, or cast steel. The engine housing can be manufactured as a single piece or in multiple parts.

[0022] An electric machine of an axle drive train of the drive system serves to convert electrical energy into mechanical energy and / or vice versa, and it usually comprises a stationary part called a stator, stator or armature, and a part called a rotor or runner which is arranged to be movable, in particular rotatable, relative to the stationary part.

[0023] An electric machine can be designed as a radial flux machine or as an axial flux machine.

[0024] An electric machine of an axle drive train of the drive system according to the invention is preferably designed as an axial flux machine. The magnetic flux in an electric axial flux machine (AFM) is directed axially in the air gap between the stator and rotor to a direction of rotation of the rotor of the axial flux machine. There are different types of axial flux machines. One known type is a so-called I-arrangement, in which the rotor is arranged axially next to a stator or between two stators. Another known type is a so-called H-arrangement, in which two rotors are arranged on opposite axial sides of a stator. The electric axial flux machine is preferably configured as an I-type.

[0025] In principle, it is also possible for multiple rotor-stator configurations of I-type and / or H-type to be arranged axially side by side. It would also be possible in this context to arrange one or more I-type rotor-stator configurations and one or more H-type rotor-stator configurations axially side by side. In particular, it is also preferred that the H-type and / or I-type rotor-stator configurations are essentially identical, so that they can be assembled modularly into a complete configuration. Such rotor-stator configurations can, in particular, be arranged coaxially to one another and be connected to a common rotor shaft or to multiple rotor shafts.

[0026] In particular, the electric machine is dimensioned such that vehicle speeds greater than 50 km / h, preferably greater than 80 km / h, and especially greater than 100 km / h, can be achieved. The electric motor is particularly preferably configured to have a power output greater than 30 kW, preferably greater than 50 kW, and especially greater than 70 kW. It is further preferred that the electric machine provides rotational speeds greater than 5,000 rpm, particularly preferably greater than 10,000 rpm, and most preferably greater than 12,500 rpm.

[0027] For the purposes of this application, motor vehicles are defined as land vehicles that are moved by mechanical power and are not bound to railway tracks. A motor vehicle may be selected, for example, from the groups of passenger cars, trucks, mopeds, light vehicles, motorcycles, buses, or tractors.

[0028] The transmission arrangement can be coupled, in particular, to an associated electric machine of the axle drive train, which is designed to generate drive torque for the motor vehicle. This drive torque is preferably a main drive torque, so that the motor vehicle is driven exclusively by the drive torque. The transmission arrangement is preferably designed as a planetary gear set, and most preferably as a switchable, particularly two-stage, planetary gear set.

[0029] An electric machine of an axle drive train of the drive system may further comprise a control device. A control device such as that which can be used in the present invention serves in particular for the electronic control and / or regulation of one or more technical systems of one of the electric machines.

[0030] A control device has, in particular, a wired or wireless signal input for receiving signals, especially electrical signals, such as sensor signals. Furthermore, a control device also preferably has a wired or wireless signal output for transmitting signals, especially electrical signals.

[0031] Control operations and / or regulation operations can be performed within the control unit. It is particularly preferred that the control unit comprises hardware configured to execute software. Preferably, the control unit includes at least one electronic processor for executing program sequences defined in software.

[0032] The control unit may also include one or more electronic storage devices in which the data contained in the signals transmitted to the control unit can be stored and read back. Furthermore, the control unit may include one or more electronic storage devices in which data can be stored in a modifiable and / or immutable manner.

[0033] A control system can comprise multiple control units, which are preferably arranged spatially separated from one another within the vehicle. Control units are also referred to as Electronic Control Units (ECUs) or Electronic Control Modules (ECMs) and preferably have electronic microcontrollers for performing calculations and processing data, particularly preferably by means of software. The control units can preferably be networked with each other, enabling wired and / or wireless data exchange between them. In particular, it is also possible to network the control units with each other via bus systems present in the vehicle, such as CAN bus or LIN bus.

[0034] Most preferably, the control device has at least one processor and at least one memory, which in particular contains computer program code, wherein the memory and the computer program code are configured with the processor to cause the control device to execute the computer program code.

