Electric drive device for a vehicle

Abstract

An electric drive for a vehicle having a housing, an electric machine, a transmission, and a hydraulic circuit for circulating fluid to cool and lubricate the electric machine and the transmission.

Description

Technical Field

[0001] The present invention relates to an electric drive device for a vehicle, which has a housing, an electric machine, a transmission, and a hydraulic circuit for circulating a fluid to cool and lubricate the electric machine and the transmission.

[0002] From US Patent Application Publication No. 2019 / 0229582, a lubrication path including a first oil pump that pumps up oil stored in a casing by the first oil pump and supplies the power transmission mechanism to lubricate the power transmission mechanism, and a cooling path provided in a rotating electric machine separated from the lubrication path, which pumps up oil stored in the casing by the second oil pump and supplies only the rotating electric machine to cool the rotating electric machine. A second oil pump, and an oil cooler for cooling the oil supplied to the rotating electric machine is provided in the cooling path. A vehicle drive device is known.

[0003] From International Publication No. 2020 / 069744, an electric drive device for driving an automobile having a housing device, an electric machine, a planetary unit, and a power transmission unit is known. The housing device has a first housing portion on the motor side, a second housing portion on the transmission side, and an intermediate housing portion that separates the motor space and the transmission space from each other. The intermediate housing member has a motor-side casing portion extending axially within the outer casing portion of the first housing member and a transmission-side casing portion extending axially within the second housing member. A sealed space for circulating a coolant is formed between the outer surface of the motor-side casing portion and the inner surface of the first housing portion.

[0004] International Publication No. WO 2015 / 058788 discloses a drive assembly for an automobile having a first gear and a second gear, with the first gear and the second gear being drivingly connected to each other, and a lubricant charge that defines a lubricant level in a static installed state of the drive assembly. A first reservoir is disposed above a lubricant level that can be filled with lubricant as a result of rotation of the first gear. A second reservoir is disposed above a lubricant level that can be filled with lubricant as a result of rotation of the second gear. The first reservoir functions to lubricate a first bearing region, and the second reservoir functions to lubricate a second bearing region of the drive assembly.

[0005] U.S. Patent Application Publication No. 2018 / 241288 discloses a cooling structure for a rotating electrical machine that cools a stator and a rotor of the rotating electrical machine by supplying a cooling medium to the stator and the rotor by a pump, the cooling structure including a first passage that supplies the cooling medium from the pump to the stator, a second passage that supplies the cooling medium from the pump to the rotor, and a valve that adjusts a flow of the cooling medium in the first passage and a flow of the cooling medium in the second passage, wherein a cooling state of the stator and a cooling state of the rotor are controlled by the valve.

[0006] U.S. Patent No. 10,272,767 discloses an electric drive train system, which includes an electric drive train of an electric vehicle. The electric drive train includes an inverter component, a gearbox component, and a motor component. A first cooling system uses ethylene glycol and an aqueous coolant (EGW). The first cooling system includes an EGW coolant loop for distributing coolant through at least one of the inverter component, the housing of the gearbox component, and the housing of the motor component to remove heat from the inverter component, the housing of the gearbox component, and the housing of the motor component. A second cooling system uses an oil-based coolant. The second cooling system includes an oil-based coolant loop for distributing the oil-based coolant through at least one of the internal components of the gearbox component and the internal components of the motor component to remove heat from at least the internal components of the gearbox component and at least the internal components of the motor component. An oil coolant pump controls the flow of the oil-based coolant through the oil-based coolant loop, and a heat exchanger transfers heat from the oil-based coolant loop to the EGW coolant loop, away from the electric drive train, to a vehicle cooling system having a radiator.

[0007] European Patent Application Publication No. 3,517,335 discloses an electric vehicle including a power control unit, a drive motor, a first cooling channel with a first pump attached thereto for flowing a first coolant cooled in a first heat exchanger through the power control unit and a second heat exchanger in this order and then back to the first heat exchanger, and a second cooling channel with a second pump attached thereto for flowing a second coolant cooled by the first coolant in the second heat exchanger through the drive motor and then back to the second heat exchanger. The second pump starts or stops the circulation of the second coolant, or increases or decreases the circulation amount of the second coolant based on one or both of the temperature of the power control unit and the temperature of the first coolant.

