EP4092273A1 - Pump for a water-conducting domestic appliance and water-conducting domestic appliance with such a pump - Google Patents

Abstract

An impeller pump for a dishwasher has a pump housing made up of a pump upper part, a pump lower part and a pump outer wall, in which a pump chamber is arranged. It has a pump inlet into the pump housing and a pump outlet from the pump housing as well as a heating device that forms the pump outer wall and a pump drive with a drive rotor, a drive stator with a stator winding and a bearing shaft. The bearing shaft is fixed to the pump housing and the drive rotor is fixed to the drive rotor and they are rotatably arranged on the bearing shaft. The stator winding is arranged on an area of the lower part of the pump that borders the pump chamber on its other side in the radial direction outwards, so that only one wall of the lower part of the pump runs between the pump chamber and the stator winding, so that the stator winding is surrounded by the pump chamber like a ring. So it can be well cooled by water in the pump chamber.

Description

Field of application and state of the art

The invention relates to a pump for a water-bearing household appliance and a water-bearing household appliance with such a pump, the pump being an impeller pump.

From the WO 2014/198427 A1 such an impeller pump for a dishwasher is known as a water-bearing household appliance. The pump or a pump drive for it is designed as a so-called wet rotor, and a drive rotor is firmly connected to an impeller by means of a shaft. The drive rotor is therefore partially surrounded by or comes into contact with water from the pump chamber. Furthermore, the drive rotor has ferromagnetic material. A drive stator with a corresponding stator winding runs radially on the outside around the drive rotor.

task and solution

The invention is based on the object of creating a pump as mentioned at the outset and a water-conducting household appliance provided with such a pump, with which problems of the prior art can be solved and in particular it is possible to create a practical and easy-to-install pump.

This object is achieved by a pump having the features of claim 1 and by a water-carrying household appliance having the features of claim 16. Advantageous and preferred configurations of the invention are the subject matter of the other claims and are explained in more detail below. Some of the features are only described for the pump or only for the water-bearing household appliance. However, independently of this, they should be able to apply independently both to such a pump and to such a water-bearing household appliance. The wording of the claims is made part of the content of the description by express reference.

The pump is designed as an impeller pump and has a pump housing and a pump chamber therein. The pump housing is made up of at least three parts, namely a pump upper part, a pump lower part and an outer pump wall. The pump chamber itself is formed by the upper part of the pump and the lower part of the pump as well as the outer wall of the pump, and is therefore partially formed directly by the pump housing. Advantageous the pump housing has numerous other parts or some of the parts mentioned, in particular the pump upper part and the pump lower part, go beyond this functionally and structurally and serve even more functions than just those required for the pump chamber. The pump outer wall is advantageously only the peripheral boundary for the pump chamber between the upper pump part and the lower pump part, in particular it can be tubular. Furthermore, a pump inlet into the pump housing and a pump outlet out of the pump housing are provided, with the pump inlet advantageously running directly into the pump chamber. The pump outlet advantageously runs out of the pump chamber. Due to the configuration as an impeller pump, the pump inlet is at least in the pump chamber in the axial direction of the pump. The pump outlet runs at least out of the pump chamber at an angle thereto, advantageously between 60° and 120°, particularly advantageously almost or completely tangentially or as an externally intersecting secant. The pump has a heating device which is formed on the outer wall of the pump or which itself forms the outer wall of the pump. Furthermore, the pump has a pump drive, which has a drive rotor and a drive stator in a conventional manner. A bearing shaft is also provided which runs along the longitudinal axial axis of the pump. The drive stator has a stator winding, so that the drive rotor is not electrically contacted. The entire pump drive is designed as a wet rotor, so that the drive rotor runs in the water, so to speak, or is at least partially surrounded by water and is therefore also connected to the pump chamber for water conduction or is in the pump chamber.

According to the invention, the bearing shaft is arranged in a fixed and immovable manner on the pump housing; detailed options are explained in more detail below. The drive rotor is rotatably arranged on the bearing shaft, advantageously by means of suitable bearings. The drive rotor can be arranged or run on a floor or just above a floor of the lower part of the pump. The impeller is firmly connected to the drive rotor and is therefore also rotatably mounted on the rotary shaft. Furthermore, due to the fixed connection, it is immovable relative to the drive rotor. It can be designed or manufactured at least partially together with this, which will be explained in more detail below.

