Hybridgetriebe

Abstract

Hybrid transmission (18) for a motor vehicle drive train (12) of a motor vehicle (10), comprising: a first transmission input shaft (24) for operatively connecting the hybrid transmission to an internal combustion engine (16) of the motor vehicle; a second transmission input shaft (26) for operatively connecting the hybrid transmission (18) to a first electric drive motor (14) of the motor vehicle; an output shaft (28) for operatively connecting the hybrid transmission (18) to an output (30); a planetary gear set (RS) which is drivingly connected to the first transmission input shaft (24) and the second transmission input shaft (26); spur gear pairs (ST1, ST2, ST3) arranged in several gear set levels to form gear steps; and several gearshift devices with shift elements (A, B, C, D, E) for engaging gear steps, wherein a first spur gear pair (ST1) of the spur gear pairs (ST1, ST2, ST3) is assigned to the first transmission input shaft (24) to form gear stages; a second spur gear pair (ST2) and a third spur gear pair (ST3) of the spur gear pairs (ST1, ST2, ST3) are assigned to the first transmission input shaft (24) and the output shaft (28) to form gear stages; the output shaft (28) is designed as a hollow shaft and surrounds the second transmission input shaft (26) designed as a solid shaft at least in sections to enable a connection to a differential of the output (30) in a transmission center; or wherein the second transmission input shaft (26) is designed as a hollow shaft and surrounds the output shaft (28) designed as a solid shaft at least in sections in order to enable a connection to a differential of the output (30) on an outer side of the transmission.

Description

[0001] The present invention relates to a hybrid transmission, a motor vehicle drive train with such a hybrid transmission, a motor vehicle with such a motor vehicle drive train and a method for operating such a motor vehicle drive train.

[0002] Vehicles are increasingly being equipped with hybrid drives, i.e. with at least two different drive sources. Hybrid drives can help reduce fuel consumption and pollutant emissions. Drivetrains with an internal combustion engine and one or more electric motors as parallel hybrids or mixed hybrids have largely become established. Such hybrid drives feature an essentially parallel arrangement of the internal combustion engine and the electric drive in the power flow. This allows both a superposition of the drive torques and control with purely internal combustion engine drive or purely electric motor drive. Since the drive torques of the electric drive and the internal combustion engine can be added together depending on the control, a comparatively smaller design of the internal combustion engine and / or its temporary shutdown is possible.This allows for a significant reduction in CO2 emissions without any significant loss of performance or comfort. The possibilities and advantages of an electric drive can thus be combined with the range, performance, and cost advantages of internal combustion engines.

[0003] A disadvantage of the aforementioned hybrid drives is their generally more complex design, as both drive sources typically transmit power to a single drive shaft via a single transmission. This makes such transmissions complex and costly to produce. Reducing the complexity of a hybrid transmission's design usually results in a loss of variability.

[0004] This disadvantage can be at least partially overcome by dedicated hybrid transmissions (DHTs), in which an electric motor is integrated into the transmission to provide the full range of functions. For example, the mechanical transmission part of the transmission can be simplified, for example by eliminating the reverse gear and using at least one electric motor instead.

[0005] Dedicated hybrid transmissions can be derived from familiar transmission concepts, such as dual-clutch transmissions, torque converter planetary transmissions, continuously variable transmissions (CVTs), or automated manual transmissions. The electric motor is preferably integrated into the transmission.

[0006] From the published patent application DE 10 2013 215 114 A1, a hybrid drive of a motor vehicle is known, which has an internal combustion engine with a drive shaft, an electric machine operable as a motor and as a generator with a rotor, an automated manual transmission designed in countershaft design with an input shaft and at least one output shaft, and a superposition transmission designed in planetary design with two input elements and one output element.In this hybrid drive, the superposition gear is arranged coaxially above a free end of the output shaft, and the first input element of the superposition gear is connected in a rotationally fixed manner to a hollow shaft arranged coaxially above the output shaft. The hollow shaft is connected in a rotationally fixed manner to an idler gear of the immediately axially adjacent spur gear stage of the manual transmission via a coupling switching element for coupling the combustion engine, and in a rotationally fixed manner to the second input element or the output element of the superposition gear via a bridging switching element for bridging the superposition gear. Furthermore, the second input element of the superposition gear is permanently drive-connected to the rotor of the electric motor, and the output element of the superposition gear is connected in a rotationally fixed manner to the output shaft.

[0007] Further hybrid drives are known from the published patent applications DE 10 2021 204 616 A1, DE 10 2016 200 583 A1, DE 10 2011 005 562 A1 and DE 10 2008 037 408 A1.

[0008] Against this background, a person skilled in the art is faced with the task of creating a compact hybrid transmission with a simple mechanical design. Furthermore, a drivetrain configuration should preferably be implemented in which the hybrid transmission is positioned coaxially to the output shafts and the combustion engine and / or the electric drive motor can be arranged axially parallel to it. In particular, a transmission is to be created that has up to three gear ratios and enables loading-in-neutral, electrodynamic starting (EDA), and electrodynamic shifting (EDS).

[0009] The above task is solved by a hybrid transmission for a motor vehicle drive train of a motor vehicle, with: a first transmission input shaft for operatively connecting the hybrid transmission to an internal combustion engine of the motor vehicle; a second transmission input shaft for operatively connecting the hybrid transmission to a first electric drive motor of the motor vehicle; an output shaft for operatively connecting the hybrid transmission to an output; a planetary gear set drivingly connected to the first transmission input shaft and the second transmission input shaft; spur gear pairs arranged in several gear set levels to form gear steps; and several gearshift devices with switching elements for engaging gear steps, whereby a first spur gear pair of the spur gear pairs is assigned to the first transmission input shaft to form gear stages; a second spur gear pair and a third spur gear pair of the spur gear pairs are assigned to form gear stages of the first transmission input shaft and the output shaft; the output shaft is designed as a hollow shaft and surrounds the second transmission input shaft, which is designed as a solid shaft, at least in sections, in order to enable a connection to a differential of the output in a transmission center; or wherein the second transmission input shaft is designed as a hollow shaft and surrounds the output shaft designed as a solid shaft at least in sections in order to enable a connection to a differential of the output on an outer side of the transmission.