[0008] The electric machine and transmission of an electric drive device for a vehicle have different cooling and lubrication requirements depending on the operating conditions. The performance of the electric machine is thermally limited during operation. There may be inherent losses in the copper, iron, and magnets of the electric motor, and the temperature of each component and structure is limited by the material properties. Effective cooling is necessary to achieve sufficient torque performance. The passive splash lubrication of the transmission causes churning losses under high-speed operation. The combination of cooling and lubrication for both the electric machine and the transmission is a compromise in terms of efficiency.

[0009] Therefore, an object of the present invention is to propose an electric drive device for a vehicle having a hydraulic circuit for circulating a fluid for efficient cooling and lubrication of an electric machine and a transmission.

[0010] This object is achieved by an electric drive device for a vehicle, the electric drive device comprising: a housing; an electric machine including a stator connected to the housing and including a stator end winding, and a rotor including a rotor shaft rotatably supported within the housing; a transmission that transmits the rotational movement from the rotor shaft to drive the vehicle's driveline; a hydraulic circuit for circulating a fluid to cool and lubricate the electric machine and the transmission; and wherein the hydraulic circuit comprises: an oil sump formed at the lower part of the housing; a reservoir disposed above the oil sump and configured to temporarily store oil and supply it to the rotating parts of the transmission; a bi-directional pump hydraulically connected to the oil sump on the suction side, further hydraulically connected to the reservoir on the first pressure side, and hydraulically connected to the cooling nozzles of the electric machine on the second pressure side; which is solved by the electric drive device.

[0011] When the bidirectional pump operates in the first rotational direction, fluid is supplied to the reservoir, and when the bidirectional pump operates in the second rotational direction, fluid is supplied to the cooling nozzles to cool the stator end windings.

[0012] The advantage of the electric drive device is that by switching between the first rotational direction and the second rotational direction, the bidirectional pump of the hydraulic circuit can be operated to optimize the cooling and lubrication of the electromechanical machine and the transmission according to the actual cooling and lubrication requirements. The first rotational direction can advantageously be applied to high-speed operation of the vehicle and thus to high rotational speeds of the rotor and transmission components. During high-speed operation, since the torque requirement of the electromechanical machine is low, spray cooling of the winding head via the cooling nozzles is not necessary. Instead, lubrication of the transmission components rotating at high speed can advantageously be achieved by the fluid supplied to the reservoir. For example, the final drive of the transmission can still be passively splash-lubricated. By reducing the oil level in the oil sump, churning losses are advantageously reduced.

[0013] The second rotational direction can advantageously be applied to low-speed operation of the vehicle and thus to low rotational speeds of the rotor and transmission components compared to high-speed mode. High torque requirements are common during low-speed operation, and due to high currents causing copper losses, the stator end windings are advantageously cooled by the fluid supplied to the cooling nozzles, and thus the losses can be reduced. High-pressure spray cooling of the winding head is possible when the bidirectional pump operates in the second rotational direction, while lubrication of the transmission in low-speed mode does not require an active fluid supply. Passive splash lubrication of the transmission is effective under low-speed conditions because churning losses are lower due to the low rotational speed.

[0014] The fluid circulating within the hydraulic circuit is a cooling and lubricating fluid such as, for example, oil. The oil sample is arranged to collect the fluid dripping from the electromechanical device and the transmission by gravity, and this fluid is not limited to an oily cooling and lubricating fluid despite the expression "oil sample".

[0015] According to one embodiment, the bidirectional pump is hydraulically connected to the inner diameter portion of the drive shaft and / or the transmission via a reservoir, and when the bidirectional pump is operated in the first rotational direction, fluid is supplied to the inner diameter portion of the drive shaft and / or the transmission. Active lubrication of the transmission does not require a high-pressure fluid supply under high-speed conditions, and for the electromechanical device, advantageously, a low-pressure coolant fluid can be supplied, for example, via the drive shaft, such as via a radial bore of the drive shaft connecting the inner diameter portion to the rotor. The rotor is cooled and the fluid is further centrifuged towards the stator, thus also cooling the stator end windings.

[0016] According to a further embodiment, the bidirectional pump is hydraulically connected to a heat exchanger on the first pressure side and / or the second pressure side in order to cool the fluid. The heat exchanger is, for example, a fluid / water heat exchanger. The first pressure side and the second pressure side may be hydraulically separated and each connected to the heat exchanger. Note that the two heat exchangers may be arranged as one integral part.