Furthermore, the stator winding is arranged on an area of the lower part of the pump that borders the pump chamber outwards in the radial direction, i.e. on its other side, in such a way that essentially only one wall of the lower part of the pump runs between the pump chamber in this area and the stator winding or only one or a single wall of the lower part of the pump runs here, in particular no other components between the pump chamber and the stator winding in this area. Thus, the pump chamber is in pulled so far down in the axial direction of the pump or the drive stator is shifted so far up towards the impeller that the drive stator or its stator winding are also surrounded by the pump chamber in the radial direction. This allows for good cooling of the stator winding by the water in the pump chamber. Furthermore, a compact design in the axial direction can be achieved in this way. The stator winding is thus surrounded by the pump chamber like a ring. It is important to ensure that the drive stator is sealed off from the pump chamber.

Thus, a pump can be created by the invention, which allows an advantageous cooling of the drive stator or its stator winding. Cooling of the drive rotor can advantageously take place in that it is designed as a wet rotor and is therefore well cooled anyway. The design, which is compact in the axial direction, enables the pump to have a relatively short length and thus an advantageous arrangement in the household appliance, without taking up an unnecessarily large amount of space.

In an advantageous embodiment of the invention, the drive stator has a stator winding running radially on the outside and means for guiding the magnetic field radially inside it. These means for guiding the magnetic field are advantageously designed as a laminated stator core, as is known per se. This structure has the advantage that the magnetic field towards the drive rotor, which is arranged radially inside it and surrounded by the drive stator, can be designed as well as possible or can be designed as desired. Furthermore, the stator winding, which runs radially on the outside, is therefore as close as possible to the pump chamber surrounding it and can therefore be cooled as well as possible by the water that is located there and circulates. For example, it is possible to insert or mount the drive stator in a corresponding bulge in the pump housing or the lower part of the pump. This can be open downwards towards or in the direction away from the upper part of the pump, so that an electrical connection to the stator winding can be made as well and as simply as possible. The drive stator is therefore preferably located, viewed in the radial direction, between the drive rotor, which is radially inside of it, and the pump chamber or a part or section of the pump chamber, which is arranged radially outside of it. In particular, that area of the pump chamber that merges completely or at least partially into the pump outlet is located radially outside of the drive stator.

While the drive stator has the mentioned means for guiding the magnetic field in addition to the stator winding, the drive rotor can have ferromagnetic material or a laminated rotor core. The drive rotor advantageously has ferromagnetic material, which can be embedded in plastic or surrounded by plastic walls, for example. This can be a so-called rotor housing, so that this ferromagnetic material or rotor lamination stack cannot come into contact with water. Alternatively, a ready-made ferromagnetic material, for example in the form of a ring or part of a ring, can be overmoulded with plastic or inserted and glued into prefabricated plastic parts, for example in the form of a shell. As yet another alternative, the ferromagnetic material of the drive rotor can be admixed with or mixed with plastic. The entire drive rotor can thus be manufactured in a casting process or plastic injection molding process. At least part of the impeller can possibly also be produced in the same step, in particular a lower cover disk, which will be explained below.

In a possible embodiment of the invention, the pump chamber does not run completely outside of the drive stator in the axial length thereof, but only partially. However, it should advantageously run along at least 70% of its axial length, in particular along at least 90%. The best possible cooling of the drive stator or its stator winding can then be achieved by the water in the pump chamber. However, the pump chamber does not have to run completely on the outside of the drive stator or the stator winding.

In a further advantageous embodiment of the invention, an upper side or an upper end face of the drive stator or the stator winding also rests against the pump chamber. In particular, the upper end face of the drive stator is separated from the pump chamber by the wall of the lower part of the pump. This means that the water in the pump chamber can also be used for cooling here, so that the drive stator can even be cooled on two sides.

It is advantageously provided that the pump inlet runs centrally and axially into the pump housing and into the pump chamber. The impeller can then be connected directly to the pump inlet. The pump inlet can be designed at least partially in the form of a tube or in the manner of a pipe socket. In an advantageous development of the invention, the pump inlet can be formed on the upper part of the pump itself or can be formed by this. The pump outlet, in turn, can, independently of this, be formed on the lower part of the pump and, seen in the axial length of the pump, can be arranged at least below the impeller. The pump outlet may be even further away from the pump inlet along the axial length of the pump, for example at least partially below the drive stator. However, it does not have to lie completely below the drive stator, which in turn can limit the overall axial length of the pump.

