Pump for a water-carrying household appliance and water-carrying household appliance with such a pump

Description

Area of ​​application and state of the art

[0001] The invention relates to a pump for a water-conducting household appliance and to a water-conducting household appliance with such a pump, wherein the pump is an impeller pump.

[0002] Such an impeller pump for a dishwasher, a water-conducting household appliance, is known from WO 2014 / 198427 A1. The pump or 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 thus partially surrounded by water from the pump chamber or comes into contact with it. Furthermore, the drive rotor comprises ferromagnetic material. A drive stator with a corresponding stator winding runs radially outside the drive rotor.

[0003] DE 10 2019 206 203 A1 discloses a pump and a water-conducting household appliance equipped with it, comprising a pump housing including a pump chamber, a heating device, and a pump drive. A drive stator of the pump drive, which is designed as a wet rotor, has a stator winding surrounded by a ring-like pump chamber. Figure 4 therein shows how a ring-like region of the pump chamber is arranged radially outside the stator winding.

[0004] EP 2 862 494 A1 also discloses a pump for a water-conducting household appliance, including such a water-conducting household appliance, in which a pump chamber surrounds the stator in a ring-like manner.

[0005] From DE 10 2012 216 196 A1 an impeller pump is generally known, in which, however, the pump chamber is considerably far away from a drive stator in the axial direction.

[0006] From US 2017 / 302133 A1, yet another impeller pump is known in which, as in US 2006 / 251513 A1, a pump chamber is arranged axially away from a drive stator. Task and solution

[0007] The invention is based on the object of creating a pump as mentioned above 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.

[0008] This object is achieved by a pump having the features of claim 1 and by a water-conducting household appliance having the features of claim 16. Advantageous and preferred embodiments of the invention are the subject of the further claims and are explained in more detail below. Some of the features are described only for the pump or only for the water-conducting household appliance. However, they are intended to be able to apply independently and independently of one another to both such a pump and such a water-conducting household appliance. The wording of the claims is incorporated into the content of the description by express reference.

[0009] 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 an upper pump part, a lower pump part and a pump outer wall. The pump chamber itself is formed by the upper pump part and the lower pump part as well as the pump outer wall, and is therefore partially formed directly by the pump housing. Advantageously, the pump housing has numerous other parts, or some of the parts mentioned, in particular the upper pump part and lower pump part, go beyond this in terms of function and design and serve even more functions than those required for the pump chamber. The pump outer wall is advantageously only the circumferential 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, wherein the pump inlet advantageously runs directly into the pump chamber. The pump outlet advantageously runs out of the pump chamber. Due to the design as an impeller pump, the pump inlet at least into the pump chamber is in the axial direction of the pump. The pump outlet at least out of the pump chamber runs at an angle to this, advantageously between 60° and 120°, particularly advantageously almost or completely tangentially or as an outwardly 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, in a conventional manner, has a drive rotor and a drive stator. A bearing shaft is also provided which runs along the axial longitudinal axis of the pump.The drive stator has a stator winding, so there's no electrical contact with the drive rotor. The entire pump drive is designed as a wet rotor, so the drive rotor essentially runs in the water or is at least partially surrounded by water, and is thus connected to the pump chamber via a water-conducting connection, or is located in the pump chamber.

[0010] According to the invention, the bearing shaft is fixedly and immovably mounted on the pump housing; detailed possibilities are explained in more detail below. The drive rotor is rotatably mounted on the bearing shaft, advantageously by means of suitable bearings. The drive rotor can be arranged or run on a base or just above a base of the pump base. The impeller is fixedly connected to the drive rotor and thus also rotatably mounted on the rotating shaft. Furthermore, the fixed connection makes it immovable relative to the drive rotor. It can be at least partially designed or manufactured together with the latter, which will be explained in more detail below.

[0011] Furthermore, the stator winding is arranged in an area of ​​the pump base which borders the pump chamber radially outwards, i.e. on its other side, in such a way that only one wall of the pump base runs between the pump chamber in this area and the stator winding, or only one or a single wall of the pump base runs here, and in particular no other components are located between the pump chamber and the stator winding in this area. The pump chamber is therefore pulled so far downwards in the axial direction of the pump, or the drive stator is shifted so far upwards towards the impeller, that the drive stator and its stator winding are also surrounded by the pump chamber in the radial direction. This enables good cooling of the stator winding by the water in the pump chamber. Furthermore, a compact design in the axial direction can be achieved.The stator winding is thus surrounded by the pump chamber in a ring-like manner. It is important to ensure that the drive stator is sealed from the pump chamber.

