DE102021205944B4 - Transmission for a motor vehicle and motor vehicle drive train and method for operating the transmission - Google Patents

Abstract

Transmission (4; 4'; 4") for a motor vehicle, comprising a drive shaft (9) which is set up to connect the transmission (4; 4'; 4") to a drive engine of the motor vehicle, a first input shaft (10 ), which is coupled to a rotor (12) of a first electric machine (13), and an output shaft (29), which is coupled to an output side (39), wherein the first input shaft (10) on the one hand by closing a first switching element ( A) can be connected to the output shaft (29) via a first spur gear stage (30) and on the other hand by actuating a second switching element (B) via a second spur gear stage (34), with a planetary stage (40; 40') having a first element (41; 41'), a second element (42; 42') and a third element (43; 43') in the form of a sun gear (44; 44'), a planet carrier (45; 45') and a ring gear (46 ; 46') is provided, wherein the third element (43; 43') of the planetary stage (40; 40') is non-rotatably connected to the drive shaft (9), and wherein a third shifting element (C), a fourth shifting element (D) and a fifth switching element (G) are provided, wherein the drive shaft (9) can be fixed via the fifth switching element (G), characterized in that the first element (41; 41') of the planetary stage (40; 40') is connected in a rotationally fixed manner to a second input shaft (11) which is coupled to a rotor (24) of a second electric machine (23), whereas the second element (42; 42') of the Planetary stage (40; 40') can be coupled to the output shaft (29) on the one hand by closing the third switching element (C) via the second spur gear stage (34) and on the other hand by actuating the fourth switching element (D) via the first spur gear stage (30). is.

Description

The invention relates to a transmission for a motor vehicle, comprising a drive shaft that is designed to connect the transmission to a drive engine of the motor vehicle, a first input shaft that is coupled to a rotor of a first electric machine, and an output shaft that is connected to an output side is coupled, wherein the first input shaft can be connected to the output shaft on the one hand by closing a first switching element via a first spur gear stage and on the other hand by actuating a second switching element via a second spur gear stage. Furthermore, the invention relates to a motor vehicle drive train and a method for operating a transmission.

Multi-gear transmissions are known in motor vehicles, in which several different transmission ratios can be shifted as gears by actuating corresponding shifting elements, this preferably being carried out automatically. In this case, the transmission is used to suitably implement a tractive force available from a drive machine of the motor vehicle with regard to various criteria. In transmissions for hybrid vehicles, an aforementioned transmission is often combined with one or more electric machines, with the at least one electric machine being able to be integrated in different ways in the transmission to represent different operating modes, such as purely electric driving.

From the FR 2 811 395 A1 discloses a transmission in which a drive shaft and an input shaft are arranged coaxially to one another and can be connected to one another in a torque-proof manner via a switching element. The drive shaft designed here as a solid shaft can be connected via a separating clutch to an upstream drive machine in the form of an internal combustion engine, whereas a rotor of an electric machine is connected to the input shaft. Both the input shaft and the drive shaft can each be connected via spur gear stages by actuation of an associated switching element to an output shaft that is parallel to the axis and is coupled to an output side of the transmission.

Also reveal DE 10 2020 203 779 A1 , DE 10 2020 203 789 A1 , DE 10 2016 225 236 A1 , DE 11 2008 001 553 T5 , DE 199 03 936 A1 and DE 10 2011 005 562 A1 gears for motor vehicles.

Proceeding from the state of the art described above, it is now the object of the present invention to realize a transmission that is as compact as possible with low production costs, it being possible to realize hybrid functions via the transmission.

This object is achieved based on the preamble of claim 1 in conjunction with its characterizing features. The dependent claims that follow each specify advantageous developments of the invention. A motor vehicle drive train, in which an aforementioned transmission is provided, is also the subject of claim 15. In addition, claims 16 and 17 each relate to a method for operating a transmission.

According to the invention, a transmission includes a drive shaft that is designed to connect the transmission to a drive engine of the motor vehicle, a first input shaft that is coupled to a rotor of a first electric machine, and an output shaft that is coupled to an output side. The first input shaft can be connected to the output shaft on the one hand by closing a first shifting element via a first spur gear stage and on the other hand by actuating a second shifting element via a second spur gear stage.

In the context of the invention, a “shaft” is to be understood as meaning a rotatable component of the transmission, via which a power flow can be guided between components, if necessary with simultaneous actuation of a corresponding shifting element. The respective shaft can connect components to one another axially or radially or both axially and radially. The respective shaft can also be present as an intermediate piece, via which a respective component is connected radially, for example.

In the context of the invention, “axial” means an orientation in the direction of a longitudinal central axis of the transmission, parallel to which the axes of rotation of the shafts of the transmission are also aligned. “Radial” is then to be understood as meaning an orientation in the diameter direction of a respective component.

According to the invention, the first input shaft can be coupled to the output shaft via the first spur gear stage, for which purpose the first switching element has to be switched to a closed state. On the other hand, the first input shaft can also be brought into connection with the output shaft via the second spur gear stage by closing the second shifting element, so that in this case a power flow guidance takes place from the first input shaft via the second spur gear stage to the output shaft.

Within the scope of the invention, a spur gear stage is made up of at least two meshing spur gears in a manner known in principle to those skilled in the art, via which shafts that are offset relative to one another are coupled or can be coupled. The individual spur gear can be placed as a fixed gear in a rotationally fixed manner on the respective associated shaft, so that a rotary movement of the shaft also results in a corresponding rotary movement of the associated spur gear and vice versa. However, the individual spur gear can also be rotatably mounted as a loose wheel on the respective associated shaft and is then possibly only fixed on the shaft by actuating an associated switching element, which then results in the non-rotatable connection between the spur gear and the associated shaft. Spur gears of the transmission according to the invention are preferably designed as helical gears.

The invention now includes the technical teaching that a planetary stage is provided with a first element, a second element and a third element in the form of a sun gear, a planet carrier and a ring gear. The third element of the planetary stage is non-rotatably connected to the drive shaft, while the first element of the planetary stage is non-rotatably connected to a second input shaft, which is coupled to a rotor of a second electric machine. Furthermore, the second element of the planetary stage can be coupled to the output shaft on the one hand by engaging a third shifting element via the second spur gear stage and on the other hand by actuating a fourth shifting element via the first spur gear stage. Furthermore, the drive shaft can be fixed via a fifth switching element.

