WO2024074310A1

WO2024074310A1 - Transmission and drive device for a motor vehicle

Info

Publication number: WO2024074310A1
Application number: PCT/EP2023/076030
Authority: WO
Inventors: Stefan Beck; Matthias Reisch; Tamas Gyarmati; Eckhardt LÜBKE; Domenico Bartilucci
Original assignee: Zf Friedrichshafen Ag
Priority date: 2022-10-06
Filing date: 2023-09-21
Publication date: 2024-04-11
Also published as: DE102022210575A1

Abstract

The invention relates to a transmission for a motor vehicle, having • a first, second, and third planetary gear set, each planetary gear set having a first, second, and third element, and • a driveshaft, a first and second output shaft, and a first and second coupling shaft, wherein • one of the elements of the first planetary gear set is connected to the driveshaft for co-rotation therewith, another element of the first planetary gear set is connected to the first coupling shaft for co-rotation therewith, and another element of the first planetary gear set is connected to the second coupling shaft for co-rotation therewith, • one of the elements of the second planetary gear set is connected to the first couple shaft for co-rotation therewith, another element of the second planetary gear set is connected to a stationary component for co-rotation therewith, and another element of the second planetary gear set is connected to the first output shaft for co-rotation therewith, and • one of the elements of the third planetary gear set is connected to the second coupling shaft for co-rotation therewith, another element of the third planetary gear set is connected to the second output shaft for co-rotation therewith, and another element of the third planetary gear set is connected to a stationary component for co-rotation therewith.

Description

Transmission and drive device for a motor vehicle

The invention relates to a transmission for a motor vehicle having three planetary gear sets and five shafts, wherein one of the five shafts is designed as a drive shaft and is configured to be connected to a drive engine in a driving manner, and wherein two of the five shafts are designed as output shafts and are configured to be connected to a respective wheel of the motor vehicle in a driving manner. The invention further relates to a drive device with such a transmission and a motor vehicle with such a drive device.

For example, DE 102013215 877 A1 discloses an epicyclic gear for branching the drive power applied to a power input to a first and a second power output in conjunction with a reduction of the output speed to a speed level below the drive speed at the power input. The epicyclic gear comprises a first gear stage, which has a first sun gear, a first planetary gear set, a first planetary carrier and a first ring gear, a second gear stage, which has a second sun gear, a second planetary gear set, a second planetary carrier and a second ring gear, and a third planetary gear stage, which has a third sun gear, a third planetary gear set and a third planetary carrier. The first sun gear is set up as a power input, the first planetary carrier is coupled to the second sun gear in a rotationally fixed manner, the second planetary carrier is fixed in a stationary manner, the first ring gear is coupled to the third sun gear, the first power output takes place via the third gear stage, and the second power output takes place via the second ring gear of the second gear stage.

The object of the present invention is to create an alternative transmission which in particular has an improved power density and an improved efficiency. The transmission is intended to generate two approximately equal output torques from a drive torque, which are greater than the drive torque. The transmission is therefore intended to implement both a transmission function, i.e. a torque conversion, and a differential function. These objects are achieved by a transmission with the features of patent claim 1. Advantageous embodiments are the subject of the dependent claims, the following description and the figures.

A transmission according to the invention for a motor vehicle comprises a first planetary gear set, a second planetary gear set and a third planetary gear set, each planetary gear set having a first element, a second element and a third element, five shafts, namely a drive shaft for connecting the transmission to a drive engine of the motor vehicle, a first output shaft and a second output shaft each for connecting the transmission to a wheel of the motor vehicle, a first coupling shaft and a second coupling shaft each for the rotationally fixed connection of two elements of two planetary gear sets,

• wherein one of the elements of the first planetary gear set is connected in a rotationally fixed manner to the drive shaft, wherein another of the elements of the first planetary gear set is connected in a rotationally fixed manner to the first coupling shaft, wherein another of the elements of the first planetary gear set is connected in a rotationally fixed manner to the second coupling shaft,

• wherein one of the elements of the second planetary gear set is connected in a rotationally fixed manner to the first coupling shaft, wherein another of the elements of the second planetary gear set is connected in a rotationally fixed manner to a stationary component, wherein another of the elements of the second planetary gear set is connected in a rotationally fixed manner to the first output shaft,

• wherein one of the elements of the third planetary gear set is rotationally fixedly connected to the second coupling shaft, wherein another of the elements of the third planetary gear set is rotationally fixedly connected to the second output shaft, wherein another of the elements of the third planetary gear set is rotationally fixedly connected to a stationary component.

A "connection" of a device or an element to the gear means that the gear, in particular the corresponding shaft of the gear, is either directly connected to the device or the element, for example in a rotationally fixed manner, or indirectly connected, for example via at least one further component, in particular via at least one further shaft or gear. If two shafts are connected to one another in a rotationally fixed manner, they rotate they rotate together in one direction with one rotational speed. In particular, the connection can also be made via a switching element, which enables the device or element to be coupled and uncoupled with the corresponding shaft of the gearbox.

A "shaft" is not exclusively understood to mean, for example, a cylindrical, rotatably mounted gear element for transmitting torque, but rather also general connecting elements that connect individual components or elements to one another, in particular connecting elements that connect several elements to one another in a rotationally fixed manner. Two shafts that are connected to one another in a rotationally fixed manner can be formed in one piece.

A "stationary component" is a non-rotating component of the transmission. For example, the stationary component is designed as a housing or housing section of the transmission. Alternatively, the stationary component can be designed as a shaft fixed to the housing.

Thus, the first planetary gear set is or can be connected at least directly or indirectly to the drive machine via the drive shaft, and is connected to the second planetary gear set via the first coupling shaft and to the third planetary gear set via the second coupling shaft. Furthermore, the second planetary gear set is rotationally connected to the housing and to the first output shaft.

