DE102006060645B4 - Motor-pump unit - Google Patents

Abstract

Motor-pump unit (1), which is provided as a vacuum pump for providing pressure for a vacuum booster of a motor vehicle brake system, comprising a pump (2) designed as a pneumatic diaphragm pump and an electric motor (3) driving the pump (2), the The pump has at least one working chamber (7) to which an inlet channel (11) with an inlet valve (12) and an outlet channel (13) with an outlet valve (14) are assigned, the pump having a silencer (15), characterized in that at least one outlet channel (13) is provided in a work space cover (6) and a pump housing (5) in the pump (2) for soundproofing in such a way that air displaced from the work space (7) into an interior space (28) of the pump housing (5), the pump (2) having an air outlet unit (29) and a third valve (16) as part of the air outlet unit (29) in the area of the interior (28) has through which the air exits from the interior (28) into the atmosphere.

Description

The invention relates to a motor-pump unit comprising a pump and an electric motor driving the pump, the pump having at least one working chamber, to which (working chamber) an inlet channel with an inlet valve and an outlet channel with an outlet valve are assigned, the pump having a silencer.

the end U.S. 4,743,169 A a single-piston diaphragm vacuum pump with a spring-controlled valve for maintaining a predetermined negative pressure level in the consumer is known. When a certain negative pressure is reached in the consumer, the valve opens and lets air from the atmosphere into a working chamber, whereby the pump switches to quasi-idling, but has no additional soundproofing measures.

From the DE 42 39 575 A1 For example, a generic motor-pump unit is known. This has known soundproofing measures such as a soundproofing element made of plastic.

In order to achieve good noise absorption, known motor-pump assemblies have a silencer with a silencer element which, however, severely impedes the flow of the conveyed medium. Therefore, with low noise emissions, these have the disadvantage that, for example, the pressure in the pump increases too much and the efficiency of the pump decreases as a result. Furthermore, the soundproofing measures often lead to heat build-up in the pump, which significantly shortens the service life of the pump.

It is therefore the object of the present invention to provide an improved motor-pump unit which, with undiminished pump performance and a long service life, takes into account the requirements with regard to acoustic comfort.

According to the invention, this object is achieved by a pump unit with a combination of features according to independent claim 1.

A third valve for sound dampening can be designed in such a way that it opens when there is a small pressure difference. At the same time, it can dampen the noises when the medium enters or exits without any negative effect on the passage of the medium. This prevents heat from building up in the pump.

For this purpose, the pump is preferably designed as a pneumatic double diaphragm pump with two opposing diaphragms, which are each clamped between a pump housing and a work space cover and thereby delimit the work space and which can be moved by means of a drive.

According to the invention, the outlet channels are provided in the working chamber covers and in the pump housing in such a way that air displaced from the working chambers is guided into an interior of the pump housing, the pump having an air outlet unit in the area of the interior. The third valve is provided as part of the air outlet unit, which does not increase the installation space required.

Too high a pressure in the interior of the pump can be prevented by simple means in that the third valve is provided as a check valve. Furthermore, the check valve allows reliable protection against penetration of liquid or gaseous substances into the interior of the pump.

The third valve is preferably provided as a plate swing valve and comprises a valve housing, a valve disc as a valve body and a cover element. In order to provide a preassembled unit, the cover element can be connected to the valve housing. For this purpose, the cover element can preferably be welded, screwed or riveted to the valve housing.

In order to reduce the number of components in the motor / pump assembly, it is provided according to an advantageous embodiment that the valve housing forms part of the pump housing and sealingly closes an opening in a pump housing wall.

Alternatively, according to another advantageous embodiment, the valve housing can be connected to a pump housing cover, which enables the individual components to be manufactured more easily.

The valve housing can preferably be riveted, welded or screwed to a pump housing cover.

Further noise reduction can be achieved in that the air outlet unit comprises a filter. It is advantageous if the filter is arranged in the valve housing of the third valve and covers the cover element. An additional fastening of the filter can thus be omitted and the positioning of the filter is made easier.

