Electric drive assembly

Abstract

To provide a drive assembly equipped with a differential gear having a controllable locking action.SOLUTION: An electric drive assembly for driving a motor vehicle, comprising a housing, an electric machine with a motor shaft which can be driven in rotation about an axis of rotation A and is designed as a hollow shaft, a planetary gear, and a differential unit 5 with a differential 25, a multi-disk clutch for adjusting a locking effect of the differential, and a controllable ball ramp device for actuating the multi-disk clutch, wherein a sideshaft gear of the differential 25 has an internal toothing 58 for insertion into a shaft and a disk carrier section 59, the electric drive assembly according to claim 1, wherein the inner toothing and the disk carrier section at least partially overlap in the axial direction, and wherein the multi-disk clutch is arranged within the differential carrier and the ball ramp device is arranged outside the differential carrier.SELECTED DRAWING: Figure 1B

Description

[Technical Field]

[0001] The present invention relates to an electric drive system for driving a motor vehicle. An electric drive system typically includes an electric machine, a reduction transmission that reduces the rotational motion introduced by the electric machine, and an output splitter unit that splits the rotational motion introduced by the reduction transmission to two output shafts. Such an electric drive system may also be called an electric drive assembly or an electric axle. [Background technology]

[0002] Chinese Utility Model No. 207931450 discloses a drive assembly for a vehicle drive including an electric motor, a reduction gear, a differential, a clutch, and half shafts. The electric motor is drivingly connected to the reduction gear, which is in turn drivingly connected to the differential. The reduction gear is configured in the form of a planetary gear transmission having multiple planetary gear pairs, each consisting of two planetary gears. The planetary gear pairs are rotatably arranged on a differential case of the differential. A first planetary gear is driven by a sun gear coupled to the drive shaft of the electric motor. A second, smaller planetary gear can be connected to a fixed housing using a clutch.

[0003] WO 2020 / 069744 discloses an electric drive for driving a motor vehicle. The electric drive includes a housing assembly, an electric machine with a motor shaft formed as a hollow shaft, a planetary unit with a sun gear, a ring gear, a plurality of planet gears, and a planet carrier, and an output branch unit with an input part and two output parts. The input part is coupled to the planet carrier and rotates together with the planet carrier about a rotation axis. One of the two output parts is coupled to an intermediate shaft extending through the hollow shaft of the electric machine.

[0004] In the differential gear known from WO 2005 / 064206, the differential case has a cup-shaped case member in which halfshaft gears and compensator gears are accommodated, and a cup-shaped cover attached to the case member, with disks of a multi-plate clutch accommodated within the cover. A sleeve is arranged on the outside of the cover, and an actuator for a locking clutch can be supported axially on the sleeve and also radially on the sleeve. The actuator includes a ball ramp mechanism.

[0005] German Patent Application No. DE 10 2022 202 378 A1 discloses a transmission with an input shaft, two output shafts and a differential, which includes two planetary gear sets each with three gear set elements.

[0006] From the later published patent application DE 10 2023 122 917 A1, a differential assembly with an actuator assembly is known.

[0007] German Patent Application No. DE 10 2022 133 320 A1 discloses an electric drive with a braking device for braking the wheels of a vehicle.

[0008] There is a technical need to provide a controllable locking function for the differential in an electric drive assembly with a differential gear. At the same time, there is a need for an efficient or compact design. Summary of the Invention [Problem to be solved by the invention]

[0009] The problem underlying the invention is to propose a drive assembly with a compact design, comprising an electric machine and a differential gear with controllable locking action. [Means for solving the problem]

[0010] To achieve this object, an electric drive for driving a motor vehicle is provided, the electric drive comprising: a housing; an electric machine having a motor shaft formed as a hollow shaft that can be driven to rotate about a rotation axis by the electric machine; a planetary gear transmission having a sun gear, a ring gear, a plurality of planet gears, and a planet carrier on which the planet gears are rotatably held, the sun gear being driven to rotate about the rotation axis by the hollow shaft, and the ring gear being connected to the housing so as not to rotate relative to the planetary gear transmission; and a differential unit having a differential gear, a multi-plate clutch for adjusting the locking effect of the differential gear, and a controllable ball ramp mechanism for operating the multi-plate clutch, the differential case and the planet carrier of the differential gear being formed as a one-piece, in particular housing-like, support element, the support element being rotatable about the rotation axis within the housing. a first halfshaft gear of the differential is coupled to a first intermediate shaft extending through the hollow shaft of the electric machine; a second halfshaft gear of the differential has an internal toothing for mating with the second intermediate shaft and a disc support section for a disc set of the multi-plate clutch, the internal toothing and the disc support section at least partially overlapping in the axial direction; a ball ramp mechanism is arranged coaxially around the sleeve section of the differential case outside the differential case and has an axially supported support disc and an axially movable working disc; the differential case has a side wall section with a plurality of through openings distributed over its entire periphery, and force transmission elements extend axially through these through openings, thereby transmitting the axial movement of the working disc to a pressure plate to press against the disc set.

