DE102021205344A1 - Gear-free, power-shiftable hybrid transmission - Google Patents

Abstract

The present invention relates to a hybrid transmission (18) for a motor vehicle drive train (12) of a motor vehicle (10), having: a first transmission input shaft (26) for operatively connecting the hybrid transmission to an internal combustion engine (16) of the motor vehicle; a second transmission input shaft (28) for operatively connecting the hybrid transmission to a first electric drive machine (14) of the motor vehicle; a first intermediate shaft (30); a second intermediate shaft (32) drivingly connected to the first transmission input shaft; a countershaft (36); Spur gear pairs (ST1, ST2, ST3, ST4) arranged in several wheel set planes to form gear steps; a plurality of gear shifting devices with shifting elements (A, B, C, D) for engaging the gear stages; a planetary gear set (RS), which is connected to the second transmission input shaft, the first intermediate shaft and via a pair of spur gears to the countershaft; and an output (40), the gears, pairs of spur gears and associated shifting elements assigned to the second intermediate shaft being interchangeable in their axial sequence; and the pairs of spur gears and toothed wheels non-rotatably connected to the planetary gear set and the planetary gear set and the associated shifting elements are interchangeable in their axial sequence.

Description

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

Vehicles are increasingly being equipped with hybrid drives, ie with at least two different drive sources. Hybrid drives can help reduce fuel consumption and pollutant emissions. Drive trains with an internal combustion engine and one or more electric motors as parallel hybrids or as mixed hybrids have largely become established. Such hybrid drives have a substantially parallel arrangement of the internal combustion engine and the electric drive in the power flow. Here, both a superimposition of the drive torques and a control with a purely internal combustion engine drive or a purely electric motor drive can be made possible. Since the drive torques of the electric drive and the internal combustion engine can add up depending on the activation, a comparatively smaller design of the internal combustion engine and/or its temporary shutdown is possible. In this way, a significant reduction in CO ₂ emissions can be achieved without significant losses in 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.

A disadvantage of the hybrid drives mentioned above is their generally more complex structure, since both drive sources preferably transmit drive power to a drive shaft with only one transmission. As a result, such transmissions are usually complicated and expensive to produce. A reduction in complexity in the design of a hybrid transmission usually goes hand in hand with a loss of variability.

This disadvantage can be at least partially overcome by means of dedicated hybrid transmissions or "Dedicated Hybrid Transmissions" (DHT), in which an electric machine is integrated into the transmission to provide the full range of functions. For example, the mechanical transmission part in particular can be simplified in the transmission, for example by eliminating the reverse gear, with at least one electric machine being used instead.

Dedicated hybrid transmissions can emerge from known transmission concepts, i.e. from double clutch transmissions, converter planetary transmissions, continuously variable transmissions (CVT) or automated manual transmissions. The electric machine becomes part of the transmission.

The disclosure document 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 that can be operated as a motor and as a generator with a rotor, an automated manual transmission designed in countershaft design with an input shaft and at least one output shaft, and a superimposed transmission designed in planetary design with two input elements and one output element having. 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 non-rotatably connected to a hollow shaft arranged coaxially above the output shaft, which is non-rotatably connected to a loose wheel for coupling the internal combustion engine via a coupling shifting element the directly axially adjacent spur gear stage of the manual transmission and for bridging the superimposed gear via a bridging shifting element can be connected in a torque-proof manner to the second input element or the output element of the superimposed gear, that the second input element of the superimposed gear is permanently in drive connection with the rotor of the electric machine, and that the output element of the superimposed gear is rotatably connected to the output shaft.

Against this background, a person skilled in the art is faced with the task of creating a compact hybrid transmission. In particular, a hybrid transmission is to be created with which electrodynamic starting and electrodynamic shifting are possible.

• einer ersten Getriebeeingangswelle zum Wirkverbinden des Hybridgetriebes mit einer Verbrennungsmaschine des Kraftfahrzeugs;
• einer zweiten Getriebeeingangswelle zum Wirkverbinden des Hybridgetriebes mit einer ersten elektrischen Antriebsmaschine des Kraftfahrzeugs;
• einer ersten Zwischenwelle;
• einer zweiten Zwischenwelle, die antriebswirksam mit der ersten Getriebeeingangswelle verbunden ist;
• einer Vorgelegewelle;
• in mehreren Radsatzebenen angeordneten Stirnradpaaren zum Bilden von Gangstufen;
• mehreren Gangschaltvorrichtungen mit Schaltelementen zum Einlegen der Gangstufen;
• einem Planetenradsatz, der mit der zweiten Getriebeeingangswelle, einer ersten Zwischenwelle und über ein Stirnradpaar mit der Vorgelegewelle verbunden ist; und einem Abtrieb, wobei
• die der zweiten Zwischenwelle zugeordneten Zahnräder, Stirnradpaare sowie die zugehörigen Schaltelemente in ihrer axialen Reihenfolge vertauschbar sind; und
• die mit dem Planetenradsatz drehfest verbundenen Stirnradpaare und Zahnräder sowie der Planetenradsatz und die zugehörigen Schaltelemente in ihrer axialen Reihenfolge vertauschbar sind.

This problem is solved by a hybrid transmission for a motor vehicle drive train of a motor vehicle, with:

• a first transmission input shaft for operatively connecting the hybrid transmission to an internal combustion engine of the motor vehicle;
• a second transmission input shaft for operatively connecting the hybrid transmission to a first electric drive machine of the motor vehicle;
• a first intermediate shaft;
• a second intermediate shaft drivingly connected to the first transmission input shaft;
• a countershaft;
• Spur gear pairs arranged in several wheelset planes to form gear steps;
• a plurality of gear shifting devices with shifting elements for engaging the gear ratios;
• a planetary gear set which is connected to the second transmission input shaft, a first intermediate shaft and via a pair of spur gears to the countershaft; and an output where
• the gears, pairs of spur gears and the associated switching elements assigned to the second intermediate shaft can be interchanged in their axial sequence; and
• the spur gear pairs and gears rotatably connected to the planetary gear set and the planetary gear set and the associated shifting elements can be interchanged in their axial order.

• einem Hybridgetriebe wie zuvor definiert;
• einer Verbrennungsmaschine, die mit der ersten Getriebeeingangswelle verbindbar ist; und
• einer ersten elektrischen Antriebsmaschine, die mit der zweiten Getriebeeingangswelle antriebswirksam verbindbar ist.

The above object is also achieved by a motor vehicle drive train with:

• a hybrid transmission as previously defined;
• an internal combustion engine connectable to the first transmission input shaft; and
• a first electric drive machine which can be connected to the second transmission input shaft in a drivingly effective manner.

The above object is also achieved by a method for operating a motor vehicle drive train as defined above.

