Hydraulic system for a motor vehicle

Abstract

The invention relates to a hydraulic system (135) for cooling or lubricating thermal consumers (225) and for actuating a clutch device (140) of a motor vehicle (105), wherein the system (135) comprises the following elements: a first pump (205) which is designed to provide a first or second volume flow of fluid, depending on the rotational direction of said pump; a clutch device (140) for establishing or decoupling an effective connection between a drive unit (115) of the motor vehicle (105) and an output; and a flow direction valve (215) which is arranged fluidically between a supply device (210) and the first pump (205) and which can be switched, depending on the direction of rotation of the first pump (205), either to a first switching state by the first volume flow or to a second switching state by the second volume flow, wherein the clutch device (140) is switched to a decoupled state in the first switching state of the flow direction valve (215) and to a coupled state in the second switching state of the flow direction valve (215). The invention also relates to a drive device (100) for a motor vehicle (105) having such a hydraulic system (135), and to a motor vehicle (105).

Description

[0001] Hydraulic system for a motor vehicle

[0002] The present invention relates to a hydraulic lubrication and / or cooling system for a motor vehicle, a drive device with such a hydraulic system and a motor vehicle with such a drive device.

[0003] DE 10 2016 115 925 B4 discloses a hydraulic actuation system for operating a parking lock. The system comprises an actuator for transferring the parking lock from a released position to a locked position and / or from the locked position to a released position.

[0004] One object of the present invention is to provide a hydraulic lubrication and / or cooling system that, in addition to lubricating and cooling thermal consumers, also enables the actuation of clutch devices of the motor vehicle, in particular a drive device. The system is intended to be equally applicable to wet sump and dry sump pump systems. The invention solves this problem by means of the subject matter of the independent claims. Subordinate claims specify preferred embodiments.

[0005] According to a first aspect of the invention, a hydraulic system for cooling or lubricating thermal consumers and for actuating a clutch device of a motor vehicle comprises the following elements: a first pump, which is configured to provide a first or second volume flow of fluid depending on its direction of rotation; a clutch device for generating or decoupling an operative connection between a drive unit of the motor vehicle and an output;and a flow direction valve which is fluidically arranged between a storage device and the first pump and which, depending on the direction of rotation of the first pump, can be switched either by the first volume flow into a first switching state or by the second volume flow into a second switching state, wherein the clutch device is switched to a decoupled state in the first switching state of the flow direction valve and to a coupled state in the second switching state of the flow direction valve. With such a hydraulic system, a separate actuator for actuating the clutch device, in particular an electric motor and possibly a supplementary gear stage for actuating the clutch device, can be dispensed with. The component and cost expenditure are thus relatively low. Furthermore, the system proposed here reduces the overall weight of the drive train.

[0006] The clutch device's switching is therefore robust and capable of strategy, i.e. it is comparatively less prone to errors and a variety of control methods for engaging the clutch device are conceivable, for example depending on the temperature response of the electric axle. In addition, different control variants can be implemented when engaging and / or disengaging the clutch device. Errors in the system are easy to diagnose and the switching can also be taught-in. Any wear or running-in processes in the mechanics, e.g. the end positions of the clutch device or a possible tooth-on-tooth position in a clutch device designed as a claw clutch or in hydraulic components, can be diagnosed and the switching sequence of the clutch device can be adapted accordingly. In addition, the acoustic properties can be improved, particularly during engagement and disengagement of the clutch device.

[0007] The first pump is preferably an electrically driven pump, in particular a gear pump, which can also be called a gerotor pump or Eaton pump, and which, through appropriate control, can, on the one hand, cool and / or lubricate thermal consumers and, on the other hand, actuate at least one clutch device, i.e., switch between an open and closed state. The first pump can be driven in two directions of rotation, wherein in the first direction of rotation of the first pump, the first volume flow is conveyed through a first fluid line, and wherein in the preferably opposite direction of rotation of the first pump, the second volume flow is conveyed through a fluid line of the system.The first pump draws coolant and / or lubricant from the reservoir and switches the flow direction valve to either the first switching state or the second switching state, depending on the direction of rotation of the first pump. Regardless of the switching state of the flow direction valve, the first pump is always supplied with fluid, which reaches the first pump through appropriately designed pockets of the flow direction valve. The reservoir is therefore configured to supply the first pump with fluid. A fluid used by the hydraulic system can, in particular, comprise oil. The fluid is used both for lubricating and for cooling elements of the drive device. The fluid is also used to actuate the clutch device.

[0008] The clutch device is to be understood as a separation unit or a so-called disconnect unit or disconnect unit (abbreviated to “DCU”). The clutch device comprises a clutch. The clutch device can advantageously be arranged at different positions in a drive device, in particular an electric axle of the motor vehicle. The clutch device can be effectively arranged in particular on a rotor shaft, for example between an electric machine and a transmission stage, or on an intermediate shaft, for example between a first spur gear stage and a second spur gear stage of the transmission stage, or in the region of a differential gear, which divides drive power between two output shafts, or on an output shaft of a drive train.