[0011] The advantages of the electric drive according to the present invention include a compact design with fewer parts, while integrating a controllable locking clutch for limiting the differential's compensation action as needed. Overall, this results in improved driving dynamics and requires minimal packaging adaptations on the vehicle side. The integrated design of the planet carrier and differential case as a single support element results in a space-saving design. In this case, the integrated support element fulfills three functions: planet carrier for the planetary gears, differential case for the differential gears, and outer disc support for the outer clutch discs of the friction multi-plate clutch. The unit formed by the planetary gear transmission and limited-slip differential can have a common oil system.

[0012] The housing-like support element is preferably configured compactly. To this end, the support element can be configured so that its maximum outer diameter in the region of the planet carrier is less than 1.25 times the maximum outer diameter in the region of the differential case. Alternatively or additionally, the support element can be configured so that the planet gears rotatably held therein at least partially overlap in the axial direction with the halfshaft gears likewise rotatably held on the support element.

[0013] The planet carrier preferably has a plurality of radial windows distributed around its circumference, which are penetrated by the planet gears. The inner engagement areas of the planet gears with the sun gear are located inside the housing-like planet carrier, and the outer engagement areas of the planet gears with the ring gear are located outside the housing-like planet carrier. For a particularly compact design, the axial distance from the window center plane to the differential center plane can be smaller than the axial distance from the differential center plane to the end bearings that rotatably support the differential case in the housing. The integral support element can be manufactured as a cast part made of light metal or a light metal alloy, for example, an aluminum alloy.

[0014] The friction multi-plate clutch is arranged to act between the differential case and the second half-shaft gears. The pressure of the disc set creates a locking effect between the case and the half-shaft gears. The disc set has outer discs connected to the differential case in a form-locking manner and axially movable, and inner discs connected to the second half-shaft gears in a rotation-locking manner and axially movable. The disc set can be axially pressed by a pressure ring and is axially supported on a bearing surface assigned to the differential case. For this purpose, a support ring can be arranged or inserted in the differential case, and the disc set is axially supported via this support ring. The use of a support ring offers further structural possibilities; it is obvious that the disc set can also be supported directly on the differential case. The friction multi-plate clutch can be designed to transmit a target clutch torque, particularly greater than 1600 Nm, in particular greater than 1700 Nm, for example, approximately 1800 Nm. In this case, the factor representing the power density or radial structural size, which is made up of the maximum outer diameter of the differential case in millimeters and the transmittable clutch torque in Nm, may be less than 0.9, in particular less than 0.8.

[0015] For example, the support ring may have an inner diameter smaller than the smallest inner diameter of the differential inlet opening, smaller than the central diameter of the disk set, and / or smaller than the largest outer diameter of the second halfshaft gear. In this case, the inlet opening of the differential case may be larger than the central diameter of the disk set. The support ring may have a ring surface, particularly a conical ring surface, on the side facing the differential gear set, tapering toward the disk set. These features, alone or together, contribute to a compact design while providing good axial support for the disk set. The radially largest section of the halfshaft gear may be positioned so that it overlaps the support ring axially or is as close as possible to the disk set axially. The support ring may further have a retaining section that protrudes axially from the support surface and is inserted into the inlet opening of the differential case. In this way, the support ring is radially held or centered on the differential case.

[0016] The differential housing preferably has a side wall section that is continuous with the sleeve section, through which the force transmission element extends. The operating element may be arranged coaxially with the sleeve section between the actuating ring of the ball ramp mechanism and the force transmission element, with an annular gap being formed between the outer surface of the sleeve section and the operating element. The side wall section may be inserted into a turned section of the peripheral wall section of the differential housing and may be firmly connected to the turned section in a material-tight manner, particularly by welding.

