Motor vehicle transmission for a motor vehicle that is at least partially electrically powered

Abstract

The invention relates to a motor vehicle transmission (3) comprising a drive shaft (6), an output shaft (7) and a stepped planetary gear set (P1), which has a first element (E11), a second element (E21) and a third element (E31) in the form of a sun gear (10), a planet carrier (8) and a ring gear (9), wherein the planet carrier (8) of the stepped planetary gear set (P1) rotatably mounts at least one stepped planetary gear (11), which is in tooth mesh with the sun gear (10) of the stepped planetary gear set (P1) at a first toothing (13) and with the ring gear (9) of the stepped planetary gear set (P1) at a second toothing (12), wherein the third element (E31) of the stepped planetary gear set (P1) is rotationally fixed to the drive shaft (6), whereas the first element (E11) of the stepped planetary gear set (P1) is connected to the output shaft (7) in a rotationally fixed manner.Furthermore, a planetary gear set (P2) is provided, which has a first element (E12), a second element (E22) and a third element (E32) in the form of a sun gear (14), a ring gear (16) and a planet carrier (15), wherein the first element (E12) of the planetary gear set (P2) is rotationally fixed to the second element (E21) of the stepped planetary gear set (P1), wherein the second element (E22) of the planetary gear set (P2) is fixed, and wherein the third element (E32) of the planetary gear set (P2) is rotationally fixed to the output shaft (7).

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 with 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 and a third element in the form of a sun gear, a planet carrier and a ring gear, wherein the planet carrier of the stepped planetary gear set rotatably supports at least one stepped planetary gear, which is in tooth engagement with the sun gear at a respective first toothing and with the ring gear at a respective second toothing, wherein 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 and the third element of the stepped planetary gear set is the sun gear of the stepped planetary gear set, wherein a planetary gear set is also provided which has a first element, a second element and a third element in the form of a sun gear, a ring gear and a planet carrier, and wherein the first element of the planetary gear set is the sun gear of the planetary gear set, whereas the second element of the planetary gear set is the planet carrier of the planetary gear set when the planetary gear set is designed as a minus planetary gear set and the ring gear of the planetary gear set when the planetary gear set is designed as a plus planetary gear set,and wherein the third element of the planetary gear set is the ring gear of the planetary gear set when the planetary gear set is designed as a negative planetary gear set, and the planet carrier of the planetary gear set when the planetary gear set is designed as a positive planetary gear set. Furthermore, the invention relates to a drive unit for an at least partially electrically driven motor vehicle, an electrically driven motor vehicle drive axle for an at least partially electrically driven motor vehicle, a hybrid or electric vehicle, and a method for operating a motor vehicle transmission.

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

[0003] DE 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 guides at least one stepped planetary gear, wherein the at least one stepped planetary gear meshes with a sun gear and a first ring gear at a first toothing and meshes with a second ring gear at a second toothing. While the sun gear is connected in a rotationally fixed manner to the drive shaft, the planet carrier 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] Furthermore, DE 10 2017 104 019 B3 discloses a motor vehicle transmission comprising a stepped planetary gear set and another planetary gear set. The planetary gear set distributes power in the power flow from a drive shaft to an output shaft, while the stepped planetary gear set combines power to the output shaft.

[0005] Starting from the prior art described above, it is now the object of the present invention to provide an alternative embodiment of a motor vehicle transmission which is suitable for the integration of a drive machine, and here preferably an electric machine, and via which a high gear ratio can be represented with this integration.

[0006] This object is achieved based on the preamble of claim 1 in conjunction with its characterizing features. The dependent claims that follow therefrom each represent advantageous developments of the invention. A drive unit in which a motor vehicle transmission according to the invention is provided is further the subject of claims 12 to 14. Furthermore, claim 15 relates to an electrically driven motor vehicle drive axle for an at least partially electrically driven motor vehicle, while claim 16 relates to a hybrid or electric vehicle.

[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, and a third element in the form of a sun gear, a planet carrier, and a ring gear. The planet carrier of the stepped planetary gear set rotatably supports at least one stepped planetary gear, which meshes at a first toothing with the sun gear of the stepped planetary gear set and at a second toothing with the ring gear of the stepped planetary gear set. Furthermore, the third element of the stepped planetary gear set is connected in a rotationally fixed manner to the drive shaft, whereas the first element of the stepped planetary gear set is connected in a rotationally fixed manner to the output shaft.

