Electric axle drive

Abstract

The invention relates to an electric axle drive (10) for driving a motor vehicle. The electric axle drive (10) comprises a first pump (27), a second pump (47), a first interior (19), a second interior (20), a hydraulic pressure line (33), an electric motor (12) and a gearbox (13), wherein - the first pump (27) is designed to draw oil from the first interior (19) and deliver it to the pressure oil line (33) to cool and / or lubricate the electric motor (12) and the gearbox (13), - Oil from the pressure oil line (33) forms a primary oil sump (40) in the first interior space (19) and a secondary oil sump (43) in the second interior space (20) and - the second pump (47) is designed to draw oil from the secondary oil sump (43) and supply it to the primary oil sump (40).

Description

[0001] The invention relates to an electric axle drive for driving a motor vehicle.

[0002] Extensive requirements for future electric vehicle powertrains encompass various objectives. Firstly, there is a trend in the automotive sector to create more installation space for the passenger compartment and cargo area. This results in increasingly smaller installation spaces for drive units. Simultaneously, there is a customer demand for increased power output from the drive unit, reflected, among other things, in the overall vehicle's longitudinal and lateral acceleration values. This leads to a higher power density in the drive unit. The key to successfully meeting this challenge lies primarily in optimal lubrication and cooling of the drive unit. Modern electric axle drives rely on oil-lubricated and cooled concepts. The better this oil flow can be maintained in the electric axle drive – even during dynamic driving maneuvers – the more efficient the overall vehicle becomes.

[0003] One object of the invention is to provide improved oil lubrication and oil cooling that solves the problems described above in a compact and cost-effective manner. This object is achieved by the subject matter of the independent claims. Advantageous embodiments are the subject of the dependent claims, the following description, and the figures.

[0004] According to the present invention, it is proposed to provide an electric axle drive with two pumps. A first pump draws oil from a primary oil sump directly into a pressurized oil line for cooling and / or lubricating components of the electric axle drive. If there is a risk that the primary oil level in the primary oil sump is too low to ensure oil suction by the first pump, particularly during lateral and / or longitudinal accelerations, a second pump draws oil from a secondary oil sump into the primary oil sump to raise its primary oil level to a sufficiently high level.

[0005] In this context, according to one aspect of the invention, an electric axle drive is provided for propelling a motor vehicle. An electric axle drive can be understood as a system for transmitting torque from an electric motor to the drive wheels of a motor vehicle. The electric axle drive can comprise various components that transmit the torque, such as a gearbox, a differential, and axle shafts. In other words, an electric axle drive is a drive system in which one or more electric motors are used to directly drive the wheels of a vehicle via an axle. Electric axle drives are used in battery electric vehicles (BEVs), hybrid electric vehicles (HEVs), and plug-in hybrid electric vehicles (PHEVs). Electric axle drives use electric motors as their drive source.These electric motors can be mounted on the wheels or located in other parts of the vehicle and transmit their energy to the wheels via a drive shaft. Unlike vehicles with combustion engines and transmissions, power transmission in electric axle drives typically occurs without the use of a conventional gearbox. Electric motors can deliver high torque across a wide speed range, reducing the need for complex transmission systems. A motor vehicle can be defined as a vehicle powered by a motor, such as a car (passenger car) weighing less than 3.5 tons, a motorcycle, a scooter, a moped, a bicycle, an e-bike or pedelec (acronym for Pedal Electric Cycle), a bus, or a truck (e.g., weighing more than 3.5 tons), or even a rail vehicle, a ship, or an aircraft such as a helicopter or airplane.

[0006] The axle drive can include a first pump. A pump can be understood as a device for generating fluid flow through mechanical work. In an electric axle drive, the pump serves to circulate oil to cool and / or lubricate the electric motor and gearbox. The pump can have various designs, such as a gear pump, a centrifugal pump, or a vane pump. The axle drive can also include a second pump. Furthermore, the axle drive can include a first internal chamber. The first internal chamber can, in particular, be formed by a housing of the electric axle drive. The first internal chamber is a cavity. The axle drive can also include a second internal chamber, a pressurized oil line, an electric motor, and a gearbox.

[0007] An electric motor is an electrical device that converts electrical energy into mechanical energy, typically in the form of torque and rotation. In an electric axle drive, the motor can serve as the primary drive source to propel the vehicle. The electric motor is located within the first interior space, which is formed, in particular, by the housing of the electric axle drive. A transmission can be understood as a mechanical system used to vary the speed and torque between a drive source (e.g., the electric motor) and a load (e.g., the wheels of a vehicle). The transmission can be used to modify the torque of the electric motor to meet the requirements for the speed and power of the vehicle.The transmission is located in particular within the second interior space, which is formed in particular by the housing of the electric axle drive.

