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

Abstract

The invention relates to a motor vehicle transmission (3) comprising a drive shaft (6), an output shaft (7), a stepped planetary gear set (P1), and a planetary gear set (P2). Furthermore, a first shifting element (A) and a second shifting element (B) are provided, at least functionally, in the motor vehicle transmission (3).

Description

[0001] The invention relates to a motor vehicle transmission for an at least partially electrically driven motor vehicle, comprising a drive shaft which is provided for a drive-effective connection to at least one drive machine, preferably at least one electric machine, an output shaft and a stepped planetary gear set which has a first element, a second element, a third element and a fourth element in the form of a sun gear, a planet carrier, a ring gear and either a further sun gear or a further ring gear, wherein the planet carrier of the stepped planetary gear set rotatably supports at least one stepped planetary gear which is in meshing engagement with the sun gear, the ring gear and either the further sun gear or the further ring gear, wherein the fourth element of the stepped planetary gear set is connected in a rotationally fixed manner to the drive shaft,whereas the first element of the stepped planetary gear set is fixed to a housing-fixed component, wherein a planetary gear set is also provided, which has a first element, a second element and a third element in the form of a sun gear, a ring gear and a planet carrier, wherein the second element of the planetary gear set is connected in a rotationally fixed manner to the output shaft, whereas the third element of the planetary gear set is fixed, and wherein at least functionally a first switching element and a second switching element are provided, of which the at least functionally provided first switching element, in an actuated state, connects the second element of the stepped planetary gear set in a rotationally fixed manner to the first element of the planetary gear set, whereas the at least functionally provided,The second shift element, in an actuated state, connects the third element of the stepped planetary gear set to the first element of the planetary gear set in a rotationally fixed manner. Furthermore, the invention relates to a drive unit for an at least partially electrically driven motor vehicle, an electrically driven motor vehicle drive axle for an at least partially electrically driven motor vehicle, a hybrid or electric vehicle, and a method for operating a motor vehicle transmission.

[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] DE 10 2021 208 564 B3 discloses a drive train for an electric vehicle. In this drive train, an electric motor is connected in a rotationally fixed manner to a drive shaft of a downstream motor vehicle transmission, which, in addition to a differential gear set and a planetary gear set, also has a stepped planetary gear set. The stepped planetary gear set has a planet carrier that rotatably supports at least one stepped planetary gear, wherein the at least one stepped planetary gear meshes with a sun gear and a first ring gear at a first toothing and meshes with a second ring gear at a second toothing. While the sun gear is connected in a rotationally fixed manner to the drive shaft, the planet carrier of the stepped planetary gear set is permanently fixed.Furthermore, in a variant of DE 10 2021 208 564 B3, a switching device is provided which replicates the function of two switching elements. In a first switching state, the switching device connects the first ring gear of the stepped planetary gear set and, in a second switching state, the second ring gear of the stepped planetary gear set, each rotationally fixed to a ring gear of the downstream planetary gear set. In the planetary gear set, a sun gear is permanently fixed, while a planet carrier of the planetary gear set is rotationally fixed to an output shaft, which is also rotationally fixed to an input element of the differential gear set. The output shaft is coupled to two output shafts via the differential gear set.

[0004] Starting from the prior art described above, it is the object of the present invention to provide an alternative embodiment of a motor vehicle transmission which is suitable for the integration of a drive motor, preferably an electric motor, and which is designed to be as compact as possible.

[0005] This object is achieved based on the preamble of claim 1 in conjunction with its characterizing features. The dependent claims that follow 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 16 or 17. Furthermore, claim 18 relates to an electrically driven motor vehicle drive axle for an at least partially electrically driven motor vehicle, while claim 19 relates to a hybrid or electric vehicle. Finally, claim 20 relates to a method for operating a motor vehicle transmission according to the invention.

[0006] According to the invention, a motor vehicle transmission comprises a drive shaft provided for a drive-effective connection to at least one drive motor, preferably at least one electric motor, an output shaft, and a stepped planetary gear set having a first element, a second element, a third element, and a fourth element in the form of a sun gear, a planet carrier, a ring gear, and either a further sun gear or a further ring gear. The planet carrier of the stepped planetary gear set rotatably supports at least one stepped planetary gear, which meshes with the sun gear, the ring gear, and either the further sun gear or the further ring gear. The fourth element of the stepped planetary gear set is connected in a rotationally fixed manner to the drive shaft, whereas the first element of the stepped planetary gear set is fixed to a component fixed to the housing.

[0007] In addition, a planetary gear set is provided which has a first element, a second element and a third element in the form of a sun gear, a ring gear and a planet carrier, wherein the second element of the planetary gear set is connected in a rotationally fixed manner to the output shaft, whereas the third element of the planetary gear set is fixed. At least functionally, a first switching element and a second switching element are also provided, of which the at least functionally provided first switching element, in an actuated state, connects the second element of the stepped planetary gear set in a rotationally fixed manner to the first element of the planetary gear set, whereas the at least functionally provided second switching element, in an actuated state, connects the third element of the stepped planetary gear set in a rotationally fixed manner to the first element of the planetary gear set.

[0008] A respective “shaft”, such as the drive shaft and the output shaft of the motor vehicle transmission according to the invention, is understood within the meaning of the invention to be a rotatable component of the motor vehicle transmission via which a power flow can be guided between components. The respective shaft can connect these components to one another axially or radially, or even both axially and radially, with power flow guidance. The respective shaft can therefore also be in the form of an intermediate piece via which, for example, a purely radial connection is realized. Furthermore, the respective shaft can be designed as a solid shaft, a hollow shaft, or partly as a solid and partly as a hollow shaft, depending on its course and connection to the components. Alternatively or additionally, the respective shaft can be designed in one or more parts.

