Drive unit for a vehicle

Abstract

The invention relates to a drive unit for a vehicle (100), comprising • an electrical machine (EM), • a coaxial differential (DG), • a coaxially arranged manual transmission (SG) with a first planetary gear set (PS1), a second planetary gear set (PS2) and a positive-locking switching unit arranged therebetween with a first switching element (A), a second switching element (B) and a single sliding sleeve (SM) which can be moved axially between exactly three switching positions, and • a coupling shaft (W) for connecting the second planetary gear set (PS2) to the first planetary gear set (PS1) and for receiving the sliding sleeve (SM) in all switching positions, • wherein the first planetary gear set (PS1) is designed as a stepped planetary gear set and has exactly four shafts, namely a first sun shaft (SO1), a first ring gear shaft (HR1), a second ring gear shaft (HR2) and a first carrier shaft (ST1) with several stepped planetary gears, each of which has a first and second non-rotatably connected gear wheel (Z1, Z2), • wherein in the closed state of the first switching element (A) a first gear with a first ratio is engaged, • wherein in the closed state of the second switching element (B) a second gear with a second ratio is engaged.

Description

[0001] The invention relates to a drive unit for a vehicle, wherein the drive unit comprises a single electric motor, a two-speed manual transmission, and a differential. The invention also relates to a vehicle having such a drive unit.

[0002] For example, DE 11 2011 104 355 T5 discloses a drive unit with a multi-speed transmission. The multi-speed transmission comprises a sun gear and at least one high-speed planetary gear continuously meshed with the sun gear and a high-speed ring gear, the high-speed planetary gear rotating around the sun gear. The multi-speed transmission further comprises at least one low-speed planetary gear connected to the high-speed planetary gear and continuously meshed with a low-speed ring gear and a carrier rotatably meshed with the high-speed planetary gear and the low-speed planetary gear, such that either the high-speed planetary gear or the low-speed planetary gear controls the rotation of the carrier.The multi-speed transmission further includes a transmission housing surrounding the high-speed ring gear and the low-speed ring gear and a clutch disposed adjacent to the high-speed ring gear and the low-speed ring gear, the clutch selectively connecting the high-speed ring gear or the low-speed ring gear to the transmission housing.

[0003] The object of the present invention is to provide an alternative drive unit for a vehicle. In particular, the drive unit should be compact and have a higher gear ratio. This object is achieved by a drive unit having the features of independent patent claim 1. Advantageous embodiments are the subject of the dependent claims, the following description, and the figures.

[0004] A drive unit for a vehicle according to the invention comprises an electric machine with a rotor and a stator, a differential arranged coaxially thereto with a differential input shaft and two differential output shafts, a manual transmission arranged coaxially thereto with a first planetary gear set, a second planetary gear set and a positive-locking shift unit arranged therebetween with a first shifting element, a second shifting element and a single sliding sleeve that can be moved axially between exactly three shift positions, and a coupling shaft for connecting the second planetary gear set to the first planetary gear set and for receiving the sliding sleeve in all shift positions, wherein the first planetary gear set is designed as a stepped planetary gear set and has exactly four shafts, namely a first sun gear shaft, a first ring gear shaft, a second ring gear shaft and a first carrier shaft with several stepped planetary gears,each having a first and second non-rotatably connected gear, wherein the first gear meshes with the first sun gear shaft and the first ring gear shaft, wherein the second gear meshes with the second ring gear shaft, wherein the first sun gear shaft is non-rotatably connected to the rotor, wherein the first ring gear shaft is non-rotatably connected to a stationary component, wherein the second planetary gear set has a second sun gear shaft, a third ring gear shaft, a second carrier shaft, and a plurality of planetary gears, wherein the second carrier shaft is non-rotatably connected to the differential input shaft, wherein, in the closed state of the first shifting element, a first gear with a first ratio is engaged, wherein, in the first gear, the second ring gear shaft and the second sun gear shaft are non-rotatably connected, wherein, in the closed state of the second shifting element, a second gear with a second ratio is engaged,In second gear, the first carrier shaft and the coupling shaft are connected in a rotationally fixed manner.

