DE102021208238A1 - Hydraulic system for a motor vehicle - Google Patents

Abstract

The invention relates to a hydraulic system (1) for a motor vehicle, in particular for a hybrid motor vehicle, with at least one displacement pump (2), with a first consumer (3), with a second consumer (4), with at least one fluid reservoir (5) , wherein the positive displacement pump (2) has a first connection (2a) and a second connection (2b), wherein the positive displacement pump (2) has a shaft (2c) and wherein the shaft (2c) by means of a motor (7), in particular one Electric motor, is drivable.
A supply of the first and/or the second consumer (3, 4) with fluid (6) is improved in that a flow pump (8) is also present and/or provided, the flow pump (8) having a drive shaft (8a). , wherein the drive shaft (8a) of the flow pump (8) is and/or can be operatively coupled to the shaft (2c) of the positive displacement pump (2), the flow pump (8) having an inlet port (8b) and an outlet port (8c). , wherein when the positive displacement pump (2) is operated in the second direction of rotation of the flow pump (8), fluid (6) can then also be supplied from the fluid reservoir (5) via the inlet connection (8b), and wherein when the positive displacement pump (2) is operated in the second direction of rotation, the fluid (6) can be discharged from the flow pump (8) via the outlet connection (8c) and fed to the first consumer (3).

Description

The invention relates to a hydraulic system for a motor vehicle having the features of the preamble of patent claim 1.

Various types of hydraulic systems for motor vehicles are known in the prior art.

In the DE 10 2018 130 700 A1 a hydraulic system for a motor vehicle and an associated method for establishing a hydraulic readiness of this hydraulic system is shown. The hydraulic system has a pump designed as a reversible pump. The pump can be driven in a first direction of rotation by means of an electric motor. In the first direction of rotation, the pump delivers fluid to a first consumer, here to a cooling oil device. The pump can be driven in a second direction of rotation opposite to the first direction of rotation. In the second direction of rotation, the pump delivers the fluid to at least one second consumer for an actuation function. In the explicit exemplary embodiment shown here, the pump delivers the fluid to two second consumers, for example to a parking lock actuator and to a clutch. For this purpose, the hydraulic system has further elements such as several valves, in particular several non-return valves, a 4/2-way valve and a 2/2-way valve, a reservoir for providing the fluid and an intake line with a suction filter, with the fluid being drawn out by means of the intake line the reservoir can be directed towards the pump.

The DE 10 2018 112 663 A1 shows a hydraulic system with two different fluid reservoirs for supplying either a first consumer or a second consumer. The hydraulic system has a pump designed as a reversible pump. The pump is coupled on one side to a first consumer line designed as a coolant line and on the other side to a second consumer line designed as an actuating line. A first consumer or several first consumers are supplied via the first consumer line. The supply is for cooling and/or lubricating these first consumers. The first consumer can be a bearing, a heat exchanger and/or a cooler. A second consumer is supplied via the second consumer line. The supply takes place in order to carry out an actuation on the second consumer. The second consumer can be an actuator, such as a hydraulic actuator, a slave cylinder, in particular a clutch slave cylinder. There is a first fluid reservoir and a second fluid reservoir. The first fluid reservoir is provided for cooling/lubricating the respective components and is designed as a transmission sump (fluid below the pump), with the second fluid reservoir being provided for the actuator function.

In the DE 10 2018 112 670 A1 discloses a hydraulic system of a serial hybrid transmission with a parking lock function. The hydraulic system has a pump designed as a reversible pump, which can be connected to a first consumer line designed as a coolant line for supplying a first consumer. The first consumer is designed, for example, as a bearing, a cooler or a heat exchanger, and the first consumer can be supplied with a fluid designed as a hydraulic medium for its cooling and/or lubrication. On the other hand, the pump can be connected to a second consumer line designed as an activation line for supplying a second consumer with the same fluid to actuate it. The second consumer is, for example, an actuator or has several actuators, in particular the second consumer is designed as a slave cylinder, in particular in the manner of a CSC (“Concentric Slave Cylinder” or central slave cylinder). The second consumer acts on a separating clutch/clutch or the second consumer is designed as such a clutch, in particular as a K0 clutch. A switching valve is provided which specifically and selectively connects a pump outlet to the first consumer line or the second consumer line. For this purpose, the switching valve is controlled electrically by a control unit. The control unit also acts on an electric motor that operates the pump. A check valve is used both in the second consumer line and in an intake line. The first check valve is positioned to prevent fluid from flowing back through a suction filter to a fluid reservoir formed as a transmission sump. The second check valve is used in such a way that the fluid from the second consumer is prevented from running back through the switching valve. A drain valve / cut-off valve is hydraulically controlled and can allow a return flow away from the second consumer to the fluid reservoir. A connecting line designed as an activation line branch branches off from the second consumer line to supply a parking lock actuator. The parking lock actuator acts on a parking lock/parking lock mechanism.