[0009] The motor vehicle transmission according to the invention has a drive shaft which, in the motor vehicle transmission according to the invention, is provided for establishing a drive-side coupling to at least one drive motor, wherein the drive shaft preferably serves for coupling to exactly one drive motor. For this purpose, the drive shaft is equipped in particular with a connection point at which a coupling of the drive shaft to the at least one drive motor can be formed. The connection of the at least one drive motor to the connection point of the drive shaft is particularly permanent in the installed state of the motor vehicle transmission, preferably when the drive motor is designed as an electric motor. Alternatively, however, an intermediate starting element, such as a hydrodynamic torque converter, a starting clutch, etc., can also be used., through which the drive shaft can be or is coupled to the upstream drive motor at its connection point. This is particularly achieved when the drive motor is designed as an internal combustion engine.

[0010] The coupling between the at least one drive motor and the 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 drive shaft of the motor vehicle transmission and a speed of the 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 drive shaft and the drive motor, via which a pre-transmission of a rotary movement of the drive motor to the drive shaft can be realized. However, the drive shaft preferably serves as a rotationally fixed connection to the at least one drive motor.

[0011] The motor vehicle transmission is, in particular, a hybrid or electric vehicle transmission, which is intended to be connected to a drive unit in the form of an electric motor at the drive shaft. A rotor of the electric motor can, as described above, be coupled to the drive shaft of the transmission via at least one intermediate gear ratio. However, a rotor of the electric motor is particularly preferably connected to the drive shaft in a rotationally fixed manner in the installed state of the motor vehicle transmission according to the invention.

[0012] 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 at least one drive motor connected to the drive shaft to the drive wheels of the respective motor vehicle can be established in order to transmit a drive movement generated by the drive motor to the drive wheels with different transmission ratios.

[0013] The stepped planetary gear set of the motor vehicle transmission according to the invention consists of a sun gear, a ring gear, a planet carrier, and either a further sun gear or a further ring gear, with at least one stepped planetary gear being rotatably mounted in the planet carrier. The stepped planetary gear set thus comprises four elements: a sun gear, a ring gear, a planet carrier, and either a further sun gear or a further ring gear. The at least one stepped planetary gear meshes with the sun gear, the ring gear, and also with the further sun gear or the further ring gear.For this purpose, the at least one stepped planetary gear is equipped, in particular, with two different, axially adjacent toothings, wherein the tooth meshing with one sun gear and one ring gear takes place at one toothing, while the tooth meshing with the other sun gear or the other ring gear takes place at the other toothing. Preferably, the toothings are configured with different numbers of teeth on different diameters of the stepped planetary gear.

[0014] Within the scope of the invention, these different toothings can be provided on a one-piece stepped planetary gear, wherein the at least one stepped planetary gear is preferably composed of two coaxial spur gears connected to one another in a rotationally fixed manner, of which one spur gear is provided with one toothing on an outer circumference and meshes with one sun gear and one ring gear, while the other spur gear has the other toothing on an outer circumference and meshes with the other sun gear or the other ring gear.

[0015] In addition to the stepped planetary gear set, the motor vehicle transmission according to the invention provides a planetary gear set which is composed of a first element, a second element and a third element. Of these elements, one element is designed as a sun gear, one element as a planet carrier and one element as a ring gear. The planetary gear set is preferably a minus planetary gear set in which the planet carrier guides at least one planetary gear in a rotatable manner, wherein the at least one planetary gear is in meshing engagement with both the sun gear of the planetary gear set and the ring gear of the planetary gear set. In particular, a plurality of planetary gears are rotatably guided in the planet carrier. Alternatively, the planetary gear set could also be designed as a plus planetary gear set.In this case, at least one pair of planetary gears is rotatably mounted in the planetary carrier of the planetary gear set, one of whose planetary gears meshes with the sun gear of the planetary gear set, and one with the ring gear of the planetary gear set. Furthermore, the planetary gears of at least one pair of planetary gears mesh with each other.

[0016] The invention now includes the technical teaching that the third element of the planetary gear set is connected in a rotationally fixed manner to the first element of the stepped planetary gear set and is connected in a rotationally fixed manner to the housing-fixed component via the intermediate, first element of the stepped planetary gear set.

[0017] In the motor vehicle transmission according to the invention, the fourth element of the stepped planetary gear set is therefore permanently connected in a rotationally fixed manner to the drive shaft, so that the drive shaft and the fourth element of the stepped planetary gear set always rotate together. Furthermore, the first element of the stepped planetary gear set is permanently fixed to a component fixed to the housing, whereby the first element of the stepped planetary gear set is permanently prevented from rotating. The output shaft is also permanently connected in a rotationally fixed manner to the second element of the planetary gear set, so that the second element of the planetary gear set and the output shaft always rotate together. Furthermore, the third element of the planetary gear set is also permanently fixed and thus permanently prevented from rotating. This is achieved by the third element of the planetary gear set being rotationally fixed to the first element of the stepped planetary gear set.Since the first element of the stepped planetary gear set is connected in a rotationally fixed manner to the housing-fixed component, the third element of the planetary gear set is thereby fixed indirectly via the first element of the stepped planetary gear set.

[0018] The motor vehicle transmission according to the invention at least functionally comprises a first shifting element and a second shifting element. An actuated state of the at least functionally provided first shifting element results in a rotationally fixed connection of the second element of the stepped planetary gear set and the first element of the planetary gear set, so that the second element of the stepped planetary gear set and the first element of the planetary gear set then rotate together. The first element of the planetary gear set can also be rotationally fixedly connected to the third element of the stepped planetary gear set by bringing about the actuated state of the at least functionally provided second shifting element. As a result, the third element of the stepped planetary gear set and the first element of the planetary gear set then rotate together.

[0019] Such a design of a motor vehicle transmission has the advantage that, through the integration of the stepped planetary gear set and the planetary gear set and through the selective actuation of the at least functionally provided shifting elements, high gear ratios can be achieved, which are each particularly suitable for the integration of a drive motor in the form of an electric machine. Thus, through the selective actuation of the two at least functionally provided shifting elements, different power flow guidances can be implemented via the stepped planetary gear set, with an additional gear ratio being then provided to the output shaft via the downstream planetary gear set. Due to the indirect fixing of the third element of the planetary gear set via the first element of the stepped planetary gear set, a compact design of the motor vehicle transmission can also be achieved.The planetary gear set can then be positioned radially further inward, allowing a smaller diameter of the planetary gear set's sun gear and thus a higher stationary gear ratio. This results in a compact motor vehicle transmission with high gear ratios.

