Hybrid powertrain with two electric machines and an internal combustion engine

Abstract

A drive train for a hybrid motor vehicle having a gearbox input shaft operatively connected to a first electric machine and an internal combustion engine via a first partial drive train to transmit torque and which is operatively connected to a second electric machine via a second partial drive train to transmit torque. The second electric machine is permanently connected to the gearbox input shaft for torque transmission and the first electric machine and the internal combustion engine can be connected to the gearbox input shaft in a coupleable manner to transmit torque. The first electric machine and the second electric machine are arranged coaxially to one another, and driven shaft of the first electric machine is arranged radially inside a driven shaft of the second electric machine. The driven shaft of the first electric machine is mounted on the driven shaft of the second electric machine via a bearing.

Claims

1. A drive train for a hybrid motor vehicle, comprising: a gearbox input shaft operatively connected to a first electric machine and an internal combustion engine via a first partial drive train to transmit torque and which is operatively connected to a second electric machine to transmit torque via a second partial drive train, the second electric machine being permanently connected to the gearbox input shaft to transmit torque and the first electric machine and the internal combustion engine being connectable with the gearbox input shaft in a coupleable manner to transmit torque, wherein the first electric machine and the second electric machine are arranged coaxially to each other, wherein a driven shaft of the first electric machine is arranged radially inside a driven shaft of the second electric machine, wherein the driven shaft of the first electric machine is supported by the driven shaft of the second electric machine via a bearing, and wherein a separating clutch is arranged between the second partial drive train with the second electric machine and the first partial drive train with the first electric machine and the internal combustion engine.

2. The drive train according to claim 1, wherein a rotor of the second electric machine is mounted in a gearbox housing via a first bearing and a second bearing.

3. The drive train according to claim 1, wherein the first electric machine is connected to the internal combustion engine to transmit torque via a first transmission stage, wherein the first transmission stage is provided by a toothing formed on a drive flange of the internal combustion engine and a toothing formed on the driven shaft of the first electric machine, and wherein the toothing of the drive flange is formed as an internally toothed ring gear.

4. The drive train according to claim 1, wherein only one clutch is arranged in the drive train.

5. The drive train according to claim 1, wherein the first electric machine is permanently connected to the internal combustion engine to transmit torque.

6. The drive train according to claim 1, wherein only one transmission stage is formed between the internal combustion engine and the first electric machine.

7. The drive train according to claim 6, wherein the first electric machine and the second electric machine are arranged in an axial direction on one side of the transmission stage and the internal combustion engine is arranged in the axial direction on the other side of the transmission stage.

8. The drive train according to claim 1, wherein the drive train is configured to operate in: a first operating mode for purely electrical driving, in which the clutch is open and only the second electric machine acts as a drive machine for the gearbox input shaft, a second operating mode for a serial hybrid drive, in which the clutch is open, the second electric machine acts as the drive machine for the gearbox input shaft and the internal combustion engine acts as a drive machine for the first electric machine to generate electrical energy, or a third operating mode for a parallel hybrid drive, in which the internal combustion engine and additionally the first electric machine or the second electric machine acts as the drive machine for the gearbox input shaft.

9. A drive train for a hybrid motor vehicle, comprising: a gearbox input shaft operatively connected to a first electric machine and an internal combustion engine via a first partial drive train to transmit torque and which is operatively connected to a second electric machine to transmit torque via a second partial drive train, the second electric machine being permanently connected to the gearbox input shaft to transmit torque and the first electric machine and the internal combustion engine being connectable with the gearbox input shaft in a coupleable manner to transmit torque, wherein the first electric machine and the second electric machine are arranged coaxially to each other, wherein a driven shaft of the first electric machine is arranged radially inside a driven shaft of the second electric machine, wherein the driven shaft of the first electric machine is supported by the driven shaft of the second electric machine via a bearing, wherein the first electric machine is connected to the internal combustion engine to transmit torque via a first transmission stage, wherein the first transmission stage is provided by a toothing formed on a drive flange of the internal combustion engine and a toothing formed on the driven shaft of the first electric machine, and wherein the toothing of the drive flange is formed as an internally toothed ring gear.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure will be explained further in the following by the drawings, in which:

(2) FIG. 1 is a schematic diagram of a drive train according to the disclosure for a hybrid motor vehicle,

(3) FIG. 2 is a schematic view of the drive train according to the disclosure, having a first bearing design,

(4) FIG. 3 is a schematic view of the drive train having a second bearing design,

(5) FIG. 4 is a longitudinal sectional view of the drive train from FIG. 3, and

(6) FIG. 5 is an enlarged view of part of the drive train shown in the longitudinal sectional view in FIG. 4.