Further features, advantages and possible applications of the invention emerge from the following description of two exemplary embodiments and with reference to the drawing.

• 1 einen Ausschnitt eines ersten Ausführungsbeispiels eines erfindungsgemäßes Motor-Pumpenaggregat im Längsschnitt, stark schematisiert;
• 2 ein zweites Ausführungsbeispiel eines erfindungsgemäßes Motor-Pumpenaggregat in räumlicher Darstellung;
• 3 das Motor-Pumpenaggregat gemäß 4 im Längsschnitt durch eine erste Ebene und
• 4 einen Arbeitraumdeckel des Motor-Pumpenaggregates gemäß 4 im Längsschnitt durch eine zweite Ebene.

It shows:

• 1 a section of a first embodiment of a motor-pump assembly according to the invention in longitudinal section, highly schematized;
• 2 a second embodiment of a motor-pump assembly according to the invention in a three-dimensional representation;
• 3 the motor-pump unit according to 4th in a longitudinal section through a first level and
• 4th a working space cover of the motor-pump unit according to 4th in a longitudinal section through a second level.

1 shows a section of a first embodiment of a motor-pump assembly according to the invention 1 highly schematic in longitudinal section. The motor-pump unit 1 is used in particular to provide negative pressure for a brake actuation device of a motor vehicle brake system with a vacuum brake booster and, as in the second exemplary embodiment described below, can have a vacuum pump as the pump.

The motor-pump unit 1 includes a pump 2 and one the pump 2 driving electric motor, not shown, the pump 2 has at least one working chamber, each of which is assigned an inlet channel with an inlet valve and an outlet channel with an outlet valve. Because the automotive industry in particular has very high requirements with regard to the acoustic comfort of the pump 2 are placed, this has a silencer 15th on. The silencer 15th is controlled by a third valve 16 the pump 2 and is provided as a check valve.

As can be seen, the valve is 16 specifically intended as a plate vibrator valve and comprises a valve housing 30th , a valve disc 34 as a valve body and a cover element 33 , which by means of a fastening element 37 on the valve housing 30th is attached. The fastener 37 can for example be provided as a screw element. It is also conceivable that the two components (valve housing 30th and cover element 33 ) to be connected by means of a rivet. A connection by means of welding is also possible.

• Ein Arbeitsraum der Pumpe 2, dessen Volumen in einer bestimmten Phase der Betätigung sehr gering ist, d.h. vorzugsweise gegen Null geht, wird bei Drehung eines Antriebs vergrößert, wodurch der Druck im Arbeitsraum so stark abnimmt, dass ein Teil der in einer Vakuumkammer des Bremskraftverstärkers befindlichen Restluft über einen nicht gezeigten Anschluss der Pumpe 2 und den Einlasskanal in den Arbeitsraum angesaugt wird. Durch den Ansaugvorgang öffnet sich das Einlassventil. Verkleinert sich der Arbeitsraum durch die weitere Drehung des Antriebs, schließt das Einlassventil und das Auslassventil öffnet. Dabei wird die angesaugte Restluft aus dem Arbeitsraum über einen Kanal und den Auslasskanal heraus geblasen. Die aus dem Arbeitsraum verdrängte Luft wird in einen Innenraum 28 der Pumpe 2 geleitet, welcher so als Schalldämpfungsraum dient.

The following describes the provision of negative pressure in the motor-pump unit 1 described:

• A working space of the pump 2 , the volume of which is very small in a certain phase of actuation, ie preferably approaches zero, is increased when a drive rotates, whereby the pressure in the working space decreases so much that part of the remaining air in a vacuum chamber of the brake booster passes through a not shown Connection of the pump 2 and the inlet channel is sucked into the working space. The intake valve opens as a result of the suction process. If the working space is reduced by the further rotation of the drive, the inlet valve closes and the outlet valve opens. The remaining air sucked in is blown out of the working space through a duct and the outlet duct. The air displaced from the work space is released into an interior 28 the pump 2 guided, which serves as a soundproofing room.

