Motor vehicle transmission for an at least partially electrically powered motor vehicle

Abstract

The invention relates to a motor vehicle transmission (3), comprising an input shaft (6), an output shaft (7), a first planetary gear set (P1) and a second planetary gear set (P2), wherein the input shaft (6) is provided for coupling to at least one drive motor. Furthermore, a first shifting element (A), a second shifting element (B), a third shifting element (C), and a fourth shifting element (D) are provided, at least functionally, to implement different power flow paths between the input shaft (6) and the output shaft (7) via the planetary gear sets (P1, P2).

Description

[0001] The invention relates to a motor vehicle transmission for an at least partially electrically driven motor vehicle, comprising a drive shaft, an output shaft and a first planetary gear set and a second planetary gear set, wherein the first planetary gear set and the second planetary gear set each have a first element, a second element and a third element in the form of a sun gear, a planet carrier and a ring gear, wherein the drive shaft is provided for coupling to at least one drive machine and the third element of the first planetary gear set is fixed, wherein the second element of the first planetary gear set and the third element of the second planetary gear set are connected to one another in a rotationally fixed manner, and wherein at least functionally a first shifting element, a second shifting element and a third shifting element are provided.Furthermore, the invention relates to a drive unit for an at least partially electrically driven motor vehicle, an electrically driven motor vehicle drive axle for an at least partially electrically driven motor vehicle and a hybrid or electric vehicle.

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

[0003] DE 10 2019 202 994 A1 discloses a motor vehicle drive axle for an electric vehicle, wherein the motor vehicle drive axle comprises a drive unit composed of an electric motor and a motor vehicle transmission. In addition to a drive shaft and an output shaft, the motor vehicle transmission comprises two planetary gear sets, each composed of elements in the form of a sun gear, a planet carrier, and a ring gear. Within the drive unit, a rotationally fixed connection to the upstream electric motor is established on the drive shaft, while the output shaft is connected to a differential gear set, which serves to distribute the power to output shafts of the motor vehicle drive axle. In addition, the motor vehicle transmission has a switching device which, in a variant of DE 10 2019 202 994 A1, maps the functions of three switching elements.A coupling element of the switching device can assume different switching states and thereby realize different power flow guidance from the drive shaft via the planetary gear sets to the output shaft.

[0004] Based on the prior art described above, it is the object of the present invention to realize a suitable alternative to a motor vehicle transmission.

[0005] This object is achieved based on the preamble of claim 1 in conjunction with its characterizing features. The dependent claims that follow therefrom each represent advantageous developments of the invention. A drive unit comprising a motor vehicle transmission according to the invention is further the subject of claims 12 to 14. Furthermore, claim 15 relates to an electrically driven motor vehicle drive axle for an at least partially electrically driven motor vehicle, while claim 16 relates to a hybrid or electric vehicle. Finally, claim 17 relates to a method for operating a motor vehicle transmission according to the invention.

[0006] According to the invention, a motor vehicle transmission comprises an input shaft, an output shaft, and a first planetary gear set and a second planetary gear set. The first planetary gear set and the second planetary gear set each have a first element, a second element, and a third element in the form of a sun gear, a planet carrier, and a ring gear. The input shaft is provided for coupling to at least one drive motor. In addition, the third element of the first planetary gear set is fixed. Furthermore, the second element of the first planetary gear set and the third element of the second planetary gear set are connected to one another in a rotationally fixed manner. At least functionally, a first shifting element, a second shifting element, and a third shifting element are also provided.

[0007] For the purposes of the invention, a “shaft,” such as the respective drive shaft or output shaft, is understood to be a rotatable component of the transmission via which a power flow can be guided between components. The respective shaft can connect the components axially or radially, or even both axially and radially. The respective shaft can also be in the form of an intermediate piece via which a respective component is connected, for example, purely radially. Furthermore, depending on its course and connection to the components or the ability to connect to them, the respective shaft can be designed as a solid shaft, a hollow shaft, or partly as a solid and partly as a hollow shaft. Alternatively or additionally, the respective shaft can be designed in one or more parts.

[0008] For the purposes of the invention, "axial" refers to an orientation in the direction of a longitudinal center axis of the motor vehicle transmission, parallel to which the rotational axes of the shafts of the motor vehicle transmission and the elements of the planetary gear sets are also oriented. "Radial" then refers to an orientation in the diameter direction of a respective component of the transmission, in particular a respective shaft or a respective element of the planetary gear sets.

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

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

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

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

[0013] The first planetary gear set and the second planetary gear set each consist of a first element, a second element, and a third element, with one of these elements each being configured as a sun gear, one element as a planet carrier, and one element as a ring gear. Preferably, the individual planetary gear set is a minus planetary gear set, in which the respective planet carrier rotatably supports at least one planetary gear, with the at least one planetary gear meshing with both the respective sun gear and the respective ring gear.In a design of the individual planetary gear set as a negative planetary gear set, the first element of each planetary gear set is the respective sun gear, the second element of each planetary gear set is the respective planet carrier, and the third element of each planetary gear set is the respective ring gear. In particular, several planetary gears are rotatably mounted in the respective planet carrier.

