Electric drive unit with parking wheel arrangement

Abstract

Electric drive unit, comprising: a first electric machine which is rotationally coupled to a first drive wheel via a first transmission; a second electric machine which is rotationally coupled to a second drive wheel via a second transmission; a separating clutch that is set up: in an engaged configuration, to rotatably couple the first electric machine and the second electric machine; and in a disengaged configuration, to rotationally decouple the first electric machine and the second electric machine; and a parking lock assembly coupled to the first transmission or the second transmission and configured to prevent rotation of the respective transmission.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an electric drive unit for a powertrain. In particular, the disclosure relates to an electric drive unit having a plurality of electric machines and a parking lock assembly. BACKGROUND AND SUMMARY

[0002] Electric drivetrains are being used in certain vehicles as the transportation sector moves toward powertrain electrification. Some electric drivetrains include two motors that propel the vehicle. Certain electric drivetrains use a dual-motor architecture, where the motors independently provide power to the drive wheels. Some electric drivetrains employ parking locks to prevent the vehicle from moving.

[0003] US 11,192,436 B1 to Puiu et al. discloses an electric drive unit with two motors mounted on a differential connected to the front and rear drive wheels. In Puiu's system, a parking gear is mounted on the differential to provide a parking lock.

[0004] The inventors have identified several disadvantages of Puiu's Park Lock System and other park lock systems. Puiu's park lock is limited to use in four-wheel drive vehicles. Furthermore, the torque of Puiu's park gear, when engaged, may be higher than desirable in certain powertrain architectures. Other electric powertrains utilize two drive units that independently drive opposing drive wheels. In some of these dual electric drive architectures, two park locks are used. However, using two park locks may result in wheel spin until the park gears and pawls find their position to engage the left and right drive units. Using two park locks may require additional control methods and processing resources, further increasing system complexity.

[0005] In view of the above-mentioned problems, the inventors have developed an electric drive unit to at least partially solve these problems. In one example, the electric drive unit comprises a first electric machine rotationally coupled to a first drive wheel via a first transmission. The electric drive unit also comprises a second electric machine rotationally coupled to a second drive wheel via a second transmission. The electric drive unit further comprises a disconnect clutch and a parking lock assembly. The disconnect clutch selectively rotationally couples the first and second electric machines, and the parking lock assembly is coupled to one of the first and second transmissions and configured to prevent rotation of the corresponding transmission.This allows a single parking lock assembly to be used to prevent movement of the opposing drive wheels, reducing unit complexity and package space, if desired, compared to electric drives that utilize multiple parking lock devices. Furthermore, the disconnect clutch allows for improved traction of the electric drive unit, thereby increasing the electric drive unit's appeal to customers.

[0006] In another example, the electric drive unit may additionally include a controller that includes instructions that, when executed during a zero-speed condition, cause the controller to engage the disconnect clutch and activate the parking lock assembly. In this way, the parking lock assembly may be effectively engaged using a controller that is less complex than the control strategies used in electric drives that utilize multiple parking locks.

[0007] It should be understood that the above summary is intended to introduce, in simplified form, a selection of concepts that are further explained in the detailed description. It is not intended to identify the most important or essential features of the claimed subject matter, the scope of which is clearly defined by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that address the disadvantages noted above or elsewhere in this disclosure. SHORT DESCRIPTION OF THE CHARACTERS Fig. 1 shows a schematic representation of an electric drive train in a vehicle. Fig. 2 to 4 show various example architectures of electric drive units with multiple electric machines. Fig. 5 shows a table showing different operating modes for the Fig. 2-4 shows the electric drive units. Fig. 6 shows a method for operating an electric drive unit. Fig. 7 shows a timing diagram relating to an exemplary control scheme for an electric drive unit. DETAILED DESCRIPTION

[0008] This article describes a multi-motor electric drive unit that provides efficient parking lock functionality and improved traction performance. To achieve these capabilities, the electric drive unit includes a disconnect clutch that selectively couples two traction motors rotationally coupled to separate drive wheels via transmissions. The disconnect clutch can be engaged to increase traction performance (e.g., on steep inclines, in terrain with lower traction, etc.) and disengaged when wheel speed differentiation is desired (e.g., when cornering). This allows the electric drive unit to exhibit torque vectoring capability under certain conditions and deliver higher power under other conditions, such as when climbing hills, encountering terrain with variable traction (e.g., rocky, sandy, and / or muddy terrain), and the like.A parking lock assembly is located in one of the electric drive unit's gearboxes. To mechanically lock the electric drive unit, the parking lock assembly and the disconnect clutch are engaged together. This allows a single parking lock assembly to lock the opposite drive wheels, if desired. Consequently, the use of duplicate parking locks can be avoided, and the package efficiency and complexity of the electric axle are reduced by eliminating redundant parking locks and the control strategy for both parking locks, if desired.

