Patent ID: 12247650

In the figures identical or functionally identical elements are provided with the same reference sign.

DETAILED DESCRIPTION

FIG.1shows an electric drive system10for a motor vehicle, in particular for an automobile, in a schematic representation. Thus, the motor vehicle, in its completely produced state, has the electric drive system10, by means of which the motor vehicle can be driven electrically, in particular purely electrically. The motor vehicle has at least or exactly two axles arranged in the vehicle longitudinal direction following each other and thus arranged one behind the other. The respective axle has at least or exactly two wheels, also referred to as vehicle wheels, wherein the respective wheels of the respective axle are arranged on sides of the motor vehicle that are opposite each other in the vehicle transverse direction. For example, the drive system10is assigned to at least one of the axles or to exactly one of the axles so that at least or only the wheels of the axle, to which the electric drive system10is assigned, can be driven by means of the electric drive system10. The wheels driven by means of the electric drive system10are also referred to as drive wheels. The drive wheels are represented inFIG.1particularly schematically and referred to with12and14. The motor vehicle can be driven electrically, in particular purely electrically, by in particular purely electrical driving of the drive wheels12and14by means of the drive system10.

The drive system10has a first electric machine16, which has a first stator18and a first rotor20. The rotor20can be driven by means of the stator18and therefore rotated around a first machine rotational axis in relation to the stator18. The drive system10has a housing22, represented particularly schematically inFIG.1, which is also referred to as a housing device or housing element. In this case, the rotor20can be rotated around the first machine rotational axis in relation to the stator18and in relation to the housing22.

The drive system10further comprises a second electric machine24, which has a second stator26and a second rotor28. The rotor28can be driven by means of the stator26and as a result rotated around a second machine rotational axis in relation to the stator26and in relation to the housing22. Preferably, the electric machines16and24and thus their rotors20and28are arranged coaxially to each other, even though this is represented differently inFIG.1for reasons of space. As the electric machines16and24and thus their rotors20and28are preferably arranged coaxially to each other, the machine rotational axes coincide. The electric machine16can provide first torques via its rotor20, which are illustrated by an arrow21. The second electric machine24can provide second torques via its rotor28, which are illustrated by an arrow29inFIG.1.

The drive system10has a planetary transmission30, which has a first planetary gear set32and a second planetary gear set34. The planetary gear sets32and34are also simply referred to as planetary sets. Furthermore, the planetary transmission30has a first input shaft36and a second input shaft38. Furthermore, the planetary transmission30has a first output shaft40and a second output shaft42. The first input shaft36is formed to introduce the first torques, originating from the electric machine16, i.e., from the first electric machine16via the rotor20and thus provided by the rotor20, into the planetary transmission30. The second input shaft38is formed to introduce the second torques, originating from the second electric machine24, i.e., from the electric machine24via the rotor28and thus provided by the rotor28, into the planetary transmission30. The first output shaft40is formed to discharge third torques, which, for example, result from the first torques and/or second torques introduced into the planetary transmission30, from the planetary transmission30, wherein the third torques are represented inFIG.1by an arrow41. The second output shaft42is formed to discharge fourth torques, which, for example, result from the first torques and/or second torques introduced into the planetary transmission30, from the planetary transmission30, wherein the fourth torques are represented inFIG.1by an arrow43.

The first planetary gear set32has a first sum shaft S1, a first differential shaft D1, and a second differential shaft D2. The second planetary gear set34has a second sum shaft S2, a third differential shaft D3, and a fourth differential shaft D4. In this case, the second input shaft38is connected in a rotationally fixed manner with the first differential shaft D1, in particular permanently. The first output shaft40is connected in a rotationally fixed manner with the first sum shaft S1, in particular permanently. Furthermore, the first output shaft40is connected in a rotationally fixed manner with the fourth differential shaft D4, in particular permanently. The second output shaft42is connected in a rotationally fixed manner with the second differential shaft D2, in particular permanently. Furthermore, it is provided in the exemplary embodiment shown inFIG.1that the second output shaft42is connected in a rotationally fixed manner with the second sum shaft S2, in particular permanently, such that in the exemplary embodiment shown inFIG.1, the second differential shaft D2is connected in a rotationally fixed manner with the second sum shaft S2, in particular permanently.

