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, the motor vehicle transmission is provided, at least functionally, with a first shifting element (A), a second shifting element (B), a third shifting element (C), and a fourth shifting element (D).

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 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 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,and wherein at least functionally, a first shifting element and a second shifting element are provided, of which the at least functionally provided first shifting element, in an actuated state, locks the second element of the stepped planetary gear set, whereas the at least functionally provided second shifting element, in an actuated state, locks the third element of the stepped planetary gear set. Furthermore, the invention relates to a drive unit for an at least partially electrically powered motor vehicle, an electrically drivable motor vehicle drive axle for an at least partially electrically powered motor vehicle, a hybrid or electric vehicle, and a method for operating a motor vehicle transmission.

[0002] In electric and hybrid vehicles, a motor vehicle transmission is sometimes provided in the respective drive train 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 11 2011 104 355 T5 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, has a stepped planetary gear set. The stepped planetary gear set has a planet carrier which rotatably supports at least one stepped planet, wherein the at least one stepped planet 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 is connected in a rotationally fixed manner to an output shaft, which is also connected in a rotationally fixed manner to an input element of the differential gear set. The differential gear set couples the output shaft to two output shafts.Furthermore, a switching device is provided by which the function of two switching elements is represented, wherein the switching device fixes the first ring gear in a first switching state and the second ring gear in a second switching state to a transmission housing.

[0004] Document DE 10 2022 209 071 A1 discloses an electric drive device comprising a single electric machine connected to a shiftable planetary gear set via a transmission input shaft, wherein the planetary gear set has at least a first shifting element for shifting a first gear, a second shifting element for shifting a second gear, a stepped planetary gear set, and a negative planetary gear set with a sun gear shaft, a ring gear shaft fixed to the housing, and a carrier shaft. The stepped planetary gear set has a sun gear shaft connected in a rotationally fixed manner to the transmission input shaft, a first ring gear shaft connected in a rotationally fixed manner to the housing by means of the first shifting element, a second ring gear shaft connected in a rotationally fixed manner to the carrier shaft of the negative planetary gear set by means of the second shifting element, and a carrier shaft accommodating a plurality of stepped planetary gears and connected in a rotationally fixed manner to the sun gear shaft of the negative planetary gear set.The carrier shaft of the negative planetary gear set is connected in a rotationally fixed manner to a transmission output shaft, wherein at least the transmission input shaft, the transmission output shaft and the switchable planetary gear are arranged on a common first rotational axis.

[0005] From the document DE 10 2020 211 067 A1, an electric drive for a vehicle is known, comprising: an electric machine whose rotor is connected to an input shaft of a first planetary gear set, an output shaft arranged coaxially to the input shaft, and three shift elements for engaging gear steps, wherein the first planetary gear set is designed as a stepped planetary transmission whose planet gears, mounted on a planet carrier, have two different effective diameters. A first sun gear of the planetary gear set meshes with the larger effective diameter of the planet gears, and a second sun gear of the planetary gear set meshes with the smaller effective diameter of the planet gears. A ring gear of the planetary gear set meshes with the larger effective diameter. The first sun gear of the planetary gear set is connected in a rotationally fixed manner to the first input shaft.The second sun gear of the planetary gear set is connected to the output shaft in a rotationally fixed manner.

[0006] Based on the prior art described above, it is now the object of the present invention to provide a motor vehicle transmission which is suitable for the integration of a drive motor, and here preferably an electric motor, and via which high gear ratios and a high gear spread can be achieved with this integration.

[0007] This object is achieved starting from 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 14 or 15. Furthermore, claim 16 relates to an electrically drivable motor vehicle drive axle for an at least partially electrically powered motor vehicle, while claim 17 relates to a hybrid or electric vehicle. Finally, claims 18 and 19 each relate to a method for operating a motor vehicle transmission according to the invention.

[0008] According to the invention, a motor vehicle transmission comprises a drive shaft provided for a drive-effective connection to at least one prime mover, 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 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 the further ring gear. In addition, the fourth element of the stepped planetary gear set is connected to the drive shaft in a rotationally fixed manner.In addition, at least functionally, a first shifting element and a second shifting element are provided, of which the at least functionally provided first shifting element fixes the second element of the stepped planetary gear set in an actuated state, whereas the at least functionally provided second shifting element fixes the third element of the stepped planetary gear set in an actuated state.

[0009] 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 force 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 force flow guidance. The respective shaft can 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.

[0010] 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 when the motor vehicle transmission is installed, 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., via 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.

[0011] 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.

[0012] 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.

[0013] 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.

[0014] The stepped planetary gear set of the motor vehicle transmission according to the invention consists of a sun gear, a ring gear, a further sun gear or a further ring gear, and a planet carrier, 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 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 engagement with one sun gear and one ring gear takes place at one toothing, while the tooth engagement 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.

[0015] 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.

[0016] The invention now comprises the technical teaching that 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. The first element of the planetary gear set is connected in a rotationally fixed manner to the first element of the stepped planetary gear set, whereas the second element of the planetary gear set is connected in a rotationally fixed manner to the output shaft. In addition, at least functionally, a third shifting element and a fourth shifting element are provided, of which the at least functionally provided third shifting element fixes the third element of the planetary gear set in an actuated state, whereas the at least functionally provided fourth shifting element connects the third element of the planetary gear set in a rotationally fixed manner to the second element of the stepped planetary gear set in an actuated state.