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

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

[0010] The coupling between the at least one drive motor and the drive shaft is preferably in such a way that, in the installed state of the motor vehicle transmission and when the coupling is established, a fixed speed ratio always prevails between a speed of the drive shaft of the motor vehicle transmission and a speed of the drive motor. Thus, within the scope of the invention, at least one further transmission stage, such as a spur gear stage and / or a planetary gear stage, can be provided between the drive shaft and the drive motor, via which a pre-transmission of a rotary movement of the drive motor to the drive shaft can be realized. However, the drive shaft preferably serves as a rotationally fixed connection to the at least one drive motor.

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

[0012] In the motor vehicle transmission according to the invention, the output shaft is provided, in particular, to establish an output-side coupling of the motor vehicle transmission to components which, when the motor vehicle transmission is installed, follow the motor vehicle transmission in the direction of power flow to the drive wheels of the respective motor vehicle. Accordingly, the motor vehicle transmission according to the invention is, in particular, a drive transmission via which a coupling of the at least one drive motor connected to the drive shaft to the drive wheels of the respective motor vehicle can be established in order to transmit a drive movement generated by the drive motor to the drive wheels with different transmission ratios.

[0013] The stepped planetary gear set of the motor vehicle transmission according to the invention consists of a sun gear, a ring gear, and a planet carrier, with at least one stepped planetary gear rotatably mounted in the planet carrier. The stepped planetary gear set thus comprises three elements: a sun gear, a ring gear, and a planet carrier. 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, and the third element of the stepped planetary gear set is the sun gear of the stepped planetary gear set.The at least one stepped planetary gear meshes with the sun gear and the ring gear, respectively. For this purpose, the at least one stepped planetary gear is equipped with two axially adjacent toothings, one of which meshes with the sun gear, while the other meshes with the ring gear. Preferably, the toothings are designed differently and, in particular, are configured with different numbers of teeth at different diameters of the stepped planetary gear.

[0014] Within the scope of the invention, the 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 the sun gear, while the other spur gear has the other toothing on an outer circumference and meshes with the ring gear.

[0015] 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 as a planet carrier, and one as a ring gear. The planetary gear set is preferably a minus planetary gear set, in which the planet carrier guides at least one planet gear in a rotatable manner, the at least one planet gear meshing with both the sun gear of the planetary gear set and the ring gear of the planetary gear set. In particular, a plurality of planet gears are rotatably guided in the planet carrier. The first element of the planetary gear set is then 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.

[0016] 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 each other. In this case, the first element of the planetary gear set is 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. Compared to a design as a negative planetary gear set, the stationary gear ratio of the planetary gear set must also be increased by one. However, the planetary gear set is preferably a negative planetary gear set.

[0017] The invention 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 rotationally fixedly connected to the second element of the stepped planetary gear set, whereas the second element of the planetary gear set is fixed. Furthermore, the third element of the planetary gear set is rotationally fixedly connected to the output shaft.

[0018] In the motor vehicle transmission according to the invention, the third 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 third element of the stepped planetary gear set always rotate together. Furthermore, there is a rotationally fixed connection between the first element of the stepped planetary gear set and the output shaft, whereby the output shaft and the first element of the stepped planetary gear set also permanently rotate together. The planetary gear set and the stepped planetary gear set are also coupled to one another in that the first element of the planetary gear set is permanently connected in a rotationally fixed manner to the second element of the stepped planetary gear set, so that the first element of the planetary gear set and the second element of the stepped planetary gear set permanently rotate together.Furthermore, the third element of the planetary gear set is permanently connected to the output shaft in a rotationally fixed manner. Due to the permanently rotationally fixed connection of the output shaft to the first element of the stepped planetary gear set, this also results in a permanently rotationally fixed connection between the third element of the planetary gear set and the first element of the stepped planetary gear set. Furthermore, the second element of the planetary gear set is permanently fixed and thus permanently prevented from rotating.

[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, a high gear ratio can be achieved, which is 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 a high gear ratio.

[0020] In the motor vehicle transmission according to the invention, the input shaft and the output shaft are arranged coaxially to one another, with the stepped planetary gear set and the planetary gear set also preferably being positioned coaxially to the input shaft and the output shaft. This allows for a particularly compact design of the motor vehicle transmission in the radial direction.

[0021] 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.

