Transmission for a motor vehicle, as well as drivetrain and motor vehicle with such a transmission

Abstract

Transmission (200, 300) for a motor vehicle with a drive device (2), comprising: a first input wave (10.1), a second input wave (10.2), at least one gear set (15.1, 15.2, 15.3, 15.4, 15.5) for forming at least one gear stage (V1, V2, V3, V4, E1.1, E1.2, E1.3, E2.1, E2.2, E2.3, E2.4), at least one countershaft (13.1, 13.2) for a rotationally fixed connection of the gearbox (200, 300) with an output shaft, wherein a first electrical machine (11) is connected to the first input shaft (10.1) in a rotationally fixed manner or can be detachably and rotationally fixedly connected via a switching element, wherein the drive device (2) is connected to the second input shaft (10.2) in a rotationally fixed manner or can be detachably and rotationally fixedly connected via a switching element (17.1), wherein a second electric machine (12) is connected to the second input shaft (10.2) in a rotationally fixed manner or can be detachably and rotationally fixedly connected via a switching element, wherein the first electric machine (11) and the second electric machine (12) are arranged overlapping and coaxially in the axial direction, characterized in that at least one loose gear is provided which can be detachably and non-rotatably connected to the first input shaft (10.1) and which meshes with at least one fixed gear which is non-rotatably connected to the countershaft (13.1, 13.2) or at least one fixed gear (14.1) which is non-rotatably connected to the first input shaft (10.1) and which meshes with at least one loose gear (16.1, 16.5) which can be detachably and non-rotatably connected to the countershaft (13.1, 13.2), each to form at least one gear set (15.1, 15.5), wherein at least one switching element (17.2, 17.6) is provided for connecting the first input shaft (10.1) or the countershaft (13.1, 13.2) to the at least one loose gear (16.1, 16.5), and / or wherein at least one loose gear (16.4) is provided which can be detachably and non-rotatably connected to the second input shaft (10.2) and which meshes with at least one fixed gear (14.3) which is non-rotatably connected to the countershaft (13.1, 13.2) or at least one fixed gear (14.2) which is non-rotatably connected to the second input shaft (10.2) and which meshes with at least one loose gear (16.2, 16.3) which can be detachably and non-rotatably connected to the countershaft (13.1, 13.2), each to form at least one gear set (15.2, 15.3, 15.4), wherein at least one switching element (17.3, 17.4, 17.5) is provided for connecting the second input shaft (10.2) or a countershaft (13.1, 13.2) to the at least one loose gear (16.2, 16.3, 16.4).

Description

[0001] The invention relates to a transmission for a motor vehicle with two input shafts and two electric motors. Furthermore, the invention relates to a drive train for a motor vehicle with such a transmission and a motor vehicle with such a drive train.

[0002] Transmissions of this type are known from the prior art. Transmissions are known, particularly for hybrid vehicles, which, in addition to gear sets, also have several, in particular precisely two, electric motors. The transmission is typically designed with multiple gears, i.e., several different gear ratios can be switched between one or more input shafts and an output shaft by actuating corresponding shifting elements and the associated selection of corresponding gear sets, with this preferably occurring automatically. Gear ratios of the transmission are also usually used in conjunction with the electric motors to enable purely electric driving.In the same and / or further gear stages, driving operation with a drive device, which is for example an internal combustion engine, is usually provided and / or driving operation in which the drive device and one or both electric machines serve together to drive the vehicle.

[0003] A disadvantage of transmissions with multiple electric machines is that they require a lot of installation space. Arrangements are known in which the multiple electric machines are arranged coaxially and one behind the other in the axial direction, so that such transmissions are protruding in the axial direction and are therefore not or hardly suitable for transverse installation in a motor vehicle. Arrangements are also known in which the electric machines are arranged axially parallel to one another. For example, a first electric machine is then arranged coaxially with the input shafts and a second electric machine on a parallel axis. A disadvantage of such transmissions is that they are very large in the radial direction and are therefore not or hardly suitable for longitudinal installation in a motor vehicle. This is even more true if the transmission has one or more countershafts, which make additional use of the radial installation space.

[0004] For example, DE 10 2019 216 213 A1 discloses a transmission with a first input shaft and a second input shaft, as well as a countershaft and multiple gear ratios, in which a drive device can be selectively connected to one of the input shafts via a shift element. A first electric motor arranged on a first parallel axis acts on the first input shaft. A second electric motor arranged on a second parallel axis acts on the second input shaft. The disadvantage of this transmission is that it requires a lot of installation space, particularly in the radial direction.

[0005] Furthermore, DE 11 2010 003 828 T5, WO 2011 / 054 097 A1, DE 10 2020 108 232 A1 and DE 103 14 234 B3 also disclose generic transmissions for motor vehicles.

[0006] Based on the described prior art, it is an object of the invention to provide an alternative compact transmission for a motor vehicle with which different functions can be represented in a suitable manner.

