Electric drive units for automobiles

Abstract

The present invention relates to an electric drive unit for a motor vehicle, comprising an electric drive device (5), a power train (6) arranged downstream of the electric drive device (5) in the power flow direction and arranged in a power train housing (4), means for circulating a coolant in an interior space (7) of the power train housing (4), and a rotatably arranged input shaft (19) or output shaft (18) of the power train (6), the power train housing (4) consisting of a peripheral housing wall (11) annularly surrounding a central axis (A) and an end wall (13), the end wall (13) extending radially outward from an opening (17) for the input shaft (19) or output shaft (18) to a connecting region (14) where the end wall (13) and the peripheral housing wall (11) are connected to each other. In order to improve the flow conditions by structural measures, particularly in the region of the powertrain housing where the coolant is led out or sucked out during circulation, an annular chamber (33) is provided which extends circumferentially along the connecting region (14) and which is connected to the interior space (7) via individual openings (40).

Description

[Technical field]

[0001] The invention relates to an electric drive unit for a motor vehicle, which comprises an electric drive, a transmission arranged downstream in the power flow direction with respect to the electric drive and arranged in a transmission housing, means for circulating a coolant in the interior of the transmission housing, and a rotatably arranged input or output shaft of the transmission, the transmission housing consisting of a circumferential housing wall annularly surrounding a central axis and an end wall, the end wall extending radially outward from an opening for the input or output shaft as far as a connecting region in which the end wall and the circumferential housing wall are connected to one another.

[0002] Such an electric drive unit is used as a traction drive of a vehicle. The electric drive unit is preferably used as a component of an electric drive axle for a commercial vehicle. In this type of vehicle axle, a multi-stage transmission is provided downstream of an electric drive, which is advantageously arranged weight-wise near the center of the vehicle. The transmission is arranged alone or together with the electric drive in a housing. The housing is composed of a housing circumferential wall that surrounds the interior of the transmission together with the transmission elements arranged therein and an end wall that closes the interior at the end side. The housing circumferential wall is mainly annular in design. The end wall extends substantially radially and has a central opening through which the transmission input shaft or the transmission output shaft is guided.

[0003] To cool the powertrain elements, a coolant is circulated in the interior of the powertrain housing. This is done in a circuit in which the coolant flows through all possible mechanically loaded areas of the powertrain, including the existing rolling bearing elements for the rotating powertrain elements. Preferably, powertrain oil is used as the coolant, so that this liquid not only lubricates the powertrain elements, but also takes care of the heat removal.

[0004] In particular, if the transmission is designed as a planetary gear, a strong rotation of the transmission oil occurs on the inner surface of the housing jacket. This rotation of the oil creates an annular oil sump on the inner surface of the transmission housing, which in the case of injection lubrication makes it difficult to achieve an ideal outflow of the lubricant. In particular, it is difficult to suck out the oil during oil circulation, because instead of flowing completely into the existing oil outlet, the oil passes by the oil outlet with high flow velocities due to the aforementioned rotation.

[0005] The object of the invention is to improve by constructive measures the flow conditions, in particular in the region of the powertrain housing where the coolant is led away or sucked out of the powertrain housing during circulation.

[0006] To achieve this goal, an electric drive unit is proposed having the features of claim 1.

[0007] In the present invention, an additional annular chamber, which is connected to the interior of the gear housing only via the individual openings, serves to calm the coolant flowing or rotating at high speed in another region of the gear housing. The annular chamber has the function of a calming zone for the coolant. For this purpose, an annular calming zone is arranged, preferably with a large diameter. The annular calming zone is open towards the interior in a defined circumferential portion, i.e. in the region of the individual openings, so that the coolant, in particular the gear oil, can flow into the annular chamber via these openings and be calmed there. In contrast, in another circumferential portion, the annular chamber is essentially closed towards the gear interior, so that no significant coolant exchange takes place in this circumferential region and the flow of the liquid, in particular the liquid, can be calmed in this region of the annular chamber. As a result of the calming of the flows, the oil suction or oil outflow is significantly improved, especially in the region of the oil suction, even if the space situation is insufficient in any case.

