DE102023203098A1 - Motor vehicle transmission for an at least partially electrically powered motor vehicle - Google Patents

Abstract

The invention relates to a motor vehicle transmission (3), comprising a drive shaft (6), an output shaft (7) and a first planetary gear set (P1), a second planetary gear set (P2) and a third planetary gear set (P3), wherein the drive shaft (6) is provided for coupling to at least one drive machine. Furthermore, at least functionally, a first shifting element (A), a second shifting element (B), a third shifting element (C) and a fourth shifting element (D) are provided. The invention further relates to a drive unit (1), an electrically drivable motor vehicle drive axle, a hybrid or electric vehicle and a method for operating a motor vehicle transmission.

Description

The invention relates to a motor vehicle transmission for an at least partially electrically driven motor vehicle, in particular for an electrically drivable motor vehicle drive axle, comprising a drive shaft, an output shaft and a first planetary gear set, a second planetary gear set and a third planetary gear set, wherein the drive shaft is provided for coupling to at least one drive machine, wherein the first planetary gear set, the second planetary gear set and the third 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 at least functionally a first switching element, a second switching element and a third switching element are provided, and wherein the first element of the first planetary gear set is connected to the drive shaft in a rotationally fixed manner. The invention further relates to a drive unit for an at least partially electrically driven motor vehicle, an electrically drivable motor vehicle drive axle for an at least partially electrically driven motor vehicle, a hybrid or electric vehicle and a method for operating a motor vehicle transmission.

In the case of motor vehicles designed as electric and hybrid vehicles, a motor vehicle transmission is sometimes provided in a respective drive train between at least one electric machine and the drive wheels of the respective motor vehicle in order to be able to translate a drive movement of the at least one electric machine, in particular at a lower speed, to the drive wheels. In addition to single-speed transmissions, motor vehicle transmissions are also sometimes used in which two or more gears can be engaged.

From the DE 10 2017 006 262 A1 A motor vehicle transmission is produced which is intended for use in an electric vehicle. In addition to a drive shaft and an output shaft, this motor vehicle transmission comprises three planetary gear sets, each of which is made up of elements in the form of a sun gear, a planet carrier and a ring gear. When the motor vehicle transmission is installed, the drive shaft serves to connect to an upstream electric machine. In addition, the motor vehicle transmission has three switching elements which are designed as force-locking switching elements and whose selective actuation can be used to create different power flow guides from the drive shaft via the planetary gear sets to the output shaft.

Based on the prior art described above, it is now the object of the present invention to provide an axially compact motor vehicle transmission by means of which at least one drive machine can be integrated in a suitable manner.

This object is achieved on the basis of the preamble of claim 1 in conjunction with its characterizing features. The dependent claims that follow thereon each reflect advantageous developments of the invention. A drive unit in which a motor vehicle transmission according to the invention is provided is also the subject of claims 11 and 12. Furthermore, claim 13 relates to an electrically drivable motor vehicle drive axle for an at least partially electrically driven motor vehicle, while claim 14 relates to a hybrid or electric vehicle. Finally, claims 15 to 17 each relate to a method for operating a motor vehicle transmission according to the invention.

According to the invention, a motor vehicle transmission comprises a drive shaft, an output shaft and a first planetary gear set, a second planetary gear set and a third planetary gear set. The drive shaft is provided for coupling to at least one drive machine. In addition, the first planetary gear set, the second planetary gear set and the third 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. At least functionally, a first switching element, a second switching element and a third switching element are provided.

A respective "shaft", such as the drive shaft and the output shaft of the motor vehicle transmission according to the invention, is to be understood in the sense of the invention as a rotatable component of the motor vehicle transmission, via which a force flow can be guided between components. The respective shaft can connect these components to one another axially or radially or even both axially and radially when the force flow is guided. The respective shaft can also be in the form of an intermediate piece, via which a respective component is connected purely radially, for example. Furthermore, depending on the course and connection to the components, the respective shaft can be designed as a solid shaft, as 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.

In the sense of the invention, “axial” means an orientation in the direction of a longitudinal central axis of the Motor vehicle transmission, parallel to which the axes of rotation of shafts of the motor vehicle transmission and the elements of the planetary gear sets are oriented. “Radial” is then understood to mean 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.

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

The coupling between the at least one drive machine 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 machine. Thus, within the scope of the invention, at least one further transmission stage, such as a spur gear stage and/or a planetary stage, can be provided between the drive shaft and the drive machine, via which a pre-transmission of a rotary movement of the drive machine to the drive shaft can be represented. Preferably, however, the drive shaft serves as a rotationally fixed connection to the at least one drive machine.

The motor vehicle transmission is in particular a hybrid or electric vehicle transmission which is intended to be connected to the drive shaft with a drive machine in the form of an electric machine. A rotor of the electric machine can, as described above, be coupled to the drive shaft of the transmission via at least one intermediate gear stage. However, a rotor of the electric machine 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.

In the motor vehicle transmission according to the invention, the output shaft is particularly intended to establish an output-side coupling of the motor vehicle transmission to components which, in the installed state of the motor vehicle transmission, follow the motor vehicle transmission in the direction of power flow to drive wheels of the respective motor vehicle.

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, the second planetary gear set and the third planetary gear set also preferably being placed coaxially to the drive shaft and the output shaft. This makes it possible to achieve a particularly compact structure of the motor vehicle transmission in the radial direction.