When the air pressure in the interior 28 the pump 2 becomes larger than that of the pump 2 ambient atmospheric pressure, the valve opens 16 by moving the valve body 34 of through holes 38 in the valve body 30th at least partially lifts off and the air through openings 19th in the cover element 33 can escape into the atmosphere. Thus, on the one hand, the pressure in the interior 28 the pump 2 just about the small one, to open the valve 16 necessary differential pressure value increase above atmospheric pressure and on the other hand the pressure in the interior 28 subject to periodic fluctuations in the cycle of the interior volume change associated with the crank movement. This results in a time-averaged interior pressure below atmospheric pressure.

The valve 16 allows air to be blown out of the interior with little noise 28 , because the airborne sound when the air exits the interior 28 on the valve body 34 is broken. At the same time, the valve prevents 16 the penetration of liquid or gaseous substances into the interior 28 . Even with an open valve 16 the ingress of dirt is not to be expected due to the escaping air flow L.

Furthermore, the low throttling of the blown air removes the heat from the pump 2 reduced only very slightly and a pump cooling by the air flow L is maintained. This cooling extends the life of the pump 2 , because there is a build-up of heat in the pump 2 an early failure of the motor used to drive the pump, which is preferably designed as an electric motor, would lead. Is the pump 2 Designed as a diaphragm pump, the described heat build-up also leads to premature aging and thus to premature failure of the diaphragm.

the 2 until 4th show a second embodiment of a motor / pump assembly according to the invention in a three-dimensional representation and in a longitudinal section.

2 shows the second embodiment of the motor-pump assembly according to the invention 1 in three-dimensional representation, which is a pump 2 with a pump housing 5 and one the pump 2 driving electric motor 3 includes, the engine 3 can for example be designed as a DC motor.

The pump 2 is how particular out 3 shows which is the motor-pump unit 1 shows in a longitudinal section through a first plane, as a double diaphragm pump with two opposing diaphragms 4th provided, each between the pump housing 5 and a work space cover 6th is clamped and thus a work area 7th limited. The membrane 4th are by means of a crank drive 8th movable in opposite directions, whichever membrane 4th an eccentric 9 and a connecting rod 10 includes.

In 4th is the workspace cover 6th of the motor-pump unit 1 shown in section. It can be seen that the work space cover 6th an upper lid 55 as well as a lower cover 56 which, depending on the material - plastic or aluminum - are welded or screwed together airtight. The centering of the top cover 55 on the lower cover 56 takes place, for example, by one on the top cover 55 molded welding allowance 65 , which during the assembly of the top cover 55 in a corresponding contour 66 reaching into it.

On the pump housing 5 is an in 2 Connection shown 25th with an adapter sealingly attached in it 57 provided, via which the connected brake booster is evacuated. The adapter 57 can, for example, be angled as shown. However, according to customer requirements, a straight adapter is also available 57 possible. Next is the design of an adapter outlet 58 , to which a vacuum hose (not shown) is attached, configured differently depending on the type of connection. In addition to the Christmas tree profile shown, a quick-release or snap-in lock is also conceivable.

The adapter 57 can either be inserted into the connector by means of a snap-in connection 25th be positioned or the connection adapter connection is provided rotatably. The rotatable configuration of the connection can, for example, by means of pin-shaped elements 59 which in holes of the connection 25th protrude and into an invisible outer groove of the adapter 57 intervene, be realized.

The connection 25th opens into a housing bore, not shown, which branches into two channels formed in the pump housing which lead to the two working chamber covers 6th to lead. This makes it possible to cover the work area 6th for both sides of the pump 2 design the same, whereby the assembly is significantly simplified. Advantageously, a second connection 25th on the opposite side of the pump housing 5 be provided. This makes it possible, depending on customer requirements and the installation conditions of the motor-pump unit 1 the adapter 57 to be connected either on one side or on the opposite side. One of the connections 25th be tightly closed by means of a stopper. It is also conceivable to use one of the connections 25th to leave closed during manufacture and only to be opened when necessary, for example by drilling.

