DE102020207140A1 - Hydraulic system for a transmission of a motor vehicle drive train - Google Patents

Abstract

A hydraulic system (HY) is proposed. The hydraulic system (HY) has a first pump (EP) for supplying pressure to a first pressure circuit (H1) and a second pump (MP) for supplying pressure to a second pressure circuit (H2). The first pressure circuit (H1) is provided for supplying pressure to at least one shift actuator (SK1, SK2) of the transmission (G). The second pressure circuit (H2) is provided for cooling and / or lubricating at least one component of the transmission (G). An output of the second pump (MP) is connected to the first pressure circuit (H1) via a check valve (SV). A connecting line (L) between the outlet of the second pump (MP) and the second pressure circuit (H2) can be shut off and released as required by a spring-loaded switching valve (PV). A switching position of the switching valve (PV) is dependent on a pilot pressure which can be set in the range of an electro-hydraulic pilot stage (APV). Furthermore, a transmission (G) with such a hydraulic system (HY) and a drive train for a motor vehicle with such a transmission (G) are proposed.

Description

The invention relates to a hydraulic system for a transmission of a motor vehicle drive train. The invention also relates to a transmission with such a hydraulic system, as well as a motor vehicle drive train with such a transmission.

The patent application DE 10 2004 025 764 A1 describes a hydraulic circuit for supplying oil to an automatic transmission for motor vehicles. The hydraulic circuit has a low-pressure circuit and a high-pressure circuit, each of which is supplied with volume flow by a pump. The pressure in the low pressure circuit can be adjusted using a pressure relief valve. By activating the pressure relief valve, a pressure level of the low pressure circuit can be raised to a pressure level of the high pressure circuit, whereby a check valve opens between the two pressure circuits. As a result, the volume flows of both pumps for supplying the high-pressure circuit can be summed up if necessary in order to ensure the pressure supply of the shift actuators during the shifting processes. Outside of switching processes, the pump assigned to the high-pressure circuit only needs to replenish the leakage of the switching actuators, so that only a small volume flow with high pressure is required.

In transmissions with a high number of gears, the proportion of time in which both pumps work together to supply the high-pressure circuit increases, so that the energy consumption of the pumps increases. In general and regardless of the number of gears in the transmission, it is desirable to keep the energy consumption of the pumps as low as possible.

From the unpublished application DE 10 2019 202 138.7 A hydraulic system for a transmission of a motor vehicle is known to the applicant. The hydraulic system has a first pump for supplying pressure to a first pressure circuit and a second pump for supplying pressure to a second pressure circuit. The first pressure circuit is provided for supplying pressure to at least one shift actuator of the transmission. The second pressure circuit is provided for cooling and / or lubricating at least one component of the transmission. An output of the second pump is connected to the first pressure circuit via a check valve. A connecting line between the outlet of the second pump and the second pressure circuit can be shut off if necessary by a spring-loaded switching valve. A switching position of the switching valve is dependent on the pressure in the first pressure circuit.

It is the object of the invention to provide an improved hydraulic system.

The object is achieved by the features of claim 1. Advantageous embodiments result from the subclaims, the description and the figures.

To achieve the object, a hydraulic system for a transmission of a motor vehicle drive train is proposed which has a first pump for supplying pressure to a first pressure circuit and a second pump for supplying pressure to a second pressure circuit. The two pumps can be designed as separate pumps or as a dual-circuit pump. The first pressure circuit is provided for supplying pressure to at least one shift actuator of the transmission. The second pressure circuit is provided for cooling and / or lubricating at least one component of the transmission. An output of the second pump is connected to the first pressure circuit via a check valve, so that the first pressure circuit can be supplied with hydraulic fluid via the check valve by the second pump. The hydraulic system has a spring-loaded switching valve. The switching valve is set up to open and shut off a connecting line between the output of the second pump and the second pressure circuit as required.

According to the invention, the switching position of the switching valve is dependent on a pilot pressure which can be set in the area of an electrohydraulic pilot stage.

