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 (P2), and a planetary gear set (P1). 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 first element of the stepped planetary gear set is connected in a rotationally fixed manner to the output 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 driven 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 2018 101 267 A1 describes a drive device comprising an electric machine operatively connected to a transmission device via a drive shaft, the transmission device having at least one planetary stage, at least one stepped planetary gear set, and a differential stage. The planetary stage has a planetary gear set with multiple planetary gears, the planetary gears being rotatably arranged on a first planet carrier and meshing with a first sun gear and a first ring gear. The stepped planetary gear set has multiple stepped planetary gears, each stepped planetary gear having a first and a second gear connected to one another in a rotationally fixed manner, and the stepped planetary gears being rotatably arranged on a second planet carrier.The first gear meshes with a second sun gear and a second ring gear, and the second gear meshes with a third ring gear. The drive shaft is rotationally fixedly connected to the first sun gear, the first planet carrier is rotationally fixedly connected to the second sun gear, and the second planet carrier is operatively connected to the differential stage.

[0005] 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 machine, and here preferably an electric machine, and via which high gear ratios and a high gear spread can be achieved with this integration.

[0006] 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 claims 13 to 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.

[0007] 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. Furthermore, the first element of the stepped planetary gear set is connected to the output 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.

[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 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.

[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 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.

[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 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 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.

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

[0016] In the motor vehicle transmission according to the invention, the first element of the stepped planetary gear set is permanently connected in a rotationally fixed manner to the output shaft, so that the output shaft and the first element of the stepped planetary gear set always rotate together. Furthermore, there is a rotationally fixed connection between the first element of the planetary gear set and the drive shaft, whereby the drive shaft and the first 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 second element of the planetary gear set is permanently connected in a rotationally fixed manner to the fourth element of the stepped planetary gear set, so that the second element of the planetary gear set and the fourth element of the stepped planetary gear set permanently rotate together.

[0017] 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 connected in a rotationally fixed manner to the third element of the stepped planetary gear set, for which purpose the actuated state must be realized in the at least functionally provided third shifting element.On the other hand, the third element of the planetary gear set can be connected in a rotationally fixed manner to the first element of the stepped planetary gear set by representing the actuated state of the at least functionally provided fourth switching element.

[0018] 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 and a wide gear ratio spread can be achieved, which are particularly suitable for the integration of a drive motor in the form of an electric motor. At the same time, this can be achieved in a compact installation space, thus resulting in a compact motor vehicle transmission with high gear ratios.

[0019] For example, 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 the actuated state of the first shifting element and, at the same time, the actuated state of the fourth 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 third shifting element. Finally, a fourth gear is shifted between the input shaft and the output shaft by displaying the actuated state of the second shifting element and, at the same time, the actuated state of the fourth shifting element.

[0020] The motor vehicle transmission according to the invention can, on the one hand, be operated with a first shifting sequence, within the scope of which shifting takes place between the first gear and the second gear, as well as between the second gear and the fourth gear. With this shifting sequence, when shifting between the gears, only the state of two shifting elements needs to be changed, whereby a faster shifting process can be achieved with essentially the same gear ratio spread. Thus, when shifting from the first gear to the second gear, only the at least functionally provided third shifting element needs to be opened and subsequently the at least functionally provided fourth shifting element needs to be actuated, whereas when shifting from the second gear to the fourth gear, only the at least functionally provided first shifting element needs to be opened and subsequently the at least functionally provided second shifting element needs to be actuated.

[0021] Alternatively, however, a second shifting sequence can also be selected during operation of the motor vehicle transmission according to the invention, within the scope of which shifting takes place between the first gear and the third gear, and between the third gear and the fourth gear. This is because here too, during the respective gear changes, only states of two of the shifting elements need to be changed, so that a faster shifting sequence can be achieved with the same gear spread. Thus, when shifting from the first gear to the third gear, only the at least functionally provided first shifting element needs to be opened and then the at least functionally provided second shifting element needs to be actuated, whereas when shifting from the third gear to the fourth gear, only the at least functionally provided third shifting element needs to be opened and then the at least functionally provided fourth shifting element needs to be actuated.

