CN115943248A

CN115943248A - Pump assembly

Info

Publication number: CN115943248A
Application number: CN202180050927.4A
Authority: CN
Inventors: T·马洛戈斯基; O·弗朗西斯奇; S·蒂勒; H·G·杜; M·安德烈
Original assignee: GKN Sinter Metals Engineering GmbH
Current assignee: GKN Powder Metallurgy Engineering GmbH
Priority date: 2020-08-20
Filing date: 2021-08-17
Publication date: 2023-04-07
Also published as: EP3957822B1; SI3957822T1; EP3957822A1; US20230304494A1; WO2022038137A1

Abstract

A pump assembly (1) is disclosed, comprising at least a pump (2) having a pressure side (3) and a suction side (4) and a drive unit (5) for the pump (2), which is arranged in a common housing (6), wherein the drive unit (5) is an axial electric drive comprising a stator (7) connected to the housing (6) in a rotationally fixed manner and a rotor (8) arranged rotatably relative to the housing (6), wherein the rotor (8) is arranged with a first end side (9) opposite the stator (7) in the axial direction (10) and forms an outer conveying means (11) of the pump (2) and has a first conveying profile (13) at an inner circumferential surface (12), wherein an inner conveying means (15) of the pump (2) is arranged in the rotor (8) in the radial direction (14) and has a second conveying profile (17) at an outer circumferential surface (16) which interacts with the first conveying profile (13) for conveying a fluid (18).

Description

Pump assembly

Technical Field

The invention relates to a pump assembly comprising at least a pump and a drive unit for the pump, which are arranged in a common housing. The drive unit is an axial electric drive comprising a stator connected in a rotationally fixed manner to a housing and a rotor arranged rotatably relative to the housing. The rotor forms the outer conveying means of the pump and has a first conveying contour (for example a first toothing or vane of a vane pump) on the inner circumferential surface, wherein an inner conveying means of the pump is arranged in the rotor in the radial direction and has a second conveying contour (for example a second toothing or a cylindrical outer circumferential surface) on the outer circumferential surface, which interacts with the first conveying contour for conveying the fluid and, if necessary (in the case of a toothing), for driving the inner conveying means by the rotor.

Background

In the case of known pump embodiments, the rotor of the pump is arranged on a shaft which is led out of the housing of the pump assembly.

A pump assembly is known, for example, from DE 102015207748 A1. A fluid pump is described, which is driven by an electric motor. The pump rotor of the fluid pump is coupled to the electric motor. The electric motor is an axial motor whose motor rotor is also the pump rotor or drives the pump rotor. The pump rotor and the motor rotor are mounted in a common housing, in which the pump rotor and the motor rotor rotate in a disk-like manner integrated into a combined rotor, wherein the common housing has a fluid inlet and a fluid outlet relative to the combined rotor. The pump chamber or the fluid supply chamber is arranged in a closed manner in a common housing and the fluid inlet and the fluid outlet to the pump chamber are realized axially along the axis of rotation.

DE 102017113825 A1 discloses a pump assembly comprising at least one pump and a drive unit for the pump, which are arranged in a common housing. The drive unit is an axial flow electric drive which comprises a stator connected to the housing in a rotationally fixed manner and a rotor arranged rotatably relative to the housing. The rotor forms the outer conveying means of the pump, wherein the inner conveying means of the pump, which interacts with the first conveying contour for conveying the fluid and, if appropriate (in the case of a mesh), for the driving of the inner conveying means by the rotor, is arranged in the radial direction within the rotor. The inner delivery device is disposed on the outer sheath. No mechanical support of the external conveying means and the rotor is provided. In order to provide operation which is as leak-free as possible, the side walls surrounding the rotor are adjusted to a certain distance from one another via the traction means.

Disclosure of Invention

There is a continuing need to design such pumps further simplified and robust and durable to operate. In particular, a compact pump assembly is to be proposed which can be produced as easily as possible and which can be operated largely without wear.

