DE102020126811A1 - Hydraulic system with pressure accumulator designed for actuation; as well as drive unit - Google Patents

Abstract

The invention relates to a hydraulic system (1) for a motor vehicle, with a pump (2) reversible in its conveying direction, a cooling and / or lubricating device (4) coupled to a first connection (3) of the pump (2), one via a Line arrangement (5) and a first valve (6) with a second connection (7) of the pump (2) and a parking lock actuation device (8) that can be coupled via the line arrangement (5) and the first valve (6) likewise to the second connection (7) ) the pump (2) couplable clutch actuation device (9), wherein a pressure accumulator (10) by means of a second valve (11) on a first line section (12) of the line arrangement (5) running between the first valve (6) and the parking lock actuation device (8) ) and / or can be coupled to a second line section (13) of the line arrangement (5) running between the first valve (6) and the clutch actuation device (9). The invention also relates to a drive unit (20) with this hydraulic system (1).

Description

The invention relates to a hydraulic system for a motor vehicle, with a pump that is reversible in its conveying direction, a cooling and / or lubricating device coupled to a first connection of the pump, a parking lock actuation device that can be coupled to a second connection of the pump via a line arrangement and a first valve, and also a Clutch actuating device which can also be coupled to the second connection of the pump via the line arrangement and the first valve.

In principle, the applicant is aware of the internal state of the art, which has not yet been published, but has already been filed with the German Patent and Trademark Office as a German patent application. This prior art bears the file number DE 10 2018 112 670.0 with filing date 28 May 2018. Further state of the art is provided by the German patent application with the file number, which has also been submitted but not yet published DE 10 2019 100 872.7 known with registration date January 15, 2019. Hydraulic systems are therefore already known in principle in which reversing pumps are used for the optional supply of cooling / lubrication and for actuating a clutch or a parking lock.

However, it has turned out to be a disadvantage of these designs known from the prior art that the corresponding hydraulic systems are in need of further improvement in terms of their efficiency. This is due to the fact that the pump actuator in the form of the pump is operated in the so-called "cooling mode" for the majority of the operating time, whereby the delivery direction of the pump has to be reversed relatively often, primarily due to the existing leakage on the part of the clutch actuation device and the parking lock actuation device the clutch actuation device and the parking lock actuation device have to be supplied with hydraulic fluid again. In principle, this process takes a relatively long time delay due to the switching of the pump. There is also the disadvantage that cooling or lubrication cannot take place during the actuation of the clutch or the parking lock. This problem is further exacerbated if the so-called holding magnet of the parking lock fails, since in this case a permanent supply of hydraulic pressure / hydraulic medium is required. Furthermore, if the corresponding first valve fails, the parking lock or the clutch can no longer be actuated at all in certain operating states. At the same time, the quickest possible emergency closing of the clutch should be possible.

It is therefore the object of the present invention to eliminate the disadvantages known from the prior art and to provide a hydraulic system which has an improved degree of efficiency and ensures a coolant and lubricant supply with as few interruptions as possible.

This is achieved according to the invention in that a pressure accumulator can be coupled by means of a second valve to a first line section of the line arrangement running between the first valve and the parking lock actuation device and / or to a second line section of the line arrangement running between the first valve and the clutch actuation device.

By providing this pressure accumulator and the corresponding second valve, the parking lock actuation device and / or clutch actuation device is supplied with a constant pressure over a period of time that is as long as possible. This makes it possible to switch the pump over with regard to its delivery direction significantly less often. This significantly increases the efficiency of the hydraulic system.

Further advantageous designs are claimed with the subclaims and explained in more detail below.

With regard to the connection of the pressure accumulator / the second valve, it has also proven to be advantageous if a charging line, which connects the second connection of the pump to the pressure accumulator in at least one operating state, runs between the first valve and the second valve / the first valve with connects to the second valve. As a result, the pressure accumulator is charged as simply as possible, regardless of the actuation state of the parking lock actuation device and the clutch actuation device.

Furthermore, it is advantageous if the first valve is designed such that in its first valve position it connects the second connection of the pump to the second line section, while the first line section is separated from the second connection of the pump.