[0017] Alternatively, the first pressure side and the second pressure side can also be hydraulically connected at a pressure side junction upstream of a single heat exchanger. Reverse flow of fluid between the first pressure side and the second pressure side is avoided by a check valve disposed between the bidirectional pump and the pressure side junction. According to a further embodiment, the hydraulic circuit comprises a mode control valve hydraulically connected to the bidirectional pump at the first pressure side and the second pressure side, a hydraulic stator path connecting the mode control valve to the cooling nozzle, and a hydraulic transfer path connecting the mode control valve to the reservoir. Thus, the bidirectional pump is hydraulically connected to the reservoir via the mode control valve at the first pressure side and hydraulically connected to the cooling nozzle via the mode control valve at the second pressure side.

[0018] According to a further embodiment, the mode control valve is a 3-port 2-position valve that can be hydraulically actuated via a pressure line hydraulically connected to the bidirectional pump at the first pressure side. When the bidirectional pump is operated in the first rotational direction, the first pressure side is pressurized to a first pressure level, whereby the mode control valve is operated so that the bidirectional pump is hydraulically connected to the reservoir at the first pressure side. A pressure control valve is disposed downstream of the hydraulic line branch, and this pressure control valve causes the mode control valve to be actuated by the pressure formed before opening and enabling the flow of fluid from the first pressure side to the mode control valve. When the bidirectional pump is operated in the second rotational direction, the second pressure side is pressurized to a second pressure level and the previous first pressure side becomes the suction side of the bidirectional pump. The pressure in the pressure line drops and the valve returns to its non-operated position, which can be achieved by a biasing spring so that the bidirectional pump is hydraulically connected to the cooling nozzle at the second pressure side.

[0019] When the bidirectional pump is operated in the first rotational direction, the first pressure side is pressurized to a first pressure level to supply fluid for active cooling of the rotor and active lubrication of the transmission, and the liquid level in the oil sump is advantageously reduced by supplying fluid to the reservoir. When the bidirectional pump is operated in the second rotational direction, the second pressure side is pressurized to a second pressure level higher than the first pressure level at which fluid is supplied to the cooling nozzle, while the liquid level in the oil sump rises. According to a further embodiment, the reservoir is hydraulically connected to the oil sump, and when the bidirectional pump is operated in the second rotational direction, the fluid flows from the reservoir back to the oil sump.

[0020] According to a further embodiment, the reservoir is arranged inside the housing. According to an alternative embodiment, the reservoir is arranged outside the housing. The reservoir can be arranged at least partially radially above the rotor shaft.

[0021] According to a further embodiment, the electric drive device can comprise a cooling device for cooling the fluid, which is hydraulically connected to the suction side of the bidirectional pump. Since the non-active first pressure side or the second pressure side of the bidirectional pump becomes the suction side each time, the first pressure side and the second pressure side are connected at a suction side junction upstream of the bidirectional pump that can be connected to the cooling device. A check valve is arranged between the bidirectional pump and the junction to prevent backflow from the active first pressure side or the second pressure side to the suction side each time. The cooling device comprises - an inner casing part and an outer casing part of the housing forming a casing cooling structure through which an aqueous coolant flows, - a housing shield arranged radially outside the outer casing part and at least partially below the rotational axis of the rotor, thereby forming a shield cooling structure through which fluid can flow towards the oil sump and comprising.

[0022] The casing cooling structure containing a coolant is hydraulically separated from the shield cooling structure for the fluid, thereby providing heat exchange between the coolant and the fluid.

[0023] The shield cooling structure, which is arranged radially outside the casing cooling structure and at least partially surrounds the casing cooling structure, advantageously enables heat exchange between the aqueous coolant flowing through the casing cooling structure and the fluid flowing through the shield cooling structure. In this way, an additional suction-side heat exchanger for cooling the fluid is provided, resulting in more effective cooling of the fluid. The shield cooling structure arranged below the rotational axis of the rotor enables the collection of the fluid used for cooling the rotor and the winding head. The following expressions should be understood with reference to the direction of gravity when the electric drive device is in an operable installation state. Thus, the housing shield can be arranged radially between the outer casing part and the oil sump. The housing shield covers, for example, a sector of at least 45° in the circumferential direction of the rotational axis of the rotor.