The pilot control of the switching valve via the pilot control stage makes it possible to supply the first pressure circuit with hydraulic fluid via both pumps, independently of the pressure in the first pressure circuit. This is advantageous when the first pressure circuit has a high hydraulic fluid volume requirement in order to be able to represent a required operating state of the transmission.

Furthermore, the output of the second pump can be connected to the second pressure circuit via the switching valve, regardless of the pressure of the first pressure circuit. If the pressure in the second pressure circuit is lower than the pressure in the first pressure circuit, the hydraulic system can be operated with a lower power consumption, since the second pump then only works against the lower pressure of the second hydraulic circuit.

The connecting line between the output of the second pump and the pressure circuit can be switched by means of the switching valve in such a way that the connecting line is blocked at a pilot pressure or at an output pressure of the pilot stage less than a limit value, and that the connecting line is blocked at a Pilot pressure greater than the limit value or equal to the limit value is released.

The limit value can be selected such that the connecting line is blocked by the switching valve when the hydraulic fluid volume requirement of the first pressure circuit is high. A sufficient supply of various shift elements of the transmission is then guaranteed via the first pressure circuit.

Furthermore, by suitably defining the limit value of the pilot control pressure, it can be ensured that the second pump only works against the hydraulic resistance of the second pressure circuit when the hydraulic fluid volume requirement of the first pressure circuit is low. Such an operating point can occur, for example, in hydraulically or mechanically lockable or detentable actuators in the first pressure circuit, which do not require high pressure to maintain the operating state.

The first pressure circuit can be provided downstream of a delivery side of the first pump and upstream of a pilot-controllable pressure regulating valve, such as a pressure limiting valve. The pressure in the first pressure circuit can then be set with little control and regulation effort as a function of the current operating state of the transmission.

If the second pressure circuit is downstream of the pilot-controllable pressure regulating valve, a supply of the first pressure circuit with hydraulic fluid with little effort is prioritized over the supply of the second pressure circuit.

A delivery side of the second pump can be connected to the second pressure circuit via the switching valve directly downstream of the pilot-controllable pressure regulating valve. It is then ensured in a structurally simple manner that the entire second pressure circuit is acted upon by the delivery flow of the second pump downstream of the pilot-controllable pressure regulating valve.

In a further development of the hydraulic system according to the invention, the pilot pressure of the pilot stage acts directly on a pilot connection of a parking lock valve. When a pilot pressure is present that is greater than or equal to a second limit value of the pilot pressure, the parking lock valve changes to a switching position in which the parking lock valve releases another connecting line. If an actuating pressure can be applied to a parking lock cylinder via the connecting line from the first pressure circuit, by means of which a parking lock of the transmission can be transferred to its designed operating state or can be kept in its designed operating state, undesired engagement of the parking locks can be avoided with little control and regulation effort.

If the first limit value is greater than the second limit value of the pilot control pressure, it is ensured that the parking lock is hydraulically actuated in the direction of its designed state when there is a high hydraulic fluid volume requirement of the first pressure circuit.

An embodiment of the hydraulic system according to the invention which is economical in terms of installation space and is characterized by a high power density comprises two 9/2-way valves which are arranged in the first pressure circuit and to which a 4/2-way valve is connected upstream. The 4/2-way valve, which can be designed as a pressure regulating valve, is set up to set a pressure. This pressure can be passed on via the 9/2-way valves to actuate several piston-cylinder units in the direction of the piston chambers of the piston-cylinder units. Pistons of the piston-cylinder units can be connected to so-called shift rods in order to be able to operate shift elements, such as synchronizers of form-fitting shift elements.

In an embodiment of the hydraulic system according to the invention that is easy to operate, the 9/2-way valves have two discrete limit switch positions. The 9/2-way valves can each be spring-loaded in the direction of one of the discrete limit switch positions and can be directly hydraulically actuated in the direction of the other discrete limit switch position via a pilot control stage.

In the present case, discrete end positions of a directional valve are understood to mean switching positions that a directional valve has in a defined operating state range. This means that such a directional control valve does not assume any intermediate switching positions during operation that lie between the discrete limit switching positions. Such a directional valve only passes over the intermediate points during a switchover process between the two discrete limit switch positions.

