Low-drag hybrid transmission in mixed construction

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 (32); exactly one planetary gear set (RS) connected to the first transmission input shaft (24) and the second transmission input shaft (26); exactly three pairs of spur gears (ST1, ST2, ST3) arranged in several gear set planes for forming gear stages; and several gear-shifting devices with exactly five shifting elements (A, B, C, D, E) for engaging gear stages, wherein the output shaft (28) is designed in a reduction gear design; and the planetary gear set (RS) can be decoupled and locked from the output shaft (28), and wherein the hybrid transmission has a transmission input shaft (36) which is effectively connected to the first transmission input shaft (24) and is arranged axially parallel to the first transmission input shaft (24), and / or the output shaft (28) is operatively connected to a differential of the output (32) in a drive-effective manner, wherein the differential comprises a differential shaft for transmitting drive power from the hybrid transmission (18) to wheels of the motor vehicle (10), which is arranged parallel to the axis of the output shaft (28) and is designed to support the first electric drive motor (14).

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 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, 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, 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] DE 10 2020 202 652 A1 discloses a motor vehicle with a first axle as an electric axle and a second axle to which a hybrid transmission arrangement is assigned. The hybrid transmission arrangement comprises a transmission assembly and at least one electric motor and is connected to an internal combustion engine. The transmission assembly is designed as a gear-shift transmission and comprises at least one planetary gear set and at least one spur gear set. The spur gear set, in turn, has two transmission input shafts, of which the first transmission input shaft is connected directly to the internal combustion engine without the interposition of the planetary gear set, and the second transmission input shaft is connected via the interposition of the planetary gear set.

[0008] German patent application DE 10 2021 202 256 A1 discloses a hybrid transmission arrangement for a vehicle, comprising a transmission arrangement and at least one electric motor. The transmission arrangement is designed as a gear-shifting transmission and includes at least one planetary gear set and at least one spur gear set. The spur gear set has a first transmission input shaft and a second transmission input shaft, wherein the first transmission input shaft is directly connected to an input side of the hybrid transmission arrangement without the planetary gear set being interposed, and the second transmission input shaft is connected via the planetary gear set. The planetary gear set comprises a positive planetary gear set with a sun gear, a ring gear, a planet carrier, at least one first planet gear, and at least one second planet gear, wherein each first and second planet gear is rotatably mounted on the common planet carrier.Each first planet gear meshes with the sun gear and the respective second planet gear, and each second planet gear also meshes with the ring gear.

[0009] Furthermore, DE 10 2020 216 298 A1 discloses a transmission for a motor vehicle, comprising an electric motor, a first input shaft, a second input shaft, and a countershaft. The countershaft is permanently connected to an output side. A first spur gear stage is provided, comprising a fixed gear located on the first input shaft and a meshing loose gear. This fixed gear is rotatably mounted on the countershaft and can be locked to the countershaft by means of a first switching element. A second spur gear stage is also provided, comprising a fixed gear located on the second input shaft and a meshing loose gear. This loose gear is rotatably mounted on the countershaft and can be locked to the countershaft by means of a second switching element. The loose gear of the first spur gear stage and the loose gear of the second spur gear stage can be connected to each other in a rotationally fixed manner by means of a third switching element.A planetary gear stage comprises a first element, a second element, and a third element in the form of a sun gear, a planetary carrier, and a ring gear, respectively. The second element is rotationally fixed to the second input shaft, and the third element is coupled to a rotor of the electric machine. The first element of the planetary gear stage can be locked in place by actuating a fourth switching element, and two of the planetary gear stage elements can be rotationally fixed together by closing a fifth switching element.

[0010] Other hybrid transmissions of this type are known from DE 10 2016 225 236 A1, DE 10 2021 206 263 A1 and DE 10 2013 221 461 A1.

[0011] 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 enables charging-in-neutral, electrodynamic starting (EDA), and electrodynamic shifting (EDS).

