Transmission for a Motor Vehicle

Abstract

A transmission (G) for a motor vehicle includes an electric machine (EM), a first input shaft (GW1), a second input shaft (GW2), an output shaft (GWA), a planetary gear set (P1), a pre-ratio configured as a spur gear transmission (SRS), and at least four shift elements (A, B, C′, D). Different gears are selectable by selectively actuating the at least four shift elements (A, B, C′, D) and, in addition, in interaction with the electric machine (EM), different operating modes are implementable.

Claims

1-11: (canceled)

12. A transmission (G) for a motor vehicle, comprising an electric machine (EM); a first input shaft (GW1); a second input shaft (GW2); an output shaft (GWA); a planetary gear set (P1) with a first elements (E11), a second element (E21), and a third element (E31); a plurality of shift elements with a first shift element (A), a second shift element (B), a third shift element (C′), and a fourth shift element (D); and a pre-ratio configured as a spur gear transmission (SRS) with a plurality of spur gears (SR1, SR2, SR3), wherein the first element (E11) of the planetary gear set (P1) is fixable at a rotationally fixed component (GG) by the first shift element (A), wherein the first input shaft (GW1) is rotationally fixable to the first element of the first planetary gear set (P1) by the second shift element (B), wherein the first planetary gear set (P1) is interlockable by connecting two of first, second, and third elements (E11, E21, E31) in a rotationally fixed manner by the fourth shift element (D), wherein the second element (E21) of the first planetary gear set (P1) is rotationally fixed to the output shaft (GWA), wherein a rotor of the electric machine is connected to the second input shaft (GW2) via the pre-ratio configured as the spur gear transmission (SRS), wherein the second input shaft (GW2) is rotationally fixed to the third element (E31) of the planetary gear set (P1), and wherein the third shift element (C′) is configured for rotationally fixing the first input shaft (GW1) to the second input shaft (GW2).

13. The transmission (G) of claim 12, wherein selective engagement of the plurality of shift elements (A, B, C′, D) results in: a first gear (V1) between the first input shaft (GW1) and the output shaft (GWA) by actuating the first shift element (A) and the third shift element (C′); and a third gear (V3) between the first input shaft (GW1) and the output shaft (GWA) by actuating the third shift element (C′) and the fourth shift element (D).

14. The transmission (G) of claim 12, wherein selective engagement of the plurality of shift elements (A, B, C′, D) results in: a first gear (V1) between the first input shaft (GW1) and the output shaft (GWA) by actuating the first shift element (A) and the third shift element (C′); and a third gear (V3) between the first input shaft (GW1) and the output shaft (GWA) by actuating the second shift element (B) and the fourth shift element (D).

15. The transmission (G) of claim 12, wherein: a first gear (E1) results between the second input shaft (GW2) and the output shaft (GWA) by actuating the first shift element (A); and a second gear (E2) results between the second input shaft (GW2) and the output shaft (GWA) by actuating the fourth shift element (D).

16. The transmission (G) of claim 12, wherein an electrodynamic starting operation (EDA) is implementable by actuating the second shift element (B).

17. The transmission (G) of claim 12, wherein one or more of the plurality of shift elements (A, B, C′, D) is a form-locking shift element.

18. The transmission (G) of claim 12, wherein the planetary gear set (P1) is a minus planetary gear set, the first element (E11) is a sun gear, the second element (E21) is a planet carrier, and the third element (E31) is a ring gear.

19. The transmission (G) of claim 12, wherein the first shift element (A) and the fourth shift element (D) are combined as a first shift element pair (SP1) with an associated actuating element via which the first shift element (A) and the fourth shift element (D) are respectively actuatable from a neutral position.

20. The transmission (G) of claim 12, wherein the third shift element (C′) and the second shift element (B) are combined to form a second shift element pair (SP2) with an associated actuating element via which the third shift element (C′) and the second shift element (B) are respectively actuatable from a neutral position.

