DE102021129073A1 - Hydraulic system with differential area piston, two-pressure valve and reversible pump for lubrication and/or cooling as well as for actuation - Google Patents

Abstract

The invention relates to a hydraulic system (1) for actuating an actuator (2) and for supplying a cooling and/or lubricating device (3) of a motor vehicle, with an actuating cylinder (4) and a reversible pump (5), one being displaceable between two end positions accommodated piston (6) of the actuating cylinder (4) is coupled in movement to the actuator (2) and in both end positions with a working port (7a, 7b) of the reversible pump (5) connected hydraulic outlet (8) of the actuating cylinder (4) with the cooling and/or lubricating device (3), and wherein a first working connection (7a) of the reversible pump (5) is connected to a first partial chamber (10a) of the actuating cylinder (4) that acts on a first piston surface (9a) of the piston (6). and a second working port (7b) of the reversible pump (5) is hydraulically connected to a second partial chamber (10b) of the actuating cylinder (4) that acts on a second piston surface (9b) of the piston (6), with the piston (6 ) is designed as a differential area piston and on the other hand there is also a two-pressure valve (11), which two-pressure valve (11) has an inlet (13) connected to a reservoir (12), a first outlet (14 ) and a second output (15) connected to the second working connection (7b).

Description

The invention relates to a hydraulic system for actuating an actuator/switching element and for supplying a cooling and/or lubricating device of a motor vehicle, with an actuating cylinder and a reversible pump, with a piston of the actuating cylinder that is slidably received between two end positions being coupled in motion to the actuating element and one in both End positions (of the piston) connected to a working port of the reversible pump, the hydraulic outlet of the actuating cylinder is connected to the cooling and/or lubricating device, and wherein a first working port of the reversible pump is connected to a first partial chamber of the actuating cylinder, which acts on a first piston surface of the piston, and a second Working connection of the reversible pump is hydraulically connected to a second piston surface of the piston acting on a second piston surface (facing away from/counteracting the first piston surface).

The applicant is already aware of internal prior art that has already been filed with the German Patent and Trademark Office as a German patent application, but has not yet been published. A hydraulic system with a reversible pump is known from this. Several valves are used between a reservoir and the reversible pump. A cooling function as well as the activation of another function can be realized by an actuating cylinder. However, this system assumes that a constant-area piston is used in the actuating cylinder.

However, this has shown that, on the one hand, the actuating cylinder has to be designed to be relatively large and, on the other hand, the overall structure of the hydraulic system is still relatively complex.

It is therefore the object of the present invention to provide a hydraulic system both for actuating a corresponding control element and for supplying a cooling and lubricating device, which is further simplified in its structure and takes up less space.

This is achieved according to the invention in that, on the one hand, the piston is designed as a differential area piston (whereby the first piston area is preferably designed to be smaller than the second piston area) and, on the other hand, there is also a dual-pressure valve, which dual-pressure valve has an inlet connected to a reservoir, one connected to the having a first output connected to the first working connection and a second output connected to the second working connection.

With this design of the hydraulic system, the reversible pump is operated as efficiently as possible. When there is a transition from an adjustment process of the actuator to a supply process for the cooling and/or lubricating device, the direction of delivery of the reversible pump does not need to be reversed. This also means that the hydraulic system is designed to be more durable. Furthermore, the hydraulic system has a structure that is as simple as possible. By designing the piston as a differential surface piston, the actuating cylinder can also be made significantly more compact.

Further advantageous embodiments are claimed with the dependent claims and explained in more detail below.

Accordingly, it is also advantageous if the two-pressure valve can only be moved to a first position, in which the input and the first output are connected to one another, while the second output is separated from the input, and to a second position, in which the input and the second Output are connected together while the first output is disconnected from the input, is switchable/adjustable. This further simplifies the construction of the two-pressure valve.

The design of the two-pressure valve is also further simplified if the two-pressure valve is designed to automatically adjust/switch over as a function of a pressure difference between the two outlets.

In this regard, it is also expedient if the two-pressure valve has two closing bodies each cooperating with a valve seat.

If the closing bodies are rigidly connected to one another by means of a continuous coupling rod, the two-pressure valve is designed to be as durable as possible.