[0008] The first pump may be designed to draw oil from the first interior space and deliver it to the pressurized oil line to cool and / or lubricate the electric motor and gearbox. The pressurized oil line runs alongside the electric motor and the gearbox of the electric transmission. Thus, oil flowing through the pressurized oil line can absorb heat from the electric motor and gearbox. Furthermore, the pressurized oil line may have a first outlet near the electric motor. Oil can exit the pressurized oil line from this first outlet and come into contact with the electric motor to cool and / or lubricate it. The pressurized oil line may also have a second outlet near the gearbox. Oil can exit the pressurized oil line from this second outlet and come into contact with the gearbox to cool and / or lubricate it.

[0009] Furthermore, it may be provided that oil from the pressurized oil line forms a primary oil sump in the first interior space and a secondary oil sump in the second interior space. This oil has previously cooled and / or lubricated the electric motor and the transmission. For example, the oil has exited the first and second outlets of the pressurized oil line, wetted the electric motor and the transmission, and then, due to gravity, has sunk into a base area of ​​the electric axle drive to form the primary and secondary oil sumps.

[0010] Furthermore, the second pump may be configured to draw oil from the secondary oil sump and supply it to the primary oil sump. For example, if the electric axle drive is subjected to lateral and / or longitudinal acceleration at a specific altitude, the second pump can refill the primary oil sump with oil from the secondary oil sump. In this way, the second pump contributes to maintaining the oil intake by the first pump. Alternatively or additionally, the primary oil sump can also be refilled with oil from the secondary oil sump if the secondary oil level exceeds a defined limit. In this context, the second pump acts as a secondary pump to reduce drag torque by preventing or at least reducing churning of rotating components in the secondary oil sump.The second pump delivers oil back to the first pump after it has passed the cooling points and / or lubrication points, particularly when no lateral acceleration and / or longitudinal acceleration acts on the electric axle drive.

[0011] A partition wall can prevent oil from flowing from the first interior space into the second. In one embodiment, the axle drive also includes a partition wall.

[0012] The partition can be formed, for example, by the housing of the electric axle drive. The partition extends, in particular, in a vertical direction along the electric axle drive, specifically from an upper wall to a lower wall of the housing. This embodiment is characterized in particular by the fact that the partition separates the first interior space from the second. The partition ensures that the first interior space is not fluidically connected to the second. Fluid, especially oil, which collects in a bottom region of the first interior space to form a primary oil sump, cannot pass through the partition and flow into the second interior space. This contributes to ensuring that, even when lateral and / or longitudinal accelerations occur, the oil level within the first interior space is always high enough for the first pump to draw in oil.

[0013] The second pump can be driven by either the electric motor or the gearbox. In one embodiment, the second pump is driven by the electric motor or gearbox. For example, a shaft or gear of the gearbox can be used to drive the second pump. Alternatively, a rotor shaft of the electric motor can be used to drive the second pump. This eliminates the need for an additional motor to drive the second pump, saving components, installation space, and costs.

[0014] The second pump can be a component of an element of the electric axle drive that is dependent on the input or output speed. In other words, the second pump can be integrated into the electric motor or gearbox. In one embodiment, the electric motor or gearbox at least partially forms the second pump. Thus, the second pump is integrated into the electric motor or gearbox. This allows at least some components of the second pump to be formed by the electric motor or gearbox, thereby further reducing the number of components, installation space, and costs.

[0015] The second pump can be integrated into a transmission stage of the gearbox, in particular arranged coaxially or parallel to an output shaft (especially a rotor shaft) of the electric motor. In this context, one embodiment provides that a transmission stage of the gearbox at least partially forms the second pump. For example, an output shaft or a gear mounted thereon of the gearbox can form part of the second pump.

[0016] The second pump can comprise a rotating component and a stationary component. In particular, the stationary component can enclose the rotating component and have at least one oil supply and at least one oil discharge. In this context, one embodiment provides that the second pump comprises a pump rotor with guide vanes. The pump rotor rotates during operation of the electric axle drive, with the guide vanes conveying oil. The pump rotor can be designed as a single piece or in multiple parts, particularly two pieces. The second pump can, in particular, be a centrifugal pump. Furthermore, it is provided that the second pump comprises a pump housing that surrounds the pump rotor. The pump housing is stationary, i.e., it does not rotate. Oil conveyed by the guide vanes is conveyed to the pump housing.Furthermore, this embodiment is characterized by the fact that the pump housing has an inlet and an outlet. The oil conveyed by the guide vanes can enter the pump housing via the inlet, be deflected there, and directed to the outlet. The oil can then leave the pump housing via the outlet to flow downstream into the first internal chamber, where it can refill the primary oil sump.