[0035] The control unit can particularly preferably comprise power electronics for supplying current to a stator or rotor of an associated electric machine. Power electronics are preferably a combination of various components that control or regulate a current to the electric machine, preferably including the necessary peripheral components such as cooling elements or power supplies. In particular, the power electronics comprise one or more power electronic components configured for controlling or regulating a current. These are particularly preferably one or more power switches, e.g., power transistors. The power electronics particularly preferably have more than two, and more preferably three, separate phases or current paths, each with at least one dedicated power electronic component.The power electronics are preferably designed to control or regulate a power output per phase with a peak power, preferably continuous power, of at least 10 W, preferably at least 100 W, and particularly preferably at least 1000 W.

[0036] An electric motor of an axle drive train of the drive system is preferably dimensioned such that vehicle speeds greater than 50 km / h, preferably greater than 80 km / h, and particularly greater than 100 km / h can be achieved. The electric motor is particularly preferably configured to have a power output greater than 30 kW, preferably greater than 50 kW, and particularly greater than 70 kW. It is further preferred that the electric motor provides rotational speeds greater than 5,000 rpm, particularly preferably greater than 10,000 rpm, and most preferably greater than 12,500 rpm.

[0037] Advantageous embodiments of the invention are specified in the dependent claims. The features listed individually in the dependent claims can be combined in a technologically meaningful manner and can define further embodiments of the invention. Furthermore, the features specified in the claims are specified and explained in more detail in the description, which also presents further preferred embodiments of the invention.

[0038] According to an advantageous embodiment of the invention, it can be provided that a first oil pump is arranged in the first oil sump, which pumps the first oil from the first oil sump to the first electric machine and / or to the first gear arrangement, and / or that a second oil pump is arranged in the second oil sump, which pumps the second oil from the second oil sump to the second electric machine and / or to the second gear arrangement.

[0039] The advantage of this design is that an oil pump in an oil sump can be operated particularly quietly, as it is acoustically isolated or sound-dampened by the surrounding oil.

[0040] According to a further preferred embodiment of the invention, the first drivetrain housing may also define a first gear compartment for accommodating the first gear assembly, from which the first oil can be pumped into the first oil sump via a first oil outlet opening, and / or the second drivetrain housing may define a second gear compartment for accommodating the second gear assembly, from which the second oil can be pumped into the second oil sump via a second oil outlet opening. This achieves a structural separation between the gear compartment and the oil sump. Thus, the gear assembly no longer directly engages with the oil sump, allowing the gear assembly to be operated with minimal churning losses, leading to significant efficiency gains for the respective gear assembly.For example, a spur gear can, if necessary, draw oil accumulating in the gearbox compartment during operation of the transmission assembly into the oil sump via the corresponding oil outlet opening. Maintaining an optimal oil level in the associated oil sump is also easier due to the compartmentalization.

[0041] Furthermore, according to an equally advantageous embodiment of the invention, as already outlined above, it can also be provided that the first gear arrangement has a first gear rotatable parallel to the axis of rotation of the first electric machine, through which the first oil located in the first gear chamber can be conveyed from the first gear chamber through the first oil outlet opening into the first oil sump, and / or the second gear arrangement has a second gear rotatable parallel to the axis of rotation of the second electric machine, through which the second oil located in the second gear chamber can be conveyed from the second gear chamber through the second oil outlet opening into the second oil sump.

[0042] According to a further particularly preferred embodiment of the invention, the first gear may have a first axis of rotation which is arranged in the direction of gravity above the first oil outlet opening, and / or the second gear may have a second axis of rotation which is arranged in the direction of gravity above the second oil outlet opening. This allows, in particular, for a good scooping effect of oil from the gearbox chamber into the corresponding oil sump.

[0043] Furthermore, the invention can also be further developed in such a way that the first gear is sectionally encompassed in the circumferential direction by a channel-like annular segment-shaped first housing section of the first drive train housing and / or the second gear is sectionally encompassed in the circumferential direction by a channel-like annular segment-shaped second housing section of the second drive train housing.

[0044] The advantage of this design is that, on the one hand, splashing losses can be further reduced and, on the other hand, the scooping effect of the corresponding gear can be improved even further.

[0045] In a further preferred embodiment of the invention, the first drivetrain housing and / or the second drivetrain housing can also be designed in multiple parts. This allows for improved adaptability of the drivetrain housing to the available installation space and simultaneously further increases component uniformity through the use of identical housing elements.

