DE102016206562B4 - Hydraulic system and method for operating a parking brake device by means of a hydraulic system - Google Patents

Abstract

Hydraulic system (1) of an automatic transmission (2) with a parking brake device (21) with a parking brake valve (PSV) which can be applied against a control force, in which a main pressure (p_sys) can be applied in a defined operating state range of a position valve (POSV), which counteracts a control force via a pilot control is carried out vorsteuerbar, wherein a pressure chamber (22) of a parking lock cylinder (23) in a defined operating state range of the parking brake valve (PSV) for laying out the parking brake device (21) or hydraulically holding the parking brake device (21) in the designed state via the parking brake valve ( PSV) with the main pressure (p_sys) can be acted upon, while the pressure chamber (22) in another operating state range of the parking brake valve (PSV) via this with a non-pressurized area (24) is in communication and the parking brake device (21) can be converted into its inserted operating state , characterized in that the parking brake valve (PSV) can be held above its defined operating state range against a defined pressure threshold of the main pressure (p_sys) and / or an applicable pilot pressure (p_EDS4) and the position valve (POSV) starts at a pressure threshold of the applicable pilot pressure (p_EDS3) Pilot control against the actuating force in another operating state range can be converted, in which the supply line of the main pressure (p_sys) to the parking brake valve (PSV) in the region of the position valve (POSV) is locked and the parking brake valve (PSV) via the position valve (POSV) with a Vorbefüllventil ( 31) is in operative connection, which is arranged between the positional valve (POSV) and a non-pressurized region (32) and whose response limit corresponds to a pressure level in the pressure chamber (22) of the parking lock cylinder (23), to which the parking brake device (21) in its inserted state is convertible.

Description

The invention relates to a hydraulic system and a method for operating a parking brake device by means of a hydraulic system according to the closer defined in the preamble of claim 1 and 10, respectively.

From the DE 10 2013 222 984 A1 a transmission device is known with a hydraulic system comprising a pump device. The transmission device is designed as a double-clutch transmission. A first pump unit of the pump device is designed as an adjustable vane pump, while a second pump unit of the pump device is a fixed displacement pump.

In the present case, the first pump unit represents the main transmission pump, which is coupled in a manner known per se with a transmission input shaft not illustrated in detail in the drawing and can therefore be driven by a drive machine which can be connected to the transmission input shaft of the transmission device. In contrast, the second pump unit is coupled to the transmission output shaft, which in turn is connectable in known manner to an output of a vehicle drive train designed with the transmission device and driven at vehicle speeds greater than zero with a drive speed corresponding to an output speed. A pressure side of the first pump unit communicates with a primary pressure circuit of the hydraulic system, in which a system pressure or a main pressure is present, which in turn is adjustable via a pre-controllable system pressure valve.

About the first pump unit is a demand-based hydraulic supply assigned actuators. Thus, for example, the two clutches of a dual-clutch system of the transmission device associated with clutch valves and a parking brake system supplied from the primary pressure circuit and the first pump unit with hydraulic fluid. The second pump unit is associated with another pressure circuit, which is a separate low-pressure circuit, and supplies a lubrication spider of a wheelset cooling and further an all-wheel clutch, which is a so-called hang-on clutch.

The parking brake system or the parking brake device of the transmission device is formed with a counter-actuating force of a spring device vorsteubaren parking lock valve on which in a defined operating state range of a position valve, the main pressure can be applied. The positional valve is designed to be pilot-controlled against a force of a spring device via a pilot control. A pressure chamber of a parking lock cylinder can be acted upon in a defined operating state range of the parking lock valve for laying out the parking lock device or hydraulically holding the parking lock device in the designed state via the parking lock valve with the main pressure of the primary pressure circuit, while the pressure chamber in another operating state range of the parking lock valve with this with a non-pressurized area in Connection is and the parking brake device is in its inserted operating state can be transferred.

Disadvantageously, so-called single errors in the area of the parking lock valve and / or the position valve cause undesired actuations of the parking lock system during unfavorable operating state profiles of the hydraulic system or prevent requested operating state changes of the parking lock device, which is undesirable.

In the present case, a so-called single fault of the parking lock valve or the position valve means operating states to which the parking lock valve or the position valve can not be actuated to the required extent by the actuating force due to clamping operating conditions or due to faulty pressure regulators.

From the DE 10 2014 207 797 A1 a transmission device with a hydraulic system is known, which has two hydraulic pumps and allows a demand-based, energy-efficient oil supply of the transmission components.

The present invention has for its object to provide a hydraulic system of an executed with a parking brake device automatic transmission and a method for operating a parking brake device by means of a hydraulic system by means of which unwanted operations of the parking brake device can be avoided and requested operating state change the parking brake device can be implemented to the desired extent.

According to the invention, this object is achieved with a hydraulic system and a method for operating a parking brake device by means of a hydraulic system according to the features of patent claims 1 and 10, respectively.

The hydraulic system according to the invention of an automatic transmission designed with a parking brake device is designed with a parking brake valve which can be precontrolled against a force, to which a main pressure can be applied in a defined operating state range of a position valve. The position valve is against a force Pre-controlled via a feedforward control. A pressure chamber of a parking lock cylinder can be acted upon in a defined operating state range of the parking lock valve for laying out the parking lock device or hydraulically holding the parking brake device in the designed state via the parking lock valve with the main pressure, while the pressure chamber is in a further operating state range of the parking lock valve via this with a non-pressurized area and the parking brake device is convertible into its engaged operating state.

According to the invention, the parking brake valve can be held above a defined pressure threshold of the main pressure and / or an applicable pilot pressure counter to the actuating force in its defined operating state range. The position valve is from a pressure threshold of the applicable pilot pressure of the feedforward control against the force in another operating state range convertible, in which the supply of the main pressure to the parking brake valve is locked in the region of the position valve and the parking lock valve via the position valve with a Vorbefüllventil in connection, which is between the Positioning valve and a non-pressurized area is arranged and whose response limit corresponds to a pressure level in the pressure chamber of the parking lock cylinder, to which the parking brake device is in its inserted state can be transferred.

If the parking brake device is in the designed operating state and a request is made to engage the parking brake device, the parking brake device is in the area of the parking lock valve or in the region of the position valve, in spite of the presence of a single fault. H. the parking lock valve or the position valve clamps in an operating state range which is not pushed against the actuating force, for example due to contamination, in the required extent convertible from its designed operating state into its engaged operating state.

For example, if the positional valve is in its unseated position, the parking lock valve is capable of being reduced to its other operating state range by reducing the pilot pressure and simultaneously decreasing the main pressure applied to a self-holding line of the parking lock valve by deactivating the self-holding of the parking lock valve and the pressure in the pressure space of the parking brake valve Parking lock cylinder via the parking brake valve in the direction of the unpressurized area degradable and the parking brake device in the inserted operating state can be transferred.

Since the pressure connection between the main pressure leading portion of the hydraulic system and the parking lock cylinder via the two independently operable valves, d. H. the parking brake valve and the position valve is carried out, the parking brake device is inserted even with a single error in the parking brake valve. For this purpose, the position valve is to be converted from the pilot pressure of the feedforward control counter to the adjacent actuating force into its further operating state range, in which the connection between the main pressure and the parking brake valve in the region of the positional valve is interrupted. In addition, the parking lock valve is connected in the presence of the position valve in its further operating state range via the position valve with the Vorbefüllventil, whereby the parking lock cylinder via the Vorbefüllventil in the direction of the non-pressurized area is emptied to transfer the parking brake device in its engaged operating condition.

