Drive unit, drive assembly and hybrid motor vehicle

Abstract

The drive unit (100) is provided with a first motor (110), a second motor (120), a first shaft (130) and an output shaft (140), wherein a rotor (111) of the first motor (110) is rotationally fixed to the first shaft (130), and a rotor (121) of the second motor (120) is rotationally fixed to the output shaft (140), and the drive unit (100) further comprises a separation clutch (150), wherein the drive unit (100) further comprises a connecting element (230) for rotationally fixedly connecting the internal combustion engine, and a first gear ratio step (142) with a gear ratio i<1 is arranged between the connecting element (230) and the shafts (130, 140), and wherein the drive unit (100) has an electromechanical parking lock unit (1), by which the rotational movement of the output end of the first gear ratio step (142) can be prevented.

Description

Technical Field

[0001] The invention relates to a drive unit for a drive train of an electrically drivable motor vehicle, in particular a hybrid motor vehicle, and to a drive assembly having a drive unit according to the invention and a hybrid motor vehicle having a drive assembly according to the invention. Background Art

[0002] Drive devices for hybrid vehicles are known from the prior art and include, in particular, an internal combustion engine, a first electric machine and a second electric machine.

[0003] DE 10 2015 222 690 A1, DE 10 2015 222 691 A1 and WO 2017 084 887 A1 describe methods for controlling such a drive device, wherein the drive device can be operated in a plurality of operating modes.

[0004] DE 10 2015 222 690 A1 describes a series hybrid operation in which the traction drive torque is achieved by means of a second electric machine and the internal combustion engine drives the first electric machine to generate electrical energy. The operation of the internal combustion engine at an operating point is described, in which the combined efficiency of the drive depends on the efficiency of the internal combustion engine and the efficiency of the first electric machine.

[0005] Documents DE 10 2015 222 691 A1 and WO 2017 084 887 A1 describe a performance-oriented mode and a consumption-oriented mode, each of which is condition-dependent. The condition comprises that the target drive value is increased to an intermediate value between an internal combustion engine threshold representing a maximum drive value in a parallel hybrid mode (in which only the internal combustion engine generates traction drive torque) and a parallel hybrid mode threshold representing a maximum drive value in a parallel boost hybrid mode.

[0006] DE 10 2015 222 692 A1, WO 2017 084 888 A1, DE 10 2015 222 694 A1 and WO 2017 084 889 A1 describe a method for operating a drive device of a hybrid vehicle for driving drive wheels, wherein the drive device comprises an internal combustion engine, a first electric machine coupled to the internal combustion engine, a second electric machine, a battery and a main clutch between the internal combustion engine and the drive wheels.

[0007] DE 10 2015 222 692 A1 and WO 2017 084 888 A1 describe a drive device operating in one of three operating modes, namely pure electric operation, series hybrid operation or parallel hybrid operation, wherein the traction drive torque provided during the change from the first operating mode to the second operating mode corresponds to a progression of appropriate selection between the traction drive torque provided before and after the change.

[0008] DE 10 2015 222 694 A1 and WO 2017 084 889 A1 disclose that a transmission is also arranged between the internal combustion engine and the drive wheels.

[0009] Furthermore, the cited corresponding document describes a hybrid vehicle having a hybrid drive.

[0010] The hybrid vehicle repeatedly described in the prior art includes an internal combustion engine, a first motor and a second motor, at least one drive wheel and a main clutch and a first clutch and a second clutch. The main clutch is arranged between the internal combustion engine and the drive wheel, the first clutch is arranged between the first motor and the output shaft of the internal combustion engine, and the second clutch is arranged between the second motor and the drive wheel.

[0011] From DE 10 2017 128 289.0 (not yet published) a drive unit for a drive train of a hybrid motor vehicle is known, the drive unit having an internal combustion engine, a first electric machine, a second electric machine, a first gear ratio step and a drive shaft of the first electric machine and / or the second electric machine. In addition, the drive unit comprises a transmission subunit, by means of which the drive shaft of the respective electric machine is coupled or can be coupled to a wheel drive shaft. The second gear ratio step is coupled to a countershaft unit, wherein the countershaft unit has an integrated clutch and is further connected to the wheel drive shaft, so that the internal combustion engine can be coupled to the wheel drive shaft via the second gear ratio step, depending on the position of the clutch.