[0022] For the purposes of the invention, a "torsion-proof" connection of transmission components means that these components, which are connected or in a rotationally fixed relationship, are rigidly connected to one another and thus always have the same rotational speed. The components, which are connected or in a rotationally fixed relationship, can be separate components that are fastened to one another. Alternatively, components, which are connected or in a rotationally fixed relationship, can also be designed as a single piece and thus form a single component. This is particularly true when these components are arranged spatially close to one another.

[0023] 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 stationary 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. In the present case, the second element of the planetary gear set is permanently connected to the stationary component in a rotationally fixed manner, although a one-piece design of the second element of the planetary gear set with the stationary component would also be conceivable.

[0024] According to one embodiment of the invention, the planetary gear set is arranged axially overlapping and radially surrounding 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 results in a nested arrangement of the stepped planetary gear set and the planetary gear set, thereby achieving an axially compact design of the motor vehicle transmission. Particularly preferably, the ring gear of the stepped planetary gear set and the sun gear of the planetary gear set are designed as a single piece, in particular by providing a component on an inner circumference with internal teeth defining the ring gear of the stepped planetary gear set and on an outer circumference with external teeth forming the sun gear of the planetary gear set.

[0025] According to one possible embodiment of the invention, the output shaft is coupled to an input element of a differential gear set, which drive-effectively connects the output shaft to two output shafts. Advantageously, this allows a drive torque generated at the output shaft to be distributed between the two output shafts, with the differential gear set also being able to equalize the speed between the output shafts. The differential gear set functions in particular as a transverse differential and is preferably designed in the manner of a bevel gear differential. The transverse differential thus formed is preferably used to distribute a drive movement transmitted to the output shaft of the motor vehicle transmission to the output shafts, which are preferably assigned to a motor vehicle drive axle.However, the differential gear set can also function as a longitudinal differential, which can be used to distribute drive power across multiple drive axles. As an alternative to a bevel gear differential, the differential gear set can also be designed as a planetary gear differential, a spur gear differential, etc., within the scope of the invention.

[0026] The input element to which the output shaft is coupled is preferably a differential cage of the differential gear set. When the differential gear set is used as a transverse differential and the motor vehicle transmission is installed transversely to a direction of travel of the associated motor vehicle, the output shaft is then preferably connected to the input element in a rotationally fixed manner. This is also achieved in particular when the differential gear set functions as a longitudinal differential and the motor vehicle transmission is aligned in the direction of travel of the motor vehicle. When the motor vehicle transmission is installed in the direction of travel and the differential gear set is used as a transverse differential, the output shaft is coupled to the input element via a bevel drive.Such a bevel drive is also preferably used when the differential gear set is provided as a longitudinal differential and the motor vehicle transmission is aligned transversely to the direction of travel.

[0027] Preferably, the differential gear set is then arranged axially overlapping and radially inwardly 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, wherein the differential gear set at least partially axially overlaps 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 inwardly of the planetary gear set, which likewise allows a reduction in the axial length of the motor vehicle transmission.

[0028] In a further embodiment of the invention, a parking lock element is also provided, which, in an actuated state, directly or indirectly locks the output shaft. This advantageously allows a parking lock function to be implemented in the motor vehicle transmission according to the invention by actuating the parking lock element. Upon activation of the parking lock function, the output shaft is locked, thereby reliably preventing a motor vehicle having the motor vehicle transmission according to the invention from rolling away.

[0029] Within the scope of the invention, the parking lock element can, when actuated, directly connect the output shaft in a rotationally fixed manner to a permanently fixed component. However, the parking lock element is particularly preferably arranged in the power flow between two of the elements of the planetary gear set and, when actuated, connects these two elements of the planetary gear set to one another in a rotationally fixed manner. As a result, when actuated, the parking lock element causes the planetary gear set to lock, which, due to the permanently rotationally fixed connection of the output shaft to the third element of the planetary gear set and the constantly fixed state of the second element of the planetary gear set, also results in the output shaft becoming locked. The advantage here is that the parking lock element can be made smaller with this arrangement, since the intermediate connection of the planetary gear set means that a lower torque is applied than with a direct connection to the output shaft.The parking lock element can be arranged in the power flow between the first element and the second element of the planetary gear set, the first element and the third element of the planetary gear set or the second element and the third element of the planetary gear set.

