Motor vehicle transmission for a motor vehicle that is at least partially electrically powered

Abstract

Motor vehicle transmission (3) for a motor vehicle that is at least partially electrically powered, comprising a drive shaft (6), an output shaft (7), 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, respectively, wherein the drive shaft (6) is provided for coupling with at least one drive motor, 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 rotationally fixed to each other, and wherein at least functionally a first switching element (A), a second switching element (B), and a third switching element (C) are plannedcharacterized by, , - that the drive shaft (6) is connected to the first element (E12) of the second planetary gear set (P2) in a rotationally fixed manner, - 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 to the drive shaft (6) in a rotationally fixed manner, - that in the actuated state of the at least functionally provided second switching element (B) the output shaft (7) is rotationally fixed 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 rotationally fixed to the second element (E22) of the second planetary gear set (P2).

Description

[0001] The invention relates to a motor vehicle transmission for a motor vehicle that is at least partially electrically powered, comprising a drive shaft, an output shaft, 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, respectively, wherein the drive shaft is provided for coupling with at least one drive motor, 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 rotationally fixed to each other, and wherein at least functionally a first switching element, a second switching element, and a third switching element are provided.Furthermore, the invention relates to a drive unit for a motor vehicle that is at least partially electrically powered, an electrically driven motor vehicle drive axle for a motor vehicle that is at least partially electrically powered, and a hybrid or electric vehicle.

[0002] In electric and hybrid vehicles, a transmission is sometimes integrated into the drivetrain between at least one electric motor and the drive wheels to translate the electric motor's motion, particularly to slower speeds, to the drive wheels. Besides single-gear transmissions, transmissions with two or more gears are also sometimes used.

[0003] German patent application 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 consisting of an electric motor and a motor vehicle transmission. In addition to a drive shaft and an output shaft, the motor vehicle transmission includes two planetary gear sets, each consisting of a sun gear, a planet carrier, and a ring gear. Within the drive unit, a non-rotatable connection to the upstream electric motor is established at the drive shaft, while the output shaft is connected to a differential gear set, which serves to distribute power to the output shafts of the motor vehicle drive axle. Furthermore, the motor vehicle transmission has a switching device which, in one variant of DE 10 2019 202 994 A1, performs the functions of three switching elements.A coupling element of the switching device can assume different switching states and thereby realize different power flow paths from the drive shaft via the planetary gear sets to the output shaft.

[0004] Document DE 10 2019 119 950 B3 discloses a drive device for a motor vehicle with a simple transmission structure featuring many identical parts and a suitable gear ratio distribution or spread. The drive device comprises an electric drive motor operatively connected to a transmission device via a drive shaft. The transmission device includes at least a first and second planetary gear stage, each with a first and second sun gear, as well as a differential stage. The first and second planetary gear stages are operatively connected to a dual-clutch transmission, which includes a first and a second load-shiftable clutch. The first and second sun gears are rotationally fixed to each other, and the drive shaft is operatively connected to both sun gears.

[0005] Starting from the prior art described above, the object of the present invention is to realize a suitable alternative for a motor vehicle transmission.

[0006] This problem is solved starting from the preamble of claim 1 in conjunction with its characterizing features. The subsequent dependent claims each describe advantageous embodiments of the invention. A drive unit comprising a motor vehicle transmission according to the invention is further the subject of claims 12 to 14. Claim 15 relates to an electrically driven motor vehicle drive axle for a motor vehicle that is at least partially electrically driven, 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.

[0007] According to the invention, a motor vehicle transmission comprises a drive shaft, an output shaft, a first planetary gear set, and a second planetary gear set. The first and second planetary gear sets 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, respectively. The drive shaft is designed for coupling to at least one drive motor. The third element of the first planetary gear set is fixed in place. Furthermore, the second element of the first planetary gear set and the third element of the second planetary gear set are rotationally fixed to one another. At least functionally, a first switching element, a second switching element, and a third switching element are also provided.

[0008] In the context of the invention, a "shaft," such as the respective drive shaft or output shaft, is understood to be a rotatable component of the transmission through which power flow between components can be achieved. The shaft can connect the components axially or radially, or both. It can also act as an intermediate piece, connecting a component, for example, purely radially. Furthermore, depending on its shape and connection to the components, or the possibility of connecting to them, the shaft can be designed as a solid shaft, a hollow shaft, or partially as a solid and partially as a hollow shaft. Alternatively or additionally, the shaft can be constructed in one piece or in multiple parts.

