DE102011006525A1 - Electric motor-pump assembly has recess formed in lower cover in which valve disc of intake valve is engaged during suction of air via inlet channel, where intake and sealing surfaces of valve are matched with shape and size of recess - Google Patents

Abstract

The motor-pump assembly (1) has a pump (2) with a pump housing (5) on which a working chamber cover (6) is attached to limit a working chamber of the pump. The chamber cover is formed with lower and upper covers which are sealably connected. The exhaust valve and intake valve are provided between the lower and upper covers. A recess is formed in lower cover in which a valve disc of the intake valve is engaged during suction of air via an inlet channel. The intake and sealing surfaces of the intake valve are matched with shape and size of the recess.

Description

The invention relates to a motor-pump unit for providing negative pressure comprising a pump and an electric motor driving the pump, wherein the pump has a pump housing and at least one displacement element which defines a working space with a work space lid attached to the pump housing, wherein the working space an inlet channel associated with inlet valve and an outlet channel with outlet valve, wherein the working space cover has an upper lid and a lower lid, which are sealed together, wherein the valves between upper lid and lower lid are provided and each having a valve disc.

A generic motor-pump unit is for example from the DE 10 2009 054 499 A1 known. In each of the working space lid an inlet channel formed in the upper cover is provided, which forwards the sucked air to an inlet valve. The inlet valve is designed as a plate valve with a valve disc of elastic material and arranged in a corresponding recess of the upper lid. Between upper and lower cover a holding element is provided, which holds the valve disc on the upper lid and at the same time allows a valve movement. However, this valve technology is not dead space-optimized.

There are always efforts to improve the characteristics of the motor-pump unit such as the manufacturing cost, the life, the acoustic comfort and so on. Furthermore, a high final vacuum and / or short suction times are desired.

It is therefore an object of the present invention to provide a motor-pump unit improved to that effect.

The object is achieved according to the invention in that the lower cover has a recess into which the valve disc of the inlet valve can dive with a valve tongue during intake of the air via the inlet channel, wherein an inlet surface and a sealing surface of the inlet valve and a shape and a size of the recess the lower lid are provided so coordinated with each other that the recess of the inlet valve is optimally utilized. The well-known in the art, not dead space-optimized valve technology including the recess in the upper cover omitted, whereby the dead space can be reduced or optimized. A smaller dead space causes primarily a higher achievable final vacuum and secondarily faster Absaugzeiten, thereby advantageously results in a reduction of the necessary running time of the pump.

Preferably, the recess is provided in a wedge-shaped manner in the longitudinal section and merges into the working space. There are no further recesses or channels, which can increase the dead volume.

A compromise between the necessary valve sealing surface and utilization of the inlet surface of the inlet valve can be achieved according to an advantageous development that branches the inlet channel in the region of the recess in at least two individual channels.

According to a particularly advantageous embodiment, the inlet channel branches in the region of the recess in three triangular or semicircular arranged individual channels. It is here to achieve a particularly optimal compromise between the necessary valve sealing surface and utilization of the inlet surface of the inlet valve.

Preferably, the recess of the lower lid is formed substantially semicircular in cross-section and the valve tongue of the inlet valve is provided correspondingly semicircular. Optimal is the embodiment when the recess in the lower lid is designed to be just as large as the folding area of the valve disc, d. H. like the valve tongue. However, it is usually necessary for tolerance and assembly reasons, the immersion area of the valve tongue, d. H. slightly enlarge the recess of the lower cover to allow trouble-free operation of the intake valve.

In order to improve the air flow in the inlet channel, the inlet channel is preferably formed parallel to a central axis in the upper lid and opens into the region of the individual channels.

The assembly cost can be significantly reduced if a molded seal is provided for sealing the upper lid and the lower lid, which has a plurality of sealing element elements and the valve discs of inlet and / or outlet valve are integrally formed on the molded seal.

