Motor vehicle transmission for an at least partially electrically powered motor vehicle

Abstract

The invention relates to a motor vehicle transmission (2), comprising a first input shaft (9), a second input shaft (10), an output shaft (11), a first planetary gear set (P1) and a second planetary gear set (P2), wherein the input shafts (9, 10) are each provided for coupling to a respective drive motor. Furthermore, at least functionally, three shifting elements are provided in the form of a first shifting element (B), a second shifting element (D), and a third shifting element (E). Furthermore, the invention relates to a drive unit (1), a motor vehicle drive axle, a hybrid or electric vehicle, and a method for operating a motor vehicle transmission.

Description

[0001] The invention relates to a motor vehicle transmission for an at least partially electrically driven motor vehicle, comprising a first drive shaft, an output shaft, and a first planetary gear set and a second planetary gear set, wherein the first drive shaft is provided for coupling to a first drive machine, in particular a first electric machine, wherein the first planetary gear set and the second planetary gear set each have a first element, a second element, and a third element in the form of a sun gear, a planet carrier, and a ring gear, at least functionally a first shifting element, a second shifting element, and a third shifting element are provided, wherein the first element of the first planetary gear set and the first element of the second planetary gear set are connected in a rotationally fixed manner to the first drive shaft,The second element of the second planetary gear set is connected to the output shaft in a rotationally fixed manner, the second element of the first planetary gear set and the third element of the second planetary gear set being connected to one another in a rotationally fixed manner, and the at least functionally provided first shifting element being configured to lock the third element of the first planetary gear set in an actuated state. Furthermore, the invention relates to a drive unit for an at least partially electrically driven motor vehicle, a motor vehicle drive axle for a hybrid or electric vehicle, a hybrid or electric vehicle, and methods for operating a motor vehicle transmission and a drive unit.

[0002] In electric and hybrid motor vehicles, a motor vehicle transmission is sometimes provided in the respective drivetrain between at least one electric motor and the drive wheels of the respective motor vehicle, in order to be able to translate the drive movement of the at least one electric motor, particularly at low speed, to the drive wheels. In addition to single-gear transmissions, motor vehicle transmissions are also sometimes used in which two or more gears can be engaged.

[0003] US 4,702,125 A discloses a drive unit for an electric vehicle, wherein this drive unit consists of a motor vehicle transmission and an electric motor connected to a drive shaft of the motor vehicle transmission. Furthermore, the motor vehicle transmission has two planetary gear sets, each formed by a sun gear, a planetary carrier, and a ring gear. Furthermore, in a variant of US 4,702,125 A, the motor vehicle transmission is provided with three shifting elements, the selective actuation of which can establish different power flow paths between the drive shaft and an output shaft of the motor vehicle transmission. The output shaft is then coupled to a differential gear via another planetary gear set.

[0004] Based on the prior art described above, the object of the present invention is to realize a motor vehicle transmission via which two drive motors can be integrated in a suitable manner.

[0005] This object is achieved starting from the preamble of claim 1 in conjunction with its characterizing features. The dependent claims following therefrom each represent advantageous developments of the invention. A drive unit in which a motor vehicle transmission according to the invention is provided is further the subject of claim 14. Furthermore, claim 15 relates to a motor vehicle drive axle for a hybrid or electric vehicle, while claim 16 relates to a hybrid or electric vehicle. Finally, claims 17 to 21 each relate to a method for operating a motor vehicle transmission according to the invention, and claims 22 to 24 each relate to a method for operating a drive unit.

[0006] According to the invention, a motor vehicle transmission comprises a first drive shaft, an output shaft, and a first planetary gear set and a second planetary gear set. The first drive shaft is provided for coupling to a first drive machine, in particular a first electric machine. In addition, the first planetary gear set and the second planetary gear set each have a first element, a second element, and a third element in the form of a sun gear, a planet carrier, and a ring gear, respectively, wherein a first shifting element, a second shifting element, and a third shifting element are further provided, at least functionally. The first element of the first planetary gear set and the first element of the second planetary gear set are connected in a rotationally fixed manner to the first drive shaft, whereas the second element of the second planetary gear set is connected in a rotationally fixed manner to the output shaft.Furthermore, the second element of the first planetary gear set and the third element of the second planetary gear set are connected to one another in a rotationally fixed manner. The first shifting element, which is at least functionally provided, is configured to lock the third element of the first planetary gear set in an actuated state.

[0007] For the purposes of the invention, "axial" refers to an orientation in the direction of a longitudinal center axis of the motor vehicle transmission, parallel to which the rotational axes of the shafts of the motor vehicle transmission and the elements of the planetary gear sets are also oriented. "Radial" then refers to an orientation in the diameter direction of a respective component of the transmission, in particular a respective shaft or element of the planetary gear sets.

[0008] The first planetary gear set and the second planetary gear set each consist of a first element, a second element and a third element, wherein the elements of the respective planetary gear set are each formed by a sun gear, a planet carrier and a ring gear. Particularly preferably, the first planetary gear set and the second planetary gear set are in the form of a minus planetary set, in which the respective planet carrier rotatably supports at least one planet gear, wherein the at least one planet gear meshes with both the respective sun gear and the respective ring gear. In one embodiment of the first planetary gear set orof the second planetary gear set as a minus planetary gear set, the first element of the respective planetary gear set is then in particular the respective sun gear, the second element of the respective planetary gear set is the respective planet carrier and the third element of the respective planetary gear set is the respective ring gear.

[0009] Alternatively, the first planetary gear set and / or the second planetary gear set could in principle also be designed as a plus planetary gear set. In this case, at least one planetary gear pair is rotatably mounted in the respective planet carrier, of which one planetary gear meshes with the respective sun gear and one planetary gear meshes with the respective ring gear. In addition, the planetary gears of the at least one planetary gear pair mesh with one another. In contrast to a design as a minus planetary gear set, the first element of the respective planetary gear set is then preferably the sun gear, the second element of the respective planetary gear set is the ring gear, and the third element of the respective planetary gear set is the planet carrier. In comparison to a design as a minus planetary gear set, the stationary gear ratio of the respective planetary gear set must also be increased by one.As already described above, in the sense of the invention, both the first planetary gear set and the second planetary gear set are preferably designed as minus planetary gear sets.

[0010] The invention now encompasses the technical teaching that a second drive shaft is provided, which serves for coupling to a second drive motor, in particular a second electric motor. The at least functionally provided second shifting element is also configured to connect the second drive shaft to the third element of the first planetary gear set in an actuated state in a rotationally fixed manner, whereas the at least functionally provided third shifting element is configured to connect the second drive shaft to the first drive shaft in an actuated state in a rotationally fixed manner.

[0011] A “shaft”, such as the respective drive shaft or output shaft, is understood in the sense of the invention to be a rotatable component of the transmission via which a power flow can be guided between components, possibly with the simultaneous actuation of an at least functionally provided switching element. The respective shaft can connect the components axially or radially, or even both axially and radially. The respective shaft can also be in the form of an intermediate piece via which a respective component is connected, for example, purely radially. Furthermore, depending on its course and connection to the components or the ability to connect to them, the respective shaft can be designed as a solid shaft, a hollow shaft, or partly as a solid and partly as a hollow shaft. Alternatively or additionally, the respective shaft can be designed in one or more parts.

[0012] The motor vehicle transmission according to the invention has a first drive shaft and a second drive shaft, wherein the two drive shafts are arranged, in particular, coaxially with one another. In particular, the first drive shaft and the second drive shaft are each assigned to a sub-transmission of the transmission, via which a power flow can be guided from the respective drive shaft to the output shaft. The respective power flow is preferably implemented by the selective actuation of the at least functionally provided shifting elements.

[0013] The first drive shaft and the second drive shaft in the motor vehicle transmission according to the invention are each provided to establish a drive-side coupling to a respective drive machine, wherein the respective drive shaft preferably serves the respective coupling to exactly one respective drive machine. For this purpose, the respective drive shaft is in particular equipped with a connection point at which a coupling of the respective drive shaft to the associated drive machine can be formed. The connection of the associated drive machine to the respective connection point of the respective drive shaft is in particular permanent in the installed state of the motor vehicle transmission, preferably when the associated drive machine is designed as an electric machine. Alternatively, however, an intermediate starting element, such as a hydrodynamic torque converter, a starting clutch, etc., can also be used., via which the respective drive shaft can be or is coupled at its one connection point to the associated upstream drive motor. This is particularly achieved when the associated drive motor is designed as an internal combustion engine.

[0014] The coupling between the associated drive motor and the respective drive shaft is preferably in such a way that, in the installed state of the motor vehicle transmission and when the coupling is established, a fixed speed ratio always prevails between a speed of the respective drive shaft of the motor vehicle transmission and a speed of the associated drive motor. Thus, within the scope of the invention, at least one further transmission stage, such as a spur gear stage and / or a planetary gear stage, can be provided between the respective drive shaft and the associated drive motor, via which a pre-transmission of a rotary movement of the associated drive motor to the respective drive shaft can be represented. However, the respective drive shaft preferably serves as a rotationally fixed connection to the associated drive motor.

[0015] The motor vehicle transmission is, in particular, a hybrid or electric vehicle transmission, which is intended to be connected to a respective drive unit in the form of an electric motor at the respective drive shaft. A respective rotor of the respective electric motor can, as described above, be coupled to the respective drive shaft of the motor vehicle transmission via at least one intermediate gear ratio. However, a respective rotor of the respective electric motor is particularly preferably connected in a rotationally fixed manner to the associated drive shaft in the installed state of the motor vehicle transmission according to the invention.

[0016] In the motor vehicle transmission according to the invention, the output shaft is provided, in particular, to establish an output-side coupling of the motor vehicle transmission to components which, when the motor vehicle transmission is installed, follow the motor vehicle transmission in the direction of power flow to the drive wheels of the respective motor vehicle. Accordingly, the motor vehicle transmission according to the invention is, in particular, a drive transmission via which a coupling of the associated drive motor connected to the respective drive shaft to the drive wheels of the respective motor vehicle can be established in order to transmit a drive movement generated by the respective drive motor to the drive wheels with different transmission ratios.

