Hybrid Transmission for a Motor Vehicle

Abstract

A hybrid transmission (10) for a motor vehicle with an internal combustion engine (VM) and an electric prime mover (EM1) is provided. The hybrid transmission (10) includes a first transmission input shaft (14) for a first sub-transmission, a second transmission input shaft (16) for a second sub-transmission, at least one countershaft (18), multiple gear change devices (A-F) for engaging gear steps (E1, E2, 1, 2, 3, 4), and idler gears and fixed gears arranged in multiple gear set planes for forming the gear steps. A portion of the gear steps are engageable for the internal combustion engine, and a portion of the gear steps are engageable for the electric prime mover. At least one of the gear steps is engageable for the internal combustion engine and for the electric prime mover regardless of the gear step engaged for the particular other machine.

Claims

1-12. (canceled)

13. A hybrid transmission (10) for a motor vehicle with an internal combustion engine (VM) and an electric prime mover (EM1), the hybrid transmission (10) comprising: a first transmission input shaft (14) for a first sub-transmission; a second transmission input shaft (16) for a second sub-transmission; at least one countershaft (18); a plurality of gear change devices (A-F) for engaging a plurality of gear steps (E1, E2, 1, 2, 3, 4); and a plurality of idler gears (28, 30, 20, 22) and a plurality of fixed gears (32, 34, 24, 26) arranged in multiple gear set planes for forming the gear steps, wherein a portion of the gear steps are engageable for the internal combustion engine (VM), and a portion of the gear steps are engageable for the electric prime mover (EM1), and wherein at least one of the gear steps is engageable for both the internal combustion engine (VM) and the electric prime mover (EM1) regardless of the gear step engaged for the respective one of the internal combustion engine (VM) and the electric prime mover (EM1).

14. The hybrid transmission (10) of claim 13, wherein: the plurality of gear steps is four gear steps; the first and second gear steps (E1, E2) of the four gear steps are engageable for the electric prime mover (EM1); the second gear step (E2, 2) is engageable for the internal combustion engine (VM) and for the electric prime mover (EM1); the first, second, second, third, and fourth gear steps (1, 2, 3, 4) of the four gear steps are engageable for the internal combustion engine (VM) when the first gear step (E1) is engaged for the electric prime mover (EMI); and the second, third, and fourth gear steps of the four gear steps (2, 3, 4) are engageable for the internal combustion engine (VM) when the second gear step (E2) is engaged for the electric prime mover (EMI).

15. The hybrid transmission (10) of claim 13, wherein: the first transmission input shaft (14) and the second transmission input shaft (16) are arranged coaxially; and one of the plurality of gear change devices (A-F), in one shift position, drivingly connects the first and second transmission input shafts (14, 16) to each other.

16. The hybrid transmission (10) of claim 13, wherein the gear change devices (A-F) are double shift elements (AB, CD, EF), each of which is actuatable by a double-acting actuator; and the two of the plurality of gear steps engageable for the electric prime mover (EM1) are engageable by one of the double shift elements (AB).

17. The hybrid transmission (10) of claim 13, wherein an idler gear (30) of the plurality of idler gears (28, 30, 20, 22) of the gear set that forms the second gear step (E2, 2) is arranged at a hollow shaft.

18. The hybrid transmission (10) of claim 13, wherein: the electric prime mover (E1) is actuatable as an integrated starter generator for starting the internal combustion engine (VM); or the electric prime mover (E1) is actuatable as a charging generator for charging an energy accumulator or for supplying a main power circuit; or the electric prime mover (E1) is actuatable as both the integrated starter generator for starting the internal combustion engine (VM) and the charging generator for charging the energy accumulator or for supplying the main power circuit.

19. The hybrid transmission (10) of claim 13, wherein the internal combustion engine (VM) is directly operatively connected to the first transmission input shaft (14), and the electric prime mover (EM1) is actuatable as a starting component for starting the motor vehicle.

20. The hybrid transmission (10) of claim 13, wherein the second transmission input shaft (16) is a hollow shaft and at least partially encompasses the first transmission input shaft (14).

21. A drive train (12), comprising: the internal combustion engine (VM) for providing input power; the electric prime mover (EM1) for providing input power; and the hybrid transmission (10) of claim 13.

22. The drive train of claim 21, wherein: the electric prime mover (EM1) is at least partially actuatable as a supporting force during gear changes of the internal combustion engine (VM); or the internal combustion engine is at least partially actuatable as a supporting force during gear changes of the electric prime mover; or both the electric prime mover (EM1) is at least partially actuatable as the supporting force during gear changes of the internal combustion engine (VM) and the internal combustion engine is at least partially actuatable as the supporting force during gear changes of the electric prime mover.