The aforementioned hydraulic systems are not yet optimally designed and have the disadvantage that if the second consumer is supplied/acted with fluid by rotating the pump in the corresponding direction of rotation, the first consumer is then not supplied/acted with fluid. In the above examples there is therefore no cooling and/or lubrication of a gear or for the components of the gear possible if, for example, fluid is conveyed to the clutch by means of the pump. In this case, cooling/lubricating the transmission when the clutch is closed is only possible by means of additional valves, with such valves representing a corresponding cost factor for the hydraulic system. Furthermore, it is also disadvantageous in this case that the pressure at the clutch cannot be immediately corrected, ie in particular cannot be increased, while the fluid is being conveyed by means of the pump to the transmission. Under certain circumstances, this means that additional sensors are required to monitor the clutch pressure. Additional components such as valves and/or sensors can also include an undesirable potential for errors and failures, which in turn increases the control effort.

In the DE 10 2011 008 607 A1 Finally, there is another hydraulic system, shown here for a powershift transmission device. A first hydraulic circuit segment is fluidly connected to a first positive displacement hydraulic pumping element. The first positive displacement hydraulic pumping element is configured to deliver a relatively low pressure, high flow volume (hydraulic) fluid flow to the first hydraulic circuit segment. The first hydraulic circuit segment is designed to supply (hydraulic) fluid for cooling and lubricating a first consumer designed as a transmission and includes a lubricating circuit, an electric motor rotor cooling circuit and an electric motor stator cooling circuit. A second hydraulic circuit segment is fluidly connected to the second positive displacement hydraulic pumping element. The second positive displacement hydraulic pumping element is configured to provide a relatively high pressure, low flow volume fluid flow. The second hydraulic circuit segment is configured to supply fluid under pressure to a clutch activation circuit, including a second consumer embodied as at least one clutch, associated with the second hydraulic circuit segment, to selectively activate one or more torque-transmitting clutches using known control solenoid valves for transmission gear selection and control and to disable. Specifically, the first and second positive displacement hydraulic pumping elements are housed in a common housing and are driven using a single shaft. The positive displacement pumping elements are preferably embodied as a fixed displacement binary gear pump and/or a fixed displacement binary balanced vane pump.

The two hydraulic positive-displacement pump elements are driven in a specific direction of rotation, so that the supply to the two hydraulic circuit segments is correspondingly limited. A flexible control of the clutches is only possible by means of the additional and "expensive" or cost-intensive control solenoid valves.

The invention is therefore based on the object of designing and developing the hydraulic system for a motor vehicle mentioned at the outset in such a way that the supply of a first and/or a second consumer with fluid is improved, in particular the associated cost and/or control effort is reduced.

This above-mentioned object on which the invention is based is now initially achieved for the hydraulic system for a motor vehicle with the features of patent claim 1 .

The basic principle of the invention is essentially that a flow pump is now additionally present and/or provided. This flow pump has a drive shaft, the drive shaft of the flow pump being operatively coupled and/or capable of being operatively coupled to the shaft of the displacement pump. It is conceivable that the shaft and the drive shaft are connected to one another by means of a flange. It is also conceivable that the shaft and the drive shaft are coupled or can be coupled to one another by means of a shaft coupling. Furthermore, it is conceivable that the shaft and the drive shaft are designed as a single, integral component. The drive shaft could also be designed as a hollow shaft and be arranged partially around the shaft and then be coupled to the shaft in a rotationally active manner, in particular by means of conventional connections also referred to as shaft-hub connections.

The flow pump has an inlet port and an outlet port. When the positive displacement pump is operated in the second direction of rotation, the flow pump can then also be supplied with fluid from the fluid reservoir via the inlet connection, like the positive displacement pump. When the displacement pump is operated in the second direction of rotation, the fluid can be discharged from the flow pump via the outlet connection and fed to the first consumer.

In this way, a very good compromise is achieved with regard to the costs and/or the functionality of the hydraulic system, taking into account the supply of the first and the second consumer. When the positive displacement pump rotates in the second direction of rotation, a pressure of the fluid in the second consumer, in particular on the clutch, can be tracked as required during driving of the motor vehicle, in particular, with the first consumer also being involved is further supplied with fluid by means of the flow pump. In the usual operating conditions in the motor vehicle, in particular in a hybrid motor vehicle, this fluid flow generated by the flow pump to the first consumer is sufficient to also provide the first consumer with sufficient lubrication and/or cooling.

In the flow pump, in particular, an open space is formed between the inlet port and the outlet port. Energy is transferred from the flow pump to the fluid, for example, with the help of rotor blades, vanes or blades.

In the positive-displacement pump, the fluid is conveyed in particular through self-contained volumes formed in the positive-displacement pump. The fluid is conveyed by moving the volumes and/or by a reciprocal change in the size of the volumes.

The ratio of the delivery volumes of the positive displacement pump to the flow pump can be freely interpreted, so that with an appropriate design of this ratio, the engine can also be operated at an operating point with optimal efficiency in a large number of operating states of the motor vehicle.