[0046] It may also be advantageous to further develop the invention such that the first drivetrain housing comprises a first motor housing for accommodating the first electric machine and a first gearbox housing for accommodating the first gearbox assembly, wherein the first oil sump is formed in and / or on the first gearbox housing, and / or the second drivetrain housing comprises a second motor housing for accommodating the second electric machine and a second gearbox housing for accommodating the second gearbox assembly, wherein the second oil sump is formed in and / or on the second gearbox housing, which can also further increase the commonality of the housing components, since necessary component variants are reduced to the gearbox housings.

[0047] According to a further preferred embodiment of the invention, it can be provided that the first electric machine has a first control unit for supplying current to the first electric machine and the second electric machine has a second control unit for supplying current to the second electric machine, wherein the first control unit and the second control unit are essentially identical in construction, which can also contribute to an increased degree of commonality in the drive system.

[0048] Finally, the invention can also advantageously be implemented such that the first axle drive train comprises two first electric machines arranged coaxially to each other and directly adjacent to one another, each in an axial flux configuration, and / or the second axle drive train comprises two second electric machines arranged coaxially to each other and directly adjacent to one another, each in an axial flux configuration. The advantage resulting from this is, in particular, that a very compact axle drive train can be provided, via which the two vehicle wheels of a vehicle axle can each be driven by an associated electric machine, thus improving the driving dynamics and stability of the drive system.

[0049] The invention will now be explained in more detail with reference to figures, without limiting the general concept of the invention.

[0050] It shows: Fig. 1. A drive system of a motor vehicle with two axle drive trains in a schematic block diagram, Fig. 2 that out Fig. 2 known drive systems with a perspective view of the two axle drive trains, Fig. 3 the first axle drive train in a schematic cross-sectional view, Fig. 4 the second axle drive train in a schematic cross-sectional view.

[0051] The Fig. Figure 1 shows a drive system 1 for a motor vehicle 2 comprising a first axle drive train 4 driving a first vehicle axle 3, housed in a first drive train housing 13, with a first electric machine 5 and a first transmission arrangement 7 forming a first structural unit 6 with the first electric machine 5.

[0052] The drive system 1 further comprises a second axle drive train 9, which drives a second vehicle axle 8 and is housed in a second drive train housing 14, with a second electric machine 10 and a second transmission arrangement 12 forming a second structural unit 11 with the second electric machine 10.

[0053] The first electric machine 5 and the second electric machine 10 as well as the first gear arrangement 7 and the second gear arrangement 12 are essentially identical in construction.

[0054] In the Fig. In the embodiment shown in Figure 1, the first axle drive train 4 has two first electric machines 5 arranged coaxially and directly adjacent to each other, each in an axial flux configuration, and the second axle drive train 9 similarly has two second electric machines 10 arranged coaxially and directly adjacent to each other, each in an axial flux configuration. This allows each wheel of the motor vehicle 2 to be driven by an electric machine 5, 10.

[0055] Due to the different installation space situation at the two vehicle axles 3, 8, the first axle drive train 4 and the second axle drive train 9 are arranged in the drive system 1 rotated at an angle of 10-90° relative to each other with respect to the axes of rotation of the respective electric machines 5, 10, which is particularly evident from the Fig. 2 can be recognized.

[0056] The first drivetrain housing 13 defines a first oil sump 16 containing a first oil 15, while the second drivetrain housing 14 provides a second oil sump 18 containing a second oil 17, the storage volume of the first oil sump 16 corresponding to between 0.75 and 1.25 of the storage volume of the second oil sump 18. The oils 16 and 17 and their fill levels are indicated by a dotted line in the Fig. 3-4 indicated. In the direction of gravity, on the bottom side of the oil sumps 16,18, a first oil drain opening 36 and a second oil drain opening 35 are provided, respectively.

[0057] From the Fig. 3-4 further shows that in the first oil sump 16 a first oil pump 33 is arranged, which pumps the first oil 15 from the first oil sump 16 to the first electric machine 5 and to the first gear arrangement 7. And in the second oil sump 18 a second oil pump 19 is arranged, which pumps the second oil 17 from the second oil sump 18 to the second electric machine 10 and to the second gear arrangement 12.

[0058] The first drivetrain housing 13 defines a first gear compartment 20 for receiving the first gear assembly 7 from which the first oil 15 can be conveyed via a first oil outlet opening 21 into the first oil sump 16, which in the Fig. 3 is shown. Similarly, in the Fig. Figure 4 shows that the second drive train housing 14 defines a second gearbox compartment 22 for receiving the second gearbox assembly 12, from which the second oil 17 can be pumped into the second oil sump 18 via a second oil outlet opening 23.