[0017] The pump rotor can be integrated, in particular, into an output gear of the transmission. In one embodiment, the pump rotor is formed by an output gear mounted on an output shaft of the transmission. The output shaft is located, in particular, in a lower region of the electric axle drive. There, the oil can easily form the secondary oil sump, and the guide vanes of the pump rotor can easily collect and pump this oil. When the pump rotor rotates, the guide vanes can accelerate the oil in both a circumferential and a radial direction, thus generating a delivery pressure and a delivery volume. The oil can be pumped from an inner diameter to an outer diameter. This can be achieved depending on the geometry and rotational speed of the pump rotor, as well as on the density and flow rate of the supplied oil.

[0018] Rotating parts of the electric axle drive can also be encapsulated, in particular by means of a housing (oil collection tray). In this context, one embodiment provides that the axle drive further comprises a housing. This embodiment is characterized in particular by the fact that the housing surrounds a rotating component of the electric axle drive, thus separating the rotating component from the secondary oil sump. The rotating component therefore does not churn in the oil that forms the secondary oil sump. This reduces churning losses and increases the efficiency of the electric axle drive. Furthermore, it improves the exchange of oil between the secondary and primary oil sumps.

[0019] At least one of the housings can encapsulate the output gear. In this context, one embodiment provides that the rotating component comprises an output gear of the transmission. The output gear is located, in particular, in a lower region of the electric axle drive, where the risk of oil contamination is highest. The housing separates the area around the output gear from the secondary oil sump. A smaller quantity of oil can collect in this area, or within the housing, compared to the secondary oil sump. The housing prevents the rotation of the output gear from contamination of the secondary oil sump, thereby increasing the efficiency of the electric axle drive.

[0020] Furthermore, an oil return line can be provided or incorporated. The oil return line can lead from the second interior space to the first interior space. Particularly in situations without lateral and / or longitudinal acceleration, oil can flow from the secondary oil sump to the primary oil sump via the oil return line (without the aid of the second pump), thus equalizing the level between the two oil sumps. In this context, one embodiment provides that the axle drive also includes an oil return line. This embodiment is particularly characterized by the fact that the oil return line connects the first interior space to the second interior space in such a way that oil can flow from the secondary oil sump to the primary oil sump when no lateral and / or longitudinal acceleration acts on the electric axle drive.

[0021] In the following, exemplary embodiments of the invention are explained in more detail with reference to the schematic drawing, wherein identical or similar elements are provided with the same reference numeral. Here, [the following is shown] Fig. 1. A top view of a motor vehicle's drivetrain, Fig. 2 a longitudinal section view of a first example of an electric axle drive of the motor vehicle according to Fig. 1 in a first operating state without lateral acceleration and without longitudinal acceleration, wherein a fluid circuit cools and / or lubricates components of the electric axle drive, Fig. 3 a longitudinal section view of the electric axle drive according to Fig. 2 in a second operating state with lateral acceleration and / or longitudinal acceleration, Fig. 4 a longitudinal section view of a second example of an electric axle drive of the motor vehicle according to Fig. 1 in a first operating state without lateral acceleration and without longitudinal acceleration, wherein a fluid circuit cools and / or lubricates components of the electric axle drive, Fig. 5 a longitudinal section view of the electric axle drive according to Fig. 4 in a second operating state with lateral acceleration and / or longitudinal acceleration, Fig. 6 a longitudinal section view of a third example of an electric axle drive of the motor vehicle according to Fig. 4 in a first operating state without lateral acceleration and without longitudinal acceleration, wherein a fluid circuit cools and / or lubricates components of the electric axle drive, Fig. 7 a side view (left) and a front view (right) of a pump rotor of the electric axle drive according to Fig. 6, Fig. 8 a side view (left) and a front view (right) of a pump housing of the electric axle drive according to Fig. 6, Fig. 9 the electric axle drive to Fig. 6 in a first operating state and Fig. 10 the electric axle drive to Fig. 6 in a second operating state.

[0022] Fig. Figure 1 shows, purely by way of example, a motor vehicle 1, which could be, for example, a passenger car or a commercial vehicle. The motor vehicle 1 has a drive train 2, which is explained in more detail below and which, in the exemplary embodiment according to Fig. 1 optionally enables a switchable and switchable all-wheel drive. The drivetrain 2 comprises a drive unit 3. In the illustrated embodiment, the drive unit 3 comprises a drive motor 4, e.g., an internal combustion engine or an electric motor 12. If the drive motor 4 is an electric motor 12, it can be operated in motor mode to drive the vehicle 1 and in generator mode to charge a battery 5, which can supply the electric motor 12 4 with electrical energy during its motor mode. The drive unit 3 further comprises an automatic transmission 6. In the illustrated embodiment, the drive motor 4 permanently drives two front wheels 8, which are mounted on a front axle 9, via the automatic transmission 6 and a front axle differential 7.