[0024] To further improve the heat exchange of the cooling device, the shield cooling structure can be provided with channels extending substantially parallel to the axial direction. The channels advantageously provide a larger surface area and thus improved heat transfer from the fluid to the shield cooling structure. Furthermore, the channels enable the use of both axial flow directions. Generally, the shield cooling structure can have a downward inclination to provide the flow of the fluid due to gravity, and the fluid flows, for example, into the oil sump from the shield cooling structure towards the outlet passage. Each channel may similarly have a downward inclination. The shield cooling structure can further be provided with fins connected to the outer cooling casing and / or the housing shield. The fins also provide a larger surface area and thus improved heat transfer from the fluid to the shield cooling structure.

[0025] Exemplary embodiments and further advantages of an electric drive device for a vehicle will be described below with reference to the accompanying drawings.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

[0027] Figure 1 shows an electric drive device for a vehicle, with the housing 1, the electric machine 2, the transmission 3, the oil sump 4 and the reservoir 5 shown as a schematic longitudinal cross-section along the axis of rotation A of the rotor 10 of the electric machine 2. The electric machine 2 has a stator 9 connected to the housing 1 and including a stator end winding 31, and a rotor 10 rotatable relative to the stator 9. A drive shaft 11 is connected to the rotor 10, and this drive shaft 11 is rotatably supported in the housing 1 about the axis of rotation A. The transmission 3 is adapted to transmit the rotational movement from the drive shaft 11 and drive a vehicle drive line (not shown). The transmission 3 can include, for example, a reduction gear (not shown), a differential drive, and a coupling. A hydraulic circuit 7 for circulating fluid to cool and lubricate the electric machine 2 and the transmission 3 is partially and schematically shown. The hydraulic circuit 7 includes an oil sump 4 formed in the lower part of the housing 1, a reservoir 5 arranged above the oil sump 4 and configured to temporarily store fluid and supply it to the rotating parts of the transmission 3, and a bidirectional pump 24 hydraulically connected to the oil sump 4 on the suction side via a fluid supply line 20. The bidirectional pump 24 is further hydraulically connected to the reservoir 5 on the first pressure side 22 and to the cooling nozzle 33 of the electric machine 2 on the second pressure side 26. When the bidirectional pump 24 is operated in the first rotational direction, fluid is supplied to the reservoir 5, and when the bidirectional pump 24 is operated in the second rotational direction, fluid is supplied to the cooling nozzle 33 to cool the stator end winding 31. The bidirectional pump 24 is further hydraulically connected to the inner diameter portion 18 of the drive shaft 11 and the transmission 3 via the reservoir 5. When the bidirectional pump 24 is operated in the first rotational direction, fluid is further supplied to the inner diameter portion 18 of the drive shaft 11 and the transmission 3. In the illustrated embodiment, the reservoir 5 arranged in the housing 1 on the transmission side has an outlet 8 for supplying fluid to the bearings and gears of the transmission 3 and to the rotor 10 via the inner diameter portion 18 of the drive shaft 11.The fluid is introduced through the radial bore 21 of the drive shaft 11 that connects the inner diameter portion 18 to the rotor 10. The fluid is centrifuged along the rotor 10 towards the stator 9 and flows back to the oil sump 4 by gravity as indicated by the arrow F.

[0028] The housing 1 includes an intermediate wall 16 that separates the oil sump 4 on the motor side of the housing 1 from the transmission sump 6 on the transmission side of the housing 1. The passage 37 within the intermediate wall 16 allows the fluid dripping from the transmission 3 to flow into the machine side reservoir 5 as indicated by the arrow F. The liquid level within the transmission sump 6 can be made higher during low-speed operation to provide adequate splash lubrication, while during high-speed operation, the liquid level within the transmission sump 6 is reduced to keep churning losses low.

[0029] The mode control valve 12 is hydraulically connected to both the first pressure side 22 and the second pressure side 26 of the bidirectional pump 24, and the first pressure side 22 and the second pressure side 26 merge at a junction point 28 downstream of the bidirectional pump 24. The check valve device 29 prevents the flow of fluid from the active side to the non-active side of each of the first pressure side 22 and the second pressure side 26. In this embodiment, the mode control valve 12 is hydraulically actuated via a pressure line 30 that is hydraulically connected to the bidirectional pump 24 at the first pressure side 22. Thus, depending on the rotational direction of the bidirectional pump 24, the mode control valve 12 is actuated between its two positions. When the bidirectional pump 24 is actuated in the first rotational direction, the mode control valve 12 is actuated to the first position by the pressure in the pressure line 30. The downstream check valve of the check valve device 29 on the first pressure side 22 is biased toward its closed position by a check valve spring 39, and the check valve spring 39 is adapted to maintain the check valve in a closed state when the first pressure side 22 becomes the active side, allowing pressure to accumulate in the pressure line 30. In the first position, the hydraulic transmission path 15 that connects the mode control valve 12 to the reservoir 5 is hydraulically connected to the bidirectional pump 24 at the first pressure side 22. When the bidirectional pump 24 is actuated in the second rotational direction, the mode control valve 12 is not pressurized and is thus actuated to the second position by a return spring 32. In the second position, the hydraulic stator path 14 that connects the mode control valve 12 to the cooling nozzle 33 is hydraulically connected to the bidirectional pump 24 at the second pressure side 26.

