Compact hybrid transmission

Abstract

Hybrid transmission (20) for a motor vehicle powertrain (12) of a motor vehicle (10), comprising: a first transmission input shaft (24) for connecting the hybrid transmission (20) with an internal combustion engine (16) and a second electric drive motor (18) of the motor vehicle (10); a second transmission input shaft (26) for connecting the hybrid transmission (20) with a first electric drive motor (14) of the motor vehicle (10); a planetary gear set (RS) with a first planetary gear set element, a second planetary gear set element and a third planetary gear set element; a countershaft (28); Spur gear pairs (ST1, ST2, ST3, ST4) arranged in several gear set planes to form gear steps; and several gearshift devices with shifting elements (A, B, C, D, E, F) for engaging gear stages, wherein the first spur gear pair (ST1), the second spur gear pair (ST2) and the third spur gear pair (ST3) of the spur gear pairs (ST1, ST2, ST3, ST4) are assigned to form gear stages of the countershaft (28) and the first transmission input shaft (24); the fourth spur gear pair (ST4) of the spur gear pairs (ST1, ST2, ST3, ST4) is assigned to form gear stages of the first transmission input shaft (24), the second transmission input shaft (26) and the countershaft (28); and The first electric drive motor (14) can be decoupled in a variant of each hybrid gear stage (H1.3, H2.3, H3.3, H4.3) to enable efficient driving operation using the combustion engine (16) and / or the second electric drive motor (18).

Description

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

[0002] Vehicles are increasingly being equipped with hybrid drives, meaning they have at least two different drive sources. Hybrid drives can contribute to reducing fuel consumption and pollutant emissions. Powertrains with an internal combustion engine and one or more electric motors, either as parallel hybrids or mixed hybrids, have largely become the standard. In such hybrid drives, the internal combustion engine and the electric motor are arranged in a largely parallel power flow. This allows for both a superposition of the drive torques and control using either the internal combustion engine or the electric motor. Since the drive torques of the electric motor and the internal combustion engine can add up depending on the control configuration, a comparatively smaller internal combustion engine and / or its temporary deactivation are possible.This allows for a significant reduction in CO2 emissions without any noticeable 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] One disadvantage of the aforementioned hybrid drives is their generally more complex design, as both drive sources preferably transmit power to a single drive shaft via a single hybrid transmission. This makes such hybrid transmissions typically complex and expensive to produce. Reducing the complexity of a hybrid transmission's design usually comes at the cost of reduced versatility.

[0004] This disadvantage can be at least partially overcome by means of dedicated hybrid transmissions (DHTs), in which an electric motor is integrated into the hybrid transmission to provide the full range of functions. For example, the mechanical transmission component of the hybrid transmission can be simplified, such as by eliminating the reverse gear, with at least one electric motor used 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 then becomes part of the transmission.

[0006] German patent application DE 10 2020 205 090 A1 discloses a transmission for a motor vehicle, comprising: a first drive shaft for a first drive unit, a second drive shaft for a second drive unit, and an output shaft. The transmission includes a sub-transmission comprising the first drive shaft and a countershaft coupled to the first drive shaft via a constant gear ratio. Gears are arranged on the countershaft, meshing exclusively with gears arranged coaxially to the first drive shaft. At least some of these gears mesh with gears arranged on the output shaft. Both the first drive shaft and the countershaft are equipped with shift elements that provide either a gear with a first number of gear engagements or a winding gear with a second number of gear engagements. The transmission further comprises a second sub-transmission comprising the second drive shaft.The second sub-gearbox is designed as a planetary gearbox, wherein a ring gear forms the second drive shaft of the second sub-gearbox, wherein a bridge is permanently coupled to the output shaft and to a gear arranged on the countershaft, wherein switching elements are assigned to the planetary gearbox, via which, depending on their switching position, a sun gear can be fixed to the housing or the planetary gearbox can be brought into block rotation.

[0007] Other hybrid transmissions are known, for example, from the patent applications DE 10 2020 205 099 A1 and DE 10 2014 213 607 A1.

[0008] Against this background, a specialist faces the task of creating a compact hybrid transmission. The hybrid transmission should be radially compact and preferably have four hybrid and two electric gear ratios.

[0009] This task is solved by a hybrid transmission for a motor vehicle powertrain, comprising: a first transmission input shaft for connecting the hybrid transmission to an internal combustion engine and a second electric drive motor of the motor vehicle; a second transmission input shaft for connecting the hybrid transmission to a first electric drive motor of the motor vehicle; a planetary gear set with a first planetary gear set element, a second planetary gear set element and a third planetary gear set element; a countershaft; Spur gear pairs arranged in several gear set planes to form gear stages; and several gearshift devices with switching elements for engaging gear stages, wherein the first spur gear pair, the second spur gear pair and the third spur gear pair of the spur gear pairs are assigned to form gear stages of the countershaft and the first transmission input shaft; the fourth spur gear pair of the spur gear pairs is assigned to form gear stages of the first transmission input shaft, the second transmission input shaft and the countershaft; and The first electric drive motor can be decoupled in one variant of each hybrid gear stage to enable efficient driving operation using the combustion engine and / or the second electric drive motor.

[0010] The above problem is further solved by a motor vehicle powertrain for a motor vehicle with a hybrid transmission as defined above; with: an internal combustion engine that can be connected to the first transmission input shaft; a first electric drive motor connected to the second gearbox input shaft; and a second electric drive motor, which is effectively connected to the first gearbox input shaft.

