Supply system for a device having an electric machine, and electrically drivable vehicle axle

Abstract

The invention relates to a supply system (13) for a device having an electric machine, in particular for an electrically drivable vehicle axle, comprising a stator supply line (17) and a rotor supply line (29), wherein the stator supply line (17) is connected to a stator cooling circuit (21) for a stator (7) of the electric machine (6), whereas the rotor supply line (29) is connected to a rotor cooling circuit (34) for a rotor (8) of the electric machine (6). The stator supply line (17) is additionally connected to the pressure side of a feed pump (14), via which the stator supply line (17) can be supplied with a lubricant and / or coolant. Furthermore, the rotor supply line (29) is connected to an outlet (26) of the stator cooling circuit (21).

Description

[0001] ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12

[0002] Supply system for a device comprising an electric machine and electrically driven vehicle axle

[0003] The invention relates to a supply system for a device comprising an electric machine, in particular for an electrically driven vehicle axle, comprising a stator supply line and a rotor supply line, wherein the stator supply line is connected to a stator cooling circuit for a stator of the electric machine, whereas the rotor supply line is connected to a rotor cooling circuit for a rotor of the electric machine, and wherein the stator supply line is also connected to a pressure side of a feed pump, via which the stator supply line can be supplied with a lubricant and / or coolant. The invention further relates to an electrically driven vehicle axle with the aforementioned supply system.

[0004] In electrically driven vehicle axles, in addition to the lubrication and cooling of mechanical components, cooling of the electric motor itself is also typically required. For this purpose, the electric motor of the respective vehicle axle is usually integrated into a supply system in which liquid lubricant and coolant, typically in the form of oil, can be supplied to the stator and rotor of the electric motor to provide cooling and thus enable efficient operation of the electric motor.

[0005] German patent DE 102023 200 684 A1 discloses a supply system for an electrically driven vehicle axle, wherein this supply system comprises a feed pump via which liquid lubricant and / or coolant can be drawn from a coolant reservoir and fed to a main supply line. The main supply line then branches into several lines, one of which is connected to a stator cooling circuit as a stator supply line, and one of which is connected to a rotor cooling circuit as a rotor supply line. Further lines are provided for supplying mechanical components. The lines, which are arranged as parallel branches, are each connected to a pressure side of the feed pump via the main supply line and can be supplied from the main supply line.Within the stator cooling circuit, the lubricant and / or coolant is supplied to the stator of the electric machine and then flows into the coolant reservoir, while within the rotor cooling circuit, a rotor of the electric machine is supplied. The lubricant and / or coolant then also flows from the rotor cooling circuit back into the coolant reservoir. In a variant of DE 10 2023 200 684 A1, valves are provided in both the stator supply line and the rotor supply line. These valves are designed as pressure-controlled poppet valves and allow the flow rate of lubricant and / or coolant supplied to the stator cooling circuit and the rotor cooling circuit, respectively, to be controlled.

[0006] Starting from the prior art described above, the object of the present invention is to create a supply system for a device comprising an electric machine, wherein this supply system should achieve the highest possible supply of a stator cooling circuit with a simple design.

[0007] This problem is solved starting from the preamble of claim 1 in conjunction with its characterizing features. The subsequent dependent claims each describe advantageous embodiments of the invention. An electrically driven vehicle axle comprising a supply system according to the invention is further the subject of claim 12.

[0008] According to the invention, a supply system for a device comprising an electric machine includes a stator supply line and a rotor supply line. The stator supply line is connected to a stator cooling circuit for one stator of the electric machine, while the rotor supply line is connected to a rotor cooling circuit for one rotor of the electric machine. The stator supply line is also connected to a pressure side of a feed pump, through which the stator supply line can be supplied with a lubricant and / or coolant. ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12

[0009] The supply system according to the invention is intended for use in a device comprising an electric machine, wherein this electric machine consists of a stator and a rotor. The supply system provides at least one supply of lubricant and / or coolant to the stator and rotor of the electric machine, preferably also supplying one or more mechanical components in addition to the stator and rotor. The supply system according to the invention is particularly preferred for use in an electrically driven vehicle axle, which is then equipped, in particular, with one or more further components requiring lubrication and / or cooling, in addition to the electric machine, wherein the further components are at least partially formed by mechanical components.

[0010] For supplying the rotor of the electric machine, a rotor cooling circuit is part of the supply system. Within this circuit, the rotor is cooled by the lubricant and / or coolant supplied to the circuit. This lubricant and / or coolant is supplied via a rotor supply line connected to the rotor cooling circuit. Specifically, the rotor supply line is connected to an inlet of the rotor cooling circuit and preferably represents the only connection to it. Within the rotor cooling circuit, in addition to supplying coolant to the rotor, coolant is preferably also supplied to a rotor bearing and, optionally, to a winding head of the electric machine, and in particular to a winding head cooling system.

