Drive unit for a drive train of an electrically driveable motor vehicle, and drive assembly and motor vehicle equipped with same

Abstract

A drive unit and a drive assembly and a motor vehicle. The drive unit includes a first electric machine and a second electric machine and an output shaft, wherein a rotor of the second electric machine is connected to the output shaft for conjoint rotation. The drive unit further includes a disconnect clutch by which a rotor of the first electric machine can be connected to the output shaft. The drive unit further includes power electronics for controlling at least one of the two electric machines and a flow system for implementing a flow of a coolant, and the drive unit, being a component in the flow system, further includes a heat exchanger by which the coolant can be cooled. The drive unit and the drive assembly constitute equipment that allows control of individual assemblies in an efficient manner and with a low space requirement.

Claims

1. A drive unit for a drivetrain of an electrically drivable motor vehicle, the drive unit comprising: a first electric machine having a rotor; a second electric machine having a rotor; a housing in which the first electric machine and the second electric machine are arranged at least in some regions; an output shaft to which the rotor of the second electric machine is connected for conjoint rotation; a disconnect clutch by which the rotor of the first electric machine is connectable to the output shaft for torque transmission; power electronics configured to control at least one of the two electric machines_, wherein the power electronics are arranged on a radial outer side of the housing; a flow system configured to implement a flow of a coolant for at least partial cooling of the power electronics; and a heat exchanger adapted to cool the coolant.

2. The drive unit according to claim 1, wherein the power electronics are configured to control both electric machines.

3. The drive unit according to claim 1, wherein the flow system has a fluidic interface adapted for connecting the flow system to a cooling system of a motor vehicle to be equipped with the drive unit.

4. The drive unit according to claim 1, wherein the power electronics are further configured to control at least one of a rotor position sensor or a temperature sensor configured for determining a temperature in at least one of the two electric machines.

5. The drive unit according to claim 1, wherein the power electronics comprise an electronics housing and at least one connecting element with which the electronics housing is mechanically fixed to the housing of the drive unit.

6. The drive unit according to claim 1, wherein the power electronics have at least one control interface configured for connecting to at least one of a control device of a motor vehicle or an energy store.

7. The drive unit according to claim 1, wherein the flow system is formed at least partially by channels in the housing.

8. A drive assembly comprising: a drive unit according to claim 1, and an internal combustion engine that is couplable to the rotor of the first electric machine for conjoint rotation.

9. A motor vehicle comprising: a drive assembly according to claim 8, and a motor vehicle cooling system to which the flow system of the drive unit is fluidically coupled via a fluidic interface of the flow system.

10. A drive unit for a drivetrain of an electrically drivable motor vehicle, the drive unit comprising: a first electric machine having a rotor; a second electric machine having a rotor; a housing in which the first electric machine and the second electric machine are arranged within; an output shaft to which the rotor of the second electric machine is connected for conjoint rotation; a disconnect clutch by which the rotor of the first electric machine is connectable to the output shaft for torque transmission; power electronics configured to control at least one of the two electric machines, the power electronics being arranged in an electronics housing, wherein the power electronics comprises at least one connecting element with which the electronics housing is mechanically fixed to the housing of the drive unit; a flow system configured to implement a flow of a coolant for at least partial cooling of the power electronics; and a coolant connection of the flow system in the electronics housing.

11. The drive unit according to claim 10, further comprising a heat exchanger connected to the flow system.

12. The drive unit according to claim 10, wherein the electronics housing is arranged on the housing.

13. The drive unit according to claim 12, wherein the flow system is formed at least partially by channels in the housing.

14. The drive unit according to claim 10, wherein the flow system has a fluidic interface adapted for connecting the flow system to a cooling system of a motor vehicle.

15. The drive unit according to claim 10, wherein the power electronics are configured to control both electric machines.

16. The drive unit according to claim 10, wherein the power electronics are further configured to control at least one of a rotor position sensor or a temperature sensor configured for determining a temperature in at least one of the two electric machines.

17. The drive unit according to claim 10, wherein the power electronics have at least one control interface configured for connecting to at least one of a control device of a motor vehicle or an energy store.

