Electric drive system for a motor vehicle and method for operating such an electric drive system

Abstract

The invention relates to an electric drive system (10) for a motor vehicle, comprising a first electric machine (22) having a first rotor (24), a second electric machine (34) having a second rotor (36) arranged coaxially with the first rotor (24), a first vehicle wheel (14) which can be driven by means of the first rotor (24), a second vehicle wheel (16) which can be driven by means of the second rotor (36), and a first coupling (L1) configured to couple the second rotor (36) to the first vehicle wheel (14) in a torque-transmitting manner. A second coupling (L2) is provided, configured to couple the second rotor (36) to the second vehicle wheel (16) in a torque-transmitting manner. A third coupling (K) is provided, configured to couple the first rotor (24) to the first vehicle wheel (14) in a torque-transmitting manner.

Description

[0001] The invention relates to an electric drive system for a motor vehicle, in particular for a motor vehicle, according to the preamble of patent claim 1. Furthermore, the invention relates to a method for operating such an electric drive system.

[0002] DE 10 2021 128 898 A1 discloses a drive train device for a vehicle.

[0003] The object of the present invention is to provide an electric drive system for a motor vehicle and a method for operating such an electric drive system, so that a particularly advantageous operation of the electric drive system can be realized.

[0004] This object is achieved by an electric drive system having the features of patent claim 1 and by a method having the features of patent claim 8. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0005] A first aspect relates to an electric drive system, also referred to as an electric drive device or electric drive unit, or designed as an electric drive device or electric drive unit, for a motor vehicle, also simply referred to as a vehicle. This means that the motor vehicle, preferably designed as a motor vehicle, in particular as a passenger car, has the electric drive system in its fully manufactured state and can be driven, in particular purely electrically, by means of the electric drive system.

[0006] The electric drive system has a first electric machine having a first rotor. In particular, the first electric machine has a first stator, by means of which the first rotor can be driven and is thus rotatable about a first motor axis of rotation relative to the first stator. The electric drive system also has a second electric machine, which is provided in addition to the first electric machine and has a second rotor. In particular, the second electric machine has a second stator, by means of which the second rotor can be driven and is thus rotatable about a second motor axis of rotation relative to the second stator. The second rotor is arranged coaxially to the first rotor, so that the machine axes of rotation coincide.Thus, the machine axes of rotation coincide with a main axis of rotation of the electric drive system, whose axial direction runs along the main axis of rotation or coincides with the main axis of rotation. The respective rotor can rotate about the main axis of rotation relative to the respective stator.

[0007] The electric drive system has a first vehicle wheel and a second vehicle wheel. The first vehicle wheel can be driven by the first rotor, in particular bypassing the second vehicle wheel, and the second vehicle wheel can be driven by the second rotor, in particular bypassing the first vehicle wheel. For example, in its fully manufactured state, the motor vehicle has at least or exactly two vehicle axles arranged consecutively and thus one behind the other in the longitudinal direction of the motor vehicle, namely a first vehicle axle and a second vehicle axle. The vehicle axles are also simply referred to as axles. The respective vehicle axle has at least or exactly two vehicle wheels.In this case, it is preferably provided that the first vehicle wheel and the second vehicle wheel are the vehicle wheels of the same vehicle axle, so that, for example, the vehicle axle or the second vehicle axle has the first vehicle wheel and the second vehicle wheel. When reference is made above and below to the vehicle wheels, this means the first vehicle wheel and the second vehicle wheel, unless otherwise stated. Very particularly, the vehicle wheels of the respective vehicle axle are arranged on opposite sides of the motor vehicle in the transverse direction of the motor vehicle. The vehicle wheels of the motor vehicle and thus the first vehicle wheel and the second vehicle wheel are ground contact elements of the motor vehicle, which can be or is supported on the ground towards the rear in the vertical direction of the motor vehicle via the ground contact elements.If the motor vehicle is driven along the ground while supported vertically and downwards by the ground contact elements, the ground contact elements roll, particularly directly, along the ground. The first and second vehicle wheels are also referred to as wheels or drive wheels.