[0017] The ball ramp device can be driven by a drive source, for example, a controllable electric motor, and is designed to convert the introduced rotational movement into axial movement. For this purpose, the operating disk and the support disk can each have the same circumferentially reduced depth in end plan view. A ball is accommodated in each pair of opposing ball grooves, and the operating disk and the support disk are axially supported relative to each other via these balls. In this case, the operating disk is preferably supported radially on the support disk exclusively via the balls. Since no separate radial support is required for the operating disk, an annular gap can be formed between the outer surface of the sleeve segment and the operating disk. This has a further advantageous effect on the free construction space for the sleeve segment, which can be optimized in terms of construction space and stress.

[0018] A spring element is preferably arranged axially between the side wall section and the operating element, thereby applying a spring-like return force to the operating element that counteracts the operating force of the ball ramp mechanism. The spring element may have any suitable design for returning the operating element back to the starting direction, opposite the operating direction of the actuation disk. For example, the spring may be ring-shaped and inserted into a recess or axial recess in the side wall of the differential housing. To avoid jamming, the spring is held on the periphery of the side wall with radial play. In particular, the spring element may be configured as a wave spring or a disc spring, although other designs are also possible, such as multiple coil springs distributed over the entire circumference.

[0019] In one embodiment, a thrust bearing can be arranged between the actuation disk and the operating element. The thrust bearing transmits axial forces between the actuation disk and the operating element, i.e., in the closing and opening directions, while simultaneously isolating the two elements from pivoting relative to one another.

[0020] In one embodiment, the support disk of the ball ramp mechanism can be rotated by a drive source, while the actuation disk is non-rotatable and axially movable. Naturally, other configurations are also possible, such as the actuation disk being rotatable and axially movable, while the support disk is non-rotatable and axially supported. The support disk and the actuation disk have ball grooves with variable depths in the circumferential direction on their opposing end faces. The ball ramp mechanism can be configured so that the centers of the balls accommodated in the ball grooves radially overlap the thrust bearing and / or the support bearing for the support ring. This achieves an advantageous axial force transmission with a low tilting moment.

[0021] According to one embodiment, the sleeve section of the differential case has a bearing seat on which a pivot bearing for the support ring is mounted. Between the axial side surface of the sleeve section and the bearing surface, the differential case may have a transition section that is concave in semi-longitudinal section and can extend from the side surface in the axial direction at least as far as the actuation ring. The transition section preferably has a free outer surface at least as far as the support disk, meaning that no components are supported in the housing section between the end face and the support ring or support bearing. This section of the housing section, which is subject to high forces during operation, can therefore be configured or designed to be optimized in terms of stress, which has a positive effect on the service life of the assembly.

[0022] The minimum outer diameter of the concave transition section may be smaller than the outer diameter of the bearing seat for the pivot bearing. Alternatively or additionally, the concave transition section may have a curvature with a radius that is at least 0.5 times the minimum axial distance between the actuation disc and the flange section of the differential case. Further alternatively or additionally, the minimum outer diameter of the concave transition section may be smaller than the radius of the external toothing of the clutch hub. One or more of these specific configurations may reduce the load on the differential case at this section.

[0023] The differential includes a plurality of differential gears rotatably supported within a differential case around axles extending at an angle to the rotation axis, and two half-shaft gears supported within the differential case coaxially with the rotation axis and meshing with the differential gears. The gear axes of the differential gears form a differential center plane. The differential may be configured as a bevel gear differential, with the differential gears and half-shaft gears each configured as bevel gears. Alternatively, the differential may be configured as a crown gear differential, with the differential gears configured as spur gears and the half-shaft gears configured as crown gears.