[0017] The output shaft is preferably coupled to an input element of a differential gear set, which couples the output shaft to two output shafts. As a result, the output shaft is drivingly coupled to the two output shafts via the differential gear set. This advantageously allows a drive torque generated at the output shaft to be distributed between the two output shafts, with the differential gear set also being able to equalize the speed between the output shafts. The differential gear set functions in particular as a transverse differential and is preferably designed in the manner of a bevel gear differential. The transverse differential thus formed is preferably used to distribute a drive movement transmitted to the output shaft of the motor vehicle transmission to the output shafts, which are preferably assigned to a motor vehicle drive axle.However, the differential gear set can also function as a longitudinal differential, which can be used to distribute drive power across multiple drive axles. As an alternative to a bevel gear differential, the differential gear set can also be designed as a planetary gear differential, a spur gear differential, etc., within the scope of the invention.

[0018] The input element to which the output shaft is coupled is preferably a differential cage of the differential gear set. When the differential gear set is used as a transverse differential and the motor vehicle transmission is installed transversely to a direction of travel of the associated motor vehicle, the output shaft is then preferably connected to the input element in a rotationally fixed manner. This is also achieved in particular when the differential gear set functions as a longitudinal differential and the motor vehicle transmission is aligned in the direction of travel of the motor vehicle. In the preferred installation of the motor vehicle transmission in the direction of travel and use of the differential gear set as a transverse differential, the output shaft is coupled to the input element via a bevel drive.Such a bevel drive is also preferably used when the differential gear set is a longitudinal differential and the motor vehicle transmission is aligned transversely to the direction of travel.

[0019] In the motor vehicle transmission according to the invention, the drive shafts and the output shaft are arranged, in particular, coaxially to one another, with the planetary gear sets also preferably being positioned coaxially to the drive shafts and the output shaft. This allows for a particularly compact design of the motor vehicle transmission in the radial direction.

[0020] In the motor vehicle transmission according to the invention, the first element of the first planetary gear set, the first element of the second planetary gear set, and the first input shaft are permanently connected to one another in a rotationally fixed manner, whereby the first input shaft, the first element of the first planetary gear set, and the first element of the second planetary gear set constantly rotate together. Furthermore, the second element of the first planetary gear set and the third element of the second planetary gear set are permanently connected to one another in a rotationally fixed manner, which always means a joint rotation of the second element of the first planetary gear set and the third element of the second planetary gear set. There is also a permanently rotationally fixed connection between the output shaft and the second element of the second planetary gear set, whereby the output shaft and the second element of the second planetary gear set constantly rotate together.

[0021] An actuated state of the at least functionally provided first shifting element results in the third element of the first planetary gear set becoming stuck, whereby the third element of the first planetary gear set is then prevented from rotating. If, on the other hand, an actuated state of the at least functionally provided second shifting element is represented, the second drive shaft and the third element of the first planetary gear set are connected to one another in a rotationally fixed manner, which results in a joint rotation of the second drive shaft and the third element of the first planetary gear set. An actuated state of the at least functionally provided third shifting element brings about a rotationally fixed connection between the two drive shafts, whereby the two drive shafts then rotate together.

[0022] The motor vehicle transmission according to the invention has, at least functionally, a first shifting element, a second shifting element and a third shifting element, through the selective actuation of which different power flow patterns can be realized in the motor vehicle transmission according to the invention. Within the scope of the invention, exactly these three shifting elements can be present in the motor vehicle transmission according to the invention for shifting different gears, at least in terms of function, although at least one further shifting element is preferably provided, at least functionally, for shifting further gears. The fact that a respective shifting element is provided "at least functionally" means, within the meaning of the invention, that at least the respective function of the respective shifting element is represented in the motor vehicle transmission according to the invention.The individual switching elements can actually be physically present as individual switching elements, or their function can be implemented by another component, such as a switching device. A component implementing the function can then combine the functions of two or more switching elements into one device.

[0023] The design of a motor vehicle transmission according to the invention has the advantage that it achieves a structure of the motor vehicle transmission in which different coupling options of the two drive shafts with the output shaft are provided and thus, in the installed state of the motor vehicle transmission, suitable integration of the drive machine connected to the drive shafts is also possible.

[0024] Thus, the motor vehicle transmission according to the invention can be operated in such a way that a gear is shifted between the first input shaft and the output shaft by displaying the actuated state of the first shifting element. If only the actuated state of the first shifting element is realized, then only the first drive motor connected to the first input shaft is engaged, while the second drive motor is decoupled. However, the gear can also be shifted simultaneously between both input shafts and the output shaft and thus also be used by the drive motor coupled to the second input shaft by displaying simultaneously actuated states of the first shifting element and the third shifting element.

[0025] Furthermore, in the motor vehicle transmission according to the invention, a superposition operation can also be implemented on the planetary gear sets, in which the two drive shafts are coupled to the output shaft via the first planetary gear set and the second planetary gear set. For this purpose, only an actuated state of the second shifting element needs to be represented. However, this superposition operation can also be used to integrate the drive motors connected to the drive shafts to represent longer driving operation. If, for example, the drive motors connected to the drive shafts have the same speeds, both planetary gear sets rotate in unison, thereby implementing a direct drive from the drive shafts to the output shaft. In this way, a direct gear of the motor vehicle transmission could also be represented in superposition operation.

[0026] For the purposes of the invention, a permanent "rotatable" connection of transmission components means that these components, which are connected or in a rotationally fixed relationship, are rigidly connected to one another and thus always have the same rotational speed. The components, which are connected or in a rotationally fixed relationship, can be separate components that are fastened to one another. Alternatively, components, which are connected or in a rotationally fixed relationship, can also be designed as a single piece and thus form a single component. This is particularly true when these components are arranged spatially close to one another.

[0027] Within the scope of the invention, a fixed state of a component of the motor vehicle transmission is realized in particular by a rotationally fixed connection to a component fixed to the housing, which can be a housing of the motor vehicle transmission, a part of the housing or a component permanently connected thereto in a rotationally fixed manner.

[0028] For the purposes of the invention, securing a component of the motor vehicle transmission via an at least functionally provided shifting element or a rotationally fixed connection between components of the motor vehicle transmission via an at least functionally provided shifting element means that the component in question is not permanently secured or the components in question are not permanently coupled to one another, but rather securing or a rotationally fixed connection is only achieved by representing an actuated state of the at least functionally provided, intermediate shifting element. In this case, an actuated state of the at least functionally provided shifting element for the purposes of the invention means that the shifting element in question is transferred to a closed state and subsequently adjusts the rotational movements of the components directly coupled to it.If at least the function of a positive-locking switching element is depicted, the components directly connected to one another in a rotationally fixed manner will run at the same speed. Whereas, if at least the function of a non-positive switching element is depicted, speed differences between the components may exist even after the actuated state of the switching element is depicted. This intended or unintended state is nevertheless referred to within the scope of the invention as a rotationally fixed connection of the respective components via the at least functionally provided switching element.

[0029] According to one embodiment of the invention, a further shifting element is also provided, at least functionally, which is designed to lock the second element of the first planetary gear set and the third element of the second planetary gear set in an actuated state. The representation of an actuated state of the at least functionally provided further shifting element thus causes the second element of the first planetary gear set and the third element of the second planetary gear set to be locked together and, as a result, prevented from rotating.

[0030] In a motor vehicle transmission designed according to the aforementioned embodiment, a further gear can then be engaged between the first input shaft and the output shaft by displaying the actuated state of the further shifting element. The first input shaft is then coupled to the output shaft via the second planetary gear set. If an actuated state of both the second shifting element and the third shifting element is not displayed, then again only the first drive motor connected to the first input shaft is coupled to the output shaft, while the second drive motor is decoupled. However, the further gear can also be used for both drive motors simultaneously, for which purpose the simultaneously actuated states of the second shifting element and the third shifting element must be displayed.

[0031] Simultaneously with the additional gear engaged between the first input shaft and the output shaft, an intermediate gear can also be engaged between the second input shaft and the output shaft by simultaneously operating the additional shifting element and the second shifting element. As a result, the second input shaft is then coupled to the first input shaft via the first planetary gear set and, subsequently, to the output shaft via the second planetary gear set. This coupling has a lower ratio with respect to the second input shaft than in the first gear and the additional gear.

[0032] In a further development of the aforementioned embodiment, the first shifting element and the further shifting element are formed by a common shifting device which has a coupling element. This coupling element can be transferred into a first shifting state and a second shifting state, wherein the coupling element in its first shifting state functionally maps the actuated state of the first shifting element and fixes the third element of the first planetary gear set. In its second shifting state, however, the coupling element functionally maps the actuated state of the further shifting element and fixes the second element of the first planetary gear set and the third element of the second planetary gear set. In this case, the function of the first shifting element and the further shifting element is therefore jointly mapped by one shifting device, which enables a particularly compact arrangement.In addition, a control actuator can be provided for actuating the switching elements, via which the coupling element can be transferred into its various switching states. Preferably, in addition to the two switching states, the coupling element can also be moved into a neutral state, in which neither an actuated state of the first switching element nor an actuated state of the further switching element is represented by the switching device.

[0033] Preferably, in its two switching states and during axial displacement between its two switching states, the coupling element is guided in a rotationally fixed and axially displaceable manner on a first toothing which is fixed and thus permanently stationary. In its first switching state, the coupling element then additionally engages with a second toothing, which is rotationally fixedly connected to the third element of the first planetary gear set. Furthermore, in its second switching state, the coupling element additionally engages with a third toothing, which is rotationally fixedly connected to the second element of the first planetary gear set and the third element of the second planetary gear set.The coupling element of the shifting device is particularly preferably designed as a sliding sleeve, with the toothings more preferably being designed as claw toothings, so that the shifting device replicates the function of unsynchronized claw shifting elements. Within the scope of the invention, however, the first shifting element and the further shifting element could also be designed as individual shifting elements, with the first shifting element and the further shifting element each being present as a positive-locking shifting element, such as a claw shifting element or locking synchronization, or as a non-positive shifting element, for example, as a multi-disk shifting element.

[0034] According to one possible embodiment of the invention, an additional shifting element is further provided, at least functionally, which is designed, in an actuated state, to connect two of the elements of the first planetary gear set to one another in a rotationally fixed manner, or to connect two of the elements of the second planetary gear set to one another in a rotationally fixed manner, or to connect the third element of the first planetary gear set to the third element of the second planetary gear set in a rotationally fixed manner. This results in the two planetary gear sets becoming locked, since the locking of one planetary gear set also results in the locking of the other planetary gear set due to the coupling of the planetary gear sets to one another.a rotationally fixed connection of a further element of the first planetary gear set with a further element of the second planetary gear set also brings about a common block revolution of the two planetary gear sets due to the already existing connections between the planetary gear sets.