The second planetary gear set is or can be connected at least directly or indirectly to a first wheel of the motor vehicle via the first output shaft. The third planetary gear set is also connected in a rotationally fixed manner to the second output shaft. The third planetary gear set is or can be connected at least directly or indirectly to a second wheel of the motor vehicle via the second output shaft.

The speeds of the first coupling shaft and the second coupling shaft have different directions of rotation when the vehicle is travelling straight ahead. In addition, the torque on the two coupling shafts has different signs. In particular, the torque on the two coupling shafts has different amounts, so that there is an asymmetrical torque distribution. The advantage of this is that the first planetary gear set is used to generate a gear ratio. The drive shaft and the two output shafts have the same direction of rotation when the vehicle is driving straight ahead. As with any differential, depending on the vehicle operation, one of the two output shafts can rotate in the opposite direction to the drive rotation. The advantage is that the identical rotation directions of the drive shaft and the two output shafts reduce the transmission support torque, which means that the component load is lower. This can lead to cost and weight advantages in particular. Furthermore, not reversing the direction of rotation leads to less relative movement in the transmission and therefore potentially better efficiency.

For example, the drive machine is designed as an electric machine that can be operated as a drive motor to drive the vehicle and as a generator to recuperate electrical energy. For this purpose, the electric machine is electrically connected to an electrical energy storage device. The electric machine comprises a rotor and a stator, wherein the rotor is connected to a rotor shaft in a rotationally fixed manner. The rotor shaft of the electric machine is connected to the drive shaft at least directly or indirectly. For example, the rotor shaft of the electric machine is connected to the drive shaft via at least one further shaft, via several gears and/or via a traction device. The electric machine can be arranged on a common axis of rotation with the transmission and thus be designed coaxially to the drive shaft, in which case the rotor shaft is preferably connected to the drive shaft in a rotationally fixed manner. Alternatively, the electric machine can be designed axially parallel to the drive shaft, in which case the rotor shaft is indirectly connected to the drive shaft. Alternatively, the drive machine can be designed as an internal combustion engine with a crankshaft.

According to a preferred embodiment, the first element of the first planetary gear set is connected to the drive shaft in a rotationally fixed manner, wherein the second element of the first planetary gear set is connected to the second coupling shaft in a rotationally fixed manner, wherein the third element of the first planetary gear set is connected to the first coupling shaft in a rotationally fixed manner, wherein the first element of the second planetary gear set is connected to the first coupling shaft is connected in rotation, wherein the second element of the second planetary gear set is connected in rotation to a stationary component, wherein the third element of the second planetary gear set is connected in rotation to the first output shaft, wherein the first element of the third planetary gear set is connected in rotation to a stationary component, wherein the second element of the third planetary gear set is connected in rotation to the second output shaft, wherein the third element of the third planetary gear set is connected in rotation to the second coupling shaft. In this regard, reference is made to the embodiments according to Figures 3 to 6.

According to a preferred embodiment, the first element of the first planetary gear set is rotationally connected to the input shaft, the second element of the first planetary gear set is rotationally connected to the second coupling shaft, the third element of the first planetary gear set is rotationally connected to the first coupling shaft, the second element of the second planetary gear set is rotationally connected to a stationary component, the third element of the second planetary gear set is rotationally connected to the first output shaft, the first element of the third planetary gear set is rotationally connected to the second coupling shaft, the second element of the third planetary gear set is rotationally connected to the second output shaft, the third element of the third planetary gear set is rotationally connected to a stationary component. For this purpose, reference is made to the embodiment according to Figure 7.

According to a preferred embodiment, the second planetary gear set is arranged axially between the first planetary gear set and the third planetary gear set. Alternatively, the third planetary gear set is arranged axially between the first planetary gear set and the second planetary gear set. In particular, the first planetary gear set is designed in both cases to be arranged axially adjacent to the drive machine.

According to a preferred embodiment, two of the three planetary gear sets are arranged radially nested. In other words, the elements of the two Planetary gear sets are arranged axially overlapping in such a way that one of the two planetary gear sets is arranged on the outside and the other of the two planetary gear sets is arranged on the inside. This makes the transmission more compact, particularly in the axial direction. The first and second planetary gear sets are preferably arranged radially nested.

According to a preferred embodiment, one of the two coupling shafts or one of the two output shafts is formed in one piece with the elements of the respective planetary gear set connected to it. For example, a coupling shaft or an output shaft can be formed in one piece as an intermediate gear with two toothings, with an internal toothing of the intermediate gear forming a ring gear for a radially inner planetary gear set, with an external toothing of the intermediate gear forming a sun gear for a radially outer planetary gear set. Such an intermediate gear is also called a sun ring gear. Alternatively, a coupling shaft or an output shaft can have a toothing that forms a common ring gear for two planetary gear sets. Alternatively, a coupling shaft or an output shaft can have a toothing that forms a common sun gear for two planetary gear sets. Alternatively, a coupling shaft or an output shaft can form a common planet carrier.

According to a preferred embodiment, at least one of the planetary gear sets is designed as a minus planetary gear set, wherein the first element of the respective planetary gear set is designed as a sun gear, wherein the second element of the respective planetary gear set is designed as a planet carrier, wherein the third element of the respective planetary gear set is designed as a ring gear. Several planetary gears are rotatably mounted on the planet carrier and are in meshing engagement with the sun gear and the ring gear.

Alternatively, at least one of the planetary gear sets can be designed as a minus stepped planetary gear set, in which case the planet carrier then guides several stepped planetary gears in a rotatable manner. Each stepped planetary gear has two gears that are connected to one another in a rotationally fixed manner. In other words, each stepped planetary gear has two toothed sections that are connected to one another in a rotationally fixed manner, which have different diameter. One of the two toothed sections meshes with the sun gear and the other of the two toothed sections meshes with the ring gear. If the first element of the minus stepped planetary gear set is a sun gear, then the third element of the minus stepped planetary gear set is designed as a ring gear. If the first element of the minus stepped planetary gear set is a ring gear, then the third element of the minus stepped planetary gear set is designed as a sun gear. The second element of the minus stepped planetary gear set is designed as a planet carrier in both cases.

