Drive unit with a manual transmission for a vehicle

Abstract

Drive unit for a vehicle (100), comprising an electric machine (EM) and a coaxially arranged transmission (SG) connected to the electric machine (EM) via a drive shaft (An), the transmission (SG) comprising: • a first shifting unit (SE1) with a first shifting element (A) and a second shifting element (B), • a second shifting unit (SE2) with a third shifting element (C) and a fourth shifting element (D), • a planetary gear set (PS) with several planet gears, a first sun shaft (SO1), a first ring gear shaft (HR1) and a first carrier shaft (ST1), • a stepped planetary gear set (SP) with several stepped planet gears, a second sun shaft (SO2), a second ring gear shaft (HR2), a third ring gear shaft (HR3) and a second carrier shaft (ST2), and • a differential (DG) with a differential input shaft (D1) and two differential output shafts (D2, D3),• wherein a first gear (Z1) of the respective stepped planetary gear is in mesh with the second sun shaft (SO2) and the second ring gear shaft (HR2), • wherein a second gear (Z2) of the respective stepped planetary gear is in mesh with the third ring gear shaft (HR3), • wherein the second web shaft (ST2) is non-rotatably connected to the differential input shaft (D1), • wherein the planetary gear set (PS) is designed to be switchable and one of its three shafts is non-rotatably connected to the drive shaft (An), another of its three shafts is non-rotatably connected to the second sun shaft (SO2), and another of its three shafts is switchable via the first switching unit (SE1), • wherein in the closed state of the first switching element (A) the planetary gear set (PS) is locked, • wherein in the closed state of the second switching element (B) one of the three shafts of the planetary gear set (PS) is non-rotatably connected to a stationary component,• wherein in the closed state of the third switching element (C) the second ring gear shaft (HR2) is non-rotatably connected to the stationary component, • wherein in the closed state of the fourth switching element (D) the third ring gear shaft (HR3) is non-rotatably connected to the stationary component.

Description

The invention relates to a drive unit for a vehicle, wherein the drive unit has an electric machine and a transmission with two gears. The invention further relates to a method for setting four gears with different transmission ratios for the transmission of such a drive unit. The invention also relates to a vehicle having such a drive unit.For example, DE 10 2019 205 747 A1 discloses a transmission comprising an input shaft, a first output shaft, a second output shaft, a first planetary gear set and a second planetary gear set connected to the first planetary gear set. The planetary gear sets each include a plurality of elements, wherein the first output shaft is rotationally fixedly connected to a second element of the first planetary gear set, the second output shaft is rotationally fixedly connected to a third element of the second planetary gear set, a third element of the first planetary gear set is rotationally fixedly connected to a first element of the second planetary gear set via a shaft, and a second element of the second planetary gear set is fixed to a rotationally fixed component. The transmission further comprises a third planetary gear set comprising three elements and two shift elements. A first shift element is designed to block the third planetary gear set by connecting two of its elements in a rotationally fixed manner. A second shift element is configured to fix a first element of the third planetary gear set to the torque-proof component. A second element of the third planetary gear set is connected via an intermediate shaft to the first element of the first planetary gear set in a rotationally fixed manner. A third element of the third planetary gear set is connected to the input shaft in a rotationally fixed manner.From document US 2022 / 0 373 067 A1 a drive train device is known which comprises an engine connected to an input shaft. A first planetary gear is arranged to be coaxial with the motor. The driving device further includes a first rotation element, a second rotation element, and a third rotation element, and a second planetary gear set that is arranged to be coaxial with the first planetary gear set and that includes a fourth rotation element. The drive unit further comprises a fifth rotational element, a sixth rotational element and a step pinion as well as a differential gear which is arranged coaxially with the second planetary gear.The object of the present invention is to provide an alternative drive unit with a gearbox for a vehicle. In particular, the drive unit should be of compact design and have a high transmission ratio. Furthermore, the drive unit should have a plurality of gear stages. The object is achieved by a drive unit having the features of independent claim 1. advantageous embodiments are the subject matter of the dependent claims, the following description and the figures.A drive unit according