DE102023121096A1 - Hydraulic unit for a drive train of a motor vehicle - Google Patents

Abstract

The invention relates to a hydraulic unit (10), in particular for the drive train of a motor vehicle, with a hydraulic pump (22), a supply output (34) and an actuation output, characterized in that a base plate (12) is provided, which preferably consists of plastic and in which a housing (24) for the hydraulic pump (22) is integrated, wherein at least one actuator (32, 34) is arranged on the base plate (12), which is connected to the actuation output, and wherein the base plate (12) is designed as a transmission cover with a sealing surface (16) which is designed to come into contact with a transmission housing (14).

Description

The invention relates to a hydraulic unit, in particular for the drive train of a motor vehicle, with a hydraulic pump, a supply output and an actuation output.

It is known to use a single hydraulic unit both for the lubrication or cooling of components and for the hydraulic actuation of actuators. In a first operating state, the hydraulic unit supplies hydraulic fluid for the purpose of cooling and/or lubrication via the supply output to a transmission and/or an electric motor, and in a second operating state, the hydraulic unit supplies the hydraulic fluid via the actuation output to a hydraulic actuator. This can actuate a clutch, a transmission actuator or any other component that is actuated with hydraulic pressure.

An example of a hydraulic unit of the type mentioned above can be found in the DE 10 2018 007 459 A1 .

From the DE 10 2018 102 690 A1 A cover for a gearbox is known on which various functional components are arranged, for example a pump that is switched on when required.

The object of the invention is to further develop a hydraulic unit of the type mentioned at the outset in such a way that a high integration density is possible.

To achieve this object, according to the invention, a hydraulic unit of the type mentioned at the outset is provided with a base plate, which preferably consists of plastic and in which a housing for the hydraulic pump is integrated, wherein at least one actuator is arranged on the base plate, which is connected to the actuation output, and wherein the base plate is designed as a gearbox cover with a sealing surface that is designed to come into contact with a gearbox housing. The invention is based on the basic idea of integrating all the components into the base plate that are required so that, on the one hand, a lubricant or coolant flow can be provided continuously via the supply output (at least essentially) and, if required, a pressure fluid flow can be released via the actuation output, with which an actuator can be actuated (in these phases the coolant flow is briefly interrupted). By integrating it into the base plate, fluid channels can be made within the base plate, so that no external lines are required, and, on the other hand, the components can be arranged partly on the gearbox side and partly outside the gearbox in a space-saving manner.

“Integrated into the base plate” here means that the corresponding component is either made in one piece with the base plate or is directly attached to another component that is integrated into the base plate or is directly attached to it, for example by being firmly screwed.

The base plate is preferably made of plastic. Alternatively, other materials are also possible, such as aluminum or aluminum alloys.

According to one embodiment of the invention, a second actuation output is provided so that a second actuator can be actuated in addition to a first actuator.

The actuator can be locked in two actuation positions and has an exposed actuation slide that can be brought into engagement with an actuation element on the transmission side. Such an actuator can be used in particular to switch a claw clutch, with which, for example, an electric motor can be coupled to or decoupled from the drive train.

The actuator can have two guide housings that are screwed to the base plate and between which the actuating slide is exposed. This makes it possible to pre-assemble the actuator. When the actuator is then mounted on the base plate, it is automatically connected to the corresponding fluid channels, so that the overall assembly effort is minimized.

The actuator can also be a short-stroke actuator, in particular a concentric clutch actuator whose actuation direction is parallel to the plane of extension of the base plate. With such an actuator, friction clutches can be switched in a compact structure.

The actuator can have an actuator housing with several mounting holes, by means of which the actuator can be supported on the gearbox side. In this way, the reaction torque of the actuator can be absorbed directly by the clutch to be actuated, so that the base plate is not or only slightly loaded.

A hydraulic pump housing and/or electrical connectors can be integrated into the base plate, thus avoiding the effort required for separate assembly of these components.

According to one embodiment of the invention, a filter for hydraulic fluid is integrated into the base plate so that the hydraulic pump can draw in fluid directly from the interior of the transmission housing. No further assembly steps are necessary once the base plate with the hydraulic pump and the filter has been mounted on the transmission housing.