[0012] The above problem is solved by a hybrid transmission for a motor vehicle powertrain, comprising: a first transmission input shaft for connecting the hybrid transmission to an internal combustion engine of the motor vehicle; a second transmission input shaft for connecting the hybrid transmission to a first electric drive motor of the motor vehicle; an output shaft for connecting the hybrid transmission to an output; exactly one planetary gear set connected to the first transmission input shaft and the second transmission input shaft; exactly three pairs of spur gears arranged in several gear set planes to form gear stages; and several gearshift devices with exactly five shift elements for engaging gear stages, wherein the output shaft is designed in a reduction gear design; and the planetary gear set can be decoupled and locked from the output shaft, and wherein the hybrid transmission has a transmission input shaft which is effectively connected to the first transmission input shaft and is arranged parallel to the axis of the first transmission input shaft, and / or 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 wheels of the motor vehicle, which is arranged parallel to the axis of the output shaft and is designed to support the first electric drive motor.

[0013] 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 which is effectively connected to the second gearbox input shaft.

[0014] The above problem is also solved by a method for operating a motor vehicle powertrain as defined above.

[0015] The above task is ultimately 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 and / or a second electric drive motor.

[0016] 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.

[0017] A compact hybrid transmission can be easily created by using a first input shaft to connect the hybrid transmission to an internal combustion engine and a second input shaft to connect the hybrid transmission to a first electric drive motor. The connection can be either switchable or non-switchable. A compact hybrid transmission can also be created by using an output shaft, designed as a countershaft, to connect the hybrid transmission to an output. In particular, the output shaft can be considered a countershaft. Consequently, a hybrid transmission can be created in which the countershaft also functions as an output shaft and is arranged parallel to the first and second input shafts.A compact hybrid transmission with a wide range of functions can be created using a planetary gear set connected to the first and second transmission input shafts. Specifically, this hybrid transmission enables charging-in-neutral, electrodynamic starting, and electrodynamic shifting. Because the planetary gear set can be decoupled and locked from the output shaft, a highly efficient pure electric gear stage can be implemented. In particular, a hybrid transmission with a simple design and only three actuators can be created in a compact form. The hybrid transmission exhibits low component stress, low transmission losses, and good gear efficiency in both combustion engine and electric modes. Output-driven shifting is also possible with this transmission.In particular, the first electric drive motor can be disengaged in two of the gear ranges, enabling highly efficient, purely combustion-engine operation. A transition from charging to neutral or from electrodynamic starting to any of the three mechanical gear ranges for the combustion engine is possible.

[0018] In an advantageous embodiment, the first transmission input shaft can be effectively connected to the output shaft via a first spur gear pair and a second spur gear pair to form the gear stages. This allows for the provision of at least two highly efficient, purely internal combustion engine gear stages. Additionally or alternatively, the planetary gear set and / or the second transmission input shaft can be connected to the output shaft via a third spur gear pair to form the gear stages. This allows for the technically simple establishment of an electrodynamic superposition state, particularly by engaging a single switching element. Furthermore, an electric gear stage can be established by engaging a single switching element, as can the charging-to-neutral state.

[0019] In a further advantageous embodiment, the second transmission input shaft is designed as a hollow shaft and surrounds the first transmission input shaft, at least partially. This further improves the compactness of the hybrid transmission. In particular, it is advantageous to mount the second transmission input shaft on the first transmission input shaft. Furthermore, a hollow second transmission input shaft allows the first electric drive motor to be connected to an outer surface of the hybrid transmission. This frees up installation space for a correspondingly large first electric drive motor.

[0020] According to the invention, the hybrid transmission has a transmission input shaft that is effectively connected to the first transmission input shaft and is arranged parallel to the axis of 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, the differential shaft being arranged parallel to the axis of the output shaft and designed to support the first electric drive motor. 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 axis-parallel connection of the combustion engine to a transmission shaft of the hybrid transmission.It is understood that a damper or vibration absorber can also be arranged on the transmission input shaft. Mounting the first electric drive motor on a transmission shaft allows for highly efficient and space-saving mounting and arrangement of the first electric drive motor within the hybrid transmission. This further improves the compactness of the hybrid transmission.

[0021] In a further advantageous embodiment, the planet carrier of the planetary gear set can be effectively connected to the output shaft. Additionally, the sun gear of the planetary gear set is effectively connected to the second transmission input shaft, and the ring gear of the first planetary gear set is effectively connected to the first transmission input shaft. Alternatively, the planet carrier of the planetary gear set can be effectively connected to the output shaft, and the ring gear of the first planetary gear set is effectively connected to the second transmission input shaft, and the sun gear of the planetary gear set is effectively connected to the first transmission input shaft.The two alternative connections mentioned above allow the first electric drive motor to either operate at a low balancing speed during electrodynamic starting or electrodynamic switching, or to provide only a low supporting torque during electrodynamic starting and switching. Furthermore, the duration of generator operation during electrodynamic starting can vary depending on the connection type.