[0009] In the context of the invention, "axial" refers to an orientation in the direction of a longitudinal center axis of the vehicle transmission, parallel to which the rotational axes of the transmission shafts and the planetary gear set elements are also oriented. "Radial" refers to an orientation in the diameter direction of a respective transmission component, in particular a respective shaft or planetary gear set element.

[0010] The motor vehicle transmission according to the invention has a drive shaft which, in the motor vehicle transmission according to the invention, is designed to establish a drive-side coupling to at least one drive motor, wherein the drive shaft preferably serves for coupling with exactly one drive motor. For this purpose, the drive shaft is in particular equipped with a connection point at which a coupling of the drive shaft with 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, in particular, permanently established 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., is provided by which the drive shaft can be coupled to the upstream drive motor at its connection point. This is particularly the case when the drive motor is designed as an internal combustion engine.

[0011] The coupling between the at least one drive motor and the drive shaft is preferably configured such that, in the installed state of the vehicle transmission and with the coupling established, a fixed speed ratio always prevails between the rotational speed of the vehicle transmission's drive shaft and the rotational speed of the drive motor. Within the scope of the invention, at least one further transmission stage, such as a spur gear stage and / or a planetary gear stage, may optionally be provided between the drive shaft and the drive motor, through which a pre-transduction of the rotary motion of the drive motor to the drive shaft can be achieved. Preferably, however, the drive shaft serves as a rotationally fixed connection to the at least one drive motor.

[0012] The motor vehicle transmission is in particular a hybrid or electric vehicle transmission designed to be connected to the drive shaft by at least one drive motor in the form of an electric motor. As described above, the rotor of each electric motor can be coupled to the drive shaft of the transmission via at least one intermediate transmission stage. However, it is particularly preferred that, in the installed state of the motor vehicle transmission according to the invention, the rotor of each electric motor is non-rotatably connected to the drive shaft.

[0013] In the motor vehicle transmission according to the invention, the output shaft is specifically designed to provide an output-side coupling between the motor vehicle transmission and components which, in the installed state of the motor vehicle transmission, 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 can be established with the drive wheels of the respective motor vehicle in order to translate a drive motion generated by the at least one drive motor with different gear ratios to the drive wheels.

[0014] The first and second planetary gear sets each consist of a first element, a second element, and a third element, wherein one of these elements is configured as a sun gear, one as a planet carrier, and one as a ring gear. Preferably, each planetary gear set is configured as a negative planetary gear set, in which the respective planet carrier rotatably guides at least one planet gear, with the at least one planet gear meshing with both the respective sun gear and the respective ring gear.In a configuration of the individual planetary gear set as a negative planetary gear set, the first element of each planetary gear set is the sun gear, the second element is the planet carrier, and the third element is the ring gear. In particular, several planet gears are rotatably mounted within the planet carrier.

[0015] Alternatively, one or both planetary gear sets could also be designed as plus planetary gear sets. 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 the other with the respective ring gear. Furthermore, the planetary gears of the at least one planetary gear pair mesh with each other. In contrast to a minus planetary gear set design, the first element of each planetary gear set is preferably the respective sun gear, the second element is the respective ring gear, and the third element is the respective planet carrier. Compared to a minus planetary gear set design, the fixed gear ratio of each planetary gear set is also increased by one.As described above, the first planetary gear set and the second planetary gear set are preferably each a negative planetary gear set.

[0016] In the motor vehicle transmission according to the invention, the input shaft and the output shaft are arranged, in particular, coaxially to each other, with the first planetary gear set and the second planetary gear set also preferably being positioned coaxially to the input shaft and the output shaft. This allows for a particularly compact design of the motor vehicle transmission in the radial direction.

[0017] The invention now comprises the technical teaching that the drive shaft is connected to the first element of the second planetary gear set in a rotationally fixed manner. In the actuated state of the at least functionally provided first switching element, the first element of the first planetary gear set is connected to the drive shaft in a rotationally fixed manner, whereas in the actuated state of the at least functionally provided second switching element, the output shaft is connected to the second element of the second planetary gear set in a rotationally fixed manner. Furthermore, in the actuated state of the at least functionally provided third switching element, the output shaft is connected to the second element of the first planetary gear set and to the third element of the second planetary gear set in a rotationally fixed manner.Furthermore, at least functionally, a fourth switching element is provided, in whose actuated state the first element of the first planetary gear set is rotationally fixed to the second element of the second planetary gear set.

[0018] In the motor vehicle transmission according to the invention, the first element of the second planetary gear set and the drive shaft are permanently and rotationally fixed to one another, so that the first element of the second planetary gear set and the drive 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 and rotationally fixed to one another, causing the second element of the first planetary gear set and the third element of the second planetary gear set to constantly rotate together. The third element of the first planetary gear set is also permanently fixed and thus constantly prevented from rotating.

