DRIVE UNIT AND DRIVE ASSEMBLY

Abstract

A drive unit for a drive train of an electrically drivable motor vehicle, in particular a hybrid motor vehicle, and to a drive assembly. The drive unit is for a drive train of an electrically drivable motor vehicle, and includes a first electric rotary machine for generator operation and a second electric rotary machine for drive motor operation, and a transmission. A rotor of the first electric rotary machine is for direct mechanical coupling to an output element of an internal combustion engine, and a rotor of the second electric rotary machine is or can be rotationally coupled to an input of the transmission, with no torque-transmitting connection being provided between the first electric rotary machine and the transmission.

Claims

1. A drive unit for a drive train of an electrically drivable motor vehicle, the drive unit comprising: a first electric rotary machine adapted for generator operation; a second electric rotary machine adapted for drive motor operation; a transmission; a rotor of the first electric rotary machine is configured for direct mechanical coupling to an output element of an internal combustion engine; a rotor of the second electric rotary machine is coupled or couplable to an input of the transmission in a rotationally fixed manner; and there is no torque-transmitting connection between the first electric rotary machine and the transmission.

2. The drive unit according to claim 1, wherein the first electric rotary machine comprises an inner rotor machine.

3. The drive unit according to claim 1, wherein the first electric rotary machine comprises an outer rotor machine.

4. The drive unit according to claim 1, wherein the rotor of the first electric rotary machine comprises a flywheel for operating the internal combustion engine.

5. The drive unit according to claim 1, wherein axes of rotation of the rotors of the first and second electric rotary machines are arranged parallel or coaxially.

6. The drive unit according to claim 1, wherein the first electric rotary machine is arranged in a generator compartment which is spatially separate from the transmission.

7. The drive unit according to claim 1, wherein the transmission comprises at least one or more transmission ratio stages.

8. The drive unit according to claim 1, wherein at least one of the first electric rotary machine or the second electric rotary machine is configured for cooling by a fluid.

9. The drive unit according to claim 1, wherein the first and second electric rotary machines are connected to one another directly in an electrically conductive manner or via power electronics or are connected to one another by an electrical storage element.

10. A drive assembly comprising the drive unit according to claim 1, and an internal combustion engine which is directly coupled in a rotationally fixed manner to the rotor of the first electric rotary machine by an output element of the internal combustion engine.

11. A drive unit for a drive train of an electrically drivable motor vehicle, the drive unit comprising: a first electric rotary machine having a first rotor and being adapted for generator operation; a second electric rotary machine having a second rotor; a transmission; the first rotor is configured for direct mechanical coupling to an output element of an internal combustion engine to generate electricity; the second rotor is coupled or couplable rotationally fixed to an input of the transmission; wherein the first electric rotary electrical machine is in electrical connection with the second electric rotary machine; and there is no torque-transmitting connection between the first electric rotary machine and the transmission.

12. The drive unit according to claim 11, wherein the first electric rotary machine comprises an inner rotor machine.

13. The drive unit according to claim 11, wherein the first electric rotary machine comprises an outer rotor machine.

14. The drive unit according to claim 11, wherein the first rotor comprises a flywheel of the internal combustion engine.

15. The drive unit according to claim 11, wherein axes of rotation of the first and second rotors are arranged parallel or coaxially.

16. The drive unit according to claim 11, wherein the first electric rotary machine is arranged in a generator compartment which is spatially separate from the transmission.

17. The drive unit according to claim 11, wherein the transmission comprises at least one or more transmission ratio stages.

18. The drive unit according to claim 11, wherein at least one of the first electric rotary machine or the second electric rotary machine is configured for cooling by a fluid.

19. The drive unit according to claim 11, wherein the first and second electric rotary machines are connected to one another directly via power electronics or are connected to one another by an electrical storage element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0074] The disclosure above is explained in detail below against the significant technical background with reference to the accompanying drawings, which show preferred embodiments. The disclosure is not limited in any way by the purely schematic drawings, wherein it should be noted that the embodiments shown in the drawings are not limited to the dimensions shown. In the drawings:

[0075] FIG. 1: shows a schematic representation of a drive assembly with a drive unit in a first embodiment;

[0076] FIG. 2: shows a schematic representation of a drive assembly with a drive unit in a second embodiment;

[0077] FIG. 3: shows a sectional representation of the drive assembly with the drive unit in the second embodiment; and

[0078] FIG. 4: shows a schematic representation of the cooling system of the drive assembly with the drive unit.