[0022] 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, wherein the internal combustion engine clutch is preferably arranged on the transmission input shaft. It is understood that the internal combustion engine clutch can be designed as a dog 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 all-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.

[0023] According to the invention, the hybrid transmission comprises exactly three pairs of spur gears, exactly one planetary gear set, and exactly five switching elements for forming the gear stages. By using exactly three pairs of spur gears and one planetary gear set, a compact hybrid transmission with few gear engagements can be created, enabling three hybrid gear stages with multiple variants, a pure electric gear stage, an electrodynamic superposition state, and a charging-to-neutral state. The use of exactly five switching elements allows the output shaft to be designed without switching elements. Furthermore, a compact hybrid transmission that is easy to control can be created.

[0024] In a further advantageous embodiment, a first switching element is configured to effectively connect the first transmission input shaft to the output shaft by means of a first pair of spur gears. Additionally or alternatively, a second switching element is configured to effectively connect the first transmission input shaft to the output shaft by means of a second pair of spur gears. Furthermore, additionally or alternatively, a third switching element is configured to effectively connect the planetary gear set to the output shaft by means of a third pair of spur gears. Additionally or alternatively, a fourth switching element is configured to effectively connect the second transmission input shaft to the output shaft by means of a third pair of spur gears.Additionally or alternatively, a fifth switching element is designed to lock the planetary gear set, in particular to effectively connect the first transmission input shaft to the second transmission input shaft. This advantageous arrangement of the switching elements allows the hybrid transmission to provide three hybrid gear stages with multiple variants, as well as a purely electric gear stage. A variable and compact hybrid transmission can be created, enabling electrodynamic starting and electrodynamic shifting.

[0025] In a further advantageous embodiment, at least two of the spur gear pairs for forming the gear stages are interchangeable with respect to their axial position. Additionally or alternatively, in at least two spur gear pairs for forming the gear stages, the arrangement of the respective loose gear is interchangeable with the arrangement of the respective fixed gear. Finally, additionally or alternatively, the output shaft is designed without shift elements. By interchangeable spur gear pairs with respect to their axial position and by swapping the loose gear with the fixed gear of a respective spur gear pair, a variable hybrid transmission can be created that can be adapted, in particular, to given installation space requirements with ease. In particular, the interchangeability of the loose and fixed gears, and thus also the swapping of a shift element from, for example, an input shaft to the output shaft and / or vice versa, allows for advantageous access to the shift elements.

[0026] 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.

[0027] 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.

[0028] 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 gear changes 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 powered by the combustion engine in a generator-like manner, 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.

[0029] Locking an element of a planetary gear set is understood in particular as blocking the element's rotation about its axis of rotation. Preferably, the element is connected to a static component, such as a frame and / or a gearbox housing, in a rotationally fixed manner by means of a locking element. It is also conceivable to brake the element until it comes to a standstill.

[0030] 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.

[0031] In this context, "drive-effective connection" refers specifically to a non-switchable connection between two components, designed for the permanent transmission of rotational speed, torque, and / or drive power. This connection can be direct or via a fixed gear ratio. Examples of such connections include a fixed shaft, a gear, particularly a spur gear, and / or a drive element, especially a traction drive.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] 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.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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 schematically the switching states of the hybrid transmissions according to the Fig. 2; Fig. 4a, Fig. 4b Schematic representations of further variants 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; and Fig. 9 a schematic representation of another variant of a hybrid transmission.

[0042] 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.

[0043] 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.

[0044] The hybrid transmission 18 further comprises an output shaft 28 and a planetary gear set RS. A total of three spur gear pairs, designated ST1 to ST3, are arranged in the hybrid transmission 18.

[0045] The hybrid transmission has five switching elements A, B, C, D, E.

[0046] The first electric drive motor 14 is connected to the second transmission input shaft 26 via a gear chain comprising three fixed gears. The second transmission input shaft 26 is designed as a hollow shaft and surrounds the first transmission input shaft 24, at least partially.