According to a preferred embodiment, at least one of the planetary gear sets is designed as a plus planetary gear set, wherein the first element of the respective planetary gear set is designed as a sun gear, wherein the second element of the respective planetary gear set is designed as a ring gear, wherein the third element of the respective planetary gear set is designed as a planet carrier. In a plus planetary gear set, the planet carrier guides at least one planetary gear pair, in which one planetary gear is in mesh with the inner sun gear and the other planetary gear is in mesh with the surrounding ring gear, and the planetary gears mesh with one another.

Alternatively, at least one of the planetary gear sets can be designed as a plus-stepped planetary gear set with two sun gears or as a plus-stepped planetary gear set with two ring gears. In a plus-stepped planetary gear set with two sun gears, the first and second elements of the plus-stepped planetary gear set are each designed as a sun gear, with the third element of the plus-stepped planetary gear set being designed as a planet carrier. In a plus-stepped planetary gear set with two ring gears, the first and second elements of the plus-stepped planetary gear set are each designed as a ring gear, with the third element of the plus-stepped planetary gear set being designed as a planet carrier.

According to a preferred embodiment, a constant gear ratio is arranged in the power flow in front of the drive shaft. The gear ratio is therefore designed as a pre-transmission. For example, the gear ratio is designed as a planetary gear set with sun gear, ring gear and planet carrier or as a spur gear stage with at least two gears that mesh with one another. If the gear ratio is designed as a planetary gear set, one of the elements of the planetary gear set is fixed to the housing, another of the elements is or can be connected to a shaft of the drive machine at least directly or indirectly, and another of the elements is connected to the drive shaft in a rotationally fixed manner. If the gear ratio is designed as a spur gear stage, the drive machine is arranged axially parallel to the transmission and thus also to the drive shaft and the two output shafts. Higher gear ratios can be achieved in the transmission using a gear ratio.

According to a preferred embodiment, a first switching element for switching a first gear and a second switching element for switching a second gear are arranged in the power flow in front of the drive shaft. A “switching element” is to be understood as a switchable device which has at least one open and one closed state, wherein in the open state two shafts connected to it can rotate freely, and wherein in the closed state the two shafts are connected to one another in a rotationally fixed manner. For example, the first and second switching elements together with a planetary gear set form a 2-speed assembly which is connected upstream of the three planetary gear sets of the transmission. The upstream planetary gear set has, for example, the elements sun gear, ring gear and planet carrier. The upstream planetary gear set is blocked via the first switching element. In other words, two elements of the upstream planetary gear set, for example the sun gear and the ring gear, are connected in a rotationally fixed manner so that the upstream planetary gear set rotates in a block and has a gear ratio of 1. One of the elements of the upstream planetary gear set, for example the sun gear, is connected to the housing in a rotationally fixed manner via the second switching element, so that a different gear ratio is set. The second switching element is therefore designed as a brake. In this context, a “brake” is understood to mean a switchable device which, when closed, connects a shaft of the upstream planetary gear set to a housing in a rotationally fixed manner, so that this shaft is then fixed in a stationary manner and thus prevented from rotating. When the The shaft is decoupled from the housing of the switching element, allowing the shaft to rotate freely. Each switching element can be switched by a respective actuator.

According to a preferred embodiment, a switching element is arranged between the two output shafts to generate a locking effect. This switching element can be designed as a frictional or positive switching element. For example, a positive switching element is designed as a claw clutch. A positive switching element can increase the efficiency of the transmission due to reduced drag losses. In particular, positive switching elements are more compact and designed to be efficient and have a cost advantage over frictional switching elements. However, slip operation, i.e. a limited locking effect under differential speed, is not possible with positive switching elements. For example, a frictional switching element comprises several plates or at least one conical friction surface. In the case of a frictional switching element, this can be actuated via an actuator or mechanically, in particular by using axial forces from helical gears. An actuator can be fixed to the housing or can be arranged so that it rotates.

A drive device according to the invention has a drive machine and a transmission according to the invention. The drive machine is preferably designed as an electric machine. Alternatively, the drive machine is designed as an internal combustion engine. The drive machine can be arranged coaxially or axially parallel to the drive shaft of the transmission. The drive power of the drive machine is fed into the transmission via the drive shaft and distributed to the two output shafts, with the respective output shaft being connected to a respective drive wheel of a drive axle of the vehicle.

A vehicle according to the invention comprises a drive device according to the invention. In particular, the vehicle is designed as an electric vehicle and has an electric drive axle with the drive device according to the invention. The above definitions as well as statements on technical effects, advantages and advantageous embodiments of the transmission according to the invention apply accordingly. also for the drive device according to the invention and for the vehicle according to the invention.

Advantageous embodiments of the invention, which are explained below, are shown in the drawings, wherein like elements are provided with the same reference numerals. They show:

Fig. 1 is a highly abstracted schematic view of a motor vehicle with a drive device according to the invention;

Fig. 2 is a highly abstracted schematic diagram of the drive device according to the invention;

Fig. 3 is a highly abstracted schematic view of the drive device according to the invention according to a first embodiment;

Fig. 4 is a highly abstracted schematic view of a drive device according to the invention according to a second embodiment;

Fig. 5 is a highly abstracted schematic view of a drive device according to the invention according to a third embodiment;

Fig. 6 is a highly abstracted schematic view of a drive device according to the invention according to a fourth embodiment;

Fig. 7 is a highly abstracted schematic view of a drive device according to the invention according to a fifth embodiment;

Fig. 8 is a highly abstracted schematic view of a drive device according to the invention according to a sixth embodiment;

Fig. 9 is a highly abstracted schematic view of a drive device according to the invention according to a seventh embodiment; Fig. 10 is a highly abstracted schematic view of a drive device according to the invention according to an eighth embodiment;

Fig. 11 is a highly abstracted schematic view of a drive device according to the invention according to a ninth embodiment;

Fig. 12 is a highly abstracted schematic view of a drive device according to the invention according to a tenth embodiment;

Fig. 13 is a highly abstracted schematic view of a plus planetary gear set;

Fig. 14 is a highly abstracted schematic view of a minus-stage planetary gear set;

Fig. 15 is a highly abstracted schematic view of a plus-step planetary gear set with two sun gears; and

Fig. 16 is a highly abstracted schematic view of a plus-step planetary gear set with two ring gears.