The pump outer wall is advantageously tubular, in particular cylindrical or round-cylindrical. The tube section may be cut straight at both ends and perpendicular to its axial length. Advantageously, the outer wall of the pump also runs concentrically to the longitudinal center axis of the pump and to the bearing shaft.

Heating conductors can be arranged on an outside of the pump outer wall in order to form the heating device. These heating conductors can be in the form of thin-film or thick-film heating devices, alternatively using other heating means such as tubular heating elements. It is thus possible for the heating conductors to be separated from the water in the pump chamber by the outer wall of the pump. A thin pump outer wall, for example 0.1 mm to 3 mm, allows very good heat transfer into the water in the pump chamber. For example, the outer wall of the pump can be made of metal, for example as a metal tube, and the aforementioned heating conductors can be printed on as a thin-film or thick-film heating device. For this purpose, for example, reference is made to the above-mentioned WO 2014/198427 A1 as well as the DE 10 2011 003 464 A1 referred.

In an embodiment of the invention, the bearing shaft is fixedly arranged on the lower part of the pump by being pressed or even injected into it. The bearing shaft is advantageously made of metal, alternatively it can also be made of plastic, for example a different plastic than the rest of the lower part of the pump, preferably stable fiber-reinforced plastic. Corrosion problems can thus also be reduced.

The drive rotor, which is rotatable relative to the bearing shaft, is advantageously rotatably mounted thereon in its lower region by means of a radial bearing. A further radial bearing can be provided in the upper part of the drive rotor, possibly also on an impeller arranged above it which is fixedly connected to it. However, this does not have to be the case, especially if an axial bearing at the upper end of the impeller also causes a certain radial bearing. In any case, the arrangement of the thrust bearing at the top of the impeller has the advantage that it can easily rest against a counter-thrust bearing. This is mounted in the pump inlet, advantageously by means of radially running webs. The counter-axial bearing and the axial bearing are therefore in the incoming flow of water, but at the same time this can cause cooling and possibly also lubrication, and other points are even more complicated. Furthermore, no special bearing shaft has to be provided, but this can be designed very simply and straight. It is thus possible to limit oneself to a total of two bearings, namely the radial bearing and the axial bearing.

A radial bearing can be made of plastic on the one hand, and of suitable ceramic or a sintered material on the other hand. It can be clamped or glued to the drive rotor, alternatively it can also be injected. In order to be able to design it simply, it should be designed in such a way that it does not have to or cannot absorb any forces in the axial direction. It is also possible to provide sealed roller bearings, in particular ball bearings or needle bearings, which usually have even lower friction. These should then be well sealed.

The axial bearing advantageously consists of a different material than the impeller on which it is arranged. It can be manufactured separately and placed on the impeller or on the drive rotor. It may also be molded onto the impeller, for example in a two-component injection molding process.

In general, the thrust bearing can have a convex tip on the impeller. This can be convexly curved in the direction from the impeller to the pump inlet, and if the counter-thrust bearing is also curved in a similar way, radial centering can be made possible in addition to the axial contact. Since the axial bearing is arranged at the point of the rotating part that is furthest away or is arranged highest, the best possible balance of forces is available for both the axial bearing and the radial bearing for a desired, defined bearing of the assembly of drive rotor and impeller given. Alternatively, it is also conceivable to curve the axial bearing on the impeller and the counter-axial bearing in the opposite direction, which also allows radial bearing as centering in addition to axial bearing. An axial bearing, possibly also the counter-axial bearing, can have graphite-containing plastic or be made of graphite-containing plastic. It can be injected or injected both on the impeller and on the upper part of the pump, possibly also be attached later, for example glued and/or clamped.

In an alternative configuration, an axial bearing for the drive rotor can be provided on its radial bearing. Only a single bearing needs to be provided, which, however, would have to be designed in a significantly more complex manner.