In other words, in addition to the first spur gear stage and the second spur gear stage, the transmission according to the invention also has a planetary stage which is composed of a first element, a second element and a third element. Of these elements, one element is a sun gear, one element is a planetary carrier and one element is a ring gear. In addition, the third element is constantly non-rotatably connected to the drive shaft, while the first element of the planetary stage is permanently non-rotatably connected to a second input shaft. A rotor of a second electric machine is connected to this second input shaft. The second element of the planetary stage can then be coupled to the output shaft via the second spur gear stage, for which purpose a third switching element must be actuated. As an alternative to this, there is also the possibility of closing a fourth shifting element and thereby coupling the second element of the planetary stage to the output shaft via the first spur gear stage. In addition, a fifth switching element is also provided, when it is actuated, the drive shaft is fixed and subsequently prevented from rotating.

The configuration of a transmission according to the invention has the advantage that overall a compact transmission can be realized, which is also characterized by low manufacturing costs. Due to the integration of the two electric machines and also the upstream drive machine, a large number of different operating modes and thus a high level of functionality can also be implemented.

The transmission according to the invention has two electric machines, which makes the transmission suitable for use in a hybrid or electric vehicle. In this case, a rotor of the first electric machine is then directly or indirectly connected to the first input shaft, while the rotor of the second electric machine is coupled to the second input shaft, and this can also be accomplished by a direct or indirect connection. Within the scope of the invention, the individual electric machine can preferably be operated on the one hand as a generator and on the other hand as an electric motor. A "coupling" of the rotor of the respective electric machine with the associated input shaft is to be understood within the meaning of the invention as a connection between them, so that there is a constant speed dependency between the rotor of the respective electric machine and the associated input shaft. Precisely two electric machines are particularly preferably provided in the transmission according to the invention.

The drive shaft and the two input shafts are preferably coaxial with one another, with the drive shaft being designed in particular as a solid shaft, while the first input shaft is arranged as a hollow shaft, preferably axially overlapping the drive shaft and radially surrounding it. The second input shaft can also be in the form of a hollow shaft, which is placed radially surrounding the drive shaft. As an alternative to this, however, it is also conceivable that the second input shaft is also designed as a solid shaft, which is arranged on the front side of an axial end of the coaxial drive shaft. The planetary stage is more preferably also arranged coaxially to the drive shaft and the two input shafts, while the output shaft, with which both the first input shaft and the second element of the tarpaulin tenstufe on the one hand on the first spur gear and on the other on the second spur gear can be coupled, in particular is off-axis to the drive shaft, the input shafts and the planetary stage.

In the present case, the first shifting element, the second shifting element, the third shifting element and the fourth shifting element are clutches which, when actuated, connect the components of the transmission directly connected thereto in a rotationally fixed manner, possibly with a prior reduction of speed differences. In contrast, the fifth switching element is implemented as a brake, which fixes the component directly connected to it in the closed state and consequently prevents it from rotating. The fixing preferably takes place by means of a non-rotatable connection with a permanently stationary component of the transmission, which is preferably the transmission housing, a part of the transmission housing or a component connected thereto in a non-rotatable manner.

Different operating modes and also hybrid functions can be realized with the transmission according to the invention. Thus, the transmission according to the invention can be operated, inter alia, in such a way that a charging operation or a starting operation is implemented, for which purpose the third shifting element or the fourth shifting element is closed. Because when the third shifting element is engaged and the fourth shifting element is engaged, the output shaft and thus also the output side are coupled to the second element of the planetary stage via the second spur gear stage or the first spur gear stage, while the second input shaft and thus the second electric machine are connected to the first Element and the prime mover is connected to the third element of the planetary stage. In the generator mode of the electric machine, the charging mode can thereby be implemented, whereby this is possible particularly advantageously when the motor vehicle is stationary, since in this case the second element of the planetary stage is prevented from rotating via the output side and the stationary mass of the motor vehicle connected to it. In an electric motor operation of the electric machine, however, the upstream drive machine, which is designed in particular as an internal combustion engine, can also be started as a result.

As a further operating mode, a starting mode for forward travel when driven via the drive shaft and thus the upstream drive machine can also be implemented. For this purpose, either the third switching element or the fourth switching element is closed again, so that the drive motor drives via the third element of the planetary stage and at the same time supports the second electric machine on the first element of the planetary stage, while an output via the second element of the planetary stage and further, depending after the switching element has been actuated, either via the second spur gear stage or the first spur gear stage. Appropriate support of the torque via the second electric machine can be used to start off for forward travel.

In the transmission according to the invention, there is preferably a first gear between the first input shaft and the output shaft by closing the first shifting element, whereas a second gear between the first input shaft and the output shaft can be achieved by actuating the second shifting element. These two gears between the first input shaft and the output shaft can be used to integrate the first electric machine and thus be used for purely electric driving. Furthermore, a first gear between the second input shaft and the output shaft can be achieved by closing the fourth and fifth shifting element, while a second gear between the second input shaft and the output shaft can be realized by actuating the third and fifth shifting element. By fixing the drive shaft via the fifth switching element and thus also the third element of the planetary stage, the planetary stage can also be used to couple the second input shaft and thus also the second electric machine to the output side, with this coupling then being carried out either via the second spur gear stage or the first spur gear stage takes place, depending on whether the fourth switching element or the third switching element is additionally actuated. In this respect, purely electric driving can also be carried out using the second electric machine. One of the gears effective between the first input shaft and the output shaft can be shifted at the same time as one of the gears effective between the second input shaft and the output shaft. As a result, both electric machines can be driven together.

According to one embodiment of the invention, a sixth shifting element and a seventh shifting element are also provided, with the sixth shifting element locking the first element of the planetary stage when actuated, whereas actuation of the seventh shifting element connects two of the elements of the planetary stage in a rotationally fixed manner. The additional provision of these further switching elements has the advantage that the elements of the planetary stage can now also be coupled in such a way that the prime mover connected to the drive shaft in the installed state of the transmission is also connected to the Output side can be coupled. In this respect, driving via the upstream drive machine can also be implemented as a result.

Accordingly, the sixth switching element is a brake which, when actuated, fixes the first element of the planetary stage and subsequently prevents it from rotating. In the closed state, the seventh switching element ensures a non-rotatable connection between two of the elements of the planetary stage, so that it is blocked. In concrete terms, the seventh switching element can, when actuated, connect the first element and the second element or the first element and the third element or the second element and the third element of the planetary stage in a torque-proof manner.