18. A drive unit for a drivetrain of an electrically drivable motor vehicle, the drive unit comprising: a first electric machine having a rotor; a second electric machine having a rotor; a first shaft to which the rotor of the first electric machine is connected for conjoint rotation; an output shaft to which the rotor of the second electric machine is connected for conjoint rotation, wherein the first shaft is positioned radially inside the output shaft; a disconnect clutch by which the rotor of the first electric machine is connectable to the output shaft for torque transmission; power electronics configured to control at least one of the two electric machines; a flow system configured to implement a flow of a coolant for at least partial cooling of the power electronics; and a heat exchanger adapted to cool the coolant.

19. The drive unit according to claim 18, wherein: the first electric machine includes stator; and the second electric machine includes a stator; wherein the rotor of the first electric machine is positioned closer to an axis of rotation of the drive unit than the stator of the first electric machine, and the rotor of the second electric machine is positioned closer to the axis of rotation of the drive unit than the stator of the second electric machine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The embodiments described above are explained in detail below based on the relevant technical background with reference to the associated drawings, which show preferred embodiments. The disclosure is in no way restricted by the purely schematic drawings, although it should be noted that the embodiments shown in the drawings are not limited to the dimensions shown. In the figures:

(2) FIG. 1: shows a drive unit according to an embodiment in a sectional view,

(3) FIG. 2: shows a drive unit according to an embodiment in a perspective view,

(4) FIG. 3: shows a detail from the drive unit shown in FIG. 2 in a perspective view,

(5) FIG. 4: shows a plan view of the power electronics,

(6) FIG. 5: shows the power electronics alone in a perspective view,

(7) FIG. 6: shows the drive unit according to an embodiment and the power electronics prior to assembly in a perspective view, and

(8) FIG. 7: shows a sectional view of the drive unit.

DETAILED DESCRIPTION

(9) FIG. 1 shows a drive unit 100 for a drivetrain of an electrically drivable motor vehicle, in particular a hybrid vehicle, which has a first electric machine 110 and a second electric machine 120, both of which are arranged on a common axis of rotation 101. The rotor 111 of the first electric machine 110 is arranged coaxially to the axis of rotation 101 and also to the rotor 121 of the second electric machine 120. The stator 112 of the first electric machine 110 and also the stator 122 of the second electric machine 120 are accommodated in a housing 102 of the drive unit 100.

(10) The rotor 111 of the first electric machine is connected to a first shaft 130 for conjoint rotation. The rotor 121 of the second electric machine 120 is connected to an output shaft 140 for conjoint rotation, which can also be referred to as a transmission input shaft.

(11) Furthermore, the drive unit 100 comprises a disconnect clutch 150 with which the first electric machine 110 and thus an internal combustion engine connected to the first shaft 130 connected for conjoint rotation to the rotor 111 of the first electric machine 110 can be or is connected to the output shaft for torque transmission.

(12) In the embodiment shown here, the first shaft 130 is designed in two parts, namely made up of a central hollow shaft 132 and a hub 133 positioned on this hollow shaft 132 and connected thereto for conjoint rotation, wherein the hub 133 is also connected to the rotor 111 of the first electric machine 110 in a fixed manner.

(13) The hub 133 forms the radial inner side 151 of the disconnect clutch 150 or is firmly connected to this input side of the disconnect clutch 150.

(14) The radial outer side 152 of the disconnect clutch 150, which realizes the output side of the disconnect clutch 150, is connected to the output shaft 140 for conjoint rotation.

(15) The disconnect clutch 150 is a switchable clutch that can be switched from an open state to a closed state and vice versa. For this purpose, the disconnect clutch 150 is assigned an actuation system 153.

(16) In this way, when the disconnect clutch 150 is closed, a torque can be transmitted from the first shaft 130 to the output shaft 140 or vice versa.

(17) In the embodiment shown here, it is thus provided that the two electric machines 110, 120 are arranged in series, wherein the rotors 111, 121 of the two electric machines 110, 120 or their axes of rotation are arranged coaxially.

(18) The first shaft 130 or its central hollow shaft 132 runs radially inside the output shaft 140, whereby the overall volume required for the drive unit 100 can be made small.

(19) Furthermore, the drive unit 100 shown here comprises a transmission 160 which is in operative connection with the output shaft 140 of the drive unit 100, also referred to as the transmission input shaft, so that a torque made available by the output shaft 140 or the rotary movement realized by the output shaft 140 can be directed stepped up or stepped down via the transmission 160 to a further transmission unit of a motor vehicle, or can also be transferred directly to drive wheels of a motor vehicle.