[0012] DE 10 2017 127 695.5, which has not yet been published, discloses a powertrain for a hybrid motor vehicle, which comprises a transmission input shaft, which is operatively connected to a first electric machine and an internal combustion engine via a first partial powertrain for transmitting torque, and is operatively connected to a second electric machine via a second partial powertrain for transmitting torque. The second electric machine is permanently connected to the transmission input shaft in a torque-transmitting manner, and the first electric machine and the internal combustion engine can be connected to the transmission input shaft in a connectable manner for transmitting torque. The first electric machine and / or the second electric machine can thus be designed to be cooled. It is particularly preferred that the cooling is carried out by means of water cooling of the vehicle cooling circuit or by means of oil cooling of the transmission oil from the transmission. In addition, the separating clutch used can also be designed as an oil-cooled multi-plate clutch. Summary of the invention

[0013] Starting from this point, it is an object of the present invention to provide a drive unit and a drive assembly equipped with the drive unit and a hybrid motor vehicle equipped with the drive assembly, which ensure efficient operation with efficient use of the installation space.

[0014] This object is achieved by a drive unit according to the invention as claimed in claim 1. Advantageous embodiments of the drive unit are listed in the dependent claims 2 to 8. In addition, according to claim 9, a drive assembly for a motor vehicle with a drive unit is provided, and according to claim 10, a hybrid motor vehicle with a drive assembly according to the invention is provided.

[0015] Features of the claims, including features of the explanation given in the following description and of the drawings, may be combined in any technically reasonable way, including additional embodiments of the invention.

[0016] The invention relates to a drive unit for a powertrain of an electrically drivable motor vehicle, in particular a hybrid motor vehicle, the drive unit having a first electric machine and a second electric machine and a first shaft and an output shaft, which can also be referred to as a transmission input shaft. The rotor of the first electric machine is rotationally fixed to the first shaft and the rotor of the second electric machine is rotationally fixed to the output shaft.

[0017] Furthermore, the drive unit comprises a disconnect clutch, with which the rotor of the first electric machine and therefore the internal combustion engine connected to the first shaft for torque transmission can be connected or connected to the output shaft.

[0018] In addition, the drive unit further comprises a connecting element, which is part of an output element of the internal combustion engine. The connecting element is used for rotationally fixed connection to the internal combustion engine, whereby a first gear ratio step with a gear ratio i<1 is arranged between the connecting element and a shaft rotationally fixed to the rotor of the electric machine, for transferring the speed achieved by the internal combustion engine to the shaft at a step-up ratio. In addition, the drive unit comprises an electromechanical parking lock unit, which is arranged and configured such that a rotational movement of the output end of the first gear ratio step can be blocked.

[0019] In particular, it can be provided that the two electric machines are arranged in series. In a preferred embodiment, it can be provided that the rotors of the two electric machines or their axes of rotation are arranged coaxially.

[0020] The disconnect clutch is a switchable clutch which can be switched from an open state to a closed state and vice versa. In particular, it can be provided that the disconnect clutch is closed in a normal state so that the first shaft and the output shaft are rotationally fixed to each other.

[0021] The drive unit may be designed such that the first shaft fixedly connected to the rotor of the first electric machine is arranged radially inside the output shaft fixedly connected to the rotor of the second electric machine.

[0022] The first shaft can be designed split, ie in the form of a central hollow shaft, on which a rotationally fixed hub is arranged in certain regions, which hub in turn is rotationally fixed to the rotor of the first electrical machine.

[0023] A radially inner side of the disconnect clutch may be rotationally fixed to a hub on the first electric machine, and a radially outer side of the disconnect clutch may be connected to an output shaft rotationally fixed to a rotor of the second electric machine.

[0024] The output of the first gear ratio step is correspondingly defined by the first shaft or individual elements forming the first shaft or being connected to the first shaft in a rotationally fixed manner, such as a hollow shaft, a hub, a rotor of the first electric machine and a disconnect clutch, by means of which the output shaft is connected to the first shaft. According to the invention, it can be provided that when the parking lock unit is actuated, it has a blocking effect on at least one of these elements.