[0023] The drive train 2 can, alternatively or additionally to the described front axle drive, have at least one optionally switchable and switchable electric axle drive 10 for driving a rear axle 11. In the by Fig. In the embodiment shown in Figure 1, the electric axle drive 10 comprises an electric motor 12 and a gearbox 13. The battery 5 provides electrical energy for operating the electric motor 12. The electric motor 12 can drive the rear axle 11 via the gearbox 13 (e.g., a two-stage gearbox 13) and via a rear axle differential 14. Two front wheels are mounted non-rotatably on the rear axle 11 and rotate with it.

[0024] Fig. 2 and Fig. Figure 3 shows details of a first example of an electric axle drive 10 for the motor vehicle 1 according to Fig. 1. The electric motor 12 is arranged on a drive side 16 of the electric axle drive 10 with respect to a horizontal direction x. The gearbox 13 is arranged on an output side 17 of the electric axle drive 10 opposite the drive side 16 with respect to the horizontal direction x. A rotor shaft 60 of the electric motor 12 is coupled to a drive shaft 61 of the gearbox 13. The electric motor 12 and the gearbox 13 are housed within a casing 18 of the electric axle drive 10. The casing 18 comprises a first interior space 19 (traction motor compartment), which is located on the drive side 16 and which houses the electric motor 12. The casing 18 further comprises a second interior space 20 (wheelset compartment), which is located on the output side 17 and which houses the gearbox 13.

[0025] A partition 21 extends in a vertical direction y of the electric axle drive 10 from an upper wall 22 of the housing 18 downwards, over an upper region 23 and a middle region 24 of the housing 18, partially into a lower region 25 of the housing 18. The partition 21 separates the first interior space 19 from the second interior space 20 in the upper region 23, in the middle region 24, and also partially in the lower region 25 of the housing 18. The lower region 25 includes a floor region 26. The floor region 26 begins in the vertical direction y where the partition 21 ends in the lower region 25. Within the floor region 26, the partition 21 does not separate the first interior space 19 from the second interior space 20.Thus, the first interior space 19 and the second interior space 20 are connected in the floor area 26, so that a fluid can flow from the first interior space 19 into the second interior space 20 and vice versa in the floor area 26.

[0026] The electric axle drive 10 comprises a first pump 27, which is driven by an electric motor 28. The first pump 27 draws a fluid, in the illustrated embodiment oil, from an oil sump 29. The oil sump 29 is formed in the bottom region 26 of the housing 18. The oil sump 29 extends in the horizontal direction x into the first interior space 19 and into the second interior space 20. In the illustrated embodiment, the oil sump 29 extends in the horizontal direction x over the entire first interior space 19 and over the entire second interior space 20. In the vertical direction y, the oil sump 29 is closed off at the top by an oil level 30. The first pump 27 draws oil from the oil sump 29. For this purpose, the first pump 27 has a suction line. The suction line extends downwards in the vertical direction y. At one lower end of the intake pipe, it has an inlet 32 ​​for oil. The inlet 32 ​​is located in the area defined by Fig. Figure 2 shows the first operating state of the electric axle drive 10 or motor vehicle 1 below the oil level 30 of the oil sump 29. Thus, the first pump 27 can draw in oil. In the first operating state according to Fig. 2 the motor vehicle 1 moves in such a way that the electric axle drive 10 is not subjected to any longitudinal or lateral accelerations.

[0027] The first pump 27 delivers the oil drawn from the oil sump 29 into a pressure oil line 33. The pressure oil line 33 runs along the drive side 16 and the output side 17 along components of the electric axle drive 10 that require cooling and / or lubrication. For example, on the drive side 16, the pressure oil line 33 runs along the electric motor 12 to cool it indirectly. In the area of ​​the electric motor 12 and within the first interior space 19, the pressure oil line 33 may have a first outlet 34. Oil can exit the pressure oil line 33 through the first outlet 34 and enter the first interior space 19, where it comes into contact with the electric motor 12. This allows the electric motor 12 to be cooled and / or lubricated directly. Further downstream, on the output side 17, the pressure oil line 33 has a second outlet 35.Oil conveyed through the pressure oil line 33 can exit the pressure oil line 33 via the second outlet 35 and enter the second interior space 20. Within the second interior space 20, the oil can be guided along the gearbox 13, so that the gearbox 13, e.g. its gear sets 36 and bearings 37, is cooled and / or lubricated.

