Compact hybrid transmission

Abstract

Hybrid transmission (18) for a motor vehicle powertrain (12) of a motor vehicle (10), comprising: a first transmission input shaft (24) for connecting the hybrid transmission (18) with an internal combustion engine (16) of the motor vehicle (10); a second transmission input shaft (26) for connecting the hybrid transmission (18) with a first electric drive motor (14) of the motor vehicle (10); an output shaft (28) for connecting the hybrid transmission (18) with an output (30); a planetary gear set (RS) which is non-switchable connected to the first transmission input shaft (24) and the output shaft (28); Spur gear pairs (ST1, ST2, ST3) arranged in several gear set planes to form gear steps; and several gearshift devices with shifting elements (A, B, C, D, E) for engaging gear stages, wherein a first spur gear pair (ST1) of the spur gear pairs (ST1, ST2, ST3) is assigned to form gear stages of the first transmission input shaft (24); a second pair of spur gears (ST2) of the spur gear pairs (ST1, ST2, ST3) is assigned to form gear stages of the first transmission input shaft (24) and the second transmission input shaft (26); a third spur gear pair (ST3) of the spur gear pairs (ST1, ST2, ST3) is assigned to form gear stages of the second transmission input shaft (26); and the first transmission input shaft (24) and the second transmission input shaft (26) are arranged coaxially to each other, wherein a planet carrier of the planet gear set (RS) is effectively connected to the output shaft (28); the sun gear of the planetary gear set (RS) is connected to the first transmission input shaft (24) by means of the first spur gear pair (ST1) of the spur gear pairs (ST1, ST2, ST3) to form the gear stages, and the ring gear of the planetary gear set (RS) can be connected to the first transmission input shaft (24) or the second transmission input shaft (26) by means of the second spur gear pair (ST2) of the spur gear pairs (ST1, ST2, ST3) to form the gear stages; or the ring gear of the planetary gear set (RS) is connected to the first transmission input shaft (24) by means of the first spur gear pair (ST1) of the spur gear pairs (ST1, ST2, ST3) to form the gear stages and the sun gear of the planetary gear set (RS) can be connected to the first transmission input shaft (24) or the second transmission input shaft (26) by means of the second spur gear pair (ST2) of the spur gear pairs (ST1, ST2, ST3) to form the gear stages.

Description

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

[0002] Vehicles are increasingly being equipped with hybrid drives, meaning they have at least two different drive sources. Hybrid drives can contribute to reducing fuel consumption and pollutant emissions. Powertrains with an internal combustion engine and one or more electric motors, configured as parallel hybrids or mixed hybrids, have largely become the standard. In such hybrid drives, the internal combustion engine and the electric motor are arranged in a largely parallel power flow. This allows for both a superposition of the drive torques and control using either the internal combustion engine or the electric motor alone. Since the drive torques of the electric motor and the internal combustion engine can add up depending on the control configuration, a comparatively smaller internal combustion engine and / or its temporary deactivation are possible.This allows for a significant reduction in CO2 emissions without any noticeable loss of performance or comfort. The possibilities and advantages of an electric drive can thus be combined with the range, performance, and cost advantages of internal combustion engines.

[0003] One disadvantage of the aforementioned hybrid drives is their generally more complex design, as both drive sources preferably transmit power to a single drive shaft via a single transmission. This makes such transmissions typically complex and expensive to produce. Reducing the complexity of a hybrid transmission's design usually comes at the cost of reduced versatility.

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

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

[0006] From the patent application DE 10 2013 215 114 A1, a hybrid drive for a motor vehicle is known, comprising an internal combustion engine with a drive shaft, an electric machine with a rotor that can be operated as a motor and as a generator, an automated transmission designed in a reduction gear with an input shaft and at least one output shaft, and a planetary gear set with two input elements and one output element.In this hybrid drive system, the superimposed transmission is arranged coaxially above a free end of the output shaft. The first input element of the superimposed transmission is rotationally fixed to a hollow shaft arranged coaxially above the output shaft. This hollow shaft can be rotationally fixed to a loose gear of the immediately adjacent axially adjacent spur gear stage of the transmission via a coupling element for coupling the combustion engine. Furthermore, a bypass element allows for rotationally fixed connection of the second input element or the output element of the superimposed transmission to bypass the superimposed transmission. The second input element of the superimposed transmission is permanently connected to the rotor of the electric motor, and the output element of the superimposed transmission is rotationally fixed to the output shaft.

[0007] Further hybrid transmissions are known from the published patent applications DE 10 2019 212 141 A1, DE 10 2020 205 099 A1 and DE 10 2008 037 408 A1 as well as from the subsequently published documents DE 10 2022 201 155 A1, DE 10 2021 213 312 A1 and DE 10 2021 213 678 A1.

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

[0009] This task is solved by a hybrid transmission for a motor vehicle powertrain of a motor vehicle with: a first transmission input shaft for connecting the hybrid transmission to an internal combustion engine of the motor vehicle; a second transmission input shaft for effectively connecting the hybrid transmission to a first electric drive motor of the motor vehicle; an output shaft for effectively connecting the hybrid transmission to an output; a planetary gear set that is non-switchable and effectively connected to the first transmission input shaft and the output shaft; Spur gear pairs arranged in several gear set planes to form gear stages; and several gearshift devices with shifting elements for engaging gear stages, wherein a first spur gear pair of the spur gear pairs is assigned to the first transmission input shaft for forming gear stages; a second pair of spur gears is assigned to form gear stages of the first transmission input shaft and the second transmission input shaft; a third pair of spur gears is assigned to the second transmission input shaft for forming gear stages; and the first transmission input shaft and the second transmission input shaft are arranged coaxially to each other.