If, on the other hand, the closing bodies are each connected to a (separate, separate) rod, with the (two) rods being dimensioned in such a way that they abut/are supported on one another in the respective position of the two-pressure valve, the two-pressure valve can in turn be used more variably.

In addition, it is advantageous if the reversible pump, the piston and the two-pressure valve are matched to one another in such a way that when the reversible pump is operated in a first delivery direction (preferably the first direction of rotation with Vor (e.g. a pump rotor/rotary pump) the first subchamber is filled with hydraulic medium via the first working connection, while the two-pressure valve assumes its second position, and after the reversible pump has reached the second end position, it maintains its first conveying direction while supplying the cooling and/or lubricating device .

Accordingly, it is also expedient if the reversible pump, the piston and the dual-pressure valve are matched to one another in such a way that when the reversible pump is operated in a second conveying direction (preferably second direction of rotation if a pump rotor is provided), the second subchamber is filled with hydraulic medium via the second working connection , while the two-pressure valve assumes its first position, and after reaching the first end position, the reversible pump, while supplying the cooling and/or lubricating device, maintains its second conveying direction. This results in a particularly efficient operation of the reversible pump.

It is therefore also advantageous if the reversible pump, the piston and the two-pressure valve are matched to one another in such a way that when the reversible pump is operated in the first delivery direction, the first partial chamber is supplied with a first partial quantity of hydraulic medium ( is filled via the first working connection of the reversible pump), while the two-pressure valve assumes its second position, so that a second subset of the hydraulic medium conveyed out of the second partial chamber flows through the two-pressure valve in the direction of the reservoir. This also results in a particularly efficient operation of the reversible pump.

Accordingly, it is also advantageous if the reversible pump, the piston and the dual-pressure valve are matched to one another in such a way that when the reversible pump is operated in the second delivery direction, the second subchamber via the first working port is filled with hydraulic fluid conveyed out of the first subchamber (via the second working port the reversing pump) is filled while the two-pressure valve assumes its first position, so that further hydraulic medium is pumped from the reservoir (via the reversing pump) through the two-pressure valve into the second subchamber. This also results in a particularly efficient operation of the reversible pump.

The structure of the hydraulic system is further simplified if the outlets of the two-pressure valve and the working connections of the reversible pump are hydraulically connected to one another directly/permanently, i.e. without the interposition of additional elements such as valves.

In the same way, it is also expedient if the partial spaces of the actuating cylinder and the working connections of the reversible pump are hydraulically connected to one another directly/permanently, that is to say without the interposition of additional elements such as valves.

In other words, according to the invention, an actuator (hydraulic system) with a differential area piston, a two-pressure valve and a reversing pump is designed for cooling and actuation. Since the volume of hydraulic medium that is shifted from one side to the other in the piston is not balanced, it is proposed to use a two-pressure valve. The working connections (of the reversible pump to the reservoir) are never closed together.

The invention will now be explained in more detail below with reference to figures.

• 1 eine schematische Darstellung eines erfindungsgemäßen Hydrauliksystems nach einem bevorzugten Ausführungsbeispiel, wobei ein Gesamtaufbau des Hydrauliksystems gut zu erkennen ist,
• 2 eine schematische Darstellung des Hydrauliksystems, ähnlich zur 1, wobei eine Reversierpumpe zur Verschiebung eines Kolbens eines Betätigungszylinders in Richtung einer ersten Endstellung in einer ersten Förderrichtung betrieben wird,
• 3 eine weitere Darstellung des Hydrauliksystems, ähnlich zu 2, wobei die Reversierpumpe zur Verschiebung des Kolbens in Richtung einer zweiten Endstellung nun in einer zweiten Förderrichtung betrieben wird,
• 4 eine weitere Darstellung des Hydrauliksystems, ähnlich zu 2, wobei die Reversierpumpe wiederum in der ersten Förderrichtung betrieben wird, nun jedoch der Kolben bereits in seiner zweiten Endstellung angelangt ist, sodass ein erster Arbeitsanschluss der Reversierpumpe über einen ersten Teilraum des Betätigungszylinders mit einer Kühl- und Schmiereinrichtung hydraulisch verbunden ist,
• 5 eine weitere Darstellung des Hydrauliksystems, ähnlich zur 3, wobei die Reversierpumpe wiederum in der zweiten Förderrichtung betrieben wird, nun jedoch der Kolben bereits in seiner ersten Endstellung angelangt ist, sodass ein zweiter Arbeitsanschluss der Reversierpumpe über einen zweiten Teilraum des Betätigungszylinders mit der Kühl- und Schmiereinrichtung hydraulisch verbunden ist,
• 6 eine Detailansicht des in den 1 bis 5 eingesetzten Zweidruckventils im Bereich seiner beiden Ventilsitze und der damit zusammenwirkenden Schließkörper, wobei die Schließkörper jeweils mit einer separaten Stange verbunden sind, sowie
• 7 eine Detailansicht eines Zweidruckventils gemäß einer alternativen Ausführung, wobei die beiden Schließkörper im Vergleich zu 6 durch eine gemeinsame, durchgängige Koppelstange miteinander verbunden sind.