The 4/2-way valve can also have two limit switch positions and be spring-loaded in the direction of one of the limit switch positions and directly hydraulically actuated in the direction of the other limit switch position via a pilot stage and can be transferred to any number of intermediate switch positions. The pressure in the area of the 4/2-way valve can then be continuously varied in a structurally simple manner.

An electrically drivable further pump can be provided, the output side of which is connected to the first pressure circuit. Then the first pressure circuit is also in the operating states of the The hydraulic system according to the invention can be sufficiently supplied with hydraulic fluid in which the first pump and the second pump do not provide a hydraulic fluid volume flow or an insufficient hydraulic fluid volume flow.

The check valve is preferably spring-loaded. In this way, unintentional opening of the check valve, for example due to mechanical vibrations, can be avoided.

The hydraulic system can be part of the transmission, so that the elements of the hydraulic system are structurally integrated into the transmission. The transmission with the hydraulic system can be part of a motor vehicle drive train.

The invention is not restricted to the specified combination of the features of the independent claims or the claims dependent thereon. In addition, there are possibilities of combining individual features with one another, also insofar as they emerge from the claims, the following description of embodiments or directly from the drawing. The reference of the claims to the drawings through the use of reference signs is not intended to limit the scope of protection of the claims.

Preferred developments emerge from the subclaims and the following description. An exemplary embodiment of the invention is explained in more detail with reference to the drawing, without being restricted thereto.

• 1 eine schematische Darstellung eines Kraftfahrzeug-Antriebsstrangs mit einem Doppelkupplungsgetriebe; und
• 2 ein Hydraulikschema gemäß einem Ausführungsbeispiel des erfindungsgemäßen Hydrauliksystems.

Show it:

• 1 a schematic representation of a motor vehicle drive train with a dual clutch transmission; and
• 2 a hydraulic scheme according to an embodiment of the hydraulic system according to the invention.

1 shows a schematic representation of a motor vehicle drive train 1 with a transmission G , which is a hydraulic system HY having. The gear G is designed as a dual clutch transmission, for example. The gear G has an input shaft ON on which via a disconnect clutch K0 with a drive shaft GW1 is connectable. An internal combustion engine VM is with the input shaft ON connected. A rotor of an electrical machine EM2 is with the drive shaft GW1 connected.

By closing a first clutch K1 is the drive shaft GW1 with a first partial transmission TG1 connectable. By engaging a second clutch K2 is the drive shaft GW1 with a second partial transmission TG2 connectable. Each of the sub-transmissions TG1 , TG2 are different translation levels i1 , i2 , i3 , i4 assigned, which by controlling a hydraulic switching actuator SK1 , SK2 selectively with an output shaft GW2 are connectable.

The output shaft GW2 is with a differential gear AG connected, which is the one on the output shaft GW2 applied power to drive wheels DW of the motor vehicle drive train distributed. The first clutch K1 and the second clutch K2 form the double clutch of the transmission G , and are each through hydraulic actuators AK1 , AK2 actuated. The disconnect clutch K0 is by a hydraulic actuator AK0 operable.

The gear G also has a central synchronization ZSY on. This includes two switchable paths for torque transmission, which are the input shafts of the two sub-transmissions TG1 , TG2 connect with each other. Each of the paths have a sync translation iZ1 , iZ2 and a clutch Z1 , Z2 assigned. The two clutches Z1 , Z2 are by means of hydraulic actuators AZ1 , AZ2 operable.

The gear G has a parking lock PS on. The parking lock PS includes a parking lock gear PSR , which with the output shaft GW2 connected is. The parking lock wheel PSR has a toothing into which a pawl can engage. The pawl engages in the teeth of the parking lock gear PSR one, so is the rotary motion of the output shaft GW2 inhibited. The pawl is operated by a hydraulic actuator APS controlled.