In each of the workspace covers 6th is one in the top lid 55 trained inlet channel 11 provided, which is connected airtight to the mentioned pump housing channel by means of a sealing element and the sucked air to an inlet valve 12th forwards. The inlet valve 12th is preferably a plate valve with a valve disc 17th made of elastic material. The one from the elastomeric valve disc 17th The total passage area to be covered is expediently divided into several small passage areas, each with a circular cross-section. The inlet channel branches for this purpose 11 in the top lid 55 into a corresponding number of individual channels 60 , which is circular around a central axis of the inlet valve 12th are arranged.

After flowing through the inlet valve 12th the sucked in air reaches the workspace cover openings 61 in the lower lid 56 in the work room 7th between membrane 4th and work space cover 6th , is compressed there and through further workspace cover openings 62 to the exhaust valve 14th out, which is also a plate valve with a valve disc 18th is formed from elastomeric material. As can be seen, there is an exhaust port 13th between top cover 55 and lower cover 56 educated.

Around the work space 7th with a very small residual volume, the workspace cover 6th In this exemplary embodiment, too, a three-dimensional shape that adapts to the envelope of a membrane surface on the working space side 52 is adapted, which by the tilting movement of a crank drive 8th moving ram 45 is induced. The three-dimensional inner contour of the working space cover is preferably adapted to the envelope by maintaining a predetermined small distance between the areas of a section that is difficult to deform 50 the membrane 4th and the work space cover 6th , while the distance in the areas of an easily deformable section 44 the membrane 4th and a membrane bead 51 is chosen to be zero. The small distance between the inner contour of the workspace cover and the envelope of the membrane surface on the workspace side 52 in the central area of the membrane 4th prevents it from hitting the work area cover 6th when operating the pump 2 and allows even in the top dead center of the crank drive 8th an air flow between the work space 7th and the workspace ceiling openings 61 , 62 .

The workspace cover openings 61 , 62 are part of the so-called harmful volume, ie the residual volume remaining when ejected. The remaining air under atmospheric pressure expands during the suction process, which means that less volume can be sucked in. It is therefore useful to open the work space cover 61 , 62 design with the smallest possible volume.

Inlet and outlet valve 12th , 14th are therefore tangential to the inner contour of the workspace cover, ie at an angle to the planes of symmetry of the pump 2 , arranged and the workspace cover openings 61 , 62 are designed as short holes. This design of the work space cover 6th takes up little space as a further advantage.

From the exhaust valve 14th is the expelled air through the exhaust duct 13th in the work area cover 6th to an outlet channel (not shown) in the pump housing 5 directed. The exhaust ducts 13th in the workspace cover 6th and pump housing 5 are connected airtight by means of a sealing element. The two outlet channels in the pump housing 5 flow into the interior 28 of the pump housing 5 , the so-called crank chamber.

For easier assembly of the valve discs 17th , 18th shows the lower cover 56 in the area of the valves 12th , 14th one positioning pin each 63 , 64 on which of the guide of the valve disks 17th , 18th serves.

The inlet valve 12th further has two on the top cover 55 provided coaxial circular sealing surfaces 67 , 68 on, which are designed as circumferential projections, with a sealing surface 67 outside of the individual channels 60 and a sealing surface 68 within the individual channels 60 is arranged. By reducing the sealing surface, a greater sealing effect is achieved and the valve disc sticks 17th on the top cover 55 , especially at low temperatures, is excluded.

One in the pump housing 5 provided air outlet unit 29 allows air to be blown out of the interior with little noise 28 . The interior 28 thus serves as a soundproofing room. The air outlet unit 29 comprises the third valve described for the first embodiment 16 , which is a plate rocker valve with the valve disc 34 is provided and that a backflow of already expelled air and the penetration of liquid or gaseous substances into the interior 28 prevented. The valve takes up additional space 16 through integration in the air outlet unit 29 not used.