The filter can have a filter housing on the base plate side and a filter cover connected to the filter housing, which is screwed, welded or clipped. The filter cover, which is separate from the filter housing, makes it easier to attach a filter element inside the filter housing.

Further aspects of the invention are explained below.

The supply output and the actuation output can be connected to an output of the hydraulic pump, with a switching valve arranged between the supply output and the pump output. The hydraulic pump is always operated in the same direction of rotation and the operating state is changed using the switching valve. If hydraulic fluid is to be fed to a lubrication or coolant system via the supply output, the switching valve is open so that the volume flow delivered by the pump is discharged through the supply output. The pump's delivery pressure, which is essentially the same as the pressure at the supply output, is present at the actuation output. However, this pressure is comparatively low so that the actuator connected to the actuation output is not actuated regardless of its specific design. If the actuator is to be switched from a first position to a second position, the switching valve is switched to a closed position so that the supply output is closed. The entire delivery flow of the pump is therefore directed to the actuation output in order to switch the actuator from one position to another. This can be used, for example, to shift a transmission or close a clutch. Depending on the pressure required, the pump speed can be temporarily increased.

Overall, the hydraulic unit has a high energy efficiency because the hydraulic fluid can be delivered to the supply outlet without losses; no valve needs to be actively kept in a certain state and there is no component in the flow path that leads to increased flow resistance.

According to one embodiment of the invention, the actuation output can be connected directly to the output of the pump, resulting in a very cost-effective construction.

According to one embodiment of the invention, a second actuation output is provided, with a second switching valve being arranged between the second actuation output and the output of the pump. This makes it possible to control two actuators via the actuation side of the pump without requiring a great deal of additional construction effort.

The second switching valve is preferably a normally closed valve so that the hydraulic unit for the first actuation output normally operates in the same way as before. Only when the second actuator is to be controlled is the second switching valve opened so that hydraulic fluid can be delivered via the second actuation output.

Preferably, a pressure sensor is associated with the second actuation output so that precise feedback is available about a suitable point in time at which the second switching valve can be closed again.

If a second switching valve is provided, a pressure relief valve is preferably also provided which connects the downstream side of the pump to the downstream side of the first switching valve, more precisely a point between the outlet of the pump and the switching valve to the downstream side of the first switching valve. The pressure relief valve prevents an excessively high pressure from building up on the discharge side of the pump in a state in which the two switching valves are closed, which could damage one of the switching valves.

According to one embodiment, a suction connection is provided that can be connected to a storage tank. This results in a small volume of the hydraulic unit and a high level of flexibility, since the storage tank can be designed depending on external specifications.

The hydraulic pump can be designed as a single-flow pump, resulting in a simple structure. In principle, however, multi-flow pumps can also be used.

The hydraulic pump is preferably a positive displacement pump, in particular a gerotor pump, a vane pump or a gear pump, all of which have a high degree of efficiency with a small installation volume.

The hydraulic unit can be part of an assembly, with the supply output a lubricant line is connected and an actuator is connected to the actuation output, whereby the actuator can be locked in at least one actuation position. Since the actuator can be locked, it can be locked in a position set by the actuation pressure, so that the pump is then operated with a delivery pressure that is set with regard to other requirements, for example for the lubrication system. The delivery pressure of the pump does not have to be matched to the actuator in order to hold it in its actuation position, for example; this is ensured by the locking mechanism, for example a latching magnet.

Preferably, the actuator can be locked in its two actuating positions so that the actuator, after it has been adjusted to a desired position, can be locked there and remains there regardless of the delivery pressure.

According to one embodiment, the actuator connected to the second actuation output can be a short-stroke actuator, in particular a concentric clutch actuator, which can be used to close and open a friction clutch.

According to a further development of the invention, a pressure accumulator is provided, which is arranged in particular between the second switching valve and the actuator. This compensates for any pressure loss via the second switching valve, so that the second actuator remains closed for comparatively long periods of time.

