Transmission Assembly, Motor Vehicle Powertrain, and Method for Operating Same

Abstract

A transmission arrangement (16) for a motor vehicle drive train (10) includes a first input shaft (24) connected or connectable to an internal combustion engine (12), a second input shaft (26) arranged coaxially to the first input shaft (24), an output shaft connected to the first input shaft (24) via a first plurality of engageable first gear-step gear sets (38, 42, 44) and connected to the second input shaft (26) via a second plurality of engageable second gear-step gear sets (36, 52), a first electric machine (56) connected to the second input shaft (26), a second electric machine (60) connected to the first input shaft (24), and a first clutch (K1) via which the first input shaft (24) and the second input shaft (26) are connectable to each other. The second gear-step gear sets include two alternately engageable gear-step gear sets (36, 52), via each of which an electric motor-driven operation is establishable by the first electric machine (56). The transmission arrangement (16) is configured such that an internal combustion engine-driven operation is establishable via one (36) of the two alternately engageable gear-step gear sets (36, 52) when the first clutch (K1) is engaged.

Claims

1.-15. (canceled)

16. A transmission arrangement (16) for a motor vehicle drive train (10), comprising: a first input shaft (24) connected or connectable to an internal combustion engine (12); a second input shaft (26) arranged coaxially to the first input shaft (24); an output shaft connected to the first input shaft (24) via a plurality of engageable first gear-step gear sets (38, 42, 44) and connected to the second input shaft (26) via a plurality of engageable second gear-step gear sets (36, 52); a first electric machine (56) connected to the second input shaft (26); a second electric machine (60) connected to the first input shaft (24); and a first clutch (K1) via which the first input shaft (24) and the second input shaft (26) are connectable to each other, wherein the second gear-step gear sets comprises two alternately engageable gear-step gear sets (36, 52), via each of which an electric motor-driven operation is establishable by the first electric machine (56), and wherein the transmission arrangement (16) is configured such that an internal combustion engine-driven operation is establishable via one (36) of the two alternately engageable gear-step gear sets (36, 52) when the first clutch (K1) is engaged.

17. The transmission arrangement of claim 16, wherein the first input shaft (24) is connected to the output shaft (28) via three of the engageable first gear-step gear sets (38, 42, 44).

18. The transmission arrangement of claim 16, wherein the two alternately engageable gear-step gear sets (36, 52) comprises a gear-step gear set (36) for a starting gear step, via which the internal combustion engine-driven operation is establishable.

19. The transmission arrangement of claim 16, wherein the other (52) of the two alternately engageable gear-step gear sets (36, 52) is associated with a second electric gear step (E1.2), and a ratio of the second electric gear step (E1.2) is less than a largest ratio of the first gear-step gear sets (38, 42, 44) and is greater than a smallest ratio of the first gear-step gear sets (38, 42, 44).

20. The transmission arrangement of claim 16, wherein the first clutch (K1) is arranged in an axial direction between the first gear-step gear sets (38, 42, 44) and the second gear-step gear sets (36, 52).

21. The transmission arrangement of claim 16, wherein the first clutch (K1) and a gearshift clutch (C; B) for engaging one (38; 42) of the first gear-step gear sets (38, 42, 44) form a first gearshift clutch assembly (40) actuatable by a single actuating unit (S1).

22. The transmission arrangement of claim 16, further comprising two gearshift clutches (B, D; C, D) that are configured for alternating engagement of two of the first gear-step gear sets (38, 44; 38, 44) and form a second gearshift clutch assembly (50).

23. The transmission arrangement of claim 16, further comprising two gearshift clutches (A, E) that are configured for alternating engagement of two of the second gear-step gear sets (36, 52) and form a third gearshift clutch assembly (54).

24. The transmission arrangement of claim 16, wherein the transmission arrangement comprises, axially one after the other starting from one axial end (74; 76): a gear set plane (El) for a second gear step (E2) usable by an electric motor; a gearshift clutch plane (E2) for a third gearshift clutch assembly (54); a gear set plane (E3) for a first gear step (1); a gearshift clutch plane (E4) for a first gearshift clutch assembly (40) that comprises the first clutch (K1); a gear set plane for a third gear step (3) or for a second gear step (2); a gear set plane (E6) for a second gear step (2) or a third gear step (3); a gearshift clutch plane (E7) for a second gearshift clutch assembly (50); and a gear set plane for a fourth gear step (4).

25. The transmission arrangement of claim 16, wherein the transmission arrangement includes an output gear set (30) at one axial end (74), by means of which the output shaft (28) is connected to a power distribution unit (18) for driven wheels (20L, 20R).