to the invention for a vehicle comprises an electric machine and a transmission arranged coaxially thereto, which transmission is connected to the electric machine via a drive shaft, the transmission having a first shift unit with a first shift element and a second shift element, a second shift unit with a third shift element and a fourth shift element, a planetary set with a plurality of planetary gears, a first sun shaft, a first ring gear shaft and a first carrier shaft, a stepped planetary set with a plurality of stepped planetary gears, a second sun shaft, a second ring gear shaft, a third ring gear shaft and a second carrier shaft, and a differential with a differential input shaft and two differential output shafts, wherein a first gear of the respective stepped planetary gear meshes with the second sun shaft and the second ring gear shaft, wherein a second gearwheel of the respective stepped planetary gearwheel is in toothed engagement with the third ring gear shaft, wherein the second carrier shaft is connected to the differential input shaft in a rotationally fixed manner, wherein the planetary set is designed to be switchable and one of its three shafts is connected to the drive shaft in a rotationally fixed manner, wherein another of its three shafts is connected to the second sun shaft in a rotationally fixed manner, wherein another of its three shafts is switchable via the first switching unit, wherein the planetary set is blocked in the closed state of the first switching element, wherein one of the three shafts of the planetary set is connected to a stationary component in a rotationally fixed manner in the closed state of the third switching element, wherein the second ring gear shaft is connected to the stationary component in a rotationally fixed manner in the closed state of the third switching element, wherein the third ring gear shaft is connected to the stationary component in a rotationally fixed manner in the closed state of the fourth switching element. To block the planetary set, two of the three shafts of the planetary set are connected to one another in a rotationally fixed manner via the first shift element. As a result, a block revolution and thus a transmission ratio of 1 is set at the planetary set.The planetary set is switchable via the first shift unit and is designed as a minus planetary set with three shafts, namely a sun shaft, a ring gear shaft and a carrier shaft, wherein the carrier shaft rotatably supports a plurality of planetary gears.The stepped planetary gear set can be shifted via the second shift unit, has a sun shaft, two ring gear shafts and a carrier shaft, wherein the carrier shaft rotatably supports a plurality of stepped planetary gears. The first gearwheel, i.e. the first toothed section, of the respective stepped planetary gear is connected in a rotationally fixed manner to the second gearwheel, i.e. to the second toothed section, of the respective stepped planetary gear. The stepped planet gears are formed in one piece, for example. The sun shaft is formed as the drive shaft of the stepped planetary gear set and the carrier shaft is formed as the output shaft of the stepped planetary gear set.A "shaft" is understood in the sense of the invention to mean a rotatable component of the transmission, via which respective associated components of the transmission are connected to one another in a rotationally fixed manner or via which such a connection can be produced when one of the shift elements is actuated. The respective shaft can connect the components to one another axially or radially or also both axially and radially. Thus, the respective shaft can also be present as an intermediate piece, via which a respective component is connected, for example, radially. The term "shaft" does not exclude that the components to be connected can be embodied in one piece. In particular, two or more shafts connected to one another in a rotationally fixed manner can be formed in one piece.The transmission is always driven via the drive shaft, the output always being driven via the differential output shafts. The respective differential output shaft is connected at least indirectly to a vehicle wheel in a drive-effective manner. For example, a single power unit is used in an electric drive axle for an electric vehicle. The transmission has exactly four gears, which are shifted by means of the two shift units, in particular by means of the four shift elements, whereby a high energy efficiency for electric vehicles is created.For example, the vehicle is designed as a construction machine and has two driving gears which can be shifted in the transmission range in order to achieve higher torques, in particular if the vehicle weight is subject to great fluctuations on account of the load or when driving empty. The planetary set provided as a pretransmission can be switched by means of the first switching unit in order to achieve a displacement of the driving gears of the vehicle.The shift elements are designed as gear shift elements and are thus configured for