Electric drive unit for a motor vehicle, in particular for a motor car
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- MERCEDES BENZ GROUP AG
- Filing Date
- 2023-06-12
- Publication Date
- 2026-07-23
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
[0001] The invention relates to an electric drive device for a motor vehicle, in particular for a car. Furthermore, the invention relates to a method for operating such an electric drive device.
[0002] DE 10 2013 008 740 A1 discloses a hydraulic system for an automatic transmission.
[0003] The object of the present invention is to provide an electric drive device for a motor vehicle, in particular for a motor vehicle, and a method for operating such an electric drive device, so that a particularly advantageous fluid supply can be realized.
[0004] This object is achieved by an electric drive device having the features of patent claim 1 and by a method having the features of patent claim 10. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.
[0005] A first aspect of the invention relates to an electric drive device for a motor vehicle, also simply referred to as a vehicle and designed, for example, as a motor vehicle, in particular as a passenger car, which can be driven, in particular purely electrically, by means of the electric drive device. Thus, the motor vehicle is preferably an electric vehicle, in particular a battery-electric vehicle (BEV). The electric drive device has a coupling device which can be switched between a coupled state and a decoupling state. Furthermore, the electric drive device has a first electric machine, by means of which vehicle wheels, also referred to as drive wheels, of the motor vehicle can be driven, in particular purely electrically, by bypassing the coupling device. The motor vehicle can be driven by driving the vehicle wheels.
[0006] When reference is made to the vehicle wheels above and below, unless otherwise stated, this refers to the drive wheels. This means that the drive wheels can be driven by the first electric machine both in the coupled and uncoupled state of the coupling device.The feature that the vehicle wheels can be driven by means of the first electric machine bypassing the coupling device is to be understood as meaning that a respective torque that can be provided or is provided by the first electric machine and is intended to drive the vehicle wheels bypasses the coupling device on its way from the first electric machine to the respective vehicle wheel, i.e. does not flow or stream via the coupling device to the respective vehicle wheel, so that the first electric machine can drive the vehicle wheels both in the coupled state and in the uncoupled state of the coupling device.
[0007] For example, in its fully manufactured state, the motor vehicle has at least or exactly two vehicle axles, which are arranged consecutively and thus one behind the other in the longitudinal direction of the motor vehicle. Each vehicle axle has at least or exactly two vehicle wheels, which are also simply referred to as wheels, wherein the respective vehicle wheels of the respective vehicle axle are arranged, for example, on opposite sides of the motor vehicle in the transverse direction of the motor vehicle. Thus, the vehicle wheels of one of the vehicle axles are the aforementioned drive wheels. The vehicle wheels of the respective vehicle axle are ground contact elements, wherein the motor vehicle can be or is supported downwards on a ground in the vertical direction of the motor vehicle via the ground contact elements.If the motor vehicle is driven along the ground while the motor vehicle is supported downwards on the ground via the ground contact elements in the vertical direction of the motor vehicle, the ground contact elements roll, in particular directly, on the ground.
[0008] For example, the first electric machine has a first stator and a first rotor, which can be driven by the first stator and is thus rotatable about a first machine rotation axis relative to the first stator. In particular, the first electric machine can provide the respective drive torque, also referred to as the respective first drive torque, via its first rotor.
[0009] The electric drive device also has a second electric machine, which has, for example, a second rotor and a second stator.
[0010] For example, the second rotor can be driven by the second stator and thus rotated about a second machine rotation axis relative to the second stator. Preferably, the electric machines are arranged coaxially with each other so that the machine rotation axes coincide.
[0011] In the decoupling state of the coupling device, the second electrical machine, i.e. the second rotor, is decoupled from the vehicle wheels (drive wheels), so that in the decoupling state of the coupling device the second electrical machine cannot drive the vehicle wheels, and conversely the vehicle wheels cannot drive the second electrical machine, i.e. the second rotor, in the decoupling state, so that for example when in the decoupling state of the coupling device the vehicle wheels are driven exclusively by means of the first electrical machine, i.e. by means of the first rotor, with respect to the electrical machines, the first electrical machine or the vehicle wheels do not drag the second electrical machine or the second rotor, and therefore do not drive them.In the coupled state of the coupling device, the second electric machine, i.e., in particular, the second rotor, is coupled or can be coupled to the vehicle wheels, so that in the coupled state of the coupling device, the vehicle wheels can be driven via the coupling device by means of the second electric machine, i.e., the second rotor. This means that the second electric machine can provide a respective second drive torque, in particular via its second rotor. In the coupled state, the respective second drive torque can be transmitted to the vehicle wheels via the coupling device, thereby driving the vehicle wheels.Thus, if the coupling device is in its coupled state, the vehicle wheels can be driven, in particular simultaneously, by both the first electric motor and the second electric motor, thereby enabling, for example, a boost mode, also referred to as support mode. In the uncoupled state, the vehicle wheels can be driven exclusively by the first electric motor relative to the electric motors, thereby enabling particularly efficient, in particular energy-efficient, operation.
[0012] The electric drive device can have a differential gear, which can be designed, for example, as a planetary differential. For example, the vehicle wheels can be driven by the first electric machine via the differential gear, bypassing the coupling device. In the coupled state, for example, the vehicle wheels can be driven by the differential gear and by the second electric machine, i.e., by the second rotor, via the coupling device. In particular, in the uncoupled state, the differential gear can, for example, distribute, i.e., divide, the respective first drive torque provided or capable of being provided by the first electric machine via the first rotor, to the vehicle wheels.Thus, in the uncoupled state, the vehicle wheels can be driven, in particular simultaneously, via the differential gear by means of the first electric machine, that is to say by means of the first rotor, wherein, for example, the differential gear allows different speeds of the vehicle wheels, in particular when the motor vehicle is cornering, so that, for example, the vehicle wheel on the outside of the curve rotates or can rotate at a higher speed than the vehicle wheel on the inside of the curve.
[0013] The electric drive device has a high-pressure circuit through which a preferably liquid hydraulic medium, i.e., a fluid, flows, which is also simply referred to as a high-pressure circuit. For example, the hydraulic medium is a component of the electric drive device. The hydraulic medium is a fluid, or is also referred to as a fluid. The coupling device can be supplied with the hydraulic medium via the high-pressure circuit, so that the coupling device can be actuated by means of the hydraulic medium from the high-pressure circuit, i.e., by means of the hydraulic medium flowing through the high-pressure circuit, and thus switched from the uncoupled state to the coupled state.This means that the coupling device can be supplied with the hydraulic medium flowing through the high-pressure circuit via the high-pressure circuit, wherein the coupling device can be actuated by means of the hydraulic medium flowing through the high-pressure circuit, i.e. with the hydraulic medium from the high-pressure circuit, and can thus be switched from the uncoupling state to the coupling state.