[0005] The sliding sleeve can be moved into each of the three switching positions by means of a single actuator, with the switching unit having two gear positions and a neutral position. In a gear position, the switching elements connect either the second ring gear shaft or the first carrier shaft, i.e. a respective shaft of the stepped planetary gear set, with the coupling shaft, which in turn is rotationally fixedly connected to a shaft of the second planetary gear set. In the neutral position, two shafts are decoupled from each other via the switching unit, with the sliding sleeve then only rotationally engaging with the coupling shaft. Thus, in the neutral position, the electric motor and the first planetary gear set are decoupled from the second planetary gear set, thereby minimizing drag losses. The neutral position is located between the two gear positions.In particular, the actuator moves the sliding sleeve into the respective switching position and thereby switches two gears sequentially, whereby a change between the gears always requires a pass through the neutral position.

[0006] The sliding sleeve is designed to be positively engaged and has positive-locking claws that interact positively with a corresponding claw toothing in the respective gear position to establish a rotationally fixed connection between two shafts. Therefore, the respective claw toothing with which the sliding sleeve interacts positively is to be understood as a shifting element. The shifting unit preferably comprises an unsynchronized claw clutch. Thus, both shifting elements are designed as positive-locking shifting elements. Positive-locking shifting elements can increase the efficiency of the manual transmission due to reduced drag losses. In particular, positive-locking shifting elements are more compact and have an optimized efficiency, offering a cost advantage over friction-locking shifting elements. The use of the sliding sleeve to shift the two gears further increases compactness.

[0007] The shifting elements of the positive-locking shifting unit are designed as gear shifting elements and are thus configured for shifting gears. To shift first gear, only the first shifting element is actuated or closed. To shift second gear, only the second shifting element is actuated or closed. A "shifting element" is a switchable device that, when closed, connects two shafts in a rotationally fixed manner and, when open, decouples the two shafts. The two shafts can then rotate relative to each other.

[0008] The first sun gear serves as the input shaft of the manual transmission and is connected to the electric motor to supply drive power to the manual transmission. The second planetary gear serves as the output shaft of the manual transmission and is connected to the differential. The coupling shaft connects the two planetary gear sets via the shift unit and accommodates the sliding sleeve in all shift positions. Thus, the sliding sleeve is always in rotational engagement with the coupling shaft.

[0009] For the purposes of the invention, a “shaft” is understood to be a rotatable component of the transmission via which associated components of the transmission are connected to one another in a rotationally fixed manner or via which such a connection can be established upon actuation of one of the shift elements. The respective shaft can connect the components axially or radially, or even both axially and radially. For example, the respective shaft can also be in the form of an intermediate piece via which a respective component is connected radially, for example. The term “shaft” does not exclude the possibility that the components to be connected can be designed as a single piece. In particular, two or more shafts connected to one another in a rotationally fixed manner can be designed as a single piece.

[0010] According to a preferred embodiment, the differential is designed as a bevel gear differential. A differential designed as a bevel gear differential has two gear-side output elements, in particular a first output gear and a second output gear. The two output gears each mesh with a compensating element. The compensating elements are mounted in a differential carrier so they can rotate about their own axis. The respective output gear is connected in a rotationally fixed manner to the respective differential output shaft. The differential is driven via the differential carrier, which is configured as the differential input shaft. Furthermore, alternative designs of the differential are also conceivable, for example, as a ball differential, spur gear differential, or planetary differential.The drive power fed into the differential via the differential input shaft is distributed in a conventional manner between the two differential output shafts and transmitted to the drive wheels of the axle. The differential output shafts are designed to be connected to the vehicle's drive wheels in a drivingly effective manner. The respective differential output shaft can be connected to the corresponding vehicle wheel directly or indirectly via a downstream fixed gear, a joint, a propeller shaft, and / or a wheel hub.

[0011] According to one embodiment, the second sun gear shaft is rotationally fixed to the coupling shaft, and the third ring gear shaft is rotationally fixed to a stationary component. This creates a large gear ratio on the second planetary gear set. Alternatively, the third ring gear shaft is rotationally fixed to the coupling shaft, and the second sun gear shaft is rotationally fixed to a stationary component. This reduces the gear ratio on the second planetary gear set. A "stationary component" is understood to mean a component that is fixed in a stationary manner, in particular that is rotationally fixed or integrally connected to a housing or part of a housing.