The pump may for example be provided as a double diaphragm pump with two opposite working membranes, which is clamped between a pump housing and a working space cover and thereby limits a working space and which are movable by means of a crank drive.

Advantageously, the motor-pump unit according to the invention for the provision of Vacuum be provided for a brake actuator of a motor vehicle brake system with a vacuum brake booster.

Other features, advantages and possible applications of the invention will become apparent from the following description of exemplary embodiments and with reference to the drawings.

It shows:

1 a known motor-pump unit in exploded view;

2 the motor-pump unit according to 1 in long section through a first level;

3 a work space cover of the motor-pump unit according to 1 in long section through a second level;

4 Individual parts of the work space cover according to 3 in spatial view;

5 a first embodiment of an inventive motor-pump unit partially cut in a spatial representation;

6 a section of the motor-pump unit of a second embodiment and

7 a plan view of a valve disc of an intake valve of the engine-pump assembly according to 6 ,

1 shows a known motor-pump unit 1 in an exploded view, which is a pump 2 with a pump housing 5 and one the pump 2 driving electric motor 3 includes, wherein the engine 3 for example, can be designed as a DC motor.

The pump 2 , as in particular from the sectional representation gemaß 2 is apparent as a double diaphragm pump with two opposing working diaphragms 4 provided, which in each case between the pump housing 5 and a work space cover 6 is clamped and thereby a working space 7 limited. The working membrane 4 are by means of a crank drive 8th movable in opposite directions, which ever working membrane 4 an eccentric 9 and a connecting rod 10 includes.

The in 3 in section shown work space cover 6 has an upper lid 11 and a lower lid 12 on, which are airtight welded together, riveted or screwed.

In each of the working space lids 6 is one in the upper lid 11 trained inlet channel 13 provided with channels in the pump housing 5 is connected airtight by means of a sealing element and the sucked air to an inlet valve 14 forwards. The inlet valve 14 is as a plate valve with a valve disc 15 made of elastic material. This is 4 to see what the individual parts of the work space cover 6 in a spatial view represents that of the elastomeric valve disk 15 To be covered total entry area thereby expediently divided into several small entry surfaces each having a circular cross-section. For this, the inlet channel branches 13 in the upper lid 11 into a corresponding number of individual channels 16 which is annular about a center axis of the intake valve 14 are arranged.

After passing through the inlet valve 14 the sucked air passes through working space lid openings 17 in the lower lid 12 in the workroom 7 between membrane 4 and workspace lid 6 , is compressed there and over further work space lid openings 18 to the exhaust valve 19 guided, which also as a plate valve with a valve disc 20 is formed of elastomeric material. As can be seen, is an outlet channel 21 between upper lid 11 and lower lid 12 educated.

From the outlet valve 19 The ejected air is via the outlet channel 21 in the workspace lid 6 to an outlet channel, not shown, in the pump housing 5 directed. The outlet channels 21 in the work space lids 6 and in the pump housing 5 are connected airtight by means of a sealing element. The two outlet channels in the pump housing 5 lead into an interior 22 of the pump housing 5 , the so-called crank space, which the crank drive 8th surrounds.

One in the pump housing 5 provided air outlet unit 23 allows a low-noise blowing out of the air from the interior 22 , which thus serves as Schalldampfungsraum.

Between the upper lid 11 and the lower lid 12 is for sealing a molded seal 24 provided the multiple sealing elements 25 . 26 . 27 for sealing the different areas between the two components 11 . 12 and in a corresponding recess 28 of the upper lid 11 can be inserted. By the connection of the individual sealing elements 25 - 27 to the mold seal 24 The assembly can be significantly simplified and the production costs can be reduced. Furthermore, the number of individual components is reduced.

A holding element 29 in the area of the inlet valve 14 holds the valve disc 15 on the upper lid 11 and at the same time ensures a reduction of the workspace dead space.