• einem Kraftfahrzeug-Antriebsstrang wie zuvor definiert; und
• einem Energiespeicher zum Speichern von Energie zum Versorgen der ersten elektrischen Antriebsmaschine, der zweiten elektrischen Antriebsmaschine und/oder der dritten elektrischen Antriebsmaschine.

The above task is finally solved by a motor vehicle with:

• an automotive powertrain as previously defined; and
• an energy store for storing energy to supply the first electric drive machine, the second electric drive machine and/or the third electric drive machine.

Preferred developments of the invention are described in the dependent claims. It goes without saying that the features mentioned above and those still to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention. In particular, the motor vehicle drive train, the motor vehicle and the method can be designed in accordance with the configurations described for the hybrid transmission in the dependent claims.

A compact hybrid transmission can be created in a technically simple manner 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 machine. An active connection can be designed to be both switchable and non-switchable. In particular, a hybrid transmission for a front transverse arrangement of an internal combustion engine, which is arranged on a wheel axle, can be created. A planetary gear set, which is connected to the second transmission input shaft, a first intermediate shaft and a pair of spur gears to the countershaft, makes it technically easy to set up an EDA mode that enables electrodynamic starting and electrodynamic shifting. At least one ECVT mode can also be set up. Due to the interchangeability of the gears, spur gear pairs and associated shifting elements, a highly variable hybrid transmission can be created that can be technically easily adapted to different installation space requirements. It goes without saying that an optional locking shift element is to be regarded as belonging to the planetary gear set, regardless of the arrangement of the locking shift element in the transmission. Furthermore, switching elements for connecting transmission components are to be regarded as belonging to both transmission components. With the hybrid transmission, the first electric drive machine and the internal combustion engine can preferably be connected parallel to the axis.

In a preferred embodiment, a differential of the output comprises a differential shaft which is designed as a solid shaft and is surrounded at least in sections by the transmission shafts, in particular the first intermediate shaft. An axial length of the differential shaft is greater than an axial length of the first intermediate shaft. The differential shaft completely penetrates the first intermediate shaft. As a result, the hybrid transmission can be advantageously arranged around the differential shaft. A compact drive train can be created.

In a further advantageous embodiment, a planetary gear carrier of the planetary gearset is connected to the countershaft via the pair of spur gears, the sun gear of the planetary gearset being connected to the second transmission input shaft and the ring gear of the planetary gearset being connected to the first intermediate shaft. Alternatively, the planet carrier of the planetary gear set is connected to the countershaft via the pair of spur gears, the ring gear of the planetary gear set being connected to the second transmission input shaft and the sun gear of the planetary gear set being connected to the first intermediate shaft. Through a Connecting the sun gear to the second transmission input shaft and the ring gear to the first intermediate shaft preferably requires only a small support torque to be applied by the first electric drive machine during electrodynamic starting and electrodynamic shifting. Furthermore, the first electric drive machine can be operated as a generator for longer during an electrodynamic start, since the generator operation can be maintained for longer as the driving speed increases. By connecting the ring gear to the second transmission input shaft and the sun gear to the first intermediate shaft, the first electric drive machine can be operated at a low compensating speed during electrodynamic starting or electrodynamic shifting.

In a further advantageous embodiment, the first transmission input shaft can be connected in a drivingly effective manner to a second electric drive machine.

An output shaft of the second electric drive machine preferably includes an electric machine clutch for detachably drivingly connecting the second electric drive machine to the first transmission input shaft. As a result, the second electric drive machine can be used for other tasks when the internal combustion engine is at a standstill. The electric machine clutch is preferably designed as a claw clutch or as a magnetic clutch.

In a further advantageous embodiment, the hybrid transmission includes a locking shift element that is designed to lock the first intermediate shaft. In addition or as an alternative, the hybrid transmission includes a connecting switching element which is designed to connect the second intermediate shaft to the second transmission input shaft in a drivingly effective manner. A planetary gear set element of the planetary gear set can be fixed by a locking shifting element. As a result, a short translation can be set up by means of the planetary gear set for the first electric drive machine. The gear stage created in this way can preferably be used for reversing. This enables a high axle torque in a serial drive mode. Furthermore, there are lower requirements for the maximum driving speed when reversing. It goes without saying that the gear stage created in this way can also be used as a purely electric crawler gear when driving forwards and backwards. This is particularly advantageous in a parking garage where speeds are limited and no internal combustion engine operation is desired. A connection switching element can be used to set up a connection between the first electric drive machine and the internal combustion engine without creating a connection to the output. This condition is commonly known as charge-to-neutral. In this way, in particular, an on-board network can be supplied with power or the internal combustion engine can be cold-started.

In a further advantageous embodiment, the hybrid transmission comprises exactly three gear-forming pairs of spur gears and one pair of driven spur gears. As a result, a light, compact and highly efficient hybrid transmission can be created.

In a further advantageous embodiment, an output of the hybrid transmission includes an output gear, which is arranged with a differential of the output in a wheel set plane and preferably meshes with a differential carrier of the differential. As a result, an axial and/or radial compactness of the hybrid transmission can be further improved. A compactness of the hybrid transmission can preferably be further increased, particularly in combination with arranging the hybrid transmission around the differential shaft.

In a further advantageous embodiment, the first transmission input shaft comprises an internal combustion engine clutch for detachably drivingly connecting the first transmission input shaft to the internal combustion engine. It goes without saying that the internal combustion engine clutch can be designed as a claw shift element or a friction shift element. The combustion engine can be completely decoupled from the hybrid transmission by means of a combustion engine clutch, and a highly efficient, purely electric driving mode can thus be set up using the hybrid transmission. An internal combustion engine clutch in the form of a friction clutch allows a so-called momentum start of the internal combustion engine and can serve as a starting element for the internal combustion engine. The variability and the efficiency of the hybrid transmission, especially in a purely electric driving mode, can be increased by means of an internal combustion engine clutch.

In a further advantageous embodiment, an output gear, a fixed gear of the third pair of spur gears and a hollow shaft, each with a gear of the first pair of spur gears and the second pair of spur gears, are arranged on the countershaft. As a result, high functionality and variability can be achieved with a high compactness of the hybrid transmission.

In a further advantageous embodiment, a first switching element is designed to to connect the first intermediate shaft to the second intermediate shaft in a drivingly effective manner by means of the first pair of spur gears and the second pair of spur gears. In addition or as an alternative, a second shifting element is designed to connect the second intermediate shaft to the countershaft in a drivingly effective manner by means of the first pair of spur gears. Furthermore, additionally or alternatively, a third shifting element is designed to connect the first intermediate shaft to the second intermediate shaft in a drivingly effective manner. Furthermore, additionally or alternatively, a fourth shifting element is designed to block the planetary gear set. With this advantageous arrangement of the shifting elements, three hybrid or four combustion gears, at least one electric gear and two electric CVT modes can be set up with the hybrid transmission. A variable and compact hybrid transmission can be created with which electrodynamic starting and electrodynamic gearshifts for the internal combustion engine are possible.