The switching actuators SK1 , SK2 as well as the actuators AK1 , AK2 , AK0 , AZ1 , AZ2 , APS are through the hydraulic system HY actuated. The pressure supply of the hydraulic system HY takes place via a first pump MP1 and a second pump MP2 . A third pump can also be used EP be provided by one exclusive to the first pump EP assigned electric motor EM1 is driven. The pumps MP1 and MP2 are from the drive shaft GW1 driven by the electric machine EM2 , or with the clutch closed K0 by the internal combustion engine VM is driven. All pumps MP1 , MP2 and EP suck hydraulic fluid from a tank T of the hydraulic system HY and deliver the hydraulic fluid to a hydraulic control unit HCU which the oil supply to the consumers of the hydraulic system HY controls. The gear G has an electronic control unit ECU on which at least to control the hydraulic system HY is set up. A temperature sensor TS measures the temperature of the hydraulic fluid in the tank T , and transmits the information to the electronic control unit ECU .

The hydraulic control unit HCU is in 1 shown as a single assembly. This is only to be regarded as an example. The hydraulic control unit HCU can be structurally divided into several individual control units, which are connected to one another via suitable hydraulic interfaces.

The structure of the in 1 illustrated transmission G is only to be regarded as an example. The gear G could do without the electric machine EM2 and without the disconnect clutch K0 be executed so that the internal combustion engine VM with the drive shaft GW1 is constantly connected. The partial transmission TG1 , TG2 could have more than just four translation levels i1 , i2 , i3 , i4 exhibit. Further switching actuator units could be provided.

The two sub-transmissions could be used to form one or more winding turns TG1 , TG2 be connected via one or more additional clutches. The gear G could without the central synchronization ZSY be trained. The gear G could also have only a single shift actuator unit, which is used, for example, to switch between a first gear and a second gear of the transmission G is set up.

2 shows part of the circuit diagram of the hydraulic system HY according to a possible embodiment. The hydraulic system HY instructs the first pump MP1 and the second pump MP2 on. The first pump MP1 serves to supply pressure to a first pressure circuit H1 of the hydraulic system HY . The first pressure circle H1 is the switching actuators SK1 , SK2 of the transmission G assigned. The second pump MP2 serves to supply pressure to a second pressure circuit H2 of the hydraulic system HY , via which, for example, the lubrication and / or cooling of the gearbox G is supplied with hydraulic fluid. Both pumps MP1 , MP2 suck hydraulic fluid through a filter FI from the tank T on.

An output of the second pump MP2 is via a check valve SV with the first pressure circle H1 so connected that the second pump MP2 Hydraulic fluid in the first pressure circuit H1 can promote. The check valve takes in the opposite direction SV the blocking position, so that a delivery of hydraulic fluid from the first pump MP1 in the second pressure circle H2 is prevented. The check valve SV is preloaded by a spring in the locked position.

The output of the second pump MP2 is via a connecting line L. with the second pressure circle H2 connected. In the connecting line L. is a spring-loaded and hydraulically pilot operated switching valve PV arranged. A pilot connection of the switching valve PV is with the output of an actuator APV or directly connected to an electro-hydraulic pilot stage.

The switching valve PV has two discrete switch positions. Is the output pressure of the electro-hydraulic pilot control stage APV less than a limit value, the switching valve remains PV due to the spring preload in its first discrete limit switch position. In the first discrete limit switch position, which is shown in 2 is shown, locks the switching valve PV the connection between the output of the second pump MP2 and the second pressure circuit H2 . Will be the second pump MP2 in this operating state of the switching valve PV operated, the second pump delivers MP2 via the check valve SV in the first pressure circle H1 .

This operating state is, for example, when filling the switching actuators SK1 , SK2 taken. Because this operating state is characterized by a high volume flow requirement and a medium pressure requirement, and is only of a relatively short duration. In this operating state, both pumps deliver MP1 , MP2 in the first pressure circle H1 so that the high volume flow requirement can be met in a short time.

Is the output pressure of the electro-hydraulic pilot control stage APV greater than or equal to the limit value, the switching valve switches PV to its second discrete limit switch position. The switching valve is in the second discrete limit switch position PV the connection between the output of the second pump MP2 and the second pressure circuit H2 free. Then the second pump works MP2 only against the hydraulic resistance of the second pressure circuit H2 .

This operating state is, for example, for the leakage compensation of the first pressure circuit H1 assigned actuators are important if they are not mechanically or hydraulically detented or locked. This is because a relatively high pressure and a low volume flow requirement are required for this.