[0025] Since the output of the first gear ratio step rotates at a higher speed than the connected internal combustion engine or the connecting element for the rotationally fixed connection to the internal combustion engine, the output of the first gear ratio step has a lower torque than the connecting element. This makes it possible to reduce the wear of the parking lock unit, because it has to exert or overcome lower forces to cause a rotational blockage on the first shaft.

[0026] The rotational blocking may be designed such that a small amount of rotation angle, for example up to 2°, may still be achieved through the shaft while producing a blocking effect.

[0027] The connecting element preferably comprises an internally toothed gear, wherein the first shaft has external teeth, and the two teeth mesh with each other for transmitting the rotational movement from the connecting element to the first shaft. The external teeth can be an integral part of the first shaft, in particular a hollow shaft thereof, or can be formed by another machine element which is rotationally fixed to the first shaft.

[0028] Advantageously, the output shaft further comprises a locking tooth for positive engagement of a locking element of the electromechanical parking lock unit. It can therefore be provided that the electromechanical parking lock unit acts on the output shaft, which therefore also blocks the rotational movement of the first shaft when the separating clutch is closed.

[0029] The connecting element can be a component of an output element of the internal combustion engine to be connected, which output element in particular comprises a damper unit.

[0030] Furthermore, the output element can have a further clutch for opening and closing the torque transmission path between the internal combustion engine and the drive unit, or a combination of a damper unit and a clutch.

[0031] In a further advantageous embodiment of the drive unit, provision can be made for the drive unit to have a second gear ratio step which is formed by teeth, in particular external teeth, of the output shaft and a first gear meshing with the teeth of the output shaft.

[0032] This results in a speed ratio of i>1 of the output shaft and thus slows down the electromechanical parking lock unit so that the entire transmission formed by the first gear ratio step and the second gear ratio step is carried out at a point of the adjoining torque transmission path of maximum speed and minimum torque.

[0033] The output shaft can itself form the teeth or can be connected to the teeth in a rotationally fixed manner.

[0034] Therefore, the transmission is designed as an integral part of the drive unit, which is operatively connected to the output shaft of the drive unit (also called the transmission input shaft) so that the torque provided by the output shaft or the rotational movement achieved by the output shaft can be transmitted via the transmission to another transmission unit of the motor vehicle or can be transmitted directly to the drive wheels of the motor vehicle.

[0035] The transmission can include a differential transmission in the output region, or can be designed as such.

[0036] The first gear can be coupled in a rotationally fixed manner to a layshaft of the transmission, the external teeth of which in turn mesh with an input gear of the differential transmission, so that a third gear ratio step is achieved.

[0037] Geometrically, the units of the drive unit are preferably arranged in such a way that the engagement of the electromechanical parking lock unit at the output of the first gear ratio step takes place in the axial direction between the position of the separating clutch and the first gear ratio step.

[0038] In an advantageous embodiment, the locking tooth of the output shaft is positioned directly adjacent to the tooth for forming the second gear ratio step in the axial direction. On the side axially opposite to the tooth for forming the second gear ratio step, an external tooth for forming the first gear ratio step is arranged on the first shaft.

[0039] The drive unit can furthermore have a master control device for controlling the electromechanical parking lock unit. The master control device preferably has an interface for connection to a central control unit of a motor vehicle to be equipped with the drive unit.

[0040] Another aspect of the invention is a drive assembly having a drive unit according to the invention and having an internal combustion engine, which is connected or can be connected to the rotor of the first electric machine in a rotationally fixed manner via a connecting element of an output element of the internal combustion engine. In another embodiment, the drive assembly also includes at least one wheel drive shaft, which is connected to the output shaft of the drive unit via a transmission, so that the rotational movement achieved by the output shaft can be transmitted to the wheel drive shaft via the transmission.