In a further advantageous embodiment, the switching elements are designed as form-fitting switching elements. Additionally or alternatively, at least two of the switching elements are designed as double switching elements and can be actuated by a double-acting actuator. A highly efficient and cost-effective hybrid transmission can be created using positive-locking shifting elements. The design and operation of the hybrid transmission can be simplified by at least one double shifting element. In particular, a double switching element can be actuated by means of a single actuator, an XY actuator or a shift drum.

In a further advantageous refinement, the motor vehicle drive train comprises a second electric drive machine which can be connected to the first transmission input shaft in a drivingly effective manner. The first electric drive machine and/or the second electric drive machine can be controlled as a starter generator for starting the internal combustion engine. Additionally or alternatively, the first electric drive machine and/or the second electric drive machine can be controlled as a charging generator for charging an energy store. As a result, an efficient motor vehicle drive train can be created. In particular, fuel consumption can be reduced. It goes without saying that an additional starter for the internal combustion engine can be dispensed with. In addition, the second electric drive machine can be used for other functions when the first electric drive machine tows the internal combustion engine or vice versa.

In a further advantageous refinement, an output of the hybrid transmission can be connected in a drivingly effective manner to a first motor vehicle axle, with a second motor vehicle axle comprising an electric axle with a third electric drive machine. As a result, a hybrid drive train with all-wheel drive can be created in a technically simple manner. Furthermore, the motor vehicle drive train can enable shifting without interruption of traction in a technically simple manner, since the electric axle can maintain the traction during shifts in the hybrid transmission. In addition, a fail-safe drive train for a motor vehicle can be created, since a so-called serial driving mode can be set up for the electric drive machine in the event of an exhausted energy store. In the serial driving mode, the electric drive machine is preferably operated as a generator by the internal combustion engine and the energy thus generated is made available to the third electric drive machine.

In a further advantageous embodiment, the first electric drive machine can be controlled as a generator for supplying power to the third electric drive machine in order to set up a serial driving mode. As a result, a highly variable motor vehicle drive train can be created in which, in particular, it is possible to drive and, in particular, to start up electrically even when the energy store is empty.

In a further advantageous embodiment, an electric gear stage is set up by engaging a fourth shifting element. In addition, you can switch from the electric gear to each of the hybrid gears by inserting another shift element. As a result, comfortable shifting in the hybrid transmission can be achieved. In particular, it is possible to change between the hybrid gears without any interruption in tractive force, thus enabling power shifting between the hybrid gears. Furthermore, the internal combustion engine can be started directly in a preferred speed level and the corresponding hybrid gear stage from purely electric driving mode.

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.

The element is preferably connected in a rotationally fixed manner to a static component such as a frame and/or a transmission housing by means of a switching element. It is also conceivable to brake the element to a standstill.

Blocking a planetary gear set includes a drive-effective connection of two gears and/or the planetary gear carrier and a gear wheel of the planetary gear set, so that they rotate together with the same number of revolutions around the same point, preferably the center point of the planetary gear set. When two gear wheels and/or a planetary gear carrier and a gear wheel of the planetary gear set are locked together, the planetary gear set preferably acts like a shaft; in particular, there is no translation in the planetary gear set.

In this context, “connected in a drivingly effective manner” is to be understood in particular as meaning a non-switchable connection between two components, which is provided for permanent transmission of a speed, a torque and/or drive power. The connection can be made either directly or via a fixed transmission. The connection can be made, for example, via a fixed shaft, a toothing, in particular a spur gear toothing and/or a belt device, in particular a traction mechanism.

In this context, "can be connected in a drive-effective manner", "can be connected in a drive-effective manner" or "is designed for drive-effective connection" in particular to mean a switchable connection between two components which, in a closed state, results in a temporary transmission of a speed, a torque and/or or a drive power is provided. In an open state, the switchable connection preferably temporarily transmits essentially no speed, no torque and/or no drive power.

Stationary charging or charging in neutral is to be understood in particular as the operation of the electric drive motor as a generator, preferably when the internal combustion engine is at a standstill, in order to fill an energy storage device and/or feed on-board electronics.

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

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

An internal combustion engine can be, in particular, any machine that can generate a rotary motion by burning a drive medium, such as gasoline, diesel, kerosene, ethanol, liquid gas, LPG, etc. An internal combustion engine can be, for example, an Otto engine, a diesel engine, a Wankel engine or a two-stroke engine.

When driving or crawling in series, an electric drive machine of a motor vehicle is operated as a generator by an internal combustion engine of the motor vehicle. The energy generated in this way 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 the wheels of the motor vehicle by means of an electric drive machine. It goes without saying that the electric drive machine can also be connected by means of a transmission. A traction force can be maintained in whole or in part by means of an electric axle when a gear change takes place in the transmission for a main drive axle. Furthermore, an all-wheel drive functionality can be set up at least partially by means of an electric axle.

An electrodynamic starting element (EDA) causes the speed of the internal combustion engine and the speed of the electric drive unit to be superimposed via one or more planetary gear sets, so that a motor vehicle can be started from a standstill while the internal combustion engine is running, preferably without a friction clutch. In this case, the electric drive machine supports a torque. Preferably, the internal combustion engine can no longer be separated from the transmission by a starting clutch or the like. By using an EDA, the starter, generator and starting clutch or hydrodynamic converter can preferably be omitted. In particular, an EDA is so compact that all components can be accommodated in the standard clutch housing without extending the transmission. The electrodynamic starting element can, for example, be fixed to a softly tuned torsional damper Internal combustion engine and in particular a flywheel of an internal combustion engine. Thus, the electric drive machine and the internal combustion engine can be operated either simultaneously or alternatively. If the motor vehicle stops, the electric drive motor and the internal combustion engine can be switched off. Due to the good controllability of the electric drive unit, a very high starting quality is achieved, which can correspond to that of a drive with a converter clutch.

In a so-called electrodynamic shift (EDS), as with EDA starting, a speed superimposition of the speed of the internal combustion engine and the speed of the electric drive machine takes place via one or more planetary gear sets. At the start of shifting, the torques of the electric drive motor and the internal combustion engine are adjusted so that the shifting element to be designed is load-free. After opening this switching element, the speed is adjusted while maintaining the traction, so that the switching element to be engaged becomes synchronous. After the switching element is closed, the load is shared between the internal combustion engine and the electric drive unit as required, depending on the hybrid operating strategy. The advantage of the electrodynamic shifting method is that the shifting element of the target gear to be shifted is synchronized by the interaction of the electric drive motor and the internal combustion engine, with the electric drive motor preferably being precisely controllable. Another advantage of the EDL shifting process is that a high level of traction can be achieved, since the torques of the internal combustion engine and the electric machine add up in the hybrid transmission.

