Device and method for controlling cooling / lubricating oil flow and its initial flow temperature as needed in electric traction drive

Abstract

The invention relates to a device for controlling the initial flow temperature of a cooling / lubricating oil flow as required in an electric traction drive, comprising an electrically controllable motor-pump unit and a hydraulic unit, the motor-pump unit being actuatable in two directions of rotation, namely a first direction of rotation and a second direction of rotation opposite the first direction of rotation, a first pressure level and a second pressure level higher than the first pressure level can be set on the motor-pump unit via a rotational speed adjustment in the first or second rotational direction, the motor-pump unit being connected via a hydraulic unit to a plurality of fluid outputs of the first, second and third partial volume flows, the fluid output is connected at least to the stator and / or rotor and / or to the transmission of the electric drive machine for cooling and / or heating and / or lubrication, comprising a heat exchanger to which the first partial volume flow is not connected, the direction of rotation and the pressure level of the motor-pump unit can be set via the electric control unit and three different operating modes can be set depending on them.

Description

Technical Field

[0001] The invention relates to a device and a method for controlling the cooling / lubricating oil flow and its initial flow temperature in an electric traction drive as required, the device comprising an electrically controllable motor-pump unit and a hydraulic device, wherein the motor-pump unit can be controlled in two directions of rotation, and wherein the motor-pump unit is connected to a plurality of fluid output ends via a heat exchanger, wherein the fluid output ends are connected at least to the stator of the motor, the rotor of the motor and the transmission device for cooling and / or heating and / or lubrication. Background Art

[0002] Electric traction drives consist essentially of an electric motor, a converter and a reducer. The maximum power, service life and efficiency of these components are decisively determined by the cooling concept selected. The trend towards higher and higher power within the same installation space and the increasing integration density inevitably require improvements in cooling and thermal management.

[0003] Powerful electric drive systems with high energy density are usually equipped with electrically operated oil pumps and oil-water heat exchangers for cooling purposes. Oil pumps driven by means of brushless DC motors (BLDC motors) are usually used. As a preferred pump type, rotary positive displacement pumps are used in the embodiment as gear ring pumps, cycloidal rotor pumps.

[0004] Here, the delivery volume flow provided by the electric oil pump is mainly used to cool the temperature-critical active components (stator and / or rotor) of the electric machine as required. For this purpose, the electrically operated oil pump is switched on and off as required and / or operated in a speed-controlled manner.

[0005] The cooling and lubrication of the transmission components usually takes place passively, wherein for this purpose the conveying action of the differential spur gear or the intermediate shaft spur gear is used in combination with a suitable housing that acts as an oil guide. This is associated with a limited conveying action that is dependent on the vehicle speed or the gear speed and the fluid dynamic losses (splash losses) that are associated therewith, which are highly dependent on the speed and the oil temperature.

[0006] An increase in the overall efficiency of the electric drive system can be achieved by actively supplying the transmission with a cooling oil volume flow / lubricating oil volume flow provided by an electric oil pump (dry sump lubrication).

[0007] A disadvantage here is that when actively supplying the active components (stator and rotor) and the transmission of the electric machine with the aid of a cooling oil volume flow / lubricating oil volume flow provided by an electric oil pump, the fluid starting flow temperatures of the cooling oil flow / lubricating oil flow into the subsystems "transmission" and "electric machine" cannot be controlled independently of one another, but are instead given by the heat exchanger outlet temperature. Usually, due to the high thermal availability, efforts are made to keep the cooling oil starting flow temperature low for cooling the temperature-critical active components (stator and / or rotor) of the electric drive. In contrast, the starting flow temperature of the partial volume flow for cooling and lubricating the components of the reduction gear and differential can be increased to a higher starting flow temperature in order to reduce viscous friction losses.

[0008] In order to solve the problem, WO 2023 / 133 200 A1 discloses that in a vehicle drive unit having an electric motor and a transmission as subcomponents, separate cooling lubricant circuits are provided for the two subsystems, the cooling lubricant circuits having correspondingly matched compositions and properties of the lubricant. In this case, a separate pump as well as a filter and a cooler are required for each cooling lubricant circuit.

[0009] A device and a method for distributing cooling oil flow / lubricating oil flow as required in an electric traction drive are known from document DE 10 2022 214 389 A1. The device has a motor-pump unit that is controlled in two directions of rotation. The motor-pump unit is connected to a plurality of fluid outlets for partial volume flows via a heat exchanger, which are connected to the stator of the motor, the rotor of the motor and the transmission for cooling, heating and / or lubrication. By means of a hydraulically switchable valve, the liquid outlet is additionally opened when the direction of rotation of the motor-pump unit is reversed. Via the fluid outlet, the partial volume flow is available for the electric travel drive.