[0008] The feature that the first vehicle wheel can be driven by means of the first rotor, bypassing the second vehicle wheel, is to be understood as meaning that the first rotor can provide a first drive torque, by means of which the first vehicle wheel can be driven, in particular bypassing the second vehicle wheel, wherein, with respect to a first torque flow along which the first drive torque can be transmitted from the first rotor to the first vehicle wheel in order to thereby drive the vehicle wheel, the second vehicle wheel is not arranged downstream of the first rotor and upstream of the first vehicle wheel in the first torque flow.Accordingly, the feature that the second vehicle wheel can be driven by means of the second rotor, bypassing the first vehicle wheel, is to be understood as meaning that the second rotor can provide a second drive torque by means of which the second vehicle wheel can be driven, wherein, with respect to a second torque flow along which the second drive torque can be transmitted from the second rotor to the second vehicle wheel in order to thereby drive the second vehicle wheel, the first vehicle wheel is not arranged downstream of the second rotor and upstream of the second vehicle wheel in the second torque flow. In particular, by driving the respective rotor, the respective vehicle wheel can be driven by means of the respective rotor.

[0009] The electric drive system further comprises a first clutch, which is designed to couple the second rotor to the first vehicle wheel in a torque-transmitting, in particular rotationally fixed, manner. In other words, the second rotor can be coupled, i.e. connected, to the first vehicle wheel by means of the first clutch in a torque-transmitting, in particular rotationally fixed, manner. For this purpose, the first clutch can be switched, for example, between a first coupling state and a first decoupling state. In the first coupling state, the second rotor is coupled, i.e. connected, to the first vehicle wheel by means of the first clutch in a torque-transmitting, in particular rotationally fixed, manner. In the first decoupling state, the second rotor is decoupled from the first vehicle wheel, such that in particular no torque can be transmitted via the first clutch to the second rotor on the first vehicle wheel.

[0010] In order to be able to realize particularly advantageous operation of the electric drive system, it is provided according to the invention that the electric drive system has a second clutch provided in addition to the first clutch, which is designed to couple, i.e. connect, the second rotor to the second vehicle wheel in a torque-transmitting, in particular rotationally fixed, manner. In other words, by means of the second clutch, the second rotor can be coupled, i.e. connected, to the second wheel in a torque-transmitting, in particular rotationally fixed, manner. Thus, for example, the second clutch can be switched between a second coupling state and a second decoupling state. In the second coupling state, the second rotor is coupled, i.e. connected, to the second vehicle wheel in a torque-transmitting, in particular rotationally fixed, manner.In the second decoupling state, the second rotor is decoupled from the second vehicle wheel, so that, in particular, no torque can be transmitted between the second rotor and the second vehicle wheel via the second clutch.