[0014] The electric drive device also has a low-pressure circuit, which is also simply referred to as a low-pressure circuit and is, for example, at least partially fluidically separated from the high-pressure circuit. The hydraulic medium can flow through the low-pressure circuit as a cooling medium. This means that the hydraulic medium flowing through the low-pressure circuit is used as a cooling medium. Via the low-pressure circuit, at least one respective sub-area of the respective electric machine can be supplied with the hydraulic medium, thus with the cooling medium, for cooling at least the respective sub-area.This means that at least a first sub-region of the first electric machine can be supplied with the hydraulic medium flowing through the low-pressure circuit, i.e. with the hydraulic medium from the low-pressure circuit, via the low-pressure circuit, whereby the first sub-region of the first electric machine can be cooled by means of the hydraulic medium flowing through the low-pressure circuit, i.e. by means of the hydraulic medium from the low-pressure circuit. At least a second sub-region of the second electric machine can be supplied with the hydraulic medium flowing through the low-pressure circuit, i.e. with the hydraulic medium from the low-pressure circuit, via the low-pressure circuit, so that at least the second sub-region of the second electric machine can be cooled by means of the hydraulic medium flowing through the low-pressure circuit, i.e. by means of the hydraulic medium (cooling medium) from the low-pressure circuit.For example, the respective sub-area includes the respective stator and / or rotor of the respective electrical machine. For example, the hydraulic medium or cooling medium is oil.
[0015] The electric drive device has a first pump arranged in the high-pressure circuit, which is designed, for example, as a first electric pump, and thus as a first electrically operated pump. By means of the first pump, the hydraulic medium can be pumped through the high-pressure circuit, in particular at a first pressure. For example, the first pump can pump the hydraulic medium out of a reservoir that is common to the high-pressure circuit and the low-pressure circuit, in particular by sucking it in, and pumping it through the high-pressure circuit, in particular at the first pressure. This is to be understood in particular that during operation of the electric drive device, the hydraulic medium pumped through the high-pressure circuit by means of the first pump and thus flowing through the high-pressure circuit flows through the high-pressure circuit at the first pressure, and thus has the first pressure.The electric drive device also has a second pump arranged in the low-pressure circuit and provided in particular in addition to the first pump, which second pump is, for example, a second electric pump, and therefore a second electrically operated pump. By means of the second pump, the hydraulic medium can be pumped through the low-pressure circuit, in particular at a second pressure. For example, the second pump can pump the hydraulic medium out of the reservoir, in particular by sucking it in, and through the low-pressure circuit, in particular at the second pressure. This means that the hydraulic medium (cooling medium) pumped through the low-pressure circuit by means of the second pump and thus flowing through the low-pressure circuit has the second pressure, and therefore flows through the low-pressure circuit at the second pressure.In other words, for example, during the aforementioned operation of the electric drive device, the hydraulic medium is conveyed through the low-pressure circuit by means of the second pump, in particular at the second pressure, so that during operation the hydraulic medium flowing through the low-pressure circuit has the second pressure, thus flowing through the low-pressure circuit at the second pressure. The second pressure is lower than the first pressure. The first pressure is or can be effected or brought about, for example, by means of the first pump, and the second pressure is or can be effected or brought about, for example, by means of the second pump.
[0016] The electric drive device also has a connecting device, for example, having at least or exactly one connecting line or designed as a connecting line, by means of which, as will be explained in more detail below, the high-pressure circuit can be fluidly connected to the low-pressure circuit. The high-pressure circuit and the low-pressure circuit are also simply referred to as circuits, with a first of the circuits being the high-pressure circuit and a second of the circuits being the low-pressure circuit.
[0017] The electric drive device further comprises a valve device arranged in the connecting device, which valve device can be switched, in particular hydraulically, between a closed state fluidically blocking the connecting device and an open state fluidically releasing the connecting device. In the closed state, the connecting device is fluidically blocked by means of the valve device, so that in the closed state the circuits are not fluidly connected to one another via the connecting device. In the open state, the valve device releases the connecting device, so that in the open state the hydraulic medium can flow through the connecting device. Thus, in the open state, the high-pressure circuit is fluidly connected to the low-pressure circuit via the connecting device. In other words, the connecting device provides a fluidic connection between the circuits.In the closed state, the fluidic connection between the circuits is interrupted, i.e. blocked, by means of the valve device, so that in the closed state the circuits are not fluidically connected to one another via the connecting device. In the open state, the valve device releases the fluidic connection between the circuits. In other words, in the open state of the valve device, the fluidic connection between the circuits is established or released, so that in the open state the circuits are fluidly connected to one another via the connecting device and in particular via the valve device. The closed state is a first state of the valve device or is also referred to as the first state, wherein the open state is a second state of the valve device or is also referred to as the second state.
[0018] In order to be able to fluidically connect the circuits to one another as required via the connecting device, and thus to be able to interrupt, i.e. block or establish, the fluidic connection between the circuits as required, the electric drive device has an actuating device provided in addition to the connecting device, by means of which at least part of the hydraulic medium flowing through the high-pressure circuit can be branched off from the high-pressure circuit and guided to the valve device, which can be actuated by means of the hydraulic medium from the actuating device and can therefore be switched over at least from one of the states to the other state and preferably also from the other state to one state.In particular, for example, the valve device can be switched from the closed state to the open state and / or from the open state to the closed state by means of the hydraulic medium from the actuating device.
[0019] The invention makes it possible to fluidically couple hydraulic circuits, which are conventionally completely separated from one another and thus completely separate, as needed. This makes it possible, for example, to design the pumps differently in terms of their performance and / or size and thus weight, so that, for example, the second pump can be designed to be smaller or smaller than the first pump in terms of its performance and / or weight and / or size. This allows the costs, space requirements, and weight of the electric drive device to be kept particularly low.Furthermore, the probability of failure of the drive system can be kept particularly low because, for example, if one of the pumps, in particular the second pump, fails, both circuits can be supplied with the hydraulic medium, in particular from the reservoir, by the still intact other pump, in particular the first pump. In other words, if one pump fails, the hydraulic medium can be pumped through both circuits by the still intact other pump.
[0020] Preferably, the valve device is designed as a one-way valve, via which the hydraulic medium can be led from the high-pressure circuit into the low-pressure circuit when the valve device is in the open state.
[0021] The invention is based in particular on the following findings and considerations: The high-pressure circuit and the first pump are particularly designed to generate a high pressure, such as the first pressure of the hydraulic medium, in order to thereby actuate the coupling device. The low-pressure circuit and the second pump are particularly designed to achieve a high volume flow of the hydraulic medium in order to advantageously cool at least the subregions of the electric machine and, for example, to advantageously supply at least one further component with the hydraulic medium and thus lubricate and / or cool it using the hydraulic medium.The two pumps are used in particular because they allow for a better overall energy balance than if a pump shared by both circuits were used, which is designed to provide both a sufficiently high pressure to actuate the coupling device and a sufficiently high flow rate to adequately cool the electrical machines. The use of two pumps in the invention ensures energy-efficient operation.Furthermore, the invention makes it possible, because the high-pressure circuit can be fluidically connected to the low-pressure circuit via the connecting device and the valve device, to assist the second pump in conveying the hydraulic medium by means of the first pump and, for example, to guide at least a portion of the hydraulic medium conveyed by the first pump and flowing through at least a portion of the high-pressure circuit from or out of the high-pressure circuit via the connecting device and via the valve device to and into the low-pressure circuit, thus conveying the hydraulic medium from the high-pressure circuit into the low-pressure circuit by means of the first pump via the valve device and via the connecting device.
[0022] In order to be able to fluidically connect the circuits to one another in a particularly tailored manner, one embodiment of the invention provides that the connecting device is fluidically connected to the high-pressure circuit at, in particular at least or precisely, a first connection point and to the low-pressure circuit at, in particular at least or precisely, a second connection point. The actuating device is fluidly connected to the high-pressure circuit at at least one third connection point spaced apart from the first connection point and also from the second connection point, such that by means of the actuating device at least part of the hydraulic medium flowing through the high-pressure circuit can be branched off from the high-pressure circuit at the third connection point and guided to the valve device.