26. The transmission arrangement of claim 16, wherein: the first electric machine (56) is connected to the second input shaft (26) via one (52) of the second gear-step gear sets (36, 52); or the second electric machine (60) is connected to the first input shaft (24) via one (44) of the first gear-step gear sets (38, 42, 44); or both the first electric machine (56) is connected to the second input shaft (26) via the one (52) of the second gear-step gear sets (36, 52) and the second electric machine (60) is connected to the first input shaft (24) via the one (44) of the first gear-step gear sets (38, 42, 44).

27. The transmission arrangement of claim 26, wherein: one of the second gear-step gear sets (52), via which the first electric machine (56) is connected to the second input shaft (26), is arranged proximate a first axial end (74) of the transmission arrangement (16); or one of the first gear-step gear sets (44), via which the second electric machine (60) is connected to the first input shaft (24), is arranged proximate a second axial end (76) of the transmission arrangement (16); or both the one of the second gear-step gear sets (52), via which the first electric machine (56) is connected to the second input shaft (26), is arranged proximate the first axial end (74) of the transmission arrangement (16) and the one of the first gear-step gear sets (44), via which the second electric machine (60) is connected to the first input shaft (24), is arranged proximate the second axial end (76) of the transmission arrangement (16).

28. The transmission arrangement of claim 26, wherein: one of the second gear-step gear sets (52), via which the first electric machine (56) is connected to the second input shaft (26), is associated with a highest gear step (E1.2) establishable by the second gear-step gear sets (36, 52); or one of the first gear-step gear sets (44), via which the second electric machine (60) is connected to the first input shaft (24), is associated with a highest gear step (4) establishable by the first gear-step gear sets (38, 42, 44); or both the one of the second gear-step gear sets (52), via which the first electric machine (56) is connected to the second input shaft (26), is associated with the highest gear step (E1.2) establishable by the second gear-step gear sets (36, 52) and the one of the first gear-step gear sets (44), via which the second electric machine (60) is connected to the first input shaft (24), is associated with the highest gear step (4) establishable by the first gear-step gear sets (38, 42, 44).

29. A drive train for a motor vehicle, comprising: the internal combustion engine (12); and the transmission arrangement of claim 16, wherein the first input shaft (24) is rotationally fixed to the internal combustion engine, or the first input shaft (24) is connected to the internal combustion engine (12) via a separating clutch (K0).

30. A method for operating the drive train (10) of claim 29, comprising: starting from a purely electric operation or a hybrid operation via the one (36) of the two alternately engageable gear-step gear sets (36, 52), the first clutch (K1) engaged, the internal combustion engine (12) rotationally fixed to the first input shaft (24), and a gearshift clutch (A) associated with the one (36) of the two alternately engageable gear-step gear sets (36, 52); reducing load at the first clutch (K1) and building up load at the first electric machine (56); disengaging the first clutch (K1); reducing a rotational speed of the first input shaft (24) until a further gearshift clutch (B) associated with one of the first gear-step gear sets is synchronized; and engaging the further gearshift clutch (B).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0086] Exemplary embodiments of the invention are represented in the drawings and are explained in greater detail in the following description, wherein

[0087] FIG. 1 shows a schematic of an example embodiment of a drive train according to the invention with a transmission arrangement according to example aspects of the invention;

[0088] FIG. 2 shows a gearshift table for forward gear steps V1 through V4 in an internal combustion engine-driven operation or a hybrid operation by the drive train from FIG. 1;

[0089] FIG. 3 shows a gearshift table for two gear steps E1.1 and E1.2 in a purely electric motor-driven operation by the drive train from FIG. 1;

[0090] FIG. 4 shows a schematic of a further example embodiment of a drive train;

[0091] FIG. 5 shows a schematic of a further example embodiment of a drive train;

[0092] FIG. 6 shows a schematic of a further example embodiment of a drive train; and

[0093] FIG. 7 shows a schematic of a further example embodiment of a drive train.

DETAILED DESCRIPTION

[0094] 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.

[0095] In FIG. 1, a drive train in the form of a hybrid drive train is diagrammatically represented in diagrammatic form and is labeled, in general, with 10.

[0096] The drive train 10 includes an internal combustion engine 12. Moreover, the drive train 10 includes a clutch assembly 14, which is connected on the input side to the internal combustion engine 12. On the output side, the clutch assembly 14 is connected to a hybrid transmission arrangement 16. An output of the transmission arrangement 16 is connected to a power distribution unit 18, which can be formed, for example, by a mechanical differential. The power distribution unit 18 distributes input power to driven wheels 20L, 20R.

