Vehicle electric drive device

Abstract

The present invention relates to an electric drive for a vehicle, the electric drive including an electric machine (4) having a stator (7) connected to a housing (3) and including stator end windings (8, 8'), a rotor (9) rotatable relative to the stator (7), and a drive shaft (10) rotatably connected to the rotor (9), the electric drive including a transmission (5) for transmitting rotational motion from the drive shaft (10) to a driveline, the electric drive including a sump (6) containing a fluid for cooling and / or lubricating the electric machine (4) and the transmission (5), the electric drive including a hydraulic system (12) including at least one bidirectional pump (13, 14) and a pump (13, 14). a first suction line (24, 24') hydraulically connected to the pump (13, 14), a stator passage (17) for cooling the stator (7), a second suction line (25, 25') connected to the pump (13, 14), and a gear passage (18) for cooling the gear (5), the electric drive including a valve arrangement (16) with a plurality of valves (20, 21, 22, 23; 20', 21', 22', 23'), the plurality of valves (20, 21, 22, 23; 20', 21', 22', 23') configured such that fluid is supplied from the sump (6) through the first suction line (24, 24') to the stator passage (17) or through the second suction line (25, 25') to the gear passage (18).

Description

[Technical field]

[0001] The present invention relates to an electric drive assembly for a vehicle, comprising an electric machine, a transmission and a hydraulic device for cooling and / or lubricating the electric machine and the transmission.

[0002] From US 2019 / 0229582 A1, a vehicle drive unit is known that includes a lubrication path, which includes a first oil pump that pumps up oil stored in a case and supplies the pumped oil to a power transmission mechanism to lubricate the power transmission mechanism, and a cooling path that is separated from the lubrication path and is provided in the rotating electric machine. The cooling path includes a second oil pump that pumps up oil stored in a case and supplies the pumped oil exclusively to the rotating electric machine to cool the rotating electric machine. The second oil pump is an electric pump, and the cooling path is provided with an oil cooler that cools the oil supplied to the rotating electric machine.

[0003] US Patent Application Publication No. 2017 / 0285062 discloses an electric oil pump control method for operating a transmission of a hybrid vehicle driven by a first motor, a second motor, and an engine, which includes determining a rotation speed of a low-pressure pump of the electric oil pump based on a lubricating flow rate of the first motor, a lubricating flow rate of the second motor, a cooling flow rate of the first motor, and a cooling flow rate of the second motor, and determining a rotation speed of a high-pressure pump of the electric oil pump based on a control flow rate of a clutch of the transmission and a lubricating flow rate of a rotary drive device included in the transmission.

[0004] US 2019 / 0081537 A1 discloses a cooling system for a rotating electric machine for driving a vehicle. The cooling system includes a first pump that is driven in association with the running of the vehicle and supplies lubricating oil to the rotating electric machine, and a second pump that is driven by a second drive source and supplies lubricating oil to the rotating electric machine. The first pump is configured to supply lubricating oil to the inside of a rotating shaft of a rotor core of the rotating electric machine through a first oil passage. The second pump is configured to supply lubricating oil to a coil of a stator of the rotating electric machine through a second oil passage.

[0005] From WO 2020 / 069744, an electric drive for driving a motor vehicle is known, which comprises a housing assembly, an electric machine, a planetary gear transmission and an output branching unit. The housing assembly has a first housing part on the motor side, a second housing part on the transmission side and an intermediate housing part separating the motor space from the transmission space. The intermediate housing part has a motor-side housing part extending axially into the outer housing part of the first housing part and a transmission-side housing part extending axially into the second housing part. Between the outer surface of the motor-side housing part and the inner surface of the first housing part, a sealed cavity for the passage of a coolant is formed.

[0006] WO 2015 / 058788 discloses a drive assembly for a motor vehicle, comprising a first gear and a second gear drivingly connected to each other and a lubricant filling section defining a lubricant level in a static installation state of the drive assembly. A first reservoir is arranged above the lubricant level, which can be filled with lubricant as a result of the rotation of the first gear. A second reservoir is arranged above the lubricant level, which can be filled with lubricant as a result of the rotation of the second gear. The first reservoir is used to lubricate a first bearing area of ​​the drive assembly, while the second reservoir is used to lubricate a second bearing area of ​​the drive assembly.

[0007] The electric machine and the transmission of a vehicle electric drive have different cooling and lubrication requirements, which depend on the operating conditions. The performance of the electric machine is thermally limited during operation. Inherent losses can occur in the copper, iron, and magnets of the electric motor, and material properties limit the temperature of the respective components and structures. Effective cooling is necessary to achieve sufficient torque performance. Passive splash lubrication of the transmission can result in churning losses under high speed operation. Combining cooling and lubrication for both the electric machine and the transmission is a compromise on efficiency. Using one common controlled pump for the transmission and the electric motor allows on-demand lubrication and cooling, but is in any case a compromise between the needs of the electric motor and the needs of the transmission.

[0008] The object of the invention is therefore to propose an electric drive for a vehicle which comprises a hydraulic circuit for circulating a fluid for efficient cooling and lubrication of the electric machine and the transmission.