[0011] The above problem is also solved by a method for operating a motor vehicle powertrain as defined above.

[0012] The above task is ultimately solved by a motor vehicle equipped with: a motor vehicle powertrain as previously defined; and an energy storage system for storing energy to supply the electric drive motors.

[0013] 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 combinations specified, but also in other combinations or individually, without departing from the scope of the present invention. In particular, the motor vehicle powertrain, the method, and the motor vehicle can be configured according to the embodiments described for the hybrid transmission in the dependent claims.

[0014] A compact hybrid transmission can be easily created by means of a first transmission input shaft for connecting the hybrid transmission to an internal combustion engine and a second electric drive motor, as well as a second transmission input shaft for connecting the hybrid transmission to a first electric drive motor. The connection can be either switchable or non-switchable. In particular, a hybrid transmission can be designed for a front-transverse arrangement in a motor vehicle powertrain, wherein an electric axle can preferably be arranged on the axle of the motor vehicle not connected to the hybrid transmission. A planetary gear set enables a compact hybrid transmission with which, in particular, two pure electric gear stages can be configured. Furthermore, the two electric gear stages can advantageously be combined with up to four gear stages for the internal combustion engine to form hybrid gear stages.It is understood that each gear stage for an internal combustion engine in this case can also be considered a hybrid gear stage, since the second electric drive motor is preferably operatively connected or operatively connectable to the internal combustion engine via the first transmission input shaft. By assigning the first, second, and third spur gear pairs to the layshaft and the first transmission input shaft for forming gear stages, a radially compact hybrid transmission can be created. The assignment of a spur gear pair to a transmission component or to a transmission shaft can be understood, in particular, to mean that the transmission shafts assigned to the spur gear pair can be effectively connected to each other via the spur gear pair.By assigning the fourth spur gear pair to the first transmission input shaft, the second transmission input shaft, and the layshaft, a weight-optimized, compact hybrid transmission can be created, as no additional gear is required to combine the electric gear stages with the mechanical gear stages for the combustion engine. The hybrid transmission exhibits low component stress, low transmission losses, and good gear efficiency in both combustion engine and purely electric modes. Despite its compact design, all switching elements of the hybrid transmission are easily accessible via actuators.

[0015] In an advantageous embodiment, the planetary gear set has a first connection to the fourth spur gear pair, a second connection to a housing, and a third connection to the first electric drive motor. Additionally, two of the aforementioned connections are designed as permanent connections, one of which is designed as a switchable connection. This allows for the creation of a hybrid transmission that is flexible with respect to the available installation space, since the aforementioned various embodiments can be switched with the same effect, but allow for a high degree of flexibility in the arrangement of the planetary gear set and, in particular, the switching elements for switching the planetary gear set.Particularly preferred is a ring gear of the planetary gear set connected or connectable to the fourth spur gear pair, a planet carrier of the planetary gear set connected or connectable to the second transmission input shaft, and a sun gear of the planetary gear set fixed or fixable.

[0016] In a further advantageous embodiment, the switching elements are designed as positive-locking switching elements, and in particular as claw switching elements. Additionally or alternatively, at least two of the switching elements, preferably all switching elements, are designed as double switching elements and can be actuated by a double-acting actuator. Positive-locking switching elements enable a highly efficient and cost-effective hybrid transmission. The technical design of the hybrid transmission can be further simplified by using a double switching element. A double switching element can be switched by means of a single actuator, thereby reducing the wiring and control effort.

[0017] In a further advantageous embodiment, the second transmission input shaft is designed as a hollow shaft and surrounds the first transmission input shaft, at least partially. Additionally or alternatively, the first and second transmission input shafts are arranged parallel to the countershaft. This further improves the compactness of the hybrid transmission.

[0018] In a further advantageous embodiment, the hybrid transmission features an internal combustion engine clutch for the detachable, drive-effective connection of the first transmission input shaft to the internal combustion engine. It is understood that the internal combustion engine clutch can be designed as a dog clutch or a friction clutch. An internal combustion engine clutch allows the internal combustion engine to be decoupled from the hybrid transmission, thus enabling a highly efficient, purely electric driving mode via the hybrid transmission. A friction clutch also allows for a so-called momentum start of the internal combustion engine and can serve as a starting element for the internal combustion engine. An internal combustion engine clutch increases the variability and efficiency of the hybrid transmission.

[0019] The first electric drive motor can be decoupled in one variant of each hybrid gear stage to enable efficient driving operation using the combustion engine and / or the second electric drive motor. This prevents the first electric drive motor from being unnecessarily dragged along during combustion engine operation. Furthermore, a purely electric driving mode can be established, in which support power can be provided by either the first or second electric drive motor when switching between them.

[0020] In a further advantageous embodiment, the hybrid transmission comprises exactly four spur gear pairs, exactly one planetary gear set, and exactly six shift elements for forming four hybrid gear stages and two electric gear stages. Additionally or alternatively, with three spur gear pairs forming the gear stages, the arrangement of the loose gear and the fixed gear can be interchanged. Furthermore, additionally or alternatively, an axial arrangement of three of the spur gear pairs for forming the gear stages can be freely interchanged. This allows for the creation of a transmission with a technically simple design and, in particular, a comparatively small number of components. The interchangeability of a loose gear with a fixed gear, or the interchangeability of an axial arrangement of the spur gear pairs, enables a highly variable transmission that can be advantageously adapted to different installation space requirements without sacrificing functionality.