[0041] To achieve this object, a hybrid motor vehicle is also provided with a drive assembly according to the invention and a central control unit which is connected to a main control device of the drive unit by an interface in terms of control technology. In this way, the electromechanical parking lock unit can be controlled by the central control unit via the main control device of the drive unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The invention described above is described in detail below based on the relevant technical background and with reference to the associated drawings showing preferred embodiments. The invention is in no way limited by the purely schematic drawings, wherein it should be pointed out that the embodiments shown in the drawings are not limited to the dimensions shown. In the drawings:

[0043] Figure 1 : shows a cross-sectional view of a drive unit according to the present invention, and

[0044] Figure 2 : shows a perspective view of an electromechanical parking lock unit. DETAILED DESCRIPTION

[0045] Figure 1 A drive unit 100 according to the invention for a powertrain of an electrically drivable motor vehicle, in particular a hybrid motor vehicle, is shown, which has a first electric machine 110 and a second electric machine 120, both of which are arranged on a common rotation axis 101. A rotor 111 of the first electric machine 110 is arranged coaxially with the rotation axis 101 and also coaxially with a rotor 121 of the second electric machine 120.

[0046] The stator 112 of the first motor 110 and the stator 122 of the second motor 120 are housed in the housing 102 of the drive unit 100. The rotor 111 of the first motor is connected in a rotationally fixed manner to the first shaft 130. The rotor 121 of the second motor 120 is rotationally fixed to an output shaft 140, which may also be referred to as a transmission input shaft.

[0047] The drive unit 100 further comprises a disconnect clutch 150 , by means of which the first electrical machine 110 and therefore the internal combustion engine connected to a first shaft 130 rotationally fixed to the rotor 111 of the first electrical machine 110 can be connected or connected to the output shaft 140 for torque transmission.

[0048] In the embodiment shown here, the first shaft 130 is designed in two parts, namely consisting of a central hollow shaft 132 and a hub 133 which is positioned on the hollow shaft 132 and connected thereto in a rotationally fixed manner, wherein the hub 133 is in turn connected to the rotor 111 of the first electric machine 110 .

[0049] The hub 133 forms a radial inner side 151 of the disconnect clutch 150 , or is firmly connected to the input side of the disconnect clutch 150 .

[0050] A radially 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 in a rotationally fixed manner.

[0051] The disconnect clutch 150 is a switchable clutch which 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 .

[0052] In this manner, when the disconnect clutch 150 is closed, torque may be transferred from the first shaft 130 to the output shaft 140 , and vice versa.

[0053] Thus, in the embodiment shown here, it can be provided that the two motors 110, 120 are arranged in series, wherein the rotors 111, 121 of the two motors 110, 120 or their axes of rotation are arranged coaxially. The first shaft 130 or its central hollow shaft 132 runs radially inside the output shaft 140, thereby reducing the overall volume required for the drive unit 100.

[0054] In addition, the drive unit 100 shown here includes a transmission 160, which is operatively connected to the output shaft 140 (also referred to as the transmission input shaft) of the drive unit 100, so that the torque provided by the output shaft 140 or the rotational movement achieved by the output shaft 140 can be transmitted to or reduced by another transmission unit of the motor vehicle via the transmission 160, or can be directly transmitted to the drive wheels of the motor vehicle.

[0055] In the embodiment shown here, the transmission 160 comprises a differential transmission 170. Furthermore, the transmission 160 comprises a first gear wheel 161, which meshes with an external toothing 141 on the output shaft 140. Thus, a second gear ratio step 162 is achieved in the drive unit 100 by means of the first gear wheel 161. Thereby, the first gear wheel 161 is coupled in a rotationally fixed manner to a layshaft 163 of the transmission 160, whose external toothing 164 in turn meshes with an input gear wheel 171 of the differential transmission 170, so that a third gear ratio step 172 is achieved.

[0056] The drive unit 100 is part of the likewise shown exemplary embodiment of a drive arrangement 200 according to the invention.

[0057] The drive assembly 200 further comprises an internal combustion engine (not shown here) which, when the connecting element 210 shown is connected, is coupled or can be coupled in a rotationally fixed manner to the rotor 111 of the first electric machine 110 via the first shaft 130 by means of the insertion of a further clutch.

[0058] The drive assembly 200 shown is designed so that a first gear ratio step 142 is formed between a connecting member 210 for an internal combustion engine (not shown here) and a first shaft 130 to which the rotor 111 of the first electric machine 110 is rotationally fixed, for converting the rotational speed of the rotational movement achieved by the internal combustion engine or its connecting member 210 to the first shaft 130.