Fig. 1 shows a motor vehicle 100 with a first wheel axle 101 with two wheels R1, R2 and a second wheel axle 102 with two wheels R3, R4. In the present case, the first wheel axle 101 is designed as the rear drive axle of the motor vehicle 100 and is equipped with a drive device according to the invention, which has a single drive machine 2 designed as an electric machine and a transmission 1 designed as an epicyclic gear. The motor vehicle 100 is therefore designed as an electric vehicle. The drive device is arranged transversely to the longitudinal direction of the vehicle and is connected to the wheels R1, R2 of the first wheel axle 101 in a drivingly effective manner. In the present case, no further drive device is arranged on the second wheel axle 102, i.e. on the front axle of the vehicle 100, thereby saving costs, weight and installation space. Alternatively, the Drive device can also be arranged on the front axle of the motor vehicle 100 instead of on the rear axle. To implement an all-wheel drive system, a further drive device can be arranged on the second wheel axle 102 and can be connected to the wheels R3, R4 of this wheel axle 102 in a driving manner.

Fig. 2 shows a schematic diagram of the drive device according to Fig. 1. The transmission 1 of the drive device comprises a first planetary gear set P1, a second planetary gear set P2 and a third planetary gear set P3, each of which is graphically represented by a circle. Each planetary gear set P1, P2, P3 has a first element, a second element and a third element, each of which is indicated by three connection options on the respective planetary gear set P1, P2, P3. The transmission 1 also comprises five shafts, namely an input shaft WAn for connecting the transmission 1 to the drive machine 2, a first output shaft WAb1 and a second output shaft WAb2, each for connecting the transmission 1 to a wheel of the motor vehicle, as well as a first coupling shaft W1 and a second coupling shaft W2.

One of the elements of the first planetary gear set P1 is connected to the drive shaft WAn in a rotationally fixed manner. The first planetary gear set P1 is connected to the drive machine 2 in a drivingly effective manner via the drive shaft WAn. In other words, at least one further shaft, a gear, a switching element or the like can be arranged in the power flow between the drive machine 2 and the drive shaft WAn. Another of the elements of the first planetary gear set P1 is connected to the first coupling shaft W1 in a rotationally fixed manner. Another of the elements of the first planetary gear set P1 is connected to the second coupling shaft W2 in a rotationally fixed manner.

One of the elements of the second planetary gear set P2 is connected in a rotationally fixed manner to the first coupling shaft W1. The first planetary gear set P1 is therefore connected to the second planetary gear set P2 via the first coupling shaft W1. Another of the elements of the second planetary gear set P2 is connected in a rotationally fixed manner to a stationary component of the transmission 1 designed as a housing G. Another of the elements of the second planetary gear set P2 is connected in a rotationally fixed manner to the first output shaft WAb1. One of the elements of the third planetary gear set P3 is connected to the second coupling shaft W2. The first planetary gear set P1 is therefore connected to the third planetary gear set P3 via the second coupling shaft W2. Another of the elements of the third planetary gear set P3 is connected to the second output shaft WAb2. Another of the elements of the third planetary gear set P3 is connected to a stationary component of the transmission 1 designed as a housing G. In particular, the second and third planetary gear sets P2, P3 are connected to the same housing section.

The speeds of the first coupling shaft W1 and the second coupling shaft W2 have different directions of rotation when the vehicle is driving straight ahead. In addition, the torque on the two coupling shafts W1, W2 has different signs. In particular, the torque on the two coupling shafts W1, W2 has different amounts, so that there is an asymmetrical torque distribution. The advantage of this is that the first planetary gear set P1 is used to generate a gear ratio. The drive shaft WAn and the two output shafts WAb1, WAb2 have the same direction of rotation when the vehicle is driving straight ahead. As with any differential, one of the two output shafts WAb1, WAb2 can rotate in the opposite direction to the drive direction of rotation depending on how the vehicle is being operated. The advantage is that the identical directions of rotation of the drive shaft WAn and the two output shafts WAb1, WAb2 reduce the transmission support torque, which reduces the load on the components. This can lead in particular to cost and weight advantages. Furthermore, the omission of a reversal of the direction of rotation leads to less relative movement in gear unit 1 and thus to a potentially better efficiency.

Fig. 3 shows schematically the drive device with the transmission 1 according to a first embodiment. The advantages of this first embodiment are a good efficiency, low wheel torques and a wide gear ratio range of the transmission 1. The transmission 1 comprises the first planetary gear set P1, the second planetary gear set P2 and the third planetary gear set P3, wherein each of the three planetary gear sets P1, P2, P3 has a first element E11, E21, E31, a second element E12, E22, E32 and a third element E13, E23, E33. In the present case, the first element E11, E21, E31 of the respective planetary gear set P1, P2, P3 is designed as a sun gear, the second element E12, E22, E32 of the respective planetary gear set P1, P2, P3 is designed as a planet carrier, the third element E13, E23, E33 of the respective planetary gear set P1, P2, P3 is designed as a ring gear. Each planet carrier carries at least one planetary gear which meshes with the sun gear and the ring gear of the respective planetary gear set P1, P2, P3. Each of the three planetary gear sets P1, P2, P3 is therefore designed as a conventional minus planetary gear set. Alternatively, at least one of the three planetary gear sets can be designed as a conventional plus planetary gear set, minus stepped planetary gear set, plus stepped planetary gear set with two sun gears or plus stepped planetary gear set with two ring gears.