[0017] In the motor vehicle transmission according to the invention, the fourth element of the stepped planetary gear set is permanently connected in a rotationally fixed manner to the input shaft, so that the input shaft and the fourth element of the stepped planetary gear set always rotate together. Furthermore, there is a rotationally fixed connection between the second element of the planetary gear set and the output shaft, whereby the output shaft and the second element of the planetary gear set also permanently rotate together. The planetary gear set and the stepped planetary gear set are additionally coupled to one another in that the first element of the planetary gear set is permanently connected in a rotationally fixed manner to the first element of the stepped planetary gear set, so that the first element of the planetary gear set and the first element of the stepped planetary gear set permanently rotate together.

[0018] The motor vehicle transmission according to the invention at least functionally comprises a first shifting element, a second shifting element, a third shifting element, and a fourth shifting element. An actuated state of the at least functionally provided first shifting element results in the second element of the stepped planetary gear set becoming locked, whereby the second element of the stepped planetary gear set is then prevented from rotating. The third element of the stepped planetary gear set can also be locked and thus prevented from rotating by implementing the actuated state of the at least functionally provided second shifting element. In the planetary gear set, the third element can, on the one hand, be locked and thus prevented from rotating, for which purpose the actuated state must be implemented in the at least functionally provided third shifting element.On the other hand, the third element of the planetary gear set can also be connected in a rotationally fixed manner to the second element of the stepped planetary gear set by representing the actuated state of the at least functionally provided fourth switching element.

[0019] Such a design of a motor vehicle transmission has the advantage that, through the inventive coupling of the stepped planetary gear set and the planetary gear set to one another 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 motor. This can be achieved with a high gear ratio spread and, at the same time, in a compact installation space, thus resulting in a compact motor vehicle transmission with a high gear ratio and a high gear ratio spread.

[0020] Thus, a first gear can be shifted between the input shaft and the output shaft by displaying the actuated states of both the first shifting element and the third shifting element. In addition, a second gear is displayed between the input shaft and the output shaft by displaying an actuated state of the second shifting element and, at the same time, an actuated state of the third shifting element. A third gear is shifted between the input shaft and the output shaft by displaying the actuated states of both the second shifting element and the fourth shifting element. Within the scope of the invention, however, the first gear in the motor vehicle transmission could also be shifted alternatively between the input shaft and the output shaft by displaying the actuated states of both the first shifting element and the fourth shifting element.

[0021] In the motor vehicle transmission according to the invention, the input shaft and the output shaft are arranged, in particular, 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] In the motor vehicle transmission according to the invention, it is very particularly preferred that exactly four shifting elements are provided, at least functionally, for shifting different gears between the drive shaft and the output shaft, 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 shifting device. A component that represents the function can then combine the function of two shifting elements in one device.

[0024] For the purposes of the invention, a "rotatably fixed" 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] 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 permanently fixed component, 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.

[0026] Within the scope 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 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 within the meaning 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.

[0027] The planetary gear set is composed of a first element, a second element, and a third element, one of these elements being 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 rotatably supports at least one planetary gear, the at least one planetary gear meshing with both the sun gear of the planetary gear set and the ring gear of the planetary gear set. When the planetary gear set is designed as a minus planetary gear set, the first element of the planetary gear set is the sun gear, the second element of the planetary gear set is the planet carrier, and the third element of the planetary gear set is the ring gear. In particular, several planetary gears are rotatably supported in the planet carrier.

[0028] Alternatively, the planetary gear set could also be designed as a positive planetary gear set. In this case, at least one pair of planetary gears is rotatably mounted in the planet carrier of the planetary gear set, of which one planetary gear meshes with the sun gear of the planetary gear set and one planetary gear meshes with the ring gear of the planetary gear set. In addition, the planetary gears of the at least one pair of planetary gears mesh with one another. In contrast to a design as a negative planetary gear set, the first element of the planetary gear set is preferably the sun gear, the second element of the planetary gear set is the ring gear, and the third element of the planetary gear set is the planet carrier. In comparison to a design as a negative planetary gear set, the stationary gear ratio of the planetary gear set must also be increased by one. As already described above, the planetary gear set is preferably a negative planetary gear set.

[0029] 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 another 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.

[0030] 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.

[0031] 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. This advantageously makes it possible to distribute a drive torque generated at the output shaft between the two output shafts, with the differential gear set also being able to compensate for 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.

[0032] 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 gear.Such a bevel gear is also preferably used when the differential gear set is used as a longitudinal differential and the motor vehicle transmission is aligned transversely to the direction of travel.

[0033] 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 and radially inward of the tooth engagement of the at least one stepped planetary gear of the stepped planetary gear set with the ring gear 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 further 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.