The pressure in the first pressure circuit H1 is via a pressure control valve PSYS regulated. The pressure control valve PSYS , which is also referred to below as the system pressure valve, is downstream of the delivery side of the first pump MP1 arranged. At a pilot connection of the system pressure valve PSYS a pilot pressure acts directly, which is generated by an additional actuator ASYS or a further pre-control stage is continuously adjustable. The pilot pressure has the same effect as a spring force on the system pressure valve PSYS can be applied and acts in the direction of a first limit switch position of the system pressure valve PSYS . In the first limit switch position of the System pressure valve PSYS is the system pressure valve PSYS closed.

Downstream of the system pressure valve PSYS the second pressure circuit closes H2 on. The second pressure circle H2 is via the system pressure valve PSYS only then from the first pump MP1 supplied with hydraulic fluid when the first pressure circuit H1 according to the specification via the further pre-tax stage ASYS is saturated. The one through the pump valve PV switchable connection line L. opens downstream of the pump valve PV and directly downstream of the system pressure valve PSYS in the second pressure circle H2 .

In addition, is downstream of the system pressure valve PSYS a so-called radiator protection valve KSV intended. Via the radiator protection valve KSV is hydraulic fluid from a pressure threshold of the pressure in the second pressure circuit H2 in the direction of a connection of a cooling oil distributor valve KÜV and also in the direction of the suction side of the pumps EP and MP guidable. To the hydraulic fluid volume flow in the direction of the suction side of the pumps MP1 and MP2 is performed, to be able to limit, is present between the radiator protection valve KSV and the suction side a throttle D1 intended.

Upstream of the radiator protection valve KSV branches off a line L2 towards a cooler KU on the output side with another connection of the cooling oil distributor valve KUV communicates. The cooling oil distributor valve KUV is designed as a pilot-controlled, regulated 3/2-way valve and for the regulated supply of cooling oil to the separating clutch K0 as well as the couplings K1 and K2 intended. The disconnect clutch K0 as well as the couplings K1 and K2 are for this purpose downstream of the cooling oil distribution valve KUV in the second pressure circle H2 arranged. The pilot pressure of the pilot stage acts for pilot control APV directly to a pilot connection of the cooling oil distributor valve KUV , that against the pilot pressure of the pilot stage APV is sprung.

In addition, the cooler is standing KU On the output side with a pilot controllable cooling valve KUVEM in connection, which is designed as a 2/2-way valve and via which the electrical machine EM2 can be charged with cooling oil.

The pilot pressure of the pilot stage APV also acts directly on a pilot control connection of a parking lock valve PSV, which is directed towards an in 2 discrete limit switch position shown is spring-loaded. The parking lock valve PSV goes when there is pilot pressure of the pilot stage APV greater than or equal to a second limit value of the pilot pressure into a second discrete limit switch position. In the second discrete limit switch position, the parking lock valve PSV provides another connection line L3 free. Via the further connection line L3 becomes the actuator APS the parking lock PS , which is designed as a so-called parking lock cylinder, starting from the first pressure circuit H1 applied with an actuation pressure. The parking lock is activated by means of the actuation pressure PS of the transmission G transferable to their designed operating state or durable in the designed operating state.

The first limit value of the pilot pressure of the pilot stage APV is greater than the second limit value of the pilot pressure. This means that the response limit of the parking lock valve PSV is lower than the response limit of the pump valve PV . This ensures that the parking lock PS is then designed when the second pump MP2 via the pump valve PV with the second pressure circle H2 connected is.

The switching actuators SK1 , SK2 and the actuators AZ1 , AZ2 are in the present case designed as piston-cylinder units. Pistons KSK1 , KSK2 , KAZ1 , KAZ2 the switching actuators SK1 , SK2 and the actuators AZ1 , AZ2 are above shift rods SSK1, SSK2, SAZ1, SAZ2 with shift elements of the transmission G in connection. There are six gear ratios for forward travel and one gear ratio for reverse travel in the transmission via the shifting elements G representable.