Advantageously, when the displacement pump is operated in the first direction of rotation, fluid can then also be fed from the fluid reservoir to the first consumer by means of the flow pump. Both when the positive displacement pump is operated in the first direction of rotation and when the positive displacement pump is operated in the second direction of rotation, the fluid can thus be supplied to the first consumer by means of the flow pump.

On the one hand, it is conceivable that fluid is conveyed in the same way in both directions of rotation by means of the flow pump. On the other hand, the flow pump could also be designed such that the efficiency of the flow pump is greater in the first direction of rotation than in the second direction of rotation (or vice versa). With the same speed, a higher fluid pressure can be achieved at the outlet connection with higher efficiency. The efficiency of the flow pump can, for example, be influenced accordingly by appropriate configurations of the rotor blades, the vanes or the vanes.

In a preferred embodiment of the hydraulic system, a suction line is fluidly connected to the fluid reservoir and to an inlet of a first tee. A first connecting line is fluidly connected to an outlet of the first tee and to an inlet of a second tee. A second connecting line is fluidly connected to an outlet of the second tee and to an inlet of a third tee. A third connecting line is fluidly connected to a branch of the third tee and to the second connection of the positive displacement pump. A fourth connecting line is fluidly connected to the first connection of the positive displacement pump and to a branch of a fourth tee. A fifth connecting line is fluidly connected to a branch of the first tee and to an inlet of the fourth tee. A sixth connecting line is fluidly connected to an outlet of the fourth tee and to an inlet of a fifth tee. A first consumer line is fluidly connected to an outlet of the fifth tee and to the first consumer. A second consumer line is fluidly connected to an outlet of the third tee and to the second consumer. A seventh connection line is fluidly connected to a branch of the second tee and to the inlet port of the flow pump. An eighth connecting line is fluidly connected to the outlet port of the flow pump and to a branch of the fifth tee.

In this way, the required flows between the various components/elements of the hydraulic system can be implemented with minimal outlay on equipment, in particular with a particularly small number of connecting lines. The first, the second and the fifth connecting line ensure that the fluid from the fluid reservoir can be supplied both to the first connection of the displacement pump and to the second connection of the displacement pump.

The T-pieces are characterized in that they each have three connections, namely an inlet, an outlet and a branch. Typically, an axis of the branch is at an angle of 90° to an axis passing through both the inlet and outlet. Of course, other angles are also possible here. Furthermore, it is conceivable that an axis of the inlet does not coincide with the axis of the outlet, but that the axis of the inlet is arranged at an angle to the axis of the outlet. In particular, the components referred to here as "T-pieces" also mean or "include" those "components" which are sometimes also referred to as "Y-pieces" by the person skilled in the art or where the lines are effectively "T - and Y-wise". The designation inlet, outlet and branch, therefore says nothing about the direction in which the fluid flows through the inlet, the outlet or the branch. The fluid can flow into the respective T-piece via the inlet, the outlet or the branch, as well as flow out of the respective T-piece via the inlet, the outlet or the branch. Nevertheless, the designations are chosen so that the fluid then flows in via the inlet and out via the outlet in the usual operating states of the hydraulic system. This may be pointed out on this side.

A flow of the fluid from the fluid reservoir to the second connection of the positive displacement pump is advantageously made possible by means of a first check valve and a flow of the fluid from the second connection of the positive displacement pump to the fluid reservoir is avoided. This is particularly important when operating the positive displacement pump in the second direction of rotation when the fluid flows out of the second port. The first check valve then ensures that the fluid flows to the second consumer and does not flow back into the fluid reservoir.

Alternatively or additionally, a flow of the fluid from the fluid reservoir to the first connection of the positive displacement pump is enabled by means of a second check valve and a flow of the fluid from the first connection of the positive displacement pump to the fluid reservoir is avoided. This is particularly important when operating the positive displacement pump in the first direction of rotation when the fluid flows out of the first port. The second check valve then ensures that the fluid flows to the first consumer and does not flow back into the fluid reservoir.

Such check valves are simple in construction and, in particular, do not require any electronic control.

In a further embodiment of the hydraulic system, the first check valve is functionally operatively coupled to the second connecting line or functionally operatively arranged in the second connecting line in such a way that a flow of the fluid in the second connecting line from the outlet of the second T-piece to the inlet of the third Allows T-piece and a flow of fluid in the second connecting line from the inlet of the third T-piece to the outlet of the second T-piece is avoided.

Alternatively or additionally, the second check valve is operatively coupled to the fifth connection line or operatively arranged in the fifth connection line in such a way that a flow of the fluid in the fifth connection line from the branch of the first T-piece to the inlet of the fourth T-piece and a flow of the fluid in the fifth connecting line from the inlet of the fourth T-piece to the branch of the first T-piece is avoided.

Alternatively or additionally, a third check valve is operatively coupled to the sixth connection line or operatively arranged in the sixth connection line such that a flow of fluid in the sixth connection line from the outlet of the fourth tee to the inlet of the fifth tee allows and a flow of the fluid in the sixth connecting line from the inlet of the fifth T-piece to the outlet of the fourth T-piece is avoided.