shifting gears. A "shifting element" is understood to mean a shiftable device which, in a closed state, connects two shafts or one shaft and a stationary component to one another in a rotationally fixed manner and, in an open state, decouples the two shafts or the shaft and the stationary component from one another. Two shafts can then rotate relative to each other.According to a method according to the invention, four gears can be set with the two shift units, in particular with the four shift elements.In a first gear, the second shift element and the fourth shift element are closed and the first shift element and the third shift element are open. As a result, one of the three shafts of the planetary set is connected to a stationary component in a rotationally fixed manner via the first switching unit and the third ring gear shaft is connected to the stationary component in a rotationally fixed manner via the second switching unit.A "stationary component" is understood to mean a component that is fixed stationary, in particular is connected in a rotationally fixed manner or in one piece to a housing or a part of a housing.In a second gear, the first shift element and the fourth shift element are closed and the second shift element and the third shift element are open. As a result, the planetary set is blocked via the first shift unit and the third ring gear shaft is connected to the stationary component in a rotationally fixed manner via the second shift unit.In a third gear, the second shift element and the third shift element are closed and the first shift element and the fourth shift element are open. As a result, one of the three shafts of the planetary set is connected to the stationary component in a rotationally fixed manner via the first switching unit and the second ring gear shaft is connected to the stationary component in a rotationally fixed manner via the second switching unit.In a fourth gear, the first shift element and the third shift element are closed and the second shift element and the fourth shift element are open. As a result, the planetary set is blocked via the first shift unit and the second ring gear shaft is connected to the stationary component in a rotationally fixed manner via the second shift unit.According to a preferred embodiment, all four shift elements are designed as form-locking shift elements. For example, a form-fitting shifting element is designed as a claw clutch. By means of positively locking shift elements, the efficiency of the transmission can be increased on account of reduced drag losses. In particular, form-locking shift elements are more compact and efficiency-optimized and have a cost advantage compared to frictionally engaging shift elements. Alternatively, at least one shifting element can be designed as a frictional shifting element, for example as a multiplate clutch. With frictionally engaging shift elements, a conventional load shift during a gear change is possible.According to a preferred embodiment, the respective shift unit has in each case a single axially displaceable sliding sleeve with in each case three shift positions. In particular, the respective shift unit has a neutral position between two gear positions. In a respective neutral position, two shafts or one shaft and one stationary component are decoupled from one another via the respective shift unit, wherein the first sliding sleeve is then only in rotational engagement with a shaft of the planetary set and the second sliding sleeve is only in rotational engagement with the stationary component. The first switching element and the second switching element therefore form the first switching unit having three switching positions, wherein the third switching element and the fourth switching element form the second switching unit having three switching positions.The respective sliding sleeve is displaceable into the respective switching position by means of a respective single actuator. In particular, the respective actuator displaces the respective sliding sleeve into the respective switching position. The respective sliding sleeve preferably has form-fitting claws which, in the respective gear position, interact in a form-fitting manner with a respective corresponding claw toothing in order to set a rotationally fixed connection between two shafts or a shaft and a stationary component. The respective claw toothing with which the respective sliding sleeve cooperates in a positive-locking manner is therefore to be understood as a switching element. In particular, the respective sliding sleeve is arranged axially between the two gear positions in the neutral position, so that a change between the gears always requires a passage through the neutral position. Preferably, the shift unit comprises an unsynchronized claw clutch.According to one embodiment, the first sun shaft is connected to the drive shaft in a rotationally fixed manner, wherein the first carrier shaft is connected to the second sun shaft in a rotationally fixed manner, wherein the first ring gear shaft is connected to the