The first planetary gear set, the second planetary gear set and the third planetary gear set are each made up of a first element, a second element and a third element, with one element of each of these elements being designed as a sun gear, one element as a planet carrier and one element as a ring gear. The individual planetary gear set is preferably a minus planetary gear set, in which the respective planet carrier guides at least one planetary gear in a rotatable manner, with the at least one planetary gear meshing with both the respective sun gear and the respective ring gear. If the individual planetary gear set is designed as a minus planetary gear set, the first element of the respective planetary gear set is the respective sun gear, the second element of the respective planetary gear set is the respective planet carrier and the third element of the respective planetary gear set is the respective ring gear. In particular, several planetary gears are rotatably mounted in the respective planet carrier.

Alternatively, one or more of the 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, of which one planetary gear is connected to the respective sun gear and one planetary gear is connected to the the respective ring gear is in tooth engagement. In addition, the planet gears of the at least one planet gear pair 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, a stationary gear ratio of the respective planetary gear set is also to be increased by one. As already described above, however, the first planetary gear set, the second planetary gear set, and the third planetary gear set are each preferably a minus planetary gear set.

The invention now includes the technical teaching that the first element of the first planetary gear set is connected to the drive shaft in a rotationally fixed manner, while the second element of the first planetary gear set and the first element of the third planetary gear set are connected to one another in a rotationally fixed manner. In addition, the third element of the first planetary gear set and the first element of the second planetary gear set are connected to one another in a rotationally fixed manner. Furthermore, both the second element of the second planetary gear set and the third element of the third planetary gear set are each fixed. The second element of the third planetary gear set is connected to the output shaft in a rotationally fixed manner. In the actuated state of the at least functionally provided first switching element, the third element of the second planetary gear set is connected to a shaft in a rotationally fixed manner, which in the actuated state of the at least functionally provided second switching element is connected to the third element of the first planetary gear set and the first element of the second planetary gear set. In the actuated state of the at least functionally provided third switching element, the shaft is also connected in a rotationally fixed manner to the second element of the first planetary gear set and the first element of the third planetary gear set, wherein a fourth switching element is also provided, at least functionally, in the actuated state of which the shaft is connected in a rotationally fixed manner to the output shaft.

Such a design of a motor vehicle transmission has the advantage that, through the coupling of the three planetary gear sets to one another according to the invention and by representing the respectively actuated states of the at least functionally provided shifting elements, different gears can be realized, which are particularly suitable for the integration of a drive machine in the form of an electric machine. Power flow guidance in the different gears takes place via the shaft, which can be integrated differently within the motor vehicle transmission via the at least functionally provided shifting elements, but is otherwise freely rotatable when the shifting elements are not actuated. This can be realized in a compact manner and also with low manufacturing costs.

In the motor vehicle transmission according to the invention, a first gear can be switched between the drive shaft and the output shaft by simultaneously displaying the states of the first shifting element and the third shifting element. Furthermore, a second gear is created between the drive shaft and the output shaft by simultaneously displaying the states of the first shifting element and the fourth shifting element. A third gear between the drive shaft and the output shaft can be created by simultaneously displaying the states of the second shifting element and the fourth shifting element. In this way, three different gears can advantageously be switched between the drive shaft and the output shaft, which, with a suitable choice of stationary gear ratios of the planetary gear sets, are suitable for the integration of a drive machine in the form of an electric machine.

Optionally, an additional gear can also be switched between the drive shaft and the output shaft by simultaneously displaying the states of the second shifting element and the third shifting element. A gear ratio in this additional gear would be lower than in the third gear, so that this additional gear can possibly be used as the fourth gear of the motor vehicle transmission. Alternatively or in addition to this, a further gear can also be displayed between the drive shaft and the output shaft by simultaneously displaying the states of the first shifting element and the second shifting element. A gear ratio of this further gear would be between the second gear and the third gear.

For the purposes of the invention, a “torsion-proof connection” of components of the transmission means that these components that are connected to one another in a rotationally fixed manner or are connected to one another in a rotationally fixed manner are rigidly connected to one another and thus always have the same speed. The components that are connected to one another in a rotationally fixed manner or are connected to one another in a rotationally fixed manner can be present as separate components that are attached to one another. Alternatively, components that are connected to one another in a rotationally fixed manner or are connected to one another in a rotationally fixed manner can also be made in one piece. and thus exist together as one component, whereby this is particularly the case when these components are arranged spatially close to one another.

In this case, the first element of the first planetary gear set and the drive shaft are permanently connected to one another in a rotationally fixed manner, so that the first element of the first planetary gear set and the drive shaft always rotate together. Furthermore, the second element of the first planetary gear set and the first element of the third planetary gear set are permanently connected to one another in a rotationally fixed manner and therefore always rotate together. The third element of the first planetary gear set and the first element of the second planetary gear set are permanently connected to one another in a rotationally fixed manner and therefore always rotate together. In addition, there is a permanent, rotationally fixed connection between the second element of the third planetary gear set and the output shaft, so that the second element of the third planetary gear set and the output shaft always have the same speed. Furthermore, the second element of the second planetary gear set is permanently prevented from rotating, for which purpose the second element of the second planetary gear set is permanently fixed. Likewise, the third element of the third planetary gear set is constantly stationary because the third element of the third planetary gear set is permanently fixed.