[0012] According to one embodiment, the differential and the first planetary gear set are arranged partially radially nested. In particular, the differential is arranged axially between the first planetary gear set and the second planetary gear set. The differential is arranged partially within the stepped planetary gear set. Thus, the differential partially axially penetrates the stepped planetary gear set, with the differential partially axially overlapping the stepped planetary gears of the first planetary gear set. This increases the compactness of the drive unit.

[0013] According to one embodiment, at least the second gear of the respective stepped planetary gear is arranged on an outer circumferential surface of the differential. In particular, the differential is arranged axially between the first planetary gear set and the second planetary gear set. Thus, the differential partially penetrates into a space on the stepped planetary gear set created by omitting a sun shaft of the stepped planetary gear set. The differential partially axially overlaps the second gear of the respective stepped planetary gear of the first planetary gear set. This increases the compactness of the drive unit.

[0014] According to one embodiment, the second planetary gear set is arranged axially between the first planetary gear set and the differential. Thus, the differential is spatially separated from the manual transmission and does not overlap the manual transmission, in particular the first and / or second planetary gear set.

[0015] According to one embodiment, at least the shifting unit and the first planetary gear set are arranged in a partially radially nested configuration. Thus, the shifting unit, in particular the sliding sleeve, partially axially overlaps the stepped planetary gears of the first planetary gear set, in particular the second gear of the respective stepped planetary gear. Preferably, the shifting unit and the differential are arranged in a partially radially nested configuration, with the differential being arranged within the shifting unit. This increases the compactness of the drive unit.

[0016] According to one embodiment, the drive unit further comprises a switching element designed as a switchable parking lock, which, when closed, connects the second sun gear shaft and the third ring gear shaft in a rotationally fixed manner. Alternatively, the drive unit further comprises a switching element designed as a switchable parking lock, which, when closed, connects the second sun gear shaft and the second carrier shaft in a rotationally fixed manner. The parking lock has the function of stationary the driven axle when actuated in order to prevent the vehicle from rolling away. This occurs indirectly via the gear ratio of the second planetary gear set. The switching element designed as a switchable parking lock can, for example, be actuated in the radial direction with a pawl or in the axial direction with a claw. The switchable parking lock thus blocks the second planetary gear set by connecting two of the three shafts of the second planetary gear set in a rotationally fixed manner.This completely locks the second planetary gear set, and thus also the output of the manual transmission and the differential input shaft. This has the advantage that the parking lock exerts less torque than with a direct connection to another shaft of the manual transmission. The parking lock can therefore be smaller.

[0017] A vehicle according to the invention comprises a drive unit according to the invention. The above definitions as well as statements regarding technical effects, advantages, and advantageous embodiments of the drive unit according to the invention also apply mutatis mutandis to the vehicle according to the invention.

[0018] Advantageous embodiments of the invention, which are explained below, are illustrated in the drawings, wherein identical or similar elements are provided with the same reference numerals. They show: Fig. 1 is a highly abstracted schematic view of a vehicle with a drive axle having a drive unit according to the invention; Fig. 2 a highly abstracted schematic view of a drive unit according to the invention according to a first embodiment; Fig. 3 a highly abstracted schematic view of a drive unit according to the invention according to a second embodiment; Fig. 4 a highly abstracted schematic view of a drive unit according to the invention according to a third embodiment; Fig. 5 a highly abstracted schematic view of a drive unit according to the invention according to a fourth embodiment; Fig. 6 a highly abstracted schematic view of a drive unit according to the invention according to a fifth embodiment and Fig. 7 a highly abstracted schematic view of a drive unit according to the invention according to a sixth embodiment.