[0014] Alternatively, one or both planetary gear sets could also be designed as a plus planetary gear set. In this case, at least one pair of planetary gears is rotatably mounted in the respective planet carrier, with one planetary gear meshing with the respective sun gear and one planetary gear meshing with the respective ring gear. In addition, the planetary gears of the at least one pair of planetary gears mesh with one another. In contrast to a design as a minus planetary gear set, the first element of the respective planetary gear set is preferably the respective sun gear, the second element of the respective planetary gear set is the respective ring gear, and the third element of the respective planetary gear set is the respective planet carrier. In comparison to a design as a minus planetary gear set, the stationary gear ratio of the respective planetary gear set must also be increased by one.As already described above, the first planetary gear set and the second planetary gear set are preferably each a minus planetary gear set.

[0015] In the motor vehicle transmission according to the invention, the drive shaft and the output shaft are arranged, in particular, coaxially to one another, with the first planetary gear set and the second planetary gear set also preferably being positioned coaxially to the drive shaft and the output shaft. This allows for a particularly compact design of the motor vehicle transmission in the radial direction.

[0016] The invention now includes the technical teaching that the input shaft is connected in a rotationally fixed manner to the first element of the second planetary gear set. In the actuated state of the at least functionally provided first shifting element, the first element of the first planetary gear set is connected in a rotationally fixed manner to the input shaft, whereas in the actuated state of the at least functionally provided second shifting element, the output shaft is connected in a rotationally fixed manner to the second element of the second planetary gear set. Furthermore, in the actuated state of the at least functionally provided third shifting element, the output shaft is connected in a rotationally fixed manner to the second element of the first planetary gear set and the third element of the second planetary gear set.In addition, at least functionally, a fourth switching element is also provided, in the actuated state of which the first element of the first planetary gear set is connected in a rotationally fixed manner to the second element of the second planetary gear set.

[0017] In the motor vehicle transmission according to the invention, the first element of the second planetary gear set and the input shaft are permanently connected to one another in a rotationally fixed manner, so that the first element of the second planetary gear set and the input shaft always rotate together. Furthermore, the second element of the first planetary gear set and the third element of the second planetary gear set are permanently connected to one another in a rotationally fixed manner, whereby the second element of the first planetary gear set and the third element of the second planetary gear set constantly rotate together. Furthermore, the third element of the first planetary gear set is permanently fixed and thus constantly prevented from rotating.

[0018] For the purposes of the invention, a permanent "rotatable" connection of transmission components means that these components, which are constantly connected or in contact with one another in a rotationally fixed manner, are rigidly connected to one another and thus always have the same rotational speed. The components, which are connected or in contact with one another in a rotationally fixed manner, can be separate components that are fastened to one another, for example, via an intermediate shaft. Alternatively, components which are connected or in contact with one another in a rotationally fixed manner can also be designed as a single piece and thus form a single component. This is particularly true when these components are arranged spatially close to one another.

[0019] The motor vehicle transmission according to the invention has, at least functionally, a first shifting element, a second shifting element, a third shifting element, and a fourth shifting element for representing different couplings of the drive shaft to the output shaft and thus for switching different gear ratios between the drive shaft and the output shaft. Particularly preferably, at least functionally, four shifting elements in the form of the first shifting element, the second shifting element, the third shifting element, and the fourth shifting element are provided to represent the different gear ratios between the drive shaft and the output shaft. The fact that a respective shifting element is provided "at least functionally" means, within the meaning of the invention, that at least the respective function of the respective shifting element is represented in the motor vehicle transmission according to the invention.The respective switching element can actually be physically present as a single switching element, or the function of the respective switching element can be represented by another component, such as a switching device. A component representing the function can then combine the functions of two or more switching elements into one device.

[0020] The representation of an actuated state of the first shifting element results in the first element of the first planetary gear set and the input shaft being connected to one another in a rotationally fixed manner, whereby, in the actuated state of the at least functionally provided first shifting element, the first element of the first planetary gear set rotates together with the input shaft and thus also with the first element of the second planetary gear set. If, however, the actuated state of the second shifting element is realized, the output shaft and the second element of the second planetary gear set are connected to one another in a rotationally fixed manner and thus rotate together in the actuated state of the second shifting element.

[0021] By implementing the actuated state of the third shifting element, the output shaft and the second element of the first planetary gear set, as well as the third element of the second planetary gear set, are connected to one another in a rotationally fixed manner, whereupon the output shaft, the second element of the first planetary gear set, and the third element of the second planetary gear set rotate together in the actuated state of the third shifting element. Furthermore, the first element of the first planetary gear set can be connected to the second element of the second planetary gear set in a rotationally fixed manner by representing the actuated state of the fourth shifting element.

[0022] Within the scope of the invention, securing a component of the motor vehicle transmission via an at least functionally provided shifting element or a rotationally fixed connection between components of the motor vehicle transmission via an at least functionally provided shifting element means that the component in question is not permanently secured or the components are not permanently coupled to one another, but rather securing or a rotationally fixed connection is only achieved by displaying an actuated state of the at least functionally provided, intermediate shifting element. In this case, an actuated state of the at least functionally provided shifting element within the meaning of the invention means that a closed state of the shifting element in question is displayed and, as a result, the components directly connected to it are aligned with one another in terms of their rotational movements.If at least the function of a positive-locking switching element is depicted, the components directly connected to one another in a rotationally fixed manner will run at the same speed. Whereas, if at least the function of a non-positive switching element is depicted, speed differences between the components may exist even after the actuated state of the switching element is depicted. This intended or unintended state is nevertheless referred to within the scope of the invention as a rotationally fixed connection of the respective components via the at least functionally provided switching element.