In order to be able to achieve a particularly advantageous drivability of the motor vehicle in a manner particularly favorable to installation space, the planetary transmission30has a third planetary gear set44, which is also referred to as a third planetary set. The third planetary gear set44has a third sum shaft S3, a fifth differential shaft D5, and a sixth differential shaft D6. In this case, the first input shaft36is connected in a rotationally fixed manner with the third sum shaft S3, in particular permanently. Furthermore, the third differential shaft D3is connected in a rotationally fixed manner with the fifth differential shaft D5, in particular permanently. In the exemplary embodiment shown inFIG.1, the input shaft36is connected in a rotationally fixed manner with the rotor20, in particular permanently. Furthermore, in the exemplary embodiment shown inFIG.1, it is provided that the input shaft38is connected in a rotationally fixed manner with the rotor28, in particular permanently.

The electric drive system10, in particular the planetary transmission30, has a first switching element SE1which is formed to connect the fourth differential shaft D4with the sixth differential shaft D6in a rotationally fixed manner. Furthermore, the electric drive system10, in particular the planetary transmission30, has a second switching element SE2, which is formed to connect the third differential shaft D3, and thus in the exemplary embodiment shown inFIG.1, the fifth differential shaft D5, with the sixth differential shaft D6in a rotationally fixed manner.

FIG.1shows a first state of the electric drive system10, in particular of the planetary transmission30, wherein the first state for example is a first switching state. In the first state, the switching element SE1is closed, while the switching element SE2is open, such that in the first state the fourth differential shaft D4is connected in a rotationally fixed manner with the sixth differential shaft D6by means of the first switching element SE1, while the third differential shaft D3is not connected in a rotationally fixed manner with the sixth differential shaft D6, such that, for example, the third differential shaft D3and the sixth differential shaft D6can rotate in relation to each other, in particular around a first planetary gear set rotational axis of the planetary gear set32and/or around a second planetary gear set rotational axis of the second planetary gear set34and/or around a third planetary gear set rotational axis of the third planetary gear set44. In the exemplary embodiment shown inFIG.1, the planetary gear sets32,34and44are arranged coaxially to each other, such that the aforementioned planetary gear set rotational axes coincide. Furthermore, it is conceivable that the planetary gear sets32,34, and44and thus the planetary transmission30are arranged coaxially to the rotors20and28, such that the planetary gear set rotational axes coincide and such that the planetary gear set rotational axes coincide with the machine rotational axes, which similarly coincide.

FIG.2shows a second state of the electric drive system10, in particular of the planetary transmission30. The second state is also referred to as a second switching state. In the second state, the switching element SE1is opened, while the second switching element SE2is closed. Thus, in the second state the third differential shaft D3and the sixth differential shaft D6are connected with each other by means of the second switching element SE2in a rotationally fixed manner, while the fourth differential shaft D4and the sixth differential shaft D6are not connected with each other in a rotationally fixed manner but can rotate in relation to each other around the respective planetary gear rotational axis.

In the exemplary embodiment shown in the figures, the first differential shaft D1is formed as a first sun gear of the first planetary gear set32. The first sum shaft S1is formed as a first planetary carrier of the first planetary gear set32, wherein the first planetary carrier is also referred to as a first link. Furthermore, the second differential shaft D2is formed as a first internal gear of the first planetary gear set32. Furthermore, it is provided in the exemplary embodiment shown in the figures that the third differential shaft D3is formed as a second sun gear of the second planetary gear set34. The fourth differential shaft D4is formed as a second planetary carrier of the second planetary gear set34, wherein the second planetary carrier is also referred to as a second link. The second sum shaft S2is formed as a second internal gear of the second planetary gear set34.