In a further development of the aforementioned embodiment, a first gear results between the drive shaft and the output shaft by locking the fourth and sixth shifting element, while a second gear can be shifted between the drive shaft and the output shaft by actuating the fourth and seventh shifting element. In addition, a third gear between the drive shaft and the output shaft can be achieved by engaging the third and sixth shifting element, whereas a fourth gear between the drive shaft and the output shaft results by actuating the third and seventh shifting element.

According to one possible embodiment of the invention, the first spur gear comprises a first spur gear which is placed on a shaft in a rotationally fixed manner and meshes with a second spur gear of the first spur gear stage which is arranged in a rotationally fixed manner on the output shaft. The shaft can be connected in a rotationally fixed manner to the first input shaft via the first shifting element and to the second element of the planetary stage in a rotationally fixed manner by means of the fourth shifting element. In this way, a suitable ability to couple the first spur gear stage to both the first input shaft and the second element of the planetary stage can be realized.

Alternatively or additionally, the second spur gear includes a first spur gear, which meshes with a second spur gear of the second spur gear. This second spur gear is arranged on the output shaft in a rotationally fixed manner. The first spur gear of the second spur gear stage can then be connected in a rotationally fixed manner to the first input shaft via the second shifting element and to the second element of the planetary stage in a rotationally fixed manner by means of the third shifting element. The fact that the first spur gear of the second spur gear stage can be connected in a torque-proof manner to the first input shaft via the second shifting element on the one hand, and can also be connected in a torque-proof manner to the second element of the planetary stage by means of the third shifting element on the other hand, means that the second spur gear stage can also be first input shaft, as well as the second element of the planetary stage for a coupling with the output shaft. This dual use reduces the manufacturing effort.

It is one embodiment of the invention that the first element of the planetary stage is the sun gear, the second element of the planetary stage when the planetary stage is designed as a minus planetary gearset, the planetary carrier and when the planetary stage is designed as a plus planetary gearset, the ring gear, and the third element of the planetary stage when designed the planetary stage is the ring gear as a minus planetary set and the planetary carrier when the planetary stage is designed as a plus planetary set. If the planetary stage is realized as a negative planetary gear set, the first element of the planetary stage is the sun gear, the second element of the planetary stage is the planet carrier and the third element of the planetary stage is the ring gear. If, on the other hand, the planetary stage is a plus planetary set, the first element of the planetary stage is realized as a sun gear, the second element of the planetary stage as a ring gear and the third element of the planetary stage as a planetary carrier.

Alternatively, the first element of the planetary stage is the sun gear, the second element of the planetary stage when the planetary stage is designed as a minus planetary gear train is the ring gear and when the planetary stage is designed as a plus planetary gear train, it is the planet carrier, and the third element of the planetary stage when the planetary stage is designed as a minus planetary gear. Planetary set the planet carrier and if the planetary stage is designed as a plus planetary set, the ring gear. In contrast to the previous embodiment, the first element in the formation of the planetary stage as a minus planetary gear set is the sun gear, the second element is the ring gear and the third element is the planet carrier. If the planetary stage is implemented as a plus planetary gear set, the first element of the planetary stage is the sun gear, the second element of the planetary stage is the planet carrier and the third element of the planetary stage is the ring gear.

According to the invention, at least one, but preferably several, planetary gears are rotatably mounted in the planetary carrier in a negative planetary gear set, each of which meshes with the sun gear and the surrounding ring gear. In contrast, a planetary carrier in the case of the execution as a plus planetary gearset stores at least one pair of planetary gears, in which a planetary gear with the internal sun gear and the other planet gear is in mesh with the surrounding ring gear and the planet gears mesh with each other.

Where it is possible to connect the individual elements, a minus planetary gearset can be converted into a plus planetary gearset, in which case the ring gear and planetary carrier connection can then be swapped over compared to the negative planetary gearset design, and the standard gear ratio of the planetary stage can be increased by one is. Conversely, a plus planetary gear set could also be replaced by a minus planetary gear set, provided that the connection of the transmission elements allows this. In this case, in comparison to the plus planetary gear set, the ring gear and the planet carrier connection would also have to be swapped with one another, and a stationary gear ratio of the planetary stage would have to be reduced by one.

In a development of the invention, the individual shifting element is designed as a positive-locking shifting element, in particular as a claw shifting element. As an alternative to this, a positive-locking shifting element can also be a blocking synchronization. In principle, positive-locking switching elements have the advantage that they only have low drag torques when open and are accordingly characterized by a high level of efficiency. As an alternative to this, the individual shifting element could also be designed as a non-positive shifting element, for example as a multi-plate shifting element, in which case a non-positive shifting element can advantageously also be transferred to an actuated state under load.

According to one embodiment of the invention, the rotor of the first electric machine is arranged coaxially or off-axis with respect to the first input shaft. Alternatively or additionally, the rotor of the second electric machine is placed coaxially or off-axis to the second input shaft. The respective electric machine can therefore be arranged coaxially to the respective input shaft, with the respective rotor being either directly connected in a rotationally fixed manner to the associated input shaft or coupled to it via at least one intermediate transmission stage. The intermediate gear stage can be a spur gear stage and/or a planetary stage. If, on the other hand, the respective electric machine is provided with an offset axis relative to the respective input shaft, then the respective rotor is connected to the associated input shaft via at least one transmission stage or else a traction drive. In this case, too, the at least one transmission stage can be a spur gear stage and/or a planetary stage.

According to a variant of the invention, the first switching element and the second switching element are combined to form a switching device. This switching device particularly preferably has a common actuating device, via which the first switching element and the second switching element can be transferred from a neutral position into an actuated state. This enables the first switching element and the second switching element to be actuated via a common setting actuator, which correspondingly reduces the manufacturing effort.

Alternatively, but preferably in addition to the aforementioned variant, the third switching element and the fourth switching element are combined to form a switching device. This shifting device also has in particular an actuating device, via which the third shifting element on the one hand and the fourth shifting element on the other can be moved from a neutral position into a closed state. Thus, in this case too, a common setting actuator can be provided and the manufacturing effort can thus be reduced.

If the sixth switching element and the seventh switching element are provided, these are also combined to form a switching device in one variant of the invention. Preferably, either the sixth switching element or the seventh switching element can be transferred into an actuated state via a common actuating device from a neutral position and depending on the direction of movement. Thus, either the sixth shifting element or the seventh shifting element can be closed via a common setting actuator.