[0023] A locked state of a component of the motor vehicle transmission is realized, within the meaning of the invention, in particular by a rotationally fixed connection to a permanently fixed component, which can be a housing of the motor vehicle transmission, a part of the housing, or a component permanently connected thereto in a rotationally fixed manner. The third element of the first planetary gear set is permanently connected to this permanently locked component in a rotationally fixed manner, whereby a one-piece design of the third element of the first planetary gear set with the permanently locked component could also be realized.

[0024] The inventive design of a motor vehicle transmission has the advantage of allowing the realization of a compact motor vehicle transmission. Furthermore, the motor vehicle transmission allows for gear ratios to be switched between the input shaft and the output shaft, which are suitable for the integration of a drive motor, particularly one configured as an electric motor.

[0025] Thus, a first gear can be shifted between the drive shaft and the output shaft by simultaneously actuating the third shifting element and the fourth shifting element. A second gear is created between the drive shaft and the output shaft by simultaneously actuating the first shifting element and the third shifting element. Furthermore, a third gear can be shifted between the drive shaft and the output shaft by simultaneously actuating the first shifting element and the second shifting element. This makes it possible to implement a suitable shifting sequence, wherein when the gears are shifted consecutively, only the shifting state of two of the at least functionally provided shifting elements needs to be changed.

[0026] According to one embodiment, the first shifting element and the fourth shifting element are formed by a common shifting device which has a coupling element. This coupling element can be transferred into a first shifting state and a second shifting state, wherein the coupling element in the first shifting state functionally replicates the actuated state of the first shifting element and connects the first element of the first planetary gear set in a rotationally fixed manner to the drive shaft. In its second shifting state, however, the coupling element functionally replicates the actuated state of the fourth shifting element and connects the first element of the first planetary gear set in a rotationally fixed manner to the second element of the second planetary gear set. In this case, the function of the first shifting element and the fourth shifting element is therefore reproduced by a common shifting device, which enables a particularly compact arrangement.In addition, a control actuator can be provided for actuating the switching elements, via which the coupling element can be transferred into its various switching states. Preferably, in addition to the two switching states, the coupling element can also be moved into a neutral state, in which neither an actuated state of the first switching element nor an actuated state of the fourth switching element is represented by the switching device.

[0027] In a further development of the aforementioned embodiment, the coupling element is guided in a rotationally fixed and axially displaceable manner on a first toothing in both switching states and during axial displacement between the two switching states. This first toothing is rotationally fixedly connected to the first element of the first planetary gear set. In its first switching state, the coupling element then additionally engages with a second toothing when the toothing is engaged with the first toothing, which is rotationally fixedly connected to the drive shaft. Furthermore, in the second switching state, the coupling element additionally engages with a third toothing when the toothing is engaged with the first toothing, which is rotationally fixedly connected to the second element of the second planetary gear set.The coupling element of the shifting device is particularly preferably designed as a sliding sleeve, with the toothings more preferably being designed as claw toothings, so that the shifting device replicates the function of unsynchronized claw shifting elements. Within the scope of the invention, however, the first shifting element and the fourth shifting element could also be designed as individual shifting elements, with the first shifting element and the fourth shifting element each being able to be a positive-locking shifting element, such as a claw shifting element or a locking synchronizer, or a non-positive-locking shifting element, such as a multi-disk shifting element.

[0028] Alternatively, but preferably in addition to the aforementioned embodiment and its further development, the second shifting element and the third shifting element are formed by a common shifting device which has a coupling element. The coupling element of this shifting device can be transferred into a first shifting state and into a second shifting state, wherein the coupling element in the first shifting state functionally represents the actuated state of the second shifting element and connects the output shaft in a rotationally fixed manner to the second element of the second planetary gear set. In its second shifting state, the coupling element functionally represents the actuated state of the third shifting element and connects the output shaft in a rotationally fixed manner to the second element of the first planetary gear set and the third element of the second planetary gear set.Advantageously, the function of the second switching element and the third switching element is thereby mapped by the switching device, which, in addition to a compact arrangement, also requires only one actuating actuator. In particular, in addition to the two switching states, the coupling element can then also be moved into a neutral state, in which neither an actuated state of the second switching element nor an actuated state of the third switching element is represented by the switching device.

[0029] Preferably, in both switching states and during axial displacement between the two switching states, the coupling element is guided in a rotationally fixed and axially displaceable manner on a first toothing which is rotationally fixedly connected to the output shaft. If the coupling element is transferred to its first switching state, the coupling element, while meshing with the first toothing, additionally engages with a second toothing which is rotationally fixedly connected to the second element of the second planetary gear set. In the second switching state, the coupling element, while meshing with the first toothing, additionally engages with a third toothing which is rotationally fixedly connected to the first element of the second planetary gear set and the third element of the second planetary gear set.Most preferably, the coupling element of the shifting device is designed as a sliding sleeve, with the toothings being designed, in particular, as claw toothings, so that the shifting device replicates the function of unsynchronized claw shifting elements. Alternatively, the second shifting element and the third shifting element can also be designed as individual shifting elements. The second shifting element and the third shifting element can each be designed as a positive-locking shifting element, such as a claw shifting element or a locking synchronizer, or as a non-positive-locking shifting element, such as a multi-disk shifting element.