In contrast, the hydraulic system according to the invention provides in the presence of a request for holding the parking brake device in the engaged operating state the advantage that the parking brake device in the presence of a single error in the parking lock valve or the position valve does not accidentally goes into its designed operating state.

Thus, for example, by means of the hydraulic system according to the invention in a clamping operating state of the parking brake valve in its counter to the force undamped position after a restart of a prime mover running with the automatic transmission vehicle powertrain the ability to convict the position valve by appropriately raising the pilot pressure of the pilot control in its other operating state range and a To avoid loading the parking lock cylinder with main pressure and to keep the pressure in the pressure chamber of the parking lock cylinder via the position valve and the downstream Vorbefüllventil at the pressure level at which the parking brake device is in its inserted state transferable or durable. This unintentional design of the parking brake device is reliably avoided in a single error of the parking brake valve.

If, however, in the region of the position valve, a so-called single fault due to a clamping operating state or a failure of the pilot control of the pilot control adjusting pressure regulator, the parking brake device is not designed in an undesired extent in such an operating state of the hydraulic system, since the forwarding of the main pressure in the direction of the parking lock cylinder Area of the parking lock valve, which is located in the parking area locking device in its other operating state area is locked.

If the actuating force acting on the parking brake valve and the actuating force applied to the position valve respectively correspond to a spring force of a spring device of the parking lock valve and of the position valve, the hydraulic system can be operated with little control effort.

If a throttle device is provided between the parking lock valve and the position valve whose minimum flow cross section is smaller than a minimum flow cross section of a line region extending between the parking lock valve and the unpressurised region, it is ensured on the one hand that the hydraulic fluid volume flow introduced into the pressure chamber of the parking lock cylinder is limited when the parking lock device is designed is and the functioning of the hydraulic system affecting pressure drops of the main pressure can be safely avoided. In addition, the dimensioning of the flow cross section of the throttle device and of the flow cross section of the line region extending between the parking lock valve and the depressurized region offers the possibility of determining a malfunction in the area of the parking lock valve. This results from the fact that a taking place during a loading operation of the parking brake device emptying the parking lock cylinder within a shorter emptying time via the parking lock valve in the direction of the non-pressurized area is feasible as this over the positional valve and the Vorbefüllventil comprehensive hydraulic path can be implemented.

Due to the throttle device arranged between the parking lock valve and the position valve, the pushing out of hydraulic fluid from the parking lock cylinder via the position valve and the pre-charge valve takes much longer than the direct shift-out process via the parking lock valve in the direction of the unpressurized area. Detected by the software, the insertion time of the parking brake device starting from the control of the position valve on the pilot pressure of the pilot control to feedback via a parking brake displacement sensor, so it is determined before switching off a drive machine, whether the parking lock valve is stuck in jammed position and thus at a restart of the Drive machine a suitable drive sequence for the position valve feasible. When determining such an error case, for example, it is possible to prohibit a so-called remotest start of a vehicle during which a prime mover is started by remote control when the vehicle is stationary and without a driver in the vehicle, in order to avoid accidental start of a vehicle. A remote start function allows a driver to start the engine via a radio remote control in order to switch certain vehicle systems into operation.

In an advantageous development of the hydraulic system according to the invention, the position valve can be converted into its defined operating state range by means of a pilot pressure and the adjacent actuating force counter to the pilot control, within which the main pressure can be applied via the position valve on the parking lock valve. Thus, in case of failure of the pressure plate or pressure regulator, in the range of the pilot pressure of the pilot control of the position valve is adjustable, the driving mode still maintainable and vehicle availability can be improved if the pressure regulator as a so-called inverse pressure regulator or as a pressure regulator with decreasing current pressure Characteristic is executed.

This results from the fact that then in case of failure of the pressure regulator at the position valve, the maximum pilot pressure is applied, especially as in a power failure of the set in the region of the inverse pressure actuator pilot pressure assumes its maximum value and the position valve is transferred alone against the force in its other operating state range, in which the parking lock valve is connected via the position valve with the Vorbefüllventil and the parking lock cylinder is vented to an undesirable extent. This can be avoided by appropriate application of the further pilot pressure at the position valve with little effort and the parking brake device is still hydraulically durable in designed operating condition. As soon as the further pilot pressure is lowered to a predefined pressure level, the position valve is shifted from the pilot pressure of the pilot control counter to the actuating force, and the parking lock can be transferred to its engaged operating state.

In a structurally simple and operable with little control effort and embodiment of the hydraulic system according to the invention, a ratio between a control surface of a valve spool of the positional valve to which the further pilot pressure can be applied, and a further control surface of the valve spool on which the control pressure of the pilot control can be applied , designed so that the positional valve can be converted into its defined operating state by means of the further pilot pressure which can be applied to the valve slide and the actuating force acting in the same direction on the valve slide against the pilot control pressure of the pilot control that can be applied to the valve slide.

If the positional valve can be acted upon by pilot control pressure exclusively via control pressure lines belonging to pilot control stages or pressure regulators, fluctuations in the course of time will be affected Main pressure is not on the control of the position valve. Such working pressure disturbances or fluctuations in the course of the main pressure are caused, for example, by high leaks of a hydraulic consumer to be supplied with the main pressure.

If a first pressure medium source which can be driven on the input side and a second pressure medium source that can be driven on the output side are provided, wherein a delivery volume of the first pressure medium source can be varied as a function of a pilot pressure, the main pressure can be set over a large operating state range of a vehicle with simultaneously low power losses. Thus, for example, via the transmission output side drivable second pressure medium source of the main pressure during a sail operating state of a vehicle with simultaneously switched off prime mover available. In contrast, the main pressure is generated in the vehicle standstill and switched on the prime mover on the transmission input side drivable first pressure medium source.

In a further advantageous embodiment of the hydraulic system according to the invention, the pressure medium sources each have a pilot-controlled valve means for adjusting the main pressure in order to adjust the main pressure operating state dependent on the respectively required pressure level and at the same time to avoid hydraulic losses.

Is the parking brake valve by means of the pilot pressure, by means of which the delivery volume of the first pressure medium source is variable, and applied in the pressure chamber of the parking lock cylinder pressure against the actuating force in its defined operating state range transferred while the position valve by means of the pilot pressure, by means of which the second pressure medium source associated Valve device against the applied actuating force is vorsteuerbar, and the adjoining actuating force in its defined operating state range convertible, the parking brake device is also during a so-called ECO operating state or ECO mode, during which software the main pressure and a pump flow in the region of the first pressure medium source as energy optimal or be kept to a minimum, safe durable in designed operating condition.

This results from the fact that during the ECO mode, the pump flow of the first pressure medium source is shut off by means of the pilot lock pressure can be applied to the parking lock valve and the parking brake valve is maintained despite reduced main pressure from the pilot pressure against the force in its other operating state range.

In the method according to the invention for operating a parking brake device by means of a hydraulic system described in detail above, in the presence of a request for engaging the parking brake device starting from a designed operating state of the parking brake device, the pilot pressure of the pilot control of the actuating force applied counteracting the positional valve, whereby the parking brake device redundant in their inserted operating state can be transferred is, which simple error in the parking brake valve or in the range of the position valve does not prevent a desired engagement of the parking brake, since the pressure chamber of the parking lock cylinder is then either via the functioning parking lock valve in the required for the insertion of the parking brake device in the direction of the non-pressurized area is vented or the the opposite pressure in the pressure chamber of the parking lock cylinder on the faulty parking lock valve in Richtun g of the shifted over the pilot pressure of the pilot control position valve and from there forwarded in the direction of Vorbefüllventils and degraded there in the direction of the non-pressurized area.