[0020] A first gear can be engaged between the drive shaft and the output shaft by representing an actuated state of the first shifting element. Furthermore, a second gear can be engaged between the drive shaft and the output shaft by representing an actuated state of the second shifting element.

[0021] In the motor vehicle transmission according to the invention, the input shaft and the output shaft are arranged coaxially to one another, with the stepped planetary gear set and the planetary gear set also preferably being positioned coaxially to the input shaft and the output shaft. This allows for a particularly compact design of the motor vehicle transmission in the radial direction.

[0022] 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 stepped planetary gear set and the planetary gear set 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 a respective element of the stepped planetary gear set or the planetary gear set.

[0023] Very particularly preferably, in the motor vehicle transmission according to the invention, for shifting different gears between the drive shaft and the output shaft, at least in terms of function, there are exactly two shifting elements in the form of the first shifting element and the second shifting element, although within the scope of the invention, further shifting elements that are provided at least functionally can also be provided 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. In this case, the respective shifting element can actually be physically present as a single shifting element, or the function of the respective shifting element is represented by another component, such as a switching device.A component that maps the function can then combine the function of two switching elements in one device.

[0024] For the purposes of the invention, a "torsion-proof" 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.

[0025] The housing-fixed component 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. In this case, the first element of the stepped planetary gear set is directly or indirectly connected in a rotationally fixed manner to the housing-fixed component, while the third element of the planetary gear set is indirectly connected in a rotationally fixed manner to the housing-fixed component via at least the intermediate, first element of the stepped planetary gear set. In this case, the first element of the stepped planetary gear set can be designed as a single piece with the housing-fixed component, in which case the third element of the planetary gear set could also be designed as a single piece with the housing-fixed component and the first element of the stepped planetary gear set.

[0026] Within the meaning of the invention, a rotationally fixed connection between components of the motor vehicle transmission via an at least functionally provided shifting element means that the components are not permanently coupled to one another, but rather a rotationally fixed connection is only established upon the activation of the at least functionally provided intermediate shifting element. An activated state of the at least functionally provided shifting element within the meaning of the invention means that the respective shifting element 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.

[0027] According to one embodiment of the invention, the first element of the stepped planetary gear set is the planet carrier of the stepped planetary gear set, the second element of the stepped planetary gear set is the ring gear of the stepped planetary gear set, the third element of the stepped planetary gear set is the further ring gear of the stepped planetary gear set, and the fourth element of the stepped planetary gear set is the sun gear of the stepped planetary gear set. In this case, the stepped planetary gear set has, in addition to the planet carrier, exactly one sun gear and exactly two ring gears. The planet carrier of the stepped planetary gear set forms the first element of the stepped planetary gear set, while the second element of the stepped planetary gear set is represented by one ring gear, the third element of the stepped planetary gear set by the other ring gear, and the fourth element of the stepped planetary gear set by exactly one sun gear.

[0028] In a further development of this embodiment, the at least one stepped planetary gear of the stepped planetary gear set is in meshing engagement with the sun gear of the stepped planetary gear set and the further ring gear of the stepped planetary gear set on a first toothing each, wherein the at least one stepped planetary gear of the stepped planetary gear set also meshes with the ring gear of the stepped planetary gear set on a second toothing each.

[0029] According to one possible embodiment of the invention, the output shaft is coupled to an input element of a differential gear set, which drive-effectively connects the output shaft to two output shafts. Advantageously, this 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.

[0030] 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. When the motor vehicle transmission is installed in the direction of travel and the differential gear set is used 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 provided as a longitudinal differential and the motor vehicle transmission is aligned transversely to the direction of travel.

[0031] Particularly preferably, in the motor vehicle transmission according to the invention, the design option according to which the output shaft is coupled to an input element of a differential gear set is combined with the previous variant. In this case, the differential gear set is then located axially overlapping the tooth engagement established between the at least one stepped planetary gear of the stepped planetary gear set and the ring gear, as well as radially inward of the planet carrier of the stepped planetary gear set. This enables a nested arrangement of the differential gear set with the stepped planetary gear set, with the differential gear set at least partially axially overlapping the tooth engagement of the at least one stepped planetary gear with the ring gear. This allows the axial length of the motor vehicle transmission to be reduced.Alternatively or additionally, the differential gear set can also be arranged axially overlapping and radially inward of the planetary gear set, which also makes it possible to reduce the axial length of the motor vehicle transmission.

[0032] In a further development of the invention, a differential lock is assigned to the differential gear set, which, when actuated, connects one of the output shafts in a rotationally fixed manner to the input element or connects the two output shafts in a rotationally fixed manner to each other. Thus, by selectively actuating the differential lock, the effect of the differential gear set can be specifically prevented, thus forcing synchronization of the two output shafts. In principle, the differential lock can be implemented as a force-locking clutch or as a form-locking clutch. In the latter case, a design as a movable driving toothing would be conceivable, which, in a locked position, engages both on the side of one of the output shafts and on the side of the input element, thereby establishing the rotationally fixed connection.

[0033] According to one embodiment of the invention, the first shifting element and the second shifting element are formed by a common shifting device having a coupling element. The 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 represents an actuated state of the first shifting element and connects the second element of the stepped planetary gear set in a rotationally fixed manner to the first element of the planetary gear set. In its second shifting state, the coupling element then functionally represents an actuated state of the second shifting element and connects the third element of the stepped planetary gear set in a rotationally fixed manner to the first element of the planetary gear set. As a result, the function of the first shifting element and the second shifting element can be represented by one shifting device and thus in a compact manner.Furthermore, only one common actuator is required to represent the actuated states, via which the coupling element can be positioned in the respective different switching positions. Preferably, the coupling element can also be transferred to a neutral state between the switching states, in which neither an actuated state of the first switching element nor an actuated state of the second switching element is represented.