[0047] Furthermore, the second transmission input shaft 26 is effectively connected to a sun gear of the planetary gear set RS. A planet carrier of the planetary gear set RS can be effectively connected to an intermediate shaft 30, on which a fixed gear of the third spur gear pair ST3 is arranged. This fixed gear is in mesh with a fixed gear arranged on the output shaft 28.

[0048] The first spur gear pair ST1 comprises a fixed gear arranged on the first transmission input shaft 24, which meshes with a loose gear arranged on the output shaft 28. The second spur gear pair ST2 also comprises a fixed gear arranged on the first transmission input shaft 24, which meshes with a loose gear arranged on the output shaft 28. The internal combustion engine 16 (not shown) is configured to be effectively connected to the first transmission input shaft 24. Furthermore, the output shaft 28 is configured to be connected to an output 32 of the hybrid transmission 18 (not specified).

[0049] The first switching element A is designed to switch the first spur gear pair ST1 in a driving manner and is combined with the second switching element B to form a double switching element.

[0050] The second switching element B is designed to switch the second spur gear pair ST2 in a drive-effective manner.

[0051] The third switching element C is designed as a single switching element and is configured to connect the third spur gear pair ST3 to the planet carrier of the planet gear set RS in a drive-effective manner.

[0052] The fourth switching element D is designed to connect the third spur gear pair ST3 to the second transmission input shaft 26 in a drive-effective manner.

[0053] The fourth switching element D is combined with a fifth switching element E to form a double switching element, wherein the fifth switching element E is designed to effectively connect the first transmission input shaft 24 to the second transmission input shaft 26, i.e., to lock the planetary gear set RS by effectively connecting the ring gear and the sun gear of the planetary gear set RS. It is understood that other possibilities exist for locking the planetary gear set RS, such as effectively connecting the planet carrier to the ring gear or the planet carrier to the ring gear.

[0054] In the example shown, the first electric drive motor 14 is connected to the hybrid transmission 18 on one of the transmission sides opposite the connection side of the combustion engine 16 (which is not shown).

[0055] In Fig. In a switching matrix 34, the first column shows the hybrid gear stages H1 to H3, an electric gear stage E, an electrodynamic superposition state EDA, and a charging-in-neutral state LiN. The second to sixth columns show the switching states of the switching elements A to E, where an "X" indicates that the respective switching element is closed, i.e., effectively connecting the associated transmission components. If no entry is present, it can be assumed that the corresponding switching element is open, i.e., not transmitting any drive power.

[0056] A first variant of the first hybrid gear stage H1.1 can be set up by inserting the third switching element C and the fourth switching element D.

[0057] A second variant of the first hybrid gear stage H1.2 can be set up by inserting the third switching element C and the fifth switching element E.

[0058] Inserting the first switching element A and the fourth switching element D sets up a first variant of the second hybrid gear stage H2.1.

[0059] A second variant of the second hybrid gear stage H2.2 can be set up by closing the first switching element A and the third switching element C.

[0060] Closing the first switching element A and the fifth switching element E establishes a third variant of the second hybrid gear stage H2.3.

[0061] Closing the first switching element A sets up a fourth variant of the second hybrid gear stage H2.4.

[0062] A first variant of the third hybrid gear stage H3.1 can be set up by closing the second switching element B and the fourth switching element D.

[0063] Closing the second switching element B and the third switching element C sets up a second variant of the third hybrid gear stage H3.2.

[0064] A third variant of the third hybrid gear stage H3.3 can be set up by closing the second switching element B and the fifth switching element E.

[0065] Closing the second switching element B sets up a fourth variant of the third hybrid gear stage H3.4.

[0066] A purely electric stage E can be set up by closing the fourth switching element D.

[0067] Closing the third switching element C establishes an electrodynamic superposition state EDA.

[0068] The state of charging-in-neutral, LiN, can be set by closing the fifth switching element E.

[0069] It is understood that the switching elements A to E are preferably designed as positive-locking switching elements, e.g., claw switching elements. It is further understood that the in Fig. The gear set shown in Figure 2 can be followed by a fixed gear ratio, for example in the form of another planetary gear set, or a spur gear stage. Furthermore, a differential is preferably connected downstream of the gear set.

[0070] For combustion engine or hybrid driving, three different hybrid driving gear stages are available for the combustion engine 16.