[0010] DE 10 2011 118 574 A1 discloses a powertrain cooling device and a method for operating the powertrain cooling device. The powertrain cooling device has a bidirectional pump assembly driven by a pump-electric motor. The pump interfaces of the bidirectional pump assembly are respectively connected to cooling circuits. The flow rate of the coolant introduced into the cooling circuit is set by changing the rotation speed of the pump-electric motor.

[0011] Purpose of the Invention

[0012] The object of the invention is to achieve an improved, required provision of cooling oil flows to the rotor shaft and stator of an electric machine and to transmission components, wherein the electric drive system is to be cost-effective with improved overall efficiency and optimized with regard to the number of components and installation space.

[0013] The object is achieved by a device for controlling the starting flow temperature of a cooling oil flow / lubricating oil flow in an electric traction drive as required, the device having an electrically controllable motor-pump unit and a hydraulic unit, wherein the motor-pump unit can be controlled in two rotational directions, namely in a first rotational direction and in a second rotational direction opposite to the first rotational direction, and wherein a first pressure level and a second pressure level higher than the first pressure level can be set at the motor-pump unit via speed regulation in the first rotational direction or in the second rotational direction, respectively, and wherein the motor-pump unit is connected via the hydraulic unit to a plurality of fluid output ends for a first partial volume flow, a second partial volume flow and a third partial volume flow, the fluid output ends being connected at least to a stator of an electric drive machine, a rotor of the electric drive machine and / or a transmission for cooling and / or heating and / or lubrication, wherein the device comprises a heat exchanger, and wherein the first partial volume flow is not connected to the heat exchanger, and wherein the first partial volume flow can be controlled via the hydraulic unit. The control unit sets the rotation direction and pressure level of the motor-pump unit and is capable of setting three different operating modes according to the rotation direction and the pressure level, characterized in that a first partial volume flow is associated with an inflow to a transmission, a second partial volume flow is associated with an inflow to a rotor, and a third partial volume flow is associated with an inflow to a stator, and the hydraulic unit has a reversing valve connected downstream of a flow path of the motor-pump unit and a subsequent hydraulically controllable valve, preferably a two-position three-way valve, wherein the two-position three-way valve is adjustable from a first position to a second position via a control line and a control pressure, and in the first position of the two-position three-way valve, the volume flow from the motor-pump unit is connected to a heat exchanger via a fluid line, and the output end of the heat exchanger is implemented as a fluid line, which branches into a second partial volume flow and a third partial volume flow, wherein the third partial volume flow flows directly as an inflow to the stator, and wherein the second partial volume flow is directed to the rotor via a hydraulically controllable check valve.

[0014] By means of the device according to the invention for controlling the cooling oil flow / lubricating oil flow in an electric traction drive as required, it is possible in a simple manner and with few hydraulic components to set the fluid starting flow temperature of a partial volume flow to transmission components and to temperature-critical active components (stator and / or rotor) of the electric drive machine.

[0015] The motor-pump unit present on the system side is expanded with simple and cost-effective hydraulic valves, shut-off valves, whereby bidirectional operation of the pump becomes possible. Different volume flow distributions fixedly defined via hydraulic resistance control are thereby achieved with clockwise and counterclockwise rotation of the pump.

[0016] By means of the device according to the invention, which comprises an oil pump installed in a transmission, connected to a hydraulic unit and having a heat exchanger, a lubricating coolant, preferably oil, can be selectively conducted as an oil flow through the heat exchanger or delivered directly into the transmission or to temperature-critical active components (stator and / or rotor).

[0017] As a result, the most efficient state can be always selected by a corresponding operation strategy of the electric oil pump according to the vehicle operation mode.

[0018] According to the invention, temperature-critical active components, such as the stator and / or rotor of an electric drive machine (electric motor), can be actively cooled. In addition, active cooling and lubrication of the transmission is possible or, in other operating modes, passive lubrication of the transmission by slip is also possible.

[0019] Uncooled oil can be conveyed into the transmission since the transmission is arranged on the high-temperature side.

[0020] The partial volume flow can be preset via a throttle plate.

[0021] The hydraulically switchable valve is a hydraulically actuable 3 / 2-way valve.

[0022] The device can be implemented in a robust design by using simple hydraulic shut-off valves and intelligent operating strategies.

[0023] In a development of the invention, the different operating modes can be realized by simple non-return valves and spring-loaded non-return valves, so that a hydraulically actuatable 3 / 2-way valve can be omitted.

[0024] In order to realize different raw flow temperatures for the transmission on the high temperature side and the electric machine with active components, namely the rotor and stator, on the low temperature side, only one motor-pump unit and one heat exchanger are required. This is particularly advantageous in terms of cost and installation space.

[0025] The object is also achieved by means of a method for the required distribution of a cooling oil flow / lubricating oil flow in an electric traction drive.