[0019] Fig. 1 shows a vehicle 100 with a first axle 101 with two vehicle wheels R1, R2 and a second axle 102 with two vehicle wheels R3, R4. In the present case, the first axle 101 is designed as the rear drive axle of the vehicle 100 and is equipped with a drive unit according to the invention. The drive unit comprises an electric machine EM1, which is configured to generate drive power, a manual transmission SG with two gears and a differential DG. Thus, the vehicle 100 is designed as an electric vehicle, i.e. as an electrically driven vehicle. The drive unit is arranged transversely to the vehicle's longitudinal direction and is drivingly connected to the vehicle wheels R1, R2 of the first axle 101. In the present case, no further drive unit is arranged on the second axle 102, i.e. on the front axle of the vehicle 100, thereby saving costs, weight and installation space.Alternatively, the drive unit can be arranged on the front axle of the vehicle 100 instead of on the rear axle. To implement an all-wheel drive system, a further drive unit can be arranged on the second axle 102 and can be drivingly connected to the vehicle wheels R3, R4 of this axle 102.

[0020] Fig. 2 shows a drive unit according to Fig. 1. A first sun shaft SO1, provided as a drive shaft, is intended to connect the electric machine EM to the manual transmission SG, wherein a second carrier shaft ST2, provided as an output shaft, is intended to connect the manual transmission SG to the differential DG. The drive power of the electric machine EM is introduced into the manual transmission SG via the first sun shaft SO1, and the drive power is introduced into the differential DG via the second carrier shaft ST2. The electric machine EM has a housing-fixed stator EMS and a rotatable rotor EMR, wherein the first sun shaft SO1 is connected to the rotor EMR in a rotationally fixed manner. The electric machine EM, the manual transmission SG, and the differential DG are arranged on a common rotational axis R and are thus coaxial with one another. The embodiments described in Fig. 2 to Fig. 7 show only the “upper” half of the respective drive unit, whereby the “lower”, not shown half is designed symmetrically to the “upper” half.

[0021] The manual transmission SG has a positive-locking shifting unit with a first shifting element A, a second shifting element B, and a single axially displaceable sliding sleeve SM. The manual transmission SG also comprises a first planetary gear set PS1, a second planetary gear set PS2, and a coupling shaft W for connecting the second planetary gear set PS2 to the first planetary gear set PS1 and for receiving the sliding sleeve SM in all shift positions of the shifting unit. The first planetary gear set PS1 is designed as a stepped planetary gear set and has exactly four shafts, namely the first sun gear shaft SO1, a first ring gear shaft HR1, a second ring gear shaft HR2, and a first planetary gear shaft ST1. The first planetary gear shaft ST1 carries a plurality of stepped planetary gears, each having a first gear Z1 and a second gear Z2, which are connected to one another in a rotationally fixed manner.The first gear Z1 is in meshing engagement with the first sun gear shaft SO1 and the first ring gear shaft HR1, whereby the first ring gear shaft HR1 is connected in a rotationally fixed manner to a stationary component designed as a housing G. The second gear Z2 is in meshing engagement with the second ring gear shaft HR2. The second planetary gear set PS2 is designed as a negative planetary gear set and comprises three shafts, namely a second sun gear shaft SO2, a third ring gear shaft HR3 and the second carrier shaft ST2. The second carrier shaft ST2 carries several planet gears that mesh with the second sun gear shaft SO2 and the third ring gear shaft HR3, i.e. are in meshing engagement. The third ring gear shaft HR3 is connected in a rotationally fixed manner to a stationary component designed as a housing G. The second sun gear shaft SO2 is connected in a rotationally fixed manner to the coupling shaft W.

[0022] The differential DG and the first planetary gear set PS1 are partially radially nested. The second gear Z2 of the respective stepped planetary gear is arranged on a circumference of the differential DG. The differential DG therefore axially overlaps the second gear Z2 of the respective stepped planetary gear of the first planetary gear set PS1, which saves installation space and increases compactness. The second planetary gear set PS2, intended as the output planetary gear set, is arranged on the other side of the differential DG and has no axial overlap with the differential DG. The shifting unit with the two shift elements A, B and the associated sliding sleeve SM are radially nested on a large diameter on the circumference of the differential DG and partly also on the circumference of the stepped planetary gear set. The shifting unit, the first planetary gear set PS1 and the differential DG are therefore at least partially radially nested.This saves installation space and increases compactness.

