DRIVE UNIT AND VEHICLE WITH A DRIVE UNIT

Abstract

The present disclosure relates to a drive unit (1) with a housing (2) and an electric motor (3) arranged therein. A transmission (8) is coupled to the electric motor (3). At least one oil chamber (15) is arranged in the housing (2), the oil chamber(s) having an oil zone (21) and an air zone (22), where the air zone (22) is flow-connected by way of an inlet opening (36) to a venting channel (35) that leads to a vent (32) such that the inlet opening (36) is arranged in a central area (40) of the housing (2) of the drive unit (1).

Claims

1-11. (canceled)

12. A drive unit (1) comprising: a housing (2); an electric motor (3) arranged in the housing; a transmission (8) coupled to the electric motor (3); and at least one oil chamber (15) arranged in the housing (2), the at least one oil chamber comprising an oil zone (21) and an air zone (22), wherein the air zone (22) is flow-connected to a venting channel (35) by way of at, least one inlet opening (36), wherein the venting channel extends to a vent (32) and the at least one inlet opening (36) is arranged in a central area (40) of the housing (2) of the drive unit (1).

13. The drive unit (1) according to claim 12, wherein the at least one inlet opening (36) is arranged in the housing (2) radially inside an outer periphery of a component (34) that is arranged on a rotor shaft (7) of the electric motor (3) and which co-rotates with the rotor shaft (7).

14. The drive unit (1) according to claim 13, wherein the at least one inlet opening (36) is arranged in the housing (2) adjacent to the rotor shaft (7) mounted in the housing (2).

15. The drive unit (1) according to claim 14, wherein in the assembled condition of the drive unit (1), the at least one inlet opening (36) is arranged above a rotation axis of the rotor shaft (7).

16. The drive unit (1) according to claim 12, wherein an aperture of the at least one inlet opening (36) is directed in a direction opposite to a spray direction of oil.

17. The drive unit (1) according to claim 12, wherein the drive unit (1) comprises at least one further oil chamber (16) arranged in the housing (2), the at least one further oil chamber comprising an oil zone (20) and an air zone (23), wherein the oil zone (20) of the at least further oil chamber and each oil zone (21) of the at least one oil chamber are flow-connected by an overflow channel (18) and the air zone (23) of the at least one further oil chamber and the air zone (22) of the at least one oil chamber are flow-connected by a pressure equalization channel (30).

18. The drive unit (1) according to claim 17, wherein the oil zones (20, 21) are provided at opposite axial end areas of the electric motor (3).

19. The drive unit (1) according to claim 12, wherein the at least one inlet opening (36) is protected against the entry of oil from the oil chamber (15) by a mechanical screen (39).

20. The drive unit (1) according to claim 19, wherein the mechanical screen (39) is in the form of a membrane permeable to air but impermeable to oil.

21. The drive unit (1) according to claim 19, wherein the mechanical screen (39) is in the form of a screen wall in the oil chamber (15).

22. The drive unit (1) according to claim 12, wherein in a central area (40) of the housing (2) of the drive unit (1), there is arranged at least one further inlet opening (37) which is offset relative to the first inlet opening (36).

23. A vehicle comprising a drive unit (1) according to claim 12.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Further features and advantages of the invention emerge from the following description of preferred embodiments, with reference to the figures, which show:

[0023] FIG. 1: A sectioned view of an embodiment of the drive unit according to the invention, in which an inlet opening in flow connection with a venting channel is arranged in a central area of the housing of the drive unit, and

[0024] FIG. 2: A front view of an embodiment of the drive unit according to the invention, in which a number of possibilities for the location of the inlet opening of the vent are shown.

DETAILED DESCRIPTION

[0025] FIG. 1 shows a drive unit 1 according to the invention with a housing 2 and an electric motor 3 in a partitioned and sealed motor space 5 arranged in the housing 2. The electric motor 3 can for example be an asynchronous motor with a stator and a rotor.

[0026] In the example embodiment shown, the rotor shaft 7 is in the form of a hollow shaft. Coupled to the rotor shaft 7 is a transmission 8, which in this case is in the form of a planetary transmission. However, other types of electric motors and transmissions can also be used in the drive unit 1.

[0027] The rotor shaft 7 is supported in the housing by means of bearings 9. In the example embodiment shown, the bearings 9 are in the form of ball bearings.

[0028] The planetary wheels 10 of the transmission 8 are supported by bearings 11 on a planetary carrier 12. In contrast, in this example embodiment the bearings 11 of the planetary wheels 10 are in the form of needle bearings.

[0029] The rotor shaft 7 can be driven by the electric motor 3 and in the embodiment shown transmits the torque to a sun gear 13 of the transmission 8. The drive output takes place by way of the planetary carrier 12.

[0030] A pump 14 is arranged on the outside of the housing 2. This pump 14 is an oil pump.

[0031] Two oil chambers 15, 16 are arranged in the housing 2. However, depending on the drive unit there may also be more than two oil chambers. These oil chambers 15, 16 are separated from one another by a partition wall 17 and are flow-connected with one another by an overflow channel 18, here represented symbolically. Furthermore, the oil chambers 15, 16 are separated from the motor space 5 of the electric motor 3 by seals 19.