[0009] An electric drive for a vehicle, the electric drive including a housing, the electric drive including an electric machine, the electric machine including a stator connected to the housing and including stator end windings, a rotor rotatable relative to the stator, and a drive shaft rotatably connected to the rotor, the drive shaft being supported in a motor housing for rotation about an axis of rotation, the electric drive including a transmission for transferring rotational motion from the drive shaft to drive a driveline of the vehicle, the electric drive including a sump containing a fluid for cooling and / or lubricating at least one of the electric machine and the transmission, the electric drive including a hydraulic device, the hydraulic device including at least one An electric drive is provided, the electric drive including a bidirectional pump, a first suction line disposed between a sump and the pump, a stator path hydraulically connecting the pump and the electric machine to supply fluid for cooling the stator, a second suction line disposed between the sump and the pump, and a transmission path hydraulically connecting the pump and the transmission to supply fluid for cooling the transmission, the electric drive including a valve arrangement having a plurality of valves, the plurality of valves being configured such that, depending on a rotational direction of the bidirectional pump, fluid is supplied from the sump through the first suction line to the stator path for cooling the electric machine or fluid is supplied from the sump through the second suction line to the transmission path for cooling the transmission.

[0010] Thus, the electric drive provides an adaptive cooling and lubrication system that allows the appropriate amount of fluid to be supplied to the electric machine and the transmission to achieve good performance and efficiency with low complexity and power consumption. The operation of the electric machine dictates where and how much cooling is needed, which can be controlled accordingly by the hydraulic system. The electric drive described above can be operated in several different cooling regimes to achieve good cooling and / or lubrication depending on the need.

[0011] Insofar as it is stated in the present disclosure that an electric machine or a transmission is cooled, it is understood that this relates to primarily / actively cooling the aforementioned components, and that other components not mentioned may be indirectly / passively cooled. Furthermore, insofar as the present disclosure generally refers to a fluid, it is understood that this fluid may be any fluid suitable for cooling and / or lubricating the aforementioned components, in particular parts of the electric machine and / or parts of the transmission. For example, oil may be used as a coolant / lubricant for an electric drive.

[0012] The electric drive may include a bidirectional single or dual pump device combined with a single or dual sump and cooling system. Bidirectional operation allows for two different lubrication or cooling regimes, specifically configured for low speed / high torque and high speed / low torque operation of the electric machine. The bidirectional pump may be electrically driven, and load-dependent fluid flow may be achieved, for example, by controlling the speed of the respective pump. In a low speed / high torque mode of the electric machine, the pump may be driven in a first direction of rotation. In this mode, the pump delivers fluid from the sump primarily to the stator and winding head of the electric machine. In a high speed / low torque operation of the electric machine, the pump may be driven in the opposite direction of rotation. In this mode, the pump delivers fluid from the sump primarily to the stator and rotor of the electric machine for cooling the magnets and laminations. By combining a first low pressure / high flow bidirectional pump with a second high pressure / low flow bidirectional pump, the lubrication cooling system can be split into a low pressure / high flow circuit (e.g. for stator cooling, rotor cooling, transmission lubrication) and a high pressure / low flow circuit (e.g. for end winding spray cooling at high speed operation, gear spray lubrication), allowing even more sophisticated and effective cooling / lubrication concepts.

[0013] In the following, some further specifications of the invention are described in more detail, with the understanding that in this context any description of one component may also be applied to the further respective components, for example any technical feature described in relation to one pump, sump, valve or other component may also be applied to any other pump, sump, valve or component, respectively.

[0014] The valve arrangement is configured to control the flow of fluid depending on the direction of rotation of the respective pump. The valve arrangement may include a check valve disposed in the first suction line, a check valve disposed in the second suction line, a check valve disposed in a first pressure line that is part of the transmission path, and / or a check valve disposed in a second pressure line that is part of the stator path. The first suction line may be connected to a first inlet of the pump, and the second suction line may be connected to a second inlet of the pump. A fluid supply line may be provided to hydraulically connect the sump to the first suction line and the second suction line. For example, a suction filter may be disposed upstream of the pump in the fluid supply line. For example, a heat exchanger may be disposed downstream of the pump in the stator path.

[0015] According to one embodiment, the hydraulic device may include a first bidirectional pump and a second bidirectional pump, which may be functionally arranged in parallel with each other between a sump on the suction side and an electric machine or a transmission on the pressure side. In such a device with two bidirectional pumps, it may be possible to control the hydraulic device such that in a low speed mode, both the first bidirectional pump and the second bidirectional pump are driven to supply fluid from the sump to the stator path for cooling the electric machine. In a medium speed mode, one of the two bidirectional pumps may be driven to supply fluid from the sump to the stator path, while the other of the two pumps is driven to supply fluid from the sump to the transmission path. In a high speed mode, both bidirectional pumps may be driven to supply fluid from the sump to the transmission path.

[0016] As mentioned above, the sump can include one single sump with a single connection to the pump for both the electric machine and the transmission, or alternatively, two separate sumps with separate connections to the pumps, a motor-side reservoir associated with the electric machine and a transmission-side reservoir associated with the transmission. Fluid splash or drip from any rotating components of the electric drive during operation can be temporarily stored in the sump. From there, the fluid can be recirculated by the rotating components or by at least one pump that delivers fluid from the sump to locations to be cooled and / or lubricated on demand.