Within the scope of the invention, a fixed state of a component of the motor vehicle transmission is achieved 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 to it in a rotationally fixed manner. In the case of a permanently fixed state, the respective component could also be designed as one piece with the fixed component. In the present case, the second element of the second planetary gear set and/or the third element of the third planetary gear set could also be formed by a permanently fixed component.

The motor vehicle transmission according to the invention has at least a first shifting element, a second shifting element, a third shifting element and a fourth shifting element, with the motor vehicle transmission according to the invention preferably having exactly four shifting elements, at least in terms of function. The fact that a respective shifting element is provided "at least functionally" means in the sense 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 shifting elements can actually be physically present as a single shifting element or their function is represented by another component, such as a switching device. A component that represents the function can then combine the function of two or more shifting elements in one device.

A representation of an actuated state of the at least functionally provided switching element results in the third element of the second planetary gear set being connected to the shaft in a rotationally fixed manner. If an actuated state of the at least functionally provided second switching element is shown, a rotationally fixed connection is established between the shaft and the third element of the first planetary gear set and the first element of the second planetary gear set. When the actuated state of the at least functionally provided third switching element is shown, the shaft is connected in a rotationally fixed manner to the second element of the first planetary gear set and the first element of the third planetary gear set, whereas an actuated state of the at least functionally provided fourth switching element results in a rotationally fixed connection of the shaft to the output shaft.

In the context of the invention, an arrangement of an at least functionally provided switching element between two components means that these components are not permanently coupled to one another, but rather that a coupling is only made by displaying an actuated state of the at least functionally provided, intermediate switching element. In this case, an actuated state of the at least functionally provided switching element within the meaning of the invention means that the switching element in question is transferred to a closed state and subsequently adjusts the rotational movements of the components directly coupled to it. If at least the function of a positive switching element is depicted, the components directly connected to one another in a rotationally fixed manner will run at the same speed, while in the case of a depiction of at least the function of a non-positive switching element, speed differences between the components can exist even after displaying an actuated state of the same. This intended or unintended state is nevertheless referred to in the context of the invention as a rotationally fixed connection of the respective components via the at least functionally provided switching element.

Particularly preferably, in the motor vehicle transmission according to the invention, in addition to switching the different gears, a neutral switching can also be implemented by not an actuated state is represented by one of the at least functionally provided switching elements. This allows the shaft to rotate freely and thus also decouples the drive shaft from the output shaft. This advantageously enables the at least one drive machine connected to the drive shaft to be decoupled.

According to one embodiment, the first switching element and the second switching element are formed by a common switching device which has a coupling element. The coupling element can be positioned in a first switching position and in a second switching position, wherein the coupling element in the first switching position functionally represents an actuated state of the first switching element and connects the third element of the second planetary gear set to the shaft in a rotationally fixed manner. In the second switching position, the coupling element functionally represents an actuated state of the second switching element and connects the third element of the first planetary gear set and the first element of the second planetary gear set to the shaft in a rotationally fixed manner. In this case, the function of the first switching element and the second switching element is represented by a switching device, which enables a particularly compact arrangement. In addition, an actuating mechanism can be provided for actuating the two switching elements, via which the coupling element can be positioned in the different switching positions. In this case, however, the transmission according to the invention can no longer engage the next gear, for the representation of which simultaneously actuated states of the first switching element and the second switching element are to be realized. Preferably, the coupling element can still be positioned in a neutral position between the switching positions, in which neither of the actuated states of the first switching element and the second switching element are represented.

In a further development of the aforementioned embodiment, the coupling element of the switching device is guided in a rotationally fixed manner and axially displaceable between the two switching positions on a first toothing which is rotationally fixedly connected to the shaft. In the first switching position, the coupling element of the switching device engages in a second toothing which is rotationally fixedly connected to the third element of the second planetary gear set. In contrast, in the second switching position, the coupling element of the switching device comes into mesh with a third toothing which is rotationally fixedly connected to the third element of the first planetary gear set and the first element of the second planetary gear set. In particular, the coupling element of the switching device is designed as a sliding sleeve, with the toothings preferably being designed as claw toothings, so that the function of unsynchronized claw switching elements is reproduced via the switching device. Within the scope of the invention, the first switching element and the second switching element could also be in the form of individual switching elements, with the two switching elements in this case being designed in particular as positive-locking switching elements and particularly preferably as unsynchronized claw switching elements. Alternatively, however, a design as locking synchronizations or as non-positive switching elements is also possible, in particular as multi-disk switching elements.

Alternatively, but preferably in addition to the aforementioned embodiment, it is a possible embodiment of the invention that the third switching element and the fourth switching element are formed by a common switching device which has a coupling element. The coupling element can be positioned in a first switching position and in a second switching position, wherein the coupling element in the first switching position functionally represents an actuated state of the third switching element and connects the second element of the first planetary gear set and the first element of the third planetary gear set to the shaft in a rotationally fixed manner. In contrast, the coupling element in the second switching position functionally represents an actuated state of the fourth switching element and connects the shaft to the output shaft in a rotationally fixed manner. This allows the function of the third switching element and the fourth switching element to be represented by a switching device and thus in a compact manner. To represent the actuated states, only one common actuating mechanism is required, via which the coupling element can be positioned in the different switching positions. Preferably, the coupling element can still be positioned in a neutral position between the switching positions, in which none of the actuated states of the third switching element and the fourth switching element are shown.