[0034] 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 positioned in a first shifting position and a second shifting position, respectively, wherein the coupling element in the first shifting position functionally represents an actuated state of the first shifting element and locks the second element of the stepped planetary gear set, whereas the coupling element in the second shifting position functionally represents an actuated state of the second shifting element and locks the third element of the stepped planetary gear set. This allows the function of the first shifting element and the second shifting element to be represented by one shifting device and thus in a compact manner.Furthermore, to represent the actuated states, only one common actuating mechanism is required, via which the coupling element can be positioned in the respective different switching positions. Preferably, the coupling element can also be positioned in a neutral position between the switching positions, in which neither an actuated state of the first switching element nor an actuated state of the second switching element is represented. Within the scope of the invention, a "switching position" or a "neutral position" can also be an axial adjustment range within which the coupling element is to be positioned in order to realize the respective switching position or the respective neutral position.

[0035] The aforementioned switching device is designed in particular such that the coupling element is guided in a rotationally fixed and axially displaceable manner on a first toothing in the two switching positions and during axial displacement between the two switching positions. The first toothing can be designed on a permanently fixed component, such as a transmission housing, a part of a transmission housing or a component connected thereto in a rotationally fixed manner. In the first switching position, the coupling element then engages with a second toothing which is connected in a rotationally fixed manner to the second element of the stepped planetary gear set. Upon transfer to the second switching position, the coupling element comes into tooth engagement with a third toothing which is connected in a rotationally fixed manner to the third element of the stepped planetary gear set.

[0036] The coupling element of the switching device is in particular in the form of 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 of the switching device are in particular designed as claw teeth, so that the function of unsynchronized claw switching elements is reproduced via the switching device. Alternatively, the first switching element and the second switching element could also be in the form of individual switching elements, wherein the two switching elements in this case are in particular designed as form-fitting 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.

[0037] In a further development of the aforementioned variant of the invention, the first toothing is configured radially surrounding the coupling element, whereas the second toothing and the third toothing are configured radially inward of the coupling element. This allows the switching device forming the first switching element and the second switching element to be realized in an axially compact space.

[0038] Alternatively or in addition to the aforementioned embodiment, the third shifting element and the fourth shifting element are formed by a common shifting device which has a coupling element. This coupling element can be positioned in a first shifting position and in a second shifting position, wherein the coupling element in the first shifting position functionally represents an actuated state of the third shifting element and fixes the third element of the planetary gear set, while the coupling element in the second shifting position functionally represents an actuated state of the fourth shifting element and connects the third element of the planetary gear set in a rotationally fixed manner to the second element of the stepped planetary gear set. This allows a compact design to be realized by implementing the functions of the third shifting element and the fourth shifting element by a common shifting device.Accordingly, only one actuating actuator needs to be provided to represent the actuated states of the two switching elements, via which the coupling element can be positioned in the different switching positions. In particular, the coupling element can be positioned in an intermediate neutral position between the switching positions, in which neither the third switching element nor the fourth switching element is actuated. Here, too, a "switching position" or a "neutral position" within the scope of the invention can be an axial adjustment range within which the coupling element is to be positioned in order to realize the respective switching position or the respective neutral position.

[0039] Preferably, the coupling element of the aforementioned switching device is guided in a rotationally fixed and axially displaceable manner on a first toothing in the two switching positions and during axial displacement between the two switching positions, wherein this first toothing is connected in a rotationally fixed manner to the third element of the planetary gear set. In the first switching position, the coupling element then engages in a second toothing which is fixed, wherein the second toothing can be configured on a permanently fixed component, such as a transmission housing, a part of a transmission housing or a component connected thereto in a rotationally fixed manner. Upon movement into the second switching position, the coupling element comes into tooth engagement with a third toothing which is permanently rotationally fixedly connected to the second element of the stepped planetary gear set.

[0040] The coupling element is preferably designed as a sliding sleeve. In particular, the coupling element also 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 of the switching device are preferably designed as claw teeth, so that the functions of the third switching element and the fourth switching element are represented via the switching device as unsynchronized claw switching elements. Alternatively, the third switching element and the fourth switching element could also be present as individual switching elements, wherein the switching elements in this case are designed in particular as positive-locking switching elements and here particularly preferably as unsynchronized claw switching elements.However, a design as locking synchronizers or as force-locking switching elements is also possible, in particular as multi-disk switching elements.

[0041] In the motor vehicle transmission according to the invention, both of the aforementioned shifting devices are particularly preferably implemented jointly. The second toothing of the shifting device forming the first shifting element and the second shifting element and the third toothing of the shifting device forming the third shifting element and the fourth shifting element can be formed by a common toothing, in which, in addition to individual engagement, a simultaneous engagement of both the coupling element of the shifting device forming the first shifting element and the second shifting element and the coupling element toothing of the shifting device forming the third shifting element and the fourth shifting element can be realized. As a result, the two shifting devices can be arranged axially directly adjacent to one another.The common toothing can be used to represent an enclosing of the coupling element of one switching device, an enclosing of the coupling element of the other switching device or even a simultaneous enclosing of the coupling elements of both switching devices.

[0042] Alternatively, the second toothing of the switching device forming the first switching element and the second switching element and the third toothing of the switching device forming the third switching element and the fourth switching element are formed by a common toothing, into which no simultaneous engagement of the coupling element of the switching device forming the first switching element and the second switching element and the coupling element toothing of the switching device forming the third switching element and the fourth switching element can be represented. As a result, the two switching devices can be arranged axially next to one another in a particularly compact manner, since the common toothing can then be designed to be axially shortened due to the non-simultaneous engagement of the coupling elements.