[0009] Fig. 1 shows a schematic representation of an electric vehicle (EV) 100. The vehicle may be a passenger car, a commercial vehicle, a road vehicle, or an off-road vehicle, with various examples.

[0010] The electric vehicle 100 has a powertrain 102 that includes an electric drive unit 104 (e.g., an electric axle). The EV may be a pure electric vehicle (e.g., a battery electric vehicle (BEV)) in one example, or a hybrid electric vehicle (HEV) with an internal combustion engine in another example. In the HEV example, an axle driven by an internal combustion engine may be used in the vehicle and / or the internal combustion engine may be used to charge one or more traction energy storage devices 105 (e.g., one or more traction batteries, capacitors, and the like).

[0011] The electric drive unit 104 comprises a first electric machine 106 and a second electric machine 108. These electric machines 106, 108 can, in particular, be traction motors. The electric machines can be multi-phase alternating current (AC) machines. In other examples, however, the electric machines can also be direct current (DC) machines.

[0012] In the illustrated example, a first inverter 110 and a second inverter 112 are electrically coupled to the first electric machine 106 and the second electric machine 108. The inverters 110, 112 convert direct current to alternating current and vice versa. However, in alternative examples, one inverter may be used to power both electric machines, or the inverters may be omitted if DC electric machines are used in the powertrain.

[0013] The inverters 110, 112 may receive electrical energy from one or more energy storage devices 105 (e.g., traction batteries, capacitors, fuel cells, combinations thereof, and the like). Arrows 114 indicate the electrical energy transfer between the electric machines 106, 108, the inverters 110, 112, and the energy storage device(s) 105, which may occur during the various operating modes of the system. In one example, the inverters 110, 112 may each be electrically connected to one or more energy storage devices. However, in other examples, the inverters 110, 112 may also be electrically connected to other energy storage devices.

[0014] The first and second electric machines 106, 108 are rotationally coupled to a first transmission 116 and a second transmission 118, respectively. The first and second transmissions are in Fig. 1. The transmissions 116, 118 are in turn rotationally coupled to the drive wheels 120 and 122, respectively. Each of the transmissions 116, 118 may include one or more gears, shafts, and / or other mechanical components for transmitting the mechanical power from the respective electric machine to the corresponding drive wheel.

[0015] A disconnect clutch 124 is also included in the electric drive unit 104. The disconnect clutch 124 is configured to selectively rotationally couple the first electric machine 106 and the second electric machine 108. In this way, torque can be selectively transferred between the electric machines 106, 108. Furthermore, a parking lock assembly 126 (shown schematically in Fig. 1). The parking lock assembly 126 includes a park gear and a park gear engagement device that prevents rotational movement of the park gear in the engaged state. In the illustrated example, the parking lock assembly 126 is disposed within the electric machines 106, 108. However, the parking lock assembly 126 may also be positioned at other suitable locations, as explained in more detail herein. In the Fig. In the example shown in Figure 1, the electrical machines, gearbox, separating clutch, parking lock assembly and drive wheels are generally arranged coaxially. However, other arrangements are also possible, which are explained here with regard to the Fig. 2-4 will be explained in more detail.

[0016] It is understood that the arrangement of the electric machines 106, 108, the transmissions 116, 118, the separating clutch 124 and the parking lock arrangement 126 is more complex than it is shown in the schematic representation of the electric drive unit 104 in Fig. 1. Various possible architectures of electric drive units, as shown in the Fig. 2-4 and discussed in more detail herein.

[0017] The EV 100 may also include a control system 190 with a controller 191, as shown in Fig. 1. The controller 191 may include a microcomputer with components such as a processor 192 (e.g., a microprocessor unit), input / output ports, an electronic storage medium 194 for executable programs and calibration values ​​(e.g., a read-only memory chip, read-only memory, diagnostic memory, a data bus, and the like). The storage medium may be programmed with computer-readable data representing instructions executable by the processor to perform the methods and control techniques described herein, as well as other variations that are expected but not explicitly listed. Thus, the control techniques, schemes, methods, and the like described herein may be stored as instructions in non-volatile memory.