Furthermore, the first valve is designed such that it is in its second Valve position connects the second connection of the pump to the first line section, while the second line section is separated from the second connection of the pump.

In addition, it is preferred if the first valve is designed such that in its third valve position it connects the second connection of the pump to the charging line, while the first line section and the second line section are separated from the second connection of the pump.

It is also advantageous if the second valve is designed in such a way that in its first valve position it connects the pressure accumulator to the first line section, while the second line section and the charging line are separated from the pressure accumulator.

Accordingly, it is also preferred if the second valve is designed such that in its second valve position it connects the pressure accumulator to the charging line, while the first line section and the second line section are separated from the pressure accumulator.

In addition, it is advantageous if the second valve is designed such that in its third valve position it connects the pressure accumulator to the second line section, while the first line section and the charging line are separated from the pressure accumulator.

It is also advantageous if the parking lock actuation device has a holding magnet which can be controlled in such a way that it holds the parking lock actuation device in an open position when the motor vehicle is in operation (and consequently the corresponding parking lock is opened / unlocked). This makes the parking lock actuation device as easy to implement as possible.

In addition, it is advantageous if the second line section is connected to a drain valve, via which drain valve it can be connected to a reservoir.

The pump is typically used in such a way that when it is operated in a first conveying direction it conveys hydraulic medium via the first connection to the cooling and / or lubricating device and when it is driven in a second conveying direction it conveys hydraulic medium via the second connection to the first valve promotes.

Furthermore, it is useful if the first valve and / or the second valve are / is designed as a directional valve (as well as a solenoid valve).

The invention also relates to a drive unit for a motor vehicle, with a hydraulic system according to the invention according to at least one of the embodiments described above.

In other words, a hydraulic system, preferably for a twin drive system, with a pressure accumulator for actuation is thus provided according to the invention. According to the invention, the reserve tank / pressure accumulator is used to control a parking lock and a separating clutch (K0) in order to reduce the switching frequency of the electronic pump actuator (EPA). The hydraulic pressure required to control the parking lock and separating clutch K0 can be taken from the accumulator.

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

• 1 ein schematisches Schaltbild eines erfindungsgemäßen Hydrauliksystems nach einem bevorzugten Ausführungsbeispiel, sowie
• 2 eine schematische Darstellung einer das Hydrauliksystem nach 1 aufweisenden Antriebseinheit.

Show it:

• 1 a schematic circuit diagram of a hydraulic system according to the invention according to a preferred embodiment, and
• 2 a schematic representation of the hydraulic system according to 1 having drive unit.

The figures are merely of a schematic nature and serve exclusively for the understanding of the invention.

As at first in 2 you can see the hydraulic system 1 preferably for use in a drive unit 20th of a hybrid motor vehicle. In further versions is the hydraulic system 1 also used in other drive units, for example in drive units of purely electrically powered motor vehicles. The drive unit 20th exhibits next to an internal combustion engine 21st a first electric motor 22nd , a second electric motor 23 and one between the first electric motor 22nd and the second electric motor 23 arranged disconnect clutch 24 on. The second electric motor 23 is then in a typical way with wheels 25th of the motor vehicle further coupled. The hydraulic system according to the invention 1 serves to operate the disconnect clutch 24 as well as for cooling and lubricating various components of the drive unit 20th . The hydraulic system is also used 1 to an in 2 not, but in 1 illustrated parking lock 29 of the motor vehicle.

With 1 is the detailed structure of the hydraulic system according to the invention 1 easy to see according to a preferred embodiment. The hydraulic system 1 has a pump that has been redeployed as a reversing pump 2 on. The pump 2 is by means of an electric drive motor 18th depending on one by a power electronics 19th predetermined control command can be driven in a first conveying direction or a second conveying direction opposite thereto. The pump 2 consequently has two connections 3rd , 7th which alternately serve as inlet / suction connection or outlet / pressure connection. The pump 2 forms together with the drive motor 18th an electric pump actuator (EPA).

About the first connection 3rd is in the first delivery direction of the pump 2 a cooling and lubricating device 4th can be supplied with hydraulic fluid. As a drive for the pump 2 In the first conveying direction, hydraulic medium is supplied via the second connection 7th from a reservoir 17th sucked in and through the first connection 3rd , optionally with the interposition of a heat exchanger 26th , the cooling and lubricating device 4th fed.