[0009] The clutch device preferably has a switching element, for example in the form of a switching piston or the like, which can be switched between two end positions, wherein one end position corresponds to the uncoupled state of the clutch device and the other end position to the coupled state of the clutch device. In the coupled state, an operative connection, i.e. a torque-transmitting connection, is created between two components, which is to be understood as "creating the operative connection between the drive unit of the motor vehicle and the output." In the uncoupled state, an operative connection, i.e. a torque-transmitting connection between two components, is released, so that no torque is transmitted. This is to be understood as "decoupling the operative connection between the drive unit of the motor vehicle and the output."It is conceivable to provide a position sensor on the coupling device in order to meet the high safety requirements. By reversing the direction of rotation of the first pump, the coupling device can be switched between the decoupled state, i.e. a "disconnect function", in which the drive device is decoupled from the output, and the coupled state or a "connect function", in which the drive device is coupled to the output. The coupling device can be advantageously used in electric axles with at least two electric motors as drive units, in which at least one of the electric motors drives a front axle, for example, and at least one other electric motor drives a rear axle, for example. The disconnect function allows the electric motor of one of the aforementioned axles to be decoupled from the output, while the other electric motor continues to transmit drive power to the wheels of the axle.This results in fuel consumption and range benefits. When the clutch is decoupled, drag torque loads can be reduced. When the clutch is engaged or engaged, the electric motor, which is connected to the output via the clutch, acts at least indirectly on the wheels connected to it.

[0010] The disconnect function with the clutch in the open state is sufficient for most operating situations, especially when driving the vehicle within the city at limited speeds. The coupled state of the clutch, on the other hand, is advantageous in acceleration situations, when driving uphill, or at higher speeds.

[0011] According to one embodiment, the clutch device is an electromechanically actuated DCU consisting of an electric motor that translates torque with the aid of a gear and, for example, a rack and pinion drive into a translational movement of a switching piston, wherein the switching piston switches the clutch device into the decoupled state or the coupled state depending on its position. In this sense, it is advantageous if the clutch device is or comprises a claw clutch. The switching element of the clutch device can be connected to a claw of the claw clutch in order to actuate it. The flow direction valve is configured to always forward fluid from the storage device to the first pump, regardless of the direction of rotation, i.e., the delivery direction of the first pump. The flow direction valve is actuated by the pump pressure level of the first pump.If the first pump is driven in the first direction of rotation, the flow direction valve is switched to the first switching state, so that the first volume flow of the first pump switches the coupling device to the decoupled state and simultaneously cools or lubricates the thermal consumers. If the first pump is driven in the second direction of rotation, the flow direction valve is switched to the second switching state, so that the second volume flow of the first pump switches the coupling device to the coupled state and simultaneously cools or lubricates the thermal consumers.

[0012] The flow direction valve can be connected via a first line section to a first intake or inlet side of the first pump in order to be able to draw in fluid from the storage device via the flow direction valve. Furthermore, the flow direction valve can be connected via a second line section to a second intake or inlet side of the first pump in order to be able to draw in fluid from the storage device via the flow direction valve. The first intake or inlet side of the first pump in the first switching state of the flow direction valve can be the outlet side of the first pump in the second switching state of the flow direction valve, and vice versa.

[0013] Thermal consumers are understood to be components of the motor vehicle's drive system that require cooling and / or lubrication. The fluid reaches the thermal consumers via distribution points. These are preferably passive components, in particular splash guards, which can be hydraulically connected in series and / or parallel. It is also conceivable for switchable hydraulic components, e.g. plate valves, to be supplied with coolant or lubricant, thereby allowing prioritization of coolant or lubricant branches and / or individual thermal consumers. If the drive system comprises an electric machine, a winding head or a stator winding, for example, can be cooled using fluid from the first or second volume flow. A bearing of rotatable components of the electric machine and / or an optional gearbox of the drive system can be lubricated using the same fluid.Gears can also be supplied with coolant or lubricant by the aforementioned fluid. An internal combustion engine, a clutch, or another element of the drive system can also be cooled and / or lubricated using the provided fluid. These and other components mentioned below are to be understood as thermal consumers within the meaning of the invention.

[0014] Using thermal models of the individual components, a respective temperature curve can be calculated depending on the load, allowing the total flow rate of the first pump to be adjusted as needed. Temperature sensors can also be installed on one or more components of the drive system, which can be used to regulate the cooling or lubricant requirements.

[0015] In one embodiment, the hydraulic system according to the invention can be designed as a wet sump system. In a wet sump design of the hydraulic system, the first pump, which in this embodiment is also understood as a lubricating oil pump, is connected via the flow direction valve to the reservoir device, which in this case is designed as a wet sump. Depending on the direction of rotation of the first pump, fluid is sucked from the reservoir device by the first pump via the flow direction valve.

[0016] The flow direction valve comprises a switching piston or a valve spool that can be switched between the first and second switching states. One side of the switching piston is therefore always subject to fluid pressure, while the other side of the switching piston is subject to the suction pressure of the first pump. The flow direction valve has several pockets that, depending on the switching state of the flow direction valve, can fluidically connect the supply device to the first pump or fluidically connect the first pump to the thermal consumers and the coupling device.