The airborne sound becomes even wider when the air exits the interior 28 reduced by the fact that the air outlet unit 29 one, in the valve housing 30th arranged filter 31 having the cover element 33 of the valve 16 covered and through which the air escapes into the atmosphere. An additional attachment of the filter 31 can by the arrangement in the valve housing 30th dispensed with and a positioning of the filter 31 is simplified.

The air outlet unit further comprises 29 a pump housing cover 32 with which the valve housing 30th can be riveted or also welded or screwed, as shown, so that the air outlet unit 29 represents a preassembled assembly. It is also conceivable that the valve housing 30th and the pump housing cover 32 to be provided in one piece.

• Wenn der Luftdruck im Innenraum 28 der Pumpe größer wird, als der die Pumpe umgebende Atmosphärendruck, öffnet sich das Ventil 16, indem sich der Ventilkörper 34 von den Durchgangsbohrungen 38 im Ventilgehäuse 30 zumindest teilweise abhebt, und die Luft durch in 1 dargestellte Öffnungen 19 des Deckelelementes 33 und durch den Filter 31 aus dem Pumpengehäuse 5 in die Atmosphäre entweichen kann. Somit kann einerseits der Druck im Innenraum 28 der Pumpe 2 nur um den geringen, zum Öffnen des Ventils 16 notwendigen Differenzdruckwert über den Atmosphärendruck anwachsen und andererseits ist der Druck im Innenraum 28 periodischen Schwankungen im Takt der mit der Kurbelbewegung einhergehenden Innenraumvolumenänderung unterworfen. Dadurch ergibt sich ein zeitlich gemittelter Innenraumdruck unterhalb des Atmosphärendrucks.

The function of the valve 16 corresponds to the function as already described for the first exemplary embodiment:

• When the air pressure in the interior 28 the pump becomes greater than the atmospheric pressure surrounding the pump, the valve opens 16 by moving the valve body 34 from the through holes 38 in the valve body 30th at least partially lifts off, and the air through in 1 openings shown 19th of the cover element 33 and through the filter 31 from the pump housing 5 can escape into the atmosphere. Thus, on the one hand, the pressure in the interior 28 the pump 2 just about the small one, to open the valve 16 necessary differential pressure value increase above atmospheric pressure and on the other hand the pressure in the interior 28 subject to periodic fluctuations in the cycle of the interior volume change associated with the crank movement. This results in a time-averaged interior pressure below atmospheric pressure.

The valve 16 in this exemplary embodiment also enables the air to be blown out of the interior space with little noise 28 , because the airborne sound when the air exits the interior 28 on the valve body 34 is broken. At the same time, the valve prevents 16 the penetration of liquid or gaseous substances into the interior 28 . Self when the valve is open 16 the ingress of dirt is not to be expected due to the escaping air flow L.

Furthermore, the low throttling of the blown air removes the heat from the pump 2 reduced only very slightly and a pump cooling by the air flow L is maintained. This cooling extends the life of the pump 2 , because there is a build-up of heat in the pump 2 an early failure of the motor used to drive the pump, which is preferably designed as an electric motor, would lead. Is the pump 2 Designed as a diaphragm pump, the heat build-up described also leads to premature aging and thus to premature failure of the diaphragm.

the end 3 it can also be seen that a motor shaft 39 of the electric motor 3 in a first, not shown, in the engine 3 arranged warehouse and in a second warehouse 40 is stored, the second bearing 40 partly from a motor housing 41 and partly from the pump housing 5 is recorded. This results in an advantageous centering of the engine 3 and pump 2 achieved. The attachment of the engine 3 on the pump housing 5 takes place by means of screw elements, not shown, which are in the pump housing 5 inserted threaded inserts engage when the pump housing 5 is made of plastic.