These objects are facilitated by a pump assembly with the features according to patent claim 1. Advantageous developments are the subject matter of the dependent patent claims. The features listed in the patent claims can be combined with one another in a technically meaningful manner and can be supplemented by explanatory facts according to the description and/or by details according to the drawings, wherein further embodiments of the invention are indicated.

A pump assembly is proposed, comprising at least a pump with a pressure side and a suction side and a drive unit for the pump arranged in a common housing. The drive unit is an axial flow electric drive which comprises (precisely) a stator which is connected to the housing in a rotationally fixed manner and (precisely) a rotor which is arranged rotatably relative to the housing. The rotor is arranged with its first end side opposite the stator or the stator-side housing (i.e. the housing surrounding the stator) in the axial direction and forms an external delivery device of the pump. The outer conveying means has a first conveying profile at the inner circumferential surface. An inner conveying means of the pump is arranged in the radial direction inside the rotor, which has a second conveying profile at the outer circumferential surface, which second conveying profile interacts with the first conveying profile for conveying the fluid. The inner conveying means is supported on a centering element which is connected to the housing in a rotationally fixed manner. At least the rotor and the outer delivery means are arranged to be supported solely via the fluid (rotatable relative to the other parts of the pump assembly) delivered through the pump. At least between the first end side of the (rotor/outer conveying means) and the stator (or the stator-side housing) a first flow guide is arranged and connected to the pressure side, so that during operation of the pump assembly a gap between the first end side and the stator (or the stator-side housing) can be established by the fluid.

Electric drives usually comprise a stator and a rotor, which are arranged coaxially to each other. The rotor is referred to herein as the support for the permanent magnets, while the stator has coil assemblies. In the case of an axial flow motor, the rotor and the stator are arranged in succession, in particular in the axial direction. In this case, differently magnetized magnets are arranged on the rotor in an alternating manner in the circumferential direction.

The coil assembly of the stator has a core, for example made of SMC, which is surrounded by a current-carrying winding. Each core may be an element arranged to be magnetized when a current is directed through a current-carrying winding around the core. The windings conducting the current can be designed as coils.

SMCs are in particular composed of iron powder particles electrically isolated from each other. The core loss in SMC parts in alternating electric fields is generally low. In this connection, it therefore appears desirable to use SMC at least in part as a replacement for the most commonly used steel laminates (steel plates or electrical steel) in electrical machines. To form a part made of SMC, the particles are compacted and hardened. The SMC material is not sintered here. Instead, a temperature control below the melting temperature is achieved, but it is sufficient that the material permanently retains the set geometry.

The rotor of the electric drive can have permanent magnets, for example in the air gap, or can likewise have soft magnetic elements. Thus, a permanently excited synchronous or brushless direct current motor, abbreviated to BLDC, can be formed using permanent magnets as an electric drive, while a reluctance motor can be created as an electric motor in the form of an axial, radial or transverse construction, for example, using soft magnetic elements.

The rotor and the stator together in particular form a drive unit of the pump assembly.

The rotor has a first conveying contour (e.g., a first toothing) at the inner circumferential surface, via which the internal conveying means interacts with a second conveying contour (e.g., a second toothing) arranged at the outer circumferential surface of the internal conveying means for conveying the fluid. In the case of a configuration of the transport contour as an engagement, the inner transport means is driven via the outer transport means.

An own drive of the internal conveying means (for example via the shaft of the internal conveying means) is not necessary. The rotor and the internal delivery means together form, in particular, a pump of the pump assembly, which delivers fluid from the suction side or low-pressure side (fluid inlet) to the pressure side or high-pressure side (fluid outlet).

For such pump assemblies, for example, gerotor pumps and gerotor pumps (also referred to as crescent pumps) are suitable. Both pump types are characterized by rotors (inner and outer conveying means) with parallel, but radially spaced-apart axes of rotation of the meshing. The drive of one conveyor means is effected by the drive of the other conveyor means by means of the engagement portions being in engagement with one another.

