Hybrid Drive System

Abstract

It provides a simple and very compact structure, particularly in the axial direction, with many useful transmission functions. [Solution] The present invention relates to a hybrid drive system (1) having an internal combustion engine (2) and an electric motor (3), a first spur gear secondary transmission (B) and a second spur gear secondary transmission (A) from which output is taken via at least one secondary shaft (12), and a four-shaft planetary gear set (8) arranged coaxially to the crankshaft of the internal combustion engine (2), wherein a first shaft (8.1) is connected or can be connected to the crankshaft, a rotor (5) of the electric motor (3) is connected or can be connected to a second shaft (8.2) or is formed as the second shaft (8.2), a first input shaft (9) of the first spur gear secondary transmission (B) is connected to a third shaft (8.3) in a manner non-rotatable relative to the crankshaft, and a second input shaft (10) of the second spur gear secondary transmission (A) is connected to a fourth shaft (8.4) of the planetary gear set (8) in a manner non-rotatable relative to the crankshaft. The invention is characterized in that the first spur gear auxiliary transmission (B) and the second spur gear auxiliary transmission (A) each have exactly one spur gear pair (11, 14), and an interlock shift member (SK) for interlocking two of the shafts (8.1, 8.2, 8.3, 8.4) of the planetary gear set (8) against relative rotation is arranged between the two spur gear pairs (11, 14) as viewed in the axial direction (a) along the input shafts (9, 10).

Description

[Technical field]

[0001] The invention relates to a hybrid drive system with an internal combustion engine and an electric motor of the kind defined in detail in the preamble of claim 1.

[0002] Patent Document 1 listed below discloses a hybrid drive system including an internal combustion engine, an electric motor, and a transmission device having a four-shaft planetary gear set and two spur gear sub-transmission devices.

[0003] A hybrid drive system as mentioned at the outset with an internal combustion engine and an electric motor is described, for example, in the Applicant's DE 10 200 03 133 A1, in which a four-shaft planetary gear set is used, via which the electric motor and the internal combustion engine are connected to the transmission of the hybrid drive system.

[0004] Furthermore, in this connection, reference may be made to the following document WO 2005 / 023363, which also discloses a hybrid drive system with a four-shaft planetary gear set and two spur gear sub-transmissions, the output to the differential being realised centrally between the two sub-transmissions via a countershaft. Further hybrid drive systems with four-shaft planetary gear sets are known from US Pat. No. 5,399,623, US Pat. No. 5,499,633, US Pat. No. 5,599,623 and US Pat. No. 5,629,645.

[0005] The first prior art structure is highly complex in terms of the realization of many functions, while the second prior art structure is certainly simpler, but requires a lot of construction space, especially in the axial direction, i.e. in the direction of the main transmission shaft and the input shafts of the two spur gear secondary transmissions. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] DE 10 2013 221 461 A1 [Patent Document 2] German Patent Application Publication No. 10 2017 006 082 A1 [Patent Document 3] US Patent Application Publication No. 2013 / 0102430 A1 [Patent Document 4] US Patent Application Publication No. 2009 / 0209381 A1 [Patent Document 5] DE 10 2006 050 598 A1 [Patent Document 6] US Patent Application Publication No. 2010 / 0261565 A1 Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the invention is to provide a simple and, in particular axially, very compact construction which provides a number of useful transmission functions. [Means for solving the problem]

[0008] According to the invention, this problem is solved by a hybrid drive system with the features of claim 1, and here in particular with the features of claim 1. Advantageous embodiments and developments of the hybrid drive system according to the invention emerge from the dependent claims.

[0009] The hybrid drive system according to the invention is used in particular as a vehicle drive. The hybrid drive system comprises an internal combustion engine, one or at least one electric motor, and a four-shaft planetary gear set. The four-shaft planetary gear set is arranged coaxially with the crankshaft of the internal combustion engine. Furthermore, two mechanical sections are provided via a first spur gear sub-transmission and a second spur gear sub-transmission, whereby output energy is output via one section or the other section or both sections. For this purpose, a first shaft of the planetary gear set is connected to the crankshaft of the internal combustion engine or can be connected, preferably via a separating clutch and, if necessary, a torsional vibration damper. A rotor of the electric motor is connected or can be connected to a second shaft of the planetary gear set. For example, the rotor of the electric motor forms the internal gear of the planetary gear set or is directly connected thereto, so that the rotor of the electric motor can also directly form this second shaft of the planetary gear set. The first input shaft of the first spur gear sub-transmission and the second input shaft of the second spur gear sub-transmission in this case form the third and fourth shafts of the planetary gear set or are preferably connected to the planetary gear set in a non-rotatable manner.