[0007] This object is achieved according to a first aspect of the invention with a transmission having the features of claim 1. The subsequent dependent claims each provide advantageous developments of the first aspect of the invention. A drive train for a motor vehicle according to a second aspect of the invention is the subject of claim 12. A motor vehicle according to a third aspect of the invention is also the subject of claim 13.

[0008] According to the first aspect of the invention, the transmission comprises a first input wave, a second input shaft, at least one gear set for forming at least one gear stage, wherein a first electric machine is connected to the first input shaft in a rotationally fixed manner or is detachably and rotationally fixedly connectable via a switching element, wherein the drive device is connected to the second input shaft in a rotationally fixed manner or is detachably and rotationally fixedly connectable via a switching element, wherein a second electric machine is connected to the second input shaft in a rotationally fixed manner or is detachably and rotationally fixedly connectable via a switching element, and wherein the first electric machine and the second electric machine are arranged overlapping one another and coaxially in the axial direction.

[0009] To the extent that elements are designated by numbering, for example, "first component," "second component," and "third component," this numbering is intended purely for differentiation in the designation and does not represent a dependency of the elements on one another or a mandatory sequence of the elements. This means, in particular, that a device does not have to have a "first component" in order to have a "second component." The device may also comprise a "first component" and a "third component," but without necessarily having a "second component."

[0010] A drive device is understood to be a device that provides a mechanical torque and a rotational speed to a shaft. Drive devices are, in particular, internal combustion engines or electric machines. While the following exemplary embodiments assume a drive device to be an internal combustion engine, this does not preclude the possibility that the drive device may be designed differently in a corresponding embodiment.

[0011] For the purposes of the invention, a shaft is understood to be a rotatable component of the transmission for transmitting torque, via which associated components of the transmission are connected to one another in a rotationally fixed manner or via which such a connection is established when a corresponding switching element is actuated. The respective shaft can connect components of the transmission axially or radially, or even both axially and radially. The respective shaft can also be in the form of an intermediate piece via which a respective component is connected radially, for example. In addition, the respective shaft can be designed as a single-piece component or in multiple parts, with the respective shaft being composed of several shaft parts connected to one another in a rotationally fixed manner.

[0012] A gear set is understood to be a combination of gears, in particular a spur gear pair consisting of a fixed gear and an idler gear, or two fixed gears, or a planetary gear set consisting of at least three elements. A gear set connects a transmission input shaft to an output shaft at a defined gear ratio, with the drive power being transmitted from the drive device to the output shaft at this gear ratio. In particular, a gear set is intended to provide a gear ratio in a load path of a gear stage.

[0013] If a switching element is provided between two components, these components are not permanently connected to one another; rather, a connection is only established when the switching element is actuated. Actuation of the switching element within the meaning of the invention means that the switching element in question is transferred to a closed state and, as a result, the components directly connected to it may align their rotational movements. If the switching element in question is designed as a form-locking switching element, the components directly connected to one another in a rotationally fixed manner will run at the same speed, whereas in the case of a force-locking switching element, speed differences can exist between the components even after the switching element has been actuated.This intended or unwanted state is nevertheless referred to in the context of the invention as a rotationally fixed connection of the respective components via the switching element.

[0014] A gear ratio is defined as the sum of the shift positions of all shift elements in the transmission, resulting in a total gear ratio as the product of all individual gear ratios. In a gear ratio, the drive power is transferred between the input and output via a load path, i.e., a specific sequence of transmission components.

[0015] A non-rotatable connection is defined as a connection between two torque-carrying parts that allows drive power to be transferred between them. In particular, both parts are appropriately supported. Non-rotatable connections include both those that have no transmission or intermediate components, as well as those that do have transmission or intermediate components.

[0016] A detachable connection is one that can be opened non-destructively after it has been established, particularly in such a way that the connection can be opened and closed repeatedly. Preferably, the connection can be switched between a defined closed and a defined open state at will.

[0017] For the purposes of the invention, "axial" refers to an orientation along a longitudinal center axis of the transmission, parallel to which the rotational axes of the input shafts and the countershaft are arranged. "Radial" refers to an orientation along the diameter of this longitudinal center axis.

[0018] Overlapping means that both the first and second electrical machines extend within an axial overlap region. This means that in this overlap region, the two electrical machines do not overlap in the radial direction, i.e., they extend in different radial regions. In other words, an internal electrical machine is arranged within an external electrical machine in the overlap region and extends radially only within the clear inner diameter of the external electrical machine.

[0019] In the present case, the electrical machines are preferably each composed of a stator and a rotor, of which the stator is permanently fixed, while the rotor is mounted so as to be rotatable radially inward or outward relative to the stator. The electrical machines are part of the transmission according to the invention and are preferably integrated into a transmission housing of the transmission, with the stator more preferably being fixed to a rotationally fixed component of the transmission. The electrical machines can, in particular, be used in generator mode to generate electricity or operated in electromotive mode, in which a drive movement is generated via the electrical machines.