[0022] 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.

[0023] 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.

[0024] In the motor vehicle transmission according to the invention, it is 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. 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 or more shifting elements in one device.

[0025] 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.

[0026] 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.

[0027] Within the meaning 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] The aforementioned switching device is designed in particular such that the coupling element of the switching device is guided in a rotationally fixed and axially displaceable manner on a first toothing, which is fixed, 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.

[0037] 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 are preferably designed as claw teeth, so that the switching device reproduces 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 two switching elements in this case are designed in particular 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.

[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 having a coupling element. This coupling element can be positioned in a first shifting position and in a second shifting position, respectively, wherein the coupling element in the first shifting position functionally represents an actuated state of the third shifting element and connects the third element of the planetary gear set in a rotationally fixed manner to the third element of the stepped 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 first element of the stepped planetary gear set.This allows a compact design to be achieved by mapping the functions of the third switching element and the fourth switching element using a common switching 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 implement the respective switching position or the respective neutral position.

[0039] Specifically, the coupling element, which is designed in particular as a sliding sleeve, can be 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 rotationally fixedly connected to the third element of the planetary gear set. In the first switching position, the coupling element then engages with a second toothing, which is rotationally fixedly connected to the third element of the stepped planetary gear set. Upon movement into the second switching position, the coupling element meshes with a third toothing, which is permanently rotationally fixedly connected to the first element of the stepped planetary gear set.

[0040] In particular, the coupling element also has one or more clutch teeth, at 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 designed in particular as claw teeth, so that the functions of the third switching element and the fourth switching element are represented as unsynchronized claw switching elements via the switching device. 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 non-positive switching elements is also conceivable, 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 together. The shifting device forming the third shifting element and the fourth shifting element can be arranged axially overlapping and radially inward of the shifting device forming the first shifting element and the second shifting element. This has the advantage of allowing a nested arrangement of the two shifting devices, thus reducing the axial space requirement.

[0042] Alternatively, the third toothing of the switching device forming the first switching element and the second switching element and the second toothing of the switching device forming the third switching element and the fourth switching element can be formed by a common toothing, in which, in addition to individual engagement, simultaneous engagement of both 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. This allows the two switching devices to be arranged axially directly next to one another. The common toothing can thereby be represented by engagement of the coupling element of one switching device, by engagement of the coupling element of the other switching device, or by simultaneous engagement of the coupling elements of both switching devices.

[0043] Further alternatively, the third toothing of the switching device forming the first switching element and the second switching element and the second 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.

[0044] In the variant described above, however, only three different gears can be shifted between the input shaft and the output shaft, since the actuated states of the second shifting element and the third shifting element cannot be displayed simultaneously. Thus, a first gear is 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. A second gear is created between the input shaft and the output shaft by displaying the actuated states of both the first shifting element and the fourth shifting element. Finally, a third gear can be shifted by displaying the actuated states of both the second shifting element and the fourth shifting element.

[0045] 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 its first switching position and the coupling element of the switching device forming the third switching element and the fourth switching element in a neutral 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.

[0046] 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 first switching position and the coupling element of the switching device forming the third switching element and the fourth switching element in its second 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 a neutral position and the coupling element of the switching device forming the third switching element and the fourth switching element in its second switching 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.

[0047] 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.

[0048] 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.

[0049] Preferably, the planetary gear set of the motor vehicle transmission is positioned axially overlapping and radially inward of the at least one electric motor. This allows a nested arrangement of the at least one electric motor and the planetary gear set to be realized, thus achieving an axially compact arrangement.

[0050] The axial installation space of the drive unit can also be further reduced by arranging the switching device of the motor vehicle transmission forming the third switching element and the fourth switching element axially overlapping the at least one electric machine and the planetary gear set, wherein the switching device forming the third switching element and the fourth switching element is located radially between the at least one electric machine and the planetary gear set.

[0051] 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.

[0052] 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.