The first element E11 of the first planetary gear set P1 is connected in a rotationally fixed manner to the drive shaft WAn, the second element E12 of the first planetary gear set P1 is connected in a rotationally fixed manner to the second coupling shaft W2, and the third element E13 of the first planetary gear set P1 is connected in a rotationally fixed manner to the first coupling shaft W1. The drive shaft WAn is connected in this case to the drive machine 2. Alternatively, further elements, in particular shafts, gears, switching elements or other devices, can be arranged in the power flow between the drive machine 2 and the drive shaft WAn. For example, the power flow between the drive machine 2 and the drive shaft WAn can be interrupted by such a switching element.

The first element E21 of the second planetary gear set P2 is connected in a rotationally fixed manner to the first coupling shaft W1, wherein the second element E22 of the second planetary gear set P2 is connected in a rotationally fixed manner to a stationary component designed as a housing G, and wherein the third element E23 of the second planetary gear set P2 is connected in a rotationally fixed manner to the first output shaft WAb1.

The first element E31 of the third planetary gear set P3 is connected in a rotationally fixed manner to a stationary component designed as a housing G, whereby the second element E32 of the third planetary gear set P3 is connected in a rotationally fixed manner to the second output shaft WAb2. and wherein the third element E33 of the third planetary gear set P3 is rotationally fixedly connected to the second coupling shaft W2.

Thus, the second element E22 of the second planetary gear set P2 and the first element E31 of the third planetary gear set P3 are connected to the housing G. Furthermore, the first coupling shaft W1 connects the third element E13 of the first planetary gear set P1 to the first element E21 of the second planetary gear set P2, whereby the second coupling shaft W2 connects the second element E12 of the first planetary gear set P1 to the third element E33 of the third planetary gear set P3. The connection of the second element E12 of the first planetary gear set P1 is arranged on the side of the first planetary gear set P1 facing away from the drive machine 2. The advantage of this is that the first planetary gear set P1 does not have to be converted into a large pot.

The second planetary gear set P2 is arranged axially between the first planetary gear set P1 and the third planetary gear set P3, with the first planetary gear set P1 axially adjacent to the drive machine 2. This gives the drive device a compact design. All planetary gear sets P1, P2, P3 are arranged on one side next to the drive machine 2, as a result of which the oil chamber of the transmission 1 can be made narrower, so that oil suction when cornering is less critical. Furthermore, all three planetary gear sets P1, P2, P3 are arranged on a common axis of rotation R. The drive machine 2 is arranged coaxially to the axis of rotation R. The drive shaft WAn is designed as a hollow shaft, with the second output shaft WAb2 extending axially through the drive shaft WAn and the drive machine 2. The respective output shaft WAb1, WAb2 is connected in a rotationally fixed manner to a respective wheel of the motor vehicle.

The respective connection on the second and third element E32, E33 of the third planetary gear set P3 is arranged axially in the direction of the second planetary gear set P2. The connection on the first element E31 of the third planetary gear set P3 is arranged axially in the opposite direction, i.e. away from the second planetary gear set P2, but then runs around the third planetary gear set P3 in the direction of the second planetary gear set P2. Fig. 4 shows a second embodiment of the drive device according to the invention. The drive device according to Fig. 4 essentially corresponds to the drive device according to Fig. 3, with one difference between these two embodiments being the arrangement of the first and second planetary gear sets P1, P2. The advantage of this second embodiment over the first embodiment is a short axial length of the transmission 1. In the present case, the first and second planetary gear sets P1, P2 are arranged radially nested, with the first planetary gear set P1 being arranged radially on the inside and the second planetary gear set P2 being arranged radially on the outside. The first planetary gear set P1 is therefore arranged closer to the axis of rotation R than the second planetary gear set P2. The elements E11, E12, E13 of the first planetary gear set P1 and the elements E21, E22, E23 of the second planetary gear set P2 overlap in the axial direction. The first coupling shaft W1 is designed as an intermediate gear with an internal toothing and an external toothing and connects the first planetary gear set P1 and the second planetary gear set P2. In other words, the third element E13 of the first planetary gear set P1, the first element E21 of the second planetary gear set P2 and the first coupling shaft W1 are designed as a single piece as a common component. The internal toothing of the intermediate gear forms a ring gear for the radially inner first planetary gear set P1. The external toothing of the intermediate gear forms a sun gear for the radially outer second planetary gear set P2. The intermediate gear makes the transmission 1 more compact and lighter. Otherwise, the embodiment according to Fig. 4 corresponds to the embodiment according to Fig. 3, to which reference is made.

Fig. 5 shows a third embodiment of the drive device according to the invention. The drive device according to Fig. 5 corresponds essentially to the drive device according to Fig. 3, with a difference between these two embodiments being the arrangement of the connections on the third planetary gear set P3. In the present case, the connection on the first element E31 of the third planetary gear set P3 is arranged axially in the direction of the second planetary gear set P2. The connection on the third element E33 of the third planetary gear set P3 is arranged axially in the opposite direction, i.e. away from the second planetary gear set P2. Furthermore, the connection on the second element E32 of the third planetary gear set P3 is arranged axially in Direction of the second planetary gear set P2, but then runs in the opposite direction around the third planetary gear set P3. Otherwise, the embodiment according to Fig. 5 corresponds to the embodiment according to Fig. 3, to which reference is made.

Fig. 6 shows a fourth embodiment of the drive device according to the invention. The drive device according to Fig. 6 corresponds essentially to the drive device according to Fig. 3, with a difference between these two embodiments being the arrangement of the second and third planetary gear sets P2, P3. In the present case, the third planetary gear set P3 is arranged axially between the first planetary gear set P1 and the second planetary gear set P2. This can result in advantages in the arrangement of the transmission 1 in the housing. Otherwise, the embodiment according to Fig. 6 corresponds to the embodiment according to Fig. 3, to which reference is made.