[0020] The first aspect of the invention encompasses the technical teaching according to which the two electrical machines overlap in the axial direction and are arranged coaxially. This means that the two electrical machines are designed such that one engages in a free interior space of the other, creating an overlapping area. One electrical machine is then arranged at least partially within the other electrical machine. In this way, the transmission is advantageously designed to be particularly compact, since the electrical machines do not have to be arranged entirely one behind the other or next to each other in either the axial or radial direction. The coaxial arrangement also achieves good mechanical efficiency.

[0021] The overlapping area extends either over a portion of one or both electrical machines, or over the entire length of the axially shorter of the two electrical machines. In particular, the outer diameter of one electrical machine is smaller than the inner diameter of the other electrical machine and is arranged within the other electrical machine.

[0022] According to a preferred embodiment, the second electric machine is completely covered in the axial direction by the first electric machine, or the first electric machine is completely covered in the axial direction by the second electric machine. This creates a particularly compact transmission.

[0023] Furthermore, the first electrical machine is preferably larger than the second electrical machine, and the second electrical machine is arranged at least partially radially inside the first electrical machine. In other words, the two electrical machines are coaxial with one another and have a common axis of rotation, with the second electrical machine being arranged at least partially or completely radially inside the rotor of the first electrical machine. Larger is understood here, on the one hand, in a geometric sense, so that the second electrical machine has smaller dimensions, in particular an outer diameter that is smaller than an internal diameter of the first electrical machine.Thus, the inner diameter of the rotor of the first electric machine is larger than the outer diameter of the stator of the second electric machine, with the second electric machine at least partially extending axially into the second electric machine, in particular completely overlapping with the second electric machine. Larger, on the other hand, also refers to a technical design. Thus, the second electric machine can, in particular, provide a lower torque. In one embodiment, the second electric machine is designed for higher maximum speeds than the first electric machine.

[0024] In an embodiment with a larger first electric machine, the first electric machine in the transmission is particularly provided for functions with greater torque requirements. For example, a gear stage for starting the motor vehicle can be provided on the first input shaft, which is carried out by means of the first electric machine, in particular without the assistance of the drive device and / or the second electric machine. The second electric machine is then particularly provided for supporting functions with lower torque requirements. For example, in hybrid gear stages, the second electric machine can drive the vehicle together with the drive device via the second input shaft.

[0025] According to the invention, the transmission has at least one countershaft for the rotationally fixed connection of the transmission to an output.

[0026] A countershaft is to be understood as a shaft which runs on a different, preferably parallel axis than the input shaft or input shafts, whereby the countershaft and input shafts can transmit a torque to each other, in particular at several points via gear sets.

[0027] The output is defined as a part of a drivetrain downstream of the transmission, by means of which the drive power, translated in the transmission, is transferred to the wheels of the vehicle. The output includes, in particular, a differential.

[0028] A transmission with a countershaft design advantageously enables a wide range of functions to be implemented in a compact size. In particular, such a transmission can be used to cost-effectively integrate a first and a second electric motor.

[0029] According to the invention, in such a transmission with a countershaft design, at least one loose gear is provided which is detachably and non-rotatably connectable to the first input shaft and meshes with at least one fixed gear which is non-rotatably connected to a countershaft, or at least one fixed gear which is non-rotatably connected to the first input shaft and meshes with at least one loose gear which is detachably and non-rotatably connectable to a countershaft, in each case to form at least one gear set, wherein at least one shifting element is provided for connecting the first input shaft or a countershaft to the at least one loose gear. Thus, at least one gear set is formed on the first input shaft for a gear stage which can be shifted via the shifting element and via which the motor vehicle can be driven, in particular by means of the first electric machine. In particular, a gear stage for starting the motor vehicle is provided on the first input shaft.Furthermore, one or more further gear sets are preferably arranged on the first input shaft to form further gear stages.

[0030] Idler gears are gears that are rotatably mounted on a shaft and can preferably be connected to this or another shaft in a rotationally fixed or detachable manner by a shifting element. Fixed gears, on the other hand, are gears that are permanently connected to a shaft in a rotationally fixed manner. In the present invention, idler gears assigned to the second input shaft are mounted, for example, on the first or second input shaft or on the countershaft. Gears that mesh or mesh with each other transmit a rotational speed and a torque via their intermeshing teeth.

[0031] Further preferably, in such a transmission with a countershaft design, at least one loose gear is provided which is detachably and non-rotatably connectable to the second input shaft and meshes with at least one fixed gear which is non-rotatably connected to a countershaft, or at least one fixed gear which is non-rotatably connected to the second input shaft and meshes with at least one loose gear which is detachably and non-rotatably connectable to a countershaft, in each case to form at least one gear set, wherein at least one shifting element is provided for connecting the second input shaft or a countershaft to the at least one loose gear. Thus, at least one gear set is formed on the second input shaft for a gear stage which can be shifted via the shifting element and via which the motor vehicle can be driven, in particular by means of the drive device and / or the second electric machine.In particular, a gear stage for driving in medium and high speed ranges is formed on the second input shaft. Furthermore, one or more additional gear sets are preferably arranged on the second input shaft to form additional gear stages.