[0030] Particularly preferably, the two switching devices described above are implemented together in the motor vehicle transmission according to the invention, so that the functions of the first switching element, the second switching element, the third switching element and the fourth switching element can be represented by two switching devices via the associated coupling elements. This makes it possible to achieve a particularly compact design of the motor vehicle transmission. Within the scope of the invention, a discrete axial position of the respective coupling element can be assigned to the respective "switching state" or the respective "neutral state" of the respective coupling element, wherein the respective "switching state" or the respective "neutral state" is preferably defined by an axial adjustment range within which the coupling element is to be positioned in order to implement the respective switching state or the respective neutral state.

[0031] According to one embodiment of the invention, the planetary gear sets are arranged axially in a sequence of first planetary gear set and second planetary gear set at a connection point of the drive shaft, at which the coupling of the drive shaft to the at least one drive motor is to be established. This allows a suitable design of the motor vehicle transmission according to the invention to be achieved.

[0032] In a further development of the aforementioned embodiment, the at least functionally provided first shifting element and / or the at least functionally provided fourth shifting element are arranged axially between the first planetary gear set and the second planetary gear set. If the functions of the first shifting element and the fourth shifting element are represented by a common shifting device, this shifting device is then preferably positioned axially between the planetary gear sets.

[0033] Alternatively, but preferably additionally, the at least functionally provided second shifting element and / or the at least functionally provided third shifting element are each arranged axially on a side of the second planetary gear set facing away from the first planetary gear set. If a shifting device is provided that replicates the functions of the second shifting element and the third shifting element, this shifting device is then arranged axially on the side of the second planetary gear set facing away from the first planetary gear set.

[0034] In one embodiment of the invention, the output shaft is coupled to an input element of a differential gear set, which couples the output shaft to two output shafts. As a result, the output shaft is drivingly coupled to the two output shafts via the differential gear set. This advantageously makes it possible to distribute a drive torque generated at the output shaft between the two output shafts, with the differential gear set also being able to equalize the speed between the output shafts. The differential gear set functions in particular as a transverse differential and is preferably designed in the manner of a bevel gear differential. The transverse differential thus formed is preferably used to distribute a drive movement transmitted to the output shaft of the motor vehicle transmission to the output shafts, which are preferably assigned to a motor vehicle drive axle.However, the differential gear set can also function as a longitudinal differential, which can be used to distribute drive power across multiple drive axles. As an alternative to a bevel gear differential, the differential gear set can also be designed as a planetary gear differential, a spur gear differential, etc., within the scope of the invention.

[0035] The input element to which the output shaft is coupled is preferably a differential cage of the differential gear set. When the differential gear set is used as a transverse differential and the motor vehicle transmission is installed transversely to a direction of travel of the associated motor vehicle, the output shaft is then preferably connected to the input element in a rotationally fixed manner. This is also achieved in particular when the differential gear set functions as a longitudinal differential and the motor vehicle transmission is aligned in the direction of travel of the motor vehicle. When the motor vehicle transmission is installed in the direction of travel and the differential gear set is used as a transverse differential, the output shaft is coupled to the input element via a bevel drive.Such a bevel drive is also preferably used when the differential gear set is a longitudinal differential and the motor vehicle transmission is aligned transversely to the direction of travel.

[0036] In a further development of the aforementioned embodiment, the differential gearset axially overlaps the second planetary gearset and is positioned radially inward of the two planetary gearsets. Within the scope of the invention, however, the differential gearset could also be provided axially between the first planetary gearset and the second planetary gearset, with the differential gearset then being positioned radially inward of the planetary gearsets. This enables advantageous positioning of the differential gearset near the center between the drive wheels of the axle, particularly when the motor vehicle transmission according to the invention is used in a motor vehicle drive axle.Further alternatively, the differential gear set can also be arranged axially on a side of the first planetary gear set facing away from the second planetary gear set or axially on a side of the second planetary gear set facing away from the first planetary gear set, wherein the differential gear set is preferably always provided radially inward of the two planetary gear sets.

[0037] Alternatively or in addition to the aforementioned development, the output shafts are each coupled to the differential gear set via an intermediate gear ratio. The additional gear ratios thus provided can advantageously be used to change the overall gear ratio achievable via the motor vehicle transmission. The gear ratios can preferably each be configured as planetary gear sets.

[0038] The invention also relates to a drive unit that, in addition to an electric motor, has a motor vehicle transmission according to one or more of the variants described above. A rotor of the electric motor is coupled to the drive shaft of the motor vehicle transmission. Within the scope of the invention, the electric motor can be operated, in particular, as a generator on the one hand and as an electric motor on the other. This makes it possible to create a drive unit that is suitable for use in a motor vehicle in the form of an electric or hybrid vehicle.

[0039] In this drive unit according to the invention, the first planetary gear set or the second planetary gear set, or both the first planetary gear set and the second planetary gear set, can be arranged so as to at least axially overlap and radially inward of the electric motor. This allows a compact design of the drive unit to be achieved. "Axially at least overlapping" means that at least a portion of the first planetary gear set and / or the second planetary gear set lies axially in the same plane as at least a portion of the electric motor.

[0040] The rotor of the electric machine can be connected in a rotationally fixed manner to the drive shaft of the motor vehicle transmission, with the electric machine then being arranged coaxially with the drive shaft. As a result, the drive shaft and the rotor of the electric machine run at the same speed during operation. Alternatively, it is also conceivable for the rotor of the electric machine to be connected in a rotationally fixed manner to an intermediate shaft of the motor vehicle transmission, which is coupled to the drive shaft via at least one gear ratio, so that the electric machine may then be axially offset from the drive shaft. Depending on the design of the at least one gear ratio, a coaxial arrangement of the electric machine with the drive shaft is also possible.