[0071] If only the fourth switching element D is closed, purely electric operation is possible, since the first electric drive motor 14 is directly connected to the output 32.

[0072] When only the third switching element C is closed, an EDA state is created at the planetary gear set RS. The internal combustion engine 16 is then connected to the ring gear of the planetary gear set RS, with the first electric drive motor 14 supporting the torque of the internal combustion engine 16 at the sun gear of the planetary gear set RS. The planet carrier of the planetary gear set RS is connected to the output 32 via the third spur gear pair ST3. This enables a so-called EDA forward start. From this EDA state, each of the three hybrid gear stages can be engaged for the internal combustion engine 16, because the third switching element C is closed in the first variant of the first hybrid gear stage H1.1, the second variant of the first hybrid gear stage H1.2, the second variant of the second hybrid gear stage H2.2, and the second variant of the third hybrid gear stage H3.2.

[0073] A shift from first to second 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 first variant of the first hybrid gear stage H1.1 to the first variant of the second hybrid gear stage H2.1. A shift from second to third gear can also be performed with output assistance from the first electric drive motor 14, with the fourth switching element D remaining closed. In this case, the transmission shifts from the first variant of the second hybrid gear stage H2.1 to the first variant of the third hybrid gear stage H3.1.

[0074] An electrodynamic load switching from the first variant of the first hybrid gear stage H1.1 to the first variant of the second hybrid gear stage H2.1 in hybrid operation can, for example, be carried out as follows. In the initial state, i.e., the first variant of the first hybrid gear stage H1.1, the third switching element C and the fourth switching element D are closed. A load reduction occurs at the third switching element C, and a simultaneous load increase occurs at the first electric drive motor 14. Then, the third switching element C is opened. The speed of the combustion engine 16 is reduced so that the first switching element A becomes synchronous. For this purpose, for example, another electric drive motor can be operated as a generator, or the combustion engine 16 can enter overrun mode. Then, the second switching element B can be engaged. The fourth switching element D remains closed during this switching process.

[0075] If only the fifth switching element E is closed, the first electric drive motor 14 can be connected to the combustion engine 16 independently of the output 32. The first electric drive motor 14 and the combustion engine 16 then rotate in a fixed ratio to each other. This allows the combustion engine 16 to be started using the first electric drive motor 14. Furthermore, 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 power a second electric drive motor 20, as shown in Fig. As shown in Figure 1, this could be the other axle of the vehicle, for example. A transition from the state of charging-to-neutral, LiN, is possible in all three hybrid gear stages because the fifth switching element E is closed in the second variant of the first hybrid gear stage H1.2, in the third variant of the second hybrid gear stage H2.3, and in the third variant of the third hybrid gear stage H3.3.

[0076] Is, as for example in Fig. As shown in Figure 1, an electric rear axle is present; using this combination, an all-wheel drive system can be created. For example, a DHT transmission, i.e., a Dedicated Hybrid Transmission, can be designed with the combustion engine 16 and the first electric drive motor 14 as a pure front-wheel drive, and an additional rear axle drive can be provided by the separate second electric drive motor 20.

[0077] The electrodynamic superposition state EDA in this case is a power-split E-CVT driving range for the combustion engine 16, in which battery-neutral operation is also possible. CVT driving range refers specifically to a continuously variable transmission (CVT) driving range.

[0078] In second and third gear, the first electric drive motor 14 can be decoupled, particularly in the fourth variant of the second hybrid gear stage H2.4 and the fourth variant of the third hybrid gear stage H3.4, when only the first switching element A or the second switching element B is closed. A particular advantage here is that no-load losses are avoided when the first electric drive motor 14 is not required. An example of such a mode is driving using only the combustion engine.

[0079] Furthermore, traction assistance can be provided by means of the second electric drive motor 20. The second electric drive motor 20 can, for example, support the traction force at the rear axle when switching operations are necessary in the hybrid transmission 18, during which the output 32 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.

[0080] In Fig. Figure 4a 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 of the shafts to the planetary gear set RS are reversed. In particular, the second transmission input shaft 26 is effectively connected to the ring gear of the planetary gear set RS, while the sun gear of the planetary gear set RS is effectively connected to the first transmission input shaft 24. The connection to the planet carrier of the planetary gear set RS remains the same.