The motor shaft 39 serves at the same time as an eccentric shaft in this embodiment 43 , which the crank drive 8th with the eccentrics 9 and the connecting rods 10 wearing. However, it is also a separate version of the motor shaft 39 and eccentric shaft 43 according to the first embodiment described possible.

To ensure that the motor-pump unit runs smoothly 1 to ensure, are the centers of the eccentrics 9 based on a central axis of the motor shaft 39 arranged diametrically and equidistantly, ie the eccentrics 9 are offset by 180 °. This can reduce the reaction forces of the oscillating masses of membranes 4th , Connecting rods 10 and eccentrics 9 are almost balanced, since in every phase of their movement the common center of gravity remains at least approximately at rest. The remaining small deviation from an ideal mass balance is due to the fact that the two eccentrics 9 , as in 3 shown, are arranged axially offset, while the membranes 4th move at the same axial height.

3 it can also be seen that the membrane 4th the work space 7th from the interior 28 separates and tightly with the plunger 45 is connected, the preferably non-deformable plunger 45 of the elastically deformable material of the membrane 4th can be overmolded. This arises in the vicinity of the ram 45 the already mentioned, difficult to deform section 50 in the center of the membrane 4th that is outward in the easily deformable section 44 the membrane 4th merges, this in turn outwardly into a membrane bead 51 passes over to the pump housing 5 is firmly and airtightly connected. The plunger 45 can either be welded or threaded to the connecting rod 10 be connected. However, it can also be used with the connecting rod 10 be provided in one piece. The connecting rods 10 are by means of ball bearings 46 on the eccentrics 9 movably mounted.

Are the connecting rods 10 made of plastic, injected support rings can be used 69 the seat of the ball bearings in the area of a connecting rod eye 46 in the connecting rods 10 stabilize. Alternatively, in the connecting rods 10 Slits formed in the area of the connecting rod eye the ball bearings 46 enclose resiliently.

A weight-optimized motor-pump unit 1 is obtained by the fact that the pump housing 5 and the work space cover 6th are made of plastic, for example by means of injection molding, with individual parts produced by injection molding are preferably connected to one another by ultrasonic welding. Furthermore, the pump housing 5 and the work space cover 6th or only the pump housing 5 be made of aluminum, since aluminum dissipates heat well from the engine 3 permitted. A material combination of plastic and aluminum is conceivable for the two parts.

The inlet and outlet channels are advantageous 11 , 13th in the pump housing 5 positioned so that the two work space covers 6th can be designed identically.

The work space covers 6th as well as the pump housing 5 Means for the defined positioning of the work space cover 6th on the pump housing 5 to make assembly easier and to avoid incorrect positioning.

Flow channels that form the connecting surface between the workspace cover 6th and pump housing 5 penetrate, are in the transitions between the work space cover 6th and pump housing 5 Gas-tight to their surroundings - for example through the use of sealing elements by means of gas-tight welding.

The air outlet unit described above 29 is designed as a preassembled unit and for installation in a breakthrough 48 one to the engine 3 facing away wall 53 of the pump housing 5 intended. The pump housing cover is used for this 32 with the wall 53 by means of screw elements 35 tied together. The breakthrough is fulfilled 48 before inserting the air outlet unit 29 the function of a mounting window that provides access to the interior 28 of the pump housing 5 allowed.

The exhaust ducts 13th flow into the interior 28 of the pump housing 5 so that this acts as an acoustic damping chamber to reduce the exit sound when air is expelled from the work rooms 7th serves.

The above-described motor-pump units according to the invention 1 are not limited to the described application of providing vacuum. Such motor-pump units 1 can be used wherever gases with high efficiency and low noise emissions are to be brought from a first pressure level to a higher second pressure level. For example, there is also an application of the motor / pump assembly according to the invention 1 conceivable as a compressor, with the installation direction of the valves preferably being reversed in this application so that the air is sucked in from the interior 28 of the pump housing 5 and delivering compressed air through the port 25th he follows.