[0097] The drive train 10 is designed for installation transversely in a motor vehicle, for example, in the front or in the rear of a motor vehicle.

[0098] Moreover, the drive train 10 includes a control device 22, by which the shift elements of the drive train 10 and/or electric machines of the drive train 10 and/or an internal combustion engine of the drive train 10 are actuatable.

[0099] The transmission arrangement 16 includes a first input shaft 24 and a second input shaft 26. The first input shaft 24 is connected to an output element of the clutch assembly 14. The clutch assembly 14 includes, in the present case, a single clutch in the form of a separating clutch K0. The separating clutch K0 can be implemented as a dog clutch. The first input shaft 24 is situated on a first axis A1. The second input shaft 26 is arranged, as a hollow shaft, coaxially around the first input shaft 24.

[0100] The transmission arrangement 16 includes, furthermore, an output shaft 28, which is arranged axially parallel to the input shafts 24, 26 and, in fact, on a second axis A2.

[0101] The output shaft 28 is rotationally fixed to the power distribution unit 18 via an output gear set 30, wherein the power distribution unit 18 is situated on a third axis A3.

[0102] The transmission arrangement 16 includes a first sub-transmission 32, which is associated with the first input shaft 24. Moreover, the transmission arrangement 16 includes a second sub-transmission 34, which is associated with the second input shaft 26. The first sub-transmission 32 includes a plurality of engageable first gear-step gear sets. The second sub-transmission includes a second plurality of engageable second gear-step gear sets.

[0103] The second sub-transmission 34 includes a gear set 36, which is associated with a first forward gear step 1 for an internal combustion engine-driven operation and a gear step E1 (E1.1) for an electric motor-driven operation. The first sub-transmission 32 includes a gear set 38, which is associated with a third forward gear step 3.

[0104] A first gearshift clutch assembly 40 is arranged between the gear sets 36, 38. The first gearshift clutch assembly 40 includes a first clutch K1, by which the first input shaft 24 and the second input shaft 26 are connectable to each other in a rotationally fixed manner. Moreover, the first gearshift clutch assembly 40 includes a gearshift clutch C, which is associated with the gear set 38 for the forward gear step 3. The first gearshift clutch assembly 40 is actuatable by a single actuating unit S1 and can control either the first clutch K1 or the gearshift clutch C or establish a neutral position.

[0105] The first sub-transmission 32, furthermore, includes a gear set 42 for a second forward gear step 2 and includes a gear set 44 for a fourth forward gear step 4.

[0106] Between the gear sets 42, 44, the transmission arrangement 16 includes a second gearshift clutch assembly 50, which is arranged coaxially to the second axis A2. The second gearshift clutch assembly 50 includes a gearshift clutch B, which is associated with the gear set 42, and a gearshift clutch D, which is associated with the gear set 44. The second gearshift clutch assembly 50 is actuatable by a single actuating unit S2, wherein either the gearshift clutch B or the gearshift clutch D can be engaged, or a neutral position can be established.

[0107] The second sub-transmission 34 includes, in addition to the gear set 36 for the forward gear step 1, a gear set 52, which is associated with a second electric gear step E2 (E1.2).

[0108] Moreover, the transmission arrangement 16 includes a third gearshift clutch assembly 54, which is arranged on the second axis A2 and includes a gearshift clutch E for the gear set 52 and a gearshift clutch A for the gear set 36. The third gearshift clutch assembly 54 is actuatable by a third actuating unit S3, and so either the gearshift clutch E for engaging the gear set 52 or the gearshift clutch A for engaging the gear set 36 is engaged. Moreover, a neutral position can be established therebetween.

[0109] A parking interlock gear P can be rotationally fixed at the output shaft 28, in order to be able to immobilize a vehicle equipped with the drive train 10. An associated parking lock device is not represented in FIG. 1 for the sake of clarity.

[0110] The gear set 52 is arranged in a gear set plane E1, which is axially adjacent to the clutch assembly 14. On the axially opposite side, the third gearshift clutch assembly 54 is arranged in a clutch plane E2. Next thereto, the gear set 36 is arranged in a gear set plane E3. Next thereto, the first gearshift clutch assembly 40 is arranged in a clutch plane E4. Next thereto, the gear set 38 is arranged in a gear set plane E5. Next thereto, the gear set 42 is arranged in a gear set plane E6. Next thereto, the second gearshift clutch assembly 50 is arranged in a clutch plane E7. The gear set 44 is arranged in a gear set plane E8, which is situated at an end of the transmission arrangement 16 opposite the clutch assembly 14.