[0018] The controller 191 may receive various signals from sensors 195 connected to various areas of the vehicle 100. Sensors 195 may include, for example, a pedal position sensor for detecting the actuation of a driver-operated pedal such as an accelerator and / or brake pedal, a drive mode selection sensor, clutch position sensors, speed sensors, electric machine speed sensors, an ambient temperature sensor, an ambient pressure sensor, and the like. The clutch position sensors may be coupled to the clutches, each of which provides a signal indicating the clutch state (e.g., engaged or disengaged).

[0019] An input device 198 (e.g., accelerator pedal, brake pedal, drive mode selector, combinations thereof, and the like) may also provide input signals indicating the driver's intent for system control. For example, the input device may include a drive mode selector that allows the operator to select a drive mode (e.g., forward or reverse drive mode) or a park mode. For example, the input device may send a signal to the controller indicating the operator's intent for the current operating mode of the electric drive unit (e.g., park or drive).

[0020] After receiving the signals from the various sensors 195 from Fig. 1, the controller 191 processes the received signals and deploys various actuators 196 of system components to adjust the components based on the received signals and the instructions stored in the memory of the controller 191. For example, the controller 191 may adjust the speed of the electric machine 106, such as by adjusting the inverter 110. The controller 191 may, for example, determine that the speed of the electric machine should be adjusted, and in response to such a determination, the controller may send a command to the inverter to adjust the speed of the electric machine. The other controllable components (e.g., the disconnect clutch 124, the parking lock assembly 126, etc.) in the system may function in a similar manner, e.g., with respect to sensor signals, control commands, and actuator adjustment.The control system 190 with the controller 191 can also be used in the other electric drive units described herein. Furthermore, the controller can be used to execute the methods, control schemes, and the like described herein via instructions stored in memory and executable by a processor.

[0021] Fig. 1-4 contain a coordinate system for orienting the views. In one example, the z-axis can be a vertical axis (e.g., parallel to a gravitational axis), the y-axis can be a longitudinal axis (e.g., a horizontal axis), and / or the x-axis can be a lateral axis. However, in other examples, the axes can have different orientations.

[0022] Fig. 2 shows a more detailed example of an electric drive unit 200. The electric drive unit 200 is specifically illustrated as an electric drive axle, in which the electric machines, transmissions, and associated components form an integrated axle assembly. However, in other examples, the electric machines or other components in the drive unit may be spaced from the drive axle assembly. Fig. The electric drive unit 200 shown in Figure 2 may have structural and / or functional features of the Fig. 1 and one or more of the other electric drive units described herein, and vice versa.

[0023] In the example of the electric drive axle, the drive axle may in particular be an electric beam axle. A live axle is an axle with mechanical components that structurally support one another and that extend between drive wheels. For example, in one embodiment, the live axle may be a structurally continuous structure that extends between the drive wheels on a transverse axis. In this way, wheels coupled to the live axle move substantially in unison when the vehicle travels, for example, on uneven road surfaces. More specifically, the camber angle of the wheels may remain substantially constant while the suspension moves during travel. The live axle, in one example, may be connected to a dependent suspension 202 (shown schematically in Fig. 2). Therefore, the electric axle can represent an unsprung mass.

[0024] The electric drive unit 200, in turn, includes a first electric machine 204 and a second electric machine 206. Each of the electric machines includes a rotor 208 with a rotor shaft 210 and a stator 212, which may include end windings 214. The electric machines 204, 206 are similar in size and construction in the example shown. The electric machines 204, 206 may be similarly constructed except for the arrangement of the internal components of the stator and rotor to achieve the design goals and keep the left and right shafts on the same axis.

[0025] In the example shown, a separating clutch 216 is arranged axially between the inner sides 218 of the electric machines 204, 206. Specifically, the rotor shaft extensions 220, 221 of the electric machines 204, 206 are rotationally coupled to the opposing engaging components 222, 223 in the separating clutch 216. The engageable parts can be toothed surfaces of the clutch, disk carriers and / or drums, etc. Thus, the separating clutch 216 can be a dog clutch, a synchronizer, or a friction clutch (e.g., a wet friction clutch).The disconnect clutch 216 may also be an electromagnetically actuated clutch configured to adjust shaft speed during clutch engagement and disengagement via a control scheme that enables smooth operation of the clutch engagement and disengagement function, thereby reducing the likelihood of improper engagement and clutch degradation. The rotor shaft extensions 220, 221, and the other rotor shaft extensions described herein may be removably or fixedly coupled or connected to the rotor shafts.