• 1 eine schematische Draufsicht auf ein Kraftfahrzeug mit einem erfindungsgemäßen Kraftfahrzeug-Antriebsstrang;
• 2 eine schematische Darstellung eines erfindungsgemäßen Hybridgetriebes;
• 3 schematisch die Schaltzustände des Hybridgetriebes gemäß der 2;
• 4 eine weitere Variante eines erfindungsgemäßen Hybridgetriebes;
• 5 schematisch die Schaltzustände des Hybridgetriebes gemäß der 4;
• 6 eine weitere Variante eines erfindungsgemäßen Hybridgetriebes;
• 7 schematisch die Schaltzustände des Hybridgetriebes gemäß der 6;
• 8 eine weitere Variante eines erfindungsgemäßen Hybridgetriebes;
• 9 eine weitere Variante eines erfindungsgemäßen Hybridgetriebes;
• 10 schematisch die Schaltzustände des Hybridgetriebes gemäß der 8 und 9;
• 11 eine weitere Variante eines erfindungsgemäßen Hybridgetriebes;
• 12 schematisch die Schaltzustände des Hybridgetriebes gemäß der 11;
• 13 eine weitere Variante eines erfindungsgemäßen Hybridgetriebes;
• 14 eine weitere Variante eines erfindungsgemäßen Hybridgetriebes;
• 15 eine weitere Variante eines erfindungsgemäßen Hybridgetriebes;
• 16 eine weitere Variante eines erfindungsgemäßen Hybridgetriebes;
• 17 eine weitere Variante eines erfindungsgemäßen Hybridgetriebes;
• 18 eine weitere Variante eines erfindungsgemäßen Hybridgetriebes;
• 19 eine weitere Variante eines erfindungsgemäßen Hybridgetriebes;
• 20 eine weitere Variante eines erfindungsgemäßen Hybridgetriebes; und
• 21 schematisch die Schaltzustände eines reinen Elektro-Betriebs des Hybridgetriebes gemäß der 8, 9 und 13 bis 20.

The invention is described and explained in more detail below using a few selected exemplary embodiments in connection with the accompanying drawings. Show it:

• 1 a schematic plan view of a motor vehicle with a motor vehicle drive train according to the invention;
• 2 a schematic representation of a hybrid transmission according to the invention;
• 3 schematically the switching states of the hybrid transmission according to the 2 ;
• 4 another variant of a hybrid transmission according to the invention;
• 5 schematically the switching states of the hybrid transmission according to the 4 ;
• 6 another variant of a hybrid transmission according to the invention;
• 7 schematically the switching states of the hybrid transmission according to the 6 ;
• 8th another variant of a hybrid transmission according to the invention;
• 9 another variant of a hybrid transmission according to the invention;
• 10 schematically the switching states of the hybrid transmission according to the 8th and 9 ;
• 11 another variant of a hybrid transmission according to the invention;
• 12 schematically the switching states of the hybrid transmission according to the 11 ;
• 13 another variant of a hybrid transmission according to the invention;
• 14 another variant of a hybrid transmission according to the invention;
• 15 another variant of a hybrid transmission according to the invention;
• 16 another variant of a hybrid transmission according to the invention;
• 17 another variant of a hybrid transmission according to the invention;
• 18 another variant of a hybrid transmission according to the invention;
• 19 another variant of a hybrid transmission according to the invention;
• 20 another variant of a hybrid transmission according to the invention; and
• 21 schematically shows the switching states of a purely electric operation of the hybrid transmission according to 8th , 9 and 13 until 20 .

In 1 a motor vehicle with a motor vehicle drive train 12 is shown schematically. The motor vehicle drive train 12 has a first electric drive machine 14 , an internal combustion engine 16 , a hybrid transmission 18 and an optional second electric drive machine 20 . The hybrid transmission 18 is connected to a front axle of the motor vehicle 10 . In the example shown, the motor vehicle drive train 12 also includes an optional electric axle with a third electric drive machine 24 which is connected to a rear axle of the motor vehicle 10 . It goes without saying that the reverse connection can also take place, so that the hybrid transmission 18 is connected to the rear axle of the motor vehicle 10 and the front axle of the motor vehicle 10 comprises the electric axle. By means of the motor vehicle drive train 12 drive power of the first electric drive machine 14, the internal combustion engine 16, the optional second electric drive machine 20 and / or optional third electric drive machine 24 fed to the wheels of the motor vehicle 10. The motor vehicle 10 also has an energy store 22 to store energy that is used to supply the first electric drive machine 14, the optional second electric drive machine 20 and/or the optional third electric drive machine 24.

2 shows a first variant of a hybrid transmission 18 according to the invention in a motor vehicle drive train 12. The hybrid transmission 18 has a first transmission input shaft 26 and a second transmission input shaft 28, which are designed to transmit drive power of the drive machines in the hybrid transmission 18. The hybrid transmission 18 also has a first intermediate shaft 30 and a second intermediate shaft 32 . The aforementioned gear shafts 26, 28, 30, 32 are designed as hollow shafts.

The first transmission input shaft 26 has a torsional vibration damper and is drivingly connected to a crankshaft 34 of the internal combustion engine 16 (not shown) via the torsional vibration damper. The second transmission input shaft 28 is drivingly connected to the first electric drive machine 14 via a fixed wheel and a chain.

The hybrid transmission 18 also includes a countershaft 36 on which a hollow shaft 38 is arranged. Furthermore, the hybrid transmission 18 includes a planetary gear set RS and a total of three gear-forming pairs of spur gears, which are denoted by ST1 to ST3.

The first transmission input shaft 26 is drivingly connected, preferably by means of a chain, to a fixed wheel arranged on the second intermediate shaft 32 . Furthermore, the hybrid transmission 18 in the example shown includes four shifting elements A to D.

A sun gear of the planetary gear set RS is drivingly connected to the second transmission input shaft 28 . A planetary gear carrier of the planetary gearset RS is drivingly connected to a spur gear of the third pair of spur gears ST3 , the other gearwheel of the third pair of spur gears ST3 being designed as a fixed gear and being assigned to the countershaft 36 .

A ring gear of the planetary gearset RS is drivingly connected to the first intermediate shaft 30 .

The first pair of spur gears ST1 has a fixed gear which is arranged on the hollow shaft 38 in a drivingly effective manner. Another fixed wheel of the first pair of spur gears ST1 is arranged on the second intermediate shaft 32 .

A gear of the second pair of spur gears ST2 is also arranged on the hollow shaft 38 . The second pair of spur gears ST2 also includes an idler gear, which is arranged on the first intermediate shaft 30 and can be drivingly connected to it by engaging the first shifting element A.

