Compact hybrid transmission with simple mechanical design

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 to an electric drive motor (14) of the motor vehicle; a first partial transmission and a second partial transmission; a planetary gear set (RS), with three planetary gear set elements; a first countershaft (30); loose wheels and fixed wheels arranged in several wheelset levels to form gear steps; and a plurality of gearshift devices with shift elements (A, B, C, D, E, F, R, K3) for engaging the gear stages; wherein the planetary gear set is drive-connected to the second transmission input shaft; is drivingly connected to the second partial transmission by means of an intermediate shaft (28); and can be fixed or connected to the first transmission input shaft; wherein the first transmission input shaft (24) is designed to be free of an internal combustion engine clutch on the input side; and a reversing gear is arranged in a gear set plane in order to establish a mechanical reverse gear stage, wherein a sun gear of the planetary gear set (RS) can be fixed or connected to the first transmission input shaft (24); a planetary gear carrier of the planetary gear set is drivingly connected to the intermediate shaft (28); and a ring gear of the planetary gear set is drivingly connected to the second transmission input shaft (26).

Description

The present invention relates to a hybrid transmission, a motor vehicle drivetrain having such a hybrid transmission, a motor vehicle having such a motor vehicle drivetrain, and a method for operating such a motor vehicle drivetrain.Vehicles are increasingly being equipped with hybrid drives, i.e. with at least two different drive sources. Hybrid engines can contribute to reducing fuel consumption and pollutant emissions. Largely powertrains with an internal combustion engine and one or more electric motors have become established as a parallel hybrid or as a hybrid hybrid. Hybrid drives of this type have a substantially parallel arrangement of the internal combustion engine and of the electric drive in the power flow. In this case, it is possible to enable both superposition of the drive torques and actuation with purely internal combustion engine drive or purely electric motor drive. Since the drive torques of the electric drive and of the internal combustion engine can add up depending on the actuation, a comparatively smaller design of the internal combustion engine and / or its temporary shutdown is possible. This allows a significant reduction in CO2 emissionen to be achieved without significant losses in performance or comfort. The possibilities and advantages of an electric drive can thus be associated with the range, power and cost advantages of internal combustion engines.A disadvantage of the above-mentioned hybrid drives is a generally more complex design, since both drive sources transmit drive power to a drive shaft preferably with only one transmission. As a result, such transmissions are usually complicated and cost-intensive to produce. A reduction in the complexity in the design of a hybrid transmission is usually associated with a loss of variability.This drawback may be overcome, at least in part, by dedicated hybrid transmissions or dedicated hybrid transmissions (DHT), where an electric machine is integrated into the transmission to represent full scope of operation. For example, in the transmission, in particular the mechanical transmission part can be simplified, for example by omitting the reverse gear, wherein instead at least one electric machine is used.Dedicated hybrid transmissions can be derived from known transmission concepts, i.e. from dual clutch transmissions, converter planetary transmissions, continuously variable transmissions (CVT) or automated manual transmissions. The electric machine is in this case partly of the transmission.The laid-open specification DE 10 2013 215 114 A1 relates to a hybrid drive of a motor vehicle, which has an internal combustion engine with a drive shaft, an electric machine, which can be operated as a motor and as a generator and has a rotor, an automated transmission, which is designed in countershaft construction and has an input shaft and at least one output shaft, and a superposition transmission, which is designed in planetary construction and has two input elements and one output element. In this hybrid drive, it is provided that the superposition gear is arranged coaxially over a free end of the output shaft, and that the first input element of the superposition gear is connected in a rotationally fixed manner to a hollow shaft arranged coaxially over the output shaft, which for coupling the internal combustion engine via a coupling shift element is connectable in a rotationally fixed manner to a loose gear of the directly axially adjacent spur gear stage of the transmission and for bridging the superposition gear via a bridging shift element is connectable in a rotationally fixed manner to the second input element or the output element of the superposition gear, that the second input element of the superposition gear is permanently in a drive connection to the rotor of the electric machine, and that the output element of the superposition gear is connected in a rotationally fixed manner to the output shaft.The published patent application DE 10 2015 221 499 A1 relates to a drive arrangement for a hybrid vehicle having a hybrid drive with an internal combustion engine and an electric machine and a transmission with two transmission input shafts, wherein the drive arrangement comprises at least the following: a planetary transmission, wherein a first element of the planetary transmission can be connected to a first transmission input shaft in a rotationally fixed manner and wherein a second element of the planetary transmission can be connected to the electric machine in a rotationally fixed manner; a first shift element, via which a third element of the planetary transmission can be connected to the electric machine in a housing-fixed manner or in a rotationally fixed manner; a second shift element, via which the third element of the planetary transmission can be connected to the internal combustion engine in a rotationally fixed manner; a third shift element, via which the first transmission input shaft can be connected to the internal combustion engine in a rotationally fixed manner; a fourth shift element, via which the one second transmission input shaft can be connected to the internal combustion engine in a rotationally fixed manner; wherein the third shift element and the fourth shift element are formed by a first dual shift element, the actuator of which extends through a pot-like section of a drive shaft of the internal combustion engine, which surrounds the first dual shift element on the outside; and wherein the pot-like section extends as far as the second shift element.The laid-open specification DE 10 2018 217 827 A1 relates to a transmission of a motor vehicle. With a first drive shaft for a first drive unit. With a second drive shaft for a second drive unit. With an output shaft. A