[0041] A drive unit designed according to one of the aforementioned variants is, in particular, part of an electrically driven motor vehicle drive axle, which is intended for use in an electric or hybrid vehicle. The motor vehicle transmission preferably has a differential gear set coupled to the output shaft, thereby coupling the output shaft to output shafts. Each of the output shafts is assigned to a drive wheel of the motor vehicle drive axle.

[0042] Within the scope of the invention, the aforementioned motor vehicle drive axle is provided for a hybrid or electric vehicle, which may be a passenger car or a commercial vehicle. A commercial vehicle may be an at least partially electrically powered van or a light to medium-duty bus or truck.

[0043] An advantageous embodiment of the invention, which is explained below, is illustrated in the drawings. They show: Fig. 1 is a schematic view of a drive unit according to an embodiment of the invention; Fig. 2 an exemplary circuit diagram of a motor vehicle transmission of the drive unit from Fig. 1; and Fig. 3 is a schematic view of an electric vehicle according to a preferred embodiment of the invention.

[0044] Out of Fig. Figure 1 shows a schematic view of a drive unit 1 designed according to one embodiment of the invention. This drive unit 1 consists of an electric machine 2 and a motor vehicle transmission 3, which is designed according to one possible embodiment of the invention. The electric machine 2 is formed in a manner known in principle to those skilled in the art by a stator 4 and a rotor 5, whereby the electric machine 2 can be operated both as a generator and as an electric motor.

[0045] In addition to an input shaft 6 and an output shaft 7, the motor vehicle transmission 3 has two planetary gear sets P1 and P2, each composed of a first element E11 or E12, a second element E21 or E22, and a third element E31 or E32. The respective first element E11 or E12 of the respective planetary gear set P1 or P2 is a respective sun gear, while the respective second element E21 or E22 of the respective planetary gear set P1 or P2 is designed as a respective planet carrier. Furthermore, the respective third element E31 or E32 of the respective planetary gear set P1 or P2 is a respective ring gear of the respective planetary gear set P1 or P2.

[0046] In each case, at least one planetary gear is rotatably mounted in the respective planet carrier of the respective planetary gear set P1 or P2, which planetary gear meshes with both the respective sun gear and the respective ring gear of the respective planetary gear set P1 or P2. In this respect, the planetary gear sets P1 and P2 are designed as minus planetary sets. Within the scope of the invention, however, a design of one or both planetary gear sets P1 and P2 as a plus planetary set is also conceivable, for which purpose, in comparison to the respective design as a minus planetary set, the respective second element E21 or E22 is to be formed by the respective ring gear and the respective third element E31 or E32 is to be formed by the respective planet carrier. Furthermore, a stationary gear ratio is to be increased by one when the respective planetary gear set is designed as a plus planetary set compared to a design as a minus planetary set.In a plus planetary gear set, at least one pair of planetary gears is rotatably mounted in the respective planetary carrier, with one planetary gear meshing with the respective sun gear and one planetary gear meshing with the respective ring gear. Furthermore, the planetary gears of at least one pair of planetary gears mesh with each other.

[0047] In this case, the first element E12 of the second planetary gear set P2 is rotationally fixedly connected to the drive shaft 6, which is also rotationally fixedly connected to the rotor 5 of the electric machine 2 at a connection point 8. In this respect, the first element E12 of the second planetary gear set P2 and the rotor 5 are also rotationally fixedly connected to one another via the drive shaft 6, whereby the first element E12 and the rotor 5 always rotate at the same speed. Within the scope of the invention, the drive shaft 6 can be designed as a single piece with the rotor 5 of the electric machine 2 and / or with the first element E12 of the second planetary gear set P2.

[0048] The second element E21 of the first planetary gear set P1 is permanently connected in a rotationally fixed manner to the third element E32 of the second planetary gear set P2. This rotationally fixed connection is established via a shaft 9, which for this purpose is, on the one hand, connected in a rotationally fixed manner to the second element E21 of the first planetary gear set P1 and, on the other hand, connected in a rotationally fixed manner to the third element E32 of the second planetary gear set P2. The shaft 9 could be formed integrally with the second element E21 of the first planetary gear set P1 and / or integrally with the third element E32 of the second planetary gear set P2.

[0049] Furthermore, the first element E11 of the first planetary gear set P1 is non-rotatably connected to a shaft 10, which in this case is present as a radial shaft piece and is preferably designed as a single piece with the first element E11 of the first planetary gear set P1. The second element E22 of the second planetary gear set P2 is non-rotatably connected to a shaft 11, whereby a single-piece design of the shaft 11 and the second element E22 of the second planetary gear set P2 would also be conceivable here. Furthermore, the third element E31 of the first planetary gear set P1 is non-rotatably connected to a permanently fixed component 12, which is preferably a transmission housing of the motor vehicle transmission 3, a part of such a transmission housing, or a component non-rotatably connected thereto. As a result, the third element E31 of the first planetary gear set P1 is constantly prevented from rotating.

[0050] The output shaft 7 is connected in a rotationally fixed manner to an input element 13 of a differential gear set 14, which is designed in particular as a bevel gear differential and, in a manner known in principle to those skilled in the art, divides a drive torque introduced into the input element 13 via the output shaft 7 between two output shafts 15 and 16. The two output shafts 15 and 16 are each coupled to the differential gear set 13 via an intermediate gear stage 17 and 18, respectively. The differential gear set 14 enables speed differences between the output shafts 15 and 16 in a manner known in principle to those skilled in the art. The gear stages 17 and 18 - shown only schematically here - are preferably designed as planetary gear sets.