first sun shaft in a rotationally fixed manner in the closed state of the first shift element in order to block the planetary set, wherein the first ring gear shaft is connected to the stationary component in a rotationally fixed manner in the closed state of the second shift element. Reference is made here to the exemplary embodiment according to FIG. 2.According to an alternative embodiment, the first ring gear shaft is connected to the drive shaft in a rotationally fixed manner, wherein the first carrier shaft is connected to the second sun shaft in a rotationally fixed manner, wherein the first sun shaft is connected to the first carrier shaft in a rotationally fixed manner in the closed state of the first shift element in order to block the planetary set, wherein the first sun shaft is connected to the stationary component in a rotationally fixed manner in the closed state of the second shift element. Reference is made here to the exemplary embodiment according to FIG. 3.According to one embodiment, the differential is designed as a bevel gear differential. The bevel gear differential is preferably arranged at least partially radially stacked with the stepped planetary gear set. As a result, the transmission is made axially more compact. In other words, the bevel gear differential is arranged at least partially or completely radially inside the stepped planetary gear set. For this purpose, the bevel gear differential protrudes at least partially or completely axially into the stepped planetary gear set and is designed to overlap at least partially or completely axially with the stepped planetary gear set. For example, the planetary set is arranged axially adjacent to the stepped planetary set, in particular axially between the electric machine and the stepped planetary set. In other words, the stepped planetary gear set and the planetary gear set do not have an axial overlap. This increases the compactness of the gearbox in the radial direction.A differential embodied as a bevel gear differential has two wheel-side output elements, in particular a first output wheel and a second output wheel. The two output wheels mesh with two compensating elements. The compensating elements are rotatably mounted in a differential cage about their own axis. The respective output wheel is connected to the respective differential output shaft in a rotationally fixed manner. The differential is driven via the differential cage, which is configured as a differential input shaft. The drive power fed into the differential gear is distributed to the differential output shafts and transmitted to the drive wheels of the axle. The differential output shafts are configured to be drivingly connected to the drive wheels of the vehicle. The respective differential output shaft can be connected directly or directly or indirectly or indirectly via a joint, a propeller shaft and / or a wheel hub to the associated vehicle wheel.According to one embodiment, the drive shaft is designed as a hollow shaft and one of the two differential output shafts is passed axially at least through the electric machine, the drive shaft and the planetary set. For example, the first differential output shaft extends axially through the electric machine, the input shaft, and the planetary set. In particular, the first differential output shaft also extends at least partially axially through the stepped planetary gear set.A vehicle according to the invention comprises at least one drive unit according to the invention. The above definitions and statements regarding technical effects, advantages and advantageous embodiments of the drive unit according to the invention also apply analogously to the vehicle according to the invention. The vehicle is preferably designed as a construction machine.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. The following are shown: FIG. 1 is a greatly abstract schematic view of a vehicle having a drive axle which has a drive unit according to the invention; FIG. 2 shows a greatly abstract schematic view of the drive unit according to the invention according to a first embodiment; FIG. 3 shows a greatly abstract schematic view of the drive unit according to the invention according to a second embodiment; and FIG. 4 shows a switching matrix for the drive units according to the invention.FIG. 1 shows a vehicle 100 having a first axle 101 with two vehicle wheels R 1, R 2 and a second axle 102 with two vehicle wheels R 3, R 4. In the present case, the first axle 101 is designed as a 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 EM, which is configured to generate a drive power, and a transmission SG with two gears. The vehicle 100 is therefore designed as an electric vehicle, i.e. as an electrically drivable vehicle. The drive unit is arranged transversely to the vehicle longitudinal direction and is operatively connected to the vehicle wheels R 1, R 2 of the first axle 101 in a drive-effective manner. In the present case, no further drive unit is arranged on the second axle 102, that is to say on the front axle