[0021] In a further advantageous embodiment, the hybrid transmission can be connected to the internal combustion engine at a first transmission input, and to the first electric drive motor at a second transmission input opposite the first. Additionally or alternatively, the hybrid transmission can be connected to the second electric drive motor at the first transmission input by means of a spur gear pair to form gear stages or a connecting gear. The advantageous opposite arrangement of the first electric drive motor and the internal combustion engine further increases the radial compactness of the hybrid transmission or the drivetrain with such a hybrid transmission.Connecting the second electric drive motor via a spur gear pair enables a weight-optimized and component-saving connection to the hybrid transmission. Connecting the second electric drive motor via a connecting gear allows for a wider selection of its size, power output, and gear ratio. This enables the creation of a flexible hybrid powertrain tailored to a specific application.

[0022] In a further advantageous embodiment, a first switching element is configured to effectively connect the first transmission input shaft to the countershaft via the fourth spur gear pair. Additionally or alternatively, a second switching element is configured to effectively connect the first transmission input shaft to the countershaft via the second spur gear pair. Furthermore, additionally or alternatively, a third switching element is configured to effectively connect the first transmission input shaft to the countershaft via the third spur gear pair. Additionally or alternatively, a fourth switching element is configured to effectively connect the first transmission input shaft to the countershaft via the first spur gear pair.Furthermore, or alternatively, a fifth switching element is configured to effectively connect the second transmission input shaft to the fourth spur gear pair and, furthermore, to the countershaft via the fourth spur gear pair. Finally, or alternatively, a sixth switching element is configured to effectively connect the second transmission input shaft, via the planetary gear set, to the countershaft via the fourth spur gear pair. This advantageous arrangement of switching elements allows the hybrid transmission to provide four hybrid gear stages with multiple variants, as well as two purely electric gear stages. Furthermore, all gear stages can be configured by engaging a maximum of two switching elements, with the two purely electric gear stages each being configurable by engaging a single switching element.

[0023] In a further advantageous embodiment, a first hybrid gear stage can be set up by closing the first switching element and preferably the fifth or sixth switching element. Additionally or alternatively, a second hybrid gear stage can be set up by closing the second switching element and preferably the fifth or sixth switching element. Furthermore, additionally or alternatively, a third hybrid gear stage can be set up by closing the third switching element and preferably the fifth or sixth switching element. Additionally or alternatively, a fourth hybrid gear stage can be set up by closing the fourth switching element and preferably the fifth or sixth switching element. Furthermore, additionally or alternatively, a first electric gear stage can be set up by closing the fifth switching element.Finally, a second electric drive stage can be additionally or alternatively engaged by closing the sixth switching element. This advantageous gear sequence allows for a first variant and a second variant to be configured for each hybrid drive stage, in which the first electric drive motor is engaged in either the first pure electric drive stage or the second pure electric drive stage to form the corresponding hybrid drive stage. Furthermore, a hybrid drive stage decoupled from the first electric drive motor can be configured, in which operation preferably occurs only via the combustion engine and / or the second electric drive motor.

[0024] In a preferred embodiment, the second electric drive motor can be controlled as a starter-generator to start the internal combustion engine. Additionally or alternatively, the second electric drive motor can be operated as a generator by the internal combustion engine to provide energy for series creep using the first electric drive motor. This eliminates the need for an external starter for the internal combustion engine. The vehicle powertrain can be designed with optimized weight. Furthermore, purely electric driving using the first electric drive motor is possible even when the energy storage system is depleted.

[0025] In a further advantageous embodiment, the first electric drive motor is designed as a coaxial motor, and the planetary gear set and / or a double switching element are arranged at least partially radially and / or axially within the first electric drive motor. This allows for the creation of a radially compact vehicle powertrain. In particular, the first electric drive motor can be directly connected to the hybrid transmission, thus eliminating the need for additional components such as a gear chain, a traction drive, or further shafts. The hybrid transmission can be designed with optimized weight.

[0026] Locking an element of a planetary gear set is understood in particular as blocking the element's rotation about its axis of rotation. Preferably, the element is connected to a static component, such as a frame and / or a gearbox housing, in a rotationally fixed manner by means of a locking element. It is also conceivable to brake the element until it comes to a standstill.

[0027] A planetary gear set is locked together by connecting two gears and / or the planet carrier and a gear of the planetary gear set in a way that provides a driving force, so that they rotate together at the same speed around the same point, preferably the center of the planetary gear set. When two gears and / or a planet carrier and a gear of the planetary gear set are locked together, the planetary gear set preferably acts like a shaft; in particular, no gear ratio is achieved within the planetary gear set.

[0028] In this context, "drive-effectively connected" or "connected" refers specifically to a non-switchable connection between two components, intended for the permanent transmission of rotational speed, torque, and / or drive power. This connection can be direct or via a fixed gear ratio. The connection can be made, for example, via a fixed shaft, a gear, particularly a spur gear, and / or a drive element, particularly a traction drive.

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

[0030] Stationary charging or charging-in-neutral refers in particular to operating the electric drive motor as a generator, preferably when stationary with the combustion engine running, in order to charge an energy storage device and / or to power on-board electronics.

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

[0032] A gear change, particularly a series shift, is achieved by disengaging a shift element and / or clutch and simultaneously engaging the shift element and / or clutch for the next higher or lower gear. The second shift element and / or clutch thus gradually takes over the torque from the first shift element and / or clutch until, at the end of the gear change, the entire torque is being handled by the second shift element and / or clutch. With prior synchronization, a gear change can be performed more quickly; preferably, positive-locking shift elements can be used for this purpose.