[0026] The transmissions 224 and 226 are rotationally coupled to the electric machines 204 and 206, respectively. The transmissions are similar in size and construction to the example shown. However, in other examples, transmissions of different sizes and / or designs may be used. The transmission 224 includes a gear 228 that is fixedly connected to a rotor shaft extension 230 so that it rotates therewith. The gear 228 meshes with a gear 232 that is rotationally coupled to an intermediate shaft 234. The gears 228 and 232 form a first stage. In the illustrated example, the transmission 224 (as well as the transmission 226) includes two stages. However, it should be understood that the transmissions may include a single stage or more than two stages in other embodiments. The number of gear stages may be selected depending on the size and construction of the electric machines, the vehicle weight, the vehicle's performance goals, etc.

[0027] In the example shown, the transmissions 224, 226 are depicted as single-speed transmissions, which can reduce the complexity and size of the transmissions compared to multi-speed transmissions. However, in other examples, the transmissions can also be multi-speed transmissions with clutches. The transmissions can be designed as multi-speed transmissions with one or more clutches, but this can increase the complexity of the transmission. In the multi-speed transmission example, the electric machines can produce a lower continuous peak power. Another gear 236 is rotationally coupled to the intermediate shaft 234. The gear 236 meshes with a gear 238 on an output shaft 240. The transmission 238 is rotationally coupled to the output shaft 240. The term "output" refers to the direction of mechanical power flow when the electric drive unit is in a drive mode (e.g., forward or reverse).However, it goes without saying that in other operating modes, such as regeneration, the mechanical power flows in the opposite direction.

[0028] The output shaft 240 is rotationally coupled to a drive gear 242 (e.g., directly rotationally coupled). The gearbox 226 also includes gears 244, 246, 247, and 248, an intermediate shaft 250, and an output shaft 252. The output shaft 252 is also rotationally coupled to a drive gear 254. Furthermore, the gear 244 is rotationally coupled to a rotor shaft extension 256 of the rotor shaft 210. These rotor shaft extensions may or may not be included in the gearboxes. Furthermore, the gearbox 226 is arranged as a mirror image of the gearbox 224.

[0029] The electric drive unit 200 also includes a parking lock assembly 257 with a parking gear 258. In the illustrated example, the parking gear 258 is rotationally coupled to the rotor shaft extension 230. The parking gear 258 is rotationally coupled to the rotor shaft extension, which is located outside the gear 228. Alternatively, the parking gear 258 can also be arranged inside the gear 228.

[0030] A park gear engagement device 260 (e.g., a parking lock and / or other suitable device) may be used to selectively engage the park gear 258. Thus, the park gear 258 may be engaged and disengaged depending on the operating mode of the electric drive unit. For example, the park gear 258 may be engaged when the electric drive unit 200 is in a park mode and disengaged when the electric drive unit is in a drive mode. The control strategies for the park lock and drive modes are described in the Fig. 5-7. The engagement device for the park gear 260 may be electromechanically controlled in one example. However, in other examples, the park gear 260 is hydraulically and / or pneumatically actuated.

[0031] In the example shown, the rotor shafts 210, the rotor shaft extensions 220, 221, 230 and 256, the output shafts 240, 252 and the separating clutch 216 are arranged coaxially. This coaxial arrangement may be desirable for certain vehicle platforms. However, other arrangements are also possible, which are not discussed here with regard to the Fig. 3-4 will be discussed in more detail.

[0032] The Fig. The electric drivetrain architectures shown in Figures 2-4 can be used for light vehicles and light commercial vehicles, e.g., as electric drive units with a parking lock on the front axle of the vehicle in one application. To continue with this example, the parking lock on the rear axle drive can be omitted. By using this combination of electric drive units in a vehicle, the vehicle can, in a specific application, fulfill the function of an all-wheel drive in a purely electric vehicle. In other examples, the Fig. The drive units shown in Figures 2-4 can also be used in combination with an internal combustion engine for hybrid vehicles.

[0033] Fig. 3 shows another example of an electric drive unit 300 (e.g., an electric axle). The electric drive unit 300 again includes electric machines 302 and 304, transmissions 306 and 308, a separating clutch 310, and a parking lock assembly 312. In the Fig. However, in the example shown in Figure 3, all of these components are arranged axially within the electric machines 302, 304. This allows the axial width of the drive unit to be reduced and the drop height to be increased, which may be desirable in certain vehicles.