[0010] According to the invention, in order to achieve a simple and compact construction, each of the first and second spur gear sub-transmissions has exactly one spur gear pair. The two spur gear pairs, one of which is the spur gear pair of the first spur gear sub-transmission and the other of which is the spur gear pair of the second spur gear sub-transmission, are arranged relative to one another in such a way that, as viewed in the axial direction along the two input shafts of each spur gear sub-transmission, an interlock shift member for interlocking the two shafts of the planetary gear set is arranged between the two spur gear pairs. That is to say, the planetary gear set has an interlock shift member that can appropriately connect its two shafts, so that the planetary gear set is interlocked and thus rotates as a unit without its components moving relative to one another. This interlock shift member is arranged axially between the two spur gear pairs and thus axially between the two spur gear sub-transmissions. This results in a very compact construction in the axial direction. By using the four-shaft planetary gear set of the internal combustion engine and the electric motor in the above-described arrangement, a large number of functions can be simply and efficiently realized with the hybrid drive system of the present invention.

[0011] The aforementioned four shafts of the four-shaft planetary gear set are arranged coaxially with each other. Thus, the rotation axes of the aforementioned four shafts coincide with one rotation axis of the four-shaft planetary gear set. The term "shaft" used below refers to the rotation axis of the four-shaft planetary gear set. This rotation axis of the four-shaft planetary gear set is considered here as the main rotation axis. The term "axial direction" used below also refers to the direction of the main rotation axis. Since the four-shaft planetary gear set is arranged coaxially with the crankshaft of the internal combustion engine, the rotation axis of the crankshaft of the internal combustion engine also coincides with the main rotation axis.

[0012] The two spur gear sub-transmissions and the four-shaft planetary gear set together form a transmission, which is arranged between the internal combustion engine and the axle gears, also called differential, in terms of the torque flow from the internal combustion engine. Similarly, the transmission is arranged between the electric motor and the axle gears in terms of the torque flow from the electric motor.

[0013] In the sense of the present invention, non-rotatable is understood to mean that two pivotally supported parts are connected or joined in a non-rotatable manner, the two parts being arranged coaxially with respect to one another and connected to one another in such a way that they rotate with the same angular speed. In the context of the present invention, reference is also made to a non-rotatable connection of two parts when, for example, a vibration or torsion damper is arranged between the two parts, which allows only small twisting between the two parts, especially when the rotation speed changes suddenly.

[0014] A particularly advantageous arrangement of the components of the hybrid drive system is obtained if the internal combustion engine, the four-shaft planetary gear set and the two spur gear auxiliary transmissions are arranged one after the other in the aforementioned sequence in terms of the torque flow from the internal combustion engine. Thus, during appropriate operation of the hybrid drive system, torque is introduced from the internal combustion engine first into the four-shaft planetary gear set and then from the four-shaft planetary gear set into one of the two spur gear auxiliary transmissions. In terms of torque flow, an axle gear is preferably arranged downstream of the two spur gear auxiliary transmissions.

[0015] In terms of the torque flow from the electric motor, the four-shaft planetary gear set is advantageously arranged after the electric motor and before the two spur gear sub-transmissions.

[0016] In order to achieve interlocking of the components even when the speeds of the corresponding shafts of the planetary gear set are different, the interlocking shifting member itself can also be configured as a friction clutch, for example. According to a particularly preferred and advantageous embodiment, however, the interlocking shifting member can be configured as a positively-locking clutch. In particular, in such a positively-locking clutch, all kinds of synchronizers are omitted, and a particularly simple and compact construction is achieved. This positively-locking clutch operates almost without wear, and the rotational speed can be adapted as required by using an electric motor which is connected or can be connected to the second shaft of the four-shaft planetary gear set, so that even with such a positively-locking clutch as an interlocking shifting member, comfortable and reliable shifting is achieved.