[0030] The parking lock element can be arranged axially between the stepped planetary gear set and the planetary gear set, with the parking lock element then being positioned axially overlapping and radially surrounding the differential gear set. This enables an axially compact arrangement.

[0031] Alternatively, the parking lock element can also be arranged between two elements of the stepped planetary gear set in the power flow and, when actuated, connect these two elements of the stepped planetary gear set to each other in a rotationally fixed manner. This results in the stepped planetary gear set and thus also the planetary gear set becoming locked, which again causes the output shaft to seize. In this case, too, the parking lock element is subjected to a lower torque than with a direct connection to the output shaft, allowing the parking lock element to be smaller.

[0032] Preferably, the parking lock element is positioned axially overlapping and radially surrounding the tooth engagement of the at least one stepped planetary gear of the stepped planetary gear set with the sun gear of the stepped planetary gear set. This again enables an axially compact arrangement of the parking lock element. This is particularly achieved when the parking lock element connects the ring gear of the stepped planetary gear set with the sun gear or with the planet carrier upon actuation.

[0033] The parking lock element is, in particular, a switching element that serves to directly or indirectly lock the output shaft. The parking lock element is preferably a positive-locking switching element, particularly a claw-type switching element, although the parking lock element could equally well be designed as a non-positive switching element.

[0034] The invention also relates to a drive unit which, in addition to at least one electric machine, has a motor vehicle transmission according to one or more of the variants described above. In this case, a rotor of each of the at least one electric machine is coupled to the drive shaft of the motor vehicle transmission. The at least one electric machine can, within the scope of the invention, be operated in particular both as a generator and as an electric motor. This makes it possible to create a drive unit which is suitable for use in a motor vehicle in the form of an electric or hybrid vehicle. In this case, it is particularly preferable for the drive unit to provide exactly one electric machine in addition to the motor vehicle transmission.

[0035] The at least one electric machine is preferably connected in a rotationally fixed manner to the drive shaft of the motor vehicle transmission, wherein the at least one electric machine is then arranged coaxially to the drive shaft. As a result, the drive shaft and the respective rotor of the at least one electric machine run at the same speed during operation. Alternatively, it is also conceivable for the respective rotor of the at least one electric machine to be connected in a rotationally fixed manner to an intermediate shaft of the motor vehicle transmission, which is coupled to the drive shaft via at least one gear ratio, so that the at least one electric machine is then possibly offset axially from the drive shaft. Depending on the design of the at least one gear ratio, a coaxial arrangement of the at least one electric machine to the drive shaft is also possible.

[0036] Preferably, the stepped planetary gear set of the motor vehicle transmission is positioned axially adjacent to the at least one electric motor. This allows for a suitable design of a drive unit. An arrangement is also feasible in which the stepped planetary gear set of the motor vehicle transmission, with the tooth engagement of the at least one stepped planetary gear of the stepped planetary gear set with the sun gear of the stepped planetary gear set, is positioned axially overlapping and radially inward of the at least one electric motor. Thus, a partially nested arrangement of the motor vehicle transmission with the electric motor can be realized.

[0037] A drive unit designed according to one of the aforementioned variants is, in particular, part of an electrically driven motor vehicle drive axle, which is intended for an electric or hybrid vehicle. The motor vehicle transmission preferably has a differential gear set coupled to the output shaft and thereby coupling the output shaft to output shafts. Each of the output shafts is assigned to a drive wheel of the motor vehicle drive axle.

[0038] Within the scope of the invention, the aforementioned motor vehicle drive axle is provided for a hybrid or electric vehicle, which may be a passenger car or a commercial vehicle. A commercial vehicle may be an at least partially electrically powered van or a light to medium-duty bus or truck.

[0039] Advantageous embodiments of the invention, which are explained below, are illustrated in the drawings. They show: Fig. 1 to 5 each show a schematic representation of a drive unit according to an embodiment of the invention; and Fig. 6 is a schematic view of an electric vehicle according to a preferred embodiment of the invention.

[0040] Out of Fig. Figure 1 shows a schematic view of a drive unit 1 designed according to one embodiment of the invention. This drive unit 1 consists of an electric machine 2 and a motor vehicle transmission 3, which is designed according to one possible embodiment of the invention. The electric machine 2 is formed in a manner known in principle to those skilled in the art by a stator 4 and a rotor 5, whereby the electric machine 2 can be operated both as a generator and as an electric motor.