23. The drive train (12) of claim 21, further comprising a second electric prime mover (EM2) connected in series with the internal combustion engine (VM) on the first transmission input shaft (14).

24. A motor vehicle, comprising: an energy accumulator for storing energy for supplying electric prime movers and vehicle electronics; a main power circuit for transmitting energy from the energy accumulator and/or from an electric prime mover operated as a charging generator; and the drive train (12) of claim 21.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Example aspects of the invention are described and explained in greater detail in the following with reference to a few selected exemplary embodiments in conjunction with the attached drawings, in which:

[0041] FIG. 1 shows a schematic of an embodiment of a hybrid transmission according to the invention in a first example variant;

[0042] FIG. 2 shows a schematic of a gear shift matrix of the hybrid transmission according to example aspects of the invention;

[0043] FIG. 3 shows a schematic of an embodiment of a hybrid transmission according to the invention in a second example variant;

[0044] FIG. 4 shows a schematic of an embodiment of a hybrid transmission according to the invention in a third example variant;

[0045] FIG. 5 shows a schematic of an embodiment of a hybrid transmission according to the invention in a fourth example variant;

[0046] FIG. 6 shows a schematic of an embodiment of a hybrid transmission according to the invention in a fifth example variant;

[0047] FIG. 7 shows a schematic of an embodiment of a hybrid transmission according to the invention in a sixth example variant;

[0048] FIG. 8 shows a schematic of an embodiment of a hybrid transmission according to the invention in a seventh example variant;

[0049] FIG. 9 shows a schematic of an embodiment of a hybrid transmission according to the invention in an eighth example variant;

[0050] FIG. 10 shows a schematic of an embodiment of a hybrid transmission according to the invention in a ninth example variant; and

[0051] FIG. 11 shows a schematic of an embodiment of a hybrid transmission according to the invention in a tenth example variant.

DETAILED DESCRIPTION

[0052] 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.

[0053] FIG. 1 diagrammatically shows an example embodiment of a hybrid transmission 10 in a drive train 12 with a first transmission input shaft 14, a second transmission input shaft 16, and a countershaft 18. The first transmission input shaft 14 is designed as a solid shaft and is drivingly connected to an internal combustion engine VM. The second transmission input shaft 16 is designed as a hollow shaft and is drivingly connected to an electric prime mover EM1. Arranged at the first transmission input shaft 14 are two idler gears 20, 22 designed as spur gears, which mesh with two fixed gears 24, 26 of the countershaft 18, which are also designed as spur gears, in order to form the spur gear stages i3 and i4. Arranged at the second transmission input shaft 16 are two idler gears 28, 30 designed as spur gears, which mesh with two fixed gears 32, 34 of the countershaft 18, which are also designed as spur gears, in order to form the spur gear stages i1 and i2. The countershaft 18 is drivingly connected, via a gearwheel pair having an output spur gear stage iab, to a differential 36, which directs input power to driving wheels (not shown here).

[0054] The first transmission input shaft 14 and the second transmission input shaft 16 are arranged coaxially to each other and parallel to the countershaft 18. The second transmission input shaft 16 encompasses, at least partially or in sections, the first transmission input shaft 14. The idler gears 28, 30 of the second transmission input shaft 16 are rotationally fixable to the second transmission input shaft 16 by the shift elements A, B. The idler gears 20, 22 of the first transmission input shaft 14 are rotationally fixable to the first transmission input shaft 14 by the shift elements E, F. The first transmission input shaft 14 is drivingly connectable to the second transmission input shaft 16 by a shift element D. The idler gear 30 forming, with the fixed gear 34, the spur gear stage i2, is drivingly connectable to the first transmission input shaft 14 by a shift element C. The shift elements A, B, C, D, E, F are designed as double shift elements AB, CD, EF, which are arranged at the two transmission input shafts 14, 16. The first transmission input shaft 14 and the second transmission input shaft 16 form, with the countershaft 18, a sub-transmission in each case.