[0012] Thus, the invention can create a pump that enables advantageous cooling of the drive stator or its stator winding. Cooling of the drive rotor can be advantageously achieved by designing it as a wet rotor, which is thus already well cooled. The axially compact design allows for a relatively short pump length and thus an advantageous arrangement in the household appliance without consuming unnecessary space.

[0013] In an advantageous embodiment of the invention, the drive stator has a stator winding running radially outwards and means for guiding the magnetic field radially inside thereof. These means for guiding the magnetic field are advantageously designed as a stator laminated core, as is known per se. This design has the advantage that the magnetic field towards the drive rotor arranged radially inside the stator and surrounded by the drive stator can be designed as well as possible or can be designed as desired. Furthermore, the stator winding running radially outwards is thus located as close as possible to the pump chamber surrounding it and can therefore be cooled as well as possible by the water circulating therein. For example, it is possible to insert or mount the drive stator in a corresponding recess in the pump housing or the lower part of the pump.In the direction away from the pump's upper section, this can be open, allowing for the best and simplest electrical connection to the stator winding. Therefore, the drive stator is preferably located, viewed in the radial direction, between the drive rotor, which is located radially inside it, and the pump chamber or a part or section of the pump chamber that is located radially outside it. In particular, the area of ​​the pump chamber that merges entirely or at least partially into the pump outlet lies radially outside the drive stator.

[0014] While the drive stator has the aforementioned means for guiding the magnetic field in addition to the stator winding, the drive rotor can have ferromagnetic material or a rotor laminated core. Advantageously, the drive rotor has ferromagnetic material that can, for example, be embedded in plastic or surrounded by plastic walls. This can be a so-called rotor housing, so that this ferromagnetic material or rotor laminated core cannot come into contact with water. Alternatively, a finished ferromagnetic material, for example in ring form or partially ring form, can be over-molded with plastic or inserted into prefabricated plastic parts, for example in shell form, and glued. As yet another alternative, the ferromagnetic material of the drive rotor can be admixed with a plastic or mixed with plastic. In this way, the entire drive rotor can be manufactured in a casting process orPlastic injection molding can be used. It may also be possible to manufacture at least part of the impeller in the same step, particularly a lower cover plate, which will be explained below.

[0015] In a possible embodiment of the invention, the pump chamber does not extend completely outside the axial length of the drive stator, but only partially. However, it should advantageously extend along at least 70% of its axial length, in particular along at least 90%. This allows the water in the pump chamber to provide the best possible cooling of the drive stator or its stator winding. However, the pump chamber does not have to extend completely outside the drive stator or its stator winding.

[0016] In a further advantageous embodiment of the invention, an upper side or an upper end face of the drive stator or 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 pump base. This allows cooling by the water in the pump chamber, so that the drive stator can even be cooled on two sides.

[0017] Advantageously, 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 at least partially tubular or designed like 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 formed by it. The pump outlet, in turn, can be formed independently of this on the lower part of the pump and, viewed in the axial length of the pump, can be arranged at least below the impeller. The pump outlet can be located 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 be located completely below the drive stator, which in turn can limit the overall axial length of the pump.

[0018] The outer wall of the pump is advantageously tubular, particularly cylindrical or round-cylindrical. The tubular section can be cut straight at both ends and at right angles to its axial length. Advantageously, the outer wall of the pump also runs concentrically with the longitudinal center axis of the pump and the bearing shaft.

[0019] Heating conductors can be arranged on an outer side of the pump's outer wall to form the heating device. These heating conductors can be designed as thin-film or thick-film heating devices, or alternatively as other heating means such as tubular heaters. This makes it possible for the heating conductors to be separated from the water in the pump chamber by the pump's outer wall. A thin pump outer wall, for example, 0.1 mm to 3 mm, enables very good heat transfer into the water in the pump chamber. For example, the pump's outer wall can be made of metal, for example as a metal tube, and the aforementioned heating conductors can be printed as thin-film or thick-film heating devices. For this purpose, reference is made, for example, to the aforementioned WO 2014 / 198427 A1 and DE 10 2011 003 464 A1.

