Hybrid Transmission Assembly, Motor Vehicle Powertrain, and Motor Vehicle

Abstract

A hybrid transmission assembly for a motor vehicle powertrain may include an input shaft arrangement including a first input shaft of a first sub-transmission and a second input shaft of a second sub-transmission. The assembly may further include a first electric machine axially parallel and connected to the first input shaft, and a second electric machine axially parallel and connected to the second input shaft. The input shaft arrangement, viewed axially, is in a center of four quadrants. An axis of the first electric machine is in the first quadrant and, or alternatively, an axis of the second electric machine is in the fourth quadrant.

Claims

1-15: (canceled)

16. A hybrid transmission assembly (16) for a motor vehicle powertrain (10), comprising: an input shaft arrangement (24, 26) including a first input shaft (24) of a first sub-transmission (32) and a second input shaft (26) of a second sub-transmission (34); a first electric machine (56) connected to the first input shaft (24) and axially parallel to the first input shaft (24); and a second electric machine (60) connected to the second input shaft (26) and axially parallel to the second input shaft (26), wherein the input shaft arrangement (24, 26), viewed axially, is in a center of four quadrants (I, II, III, IV), a first quadrant (I) of the four quadrants being above the input shaft arrangement (24, 26) and on a first longitudinal side of the input shaft arrangement (24, 26), a second quadrant (II) of the four quadrants being below the input shaft arrangement (24, 26) and on the first longitudinal side of the input shaft arrangement (24, 26), a third quadrant (III) of the four quadrants being below the input shaft arrangement (24, 26) and on a second longitudinal side of the input shaft arrangement (24, 26), and a fourth quadrant (IV) of the four quadrants being above the input shaft arrangement (24, 26) and on the second longitudinal side of the input shaft arrangement (24, 26), and wherein one or both of an axis (A4) of the first electric machine (56) is in the first quadrant (I) and an axis (A5) of the second electric machine (60) is in the fourth quadrant (IV).

17. The hybrid transmission assembly of claim 16, further comprising a countershaft (28), a power distribution unit (18), and an output gear set (30), wherein the first input shaft (24) and the second input shaft (26) are connected to the countershaft (28) via at least one engageable gear set (36, 38 42; 48, 50), and wherein the countershaft (28) is connected to the power distribution unit (18) via the output gear set (30).

18. The hybrid transmission assembly of claim 17, wherein one or more of: an axis (A3) of the power distribution unit (18) is in the second quadrant (II); an axis (A2) of the countershaft (28) is in the second quadrant (II); and the axis (A2) of the countershaft (28) is closer to the third quadrant (III) than the axis (A3) of the power distribution unit (18).

19. The hybrid transmission assembly of claim 16, further comprising actuating units (S1-S4) in the third quadrant (III), the actuating units being axially displaceable for one or more of engaging engageable gear sets (36, 38 42; 48, 50), actuating a dual-clutch assembly (14) associated with the hybrid transmission assembly (16), and actuating a third clutch (K3).

20. The hybrid transmission assembly of claim 16, wherein one or both of: the first electric machine (56) is connected to the first input shaft (24) via an engageable gear set (38; 42″) of the first sub-transmission (32); and the second electric machine (60) is connected to the second input shaft (26) via an engageable gear set (50) of the second sub-transmission (34).

21. The hybrid transmission assembly of claim 20, wherein one or both of: the engageable gear set (42″) of the first sub-transmission (32) is associated with a highest gear step (5) of the first sub-transmission (32); and the engageable gear set (50) of the second sub-transmission (34) is associated with a highest gear step (4) of the second sub-transmission (34).

22. The hybrid transmission assembly of claim 20, wherein one or both of: the engageable gear set (38; 42″) of the first sub-transmission (32) is at a first axial end of the hybrid transmission assembly (16); and the engageable gear set (50) of the second sub-transmission (34) is at a second axial end of the hybrid transmission assembly (16).

23. The hybrid transmission assembly of claim 16, wherein one or both of: the first electric machine (56) is connected to a first gearwheel (70) at the first input shaft (24) via a first intermediate gear (59); and the second electric machine (60) is connected to a second gearwheel (72) at the second input shaft (26) via a second intermediate gear (63).

24. The hybrid transmission assembly of claim 16, wherein the first sub-transmission (32) has three gear sets (36, 38, 42), each of the three gear sets (36, 38, 42) of the first sub-transmission (32) being associated with a respective, odd forward gear step, and wherein the second sub-transmission (34) has two or three gear sets (48, 50), each of the two or three gear sets (48, 50) of the second sub-transmission being associated with a respective, even forward gear step.

25. The hybrid transmission assembly of claim 16, wherein the first electric machine (56) and the second electric machine (60) are identical.