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

[0011] Furthermore, the above problem is solved by a method for operating a motor vehicle powertrain as defined above.

[0012] The above problem is finally solved by a motor vehicle comprising: a motor vehicle powertrain as defined above; and an energy storage device for storing energy to supply the first electric drive motor, a second electric drive motor and / or a further electric motor.

[0013] Preferred embodiments of the invention are described in the dependent claims. It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the present invention. In particular, the motor vehicle powertrain, the motor vehicle, and the method can be implemented according to the embodiments described for the hybrid transmission in the dependent claims.

[0014] A compact hybrid transmission can be created with a simple technical approach: a first input shaft for connecting the hybrid transmission to an internal combustion engine and a second input shaft for connecting the hybrid transmission to a first electric drive motor. The connection can be either switchable or non-switchable. A planetary gear set, effectively connected to both the first input shaft and the output shaft, enables a compact hybrid transmission with a wide range of functions. In particular, a hybrid transmission can be designed that allows for charging-in-neutral, electrodynamic starting, and electrodynamic shifting. Furthermore, a hybrid transmission with a simple mechanical design and only three actuators can be achieved in a compact form factor.The hybrid transmission is preferably characterized by low component stress, low transmission losses, and high gear efficiency for both the combustion engine and the electric motor. Output-based shifting is possible within the transmission. In particular, a transition from the charging-to-neutral state to three gear stages for the combustion engine is possible, enabling efficient, rapid shifting and highly efficient operation with the hybrid transmission. By assigning the first spur gear pair to the first transmission input shaft, the second spur gear pair to both the first and second transmission input shafts, and the third spur gear pair to the second transmission input shaft, a highly compact hybrid transmission can be created. Preferably, the first and second transmission input shafts are mounted coaxially and can be connected.Assigning a pair of spur gears to a transmission shaft means in particular that the pair of spur gears can be effectively connected to the corresponding transmission shaft by inserting a switching element.

[0015] In an advantageous embodiment, a fixed gear or a loose gear of the third spur gear pair can be connected to a rotor shaft of the first electric drive motor by means of one or more meshing gears to form gear stages. Alternatively, the second transmission input shaft has a connecting gear, wherein the second transmission input shaft can be connected to the rotor shaft of the first electric drive motor via one or more meshing gears by means of the connecting gear. By connecting the first electric drive motor via the third spur gear pair, a weight-optimized hybrid transmission can be created, since no further components are required in the hybrid transmission for connecting the electric drive motor. Connecting the first electric drive motor via a connecting gear allows for a large degree of flexibility in the gear ratio of the first electric drive motor.Consequently, a wide range of input gear ratios can be covered when connecting the first electric drive motor. This makes it technically easy to use an electric drive motor optimized for the application of the hybrid transmission. In particular, the size or power of the first electric drive motor can be selected according to the gear ratio and the hybrid transmission.

[0016] In a further advantageous embodiment, the arrangement of the loose gear and the fixed gear can be interchanged in one of the spur gear pairs used to form the gear stages. This allows for the creation of a hybrid transmission that can be variably adapted to installation space requirements. In particular, the interchangeability allows for the optimized implementation of a switching element using an actuator.

[0017] In a further advantageous embodiment, the hybrid transmission has a transmission input shaft that is effectively connected to the first transmission input shaft and is arranged parallel to the first transmission input shaft. Additionally or alternatively, the output shaft is effectively connected to a differential of the output, wherein the differential comprises a differential shaft for transmitting drive power from the hybrid transmission to the wheels of the vehicle. This differential shaft is arranged parallel to the output shaft and is designed to penetrate the first electric drive motor, thus enabling the first electric drive motor to be arranged around the differential shaft. Preferably, the transmission input shaft is effectively connected to the first transmission input shaft by means of a chain or a gear chain.The advantageous arrangement described above allows for an axially parallel connection of the combustion engine to a transmission shaft of the hybrid transmission. It is understood that a damper or vibration damper element can also be arranged on the transmission input shaft. By penetrating the first electric drive motor, a highly efficient and space-saving mounting or arrangement of the first electric drive motor within the hybrid transmission or hybrid powertrain can be achieved. The compactness of the hybrid transmission can be further improved.

[0018] In one embodiment according to the invention, a planet carrier of the planetary gear set is effectively connected to the output shaft, wherein the sun gear of the planetary gear set is connected to the first transmission input shaft by means of the first spur gear pair of the spur gear pairs to form the gear stages, and the ring gear of the planetary gear set can be connected to the first transmission input shaft or the second transmission input shaft by means of the second spur gear pair of the spur gear pairs to form the gear stage. Alternatively, the planet carrier of the planetary gear set is effectively connected to the output shaft, wherein the ring gear of the planetary gear set is connected to the first transmission input shaft by means of the first spur gear pair of the spur gear pairs to form the gear stages, and the sun gear of the planetary gear set can be connected to the first transmission input shaft or the second transmission input shaft by means of the second spur gear pair of the spur gear pairs to form the gear stages.This advantageous connection of the planetary gear set allows an electrodynamic superposition state to be established with the planetary gear set by means of the first electric drive motor and the internal combustion engine. The two alternative connections according to the invention mentioned above allow the first electric drive motor to be operated either at a low balancing speed during electrodynamic starting or electrodynamic switching, or alternatively, to provide only a low supporting torque during electrodynamic starting and switching. Furthermore, the two alternative connections according to the invention allow the duration of generator operation during electrodynamic starting to be maintained for a longer or shorter period.