[0017] According to a very preferred development of the hybrid drive according to the invention, an output gear can be provided on the countershaft, which is non-rotatably connected to exactly one countershaft, and which is arranged axially overlapping the planetary gear set. This single countershaft allows a very compact construction of the transmission in the direction transverse to the axial direction. By axially overlapping the output gear, which is non-rotatably connected to the countershaft and is therefore formed as a fixed gear, with the planetary gear set, a very compact construction in the axial direction is achieved, in contrast to the prior art. This allows the differential to be moved very close to the internal combustion engine, which advantageously promotes an optimal utilization of the construction space that is generally present in a vehicle. This allows an installation in particular in the direction transverse to the direction of travel.

[0018] The expression that two elements are arranged "axially overlapping" means within the scope of the present invention that the two elements are each arranged at least partially in the same axial region or section, the axial region being defined by a coordinate interval about a reference axis, here the main axis of rotation, the coordinates in the other two spatial directions being arbitrary.

[0019] According to one advantageous embodiment of the hybrid drive system according to the invention, the internal combustion engine or its crankshaft can be connected to the first shaft of the planetary gear set in a rotationally fixed manner via a separating clutch. Here, a dual-mass flywheel can be provided for damping or absorbing torsional vibrations, either complementary to the separating clutch or compactly integrated therewith. Alternative designs of the torsional vibration damper are also conceivable. The separating clutch itself allows a purely electric operation of the hybrid drive system by separating the transmission or the planetary gear set from the internal combustion engine, which correspondingly increases the possibilities for increasing the functionality of the hybrid drive system according to the invention. Here, the separating clutch itself can be designed in a positive or frictional manner. In particular, the separating clutch can also be realized in a positively locked manner without synchronization, in order to ensure that its construction is particularly simple and compact.

[0020] At least one rotor gear of the electric motor or of the rotor of the electric motor is arranged overlapping with the planetary gear set when viewed in the axial direction. This arrangement of the electric motor, which is arranged in particular axially parallel to the input shaft of the two spur gear auxiliary transmissions and to the crankshaft, also allows for a very compact construction in the axial direction. By rotor gear is meant a gear which is connected to the rotor in a non-rotatable manner, via which the torque from the electric motor can be transmitted to the four-shaft planetary gear set.

[0021] According to an advantageous development, the connection of the electric motor can here take place via further transmission elements, for example via a spur gear transmission, a belt drive, a chain drive or the like.

[0022] However, alternatively, the electric motor can also be arranged coaxially, for example coaxially with the planetary gear set, in which case, inter alia, the internal gear of the planetary gear set forms a second shaft which is connected with the rotor gear of the electric motor or which, in such a coaxial arrangement, directly forms part of the rotor of the electric motor.

[0023] In a very preferred development of the hybrid drive system according to the invention, the shift member for the first spur gear auxiliary transmission can be arranged coaxially to the countershaft and axially between the spur gear pairs. Such a coaxial arrangement of the shift member for the first spur gear auxiliary transmission to the countershaft uses a fixed gear in the region of the input shaft of the first spur gear pair and, correspondingly, an idler gear on at least one countershaft, according to the above-mentioned configuration, exactly one countershaft. In principle, such a shift member can be arranged coaxially on the countershaft in any axial position. It is particularly preferred that the shift member is provided between two spur gear pairs.

[0024] Here, coaxial in the sense of the present invention is understood to mean that one pivotally supported part is mounted coaxially with respect to another pivotally supported part, for example an axle, whereby the rotation axes of the two parts respectively coincide or are aligned.Furthermore, according to the present invention, a gear or spur gear pair is understood to be two mutually engaged gears or spur gears having parallel axes of rotation and arranged in a common plane, called the gearset plane, with respect to a plane perpendicular to their axes of rotation.

[0025] According to a very preferred development, the same applies to the second shift member for the second spur gear auxiliary transmission, which is in particular likewise arranged coaxially to the auxiliary shaft, in particular arranged axially between the spur gear pairs. This arrangement thus results in an arrangement with fixed gears in the region of the respective input shafts in the two spur gear auxiliary transmissions, which include an interlocking shift member between the fixed gears in the axial direction and in particular a corresponding idler gear on exactly one auxiliary shaft. The two shift members are preferably arranged axially between the spur gear pairs. This means that they utilize the same construction space in the axial direction as the interlocking shift members, so that no additional construction space is required in the axial direction.

[0026] In this case, according to a very advantageous development of this idea, the two shift members can have a common synchronizer, which results in a construction that is as simple as possible and also compact in the axial direction.In particular, according to a very advantageous development of this variant of the hybrid drive system according to the invention, a common sliding sleeve can be provided, in order to further reduce the costs in terms of components and actuator systems.