(7) The drawings are of a purely schematic nature and are used solely to provide understanding of the disclosure. Like elements are denoted by the same reference signs.

DETAILED DESCRIPTION

(8) FIG. 1 is a schematic diagram of a drive train 1 according to the disclosure for a hybrid motor vehicle. In the drive train 1, a gearbox input shaft 2 is operably connected in a couplable manner by means of a first partial drive train 3 to a first electric machine (e-machine) 4 and an internal combustion engine (ICE) 5 for torque transmission. The gearbox input shaft 2 is permanently operably connected by means of a second partial drive train 6 to a second electric machine (e-machine) 7. The second electric machine 7 is connected to the gearbox input shaft 2 in each operating state, whereas the first electric machine 4 and the internal combustion engine 5 can be decoupled from the gearbox input shaft 2 by means of a clutch/separating clutch 8.

(9) The first partial drive train 3 can thus be connected by means of the separating clutch 8 to the second partial drive train 6 and thus to the gearbox input shaft 2 for torque transmission. The first electric machine 4 is arranged coaxially with the second electric machine 7. The internal combustion engine 5 is arranged axially parallel to the first electric machine 4 and the second electric machine 7. The internal combustion engine 5 is permanently connected to, that is to say cannot be decoupled from, the first electric machine 4 by means of a first transmission stage (i.sub.1) 9 for torque transmission. The first transmission stage 9 is formed by a toothing 10 on a drive flange 11 of the internal combustion engine 5 and a toothing 12 on a driven shaft 13 of the first electric machine 4. The first transmission stage 9, starting from the internal combustion engine 5, is a speed-increasing ratio, that is to say i.sub.1<1. The driven shaft 13 can also function as a drive shaft when the first electric machine 4 is used in a generator mode. However, for the sake of simplicity, the driven/drive shaft 13 of the first electric machine 4 will be referred to in the following as driven shaft 13.

(10) The first electric machine 4 comprises a rotor 14 and a stator 15 which is arranged concentrically with and radially outside said rotor. The rotor 14 is rigidly connected by means of a rotor support 16 to the driven shaft 13 of the first electric machine 4. The driven shaft 13 is connected in a rotationally fixed manner to part of the separating clutch 8.

(11) The second electric machine 7 comprises a rotor 17 and a stator 18 which is arranged concentrically with and radially outside said rotor. The rotor 17 is rigidly connected by means of a rotor support 19 to a driven shaft 20 of the second electric machine 7. The driven shaft 20 can also function as a drive shaft when the second electric machine 7 is used in a generator mode. However, for the sake of simplicity, the driven/drive shaft 20 of the second electric machine 7 will be referred to in the following as driven shaft 20. The driven shaft 20 of the second electric machine 7 is connected in a rotationally fixed manner to another part of the separating clutch 8 so that the driven shaft 20 of the second electric machine 7 is coupled in a rotationally fixed manner to the driven shaft 13 of the first electric machine 4 when the separating clutch 8 is closed.

(12) The driven shaft 20 of the second electric machine 7 is permanently connected to, that is to say cannot be decoupled from, the gearbox input shaft 2 or a countershaft 21 for torque transmission, by means of a second transmission stage (i.sub.2) 22. The second transmission stage 22 is formed by a toothing 23 on the driven shaft 20 of the second electric machine 7 and a toothing 24 on the countershaft 21. Starting from the driven shaft 20 of the second electric machine 7, the second transmission stage 22 is a speed-decreasing ratio, i.e. i.sub.2>1.

(13) The countershaft 21 is connected by means of a third transmission stage (i.sub.3) 26 to a differential gear 25 for torque transmission. The third transmission stage 26 is formed by a toothing 27 on the countershaft 21 and a toothing 28 on the differential gear 25. The third transmission stage 26, starting from the countershaft 21, is a speed-decreasing ratio, i.e. i.sub.3>1. A parking lock 29 is formed by means of an interlocking connection 30 to the countershaft 21 or to an integrated toothing 31 on the countershaft 21.

(14) FIG. 2 is a schematic view of the drive train 1 according to the disclosure. The rotor 14 of the first electric machine 4 is mounted in a gearbox housing (not shown) by means of a first bearing 32 and a second bearing 33. The rotor 17 of the second electric machine 4 is mounted in the gearbox housing by means of a first bearing 34 and on the driven shaft 13 of the first electric machine 4 by means of a second bearing 35. The driven shaft 20 is mounted on the driven shaft 13 by means of an additional bearing 36. The driven shaft 20 of the second electric machine 7 is in the form of a hollow shaft which the driven shaft 13 of the first electric machine 4 is arranged radially inside. The first electric machine 4 is arranged in the axial direction on a side of the second electric machine 7 facing away from the internal combustion engine. The separating clutch 8 is arranged in the axial direction between the first electric machine 4 and the second electric machine 7. The separating clutch 8 is arranged in the axial direction on the side of the second electric machine 7 facing away from the internal combustion engine.