[0030] The two rotational directions of the bidirectional pump 24 provide two modes of the hydraulic circuit 7 for optimized cooling and lubrication of the electromechanical machine 2 and the transmission 3, depending on the operating conditions of the electric drive device. The bidirectional pump 24 is driven by an electric motor 34. A suction filter 25 is arranged in the fluid supply line 20 upstream of the bidirectional pump 24. Downstream of the suction filter 25, the fluid supply line 20 is split into two branches at the suction side junction point 27, which are connected to the first pressure side 22 and the second pressure side 26 of the bidirectional pump 24, respectively. Since the respective non-active first pressure side 22 or second pressure side 26 of the bidirectional pump 24 becomes the suction side of the bidirectional pump 24, a reverse flow of fluid from the respective active first pressure side 22 or second pressure side 26 to the suction side is avoided by a check valve 29 arranged between the bidirectional pump 24 and the suction side junction point 27. At the first pressure side 22 and the second pressure side 26 of the bidirectional pump 24, the fluid is cooled in a heat exchanger 35 arranged upstream of the mode control valve 12.

[0031] Next, an embodiment of the electric drive device will be further described with reference to FIG. 2. FIG. 2 shows the electric drive device of FIG. 1 in which the bi-directional pump 24 is operating in the first rotational direction. By reversing the pumping direction of the bi-directional pump 24 to the first rotational direction, the hydraulic circuit 7 provides lubricating and cooling fluid optimized for the high-speed operation of the electromechanical 2. The downstream check valve 29 on the first pressure side 22 is biased towards its closed position by the check valve spring 39, and the check valve spring 39 is adapted to keep the check valve 29 closed at the moment the pumping direction is reversed and accumulate pressure in the pressure line 30. By pressurizing the first pressure side 22, the mode control valve 12 is actuated via the pressure line 30 against the biasing force of the return spring 32. The mode control valve 12 directs the fluid flow into the hydraulic transmission path 15. The check valve 29 establishes the fluid flow into the hydraulic transmission path 15 from the supply line 20 through the bi-directional pump 24 towards the first pressure side 22, which flow is indicated by the solid line, while the dotted line indicates the non-active line. In general, intersecting lines are not connected unless otherwise stated or indicated by a dot. The first pressure side 22 is pressurized to the first pressure level to supply fluid for the active cooling of the rotor 10 and the active lubrication of the transmission 3. By supplying fluid to the reservoir 5, a high liquid level 38 in the reservoir 5 is shown, while the liquid level 36 in the transmission sump 6 decreases.

[0032] Next, an embodiment of the electric drive device will be further described with reference to FIG. 3. FIG. 3 shows the electric drive device of FIG. 1 in which the bi-directional pump 24 is operating in the second rotational direction. The second pressure side 26 is pressurized to a second pressure level higher than the first pressure level to supply fluid to the cooling nozzle 33, while the liquid level 36 in the transmission sump 6 rises, for example, to the liquid level in the oil sump 4. The reservoir 5 is hydraulically connected to the oil sump 4 to allow fluid to flow from the reservoir 5 back to the oil sump 4, resulting in a corresponding liquid level 38 in the reservoir 5. Since the first pressure side 22 forms the suction side of the bi-directional pump 24, the hydraulic line 30 is not pressurized by the bi-directional pump 24. Accordingly, the mode control valve 12 is actuated towards its second position by the return spring 32. The check valve 29 establishes a fluid flow from the supply line 20 through the bi-directional pump 24 towards the second pressure side 26 and further into the hydraulic stator path 14. The fluid is supplied to the cooling nozzle 33, which sprays the fluid onto the winding head 31 of the stator 9. From the stator 9, the fluid flows downwards towards the oil sump 4 by gravity, as indicated by the arrow F. The hydraulic transmission path 15 is not pressurized and the fluid is splash lubricated from the transmission sump 6 without being actively transported to the transmission 3, which is sufficient for low-speed operation of the vehicle, i.e., the low rotational speed of the rotor 10 and the rotating parts of the transmission 3.