[0041] The motor vehicle transmission 3 has, in addition to a drive 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, and a third element E31. While the first element E11 of the stepped planetary gear set P1 is a planet carrier 8, the second element E21 of the stepped planetary gear set P1 is a ring gear 9, and the third element E31 of the stepped planetary gear set P1 is a sun gear 10.

[0042] As in Fig. As can be seen in Figure 1, at least one stepped planetary gear 11 is rotatably mounted in the planet carrier 8 of the stepped planetary gear set P1, said gear having two axially adjacent toothings 12 and 13. While toothing 12 engages with the ring gear 9, the at least one stepped planetary gear 11 meshes with the sun gear 10 at the toothing 13.

[0043] 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 14 of the planetary gear set P2, the second element E22 of the planetary gear set P2 is a planet carrier 15 of the planetary gear set P2, and the third element E32 of the planetary gear set P2 is a ring gear 16 of the planetary gear set P2. At least one planetary gear 17 is rotatably mounted in the planet carrier 15, which meshes with both the sun gear 14 and the ring gear 16. In this respect, the planetary gear set P2 is designed as a minus planetary gear set.

[0044] In this case, the sun gear 10 of the stepped planetary gear set P1 is rotationally fixed to the drive shaft 6, which is also rotationally fixed to the rotor 5 of the electric motor 2. Therefore, the sun gear 10 of the stepped planetary gear set P1 and the rotor 5 are also rotationally fixed to one another via the drive shaft 6, whereby the sun gear 10 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 10 of the stepped planetary gear set P1.

[0045] The planet carrier 8 of the stepped planetary gear set P1 is permanently connected to the output shaft 7 in a rotationally fixed manner, so that the planet carrier 8 and the output shaft 7 also constantly run at the same speed. The output shaft 7 is also permanently connected to the ring gear 16 of the planetary gear set P2 in a rotationally fixed manner, so that the ring gear 16 of the planetary gear set P2 and the planet carrier 8 of the stepped planetary gear set P1 always have the same speed. The output shaft 7 could be designed as a single piece with the planet carrier 8 of the stepped planetary gear set P1 and / or with the ring gear 16 of the planetary gear set P2.

[0046] In addition, the ring gear 9 of the stepped planetary gear set P1 is permanently connected in a rotationally fixed manner to the sun gear 14 of the planetary gear set P2, so that the ring gear 9 and the sun gear 14 always rotate together. Furthermore, the planet carrier 15 of the planetary gear set P2 is permanently connected in a rotationally fixed manner to a permanently fixed component 18, which is preferably a transmission housing of the motor vehicle transmission 3, a part of such a transmission housing, or a component connected in a rotationally fixed manner thereto. In this respect, the planet carrier 15 of the planetary gear set P2 is permanently fixed, although the planet carrier 15 could also be formed integrally with the permanently fixed component 18.

[0047] In addition to the planetary carrier 8 of the stepped planetary gear set P1 and the ring gear 16 of the planetary gear set P2, the output shaft 7 is also permanently and non-rotatably connected to an input element 19 in the form of a differential cage of a differential gear set 20. This differential gear set 20 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 individual input element via the output shaft 7 between two output shafts 21 and 22. The differential gear set 20 also enables speed differences between the output shafts 21 and 22.

[0048] In the present case, the electric machine 2 is positioned coaxially to the motor vehicle transmission 3, in which the input shaft 6, the stepped planetary gear set P1 and the planetary gear set P2, the output shaft 7, the output shafts 21 and 22, and the differential gear set 20 are also arranged coaxially to one another. The stepped planetary gear set P1 is arranged axially adjacent to the electric machine 2 and the planetary gear set P2, wherein the stepped planetary gear set P1 and the planetary gear set P2 are arranged in a nested manner, in that the planetary gear set P2 is arranged axially essentially in a plane with the tooth engagement of the at least one stepped planetary gear 11 with the ring gear 9 of the stepped planetary gear set P1 and is located radially surrounding the ring gear 9 of the stepped planetary gear set P1.Due to the spatially dense arrangement and the rotationally fixed connection, the ring gear 9 of the stepped planetary gear set P1 and the sun gear 14 of the planetary gear set P2 are formed integrally by a common component, which forms the ring gear 9 of the stepped planetary gear set P1 on an inner circumference via an internal toothing and the sun gear 14 of the planetary gear set P2 on an outer circumference via an external toothing.