[0017] In the first switching state, the flow direction valve preferably forms a first pocket which fluidically connects the first volume flow of the first pump to the thermal consumers. At the same time, the first pump or the first volume flow of the first pump is fluidly connected, preferably directly, to the coupling device and generates a first pressure on one side of the switching piston of the coupling device in order to switch this to the decoupled state or to hold it in the decoupled state. Thus, a first part of the first volume flow is guided to the coupling device. At the same time, a second part, in particular the remaining part of the first volume flow in the first switching state of the flow direction valve is guided at least indirectly through the first pocket of the flow direction valve to the thermal consumers in order to cool or lubricate them.

[0018] In the second switching state, the flow direction valve preferably forms a second pocket which fluidically connects the second volume flow of the first pump to the thermal consumers. At the same time, the first pump or the second volume flow of the first pump is fluidly connected, preferably directly, to the coupling device and generates a second pressure on an opposite side of the switching piston in order to switch the latter into the coupled state or to hold it in the coupled state. Thus, a first part of the second volume flow is guided to the coupling device. At the same time, a second, in particular the remaining part of the second volume flow, is guided in the second switching state of the flow direction valve through the second pocket of the flow direction valve at least indirectly to the thermal consumers in order to cool or lubricate them.The first and second pressures of the first pump can be directed in opposite directions. The switching piston of the clutch device is held in its position by the hydraulic residual pressure level of the first or second volume flow. Furthermore, the flow direction valve preferably forms at least one third pocket in the first switching state, which fluidically connects the first pump to the storage device. In the first switching state of the flow direction valve, the third pocket ensures that fluid reaches the first intake side of the first pump, while at the same time the first volume flow of the first pump can be conveyed through the first pocket of the flow direction valve to the clutch device and to the thermal consumers.

[0019] In addition, in the second switching state, the flow direction valve forms at least a fourth pocket that fluidically connects the first pump to the storage device. In the second switching state of the flow direction valve, the fourth pocket ensures that fluid flows from the storage device to the second intake side of the first pump, while simultaneously allowing the second volume flow of the first pump to be conveyed through the second pocket of the flow direction valve to the coupling device and to the thermal consumers.

[0020] In this sense, in the first switching state of the flow direction valve, both the first and third pockets are open or are flowing with fluid, while the second and fourth pockets are closed or are not flowing with fluid. Similarly, in the second switching state of the flow direction valve, both the second and fourth pockets are open or are flowing with fluid, while the first and third pockets are closed or are not flowing with fluid.

[0021] The system preferably comprises a pressure control valve arranged in the fluid flow between the flow direction valve and the thermal consumers. The pressure control valve is designed to set a desired pressure level between the pump outlet and the thermal consumers. The pressure control valve is actively controllable. Using the pressure control valve, the pressure level in the pump pressure line can be adjusted strategically, i.e., in particular, at any time. During stationary operation, the pressure control valve can be switched off so that it cannot generate a pressure increase in the pump pressure line. This allows the coolant or lubricant to be supplied at the same pressure levels and with the same hydraulic efficiency, analogous to conventional hydraulic systems in which coupling devices are controlled or actuated separately.

[0022] At the hydraulic interfaces to the coupling device, both the pressure level and the flow level can be freely adjusted, i.e., in particular, at any time. This allows a high adjustment speed, i.e., a high pump flow rate, to be achieved with low pressure levels at the same time. This has a beneficial effect on the acoustics of the system, particularly when a claw clutch has a tooth-on-tooth position of the claw pistons. Likewise, a high adjustment speed, i.e., a high pump flow rate, can be achieved with high pressure levels at the same time. This allows "post-pressing", particularly when the tooth-on-tooth position is released in a claw clutch. Furthermore, a low adjustment speed, i.e., a low pump flow rate, can be achieved with high pressure levels at the same time, for example.to detect the position of a switching claw of a clutch device designed as a claw clutch.

[0023] In an alternative embodiment of the hydraulic system, the system according to the invention can also be designed as a dry sump system. First of all, everything stated above also applies to a dry sump system within the meaning of the invention. Dry sump systems generally have at least one suction point, preferably two or more suction points, which, in the form of a dry sump pump, pumps the coolant or lubricant from a suction position, in particular a sump, into the storage device of the first pump. The storage device of the first pump is also referred to in this case as a "bunker" or "reservoir". The volume flow between the at least one dry sump pump and the storage device corresponds, on average over time, to the lubricating oil flow, i.e., the first or second volume flow of the first pump.

[0024] Compared to the first pump, i.e. the lubricant pump, the dry sump pump has a significantly larger volumetric design, especially when two or more dry sump pumps are provided. In this sense, the system further comprises at least one second pump which, depending on its direction of rotation, is configured to convey either a third volume flow of fluid or a fourth volume flow of fluid from a sump into the storage device. The second pump is to be understood as a dry sump pump as described above. It is also conceivable to provide two or more second pumps or dry sump pumps, each conveying fluid in separate suction lines from the sump into the storage device. The second pump can be designed in the form of a double-stroke vane pump.The rear vane pressures of the vane pump can be supplied by the pressure level of the first pump, since the first pump can achieve a significantly higher pressure level.