[0033] An internal combustion engine can be any machine that can generate rotary motion by burning a fuel such as gasoline, diesel, kerosene, ethanol, liquefied petroleum gas (LPG), or autogas. Examples of internal combustion engines include gasoline engines, diesel engines, Wankel engines, and two-stroke engines.

[0034] In serial driving or creep mode, an electric motor of a vehicle is driven as a generator by an internal combustion engine of the same vehicle. The energy generated in this way is then supplied to another electric motor of the vehicle to provide propulsion power.

[0035] An electric vehicle axle, or simply electric axle, is preferably a non-main drive axle of a motor vehicle, in which drive power can be transmitted 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 maintained wholly or partially by means of an electric axle when a gear change occurs in the transmission for a main drive axle. Furthermore, an all-wheel-drive functionality can be implemented, at least partially, by means of an electric axle.

[0036] An electrodynamic starting element (EDA) uses one or more planetary gear sets to superimpose the speeds of the combustion engine and the electric drive motor, enabling a vehicle to start from a standstill with the combustion engine running, preferably without a friction clutch. The electric drive motor provides torque support. Preferably, the combustion engine can no longer be disconnected from the transmission by a starting clutch or similar device. Using an EDA preferably eliminates the need for a starter, generator, and starting clutch or hydrodynamic torque converter. In particular, an EDA is designed to be so compact that all components fit within the standard clutch housing without extending the transmission.The electrodynamic starting element can be rigidly connected to an internal combustion engine, and in particular to the flywheel of an internal combustion engine, via a softly tuned torsional damper. This allows the electric drive and the internal combustion engine to be operated either simultaneously or alternatively. When the vehicle comes to a stop, both the electric drive and the internal combustion engine can be switched off. Due to the precise controllability of the electric drive, a very high level of starting performance is achieved, comparable to that of a drive with a torque converter.

[0037] In a so-called electrodynamic shift (EDS), as with EDA starting, the speeds of the combustion engine and the electric drive motor are 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 engaged is unloaded. After this shift element opens, the speed is adjusted while maintaining the tractive force, so that the shift element to be engaged becomes synchronous. After the shift element closes, the load distribution between the combustion engine and the electric drive motor occurs as desired, depending on the hybrid operating strategy.The electrodynamic shifting method has the advantage that the shift element to be selected for the target gear is synchronized by 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 EDS shifting method is that high tractive force can be achieved, since the torques of the combustion engine and the electric motor combine in the hybrid transmission.

[0038] The invention is described and explained in more detail below with reference to some selected embodiments in conjunction with the accompanying drawings. These show: Fig. 1 a schematic top 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. Schematic representation of 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. Figure 1 schematically shows a motor vehicle 10 with a motor vehicle drivetrain 12. The motor vehicle drivetrain 12 comprises a first electric drive motor 14, an internal combustion engine 16, and a second electric drive motor 18, which are connected to a front axle of the motor vehicle 10 by means of a hybrid transmission 20. It is understood that a connection to a rear axle of the motor vehicle 10 is also possible. The motor vehicle drivetrain 12 supplies drive power from the internal combustion engine 16, the first electric drive motor 14, and / or the second electric drive motor 18 to the wheels of the motor vehicle 10. The motor vehicle 10 also has an energy storage device 22 to store energy that serves to supply the first and second electric drive motors 14 and 18.It is understood that the motor vehicle powertrain 12 may also include an electric axle which drives the axle of the motor vehicle 10 that is not connected to the hybrid transmission 20.

[0040] Fig. Figure 2 shows a simplified version of a hybrid transmission 20 according to the invention in a motor vehicle powertrain 12. The hybrid transmission 20 comprises a first transmission input shaft 24 and a second transmission input shaft 26, which are designed to transmit drive power from the drive motors 14, 16, 18 into the hybrid transmission 20.

[0041] The first transmission input shaft 24 is designed as a solid shaft and is arranged coaxially to the second transmission input shaft 26. The second transmission input shaft 26 surrounds the first transmission input shaft 24, at least partially.

[0042] The hybrid transmission further comprises a total of four gear-forming spur gear pairs, designated ST1-ST4, as well as a planetary gear set RS and a countershaft 28. In the example shown, the countershaft 28 functions as an output shaft and is connected to an output 30 of the hybrid transmission 20 via an output gear not specified in more detail.

[0043] A sun gear of the planetary gear set RS is fixed, a planet carrier of the planetary gear set RS is effectively connected to the second transmission input shaft 26, and a ring gear of the planetary gear set RS can be effectively connected to the fourth spur gear pair ST4. Furthermore, the second transmission input shaft 26 can be connected to the fourth spur gear pair ST4, wherein the second transmission input shaft 26 is effectively connected to the first electric drive machine 14, which is designed as a coaxial machine.

[0044] In the example shown, the second electric drive motor 18 is effectively connected to the first transmission input shaft 24 by means of the first spur gear pair ST1, in particular a fixed gear of the first spur gear pair ST1 arranged on the first transmission input shaft 24. Furthermore, the internal combustion engine 16 (not shown) is connected to the first transmission input shaft 24.

[0045] The first spur gear pair ST1 and the second spur gear pair ST2 each comprise a fixed gear arranged on the first transmission input shaft 24, which meshes with a loose gear arranged on the countershaft 28. The third spur gear pair ST3 and the fourth spur gear pair ST4 each comprise a loose gear arranged on the first transmission input shaft 24, which meshes with a fixed gear arranged on the countershaft 28.