[0059] The first gear assembly 7 further comprises a first gear 34 rotatable parallel to the axis of rotation of the first electric machine 5, through which the first oil 15 located in the first gear chamber 20 can be conveyed from the first gear chamber 20 through the first oil outlet opening 21 into the first oil sump 16. The second gear assembly 12 also comprises a second gear 24 rotatable parallel to the axis of rotation of the second electric machine 10, through which the second oil 17 located in the second gear chamber 22 can be conveyed from the second gear chamber 22 through the second oil outlet opening 23 into the second oil sump 18.

[0060] The first gear 34 also has a first axis of rotation, which is arranged in the direction of gravity above the first oil outlet opening 21. The second gear 24 also has a second axis of rotation, which is arranged in the direction of gravity above the second oil outlet opening 23, as can again be clearly seen from the overall view of the Fig. 3-4 can be identified.

[0061] In the Fig. Figure 3 further shows that the first gear 34 is circumferentially encompassed by a channel-like, annular-section-shaped first housing section 25 of the first drive train housing 13, while, as shown in the Fig. Figure 4 shows that the second gear 24 is also partially enclosed in the circumferential direction by a channel-like, annular-shaped second housing section 26 of the second drive train housing 14.

[0062] Thus, one can see from the examples of the implementation of the Fig. 3-4 also shows how the separation of the installation space between the oil sumps 16,18 and the gearbox rooms 20,22 can be designed.

[0063] Also in the Fig. Figure 3 shows that the first drivetrain housing 13 comprises a first motor housing 27 for receiving the first electric machine 5 and a first gearbox housing 28 for receiving the first gearbox assembly 7, wherein the first oil sump 16 is formed in and / or on the first gearbox housing 28. The second drivetrain housing 14 similarly comprises a second motor housing 29 for receiving the second electric machine 10 and a second gearbox housing 30 for receiving the second gearbox assembly 12, wherein the second oil sump 18 is formed in and / or on the second gearbox housing 30, as shown in Figure 3. Fig. 4 can be removed.

[0064] It is evident from the Fig. 3 furthermore, that the first electric machine 5 has a first control unit 31 for supplying current to the first electric machine 5 and the second electric machine 10 which is in the Fig. Figure 4 shows a second control unit 32 for supplying current to the second electric machine 10, wherein the first control unit 31 and the second control unit 32 are essentially identical in construction.

[0065] The terms radial, axial, tangential, and circumferential direction used in this application always refer to the axis of rotation of the corresponding electrical machine. The terms left, right, top, bottom, above, and below serve only to clarify which areas of the figures are currently being described in the text. Later embodiments of the invention may be arranged differently. Furthermore, the invention is not limited to the embodiments shown in the figures. The foregoing description is therefore not to be considered limiting, but rather explanatory. The following claims are to be understood as meaning that a named feature is present in at least one embodiment of the invention. This does not preclude the presence of further features.If the patent claims and the preceding description define 'first' and 'second' feature, this designation serves to distinguish between two similar features without establishing a hierarchy. Reference symbol list 1 Drive system 2 motor vehicles 3 first vehicle axle 4 first axle drive train 5 first electric machine 6 units 7 first gear arrangement 8 second vehicle axle 9 second axle drive train 10 second electric machine 11 Unit 12 second gear arrangement 13 first drivetrain housing 14 second drivetrain housing 15 first oil 16 first oil sump 17 second oil 18 second oil sump 19 second oil pump 20 first gearbox compartment 21 first oil outlet opening 22 second gearbox compartment 23 second oil outlet opening 24 second gear 25 first housing section 26 second housing section 27 first engine casing 28 first gearbox housing 29 second engine casing 30 second gearbox housing 31 first control unit 32 second control unit 33 first oil pump 34 first gear 35 second oil drain opening 36 first oil drain opening QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 102010048837 A1

[0004]