[0032] In this case the oil chambers 15, 16 are located in the axial end areas of the electric motor 3, where the bearings 9, 11 and the transmission 8 are also arranged. The overflow channel 18 forms a flow connection between the oil chambers 15, 16.

[0033] In each case, in the assembled condition the oil chambers 15, 16 have respective oil zones 20 and 21 at the bottom and air zones 22, 23 above them.

[0034] In the assembled condition, owing to a slightly oblique position of the drive unit 1 in the vehicle the oil zone 20 of the oil chamber 16 is approximately vertically under the oil chamber 15 and therefore has the function of a primary oil reservoir.

[0035] In the example embodiment shown, the pump 14 draws oil out of this oil zone 20 of the oil chamber 16 by way of a dedicated suction channel 24 that begins in the oil chamber 16. The suction channel 24 is a separate channel a distance away from the overflow channel 18 and leads to the pump 14 directly alongside the oil, chamber 15.

[0036] The pump 14 delivers the oil into a channel 25 inside the rotor shaft 7, which the latter is for that purpose made as a hollow shaft. The two oil chambers 15, 16 are additionally connected with one another by way of this channel 25.

[0037] From the channel 25 an opening 26 leads to the bearing 9 in the oil chamber 15, so that oil is delivered to the appropriate bearing and lubricates and cools it. Oil flowing out of the bearing, 9 is then already in the oil chamber 15 and can flow into its oil zone 21.

[0038] At the opposite end of the rotor shaft 7 a further opening 27 is provided, through which oil can flow on the one hand to the bearing 9 in the oil chamber 16 and on the other hand to the planetary wheels 10 and thus also to the sun gear 13 and, via openings 28, to the bearings 11 of the planetary wheels 10. The teeth meshing with a ring gear 29 of the planetary transmission are also lubricated thereby.

[0039] In this case too, the oil in the oil chamber 16 can flow down into the oil zone 20. From there it is again drawn off by the pump 14, so that a circuit is produced.

[0040] In the embodiment shown in FIG. 1 a pressure equalization channel 30 is provided, which forms a flow connection between the air zones 22, 23 of the two oil chambers 15, 16. The pressure equalization channel 30 is shown as a broken line and extends completely inside the housing 2, and can in this case be in the form of a tube or flexible pipe. If necessary, the tube or pipe can pass through the overflow channel 18 without restricting its cross-section too much.

[0041] The ends and therefore outlet points 31 of the pressure equalization channel 30 open into the air zones 22, 23 of the oil chambers 15, 16 and thus ensure pressure equalization between the oil chambers 15, 16. The outlet points 31 of the pressure equalization channel 30 are provided with a symbolically represented mechanical screen 33, which prevents the oil from making its way into the pressure equalization channel 30. The mechanical screen can, for example, be in the form of a membrane which is permeable to air but impermeable to oil. Such a membrane can be arranged at the ends of the pressure equalization channel 30. Thus, air can enter the pressure equalization channel 30 and ensure pressure equalization, but oil is held back by the membrane.

[0042] It is also conceivable to make the mechanical screening 33 in the form of a labyrinth-type screen wall. Such a screen wall can for example be arranged directly at the outlet points 31 of the pressure equalization channel 30 or it can be part of the wall of the housing 2. The labyrinth structure prevents oil from getting into the pressure equalization channel 30, whereas air can pass through such a labyrinth screen and thus ensure pressure equalization between the oil chambers 15, 16.

[0043] If such a pressure equalization channel 30 is used, vents do not have to be provided for both oil chambers 15, 16. It is sufficient for one of the two oil chambers 15, 16 to be provided with a vent 32. In this case the vent 32 is flow-connected to the corresponding oil chamber 15 via a venting channel 35 which opens into an inlet opening 36 in one of the air zones 22. The venting channel 35 can be formed in the housing 2 of the drive unit 1. The vent 32 leads to the open air.

[0044] Thus, a transition is formed between the air zone 22 of the oil chamber 15 and the venting channel 35 by way of the at least one inlet opening 36. It is provided that the at least one inlet opening 36 flow-connected to the venting channel 35 is arranged in a central area of the housing 2 of the drive unit 1.

[0045] The inlet opening 36 of the venting channel 35 is provided in the housing 2 of the drive unit 1 radially inside an outer periphery of the impulse ring 34 arranged on the rotor shaft 7. Moreover, the inlet opening 36 is arranged adjacent to the rotor shaft 7 mounted in the housing 2 or adjacent to the bearing 9 that supports the rotor shaft 7 in the housing 2 of the drive unit 1. This enables the inlet opening 36 to be positioned as close as possible to the center in the housing 2 of the drive unit 1.

[0046] The positioning of the at least one inlet opening 36 in a central area of the housing 2 of the drive unit 1 avoids the spraying of oil, during the rotation of the rotor shaft 7, into the inlet opening 36 by an impulse ring 34 arranged on the rotor shaft 7, and thereby blocking the said opening. Rather, the inlet opening 36 remains free from oil, thus ensuring the veining of the oil chambers 15, 16.