[0032] Preferably, the ratios of the aforementioned gear stages are each selected such that a gear stage is provided on the first input shaft for starting and driving in low speed ranges, while at least one gear stage on the second input shaft forms a ratio for driving at higher speeds. In particular, several gear stages are provided, providing a series of ratios for successive speed ranges.

[0033] In an embodiment alternative to the countershaft design or in an embodiment integrated in the countershaft design, the transmission has at least one first planetary gear set for forming at least one gear stage.

[0034] A planetary gear set according to the invention comprises three different types of elements: at least one sun gear, at least one planet carrier, and at least one ring gear. Planetary gears are rotatably mounted on the planet carrier and mesh with the teeth of a sun gear and / or the teeth of a ring gear. By connecting shafts, in particular input shafts, countershafts, intermediate shafts, and / or output shafts, to individual ones of the three elements and optionally securing individual elements, gear ratios are created between the connected shafts. In particular, the connections of shafts or the securing of elements can be released using switching elements.

[0035] By integrating one or more planetary gear sets or by constructing the transmission in a pure planetary gear set design, a compact transmission is advantageously created with which a multitude of functions can be mapped.

[0036] Preferably, in the aforementioned transmission, such as a transmission with a countershaft design or a planetary gear set design, the first input shaft can be detachably and rotationally fixedly connected to the second input shaft via a sixth shift element. In this way, gear stages formed on the first input shaft can be used via the drive device and / or second electric motor connected to the second input shaft. Gear stages formed on the second input shaft can also be used via the first electric motor connected to the first input shaft.

[0037] The transmission preferably has at least one second planetary gear set for increasing the torque of one of the electric machines. In particular, such a planetary gear set is provided for the smaller or lower-torque of the two electric machines. In the preferred embodiments described above, this is in particular the second electric machine. In this way, a particularly compact electric machine can be selected that is particularly well suited to being arranged axially overlapping with the other electric machine, while at the same time, by increasing the torque in the sense of a pre-transmission, sufficient torque is made available at the input shaft, in particular at the second input shaft.

[0038] In one configuration of this embodiment, the planetary gear set has a first element, a second element, and a third element, wherein the electric machine is connected in a rotationally fixed manner to the first element, wherein the second element is connected in a rotationally fixed manner to the first or second input shaft, and wherein the third element is fixed. The third element is preferably fixed to a transmission housing of the transmission. In particular, the electric machine is connected in a rotationally fixed manner to the sun gear, while the planet carrier is connected to the input shaft, and the ring gear is fixed. The planetary gear set is arranged either axially next to the associated electric machine or overlapping them.

[0039] In one embodiment, at least two switching elements are combined to form a multiple switching device with a common actuator. Depending on the configuration, a participating switching element can be actuated via the actuator, whereby one or more neutral positions can be provided in which none of the switching elements is actuated. Combining them to form multiple switching devices has the advantage of reducing the number of actuators and thus lowering the manufacturing effort.

[0040] In one embodiment, the transmission has at least two gear stages, wherein in one gear stage the first electric machine can drive the motor vehicle via the first input shaft and in a further gear stage the drive device can drive the motor vehicle via the second input shaft. In particular, one gear stage is a gear stage for starting the motor vehicle and the further gear stage is one for operating the motor vehicle at medium to high speeds. Preferably, the transmission has further gear stages which together result in a series of gear stages by means of which the motor vehicle can be driven efficiently over a wide speed range using the drive device and the two electric machines.Furthermore, the transmission preferably has additional functions such as at least one gear stage for reversing, at least one gear stage for serial operation, at least one gear stage for charging an energy storage device by means of the drive device, at least one gear stage for driving the motor vehicle by means of the first and the second electric machine together and / or an arrangement for electrodynamic starting.

[0041] In a preferred embodiment, one of the electric machines is designed as an internal rotor and the other as an external rotor. In particular, the internal electric machine is designed as an internal rotor. This allows for a compact and simple connection of the two electric machines to the transmission housing between the two electric machines. Furthermore, the electric fields of the electric machines are thus kept as far apart as possible, thus minimizing any possible interactions.

[0042] Furthermore, the first input shaft and the second input shaft are preferably arranged coaxially. In particular, one of the input shafts is designed as a solid shaft, and the other input shaft is designed as a hollow shaft arranged to at least partially axially overlap the first input shaft. This creates a particularly compact transmission.

[0043] Particularly preferably, the second input shaft is designed as a solid shaft, and the first input shaft is designed as a hollow shaft arranged to at least partially axially overlap the second input shaft. The first input shaft can extend completely through the transmission, so that the second electric motor can engage at one axial end of the second input shaft and the drive device can engage at the opposite axial end.