[0023] The positive-locking shift unit has exactly two shift elements A, B and three shift positions, with the three shift positions being achieved by axially displacing the sliding sleeve SM. The sliding sleeve SM has claw shift elements and can be axially displaced into the respective shift position by means of a single actuator AK. Thus, all three shift positions of the shift unit are arranged linearly and consist of two gear positions and a neutral position, with the neutral position located between the two gear positions. Gears one and two are shifted one after the other or sequentially by displacing the sliding sleeve SM in an axial direction, beyond the neutral position. This not only saves weight and components, but also costs, installation space and assembly effort.The first switching element A allows the second ring gear shaft HR2 to be connected in a rotationally fixed manner to the coupling shaft W and the second sun gear shaft SO2, which is connected in a rotationally fixed manner to the coupling shaft W. The second switching element B allows the second carrier shaft ST2 to be connected in a rotationally fixed manner to the coupling shaft W and the second sun gear shaft SO2, which is connected in a rotationally fixed manner to the coupling shaft W.

[0024] First gear is engaged when the sliding sleeve SM is in a first gear position, i.e., a first shift position. The first shift element A, in an actuated or closed state—i.e., in the first shift position of the sliding sleeve SM—connects the second ring gear shaft HR2 and the coupling shaft W to engage first gear. First gear is thus engaged by actuating the sliding sleeve SM and engaging only the first shift element A. In first gear, the first planetary gear set PS1 acts as a Wolfrom transmission.

[0025] First gear is disengaged by axially shifting the sliding sleeve SM into a neutral position, i.e., a second shift position, in this case to the right. In the second shift position of the sliding sleeve SM, the sliding sleeve SM is only in rotational engagement with the coupling shaft W. In this neutral position, both shift elements A and B are open, so that the electric machine EM as well as the first planetary gear set PS1 are decoupled from the coupling shaft W and the second planetary gear set PS2 and do not cause any losses, for example, through rotating bearings. In this neutral position, the electric machine EM can synchronize the target gear. In this case, Fig. 2 shows this second switching position of the sliding sleeve SM.

[0026] Second gear is engaged by axially shifting the sliding sleeve SM into a second gear position, i.e., a third shift position, in this case further to the right. The second shifting element B, in an actuated or closed state—i.e., in the third shift position of the sliding sleeve SM—connects the first carrier shaft ST1 and the coupling shaft W to engage second gear. Second gear is thus engaged by actuating the sliding sleeve SM and closing only the second shifting element B. In second gear, the first planetary gear set PS1 functions as a simple planetary gear set.

[0027] The differential DG is designed as a ball or bevel gear differential and has a differential input shaft D1 and two differential output shafts D2, D3. The differential input shaft D1 is connected in a rotationally fixed manner to the second carrier shaft ST2. The differential DG, designed as a ball or bevel gear differential, has two wheel-side output elements, in particular a first output gear and a second output gear. The two output gears each mesh with a compensating element. The compensating elements are mounted in a differential carrier designed as a differential input shaft D1, rotatably mounted about their own axis. The respective output gear is connected in a rotationally fixed manner to the respective differential output shaft D2, D3. The differential DG is driven via the differential carrier, which in this case is connected in a rotationally fixed manner to the third carrier shaft ST3.Arrows on the differential output shafts D2, D3 indicate a connection to a respective vehicle wheel of this vehicle axle.

[0028] Fig. Figure 3 shows a second embodiment of the drive unit according to the invention. The drive unit according to Fig. 3 essentially corresponds to the drive unit according to Fig. 2, whereby the difference between these two embodiments lies in the arrangement of a switching element P. The switching element P is designed as a switchable parking lock and, in a closed state, connects the second sun gear shaft SO2 as well as the coupling shaft W connected thereto in a rotationally fixed manner and the third ring gear shaft HR3, which is fixed to the housing G. This blocks the second planetary gear set PS2, so that not only the second planetary gear set PS2, but also the output of the manual transmission SG and thus the differential input shaft D1 are fixed. It is advantageous that a lower torque is applied to the switching element P than with a direct connection of the switching element P at another point of the manual transmission SG. This allows the switching element P to be dimensioned smaller, thereby saving costs and installation space. Otherwise, the embodiment according to Fig. 3 the embodiment according to Fig. 2, to which reference is made.