[0011] According to the invention, the drive system further comprises a third clutch provided in addition to the first clutch and in addition to the second clutch, which third clutch is designed to couple, i.e. connect, the first rotor to the first vehicle wheel in a torque-transmitting, in particular rotationally fixed, manner. In other words, by means of the third clutch, the first rotor can be coupled, i.e. connected, to the first vehicle wheel in a torque-transmitting, in particular rotationally fixed, manner. The third clutch can be switched, for example, between a third coupling state and a third decoupling state. In the third coupling state, the first rotor is coupled, i.e. connected, to the first vehicle wheel in a torque-transmitting, in particular rotationally fixed, manner.In the third decoupling state, the first rotor is decoupled from the first vehicle wheel, so that, for example, no torque can be transmitted via the third clutch between the first rotor and the first vehicle wheel. The following is also conceivable: In the first coupling state, for example by means of the first clutch, the second rotor is coupled to the first vehicle wheel in a torque-transmitting, in particular rotationally fixed, manner such that at most a first torque can be transmitted via the first clutch, in particular between the second rotor and the first vehicle wheel, wherein the first torque is greater than zero in terms of amount, i.e. in terms of its magnitude. In the first decoupling state, for example, no torque can be transmitted via the first clutch because, for example, in the first decoupling state, the first clutch is fully disengaged.Furthermore, it is conceivable that in the second decoupling state, the second rotor is coupled to the first vehicle wheel by means of the first clutch in such a torque-transmitting manner that in the first decoupling state, at most a second torque can be transmitted via the first clutch and in particular between the second rotor and the first vehicle wheel, wherein the second torque is less in magnitude, i.e., in terms of its magnitude, than the first torque and wherein the second torque is greater in magnitude, i.e., in terms of its magnitude, than zero. The previous and following statements regarding the first clutch can also be readily applied to the second clutch and the third clutch.Thus, it is conceivable, for example, that in the second coupling state, the second rotor is coupled to the second vehicle wheel by means of the second clutch in such a torque-transmitting manner that at most a third torque can be transmitted via the second clutch, in particular between the second rotor and the second vehicle wheel, wherein the third torque is greater than zero in magnitude. It is conceivable that in the second decoupling state, no torque can be transmitted via the second clutch, so that, for example, the second clutch is fully disengaged.Alternatively, it is conceivable that in the second decoupling state, the second rotor is coupled to the second vehicle wheel in a torque-transmitting manner by means of the second clutch in such a way that at most a fourth torque can be transmitted via the second clutch and in particular between the second rotor and the second vehicle wheel, wherein the fourth torque is smaller in magnitude, i.e. in terms of its amount, than the third torque and wherein the fourth torque is greater than zero in magnitude, i.e. in terms of its amount. Furthermore, it is provided, for example, that in the third coupling state, the first rotor is coupled to the first vehicle wheel in a torque-transmitting manner by means of the third clutch in such a way that at most a fifth torque can be transmitted via the third clutch and in particular between the first rotor and the first vehicle wheel, which fifth torque is greater than zero in magnitude, i.e. in terms of its amount.It is conceivable that in the third decoupling state no torque can be transmitted via the third clutch, so that, for example, the third clutch is fully open. Alternatively, it is conceivable that in the third decoupling state the first rotor is coupled to the first vehicle wheel in a torque-transmitting manner by means of the third clutch such that at most a sixth torque can be transmitted via the third clutch and in particular between the first rotor and the first vehicle wheel, which torque is greater than zero in terms of amount, i.e. in terms of its magnitude, wherein the sixth torque is less than the fifth torque in terms of amount, i.e. in terms of its magnitude. Preferably, the clutches are arranged outside of one another when viewed in pairs. By using the three clutches, a particularly needs-based operation of the drive system can be achieved.For example, it is conceivable that in a first operating mode of the drive system the first clutch and the second clutch are closed simultaneously, thus that the first clutch is in the first coupling state and the second clutch is in the second coupling state, in particular while the third clutch is open, thus while the third clutch is in the third decoupling state. The vehicle wheels can then be driven by means of the second rotor, in particular while the vehicle wheels are not driven by the first rotor. Thus, in the first operating mode the first rotor is decoupled from the vehicle wheels, while the second rotor is coupled to the vehicle wheels via the first clutch and the second clutch in a torque-transmitting manner.Thus, the first operating mode is, for example, a single-machine operation in which, with respect to the electric machine, the vehicle wheels can be or are driven exclusively by means of the second electric machine, i.e. by means of the second rotor, i.e. while driving the vehicle wheels by means of the first rotor, i.e. by means of the first electric machine, does not occur. This makes it possible to achieve particularly energy-efficient operation. In a second operating mode, for example, the second clutch and the third clutch are closed, i.e., for example, the second clutch is in a second coupling state and the third clutch is in the third coupling state, while the first clutch is open, i.e., while the first clutch is in its first decoupling state.The first rotor and thus the first electric machine can then drive the first vehicle wheel, in particular by bypassing the second vehicle wheel, and the second rotor and thus the second electric machine can drive the second vehicle wheel, in particular bypassing the first vehicle wheel. The second operating mode is thus a two-machine operation, in which, for example, a high top speed and / or strong acceleration of the motor vehicle can be achieved. Since the clutches can be switched between the coupled and uncoupled states as needed, switching between the first operating mode and the second operating mode is possible as needed, so that a needs-based and advantageous operation of the drive system can be achieved.