In a further development of the aforementioned design option, the switching device is designed in particular such that the coupling element of the switching device is guided in a rotationally fixed manner and can be moved axially between the two switching positions on a first toothing which is rotationally fixedly connected to the shaft. In the first switching position, the coupling element then engages in a second toothing which is rotationally fixedly connected to the second element of the first planetary gear set and the first element of the third planetary gear set. When transferred to the second switching position, the coupling element comes into contact with a third toothing Tooth engagement, which is connected to the output shaft in a rotationally fixed manner. In this case, the coupling element of the switching device is designed in particular as a sliding sleeve, with the teeth preferably being designed as claw teeth, so that the function of unsynchronized claw switching elements is reproduced via the switching device. Alternatively, the third switching element and the fourth switching element could also be present as individual switching elements, with the two switching elements in this case being designed in particular as positive switching elements and particularly preferably as unsynchronized claw switching elements. Further alternatively, individual switching elements could also be designed as locking synchronizations or as non-positive switching elements, in particular in the form of multi-disk switching elements.

Preferably, the switching device forming the third switching element and the fourth switching element is arranged axially at least overlapping the third planetary gear set and is placed radially surrounding the third planetary gear set. This makes it possible to reduce the axial length of the motor vehicle transmission according to the invention.

In the motor vehicle transmission according to the invention, both a switching device forming the first switching element and the second switching element and a switching device forming the third switching element and the fourth switching element are particularly preferably implemented. Each switching device can be assigned its own actuating mechanism or a switching drum can be provided in order to actuate the coupling elements of the switching devices.

According to one embodiment of the invention, the output shaft is coupled to a differential gear set, which couples the output shaft to two 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. The differential gear set can, however, also have the function of a longitudinal differential, via which a drive power can be distributed to several drive axles. In addition, the differential gear set can also be designed as a planetary gear differential, a spur gear differential, etc. within the scope of the invention.

In particular, the output shaft is coupled to an input element, which 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. A bevel drive of this type is also preferably used when the differential gear set is used as a longitudinal differential and the motor vehicle transmission is aligned transversely to the direction of travel.

According to one embodiment of the invention, the planetary gear sets are arranged on a connection point of the drive shaft, which serves to couple the drive shaft to the drive machine, in a sequence of first planetary gear set, second planetary gear set and third planetary gear set. This makes it possible to achieve a suitable structure of the motor vehicle transmission according to the invention. If the first shifting element and the second shifting element of the motor vehicle transmission are combined to form a shifting device, this shifting device is provided axially between the second planetary gear set and the third planetary gear set, wherein the shifting device is also arranged in particular radially surrounding the second planetary gear set and the third planetary gear set. If the third shifting element and the fourth shifting element are combined to form a shifting device, this shifting device can, as already described above, be arranged axially at least overlapping the third planetary gear set and placed radially surrounding the third planetary gear set. Alternatively, the shifting device forming the third shifting element and the fourth shifting element can also be provided axially between the second planetary gear set and the third planetary gear set. In this case, the switching device is then further arranged in particular radially surrounding the second planetary gear set and the third planetary gear set.

Within the scope of the invention, it would also be conceivable in principle to place the first planetary gear set axially at least overlapping the second planetary gear set and to arrange it radially inside the second planetary gear set. “Axially at least overlapping” means that at least a part of the first planetary gear set is axially in a plane with at least a part of the second planetary gear set. Preferably, the first planetary gear set and the second planetary gear set then overlap axially predominantly or even completely, whereby the first planetary gear set and the second planetary gear set are placed axially in a common plane. In combination with the radially inner arrangement of the first planetary gear set, this makes it possible to create a nested arrangement of the two planetary gear sets and thus achieve an axially short design. Preferably, the first planetary gear set and the second planetary gear set are then arranged axially between a connection point of the drive shaft, which serves to couple the drive shaft to the at least one drive machine, and the third planetary gear set. Alternatively or additionally, the third element of the first planetary gear set and the first element of the second planetary gear set could also be designed as one piece.

The invention also relates to a drive unit which, in addition to an electric machine, has 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 on the one hand and as an electric motor on the other. This makes it possible to create a drive unit which is suitable for use in a motor vehicle in the form of an electric or hybrid vehicle.

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 to 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 that the rotor of the electric machine is 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 to the drive shaft is also possible.

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 an electric or hybrid vehicle. The motor vehicle transmission preferably has a differential gear set which is coupled to the output shaft and couples the output shaft to output shafts. Each of the output shafts is assigned to a drive wheel of the motor vehicle drive axle.

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

• 1 eine schematische Ansicht einer Antriebseinheit gemäß einer Ausführungsform der Erfindung;
• 2 eine schematische Darstellung einer Antriebseinheit gemäß einer weiteren Ausgestaltungsmöglichkeit der Erfindung;
• 3 ein beispielhaftes Schaltschema eines Kraftfahrzeuggetriebes der Antriebseinheit aus 1 oder 2; und
• 4 eine schematische Ansicht eines Elektrofahrzeugs entsprechend einer bevorzugten Ausführungsform der Erfindung.