Fig. 7 shows a fifth embodiment of the drive device according to the invention. The drive device according to Fig. 7 essentially corresponds to the drive device according to Fig. 3, with a difference between these two embodiments being the connection of the third planetary gear set P3. The advantages of this fifth embodiment are good efficiency, low gear set torques and low component loading of the transmission 1. In the present case, the first element E11 of the first planetary gear set P1 is connected in a rotationally fixed manner to the drive shaft WAn, the second element E12 of the first planetary gear set P1 is connected in a rotationally fixed manner to the second coupling shaft W2, the third element E13 of the first planetary gear set P1 is connected in a rotationally fixed manner to the first coupling shaft W1. The first element E21 of the second planetary gear set P2 is connected in a rotationally fixed manner to the first coupling shaft W1, the second element E22 of the second planetary gear set P2 being connected in a rotationally fixed manner to a stationary component designed as a housing G, the third element E23 of the second planetary gear set P2 being connected in a rotationally fixed manner to the first output shaft WAb1. Furthermore, the first element E31 of the third planetary gear set P3 is connected in a rotationally fixed manner to the second coupling shaft W2, the second element E32 of the third planetary gear set P3 is connected in a rotationally fixed manner to the second output shaft WAb2, the third element E33 of the third planetary gear set P3 is connected in a rotationally stable manner to a stationary component designed as a housing G. Otherwise, the embodiment according to Fig. 7 corresponds to the embodiment according to Fig. 3, to which reference is made.

Fig. 8 shows a sixth embodiment of the drive device according to the invention. The drive device according to Fig. 8 essentially corresponds to the drive device according to Fig. 3, with a difference between these two embodiments being the arrangement of a constant gear ratio in the power flow between the drive machine 2 and the drive shaft WAn. In the present case, this pre-transmission is designed as a fourth planetary gear set P4 and comprises a first element E41 designed as a sun gear, a second element E42 designed as a planet carrier and a third element E43 designed as a ring gear. The first element E41 of the fourth planetary gear set P4 is connected in a rotationally fixed manner to the stationary component designed as a housing G. The second element E42 of the fourth planetary gear set P4 is connected in a rotationally fixed manner to the drive shaft WAn. The third element E43 of the fourth planetary gear set P4 is drive-effectively connected to the drive machine 2. Alternatively, the connection of the fourth planetary gear set P4 can also be different, wherein one of the elements E41, E42, E43 of the fourth planetary gear set P4 is connected to the housing G in a rotationally fixed manner, another of the elements E41, E42, E43 of the fourth planetary gear set P4 is drivingly effective, i.e. indirectly or directly connected or connectable, to the drive machine 2, and another of the elements E41, E42, E43 of the fourth planetary gear set P4 is rotationally fixedly connected to the drive shaft WAn. The advantage of this pre-transmission designed as a planetary gear set is that higher transmission ratios can be achieved with the transmission 1. Otherwise, the embodiment according to Fig. 8 corresponds to the embodiment according to Fig. 3, to which reference is made.

Fig. 9 shows a seventh embodiment of the drive device according to the invention. The drive device according to Fig. 9 corresponds essentially to the drive device according to Fig. 3, with a difference between these two embodiments being the arrangement of a constant gear ratio in the power flow between the drive machine 2 and the drive shaft WAn. In the present case, This pre-transmission is designed as a spur gear stage ST and comprises a first gear Z1, which is drivingly connected to the drive machine 2, and a second gear Z2, which is rotationally connected to the drive shaft WAn. The diameters of the two gears Z1, Z2 of the spur gear stage ST can be used to set an axial distance of the drive machine 2 from the axis of rotation R. The drive machine 2 is therefore arranged axially parallel to the drive shaft WAn and to the two output shafts WAb1, WAb2. The advantage of this pre-transmission designed as a spur gear stage ST is that higher gear ratios can be achieved with the transmission 1. Otherwise, the embodiment according to Fig. 9 corresponds to the embodiment according to Fig. 3, to which reference is made.

Fig. 10 shows an eighth embodiment of the drive device according to the invention. The drive device according to Fig. 10 corresponds essentially to the drive device according to Fig. 3, with a difference between these two embodiments being the arrangement of a switching element S for generating a locking effect between the two output shafts WAb1, WAb2. In the present case, the switching element S is designed as a frictional switching element and generates a torque between the two output shafts WAb1, WAb2 in a partially closed state. In a fully closed state of the switching element S, the two output shafts WAb1, WAb2 are connected to one another in a rotationally fixed manner via the switching element S. In a fully open state of the switching element S, no torque is transmitted between the two output shafts WAb1, WAb2 via the switching element S. For example, the switching element S can have one or more friction surfaces acting in parallel. Alternatively, the switching element S can have one or more cone-shaped friction surfaces. A transmission 1 with such a limited-slip differential enables sporty driving in particular. Otherwise, the embodiment according to Fig. 10 corresponds to the embodiment according to Fig. 3, to which reference is made.

Fig. 11 shows a ninth embodiment of the drive device according to the invention. The drive device according to Fig. 11 corresponds essentially to the drive device according to Fig. 3, with a difference between these two embodiments in the arrangement of a switching element S for generating a There is a locking effect between the two output shafts WAb1, WAb2. In the present case, the switching element S is designed as a positive-locking switching element and, in a closed state, generates a locking torque between the two output shafts WAb1, WAb2 by torsionally connecting the two output shafts WAb1, WAb2. In an open state of the switching element S, no locking torque is generated between the two output shafts WAb1, WAb2. For example, the switching element S can have several positive-locking claws. A transmission 1 with such a limited-slip differential particularly supports traction when driving off-road. Otherwise, the embodiment according to Fig. 11 corresponds to the embodiment according to Fig. 3, to which reference is made.