The pump housing 5 is provided for example of plastic, whereby a cost-effective production is made possible. Like that 1 and 2 can be taken is between the engine 3 and the pump housing 5 a motor plate 30 arranged, which on a motor flange side 31 of the pump housing 5 is attached and from the engine 3 emits emitted EMC radiation.

The fastening of the engine 3 and the engine plate 30 on the pump housing 5 done by means of screw elements 32 , which directly into the pump house 5 be screwed, which at the same time for attachment of the motor-pump unit 1 can be provided in the vehicle.

Further is 2 to see that a motor shaft 33 at the same time serves as an eccentric shaft, which the crank drive 8th with the eccentrics 9 and the connecting rods 10 wearing. However, it is also possible a separate version of motor shaft and eccentric shaft.

Via one on the pump housing 5 provided connection 34 a connected brake booster is evacuated.

Next is 2 to find that for vibration optimization at the eccentrics 9 each one-piece a balance weight 35 is formed, wherein the eccentric 9 are produced as sintered components. This embodiment of the eccentric 9 conditioned on the one hand a cost-effective production and a simplified assembly, since the assembly of balancing weights 35 at the eccentrics 9 can be omitted by screwing, welding, etc., and on the other a further component reduction.

For further cost optimization, connecting rods can be used 36 the connecting rods 10 as sintered components and Pleuelschäfte 37 be provided from plastic, the attachment of the connecting rod shank 37 at the connecting rod eye 36 by overmolding an approach 38 of the connecting rod eye 36 he follows. The working membrane 4 can on the connecting rod shaft 37 be secured in a simple manner by friction welding. ball-bearing 39 be in the connecting rod eyes 36 pressed.

The operation and the basic structure of the embodiment of the invention described below do not differ from the operation and the basic structure of the according to the 1 to 4 described known motor-pump unit, so that only the essential parts of the invention are shown and described below. It is expressly noted that the invention is not in accordance with the 1 to 4 described embodiment of the motor-pump unit is limited. The invention may also find application in other forms of Verdrangerpumpen, for example in piston pumps.

As already described above and as in particular in 3 is shown, is the inlet valve 13 the well-known engine-pump unit 1 formed as a plate valve with a valve disc made of elastic material and is in a corresponding recess 40 of the upper lid 11 arranged, which forms so-called dead volume or Schadvolumen. However, this valve technology is not dead space-optimized. The size of the total dead volume determines, among other things, the suction times and the maximum final vacuum of the motor-pump unit 1 , The holding element 29 allows a small reduction of the working space dead space. However, increasing demands are made on manufacturing costs, service life and acoustic comfort, etc., which with the known motor-pump unit 1 can not be fulfilled.

To meet the increased requirements, the lower lid 41 the exemplary embodiments according to the 5 to 7 the motor-pump assembly according to the invention a recess 42 into which a valve disc 43 an intake valve 44 in an open position when the air is drawn in via an inlet channel 45 with a valve tongue 54 can dive into it. In this case, an inlet surface and a sealing surface of the inlet valve 44 and a shape of the recess 42 provided so matched to each other, that a reduction of the dead space of the intake valve 44 is reached. The known in the art, not dead space-optimized valve technology including the recess 40 in the upper lid 11 deleted, whereby the dead space can be reduced or optimized. A smaller dead space causes primarily a higher achievable final vacuum and secondarily faster Absaugzeiten, this at the same time advantageously advantageously a longer life of the pump, since it can be operated with shorter run times and thereby reduces the wear of the engine.

This is how the pump works 2 Normally switched on when in the vacuum brake booster a negative pressure of, for example, p _e = -0.6 bar (switch-on threshold). Only when a negative pressure of, for example, p _e = -0.8 bar (switch-off threshold) is reached, the pump 2 off. Since the turn-off threshold can be reached faster by means of the invention, the running time of the pump is reduced 2 with the described advantage.

Furthermore, depending on the requirement, instead of reducing the suction times, it is also possible to achieve noise reduction by reducing the rotational speed.