As pump assembly, vane pumps and roller vane pumps can likewise be used, wherein the external delivery means comprise vanes or rollers as first delivery profiles movable in the radial direction relative to the axis of rotation. The second conveying profile is formed, for example, by a cylindrical outer circumferential surface of the inner conveying means, which cooperates with vanes or rollers.

The rotor and the conveying means are in particular arranged in a sliding bearing manner. During operation of the pump assembly, a fluid film is installed in the sliding bearing, in particular in the bearing acting in the opposite axial direction, which reduces the friction between the different moving components.

The rotor is in particular embodied coaxially or arranged unsupported or only supported in a sliding manner relative to the radial direction, in particular together with an external conveying means.

In operation of an axial electric drive, a force occurs in the axial direction, which causes the rotor to be attracted in the axial direction toward the stator. In the case of the embodiment with only one stator proposed here for a compact pump assembly, these forces can result in the rotating rotor contacting the stator or the housing surrounding the stator. This problem is exacerbated in the case of pump assemblies in which the rotor is not arranged on a shaft or is unsupported relative to the radial direction, since shaftless rotors can tilt more easily in operation. In the case of an arrangement of the rotor which is also only slightly skewed (the end faces of the rotor cannot usually be produced truly perpendicular to the axis of rotation), only partial contact between the rotor and the housing or the stator can occur. In this case, the rotor can have a material-removing effect on the housing or the stator, which can result in permanent damage to the pump assembly and can have a significantly limited service life.

In the case of the present pump assemblies, tilting of the rotor is furthermore prevented or reduced, in particular by the largest possible diameter of the rotor as a plane of the bearing acting in relation to the axial direction.

It is proposed here that a first flow guide is arranged between the first end face of the rotor and the stator or the stator-side housing and is connected to the pressure side, so that during operation of the pump assembly a gap between the first end face and the stator or the stator-side housing can be produced by the fluid. The pressure of the fluid set by the pump assembly on the pressure side is used here to set and maintain the distance in the axial direction between the first end side and the stator or the housing.

The spacing between the electromagnetic rotor part (magnet) and the electromagnetic stator part is in particular about 0.5mm and is in particular not significantly influenced by the fluid. In particular, the gap which is produced by the fluid and forms a gap between the rotor and the stator or the stator-side housing in the case of operation of the pump assembly is provided only for preventing friction and thus wear between the components. The gap (i.e. the distance formed by the fluid) is in particular significantly smaller than the distance between the electromagnetic components of the rotor and stator.

The first flow-guiding structure comprises in particular a channel structure which is formed at least on one of the surfaces forming the gap. These surfaces are formed at least by the first end side of the rotor and by the wall of the stator or of the housing which is situated opposite the first end side. In particular, then, there is precisely no gap with a constant gap size, but the gap size changes locally due to the channel structure implemented at least one surface. Via the channel structure, the fluid can be conveyed through the gap (and away via the gap), in particular at least in the radial direction. In particular, at least one flow channel for a fluid is provided here, along which the fluid is conveyed through the gap (and exits via the gap).

The fluid should in particular be fed substantially into the gap in order to reduce the friction between the components there. The transport of the fluid beyond the gap is in particular only a disadvantage which is necessary in the technical sense in order to transport the fluid into the gap. In particular, the fluid is to be conveyed specifically not beyond the gap, but rather the internal leakage is to be kept as low as possible.

In particular, a substantially constant pressure of the fluid is provided along the extension of the first flow guiding structure or along the channel structure in the gap. There is then no throttle section, in particular along the first flow guide structure or along the flow passage of the channel structure, which leads to a stepped or continuous pressure drop. In this case, throttle pressures may exist between the different flow channels of the channel structure.

In particular, the pump assembly is designed such that the axial forces acting between the stator and the rotor are (exactly) compensated on the pressure side by the pressure of the fluid which is generated during operation of the pump assembly. If necessary, the fluid pressure prevailing in the gap between the rotor and the stator can be adjusted via a (adjustable or constant) throttle.