[0046] The loose gear of the fourth spur gear pair ST4 can be effectively connected to the first transmission input shaft 24 by inserting a first switching element A.

[0047] The loose gear of the second spur gear pair ST2 can be effectively connected to the countershaft 28 by inserting a second switching element B.

[0048] The loose gear of the third spur gear pair ST3 can be effectively connected to the first transmission input shaft 24 by inserting a third switching element C.

[0049] The loose gear of the first spur gear pair ST1 can be effectively connected to the countershaft 28 by inserting a fourth switching element D.

[0050] The loose gear of the fourth spur gear pair ST4 can also be connected to the second transmission input shaft 26 by inserting a fifth switching element E, whereby no transmission is provided by the planetary gear set RS in this connection.

[0051] Furthermore, the loose gear of the fourth spur gear pair ST4 can be connected to a ring gear of the planetary gear set RS by inserting a sixth switching element F, whereby this connection provides a reduction or translation of the drive power of the first electric drive machine 14 by means of the planetary gear set RS.

[0052] In the embodiment shown, the planetary gear set RS is arranged at least partially radially and / or axially within the first electric drive motor 14. The second switching element B is combined with the fourth switching element D to form a double switching element. The first switching element A is combined with a third switching element C to form a double switching element. Furthermore, the fifth switching element E and the sixth switching element F are combined to form a double switching element. It is understood that all switching elements can be designed as positive-locking switching elements, for example, claw switching elements.

[0053] In the example shown, the transmission components are arranged as follows, viewed from a connection side of the combustion engine 16 (not shown); first the first spur gear pair ST1, then the double switching element comprising the fourth switching element D and the second switching element B, then the second spur gear pair ST2, then the third spur gear pair ST3, then the double switching element comprising the third switching element C and the first switching element A, then the fourth spur gear pair ST4, then the double switching element comprising the fifth switching element E and the sixth switching element F, and finally the planetary gear set RS.

[0054] It is further understood that a differential is usually connected downstream of the gear set shown in the hybrid transmission 20. Furthermore, an element for torsional vibration decoupling, for example a torsional damper or a dual-mass flywheel, can preferably be arranged between the combustion engine 16 and the first transmission input shaft 24.

[0055] In Fig. Figure 3 schematically represents the switching states of the hybrid transmission 20 according to the Fig. Figure 2 and the following figures are shown in a switching matrix 32. The first column of the switching matrix 32 shows the hybrid gear stages H1 to H4, two electric gear stages E1 and E2, and a charging-to-neutral state. Additionally, the combination of combustion gear stage and electric gear stage that forms the respective hybrid or electric gear stage is indicated for each gear stage. The second to seventh columns show the switching states of the switching elements A to F and an optional combustion engine clutch, as shown, for example, in the Fig. 9 and Fig. Figure 10 shows the following, where an "X" indicates that the respective switching element or clutch is closed, thus effectively connecting the associated transmission components. If no entry is present, it can be assumed that the corresponding switching element is open, i.e., not transmitting any drive power. The hybrid gear stages H1 to H4 each have three variants, with the first column additionally including a combination of the respective combustion gear stage with the respective electric gear stage that results in the respective hybrid gear stage.

[0056] A first variant of the first hybrid gear stage H1.1, which represents a combination of the first combustion gear stage V1 with the first electric gear stage E1, can be set up by closing the combustion engine clutch K0, the first switching element A and the fifth switching element E.

[0057] Closing the combustion engine clutch K0, the first switching element A and the sixth switching element F establishes a second variant of the first hybrid gear stage H1.2, which represents a combination of the first combustion gear stage V1 with the second electric gear stage E2.

[0058] A third variant of the first hybrid gear stage H1.3, which represents a combination of the first combustion gear stage V1 with the zeroth electric gear stage E0, can be engaged by closing the combustion engine clutch K0 and the first switching element A. Electric gear stage E0 specifically means that the first electric drive motor 14 does not transmit any drive power in this gear stage.

[0059] The first variants of the hybrid gear stages are each a combination of the corresponding combustion gear stage with the first electric gear stage E1. The second variants of the hybrid gear stages correspond to a combination of the corresponding combustion gear stage with the second electric gear stage E2. The third variants of the hybrid gear stages each correspond to a combination of the corresponding combustion gear stage with the electric gear stage E0, i.e., a switching state in which the first electric drive motor 14 does not contribute any transmission power.

[0060] A first variant of the second hybrid gear stage H2.1 can be set up by closing the combustion engine clutch K0, the second switching element B and the fifth switching element E.

[0061] Closing the combustion engine clutch K0 of the second switching element B and the sixth switching element F establishes a second variant of the second hybrid gear stage H2.2.

[0062] A third variant of the second hybrid gear stage H2.3 can be set up by closing the combustion engine clutch K0 and the second switching element B.

[0063] Closing the combustion engine clutch K0, the third switching element C and the fifth switching element E establishes a first variant of the third hybrid gear stage H3.1.

[0064] A second variant of the third hybrid gear stage H3.2 can be set up by closing the combustion engine clutch K0, the third switching element C and the sixth switching element F.

[0065] Closing the combustion engine clutch K0 and the third switching element C establishes a third variant of the third hybrid gear stage H3.3.

[0066] A first variant of the fourth hybrid gear stage H4.1 can be set up by closing the combustion engine clutch K0, the fourth switching element D and the fifth switching element E.

[0067] Closing the combustion engine clutch K0, the fourth switching element D and the sixth switching element F establishes a second variant of the fourth hybrid gear stage H4.2.