[0019] In a further advantageous embodiment, the hybrid transmission features an internal combustion engine clutch for the detachable, drive-effective connection of the first transmission input shaft to the internal combustion engine, the internal combustion engine clutch preferably being arranged on the transmission input shaft. It is understood that the internal combustion engine clutch can be designed as a dog clutch or a friction clutch. An internal combustion engine clutch allows the internal combustion engine to be decoupled from the hybrid transmission, thus enabling a highly efficient, purely electric driving mode via the hybrid transmission. A friction clutch also enables a so-called momentum start of the internal combustion engine and can serve as a starting element for the internal combustion engine. An internal combustion engine clutch increases the variability and efficiency of the hybrid transmission.Furthermore, for functional safety reasons, an internal combustion engine clutch can be used in a hybrid transmission.

[0020] In a further advantageous embodiment, a first switching element is configured to effectively connect the first transmission input shaft to the second transmission input shaft. Additionally or alternatively, a second switching element is configured to effectively connect the first transmission input shaft to the planetary gear set via the second spur gear pair. Furthermore, additionally or alternatively, a third switching element is configured to lock the planetary gear set. Additionally or alternatively, a fourth switching element is configured to effectively connect the second transmission input shaft to the output shaft via the third spur gear pair. Finally, additionally or alternatively, a fifth switching element is configured to effectively connect the second transmission input shaft to the planetary gear set via the second spur gear pair.This advantageous arrangement of the switching elements allows the hybrid transmission to offer four hybrid gear stages, some with multiple variants, a pure electric gear stage, an electrodynamic superposition state, and a charge-in-neutral mode. This enables the creation of a variable and compact hybrid transmission that allows for electrodynamic starting and shifting.

[0021] In a further advantageous embodiment, the hybrid transmission comprises exactly three spur gear pairs, exactly one planetary gear set, and exactly five switching elements for forming four hybrid gear stages. The use of exactly three spur gear pairs and one planetary gear set allows for a compact hybrid transmission with few gear engagements, enabling four hybrid gear stages (some with multiple variants), a pure electric gear stage, an electrodynamic superposition state, and a charging-to-neutral state. The use of five switching elements allows for an easy-to-control, compact hybrid transmission.

[0022] In a further advantageous embodiment, the switching elements are designed as positive-locking switching elements. Additionally or alternatively, at least two of the switching elements, preferably four, are designed as double switching elements and can be actuated by a double-acting actuator. Positive-locking switching elements enable a highly efficient and cost-effective hybrid transmission. The technical design and operation of the hybrid transmission can be further simplified by using a double switching element. In particular, a double switching element can be switched by means of a single actuator.

[0023] In a further advantageous embodiment, the vehicle powertrain preferably comprises an additional electric machine that is effectively connected to the first transmission input shaft. The first electric drive machine and / or preferably the additional electric machine can be controlled as a starter-generator for starting the internal combustion engine. Additionally or alternatively, the first electric drive machine and / or preferably the additional electric machine can be controlled as a charging generator for charging an energy storage device. The additional electric machine is preferably designed as a high-voltage starter-generator. This allows for the creation of an efficient vehicle powertrain. In particular, fuel consumption can be reduced.It is understood that an additional starter for the internal combustion engine can be dispensed with, since the first electric drive motor and / or preferably the second electric motor can tow the internal combustion engine.

[0024] In a further advantageous embodiment, an output of the hybrid transmission can be effectively connected to a first vehicle axle, wherein a second vehicle axle comprises an electric axle with a second electric drive motor. This allows for the simple creation of a hybrid powertrain with all-wheel drive. Furthermore, the vehicle powertrain enables seamless shifting without interruption of traction, as the electric axle can maintain traction during shifts in the hybrid transmission. In addition, a fail-safe powertrain for a vehicle can be created, since a so-called serial driving mode can be established if the energy storage for the second electric drive motor is depleted.In the series driving mode, the electric drive motor is preferably operated as a generator by the combustion engine, and the energy thus generated is supplied to the second electric drive motor. This allows for the creation of a highly variable vehicle powertrain, in which electric driving and, in particular, electric starting are possible even when the energy storage is empty.

[0025] A planetary gear set is locked together by connecting two gears and / or the planet carrier and a gear of the planetary gear set in a way that provides a driving force, so that they rotate together at the same speed around the same point, preferably the center of the planetary gear set. When two gears and / or a planet carrier and a gear of the planetary gear set are locked together, the planetary gear set preferably acts like a shaft; in particular, no gear ratio is achieved within the planetary gear set.

[0026] In this context, "drive-effectively connected" or "connected" refers specifically to a non-switchable connection between two components, intended for the permanent transmission of rotational speed, torque, and / or drive power. This connection can be direct or via a fixed gear ratio. The connection can be made, for example, via a fixed shaft, a gear, particularly a spur gear, and / or a drive element, particularly a traction drive.

[0027] In this context, the terms "connectable for drive purposes," "can be connected for drive purposes," or "is designed for drive-effective connection" are understood to refer specifically to a switchable connection between two components which, in a closed state, is intended for the temporary transmission of rotational speed, torque, and / or drive power. In an open state, the switchable connection preferably transmits essentially no rotational speed, torque, and / or drive power, at least temporarily.

[0028] Stationary charging or charging-in-neutral refers in particular to operating the electric drive motor as a generator, preferably when stationary with the combustion engine running, in order to charge an energy storage device and / or to power on-board electronics.

[0029] In this context, an actuator is in particular a component that converts an electrical signal into a mechanical movement. Preferably, actuators used with dual switching elements perform movements in two opposite directions, in order to switch one switching element of the dual switching element in the first direction and to switch the other switching element in the second direction.