[0111] The transmission arrangement 16 includes a first electric machine 56, which is arranged coaxially to a fourth axis A4. The first electric machine 56 includes a first pinion (first machine pinion) 58, which is connected to the gear set 52 via an intermediate gear 59 for rotational-speed adaptation. The first electric machine 56 is therefore rotationally fixed to the fixed gear of the gear set 52, wherein the fixed gear of the gear set 52 forms a first gearwheel 70.

[0112] The transmission arrangement 16 includes, furthermore, a second electric machine 60, which is arranged on a fifth axis A5. The second electric machine 60 includes a second pinion 62, which is in engagement with the gear set 44 via a second intermediate gear 63. More precisely, the second intermediate gear 63 is in engagement with a second gearwheel (second machine gearwheel) 72, which is formed by the fixed gear of the gear set 44 fixed at the first input shaft 24.

[0113] The first gearwheel 70 (first machine gearwheel) is a fixed gear of the gear set 52 fixed at the second input shaft 26.

[0114] The transmission arrangement 16 includes a first axial end 74 and a second axial end 76. The internal combustion engine 12 and the clutch assembly 14 are arranged in an area of the first axial end. Of all gear sets of the transmission arrangement 16, the gear set 52 is arranged closest to the first axial end 74. Of all gear sets, the gear set 44 of the first sub-transmission 32 is arranged closest to the second axial end.

[0115] The electric machines 56, 60 overlap in the axial direction and preferably extend between the axial ends 74, 76.

[0116] By the drive train 10, the following operations represented in FIGS. 2 and 3 are implementable.

[0117] According to the gearshift table from FIG. 2, four internal-combustion-engine gear steps V1 through V4 are establishable. In all of them, the separating clutch K0 of the clutch assembly 14 is engaged (X in FIG. 2). Moreover, in the first forward gear step V1, the first clutch K1 is engaged and the gearshift clutch A of the gear set 36 is engaged.

[0118] Consequently, input power of the internal combustion engine 12 flows via the engaged separating clutch K0 onto the first input shaft 24 and, from there, via the first clutch K1 onto the second input shaft 26. Due to the engaged gearshift clutch A, the power flows via the gear set 36 onto the output shaft 28 and, from there, toward the power distribution unit 18.

[0119] In order to establish the second forward gear step V2, the first clutch K1 and the gearshift clutch A are disengaged and the gearshift clutch B is engaged. In this case, input power flows from the internal combustion engine 12 via the separating clutch K0 and the first input shaft 24 into the gear set 42 and, from there, into the output shaft 28. The other forward gear steps V3 and V4 result in a corresponding way, wherein, here, only one gearshift clutch is engaged in each case, namely either the gearshift clutch C or the gearshift clutch D.

[0120] The gearshift clutch E is never engaged in the internal combustion engine-driven operation, and so an internal combustion engine-driven operation is establishable when the first clutch K1 is engaged only via the gear set 36 of the second sub-transmission 34, and not via the gear set 52 of the second sub-transmission 34.

[0121] The forward gear steps represented in FIG. 2 are also implementable in a hybrid operation, in which internal combustion engine-generated power and electric motor-generated power from the second electric machine 60 are delivered into the first input shaft. Here, the second electric machine 60 can also operate as a generator, if necessary.

[0122] Moreover, in parallel thereto, the first electric machine 56 can provide input power via the second sub-transmission 34. Provided that the first clutch K1 is disengaged, in the forward gear steps V2, V3, and V4.

[0123] In FIG. 3, a gearshift table for two electric-motor gear steps E1.1 and E1.2 is represented, in which electric motor-generated input power is provided predominantly by the first electric machine 56. The first electric machine 56 is preferably designed as a main prime mover, whereas the second electric machine 60 can have a lower power.

[0124] In the first electric gear step E1.1, only the gearshift clutch A is engaged. All other shift elements are disengaged. When the separating clutch K0 is disengaged, the internal combustion engine 12 cannot deliver any power into the first input shaft 24. The second electric machine 60 cannot provide any additional input power, either, when the gearshift clutches B, C, D are disengaged.

[0125] A second electric gear step E1.2 is established when only the gearshift clutch E is engaged.

[0126] In the electric gear steps E1.1 and E1.2, however, it is possible to establish a serial operation, in which the separating clutch K0 is engaged and the internal combustion engine 12 drives the second electric machine 60 as a generator, in order to charge a vehicle battery, from which the first electric machine 56 withdraws input power.

[0127] Moreover, it is possible in the two forward gear steps E1.1 and E1.2 to provide additional electric motor-generated input power from the second electric machine 60, provided that the separating clutch K0 is disengaged and one of the gearshift clutches B, C, D is engaged. The first clutch K1 always remains disengaged in this case.