In the exemplary embodiment shown in the figures, the first planetary carrier is formed as a simple planetary carrier with first planetary gears46. The respective, first planetary gear46is rotatably mounted on the first planetary carrier, wherein the respective first planetary gear46meshes, in particular simultaneously, with the first sun gear and with the first internal gear.

The second planetary carrier is formed as a double planetary carrier with second planetary gears48and third planetary gears50, wherein preferably the second planetary gears48and the third planetary gears50are rotatably mounted on the second planetary carrier, i.e., on the double planetary carrier. Therefore, it is conceivable that, for example, the second planetary gears48are engaged with the second sun gear, however they are not engaged with the second internal gear and also not with the third planetary gears50, wherein it is conceivable that the third planetary gears50are engaged with the second internal gear, however not with the second sun gear and not with the second planetary gears48. Thus, for example, the second sun gear meshes with the second planetary gears48, and the third planetary gears50mesh with the second internal gear, whereby, for example, the planetary gears48and50mesh with each other or the planetary gears48and50do not mesh with each other. Furthermore, the second planetary gears48do not mesh with second internal gear, and the third planetary gears50do not mesh with the second sun gear. Furthermore, the first planetary gears46are formed separately from the second planetary gears48and separately from the third planetary gears50.

In the exemplary embodiment shown in the figures, the fifth differential shaft D5is formed as a third sun gear of the third planetary gear set44. Furthermore, the third sum shaft S3is formed as a third planetary carrier of the third planetary gear set44, and the sixth differential shaft D6is formed as a third internal gear of the third planetary gear set44. In this case, preferably the third planetary carrier is formed as a simple planetary carrier with the fourth planetary gears52, which are rotatably mounted on the third planetary carrier. In this case, it is preferably provided that the respective third planetary gear52, in particular simultaneously, meshes with the third internal gear and with the third sun gear of the planetary gear set44, i.e., is engaged therewith.

The respective output shaft40or42is also referred to as an output drive shaft. In this case, the respective drive wheel12or14can be driven by the respective output drive shaft, i.e., by the output shaft40or42.

Preferably, the electric drive system10has a first transmission stage, not shown in the figures, which is arranged in the first torque flow and downstream of the first output shaft40in relation to a first torque flow along which the third torques can be discharged out of the planetary transmission30via the first output shaft40. A first side shaft (not shown in the figures) is arranged in the first torque flow for example, which side shaft is arranged in the first torque flow and in the process downstream of the first transmission stage. The first side shaft can be driven by the first output shaft40via the first transmission stage, wherein the drive wheel12can be driven by the first side shaft and thus by the first transmission stage via the first side shaft. The drive system10can further comprise a second transmission stage, not shown in the figures, which is arranged in the second torques flow and in the process downstream of the second output shaft42with respect to a second torques flow along which the fourth torques can be discharged from the planetary transmission30via the second output shaft42. In the second torques flow downstream of the second transmission stage, a second side shaft, not shown in the figures, is arranged, wherein the drive wheel14can be driven by the second transmission stage via the second side shaft. Furthermore, the second side shaft can be driven by the second output shaft42via the second transmission stage. As a result, the first side shaft can be driven by the output shaft40via the first transmission stage. The respective transmission stage is also referred to as the final drive (FD). Preferably, the first transmission stage is a fourth planetary gear set, wherein it is conceivable that the second transmission stage is a fifth planetary gear set. Preferably, the fourth planetary gear set and the fifth planetary gear set are of the same design, i.e., identical or the same in terms of their construction and thus in particular in terms of their transmission ratio.

It has also proved to be particularly advantageous if the transmission stages, the planetary gear sets32,34and44and the rotors20and28are arranged coaxially to each other. Furthermore, it is preferably provided that the transmission stages are arranged in the housing22. It is thus very preferably provided that the planetary gear sets32,34and44as well as the rotors20and28and also the transmission stages are arranged in the common housing22.