[0034] The aforementioned switching device is designed in particular such that the coupling element, in its two switching states and during axial displacement between its two switching states, is guided in a rotationally fixed manner on a first toothing which is rotationally fixedly connected to the first element of the planetary gear set. In the first switching state, the coupling element then additionally engages with a second toothing when the toothing is engaged with the first toothing, which is rotationally fixedly connected to the second element of the stepped planetary gear set. In its second switching state, the coupling element additionally engages with a third toothing when the toothing is engaged with the first toothing, which is rotationally fixedly connected to the third element of the stepped planetary gear set.

[0035] The coupling element of the switching device is in particular a sliding sleeve. The coupling element preferably has one or more coupling teeth, on which the axial, rotationally fixed guidance on the first toothing takes place and / or the respective engagement with the second and third toothing can be carried out. The teeth are preferably designed as claw teeth, so that the switching device replicates the function of unsynchronized claw switching elements. Alternatively, the first switching element and the second switching element could also be in the form of individual switching elements, wherein the switching elements in this case are designed in particular as positive-locking switching elements and, in this case, particularly preferably as unsynchronized claw switching elements.Alternatively, individual switching elements could also be designed as locking synchronizations or as force-locking switching elements, in particular in the form of lamella switching elements.

[0036] In a further embodiment of the invention, a parking lock element is also provided, which, in an actuated state, directly or indirectly locks the output shaft. This advantageously allows a parking lock function to be implemented in the motor vehicle transmission according to the invention by actuating the parking lock element. Upon activation of the parking lock function, the output shaft is locked, thereby reliably preventing a motor vehicle having the motor vehicle transmission according to the invention from rolling away.

[0037] Within the scope of the invention, the parking lock element can, when actuated, directly connect the output shaft in a rotationally fixed manner to a component fixed to the housing. However, the parking lock element is particularly preferably arranged in the power flow between two of the elements of the planetary gear set and, when actuated, connects these two elements of the planetary gear set to one another in a rotationally fixed manner. As a result, when actuated, the parking lock element causes the planetary gear set to lock, which, due to the permanently rotationally fixed connection of the output shaft to the second element of the planetary gear set and the constantly locked state of the third element of the planetary gear set, also results in the output shaft becoming locked. The advantage here is that with this arrangement the parking lock element can be made smaller because, due to the interposition of the planetary gear set, a lower torque is applied than with a direct connection to the output shaft.The parking lock element can be arranged in the power flow between the first element and the second element of the planetary gear set, the first element and the third element of the planetary gear set or the second element and the third element of the planetary gear set.

[0038] Particularly preferably, the parking lock element causes the planetary gear set to lock upon actuation, in that the parking lock element immobilizes the first element of the planetary gear set or the second element of the planetary gear set. Within the scope of the invention, the parking lock element can then be arranged axially overlapping and radially surrounding the planetary gear set, or it can be positioned axially on a side of the planetary gear set facing away from the stepped planetary gear set. If a differential gear set with a differential lock is also provided, the differential lock and the parking lock element can also be combined.

[0039] The parking lock element is, in particular, an additional shifting element, which, however, is not intended to implement a transmission ratio between the drive shaft and the output shaft, but rather serves to directly or indirectly lock the output shaft. The parking lock element is preferably a positive-locking shifting element, in particular a claw-type shifting element, although the parking lock element could equally well be designed as a non-positive-locking shifting element.

[0040] In a further embodiment of the invention, the third element of the planetary gear set is the sun gear of the planetary gear set, whereas the second element of the planetary gear set is the planet carrier of the planetary gear set when the planetary gear set is designed as a negative planetary gear set and the ring gear of the planetary gear set when the planetary gear set is designed as a positive planetary gear set. The first element of the planetary gear set is the ring gear of the planetary gear set when the planetary gear set is designed as a negative planetary gear set and the planet carrier of the planetary gear set when the planetary gear set is designed as a positive planetary gear set. The third element of the planetary gear set is therefore in the form of a sun gear, whereas the second element of the planetary gear set is the planet carrier when the planetary gear set is designed as a negative planetary gear set, while the second element of the planetary gear set is a ring gear when the planetary gear set is designed as a positive planetary gear set.If the planetary gear set is designed as a minus planetary gear set, the third element is the ring gear of the planetary gear set, whereas if the planetary gear set is designed as a plus planetary gear set, the third element is the planet carrier of the planetary gear set.

[0041] Alternatively, the first element of the planetary gear set is the sun gear of the planetary gear set, whereas the second element of the planetary gear set is the planet carrier of the planetary gear set when the planetary gear set is designed as a negative planetary gear set and the ring gear of the planetary gear set when the planetary gear set is designed as a positive planetary gear set. The third element of the planetary gear set is the ring gear of the planetary gear set when the planetary gear set is designed as a negative planetary gear set and the planet carrier of the planetary gear set when the planetary gear set is designed as a positive planetary gear set. In this case, the first element of the planetary gear set is the sun gear, both when it is designed as a negative planetary gear set and when it is designed as a positive planetary gear set.If the planetary gear set is a minus planetary gear set, the second element is the planet carrier and the third element is the ring gear, whereas if the planetary gear set is a plus planetary gear set, the second element is the ring gear and the third element is the planet carrier.

[0042] The invention also relates to a drive unit which, in addition to at least one electric machine, has a motor vehicle transmission according to one or more of the variants described above. In this case, a rotor of each of the at least one electric machine is coupled to the drive shaft of the motor vehicle transmission. The at least one electric machine can, within the scope of the invention, be operated in particular both as a generator and 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. In this case, it is particularly preferable for the drive unit to provide exactly one electric machine in addition to the motor vehicle transmission.

[0043] The at least one electric machine is preferably connected in a rotationally fixed manner to the drive shaft of the motor vehicle transmission, wherein the at least one electric machine is then arranged coaxially to the drive shaft. As a result, the drive shaft and the respective rotor of the at least one electric machine run at the same speed during operation. Alternatively, it is also conceivable for the respective rotor of the at least one electric machine to be connected in a rotationally fixed manner to an intermediate shaft of the motor vehicle transmission, which is coupled to the drive shaft via at least one gear ratio, so that the at least one electric machine is then possibly offset axially from the drive shaft. Depending on the design of the at least one gear ratio, a coaxial arrangement of the at least one electric machine to the drive shaft is also possible.