[0033] FIG. 4 shows a further exemplary embodiment of the electric drive device in a schematic diagram similar to the embodiment of FIG. 1. Similar parts are denoted by similar reference numerals. The electric drive device according to this embodiment comprises a housing 1, an electric machine 2, a transmission 3, and an oil sump 4, which will not be repeatedly described in detail herein. Refer to the above description.

[0034] However, the reservoir 5 is arranged outside the housing 1. A hydraulic circuit 7 for circulating fluid to cool and lubricate the electromechanical machine 2 and the transmission 3 includes an oil sump 4 formed at the lower part of the housing 1 and an external reservoir 5 arranged above the oil sump 4. The external reservoir 5 is configured to temporarily store fluid and supply the fluid to the rotating parts of the transmission 3. The bidirectional pump 24 is hydraulically connected to the oil sump 4 on the suction side via a fluid supply line 20. The bidirectional pump 24 is further hydraulically connected to the external reservoir 5 on the first pressure side 22 and to the cooling nozzle 33 of the electromechanical machine 2 on the second pressure side 26. When the bidirectional pump 24 operates in the first rotation direction, fluid is supplied to the external reservoir 5, and when the bidirectional pump 24 operates in the second rotation direction, fluid is supplied to the cooling nozzle 33 to cool the stator end winding 31. The bidirectional pump 24 is further hydraulically connected to the inner diameter portion 18 of the drive shaft 11 and the transmission 3 via the external reservoir 5 and a conduit 17. In the illustrated embodiment, fluid is supplied from the external reservoir 5 through the conduit 17 to the bearings and gears of the transmission 3 and to the rotor 10 through the inner diameter portion 18 of the drive shaft 11. The liquid level 36 in the oil sump 4 is indicated by two dashed lines. The lower liquid level 36 appears when the bidirectional pump 24 is operating in the first rotation direction, and the higher liquid level 36 appears when the bidirectional pump 24 is operating in the second rotation direction.

[0035] FIG. 5 shows a further exemplary embodiment of the electric drive device in a schematic diagram similar to the embodiment of FIG. 4. In FIG. 6, the embodiment of FIG. 5 is shown in a schematic cross-sectional view through the housing 1 in the axial direction of the electromechanical machine 2, and the components of the electromechanical machine 2 are not shown. FIGS. 5 and 6 will be described together. Similar components are denoted by similar reference numerals. The electric drive device according to this embodiment includes a housing 1, an electromechanical machine 2, a transmission 3, an oil sump 4, and an external reservoir 5, but these will not be repeatedly described in detail. Refer to the above description.

[0036] A hydraulic circuit 7 for circulating fluid to cool and lubricate the electromechanical machine 2 and the transmission 3 includes an oil sump 4 formed in the lower part of the housing 1, an external reservoir 5 configured to temporarily store the fluid and supply it to the rotating parts of the transmission 3, and a bidirectional pump 24 hydraulically connected to the oil sump 4 on the suction side via a fluid supply line 20. In this embodiment, the bidirectional pump 24 is hydraulically connected directly to the reservoir 5 on the first pressure side 22 and to the cooling nozzle 33 of the electromechanical machine 2 on the second pressure side 26. Therefore, a mode control valve for connecting the first pressure side 22 or the second pressure side 26 to the hydraulic transmission path 15 and the hydraulic stator path 14 respectively is not required. Pressure side cooling of the fluid can be provided for one or both of the hydraulic transmission path 15 and the hydraulic stator path 14 by arranging one or two heat exchangers.

[0037] However, in the illustrated embodiment, the electric drive device comprises an alternative cooling device 19 for cooling the fluid, which is arranged on the suction side of the bidirectional pump 24. Since the non-active first pressure side 22 or the second pressure side 26 of the bidirectional pump 24 each time becomes the suction side, the first pressure side 22 and the second pressure side 26 are connected at a suction side junction 27 upstream of the bidirectional pump 24 connected to the cooling device 19. A check valve 29 is arranged between the bidirectional pump 24 and the suction side junction 27 to prevent the backflow of the fluid from the active first pressure side 22 or the second pressure side 26 to the suction side each time. The cooling device 19 includes an inner casing portion 41 and an outer casing portion 42 of the housing 1, which form a casing cooling structure 43 through which an aqueous coolant flows. The housing shield 40 is arranged radially outside the outer casing portion 42 and at least partially below the rotational axis A of the rotor 10, thereby forming a shield cooling structure 44 through which the fluid can flow towards the oil sump 4 internally. The casing cooling structure 43 can also be arranged in the housing 1 of the aforementioned embodiment in the same way. The casing cooling structure 43 containing the coolant is hydraulically separated from the shield cooling structure 44 for the fluid, thereby providing heat exchange between the coolant and the fluid. Advantageously, a suction side heat exchanger for cooling the fluid is thus provided, as a result of which the pressure side heat exchanger and the mode control valve are omitted, and a less complex hydraulic circuit 7 is obtained.