[0025] Preferably, the first and at least the second pump are arranged on a common shaft, wherein the system further comprises a directional valve that is fluidically arranged between the sump and the storage device and that, depending on the direction of rotation of the first pump, can be switched either by the first volume flow into a first switching state or by the second volume flow into a second switching state in order to convey either the third volume flow of fluid or the fourth volume flow of fluid from the sump into the storage device. By arranging the first and second pumps on a common drive shaft, the manufacturing costs for the hydraulic system can be reduced.

[0026] The directional valve is arranged and configured to also reverse the delivery direction of the second pump or of further dry sump pumps arranged on the same shaft, regardless of the direction of rotation of the first pump, in particular when the direction of rotation of the first and second pumps is reversed. This ensures that, regardless of the direction of rotation of the first and second pumps, fluid is always pumped from the sump into the storage device, thus ensuring that the first pump is supplied. If a plurality of dry sump pumps are provided, every second pump has an associated directional valve. In the first switching state, the directional valve preferably forms a first pocket which fluidically connects the third volume flow of the at least second pump to the storage device.Preferably, in the second switching state, the directional valve forms a second pocket which fluidically connects the fourth volume flow of the at least second pump to the storage device.

[0027] In the first switching state of the directional valve, the second pocket of the directional valve is preferably provided to fluidically connect the second pump to the sump. Accordingly, the second pump draws fluid from the sump via the second pocket of the directional valve and conveys the fluid into the storage device via the first pocket of the directional valve. Conversely, in the second switching state of the directional valve, the first pocket of the directional valve is provided to fluidically connect the second pump to the sump, wherein the second pump draws fluid from the sump via the first pocket of the directional valve and then conveys this fluid into the storage device via the second pocket of the directional valve.

[0028] The directional valve preferably has a third pocket which, when the first pump rotates in the first direction of rotation, i.e. when the flow direction valve is in the first switching state, is filled with fluid of the first volume flow of the first pump in order to switch a switching piston or valve spool of the directional valve to the first switching state or to hold it in the first switching state. A fourth pocket is provided on the directional valve which, when the first pump rotates in the second direction of rotation, i.e. when the flow direction valve is in the second switching state, is filled with fluid of the second volume flow of the first pump in order to switch the switching piston or valve spool of the directional valve in the opposite direction, i.e. to the second switching state, or to hold it in the second switching state.

[0029] The required additional circuit, comprising the flow direction valve and optionally the pressure valve and / or the directional valve, can be integrated directly into a pump housing of the system. In this sense, at least the flow direction valve is integrated into a pump housing, at least including the first pump. If a pressure control valve is provided, the pressure control valve can also be arranged in the pump housing. If a directional valve is provided, the directional valve can also be arranged in the pump housing.

[0030] Alternatively, an additional adapter plate can be provided which comprises the flow direction valve and optionally the pressure valve and / or the directional valve. In this sense, the flow direction valve is arranged in a separate adapter part which can be connected to a pump housing, at least comprising the first pump. The adapter plate can be a retrofit component that can be subsequently connected to an existing hydraulic system and, in particular, can be fluidically connected to the first pump. For this purpose, the adapter plate and the existing hydraulic system have corresponding interfaces for connection or decoupling. Accordingly, corresponding line topologies between the suction and pressure connections are provided in the adapter plate. In this case, the same (first) pump can be used for both an e-axle with a disconnect unit and an e-axle without a disconnect unit.If a pressure control valve is provided, the pressure control valve can also be located in the adapter plate. If a directional valve is provided, the directional valve can also be located in the adapter plate.

[0031] The system preferably comprises a pressure filter arranged downstream of the first pump. In particular, the pressure filter can be arranged downstream of the flow direction valve. If a pressure control valve is provided, the pressure filter is preferably arranged downstream of the pressure control valve.

[0032] According to one embodiment, the hydraulic system further comprises a heat exchanger arranged downstream of the first pump. If a pressure control valve is provided, the heat exchanger is arranged downstream of the pressure control valve. If a pressure filter is provided, the heat exchanger is arranged upstream of the pressure filter, or the pressure filter is arranged downstream of the heat exchanger. The heat exchanger is configured to cool the fluid of the first or second volume flow flowing through it. The coolant or lubricant cooled by the heat exchanger is then directed to the thermal consumers.

[0033] According to a further aspect of the present invention, a drive device for a motor vehicle comprises a hydraulic system as described herein. The drive device can in particular comprise or be an electric drive axle, also called an E-axle. The electric drive axle can comprise an electric machine and an optional transmission in order to provide a torque and a speed for driving a drive wheel of the motor vehicle. In addition to the electric machine, an electric control device can also be included, which in one embodiment can also be cooled by means of fluid from the hydraulic system. The electric machine is supplied with electrical energy from an energy storage device.