[0035] This allows an additional gear to be implemented in the motor vehicle transmission between the first input shaft and the output shaft by representing the actuated state of the additional shifting element. This is because the first input shaft is connected to the output shaft in a rotationally fixed manner via the two interlocked planetary gear sets, thus creating a rigid through-drive from the first input shaft to the output shaft. If an actuated state of both the second shifting element and the third shifting element is not represented, only the first drive motor connected to the first input shaft is coupled to the output shaft in this additional gear, while the second drive motor is decoupled.However, the additional gear can also be realized simultaneously between the second drive shaft and output shaft by simultaneously representing actuated states of the additional switching element and the second switching element or the third switching element.

[0036] If the motor vehicle transmission according to the invention comprises both the further shifting element and the additional shifting element, the first shifting element, the further shifting element, and the additional shifting element can be formed by a common shifting device comprising a coupling element. The coupling element can be transferred into a first shifting state, a second shifting state, and a third shifting state, respectively, wherein the coupling element, in its first shifting state, functionally replicates the actuated state of the further shifting element and fixes the second element of the first planetary gear set and the third element of the second planetary gear set.In its second switching state, the coupling element functionally replicates the actuated state of the first switching element and fixes the third element of the first planetary gear set. In its third switching state, the coupling element functionally replicates the actuated state of the additional switching element and connects the second element of the first planetary gear set and the third element of the second planetary gear set to the third element of the first planetary gear set in a rotationally fixed manner. Advantageously, the function of the three switching elements is thereby implemented by a single switching device, which, on the one hand, allows for a particularly compact design and, on the other hand, requires only one switching actuator to represent the switching states.In particular, in addition to the switching states, the coupling element can then also be moved into intermediate neutral states in which neither an actuated state of the first switching element, nor an actuated state of the further switching element, nor an actuated state of the additional switching element is represented by the switching device.

[0037] In particular, the coupling element of the switching device described immediately above is guided in a rotationally fixed and axially displaceable manner on a first toothing in its first and second switching states, and during axial displacement between its first and second switching states. In its first switching state, the coupling element, while meshing with the first toothing, additionally engages a second toothing, which is rotationally fixedly connected to the second element of the first planetary gear set and the third element of the second planetary gear set.In its second switching state, the coupling element, with existing tooth engagement with the first toothing, additionally engages in a third toothing which is connected in a rotationally fixed manner to the third element of the first planetary gear set, wherein the coupling element, during an axial displacement between its second and its third switching state, is then guided in a rotationally fixed and axially displaceable manner on the third toothing and, in its third switching state, with existing tooth engagement with the third toothing, additionally engages in the second toothing.

[0038] In the variant described above, the coupling element of the shifting device is also designed, in particular, as a sliding sleeve, with the toothings being designed, in particular, as claw toothings, so that the shifting device replicates the function of unsynchronized claw shifting elements. Alternatively, the first shifting element, the further shifting element, and the additional shifting element can also be designed as individual shifting elements. The first shifting element, the further shifting element, and the additional shifting element can each be designed as a positive-locking shifting element, such as a claw shifting element or locking synchronization, or as a non-positive-locking shifting element, for example, as a multi-disk shifting element.

[0039] If the additional shifting element is present in the motor vehicle transmission and the additional shifting element, which locks the second element of the first planetary gear set and the third element of the second planetary gear set in its actuated state, is either not provided or is designed as a separate shifting element, the first shifting element and the additional shifting element can also be formed by a common shifting device. This shifting device then has a coupling element that can be transferred into a first shifting state and a second shifting state, respectively.In its first switching state, the coupling element functionally maps the actuated state of the first switching element and fixes the third element of the first planetary gear set. In its second switching state, the coupling element functionally maps the actuated state of the additional switching element and connects the second element of the first planetary gear set and the third element of the second planetary gear set to the third element of the first planetary gear set in a rotationally fixed manner. This enables a compact design of the motor vehicle transmission, and a common actuating system can also be provided for representing the actuated states of the first switching element and the additional switching element.Preferably, in addition to the two switching states, the coupling element can also be moved into a neutral state in which neither an actuated state of the first switching element nor an actuated state of the further switching element is represented by the switching device.

[0040] In a further development, the coupling element of the aforementioned switching device is guided in a rotationally fixed and axially displaceable manner on a first toothing in both switching states and during axial displacement between its two switching states, which first toothing is rotationally fixedly connected to the third element of the first planetary gear set. In its first switching state, the coupling element, when meshing with the first toothing, additionally engages with a second, fixed toothing. In contrast, in its second switching state, when meshing with the first toothing, the coupling element additionally engages with a third toothing, which is rotationally fixedly connected to the second element of the first planetary gear set and the third element of the second planetary gear set.Particularly preferably, the coupling element of the shifting device is designed as a sliding sleeve, with the toothings more preferably being designed as claw toothings, so that the shifting device replicates the function of unsynchronized claw shifting elements. Within the scope of the invention, however, the first shifting element and the additional shifting element could also be individual shifting elements, whereby a design as positive-locking shifting elements, for example as claw shifting elements or as locking synchronizers, or also as non-positive shifting elements, such as in particular as multi-disk shifting elements, would be conceivable.

[0041] It is an advantageous embodiment of the invention that the second shifting element and the third shifting element are formed by a common shifting device which has a coupling element. The coupling element of this shifting device can be transferred into a first shifting state and a second shifting state, wherein the coupling element in its first shifting state functionally replicates the actuated state of the second shifting element and connects the second input shaft in a rotationally fixed manner to the third element of the first planetary gear set. In its second shifting state, the coupling element functionally replicates the actuated state of the third shifting element and connects the second input shaft in a rotationally fixed manner to the first input shaft.Advantageously, the function of the second switching element and the third switching element is thereby mapped by the switching device, which, in addition to a compact arrangement, also requires only one actuating actuator. In particular, in addition to the two switching states, the coupling element can then also be moved into a neutral state, in which neither an actuated state of the second switching element nor an actuated state of the third switching element is represented by the switching device.

[0042] In the above embodiment, the coupling element is preferably guided in a rotationally fixed and axially displaceable manner on a first toothing, which is rotationally fixedly connected to the second drive shaft, in each of the two switching states and during an axial displacement between the two switching states. If the coupling element is transferred to its first switching state, the coupling element, while meshing with the first toothing, additionally engages with a second toothing, which is rotationally fixedly connected to the third element of the first planetary gear set. In the second switching state, the coupling element, while meshing with the first toothing, additionally engages with a third toothing, which is rotationally fixedly connected to the first drive shaft.Most preferably, the coupling element of the shifting device is designed as a sliding sleeve, with the toothings being designed, in particular, as claw toothings, so that the shifting device replicates the function of unsynchronized claw shifting elements. Alternatively, the second shifting element and the third shifting element can also be designed as individual shifting elements. The second shifting element and the third shifting element can each be designed as a positive-locking shifting element, such as a claw shifting element or a locking synchronizer, or as a non-positive-locking shifting element, such as a multi-disk shifting element.

[0043] Particularly preferably, in the motor vehicle transmission according to the invention, the shifting elements to be provided are combined to form shifting devices where possible, so that the functions of the respective shifting elements to be provided can be represented by the shifting devices via the associated coupling elements. This makes it possible to achieve a particularly compact design of the motor vehicle transmission. Within the scope of the invention, a discrete axial position of the respective coupling element can be assigned to the respective "shifting state" or the respective "neutral state" of the respective coupling element, wherein the respective "shifting state" or the respective "neutral state" is preferably defined by an axial adjustment range within which the coupling element is to be positioned in order to realize the respective shifting state or the respective neutral state.

[0044] Within the meaning of the invention, however, a design option for the motor vehicle transmission is also conceivable in which the second shifting element and the third shifting element are designed as individual shifting elements. This is because an actuated state of both the second shifting element and the third shifting element can be realized simultaneously, and thus, through the rotationally fixed connection of the first element of the first planetary gear set to the third element of the first planetary gear set, a blocking of both planetary gear sets can be brought about. As a result, a rotationally fixed connection of both drive shafts to the output shaft is then also established, whereby a rigid through-drive from the drive shafts to the output shaft in an additional gear can be realized.

[0045] Preferably, the first planetary gear set is arranged axially between the second planetary gear set on one side and the connection points, at which the drive shafts are to be coupled to the drive motors, on the other side. In this case, the second planetary gear set is located on one axial side of the first planetary gear set, and the connection points, at which the drive shafts are to be coupled to the respective drive motors, are located on the other axial side of the first planetary gear set.

[0046] In a further embodiment of the invention, a further, third planetary gear set is provided, which comprises a first element, a second element, and a third element in the form of a sun gear, a planet carrier, and a ring gear. One of the elements of the third planetary gear set is connected in a rotationally fixed manner to the output shaft, one of the elements of the third planetary gear set is connected in a rotationally fixed manner to an output shaft, and one of the elements of the third planetary gear set is fixed. This advantageously allows for an additional transmission of a drive movement transmitted to the output shaft.

[0047] Particularly preferably, the third planetary gear set is a negative planetary gear set, in which the planet carrier rotatably supports at least one planetary gear, wherein the at least one planetary gear meshes with both the sun gear of the third planetary gear set and the ring gear of the third planetary gear set. When the third planetary gear set is configured as a negative planetary gear set, the first element of the third planetary gear set is the sun gear, the second element of the third planetary gear set is the planet carrier, and the third element of the third planetary gear set is the ring gear.

[0048] Alternatively, the third planetary gear set could also be designed as a positive planetary gear set. In this case, at least one planetary gear pair is rotatably mounted in the planet carrier of the third planetary gear set, of which one planetary gear meshes with the sun gear of the third planetary gear set and one planetary gear meshes with the ring gear of the third planetary gear set. In addition, the planetary gears of the at least one planetary gear pair mesh with one another. In contrast to a design as a negative planetary gear set, the first element of the third planetary gear set is preferably the sun gear, the second element of the third planetary gear set is the ring gear, and the third element of the third planetary gear set is the planet carrier. In addition, compared to a design as a negative planetary gear set, the stationary gear ratio of the third planetary gear set must be increased by one.

[0049] Most preferably, in the third planetary gear set, the first element is connected in a rotationally fixed manner to the output shaft, while the second element of the third planetary gear set is connected in a rotationally fixed manner to the output shaft and the third element of the third planetary gear set is permanently fixed.