[0049] In addition, the differential gear set 20 is arranged axially overlapping the stepped planetary gear set P1 and the planetary gear set P2. Specifically, the differential gear set 20 is arranged axially overlapping and radially inwardly of the tooth engagement of the at least one stepped planetary gear 11 with the ring gear 9 and also with the planetary gear set P2. This results in a nested arrangement of the stepped planetary gear set P1, the planetary gear set P2, and the differential gear set 20. While the output shafts 21 and 22 are designed as solid shafts, the input shaft 6 and the output shaft 7 are each designed as hollow shafts.

[0050] Furthermore, Fig. 2 a schematic view of a drive unit 23 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 24 of the drive unit 23, the planetary gear set P2 is no longer arranged nested with the stepped planetary gear set P1 and the differential gear set 20, but is located axially on a side of the stepped planetary gear set P1 and the differential gear set 20 facing away from the electric machine 2. The differential gear set 20 is still axially nested with the stepped planetary gear set P1. Due to the axially spaced placement, the ring gear 9 of the stepped planetary gear set P1 and the sun gear 14 of the planetary gear set P2 are connected to one another in a rotationally fixed manner via a shaft 25. The shaft 25 is designed as a hollow shaft and can be designed in one piece with the ring gear 9 of the stepped planetary gear set P1 and / or with the sun gear 14 of the planetary gear set P2. 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.

[0051] Furthermore, Fig. 3 shows a schematic representation of a drive unit 26, which is designed according to a further embodiment of the invention and essentially corresponds to the preceding variant Fig. 2. The drive unit 26 differs from the drive unit 23 in that Fig. 2, that in a motor vehicle transmission 27 of the drive unit 26, a parking lock element P is now additionally provided, in whose actuated state the output shaft 7 is indirectly locked. The parking lock element P is arranged in the power flow between the output shaft 7 and the shaft 25 and, in an actuated state, connects the output shaft 7 and the shaft 25 in a rotationally fixed manner, whereby the sun gear 14 and the ring gear 16 of the planetary gear set P2 are ultimately also connected in a rotationally fixed manner. This results in the planetary gear set P2 becoming blocked, so that the output shaft 7 is also locked due to the permanently locked state of the planet carrier 15 of the planetary gear set P2.

[0052] The parking lock element P is designed here as a positive-locking switching element, whereby the parking lock element P is specifically designed as a claw switching element. The parking lock element is provided axially between the stepped planetary gear set P1 and the planetary gear set P2, whereby the parking lock element P is placed axially overlapping with and radially surrounding the differential gear set 20. Otherwise, the embodiment according to Fig. 3 of the variant Fig. 2, so that reference is made to what has been described therein.

[0053] Fig. 4 shows a schematic view of a drive unit 28 according to a further embodiment of the invention, wherein this drive unit 28 largely corresponds to the previous variant Fig. 3. In contrast to the drive unit 26 according to Fig. 3, in a motor vehicle transmission 29 of the drive unit 28, the parking lock element P is arranged in the power flow between the shaft 25 and the permanently fixed component 18. Accordingly, actuation of the parking lock element P leads to a locking of the shaft 25 and thus also of the sun gear 14 of the planetary gear set P2 on the permanently fixed component 18, which results in a blocking of the planetary gear set P2 and thus also a corresponding locking of the output shaft 7 connected to the ring gear 16. Furthermore, 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.

[0054] In addition, Fig. 5 shows a schematic representation of a drive unit 30 which is designed according to a further embodiment of the invention and also essentially corresponds to the variant according to Fig. 3. In contrast to the variant according to Fig. 3, in a motor vehicle transmission 31 of the drive unit 30, the parking lock element P is now arranged in the power flow between the drive shaft 6 and the shaft 25 and, when actuated, ensures a rotationally fixed connection of the drive shaft 6 to the shaft 25. This also results in a rotationally fixed connection of the sun gear 10 of the stepped planetary gear set P1 to the ring gear 9 of the stepped planetary gear set P1, thus resulting in the stepped planetary gear set P1 becoming locked. Since the planetary gear set P1 is also coupled to the stepped planetary gear set P1 at both its ring gear 16 and its sun gear 14, this also results in the planetary gear set P2 becoming locked, thus again causing the output shaft 7 to become locked.