[0008] According to a preferred configuration of the annular calming zone, the openings and the non-opening circumferential portions are advantageously arranged alternately in the circumferential direction. For example, the number of openings in the annular chamber and the number of non-opening circumferential portions may be between 6 and 10, respectively.

[0009] With regard to the annular chamber serving as the calming zone, it is proposed that the walls of the annular chamber are formed partly by the housing circumferential wall and partly by the end wall, which end wall then being a separating wall between the transmission and the electric motor of the drive unit.

[0010] In order to ensure that the annular chamber is arranged with a large diameter, it is proposed that the diameter of the annular chamber is larger than the largest diameter that the inner surface of the circumferential housing wall has outside the region of the annular chamber.

[0011] It is further proposed that the annular chamber is defined by an inner chamber wall towards the interior and by an outer chamber wall towards the outside of the housing circumferential wall, the opening and the non-opening circumferential portion being located within or at the inner chamber wall.

[0012] According to a particularly advantageous embodiment from the viewpoint of manufacturing, the inner chamber wall is formed in a concave-convex shape, the projections forming circumferential sections without openings and the circumferential regions between the projections forming the openings. Preferably, the axial extent of the openings, i.e. their extension in the axial direction, is shorter than the axial extent of the annular chamber.

[0013] Furthermore, with regard to the cross-sectional geometry of the annular chamber, it is proposed that the length of the annular chamber in the axial direction is greater than the maximum width of the annular chamber measured between the inner and outer chamber walls.

[0014] Preferably, the housing circumferential wall is provided with a number of holes or passages, which lead from the annular chamber to the outer surface of the housing circumferential wall. These holes or passages can serve different functions and purposes in connection with the coolant guidance. For example, the outer ends of the holes or passages can have a thread for arranging an air bleed valve, an air bleed filter, a measuring plug for detecting the coolant level, a magnetically acting catcher for metal cuttings or a temperature sensor in the respective hole or passage. One of the holes or passages, preferably provided at the lowest point of the annular chamber, serves to drain or drain the power train oil into a collector arranged below.

[0015] Since the functions associated with the holes or passages partially require more space, it is proposed in a further embodiment that the housing circumferential wall is formed as a radially widened flange in comparison with the remaining part of the housing circumferential wall so as to surround the annular chamber, and the holes or passages lead through the flange to the outer surface of this flange, i.e. the additional volume associated with the radially widened flange can be used to obtain space for a sufficiently large number of holes or passages and for the technical purpose assigned to these holes or passages.

[0016] Additionally, the flange can be used for screw fastening the power train housing to a directly adjacent motor housing, for example of an electric drive, for which purpose it is advantageous if the flange has axial openings arranged distributed over its entire circumference for receiving a number of screws or threaded bolts, for example threaded bolts, as rigid connecting elements between the power train housing and the motor housing.

[0017] In order to achieve particularly favorable flow conditions in the region of the calming zone, it is proposed that the end wall is provided with a collar extending into the annular chamber, the transition between the radially extending part of the end wall and the collar being formed as a radius, preferably the radius of this radius being 25% to 75% of the maximum width of the annular chamber measured between the inner and outer chamber walls.

[0018] The walls of the annular chamber, in the area formed by the peripheral housing wall, are U-shaped walls of a groove which is open towards the end wall.

[0019] The groove, which is open towards the end wall, offers the possibility of forming a collar on the end wall, which extends into the annular chamber and which is in contact with one of the walls of the groove, preferably the radially outer wall of the groove. In this configuration, the groove not only has the role of calming the coolant flow, but at the same time it also serves as a centering element, by means of which the end wall is fixed in position in the connection area with the housing circumferential wall in an accurately aligned manner. For this mutual alignment, it is additionally advantageous if a collar or centering collar formed on the end wall is in contact with the corresponding wall of the groove with at least one annular sealing element therebetween, so that a liquid-tight connection is achieved between the end wall and the housing circumferential wall in the connection area.