[0012] In order to realize particularly advantageous operation of the drive system in a particularly space-efficient manner, one embodiment of the invention provides that the vehicle wheels are arranged at least substantially coaxially with the rotors. This means that the vehicle wheels are either arranged strictly coaxially with the rotors, so that a respective wheel axis of rotation, about which the respective wheel is rotatable relative to the respective stator, coincides with the main axis of rotation, or the vehicle wheels have a slight, i.e., small, axial offset from the rotors, so that, for example, the respective wheel axis of rotation runs parallel to the main axis of rotation and is spaced from the main axis of rotation, or so that the respective wheel axis of rotation runs obliquely to the main axis of rotation.The said axle offset can be realized, for example, by a respective intermediate cardan shaft, which is arranged, for example, with respect to the respective torque flow between the respective rotor and the respective vehicle wheel, so that, for example, the respective vehicle wheel can be driven by the respective rotor via the respective cardan shaft.

[0013] A further embodiment is characterized in that, with regard to an axial direction of the drive system, i.e. viewed in the axial direction of the electric drive system and thus along the main axis of rotation, the first rotor, the third clutch, the first clutch and the second rotor are arranged in the order in which they are mentioned, i.e. one after the other, in the following order: the first rotor - the third clutch - the first clutch - the second rotor. This means that, viewed in the axial direction of the electric drive system and thus along the main axis of rotation, the third clutch follows the first rotor, the first clutch follows the third clutch and the second rotor follows the first clutch. This enables particularly advantageous operation in a particularly space-saving manner.

[0014] In the context of the present invention, the term “axial” is to be understood as the axial direction of the electric drive system, the radial direction of which is perpendicular to the axial direction of the electric drive system. In other words, the term “axial” means the axial direction of the electric drive system. In other words, “axial” refers to the axial direction of the electric drive system. In the context of the present disclosure, the term “radial” refers to the radial direction of the electric drive system. In other words, the term “radial” means the radial direction of the drive system. Thus, “radial” refers to the radial direction of the drive system. When reference is made above and below to the axial direction, this means the axial direction of the drive system, unless otherwise stated.When reference is made to the radial direction above and below, this refers to the radial direction of the electric drive system, unless otherwise stated.

[0015] In the context of the present disclosure, the feature that two components are connected to one another in a rotationally fixed manner is to be understood as meaning that the components connected to one another in a rotationally fixed manner are arranged coaxially to one another and, in particular when the components are driven, rotate together or simultaneously about a component rotation axis common to the components, such as the main rotation axis, at the same angular velocity, in particular relative to a reference element, such as a housing of the drive system. It is conceivable that at least one of the rotors is at least partially arranged in the housing. In other words, two elements are connected to one another in a rotationally fixed manner if they are arranged coaxially to one another, in particular with respect to their component rotation axis or with respect to a rotational symmetry axis, and if they are connected to one another in such a way that they always rotate at the same angular velocity.An element is connected to the housing in a rotationally fixed manner if it cannot be rotated relative to the housing. The feature that two components are connected or coupled to one another in a torque-transmitting manner means that the components are coupled or connected to one another in such a way that torque can be transmitted between the components. If the components are connected or coupled to one another in a rotationally fixed manner, the components are also connected or coupled to one another in a torque-transmitting manner. Two components connected to one another in a torque-transmitting manner can thus be connected to one another in a rotationally fixed manner.Furthermore, it is conceivable that two components connected to one another in a torque-transmitting manner are connected to one another in a torque-transmitting manner via an intermediate transmission unit, so that torques can be transmitted between the components via the transmission unit, while the components are connected to one another in a torque-transmitting manner, whereby, however, the components can be rotatable relative to one another.The feature that two components are permanently connected or coupled to one another in a torque-transmitting manner does not mean that a screw element is provided that can be switched between a coupling state that connects or couples the components to one another in a torque-transmitting manner and a decoupling state in which no torque can be transmitted between the components via the screw element. Rather, the components are always and therefore permanently torque-transmitting, i.e., connected or coupled to one another in such a way that torque can be transmitted between the components. Thus, for example, one of the components can be driven by the other component, and vice versa.