[0010] The above object is further achieved by a motor vehicle drive train for a motor vehicle, comprising: a hybrid transmission as previously defined; an internal combustion engine connectable to the first transmission input shaft; and a first electric drive motor which is drivingly connected to the second transmission input shaft.

[0011] The above task is finally solved by a motor vehicle with: a motor vehicle powertrain as previously defined; and an energy storage device for storing energy to supply the first electric drive machine, a second electric drive machine and / or a further electric machine.

[0012] Preferred embodiments of the invention are described in the dependent claims. It is understood that the features mentioned above and those to be explained below can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the present invention. In particular, the motor vehicle drive train, the motor vehicle, and the method can be designed according to the embodiments described for the hybrid transmission in the dependent claims.

[0013] A compact hybrid transmission can be created in a technically simple manner by using a first transmission input shaft for operatively connecting the hybrid transmission to an internal combustion engine and a second transmission input shaft for operatively connecting the hybrid transmission to a first electric drive motor. An operative connection can be designed to be either switchable or non-switchable. A planetary gear set that is drive-connected to the first transmission input shaft and the second transmission input shaft allows for the creation of a high-quality and compact hybrid transmission. A first spur gear pair assigned to the first transmission input shaft and a second and third spur gear pair assigned to the first transmission input shaft and the output shaft, respectively, allows for the creation of a highly compact, functionally comprehensive hybrid transmission.A highly efficient hybrid transmission can be created because few gear meshes are required to set up up to three hybrid gear ratios, sometimes in multiple variants. Furthermore, the hybrid transmission can be used to set up a purely electric gear ratio, as well as an electrodynamic superposition state and a load-in-neutral state. The hybrid transmission, and in particular the gear set used in the hybrid transmission, has a technically simple design, so that the shift elements can preferably be shifted using just three actuators. The hybrid transmission can achieve low component loads and low transmission losses, both in the combustion engine and electrically. The hybrid transmission comprises an advantageous gear ratio range, enabling output-assisted shifting, electrodynamic starting, and electrodynamic shifting.A transition from the electrodynamic superposition state or from the charge-to-neutral state is possible in all three hybrid gear ratios of the hybrid transmission. It is understood that all hybrid gear ratios can also be operated as pure combustion gear ratios, or as pure electric gear ratios if an internal combustion engine clutch is installed. It is also understood that a main electric motor can also be used as the main propulsion machine instead of the internal combustion engine.

[0014] In an advantageous embodiment, the first electric drive motor is connected to the hybrid transmission on a transmission side that is opposite a connection side of the internal combustion engine, wherein, starting from a connection side of the internal combustion engine, the third spur gear pair, the second spur gear pair, the first spur gear pair, and the planetary gear set are arranged in this order. Alternatively, the first electric drive motor is connected to the hybrid transmission on a transmission side that is opposite a connection side of the internal combustion engine, wherein, starting from the connection side of the internal combustion engine, the first spur gear pair, the planetary gear set, the second spur gear pair, and the third spur gear pair are arranged in this order.The two alternative connection sequences described above, in which the individual connections of the transmission components remain the same, make it possible to create a hybrid transmission that can be easily adapted to different installation space requirements.

[0015] In a further advantageous embodiment, in two of the spur gear pairs for forming the gear steps, the arrangement of the idler gear and the arrangement of the fixed gear are interchangeable. Additionally or alternatively, an axial arrangement of two of the spur gear pairs for forming the gear steps is interchangeable. Furthermore, additionally or alternatively, the first transmission input shaft is designed without a shift element. It is understood that when the spur gear pairs are exchanged, the corresponding shift element is also exchanged with regard to its arrangement position and is preferably arranged on the shaft on which the corresponding idler gear of the spur gear pair is also arranged. The interchangeability of both the idler gear and the fixed gear, or the axial arrangement, makes it possible to create a variable hybrid transmission that can be easily adapted to different installation space requirements.A transmission input shaft designed without shifting elements can simplify the production and assembly of the hybrid transmission. In particular, the first transmission input shaft can be manufactured cost-effectively.

[0016] In a further advantageous embodiment, the hybrid transmission has a transmission input shaft that is drivingly connected to the first transmission input shaft and arranged axially parallel to the first transmission input shaft. Additionally or alternatively, the output shaft is drivingly connected to a differential of the output, wherein the differential comprises a differential shaft for transmitting drive power from the hybrid transmission to the wheels of the motor vehicle, which differential shaft is arranged axially parallel to the output shaft and is designed to penetrate the first electric drive motor to enable the first electric drive motor to be arranged around the differential shaft.

[0017] Preferably, the transmission input shaft is drivingly connected to the first transmission input shaft by means of a chain or a gear chain. The advantageous arrangement described above allows for an axially parallel connection of the combustion engine to a transmission axis of the hybrid transmission. It is understood that the transmission input shaft may additionally comprise a damper or a damping element. By arranging the first electric drive motor around a transmission shaft, in particular the differential shaft, a highly efficient and space-saving arrangement and preferably mounting of the first electric drive motor in the hybrid transmission can be achieved. The compactness of the hybrid transmission and the motor vehicle drive train can be further increased.

[0018] In a further advantageous embodiment, a planetary gear carrier of the planetary gear set is drive-connectable to the output shaft, wherein the sun gear of the planetary gear set is drive-connected to the first transmission input shaft by means of the first spur gear pair of the spur gear pairs to form the gear stages, and the ring gear of the planetary gear set is drive-connected to the second transmission input shaft. Alternatively, a planetary gear carrier of the planetary gear set is drive-connectable to the output shaft, wherein the ring gear of the planetary gear set is drive-connected to the first transmission input shaft by means of the first spur gear pair of the spur gear pairs to form the gear stages, and the sun gear of the planetary gear set is drive-connected to the second transmission input shaft.Thanks to the two alternative connections mentioned above, the first electric drive motor can either operate at a low compensating speed during electrodynamic starting or electrodynamic shifting, or it can only apply a low support torque during electrodynamic starting and electrodynamic shifting. Furthermore, the two alternative connections can increase or decrease the duration of generator operation during electrodynamic starting.