[0019] In the context of the invention, a permanent "rotationally rigid" connection of transmission components means that these components are permanently and rigidly connected to one another and thus always maintain the same rotational speed. The rotationally rigidly connected components can be separate components that are attached to one another, for example, via an intermediate shaft. Alternatively, the rotationally rigidly connected components can also be manufactured as a single unit and thus exist together as one component, which is particularly the case when these components are arranged in close proximity to one another.

[0020] The motor vehicle transmission according to the invention has, at least functionally, a first switching element, a second switching element, a third switching element, and a fourth switching element to represent different couplings of the drive shaft with the output shaft and thus to switch different transmission ratios between the drive shaft and the output shaft. Particularly preferred for representing the different transmission ratios between the drive shaft and the output shaft are exactly four switching elements in the form of the first switching element, the second switching element, the third switching element, and the fourth switching element. That a respective switching element is provided "at least functionally" means, within the meaning of the invention, that the respective function of the respective switching element is represented in the motor vehicle transmission according to the invention.The individual switching element can either exist physically as a separate switching element, or its function can be represented by another component, such as a switching device. A single component representing the function can then combine the functions of two or more switching elements within one device.

[0021] The representation of an actuated state of the first switching element results in the first element of the first planetary gear set and the drive shaft being rotationally fixed to each other. This leads to a joint rotation of the first element of the first planetary gear set with the drive shaft and thus also with the first element of the second planetary gear set when the first switching element is actuated (at least functionally intended). Conversely, if the actuated state of the second switching element is realized, the output shaft and the second element of the second planetary gear set are rotationally fixed to each other and therefore rotate together when the second switching element is actuated.

[0022] By realizing the actuated state of the third switching 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 each other in a rotationally fixed manner. As a result, the output shaft, the second element of the first planetary gear set, and the third element of the second planetary gear set rotate together when the third switching element is actuated. Furthermore, the first element of the first planetary gear set can also be connected to the second element of the second planetary gear set in a rotationally fixed manner, thus representing the actuated state of the fourth switching element.

[0023] Within the scope of the invention, fixing a component of the motor vehicle transmission via an at least functionally provided switching element, or a rotationally fixed connection between components of the motor vehicle transmission via an at least functionally provided switching element, means that the component in question is not permanently fixed, nor are the components permanently coupled to one another. Rather, fixing or a rotationally fixed connection is only achieved by establishing an actuated state of the at least functionally provided, intermediate switching element. An actuated state of the at least functionally provided switching element, as defined in the invention, means that the switching element is in a closed state, and consequently, the rotational movements of the components directly connected to it are synchronized.If at least the function of a positive-locking switching element is depicted, the components directly and rotationally fixedly connected to each other will operate at the same speed, whereas in the case of depicting at least the function of a friction-locking switching element, speed differences between the components may exist even after the actuated state of the same is shown. 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.

[0024] A fixed state of a component of the motor vehicle transmission is achieved, in accordance with the invention, in particular by a rotationally fixed connection with a permanently stationary component, which may be a housing of the motor vehicle transmission, a part of the housing, or a component permanently and rotationally fixed to it. The third element of the first planetary gear set is permanently and rotationally fixed to this permanently stationary component, whereby a one-piece embodiment of the third element of the first planetary gear set and the permanently stationary component could also be implemented.

[0025] The inventive design of a motor vehicle transmission has the advantage that a compact motor vehicle transmission can be realized. Furthermore, in this motor vehicle transmission, gear ratios can be selected between the input shaft and the output shaft, which are suitable for integrating a drive motor, particularly one designed as an electric motor.

[0026] A first gear can be engaged between the input shaft and the output shaft by simultaneously acting the states of the third and fourth switching elements. A second gear is achieved between the input shaft and the output shaft by simultaneously acting the states of the first and third switching elements. Furthermore, a third gear can be engaged between the input shaft and the output shaft by simultaneously acting the states of the first and second switching elements. This allows for a suitable shifting sequence, whereby, in each successive shift of gears, only the switching state of two of the functionally provided switching elements needs to be changed.

[0027] According to one embodiment, the first switching element and the fourth switching element are formed by a common switching device which includes a coupling element. This coupling element can be switched to a first switching state and a second switching state, wherein in the first switching state the coupling element functionally represents the actuated state of the first switching element and connects the first element of the first planetary gear set to the drive shaft in a rotationally fixed manner. In its second switching state, however, the coupling element functionally represents the actuated state of the fourth switching element and connects the first element of the first planetary gear set to the second element of the second planetary gear set in a rotationally fixed manner. In this case, the function of the first switching element and the fourth switching element is thus represented by a common switching device, which enables a particularly compact arrangement.Furthermore, this allows for the provision of an actuating mechanism for the switching elements, enabling the coupling element to be switched between its different 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.