[0024] Next, a preferred embodiment will be described with reference to the drawings. [Brief explanation of the drawings]

[0025] [Figure 1A] 1 is a longitudinal section view of an electric drive assembly according to the invention in a first embodiment; [Figure 1B] FIG. 1B is an enlarged view showing details of a differential unit of the electric drive assembly of FIG. 1A. [Figure 2] FIG. 1B is a schematic diagram illustrating the electric drive assembly of FIG. 1A. [Figure 3] FIG. 4 is a longitudinal sectional view of a differential unit of an electric drive assembly according to the present invention in a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0026] 1A, 1B, and 2 are described below. An electric drive assembly 2 according to the present invention, which may be referred to simply as an electric drive, is shown. The electric drive assembly 2 includes an electric machine 3, a planetary gear transmission 4 drivingly coupled to the electric machine 3, and a differential unit 5 for distributing rotational motion from the planetary gear transmission 4 to two output sections 6, 7 of the electric drive assembly 2. The electric machine 3, the planetary gear transmission 4, and the differential unit 5 are housed within a housing assembly, which may be referred to simply as a housing 8. The differential unit 5 includes a multi-plate clutch 41 for locking the compensating motion of the differential output section and a ball ramp mechanism 45 for controlling the clutch torque or locking torque. Therefore, the differential unit may also be referred to as a limited-slip differential unit.

[0027] The electric machine 3 serves as a drive source for driving the drive shaft of the vehicle. The electric machine 3 is controlled by power electronics, such as a pulse inverter, incorporating an electronic control unit (ECU). For power supply, the electric machine 3 can be connected to a battery (not shown). The electric machine 3 has a stator 21 rigidly connected to the housing 8 and a rotor 22 rigidly connected to the motor shaft 10 for torque transmission.

[0028] The motor shaft 10 is formed as a hollow shaft, is supported in the housing 8 by a first bearing 11 and a second bearing 12 so as to be rotatable about the rotation axis A, and can be driven to rotate by the rotor 9. A drive part 13 is provided on the end of the motor shaft facing the transmission 4, and this drive part is connected to the hollow shaft 10 via a shaft connection part 14 (spline) so as not to rotate relative to the hollow shaft 10, and serves to transmit rotational motion to the planetary gear transmission 4. The planetary gear transmission 4 includes a sun gear 15 formed integrally with the drive part 13, a ring gear 16 connected to the housing 8 so as not to rotate relative to the hollow shaft 10, a plurality of planet gears 17, and a planet carrier 18 on which the planet gears 17 are rotatably supported and which revolves together with the planet gears.

[0029] In this embodiment, the planetary gear 17 is formed as a double planetary gear, each having a first planetary gear tooth row 37 engaged with the sun gear 15 and a second planetary gear tooth row 38 engaged with the ring gear 16, but is not limited to this. The tooth rows 37, 38 of the planetary gear 17 may be formed as helical tooth rows, so that the axial force acting from the sun gear 15 on the first planetary gear tooth row 37 and the axial force acting from the ring gear 16 on the second planetary gear tooth row 38 are directed in opposite directions to each other.

[0030] The ring gear 16 is connected to a housing portion 32 of the housing 8, for example, by means of a screw that can be axially screwed into the housing portion 32. The planetary carrier 18 is rigidly connected to the input portion of the differential unit 5, so that the planetary carrier and the differential unit rotate together around a rotation axis A. The differential unit 5 includes a differential case 19 as an input portion, a plurality of differential gears 20 that revolve together with the differential case 19, and two half-shaft gears 6, 7 as an output portion that mesh with the differential gears 20. In this embodiment, the differential gears 20 and the half-shaft gears 6, 7 are each formed as bevel gears, but this is not limiting. The differential unit 5 divides the introduced rotational motion between the two half-shaft gears 6, 7, and in this case, compensation occurs based on the differential gear 20 located between the two half-shaft gears. Therefore, the differential gear 20 can also be called a compensation gear. The planet carrier 18 and the differential case 19, which may also be called a differential carrier, are formed in one piece in this embodiment. Both components formed in this way may also be called support elements.

[0031] The carrier element is shaped like a housing and can be manufactured as a cast part, for example, from a light metal or light metal alloy, in particular an aluminum alloy. This allows for efficient construction of even more complex shapes. In the illustrated configuration, the maximum outer diameter D18 in the region of the planet carrier 18 is less than 1.25 times the maximum outer diameter D19, in particular in the region of the differential case 19. Furthermore, the carrier element is configured so that the planet gear 17 rotatably supported therein at least partially overlaps the halfshaft gear 6 adjacent to the planet gear in the axial direction. This contributes to a compact construction.