[0026] Advantageously, different operating modes are provided in order to set the starting flow temperature of the respective partial volume flow at the fluid outlet.

[0027] In this case, three different operating modes can be set by operating the motor-pump unit in the rotational direction A or in the rotational direction B at different pressure levels.

[0028] The solution according to the invention results in the following advantages:

[0029] The invention allows the initial flow temperature of a partial volume flow to be controlled as required in order to increase the efficiency and / or the thermal availability of an electric drive system having a fully or partially oil-cooled electric drive machine.

[0030] Hydraulically actuated valves allow precise control of partial volume flows without requiring additional electrical energy.

[0031] The possibility of adapting the partial volume flows in software provides a high degree of flexibility.

[0032] In combination with intelligent, self-learning software, the desired maximum value in terms of efficiency and / or thermal availability can be achieved depending on the operating mode. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings show:

[0034] Figure 1 A schematic diagram of a cooling lubricant circuit according to the invention is shown with an adjustable fluid start flow temperature for the partial volume flows to the transmission and to the temperature-critical active components (stator and / or rotor) of the electric drive machine,

[0035] Figure 2 A hydraulic circuit diagram of a device according to the invention with a 3 / 2-way valve is shown in a first embodiment,

[0036] Figure 3 shows a hydraulic circuit diagram of a device according to the invention with two separate oil pans and a 3 / 2-way valve in a second embodiment,

[0037] Figure 4 shows a hydraulic circuit diagram of a device according to the invention with two separate oil pans in a third embodiment,

[0038] Figure 5 A signal flow chart showing a method for distributing a cooling oil flow / lubricating oil flow as required in an electric traction drive according to a first embodiment,

[0039] Figure 6 shows the course of the volume flow of the second specific embodiment in a first achievable operating mode,

[0040] Figure 7 shows the course of the volume flow of the second specific embodiment in a second achievable operating mode,

[0041] Figure 8 shows the course of the volume flow of the second specific embodiment in a third achievable operating mode,

[0042] Fig. 9 shows the course of the volume flow of the third specific embodiment in a first achievable operating mode,

[0043] Fig.10 shows the course of the volume flow of the third specific embodiment in a second achievable operating mode; and

[0044] Fig.11 The course of the volume flow of the third specific embodiment is shown in a third achievable operating mode. DETAILED DESCRIPTION

[0045] Figure 1 The schematic diagram shows a cooling lubricant circuit of a device 1 for controlling the cooling oil flow / lubricating oil flow as required in an electric traction drive. The electric traction drive comprises an electric drive machine 2 and a transmission 10 as components connected to the cooling lubricant circuit to be lubricated and / or cooled. As cooling lubricant, oil is preferably used as hydraulic fluid.

[0046] As can be seen from the diagram, the cooling lubricant circulation circuit has a low temperature level (temperature level 2) on the right side on the electric drive machine 2 and a high temperature level (temperature level 1) on the left side on the transmission 10. The division into the low temperature level and the high temperature level is shown by the vertical dashed line. In order to obtain the different fluid flow temperatures, the setting of the corresponding fluid flow temperatures can be achieved via the device 1 according to the invention via a first partial volume flow to the transmission and via a second and third partial volume flow to the temperature-critical active components of the electric drive machine 2. This will be described later according to the attached Figure 2 , Figure 3 and Figure 4 as well as Figures 6 to 11 Detailed description of the hydraulic circuit diagram.

[0047] The electric drive machine 2 has a rotor 3 with a rotor shaft 4 which rotates about its axis of rotation D in a stator 5. The stator 5 has a stator core with a stator winding in a conventional manner, which protrudes axially from the stator core on both end sides as so-called winding heads. The rotor 3 and the stator 5 with the winding heads form the above-mentioned temperature-critical active components of the electric drive component, which can be cooled via the second partial volume flow and the third partial volume flow. The electric drive machine 2 is associated with an oil sump 6.

[0048] The rotor shaft 4 is operatively coupled to the intermediate shaft 8 via a gear pair as an output shaft, and the intermediate shaft 8 is operatively coupled to the transmission 10 via another gear pair, which is operatively coupled to the transmission 10 in the form of a differential. The transmission 10 in the form of a differential has an output shaft 11. The transmission 10 is associated with an oil pan 12.

[0049] So from outside Figure 1It can be seen that a heat exchanger 14 and a hydraulic unit 15 fluidically connected to the heat exchanger via an inlet line 14a and an outlet line 14b and a motor-pump unit 21 are connected on the low-temperature side, the hydraulic unit including a hydraulic valve.

[0050] Proceeding from the hydraulic unit 15 , a fluid line 16 to the transmission 10 and a fluid line 17 to the electric drive machine 2 are provided.