The hollow shaft 38 can be drivingly connected to the countershaft 36 by inserting a second shifting element B.

The second intermediate shaft 32 can be drivingly connected to the first intermediate shaft 30 by inserting a third shifting element C.

By inserting a fourth shifting element D, the planetary gear set RS can be blocked by the ring gear of the planetary gear set RS being connected in a drivingly effective manner to the sun gear of the planetary gear set RS.

The switching elements A to D are preferably designed as unsynchronized, for example claw switching elements. Furthermore, the first switching element A and the third switching element C are combined to form a double switching element.

A fourth pair of spur gears, an output pair of spur gears ST4 , is also arranged on the countershaft 36 and transmits drive power from the hybrid transmission 18 to an output 40 of the hybrid transmission 18 . The output 40 preferably comprises a differential with a differential shaft, the differential shaft being designed as a solid shaft and penetrating the hybrid transmission 18 and in particular the first intermediate shaft 30 completely. In other words, the hybrid transmission 18 can be arranged around the differential shaft.

The differential of the output 40 can be designed, for example, as a ball differential, spur gear differential or planetary gear differential.

The hybrid transmission 18 is therefore preferably arranged around a differential shaft on a front axle, with the internal combustion engine 16 and the first electric drive machine 14 and the second electric drive machine 20 being arranged axis-parallel thereto.

In 3 are schematically the switching states of the hybrid transmission 18 according to 2 shown in a switching matrix 42 .

The hybrid gears H1 to H3, an electric gear E2 and two electrodynamic superposition states ECVT1 and ECVT2 are shown in a first column of the switching matrix 42 . The shifting states of the shifting elements A to D are shown in the second to fifth columns, with an “X” meaning that the respective shifting element is closed, that is to say it connects the associated transmission components with one another in a drivingly effective manner. If there is no entry, it can be assumed that the corresponding switching element is open, ie is not transmitting any drive power.

To set up the first hybrid gear stage H1, the first switching element A and the fourth switching element D are to be closed.

Closing the second switching element B and the fourth switching element D establishes the second hybrid gear stage H2.

The third hybrid gear stage H3 can be set up by closing the third switching element C and the fourth switching element D.

The electric gear stage E2 can be set up by closing the fourth switching element D.

A first electrodynamic superimposition state ECVT1 can be set up by closing the first switching element A.

Closing the third switching element C establishes a second electrodynamic superimposition state ECVT2.

The following functions can be set up with the second electric drive machine 20, which is preferably designed as a high-voltage starter generator. It is possible to start the internal combustion engine 16 from a purely electric drive. The vehicle electrical system can be supplied by the second electric drive machine 20 operated as a generator. Furthermore, serial crawling or driving both forwards and backwards is possible. In addition, the second electric drive machine 20 can support the internal combustion engine 16 in controlling the speed, for example when coupling and when shifting gears. The internal combustion engine 16 can be coupled in all hybrid gears H1 to H3 when the first electric drive machine 14 uses the electric gear E2. Furthermore, the second electric drive machine 20 can support the relief of the first to third shifting elements A to C by the second electric drive machine 20 working as a generator. The energy generated in this way can be used by the first electric drive machine 14 to support traction.

The following functions can be set up by means of the first electric drive machine 14 . An electric vehicle drive can be set up for starting and driving both forwards and backwards. The traction force can be supported in circuits for the internal combustion engine 16 . The first electric drive machine 14 can maintain the tractive force via the electric gear stage E2 when there is a change in the first, second or third shifting element A, B, C.

A power shift from a hybrid gear stage H1 to a hybrid gear stage H2 can take place as follows. In the initial state, the hybrid gear stage H1 is engaged, and consequently the first switching element A and the fourth switching element D are closed. There is a load reduction on the first switching element A and a simultaneous load increase on the first electric drive machine 14. The load reduction can take place in that the internal combustion engine and the second electric drive machine 20 reduce the torque or when the second electric drive machine 20 compensates the torque of the internal combustion engine 16 as a generator , So that the sum of the moments of the internal combustion engine 16 and the second electric drive machine 20 is close to zero or equal to zero. Then the first switching element A is opened. The speed of the internal combustion engine 16 and the second electric drive machine 20 is lowered, so that the second switching element B becomes synchronous. For this purpose, for example, the second electric drive machine 20 can work as a generator or the internal combustion engine 16 can go into overrun mode. The second switching element B, which is then synchronous, can then be inserted.

Pure electric driving can be done as follows. By closing the fourth shifting element D, the planetary gear set RS is blocked. An electric gear E2 is engaged, with which the entire speed range of the vehicle can be covered.

If the first shifting element A is closed, an electrodynamic superposition occurs on the planetary gear set RS, in which the first electric drive machine 14 on the sun gear of the planetary gear set RS supports the torque of the internal combustion engine 16 acting on the ring gear. A state is created that enables electrodynamic drive-off, EDA, forward. From this EDA mode or from the electrodynamic superimposition mode ECVT1, the internal combustion engine 16 can reach the first hybrid gear H1 because the first shifting element A and the fourth shifting element D are closed there.

The traction that can be achieved by the internal combustion engine 16 is higher than in the first hybrid gear stage H1, since the translation of the planetary gear set RS is effective. The ECVT1 state can be referred to as a power-split CVT state because part of the power of the internal combustion engine 16 can be transmitted mechanically via the planetary gear set RS and part via the first electric drive machine 14 and/or the second electric drive machine 20.

It goes without saying that the optional third electric drive machine 24, if present, is included in the power flow.

In the third hybrid gear stage H3, the fourth switching element D can be opened. Consequently, only the third switching element C is closed. A second electrodynamic superimposition state ECVT2 arises, in which the first electric drive machine 14 on the sun gear of the planetary gear set RS supports the torque of the internal combustion engine 16 acting on the ring gear. In this state, a speed adjustment of the internal combustion engine speed can be compensated for by the first electric drive machine 14 . For example, the speed of the internal combustion engine 16 can be reduced and efficient operating points can be selected for the drive engines. Instead of a speed reduction, the second electrodynamic superimposition state ECVT2 can also be used to spontaneously increase the speed of the internal combustion engine speed, for example as an alternative to a downshift. The traction that can be achieved by the internal combustion engine 16 is higher than in the third hybrid gear stage H3, since the translation of the planetary gear set RS is effective. The second electrodynamic superposition state ECVT2 is a power-split CVT mode.

In 4 Another variant of a hybrid transmission 18 according to the invention is shown. In contrast to the in 2 shown embodiment includes the hybrid transmission 18 according to 4 a fifth switching element E, which is designed to fix the first intermediate shaft 30 and thus the ring gear of the planetary gear set RS, ie to connect it to a non-rotatable transmission component, for example a transmission housing.