Provision can be made for the assembly of drive rotor and impeller to have a certain movement path in the axial direction of the pump, for example 0.1 mm to 10 mm, advantageously 0.5 mm to 5 mm. During operation of the pump, the impeller is usually pulled in the axial direction towards the pump inlet due to its pump function, so that the axial bearing described above is sufficient to move it here in support in the axial direction. For this reason, when the drive rotor/impeller is stationary, there can even be a distance between the axial bearing and the counter-axial bearing, advantageously in the aforementioned range, particularly advantageously between 0.5 mm and 3 mm. It can also be achieved in this way that the two bearings mentioned, namely axial bearings and radial bearings, are sufficient.

If the drive rotor and the impeller are not rotating, it can be provided that a free end or an end surface of the bearing shaft bears against an end or an inner end surface of a receiving opening on the impeller, into which the bearing shaft is inserted. In this way it can be achieved that the underside of the drive rotor does not or never rests against the upper side of the lower part of the pump, but that a distance is provided in between. This distance can be between 1 mm and 10 mm, for example. In this way it can be achieved that the drive rotor can still rotate when the pump is dry, and a bearing and thus also friction arises only between the end of the bearing shaft and the said inner end face of the impeller. This can be absorbed well here, for example through structural design or appropriate choice of material. In any case, this can prevent the underside of the drive rotor from rubbing or scratching the lower part of the pump. Realistically, it is not possible to prevent the pump from running dry, but at least damage that may result from this can be avoided.

In a further embodiment of the invention, a structural unit made up of impeller and drive rotor can be formed at least partially in one piece in such a way that at least one lower part of the impeller is advantageously formed together with the rotor housing or the entire drive rotor. Such a lower part of the impeller can include not only a type of lower impeller cover plate, but also an area of the impeller that is usually raised radially on the inside. This area, which is raised radially on the inside, can form or have the above-described axial bearing at its highest point.

In an advantageous embodiment, an upper part of the impeller can then be designed as a separate part, advantageously made of plastic, and attached to the lower part of the impeller. A fastening should not be detachable here, gluing, welding, ultrasonic welding or friction welding are possible. This upper part of the impeller advantageously also has the impeller blades at least partially, advantageously entirely. A mold and thus also a manufacturing process for the lower part of the impeller, including the drive rotor or rotor housing, can be designed in a simple manner.

Alternatively, the impeller can be manufactured separately from the drive rotor, for example in a single-component or multi-component injection molding process. The impeller can be advantageous be manufactured in one piece, alternatively in two parts with a lower part and an upper part, the impeller blades being formed on one of the two parts. The impeller connected to it is then connected to the drive rotor to form a structural unit, for example glued or welded in one of the aforementioned ways.

In a preferred embodiment of the invention, the pump outlet can be provided in an area of the pump or the pump chamber which, viewed in the longitudinal direction of the pump, is located furthest away from the pump inlet. This can advantageously also be the deepest part of the pump chamber, so that with a possible vertical arrangement of the pump, water automatically drains out of the pump chamber, at least if a drain or the like. not by means of a valve or the like. is locked. In this way, hygienic problems within the pump or within the pump chamber can be reduced.

In a further possible advantageous embodiment of the invention, the pump inlet can be designed to be increasingly widened upwards or in the direction away from the impeller or the pump chamber, in addition to a possible aforementioned tubular shape. A kind of flat, wide funnel can be formed here. A widening advantageously takes place to a diameter that is even larger than the pump chamber. In this way, a sump for a dishwasher or a washing machine can be formed so that it does not have to be manufactured as a separate part and then connected to the pump inlet in a watertight manner.

Preferably, at least one guide vane can be provided on the lower part of the pump, which protrudes into the pump chamber. Such a guide vane is advantageously provided on a wall that runs radially outwards outside and possibly along the drive stator, advantageously in the axial direction. Such a guide vane is particularly preferably produced in one piece and in one piece with the lower part of the pump. In the direction of circulation of the pumped water, it can have a slope downwards or towards the pump outlet and serve to control the water flow within the pump chamber.

In a possible development of the invention, latching devices can be provided on the pump or on the pump housing in order to hold it together. Advantageously, the locking devices are integrally formed in one piece and all run equally either from the upper part of the pump to the lower part of the pump or vice versa. Thus, the latching devices can be integrally and integrally connected at one end to one of the two parts of the pump housing or formed thereon. The other free end is snapped onto the other part. Then separate means can be dispensed with to hold the pump housing together.