[0044] Preferably, the stepped planetary gear set of the motor vehicle transmission is positioned axially between the at least one electric motor and the planetary gear set of the motor vehicle transmission. This allows for a suitable design of a drive unit.

[0045] A drive unit designed according to one of the aforementioned variants is, in particular, part of an electrically driven motor vehicle drive axle, which is intended for an electric or hybrid vehicle. The motor vehicle transmission preferably has a differential gear set coupled to the output shaft and thereby coupling the output shaft to output shafts. Each of the output shafts is assigned to a drive wheel of the motor vehicle drive axle.

[0046] Within the scope of the invention, the aforementioned motor vehicle drive axle is provided for 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.

[0047] Advantageous embodiments of the invention, which are explained below, are illustrated in the drawings. They show: Fig. 1 to 4 each show a schematic representation of a drive unit according to an embodiment of the invention; Fig. 5 an exemplary circuit diagram of a respective motor vehicle transmission of the respective drive unit from the Fig. 1 to 4; and Fig. 6 is a schematic view of an electric vehicle according to a preferred embodiment of the invention.

[0048] Out of Fig. Figure 1 shows a schematic view of a drive unit 1 designed according to one embodiment of the invention. This drive unit 1 consists of an electric machine 2 and a motor vehicle transmission 3, which is designed according to one possible embodiment of the invention. The electric machine 2 is formed in a manner known in principle to those skilled in the art by a stator 4 and a rotor 5, whereby the electric machine 2 can be operated both as a generator and as an electric motor.

[0049] The motor vehicle transmission 3 has, in addition to an input shaft 6 and an output shaft 7, a stepped planetary gear set P1 and a planetary gear set P2. The stepped planetary gear set P1 comprises a first element E11, a second element E21, a third element E31, and a fourth element E41. While the first element E11 of the stepped planetary gear set P1 is a planet carrier 8, the second element E21 and the third element E31 are each a ring gear 9 and 10, respectively. The fourth element E41 of the stepped planetary gear set P1, in contrast, is designed as a sun gear 11.

[0050] As in Fig. As can be seen in Figure 1, at least one stepped planetary gear 12 is rotatably mounted in the planet carrier 8 of the stepped planetary gear set P1, said gear having two axially adjacent toothings 13 and 14. While tooth engagements with the sun gear 11 and the ring gear 10 are established at the toothing 13, the at least one stepped planetary gear 12 meshes with the ring gear 9 at the toothing 14.

[0051] The planetary gear set P2 has a first element E12, a second element E22, and a third element E32. The third element E32 of the planetary gear set P2 is a sun gear 15 of the planetary gear set P1, the second element E22 of the planetary gear set P2 is a planet carrier 16 of the planetary gear set P2, and the first element E12 of the planetary gear set P2 is a ring gear 17 of the planetary gear set P2. At least one planetary gear 18 is rotatably mounted in the planet carrier 16, which meshes with both the sun gear 15 and the ring gear 17. In this respect, the planetary gear set P2 is designed as a minus planetary gear set.

[0052] In this case, the fourth element E41 of the stepped planetary gear set P1 is rotationally fixedly connected to the drive shaft 6, which is also rotationally fixedly connected to the rotor 5 of the electric machine 2. Thus, the fourth element E41 of the stepped planetary gear set P1 and the rotor 5 are also rotationally fixedly connected to one another via the drive shaft 6, whereby the fourth element E41 and the rotor 5 always rotate at the same speed. Within the scope of the invention, the drive shaft 6 can be designed as a single piece with the rotor 5 of the electric machine 2 and / or with the sun gear 11 of the stepped planetary gear set P1 forming the fourth element E41.

[0053] The first element E11 of the stepped planetary gear set P1 is permanently connected in a rotationally fixed manner to a housing-fixed component 19, which is preferably a transmission housing of the motor vehicle transmission 3, a part of such a transmission housing, or a component rotationally fixed thereto. In this respect, the first element E11 of the stepped planetary gear set P1 is permanently fixed. The third element E32 of the planetary gear set P2 is also permanently fixed, whereby in the present case this is achieved in that the third element E32 of the planetary gear set P2 is rotationally fixedly connected to the first element E11 of the stepped planetary gear set P1 and is thereby indirectly fixed to the housing-fixed component 19 via the intermediate first element E11 of the stepped planetary gear set P1. Within the scope of the invention, a one-piece design of the first element E11 of the stepped planetary gear set P1 and, if necessary, furtheralso the third element E32 of the planetary gear set P2 with the housing-fixed component 19.

[0054] The output shaft 7 is permanently connected in a rotationally fixed manner to the second element E22 of the planetary gear set P2, whereby the output shaft 7 is also permanently connected in a rotationally fixed manner to an input element 20 in the form of a differential cage of a differential gear set 21. This differential gear set 21 is designed as a bevel gear differential, which, in a manner known in principle to those skilled in the art, distributes a drive torque introduced into the input element 20 via the output shaft 7 between two output shafts 22 and 23. The differential gear set 21 also enables speed differences between the output shafts 22 and 23.

[0055] The motor vehicle transmission 3 also has a shifting device 24, in which a coupling element 25 in the form of a sliding sleeve is provided. The coupling element 25 is guided in a rotationally fixed and axially displaceable manner on a toothing 26, which is rotationally fixedly connected to the first element E12 of the planetary gear set P2. Axial displacements of the coupling element 25 on the toothing 26 can be performed via a control actuator (not shown here), which is preferably designed as an electromechanical control actuator.

[0056] The coupling element 25 can be transferred via the actuating actuator between two different switching states, in each of which a tooth engagement of the coupling element 25 is effected with a respective associated toothing 27 or 28. Toothing 27 is connected in a rotationally fixed manner to the second element E21 of the stepped planetary gear set P1, while toothing 28 is connected in a rotationally fixed manner to the third element E31 of the stepped planetary gear set P1.