Piston chambers SK1A , SK1B , SK2A , SK2B , AZ1A , AZ1B , AZ2A and AZ2B the piston-cylinder units SK1 , SK2 , AZ1 and AZ2 are via two switching valves MUX1 , MUX2 and another pilot valve MUX3 starting from an actuator ASKAZ can be pressurized. The actuator ASKAZ is designed as an electro-hydraulic pilot stage, on which the pressure of the first pressure circuit H1 is applied. About the on the piston-cylinder units SK1 , SK2 , AZ1 and AZ2 applied pressure can the transmission G be kept in the currently requested operating state or transferred to such an operating state.

The switching valves MUX1 and MUX2 are designed as 9/2-way valves, each with actuators AMUX1 and AMUX2 can be switched between two discrete limit switch positions. Here are the switching valves MUX1 and MUX2 spring-loaded in the direction of one of the limit switch positions and in the direction of the other limit switch position via the actuators AMUX1 and AMUX2 can be operated directly hydraulically. The actuators AMUX1 and AMUX2 are designed as hydraulic switches or solenoid valves to which the pressure of the first pressure circuit is applied H1 is applied.

The control valve MUX3 is between the actuator ASKAZ and the switching valves MUX1 , MUX2 arranged. In addition, the control valve is MUX3 designed as a 4/2-way valve, in the area of which the pressure is in addition to the actuator ASKAZ is adjustable. The one via the control valve MUX3 continuously variable pressure is via the switching valves MUX1 and MUX2 in the direction of the piston chambers SK1A , SK1B , SK2A , SK2B , AZ1A , AZ1B , AZ2A and AZ2B forwardable to the piston-cylinder units SK1 , SK2 , AZ1 and AZ2 to operate.

For pilot control of the control valve MUX3 a pilot pressure of an actuator acts AMUX3 directly to a pilot control connection of the control valve MUX3 , which is spring-loaded counteracting the pilot pressure in the direction of a first limit switch position. The first limit switch position of the control valve MUX3 is in 2 shown. In the first limit switch position of the control valve MUX3 is the pressure going in the direction of the switching valves MUX1 and MUX2 is passed on, minimally or essentially equal to zero. In addition, is the control valve MUX3 from the pilot pressure of the actuator AMUX3 can be converted into a second limit switch position against the applied spring force. The pressure in the second limit switch position of the control valve MUX3 on the switching valves MUX1 and MUX2 is applied is maximum and corresponds to the pressure in the area of the actuator ASKAZ is set. To the switching actuators SK1 and SK2 as well as the actuators AZ1 and AZ2 The pressure control valve can be operated to the required extent MUX3 can be converted into any number of intermediate switch positions between the two limit switch positions.

Furthermore, there is the pressure of the first pressure circuit H1 on the actuators AK0 , AK1 and AK2 at the in 2 shown embodiment of the hydraulic system HY are designed as electrohydraulic control valves. In the field of actuators AK0 , AK1 and AK2 is an actuation pressure for each of the clutches K1 and K2 as well as for the disconnect clutch K0 adjustable.

The piston chamber SK1A is in the two discrete limit switch positions of the switching valves MUX1 and MUX2 that do this without corresponding control by the actuators AMUX1 and AMUX2 have with the one about the actuator ASKAZ set pressure applied. The control valve must also be used for this MUX3 have the required limit switch position or intermediate switch position.

The one on the piston chamber SK1A The pressure that is present also acts directly on a pilot control connection of the cooling valve KUVEM . When the pressure is appropriate, the cooling valve is activated KUVEM from the in 2 shown first limit switch position in which the electrical machine EM2 via the cooling valve KUVEM can be supplied with cooling oil, transferred against the spring preload into its second limit switch position. The cooling valve blocks in the second limit switch position KUVEM the cooling oil supply for the electrical machine EM2 what in different operating states of the motor vehicle drive train according to 1 contributes to the reduction of hydraulic power losses.

In addition, the third pump EP be provided to the hydraulic system HY even with stationary pumps MP1 and MP2 to be supplied with hydraulic fluid. An output side of the third pump EP stands with the first pressure circle H1 in connection. Depending on the particular application, it can be provided that the third pump EP in the area of an interface S1 or in the area of an interface S2 with the first pressure circle H1 communicates.