[0023] It has proven particularly advantageous if the third connection point is located downstream of the first connection point in the direction of flow of the hydraulic medium flowing through the high-pressure circuit. This ensures that the valve device can be switched over particularly precisely as needed.
[0024] In a further embodiment of the invention, it is provided that the third connection point is arranged downstream of the first connection point, viewed in the flow direction of the hydraulic medium flowing through the high-pressure circuit, and downstream of a line element of the high-pressure circuit, wherein the coupling device can be supplied with the hydraulic medium via the valve and the line element. The valve can be switched between a blocking state that fluidically blocks the line element and a release state that releases the line element. This makes it possible to allow or make the actuation of the valve device dependent on the actuation of the coupling device, so that a particularly needs-based actuation of the valve device can be achieved in a particularly simple manner.
[0025] It has also proven particularly advantageous if the third connection point is arranged upstream of the coupling device in the high-pressure circuit, whereby the actuation of the valve device can be made dependent on the actuation of the coupling device in a particularly advantageous and particularly simple manner. Thus, the valve device can be actuated particularly as needed, enabling particularly energy-efficient operation.
[0026] In order to be able to realize a particularly advantageous and in particular demand-oriented and energy-efficient operation of the drive device, it is provided in a further embodiment of the invention that the coupling device has two switching elements that can be actuated by means of the hydraulic medium, namely a first switching element and a second switching element.
[0027] It has proven particularly advantageous if the valve device has a differential pressure slide as the first slide, which can be moved along a particularly straight axis of movement relative to a slide housing, and a main slide as the second slide, which can be moved along the axis of movement relative to the slide housing, wherein in particular the slides are movable relative to one another along the axis of movement. The main slide is also referred to as the main pressure slide. The slides are arranged directly one behind the other, i.e. one after the other, when viewed along the axis of movement. The main slide (main pressure slide) has a first pressure surface which can be acted upon by the hydraulic medium for actuating the first switching element, whereby the main pressure slide is movable along the axis of movement in a first direction, in particular relative to the slide housing.The main spool has a second pressure surface which, for example, points away from the first pressure surface along the movement axis, so that, for example, the first pressure surface and the second pressure surface point away from each other in a movement axis. The second pressure surface can be acted upon by the hydraulic medium pumped by the first pump, whereby the main spool can be displaced along the movement axis in a second direction opposite to the first direction, in particular relative to the spool housing. The differential pressure spool has a third pressure surface which can be acted upon by the hydraulic medium for actuating the second switching element, whereby the differential pressure spool can be displaced along the movement axis in the first direction relative, in particular to the spool housing.Furthermore, the differential pressure slide valve has a fourth pressure surface, which points away from the third pressure surface, for example along the movement axis, so that, for example, the third pressure surface and the fourth pressure surface point away from each other along the movement axis. The fourth pressure surface can be acted upon by the hydraulic medium to actuate the first switching element, whereby the differential pressure slide valve can be displaced along the movement axis in the second direction, in particular relative to the slide valve housing. For example, the hydraulic medium has a first actuating pressure to actuate the first switching element, so that the first pressure surface can be acted upon by the first actuating pressure. For example, a first spring is provided, which is arranged, for example, in the slide valve housing. For example, the first pressure surface is operatively connected to the first spring.The first spring can, for example, provide a spring force acting in particular along the movement axis, which can, for example, act on the first pressure surface along the movement axis. Because the first pump delivers the hydraulic medium, the first pump, for example, causes a pump pressure of the hydraulic medium, wherein the pump pressure can correspond to the first actuation pressure or can be less than the first actuation pressure. For example, the first actuation pressure can be effected or is effected by means of the pump. The second pressure surface can thus be subjected to the pump pressure effected by the pump. To actuate the second switching element, for example, the hydraulic medium has a second actuation pressure, which can be effected or is effected by means of the first pump. The second actuation pressure can be greater than, less than, or equal to the first actuation pressure.Furthermore, it is conceivable that the pump pressure corresponds to the second actuating pressure or is lower than the second actuating pressure. The third pressure surface can thus be acted upon by means of the second actuating pressure. In addition, the fourth pressure surface can thus be acted upon by the first actuating pressure. For example, the first spring is a mechanical spring, and therefore designed as a solid body. The valve device can have a second spring, which is provided in particular in addition to the first spring and is preferably designed as a mechanical spring, and therefore as a solid body. For example, the second spring is arranged in the slide housing. In this case, it is conceivable that the first pressure surface is operatively connected to the second spring. Furthermore, it is conceivable that the fourth pressure surface is operatively connected to the second spring.Thus, for example, the second spring is arranged between the first pressure surface and the fourth pressure surface, particularly when viewed along the movement axis. The second spring can, for example, particularly when tensioned, provide a second spring force acting particularly along the movement axis, which second spring force can act, particularly along the movement axis, on the fourth pressure surface and the first pressure surface. The first spring is arranged, for example, between the third pressure surface and a wall of the slide housing, viewed along the movement axis, so that, for example, the second spring can be or is supported on the one hand on the wall and on the other hand on the third pressure surface along the movement axis. Accordingly, for example, the second spring is supported or is supportable on the one hand on the first pressure surface and on the other hand on the fourth pressure surface along the movement axis.Thus, for example, the differential pressure slide valve is arranged along the movement axis between the first spring and the second spring. If, for example, the differential pressure slide valve is displaced along the movement axis in the second direction relative to the slide valve housing, this tensions the first spring, for example, whereby the first spring provides the aforementioned spring force, also referred to as the first spring force. Thus, for example, the differential pressure slide valve can be displaced relative to the slide valve housing in the first direction by means of the first spring force.If, for example, the main slide is displaced in the second direction relative to the slide housing and also relative to the differential pressure slide, so that the main slide and thus its first pressure surface are pushed out of the differential pressure slide and thus toward the fourth pressure surface, the second spring is thereby tensioned, in particular compressed, whereby the second spring provides the second spring force. By means of the second spring force, for example, the differential pressure slide can be displaced in the second direction relative to the slide housing and / or by means of the second spring force, the main slide can be displaced in the first direction relative to the slide housing.If, for example, the differential pressure slide is displaced in the first direction relative to the slide housing by means of the first spring, i.e. by means of the first spring force, the differential pressure slide can, for example, be supported on the main slide along the movement axis via the second spring, so that, for example, the main slide is displaced or can be displaced in the first direction relative to the slide housing via the second spring. Furthermore, it is conceivable that when, for example, the differential pressure slide is displaced in the first direction relative to the slide housing and also relative to the main slide, so that the fourth pressure surface is pushed towards the first pressure surface, the second spring is tensioned, whereby the second spring provides the second spring force.By means of the second spring force, the differential pressure slide can be moved in the second direction relative to the slide housing and / or by means of the second spring force, the main slide can be moved in the first direction relative to the slide housing. It can be seen that this enables a simple, space-saving and cost-effective displacement of the slides and thus an actuation of the valve device, wherein this displacement of the slides and thus this actuation of the valve device is pressure-dependent, i.e. depends on the aforementioned actuation pressures and the pump pressure and, in particular, on a respective ratio of the actuation pressures and the pump pressure to one another. In this way, a demand-based actuation of the valve device can be realized in a particularly simple, space-saving, weight-saving and cost-effective manner, so that the circuits can be fluidically connected to one another as required.In particular, this makes it possible, for example, to switch the valve device from the closed state to the open state as soon as at least one of the two applies: a force resulting from the pump pressure and acting on the second pressure surface and in particular acting along the movement axis is greater than a sum of a force resulting from the first actuating pressure and in particular acting along the movement axis on the first pressure surface and the first spring force, or a force resulting from the pump pressure and in particular acting along the movement axis on the second pressure surface is greater than a sum of a force resulting from the second actuating pressure and in particular acting along the movement axis on the third pressure surface and the second spring force.In particular, the following advantage can be realized: For operating situations in which the first pump actually provides unnecessary, i.e. unnecessarily large, quantities of hydraulic medium, so that at least one of the previously mentioned conditions is met, the excess hydraulic medium delivered by the first pump is guided from the high-pressure circuit via the valve device and via the connecting device into the low-pressure circuit and thus made available to the low-pressure circuit and can therefore be used efficiently.