[0051] The motor vehicle transmission 3 also has two shifting devices 19 and 20. The shifting device 19 includes a coupling element 21 in the form of a sliding sleeve, which is guided in a rotationally fixed and axially displaceable manner on a toothing 22. The toothing 22 is formed on the shaft 10 and is thus rotationally fixedly connected to the first element E11 of the first planetary gear set P1. Axial displacements of the coupling element 21 on the toothing 22 can be performed via an actuating actuator—not shown here—which is preferably designed as an electromechanical actuating actuator.

[0052] The coupling element 21 can be moved axially between two different switching states via the actuating actuator under constant guidance on the toothing 22, wherein in each of the switching states, the coupling element 21 engages with a respective associated toothing 23 or 24. The toothing 23 is connected in a rotationally fixed manner to the drive shaft 6 and thus also to the first element E12 of the second planetary gear set P2, while the toothing 24 is connected in a rotationally fixed manner to the second element E22 of the second planetary gear set P2 and is provided for this purpose on the shaft 11.

[0053] The switching device 19 maps the function of two switching elements A and D, whose respective actuated state is represented by the switching device 19 in each of the switching states of the coupling element 21. Thus, an actuated state of the switching element A is realized in a first switching state of the coupling element 21, in which the coupling element 21, while meshing with the toothing 22, additionally engages the toothing 23. This results in a rotationally fixed connection of the shaft 10 to the drive shaft 6 and thus also of the first element E11 of the first planetary gear set P1 to the first element E12 of the second planetary gear set P2.

[0054] From the first switching state, the coupling element 21 can be transferred via the actuator into a neutral state, which Fig. 1 and in which the coupling element 21 meshes only with the toothing 22. As a result, in this neutral state, no coupling of the first element E11 of the first planetary gear set P1 is established via the coupling element 21.

[0055] In addition to transferring the coupling element 21 to the first switching state, the coupling element 21 can also be moved from the neutral state into a second switching state, in which the coupling element 21, while already meshing with the toothing 22, also meshes with the toothing 24. The coupling element 21 thereby connects the shafts 10 and 11 in a rotationally fixed manner, resulting in a rotationally fixed connection between the first element E11 of the first planetary gear set P1 and the second element E22 of the second planetary gear set P2. In the second switching state of the coupling element 21, an actuated state of the switching element D is represented.

[0056] The switching device 20 also has a coupling element 25 in the form of a sliding sleeve, wherein the coupling element 25 is guided in a rotationally fixed and axially displaceable manner on a toothing 26 which is formed on the output shaft 7. From a Fig. 1, in which the coupling element 25 does not couple the output shaft 7, the coupling element 25 can be transferred axially into a first switching state via an associated actuating actuator (not shown here). In this first switching state, the coupling element 25, while meshing with the toothing 26, engages with a toothing 27 which is formed on the shaft 11 and is thus connected in a rotationally fixed manner to the second element E22 of the second planetary gear set P2. As a result, in the first switching state of the coupling element 25, there is a rotationally fixed connection between the output shaft 7 and the shaft 11 and thus also to the second element E22 of the second planetary gear set P2. In the first switching state of the coupling element 25, an actuated state of a switching element B is represented.

[0057] On the other hand, the coupling element 25 can also be transferred axially from the neutral state via the associated actuating actuator into a second switching state, in which the coupling element 25, while still meshing with the toothing 26, additionally engages with a toothing 28. This toothing 28 is formed on the shaft 9 and is thus connected in a rotationally fixed manner to the second element E21 of the first planetary gear set P1 and to the third element E32 of the second planetary gear set P2. As a result, in the second switching state of the coupling element 25, a rotationally fixed connection between the shaft 9 and thus also the second element E21 of the first planetary gear set P1 and the third element E32 of the second planetary gear set P2 is established with the output shaft 7, whereby the second element E21 of the first planetary gear set P1 and the third element E32 of the second planetary gear set P2 rotate together with the output shaft 7 in the second switching state of the coupling element 25.This represents an actuated state of a switching element C. In this respect, the switching device 20 implements the functions of the two switching elements B and C.

[0058] In the present case, the electric machine 2 is positioned coaxially to the motor vehicle transmission 3, in which the input shaft 6, the planetary gear sets P1 and P2, the output shaft 7, the shafts 9, 10 and 11, the output shafts 15 and 16 and also the differential gear set 14 are arranged coaxially to one another. After the input shaft 6 is connected to the rotor 5 of the electric machine 2 at its connection point 8, the two planetary gear sets P1 and P2 then follow axially in the order of first planetary gear set P1 and second planetary gear set P2. The switching device 19 forming the switching elements A and D is positioned axially partially overlapping the first planetary gear set P1 and partially axially between the first planetary gear set P1 and the second planetary gear set P2, with the switching device 19 being arranged radially inward of the first planetary gear set P1.Furthermore, the shifting device 20, which represents the two shifting elements B and C, is arranged axially on a side of the second planetary gear set P2 facing away from the first planetary gear set P1. The shifting device 20 is positioned radially substantially at the level of the first element E12 of the second planetary gear set P2.

[0059] The differential gear set 14 is also positioned axially overlapping the second planetary gear set P2 and is arranged radially inward of the two planetary gear sets P1 and P2. While the output shafts 15 and 16 are each designed at least substantially as solid shafts, the input shaft 6, the output shaft 7, and the shafts 9, 10, and 11 are each designed as hollow shafts.