[0034] According to yet another aspect of the present invention, a motor vehicle comprises a drive device as described herein. The motor vehicle can, in particular, comprise a motorcycle, a passenger car, a truck, or a bus. The motor vehicle comprises at least two axles. Preferably, two axles are provided, each axle being an electric drive axle and being drivable by at least one electric motor. At least one of these axles has a drive device within the meaning of the invention with a hydraulic system according to the invention in order to be able to implement a disconnect function by appropriate actuation of the first pump, in which the respective axle, or the wheels of this axle, run along undriven, while the motor vehicle continues to be driven via the other axle.

[0035] The invention will now be described in more detail with reference to the accompanying figures, in which:

[0036] Figure 1 shows a drive device in a motor vehicle with a hydraulic system according to the invention according to a first embodiment;

[0037] Figure 2a shows the hydraulic system according to the invention shown in Figure 1 in a disconnect state; Figure 2b shows the hydraulic system according to the invention of the motor vehicle shown in Figure 1 and Figure 2a in a connect state;

[0038] Figure 3a shows a hydraulic system according to the invention according to a second embodiment in a disconnect state; and

[0039] Figure 3b shows the hydraulic system according to the invention of the motor vehicle according to Figure 3a in a connect state.

[0040] Figure 1 shows a drive device 100 according to the invention on a front axle of a motor vehicle 105 according to the invention. The drive device 100 is configured to drive a drive wheel 110 of the motor vehicle 105. For this purpose, a drive unit 115 designed as an electric machine can be provided, which can be operated by means of a power converter 120 from an electrical energy storage device 125. While the power converter 120 can be included in the drive device 100, the energy storage device 125 is usually part of the motor vehicle 105. A transmission 130 can also be provided to convert mechanical energy to the drive wheel 110. Optionally, the transmission 130 is configured to be driven by a further drive machine (not shown), for example a reciprocating piston engine. Furthermore, a differential (not shown here) can be provided to transmit the drive power to both drive wheels 110 of the front axle.An identical drive device 100 can be operatively arranged on the rear axle of the motor vehicle 105 (not shown here) to drive the drive wheel 110 or, if a differential is provided, both drive wheels 110 of the rear axle. Thus, the motor vehicle 105 has at least two axles, with a drive device 100 according to the invention being operatively arranged on each axle. Each drive device 100 has a hydraulic system 135 according to the invention. The hydraulic system 135 of the front axle is described in more detail below, with the statements below analogously applying and being applicable to the hydraulic system 135 of the rear axle. The hydraulic system 135 is configured to supply one or more components of the drive device 100 and, optionally, one or more further components of the motor vehicle 105 with fluid in order to cool and / or lubricate the components.In addition, the hydraulic system 135 is configured to actuate a clutch device 140 of the drive device 100. The clutch device 140 is configured, depending on the switching state, to create or decouple an operative connection between the drive unit 115 and the transmission 130. If an operative connection exists, this is referred to below as the "connect function," in which drive power from the drive unit 115 is transmitted to the drive wheels 110. If there is no operative connection, this is referred to below as the "disconnect function," in which the drive power from the drive unit 115 cannot be transmitted to the drive wheels 110, wherein the drive unit 115 can optionally be switched off or deactivated.

[0041] The clutch device 140 is arranged here, for example, between the drive unit 115 and the transmission 130. However, it can in principle be arranged at any position in the power flow between the drive unit 115 and the drive wheels 110. In this case, the clutch device 140 is a positive-locking clutch, for example, a claw clutch.

[0042] In the following, it is assumed that an oil is used as the fluid for cooling and lubrication. For example, the fluid can be used to lubricate the electric machine 115 and the transmission 130, and also to cool the electric machine 115 and the power converter 120.

[0043] According to Figures 2a to 3b, the hydraulic system 135 comprises a first pump 205 in the form of a lubricating oil pump, a storage device 210 and a flow direction valve 215. Interfaces S1 to S5 and S2 to S7 are shown at various points of the hydraulic system 135 for textual reference only.

[0044] The first pump 205 is configured to be driven by an electric motor 220. To facilitate understanding of the invention, it can initially be assumed that a rotational speed of the electric motor 220 is constant. The first pump 205 can be driven in two directions of rotation, wherein, depending on the direction of rotation, either a first volume flow of fluid or a second volume flow of fluid is provided to supply a plurality of thermal consumers 225, which may in particular be included in the drive device 100.

[0045] The flow direction valve 215 is fluidically arranged between the storage device 210 and the first pump 205 and can be switched, depending on the direction of rotation of the first pump 205, either by the first volume flow of the first pump 205 into a first switching state or by the second volume flow of the first pump 205 into a second switching state.

[0046] The clutch device 140 is switched to a decoupled state in the first switching state of the flow direction valve 215 and to a coupled state in the second switching state of the flow direction valve 215. In the decoupled state, the drive unit 115 is decoupled from the output, i.e., the clutch is open and does not transmit any torque. In the coupled state, the drive unit 115 is coupled to the output, i.e., the clutch is closed and transmits torque between two components.