26. The hybrid transmission assembly of claim 16, further comprising: a third clutch (K3), the first sub-transmission (32) being connectable to the second sub-transmission (34) via the third clutch (K3); and a gearshift clutch (E; C), a gear set (42; 38″) of one of the first and second sub-transmissions (32) being engageable by the gearshift clutch (E; C), wherein the third clutch (K3) and the gearshift clutch (E; C) form a gearshift clutch assembly (66; 66″).

27. A hybrid powertrain, comprising: a dual-clutch assembly (14) including a first clutch (K1) and a second clutch (K2), the first and second clutches (K1, K2) having a shared input element (EG) connectable to an internal combustion engine (12), the first clutch (K1) including a first output element (AG1), and the second clutch (K2) including a second output element (AG2); and the hybrid transmission assembly of claim 16, wherein the first input shaft (24) is connected to the first output element (AG1), and wherein the second input shaft (26) is connected to the second output element (AG2).

28. The hybrid powertrain of claim 27, wherein one or more of the first clutch (K1), the second clutch (K2), a third clutch (K3), and/or at least one gearshift clutch (A, B, C, D, E) is a dog clutch.

29. The hybrid powertrain of claim 27, wherein the first clutch (K1) is a friction clutch, and wherein the second clutch (K2) is a form-locking dog clutch.

30. A motor vehicle (80), comprising the hybrid transmission assembly of claim 16, wherein the hybrid transmission assembly (16) is aligned transversely to a longitudinal axis (82) of the motor vehicle (80) and is installed in the motor vehicle (80) at a front end of the motor vehicle to drive front wheels of the motor vehicle or at a rear end of the motor vehicle to drive rear wheels of the motor vehicle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0091] Exemplary embodiments of the invention are represented in the drawing and are explained in greater detail in the following description, wherein

[0092] FIG. 1 shows a diagrammatic gear set representation of an embodiment of a hybrid drive train;

[0093] FIG. 2 shows a diagrammatic power flow representation of a further embodiment of a hybrid drive train;

[0094] FIG. 3 shows a schematic of a further embodiment of a hybrid drive train;

[0095] FIG. 4 shows an alternative embodiment of a dual-clutch assembly;

[0096] FIG. 5 shows a gearshift table for an internal combustion engine-driven operation and a hybrid operation of the hybrid drive train from FIG. 1;

[0097] FIG. 6 shows a gearshift table for an electric motor-driven operation by the first electric machine;

[0098] FIG. 7 shows a gearshift table for an electric motor-driven operation by the second electric machine;

[0099] FIG. 8 shows an axial view of a preferred embodiment of a hybrid drive train with four quadrants represented; and

[0100] FIG. 9 is a lateral representation of a motor vehicle, in which the four quadrants from FIG. 8 are indicated either in the area of a front or of a rear of the motor vehicle, in order to visualize the particular installation position.

DETAILED DESCRIPTION

[0101] Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.

[0102] In FIG. 1, a hybrid drive train 10 for a motor vehicle, in particular a passenger car, is represented in diagrammatic form.

[0103] The hybrid drive train 10 includes an internal combustion engine 12, which is connected to an input element of a dual-clutch assembly 14. The dual-clutch assembly 14 is connected on the output side to a hybrid transmission arrangement 16. An output of the hybrid transmission arrangement 16 is connected to a power distribution unit 18, which is, for example, a mechanical differential for distributing the input power to two driven wheels 20L, 20R of the motor vehicle.

[0104] Moreover, the hybrid drive train 10 includes a control device 22 for controlling all components thereof.

[0105] The dual-clutch assembly 14 is arranged on a first axis A1, which is coaxial to a crankshaft of the internal combustion engine 12. The dual-clutch assembly 14 includes two friction clutches or one friction clutch and a non-synchronized dog clutch. In the present case, the dual-clutch assembly 14 includes two non-synchronized dog clutches, including a first clutch K1 and a second clutch K2. The two clutches K1, K2 have a shared input element EG, which is rotationally fixed to the crankshaft of the internal combustion engine 12. The first clutch K1 has a first output element AG1. The second clutch K2 has a second output element AG2. The output elements AG1, AG2 are arranged coaxially to each other.

[0106] The transmission arrangement 16 includes a first input shaft 24 and a second input shaft 26. The input shafts 24, 26 are arranged coaxially to each other and to the first axis A1. The first input shaft 24 is an inner shaft. The second input shaft 26 is a hollow shaft.

[0107] Moreover, the transmission arrangement 16 includes a countershaft 28, which is an output shaft 28 and is arranged coaxially to a second axis A2. The output shaft 28 is connected via an output gear set 30 to the power distribution unit 18, which is arranged coaxially to a third axis A3.