[0032] It can further be seen that the planet carrier 18 has a number of circumferentially distributed windows 68 or through-holes pierced by the planet gears 17. The planet gears 17 mesh with the sun gear 15 on the inside and with the ring gear 16 on the outside. In this case, the axial distance B3 from the window center plane E68 to the differential center plane E25 is smaller than the axial distance B4 from the differential center plane E25 to the side bearings 69 in which the differential case 19 is rotatably supported in the outer housing, in particular, it is smaller than 0.9 or 0.8 times the axial distance B4. This also contributes to a compact design.

[0033] An intermediate shaft 23 is connected to the first halfshaft gear 6 so as to be non-rotatable relative to the first halfshaft gear, thereby transmitting torque to a halfshaft (not shown) whose other end is connected to the first halfshaft gear. The intermediate shaft 23 extends through the hollow shaft 10, and an annular chamber 24 with two end openings is formed between the intermediate shaft and the hollow shaft. A second intermediate shaft or halfshaft (not shown) is connected to the second halfshaft gear 7 for transmitting torque to the associated second wheel.

[0034] The housing 8 of the electric drive 2 comprises a first housing part 31 forming an accommodation space for the electric machine 3, a second housing part 32 in which the transmission units 4, 5 are at least partially accommodated, and an intermediate housing part 33 arranged between the end housing parts 31, 32. The intermediate housing part 33 has an intermediate wall 34 that spatially separates a motor chamber 35 and a transmission chamber 36. The motor chamber 35 can be dry, i.e., lubricant-free, and can be sealed outwardly with corresponding seals 26, 27, 28, 29, while the transmission chamber 36 can be filled with lubricant.

[0035] A friction multi-plate clutch 41 is provided in the differential case 19 to control the locking action of the differential. The multi-plate clutch 41 is arranged to act between the differential case 19 and the half-shaft gears 7. Operating the clutch in the closing direction thereby creates a locking action between the case and the half-shaft gears. The clutch has an outer disk 42 positively and axially movably connected to the differential case 19 and an inner disk 43 non-rotatably and axially movably connected to the second half-shaft gear 7. The disk set formed by the outer and inner disks can be pressed axially via a pressure plate 44. The pressing force is controlled by a ball ramp mechanism 45. Force is transmitted from the ball ramp mechanism 45 to the pressure plate 44 via several force transmission elements 46, shown here by dashed lines, distributed over the entire circumference. The force transmission elements are preferably configured as pins extending axially through through openings in the differential case 19. The pin is supported axially at one end against the operating element 55 and at the other end against the pressure plate 44 .

[0036] The pressure plate 44 presses against the disc set, which reduces the compensating movement between the halfshaft gear 6 and the differential case 19, and therefore also the compensating movement between the two halfshaft gears 6, 7. The torque transmittable by the multi-disc clutch 41 can be variably adjusted as required by corresponding control of the ball ramp mechanism 45. The clutch can be fully opened, so that the two halfshaft gears can rotate freely relative to one another ("open" differential), or fully closed, so that the compensating movement of the halfshaft gears is completely blocked ("closed" differential), or the clutch can be operated in any intermediate state, so that the compensating movement between the halfshaft gears is partially blocked.

[0037] Ball ramp mechanism 45 is arranged coaxially with differential case 19 and lies in a separate cross-sectional plane, so that it can be driven by a drive source (not shown). Differential case 19 has, inter alia, a side wall section 47, through which the force-transmitting elements extend, and a sleeve section 48 axially adjoining this side wall section, around which ball ramp mechanism 45 is arranged. An annular gap is formed between the outer surface of sleeve section 48 and at least some components of ball ramp mechanism 45. Side wall section 47 is inserted into a turning 49 in a peripheral wall section of differential case 19 and is firmly connected to this turning 49, for example by welding.

[0038] The ball ramp mechanism 45 comprises a support disk 50 axially supported on the sleeve section 48 and an actuating disk 51 axially movable relative to the support disk. In the exemplary embodiment, the support disk 50 can be rotatably driven by a drive source, while the actuating disk 51 is held non-rotatably relative to a stationary housing part via an anti-rotation mechanism. For operation, the support disk 50 has a toothed segment 52 with which a pinion for rotational drive can engage. Naturally, other configurations are also possible, for example, with a rotatably driven actuating disk or other forms of torque transmission, such as a rack or spindle drive.