[0017] In the embodiment with two bi-directional pumps and one single sump capable of storing the fluids of the electric machine and the transmission (FIGS. 1A-1D, 2), the first and second suction lines of both bi-directional pumps are hydraulically connected to the common sump, which therefore has only one sump line connected to it.

[0018] In the embodiment with two bidirectional pumps and a sump with two reservoirs, a motor-side reservoir and a gear-side reservoir (FIGS. 3A-3C), the first suction lines of both bidirectional pumps are hydraulically connectable to the motor-side reservoir and the second suction lines of both bidirectional pumps are hydraulically connectable to the gear. More specifically, the motor sump line is hydraulically connectable to the first suction line / suction side inlet of the first bidirectional pump and to the first suction line / suction side inlet of the second bidirectional pump. Correspondingly, the gear sump line is hydraulically connectable to the second suction line / second suction side inlet of the first bidirectional pump and to the second suction line / second suction side inlet of the second bidirectional pump.

[0019] In the low speed / high torque mode (FIG. 3B), both pumps may be driven to supply fluid from the motor reservoir mainly to the stator and / or winding head of the electric machine. The removal of liquid from the motor reservoir can result in an increase in the fluid level in the gearing reservoir, which allows for more immersion of the gearing. In this mode, the gearing is operating with passive lubrication. In the medium speed / medium torque mode (FIG. 3C), the two pumps can operate functionally inversely to each other, i.e., one pump draws fluid from the gearing reservoir and supplies this fluid mainly to the gearing to cool it, and the other pump draws fluid from the motor reservoir and supplies this fluid mainly to the stator and / or rotor of the electric machine to cool the electric machine. The removal of fluid from the gearing reservoir can result in a decrease in the fluid level in this reservoir, which allows for less immersion of the gears. In this mode, the gearing is actively lubricated to reduce churning losses and obtain high efficiency. In high speed / low torque mode (FIG. 3D), both pumps may be driven to supply fluid to one or more parts of the gearing primarily from the gearing reservoir. By drawing fluid for both pumps from the gearing reservoir, a reduced fluid level in the gearing reservoir can be achieved, resulting in only slight immersion of the gearing and therefore only slight gearing losses.

[0020] In an embodiment with only one single bidirectional pump and two reservoirs, a motor-side reservoir and a gear-side reservoir (FIGS. 4A-4D), a first suction line of the bidirectional pump can be hydraulically connected to the motor-side reservoir and a second suction line of the bidirectional pump can be hydraulically connected to the gear-side reservoir. In this case, the hydraulic device can be controlled such that in a low-speed mode (FIG. 4B) the bidirectional pump is driven to supply fluid from the motor-side reservoir to the stator path for cooling the electric machine, and in a high-speed mode (FIG. 4C) the hydraulic device can be controlled such that the bidirectional pump is driven to supply fluid from the gear-side reservoir to the gear path for cooling the gear.

[0021] In an embodiment applicable to any of the above embodiments, the hydraulic transmission path may include a branched conduit to the inner longitudinal bore of the drive shaft. Since active lubrication of the transmission does not require a high pressure fluid supply, in high speed mode, low pressure cooling fluid may be supplied to the electric machine via the drive shaft. In high speed mode, fluid may be supplied to the electric machine via radial bores of the drive shaft connecting the longitudinal bore of the drive shaft to the rotor and / or stator. This may cool the rotor and may further centrifuge the fluid towards the stator and stator end windings, which may also cool the stator end windings. Additionally, the hydraulic stator path may include a branched jacket line to an electric machine jacket cooling structure located within the electric machine housing. This may allow the electric machine jacket to be cooled by the same fluid used to cool the inner parts of the electric drive, i.e., no separate water cooling is required.

[0022] In any of the above embodiments, the housing of the electric drive may include an intermediate wall separating the interior space into a motor-side chamber and a transmission-side chamber. The intermediate wall may have through openings disposed therein through which fluid may flow from the transmission-side reservoir to the motor-side reservoir. As described above, in the low speed mode, fluid may be passively supplied from the sump to the transmission, and in the low speed mode, the fluid level in the transmission-side reservoir may be higher than the fluid level in the high speed mode.

[0023] Exemplary embodiments and further advantages of an electric drive for a motor vehicle are explained below with reference to the accompanying drawings. [Brief description of the drawings]

[0024] [Figure 1A] 1 is a schematic diagram showing a first exemplary embodiment of an electric drive according to the invention; [Figure 1B] FIG. 1B illustrates the embodiment of FIG. 1A in a low speed mode. [Figure 1C] FIG. 1B illustrates the embodiment of FIG. 1A in a medium speed mode. [Figure 1D] FIG. 1B illustrates the embodiment of FIG. 1A in high speed mode. [Diagram 2] FIG. 2 shows a schematic diagram of an electric drive according to the invention in a modified embodiment. [Figure 3A] 2 is a schematic diagram showing another exemplary embodiment of an electric drive according to the invention; [Figure 3B] FIG. 3B illustrates the embodiment of FIG. 3A in a low speed mode. [Figure 3C] FIG. 3B illustrates the embodiment of FIG. 3A in a medium speed mode. [Figure 3D] FIG. 3B illustrates the embodiment of FIG. 3A in high speed mode. [Figure 4A] 2 is a schematic diagram showing another exemplary embodiment of an electric drive according to the invention; [Figure 4B] FIG. 4B illustrates the embodiment of FIG. 4A in a low speed mode. [Figure 4C] FIG. 4B illustrates the embodiment of FIG. 4A in high speed mode. [Diagram 5] FIG. 2 illustrates various modes of operation in tabular form.