[0044] The second aspect of the invention relates to a drive train for a motor vehicle with a transmission as described above. The drive train has the advantages already described with regard to the transmission.

[0045] The third aspect of the invention also relates to a motor vehicle with such a drive train, which also has the advantages already explained with regard to the transmission.

[0046] The invention is described below with reference to figures showing various embodiments of the invention, wherein identical or similar elements are provided with the same reference numerals. In detail: Fig. 1 is a schematic view of a drive train according to the second aspect of the invention in a preferred embodiment; Fig. 2 a schematic representation of a part of a drive train with a transmission according to the prior art; Fig. 3 a schematic representation of a part of the drive train from Fig. 1 with a transmission according to the first aspect of the invention in a first embodiment; Fig. 4 a schematic representation of part of the drive train from Fig. 1 with a transmission according to the first aspect of the invention in a second embodiment; and Fig. 5 a tabular representation of different functions of the gearboxes from Fig. 3 and Fig. 4.

[0047] Fig. 1 shows a schematic view of a drive train 1 for a motor vehicle, in particular for a hybrid vehicle, according to the second aspect of the invention, wherein in the drive train 1, a drive device 2 in the form of an internal combustion engine is connected to a transmission 200, 300. A differential gear 5 is connected downstream of the transmission 200, 300 on the output side, via which a drive power is distributed to drive wheels 6 and 7 of a drive axle of the motor vehicle. The transmission 200, 300 is arranged in a transmission housing 8 of the transmission 200, 300, into which the differential gear 5 can also be integrated. As also shown in Fig. 1, the drive device 2, the transmission 200, 300 and also the differential gear 5 are aligned transversely to a direction of travel of the motor vehicle.

[0048] Fig. 2 shows a schematic representation of a transmission 100 according to the prior art. The transmission 100 has a first input shaft 10.1 and a second input shaft 10.2 coaxial with the first input shaft 10.1, wherein a first electric machine 11 is connected to the first input shaft 10.1. More precisely, a rotor 11.1 of the first electric machine 11 is connected to the first input shaft 10.1, while the first electric machine also has a stator 11.2 that is fixedly arranged on the transmission housing 8. The drive device 2 and a second electric machine 12 engage the second input shaft 10.2 via a first shifting element 17.1 via a traction drive, wherein the traction drive is formed from a traction mechanism between a fifth fixed gear 14.5 on the axis of the second electric machine 12 and a second fixed gear 14.2 on the second input shaft 10.2.The second electric machine 12 is arranged axially parallel to the input shafts 10.1, 10.2.

[0049] The transmission 100 further includes a first countershaft 13.1 and a second countershaft 13.2, each connected to the output-side differential. Gear stages are formed between the input shafts 10.1, 10.2 and the countershafts 13.1, 13.2 by means of several gear sets.

[0050] Thus, a first gear set 15.1 is formed by means of a first fixed gear 14.1 arranged on the first input shaft 10.1 and a first loose gear 16.1 arranged on the first countershaft 13.1, wherein the first loose gear 16.1 can be connected to the first countershaft 13.1 by means of a second shift element 17.2 for engaging the gear stage.

[0051] A second gear set 15.2 is formed by means of the second fixed gear 14.2 arranged on the second input shaft 10.2 and a second loose gear 16.2 arranged on the first countershaft 13.1, wherein the second loose gear 16.2 can be connected to the first countershaft 13.1 by means of a third shift element 17.3 for engaging the gear stage.

[0052] A third gear set 15.3 is formed by means of the second fixed gear 14.2 arranged on the second input shaft 10.2 and a third loose gear 16.3 arranged on the second countershaft 13.2, wherein the third loose gear 16.3 can be connected to the second countershaft 13.2 by means of a fourth shift element 17.4 for engaging the gear stage.

[0053] A fourth gear set 15.4 is formed by means of a fourth idler gear 16.4 arranged on the second input shaft 10.2 and a third fixed gear 14.3 arranged on the second countershaft 13.2, wherein the fourth idler gear 16.4 can be connected to the second input shaft 10.2 by means of a fifth shift element 17.5 for engaging the gear stage.

[0054] A fifth gear set 15.5 is formed by means of the first fixed gear 14.1 arranged on the first input shaft 10.1 and a fifth loose gear 16.5 arranged on the second countershaft 13.2, wherein the fifth loose gear 16.5 can be connected to the second countershaft 13.2 by means of a sixth shift element 17.6 for engaging the gear stage.

[0055] The first input shaft 10.1 and the second input shaft 10.2 can also be connected by means of a seventh shift element 17.7. The countershafts 13.1, 13.2 are connected to the output of the differential 5 via a fourth fixed gear 14.4 on the first countershaft 13.1 and via the third fixed gear 14.3 and a traction drive connected thereto.

[0056] The fifth switching element 17.5 and the seventh switching element 17.7 are combined to form a double switching element with a common actuator. In a neutral position, either neither of the two switching elements 17.5, 17.7 can be engaged, or exactly one of the two switching elements 17.5, 17.7 can be engaged.