In a preferred embodiment of the invention, the pump is installed vertically in a water-bearing household appliance, so that the bearing shaft runs vertically. It is advantageously provided that the pump inlet points upwards or is arranged at the top and thus forms the highest part of the pump. As has been described above, the pump outlet then forms the lowest point of the pump chamber, for example for an advantageous automatic, extensive emptying of the pump chamber. The pump is preferably arranged directly below a treatment chamber of the water-bearing household appliance, in particular when installed in a dishwasher, so that no interposed valves or the like are required here either. are necessary.

These and other features emerge from the claims, the description and the drawings, with the individual features being realized individually or in combination in the form of sub-combinations in one embodiment of the invention and in other areas and are advantageous and protectable in their own right Designs may represent for which protection is claimed here. The subdivision of the application into subheadings and individual sections does not limit the general validity of the statements made under them.

Brief description of the drawings

Fig. 1

eine schematische Ansicht einer Spülmaschine als erfindungsgemäßes Haushaltsgerät mit einer erfindungsgemäßen Pumpe,

Fig. 2

einen Schnitt durch die erfindungsgemäße Pumpe und

Fig. 3

einen vergrößerten Schnitt durch einen abgewandelten Impeller für erfindungsgemäße Pumpe.

Exemplary embodiments of the invention are shown in the drawings and are explained in more detail below. In the drawings show:

1

a schematic view of a dishwasher as a household appliance according to the invention with a pump according to the invention,

2

a section through the pump according to the invention and

3

an enlarged section through a modified impeller for the pump according to the invention.

Detailed description of the exemplary embodiments

In the 1 a dishwasher 11 is shown schematically as a household appliance according to the invention with a housing 12 and a rinsing chamber 14 as a water treatment chamber therein, which is designed in principle as usual and known. A conventional rinsing arm 16 is indicated at the top of the rinsing chamber 14, it also being possible for more rinsing arms to be provided in it, of course, especially in the lower region. It is supplied by means of a water line 38 shown in dashed lines. Below, the washing chamber 14 has a floor 17, which is centered in a large depression 18, which is designed like a funnel and forms a sump 19 with a previously described process. In this case, the depression 18 can also be partially covered by a grid, for example as a filter. The walls of the washing chamber 14 and the floor 17 are usually made of metal or stainless steel. The recess 18 in turn can be made of plastic, alternatively also of metal.

At the bottom of the depression 18, a pump 22 according to the invention is arranged as an impeller pump and connected to it in a known manner in a water-conducting manner. A connection of the pump 22 to the recess 18 advantageously has a seal, not shown. An attachment between the two parts recess 18 and pump 22 can be done arbitrarily.

According to 2 the pump 22 has a pump housing 23 with a pump inlet 24 and a pump outlet 25 of a circumferential pump chamber 26 that can be seen clearly in section , it has an angle of about 90° to the longitudinal axis of the pump. It can be connected to the aforesaid water line 38 directly or by means of valves.

In the 2 It can also be seen how a pump chamber 26 is formed in the pump housing 23 . The pump chamber 26 is formed at the top by an upper pump part 28, in which the pump inlet 24 is formed centrally, and at the bottom by a lower pump part 29, from which the pump outlet 25 branches off to the left at the bottom. To the outside, the pump chamber 26 is delimited by the pump outer wall 33, which is advantageously designed as a heating device as described above. For this purpose, it can have a round-cylindrical metal tube and heating conductors thereon on the outside, advantageously thick-film heating conductors. The metallic pump outer wall 33 is sealed along the upper edge and along the lower edge by means of suitable seals on the pump upper part 28 and on the pump lower part 29 and is held in place by pressing them together. For this compression, a latching arm 34 is shown on the right, which is formed in one piece on the upper pump part 28 and is latched via a corresponding latching projection on the lower pump part 29 . Two to six such locking arms 34 can be distributed in the direction of rotation.