In the presence of a request to engage the parking brake device starting from a designed operating state of the parking brake device are applied in an advantageous variant of the method according to the invention applied to the parking brake valve pilot pressure and optionally applied to the parking lock valve via the position valve main pressure respectively to defined pressure levels, to which the parking brake valve of the attacking force against the pilot pressure and against the pressure between the parking brake valve and the parking lock cylinder in its other operating state range can be transferred. Thus, the parking brake device is inserted even with a detected simple error of the position valve by lowering the main pressure, by means of which the self-holding threshold of the parking brake valve is below, to the desired extent and with little effort.

If the parking lock device is maintained in a designed operating state in the presence of a request for disengagement of the parking brake device via a locking device, while the locking device is deactivated in the presence of a request for engaging the parking brake device, the parking lock device is securely locked even in case of failure of the hydraulic self-maintenance of the parking brake device in designed operating condition and with little effort in their inserted operating condition convertible.

The main pressure is set or maintained in an advantageous variant of the method according to the invention upon detection of a malfunction of the locking device to a pressure level greater than a threshold on which the parking brake device by means of the main pressure in the designed operating state can be transferred or preserved in the designed operating condition.

If the parking brake device in the presence of a request for engaging the parking brake device is maintained in the engaged mode or transferred to the inserted operating state that applied to the position of the valve in the direction of the further operating state range of the positional valve and against the force acting pilot pressure while an actuation of the parking brake valve by the Pilot pressure and the pressure between the parking lock valve and the pressure chamber of the parking lock cylinder counter to the force in the direction of the further operating state range of the parking brake valve is omitted, the parking brake device is held in the inserted operating state or a desired error in the parking brake valve or in the region of the position valve to the extent desired transferred to this.

In an advantageous variant of the method according to the invention, the insertion time of the parking brake device is determined in the presence of a request for engaging the parking brake device starting from a designed operating state of the parking brake device, wherein when determining a loading time greater than a defined period of time an error in the parking lock valve is detected. Thus, for example, during a restart of a prime mover, a suitable drive sequence for the position valve can be provided in order to transfer the parking brake device to the required extent in its inserted or in its designed operating state or in each case to hold in this.

The position valve is to improve vehicle availability in a further advantageous variant of the method according to the invention when the maximum pilot pressure of the pilot control on the positional valve and upon detection of a fault in the range of a pressure regulator, in the region of the pilot pressure of the position valve is adjustable by appropriate application of the further pilot pressure operated against the pilot pressure of the feedforward control in the direction of its further operating state range in order to hold the parking brake device hydraulically in designed operating condition can.

If the parking brake device in the presence of a request for disengaging the parking brake device by applying the pilot pressure on the parking lock valve against the attacking force and by operating the parking brake valve in the direction of its defined operating state range held in its designed operating state, while the position valve by means of the pilot pressure against the force in the direction of its defined Operating state range is controlled, the circuit combination for controlling the position valve and the parking brake valve is specifically used to keep the parking brake during defined operating state progressions redundant in designed operating condition and to prevent collapse of the parking brake device.

An undesirable collapse of the parking brake device is avoided in a further advantageous variant of the method in that the parking brake device in the presence of a request for laying out the parking brake device and an operating state of the first pressure medium source in which the delivery volume of the first pressure medium source is less than a threshold, and a Operating state of the second pressure medium source, in which the flow of the second pressure medium source is greater than a threshold, is held in its designed operating condition that the second pressure medium source associated pilot-operated valve means for setting a main pressure greater than a pressure value with the minimum pilot pressure is applied above the parking brake valve is actuated by the main pressure in the direction of its defined operating state range.

In advantageous developments of the hydraulic system according to the invention, the position valve can be acted upon via a filter with the main pressure, while the parking lock valve is connected via a filter with the parking lock cylinder in combination. This prevents or reduces a dirt entry into the position valve and / or into the parking lock valve with little effort.

In the present case, a pressureless area is understood as meaning a space of the hydraulic system or of an automatic transmission in which ambient pressure prevails.

The term unpressurized is to be expressed in the present case that no force effect arises in the pressure-free region from the ambient pressure, since it acts on all surfaces in all spatial directions.

In addition, in the present case the term main pressure or working pressure is understood below to mean a pressure with which a consumer, for example a hydraulic motor or a hydraulic cylinder is acted upon, which is the consumer of a Hydraulic system is in the area of which the pressure is converted into a force or a torque. In contrast to the main pressure no consumer is supplied with a hydraulic energy under a pilot pressure or a control pressure, but a hydraulic valve is moved or actuated or switched.

Basically, the hydraulic system with both pressure regulators with increasing current-pressure curve or with decreasing current-pressure curve is executable. In the case of pressure regulators with increasing current-pressure characteristic, the adjusted pressure value increases with increasing value of the electric current flowing through the pressure regulator. This means that in the event of a power failure, the set pressure value theoretically drops to zero or ambient pressure. In contrast, the value of the regulated pressure in a pressure regulator with decreasing current-pressure characteristic decreases with increasing current value, so that in the event of a power failure the regulated pressure or pilot pressure assumes its maximum value. The latter feature is relevant, for example, for emergency circuits, in which it must be ensured that certain clutches are kept closed by maintaining the pressurization in case of power failure in the transmission and thus a gear ratio is switched, in which the vehicle remains agile.

Both the features specified in the claims and the features specified in the subsequent embodiments of the subject invention are each suitable alone or in any combination with each other to further develop the subject invention.

Further advantages and advantageous embodiments of the subject invention emerge from the claims and the embodiments described in principle below with reference to the drawings, wherein the same reference numerals are used in the description of the various embodiments in favor of clarity for construction and functionally identical components.

• 1 einen Teil eines Hydrauliksystems eines mit einer Parksperreneinrichtung ausgeführten Automatgetriebes in eingelegtem Betriebszustand der Parksperreneinrichtung;
• 2 eine 1 entsprechende Darstellung des Hydrauliksystems in ausgelegtem Betriebszustand der Parksperreneinrichtung;
• 3 eine 1 entsprechende Darstellung des Hydrauliksystems während eines Einlegevorgangs der Parksperreneinrichtung;
• 4 das Hydrauliksystem gemäß Fig. 1 bei Vorliegen einer Anforderung zum Einlegen der Parksperreneinrichtung;
• 5 das Hydrauliksystem gemäß 1 bei klemmendem Positionsventil bei gleichzeitiger Entlüftung der Parksperreneinrichtung über ein Parksperrenventil;
• 6 das Hydrauliksystem gemäß 1 bei klemmendem Positionsventil und gleichzeitiger Anforderung zum Auslegen der Parksperreneinrichtung;
• 7 das Hydrauliksystem gemäß Fig. 1 während eines Segelbetriebs bei gleichzeitig abgeschalteter Antriebsmaschine sowie einer Fahrzeuggeschwindigkeit größer als eine Schwelle;
• 8 das Hydrauliksystem gemäß 1 bei ausgelegter Parksperreneinrichtung und gesetztem Positionsventil, um ein unbeabsichtigtes Auslegen zu verhindern;
• 9 ein Ablaufdiagramm einer Diagnose der Funktionsweise des Parksperrenventils; und
• 10 ein Ablaufdiagramm einer Überwachung des hydraulischen Selbsthaltes der Parksperreneinrichtung.