[0050] The invention also relates to a drive unit which, in addition to a first electric machine and a second electric machine, has a motor vehicle transmission according to one or more of the variants described above. A rotor of the first electric machine is coupled to the first drive shaft of the motor vehicle transmission, while a rotor of the second electric machine is coupled to the second drive shaft. Within the scope of the invention, the respective electric machine can in particular be operated on the one hand as a generator and on the other hand as an electric motor. This makes it possible to create a drive unit which is suitable for use in a motor vehicle in the form of an electric or hybrid vehicle. The two electric machines can be dimensioned the same in terms of their power, although the second electric machine is preferably designed to have a smaller power output than the first electric machine.In this respect, the first electric motor is a main drive machine, while the second electric motor is designed more as an auxiliary drive machine.

[0051] Particularly preferably, the first electric machine is arranged coaxially with the first drive shaft, and the rotor of the first electric machine is connected to the first drive shaft in a rotationally fixed manner. As a result, the first drive shaft and the rotor of the first electric machine run at the same speed during operation. Alternatively, it is also conceivable for the rotor of the first electric machine to be coupled to the first drive shaft via at least one gear ratio.

[0052] Alternatively, but preferably in addition, in a drive unit according to the invention, the second electric machine is arranged, in particular, coaxially with the second drive shaft of the motor vehicle transmission, wherein the rotor of the second electric machine is connected in a rotationally fixed manner to the second drive shaft. Accordingly, the rotor of the second electric machine and the second drive shaft of the motor vehicle transmission have the same rotational speed during operation. Alternatively, the rotor of the second electric machine and the second drive shaft could also be coupled to one another via at least one intermediate gear ratio.

[0053] In the case of an aforementioned drive unit, switching can be carried out under load in the motor vehicle transmission between a state in which the gear is engaged between the two drive shafts and the output shaft in the motor vehicle transmission, and a state in which superposition operation is represented in the motor vehicle transmission. To this end, on the one hand, switching takes place between the second switching element and the third switching element, and for this purpose, speed synchronization is carried out on the third switching element and on the second switching element via the second electric machine, and a tractive force is supported via the first electric machine. On the other hand, switching takes place between an actuated and a deactuated state of the first switching element, and for this purpose, a load-free state is brought about on the first switching element through the interaction of the two electric machines.Depending on whether switching from the gear to the superposition mode or vice versa from the superposition mode to the gear, the step of switching between the second switching element and the third switching element takes place upstream or downstream of the step of changing between the actuated and the unactuated state of the first switching element.

[0054] In a further development of the invention, switching under load takes place between the state in which superposition operation is represented in the motor vehicle transmission and a state in which the further gear is engaged between the two drive shafts and the output shaft in the motor vehicle transmission, by firstly switching between the second switching element and the third switching element and, for this purpose, a speed synchronization is carried out on the third switching element and on the second switching element via the second electric machine, and a tractive force is supported via the first electric machine. Secondly, switching is carried out between an actuated and a deactuated state of the further switching element and, for this purpose, a load-free state is brought about on the further switching element through the interaction of the two electric machines.Here, too, the temporal sequence of these steps depends on whether the transition is from superimposed operation to the next gear or from the next gear to superimposed operation. Furthermore, this further development can preferably take place prior to a switch between the gear and superimposed operation, in order to be able to switch between the gear and the next gear via the intermediate superimposed operation under load.

[0055] Alternatively or in addition to the aforementioned development, switching under load takes place between the state in which superposition operation is represented in the motor vehicle transmission and a state in which the additional gear is engaged between both drive shafts and the output shaft by switching between an actuated and a deactuated state of the additional shifting element and, for this purpose, a load-free state is brought about on the additional shifting element through the interaction of the two electric machines. In addition, switching can be carried out between the second shifting element and the third shifting element, and for this purpose, speed synchronization can be carried out on the third shifting element and on the second shifting element via the second electric machine, and a tractive force can be supported via the first electric machine.The temporal sequence of these steps depends on whether the transition is from superimposed operation to the additional gear or from the additional gear to superimposed operation. Furthermore, this further development can take place, in particular, after a switch between the gear and superimposed operation, in order to be able to switch between the gear and the additional gear via the intermediate superimposed operation under load.

[0056] A drive unit designed according to one or more of the aforementioned variants is, in particular, part of a motor vehicle drive axle, which is provided for an electric or hybrid vehicle. The drive unit is preferably arranged in a plane with output shafts, each of which is assigned to at least one drive wheel and is coupled to the output shaft of the motor vehicle transmission. This advantageously allows a compact design of a motor vehicle drive axle with the drive unit to be achieved, wherein the coupling between the output shaft of the motor vehicle transmission and the output shafts of the motor vehicle drive axle is implemented, in particular, via a differential gear set.

[0057] Within the scope of the invention, at least one such motor vehicle drive axle is provided in a hybrid or electric vehicle, which may be a passenger car or a commercial vehicle. A commercial vehicle may be an at least partially electrically powered van or a light to medium-duty bus or truck.

[0058] Advantageous embodiments of the invention, which are explained below, are illustrated in the drawings. It shows: Fig. 1 is a schematic view of a drive unit according to an embodiment of the invention; Fig. 2 a tabular representation of different functions of the drive unit Fig. 1; Fig. 3 and Fig. 4 each shows a schematic representation of a drive unit corresponding to a further possible embodiment of the invention; Fig. 5 a tabular representation of different functions of the drive units from the Fig. 3 and Fig. 4; Fig. 6 is a schematic view of a drive unit according to another embodiment of the invention; Fig. 7 a tabular representation of different functions of the drive unit Fig. 6; Fig. 8 shows a schematic representation of a drive unit according to a further embodiment of the invention; Fig. 9 a tabular representation of different functions of the drive unit from Fig. 8; and Fig. 10 is a schematic view of an electric vehicle according to a preferred embodiment of the invention.

[0059] Out of Fig. Figure 1 shows a schematic view of a drive unit 1 designed according to an embodiment of the invention. This drive unit 1 is composed of a motor vehicle transmission 2 and two electric machines 3 and 4, wherein the motor vehicle transmission 2 is designed according to a first embodiment of the invention. The two electric machines 3 and 4 are each formed in a manner known in principle to those skilled in the art by a stator 5 and 6, respectively, and a rotor 7 and 8, respectively, wherein the individual electric machine 3 and 4 can be operated either as a generator or as an electric motor.

[0060] The motor vehicle transmission 2 comprises a first input shaft 9, a second input shaft 10, an output shaft 11, and two planetary gear sets P1 and P2, each composed of a first element E11 or E12, a second element E21 or E22, and a third element E31 or E32. The respective first element E11 or E12 of the respective planetary gear set P1 or P2 is a respective sun gear 12 or 13, while the respective second element E21 or E22 of the respective planetary gear set P1 or P2 is designed as a respective planet carrier 14 or 15. Furthermore, the respective third element E31 or E32 of the respective planetary gear set P1 or P2 is present as a respective ring gear 16 or 17 of the respective planetary gear set P1 or P2.

[0061] At least one planetary gear 18 or 19 is rotatably mounted in the respective planetary carrier 14 or 15 of the respective planetary gear set P1 or P2, respectively, which meshes with both the respective sun gear 12 or 13 and the respective ring gear 16 or 17 of the respective planetary gear set P1 or P2. In this respect, the planetary gear sets P1 and P2 are designed as negative planetary gear sets.

[0062] In the present case, both the first element E11 of the first planetary gear set P1 and the first element E12 of the second planetary gear set P2 are each connected in a rotationally fixed manner to the first drive shaft 9, which is also connected in a rotationally fixed manner to the rotor 7 of the electric machine 3 at a connection point 20. In this respect, the first element E11 of the first planetary gear set P1, the first element E12 of the second planetary gear set P2, and the rotor 7 are also connected in a rotationally fixed manner to one another via the first drive shaft 9, whereby the first element E11 of the first planetary gear set P1, the first element E12 of the second planetary gear set P2, and the rotor 9 always rotate at the same speed. Within the scope of the invention, the first drive shaft 9 can be formed integrally with the first element E11 of the first planetary gear set P1 and / or with the first element E12 of the second planetary gear set P2 and / or with the rotor 7 of the electric machine 3.

[0063] The output shaft 11 is rotationally fixedly connected to the second element E22 of the second planetary gear set P2. The output shaft 11 further has a connection point 21, at which the output shaft 11 is preferably coupled to a downstream differential gear. Furthermore, the second element E21 of the first planetary gear set P1 and the third element E32 of the second planetary gear set P2 are rotationally fixedly connected to one another via a shaft 22. The shaft 22 could optionally be configured as a single piece with the second element E21 of the first planetary gear set P1 and / or with the third element E32 of the second planetary gear set P2.

[0064] The third element E31 of the first planetary gear set P1 is permanently connected in a rotationally fixed manner to a shaft 23, so that the shaft 23 and the third element E31 of the first planetary gear set P1 always rotate at the same speed. In this case, the third element E31 of the first planetary gear set P1 could also be designed as a single piece with the shaft 23. Furthermore, the second drive shaft 10 is connected in a rotationally fixed manner to the rotor 8 of the electric machine 4, so that the second drive shaft 10 and the rotor 8 always run at the same speed. The rotationally fixed connection is established at a connection point 24 of the second drive shaft 10, whereby the second drive shaft 10 and the rotor 8 of the electric machine 4 can also be designed as a single piece within the scope of the invention.

[0065] The motor vehicle transmission 3 also has two shifting devices 25 and 26. The shifting device 25 has a coupling element 27 in the form of a sliding sleeve, which is guided in a rotationally fixed and axially displaceable manner on a toothing 28 that is rotationally fixedly connected to a component 29 fixed to the housing. The component 29 fixed to the housing is a transmission housing of the motor vehicle transmission 2, a part of the transmission housing, or a component connected thereto in a rotationally fixed manner. In this transmission housing of the motor vehicle transmission 2, in addition to components of the motor vehicle transmission 2, the two electric motors 3 and 4 are preferably also accommodated. Due to the rotationally fixed connection to the component 29 fixed to the housing, the toothing 28 is also permanently stationary.Axial displacements of the coupling element 27 on the toothing 28 can be carried out via an actuating actuator - not shown further here - which is preferably designed as an electromechanical actuating actuator.

[0066] The coupling element 27 can be axially transferred into two different switching states via the actuating actuator under constant guidance on the toothing 28, wherein in each of the switching states, a tooth engagement of the coupling element 27 is effected with a respective associated toothing 30 or 31. The toothing 30 is formed on the shaft 22 and is thus connected in a rotationally fixed manner to the second element E21 of the first planetary gear set P1 and the third element E32 of the second planetary gear set P2, while the toothing 31 is provided in a rotationally fixed manner on the shaft 23 and is accordingly also connected in a rotationally fixed manner to the third element E31 of the first planetary gear set P1.