first subtransmission comprising the first drive shaft and a countershaft coupled to the first drive shaft via a constant transmission ratio, wherein gearwheels are arranged on the countershaft, which mesh exclusively in gearwheels arranged coaxially to the first drive shaft, wherein at least some of these gearwheels mesh in gearwheels arranged on the output shaft, and wherein both the first drive shaft and the countershaft are assigned shift elements which provide either a gear with a first number of gearwheel meshes or a winding path gear with a second number of gearwheel meshes. With a second subtransmission comprising the second drive shaft, which is designed as a planetary transmission, wherein a ring gear forms the second drive shaft, wherein a carrier is coupled to the output shaft via a gearwheel arranged coaxially to the first drive shaft, and wherein the planetary transmission is provided with switching elements, via which a sun gear can be connected fixedly to the housing or the planetary transmission can be brought into a block circulation. With a subtransmission coupling of the subtransmissions that can be provided via one of the shift elements assigned to the countershaft.The post-published laid-open specification DE 10 2020 203 802 A1 relates to a hybrid transmission for a motor vehicle drive train of a motor vehicle, having: a first transmission drive shaft for operatively connecting the hybrid transmission to an internal combustion engine of the motor vehicle; a planetary gear set comprising a sun gear, a planetary gear and a ring gear, wherein the planetary gear set is designed to be connected in a drive-effective manner to a first electric drive machine of the motor vehicle; a second transmission drive shaft, which is connected in a drive-effective manner to the planetary gear set; a first countershaft and a second countershaft; gearwheel pairs arranged in a plurality of gear set planes and consisting of loose gears and fixed gears for forming gear stages; a plurality of gear shift devices having shift elements for engaging the gear stages, wherein the shift elements comprise spur gear shift elements and planetary gear set shift elements; a connecting clutch having a shift element for drive-operatively connecting the first transmission drive shaft and the second transmission drive shaft; and an output; wherein the first transmission drive shaft and the second countershaft can be drive-operatively connected by means of a gearwheel pair of the gearwheel pairs consisting of loose gears and fixed gears to form gear stages; and the second transmission drive shaft and the first countershaft can be drive-operatively connected by means of a gearwheel pair of the gearwheel pairs consisting of loose gears and fixed gears to form gear stages.The laid-open specification DE 10 2012 218 367 A1 relates to a group transmission device having an electric machine, having a main transmission designed as a countershaft transmission, a front-mounted group upstream of the main transmission, and a rear-mounted group downstream of the main transmission. In the area of the main transmission, the front-mounted group and the rear-mounted group, a transmission ratio can be changed via transmission ratio stages that can be engaged in the force flow by means of positive-locking shifting elements and disengaged from the force flow. A torque of the electric machine can be introduced into the force flow at least during a transmission ratio change in the region of the front-mounted group. The front-mounted group comprises at least three gear stages that can be connected and disconnected, the main transmission comprises at least two gear stages that can be connected and disconnected, and the rear-mounted group comprises at least two gear stages that can be connected and disconnected.Against this background, a person skilled in the art is faced with the object of creating a compact hybrid transmission of mechanically simple design. In particular, a hybrid transmission having a sufficiently high number of gears for the internal combustion engine driving operation and at least two gears having a high transmission efficiency for the electric motor driving operation is to be provided.This object is achieved by a hybrid transmission for a motor vehicle drivetrain of a motor vehicle, having: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 transmissionhaving an electric drive machine of the motor vehicle;a first subtransmission and a second subtransmission;a planetary gear set having three planetary gear set members;a first countershaft;loose wheels and fixed wheels arranged in a plurality of wheel set planes for forming gear stages; anda plurality of gear shift devices having shift elements for engaging the gear stages; whereinthe planetary gear set is operatively connected in a drive-effective manner to the second transmission input shaft, is operatively connected in a drive-effective manner to the second subtransmission by means of an intermediate shaft, and can be fixed or connected to the first transmission input shaft, whereinthe first transmission input shaft is configured on the input side without an internal combustion engine clutch; andIn a gear set plane, a reversing gear is arranged to establish a mechanical reverse gear stage.The above object is furthermore achieved by a motor vehicle drive train for a motor vehicle, having:a hybrid transmission as defined above;an internal combustion engine connectable to the first transmission input shaft; andan electric drive machine which is operatively connected to the second transmission input shaft in a drive-effective manner.The above object is also achieved by a method for operating a motor vehicle drivetrain as defined above.The above object is finally achieved by a motor vehicle having a motor vehicle drive train as defined above and an energy store for storing energy for supplying the electric drive machine.Preferred embodiments of the invention are described in the dependent claims. It is understood that the features mentioned above and those still to be explained below can be used not only in the respectively specified combination, but also in other combinations or alone, 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.A compact and variable hybrid transmission can be provided by 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 an electric drive engine. An operative connection can be embodied both switchable and non-switchable. A first partial transmission and a second partial transmission can create a hybrid transmission of mechanically simple construction, with which a high combinability of the two drive machines can be achieved. An efficient EDA mode can be set up for starting by means of a planetary gear set, wherein preferably no friction clutch is required for starting. By being able to fix the planetary gear set, a further electric gear stage can be created. Furthermore, two modes of charging into neutral can be established with different rotational speed ratios of the two drive engines with respect to one another.The first transmission input shaft is