[0019] In a further advantageous embodiment, the hybrid transmission has an internal combustion engine clutch for releasably and driveably connecting the first transmission input shaft to the internal combustion engine, wherein the internal combustion engine clutch is preferably arranged on the transmission input shaft. It is understood that the internal combustion engine clutch can be designed as a dog-type shift element or a friction shift element. An internal combustion engine clutch enables the internal combustion engine to be decoupled from the hybrid transmission. This allows for a highly efficient, purely electric driving mode. An internal combustion engine clutch in the form of a friction shift element or a friction clutch enables a so-called momentum start of the internal combustion engine. Furthermore, the internal combustion engine clutch can serve as an emergency starting element for the internal combustion engine.

[0020] In a further advantageous embodiment, a first shifting element is designed to drive-connect the first transmission input shaft to the output shaft by means of the second spur gear pair of the spur gear pairs to form gear stages. Additionally or alternatively, a second shifting element is designed to drive-connect the first transmission input shaft to the output shaft by means of the third spur gear pair of the spur gear pairs to form gear stages.

[0021] Additionally or alternatively, a third shifting element is designed to lock the planetary gear set. Further additionally or alternatively, a fourth shifting element is designed to drive-effectively connect the planetary gear set to the output shaft. Finally, further additionally or alternatively, a fifth shifting element is designed to drive-effectively connect the second transmission input shaft to the output shaft. This advantageous arrangement of the shifting elements allows the hybrid transmission to create three hybrid gear stages, sometimes with multiple variants, as well as a purely electric gear stage, an electrodynamic superposition state, and a load-in-neutral state. The planetary gear set is preferably locked by a drive-effectively connecting the ring gear to the planet gear carrier of the planetary gear set.It is understood that other blocking alternatives, such as connecting the sun gear to the ring gear or connecting the sun gear to the planet gear carrier, are also conceivable.

[0022] In a further advantageous embodiment, the hybrid transmission has exactly three spur gear pairs, exactly one planetary gear set, and exactly five shift elements to form three hybrid gear ratios. This allows for high functionality combined with a high degree of compactness of the hybrid transmission. In particular, a hybrid transmission with advantageous installation space requirements and weight can be created.

[0023] The output shaft is designed as a hollow shaft and surrounds the second transmission input shaft, which is designed as a solid shaft, at least in sections, to enable a connection to a differential of the output in a transmission center. Alternatively, the second transmission input shaft is designed as a hollow shaft and surrounds the output shaft, which is designed as a solid shaft, at least in sections, to enable a connection to a differential of the output on an outer side of the transmission. By designing some transmission shafts as hollow shafts and advantageously arranging them at least in sections around other transmission shafts, the compactness of the hybrid transmission can be further improved. Furthermore, the two alternatives mentioned above enable a variable arrangement of the output, so that the hybrid transmission can be easily adapted to different installation space requirements.

[0024] In a further advantageous embodiment, the shifting elements are designed as positive-locking shifting elements. Additionally or alternatively, at least two of the shifting elements, preferably four shifting elements, are designed as double-locking shifting elements and can be actuated by a double-acting actuator. Positive-locking shifting elements enable a highly efficient and cost-effective hybrid transmission. The technical design and operation of the hybrid transmission can be further simplified by a double-locking element. In particular, a double-locking element can be switched using a single actuator.

[0025] In a further advantageous embodiment, the motor vehicle drive train preferably comprises a further electric machine that is drivingly connected to the first transmission input shaft. The first electric drive machine and / or preferably the further electric machine can be controlled as a starter generator for starting the internal combustion engine. Additionally or alternatively, the first electric drive machine and / or preferably the further electric machine can be controlled as a charging generator for charging an energy storage device. The further electric machine is preferably designed as a high-voltage starter generator. This makes it possible to create an efficient motor vehicle drive train. In particular, fuel consumption can be reduced.It is understood that an additional starter for the combustion engine can be dispensed with, since the first electric drive motor and / or preferably the further electric motor can tow the combustion engine.

[0026] In a further advantageous embodiment, an output of the hybrid transmission can be drive-connected to a first motor vehicle axle, wherein a second motor vehicle axle comprises an electric axle with a second electric drive motor. This makes it technically simple to create a hybrid drive train with all-wheel drive. Furthermore, the motor vehicle drive train can easily enable shifting without interruption in tractive force, since the electric axle can maintain tractive force during shifts in the hybrid transmission. Furthermore, a fail-safe drive train for a motor vehicle can be created, since a so-called serial driving mode can be set up in the event of a depleted energy storage device for the second electric drive motor.In serial driving mode, the electric drive motor is preferably operated by the internal combustion engine as a generator, and the energy thus generated is made available to the second electric drive motor. This allows for a highly variable motor vehicle drive train that can be driven and started electrically, especially when the energy storage device is empty.

[0027] Interlocking a planetary gear set involves connecting two gears and / or the planetary gear carrier and a gear of the planetary gear set in a drive-effective manner, so that they rotate together at the same speed around the same point, preferably the center of the planetary gear set. When interlocking two gears and / or a planetary gear carrier and a gear of the planetary gear set, the planetary gear set preferably acts like a shaft; in particular, no gear ratio is transmitted within the planetary gear set.

[0028] In this context, "drive-effectively connected" refers in particular to a non-switchable connection between two components intended for the permanent transmission of a rotational speed, torque, and / or drive power. The connection can be made either directly or via a fixed transmission ratio. The connection can be made, for example, via a fixed shaft, a gearing, in particular a spur gearing, and / or a belt drive, in particular a traction drive.

[0029] In this context, "drive-connectable," "can be connected to a drive," or "is designed for a drive-connected connection" refers, in particular, to a switchable connection between two components, which, in a closed state, is intended for the temporary transmission of a rotational speed, a torque, and / or a drive power. In an open state, the switchable connection preferably temporarily transmits essentially no rotational speed, no torque, and / or no drive power.

[0030] Stand-by charging or charging-in-neutral means, in particular, operating the electric drive motor as a generator, preferably when stationary with the combustion engine running, in order to fill an energy storage unit and / or to supply on-board electronics.

[0031] In this context, an actuator is, in particular, a component that converts an electrical signal into a mechanical movement. Actuators used with dual switching elements preferably perform movements in two opposite directions, switching one switching element of the dual switching element in the first direction and switching the other switching element in the second direction.