The second connection 7th is via another line arrangement 5 with a parking lock actuator 8th and a clutch actuation device 9 connectable. In the second delivery direction of the pump 2 will be through the first connection 3rd from the reservoir 17th Hydraulic medium sucked in and towards the second port 7th towards a first valve 6th promoted. The first valve 6th is implemented as a directional valve. In particular, the first valve is 6th implemented as a 5/3-way valve. The second connection 7th is about the first valve 6th optionally with one to the parking lock actuation device 8th leading first line section 12th or one to the clutch actuator 9 leading second line section 13th or with a charging cable 14th connectable.

According to the invention, in this embodiment there is also a pressure accumulator 10 via another second valve 11 to the first line section 12th or the second line section 13th connectable or through the charging line 14th rechargeable.

The second valve 11 is also implemented as a directional valve, namely as a 4/3-way valve. In an in 1 converted first valve position of the second valve 11 is the pressure accumulator 10 with the first line section 12th and thus with the parking lock actuator 8th hydraulically connected while he is from the loading line 14th and the second line section 13th is separated. In a second valve position of the second valve 11 is the pressure accumulator 10 with the charging line 14th connected while being by the two first and second line sections 12th , 13th is separated. In a third valve position of the second valve 11 is the pressure accumulator 10 with the second line section 13th connected while he is from the first line section 12th and the charging line 14th is separated. Thus is the pressure accumulator 10 optionally with one of the actuating devices 8th , 9 , can be connected separately from each other or through the charging cable 14th as well as via the first valve 6th with the second connection 7th can be coupled for recharging.

The first valve 6th is in 1 shown in its first valve position, in which the second connection 7th with the second line section 13th is connected, while the first line section 12th from the second port 7th is separated. The first line section is in this first valve position 12th even via a return line 27 with the reservoir 17th connected. The charging line 14th is in this first valve position both from the return line 27 as well as from the second connection 7th severed.

In a second valve position of the first valve 6th is the first line section 12th with the second connection 7th connected, while the second line section 13th from this second port 7th is separated. Also the charging line 14th is in this second valve position of the second connection 7th as well as from the return line 27 severed. Also the second line section 13th is in this second valve position from the return line 27 severed.

In a third valve position of the first valve 6th Finally, there is the charging line 14th in connection with the second connection 7th , while the first and second line sections 12th , 13th from the second port 7th as well as from the return line 27 are separated.

It can also be seen that in the second line section 13th a check valve 28 is used, which is a return flow of hydraulic medium from the clutch actuator 9 towards the first valve 6th locks. To one of the first valve 6th remote side of the check valve 28 is on the second line section 13th a drain valve 16 connected, optionally the second line section 13th towards the reservoir 17th opens or separates from it.

In principle, it should also be pointed out that further explanations also refer to a parking lock actuating device 8th or on the clutch actuator 9 can be dispensed with and the first valve 6th or the second valve 11 can be implemented in a simplified manner in another way, always via the second valve 11 a pressure accumulator 10 to the one with the parking lock actuator 8th or the clutch actuator 9 connected pipe section 12th , 13th is connectable.

In other words, according to the invention, there is a reserve container 10 to control the parking lock 29 and the disconnect clutch K0 24 installed. This system design according to the invention reduces the switching frequency of EPA 2, since the hydraulic pressure required to control the parking lock 29 and the separating clutch K0 24 from the reserve tank 10 can be taken. If the holding magnet fails 15th the parking lock 29 can take the pressure and volume from the reserve tank 10 via a separate valve 11 in the Direction of the parking lock 29 and engaging the parking lock 29 prevent while driving. This also means that the parking lock needs to be changed 29 prevented or only has to be carried out at the next service appointment. In addition, the disconnect clutch can be closed in an emergency 24 without interrupting the cooling. The latency time is reduced compared to the previous system because of the EPA 2 does not have to reverse its direction of rotation. If the directional control valve fails 6th can parking lock 29 and disconnect clutch 24 via the reserve tank 10 continue to be operated. In general, the changes in the direction of rotation of EPA 2 are also reduced, since the parking lock is activated 29 and disconnect clutch 24 primarily from the reserve tank 10 he follows. This also reduces cooling interruptions.