It shows:

• 1 a part of a hydraulic system of a running with a parking brake device automatic transmission in engaged operating condition of the parking brake device;
• 2 a 1 corresponding representation of the hydraulic system in interpreted operating condition of the parking brake device;
• 3 a 1 corresponding representation of the hydraulic system during a loading operation of the parking brake device;
• 4 the hydraulic system of Figure 1 in the presence of a request for engaging the parking brake device.
• 5 the hydraulic system according to 1 with clamping position valve with simultaneous ventilation of the parking brake device via a parking lock valve;
• 6 the hydraulic system according to 1 with clamping position valve and simultaneous request to lay out the parking brake device;
• 7 the hydraulic system of Figure 1 during a sailing operation with simultaneously shut down prime mover and a vehicle speed greater than a threshold.
• 8th the hydraulic system according to 1 with the parking brake device and set position valve designed to prevent unintentional deployment;
• 9 a flowchart of a diagnosis of the operation of the parking brake valve; and
• 10 a flow chart of a monitoring of the hydraulic self-holding the parking brake device.

1 shows a part of a hydraulic system 1 an automatic transmission 2 or a dual-clutch transmission. The hydraulic system 1 includes a pumping device 3 with two pump units 4 . 5 , wherein the first pump unit or pressure medium source 4 as adjustable vane pump and the second pump unit 5 or the second pressure medium source is designed as a fixed displacement pump. The first pump unit 4 In the present case, the transmission main pump is coupled to a transmission input shaft (not shown in detail in the drawing) in a manner known per se, and thus from one to the transmission input shaft of the automatic transmission 2 connectable drive machine, preferably an internal combustion engine, can be driven. In contrast, the second pump unit 5 with the transmission output shaft of the automatic transmission 2 coupled, in turn, in a manner known per se with an output of one with the automatic transmission 2 executed vehicle drive train is connectable and can be driven with a drive speed equivalent to the output speed.

A printed page 6 the first pump unit 4 stands with a primary pressure circuit 7 in which a major pressure p_sys or a system pressure is present, which in turn via a vorsteuerbares system pressure valve 8th or a pre-controllable valve device is adjustable. Downstream of the system pressure valve 8th is a likewise controllable valve unit 9 provided, which is a so-called cooling valve. In the in 1 illustrated switching position the valve unit 9 is the primary pressure circuit 7 with another pressure circuit 10 connected, which is a separate low-pressure circuit and via a lubrication spider of Radsatzkühlung and further an all-wheel clutch can be supplied with hydraulic fluid. In another switching position of the valve unit 9 is the primary pressure circuit 7 with an additional pressure circuit 12 connected, over which the two clutches K1 and K2 of the double clutch system of the automatic transmission 2 be acted upon with the operating state dependent respectively required amount of cooling oil.

A printed page 14 the second pump unit 5 is at positive pressure gradient between the pressure side 14 and the primary pressure circuit 7 via a check valve 15 with the primary pressure circuit 7 connected. A pressure of the pressure side 14 the second pump unit 5 is in dependence on another pilot-controlled valve device 17 variable.

In addition, the system pressure is p_sys at a pressure reducing valve 18 in whose area the system pressure p_sys to a defined pressure level of a reducing pressure pressure P_Red limited to pressure regulators EDS1, EDS2, EDS3, EDS4 and EDS 8th is applied. The pressure regulators EDS1 to EDS8 can each be supplied with current, wherein, depending on the particular applied control current and the Reduzierdrucks pressure P_Red in the area of the pressure regulators EDS1 to EDS8 a pilot pressure p_EDS1, p_EDS2, p_EDS3, p_EDS4 or p_EDS8 is set, which can be applied in each case in the manner described in detail below in the range of different valves as pilot pressure.

About the pump device 3 A needs-based hydraulic supply assigned actuators. For example, the two clutches K1 and K2 associated clutch valves 19 . 20 and a parking lock device 21 starting from the primary pressure circuit 7 or the first pump unit 4 over the position valve POSV supplied, if this in the in 1 illustrated switching position or present in the operating state range shown.

During normal operating conditions during which a presently run as an internal combustion engine prime mover with the automatic transmission 2 executed vehicle drive train is switched on and a speed of the transmission input shaft is greater than zero and at the same time a vehicle speed and a drive speed is also greater than zero, the wheelset of the automatic transmission 2 and also the four-wheel clutch, at least starting from the second pump unit 5 over the further pressure circuit 10 supplied with hydraulic fluid. Since the load of the wheelset of the automatic transmission usually increases with increasing vehicle speed, is carried out by the second pump unit 5 , whose pump drive speed or whose flow is proportional to the vehicle speed, automatically in certain operating points a need-based cooling.

Is the prime mover of the vehicle drive train at higher speeds, for example during a sailing operation, switched off and promotes the first pump unit 4 no hydraulic fluid, there is the possibility of the primary pressure circuit 7 over the check valve 15 starting from the second pump unit, which is then driven by the output speed or by a rotational speed equivalent thereto 5 to supply with hydraulic fluid. Will the pressure on the pressure side 14 the second pump unit 5 over the valve device 17 raised, there is the possibility in certain operating points of the automatic transmission 2 or the vehicle drive train designed therewith, a limited functionality of the automatic transmission 2 , For example, a gear tracking, a clutch cooling or acting on the parking brake device 21 with hydraulic fluid, via the second pump unit 5 to maintain.

In terms of the print side 6 the first pump unit 4 is downstream of the position valve POSV a parking lock valve PSV the parking lock device 21 provided, over which a pressure room 22 a parking lock cylinder 23 the parking lock device 21 either with the position valve POSV or a non-pressurized area 24 can be brought into operative connection, the latter operating state of the parking brake valve PSV in 1 is shown.

Generally speaking about the hydraulic system 1 and the valve circuit, a control of the electro-hydraulic parking brake device 21 , which is part of a so-called park-by-wire system, feasible in the manner described in more detail below, during a single fault in the area of the position valve POSV or in the area of the parking lock valve PSV to ensure engagement or disengagement of the parking brake device and beyond either an accidental collapse of the parking brake device 21 or an unintentional layout of the parking brake device 21 to prevent.

When connecting the pressure chamber 22 of the parking lock cylinder 23 with the position valve POSV over the parking lock valve PSV will be in the in 1 shown operating state of the position valve POSV the system pressure p_sys created, wherein above a defined pressure threshold of the system pressure p_sys a parking lock piston 25 the parking lock device 21 against a spring force of a spring device 26 from the in 1 shown position, with the inserted operating state of the parking brake device 21 corresponds to a in 2 shown position is shifted, in turn, with the designed operating state of the parking brake device 21 corresponds. Thus the system pressure works p_sys in the parking lock cylinder 23 as working pressure, as in the parking lock cylinder 23 hydraulic energy is converted into mechanical energy.

In engaged operating state of the parking brake device 21 is a positive connection between a housing side fixed parking pawl and the output side of the automatic transmission 2 before, in the engaged operating state of the parking brake device 21 is held in a known extent rotationally fixed by the parking pawl. When pressurizing the parking lock cylinder 23 is the positive connection of the parking brake device 21 solved what the designed operating state of the parking brake device 21 equivalent. Below an actuation pressure threshold of the pressure in the pressure chamber 22 of the parking lock cylinder 23 becomes the parking lock piston 25 from the spring device 26 starting from the designed operating state of the parking brake device 21 from the in 2 shown position in the direction of 1 shifted position shown, if at the same time an electromagnetically actuated locking device 27 about which the parking brake device 21 is durable in designed operating condition is disabled.