designed to be free of internal combustion engine clutches on the input side. Additionally, a reversing gear is arranged in a gear set plane in order to establish a mechanical reverse gear stage. By means of a mechanical reverse gear stage, an EDA mode can also be used for reverse starting. A transmission input shaft configured free of internal combustion engine clutches makes it possible to create a technically simple and highly efficient hybrid transmission. In particular in combination with the planetary gear set, which permits electrodynamic starting, a comfortable and compact hybrid transmission with a simple mechanical design and simple actuation can be created.According to the invention, a sun gear of the planetary gear set can be fixed or connected to the first transmission input shaft. According to the invention, a planet carrier of the planetary gear set is also connected in a drive-effective manner to the intermediate shaft. Furthermore, according to the invention, a ring gear of the planetary gear set is operatively connected to the second transmission input shaft for driving purposes. By virtue of this advantageous connection of the planetary gear set, the electric drive machine can be operated at a low compensation rotational speed during electrodynamic starting or in electrodynamic shifting.In a further advantageous embodiment, the planetary gear set can be locked by engaging two shift elements. This makes it possible to establish a charge-in-neutral mode in which the internal combustion engine rotates in a fixed rotational speed ratio to the electric drive machine and is operatively connected thereto in a driving manner. In particular, it can be achieved that the electric drive machine rotates as fast as the internal combustion engine.In a further advantageous embodiment, a locking shift element of the shift elements is designed for locking the planetary gear set. As a result, a pretransmission can be effected by the planetary gear set, which can enable in particular a further electric gear stage and a further mode of charging into neutral.In a further advantageous embodiment, a first shifting element, preferably a second shifting element, a third shifting element and a fourth shifting element, are designed to drive-operatively shift one gear pair each. Additionally or alternatively, a fifth shift element is designed to connect the planetary gear set, in particular the sun gear of the planetary gear set, to the first transmission input shaft in a drive-effective manner. Furthermore additionally or alternatively, a connecting shift element is designed to connect the first transmission input shaft to the intermediate shaft in a drive-effective manner. Furthermore additionally or alternatively, a reverse gear shifting element is designed to drive-effectively shift a gearwheel triplet comprising a reverse gearwheel. This advantageous connection of the shift elements makes it possible to create a hybrid transmission with a high functional range, wherein only one single or two shift elements must be closed in each case for establishing the shift states. In particular, a highly efficient internal combustion engine operating mode can be set up, since only a single shift element is to be closed in each case for shifting at least two combustion gear stages.In a further advantageous embodiment, the hybrid transmission has a second countershaft. In addition, a gearwheel of the first subtransmission and preferably a gearwheel of the second subtransmission respectively mesh with a gearwheel on the first countershaft and a gearwheel on the second countershaft. Furthermore, in addition, the loose wheels and fixed wheels are arranged in exactly three wheelset planes to form gear stages. The hybrid transmission can be made axially compact by a second countershaft. In particular, two countershafts make so-called dual gear planes possible, in which a gearwheel on an input shaft is in engagement with a gearwheel on the first countershaft and a gearwheel on the second countershaft. This makes it possible to save components and weight for the hybrid transmission. By arranging the loose wheels and fixed wheels to form gear stages in exactly three gear set planes, an axially short hybrid transmission which nevertheless has a high range of functions can be created.In a further advantageous embodiment, an output comprises a differential gear which is in engagement with a gear-forming gearwheel. In particular, the differential gear is arranged in a gear set plane with the gear-forming gear wheel. This allows further weight for the hybrid transmission to be saved. Furthermore, an axial installation space requirement for the hybrid transmission can be reduced.In a further advantageous embodiment, the shifting elements are designed as form-locking shifting elements. Additionally or alternatively, at least two of the shift elements, in particular all shift elements, are designed as a double shift element and can be actuated by a double-acting actuator. This makes it possible to create an efficient and cost-effective hybrid transmission. A dual shift element makes it possible to construct the hybrid transmission with fewer components, since only one actuator has to be used to actuate a dual shift element. The control of the transmission is simplified. The transmission is of compact construction. It is understood that both the electric drive machine and the internal combustion engine can be used for synchronizing the shift elements.In a further advantageous embodiment, the electric drive machine is designed as a coaxial machine. In addition, the planetary gear set and / or at least one shift element are arranged at least in sections axially and / or radially within the electric drive machine. As a result, a highly efficient and in particular axially compact drive train can be created. The available installation space can be used advantageously.In a further advantageous embodiment, the electric drive machine can be connected to the output of the hybrid transmission independently of the internal combustion engine. As a result, the electric drive machine can advantageously maintain a tractive force when shifts for the internal combustion engine are carried out.In a further advantageous embodiment, the electric drive machine can be controlled as a starter generator for starting the internal combustion engine. Additionally or alternatively, the electric drive machine can be controlled as a charge generator for charging an energy store. As a result, the motor vehicle drive train can be operated efficiently. Fuel consumption may be reduced. Preferably, an additional starter for the internal combustion engine can be dispensed with.A locking of an element of a planetary gear set is to be understood in particular as a blocking of a rotation of the element about its axis of rotation.Preferably, the element is connected in a rotationally fixed manner to a static component such as a frame and / or a transmission housing by means of a shift element. It is also conceivable to brake the element until it stops.Blocking a planetary gear set comprises