[0028] In a further development of the aforementioned embodiment, the coupling element is guided in both switching states and during axial displacement between the two switching states by a first toothed section, which is rotationally fixed and axially displaceable. This first toothed section is rotationally fixed to the first element of the first planetary gear set. In its first switching state, the coupling element, when the teeth are engaged with the first toothed section, additionally engages a second toothed section, which is rotationally fixed to the drive shaft. Furthermore, in the second switching state, when the teeth are engaged with the first toothed section, the coupling element also engages a third toothed section, which is rotationally fixed to the second element of the second planetary gear set.The coupling element of the switching device is particularly preferably designed as a sliding sleeve, with the toothing preferably being configured as claw teeth, so that the switching device replicates the function of unsynchronized claw switching elements. Within the scope of the invention, however, the first switching element and the fourth switching element could also be configured as individual switching elements, wherein the first switching element and the fourth switching element could each be configured as a positive-locking switching element, such as a claw switching element or locking synchronization, or as a friction-locking switching element, for example as a lamellar switching element.

[0029] Alternatively, but preferably in addition to the aforementioned embodiment and its further development, the second switching element and the third switching element are formed by a common switching device which includes a coupling element. The coupling element of this switching device can be switched into a first switching state and a second switching state, wherein in the first switching state the coupling element functionally represents the actuated state of the second switching element and connects the output shaft rotationally fixed to the second element of the second planetary gear set. In its second switching state, the coupling element functionally represents the actuated state of the third switching element and connects the output shaft rotationally fixed to the second element of the first planetary gear set and the third element of the second planetary gear set.Advantageously, this allows the switching device to represent the function of the second and third switching elements, thus requiring only one actuator in addition to a compact arrangement. In particular, the coupling element can then be moved into a neutral state in addition to the two switching states, 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.

[0030] Preferably, the coupling element is guided in both switching states and during axial displacement between the two switching states by a first toothed section, which is rotationally fixed and axially displaceable. This first toothed section is rotationally fixed to the output shaft. When the coupling element is in its first switching state, it engages with the first toothed section and, while the teeth are engaged, also engages with a second toothed section, which is rotationally fixed to the second element of the second planetary gear set. In the second switching state, the coupling element engages with the first toothed section and, while the teeth are engaged with the first toothed section, also engages with a third toothed section, which is rotationally fixed to both the first and third elements of the second planetary gear set.Particularly preferred is the coupling element of the switching device designed as a sliding sleeve, with the toothing being specifically designed as claw teeth, so that the switching device replicates the function of unsynchronized claw switching elements. Alternatively, the second and third switching elements can also be designed as individual switching elements. In this case, the second and third switching elements can each be designed as a positive-locking switching element, such as a claw switching element or locking synchronization, or as a friction-locking switching element, for example, as a lamellar switching element.

[0031] Particularly preferably, the two switching devices described above are implemented together in the vehicle transmission according to the invention, so that the functions of the first, second, third, and fourth switching elements can be represented by two switching devices via the associated coupling elements. This allows for a particularly compact design of the vehicle transmission. Within the scope of the invention, each "switching state" or "neutral state" of the respective coupling element can be assigned a discrete axial position of the respective coupling element, wherein the respective "switching state" or "neutral state" is preferably defined by an axial adjustment range within which the coupling element must be positioned to realize the respective switching state or neutral state.

[0032] 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, where the drive shaft is coupled to the at least one drive motor. This allows for a suitable design of the motor vehicle transmission according to the invention.

[0033] In a further development of the aforementioned embodiment, the first switching element and / or the fourth switching element, which are at least functionally provided, are arranged axially between the first planetary gear set and the second planetary gear set. If the functions of the first switching element and the fourth switching element are implemented by a common switching device, this switching device is then preferably positioned axially between the planetary gear sets.

[0034] Alternatively, but preferably additionally, the second switching element and / or the third switching element, which are at least functionally provided, are each arranged axially on a side of the second planetary gear set facing away from the first. If a switching device is provided by which the functions of the second and third switching elements are implemented, this switching device is then placed axially on the side of the second planetary gear set facing away from the first.