[0053] Advantageous embodiments of the invention, which are explained below, are illustrated in the drawings. It shows: Fig. 1 to 3 are schematic views of a drive unit according to an embodiment of the invention; Fig. 4 an exemplary circuit diagram of a respective motor vehicle transmission of the drive units from the Fig. 1 to 3; Fig. 5 and Fig. 6 schematic representations of a drive unit each corresponding to a possible embodiment of the invention; Fig. 7 an exemplary circuit diagram of a respective motor vehicle transmission of the drive units from the Fig. 5 and Fig. 6; and Fig. 8 is a schematic view of an electric vehicle according to a preferred embodiment of the invention.

[0054] Out of Fig. Figure 1 shows a schematic view of a drive unit 1 designed according to a preferred 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.

[0055] The motor vehicle transmission 3 has, in addition to an input shaft 6 and an output shaft 7, a planetary gear set P1 and a stepped planetary gear set P2. The planetary gear set P1 has a first element E11, a second element E21, and a third element E31, of which the first element E11 of the planetary gear set P1 is a sun gear 8 of the planetary gear set P1, the second element E21 of the planetary gear set P1 is a planet carrier 9 of the planetary gear set P1, and the third element E31 of the planetary gear set P1 is a ring gear 10 of the planetary gear set P1. At least one planet gear 11 is rotatably mounted in the planet carrier 9, which planet gear 11 meshes with both the sun gear 8 and the ring gear 10. In this respect, the planetary gear set P1 is designed as a minus planetary gear set.

[0056] The stepped planetary gear set P2 comprises a first element E12, a second element E22, a third element E32, and a fourth element E42. While the first element E12 of the stepped planetary gear set P2 is a planet carrier 12, the second element E22 and the third element E32 are each a ring gear 13 and 14, respectively. The fourth element E42 of the stepped planetary gear set P2, in contrast, is designed as a sun gear 15.

[0057] As in Fig. 1, at least one stepped planetary gear 16 is rotatably mounted in the planet carrier 12 of the stepped planetary gear set P2, said stepped planetary gear having two axially adjacent toothings 17 and 18. While tooth engagements with the sun gear 15 and the ring gear 14 are established at the toothing 17, the at least one stepped planetary gear 16 meshes with the ring gear 13 at the toothing 18.

[0058] In this case, the sun gear 8 of the 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. In this respect, the sun gear 8 of the 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 8 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 8 of the planetary gear set P1.

[0059] The planet carrier 9 of the planetary gear set P1 is permanently connected in a rotationally fixed manner to the sun gear 15 of the stepped planetary gear set P2, so that the planet carrier 9 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 9 of the planetary gear set P1 and / or with the sun gear 15 of the stepped planetary gear set P2.

[0060] Furthermore, the planet carrier 12 of the stepped planetary gear set P2 is permanently connected in a rotationally fixed manner to the output shaft 7, whereby a one-piece design of the planet carrier 12 with the output shaft 7 would be conceivable. In addition to the planet carrier 12 of the stepped 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.

[0061] The motor vehicle transmission 3 also has two shifting devices 24 and 25. The shifting device 24 includes 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 performed via an actuating actuator—not shown here—which is preferably designed as an electromechanical actuating actuator.

[0062] 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 13 of the stepped planetary gear set P2, while the toothing 30 is connected in a rotationally fixed manner to the ring gear 14 of the stepped planetary gear set P2.

[0063] The switching device 24 thereby maps 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. An actuated state of the switching element A is thus realized in a first switching position of the coupling element 26, in which the coupling element 26 engages the toothing 29 and thus connects the ring gear 13 of the stepped planetary gear set P2 in a rotationally fixed manner to the permanently fixed component 28. This accordingly results in the ring gear 13 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, which is shown in . Fig. 1 and in which a tooth engagement of the coupling element 26 with the toothing 30 takes place. As a result, the coupling element 26 connects the ring gear 14 of the stepped planetary gear set P2 in a rotationally fixed manner to the permanently fixed component 28, which accordingly results in a locking of the ring gear 14 and means an actuated state of the switching element B.

