Method for operating a multi-clutch transmission, and corresponding multi-clutch transmission

Abstract

The invention relates to a method for operating a multi-clutch transmission (4) for a motor vehicle (1). The multi-clutch transmission (4) has a transmission input shaft (7), which is coupled or can be coupled to a drive device (2) of the motor vehicle (2), and a transmission output shaft (8), said input shaft and output shaft being drivingly coupled together at least temporarily via a first clutch (9) and a first sub-transmission (5) and at least temporarily via a second clutch (10) and a second sub-transmission (6). According to the invention, an electric machine (11) is at least temporarily drivingly coupled on the output side to the multi-clutch transmission (4) in order to provide a drive torque, wherein a first target clutch torque which differs from zero is at least temporarily set on the first clutch (9), and simultaneously a second target clutch torque which differs from zero is set on the second clutch (10).

Description

[0001] Method for operating a multiple clutch transmission and corresponding multiple clutch transmission

[0002] DESCRIPTION:

[0003] The invention relates to a method for operating a multi-clutch transmission for a motor vehicle, wherein the multi-clutch transmission has a transmission input shaft that is or can be coupled to a drive device of the motor vehicle, and a transmission output shaft that are drive-coupled to one another at least temporarily via a first clutch and a first sub-transmission, and at least temporarily via a second clutch and a second sub-transmission. The invention further relates to a corresponding motor vehicle.

[0004] For example, the prior art document DE 102 44 026 A1 is known. This document describes a method and a device for actively reducing clutch judder in a motor vehicle. In motor vehicles, vibrations occur in the drive train during the slip phase of a clutch, which are generated in the vehicle clutch. These vibrations arise when a slipping clutch generates periodic torques that lie within the natural frequency range of the drive train, which is dynamically separated by the clutch. Such torsional vibrations are converted into longitudinal vibrations in the drive train by the vehicle's drive wheels and are perceived as unpleasant by the vehicle occupants. A method and a device are presented with which these disruptive vibrations are reduced, at least in terms of their amplitude.For this purpose, the method provides for detecting the disturbing vibrations with the aid of a control and regulation device and suitable sensors and, if previously defined limit values ​​are exceeded, for activating at least one device which acts on components of the vehicle in such a way that the disturbing vibrations are dampened or compensated.

[0005] The object of the invention is to propose a method for operating a motor vehicle which has advantages over the prior art, in particular enabling the motor vehicle to be driven as flexibly and quietly as possible by means of an electric machine.

[0006] This is achieved according to the invention with a method for operating a motor vehicle having the features of claim 1. It is provided that an electric machine is coupled, from a drive-technical perspective, at least temporarily to provide a drive torque with the multiple-clutch transmission on the output side, wherein at least temporarily a first target clutch torque different from zero is set on the first shift clutch and at the same time a second target clutch torque different from zero is set on the second shift clutch.

[0007] Advantageous embodiments with useful further developments of the invention are specified in the dependent claims. It should be noted that the exemplary embodiments explained in the description are not limiting; rather, any variations of the features disclosed in the description, the claims, and the figures are feasible.

[0008] The multiple-clutch transmission is preferably a component of the motor vehicle. The motor vehicle has the drive device for driving the same. The drive device thus serves to provide a drive torque directed towards driving the motor vehicle. The drive torque is provided at least temporarily by a drive unit of the drive device, which is preferably in the form of an internal combustion engine. The multiple-clutch transmission is provided and designed to drive-couple the drive device or the drive unit of the drive device to at least one wheel axle of the motor vehicle. Thus, at least temporarily, the wheel axle is drive-coupled to the drive device or connected to it via the multiple-clutch transmission.

[0009] The multi-clutch transmission has the transmission input shaft, via which the multi-clutch transmission is coupled to the drive device. The drive device or the drive unit of the drive device is thus drive-coupled or can be coupled to the multi-clutch transmission on the input side, in particular permanently and / or via at least one starting clutch. On the output side, the multi-clutch transmission has the transmission output shaft. The transmission output shaft is coupled, or at least can be coupled, for example, to at least one wheel axle of the motor vehicle. The wheel axle of the motor vehicle preferably has several sub-axles, which are connected both to one another and to the transmission output shaft via an axle differential.At least one wheel of the motor vehicle is located on each of the partial axles, so that the wheels of the motor vehicle are drive-coupled to each other via the axle differential on the one hand and to the transmission output shaft on the other.