21. The transmission (G) of claim 12, wherein the rotor (R) of the electric machine (EM) is rotationally fixed to the second input shaft (GW2) or is connected to the second input shaft (GW2) via at least one gear stage.

22. A motor vehicle drive train for a hybrid or electric vehicle, comprising the transmission (G) of claim 12.

23. A method for operating the transmission (G) of claim 12, wherein only the third shift element (C) is engaged in order to implement a charging operation or a starting operation.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0063] Advantageous example embodiments of the invention, which are explained in the following, are represented in the drawings, in which:

[0064] FIG. 1 shows a diagrammatic view of a motor vehicle drive train;

[0065] FIG. 2 shows a diagrammatic view of a transmission of the type that can be utilized in the motor vehicle drive train from FIG. 1;

[0066] FIG. 3 shows a diagrammatic view of a transmission of the type that can be utilized in the motor vehicle drive train from FIG. 1;

[0067] FIG. 4 shows an exemplary gear shift matrix of the transmission from FIGS. 2 and 3;

[0068] FIG. 5 shows a diagrammatic view of a transmission of the type that can also be utilized in the motor vehicle drive train from FIG. 1;

[0069] FIG. 6 shows a diagrammatic view of a transmission of the type that can also be utilized in the motor vehicle drive train from FIG. 1;

[0070] FIG. 7 shows a diagrammatic view of a transmission of the type that can also be utilized in the motor vehicle drive train from FIG. 1; and

[0071] FIG. 8 shows an exemplary gear shift matrix of the transmission from FIGS. 5 through 7.

DETAILED DESCRIPTION

[0072] 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.

[0073] FIG. 1 shows a diagrammatic view of a motor vehicle drive train of a hybrid vehicle, wherein, in the motor vehicle drive train, an internal combustion engine VKM is connected to a transmission G via an intermediate torsional vibration damper TS. Connected downstream from the transmission G, on the output end thereof, is a differential gear AG, via which drive power is distributed to driving wheels DW of a drive axle of the motor vehicle. The transmission G and the torsional vibration damper TS are arranged in a common housing of the transmission G in this case, into which the differential gear can then also be integrated. The internal combustion engine VKM, the torsional vibration damper TS, the transmission G, and also the differential gear are aligned transversely to a direction of travel of the motor vehicle.

[0074] FIG. 2 shows a schematic of the transmission G according to a first example embodiment of the invention. As is apparent, the transmission G includes a gear set RS and an electric machine EM, which are both arranged in the housing of the transmission G. The gear set RS includes two planetary gear sets P1 and P2, wherein each of the planetary gear sets P1 and P2 includes a first element E11 and E12, respectively, a second element E21 and E22, respectively, and a third element E31 and E32, respectively. The first element E11 and E12 is formed by a sun gear of the planetary gear set P1 and P2, respectively, while the second element E21 and E22 of the planetary gear set P1 and P2, respectively, is present as a planet carrier, and the third element E31 and E32 of the planetary gear set P1 and P2, respectively, is present as a ring gear.

[0075] In the present case, the first planetary gear set P1 and the second planetary gear set P2 are each therefore present as a negative or minus planetary gear set. The particular planet carrier thereof guides at least one planet gear in a rotatably mounted manner; the planet gear is meshed with the particular radially internal sun gear as well as with the particular radially surrounding ring gear. It is particularly preferred, however, when multiple planet gears are provided in the case of the first and the second planetary gear set P1 and P2.

[0076] As is apparent in FIG. 2, the transmission G includes a first input shaft GW1, a second input shaft GW2, and an output shaft GWA, wherein the second input shaft GW2 is rotationally fixed to a rotor R of an electric machine EM. The transmission G also includes four shift elements in the form of a first shift element A, a second shift element B, a third shift element C, and a fourth shift element D. The shift elements A, B, C, and D are designed as form-locking shift elements and are preferably present as constant-mesh shift elements. The four shift elements A, B, C, and D are present as clutches.