[0020] Preferably, the sealing element is fitted into a sealing groove formed in the collar or in the centering collar.

[0021] One configuration of the electric drive unit provides that the transmission is a planetary gear mechanism, the internal gear of which is an inner surface of the housing casing that is provided with a tooth row, the tooth row being configured as a helical tooth row in such a way that the cooling liquid collected therein is conveyed towards the longitudinal section of the housing casing that has the opening.

[0022] Further advantages and details of the electric drive axle for commercial vehicles become apparent from the following description of the exemplary embodiment shown in the drawing. [Brief description of the drawings]

[0023] [Figure 1] FIG. 2 shows an electric drive axle for a commercial vehicle with a multi-stage transmission in the form of a double planetary gear mechanism, a transmission housing for accommodating the transmission, a motor housing connected to the transmission housing, and an axle housing also connected to the transmission housing. [Diagram 2] FIG. 2 shows a perspective, partially cut-away view of the powertrain housing together with the planet gear support of the powertrain. [Diagram 3] FIG. 2 illustrates a perspective, partial cross-sectional view of a powertrain housing with an end wall disposed between the powertrain housing and a motor housing. [Figure 3a] FIG. 4 is an enlarged detailed partial view of the bonding area shown in FIG. 3. [Figure 4] FIG. 13 is a longitudinal cross-sectional view of an end wall and a portion of the powertrain without the powertrain housing. [Diagram 5] FIG. 13 is another perspective view of the powertrain housing from a different viewing angle; [Figure 6] FIG. 2 is a side view of the power train housing. [Figure 7] FIG. 7 is a cross-sectional view of the power transmission housing taken along the cutting plane VII-VII shown in FIG. 6.

[0024] In Figure 1 one half of an electrically powered drive axle for a motor vehicle is shown in a schematic view. The axle half shown serves to drive vehicle wheels 2, shown in dashed lines at the left edge of Figure 1, which are rotatably supported on a stub axle 1. A similarly formed second drive axle half is symmetrically located on the other side of the vehicle centre plane M shown in Figure 1 and supports each vehicle wheel on this other vehicle side. The electrically powered drive axle is generally a rigid axle which extends all the way from one vehicle side to the other vehicle side.

[0025] For each vehicle side and thus for driving each vehicle wheel 2, an electric drive 5, in particular an electric motor, is provided near the vehicle centre plane M. Downstream of each electric motor, towards the outside of the vehicle, is a respective transmission 6, which in the illustrated configuration is in the form of a two-stage planetary gear mechanism.

[0026] The two electric drives are located in a common motor housing 3 which may be one piece or made in several parts. Each transmission 6 is located in a transmission housing 4 which is flange-connected to the motor housing 3.

[0027] The transmission housing 4 is composed, inter alia, of a substantially cylindrical housing circumferential wall 11 having an inner surface 7 annularly surrounding the transmission elements of the transmission 6, and of an end wall 12 integral with the housing circumferential wall 11. The end wall 12 is primarily closed, but opens at its center a transmission opening 12a, through which a transmission output shaft 18 of the transmission 6 is guided, which rotates about a central axis of rotation A.

[0028] At its other end, the transmission housing 4 also has an end wall 13. However, this end wall 13 is a separate component. The end wall 13 and the housing circumferential wall 11 are connected to each other in a fluid-tight manner by a circular connecting region 14 which extends over the entire periphery.

[0029] The end wall 13 has a central opening 17 through which an input shaft 19 of a transmission mechanism is guided. The input shaft 19 of the transmission mechanism, which may at the same time be the motor output shaft, also rotates about the axis A.