An advantageous embodiment of the invention, which is explained below, is shown in the drawings. It shows:

• 1 a schematic view of a drive unit according to an embodiment of the invention;
• 2 a schematic representation of a drive unit according to a further embodiment of the invention;
• 3 an exemplary circuit diagram of a motor vehicle transmission of the drive unit from 1 or 2 ; and
• 4 a schematic view of an electric vehicle according to a preferred embodiment of the invention.

Out of 1 shows a schematic view of a drive unit 1, which is designed according to an embodiment of the invention. This drive unit 1 is composed of an electric machine 2 and a motor vehicle transmission 3, which is designed according to a 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 as a generator on the one hand and as an electric motor on the other.

In addition to a drive shaft 6 and an output shaft 7, the motor vehicle transmission 3 has three planetary gear sets P1, P2 and P3, each of which is composed of a first element E11 or E12 or E13, a second element E21 or E22 or E23 and a third element E31 or E32 or E33. The respective first element E11 or E12 or E13 of the respective planetary gear set P1 or P2 or P3 is a respective sun gear, while the respective second element E21 or E22 or E23 of the respective planetary gear set P1 or P2 or P3 is designed as a respective planet carrier. In addition, the respective third element E31 or E32 or E33 of the respective planetary gear set P1 or P2 or P3 is a respective ring gear of the respective planetary gear set P1 or P2 or P3.

In the respective planet carrier of the respective planetary gear set P1 or P2 or P3, at least one planetary gear is rotatably mounted, which meshes with both the respective sun gear and the respective ring gear of the respective planetary gear set P1 or P2 or P3. In this respect, the planetary gear sets P1, P2 and P3 are designed as minus planetary sets. Within the scope of the invention, however, a design of one or more of the planetary gear sets P1 to P3 as a plus planetary set is also possible, for which, in comparison to the respective design as a minus planetary set, the respective second element E21 or E22 or E23 is to be formed by the respective ring gear and the respective third element E31 or E32 or E33 is to be formed by the respective planet carrier. Furthermore, a stationary transmission 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 planet carrier, of which one planetary gear meshes with the respective sun gear and one planetary gear meshes with the respective ring gear. In addition, the planetary gears of the at least one pair of planetary gears mesh with one another.

In the present case, the first element E11 of the first planetary gear set P1 is connected in a rotationally fixed manner to the drive shaft 6, which is also connected in a rotationally fixed manner to the rotor 5 of the electric machine 2. In this respect, the first element E11 of the first planetary gear set P1 and the rotor 5 are also connected in a rotationally fixed manner to one another via the drive shaft 6, whereby the first element E11 and the rotor 5 always rotate at the same speed. Within the scope of the invention, the drive shaft 6 can be designed as one piece with the rotor 5 of the electric machine 2 and/or with the first element E11 of the first planetary gear set P1.

The second element E21 of the first planetary gear set P1 is permanently connected in a rotationally fixed manner to the first element E13 of the third planetary gear set P3, so that these two elements E21 and E13 also constantly run at the same speed. This connection is made via a shaft 8, whereby the shaft 8 could be designed as a single piece with the second element E21 of the first planetary gear set P1 and/or with the first element E13 of the third planetary gear set P3.

Furthermore, the third element E31 of the first planetary gear set P1 and the first element E12 of the second planetary gear set P2 are constantly connected to one another in a rotationally fixed manner, wherein the rotationally fixed connection is realized via a shaft 9, which could be formed integrally with the third element E31 of the first planetary gear set P1 and/or with the first element E12 of the second planetary gear set P2.

As also in 1 As can be seen, the second element E22 of the second planetary gear set P2 is fixed to a permanently fixed component 10 and is thus permanently prevented from rotating. The fixed component 10 is preferably a transmission housing of the motor vehicle transmission 3, a part of such a transmission housing or a component connected thereto in a rotationally fixed manner. The third element E33 of the third planetary gear set P3 is also permanently fixed to the fixed component 10, as a result of which the third element E33 is also permanently prevented from rotating. The second element E23 of the third planetary gear set P3, on the other hand, is connected in a rotationally fixed manner to the output shaft 7 of the motor vehicle transmission 3, as a result of which the second element E23 of the third planetary gear set P3 permanently rotates together with the output shaft 7. The second element E23 of the third planetary gear set P3 and the output shaft 7 could also be designed as a single piece. The third element E32 of the second planetary gear set P2 is connected in a rotationally fixed manner to a shaft 11, which can be present as a radial shaft piece and can be designed as one piece with the third element E32 of the second planetary gear set P2. A shaft 12 is also provided.

In addition to the second element E23 of the third planetary gear set P3, the output shaft 7 is also permanently connected in a rotationally fixed manner to a differential cage 13 of a differential gear set 14. This differential gear set 14 is designed as a bevel gear differential, which divides a drive torque introduced into the differential cage 13 via the output shaft 7 between two output shafts 15 and 16 in a manner known in principle to those skilled in the art. The differential gear set 14 enables speed differences between the output shafts 15 and 16.

Furthermore, the motor vehicle transmission 3 has two switching devices 17 and 18. The switching device 17 has a coupling element 19 in the form of a sliding sleeve, which is guided in a rotationally fixed and axially displaceable manner on a toothing 20 which is designed on the shaft 12. Axial displacements of the coupling element 17 on the toothing 20 of the shaft 12 can be carried out via a positioning actuator - not shown here - which is preferably designed as an electromechanical positioning actuator.