[0010] The multi-clutch transmission comprises the first sub-transmission and the second sub-transmission, via which the transmission input shaft is at least temporarily coupled to the transmission output shaft for drive purposes. For example, the transmission input shaft is at least temporarily connected to the transmission output shaft in a rotationally fixed manner via the first clutch and the first sub-transmission. By opening and closing the first clutch accordingly, the rotationally fixed connection between the transmission input shaft and the first sub-transmission can be interrupted or established. The same applies to the second clutch and the second sub-transmission.

[0011] The first sub-transmission and the second sub-transmission preferably have different gear ratios. Thus, a gear ratio between the transmission input shaft and the transmission output shaft can be switched or adjusted by correspondingly opening and closing the two clutches. The multi-clutch transmission is thus a dual-clutch transmission. Preferably, the first sub-transmission and the second sub-transmission are each designed as a manual transmission with multiple gears, in which at least one gear from the multiple gears can be selected and adjusted. The gears of the two sub-transmissions differ from one another in terms of their gear ratio.In this respect, the multi-clutch transmission has several gears, which are composed of the gears of the first sub-transmission and the gears of the second sub-transmission, each with different gear ratios. The two sub-transmissions are connected to the transmission output shaft on the output side in a rotationally fixed manner, particularly permanently.

[0012] The invention provides that, in addition to the drive device of the motor vehicle, an electric machine is present. This electric machine is intended and configured to provide, at least temporarily, the drive torque directed toward driving the motor vehicle, in particular without assistance from the drive device. The drive torque is thus provided temporarily by the drive device, temporarily by the electric machine, and temporarily by the drive device and the electric machine jointly. The motor vehicle is, in particular, a hybrid vehicle.

[0013] To provide the drive torque, the electric machine is at least temporarily coupled, from a drive-technical perspective, on the output side to the multi-clutch transmission. This means that the electric machine is coupled to the multi-clutch transmission in such a way that a drive torque can be or is provided to the transmission output shaft by means of the electric machine even when the first clutch and the second clutch are fully disengaged. For this purpose, the electric machine is preferably rigidly coupled, or at least temporarily rigidly coupled, to the transmission output shaft even when the first clutch and the second clutch are fully disengaged.

[0014] Particularly preferably, the electric machine can be coupled to the transmission output shaft, in particular by means of a separating clutch. This means that the electric machine is drive-connected to the transmission output shaft via the separating clutch, in particular directly. When the separating clutch is engaged, the electric machine is coupled to the transmission output shaft, preferably rigidly; when the separating clutch is disengaged, however, it is decoupled from it, preferably completely. The drive device is thus coupled or can be coupled on the input side to the transmission input shaft of the multiple-clutch transmission, while the electric machine is coupled or can be coupled on the output side to the transmission output shaft of the multiple-clutch transmission. In other words, the drive device is drive-connected to the transmission output shaft only indirectly via the multiple-clutch transmission.The electric motor, on the other hand, is directly coupled to the transmission output shaft or at least can be coupled to it.

[0015] In principle, from a drive technology perspective, the electric motor can be provided at any location between the multi-clutch transmission and at least one wheel axle of the motor vehicle. For example, the electric motor can be integrated into the wheel axle of the motor vehicle and / or into a wheel hub of the wheel axle. However, the electric motor is particularly preferably a component of the multi-clutch transmission. For example, the electric motor is integrated into a housing of the multi-clutch transmission on a side opposite the transmission input shaft and / or is attached to the housing.