Claims

[1] Propulsion system (1) for a motor vehicle (2) comprising a first axle drive train (4) driving a first vehicle axle (3) housed in a first drive train housing (13) with a first electric machine (5) and a first gear arrangement (7) forming a first structural unit (6) with the first electric machine (5) and a second axle drive train (9) driving a second vehicle axle (8) housed in a second drive train housing (14) with a second electric machine (10) and a second gear arrangement (12) forming a second structural unit (11) with the second electric machine (10), wherein the first electric machine (5) and the second electric machine (10) as well as the first gear arrangement (7) and the second gear arrangement (12) are essentially identical in construction, characterized by , that the first axle drive train (4) and the second axle drive train (9) are arranged in the drive system (1) rotated by an angle of 10-90° relative to each other with respect to the axes of rotation of the respective electric machines (5, 10), and the first powertrain housing (13) defines a first oil sump (16) containing a first oil (15), and the second drivetrain housing (14) defines a second oil sump (18) containing a second oil (17), wherein the absorption volume of the first oil sump (16) corresponds to between 0.75-1.25 of the absorption volume of the second oil sump (18). [2] Drive system (1) according to claim 1, characterized by , that a first oil pump (33) is arranged in the first oil sump (16), which pumps the first oil (15) from the first oil sump (16) to the first electric machine (5) and / or to the first gear assembly (7). and / or a second oil pump (19) is arranged in the second oil sump (18), which pumps the second oil (17) from the second oil sump (18) to the second electric machine (10) and / or to the second gear arrangement (12). [3] Drive system (1) according to any one of the preceding claims, characterized by , that the first drivetrain housing (13) defines a first gear compartment (20) for receiving the first gear assembly (7), from which the first oil (15) can be conveyed via a first oil outlet opening (21) into the first oil sump (16) and / or the second drivetrain housing (14) defines a second transmission chamber (22) for receiving the second transmission assembly (12), from which the second oil (17) can be conveyed via a second oil outlet opening (23) into the second oil sump (18). [4] Drive system (1) according to claim 3, characterized by , that the first gear arrangement (7) has a first gear (34) rotatable parallel to the axis of rotation of the first electric machine (5), through which the first oil (15) located in the first gear chamber (20) can be conveyed from the first gear chamber (20) through the first oil outlet opening (21) into the first oil sump (16). and / or the second gear arrangement (12) has a second gear (24) rotatable parallel to the axis of rotation of the second electric machine (10), through which the second oil (17) located in the second gear chamber (22) can be conveyed from the second gear chamber (22) through the second oil outlet opening (23) into the second oil sump (18). [5] Drive system (1) according to claim 3 or 4, characterized by , that the first gear (34) has a first axis of rotation which is arranged in the direction of gravity above the first oil outlet opening (21) and / or the second gear (24) has a second axis of rotation which is arranged in the direction of gravity above the second oil outlet opening (23). [6] Drive system (1) according to any one of the preceding claims, characterized by , that the first gear (34) is sectionally enclosed in the circumferential direction by a channel-like annular segment-shaped first housing section (25) of the first drive train housing (13). and / or the second gear (24) is enclosed section by section in the circumferential direction by a channel-like annular segment-shaped second housing section (26) of the second drive train housing (14). [7] Drive system (1) according to any one of the preceding claims, characterized by , that the first drive train housing (13) is designed in multiple parts and / or the second drive train housing (14) is designed in multiple parts. [8] Drive system (1) according to any one of the preceding claims, characterized by , that the first drivetrain housing (13) comprises a first motor housing (27) for receiving the first electric machine (5) and a first gearbox housing (28) for receiving the first gearbox assembly (7), wherein the first oil sump (16) is formed in and / or on the first gearbox housing (28) and / or the second drive train housing (14) comprises a second motor housing (29) for receiving the second electric machine (10) and a second gearbox housing (30) for receiving the second gearbox assembly (12), wherein the second oil sump (18) is formed in and / or on the second gearbox housing (30). [9] Drive system (1) according to any one of the preceding claims, characterized by, that the first electric machine (5) has a first control unit (31) for supplying current to the first electric machine (5) and the second electric machine (10) has a second control unit (32) for supplying current to the second electric machine (10), wherein the first control unit (31) and the second control unit (32) are essentially identical in construction. [10] Drive system (1) according to any one of the preceding claims, characterized by , that the first axle drive train (4) comprises two first electrical machines (5) arranged coaxially to each other, axially directly adjacent to each other, each in an axial flux configuration and / or the second axle drive train (9) comprises two second electrical machines (10) arranged coaxially to each other, axially directly adjacent to each other, each in an axial flux configuration.

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