[0055] FIG. 2 shows a gear shift matrix 38 of the hybrid transmission from FIG. 1 and of the following example embodiments of hybrid transmissions. Thirteen shift conditions, overall, are represented in the first column. In the second column, the gear steps of the internal combustion engine VM designated as internal-combustion-engine gear steps are represented, wherein “0” means that no input power from the internal combustion engine VM is transmitted to the countershaft 18. In the third column, the gear steps of the electric prime mover EM1 designated as electric-machine gear steps are represented, wherein “0” means that no input power from the electric prime mover EM1 is transmitted to the countershaft 18. In the fourth to ninth columns, the shift conditions of the shift elements A, B, C, D, E, F are shown, wherein “X” means that the shift element is engaged, i.e., the idler gear associated therewith is rotationally fixed to the shaft associated therewith. The shift element A is associated with the idler gear 28, which, with a fixed gear 32, forms the first spur gear stage i1. The shift element B is associated with the idler gear 30, which, with a fixed gear 34, forms the second spur gear stage i2. The shift element C is also associated with the idler gear 30, which, with a fixed gear 34, forms the second spur gear stage i2. The shift element D drivingly connects the first transmission input shaft 14 and the second transmission input shaft 16. The shift element E is associated with the idler gear 20, which, with a fixed gear 24, forms the third spur gear stage i3. The shift element F is associated with the idler gear 22, which, with a fixed gear 26, forms the fourth spur gear stage i4.

[0056] In a purely electric operation, the electric prime mover can transmit input power by the electric-machine gear steps E1 and E2, i.e., the spur gear stages i1 and i2, for power transmission. These two electric-machine gear steps can be engaged by the double shift element AB. The other shift elements, C, D, E; F, are in a neutral position, i.e., do not connect the idler gear associated therewith to the shaft associated with the shift element.

[0057] In a hybrid operation, the electric prime mover EM1 transmits input power by the electric-machine gear steps E1 or E2. Additionally, the internal combustion engine VM transmits input power by the internal-combustion-engine gear steps 1, 2, 3, 4 formed by the spur gear stages i1, i2, i3, i4. The vehicle is in an operating condition, in which input power is provided by the electric prime mover EM1 as well as by the internal combustion engine VM. The internal-combustion-engine gear steps 3 and 4 are engaged by the double shift element EF. The internal-combustion-engine gear steps 1 and 2 are engaged by the double shift element CD. The internal-combustion-engine gear steps 1 and 2 are established by the same gearwheel pairs or spur gear stages i1, i2 as the electric-machine gear steps E1 and E2. In order to engage the first internal-combustion-engine gear step, the two transmission input shafts 14, 16 are drivingly connected to each other by the shift element D, and the shift element A is engaged. In order to engage the second internal-combustion-engine gear step, the shift element C is engaged. During the hybrid operation, all internal-combustion-engine gear steps 1, 2, 3, 4 are engageable when the electric prime mover utilizes the first electric-machine gear step E1. The internal-combustion-engine gear steps 2, 3, 4 are engageable when the electric prime mover utilizes the second electric-machine gear step E2.

[0058] In a purely internal combustion engine-driven operation, the internal combustion engine VM can transmit input power by the internal-combustion-engine gear steps 2, 3, 4. The electric prime mover EM1 is not operated in this case. The internal-combustion-engine gear steps 3 and 4 are engaged by the double shift element EF. The internal-combustion-engine gear step 2 is engaged by the shift element C. The shift element D drivingly connects the first transmission input shaft 14 and the second transmission input shaft 16, in order to operate the electric prime mover EM1 as a generator and charge an energy accumulator, for example, while the vehicle is at rest with the internal combustion engine VM running. Moreover, as a result, the electric prime mover EM1 can be utilized as a starter for the internal combustion engine VM.

[0059] In the example embodiment shown in FIG. 1, the shift element A rotationally fixes the idler gear 28 to the second transmission input shaft 16. The shift element B rotationally fixes the idler gear 30 to the second transmission input shaft 16. The shift element C rotationally fixes the idler gear 30 to the first transmission input shaft 14. The shift element E connects the idler gear 20 to the first transmission input shaft 14. The shift element F connects the idler gear 22 to the first transmission input shaft 14.

[0060] In the following, identical reference characters refer to identical features and are not explained in greater detail. Preferably, only the differences in the example variants of hybrid transmissions are discussed.

[0061] In FIG. 3, a second example variant of a hybrid transmission 10 according to the invention is shown in a drive train 12. In contrast to the hybrid transmission shown in FIG. 1, the second transmission input shaft 16 is also designed as a solid shaft. In addition, the electric prime mover EM1 is arranged at the end of the hybrid transmission 10 opposite the internal combustion engine VM. The gearwheel pairs for forming the internal-combustion-engine gear steps 3, 4 are arranged adjacent to the internal combustion engine VM. The transmission input shafts 14, 16 are mounted one inside the other in a center of the hybrid transmission 10.