[0057] The switching device 24 thereby represents the function of two switching elements A and B, whose respective actuated state is represented by the switching device 24 in each of its switching states. Thus, an actuated state of the switching element A is realized in a first switching state of the coupling element 25, in which the coupling element 25, with existing tooth engagement with the toothing 26, additionally engages the toothing 27 and thus connects the second element E21 of the stepped planetary gear set P1 in the form of the ring gear 9 in a rotationally fixed manner to the first element E12 of the planetary gear set P2. From the first switching state, the coupling element 25 can be moved via the actuating actuator into a neutral state, which in Fig. 1 and in which the coupling element 25 is only in meshing engagement with the toothing 26 and therefore no coupling is carried out via the coupling element 25.

[0058] In addition to transferring the coupling element 25 to the first switching state, the coupling element 25 can also be moved from the neutral state to a second switching state, in which, while the tooth meshing with the toothing 26 is present, the coupling element 25 additionally engages the toothing 28. As a result, the coupling element 25 connects the third element E31 of the stepped planetary gear set P1 in a rotationally fixed manner to the first element E12 of the planetary gear set P2, which corresponds to an actuated state of the switching element B.

[0059] In this case, the electric machine 2 is positioned coaxially to the motor vehicle transmission 3, in which the input shaft 6, the stepped planetary gear set P1 and the planetary gear set P2, the output shaft 7, the output shafts 22 and 23, and the differential gear set 21 are also arranged coaxially to one another. The stepped planetary gear set P1 is arranged axially between the electric machine 2 and the planetary gear set P2, with the differential gear set 21 axially overlapping the stepped planetary gear set P1. Specifically, the differential gear set 21 axially overlaps the tooth engagement of the stepped planetary gear 12 with the ring gear 9 and is radially inward of the planet carrier 8. At the same time, the differential gear set 21 axially overlaps the planetary gear set P2 and is provided radially inward of it. This results in a nested arrangement of the stepped planetary gear set P1, the planetary gear set P2 and the differential gear set 21.The switching device 24 is arranged radially surrounding the stepped planetary gear set P1 and the planetary gear set P2, wherein the switching device 24 is placed axially substantially overlapping the stepped planetary gear set P1, the planetary gear set P2 and the differential gear set 21.

[0060] The output shaft 7 runs on a side of the planetary gear set P2 facing away from the stepped planetary gear set P1 as a radial connecting piece, connecting the second element E22 of the planetary gear set P2 and the input element 20. While the output shafts 22 and 23 are designed as solid shafts, the input shaft 6 and the output shaft 7 are hollow shafts.

[0061] Furthermore, Fig. 2 a schematic view of a drive unit 29 according to a further embodiment of the invention, this embodiment being largely similar to the previous variant Fig. 1. In contrast to the drive unit 1 from Fig. 1, in a motor vehicle transmission 30 of the drive unit 29, the first element E12 of the planetary gear set P2 is now the sun gear 15, while the third element E32 of the planetary gear set P2 is the ring gear 17.

[0062] Furthermore, the motor vehicle transmission 30 additionally has a parking lock element P, in whose actuated state the output shaft 7 is indirectly locked. The parking lock element P is arranged in the power flow between a shaft 31, which connects the first element E12 of the planetary gear set P2 to the gearing 26, and the housing-fixed component 19. In an actuated state, it locks the shaft 31 to the housing-fixed component 19, whereby the first element E12 and the third element E32 of the planetary gear set P2 are ultimately connected to one another in a rotationally fixed manner. This results in the planetary gear set P2 becoming blocked, so that the output shaft 7 is also locked due to the permanently locked state of the third element E32 of the planetary gear set P2.

[0063] The parking lock element P is designed here as a positive-locking shift element, with the parking lock element P specifically being designed as a claw shift element. Furthermore, the parking lock element P is arranged axially overlapping the planetary gear set P2 and radially surrounding it.

[0064] For the connection to the first element E12 of the planetary gear set P2, the shaft 31 is guided axially from the axial side facing the stepped planetary gear set P1 radially outward to the planetary gear set P2 on the opposite axial side. Furthermore, the output shaft 7 on the axial side of the planetary gear set P2 facing the stepped planetary gear set P1 forms the connection between the second element E22 and the input element 20 as a short radial connecting piece. As a result, the planetary gear set P2 can be Fig. 1 is arranged radially further inward and thus a higher stationary transmission ratio can be easily achieved. Otherwise, the design according to Fig. 2 of the variant Fig. 1, so that reference is made to what has been described in this regard.

[0065] Furthermore, Fig. 3 shows a schematic view of a drive unit 32 according to a further embodiment of the invention. This drive unit 32 largely corresponds to the drive unit 29 of Fig. 2, with the difference that the parking lock element P is now arranged axially on a side of the planetary gear set P2 facing away from the stepped planetary gear set P1. Furthermore, the design option according to Fig. 3 otherwise according to the variant Fig. 2, so that reference is made to what has been described therein.

[0066] Out of Fig. 4 shows a schematic representation of a drive unit 34 which is designed according to a further embodiment of the invention and largely corresponds to the drive unit 32 of Fig. 3. The only difference is that in a motor vehicle transmission 35 of the drive unit 34, a differential lock 36 is now provided, which is axially displaceable and consists of a Fig. 4 shown neutral position into a locking position, in which the differential lock 36 connects the input element 20 in a rotationally fixed manner to the output shaft 23. This forces the two drive shafts 22 and 23 to rotate synchronously. To establish the rotationally fixed connection, the differential lock 36 is preferably equipped with corresponding drive gears. Otherwise, the embodiment according to Fig. 4 of the variant Fig. 3, so that reference is made to what has been described in this regard.

[0067] In Fig. 5 is an exemplary circuit diagram of the motor vehicle transmissions 3, 30, 33 and 35 from the Fig. 1 to 4 are shown in tabular form. As can be seen, a total of two gears G1 and G2 can be realized between the input shaft 6 and the output shaft 7, with an X in the columns of the shift diagram indicating which actuated states of the shift elements A and B formed by the shift device 24 are to be represented in the individual gear. In each of the gears G1 and G2, an actuated state is to be represented for each of the shift elements A and B.

[0068] As in Fig. 5, a first gear G1 is shifted between the drive shaft 6 and the output shaft 7 by displaying the actuated state of the shifting element A in the shifting device 24. To shift a second gear G2, the actuated state of the shifting element B must then be realized in the shifting device 24. Synchronization of speeds when engaging a respective gear can at least be supported by a corresponding braking or acceleration of the drive shaft 6 via the electric machine 2, this being carried out in the course of displaying the neutral state of the coupling element 25 of the shifting device 24.

