Drive unit for a powertrain of an electrically driveable motor vehicle, and drive assembly

Abstract

A drive unit for a powertrain of an electrically driveable motor vehicle is disclosed having a first electrical machine and a second electrical machine and an output shaft, wherein a rotor of the second electrical machine is connected to the output shaft for conjoint rotation. The drive unit also has a disconnect clutch, by which a rotor of the first electrical machine for torque transmission is connectable to the output shaft, wherein the rotor of one of the electrical machines is at least indirectly supported radially on the rotor of the other electrical machine by at least one bearing.

Claims

1. A drive unit for a powertrain of an electrically driveable motor vehicle, comprising: a first electrical machine; a second electrical machine; an output shaft, wherein a rotor of the second electrical machine is connected to the output shaft for conjoint rotation; and a disconnect clutch, by which a rotor of the first electrical machine for torque transmission is connectable to the output shaft, wherein a first shaft connected to the rotor of the first electrical machine is supported at one end on a housing wall by a first bearing and supported at an axially opposite end on the output shaft by a second bearing.

2. The drive unit according to claim 1, wherein the output shaft is a hollow shaft, wherein the first shaft is arranged at least in sections radially inside the output shaft.

3. The drive unit according to claim 2, wherein the first shaft is a hollow shaft.

4. The drive unit according to claim 1, wherein the first shaft is supported radially on a radial inner side of the output shaft by the second bearing.

5. The drive unit according to claim 1, wherein the first shaft is designed in one piece.

6. The drive unit according to claim 1, wherein the first shaft has at least one flow channel at least in an axial section, which is radially covered by the rotor of the first electrical machine, configured to discharge coolant from a radial interior of the first shaft to the first electrical machine.

7. A drive assembly with a drive unit according to claim 1 and with an internal combustion engine which is coupleable to the rotor of the first electrical machine for conjoint rotation.

8. A drive unit for a vehicle powertrain, comprising: a housing having a first radial wall, a second radial wall, and a third radial wall; a first electrical machine mounted on the first radial wall by a first bearing and including a first rotor non-rotatably connected to a first shaft, wherein the first electrical machine is arranged axially between the first radial wall and the second radial wall; a second electrical machine supported on the second radial wall and including a second rotor non-rotatably connected to an output shaft, wherein the second electrical machine is arranged axially between the second and third radial walls; and a disconnect clutch arranged in an axial direction between the first electrical machine and the second radial wall of the housing, the disconnect clutch being configured to selectively transfer torque between the first shaft and the output shaft, wherein the first shaft is supported radially on a radial inner side of the output shaft by a second bearing.

9. The drive unit of claim 8, wherein the first shaft forms a radial inner side of the disconnect clutch.

10. The drive unit of claim 9, wherein the output shaft is connected to a radial outer side of the disconnect clutch.

11. The drive unit of claim 8, wherein the second bearing is a needle bearing.

12. The drive unit of claim 8, wherein the second electrical machine is supported on the second radial wall by a third bearing and supported on the third radial wall by a fourth bearing.

13. The drive unit of claim 8, wherein the first shaft includes an axial section radially overlaid by the first rotor defining a flow channel extending axially therethrough and arranged to route cooling fluid from a radial interior of the first shaft to the first electrical machine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The disclosure described above is 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 drawings:

(2) FIG. 1: shows a schematic representation of a drive unit according to the prior art, and

(3) FIG. 2: shows a partial region of a drive unit according to embodiments of the disclosure in sectional view.

DETAILED DESCRIPTION

(4) FIG. 1 has already been discussed in detail to explain the prior art.

(5) FIG. 2 shows a section of a drive unit 100 according to the disclosure for a powertrain of an electrically driveable motor vehicle, in particular a hybrid motor vehicle, which has a first electrical machine 110 and a second electrical machine 120, both of which are arranged on a common axis of rotation 101. The rotor 111 of the first electrical machine 110 is arranged coaxially to the axis of rotation 101 and also to the rotor 121 of the second electrical machine 120. The spaces in which the two electrical machines 110, 120 are arranged are each delimited on both sides in the axial direction by a housing wall 40, 41, 42. Each electrical machine 110, 120 is assigned bearings 1, 3, 4, 5 axially arranged on both sides.

(6) The stator 112 of the first electrical machine 110 and also the stator 122 of the second electrical machine 120 are accommodated in a housing 102 of the drive unit 100.

(7) The rotor 111 of the first electrical machine 110 is connected to a first shaft 130 for conjoint rotation.

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

(9) The first electrical machine 110 is mounted on the outer housing wall 41 by means of the first rotary bearing 1 of the first electrical machine 110. The second electrical machine 120 is supported on the inner housing wall 40 of the housing 102 by a first rotary bearing 3 of the second electrical machine 120 and on the outer housing wall 42 by a second rotary bearing 4 of the second electrical machine 120.

(10) Furthermore, the first shaft 130 is supported radially on the radial inner side 31 of the output shaft 140 by a rotary bearing 5. In contrast to the other rotary bearings 1, 3, 4, the rotary bearing 5 is designed here as a needle bearing and thus requires less radial installation space than the other rotary bearings 1, 3, 4.

(11) The drive unit 100 further comprises a disconnect clutch 150, with which the first electrical machine 110 and thus an internal combustion engine connected to the first shaft 130 rotationally fixed to the rotor 111 of the first electrical machine 110 is connectable or connected to the output shaft 140 for torque transmission. Here, the disconnect clutch 150 is arranged in the axial direction between the first electrical machine 110 and the inner housing wall 40. To secure the axial positions of the disconnect clutch 150 in relation to the output shaft 140, an axial securing element 6 is used here, which is a securing nut shown here in the embodiment, but could also be a securing ring.