[0068] A third variant of the fourth hybrid gear stage H4.3 can be set up by closing the combustion engine clutch K0 and the fourth switching element D.

[0069] To set up the first electrical stage E1, the fifth switching element E must be closed.

[0070] The second electrical stage E2 can be set up by closing the sixth switching element F.

[0071] In the switching matrix 32, a combination with the zeroth combustion stage V0 means that no drive power is provided by the combustion engine 16.

[0072] A state of loading-in-neutral using the second electric drive motor 18 can be established by closing the combustion engine clutch K0.

[0073] It goes without saying that if no combustion engine clutch K0 is present, i.e., for example as in the one in Fig. In the hybrid transmission 20 shown, the combustion engine clutch K0 is to be regarded as closed.

[0074] The second electric drive motor 18 enables the combustion engine 16 to be started from purely electric operation. Furthermore, the second electric drive motor 18 can be operated as a generator by the combustion engine 16, thus ensuring an on-board power supply.

[0075] It is understood that the generator-operated second electric drive machine 18 makes serial creeping or driving possible both forwards and backwards, whereby the energy converted by the second electric drive machine 18 into a generator can be made available to the first electric drive machine 14 for the corresponding driving operation.

[0076] Furthermore, the second electric drive motor 18 can assist the combustion engine 16 in speed control, for example during coupling and switching operations.

[0077] The combustion engine 16 can be coupled in all hybrid gear stages if the first electric drive motor 14 uses the first electric gear stage E1 or the second electric gear stage E2. In other words, the combustion engine 16 can be coupled in every hybrid gear stage.

[0078] Furthermore, the second electric drive motor 18 can assist in relieving the load on the first to fourth switching elements A to D by being driven as a generator by the combustion engine 16. The current generated in this way can be used by the first electric drive motor 14 to provide traction assistance.

[0079] The first electric drive motor 14 enables electric starting and driving, both forwards and backwards. Furthermore, the first electric drive motor 14 can support the tractive force during switching operations for the internal combustion engine 16. In particular, the first electric drive motor 14 can maintain the tractive force via the first electric gear stage E1 or the second electric gear stage E2 when a change occurs at a first, second, third, or fourth switching element A, B, C, D.

[0080] A load shift from the first combustion stage V1 to the second combustion stage V2 in hybrid operation can, for example, be carried out as follows. Initially, i.e., when the first combustion stage V1 for the combustion engine 16 is engaged, the first switching element A and – if present – ​​the combustion engine clutch K0 are closed. Subsequently, a load reduction occurs at the first switching element A and a simultaneous load build-up occurs at the first electric drive 14. The load reduction can occur either by the combustion engine 16 and the second electric drive 18 reducing their torque, or by the second electric drive 18 generating a counterbalance to the torque of the combustion engine 16, so that the sum of the torques of the combustion engine 16 and the second electric drive 18 is essentially zero. The first switching element A is then opened.The rotational speeds of the internal combustion engine 16 and the second electric drive motor 18 are reduced so that the second switching element B becomes synchronized. For this purpose, the second electric drive motor 18 can, for example, operate as a generator, which is preferred, or the internal combustion engine 16 can enter overrun mode. The second switching element B can then be engaged.

[0081] In hybrid mode, a load-free switch can be made in the background from the first electric gear stage E1 to the second electric gear stage E2, whereby the switch is made from the first variant of the corresponding hybrid gear stage to the second variant of the corresponding hybrid gear stage. During this process, the speed of the first electric drive motor 14 is reduced. The switchover occurs while the combustion engine 16 and / or the second electric drive motor 18 maintain traction in a third variant of the hybrid gear stage.

[0082] In hybrid mode, the first electric drive motor 14 can be decoupled when the combustion engine 16 and / or the second electric drive motor 18 are operated in a third variant of a hybrid gear stage. This allows for efficient combustion engine and / or hybrid driving operation using the combustion engine 16 and / or the second electric drive motor 18.

[0083] It is understood that the second electric drive motor 18 may be dimensioned smaller than the first electric drive motor 14, since the second electric drive motor 18 preferably does not have to perform any essential driving functions.

[0084] In Fig. Figure 4 shows another variant of a hybrid transmission 20 according to the invention. In contrast to the one in Fig. In the embodiment shown in Figure 2, the second electric drive motor 18 is not connected to the transmission via the fixed gear of the first spur gear pair ST1, but rather via a connecting gear, which is designed as a fixed gear and is arranged on the first transmission input shaft 24. This allows for a more variable gear ratio when connecting the second electric drive motor 18 to the hybrid transmission 20. In the embodiment shown, the second electric drive motor 18 is connected to the hybrid transmission 20 via a fixed gear on a rotor shaft of the second electric drive motor 18, which meshes with another fixed gear, the latter meshing with the connecting gear.

[0085] In Fig. Figure 5 shows another variant of a hybrid transmission 20 according to the invention. In contrast to the one in Fig. In the embodiment shown in Figure 4, the fixed and loose gears are reversed in the first spur gear pair ST1 and in the second spur gear pair ST2. It is understood that the fourth switching element D and the second switching element B are also reversed. Consequently, the countershaft 28 is designed without switching elements and has only fixed gears.

[0086] This embodiment is particularly suitable for variants in which the second electric drive motor 18 is connected to the hybrid transmission 20 by means of a connecting gear.

[0087] It goes without saying that exchanging a loose gear with a fixed gear is only conceivable for one of the spur gear pairs ST1, ST2.