[0032] A gear change, particularly a serial shift, occurs in particular by disengaging a shifting element and / or a clutch and simultaneously engaging the shifting element and / or the clutch for the next higher or lower gear. The second shifting element and / or the second clutch thus gradually takes over the torque from the first shifting element and / or the first clutch until, at the end of the gear change, the entire torque is taken over by the second shifting element and / or the second clutch. With prior synchronization, a gear change can occur more quickly; positive-locking shifting elements can preferably be used.

[0033] An internal combustion engine can be any machine that can generate a rotary motion by burning a fuel such as gasoline, diesel, kerosene, ethanol, liquefied petroleum gas, LPG, etc. An internal combustion engine can be, for example, a gasoline engine, a diesel engine, a rotary engine, or a two-stroke engine.

[0034] In serial driving or crawling, an electric drive motor of a motor vehicle is powered by a combustion engine of the motor vehicle. The energy thus generated is then made available to another electric drive motor of the motor vehicle to provide drive power.

[0035] An electric vehicle axle, or simply an electric axle, is preferably a non-main drive axle of a motor vehicle, in which drive power can be transferred to the wheels of the motor vehicle by means of an electric drive motor. It is understood that the electric drive motor can also be connected via a transmission. Traction can be fully or partially maintained by means of an electric axle when a gear change occurs in the transmission for a main drive axle. Furthermore, all-wheel drive functionality can be implemented at least partially by means of an electric axle.

[0036] An electrodynamic starting element (EDA) ensures that the speed of the combustion engine and the electric drive motor is superimposed via one or more planetary gear sets, enabling a motor vehicle to start from a standstill with the combustion engine running, preferably without a friction clutch. The electric drive motor supports a torque. Preferably, the combustion engine can no longer be separated from the transmission by a starting clutch or the like. By using an EDA, the starter, generator, and starting clutch or hydrodynamic converter can be eliminated. In particular, an EDA is so compact that all components fit into the standard clutch housing without extending the transmission.The electrodynamic starting element can, for example, be firmly connected to an internal combustion engine, and in particular to a flywheel of an internal combustion engine, via a softly tuned torsional damper. This allows the electric drive motor and the internal combustion engine to be operated either simultaneously or alternatively. When the vehicle stops, the electric drive motor and the internal combustion engine can be switched off. Due to the good controllability of the electric drive motor, a very high starting quality is achieved, which can be equivalent to that of a drive with a torque converter clutch.

[0037] In an electrodynamic shift (EDS), as with EDA starting, the speed of the combustion engine and the electric drive motor is superimposed via one or more planetary gear sets. At the start of the shift, the torques of the electric drive motor and the combustion engine are adjusted so that the shift element to be disengaged is load-free. After this shift element is opened, the speed is adjusted while maintaining the tractive force, so that the shift element to be engaged becomes synchronous. After the shift element is closed, the load is distributed between the combustion engine and the electric drive motor as desired, depending on the hybrid operating strategy.The electrodynamic shifting system has the advantage that the shift element of the target gear to be engaged is synchronized through the interaction of the electric drive motor and the combustion engine, with the electric drive motor preferably being precisely controllable. A further advantage of the EDL shifting system is that high tractive effort can be achieved, since the torques of the combustion engine and the electric motor are combined in the hybrid transmission.

[0038] The invention is described and explained in more detail below using selected embodiments in conjunction with the accompanying drawings. They show: Fig. 1 a schematic plan view of a motor vehicle with a motor vehicle drive train according to the invention; Fig. 2 a schematic representation of a variant of a hybrid transmission according to the invention; Fig. 3 schematically shows the switching states of the hybrid transmission according to the Fig. 2; Fig. 4 a schematic representation of another variant of a hybrid transmission; Fig. 5 a schematic representation of another variant of a hybrid transmission; Fig. 6 a schematic representation of another variant of a hybrid transmission; Fig. 7 a schematic representation of another variant of a hybrid transmission; Fig. 8 a schematic representation of another variant of a hybrid transmission; Fig. 9 a schematic representation of another variant of a hybrid transmission; and Fig. 10 a schematic representation of another variant of a hybrid transmission.

[0039] In Fig. 1 schematically shows a motor vehicle 10 with a motor vehicle drive train 12. The motor vehicle drive train 12 has a first electric drive motor 14 and an internal combustion engine 16, which are connected to a front axle of the motor vehicle 10 by means of a hybrid transmission 18. In the example shown, the motor vehicle drive train 12 further comprises an optional electric axle with a second electric drive motor 20, which is connected to a rear axle of the motor vehicle 10. It is understood that a reverse connection can also be made, so that the hybrid transmission 18 is connected to the rear axle of the motor vehicle 10 and the front axle of the motor vehicle 10 comprises the electric axle.By means of the motor vehicle drive train 12, drive power of the first electric drive motor 14, the internal combustion engine 16, and / or the optional second electric drive motor 20 is supplied to the wheels of the motor vehicle 10. The motor vehicle 10 further comprises an energy storage device 22 for storing energy that serves to supply the first electric drive motor 14 and / or the second electric drive motor 20.

[0040] Fig. 2 shows a simplified variant of a hybrid transmission 18 according to the invention. The hybrid transmission 18 has a first transmission input shaft 24 and a second transmission input shaft 26, which are designed to transmit drive power from the drive machines 14, 16 to the hybrid transmission 18.

[0041] The hybrid transmission 18 further comprises an output shaft 28 and a planetary gear set RS as well as a total of three gear-forming spur gear pairs, which are designated ST1 - ST3.

[0042] The first electric drive machine 14 is drivingly connected to the second transmission input shaft 26 via a gear chain, wherein the gear chain comprises a fixed gear arranged on an output shaft of the rotor shaft of the first electric machine 14, which is in engagement with another fixed gear, wherein this fixed gear is in engagement with a fixed gear arranged on the second transmission input shaft 26.

[0043] The first spur gear pair ST1 comprises a fixed gear arranged on the first transmission input shaft 24, which meshes with a fixed gear arranged on a hollow shaft, wherein the hollow shaft is arranged on the second transmission input shaft 26 and is drive-effectively connected to a ring gear of the planetary gear set RS.

[0044] The second spur gear pair ST2 comprises a loose gear arranged on the first transmission input shaft 24, which is in engagement with a fixed gear arranged on the output shaft 28.