[0029] Fig. 4 shows a third embodiment of the drive unit according to the invention. The drive unit according to Fig. 4 essentially corresponds to the drive unit according to Fig. 3, whereby the difference between these two embodiments lies in the connection of the switching element P. In the present case, the switching element P, in a closed state, connects the second sun shaft SO2 and the coupling shaft W connected thereto in a rotationally fixed manner with the second carrier shaft ST2 and the differential input shaft D1 connected thereto in a rotationally fixed manner. This blocks the second planetary gear set PS2, so that not only the second planetary gear set PS2, but also the output, in particular the differential input shaft D1, is fixed. Otherwise, the embodiment according to Fig. 4 the embodiment according to Fig. 3, to which reference is made.

[0030] Fig. Figure 5 shows a fourth embodiment of the drive unit according to the invention. The drive unit according to Fig. 5 essentially corresponds to the drive unit according to Fig. 2, whereby the difference between these two embodiments lies in the connection of the second planetary gear set PS2. In this case, the third ring gear shaft HR3 is connected in a rotationally fixed manner to the coupling shaft W, whereby the second sun gear shaft SO2 is connected in a rotationally fixed manner to the stationary component formed as a housing G. The second planetary gear set PS2 thus provides a lower transmission ratio than the second planetary gear set PS2 according to Fig. 2. This connection is suitable, for example, when lower pulling forces are required when starting off, but higher driving speeds are required. Here, too, a parking lock can be used according to Fig. 3 or Fig. 4. Otherwise, the embodiment corresponds to Fig. 5 the embodiment according to Fig. 2, to which reference is made.

[0031] Fig. Figure 6 shows a fifth embodiment of the drive unit according to the invention. The drive unit according to Fig. 6 essentially corresponds to the drive unit according to Fig. 2, whereby the difference between these two embodiments lies in the arrangement of the differential DG. In the present case, the differential DG is not arranged radially nested with the stepped planetary gear set and the shifting unit, but is arranged on an opposite side of the second planetary gear set PS2 adjacent to the second planetary gear set PS2. Thus, the second planetary gear set PS2 is arranged axially between the first planetary gear set PS1 and the differential DG. The shifting unit is partially radially stacked with the first planetary gear set. The advantage of this is that the second sun gear shaft SO2 can have a smaller diameter, since the output shaft of the manual transmission SG, i.e. the second carrier shaft ST2, which is connected in a rotationally fixed manner to the differential input shaft D1, does not have to pass through the second planetary gear set PS2. This results in a larger stationary gear ratio of the second planetary gear set PS2. Otherwise, the embodiment according to Fig. 6 the embodiment according to Fig. 2, to which reference is made.

[0032] Fig. Figure 7 shows a sixth embodiment of the drive unit according to the invention. The drive unit according to Fig. 7 essentially corresponds to the drive unit according to Fig. 6, the difference between these two embodiments being the arrangement of a shifting element P. The shifting element P is designed as a switchable parking lock and, in a closed state, connects the second sun gear shaft SO2 and the coupling shaft W connected thereto in a rotationally fixed manner, and the third ring gear shaft HR3, which is fixed to the housing G. This blocks the second planetary gear set PS2, so that not only the second planetary gear set PS2, but also the output, in particular the differential input shaft D1, are fixed. It is advantageous that a lower torque is applied to the shifting element P than with a direct connection of the shifting element P at another location of the manual transmission SG. This allows the shifting element P to be dimensioned smaller, thereby saving costs and installation space. The shifting element P is arranged axially between the first and second planetary gear sets PS1, PS2. Otherwise, the embodiment according to Fig. 7 the embodiment according to Fig. 6, to which reference is made. Reference symbol 100 vehicles 101 first axis 102 second axis R1 vehicle wheel R2 vehicle wheel R3 vehicle wheel R4 vehicle wheel On drive shaft From output shaft SG manual transmission EM electric machine EMS stator of the electrical machine EMR rotor of the electric machine PS1 first planetary gear set SO1 first solar wave HO1 first ring gear shaft HO2 second ring gear shaft ST1 first bridge wave Z1 first gear Z2 second gear PS2 second planetary gear set SO2 second solar wave HO3 third ring gear shaft ST2 second web wave AK Actuator G Housing R axis of symmetry DG Differential D1 differential input shaft D2 first differential output shaft D3 second differential output shaft SM sliding sleeve A first switching element B second switching element P switching element QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] DE 11 2011 104 355 T5