[0025] 1A-1D, also collectively referred to as FIG. 1, show an electric drive 2 according to the invention in a first embodiment. The electric drive 2 includes a housing 3, an electric machine 4, a transmission 5, and a sump 6, which are shown as a schematic longitudinal section along a rotation axis A4 of the electric machine 4. The electric machine 4 has a stator 7 connected to the housing 3 and including stator end windings 8, and a rotor 9 rotatable relative to the stator 7. A drive shaft 10 is connected to the rotor 9 and is supported in the housing 3 for rotation about the rotation axis A4 via bearings 19, 19′. The transmission 5 is adapted to transmit a rotary motion from the drive shaft 10 for driving a driveline of a vehicle, not shown. The transmission 5 may include, for example, at least one of a reduction gear mechanism, a differential gear mechanism, and a coupling, not shown.

[0026] A hydraulic system 12 is shown diagrammatically, comprising a first bidirectional pump 13 and a second bidirectional pump 14 hydraulically connected to the sump 6 via a fluid supply line 15, a valve arrangement 16 with a number of valves, a hydraulic stator path 17 connecting each of the two pumps 13, 14 to a part of the electric machine 4 for supplying fluid to the stator 7, and a hydraulic transmission path 18 connecting each of the two pumps 13, 14 to a part of the transmission 3 for cooling the transmission 3. The hydraulic system 12 may therefore also be referred to as a hydraulic circuit or a cooling system.

[0027] The valves 20, 21, 22, 23; 20', 21', 22', 23' are constructed and / or arranged to provide fluid from the sump 6 through a first suction line 24, 24' to the stator path 17 for cooling the electric machine 4 or through a second suction line 25, 25' to the gearing path 18 for cooling a portion of the gearing 5, depending on the direction of rotation of the respective bidirectional pump 13, 14. At least some of the valves 20, 21, 22, 23; 20', 21', 22', 23' may be configured as, but are not limited to be, check valves.

[0028] In the following, the hydraulic device is described with respect to the first pump 13. The first valve 20 is arranged in the first suction line 24, the second valve 21 in the second suction line 25, the third valve 22 in the first pressure line 26 which is part of the transmission path 18, and the fourth valve 23 in the second pressure line 27 which is part of the stator path 17. The first suction line 24 is connected to the first inlet of the pump 13, and the second suction line 25 is connected to the second inlet of the pump 13. The hydraulic device of the second pump 14 is arranged functionally parallel to the hydraulic device of the first pump 13 and is constructed similarly to the hydraulic device of the first pump 13, and reference is made in brief to its description in this document, with the respective reference numbers of the lines and valves being given subscripts. In the fluid supply line 15, a suction filter 11 is arranged. A heat exchanger 19 is arranged in the stator path 17 downstream of the pumps 13, 14.

[0029] The stator path 17 is divided into a first branch 28 for supplying fluid to a first stator cooling unit 29 and a second branch 28' for supplying fluid to an opposite second stator cooling unit 29'. The cooling units 29, 29' may each include a ring channel and a number of circumferentially distributed cooling nozzles directed towards the respective first and second stator end windings 8, 8'. When the hydraulic device is operated to supply fluid to the stator path 17, active cooling of the stator 7, in particular of the stator end windings 8, 8', is achieved with a high cooling effect.

[0030] The hydraulic transmission path 18 includes a branch 30 to the inner part of the transmission 5, which can include a transmission reservoir 31, for example arranged at a higher level than the sump 6. The fluid supplied to the transmission reservoir 31 can thus flow or drip by gravity onto the rotating parts of the transmission, such as gears and bearings, to cool and / or lubricate them. The fluid can then be collected in the sump 6 and recirculated by a pump. The transmission path 18 further includes a branch 32 to an inner longitudinal bore 33 of the drive shaft 10. Thus, when the electric drive 2 is operated in high-speed mode and fluid is mainly supplied to the transmission 5, a low-pressure cooling fluid is supplied to the electric machine 4 via the drive shaft 10. For this purpose, the drive shaft 10 is configured as a hollow shaft with radial bores 34, 34' connected to the longitudinal bore 33. This allows for part of the rotor 9 to be cooled and for the fluid to be centrifuged radially outwards towards the stator 7, in particular towards the stator end windings 8, 8'. Thus, when the hydraulic system is operated to supply fluid to the transmission 5, the electric machine 4 is passively cooled at the same time.

[0031] In the embodiment shown in Figure 1 including two bidirectional pumps 13, 14, the hydraulic device 12 can be controlled in a number of different operating modes. In a low speed / high torque mode, both the first bidirectional pump 13 and the second bidirectional pump 14 may be driven to supply fluid from the sump 6 through the fluid supply line 15, the suction lines 24, 24' and the pressure lines 27, 27' through the stator path 17 to cool the electric machine 4. The low speed / high torque mode fluid supply is shown in solid lines in Figure 1B. Both pumps 13, 14 are driven in the same rotational direction, e.g., clockwise.