The fifth switching element E is combined with the fourth switching element D to form a double switching element.

By locking the ring gear of the planetary gear set RS, a short transmission ratio is created on the planetary gear set RS for the first electric drive machine 14. The additional electric gear stage E1 that is created in this way is preferably used for reversing. In reverse, a high axle torque is possible in a serial drive mode in this way. Furthermore, when reversing, lower demands are made on the maximum driving speed. It goes without saying that the further electric gear stage E1 can also be used as a purely electric crawler gear when driving forwards and backwards.

In 5 are the switching states of the hybrid transmission according to the 4 shown in a switching matrix 44 . The switching matrix 44 is essentially analogous to that in 3 switching matrix 42 shown. The switching matrix 44 includes the switching state for the further electric gear stage E1. To set up this additional electric gear stage E1, the locking switching element E must be closed.

In 6 Another variant of a hybrid transmission 18 according to the invention is shown. In contrast to the in 2 shown embodiment of a hybrid transmission 18 comprises the hybrid transmission 18 according to 6 a connecting switching element L, which is designed to driveally connect the second transmission input shaft 28 to the second pair of spur gears ST2. Consequently, by engaging the connecting switching element L, the first electric drive machine 14 is drivingly connected to the crankshaft 34 of the internal combustion engine 16 via the second transmission input shaft 28, the second pair of spur gears ST2, the hollow shaft 38, the first pair of spur gears ST1, the second intermediate shaft 32 and the first transmission input shaft 26 . Consequently, a connection between the internal combustion engine 16 and the first electric drive machine 14 can be set up in such a way that there is no connection to the output 40 . This state is referred to as charge-to-neutral LiN.

In 7 are the switching states of the hybrid transmission according to the 6 shown in a switching matrix 46 . The switching matrix 46 is analogous to that in 3 shown switching matrix 42 formed, but also includes the state charge-in-neutral LiN. As already described above, the connection switching element L is to be closed in order to set up the charge-in-neutral LiN state.

In 8th Another variant of a hybrid transmission 18 according to the invention is shown. In contrast to the in 4 The hybrid transmission 18 shown includes the first transmission input shaft 26 an internal combustion engine clutch K0, which is designed to releasably connect the crankshaft 34 of the internal combustion engine 16, not shown, to the first transmission input shaft 26 in a drivingly effective manner. Consequently, by opening the internal combustion engine clutch K0, the internal combustion engine 16 can be separated from the hybrid transmission 18 to be separated. In the example shown, the internal combustion engine clutch K0 is designed as a positive clutch, for example a claw shift element.

In 9 Another variant of a hybrid transmission 18 according to the invention is shown. In contrast to the in 8th shown embodiment, the internal combustion engine clutch K0 is designed as a friction shift element. As a result, the internal combustion engine clutch K0 can also be opened under load. This is particularly advantageous in the event of emergency braking or a malfunction of the internal combustion engine 16. Furthermore, the internal combustion engine clutch K0 can also be closed when there is a speed difference, so that a so-called momentum start of the internal combustion engine 16 is possible.

It is understood that in the two embodiments according to 8th and 9 the locking switching element E can be regarded as optional. Furthermore, the embodiments according to 8th and 9 can also be designed with a connecting switching element L or with only four switching elements A to D.

In 10 are the switching states of the hybrid transmission according to the 8th and 9 shown in a switching matrix 48 . The switching matrix 48 is essentially analogous to that in 5 switching matrix 44 shown. In the switching matrix 48, the switching states of the internal combustion engine clutch K0 are also shown in a first column, with the internal combustion engine clutch K0 being closed in all hybrid gear stages H1 to H3 and in both electrodynamic superimposition states ECVT1, ECVT2. How re 9 already described, in a purely electric operation of the electric gear stage E2 or the further electric gear stage E1, a momentum start of the internal combustion engine 16 can take place. In this case, the internal combustion engine clutch K0 would have to be closed. This is represented in the switching matrix 48 by the "X" in brackets. It goes without saying that the internal combustion engine clutch K0 is open in purely electric driving mode.

In 11 Another variant of a hybrid transmission 18 according to the invention is shown. In contrast to the in 4 The embodiment shown, the hybrid transmission 18 includes an electric machine clutch K1, which is designed to detachably drive the second electric drive machine 20 to the first transmission input shaft 26 to connect. As a result, the second electric drive machine 20 can also be used for other tasks, in particular when the internal combustion engine 16 is at a standstill, such as for example to drive an air conditioning compressor.

The electric machine clutch K1 is preferably designed as a claw clutch and is preferably located on an output shaft of the second electric drive machine 20 and decouples the toothed or chain wheel arranged there, via which a connection to the first transmission input shaft 26 is set up.

The torque to be supported on the electric machine clutch K1 is significantly lower than the torque to be supported on the internal combustion engine clutch K0, since only the torque of the second electric drive machine 20 has to be supported. As a result, the shifting force of the electric machine clutch K1 is lower. Instead of a claw clutch, the electric machine clutch K1 can also be designed as a magnetic clutch, for example. A disadvantage of the in 11 The embodiment shown is that the internal combustion engine 16 can no longer be decoupled from the hybrid transmission 18 .

In 12 are the switching states of the hybrid transmission according to the 11 shown in a switching matrix 50 . The switching matrix is analogous to the switching matrix 48 according to FIG 10 , the switching states of the electric machine clutch K1 being shown instead of the switching states of the internal combustion engine clutch K0. The electric machine clutch K1 can be opened or closed in each of the switching states, depending on whether the second electric drive machine 20 is to transmit drive power or is to be operated as a generator or not in the respective switching state.

In 13 Another variant of the hybrid transmission 18 according to the invention is shown. In contrast to the in 8th In the embodiment shown, the first switching element A and the associated loose wheel of the second pair of spur gears ST2 are arranged on the hollow shaft 38 . It goes without saying that the other gear of the second pair of spur gears ST2 is designed as a fixed gear and is assigned to the first intermediate shaft 30 . The first switching element A is combined with the second switching element B to form a double switching element. The third shifting element C is designed as a single shifting element and is arranged on the outside of the transmission. In the embodiment shown, the gears of the first pair of spur gears ST1 and the second pair of spur gears ST2, which are arranged on countershaft 36, are designed as idler gears, with the first shifting element A being able to set up a drive-effective connection of these two idler gears without closing them with countershaft 36 associate.

In 14 Another variant of a hybrid transmission 18 according to the invention is shown. In contrast to the in 8th shown execution form, the second switching element B is arranged on the outside of the transmission. As a result, in the hybrid transmission 18, three shift gates that are axially offset from one another can be created for the shifting elements A to E. This allows a spatially advantageous arrangement of the shift forks. Furthermore, no switching element is arranged between the third pair of spur gears ST3 and the second pair of spur gears ST2 on the countershaft 36 .