[0043] However, in the variant described above, the alternative switching of the first gear cannot be realized, in which a simultaneous actuation of both the first switching element and the fourth switching element is carried out.

[0044] In a further development of the invention, the coupling element of the switching device forming the first switching element and the second switching element and the coupling element of the switching device forming the third switching element and the fourth switching element are coupled to a common actuating actuator, via which five positions can be set sequentially. This allows the two switching devices to be actuated jointly via one actuating actuator, which enables a compact arrangement and reduces manufacturing costs. In a first position, the actuating actuator positions the coupling element of the switching device forming the first switching element and the second switching element in its first switching position and the coupling element of the switching device forming the third switching element and the fourth switching element in its first switching position, so that the first gear is engaged.In a second position, the actuator positions the coupling element of the switching device forming the first switching element and the second switching element in a neutral position and the coupling element of the switching device forming the third switching element and the fourth switching element in its first switching position, whereby no gear is engaged. In this neutral position, the gear to be engaged subsequently can then be synchronized, in particular via the drive motor embodied as an electric motor.

[0045] In a third position, the actuating actuator positions the coupling element of the switching device forming the first switching element and the second switching element in its second switching position and the coupling element of the switching device forming the third switching element and the fourth switching element in its first switching position, so that the second gear is engaged. A further neutral shift of the motor vehicle transmission can be achieved by the actuating actuator, in a fourth position, positioning the coupling element of the switching device forming the first switching element and the second switching element in its second switching position and the coupling element of the switching device forming the third switching element and the fourth switching element in a neutral position. Here, too, synchronization of the gear to be shifted subsequently can then be carried out.Finally, in a fifth position, the actuating actuator positions the coupling element of the shifting device forming the first shifting element and the second shifting element in its second shift position and the coupling element of the shifting device forming the third shifting element and the fourth shifting element in its second shift position. This then engages the third gear.

[0046] 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 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. In this case, it is particularly preferable for the drive unit to provide exactly one electric machine in addition to the motor vehicle transmission.

[0047] 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 axially offset 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.

[0048] 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.

[0049] 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 provided 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.

[0050] Within the scope of the invention, the aforementioned 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.

[0051] Advantageous embodiments of the invention, which are explained below, are illustrated in the drawings. It shows: Fig. 1 to 5 are schematic views of a drive unit according to an embodiment of the invention; Fig. 6 an exemplary circuit diagram of a motor vehicle transmission of the drive unit from the Fig. 1 to 5; and Fig. 7 is a schematic view of an electric vehicle according to a preferred embodiment of the invention.

[0052] 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, wherein the electric machine 2 can be operated both as a generator and as an electric motor.

[0053] 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.

[0054] As in Fig. 1, at least one stepped planetary gear 12 is rotatably mounted in the planet carrier 8 of the stepped planetary gear set P1, said stepped planetary 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.

[0055] The planetary gear set P2 has a first element E12, a second element E22, and a third element E32. The first element E12 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 third element E32 of the planetary gear set P2 is a ring gear 17 of the planetary gear set P2. At least one planet 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.

[0056] In this case, the sun gear 11 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 motor 2. In this respect, the sun gear 11 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 sun gear 11 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 motor 2 and / or with the sun gear 11 of the stepped planetary gear set P1.

[0057] The planet carrier 8 of the stepped planetary gear set P1 is permanently connected in a rotationally fixed manner to the sun gear 15 of the planetary gear set P2, so that the planet carrier 8 and the sun gear 15 also constantly run at the same speed. This connection is established via a shaft 19, whereby the shaft 19 could be designed as a single piece with the planet carrier 8 of the stepped planetary gear set P1 and / or with the sun gear 15 of the planetary gear set P2.

[0058] In addition, the planet carrier 16 of the planetary gear set P2 is permanently connected in a rotationally fixed manner to the output shaft 7, whereby the planet carrier 12 could be designed integrally with the output shaft 7. In addition to the planet carrier 16 of the planetary gear set P2, 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.

[0059] The motor vehicle transmission 3 also has two shifting devices 24 and 25. The shifting device 24 is provided with a coupling element 26 in the form of a sliding sleeve, which is guided in a rotationally fixed and axially displaceable manner on a toothing 27 that is rotationally fixedly connected to a permanently fixed component 28. The fixed component 28 is preferably a transmission housing of the motor vehicle transmission 3, a part of such a transmission housing, or a component rotationally fixedly connected thereto. Axial displacements of the coupling element 26 on the toothing 27 can be carried out via an actuating actuator (not shown in detail here), which is preferably designed as an electromechanical actuating actuator.

[0060] The coupling element 26 can be moved axially between two different switching positions via the actuating actuator under constant guidance on the toothing 27, in each of which a tooth engagement of the coupling element 26 is effected with a respective associated toothing 29 or 30. The toothing 29 is connected in a rotationally fixed manner to the ring gear 9 of the stepped planetary gear set P1, while the toothing 30 is connected in a rotationally fixed manner to the ring gear 10 of the stepped planetary gear set P1.