[0108] A parking interlock gear is fixed at the output shaft 28 or at an input element of the power distribution unit 18 in a rotationally fixed manner, by which the hybrid drive train 10 is immobilized. The associated parking lock device is not represented, for the sake of clarity.

[0109] The transmission arrangement 16 has a first sub-transmission 32 and a second sub-transmission 34. The sub-transmissions 32, 34 are arranged axially offset with respect to each other. The first sub-transmission 32 is arranged adjacent to a first axial end of the transmission arrangement 16. The second sub-transmission 34 is arranged adjacent to a second axial end of the transmission arrangement 16, wherein the second axial end is adjacent to the dual-clutch assembly 14. The sub-transmissions 32, 34 have a plurality of engageable gear sets, which, in the engaged condition, connect an input shaft and the output shaft 28 in each case.

[0110] The first sub-transmission 32 has a first gear set 36 for the first forward gear step 1 and a second gear set 38 for the third forward gear step 3. The second gear set 38 is arranged closer to the first axial end of the transmission arrangement 16 than the first gear set 36. A first gearshift clutch assembly 40 is arranged between the first gear set 36 and the second gear set 38 and, in fact, coaxially to the second axis A2. The first gearshift clutch assembly 40 includes a first gearshift clutch A for engaging the first gear set 36 and a second gearshift clutch C for engaging the second gear set 38. The two gearshift clutches A, C are alternately engageable and are non-synchronized dog clutches. The engagement of a gear set includes the rotationally fixed connection of an idler gear of the particular gear set to an associated shaft. In the present case, for example, the first gear set 36 is engaged, in that an idler gear of the first gear set 36, which is rotatably mounted at the output shaft 28, is rotationally fixed to the output shaft 28, in order to bring the first gear set 36 into the power flow in this way.

[0111] Moreover, the first sub-transmission 32 has a third gear set 42 for the forward gear step 5. The third gear set 42 is arranged closer to the second axial end of the transmission arrangement 16 than the first gear set 36.

[0112] The third gear set 42 is engageable by a gearshift clutch E and has an idler gear, which is rotatably mounted at the first input shaft 24.

[0113] The second sub-transmission 34 has a fourth gear set 48 for the second forward gear step 2 and a fifth gear set 50 for the fourth forward gear step 4. The fifth gear set 50 is arranged closer to the second axial end than the fourth gear set 48. A second gearshift clutch assembly 52 is arranged between the gear sets 48, 50 and, in fact, coaxially to the second axis A2. The second gearshift clutch assembly 52 has a gearshift clutch B for engaging the fourth gear set 48 and a gearshift clutch D for engaging the fifth gear set 50. The gearshift clutches B, D are accommodated in the second gearshift clutch assembly 52 in such a way that the gearshift clutches B, D are alternately actuatable.

[0114] Consequently, the transmission arrangement 16 has five gear set planes, namely, starting from the second axial end toward the first axial end, in the following order: gear set 50 for the fourth forward gear step 4, gear set 48 for the second forward gear step 2, gear set 42 for the fifth forward gear step 5, gear set 36 for the first forward gear step 1, and gear set 38 for the third forward gear step 3.

[0115] Moreover, the hybrid drive train 10 includes a first electric machine 56, which is arranged coaxially to a fourth axis A4. The first electric machine 56 has a first pinion 58, which is rotationally fixed to a rotor of the first electric machine 56 and is coaxial to the fourth axis A4. The first pinion, which is also referred to as the first machine pinion, is connected to a gear-step gear set of the first sub-transmission 32, in the present case to the second gear set 38 for the third forward gear step 3, via a first intermediate gear 59, which is rotatably mounted at an axle (not described in greater detail). More precisely, the first pinion 58 meshes with the first intermediate gear 59, and the first intermediate gear 59 meshes with a fixed gear of the second gear set 38, wherein the fixed gear is rotationally fixed to the first input shaft 24.

[0116] Moreover, the hybrid drive train 10 has a second electric machine 60, which is arranged axially parallel to the input shafts 24, 26 and, in fact, coaxially to a fifth axis A5. The second electric machine has a second pinion (second machine pinion) 62, which is arranged coaxially to the fifth axis A5. The second pinion 62 is connected to the second input shaft 26 via a gear-step gear set of the second sub-transmission 34. In the present case, the second pinion 62 is connected to the fifth gear set for the fourth forward gear step 4 via a second intermediate gear 63. More precisely, the second pinion 62 meshes with the second intermediate gear 63, which is rotatably mounted at an axle (not described in greater detail), and the second intermediate gear 63 meshes with a fixed gear of the fifth gear set 50, wherein the fixed gear is rotationally fixed to the second input shaft 26.

[0117] The five axes A1, A2, A3, A4, A5 are all aligned in parallel with each other.