[0067] The switching device 25 thereby maps the function of two switching elements A and B, whose respective actuated state is represented by the switching device 25 in each of the switching states of the coupling element 27. Thus, an actuated state of the switching element A is realized in a first switching state of the coupling element 27, in which the coupling element 28, while meshing with the toothing 28, additionally engages the toothing 30. This results in a rotationally fixed connection of the shaft 22 to the housing-fixed component 29 and thus a locking of the shaft 22 together with the second element E21 of the first planetary gear set P1 and the third element E32 of the second planetary gear set P2.

[0068] From the first switching state, the coupling element 27 can be transferred via the actuator into a neutral state, which Fig. 1, in which the coupling element 27 is only in meshing engagement with the toothing 28. As a result, no coupling is established via the switching device 25 in this neutral state.

[0069] In addition to transferring the coupling element 27 to the first switching state, the coupling element 28 can also be moved from the neutral state to a second switching state, in which the coupling element 28, while already meshing with the toothing 28, is also meshed with the toothing 31. As a result, the coupling element 27 connects the shaft 23 in a rotationally fixed manner to the housing-fixed component 29, which results in the shaft 23 and thus also the third element E31 of the first planetary gear set P1 becoming locked. In the second switching state, an actuated state of the switching element B is represented.

[0070] The switching device 26 also has a coupling element 32 in the form of a sliding sleeve, wherein the coupling element 32 is guided in a rotationally fixed and axially displaceable manner on a toothing 33 which is formed on the second drive shaft 10. From a Fig. 1, in which the coupling element 32 does not perform any coupling, the coupling element 32 can be transferred axially into a first switching state via an associated actuating actuator (not shown here).

[0071] In this first switching state, the coupling element 32, while meshing with the toothing 33, engages with a toothing 34 formed on the shaft 23. This results in a rotationally fixed connection of the second drive shaft 10 to the shaft 23 in the first switching state of the coupling element 32, whereby the third element E31 of the first planetary gear set P1 is also rotationally fixedly connected to the second drive shaft 10. In the first switching state, an actuated state of a switching element D is represented.

[0072] On the other hand, the coupling element 32 can also be transferred axially from the neutral state via the associated actuating actuator into a second switching state, in which the coupling element 32, while still meshing with the toothing 33, additionally engages with a toothing 35. This toothing 35 is formed on the first drive shaft 9, so that in the second switching state of the coupling element 32, a rotationally fixed connection of the two drive shafts 9 and 10 is achieved. This represents an actuated state of a switching element E. In this respect, the switching device 26 implements the functions of the two switching elements D and E.

[0073] As in Fig. As can be seen in Figure 1, the first drive shaft 9, the second drive shaft 10, the output shaft 11, and also the planetary gear sets P1 and P2 are arranged coaxially with one another, with the two electric motors 3 and 4 also being positioned coaxially with the shafts 22 and 23. Axially following the electric motor 3 is the electric motor 4, then the first planetary gear set P1, then the second planetary gear set P2, and finally the connection point 21 of the output shaft 11.

[0074] The switching device 25 is provided so as to axially overlap the second planetary gear set P2 and is located radially surrounding the two planetary gear sets P1 and P2, while the switching device 26 is placed so as to axially overlap the electric machine 4. The switching device 26 is located axially between the connection point 24 and the first planetary gear set P1, wherein the switching device 26, together with the two planetary gear sets P1 and P2 and the switching device 25, is placed radially inward of the two electric machines 3 and 4. While the first drive shaft 9 and the output shaft 11 are essentially designed as solid shafts, which are arranged coaxially and axially next to one another, the second drive shaft 10 and also the shafts 23 and 24 are hollow shafts.

[0075] Fig. 2 shows a tabular overview of different states I to VIII, which are generated via the drive unit 1 from Fig. 1. In states I, II, and VI, a first gear G1 is engaged in the motor vehicle transmission 2 of the drive unit 1, for which purpose the coupling element 27 of the shifting device 25 is moved into its first shift position (actuated state A). This fixes the shaft 22, so that the first drive shaft 9 is coupled to the output shaft 11 via the second planetary gear set P2.

[0076] In state I, the coupling element 32 of the switching device 26 is also transferred to its second switching position (actuated state E), so that the second drive shaft 10 is also connected in a rotationally fixed manner to the first drive shaft 9. As a result, in state I, both electric motors 3 and 4 are integrated in first gear G1, allowing a common drive via the electric motors 3 and 4.

[0077] In contrast, in state II, in addition to positioning the coupling element 27 of the switching device 25 in the first switching position (actuated state A), the coupling element 32 of the switching device 26 is placed in the second switching position (actuated state D), whereby the second drive shaft 10 is connected in a rotationally fixed manner to the shaft 23. As a result, the second drive shaft 10 and thus also the electric machine 4 are coupled to the first drive shaft 9 via the first planetary gear set P1, wherein the second drive shaft 10 is then coupled to the output shaft 11 in an intermediate gear ZG via the first planetary gear set P1 and the second planetary gear set P2.

[0078] In state VI, however, only the first input shaft 9 is coupled to the output shaft 11, and thus only the electric motor 3 is connected, while the electric motor 4 is decoupled. To do this, the neutral position of the coupling element 32 of the switching device 26 must be set, while the coupling element 27 of the switching device 25 is positioned in the first switching position (actuated state A). This allows drag losses of the electric motor 4 to be avoided.

[0079] A second gear G2 is engaged in the motor vehicle transmission of the drive unit 1 by moving the coupling element 27 of the shifting device 25 into its second shift position (actuated state B). This occurs in states IV, V, and VII, respectively. In the second shift position of the coupling element 27, the shaft 23 is then locked, resulting in a coupling of the first drive shaft 9 to the output shaft 11 via both planetary gear sets P1 and P2.

[0080] In state IV, the coupling element 32 of the switching device 26 is also transferred to its first switching position (actuated state D), whereby the second drive shaft 10 is connected in a rotationally fixed manner to the shaft 23. This shaft is fixed when the actuated state of the switching element B is shown, so that the rotor 8 of the electric motor 4 is also fixed. The electric motor 4 can be used to support traction during switching in the switching device 25 and also to synchronize the switching device 25.

[0081] In state V, however, the switching device 26 additionally moves the coupling element 32 into its first switching position (actuated state E), so that the two drive shafts 9 and 10 are again connected to each other in a rotationally fixed manner. As a result, both drive shafts 9 and 10 are then coupled to the output shaft 11 in second gear G2, whereby both electric motors 3 and 4 are also integrated in second gear G2.

[0082] Furthermore, only the first drive shaft 9 and thus the electric motor 3 alone can be engaged in second gear G2 (state VII). For this purpose, when the coupling element 27 of the switching device 25 is placed in its second switching position (actuated state B), the neutral position of the coupling element 32 must be reset on the switching device 26. As a result, the electric motor 4 is decoupled, which can reduce drag losses.

[0083] In state III, drive movements of electric motors 3 and 4 can be superimposed in a superposition mode EDF. For this purpose, the coupling element 32 of the switching device 26 must be placed in its second switching position (actuated state D), while the coupling element 27 of the switching device 25 is in its neutral position. As a result, the second drive shaft 10 is connected in a rotationally fixed manner to the shaft 23 and thus to the third element E31 of the first planetary gear set P2. This results in a speed superposition of the electric motors 3 and 4 via the two planetary gear sets P1 and P2 on the output shaft 11.

[0084] In the superposition mode EDF, driving operation can also be realized via the two electric motors 3 and 4. For example, the two electric motors 3 and 4 can have the same speed, which results in a blocking of the two planetary gear sets P1 and P2 and thus a rigid through-drive from both drive shafts 9 and 10 to the output shaft 11.

[0085] In state VIII, however, both drive shafts 9 and 10 are decoupled from the output shaft 11 by setting the neutral position of the coupling element 27 in the switching device 25 and transferring the coupling element 32 to its second switching position (actuated state E) in the switching device 26. Although the two drive shafts 9 and 10 are thus connected to each other in a rotationally fixed manner, there is no coupling with the output shaft 11 due to the free rotation of the shaft 23.

[0086] By appropriately sequencing states I to VII, a power shift between the first gear G1 and the second gear G2 can be realized in the drive unit 1 in the motor vehicle transmission 2: initially, within the scope of state I, both electric machines 3 and 4 are integrated in the first gear G1. Subsequently, the switching device 26 then transfers the coupling element 32 from the second switching position (actuated state E) to the first switching position (actuated state D), wherein during the switching, speed synchronization is carried out at the second switching device 26 via the second electric machine 4 and traction support is carried out via the electric machine 3 in the first gear G1. This realizes state II, in which the electric machine 4 is coupled to the output shaft 11 with a fixed speed ratio. This could also be used as a driving state for an extended period of time.

[0087] Next, a load-free state of the coupling element 27 is set on the switching device 25 by adjusting a suitable torque ratio between the electric motors 3 and 4, and the coupling element 27 is then transferred to its neutral position, thereby implementing state III. Within the scope of this state III, the tractive force is also supported in the superimposed EDF mode. Extended driving operation could also be achieved in the superimposed EDF mode.

[0088] Subsequently, the coupling element 27 is transferred to its second switching position (actuated state B), whereby a speed synchronization is carried out on the switching device 25 by appropriately adjusting the speed of the electric motor 3. Once the switching is complete, the second gear G2 is engaged between the first drive shaft 9 and the output shaft 11, whereby the second drive shaft 10 and thus also the electric motor 4 are braked and state IV is realized.

[0089] To finally engage the second gear G2 between both drive shafts 9 and 10 and the output shaft 11, the shifting device 26 then shifts again, with the electric motor 3 again supporting the traction force. To shift, the speed is synchronized via the electric motor 4 at the shifting device 26. Once the shifting is complete, state V is reached, thus connecting both electric motors 3 and 4 to the second gear G2.

[0090] A downshift under load from the second gear G2 to the first gear G1 can then be carried out in a mirror image of what has been described above.

[0091] Furthermore, Fig. 3 shows a schematic representation of a drive unit 36, which is designed according to a further embodiment of the invention. This drive unit 36 ​​largely corresponds to the variant according to Fig. 1, with the difference that in a motor vehicle transmission 37 of the drive unit 36, a switching device 38 is provided, which in addition to the functions of the switching elements A and B also additionally represents the function of a switching element C. The switching device 38 has a coupling element 39, which can be moved axially via a - here not shown - actuating actuator of the switching device 38. In a first, in Fig. 3, the coupling element 39 represents an actuated state of the switching element A and is in meshing engagement with the toothing 28 on the one hand and with the toothing 30 on the other hand. In an analogous manner to the variant according to Fig. 1, the shaft 22 is then connected in a rotationally fixed manner to the permanently fixed component 29 and is accordingly fixed itself.