[0051] Fluid line 16 is associated with a first partial volume flow 20' at a high temperature level for cooling / lubricating the transmission 10. Fluid line 17 is associated with a second partial volume flow and a third partial volume flow at a low temperature level. Figure 1 It cannot be seen in the illustration that the fluid line 17 is divided into a second partial volume flow 20 ″ and a third partial volume flow 20 ″′. As will be described in detail below, the second partial volume flow 20 ″ is used for lubrication and cooling of the rotor, and the third partial volume flow 20 ″′ is used for lubrication and cooling of the winding heads of the stator 5 .

[0052] Figure 2 The hydraulic circuit diagram of a device 1 according to the invention for the required control of partial volume flows 20 ′, 20 ″, 20 ′″ and the raw flow temperature is shown in a first embodiment, which has a hydraulic unit 15 , a motor-pump unit 21 and a heat exchanger 14 .

[0053] The cooling lubricant pump 18 is driven by an electric motor 19 which can rotate in two directions of rotation. These two components form an electrically controllable motor-pump unit 21. The direction of rotation of the electric motor and the pump 18 in the clockwise (cw) direction is referred to as the direction of rotation A, and the direction of rotation of the electric motor and the pump 18 in the counterclockwise (ccw) direction is referred to as the direction of rotation B.

[0054] The cooling lubricant pump 18 is connected to an oil sump 27 on the suction side and the pressure side via a first non-return valve 26 ′ and a second non-return valve 26 ″. Depending on the direction of rotation of the pump, one of the two non-return valves 26 ′, 26 ″ is in the open position and the respective other non-return valve is in the blocked position. The connection to the oil sump 27 is effected via a screen or filter element 28 arranged therebetween.

[0055] When the pump 18 is in operation, the entire delivery volume flow provided by the pump 18 is conducted via the switching valve 31 and the hydraulically controllable switching valve 32 in the form of a spring-prestressed 3 / 2-way valve which can be adjusted via the pump pressure present in the control line 33. Figure 2In the first position shown in FIG, the entire delivery volume flow is supplied to the heat exchanger 14 via the fluid line 34. In the second position of the 3 / 2-way valve, the entire delivery volume flow is divided and a first portion is supplied to the heat exchanger 14 via the fluid line 34, wherein this portion of the delivery volume flow can be divided between the rotor shaft RS and the stator winding head WH into a second partial volume flow 20″ and a third partial volume flow 20″′ after the oil flows through the heat exchanger 14. In the flow line of the partial volume flow 20″ to the rotor 3, a hydraulically controllable shut-off valve 36 with a bypass line 37 is provided, which has a throttle plate, and in the inlet to the rotor 3, a throttle plate 38a is provided, which realizes resistance control via a defined flow cross section.

[0056] In the second position of the 3 / 2-way valve 32 , the second part of the delivery volume flow is delivered as the first partial volume flow 20 ′ via the fluid line 16 in which a nonreturn valve 39 is installed and via a throttle plate 38 b in the inlet flow to the transmission GBX, 10 .

[0057] A flow line 22 having a nonreturn valve 23 is provided between the inflow to the stator and the inflow to the gear. The nonreturn valve 23 blocks the flow direction from the fluid line 16 to the inflow to the rotor 3 .

[0058] The motor-pump unit 21 is controlled with respect to the direction of rotation and the pump pressure to be set via an electronic control unit (not shown) which is connected to the data bus. The control unit is connected to the motor 19 of the motor-pump unit 21 via an electrical line.

[0059] Figure 3 The hydraulic circuit diagram of the device 1 according to the invention for controlling partial volume flows 20', 20", 20'" as required is shown in a second embodiment, the device having a hydraulic unit 15 and a heat exchanger 14. Figure 2 , the oil pan 27 with the filter element 28, which is common to both directions of rotation of the motor-pump unit 21, is replaced by an oil pan 6, 12 with a filter element 28', 28" respectively arranged in front of the suction side. Thus, the transmission GBX, 10 is associated with the oil pan 12 and the electric drive machine 2 is associated with the oil pan 6, see Figure 1 .

[0060] Figure 4 The hydraulic circuit diagram of the device 1 according to the invention for controlling partial volume flows 20', 20", 20"' as required is shown in a third embodiment, the device having a hydraulic unit 15 and a heat exchanger 14. Figure 3In contrast to the second embodiment shown in , the directional control valve 31 and the hydraulically controllable switching valve 32 arranged downstream in the flow path are omitted. Instead, two further simple non-return valves 43, 44 are used in the hydraulic circuit diagram.

[0061] Figure 5 A method for distributing cooling oil / lubricating oil flows as required and controlling the cooling oil start flow temperature of partial volume flows in an electric traction drive having a device according to the invention according to one of the preceding figures is shown by way of example. In this case, a request for active pump operation of the pump is queried, wherein the active pump operation can be an operating type in a first rotational direction A or in a second rotational direction B.