[0030] A gear change, particularly a series shift, is achieved by disengaging a shift element and / or clutch and simultaneously engaging the shift element and / or clutch for the next higher or lower gear. The second shift element and / or clutch thus gradually takes over the torque from the first shift element and / or clutch until, at the end of the gear change, the entire torque is being handled by the second shift element and / or clutch. With prior synchronization, a gear change can be performed more quickly; preferably, positive-locking shift elements can be used for this purpose.

[0031] An internal combustion engine can be any machine that can generate rotary motion by burning a fuel such as gasoline, diesel, kerosene, ethanol, liquefied petroleum gas (LPG), or autogas. Examples of internal combustion engines include gasoline engines, diesel engines, Wankel engines, and two-stroke engines.

[0032] In serial driving or creep mode, an electric motor of a vehicle is driven as a generator by an internal combustion engine of the same vehicle. The energy generated in this way is then supplied to another electric motor of the vehicle to provide propulsion power.

[0033] An electric vehicle axle, or simply electric axle, is preferably a non-main drive axle of a motor vehicle, in which drive power can be transmitted to the wheels of the motor vehicle by means of an electric drive motor. It is understood that the electric drive motor can also be connected via a transmission. Traction can be maintained wholly or partially by means of an electric axle when a gear change occurs in the transmission for a main drive axle. Furthermore, an all-wheel-drive functionality can be implemented, at least partially, by means of an electric axle.

[0034] An electrodynamic starting element (EDA) uses one or more planetary gear sets to superimpose the speeds of the combustion engine and the electric drive motor, enabling a vehicle to start from a standstill with the combustion engine running, preferably without a friction clutch. The electric drive motor provides torque support. Preferably, the combustion engine can no longer be disconnected from the transmission by a starting clutch or similar device. Using an EDA preferably eliminates the need for a starter, generator, and starting clutch or hydrodynamic torque converter. In particular, an EDA is designed to be so compact that all components fit within the standard clutch housing without extending the transmission.The electrodynamic starting element can be rigidly connected to an internal combustion engine, and in particular to the flywheel of an internal combustion engine, via a softly tuned torsional damper. This allows the electric drive and the internal combustion engine to be operated either simultaneously or alternatively. When the vehicle comes to a stop, both the electric drive and the internal combustion engine can be switched off. Due to the precise controllability of the electric drive, a very high level of starting performance is achieved, comparable to that of a drive with a torque converter.

[0035] In a so-called electrodynamic shift (EDS), as with EDA starting, the speeds of the combustion engine and the electric drive motor are superimposed via one or more planetary gear sets. At the start of the shift, the torques of the electric drive motor and the combustion engine are adjusted so that the shift element to be engaged is unloaded. After this shift element opens, the speed is adjusted while maintaining the tractive force, so that the shift element to be engaged becomes synchronous. After the shift element closes, the load distribution between the combustion engine and the electric drive motor occurs as desired, depending on the hybrid operating strategy.The electrodynamic shifting method has the advantage that the shift element to be selected for the target gear is synchronized by the interaction of the electric drive motor and the combustion engine, with the electric drive motor preferably being precisely controllable. A further advantage of the EDS shifting method is that high tractive force can be achieved, since the torques of the combustion engine and the electric motor combine in the hybrid transmission.

[0036] The invention is described and explained in more detail below with reference to some selected embodiments in conjunction with the accompanying drawings. These show: Fig. 1 a schematic top view of a motor vehicle with a motor vehicle drive train according to the invention; Fig. 2 a schematic representation of a variant of a hybrid transmission according to the invention; Fig. 3. Schematic representation of the switching states of the hybrid transmission according to the Fig. 2; Fig. 4 a schematic representation of another variant of a hybrid transmission; Fig. 5 a schematic representation of another variant of a hybrid transmission; Fig. 6 a schematic representation of another variant of a hybrid transmission; Fig. 7 a schematic representation of another variant of a hybrid transmission; Fig. 8 a schematic representation of another variant of a hybrid transmission; Fig. 9 a schematic representation of another variant of a hybrid transmission; and Fig. 10 a schematic representation of another variant of a hybrid transmission.

[0037] In Fig. Figure 1 schematically shows a motor vehicle 10 with a motor vehicle powertrain 12. The motor vehicle powertrain 12 comprises a first electric drive motor 14 and an internal combustion engine 16, which are connected to a front axle of the motor vehicle 10 by means of a hybrid transmission 18. In the example shown, the motor vehicle powertrain 12 also includes an optional electric axle with a second electric drive motor 20, which is connected to a rear axle of the motor vehicle 10. It is understood that a reverse connection is also possible, such 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.The motor vehicle powertrain 12 supplies drive power to the wheels of the motor vehicle 10 from the first electric drive motor 14, the internal combustion engine 16 and / or the optional second electric drive motor 20. The motor vehicle 10 also has an energy storage device 22 to store energy that is used to supply the first electric drive motor 14 and / or the second electric drive motor 20.

[0038] Fig. Figure 2 shows a simplified version of a hybrid transmission 18 according to the invention. The hybrid transmission 18 has a first transmission input shaft 24 and a second transmission input shaft 26, which are designed to transmit drive power from the drive machines 14, 16 into the hybrid transmission 18.

[0039] Furthermore, the hybrid transmission 18 includes an output shaft 28 as well as a planetary gear set RS and three spur gear pairs, which are designated ST1 to ST3.

[0040] The first spur gear pair ST1 comprises a fixed gear arranged on the first transmission input shaft 24 and a fixed gear arranged on a hollow shaft (not otherwise specified), the hollow shaft being effectively connected to a ring gear of the planetary gear set RS. This hollow shaft is arranged on the output shaft 28 and surrounds it at least partially.