[0032] In medium speed / medium torque mode, the bi-directional pump 14 is driven to supply fluid from the sump 6 to the stator path 17 while the other pump 13 is driven to supply fluid from the sump 6 to the transmission path 18. The fluid flow in medium speed / medium torque mode is shown in solid lines in Figure 1C. The pumps 13, 14 are driven in opposite rotational directions, one clockwise and the other counterclockwise.

[0033] In high speed / low torque mode, both bi-directional pumps 13, 14 are driven to supply fluid from the sump 6 to the transmission path 18. The fluid flow in high speed / low torque mode is shown in solid lines in Figure ID. Both pumps 13, 14 are driven in the same rotational direction, e.g., counterclockwise.

[0034] In the embodiment shown in FIG. 1 , the electric drive 2 includes one common sump 6 in which the fluid of the electric machine 4 and the fluid of the transmission 5 are collected, i.e. the first suction lines 24, 24' and the second suction lines 25, 25' of both bidirectional pumps 13, 14 respectively are hydraulically connected to the common sump 6 via one single fluid supply line 15 connected to the single sump 6.

[0035] Optionally, the housing 3 of the electric drive 2 includes an intermediate wall 35 separating the housing interior space into a motor-side chamber and a transmission-side chamber, the intermediate wall 35 being provided with a through-opening 36 through which fluid can flow from the transmission-side reservoir to the motor-side reservoir and vice versa depending on the respective fluid levels.

[0036] Furthermore, the housing 3 may optionally include a jacket cooling 37 for the electric machine 4. The jacket cooling 37 may include a cooling structure extending circumferentially around the stator 7 for cooling the stator 7. The cooling structure may for example have one or more meander-shaped channels through which a cooling fluid, in particular a water-based coolant, may flow in order to absorb heat generated by the stator.

[0037] Figure 2 shows the electric drive 2 according to the invention in a modified embodiment. This embodiment corresponds broadly to the embodiment shown in Figure 1, therefore reference is made to the above description for the common features. The only difference in the embodiment shown in Figure 2 is that for the jacket cooling structure 37 the same fluid is used as that used for the inner part of the electric drive 2. For this purpose, the hydraulic stator path 17 includes a branched jacket line 38 connected to the jacket cooling structure 37 of the electric machine 4 arranged in the housing 3 of the electric machine 4.

[0038] Figures 3A to 3D, also collectively referred to as Figure 3, show an electric drive 2 according to the invention in another embodiment. This embodiment corresponds broadly to the embodiment shown in Figure 1, therefore reference is made to the above description for common features. In this respect, the same details are provided with the same reference numerals as those in Figure 1.

[0039] This embodiment comprises two bi-directional pumps 13,14 and a sump 6 with two separate reservoirs, namely a motor-side reservoir 39 and a gear-side reservoir 40. In this case, the first suction lines 24,24' of both bi-directional pumps 13,14 are hydraulically connected to the motor-side reservoir 39 and correspondingly the second suction lines 25,25' of both pumps 13,14 are hydraulically connected to the gear-side reservoir 40. A motor sump line 15 is hydraulically connected to the first suction line 24 connected to a first suction-side inlet of the first bi-directional pump 13 and to a first suction line 24' connected to a respective first inlet of the second pump 14. Correspondingly, the transmission sump line 41 is hydraulically connected to a second suction line 25 connected to a second inlet of the first pump 13 and to a second suction line 25' connected to a second inlet of the second pump 14.

[0040] In low speed / high torque mode, where the respective fluid flows are shown in solid lines in Figure 3B, both pumps 13, 14 may be driven to supply fluid from the motor side reservoir 39 through the motor sump line 15 to the cooling units 29, 29' primarily for cooling the stator 7 and / or winding heads 8, 8' of the electric machine 4. Removal of liquid from the motor reservoir 39 can result in an increase in the fluid level in the transmission reservoir 40, which allows for greater immersion of the transmission 5. In this mode, the transmission 5 is operating with passive lubrication.

[0041] In the medium speed / medium torque mode, the respective fluid flows of which are shown in solid lines in FIG. 3C, the two pumps can operate functionally inversely to each other, i.e. pump 13 draws fluid from the gearing reservoir 40 through line 41 to cool the gearing 5 and supplies this fluid mainly to the gearing 5, and pump 14 draws fluid from the motor reservoir 39 through line 15 to cool the stator 7 and / or rotor 9 of the electric machine 4 and supplies this fluid to the cooling units 29, 29′. In this case, the withdrawal of fluid from the gearing reservoir 40 results in a lowering of the fluid level, which reduces the immersion of the gears. In this mode, the gearing 5 is actively lubricated to reduce churning losses and obtain high efficiency.

[0042] In a high speed / low torque mode, with the respective fluid flows shown in solid lines in Figure 3D, both pumps 13, 14 may be activated to supply fluid from the transmission reservoir 40 through lines 41, 24, 25', 26, 26', 18, 30, 32 to one or more portions of the transmission 5. By drawing fluid from the transmission reservoir 40 for both pumps 13, 14, a lowering of the fluid level in the transmission reservoir 40 may be achieved, which results in only minor flooding of the transmission 5 and therefore only minor losses in the transmission 5.