operatively connecting two gears and / or the planetary gear carrier and a gear of the planetary gear set such that they rotate together at the same rotational speed about the same point, preferably the center point of the planetary gear set. When blocking two gearwheels and / or a planet carrier and a gearwheel of the planetary gear set, the planetary gear set preferably acts like a shaft; in particular, no transmission ratio takes place in the planetary gear set.In this context, "drive-effectively connected" is to be understood to mean, in particular, a non-switchable connection between two components, which is provided for permanent transmission of a rotational speed, a torque and / or a drive power. The connection can be made either directly or via a fixed transmission ratio. The connection can be effected, for example, via a fixed shaft, a toothing, in particular a spur gear toothing, and / or a winding means, in particular a traction mechanism transmission.In this context, "drive-operatively connectable", "can be drive-operatively connected" or "is designed for drive-operatively connecting" is to be understood to mean, in particular, a switchable connection between two components, which, in a closed state, is provided for temporarily transmitting a rotational speed, a torque and / or a drive power. In an open state, the switchable connection preferably temporarily transmits substantially no rotational speed, no torque and / or no drive power.Static charging or charging-in-neutral is to be understood in particular as the operation of the electric drive machine as a generator, preferably when at a standstill with the internal combustion engine running, in order to fill an energy store and / or to feed on-board electronics.An actuator is in particular a component that converts an electrical signal into a mechanical movement. Preferably, actuators used with dual shift elements execute movements in two opposite directions to shift one shift element of the dual shift element in the first direction and to shift the other shift element in the second direction.A gear stage change is effected in particular by deactivation of a shift element and / or a clutch and simultaneous activation of the shift element and / or the clutch for the next higher or lower gear stage. The second shifting element and / or the second clutch thus takes over the torque piece by piece from the first shifting element and / or from the first clutch until the entire torque is taken over by the second shifting element and / or the second clutch at the end of the gear stage change. In the case of previous synchronization, a gear change can take place more quickly; preferably, form-locking shift elements can be used in this case.An internal combustion engine may in particular be any engine which can produce a rotary movement by burning a drive means such as petrol, diesel, kerosine, ethanol, liquid gas, car gas etc. An internal combustion engine may be, for example, a spark ignition engine, a diesel engine, a Wahl engine or a two-stroke engine.In the case of series driving or creep, an electric drive machine of a motor vehicle is operated in a generator mode by an internal combustion engine of the motor vehicle. The energy thus generated is then made available to a further electric drive machine of the motor vehicle in order to provide drive power.An electric vehicle axle, or electric axle for short, is preferably a non-main drive axle of a motor vehicle, in which drive power can be transmitted to wheels of the motor vehicle by means of an electric drive machine. It is understood that the electric drive machine can also be connected by means of a transmission. A tractive force can be fully or partially maintained by means of an electric axle when a gear change takes place in the transmission for a main drive axle. Furthermore, an all-wheel functionality can be set up at least partially by means of an electrical axle.An electrodynamic starting element (EDA) has the effect that a rotational speed superposition of internal combustion engine rotational speed and electric drive engine rotational speed takes place via one or more planetary gear sets, so that a motor vehicle can be started from standstill while the internal combustion engine is running, preferably without a friction clutch. The electric drive machine supports a torque. Preferably, the internal combustion engine is no longer separable from the transmission by a starting clutch or the like. By using an EDA, it is preferably possible to dispense with the starter, generator and starting clutch or hydrodynamic converter. In this case, an EDA is in particular so compact that all components are located in the series-produced clutch housing without lengthening the transmission. The electrodynamic starting element can be firmly connected, for example, via a soft-tuned torsion damper to an internal combustion engine and, in particular, to a flywheel of an internal combustion engine. Thus, the electric prime mover and the internal combustion engine may be selectively operated simultaneously or alternatively. If the motor vehicle stops, the electric drive engine and the internal combustion engine can be switched off. Due to a good controllability of the electric drive machine, a very high starting quality is achieved, which can correspond to that of a drive with converter clutch.In a so-called electrodynamic shift (EDS), as in EDA starting, a rotational speed superposition of internal combustion engine rotational speed and electric drive engine rotational speed takes place via one or more planetary gear sets. At the start of the shift, the torques of the electric drive machine and of the internal combustion engine are adapted, so that the shift element to be disengaged becomes load-free. After this shift element has been opened, a speed adaptation takes place while maintaining the tensile force, so that the shift element to be engaged becomes synchronous. After the closing of the shift element, the load distribution between the internal combustion engine and the electric drive machine takes place as desired depending on the hybrid operating strategy. The electrodynamic shifting method has the advantage that the shifting element to be shifted of the target gear is synchronized by the interaction of the electric drive machine and the internal combustion engine, wherein the electric drive machine is preferably precisely controllable. Another advantage of the EDS shift method is that a high tractive force can be achieved since the torques of the internal combustion engine and the electric machine are summed in the hybrid transmission.The invention will be described and explained in more detail below with reference to some selected exemplary embodiments in conjunction with the accompanying drawings. The following are shown: FIG. 1 shows a schematic top view of a motor vehicle having a motor vehicle drivetrain according to the invention; FIG. 2 shows a schematic simplified illustration of a hybrid transmission according to the invention; FIG. 3 schematically shows the shift states of the hybrid