The design of the pump shell 28 is relatively simple from the 2 can be seen, where it also has the locking arms 34 mentioned. The design of the lower part 29 of the pump is somewhat more complex; a middle region which is drawn downwards and forms a receiving recess 30 is provided here. In the middle along the dot-dash longitudinal axis of the pump 22 there is a bearing mount 32 which goes further down. Radial outside of the receiving recess 30 there is a circumferential receiving bulge 30′ going upwards, so to speak. This receiving bulge 30' is angled radially outwards by approximately 90° and then again runs approximately parallel to the longitudinal axis of the pump up to a type of pump chamber floor. This pump chamber floor then merges into the pump outlet 25, as is also known from the pumps according to the prior art mentioned at the outset. A guide vane 63 is shown on the wall pointing radially outwards, which vane is formed circumferentially and with a known pitch.

A drive rotor 35 is rotatably mounted essentially within the receiving recess 30 . The drive rotor 35 has a ring-like arrangement of ferromagnetic material 36 which is arranged in a rotor housing 37 or surrounded by it. In the lower area or at the lowest area, the drive rotor 35 has a radial bearing 39 which is pressed in, for example. The radial bearing 39 can advantageously consist of sintered metal or ceramic.

According to a possibility mentioned at the outset, the drive rotor 35 can have a separate ring made of ferromagnetic material 36, which is either inserted or injected into a rotor housing 37 made of plastic. The rotor housing 37 can also consist of at least two parts which enclose the ferromagnetic material 36 and are glued or welded together. The radial bearing 39 can be pressed in and optionally also glued or welded.

In an alternative embodiment of the invention, the ferromagnetic material 36 in the form of granules or powder can be mixed with plastic and then the drive rotor 35 can be cast or injection-molded in one piece, so to speak. The radial bearing 39 can be injected at the same time.

A bearing shaft 41 is inserted into the bearing receptacle 32 and fastened therein, preferably by means of a press fit or press fit. Alternatively, the bearing shaft 41 can also be injected into the lower pump part 29 or into the bearing mount 32 . The bearing shaft 41 can be made of metal or stainless steel, alternatively it can also be made of a suitable stable plastic, for example a fiber-reinforced plastic. It therefore forms a fixed bearing shaft on which the drive rotor 35 is rotatably mounted by means of the radial bearing 39 .

A revolving drive stator 43 is arranged in the receiving bulge 30', which surrounds the receiving recess 30 and thus also the drive rotor 35 in the radial direction. The drive stator 43 has a stator winding 45 which runs around or is arranged radially on the outside, and a stator lamination packet 46 is arranged at a small distance therefrom in the radially inner direction. This is used in a known manner to guide the magnetic field as desired. The drive stator 43 can either be designed as an independent structural unit and then be fastened in the receiving bulge 30', for example glued or snapped in place. Alternatively, as shown here, it can be permanently and stably cast in as a structural unit or stator winding 45 on the one hand and laminated stator core 46 on the other by means of casting resin 47 . Electrical connections to the stator winding 45 are not shown here, but are easy to imagine and implement.

An impeller 50 is provided above the drive rotor 35 and is designed in a manner known per se. The impeller 50 has a lower cover plate 52, which has a central elevation 53 that extends far upwards. A bearing tip 55 mentioned at the outset is arranged on the elevation 53 as an axial bearing or as part of an axial bearing. The bearing tip can be designed and fastened in the manner mentioned at the outset, for example it can be a part made of metal or ceramic that is glued on or injection-molded on.

An upper cover plate 57 runs above the lower cover plate 52, and impeller blades 58 are indicated in between. The impeller 50 can either be produced in a manner known per se from two parts, namely essentially from the lower cover disk 52 and from the upper cover disk 57. The impeller blades 58 can be arranged on one of these cover disks or can be produced in one piece and in one piece with it. Then the two parts of the impeller are connected to one another, for example glued or welded. Alternatively, an impeller can also be made in one piece, as can be seen from FIG DE 102012209832 B3 is known. Then, however, the bearing tip 55, for example, must be attached later.

The impeller 50 can be connected to the drive rotor 35 in various ways. The upper end of the bearing shaft 41 also protrudes into the impeller 50 from below, although there should be a radial distance here so that the bearing shaft 41 does not bear against or rub against the impeller 50 in the radial direction, at least during pumping operation or in normal operation. It can be seen that there is a small distance between the uppermost end of the bearing shaft 41 and the bottom surface of the impeller 50 opposite it, for example a few millimeters. This has been explained at the beginning. This distance serves to ensure that the structural unit made up of the drive rotor 35 and the impeller 50 can be moved somewhat downwards in the longitudinal direction of the pump. The upper end of the bearing shaft 41 should strike the inside of the impeller 50 in the axial direction before the lowermost region of the drive rotor 35 or its rotor housing 37 rests against the receiving recess 30 . Alternatively, the impeller 50 can also be mounted with a further radial bearing at the upper end of the bearing shaft 41 .