[0030] The end wall 13 extends radially outwardly from an opening 17 for the transmission input shaft 19 to a connection area 14 in which the end wall 13 and the housing circumferential wall 11 are connected to one another in a fluid-tight manner.

[0031] A transmission output shaft 18 extending beyond the other end wall 12 may be connected, preferably via a spline arrangement, to a drive shaft which is non-rotatably connected to the vehicle wheels 2 and drives these. The drive shaft rotates in a tubular axle housing 15 of the drive unit which also extends about a central axis A. The axle housing 15 is attached to the end wall 12 by means of a flange 16.

[0032] The axle housing 15 is provided at its outer end with a stub axle 1. Furthermore, the brake supports of the vehicle brakes, preferably disc brakes, are mounted on the axle housing 15. Also mounted on the axle housing 15 are the axle guide elements of the vehicle axle, such as longitudinal arms and possibly transverse arms.

[0033] For mounting the axle housing 15 to the powertrain housing 4, the axle housing 15 is provided at its end facing the vehicle with a radially enlarged flange 16. This flange 16 is fixedly screwed to the end wall 12 of the powertrain housing 4 by means of a number of screws 19.

[0034] The motor housing 3, which accommodates the electric drive 5, and the transmission housing 4 are also connected by means of screw fasteners. For this purpose, each end of these housing parts is formed as a radial flange 25, 26. These flanges 25, 26 are rigidly connected to one another via screws guided through axial openings 27 in the flange 26 of the transmission housing 4.

[0035] The power train housing 4 not only has a housing function, but is also part of an epicycloid gear set or a planetary gear set. This is because the inner surface 7 of the housing circumferential wall 11 is provided with a helical tooth arrangement 30a of a first power train stage arranged around the axis of rotation A and a helical tooth arrangement 30b of a second power train stage, which is axially offset and arranged around the axis of rotation A. Each of the two helical tooth arrangements 30a, 30b thus forms an internal gear of the respective planetary gear set. The teeth of the helical tooth arrangement 30b are oriented in the opposite direction to those of the first helical tooth arrangement 30a. The planetary gears of both power train stages of the planetary gear set mesh with the helical tooth arrangement.

[0036] The remaining powertrain elements of the planetary gear mechanism are arranged in a planetary gear support which rotates about axis A. This planetary gear support is inserted into the powertrain housing 4 as a preassembled powertrain support 17c. The central element of the powertrain support 17c is a powertrain output shaft 18 which rotates about axis A. This powertrain output shaft 18 projects beyond a powertrain opening 12a in the powertrain housing 4 which is also centrally located.

[0037] Cooling of the gear train 6 and its partially heavily loaded teeth, pinions and bearings is achieved by a coolant circulated by a pump, preferably a gear train oil, whereby the liquid not only lubricates the gear train elements but also takes care of the heat transport.

[0038] Due to the construction of the planetary gear train, the cooling and lubricating liquid is thrown outwards towards the helical teeth 30a, 30b due to the centrifugal force of the planetary gears. The cooling liquid is therefore collected on the inner surface 7 of the housing circumferential wall 11, along which a pronounced rotation of the liquid occurs at the same time. The liquid can be collected and transported back to the more central areas of the transmission and to the rolling bearing areas, for example the rolling bearings of the transmission input shaft 19 and the transmission output shaft 18, and can be provided again for the cooling and lubrication process.

[0039] The inclined position of both gears 30a, 30b generates, in the case of active circulating cooling, a pumping action on the refrigerant directed towards the end wall 13 in conjunction with the rotation of the power train oil along the inner surface 7. Only in the case of passive sump cooling is the orientation of gear 30b reversed, so that in this case there is also a pumping action directed towards the end wall 12.

[0040] As a result of the rotation of the powertrain oil on the inner surface 7 of the powertrain housing, a strongly flowing oil sump is formed there, which, unless additional measures are taken as explained below, can make it difficult for the lubricant and coolant to escape ideally, because if the powertrain oil passes by the existing oil outlet at high speed instead of flowing completely into it, the resulting flows make it difficult to siphon off the powertrain oil, which is necessary for circulation.