Fig. 12 shows a tenth embodiment of the drive device according to the invention. The drive device according to Fig. 12 essentially corresponds to the drive device according to Fig. 8, with a difference between these two embodiments in the arrangement of a first shifting element A for shifting a first gear and a second shifting element B for shifting a second gear in the power flow between the drive machine 2 and the drive shaft WAn. In the present case, both shifting elements A, B are designed as frictional shifting elements, for example as multi-plate clutches, and enable power shifting. When the first shifting element A is closed and the second shifting element B is open, the first element E41 of the fourth planetary gear set P4 is connected to the housing G in a rotationally fixed manner and a first gear ratio is set. When the first switching element A is open and the second switching element B is closed, the fourth planetary gear set P4 is locked by connecting the first element E41 of the fourth planetary gear set P4 and the third element E43 of the fourth planetary gear set P4 in a rotationally fixed manner, thereby setting a second gear ratio. The advantage of such an upstream 2-speed switching device is that it enables high gear ratios at high top speeds. Otherwise, the embodiment according to Fig. 12 corresponds to the embodiment according to Fig. 8, to which reference is made. Figures 13 to 16 show different designs of planetary gear sets. At least one of the planetary gear sets of the transmission according to the invention can be designed as a conventional plus planetary gear set, minus stepped planetary gear set, plus stepped planetary gear set with two sun gears or plus stepped planetary gear set with two ring gears instead of as a conventional minus planetary gear set.

Figure 13 shows a plus planetary gear set. The first element E1 of the plus planetary gear set is designed as a sun gear, the second element E2 of the plus planetary gear set is designed as a ring gear, and the third element E3 of the plus planetary gear set is designed as a planet carrier. The planet carrier of the plus planetary gear set guides at least one planetary gear pair, consisting of a first planetary gear PR1 and a second planetary gear PR2. The first planetary gear PR1 meshes with the inner sun gear and the second planetary gear PR2 meshes with the surrounding ring gear. Furthermore, the two planetary gears PR1, PR2 of a planetary gear pair also mesh with each other.

Figure 14 shows a minus stepped planetary gear set. The first element E1 of the minus stepped planetary gear set is designed as a sun gear in the present case and can alternatively be designed as a ring gear. The second element E2 of the minus stepped planetary gear set is designed as a planet carrier. The third element E3 of the minus stepped planetary gear set is designed as a ring gear in the present case and can be designed as a sun gear if the first element E1 of the minus stepped planetary gear set is a ring gear. The planet carrier of the minus stepped planetary gear set guides at least one stepped planetary gear consisting of a first gear ZR1 and a second gear ZR2, the two gears ZR1, ZR2 being connected to one another in a rotationally fixed manner and as one piece. In the present case, the first gear ZR1 of the stepped planetary gear has a smaller diameter than the second gear ZR2 of the stepped planetary gear. The first gear ZR1 of the stepped planetary gear meshes with the inner sun gear and the second gear ZR2 of the stepped planetary gear meshes with the surrounding ring gear. Figure 15 shows a plus stepped planetary gear set with two sun gears. The first element E1 of the plus stepped planetary gear set is designed as the first sun gear. The second element E2 of the plus stepped planetary gear set is designed as the second sun gear. The third element E3 of the plus stepped planetary gear set is designed as a planet carrier. The planet carrier of the plus stepped planetary gear set guides at least one stepped planetary gear, consisting of a first gear ZR1 and a second gear ZR2, wherein the two gears ZR1, ZR2 are connected to one another in a rotationally fixed manner and as a single piece. In the present case, the first gear ZR1 of the stepped planetary gear has a larger diameter than the second gear ZR2 of the stepped planetary gear. The first gear ZR1 of the stepped planetary gear meshes with the first sun gear and the second gear ZR2 of the stepped planetary gear meshes with the second sun gear.

Figure 16 shows a plus stepped planetary gear set with two ring gears. The first element E1 of the plus stepped planetary gear set is designed as a first ring gear. The second element E2 of the plus stepped planetary gear set is designed as a second ring gear. The third element E3 of the plus stepped planetary gear set is designed as a planet carrier. The planet carrier of the plus stepped planetary gear set guides at least one stepped planetary gear, consisting of a first gear ZR1 and a second gear ZR2, wherein the two gears ZR1, ZR2 are connected to one another in a rotationally fixed manner and as a single piece. In the present case, the first gear ZR1 of the stepped planetary gear has a larger diameter than the second gear ZR2 of the stepped planetary gear. The first gear ZR1 of the stepped planetary gear meshes with the first ring gear and the second gear ZR2 of the stepped planetary gear meshes with the second ring gear.

Reference symbols

1 gearbox

2 Drive machine

W1 first coupling shaft

W2 second coupling shaft

WAn drive shaft

WAb1 first output shaft

WAb2 second output shaft

G Housing

A first switching element

B second switching element

S Switching element

R rotation axis

P1 first planetary gear set

E11 first element of the first planetary gear set

E12 second element of the first planetary gear set

E13 third element of the first planetary gear set

P2 second planetary gear set

E21 first element of the second planetary gear set

E22 second element of the second planetary gear set

E23 third element of the second planetary gear set

P3 third planetary gear set

E31 first element of the third planetary gear set

E32 second element of the third planetary gear set

E33 third element of the third planetary gear set

P4 fourth planetary gear set

E41 first element of the fourth planetary gear set

E42 second element of the fourth planetary gear set

E43 third element of the fourth planetary gear set

E1 first element

E2 second element

E3 third element PR1 first planetary gear

PR2 second planetary gear

ZR1 first gear of the stepped planetary gear

ZR2 second gear of the stepped planetary gear

ST spur gear stage

Z1 first gear of the spur gear stage

Z2 second gear of the spur gear stage

100 Motor vehicle

101 first wheel axle

102 second wheel axle

R1 Wheel

R2 Wheel

R3 Wheel

R4 Wheel

Claims

Patent claims

1 . Transmission (1 ) for a motor vehicle (100), comprising

• a first planetary gear set (P1), a second planetary gear set (P2) and a third planetary gear set (P3), each planetary gear set (P1, P2, P3) having a first element (E11, E21, E31), a second element (E12, E22, E32) and a third element (E13, E23, E33),