The hydraulic pump can be operated reversibly and have two pump connections that act as a suction and a pressure connection depending on the direction of rotation. The hydraulic unit has at least one suction inlet for sucking in hydraulic fluid, with a suction line section running from the suction inlet to each of the pump connections and a check valve blocking in the direction of the suction inlet being arranged in each of the suction line sections. Starting from a first pump connection, a first pressure line runs to a lubricant connection of the hydraulic unit, with a check valve blocking in the direction of the pump connection being arranged in the first pressure line. Starting from a second pump connection, a second pressure line leads to an actuator connection of the hydraulic unit, with the second pressure line being free of valves.

Because the second pressure line is free of valves, the design of the hydraulic unit is particularly simple and cost-effective.

A further advantage is that in an operating state of the hydraulic unit in which the second pump connection of the reversible hydraulic pump serves as a suction connection, a negative pressure is generated at the actuator connection. This improves the reaction time of a connected actuator. In particular, resistance caused by the inertia of the hydraulic fluid is reduced. Furthermore, the negative pressure ensures that air in the line can escape via the reversible hydraulic pump and thus simultaneously vents the pressure line.

The reversible hydraulic pump is, for example, a rotary vane pump, a gerotor pump or a gear pump. Such pumps are simply constructed and can work equally efficiently in both pumping directions.

The reversible hydraulic pump, for example, has an electric motor. This has the advantage that the flow rate of hydraulic fluid required for the respective task of gear lubrication or clutch operation can be adjusted by simply controlling the speed of the electric motor.

The hydraulic unit can be part of an assembly that also has a clutch actuator that is connected to the actuator port of the hydraulic unit. In such an assembly, the hydraulic unit can be used both for transmission lubrication and for clutch actuation.

According to one embodiment, the clutch actuator is a one-way hydraulic piston that works against a return spring. In addition to a negative pressure generated at the actuator connection in a reversible pump, the return spring helps to ensure that the clutch actuator returns quickly after actuation and a connected clutch therefore opens quickly.

Preferably, a locking bolt is provided which interacts with the hydraulic piston. The locking bolt serves to lock the clutch actuator in an actuated position or in an open position. This means that the clutch actuator can be held in an actuated position even if the second pump connection serves as a suction connection and there is a negative pressure at the actuator connection. The clutch actuator can also be reliably held in an open position.

A magnetic coil can be assigned to the locking bolt. The magnetic coil enables an actuation mechanism of the locking bolt to be easily che way. In particular, electronic control of the locking bolt is possible.

The assembly includes, for example, a claw clutch that can be operated by the clutch actuator. A claw clutch has a simple design and is particularly robust. However, other types of clutches are also possible.

An oil cooler is preferably arranged in the pressure line that runs to the lubricant connection. This improves the cooling effect of the hydraulic oil.

According to one embodiment, a bypass to the oil cooler is provided, with an overpressure or pressure limiting valve blocking in the direction of the pump connection being arranged in the bypass. The additional bypass can limit the pressure acting in the oil cooler, since when the pressure is sufficiently high, the overpressure or pressure limiting valve in the bypass opens and hydraulic oil also reaches the lubricant connection via the bypass.

• - 1 eine Draufsicht auf ein erfindungsgemäßes Hydraulikaggregat;
• - 2 eine Seitenansicht des Hydraulikaggregats von 1;
• - 3 eine Unteransicht des Hydraulikaggregats von 1;
• - 4 eine perspektivische Draufsicht auf das Hydraulikaggregat von 1;
• - 5 eine weitere perspektivische Ansicht des Hydraulikaggregats von 1;
• - 6 eine perspektivische Unteransicht des Hydraulikaggregats von 1;
• - 7 in einer perspektivischen Ansicht ein erfindungsgemäßes Hydraulikaggregat zusammen mit einem Getriebe;
• - 8 in einer weiteren perspektivischen Ansicht die Baugruppe aus Hydraulikaggregat und Getriebe von 7;
• - 9 schematisch eine erste Ausgestaltung des Hydraulikaggregats der 1 bis 6;
• - 10 schematisch eine zweite Ausgestaltung des Hydraulikaggregats der 1 bis 6;
• 11 schematisch eine dritte Ausgestaltung des Hydraulikaggregats der 1 bis 6;
• 12 die Ausgestaltung von 11, wobei sich das Hydraulikaggregat in einem ersten Betriebszustand befindet,
• 13 die Ausgestaltung von 11, wobei sich das Hydraulikaggregat in einem zweiten Betriebszustand befindet.