[0027] In an advantageous embodiment of the hybrid drive system according to the invention, the first shaft of the four-shaft planetary gear set is the first sun gear, the second shaft is the internal gear, the third shaft is the second sun gear and the fourth shaft is the carrier, here the dual carrier. This means that the internal gear can be used accordingly as the second shaft for connecting the electric motor, so that a connection via a transmission element such as a spur gear transmission, a belt drive or a chain drive is also conceivable. In this case, the rotation axis of the rotor of the electric motor is axially parallel to the rotation axis of the crankshaft of the internal combustion engine. Alternatively, it is also possible to integrate the planetary gear set in the electric motor accordingly, so that the rotor of the electric motor forms the internal gear of the four-shaft planetary gear set and the electric motor is arranged coaxially to the main rotation axis of the transmission. In this case, the drive is provided by the internal combustion engine via the first sun gear and the first shaft, and the second sun gear and the carrier correspondingly provide the power output and form the input shaft of two spur gear sub-transmissions which can be connected non-rotatably with respect to one another, in particular via an interlocking shift member.

[0028] According to an alternative, but slightly more advantageous embodiment, the first shaft of the planetary gear set can be the internal gear, the second shaft can be the second sun gear, the third shaft can be the carrier and the fourth shaft can be the first sun gear, also with this arrangement the advantageous operation of the hybrid drive according to the invention with a four-shaft planetary gear set is achieved.

[0029] Finally, the four-shaft planetary gear set in the two variants described above is configured in such a way that as soon as the two spur gear sub-transmissions connected to the third and fourth shafts are actively shifted, the first shaft represents a sum shaft with respect to the third and fourth shafts, i.e. their corresponding shift members are closed and the electric motor does not deliver a significant torque. The third shaft of the planetary gear set, which is connected non-rotatably to the first spur gear sub-transmission, is in this case actively shifted to a gear stage in the first spur gear sub-transmission and represents a sum shaft with respect to the second and first shafts, and the electric motor delivers a significant torque, as soon as the shift member of the other spur gear sub-transmission is opened.

[0030] Further advantageous embodiments of the hybrid drive system according to the invention emerge from two embodiments which are described in more detail below with reference to the respective figures. [Brief description of the drawings]

[0031] [Figure 1] FIG. 1 is a schematic diagram of a first possible embodiment of a hybrid drive system according to the invention. [Diagram 2] FIG. 2 illustrates a portion of an alternative embodiment of a hybrid drive system according to the present invention. [Diagram 3] FIG. 3 is a diagram showing a shift table for explaining possible states of the hybrid drive system according to the present invention in FIGS. 1 and 2. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0032] 1 shows a hybrid drive system 1, which includes a diagrammatically illustrated internal combustion engine 2 and an electric motor 3 with a stator 4 and a rotor 5. The rotor 5 is connected in a rotationally fixed manner to a rotor gear 6, which is connected via an intermediate gear 7 as a transmission member to a four-shaft planetary gear set 8. Here, the four-shaft planetary gear set 8 comprises a first shaft or member 8.1, which here is formed by a first sun gear. Here, a second member 8.2 is connected to the intermediate gear 7 and is formed by an internal gear of the planetary gear set 8. In addition to these two shafts 8.1 and 8.2, a third shaft or member 8.3 of the planetary gear set 8 is formed by a second sun gear and is connected in a rotationally fixed manner to a first input shaft 9 of the first spur gear auxiliary transmission B. The carrier (web) or dual carrier (double web) as the fourth shaft or fourth member 8.4 of the planetary gear set 8 is connected to the second input shaft 10 of the second spur gear auxiliary transmission A so as to be non-rotatable relative to the second input shaft 10.

[0033] A first shaft or first member 8.1 of the planetary gear set 8 can be connected to a crankshaft (not shown) of the internal combustion engine 2 via a separating clutch K0 and, optionally, a torsional vibration damper 13. When the separating clutch K0, which can in particular be configured as a positive-locking clutch without synchronization, is closed, the internal combustion engine 2 or its crankshaft can be coupled to the first shaft 8.1 as required.