[0041] The second spur gear pair ST2 has a loose gear which is arranged on the second transmission input shaft 26 and engages with a fixed gear arranged on a further hollow shaft, wherein the further hollow shaft is effectively connected to a sun gear of the planetary gear set RS and surrounds the output shaft 28 at least partially.

[0042] The third spur gear pair ST3 has a fixed gear arranged on the second transmission input shaft 26, which meshes with a loose gear arranged on the output shaft 28. Furthermore, the fixed gear of the third spur gear pair ST3 is effectively connected to an output shaft or rotor shaft of the first electric drive machine 14 by means of two gears.

[0043] The hybrid transmission 18 further comprises five switching elements A - E, which are preferably designed as positive-locking switching elements, for example claw switching elements.

[0044] By inserting the first switching element A, the first transmission input shaft 24 can be effectively connected to the second transmission input shaft 26.

[0045] The second switching element B is designed to connect the first transmission input shaft 24 to the loose gear of the second spur gear pair ST2 in a drive-effective manner, whereby no drive-effective connection to the second transmission input shaft 26 is established in this connection.

[0046] The third switching element C is designed to effectively connect a planet carrier of the planetary gear set RS, which is connected to the output shaft 28, to a sun gear of the planetary gear set RS. In other words, the third switching element C is designed to lock the planetary gear set RS.

[0047] A fourth switching element D is configured to effectively connect the loose gear of the third spur gear pair ST3 to the output shaft 28. A fifth switching element E is configured to effectively connect the loose gear of the second spur gear pair ST2 to the second transmission input shaft 26.

[0048] The first switching element A is combined with the second switching element B to form a double switching element.

[0049] The third switching element C is combined with the fourth switching element D to form a double switching element.

[0050] According to the hybrid transmission 18 Fig. The gear set shown in Figure 2 can be followed by a fixed gear ratio in the form of another planetary gear set or a spur gear stage. It is also understood that a differential is usually connected downstream of the disclosed gear set.

[0051] The first transmission input shaft 24 is axially offset and arranged coaxially to the second transmission input shaft 26.

[0052] The output shaft is arranged parallel to the axis of the first transmission input shaft 24 and the second transmission input shaft 26.

[0053] In Fig. Figure 32 of a switching matrix shows, in the first column, the hybrid gear stages H1–H4, some with multiple variants, an electric gear stage E1, an electrodynamic superposition state EDA, and a charging-in-neutral state LiN. Columns two through six show the switching states of the switching elements A–E, where an "X" indicates that the respective switching element is closed, thus effectively connecting the associated transmission components. If no entry is present, it can be assumed that the corresponding switching element is open, i.e., transmitting no drive power.

[0054] A first variant of the first hybrid gear stage H1.1 can be set up by closing the third switching element C and the fifth switching element E.

[0055] Closing the first switching element A and the third switching element C establishes a second variant of the first hybrid gear stage H1.2.

[0056] The second hybrid gear stage H2 can be set up by closing the fourth switching element D and the fifth switching element E.

[0057] A first variant of the third hybrid gear stage H3.1 can be set up by closing the first switching element A and the fifth switching element E.

[0058] A second variant of the third hybrid gear stage H3.2 can be set up by closing the second switching element B and the fourth switching element D.

[0059] Closing the second switching element B and the fifth switching element E establishes a third variant of the third hybrid gear stage H3.3.

[0060] The fourth hybrid gear stage H4 can be set up by inserting the first switching element A and the fourth switching element D.

[0061] The electric stage E1 can be set up by closing the fourth switching element D.

[0062] Closing the fifth switching element E establishes an electrodynamic superposition state EDA.

[0063] The state "Load-in-Neutral LiN" can be set by closing the first switching element A.

[0064] For combustion engine or hybrid driving, several different hybrid gear ratios are available for the combustion engine 16.

[0065] If only the fourth switching element D is closed, purely electric operation is possible, since the electric drive motor 14 is directly connected to the output 30.

[0066] If only the fifth switching element E is closed, an EDA state, i.e., an electrodynamic superposition state, is created at the planetary gear set RS. This state can be used in particular for electrodynamic starting or for electrodynamic load shifting. The internal combustion engine 16 is then connected to the ring gear of the planetary gear set RS via the first spur gear pair ST1, with the first electric drive motor 14 supporting the torque of the internal combustion engine 16 via the second spur gear pair ST2 on the sun gear of the planetary gear set. The planet carrier of the planetary gear set RS is connected to the output 30 via the output shaft 28. In this state, EDA, i.e., electrodynamic starting, is possible in forward motion. From this switching state, the first variant of the first hybrid gear stage H1.1, the second hybrid gear stage H2, and the first variant of the third hybrid gear stage H3 can be selected for the internal combustion engine 16.1 or the third variant of the third hybrid gear stage H3.3 can be engaged, because the fifth switching element E is closed in these switching states.

[0067] A shift from second to third gear can be performed with output assistance from the first electric drive motor 14, with the fourth switching element D remaining closed. The transmission then shifts from the second hybrid gear stage H2 to the second variant of the third hybrid gear stage H3.2. A shift from third to fourth gear can also be performed with output assistance from the first electric drive motor 14, with the fourth switching element D remaining closed. The transmission then shifts from the second variant of the third hybrid gear stage H3.2 to the fourth hybrid gear stage H4.