In the, or through the, first state, a pure differential operation can be achieved for example, whereby the switching element SE1is closed and the switching element SE2is open. The first electric machine16feeds the respective first torque via the third planetary gear set44and ultimately via the second sun gear and the second planetary carrier, in particular the planetary transmission30, whereby here, for example, the electric machine24rotates idly, so to speak. The first planetary gear set32is also uninvolved here, so to speak, since the first sun gear in particular rotates idly. Via the first output drive shaft, i.e., via the first output shaft40and thus via the first planetary carrier, the respective third torque, in particular as half of the first torque generated or provided by the electric machine16, is transmitted to one of the drive wheels12and14, in particular to the drive wheel12, and via the second output drive shaft, thus via the second output shaft42and thus via the first internal gear, the fourth torque, in particular as the other half of the first torque provided by the electric machine16and in particular introduced into the planetary transmission30, is transmitted to the other of the drive wheels12and14, in particular to the drive wheel14.

In, or through, the second state, shown inFIG.2, so-called active torque vectoring, i.e., an active torque distribution function, can be achieved, wherein the switching element SE1is open and the switching element SE2is closed. As a result, the third planetary gear set44is locked, as the third internal gear is connected to the third sun gear by means of the switching element SE2in a rotationally fixed manner. As a result, the electric machine16feeds its entire, respective first torque to the second sun gear or via the second sun gear, in particular into the planetary transmission30. The electric machine24feeds its respective second torque to the first sun gear or via the first sun gear, in particular into the planetary transmission30. It is therefore the case that the third planetary gear set44serves to ensure that, originating from a simple transmission and in particular the planetary transmission30, only two switching elements, namely the switching elements SE1and SE2, are required in order to be able to realize not only the second state, i.e., not only active torque vectoring, but also the first state and thus pure differential operation, wherein pure differential operation is also referred to as single-EM driving operation, during which or in which a half split, i.e., a50:50split, of the torque fed into the planetary transmission30, in particular the first torque, can be achieved or is achieved. In principle, the same effect could also be achieved without the third planetary gear set44, but four or five switching elements would then be required to achieve a high number of shaft switching operations in order to realize single-EM driving operation. This therefore means that the electric drive system10can save components and thus weight, costs, and installation space, while at the same time providing particularly advantageous drivability.

Although the invention has been illustrated and described in detail by way of preferred embodiments, the invention is not limited by the examples disclosed, and other variations can be derived from these by the person skilled in the art without leaving the scope of the invention. It is therefore clear that there is a plurality of possible variations. It is also clear that embodiments stated by way of example are only really examples that are not to be seen as limiting the scope, application possibilities or configuration of the invention in any way. In fact, the preceding description and the description of the figures enable the person skilled in the art to implement the exemplary embodiments in concrete manner, wherein, with the knowledge of the disclosed inventive concept, the person skilled in the art is able to undertake various changes, for example, with regard to the functioning or arrangement of individual elements stated in an exemplary embodiment without leaving the scope of the invention, which is defined by the claims and their legal equivalents, such as further explanations in the description.

REFERENCE SIGN LIST

10 Electric drive system12Drive wheel14Drive wheel16First electric machine18First stator20First rotor21Arrow22Housing24Second electric machine26Second stator28Second rotor29Arrow30Planetary transmission32First planetary gear set34Second planetary gear set36First input shaft38Second input shaft40First output shaft41Arrow42Second output shaft43Arrow44Third planetary gear set46First planetary gear48Second planetary gear50Third planetary gear52Fourth planetary gearD1First differential shaftD2Second differential shaftD3Third differential shaftD4Fourth differential shaftD5Fifth differential shaftD6Sixth differential shaftS1First sum shaftS2Second sum shaftS3Third sum shaftSE1First switching elementSE2Second switching element