This ensures that the fluid flows from the outlet port of the flow pump to the first consumer and does not flow (back) from the outlet port of the flow pump to the first port of the displacement pump or to the fluid reservoir.

Alternatively or additionally, a fourth check valve is functionally operatively coupled to the seventh connecting line or functionally operatively arranged in the seventh connecting line in such a way that a flow of the fluid in the seventh connecting line from the branch of the second T-piece to the inlet port of the flow pump is enabled and a Flow of the fluid is avoided in the seventh connecting line from the inlet port of the flow pump to the branch of the second T-piece.

The fourth check valve prevents the flow pump from being traversed in the opposite direction to the intended flow direction from the inlet port to the outlet port due to unfavorable pressure conditions in the hydraulic system.

The first consumer is preferably designed as a transmission for a motor vehicle or is provided in a transmission for a motor vehicle, so that at least one component, in particular a gear wheel, a bearing and/or a sliding sleeve of the transmission can be lubricated and/or cooled by means of the fluid .

In a particularly preferred embodiment of the hydraulic system, the second consumer is designed as a clutch of the motor vehicle, in particular as a K0 clutch of the hybrid vehicle. The clutch can be actuated by means of the fluid. When the positive displacement pump is operated in the second direction of rotation, a Pressure of the fluid at the clutch adjustable by means of a speed of the positive displacement pump. In particular, a specific pressure is set at the clutch, so that a specific torque can be transmitted by means of the clutch, or so that a specific, predetermined setpoint slip is set at the clutch. In particular, the clutch can be closed by applying pressure accordingly. Furthermore, in particular, when the displacement pump is operated in the first direction of rotation, the clutch is opened or can be opened.

Various operating modes of the hybrid vehicle can be implemented using the so-called K0 clutch of the hybrid vehicle. When the K0 clutch is open, purely electric driving or recuperation, in particular by means of a second electric machine of the hybrid vehicle, is made possible.

When the K0 clutch is disengaged, serial operation is also possible, in which an internal combustion engine of the hybrid vehicle drives a first electric machine of the hybrid vehicle, with the electrical energy generated by the first electric machine being transmitted to the second electric machine, with the motor vehicle then being driven by the second electric machine becomes.

When the K0 clutch is closed, parallel operation is possible, in which the motor vehicle is driven by means of the internal combustion engine and at least one of the two electric machines.

In a further possible embodiment of the hydraulic system, a valve arrangement, in particular a fifth check valve and a drain valve, is functionally operatively coupled to the second consumer line or arranged in such a functionally operative manner in the second consumer line that by means of the valve arrangement, in particular the fifth check valve, a flow of the Allows fluids in the second consumer line from the outlet of the third tee to the second consumer and prevents fluid in the second consumer line from flowing from the second consumer to the outlet of the third tee. Furthermore, the fluid can be drained from the second consumer by means of the valve arrangement, in particular the drain valve. In this way, the pressure of the fluid at the second consumer is no longer solely dependent on the speed and direction of rotation of the displacement pump, so that other control options for the second consumer are also made possible. In particular, if the second consumer is designed as a clutch, this clutch can be kept closed by means of the valve arrangement, even if the fluid is then supplied to the first consumer by means of the displacement pump.

The flow pump is preferably designed as a radial centrifugal pump. In such a radial centrifugal pump, the fluid flows essentially parallel to the drive shaft to an impeller of the radial centrifugal pump. By rotating the pump wheel, the fluid is accelerated by means of the pump wheel in such a way that the fluid flows out of the pump wheel essentially radially, ie perpendicularly to the drive shaft. Slight deviations in the direction of flow from this parallel or perpendicular orientation to the drive shaft are conceivable. Such a radial centrifugal pump makes it possible in a particularly simple manner for the fluid to flow from the inlet port to the outlet port in both directions of rotation of the drive shaft, or for it to be accelerated in both directions of rotation from the inlet port to the outlet port by means of the impeller. The impeller usually has a plurality of rotor blades, vanes or vanes aligned radially with respect to the drive shaft.

The displacement pump is preferably designed as a gear pump. Such gear pumps are easy to manufacture and are robust during operation. Furthermore, the dependency between the speed of the gear pump and the fluid pressure generated at this speed is known and can be set particularly precisely.

Alternatively, the displacement pump could also be designed as a rotary piston pump, in particular a Roots pump, as a rotary vane pump or as a vane pump, etc.

• 1 schematisch in Form eines Fließschemas ein bevorzugtes Ausführungsbeispiel eines erfindungsgemäßen Hydrauliksystems für ein Kraftfahrzeug.

There are now a large number of possibilities for designing and developing the hydraulic system for a motor vehicle in an advantageous manner. In this regard, reference may first be made to the patent claims subordinate to patent claim 1. A preferred embodiment of the hydraulic system for a motor vehicle is explained in more detail below with reference to the drawing and the associated description. In the drawing shows:

• 1 schematically in the form of a flow chart, a preferred embodiment of a hydraulic system according to the invention for a motor vehicle.