[0068] An electrodynamic or electromechanical load switching operation from the second hybrid gear stage H2 to the second variant of the third hybrid gear stage H3.2 in hybrid operation can be carried out, for example, as follows. Initially, the second hybrid gear stage H2 is engaged. The fourth switching element D and the fifth switching element E are closed. Then, the load is reduced at the fifth switching element E and simultaneously increased at the first electric drive motor 14. The fifth switching element E is then opened. Subsequently, the speed of the combustion engine 16 is reduced so that the second switching element B becomes synchronized. For this purpose, the combustion engine 16 can, for example, operate another electric motor as a generator, which is preferred, or the combustion engine 16 can enter overrun mode. The second switching element B can then be engaged. During this switching operation, the fourth switching element D remains closed.

[0069] If only the first switching element A is closed, the first electric drive motor 14 can be connected to the combustion engine 16 independently of the output 30. The first electric drive motor 14 and the combustion engine 16 then rotate at a fixed ratio to each other. In this state, it is possible, on the one hand, to start the combustion engine 16 using the first electric drive motor 14. On the other hand, the first electric drive motor 14 can be operated by the combustion engine 16 as a generator and charge the electrical energy storage device 22 or supply electrical consumers. A consumer can also be the second electric drive motor 20, as for example in Fig. Figure 1 shows the electric motor located on the other vehicle axle, which drives it. The second electric drive motor 20 thus forms an electric rear axle. A transition from the charging-to-neutral state LiN to the second variant of the first hybrid gear stage H1.2, the first variant of the third hybrid gear stage H3.1, and the fourth hybrid gear stage H4 is possible because the first switching element A is closed in each of these switching states.

[0070] Is a second electric drive motor 20 present in the drive train 12, as for example in Fig. As shown in Figure 1, this combination can create an all-wheel drive system. For example, a DHT (Dedicated Hybrid Transmission) with the combustion engine 16 and the first electric drive motor 14 can be designed as a pure front-wheel drive, with an additional rear-axle drive provided by the separate second electric drive motor 20. In this configuration, the electrodynamic superposition state is a power-split E-CVT driving range for the combustion engine 16, in which battery-neutral operation is also possible. The CVT driving range refers specifically to a continuously variable transmission (CVT) driving range, where the E denotes the support provided by the first electric drive motor 14 and / or the second electric drive motor 20.

[0071] Traction assistance can be provided by means of the second electric drive motor 20. For example, the second electric drive motor 20 can support the traction force at the rear axle when switching operations are necessary in the hybrid transmission 18, during which the output 30 of the hybrid transmission 18 becomes unloaded. An example of such a transition is when the vehicle is initially driven purely electrically using the first electric drive motor 14 and / or the second electric drive motor 20, and then the combustion engine 16 is to be started in neutral using the first electric drive motor 14.

[0072] In Fig. Figure 4 shows another variant of a hybrid transmission 18 according to the invention. In contrast to the one in Fig. In the embodiment shown in Figure 2, the first electric drive motor 14 is connected to the loose gear of the third spur gear pair ST3. The remaining transmission components and connections are identical to those shown in Figure 2. Fig. 2 embodiment shown.

[0073] In Fig. Figure 5 shows another variant of a hybrid transmission 18 according to the invention. In contrast to the one in Fig. In the embodiment shown in Figure 2, the second transmission input shaft 26 comprises a connecting gear, which is designed as a fixed gear and is effectively connected to a rotor shaft of the first electric drive motor 14 by means of a gear chain. In contrast to the embodiments shown previously, the connection of the first electric drive motor 14 is effected here via a separate connecting gear.

[0074] In Fig. Figure 6 shows another variant of a hybrid transmission 18 according to the invention. In contrast to the one in Fig. In the embodiment shown in Figure 5, the fixed and loose gear connections of the third spur gear pair ST3 are reversed. The loose gear of the third spur gear pair ST3 is arranged on the second transmission input shaft 26. It is understood that the fourth shifting element D is also arranged on the second transmission input shaft 26. The fixed gear of the third spur gear pair ST3 is arranged on the output shaft 28. Furthermore, the hybrid transmission has only one double shifting element comprising the first shifting element A and the second shifting element B. The remaining shifting elements C - E are designed as single shifting elements. In contrast to the previous embodiments, the double shifting element comprising the third shifting element C and the fourth shifting element D is therefore omitted.

[0075] In Fig. Figure 7 shows another variant of a hybrid transmission 18 according to the invention. In contrast to the one in Fig. In the embodiment shown in Figure 2, the connections to the planetary gear set RS are modified. In particular, the connections to the ring gear and sun gear of the planetary gear set RS are swapped. The output 30 or the output shaft 28 remains connected to the planet carrier of the planetary gear set RS. In the embodiment shown in Fig. In the embodiment shown in Figure 7, the first electric drive motor 14 is connected to the ring gear of the planetary gear set RS via the second spur gear pair ST2 and the closed fifth switching element E, with the internal combustion engine 16 being effectively connected to the sun gear of the planetary gear set RS via the first spur gear stage ST1. This configuration allows the first electric drive motor 14 to be operated at a lower balancing speed during electrodynamic starting (EDA) or electrodynamic switching (EDS). For this purpose, the first electric drive motor 14 requires a high supporting torque during electrodynamic starting and switching.Furthermore, during electrodynamic starting, the first electric drive machine 14 can be operated as a generator for a shorter time than if the first electric drive machine 14 were connected to the sun gear of the planetary gear set RS, since the generator operation is ended earlier with increasing driving speed.