[0059] 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 a torque transmission path between the internal combustion engine and the drive unit 100, or a combination of the damper unit 221 and the clutch 222 shown.

[0060] Furthermore, the output element 220 comprises as a component an internally toothed gear 223 which meshes with the external toothing 131 of the first shaft 130 and thus realizes a first gear ratio step 142 .

[0061] It can be seen that in the exemplary embodiment shown here, the rotation axis of the output element 220 is laterally offset relative to the rotation axis 101 of the drive unit 100 .

[0062] In this way, the rotational movement generated by the internal combustion engine (not shown here) can be directed to the first shaft 130 via the output element 220 and the first gear ratio step 142, so that the rotor 111 of the first electric machine 110 located on the first gear ratio step can be set to rotational movement in order to operate as a generator.

[0063] When the disconnect clutch 150 is closed, the applied rotational movement can be transmitted from the first shaft 130 to the output shaft 140, which first shaft may be enhanced by the motor drive of the first electric machine 110. Since the rotor 122 of the second electric machine 120 is rotationally fixedly connected to the output shaft 140, the torque provided by the second electric machine 120 can also be applied to the output shaft 140.

[0064] Alternatively, when the disconnect clutch 150 is open, only the second motor 120 can be operated alone to rotate the output shaft 140 .

[0065] The rotational movement of the output shaft 140 is guided via its external toothing 141 to the first gear 161 of the connected transmission 160 , wherein a second gear ratio step 162 is realized.

[0066] The torque or rotational movement is transmitted from the first gear 161 to the layshaft 163 , from which it is fed to the differential transmission 170 via the input gear 171 .

[0067] Torque is fed from the differential transmission 170 to a wheel drive shaft (not shown here), or to another transmission as required for increasing or decreasing torque or speed.

[0068] exist Figure 1 It can also be seen in FIG. 2 that the drive unit 200 shown comprises an electromechanical parking lock unit 1 which engages with a locking element 3 in a locking tooth 2 of the output shaft 140 .

[0069] The drive assembly 200 shown can be used to achieve multiple driving states, such as: operating the internal combustion engine alone to drive the motor vehicle, or operating the internal combustion engine to drive the motor vehicle when the second motor and / or the first motor are also connected; and simultaneous generator operation of the first motor during operation of the internal combustion engine and / or the second motor; and operating the second motor alone, or also regenerative operation of the first motor and / or the second motor.

[0070] The electromechanical parking lock unit 1 provided according to the invention can prevent a rotational movement of the output shaft 140 and thus can prevent the wheels of a vehicle equipped with a drive unit according to the invention from being driven.

[0071] The connecting element 230 for connecting the output element 220 of the internal combustion engine (not shown here) is obviously designed with a larger diameter than the external toothing 131 of the first shaft 130, so that the first gear ratio step 142 achieved thereby increases the speed of the output element 220. In a corresponding manner, the torque applied to the first shaft 130 is relatively low, so that the electromechanical parking lock unit 1 engaged here has to overcome or maintain a relatively low torque.

[0072] exist Figure 2In FIG. 1 , a perspective view of an electromechanical parking lock unit 1 is shown. In detail, a locking element 3 is shown here as an element of the electromechanical parking lock unit 1 , which can be actuated such that, as in FIG. Figure 2 As can be seen in FIG. 1 , the locking element can engage in the locking tooth 2 or in the output shaft 140. Thus, a rotation of the output shaft 140 is prevented. In a corresponding manner, a rotational movement of the output end 143 of the first gear ratio step 142 is prevented.

[0073] Thus, a rotational movement of the first gear wheel 161 located on the layshaft 163 is blocked. In this regard, a rotational movement of the external toothing 164 arranged in a rotationally fixed manner is also blocked.

[0074] Since the input gear 171 of the differential transmission 170 meshes in the external toothing 164 of the countershaft 163 , the differential transmission 170 is accordingly blocked.

[0075] In this way, the electromechanical parking lock unit 1 can block a rotational movement of the wheels of the motor vehicle connected to the differential transmission 170 and can implement a parking lock.

[0076] With the drive unit proposed here and a drive assembly equipped with the drive unit and a hybrid motor vehicle equipped with the drive assembly, means are provided which ensure efficient operation with efficient use of the installation space.