[0069] Finally, Fig. 6 shows a schematic view of an electric vehicle 37, which may in particular be an electric commercial vehicle, such as a van. In addition to a steerable, non-driven vehicle axle 38, the electric vehicle 37 also has a motor vehicle drive axle 39 with drive wheels 40 and 41. Part of the motor vehicle drive axle 39 is also a drive unit 42, which corresponds to one of the drive units 1, 29, 32 and 34 from the Fig. 1 to 4. The drive wheel 40 is connected in a rotationally fixed manner to the output shaft 22 of the drive unit 42, while the drive wheel 41 is connected in a rotationally fixed manner to the output shaft 23 of the drive unit 42.

[0070] While the vehicle axle 38 is a front axle of the electric vehicle 37, the motor vehicle drive axle 39 is a rear axle of the electric vehicle 37. However, alternatively or in addition to the motor vehicle drive axle 39, the vehicle axle 38 could also be designed as a driven axle with, if appropriate, an analogous structure of a drive unit.

[0071] By means of the design according to the invention, a compact motor vehicle transmission with suitable gear ratios for the integration of an electric motor can be realized. Reference symbol 1 drive unit 2 electric machine 3 Motor vehicle transmissions 4 Stator 5 Rotor 6 Drive shaft 7 Output shaft 8 planet carriers 9 ring gear 10 ring gear 11 Sun gear 12-stage planetary gear 13 Gearing 14 Gearing 15 Sun gear 16 planet carriers 17 Ring gear 18 Planetary gear 19 housing-fixed component 20 input element 21 Differential gear set 22 Output shaft 23 Output shaft 24 switching device 25 coupling element 26 Gearing 27 Gearing 28 Gearing 29 Drive unit 30 automotive transmissions 31 Wave 32 drive unit 33 automotive transmissions 34 Drive unit 35 automotive transmissions 36 Differential lock 37 electric vehicles 38 vehicle axle 39 Motor vehicle drive axle 40 drive wheel 41 Drive wheel 42 drive unit P1 stepped planetary gear set P2 planetary gear set E11 First element of stepped planetary gear set E21 Second element stepped planetary gear set E31 Third element stepped planetary gear set E41 Fourth element stepped planetary gear set E12 First element planetary gear set E22 Second element planetary gear set E32 Third element planetary gear set A switching element B switching element P Parking lock element G1 first course G2 second gear QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] DE 10 2021 208 564 B3

[0003]