[0077] The first element E11 of the first planetary gear set P1 is fixable by the first shift element A at a rotationally fixed component GG, which is the transmission housing of the transmission G or a portion of this transmission housing.

[0078] The first element E11 of the first planetary gear set P1 is rotationally fixable to the first input shaft GW1 by the second shift element B.

[0079] The first element E11 of the first planetary gear set P1 is rotationally fixable to the second element E21 of the first planetary gear set P1 by the fourth shift element D. If the first element E11 and the second element E21 are connected to each other, the first planetary gear set P1 is interlocked.

[0080] The second element E21 of the first planetary gear set P1 is rotationally fixed to the output shaft GWA and, thereby, forms the output of the transmission G.

[0081] The output is, for example, coupled to an axle differential. In order to change the rotational speed of the output shaft 2, a two-stage gear stage can be provided, in particular, which couples the output shaft GWA to the axle differential. The third element E31 of the first planetary gear set P1 is rotationally fixed to the second element E22 of the second planetary gear set P2.

[0082] The first element E12 of the second planetary gear set P2 is rotationally fixed to the second input shaft GW2. The first element E12 of the second planetary gear set P2 can be rotationally fixed to the first input shaft GW1 by the third shift element C. If the third shift element C is actuated, the two input shafts GW1, GW2 are connected to each other. The third element E32 of the second planetary gear set P2 is rotationally fixed at the rotationally fixed component GG.

[0083] The second input shaft GW2 is permanently connected to the rotor R1 of the electric machine EM, the stator S1 of which is permanently fixed at the rotationally fixed component GG.

[0084] The first input shaft GW1 as well as the output shaft GWA form a mounting interface GW1-A and GWA-A, respectively, wherein the mounting interface GW1-A in the motor vehicle drive train from FIG. 1 is utilized for a connection at the internal combustion engine VKM, while the transmission G is connected at the mounting interface GWA-A to the downstream differential gear AG. The mounting interface GW1-A of the first input shaft GW1 is formed at an axial end of the transmission G, while the mounting interface GWA-A of the output shaft GWA is situated in the area of the same axial end and, here, is aligned transversely to the mounting interface GW1-A of the first input shaft GW1. In addition, the first input shaft GW1, the second input shaft GW2, and the output shaft GWA are arranged coaxially to one another.

[0085] The planetary gear sets P1 and P2 are also situated coaxially to the input shafts GW1 and GW2 and the output shaft GWA, wherein the planetary gear sets P1 and P2 are arranged in the sequence first planetary gear set P1 and second planetary gear set P2 axially subsequent to the mounting interface GW1-A of the first input shaft GW1. Likewise, the electric machine EM is also located coaxially to the planetary gear sets P1, P2 and, thereby, also to the input shafts GW1 and GW2 and to the output shaft GWA, wherein the two planetary gear sets P1, P2 are arranged at least partially radially within the rotor R.

[0086] As is also apparent from FIG. 2, the second shift element B and the third shift element C are arranged axially between the first planetary gear set P1 and the second planetary gear set P2. The first shift element A and the fourth shift element D are situated axially on a side of the first planetary gear set P1 facing away from the second planetary gear set P2.

[0087] The shift elements A and D as well as the shift elements B and C are situated axially directly next to one another and are combined to form a shift element pair SP1 and SP2, respectively.

[0088] In FIG. 3, a variant of the example embodiment according to FIG. 2 is shown. In contrast to FIG. 2, the first element E12 of the second planetary gear set P2 is now fixed at the housing GG, whereas the third element E32 of the second planetary gear set P2 is rotationally fixed to the second input shaft. Due to the switch of the connections of the sun gear and the ring gear, the third shift element E32 is now arranged axially on a side of the second planetary gear set P2 facing away from the first planetary gear set P1. For the rest, the example variant according to FIG. 4 corresponds to the example design option according to FIG. 2, and therefore reference is made to the description thereof.