[0045] The third spur gear pair ST3 also comprises a loose gear arranged on the first transmission input shaft 24, which is in engagement with a fixed gear arranged on the output shaft 28.

[0046] The output shaft 28 further comprises an output gear. Furthermore, the output shaft 28 is designed as a hollow shaft and surrounds the second transmission input shaft 26 at least in sections.

[0047] In the embodiment shown, the hybrid transmission 18 has a total of five shift elements, which are designated A - E.

[0048] By engaging the first shift element A, the idler gear of the second spur gear pair ST2 can be drive-connected to the first transmission input shaft 24. Consequently, a drive-effective connection is established between the first transmission input shaft 24 and the output shaft 28.

[0049] By engaging the second shift element B, the idler gear of the third spur gear pair ST3 can be connected in a drive-effective manner to the first transmission input shaft 24, whereby a drive-effective connection is established between the first transmission input shaft 24 and the output shaft 28.

[0050] By engaging the third shift element C, the ring gear of the RS planetary gear set can be connected to a planetary gear carrier of the RS planetary gear set in a drive-effective manner. The RS planetary gear set is thus locked by engaging the third shift element C.

[0051] The fourth switching element D is designed to drive-effectively connect the planetary gear carrier of the planetary gear set RS to the output shaft 28.

[0052] The fifth shift element E is designed to drive-effectively connect the second transmission input shaft 26 to the output shaft 28.

[0053] The hybrid transmission 18 accordingly comprises a planetary gear set RS, the ring gear of which is drive-connected to the first transmission input shaft 24 via the first spur gear pair ST1. The planetary gear carrier of the planetary gear set RS is drive-connectable to the output shaft 28, and the sun gear of the planetary gear set RS is drive-connected to the second transmission input shaft 26.

[0054] The first transmission input shaft 24 and the second transmission input shaft 26 are designed as solid shafts and are arranged axially parallel to one another.

[0055] The output shaft 28 is designed as a hollow shaft and is arranged at least in sections around the second transmission input shaft 26.

[0056] The first switching element A is combined with the second switching element B to form a double switching element. The third switching element C is combined with the fourth switching element D to form a double switching element.

[0057] It is understood that the shift elements A-E are preferably designed as positive-locking shift elements, for example, claw shift elements. It is further understood that a fixed gear ratio, for example in the form of an additional planetary gear set or a spur gear stage, can be connected downstream of the gear set of the hybrid transmission 18. A differential is particularly preferably connected downstream of the gear set.

[0058] In the embodiment shown, the first electric drive machine 14 is connected to the hybrid transmission 18 on a transmission side which is opposite a connection side of the combustion engine 16 (not shown).

[0059] From the connection side of the combustion engine 16 (not shown), first the first spur gear pair ST1 is arranged, then the planetary gear set RS, then the double switching element comprising the third switching element C and the fourth switching element D, then the second spur gear pair ST2, then the double switching element comprising the first switching element A and the second switching element B, then the third spur gear pair ST3 and finally the fifth switching element E.

[0060] In Fig. 3 schematically shows the switching states of the hybrid transmission 18 according to the Fig. 2 in a shift matrix 32. The first column of the shift matrix 32 shows the hybrid gear stages H1 - H3, an electric gear stage E1, an electrodynamic superposition state EDA, and the charge-in-neutral state LiN. The second to sixth columns show the shift states of the shift elements A - E, where an "X" means that the respective shift element is closed, i.e., connects the associated transmission components to one another in a drive-effective manner. If no entry is present, it can be assumed that the corresponding shift element is open, i.e., is not transmitting any drive power.

[0061] A first variant of the first hybrid gear stage H1.1 can be set up by closing the fourth switching element D and the fifth switching element E.

[0062] Closing the third switching element C and the fifth switching element E establishes a second variant of the first hybrid gear stage H1.2.

[0063] A third variant of the first hybrid gear stage H1.3 can be set up by closing the third switching element C and the fourth switching element D.

[0064] Closing the first switching element A and the fifth switching element E establishes a first variant of the second hybrid gear stage H2.1.

[0065] A second variant of the second hybrid gear stage H2.2 can be set up by closing the first switching element A and the fourth switching element D.

[0066] Closing the first switching element A and the third switching element C establishes a third variant of the second hybrid gear stage H2.3.

[0067] A first variant of the third hybrid gear stage H3.1 can be set up by closing the second switching element B and the fifth switching element E.

[0068] Closing the second switching element B and the fourth switching element D establishes a second variant of the third hybrid gear stage H3.2.

[0069] A third variant of the third hybrid gear stage H3.3 can be set up by closing the second switching element B and the third switching element C.

[0070] The electric gear stage E1 can be set by closing the fifth switching element E.

[0071] An electrodynamic superposition state EDA can be established by closing the fourth switching element D.

[0072] Closing the third switching element C establishes the charge-in-neutral LiN state.

[0073] It is understood that depending on how the individual shift elements A - E are combined to form double shift elements, individual gears may not be engaged. For example, the third variant of the first hybrid gear H1.3 cannot be engaged if the third shift element C is combined with the fourth shift element D to form a double shift element. Furthermore, the second variant of the first hybrid gear H1.2 cannot be engaged if the third shift element C is combined with the fifth shift element E to form a double shift element.

[0074] For combustion engine or hybrid driving, three different hybrid gear stages are available for the combustion engine 16.

[0075] If only the fifth switching element E is closed, the hybrid transmission 18 can be driven purely electrically, since the first electric drive motor 14 is directly connected to the output 30.

[0076] If only the fourth shift element D is closed, an electrodynamic superposition state, a so-called EDA state, occurs at the planetary gear set RS. The internal combustion engine 16 is then connected to the ring gear of the planetary gear set RS via the first spur gear pair ST1, with the first electric drive motor 14 supporting the torque of the internal combustion engine 16 on the sun gear of the planetary gear set RS. The planetary gear carrier is connected to the output 30, in particular the output shaft 28, via the fourth shift element D. In this shift state, electrodynamic forward starting, EDA starting, is possible.

[0077] From this switching state, the first variant of the first hybrid gear stage H1.1, the third variant of the first hybrid gear stage H1.3, the second variant of the second hybrid gear stage H2.2 and the second variant of the third hybrid gear stage H3.2 can be engaged for the internal combustion engine 16 because the fourth switching element D is closed in each of these switching states.