Claims

[1] Motor vehicle transmission (3; 30; 33; 35) for an at least partially electrically driven motor vehicle, - comprising a drive shaft (6) which is provided for a drive-effective connection with at least one drive machine, preferably at least one electric machine (2), an output shaft (7) and a stepped planetary gear set (P1) which has a first element (E11), a second element (E21), a third element (E31) and a fourth element (E41) in the form of a sun gear (11), a planet carrier (8), a ring gear (9) and either a further sun gear or a further ring gear (10), - wherein the planet carrier (8) of the stepped planetary gear set (P1) rotatably supports at least one stepped planetary gear (12) which meshes with the sun gear (11), the ring gear (9) and either the further sun gear or the further ring gear (10), - wherein the fourth element (E41) of the stepped planetary gear set (P1) is connected in a rotationally fixed manner to the drive shaft (6), whereas the first element (E11) of the stepped planetary gear set (P1) is fixed to a housing-fixed component (19), - wherein a planetary gear set (P2) is also provided, which has a first element (E12), a second element (E22) and a third element (E32) in the form of a sun gear (15), a ring gear (17) and a planet carrier (16), - wherein the second element (E22) of the planetary gear set (P2) is connected in a rotationally fixed manner to the output shaft (7), whereas the third element (E32) of the planetary gear set (P2) is fixed, - and wherein at least functionally a first switching element (A) and a second switching element (B) are provided, of which the at least functionally provided first switching element (A) in an actuated state connects the second element (E21) of the stepped planetary gear set (P1) in a rotationally fixed manner to the first element (E12) of the planetary gear set (P2), - whereas the at least functionally provided second shift element (B) in an actuated state connects the third element (E31) of the stepped planetary gear set (P1) in a rotationally fixed manner to the first element (E12) of the planetary gear set (P2), characterized by , - that the third element (E32) of the planetary gear set (P2) is connected in a rotationally fixed manner to the first element (E11) of the stepped planetary gear set (P1) and is connected in a rotationally fixed manner to the housing-fixed component (19) via the intermediate, first element (E11) of the stepped planetary gear set (P1). [2] Motor vehicle transmission (3; 30; 33; 35) according to claim 1, characterized by that the first element (E11) of the stepped planetary gear set (P1) is the planet carrier (8) of the stepped planetary gear set (P1), the second element (E21) of the stepped planetary gear set (P1) is the ring gear (9) of the stepped planetary gear set (P1), the third element (E31) of the stepped planetary gear set (P1) is the further ring gear (10) of the stepped planetary gear set (P1) and the fourth element (E41) of the stepped planetary gear set (P1) is the sun gear (11) of the stepped planetary gear set (P1). [3] Motor vehicle transmission (3; 30; 33; 35) according to claim 2, characterized bythat the at least one stepped planetary gear (12) of the stepped planetary gear set (P1) is in tooth engagement with the sun gear (11) of the stepped planetary gear set (P1) and the further ring gear (10) of the stepped planetary gear set (P1) on a respective first toothing (13), wherein the at least one stepped planetary gear (12) of the stepped planetary gear set (P1) also meshes with the ring gear (9) of the stepped planetary gear set (P1) on a respective second toothing (14). [4] Motor vehicle transmission (3; 30; 33; 35) according to one of claims 1 to 3, characterized by that the output shaft (7) is coupled to an input element (20) of a differential gear set (21) which connects the output shaft (7) in a driving manner to two output shafts (22, 23). [5] Motor vehicle transmission (3; 30; 33; 35) according to claim 4 and claim 3, characterized bythat the differential gear set (21) is located axially overlapping with the tooth engagement established between the at least one stepped planetary gear (12) of the stepped planetary gear set (P1) and the ring gear (9) and radially inward of the planet carrier (8) of the stepped planetary gear set (P1). [6] Motor vehicle transmission (3) according to claim 4 or 5, characterized by that the differential gear set (21) is arranged axially overlapping with and radially inward of the planetary gear set (P2). [7] Motor vehicle transmission (35) according to one of claims 4 to 6, characterized by that the differential gear set (21) is assigned a differential lock (36) which, when actuated, connects one of the output shafts (22, 23) in a rotationally fixed manner to the input element (20) or connects the two output shafts (22, 23) in a rotationally fixed manner to one another. [8] Motor vehicle transmission (3; 30; 33; 35) according to one of the preceding claims, characterized byin that the first shifting element (A) and the second shifting element (B) are formed by a common shifting device (24) which has a coupling element (25), wherein the coupling element (25) can be transferred into a first shifting state and into a second shifting state, wherein the coupling element (25) in its first shifting state functionally represents an actuated state of the first shifting element (A) and connects the second element (E21) of the stepped planetary gear set (P1) in a rotationally fixed manner to the first element (E12) of the planetary gear set (P2), and wherein the coupling element (25) in its second shifting state functionally represents an actuated state of the second shifting element (B) and connects the third element (E31) of the stepped planetary gear set (P1) in a rotationally fixed manner to the first element (E12) of the planetary gear set (P2). [9] Motor vehicle transmission (3; 30; 33; 35) according to claim 8, characterized byin that the coupling element (25) is guided in a rotationally fixed manner in its two switching states and during an axial displacement between its two switching states on a first toothing (26) which is connected in a rotationally fixed manner to the first element (E12) of the planetary gear set (P2), wherein the coupling element (25) in its first switching state, with existing tooth engagement with the first toothing (26), additionally engages in a second toothing (27) which is connected in a rotationally fixed manner to the second element (E21) of the stepped planetary gear set (P1), and wherein the coupling element (25) in its second switching state, with existing tooth engagement with the first toothing (26), additionally engages in a third toothing (28) which is connected in a rotationally fixed manner to the third element (E31) of the stepped planetary gear set (P1). [10] Motor vehicle transmission (30; 33; 35) according to one of the preceding claims, characterized bythat a parking lock element (P) is also provided which, in an actuated state, directly or indirectly locks the output shaft (7). [11] Motor vehicle transmission (30; 33; 35) according to claim 10, characterized by that the parking lock element (P) is arranged in the power flow between two (E12, E32; E12, E22) of the elements (E21, E22, E32) of the planetary gear set (P2) and, in an actuated state, connects these two elements (E12, E32; E12, E22) of the planetary gear set (P2) to one another in a rotationally fixed manner. [12] Motor vehicle transmission (30; 33; 35) according to claim 11, characterized by that the parking lock element (P) in an actuated state fixes the first element (E12) or the second element (E22) of the planetary gear set (P2). [13] Motor vehicle transmission (30; 33; 35) according to one of claims 10 to 12, characterized bythat the parking lock element (P) is arranged axially overlapping and radially surrounding the planetary gear set (P2) or is placed axially on a side of the planetary gear set (P2) axially facing away from the stepped planetary gear set (P1). [14] Motor vehicle transmission (3) according to one of the preceding claims, characterized bythat the third element (E32) of the planetary gear set (P2) is the sun gear (15) of the planetary gear set (P2), whereas the second element (E22) of the planetary gear set (P2) is the planet carrier (16) of the planetary gear set (P2) when the planetary gear set (P2) is designed as a minus planetary set and the ring gear of the planetary gear set when the planetary gear set is designed as a plus planetary set, and wherein the first element (E12) of the planetary gear set (P2) is the ring gear (17) of the planetary gear set (P2) when the planetary gear set (P2) is designed as a minus planetary set and the planet carrier of the planetary gear set when the planetary gear set is designed as a plus planetary set. [15] Motor vehicle transmission (30; 33; 35) according to one of the preceding claims, characterized bythat the first element (E12) of the planetary gear set (P2) is the sun gear (15) of the planetary gear set (P2), whereas the second element (E22) of the planetary gear set (P2) is the planet carrier (16) of the planetary gear set (P2) when the planetary gear set (P2) is designed as a minus planetary set and the ring gear of the planetary gear set when the planetary gear set is designed as a plus planetary set, and wherein the third element (E32) of the planetary gear set (P2) is the ring gear (17) of the planetary gear set (P2) when the planetary gear set (P2) is designed as a minus planetary set and the planet carrier of the planetary gear set when the planetary gear set is designed as a plus planetary set. [16] Drive unit (1; 29; 32; 34) for an at least partially electrically driven motor vehicle, comprising at least one electric machine (2) and a motor vehicle transmission (3; 30; 33; 35) according to one or more of claims 1 to 15, wherein a respective rotor (5) of the at least one electric machine (2) is coupled to the drive shaft (6) of the motor vehicle transmission (3; 30; 33; 35). [17] Drive unit (1; 29; 32; 34) according to claim 16, characterized by that the stepped planetary gear set (P1) of the motor vehicle transmission (3; 30; 33; 35) is placed axially between the at least one electric machine (2) and the planetary gear set (P2) of the motor vehicle transmission (3; 30; 33; 35). [18] Electrically driven motor vehicle drive axle (39) for an at least partially electrically driven motor vehicle, comprising a drive unit (42) according to claim 16 or 17. [19] Hybrid or electric vehicle (37) comprising a drive unit (1; 29; 32; 34) according to claim 16 or 17 or a motor vehicle drive axle (39) according to claim 18. [20] Method for operating a motor vehicle transmission (3; 30; 33; 35) according to one or more of claims 1 to 15, - wherein a first gear (G1) is switched between the drive shaft (6) and the output shaft (7) by representing an actuated state of the first switching element (A), - and wherein a second gear (G2) is switched between the drive shaft (6) and the output shaft (7) by representing an actuated state of the second switching element (B).

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