[0034] A rotor shaft extension 314 extends inward from the electric machine 302, and another rotor shaft extension 316 also extends inward from the electric machine 304. The rotor shaft extensions 314, 316 are each coupled to gears 318, 320 for rotation therewith.

[0035] The separating clutch 310 is coupled to the rotor shaft extensions 314, 316, similar to the electric drive unit 200 shown in Fig. 2. A redundant description of the separating clutch is therefore omitted for the sake of brevity.

[0036] In the example shown, a park gear 322 in the parking lock assembly 312 is coupled to the rotor shaft extension 314 between the gear 318 and the disconnect clutch 310. The output shafts 324, 326 may each extend along the sides 328, 330 of the electric machines 302, 304 to allow the drive gears 332, 334 to be positioned axially outside the electric machines. However, a different output shaft design is possible.

[0037] The transmission 306 also includes a gear 340 that meshes with the gear 318. The gear 340 is connected to an intermediate shaft 342, to which another gear 344 is coupled. The gear 344 meshes with the gear 346, which is connected to the shaft 324. The transmission 308, in the example shown, includes a mirrored gear and shaft arrangement. The gears in each of the transmissions 306 and 308 are arranged between the electric machines 302 and 304 with respect to the x-axis in the example shown. This increases the lateral compactness of the electric drive. However, other transmission architectures are also possible.

[0038] Fig. 4 shows a further example of an electric drive unit 400 with electric machines 402, 404, transmissions 406, 408, a separating clutch 410 and a parking lock arrangement 412 with a parking gear 413. The transmissions 406, 408 are arranged in relation to the Fig. 2, and redundant description is omitted for brevity. However, in order to install the disconnect clutch 410 at the desired location, shafts 414 and 416 are provided in the electric drive unit 400 with gears 418 and 420 coupled thereto, respectively, so that they rotate together. The shafts 414, 416 are in turn coupled to the opposing engageable components 422, 423 in the disconnect clutch 410. The shafts 414, 416 extend over the sides 424, 426 of the electric machines 402, 404, respectively, in the illustrated example.

[0039] The gear 418 meshes with a gear 430, which is connected to a shaft 432. The gear 430 engages the gear 418. In this way, the mechanical force can be transmitted to the separating clutch 410. The transmission 406 further comprises a shaft 434 with a gear 436 coupled thereto. The parking gear 413 is coupled to the shaft 434. The transmission 406 also comprises a gear 438, which in the example shown is coupled to the shaft 432. The gear 438, in turn, meshes with a gear 440, which is coupled to a shaft 442, which in the example shown is connected to a drive gear 444. In the example shown, the transmission 408 is arranged as a mirror image of the transmission 406. A redundant description is therefore omitted for the sake of brevity. However, in other examples, the transmissions 406 and 408 may have a different arrangement.

[0040] Fig. 5 shows a table 500 illustrating various possible operating states of the electric drive units described herein. One of the columns indicates the operating mode of the drive unit (i.e., drive (a), drive (b), or park). The next column indicates the operating state of the disconnect clutch (i.e., "engaged" or "disengaged"). The next column indicates the operating state of the parking lock assembly (i.e., "engaged" or "disengaged"). The next column indicates the operating state of the left drive system, which includes one of the electric machines and one of the transmissions. The next column indicates the operating state of the right drive system, which includes the other electric machine and the transmission. The next column shows an example drive state that may occur.

[0041] In drive mode (a), both the left and right drive systems are in drive mode, and the disconnect clutch is engaged while the parking lock assembly is disengaged. Operating conditions under which drive mode (a) can be executed include, but are not limited to, an uphill gradient, low traction, vehicle start, and the like.

[0042] In drive mode (b), both the left and right drive subsystems are in drive mode, and the disconnect clutch is disengaged, while the parking lock assembly is disengaged. Operating conditions under which drive mode (b) can be used include, among others, cornering, where the speed of the drive wheel (from left to right) varies.

[0043] In Park Mode, both the left and right drive systems are in Park Mode, and the disconnect clutch is engaged while the parking lock assembly is engaged. Operating conditions under which Park Mode may be implemented include, but are not limited to, a zero-vehicle speed condition, for example, where a drive mode selector has been placed in Park Mode by the vehicle operator.

[0044] Fig. 6 shows a method 600 for operating an electric drive unit. The method 600, as well as the other control schemes, control techniques, methods, etc. described herein, may be implemented with any of the electric drive units or combinations of electric drive units described herein. However, in other examples, the controls and / or the other control techniques, methods, etc. described herein may also be implemented with other suitable electric drive units.