transmission according to FIG. 2 ; FIG. 4 shows a variant of a hybrid transmission according to the invention; FIG. 5 shows a further variant of a hybrid transmission according to the invention; FIG. 6 shows a further variant of a hybrid transmission according to the invention; FIG. 7 shows a further variant of a hybrid transmission according to the invention; FIG. 8 shows a further variant of a hybrid transmission according to the invention; FIG. 9 shows a schematic simplified illustration of a hybrid transmission according to the invention; FIG. 10 schematically shows the shift states of the hybrid transmission according to FIG. 9 ; FIG. 11 shows a further variant of a hybrid transmission according to the invention; and FIG. 12 shows a further variant of a hybrid transmission according to the invention.FIG. 1 schematically shows a motor vehicle 10 having a motor vehicle drivetrain 12. The motor vehicle powertrain 12 includes an electric prime mover 14, an internal combustion engine 16, and a hybrid transmission 18. The hybrid transmission 18 is connected to a front axle of the motor vehicle 10. It is understood that the hybrid transmission 18 can also be connected to the rear axle of the motor vehicle 10. By means of the motor vehicle drive train 12, drive power of the electric drive machine 14 and / or of the internal combustion engine 16 is supplied to the wheels of the motor vehicle 10. The motor vehicle 10 further has an energy store 22 for storing energy which serves to supply the electric drive machine 14.FIG. 2 schematically shows a simplified illustration of a hybrid transmission 18 according to the invention in a motor vehicle drivetrain 12. The illustration corresponds to a type of circuit diagram. The configurable translations are represented in squares and are denoted by an "i" with an index. These transmission ratios are preferably set up by gear wheel pairs. Furthermore, eight switching elements A-F, K3, R are shown in the manner of a switch.The hybrid transmission 18 has a first transmission input shaft 24 and a second transmission input shaft 26. The first transmission input shaft 24 is operatively connected to the internal combustion engine 16 in a drive-effective manner. The second transmission input shaft 26 is connected in a drive-effective manner to the electric drive machine 14 and can introduce drive power into a schematically illustrated planetary gear set RS.The planetary gear set RS is shown as a circle in the illustration, wherein the three planetary gear set elements, i.e. the ring gear Ho, the sun gear So and the planetary gear carrier or carrier S are marked with letters at the corresponding point of the circle. A transmission ratio i 0 can be established by means of the planetary gear set RS. The second transmission input shaft 26 is connected to the ring gear Ho of the planetary gear set RS. The planet carrier or carrier S of the planetary gear set RS is connected to an intermediate shaft 28. The sun gear So of the planetary gear set RS is fixable or connectable to the first transmission input shaft 24.The hybrid transmission 18 further comprises a first countershaft 30, which is connected via an output transmission ratio i ab to an output 32 and in particular to a differential of the output 32.By engaging a first shift element A, the intermediate shaft 28 can be connected to the first countershaft 30 in a drive-effective manner via a transmission ratio i V1 / E1.By engaging a second shift element B, the first transmission input shaft 24 can be connected in a drive-effective manner via a transmission ratio i V2 in a drive-effective manner to the first countershaft 30. A third shift element C establishes a drive-effective connection of the first transmission input shaft 24 via a transmission ratio i V3 with the first countershaft 30.By engaging a fourth shift element D, the intermediate shaft 28 can be connected to the first countershaft 30 in a drive-effective manner via a transmission ratio I E2.By engaging a locking shift element E, the sun gear So of the planetary gear set RS can be connected in a drive-effective manner to a torque-proof component, for example a transmission housing, and the planetary gear set RS can thus be locked.A sixth shift element F is designed to connect the planetary gear set RS, in particular the sun gear So of the planetary gear set RS, to the first transmission input shaft 24 in a drive-effective manner.By engaging a connecting shift element K 3, the first transmission input shaft 24 can be connected in a drive-effective manner to a planet carrier or carrier S of the planetary gear set RS.By engaging a reverse gear shifting element R, the intermediate shaft 28 can be connected in a drive-effective manner via a reverse gear ratio I R to the first countershaft 30.A base gearset of the hybrid transmission 18 consequently consists of two partial transmissions, the first partial transmission being connected to the internal combustion engine 16 and comprising at least two gear stages. The gear stages can be established via the second shifting element B and the third shifting element C.The second partial transmission is operatively connected to the electric drive machine 14 via the planetary gear set RS and has two forward gear stages and one reverse gear stage. These can be established via the first shift element A, the fourth shift element D or the reverse gear shift element R. In addition, a connection between the two partial transmissions can be established via the connection switching element K 3. For example, a first gear stage of the second subtransmission can also be used by the internal combustion engine 16. Furthermore, charging to neutral is possible by the connection switching element K 3.The planetary gear set RS can serve as a pretransmission in the second subtransmission when the locking shift element E is engaged. If the sixth shift element F is engaged, an electrodynamic superposition state or an EDX mode can be implemented on the planetary gear set RS, wherein both forward and reverse electrodynamic approach can be made. As a result, starting is possible even in the case of an empty energy store 22.All the shift elements A to F, R, K 3 can be designed as form-locking shift elements, for example claw shift elements. It is understood that a connection of the electric drive machine 14 can be made both coaxially and axially parallel.Furthermore, the following combinations of switching elements to form a dual switching element are possible. The first switching element A can be combined with the fourth switching element D to form a dual switching element. The second switching element B can be combined with a third switching element C to form a dual switching element. The fixing switching element E can be combined with a sixth switching element F to form a dual switching element. In addition, the reverse gear shift element R can be combined with the connecting shift element K 3 to form a dual shift element.If the fifth switching element F is closed, a so-called EDA mode is set up. In this, the planetary gear set RS serves as a superposition