In the 5 to 7 two exemplary embodiments of the motor-pump unit according to the invention are shown, which are largely similar, with the difference being explicitly discussed. It shows 5 a partially longitudinal section of a first embodiment in a spatial representation and 6 a section of the inlet valve 44 in a longitudinal section of a second embodiment.

How out 6 it can be seen, is the recess 42 in the longitudinal section substantially triangular or wedge-shaped provided and goes into the workspace 7 over, so that no further recesses or channels are present, which can increase the dead volume.

The inlet channel 45 branches in the area of the recess 42 in both embodiments in at least two individual channels 46 in particular 5 and 6 can be clearly seen.

An optimal compromise between a necessary valve sealing surface d, with which the valve disc 43 in the region of the recess 42 sealingly abuts in a closed position, and utilizing an inlet surface of the inlet valve 44 can be achieved when the area of the valve tongues 54 minus the valve sealing surface d is optimally utilized with at least two inlet openings. In other words, it is therefore necessary to have a catheter of the triangular-shaped recess 42 optimally designed, whereby it is necessary to achieve the largest possible volume flow with the smallest possible dead space paired with sufficient sealing surface.

According to the first embodiment, the individual channels 46 in a valve cover 47 intended. This makes it possible, the inventive design of the intake valve 44 in the existing geometry of the known motor-pump unit 1 according to the 1 to 4 to integrate with only slight modifications. Are the individual channels 46 directly in the upper lid 48 provided, the valve cover can 47 eliminated and the number of components are reduced.

One to the lower lid 41 molded pin 49 passes through a centrally positioned opening for positioning 50 the valve cover 47 as well as an opening 51 the valve disc 43 ,

It is advantageous for the assembly, if the valve disc 15 the exhaust valve 19 and / or the valve disc 43 of the inlet valve 44 to the mold seal 24 are formed.

As seen from the top view of the valve disc 43 in 7 can be seen, is here partly only hinted recess 42 the lower lid 41 in cross-section of the pump 2 formed substantially semicircular and the valve tongue 54 of the inlet valve 44 is adapted to it accordingly provided semicircular.

The embodiment would be optimal if the recess 42 the lower lid 41 is designed as large as the folding area of the valve disc 43 ie as the valve tongue 54 , However, it is necessary for tolerance and assembly reasons, the immersion area of the valve tongue 54 by providing an insertion gap s as small as possible to increase a trouble-free operation of the intake valve 44 to enable. As in particular from 7 can be seen, the insertion gap s is a semicircular recess 53 the valve disc 43 educated.

Of course, the shape of the recess 42 and the valve tongue 54 (in cross-section of the pump 2 ) is not limited to a semicircle. Conceivable are other forms z. B. rectangular, wherein the features described above are designed to match each other to achieve the advantages described.

In the 5 shown, known Luftfuhrung in the inlet channel 45 creates turbulence and has sharp-edged transitions, leading to Absaugzeitverlusten. To the Luftfuhrung in the inlet channel 45 to improve, is the intake port 45 according to an embodiment of the invention, not shown, parallel to a in 2 shown center axis M in the upper lid 48 is formed and opens directly into the area of the individual channels 46 , as in 5 with the reference number 45 ' is indicated. Another advantage here is that the size of the work space cover 52 can be significantly reduced by the height h, causing the pump 2 Total can be downsized.

Around the inlet face of the inlet valve 44 that are made up of the surfaces of the individual channels 46 can, without further optimization of a significant deterioration of the valve sealing surface d, the inlet channel 45 in the region of the recess 42 in three triangular or semicircular arranged individual channels 46 branch, as in 5 in difference to 7 is shown.