of the vehicle 100, as a result of which costs, weight and installation space are saved. Alternatively, the drive unit may be disposed 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 be connected in a drive-effective manner to the vehicle wheels R 3, R 4 of this axle 102.FIG. 2 shows the drive unit with the shift transmission SG according to a first embodiment. The transmission SG is connected via a drive shaft An to an electric machine EM, which has a stator EMS fixed to the housing and a rotor EMR that can rotate. The electric machine EM is arranged coaxially with the transmission SG. The transmission SG has a first shifting element A, a second shifting element B, a third shifting element C and a fourth shifting element D for shifting four gears, which are listed in the shifting matrix according to FIG. 4. The transmission SG and the electric machine EM thus form an electric drive unit with four gears.The transmission SG also has a planetary set PS, a stepped planetary set SP and a differential DG with a differential input shaft D 1 and two differential output shafts D 2, D 3. The planetary set PS is designed as a shiftable minus planetary set and comprises three shafts, namely a first sun shaft SO1, a first ring gear shaft HR1 and a first carrier shaft ST1. The first carrier shaft ST 1 carries a plurality of planetary gears, which are in toothed engagement with the first sun shaft SO 1 and the first ring gear shaft HR 1, respectively. The stepped planetary gear set SP includes four shafts, namely a second sun shaft SO2, a second ring gear shaft HR2, a third ring gear shaft HR3 and a second carrier shaft ST2. The second carrier shaft ST 2 carries a plurality of stepped planetary gears, each of which has a first gearwheel Z 1 and a second gearwheel Z 2 connected thereto in a rotationally fixed manner. The first gearwheel Z 1 of the respective stepped planetary gear meshes with the second sun shaft SO 2 and the second ring gear shaft HR 2. The second gearwheel Z 2 of the respective stepped planetary gearwheel is in toothed engagement with the third ring gearwheel shaft HR 3.The first sun shaft SO 1 is connected to the drive shaft An in a rotationally fixed manner. The first carrier shaft ST 1 is connected to the second sun shaft SO 2 in a rotationally fixed manner. The second carrier shaft ST 2 is connected to the differential input shaft D 1 in a rotationally fixed manner. Via the first shifting element A, the first ring gear shaft HR 1 can be connected to the first sun shaft SO 1 in a rotationally fixed manner in order to block the planetary set PS and to set a transmission ratio of 1 at the planetary set PS. Via the second shifting element B, the first ring gear shaft HR 1 can be connected in a rotationally fixed manner to a stationary component designed as a housing G, in order to set a different transmission ratio at the planetary set PS. Via the third shifting element C, the second ring gear shaft HR 2 can be connected in a rotationally fixed manner to the stationary component designed as a housing G, in order to set a transmission ratio at the stepped planetary gear set SP. Via the fourth shifting element D, the third ring gear shaft HR 3 can be connected in a rotationally fixed manner to the stationary component designed as a housing G, in order to set a different transmission ratio at the stepped planetary gear set SP.The transmission SG has a rotational axis of symmetry R which coincides with the drive shaft An and the two differential output shafts D 2, D 3. The electric machine EM and the transmission SG with the differential DG are arranged coaxially. The differential DG is designed as a bevel gear differential and is arranged at least partially radially stacked with the stepped planetary gear set SP. The planetary gear set PS is arranged axially between the electric machine EM and the stepped planetary gear set SP. As a result, the drive unit is designed to be particularly compact. The bevel gear differential has two driven elements on the wheel side, in particular a first driven wheel 21 and a second driven wheel 22, the two driven wheels 21, 22 respectively mesh with two compensating elements 23, 24. The respective output wheel 21, 22 is connected to the respective differential output shaft D 2, D 3 in a rotationally fixed manner. The differential DG is driven via the differential cage 20, which is configured as a differential input shaft D 1. The drive power fed into the differential DG is distributed to the differential output shafts D 2, D 3 and transmitted to the drive wheels of the axle, which in the present case are visualized in a simplified manner by arrows on the differential output shafts D 2, D 3. The differential output shafts D 2, D 3 are configured to be drive-operatively connected to the drive wheels of the vehicle. The respective differential output shaft D 2, D 3 can be connected directly or directly or indirectly or indirectly via a joint, a propeller shaft and / or a wheel hub to the associated vehicle wheel.The first shifting element A and the second shifting