[0061] 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 one of its switching states. Thus, an actuated state of the switching element A is represented in a first, Fig. 1, in which the coupling element 26 engages the toothing 29 and thus connects the ring gear 9 of the stepped planetary gear set P1 in a rotationally fixed manner to the permanently fixed component 28. This accordingly results in the ring gear 9 becoming fixed. From the first switching position, the coupling element 24 can be moved via the actuating actuator into a neutral position in which the coupling element 26 is only in tooth engagement with the toothing 27 and thus no coupling is established via the coupling element 26. In addition to transferring the coupling element 26 into the first switching position, the coupling element 26 can also be moved from the neutral position into a second switching position in which the coupling element 26 is in tooth engagement with the toothing 30.As a result, the coupling element 26 connects the ring gear 10 of the stepped planetary gear set P1 in a rotationally fixed manner to the permanently fixed component 28, which accordingly results in the ring gear 10 being fixed and corresponds to an actuated state of the switching element B.

[0062] The switching device 25 also has a coupling element 31 in the form of a sliding sleeve, wherein the coupling element 31 is guided in a rotationally fixed and axially displaceable manner on a toothing 32 which is rotationally fixedly connected to the ring gear 17 of the planetary gear set P2. From a neutral position, in which the coupling element 31 is only in meshing engagement with the toothing 32, the coupling element 31 can be moved axially into a first, in Fig. 1, in which the coupling element 31 engages in a toothing 33 which is connected in a rotationally fixed manner to the permanently fixed component 28. As a result, the ring gear 17 of the planetary gear set P2 is connected in a rotationally fixed manner to the fixed component 28 in the first switching position of the coupling element 31 and is thus fixed, whereby an actuated state of a switching element C is thereby represented.

[0063] On the other hand, the coupling element 31 can also be moved axially from the neutral position via the associated actuating actuator into a second switching position, in which the coupling element 31 engages with the toothing 29. In the second switching position of the coupling element 31, a rotationally fixed connection is thereby brought about between the ring gear 17 of the planetary gear set P2 and the ring gear 9 of the stepped planetary gear set P1. In this case, the coupling element 31 in the second switching position represents the actuated state of a switching element D. In this respect, the switching device 25 implements the functions of the two switching elements C and D. The toothing 29 is designed to be axially extended on the ring gear 9 in order to enable simultaneous engagement of both the coupling element 26 and the coupling element 31 with the toothing 29.

[0064] In this case, the electric machine 2 is positioned coaxially with 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, the shaft 19, and the differential gear set 21 are also arranged coaxially with 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 and is radially inward of the tooth engagement of the stepped planetary gear 12 with the ring gear 9. This achieves a nested arrangement of the stepped planetary gear set P1 and the differential gear set 21.The shifting devices 24 and 25 are each arranged radially essentially at the same height and surrounding the planetary gear set P1 and the stepped planetary gear set P2, with the toothings 27, 29, 30, 32 and 33 being essentially radially at the same height and being designed radially inward of the coupling elements 26 and 31. The shifting device 25 axially overlaps the stepped planetary gear set P1 and the differential gear set 21, while the shifting device 24 is positioned axially largely in the same plane as the stepped planetary gear set P1. While the output shafts 22 and 23 are designed as solid shafts, the input shaft 6, the output shaft 7 and the shaft 19 are each hollow shafts.

[0065] Furthermore, Fig. 2 a schematic view of a drive unit 34 according to a further embodiment of the invention, this embodiment being largely similar to the previous variant Fig. 1. In contrast to the embodiment according to Fig. 1, in a motor vehicle transmission 35 of the drive unit 34, the toothing 29 on the ring gear 9 of the stepped planetary gear set P1 is axially shortened. Due to this axially shortened design of the toothing 29, the coupling elements 26 and 31 cannot engage simultaneously in the toothing 29, so that in the motor vehicle transmission 35, the actuated states of the shift element A and the shift element D cannot be represented simultaneously. Otherwise, the design option according to Fig. 2 of the variant Fig. 1, so that reference is made to what has been described in this regard.

[0066] Out of Fig. 3 shows a schematic representation of a drive unit 36 ​​according to a further embodiment of the invention. This embodiment essentially corresponds to the preceding variant according to Fig. 2, wherein in contrast to the drive unit 34 from Fig. 2, in a motor vehicle transmission 37 of the drive unit 36, a switching device 38 representing the switching elements A and B is designed differently. Thus, the switching device 38 differs from the switching device 24 of the drive unit 34 from Fig. 2, that a coupling element 39 of the switching device 38 is guided on a toothing 40 in a rotationally fixed and axially displaceable manner, which is rotationally fixedly connected to the permanently fixed component 28 and is designed radially surrounding the coupling element 39 of the switching device 38. In contrast, the toothings 29 and 30 are still radially substantially at the same height as the toothings 32 and 33 and are designed radially inwardly of the coupling element 39. Otherwise, the embodiment according to Fig. 3 according to the variant Fig. 2, so that reference is made to what has been described in this regard.