The coupling element 19 can be moved via the actuator between two different switching positions, in each of which a tooth engagement of the coupling element 19 is carried out in an associated toothing 21 or 22. The toothing 21 is connected in a rotationally fixed manner to the shaft 11 and thus also to the third element E32 of the second planetary gear set P2, while the toothing 22 is connected in a rotationally fixed manner to the shaft 9 and is thus also connected in a rotationally fixed manner to the third element E3 1 of the first planetary gear set P1 and the first element E1 2 of the second planetary gear set P2.

The switching device 17 represents the function of two switching elements A and B, the respective actuated state of which is represented by the switching device 17 in each of its switching states. An actuated state of the switching element A is thus realized in a first switching position of the coupling element 17, in which the coupling element 19 engages in the toothing 21 and thus connects the shaft 11 to the shaft 12 in a rotationally fixed manner. This accordingly also results in a rotationally fixed connection of the third element E32 of the second planetary gear set P2 to the shaft 12.

From the first switching position, the coupling element 19 can be moved via the actuator into a neutral position in which the shaft 12 is not coupled via the coupling element 19. In addition to transferring the coupling element 19 into the first switching position, the coupling element 19 can also be moved from the neutral position into a second switching position in which the coupling element 19 meshes with the teeth 22 and the actuated state of the switching element B is shown. The coupling element 19 thereby connects the shaft 12 in a rotationally fixed manner to the shaft 9 and thus also to the third element E31 of the first planetary gear set P1 and the first element E12 of the second planetary gear set P2.

The switching device 18 reproduces the function of two further switching elements C and D and has a coupling element 23, which is also designed as a shift sleeve. The coupling element 23 is also guided on the shaft 12 in a rotationally fixed and axially displaceable manner, for which purpose an associated toothing 24 is formed on the side of the shaft 12. The coupling element 23 can be positioned in a first switching position, in a second switching position and in an intermediate neutral position via an actuator (not shown here), with the coupling element in the first switching position engaging in a toothing 25 which is connected in a rotationally fixed manner to the shaft 8. This has the result that the shaft 12 is connected in a rotationally fixed manner to the shaft 8 via the coupling element 23 and thus also to the second element E21 of the first planetary gear set P1 and the first element E13 of the third planetary gear set P3. This corresponds to an actuated state of the switching element C.

If the coupling element 23 is transferred from the first switching position to the intermediate neutral position, the shaft 12 is not coupled via the coupling element 23 of the switching device 18. From the neutral position, the coupling element 23 can be transferred back to the first switching position and also moved to the second switching position in which the coupling element 23 comes into mesh with a toothing 26 which is connected in a rotationally fixed manner to the output shaft 7. Accordingly, in the second switching position of the coupling element 23, the shaft 12 is connected in a rotationally fixed manner to the output shaft 7, which corresponds to an actuated state of the switching element D.

In the present case, the electric machine 2 is placed coaxially to the motor vehicle transmission 3, in which the drive shaft 6, the planetary gear sets P1 to P3, the output shaft 7, the output shafts 15 and 16, the differential gear set 14 and also the shafts 8, 9, 11 and 12 are arranged coaxially to one another. Following the axial connection of the drive shaft 6 to the rotor 5 of the electric machine 2, the planetary gear sets P1 to P3 are then arranged in the order of first planetary gear set P1, second planetary gear set P2 and finally third planetary gear set P3. The two switching devices 17 and 18 are placed axially between the second planetary gear set P2 and the third planetary gear set P3, with the switching devices 17 and 18 preferably being arranged radially surrounding the second planetary gear set P2 and the third planetary gear set P3.

Furthermore, 2 a schematic representation of a drive unit 27, which is designed according to a further embodiment of the invention and essentially corresponds to the drive unit 1 of 1 However, the difference is that in a motor vehicle transmission 28 of the drive unit 27, the switching device 18 is now arranged axially overlapping the third planetary gear set P3 and the differential gear set 14, with the switching device 18 being placed radially surrounding the third planetary gear set P3 and the differential gear set 14. As a result, the axial length of the motor vehicle transmission 28 can be reduced compared to the motor vehicle transmission 3 from 1 Otherwise, the drive unit 22 corresponds to the drive unit 1 from 1 , so that reference is made to what has been described here.

Out of 3 An example of a shifting diagram of the motor vehicle transmissions 3 and 28 is given in the 1 and 2 In this context, 3 It can be seen that in both motor vehicle transmissions 3 and 28, a first gear G1, a second gear G2, a third gear G3 and a fourth gear G4 can be engaged, whereby in the table 3 each of which is marked with an X, which actuated states of the switching elements A, B, C and D are to be represented by the switching devices 17 and 18. The first gear G1 between the drive shaft 6 and the output shaft 7 is produced by the switching device 17 showing the actuated state of the switching element A and, at the same time, the actuated state of the switching element C is represented by the switching device 18.

In contrast, for shifting the second gear G2, the actuated state of the shift element D is to be represented in the shifting device 18, while the actuated state of the shift element A is still realized in the shifting device 17. To represent the third gear G3, the actuated state of the shift element D is maintained in the shifting device 18, while the shifting device 17 changes from an actuated state of the shift element A to an actuated state of the shift element B. In principle, the fourth gear G4 can also be represented in the two motor vehicle transmissions 3 and 28, for which purpose the actuated state of the shift element B is still represented in the shifting device 17 and the actuated state of the shift element C is now represented in the shifting device 18.