List of reference symbols

1

Motor-pump unit

2

pump

3

engine

4th

membrane

5

Pump housing

6th

Work area cover

7th

working space

8th

drive

9

eccentric

10

connecting rod

11

Inlet port

12th

Inlet valve

13th

Exhaust duct

14th

outlet valve

15th

silencer

16

Valve

17th

Valve disc

18th

Valve disc

19th

openings

25th

connection

28

inner space

29

Air outlet unit

30th

Valve body

31

filter

32

Pump housing cover

33

Cover element

34

Valve body

35

Screw element

37

Screw element

38

Through hole

39

Motor shaft

40

camp

41

Motor housing

43

Eccentric shaft

44

section

45

Plunger

46

ball-bearing

48

breakthrough

50

section

51

Membrane bead

52

Membrane surface

53

Wall

55

Top cover

56

Lower cover

57

adapter

58

Adapter outlet

59

element

60

Single channel

61

Workspace cover opening

62

Workspace cover opening

63

Positioning pin

64

Positioning pin

65

Welding allowance

66

contour

67

Sealing surface

68

Sealing surface

69

Support ring

Claims (16)

Motor-pump unit (1), which acts as a vacuum pump to provide pressure for a vacuum booster of a motor vehicle brake system is provided, comprising a pump (2) designed as a pneumatic diaphragm pump and an electric motor (3) driving the pump (2), the pump having at least one working chamber (7), which (working chamber (7) in each case an inlet channel (11) with inlet valve (12) and an outlet channel (13) with outlet valve (14) are assigned, the pump having a silencer (15), characterized in that at least one outlet channel (2) in the pump (2) for silencing 13) is arranged in a work space cover (6) and a pump housing (5) in such a way that air displaced from the work space (7) is guided into an interior (28) of the pump housing (5), the pump (2) in the area of the interior (28) has an air outlet unit (29) and a third valve (16) as part of the air outlet unit (29) through which the air exits from the interior (28) into the atmosphere. Motor-pump unit (1) Claim 1 , characterized in that the pump (2) is designed as a pneumatic double diaphragm pump with two opposing diaphragms (4) which is each clamped between a pump housing (5) and a work space cover (6) and thereby delimits the work space (7) and which by means of a drive (8) are movable. Motor-pump unit (1) Claim 1 or 2 , characterized in that the third valve (16) is provided as a check valve. Motor-pump unit (1) Claim 3 , characterized in that the third valve (16) is provided as a plate swing valve and comprises a valve housing (30), a valve disc as a valve body (34) and a cover element (33). Motor-pump unit (1) Claim 4 , characterized in that the cover element (33) is connected to the valve housing (30). Motor-pump unit (1) Claim 5 , characterized in that the cover element (33) is welded to the valve housing (30). Motor-pump unit (1) Claim 5 , characterized in that the cover element (33) is screwed to the valve housing (30). Motor-pump unit (1) Claim 5 , characterized in that the cover element (33) is riveted to the valve housing (30). Motor-pump unit (1) after one of the Claims 5 until 8th , characterized in that the valve housing (30) forms part of the pump housing (5) and seals an opening (48) in a pump housing wall (53). Motor-pump unit (1) after one of the Claims 5 until 8th , characterized in that the valve housing (30) is connected to a pump housing cover (32). Motor-pump unit (1) Claim 10 , characterized in that the valve housing (30) is riveted to a pump housing cover (32). Motor-pump unit (1) Claim 10 , characterized in that the valve housing (30) is welded to a pump housing cover (32). Motor-pump unit (1) Claim 10 , characterized in that the valve housing (30) is screwed to a pump housing cover (32). Motor-pump unit (1) according to one of the preceding Claims 1 until 13th , characterized in that the air outlet unit (29) comprises a filter (31). Motor-pump unit (1) Claim 14 , characterized in that the filter (31) is arranged in the valve housing (30) of the third valve (16) and covers the cover element (33). Motor vehicle brake system, characterized in that the motor vehicle brake system comprises a motor-pump unit (1) according to one of the preceding claims.

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