[0028] It has proven particularly advantageous if the valve device can be switched to the open state by moving the main slide in the second direction, whereby a particularly advantageous and demand-oriented actuation of the valve device can be achieved.
[0029] Finally, it has proven particularly advantageous for the realization of a particularly advantageous and demand-oriented fluidic connection of the circuits if the main slide has a control edge and is designed as a control slide.
[0030] A second aspect of the invention relates to a method for operating an electric drive device according to the first aspect of the invention. Advantages and advantageous embodiments of the first aspect of the invention are to be regarded as advantages and advantageous embodiments of the second aspect of the invention, and vice versa.
[0031] The first switching element can be switched, for example, between a first switching element coupling state and a first switching element decoupling state, wherein, for example, by actuating the first switching element, the first switching element can be switched from the first switching element decoupling state to the first switching element coupling state. The second switching element can be switched, for example, between a second switching element coupling state and a second switching element decoupling state, wherein, for example, by actuating the second switching element, the second switching element can be switched from the second switching element decoupling state to the second switching element coupling state. In a first operating state of the electric drive device, for example, the first switching element is in the first switching element coupling state, while the second switching element is in the second switching element decoupling state.As a result, the coupling device is in the coupled state, so that, for example, the vehicle wheels can be driven by the second electric machine, i.e., the second rotor, via the first switching element, in particular in such a way or by the fact that the second electric machine, in particular the second rotor, can be coupled or is coupled to the vehicle wheels in a torque-transmitting manner via the first switching element, in particular, with respect to the switching elements, exclusively via the first switching element. In a second operating state of the drive device, for example, the first switching element is in the first switching element decoupling state, while the second switching element is in the second switching element coupling state.The coupling device is thus in the coupled state, wherein, for example, the vehicle wheels can be driven by the second electrical machine, in particular the second rotor, via the coupling device and thereby via the second switching element, in particular exclusively via the second switching element with regard to the switching elements, for example in such a way that the second electrical machine, in particular the second rotor, can be or is coupled to the vehicle wheels in a torque-transmitting manner via the second switching element, in particular exclusively via the second switching element with regard to the switching elements. In a third operating state of the electric drive device, for example, the first switching element is in the first switching element coupling state, while the second switching element is in the second switching element coupling state, such that the switching elements are in their switching element coupling states.As a result, the coupling device is in its coupled state, so that, for example, the vehicle wheels can be driven by the second electrical machine, in particular the second rotor, via the coupling device and thereby via the switching elements, in particular in such a way that the vehicle wheels are or can be coupled in a torque-transmitting manner to the second electrical machine, in particular the second rotor, via the switching elements. In a fourth operating state of the electric drive device, for example, the first switching element is in the first switching element decoupling state, while the second switching element is in the second switching element decoupling state. Thus, for example, in the fourth operating state, the switching elements are in the switching element decoupling states, as a result of which the coupling device is in the decoupling state.This enables particularly needs-based and efficient operation of the electric drive system.
[0032] It has proven particularly advantageous if the first shifting element and the second shifting element are designed as multi-plate shifting elements, in particular as multi-plate clutches. The multi-plate shifting elements are preferably conventional hydraulically actuated or actuatable multi-plate shifting elements which, in their respective switched-on or closed state, i.e. in their respective shifting element coupling state, must be permanently actuated, i.e., pressurized and actuated by the hydraulic medium, in order to hold the shifting elements in the switching element coupling states. If, for example, an initially established supply of the hydraulic medium to the respective shifting element is terminated, this causes or allows the respective shifting element to be switched from its respective shifting element coupling state to its respective shifting element decoupling state or to return.
[0033] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective specified combinations, but also in other combinations or on their own, without departing from the scope of the invention.
[0034] The drawing shows: Fig. 1 a schematic representation of an electric drive device for a motor vehicle; Fig. 2 a further schematic representation of the drive device; and Fig. 3 a flowchart illustrating a method for operating the electric drive device.
[0035] Fig. Figure 1 shows a schematic representation of an electric drive device 10 for a motor vehicle, also referred to simply as a vehicle. The motor vehicle can be driven, in particular purely electrically, by means of the electric drive device 10. The motor vehicle has at least or exactly two vehicle axles arranged consecutively and thus one behind the other in the longitudinal direction of the motor vehicle, namely a first vehicle axle and a second vehicle axle.
[0036] In particular, exactly one of the vehicle axles comprises the electric drive device 10. The respective vehicle axle has at least or exactly two respective vehicle wheels, which are arranged on opposite sides in the transverse direction of the motor vehicle. The transverse direction of the vehicle is in Fig. 1 by a double arrow 12. The vehicle wheels of the vehicle axle comprising the drive device 10 are in Fig. 1 and designated 14 and 16. By means of the drive device 10, the vehicle wheels 14 and 16 can be driven, in particular purely electrically, whereby the motor vehicle can be driven, in particular purely electrically. The electric drive device 10 has a Fig. 1 particularly schematically illustrated housing 18 and a coupling device 20 arranged in particular in the housing 18, which has a first switching element 22 and a second switching element 24. The switching elements 22 and 24 are frictionally engaged switching elements and in this case are designed as multi-plate switching elements, in particular as multi-plate clutches. The respective switching element 22, 24 can be switched between a respective switching element coupling state and a respective switching element decoupling state, wherein when at least or exactly one of the switching elements 22, 24 is in its switching element coupling state, the coupling device 20 is in its coupling state. In other words, if exactly one of the switching elements 22 and 24 is in its switching element coupling state, while the respective other switching element 24, 22 is in its switching element decoupling state, the coupling device 20 is in its coupling state.If both switching elements 22, 24 are simultaneously in their switching element coupling states, the coupling device 20 is in its coupling state. If both switching elements 22, 24 are simultaneously in their switching element decoupling states, the coupling device 20 is in its decoupling state.
[0037] The electric drive device 10 has a first electric machine 26, which has a first stator 28 and a first rotor 30. Furthermore, the electric drive device 10 has a second electric machine 32, which has a second stator 34 and a second rotor 36. In the exemplary embodiment shown in the figures, the respective electric machine 26, 32 is designed as an axial flux machine (AFM). The respective switching element 22, 24 can be actuated hydraulically, wherein by hydraulic actuation of the respective switching element 22, 24, the respective switching element 22, 24 can be adjusted, i.e., switched, from its respective switching element decoupling state to its respective switching element coupling state.