The hydraulic system 1 for a motor vehicle, in particular for a hybrid motor vehicle, which is not shown in detail here, has at least one displacement pump 2 . Furthermore, a first consumer 3, in particular a transmission part of the hydraulic system 1. A second consumer 4, esp a clutch in particular is also part of the hydraulic system 1.

The hydraulic system 1 has at least one fluid reservoir 5, in particular an oil sump of the transmission.

The displacement pump 2 has a first connection 2a and a second connection 2b.

When the positive displacement pump 2 is operated in a first direction of rotation, a fluid 6 can be supplied to the positive displacement pump 2 from the fluid reservoir 5 via the second connection 2b. When the positive displacement pump 2 is operated in the first direction of rotation, the fluid 6 can be discharged from the positive displacement pump 2 via the first connection 2a and fed to the first consumer 3 .

When the positive displacement pump 2 is operated - in a second direction of rotation opposite to the first direction of rotation, the fluid 6 can be supplied to the positive displacement pump 2 from the fluid reservoir 5 via the first connection 2a, with the fluid 6 being supplied via the second direction of rotation when the positive displacement pump 2 is operated in the second direction of rotation the second connection 2b can be removed from the displacement pump 2 and fed to the second consumer 4.

The positive displacement pump 2 has a shaft 2c. The shaft 2c can be driven by a motor 7, in particular an electric motor.

In addition, a flow pump 8 is present and/or provided.

The flow pump 8 has a drive shaft 8a. The drive shaft 8a of the flow pump 8 is operatively coupled to the shaft 2c of the displacement pump 2 and/or can be operatively coupled. The flow pump 8 has an inlet port 8b and an outlet port 8c. When the displacement pump 2 is operated in the second direction of rotation, the flow pump 8 can then also be supplied with fluid 6 from the fluid reservoir 5 via the inlet connection 8b. When the displacement pump 2 is operated in the second direction of rotation, the fluid 6 can be discharged from the flow pump 8 via the outlet connection 8c and fed to the first consumer 3 .

When the displacement pump 2 is operated in the first direction of rotation, the flow pump 8 can then also be used to supply fluid 6 from the fluid reservoir 5 to the first consumer 3 .

Depending on the design of the positive displacement pump 2 and the flow pump 8, the flows of the fluid 6 to the first and second consumer 3 or 4 can be precisely matched to one another depending on the speed and direction of rotation of the positive displacement pump 2 and the flow pump 8. When the shaft 2c and the drive shaft 8a are operatively coupled to each other, the speed and the direction of rotation of the positive displacement pump 2 and the flow pump 8 are directly dependent on each other.

A suction line 9 is fluidically connected to the fluid reservoir 5 and to an inlet 10a of a first T-piece 10 . A first connecting line 15.1 is fluidically connected to an outlet 10b of the first T-piece 10 and to an inlet 11a of a second T-piece 11. A second connecting line 15.2 is fluidically connected to an outlet 11b of the second T-piece 11 and to an inlet 12a of a third T-piece 12. A third connecting line 15.3 is fluidically connected to a branch 12c of the third T-piece 12 and to the second connection 2b of the displacement pump 2. A fourth connecting line 15.4 is fluidically connected to the first connection 2a of the displacement pump 2 and to a branch 13c of a fourth T-piece 13. A fifth connecting line 15.5 is fluidically connected to a branch 10c of the first T-piece 10 and to an inlet 13a of the fourth T-piece 13. A sixth connecting line 15.6 is fluidically connected to an outlet 13b of the fourth T-piece 13 and to an inlet 14a of a fifth T-piece 14. A first consumer line 16.1 is fluidically connected to an outlet 14b of the fifth T-piece 14 and to the first consumer 3. A second consumer line 16.2 is fluidically connected to an outlet 12b of the third T-piece 12 and to the second consumer 4. A seventh connecting line 15.7 is fluidically connected to a branch 11c of the second T-piece 11 and to the inlet connection 8b of the flow pump 8. An eighth connecting line 15.8 is fluidically connected to the outlet port 8c of the flow pump 8 and to a branch 14c of the fifth T-piece 14.

A first check valve 17.1 allows the fluid 6 to flow from the fluid reservoir 5 to the second connection 2b of the positive displacement pump 2 and prevents the fluid 6 from flowing from the second connection 2b of the positive displacement pump 2 to the fluid reservoir 5.

The first check valve 17.1 is then arranged in a functionally effective manner in a first connection path between the displacement pump 2 and the fluid reservoir 5. The first connection path has the intake line 9, the first T-piece 10, the first connecting line 15.1, the second T-piece 11, the second connecting line 15.2, the third T- Piece 12 and the third connecting line 15.3.