[0078] An electromechanical powershift from the first gear to the second gear can be performed with output support by the first electric drive motor 14, with the fifth shifting element E remaining closed. This involves changing from the first variant of the first hybrid gear H1.1 to the first variant of the second hybrid gear H2.1. An electromechanical powershift from the second gear to the third gear can also be performed with output support by the first electric drive motor 14, with the fifth shifting element E remaining closed. The vehicle then changes from the first variant of the second hybrid gear H2.1 to the first variant of the third hybrid gear H3.1.

[0079] An electromechanical or electrodynamic load shift from the first variant of the first hybrid gear stage H1.1 to the first variant of the second hybrid gear stage H2.1 in hybrid operation can, for example, occur as follows. In the initial state, i.e. when the first variant of the first hybrid gear stage H1.1 is engaged, the fourth shift element D and the fifth shift element E are closed. This results in a load reduction at the fourth shift element D and a simultaneous load build-up at the first electric drive motor 14. The fourth shift element D is then opened. The speed of the combustion engine 16 is reduced so that the first shift element A becomes synchronous. For this purpose, the combustion engine 16 can, for example, go into overrun mode or, preferably, operate another electric machine in generator mode. The first shift element A can be engaged. During this shifting process, the fifth shift element E remains closed.

[0080] If only the third switching element C is closed, the first electric drive motor 14 can be connected to the internal combustion engine 16 independently of the output 30. The first electric drive motor 14 and the internal combustion engine 16 then rotate in a fixed relationship to one another. This allows, on the one hand, the internal combustion engine 16 to be started by means of the first electric drive motor 14; on the other hand, the first electric drive motor 14 can be operated as a generator by the internal combustion engine 16 and charge the electrical energy storage device 22 or supply other electrical consumers.

[0081] It is understood that a consumer may also use the second electric drive machine 20, as shown for example in Fig. 1, which is arranged on the other vehicle axle and forms a so-called electric rear axle.

[0082] A transition from the charge-to-neutral LiN state is possible to the second variant of the first hybrid gear stage H1.2, the third variant of the first hybrid gear stage H1.3, the third variant of the second hybrid gear stage H2.3 or the third variant of the third hybrid gear stage H3.3 because the third switching element C is closed in each of these switching states.

[0083] If a second electric drive machine 20 is present in the motor vehicle drive train 12, as for example in Fig. As shown in Figure 1, an all-wheel drive system can be created in this combination. For example, a DHT, i.e., a Dedicated Hybrid Transmission, can be designed as a pure front-wheel drive using the internal combustion engine 16 and the first electric drive motor 14, with additional rear-axle drive provided by the second electric drive motor 20. In this range, the electrodynamic superposition state, i.e., the EDA mode, is a power-split E-CVT driving range for the internal combustion engine 16, in which battery-neutral operation is also possible. The term "CVT" is understood, in particular, to mean a continuously variable transmission.

[0084] In particular, traction assistance can be provided by the second electric drive motor 20. The second electric drive motor 20 can support the traction when shifts are necessary in the hybrid transmission 18, during which the output 30 of the hybrid transmission 18 becomes load-free. Such a transition can be carried out, for example, if the vehicle is initially driven purely electrically by the first electric drive motor 14 and / or the second electric drive motor 20 and then the combustion engine 16 is to be started in neutral by the first electric drive motor 14.

[0085] In Fig. 4 shows a further variant of a hybrid transmission 18 according to the invention. In contrast to the Fig. 2, individual transmission components are arranged alternatively with regard to their geometric arrangement in the transmission. Thus, viewed from a connection side of the combustion engine 16 (not shown), first the third spur gear pair ST3, then the double shifting element comprising the second shifting element B and the first shifting element A, then the second spur gear pair ST2, then the fourth shifting element D, then the first spur gear pair ST1, then the planetary gear set RS and finally a double shifting element comprising the third shifting element C and the fifth shifting element E are arranged in the transmission. Furthermore, in contrast to the embodiment shown in Fig. 2, the output shaft 28 is designed as a solid shaft and the second transmission input shaft 26 as a hollow shaft. The second transmission input shaft 26 surrounds the output shaft 28 at least in sections. However, the connections between the individual transmission components are identical to the Fig. 2 shown embodiment.

[0086] Furthermore, the connecting gearwheel, which is arranged on the second transmission input shaft 26 for connecting the first electric drive motor 14, has a passage for the double switching element comprising the third switching element C and the fifth switching element E.

[0087] In Fig. 5 shows a further variant of a hybrid transmission 18 according to the invention. In contrast to the Fig. In the embodiment shown in Figure 2, the fixed and idler gear connections of the second spur gear pair ST2 and the third spur gear pair ST3 are interchanged. Consequently, the first transmission input shaft 24 is designed without a shifting element and has only fixed gears. The double shifting element comprising the first shifting element A and the second shifting element B is arranged on the output shaft 28 and is designed to drive-connect the respective idler gear of the second spur gear pair ST2 or third spur gear pair ST3 to the output shaft 28.

[0088] In Fig. 6 shows a further variant of a hybrid transmission 18 according to the invention. In contrast to the Fig. In the embodiment shown in Figure 2, the second spur gear pair ST2 and the third spur gear pair ST3 are interchanged with respect to their axial position in the hybrid transmission 18. It is understood that the associated shifting elements, i.e., the first shifting element A and the second shifting element B, are interchanged analogously with the associated idler gears of the second spur gear pair ST2 and the third spur gear pair ST3. Consequently, the transmission has a double shifting element comprising the second shifting element B and the first shifting element A.

[0089] As seen from a connection side of the combustion engine 16 (not shown), the hybrid transmission therefore initially comprises the first spur gear pair ST1, then the planetary gear set RS, then the double shifting element comprising the third shifting element C and the fourth shifting element D, then the third spur gear pair ST3, then the double shifting element comprising the second shifting element B and the first shifting element A, then the second spur gear pair ST2, the output gear, then the fourth shifting element E and finally the connection gear for connecting the first electric drive machine 14 in the hybrid transmission 18.