The first interface S1 is upstream of the actuator ASYS intended. When connecting the third pump EP in the area of the first interface S1 and a corresponding design of the delivery rate of the third pump EP the full range of functions of the hydraulic system can be accessed via the third pump HY to provide.

The second interface S2 lies between the switching valve MUX1 and the piston chamber SK1A the piston-cylinder unit SK1 . The functional scope of the hydraulic system HY is restricted when the third pump EP in the area of the second interface S2 is connected and only from the third pump EP Hydraulic fluid in the line system of the hydraulic system HY is initiated.

The two pumps MP1 and MP2 can be separate pumps. Furthermore, there is also the possibility that each pump is a pump flow of a double-flow pump, such as a double-stroke vane pump or the like.

List of reference symbols

AG

Differential gear

AK0

Actuator of the disconnect clutch

AK1

Actuator of the first clutch

AK2

Second clutch actuator

AMUX1

Actuator of the switching valve MUX1

AMUX2

Actuator of the switching valve MUX2

AMUX3

Actuator of the control valve MUX3

ON

Input shaft

APS

Actuator

APV

Pump valve actuator

ASKAZ

Actuator of the switching actuator system

ASYS

Actuator of the system pressure valve

AZ1

Actuator

AZ1A

Piston chamber

AZ1B

Piston chamber

AZ2

Actuator

AZ2A

Piston chamber

AZ2B

Piston chamber

DW

drive wheel

D1

throttle

ECU

electronic control unit

EM1

Electric motor

EM2

electric machine

EP

third pump

FI

filter

G

transmission

GW1

drive shaft

GW2

Output shaft

HCU

hydraulic control unit

HY

Hydraulic system

H1

first pressure circle

H2

second pressure circle

iZ1, iZ2

Sync translation

i1, i2, i3, i4

Translation levels

KAZ1

Pistons

KAZ2

Pistons

KSK1

Pistons

KSK2

Pistons

KSV

Radiator protection valve

KU

cooler

KUV

Cooling oil distribution valve

KUVEM

Cooling valve

K0

Disconnect clutch

K1

first clutch

K2

second clutch

L.

Connecting line

L2

management

L3

further connection line

MP1

first pump

MP2

second pump

MUX1

Switching valve

MUX2

Switching valve

MUX3

Control valve

PS

Parking lock

PSR

Parking lock wheel

PSYS

Pressure control valve

PV

Switching valve

SK1

Switching actuator

SK1A

Piston chamber

SK1B

Piston chamber

SK2

Switching actuator

SK2A

Piston chamber

SK2B

Piston chamber

SV

check valve

S1, S2

interface

T

tank

TG1

first partial transmission

TG2

second partial transmission

TS

Temperature sensor

VM

Internal combustion engine

ZSY

Central synchronization

Z1, Z2

coupling

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed 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 102004025764 A1 [0002]
• DE 102019202138 [0004]

Claims (15)