DETAILED DESCRIPTION

[0079] First, the drive unit 1 and the drive assembly 2 are explained by means of the schematic representations in FIGS. 1 and 2.

[0080] The drive units 1 shown in these figures comprise a first electric rotary machine 20 and a second electric rotary machine 30 arranged in a housing 10.

[0081] The first electric rotary machine 20 of the drive unit 1 shown in FIG. 1 is designed as an outer rotor machine, so that the rotor 21 of the first electric rotary machine 20 is arranged radially outside the stator 22 of the first electric rotary machine 20.

[0082] The first electric rotary machine 20 of the drive unit 1 shown in FIG. 2 is designed as an inner rotor machine so that the rotor 21 of the first electric rotary machine 20 is arranged radially within the stator 22 of the first electric rotary machine 20.

[0083] The second electric rotary machine is designed as an inner rotor machine in both exemplary embodiments shown in FIGS. 1 and 2, so that the rotor 31 of the second electric rotary machine 30 is arranged radially within the stator 32 of the second electric rotary machine 30.

[0084] In both exemplary embodiments shown in FIGS. 1 and 2, the axis of rotation 23 of the first electric rotary machine 20 and the axis of rotation 33 of the second electric rotary machine 30 are arranged coaxially.

[0085] In order to form the drive assembly 2, the rotor 21 of the first electric rotary machine 20 is directly coupled to an output element 71 of the internal combustion engine 70. In particular, this output element 71 may be the crankshaft of the internal combustion engine 70.

[0086] This means that the internal combustion engine 70 or the output element 71 thereof is coupled to the rotor 21 of the first electric rotary machine 20 by means of a direct connection 80 and, consequently, without changing the torque, particularly without intermediate engagement of a clutch or a transmission as well as particularly without intermediate engagement of a torque-transmitting element with circumferential clearance.

[0087] This enables the design of the drive unit 1 or the drive assembly 2 in a manner which is particularly very space-saving axially.

[0088] The rotor 31 of the second electric rotary machine 30 is connected in a rotationally fixed manner to a shaft 42 which forms an input 41 of a transmission 40.

[0089] This enables the torque provided by the second electric rotary machine 30 to be transmitted to the transmission 40 shown.

[0090] This transmission 40 comprises a first transmission ratio stage 43 as well as a second transmission ratio stage 44. The first transmission ratio stage 43 is implemented on the shaft 42 via a first gear wheel 51 and on an intermediate shaft 50 via a second gear wheel 52 meshing therewith. The shaft 42 is mounted in the housing 10 by means of pivot bearings.

[0091] The second transmission ratio stage 44 is implemented via a third gear wheel 53, which is arranged on the intermediate shaft 50, and a drive element 61 of a differential gear 60, which has an outer toothing, with the toothing of the third gear wheel 53 meshing therewith.

[0092] In this manner, the torque provided from the second electric rotary machine 30 can be transmitted to the differential gear 60 via the transmission 40, with the torque being supplied from the differential gear to the wheel drive shafts 62.

[0093] There is an electrical connection between the first electric rotary machine 20 and the second electric rotary machine 30, wherein this electrical connection 90 advantageously includes a battery (not shown here) as an electrical storage element and/or power electronics (not shown here).

[0094] The drive assembly 2 makes it possible for the first electric rotary machine 20 to be driven as a generator during operation of the internal combustion engine 70 and, accordingly, mechanical energy is converted to electrical energy. This electrical energy can be provided via the electrical connection 90 of the second electric rotary machine 30, which converts the electrical energy into mechanical energy and generates a torque during operation of the electric motor. This torque can be used to propel a motor vehicle.

[0095] In this case, it is not provided that the torque from the first electric rotary machine 20 is provided from the electric motor and is used to propel a motor vehicle. Accordingly, there are also no torque-impacting transmission elements needed between the first electric rotary machine 20 and an output and/or between the first electric rotary machine 20 and the internal combustion engine 70, so that the drive assembly 2 designed in this manner has very low installation space requirements.