[0092] From the first switching state, the coupling element 39 of the switching device 38 can be transferred into a first neutral state, in which the coupling element 39 is only in meshing engagement with the toothing 28. As a result, no coupling is then established via the coupling element 39. In addition to a return to the first switching state, the coupling element 39 can then be moved axially from the first neutral state under rotationally fixed guidance on the toothing 28 into a second switching state, in which the coupling element 39, while still in meshing engagement with the toothing 28, additionally engages the toothing 31. This represents the actuated state of the switching element B and is analogous to the variant according to Fig. 1 causes the shaft 23 to become stuck.

[0093] On the one hand, the coupling element 39 can be transferred back from the second switching state to the first neutral state, whereby the coupling element 39 can, however, be moved into a second neutral state by an axial displacement in the opposite axial direction. This movement takes place under rotationally fixed, axially displaceable guidance on the toothing 31, whereby in the second neutral state there is only a tooth engagement with the toothing 31 and thus no coupling is established via the coupling element 39. From the second neutral state, the coupling element 39 can then, on the one hand, be transferred into the second switching state, whereby, alternatively, an axial displacement of the coupling element 39 into a third switching state is also possible, in which the coupling element 39, while still engaging with the toothing 31, also engages with the toothing 30.As a result, the coupling element 39 connects the shaft 22 to the shaft 23 in a rotationally fixed manner, which results in a common blocking of the two planetary gear sets P1 and P2 and represents an actuated state of the switching element C. Otherwise, the embodiment according to . Fig. 3 of the variant Fig. 1, so that reference is made to what has been described in this regard.

[0094] Furthermore, Fig. 4 shows a schematic view of a drive unit 40, wherein this drive unit 40 is designed according to a further embodiment of the invention. The drive unit 40 essentially corresponds to the drive unit 36 ​​of Fig. 3, wherein the drive unit 40 is located from the drive unit 36 Fig. 3 in that a third planetary gear set P3 is now additionally provided in a motor vehicle transmission 41 of the drive unit 40. The third planetary gear set P3 has a first element E13, a second element E23 and a third element E33, wherein the first element E13 is a sun gear 42 of the third planetary gear set P3, the second element E23 is a planet carrier 43 of the third planetary gear set P3 and the third element E33 is a ring gear 44 of the third planetary gear set P3. A plurality of planet gears 45 are each rotatably mounted in the planet carrier 43, wherein each planet gear 45 is in meshing engagement with both the sun gear 42 and the ring gear 44. In this respect, the third planetary gear set P3 is also designed as a minus planetary set.

[0095] The third planetary gear set P3 is arranged axially on a side of the second planetary gear set P2 facing away from the first planetary gear set P1 and is located at the level of the connection point 21 of the output shaft 11. The output shaft 11 is connected at its connection point 21 in a rotationally fixed manner to the first element E13 of the third planetary gear set P3, while the third element E33 of the third planetary gear set P3 is connected in a rotationally fixed manner to the housing-fixed component 29 and is thus permanently fixed. Finally, the second element E23 of the third planetary gear set P3 is connected in a rotationally fixed manner to an output shaft 47, which is arranged coaxially to the output shaft 11 and on its end face. The output shaft 46 then further establishes the coupling to the downstream differential gear set. The planetary gear set P3 realizes a constant gear ratio from the output shaft 11 to the output shaft 46.Otherwise, the design options correspond to . Fig. 4 of the variant Fig. 3, so that reference is made to what has been described in this regard.

[0096] Out of Fig. 5 also shows a tabular overview of different states I' to XI', which are generated via the drive units 36 and 40 from the Fig. 3 and Fig. 4 can be represented. The states I' to XI' correspond in their realization and mode of action to the states I to VIII according to Fig. 2.

[0097] Thus, state I' is identical to state I according to Fig. 2, State II' identical to State II' from Fig. 2, State III' identical to State III according to Fig. 2, State IV' identical to State IV from Fig. 2, state V' identical to state V from Fig. 2, Condition VIII' identical to Condition VI according to Fig. 2, state IX' identical to state VII from Fig. 2 and condition XI' identical to condition VIII according to Fig. 2, so that in each case the relevant Fig. 2. In addition, a power shift between the first gear G1 and the second gear G2 can be carried out analogously to the Fig. 2 described above.

[0098] In addition, in the motor vehicle transmissions 37 and 41 of the drive units 36 and 40, a third gear G3 can be engaged by moving the coupling element 39 of the switching device 38 into its third switching position (actuated state C). This is done in the states VI', VII', and X', respectively. In the third switching position, the two planetary gear sets P1 and P2 are then blocked, so that the drive shaft 9 is connected in a rotationally fixed manner to the output shaft 11, thus enabling a rigid drive from the electric motor 3 to the output shaft 11.

[0099] In state VI', the coupling element 32 of the switching device 26 is also transferred to its second switching position (actuated state E), so that the second drive shaft 10 is also connected in a rotationally fixed manner to the first drive shaft 9. As a result, in state VI', both electric motors 3 and 4 are then integrated in the third gear G3, allowing a joint drive via the electric motors 3 and 4.

[0100] In contrast, in state VII', in addition to positioning the coupling element 39 of the switching device 38 in the third switching position (actuated state C), the coupling element 32 of the switching device 26 is placed in the first switching position (actuated state D), whereby the second drive shaft 10 is connected in a rotationally fixed manner to the shaft 23. As a result, the second drive shaft 10 and thus also the electric motor 4 are connected in a rotationally fixed manner to the output shaft 11 and also to the first drive shaft 9 via the interlocked planetary gear sets P1 and P2, so that the third gear G3 is also engaged between the two drive shafts 9 and 10 and the output shaft 11.

[0101] In state X', however, only the first input shaft 9 is coupled to the output shaft 11, and thus only the electric motor 3 is engaged in third gear G3, while the electric motor 4 is decoupled. For this purpose, the neutral position of the coupling element 32 of the switching device 26 must be set, while the coupling element 39 of the switching device 38 is positioned in the third switching position (actuated state C). This allows drag losses of the electric motor 4 to be avoided.

[0102] In the case of the drive units 36 and 40, a shift from the second gear G2 to the third gear G3 under load can also be represented. The initial state is state V', in which both electric motors 3 and 4 are integrated in the second gear G2. First, in the respective motor vehicle transmission 37 or 41, the shifting device 26 then switches from the second switching state of the coupling element 32 (actuated state E) to the first switching state of the coupling element 32 (actuated state D), in the course of which the tractive force is supported via the electric motor 3 in the second gear G2. Once the switch has been completed, state IV' is reached, in which the electric motor 4 is at a standstill.

[0103] Subsequently, by setting a suitable torque ratio of electric motors 3 and 4 in the switching device 38, the coupling element 39 is de-energized and then transferred from the second switching state (actuated state B) to its second neutral state. This then sets the superposition operation to state III'.

[0104] Subsequently, the electric machine 3 is brought to the same speed as the electric machine 4, whereby the two planetary gear sets P1 and P2 are in block circulation. This also results in speed synchronization with respect to the third gear G3 on the switching device 38, so that the coupling element 39 can now be moved into its third switching position (actuated state C) and, subsequently, upon reaching state VII', the third gear G3 is engaged between the input shaft 9 and the output shaft 11. In addition, the switching device 26 can also transition from the first switching state (actuated state D) to the second switching state (actuated state E), whereby state VI' is then reached.

[0105] A downshift from the third gear G3 can be carried out in a mirror image to the second gear G2, but a downshift can also be carried out with interruption of the tractive force by switching from the third switching state (actuated state C) to the second switching state (actuated state B) with speed synchronization when the coupling element 32 is positioned in its second switching state (actuated state E) on the part of the switching device 38.

[0106] Furthermore, Fig. 6 shows a schematic view of a drive unit 47 according to a further embodiment of the invention. This embodiment largely corresponds to the variant according to Fig. 1, wherein in a motor vehicle transmission 48 of the drive unit 47, in contrast to the variant according to Fig. 1, the shift elements D and E are now designed as individual shift elements. In this case, the shift elements D and E are each in the form of positive-locking shift elements in the form of claw shift elements. For shift element D, a coupling element 49 is provided, which is guided in a rotationally fixed and axially displaceable manner on a toothing 50 that is formed on the second drive shaft 10. To actuate the shift element D, the coupling element 49 can be moved axially into a switching position via an actuating actuator (not shown in detail here), in which the coupling element 49, while meshing with the toothing 50, additionally engages the toothing 34 formed on the shaft 23. Accordingly, in the motor vehicle transmission 48, a rotationally fixed connection between the drive shaft 10 and the shaft 23 is also brought about in the actuated state of the shift element D.

[0107] The switching element E has a coupling element 51, which is guided in a rotationally fixed and axially displaceable manner on a toothing 52, which is also formed on the second drive shaft 10. From a Fig. 6, which defines an unactuated state of the switching element E, the coupling element 51 can be axially transferred into a switching position in which the coupling element 51, while meshing with the toothing 52, also engages with the toothing 35. This then results in a rotationally fixed connection of the drive shaft 10 to the drive shaft 9.

[0108] While the switching element D is provided axially between the connection point 24 of the drive shaft 10 and the first planetary gear set P1, the switching element E is located axially between the connection point 24 of the drive shaft 10 and the connection point 20 of the drive shaft 9. Otherwise, the embodiment according to Fig. 6 otherwise according to the variant Fig. 1, so that reference is made to what has been described in this regard.

[0109] In addition, Fig. 7 a tabular overview of different states I'' to IX'' of the drive unit 47 from Fig. 6. The states I'' to V'' essentially correspond to the states I' to V' according to Fig. 5, each with the only difference that the switching device 25 realizes the actuated states A and B and a respective actuated state D or E is represented directly by the respective individual switching element D or E.

[0110] In a state VI'' of the drive unit 47 from Fig. 3, a third gear G3 is also engaged in the motor vehicle transmission 48 between the two drive shafts 9 and 10 and the output shaft 11, for which purpose the individual shifting elements D and E are actuated simultaneously. In this case, the second gear G2 (state V'') engaged between the two drive shafts 9 and 10 and the output shaft 11 can be shifted into the third gear G3 under load by opening the shifting element E and subsequently actuating the shifting element D, during which the tractive force is supported via the electric machine 3 in the second gear G2. Once the shift has been completed, state IV'' is reached, in which the electric machine 4 is at a standstill.