element B are formed jointly to form a first shifting unit SE 1 having three shift positions, wherein the first shifting unit SE 1 has a single axially displaceable first sliding sleeve SM 1, with which the three shift positions are realized. The first sliding sleeve SM 1 has claw shift elements and is axially displaceable into the respective shift position by means of a first actuator AK 1. Consequently, all three shift positions of the first shift unit SE 1 are arranged linearly and are composed of two gear positions and a neutral position, wherein the neutral position is arranged between the two gear positions.The third shifting element C and the fourth shifting element D are formed jointly to form a second shifting unit SE 2 having three shift positions, wherein the second shifting unit SE 2 has a single axially displaceable second sliding sleeve SM 2, with which the three shift positions are realized. The second sliding sleeve SM 2 has claw shift elements and is axially displaceable into the respective shift position by means of a second actuator AK 2. Consequently, all three shift positions of the second shift unit SE 2 are arranged linearly and are composed of two gear positions and a neutral position, wherein the neutral position is arranged between the two gear positions.The gears one to four are shifted into a respective gear position by shifting the sliding sleeves SM 1, SM 2. This not only saves weight and components, but also costs, installation space and assembly effort. In the present case, the first shift unit SE 1 is arranged radially stacked on the circumference of the planetary gear set PS and the second shift unit SE 2 is arranged radially stacked on the circumference of the stepped planetary gear set SP, whereby axial installation space can be saved.FIG. 3 shows a second embodiment of the drive unit according to the invention. The drive unit according to FIG. 3 corresponds substantially to the drive unit according to FIG. 2, wherein the difference between these two embodiments consists in the connection of the planetary gear set PS and, as a result, smaller pretransmissions are generated. In the present case, the first ring gear shaft HR 1 is connected to the drive shaft An in a rotationally fixed manner, wherein the first carrier shaft ST 1 is connected to the second sun shaft SO 2 in a rotationally fixed manner, wherein the first sun shaft SO 1 is connected to the first carrier shaft ST 1 in a rotationally fixed manner in the closed state of the first shift element A in order to block the planetary set PS, wherein the first sun shaft SO 1 is connected in a rotationally fixed manner to the stationary component designed as a housing G in the closed state of the second shift element B. Otherwise, the exemplary embodiment according to FIG. 3 corresponds to the exemplary embodiment according to FIG. 2, to which reference is made.The drive trains according to FIGS. 2 and 3 each have four gears G 1, G 2, G 3, G 4, which are illustrated in the shift matrix according to FIG. 4, wherein the respective shift elements A, B, C, D are listed in the columns of the shift matrix, and wherein the respective gears G 1, G 2, G 3, G 4 are listed in the rows of the shift matrix. By entering a cross in a respective box of the switching matrix, a closed state of the respective switching element A, B, C, D is represented, wherein an empty box indicates an open state of the respective switching element A, B, C, D. The gear changes G 1, G 2, G 3, G 4 can be performed in any order. For example, the vehicle can be designed as a construction machine and have two gears that can be shifted in the transmission range in order to achieve higher torques. The planetary set PS provided as a pretransmission can be switched over by means of the first switching unit SE 1 in order to achieve a displacement of the driving gears of the vehicle.According to FIG. 4, in a first gear G 1, the second shift element B and the fourth shift element D are closed and the first shift element A and the third shift element C are open. As a result, the first ring gear shaft HR 1 is connected in a rotationally fixed manner to the stationary component designed as a housing G via the first switching unit SE 1 according to FIG. 2, and the first sun shaft SO 1 is connected in a rotationally fixed manner to the stationary component designed as a housing G according to FIG. 3. Via the second shift unit SE 2, the third ring gear shaft HR 3 is connected in a rotationally fixed manner to the stationary component designed as a housing G. In the present case, FIGS. 2 and 3 show these switching positions of the sliding sleeves SM 1, SM 2.The second gear G 2 is engaged by the first sliding sleeve SM 1 being displaced from the third shift position axially over the neutral position, i.e. over the second shift position, into the first shift position. In the second shift position of the first sliding sleeve SM 1, the first sliding sleeve SM 1 according to FIG. 2 is only in rotational engagement with the first ring gear shaft HR 1 and according to FIG. 3 