[0043] Figures 4A to 4C, also collectively referred to as Figure 4, show an electric drive 2 according to the invention in another embodiment. This embodiment corresponds broadly to the embodiment shown in Figure 3, therefore reference is made to the above description for common features. In this regard, the same details are provided with the same reference numerals as those of Figures 3, 2 and 1, respectively.

[0044] 4 is characterized in that only one bidirectional pump 13 is provided and that the sump 6 includes two separate reservoirs, a motor-side reservoir 39 and a gear-side reservoir 40. A first suction line 24 of the bidirectional pump 13 is hydraulically connected to the motor-side reservoir 39 and a second suction line 25 of the pump 13 is hydraulically connected to the gear-side reservoir 40.

[0045] In this embodiment, the hydraulic device 12 can be controlled such that in a low speed mode, the bidirectional pump 13 is driven to supply fluid from the motor-side reservoir 39 to the stator path 17 primarily for cooling the electric machine 4. The flow paths for this mode are shown in solid lines in FIG. 4B. In a high speed / low torque mode, the bidirectional pump 13 is driven to supply fluid from the transmission-side reservoir 40 to the transmission path 18 primarily for cooling the transmission 5. The flow paths for this high speed mode are shown in solid lines in FIG. 4C.

[0046] In Fig. 5, exemplary operating modes for an electric drive 2 with two bidirectional pumps 13, 14 as shown in any of Figs. 1 to 3 are shown diagrammatically, where P1 refers to the first pump, P2 refers to the second pump, CS refers to the cooling system, MD refers to the mode and OP refers to the operation of the electric drive 2.

[0047] In low power operation (Olp) of the electric drive 2, the first pump (P1) and the second pump (P2) can be switched off (0) and the cooling system therefore operates with only passive lubrication (C0), i.e. without active oil cooling. The system operates in energy saving mode (Ms).

[0048] In high torque and low speed operation (Ot) of the electric drive 2, both the first pump P1 and the second pump P2 are switched on and driven in the same direction of rotation (rd1), e.g. clockwise, and thus the cooling system generates a maximum fluid supply to the electric motor 4, in particular to the cooling units 29, 29', mainly for cooling the stator end windings 8, 8' (Cm). This mode is characterized by a maximum torque, indicated as Mt. The gearing of the electric drive is passively lubricated and / or cooled, i.e. there is no active rotor cooling, and the fluid level in the gearing is high.

[0049] In medium torque and medium speed operation (Omed) of the electric drive 2, both the first pump (P1) and the second pump (P2) are switched on to be driven in opposite rotational directions (rd1, rd2) and thus the cooling system generates a medium fluid supply to the electric motor 4 and the gearing 5 (Cmed). This mode can be referred to as a transition mode, denoted as Mmed. Thus, low-flow spray cooling is combined with limited rotor cooling and active gearing lubrication, making it possible to reduce the gearing oil level.

[0050] At high speed operation (Ov) of the electric drive 2, both the first pump P1 and the second pump P2 are switched on to be driven in the same direction of rotation (rd2), for example counterclockwise, and thus the cooling system generates a maximum fluid supply to the gearing 5 and the rotor 9 (Ct). This mode can be referred to as high speed mode, indicated as Mv. Thus, active gearing lubrication via centrifuged oil from the rotor and cooling of the winding heads is provided, and it is possible to reduce the gearing oil level.

[0051] The operation of the hydraulic device can be controlled depending on the operating mode of the electric machine. At low speeds and high torque, it is important to cool the stator and end windings because copper losses are large. At low torque and high speed, eddy current losses in the laminations and magnets increase significantly. In these conditions, cooling the magnets and the rotor and stator laminations requires special attention. The lubrication of the transmission should also be tailored to the operating conditions. At high torque and low speed, passive lubrication will be sufficient. At high speed and low torque, active lubrication can be used to reduce and concentrate the oil flow to minimize churning losses. [Explanation of symbols]

[0052] 2 Electric drive unit 3. Housing 4. Electrical Machinery 5 Transmission 6. Samp 7 Stator 8,8' Stator end windings 9 Rotor 10 Drive shaft 11,11' Suction filter 12 Hydraulic Devices 13. Two-way pump 14 Two-way pump 15 Fluid Supply Line 16 Valve gear 17 Stator path 18 Transmission Path 19 Heat exchanger 20,20' valve 21,21' Valve 22,22' Valve 23,23' Valve 24,24' suction line 25,25' suction line 26,26' Pressure Line 27,27' Pressure Line 28,28' Branch 29,29' Cooling unit 30 Branch 31 Transmission Reservoir 32 Branches 33 Longitudinal hole 34,34' radial hole 35 Intermediate Wall 36 Through opening 37 Jacket cooling structure 38 Jacket Line 39 Samp 40 Sump A axis