[0011] In addition to the rotor cooling circuit, the supply system according to the invention also supplies a stator cooling circuit of the stator of the electric machine, wherein within the stator cooling circuit, in particular, in addition to a supply of lubricant and / or coolant to the stator of the electric machine, a supply of lubricant and / or coolant to a winding head of the electric machine and, preferably, at least one winding head shower is provided. For ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12

[0012] The stator cooling circuit is connected to a stator supply line for the supply of lubricant and / or coolant, with this stator supply line being connected, in particular, to an inlet of the stator cooling circuit. Preferably, the stator supply line is the only supply to the stator cooling circuit.

[0013] The supply system is also equipped with a feed pump that draws the lubricant and / or coolant from a reservoir, particularly on a suction side, and delivers it to a pressure side. The stator supply line is also connected to the pressure side of the feed pump, allowing the lubricant and / or coolant delivered by the feed pump to enter the stator supply line and thus the stator cooling circuit. Preferably, at least one filter and / or a heat exchanger is connected downstream of the feed pump, where the temperature of the lubricant and / or coolant can be reduced by heat exchange. A bypass can also be provided for the heat exchanger, in which a bypass valve is arranged. This bypass valve allows coolant to flow through the bypass, thus bypassing the heat exchanger, depending on the temperature of the lubricant and / or coolant, and in particular, in a stepless manner.The feed pump is in particular an electrically driven pump, which is preferably infinitely variable, so that the flow rate provided by the feed pump can also be infinitely varied.

[0014] The lubricant and / or coolant is, in particular, a liquid, meaning it is in liquid form. Preferably, this liquid is oil, which allows for both cooling and simultaneous lubrication.

[0015] For the purposes of the invention, a "conduit" is understood to be a guide for lubricant and / or coolant between the respective connection points. The respective conduit may be composed of several sections. Furthermore, the respective conduit may be formed entirely by a conduit pipe, entirely by a channel defined by an surrounding component, such as a housing, ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12, or partially by one or more conduits or channels.

[0016] The invention now comprises the technical teaching that the rotor supply line is connected to an outlet of the stator cooling circuit. In other words, the rotor supply line is connected not only to the rotor cooling circuit but also to an outlet and thus to an outlet side of the stator cooling circuit.

[0017] This design of a supply system has the advantage that the stator cooling circuit is connected in series with the rotor cooling circuit. According to the invention, the stator cooling circuit and the rotor cooling circuit are thus connected in series, with the stator cooling circuit being positioned upstream of the rotor cooling circuit from the perspective of the feed pump. This allows the stator cooling circuit to be supplied with a higher flow rate without requiring the feed pump to be designed for higher flow rates.Because the stator supply line is connected to the pressure side of the feed pump and the rotor supply line is connected to the outlet of the stator cooling circuit, the stator cooling circuit is supplied upstream, whereas the rotor cooling circuit is supplied downstream via the lubricant and / or coolant exiting at an outlet of the stator cooling circuit. This allows for high flow rates in the stator supply, and also improves the pressure supply to the winding head showers, as the pressure of the lubricant and / or coolant in the stator cooling circuit is increased. Furthermore, despite the downstream supply of the rotor cooling circuit, sufficient flow rates for supplying the rotor can be achieved. Overall, a simple design of the supply system according to the invention can be implemented while providing high flow rates to the stator cooling circuit.

[0018] Particularly preferred is the stator supply line within the supply system connected solely to the pressure side of the feed pump, so that the stator cooling circuit is supplied by the feed pump as the first element in the series, ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12 whereas the rotor cooling circuit and any other supply areas are connected downstream of the stator cooling circuit.

[0019] For the purposes of the invention, a "drain" of the stator cooling circuit is understood to be an interface within the supply system at which at least a portion of the volume flow supplied to the stator cooling circuit via the stator supply line reaches the stator cooling circuit after being supplied. Thus, the drain of the stator cooling circuit is preferably a drain side to which lubricant and / or coolant reaches after cooling the stator of the electric machine and after branching off partial volume flows directed to winding head showers.

[0020] According to one embodiment of the invention, at least one further line is connected to the outlet of the stator cooling circuit in parallel to the rotor supply line. This line serves to convey lubricant and / or coolant to a separate area from the rotor cooling circuit. In particular, the at least one further line is a return line connected to a reservoir or the suction side of the feed pump, and / or a supply line for at least one mechanical component. Therefore, in this case, the supply system according to the invention includes a return flow to a reservoir, to the suction side of a feed pump for the implementation of suction charging, and / or to mechanical components to supply these components for lubrication and / or cooling.

[0021] In a further development of the aforementioned embodiment, the rotor supply line is connected to the outlet of the stator cooling circuit via a throttle line, which allows a continuous supply of coolant and / or lubricant from the outlet of the stator cooling circuit into the rotor supply line. Furthermore, a valve assembly is arranged between the outlet of the stator cooling circuit on the one hand and the rotor supply line and the other line on the other. This valve assembly is biased into a closed position, in which it isolates the outlet of the stator cooling circuit from the other line and the rotor supply line. (See ZF Friedrichshafen AG File 304440, Friedrichshafen, September 12, 2024.)