Both the position valve POSV as well as the parking lock valve PSV are each from a spring device 28 respectively. 29 in the in 1 shown operating conditions, as long as the on the position valve POSV applicable pilot pressure p_EDS3 and the parking brake valve PSV against the force of the spring device 29 applicable pilot pressure p_EDS4 the pressure regulator EDS4 are below a defined pressure threshold. In addition, the pilot pressure p_EDS3 is also at the system pressure valve 8th can be applied, while the pilot pressure p_EDS4 in addition to the pilot control of the parking brake valve PSV also for controlling the flow rate of the first pump unit 4 is provided.

The pilot pressure p_EDS8 is in this case the pilot pressure p_EDS3 counteracting the positional valve POSV and in addition to the pilot-operated valve device 17 Can be applied to a distribution of hydraulic fluid in the direction of the lubrication spider and the additional pressure circuit 12 to influence.

The combinatorics of the connection of the three pressure regulators EDS3, EDS4 and EDS8 result in the functional properties of the hydraulic system described in more detail below 1 ,

The parking lock valve PSV and the position valve POSV are arranged in series connection. The position valve POSV is about a filter 30 with the system pressure p_sys provided. Will the parking lock valve PSV from the in 1 shown operating state area in the in 2 transferred shown operating state range, in addition to the pilot pressure p_EDS4 and the pressure between the parking brake valve PSV and the pressure room 22 of the parking lock cylinder 23 equivalent to the pilot pressure p_EDS4 on the parking brake valve PSV at. At correspondingly high pressure values of the pilot pressure p_EDS4 and / or the pressure between the parking brake valve PSV and the parking lock cylinder 23 is a latch of the parking lock valve PSV against the attacking force of the spring device 29 activated.

This version of the parking lock valve PSV As a result, the parking lock valve PSV against the force of the spring device 29 in the in 2 shown operating state range is first transferred from the pilot pressure p_EDS4 and then from this and / or the pressure between the parking brake valve PSV and the parking lock cylinder 23 is held as long as the force resulting from the applied compressive forces is greater than the actuating force of the spring device 29 , In the unswitched operating state of the parking brake valve PSV lies in the pressure room 22 of the parking lock cylinder 23 in each case in the area of the position valve POSV switched through pressure. This is the parking lock valve PSV in the 1 shown operating state range of the position valve POSV the system pressure p-sys on. Will the position valve POSV from the pilot pressure p_EDS3 from the in 1 shown operating state range against the actuating force of the spring device 28 in the in 3 transferred operating state range shown, is the parking brake valve PSV over the position valve POSV with a pre-filling valve 31 connected between the positional valve POSV and a non-pressurized area 32 of the automatic transmission 2 is arranged and its response limit a pressure level in the pressure chamber 22 of the parking lock cylinder 23 corresponds to which the parking brake device 21 in its inserted state can be transferred.

Is the driver side via a selector lever or an equivalent operating element to an operating state of the automatic transmission 2 requested in the automatic transmission 2 a gear ratio for forward drive or reverse drive is to be inserted, or a neutral operating state of the automatic transmission 2 , during which a power flow in the area of the automatic transmission 2 is interrupted, the parking brake device is 21 with perfect functioning of the hydraulic system 1 designed. The above-described operating states of the automatic transmission 2 correspond with selector lever positions or Speed steps D, R or N. In each of the speed steps D, R or N are the clutch valves 19 and 20 as well as the parking lock valve PSV over the position valve POSV to the system pressure line of the hydraulic system 1 Tailored and are via the position valve POSV with the system pressure p_sys applied.

Passes a corresponding driver-side request for inserting the parking brake device 21 , the position valve becomes POSV from the in 1 shown operating state in the in 3 transferred shown operating state range. For this purpose, the pilot pressure p_EDS8 is lowered to zero via the pressure regulator EDS8. Since the pressure regulator EDS8 is designed here as an inverse pressure regulator, this is maximally energized for this purpose. At the same time, the pilot pressure p_EDS3 is raised to a pressure level to which the position valve POSV against the force of the spring device 28 in the in 3 shown operating state range is transferred. Switching the position valve POSV causes the at the parking lock valve PSV applied pressure abruptly drops and the self-holding function of the parking brake valve PSV is deactivated at appropriately adjusted pilot pressure p_EDS4, bringing the parking brake valve PSV from the force of the spring device 29 in the in 1 shown operating state range can be transferred, in which the pressure chamber 22 of the parking lock cylinder 23 over the parking lock valve PSV with the unpressurized area 24 connected is. This in turn causes the pressure in the pressure chamber 22 dismantles and the parking lock piston 25 of the parking lock cylinder 23 with the locking device deactivated 27 in his with the inserted operating state of the parking brake device 21 corresponding and in 1 shown position of the spring device 26 is transferred, bringing the parking brake device 21 is inserted. In each case, a movement of the parking brake piston 25 is monitored via a parking lock sensor, not shown.

The venting path of the pressure chamber 22 over the parking lock valve PSV in the direction of the unpressurized area 24 is in 3 characterized in more detail on the more elaborate lines. By pushing the position valve POSV will be between the positional valve POSV and the parking lock valve PSV as well as to the clutch valves 19 and 20 leading and in 4 Stronger line of the hydraulic system highlighted 1 depressurized or to the pressure level or the response limit of Vorbefüllventils 31 guided. About the pre-filling valve 31 Under operating conditions, only the idling of the clutch K2 prevented. This is also the coupling K1 another pre-filling valve 33 assigned.

In case of a single fault in the area of the parking lock valve PSV or in the area of the position valve POSV and in the presence of a request to engage the parking brake device 21 starting from a designed operating condition to be able to guarantee that the parking brake device 21 according to the requirements, can be transferred to the engaged operating state, is the hydraulic system 1 executed with the redundancy described in more detail below and operated as follows.

Is the position valve POSV due to a clamping operating condition or a failure of the pressure regulator EDS3 not from the in 5 respectively. 6 shown operating state range against the force of the spring device 28 in the in 4 shown operating state range convertible, the latching of the parking brake valve PSV by reducing the pilot pressure p_EDS4 in the area of the pressure regulator EDS4 and simultaneously lowering the system pressure p_sys disabled, so the parking lock valve PSV from the force of the spring device 29 from the in 6 shown operating state area in the in 5 shown operating state range is transferred, in which via the position valve POSV in the area indicated by the stronger stroke guide circumference applied system pressure p_sys in the area of the parking lock valve PSV from the pressure room 22 is disconnected while the pressure chamber 22 over the parking lock valve PSV with the unpressurized area 24 is in operative connection and is vented. In this operating state of the hydraulic system 1 is the parking lock facility 21 depressurized, bringing the parking brake device 21 at the same time disabled locking 27 goes into its inserted operating state.

Because the pressure connection between the system pressure p_sys leading primary pressure circuit 7 and the parking lock cylinder 23 via the two independently operable valves, ie the position valve POSV and the parking lock valve PSV , done, is the parking lock facility 21 even in the presence of a single fault in the parking brake valve area PSV inserted in the requested scope. Clamp the parking lock valve PSV in the 6 shown operating state range, the properly functioning position valve POSV by corresponding actuation via the pilot pressure p_EDS3 in its in 4 shown operating state range transferred, the parking brake valve PSV with the pre-filling valve 31 connected and the parking lock cylinder 31 via the pre-filling valve 31 emptied. One between the position valve POSV and the parking lock valve PSV provided throttle device 34 used when laying out the parking brake device 21 for limiting the while in the pressure room 22 introduced oil flow to avoid system pressure drops.