[0064] 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 10 of the planetary gear set P1. From a neutral position, the coupling element 31 can be moved axially into a first, in Fig. 1, in which the coupling element 31 engages the toothing 30, which is connected in a rotationally fixed manner to the ring gear 14 of the stepped planetary gear set P2. As a result, the ring gear 10 of the planetary gear set P1 is connected in a rotationally fixed manner to the ring gear 14 of the stepped planetary gear set 2 in the first switching position of the coupling element 31, thereby representing an actuated state of a switching element C. The toothing 30 is designed to be axially extended on the ring gear 14 in order to enable simultaneous engagement of both the coupling element 26 and the coupling element 31 in the toothing 30, as shown in Fig. 1 shown.

[0065] 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 in a toothing 33. This toothing 33 is connected in a rotationally fixed manner to the planet carrier 12 of the stepped planetary gear set P2, so that in the second switching position of the coupling element 31, a rotationally fixed connection of the ring gear 10 of the planetary gear set P1 with the planet carrier 12 of the stepped planetary gear set P2 is brought about. 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.

[0066] In this case, the electric machine 2 is positioned coaxially with the motor vehicle transmission 3, in which the input shaft 6, the planetary gear set P1 and the stepped 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 planetary gear set P1 is arranged axially between the electric machine 2 and the stepped planetary gear set P2, with the differential gear set 21 axially overlapping the stepped planetary gear set P2. Specifically, the differential gear set 21 axially overlaps and is located radially inside the tooth engagement of the stepped planetary gear 16 with the ring gear 13. This achieves a nested arrangement of the stepped planetary gear set P2 and the differential gear set 21.The shifting devices 24 and 25 are each arranged radially at substantially the same height and surrounding the planetary gear set P1 and the stepped planetary gear set P2, with the shifting device 25 axially overlapping the planetary gear set P1 and the stepped planetary gear set P2, while the shifting device 24 is positioned axially largely in the same plane as the stepped planetary gear set P2. 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 designed as hollow shafts.

[0067] 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 planetary gear set P1 is arranged axially overlapping with and radially inward of the electric machine 2. In addition, the switching device 25 is also placed partially axially overlapping with the planetary gear set P1 and the electric machine 2, with the switching device 25 being located radially between the rotor of the electric machine 2 and the planetary gear set P1. This also has the consequence that the switching device 25 is now arranged radially further inward than the switching device 24, wherein in order to establish a rotationally fixed connection with the ring gear 14 of the stepped planetary gear set 2, a toothing 36 is now additionally provided next to the toothing 30, which is rotationally fixedly connected to the toothing 30 and also to the ring gear 14 and is designed radially further inward with respect to the toothing 30.The coupling element 31 of the switching device 25 can then engage in this toothing 36 in the first switching position to represent the actuated state of the switching element C. Otherwise, the design option corresponds to . Fig. 2 of the variant Fig. 1, so that reference is made to what has been described in this regard.

[0068] Out of Fig. 3 shows a schematic representation of a drive unit 37 which is designed according to a further embodiment of the invention and essentially corresponds to the preceding variant Fig. 2. Thus, the planetary gear set P1 and the switching device 25 are also arranged in a nested manner in a motor vehicle transmission 38 of the drive unit 37, whereby this is different from the variant according to Fig. 2 is now realized in such a way that the planetary gear set P1 and the switching device 25 are placed axially overlapping with and radially inward of the switching device 24. For this purpose, the switching device 24 is then no longer arranged axially overlapping with the stepped planetary gear set P2, but is located axially between the electric machine 2 and the stepped planetary gear set P2. Otherwise, the embodiment according to Fig. 3 otherwise according to the variant Fig. 2, so that reference is made to what has been described in this regard.

[0069] In Fig. 4 is an exemplary circuit diagram of the motor vehicle transmissions 3, 35 and 38 from the Fig. 1 to 3 are shown in tabular form. As can be seen, a total of four gears G1 to G4 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, B, C, and D formed by the shift devices 24 and 25 are to be represented in the individual gear. In each of the gears G1 to G4, actuated states are to be represented for two of the shift elements A, B, C, and D.