[0028] Oil that has escaped from the first outlet 34 and, as described above, has cooled and / or lubricated the electric motor 12, flows or drips, particularly by gravity, within the first interior space 19 into the floor area 26 and forms a first part of the oil sump 29. Similarly, oil that has escaped from the second outlet 35 and, as described above, has cooled and / or lubricated the gearbox 13, flows or drips, particularly by gravity, within the second interior space 20 into the floor area 26 and forms a second part of the oil sump 29 there. Fig. In the operating condition shown in Figure 2, the oil level 30 in the vertical direction y is high enough that the first pump 27 can draw in oil via the inlet 32 ​​and an oil flow can be maintained within the pressure oil line 33. However, churning occurs in the Fig. In the operating condition shown in Figure 2, rotating parts of the electric axle drive 10, e.g., the gear set 36 of the gearbox 13, are immersed in the oil of the oil sump 29. This has a negative impact on the efficiency of the electric axle drive 10. Furthermore, it results in a less than ideal oil flow from the first chamber 19 to the second chamber 20.

[0029] Fig. Figure 3 shows a second operating state of the motor vehicle 1. In the second operating state, a lateral acceleration acts on the electric axle drive 10. Alternatively or additionally, in the second operating state, according to Fig. 3. A longitudinal acceleration also acts on the electric axle drive 10. Oil that has escaped from the first outlet 34 and, as described above, has cooled and / or lubricated the electric motor 12, flows or drips, particularly by gravity, within the first interior space 19 into the floor area 26 and forms a first part of the oil sump 29. Furthermore, oil that has escaped from the second outlet 35 and, as described above, has cooled and / or lubricated the transmission 13, flows or drips, particularly by gravity, within the second interior space 20 into the floor area 26 and causes an increase in the oil level 30 of the oil sump 29.

[0030] Due to lateral and / or longitudinal acceleration, the oil that collects within the first interior space 19 does not remain within the first interior space 19, but flows into the second interior space 20. Consequently, the oil level 30 within the first interior space 19 may drop to such an extent that the inlet 32 ​​of the intake line is no longer below the oil level 30 and thus no longer immerses in the oil sump 29. In the case of Fig. In the operating condition shown in Figure 3, almost all the oil collects within the second chamber 20, while the first chamber 19 runs dry. In the Fig. In the second operating condition shown in Figure 3, no oil at all flows from the second interior space 20 into the first interior space 19. Consequently, the first pump 27 can no longer draw in oil and maintain the oil flow within the pressure oil line 33. This can lead to overheating of the electric motor 12. Furthermore, there is a risk of damage to the lubrication points of the electric axle drive 10. Additionally, sloshing occurs in the area caused by Fig. In the operating state shown in Figure 3, rotating parts of the electric axle drive 10, e.g., the gear set 36 of the transmission 13, are immersed in the oil of the oil sump 29. Due to the increased oil level 30 within the second interior space 20 compared to the first operating state, this splashing is reduced in the second operating state. Fig. 3 more intense, which has a particularly negative impact on the efficiency of the electric axle drive 10.

[0031] Fig. 4 and Fig. 5 show details of a second example and Fig. 6 of a third example of an electric axle drive 10 for the motor vehicle 1 according to Fig. 1. The electric motor 12 is arranged on a drive side 16 of the electric axle drive 10 with respect to a horizontal direction x. The gearbox 13 is arranged on an output side 17 of the electric axle drive 10 opposite the drive side 16 with respect to the horizontal direction x. The electric motor 12 and the gearbox 13 are housed within a casing 18 of the electric axle drive 10. The casing 18 comprises a first interior space 19 (traction motor compartment), which is located on the drive side 16 and which houses the electric motor 12. The casing 18 further comprises a second interior space 20 (wheelset compartment), which is located on the output side 17 and which houses the gearbox 13.

[0032] A according to Fig. 4 and Fig. 5 one-piece and according to Fig. 6. A multi-part partition 21 extends in a vertical direction y of the electric axle drive 10 from an upper wall 22 of the housing 18 downwards, over an upper area 23, a middle area 24 of the housing 18 and according to Fig. 4 and Fig. 5 not merely partially, but over an entire lower area 25 of the housing 18 up to a lower wall 38 of the housing 18. In contrast, the partition 21 in the example is Fig. 6 in the area of ​​an output shaft 39 of the electric axle drive 10 is interrupted by the output shaft 39. The partition 21 separates the first interior space 19 from the second interior space 20, specifically in the upper area 23, in the middle area 24, and according to Fig. 4 and Fig. 5 in the entire lower area 25 of the housing 18. In the example according to Fig. 6. The output shaft 39 partially closes off the first interior space 19 from the second interior space 20 in the lower area 25. Thus, the first interior space 19 and the second interior space 20 are separated in the examples according to Fig. 4 to 6 are completely separated from each other, so that - not without further ado (see below) - a fluid can flow from the first interior space 19 into the second interior space 20 and vice versa.