Claims

1. An electric drive device for a vehicle, The electric drive includes a housing (3), The electric drive includes an electric machine (4), the electric machine (4) a stator (7) connected to the housing (3) and including stator end windings (8, 8'); a rotor (9) rotatable relative to the stator (7); a drive shaft (10) non-rotatably connected to the rotor (9); Equipped with The drive shaft (10) is supported by the housing (3) so as to be rotatable about a rotation axis (A4), the electric drive includes a transmission (5) for transmitting rotational motion from the drive shaft (10) to a driveline of the vehicle; the electric drive includes a sump (6) with a fluid for cooling and / or lubricating at least one of the electric machine (4) and the transmission (5); The electric drive unit includes a hydraulic unit (12), the hydraulic unit (12) comprising: at least one bidirectional pump (13, 14); a first suction line (24, 24') arranged between the sump (6) and the pump (13, 14); a stator path (17) arranged between the pump (13, 14) and the electric machine for supplying a fluid for cooling the stator (7); a second suction line (25, 25') arranged between the sump (6) and the pump (13, 14); a transmission line (18) arranged between the pump (13, 14) and the transmission (5) for supplying a fluid for cooling the transmission (5); Including, the electric drive includes a valve device (16) with a plurality of valves (20, 21, 22, 23; 20', 21', 22', 23'), the plurality of valves (20, 21, 22, 23; 20', 21', 22', 23') are configured to supply fluid from the sump (6) through the first suction line (24, 24') to the stator path (17) for cooling the electric machine (4) or to supply fluid from the sump (6) through the second suction line (25, 25') to the transmission path (18) for cooling the transmission (5), depending on the direction of rotation of the bidirectional pump (13, 14); The hydraulic device (12) includes a first bidirectional pump (13) and a second bidirectional pump (14); the first bidirectional pump (13) and the second bidirectional pump (14) are hydraulically arranged in parallel between the sump (6) on the suction side and the electric machine (4) or the transmission on the pressure side; the sump (6) is configured as a common sump containing the fluid of the electric machine (4) and the fluid of the transmission (5), and only one sump line (15) is hydraulically connected to the common sump; the first suction line (24, 24') and the second suction line (25, 25') of both the first bidirectional pump (13) and the second bidirectional pump (14) are hydraulically connected to the common sump via the sump line (15); Electric drive unit.

2. The valve device (16) a first check valve (20, 20') disposed in the first suction line (24, 24'); a second check valve (21, 21') arranged in the second suction line (25, 25'); a third check valve (22, 22') disposed in a first pressure line (26, 26') that is part of the transmission path (18); a fourth check valve (23, 23') disposed in a second pressure line (27, 27') that is part of the stator path (17); Including, 2. The electric drive system according to claim 1.

3. and in a low speed mode, the hydraulic device (12) can be controlled such that both the first bidirectional pump (13) and the second bidirectional pump (14) are driven to supply fluid from the sump (6) to the stator path (17) for cooling the electric machine (4); the hydraulic device (12) can be controlled such that, in a medium speed mode, one of the first and second bidirectional pumps (13, 14) is driven to supply fluid from the sump (6) to the stator path (17) for cooling the electric machine (4), and the other of the first and second bidirectional pumps (14, 13) is driven to supply fluid from the sump (6) to the transmission path (18) for cooling the transmission (5); and In a high speed mode, the hydraulic device (12) can be controlled such that both the first bidirectional pump (13) and the second bidirectional pump (14) are driven to supply fluid from the sump (6) to the transmission path (18) for cooling the transmission (5).

2. The electric drive system according to claim 1.

4. An electric drive device for a vehicle, The electric drive includes a housing (3), The electric drive includes an electric machine (4), the electric machine (4) a stator (7) connected to the housing (3) and including stator end windings (8, 8'); a rotor (9) rotatable relative to the stator (7); a drive shaft (10) non-rotatably connected to the rotor (9); Equipped with The drive shaft (10) is supported by the housing (3) so as to be rotatable about a rotation axis (A4), the electric drive includes a transmission (5) for transmitting rotational motion from the drive shaft (10) to a driveline of the vehicle; the electric drive includes a sump (6) with a fluid for cooling and / or lubricating at least one of the electric machine (4) and the transmission (5); The electric drive unit includes a hydraulic unit (12), the hydraulic unit (12) comprising: at least one bidirectional pump (13, 14); a first suction line (24, 24') arranged between the sump (6) and the pump (13, 14); a stator path (17) arranged between the pump (13, 14) and the electric machine for supplying a fluid for cooling the stator (7); a second suction line (25, 25') arranged between the sump (6) and the pump (13, 14); a transmission line (18) arranged between the pump (13, 14) and the transmission (5) for supplying a fluid for cooling the transmission (5); Including, the electric drive includes a valve device (16) with a plurality of valves (20, 21, 22, 23; 20', 21', 22', 23'), the plurality of valves (20, 21, 22, 23; 20', 21', 22', 23') are configured to supply fluid from the sump (6) through the first suction line (24, 24') to the stator path (17) for cooling the electric machine (4) or to supply fluid from the sump (6) through the second suction line (25, 25') to the transmission path (18) for cooling the transmission (5), depending on the direction of rotation of the bidirectional pump (13, 14); The hydraulic device (12) includes a first bidirectional pump (13) and a second bidirectional pump (14); the first bidirectional pump (13) and the second bidirectional pump (14) are hydraulically arranged in parallel between the sump (6) on the suction side and the electric machine (4) or the transmission on the pressure side; The sump (6) includes a motor-side reservoir (39) associated with the electric machine (4) and a transmission-side reservoir (40) associated with the transmission (5); the first suction lines (24, 24') of both the first bidirectional pump (13) and the second bidirectional pump (14) are hydraulically connected to the motor-side reservoir (39); the second suction lines (25, 25') of both the first bidirectional pump (13) and the second bidirectional pump (14) are hydraulically connected to the transmission-side reservoir (40); Electric drive unit.