[0038] The vehicle wheels 14 and 16 can be driven by means of the electric machines 26 and 32, in particular via a differential gear 38 of the electric drive device 10, also referred to simply as a differential. In order to drive the vehicle wheels 14 and 16 with respect to the electric machines 26 and 32 exclusively by means of the electric machine 26, for example, both switching elements 22 and 24, also referred to as clutches, are opened simultaneously, thus both switching elements 22 and 24 are simultaneously in their switching element decoupling states, so that the coupling device 20 is in its decoupling state.In order to drive, for example, the vehicle wheels 14 and 16, in particular simultaneously, by means of both electric machines 26 and 32, the coupling device 20 is in its coupling state, so that, for example, either exactly one of the switching elements 22 and 24 is closed, thus is in its switching element coupling state, or both switching elements 22 and 24 are closed simultaneously, thus are in their switching element coupling states simultaneously.
[0039] It can be seen that the second electric machine 32, i.e., its second rotor 36, is decoupled from the vehicle wheels 14 and 16 in the uncoupled state of the coupling device 20. In the coupled state of the coupling device 20, the electric machine 32, in particular the rotor 36, is coupled or can be coupled to the vehicle wheels 14 and 16 in a torque-transmitting manner, so that in the coupled state of the coupling device 20, the vehicle wheels 14 and 16 can be driven by the electric machine 32, i.e., by the rotor 36.
[0040] In addition, the vehicle wheels 14 and 16 can be driven by means of the electric machine 26, that is to say by means of the rotor 30, bypassing the coupling device 20, so that the electric machine 26, in particular the rotor 30, can drive the vehicle wheels 14 and 16 both in the coupled state and in the uncoupled state of the coupling device 20.
[0041] Particularly good looking Fig. 2 that the drive device 10 has a high-pressure circuit 40 through which a liquid hydraulic medium can flow, which is also referred to as the first circuit, first circuit, or high-pressure circuit. Via the high-pressure circuit 40, the switching elements 22 and 24, and thus the coupling device 20, can be supplied with the hydraulic medium flowing through the high-pressure circuit 40, i.e., with the hydraulic medium from the high-pressure circuit 40. The electric drive device 10 also has a low-pressure circuit 42 through which the hydraulic medium can flow, which is also referred to as the second circuit, second circuit, or low-pressure circuit. The hydraulic medium flowing through the low-pressure circuit 42 is used as a cooling medium to cool at least respective portions of the electric machines 26 and 32. Fig. 2 shows that the stator 34, the stator 28, the rotor 30 and the rotor 36 can be supplied with the hydraulic medium flowing through the low-pressure circuit 42, i.e. with the hydraulic medium from the low-pressure circuit 42, via the low-pressure circuit 42, so that the rotors 30 and 36 and the stators 28 and 34 can be cooled by means of the hydraulic medium flowing through the low-pressure circuit 42. A first further component of the drive device 10 is shown in Fig. 2 is designated 44, and a second further component of the drive device 10 is designated 46, wherein the components 44 and 46 can also be supplied with the hydraulic medium flowing through the low-pressure circuit 42 via the low-pressure circuit 42, in order to thereby also be able to cool and / or lubricate the components 44 and 46 by means of the hydraulic medium (cooling medium) flowing through the low-pressure circuit 42. The stators 28 and 32, the rotors 30 and 36, and the components 44 and 46 are also referred to as consumers. It can be seen that a distribution element 48 common to the consumers, which is also referred to as a rail, is arranged in the low-pressure circuit 42.The consumers can be supplied with the hydraulic medium via the distribution element 48, in particular in such a way that the stator 34 can be supplied with the hydraulic medium from the low-pressure circuit 42, in particular from the distribution element 48, via its own first valve 50 and the stator 28 can be supplied with the hydraulic medium from the low-pressure circuit 42, in particular from the distribution element 48, via its own second valve 52. A third valve 54 is provided which is common to the rotors 30 and 36 and via which the rotors 30 and 36 can be supplied with the hydraulic medium from the distribution element 48. Also provided is a fourth valve 56 which is common to the components 44 and 46 and via which the components 44 and 46 can be supplied with the hydraulic medium from the distribution element 48. It can be seen that the valves 50, 52, 54 and 56 are arranged in the low-pressure circuit 42, in each case downstream of the distribution element 48 and upstream of the consumers.
[0042] The high-pressure circuit 40 has a first line element 58 and a second line element 60, which are, for example, at least partially fluidically separated from one another. A fifth valve 62 is arranged in the line element 58 and thus in the high-pressure circuit 40. It can be seen that the first switching element 22 can be supplied with the hydraulic medium flowing through the high-pressure circuit 40 via the line element 58 and the valve 62, so that the hydraulic medium flowing through the high-pressure circuit 40 can be fed to the first switching element 22 via the line element 58 and the valve 62. The valve 62 can be switched between a blocking state that fluidically blocks the line element 58 and at least one release state that fluidically releases the line element 58.A sixth valve 63 is arranged in the second line element 60, so that the second switching element 24 can be supplied with the hydraulic medium flowing through the high-pressure circuit 40 via the line element 60 and the valve 63. This means that the hydraulic medium flowing through the high-pressure circuit 40 can be supplied to the second switching element 24 via the line element 60 and the valve 63. The valve 63 can be switched between a blocking state that fluidically blocks the line element 60 and at least one release state that releases the line element 60. In particular, a respective quantity of hydraulic medium flowing through the respective line element 58, 60 and to be supplied to the respective switching element 22, 24 can be adjusted by means of the respective valve 62, 63.
[0043] The electric drive device 10 has a first pump 64 arranged in the high-pressure circuit 40, by means of which the hydraulic medium can be pumped out of a reservoir 66 common to the circuits, also referred to as a tank or designed as a tank, and through the high-pressure circuit 40. In the low-pressure circuit 42, a second pump 68 is provided in addition to the pump 64, by means of which the hydraulic medium can be pumped out of the reservoir 66 and through the low-pressure circuit 42. The pumps 64 and 68 are preferably electric pumps, i.e., electrically operated pumps.
[0044] The electric drive device 10 has a connecting device 70 for fluidically connecting the high-pressure circuit 40 to the low-pressure circuit 42. A valve device 72 is arranged in the connecting device 70, which valve device can be switched between a closed state, which fluidically blocks the connecting device 70, as the first state, and an open state, which releases the connecting device 70, as the second state, in which the high-pressure circuit 40 is fluidically connected to the low-pressure circuit 42 via the connecting device 70. In the closed state, the circuits are not fluidically connected to one another via the connecting device 70. Fig. 2, arrows illustrate a respective flow of the hydraulic medium through the high-pressure circuit 40, the low-pressure circuit 42 and the connecting device 70, so that according to Fig. 2 the connecting device 70 is open, thus in its open state.
[0045] The electric drive device 10 also has an actuating device 74 provided in addition to the connecting device 70, which comprises a first actuating line 76, a second actuating line 78, and a third actuating line 80. By means of the actuating device 74, at least a portion of the hydraulic medium flowing through at least part of the high-pressure circuit 40 can be branched off from the high-pressure circuit and guided to the valve device 72, which can be actuated by means of the hydraulic medium from the actuating device 74 and can thus be switched from one of the states to the other state and preferably also from the other state to one state.