Within the scope of the invention, the transmission can be preceded by a starting element, for example a hydrodynamic torque converter or a friction clutch. This starting element can then also be part of the transmission and is used to design a starting process by enabling a slip speed between the internal combustion engine and the drive shaft of the transmission. However, the drive shaft is particularly preferably coupled to the upstream drive machine in an installed state of the transmission without an intermediate starting element, with a torsional vibration damper being able to be interposed, particularly when the drive machine is designed as an internal combustion engine. In addition, each shaft of the gearbox can in principle have a freewheel for the gearbox hause or be arranged to another wave.

The transmission according to the invention is in particular part of a motor vehicle drive train for a hybrid or electric vehicle and is then arranged between a drive motor of the motor vehicle designed as an internal combustion engine or as an electric machine and other components of the drive train following in the direction of power flow to the drive wheels of the motor vehicle. The drive shaft of the transmission is either permanently coupled in a rotationally fixed manner to a crankshaft of the internal combustion engine or can be connected to it via an intermediate separating clutch or a starting element, with a torsional vibration damper also being able to be provided between the internal combustion engine and transmission. Even in the case of an embodiment of the drive machine as an electric machine, a direct, non-rotatable connection of the drive shaft to a rotor of this electric machine can be completed. On the output side, the transmission within the motor vehicle drive train is then preferably coupled to a differential gear of a drive axle of the motor vehicle, although here there can also be a connection to a longitudinal differential, via which distribution to several driven axles of the motor vehicle takes place. The differential gear or the longitudinal differential can be arranged with the gear in a common housing. A torsional vibration damper can also be integrated into this housing.

The fact that two components of the transmission are "connected" or "coupled" in a rotationally fixed manner or "are connected to one another" means, within the meaning of the invention, that these components are permanently coupled so that they cannot rotate independently of one another. In this respect, no switching element is provided between these components, which can be elements of the planetary stage and/or spur gears of the spur gear stages and/or shafts and/or a transmission housing, but the corresponding components are rigidly coupled to one another.

If, on the other hand, a switching element is provided between two components, these components are not permanently coupled to one another in a rotationally fixed manner, but instead a rotationally fixed coupling is only carried out by actuating the switching element in between. An actuation of the switching element in the sense of the invention means that the relevant switching element is transferred to a closed state and as a result the components directly coupled thereto are adjusted in their rotational movements to one another. If the shifting element in question is designed as a positive shifting element, the components connected directly to one another in a rotationally fixed manner will run at the same speed, while in the case of a non-positive shifting element, there may be speed differences between the components even after it has been actuated. Within the scope of the invention, this desired or also undesired state is nevertheless referred to as a non-rotatable connection of the respective components via the switching element.

The invention is not limited to the specified combination of features of the main claim or the claims dependent thereon. There are also possibilities of combining individual features with one another, even if they emerge from the claims, the following description of preferred embodiments of the invention or directly from the drawings. Reference of the claims to the drawings by the use of reference signs is not intended to limit the scope of the claims.

• 1 eine schematische Ansicht eines Kraftfahrzeugantriebsstranges;
• 2 eine schematische Darstellung eines Teils des Kraftfahrzeugantriebsstranges aus 1 mit einem Getriebe entsprechend einer ersten Ausführungsform der Erfindung;
• 3 ein beispielhaftes Schaltschema des Getriebes aus 2,
• 4 eine tabellarische Darstellung unterschiedlicher Betriebsmodi des Kraftfahrzeugantriebsstranges gemäß 2;
• 5 eine schematische Ansicht eines Teils des Kraftfahrzeugantriebsstranges aus 1 mit einem Getriebe gemäß einer zweiten Ausgestaltungsmöglichkeit der Erfindung;
• 6 eine schematische Darstellung eines Teils des Kraftfahrzeugantriebsstranges aus 1 mit einem Getriebe gemäß einer dritten Ausführungsform der Erfindung;
• 7 ein beispielhaftes Schaltschema des Getriebes aus 5 oder 6; und
• 8 eine tabellarische Darstellung unterschiedlicher Betriebsmodi des Kraftfahrzeugantriebsstranges gemäß den 5 oder 6.

Advantageous embodiments of the invention, which are explained below, are shown in the drawings. It shows:

• 1 a schematic view of a motor vehicle drive train;
• 2 a schematic representation of a part of the motor vehicle drive train 1 with a transmission according to a first embodiment of the invention;
• 3 an example shift pattern of the transmission 2 ,
• 4 according to a tabular representation of different operating modes of the motor vehicle drive train 2 ;
• 5 Figure 12 is a schematic view of a portion of the automotive powertrain 1 with a transmission according to a second possible embodiment of the invention;
• 6 a schematic representation of a part of the motor vehicle drive train 1 with a transmission according to a third embodiment of the invention;
• 7 an example shift pattern of the transmission 5 or 6 ; and
• 8th a tabular representation of different operating modes of the motor vehicle drive train according to the 5 or 6 .

1 shows a schematic view of a motor vehicle drive train 1 of a hybrid vehicle vehicle, an internal combustion engine 2 being connected to a transmission 4 via an intermediate torsional vibration damper 3 in the motor vehicle drive train. A differential gear 5 is connected downstream of the gear 4 on the output side, via which a drive power is distributed to drive wheels 6 and 7 of a drive axle of the motor vehicle. The gear 4 and the torsional vibration damper 3 are combined in a common gear housing 8 of the gear 4, in which the differential gear 5 can then also be integrated. As also in 1 can be seen, the internal combustion engine 2, the torsional vibration damper 3, the gear 4 and also the differential gear 5 are aligned transversely to a direction of travel of the motor vehicle.

Out of 2 1 is a schematic representation of part of the motor vehicle drive train 1 1 in the area of the transmission 4, the latter being designed in accordance with a first embodiment of the invention. The transmission 4 includes a drive shaft 9, a first input shaft 10 and a second input shaft 11, which are arranged coaxially to one another. The drive shaft 9 is connected in a rotationally fixed manner to the torsional vibration damper 3 and is designed as a solid shaft which extends almost over the entire axial length of the transmission 4 . The first input shaft 10 is in the form of a hollow shaft, which is provided so as to overlap axially with the drive shaft 9 and surround it radially, while the second input shaft 11 is also designed as a solid shaft. The second input shaft 11 is placed on the end face of the drive shaft 9 and axially on a side of the drive shaft 9 that faces away from the connection to the torsional vibration damper 3 .