5. a motor sump line (15) hydraulically connected to the first suction line (24) of the first bidirectional pump (13) and to the first suction line (24') of the second bidirectional pump (14); a transmission sump line (41) hydraulically connected to the second suction line (25) of the first bidirectional pump (13) and to the second suction line (25') of the second bidirectional pump (14); and in a low-speed mode, the hydraulic device (12) can be controlled such that both the first bidirectional pump (13) and the second bidirectional pump (14) are driven to supply fluid from the motor-side reservoir (39) to the stator path (17) for cooling the electric machine (4); In a medium speed mode, the hydraulic device (12) can be controlled so that the first bidirectional pump (13) is driven to supply fluid from the transmission-side reservoir (40) to the transmission path (18) to cool the transmission (5), and the second bidirectional pump (14) is driven to supply fluid from the motor-side reservoir (39) to the stator path (17) to cool the electric machine (4); In a high speed mode, the hydraulic device (12) can be controlled so that both the first bidirectional pump (13) and the second bidirectional pump (14) are driven to supply fluid from the transmission-side reservoir (40) to the transmission path (18) for cooling the transmission (5).

5. The electric drive system according to claim 4.

6. An electric drive device for a vehicle, The electric drive includes a housing (3), The electric drive includes an electric machine (4), the electric machine (4) a stator (7) connected to the housing (3) and including stator end windings (8, 8'); a rotor (9) rotatable relative to the stator (7); a drive shaft (10) non-rotatably connected to the rotor (9); Equipped with The drive shaft (10) is supported by the housing (3) so as to be rotatable about a rotation axis (A4), the electric drive includes a transmission (5) for transmitting rotational motion from the drive shaft (10) to a driveline of the vehicle; the electric drive includes a sump (6) with a fluid for cooling and / or lubricating at least one of the electric machine (4) and the transmission (5); The electric drive unit includes a hydraulic unit (12), the hydraulic unit (12) comprising: at least one bidirectional pump (13, 14); a first suction line (24, 24') arranged between the sump (6) and the pump (13, 14); a stator path (17) arranged between the pump (13, 14) and the electric machine for supplying a fluid for cooling the stator (7); a second suction line (25, 25') arranged between the sump (6) and the pump (13, 14); a transmission line (18) arranged between the pump (13, 14) and the transmission (5) for supplying a fluid for cooling the transmission (5); Including, the electric drive includes a valve device (16) with a plurality of valves (20, 21, 22, 23; 20', 21', 22', 23'), the plurality of valves (20, 21, 22, 23; 20', 21', 22', 23') are configured to supply fluid from the sump (6) through the first suction line (24, 24') to the stator path (17) for cooling the electric machine (4) or to supply fluid from the sump (6) through the second suction line (25, 25') to the transmission path (18) for cooling the transmission (5), depending on the direction of rotation of the bidirectional pump (13, 14); The hydraulic device (12) includes only one bidirectional pump (13), The sump (6) includes a motor-side reservoir (39) associated with the electric machine (4) and a transmission-side reservoir (40) associated with the transmission (5); the first suction line (24) of the bidirectional pump (13) is hydraulically connected to the motor-side reservoir (39), and the second suction line (25) of the bidirectional pump (13) is hydraulically connected to the transmission-side reservoir (40); In a low speed mode, the hydraulic device (12) can be controlled such that the bidirectional pump (13) is driven to supply fluid from the motor-side reservoir (39) to the stator path (17) for cooling the electric machine (4); In a high-speed mode, the hydraulic device (12) can be controlled so that the bidirectional pump (13) is driven to supply fluid from the transmission-side reservoir (40) to the transmission path (18) for cooling the transmission (5). Electric drive unit.

7. In the low speed mode, the transmission (5) is passively supplied with fluid from the sump (6); In the low speed mode, the flow surface in the transmission-side reservoir (40) can be higher than the flow surface in the high speed mode.

7. An electric drive system according to claim 5 or 6.

8. The transmission path (18) includes a shaft line (32) branching into an inner longitudinal bore (33) of the drive shaft (10); In the high speed mode, the electric machine (4) is supplied with fluid through radial holes (34, 34') in the drive shaft (10) connecting the inner longitudinal hole (33) to the rotor (9) or the stator of the electric machine (4).

7. An electric drive system according to claim 5 or 6.

9. The housing (3) includes an intermediate wall (35) that separates the interior space into a motor-side chamber and a transmission-side chamber; The intermediate wall (35) has a through opening (36) arranged therein, through which a fluid can flow.

9. An electric drive system according to any one of claims 1 to 8.

10. A heat exchanger (19) is disposed in the stator path (17), The stator path (17) includes a jacket line (38) branching off to a jacket cooling structure (37) of the electric machine (4) disposed within the housing (3).

10. An electric drive system according to any one of claims 1 to 9.

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