[0118] The dual-clutch assembly 14 is arranged adjacent to the second axial end of the transmission arrangement 16, as mentioned above. The output gear set 30 is also arranged on the second axial side of the transmission arrangement 16 and is preferably axially aligned with the dual-clutch assembly 14 or is situated approximately in a plane therewith. The parking interlock gear P is fixed at the output shaft 28 between the output gear set 30 and the fifth gear set 50.

[0119] In the hybrid drive train 10, the electric machines 56, 60 are each connected to a gear-step gear set of the associated sub-transmission, which is associated with the highest gear step of that sub-transmission. Moreover, the electric machines 56, 60 are each connected via a gear-step gear set to the associated particular sub-transmission, which is preferably arranged adjacent to an axial end of the transmission arrangement. The gear sets are situated at opposite axial ends.

[0120] The electric machines 56, 60 are arranged in axial overlap with each other. Due to the connection via intermediate gears 59, 63, high ratios for the particular gear-step gear sets are established, and so relatively high-speed electric machines are utilized, which are compact.

[0121] The hybrid transmission arrangement in the present example embodiment has precisely five forward gear steps and does not have a reverse gear step. An operation in reverse is exclusively established by the hybrid drive train 10 when one of the electric machines 56 or 60 is driven in the opposite direction of rotation.

[0122] The transmission arrangement 16 has no winding-path gear steps. Each gear set 36, 38, 42, 48, 50 includes precisely one idler gear and one fixed gear, wherein the idler gears of the gear sets 36, 38, 48, 50 are rotatably mounted at the output shaft 28, and wherein the idler gear of the gear set 42 is rotatably mounted at the first input shaft 24.

[0123] Moreover, the hybrid drive train 10 includes a third clutch K3, which is also referred to as a bridge clutch.

[0124] The third clutch is utilized for connecting the first input shaft 24 and the second input shaft 26. The third clutch K3 is arranged adjacent to the fourth gear set 48 for the second forward gear step 2 and is accommodated, with the gearshift clutch E for the third gear set 42 for engaging the fifth forward gear step 5, in a third gearshift clutch assembly 66. The third clutch K3, just like the gearshift clutches A, B, C, D, E, is implemented as a non-synchronized dog clutch.

[0125] The third gearshift clutch assembly 66 is arranged coaxially to the first axis A1 and, in fact, between the gear sets 42, 48.

[0126] The dual-clutch assembly 14 and the three gearshift clutch assemblies 40, 52, 66 are actuatable by four actuating units S1, S2, S3, S4.

[0127] One actuating unit S1 is utilized for actuating the dual-clutch assembly 14, the actuating unit S1 also engages the first clutch K1, engages the second clutch K2, or establishes a neutral position.

[0128] In a corresponding way, the first gearshift clutch assembly 40 is actuated by a fourth actuating unit S4. By the fourth actuating unit S4, either the gearshift clutch A is engaged, or the gearshift clutch C is engaged, or a neutral position is established.

[0129] In a corresponding way, the second gearshift clutch assembly 52 is actuated by a third actuating unit S3, in order to either engage the clutch D, or engage the clutch B, or establish a neutral position.

[0130] Finally, the third gearshift clutch assembly 66 is engaged by a second actuating unit S2, in order to either engage the third clutch K3, or engage the clutch E, or establish a neutral position.

[0131] In FIG. 2, a further example embodiment of a hybrid drive train 10′ is represented, which generally corresponds to the drive train 10 from FIG. 1 with respect to the configuration and mode of operation. Identical elements are therefore indicated by identical reference characters.

[0132] It is apparent that input power from the internal combustion engine is guided either via the first clutch K1 to the first sub-transmission 32 or via the second clutch K2 to the second sub-transmission 34. Input power of the first electric machine 56 is supplied directly into the first sub-transmission 32 or, via the first clutch K1, toward the internal combustion engine 12 (for example, in order to start the internal combustion engine 12).

[0133] Input power of the second electric machine 60 is introduced directly into the second sub-transmission 34 or, via the second clutch K2, to the internal combustion engine 12, for example, in order to start the internal combustion engine 12.

[0134] Moreover, it is apparent that the first sub-transmission 32 and the second sub-transmission 34 are connectable to each other via a third clutch K3, and so, for example, when the first clutch K1 is engaged, internal combustion engine-generated power flows via the third clutch K3 to the second sub-transmission 34.

[0135] In this case, the first electric machine 56 is switched to idle, and so the first electric machine 56 rotates in a nearly loss-free manner, or is operated as a generator or as an electric motor.

[0136] In a corresponding way, when the second clutch K2 is engaged, power of the internal combustion engine 12 is directed to the first sub-transmission 32 when the third clutch K3 is engaged.