[0022] The connection between the drain and the line and the rotor supply line is established based on the pressure of the lubricant and / or coolant prevailing in the process.

[0023] A design of the supply system according to the aforementioned variant has the advantage that a distribution to the rotor supply line, and thus to the rotor cooling circuit and the other line, can be achieved in a compact manner and with a simple design via the valve assembly located between the outlet of the stator cooling circuit, the rotor supply line, and the other line. This distribution is implemented depending on the pressure prevailing in the outlet, whereby the valve assembly, due to its preload, initially isolates the outlet of the stator cooling circuit from both the rotor supply line and the other line at a pressure level that does not induce a force on the valve assembly exceeding the preload.The supply to the rotor supply line and the additional line from the stator cooling circuit outlet is controlled by the valve assembly, depending on the pressure at the outlet. This valve assembly reliably allows for different pressure distributions between the rotor supply line and the additional line. The throttle line running between the stator cooling circuit outlet and the rotor supply line ensures a sufficient supply to the rotor supply line, and thus also to the rotor cooling circuit, to guarantee a basic supply to the rotor of the electric machine.

[0024] In the aforementioned embodiment of the invention, the valve assembly thus functions as a distribution device, whereby the valve assembly can assume different switching positions depending on the pressure, in particular in which the outlet is disconnected from the rotor supply line and from the further line, or in which one or more connections are established. Thus, in addition to the closed switching position, in which the outlet is disconnected from both the rotor supply line and the further line via the valve assembly, the valve assembly can assume other different switching positions.Each of these switching positions is assigned to a pressure level of the pressure prevailing at the outlet of the stator cooling circuit (ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12), whereby in each individual switching position a connection is established between the outlet and one of the two lines in the form of the rotor supply line and the other line, or simultaneous connections to both the rotor supply line and the other line are realized. According to the invention, the valve assembly can be formed by exactly one valve or by several valves.

[0025] Preferably, once a first pressure threshold is exceeded, the valve assembly connects the outlet of the stator cooling circuit to the other line. Furthermore, once a second pressure threshold, which is higher than the first, is exceeded, the valve assembly connects the outlet of the stator cooling circuit to the rotor supply line in addition to the connection to the other line. In this case, a connection between the outlet of the stator cooling circuit and the other line is established via the valve assembly once the first pressure threshold is exceeded. Then, once a second pressure threshold is exceeded, both the other line and the rotor supply line are connected to the outlet of the stator cooling circuit via the valve assembly.This allows for a suitable supply to the rotor supply line and the further line from the outlet of the stator cooling circuit.

[0026] Alternatively, but preferably in addition to the aforementioned embodiment, the valve assembly establishes the connections of the stator cooling circuit outlet to the line and the rotor supply line, each subject to pressure-dependent throttling. This results in a pressure-dependent change in the volume flow rate passing through the valve assembly at each connection point, as the valve assembly applies pressure-dependent throttling at the respective connection. The respective throttling can be indirectly proportional to the prevailing pressure, directly proportional to the prevailing pressure, or indirectly proportional to the prevailing pressure in at least one pressure range and directly proportional to the prevailing pressure in at least another pressure range. ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12

[0027] When combining the two aforementioned variants, the valve assembly, once the first pressure threshold is exceeded, connects the stator cooling circuit outlet to the further line with decreasing throttling as the pressure increases. Once the second pressure threshold is exceeded, the valve assembly then connects the stator cooling circuit outlet to the further line with essentially constant throttling and connects the inlet to the rotor supply line with decreasing throttling as the pressure increases. Furthermore, once a third pressure threshold, higher than the second, is exceeded, the valve assembly connects the stator cooling circuit outlet to the further line with increasing throttling as the pressure increases. This advantageously allows a suitable characteristic to be achieved in the supply system according to the invention.

[0028] In this case, from the moment the first pressure threshold is exceeded until the second pressure threshold is reached, the downstream line is initially supplied only from the outlet. As the pressure increases, the throttling of the connection between the outlet and the downstream line is progressively reduced, thus increasing the flow rate delivered to the downstream line. From the moment the second pressure threshold is exceeded until the third pressure threshold is reached, the connection between the outlet and the rotor supply line is also established. At this connection, the throttling is reduced with increasing pressure, thus increasing the flow rate supplied to the rotor supply line from the inlet with increasing pressure.Furthermore, the throttling of the connection between the outlet and the further line is now kept essentially constant. In the context of the invention, this means that the throttling changes only negligibly with respect to pressure, and the volume flow supplied to the further line is thus kept largely constant with respect to pressure. As the third pressure threshold is exceeded, the throttling of the connection between the outlet and the further line is then progressively increased with increasing pressure, and consequently, the volume flow conveyed from the outlet into the further line is progressively reduced. ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12.