In 15 Another variant of a hybrid transmission 18 according to the invention is shown. In contrast to the in 8th shown embodiment are wheel set planes of the two arranged on the second intermediate shaft 32 gears swapped in the axial direction. In other words, a connection of the first transmission input shaft 26 to the second intermediate shaft 32 moves to an outside of the transmission. This has the advantage that a chain for connecting the first transmission input shaft 26 to the second intermediate shaft 32 can be guided past the countershaft 36, regardless of a spatial pivoting angle of the countershaft 36.

In 16 Another variant of a hybrid transmission 18 according to the invention is shown. In contrast to the in 15 embodiment shown, the gear planes of the first pair of spur gears ST1 and the second pair of spur gears ST2 are swapped. The second pair of spur gears ST2 is arranged on the outside of the transmission. Seen from this outside, ie from right to left in the figure, the order of the transmission components is as follows. First the second pair of spur gears ST2 is arranged in the hybrid transmission 18, then the double shifting element comprising the first shifting element A and the third shifting element C, then the gearwheel for connecting the first transmission input shaft 26 and finally the first pair of spur gears ST1.

The remaining transmission components are arranged in the hybrid transmission 18 analogously to the previous embodiments.

In 17 Another variant of a hybrid transmission 18 according to the invention is shown. In contrast to the in 8th shown embodiment, the wheel set levels of the third pair of spur gears ST3 and the planetary gear set RS are swapped. The third spur gear pair ST3 consequently moves next to the output spur gear pair ST4 or next to the output 40. The planetary gear set RS is arranged between the third spur gear pair ST3 and a connecting gear wheel for connecting the first electric drive machine 14. This has the advantage that the gear of the third pair of spur gears ST3 assigned to the planetary gear carrier of the planetary gearset RS can be arranged on a first hollow shaft level of the hybrid transmission 18 .

In 18 Another variant of a hybrid transmission 18 according to the invention is shown. In contrast to the in 8th shown embodiment, the double switching element is arranged comprising the first switching element A and the third switching element C on a transmission outside. It goes without saying that the idler gear of the second pair of spur gears ST2 arranged on the first intermediate shaft 30 is guided by means of a hollow shaft up to the double shifting element comprising the first shifting element A and the third shifting element C, with the second intermediate shaft 32 being arranged around this hollow shaft.

In 19 Another variant of a hybrid transmission 18 according to the invention is shown. In contrast to the in 18 shown embodiment, the wheel set planes of the first pair of spur gears ST1 and the second pair of spur gears ST2 are swapped. As a result, the idler gear of the second pair of spur gears ST2, which is arranged on the first intermediate shaft 30, no longer has to be guided to the double shifting element comprising the first shifting element A and the third shifting element C by means of a hollow shaft that runs through the second intermediate shaft 32.

In 20 Another variant of a hybrid transmission 18 according to the invention is shown. In contrast to the in 8th In the embodiment shown, the second switching element B is arranged on a transmission outside of the hybrid transmission 18 . Furthermore, the double shifting element including the fourth shifting element D and the locking shifting element E is arranged on a side of the hybrid transmission 18 opposite to the arrangement side of the second shifting element B on the first intermediate shaft 30 . A connecting gear wheel for connecting the first electric drive machine 14 is arranged axially adjacent to the double shifting element comprising the fourth shifting element D and the locking shifting element E. The third spur gear ST3 is arranged adjacent to this connection gear. The planetary gear set RS is arranged adjacent to this.

In 21 In a switching matrix 52, the switching states for all of the above-mentioned embodiments of hybrid transmissions 18 with an internal combustion engine clutch K0 and a fifth switching element E, the second switching element B being designed as a single switching element, are shown. In these specific embodiments, a total of four mechanical gears ME1, EZ1, ME2, EZ2 can be engaged for the first electric drive machine 14. Starting the internal combustion engine 16 in two of the gears EZ1 and EZ2 is only possible with an interruption in traction.

An electric gear stage ME1 can be set up by closing the second switching element B and the locking switching element E.

An electric gear stage EZ1 can be set up by closing the first switching element A and the second switching element B.

An electric gear stage ME2 can be set up by closing the second switching element B and the fourth switching element D.

Closing the second switching element B and the third switching element C establishes an electric gear stage EZ2.

It goes without saying that in the embodiments of hybrid transmissions 18 shown above, the locking shifting element E and the connecting shifting element L as well as the internal combustion engine clutch K0 and the electric machine clutch K1 are to be regarded as optional. All of the embodiments shown can consequently be created without the above-mentioned components, with a correspondingly reduced range of functions having to be expected.

The internal combustion engine 16 can be connected to the hybrid transmission 18 for example via a chain or via a wheel chain. Likewise, the first electric drive machine 14 can be connected via a chain or a wheel chain. The same applies to the second electric drive machine 20, which can also be arranged coaxially to the crankshaft of the internal combustion engine 16.

The differential can consist of a spur gear, which engages from the countershaft 36 on a ball differential on a transmission main axis. It goes without saying that the differential can also consist of a torque-increasing planetary gear set and a ball differential. Instead of the ball differential, a spur gear differential or other differential systems such as an integrated differential which can achieve both torque increase and differential action may be used.

The fourth shifting element D is used to block the planetary gearset RS. For blocking, any two shafts of the RS planetary gear set can be connected to one another in a torque-proof manner, so that the entire planetary gear set unit rotates at the same speed. In addition to the variants shown, in which the fourth shifting element D can effectively connect the sun gear and the ring gear of the planetary gearset RS, the fourth shifting element D could also connect the planetary gear carrier and the sun gear or the planetary gear carrier and the ring gear of the planetary gearset RS.

In the embodiments shown, a planetary gear carrier of the planetary gear set RS is connected to the countershaft 36 via a pair of spur gears, the sun gear of the planetary gear set RS being connected to the second transmission input shaft 28 and the ring gear of the planetary gear set RS being connected to the first intermediate shaft 30. It goes without saying that with regard to the ring gear and sun gear, the planetary gear set RS can also be connected in an exchanged manner, with the ring gear of the planetary gear set RS being connected to the second transmission input shaft 28 and the sun gear of the planetary gear set RS being connected to the first intermediate shaft 30.

The invention has been comprehensively described and explained with reference to the drawings and the description. The description and explanation are intended to be exemplary and not limiting. 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 upon a study of the drawings, the disclosure, and the claims that follow.