[0057] Fig. Figure 3 shows a transmission 200 according to the first aspect of the invention, which differs from the transmission 100 primarily in the arrangement of the electric motors 11, 12. The focus here will be primarily on the differences from the transmission 100 and, in particular, not on the gear sets 15.1, 15.2, 15.3, 15.4, 15.5.

[0058] According to the invention, the first electric machine 11 and the second electric machine 12 are arranged so as to overlap axially and form an overlap region 18 which extends over the entire length of the shorter second electric machine 12. The two electric machines 11, 12 are also arranged coaxially. The first electric machine 11 therefore completely covers the second electric machine 12. In this way, the transmission 200, in contrast to the transmission housing 100, is significantly more compact in the radial direction while maintaining the same axial length. It would also be conceivable, although not shown, for the overlap region 18 to extend only over part of the respective axial lengths of the two electric machines 11, 12, so that the electric machines 11, 12 do not overlap completely, but only partially.

[0059] The second electric machine 12 is shown here with a rotor 12.1 and a stator 12.2 fixed to the transmission housing 8. The rotor 12.1 is rotationally fixedly connected to the second input shaft 10.2.

[0060] Fig. Figure 4 shows a schematic representation of another embodiment of a transmission 300 according to the first aspect of the invention. This differs from the transmission 200 of Fig. 3 in two aspects. Here, the first electric machine 11 is designed as an external rotor, while the second electric machine is designed as an internal rotor. This allows the respective stators 11.2, 12.2 to be connected to the gear housing 8 in a particularly compact manner. The gear housing 8 can also be designed more simply.

[0061] Furthermore, the transmission 300 has a planetary gear set 19 arranged coaxially around the second input shaft 10.2. The planetary gear set 19 has a first element 19.1, a second element 19.2, and a third element 19.3, wherein the first element 19.1 is a sun gear, the second element 19.2 is a planet carrier, and the third element 19.3 is a ring gear. The second electric machine 12 is connected to the first element 19.1, with the second element 19.2 being connected to the second input shaft 10.2. The third element 19.3 is fixed to the transmission housing 8. During operation of the second electric machine 12, its torque is transmitted to the second input shaft 10.2, increased by the gear ratio of the planetary gear set 19.

[0062] Out of Fig.5, the gear ratios that can be shifted with the transmissions 100, 200, and 300 result as various transmission functions. The gear ratios shown in the functions are divided into four combustion gear ratios V1, V2, V3, and V4, three electric gear ratios E1.1, E1.2, and E1.3 for the first electric machine 11, and four electric gear ratios E2.1, E2.2, E2.3, and E2.4 for the second electric machine. However, this assignment does not preclude the possibility that, in addition to the referenced drive devices, other drive devices also act on the transmission in the respective gear ratios. For example, in all combustion gear ratios V1, V2, V3, and V4, drive by the drive device 2 and the second electric machine 12 in hybrid operation is possible. Furthermore, the naming of the combustion gear ratios V1, V2, V3, and V4 does not preclude the possibility that the drive device 2 can be something other than an internal combustion engine.

[0063] A first function I results in the first combustion gear V1 when the first shifting element 17.1, the second shifting element 17.2, and the seventh shifting element 17.7 are engaged. The drive device 2 can then drive the motor vehicle via the second input shaft 10.2, the first input shaft 10.1, the first gear set 15.1, and the first countershaft 13.1. Additionally, the second electric motor 12 on the second input shaft 10.2 or the first electric motor 11 on the first input shaft 10.1 can generate additional torque.

[0064] A second function II results in the second combustion engine gear stage V2 when the first shift element 17.1 and the third shift element 17.3 are engaged. The drive device 2 can then drive the motor vehicle via the second input shaft 10.2, the second gear set 15.2, and the first countershaft 13.1. In addition, the second electric motor 12 can apply additional torque to the second input shaft 10.2.

[0065] A third function III results in the third combustion gear stage V32 when the first shift element 17.1 and the fourth shift element 17.4 are engaged. The drive device 2 can then drive the motor vehicle via the second input shaft 10.2, the third gear set 15.3, and the second countershaft 13.2. In addition, the second electric motor 12 can apply additional torque to the second input shaft 10.2.

[0066] A fourth function IV results in the fourth combustion gear V4 when the first shift element 17.1 and the fifth shift element 17.5 are engaged. The drive device 2 can then drive the motor vehicle via the second input shaft 10.2, the fourth gear set 15.4, and the second countershaft 13.2. In addition, the second electric motor 12 can apply additional torque to the second input shaft 10.2.

[0067] A fifth function V results in the first electric gear stage E1.1 for the first electric motor 11 when only the second shift element 17.2 is engaged. The first electric motor 11 can then drive the motor vehicle via the first input shaft 10.1, the first gear set 15.1, and the first countershaft 13.1.