[0039] The support disk 50 and the actuation disk 51 each have, on their opposing end faces, a number of circumferentially extending ball grooves 53, 54, in which one ball is guided. The balls are located in another cross-sectional plane and are therefore not visible here. The ball grooves 53, 54 are designed so that the rotational movement imparted to the support disk 50 by the drive source is converted into axial movement of the actuation disk 51. For this purpose, the actuation disk 51 and the support disk 50 may each have the same circumferentially reduced depth in an end view. However, it is also possible for only one of the disks to have ball grooves. In this case, the actuation disk 51 is radially supported relative to the support disk 50 exclusively via the balls. Therefore, radial support relative to the differential case is not required, and the sleeve section 48, in particular, can be designed advantageously with respect to the loads occurring during operation.

[0040] A ring-shaped operating element 55 is provided for transmitting force between the ball ramp mechanism 45 and the clutch. The operating element 55 is arranged coaxially with respect to the ball ramp mechanism 45 and axially movable between the actuation disk 51 and the side wall of the differential case 19. Centering of the operating element 55 with respect to the rotation axis A or the sleeve section 48 can be achieved via a force-transmitting element 46 connected to the operating element. Force transmission between the actuation disk 51 and the operating element 55 can be achieved via an optional thrust bearing 57. The thrust bearing 57 is arranged coaxially with respect to the ball ramp mechanism 45 and transmits axial forces while separating the relative rotational movement. The thrust bearing 57 is supported radially relative to the operating element 55. For this purpose, the operating element 55 has an axially protruding, in particular annular, collar on the side facing the actuation disk 51, which collar forms a recess for the thrust bearing 57.

[0041] The axial movement of the actuation disc 51 is transmitted to the pressure plate 44 via the thrust bearing 57 , the operating element 55 and the force transmission element 46 .

[0042] The return occurs via a spring element 56, which is arranged axially between the differential case 19 and the operating element 55, and which exerts a spring-like return force on the operating element 55 that counteracts the operating force of the ball ramp mechanism 45. In this embodiment, the spring element 56 is configured as a disc spring and is arranged coaxially with respect to the sleeve section or the operating element. Naturally, other spring shapes for the return spring are also possible. For radial positioning or for a short axial construction, the spring element 56 can be arranged at least partially in a recess 67 or an axial recess in the side wall section 47 of the differential case 19.

[0043] The operating element 55, thrust bearing 57, support disk 50, and actuation disk 51 are radially spaced from the outer surface of the sleeve section 48. The support disk 50 of the ball ramp mechanism is axially supported on the sleeve section 48. The differential case 19 has a bearing seat 39, on which a pivot bearing 40, specifically configured as a combined thrust / radial bearing, is mounted. The bearing is axially supported on the sleeve section 48 by a retaining ring, although other configurations are also possible. Between the side wall section 47 and the bearing seat 39, the differential case 19 has a concave transition section 30 that extends axially from the side surface approximately to the support disk 50. The transition section 30 has a free outer surface, meaning that no components are arranged or supported on the differential case between the side surface and the pivot bearing 40. The minimum outer diameter D30 of the concave transition section 30 may be smaller than the outer diameter D39 of the bearing seat 39 for the pivot bearing 40. The curvature of the concave transition section 30 may have a radius that is at least 0.5 times the minimum axial spacing between the actuation disc 51 and the side wall of the differential case 19 .

[0044] A particular feature of this electric drive is its compact design, which is due in particular to the design of the second halfshaft gear 7 and the differential case 19. The second halfshaft gear 7 has internal teeth 58 for mating with a second intermediate shaft (not shown) and a disk carrier section 59 for the multi-plate clutch 41. The internal teeth for the shaft connection and the disk carrier section at least partially overlap in the axial direction, which results in an axially compact design.

[0045] The second halfshaft gear 7 has engagement means on its hub section or outer surface, with which the inner discs 43 of the clutch are non-rotatably but axially movably engaged. Therefore, the disc support section 59 can also be called an inner disc support. The disc set can be pressed axially by a pressure plate 44 and is axially supported on an optional support plate 60 located within the differential case 19. The outer disc support, to which the outer discs 42 are non-rotatably but axially movably connected, is formed within the differential case 19.