(20) In the embodiment shown here, this transmission 160 comprises a differential transmission 170.

(21) Furthermore, the transmission 160 comprises a first gearwheel 161, which meshes with an external toothing 141 on the output shaft 140. A second transmission stage 162 is thus realized in the drive unit 100 by the first gearwheel 161. This first gearwheel 161 is coupled to a countershaft 163 of the gear 160 for conjoint rotation, the external toothing 164 of which in turn meshes with an input gearwheel 171 of the differential gear 170, thereby realizing a third transmission stage 172.

(22) The drive unit 100 is part of a likewise illustrated embodiment of a drive assembly 200 according to the invention.

(23) This drive assembly 200 additionally has an internal combustion engine (not shown here) which, when connected to the connection 210 shown, is coupled to the rotor 111 of the first electric machine 110 for conjoint rotation via the first shaft 130 orwith the interposition of a further couplingcan be coupled thereto.

(24) The illustrated drive assembly 200 is designed in such a way that a first transmission stage 142 is formed between the connection 210 for an internal combustion engine (not shown here) and the first shaft 130, which is connected to the rotor 111 of the first electric machine 110 for conjoint rotation, for the purpose of transmitting the speed of the rotary movement realized by the internal combustion engine or its connection 210 to the first shaft 130.

(25) For this purpose, an output element 220 of the internal combustion engine is provided, which can have a damper unit 221 or a clutch 222 for opening and closing the torque transmission path between the internal combustion engine and the drive unit 100, or a combination shown of a damper unit 221 and a clutch 222.

(26) Furthermore, the output element 220 comprises an internally toothed gearwheel 223 as a component, which meshes with an external toothing 131 of the first shaft 130 and thus realizes a first transmission stage 142.

(27) It can be seen that, in the exemplary embodiment shown here, an axis of rotation of the output element 220 is offset laterally to the axis of rotation 101 of the drive unit 100.

(28) In this way, a rotary movement generated by the internal combustion engine (not shown here) can be directed via the output element 220 and the first transmission stage 142 on the first shaft 130, so that the rotor 111 of the first electric machine 110 located thereon can be set in rotary movement in order to operate as a generator.

(29) When the disconnect clutch 150 closes, the applied rotary movement can be transmitted from the first shaft 130, possibly amplified by an electric motor drive through the first electric machine 110, to the output shaft 140. Because of the conjointly rotating connection of the rotor 122 of the second electric machine 120 to the output shaft 140, a torque provided by the second electric machine 120 can also be applied to the output shaft 140.

(30) Alternatively, when the disconnect clutch 150 is opened, only the second electric machine 120 can be operated alone in order to rotate the output shaft 140.

(31) The rotary movement of the output shaft 140 is directed via its external toothing 141 to the first gear 161 of the connected gear 160, wherein the second transmission stage 162 is realized.

(32) From the first gear 161, the torque or the rotary movement is directed to the countershaft 163, from which it is fed to the differential transmission 170 via the input gearwheel 171.

(33) The torque is transferred from the differential transmission 170 to the wheel drive shafts (not shown here) or, if necessary, a further transmission to step up or down the torque or the speed.

(34) The illustrated drive assembly 200 can realize a wide variety of driving states, such as operation of the internal combustion engine alone to drive a motor vehicle, or with the addition of the second electric machine and/or the first electric machine, as well as simultaneous generator operation of the first electric machine during operation of the internal combustion engine and/or the second electric machine, as well as operation of the second electric machine alone, or recuperation operation of the first electric machine and/or the second electric machine.

(35) FIG. 2 shows a drive unit in a perspective view, in which it can be clearly seen that the power electronics 1 are arranged radially outside on the housing 102 and are located in an electronics housing 3 which is closed with a cover 4.

(36) A battery connection 6 is located on the power electronics 1, which thus forms a control interface for connecting an energy store.

(37) In the cover 4 of the electronics housing 3, a connection 5 is provided to a vehicle control unit (not shown here) which can in particular be designed as a so-called CAN connection. This connection to a vehicle control unit 5 is thus also a control interface for the controlling connection with the motor vehicle, in which the drive unit according to the invention is to be integrated.