In particular, the rotor extends over a certain width in the axial direction between a first end side facing the stator and an oppositely arranged second end side, wherein the first conveying profile and the second conveying profile respectively extend over the (same) width. The conveying profiles have in particular the same width, so that the end faces of the inner conveying means and the outer conveying means can be arranged aligned with one another in the radial direction.

In particular, the second conveying profile interacts with the first conveying profile for driving the inner conveying means, wherein the inner conveying means is rotatably mounted on the centering element. Here, too, the internal delivery means is supported only via the fluid delivered through the pump.

In particular, the first flow guide is likewise formed on the inner conveying means, so that here too a gap between the inner conveying means and the centering element can be ensured by the fluid in operation of the pump assembly. In particular, the first flow guide structure is configured differently here than between the rotor and the stator, since the axial forces act substantially between the rotor and the stator and are transmitted to the inner conveying means only via the contact friction of the conveying profile, starting from the rotor or from the outer conveying means.

In particular, the housing has a pressure line connected to the pressure side of the pump assembly at a second end side of the rotor, which is arranged opposite the first end side. In particular, the first flow guiding structure is connected (only) to the pressure tube via the centering element and/or via the delivery contour.

In particular, the fluid is conveyed (exclusively) from the pressure tube via the centering element to the first flow guiding structure.

In particular, the internal delivery device is rotatably mounted on a first outer circumferential surface of the centering element, wherein a second flow guide for connecting the pressure tube to the first flow guide is formed at least partially on the first outer circumferential surface. In particular, a hydrodynamic or hydrostatic support of the internal delivery device on the centering element can thus be achieved.

The second flow guide structure can be designed, in particular, according to the form of the first flow guide structure, wherein the second flow guide structure is provided for producing a gap extending parallel to the axis of rotation between the centering element and the inner conveying means.

In particular, the housing has a suction pipe connected to the suction side on a second end side of the rotor, which is arranged opposite the first end side. The fluid is conducted from the first flow guiding structure, which is to be referred to as leakage, in particular via the second outer circumferential surface of the rotor toward the intake pipe. This leakage is used in particular for lubricating the surfaces of the rotor and the housing which lie opposite one another.

With this pump assembly, fluid can be conveyed from the intake tube to the pressure tube via the conveying contour. The quantity of fluid used for lubrication and support of the components and for ensuring the gap can flow at least partially (as a leak) from the pressure side via the gap (back) to the suction side.

In particular, the fluid is conveyed from the pressure tube via the centering element and via the second flow guide to the first end side of the rotor. In particular, the fluid is conveyed (then, however, in particular only as a leakage) outwardly along the gap between the first end side and the stator and at least in the radial direction beyond the gap. The fluid then flows via the second outer circumferential surface of the rotor (i.e. between the housing and the rotor) to the second end side and to the suction side arranged there.

In particular, the rotor and the external conveying means are embodied in one piece, preferably in one piece, i.e. are produced together.

In particular, the rotating members (rotor, outer delivery means, inner delivery means) of the pump assembly are arranged contactlessly with respect to the stationary members (housing, stator, centering element) of the pump assembly, at least during operation of the pump assembly. In particular, there is no mechanical contact between the rotating member of the pump assembly and the stationary member of the pump assembly, at least during operation of the pump assembly.

In particular, all rotating components operate in a fluid. In particular, contact between a rotating component of the pump assembly and a stationary component of the pump assembly is prevented or a contactless arrangement is ensured by the fluid.

In particular, tolerances of the components which should furthermore be manufactured with high precision can be weakened, so that the costs for manufacturing the pump assembly can be reduced. The perpendicularity which is usually necessary between the axis of rotation and the first end side is implemented here in particular with little precision, since the gap between the rotor and the housing or stator is ensured via the fluid.

In particular in the case of such pump assemblies, the parallelism of the rotor end faces is the remaining important tolerance which should be implemented very precisely. Which can be manufactured very cost-effectively, for example by double disc grinding.