[0062] In the flowchart, it is first queried whether the vehicle is in motion. If the question is positive, a check of the winding head limit temperature is performed.

[0063] If the winding head limiting temperature has not been reached, the query is terminated and no pump operation is required.

[0064] However, if the winding head limiting temperature is reached or exceeded in the question, a query is made as to whether the rotor shaft limiting temperature of the electric machine is reached. If this is not the case, a query is made as to whether the transmission limiting temperature is reached. If this is not the case, a pump operation is started in the rotational direction A at pressure level 1 to achieve the first operating mode. If both limiting temperatures (of the winding head and the rotor shaft) are reached or exceeded, a query is made as to whether the transmission limiting temperature is reached. If the transmission limiting temperature is reached or exceeded, a pump operation is started in the rotational direction A at pressure level 2 to achieve the second operating mode.

[0065] However, if it is determined in the query step that the transmission limiting temperature has not yet been reached, but the winding head limiting temperature and the rotor shaft limiting temperature have been reached as described above, pump operation is started in the direction of rotation B at pressure level 1 to achieve the third operating mode.

[0066] If it is determined in the first query of the flowchart shown that the vehicle is not in motion, a query is made between active cooling or heating settings. If "cooling" is requested in the query, the heat exchanger is activated to implement the "cooling" setting. In addition, a pump operation is started in the direction of rotation A at a pressure level 1 to implement the first operating mode.

[0067] As long as cooling is not required, the “heating” setting is queried. If heating is required, the winding head is energized and the pump operation is started in the direction of rotation A at a pressure level 1 in order to implement the first operating mode.

[0068] The third operating mode describes an optimized efficiency mode in which hot oil is present in the transmission and cold oil is present for the stator windings of the electric machine and no oil is pumped into the rotor shaft of the electric machine, thereby eliminating splash losses in the rotor shaft.

[0069] By increasing the temperature level in the transmission with hot oil, the oil viscosity is reduced, thereby reducing splash losses and meshing losses.

[0070] For example, it was possible to measure that the energy required for operation of the traction drive decreases by approximately 9 Wh when the temperature in the transmission increases by 10° C.

[0071] In the second operating mode, the oil flow in the transmission, in the rotor / stator and at the stator winding heads is cooled, thereby achieving the maximum possible power of the electric traction drive. In this operating mode, maximum speed and uniform energy levels can be achieved.

[0072] In the first operating mode, only the stator winding heads are cooled, otherwise the transmission is allowed to generate splash losses and rotor cooling is omitted. Moderate driving is possible, in particular starting of the vehicle.

[0073] In this case, the parameters used for the above-described regulation and switching between the operating modes are the oil temperature, the pump power, the power and / or the rotational speed of the electric machine.

[0074] Figure 6 , Figure 7 and Figure 8 Shows that it can be used in Figure 3 The operating mode implemented by the device shown in FIG.

[0075] exist Figure 6 In the illustrated first operating mode, the volume flow 40 of the cooling lubricant (oil) from the oil sump 12 is indicated by a dashed line. It can be seen that in the first operating mode only a partial volume flow 20'' is provided to the stator 5, whereby active stator cooling takes place.

[0076] In the first operating mode, the pump 18 of the motor-pump unit 21 is operated at a pump speed in a clockwise direction at a first pressure level (low pressure level), whereby cooling lubricant is sucked from the oil sump 12 and conveyed via the 3 / 2-way valve and the reversing valve in the first position and the flow line 34 through the heat exchanger 14 and then directly to the stator. Due to the low pressure level in the flow line, the hydraulically controllable shut-off valve 36 remains in the shut-off position. Therefore, the rotor is not cooled.

[0077] Cooling and lubrication in the transmission GBX, 10 is realized passively. In this case, oil is supplied as cooling lubricant from the gears of the transmission by splashing into a storage container and then distributed via channels in the transmission.

[0078] exist Figure 7 In the second operating mode shown, the volume flow 41 of the cooling lubricant (oil) from the oil sump is shown as a dashed line. It can be seen that in the second operating mode, all partial volume flows 20 ′, 20 ″, 20 ′″ are provided to the transmission GBX, 10, the rotor 3 and the stator 5, whereby the temperature-critical active components, namely the stator 5 and the rotor 3, are actively cooled. In addition, the lubrication and cooling of the transmission 10 is also actively realized.