[0020] In one embodiment of the invention, the bearing shaft is firmly mounted on the pump base 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 pump base, preferably a sturdy fiber-reinforced plastic. This can also reduce corrosion problems.

[0021] The drive rotor, which rotates relative to the bearing shaft, is advantageously mounted on it by means of a radial bearing in its lower section. Another radial bearing can be provided in the upper section of the drive rotor, possibly also on an impeller arranged above it, which is firmly connected to it. However, this is not absolutely necessary, especially not if an axial bearing at the upper end of the impeller also provides a certain degree of radial support. In any case, the arrangement of the axial bearing at the top of the impeller has the advantage that it can easily rest against a counter-axial bearing. This is mounted in the pump inlet, advantageously by means of radially extending webs. Although the counter-axial bearing and axial bearing are thus located in the incoming water flow, this can also provide cooling and possibly lubrication, while other locations are considerably more complex.Furthermore, a special bearing shaft is not required; it can be a simple, straight design. This makes it possible to limit the number of bearings to two in total: the radial bearing and the axial bearing.

[0022] A radial bearing can be made of plastic, a suitable ceramic, or a sintered material. It can be clamped or glued to the drive rotor, or alternatively, it can be injection-molded. To keep it simple, it should be designed so that it does not have to, or cannot, absorb any axial forces. Sealed rolling bearings, particularly ball bearings or needle bearings, may also be used, which typically have even lower friction. However, these should be well sealed.

[0023] The thrust bearing is preferably made of a different material than the impeller on which it is mounted. It can be manufactured separately and mounted on the impeller or the drive rotor. It may also be molded onto the impeller, for example, using a two-component injection molding process.

[0024] In general, the axial 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-axial bearing is also similarly curved, radial centering can be enabled in addition to the axial support. Since the axial bearing is arranged at the point on the rotating part that is furthest away or highest, the best possible force ratio is achieved for both the axial bearing and the radial bearing for a desired, defined support of the assembly consisting of the drive rotor and impeller. Alternatively, it is also conceivable to curve the axial bearing on the impeller and the counter-axial bearing in opposite directions, which also allows for radial bearings as centering in addition to an axial support.A thrust bearing, and possibly also the counter thrust bearing, can be made of graphite-containing plastic or be formed from graphite-containing plastic. It can be injection-molded or molded onto both the impeller and the pump head, and may also be subsequently attached, for example, by gluing and / or clamping.

[0025] In an alternative design, an axial bearing for the drive rotor can be provided on its radial bearing. This would require only a single bearing, although this would require a significantly more complex design.

[0026] The assembly comprising the drive rotor and impeller can be designed to have a certain travel in the axial direction of the pump, for example 0.1 mm to 10 mm, advantageously 0.5 mm to 5 mm. When the pump is in operation, the impeller is usually pulled axially towards the pump inlet due to its pumping function, so that the previously described axial bearing is sufficient to support it axially there during use. Therefore, when the drive rotor / impeller is at a standstill, there can even be a gap between the axial bearing and the counter-axial bearing, advantageously in the aforementioned range, particularly advantageously between 0.5 mm and 3 mm. This also makes it possible for the two aforementioned bearings, namely the axial bearing and the radial bearing, to be sufficient.

[0027] 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 rests against one end or an inner end surface of a receiving opening on the impeller into which the bearing shaft is inserted. This ensures that the underside of the drive rotor never rests against the top of the pump base, but rather a gap is provided between it. This gap can be between 1 mm and 10 mm, for example. This ensures that the drive rotor can still rotate when the pump is dry, and that bearing support and therefore friction only occurs between the end of the bearing shaft and the inner end surface of the impeller. This can be easily absorbed, for example through structural design or appropriate choice of material.In any case, this prevents the underside of the drive rotor from rubbing or scratching against the pump base. Dry running of the pump cannot realistically be prevented, but it can at least prevent any damage that might result from it.

[0028] In a further embodiment of the invention, a structural unit comprising the impeller and drive rotor can be formed at least partially as a single piece, such that at least a 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 comprise not only a type of lower impeller cover disk, but also a region of the impeller that is usually raised radially inward. This raised radially inward region can form or have the aforementioned axial bearing at its highest point.