[0047] According to Figures 2a and 2b, a wet sump system is illustrated as an example of the first embodiment of the hydraulic system 135. Accordingly, fluid draining from the thermal consumers 225 collects in the reservoir 210, which is configured here as a wet sump. The reservoir 210, in turn, supplies the first pump 205 with fluid via the flow direction valve 215.

[0048] To cool or lubricate the thermal consumers 225, the fluid is sucked from the storage device 210 through a suction filter 230 and supplied to the first pump 205 via the flow direction valve 215. The first pump 205 is in turn fluidly connected to the thermal consumers 225, with the fluid flowing via the interface S2, first through a pressure control valve 235, then via the interface S3 through a heat exchanger 240 and an optional pressure filter 245 before being distributed to the thermal consumers 225. The pressure control valve 235 is arranged in the fluid flow between the flow direction valve 215 and the heat exchanger 240, with the heat exchanger 240 being arranged between the pressure control valve 235 and the pressure filter 245.

[0049] A temperature sensor 250 for sensing the fluid temperature can optionally be arranged downstream of the pressure filter 245. Splash orifices X01 to X12 can be provided as passive components connected in parallel on the thermal consumers 225. Splash orifices X01 to X12 can be used, for example, to provide stator and rotor cooling for the drive unit 115, gear lubrication, bearing lubrication, or the like.

[0050] The actively controllable pressure control valve 235, which is located between the flow at the pump outlet at interface S2 and the connection of the lubricating oil lines at interface S3, is designed to adjust the pressure level in the pump pressure line as desired, particularly according to the strategy. During steady-state operation, the pressure control valve 235 can be switched off or deactivated to prevent a pressure increase in the pump pressure line.

[0051] According to Figures 2a and 2b, the first pump 205 is fluidically connected to the reservoir device 210 via the flow direction valve 215. The flow direction valve 215 comprises a switching piston 255 that can be switched between a first switching state and a second switching state, wherein the switching piston 255 can be switched between the first and second switching states depending on the direction of rotation of the first pump 205.

[0052] When the first pump 205 is driven in the first direction of rotation, a first volume flow in a first conveying direction is generated, which switches the switching piston 255 of the flow direction valve 215 to the first switching state, which is shown in Figure 2a. In the first switching state of the flow direction valve 215, the fluid is sucked in by the first pump 205 via the pocket 1.3 / 1.4, which fluidically connects the first pump 205 to the storage device 255. At the same time, by actuating the switching piston 255 to the first switching state, a further pocket 1.5 is formed, which fluidically connects the first volume flow of the first pump 205 to the thermal consumers 225 in accordance with the above explanations. The coupling device 140, which comprises a switching element 260 that can be switched between a coupled state and a decoupled state, is also actuated via the first volume flow.According to Figure 2a, the switching element 260 is actuated upwards by the first volume flow into a first end position, which corresponds to the decoupled state in which a disconnect function is realized.

[0053] Figure 2b shows a connect function in which the drive unit 115 is coupled to an output. The connect function is implemented by reversing the direction of rotation of the first pump 205. When the first pump 205 is driven in the opposite second direction of rotation, a second volume flow in a second conveying direction is generated, which switches the switching piston 255 of the flow direction valve 215 to the second switching state according to Figure 2b. In the second switching state of the flow direction valve 215, the fluid is sucked in by the first pump 205 via the pocket 1.3 / 1.2, which fluidically connects the first pump 205 to the storage device 255. At the same time, by actuating the switching piston 255 to the second switching state, a further pocket 1.1 is formed, which fluidically connects the second volume flow of the first pump 205 to the thermal consumers 225 according to the above explanations.The second volume flow also actuates the switching element 260 of the coupling device 140 downwards into the second end position, which corresponds to the coupled state.

[0054] What becomes clear from the representation of the hydraulic system in Figures 2a and 2b is that, regardless of the direction of rotation of the first pump 205, due to the respective volume flow generated, one side of the switching piston 255 of the flow direction valve 215 is always subjected to the lubricating oil pressure of the first pump 205, and the opposite side of the switching piston 255 is always subjected to the suction pressure of the first pump 205. Thus, when the direction of rotation of the first pump 205 is reversed, the pressure levels on the side surfaces of the flow direction valve 215 are reversed, and the switching piston 255 changes its axial position. The switching element 260 of the coupling device 140 is held in its position by the residual hydraulic pressure level of the first or second volume flow. Therefore, no end position locking is required in the respective end position.

[0055] The pressure level for supplying the thermal consumers 225 can be freely specified by the pressure control valve 235. The required flow rate for the switching speed of the switching element 260 can be adjusted via the speed of the first pump 205.

[0056] With such a hydraulic system 135, the supply of lubricating oil to the thermal consumers 225 is ensured regardless of the direction of rotation of the first pump 205.