transmission, wherein the electric drive machine 14 is connected to the ring gear Ho of the planetary gear set RS and the internal combustion engine 16 is connected to the sun gear So of the planetary gear set RS by means of the sixth shift element F. The planet carrier or carrier S of the planetary gear set RS is connected to the output 32 via one of the transmission stages i V1 / E1, i E2 or i R wherein an EDA-V1, an EDA-V2 or an EDA-R mode is correspondingly established. This makes it possible to approach and travel, in particular, even when the energy store 22 is empty.FIG. 3 schematically shows the shift states of the hybrid transmission 18 according to FIG. 2 in a shift matrix 34.The first column of the shift matrix shows the combustion gear stages V 1 to V 3, three electrodynamic superposition states EDA-V 1, EDA-V 2, EDA-R, two electric gear stages E 1, E 2 and two states for charging in neutral LiN 1, LiN 2. The second to ninth columns show the shift states of the shift elements A to F, of the reverse gear shift element R and of the connection shift element K 3, wherein an "X" means that the respective shift element is closed, that is to say connects the assigned transmission components to one another in a drive-effective manner. If no entry is present, it is to be assumed that the corresponding switching element is open, i.e. does not transmit any drive power.To establish a first combustion gear stage V 1, the first shifting element A and the connecting shifting element K 3 are to be closed.A second combustion gear stage V 2 is established by engaging the second shift element B.Closing the third shift element C establishes a third combustion gear stage V 3.A first electrodynamic superposition state EDA-V 1 can be established by closing the first switching element A and the sixth switching element F.A second electrodynamic superposition state EDA-V 2 can be established by closing the fourth switching element D and the sixth switching element F.Closing the sixth shift element F and the reverse gear shift element R establishes a third, reverse-directed electrodynamic superposition state EDA-R.A first electric gear stage E 1 can be established by closing the first switching element A and the locking switching element E.Closing the fourth shift element D and the locking shift element E establishes a second electric gear stage E 2.A first state of charging to neutral LiN 1 may be established by closing the fixing switching element E and the connection switching element K 3.Closing the sixth shift element F and the connection shift element K 3 establishes a second state of charging to neutral LiN 2.Electric driving is possible in the electric gear stages E 1 or E 2. In these states, the internal combustion engine 16 is decoupled, that is to say the second shift element B, the third shift element C, the sixth shift element F and the connecting shift element K 3 are open. The first electric speed stage E 1 serves as a main electric speed stage. From this, a direct transition into the first combustion gear stage V 1, the second combustion gear stage V 2 or the third combustion gear stage V 3 is possible by closing the connection shifting element K 3 for the first combustion gear stage V 1, the second shifting element B for the second combustion gear stage V 2 or the third shifting element C for the third combustion gear stage V 3.A direct transition into the second combustion gear stage V 2 or the third combustion gear stage V 3 is possible from the second electric gear stage E 2, wherein the second shifting element B is closed for a transition into the second combustion gear stage V 2 or the third shifting element C is closed for a transition into the third combustion gear stage V 3. By means of these shift options, a shift between the first combustion gear stage V 1, the second combustion gear stage V 2 and the third combustion gear stage V 3 can be carried out with traction force assistance by the electric drive machine 14. In these states, the electric drive machine 14 is connected to the output 32 in the first electric gear stage E 1 or the second electric gear stage E 2 independently of the internal combustion engine 16. A shift from the first combustion gear V 1 to the second combustion gear V 2 may be supported via the first electric gear E 1.For driving in the internal combustion engine, the internal combustion engine gear stages V 1 to V 3 are available.Synchronization of the shift elements can be effected by regulating the rotational speed of the electric drive machine 14. Alternatively, a speed control of the internal combustion engine 16 can also take place.It is understood that in internal combustion engine operation, the electric drive machine 14 can also be decoupled in order to reduce drag losses.FIG. 4 shows a detailed schematic illustration of the hybrid transmission 18 according to FIG. 2.The electric drive machine 14 is designed as an axially parallel drive machine and is connected in a drive-effective manner to the second transmission input shaft 26 by means of a traction drive, a toothed wheel chain or a chain drive. The internal combustion engine 16, not shown, is connected to the hybrid transmission 18 by means of the first transmission input shaft 24, which is preferably designed free of internal combustion engine clutches.As seen from the connection side of the internal combustion engine 16, not shown, the individual transmission components are arranged in the hybrid transmission 18 as follows. First, a gearwheel pair for establishing the transmission ratio iV3, then a dual shifting element comprising the third shifting element C and the second shifting element B, and in the same gear set plane an output gearwheel for establishing the output transmission ratio i Ab, which gearwheel meshes with a differential of the output 32. The gearwheel pair for establishing the transmission ratio i V2, a gearwheel pair for establishing the reverse transmission ratio i R and a dual shift element comprising the reverse shift element R and the connecting shift element K3 are then arranged in the hybrid transmission 18. Adjacent to this, a gearwheel pair for establishing the transmission ratio i E2, then the dual shifting element comprising the fourth shifting element D and the first shifting element A and a gearwheel for establishing the transmission ratio i V1 / E1 are arranged in the hybrid transmission 18. Adjacent to this, the planetary gear set RS, then a connecting gearwheel for connecting the electric drive machine 14 and the dual shift element comprising the locking shift element E and the sixth shift element F, are arranged in the hybrid transmission 18.The intermediate shaft 28 is designed as a hollow shaft and surrounds the first transmission input shaft 24 at least in sections. The first countershaft 30 is designed as a solid shaft and is arranged axially parallel to the first transmission input shaft 24 and second transmission input shaft 26.The first transmission input shaft 24 is arranged on a transmission axis A 1. The first countershaft 30 is arranged on a transmission axis A 2 and an output 