The first input shaft 10 is presently coupled to a rotor 12 of a first electric machine 13, this electric machine 13 being placed off-axis to the first input shaft 10 and having a stator 14 next to the rotor 12, which is permanently fixed to the transmission housing 8. The first electric machine 13 can be operated on the one hand as an electric motor and on the other hand as a generator. A coupling between the rotor 12 and the first input shaft 10 is completed via two spur gears 15 and 16, which are each composed of two spur gears 17 and 18 and 19 and 20. The spur gear 17 of the spur gear stage 15 is arranged in a rotationally fixed manner on a rotor shaft 21, via which the spur gear 17 is connected in a rotationally fixed manner to the rotor 12. The spur gear 17 meshes with the spur gear 18 which is arranged in a rotationally fixed manner on a shaft 22 which also carries the spur gear 19 of the spur gear stage 16 in a rotationally fixed manner. The spur gear 19 of the spur gear stage 16 then meshes with the spur gear 20 which is arranged on the first input shaft 10 in a rotationally fixed manner.

In addition to the electric machine 13, a second electric machine 23 is also provided, which is composed of a rotor 24 and a stator 25 and can also be operated on the one hand as an electric motor and on the other hand as a generator. The stator 25 of the second electric machine 23 is here also fixed to the transmission housing 8, while the rotor 24 is constantly non-rotatably connected to the second input shaft 11. Here, the second electric machine 23 is arranged coaxially to the second input shaft 11 and thus also to the first input shaft 10 and the drive shaft 9 .

A control device 26 is also assigned to the two electric machines 13 and 23 , via which operation of the individual electric machine 13 or 23 can be regulated and which is also connected to an electric energy store 27 . The control device 26 can be used to operate the individual electric machine 13 or 23 by drawing electrical energy from the energy store 27 on the one hand and to charge the energy store 27 via the individual electric machine 13 or 23 in its generator mode on the other.

The gear 4 off 2 also has a shaft 28 and an output shaft 29, with the output shaft 29 being offset from the axis of the drive shaft 9 and the two input shafts 10 and 11, while the shaft 28 is coaxial with the drive shaft 9 and the input shafts 10 and 11. In this case, the shaft 28 is designed as a hollow shaft, which axially covers a partial section of the drive shaft 9 and is provided radially between the drive shaft 9 and the first input shaft 10 . The output shaft 29 is permanently coupled to the shaft 28 via a spur gear stage 30 which has a spur gear 31 and a spur gear 32 . The spur gear 31 of the spur gear stage 30 is arranged on the shaft 28 in a rotationally fixed manner and meshes with the spur gear 32 which is provided on the output shaft 29 in a rotationally fixed manner. In addition to the spur gear 32 of the spur gear stage 30, the output shaft 29 also carries a spur gear 33 of a spur gear stage 34 and a spur gear 35. The spur gear 33 of the spur gear stage 34 is permanently in mesh with a spur gear 36 of the spur gear stage 34, with the spur gear 36 being rotatable on the Shaft 28 is mounted. The spur gear 35 meshes with a drive ring gear 37 of the differential gear 5 lying parallel to the axis and forms a spur gear stage 38 with it, the drive ring gear 37 also defining an output side 39 of the gear 4 .

As in 2 can be seen, the transmission 4 also includes a planetary stage 40, which consists of a first element 41, a second element 42 and a third element 43 together. The first element 41 is formed by a sun gear 44, the second element 42 by a planet carrier 45 and the third element 43 by a ring gear 46. In this case, the planet carrier 45 supports a plurality of planet gears which are in toothed engagement with the radially inner sun gear 44 and with the radially surrounding ring gear 46 . In this respect, the planetary stage 40 is designed as a minus planetary gear set. The planetary stage 40 is also placed coaxially with the input shafts 10 and 11 and also the drive shaft 9, with the planetary stage 40 being arranged essentially overlapping the second electric machine 23 axially and lying radially on the inside of the latter.

In principle, within the scope of the invention, an embodiment of the planetary stage 40 as a plus planetary gearset is also possible, with a planetary carrier guiding rotatably mounted at least one pair of planetary gears in a plus planetary gearset, of which planetary gears a planetary gear with a sun gear and a planetary gear with a ring gear meshing with one another stands and the planet gears also mesh with each other. Furthermore, in comparison to the design as a minus planetary gearset, a connection of the ring gear and a connection of the planet carrier would have to be exchanged and a static gear ratio of the planetary stage would have to be increased by one.

In the present case, the first element 41 of the planetary stage 40 is connected to the second input shaft 11 in a torque-proof manner, while the third element 43 of the planetary stage 40 is connected to the drive shaft 9 in a torque-proof manner. In addition, the transmission 4 has five shifting elements A, B, C, D and G, with the shifting elements A, B, C and D being designed as positive shifting elements in the form of claw shifting elements and present as clutches. On the other hand, the switching element G is a brake or a freewheeling brake which, in the latter case, prevents the drive shaft 9 from rotating in one direction and thereby prevents the internal combustion engine 2 from rotating backwards.

When actuated, the switching element A connects the first input shaft 10 to the shaft 28 in a rotationally fixed manner, as a result of which the first input shaft 10 is then also coupled to the output shaft 29 via the spur gear stage 30 . On the other hand, the switching element B in the closed state causes a non-rotatable connection of the spur gear 36 of the spur gear stage 34 to the first input shaft 10, as a result of which the first input shaft 10 is subsequently coupled to the output shaft 29 via the spur gear stage 34.

The spur gear 36 of the spur gear stage 34 can also be connected in a torque-proof manner to the second element 42 of the planetary stage 40 by closing the switching element C, as a result of which the spur gear stage 34 then couples the output shaft 29 to the second element 42 of the planetary stage 40. In addition, the second element 42 of the planetary stage 40 can also be connected in a torque-proof manner to the shaft 28 via the shifting element D by actuating it, so that the second element 42 of the planetary stage 40 is subsequently coupled to the output shaft 29 via the spur gear stage 30.

The shifting element A and the shifting element B are combined here to form a shifting device 47, via whose actuating device (not shown in detail here) both the shifting element A and the shifting element B can be transferred from a neutral position into a closed state. The switching element C and the switching element D also form a switching device 48, in which the switching element C on the one hand and the switching element D on the other hand can be actuated from a neutral position via a common actuating device.

On an axial end of the transmission 4, on which this is connected to the drive shaft 9 on the torsional vibration damper 3 and on which the spur gear stage 38 and the output side 39 are also provided, the shifting element G follows axially first, then the spur gear stage 15 and the spur gear stage 30 essentially in one gear plane, then the spur gear stage 16, then the first electric machine 13 and axially overlapping the shifting device 47 and the spur gear stage 34 and the shifting device 48, and finally the second electric machine 23 and the planetary stage 40.