[0045] At 602, the control method includes determining the operating states. The operating states may include the state of the drive mode selector (e.g., "forward drive," "reverse drive," and "park"), vehicle speed, electric machine speeds, clutch state, parking lock assembly state, and the like. These operating states may be determined through sensor inputs, modeling, etc.

[0046] At 604, the method includes determining whether a parking mode has been selected. Parking may be selected by the vehicle operator through interaction with a drive mode selector, in one example, or automatically by a control algorithm, in another example. Thus, in one example, the determination at 604 may be made via sensor inputs from a sensor coupled to a drive mode selector.

[0047] If it is determined that park mode has been selected (YES at 604), the method proceeds to 606, where the method includes engaging the disconnect clutch. In the next step (608), the parking lock assembly is engaged. The input condition for engaging the parking lock assembly may be a vehicle (e.g., transmission) speed of zero. It should be understood that the disconnect clutch and the parking lock assembly may be in a disengaged state at 602 and 604. However, in another example, the disconnect clutch may be engaged at step 602 and / or step 604. In such an example, the method may alternatively include maintaining engagement of the disconnect clutch at 606.

[0048] If it is determined that the parking mode has not been selected (NO at 604), the method proceeds to 610. At 610, the method includes determining whether the vehicle is traversing or is expected to traverse a turn in which there is a left-to-right wheel speed deviation.

[0049] If it is determined that the vehicle is in a curve (YES at 610), the method proceeds to 612. At 612, the method includes maintaining the disconnect clutch disengaged. Next, at 614, the method includes maintaining the park lock assembly disengaged.

[0050] If, however, it is determined that the vehicle is not cornering (NO at 610), the method proceeds to 616. At 616, the method includes determining whether the power unit's traction should be increased. Traction may be increased during an uphill climb, a start, etc.

[0051] If it is determined that the traction force should be increased (YES at 616), the method proceeds to 618, where the method includes engaging the disconnect clutch. Next, at 620, the method includes maintaining the park lock system unlocked.

[0052] If, however, it is determined that the traction force should not be increased (NO at 616), the method proceeds to 622, where the method includes maintaining the current operating state of the electric drive unit. Method 600 enables the drive unit's parking lock to be efficiently actuated while simultaneously adapting the unit's traction power to the current operating conditions.

[0053] Fig. 7 shows a timing diagram 700 of a use case operating scenario for an electric drive unit, such as one of the previously described electric drive units, combinations of the electric drive units, or other suitable electric drive units. In each diagram, time is indicated on the abscissa and increases from left to right. The ordinate of diagram 702 indicates the desired operating mode of the electric drive unit. The ordinate of diagram 704 indicates the configuration (i.e., "engaged" or "disengaged") of the disconnect clutch. The ordinate of diagram 706 indicates the configuration (i.e., "engaged" or "disengaged") of the parking lock assembly.

[0054] At t1, a parking mode is requested. For example, a vehicle driver can move a drive mode switch to the park position. Depending on the parking mode selection, the disconnect clutch is engaged, and the parking lock assembly is subsequently actuated.

[0055] At t2, the drive mode is requested. Depending on the drive mode selection, the parking lock assembly is disengaged, followed by the disconnect clutch. However, in other examples, the disconnect clutch may be permanently engaged. It is understood that the disconnect clutch may be engaged and disengaged while the electric drive unit is in a drive mode that depends on the unit's operating conditions.

[0056] The technical effect of the operating methods for electric drive units described here is that the parking lock is efficiently implemented via a unit integrated into one of the transmissions and the power of the drive unit is increased during a driving mode by selectively engaging the separating clutch.

[0057] Fig.1-4 show example configurations of components with relative positioning of the various components. When these elements are shown in direct contact with one another or are directly coupled to one another, they may be referred to as being in direct contact or directly coupled to one another, at least in one example. Similarly, elements that are shown next to one another or adjacent to one another may be referred to as being next to one another or adjacent to one another, at least in one example. For example, components that are in surface-to-surface contact with one another may be referred to as being in surface-to-surface contact. As another example, in at least one instance, elements that are separated from one another with only a space between them and that do not have any other components may be referred to as such.In yet another example, elements displayed above / below, on opposite sides, or to the left / right of each other may be referred to as such, relative to each other. Further, in at least one example, as illustrated in the figures, a topmost element or point of an element may be referred to as a "top" of the component, and a bottommost element or point of the element may be referred to as a "bottom" of the component. As used herein, the terms top / bottom, upper / lower, above / below may refer to a vertical axis of the figures and may be used to describe the positioning of elements of the figures relative to each other. Thus, in one example, elements displayed above other elements are arranged vertically above the other elements.As another example, the shapes of the elements depicted in the figures may be referred to as such (e.g., circular, straight, flat, curved, rounded, beveled, angled, or the like). Furthermore, in one example, elements that are coaxial with one another may be referred to as such. Further, in at least one example, the depicted elements that intersect one another may be referred to as intersecting elements or as intersecting elements. Furthermore, an element depicted inside or outside another element may be referred to as such. In other examples, elements that are offset from one another may also be referred to as such. Elements that are coaxial or parallel to one another may also be referred to as such. Furthermore, an axis about which a component rotates may be referred to as an axis of rotation.