[0035] In one embodiment of the invention, the output shaft is coupled to an input element of a differential gear set, which in turn couples the output shaft to two output shafts. This effectively couples the output shaft to the two output shafts via the differential gear set. Advantageously, this allows the distribution of a drive torque generated at the output shaft to the two output shafts, while also enabling speed compensation between the output shafts via the differential gear set. The differential gear set functions particularly as a transverse differential and is preferably designed as a bevel gear differential. The transverse differential thus formed preferably distributes the drive motion transmitted to the output shaft of the vehicle transmission to the output shafts, which are preferably assigned to a vehicle drive axle.The differential gear set can also function as a longitudinal differential, allowing the distribution of drive power to multiple drive axles. As an alternative to a bevel gear differential, the differential gear set, according to the invention, can also be designed as a planetary gear differential, a spur gear differential, etc.

[0036] The input element to which the output shaft is coupled is preferably a differential carrier of the differential gear set. When the differential gear set is used as a transverse differential and the vehicle transmission is installed transversely to one direction of travel of the associated vehicle, the output shaft is preferably connected to the input element in a rotationally fixed manner. This is also particularly the case when the differential gear set functions as a longitudinal differential and the vehicle transmission is oriented in the direction of travel of the vehicle. However, when the 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 gear.Such a bevel gear is also preferably used when the differential gear set is a longitudinal differential and the vehicle transmission is oriented transversely to the direction of travel.

[0037] In a further development of the aforementioned embodiment, the differential gear set is axially overlapping with the second planetary gear set and is positioned radially inside both planetary gear sets. However, according to the invention, the differential gear set could also be provided axially between the first and second planetary gear sets, in which case the differential gear set would be positioned radially inside the planetary gear sets. This allows, particularly when using the vehicle transmission according to the invention in a vehicle drive axle, an advantageous positioning of the differential gear set near the center between the axle's drive wheels.Alternatively, the differential gear set can also be arranged axially on a side of the first planet gear set facing away from the second planet gear set, or axially on a side of the second planet gear set facing away from the first planet gear set, whereby the differential gear set is preferably always provided radially inside the two planet gear sets.

[0038] Alternatively or additionally to the aforementioned further development, the output shafts are each coupled to the differential gear set via an intermediate transmission stage. Advantageously, the overall gear ratio achievable via the vehicle transmission can be changed by means of these additional transmission stages. The transmission stages can preferably be designed as planetary gear sets.

[0039] The invention further relates to a drive unit comprising an electric machine and a motor vehicle transmission according to one or more of the variants described above. A rotor of the electric machine is coupled to the drive shaft of the motor vehicle transmission. Within the scope of the invention, the electric machine can be operated, in particular, as a generator and as an electric motor. This allows for the creation of a drive unit suitable for use in a motor vehicle, such as an electric or hybrid vehicle.

[0040] In this drive unit according to the invention, the first planetary gear set or the second planetary gear set, or both the first and the second planetary gear set, can be arranged axially at least overlapping and radially inside the electric machine. This allows for a compact design of the drive unit. "Axially at least overlapping" means that at least a part of the first planetary gear set and / or the second planetary gear set lies axially in a plane with at least a part of the electric machine.

[0041] The rotor of the electric motor can be fixedly connected to the drive shaft of the vehicle transmission, in which case the electric motor is arranged coaxially to the drive shaft. This ensures that the drive shaft and the rotor of the electric motor rotate at the same speed during operation. Alternatively, the rotor of the electric motor can be fixedly connected to an intermediate shaft of the vehicle transmission, which is coupled to the drive shaft via at least one transmission stage. In this case, the electric motor may be offset from the drive shaft. Depending on the design of the at least one transmission stage, a coaxial arrangement of the electric motor to the drive shaft is also possible.

[0042] A drive unit designed according to one of the aforementioned variants is, in particular, part of an electrically driven vehicle drive axle, which is intended for use in an electric or hybrid vehicle. Preferably, the vehicle transmission has a differential gear set that is coupled to the output shaft and, in turn, couples the output shaft to output shafts. Each of the output shafts is assigned to a drive wheel of the vehicle drive axle.

[0043] The aforementioned motor vehicle drive axle is provided within the scope of the invention for a hybrid or electric vehicle, which may be a passenger car or a commercial vehicle. A commercial vehicle may be a van with at least partial electric drive or a light to medium-weight bus or truck.

[0044] An advantageous embodiment of the invention, which is explained below, is illustrated in the drawings. They show: Fig. 1 a schematic view of a drive unit according to an embodiment of the invention; Fig. 2 an exemplary switching diagram of a motor vehicle transmission of the drive unit Fig. 1; and Fig. 3 A schematic view of an electric vehicle according to a preferred embodiment of the invention.