[0090] In Fig. 7 shows a further variant of a hybrid transmission 18 according to the invention. In contrast to the Fig. The embodiment shown in Figure 2 is Fig. In the embodiment shown in Figure 7, the connection to the planetary gear set RS is swapped. In particular, the connections to the ring gear and sun gear of the planetary gear set RS are swapped, with the planetary gear carrier being connectable to the output shaft 28. Consequently, the first electric drive motor 14 is drive-effectively connected to the ring gear of the planetary gear set RS via the second transmission input shaft 26, with the internal combustion engine 16 being drive-effectively connected to the sun gear of the planetary gear set RS via the first spur gear pair ST1.

[0091] Preferably at the Fig. 7 is that the first electric drive motor 14 on the ring gear of the planetary gear set can be operated at a lower compensating speed during electrodynamic starting or electrodynamic shifting. In this case, the first electric drive motor 14 must apply a higher support torque during electrodynamic starting and electrodynamic shifting. Furthermore, the first electric drive motor 14 can be operated as a generator for a shorter period in the electrodynamic superposition state or during electrodynamic starting, since generator operation is abandoned sooner with increasing travel speed than when the first electric drive motor 14 is connected to the sun gear of the planetary gear set RS.

[0092] In Fig. 8 shows a further variant of a hybrid transmission 18 according to the invention. The hybrid transmission 18 according to the Fig. 8 essentially corresponds to the Fig. 2 shown hybrid transmission 18, wherein in Fig. 8, the output 30 is shown in more detail. The output 30 is formed by an output gear arranged between the second spur gear pair ST2 and the third spur gear pair ST3 on the output shaft 28. This output gear meshes with a fixed gear arranged on a differential and thus transmits drive power from the hybrid transmission 18 to the differential. The differential further has a differential shaft 38 that penetrates a rotor shaft of the first electric drive motor 14. In other words, the first electric drive motor 14 can be mounted on the differential shaft 38.

[0093] Furthermore, the hybrid transmission 18 has a transmission input shaft 34, which is arranged axially parallel to the first transmission input shaft 24 and is drivingly connected to the first transmission input shaft 24 via a traction mechanism with a fixed gear arranged between the first spur gear pair ST1 and the second spur gear pair ST2. The transmission input shaft 34 is connected to the internal combustion engine 16 via a torsional vibration damper or another element known in principle in the prior art for torsional vibration decoupling. Furthermore, a fixed gear for connecting a further electric machine 36 is arranged on the transmission input shaft 34. The further electric machine 36 is operatively connected to the transmission input shaft 34 via a traction mechanism. The further electric machine 36 can particularly preferably be designed as a high-voltage starter generator.

[0094] It is understood that the connection of the transmission drive shaft 34 to both the first transmission input shaft 24 and the further electric machine 36 can alternatively also be designed as a gear chain.

[0095] In Fig. 9 shows a further variant of a hybrid transmission 18 according to the invention. In contrast to the Fig. In the embodiment shown in Figure 8, the transmission input shaft 34 comprises an internal combustion engine clutch K0. The internal combustion engine clutch K0 is designed to detachably drive-connect the transmission input shaft 34 to the internal combustion engine 16. The internal combustion engine clutch K0 is arranged between the torsional vibration decoupling element and the two connecting gears of the transmission input shaft 34, so that the additional electric machine 36 is always in drive connection with the first transmission input shaft 24.

[0096] In the Fig. In the example shown in Figure 9, the combustion engine clutch K0 is designed as a positive-locking switching element, for example as a claw clutch.

[0097] In Fig. 10 shows a further variant of a hybrid transmission 18 according to the invention. In contrast to the Fig. In the embodiment shown in Figure 9, the combustion engine clutch K0 is designed as a frictional switching element.

[0098] It is understood that the motor vehicle drive train 12 or the hybrid transmission 18 can also be operated without an internal combustion engine clutch K0. Nevertheless, an internal combustion engine clutch K0 can be useful for various reasons, such as functional safety. In particular, an internal combustion engine clutch K0 in the form of a friction-engaging switching element, as shown in Fig.10, a tow start of the internal combustion engine 16. In particular, in an embodiment with an additional electric machine 36, an internal combustion engine clutch K0 is useful.

[0099] The invention has been comprehensively described and explained with reference to the drawings and the description. The description and explanation are to be understood as exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Other embodiments or variations will become apparent to those skilled in the art upon use of the present invention and upon careful analysis of the drawings, the disclosure, and the following claims.

[0100] In the patent claims, the words "comprising" and "having" do not exclude the presence of further elements or steps. The undefined article "a" or "an" does not exclude the presence of a plurality. A single element or a single unit can perform the functions of several of the units recited in the patent claims. The mere mention of some measures in several different dependent patent claims should not be understood to mean that a combination of these measures cannot also be used advantageously. Reference symbols in the patent claims are not to be understood as limiting. A method for operating a motor vehicle drivetrain 12 can, for example, be implemented in the form of a computer program that is executed on a control unit for the motor vehicle drivetrain 12.A computer program may be stored / distributed on a non-volatile storage medium, such as optical storage or a solid-state drive (SSD). A computer program may be distributed together with hardware and / or as part of hardware, such as via the Internet or via wired or wireless communication systems. Reference symbol 10 motor vehicle 12 Automotive powertrain 14 first electric drive machine 16 Combustion engine 18 hybrid transmissions 20 second electric drive motor 22 energy storage 24 first transmission input shaft 26 second transmission input shaft 28 Output shaft 30 downforce 32 switching matrix 34 Gearbox drive shaft 36 additional electric machines 38 Differential shaft A to E switching elements K0 internal combustion engine clutch ST1 - ST3 spur gear pairs