In the claims, the words "comprising" and "having" do not exclude the presence of other elements or steps. The undefined article "a" or "an" does not exclude the presence of a plural. A single element or unit can perform the functions of several of the units recited in the claims. The mere naming of some measures in several different dependent patent claims should not be understood to mean that a combination of these measures cannot also be used to advantage. Reference signs in the claims are not to be understood as restrictive. A method for operating a motor vehicle drive train 12 can be implemented, for example, in the form of a computer program that is executed on a control device for motor vehicle drive train 12 . A computer program may be stored/distributed on a non-volatile medium, such as an optical memory or a solid state drive (SSD). A computer program may be distributed with and/or as part of hardware, for example via the Internet or via wired or wireless communication systems. Reference signs in the claims are not to be understood as restrictive.

Reference List

10

motor vehicle

12

automotive powertrain

14

first electric drive machine

16

combustion engine

18

hybrid transmission

20

second electric drive machine

22

energy storage

24

third electric drive machine

26

first transmission input shaft

28

second transmission input shaft

30

first intermediate wave

32

second intermediate shaft

34

crankshaft

36

countershaft

38

hollow shaft

40

downforce

42, 44, 46, 48, 50, 52

switching matrix

A to D

switching elements

E

locking switching element

L

connection switching element

K0

internal combustion engine clutch

K1

electric machine clutch

ST1-ST3

spur gear pairs

ST4

Output spur gear pair

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102013215114 A1 [0006]

Claims (18)

Hybrid transmission (18) for a motor vehicle drive train (12) of a motor vehicle (10), with: a first transmission input shaft (26) for operatively connecting the hybrid transmission to an internal combustion engine (16) of the motor vehicle; a second transmission input shaft (28) for operatively connecting the hybrid transmission to a first electric drive machine (14) of the motor vehicle; a first intermediate shaft (30); a second intermediate shaft (32) drivingly connected to the first transmission input shaft; a countershaft (36); Spur gear pairs (ST1, ST2, ST3) arranged in several wheel set planes for forming gear stages; a plurality of gear shifting devices with shifting elements (A, B, C, D) for engaging the gear stages; a planetary gear set (RS), which is connected to the second transmission input shaft, the first intermediate shaft and via a pair of spur gears to the countershaft; and an output (40), wherein the gears, pairs of spur gears and the associated switching elements assigned to the second intermediate shaft can be interchanged in their axial sequence; and the spur gear pairs and gears rotatably connected to the planetary gear set and the planetary gear set and the associated shifting elements can be interchanged in their axial sequence. Hybrid transmission (18) after claim 1 , wherein a differential of the output (40) comprises a differential shaft which is designed as a solid shaft and is surrounded at least in sections by the transmission shafts (28, 30, 32), in particular the first intermediate shaft, with an axial length of the differential shaft being greater than one axial length of the first intermediate shaft and the differential shaft completely penetrates the first intermediate shaft. Hybrid transmission (18) according to one of the preceding claims, wherein a planetary gear carrier of the planetary gear set (RS) is connected via the spur gear pair to the countershaft (36); the sun gear of the planetary gear set is connected to the second transmission input shaft (28) and the ring gear of the planetary gear set is connected to the first intermediate shaft (30); or the ring gear of the planetary gear set is connected to the second transmission input shaft and the sun gear of the planetary gear set is connected to the first intermediate shaft. Hybrid transmission (18) according to one of the preceding claims, wherein the first transmission input shaft (26) can be drivingly connected to a second electric drive machine (20) and preferably an output shaft of the second electric drive machine (20) has an electric machine clutch (K1) for the detachable driving connection of the second includes electric drive machine with the first transmission input shaft (26). Hybrid transmission (18) according to any one of the preceding claims, comprising: a locking switching element (E) which is designed to lock the first intermediate shaft (30); and or a connecting switching element (L), which is designed to drive the second intermediate shaft (32) to the second transmission input shaft (28) to connect. Hybrid transmission (18) according to one of the preceding claims, wherein the hybrid transmission comprises exactly three gear-forming spur gear pairs (ST1, ST2, ST3) and one output spur gear pair (ST4). Hybrid transmission (18) according to one of the preceding claims, wherein the output (40) of the hybrid transmission comprises an output gear which is arranged with a differential of the output in a wheel set plane and preferably meshes with a differential carrier of the differential. Hybrid transmission (18) according to one of the preceding claims, wherein the first transmission input shaft (26) comprises an internal combustion engine clutch (K0) for releasably drivingly connecting the first transmission input shaft to the internal combustion engine (16). Hybrid transmission (18) according to one of the preceding claims, wherein an output gear, a fixed gear of the third pair of spur gears and a hollow shaft (38) each having a gear of the first pair of spur gears (ST1) and the second pair of spur gears (ST2) are arranged on the countershaft (36). . Hybrid transmission (18) according to one of the preceding claims, wherein a first shifting element (A) is designed to drive the first intermediate shaft (30) to the second intermediate shaft (32) by means of the first pair of spur gears (ST1) and the second pair of spur gears (ST2). associate; a second switching element (B) is designed to connect the second intermediate shaft to the countershaft (36) in a drivingly effective manner by means of the first pair of spur gears; a third switching element (C) is designed to drivingly connect the first intermediate shaft to the second intermediate shaft; and or a fourth switching element (D) is designed to block the planetary gear set (RS). Hybrid transmission (18) according to one of the preceding claims, wherein the shifting elements (A, B, C, D, E, L) are designed as positive shifting elements; and/or at least two of the switching elements are designed as a double switching element and can be actuated by a double-acting actuator. Motor vehicle drive train (12) for a motor vehicle (10), with: a hybrid transmission (18) according to any one of the preceding claims; an internal combustion engine (16) connectable to the first transmission input shaft (26); and a first electric drive machine (14) which can be connected to the second transmission input shaft (28) in a drivingly effective manner. Motor vehicle drive train (12) after claim 12 , With a second electric drive machine (20), which is drivingly connected to the first transmission input shaft (26); wherein the first electric drive machine (14) and/or the second electric drive machine (20) can be controlled as a starter generator for starting the internal combustion engine (16); and/or can be controlled as a charging generator for charging an energy store (22). Motor vehicle drive train (12) after claim 12 or 13 , wherein an output (40) of the hybrid transmission (18) with a first motor vehicle axle is drivingly connected and a second motor vehicle axle comprises an electric axle with a third electric drive motor (24). Motor vehicle drive train (12) after Claim 14 , wherein the first electric drive machine (14) can be controlled as a generator for supplying the third electric drive machine (24) in order to set up a serial driving mode. Method for operating a motor vehicle drive train (12) according to one of Claims 12 until 15 . procedure after Claim 16 , wherein an electric gear stage (E2) is set up by engaging a fourth switching element (D); and changing from the electric gear stage (E2) to each of the hybrid gear stages (H1, H2, H3) by engaging a further switching element (A, B, C). Motor vehicle (10) comprising: a motor vehicle powertrain (12) according to any one of Claims 12 until 15 ; and an energy store (22) for storing energy to supply the first electric drive machine (14), the second electric drive machine (20) and/or the third electric drive machine (24).

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