[0058] The invention is further described in the following paragraphs. In one aspect, an electric drive unit is provided comprising a first electric machine rotationally coupled to a first drive wheel via a first transmission; a second electric machine rotationally coupled to a second drive wheel via a second transmission; a disconnect clutch configured to: in an engaged configuration, rotationally couple the first electric machine and the second electric machine; and in a disengaged configuration, rotationally decouple the first electric machine and the second electric machine; and a parking lock assembly coupled to one of the first transmission and the second transmission and configured to prevent rotation of the corresponding transmission.In one example, the disconnect clutch may be directly rotationally coupled to a first rotor shaft of the first electric machine and a second rotor shaft of the second electric machine. In another example, the park lock assembly may include a park gear rotationally coupled to a rotor shaft extension of the first electric machine or the second electric machine. Furthermore, in one example, the park lock assembly may include a park gear rotationally coupled to a shaft associated with the first or second transmission. In another example, the disconnect clutch may be connected to a first shaft associated with the first transmission and a second shaft associated with the second transmission. In one example, the first shaft, the second shaft, and the disconnect clutch may extend axially across the sides of the first electric machine and the second electric machine.In another example, the parking lock assembly may include a park gear disposed upstream of a final reduction included in the first or second transmission. In another example, the electric drive unit may further include a controller including instructions that, when executed during a zero-speed condition, cause the controller to engage the disconnect clutch and engage the parking lock assembly. In another example, the electric drive unit may further include a controller including instructions that, when executed during a drive condition or a neutral condition, cause the controller to disengage the disconnect clutch.In another example, the electric drive unit may further include a controller including instructions that, when executed during a drive condition or an idle condition, cause the controller to disengage the disconnect clutch.

[0059] In another aspect, a method of operating an electric drive unit is provided, comprising engaging a disconnect clutch and a parking lock assembly in an overlapping time interval; wherein the electric drive unit comprises: a first electric machine rotationally coupled to a first drive wheel via a first transmission; a second electric machine rotationally coupled to a second drive wheel via a second transmission; the disconnect clutch configured to rotationally couple the first electric machine and the second electric machine in the engaged configuration; and the parking lock assembly coupled to one of the first transmission and the second transmission and configured to prevent rotation of the corresponding transmission. In one example, the method may further comprise disengaging the parking lock assembly during or in anticipation of a driving condition.In one example, the method may further include selectively disengaging the disconnect clutch depending on driving conditions. In another example, the driving conditions may include cornering.

[0060] In another aspect, an electric axle is provided, comprising: a first traction motor rotationally coupled to a first drive wheel via a first transmission; a second traction motor rotationally coupled to a second drive wheel via a second transmission; a disconnect clutch configured to: in an engaged configuration, rotationally couple the first traction motor and the second traction motor; and in a disengaged configuration, rotationally uncouple the first traction motor and the second traction motor; a park lock assembly including a park gear included in either the first or second transmission and configured to prevent rotation of the corresponding transmission; and a controller including instructions that, when executed during a zero speed condition, cause the controller to engage the disconnect clutch and engage the park lock assembly.In one example, the disconnect clutch may be axially disposed between the first traction motor and the second traction motor. In another example, a gear in the first transmission and a gear in the second transmission may be axially disposed between the first traction motor and the second traction motor. In another example, the electric axle may further include a first inverter electrically coupled to the first traction motor and a second inverter electrically coupled to a second traction motor. In another example, the park lock assembly may include a park gear rotationally coupled to a rotor shaft extension of the first electric machine or the second electric machine; or the park lock assembly may include a park gear rotationally coupled to a shaft included in the first transmission or the second transmission.In another example, the controller may include: instructions that, when executed during a drive condition or a neutral condition, cause the controller to engage the disconnect clutch; and instructions that, when executed during a drive condition or a neutral condition, cause the controller to disengage the disconnect clutch and disengage the parking lock assembly.