[0029] In an advantageous embodiment, an upper part of the impeller can then be formed as a separate part, preferably made of plastic, and attached to the lower part of the impeller. Attachment should be permanent; possible methods include gluing, welding, ultrasonic welding, or friction welding. This upper part of the impeller advantageously also includes the impeller blades, at least partially, or advantageously entirely. This allows for a simple mold and thus also a simple manufacturing process for the lower part of the impeller, including the drive rotor or rotor housing.

[0030] Alternatively, the impeller can be manufactured separately from the drive rotor, for example, using a single-component or multi-component injection molding process. The impeller can advantageously be manufactured in one piece, or alternatively in two parts with a lower and upper part, with the impeller blades molded onto one of the two parts. The impeller is then joined to the drive rotor to form a single unit, for example, by gluing or welding in one of the aforementioned ways.

[0031] In a preferred embodiment of the invention, the pump outlet can be provided in a region of the pump or pump chamber that is furthest from the pump inlet, viewed in the longitudinal direction of the pump. This can advantageously also be the deepest part of the pump chamber, so that, in a possible vertical arrangement of the pump, water drains automatically from the pump chamber, at least if a drain or the like is not closed by a valve or the like. This can reduce hygiene problems within the pump or pump chamber.

[0032] In a further possible advantageous embodiment of the invention, the pump inlet can be designed, in addition to a possible aforementioned tubular shape, to be increasingly widened upwards or in the direction away from the impeller or the pump chamber. A kind of flat, wide funnel can be formed here. This widening advantageously takes place to a diameter even larger than the pump chamber. This allows a sump for a dishwasher or washing machine to 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.

[0033] Preferably, at least one guide vane can be provided on the pump base, which extends into the pump chamber. Such a guide vane is advantageously provided on a wall that runs radially outward and optionally along the drive stator, advantageously extending in the axial direction. Particularly preferably, such a guide vane is manufactured as a single piece with the pump base. It can have a downward slope in the direction of circulation of the pumped water or toward the pump outlet and serve to control the water flow within the pump chamber.

[0034] In a possible further development of the invention, locking devices can be provided on the pump or on the pump housing to hold them together. Advantageously, the locking devices are formed as a single piece and extend equally, either from the upper part of the pump to the lower part of the pump or vice versa. Thus, the locking devices can be connected or formed as a single piece to one of the two parts of the pump housing at one end. The other free end is locked onto the other part. This eliminates the need for separate means to hold the pump housing together.

[0035] In a preferred embodiment of the invention, the pump is installed vertically in a water-conducting household appliance, so that the bearing shaft runs vertically. It is advantageous for the pump inlet to point upwards or be arranged at the top, thus forming the highest part of the pump. The pump outlet then forms, as previously described, the lowest point of the pump chamber, for example, for advantageous, largely automatic emptying of the pump chamber. The pump is preferably arranged directly beneath a treatment chamber of the water-conducting household appliance, particularly when installed in a dishwasher, so that no intermediate valves or the like are necessary.

[0036] These and other features emerge not only from the claims but also from the description and the drawings. The individual features may be implemented individually or in combination in an embodiment of the invention and in other fields, and may represent advantageous and individually protectable embodiments for which protection is claimed here. The division of the application into subheadings and individual sections does not limit the generality of the statements made therein. Brief description of the drawings

[0037] Embodiments of the invention are illustrated in the drawings and explained in more detail below. In the drawings: Fig. 1 is a schematic view of a dishwasher as a household appliance according to the invention with a pump according to the invention, Fig. 2 is a section through the pump according to the invention and Fig. 3 is an enlarged section through a modified impeller for the pump according to the invention. Detailed description of the implementation examples

[0038] In the Fig. 11 shows a schematic diagram of a dishwasher 11 as a household appliance according to the invention, comprising a housing 12 and a washing chamber 14 as a water treatment chamber therein, which washing chamber is essentially designed in a conventional and known manner. At the top of the washing chamber 14, a conventional washing arm 16 is indicated, although more washing arms can of course also be provided therein, particularly in the lower area. It is supplied by a water line 38 shown in dashed lines. At the bottom, the washing chamber 14 has a floor 17 which merges centrally into a large recess 18 which is funnel-shaped and forms a sump 19 with a drain as described above. The recess 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, or alternatively, of metal.