[0079] In the second operating mode, the pump 18 of the motor-pump unit 21 is operated at a pump speed in a clockwise direction at a second pressure level (high pressure level), whereby the cooling lubricant (oil) is sucked from the oil sump 12 and conveyed through the heat exchanger 14 via the 3 / 2-way valve 32 and the reversing valve 31 in the first position and the flow line 34. After the heat exchanger 14, the volume flow 41 is divided into three partial volume flows 20', 20", 20'". Due to the high pressure level in the flow line, the hydraulically controllable shut-off valve 36 is released and a portion of the volume flow is conveyed to the rotor via the throttle plate 38a and a portion of the volume flow is conveyed to the transmission 10 via the fluid line 22 and the non-return valve 23 and the throttle plate 38b. All partial volume flows have the same starting flow temperature in the second operating mode.

[0080] exist Figure 8 In the third operating mode shown, the volume flow 42 of the cooling lubricant (oil) from the oil sump is shown as a dashed line. It can be seen that in the third operating mode, partial volume flows 20 ′ and 20 ″′ are provided to the transmission GBX, 10 and the stator 5. The partial volume flows 20 ′ and 20 ″′ have different initial flow temperatures because the partial volume flow 20 ′ is not guided through the heat exchanger 14 for cooling.

[0081] Oil is actively fed into the gear mechanism 10 for lubrication, but it does not flow through the heat exchanger 14 beforehand. The cooling of the stator 5 is active, the rotor 3 is not cooled.

[0082] In the third operating mode, the pump 18 of the motor-pump unit 21 is operated at a pump speed in a counterclockwise direction at a first pressure level (low pressure level), whereby the cooling lubricant (oil) is sucked from the oil pan 6. Figure 2 As shown, oil can also be sucked from a connected oil sump 27 .

[0083] The oil is then guided via the reversing valve 31 in the second position and the 3 / 2-way valve 32 in the second position. When the pump is operated counterclockwise at the pump speed, the 3 / 2-way valve is adjusted into the second position via the control line 33 and the prevailing pressure. In the second position of the 3 / 2-way valve 32, the volume flow 42 is divided into a portion which is guided via the flow line 34 through the heat exchanger 14 and then directly to the stator 5. Due to the low pressure level in the flow line, the hydraulically controllable shut-off valve 36 remains in the shut-off position. The rotor 3 is therefore not cooled.

[0084] A second portion of the volume flow 42 is conveyed via a 3 / 2-way valve directly into the fluid line 16 as partial volume flow 20' into the transmission 10. This portion of the volume flow does not flow through the heat exchanger 14, is not cooled, and therefore has a higher starting flow temperature.

[0085] Fig. 9 , Fig.10 and Fig.11 Shows that it can be used in Figure 4 The operating mode implemented by the device shown in FIG.

[0086] In the device and the corresponding method, the cooling lubricant can either also be conducted through a heat exchanger or it can be fed directly into the transmission 10 or to temperature-critical active components of the electric machine 2. In contrast to the previously described device and the method according to the first and second embodiments, the three different operating modes are realized by simple nonreturn valves 43, 44 and a spring-loaded nonreturn valve 36. The switching valve 31 and the 3 / 2-way valve 32 are omitted.

[0087] exist Fig. 9 In the illustrated first operating mode, the volume flow 40 of the cooling lubricant (oil) from the oil sump is indicated by a dashed line. It can be seen that in the first operating mode only a partial volume flow 20'' is supplied to the stator 5, whereby active stator cooling takes place.

[0088] In the first operating mode, the pump 18 of the motor-pump unit 21 is operated at a pump speed in a clockwise direction at a first pressure level (low pressure level), whereby cooling lubricant is sucked from the oil sump and conveyed via the flow line 34 through the heat exchanger 14 and then directly to the stator. Due to the low pressure level in the flow line, the hydraulically controllable shut-off valve 36 remains in the shut-off position. Therefore, the rotor is not cooled.

[0089] The flow line 48 , which is the connection between the flow line 34 and the fluid line 16 , is blocked from flowing into the transmission via the nonreturn valve 44 .

[0090] Cooling and lubrication in the transmission GBX, 10 is realized passively. In this case, oil as cooling lubricant is conveyed from the gears of the transmission by splashing into a storage container and then distributed via channels in the transmission.

[0091] exist Fig.10 In the second operating mode shown, the volume flow 41 of the cooling lubricant (oil) from the oil sump 12 is shown as a dashed line. It can be seen that in the second operating mode, all partial volume flows 20 ′, 20 ″, 20 ′″ are provided to the transmission GBX, 10, the rotor 3 and the stator 5, whereby the temperature-critical active components stator and rotor are actively cooled. In addition, lubrication and cooling of the transmission are also actively achieved.