[0029] When connecting the outlet to the rotor supply line, the throttling is preferably either kept constant or minimally reduced from the point at which the third pressure threshold is exceeded, in order to achieve a minimal increase in the volume flow delivered into the rotor supply line.

[0030] According to one embodiment of the invention, the valve assembly is formed by two pressure-controlled plate valves, one of which is arranged between the outlet side of the stator cooling circuit and the other line, and the other plate valve is arranged between the outlet side of the stator cooling circuit and the rotor supply line. This makes it possible to implement the valve assembly with low manufacturing costs.

[0031] According to an alternative embodiment of the invention, the valve is designed as a directional control valve in which a valve piston is slidably guided in a guide bore of a valve housing and pre-tensioned in a basic position corresponding to the closed position. The valve piston is subjected to the pressure prevailing at the stator cooling circuit outlet on one end face, contrary to the pre-tension, and establishes the connections of the stator cooling circuit outlet to the line and the rotor supply line depending on its pressure-dependent position. By designing the valve assembly as a directional control valve, the pressure-dependent establishment of the connections of the inlet to the further line and the rotor supply line can be easily implemented with a compact design.In particular, in combination with the variants described above, the different characteristics of the supply system according to the invention can also be reliably realized.

[0032] In a further development of the aforementioned design option, the stator cooling circuit outlet, the rotor supply line, and the additional line are connected to associated annular channels, which are integrated into the valve housing and each open into the guide bore. Spatial connections between the annular channels are established depending on the position of the valve piston. Preferably, the stator cooling circuit outlet is also connected via the throttle line to the annular channel to which the rotor supply line is connected. ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12

[0033] This allows the permanent connection of the stator cooling circuit outlet to the rotor supply line via the throttle line to be realized in a compact manner, by forming the throttle line between the outlet and the annular channel of the valve associated with the rotor supply line as a short section of pipe.

[0034] The invention further relates to an electrically driven vehicle axle which, in addition to a supply system according to one or more of the variants described above, comprises an electric machine. The stator cooling circuit of the supply system according to the invention is assigned to a stator of the electric machine, whereas the rotor cooling circuit of the supply system according to the invention is assigned to a rotor of the electric machine. Furthermore, one or more mechanical components of the electrically driven vehicle axle are preferably also supplied with the lubricant and / or coolant for lubrication and / or cooling within the supply system.

[0035] Advantageous embodiments of the invention, which are explained below, are illustrated in the drawings. They show:

[0036] Fig. 1 shows a schematic view of a motor vehicle with an electrically driven axle according to a preferred embodiment of the invention;

[0037] Fig. 2 shows a schematic representation of a supply system for the vehicle axle from Fig. 1, corresponding to one embodiment of the invention;

[0038] Fig. 3 shows a schematic view of a supply system according to a further embodiment of the invention;

[0039] Fig. 4 shows a diagram of different volume flow rates of the

[0040] Supply system from Fig. 3; ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12

[0041] Figs. 5 to 8 Views of the supply system from Fig. 3 in the area of ​​a valve device, shown in different switching states;

[0042] Fig. 9 shows a schematic representation of a supply system according to a further embodiment of the invention; and

[0043] Fig. 10 shows a schematic view of a supply system according to a further embodiment of the invention.

[0044] Figure 1 shows a schematic view of a motor vehicle 1, in whose drivetrain 2 two drive axles 3 and 4 are provided. While drive axle 3 is designed as the steerable front axle of the motor vehicle 1, drive axle 4 is an unsteered rear axle. A drive motor 5 is assigned to drive axle 3, which can be an internal combustion engine or an electric motor and which can be, or is, coupled to the drive wheels of drive axle 3 via a transverse differential (not shown here).

[0045] The drive axle 4 is also equipped with a drive machine in the form of an electric machine 6, which consists of a stator 7 and a rotor 8. The rotor 8 is connected to a rotor shaft 9, which is coupled to an input side of a downstream transverse differential 10. The transverse differential 10 distributes the drive motion introduced into it to the drive wheels 11 and 12 of the drive axle 4 in a manner known to those skilled in the art.

[0046] The two drive axles 3 and 4 of the motor vehicle 1 are each designated as main driving axles in the motor vehicle drivetrain 1 and accordingly each permanently serve to drive the motor vehicle 1. However, within the scope of the invention, the motor vehicle 1 could also be equipped only with the drive axle 4 and a non-driven axle forming the front axle. ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12

[0047] For cooling the electric machine 6 and also for lubricating and cooling mechanical components of the drive shaft 4, the drive shaft 4 is equipped with a supply system 13, which is shown schematically in Fig. 2 and is designed according to one embodiment of the invention. This supply system 13 comprises a controllable feed pump 14, via which liquid lubricant and coolant in the form of oil can be drawn from a suction area 15 through a suction-side suction filter 16 and conveyed into a stator supply line 17.