[0002]

Claims

[1] Drive unit for a vehicle (100), comprising • an electrical machine (EM) with a rotor (EMR) and a stator (EMS), • a coaxially arranged differential (DG) with a differential input shaft (D1) and two differential output shafts (D2, D3), • a coaxially arranged manual transmission (SG) with a first planetary gear set (PS1), a second planetary gear set (PS2) and a positive-locking switching unit arranged therebetween with a first switching element (A), a second switching element (B) and a single sliding sleeve (SM) which can be moved axially between exactly three switching positions, and • a coupling shaft (W) for connecting the second planetary gear set (PS2) to the first planetary gear set (PS1) and for receiving the sliding sleeve (SM) in all switching positions, • wherein the first planetary gear set (PS1) is designed as a stepped planetary gear set and has exactly four shafts, namely a first sun shaft (SO1), a first ring gear shaft (HR1), a second ring gear shaft (HR2) and a first carrier shaft (ST1) with a plurality of stepped planetary gears, each having a first and second non-rotatably connected gear (Z1, Z2), wherein the first gear (Z1) is in meshing engagement with the first sun shaft (SO1) and the first ring gear shaft (HR1), wherein the second gear (Z2) is in meshing engagement with the second ring gear shaft (HR2), wherein the first sun shaft (SO1) is non-rotatably connected to the rotor (EMR), wherein the first ring gear shaft (HR1) is non-rotatably connected to a stationary component, • wherein the second planetary gear set (PS2) comprises a second sun shaft (SO2), a third ring gear shaft (HR3), a second carrier shaft (ST2) and a plurality of planetary gears, wherein the second carrier shaft (ST2) is connected in a rotationally fixed manner to the differential input shaft (D1), • wherein in the closed state of the first switching element (A) a first gear is engaged with a first gear ratio, wherein in the first gear the second ring gear shaft (HR2) and the second sun shaft (SO2) are connected in a rotationally fixed manner, • wherein in the closed state of the second switching element (B) a second gear with a second transmission ratio is engaged, wherein in the second gear the first carrier shaft (ST1) and the coupling shaft (W) are connected in a rotationally fixed manner. [2] Drive unit according to claim 1, wherein the second sun shaft (SO2) is connected in a rotationally fixed manner to the coupling shaft (W), wherein the third ring gear shaft (HR3) is connected in a rotationally fixed manner to a stationary component. [3] Drive unit according to claim 1, wherein the third ring gear shaft (HR3) is connected in a rotationally fixed manner to the coupling shaft (W), wherein the second sun shaft (SO2) is connected in a rotationally fixed manner to a stationary component. [4] Drive unit according to one of the preceding claims, wherein the differential (DG) and the first planetary gear set (PS1) are arranged partially radially nested. [5] Drive unit according to claim 4, wherein at least the second gear (Z2) of the respective stepped planetary gear is arranged on a circumference of the differential (DG). [6] Drive unit according to one of claims 1 to 3, wherein the second planetary gear set (PS2) is arranged axially between the first planetary gear set (PS1) and the differential (DG). [7] Drive unit according to one of the preceding claims, wherein at least the switching unit and the first planetary gear set (PS1) are arranged partially radially nested. [8] Drive unit according to one of the preceding claims, further comprising a switching element (P) designed as a switchable parking lock, which in a closed state connects the second sun shaft (SO2) and the third ring gear shaft (HR3) in a rotationally fixed manner. [9] Drive unit according to one of claims 1 to 8, further comprising a switching element (P) designed as a switchable parking lock, which in a closed state connects the second sun shaft (SO2) and the second web shaft (ST2) in a rotationally fixed manner. [10] Vehicle (100) comprising a drive unit according to one of the preceding claims.

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