[0033] The electric axle drive 10 comprises a first pump 27, which is driven by an electric motor 28. The first pump 27 draws a fluid, in the illustrated embodiment oil, from a primary oil sump 40. The primary oil sump 40 is formed within the first interior space 19 in a bottom region 26 of the housing 18. The bottom region 26 extends upwards from the lower wall 38 of the housing 18 in the vertical direction y into the lower region 25 of the housing 18. The primary oil sump 40 extends in the horizontal direction x only within the first interior space 19 and not within the second interior space 20, since the first interior space 19 and the second interior space 20 are separated from each other in the region of the lower wall 38 by the partition 21. In the vertical direction y, the primary oil sump 40 is capped at the top by a primary oil level 41. The first pump 27 draws oil from the primary oil sump 40.The first pump 27 has a first suction line 31. The first suction line 31 extends downwards in the vertical direction y. At a lower end of the first suction line 31, it has a primary inlet 42 for oil. The primary inlet 42 is located in the area defined by... Fig. The operating states of the electric axle drive 10 and the motor vehicle 1 shown in Figures 4 to 6 are below the primary oil level 41 of the primary oil sump 40. Thus, the first pump 27 can draw in oil. In the first operating state according to Fig. 4 and Fig. 6 the motor vehicle 1 moves in such a way that the electric axle drive 10 is not subjected to any longitudinal or lateral accelerations.

[0034] The first pump 27 delivers the oil drawn from the primary oil sump 40 into a pressure oil line 33. The pressure oil line 33 runs along the drive side 16 and the output side 17 along components of the electric axle drive 10 that require cooling and / or lubrication. For example, on the drive side 16, the pressure oil line 33 runs along the electric motor 12 to cool it indirectly. In the area of ​​the electric motor 12 and within the first interior space 19, the pressure oil line 33 may have a first outlet 34. Oil can exit the pressure oil line 33 through the first outlet 34 and enter the first interior space 19, where it comes into contact with the electric motor 12. This allows the electric motor 12 to be cooled and / or lubricated directly. Further downstream, on the output side 17, the pressure oil line 33 has a second outlet 35.Oil conveyed through the pressure oil line 33 can exit the pressure oil line 33 via the second outlet 35 and enter the second interior space 20. Within the second interior space 20, the oil can be guided along the gearbox 13, so that the gearbox 13, e.g. its gear sets 36 and bearings 37, is cooled and / or lubricated.

[0035] Oil that has escaped from the first outlet 34 and, as described above, has cooled and / or lubricated the electric motor 12, flows or drips, particularly by gravity, within the first interior space 19 into the bottom area 26, forming the primary oil sump 40, which is closed off in the vertical direction y upwards by a primary oil level 41. Similarly, oil that has escaped from the second outlet 35 and, as described above, has cooled and / or lubricated the gearbox 13, flows or drips, particularly by gravity, within the second interior space 20 into the bottom area 26, forming a secondary oil sump 43, which is closed off in the vertical direction y upwards by a secondary oil level 52. In the area defined by Fig. In the operating condition shown in Figure 4, the primary oil level 41 is high enough in the vertical direction y that the first pump 27 can draw oil via the primary inlet 42 and an oil flow can be maintained within the pressure oil line 33. An oil return line 46 runs in the bottom section 26. The oil return line 46 connects the second chamber 20 with the first chamber 19. Oil that has collected in the secondary sump can flow via the oil return line 46 into the primary oil sump 40 within the first chamber 19.

[0036] To achieve this through Fig. 3 and Fig. To prevent the mixing of rotating parts of the electric axle drive 10, e.g., the gear set 36 of the transmission 13, in the oil of the secondary oil sump 43, as shown in Figure 4, the output gear 44 of the output shaft 39, mounted on the output shaft 39, is encapsulated. For this purpose, the electric axle drive 10 has at least one housing 45 (oil collection tray). Fig. Figures 4 to 6 each show an example of a formwork 45 arranged within the second interior space 20. The formwork 45 surrounds the output gear 44 in a section below the output shaft 39. The formwork 45 separates the output gear 44 from the secondary oil sump 43. This prevents rotating components (in the examples shown, the output gear 44) from splashing in oil, thereby increasing the efficiency of the electric axle drive 10 and improving the oil flow from the secondary oil sump 43 to the primary oil sump 40, as described below.

[0037] Fig. Figure 5 shows a second operating state of the motor vehicle 1. In the second operating state, a lateral acceleration acts on the electric axle drive 10. Alternatively or additionally, in the second operating state, according to Fig. 5. A longitudinal acceleration also acts on the electric axle drive 10. Oil that has escaped from the first outlet 34 and, as described above, has cooled and / or lubricated the electric motor 12, flows or drips, particularly by gravity, within the first interior space 19 into the floor area 26 and forms the primary oil sump 40. Furthermore, oil that has escaped from the second outlet 35 and, as described above, has cooled and / or lubricated the transmission 13, flows or drips, particularly by gravity, within the second interior space 20 into the floor area 26 and forms the secondary oil sump 43 there.