Accordingly, for successive shifting of gears G1 to G4, a switchover between the two associated shift positions must be carried out in one of the shifting devices 17 and 18. Synchronization of speeds is particularly preferably supported by the electric machine 2. In addition, in the case of motor vehicle transmissions 3 and 28, the neutral positions can also be represented in both shifting devices 17 and 18, whereby the electric machine 2 is decoupled from the output shaft 7 within the respective drive unit 1 or 27.

If, in addition, the functions of the two shifting elements A and B are not represented by a common shifting device, a further gear can also be engaged in a suitably designed motor vehicle transmission by simultaneously operating the shifting element A and the shifting element B. In terms of its transmission ratio, this further gear lies between the second gear G2 and the third gear G3.

Finally, 4 a schematic view of an electric vehicle 29, which can in particular be an electric commercial vehicle, such as a transporter. 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 a drive unit 34, which in this case corresponds to one of the variants according to the 1 and 2 The drive wheel 32 is connected in a rotationally fixed manner to the output shaft 15 of the drive unit 34, while the drive wheel 33 is connected in a rotationally fixed manner to the output shaft 16 of the drive unit 34.

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, as an alternative or in addition to the motor vehicle drive axle 31, the vehicle axle 30 could also be designed as a driven axle with, if necessary, an analogous structure of a drive unit.

By means of the design according to the invention, a compact motor vehicle transmission with a suitable gear ratio for the integration of an electric machine can be realized.

reference sign

1

drive unit

2

electric machine

3

automotive transmissions

4

stator

5

rotor

6

drive shaft

7

output shaft

8

Wave

9

Wave

10

fixed component

11

Wave

12

Wave

13

differential cage

14

differential gear set

15

output shaft

16

output shaft

17

switching device

18

switching device

19

coupling element

20

gearing

21

gearing

22

gearing

23

coupling element

24

gearing

25

gearing

26

gearing

27

drive unit

28

automotive transmissions

29

electric vehicle

30

vehicle axle

31

motor vehicle drive axle

32

drive wheel

33

drive wheel

34

drive unit

P1

First planetary gear set

P2

second planetary gear set

P3

third 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 of the second planetary gear set

E22

Second element second planetary gear set

E32

Third element second planetary gear set

E13

First element of the third planetary gear set

E23

Second element third planetary gear set

E33

Third element third planetary gear set

A

switching element

B

switching element

C

switching element

D

switching element

G1

first course

G2

second gear

G3

third gear

G4

fourth gear

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The 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

• DE 102017006262 A1 [0003]

Claims (17)