[0055] The parking lock element P is arranged axially substantially in a plane with the tooth engagement of the at least one stepped planetary gear 11 with the sun gear 10, wherein the parking lock element is positioned radially surrounding the toothing 13 of the stepped planetary gear 11. Consequently, the parking lock element P is arranged in a nested manner with the stepped planetary gear set P1. In addition, the planetary gear set P2 is arranged axially in a nested manner with the differential gear set 20, in that the differential gear set 20 and the planetary gear set P2 are arranged axially overlapping, wherein the differential gear set 20 is arranged radially inward of the planetary gear set P2. This achieves an overall nesting of the differential gear set 20 with the stepped planetary gear set P1 and the planetary gear set P2. 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.

[0056] Finally, Fig. 6 shows a schematic view of an electric vehicle 32, which may in particular be an electric commercial vehicle, such as a van. In addition to a steerable, non-driven vehicle axle 33, the electric vehicle 32 also has a motor vehicle drive axle 34 with drive wheels 35 and 36. Part of the motor vehicle drive axle 34 is also a drive unit 37, which corresponds to one of the drive units 1, 23, 26, 28 or 30 according to the Fig. 1 to 5. The drive wheel 35 is connected in a rotationally fixed manner to the output shaft 21 of the drive unit 37, while the drive wheel 36 is connected in a rotationally fixed manner to the output shaft 22 of the drive unit 37.

[0057] While the vehicle axle 33 is a front axle of the electric vehicle 32, the motor vehicle drive axle 34 is a rear axle of the electric vehicle 32. However, alternatively or in addition to the motor vehicle drive axle 34, the vehicle axle 33 could also be designed as a driven axle with, if appropriate, an analogous structure of a drive unit.

[0058] By means of the embodiments according to the invention, a compact motor vehicle transmission with a suitable gear ratio 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 Sun gear 11 Stepped planetary gear 12 Gearing 13 Gearing 14 Sun gear 15 planet carriers 16 ring gear 17 Planetary gear 18 fixed component 19 Input element 20 differential gear set 21 Output shaft 22 Output shaft 23 Drive unit 24 automotive transmissions 25 Wave 26 Drive unit 27 automotive transmissions 28 Drive unit 29 Automotive transmissions 30 drive unit 31 automotive transmissions 32 electric vehicles 33 vehicle axle 34 Motor vehicle drive axle 35 drive wheel 36 drive wheel 37 Drive unit P1 stepped planetary gear set P2 planetary gear set E11 First element of stepped planetary gear set E21 Second element stepped planetary gear set E31 Third element stepped planetary gear set E41 Fourth element stepped planetary gear set E12 First element planetary gear set E22 Second element planetary gear set E32 Third element planetary gear set P Parking lock element