Show it:

• 1 a schematic representation of a hydraulic system according to the invention according to a preferred embodiment, wherein an overall structure of the hydraulic system is clearly visible,
• 2 a schematic representation of the hydraulic system, similar to the 1 , wherein a reversible pump is operated to move a piston of an actuating cylinder in the direction of a first end position in a first conveying direction,
• 3 another representation of the hydraulic system, similar to 2 , wherein the reversible pump is now operated in a second conveying direction to move the piston in the direction of a second end position,
• 4 another representation of the hydraulic system, similar to 2 , wherein the reversible pump is again operated in the first delivery direction, but now the piston has already reached its second end position, so that a first working connection of the reversible pump is hydraulically connected to a cooling and lubricating device via a first subchamber of the actuating cylinder,
• 5 another representation of the hydraulic system, similar to the 3 , The reversible pump is again operated in the second conveying direction, but now the piston has already reached its first end position, so that a second working connection of the reversible pump has a second partial space of the actuating cylinder is hydraulically connected to the cooling and lubricating device,
• 6 a detailed view of the in the 1 until 5 used dual-pressure valve in the area of its two valve seats and the cooperating closing body, wherein the closing body are each connected to a separate rod, and
• 7 a detailed view of a two-pressure valve according to an alternative embodiment, wherein the two closing bodies compared to 6 are connected to each other by a common, continuous coupling rod.

The figures are only of a schematic nature and serve exclusively for understanding the invention. The same elements are provided with the same reference numbers.

With 1 an overall structure of a hydraulic system 1 according to the invention according to a preferred exemplary embodiment can be seen clearly. The hydraulic system 1 is preferably used in a drive train of a motor vehicle. The hydraulic system 1 is preferably used both for actuating/adjusting/switching an actuator 2, which is designed, for example, as part of a parking lock/parking lock actuating mechanism, and for supplying a cooling and lubricating device 3.

The hydraulic system 1 has an actuating cylinder 4 . This hydraulic actuating cylinder 4 in turn typically has a housing 20 within which (in a hydraulic chamber) a piston 6 is slidably guided. The piston 6 is between a first end position, as shown in 1 can be seen, and a second end position, as shown in 4 is recognizable, movable. The piston 6 divides the hydraulic chamber of the housing 20 (by means of its head area 22) into a first partial chamber 10a and a second partial chamber 10b. The partial spaces 10a, 10b consequently act hydraulically during operation on mutually opposite piston surfaces 9a, 9b of the piston 6/head region 22.

It can also be seen that the piston 6 is designed as a differential area piston. The two piston surfaces 9a, 9b are therefore of different sizes. In this embodiment, that first piston surface 9a is made smaller than the second piston surface 9b. This is due in particular to the fact that the piston 6 has a piston rod 21 which extends out of the housing 20 on one side. The piston rod 21 directly adjoins the head area 22 (seen in a displacement direction of the piston 6 ).

The piston rod 21 protrudes from the housing 20 and is coupled to a switching mechanism 23 outside of the housing 20 . The switching mechanism 23 is further connected to the actuator 2 . As already mentioned, the actuator 2 can preferably be used to engage and disengage a parking lock and/or to shift and/or engage and disengage gears of a transmission.