[0016] In particular, the feature that two components are permanently connected or coupled to one another in a rotationally fixed manner is to be understood as meaning that a screw element is not provided which can be switched between a coupling state which connects or couples the components to one another in a rotationally fixed manner and a decoupling state in which the components are decoupled from one another and can be rotated relative to one another so that no torque can be transmitted between the components via the switching element, but rather the components are always connected or coupled to one another, thus in a rotationally fixed manner.

[0017] Furthermore, the feature that two components can be connected or coupled to one another in a rotationally fixed manner means that a switching element, such as the respective clutch, is assigned to the components, wherein the switching element can be switched between at least one coupling state and at least one decoupling state. In the coupling state, the components are connected or coupled to one another in a rotationally fixed manner by means of the switching element. In the decoupling state, the components are decoupled from one another, so that in the decoupling state the components can be rotated relative to one another about the component rotation axis. The same applies to the feature that two components can be connected or coupled to one another in a torque-transmitting manner.Thus, the feature that two components can be connected or coupled to one another in a torque-transmitting manner is understood to mean that a switching element is assigned to the components, wherein the switching element can be switched between at least one connected state and at least one released state. In the connected state, the components are coupled or connected to one another in a torque-transmitting manner by means of the switching element, so that torque can be transmitted between the components, in particular via the switching element. In the released state, the components are decoupled from one another, so that in the released state, no torque can be transmitted between the components via the switching element.

[0018] In order to be able to realize a particularly advantageous operation in a particularly space-saving manner, it is provided in a further embodiment of the invention that the second clutch is arranged axially overlapping the first clutch.

[0019] A further embodiment is characterized in that the second clutch is arranged between the first clutch and the second rotor in the axial direction of the drive system, whereby the installation space requirement can be kept particularly low.

[0020] In another particularly advantageous embodiment of the invention, the first clutch and the second clutch are each designed as a multi-plate clutch. The multi-plate clutches can together replace or form a differential gear, thus eliminating the need for a differential gear in addition to the clutches. Particularly in single-engine operation, differential speeds between the vehicle wheels are possible, or such differential speeds can be permitted, for example, by operating the first clutch and / or the second clutch with slippage, particularly in single-engine operation.

[0021] In order to be able to realize a particularly energy-efficient operation, it is provided in a further embodiment of the invention that the third clutch is designed as a claw clutch and thus as a positive-locking clutch.

[0022] A second aspect of the invention relates to a method for operating an electric drive system according to the first aspect of the invention. Advantages and advantageous embodiments of the first aspect of the invention are to be regarded as advantages and advantageous embodiments of the second aspect of the invention, and vice versa.

[0023] In order to be able to realize particularly advantageous operation of the drive system, one embodiment of the second aspect of the invention provides that for or in single-motor operation of the electric drive system, the first clutch and the second clutch are each operated in a closed position, in particular with variable slip. In particular, the respective closed position of the respective clutch is the respective coupling state of the respective clutch, so that, for example, in or for single-motor operation, the first clutch is in the first coupling state and the second clutch is in the second coupling state, in particular while the third clutch is in the third uncoupling state.The feature that the first clutch and / or the second clutch is operated with variable slip in its respective closed position means that a slip of the first clutch and / or the second clutch is variable or is varied. In other words, different values ​​of a respective slip of the respective first or second clutch can be set, wherein, for example, in particular exactly, one of the values ​​is zero, so that the respective clutch is operated without slip, and wherein, for example, at least one further value or several further values ​​are different from zero, but in particular greater than zero, so that the respective clutch is operated with slip. As a result, different speeds of the vehicle wheels can be permitted, as described above, so that the first clutch and the second clutch can function as a differential gear.This eliminates the need for an additional, separate differential gear, allowing for a particularly space-saving, cost-effective, and lightweight drive system design. In particular, single-motor operation, for example, is the aforementioned single-machine operation.