[0060] Out of Fig. 2 shows an exemplary shift diagram of the motor vehicle transmission 3 Fig. 1. As can be seen from the exemplary shift diagram, in the motor vehicle transmission 3, a total of three different gear ratios in the form of gears G1, G2, and G3 can be switched between the input shaft 6 and the output shaft 7. In the columns of the shift diagram, an X indicates which of the shift elements A, B, C, and D formed by the shift devices 19 and 20 represents an actuated state in the individual gear.

[0061] As in Fig. 2, a first gear G1 is engaged between the drive shaft 6 and the output shaft 7 by the switching device 19 displaying the actuated state of the switching element D and, at the same time, the switching device 20 displaying the actuated state of the switching element C. To engage a second gear G2, the switching device 20 still has to display the actuated state of the switching element C and, at the same time, the switching device 19 displays the actuated state of the switching element A. Finally, a third gear G3 is produced between the drive shaft 6 and the output shaft 7 by the switching device 19 displaying the actuated state of the switching element A and, at the same time, the switching device 20 displays the actuated state of the switching element B.

[0062] Finally, Fig.3 shows a schematic view of an electric vehicle 29, which may in particular be an electric commercial vehicle, such as a van. In addition to a steerable, non-driven vehicle axle 30, the electric vehicle 29 also has a motor vehicle drive axle 31 with drive wheels 32 and 33. Part of the motor vehicle drive axle 31 is also the drive unit 1. The drive wheel 32 is connected to the output shaft 15 of the drive unit 1, while the drive wheel 33 is connected to the output shaft 16 of the drive unit 1.

[0063] While the vehicle axle 30 is a front axle of the electric vehicle 29, the motor vehicle drive axle 31 is a rear axle of the electric vehicle 29. However, alternatively or in addition to the motor vehicle drive axle 31, the vehicle axle 30 could also be designed as a driven axle with, if appropriate, an analogous structure of a drive unit.

[0064] By means of the embodiments according to the invention, a compact motor vehicle transmission can be realized which is suitable for the integration of an electric machine. Reference symbol 1 drive unit 2 electric machine 3 Motor vehicle transmissions 4 Stator 5 Rotor 6 Drive shaft 7 Output shaft 8 Junction 9 Wave 10 Wave 11 Wave 12 fixed component 13 Input element 14 Differential gear set 15 Output shaft 16 Output shaft 17 gear ratios 18 gear ratios 19 Switching device 20 Switching device 21 Coupling element 22 Gearing 23 Gearing 24 Gearing 25 coupling element 26 Gearing 27 Gearing 28 Gearing 29 electric vehicles 30 vehicle axle 31 Motor vehicle drive axle 32 drive wheel 33 Drive wheel P1 First planetary gear set P2 Second planetary gear set E11 First element of the first planetary gear set E21 Second element of the first planetary gear set E31 Third element first planetary gear set E12 First element of the second planetary gear set E22 Second element of second planetary gear set E32 Third element second planetary gear set A switching element B switching element C switching element D switching element G1 Gang G2 Gear G3 Gear QUOTES CONTAINED IN THE DESCRIPTION

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

[0000] DE 10 2019 202 994 A1

[0003]