[0092] In the second operating mode, the pump 18 of the motor-pump unit 21 is operated at a pump speed in a clockwise direction at a second pressure level (high pressure level), whereby the cooling lubricant (oil) is sucked from the oil sump 12 and conducted through the heat exchanger 14 via the flow line 34. After the heat exchanger 14, the volume flow 41 is divided into three partial volume flows 20', 20", 20'". Due to the high pressure level in the flow line, the hydraulically controllable shut-off valve 36 is released and a portion of the volume flow is delivered to the stator via the throttle plate 38a and a portion of the volume flow is delivered to the transmission via the non-return valve and the throttle plate DB2. In the second operating mode, all partial volume flows have the same starting flow temperature, which is required for cooling the components.

[0093] exist Fig.11 In the third operating mode shown, the volume flow 42 of the cooling lubricant (oil) from the oil sump 6 is shown as a dashed line. It can be seen that in the third operating mode, partial volume flows 20 ′ and 20 ″′ are provided to the transmission GBX, 10 and the stator 5. The partial volume flows 20 ′ and 20 ″′ have different initial flow temperatures because the partial volume flow 20 ′ is not conducted through the heat exchanger 14 for cooling.

[0094] Oil is actively fed into the gear mechanism 10 for lubrication, but it does not previously flow through the heat exchanger 14. The cooling of the stator 5 is active, the rotor 3 is not cooled.

[0095] In the third operating mode, the pump 18 of the motor-pump unit 21 is operated at a pump speed in a counterclockwise direction at a first pressure level (low pressure level), whereby the cooling lubricant (oil) is sucked from the oil pan 6. Figure 2 As shown, oil can also be sucked from a connected oil sump 27 .

[0096] The volume flow 42 is then divided. A first portion is conducted via the flow line 48 and the nonreturn valve 44 into the flow line 34 and then through the heat exchanger 14 and then directly to the stator 5. Due to the low pressure level in the flow line, the hydraulically controllable shut-off valve 36 remains in the shut-off position. Therefore, the rotor 3 is not cooled.

[0097] A second portion of the volume flow 42 is fed directly into the fluid line 16 and into the transmission 10. This portion of the volume flow does not flow through the heat exchanger 14, is not cooled, and therefore has a higher starting flow temperature.

[0098] Reference numerals list

[0099] 1 Device

[0100] 2 Electric drive machines

[0101] 3 Rotor

[0102] 4 Rotor shaft

[0103] 5. Stator

[0104] 6 Oil sump

[0105] 8Intermediate shaft

[0106] 10GBX, transmission

[0107] 11 Driven shaft

[0108] 12 Oil sump

[0109] 14Heat exchanger

[0110] 14a Inflow pipe

[0111] 14b Outflow line

[0112] 15 Hydraulic unit

[0113] 16 Fluid pipeline

[0114] 17 Fluid pipeline

[0115] 18 Cooling lubricant pump

[0116] 19 Electric Motor

[0117] 20'First part volume flow

[0118] 20" Second part volume flow

[0119] 20"' Third part volume flow

[0120] 21 Motor-Pump Unit

[0121] 22 Fluid pipeline

[0122] 23 Check valve

[0123] 24 Flow lines

[0124] 26' Check Valve

[0125] 26" Check Valve

[0126] 27 Oil sump

[0127] 28 filter elements

[0128] 31 Directional valve

[0129] 32 Hydraulically controlled switching valve

[0130] 33 Control pipeline

[0131] 34 Fluid pipeline

[0132] 36 stop valve

[0133] 37 Bypass line

[0134] 38a Throttle plate

[0135] 39 Check valve

[0136] 38b throttle plate

[0137] 40 volume flow

[0138] 41 Volume flow

[0139] 42 Volume flow

[0140] 43 Check valve

[0141] 44 Check valve

[0142] 48 Flow lines

[0143] WH stator winding head

Claims

1. A device (1) for controlling the starting flow temperature of a cooling oil flow / lubricating oil flow in an electric traction drive as required, the device comprising an electrically controllable motor-pump unit (21) and a hydraulic unit (15), wherein the motor-pump unit (21) can be controlled in two rotational directions, namely in a first rotational direction and in a second rotational direction opposite to the first rotational direction, and wherein a first pressure level and a second pressure level higher than the first pressure level can be set at the motor-pump unit (21) via speed regulation in the first rotational direction or in the second rotational direction, respectively, and wherein the motor-pump unit (21) is connected to the hydraulic unit (15) via a controllable motor-pump unit (21) for controlling the starting flow temperature of a cooling oil flow / lubricating oil flow. A plurality of fluid outlets of first, second and third partial volume flows (20', 20", 20"') are connected, the fluid outlets being connected at least to a stator (5) of an electric drive machine (2) and / or a rotor (3) of the electric drive machine (2) and / or the transmission (10) for cooling and / or heating and / or lubrication, wherein the device (1) comprises a heat exchanger (14), and wherein the first partial volume flow (20') is not connected to the heat exchanger (14), and wherein the direction of rotation and the pressure level of the motor-pump unit (21) can be set via an electric control unit, and three different operating modes are set depending on the direction of rotation and the pressure level, characterized in that The first partial volume flow (20') is associated with the inflow of the transmission (10), the second partial volume flow (20") is associated with the inflow of the rotor (3), and the third partial volume flow (20'") is associated with the inflow of the stator (5), and the hydraulic unit (15) has a reversing valve (31) connected downstream of the flow path of the motor-pump unit (21) and a subsequent hydraulically controllable valve, preferably a 3 / 2-way valve, wherein the 3 / 2-way valve can be adjusted from a first position to a second position via a control line and a control pressure, and And in the first position of the 3 / 2-way valve (32), the volume flow from the motor-pump unit (21) is connected to the heat exchanger (14) via a fluid line (34), and the output end of the heat exchanger (14) is implemented as a fluid line (17), which branches into the second and third partial volume flows (20", 20"'), wherein the third partial volume flow (20"') flows directly as inflow to the stator (5), and wherein the second partial volume flow is guided to the rotor (3) via a hydraulically controllable non-return valve (36).