[0089] FIG. 4 shows an exemplary gear shift matrix for the transmissions G from FIGS. 2 and 3 in table form. As is apparent, a total of three gears 1 through 3, which differ with respect to the transmission ratio, can be implemented between the first input shaft GW1 and the output shaft GWA, wherein, in the columns of the gear shift matrix, an X indicates which of the shift elements A through D is actuated, i.e., engaged, in which of the gears 1 through 3.

[0090] As is apparent in FIG. 4, a first gear V1 can be implemented between the first input shaft GW1 and the output shaft GWA by actuating the first shift element A and the third shift element C. A second gear V2 can be implemented by actuating the shift elements C and D. A third gear V3 can be implemented by actuating the shift elements B and D.

[0091] The first gear can be selected purely electrically (E1) by actuating the first shift element A. The second gear can be selected purely electrically (E2) by actuating the fourth shift element D.

[0092] The gears V1 and V2 are hybrid. The gears E1, E2 are purely electric-motor gears. The gear V3 is a purely internal-combustion-engine gear. The ratio step between V1 and V2 corresponds to the ratio step between E1 and E2.

[0093] In addition, an electrodynamic starting operation (EDA) is possible when the second shift element B is actuated.

[0094] If only the third shift element C is actuated, charging in neutral (LiN) is possible. In this condition, the first input shaft GW1 and the second input shaft GW2 are connected to each other and are decoupled from the output.

[0095] A synchronization during the gear shifts can take place in each case via an appropriate closed-loop control of the upstream internal combustion engine VKM, and therefore the particular shift element to be disengaged is disengaged without load and the shift element to be subsequently engaged can be engaged without load.

[0096] FIG. 5 shows a schematic of a transmission G according to a further example embodiment of the invention, of the type which can also be utilized in the motor vehicle drive train in FIG. 1.

[0097] As is apparent, the transmission G includes a gear set RS and an electric machine EM, which are both arranged in the housing of the transmission G. The gear set RS includes two planetary gear sets P1 and P2, wherein each of the planetary gear sets P1 and P2 includes a first element E11 and E12, respectively, a second element E21 and E22, respectively, and a third element E31 and E32, respectively. The first element E11 and E12 is formed by a sun gear of the planetary gear set P1 and P2, respectively, while the second element E21 and E22 of the planetary gear set P1 and P2, respectively, is present as a planet carrier, and the third element E31 and E32 of the planetary gear set P1 and P2, respectively, is present as a ring gear.

[0098] In the present case, the first planetary gear set P1 and the second planetary gear set P2 are each therefore present as a negative minus planetary gear set. The particular planet carrier thereof guides at least one planet gear in a rotatably mounted manner; the planet gear is meshed with the particular radially internal sun gear as well as with the particular radially surrounding ring gear. It is particularly preferred, however, when multiple planet gears are provided in the case of the first and the second planetary gear set P1 and P2.

[0099] As is apparent in FIG. 5, the transmission G includes a first input shaft GW1, a second input shaft GW2, and an output shaft GWA, wherein the second input shaft GW2 is rotationally fixed to a rotor R of an electric machine EM. The transmission G also includes four shift elements in the form of a first shift element A, a second shift element B, a third shift element C′, and a fourth shift element D. The shift elements A, B, C′, and D are designed as form-locking shift elements and are preferably present as constant-mesh shift elements. The four shift elements A, B, C′, and D are present as clutches.

[0100] The first element E11 of the first planetary gear set P1 is fixable by the first shift element A at a rotationally fixed component GG, which is the transmission housing of the transmission G or a portion of this transmission housing. The first element E11 of the first planetary gear set P1 is also rotationally fixable to the first input shaft GW1 by the second shift element B. The first element E11 of the first planetary gear set P1 is also rotationally fixable to the second element E21 of the first planetary gear set P1 by the fourth shift element D. If the first element E11 and the second element E21 are connected to each other, the first planetary gear set P1 is interlocked.