[0061] In another illustration, an electric drive link axle is provided which includes mirrored drives, each including a traction motor and a single-speed transmission, the electric drive link axle including a lock-up clutch configured to selectively lock the joint rotation of the traction motors and a parking lock which locks the movement of one of the single-speed transmissions.

[0062] Note that the example control and estimation routines contained herein can be used with various electric drive configurations. The control methods and routines disclosed herein may be stored as executable instructions in non-transitory memory and executed by the control system, including the controller, in combination with the various sensors, actuators, and other system hardware in combination with the electronic controller. Thus, the described actions, operations, and / or functions may graphically represent code programmed into the non-volatile memory of the computer-readable storage medium in the control system of the vehicle and / or powertrain. The various actions, operations, and / or functions illustrated may be performed in the order presented, in parallel, or in some cases, omitted.Accordingly, the order of processing is not required to achieve the features and benefits of the examples described here, but is provided for convenience only. One or more of the actions, operations, and / or functions illustrated may be performed repeatedly depending on the strategy used. One or more of the process steps described here may also be omitted if desired.

[0063] Although various embodiments have been described above, they are to be considered as examples and not as limitations. Those skilled in the art will appreciate that the disclosed subject matter may be embodied in other specific forms without departing from the spirit of the subject matter. The embodiments described above are, therefore, to be considered in all respects as illustrative and not restrictive. Thus, the configurations and routines disclosed herein are exemplary in nature, and the specific examples are not to be considered as limiting, as numerous variations are possible. For example, the technology described above may be applied to powertrains that include various types of power sources, including various types of traction motors, in some cases internal combustion engines, and the like.The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations, as well as other features, functions and / or properties disclosed herein.

[0064] The following claims particularly point out certain combinations and sub-combinations that are considered novel and non-obvious. These claims may refer to "a" element or "a first" element, or the equivalent thereof. Such claims are to be construed as including the inclusion of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and / or properties may be claimed by amending the present claims or by filing new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope than the original claims, are also to be considered included within the subject matter of the present disclosure. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 11,192,436 B1

[0003]

Claims

[1] Electric drive unit, comprising: a first electric machine which is rotationally coupled to a first drive wheel via a first transmission; a second electric machine which is rotationally coupled to a second drive wheel via a second transmission; a separating clutch that is set up: in an engaged configuration, to rotatably couple the first electric machine and the second electric machine; and in a disengaged configuration, to rotationally decouple the first electric machine and the second electric machine; and a parking lock assembly coupled to the first transmission or the second transmission and configured to prevent rotation of the respective transmission. [2] Electric drive unit according to claim 1, wherein the separating clutch is directly rotationally coupled to a first rotor shaft of the first electric machine and a second rotor shaft of the second electric machine. [3] Electric drive unit according to one of the preceding claims, wherein the parking lock arrangement comprises a parking gear coupled for rotation to a rotor shaft extension of the first electric machine or the second electric machine. [4] An electric drive unit according to any preceding claim, wherein the parking lock assembly comprises a parking gear coupled for rotation to a shaft included in one of the first transmission and the second transmission. [5] Electric drive unit according to one of the preceding claims, wherein the separating clutch is coupled to a first shaft included in the first transmission and a second shaft included in the second transmission. [6] The electric drive unit of claim 5, wherein the first shaft, the second shaft, and the disconnect clutch extend axially across sides of the first electric machine and the second electric machine. [7] Electric drive unit according to one of the preceding claims, wherein: the parking lock assembly comprises a parking gear disposed upstream of a final reduction included in the first or second transmission; the separating clutch is arranged axially between the first electric machine and the second electric machine; a gear in the first transmission and a gear in the second transmission are arranged axially between the first electric machine and the second electric machine; and / or the electric drive unit further comprises a first inverter electrically coupled to the first traction motor and a second inverter electrically coupled to the second traction motor. [8] An electric drive unit according to any preceding claim, further comprising a controller including instructions which, when executed, during a zero speed condition cause the controller to: engage the clutch; and to engage the parking lock arrangement. [9] An electric drive unit according to any preceding claim, further comprising a controller including instructions which, when executed during a drive condition or an idle condition, cause the controller to: to disengage the separating clutch. [10] An electric drive unit according to any preceding claim, further comprising a controller including instructions which, when executed during a drive condition or an idle condition, cause the controller to: to disengage the separating clutch.

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