[0070] As in Fig. 4, 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 switching device 24 and the actuated state of the shifting element C in the switching device 25. To shift a second gear G2, in addition to displaying an actuated state of the shifting element A, the actuated state of the shifting element D must also be realized. A third gear G3 is created between the drive shaft 6 and the output shaft 7 by displaying the actuated states of the shifting element B and the shifting element C. Finally, a fourth gear G4 is shifted between the drive shaft 6 and the output shaft 7 by displaying the actuated state of the shifting element B in the switching device 24 and the actuated state of the shifting element D in the switching device 25.

[0071] Since switching between the second gear G2 and the third gear G3 would result in switching in both switching devices 24 and 25 and thus a correspondingly longer switching duration, one of two possible switching sequences is preferably used in the motor vehicle transmission 3. In a first possible switching sequence, switching takes place between the second gear G2 and the fourth gear G4, thus omitting the third gear G3. In an alternative, second switching sequence, however, switching takes place between the first gear G1 and the third gear G3, omitting the second gear G2. This allows a faster switching sequence to be realized in each case.

[0072] Furthermore, Fig. 5 shows a schematic view of a drive unit 39 according to a further embodiment of the invention. This drive unit 39 largely corresponds to the drive unit 1 of Fig. 1, where in contrast to the variant according to Fig. 1 in a motor vehicle transmission 40 of the drive unit 39, the ring gear 14 of the stepped planetary gear set P2 is equipped with an axially shortened toothing 41 in a rotationally fixed manner, which serves, on the one hand, to engage the coupling element 26 of the switching device 24 and, on the other hand, to engage the coupling element 31 of the switching device 25. Due to the axially shortened design of the toothing 41, the coupling elements 26 and 31 cannot engage simultaneously, so that in the motor vehicle transmission 40, the actuated states of the switching element B and the switching element C cannot be represented simultaneously. Otherwise, the design option according to Fig. 5 of the variant Fig. 1, so that reference is made to what has been described in this regard.

[0073] Out of Fig. 6 shows a schematic representation of a drive unit 42 which is designed according to a further embodiment of the invention and largely corresponds to the previous variant Fig. 5. Thus, in a motor vehicle transmission 43 of the drive unit 42, the toothing 41 connected to the ring gear 14 in a rotationally fixed manner is axially shortened, so that simultaneous engagement of the coupling elements 26 and 31 of the switching devices 24 and 25 cannot take place. In contrast to the variant according to Fig. 5, the switching devices 24 and 25 now have a common - in Fig. 6 partially shown - is assigned to the actuating actuator 44, which is coupled to the two coupling elements 26 and 31, respectively, and can thereby displace the coupling elements 26 and 31 together axially under guidance on the respective toothing 27 and 32, respectively. Accordingly, a specific transfer of the coupling elements 26 and 31 between their respective switching positions and thus also a specific actuation of the switching elements A, B, C and D is realized via the actuating actuator 44. In order to be able to represent a suitable switching in the motor vehicle transmission 43, on the one hand, a toothing 45 connected in a rotationally fixed manner to the ring gear 13 and, on the other hand, a toothing 46 connected in a rotationally fixed manner to the planet carrier 12 are each designed to be axially extended. Otherwise, the embodiment according to Fig. 6 of the variant Fig. 5, so that reference is made to what has been described in this regard.

[0074] Fig. 7 shows an exemplary shift diagram of the motor vehicle transmissions 40 and 43 from the Fig. 5 and Fig. 6. As can be seen from the exemplary shift diagram, a total of three gears G1', G2' and G3' can be shifted in the motor vehicle transmissions 40 and 43. In the columns of the shift diagram, an X is used to indicate which actuated states of the shift elements A, B, C and D formed by the shift devices 24 and 25 are to be represented in the individual gear. In terms of their representation, the gears G1', G2' and G3' correspond to the gears G1, G2 and G4 of the shift diagram according to Fig. 4. Thus, a first gear G1' is shifted in a manner analogous to the first gear G1, a second gear G2' in a manner analogous to the second gear G2, and a third gear G3' in a manner analogous to the fourth gear G4. In this respect, with regard to the individual shift, the Fig. 4 each described reference is made.