[0076] In Fig. Figure 8 shows another variant of a hybrid transmission 18 according to the invention. The hybrid transmission 18 according to the Fig. 8 essentially corresponds to the one in Fig. 4 hybrid transmissions shown 18, wherein in Fig. Figure 8 shows the output 30 in more detail. The output 30 is formed by an output gear arranged between the planetary gear set RS and the second spur gear pair ST2 on the output shaft 28, the output shaft 28 having a hollow shaft section 28a on which the output gear is arranged. The hollow shaft section 28a is connected to the output shaft 28, which is otherwise designed as a solid shaft, via the planet carrier of the planetary gear set RS and surrounds the output shaft 28 at least partially. The output gear is in mesh with a fixed gear arranged on a differential and thus transmits drive power from the hybrid transmission 18 to the differential. The differential also has a differential shaft 38 that penetrates a rotor shaft of the first electric drive motor 14. In other words, the first electric drive motor 14 can be mounted on the differential shaft 38.

[0077] Furthermore, the hybrid transmission 18 has a transmission drive shaft 34, which is arranged parallel to the axis of the first transmission input shaft 24 and is connected to the first transmission input shaft 24 via a traction gear with a fixed gear arranged between the first spur gear pair ST1 and the second spur gear pair ST2.

[0078] In the embodiment shown, the first transmission input shaft 24 is designed as a hollow shaft and surrounds the second transmission input shaft 26, which is designed as a solid shaft, at least partially.

[0079] The transmission drive shaft 34 is connected to the internal combustion engine 16 via a torsional vibration damper or another element known in principle in the prior art for torsional vibration decoupling. Furthermore, a fixed gear for connecting a further electric machine 36 is arranged on the transmission drive shaft 34. The further electric machine 36 is operatively connected to the transmission drive shaft 34 via a traction drive. Particularly preferably, the further electric machine 36 can be designed as a high-voltage starter generator.

[0080] It is understood that the connection of the transmission drive shaft 34 to both the first transmission input shaft 24 and the further electric machine 36 can alternatively also be designed as a gear chain.

[0081] In Fig. Figure 9 shows another variant of a hybrid transmission 18 according to the invention. In contrast to the one in Fig. In the embodiment shown in Figure 8, the transmission drive shaft 34 comprises an internal combustion engine coupling K0. The internal combustion engine coupling K0 is designed to connect the transmission drive shaft 34 to the internal combustion engine 16 in a separably drive-effective manner. The internal combustion engine coupling K0 arranged between the element for torsional vibration decoupling and the two connecting gears of the transmission drive shaft 34, so that the further electric machine 36 is always in drive connection with the first transmission input shaft 24.

[0082] In the Fig. In the example shown in 9, the combustion engine coupling K0 is designed as a positive-locking switching element, for example as a claw coupling.

[0083] In Fig. Figure 10 shows another variant of a hybrid transmission 18 according to the invention. In contrast to the one in Fig. In the embodiment shown in Figure 9, the combustion engine coupling K0 is designed as a friction-fit switching element.

[0084] It is understood that the motor vehicle powertrain 12 or the hybrid transmission 18 can also be operated without an internal combustion engine clutch K0. Nevertheless, an internal combustion engine clutch K0 can be advantageous for various reasons, such as functional safety considerations. In particular, an internal combustion engine clutch K0 in the form of a friction-fit switching element, as in Fig. Figure 10 shows a towing start of the combustion engine 16. In particular, in an embodiment with a further electric machine 36, a combustion engine coupling K0 is useful.

[0085] The invention has been comprehensively described and explained with reference to the drawings and the description. The description and explanation are to be understood as examples and not as limiting. The invention is not limited to the disclosed embodiments. Other embodiments or variations will become apparent to a person skilled in the art when using the present invention and upon a detailed analysis of the drawings, the disclosure, and the subsequent claims.

[0086] In the claims, the words "comprise" and "with" do not preclude the presence of further elements or steps. The undefined article "a" or "an" does not preclude the presence of multiple elements. A single element or unit can perform the functions of several of the units mentioned in the claims. The mere mention of some measures in several different dependent claims is not to be understood as precluding the advantageous use of a combination of these measures. Reference numerals in the claims are not to be understood restrictively. For example, a method for operating a motor vehicle powertrain 12 can be implemented in the form of a computer program executed on a control unit for the motor vehicle powertrain 12.A computer program can be stored / distributed on a non-volatile storage medium, such as an optical memory or a solid-state drive (SSD). A computer program can be distributed together with hardware and / or as part of hardware, for example, via the internet or via wired or wireless communication systems. Reference sign 10 motor vehicle 12 Automotive Powertrain 14 first electric drive motor 16 Internal combustion engine 18 hybrid transmissions 20 second electric drive motor 22 Energy storage 24 first gearbox input shaft 26 second gearbox input shaft 28 Output shaft 28a Hollow shaft section 30 downforce 32 switching matrix 34 Gearbox drive shaft 36 more electric machines 38 Differential shaft A to E Switching elements K0 combustion engine clutch ST1 to ST3 spur gear pairs