[0111] Next, by setting a suitable torque ratio of electric motors 3 and 4, the coupling element 27 is de-energized in the switching device 25 and then transferred from the second switching state (actuated state B) to its second neutral state. This establishes state III'' and thereby sets the superposition mode EDF.

[0112] Subsequently, electric motor 3 is brought to the same speed as electric motor 4, causing the two planetary gear sets P1 and P2 to rotate in block fashion. Upon reaching block fashion of the two planetary gear sets P1 and P2, switching element E and switching element D are additionally actuated, thus realizing state VI''.

[0113] Finally, states VII'', VIII' and IX'' can also be represented for the drive unit 47. In state VII'', only the first input shaft 9 is coupled to the output shaft 11, representing the first gear G1, in that the coupling element 27 in the switching device 25 is positioned in the first switching position (actuated state A). When state VIII'' is realized, the first input shaft is also coupled to the output shaft 11, whereby this is done in the second gear G2. For this purpose, the coupling element 27 in the switching device 25 must be transferred to its second switching position (actuated state B). This makes it possible to avoid drag losses of the electric machine. Finally, when state IX'' is represented, both input shafts 9 and 10 are decoupled from the output shaft 11, in that only the switching element E is actuated.

[0114] In addition, Fig. 8 shows a schematic representation of a drive unit 53, which is designed according to a further embodiment of the invention. The drive unit 53 largely corresponds to the drive unit 36 ​​of Fig. 3, with the difference that in a motor vehicle transmission 54 of the drive unit 53, only the functions of the switching elements B and C are now represented by a switching device 55. The switching device 55 has a coupling element 56, which is guided on the toothing 31 and thus on the shaft 23 in a rotationally fixed and axially displaceable manner, wherein the coupling element 56 can be moved axially via an actuating actuator - not shown in detail here. Fig. In the neutral position shown in Figure 8, the coupling element 56 can be transferred into a first switching position, in which the coupling element 56, while meshing with the toothing 31, also engages the toothing 28, which is non-rotatably connected to the housing-fixed component 29. This results in the shaft 23 becoming jammed and represents the actuated state of the switching element B.

[0115] On the other hand, the coupling element 56 can be moved from a neutral position in an opposite axial direction into a second switching position, in which the coupling element 56, while still meshing with the toothing 31, additionally engages the toothing 30. The toothing 30 is again formed on the shaft 22, so that in the second switching position of the coupling element 56, a rotationally fixed connection of the shafts 22 and 23 is achieved. This represents the actuated state of the switching element C. The switching device 55 is provided axially overlapping with and radially surrounding the first planetary gear set P1. Otherwise, the embodiment according to Fig. 8 of the variant Fig. 3, so that reference is made to what has been described in this regard.

[0116] In Fig. 9 are different states I''' to VII''' of the drive unit 53 from Fig. 8. The state I''' essentially corresponds to the state V' from Fig. 5, the state II''' essentially the state IX' from Fig. 5, the state III''' the state III' from Fig. 5 , the state IV''' the state X' from Fig. 5, the state V''' the state IX' from Fig. 5, the state VI''' the state VII' from Fig. 5 and state VII''' state VI' from Fig. 5, in each case with the only difference that the switching device 55 now realizes the actuated states B and C. In this respect, reference is made to the respective Fig. 5. A power shift between the second gear G2 and the third gear G3 can also be carried out analogously to the Fig. 5 described above.

[0117] Finally, Fig.10 is a schematic view of an electric vehicle 57. In addition to a steerable, non-driven vehicle axle 58, the electric vehicle 57 also has a motor vehicle drive axle 59 with drive wheels 60 and 61. The drive wheels 60 and 61 are coupled via a differential gear 62 to a drive unit 63, which corresponds to one of the drive units 1, 36, 40, 47 and 53.

[0118] While the vehicle axle 58 is a front axle of the electric vehicle 57, the motor vehicle drive axle 59 is a rear axle of the electric vehicle 57. However, alternatively or in addition to the motor vehicle drive axle 59, the vehicle axle 58 could also be designed as a driven axle with, if appropriate, an analogous structure of a drive unit.

[0119] By means of the embodiments according to the invention, a compact motor vehicle transmission can be created with which a suitable integration of two drive machines is possible. Reference symbol 1 drive unit 2 motor vehicle transmissions 3 Electric machine 4 Electric machine 5 Stator 6 Stator 7 Rotor 8 Rotor 9 Drive shaft 10 Drive shaft 11 Output shaft 12 Sun gear 13 Sun gear 14 planet carriers 15 planet carriers 16 ring gear 17 Ring gear 18 Planetary gear 19 Planetary gear 20 Junction 21 Junction 22 Wave 23 Wave 24 Junction 25 Switching device 26 Switching device 27 Coupling element 28 Gearing 29 housing-fixed component 30 Gearing 31 Gearing 32 coupling element 33 Gearing 34 Gearing 35 Gearing 36 drive unit 37 automotive transmissions 38 Switching device 39 coupling element 40 drive unit 41 Automotive transmissions 42 Sun gear 43 planet carrier 44 ring gear 45 Planetary gear 46 Output shaft 47 Drive unit 48 automotive transmissions 49 coupling element 50 gearing 51 coupling element 52 Gearing 53 Drive unit 54 automotive transmissions 55 Switching device 56 coupling element 57 electric vehicles 58 vehicle axle 59 Motor vehicle drive axle 60 drive wheel 61 Drive wheel 62 differential gears 63 Drive unit P1 First planetary gear set P2 Second planetary gear set P3 Third planetary gear set E11 First element of the first planetary gear set E21 Second element of the first planetary gear set E31 Third element first planetary gear set E12 First element of the second planetary gear set E22 Second element of second planetary gear set E32 Third element second planetary gear set E13 First element of the third planetary gear set E23 Second element of the third planetary gear set E33 Third element third planetary gear set A switching element B switching element C switching element D switching element E switching element G1 Gang G2 Gear G3 Gear ZG intermediate course EDF overlay operation I to VIII states I' to XI' states I'' to IX'' states I''' to VII''' states QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] US 4,702,125 A

[0003]