Furthermore, the design of the hydraulic system provides 1 also the possibility of the parking lock device 21 during defined operating state curves of the automatic transmission 2 or the hydraulic system 1 in the presence of a request to lay out the parking brake device 21 when pre-cleaning a single fault in the area of the parking lock valve PSV or in the area of the position valve POSV to keep in designed operating condition.

If, for example, the operating states D, R, N are requested, during which the parking brake device 21 is designed in error-free operation, and is also no requirement for inserting the parking brake device 21 before, the above-described Schaltungskombinatorik for redundant insertion of the parking brake device 21 in the scope described in detail below also specifically used for the parking brake device 21 keep redundant in certain operating points.

Both the position valve POSV as well as the parking lock valve PSV are each formed with 2 pressure connections, via the on the position valve POSV the pilot pressures p_EDS3 and p_EDS8 can be applied while on the parking lock valve PSV the pilot pressure p_EDS4 and the pressure between the parking brake valve PSV and the parking lock cylinder 23 can be switched on.

As already explained in more detail is the self-holding function of the parking brake valve PSV deactivated when the actuating force of the spring device 29 greater than the resulting from the pressure applied to the parking brake valve pressures resulting restoring forces. Then there is a drop in the parking lock valve PSV and the parking lock valve PSV goes into the example in 5 shown operating state range over.

In the presently considered embodiment of the hydraulic system 1 the holding pressure level of the parking brake valve is above 5 bar, preferably at about 5.5 bar. This during operation of the automatic transmission 2 minimum pressure level of the system pressure p_sys is about 3.5 bar. Will the automatic transmission 2 operated in a so-called ECO mode, an energy consumption of the automatic transmission is attempted 2 to minimize. This is the system pressure p_sys lowered to the minimum pressure level and the delivery volume of the first pump unit 4 also reduced. For this purpose, a flow control valve 35 of the hydraulic system 1 by applying the pilot pressure p_EDS4 of the pressure regulator EDS4 to an adjustable orifice valve 36 sealed off and a lifting ring of the variable displacement pump or the first pump unit 4 pushed away from the maximum stop. In this by the minimum system pressure p_sys and the lowest possible flow in the area of the first pump unit 4 marked ECO mode remains the parking lock valve PSV nevertheless in its shifted, ie in its set position, since during the activated ECO mode on the parking brake valve PSV a correspondingly high pilot pressure p_EDS4 is applied and the parking brake valve PSV from pilot pressure p_EDS4 despite reduced system pressure p_sys against the force of the spring device 29 in the in 6 shown operating state range is transferred. In this operating state of the hydraulic system 1 For example, the energization of a holding magnet of the locking device 27 switched off, as the parking brake device 21 hydraulically maintained in designed operating condition and a single redundancy is ensured. During a further operating state course of the automatic transmission 2 or a vehicle driveline designed therewith, during which a sail operation is activated with the prime mover switched off at the same time, supplies the first pump unit 4 no volume flow.

Since the speed of the output during a sailing operation of a vehicle with simultaneously switched off prime mover is greater than zero and usually greater than a threshold, the hydraulic supply of the hydraulic system takes place 1 during such sailing operation via the second pump unit 5 , wherein the system pressure then in the range of the valve device 17 is adjusted and via the check valve 15 at the position valve POSV is applied. For this purpose, the pressure regulator EDS8 is turned off to the area of the valve device 17 to set the maximum pressure. The valve device 17 operates in this operating state of the hydraulic system as a replacement system pressure valve, which is a replacement system pressure level p_sys provides, which is greater than the holding pressure of the parking brake valve to the self-holding function of the parking brake valve PSV to activate.

Thus, it is ensured during a sailing operation even when the engine is switched off that the parking brake device 21 hydraulically durable in designed operating condition and in addition to the locking device 27 is secured against accidental insertion, and here also at least temporarily energization of the electromagnet of the locking device 27 can be switched off.

The pressure plate EDS4 is ineffective during the last-described operating state course, since the first pump unit 4 not driven by the prime mover. Shortly before a vehicle standstill, for example, at vehicle speeds between 5 and 10 km / h and the flow rate of the second pump unit decreases 5 on a level off that the parking lock valve PSV to maintain the self-holding function additionally starting from the pressure regulator EDS4 to the pilot pressure p_EDS4 is to be acted upon, as the system pressure p_sys then because of the very low flow rate of the second pump unit 5 below the self-holding threshold of the parking lock valve PSV falls.

The supply path of the parking brake device 21 starting from the second pump unit 5 over the check valve 15 and the position valve POSV as well as the parking lock valve PSV is in 7 in turn characterized by the stronger line design closer.

For example, after a restart of the prime mover unintentional interpretation of the parking brake device 21 even in the presence of a hydraulic single fault in the area of the parking lock valve PSV or in the area of the position valve POSV to prevent the hydraulic system 1 operated in the manner described in more detail below.

For example, the driver requests via a selector lever position P an engaged operating state of the parking brake device 21 after a restart of the prime mover and clamps the parking brake valve PSV in deferred position or is the parking lock valve PSV from the force of the spring device 29 from the in 8th shown operating state area not in the in 1 shown operating state range convertible, the position valve POSV by applying a corresponding pilot pressure p_EDS3 by the pressure regulator EDS3 in the in 8th shown operating state range transferred and the connecting line between the primary pressure circuit 7 and the parking lock facility 21 in the area of the position valve POSV separated. An unintentional layout of the parking brake device 21 will despite faulty parking lock valve PSV avoided, because the pressure in the pressure chamber 22 of the parking lock cylinder 23 over the position valve POSV and the pre-fill valve 31 falls to the extent described above.

On the other hand, the position valve clamps POSV in the in 7 shown position or is the position valve POSV from the pilot pressure p_EDS3 not to the desired extent against the force of the spring device 28 umschiebbar, the parking brake device is 21 also not with the system pressure p_sys subjected, whereby an unintentional interpretation of the parking brake device 21 is avoided. In such an operating state of the position valve POSV are also in the direction of the two clutches K1 and K2 leading lines from system pressure p_sys separated, so also a single fault in the range of one of the clutch valves 19 or 20 can not affect an unintentional adhesion.

In case of failure of the pressure regulator EDS_3, which is designed here as an inverse pressure regulator, the position valve POSV subjected to the maximum pilot pressure p_EDS3 and with this against the actuating force of the spring device 28 driven. To be able to maintain vehicle availability even in the event of failure of the pressure regulator EDS3, the position valve is POSV with a corresponding ratio between a control surface 40 a valve spool 41 of the position valve POSV to which the pilot pressure p_EDS8 can be applied, and another control surface 42 of the valve spool 41 at which the pilot pressure p_EDS3 of the pilot control can be applied, carried out that the positional valve POSV by means of the valve spool 41 applicable pilot pressure p_EDS8 and the same direction at the valve spool 41 engaging force of the spring device 28 opposite to the valve spool 41 adjacent pilot pressure p_EDS3 the feedforward control is converted into its defined operating state and the parking brake device 21 hydraulically maintained in designed operating condition. As soon as the pilot control pressure p_EDS8 is reduced in the direction of its minimum pressure value in the region of the pressure regulator EDS8, the positional valve becomes POSV from pilot pressure p_EDS3 to in 8th shown operating state area transferred and the parking brake device 21 is by disabling the self-holding function of the parking brake valve PSV or via the position valve POSV and the pre-fill valve 31 in the extent described above with simultaneously disabled locking 27 inserted.