32 and in particular a differential of the output 32 is arranged on a transmission axis A 3. The dual shift element comprising the fourth shift element D and the first shift element A are arranged on the first countershaft 30. The remaining dual shift elements are arranged on the first transmission input shaft 24. Accordingly, the idler and fixed wheels of the gearwheel pairs are also arranged on the shafts 24, 30, 28, wherein the idler wheels of the gearwheel pairs are always arranged on the same shaft as the corresponding shifting element.FIG. 5 shows a further variant of a hybrid transmission 18 according to the invention. In contrast to the embodiment shown in FIG. 4, the dual shifting element comprising the fourth shifting element D and the first shifting element A is arranged between the gear set plane comprising the gearwheel pair for establishing the transmission ratio iE2and the gear set plane comprising the gearwheel triplet for establishing the reverse transmission ratio iR. As a result, the hybrid transmission 18 can be of axially shorter construction, since the dual shift element comprising the reverse gear shift element R and the connecting shift element K 3 and the dual shift element comprising the first shift element A and the fourth shift element D are arranged in an axial plane. The dual switching element comprising the first switching element A and the fourth switching element D comprises for this purpose an non-conventional switching element with an over concept.The first countershaft 30 is divided into two, wherein a part to the left of the dual shifting element comprising the first shifting element A and the fourth shifting element D comprises exclusively fixed gears and a part to the right of the dual shifting element comprising the first shifting element A and the fourth shifting element D comprises a loose gear and a fixed gear. The idler gear can be operatively connected to the part to the left of the first countershaft 30 in a drive-effective manner by closing the fourth shift element D, and the fixed gear can be operatively connected to the left part of the first countershaft 30 in a drive-effective manner by closing the first shift element A.FIG. 6 shows a further variant of a hybrid transmission 18 according to the invention. In contrast to the embodiment shown in FIG. 4, the dual shift element comprising the third shift element C and the second shift element B is arranged on the first countershaft 30. Furthermore, the dual shift element including the fourth shift element D and the first shift element A is arranged on the intermediate shaft 28. It is understood that the gear wheel pairs assigned to the two aforementioned dual shifting elements are likewise interchanged with respect to the arrangement of the fixed wheels and loose wheels, so that, as already described above, the loose wheels of the corresponding gear wheel pairs are arranged on the shaft to which the dual shifting element is also assigned.FIG. 7 shows a further variant of a hybrid transmission 18 according to the invention. In contrast to the embodiment shown in FIG. 4, the output drive 32 is in engagement with a gear-forming gearwheel, in particular a gear-forming fixed gear of the transmission stage i V3. This makes it possible to save on an output gearwheel. However, the transmission ratio i Ab of the output drive 32 can no longer be selected independently.FIG. 8 shows a further variant of a hybrid transmission 18 according to the invention. In contrast to the embodiments shown hitherto, the hybrid transmission 18 according to FIG. 8 comprises a second countershaft 36.Furthermore, the electric drive machine 14 is designed as a coaxial machine and surrounds the planetary gear set RS and the dual shift element comprising the locking shift element E and the sixth shift element F radially and / or axially at least in sections.The gearwheels for establishing the transmission ratio stages i V2 and i V3 or i V1 / E1 and i E2 can be arranged on different countershafts 30, 36 and use a common fixed gearwheel, i.e. form a so-called dual gearwheel plane. The gearwheels which form the shorter gear stages are preferably arranged on the first countershaft 30, which in the embodiment shown has a short final transmission ratio i Ab1. The gears for forming the longer ratio gears are arranged on the second countershaft 36, which in the example shown has a longer final ratio i Ab2.Consequently, the dual shift element comprising the fourth shift element D and the first shift element A is disengaged and comprises two individual shift elements, wherein the first shift element A is arranged on the first countershaft 30 and the fourth shift element D is arranged on the second countershaft 36.In addition, the dual shift element comprising the third shift element C and the second shift element B is disengaged, wherein the second shift element B is arranged on the first countershaft 30 and the third shift element C is arranged on the second countershaft 36.The gear pairs or gears for forming the gear stages are consequently arranged in three gear set planes. The gearwheel triplet for establishing a reverse gear ratio i R is assigned to the first transmission input shaft 24 and to the first countershaft 30.FIG. 9 shows, analogously to FIG. 2, a simplified illustration of a hybrid transmission according to the invention in the manner of a shift diagram. In contrast to the embodiment shown in FIG. 2, the hybrid transmission 18 according to FIG. 9 does not comprise a second shift element B. The other connections are identical. It is understood that, by omitting the second shift element B, the transmission stage i V2 is also omitted.FIG. 10 shows the shift states of the hybrid transmission according to FIG. 9 in a shift matrix 38 analogous to the shift matrix 34 of FIG. 3. For the sake of clarity, all shift states have been recorded, wherein the shift states differ only in the shift state for the second combustion gear stage V 2. This is established by engaging the fourth switching element D and the connection switching element K 3. Consequently, the ratio i E3 is also used for establishing a combustion gear stage and is consequently denoted by i V2 / E2 in FIGS. 10, 11 and 12.FIG. 11 shows a detailed schematic illustration of the hybrid transmission 18 according to FIG. 9. In contrast to the embodiment shown in FIG. 4, as already described above, the hybrid transmission 18 is formed without the second shifting element B and the associated gearwheel pair which establishes the transmission ratio i V2. The other connections and arrangements of the transmission components are analogous to the embodiment shown in FIG. 4.FIG. 12 shows a detailed schematic illustration of the hybrid transmission 18 according to FIG. 9. In contrast to the embodiment shown in FIG. 8, the hybrid transmission 18 according to FIG. 12 does not comprise a second shifting element B and no associated idler gear on the first countershaft 30. The other arrangements and configurations of the transmission components are identical to the embodiment shown in FIG. 8.By saving the second shift element B and the associated gearwheel or gearwheel pair, it is possible to further reduce the installation space requirement for the hybrid transmission 18 and the installation outlay. However, this reduction results in a limited startability. For example, starting of the internal combustion engine 16 from the first electric gear stage E 1 is no longer possible in the second combustion gear stage V 2.The invention has been fully described and explained with reference to the drawings and the specification. The description and explanation are to be taken by way of example and not limitation. 