[0067] Fig. 4 shows a schematic view of a drive unit 41, which is designed according to a further embodiment of the invention and largely corresponds to the previous variant according to Fig. 3. The drive unit 41 differs from the drive unit 36 ​​in that Fig. 3, that in a motor vehicle transmission 42 of the drive unit 41, the planetary gear set P2 is now arranged radially surrounding and axially overlapping with the differential gear set 21. Thus, the differential gear set 21 in the motor vehicle transmission 42 is placed axially overlapping both the tooth engagement of the at least one stepped planetary gear 12 with the ring gear 9, as well as with the planetary gear set P2, wherein the differential gear set 21 is arranged radially inward of the at least one stepped planetary gear 12 and also of the planetary gear set P2. Otherwise, the design option according to Fig. 4 of the variant Fig. 3, so that reference is made to what has been described in this regard.

[0068] Out of Fig. 5 shows a schematic representation of a drive unit 43 which is designed according to a further embodiment of the invention and largely corresponds to the variant according to Fig. 3. In contrast to the variant according to Fig. 3, in a motor vehicle transmission 44 of the drive unit 43, the switching devices 25 and 38 are now a common - in Fig. 5, which is coupled to the two coupling elements 31 and 39, respectively, and can thereby jointly displace the coupling elements 31 and 39 axially on the respectively associated toothing 32 and 40. Accordingly, via the actuating actuator 45, a specific transfer of the coupling elements 31 and 39 between their respective switching positions and thus also a specific actuation of the switching elements A, B, C and D is realized. In order to be able to represent a suitable switching in the motor vehicle transmission 44, the toothings 30, 32 and 33 are each designed to be axially extended. Otherwise, the embodiment according to Fig. 5 of the variant Fig. 3, so that reference is made to what has been described in this regard.

[0069] Fig. 6 shows an exemplary shift diagram of the motor vehicle transmissions 3, 35, 37, 42 and 44 from the Fig. 1 to 5. As can be seen from the exemplary shift diagram, a total of three gears G1, G2, and G3 can be shifted in motor vehicle transmissions 3, 35, 37, 42, and 44. In the columns of the shift diagram, an X indicates which actuated states of the shift elements A, B, C, and D formed by the shift devices 24, 38, and 25 are to be represented in the individual gear.

[0070] As in Fig. 6, a first gear G1 is shifted between the drive shaft 6 and the output shaft 7 by displaying the actuated state of the shift element A in the shifting device 24 or 38 and the actuated state of the shift element C in the shifting device 25. To shift a second gear G2, in addition to displaying an actuated state of the shift element C, the actuated state of the shift element B must also be realized in the shifting device 24 or 38. Finally, a third gear G3 is produced between the drive shaft 6 and the output shaft 7 by displaying the actuated states of the shift element B and the shift element D.

[0071] The first gear G1 can be selected in the motor vehicle transmission 3 from Fig. 1 can also be switched analogously by simultaneously actuating states of the switching element A and the switching element D by simultaneously engaging the coupling element 26 of the switching device 24 and the coupling element 31 of the switching device 25 in the toothing 29.

[0072] In addition, the motor vehicle transmission 44 is made of Fig. 5, a sequential shift of the gears G1, G2 and G3 is carried out via the actuating actuator 45 by moving the actuating actuator 45 to five different positions. In a first position, the actuating actuator 45 positions the coupling element 39 of the switching device 38 in its first switching position, representing the actuated state of the switching element A, and the coupling element 31 of the switching device 25 in its first switching position, representing the actuated state of the switching element C, so that the first gear G1 is shifted. In a second position, the actuating actuator 45 positions the coupling element 31 of the switching device 25 still in its first switching position and the coupling element 39 of the switching device 38 in a neutral position, whereby no gear is shifted. In this case, synchronization of the next gear G2 can be carried out via the electric machine 2.

[0073] In a third position, the actuating actuator 45 still positions the coupling element 31 of the switching device 25 in its first switching position and the coupling element 39 of the switching device 38 in its second switching position, representing the actuated state of the switching element B, so that the second gear G2 is engaged. A further neutral shift of the motor vehicle transmission 44 can be represented by the actuating actuator 45, in a fourth position, positioning the coupling element 31 of the switching device 25 in a neutral position and the coupling element 39 of the switching device 38 still in its second switching position. Finally, in a fifth position, the actuating actuator 45 positions the coupling element 31 of the switching device 25 in its second switching position, representing the actuated state of the switching element D, and the coupling element 39 of the switching device 38 still in its second switching position.This then engages the third gear G3.

[0074] Finally, Fig. 7 shows a schematic view of an electric vehicle 46, which can in particular be an electric commercial vehicle, such as a van. In addition to a steerable, non-driven vehicle axle 47, the electric vehicle 46 also has a motor vehicle drive axle 48 with drive wheels 49 and 50. Part of the motor vehicle drive axle 48 is also the drive unit 51, which corresponds to one of the drive units 1, 34, 36, 41, or 43. The drive wheel 49 is connected in a rotationally fixed manner to the output shaft 22 of the drive unit 51, while the drive wheel 50 is connected in a rotationally fixed manner to the output shaft 23 of the drive unit 51.

[0075] While the vehicle axle 47 is a front axle of the electric vehicle 46, the motor vehicle drive axle 48 is a rear axle of the electric vehicle 46. However, alternatively or in addition to the motor vehicle drive axle 48, the vehicle axle 47 could also be designed as a driven axle with, if necessary, an analogous structure of a drive unit.