is only in rotational engagement with the first sun shaft SO 1. In the neutral position of the first sliding sleeve SM 1, both shift elements A and B are open, so that the drive shaft An is decoupled from the differential DG. In the neutral position, the electric machine EM can synchronize the target gear.In a second gear G 2, the first shifting element A and the fourth shifting element D are closed, and the second shifting element B and the third shifting element C are open. As a result, the planetary set PS is locked via the first shift unit SE 1 by virtue of the first ring gear shaft HR 1 and the first sun shaft SO 1 being connected in a rotationally fixed manner according to FIG. 2 and the first sun shaft SO 1 and the first carrier shaft ST 1 being connected in a rotationally fixed manner according to FIG. 3. Via the second shift unit SE 2, the third ring gear shaft HR 3 is connected in a rotationally fixed manner to the stationary component designed as a housing G.The third gear G 3 is engaged by the first sliding sleeve SM 1 being displaced from the first shift position axially over the neutral position, i.e. over the second shift position, into the third shift position, and the second sliding sleeve SM 2 being displaced from the third shift position axially over the neutral position, i.e. over the second shift position, into the first shift position. In the second shift position of the second sliding sleeve SM 2, the second sliding sleeve SM 2 according to FIGS. 2 and 3 is only in rotational engagement with the housing G. In the neutral position of the second sliding sleeve SM 2, both shift elements C and D are open, so that the drive shaft An is decoupled from the differential DG.In a third gear G 3, the second shifting element B and the third shifting element C are closed, and the first shifting element A and the fourth shifting element D are open. As a result, the first ring gear shaft HR 1 is connected in a rotationally fixed manner to the stationary component designed as a housing G via the first switching unit SE 1 according to FIG. 2, and the first sun shaft SO 1 is connected in a rotationally fixed manner to the stationary component designed as a housing G according to FIG. 3. Via the second shift unit SE 2, the second ring gear shaft HR 2 is connected in a rotationally fixed manner to the stationary component designed as a housing G.The fourth gear G 4 is engaged by the first sliding sleeve SM 1 being displaced from the third shift position axially over the neutral position, i.e. over the second shift position, into the first shift position.In a fourth gear G 4, the first shifting element A and the third shifting element C are closed, and the second shifting element B and the fourth shifting element D are open. As a result, the planetary set PS is locked via the first shift unit SE 1 by virtue of the first ring gear shaft HR 1 and the first sun shaft SO 1 being connected in a rotationally fixed manner according to FIG. 2 and the first sun shaft SO 1 and the first carrier shaft ST 1 being connected in a rotationally fixed manner according to FIG. 3. Via the second shift unit SE 2, the second ring gear shaft HR 2 is connected in a rotationally fixed manner to the stationary component designed as a housing G.Reference numerals denote reference numerals100 Vehicle 101 First axle 102 Second axle R 1 Vehicle wheel R 2 Vehicle wheel R 3 Vehicle wheel R 4 Vehicle wheel An input shaft SG Transmission EM Electric machine EMS Stator of the electric machine EMR Rotor of the electric machine PS Planetary set SP Stepped planetary set Z 1 First gearwheel of a stepped planetary gearwheel Z 2 Second gearwheel of a stepped planetary gearwheel SO 1 First sun shaft SO 2 Second sun shaft HO 1 First ring gear shaft HO 2 Second ring gear shaft HO 3 Third ring gear shaft ST 1 First carrier shaft ST 2 Second carrier shaft G Housing R Axis of symmetry DG Differential D 1 Differential input shaft D 2 First differential output shaft D 3 Second differential output shaft 20 Differential cage 21 First output wheel 22 second output gear 23 compensating element 24 compensating element 30 first planetary set 31 sun gear of first planetary set 32 ring gear of first planetary set 33 carrier shaft of first planetary set 40 second planetary set 41 sun gear of second planetary set 42 ring gear of second planetary set 43 carrier shaft of second planetary set AK1 first actuator AK2 second actuator SE1 first shift unit SE2 second shift unit SM1 first sliding sleeve SM2 second sliding sleeve A first shift element B second shift element C third shift element D fourth shift element G1 first gear G2 second gear G3 third gear G4 fourth gear

Claims