List of reference symbols

1

Hydraulic system

2

pump

3

first connection

4th

Cooling and / or lubricating device

5

Line arrangement

6th

first valve

7th

second connection

8th

Parking lock actuator

9

Clutch actuation device

10

Pressure accumulator

11

second valve

12th

first line section

13th

second line section

14th

Charging line

15th

Holding magnet

16

Drain valve

17th

reservoir

18th

Drive motor

19th

Line electronics

20th

Drive unit

21st

Internal combustion engine

22nd

first electric motor

23

second electric motor

24

Disconnect clutch

25th

wheel

26th

Heat exchanger

27

Return line

28

check valve

29

Parking lock

QUOTES INCLUDED IN THE DESCRIPTION

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

Patent literature cited

• DE 102018112670 [0002]
• DE 102019100872 [0002]

Claims (9)

Hydraulic system (1) for a motor vehicle, with a pump (2) reversible in its conveying direction, a cooling and / or lubricating device (4) coupled to a first connection (3) of the pump (2), one via a line arrangement (5) as well as a first valve (6) with a second connection (7) of the pump (2) and a parking lock actuation device (8) which can be coupled via the line arrangement (5) and the first valve (6) likewise to the second connection (7) of the pump ( 2) couplable clutch actuation device (9), characterized in that a pressure accumulator (10) is connected to a first line section (12) of the line arrangement (5) running between the first valve (6) and the parking lock actuation device (8) by means of a second valve (11) and / or can be coupled to a second line section (13) of the line arrangement (5) running between the first valve (6) and the clutch actuation device (9). Hydraulic system (1) Claim 1 , characterized in that a charging line (14), which connects the second connection (7) of the pump (2) to the pressure accumulator (10) in at least one operating state, runs between the first valve (6) and the second valve (11) . Hydraulic system (1) Claim 1 or 2 , characterized in that the first valve (6) is designed such that in its first valve position it connects the second connection (7) of the pump (2) to the second line section (13), while the first line section (12) of the second connection (7) of the pump (2) is separated, in its second valve position the second connection (7) of the pump (2) connects to the first line section (12), while the second line section (13) connects to the second connection (7 ) the pump (2) is separated, and / or in its third valve position connects the second connection (7) of the pump (2) to the charging line, while the first line section (12) and the second line section (13) from the second connection (7) of the pump (2) are disconnected. Hydraulic system (1) according to one of the Claims 1 to 3rd , characterized in that the second valve (11) is designed such that it connects the pressure accumulator (10) to the first line section (12) in its first valve position, while the second line section (13) and the charging line (14) of the Pressure accumulator (10) are separated, in its second valve position the pressure accumulator (10) connects to the charging line (14), while the first line section (12) and the second line section (13) are separated from the pressure accumulator (10), as well as in its third valve position connects the pressure accumulator (10) to the second line section (13), while the first line section (12) and the charging line (14) are separated from the pressure accumulator (10). Hydraulic system (1) according to one of the Claims 1 to 4th , characterized in that the parking lock actuation device (8) has a holding magnet (15) which can be controlled such that it holds the parking lock actuation device (8) in an open position when the motor vehicle is in operation. Actuator system (1) according to one of the Claims 1 to 5 , characterized in that the second line section (13) is connected to a drain valve (16), via which drain valve (16) it can be connected to a reservoir (17). Hydraulic system (1) according to one of the Claims 1 to 6th , characterized in that the pump (2) is used in such a way that when it is driven in a first conveying direction, hydraulic medium is conveyed via the first connection (3) to the cooling and / or lubricating device (4) and when it is driven in a second Conveying direction hydraulic medium is conveyed via the second connection (7) to the first valve (6). Hydraulic system (1) according to one of the Claims 1 to 7th , characterized in that the first valve (6) and / or the second valve (11) are / is designed as a directional valve. Drive unit (20) for a motor vehicle, with a hydraulic system (1) according to one of the Claims 1 to 8th .

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