[0088] In Fig. Figure 6 shows another variant of a hybrid transmission 20 according to the invention. In contrast to the one in Fig. In the embodiment shown in Figure 5, the arrangement of the loose and fixed gears is reversed in the third spur gear pair ST3. Consequently, the fixed gear of the third spur gear pair ST3 is located on the first transmission input shaft 24, and the loose gear is located on the countershaft 28. This also means that the third switching element C is located on the countershaft 28. In this embodiment, the first switching element A and the third switching element C can also be operated by a single actuator. However, this requires an additional shift fork.

[0089] In Fig. Figure 7 shows another variant of a hybrid transmission 20 according to the invention. In contrast to the one in Fig. The embodiment shown in 2 features the Fig. Figure 7 shows an alternative connection to the planetary gear set RS. The ring gear of the planetary gear set RS is effectively connected to the loose gear of the fourth spur gear pair ST4. The second transmission input shaft 26 is effectively connected to a planet carrier of the planetary gear set RS. Furthermore, the sun gear of the planetary gear set RS can be locked by inserting the sixth switching element F. The fifth switching element E is designed to effectively connect the second transmission input shaft, i.e., the planet carrier of the planetary gear set RS, to the sun gear of the planetary gear set RS. Consequently, in the illustrated embodiment, the planetary gear set RS can be locked by inserting the fifth switching element E.

[0090] In Fig. Figure 8 shows another variant of a hybrid transmission 20 according to the invention. In contrast to the one in Fig. In the embodiment shown in Figure 2, the connections on the planetary gear set RS are reversed. A ring gear of the planetary gear set RS is effectively connected to the loose gear of the fourth spur gear pair ST4 and can be effectively connected to the second transmission input shaft 26 by inserting the fifth switching element E. A planet carrier of the planetary gear set RS can be effectively connected to the second transmission input shaft 26 by inserting a sixth switching element F. The sun gear of the planetary gear set RS is fixed.

[0091] Furthermore, the double switching element comprising the fifth switching element E and the sixth switching element F is arranged at least sectionally radially and / or axially within the first electric drive machine 14.

[0092] The in the Fig. 7 and Fig. The 8 disclosed alternative connections of the RS planetary gear set are functionally equivalent to the connections according to the Fig. 2, Fig. 4, Fig. 5 and Fig. 6.

[0093] In Fig. Figure 9 shows another variant of a hybrid transmission 20 according to the invention. In contrast to the one in Fig. In the embodiment shown in Figure 2, the first transmission input shaft 24 comprises an internal combustion engine coupling K0. The internal combustion engine coupling K0 is designed to detachably connect the internal combustion engine 16 (not shown) to the first transmission input shaft 24 in a drive-effective manner. In the embodiment shown, the internal combustion engine coupling K0 is designed as a positive-locking switching element.

[0094] In Fig. Figure 10 shows another variant of a hybrid transmission 20 according to the invention. In contrast to the one in Fig. In the embodiment shown in Figure 9, the combustion engine coupling K0 is designed as a friction-fit switching element.

[0095] It is understood that the vehicle powertrain 12 or the hybrid transmission 20 can also be operated without an internal combustion engine clutch K0. Nevertheless, an internal combustion engine clutch K0 can be advantageous for various reasons, such as functional safety considerations. In particular, an internal combustion engine clutch K0 in the form of a friction-fit switching element, as in Fig. Figure 10 shows a towing start of the internal combustion engine 16. Furthermore, an internal combustion engine clutch K0 designed as a friction switching element can serve as an emergency starting element for the internal combustion engine 16.

[0096] 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 examples and not as limiting. The invention is not limited to the disclosed embodiments. Other embodiments or variations will become apparent to a person skilled in the art when using the present invention and upon a detailed analysis of the drawings, the disclosure, and the subsequent claims.

[0097] In the claims, the words "comprise" and "with" do not preclude the presence of further elements or steps. The undefined article "a" or "an" does not preclude the presence of multiple elements. A single element or unit can perform the functions of several of the units mentioned in the claims. The mere mention of some measures in several different dependent claims is not to be understood as precluding the advantageous use of a combination of these measures. Reference numerals in the claims are not to be understood restrictively. For example, a method for operating a motor vehicle powertrain 12 can be implemented in the form of a computer program executed on a control unit for the motor vehicle powertrain 12.A computer program can be stored / distributed on a non-volatile storage medium, such as an optical memory or a solid-state drive (SSD). A computer program can be distributed together with hardware and / or as part of hardware, for example, via the internet or via wired or wireless communication systems. Reference sign 10 motor vehicle 12 Automotive Powertrain 14 first electric drive motor 16 Internal combustion engine 18 second electric drive motor 20 hybrid transmissions 22 Energy storage 24 first gearbox input shaft 26 second gearbox input shaft 28 Countershaft 30 downforce 32 switching matrix A to F Switching elements K0 combustion engine clutch RS planetary gear set ST1 to ST4 spur gear pairs