[0101] The second element E21 of the first planetary gear set P1 is rotationally fixed to the output shaft GWA and, thereby, forms the output of the transmission G. The output is, for example, coupled to an axle differential. In order to change the rotational speed of the output shaft 2, a two-stage gear stage can be provided, for example, which couples the output shaft 2 to the axle differential. The third element E31 of the first planetary gear set P1 is rotationally fixed to the second element E22 of the second planetary gear set P2.

[0102] The first element E12 of the second planetary gear set P2 is rotationally fixed to the second input shaft GW2. The second element E22 of the second planetary gear set P2 can be rotationally fixed to the first input shaft GW1 by the third shift element C′. The shift element C′ is preferably designed as a dog clutch. If the third shift element C′ is actuated, the two input shafts are not connected to each other directly, but rather via the second planetary gear set. The third element E32 of the second planetary gear set P2 is fixed at the rotationally fixed component GG. The second planetary gear set operates, in other words, as a type of fixed ratio of the electric machine.

[0103] The second input shaft GW2 is permanently connected to the rotor R1 of the electric machine EM, the stator S1 of which is permanently fixed at the rotationally fixed component GG.

[0104] The first input shaft GW1 as well as the output shaft GWA form a mounting interface GW1-A and GWA-A, respectively, wherein the mounting interface GW1-A in the motor vehicle drive train from FIG. 1 is utilized for a connection at the internal combustion engine VKM, while the transmission G is connected at the mounting interface GWA-A to the downstream differential gear AG. The mounting interface GW1-A of the first input shaft GW1 is formed at an axial end of the transmission G, while the mounting interface GWA-A of the output shaft GWA is situated in the area of the same axial end and, here, is aligned transversely to the mounting interface GW1-A of the first input shaft GW1. In addition, the first input shaft GW1, the second input shaft GW2, and the output shaft GWA are arranged coaxially to one another.

[0105] The planetary gear sets P1 and P2 are also situated coaxially to the input shafts GW1 and GW2 and the output shaft GWA, wherein they are arranged in the sequence first planetary gear set P1 and second planetary gear set P2 axially subsequent to the mounting interface GW1-A of the first input shaft GW1. Likewise, the electric machine EM is also located coaxially to the planetary gear sets P1, P2 and, thereby, also to the input shafts GW1 and GW2 and to the output shaft GWA, wherein the two planetary gear sets P1, P2 are arranged at least partially radially within the rotor R.

[0106] As is also apparent from FIG. 5, the second shift element B and the third shift element C are arranged axially between the first planetary gear set P1 and the second planetary gear set P2. The first shift element A and the fourth shift element D are situated axially on a side of the first planetary gear set P1 facing away from the second planetary gear set P2.

[0107] The shift elements A and D as well as the shift elements B and C′ are situated axially directly next to one another and are combined to form a shift element pair SP1 and SP2, respectively.

[0108] The difference from the example embodiment according to FIG. 2, therefore, lies in the alternative arrangement of the third shift element C and C′. In the LiN (charging in neutral) mode, this advantageously results in a higher rotational speed level of the rotor R connected to the second input shaft GW2.

[0109] FIG. 6 shows a variant of the example embodiment according to FIG. 5. In contrast to FIG. 5, the first element E12 of the second planetary gear set P2 is now fixed at the housing GG, whereas the third element E32 of the second planetary gear set P2 is rotationally fixed to the second input shaft GW2. In other words, the example embodiments from FIGS. 5 and 6 differ only with respect to the pre-ratio of the electric machine EM by the second planetary gear set P2. The example embodiment according to FIG. 5 has a higher pre-ratio than the example embodiment according to FIG. 6. For the rest, the example variant according to FIG. 6 corresponds to the example design option according to FIG. 5, and therefore reference is made to the description thereof.

[0110] FIG. 7 shows a schematic of a transmission G according to a further example embodiment of the invention, of the type which can also be utilized in the motor vehicle drive train in FIG. 1.