• a drive shaft (WAn) for connecting the transmission (1) to a drive engine (2) of the motor vehicle (100),

• a first output shaft (WAb1) and a second output shaft (WAb2), each for connecting the transmission (1) to a wheel (R1, R2) of the motor vehicle (100),

• a first coupling shaft (W1) and a second coupling shaft (W2) each for the rotationally fixed connection of two elements of two planetary gear sets (P1, P2, P3),

• wherein one of the elements (E11, E21, E31) of the first planetary gear set (P1) is connected in a rotationally fixed manner to the drive shaft (WAn), wherein another of the elements (E11, E21, E31) of the first planetary gear set (P1) is connected in a rotationally fixed manner to the first coupling shaft (W1), wherein another of the elements (E11, E21, E31) of the first planetary gear set (P1) is connected in a rotationally fixed manner to the second coupling shaft (W2),

• wherein one of the elements (E12, E22, E32) of the second planetary gear set (P2) is connected in a rotationally fixed manner to the first coupling shaft (W1), wherein another of the elements (E12, E22, E32) of the second planetary gear set (P2) is connected in a rotationally fixed manner to a stationary component, wherein another of the elements (E12, E22, E32) of the second planetary gear set (P2) is connected in a rotationally fixed manner to the first output shaft (WAb1),

• wherein one of the elements (E13, E23, E33) of the third planetary gear set (P3) is rotationally fixedly connected to the second coupling shaft (W2), wherein another of the elements (E13, E23, E33) of the third planetary gear set (P3) is rotationally fixedly connected to the second output shaft (WAb2), wherein another of the elements (E13, E23, E33) of the third planetary gear set (P3) is rotationally fixedly connected to a stationary component.

2. Transmission according to claim 1,

• wherein the first element (E11) of the first planetary gear set (P1) is rotationally connected to the drive shaft (WAn), wherein the second element (E12) of the first planetary gear set (P1) is rotationally connected to the second coupling shaft (W2), wherein the third element (E13) of the first planetary gear set (P1) is rotationally connected to the first coupling shaft (W1),

• wherein the first element (E21) of the second planetary gear set (P2) is rotationally connected to the first coupling shaft (W1), wherein the second element (E22) of the second planetary gear set (P2) is rotationally connected to a stationary component, wherein the third element (E23) of the second planetary gear set (P2) is rotationally connected to the first output shaft (WAb1),

• wherein the first element (E31) of the third planetary gear set (P3) is rotationally connected to a stationary component, wherein the second element (E32) of the third planetary gear set (P3) is rotationally connected to the second output shaft (WAb2), wherein the third element (E33) of the third planetary gear set (P3) is rotationally connected to the second coupling shaft (W2).

3. Transmission (1) according to claim 1,

• wherein the first element (E31) of the third planetary gear set (P3) is rotationally connected to the second coupling shaft (W2), wherein the second element (E32) of the third planetary gear set (P3) is rotationally connected to the second output shaft (WAb2), wherein the third element (E33) of the third planetary gear set (P3) is rotationally connected to a stationary component.

4. Transmission according to one of the preceding claims, wherein the second planetary gear set (P2) is arranged axially between the first planetary gear set (P1) and the third planetary gear set (P3).

5. Transmission according to one of claims 1 to 3, wherein the third planetary gear set (P3) is arranged axially between the first planetary gear set (P1) and the second planetary gear set (P2).

6. Transmission (1) according to one of claims 1 to 3, wherein two of the three planetary gear sets (P1, P2, P3) are arranged radially nested.

7. Transmission (1) according to one of the preceding claims, wherein one of the two coupling shafts (W1, W2) or one of the two output shafts (WAb1, WAb2) is formed in one piece with the elements of the respective planetary gear set (P1, P2, P3) connected thereto.

8. Transmission (1) according to one of the preceding claims, wherein at least one of the planetary gear sets (P1, P2, P3) is designed as a minus planetary gear set, wherein the first element (E11, E21, E31) of the respective planetary gear set (P1, P2, P3) is designed as a sun gear, wherein the second element (E12, E22, E32) of the respective planetary gear set (P1, P2, P3) is designed as a planet carrier, wherein the third element (E13, E23, E33) of the respective planetary gear set (P1, P2, P3) is designed as a ring gear.

9. Transmission (1) according to one of the preceding claims, wherein at least one of the planetary gear sets (P1, P2, P3) is designed as a plus planetary gear set, wherein the first element (E11, E21, E31) of the respective planetary gear set (P1, P2, P3) is designed as a sun gear, wherein the second element (E12, E22, E32) of the respective planetary gear set (P1, P2, P3) is designed as a ring gear, wherein the third element (E13, E23, E33) of the respective planetary gear set (P1, P2, P3) is designed as a planet carrier.

10. Transmission (1) according to one of the preceding claims, wherein a constant gear ratio is arranged in the power flow in front of the drive shaft (WAn).

11. Transmission (1) according to one of the preceding claims, wherein a first shifting element (A) for shifting a first gear and a second shifting element (B) for shifting a second gear are arranged in the power flow in front of the drive shaft (WAn).

12. Transmission (1) according to one of the preceding claims, wherein a switching element (S) for generating a locking effect is arranged between the two output shafts (WAb1, WAb2).

13. Drive device with a drive machine (2) and a transmission (1) according to one of claims 1 to 12.

14. Motor vehicle (100) with a drive device according to claim 13.