[0046] Out of Fig. 2 that the connecting device 70 is fluidically connected to the high-pressure circuit 40 at a first connection point V1 and fluidically connected to the low-pressure circuit 42 at a second connection point V2. The actuating line 76 and thus the actuating device 74 are fluidically connected to the line element 58 and thus to the high-pressure circuit 40 at a third connection point V3. The actuating line 78 and thus the actuating device 74 are fluidically connected to the line element 60 and thus to the high-pressure circuit 40 at a fourth connection point V4. Furthermore, the actuating line 80 and thus the actuating device 74 are fluidically connected to the high-pressure circuit 40 at a fifth connection point V5. The connection points V1 and V5 can coincide, or the connection points V1 and V5 can be spaced apart from one another.It can be seen that the connection points V1 and V5 are arranged downstream of the pump 64 and upstream of the valves 62 and 64, in particular upstream of the line elements 58 and 60, in particular in the high-pressure circuit 40. The respective connection point V3, V4 is arranged downstream of the respective connection point V1, V5, and the respective connection point V3, V4 is arranged downstream of the respective valve 62, 64 in the respective line element 58, 60, wherein the respective connection point V3, V4 is arranged upstream of the respective switching element 22, 24 in the respective line element 58, 60. The hydraulic medium flowing through the line element 58 has, for example, a first actuation pressure and is provided for actuating the switching element 22. The hydraulic medium flowing through the line element 60 has, for example, a second actuation pressure and is provided for actuating the switching element 24.Thus, the first actuation pressure is provided for actuating the switching element 22 and the second actuation pressure is provided for actuating the switching element 24. The hydraulic medium delivered by the pump 64 has, for example, at the connection point V5, a pump pressure which can correspond to the first actuation pressure and / or the second actuation pressure. Furthermore, the pump pressure is, for example, lower than the first actuation pressure and / or the second actuation pressure. It can be seen that by means of the actuation line 76 and thus by means of the actuation device 74, at least a portion of the hydraulic medium flowing through the line element 58 can be branched off from the line element 58 and guided to the valve device 72. Thus, so to speak, the first actuation pressure can be guided to the valve device 72.By means of the actuating line 78 and thus by means of the actuating device 74, at least a portion of the hydraulic medium flowing through the line element 60 can be branched off from the line element 60 and guided to the valve device 72, so that, so to speak, the second actuating pressure can be guided to the valve device 72. At the connection point V5, by means of the actuating line 80 and thus by means of the actuating device 74, at least a portion of the hydraulic medium delivered by the pump 64 and flowing through at least a portion of the high-pressure circuit 40 can be branched off from the high-pressure circuit 40 and guided to the valve device 72, so that, so to speak, the pump pressure can be guided to the valve device 72.The first actuation pressure, the second actuation pressure, and the pump pressure are collectively referred to as valve pressures, since the valve device 72 is actuated by means of the valve pressures and, in particular, depending on a respective ratio of the valve pressures to one another and can thus be switched from one state to the other, and, for example, also from the other state to the one state. It can be seen that the connection point V2 is arranged downstream of the pump 68 and upstream of the distribution element 48 in the low-pressure circuit 42.
[0047] The valve device 72 has a differential pressure slide 88, also referred to as the first slide. The differential pressure slide 88 is displaceable, i.e., translationally movable, along a particularly straight movement axis 84 relative to a slide housing 86 of the valve device 72. The valve device 72 also has a main slide 82, also referred to as the main pressure slide, which is displaceable, i.e., translationally movable, along the movement axis 84 relative to the slide housing 86. The main slide 82 is also referred to as the second slide. The slides are arranged directly one behind the other along the movement axis 84.The main spool 82 has a first pressure surface D1, which can be acted upon by the hydraulic medium from the actuation line 76 and thus by the hydraulic medium for actuating the switching element 22 and thus by the first actuation pressure, whereby the main spool 82 can be displaced along the movement axis 84 in a first direction, illustrated by an arrow 90, relative to the spool housing 86. The main spool 82 has a second pressure surface D2, wherein the pressure surfaces D1 and D2 point away from one another along the movement axis 84. The second pressure surface D2 can be acted upon by the hydraulic medium from the actuation line 80 and thus by the hydraulic medium delivered by the pump 64 and thus by the pump pressure, whereby the main spool 82 can be displaced along the movement axis 84 in a second direction, opposite to the first direction and illustrated by an arrow 92, relative to the spool housing 86.The differential pressure slide 88 has a third pressure surface D3, which faces away from the pressure surfaces D1 and D2 along the movement axis 84. The third pressure surface D3 can be acted upon by the hydraulic medium from the actuation line 78 and thus by the hydraulic medium for actuating the switching element 24 and thus by the second actuation pressure, whereby the differential pressure slide 88 can be displaced along the movement axis 84 in the first direction relative to the slide housing 86. The differential pressure slide 88 also has a fourth pressure surface D4, which faces away from the pressure surface D3 along the movement axis 84, thus facing away, with the pressure surface D4 facing the pressure surface D1 along the movement axis 84. This means that the pressure surfaces D1 and D4 face each other along the movement axis 84. The pressure surfaces D3 and D4 face away from each other along the movement axis 84.The pressure surface D4 can be subjected to the hydraulic medium from the actuation line 76 and thus to the hydraulic medium for actuating the switching element 22 and thus to the first actuation pressure, whereby the differential pressure slide 88 can be displaced in the second direction along the movement axis 84 relative to the slide housing 86. A first spring 94 is arranged along the movement axis 84 between the pressure surfaces D1 and D2 and thus between the slides, which can be or is supported along the movement axis 84 on the pressure surfaces D1 and D4, in particular directly in each case. The spring 94 is arranged, for example, in the slide housing 86. A second spring 96 is arranged along the movement axis 84 between the pressure surface D3 and a wall of the slide housing 86, which second spring 96 can be or is supported along the movement axis 84 on the wall and on the pressure surface D3, in particular directly in each case.In particular, the respective spring 94, 96 is designed as a compression spring. By tensioning, in particular compressing, the spring 94, the spring 94 can provide a first spring force, by means of which, for example, the main slide 82 can be displaced in the first direction and / or the differential pressure slide 88 in the second direction. By tensioning, in particular compressing, the spring 96, the spring 96 can provide a second spring force, by means of which, for example, the differential pressure slide 88 and, for example via this and via the spring 94, the main slide 82 can be displaced in the first direction. For example, the pressure areas D1, D2, D3 and D4 are the same. For example, the first actuation pressure and the second actuation pressure are the same.
[0048] The main slide 82 is displaceable, for example, between a closed position and at least one open position along the movement axis 84 relative to the slide housing 86. The closed position, for example, causes the valve device 72 to be closed, and the open position of the main slide 82, for example, causes the valve device 72 to be open. For example, the main slide 82 can be moved from the closed position to the open position by displacing the main slide 82 in the second direction. By displacing the main slide 82 in the first direction, the main slide 82 can be moved, i.e., displaced, from the open position to the closed position.If, for example, a force resulting from the pump pressure and acting along the movement axis 84, in particular in the second direction on the pressure surface D2, is greater than a sum of a force resulting from the first actuating pressure and acting along the movement axis 84 and in particular in the first direction on the pressure surface D1 and the first and / or second spring force acting or acting along the movement axis 84 in the first direction, the main slide 82 is moved from the closed position to the open position, whereby the valve device 72 is switched from the closed state to the open state.For example, if the force resulting from the pump force acting along the movement axis 84 and in the second direction on the pressure surface D2 is greater than the sum of the force resulting from the second actuating pressure acting along the movement axis 84 and in particular in the first direction on the pressure surface D3 and the first and / or second spring force, the main slide 82 is moved from the closed position to the open position, thereby opening the valve device 72, thus switching from the closed state to the open state. This ensures simple and needs-based switching of the valve device 72 between the states.