It is also illustrated that the actuator 2 can be fixed by a locking unit 24 . This means that the piston 6 can also be locked indirectly in its respective end position.

The hydraulic system 1 also has a reversible pump 5 . A reversible pump 5 is to be understood as a pump that operates both in a first delivery direction, i.e. to build up pressure/exhaust hydraulic medium on the part of its first working connection 7a, and in a second delivery direction, i.e. to build up pressure/exhaust hydraulic medium on the part of its second working connection 7b is adjustable. The reversible pump 5 is preferably designed as a rotary pump that can be reversed in its direction of rotation (delivery direction).

It can be seen that the first working connection 7a is hydraulically connected directly (i.e. without the interposition of further valves/blocking elements) to the first subchamber 10a and the second working connection 7b directly (ie without the interposition of further valves/blocking elements) to the second subchamber 10b is hydraulically connected. With a corresponding operation of the reversible pump 5 in the first conveying direction ( 2 ) the piston 6 is pushed in the direction of the second end position by the pressurization of the first subchamber 10a, the second subchamber 10b being connected to the second working port 7b, which is then designed as the suction port of the reversible pump 5. Since the first sub-chamber 10a is smaller than the second sub-chamber 10b, a partial quantity of hydraulic medium is returned in the direction of a reservoir 12 at the same time.

When the reversible pump 5 is operated in the second delivery direction, which is opposite to the first delivery direction, the second partial chamber 10b is in turn supplied with hydraulic medium via the second working connection 7b, while the first partial chamber 10a is connected to the first working connection 7a, which then acts as the suction connection of the reversible pump 5 ( 3 ). As a result, the piston 6 is pushed in the direction of its first end position.

Furthermore, the actuating cylinder 4 is connected to the hydraulic chamber/housing 20 centrally between the end positions of the piston 6 sen hydraulic outlet 8 on. The hydraulic outlet 8 is further connected directly to the cooling and lubricating device 3 during operation. That cooling and lubricating device 3 is preferably used in a transmission and/or an electric axle of a motor vehicle.

Furthermore, the hydraulic system 1 has a two-pressure valve 11 according to the invention. The two-pressure valve 11 has an input 13 connected directly to the reservoir 12 and two outputs 14 , 15 . A first outlet 14 is connected immediately/directly (i.e. without the interposition of further valves/blocking elements) to the first working port 7a, whereas a second outlet 15 is directly/directly (ie without the interposition of further valves/blocking elements) connected to the second working port 7b .

It is according to the 2 until 5 to recognize that the two-pressure valve 11 is designed such that it occupies either a first position or a second position. In the first position, the first outlet 14 is connected to the first working connection 7a, while the second outlet 15 is separated from the inlet 13. In the second position, the second outlet 15 is connected to the inlet 13, while the first outlet 14 is separated from the inlet 13.

Furthermore, in connection with the 6 and 7 shown that the internal structure of the two-pressure valve 11 is in principle different executable.

In 6 are two closing bodies 17a, 17b, which cooperate in the respective first and second position with a valve seat 16a, 16b (while separating the input 13 from the respective output 14 or 15), can be supported on one another via two separate rods 19a, 19b.

In 7 On the other hand, the closing bodies 17a, 17b are connected to one another via a common coupling rod 18.

In 2 the volume flows in the hydraulic system 1 and through the two-pressure valve 11 can be seen in the first conveying direction of the reversible pump 5 (first direction of rotation). In this first conveying direction, it can be seen that the reservoir 12 flows through the dual-pressure valve 11 from the direction of the suction area (second working connection 7b) of the reversible pump 5 . This first conveying direction serves to move the piston 6 (from the first end position) in the direction of its second end position.

In 2 it can thus be seen that the flow through the two-pressure valve 11 is realized from the actuating cylinder 4 into the reservoir 12, which enables the use of the differential area cylinder (actuating cylinder 4)/the piston 6 designed as a differential area piston. The closing of the two-pressure valve 11 on the (first) side of the desired pressure build-up (on the side of the first working port 7a connected to the first outlet 14) automatically ensures that the second side (on the side of the second working port 7b connected to the second outlet 15) is opened and remains open so that the excess hydraulic medium / fluid can flow out of the larger volume (second partial space 10b compared to the first partial space 10a).