[0081] Through the in Fig. According to the disclosed connection (4a), the first electric drive motor 14 can be operated at a lower balancing speed during electrodynamic starting (EDA) or electrodynamic switching (EDS). However, the first electric drive motor 14 must provide a higher supporting torque during electrodynamic starting (EDA) and electrodynamic switching (EDS). Furthermore, the first electric drive motor 14 can operate in generator mode for a shorter time during electrodynamic starting, since generator operation is terminated earlier with increasing speed than if the first electric drive motor 14 were connected to the sun gear of the planetary gear set RS.

[0082] In Fig. Figure 4b 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 4a, the arrangements of the fourth switching element D and the fifth switching element E are modified. The fourth switching element D is combined with the third switching element C to form a double switching element. The fifth switching element E is designed as a single switching element and is arranged between the planetary gear set RS and the second spur gear pair ST2.

[0083] 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 first spur gear pair ST1 and the second spur gear pair ST2 are interchanged with respect to their geometric order. Consequently, viewed from one connection side of the combustion engine 16 (not shown), the hybrid transmission 18 is arranged first with the second spur gear pair ST2, then with the second switching element B, which is combined with the first switching element A to form a double switching element, and then with the first spur gear pair ST1. The arrangement of the remaining transmission components corresponds to the arrangement shown in Figure 2. Fig. 2 shown.

[0084] 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 2, the fixed gears and ring gears of the first spur gear pair ST1 and the second spur gear pair ST2 are interchanged. Consequently, the output shaft 28 has only fixed gears, with the corresponding loose gears arranged on the first transmission input shaft 24.

[0085] It goes without saying that a combination of the two is also possible in the Fig. 5 and Fig. 6 disclosed embodiments. In other words, it is conceivable to exchange the loose gear and the fixed gear only in one of the two spur gear pairs ST1, ST2 and to exchange the spur gear pairs ST1 and ST2 with respect to their axial arrangement in the hybrid transmission 18.

[0086] In Fig. Figure 7 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. 2 hybrid transmissions 18 shown, wherein in Fig. Figure 8 shows the output 32 in more detail. The output 32 is formed by a fixed gear arranged between the second spur gear pair ST2 and the third spur gear pair ST3 on the output shaft 28. This fixed gear meshes with a fixed gear arranged on a differential and thus transmits drive power from the hybrid transmission 18 to the differential. The differential also has a differential shaft that penetrates a rotor shaft of the first electric drive motor 14. In other words, the first electric drive motor 14 is mounted on the differential shaft.

[0087] Furthermore, the hybrid transmission 18 has a transmission drive shaft 36, which is arranged parallel to the axis of the first transmission input shaft 24 and is effectively connected via a traction linkage to a fixed gear of the first transmission input shaft 24 located between the first spur gear pair ST1 and the second spur gear pair ST2. The transmission drive shaft 36 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.

[0088] Furthermore, a fixed gear for connecting another electric machine 38 is arranged on the transmission drive shaft 36. The other electric machine 38 is operatively connected to the transmission drive shaft 36 via a traction gear. Preferably, the other electric machine 38 can be designed as a high-voltage starter generator.

[0089] It is understood that the connection of the transmission drive shaft 36 to both the first transmission input shaft 24 and the further electric machine 38 can alternatively also be designed as a gear chain.

[0090] In Fig. Figure 8 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 36 comprises an internal combustion engine coupling K0. The internal combustion engine coupling K0 is designed to connect the transmission drive shaft 36 to the internal combustion engine 16 in a separably drive-effective manner. The internal combustion engine coupling K0 is arranged between the torsional vibration decoupling element and the two connecting gears of the transmission drive shaft 36, so that the additional electric machine 38 is always in drive connection with the first transmission input shaft 24.

[0091] In the Fig. In the example shown in section 8, the combustion engine coupling K0 is designed as a positive-locking switching element, for example as a claw coupling.

[0092] 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 combustion engine coupling K0 is designed as a friction-fit switching element.

[0093] 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 9 shows a towing start of the combustion engine 16. In particular, in an embodiment with a further electric machine 38, a combustion engine coupling K0 is useful.

[0094] 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.