[0068] A sixth function VI results in the second electric gear stage E1.2 for the first electric motor 11 when only the sixth shift element 17.6 is engaged. The first electric motor 11 can then drive the motor vehicle via the first input shaft 10.1, the fifth gear set 15.5, and the second countershaft 13.2.

[0069] A seventh function VII results in the third electric gear stage E1.3 for the first electric machine 11 when the fourth shift element 17.4 and the seventh shift element 17.7 are engaged. The first electric machine 11 can then drive the motor vehicle via the first input shaft 10.1, the second input shaft 10.2, the third gear set 15.3, and the second countershaft 13.2. Additionally, the second electric machine 12 or the drive device 2 can apply additional torque to the second input shaft 10.2.

[0070] An eighth function VIII results in the first electric gear stage E2.1 for the second electric machine 12 when the second shifting element 17.2 and the seventh shifting element 17.7 are engaged, with the first shifting element 17.1 being engaged in particular. The second electric machine 12 can then drive the motor vehicle via the second input shaft 10.2, the first input shaft 10.1, the first gear set 15.1, and the first countershaft 13.1. In addition, the first electric machine 11 can apply additional torque to the first input shaft 10.1.

[0071] A ninth function IX results in the second electric gear stage E2.2 for the second electric machine 12 when only the third shift element 17.3 is closed, with the first shift element 17.1 being open in particular. The second electric machine 12 can then drive the motor vehicle via the second input shaft 10.2, the second gear set 15.2, and the first countershaft 13.1.

[0072] A tenth function X results in the third electric gear stage E2.3 for the second electric machine 12 when only the fourth shift element 17.4 is closed, with the first shift element 17.1 being open in particular. The second electric machine 12 can then drive the motor vehicle via the second input shaft 10.2, the third gear set 15.3, and the second countershaft 13.2.

[0073] An eleventh function XI results in the fourth electric gear stage E2.4 for the second electric machine 12 when only the fifth shift element 17.5 is engaged, with the first shift element 17.1, in particular, being disengaged. The second electric machine 12 can then drive the motor vehicle via the second input shaft 10.2, the fourth gear set 15.4, and the second countershaft 13.2.

[0074] The twelfth function XII results in serial operation S or charging operation L when the first switching element 17.1 is closed. The drive device 2 then drives the second electric machine 12, which is operated as a generator, via the second input shaft 10.2. The electrical energy generated in the second electric machine 12 can be used in serial operation S to operate the first electric machine 11, in which case, for example, the first electric gear stage E1.1 for the first electric machine 11 can be engaged when the second switching element 17.2 is closed, or the second electric gear stage E1.2 for the first electric machine 11 can be engaged when the sixth switching element 17.6 is closed. Alternatively, the electrical energy generated in the second electric machine 12 is fed into an energy storage device in charging operation L.A portion of the electrical energy generated by the second electrical machine 12 can also be used to operate the first electrical machine 11 and a remaining portion can be fed into the energy storage device. Reference symbol 1 Motor vehicle powertrain 2 drive device 4 connecting shaft 5 differential gears 6 drive wheel 7 Drive wheel 8 Gearbox housing 10.1 first input shaft 10.2 second input shaft 11 first electric machine 11.1 Rotor 11.2 Stator 12 second electric machine 12.1 Rotor 12.2 Stator 13.1 Countershaft 13.2 Countershaft 14.1 first fixed gear 14.2 second fixed gear 14.3 third fixed gear 14.4 fourth fixed gear 15.1 first wheelset 15.2 second wheelset 15.3 third wheelset 15.4 fourth wheelset 15.5 fifth wheelset 16.1 first idler gear 16.2 second idler gear 16.3 third idler gear 16.4 fourth idler gear 16.5 fifth idler gear 17.1 first switching element 17.2 second switching element 17.3 third switching element 17.4 fourth switching element 17.5 fifth switching element 17.6 sixth switching element 17.7 seventh switching element 18 Overlap area 19 Planetary gear set 19.1 first element of the planetary gear set 19.2 second element of the planetary gear set 19.3 third element of the planetary gear set 100 gearboxes 200 gearboxes 300 gearboxes E1.1 first electric gear stage for the first electric machine E1.2 second electric gear stage for the first electric machine E1.3 third electric gear stage for the first electric machine E2.1 first electric gear stage for the second electric machine E2.2 second electric gear stage for the second electric machine E2.3 third electric gear stage for the second electric machine E2.4 fourth electric gear stage for the second electric machine V1 first combustion gear V2 second combustion gear V3 third combustion gear V4 fourth combustion gear S serial operation L Charging mode I first transmission function II second transmission function III third transmission function IV fourth transmission function V fifth transmission function VI sixth transmission function VII seventh transmission function VIII eighth transmission function IX ninth transmission function X tenth transmission function XI eleventh gear function XII twelfth gear function