[0075] In the motor vehicle transmission 43 from Fig. 6, a successive shift of the gears G1', G2', and G3' is carried out via the actuating actuator 44, which can move to five different positions for this purpose. In a first position, the actuating actuator 44 positions the coupling element 26 of the switching device 24 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 44 still positions the coupling element 26 of the switching device 24 in its first switching position and the coupling element 31 of the switching device 25 in a neutral position, whereby no gear is shifted. In this case, synchronization of the next gear G2' or G1' can be carried out via the electric machine 2.

[0076] In a third position, the actuating actuator 44 positions the coupling element 26 of the switching device 24 in its first switching position and the coupling element 31 of the switching device 25 in its second switching position, representing the actuated state of the switching element D, so that the second gear G2' is engaged. A further neutral shift of the motor vehicle transmission 43 can be represented by the actuating actuator 44, in a fourth position, positioning the coupling element 26 of the switching device 24 in a neutral position and the coupling element 31 of the switching device 25 in its second switching position. Finally, in a fifth position, the actuating actuator 44 positions the coupling element 26 of the switching device 24 in its second switching position, representing the actuated state of the switching element B, and the coupling element 31 of the switching device 25 in its second switching position.This then engages the third gear G3'.

[0077] Finally, Fig. 8 shows a schematic view of an electric vehicle 47, which can in particular be an electric commercial vehicle, such as a van. In addition to a steerable, non-driven vehicle axle 48, the electric vehicle 47 also has a motor vehicle drive axle 49 with drive wheels 50 and 51. Part of the motor vehicle drive axle 49 is also the drive unit 52, which corresponds to one of the drive units 1, 34, 37, 39, or 42. The drive wheel 50 is connected in a rotationally fixed manner to the output shaft 22 of the drive unit 52, while the drive wheel 51 is connected in a rotationally fixed manner to the output shaft 23 of the drive unit 52.

[0078] While the vehicle axle 48 is a front axle of the electric vehicle 47, the motor vehicle drive axle 49 is a rear axle of the electric vehicle 47. However, alternatively or in addition to the motor vehicle drive axle 49, the vehicle axle 48 could also be designed as a driven axle with, if necessary, an analogous structure of a drive unit.

[0079] 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 Sun gear 9 planet carriers 10 ring gear 11 Planetary gear 12 planet carriers 13 ring gear 14 ring gear 15 Sun gear 16 stepped planetary gear 17 Gearing 18 Gearing 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 gearing 37 Drive unit 38 motor vehicle transmissions 39 Drive unit 40 automotive transmissions 41 Gearing 42 drive unit 43 Motor vehicle transmissions 44 Actuator 45 gearing 46 Gearing 47 electric vehicles 48 vehicle axle 49 Motor vehicle drive axle 50 drive wheel 51 Drive wheel 52 drive unit P1 planetary gear set P2 stepped planetary gear set E11 First element of planetary gear set E21 Second element planetary gear set E31 Third element planetary gear set E12 First element of stepped planetary gear set E22 Second element stepped planetary gear set E32 Third element stepped planetary gear set E42 Fourth element stepped planetary gear set A switching element B switching element C switching element D switching element G1 first course G2 second gear G3 third gear G4 fourth gear