[0077] Description of Reference Numerals

[0078] 1 Electromechanical parking lock unit 2 Locking tooth (of output shaft) 3 Locking element (of parking lock unit) 100 Drive unit 101 Rotation axis 102 Housing 110 First electric machine 111 Rotor of first electric machine 112 Stator of first electric machine 120 Second electric machine 121 Rotor of second electric machine 122 Stator of second electric machine 130 First shaft 131 External toothing of first shaft 132 Central hollow shaft 133 Hub 140 Output shaft 141 External toothing of output shaft 142 First gear ratio step 143 First toothing Output end of the gear ratio step 150 disconnecting clutch 151 radial inner side 152 radial outer side 153 disconnecting clutch actuating system 160 transmission 161 first gear 162 second gear ratio step 163 layshaft 164 external teeth of the layshaft 170 differential transmission 171 input gear 172 third gear ratio step 200 drive assembly 210 connecting part for the internal combustion engine 220 output element 221 damper unit 222 clutch 223 internal gear 230 connecting element.

Claims

1. A drive unit (100) for a powertrain of an electrically drivable motor vehicle, the drive unit having a first motor (110) and a second motor (120) as well as a first shaft (130) and an output shaft (140), wherein a rotor (111) of the first motor (110) is rotationally fixed to the first shaft (130) and a rotor (121) of the second motor (120) is rotationally fixed to the output shaft (140), and the drive unit (100) further comprises a disconnect clutch (150), by means of which the rotor (111) of the first motor (110) can be connected or connected to the output shaft (140) for torque transmission, wherein the drive unit (100) further comprises a connecting element (230) for rotationally fixed connection to an internal combustion engine, and a first gear ratio step (142) with a gear ratio i<1 is arranged between the connecting element (230) and the first shaft (130), characterized in that The drive unit (100) has an electromechanical parking lock unit (1) which is arranged and configured in such a way that a rotational movement of the output end of the first gear ratio step (142) can be prevented; The output shaft (140) has a locking tooth (2) for forced engagement of a locking element of the electromechanical parking lock unit (1); The engagement of the electromechanical parking lock unit (1) at the output end of the first gear ratio step (142) is achieved in the axial direction between the position of the separation clutch (150) and the first gear ratio step (142); The locking tooth (2) of the output shaft (140) is positioned adjacent to the tooth (141) of the output shaft (140) along the axial direction, and the tooth (141) of the output shaft (140) is used to form a second gear ratio step (162).

2. The drive unit according to claim 1, characterized in that: The connecting element (230) comprises an internal gear (223), and the first shaft (130) has external teeth (131), wherein the internal gear (223) and the external teeth (131) mesh together for transmitting the rotational movement from the connecting element (230) to the first shaft (130).

3. A drive unit according to any one of the preceding claims 1 to 2, characterized in that: The connecting element (230) is part of an output element (220) of an internal combustion engine to be connected.

4. The drive unit according to claim 3, characterized in that: The output element includes a damper unit (221).

5. The drive unit according to any one of the preceding claims 1 to 2, characterized in that: The drive unit has a second gear ratio step (162), which is formed by the teeth (141) of the output shaft (140) and a first gear (161) meshing with the teeth (141) of the output shaft (140), and the speed gear ratio of the output shaft (140) is greater than 1 in such a way that the electromechanical parking lock unit (1) performs a complete transmission formed by the first gear ratio step (142) and the second gear ratio step (162) at a point in the torque transmission path where the maximum speed and the minimum torque are adjacent.

6. A drive unit according to any one of the preceding claims 1 to 2, characterized in that: The drive unit (100) comprises a main control device for controlling the electromechanical parking lock unit (1).

7. A drive assembly having a drive unit according to any one of claims 1 to 6 and having an internal combustion engine, wherein the internal combustion engine is connected or can be connected to the rotor (111) of the first electric machine (110) in a rotationally fixed manner via a connecting element (230) of an output element (220) of the internal combustion engine.

8. A hybrid motor vehicle comprising a drive assembly according to claim 7 and a central control unit which is connected in terms of control technology via an interface to a main control device of the drive unit.

Images