[0045] Out of Fig. Figure 1 shows a schematic view of a drive unit 1, which is designed according to one embodiment of the invention. This drive unit 1 comprises an electric machine 2 and a motor vehicle transmission 3, which is designed according to one embodiment of the invention. The electric machine 2 is formed by a stator 4 and a rotor 5 in a manner known to those skilled in the art, and the electric machine 2 can be operated both as a generator and as an electric motor.

[0046] The motor vehicle transmission 3 has, in addition to a drive shaft 6 and an output shaft 7, two planetary gear sets P1 and P2, each consisting of a first element E11 or E12, a second element E21 or E22, and a third element E31 or E32. The first element E11 or E12 of each planetary gear set P1 or P2 is a sun gear, while the second element E21 or E22 is a planet carrier. The third element E31 or E32 of each planetary gear set P1 or P2 is a ring gear.

[0047] In each planet carrier of the respective planet gear set P1 or P2, at least one planet gear is rotatably mounted, which meshes with both the respective sun gear and the respective ring gear of the respective planet gear set P1 or P2. In this respect, the planet gear sets P1 and P2 are designed as negative planet sets. However, within the scope of the invention, an embodiment of one or both planet gear sets P1 and P2 as a positive planet set is also possible. In this embodiment, compared to the respective negative planet set, the respective second element E21 or E22 is formed by the respective ring gear, and the respective third element E31 or E32 is formed by the respective planet carrier. Furthermore, the gear ratio in the positive planet set is increased by one compared to the negative planet set.In a plus planetary gear set, at least one pair of planet gears is rotatably mounted in the respective planet carrier, with one planet gear meshing with the respective sun gear and the other with the respective ring gear. Furthermore, the planet gears of the at least one planet gear pair mesh with each other.

[0048] In this invention, the first element E12 of the second planetary gear set P2 is non-rotatably connected to the drive shaft 6, which is also non-rotatably connected to the rotor 5 of the electric machine 2 at a connection point 8. Therefore, the first element E12 of the second planetary gear set P2 and the rotor 5 are also non-rotatably connected to each other via the drive shaft 6, ensuring that the first element E12 and the rotor 5 always rotate at the same speed. According to the invention, the drive shaft 6 can be integrally formed with the rotor 5 of the electric machine 2 and / or with the first element E12 of the second planetary gear set P2.

[0049] The second element E21 of the first planetary gear set P1 is permanently and rotationally fixedly connected 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 rotationally fixed to both the second element E21 of the first planetary gear set P1 and 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.

[0050] Furthermore, the first element E11 of the first planetary gear set P1 is non-rotatably connected to a shaft 10, which is a radial shaft section and preferably formed integrally 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. In addition, 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. Consequently, the third element E31 of the first planetary gear set P1 is permanently prevented from rotating.

[0051] The output shaft 7 is rotationally fixed to an input element 13 of a differential gear set 14, which is preferably designed as a bevel gear differential and distributes a drive torque introduced into the input element 13 via the output shaft 7 to two output shafts 15 and 16 in a manner known in principle to those skilled in the art. The two output shafts 15 and 16 are each coupled to the differential gear set 13 via an intermediate transmission stage 17 or 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 transmission stages 17 and 18 – shown here only schematically – are preferably designed as planetary gear sets.

[0052] The motor vehicle transmission 3 also has two switching devices 19 and 20. Switching device 19 includes a coupling element 21 in the form of a sliding sleeve, which is guided non-rotatably and axially displaceably on a toothed section 22. The toothed section 22 is formed on the shaft 10 and is thus non-rotatably connected to the first element E11 of the first planetary gear set P1. Axially, displacements of the coupling element 21 on the toothed section 22 can be effected by an actuator (not shown here), which is preferably designed as an electromechanical actuator.

[0053] The coupling element 21 can be moved axially between two different switching states via the actuator under constant guidance at the toothing 22, whereby in each of the switching states, the coupling element 21 engages with a corresponding toothing 23 or 24. The toothing 23 is rotationally fixed 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 rotationally fixed to the second element E22 of the second planetary gear set P2 and is provided for this purpose on the shaft 11.

[0054] The switching device 19 represents the function of two switching elements A and D, whose respective actuated states are represented by the switching device 19 in one of the switching states of the coupling element 21. Thus, an actuated state of switching element A is realized in a first switching state of the coupling element 21, in which the coupling element 21, with existing tooth engagement with the toothing 22, additionally engages the toothing 23. This results in a rotationally fixed connection of the shaft 10 with the drive shaft 6 and thus also of the first element E11 of the first planetary gear set P1 with the first element E12 of the second planetary gear set P2.