In particular, at least the rotor is produced powder-metallurgically. In particular, at least the stator is produced powder-metallurgically. In particular, the rotor is likewise produced by sintering.

Preferably, the pump is

A gerotor or gerotor pump (also called crescent pump) and the first delivery profile is a first mesh and the second delivery profile is a second mesh, wherein the meshes have different numbers of teeth from each other; or

-a vane pump or roller vane pump;

wherein the first axis of rotation of the rotor and the second axis of rotation of the inner transport means are arranged parallel to each other and spaced apart from each other in the radial direction.

In particular, the pump assembly has only static seals, i.e. only seals arranged between parts arranged in a rotationally fixed manner. Thus, a reliable and durable seal can be ensured by only static seals.

The pump assembly has in particular the following operating parameters:

rated power consumption (in watts):

0 to 2000; preferably 50 to 200;

nominal maximum working pressure (in bar):

0 to 100; preferably 4 to 12;

volumetric efficiency (in liters/minute):

0 to 50; preferably 3 to 12;

rotational speed of the rotor (in revolutions per minute):

0 to 7000; preferably 1000 to 4000.

The gap between the first end face of the rotor (in particular not in the region of the magnets) and the housing or the stator, i.e. in particular the gap forming a plain bearing or the gap forming the first flow-guiding structure, is in particular at least 0.003 mm, preferably at most 0.1 mm, particularly preferably at most 0.05 mm or even at most 0.01 mm during operation of the pump assembly.

In particular, the gap between the magnet and the housing or stator is at least 0.2 mm, preferably at least 0.3 mm. Preferably, the gap in this region is at most 1.5mm, particularly preferably at most 1.0mm, in particular 0.3 to 0.7mm.

The use of the indefinite articles "a", "an" and "an" should be understood as such and not as numerals, especially in the context of the patent claims and the recitations therein. Accordingly, the concept or component introduced in this way can be understood in such a way that it is present at least once and in particular, however, also a plurality of times.

As a precautionary measure, it should be noted that the numbers ("first", "second", "a.,.) used here are primarily (only) used to distinguish a plurality of similar objects, dimensions or processes, i.e. in particular the relationship and/or the sequence of these objects, dimensions or processes to one another is not mandatory to be specified. If relationships and/or sequences are necessary, such are explicitly stated herein or are apparent to one of ordinary skill in the art in view of the specifically described design. If a component may appear multiple times ("at least once"), the description with respect to one of these components may apply equally to all or portions of most of these components, although this is not mandatory.

Drawings

The present invention and the technical scope will be further explained below with reference to the accompanying drawings. It should be noted that the present invention should not be limited by the cited examples, as follows. In particular, it is equally possible, if not explicitly shown otherwise, to extract some aspects of the facts illustrated in the figures and combine them with other constituents and knowledge from this description. In particular, it should be pointed out that the drawings and in particular the dimensional ratios shown are only schematic. Wherein:

FIG. 1: a pump assembly is shown in perspective view, exploded illustration;

FIG. 2: a pump assembly is shown in a cross-sectional side view with a graphical representation of the flow profile of the fluid from the pressure side to the suction side;

FIG. 3: the pump assembly is shown in a cross-sectional side view with a flow progression from the pressure side to the first end side;

FIG. 4 is a schematic view of: a part of the pump assembly is shown in perspective view with a part of the flow direction according to fig. 3;

FIG. 5: a part of the pump assembly is shown in a perspective view with a further part according to the flow profile of fig. 3 coupled to the flow profile of fig. 4;

FIG. 6: a part of the pump assembly according to fig. 3 is shown in a perspective view;

FIG. 7: a part of the pump assembly is shown in a perspective view with the part of the flow course according to fig. 3 and another part of the flow course coupled to the flow course according to fig. 5;

FIG. 8: the pump assembly according to fig. 2 is shown in a sectional perspective view.