[0049] In principle, it would be conceivable for the valve device 72 to be designed as a pressure relief valve. In the exemplary embodiment shown in the figures, however, the valve device 72 is designed as a slide valve with the aforementioned slides. This ensures that the first actuating pressure and / or the second actuating pressure keeps the valve device 72 closed, i.e., in the closed state. Only when the first pump 64, designed or functioning, for example, as a high-pressure pump, further increases a volume flow of the hydraulic medium effected by the pump 64, does the pump pressure increase, ultimately opening the valve device 72. As a result, the hydraulic medium delivered by the pump 64 flows at least partially from the high-pressure circuit 40 into the low-pressure circuit 42 via the connecting device 70.The said volume flow of the hydraulic medium is effected by means of the pump 64 in that the pump 64 conveys the hydraulic medium.
[0050] Since the maximum volume flow of the hydraulic medium is not needed when the high-pressure circuit 40 requires the maximum pressure of the hydraulic medium, the pump 64 can assist the pump 68 in pumping the hydraulic medium by flowing at least a portion of the hydraulic medium pumped by the pump 64 from the high-pressure circuit 40 into the low-pressure circuit 42 via the connecting device 70. As a result, the pump 68 can advantageously be designed to be small, thus allowing the low-load pumps to operate particularly efficiently.
[0051] If, for example, the pump 68 fails, an emergency supply to the low-pressure circuit can be ensured by means of the pump 64, in that the pump 64 can then pump the hydraulic medium and in particular from the reservoir 66 via at least a part of the high-pressure circuit 40 via the connecting device 70 into the low-pressure circuit 42 and in particular through the low-pressure circuit 42. This emergency supply, also referred to as emergency operation, is, for example, in Fig. 3 illustrates. Fig. 3 shows a flow chart, based on which a method for operating the electric drive device 10 is illustrated below, wherein in Fig. 3 particularly illustrates emergency care.
[0052] The method starts, for example, at a block B1. At a block B2, for example, an operating point, in particular a current one, of the electric drive device 10 is determined, i.e., ascertained, in particular as a function of input variables E1. The input variables include, for example, a driver request, in particular an accelerator pedal position. The driver request is or includes a drive torque to be provided by the drive device 10 to drive the motor vehicle. Furthermore, the input variables E1 include, for example, a temperature of the hydraulic medium as well as requests from control units and / or other input variables. At a block B3, for example, an oil requirement of the coupling device 20 is ascertained. At a block B4, for example, an oil requirement of a transmission, which is or includes, for example, the differential gear 38, is ascertained, and at a block B5, for example, an oil requirement of the rotors 30 and 36 is ascertained.In block B6, it is determined whether the drive device 10 is in dual operation. Dual operation means that the vehicle wheels 14 and 16 are driven simultaneously by the electric machines 26 and 32. If the drive device 10 is operated in dual operation, it is determined in block B7 that both stators 28 and 34 require oil and are therefore supplied with the hydraulic medium and should therefore be cooled by the hydraulic medium. If it is determined in block B6 that the drive device 10 is not in dual operation, so that with regard to the electric machines 26 and 32, the vehicle wheels 14 and 16 are driven exclusively by the electric machine 26, then in block B8 it is determined that with regard to the stators 28 and 34, only the first stator 28 requires oil, i.e., it is supplied with the hydraulic medium and should therefore be cooled by the hydraulic medium.Depending on the results of blocks B3, B4, B5, B7, and B8, a block B9 determines whether, for example, a sum of the oil requirements determined in blocks B3, B4, B5, B7, and B8, related to pumps 64 and 68, can be served exclusively by pump 64. If this is the case, pump 64 is controlled in block B10, so that, for example, related to pumps 64 and 68, the hydraulic medium is pumped exclusively by pump 64, for example through the low-pressure circuit 42. If it is determined in block B9 that the sum of the oil requirements cannot be served by pump 64 alone, a current operating point of pump 68, for example, is determined in block B11, and a volume flow of the hydraulic medium to be brought about or brought about or can be brought about by the second pump 68 is determined in block B12.For example, in block B11, the operating point of the second pump 68 is determined as a function of second input variables E2, which include, for example, a rotational speed of the pump 68, a torque of the pump 68, the temperature of the hydraulic medium and, for example, a value or parameter that characterizes whether the drive device 10 is in dual operation or not.
[0053] In a block B13, the pump 64 is controlled and thus operated, and depending on the results of blocks B11 and B12, in particular additionally, in a block B14 the pump 68 is controlled and thus operated, so that subsequently the hydraulic medium is conveyed in particular simultaneously by means of the pumps 64 and 68, namely through the circuits, in particular in such a way that with regard to the pumps 64 and 68 the hydraulic medium is conveyed through the high-pressure circuit 40 exclusively by means of the pump 64, and that for example either with regard to the pumps 64 and 68 the hydraulic medium is conveyed through the low-pressure circuit 42 exclusively by means of the pump 68, or that the hydraulic medium is conveyed through the low-pressure circuit 42 by means of both pumps 64 and 68.
[0054] For example, starting the motor vehicle, the driver sets a desired torque, which is to be provided by the drive device 10 to drive the motor vehicle, by moving an accelerator pedal (also referred to as the gas pedal) to a position that produces the desired torque. The desired torque is the aforementioned driver command. This results in a speed of the motor vehicle (also referred to as the driving speed or vehicle speed) or a rotational speed of the electric drive device 10, i.e., the rotor 30 and / or 36. Further boundary conditions such as the current temperature of the hydraulic medium, requirements of a higher-level powertrain control unit, air conditioning requirements, etc.thus determine the current operating point of the electric drive device 10, whose current operating point is determined in block B2. Blocks B3, B4, B5 and B6 and, for example, also blocks B7 and B8 are components of a module also referred to as the first module, in which or by which quantity requirements are formed. The respective quantity requirement characterizes a respective quantity of hydraulic medium. The quantity requirements, also referred to as oil quantity requirements, depend, for example, directly on the determined operating point of the drive device 10 and are individual for respective components such as, for example, the switching elements 22 and 24, the transmission, the rotors 30 and 36 and the stators 28 and 34. The aforementioned sum is therefore a sum of the quantity requirements.The sum is also referred to as the total quantity or total oil quantity and then determines a delivery quantity to be set, also referred to as the pump oil delivery quantity, wherein block B9 determines whether or not the pump delivery quantity can be provided by the pump 64 alone by pumping the hydraulic medium. Also relevant is whether or not the drive device 10 is in dual mode. If the drive device 10 is in dual mode or if dual mode is requested, both electric machines 26 and 32 are active, which results in an additional cooling requirement for the second electric machine 32 and should be taken into account. Block B9 and, for example, also block B10 are components of a second module in which a comparison takes place between the calculated and, in particular, requested pump delivery quantity and a maximum quantity of hydraulic medium that can be provided by the first pump 64.If the delivery rate, and therefore the total oil quantity, is less than or equal to the maximum quantity of hydraulic medium that can be provided by pump 64, then pump 64 is the only one operated with respect to pumps 64 and 68, so that with respect to pumps 64 and 68 the hydraulic medium is pumped exclusively by pump 64, namely through both the high-pressure circuit 40 and the low-pressure circuit 42. If the determined total oil quantity is greater than the maximum volume flow of hydraulic medium that can be provided by pump 64 or than the maximum quantity of hydraulic medium that can be provided by pump 64, then there is a shortage, so that both pump 64 and pump 68 are operated, and so that the hydraulic medium is pumped by both pump 64 and pump 68.