[0034] A first fixed gear FB, arranged coaxially and non-rotatably on the first input shaft 9, is driven via the first input shaft 9 by a first idler gear LB, which together form a spur gear pair 11. Here, this spur gear pair 11 is a single spur gear pair of a first spur gear sub-transmission B, whose idler gear LB is arranged coaxially on a countershaft 12 and can be connected to the countershaft 12 non-rotatably via a shift member SB, if necessary. The second spur gear sub-transmission A comprises a fixed gear FA on a second input shaft 10, which is connected to the fourth shaft 8.4 of the planetary gear set 8, and which is realized as a hollow shaft coaxially relative to the first input shaft 9 and formed around the first input shaft. In this case, an idler gear LA complements the spur gear pair 14 and thus the second spur gear sub-transmission A, which comprises only this one spur gear pair 14. Via a shift member SA, this idler gear LA can also be connected to the countershaft 12, if necessary, in a manner that prevents it from rotating relative to the countershaft.

[0035] The countershaft 12 itself supports an output gear 15 which is arranged partially overlapping the planetary gear set 8 in an axial direction a which is always related to the axis of rotation of the crankshaft of the internal combustion engine and thus to the main axis of rotation of the spur gear countertransmission A, B. This output gear 15 is engaged with a differential 16, also called axle gear, indicated here only diagrammatically, via which the drive shafts of the vehicle equipped with the hybrid drive system 1 are driven.

[0036] The two shift members SA, SB are combined in the embodiment shown here into one combined special shift member, which may be called SAB. This special shift member comprises in the embodiment shown here a common synchronizer 17 and a common sliding sleeve 18. Although it is in principle conceivable to configure the shift members as friction shift members, this variant with the configuration of the shift members SA and SB as combined shift members with a positively coupled shift part via a single actuator and a common sliding sleeve 18 is ideal. As regards the arrangement, it is preferred, inter alia, to arrange them between the two spur gear pairs 11, 14. Various shift positions can be provided: on the one hand, the first idler gear LB can be connected to the countershaft 12 and thus to the output via the output gear 15; the other idler gear LA can be connected in the same way. Furthermore, two idler gears can be connected to the countershaft 12. Optionally, another shift position is also conceivable in which the sliding sleeve 18 is moved so that it is still connected to one of the two idler gears, for example the idler gear LA, so that there is no connection with the countershaft 12 and thus to the neutral gear which is decoupled from the output.

[0037] Two of the members of the planetary gear set 8, for example in the embodiment shown here the third shaft 8.3 and the fourth shaft 8.4 or the first input shaft 9 and the second input shaft 10 which are connected thereto in such a way that they cannot rotate relative to each other, can be connected to each other via an interlocking shift member SK, which is also formed here in particular as a non-synchronous positively-locking shift member. Due to the corresponding rotational speeds of the members, a relative movement between the members of the planetary gear set can be realized by the connection of the carrier as the fourth member 8.4 with the second sun gear as the third member 8.3. Since the planetary gear set 8 rotates as one unit, the shift member SK is generally referred to as an interlocking shift member.

[0038] An alternative construction of the hybrid drive system 1 is described on the basis of FIG. 2, which shows a cross section of the hybrid drive system 1, in which, unlike FIG. 1, the differential 16 is not shown. Here, all relevant parts are given the same reference numbers as above, and only the differences are described again. Here, the planetary gear set 8 is formed in such a way that the first shaft 8.1 of the planetary gear set 8, which can be connected to the internal combustion engine 2 via a separating clutch K0, is formed by an internal gear. The second shaft 8.2, which is connected to the electric motor 3, is formed by a second sun gear. The third shaft 8.3 is here a carrier or dual carrier and, as a third part, is again connected to the first input shaft 9 of the first spur gear secondary transmission B. The remaining part of the planetary gear set 8 is the first sun gear and, as a fourth shaft 8.4, is correspondingly connected to the second input shaft 10 of the second spur gear secondary transmission B.

[0039] The two spur gear auxiliary transmissions A, B have essentially the same structure as shown in FIG. 1. In this case, the two shift members SB and SA for connecting the idler gears LB and LA to the auxiliary shaft 12 have a common synchronizer 17, but have separate sliding sleeves 18A, 18B and actuators, so that the shift member SA or the shift member SB or both shift members SA and SB can be actuated separately from one another. In the shifting variant of the two sliding sleeves 18A, 18B shown here, neutral gear is entered and the drive is decoupled from the output gear 15 or the auxiliary shaft 12. In addition to these differences, the interlocking shift member SK is formed as a friction clutch in the embodiment shown here. All three differences can each be combined individually with the corresponding embodiment variants based on the embodiment of FIG. 1. That is, for example, a configuration of the combined shift member SAB with the illustrated arrangement of the planetary gear set 8 or a configuration of the interlocking shift member SK as a friction clutch with the arrangement of the planetary gear set 8 shown in FIG. 1 is conceivable.