Claims

[1] Motor vehicle transmission (3; 24; 27; 29; 31) for an at least partially electrically driven motor vehicle, comprising a drive shaft (6) which is provided for a drive-effective connection with at least one drive machine, preferably at least one electric machine (2), an output shaft (7) and a stepped planetary gear set (P1) which has a first element (E11), a second element (E21) and a third element (E31) in the form of a sun gear (10), a planet carrier (8) and a ring gear (9), wherein the planet carrier (8) of the stepped planetary gear set (P1) rotatably supports at least one stepped planetary gear (11), which is in meshing engagement with the sun gear (10) of the stepped planetary gear set (P1) at a respective first toothing (13) and with the ring gear (9) of the stepped planetary gear set (P1) at a respective second toothing (12), wherein the first element (E11) of the stepped planetary gear set (P1) of 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) and the third element (E31) of the stepped planetary gear set (P1) is the sun gear (10) of the stepped planetary gear set (P1), wherein a planetary gear set (P2) is also provided, which has a first element (E12), a second element (E22) and a third element (E32) in the form of a sun gear (14), a ring gear (16) and a planet carrier (15), and wherein the first element (E12) of the planetary gear set (P2) is the sun gear (14) of the planetary gear set (P2), whereas the second element (E22) of the planetary gear set (P2) is the planet carrier (15) of the planetary gear set (P2) when the planetary gear set (P2) is designed as a minus planetary gear set and when the Planetary gear set as a plus planetary gear set, the ring gear of the planetary gear set isand wherein the third element (E32) of the planetary gear set (P2) is the ring gear (16) of the planetary gear set (P2) when the planetary gear set (P2) is designed as a minus planetary gear set, and the planet carrier of the planetary gear set when the planetary gear set is designed as a plus planetary gear set, , characterized by , - that the third element (E31) of the stepped planetary gear set (P1) is connected in a rotationally fixed manner to the drive shaft (6), whereas the first element (E11) of the stepped planetary gear set (P1) is connected in a rotationally fixed manner to the output shaft (7), - that the first element (E12) of the planetary gear set (P2) is connected in a rotationally fixed manner to the second element (E21) of the stepped planetary gear set (P1), - that the second element (E22) of the planetary gear set (P2) is fixed, - and that the third element (E32) of the planetary gear set (P2) is connected in a rotationally fixed manner to the output shaft (7). [2] Motor vehicle transmission (3) according to claim 1, characterized bythat the planetary gear set (P2) is axially overlapping and radially surrounding the tooth engagement of the at least one stepped planetary gear (11) of the stepped planetary gear set (P1) with the ring gear (9) of the stepped planetary gear set (P1). [3] Motor vehicle transmission (3) according to claim 2, characterized by that the ring gear (9) of the stepped planetary gear set (P1) and the sun gear (14) of the planetary gear set (P2) are designed as a single piece. [4] Motor vehicle transmission (3; 24; 27; 29; 31) according to one of the preceding claims, characterized by that the output shaft (7) is coupled to an input element (19) of a differential gear set (20) which connects the output shaft (7) in a driving manner to two output shafts (21, 22). [5] Motor vehicle transmission (3; 24; 27; 29; 31) according to claim 4, characterized bythat the differential gear set (20) is located axially overlapping and radially inward of the tooth engagement of the at least one stepped planetary gear (11) of the stepped planetary gear set (P1) with the ring gear (9) of the stepped planetary gear set (P1). [6] Motor vehicle transmission (3; 31) according to claim 4 or 5, characterized by that the differential gear set (20) is arranged axially overlapping with and radially inward of the planetary gear set (P2). [7] Motor vehicle transmission (27; 29; 31) according to one of the preceding claims, characterized by that a parking lock element (P) is also provided which, in an actuated state, directly or indirectly locks the output shaft (7). [8] Motor vehicle transmission (27; 29) according to claim 7, characterized bythat the parking lock element (P) is arranged in the power flow between two (E12, E32; E12, E22) of the elements (E12, E22, E32) of the planetary gear set (P2) and, in an actuated state, connects these two elements (E12, E32; E12, E22) of the planetary gear set (P2) to one another in a rotationally fixed manner. [9] Motor vehicle transmission (27; 29) according to claim 8 and according to claim 4 or 5, characterized by that the parking lock element (P) is arranged axially overlapping and radially surrounding the differential gear set (20). [10] Motor vehicle transmission (31) according to claim 7, characterized by that the parking lock element (P) is arranged in the power flow between two (E31, E21) of the elements (E11, E21, E31) of the stepped planetary gear set (P1) and, in an actuated state, connects these two elements (E31, E21) of the stepped planetary gear set (P1) to one another in a rotationally fixed manner. [11] Motor vehicle transmission (31) according to claim 10, characterized bythat the parking lock element (P) is located axially overlapping and radially surrounding the tooth engagement of the at least one stepped planetary gear (11) of the stepped planetary gear set (P1) with the sun gear (10) of the stepped planetary gear set (P1). [12] Drive unit (1; 23; 26; 28; 30) for an at least partially electrically driven motor vehicle, comprising at least one electric machine (2) and a motor vehicle transmission (3; 24; 27; 29; 31) according to one or more of claims 1 to 11, 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; 24; 27; 29; 31). [13] Drive unit (1; 23; 26; 28; 30) according to claim 12, characterized by that the stepped planetary gear set (P1) of the motor vehicle transmission (3; 24; 27; 29; 31) is placed axially adjacent to the at least one electric machine (2). [14] Drive unit according to claim 13, characterized bythat the stepped planetary gear set of the motor vehicle transmission is placed with the tooth engagement of the at least one stepped planetary gear of the stepped planetary gear set with the sun gear of the stepped planetary gear set axially overlapping with and radially inwardly lying on the at least one electric machine. [15] Electrically driven motor vehicle drive axle (34) for an at least partially electrically driven motor vehicle, comprising a drive unit (37) according to one of claims 12 to 14. [16] Hybrid or electric vehicle (32) comprising a drive unit (1; 23; 26; 28; 30) according to one of claims 12 to 14 or a motor vehicle drive axle (34) according to claim 15.

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