[0038] Due to the lateral acceleration and / or the longitudinal acceleration, the oil collecting within the first interior space 19 moves towards the partition 21, but does not flow as in Fig. 3 into the second interior space 20, since the partition wall 21 does this in the exemplary embodiments according to Fig. 4 to 6 prevented. In the operating state after Fig. 5. The oil backs up at the partition wall 21. The primary oil level 41 rises in the area of ​​the partition wall 21 and falls in an area below the primary pump. The partition wall 21 already reduces the risk that so much oil is forced towards the output side 17 that the primary inlet 42 of the primary pump draws in air instead of oil. In the second operating state, oil flows via the oil return line 46 to Fig. 5. No oil from the secondary oil sump 43 into the primary oil sump 40. It can still occur that the oil level 30 within the first interior space 19 in the area of ​​the primary inlet 42 of the intake line drops to such an extent that the primary inlet 42 of the intake line is no longer below the oil level 30 and thus no longer immerses in the oil sump 29. To counteract this, the following is carried out in the Fig. In the second operating state shown in Figure 5, the primary oil sump 40 is filled with oil from the secondary oil sump 43, ensuring that the first pump 27 can always draw oil via the primary inlet 42 and maintain the oil flow within the pressure oil line 33. This prevents overheating of the electric motor 12 and damage to the lubrication points.

[0039] The electric axle drive 10 has a second pump 47. The second pump 47 is located within the second interior space 20. Within the second interior space 20, the second pump 47 draws oil from the secondary oil sump 43 and delivers it within the first interior space 19 to the primary oil sump 40. For this purpose, the second pump 47 has a second suction line 48. In this exemplary embodiment, the second suction line 48 extends according to Fig. 4 and Fig. 5 in the vertical direction y downwards. At one end of the second suction line 48, facing away from the second pump 47, it has a secondary inlet 49 for oil. The secondary inlet 49 is located in the Fig. In the operating states of the electric axle drive 10 or motor vehicle 1 shown in Figures 4 to 6, the level of the secondary oil is always below the secondary oil level 52 and enters the secondary oil sump 43. Thus, the second pump 47 can always draw in oil, regardless of whether the electric axle drive 10 is in the first or second operating state. The second pump 47 has a secondary pressure line 50, which connects the second pump 47 to the first interior space 19. The secondary pressure line 50 has a secondary outlet 51 at its end furthest from the second pump 47. Oil that has been drawn from the secondary oil sump 43 by the second pump 47 and pumped into the secondary pressure line 50 can exit the secondary pressure line 50 via the secondary outlet 51 and enter the first interior space, where it can collect in the primary oil sump 40, thus raising the primary oil level 41.

[0040] The second pump 47 can be arranged in a transmission stage 62 of the gearbox 13 and, for example, be driven by the output gear 44 of the gearbox 13. In particular, the second pump 47 can be a centrifugal pump driven by Fig. 4 to 6 and in detail by Fig. 7 and Fig. Figure 8 shows that the second pump 47 can have a pump rotor 53 with guide vanes 54. The pump rotor 53, including its guide vanes 54, can be integrated into the output gear 44. The pump rotor 53 rotates in a direction 55, whereby the guide vanes 54 pump oil into the secondary inlet 49 of the second suction line 48. Fig. Figure 8 shows that the second pump 47 can further comprise a non-rotating, stationary pump housing 56. The pump housing 56 can, for example, be formed by the formwork 45, which is shown by Fig. Figure 6 shows that the pump housing 56 can include a pressure kidney 57, an inlet 58, and an outlet 59. When the pump rotor 53 rotates, the guide vanes 54 pump oil from the secondary oil sump 43 through the inlet 58 into the pump housing 56. There, it is guided circumferentially along the pressure kidney 57 and exits the pump housing 56 via its outlet into the secondary pressure line 50 in the direction of the first interior space 19 to refill its primary oil sump 40.