[0016] It is now intended to use, at least temporarily, only the electric motor to drive the motor vehicle. Such a state occurs, for example, in purely electric driving operation of the motor vehicle designed as a hybrid vehicle. In this case, the electric motor coupled to the output side of the multi-clutch transmission is operated to provide the drive torque. Preferably, the drive unit is stationary, switched off, or idling. A standstill of the drive unit is to be understood in particular as meaning that a drive shaft of the drive unit, for example a crankshaft of the drive unit designed as an internal combustion engine, has a speed of zero.However, it can also be provided that the drive unit is, for example, in idle mode, whereby the drive shaft has a speed other than zero but does not contribute anything to the drive torque.

[0017] During such operation, it could be provided to fully disengage both the first clutch and the second clutch, whereby the transmission input shaft and the transmission output shaft would be completely separated from each other in terms of drive technology, and consequently the drive mechanism would also be completely separated from the two sub-transmissions. However, during operation of the electric motor coupled to the multi-clutch drive on the output side, the speed of the transmission output shaft is at least temporarily different from zero.

[0018] Due to the complete separation of the two sub-gearboxes from the transmission input shaft on the input side and their rotationally fixed coupling to the transmission output shaft on the output side, acoustic noises can occur at non-zero transmission output shaft speeds due to manufacturing-related mechanical play in the two sub-gearboxes, which can be perceived as disturbing by the driver of the vehicle. In particular, backlash occurring between the teeth of the gears of the two sub-gearboxes during load changes of the electric motor leads to acoustic noises that can be perceived as disturbing.

[0019] The invention now provides for the first target clutch torque to be set, at least temporarily, on the first clutch and the second target clutch torque to be set, at the same time, on the second clutch. The first target clutch torque and the second target clutch torque are different from zero, in particular greater than zero. This means that the first clutch and the second clutch are set to transmit a maximum torque corresponding to the first target clutch torque and the second target clutch torque, respectively. The target clutch torque is therefore understood to be the maximum torque that can be transmitted via the respective clutch.

[0020] The first clutch and the second clutch are designed, for example, as a hydraulically or mechanically actuated clutch, in particular as a multi-plate clutch. Accordingly, each of the two clutches has an actuating element by means of which a contact pressure is applied to the clutch. The contact pressure is determined based on the target clutch torque, and this contact pressure is adjusted at the respective clutch. Consequently, slippage occurs at the two clutches if the drive torque provided by the output side, in particular the drive torque provided by the electric motor, is greater than the target clutch torque adjusted at the respective clutch.

[0021] In other words, the invention provides that at least temporarily, when the speed of the transmission output shaft is different from zero, a target clutch torque different from zero is set on the first shifting clutch and on the second shifting clutch, namely the first target clutch torque and the second target clutch torque. In this case, it can be provided that the first target clutch torque corresponds to the second target clutch torque, for example if the first shifting clutch and the second shifting clutch are identical. In this respect, at least temporarily, a target clutch torque different from zero is set on the first shifting clutch and simultaneously on the second shifting clutch. Thus, the two shifting clutches are not fully open, but are at least partially closed with slipping. This preferably takes place during purely electric driving operation of the motor vehicle.

[0022] The procedure described above results in both the first sub-transmission and the second sub-transmission being connected to the transmission input shaft via the respective clutch during purely electric driving operation, at least in a slipping manner. By setting the first target clutch torque (not zero) and the second target clutch torque (not zero) on the two clutches, a mechanical tensioning of the two sub-transmissions occurs, thereby reducing or preventing the acoustic noises described above. The invention thus enables particularly quiet driving operation using the electric motor coupled to the multi-clutch transmission on the output side.

[0023] A further development of the invention provides that the first target clutch torque and / or the second target clutch torque are each selected to be greater than a slip point torque corresponding to a slip point of the respective clutch. The slip point or kiss point or engagement point of the clutch is to be understood in particular as a contact force at the presence of which at the respective clutch there is at least a minimal frictional connection between the transmission input shaft and the respective sub-transmission, so that at least the slip point torque can be transmitted via the respective clutch. For example, there is contact between the friction surfaces of the clutches designed as multi-plate clutches, so that at least the slip point torque can be transmitted via the multi-plate clutch at the greatest possible slip.The first target clutch torque and / or the second target clutch torque are now selected to be greater than the slip point torque. This ensures that at least the slip point torque can be reliably transmitted via the respective clutch. Since the slip point or the slip point torque at the respective clutch cannot usually be determined exactly, it can alternatively be provided that the slip point torque for each of the clutches is determined from a corresponding characteristic curve and / or determined as part of a test series. In this case, the respective target clutch torque is selected to be equal to the determined and / or determined slip point torque. In practice, a slip point torque of approximately 2 Nm to 8 Nm, for example, has proven effective, depending on the clutch design and component tolerance.If this value is selected as the target clutch torque, the procedure according to the invention can be carried out reliably with the lowest possible friction losses.