[0057] According to Figures 3a and 3b, a dry sump system is illustrated as a second exemplary embodiment of a hydraulic system 135 in the sense of the invention. Accordingly, in addition to the elements of the first exemplary embodiment, the system 135 further comprises a second pump 305, which is designed as a dry sump pump and can also be driven in two directions of rotation. The dry sump system thus has only a single suction point. According to this exemplary embodiment, the first and at least the second pump 205, 305 are arranged on a common shaft 310, with the electric motor 220 being arranged between the first and second pumps 205, 305 in a drive-effective manner. Thus, both pumps 205, 305 are arranged on a common motor shaft, which is particularly cost-effective.Depending on the direction of rotation of the first or second pump 205, 305, the second pump 305 can generate either a third volume flow of fluid in a first conveying direction or a fourth volume flow of fluid in a second conveying direction in order to convey fluid from a sump 315, which is designed here as a dry sump, via a filter 330 into the storage device 210, regardless of the direction of rotation of the second pump 305, from which the first pump 205 is fed, analogously to the previous exemplary embodiment. This oil flow is to be understood as a bilge oil flow. The storage device 210 is to be understood here as an oil bunker or reservoir and the second pump is to be understood as a bilge pump. Fluid flows from the thermal consumers 225 into the sump 315, which in turn feeds the storage device 210.

[0058] The bilge oil flow from the interfaces S4 and S5 to the storage device 210 corresponds, on average over time, to the lubricating oil flow from the interface S1 to the interface S2 of the first pump 205. The second pump 305 has a larger volumetric design than the lubricating oil pump, in particular if more than one dry sump or bilge pump is provided.

[0059] Furthermore, a directional valve 320 is provided, which is fluidically arranged between the sump 315 and the storage device 210 and which, depending on the direction of rotation of the first pump 205, can be switched either by the first volume flow of the first pump 205 into a first switching state or by the second volume flow of the first pump 205 into a second switching state in order to convey either the third volume flow of fluid or the fourth volume flow of fluid from the sump 315 into the storage device 210. Thus, the directional valve 320 is switched to the respective switching state depending on the direction of rotation of the first pump 205. The directional valve 320 is therefore controlled by the pressure levels of the first pump 205, and not by the pressure levels of the second pump 305.With the aid of the directional valve 320, the second pump 305 sucks fluid via the suction point S6, regardless of its direction of rotation and the direction of rotation of the first pump 205, and delivers this fluid to the storage device 210 via the interface S7.

[0060] When the first pump 205 is driven in the first direction of rotation, a first volume flow of the first pump 205 is generated in a first conveying direction, which fills a pocket 2.5 of the directional valve 320 with fluid and thereby moves or switches a switching piston 325 of the directional valve 320 upwards into the first switching state according to Figure 3a or holds it in the first switching state. In the first switching state of the directional valve 320, the fluid is sucked in by the second pump 305 via the pocket 2.3 / 2.4, which fluidically connects the second pump 305 to the sump 315. At the same time, the directional valve 320 forms a further pocket 2.1 / 2.2, which fluidically connects the third volume flow of the second pump 305 to the storage device 210.Furthermore, reference is made to what has been said with regard to Figure 2a, in particular with regard to the disconnect function, the supply of the thermal consumers 225 and the switching of the coupling device 140 into the decoupled state.

[0061] Figure 3b shows, in accordance with the explanations for Figure 2b, a connect function in which the drive unit 115 is coupled to an output. The connect function is implemented by reversing the direction of rotation of the first pump 205. When the first pump 205 is driven in the second direction of rotation, a second volume flow of the first pump 205 is generated in a second conveying direction, which fills a pocket 2.1 of the directional valve 320 with fluid and thereby moves or switches the switching piston 325 of the directional valve 320 downwards into the second switching state according to Figure 3b or holds it in the second switching state. By reversing the direction of rotation, both the directional valve 320 and the flow direction valve 215, in particular their switching pistons, change their end stops. It is conceivable, for example, toto open the pressure control valve 235 to the maximum and thereby reduce the pressure level so that the acoustic properties are improved when the direction of rotation is reversed.

[0062] In the second switching state of the directional valve 320, the fluid is sucked in by the second pump 305 via the pocket 2.2 / 2.3, which fluidically connects the second pump 305 to the sump 315. At the same time, the directional valve 320 forms a further pocket 2.4 / 2.5, which fluidically connects the fourth volume flow of the second pump 305 to the storage device 210. Furthermore, reference is made to what has been said regarding Figure 2b, particularly with regard to the connect function, the supply of the thermal consumers 225, and the switching of the coupling device 140 to the coupled state.

[0063] Such a hydraulic system 135 ensures that the reservoir 210 is filled and that the thermal consumers 225 are supplied with coolant or lubricant, regardless of the direction of rotation of the first pump 205 and the second pump 305. It is also conceivable to provide more than one dry sump pump or second pump 305. In this case, the dry sump pumps are connected in parallel. This allows the dry sump pumps to be designed more slenderly. With multiple second pumps 305, each dry sump pump has an associated directional valve 320 in order to always pump fluid from the sump 310 into the reservoir 210, regardless of the direction of rotation of the first pump 205 and the respective second pump 305.