[0041] The solution to this problem consists in providing an annular chamber 33, preferably in a circular shape, surrounding the axis A. This annular chamber 33 extends circumferentially along the connection area 14, where the end wall 13 is attached to the peripheral housing wall 11. It is important that the annular chamber 33 is connected to the inner space 7 of the transmission housing only via individual openings 40. The openings 40 are evenly distributed over the inner circumference of the annular chamber 33.

[0042] The annular chamber 33 serves to calm the coolant flowing at high speeds in other areas of the powertrain housing, in particular the coolant rotating vigorously along the inner wall. The annular chamber 33 therefore has the function of a calming zone for the coolant. This calming zone is open towards the inner space 7 only in a defined circumferential portion, i.e. only in the area of ​​the individual openings 40, so that the coolant or the powertrain oil can flow through these openings 40 into the annular chamber 33 and be calmed there.

[0043] In contrast, in the other circumferential portion, the annular chamber 33 is substantially closed with respect to the powertrain interior 7, so that no significant liquid exchange takes place in this other circumferential portion, and the flow of liquid can be calmed down along the area of ​​the annular chamber 33 closed towards the powertrain interior. The calming of the flow improves the oil suction or oil outflow. This is done through a passage that opens into the annular chamber 33 directly, for example at its lowest point, and allows the liquid to flow downwards into a collector.

[0044] In order for the annular chamber 33 to form a calming zone, the openings 40 and the non-opening circumferential portions 41 are arranged alternately around the circumference of the annular chamber. The number of openings 40 and the number of non-opening circumferential portions 41 are equal, and in this embodiment there are six openings 40 and similarly six non-opening circumferential portions 41 around the entire circumference.

[0045] The diameter of the annular chamber 33 is greater than the largest diameter that the inner surface 7 of the peripheral housing wall 11 has outside the area of ​​the annular chamber 33 .

[0046] An annular chamber 33 extends along the joining area 14 where the end wall 13 is attached to the housing peripheral wall 11, such that the walls of this annular chamber 33 are formed partly by the housing peripheral wall 11 and partly by the end wall 13.

[0047] The annular chamber 33 is bounded by an inner chamber wall 44 towards the interior space 7 and by an outer chamber wall 45 towards the outside of the housing circumferential wall 11. The openings 40 and the non-opening circumferential portion 41 are located within or at the inner chamber wall 44.

[0048] The inner chamber wall 44 is formed in a concave-convex shape in a simple manner in terms of manufacturing. In this case, a number of projections extending parallel to the central axis A form a circumferential portion 41 without an opening, and the circumferential portion between the projections forms the opening 40. When the inner chamber wall 44 is viewed in the radial direction, the projections as well as the circumferential portion 41 without an opening arranged between the projections are formed in a rectangular shape.

[0049] The wall of the annular chamber 33, in the area formed by the peripheral housing wall 11 rather than the end wall 13, is a U-shaped wall forming a groove extending in the circumferential direction of a circle about the axis A and open towards the end wall 13. The length of this groove and of the annular chamber 33 in the direction of the axis A is greater than the maximum width of the annular chamber 33 measured between the inner chamber wall 44 and the outer chamber wall 45.

[0050] The axial extension of the opening 40, i.e. the extension of the opening 40 in the direction of the axis A, is less than the axial extension of the annular chamber 33.

[0051] The non-opening circumferential portion 41 extends axially toward the end wall 13 until it contacts the inner surface 13a of the end wall 13 or to the inner surface 13a of the end wall 13, leaving only a small gap that does not allow any or substantially no liquid exchange.