[0095] 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 MARK LIST: 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 30 Intermediate shaft 32 Drive 34 switching matrix 36 Gearbox drive shaft 38 more electric machines AE switching elements K0 combustion engine clutch ST1 first spur gear pair ST2 second spur gear pair ST3 third spur gear pair

Claims

[1] 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 (32); exactly one planetary gear set (RS) connected to the first transmission input shaft (24) and the second transmission input shaft (26); exactly three pairs of spur gears (ST1, ST2, ST3) arranged in several gear set planes for forming gear stages; and several gear-shifting devices with exactly five shifting elements (A, B, C, D, E) for engaging gear stages, wherein the output shaft (28) is designed in a reduction gear design; and the planetary gear set (RS) can be decoupled and locked from the output shaft (28), and wherein the hybrid transmission has a transmission input shaft (36) which is effectively connected to the first transmission input shaft (24) and is arranged axially parallel to the first transmission input shaft (24), and / or the output shaft (28) is operatively connected to a differential of the output (32) in a drive-effective manner, wherein the differential comprises a differential shaft for transmitting drive power from the hybrid transmission (18) to wheels of the motor vehicle (10), which is arranged parallel to the axis of the output shaft (28) and is designed to support the first electric drive motor (14). [2] Hybrid transmission (18) according to claim 1, wherein the first transmission input shaft (24) can be effectively connected to the output shaft (28) via a first spur gear pair (ST1) and a second spur gear pair (ST2) of the spur gear pairs (ST1, ST2, ST3) to form the gear stages; and / or the planetary gear set (RS) and / or the second transmission input shaft (26) can be connected to the output shaft (28) via a third spur gear pair (ST3) of the spur gear pairs (ST1, ST2, ST3) to form the gear stages. [3] Hybrid transmission (18) according to claim 1 or 2, wherein the second transmission input shaft (26) is designed as a hollow shaft and surrounds the first transmission input shaft (24) at least partially. [4] Hybrid transmission (18) according to one of the preceding claims, wherein the planet carrier of the planet gear set (RS) can be connected to the output shaft (28) in a drive-effective manner; and the sun gear of the planetary gear set (RS) is effectively connected to the second transmission input shaft (26) and the ring gear of the planetary gear set (RS) is effectively connected to the first transmission input shaft (24); or the ring gear of the planetary gear set (RS) is effectively connected to the second transmission input shaft (26) and the sun gear of the planetary gear set (RS) is effectively connected to the first transmission input shaft (24). [5] 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), wherein the internal combustion engine coupling (K0) is arranged on the transmission drive shaft (36). [6] Hybrid transmission (18) according to one of the preceding claims, wherein a first switching element (A) is designed to connect the first transmission input shaft (24) to the output shaft (28) by means of a first spur gear pair (ST1); a second switching element (B) is designed to connect the first transmission input shaft (24) to the output shaft (28) by means of a second spur gear pair (ST2); a third switching element (C) is designed to connect the planetary gear set (RS) to the output shaft (28) by means of a third spur gear pair (ST3) in a driving manner; a fourth switching element (D) is designed to connect the second transmission input shaft (26) to the output shaft (28) by means of a third spur gear pair (ST3) in a driving manner; and / or a fifth switching element (E) is designed to lock the planetary gear set (RS). [7] Hybrid transmission (18) according to one of the preceding claims, wherein at least two spur gear pairs (ST1, ST2, ST3) are interchangeable with respect to their axial position for forming the gear stages; in the case of at least two spur gear pairs (ST1, ST2, ST3) for forming the gear stages, an arrangement of the respective loose gear is interchangeable with the arrangement of the respective fixed gear; and / or the output shaft (28) is designed without shifting elements. [8] 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. [9] 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) that 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). [10] Motor vehicle powertrain (12) according to claim 9, wherein the motor vehicle powertrain comprises a further electric machine (38) which is effectively connected to the first transmission input shaft (24) and which can be controlled as a starter generator for starting the internal combustion engine (16) and / or as a charging generator for charging an energy storage device (22). [11] Motor vehicle powertrain (12) according to claim 9 or 10, wherein an output (32) 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). [12] Method for operating a motor vehicle powertrain (12) according to any one of claims 9 to 11. [13] Motor vehicle (10) with: a motor vehicle powertrain (12) according to any one of claims 9 to 11; and an energy storage device (22) for storing energy to supply the first electric drive machine (14) and / or the second electric drive machine (20).

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