[0024] In order to be able to realize particularly advantageous operation, it is provided in a further embodiment of the second aspect of the invention that for or in a two-motor operation of the electric drive system, the third clutch and the second clutch are each operated in a fully closed position, in particular while the first clutch is open. In other words, it is therefore preferably provided that in or for the two-motor operation, the third clutch is in the third coupling state and the second clutch is in the second coupling state, in particular while the first clutch is in the first decoupling state. It is preferably provided that the third clutch and the second clutch are operated slip-free, i.e. without slip. Thus, for example, the two-motor operation is the aforementioned two-machine operation.One-machine operation is also called single-machine operation or single mode, and two-machine operation is also called dual mode, for example.

[0025] Preferably, an electromechanical actuator is used for the respective clutch, in particular for the respective multi-plate clutch, so that, for example, the respective clutch can be switched between the respective coupling state and the respective decoupling state by means of the respective, assigned electromechanical actuator. The electromechanical actuator is preferably designed to be self-locking or self-holding, which is particularly advantageous compared to a hydraulic actuation, so that, for example, with regard to the respective coupling state and the respective decoupling state, which are collectively also referred to as states of the respective clutch, at least one of the states or both states can be held, in particular by means of the respective actuator, without supplying the actuator with energy. This can ensure particularly efficient operation.

[0026] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective specified combinations, but also in other combinations or on their own, without departing from the scope of the invention.

[0027] The drawing shows: Fig. 1 is a schematic representation of an electric drive system for a motor vehicle; and Fig. 2 a switching table to illustrate different operating modes of the electric drive system.

[0028] In the figures, identical or functionally identical elements are provided with the same reference symbols.

[0029] Fig. Figure 1 shows a schematic representation of an electric drive system 10 for a motor vehicle, also referred to simply as a vehicle. The motor vehicle, preferably designed as a motor vehicle, in particular as a passenger car, has at least or exactly two vehicle axles arranged one behind the other in the longitudinal direction of the motor vehicle, namely a first vehicle axle and a second vehicle axle. The first vehicle axle is in Fig. 1 and designated 12. The first vehicle axle 12 can be part of the electric drive system 10. The previous and following statements regarding the first vehicle axle 12 can also be readily applied to the second vehicle axle, and vice versa.

[0030] Out of Fig. 1 that the vehicle axle 12 has exactly two vehicle wheels, namely a first vehicle wheel 14 and a second vehicle wheel 16. The vehicle wheels 14 and 16 are ground contact elements of the motor vehicle, which can be or is supported downwards on a ground via the ground contact elements in the vertical direction of the motor vehicle. The vertical direction of the vehicle is illustrated by a double arrow 18. The vehicle wheels 14 and 16 are arranged on opposite sides of the motor vehicle in the transverse direction of the motor vehicle, wherein the transverse direction of the vehicle is illustrated by a double arrow 20.

[0031] The electric drive system 10 has a first electric machine 22, which comprises a first rotor 24 and a first stator 26. For example, the drive system 10 has a particularly schematically illustrated housing 28. The rotor 24 can be driven by means of the stator 26 and can therefore be rotated about a first motor axis of rotation relative to the stator 26 and relative to the housing 28. In the present case, the first electric machine 22 is designed as a first axial flux machine, the rotor 24 of which has two rotor elements 30 and 32 that are spaced apart from one another in the axial direction of the electric machine 22 and thus along the first machine axis of rotation. The stator 26 is arranged between the rotor elements 30 and 32 in the axial direction of the electric machine 22.

[0032] The electric drive system 10 has a second electric machine 34 provided in addition to the first electric machine 22. The second electric machine 34 has a second rotor 36 and a second stator 38. The respective stator 26, 38 is, for example, at least indirectly connected in a rotationally fixed manner to the housing 28. The rotor 36 can be driven by the stator 38 and can thus be rotated about a second motor axis of rotation relative to the stator 38 and relative to the housing 28. In the exemplary embodiment shown in the figures, the second electric machine 34 is also designed as a second axial flux machine. The second axial flux machine, i.e. its rotor 36, has two rotor elements 40 and 42, which are spaced apart from one another in the axial direction of the electric machine 34 and thus along the second machine axis of rotation. The stator 38 is arranged between the rotor elements 40 and 42.The rotor elements 30 and 32 or 40 and 42 are preferably disc-shaped.