In 3 1 is an example shift pattern for transmission 4 2 tabulated. As can be seen, different gears E1, E2, E3 and E4 can be implemented here, with an X in the columns of the shifting pattern indicating which of the shifting elements A, B, C, D and G is closed.

As in 3 As can be seen, a first gear E1 is shifted between the first input shaft 10 and the output side 39 by closing the shifting element A, so that the first input shaft 10 is then non-rotatably coupled to the shaft 28 and thus to the output shaft 29 via the spur gear stage 30 is. The result of this is that the rotor of the first electric machine 13 is connected to the output side 39 via the spur gear stages 15 and 16, the spur gear stage 30 and the spur gear stage 38. A second gear E2 then arises between rule first input shaft 10 and the output side 29 by closing the switching element B, whereby the first input shaft 10 is then coupled via the spur gear 34 to the output shaft 29. In contrast to the first gear E1, there is then a coupling between the rotor 12 of the electric machine 13 and the output side 39 via the spur gear stages 15 and 16, the spur gear stage 34 and the spur gear stage 38. The two gears E1 and E2 can be used in an electric motor operation of the first Electric machine 13 can be used to drive the motor vehicle via the first electric machine 13, while in the two gears E1 and E2 in generator operation of the first electric machine 13 and during braking of the motor vehicle charging of the energy store 27 can be displayed (recuperation).

In addition, a first gear E3 results between the second input shaft 11 and the output side 39 by simultaneously actuating the shifting elements D and G, so that the second element 42 of the planetary stage 40 is non-rotatably connected to the shaft 28 and via this by means of the spur gear stage 30 to the output shaft 29 is coupled, while the third element 43 of the planetary stage 40 is fixed together with the drive shaft 9 via the switching element G. As a result, the second input shaft 11 and thus also the rotor 24 of the second electric machine 23 are then coupled via the planetary stage 40 to the shaft 28 and further via the spur gear stage 30 and the spur gear stage 38 to the output side. A second gear E4 can be achieved between the second input shaft 11 and the output side 39 by closing the shifting elements C and G, whereby the third element 43 of the planetary stage 40 and the drive shaft 9 are again fixed, while the second element 42 of the planetary stage 40 is now over the spur gear stage 34 is connected to the output shaft 29 . As a result, the rotor 24 of the second electric machine 23 is then coupled to the output side 39 via the planetary stage 40, the spur gear stage 34 and the spur gear stage 38. In electric motor operation of the second electric machine 23, the two gears E3 and E4 can be used to drive the motor vehicle and in generator mode of the second electric machine 23 during braking of the motor vehicle to charge the energy store 27.

About the gear 4 out 2 different operating modes I to XVII of the motor vehicle drive train 1 can be realized, which in 4 are shown in tabular form: in an operating mode I, the switching element D is actuated in order to carry out a charging operation or a starting of the internal combustion engine. The former is implemented in that the internal combustion engine 2 drives the third element 43 of the planetary stage 40 via the drive shaft 9, while the first element 41 of the planetary stage 40 drives the second electric machine 23 working as a generator and supports it via the vehicle mass on the second element 42 of the planetary stage 40 takes place. For this purpose, the output side 39 is coupled to the second element 42 of the planetary stage 40 via the spur gear stage 38 and the spur gear stage 30 by means of the shaft 28 . To start the internal combustion engine 2, on the other hand, the second electric machine 23 is driven as an electric motor and an output is made via the third element 43 of the planetary stage 40 to the drive shaft 9 and thus to the internal combustion engine 2 in order to start it.

Charging or starting operation can also be implemented in an operating mode II, in which case the switching element C is switched to a closed state. Analogously to what is described for operating mode I, the electrical energy store 27 can be charged when the second electric machine 23 is operated as a generator, whereas the internal combustion engine 2 can be started when the second electric machine 23 is operated as an electric motor. In contrast to operating mode I, the second element 42 of the planetary stage 40 is coupled to the output side 39 via the spur gear stage 34 instead of the spur gear stage 30.

In an operating mode III, an electrodynamic starting in the forward direction can be represented by the interaction of the internal combustion engine 2 and the second electric machine 23 . To do this, the shifting element D is actuated, with the internal combustion engine 2 subsequently driving the third element 43 of the planetary stage 40 via the drive shaft 9, while the second electric machine 23 is supported on the first element 41 of the planetary stage 40 and an output via the second element 42 of the planetary stage 40 onto the shaft 28 and from there further via the spur gear stage 30 and the spur gear stage 38 to the output side 39 . Electrodynamic starting is also implemented in operating mode IV, which largely corresponds to operating mode III, with the difference that, starting from the second element 42 of the planetary stage 40, an output via the spur gear stage 34 and then via the spur gear stage 38 to the output side 39 takes place.

In operating modes V to VIII, purely electric driving is then implemented in each case by shifting one of the gears E1 to E4, as already mentioned 3 has been described. For this purpose, the respectively integrated electric machine 13 or 23 is operated as an electric motor.

In operating modes IX to XII, both electric machines 13 and 23 are then integrated together in order to drive the motor vehicle via both electric machines 13 and 23 in their electric motor operation. For this purpose, the gears E1 to E4 are combined with one another by using gears E1 and E3 simultaneously in operating mode IX, gears E1 and E4 simultaneously in operating mode X, gears E2 and E3 simultaneously in operating mode XI and gears E2 and E3 simultaneously in operating mode XII Gears E2 and E4 are switched.

As also in 4 As can be seen, in the operating modes XIII to XVII, an electrodynamic starting is implemented analogously to one of the two operating modes III and IV and at the same time one of the two gears E1 or E2 is shifted. In this respect, the motor vehicle can be started up through the interaction of the internal combustion engine 2 and the second electric machine 23, with the first electric machine 13 also being coupled to the output side 37 and being able to provide support here. The two operating modes XIII and XIV correspond to one another in terms of switching, but in operating mode XIV the motor vehicle is preferably started off in the reverse direction.

5 FIG. 1 shows a schematic representation of a part of the motor vehicle drive train 1 1 , Which in this case, however, has a gear 4 'according to a second embodiment of the invention. This configuration option essentially corresponds to the variant from FIG 2 , with the difference that now two further shifting elements E and F are provided, of which shifting element E, when actuated, fixes the first element 41 of the planetary stage 40 and thus also the second input shaft 11 on the transmission housing 8 and consequently prevents it from rotating. In contrast, the switching element F in the closed state connects the drive shaft 9 and the second input shaft 11 and thus also the third element 43 and the first element 41 of the planetary stage 40 in a torque-proof manner with one another, so that the planetary stage 40 is blocked. The shifting elements E and F are preferably designed as positive-locking shifting elements and in this case in particular as a claw shifting element, with the shifting element F being designed as a clutch and the shifting element E as a brake.