[0048] The feed pump 14 is specifically an electric pump and can continuously adjust the current flow rate of lubricant and coolant. A heat exchanger 18 and a pressure filter 19 are also provided downstream of the stator supply line 17 and the feed pump 14. The lubricant and coolant pumped into the stator supply line 17 can be cooled by heat exchange with the environment via the heat exchanger 18. According to the invention, a supply line to a hydraulic parking lock of the drive axle 4 can also branch off between the feed pump 14 and the heat exchanger 18.

[0049] The stator supply line 17 connects the pressure side of the feed pump 14, downstream of the pressure filter 19, to an inlet 20 of a stator cooling circuit 21. Within this circuit, a stator cooling unit 22, for cooling the stator 7 of the electric machine 6, and two winding head showers 23 and 24 are supplied with the lubricant and coolant provided via the stator supply line 17. A connection to the winding head shower 23 branches off on the inlet side of the stator cooling unit 22, while a connection to the winding head shower 24 branches off on the outlet side of the stator cooling unit 22. Following delivery to the respective winding head shower 23 or 24, the lubricant and coolant then flow back into a reservoir 25, from which the lubricant and coolant can be drawn again via the intake area 15 by the feed pump 14.

[0050] A drain line 27 is connected to a drain 26 of the stator cooling circuit 21, from which an inlet line 28 initially branches off, with the drain line 27 in ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12

[0051] The connection then branches into a rotor supply line 29 and a return line 30. The supply line 28 leads to a mechanical supply circuit 31, in which mechanical components 32 and 33 of the drive axle 4 are supplied for lubrication and / or cooling. These mechanical components may include bearings, gears of the transverse differential 10, etc. After supplying the mechanical components 32 and 33, the lubricant and coolant are then returned to the reservoir 25.

[0052] A connection to a rotor cooling circuit 34 is established via the rotor supply line 29. Within this circuit, lubricant and coolant are supplied to the rotor cooling system 35 and the bearings 36 of the rotor 8 for lubrication and cooling. Following a rotary feedthrough 37, which acts as a throttle, the supply is divided between the rotor cooling system 35 and the bearings 36. After supplying the rotor cooling system 35 and the bearings 36, the supply is then returned to the reservoir 25.

[0053] A throttle point 38 is provided in the return line 30, which also connects to the reservoir 25. Due to the arrangement of the stator cooling circuit 21, the mechanical supply circuit 31, the rotor cooling circuit 34, and the return to the reservoir 25 via the discharge line 30, the stator cooling circuit 21 is initially connected in series with the feed pump 14, thus providing the stator cooling circuit 21 with a high volume flow of lubricant and coolant. Only after this supply to the stator cooling circuit 21 does further distribution to the rotor cooling circuit 34 and the mechanical supply circuit 31, as well as return to the reservoir 25, occur.

[0054] Figure 3 shows a schematic representation of a supply system 39 according to a further embodiment of the invention. This supply system 39 largely corresponds to the supply system 13 from Figure 2 and can be used as an alternative to the latter for the drive shaft 4. In contrast to the supply system 13 from Figure 2, a valve assembly 41 is placed between the drain line 27 on the one hand and the rotor supply line 29 and a return line 40 on the other. This valve assembly distributes the lubricant and coolant to the return line 40 and the rotor supply line 29 depending on the pressure of the lubricant and coolant prevailing in the drain line 27.The valve assembly 41 is designed as a directional control valve and comprises a valve piston 42, which is slidably guided in a guide bore 43 of a valve housing 44 and is biased into a home position by a spring element 45. On an end face of the valve piston 42 opposite the spring element 45, the valve housing 44 also forms a control chamber 46, which is connected to the drain line 27 via an orifice 47. As soon as the pressure prevailing in the drain line 27, and thus also in the control chamber 46, exerts an axial force on the valve piston 42 that exceeds the spring force acting by the spring element 45 in the direction of the home position, the valve piston 42 is moved from its home position, the positioning of the valve piston 42 in the valve housing 44 then depending on the pressure prevailing in the control chamber 46.

[0055] The valve housing 44 also forms several annular channels 48, 49, 50, and 51, each of which opens into the guide bore 43. Annular channel 48 is located adjacent to the control chamber 46, followed by annular channel 49, then annular channel 50, and finally annular channel 51. Annular channels 48 and 50 are each connected to the drain line 27, while the rotor supply line 29 is connected to annular channel 49 and the return line 40 to annular channel 51. The drain line 27 is also connected to the annular channel 49 via a throttle line 52, so that the drain line 27 and the rotor supply line 29 are permanently connected via the throttle line 52. This allows for a continuous flow of lubricant and coolant from the drain line 27 into the rotor supply line 29.Furthermore, the return line 40 leads to the suction side of the feed pump 14, whereby the amount of lubricant and coolant returned via the return line 40 can be used to charge the feed pump 14. Otherwise, the configuration shown in Fig. 3 corresponds to the variant shown in Fig. 2, so reference is made to the description therein. ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12.