[0040] All of the above-mentioned variants of the embodiment of the hybrid drive system 1 realize various states which are explained below on the basis of the table in Fig. 3. In this table, a closed clutch or a closed shift member or the corresponding state entered in the table is represented by a filled circle, respectively.

[0041] A first combination state, in which both the internal combustion engine and the electric motor can act on the hybrid drive system 1, is designated EVT1. In this case, the torques or speeds of the internal combustion engine 2 and the electric motor 3 are superimposed in the planetary gear set 8, while the shift member SA is closed and the shift member SB is opened. This state can be entered, for example, in order to drive the vehicle in hybrid mode with the hybrid drive system 1. Here, both the internal combustion engine 2 and the electric motor 3 are involved. Due to the torque from the internal combustion engine 2 and the generator operation of the electric motor 3 at the start, the torque can continue to increase and reach the drive, with the generator output at the electric motor 3 being correspondingly reduced depending on the drive control of the electric motor 3. This allows an electrodynamic start-up to be realized. In a further process, the electric motor 3 can also be operated as a motor. In addition to this start-up of the vehicle with the hybrid drive system 1, the first EVT mode EVT1 is used, among other things, for speed synchronization in the shift member SB as well as for active gear ratio adjustment, in particular when changing from the first gear to the second gear. This is described in more detail below. In first gear, the planetary gear set 8 is correspondingly locked by closing the interlock shift member SK, either via a positively-locking clutch member or, as suggested in FIG. 2, via a frictionally-locking clutch member which here forms an interlock shift member, when the rotational speeds of the involved parts are synchronized and made equal by the electric motor 3.

[0042] Due to the synchronization in the region of the shift member SB already described above, when switching from first to second gear, on the one hand the interlock shift member SK is opened and, in addition to the shift member SA, the shift member SB is also closed, or, in the case of the common sliding sleeve 18, this sliding sleeve is moved into the corresponding position.

[0043] Subsequently, in order to shift from second gear to third gear, the shift member SA is opened or the common sliding sleeve 18 is moved accordingly, and at the same time the interlock shift member SK is closed again, so that the two input shafts 9, 10 and the planetary gear set 8 are interlocked accordingly.

[0044] In the second EVT mode, the interlock shift member SK is open, the shift member SA is open and the shift member SB is closed, and the speed of the internal combustion engine 2 and the torque of the electric motor 3 are correspondingly superimposed in the planetary gear set 8. This second EVT mode EVT2 is used in particular as an overdrive mode and provides a correspondingly "long" transmission ratio. This second EVT mode EVT2 is likewise used for active transmission ratio adjustment and can also be used for speed synchronization in the interlock shift member SK when changing from second to third gear, if the interlock shift member SK is designed as a positively-locked shift member without synchronization, as can be seen from FIG. 1. In this mode too, the electric motor can be driven either by a generator or by a motor.

[0045] The further states E1, E2 and E3 are electrical gears which are realised in the case of E1 with the separating clutch K0 open and the shift members SA and SB engaged. On switching from E1 to E2 the shift member SB is opened and the planetary gear set 8 is interlocked, on further switching to E3 the shift member SA is opened and the shift member SB is correspondingly closed.

[0046] As mentioned above, the variants of the two described embodiments of the hybrid drive system according to the invention can have a "neutral" position in which the countershaft and thus the output are decoupled via the output gear 15. For this, the two shift members SA and SB shown in FIG. 2 are operated in such a way that the respective sliding sleeves 18A and 18B are connected only to one of the idler gears LA, LB or, as can be seen from FIG. 2, to the common synchronizer 17 but not to the respective idler gears LA, LB. In the configuration shown in FIG. 1, this neutral position can be achieved by the sliding sleeve 18 being correspondingly displaced, for example, in the direction of the idler gear LA so that it is still connected to this idler gear LA, in which respect it is also suggested in the drawing that in FIG. 1 the idler gear LA is formed with a corresponding protrusion around the countershaft 12, which results in the required construction space.