[0038] The shield cooling structure 44 disposed below the rotational axis A of the rotor 10 collects the fluid for cooling the rotor 10 and the winding head 31. To further improve the heat exchange of the cooling device 19, the shield cooling structure 44 can include channels 45, 47 that extend substantially parallel to the axial direction. The channels 45, 47 advantageously provide a larger surface area and thus provide improved heat transfer from the fluid to the shield cooling structure 44. Further, the channels 45, 47 allow the use of both axial flow directions. Generally, the shield cooling structure 44 can have a downward slope to provide a flow of fluid by gravity, and the fluid flows, for example, into the oil sump 4 from the shield cooling structure 44 toward at least one outlet passage 46, which is indicated by the arrow F. Each of the channels 45, 47 may similarly have a downward slope. The shield cooling structure 44 can further include fins 48 connected to the outer cooling casing portion 42 and / or the housing shield 40. The fins 48 also provide a larger surface area and thus provide improved heat transfer from the fluid to the shield cooling structure 44. The flow of oil through the shield cooling structure 44 is indicated by the arrow F. The aqueous coolant within the casing cooling structure 43 can flow through a circumferential channel (not shown) formed within the inner casing portion 41 and thus forms a cross-flow heat exchanger. The shield cooling structure 44 can include a first channel 45 and a second channel 47 that extend substantially parallel to the axial direction. The first channel 45 can be separated from the second channel 47 by a wall 49, such that the oil can flow through the first channel 45 in an opposite axial direction compared to the flow of oil within the second channel 47. The shield cooling structure 44 further includes at least one inlet passage 50 for receiving fluid from the rotor 10 inside the inner casing portion 41, and the outlet passage 46 and the inlet passage 50 are axially arranged at opposite ends of the shield cooling structure 44. There can be two inlet passages 50 arranged at opposite ends of the shield cooling structure 44, and the fluid can flow through either the first channel 45 or the second channel 47.

[0039] The liquid level 36 in the oil sample 4 is indicated by two dashed lines. When the bidirectional pump 24 operates in the first rotational direction, the lower liquid level 36 appears, and when the bidirectional pump 24 operates in the second rotational direction, the higher liquid level 36 appears.

[0040] The illustrated portions and features of all exemplary embodiments of the electric drive device are schematic representations and may deviate from the technical drawing standards. Regarding the functions and technical details of the components and features, the description takes precedence over the drawings.

Description of Reference Numerals

[0041] 1 Housing 2 Electromechanics 3 Transmission 4 Oil sample 5 Reservoir 6 Transmission sample 7 Hydraulic circuit 8 Outlet 9 Stator 10 Rotor 11 Drive shaft 12 Mode control valve 14 Hydraulic stator path 15 Hydraulic transmission path 16 Intermediate wall 17 Conduit 18 Inner diameter portion of the rotor shaft 19 Cooling device 20 Fluid supply line 21 Radial bore 22 First pressure side 24 Bidirectional pump 25 Filter 26 Second pressure side 27 Suction side junction point 28 Pressure side junction point 29 Check valve device 30 Pressure line 31 Stator end winding 32 Spring 33 Cooling nozzle 34 Electric motor 35 Heat exchanger 36 Liquid level 37 Passage 38 Liquid level 39 Check valve spring 40 Housing shield 41 Inner casing part 42 Outer casing part 43 Casing cooling structure 44 Shield cooling structure 45 First channel 46 Outlet passage 47 Second channel 48 Fin 49 Wall 50 Inlet passage A Rotation axis F Arrow