[0111] As is apparent, the transmission G includes a gear set RS, a pre-ratio SRS configured as a spur gear transmission, and an electric machine EM, which are all arranged in the housing of the transmission G. The gear set RS includes a planetary gear set P1, wherein the planetary gear set P1 includes a first element E11, a second element E21, and a third element E31. The first element E11 is formed by a sun gear, while the second element E21 is present as a planet carrier and the third element E31 is present as a ring gear.

[0112] In the present case, the first planetary gear set P1 is therefore present as a negative or minus planetary gear set, the planet carrier of which guides at least one planet gear in a rotatably mounted manner. The at least one planet gear is meshed with the particular radially internal sun gear as well as with the particular radially surrounding ring gear. It is particularly preferred when multiple planet gears are present in the planetary gear set P1.

[0113] The transmission G includes a first input shaft GW1, a second input shaft GW2, and an output shaft GWA. The transmission G also includes four shift elements in the form of a first shift element A, a second shift element B, a third shift element C′, and a fourth shift element D. The shift elements A, B, C′, and D are designed as form-locking shift elements and are preferably present as constant-mesh shift elements. The four shift elements A, B, C′, and D are present as clutches.

[0114] The electric machine EM shown in FIG. 7 is not located coaxially to the particular gear set RS of the transmission G, but rather axially offset with respect thereto. A connection takes place via a spur gear stage SRS, which includes a first spur gear SR1, a second spur gear SR2, and a third spur gear SR3. The first spur gear SR1 is connected at the second input shaft GW2 in a rotationally fixed manner on the side of the particular gear set RS. The spur gear SR1 is then meshed with the rotatably mounted spur gear SR2. The second gear SR2 is meshed with the third spur gear SR3, which is located on an input shaft EW of the electric machine EM in a rotationally fixed manner, which establishes, within the electric machine EM, the connection to the rotor (not represented further in this case) of the electric machine EM.

[0115] The first element E11 of the first planetary gear set P1 is fixable by the first shift element A at a rotationally fixed component GG, which is the transmission housing of the transmission G or a portion of this transmission housing CG. The first element E11 of the first planetary gear set P1 is also rotationally fixable to the first input shaft GW1 by the second shift element B. The first element E11 of the first planetary gear set P1 is also rotationally fixable to the second element E21 of the first planetary gear set P1 by the fourth shift element D. If the first element E11 and the second element E21 are connected to each other, the first planetary gear set P1 is interlocked.

[0116] The second element E21 of the first planetary gear set P1 is rotationally fixed to the output shaft GWA and, thereby, forms the output of the transmission G. The output is, for example, coupled to an axle differential. In order to change the rotational speed of the output shaft 2, a two-stage gear stage can be provided, for example, which couples the output shaft 2 to the axle differential.

[0117] The third element E31 of the first planetary gear set P1 is, as mentioned above, rotationally fixed to the first spur gear SR1. Both elements E31, SR1 can be rotationally fixed to the first input shaft GW1 by the third shift element C′. If the third shift element C′ is actuated, the two input shafts GW1, GW2 are directly connected to each other.

[0118] The first input shaft GW1 as well as the output shaft GWA form a mounting interface GW1-A and GWA-A, respectively, wherein the mounting interface GW1-A in the motor vehicle drive train from FIG. 1 is utilized for a connection at the internal combustion engine VKM, while the transmission G is connected at the mounting interface GWA-A to the downstream differential gear. The mounting interface GW1-A of the first input shaft GW1 is formed at an axial end of the transmission G, while the mounting interface GWA-A of the output shaft GWA is situated in the area of the same axial end and, here, is aligned transversely to the mounting interface GW1-A of the first input shaft GW1. In addition, the first input shaft GW1 and the output shaft GWA are arranged coaxially to each other.

[0119] The planetary gear set P1 and the pre-ratio in the spur gear design SRS are situated coaxially to the input shaft GW1, GW2 and the output shaft GWA. The electric machine EM can be connected to the first planetary gear set P1, rather than via one or multiple spur gear(s), also via a chain or a belt.