[0137] Moreover, a serial operation is possible when, for example, purely electric motor-generated input power from the first electric machine 56 is guided via the first sub-transmission 32 to the output shaft 28. In this case, when the first and third clutches K1, K3 are disengaged, the second clutch K2 is engaged, in order to utilize input power of the internal combustion engine 12 to drive the second electric machine 60, in order to allow the second electric machine 60 to operate as a generator, which charges a battery (not represented in greater detail) of the drive train 10′. It is understood that all gearshift clutches of the second sub-transmission 34 are disengaged in this case.

[0138] In FIG. 3, a further example embodiment of a hybrid drive train 10″ is represented, which generally corresponds to the drive train 10 from FIG. 1 with respect to configuration and mode of operation. Identical elements are therefore labeled with identical reference characters. In the following, essentially, the differences are explained.

[0139] It is apparent, on the one hand, that the gear sets for the third and fifth forward gear steps 3, 5 are interchanged in the first sub-transmission 32. Consequently, the second gear set 38″ for the third forward gear step 3 is arranged closer to the second axial end of the transmission arrangement 16 than the third gear set 42″ for the fifth forward gear step 5, which is arranged adjacent to the first axial end of the transmission arrangement 16.

[0140] As represented in FIG. 3, moreover, the first electric machine 56 and/or the second electric machine 60 do/does not necessarily need to be connected via a gear-step gear set to the particular associated input shaft 24, 26. Rather, it is also possible to fix a first gearwheel (first machine gearwheel) 70″ at the first output shaft 24, which is in engagement with the first pinion 58 directly or via a first intermediate gear 59.

[0141] In a corresponding way, a second gearwheel (second machine gearwheel) 72″ is fixed at the second output shaft 26, which is in engagement with the second pinion 62 directly or via a second intermediate gear 63.

[0142] Due to the first gearwheel 70″ and/or the second gearwheel 72″, one additional degree of freedom is implemented, which simplifies the implementation of the pre-ratio.

[0143] The first gearwheel 70″ is preferably situated in a plane with the first gearshift clutch assembly 40″, and so this implementation is possible in a length-neutral manner. In the same way, the second gearwheel 72″ is axially aligned with the second gearshift clutch assembly 52, and so the provision of the second gearwheel 72″ also does not result in a lengthening of the installation space.

[0144] In particular for the case in which the gearwheels 70″, 72″ are not provided, but rather a connection is to take place via the gear sets that are arranged at the axial ends of the transmission arrangement 16, the following advantage is achieved. This is the case because the first electric machine 56 is connected to the first input shaft 24 via the gear-step gear set 42″ that represents the highest ratio of the first sub-transmission 32, and so a larger ratio is implemented in the electric operation.

[0145] The latter-described example variant is considered to be particularly preferred.

[0146] The hybrid drive train 10″ from FIG. 3 also does not include a third clutch K3. The gearshift clutch assembly 66″ therefore exclusively includes, in the present case, the gearshift clutch C for engaging the second gear set 38″ for the third forward gear step 3.

[0147] In FIG. 4, an alternative example embodiment of a dual-clutch assembly 14′″ is shown, which is utilized in each of the above-described example drive trains alternatively to the dual-clutch assemblies 14 utilized there.

[0148] The dual-clutch assembly 14′″ includes a second clutch K2, which, similarly to the dual-clutch assembly 14, is an unsynchronized dog clutch and which is actuatable by an actuating unit S1.

[0149] Instead of the unsynchronized dog clutch K1, a first clutch K1′″ is provided in the dual-clutch assembly 14′″ in the form of a normally disengaged friction clutch, which is actuatable either by the same actuating unit S1 or by a separate actuating unit S1a and, in fact, independently of the actuating unit S1.

[0150] The first clutch K1′″ is a normally disengaged friction clutch and has the advantage that the first clutch K1′″ is also disengageable under load, for example, in the case of an emergency brake application. As a result, the internal combustion engine is also decoupleable in an emergency of this type.

[0151] The second clutch K2 is not utilized in this case (as will also be explained in the following) for establishing a power flow for forward gear steps of the transmission arrangement 16, but rather essentially for coupling the second electric machine 60 to the internal combustion engine 12.

[0152] Different operations, which are establishable with the example hybrid drive train 10 from FIGS. 1 and 2, are explained with reference to FIGS. 5-7. Comparable operations are usable with the hybrid drive train 10″ from FIG. 3 and/or in connection with the dual-clutch assembly 14″ from FIG. 4.

[0153] FIG. 5 shows a gearshift table of the shift elements K1, K2, K3, A, B, C, D, E in a purely internal combustion engine-driven operation or in a hybrid operation, in which input power is made available by the internal combustion engine and, optionally, by the electric motors.