Claims

[1] Motor vehicle transmission (3) for an at least partially electrically driven motor vehicle, comprising a drive shaft (6), an output shaft (7) and a first planetary gear set (P1) and a second planetary gear set (P2), wherein the first planetary gear set (P1) and the second planetary gear set (P2) each have a first element (E11, E12), a second element (E21, E22) and a third element (E31, E32) in the form of a sun gear, a planet carrier and a ring gear, wherein the drive shaft (6) is provided for coupling to at least one drive machine and the third element (E31) of the first planetary gear set (P1) is fixed, wherein the second element (E21) of the first planetary gear set (P1) and the third element (E32) of the second planetary gear set (P2) are connected to one another in a rotationally fixed manner, and wherein at least functionally a first shifting element (A), a second shifting element (B) and a third switching element (C) are provided,, characterized by , - that the drive shaft (6) is connected in a rotationally fixed manner to the first element (E12) of the second planetary gear set (P2), - that in the actuated state of the at least functionally provided first switching element (A), the first element (E11) of the first planetary gear set (P1) is connected in a rotationally fixed manner to the drive shaft (6), - that in the actuated state of the at least functionally provided second switching element (B), the output shaft (7) is connected in a rotationally fixed manner to the second element (E22) of the second planetary gear set (P2), - that in the actuated state of the at least functionally provided third switching element (C), the output shaft (7) is connected in a rotationally fixed manner to the second element (E21) of the first planetary gear set (P1) and the third element (E32) of the second planetary gear set (P2), - and that in addition, at least functionally, a fourth switching element (D) is provided, in the actuated state of which the first element (E11) of the first planetary gear set (P1) is connected in a rotationally fixed manner to the second element (E22) of the second planetary gear set (P2). [2] Motor vehicle transmission (3) according to claim 1, characterized byin that the first shifting element (A) and the fourth shifting element (D) are formed by a common shifting device (19) which has a coupling element (21), wherein the coupling element (21) can be transferred into a first shifting state and into a second shifting state, wherein the coupling element (21) in the first shifting state functionally maps the actuated state of the first shifting element (A) and connects the first element (E11) of the first planetary gear set (P1) in a rotationally fixed manner to the drive shaft (6), and wherein the coupling element (21) in the second shifting state functionally maps an actuated state of the fourth shifting element (D) and connects the first element (E11) of the first planetary gear set (P1) in a rotationally fixed manner to the second element (E22) of the second planetary gear set (P2). [3] Motor vehicle transmission (3) according to claim 2, characterized byin that the coupling element (21) is guided in a rotationally fixed and axially displaceable manner on a first toothing (22) in the two switching states and during an axial displacement between the two switching states, which first toothing is connected in a rotationally fixed manner to the first element (E11) of the first planetary gear set (P1), wherein the coupling element (21) in the first switching state, when there is tooth engagement with the first toothing (22), additionally engages in a second toothing (23) which is connected in a rotationally fixed manner to the drive shaft (6), and wherein the coupling element (21) in the second switching state, when there is tooth engagement with the first toothing (22), additionally engages in a third toothing (24) which is connected in a rotationally fixed manner to the second element (E22) of the second planetary gear set (P2). [4] Motor vehicle transmission (3) according to one of claims 1 to 3, characterized by, the second switching element (B) and the third switching element (C) are formed by a common switching device (20) which has a coupling element (25), wherein the coupling element (25) can be transferred into a first switching state and into a second switching state, wherein the coupling element (25) in the first switching state functionally maps the actuated state of the second switching element (B) and connects the output shaft (7) in a rotationally fixed manner to the second element (E22) of the second planetary gear set (P2), and wherein the coupling element (25) in the second switching state functionally maps the actuated state of the third switching element (C) and connects the output shaft (7) in a rotationally fixed manner to the second element (E21) of the first planetary gear set (P1) and the third element (E32) of the second planetary gear set (P2). [5] Motor vehicle transmission (3) according to claim 4, characterized byin that the coupling element (25) is guided in both switching states and during an axial displacement between the two switching states in a rotationally fixed and axially displaceable manner on a first toothing (26) which is connected in a rotationally fixed manner to the output shaft (7), wherein the coupling element (25) in the first switching state, when there is tooth engagement with the first toothing (26), additionally engages in a second toothing (27) which is connected in a rotationally fixed manner to the second element (E22) of the second planetary gear set (P2), and wherein the coupling element (25) in the second switching state, when there is tooth engagement with the first toothing (26), additionally engages in a third toothing (28) which is connected in a rotationally fixed manner to the second element (E21) of the first planetary gear set (P1) and the third element (E32) of the second planetary gear set (P2). [6] Motor vehicle transmission (3) according to one of the preceding claims, characterized bythat the planetary gear sets (P1, P2) are arranged axially in a sequence of first planetary gear set (P1) and second planetary gear set (P2) on a connection point (8) at which the coupling of the drive shaft (6) to the at least one drive machine is to be established. [7] Motor vehicle transmission (3) according to claim 6, characterized by that the at least functionally provided first shifting element (A) and / or the at least functionally provided fourth shifting element (D) are arranged axially between the first planetary gear set (P1) and the second planetary gear set (P2). [8] Motor vehicle transmission (3) according to claim 6 or 7, characterized by that the at least functionally provided second shifting element (B) and / or the at least functionally provided third shifting element (C) are each arranged axially on a side of the second planetary gear set (P2) facing away from the first planetary gear set (P1). [9] Motor vehicle transmission (3) according to one of the preceding claims, characterized by that the output shaft (7) is coupled to an input element (13) of a differential gear set (14) which couples the output shaft (7) to two output shafts (15, 16). [10] Motor vehicle transmission (3) according to claim 9, characterized by that the differential gear set (14) is arranged axially overlapping with the second planetary gear set (P2) and is placed radially inward of the planetary gear sets (P1, P2). [11] Motor vehicle transmission (3) according to claim 9 or 10, characterized by that the output shafts (15, 16) are each coupled to the differential gear set (14) via an intermediate gear ratio stage (17, 18). [12] Drive unit (1) for an at least partially electrically driven motor vehicle, comprising an electric machine (2) and a motor vehicle transmission (3) according to one or more of claims 1 to 11, wherein a rotor (5) of the electric machine (2) is coupled to the drive shaft (6) of the motor vehicle transmission (3). [13] Drive unit according to claim 12, characterized by that the first planetary gear set and / or the second planetary gear set is arranged axially overlapping with and radially inward of the electric machine. [14] Drive unit (1) according to claim 12 or 13, characterized by that the rotor (5) is arranged coaxially to the drive shaft (6) and is connected to the drive shaft (6) in a rotationally fixed manner. [15] Electrically driven motor vehicle drive axle (31) for an at least partially electrically driven motor vehicle, comprising a drive unit (1) according to one of claims 12 to 14. [16] Hybrid or electric vehicle (29) comprising a drive unit (1) according to one of claims 12 to 14 or a motor vehicle drive axle (31) according to claim 15. [17] Method for operating a motor vehicle transmission (3) according to one or more of claims 1 to 11, - wherein a first gear (G1) is switched between the drive shaft (6) and the output shaft (7) by simultaneously displaying actuated states of the third switching element (C) and the fourth switching element (D), - wherein a second gear (G2) is switched between the drive shaft (6) and the output shaft (7) by simultaneously displaying actuated states of the first switching element (A) and the third switching element (C), - and wherein a third gear (G3) is switched between the drive shaft (6) and the output shaft (7) by simultaneously representing actuated states of the first switching element (A) and the second switching element (B).

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