LIST OF REFERENCE NUMBERS

1

Motor-pump unit

2

pump

3

engine

4

working diaphragm

5

pump housing

6

Working chamber cover

7

working space

8th

crank drive

9

eccentric

10

connecting rod

11

top cover

12

under cover

13

inlet channel

14

intake valve

15

valve disc

16

Single channel

17

Working chamber cover opening

18

Working chamber cover opening

19

outlet valve

20

valve disc

21

exhaust port

22

inner space

23

air outlet

24

shaped seal

25

sealing element

26

sealing element

27

sealing element

28

recess

29

retaining element

30

motor sheet

31

Motorflanschseite

32

screw

33

motor shaft

34

connection

35

balance weight

36

connecting rod

37

connecting rod shaft

38

approach

39

ball-bearing

40

recess

41

under cover

42

recess

43

valve disc

44

intake valve

45

inlet channel

46

Single channel

47

valve cover

48

top cover

49

spigot

50

opening

51

opening

52

Working chamber cover

53

recess

54

valve tongue

d

Valve sealing surface

H

Height

s

insertion gap

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been 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.

Cited patent literature

• DE 102009054499 A1 [0002]

Claims (9)

Motor pump unit for providing a vacuum comprising a pump ( 2 ) and one the pump ( 2 ) driving electric motor ( 3 ), whereby the pump ( 2 ) a pump housing ( 5 ) and at least one displacer element ( 4 ), which with one on the Pumpengehause ( 5 ) attached working space cover ( 6 ) a work space ( 7 ), whereby the working space ( 7 ) an inlet channel ( 45 ) with inlet valve ( 44 ) and an outlet channel ( 21 ) with exhaust valve ( 19 ), wherein the working space cover ( 6 ) an upper lid ( 48 ) and a lower lid ( 41 ), which are sealed together, wherein the valves ( 44 . 19 ) between upper cover ( 48 ) and lower lid ( 41 ) are provided and in each case a valve disc ( 15 . 43 ), characterized in that the lower lid ( 41 ) a recess ( 42 ), in which the valve disc ( 43 ) of the inlet valve ( 44 ) while sucking the air through the inlet channel ( 45 ) with a valve tongue ( 54 ), wherein an inlet surface and a sealing surface of the inlet valve ( 44 ) and a shape and a size of the recess of the lower lid ( 41 ) are provided so coordinated that the recess ( 42 ) of the inlet valve ( 44 ) is optimally utilized. Motor-pump unit according to claim 1, characterized in that the recess ( 42 ) is provided substantially wedge-shaped in the longitudinal section and into the working space ( 7 ) passes over. Motor-pump unit according to claim 1 or 2, characterized in that the inlet channel ( 45 ) in the region of the recess ( 42 ) into at least two individual channels ( 46 ) branches. Motor-pump unit according to claim 3, characterized in that the inlet channel ( 45 ) in the region of the recess ( 42 ) in three triangular or semicircular arranged individual channels ( 46 ) branches. Motor-pump unit according to one of the preceding claims, characterized in that the recess ( 42 ) of the lower lid ( 41 ) is formed in cross-section substantially semicircular and the valve tongue ( 54 ) of the inlet valve ( 44 ) is provided in accordance with semicircular. Motor-pump unit according to one of the preceding claims, characterized in that the inlet channel ( 45 ' ) parallel to a central axis (M) in the upper lid ( 48 ) and in the region of the individual channels ( 46 ) opens. Motor-pump unit according to one of the preceding claims, characterized in that for sealing the upper cover ( 11 ) and the lower lid ( 41 ) a molded seal ( 24 ) is provided, which has a plurality of sealing element elements and the valve discs ( 15 . 43 ) of inlet and / or outlet valve ( 19 . 44 ) to the molded seal ( 24 ) are formed. Motor-pump unit according to one of the preceding claims, characterized in that the pump ( 2 ) as a double membrane pump with two opposing working membranes ( 4 ) is provided, which in each case between a pump housing ( 5 ) and a work space lid ( 6 ) and thereby a work space ( 7 ) and which by means of a crank drive ( 8th ) are movable. Motor-pump unit according to one of the preceding claims, characterized in that the motor-pump unit is provided for providing negative pressure for a brake actuation device of a motor vehicle brake system with a vacuum brake booster.

Images