The invention is described below with reference to two embodiments shown in the accompanying drawings, in which:

• - 1 a plan view of a hydraulic unit according to the invention;
• - 2 a side view of the hydraulic unit of 1 ;
• - 3 a bottom view of the hydraulic unit of 1 ;
• - 4 a perspective view of the hydraulic unit of 1 ;
• - 5 another perspective view of the hydraulic unit of 1 ;
• - 6 a perspective bottom view of the hydraulic unit of 1 ;
• - 7 in a perspective view, a hydraulic unit according to the invention together with a transmission;
• - 8 in another perspective view the assembly of hydraulic unit and gearbox of 7 ;
• - 9 schematically a first embodiment of the hydraulic unit of the 1 to 6 ;
• - 10 schematically a second embodiment of the hydraulic unit of the 1 to 6 ;
• 11 schematically a third embodiment of the hydraulic unit of the 1 to 6 ;
• 12 the design of 11 , wherein the hydraulic unit is in a first operating state,
• 13 the design of 11 , whereby the hydraulic unit is in a second operating state.

In the 1 to 6 a hydraulic unit 10 according to the invention is shown, which is designed as a unit integrated on a base plate 12.

The base plate 12 serves to form an opening in a gear housing 14 shown schematically here (see 2 ). Accordingly, the base plate forms a gear cover.

The base plate 12 is essentially flat and made of plastic. It has a sealing surface 16 which is intended to come into contact with the gear housing 14. In the embodiment shown, the sealing surface 16 is provided with a circumferential seal 18.

As an alternative to plastic, the base plate can also be made of aluminum or an aluminum alloy.

Along its edge, the base plate 12 has several fastening openings 20 with which it can be screwed to the gear housing 14.

A hydraulic pump 22 is integrated into the base plate 12, from which the 1 to 6 only a pump housing 24 can be seen, which is closed by a cover 26.

The pump housing 24 is here designed as one piece with the base plate 12, while the cover 26 is screwed to the pump housing 24.

The hydraulic pump 22 is a pump driven by an electric motor, for example a rotary vane pump, a gear pump or a gerotor pump.

The hydraulic pump 22 sucks in hydraulic fluid through a filter 28 which is integrated with the base plate 12.

A switching valve 30 is arranged on the base plate 12, with which the operation of the hydraulic unit 10 can be switched between a supply of one or more actuators 32, 34, which will be explained later, and the fluid delivery to a supply outlet 36.

The supply outlet 36 serves to deliver a comparatively large fluid flow, which is under a comparatively low pressure, to a gearbox or other components that need to be cooled and/or lubricated. These can be bearings, friction clutches or electric motors.

The actuator 32 has an actuating slide 40 which is guided in two guide housings 42 so that it can be moved between two positions. The two guide housings 42 are mounted on the base plate, for example screwed there, so that internal pistons can be supplied with fluid. This allows the actuating slide to be moved between its two end positions.

Also integrated into the base plate 12 is a magnetic coil 44 with which the actuating slide 40 can be locked in its respective end position.

The actuator 34 here is a concentric clutch actuator, i.e. a short-stroke actuator which is mounted in such a way that its actuation direction extends parallel to the plane in which the base plate 12 is located.

Furthermore, a switching valve 50 is integrated into the base plate 12, with which the actuator 34 can be controlled.

The actuator 34 has several fastening openings 35 on the outside with which it can be supported on the transmission side.

Also integrated is a pressure sensor 52, which monitors the pressure when the clutch assigned to the actuator 34 is closed.

Finally, the hydraulic unit 10 is provided with various connectors 60 to which complementary connectors of a wiring harness can be connected, with which the various components of the hydraulic unit 10 can be controlled.

In the 7 and 8 the hydraulic unit 10 is shown schematically in interaction with various components which are arranged inside the transmission of the transmission housing 14.

On the one hand, the actuator 34 can be seen, which interacts with a clutch (not shown in detail here). On the other hand, an actuating element 70 can be seen, which engages in the actuating slide 40 of the actuator 32.

In 9 A hydraulic unit 110 is shown, which is integrated into the base plate of the embodiment of the 1 to 6 can be integrated.