[0128] As described at the outset, all gear changes can take place in such a way that a synchronization can take place in advance by one or both electric machine(s), and so the gearshift clutches A, B, C, D, E and the first clutch K1 can also be designed as dog clutches without separate synchronization.

[0129] Moreover, all gear changes are implementable as powershifts, wherein, during gear shifts in the first sub-transmission 32, for example, a support of tractive force takes place via the first electric machine 56. During gear shifts in the second sub-transmission 34, a support of tractive force can be provided by the internal combustion engine 12 and/or the second electric machine 60.

[0130] In the following FIGS. 4 through 7, further example embodiments of drive trains are represented, which generally correspond to the drive train 10 from FIG. 1 with regard to configuration and mode of operation. Identical elements are therefore labeled with identical reference characters. In the following, essentially, the differences are explained.

[0131] In the transmission arrangement 16′ of the drive train 10′ from FIG. 4, the axial arrangement of the two sub-transmissions 32′, 34′ is interchanged. The interchange is provided in such a way that a type of mirror imaging has taken place at the gearshift clutch plane E4. The gear set 52′ is now arranged closest to the second axial end 76. The gear set 44′ is now arranged closest to the first axial end 74.

[0132] The drive train 10″ represented in FIG. 5 is based on the drive train 10 from FIG. 1, wherein a clutch assembly 14 is not provided, in such a way that the internal combustion engine 12 is rotationally fixed to the first input shaft 24.

[0133] In the drive train 10″ from FIG. 5, all functions as in the case of the drive train 10 from FIG. 1 are implementable, except for the possibility of a purely electric operation by the second electric machine 60 or a purely electric powershift between the gear steps E1.1 and E1.2.

[0134] In the drive train 10′″ from FIG. 6, which is based on the drive train 10 from FIG. 1, the clutch assembly 14′″ now includes a friction clutch K0′″ instead of a dog clutch. The clutch K0′″ is generally not utilized for pulling away from rest in the case of the drive train 10′″ either, however, but rather is still utilized as a pure separating clutch, similarly to the separating clutch K0 of the drive train 10 from FIG. 1. In contrast, the friction clutch K0′″ can also disengage under load. Moreover, an engagement of the friction clutch K0′″ can also take place at a differential speed between the internal combustion engine 12 and the first input shaft 24.

[0135] FIG. 7 shows a further drive train 10.sup.IV, which is based on the drive train 10 from FIG. 1. In the drive train 10.sup.IV, the gear sets for the second and third gear steps 2 and 3 are interchanged in the transmission arrangement 16.sup.IV.

[0136] In this case, the gear set 42.sup.IV is arranged adjacent to the first gearshift clutch assembly 40.sup.IV, which, in this case, includes the first clutch K1 and the gearshift clutch B for the forward gear step 2.

[0137] On the other hand, the gear set 38.sup.IV for the forward gear step 3 is now arranged in the axial direction between the gear set 42.sup.IV and the second gearshift clutch assembly 50.sup.IV. The second gearshift clutch assembly 50.sup.IV of the first sub-transmission 32.sup.IV includes the gearshift clutch C for the third forward gear step 3 and the gearshift clutch D for the fourth forward gear step 4.

[0138] 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

[0139] 10 hybrid drive train [0140] 12 internal combustion engine [0141] 14 clutch assembly [0142] 16 hybrid transmission arrangement [0143] 18 power distribution unit [0144] 20 driven wheels [0145] 22 control device [0146] 24 first input shaft [0147] 26 second input shaft [0148] 28 output shaft [0149] 30 output gear set [0150] 32 first sub-transmission [0151] 34 second sub-transmission [0152] 36 gear set (1/E1) [0153] 38 gear set (3) [0154] 40 first gearshift clutch assembly [0155] 42 gear set (2) [0156] 44 gear set (4) [0157] 50 second gearshift clutch assembly [0158] 52 gear set (E2) [0159] 54 third gearshift clutch assembly [0160] 56 first electric machine [0161] 58 first pinion (first machine pinion) [0162] 59 first intermediate gear [0163] 60 second electric machine [0164] 62 second pinion (second machine pinion) [0165] 73 second intermediate gear [0166] 70 first gearwheel (first machine gearwheel) [0167] 72 second gearwheel (second machine gearwheel) [0168] 74 first axial end [0169] 76 second axial end [0170] A1-A5 axes [0171] A-E gearshift clutches for gear-step gear sets [0172] K0 separating clutch [0173] E1-E8 gear set and clutch planes [0174] S1-S4 actuating units [0175] P parking interlock gear