[0055] Blocks B13 and B14, and also blocks B11 and B12, are components of a third module, for example. The control or operation (also) of the second pump 68 results, for example, on the one hand from determining the current operating point of the pump 68 and, on the other hand, from a difference between the total oil quantity or the pump delivery rate and the maximum amount of hydraulic medium that can be provided, i.e., delivered, by the pump 64. The current operating point of the second pump 68 results, for example, from requirements of the switching elements 22 and 24, which are, for example, clutches of a dual clutch.
[0056] This is to be understood in particular that the switching elements 22 and 24, and thus the coupling device 20, which is designed, for example, as the aforementioned dual clutch, has to set a respective specific pressure of the hydraulic medium at the switching elements 22 and 24, in particular as a function of a respective speed of the respective vehicle wheel 14, 16, as a function of a respective torque at the respective vehicle wheel 14, 16, as a function of the current temperature of the hydraulic medium, as well as as a function of a leak, and optionally as a function of at least one or more further variables. The aforementioned under-coverage, i.e. the difference between the total oil quantity and the maximum quantity of hydraulic medium that can be pumped by means of the pump 64, is then added, for example, as an additional speed requirement to the current operating point of the second pump 68.
[0057] A further advantage of the drive device 10 and the method is that in the event of a defect in the second pump 68, the first pump 64 can function as a temporary emergency lubrication system, so that a high level of reliability can be achieved. List of reference symbols 10 electric drive device 12 double arrow 14 vehicle wheel 16 vehicle wheel 18 housings 20 coupling device 22 first switching element 24 second switching element 26 first electric machine 28 first stator 30 first rotor 32 second electric machine 34 second stator 36 second rotor 38 differential gears 40 High-pressure circuit 42 Low-pressure circuit 44 Component 46 Component 48 Distribution element 50 valve 52 Valve 54 Valve 56 Valve 58 Line element 60 line element 62 Valve 63 Valve 64 Pump 66 Reservoir 68 Pump 70 connecting device 72 Valve device 74 Actuating device 76 Actuating cable 78 Actuating cable 80 actuating cable 82 main slide valves 84 Movement axis 86 valve housing 88 differential pressure slide valves 90 Arrow 92 Arrow 94 spring 96 spring B1-14 Block D1 printing area D2 printing area D3 printing area D4 printing area E1 Input variables E2 Input variables V1-5 connection point QUOTES CONTAINED IN THE DESCRIPTION
[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature
[0000] DE 10 2013 008 740 A1
[0002]
Claims
[1] Electric drive device (10) for a motor vehicle, comprising: - a coupling device (20) which can be switched between a coupling state and a decoupling state; - a first electric machine (26) by means of which vehicle wheels (14, 16) of the motor vehicle can be driven by bypassing the coupling device (20); - a second electrical machine (32) which is decoupled from the vehicle wheels (14, 16) in the uncoupled state and coupled or couplable to the vehicle wheels (14, 16) in the coupled state, by means of which the vehicle wheels (14, 16) can be driven via the coupling device (20) in the coupled state of the coupling device (20); - a high-pressure circuit (40) through which a hydraulic medium can flow, via which the coupling device (20) can be supplied with the hydraulic medium, by means of which the coupling device (20) can be switched from the uncoupling state to the coupling state; - a low-pressure circuit (42) through which the hydraulic medium can flow as a cooling medium, via which at least one respective partial area of the respective electrical machine (26, 32) can be supplied with the cooling medium for cooling at least the respective partial area; - a first pump (64) arranged in the high-pressure circuit (40), by means of which the hydraulic medium can be conveyed through the high-pressure circuit (40); - a second pump (68) arranged in the low-pressure circuit (42), by means of which the hydraulic medium can be conveyed through the low-pressure circuit (42); - a connecting device (70) for fluidically connecting the high-pressure circuit (40) to the low-pressure circuit (42); - a valve device (72) arranged in the connecting device (70), which can be switched between a closed state fluidically blocking the connecting device (70) as a first state and an open state releasing the connecting device (70) as a second state, in which the high-pressure circuit (40) is fluidically connected to the low-pressure circuit (42) via the connecting device (70); and - an actuating device (74) provided in addition to the connecting device (70), by means of which at least a part of the hydraulic medium flowing through the high-pressure circuit (40) can be branched off from the high-pressure circuit (40) and guided to the valve device (72), which can be actuated by means of the hydraulic medium from the actuating device (74) and can thereby be switched from one of the states to the other state. [2] Electric drive device (10) according to claim 1, characterized by , that: - the connecting device (70) is fluidly connected to the high-pressure circuit (40) at a first connection point (V1) and fluidly connected to the low-pressure circuit (42) at a second connection point (V3); and - the actuating device (74) is fluidically connected to the high-pressure circuit (40) at at least one third connection point (V3) spaced from the first connection point (V1), so that by means of the actuating device (74) at least the part of the hydraulic medium flowing through the high-pressure circuit (40) can be branched off from the high-pressure circuit (40) at the third connection point (V3) and guided to the valve device (72). [3] Electric drive device (10) according to claim 2, characterized by that the third connection point (V3) is arranged downstream of the first connection point (V1) in the high-pressure circuit (40). [4] Electric drive device (10) according to claim 3, characterized byin that the third connection point (V3) is arranged downstream of the first connection point (V1) and downstream of a valve (62) arranged in a line element (58) of the high-pressure circuit (40) in the line element (58), wherein the valve (62), via which the coupling device (20) can be supplied with the hydraulic medium, can be switched between a blocking state fluidically blocking the line element (58) and a release state releasing the line element (58). [5] Electric drive device (10) according to one of claims 2 to 4, characterized by that the third connection point (V3) is arranged upstream of the coupling device (20) in the high-pressure circuit (40). [6] Electric drive device (10) according to one of the preceding claims, characterized bythat the coupling device (20) has two switching elements (22, 24) which can be actuated by means of the hydraulic medium, namely a first switching element (22) and a second switching element (24). [7] Electric drive device (10) according to claim 6, characterized by , that: - the valve device (72) comprises: ◯ a differential pressure slide valve (88) as the first slide valve, which is displaceable along a movement axis (84) relative to a slide valve housing (86); and ◯ a main slide (82) as a second slide, which can be displaced along the movement axis (84) relative to the slide housing (86), wherein the slides are arranged directly one behind the other when viewed along the movement axis (84); - the main slide (82) has a first pressure surface (D1) which can be acted upon by the hydraulic medium for actuating the first switching element (22), whereby the main slide (82) can be displaced along the movement axis (84) in a first direction (90); - the main slide (82) has a second pressure surface (D2) which can be acted upon by the hydraulic medium conveyed by means of the first pump (64), whereby the main slide (82) can be displaced along the movement axis (84) in a second direction (92) opposite to the first direction (90); - the differential pressure slide (88) has a third pressure surface (D3) which can be acted upon by the hydraulic medium for actuating the second switching element (24), whereby the differential pressure slide (88) can be displaced along the movement axis (84) in the first direction (90); and - the differential pressure slide (88) has a fourth pressure surface (D4) which can be acted upon by the hydraulic medium for actuating the first switching element (22), whereby the differential pressure slide (88) can be displaced along the movement axis (84) in the second direction (92); [8] Electric drive device (10) according to claim 7, characterized by that by moving the main slide (82) in the second direction (92) the valve device (72) can be switched to the open state. [9] Electric drive device (10) according to claim 7 or 8, characterized by that the main slide (829) has a control edge and is designed as a control slide. [10] Method for operating an electric drive device (10) according to one of the preceding claims.