[0024] A further development of the invention provides that the first target clutch torque and / or the second target clutch torque are each selected to be smaller than a nominal clutch torque of the respective clutch. The nominal clutch torque is understood to be the maximum possible torque that can be reliably and slip-freely transmitted via the respective clutch during intended operation without causing permanent damage to the clutch.

[0025] Preferably, the first target clutch torque and / or the second target clutch torque correspond to at most 5%, at most 4%, at most 3%, at most 2%, or at most 1% of the nominal clutch torque. This allows the first target clutch torque and / or the second target clutch torque to be selected in a particularly simple manner based on a known nominal clutch torque of the respective clutch.

[0026] A further development of the invention provides that the first target clutch torque and the second target clutch torque are adjusted on the clutches during a load change. A load change is understood to mean, in particular, an acceleration or deceleration of the motor vehicle, in particular a starting process of the motor vehicle from a standstill. During such a load change, a corresponding acceleration or deceleration of the speed of the transmission output shaft occurs, which leads to undesirable acoustic noises due to the mechanical play of the two sub-transmissions explained above.

[0027] It is now planned to set the first target clutch torque and the second target clutch torque on the clutches. This is done, for example, based on a speed gradient of the transmission output shaft. This reduces or eliminates the undesirable acoustic noise caused by load changes.

[0028] A further development of the invention provides that, before and / or after the load change is performed, a third target clutch torque equal to zero is set at the clutches, at least temporarily. In this respect, the third target clutch torque is provided in addition to the first target clutch torque and the second target clutch torque. This third target clutch torque is set at the clutches, in particular, by fully disengaging them.

[0029] In this respect, the two clutches are initially fully open, at least temporarily, before the load change is implemented. During the load change, in particular immediately at the beginning of the load change, the first target clutch torque and the second target clutch torque are set on the clutches. This is done, for example, by means of a control unit that detects an impending load change, for example, based on the driver pressing an accelerator pedal and / or a brake pedal. Additionally and / or alternatively, the impending load change can be detected by a driver assistance system.

[0030] After the load change has been completed, particularly immediately after the end of the load change, the third target clutch torque is at least temporarily reset on the clutches. This is preferably also done by means of the control unit, which is appropriately provided and configured to detect the end of the load change. This procedure minimizes the friction losses occurring at the clutches.

[0031] A further development of the invention provides that the load change is a load change of the electric motor. The load change is, in particular, a load change of the electric motor during purely electric operation of the motor vehicle. The electric motor is preferably controlled by power electronics. A load change of the electric motor is therefore associated with a corresponding control of the power electronics.

[0032] It is now planned to adjust the first target clutch torque and the second target clutch torque on the clutches when the electric motor's load changes. This prevents and reduces the acoustic noises described above, which occur due to a change in the transmission output shaft speed caused by the electric motor's load change. This enables particularly quiet, all-electric operation of the vehicle.

[0033] A further development of the invention provides that the electric machine is coupled to the transmission output shaft via a spur gear and / or by means of a separating clutch. As already explained above, the electric machine is coupled to the multiple clutch transmission on the output side. The spur gear has at least one spur gear stage and enables a particularly space-saving arrangement of the electric machine on the multiple clutch transmission. In this case, for example, an axis of rotation of the electric machine, in particular an axis of rotation of a stator of the electric machine, is arranged parallel to a rotational axis of the transmission output shaft. The separating clutch is present additionally and / or alternatively. The separating clutch is preferably designed as a claw clutch and enables a drive-related separation of the electric machine from the multiple clutch transmission.Particularly preferably, the separating clutch is arranged coaxially with the transmission output shaft. The electric motor, or the rotational axis of the electric motor's stator, is also arranged coaxially, for example, or alternatively, by means of the spur gear, parallel to the transmission output shaft. This enables a compact and space-saving arrangement of the electric motor. At the same time, it is possible to operate the motor vehicle without using the electric motor.