[0076] By means of the embodiments according to the invention, a compact motor vehicle transmission with suitable gear ratios for the integration of an electric machine 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 Wave 20 input element 21 Differential gear set 22 Output shaft 23 Output shaft 24 switching device 25 Switching device 26 coupling element 27 Gearing 28 fixed component 29 Gearing 30 gearing 31 coupling element 32 gearing 33 Gearing 34 Drive unit 35 automotive transmissions 36 drive unit 37 motor vehicle transmissions 38 Switching device 39 coupling element 40 gearing 41 Drive unit 42 motor vehicle transmissions 43 Drive unit 44 motor vehicle transmissions 45 Actuator 46 electric vehicles 47 vehicle axle 48 Motor vehicle drive axle 49 Drive wheel 50 drive wheel 51 Drive unit P1 stepped planetary gear set P2 planetary gear set E11 First element of stepped planetary gear set E21 Second element of stepped planetary gear set E31 Third element stepped planetary gear set E41 Fourth element stepped planetary gear set E12 First element of planetary gear set E22 Second element planetary gear set E32 Third element planetary gear set A switching element B switching element C switching element D switching element G1 first course G2 second gear G3 third gear

Claims

[1] Motor vehicle transmission (3; 35; 37; 42; 44) for an at least partially electrically driven motor vehicle, comprising a drive shaft (6) which is provided for a drive-effective connection to 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 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 is in tooth engagement with the sun gear (11), the ring gear (9) and the further ring gear (10), wherein the fourth element (E41) of the stepped planetary gear set (P1) is non-rotatably connected to the drive shaft (6),and wherein at least functionally a first shifting element (A) and a second shifting element (B) are provided, of which the at least functionally provided first shifting element (A) in an actuated state fixes the second element (E21) of the stepped planetary gear set (P1), whereas the at least functionally provided second shifting element (B) in an actuated state fixes the third element (E31) of the stepped planetary gear set (P1), , 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 a 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) - that 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), - that the first element (E12) 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), - that the second element (E22) of the planetary gear set (P2) is connected to the output shaft in a rotationally fixed manner, - and that in addition, at least functionally, a third shifting element (C) and a fourth shifting element (D) are provided, of which the at least functionally provided third shifting element (C) fixes the third element (E32) of the planetary gear set (P2) in an actuated state, whereas the at least functionally provided fourth shifting element (D) in an actuated state connects the third element (E32) of the planetary gear set (P2) in a rotationally fixed manner to the second element (E21) of the stepped planetary gear set (P1). [2] Motor vehicle transmission (3; 35; 37; 42; 44) according to claim 1, 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) at 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) at a respective second toothing (14). [3] Motor vehicle transmission (3; 35; 37; 42; 44) according to one of claims 1 to 2, 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 drivingly effective manner to two output shafts (22, 23). [4] Motor vehicle transmission (3; 35; 37; 42; 44) according to claim 3 and claim 2, characterized bythat the differential gear set (21) is located axially overlapping with the ring gear (9) of the stepped planetary gear set (P1) and radially inside the tooth engagement of the at least one stepped planetary gear (12) of the stepped planetary gear set (P1) with the ring gear (9) of the stepped planetary gear set (P1). [5] Motor vehicle transmission (42) according to claim 3 or 4, characterized by that the differential gear set (21) is arranged axially overlapping with the planetary gear set (P2) and radially inward of the planetary gear set (P2). [6] Motor vehicle transmission (3; 35; 37; 42; 44) 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; 38) which has a coupling element (26; 39), wherein the coupling element (26; 39) can be positioned in a first shift position and in a second shift position, wherein the coupling element (26; 39) in the first shift position functionally represents an actuated state of the first shifting element (A) and fixes the second element (E21) of the stepped planetary gear set (P1), and wherein the coupling element (26; 39) in the second shift position functionally represents an actuated state of the second shifting element (B) and fixes the third element (E31) of the stepped planetary gear set (P1). [7] Motor vehicle transmission (3; 35; 37; 42; 44) according to claim 6, characterized byin that the coupling element (26; 39) is guided in a rotationally fixed and axially displaceable manner in the two switching positions and during an axial displacement between the two switching positions on a first toothing (27; 40) which is fixed, wherein the coupling element (26; 39) in the first switching position engages in a second toothing (29) 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 (26; 39) in the second switching position engages in a third toothing (30) which is connected in a rotationally fixed manner to the third element (E31) of the stepped planetary gear set (P1). [8] Motor vehicle transmission (37; 42; 44) according to claim 7, characterized by that the first toothing (40) is designed radially surrounding the coupling element (39), whereas the second toothing (29) and the third toothing (30) are designed radially inward of the coupling element (39). [9] Motor vehicle transmission (3; 35; 37; 42; 44) according to one of the preceding claims, characterized by in that the third shifting element (C) and the fourth shifting element (D) are formed by a common shifting device (25) which has a coupling element (31), wherein the coupling element (31) can be positioned in a first shifting position and in a second shifting position, wherein the coupling element (31) in the first shifting position functionally represents an actuated state of the third shifting element (C) and fixes the third element (E32) of the planetary gear set (P2), and wherein the coupling element (31) in the second shifting position functionally represents an actuated state of the fourth shifting element (D) and connects the third element (E32) of the planetary gear set (P2) in a rotationally fixed manner to the