[0047] The inlet opening 36 of the venting channel 35 is provided with a symbolically represented mechanical screen 39, which prevents the oil from making its way into the venting channel 35. The mechanical screen 39 can for example be in the form of a membrane permeable to air but impermeable to oil. Such a membrane can, for example, be arranged at the end of the venting channel 35. Thus, air can get through the venting channel 35 and ensure venting or aeration of the oil chamber 15, but oil is held back by the membrane.

[0048] It is also conceivable that the mechanical screen 39 is made as a labyrinth-type screen wall. Such a screen wall can for example be arranged directly over the inlet opening 36 of the venting channel 35, or can be part of the wall of the housing 2. The labyrinthine structure prevents oil from getting into the venting channel 35, whereas air can pass through such a labyrinthine screen and so ensure venting or aeration of the oil chamber 15.

[0049] In the embodiment shown in FIG. 2 the inlet opening 36, which is in flow connection with the vent 32 by way of the venting channel 35, is positioned in a central area 40 of the housing 2. In this case the inlet opening 36 connects the air zone 22 of the oil chamber 15 via the venting channel 35 to the vent 32, in order to ensure venting and aeration of the oil chamber 15. In these examples several possible positions for the inlet opening 36 are shown. Furthermore, for the sake of greater visibility a cover positioned laterally on the housing 2 is not shown.

[0050] In this case the central area 40 is indicated by two concentric broken circles and is essentially formed by the annular area between them, in which the inlet opening 36 can be positioned as close as possible to the center of the housing 2 and away from the outer edge of an impulse ring 34 that serves for the measurement of rotation speed. Toward the center the said central area 40 is delimited by the rotor shaft 7 and the associated bearing 9.

[0051] The inlet opening 36 is preferably located in the upper half of the central area 40 since in the lower area, depending on the operating condition, oil may be present. Accordingly; the venting channel 35 can then be made shorter.

[0052] Location of the inlet opening 36 at the indicated points in the central area 40 has the advantage that in those positions the inlet opening 36 can be blocked by oil only with difficulty, since the impulse ring 34 will spray the oil outward. The oil then collects on the cover (not shown here) and runs back down into the oil zone 21.

[0053] Furthermore, the inlet opening 36 can be designed such that the aperture of the inlet opening 36 is directed away from the oil-spraying action of the impulse ring 34, so that the oil cannot be sprayed directly through the inlet opening 36 into the venting channel 35.

[0054] In FIG. 2, in addition to the at least one inlet opening 36 at least one further inlet opening 37 is shown. This further inlet opening 37 is also located in the central area 40 of the housing 2 of the drive unit 1. In that way, the air zone 22 of the oil chamber 15 is flow-connected to the venting channel 35 by way of this further inlet opening 37 as well. A transition between the air zone 22 and the venting channel 35 is therefore also formed by the said further inlet opening 37. Like the inlet opening 36, so too the inlet opening 37 can be provided with a mechanical screen that prevents oil from making its way into the venting channel 15. In the central area 40 the two inlet openings 36, 37 are arranged offset relative to one another. In the central area 40, in the assembled condition of the drive unit 1 the first inlet opening 36 can be arranged in an area preferably between nine and eleven o'clock, whereas the second inlet opening 37 is arranged in an area between one and three o'clock. In FIG. 2, as examples two possible positions for the inlet opening 36 and two possible positions for the inlet opening 37 are shown. In that way, the venting of the oil chamber 15 is ensured regardless of the rotation direction of the rotor shaft 7 of the electric motor 3. If the rotor shaft 7 is rotating clockwise, venting of the oil chamber 15 can be ensured through the inlet opening 37 which is positioned away from the oil spraying action. If the rotor shaft 7 is rotating in the counter-clockwise direction, then in contrast the venting of the oil chamber 15 is ensured through the inlet opening 36. Thus, venting of the oil chamber 15 is ensured even if sprayed oil should get through the rotating rotor shaft 7 to the central area 40. Accordingly, venting is independent of the travel direction of the vehicle propelled by the drive unit 1.

INDEXES

[0055] 1 Drive unit [0056] 2 Housing [0057] 3 Electric motor [0058] 5 Motor space [0059] 7 Rotor shaft [0060] 8 Transmission [0061] 9 Bearing [0062] 10 Planetary wheels [0063] 11 Bearing [0064] 12 Planetary carrier [0065] 13 Sun gear [0066] 14 Pump [0067] 15 Oil chamber [0068] 16 Oil chamber [0069] 17 Partition wall [0070] 18 Overflow channel [0071] 19 Seals [0072] 20 Oil zone [0073] 21 Oil zone [0074] 22 Air zones [0075] 23 Air zone [0076] 24 Suction channel [0077] 25 Channel [0078] 26 Opening [0079] 27 Opening [0080] 28 Openings [0081] 29 Ring gear [0082] 30 Pressure equalization channel [0083] 31 Outlet points [0084] 32 Vent [0085] 33 Screen [0086] 34 Impulse ring [0087] 35 Venting channel [0088] 36 Inlet opening [0089] 37 Inlet opening [0090] 39 Screen [0091] 40 Central area