(12) In the section of the drive unit 100 shown here, the first shaft 130 is designed in one piece, wherein first shaft 130 is firmly connected to the rotor 111 of the first electrical machine 110.

(13) The first shaft 130 forms the radial inner side 151 of the disconnect clutch 150 or an input element 20 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 or an output element 21 of the disconnect clutch 150, is connected for conjoint rotation to the output shaft 140.

(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 electrical machines 110, 120 are arranged in series, wherein the rotors 111, 121 of the two electrical machines 110, 120 or their axes of rotation are arranged coaxially.

(18) The first shaft 130 is arranged radially inside the output shaft 140, which is configured as a hollow shaft, whereby the overall volume required for the drive unit 100 can be made small.

(19) Furthermore, the first shaft 130 is also designed as a hollow shaft so that it forms a radial interior 51.

(20) An axial section 50 of the first shaft 130, which is radially overlaid by the rotor 111 of the first electrical machine 110, comprises a flow channel 52 which is designed to guide, e.g., cooling fluid from the radial interior 51 of the first shaft 130 to the first electrical machine 110. For this purpose, the flow channel 52 extends in this axial section 50 essentially in the radial direction perpendicular to the axis of rotation 101. In this case, the radial interior space 51 has an appropriate radial extent for the conduction of a sufficient amount of coolant for cooling the first electrical machine 110. Additional holes for supplying the disconnect clutch and/or the second electrical machine with fluid can also be provided. The section of the drive unit 100 shown here can further preferably comprise a transmission (not shown here), which is in operative connection with the output shaft 140 of the drive unit 100, also called transmission input shaft, so that a torque provided by the output shaft 140 or the rotary movement realized by the output shaft 140 can be transmitted via the transmission to another transmission unit of a motor vehicle in a higher or lower ratio, or can be transmitted directly to the drive wheels of a motor vehicle.

(21) The section of a drive unit 100 according to the disclosure shown here can be part of a drive assembly (not shown).

(22) Such a drive assembly is advantageously designed such that, between the internal combustion engine and a first shaft 130 which is connected to the rotor 111 of the first electrical machine 110 for conjoint rotation, a first transmission stage 160 for the purpose of converting the speed of the rotary movement is formed by the internal combustion engine on the first shaft 130.

(23) The first transmission stage 160 is implemented on an external toothing 131 of the first shaft 130.

(24) In this way, a rotary movement generated by the internal combustion engine can be directed via the first transmission stage 160 on the first shaft 130 so that the rotor 111 of the first electrical machine 110 located thereon can be set in rotary movement in order to operate as a generator.

(25) 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 electrical machine 110, to the output shaft 140. Due to the conjointly rotating connection of the rotor 121 of the second electrical machine 120 to the output shaft 140, a torque provided by the second electrical machine 120 can also be applied to the output shaft 140.

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

(27) The rotary movement of the output shaft 140 is directed to the transmission via an external toothing 141 of the output shaft 140, wherein the second transmission stage 161 is realized.

(28) If the represented drive unit 100 according to the disclosure is integrated into a drive assembly, a wide variety of driving conditions can be realized, such as, for example, operation of the internal combustion engine alone to drive a motor vehicle, or also with the addition of the second electrical machine 120 and/or the first electrical machine 110, as well as simultaneous generator operation of the first electrical machine 110 during operation of the internal combustion engine and/or the second electrical machine 120, as well as sole operation of the second electrical machine 120, or also recuperation operation of the first electrical machine 110 and/or the second electrical machine 120.

(29) With the drive unit proposed here, a device is provided which combines a small installation space requirement with low manufacturing costs and low installation effort.

LIST OF REFERENCE NUMBERS

(30) 1 First rotary bearing of the first electrical machine

(31) 2 Second rotary bearing of the first electrical machine

(32) 3 First rotary bearing of the second electrical machine

(33) 4 Second rotary bearing of the second electrical machine

(34) 5 Rotary bearing of the output shaft

(35) 6 Axial securing element

(36) 10 Rotor support of the first electrical machine

(37) 11 Rotor support of the second electrical machine

(38) 20 Input element of the disconnect clutch

(39) 21 Output element of the disconnect clutch

(40) 30 Radial outer side of the first shaft

(41) 31 Radial inner side of the output shaft

(42) 32 Radial outer side of the output shaft

(43) 40 Inner housing wall

(44) 40a Inner housing wall on the first electrical machine

(45) 40b Inner housing wall on the second electrical machine

(46) 41 Outer housing wall on the first electrical machine

(47) 42 Outer housing wall on the second electrical machine

(48) 50 Axial section of the first shaft

(49) 51 Radial interior of the first shaft

(50) 52 Flow channel

(51) 100 Drive unit

(52) 101 Axis of rotation

(53) 102 Housing of the drive unit

(54) 110 First electrical machine

(55) 111 Rotor of the first electrical machine

(56) 112 Stator of the first electrical machine

(57) 120 Second electrical machine

(58) 121 Rotor of the second electrical machine

(59) 122 Stator of the second electrical machine

(60) 130 First shaft

(61) 131 External toothing of the first shaft

(62) 140 Output shaft

(63) 141 External toothing of the output shaft

(64) 150 Disconnect clutch

(65) 151 Radial inner side of the disconnect clutch

(66) 152 Radial outer side of the disconnect clutch

(67) 153 Actuation system

(68) 160 First transmission stage

(69) 161 Second transmission stage