Claims

Hybrid transmission (18) for a motor vehicle powertrain (12) of a motor vehicle (10), comprising: a first transmission input shaft (24) for operatively connecting the hybrid transmission (18) to an internal combustion engine (16) of the motor vehicle (10); a second transmission input shaft (26) for operatively connecting the hybrid transmission (18) to a first electric drive motor (14) of the motor vehicle (10); an output shaft (28) for operatively connecting the hybrid transmission (18) to an output (30); a planetary gear set (RS) which is non-switchably connected to the first transmission input shaft (24) and the output shaft (28); spur gear pairs (ST1, ST2, ST3) arranged in several gear set planes for forming gear stages; and several gearshift devices with shift elements (A, B, C, D, E) for engaging gear stages, wherein a first spur gear pair (ST1) of the spur gear pairs (ST1, ST2, ST3) is assigned to the first transmission input shaft (24) for forming gear stages;a second spur gear pair (ST2) of the spur gear pairs (ST1, ST2, ST3) is assigned to form gear stages of the first transmission input shaft (24) and the second transmission input shaft (26); a third spur gear pair (ST3) of the spur gear pairs (ST1, ST2, ST3) is assigned to form gear stages of the second transmission input shaft (26); and the first transmission input shaft (24) and the second transmission input shaft (26) are arranged coaxially to each other, wherein a planet carrier of the planet gear set (RS) is effectively connected to the output shaft (28);the sun gear of the planetary gear set (RS) is connected to the first transmission input shaft (24) by means of the first spur gear pair (ST1) of the spur gear pairs (ST1, ST2, ST3) to form the gear stages and the ring gear of the planetary gear set (RS) can be connected to the first transmission input shaft (24) or the second transmission input shaft (26) by means of the second spur gear pair (ST2) of the spur gear pairs (ST1, ST2, ST3) to form the gear stages; or the ring gear of the planetary gear set (RS) is connected to the first transmission input shaft (24) by means of the first spur gear pair (ST1) of the spur gear pairs (ST1, ST2, ST3) to form the gear stages, and the sun gear of the planetary gear set (RS) can be connected to the first transmission input shaft (24) or the second transmission input shaft (26) by means of the second spur gear pair (ST2) of the spur gear pairs (ST1, ST2, ST3) to form the gear stages. Hybrid transmission (18) according to claim 1, wherein a fixed gear or a loose gear of the third spur gear pair (ST3) of the spur gear pairs (ST1, ST2, ST3) can be connected to a rotor shaft of the first electric drive machine (14) for forming gear stages by means of one or more meshing gears; the second transmission input shaft (26) has a connecting gear, wherein the second transmission input shaft (26) can be connected to the rotor shaft of the first electric drive machine (14) by means of the connecting gear via one or more meshing gears. Hybrid transmission (18) according to claim 1 or 2, wherein in one of the spur gear pairs (ST1, ST2, ST3) for forming the gear stages an arrangement of the loose gear with the arrangement of the fixed gear is interchangeable. Hybrid transmission (18) according to one of the preceding claims, wherein the hybrid transmission (18) has a transmission input shaft (34) which is effectively connected to the first transmission input shaft (24) and is arranged parallel to the axis of the first transmission input shaft (24), and / or the output shaft (28) is effectively connected to a differential of the output (30), wherein the differential comprises a differential shaft (38) for transmitting drive power from the hybrid transmission (18) to the wheels of the motor vehicle (10), which is arranged parallel to the axis of the output shaft (28) and is designed to penetrate the first electric drive motor (14) in order to enable the first electric drive motor (14) to be arranged around the differential shaft. Hybrid transmission (18) according to one of the preceding claims, with an internal combustion engine coupling (K0) for releasably connecting the first transmission input shaft (24) to the internal combustion engine (16) in a drive-effective manner. Hybrid transmission (18) according to one of the preceding claims, wherein a first switching element (A) is configured to effectively connect the first transmission input shaft (24) to the second transmission input shaft (26) for driving purposes; a second switching element (B) is configured to effectively connect the first transmission input shaft (24) to the planetary gear set (RS) by means of the second spur gear pair (ST2); a third switching element (C) is configured to lock the planetary gear set (RS); a fourth switching element (D) is configured to effectively connect the second transmission input shaft (26) to the output shaft (28) by means of the third spur gear pair (ST3); and / or a fifth switching element (E) is configured to effectively connect the second transmission input shaft (26) to the planetary gear set (RS) by means of the second spur gear pair (ST2) for driving purposes. Hybrid transmission (18) according to one of the preceding claims, wherein the hybrid transmission (18) comprises exactly three spur gear pairs (ST1, ST2, ST3), exactly one planetary gear set (RS) and exactly five switching elements (A, B, C, D, E) for forming four hybrid gear stages. Hybrid transmission (18) according to one of the preceding claims, wherein the output shaft (28) is designed as a solid shaft at least partially; and / or wherein the first transmission input shaft (24) is designed as a hollow shaft and surrounds the second transmission input shaft (26) designed as a solid shaft at least partially. Hybrid transmission (18) according to one of the preceding claims, wherein the switching elements (A, B, C, D, E) are designed as positive-locking switching elements; and / or at least two of the switching elements (A, B, C, D, E) are designed as double switching elements and can be actuated by a double-acting actuator. Motor vehicle powertrain (12) for a motor vehicle (10), comprising: a hybrid transmission (18) according to one of the preceding claims; an internal combustion engine (16) which can be connected to the first transmission input shaft (24); and a first electric drive motor (14) which is effectively connected to the second transmission input shaft (26). Motor vehicle powertrain (12) according to claim 10, wherein the first electric drive machine (14) can be controlled as a starter generator for starting the internal combustion engine (16); and / or can be controlled as a charging generator for charging an energy storage device (22). Motor vehicle powertrain (12) according to claim 10 or 11, wherein the output (30) of the hybrid transmission (18) can be connected to a first motor vehicle axle in a drive-effective manner and a second motor vehicle axle comprises an electric axle with a second electric drive motor (20). Method for operating a motor vehicle powertrain (12) according to one of claims 10 to 12 . Motor vehicle (10) comprising: a motor vehicle powertrain (12) according to one of claims 10 to 12; and an energy storage device (22) for storing energy to supply the first electric drive motor (14); a second electric drive motor (20) and / or a further electric motor (36).

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