During a loading operation of the parking brake device 21 and an associated emptying of the parking lock cylinder 23 will the from the pressure room 23 over the parking lock valve PSV discharged volume flow either via the tank pocket of the parking lock valve PSV in the direction of the unpressurized area 24 guided or via the position valve POSV and the pre-fill valve 31 in the direction of the unpressurized area 32 directed. When emptying the parking lock cylinder 23 over the parking lock valve PSV , the position valve POSV and the pre-fill valve 31 is the volume flow through the throttle device 34 to lead whose minimum flow area is smaller than a minimum flow area of the between the parking brake valve PSV and the unpressurized area 24 extending line area. For this reason, the emptying time of the parking lock cylinder 23 via the position valve POSV and the pre-fill valve 31 longer than the emptying time via the parking lock valve PSV in the direction of the unpressurized area 24 , Is during a loading operation of the parking brake device 21 the insertion time of Parking brake device 21 determined by the software on the basis of the control of the pressure regulator EDS3 to the feedback of the parking brake sensor or the parking brake sensor, is already visible before switching off the drive machine, whether the parking brake valve PSV hangs in jammed position and thus at a restart of the prime mover a suitable drive sequence for the position valve feasible.

9 shows a flowchart of a diagnosis of the parking brake valve PSV , which determines whether the operation of the parking brake valve PSV is present in the desired extent.

During a first interrogation step S1, it is checked whether there are valid values on the part of a selector lever, the parking lock sensor, a temperature sensor, an engine speed sensor and the like. If the query result is negative, the diagnosis is ended, while with a positive query result a branch is made to a second query step S2. During the second interrogation step S2, it is again checked whether an engine start phase is currently active. If the query result of the second interrogation step S2 is positive, a branch is made to a first function block FB1, via which the diagnosis of the parking brake valve PSV is activated and the monitoring of the parking brake device 21 is performed via the parking lock sensor.

From the first functional block FB1 is branched to a third query step S3, during which the operation of the parking brake valve is monitored. During the third interrogation step S3 is a proper operation of the parking brake valve PSV determines the diagnostic function of the parking brake valve PSV stopped, whereas in determining a malfunction of the parking brake valve PSV is branched from the third query step S3 to a second function block FB2, on the in the field of transmission control, the faulty function of the parking brake valve PSV is stored to the malfunction during further operation of the automatic transmission 2 as well as the parking lock device 21 to take into account.

If it is determined during the second interrogation step S2 that no engine start phase is currently activated, a branch is made to a fourth interrogation step S4 and it is checked whether the parking brake valve is already functioning properly in the current drive cycle PSV was determined. In this case, under a driving cycle, an operating state progression of the vehicle with the automatic transmission is present 2 understood understood vehicle powertrain, during which both an engine speed of the prime mover and a vehicle speed or an output speed each have exceeded a defined threshold.

If the query result of the fourth interrogation step S4 is positive, the diagnosis function of the parking brake valve becomes PSV terminated, while a negative query result of the fourth interrogation step S4 branches to a third function block FB3, on the diagnosis of the parking brake valve PSV is activated and the Einlegezeit the parking brake device 21 is monitored. Subsequently, during a fifth interrogation step S5, as during the third interrogation step S3, it is checked whether the parking brake valve PSV is faulty or not. If the query result is positive, the parking brake valve diagnostic function becomes PSV terminated, whereas a negative query result of the fifth query step S5 branches to the second function block FB2 and an error entry occurs.

In 10 is another flowchart of a monitoring function of the hydraulic self-holding the parking brake device 21 is shown, wherein during a sixth query step S6 is first checked whether the parking brake device 21 is in a designed operating state. If the query result of the sixth query step S6 is negative, the monitoring function is ended. In contrast, when the query result of the sixth query step S6 is positive, a branch is made to a fourth function block FB4 and the monitoring is activated. The fourth function block FB4 branches to a seventh query step S7. During the seventh monitoring step S7, it is again checked whether the system pressure p_sys is less than a threshold. This is the case, for example, during a sail operation with the prime mover switched off at the same time, during an activated start-stop operation during vehicle standstill or near vehicle standstill and during a so-called car wash operation, during which the parking lock is designed and at the same time the prime mover is switched off. If the query result is negative, an eighth query step S8 is branched, during which it is detected that the hydraulic self-holding of the parking brake device 21 is not activated. From the eighth interrogation step S8, a branch is made to a fifth function block FB5, via which the hydraulic self-hold is reactivated by corresponding actuation of the pressure regulators EDS3 and EDS4.

In addition, the fourth function block FB4 branches to a ninth query step S9, via which it is checked whether the self-holding function of the parking brake valve PSV is activated by corresponding actuation of the pressure regulators EDS3 and EDS4. If the query result of the ninth polling step S9 is positive, no further action takes place, whereas if the polling result of the ninth polling step S9 is negative, a branch is made to a sixth function block FB6, via which a time monitoring is started. Subsequently, the sixth function block FB6 branches to a tenth query step S10. By means of the tenth query step S10 it is checked whether the pressure regulators EDS3 and EDS4 are actuated within a defined monitoring period to such an extent that the hydraulic self-holding of the parking brake device 21 is activated again. If the query result of the tenth query step S10 is positive, no further action takes place. In contrast to this, when the query result of the tenth query step S10 is negative, a branch is made to the fifth function block FB5 and the self-holding function is reactivated. In addition, with a positive query result of the seventh query step S7, a branch is made to a seventh function block FB7, by means of which it is recognized that there is no hydraulic self-holding in the area of the parking brake device.

In a further embodiment of the hydraulic system, the pressure regulator EDS8 is designed as an increasing pressure regulator and the position valve POSV and also the valve device 17 adjusted to the extent required to represent the above-described functionalities of the hydraulic system can.

LIST OF REFERENCE NUMBERS

1

hydraulic system

2

automatic transmission

3

pump means

4

first pump unit

5

second pump unit

6

Pressure side of the first pump unit

7

Primary pressure circuit

8th

System pressure valve

9

valve unit

10

further pressure circuit

12

additional pressure circuit

14

Pressure side of the second pump unit

15

check valve

17

valve means

18

Pressure reducing valve

19

clutch valve

20

clutch valve

21

Parking brake system

22

pressure chamber

23

Parking lock cylinder

24

pressureless area

25

Parking lock piston

26

spring means

27

locking

28

spring means

29

spring means

30

filter

31

pre-filling

32

pressureless area

33

another pre-filling valve

34

throttling device

35

Flow control valve

36

orifice valve

40

control surface

41

valve slide

42

control surface

EDS1 - EDS8

pressure regulator

K1, K2

clutch

p_sys

system pressure

POSV

position valve

PSV

Parking lock valve

S1 - S10

inquiry step

FB1 - FB7

function block

p_EDS1 - p_EDS8

pilot pressure

pressure P_Red

reducing pressure

Claims (18)