[0056] Figure 4 shows the flow rates of different lubricant and coolant volume flows in the supply system 39 from Figure 3 plotted against a delivery volume flow Qp of the feed pump 14, where Qs is a volume flow supplied at the inlet 20 of the stator cooling circuit 21, QWDI is a volume flow supplied to the winding head shower 23, QWD2 is a volume flow supplied to the winding head shower 24, QG is a volume flow supplied to the mechanical supply circuit 31 via the inlet line 28, QRO is a volume flow supplied to the rotor cooling circuit 34 via the rotor supply line 29, and QR UA volume flow is returned via the return line 40. The volume flow Qs increases linearly with the delivery volume flow Qp, since the stator cooling circuit 21 is directly connected downstream of the feed pump 14 via the stator supply line 17 at its inlet 20. This ensures that the stator cooling circuit 21 receives the full delivery volume flow Qp and thus a high supply before further distribution occurs downstream to the mechanical supply circuit 31, the rotor cooling circuit 34, and the return line 40. As a result, the two volume flow rates QWDI and QWD2 also initially increase linearly before essentially constant profiles are achieved due to effective throttling.

[0057] The downstream distribution is influenced by the valve assembly 41 depending on the delivery volume flow rate Qp and thus also on the pressure of the lubricant and coolant acting in the drain line 27. Figures 5 to 8 show different switching states of the valve assembly 41 for different pressure levels acting in the drain line 27. Figure 5 shows the supply system 13 in a state in which the delivery volume flow rate Qp is below a first threshold I, and thus the pressure acting in the drain line 27 is also below a first pressure threshold. In this state, the valve piston 42 of the valve assembly 41 is moved to its home position by the spring element 45, in which the valve piston 42 separates the annular channels 48 and 50 from the annular channels 49 and 51. This completely prevents the flow of lubricant and coolant into the return line 40, thereby reducing the volume flow rate QR. UIn this area, the flow rate is zero, whereas the rotor supply line 29 is fed from the discharge line 27 solely via the throttle line 52. This also results in a linear increase in the volume flow rate QR0 and a basic supply to the rotor cooling circuit 34. Due to the closed state of the valve assembly 41 (ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12), the volume flow rate QG also increases significantly, thus ensuring a corresponding supply to the mechanical supply circuit 31.

[0058] Fig. 6 shows the supply system 39 in the area of ​​the valve assembly 41 in a state in which the delivery volume flow rate Qp in Fig. 4 has reached the first threshold I. As a result, the pressure acting in the discharge line 27 has also reached a pressure level at which the valve piston 42 is moved out of its home position against the spring element 45. When the delivery volume flow rate Qp exceeds the first threshold I, the valve piston 42, by further displacement within the valve housing 44, enables a spatial connection between the annular channels 50 and 51, so that lubricant and coolant can subsequently flow from the discharge line 27 into the return line 40. This is shown in Fig. 4 by a sharp increase in the volume flow rate QR occurring between the first threshold I and a second threshold II. Uas well as a stagnation in the increases of the volume flow QG and the volume flow QR0. As a result, a suction charging of the feed pump 14 is brought about.

[0059] In Fig. 7, the supply system 39 in the area of ​​the valve assembly 41 is shown in a further state in which the delivery volume flow Qp in Fig. 4 lies at the second threshold II. Subsequently, a further pressure level is reached by the pressure acting in the discharge line 27, at which the valve piston 42 in the valve housing 44 assumes the position shown in Fig. 7. As soon as the second threshold II is subsequently exceeded by the delivery volume flow Qp, a spatial connection is established between the annular channels 48 and 49 in the valve assembly 41, in addition to the spatial connection between the annular channels 50 and 51. This allows lubricant and coolant to flow from the discharge line 27 into the rotor supply line 29 in addition to the throttle line 52, resulting in a sharp increase in the volume flow QR0 in Fig. 7.4 between the second threshold II and a third threshold III results, thus increasing the supply to the rotor cooling circuit 34. At the same time, the increase in the volume flow QR stagnates. U between the second threshold II and the third threshold III. ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12

[0060] Finally, Fig. 8 shows a further representation of the supply system 39 in the area of ​​the valve assembly 41 in another state, whereby the delivery volume flow Qp in this state is at the third threshold III in Fig. 4. As a result, the pressure acting in the discharge line 27 has reached a pressure level at which the valve piston 42 is displaced against the spring element 45 in the valve housing 44 into the position shown in Fig. 8. In this position, the valve piston 42 throttles the flow of the lubricant and coolant from the annular channel 50 into the annular channel 51 and thus also the supply to the return line 40. In Fig. 4, this results in a drop in the volume flow QR from the third threshold III onwards. U above the delivery volume flow rate Qp, while the volume flow rate QR0 simultaneously increases sharply above the delivery volume flow rate Qp.