Detailed Description

Fig. 1 shows a pump assembly 1 in a perspective view, exploded illustration. Fig. 2 shows the pump assembly 1 in a sectional side view with a representation of the flow profile 34 of the fluid 18 from the pressure side 3 to the suction side 4. Fig. 3 shows the pump assembly 1 in a sectional side view with a flow profile 34 from the pressure side 3 to the first end side 9. Fig. 4 shows a part of the pump assembly 1 in a perspective view with a part of the flow course 34 according to fig. 3. Fig. 5 shows a part of the pump assembly 1 in a perspective view with another part of the flow profile 34 according to fig. 3 coupled to the flow profile 34 according to fig. 4. Fig. 6 shows a part of the pump assembly 1 according to fig. 3 in a perspective view. Fig. 7 shows a part of the pump assembly 1 in a perspective view with a part of the flow profile 34 according to fig. 3 and another part of the flow profile 34 coupled to the flow profile 34 according to fig. 5. Fig. 8 shows the pump assembly 1 according to fig. 2 in a sectional perspective view. Fig. 1 to 8 are described together below.

Fig. 1 and 3 to 8 are shown only with respect to the rotor 8, the outer conveying means 11 and the inner conveying means 15 and are not according to the invention. Here, the rotor 8 is shown as an assembly of two components. The conveying

contour

13,17 of the conveying

means

11,15 does not extend as far as the first end side 9, but rather extends over a smaller width 23 than the rotor 8.

The pump assembly 1 comprises a pump 2 with a pressure side 3 and a suction side 4 and a drive unit 5 for the pump 2, which are arranged in a common housing 6. The drive unit 5 is an axial flow electric drive, which comprises precisely one stator 7 connected to the housing 6 in a rotationally fixed manner and precisely one rotor 8 arranged rotatably relative to the housing 6. The rotor 8 is arranged with a first end side 9 opposite the stator 7 in the axial direction 10 and forms an external delivery device 11 of the pump 2. The outer conveying means 11 have a first conveying profile 13 at the inner circumferential face 12. Arranged in the radial direction 14 within the rotor 8 is an internal conveying means 15 of the pump 2, which has a second conveying profile 17 at the outer circumferential surface 16, which cooperates with the first conveying profile 13 for conveying a fluid 18. The inner conveying means 15 is supported on a centering element 19 which is connected to the housing 6 in a rotationally fixed manner. The rotor 8 and the outer delivery means 11 are rotatably supported relative to the other parts of the pump assembly 1 only via the fluid 18 delivered by the pump 2. A first flow guiding structure 20 is arranged between the first end side 9 and the stator 7 and is connected to the pressure side 3, so that a gap 21 between the first end side 9 and the stator 7 can be established by the fluid 18 during operation of the electric drive.

The coil assembly of the stator 7 has a core 32, for example made of SMC, which is surrounded by a current-carrying winding 31.

The rotor 8 of the electric drive has magnets 33. The core 32 and the winding 31 are arranged spaced apart from the magnet 33 by a gap 21.

The rotor 8 has a first conveying contour 13 (here a first engagement) at the inner circumferential surface 12, via which the internal conveying means 15 interacts with a second conveying contour 17 (here a second engagement) arranged at the outer circumferential surface 16 of the inner circumferential surface 15 for conveying the fluid 18. In the case of a

transport profile

13,17 configured as an engagement, the inner transport means 15 is driven via the outer transport means 11. The first axis of rotation 29 of the rotor 8 (and the outer conveying means 11) and the second axis of rotation 30 of the inner conveying means 15 are arranged parallel to one another and spaced apart from one another in the radial direction 14. The pump 2 is implemented as a gerotor pump.

In operation of the axial electric drive, a force occurs in the axial direction 10, which causes an attraction of the rotor 8 in the axial direction 10 toward the stator 7. A gap 21 between the first end side 9 and the stator 7 is set by the fluid 18 during operation of the electric drive by means of a first flow-guiding structure 20 arranged between the first end side 9 and the stator 7 and connected to the pressure side 3. The pressure of the fluid 18 set on the pressure side 3 by the pump assembly 1 is used here to set and maintain the spacing in the axial direction 10 between the first end side 9 and the stator 7 or the housing 6.