Claims

[1] Hybrid transmission (18) for a motor vehicle drive train (12) of a motor vehicle (10), comprising: a first transmission input shaft (24) for operatively connecting the hybrid transmission to an internal combustion engine (16) of the motor vehicle; a second transmission input shaft (26) for operatively connecting the hybrid transmission (18) to a first electric drive motor (14) of the motor vehicle; an output shaft (28) for operatively connecting the hybrid transmission (18) to an output (30); a planetary gear set (RS) which is drivingly connected to the first transmission input shaft (24) and the second transmission input shaft (26); spur gear pairs (ST1, ST2, ST3) arranged in several gear set levels to form gear steps; and several gearshift devices with shift elements (A, B, C, D, E) for engaging gear steps, wherein a first spur gear pair (ST1) of the spur gear pairs (ST1, ST2, ST3) is assigned to the first transmission input shaft (24) to form gear stages; a second spur gear pair (ST2) and a third spur gear pair (ST3) of the spur gear pairs (ST1, ST2, ST3) are assigned to the first transmission input shaft (24) and the output shaft (28) to form gear stages; the output shaft (28) is designed as a hollow shaft and surrounds the second transmission input shaft (26) designed as a solid shaft at least in sections to enable a connection to a differential of the output (30) in a transmission center; or wherein the second transmission input shaft (26) is designed as a hollow shaft and surrounds the output shaft (28) designed as a solid shaft at least in sections in order to enable a connection to a differential of the output (30) on an outer side of the transmission. [2] Hybrid transmission (18) according to claim 1, wherein the first electric drive machine (14) is connected to the hybrid transmission (18) on a transmission side which is opposite a connection side of the internal combustion engine (16); starting from a connection side of the internal combustion engine (16), the third spur gear pair (ST3), the second spur gear pair (ST2), the first spur gear pair (ST1) and the planetary gear set (RS) are arranged in this order; or starting from the connection side of the combustion engine (16), the first spur gear pair (ST1), the planetary gear set (RS), the second spur gear pair (ST2) and the third spur gear pair (ST3) are arranged in this order. [3] Hybrid transmission (18) according to claim 1 or 2, wherein in two of the spur gear pairs (ST1, ST2, ST3) for forming the gear stages, an arrangement of the loose gear is interchangeable with the arrangement of the fixed gear; an axial arrangement of two of the spur gear pairs (ST1, ST2, ST3) is interchangeable to form the gear stages; and / or the first transmission input shaft (24) is designed without a switching element. [4] Hybrid transmission (18) according to one of the preceding claims, wherein the hybrid transmission (18) has a transmission input shaft (34) which is drivingly connected to the first transmission input shaft (24) and is arranged axially parallel to the first transmission input shaft (24), and / or the output shaft (28) is drivingly connected to a differential of the output (30), wherein the differential comprises a differential shaft (38) for transmitting drive power from the hybrid transmission (18) to the wheels of the motor vehicle (10), which is arranged axially parallel to the output shaft (28) and is designed to penetrate the first electric drive machine (14) in order to enable the first electric drive machine (14) to be arranged around the differential shaft (38). [5] Hybrid transmission (18) according to one of the preceding claims, wherein a planetary gear carrier of the planetary gear set (RS) can be connected to the output shaft (28) in a drive-effective manner; the sun gear of the planetary gear set (RS) is connected to the first transmission input shaft (24) by means of the first spur gear pair (ST1) of the spur gear pairs (ST1, ST2, ST3) to form the gear stages, and the ring gear of the planetary gear set (RS) is drivingly connected to the second transmission input shaft (26); or the ring gear of the planetary gear set (RS) is connected to the first transmission input shaft (24) by means of the first spur gear pair (ST1) of the spur gear pairs (ST1, ST2, ST3) to form the gear stages, and the sun gear of the planetary gear set (RS) is drivingly connected to the second transmission input shaft (26). [6] Hybrid transmission (18) according to one of the preceding claims, with an internal combustion engine clutch (K0) for the releasable, drive-effective connection of the first transmission input shaft (24) to the internal combustion engine (16), wherein the internal combustion engine clutch (K0) is preferably arranged on the transmission input shaft (34). [7] Hybrid transmission (18) according to one of the preceding claims, wherein a first shift element (A) is designed to drive-effectively connect the first transmission input shaft (24) to the output shaft (28) by means of the second spur gear pair (ST2) of the spur gear pairs (ST1, ST2, ST3) to form gear stages; a second shift element (B) is designed to drive-effectively connect the first transmission input shaft (24) to the output shaft (28) by means of the third spur gear pair (ST3) of the spur gear pairs (ST1, ST2, ST3) to form gear stages; a third shifting element (C) is designed to block the planetary gear set (RS); a fourth shift element (D) is designed to drive-effectively connect the planetary gear set (RS) to the output shaft (28); and / or a fifth switching element (E) is designed to drive-effectively connect the second transmission input shaft (26) to the output shaft (28). [8] Hybrid transmission (18) according to one of the preceding claims, wherein the hybrid transmission (18) has exactly three spur gear pairs (ST1, ST2, ST3), exactly one planetary gear set (RS) and exactly five shift elements (A, B, C, D, E) for forming three hybrid gear stages. [9] Hybrid transmission (18) according to one of the preceding claims, wherein the switching elements (A, B, C, D, E) are designed as positive-locking switching elements; and / or at least two of the switching elements (A, B, C, D, E), preferably four switching elements, are designed as double switching elements and can be actuated by a double-acting actuator. [10] Motor vehicle drive train (12) for a motor vehicle (10), comprising: a hybrid transmission (18) according to one of the preceding claims; an internal combustion engine (16) connectable to the first transmission input shaft (24); and a first electric drive motor (14) which is drivingly connected to the second transmission input shaft (26). [11] Motor vehicle drive train (12) according to claim 10, wherein the motor vehicle drive train (12) preferably comprises a further electric machine (36) which is drivingly connected to the first transmission input shaft (24) and the first electric drive machine (14) and / or preferably the further electric machine (36) can be controlled as a starter generator for starting the internal combustion engine (16); and / or can be controlled as a charging generator for charging an energy storage device (22). [12] Motor vehicle drive train (12) according to claim 10 or 11, wherein the output (30) of the hybrid transmission (18) is driveably connectable to a first motor vehicle axle and a second motor vehicle axle comprises an electric axle with a second electric drive motor (20); and preferably the first electric drive machine (14) and / or the further electric machine (36) can be controlled as a generator for supplying the second electric drive machine (20) in order to establish a serial driving mode. [13] Method for operating a motor vehicle drive train (12) according to one of claims 10 to 12. [14] Motor vehicle (10) with: a motor vehicle drive train (12) according to one of claims 10 to 12; and an energy storage device (22) for storing energy to supply the first electric drive machine (14); a second electric drive machine (20) and / or a further electric machine (36).

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