[0096] In an advantageous design with an electrical storage element, electrical energy generated by the first electric rotary machine 20 can be intermediately stored before it is converted into mechanical energy by the second electric rotary machine 30.

[0097] In addition, this enables an increase or shifting of the load point which ensures a higher level of efficiency when operating the drive unit.

[0098] The drive assembly 2 enables the increasing of the range in electric-motor driving operation in a simple, space-saving manner, with the conversion of chemical energy in the internal combustion engine 70, but with an optimum level of efficiency of the internal combustion engine 70.

[0099] FIG. 3 shows the drive unit 1 shown in the schematic representation in FIG. 2 in a sectional view.

[0100] In addition to the components or units mentioned already as relates to FIG. 2, FIG. 3 shows that the first electric rotary machine 20, which is designed as a generator, is arranged in a generator compartment 100, which is essentially spatially separate from a gear compartment 45, in which the elements of the transmission 40 are arranged.

[0101] This enables separate lubrication and/or cooling of the components in both compartments 45, 100.

[0102] Furthermore, FIG. 3 shows power electronics 110, which are arranged on the upper side of the drive unit 1, connected to the housing 10.

[0103] Further components of the drive unit shown in FIG. 3 include a parking lock 111, as well as an oil collection container 112, and a high voltage terminal 113 for the electrical connection of the electric rotary machines 20, 30.

[0104] FIG. 4 shows, in a schematic manner, an option for cooling and lubricating the drive unit 1. This figure shows a coolant inlet 120, which is configured to supply coolant from a cooling element to the power electronics and, accordingly, also to the transmission.

[0105] From there, the coolant reaches a second coolant circuit 122 assigned to the stator of the second electric rotary machine, and then a first coolant circuit 121, which is assigned to the stator of the first electric rotary machine, via an overflow area 124.

[0106] The coolant can then be returned to the external cooling element via a coolant outlet 123.

[0107] Lubrication is implemented by an oil collection element 130, among other things, from which oil which is thrown off by the differential gear 80 is collected. From there, the oil can be returned to a return 132 by means of an oil distribution element 131, particularly the shaft, with the return transporting the oil to a sump.

[0108] The oil from the oil collection element is advantageously supplied to all necessary locations (e.g. bearings/toothing) via an oil distribution element for lubrication.

[0109] The drive unit and drive assembly proposed here enable optimum operation in an economical design and space-saving manner.

LIST OF REFERENCE SYMBOLS

[0110] 1 Drive unit [0111] 2 Drive assembly [0112] 10 Housing [0113] 20 First electric rotary machine [0114] 21 Rotor of the first electric rotary machine [0115] 22 Stator of the first electric rotary machine [0116] 23 Axis of rotation of the first electric rotary machine [0117] 30 Second electric rotary machine [0118] 31 Rotor of the second electric rotary machine [0119] 32 Stator of the second electric rotary machine [0120] 33 Axis of rotation of the second electric rotary machine [0121] 40 Transmission [0122] 41 Transmission input [0123] 42 Shaft [0124] 43 First transmission ratio stage [0125] 44 Second transmission ratio stage [0126] 45 Gear compartment [0127] 50 Intermediate shaft [0128] 51 First gear wheel [0129] 52 Second gear wheel [0130] 53 Third gear wheel [0131] 60 Differential gear [0132] 61 Drive element of the differential gear [0133] 62 Wheel drive shaft [0134] 70 Internal combustion engine [0135] 71 Output element of the internal combustion engine [0136] 80 Direct connection [0137] 90 Electrical connection [0138] 100 Generator compartment [0139] 110 Power electronics [0140] 111 Parking lock [0141] 112 Oil collection container [0142] 113 High-voltage terminal [0143] 120 Coolant inlet [0144] 121 First coolant circuit [0145] 122 Second coolant circuit [0146] 123 Coolant outlet [0147] 124 Overflow area [0148] 130 Oil collection element [0149] 131 Oil distribution element [0150] 132 Oil return to sump