The switching elements E and F are presently combined to form a switching device 49, via whose actuating device - not shown in detail here - switching element E on the one hand and switching element F on the other can be transferred into a respective actuated state from a neutral position. The switching device 49 is arranged axially on an axial end of the transmission 4 ′ opposite the connection to the torsional vibration damper 3 . For the rest, the configuration option corresponds to 5 according to the variant 2 , so that reference is made to what has been described here.

6 FIG. 1 shows a schematic representation of a part of the motor vehicle drive train 1 1 with a gear 4" according to a third embodiment of the invention. This embodiment essentially corresponds to the previous variant 5 In contrast to this, in a planetary stage 40' a first element 41' is still formed by a sun gear 44', but now a second element 42' is present as a ring gear 46' and a third element 43' as a planet carrier 45'. In this respect, the drive shaft 9 is now non-rotatably connected to the planet carrier 45` of the planetary stage 40', while the ring gear 46' can be non-rotatably connected via the switching element C to the spur gear 36 of the spur gear stage 34 and by means of the switching element D non-rotatably to the shaft 28. In addition, the 2-stage connection of the rotor shaft 21 of the first electric machine 13 is realized in that the spur gear 17 now meshes with a spur gear 50 , which also meshes with the spur gear 20 at the same time. Otherwise, the variant corresponds to 6 according to the previous variant 5 , so that what is described here is referred to.

7 shows an exemplary shift pattern of the transmission 4' 5 and also the gear 4" after 6 , where this shift pattern largely from the shift pattern 3 is equivalent to. The gears E1 to E4 can also be implemented as gears in the gear 4' or 4"; 3 Described each reference is made. In addition, however, the gears V1 to V4 can also be realized, whereby the shifting elements D and E are actuated to produce the gear V1 effective between the input shaft 9 and the output side 39, whereby the second input shaft 11 and thus also the first element 41 or 41 'of the planetary stage 40 or 40' is fixed, so that the drive shaft 9 is coupled via the planetary stage 40 or 40' and further via the spur gear stage 30 and the spur gear stage 38 to the output side 39. As a result, the motor vehicle can be driven via the internal combustion engine 2 .

Likewise, in a gear V2, a drive can also take place via the internal combustion engine 2, with the shifting elements D and F being actuated to produce the gear V2. As a result, the drive shaft 9 is non-rotatably connected to the second via the then locked planetary stage 40 or 40' Element 42 or 42 'connected and then coupled via the spur gear 30 and the spur gear 38 with the output side 39.

In gear V3, the shifting elements C and E are to be closed simultaneously, whereby, as in gear V1, the drive shaft 9 is connected to the second element 42 and 42' respectively. In contrast to gear V1, however, there is then an output from the second element 42 or 42' to the output shaft 29 via the spur gear stage 34. The drive shaft 9 is then also coupled to the output side 39 in gear V4 via the same spur gear stage 34, In contrast to gear V3, however, shifting element F is actuated instead of shifting element E, so that planetary stage 40 or 40' is blocked.

Also after the motor vehicle drive train 5 or after 6 With the respective gear 4 'or 4 ", different operating modes can be realized, which in 8th are presented in tabular form. In addition to the operating modes I to XVII, which are already 4 have been described in advance, additional operating modes XVIII to XXXII can also be presented, which will now be briefly described in detail: in operating mode XVIII, the internal combustion engine 2 can again be started or the energy storage device can be charged by closing the switching element F , since in this case the drive shaft 9 and the second input shaft 11 are connected to one another in a torque-proof manner via the then blocked planetary stage 40 or 40'. If the second electric machine 23 is operated as a generator, the energy accumulator can be charged when it is driven by the internal combustion engine 2, while the internal combustion engine 2 can be started when the second electric machine 23 is operated as an electric motor.

In the operating modes XIX to XXII, pure driving via the internal combustion engine 2 then takes place by shifting one of the gears V1 to V4, with the shifting of these gears already closing 7 has been described. In the two operating modes XXIII and XXIV, serial driving is then implemented in each case by driving via the first electric machine 13, with current being generated at the same time by coupling the internal combustion engine 2 to the second electric machine 23 by closing the switching element F in generator operation of the second electric machine 23 is produced. In this way, all or at least part of the electricity required for electric driving can be generated. In operating mode XXIII, gear E1 is shifted, while in operating mode XXIV driving takes place in gear E2.

In the other operating modes XXV to XXXII, the gears E1 and E2 are then combined with the gears V1 to V4 and sometimes also the gears E3 and E4 in order to simultaneously use the first electric machine 13, the internal combustion engine 2 and possibly also the second electric machine 23 to be able to drive. An additional drive via the second electric machine 23 is possible in the operating modes XXVI, XXVIII, XXX and XXXII, since one of the two gears E3 or E4 is switched and the second input shaft 11 is not locked via the switching element E.

By means of the configurations according to the invention, a compactly constructed transmission can be realized with low manufacturing costs.

Reference List

1

automotive powertrain

2

internal combustion engine

3

torsional vibration damper

4, 4', 4"

transmission

5

differential gear

6

drive wheel

7

drive wheel

8th

gear case

9

drive shaft

10

input shaft

11

another input shaft

12

rotor

13

electric machine

14

stator

15

spur gear stage

16

spur gear stage

17

spur gear

18

spur gear

19

spur gear

20

spur gear

21

rotor shaft

22

Wave

23

electric machine

24

rotor

25

stator

26

control device

27

energy storage

28

Wave

29

output shaft

30

spur gear stage

31

spur gear

32

spur gear

33

spur gear

34

spur gear stage

35

spur gear

36

spur gear

37

drive ring gear

38

spur gear stage

39

output side

40, 40'

planetary stage

41, 41'

first item

42, 42'

second element

43, 43`

third element

44, 44`

sun gear

45, 45`

planetary web

46, 46'

ring gear

47

switching device

48

switching device

49

switching device

50

spur gear

A

switching element

B

switching element

C

switching element

D

switching element

E

switching element

f

switching element

G

switching element

V1

corridor

v2

corridor

V3

corridor

V4

corridor

E1

corridor

E2

corridor

E3

corridor

E4

corridor

I to XXXII

operating modes

Claims (17)