[0034] A further development of the invention provides that the transmission output shaft and / or the electric machine are at least temporarily coupled to a first wheel axle and / or a second wheel axle of the motor vehicle. Reference has already been made to the at least one wheel axle of the motor vehicle. The at least one wheel axle is preferably the first wheel axle. This is preferably permanently coupled to the transmission output shaft and is present, for example, as a front axle of the motor vehicle. In addition to the first wheel axle, there is a second wheel axle, for example, as a rear axle of the motor vehicle. In principle, however, the first wheel axle can also be the rear axle and the second wheel axle can be the front axle of the motor vehicle.

[0035] The motor vehicle therefore has at least two wheel axles, the first wheel axle being permanently coupled to the transmission output shaft. The second wheel axle can also be permanently coupled to the transmission output shaft. However, the second wheel axle is preferably coupled to the transmission output shaft by means of a third clutch. The third clutch can be used to decouple the second wheel axle from the transmission output shaft in terms of drive technology. The third clutch is preferably a component of the multiple-clutch transmission and is designed as a multi-plate clutch. In terms of drive technology, the third clutch is preferably integrated into the multiple-clutch transmission between the two sub-transmissions and the electric motor coupled to the multiple-clutch transmission on the output side.This allows both the second wheel axle and the electric motor to be separated from the transmission output shaft using the third clutch. This creates a particularly flexible multi-clutch transmission.

[0036] A further development of the invention provides that the first target clutch torque and the second target clutch torque are set on the clutches when a speed of the transmission output shaft lies within a speed range limited by a first speed limit and a second speed limit. Due to other acoustic noise sources, such as wind noise and rolling noise from the motor vehicle's wheels, the volume of which depends on the current driving speed of the motor vehicle, the above-described acoustic noises caused by the mechanical play of the sub-transmissions are only perceived as disturbing when they lie within the speed range.

[0037] The first speed limit preferably corresponds to a minimum driving speed of the motor vehicle that the vehicle must have reached before the method according to the invention is applied. Particularly preferably, the first speed limit corresponds to a driving speed of zero, so that the method according to the invention is already implemented during a starting process using the electric motor. During such a starting process, the acoustic noises are perceived as particularly disturbing.

[0038] The second speed limit preferably corresponds to a maximum speed of the motor vehicle, beyond which the method according to the invention is no longer carried out. The maximum speed preferably corresponds to a driving speed at which, when reached or exceeded, the drive torque provided for driving the motor vehicle is no longer provided by the electric motor or only jointly by the electric motor and the drive device. This ensures that the method is only carried out within a driving speed range in which purely electric propulsion of the motor vehicle with the electric motor is provided.

[0039] The invention further relates to a multiple clutch transmission for a motor vehicle, in particular for carrying out the method according to the explanations in the context of this description, wherein the multiple clutch transmission has a transmission input shaft which is coupled or can be coupled to a drive device of the motor vehicle and a transmission output shaft which are drive-technically coupled to one another at least temporarily via a first shift clutch and a first partial transmission and at least temporarily via a second shift transmission and a second partial transmission.It is provided that an electric machine is coupled, in terms of drive technology, at least temporarily to the output side of the multiple clutch transmission in order to provide a drive torque, wherein the multiple clutch transmission is provided and designed to set, at least temporarily, a first target clutch torque different from zero at the first shifting clutch and, at the same time, a second target clutch torque different from zero at the second shifting clutch.

[0040] The invention further relates to a motor vehicle with a multiple clutch transmission, in particular a multiple clutch transmission according to the embodiments within the scope of this description.