A second check valve 17.2 allows the fluid 6 to flow from the fluid reservoir 5 to the first connection 2a of the positive displacement pump 2 and prevents the fluid 6 from flowing from the first connection 2a of the positive displacement pump 2 to the fluid reservoir 5.

The second check valve 17.1 is then arranged in a functionally effective manner in a second connection path between the displacement pump 2 and the fluid reservoir 5. The second connection path has the intake line 9, the first T-piece 10, the fifth connecting line 15.5, the fourth T-piece 11 and the fourth connecting line 15.4.

The first check valve 17.1 is functionally operatively coupled to the second connecting line 15.2 or so functionally operatively arranged in the second connecting line 15.2 that a flow of the fluid 6 in the second connecting line 15.2 from the outlet 11b of the second T-piece 11 to the inlet 12a of the third T-piece 12 and a flow of the fluid 6 in the second connecting line 15.2 from the inlet 12a of the third T-piece 12 to the outlet 11b of the second T-piece 11 is avoided.

The second check valve 17.2 is functionally operatively coupled to the fifth connecting line 15.5 or so functionally operatively arranged in the fifth connecting line 15.5 that a flow of the fluid 6 in the fifth connecting line 15.5 from the branch 10c of the first T-piece 10 to the inlet 13a of the fourth T-piece 13 and a flow of the fluid 6 in the fifth connecting line 15.5 from the inlet 13a of the fourth T-piece 13 to the branch 10c of the first T-piece 10 is avoided.

A third check valve 17.3 is functionally operatively coupled to the sixth connecting line 15.6 or functionally operatively arranged in the sixth connecting line 15.6 such that a flow of the fluid 6 in the sixth connecting line 15.6 from the outlet 13b of the fourth T-piece 13 to the inlet 14a of the fifth T-piece 14 and a flow of the fluid 6 in the sixth connecting line 15.6 from the inlet 14a of the fifth T-piece 14 to the outlet 13b of the fourth T-piece 13 is avoided.

A fourth check valve 17.4 is functionally operatively coupled to the seventh connecting line 15.7 or functionally operatively arranged in the seventh connecting line 15.7 such that a flow of the fluid 6 in the seventh connecting line 15.7 from the branch 11c of the second T-piece 11 to the inlet port 8b of the flow pump 8 and a flow of the fluid 6 in the seventh connecting line 15.7 from the inlet connection 8b of the flow pump 8 to the branch 11c of the second T-piece 11 is avoided.

The flow through the third connecting line 15.3 and the fourth connecting line 15.4 depends on the direction of rotation of the positive displacement pump 2 in a different direction. All other connecting lines 15.1, 15.2, 15.5, 15.6, 15.7 and 15.8 are flown through in the same direction in both directions of rotation of the displacement pump 2.

The first consumer 3 is designed as a transmission for a motor vehicle or is provided in a transmission for a motor vehicle. At least one component, in particular a gearwheel, a bearing and/or a sliding sleeve, of the transmission can then be lubricated and/or cooled by means of the fluid 6 .

Such a transmission is in particular part of a drive train of the motor vehicle. If the motor vehicle is designed as a hybrid vehicle, the transmission also enables torque transmission between an internal combustion engine of the hybrid vehicle and a first and/or a second electric machine of the hybrid vehicle.

The second consumer 4 is designed as a clutch of the motor vehicle, in particular as a K0 clutch of the hybrid vehicle. The clutch can be actuated by means of the fluid 6, wherein when the positive displacement pump 2 is operated in the second direction of rotation, a pressure of the fluid 6 at the clutch can be adjusted by means of a speed of the positive displacement pump 2, in particular the clutch can be closed, in particular wherein when the positive displacement pump is operated 2 the clutch is open and/or openable in the first direction of rotation.

If such a K0 clutch is closed and the hybrid vehicle is then operated in parallel, a particularly low cooling requirement or lubrication requirement of the first consumer 3 designed as a transmission is necessary, so that the cooling/lubrication alone by means of the fluid 6 provided by the flow pump 8 is sufficient . In serial operation of such a hybrid vehicle, when the K0 clutch is open, the first consumer 3 designed as a transmission has a significantly higher cooling requirement or lubrication requirement than in parallel operation.

A valve arrangement, in particular a fifth check valve and a drain valve, is such functionally operatively coupled to the second consumer line 16.2 or functionally operatively arranged in the second consumer line 16.2 such that by means of the valve arrangement, in particular the fifth check valve, a flow of the fluid 6 in the second consumer line 16.2 from the outlet 12b of the third T-piece 12 to allows the second consumer 4 and a flow of the fluid 6 in the second consumer line 16.2 from the second consumer 4 to the outlet 12b of the third T-piece 12 is avoided. The fluid 6 can be drained from the second consumer 4 by means of the valve arrangement, in particular the drain valve.

The flow pump 8 is designed as a radial centrifugal pump.

The displacement pump 2 is designed as a gear pump.