Hydraulic system (1) of an automatic transmission (2) with a parking brake device (21) with a parking brake valve (PSV) which can be pre-controlled against a control force, against which a main pressure (p_sys) can be applied in a defined operating state range of a position valve (POSV), which counteracts a control force via a pilot control is carried out vorsteuerbar, wherein a pressure chamber (22) of a parking lock cylinder (23) in a defined operating state range of the parking brake valve (PSV) for laying out the parking brake device (21) or hydraulic holding the parking brake device (21) in the designed state via the parking lock valve ( PSV) with the main pressure (p_sys) can be acted upon while the pressure chamber (22) in a further operating state range of the parking brake valve (PSV) via this with a non-pressurized area (24) is in communication and the parking brake device (21) can be converted into its inserted operating condition, characterized in that the parking brake valve (PSV) above a defined pressure threshold of the main pressure ( p_sys) and / or an applied pilot pressure (p_EDS4) against the actuating force in its defined operating state range is stable and the position valve (POSV) from a pressure threshold of the applicable pilot pressure (p_EDS3) of the precontrol against the actuating force in another operating state range can be transferred, in which the Supply line of the main pressure (p_sys) is locked to the parking brake valve (PSV) in the area of the position valve (POSV) and the parking brake valve (PSV) via the positional valve (POSV) with a Vorbefüllventil (31) is in operative connection between the positional valve (POSV) and a non-pressurized area (32) is arranged and whose response limit corresponds to a pressure level in the pressure chamber (22) of the parking lock cylinder (23), to which the parking brake device (21) can be converted into its inserted state. Hydraulic system after Claim 1 , characterized in that the force acting on the parking brake valve (PSV) and the adjusting force acting on the positional valve (POSV) each correspond to a spring force of a spring device (28, 29) of the parking brake valve (PSV) and the position valve (POSV). Hydraulic system after Claim 1 or 2 , characterized in that between the parking brake valve (PSV) and the position valve (POSV), a throttle device (34) is provided whose minimum flow area is smaller than a minimum flow area of between the parking brake valve (PSV) and the non-pressurized area (24) extending line area , Hydraulic system according to one of Claims 1 to 3 , characterized in that the position valve (POSV) by means of a pilot pressure (p_EDS8) and the applied actuating force against the pilot control in its defined operating state range can be converted, within which the main pressure (p_sys) via the positional valve (POSV) on the parking brake valve (PSV) can be applied , Hydraulic system after Claim 4 , characterized in that a ratio between a control surface (40) of a valve spool (41) of the positional valve (POSV) at which the pilot pressure (p_EDS8) can be applied, and a further control surface (42) of the valve spool (41) on which Pilot pressure (p_EDS3) of the pilot control can be applied, is designed so that the positional valve (POSV) by means of the valve spool (41) can be applied pilot pressure (p_EDS8) and the rectified on the valve spool (41) acting force against the valve spool (41) can be applied pilot pressure (P_EDS3) of the feedforward control can be converted into its defined operating state range. Hydraulic system according to one of Claims 1 to 5 , characterized in that the position valve (POSV) exclusively via control pressure lines associated pressure regulator (EDS3, EDS8) with pilot pressure (p_EDS3, p_EDS8,) can be acted upon. Hydraulic system according to one of Claims 1 to 6 , characterized in that a transmission input side driven first pressure medium source (4) and a transmission output side drivable second pressure medium source (5) are provided, wherein a delivery volume of the first pressure medium source (4) in dependence of a pilot pressure (p_EDS4) is variable. Hydraulic system after Claim 7 , characterized in that the pressure medium sources (4, 5) each have a pilot-controllable valve means (8, 17) for adjusting the main pressure (p_sys) is assigned. Hydraulic system after Claim 8 , characterized in that the parking brake valve (PSV) by means of the pilot pressure (p_EDS4), by means of which the delivery volume of the first pressure medium source (4) is variable, and in the region of the pressure chamber (22) of the parking lock cylinder (23) applied pressure against the force in its defined operating state range can be transferred while the positional valve (POSV) by means of the pilot pressure (p_EDS8), by means of which the second pressure medium source (5) associated valve means (17) is precontrollable against the applied actuating force, and the applied actuating force in its defined operating state range can be transferred , Method for operating a parking brake device by means of a hydraulic system according to one of Claims 1 to 9 , characterized in that in the presence of a request to engage the parking brake device (21) starting from a designed operating state of the parking brake device (21) the pilot pressure (p_EDS3) of the precontrol of the actuating force counteracting the position valve (POSV) is applied. Method according to Claim 10 , characterized in that in the presence of a request to engage the parking brake device (21) starting from a designed operating state of the parking brake device (21) applied to the parking brake valve (PSV) pilot pressure (p_EDS4) and optionally on the parking brake valve (PSV) The main pressure (p_sys) applied via the position valve (POSV) is guided in each case to defined pressure levels, to which the parking brake valve (PSV) of the attacking force against the pilot pressure (p_EDS4) and against the pressure between the parking brake valve (PSV) and the parking lock cylinder (23 ) can be converted into its further operating state area. Method according to Claim 10 or 11 characterized in that the parking brake device (21) in the presence of a request for disengaging the parking brake device (21) via a locking device (27) is kept in a designed operating state, while the locking device (27) in the presence of a request for engaging the parking brake device (21) is deactivated. Method according to Claim 12 characterized in that the master pressure (p_sys) upon detection of a malfunction of the locking device (27) is set or maintained at a pressure level greater than a threshold on which the parking brake device (21) by means of the main pressure (p_sys) in the designed operating state or transferred is durable in the designed operating condition. Method according to one of Claims 10 to 13 , characterized in that the parking brake device (21) in the presence of a request for engaging the parking brake device (21) thereby held in the inserted operating condition or transferred to the inserted operating state that at the position valve (POSV) in the direction of the further operating state range of the positional valve (POSV ) and against the force acting pilot pressure (p_EDS3) is applied, while an actuation of the parking brake valve (PSV) by the pilot pressure (p_EDS4) and by the pressure between the parking brake valve (PSV) and the pressure chamber (22) of the parking lock cylinder (21) opposite Adjustment force in the direction of the further operating state range of the parking brake valve (PSV) is omitted. Method according to one of Claims 10 to 14 characterized in that in the presence of a request for engaging the parking brake device (21) starting from a designed operating state of the parking brake device (21) the loading time of the parking brake device (21) is determined, wherein when determining a loading time greater than a defined period of time an error in the range the parking lock valve (21) is detected. Method according to one of Claims 10 to 15 , characterized in that the positional valve (POSV) at concern of the maximum pilot pressure (p_EDS3) of the pilot control at the position valve (POSV) and upon detection of a fault in the region of a pressure regulator (EDS3), in whose range the pilot pressure (p_EDS3) of the pilot control of the positional valve (POSV) is adjustable, is actuated by appropriate application of a further pilot pressure (p_EDS8) against the pilot pressure (p_EDS3) of the pilot control in the direction of its further operating state range. Method according to one of Claims 10 to 16 , characterized in that the parking brake device (21) in the presence of a request for disengaging the parking brake device (21) by applying the pilot pressure (p_EDS4) on the parking brake valve (PSV) against the attacking force and by operating the parking brake valve (PSV) in the direction of its defined operating state range is maintained in its designed operating state, while the position valve (POSV) by means of the pilot pressure (p_EDS3) is driven against the actuating force in the direction of its defined operating state range. Method according to one of Claims 10 to 17 characterized in that the parking brake device (21) in the presence of a request for laying out the parking brake device (21) and an operating state of the first pressure medium source (4) in which the delivery volume of the first pressure medium source (4) is less than a threshold, and an operating state the second pressure medium source (5), in which the flow rate of the second pressure medium source (5) is greater than a threshold, is thereby maintained in its designed operating state that the pre-controllable valve device (17) assigned to the second pressure medium source (5) is used to set a main pressure ( p_sys) greater than a pressure value with the minimum pilot pressure (p_EDS8) is applied, above which the parking brake valve (PSV) is actuated by the main pressure (p_sys) in the direction of its defined operating state range.

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