Motor vehicle transmission (3; 28) for an at least partially electrically driven motor vehicle, in particular for an electrically drivable motor vehicle drive axle (31), comprising a drive shaft (6), an output shaft (7) and a first planetary gear set (P1), a second planetary gear set (P2) and a third planetary gear set (P3), wherein the drive shaft (6) is provided for coupling to at least one drive machine, wherein the first planetary gear set (P1), the second planetary gear set (P2) and the third planetary gear set (P3) each have a first element (E11, E12, E13), a second element (E21, E22, E23) and a third element (E31, E32, E33) in the form of a sun gear, a planet carrier and a ring gear, wherein at least functionally a first switching element (A), a second switching element (B) and a third switching element (C) are provided, and wherein the first element (E11) of the first Planetary gear set (P1) is connected to the drive shaft (6) in a rotationally fixed manner, characterized in that - the second element (E21) of the first planetary gear set (P1) and the first element (E13) of the third planetary gear set (P3) are connected to one another in a rotationally fixed manner, - the third element (E31) of the first planetary gear set (P1) and the first element (E12) of the second planetary gear set (P2) are connected to one another in a rotationally fixed manner, - the second element (E22) of the second planetary gear set (P2) is fixed, - the third element (E33) of the third planetary gear set (P3) is fixed, - the second element (E23) of the third planetary gear set (P3) is connected to the output shaft (7) in a rotationally fixed manner, - the third element (E32) of the second planetary gear set (P2) is connected to a shaft in a rotationally fixed manner in the actuated state of the at least functionally provided first switching element (A) (12) which, in the actuated state of the at least functionally provided second switching element (B), is connected in a rotationally fixed manner to the third element (E31) of the first planetary gear set (P1) and the first element (E12) of the second planetary gear set (P2), - that the shaft (12) in the actuated state of the at least functionally provided third switching element (C) is connected in a rotationally fixed manner to the second element (E21) of the first planetary gear set (P1) and the first element (E13) of the third planetary gear set, - and that in addition, at least functionally, a fourth switching element (D) is provided, in the actuated state of which the shaft (12) is connected in a rotationally fixed manner to the output shaft (7). Motor vehicle transmission (3; 28) according to claim 1 , characterized in that the first switching element (A) and the second switching element (B) are formed by a common switching device (17) which has a coupling element (19), wherein the coupling element (19) can be positioned in a first switching position and in a second switching position, wherein the coupling element (19) in the first switching position functionally represents an actuated state of the first switching element (A) and connects the third element (E32) of the second planetary gear set (P2) to the shaft (12) in a rotationally fixed manner, and wherein the coupling element (19) in the second switching position functionally represents an actuated state of the second switching element (B) and connects the third element (E31) of the first planetary gear set (P1) and the first element (E12) of the second planetary gear set (P2) to the shaft (12) in a rotationally fixed manner. Motor vehicle transmission (3; 28) according to claim 2 , characterized in that the coupling element (19) of the switching device (17) is guided in a rotationally fixed manner and axially displaceable between the two switching positions on a first toothing (20) which is rotationally fixedly connected to the shaft (12), wherein the coupling element (19) of the switching device (17) in the first switching position engages in a second toothing (21) which is rotationally fixedly connected to the third element (E32) of the second planetary gear set (P2), whereas the coupling element (19) of the switching device (17) in the second switching position comes into tooth engagement with a third toothing (22) which is rotationally fixedly connected to the third element (E31) of the first planetary gear set (P1) and the first element (E12) of the second planetary gear set (P2). Motor vehicle transmission (3; 28) according to one of the Claims 1 until 3 , characterized in that the third switching element (C) and the fourth switching element (D) are formed by a common switching device (18) which has a coupling element (23), wherein the coupling element (23) can be positioned in a first switching position and in a second switching position, wherein the coupling element (23) in the first switching position functionally represents an actuated state of the third switching element (C) and connects the second element (E21) of the first planetary gear set (P1) and the first element (E13) of the third planetary gear set to the shaft (12) in a rotationally fixed manner, and wherein the coupling element (23) in the second switching position functionally represents an actuated state of the fourth switching element (D) and connects the shaft (12) to the output shaft (7) in a rotationally fixed manner. Motor vehicle transmission (3; 28) according to claim 4 , characterized in that the coupling element (23) of the switching device (18) is rotationally fixed and is guided axially displaceably between the two switching positions on a first toothing (24) which is connected in a rotationally fixed manner to the shaft (12), wherein the coupling element (23) of the switching device (18) in the first switching position engages in a second toothing (25) which is connected in a rotationally fixed manner to the second element (E21) of the first planetary gear set (P1) and the first element (E13) of the third planetary gear set, whereas the coupling element (23) of the switching device (18) in the second switching position comes into tooth engagement with a third toothing (26) which is connected in a rotationally fixed manner to the output shaft (7). Motor vehicle transmission (28) according to claim 4 or 5 , characterized in that the switching device (18) forming the third switching element (C) and the fourth switching element (D) is arranged axially at least overlapping with the third planetary gear set (P3) and is placed radially surrounding the third planetary gear set (P3). Motor vehicle transmission (3; 28) according to one of the preceding claims, characterized in that the output shaft (7) is coupled to a differential gear set (14) which couples the output shaft (7) to two output shafts (15, 16). Motor vehicle transmission (3; 28) according to one of the preceding claims, characterized in that the planetary gear sets (P1, P2, P3) are arranged on a connection point of the drive shaft (6), which serves to couple the drive shaft (6) to the drive engine, in a sequence of first planetary gear set (P1), second planetary gear set (P2) and third planetary gear set (P3). Motor vehicle transmission (3; 28) according to claim 8 and after claim 2 or 3 , characterized in that the switching device (17) forming the first switching element (A) and the second switching element (B) is provided axially between the second planetary gear set (P2) and the third planetary gear set (P3). Motor vehicle transmission (3) according to claim 8 or 9 and after one of the Claims 4 until 6 , characterized in that the switching device (18) forming the third switching element (C) and the fourth switching element (D) is provided axially between the second planetary gear set (P2) and the third planetary gear set (P3). Drive unit (1; 27; 34) for an at least partially electrically driven motor vehicle, comprising an electric machine (2) and a motor vehicle transmission (3; 28) according to one or more of the Claims 1 until 10 , wherein a rotor (5) of the electric machine (2) is coupled to the drive shaft (6) of the motor vehicle transmission (3; 28). Drive unit (1; 27; 34) according to claim 11 , characterized in 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. Electrically driven motor vehicle drive axle (31) for an at least partially electrically driven motor vehicle, comprising a drive unit (1; 27; 34) according to claim 11 or 12 . Hybrid or electric vehicle (29), comprising a drive unit (34) according to claim 11 or 12 or a motor vehicle drive axle (31) according to claim 13 . Method for operating a motor vehicle transmission (3; 28) according to one or more of the Claims 1 until 10 , - wherein a first gear (G1) is switched between the drive shaft (6) and the output shaft (7) by simultaneously displaying operated states of the first switching element (A) and the third switching element (C), - wherein a second gear (G2) is switched between the drive shaft (6) and the output shaft (7) by simultaneously displaying operated states of the first switching element (A) and the fourth switching element (D), - and wherein a third gear (G3) is switched between the drive shaft (6) and the output shaft (7) by simultaneously displaying operated states of the second switching element (B) and the fourth switching element (D). procedure according to claim 15 , characterized in that an additional gear (G4) is switched between the drive shaft (6) and the output shaft (7) by simultaneously representing actuated states of the second switching element (B) and the third switching element (C). procedure according to claim 15 or 16 , characterized in that a further gear is switched between the drive shaft and the output shaft by simultaneously representing actuated states of the first switching element and the second switching element.

Images