Claims

1. An electric drive device for a vehicle, comprising: a housing (1); an electric machine (2) including a stator (9) connected to the housing (1) and including a stator end winding (31), and a rotor (10) rotatably supported within the housing (1) and having a drive shaft (11); a transmission (3) for transmitting the rotational movement from the drive shaft (11) to drive the driveline of the vehicle; a hydraulic circuit (7) for circulating a fluid to cool and lubricate the electric machine (2) and the transmission (3); characterized in that the hydraulic circuit (7) includes an oil sump (4) formed at a lower part of the housing (1); a reservoir (5) disposed above the oil sump (4) and configured to temporarily store oil and supply it to the rotating components of the transmission (3); a bi-directional pump (24) hydraulically connected to the oil sump (4) on the suction side, further hydraulically connected to the reservoir (5) on a first pressure side (22), and hydraulically connected to a cooling nozzle (33) of the electric machine (2) on a second pressure side (26); wherein when the bi-directional pump (24) operates in a first rotational direction, fluid is supplied to the reservoir (5), and when the bi-directional pump (24) operates in a second rotational direction, fluid is supplied to the cooling nozzle (33) to cool the stator end winding (31). An electric drive device.

2. The electric drive device according to claim 1, wherein the bi-directional pump (24) is further hydraulically connected to an inner diameter portion (18) of the drive shaft (11) and / or the transmission (3) via the reservoir (5), and when the bi-directional pump (24) operates in the first rotational direction, fluid is further supplied to the inner diameter portion (18) of the drive shaft (11) and / or the transmission (3).

3. The electric drive device according to claim 1 or 2, wherein the bi-directional pump (24) is hydraulically connected to a heat exchanger (35) on the first pressure side and / or the second pressure side.

4. The hydraulic circuit (7) includes a mode control valve (12) hydraulically connected to the bidirectional pump (24) on the first pressure side and the second pressure side, a hydraulic stator path (14) connecting the mode control valve (12) to the cooling nozzle (33), and a hydraulic transmission path (15) connecting the mode control valve (12) to the reservoir (5). The electric drive device according to any one of claims 1 to 3.

5. The electric drive device according to claim 4, wherein the mode control valve (12) is hydraulically actuated via a pressure line (30) hydraulically connected to the bidirectional pump (24) on the first pressure side (22).

6. When the bidirectional pump (24) is operated in the first rotational direction, the first pressure side is pressurized to a first pressure level for supplying fluid for active cooling of the rotor (10) and active lubrication of the transmission (3), and the liquid level in the transmission sump (6) is reduced by supplying fluid to the reservoir (5). The electric drive device according to any one of claims 1 to 5.

7. When the bidirectional pump (24) is operated in the second rotational direction, the second pressure side is pressurized to a second pressure level higher than the first pressure level to supply fluid to the cooling nozzle (33), while the liquid level in the transmission sump (6) rises. The electric drive device according to claim 6.

8. The electric drive device according to claim 2 or any one of claims 3 to 7 that cite claim 2, wherein the reservoir (5) is disposed inside the housing (1).

9. The electric drive device according to claim 8, wherein the reservoir (5) includes an inner diameter portion (18) of the drive shaft (11) and / or an outlet (8) for supplying fluid to the transmission (3).

10. The electric drive device according to claim 2 or any one of claims 3 to 7 that cite claim 2, wherein the reservoir (5) is disposed outside the housing (1).

11. The electric drive device according to claim 10, wherein the external reservoir (5) is hydraulically connected to the transmission (3) via a conduit (17) to supply fluid to the inner diameter portion (18) of the drive shaft (11) and / or the transmission (3).

12. The reservoir (5) is hydraulically connected to the oil sump (4), and when the bidirectional pump (24) is operated in the second rotational direction, fluid flows from the reservoir (5) back to the oil sump (4). The electric drive device according to any one of claims 1 to 11.

13. The suction side of the bidirectional pump (24) is connected to a cooling device (19) for cooling the fluid. The electric drive device according to any one of claims 1 to 12.

14. The cooling device (19) forms a casing cooling structure (43) through which an aqueous coolant flows inside, including an inner casing portion (41) and an outer casing portion (42) of the housing (1), and a housing shield (40) is disposed radially outside the outer casing portion (42) and at least partially below the rotational axis (A) of the rotor (10), thereby forming a shield cooling structure (44) through which fluid can flow towards the oil sump (4) inside. comprises The casing cooling structure (43) containing the coolant is hydraulically separated from the shield cooling structure (44) for the fluid, thereby providing heat exchange between the coolant and the fluid. The electric drive device according to claim 13.

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