Claims

[1] Motor vehicle transmission (2; 37; 41; 48; 54) for an at least partially electrically driven motor vehicle, comprising a first drive shaft (9), an output shaft (11) and a first planetary gear set (P1) and a second planetary gear set (P2), - wherein the first drive shaft (9) is provided for coupling to a first drive machine, in particular a first electric machine (3), - wherein the first planetary gear set (P1) and the second planetary gear set (P2) each have a first element (E11, E12), a second element (E21, E22) and a third element (E31, E32) in the form of a sun gear (12, 13), a planet carrier (14, 15) and a ring gear (16, 17), - wherein at least functionally a first switching element (B), a second switching element (D) and a third switching element (E) are provided, - wherein the first element (E11) of the first planetary gear set (P1) and the first element (E12) of the second planetary gear set (P2) are connected in a rotationally fixed manner to the first drive shaft (9), - wherein the second element (E22) of the second planetary gear set (P2) is connected in a rotationally fixed manner to the output shaft (11), - wherein the second element (E21) of the first planetary gear set (P1) and the third element (E32) of the second planetary gear set (P2) are connected to one another in a rotationally fixed manner, - and wherein the at least functionally provided first switching element (B) is designed to fix the third element (E31) of the first planetary gear set (P1) in an actuated state, characterized by , - that a second drive shaft (10) is provided, which serves for coupling to a second drive machine, in particular a second electric machine (4), - that the at least functionally provided second switching element (D) is designed to connect the second drive shaft (10) in an actuated state in a rotationally fixed manner to the third element (E31) of the first planetary gear set (P1), - and that the at least functionally provided third switching element (E) is designed to connect the second drive shaft (10) in a rotationally fixed manner to the first drive shaft (9) in an actuated state. [2] Motor vehicle transmission (2; 37; 41; 48) according to claim 1, characterized by that in addition, at least functionally, a further switching element (A) is provided which is designed to fix the second element (E21) of the first planetary gear set (P1) and the third element (E32) of the second planetary gear set (P2) in an actuated state. [3] Motor vehicle transmission (2; 48) according to claim 2, characterized byin that the first shifting element (B) and the further shifting element (A) are formed by a common shifting device (25) which has a coupling element (27), wherein the coupling element (27) can be transferred into a first shifting state and into a second shifting state, wherein the coupling element (27) in its first shifting state functionally maps the actuated state of the first shifting element (B) and fixes the third element (E31) of the first planetary gear set (P1), and wherein the coupling element (27) in its second shifting state functionally maps the actuated state of the further shifting element (A) and fixes the second element (E21) of the first planetary gear set (P1) and the third element (E32) of the second planetary gear set (P2). [4] Motor vehicle transmission (2; 48) according to claim 3, characterized byin that the coupling element (27) is guided in a rotationally fixed and axially displaceable manner in each of its two switching states and during an axial displacement between its two switching states on a first toothing (28) which is fixed, wherein in the first switching state the coupling element (27) additionally engages with a second toothing (31) when there is tooth engagement with the first toothing (28) and which is connected in a rotationally fixed manner to the third element (E31) of the first planetary gear set (P1), and wherein in the second switching state the coupling element (27) additionally engages with a third toothing (30) when there is tooth engagement with the first toothing (28) and which is connected in a rotationally fixed manner to the second element (E21) of the first planetary gear set (P1) and the third element (E32) of the second planetary gear set (P2). [5] Motor vehicle transmission (37; 41; 54) according to one of the preceding claims, characterized bythat furthermore, at least functionally, an additional switching element (C) is provided which is designed, in an actuated state, to connect two of the elements (E11, E21, E31) of the first planetary gear set (P1) to one another in a rotationally fixed manner or to connect two of the elements (E12, E22, E32) of the second planetary gear set (P2) to one another in a rotationally fixed manner or to connect the third element (E31) of the first planetary gear set (P1) to the third element (E32) of the second planetary gear set (P2) in a rotationally fixed manner. [6] Motor vehicle transmission (37; 41) according to claim 2 and claim 5, characterized bythat the first switching element (B), the further switching element (A) and the additional switching element (C) are formed by a common switching device (38) which has a coupling element (39), wherein the coupling element (39) can be transferred into a first switching state, a second switching state and a third switching state, wherein the coupling element (39) in its first switching state functionally maps the actuated state of the further switching element (A) and fixes the second element (E21) of the first planetary gear set (P1) and the third element (E32) of the second planetary gear set (P2), wherein the coupling element (39) in its second switching state functionally maps the actuated state of the first switching element (B) and fixes the third element (E31) of the first planetary gear set (P1),and wherein the coupling element (39) in its third switching state functionally maps the actuated state of the additional switching element (C) and connects the second element (E21) of the first planetary gear set (P1) and the third element (E32) of the second planetary gear set (P2) in a rotationally fixed manner to the third element (E31) of the first planetary gear set (P1). [7] Motor vehicle transmission (37; 41) according to claim 6, characterized bythat the coupling element (39) in its first and second switching states and during an axial displacement between its first and second switching states is guided in a rotationally fixed and axially displaceable manner on a first toothing (28) which is fixed, wherein the coupling element (39) in its first switching state, when there is tooth engagement with the first toothing (28), additionally engages in a second toothing (30) which is connected in a rotationally fixed manner to the second element (E21) of the first planetary gear set (P1) and the third element (E32) of the second planetary gear set (P2), wherein the coupling element (39) in its second switching state, when there is tooth engagement with the first toothing (28), additionally engages in a third toothing (31) which is connected in a rotationally fixed manner to the third element (E31) of the first planetary gear set (P1),and wherein the coupling element (39) is guided in a rotationally fixed and axially displaceable manner on the third toothing (31) during an axial displacement between its second and its third switching state and, in its third switching state, additionally engages the second toothing (30) when the tooth engagement with the third toothing (31) is established. [8] Motor vehicle transmission (54) according to claim 5, characterized byin that the first shifting element (B) and the additional shifting element (C) are formed by a common shifting device (55) which has a coupling element (56), wherein the coupling element (56) can be transferred into a first shifting state and into a second shifting state, wherein the coupling element (56) in its first shifting state functionally maps the actuated state of the first shifting element (B) and fixes the third element (E31) of the first planetary gear set (P1), and wherein the coupling element (56) in its second shifting state functionally maps the actuated state of the additional shifting element (C) and connects the second element (E21) of the first planetary gear set (P1) and the third element (E32) of the second planetary gear set (P2) in a rotationally fixed manner to the third element (E31) of the first planetary gear set (P1). [9] Motor vehicle transmission (54) according to claim 8, characterized byin that the coupling element (56) is guided in a rotationally fixed and axially displaceable manner in each of the two switching states and during an axial displacement between its two switching states on a first toothing (31) which is rotationally fixedly connected to the third element (E31) of the first planetary gear set (P1), wherein the coupling element (56) in its first switching state, with existing tooth engagement with the first toothing (31), additionally engages in a second toothing (28) which is fixed, and wherein the coupling element (56) in its second switching state, with existing tooth engagement with the first toothing (31), additionally engages in a third toothing (30) which is rotationally fixedly connected to the second element (E21) of the first planetary gear set (P1) and the third element (E32) of the second planetary gear set (P2). [10] Motor vehicle transmission (2; 37; 41; 54) according to one of the preceding claims, characterized byin that the second shifting element (D) and the third shifting element (E) are formed by a common shifting device (26) which has a coupling element (32), wherein the coupling element (32) can be transferred into a first shifting state and into a second shifting state, wherein the coupling element (32) in its first shifting state functionally maps the actuated state of the second shifting element (D) and connects the second drive shaft (10) in a rotationally fixed manner to the third element (E31) of the first planetary gear set (P1), and wherein the coupling element (32) in its second shifting state functionally maps the actuated state of the third shifting element (E) and connects the second drive shaft (10) in a rotationally fixed manner to the first drive shaft (9). [11] Motor vehicle transmission (2; 37; 41; 54) according to claim 10, characterized byin that the coupling element (32) is guided in a rotationally fixed and axially displaceable manner in each of the two switching states and during an axial displacement between its two switching states on a first toothing (33) which is connected in a rotationally fixed manner to the second drive shaft (10), wherein the coupling element (32) in its first switching state, with existing tooth engagement with the first toothing (33), additionally engages in a second toothing (34) which is connected in a rotationally fixed manner to the third element (E31) of the first planetary gear set (P1), and wherein the coupling element (32) in its second switching state, with existing tooth engagement with the first toothing (33), additionally engages in a third toothing (35) which is connected in a rotationally fixed manner to the first drive shaft (9). [12] Motor vehicle transmission (48) according to one of the preceding claims, characterized by that the second switching element (D) and the third switching element (E) are designed as individual switching elements. [13] Motor vehicle transmission (41) according to one of the preceding claims, characterized by in that a further, third planetary gear set (P3) is also provided, which has a first element (E13), a second element (E23) and a third element (E33) in the form of a sun gear (42), a planet carrier (43) and a ring gear (44), wherein one of the elements (E13, E23, E33) of the third planetary gear set (P3) is connected in a rotationally fixed manner to the output shaft (11), one of the elements (E13, E23, E33) of the third planetary gear set (P3) is connected in a rotationally fixed manner to an output shaft (46) and one of the elements (E13, E23, E33) of the third planetary gear set (P3) is fixed. [14] Drive unit (1; 36; 40; 47; 53) for an at least partially electrically driven motor vehicle, comprising a first electric machine (3), a second electric machine (4) and a motor vehicle transmission (2; 37; 41; 48; 54) according to one or more of claims 1 to 13, wherein a rotor (7) of the first electric machine (3) is coupled to the first drive shaft (9) of the motor vehicle transmission (2; 37; 41; 48; 54) and a rotor (8) of the second electric machine (4) is coupled to the second drive shaft (10) of the motor vehicle transmission (2; 37; 41; 48; 54). [15] Motor vehicle drive axle (59) for a hybrid or electric vehicle (57), comprising a drive unit (63) according to claim 14. [16] Hybrid or electric vehicle (57), comprising at least one motor vehicle drive axle (59) according to claim 13 or at least one drive unit (1; 36; 40; 47; 53) according to claim 14. [17] Method for operating a motor vehicle transmission (2; 37; 41; 48; 54) according to one or more of claims 1 to 13, - wherein in the motor vehicle transmission a gear (G2) is switched between the first drive shaft (9) and the output shaft (11) by representing the actuated state of the first switching element (B), - and wherein the gear (G2) is switched between both drive shafts (9, 10) and the output shaft (11) by simultaneously representing actuated states of the first switching element (B) and the third switching element (E). [18] Method according to claim 17, characterized by that only the actuated state of the second switching element (D) is represented and thereby a superposition operation (EDF) of the drive shafts (9, 10) on the first planetary gear set (P1) and the second planetary gear set (P2) is represented. [19] Method according to claim 17 or 18 and for operating a motor vehicle transmission (2; 37; 41; 48) according to one of claims 2 to 7, characterized by , - that in the motor vehicle transmission, a further gear (G1) is switched between the first drive shaft (9) and the output shaft (11) by displaying the actuated state of the further switching element (A), - that the further gear (G1) is switched between both drive shafts (9, 10) and the output shaft (11) by simultaneously displaying the actuated states of the further switching element (A) and the third switching element (E) - and that an intermediate gear (ZG) is switched between the second drive shaft (10) and the output shaft (11) by simultaneously displaying actuated states of the further switching element (A) and the second switching element (D). [20] Method according to one of claims 17 to 19 and for operating a motor vehicle transmission (37; 41; 54) according to one of claims 5 to 9, characterized by , - that in the motor vehicle transmission an additional gear (G3) is switched between the first drive shaft (9) and the output shaft (11) by representing the actuated state of the additional switching element (C), - and that the additional gear (G3) is switched between both drive shafts (9, 10) and the output shaft (11) by simultaneously representing actuated states of the additional switching element (C) and the second switching element (D) or the third switching element (E). [21] Method according to one of claims 17 to 19 and for operating a motor vehicle transmission (48) according to claim 12, characterized bythat an additional gear (G3) is switched between both drive shafts (9, 10) and the output shaft (11) by simultaneously representing actuated states of the second switching element (D) and the third switching element (E). [22] Method for operating a drive unit (1; 36; 40; 47; 53) according to claim 14, characterized by that the motor vehicle transmission (2; 37; 41; 48; 54) of the drive unit (1; 36; 40; 47; 53) is operable according to claims 17 and 18, wherein switching is carried out under load between a state (V; V'; V''; I'''), in which in the motor vehicle transmission (2; 37; 41; 48; 54) the gear (G2) is engaged between both drive shafts (9, 10) and the output shaft (11), and a state (III; III'; III''; III'''), in which in the motor vehicle transmission (2; 37; 41; 48; 54) the superposition operation (EDF) is represented, in that - on the one hand, switching between the second switching element (D) and the third switching element (E) and, for this purpose, a speed synchronisation is carried out on the third switching element (E) and on the second switching element (D) via the second electric machine (4) and a supporting of a tractive force is carried out via the first electric machine (3), - and secondly, switching between an actuated and an unactuated state of the first switching element (B) and for this purpose a load-free state is brought about on the first switching element (B) by the interaction of the two electric machines (3, 4). [23] Method according to claim 22 and for operating a drive unit (1; 36; 40; 47) with a motor vehicle transmission (2; 37; 41; 48) according to one of claims 2 to 7 and operable according to claims 17 to 19, characterized bythat switching is carried out under load between the state (III; III'; III''; III'''), in which the superposition operation (EDF) is represented in the motor vehicle transmission (2; 37; 41; 48; 54), and a state (I; I'; I''), in which the further gear (G1) is engaged between the two drive shafts (9, 10) and the output shaft (11) in the motor vehicle transmission (2; 37; 41; 48), by - on the one hand, switching between the second switching element (D) and the third switching element (E) and, for this purpose, a speed synchronisation is carried out on the third switching element (E) and on the second switching element (D) via the second electric machine (4) and a supporting of a tractive force is carried out via the first electric machine (3), - and secondly, switching between an actuated and an unactuated state of the further switching element (A) and for this purpose a load-free state is brought about on the further switching element (A) by the interaction of the two electric machines (3, 4). [24] Method according to claim 22 or 23 and for operating a drive unit (36; 40; 53) with a motor vehicle transmission (37; 41; 54) according to one of claims 5 to 9 and operable according to claims 17, 18 and 20, characterized by that switching takes place under load between the state (III'; III''; III'''), in which the superposition operation (EDF) is represented in the motor vehicle transmission (37; 41; 54), and a state (VI'; VII'; VI'''; VII'''), in which the additional gear (G3) is engaged between both drive shafts (9, 10) and the output shaft (11), in that - switching between an actuated and an unactuated state of the additional switching element (C) and for this purpose a load-free state is brought about on the additional switching element (C) by the interaction of the two electric machines (3, 4).

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