[0041] The advantages of such a design of the multi-clutch transmission and the motor vehicle, as well as a corresponding procedure, have already been pointed out. Both the multi-clutch transmission and the motor vehicle, as well as the method for operating them, can be further developed according to the explanations in this description, so reference is made to these in this regard.

[0042] The features and feature combinations described in the description, in particular the features and feature combinations described in the following description of the figures and / or shown in the figures, can be used not only in the respective combination specified, but also in other combinations or on their own, without departing from the scope of the invention. Thus, embodiments are also considered to be encompassed by the invention that are not explicitly shown or explained in the description and / or the figures, but which emerge from the explained embodiments through combinations of features or can be derived from them.

[0043] The invention will be explained in more detail below with reference to the exemplary embodiments shown in the drawings, without limiting the invention.

[0044] Figure 1 is a schematic representation of a motor vehicle with a drive device.

[0045] Figure 1 shows a schematic representation of a motor vehicle 1 with a drive device 2. The drive device 2 has a drive unit 3 and a multi-clutch transmission 4. The multi-clutch transmission 4 has a first sub-transmission 5 and a second sub-transmission 6. A transmission input shaft 7 and a transmission output shaft 8 are coupled to one another at least temporarily via a first shift clutch 9 and the first sub-transmission 5, and at least temporarily via a second shift clutch 10 and the second sub-transmission 6. The two sub-transmissions 5 and 6 are rotationally fixedly coupled to the transmission output shaft 8. The multi-clutch transmission 4 is therefore a dual-clutch transmission.

[0046] An electric motor 11 is drive-coupled on the output side to the transmission output shaft 8. The transmission output shaft 8 is connected via a first output shaft 12 to a first wheel axle 13 and via a second output shaft 14 to a second wheel axle 15 of the motor vehicle 1. The first wheel axle 13 has a first sub-axle 16 and a second sub-axle 17, which are drive-coupled to one another via a first axle differential 18 and to the first output shaft 12. Accordingly, the second wheel axle 15 has a first sub-axle 19, a second sub-axle 20, and a second axle differential 21.

[0047] The electric machine 11 is coupled to a separating clutch 23 via a spur gear 22. The separating clutch 23 is arranged coaxially to a rotational axis of the transmission output shaft 8. The separating clutch 23 serves to separate the electric machine 11 from the transmission output shaft 8 and is designed, for example, as a dog clutch. The second output shaft 14 is drive-coupled to the transmission output shaft 8 via a third clutch 24. The third clutch 24 is designed, for example, as a multi-plate clutch and serves to separate the second output shaft 14 from the transmission output shaft 8. In terms of drive, a further separating clutch 25, which is designed, for example, as a dog clutch, is arranged between the second output shaft 14 and the second axle differential 21.By disengaging the third clutch 24 and the further separating clutch 25, the second wheel axle 15, the second output shaft 14, and the transmission output shaft 8 can be completely separated from each other in terms of drive. A further electric motor 26 is arranged on the drive unit 3 and serves to start the drive unit 3.

[0048] The transmission input shaft 7 and a crankshaft of the drive unit 3 share a common axis of rotation 27. Thus, the axes of rotation of the transmission input shaft 27 and the crankshaft are arranged coaxially to one another. The transmission output shaft 8 and the second output shaft 14 share a common axis of rotation 28. Thus, the axes of rotation of the transmission output shaft 8 and the second output shaft 14 are arranged coaxially to one another and offset parallel to the axis of rotation 27 of the transmission input shaft 7 and the crankshaft. A rotation axis 29 of the electric machine 11 is arranged offset parallel to the axes of rotation 27 and 28.

[0049] The electric machine 11 is operated, at least temporarily, with the drive unit 3 switched off to drive the motor vehicle 1. A target clutch torque different from zero is set, at least temporarily, on the first clutch 9 and simultaneously on the second clutch 10. As a result, the two sub-transmissions 5 and 6 are mechanically preloaded during purely electric driving of the motor vehicle 1, thereby reducing acoustically perceptible noises, which are caused in particular by backlash between the teeth of the two sub-transmissions 5 and 6.