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, as well as upon a detailed analysis of the drawings, disclosure and appended claims.In the claims, the words "comprise" and "with" 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 unit may perform the functions of several of the units recited in the claims. The mere naming of some measures in several different dependent claims is not to be understood as meaning that a combination of these measures cannot likewise be used advantageously. Reference signs in the patent claims should be understood to be non-limiting. A method for operating a motor vehicle drivetrain 12 can be realized, for example, in the form of a computer program which is executed on a control device for the motor vehicle drivetrain 12. A computer program can be stored / distributed on a non-volatile data carrier, for example on an optical memory or on a solid state drive (SSD). A computer program can be distributed together with hardware and / or as part of hardware, for example by means of the Internet or by means of wired or wireless communication systems.REFERENCE NUMERALS:10 Motor vehicle 12 motor vehicle drive train 14 electric drive machine 16 internal combustion engine 18 hybrid transmission 22 energy store 24 first transmission input shaft 26 second transmission input shaft 28 intermediate shaft 30 first countershaft 32 output 34 shift matrix 36 second countershaft 38 shift matrix A 1-A 4 transmission axles A-D shift elements E locking shift element F fifth shift element K 3 connecting shift element R reverse gear shift element W transmission shafts I establishable transmission ratios

Claims

Hybrid transmission (18) for a motor vehicle drive train (12) of a motor vehicle (10), having: 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 to an electric drive engine (14) of the motor vehicle; a first subtransmission and second subtransmission; a planetary gear set (RS) having three planetary gear set elements; a first countershaft (30); idler gears and fixed gears arranged in a plurality of gear set planes for forming gear stages; and a plurality of gear shifting devices having shifting elements (A, B, C, D, E, F, R, K3) for engaging the gear stages; wherein the planetary gear set is operatively connected in a drive-effective manner to the second transmission input shaft; is operatively connected in a drive-effective manner to the second subtransmission by means of an intermediate shaft (28); and being fixable or connectable to the first transmission input shaft; wherein the first transmission input shaft (24) is formed on the input side without engine clutch; and a reversing gear is arranged in a gear set plane in order to establish a mechanical reverse gear stage, wherein a sun gear of the planetary gear set (RS) is fixable or connectable to the first transmission input shaft (24); a planetary gear carrier of the planetary gear set is connected in a drive-effective manner to the intermediate shaft (28); and a ring gear of the planetary gear set is connected in a drive-effective manner to the second transmission input shaft (26).Hybrid transmission (18) according to Claim 1, wherein the planetary gear set can be locked by engaging two shift elements (F, K3).Hybrid transmission (18) according to Claim 1 or 2, wherein a locking shift element (E) of the shift elements is designed to lock the planetary gearset (RS).Hybrid transmission (18) according to one of the preceding claims, wherein a first shift element (A), preferably a second shift element (B), a third shift element (C) and a fourth shift element (D), are designed to drive-operatively shift in each case one gearwheel pair; a fifth shift element (F) is designed to drive-operatively connect the planetary gear set (RS), in particular the sun gear of the planetary gear set, to the first transmission input shaft (24); a connection shift element (K3) is designed to drive-operatively connect the first transmission input shaft to the intermediate shaft (28); and / or a reverse gear shift element (R) is designed to drive-operatively shift a gearwheel triplet comprising a reverse gearwheel.Hybrid transmission (18) according to one of the preceding claims, wherein the hybrid transmission has a second countershaft (36); a gearwheel of the first subtransmission and preferably a gearwheel of the second subtransmission respectively meshes with a gearwheel on the first countershaft (30) and a gearwheel on the second countershaft; and the loose wheels and fixed wheels are arranged in exactly three gear set planes to form gear stages.The hybrid transmission (18) of any preceding claim, wherein an output (32) comprises a differential gear engaged with a gear forming gear.Hybrid transmission (18) according to one of the preceding claims, wherein the shift elements (A, B, C, D, E, F, R, K3) are designed as form-locking shift elements; and / or at least two of the shift elements, in particular all shift elements, are designed as dual shift elements and can be actuated by a double-acting actuator.A motor vehicle drive train (12) for a motor vehicle (10), comprising: a hybrid transmission (18) according to any one of the preceding claims; an internal combustion engine (16) connectable to the first transmission input shaft (24); and an electric drive engine (14) drivingly connected to the second transmission input shaft (26).Motor vehicle drive train (12) according to Claim 8, wherein the electric drive machine (14) is designed as a coaxial machine; and the planetary gear set (RS) and / or at least one shift element (E, F) are arranged at least in sections axially and / or radially within the electric drive machine.Motor vehicle drive train (12) according to either of Claims 8 and 9, wherein the electric drive machine (14) can be connected to the output (32) of the hybrid transmission (18) independently of the internal combustion engine (16).Motor vehicle drive train (12) according to one of Claims 8 to 10, wherein the electric drive machine (14) can be actuated as a starter generator for starting the internal combustion engine (16); and / or can be actuated as a charging generator for charging an energy store (22).Method for operating a motor vehicle drivetrain (12) according to one of Claims 8 to 11.A motor vehicle (10) comprising: a motor vehicle drive train (12) according to any of claims 8 to 11; and an energy store (22) for storing energy for supplying power to the electric drive machine (14).

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