Hydraulic system (HY) for a transmission (G) of a motor vehicle drive train, the hydraulic system (HY) having a first pump (MP1) for supplying pressure to a first pressure circuit (H1) and a second pump (MP2) for supplying pressure to a second pressure circuit (H2) - wherein the first pressure circuit (H1) is provided for supplying pressure to at least one switching actuator (SK1, SK2) which is used to actuate a switching element of the transmission (G), - the second pressure circuit (H2) for cooling and / or lubrication of at least one component of the transmission (G) is provided, - an output of the second pump (MP2) being connected to the first pressure circuit (H1) via a check valve (SV), so that the first pressure circuit (H1) via the check valve (SV) can be supplied with hydraulic fluid by the second pump (MP2), and wherein a connecting line (L) between the output of the second pump (MP2) and the second pressure circuit (H2) is provided by a spring-loaded switching valve (PV) Can be shut off and released if necessary, characterized in that a switching position of the switching valve (PV) is dependent on a pilot pressure which can be set in the area of an electrohydraulic pilot stage (APV). Hydraulic system (HY) Claim 1 , characterized in that the switching valve (PV) blocks the connecting line (L) - when the pilot pressure is less than a limit value, and - releases it when the pilot pressure is greater than or equal to the limit value. Hydraulic system according to Claim 1 or 2 , characterized in that the first pressure circuit (H1) is provided downstream of a delivery side of the first pump (MP1) and upstream of a pilot-controllable pressure control valve (PSYS). Hydraulic system according to Claim 3 , characterized in that the second pressure circuit (H2) is downstream of the pilot-controllable pressure regulating valve (PSYS). Hydraulic system according to Claim 3 or 4th , characterized in that a delivery side of the second pump (MP2) can be connected to the second pressure circuit (H2) via the switching valve (PV) directly downstream of the pilot-controllable pressure regulating valve (PSYS). Hydraulic system according to one of the preceding claims, characterized in that the pilot pressure of the pilot stage (APV) acts directly on a pilot connection of a parking lock valve (PSV) which, when a pilot pressure is greater than or equal to a second limit value of the pilot pressure, changes into a switching position in which the Parking lock valve (PSV) releases a further connecting line (L3) and a parking lock cylinder (APS) can be acted upon via the further connecting line (L3) with an actuating pressure from the first pressure circuit (H1), by means of which a parking lock (PS) of the transmission (G) is in its designed operating state can be transferred or can be maintained in the designed operating state. Hydraulic system according to Claim 6 , characterized in that the first limit value is greater than the second limit value of the pilot pressure. Hydraulic system according to one of the preceding claims, characterized in that two 9/2-way valves (MUX1, MUX2) and a 4/2-way valve (MUX3) connected upstream of these are provided, with one in the area of the 4/2-way valve (MUX3) Pressure can be set, which via the 9/2-way valves (MUX1, MUX2) is used to actuate several piston-cylinder units (SK1, SK2, AZ1, AZ2) in the direction of piston chambers (SK1A, SK1B, SK2A, SK2B, AZ1A, AZ1B, AZ2A, AZ2B) of the piston-cylinder units (SK1, SK2, AZ1, AZ2) can be passed on. Hydraulic system according to Claim 8 , characterized in that the 9/2-way valves (MUX1, MUX2) have two discrete limit switch positions, the 9/2-way valves (MUX1, MUX2) being spring-loaded in the direction of one of the discrete limit switch positions and in the direction of the other discrete limit switch position via an actuator (AMUX1, AMUX2) can be operated directly hydraulically. Hydraulic system according to Claim 8 or 9 , characterized in that the 4/2-way valve (MUX3) has two limit switch positions, the 4/2-way valve (MUX3) being spring-loaded in the direction of one of the limit switch positions and directly hydraulically actuated in the direction of the other limit switch position via an actuator (AMUX3) and can be converted into any number of intermediate switching positions. Hydraulic system according to one of the preceding claims, characterized in that a further electrically drivable pump (EP) is provided, the output side of which is connected to the first pressure circuit (H1). Hydraulic system according to one of the preceding claims, characterized in that the pilot pressure of the pilot stage (APV) acts directly on a pilot connection of a cooling oil distribution valve (KUV) of the second pressure circuit (H2), the cooling oil distribution valve (KUV) clutches depending on the pilot pressure of Transmission (G) or an electrical machine (EM2) of a drive train running with the transmission (G) for cooling with hydraulic fluid. Hydraulic system according to Claim 12 , characterized in that a pilot-controllable cooling valve (KUVEM) is provided between the cooling oil distributor valve (KUV) and the electrical machine (EM2), which includes a pilot connection on which a pressure acts directly between one of the 9/2 -Way valves (MUX1) and a piston chamber (SK1A) one of the piston-cylinder units (SK1) is applied, the cooling valve (KUVEM) blocking the connection between the cooling oil distribution valve (KUV) and the electrical machine (EM2), when the pressure at the pilot connection is greater than a threshold value. Transmission (G) for a motor vehicle, characterized by a hydraulic system (HY) according to one of the preceding claims. Drive train for a motor vehicle, characterized by a transmission (G) according to Claim 14 .

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