[0061] Furthermore, Fig. 9 shows a schematic view of a supply system 53 according to a further embodiment of the invention, wherein this supply system 53 can also be used as an alternative to the supply system 13 at the drive axle 4. The supply system 53 largely corresponds to the supply system 39 from Figs. 3 to 8, except that, in contrast to the supply system 39, the return line 40 now connects to the reservoir 25. In this respect, lubricant and coolant flowing via the return line 40 is not directed to the suction side of the feed pump 14, but is returned to the reservoir 25. Otherwise, the supply system 53 corresponds to the variant according to Figs. 3 to 8, so reference is made to the descriptions provided therein.

[0062] Finally, Fig. 10 shows a schematic representation of a supply system 54 according to a further embodiment of the invention. The supply system 54 largely corresponds to the supply system 53 from Fig. 9 and can be used as an alternative to the supply system 13 for the drive axle 4. The difference compared to the variant according to Fig. 9 is that in the supply system 54, a valve assembly 55 is now formed by two plate valves 56 and 57, which are each actuated depending on the pressure acting in the drain line 27. The plate valve 56 is arranged between the drain line 27 and the rotor supply line 29, while the ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12

[0063] A plate valve 57 is arranged between the drain line 27 and the return line 40. A throttle line 52 is also provided parallel to the plate valve 56. This design of the valve assembly 50 also allows for the distribution of lubricant and coolant from the drain line 27 to the rotor supply line 29 and the return line 40. Otherwise, the configuration according to Fig. 10 corresponds to the variant according to Fig. 9, so reference is made to the description therein.

[0064] Using the embodiments according to the invention, a supply system can be created in which, with a simple design, the highest possible supply of a stator cooling circuit for a stator of the electric machine is achieved.

[0065] ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12

[0066] Reference sign

[0067] 1 motor vehicle

[0068] 2. Motor vehicle powertrain

[0069] 3 drive axle

[0070] 4 drive axle

[0071] 5 Drive machine

[0072] 6 electric machine

[0073] 7 Stator

[0074] 8 Rotor

[0075] 9 Rotor shaft

[0076] 10 Transverse differential

[0077] 11 Drive wheel

[0078] 12 drive wheel

[0079] 13 Supply system

[0080] 14. Pump

[0081] 15 Intake area

[0082] 16 suction filters

[0083] 17 Stator supply line

[0084] 18 heat exchangers

[0085] 19 pressure filters

[0086] 20 inflows

[0087] 21 Stator cooling circuit

[0088] 22 Stator cooling

[0089] 23 Changing head shower

[0090] 24 changing head shower

[0091] 25 Reservoir

[0092] 26 Procedure

[0093] 27 Drain line

[0094] 28 Inlet pipe

[0095] 29 Rotor supply line

[0096] 30 Return line

[0097] 31 Mechanical Supply Circle ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12

[0098] 32 components

[0099] 33 Components

[0100] 34 Rotor cooling circuit

[0101] 35 Rotor cooling

[0102] 36 warehouses

[0103] 37 Rotary feedthrough

[0104] 38 Throttle point

[0105] 39 Supply system

[0106] 40 Return line

[0107] 41 Valve assembly

[0108] 42 valve pistons

[0109] 43 Guide hole

[0110] 44 Valve housings

[0111] 45 spring element

[0112] 46 Tax Chamber

[0113] 47 aperture

[0114] 48 Ring channel

[0115] 49 Ring channel

[0116] 50 ring channel

[0117] 51 Ring channel

[0118] 52 Throttle line

[0119] 53 Supply system

[0120] 54 Supply system

[0121] 55 Valve assembly

[0122] 56 plate valve

[0123] 57 plate valve

[0124] Qp flow rate

[0125] Qs volume flow rate stator cooling circuit

[0126] QWDI volume flow rolling head shower

[0127] QWD2 Volume flow rolling head shower

[0128] QG Volume flow mechanical supply circuit

[0129] QRO Volume Flow Rotor Cooling Circuit ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12

[0130] QRU Volume flow return

[0131] I first threshold

[0132] II second threshold

[0133] III third threshold

Claims

ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12 Patent claims 1. Supply system (13; 39; 53; 54) for a device comprising an electric machine (6), in particular for an electrically driven vehicle axle (4), comprising a stator supply line (17) and a rotor supply line (29), wherein the stator supply line (17) is connected to a stator cooling circuit (21) for a stator (7) of the electric machine (6), whereas the rotor supply line (29) is connected to a rotor cooling circuit (34) for a rotor (8) of the electric machine (6), and wherein the stator supply line (17) is also connected to a pressure side of a feed pump (14), via which the stator supply line (17) can be supplied with a lubricant and / or coolant, characterized in that the rotor supply line (29) is connected to a drain (26) of the stator cooling circuit (21).