[0033] The electric machines 22 and 36 are arranged coaxially to one another so that the machine axes of rotation coincide and so that the machine axes of rotation coincide with a main axis of rotation of the drive system 10, the axial direction of which coincides with the main axis of rotation.

[0034] By means of the rotor 24, the vehicle wheel 14 can be driven, in particular by bypassing the vehicle wheel 16, and by means of the rotor 36, the vehicle wheel 16 can be driven, in particular by bypassing the vehicle wheel 14. It can be seen from Fig. 1 also shows that the vehicle wheels 14 and 16 are the vehicle wheels of the same vehicle axle 12. The electric drive system 10 has a first clutch L1, by means of which the second rotor 36 can be coupled to the first vehicle wheel 14 in a torque-transmitting manner.

[0035] In order to realize particularly advantageous operation of the drive system 10, the electric drive system 10 also has a second clutch L2 provided in addition to the first clutch L1, by means of which the second rotor 36 can be coupled to the second vehicle wheel 16 in a torque-transmitting manner. The electric drive system 10 also has a third clutch K, by means of which the first rotor 24 can be coupled, i.e., connected, to the first vehicle wheel 14 in a torque-transmitting manner.

[0036] Fig. Figure 2 shows a switching table illustrating two operating modes of the electric drive system 10, which can be operated in the operating modes. In a method for operating the electric drive system 10, it is thus provided, for example, that the drive system 10 is operated in a first of the operating modes during at least a first period of time and in a second of the operating modes during at least a second period of time. The first operating mode is also referred to as single-machine operation or single-motor operation SM. Fig. 2 it can be seen that for and in single-engine operation the third clutch K is open, while clutches L1 and L2 are closed. Thus, clutch K is in its uncoupled state, while the respective clutch L1, L2 is in its respective coupled state. In the single-engine operation SM, the respective clutch L1, L2 is operated with variable slip, so that, for example, during at least part of the single-engine operation SM, at least one of the clutches L1 and L2 is operated with a slip that is greater in magnitude than zero. Through this slipping operation, i.e. through operation with variable slip, different speeds of the vehicle wheels 14 and 16 can be permitted, so that the clutches L1 and L2, considered together, function or operate as a differential gear. Thus, an additional, separate differential gear can be avoided.

[0037] The second operating mode is dual-engine operation (DM), also known as dual-machine operation. For and in dual-engine operation (DM), clutches K and L2 are closed, while clutch L1 is open. Thus, for example, clutches K and L2 are in their respective coupled states, while clutch L1 is in its uncoupled state. In dual-engine operation (DM), clutch L2 is preferably fully closed and thus operated without slippage. Clutch K is also fully closed and thus operated without slippage in dual-engine operation (DM).

[0038] The respective slipping operation of the respective clutch L1, L2 can be realized in particular by the fact that, in the exemplary embodiment shown in the figures, the respective clutch L1, L2 is designed as a respective multi-disk clutch and thus as a respective friction clutch. In contrast, in the exemplary embodiment shown in the figures, the clutch K is designed as a claw clutch, thus as a positive-locking clutch.

[0039] The vehicle wheels 14 and 16 are arranged, for example, at least substantially coaxially with the rotors 24 and 36. In the axial direction of the electric drive system 10, whose radial direction is perpendicular to the axial direction of the electric drive system 10, the first rotor 24, the third clutch K, the first clutch L1, and the second rotor 36 are arranged in the order in which they are mentioned, thus in the following sequence: the first rotor - the third clutch K - the first clutch L1 - the second rotor 36. The axial direction of the drive system 10 coincides with the main axis of rotation.

[0040] In order to realize a particularly compact design, in particular in the axial direction of the drive system 10, it can be provided that the second clutch L2 is arranged axially overlapping the first clutch L1, so that, for example, the clutches L1 and L2 can be arranged radially nested in one another in the axial direction of the drive system 10.

[0041] In the embodiment shown in the figures, however, it is provided that in the axial direction of the electric drive system 10 the second clutch L2 is arranged, in particular completely, between the first clutch L1 and the second rotor 36.