[0062] In FIG. 4, a third example variant of a hybrid transmission 10 according to the invention is shown in a drive train 12. In contrast to the hybrid transmission 10 shown in FIG. 1, the shift element A is located at the countershaft 18. As a result, the gearwheel pair 28, 32 forming the first spur gear stage i1 has one fewer hollow shaft. The double shift element AB is less easily representable. For example, a shared shift rail having two separate shift forks can be utilized.

[0063] In FIG. 5, a fourth example variant of a hybrid transmission 10 according to the invention is shown in a drive train 12. In contrast to the hybrid transmission 10 shown in FIG. 4, the shift element D is located at a transmission input, i.e., adjacent to the internal combustion engine VM. As a result, the gearwheel pair 30, 34 forming the second spur gear stage i2 has one fewer hollow shaft. The double shift element CD is less easily representable. For example, a shared shift rail having two separate shift forks can be utilized.

[0064] In FIG. 6, a fifth example variant of a hybrid transmission 10 according to the invention is shown in a drive train 12. In contrast to the hybrid transmission 10 shown in FIG. 5, the double shift element EF is arranged on the countershaft 18.

[0065] In FIG. 7, a sixth example variant of a hybrid transmission 10 according to the invention is shown in a drive train 12. In contrast to the hybrid transmission 10 shown in FIG. 6, one further countershaft 40 is provided. The further countershaft 40 is drivingly connected to the differential 36 via a gearwheel pair of a further output spur gear stage iab2. The idler gear 22 is arranged on the further countershaft 40, in order to design the hybrid transmission 10 with a shorter axial installation length. The double shift element EF is less easily representable. For example, a shared shift rail having two separate shift forks can be utilized. The spur gear stages i3 and i4 utilize a shared fixed gear 42 on the first transmission input shaft 14. The fact that spur gear stage i4 represents a “longer” (i.e., less small) spur gear stage than spur gear stage i3 can be achieved in that the idler gear 22 of spur gear stage i4 is selected to be smaller than the idler gear 20 of spur gear stage i3. Alternatively or in combination therewith, the further output spur gear stage iab2 can be designed to be “longer” than the output spur gear stage iab. The unoccupied axial installation space on the further countershaft 40 can be utilized, for example, for a parking lock.

[0066] In FIG. 8, a seventh example variant of a hybrid transmission 10 according to the invention is shown in a drive train 12. In contrast to the hybrid transmission 10 shown in FIG. 7, the shift element F is arranged on the side of the idler gear 22 facing the internal combustion engine VM. The hybrid transmission is axially shorter.

[0067] In FIG. 9, an eighth example variant of a hybrid transmission 10 according to the invention is shown in a drive train 12. In contrast to the hybrid transmission 10 shown in FIG. 6, a second electric prime mover EM2 is provided. The second electric prime mover EM2 is connected to the first transmission input shaft 14 by a spur gear stage. It is understood that a connection by a flexible traction drive mechanism can also be provided. In addition, a separating clutch K0 is provided between the first transmission input shaft 14 and the internal combustion engine VM. As a result, the second electric prime mover EM2 can be utilized, instead of the internal combustion engine VM, in a purely electric operation when the internal combustion engine VM is separated from the first transmission input shaft 14. The second electric prime mover EM2 can take over the functions of the internal combustion engine VM, such as, for example, applying supporting force during gear changes of the first electric machine EM1.

[0068] The second electric prime mover EM2 can be utilized in a hybrid operation for assisting the internal combustion engine VM. The clutch K0 is designed to be form-locking. It is understood that a friction-locking clutch can also be utilized, in order, for example, to allow for a purely internal combustion engine-driven starting operation. If the clutch K0 is engaged, i.e., the first transmission input shaft 14 is drivingly connected to the internal combustion engine VM, the following functions are possible: a start of the internal combustion engine VM from a purely electric operation; the supply of a main power circuit of a hybrid vehicle by the internal combustion engine VM, which drives the second electric prime mover, which acts as a generator; a serial driving operation forward and also in reverse. Here, the internal combustion engine VM drives the second electric prime mover as a generator. The electrical energy generated by the second electric machine EM2 (generator) is then supplied to the electric prime mover EM1, and so the electric prime mover EM1 can provide input power. The electric prime mover EM1 can be operated in both directions of rotation, in order to allow for forward travel and travel in reverse. It is understood that the clutch K0 can also be omitted, depending on which functions are to be represented with the hybrid transmission 10.