Claims

[1] Hybrid transmission (20) 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 (20) to an internal combustion engine (16) and a second electric drive motor (18) of the motor vehicle (10); a second transmission input shaft (26) for operatively connecting the hybrid transmission (20) to a first electric drive motor (14) of the motor vehicle (10); a planetary gear set (RS) with a first planetary gear set element, a second planetary gear set element and a third planetary gear set element; a countershaft (28); spur gear pairs (ST1, ST2, ST3, ST4) arranged in several gear set levels to form gear steps; and several gearshift devices with shift elements (A, B, C, D, E, F) for engaging gear steps, wherein the first spur gear pair (ST1), the second spur gear pair (ST2) and the third spur gear pair (ST3) of the spur gear pairs (ST1, ST2, ST3, ST4) are assigned to form gear stages of the countershaft (28) and the first transmission input shaft (24); the fourth spur gear pair (ST4) of the spur gear pairs (ST1, ST2, ST3, ST4) is assigned to form gear stages of the first transmission input shaft (24), the second transmission input shaft (26) and the countershaft (28); and the first electric drive machine (14) can be decoupled in a variant of each hybrid gear stage (H1.3, H2.3, H3.3, H4.3) in order to enable efficient driving by means of the combustion engine (16) and / or the second electric drive machine (18). [2] Hybrid transmission (20) according to claim 1, wherein the planetary gear set (RS) has a first connection to the fourth spur gear pair (ST4); has a second connection to a housing and has a third connection to the first electric drive machine (14); and two of the aforementioned connections are designed as permanently fixed connections and one of these connections is designed as a switchable connection. [3] Hybrid transmission (20) according to one of the preceding claims, wherein the switching elements (A, B, C, D, E, F) are designed as positive-locking switching elements; and / or at least two of the switching elements (A, B, C, D, E, F) are designed as double switching elements and can be actuated by a double-acting actuator. [4] Hybrid transmission (20) according to one of the preceding claims, wherein the second transmission input shaft (26) is designed as a hollow shaft and surrounds the first transmission input shaft (24) at least in sections; and / or the first transmission input shaft (24) and the second transmission input shaft (26) are arranged axially parallel to the countershaft (28). [5] Hybrid transmission (20) according to one of the preceding claims, wherein the first transmission input shaft (24) comprises an internal combustion engine clutch (K0) for releasably drivingly connecting the first transmission input shaft (24) to the internal combustion engine (16). [6] Hybrid transmission (20) according to one of the preceding claims, wherein the hybrid transmission has exactly four spur gear pairs (ST1, ST2, ST3, ST4), exactly one planetary gear set (RS) and exactly six shift elements (A, B, C, D, E, F) to form four hybrid gear stages and two electric gear stages; in the case of three spur gear pairs (ST1, ST2, ST3) for forming the gear stages, the arrangement of the loose gear is interchangeable with the arrangement of the fixed gear; and / or an axial arrangement of three of the spur gear pairs (ST1, ST2, ST3) can be exchanged as required to form the gear stages. [7] Hybrid transmission (20) according to one of the preceding claims, wherein the hybrid transmission (20) is connectable to the internal combustion engine (16) at a first transmission input; and the hybrid transmission (20) is connectable to the first electric drive motor (14) at a second transmission input opposite the first transmission input; and / or the hybrid transmission (20) can be connected to the second electric drive motor (18) at the first transmission input by means of a spur gear pair of the spur gear pairs (ST1, ST2, ST3) for forming gear stages or a connecting gear. [8] Hybrid transmission (20) 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 countershaft (28) by means of the fourth spur gear pair (ST4); a second shift element (B) is designed to drive-effectively connect the first transmission input shaft (24) to the countershaft (28) by means of the second spur gear pair (ST2); a third shift element (C) is designed to drive-effectively connect the first transmission input shaft (24) to the countershaft (28) by means of the third spur gear pair (ST3); a fourth shift element (D) is designed to drive-effectively connect the first transmission input shaft (24) to the countershaft (28) by means of the first spur gear pair (ST1); a fifth shift element (E) is designed to drive-effectively connect the second transmission input shaft (26) to the fourth spur gear pair (ST4) without any gear ratio and further to drive-effectively connect it to the countershaft (28) by means of the fourth spur gear pair (ST4); and / or a sixth shift element (F) is designed to drive-connect the second transmission input shaft (26) through the planetary gear set (RS) to the countershaft (28) by means of the fourth spur gear pair (ST4). [9] Hybrid transmission (20) according to one of the preceding claims, wherein a first hybrid gear stage (H1) can be set by closing the first switching element (A), and preferably the fifth switching element (E) or sixth switching element (F); a second hybrid gear stage (H2) can be set up by closing the second switching element (B), and preferably the fifth switching element (E) or sixth switching element (F); a third hybrid gear stage (H3) can be set by closing the third switching element (C), and preferably the fifth switching element (E) or sixth switching element (F); a fourth hybrid gear stage (H4) can be set by closing the fourth switching element (D), and preferably the fifth switching element (E) or sixth switching element (F); a first electric gear stage (E1) can be set by closing the fifth switching element (E); and / or a second electric gear stage (E2) can be set up by closing the sixth switching element (F). [10] Motor vehicle drive train (12) for a motor vehicle (10), comprising: a hybrid transmission (20) according to one of the preceding claims; an internal combustion engine (16) connectable to the first transmission input shaft (24); a first electric drive motor (14) connected to the second transmission input shaft (26); and a second electric drive motor (18) which is drivingly connected to the first transmission input shaft (24). [11] Motor vehicle drive train (12) according to claim 10, wherein the second electric drive machine (18) can be controlled as a starter generator for starting the internal combustion engine (16); and / or can be operated as a generator by the combustion engine (16) in order to provide energy for serial creeping by means of the first electric drive machine (14). [12] Motor vehicle drive train (12) according to one of claims 10 or 11, wherein the first electric drive machine (14) is designed as a coaxial machine; and the planetary gear set (RS) and / or a double switching element is arranged at least in sections radially and / or axially within the first electric drive machine. [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 11 to 12; and an energy storage device (22) for storing energy to supply the electric drive machines (14, 18).

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