[0042] In Fig. 2, the fully engaged position of the respective clutch K, L1, L2 is indicated by "X". The fully engaged position means that the respective clutch K, L1, L2 is in its respective coupling state and is actuated without slip, and is therefore slip-free. "XS" in Fig.2 illustrates a respective further closed position of the respective clutch L1, L2, wherein the respective further closed position is a slipping closed position or a further closed position with variable slip, such that the respective clutch L1, L2 is operated in a slipping and / or variable slip manner in its respective further closed position, at least temporarily, in particular at least during part of a cornering movement of the motor vehicle. In other words, again, the respective clutch L1, L2 is in its respective coupled state in its respective further closed position, but exhibits slip, and is therefore operated in a slipping manner or with variable slip. Thus, in the respective fully closed position, any slippage of the respective clutch L1, L2 is prevented.In the respective further closed position, however, at least temporarily, in particular at least during part of a cornering of the motor vehicle, a slip of the respective clutch L1, L2 is permitted or at least one of the clutches L1, L2 is operated with a slip that is greater than 0, whereby, for example, different speeds of the vehicle wheels 14, 16 are permitted when cornering, so that the clutches L1 and L2 function or operate together as a differential gear or work or function in the manner of a differential gear, in particular such that the vehicle wheel 14, 16 on the outside of the curve rotates at a higher speed than the vehicle wheel 16, 14 on the inside of the curve. List of reference symbols 10 electric drive system 12 vehicle axles 14 first vehicle wheel 16 Second vehicle wheel 18 Double arrow 20 double arrow 22 first electric machine 24 first rotor 26 first stator 28 housings 30 rotor element 32 rotor element 34 second electric machine 36 second rotor 38 second stator 40 rotor element 42 Rotor element DM two-engine operation K third clutch L1 first clutch L2 second clutch SM single-engine operation X fully closed position XS additional closing position QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] DE 10 2021 128 898 A1

[0002]

Claims

[1] Electric drive system (10) for a motor vehicle, comprising a first electric machine (22) having a first rotor (24), a second electric machine (34) having a second rotor (36) arranged coaxially to the first rotor (24), a first vehicle wheel (14) which can be driven by means of the first rotor (24), a second vehicle wheel (16) which can be driven by means of the second rotor (36), and a first clutch (L1) which is designed to couple the second rotor (36) to the first vehicle wheel (14) in a torque-transmitting manner, characterized by : - a second clutch (L2) which is designed to couple the second rotor (36) to the second vehicle wheel (16) in a torque-transmitting manner; and - a third clutch (K) which is designed to couple the first rotor (24) to the first vehicle wheel (14) in a torque-transmitting manner. [2] Electric drive system (10) according to claim 1, characterized by that the vehicle wheels (14, 16) are arranged at least substantially coaxially to the rotors (24, 36). [3] Electric drive system (10) according to claim 1 or 2, characterized by in that in the axial direction of the electric drive system (10) the first rotor (24), the third clutch (K), the first clutch (L1) and the second rotor (36) are arranged successively in the following order: the first rotor (24) - the third clutch (K) - the first clutch (L1) - the second rotor (36). [4] Electric drive system (10) according to one of the preceding claims, characterized by that the second clutch (L2) is arranged axially overlapping the first clutch (L1). [5] Electric drive system (10) according to one of claims 1 to 3, characterized bythat in the axial direction of the drive system (10) the second clutch (L2) is arranged between the first clutch (L1) and the second rotor (36). [6] Electric drive system (10) according to one of the preceding claims, characterized by that the first clutch (L1) and the second clutch (L2) are each designed as a multi-plate clutch. [7] Electric drive system (10) according to one of the preceding claims, characterized by that the third clutch (K) is designed as a claw clutch. [8] Method for operating an electric drive system (10) according to one of the preceding claims. [9] Method according to claim 8, characterized by that for a single-motor operation of the drive system (10), the first clutch (L1) and the second clutch (L2) are each operated in a closed position. [10] Method according to claim 8 or 9, characterized bythat for a two-engine operation of the drive system (10), the third clutch (K) and the second clutch (L2) are each operated in a closed position.

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