[0154] In all forward gear steps V1, V2, V3, V4, V5 establishable in this operation, the first clutch K1 is continuously engaged and the second clutch K2 of the dual-clutch assembly 14 is continuously disengaged. In the first forward gear step V1, the gearshift clutch A is engaged and all other gearshift clutches B, C, D, E are disengaged. The third clutch K3 is also disengaged. Consequently, power flows from the internal combustion engine via the first clutch K1 and the first input shaft 24 to the first gear set 36 and, from there, via the gearshift clutch A to the output shaft 28.

[0155] It is understood that a driving start from a standstill generally takes place purely by electric motors 56, 60 until a speed is reached, at which the internal combustion engine 12 is connected via the first clutch K1, i.e., at a speed that corresponds to a rotational speed above the idling speed of the internal combustion engine 12. Consequently, a driving start from a standstill takes place, for example, via the first electric machine 56 and the first gear set 36 for the first forward gear step V1. As soon as a speed has been reached that corresponds to the speed of the internal combustion engine 12, the first clutch K1 is engaged. The first clutch K1 remains engaged during the entire internal combustion engine-driven operation.

[0156] During the changeover from the first forward gear step V1 into the second forward gear step V2, initially the gearshift clutch B for the second forward gear step V2 is preliminarily engaged. This takes place, if necessary, with a synchronization by the second electric machine 60.

[0157] Thereafter, the gearshift clutch A for the first forward gear step V1 is disengaged, wherein the tractive force is supported by the second electric machine 60 and the already engaged gear set 48 for the second forward gear step V2. Thereafter, the third clutch K3 is engaged, wherein the synchronization necessary therefor takes place, on the one hand, by a rotational-speed adaptation of the internal combustion engine 12, but also by appropriate synchronization measures of the second electric machine 16. In the second forward gear step V2, power consequently flows from the internal combustion engine 12 via the first clutch K1, the first input shaft 24, the engaged third clutch K3, the second input shaft 26, and the gear set 48 for the second forward gear step V2, which is engaged by the gearshift clutch B, to the output shaft 28.

[0158] During the changeover into the third forward gear step V3, the third clutch K3 is disengaged, the tractive force is supported via the second electric machine 60 and, thereafter, the connecting gear step V3 is engaged in the first sub-transmission 32 by engaging the gearshift clutch C. The necessary synchronization takes place by the first electric machine 56.

[0159] Thereafter, the load is supported by the first electric machine 56 and the gearshift clutch B of the second forward gear step V2 is disengaged.

[0160] The further gear changes from the third and fourth gear steps V3, V4 and from the fourth and fifth gear steps V4, V5 result in a corresponding way. In both of the even forward gear steps V2, V4, the third gearshift clutch K3 is engaged. The second clutch K2 is always disengaged and the first clutch K1 is always engaged.

[0161] In FIG. 6, a purely electric motor-driven operation by the first electric machine is represented. In a first electric gear step E1.1, only the gearshift clutch A for the first forward gear step 1 is engaged. In a second electric forward gear step E1.2, only the gearshift clutch C is engaged. In a third electric-motor gear step E1.3, the gearshift clutch E is engaged.

[0162] In a corresponding way, FIG. 7 shows a purely electric motor-driven operation by the second electric machine 60. In a first gear step E2.1, only the gearshift clutch B is engaged. In a second electric gear step E2.2, only the gearshift clutch D is engaged.

[0163] In the purely electric operation according to FIGS. 6 and 7, purely electric powershifts (i.e., gear changes between forward gear steps without or with reduced interruption of tractive force) are possible. Here, an electric motor-driven operation is established exclusively, for example, between the gear steps E1.1, E1.2, E1.3 or exclusively between the gear steps E2.1, E2.2, and a gear change takes place while the other electric machine maintains the tractive force.

[0164] During a gear change, for example, from the forward gear step E1.1 into the forward gear step E1.2, the gearshift clutch B is engaged in the second sub-transmission and, consequently, the second electric machine 60 maintains the tractive force during the gear change in the first sub-transmission 32.

[0165] In the purely internal combustion engine-driven operation or hybrid operation (i.e., for the case in which internal combustion engine-generated power and, optionally, electric motor-generated power are guided to the output shaft), it is advantageous that the third clutch K3 is utilized for connecting the second input shaft 26 to the first input shaft 24 and, consequently, always supplying internal combustion engine-generated power into the transmission arrangement 16 via the first input shaft 24. Consequently, the first electric machine 56 associated with the first sub-transmission 32 is always rotationally fixed to the internal combustion engine 12 during this operation. As a result, it is possible to establish load-point displacements at the internal combustion engine 12 and the first electric machine 56 provides assistance during the closed-loop control of the rotational speed when a synchronization process is to take place. In other words, since the first clutch K1 always remains engaged, the first electric machine 56 assists the internal combustion engine 12 during synchronization.