Claims

1. The invention relates to an internal combustion engine (2) and an electric motor (3), a first spur gear auxiliary transmission (B) and a second spur gear auxiliary transmission (A) from which an output is taken via at least one auxiliary shaft (12), and a four-shaft planetary gear set (8) arranged coaxially with a crankshaft of the internal combustion engine (2) and having a first shaft (8.1), a second shaft (8.2), a third shaft (8.3) and a fourth shaft (8.4), such that the first shaft (8.1) can introduce torque from the internal combustion engine (2) to the planetary gear set (8) via the first shaft (8.1). a rotor (5) of the electric motor (3) is connected or connectable to a second shaft (8.2) such that a torque from the rotor (5) can be introduced to the planetary gear set (8) via the second shaft (8.2); a first input shaft (9) of the first spur gear auxiliary transmission (B) is connected to the third shaft (8.3) in a manner that the torque from the rotor (5) can be introduced to the planetary gear set (8) via the second shaft (8.2); a second input shaft (10) of the second spur gear auxiliary transmission (A) is connected to the fourth shaft (8.4) in a manner that the torque from the rotor (5) can be introduced to the planetary gear set (8) via the second shaft (8.2); The first spur gear sub-transmission device (B) and the second spur gear sub-transmission device (A) each have exactly one spur gear pair (11, 14); an interlock shift member (SK) for connecting two of the shafts (8.1, 8.2, 8.3, 8.4) of the planetary gear set (8) in such a way that they cannot rotate relative to each other is disposed between two spur gear pairs (11, 14) as viewed in an axial direction (a) relative to the rotation axis of the input shaft (9, 10); With respect to the flow of torque from the internal combustion engine (2), the internal combustion engine (2), the four-shaft planetary gear set (8) and the two spur gear sub-transmissions (A, B) are arranged one behind the other in the aforementioned order. A hybrid drive system (1).

2. The interlocking shift member (SK) is designed as a positively-locking clutch. A hybrid drive system (1) according to claim 1.

3. Exactly one of the countershafts (12) is provided with an output gear (15) which is connected to said countershaft (12) in a non-rotatable manner relative thereto, The output gear (15) is arranged to overlap with the planetary gear set (8) in the axial direction (a). A hybrid drive system (1) according to claim 1 or 2.

4. The crankshaft of the internal combustion engine (2) can be connected to the first shaft (8.1) of the planetary gear set (8) in a rotationally non-rotatable manner via a separating clutch (K0). A hybrid drive system (1) according to any one of claims 1 to 3.

5. A rotor gear (6) connected to the electric motor (3) or the rotor (5) of the electric motor (3) so as not to rotate relative to the electric motor (3) is arranged so as to overlap the planetary gear set (8) when viewed in the axial direction (a). A hybrid drive system (1) according to any one of claims 1 to 4.

6. The electric motor (3) is connected to the second shaft (8.2) of the planetary gear set (8) via another transmission member (7). A hybrid drive system (1) according to any one of claims 1 to 5.

7. A first shift member (SB) is arranged coaxially with the at least one countershaft (12) and between the spur gear pair (11, 14) in the axial direction (a). A hybrid drive system (1) according to any one of claims 1 to 6.

8. A second shift member (SA) is arranged coaxially with the at least one countershaft (12) and between the spur gear pair (11, 14) in the axial direction (a). A hybrid drive system (1) according to claim 7.

9. The two shift members (SA, SB) have a common synchronizer (17). A hybrid drive system (1) according to claim 8.

10. The two shift members (SA, SB) have a common sliding sleeve (18). A hybrid drive system (1) according to claim 9.

11. The first axis (8.1) of the planetary gear set (8) is formed by a first sun gear of the planetary gear set (8), the second axis (8.2) is formed by an internal gear of the planetary gear set (8), the third axis (8.3) is formed by a second sun gear of the planetary gear set (8) and the fourth axis (8.4) is formed by a carrier of the planetary gear set (8). A hybrid drive system (1) according to any one of the preceding claims.

12. The first axis (8.1) of the planetary gear set (8) is formed by an internal gear of the planetary gear set (8), the second axis (8.2) is formed by a second sun gear of the planetary gear set (8), the third axis (8.3) is formed by a carrier of the planetary gear set (8) and the fourth axis (8.4) is formed by a first sun gear of the planetary gear set (8). A hybrid drive system (1) according to any one of the preceding claims.

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