Drive unit for a vehicle (100), comprising an electric machine (EM) and a transmission (SG) arranged coaxially thereto, which transmission is connected to the electric machine (EM) via a drive shaft (An), the transmission (SG) having • a first shift unit (SE1) having a first shift element (A) and a second shift element (B), • a second shift unit (SE2) having a third shift element (C) and a fourth shift element (D), • a planetary set (PS) having a plurality of planetary gears, a first sun shaft (SO1), a first ring gear shaft (HR1) and a first carrier shaft (ST1), • a stepped planetary set (SP) having a plurality of stepped planetary gears, a second sun shaft (SO2), a second ring gear shaft (HR2), a third ring gear shaft (HR3) and a second carrier shaft (ST2), and • a differential (DG) with a differential input shaft (D1) and two differential output shafts (D2, D3), • wherein a first gearwheel (Z1) of the respective stepped planetary gearwheel is in toothed engagement with the second sun shaft (SO2) and the second ring gear shaft (HR2), • wherein a second gearwheel (Z2) of the respective stepped planetary gearwheel is in toothed engagement with the third ring gear shaft (HR3), • wherein the second carrier shaft (ST2) is connected rotationally fixedly to the differential input shaft (D1), • wherein the planetary set (PS) is designed to be switchable and one of its three shafts is connected to the drive shaft (An) in a rotationally fixed manner, wherein another of its three shafts is connected to the second sun shaft (SO2) in a rotationally fixed manner, wherein another of its three shafts is switchable via the first switching unit (SE1), • wherein the planetary set (PS) is blocked in the closed state of the first switching element (A), • wherein one of the three shafts of the planetary set (PS) is connected to a stationary component in a rotationally fixed manner in the closed state of the second switching element (B), • wherein the second ring gear shaft (HR2) is connected to the stationary component in a rotationally fixed manner in the closed state of the third switching element (C), • wherein, in the closed state of the fourth shift element (D), the third ring gear shaft (HR 3) is connected to the stationary component in a rotationally fixed manner.Drive unit according to Claim 1, wherein the first sun shaft (SO1) is connected to the drive shaft (An) in a rotationally fixed manner, wherein the first carrier shaft (ST1) is connected to the second sun shaft (SO2) in a rotationally fixed manner, wherein the first ring gear shaft (HR1) is connected to the first sun shaft (SO1) in a rotationally fixed manner in the closed state of the first shift element (A) in order to block the planetary set (PS), wherein the first ring gear shaft (HR1) is connected to the stationary component in a rotationally fixed manner in the closed state of the second shift element (B).Drive unit according to Claim 1, wherein the first ring gear shaft (HR1) is connected to the drive shaft (An) in a rotationally fixed manner, wherein the first carrier shaft (ST1) is connected to the second sun shaft (SO2) in a rotationally fixed manner, wherein the first sun shaft (SO1) is connected to the first carrier shaft (ST1) in a rotationally fixed manner in the closed state of the first shift element (A) in order to block the planetary set (PS), wherein the first sun shaft (SO1) is connected to the stationary component in a rotationally fixed manner in the closed state of the second shift element (B).Drive unit according to one of the preceding claims, wherein the differential (DG) is designed as a bevel gear differential and is arranged at least partially radially stacked with the stepped planetary gear set (SP).Drive unit according to one of the preceding claims, wherein the drive shaft (An) is designed as a hollow shaft and one of the two differential output shafts (D2, D3) is axially guided at least by the electric machine (EM), the drive shaft (An) and the planetary set (PS).Drive unit according to one of the preceding claims, wherein all four shift elements (A, B, C, D) are designed as positively locking shift elements.Drive unit according to one of the preceding claims, wherein the respective shift unit (SE1, SE2) has in each case a single axially displaceable sliding sleeve (SM1, SM2) having in each case three shift positions.Drive unit according to one of the preceding claims, wherein the respective shift unit (SE1, SE2) has a neutral position between two gear positions.Method for setting four gears (G1, G2, G3, G4) for a drive unit according to one of the preceding claims, • wherein in a first gear (G1) the second shift element (B) and the fourth shift element (D) are closed and the first shift element (A) and the third shift element (C) are opened, • wherein in a second gear (G2) the first shift element (A) and the fourth shift element (D) are closed and the second shift element (B) and the third shift element (C) are opened, • wherein in a third gear (G3) the second shift element (B) and the third shift element (C) are closed and the first shift element (A) and the fourth shift element (D) are opened, • wherein, in a fourth gear (G4), the first shift element (A) and the third shift element (C) are closed and the second shift element (B) and the fourth shift element (D) are open.Vehicle (100) comprising at least one drive unit according to one of Claims 1 to 8.

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