[0050] LIST OF REFERENCE SYMBOLS:

[0051] 1 motor vehicle

[0052] 2 drive device

[0053] 3 Drive unit

[0054] 4 multi-clutch transmissions

[0055] 5 first partial transmission

[0056] 6 second partial transmission

[0057] 7 Gearbox input shaft

[0058] 8 Gearbox output shaft

[0059] 9 first clutch

[0060] 10 second clutch

[0061] 11 electric machine

[0062] 12 first output shaft

[0063] 13 first wheel axle

[0064] 14 two output shafts

[0065] 15 second wheel axle

[0066] 16 first sub-axis

[0067] 17 second sub-axis

[0068] 18 first axle differential

[0069] 19 first sub-axis

[0070] 20 second sub-axis

[0071] 21 second axle differential

[0072] 22 spur gears

[0073] 23 Separating clutch

[0074] 24 third clutch

[0075] 25 additional separating couplings

[0076] 26 additional electric machines

[0077] 27 axis of rotation

[0078] 28 axis of rotation

[0079] 29 axis of rotation

Claims

PATENT CLAIMS:

1. A method for operating a multiple-clutch transmission (4) for a motor vehicle (1), wherein the multiple-clutch transmission (4) has a transmission input shaft (7) which is or can be coupled to a drive device (2) of the motor vehicle (1), and a transmission output shaft (8), which are at least temporarily coupled to one another in terms of drive technology via a first shifting clutch (9) and a first partial transmission (5) and at least temporarily via a second shifting clutch (10) and a second partial transmission (6), characterized in that an electric machine (11) is at least temporarily coupled to the multiple-clutch transmission (4) on the output side in terms of drive technology to provide a drive torque, wherein at least temporarily a first target clutch torque different from zero is set at the first shifting clutch (9) and at the same time a second target clutch torque different from zero is set at the second shifting clutch (10).

2. Method according to claim 1, characterized in that the first target clutch torque and / or the second target clutch torque are each selected to be greater than a slip point torque corresponding to a slip point of the respective clutch (9, 10).

3. Method according to one of the preceding claims, characterized in that the first target clutch torque and / or the second target clutch torque are each selected to be smaller than a nominal clutch torque of the respective clutch (9, 10).

4. Method according to one of the preceding claims, characterized in that the first target clutch torque and the second target clutch torque are set during a load change on the clutches (9, 10).

5. Method according to one of the preceding claims, characterized in that before carrying out the load change and / or after carrying out the load change on the clutches (9, 10), a third target clutch torque is set at least temporarily, which is equal to zero.

6. Method according to one of the preceding claims, characterized in that the load change is a load change of the electrical machine (11).

7. Method according to one of the preceding claims, characterized in that the electric machine (11) is coupled to the transmission output shaft (8) via a spur gear (22) and / or by means of a separating clutch (23).

8. Method according to one of the preceding claims, characterized in that the transmission output shaft (8) and / or the electric machine (1) are coupled at least temporarily to a first wheel axle (13) and / or a second wheel axle (15) of the motor vehicle (1).

9. Method according to one of the preceding claims, characterized in that the first target clutch torque and the second target clutch torque are set at the clutches (9, 10) when a speed of the transmission output shaft (8) is within a speed range limited by a first speed limit value and a second speed limit value.

10. Multiple clutch transmission (4) for a motor vehicle (1), in particular for carrying out the method according to one or more of the preceding claims, wherein the multiple clutch transmission (4) has a transmission input shaft (7) which is or can be coupled to a drive device (2) of the motor vehicle (1) and a transmission output shaft (8), which are drive-technically coupled to one another at least temporarily via a first clutch (9) and a first partial transmission (5) and at least temporarily via a second clutch (10) and a second partial transmission (6), characterized in that an electric machine (11) at least temporarily coupled to the multiple clutch transmission (4) on the output side in terms of drive technology to provide a drive torque, wherein the multiple clutch transmission (2) is provided and designed to at least temporarily set a first target clutch torque different from zero on the first shift clutch (9) and at the same time set a second target clutch torque different from zero on the second shift clutch (10).

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