In the intake line 9 a suction strainer 18 is arranged. Any dirt particles which could lead to an impairment of the function of the displacement pump 2 and/or the flow pump 8 are filtered out of the fluid 6 by means of the suction strainer 18 .

Reference List

1

hydraulic system

2

positive displacement pump

2a

first connection

2 B

second connection

2c

Wave

3

first consumer

4

second consumer

5

fluid reservoir

6

Fluid

7

engine

8th

flow pump

8a

drive shaft

8b

inlet port

8c

outlet port

9

intake line

10

first tee

10a

Inlet of the first tee

10b

Outlet of the first tee

10c

Branch of the first T-piece

11

second tee

11a

Second tee inlet

11 b

Outlet of the second tee

11c

Branch of the second T-piece

12

third tee

12a

Third tee inlet

12b

Outlet of the third tee

12c

Branch of the third T-piece

13

fourth tee

13a

Fourth tee inlet

13b

Fourth tee outlet

13c

Branch of the fourth tee

14

fifth tee

14a

Fifth tee inlet

14b

Fifth tee outlet

14c

Branch of the fifth tee

15.1

first connection line

15.2

second connection line

15.3

third connection line

15.4

fourth connection line

15.5

fifth connection line

15.6

sixth connection line

15.7

seventh connection line

15.8

eighth connection line

16.1

first consumer line

16.2

second consumer line

17.1

first check valve

17.2

second check valve

17.3

third check valve

17.4

fourth check valve

18

suction strainer

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• DE 102018130700 A1 [0003]
• DE 102018112663 A1 [0004]
• DE 102018112670 A1 [0005]
• DE 102011008607 A1 [0007]

Claims (10)