(38) Mechanically connected to the power electronics 1, a heat exchanger 40 is also provided, which can be designed as a heat exchanging device.

(39) FIG. 3 shows the power electronics again in a perspective view, wherein the coolant connection 50 is clearly visible here, which forms a fluidic interface for connecting the power electronics to a cooling system. This coolant connection 50 comprises an inlet 51 into the housing 102 for the inlet of the coolant, as well as an outlet 52 from the housing 102 for the outlet of the coolant.

(40) FIG. 4 shows the power electronics in the assembled state from above, wherein a first connecting element 10 assigned to the first electric machine is clearly visible here as well as a second connecting element 20 assigned to the second electric machine. These connecting elements 10, 20 are used for the mechanical connection and, if necessary, also for the fluid sealing of the power electronics 1 on the housing 102.

(41) The connecting elements 10, 20 can be seen more clearly in FIG. 5, which shows the power electronics 1 in a perspective view. It can be seen here that the two connecting elements 10, 20 are arranged on the underside of the electronics housing 3, wherein these are sealed off from the electronics housing 3 by a first radial seal 11 and a second radial seal 21.

(42) Furthermore, the assembly direction 60 can be seen from FIG. 5, which indicates that the electronics unit 1 is to be placed in the radial direction on the housing 102 of the drive unit 100 during assembly.

(43) FIG. 6 essentially shows the assembly process, wherein the assembly direction 60 is also indicated here in order to show that during assembly the power electronics 1 is approached in the radial direction of the radial outer side 103 of the housing 102, wherein radial direction is to be understood as a direction perpendicular to the axis of rotation 101.

(44) It can also be seen that, when this movement is carried out along the assembly direction 60, the second connecting element 20 comes into engagement with a receptacle 105 in the housing 102, which forms a counter-sealing surface for the connecting element 20.

(45) FIG. 7 shows the flow system 30 in a section through the drive unit 100. It is defined by a flow path 32 which leads through channels 104 in the housing 102. Coolant 31 is directed through these channels 104.

(46) It can be seen that the coolant 31 enters the housing 102 through the inlet 51 and then passes through an inlet 33 into the power electronics 1 or into the electronics housing 3. There the coolant 31 flowed through the electronics housing and passes through an outlet 34 back into a channel in the housing 102.

(47) From there, the coolant 31 passes into the heat exchanger 40, where the heat absorbed by the coolant 31 is given off, preferably to a further fluid, which is not shown here and also flows through the heat exchanger 40.

(48) Thereafter, the coolant 31 can be transmitted (in a manner not shown) to a cooling system of a motor vehicle in which the drive unit is integrated.

(49) The present drive unit and the drive assembly equipped with same constitute equipment that allows control of individual assemblies of the drive unit in an efficient manner and with a low space requirement.

LIST OF REFERENCE SYMBOLS

(50) 1 Power electronics 2 Control connection 3 Electronics housing 4 Cover of the electronics housing 5 Connection to the vehicle control unit 6 Battery connection 10 First connecting element 11 First radial seal 20 Second connecting element 21 Second radial seal 30 Flow system 31 Coolant 32 Flow path 33 Inlet into the power electronics 34 Outlet from the power electronics 40 Heat exchanger 50 Coolant connection 51 Inlet into the housing 52 Outlet from the housing 60 Assembly direction 100 Drive unit 101 Axis of rotation 102 Housing 103 Radial outer side of the housing 104 Channel in the housing 105 Receptacle 110 First electric machine 111 Rotor of the first electric machine 112 Stator of the first electric machine 120 Second electric machine 121 Rotor of the second electric machine 122 Stator of the second electric machine 130 First shaft 131 External toothing of the first shaft 132 Central hollow shaft 133 Hub 140 Output shaft 141 External toothing of the output shaft 142 First transmission stage 150 Disconnect clutch 151 Radial inner side of the disconnect clutch 152 Radial outer side of the disconnect clutch 153 Actuation system 160 Transmission 161 First gearwheel 162 Second transmission stage 163 Countershaft 164 External toothing of the countershaft 170 Differential transmission 171 Input gearwheel 172 Third transmission stage 200 Drive assembly 210 Connection for an internal combustion engine 220 Output element 221 Damper unit 222 Clutch 223 Internally toothed gearwheel