[0046] The support plate 60 is preferably configured so that its inner diameter d60 is smaller than the smallest inner diameter D61 of the differential inlet opening 61, and / or smaller than the central diameter D41 of the disk set, and / or smaller than the largest outer diameter D7 of the second halfshaft gear 7. In this case, the inlet opening 61 of the differential case 19 may be larger than the central diameter D41 of the disk set. On its side facing the differential gear set, the support ring preferably has a conical ring surface 62 that tapers toward the disk set. In this way, the radially outer sections of the halfshaft gears 7 can be arranged to overlap the support plate 60 in the axial direction or to be as close as possible to the disk set in the axial direction. The support plate 60 preferably has a retaining section 63 that protrudes axially from its rear support surface and is inserted into the inlet opening 61 of the differential case 19. In this way, the support plate 60 is radially held or centered on the differential case 19.

[0047] FIG. 2 is a schematic diagram of an electric drive assembly 2 according to the invention, in which the planet gear 17 has only one planet gear toothing 37 .

[0048] FIG. 3 shows a longitudinal section of a differential unit of an electric drive assembly according to the invention in a slightly different embodiment. A particular feature of this embodiment is that the separation plane E32 of the housing 8 between the intermediate housing section and the end-side second housing section 32 is arranged axially overlapping the central section of the differential. In this case, it is specified that the axial distance B1 between the separation plane E32 of the second housing section 32 and the end face 64 of the differential case or the sleeve section 48 of the differential case is less than 150 mm, and / or the axial distance B2 between the separation plane E32 and the axial abutment surface 65 of the outer joint part 66 of the constant velocity joint (not shown), which is to be connected to the halfshaft gear 7, is less than 155 mm. In this case, the coefficient representing the axial structural size, which is formed by the axial distance B2 in millimeters and the transmittable clutch torque in Nm, can be less than 1.0, in particular less than 0.9. These features, individually or together, contribute to an axially compact structural design.

[0049] The electric drive according to the invention integrates a controllable lock for limiting the compensation action of the differential as required, while at the same time offering the advantage of a compact design with fewer parts, which in turn improves driving dynamics and requires only minor adaptations in terms of packaging on the vehicle side. [Explanation of symbols]

[0050] 2 Electric Drive Assembly 3 Electrical Machinery 4 Planetary gear transmission 5 Differential unit 6 Half shaft gear / output part 7 Half shaft gear / output part 8. Housing 10 Motor shaft 11,12 Bearings 13 Drive unit 14 Shaft joint 15 Sun Gear 16 Ring gear 17 Planetary gear 18 Planet Carrier 19 Differential case 20 Differential gear 21 Stator 22 rotor 23,23' intermediate shaft 24 Circular Chamber 25 Differential device 26~29 Sealing material 30 Transition Section 31 first housing part 32 second housing part 33 Intermediate housing part 34 Intermediate Wall 35 Motor Room 36 Transmission Room 37,38 Planetary gear tooth arrangement 39 Bearing seat 40 Pivot bearing 41 Multi-plate clutch 42 outer disc 43 Inner Disc 44 Pressure Plate 45 Ball ramp mechanism 46 Force transmission element 47 Side wall division 48 sleeve divisions 49 Turning section 50 support discs 51 Working disc 52 tooth arch segments 53,54 Ball groove 55 Operating elements 56 Spring element 57 Thrust bearing 58 Inner dentition 59 Disc support section 60 Support Plate 61 Introduction opening 62 Ring surface 63 Retention category 64 End face 65 Contact surface 66 Outer part of joint 67 Notch 68 Windows 69 Bearings A rotation axis B interval D,d diameter E plane