Claims

[1] Transmission (200, 300) for a motor vehicle with a drive device (2), comprising: a first input shaft (10.1), a second input shaft (10.2), at least one gear set (15.1, 15.2, 15.3, 15.4, 15.5) for forming at least one gear stage (V1, V2, V3, V4, E1.1, E1.2, E1.3, E2.1, E2.2, E2.3, E2.4), at least one countershaft (13.1, 13.2) for the rotationally fixed connection of the transmission (200, 300) to an output, wherein a first electric machine (11) is connected to the first input shaft (10.1) in a rotationally fixed manner or can be detachably and rotationally fixedly connected via a switching element, wherein the drive device (2) is connected to the second input shaft (10.2) in a rotationally fixed manner or can be detachably and rotationally fixedly connected via a switching element (17.1), wherein a second electric machine (12) is connected to the second input shaft (10.2) in a rotationally fixed manner or can be detachably and rotationally fixedly connected via a switching element, wherein the first electrical machine (11) and the second electrical machine (12) are arranged overlapping one another and coaxially in the axial direction, characterized by that at least one loose wheel is provided which can be detachably and non-rotatably connected to the first input shaft (10.1) and which meshes with at least one fixed wheel which is non-rotatably connected to the countershaft (13.1, 13.2) or at least one fixed wheel (14.1) which is non-rotatably connected to the first input shaft (10.1) and which meshes with at least one loose wheel (16.1, 16.5) which can be detachably and non-rotatably connected to the countershaft (13.1, 13.2), in each case to form at least one gear set (15.1, 15.5), wherein at least one switching element (17.2, 17.6) is provided for connecting the first input shaft (10.1) or the countershaft (13.1, 13.2) to the at least one idler gear (16.1, 16.5), and / or wherein at least one idler gear (16.4) is provided which is detachably and non-rotatably connectable to the second input shaft (10.2) and meshes with at least one fixed gear (14.3) which is non-rotatably connected to the countershaft (13.1, 13.2) or at least one fixed gear (14.2) which is non-rotatably connected to the second input shaft (10.2) and meshes with at least one idler gear (16.2, 16.3) which is detachably and non-rotatably connectable to the countershaft (13.1, 13.2), in each case to form at least one gear set (15.2, 15.3, 15.4), wherein at least one switching element (17.3, 17.4, 17.5) is provided for connecting the second input shaft (10.2) or a countershaft (13.1, 13.2) to the at least one idler gear (16.2, 16.3, 16.4). [2] Transmission (200, 300) according to claim 1, wherein the second electric machine (12) is completely covered in the axial direction by the first electric machine (11) or the first electric machine (11) is completely covered in the axial direction by the second electric machine (12). [3] Transmission (200, 300) according to claim 1 or 2, wherein the first electric machine (11) is larger than the second electric machine (12) and the second electric machine (12) is arranged at least partially radially inside the first electric machine (11). [4] Transmission (200, 300) according to one of the preceding claims, comprising at least one first planetary gear set for forming at least one gear stage (V1, V2, V3, V4, E1.1, E1.2, E1.3, E2.1, E2.2, E2.3, E2.4). [5] Transmission (200, 300) according to one of the preceding claims, comprising at least one second planetary gear set (19) for increasing the torque of one of the electric machines (11, 12). [6] Transmission (200, 300) according to claim 5, wherein the planetary gear set (19) comprises a first element (19.1), a second element (19.2) and a third element (19.3), wherein the electric machine (11, 12) is connected in a rotationally fixed manner to the first element (19.1), wherein the second element (19.2) is connected in a rotationally fixed manner to the first or second input shaft (10.1, 10.2) and wherein the third element (19.3) is fixed. [7] Transmission (200, 300) according to one of the preceding claims, wherein at least two switching elements (17.5, 17.7) are combined to form a multiple switching device with a common actuator. [8] Transmission (200, 300) according to one of the preceding claims, comprising at least two gear stages (V1, V2, V3, V4, E1.1, E1.2, E1.3, E2.1, E2.2, E2.3, E2.4), wherein in one gear stage (E1.1, E1.2, E1.3) the first electric machine (11) can drive the motor vehicle via the first input shaft (10.1) and in a further gear stage (V1, V2, V3, V4) the drive device (2) can drive the motor vehicle via the second input shaft (10.2). [9] Transmission (200, 300) according to one of the preceding claims, wherein one of the electrical machines (12) is designed as an internal rotor and the other of the electrical machines (11) is designed as an external rotor. [10] Transmission (200, 300) according to one of the preceding claims, wherein the first input shaft (10.1) and the second input shaft (10.2) are arranged coaxially. [11] Transmission (200, 300) according to claim 10, wherein the second input shaft (10.2) is designed as a solid shaft and the first input shaft (10.1) is designed as a hollow shaft arranged to at least partially axially overlap the second input shaft (10.2). [12] Drive train (1) for a motor vehicle with a transmission (200, 300) according to one of the preceding claims and with a drive device (2). [13] Motor vehicle with a drive train (1) according to claim 12.

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