The rotor 8 extends in the axial direction 10 between a first end side 9 facing the stator 7 and an oppositely arranged second end side 22 over a width 23, wherein the first conveying profile 13 and the second conveying profile 17 respectively extend over the same width 23, according to fig. 2 over the width 23 of the rotor 8 and according to fig. 1 and 3 to 8 (not according to the invention) over only a part of the width 23 of the rotor 8.

The housing 6 has, on a second end side 22 of the rotor 8, which is arranged opposite the first end side 9, a pressure pipe 24 (see fig. 4) connected to the pressure side 3, wherein the first flow-guiding structure 20 is connected to the pressure pipe 24 via a centering element 19 and/or via a conveying contour 13,17 (see fig. 2, to the left of the axis of rotation 29,30: the connection between the pressure pipe 24 and the first flow-guiding structure 20 likewise is only via the conveying contour 13,17).

The fluid 18 is conveyed from the pressure pipe 24 via the centering element 19 and/or the conveying

profile

13,17 in the flow direction 34 toward the first flow-directing structure 20 (see fig. 2 to 8).

The inner conveying means 15 is rotatably mounted on a first outer circumferential surface 25 of the centering element 19, wherein a second flow guide 26 for connecting the pressure tube 24 to the first flow guide 20 is formed on the first outer circumferential surface 25.

The housing 6 has a suction pipe 27 connected to the suction side 4 at a second end side 22 of the rotor 8, which is arranged opposite the first end side 9, wherein a leakage of fluid from the first flow guiding structure 20 via a second outer circumferential surface 28 of the rotor 8 to the suction pipe 27 is achieved.

The fluid 18 is conveyed from the pressure tube 24 via the centering element 19 and via the second flow guidance 26 and, if necessary, via the conveying

contour

13,17 to the first end side 9 of the rotor 8 (see fig. 2 to 8). The fluid 18 is then conveyed outwards along the gap 21 between the first end side 9 and the stator 7 and at least in the radial direction 14 through the gap 21 and as a leakage out through the gap 21 (see 2,3,7 and 8). The fluid 18 then flows as a leak via the second outer circumferential surface 28 of the rotor 8 (i.e. between the housing 6 and the rotor 8) towards the second end side 22 and towards the suction side 4 arranged there (see fig. 2 and 8).

The component rotor 8 shown in fig. 2 and the external conveying means 11 are embodied together in one piece and thus according to the invention.

In the remaining fig. 1 and 3 to 8 (which are not in accordance with the invention only in this respect), the rotor 8 comprises two components which are connected to one another via a positively locking connection with respect to the circumferential direction 35. One component of the rotor 8 constitutes the first end side 9 and comprises the magnet 33, the other component comprising the external transportation means 11.

At least in operation of the pump assembly 1, the rotating components (rotor 8, including outer delivery means 11, inner delivery means 15) of the pump assembly 1 are arranged contactlessly with respect to the stationary components (housing 6, stator 7, centering element 19) of the pump assembly 1. Thus, all rotating members are moved in the fluid 18. Contact between the rotating components of the pump assembly 1 and the stationary components of the pump assembly 1 is prevented or a contactless arrangement is ensured by the fluid 18.