[0166] In order to integrate the third clutch K3, which is necessary therefor, into the transmission arrangement as efficiently as possible, the third clutch K3 is accommodated in the third gearshift clutch assembly 66. Since the third clutch K3 is therefore integrated with a gearshift clutch into a gearshift clutch assembly that is associated with that sub-transmission, the associated first clutch K1—of the dual-clutch assembly 14—of which is always engaged in the internal combustion engine-driven or hybrid operation, the internal combustion engine utilizes all gear steps of the transmission.

[0167] The second clutch K2 is engaged, however, when a so-called “serial operation” is established. Here, the first clutch K1 is disengaged. Via the first sub-transmission 32 and the first electric machine 56, a purely electric motor-driven operation is established in a gear step, for example, in the first forward gear step 1. The internal combustion engine 12 drives the second electric machine 60 via the engaged second clutch K2 and operates it as a generator, and so the power withdrawn from a vehicle battery by the first electric machine 56 in this purely electric operation is simultaneously resupplied, at least partially, via the second electric machine 60.

[0168] A serial operation of this type is also possible in reverse when travel takes place purely electrically by the second electric machine 60 and the internal combustion engine 12 drives the first electric machine 56. In the latter case, the first clutch K1 is engaged and the second clutch K2 is disengaged.

[0169] The serial operation is utilized, in particular, in a so-called “crawling mode,” in which the vehicle speed is lower than a minimum speed that is establishable by the internal combustion engine 12.

[0170] The sub-transmission 32 that is associated with the first clutch K1, which is always engaged in the internal combustion engine-driven mode, preferably also includes the highest forward gear step of the transmission arrangement 16. As a result, when the third clutch K3 is disengaged, the second electric machine 60 is practically decoupled, in order to avoid drag losses. In addition, the first electric machine 56 remains coupled, in order to supply the main power circuit with electrical energy (operation as a generator), or in order to establish a boost operation (operation as a motor).

[0171] During a gear shift from a forward gear step of the first sub-transmission 32 into a forward gear step of the second sub-transmission 34, the desired gear step is initially engaged in the second sub-transmission by engaging the associated gearshift clutch (D or B). This takes place with the aid of a synchronization by the second electric machine 60, wherein the second electric machine 60 switches over, in a load-free manner, into this target gear step in the second sub-transmission 34. Thereafter, the second electric machine 60 supports the tractive force during the gear shift via the already engaged target gear step. During the gear shift, initially the gearshift clutch of the first sub-transmission 32, which is associated with the starting or source gear step, disengages and, thereafter, the third clutch K3 is engaged, wherein the internal combustion engine 12 and the first electric machine 56 interact during the synchronization.

[0172] During a gear shift from the second sub-transmission 34 into a gear step of the first sub-transmission 32, the second electric machine 60 initially supports the tractive force in the source gear step or the actual gear during the gear shift. During the gear shift, the third clutch K3 is initially disengaged and one of the shift elements A, C, E engages, wherein the internal combustion engine 12 and the first electric machine 56 interact during the necessary synchronization. After the disengagement of the third clutch K3 and the load transfer on the first sub-transmission 32, the output gear step (actual gear step) in the second sub-transmission 34 is disengaged.

[0173] It is understood that a stationary charging also takes place with the hybrid drive train when the vehicle is at a standstill. For example, the first clutch K1 is engaged and input power of the internal combustion engine 12 is supplied via the first input shaft 24 into the first electric machine 56. The second clutch K2 remains disengaged and the gearshift clutches A, C, E of the first sub-transmission 32 also remain disengaged. Therefore, the first sub-transmission 32 remains in neutral. In this condition, as mentioned, a stationary charging takes place, but a start of the internal combustion engine 12 by the first electric machine 56 also takes place.

[0174] In general, it is also conceivable to engage both clutches K1, K2 or to engage the first clutch K1 and the third clutch K3, in order to allow a charging process to take place by the first electric machine 56 and also by the second electric machine 60. In this case, the internal combustion engine 12 drives both electric machines and the electric machines 56, 60 both operate as generators, in order to charge a vehicle battery.

[0175] In the hybrid drive train 10″ from FIG. 3, the electric motor-driven operations are established precisely in the same way as described in FIGS. 6 and 7.

[0176] With regard to the internal combustion engine-driven operation and with regard to the hybrid operation, however, due to the absence of the third clutch K3 in the hybrid drive train 10″, a switch generally takes place back and forth between the first clutches K1, K2, in order to switch the power flow from one sub-transmission onto the other sub-transmission when a changeover is to take place from one gear step into a directly following connecting gear step. The first clutches K1, K2 are dog clutches in this case, or are friction clutches or formed by a dual-clutch assembly 14′″, as shown in FIG. 4.