Transmission (4; 4';4") for a motor vehicle, comprising a drive shaft (9) which is set up to connect the transmission (4; 4';4") to a drive engine of the motor vehicle, a first input shaft (10 ), which is coupled to a rotor (12) of a first electric machine (13), and an output shaft (29), which is coupled to an output side (39), wherein the first input shaft (10) on the one hand by closing a first switching element ( A) can be connected to the output shaft (29) via a first spur gear stage (30) and on the other hand by actuating a second switching element (B) via a second spur gear stage (34), with a planetary stage (40; 40') having a first element (41; 41'), a second element (42; 42') and a third element (43; 43') in the form of a sun gear (44; 44'), a planet carrier (45; 45') and a ring gear (46 ; 46') is provided, wherein the third element (43; 43') of the planetary stage (40; 40') is non-rotatably connected to the drive shaft (9), and wherein a third shifting element (C), a fourth shifting element (D) and a fifth switching element (G) are provided, wherein the drive shaft (9) can be fixed via the fifth switching element (G), characterized in that the first element (41; 41') of the planetary stage (40; 40') is connected in a rotationally fixed manner to a second input shaft (11) which is coupled to a rotor (24) of a second electric machine (23), whereas the second element (42; 42') of the Planetary stage (40; 40') can be coupled to the output shaft (29) on the one hand by closing the third switching element (C) via the second spur gear stage (34) and on the other hand by actuating the fourth switching element (D) via the first spur gear stage (30). is. Gear (4; 4';4") after claim 1 , characterized in that - a first gear (E1) between the first input shaft (10) and the output shaft (29) by closing the first shifting element (A), - a second gear (E2) between the first input shaft (10) and of the output shaft (29) by actuating the second shifting element (B), - a first gear (E3) between the second input shaft (11) and the output shaft (29) by locking the fourth (D) and the fifth shifting element (G), and - A second gear (E4) between the second input shaft (11) and the output shaft (29) by actuating the third (C) and the fifth switching element (G) results. Gear (4; 4';4") after claim 1 or 2 , characterized in that also a six tes switching element (E) and a seventh switching element (F) are provided, wherein the sixth switching element (E) fixes the first element (41; 41') of the planetary stage (40; 40') when actuated, whereas by actuating the seventh switching element ( F) two of the elements (41, 42, 43; 41', 42', 43') of the planetary stage (40; 40') can be connected to one another in a torque-proof manner. Gear (4; 4';4") after claim 3 , characterized in that - a first gear (V1) between the drive shaft (9) and the output shaft (29) by closing the fourth (D) and the sixth switching element (E), - a second gear (V2) between the drive shaft (9) and the output shaft (29) by actuating the fourth (D) and the seventh switching element (F), - a third gear (V3) between the drive shaft (9) and the output shaft (29) by engaging the third (C) and the sixth shifting element (E), and - a fourth gear (V4) between the drive shaft (9) and the output shaft (29) by actuating the third (C) and the seventh shifting element (F). Transmission (4; 4';4") according to one of the preceding claims, characterized in that the first spur gear stage (30) comprises a first spur gear (31) which is placed on a shaft (28) in a torque-proof manner and is connected to a second spur gear ( 32) of the first spur gear stage (30) is in toothed engagement, which is arranged in a rotationally fixed manner on the output shaft (29), the shaft (28) being rotationally fixed to the first input shaft (10) via the first switching element (A) and by means of the fourth switching element ( D) can be connected in a torque-proof manner to the second element (42; 42') of the planetary stage (40; 40'). Transmission (4; 4';4") according to one of the preceding claims, characterized in that the second spur gear stage (34) comprises a first spur gear (36) which meshes with a second spur gear (33) of the second spur gear stage (34), which is arranged non-rotatably on the output shaft (29), the first spur gear (36) of the second spur gear stage (34) being non-rotatable with the first input shaft (10) via the second shift element (B) and non-rotatable with the third shift element (C). second element (42; 42') of the planetary stage (40; 40') can be connected. Transmission (4; 4') according to one of the preceding claims, characterized in that the first element (41) of the planetary stage (40) the sun wheel (44), the second element (42) of the planetary stage (40) when the planetary stage ( 40) as a minus planetary gear set, the planet carrier (45) and when the planetary stage is designed as a plus planetary gear set, the ring gear and the third element (43) of the planetary stage (40) when the planetary stage (40) is designed as a minus planetary gear set, the ring gear (46) and when the planetary stage is designed as a plus planetary set, it is the planetary web. Gear (4") according to one of Claims 1 until 6 , characterized in that the first element (41 ') of the planetary stage (40') the sun gear (44`), the second element (42 ') of the planetary stage (40') when the planetary stage (40 ') as a minus planetary set the ring gear (46') and when the planetary stage is designed as a plus planetary gear train, the planetary carrier and the third element (43') of the planetary stage (40') when the planetary stage (40') is designed as a negative planetary gear train, the planetary carrier (45') and the ring gear is when the planetary stage is designed as a plus planetary set. Transmission (4; 4';4") according to one of the preceding claims, characterized in that the individual shifting element (A, B, C, D; A, B, C, D, E, F) is designed as a positive-locking shifting element. Transmission (4; 4';4") according to one of the preceding claims, characterized in that the rotor (12) of the first electric machine (13) is arranged coaxially or off-axis to the first input shaft (10). Transmission (4; 4';4") according to one of the preceding claims, characterized in that the rotor (24) of the second electric machine (23) is placed coaxially or off-axis to the second input shaft (11). Transmission (4; 4';4") according to one of the preceding claims, characterized in that the first shifting element (A) and the second shifting element (B) are combined to form a shifting device (47). Transmission (4; 4';4") according to one of the preceding claims, characterized in that the third shifting element (C) and the fourth shifting element (D) are combined to form a shifting device (48). gear (4';4") claim 3 , characterized in that the sixth switching element (E) and the seventh switching element (F) are combined to form a switching device (49). Motor vehicle drive train (1) for an electric or hybrid vehicle, comprising a transmission (4; 4';4") according to one or more of Claims 1 until 14 . Method for operating a gear (4; 4';4") claim 1 , characterized in that only the third switching element (C) or the fourth switching element (D) is closed to represent a charging operation or a starting operation. Method for operating a gear (4; 4';4") claim 1 , characterized in that the third switching element (C) or the fourth switching element (D) is closed to represent a starting mode when driven via the drive shaft (9).

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