[0055] From the first switching state, the coupling element 21 can be transferred to a neutral state via the actuator, which is in Fig. Figure 1 shows the coupling element 21 in which it is only engaged with the toothing 22. Therefore, 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.

[0056] In addition to transitioning the coupling element 21 into its first switching state, it can also be moved from the neutral state into a second switching state. In this second state, the coupling element 21 engages not only with the toothing 22 but also with the toothing 24. This connects the shafts 10 and 11 to each other 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. The second switching state of the coupling element 21 corresponds to an actuated state of the switching element D.

[0057] The switching device 20 also has a coupling element 25 in the form of a sliding sleeve, wherein the coupling element 25 is guided rotationally fixed and axially displaceable on a toothed section 26 which is formed on the output shaft 7. From a in Fig. In the neutral state shown in Figure 1, in which the coupling element 25 does not couple the output shaft 7, the coupling element 25 can be axially switched to a first switching state via an associated actuator (not shown here). In this first switching state, the coupling element 25, with its tooth mesh 26, engages with a tooth 27 formed on the shaft 11, thus forming a rotationally fixed connection with the second element E22 of the second planetary gear set P2. This results in a rotationally fixed connection between the output shaft 7 and the shaft 11, and therefore also with the second element E22 of the second planetary gear set P2, in the first switching state of the coupling element 25. In this first switching state of the coupling element 25, an actuated state of a switching element B is represented.

[0058] On the other hand, the coupling element 25 can also be axially transferred from the neutral state to a second switching state via the associated actuator, in which the coupling element 25, with existing tooth engagement with the toothing 26, additionally engages with a toothing 28. This toothing 28 is formed on the shaft 9 and is thus rotationally fixed to the second element E21 of the first planetary gear set P1 and the third element E32 of the second planetary gear set P2. This creates a rotationally fixed connection between the shaft 9, and thus also between the second element E21 of the first planetary gear set P1 and the third element E32 of the second planetary gear set P2, and the output shaft 7 in the second switching state of the coupling element 25. As a result, 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.

[0059] In this case, the electric machine 2 is positioned coaxially with the motor vehicle transmission 3, in which the drive 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. Following the connection of the drive shaft 6 to the rotor 5 of the electric machine 2 at its connection point 8, the two planetary gear sets P1 and P2 are then arranged axially in the sequence 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 inside the first planetary gear set P1.Furthermore, the switching device 20, which represents the two switching 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 switching device 20 is positioned radially essentially at the level of the first element E12 of the second planetary gear set P2.

[0060] The differential gear set 14 is axially overlapping with the second planetary gear set P2 and 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.

[0061] 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, a total of three different gear ratios in the form of gears G1, G2, and G3 can be engaged between the input shaft 6 and the output shaft 7 in the motor vehicle transmission 3. 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 respective gear.

[0062] As in Fig. As can be seen in Figure 2, a first gear G1 is engaged between the drive shaft 6 and the output shaft 7 by displaying the actuated state of switching element D at switching device 19 and simultaneously the actuated state of switching element C at switching device 20. To engage a second gear G2, the actuated state of switching element C must still be displayed at switching device 20, while simultaneously the actuated state of switching element A must be displayed at switching device 19. Finally, a third gear G3 is engaged between the drive shaft 6 and the output shaft 7 by displaying the actuated state of switching element A at switching device 19 and simultaneously the actuated state of switching element B at switching device 20.

[0063] Finally, it also shows Fig.Figure 3 shows a schematic view of an electric vehicle 29, which may be, in particular, 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 vehicle drive axle 31 with drive wheels 32 and 33. The drive unit 1 is also part of the vehicle drive axle 31. 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.

[0064] While vehicle axle 30 is a front axle of the electric vehicle 29, the vehicle drive axle 31 is a rear axle of the electric vehicle 29. However, alternatively or additionally to the vehicle drive axle 31, vehicle axle 30 could also be designed as a driven axle with a possibly analogous drive unit design.