second element (E21) of the stepped planetary gear set (P1). [10] Motor vehicle transmission (3; 35; 37; 42; 44) according to claim 9, characterized byin that the coupling element (31) is guided in a rotationally fixed and axially displaceable manner in the two switching positions and during an axial displacement between the two switching positions on a first toothing (32) which is connected in a rotationally fixed manner to the third element (E32) of the planetary gear set (P2), wherein the coupling element (31) in the first switching position engages in a second toothing (33) which is fixed, and wherein the coupling element (31) in the second switching position engages in a third toothing (29) which is connected in a rotationally fixed manner to the second element (E21) of the stepped planetary gear set (P1). [11] Motor vehicle transmission (3) according to claim 7 or 8 and according to claim 10, characterized bythat the second toothing (29) of the switching device (24) forming the first switching element (A) and the second switching element (B) and the third toothing (29) of the switching device (25) forming the third switching element (C) and the fourth switching element (D) are formed by a common toothing (29), in which, in addition to an individual engagement, a simultaneous engagement of both the coupling element (26) of the switching device (24) forming the first switching element (A) and the second switching element (B) and the coupling element (31) of the switching device (25) forming the third switching element (C) and the fourth switching element (D) can be represented. [12] Motor vehicle transmission (35; 37; 42; 44) according to claim 7 or 8 and according to claim 10, characterized bythat the second toothing (29) of the switching device (24; 38) forming the first switching element (A) and the second switching element (B) and the third toothing (29) of the switching device (25) forming the third switching element (C) and the fourth switching element (D) are formed by a toothing (29) in which no simultaneous engagement of the coupling element (26; 39) of the switching device (24; 38) forming the first switching element (A) and the second switching element (B) and the coupling element (31) of the switching device (25) forming the third switching element (C) and the fourth switching element (D) can be represented. [13] Motor vehicle transmission (44) according to claim 6 and claim 9, characterized bythat the coupling element (39) of the switching device (38) forming the first switching element (A) and the second switching element (B) and the coupling element (31) of the switching device (25) forming the third switching element (C) and the fourth switching element (D) are coupled to a common actuating actuator (45), via which five positions can be successively set, wherein the actuating actuator (45) - in a first position, the coupling element (39) of the switching device (38) forming the first switching element (A) and the second switching element (B) is positioned in its first switching position and the coupling element (31) of the switching device (25) forming the third switching element (C) and the fourth switching element (D) is positioned in its first switching position, - in a second position, the coupling element (39) of the switching device (38) forming the first switching element (A) and the second switching element (B) is positioned in a neutral position and the coupling element (31) of the switching device (25) forming the third switching element (C) and the fourth switching element (D) is positioned in its first switching position, - in a third position, the coupling element (39) of the switching device (38) forming the first switching element (A) and the second switching element (B) is positioned in its second switching position and the coupling element (31) of the switching device (25) forming the third switching element (C) and the fourth switching element (D) is positioned in its first switching position, - in a fourth position, the coupling element (39) of the switching device (38) forming the first switching element (A) and the second switching element (B) is positioned in its second switching position and the coupling element (31) of the switching device (25) forming the third switching element (C) and the fourth switching element (D) is positioned in a neutral position, - and in a fifth position, the coupling element (39) of the switching device (38) forming the first switching element (A) and the second switching element (B) is positioned in its second switching position and the coupling element (31) of the switching device (25) forming the third switching element (C) and the fourth switching element (D) is positioned in its second switching position. [14] Drive unit (1; 34; 36; 41; 43; 51) for an at least partially electrically driven motor vehicle, comprising at least one electric machine (2) and a motor vehicle transmission (3; 35; 37; 42; 44) according to one or more of claims 1 to 13, 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; 35; 37; 42; 44). [15] Drive unit (1; 34; 36; 41; 43; 51) according to claim 14, characterized by that the stepped planetary gear set (P1) of the motor vehicle transmission (3; 35; 37; 42; 44) is placed axially between the at least one electric machine (2) and the planetary gear set (P2) of the motor vehicle transmission (3; 35; 37; 42; 44). [16] Electrically driven motor vehicle drive axle (48) for an at least partially electrically driven motor vehicle, comprising a drive unit (1; 34; 36; 41; 43; 51) according to claim 14 or 15. [17] Hybrid or electric vehicle (46) comprising a drive unit (1; 34; 36; 41; 43) according to claim 14 or 15 or a motor vehicle drive axle (48) according to claim 16. [18] Method for operating a motor vehicle transmission (3; 35; 37; 42; 44) according to one or more of claims 1 to 13, wherein - wherein a first gear (G1) is shifted between the drive shaft (6) and the output shaft (7) by representing actuated states of both the first shift element (A) and the third shift element (C), - wherein a second gear (G2) is switched between the drive shaft (6) and the output shaft (7) by representing actuated states of both the second switching element (B) and the third switching element (C), - and wherein a third gear (G3) is switched between the input shaft (6) and the output shaft (7) by representing actuated states of both the second switching element (B) and the fourth switching element (C). [19] Method according to claim 18, characterized by that the first gear (G1) between the drive shaft (6) and the output shaft (7) is switched alternatively by representing actuated states of both the first switching element (A) and the fourth switching element (D).

Images