Hydraulic system (1) for a motor vehicle, in particular for a hybrid motor vehicle, with at least one displacement pump (2), with a first consumer (3), in particular with a transmission, with a second consumer (4), in particular with a clutch at least one fluid reservoir (5), in particular with an oil sump of the transmission, the positive displacement pump (2) having a first connection (2a) and a second connection (2b), wherein when the positive displacement pump (2) is operated in a first direction of rotation, a fluid (6) can be supplied to the positive displacement pump (2) from the fluid reservoir (5) via the second connection (2b), with the fluid (6) being discharged via the first connection (2a) when the positive displacement pump (2) is operated in the first direction of rotation of the positive displacement pump (2) and can be supplied to the first consumer (3), whereby during the operation of the positive displacement pump (2) - in a second direction of rotation opposite to the first direction of rotation - the fluid (6) of the positive displacement pump (2 ) can be supplied from the fluid reservoir (5) via the first connection (2a), wherein when the positive displacement pump (2) is operated in the second direction of rotation, the fluid (6) can be discharged from the positive displacement pump (2) via the second connection (2b) and can be supplied to the second consumer (4), and wherein the displacement pump (2) has a shaft (2c) and wherein the shaft (2c) can be driven by means of a motor (7), in particular an electric motor, characterized in that in addition a flow pump (8) is present and/or provided, the flow pump (8) having a drive shaft (8a), the drive shaft (8a) of the flow pump (8) being operatively coupled to the shaft (2c) of the displacement pump (2) and/or can be effectively coupled, the flow pump (8) having an inlet connection (8b) and an outlet connection (8c), wherein when the positive displacement pump (2) is operated in the second direction of rotation of the flow pump (8), fluid (6) then also flows out of the fluid reservoir (5) above can be fed to the inlet connection (8b), and wherein when the displacement pump (2) is operated in the second direction of rotation, the fluid (6) can be discharged from the flow pump (8) via the outlet connection (8c) and fed to the first consumer (3). Hydraulic system (1) according to the preceding claim, characterized in that when the displacement pump (2) is operated in the first direction of rotation, fluid (6) from the fluid reservoir (5) can then also be supplied to the first consumer (3) by means of the flow pump (8). is. Hydraulic system (1) according to one of the preceding claims, characterized in that an intake line (9) is fluidically connected to the fluid reservoir (5) and to an inlet (10a) of a first T-piece (10), a first connecting line (15.1 ) is fluidically connected to an outlet (10b) of the first T-piece (10) and to an inlet (11a) of a second T-piece (11), a second connecting line (15.2) being connected to an outlet (11b) of the second T -Piece (11) and with an inlet (12a) of a third T-piece (12) is fluidically connected, wherein a third connecting line (15.3) with a branch (12c) of the third T-piece (12) and with the second connection (2b) is fluidically connected to the displacement pump (2), a fourth connecting line (15.4) being fluidically connected to the first connection (2b) of the displacement pump (2) and to a branch (13c) of a fourth T-piece (14), with a fifth connecting line line (15.5) is fluidically connected to a branch (10c) of the first T-piece (10) and to an inlet (13a) of the fourth T-piece (13), a sixth connecting line (15.6) having an outlet (13b) of the fourth T-piece (13) and with an inlet (14a) of a fifth T-piece (14) is fluidically connected, wherein a first consumer line (16.1) with an outlet (14b) of the fifth T-piece (14) and with is fluidically connected to the first consumer (3), a second consumer line (16.2) being fluidically connected to an outlet (12b) of the third T-piece (12) and to the second consumer (4), a seventh connecting line (15.7) is fluidically connected to a branch (11c) of the second T-piece (11) and to the inlet port (8b) of the flow pump (8), and wherein an eighth connecting line (15.8) is connected to the outlet port (8c) of the flow pump (8) and with a branch (14c) of the fifth T-piece (14) is fluidically connected. Hydraulic system (1) according to one of the preceding claims, characterized in that a flow of the fluid (6) from the fluid reservoir (5) to the second connection (2b) of the positive displacement pump (2) is made possible by means of a first check valve (17.1) and a flow of the fluid (6) from the second connection (2b) of the positive displacement pump (2) to the fluid reservoir (5) is avoided and/or wherein a flow of the fluid (6) from the fluid reservoir (5) is prevented by means of a second check valve (17.2). the first connection (2a) of the positive displacement pump (2) and a flow of the fluid (6) from the first connection (2a) of the positive displacement pump (2) to the fluid reservoir (5) is avoided. Hydraulic system (1) according to claim 4 , characterized in that - the first check valve (17.1) is functional in this way is operatively coupled to the second connecting line (15.2) or is operatively arranged in the second connecting line (15.2) such that a flow of the fluid (6) in the second connecting line (15.2) from the outlet (11b) of the second T-piece (11) to the inlet (12a) of the third T-piece (12) and a flow of the fluid (6) in the second connection line (15.2) from the inlet (12a) of the third T-piece (12) to the outlet (11b) of the second T-piece (11) is avoided, and/or wherein - the second check valve (17.2) is functionally coupled to the fifth connecting line (15.5) or is functionally arranged in the fifth connecting line (15.5). that allows a flow of the fluid (6) in the fifth connecting line (15.5) from the branch (10c) of the first T-piece (10) to the inlet (13a) of the fourth T-piece (13) and a flow of the fluid (6) in the fifth connecting line (15.5) vo n the inlet (13a) of the fourth T-piece (13) to the branch (10c) of the first T-piece (10) is avoided, and/or wherein - a third check valve (17.3) is functionally effective in this way with the sixth connecting line ( 15.6) is coupled or is arranged in the sixth connecting line (15.6) in such a functionally effective manner that a flow of the fluid (6) in the sixth connecting line (15.6) from the outlet (13b) of the fourth T-piece (13) to the inlet (14a) of the fifth T-piece (14) and a flow of the fluid (6) in the sixth connecting line (15.6) from the inlet (14a) of the fifth T-piece (14) to the outlet (13b) of the fourth T piece (13) is avoided, and/or wherein - a fourth non-return valve (17.4) is functionally coupled to the seventh connecting line (15.7) or is arranged in the seventh connecting line (15.7) in such a functionally effective manner that a flow of the fluid (6) in the seventh connecting line (15 .7) from the branch (11c) of the second T-piece (11) to the inlet connection (8b) of the flow pump (8) and a flow of the fluid (6) in the seventh connecting line (15.7) from the inlet connection (8b) the flow pump (8) to the branch (11c) of the second T-piece (11) is avoided. Hydraulic system (1) according to one of the preceding claims, characterized in that the first consumer (3) is designed as a transmission for a motor vehicle or is provided in a transmission for a motor vehicle, so that by means of the fluid (6) at least one component in particular a gear wheel, a bearing and/or a sliding sleeve of the transmission which can be lubricated and/or cooled. Hydraulic system (1) according to one of the preceding claims, characterized in that the second consumer (4) is designed as a clutch of the motor vehicle, in particular as a K0 clutch of the hybrid vehicle, the clutch being actuatable by means of the fluid (6), wherein when the positive displacement pump (2) is operated in the second direction of rotation, a pressure of the fluid (6) at the clutch can be adjusted by means of a rotational speed of the positive displacement pump (2), in particular the clutch can be closed, in particular wherein when the positive displacement pump (2) is operated the clutch can be opened and/or opened in the first direction of rotation. Hydraulic system (1) according to one of claims 3 until 7 , characterized in that a valve arrangement, in particular a fifth check valve and a drain valve, is functionally operatively coupled to the second consumer line (16.2) or is arranged in such a functionally operative manner in the second consumer line (16.2) that by means of the valve arrangement, in particular the fifth check valve, a flow of the fluid (6) in the second consumer line (16.2) from the outlet (12b) of the third T-piece (12) to the second consumer (4) and a flow of the fluid (6) in the second consumer line (16.2) from the second consumer (4) to the outlet (12b) of the third T-piece (12), the fluid (2) being able to be drained from the second consumer (4) by means of the valve arrangement, in particular the drain valve . Hydraulic system (1) according to one of the preceding claims, characterized in that the flow pump (8) is designed as a radial centrifugal pump. Hydraulic system (1) according to one of the preceding claims, characterized in that the displacement pump (2) is designed as a gear pump.

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