Claims

[1] Motor vehicle transmission (3; 35; 38; 40; 43) 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 (P2) which has a first element (E12), a second element (E22), a third element (E32) and a fourth element (E42) in the form of a sun gear (15), a planet carrier (12), a ring gear (13) and a further ring gear (14), wherein the planet carrier (12) of the stepped planetary gear set (P2) rotatably supports at least one stepped planetary gear (16) which is in tooth engagement with the sun gear (15), the ring gear (13) and the further ring gear (14), wherein the first element (E12) of the stepped planetary gear set (P2) is non-rotatably connected to the output shaft (7),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 (E22) of the stepped planetary gear set (P2), whereas the at least functionally provided second shifting element (B) in an actuated state fixes the third element (E32) of the stepped planetary gear set (P2), , characterized by , - that the first element (E12) of the stepped planetary gear set (P2) is the planet carrier (12) of the stepped planetary gear set (P2), the second element (E22) of the stepped planetary gear set (P2) is the ring gear (13) of the stepped planetary gear set (P2), the third element (E32) of the stepped planetary gear set (P2) is a further ring gear (14) of the stepped planetary gear set (P2) and the fourth element (E42) of the stepped planetary gear set (P2) is the sun gear (15) of the stepped planetary gear set (P2), - that a planetary gear set (P1) is also provided, which has a first element (E11), a second element (E21) and a third element (E31) in the form of a sun gear (8), a ring gear (10) and a planet carrier (9), - that the first element (E11) of the planetary gear set (P1) is connected in a rotationally fixed manner to the drive shaft (6), - that the second element (E21) of the planetary gear set (P1) is connected in a rotationally fixed manner to the fourth element (E42) of the stepped planetary gear set (P2), - 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) in an actuated state connects the third element (E31) of the planetary gear set (P1) in a rotationally fixed manner to the third element (E32) of the stepped planetary gear set (P2), whereas the at least functionally provided fourth shifting element (D) in an actuated state connects the third element (E31) of the planetary gear set (P1) in a rotationally fixed manner to the first element (E12) of the stepped planetary gear set (P2). [2] Motor vehicle transmission (3; 35; 38; 40; 43) according to claim 1, characterized bythat the at least one stepped planetary gear (16) of the stepped planetary gear set (P2) is in tooth engagement with the sun gear (15) of the stepped planetary gear set (P2) and the further ring gear (14) of the stepped planetary gear set (P2) on a respective first toothing (17), wherein the at least one stepped planetary gear (16) of the stepped planetary gear set (P2) also meshes with the ring gear (13) of the stepped planetary gear set (P2) on a respective second toothing (18). [3] Motor vehicle transmission (3; 35; 38; 40; 43) 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 driving manner to two output shafts (22, 23). [4] Motor vehicle transmission (3; 35; 38; 40; 43) according to claim 3 and claim 2, characterized bythat the differential gear set (21) is located axially overlapping with the ring gear (13) of the stepped planetary gear set (P2) and radially inward of the tooth engagement of the at least one stepped planetary gear (16) of the stepped planetary gear set (P2) with the ring gear (13) of the stepped planetary gear set (P2). [5] Motor vehicle transmission (3; 35; 38; 40; 43) 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 (26), wherein the coupling element (26) can be positioned in a first shifting position and in a second shifting position, wherein the coupling element (26) in the first shifting position functionally represents an actuated state of the first shifting element (A) and fixes the second element (E22) of the stepped planetary gear set (P2), and wherein the coupling element (26) in the second shifting position functionally represents an actuated state of the second shifting element (B) and fixes the third element (E32) of the stepped planetary gear set (P2). [6] Motor vehicle transmission (3; 35; 38; 40; 43) according to claim 5, characterized byin that the coupling element (26) 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) which is fixed, wherein the coupling element (26) in the first switching position engages in a second toothing (29; 45) which is connected in a rotationally fixed manner to the second element (E22) of the stepped planetary gear set (P2), and wherein the coupling element (26) in the second switching position engages in a third toothing (30; 41) which is connected in a rotationally fixed manner to the third element (E32) of the stepped planetary gear set (P2). [7] Motor vehicle transmission (3; 35; 38; 40; 43) according to one of the preceding claims, characterized byin 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 connects the third element (E31) of the planetary gear set (P1) in a rotationally fixed manner to the third element (E32) of the stepped 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 (E31) of the planetary gear set (P1) in a rotationally fixed manner to the first element (E12) of the stepped planetary gear set (P2). [8] Motor vehicle transmission (3; 35; 38; 40; 43) according