[0069] In FIG. 10, a ninth example variant of a hybrid transmission 10 according to the invention is shown in a drive train 12. In contrast to the hybrid transmission 10 shown in FIG. 9, the two electric prime movers EM1, EM2 are each connected to the hybrid transmission 10 by a chain drive. Moreover, the clutch K0 is designed as a friction-locking clutch, in order to allow for the following functions: disengage the clutch K0 under load, such as, for example, during an emergency brake application; a purely internal combustion engine-driven starting operation; entrainment of the internal combustion engine VM into motion during travel, in order to start the internal combustion engine VM; flywheel start of the internal combustion engine VM by the second electric prime mover EM2. Moreover, an engagement of the clutch K0 is simplified, since a synchronization can be omitted or, preferably, only a small synchronization is necessary. It is understood that, in this example embodiment, a connection of at least one of the two electric machines EM1, EM2 by a spur gear train can also be provided.

[0070] In FIG. 11, a tenth example variant of a hybrid transmission 10 according to the invention is shown in a drive train 12. In contrast to the hybrid transmission 10 shown in FIG. 1, a drive output is arranged coaxially to the transmission input shafts 14, 16. Here, the drive output is formed by a gearwheel pair, which is formed from a fixed gear 44 on the countershaft 18 and a fixed gear 46 on an output shaft 48. The output shaft 48 is arranged coaxially to the two transmission input shafts 14, 16. This arrangement makes it possible to establish a direct gear step, i.e., the direct connection of the first transmission input shaft 14 to the output shaft 48 by the shift element F. In this example, the fourth gear step is established as a direct gear. The electric prime mover EM1 is arranged coaxially to the transmission input shafts 14, 16 and is drivingly connected to the second transmission input shaft 16. The second transmission input shaft 16, for all intents and purposes, forms the rotor of the electric prime mover EM1. A pre-ratio (not represented) for the electric prime mover EM1, for example of a planetary design, could also be utilized. It is understood that shift elements can be arranged on the countershaft 18 in this example embodiment as well. It is also conceivable to arrange the shift element D at a transmission input, i.e., adjacent to the internal combustion engine VM. In addition, a second electric prime mover EM2 and/or a separating clutch K0 can be provided.

[0071] The invention was comprehensively described and explained with reference to the drawings and the description. The description and the explanation are to be understood as an example and are not to be understood as limiting. The invention is not limited to the disclosed embodiments. Other embodiments or variations result for a person skilled in the art within the scope of the utilization of the present invention and within the scope of a precise analysis of the drawings, the disclosure, and the following claims.

[0072] In the claims, the words “comprise” and “comprising” do not rule out the presence of further elements or steps. The indefinite article “a” does not rule out the presence of a plurality. A single element or a single unit can carry out the functions of several of the units mentioned in the claims. The mere mention of a few measures in multiple various dependent claims is not to be understood to mean that a combination of these measures cannot also be advantageously utilized.

[0073] 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

[0074] 10 hybrid transmission

[0075] 12 drive train

[0076] 14 first transmission input shaft

[0077] 16 second transmission input shaft

[0078] 18 countershaft

[0079] 20 idler gear of the third spur gear stage

[0080] 22 idler gear of the fourth spur gear stage

[0081] 24 fixed gear of the third spur gear stage

[0082] 26 fixed gear of the fourth spur gear stage

[0083] 28 idler gear of the first spur gear stage

[0084] 30 idler gear of the second spur gear stage

[0085] 32 fixed gear of the first spur gear stage

[0086] 34 fixed gear of the second spur gear stage

[0087] 36 differential

[0088] 38 gear shift matrix

[0089] 40 further countershaft

[0090] 42 fixed gear of the third and fourth spur gear stages

[0091] 44 fixed gear

[0092] 46 fixed gear

[0093] 48 output shaft

[0094] VM internal combustion engine

[0095] EM1 first electric prime mover

[0096] EM2 second electric prime mover

[0097] i1 first spur gear stage

[0098] i2 second spur gear stage

[0099] i3 third spur gear stage

[0100] i4 fourth spur gear stage

[0101] iab output spur gear stage

[0102] iab2 further output spur gear stage

[0103] A shift element

[0104] B shift element

[0105] C shift element

[0106] D shift element

[0107] E shift element

[0108] F shift element

[0109] K0 separating clutch