[0064] What is only indicated in Figure 2b, but equally applies to all figures and exemplary embodiments, is that the flow direction valve 215, the pressure control valve 235, and, if provided and present, the directional valve 320 can be integrated into a common pump housing, in which the electric motor 220 and the first pump 205 are also arranged. The pump housing is indicated here in a highly simplified manner by a first dashed line 290.

[0065] In an alternative embodiment of the hydraulic system, at least the flow direction valve 215, the pressure control valve 235, and, if provided and present, the directional valve 320 can be arranged in a separate adapter part, which can be connected to a pump housing—not shown in detail here—via a corresponding interface. The adapter part is indicated here in a highly simplified manner by a second dashed line 295 as an alternative solution for integrating the valves in the pump housing. Figure 2b shows that the electric motor 220 and the first pump 205 are located outside the second dashed line 295.

[0066] Reference symbol

[0067] drive device

[0068] Motor vehicle

[0069] drive wheel

[0070] drive unit

[0071] Power converter electrical energy storage

[0072] Transmission hydraulic system

[0073] Coupling device first pump

[0074] Storage facility

[0075] Flow direction valve

[0076] Electric motor thermal consumers

[0077] suction filter

[0078] pressure control valve

[0079] heat exchanger

[0080] pressure filter

[0081] Temperature sensor

[0082] Switching piston of the flow direction valve

[0083] Switching element of the clutch device first dashed line second dashed line second pump

[0084] Wave

[0085] swamp

[0086] Directional valve

[0087] Switching piston of the directional valve 330 Filter

[0088] 1.1... 1.5 Pocket of the flow direction valve

[0089] 2.1 ...2.5 Directional valve pocket

[0090] 51...57 interface

[0091] X01 ... X12 splash guard

Claims

Patent claims 1. A hydraulic system (135) for cooling or lubricating thermal consumers (225) and for actuating a clutch device (140) of a motor vehicle (105), the system (135) comprising the following elements: a first pump (205) configured to provide a first or second volume flow of fluid depending on its direction of rotation; a clutch device (140) for generating or decoupling an operative connection between a drive unit (115) of the motor vehicle (105) and an output;and a flow direction valve (215) which is fluidically arranged between a storage device (210) and the first pump (205) and which, depending on the direction of rotation of the first pump (205), can be switched either by the first volume flow into a first switching state or by the second volume flow into a second switching state, wherein the coupling device (140) is switched to a decoupled state in the first switching state of the flow direction valve (215) and is switched to a coupled state in the second switching state of the flow direction valve (215); 2. System (135) according to claim 1, further comprising at least one second pump (215) which is configured to convey, depending on its direction of rotation, either a third volume flow of fluid or a fourth volume flow of fluid from a sump (315) into the storage device (210).

3. System (135) according to claim 2, wherein the first and at least the second pump (205, 215) are arranged on a common shaft (310), wherein the system (135) further comprises a directional valve (320) which is fluidically arranged between the sump (315) and the storage device (210) and which, depending on the direction of rotation of the first pump (205), can be switched either by the first volume flow into a first switching state or by the second volume flow into a second switching state in order to convey either the third volume flow of fluid or the fourth volume flow of fluid from the sump (315) into the storage device (210).

4. System (135) according to claim 3, wherein the directional valve (320) in the first switching state forms a first pocket (2.1, 2.2) which fluidically connects the third volume flow of the at least second pump (215) to the storage device (255).

5. System (135) according to claim 3 or claim 4, wherein the directional valve (320) in the second switching state forms a second pocket (2.4, 2.5) which fluidically connects the fourth volume flow of the at least second pump (215) to the storage device (255).

6. System (135) according to one of the preceding claims, wherein the flow direction valve (215) in the first switching state forms a first pocket (1.5) which fluidically connects the first volume flow of the first pump (205) to the thermal consumers (225).

7. System (135) according to one of the preceding claims, wherein the flow direction valve (215) in the second switching state forms a second pocket (1.1) which fluidically connects the second volume flow of the first pump (205) to the thermal consumers (225).

8. System (135) according to one of the preceding claims, wherein the flow direction valve (215) in the first switching state forms at least one third pocket (1.2, 1.3) which fluidically connects the first pump (205) to the storage device (255).

9. System (135) according to one of the preceding claims, wherein the flow direction valve (215) in the second switching state forms at least one fourth pocket (1.4) which fluidically connects the first pump (205) to the storage device (255).

10. System (135) according to one of the preceding claims, further comprising a pressure control valve (235) arranged in the fluid flow between the flow direction valve (215) and the thermal consumers (225).

11. System (135) according to one of the preceding claims, wherein the flow direction valve (215) is integrated in a pump housing, at least comprising the first pump (205).

12. System (135) according to one of claims 1 to 10, wherein the flow direction valve (215) is arranged in a separate adapter part which can be connected to a pump housing, at least comprising the first pump (205).

13. The system (135) of any preceding claim, further comprising a heat exchanger (240) disposed downstream of the first pump (205).

14. Drive device (100) for a motor vehicle (105), comprising a hydraulic system (135) according to one of the preceding claims.

15. Motor vehicle (105) comprising a drive device (100) according to claim 14.

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