The hydraulic unit 110 has a hydraulic pump 112 and a drive device 114 for the hydraulic pump 112.

The hydraulic pump can be designed as a positive displacement pump. Particularly suitable designs are gear pumps, vane pumps or gerotor pumps. The drive device 114 is preferably an electric motor.

The hydraulic unit 110 has a suction connection 116 which is connected to a reservoir 118. This is a pump sump inside the transmission housing.

A filter 120 is provided between the suction connection 116 and the suction inlet of the hydraulic pump 112.

The hydraulic unit 110 has a supply output 122 corresponding to the 1 to 6 known supply outlet 36 and an actuation outlet 124. The supply outlet 122 serves to lubricate a gear (not shown here) or to cool a clutch (not shown here) or an electric motor (not shown here). A cooler 126 and a bypass 128 can therefore be provided outside the hydraulic unit 110 before the hydraulic fluid delivered by the hydraulic pump 112 reaches the lubrication points or the clutch. These components are designated here with S and K.

Generally speaking, the supply outlet is used to provide a volume flow of hydraulic fluid over longer periods of time. For lubrication, the volume flow is always required when components are rotating. For cooling, the volume flow is always required when waste heat is generated. In both cases, the volume flow is required over a period of several seconds up to a continuous volume flow.

The actuation output 124 serves to provide a volume flow for actuating an actuator 150 provided on the base plate. This corresponds to the actuator 32 of the embodiment of the 1 to 6 In contrast to the volume flow provided at the supply output 122, the volume flow at the actuation output 124 is only required for a very short period of time.

The supply output 122 and the actuation output 124 are connected together to a Pressure outlet 130 of the hydraulic pump 112 is connected. Downstream of a branching point 132, a switching valve 134 is arranged in the line that leads to the supply outlet 122.

The switching valve 134 can be designed as a solenoid-operated slide valve.

It serves to open or close the connection between the pressure outlet 130 of the hydraulic pump 112 and the supply outlet 122 of the hydraulic unit 110.

The connection between the pressure output 130 of the hydraulic pump 112 and the actuation output 124 is designed without valves or other active components. The actuation output 124 is therefore directly connected to the pressure output 130.

In the embodiment shown here, the actuator 150 is a parking lock actuator 150 that can be switched or actuated from a state with an activated parking lock to a state with a deactivated parking lock, and vice versa.

The parking lock actuator 150 is urged into a first actuating position by a spring 152. The parking lock actuator 150 can be locked in this actuating position. A magnetically actuated locking device 154 can be used for this purpose.

If a sufficiently high pressure is applied to the actuation output 124, the parking lock actuator is adjusted from the first actuation position to a second actuation position. The parking lock actuator 150 can also be locked in the second actuation position. A second magnetically actuated locking device 156 can be used for this purpose.

Position sensors may be provided to monitor the positions of the parking lock actuator 150, but these are not shown here for the sake of clarity.

A second actuator 150' can be controlled in parallel to the parking lock actuator 150 (or, if necessary, a third, fourth, ...). A switching valve 153 is assigned to this.

The hydraulic unit 110 can be operated in two states. In a so-called supply state, the hydraulic pump 112 serves to convey the hydraulic fluid from the supply outlet 122 to lubrication or cooling points in the drive train of the motor vehicle. For this purpose, the switching valve 134 is open.

In this state, the delivery pressure is usually so low that the spring 152 holds the parking lock actuator 150 in the first actuation position. In addition, the parking lock actuator 150 can be locked in the first actuation position by means of the first locking device 154, so that even a briefly increased delivery pressure of the hydraulic pump 112 does not result in the first parking lock actuator 150 being switched to the second actuation position.

If the parking lock actuator 150 is to be switched to the second actuation position, the switching valve 134 is closed and the first locking device 154 is opened. At the same time, the speed of the hydraulic pump 112 is increased so that the delivery pressure increases. This switches the parking lock actuator to the second actuation position. In this position, it can be locked by means of the second locking device 156.

The speed of the hydraulic pump 112 can then be reduced again and the switching valve 134 is opened again. This supplies the lubrication or coolant system with hydraulic fluid again. The brief interruption of the supply to the lubrication or coolant system during switching of the parking lock actuator 150 does not affect the lubrication and cooling.