[0039] At the bottom of the recess 18, a pump 22 according to the invention is arranged as an impeller pump and is connected to it in a known manner for conducting water. The connection of the pump 22 to the recess 18 advantageously includes a seal (not shown). Any fastening between the two parts, recess 18 and pump 22, can be implemented.

[0040] According to Fig. 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, clearly visible in cross-section. The pump inlet 24 is a short pipe socket along the longitudinal axis of the pump 22, shown in dash-dotted lines. The pump outlet 25 protrudes laterally and approximately tangentially, forming an angle of approximately 90° to the longitudinal axis of the pump. It can be connected to the aforementioned water line 38 directly or via valves.

[0041] In the Fig. 2It 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 the center of which the pump inlet 24 is formed, and at the bottom by a lower pump part 29, from which the pump outlet 25 branches off to the bottom left. The pump chamber 26 is delimited on the outside by the pump outer wall 33, which is advantageously designed as the heating device described above. For this purpose, it can have a round-cylindrical metal tube and heating conductors 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 upper pump part 28 and the lower pump part 29 and is held in place by pressing them together.For this compression, a locking arm 34 is shown on the right, which is formed integrally on the pump upper part 28 and which is locked into place via a corresponding locking projection on the pump lower part 29. Two to six such locking arms 34 can be provided distributed in the direction of rotation.

[0042] The design of the pump upper part 28 is relatively simple from the Fig. 2can be seen, whereby it also has the aforementioned locking arms 34. The design of the pump base 29 is somewhat more complex; here, a downwardly drawn central region is provided, which forms a receiving recess 30. In the middle, along the dash-dotted longitudinal axis of the pump 22, a bearing recess 32 is formed which extends even further downwards. Radially outside the receiving recess 30, a circumferential receiving bulge 30' is provided, so to speak, extending upwards. This receiving bulge 30' is angled radially outwards by approximately 90° and then 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 beginning. On the radially outward-facing wall, a guide vane 63 is shown, which is formed circumferentially and with a known pitch.

[0043] 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 or surrounded by a rotor housing 37. In the lower region, or at the lowest region, the drive rotor 35 has a radial bearing 39, which is, for example, pressed in. The radial bearing 39 can advantageously be made of sintered metal or ceramic.

[0044] According to one possibility mentioned above, the drive rotor 35 can have a separate ring made of ferromagnetic material 36, which is either inserted or injected into a plastic rotor housing 37. The rotor housing 37 can also consist of at least two parts that enclose the ferromagnetic material 36 and are glued or welded together. The radial bearing 39 can be pressed in and, if necessary, also glued or welded.

[0045] In an alternative embodiment of the invention, the ferromagnetic material 36 can be mixed with plastic in granular or powder form, and then the drive rotor 35 can be cast or injection-molded as a single piece. The radial bearing 39 can also be injection-molded.

[0046] A bearing shaft 41 is inserted into the bearing mount 32 and secured therein, preferably by a press fit or clamp fit. Alternatively, the bearing shaft 41 can also be injection-molded into the pump base 29 or into the bearing mount 32. The bearing shaft 41 can be made of metal or stainless steel, or alternatively, it can be made of a suitable sturdy plastic, such as a fiber-reinforced plastic. It thus forms a fixed bearing shaft on which the drive rotor 35 is rotatably mounted by means of the radial bearing 39.

[0047] A rotating drive stator 43 is arranged in the receiving recess 30', which radially surrounds the receiving recess 30 and thus also the drive rotor 35. The drive stator 43 has a stator winding 45 arranged or arranged radially outward, and a stator laminated core 46 is arranged at a short distance therefrom in the radial inner direction. This serves in a known manner to guide the magnetic field as desired. The drive stator 43 can either be designed as a separate structural unit and then fastened in the receiving recess 30', for example, by gluing or locking it in place. Alternatively, as shown here, it can be permanently and stably cast as a structural unit, or the stator winding 45 on the one hand and the stator laminated core 46 on the other hand can be permanently and stably cast in place using cast resin 47. Electrical connections to the stator winding 45 are not shown here, but are easily conceivable and implementable.