The axial bearing mentioned at the outset is formed by the bearing tip 55 on the impeller 50 . A counter-thrust bearing 61 is arranged on a bearing holder 60 which is provided inside the pump inlet 24 , specifically there where the pump inlet 24 virtually opens into the pump chamber 26 . The bearing holder 60 can be held in a manner known per se with two to four radial struts. The counter-thrust bearing 61 can be glued to the bearing holder 60, alternatively it can be molded or injected. It advantageously consists of a suitable bearing material, for example ceramic or sintered metal, possibly also of a plastic such as Delrin or the like.

From the 2 it can be seen that the drive rotor 35 and thus a pump drive is designed as a wet rotor. Water can run down to the receiving recess 30 within the pump chamber 26 between the drive rotor 35 and the lower pump part 29 . In this way, the drive rotor 35 can be water-cooled. Furthermore, there are no problems with a complex seal.

The drive stator 43, in particular the stator winding 45, can also be well cooled by water circulating in the pump chamber 26 due to the special arrangement within the receiving bulge 30'. Cooling is possible in the upper area of the receiving bulge 30', which runs approximately in the radial direction. A relatively direct cooling of the stator winding 45 is also possible on the side pointing radially outwards, where water is present in the region of the guide vanes 63 . Water is also present on the radially inward-pointing side of the receiving bulge 30 ′, ie toward the drive rotor 35 , and can thus also cool the laminated stator core 46 or, via this, the stator winding 45 .

Furthermore, from the 2 it can be seen that the pump 22 is relatively short in the axial longitudinal direction due to a high degree of axial integration.

An alternative embodiment for a pump 22 is in 3 shown. A pump housing 23 with the illustrated upper pump part 28 and lower pump part 29, in particular with the receiving recess 30, is corresponding 2 educated. This also applies to a bearing mount 32 including a bearing shaft 41 fixedly arranged therein. The assembly of drive rotor 135 and impeller 150 is designed differently here. The ferromagnetic material 136 for the drive rotor 135 is designed in the form of a ring, but not with a rectangular cross section, but towards the middle slightly raised at the top. This ferromagnetic material 36 is encapsulated with a rotor housing 137 which at the same time forms a lower cover plate 152 for the impeller 150 . The central elevation 153 is also formed directly on it. A Radial bearing 139 can in turn be injected directly, alternatively subsequently by clamping or the like. be attached.

An upper cover disk 157 of the impeller 150 is manufactured separately and is connected to it, for example glued. Impeller blades 158 can in turn be formed on one of the two parts; this is advantageously recommended on the upper cover plate 157.

Alternatively, a separate rotor housing 137 could be dispensed with entirely, and the entire drive rotor, possibly except for an upper cover disk of the impeller and/or the impeller blades, be produced by injection molding from a plastic to which a high proportion of ferromagnetic material is admixed.

Claims (16)