[0065] Using the embodiments according to the invention, a compact motor vehicle transmission can be realized which is suitable for the integration of an electric motor. Reference sign 1 drive unit 2 Electric machine 3 Motor vehicle transmissions 4 Stator 5 Rotor 6 Drive shaft 7 Output wave 8 Junction 9th wave 10 wave 11th wave 12 fixed building element 13 Entrance element 14 Differential gear set 15 Output shaft 16 Output shaft 17th translation level 18 translation level 19 Switching device 20 Switching device 21 coupling element 22 gearing 23 Gearing 24 teeth 25 coupling element 26 gear teeth 27 Gearing 28 gear teeth 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 first planetary gear set E21 Second element first planetary gear set E31 Third element first planetary gear set E12 First element second planetary gear set E22 Second element second planetary gear set E32 Third element second planetary gear set A switching element B Switching element C switching element D Switching element G1 gear G2 gear G3 gear

Claims

[1] Motor vehicle transmission (3) for a motor vehicle that is at least partially electrically powered, comprising a drive shaft (6), an output shaft (7), 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 respectively, wherein the drive shaft (6) is provided for coupling with at least one drive motor 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 rotationally fixed to each other, and wherein at least functionally a first switching element (A), a second switching element (B) and a third switching element (C) are provided for,, characterized by , - that the drive shaft (6) is connected to the first element (E12) of the second planetary gear set (P2) in a rotationally fixed manner, - 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 to the drive shaft (6) in a rotationally fixed manner, - that in the actuated state of the at least functionally provided second switching element (B) the output shaft (7) is rotationally fixed 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 rotationally fixed to the second element (E22) of the second planetary gear set (P2). [2] Motor vehicle transmission (3) according to claim 1, characterized by, that the first switching element (A) and the fourth switching element (D) are formed by a common switching device (19) which has a coupling element (21), wherein the coupling element (21) can be converted into a first switching state and into a second switching state, wherein in the first switching state the coupling element (21) functionally represents the actuated state of the first switching element (A) and connects the first element (E11) of the first planetary gear set (P1) to the drive shaft (6) in a rotationally fixed manner, and wherein in the second switching state the coupling element (21) functionally represents an actuated state of the fourth switching element (D) and connects the first element (E11) of the first planetary gear set (P1) to the second element (E22) of the second planetary gear set (P2) in a rotationally fixed manner. [3] Motor vehicle transmission (3) according to claim 2, characterized by, that the coupling element (21) is guided in both switching states and during axial displacement between the two switching states in a rotationally fixed and axially displaceable manner on a first toothing (22), which is rotationally fixed to the first element (E11) of the first planetary gear set (P1), wherein in the first switching state, with existing tooth engagement with the first toothing (22), the coupling element (21) additionally engages in a second toothing (23), which is rotationally fixed to the drive shaft (6), and wherein in the second switching state, with existing tooth engagement with the first toothing (22), the coupling element (21) additionally engages in a third toothing (24), which is rotationally fixed to the second element (E22) of the second planetary gear set (P2). [4] Motor vehicle transmission (3) according to any 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 converted into a first switching state and into a second switching state, wherein in the first switching state the coupling element (25) functionally represents the actuated state of the second switching element (B) and connects the output shaft (7) rotationally fixed to the second element (E22) of the second planetary gear set (P2), and wherein in the second switching state the coupling element (25) functionally represents the actuated state of the third switching element (C) and connects the output shaft (7) rotationally fixed 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 by, that the coupling element (25) is guided in both switching states and during axial displacement between the two switching states in a rotationally fixed and axially displaceable manner on a first toothing (26) which is rotationally fixed to the output shaft (7), wherein in the first switching state, with existing tooth engagement with the first toothing (26), the coupling element (25) additionally engages in a second toothing (27) which is rotationally fixed to the second element (E22) of the second planetary gear set (P2), and wherein in the second switching state, with existing tooth engagement with the first toothing (26), the coupling element (25) additionally engages in a third toothing (28) which is rotationally fixed 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 any one of the preceding claims, characterized by, that the planetary gear sets (P1, P2) are arranged axially in a sequence 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) with 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 switching element (A) and / or the at least functionally provided fourth switching 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 switching element (B) and / or the at least functionally provided third switching 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 any 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 planet gear set (P2) and radially inside the planet 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 transmission stage (17, 18). [12] Drive unit (1) for a motor vehicle that is at least partially electrically powered, 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 and radially inside 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 a motor vehicle that is at least partially electrically driven, comprising a drive unit (1) according to any one of claims 12 to 14. [16] Hybrid or electric vehicle (29) comprising a drive unit (1) according to any 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 engaged between the drive shaft (6) and the output shaft (7) by representing simultaneously actuated states of the third switching element (C) and the fourth switching element (D), - wherein a second gear (G2) is engaged between the drive shaft (6) and the output shaft (7) by representing simultaneously actuated states of the first switching element (A) and the third switching element (C), - and wherein a third gear (G3) is engaged between the drive shaft (6) and the output shaft (7) by representing simultaneously actuated states of the first switching element (A) and the second switching element (B).

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