2. The device (1) according to claim 1, characterized in that The first partial volume flow (20') is formed by means of a fluid line (16), in which a non-return valve (39) and a throttle plate (38b) are arranged.

3. The device (1) according to claim 1, characterized in that In a first operating mode, the pump speed of the motor-pump unit (21) is operated clockwise in the first direction of rotation at a low pressure level, and the entire volume flow (40) flows through the 3 / 2-way valve and the reversing valve (31) in the first position, the fluid line (24) and the heat exchanger (14) for cooling and lubricating the stator (5) as a third partial volume flow (20'"), and the inflow to the rotor (3) and the transmission (10) is blocked.

4. The device according to claim 1, characterized in that In a second operating mode, the pump speed of the motor-pump unit (21) is operated in the first rotational direction in a clockwise direction at a high pressure level, and the volume flow (41) is directed to the heat exchanger (14) via the 3 / 2-way valve in the first position for active cooling of the transmission (10), the rotor (3) and the stator (5), and is divided into the first, second and third partial volume flows (20, 20", 20"') after the heat exchanger (14), wherein the check valve (36) is in a released position due to the high pressure level, and the volume flow is divided into the first partial volume flow and the second partial volume flow after the check valve (36) via a fluid line.

5. The device according to claim 1, characterized in that In a third operating mode, the pump speed of the motor-pump unit (21) is operated counterclockwise in the second rotational direction at a low pressure level, and the entire volume flow (42) flows through the 3 / 2-way valve and the reversing valve (31) in the second position and is divided into a first portion, which flows through the fluid line (34) and the heat exchanger (14) to cool and lubricate the stator (5) as a third partial volume flow (20'"), wherein the inflow to the rotor (3) is blocked and the second portion is delivered from the 3 / 2-way valve (32) directly via the fluid line (16) as a first partial volume flow (20) with a high initial flow temperature to the transmission (10) for lubrication.

6. A method for distributing and setting the starting flow temperature of a cooling oil flow / lubricating oil flow in an electric traction drive according to requirements by means of a device (1) according to claim 1, characterized in that Three different operating modes can be set depending on the operation of the motor-pump unit (21) in a first rotational direction or in an opposite second rotational direction and the setting of the pressure level, wherein a first and / or second and / or third partial volume flow (20', 20", 20'") with the same or different initial flow temperature can be set depending on the operating mode. 7 . The method according to claim 6 , wherein the three operating modes are an efficiency mode with optimized energy management, a maximum power mode and a mild driving mode with reduced cooling of only the windings of the stator. 8 . The method according to claim 7 , wherein the switching between the operating modes is performed based on the following parameters: oil temperature, pump power, power and rotational speed of the electric motor.

9. The method according to claim 6, characterized in that In a first operating mode, the motor-pump unit (21) is operated at a pump speed clockwise in the first rotational direction at a low pressure level, whereby active cooling of the stator (5) is achieved exclusively via the third partial volume flow (20'').

10. The method according to claim 6, characterized in that In a second operating mode, the pump speed of the motor-pump unit (21) is operated in the first rotational direction clockwise at a high pressure level, thereby achieving active cooling of the transmission (10), the rotor (3) and the stator (2) via the first, second and third partial volume flows (20', 20", 20'") having the same initial flow temperature.

11. The method according to claim 6, characterized in that In a third operating mode, the pump speed of the motor-pump unit (21) is operated counterclockwise in the second rotational direction at a low pressure level, thereby achieving active cooling of the stator (5) via the third partial volume flow (20'") with a low initial flow temperature and lubrication of the transmission (10) via the first partial volume flow (20') with a higher initial flow temperature.

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