[0041] Fig. Figure 9 shows the electric axle drive. Figure 10 shows the electric axle drive. Fig. 6 in the first operating state. In this state, the electric axle drive 10, or the vehicle 1, is stationary in the left-hand illustration. Due to leaks, the primary oil level 41 and the secondary oil level 52 are at the same level, and the pump housing 56 is also filled with oil to the same level. In the right-hand illustration, the vehicle 1, or the electric axle drive 10, is in operation, but without any dynamic movement. The primary oil level 41 and the secondary oil level 52 are at the same level. Oil from the secondary oil sump 43 flows via the oil return line 46 into the primary oil sump 40. Oil that has collected in the housing 45, or in the pump housing 56, due to leaks, is emptied into the first interior space 19 by means of the second pump 47. Fig. Figure 10 shows the electric axle drive 10 after Fig. 6 in the second operating state. In this state, a lateral acceleration acts on the electric axle drive 10 or on the motor vehicle 1. In the left-hand illustration, according to Fig. In the diagram 10, the lateral acceleration acts to the left, i.e., in the direction of the output side 17. The primary oil level 41 differs from the secondary oil level 52. The second pump 47 transfers oil from the secondary oil sump 43 into the primary oil sump 40. In the diagram on the right, a lateral acceleration to the right (i.e., in the direction of the input side 16) acts on the vehicle 1 or on the electric axle drive 10. Here, too, the primary oil level 41 is not at the same level as the secondary oil level 52. Oil from the secondary oil sump 43 flows into the primary oil sump 40 via the oil return line 46. Reference sign x horizontal direction y vertical direction 1 motor vehicle 2 Powertrain 3 Drive unit 4 Drive motor 5 batteries 6 automatic transmissions 7 front axle differential gears 8 front wheels 9 Front axle 10 electric axle drive 11 Rear axle 12 electric motor 13 gearboxes 14 Rear axle differential gears 15 rear wheel 16 Drive side 17 Output side 18 cases 19 first interior 20 second interior 21 Partition wall 22 upper wall 23 upper area 24 middle range 25 lower range 26 Floor area 27 first pump 28 Electric motor 29 Oil sump 30 oil levels 31 first intake pipe 32 Entrance 33 Pressure oil line 34 first outlet 35 second outlet 36 wheelset 37 warehouses 38 lower wall 39 Output shaft 40 Primary oil sump 41 Primary oil level 42 Primary input 43 Secondary oil sump 44 Output gear 45 formwork 46 Oil return line 47 second pump 48 second intake pipe 49 Secondary input 50 Secondary pressure line 51 Secondary outlet 52 Secondary oil level 53 Pump rotor 54 Guide vane 55 Direction of rotation 56 Pump housings 57 Pressure kidney 58 Inflow 59 Procedure 60 Rotor shaft 61 Drive shaft 62 translation level

Claims

[1] Electric axle drive (10) for driving a motor vehicle (1), comprising the electric axle drive (10) - a first pump (27), - a second pump (47), - a first interior (19), - a second interior space (20), - a pressurized oil line (33), - an electric motor (12), - a gearbox (13), wherein - the first pump (27) is designed to draw oil from the first interior (19) and deliver it to the pressure oil line (33) to cool and / or lubricate the electric motor (12) and the gearbox (13), - Oil from the pressure oil line (33) forms a primary oil sump (40) in the first interior space (19) and a secondary oil sump (43) in the second interior space (20), and - the second pump (47) is designed to draw oil from the secondary oil sump (43) and supply it to the primary oil sump (40). [2] Electric axle drive (10) according to claim 1, the electric axle drive (10) further comprising a partition (21) wherein the partition (21) separates the first interior space (19) from the second interior space (20). [3] Electric axle drive (10) according to claim 1 or 2, wherein the second pump (47) is driven by the electric motor (12) or the gearbox (13). [4] Electric axle drive (10) according to claim 3, wherein the electric motor (12) or the transmission (13) at least partially forms the second pump (47). [5] Electric axle drive (10) according to claim 4, wherein a transmission stage (62) of the transmission (13) forms at least part of the second pump (47). [6] Electric axle drive (10) according to claim 5, wherein - the second pump (47) comprises a pump rotor (53) with guide vanes (54), - the second pump (47) includes a pump housing (56) which surrounds the pump rotor (53) and - the pump housing (56) has an inlet (58) and an outlet (59). [7] Electric axle drive (10) according to claim 6, wherein the pump rotor (53) is formed by an output gear (44) which is mounted on an output shaft (39) of the transmission (13). [8] Electric axle drive (10) according to one of the preceding claims, the electric axle drive (10) further comprising a formwork (45), wherein the formwork (45) surrounds a rotating component of the electric axle drive (10) such that the formwork (45) separates the rotating component from the secondary oil sump (43). [9] Electric axle drive (10) according to claim 8, wherein the rotating component comprises an output gear (44) of the transmission (13). [10] Electric axle drive (10) according to claim 1, the electric axle drive (10) further comprising an oil return line (46), wherein the oil return line (46) connects the first interior space (19) with the second interior space (20) in such a way that oil can flow from the secondary oil sump (43) into the primary oil sump (40) when no lateral acceleration and / or no longitudinal acceleration acts on the electric axle drive (10).

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