(15) The first transmission stage 9 is arranged in the axial direction between the internal combustion engine 5 and the second electric machine 7 and thus also between the internal combustion engine 5 and the first electric machine 4. The second transmission stage 22 is arranged in the axial direction between the first transmission stage 9 and the second electric machine 7. The bearing 36 is arranged in the axial direction at the level of the second transmission stage 22

(16) The internal combustion engine 5 is connected to the driven shaft 13 of the first electric machine 4 by means of a vibration damper 37 and a slip clutch 38. The drive flange 11 of the internal combustion engine 5 is mounted in the gearbox housing by means of two bearings 39. The toothing 10 of the drive flange 11 is in the form of an internally toothed ring gear. The toothing 12 of the driven shaft 13 and the toothing 23 of the driven shaft 20 are each in the form of an externally toothed spur gear. The countershaft 21 is mounted in the gearbox housing by means of two bearings 40. The toothings 24, 27 of the countershaft 21 are each in the form of an externally toothed spur gear. The toothing 28 of the differential gear 25 is in the form of an externally toothed spur gear.

(17) FIG. 3 shows an alternative system for mounting the driven shaft 13 and the driven shaft 20. The rest of the features correspond to those from FIG. 2 and, for the sake of simplicity, are not described again. The rotor 17 of the second electric machine 7 is mounted in the gearbox housing by means of the first bearing 34 and a second bearing 41. The rotor 14 of the first electric machine 4 is mounted in the gearbox housing by means of the first bearing 32 and on the driven shaft 20 of the second electric machine 7 by means of a second bearing 42. The driven shaft 13 is mounted on the driven shaft 20 by means of the additional bearing 36.

(18) FIGS. 4 and 5 show a longitudinal sectional view of the drive train 1. In this case, in one embodiment, the separating clutch 8 is in the form of a multi-plate clutch which is operated by means of a hydraulic central clutch release mechanism 43. In another embodiment, the separating clutch 8 is in the form of a dog clutch in which a sliding sleeve 44 can be moved in an electrically driven manner by an electric motor 45 to open or close the separating clutch 8.

(19) The internal combustion engine 5 is connected to the drive flange 11 by means of a crankshaft flange 46 and by means of the vibration damper 37, which is in the form of a torsional vibration damper. In FIGS. 4 and 5, a gearbox housing 47 is also shown in which the driven shaft 13 is mounted by means of the bearings 32, 42, the driven shaft 20 is mounted by means of the bearings 34, 41, the drive flange 11 is mounted by means of the bearings 39, and the countershaft 21 is mounted by means of the bearings 40. The bearings 32, 34, 41, 42 are in the form of ball roller bearings, whereas the bearings 39 are in the form of tapered roller bearings in an O arrangement, and the bearings 40 are in the form of tapered roller bearings in an X arrangement.

(20) The separating clutch 8 in the form of a multi-plate clutch in FIG. 5 comprises an outer plate carrier 48 which is connected in a rotationally fixed manner by means of a shaft-hub connection to the driven shaft 20, and an inner plate carrier 49, which is formed integrally with the rotor support 16 of the first electric machine 4.

LIST OF REFERENCE NUMBERS

(21) 1 drive train 2 gearbox input shaft 3 first partial drive train 4 first electric machine 5 internal combustion engine 6 second partial drive train 7 second electric machine 8 separating clutch 9 first transmission stage 10 toothing 11 drive flange 12 toothing 13 drive/driven shaft 14 rotor 15 stator 16 rotor support 17 rotor 18 stator 19 rotor support 20 drive/driven shaft 21 countershaft 22 second transmission stage 23 toothing 24 toothing 25 differential gear 26 third transmission stage 27 toothing 28 toothing 29 parking lock 30 interlocking connection 31 integrated toothing 32 first bearing 33 second bearing 34 first bearing 35 second bearing 36 bearing 37 vibration damper 38 slip clutch 39 bearings 40 bearings 41 second bearing 42 second bearing 43 central clutch release mechanism 44 sliding sleeve 45 electric motor 46 crankshaft flange 47 gearbox housing 48 outer plate carrier 49 inner plate carrier