[0052] The end wall 13 separates the transmission 6 from the electric drive 5. On its side facing the transmission 6, the end wall 13 is provided with a collar 50 which extends orthogonally to the main extension plane of the end wall 13 and serves inter alia as a centering collar. This collar 50 is an integral component of the end wall 13. The collar 50 has an axial length which extends into the annular chamber 33. For centering, the collar 50 radially contacts with its outer surface the outer chamber wall 45 with a sealing element 51 interposed therebetween. In the present embodiment, the axial length of the circumferentially extending centering collar is approximately half the axial extension of the annular chamber 33.

[0053] Since the joining area 14 must be liquid-tight, the collar 50 is in radial contact with the chamber wall 45 via an annular sealing element 51 which fits into a sealing groove provided in the outer surface of the collar 50.

[0054] According to Fig. 3a, the transition between the inner surface 13a of the end wall 13, extending transversely to the central axis A, and the inner surface 50a of the collar 50 is formed as a radius 52, preferably as a 90° radius, with the radius R being 25%-75% of the maximum width of the annular chamber 33 between the inner chamber wall 44 and the outer chamber wall 45. By forming the transition as a radius 52, the flow guidance in the annular chamber 33 is improved.

[0055] A plurality of radially extending holes and passages 60 lead from the annular chamber 33 to the outer surface of the peripheral housing wall 11, and in particular to the outer surface of the flange 26 of the powertrain housing, as the flange 26 is disposed to surround the annular chamber 33.

[0056] One of the radial holes or passages 60 is an oil outlet through which the powertrain oil collected in the annular chamber 33 and allowed to settle therein can flow downwards into a collector. For this reason, this hole or passage is located at the lowest point of the flange 26.

[0057] The further holes or passages 60 serve different functions and purposes in connection with the coolant guidance: they may, for example, accommodate an air bleed valve, an air bleed filter, a measuring plug for detecting the coolant level in the powertrain, a magnetically actuated catcher for metal cuttings collected in the liquid or a temperature sensor for detecting the oil temperature.

[0058] Since the bore or passage 60 is located not in the thinner part of the powertrain housing but in the region of the radially widened flange 26 of the powertrain housing, there is sufficient space in this region for such additional functional components. For example, the outer end of the bore or passage 60 may have a thread for screwing in the respective functional component from the outside.

[0059] The holes or passages 60 are located in a circumferential portion of the flange 26 that does not have any axial openings 27 . [Explanation of symbols]

[0060] 1 stub axle 2 Vehicle Wheels 3 Motor housing 4. Transmission Mechanism Housing 5 Electric drive unit 6 Transmission Mechanism 7. Inside 11 Housing peripheral wall 12 End Wall 12a Transmission mechanism opening 13 End Wall 13a Inner surface of end wall 14 Combined area 15 Axle housing 16 Flange 17 Aperture 17c Power train support 18 Transmission output shaft 19. Power transmission input shaft 25 Flange 26 Flange 27 Axial opening 30a Oblique dentition 30b Oblique dentition 33 Annular Chamber 40 aperture 41 Circumference without opening 44 Inner chamber wall 45 Outer chamber wall 50 colors, centering colors 50a color inner surface 51 Sealing element 52 Rounded part 60 holes, passages A axis, rotation axis M Vehicle centerline R radius

Claims

1. 1. An electric drive unit for a motor vehicle, comprising: an electric drive (5); a transmission (6) arranged in a transmission housing (4) downstream of the electric drive (5) in a power flow direction; means for circulating a coolant in an inner space (7) of the transmission housing (4); and a rotatably arranged input shaft (19) or output shaft (18) of the transmission (6), the transmission housing (4) being composed of a peripheral housing wall (11) annularly surrounding a central axis (A) and an end wall (13), the end wall (13) extending radially outward from an opening (17) for the input shaft (19) or the output shaft (18) to a connection area (14) where the end wall (13) and the peripheral housing wall (11) are connected to each other, 1. The electric drive unit, characterized in that it comprises an annular chamber (33) extending circumferentially along the connection area (14) on the side of the inner chamber (7) relative to the end wall (13), the annular chamber (33) being connected to the inner chamber (7) via respective openings (40).