A pressure relief valve 157 is arranged between the two fluid channels outside the supply outlet 122 and the actuation outlet 124.

If the parking lock actuator 150 is to be returned to the first actuation position, the locking device 156 is opened so that the spring 152 returns the parking lock actuator 150 to the first actuation position. The hydraulic fluid displaced in the process is discharged via the supply outlet 122. If the parking lock actuator 150 is in the first actuation position, it is locked there by means of the locking device 154.

The position of the actuator 150 can be monitored by means of suitable position sensors.

It is also possible to operate the hydraulic pump with a higher volume flow and to deliver this completely to the supply output 122 when the actuator 150 is locked, if this is appropriate in a certain operating state.

In 10 a hydraulic unit according to a second embodiment is shown, which is also integrated in the base plate of the embodiment of the 1 to 6 can be integrated. For the design of the 9 known components are the The same reference numerals are used and reference is made to the first embodiment.

The difference between the design of the 9 and 10 is that in the design of the 10 two actuation outputs 124, 124' are provided on the hydraulic unit 110. These are used to actuate different actuators.

Similar to the first embodiment, an actuator 150 is connected to the actuation output 124, which can be locked in its two actuation positions by means of two locking devices 154, 156. In contrast to the first embodiment, the actuator 150 is designed here as an actuating cylinder for actuating a claw clutch. However, with regard to the manner in which it is actuated by the hydraulic unit 110, there are no structural differences to the actuator 150 of the first embodiment.

A second actuator 151 is connected to the second actuation output 124', which is a short-stroke actuator 151, in particular a concentric clutch actuator 151. It serves to actuate a friction clutch from an open to a closed position and corresponds to the actuator 34 of the embodiment of the 1 to 6 .

A second switching valve 160 is provided within the hydraulic unit 110 and is arranged between the branch to the first actuation output 124 and the second actuation output 124'. It can open and close the connection between the pressure output 132 and the second actuation output 124'.

The second switching valve 160 can be a solenoid-operated ball valve.

A pressure sensor 162 is arranged between the second switching valve 160 and the second actuating output 124', which is connected to a control system not shown here.

Finally, a pressure relief valve 164 is arranged within the hydraulic unit 110, which connects the hydraulic branch between the two switching valves 134, 160, i.e. downstream of the pressure outlet 130, with the downstream side of the first switching valve 134.

Assuming that the second switching valve 160 is closed, the lubrication and coolant system connected to the supply output 122 and the actuator 150 (and any further actuators 150') connected to the first actuation output 124 can be operated or actuated in the same manner as in the first embodiment.

If the second actuator 151 is to be actuated, the second switching valve 160 is opened and the first switching valve 134 is closed. This causes the hydraulic oil delivered to the second actuator 151, which closes the clutch assigned to it. The first actuator remains in its current actuating position due to the locking devices 154, 156.

The closing of the clutch can be monitored by the pressure detected by the pressure sensor 162.

When the clutch is closed, the second switching valve 160 can be closed again. This "blocks" the second actuator 151 so that the clutch remains closed. In this state, the supply output 122 and the actuation output 124 can again be supplied with hydraulic fluid in the desired manner.

A pressure accumulator 166 is arranged in the hydraulic branch "behind" the second actuation output, which ensures that the pressure is maintained when the second switching valve 160 is closed and the clutch is kept in a closed state, even if the switching valve 160 has a slight leak. If the pressure sensor 162 detects a pressure below a predetermined threshold value, the second switching valve 160 can be opened briefly so that the pressure in the branch of the second actuator 151 is increased again.

The pressure relief valve 164 ensures that the pressure in the branch between the two switching valves 134, 160 cannot become excessively high, for example when the hydraulic pump 112 operates with the switching valves 134, 160 closed and the first actuator 150 locked.

In principle, it is also possible to operate the two actuators 150, 151 simultaneously.

In 11 A third embodiment of the hydraulic unit is shown, which is integrated into the base plate of the embodiment of the 1 to 6 can be integrated.

11 shows a hydraulic unit 212, which is used for hydraulic clutch actuation and transmission lubrication.