[0177] In FIG. 8, an axial view of a drive train 10 is represented, which generally corresponds to the drive trains 10, 10″ from FIG. 1 or FIG. 3 with respect to configuration and mode of operation.

[0178] It is apparent that the first axis A1 of the input shafts 24, 26 is situated in a center of a coordinate system having four quadrants I, II, III, and IV.

[0179] Since the drive train 10, 10″ is generally installed transversely in the direction of travel of a motor vehicle, a preferred forward direction of travel at F is also represented in FIG. 8.

[0180] Of the four quadrants I-IV, a first quadrant I is situated above the input shaft arrangement 24, 26 and on a first longitudinal side (at the rear) of the input shaft arrangement 24, 26. A second quadrant II is situated below the input shaft arrangement and on the first longitudinal side. A third quadrant III is situated below the input shaft arrangement 24, 26 and is situated on a second longitudinal side (at the front) of the input shaft arrangement 24, 26. A fourth quadrant IV is situated above the input shaft arrangement and on the second longitudinal side of the input shaft arrangement.

[0181] The second axis A2 of the countershaft 28 is situated in the second quadrant II. The third axis A3 of the power distribution unit 18 is also situated in the second quadrant II. The second axis A2 is arranged closer to the third quadrant III than the third axis A3.

[0182] Actuating units S1-S4 are arranged in the third quadrant III.

[0183] The first electric machine 56 is completely arranged, with its fourth axis A4, in the first quadrant I. The second electric machine 60 is completely arranged, with its fifth axis A5, in the fourth quadrant IV.

[0184] The intermediate gear 59 is arranged completely in the first quadrant I. The intermediate gear 63 is arranged completely in the fourth quadrant IV.

[0185] The power distribution unit is arranged predominantly in the second quadrant II, although the power distribution unit can also extend into the first quadrant I.

[0186] The countershaft 28 with the gearwheels arranged thereon is arranged predominantly in the second quadrant II, although the countershaft 28 can also extend, with a few gearwheels, into the third quadrant III.

[0187] FIG. 9 shows how the hybrid drive train 10 is installable either in the front or in the rear of a motor vehicle 80, the longitudinal axis 82 of which is aligned with the preferred forward direction of travel F.

[0188] The longitudinal axis 82 of the motor vehicle 80 is preferably aligned in parallel to the axis of the above-described coordinate system that separates the quadrants I, IV situated at the top from the quadrants II, III situated at the bottom.

[0189] The third axis A3 is preferably situated coaxially to driven wheels.

[0190] In FIG. 9, the first axis A1 for a drive train 10 is arranged in the area of the front of the motor vehicle 80. In FIG. 9, alternatively, a first axis A1 for a drive train 10 is arranged in the area of a rear of the motor vehicle 80.

[0191] Modifications and variations can be made to the embodiments illustrated or described herein without departing from the scope and spirit of the invention as set forth in the appended claims. In the claims, reference characters corresponding to elements recited in the detailed description and the drawings may be recited. Such reference characters are enclosed within parentheses and are provided as an aid for reference to example embodiments described in the detailed description and the drawings. Such reference characters are provided for convenience only and have no effect on the scope of the claims. In particular, such reference characters are not intended to limit the claims to the particular example embodiments described in the detailed description and the drawings.

REFERENCE CHARACTERS

[0192] 10 hybrid drive train [0193] 12 internal combustion engine [0194] 14 dual-clutch assembly [0195] 16 hybrid transmission arrangement [0196] 18 power distribution unit [0197] 20 driven wheels [0198] 22 control device [0199] 24 first input shaft [0200] 26 second input shaft [0201] 28 output shaft [0202] 30 output gear set [0203] 32 first sub-transmission [0204] 34 second sub-transmission [0205] 36 gear set (1) [0206] 38 gear set (3) [0207] 40 first gearshift clutch assembly [0208] 42 gear set (5) [0209] 48 gear set (2) [0210] 50 gear set (4) [0211] 52 second gearshift clutch assembly [0212] 56 first electric machine [0213] 58 first pinion (first machine pinion) [0214] 59 first intermediate gear [0215] 60 second electric machine [0216] 62 second pinion (second machine pinion) [0217] 63 second intermediate gear [0218] 66 third gearshift clutch assembly [0219] 70 first gearwheel (first machine gearwheel) [0220] 72 second gearwheel (second machine gearwheel) [0221] 80 motor vehicle [0222] 82 longitudinal axis of motor vehicle [0223] A1-A5 axes [0224] A-E gearshift clutches for gear steps [0225] K1, K2 clutches of dual-clutch assembly [0226] EG input element [0227] AG1 first output element [0228] AG2 second output element [0229] K3 third clutch (bridge clutch) [0230] S1-S4 actuating units [0231] P parking interlock gear