List of reference numerals

1 Pump Assembly

2 Pump

3 pressure side

4 suction side

5 drive unit

6 casing

7 stator

8 rotor

9 first end side

10 axial direction

11 external transport device

12 inner circumferential surface

13 first conveying profile

14 radial direction

15 internal conveying device

16 outer circumferential surface

17 second conveying profile

18 fluid

19 centering element

20 first flow guide structure

21 gap

22 second end side

23 width

24 pressure pipe

25 first outer circumferential surface

26 second flow guide structure

27 suction pipe

28 second outer circumferential surface

29 first axis of rotation

30 second axis of rotation

31 winding

32 core part

33 magnet

34 flow direction of the flow

35 in the peripheral direction

Claims

1. Pump assembly (1) comprising at least a pump (2) having a pressure side (3) and a suction side (4) and a drive unit (5) for the pump (2), which is arranged in a common housing (6), wherein the drive unit (5) is an axial electric drive comprising a stator (7) which is connected to the housing (6) in a rotationally fixed manner and a rotor (8) which is arranged rotatably relative to the housing (6), wherein the rotor (8) is arranged with a first end side (9) in the axial direction (10) opposite the stator (7) and forms an outer conveying means (11) of the pump (2) and has a first conveying profile (13) at an inner circumferential surface (12), wherein an inner conveying means (15) of the pump (2) is arranged in the rotor (8) in the radial direction (14) and has a second conveying profile (17) at an outer circumferential surface (16) which cooperates with the first conveying profile (13) for conveying a fluid (18); wherein the inner conveying means (15) is supported on a centering element (19) connected in a rotationally fixed manner to the housing (6); wherein at least the rotor (8) and the external delivery means (11) are provided for bearing only via the fluid (18) delivered through the pump (2); wherein a first flow-guiding structure (20) is arranged at least between the first end side (9) and the stator (7) and is connected to the pressure side (3) such that a gap (21) between the first end side (9) and the stator (7) can be generated by the fluid (18) in operation of the electric drive.

2. Pump assembly (1) according to claim 1, wherein the rotor (8) extends over a width (23) in the axial direction (10) between a first end side (9) facing the stator (7) and an oppositely arranged second end side (22), wherein the first and second delivery profiles (13, 17) respectively extend over the width (23).

3. Pump assembly (1) according to one of the preceding patent claims, wherein the second delivery profile (17) co-acts with the first delivery profile (13) for driving the inner delivery means (15), wherein the inner delivery means (15) is rotatably supported on the centering element (19); wherein the internal conveying means (15) is likewise supported only via the fluid (18) conveyed through the pump (2).

4. Pump assembly (1) according to one of the preceding patent claims, wherein the housing (6) has a pressure tube (24) connected with the pressure side (3) at a second end side (22) of the rotor (8) arranged opposite the first end side (9), wherein the first flow guiding structure (20) is connected with the pressure tube (24) via the centering element (19).

5. Pump assembly (1) according to claim 4, wherein the internal delivery means (15) is rotatably supported on a first outer circumferential surface (25) of the centering element (19), wherein a second flow guiding structure (26) for connecting the pressure tube (24) with the first flow guiding structure (20) is at least partially formed on the first outer circumferential surface (25).

6. Pump assembly (1) according to one of the preceding patent claims, wherein the housing (6) has a suction duct (27) connected to the suction side (4) at a second end side (22) of the rotor (8) arranged opposite the first end side (9), wherein the leakage of the fluid from the first flow guiding structure (20) takes place via a second outer circumferential face (28) of the rotor (8) towards the suction duct (27).

7. Pump assembly (1) according to one of the preceding patent claims, wherein the rotor (8) and the external delivery means (11) are implemented in one piece.

8. The pump assembly (1) according to any one of the preceding patent claims, wherein the rotating member (8,11,15) of the pump assembly (1) is arranged contactless with respect to the stationary member (6,7,19) of the pump assembly (1) at least in operation of the pump assembly (1).

9. The pump assembly (1) according to any one of the preceding patent claims, wherein at least the rotor (8) is powder metallurgically manufactured.

10. Pump assembly (1) according to any one of the preceding patent claims, wherein the pump (2)

-is a gerotor pump or a gerotor pump and the first delivery profile (13) is a first mesh and the second delivery profile (17) is a second mesh, wherein the meshes have a different number of teeth from each other; or

-is a vane pump or roller vane pump;

and wherein the first axis of rotation (29) of the rotor (8) and the second axis of rotation (30) of the inner conveying means (15) are arranged parallel to each other and spaced apart from each other in the radial direction (14).