For this purpose, the hydraulic unit 212 can be used in a first operating state for clutch actuation and in a second operating state condition for gear lubrication, as explained below.

In particular, hydraulic fluid can be conveyed to a lubricant connection 214 or to an actuator connection 216 by means of the hydraulic unit 212. The lubricant connection 214 corresponds to the supply connection 36 of the embodiment of the 1 to 6 .

The hydraulic unit 212 has a reversible hydraulic pump 218 with two pump connections 220, 222. The pump connections 220, 222 can act as a suction and a pressure connection depending on the direction of rotation of the reversible hydraulic pump 218.

The reversible hydraulic pump 218 is associated with an electric motor 224 which can drive it in both operating directions.

For example, the reversible hydraulic pump 218 is a rotary vane pump, a gerotor pump or a gear pump.

The hydraulic unit 212 has a suction inlet 226 for sucking in hydraulic fluid.

A filter 227 is provided at the suction inlet 226, which corresponds to the filter 28 of the embodiment of the 1 to 6 corresponds.

In the exemplary embodiment, a reservoir 228 is provided which contains hydraulic fluid, with the suction inlet 226 being arranged in the reservoir 228. The reservoir is designed as a pump sump inside the transmission.

Starting from the suction inlet 226, a suction line section 230, 232 runs to each of the pump connections 220, 222.

Starting from a first pump connection 220, a first pressure line 234 runs to the lubricant connection 214 of the hydraulic unit 212.

Starting from a second pump connection 222, a second pressure line 236 leads to the actuator connection 216 of the hydraulic unit 212.

In each of the suction line sections 230, 232, a check valve 238, 240 (or generally an overpressure or pressure relief valve) is arranged which blocks in the direction of the suction inlet 226.

A further check valve 242 (or generally a pressure relief or pressure limiting valve) is arranged in the pressure line 234 running from the first pump connection 220 to the lubricant connection 214, which blocks in the direction of the pump connection 220.

The pressure line 236 leading from the second pump connection 222 to the actuator connection 216, however, is free of valves.

In the illustrated embodiment, a clutch actuator 244 is connected to the actuator connection 216. This corresponds to the actuator 32 of the embodiment of the 1 to 6 .

The clutch actuator 244 is a one-way hydraulic piston 246 that works against a return spring 247.

The hydraulic piston 246 is linearly guided in a housing 249.

A clutch 248 of an assembly 210 comprising a hydraulic unit and a clutch can be actuated by means of the clutch actuator 244, the clutch in the exemplary embodiment being a claw clutch. For this purpose, the hydraulic piston 246 is operatively connected to a clutch sleeve 250 of the clutch 248.

The hydraulic piston 246 can be locked by means of a locking pin 252 which cooperates with the hydraulic piston 246.

For the purpose of locking, the locking pin 252 engages in radial notches 254, 256 of the hydraulic piston 246.

The notches 254, 256 are arranged such that when the locking pin 252 engages in the first notch 254, the hydraulic piston 246 is held in an actuating position in which the clutch 248 is closed, and when the locking pin 252 engages in the second notch 256, the hydraulic piston 246 is held in an opening position in which the clutch 248 is opened.

A solenoid coil 258 is associated with the locking pin 252. When the solenoid coil 258 is energized, the locking pin 252 can be raised to release the hydraulic piston 246.

In order to achieve particularly efficient cooling during transmission lubrication, an oil cooler 262 is arranged in the pressure line 234, which runs to the lubricant connection 214.

In addition, a bypass 264 to the oil cooler 262 is provided, wherein a check valve 266 blocking in the direction of the pump connection 220 is arranged in the bypass 264.

The bypass 264 makes it possible to deliver a larger volume flow of hydraulic fluid to the lubricant connection 214 than would be possible via the oil cooler 262.

The check valve 266 prevents hydraulic fluid from flowing back from the outlet of the oil cooler 262 to the pump connection 220.

12 illustrates the assembly 210, wherein the hydraulic unit 212 is operated in a first operating state for clutch actuation.

A direction of rotation of the reversible hydraulic pump 218 is illustrated by an arrow 260.

In this case, the first pump connection 220 acts as a suction connection and the second pump connection 222 acts as a pressure connection.

The fluid conveying lines are in 12 shown in greater detail for illustrative purposes.