Pump for a water-bearing household appliance, the pump being an impeller pump with an impeller and having: - a pump housing, the pump housing being made up of at least three parts, namely the upper part of the pump, the lower part of the pump and the outer wall of the pump, - a pump chamber in the pump housing, the pump chamber being formed by the upper part of the pump, the lower part of the pump and the outer wall of the pump, - a pump inlet into the pump housing and a pump outlet from the pump housing, - a heating device, the heating device being formed on the outer wall of the pump or forming the outer wall of the pump, - A pump drive with a drive rotor and a drive stator and a bearing shaft, wherein - the drive stator has a stator winding, - the pump drive is a wet rotor, characterized in that : - the bearing shaft is arranged firmly and immovably on the pump housing, - the drive rotor is rotatably arranged on the bearing shaft, - the impeller is firmly connected to the drive rotor, - the stator winding is arranged on an area of the lower part of the pump which on its other side borders the pump chamber outwards in the radial direction in such a way that essentially only one wall of the lower part of the pump runs between the pump chamber and the stator winding, - the stator winding is surrounded by the pump chamber like a ring. Pump according to Claim 1, characterized in that the drive stator has a stator winding which runs radially on the outside and means for guiding the magnetic field which are arranged radially inside it and are in particular designed as a laminated stator core. A pump according to claim 1 or 2, characterized in that the drive stator is arranged radially between the drive rotor radially inside thereof and the pump chamber radially outside thereof. Pump according to one of the preceding claims, characterized in that the pump chamber runs on the outside along at least 70% of the axial length of the drive stator, in particular along at least 90% of the axial length. Pump according to one of the preceding claims, characterized in that the pump inlet is formed on the upper part of the pump, the pump outlet being formed on the lower part of the pump and viewed in the axial length of the pump is arranged below the impeller, preferably viewed in the axial length of the pump not completely below the drive stator . Pump according to one of the preceding claims, characterized in that the pump outer wall is a pipe section, preferably round-cylindrical, with the pipe section in particular being cut straight at both ends and at right angles to its axial length, heating conductors being arranged on its outside to form the heating device, the are designed as thin-film or thick-film heating devices. Pump according to one of the preceding claims, characterized in that the bearing shaft is fixedly arranged on the lower part of the pump, with the drive rotor preferably being rotatably mounted on the bearing shaft by means of a radial bearing in the lower region of the drive rotor and in the axial direction by means of an axial bearing at the upper end of the impeller on the upper part of the pump Direction is mounted, the axial bearing for the drive rotor preferably being arranged at a central point on the uppermost area or on the area of the drive rotor which is closest to the pump inlet and is arranged as an extension of the bearing shaft, with a counter-axial bearing for the axial bearing is arranged on the pump housing or on the upper part of the pump, in particular close to or in the pump inlet. Pump according to Claim 7, characterized in that the axial bearing consists of a different material and is attached to the impeller, preferably glued or injected, the axial bearing in particular having a convex tip on the impeller made of plastic, ceramic or sintered metal. Pump according to Claim 7 or 8, characterized in that in the state when the impeller is at a maximum distance from the pump inlet along a longitudinal direction of a longitudinal center axis, a distance of at most 5 mm is provided between the axial bearing on the impeller and the counter-axial bearing, preferably in In this state, a free end or an end surface of the bearing shaft rests against an end or an inner end surface of a receiving opening on the impeller for the bearing shaft, with preferably in this state the underside of the drive rotor not resting on the upper side of the pump lower part, but rather a distance between 1 mm and 10mm. Pump according to one of the preceding claims, characterized in that the ferromagnetic material or the rotor laminated core of the drive rotor is surrounded by a rotor housing and does not come into contact with water in the pump chamber, the rotor housing preferably being firmly connected to the impeller to form a structural unit, wherein the rotor housing is formed in one piece with at least part of the impeller, in particular at least partially forming a lower part of the impeller, preferably together with an internally raised area of the impeller, at the highest point of which the axial bearing of the impeller is formed according to one of claims 7 to 9. Pump according to Claim 10, characterized in that an upper part of the impeller is designed as a separate plastic part and is fastened to the lower part of the impeller, in particular is permanently fastened, preferably fastened by gluing, welding, ultrasonic welding or friction welding. Pump according to one of Claims 1 to 10, characterized in that the impeller is produced using a single-component injection molding process or using a multi-component injection molding process, in particular in one piece, and is connected as a finished part to the drive rotor to form a structural unit. Pump according to one of the preceding claims, characterized in that the ferromagnetic material of the drive rotor is mixed with a plastic and the entire drive rotor is produced in a casting process, in particular in a plastic injection molding process, with preferably at least part of the impeller according to claim 11 or 12 in the same Step with is manufactured, in particular the lower part of the impeller. Pump according to one of the preceding claims, characterized in that a pump outlet is provided in a region which is furthest away from the pump inlet, viewed in the longitudinal direction of the pump. Pump according to one of the preceding claims, characterized in that it is designed to be installed vertically or to be installed with the bearing shaft running vertically. Water-bearing household appliance with a pump according to one of the preceding claims, characterized in that the pump is installed with a vertical bearing shaft, the pump inlet pointing upwards or being arranged above, the pump outlet preferably forming the lowest point of the pump chamber.

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