Claims

1. 1. An electric drive assembly for driving a motor vehicle, comprising: a housing (8); an electric machine (3) having a motor shaft formed as a hollow shaft (10) that can be driven in rotation about a rotation axis (A) by the electric machine (3); a planetary gear transmission (4) including a sun gear (15), a ring gear (16), a plurality of planet gears (17), and a planet carrier (18) on which the planet gears (17) are rotatably held, the sun gear (15) being rotatable about the rotation axis (A) by the hollow shaft (10), and the ring gear (16) being connected to the housing (8) so as not to rotate relative to the sun gear (15); a differential unit (5) including a differential (25), a multi-plate clutch (41) for adjusting the locking action of the differential, and a controllable ball ramp mechanism (45) for operating the multi-plate clutch (41); Including, a differential case (19) of the differential gear (25) and the planet carrier (18) form an integral support element, the support element being supported in the housing (8) so as to be rotatable about the rotation axis (A); a first halfshaft gear (6) of the differential (25) is connected to a first intermediate shaft (23) extending through the hollow shaft (10) of the electric machine (3); a second halfshaft gear (7) of the differential (25) has an internal toothing (58) for mating with a second intermediate shaft (23) and a disc support section (59) on which a disc set of the multi-plate clutch (41) is arranged, the internal toothing (58) and the disc support section (59) at least partially overlapping in the axial direction; The ball ramp mechanism (45) is disposed coaxially around the sleeve section (48) of the differential case (19) outside the differential case (19), and includes an axially supported support disk (50) and an axially movable operating disk (51); The differential case (19) has a side wall section (47) with a plurality of through openings distributed over its entire circumference, through which force transmission elements (46) extend in the axial direction, thereby transmitting the axial movement of the actuation discs (51) to a pressure plate (44) and pressing against the disc set. Electric drive assembly.

2. 2. An electric drive assembly according to claim 1, characterized in that the maximum outer diameter (D18) of the support element in the region of the planet carrier (18) is smaller than 1.25 times the maximum outer diameter (D19) of the support element in the region of the differential case (19).

3. 3. An electric drive assembly according to claim 1, wherein the planet carrier (18) has a plurality of radial windows (68) arranged around its circumference, the windows being penetrated by the planet gears and forming a window center plane (E68), and the axial distance (B3) from the window center plane (E68) to the differential center plane (E25) is smaller than the axial distance (B4) from the differential center plane (E25) to end bearings (69) that rotatably support the differential case (19) in the housing (8).

4. 3. The electric drive assembly according to claim 1, wherein the disc set comprises outer discs (42) connected to the differential case (19) in a positively locking and axially movable manner and inner discs (43) connected to the second halfshaft gear (7) in a non-rotatable and axially movable manner, the disc set being axially pressable via the pressure plate (44) and axially supported on the differential case (19) via abutment surfaces (65) associated with the differential case (19).

5. 3. The electric drive assembly according to claim 1, wherein the differential case (19) has an introduction opening (61) for introducing the second halfshaft gear (7), and the minimum inner diameter (D61) of the introduction opening (61) is larger than the central diameter (D41) of the disc set of the multi-plate clutch (41).

6. 6. The electric drive assembly according to claim 5, wherein a ring-shaped support plate (60) is arranged in the differential case (19), and the disc set is axially supported on the differential case (19) via the support plate, and the support plate (60) has an inner diameter (d60) that is smaller than at least one of the minimum inner diameter (D61) of the introduction opening (61), the central diameter (D41) of the disc set, and the maximum outer diameter (D7) of the second halfshaft gear (7).

7. 7. The electric drive assembly according to claim 6, wherein the support plate (60) has a support surface that is axially supported on the differential case (19) and a holding section (63) that protrudes axially from the support surface, the holding section (63) being inserted into the introduction opening (61) of the differential case (19), thereby holding the support plate (60) radially on the differential case (19).

8. 3. The electric drive assembly according to claim 1, wherein the differential case (19) has a side wall section (47) connected to the sleeve section (48), through which the force transmission element (46) extends, and an operating element (55) is arranged coaxially with the sleeve section (48) between the support disk (50) of the ball ramp mechanism (45) and the force transmission element (46), and an annular gap is formed between the outer surface of the sleeve section (48) and the operating element (55).

9. 9. An electric drive assembly according to claim 8, characterized in that the side wall sections (47) are inserted into turned sections (49) of the peripheral wall sections of the differential case (19) and are firmly connected to the turned sections by welding.

10. 9. The electric drive assembly according to claim 8, wherein the sleeve section (48) of the differential case (19) has a bearing seat (39) on which a pivot bearing (40) for the support disc (50) is mounted, and the differential case (19) has a concave transition section (30) between the side wall section (47) and the bearing seat (39) of the sleeve section (48), the transition section extending axially from the side of the side wall section (47) to at least the working disc (51).

11. 9. The electric drive assembly according to claim 8, wherein a spring element (56) is arranged axially between the side wall section (47) and the operating element (55) to apply a spring-like return force to the operating element (55) acting against the operating force of the ball ramp mechanism (45), and the side wall section (47) has a notch (67) in which the spring element (56) is at least partially arranged.

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