The reversible hydraulic pump 218 sucks in hydraulic fluid via the first suction line section 230 and delivers it to the actuator connection 216, so that a fluid pressure at the actuator connection 216 increases.

The check valve 240 in the second suction line section 232, which blocks in the direction of the suction inlet 226, prevents hydraulic fluid from being fed directly back into the reservoir 228.

As soon as the locking pin 252 releases the hydraulic piston 246, the hydraulic piston, which is in 10 shown in its open position, into the operating position (see 13 ) and closes the clutch 248.

13 illustrates the assembly 210, wherein the hydraulic unit 212 is operated in a second operating state for transmission lubrication and/or transmission cooling.

In this case, the second pump connection 222 acts as a suction connection and the first pump connection 220 acts as a pressure connection.

Also in 13 The fluid-conveying lines are shown in greater detail for illustration purposes.

The reversible hydraulic pump 218 sucks in hydraulic fluid via the second suction line section 232 and conveys it to the lubricant connection 214, from where the hydraulic fluid reaches a gear to be lubricated.

The check valve 238 in the first suction line section 230, which blocks in the direction of the suction inlet 226, prevents hydraulic fluid from being fed directly back into the storage tank 228.

At the same time, due to the fact that there are no valves in the second pressure line 236, hydraulic fluid is sucked in from the pressure line 236, so that a negative pressure is created at the actuator connection 216. This reduces resistance when the hydraulic piston 246 is returned, which increases the reaction speed and the pressure line 236 and the hydraulic piston 246 are vented via the reversible hydraulic pump 260.

This means that as soon as the locking pin 252 releases the hydraulic piston 246 held in the actuating position, it can be moved particularly quickly into its opening position by the restoring force of the return spring 247. In this way, the opening behavior of the clutch 248 is improved.

The invention is not limited to the embodiments and configurations shown. On the base plate of the 1 to 6 all features of the designs of the 9 to 13 can be arranged individually or in combination, as long as this is in line with the task to be solved, namely to increase the integration density on the base plate and at the same time to achieve variable functionality of the hydraulic unit.

QUOTES INCLUDED IN THE DESCRIPTION

This list of 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 accepts no liability for any errors or omissions.

Cited patent literature

• DE 10 2018 007 459 A1 [0003]
• DE 10 2018 102 690 A1 [0004]

Claims (10)

Hydraulic unit (10), in particular for the drive train of a motor vehicle, with a hydraulic pump (22), a supply output (34) and an actuation output, characterized in that a base plate (12) is provided, which preferably consists of plastic and in which a housing (24) for the hydraulic pump (22) is integrated, wherein at least one actuator (32, 34) is arranged on the base plate (12), which is connected to the actuation output, and wherein the base plate (12) is designed as a transmission cover with a sealing surface (16) which is designed to come into contact with a transmission housing (14). hydraulic unit according to claim 1 , characterized in that a second actuation output is provided. Hydraulic unit according to one of the preceding claims, characterized in that the actuator (32) can be locked in two actuating positions and has an exposed actuating slide (40) which can be brought into engagement with a transmission-side actuating element (70). Hydraulic unit according to one of the preceding claims, characterized in that the actuator has two guide housings (42) which are screwed to the base plate (12) and between which the actuating slide (40) is exposed. Hydraulic unit according to one of the preceding claims, characterized in that the actuator is a short-stroke actuator (34), in particular a concentric clutch actuator, the actuating direction of which is parallel to the plane of extension of the base plate (12). hydraulic unit according to claim 5 , characterized in that the actuator has an actuator housing with a plurality of fastening openings (35) by means of which the actuator (34) can be supported on the transmission side. Hydraulic unit according to one of the preceding claims, characterized in that a housing (24) of the hydraulic pump (22) is integrated into the base plate (12). Hydraulic unit according to one of the preceding claims, characterized in that electrical connectors (60) are integrated into the base plate (12). Hydraulic unit according to one of the preceding claims, characterized in that a filter (28) for hydraulic fluid is integrated into the base plate (12). hydraulic unit according to claim 9 , characterized in that the filter (28) has a filter housing on the base plate side and a filter cover connected to the filter housing, which is screwed, welded or clipped.

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