In 3 the reversible pump 5 is set to deliver the hydraulic medium in a second delivery direction and consequently serves to move the piston 6 (from the second end position) in the direction of its first end position.

In the 4 and 5 it can be seen that during cooling/lubricating in both conveying directions/directions of rotation of the reversible pump 5, the two-pressure valve 11 is flowed through in the usual way (as soon as the piston 6 has reached its respective end position). In other words, in at least one position of the two-pressure valve 11, the flow is reversed when the function changes from “piston movement” to “cooling” without the delivery direction of the reversible pump 5 changing.

The difference between the two in the 6 and 7 shown variants of the two-pressure valve 11 is that according to the 7 (with fixed coupling rod 18) and tensile forces to close the sealing seat / valve seat 16a, 16b can be transmitted. 6 (with two separate rods 19a, 19b), however, shows the possibility that both sealing seats / valve seats 16a, 16b can be open. Depending on the boundary conditions, one or the other version can be advantageous.

Thus, in the implementation of the hydraulic system 1 according to the invention, the reversible pump 5, the piston 6 and the dual-pressure valve 11 are matched to one another in such a way that when the reversible pump 5 is operated in a first conveying direction, the first subchamber 10a is filled with hydraulic medium via the first working port 7a while the two-pressure valve 11 assumes its second position, and after reaching the second end position the reversible pump 5, while supplying the cooling and lubricating device 3, maintains its first conveying direction. When filling the first sub-chamber 10a, the hydraulic medium previously contained in the second sub-chamber 10b is partly supplied directly to the first sub-chamber 10a by means of the reversible pump 5; another part of the hydraulic medium is fed from the second subchamber 10b to the reservoir 12 (due to the smaller size of the first partial space 10a compared to the second partial space 10b). Finally, when the first partial chamber 10a is completely filled and the piston 6 has reached its second end position, the hydraulic outlet 8 is connected (via the first partial chamber 10a) to the first working connection 7a, so that when the reversible pump 5 continues to be driven in the first conveying direction, the cooling - And lubricating device 3 is supplied with hydraulic fluid from the reservoir 12.

Conversely, the reversible pump 5, the piston 6 and the two-pressure valve 11 are also matched to one another in such a way that when the reversible pump 5 is operated in a second delivery direction, the second partial chamber 10b is filled with hydraulic medium via the second working connection 7b, while the two-pressure valve 11 is in its first position occupies, and after reaching the first end position, the reversible pump 5, while supplying the cooling and / or lubricating device 3, maintains its second conveying direction. The hydraulic medium that is additionally required due to the difference in size between the partial spaces 10a and 10b is introduced from the reservoir 12 additionally/at the same time.

In other words, according to the invention, a two-pressure valve 11 and a reversing pump 5 are used for the direct actuation of a differential area piston (piston 6). The differential area piston releases a cooling oil connection (hydraulic connection 8 to the cooling and lubricating device 3) in its (two) end positions. At the same time, the piston 6 enables an actuator function (actuation of an actuator 2).

In at least one situation, the flow through the two-pressure valve 11 is contrary to the usual direction. The unusual flow occurs when the piston 6 moves. The unusual flow occurs when the smaller effective area (first piston area 9a) of the piston 6 is pressurized that the direction of rotation of the pump (reversible pump 5) changes.