[0120] As is also apparent from FIG. 7, the second shift element B and the third shift element C are arranged axially between the first planetary gear set P1 and the spur gear stage SRS. The first shift element A and the fourth shift element D are situated axially on a side of the first planetary gear set P1 facing away from the spur gear stage SRS. The shift elements A and D as well as the shift elements B and C′ are situated axially directly next to one another and are combined to form a shift element pair SP1 and SP2, respectively.

[0121] FIG. 8 shows an exemplary gear shift matrix for the transmissions G from FIGS. 5 and 6 in table form. As is apparent, a total of three gears 1 through 3, which differ with respect to the transmission ratio, can be implemented between the first input shaft GW1 and the output shaft GWA, wherein, in the columns of the gear shift matrix, an X indicates which of the shift elements A through D is actuated, i.e., engaged, in which of the gears 1 through 3.

[0122] As is apparent in FIG. 8, a first gear V1′ can be implemented between the first input shaft GW1 and the output shaft GWA by actuating the first shift element A and the third shift element C′. A third gear can be implemented in a first example variant V3.1 by actuating the shift elements C′ and D. A third gear can be implemented in a second example variant V3.2 by actuating the shift elements B and D.

[0123] Gear 3 is now implementable using two different shift logics, i.e., in two example variants.

[0124] The first gear can be selected purely electrically (E1) by actuating the first shift element A. The second gear can be selected purely electrically (E2) by actuating the fourth shift element D.

[0125] The gears V1′ and V3.1 are hybrid. The gears E1, E2 are purely electric-motor gears. The gear V3.2 is a purely internal-combustion-engine gear.

[0126] The first gear V1′ has a lower ratio than the first gear V1 of the example embodiments from FIGS. 2 and 3. The ratio step between V1′ and V3.1 and/or V3.2 corresponds to the ratio step between E1 and E2.

[0127] In addition, an electrodynamic starting operation (EDA) is possible when the second shift element B is actuated.

[0128] If only the third shift element C′ is actuated, charging in neutral (LiN) is possible, wherein, in contrast to the clutch assembly in FIGS. 2 and 3, the rotor has a higher rotational speed level.

[0129] A synchronization during the gear shifts can take place in each case via an appropriate closed-loop control of the upstream internal combustion engine VKM, and therefore the particular shift element to be disengaged is disengaged without load and the shift element to be subsequently engaged can be engaged without load.

[0130] By the example embodiments according to the invention, a transmission having a compact design and good efficiency can be implemented. The transmission can be actuated using only two actuators. Two purely electric gears signify a rather low torque demand, and so the electric machine can be small-dimensioned.

[0131] 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

[0132] G transmission [0133] RS gear set [0134] GG rotationally fixed component [0135] P1 first planetary gear set [0136] E11 first element of the first planetary gear set [0137] E21 second element of the first planetary gear set [0138] E31 third element of the first planetary gear set [0139] P2 second planetary gear set [0140] E12 first element of the second planetary gear set [0141] E22 second element of the second planetary gear set [0142] E32 third element of the second planetary gear set [0143] A first shift element [0144] B second shift element [0145] C, C′ third shift element [0146] D fourth shift element [0147] SP1 shift element pair [0148] SP2 shift element pair [0149] V1 first gear [0150] V2 second gear [0151] V3 third gear [0152] V3.1 third gear, first variant [0153] V3.2 third gear, second variant [0154] E1 first gear, electric [0155] E2 second gear, electric [0156] GW1 first input shaft [0157] GW1-A mounting interface [0158] GW2 second input shaft [0159] GWA output shaft [0160] GWA-A mounting interface [0161] AN connection shaft [0162] EM electric machine [0163] S stator [0164] R rotor [0165] SRS spur gear stage [0166] SR1 spur gear [0167] SR2 spur gear [0168] SR3 spur gear [0169] HO ring gear [0170] VKM internal combustion engine [0171] DW driving wheels