to claim 7, 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 (E31) of the planetary gear set (P1), wherein the coupling element (31) in the first switching position engages in a second toothing (30; 36; 41) which is connected in a rotationally fixed manner to the third element (E32) of the stepped planetary gear set (P2), and wherein the coupling element (31) in the second switching position engages in a third toothing (33; 46) which is connected in a rotationally fixed manner to the first element (E12) of the stepped planetary gear set (P2). [9] Motor vehicle transmission (38) according to claim 5 or 6 and according to claim 7 or 8, characterized bythat the switching device (25) forming the third switching element (C) and the fourth switching element (D) is arranged axially overlapping with and radially inwardly of the switching device (24) forming the first switching element (A) and the second switching element (B). [10] Motor vehicle transmission (3) according to claim 6 and claim 8, characterized bythat the third toothing (30) of the switching device (24) forming the first switching element (A) and the second switching element (B) and the second toothing (30) of the switching device (25) forming the third switching element (C) and the fourth switching element (D) are formed by a common toothing (30), 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. [11] Motor vehicle transmission (40; 43) according to claim 6 and claim 8, characterized bythat the third toothing (41) of the switching device (24) forming the first switching element (A) and the second switching element (B) and the second toothing (41) of the switching device (25) forming the third switching element (C) and the fourth switching element (D) are formed by a toothing (41) in which no simultaneous engagement of 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) is possible. [12] Motor vehicle transmission (43) according to claim 5 and claim 7, characterized bythat 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) are coupled to a common actuating actuator (44), via which five positions can be successively set, wherein the actuating actuator (44) - in a first position, the coupling element (26) of the switching device (24) 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 (26) of the switching device (24) 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 a neutral position, - in a third position, the coupling element (26) of the switching device (24) 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 second switching position, - in a fourth position, the coupling element (26) of the switching device (24) 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 second switching position, - and in a fifth position, the coupling element (26) of the switching device (24) 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. [13] Drive unit (1; 34; 37; 39; 42; 52) for an at least partially electrically driven motor vehicle, comprising at least one electric machine (2) and a motor vehicle transmission (3; 35; 38; 40; 43) according to one or more of claims 1 to 12, 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; 38; 40; 43). [14] Drive unit (34) according to claim 13, characterized by that the planetary gear set (P1) of the motor vehicle transmission (35) is placed axially overlapping with and radially inwardly of the at least one electric machine (2). [15] Drive unit (34) according to claim 14 and with a motor vehicle transmission (35) according to claim 7 or 8, characterized bythat the switching device (25) of the motor vehicle transmission (35) forming the third switching element (C) and the fourth switching element (D) is arranged axially overlapping with the at least one electric machine (2) and the planetary gear set (P1), wherein the switching device (25) forming the third switching element (C) and the fourth switching element (D) is located radially between the at least one electric machine (2) and the planetary gear set (P1). [16] Electrically driven motor vehicle drive axle (49) for an at least partially electrically driven motor vehicle, comprising a drive unit (52; 1; 34; 37; 39; 42) according to one of claims 13 to 15. [17] Hybrid or electric vehicle (47) comprising a drive unit (52; 1; 34; 37; 39; 42) according to one of claims 13 to 15 or a motor vehicle drive axle (49) according to claim 16. [18] Method for operating a motor vehicle transmission (3; 35; 38) according to one or more of claims 1 to 10, wherein - wherein a first gear (G1) is switched between the drive shaft (6) and the output shaft (7) by representing actuated states of both the first switching element (A) and the third switching 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 first switching element (A) and the fourth switching element (D), - wherein a third gear (G3) 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 fourth gear (G4) 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 (D). [19] Method for operating a motor vehicle transmission (40; 43) according to claim 11 or 12, wherein - wherein a first gear (G1') is switched between the drive shaft (6) and the output shaft (7) by representing actuated states of both the first switching element (A) and the third switching 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 first switching element (A) and the fourth switching element (D), - 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 (D).

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