2. Supply system (13; 39; 53; 54) according to claim 1 , characterized in that at least one further line is connected to the outlet (26) of the stator cooling circuit (21 ) in parallel to the rotor supply line (29), which each serves to guide lubricant and / or coolant to an area separate from the rotor cooling circuit (34).

3. Supply system (13; 39; 53; 54) according to claim 2, characterized in that the at least one further line is a return line (30; 40) which is connected to a reservoir (25) or a suction side of the feed pump (14), and / or a supply line (28) for supplying at least one mechanical component (32, 33).

4. Supply system (39; 53; 54) according to claim 2 or 3, characterized in that the rotor supply line (29) is connected to the outlet (26) of the stator cooling circuit (21) via a throttle line (52) which allows a permanent supply of coolant and / or lubricant from the outlet (26) of the stator cooling circuit (21) into the rotor supply line (29), wherein a valve assembly (41; 55) is arranged between the outlet (26) of the stator cooling circuit (21) on the one hand and the rotor supply line (29) and the further line on the other hand, which is biased into a closed switching position in which the valve assembly (41; 55) ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12 The outlet (26) of the stator cooling circuit (21) separates from the further line and the rotor supply line (29), and establishes connections of the outlet (26) to the further line and the rotor supply line (29) depending on a pressure of the lubricant and / or coolant prevailing in the outlet (26).

5. Supply system (39; 53; 54) according to claim 4, characterized in that the valve device (41; 55) connects the outlet (26) of the stator cooling circuit (21) to the further line when a first pressure threshold is exceeded, wherein the valve device (41; 55) connects the outlet (26) of the stator cooling circuit (21) to the rotor supply line (29) in addition to the connection to the further line when a second pressure threshold, which is above the first pressure threshold, is exceeded.

6. Supply system (39; 53; 54) according to claim 4 or 5, characterized in that the valve device (41; 55) establishes the connections of the outlet (26) of the stator cooling circuit (21) to the further line and the rotor supply line (29) each under a pressure-dependent throttling.

7. Supply system (39; 53; 54) according to claim 5 and claim 6, characterized in that the valve assembly (41; 55) establishes the connection of the outlet (26) of the stator cooling circuit (21) with the further line with decreasing throttling as the pressure increases, from the point at which the first pressure threshold is exceeded, wherein the valve assembly (41; 55) establishes the connection of the outlet (26) of the stator cooling circuit (21) with the further line with substantially constant throttling from the point at which the second pressure threshold is exceeded, and the connection of the outlet (26) of the stator cooling circuit (21) with the rotor supply line (29) with decreasing throttling as the pressure increases, and wherein the valve assembly (41; 55) establishes the connection of the outlet (26) of the stator cooling circuit (21) with the further line with decreasing throttling as the pressure increases, from the point at which a third pressure threshold, which is higher than the second pressure threshold, is exceeded, by the pressure creates throttling. ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12 8. Supply system (54) according to one of claims 4 to 7, characterized in that the valve assembly (55) is formed by two pressure-controlled plate valves (56, 57), one of which is a plate valve (57) located between the outlet (26) of the stator cooling circuit (21) and the further line, and the other plate valve (56) located between the outlet (26) of the stator cooling circuit (21) and the rotor supply line (29).

9. Supply system (39; 53) according to one of claims 4 to 7, characterized in that the valve device (41 ) is designed as a directional control valve in which a valve piston (42) is slidably guided in a guide bore (43) of a valve housing (44) and is biased into a basic position associated with the closed switching position, wherein the valve piston (42) is subjected at one end face against the bias with the pressure prevailing at the outlet (26) of the stator cooling circuit (21 ) and establishes the connections of the outlet (26) of the stator cooling circuit (21 ) to the line and the rotor supply line (29) depending on its pressure-dependent position.

10. Supply system (39; 53) according to claim 9, characterized in that the outlet (26) of the stator cooling circuit (21), the rotor supply line (29) and the further line are connected with associated annular channels (48, 49, 50, 51) which are formed in the valve housing (44) and each open into the guide bore (43), wherein spatial connections between the annular channels (48, 49, 50, 51) can be established depending on the position of the valve piston (42).

11. Supply system (39; 53) according to claim 10, characterized in that the outlet (26) of the stator cooling circuit (21 ) is also connected via the throttle line (52) to the annular channel (49) to which the rotor supply line (29) is connected.

12. Electrically driven vehicle axle (4), comprising an electric machine (6) and a supply system (13; 39; 53; 54) according to one or more of claims 1 to 11, wherein a stator (7) of the electric machine (6) is connected to the stator cooling circuit (21) of the supply system (13; 39; 53; 54) and a rotor (8) of the ZF Friedrichshafen AG File 304440 Friedrichshafen 2024-09-12 electrical machine (6) the rotor cooling rice (34) of the supply system (13; 39; 53; 54) is assigned.

Images