Reference List

1

hydraulic system

2

actuator

3

Cooling and/or lubricating device

4

actuating cylinder

5

reversible pump

6

Pistons

7a

first working port

7b

second working port

8th

hydraulic outlet

9a

first piston surface

9b

second piston surface

10a

first subspace

10b

second subspace

11

dual pressure valve

12

reservoir

13

Entry

14

first exit

15

second exit

16a

first valve seat

16b

second valve seat

17a

first closing body

17b

second closing body

18

connecting rod

19a

first rod

19b

second rod

20

Housing

21

piston rod

22

header area

23

switching mechanism

24

locking unit

Claims (10)

Hydraulic system (1) for actuating an actuator (2) and for supplying a cooling and/or lubricating device (3) of a motor vehicle, with an actuating cylinder (4) and a reversible pump (5), with a piston (6 ) of the actuating cylinder (4) is movably coupled to the actuator (2) and a hydraulic outlet (8) of the actuating cylinder (4) connected in both end positions to a working connection (7a, 7b) of the reversible pump (5) to the cooling and/or lubricating device (3), and wherein a first working connection (7a) of the reversible pump (5) is connected to a first partial chamber (10a) of the actuating cylinder (4) acting on a first piston surface (9a) of the piston (6) and a second working connection (7b) of the reversible pump (5) is hydraulically connected to a second partial chamber (10b) of the actuating cylinder (4) acting on a second piston surface (9b) of the piston (6), characterized in that on the one hand the piston (6) is designed as a differential area piston and, on the other hand, a dual-pressure valve (11) is also present, which dual-pressure valve (11) has an input connected to a reservoir (12). gear (13), a first output (14) connected to the first working connection (7a) and a second output (15) connected to the second working connection (7b). Hydraulic system (1) according to claim 1 , characterized in that the two-pressure valve (11) exclusively in a first position in which the inlet (13) and the first outlet (14) are connected to each other, while the second outlet (15) is separated from the inlet (13), and can be switched into a second position in which the input (13) and the second output (15) are connected to one another, while the first output (14) is separated from the input (13). Hydraulic system (1) according to claim 1 or 2 , characterized in that the two-pressure valve (11) is designed to be automatically adjustable as a function of a pressure difference between the two outlets (14, 15). Hydraulic system (1) according to one of Claims 1 until 3 , characterized in that the two-pressure valve (11) has two closing bodies (17a, 17b) each cooperating with a valve seat (16a, 16b). Hydraulic system (1) according to claim 4 , characterized in that the closing bodies (17a, 17b) are rigidly connected to one another by means of a continuous coupling rod (18). Hydraulic system (1) according to claim 4 , characterized in that the closing bodies (17a, 17b) are each connected to a rod (19a, 19b), the rods (19a, 19b) being dimensioned such that they rest against one another in the respective position of the two-pressure valve (11). Hydraulic system (1) according to one of Claims 1 until 6 , characterized in that the reversible pump (5), the piston (6) and the two-pressure valve (11) are matched to one another in such a way that when the reversible pump (5) is operated in a first conveying direction, the first partial chamber (10a) via the first working connection (7a) is filled with hydraulic medium while the two-pressure valve (11) assumes its second position, and after the second end position has been reached, the reversible pump (5) maintains its first conveying direction while supplying the cooling and/or lubricating device (3). Hydraulic system (1) according to one of Claims 1 until 7 , characterized in that the reversible pump (5), the piston (6) and the two-pressure valve (11) are matched to one another in such a way that when the reversible pump (5) is operated in a second conveying direction, the second partial chamber (10b) via the second working connection (7b) is filled with hydraulic medium while the two-pressure valve (11) assumes its first position, and after the first end position has been reached, the reversible pump (5) maintains its second conveying direction, supplying the cooling and/or lubricating device (3). Hydraulic system (1) according to one of Claims 1 until 8th , characterized in that the reversible pump (5), the piston (6) and the two-pressure valve (11) are matched to one another in such a way that when the reversible pump (5) is operated in the first conveying direction, the first partial chamber (10a) via the first working connection (7a) is filled with a first partial quantity of hydraulic medium conveyed out of the second partial chamber (10b), while the two-pressure valve (11) assumes its second position, so that a second partial quantity of the hydraulic medium conveyed out of the second partial chamber (10b) fills the two-pressure valve (11) flows through in the direction of the reservoir (12). Hydraulic system (1) according to one of Claims 1 until 9 , characterized in that the outlets (14, 15) of the two-pressure valve (11) and the working connections (7a, 7b) of the reversible pump (5) are directly hydraulically connected to one another and/or the partial spaces (10a, 10b) of the actuating cylinder (4) and the working connections (7a, 7b) of the reversible pump (5) are directly hydraulically connected to one another.

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