2. 2. An electric drive unit according to claim 1, characterized in that the openings (40) are arranged uniformly distributed over the inner circumference of the annular chamber (33).

3. 3. An electric drive unit according to claim 1 or 2, characterized in that the openings (40) and the circumferential portions (41) without openings are arranged alternately in the circumferential direction.

4. 4. The electric drive unit according to claim 3, characterized in that the number of said openings (40) and the number of said circumferential portions (41) without openings are each between 6 and 10.

5. 5. An electric drive unit according to claim 1, wherein the walls of the annular chamber (33) are formed partly by the housing circumferential wall (11) and partly by the end wall (13).

6. 6. The electric drive unit according to claim 1, wherein the annular chamber (33) surrounds the central axis (A) in a circular manner and the diameter of the annular chamber (33) is greater than the maximum diameter of the inner surface (7) of the circumferential housing wall (11) outside the area of ​​the annular chamber (33).

7. 7. The electric drive unit according to claim 2, wherein the annular chamber (33) is defined by an inner chamber wall (44) toward the inner space (7) and by an outer chamber wall (45) toward the outside of the housing circumferential wall (11), and the openings (40) and the circumferential portion (41) without openings are formed in the inner chamber wall (44).

8. 8. An electric drive unit according to claim 7, characterized in that the inner chamber wall (44) is formed in a concave-convex manner, with convexities forming the circumferential portion (41) without openings.

9. 9. An electric drive unit according to claim 7 or 8, characterized in that the length of the annular chamber (33) in the axial direction is greater than the maximum width of the annular chamber (33) between the inner chamber wall (44) and the outer chamber wall (45).

10. 10. The electric drive unit according to claim 7, further comprising a plurality of holes or passages (60) in the housing circumferential wall (11), the holes or passages (60) leading from the annular chamber (33) to the outer surface of the housing circumferential wall (11).

11. 11. The electric drive unit according to claim 10, characterized in that the housing circumferential wall (11) is formed as a flange (26) which is radially enlarged compared to the remaining part of the housing circumferential wall (11) so as to surround the annular chamber (33), and the holes or passages (60) lead through the flange (26) to its outer surface.

12. 12. An electric drive unit according to claim 11, characterized in that the flange (26) has axial openings (27) arranged distributed over its entire circumference for receiving a plurality of screws or threaded bolts.

13. 13. The electric drive unit according to claim 7, wherein the end wall (13) comprises a collar (50) extending into the annular chamber (33), and the transition between the radially extending portion of the end wall (13) and the collar (50) is formed as a radius (52), preferably the radius (R) of the radius (52) being 25% to 75% of the maximum width of the annular chamber (33) between the inner chamber wall (44) and the outer chamber wall (45).

14. 6. An electric drive unit according to claim 5, characterized in that the wall of the annular chamber (33) in the area formed by the housing circumferential wall (11) is a U-shaped wall of a groove open towards the end wall (13).

15. 15. The electric drive unit according to claim 14, characterized in that the end wall (13) is provided with a collar (50) extending into the annular chamber (33), the collar (50) contacting one of the walls of the groove, preferably the radially outer wall of the groove.

16. 16. Electric drive unit according to claim 15, characterized in that the collar (50) is in contact with the wall of the groove via at least one annular sealing element (51).

17. 17. Electric drive unit according to claim 16, characterized in that the sealing element (51) is fitted into a sealing groove formed in the collar (50).

18. 18. The electric drive unit according to claim 1, wherein the transmission mechanism (6) is a planetary gear mechanism, the internal gear of which is an inner surface of the housing circumferential wall (11) with a tooth row (30a), the tooth row (30a) being formed as a helical tooth row so that the cooling liquid collected therein is conveyed towards the longitudinal part of the housing circumferential wall (11) having the opening (40).

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