[0048] Above the drive rotor 35, an impeller 50 is provided, which is designed in a known manner. The impeller 50 has a lower cover disk 52, which has a centrally located raised portion 53 projecting upwards. A bearing tip 55, as mentioned above, is arranged on the raised portion 53 as an axial bearing or as part of an axial bearing. The bearing tip can be designed and secured in the manner mentioned above; for example, it can be a glued or molded-on part made of metal or ceramic.

[0049] An upper cover plate 57 extends above the lower cover plate 52, and impeller blades 58 are indicated between them. The impeller 50 can be manufactured in a conventional manner from two parts, namely essentially from a lower cover plate 52 and an upper cover plate 57. The impeller blades 58 can be arranged on one of these cover plates or can be manufactured as a single piece therewith. The two parts of the impeller are then connected to one another, for example, by gluing or welding. Alternatively, an impeller can also be manufactured as a single piece, as is known from DE 102012209832 B3. In this case, however, the bearing tip 55, for example, must be subsequently attached.

[0050] The impeller 50 can be connected to the drive rotor 35 in various ways. The upper end of the bearing shaft 41 also projects into the impeller 50 from below, but there should be a radial clearance here so that, at least during pumping or normal operation, the bearing shaft 41 does not radially contact or rub against the impeller 50. It can be seen that a small clearance, for example a few millimeters, is provided between the uppermost end of the bearing shaft 41 and the opposite bottom surface of the impeller 50. This was explained at the beginning. This clearance serves to enable the assembly consisting of the drive rotor 35 and impeller 50 to be moved slightly downward in the longitudinal direction of the pump. The upper end of the bearing shaft 41 should abut the inside of the impeller 50 in the axial direction before the lowermost area of ​​the drive rotor 35 or its rotor housing 37 comes into contact with the receiving recess 30.Alternatively, the impeller 50 can also be mounted with another radial bearing at the upper end of the bearing shaft 41.

[0051] The aforementioned axial bearing is formed by the bearing tip 55 on the impeller 50. A counter-axial bearing 61 is arranged on a bearing holder 60, which is provided within the pump inlet 24, specifically where the pump inlet 24 essentially opens into the pump chamber 26. The bearing holder 60 can be held in place in a conventional manner with two to four radial struts. The counter-axial bearing 61 can be glued to the bearing holder 60, or alternatively, it can be molded or injected. It is advantageously made of a suitable bearing material, for example, ceramic or sintered metal, or possibly also a plastic such as Delrin or the like.

[0052] From the Fig. 2It can be seen that the drive rotor 35, and thus the pump drive, is designed as a wet rotor. Water can flow downwards within the pump chamber 26 between the drive rotor 35 and the pump base 29 toward the receiving recess 30. This allows the drive rotor 35 to be water-cooled. Furthermore, there are no problems with complex sealing.

[0053] The drive stator 43, in particular the stator winding 45, can also be effectively cooled by water circulating in the pump chamber 26 due to the special arrangement within the receiving recess 30'. Cooling is possible in the upper region of the receiving recess 30', which runs approximately in a radial direction. Likewise, relatively direct cooling of the stator winding 45 is possible on the radially outward-facing side, where water is present in the area of ​​the guide vanes 63. Water is also present on the radially inward-facing side of the receiving recess 30', i.e., toward the drive rotor 35, and can thus also cool the stator laminated core 46 and, via this, the stator winding 45.

[0054] Furthermore, the Fig. 2 It can be seen that the pump 22 is relatively short in the axial longitudinal direction due to a high axial integration.

[0055] An alternative design for a pump 22 is shown in the Fig. 3A pump housing 23 with the pump upper part 28 and pump lower part 29 shown, in particular with the receiving recess 30, is correspondingly Fig. 2 This also applies to a bearing mount 32 including the bearing shaft 41 fixedly arranged therein. The assembly comprising the drive rotor 135 and impeller 150 is designed differently here. The ferromagnetic material 136 for the drive rotor 135 is designed in a ring shape, however, not with a rectangular cross-section, but rather slightly drawn upwards towards the center on the upper side. This ferromagnetic material 36 is overmolded with a rotor housing 137, which simultaneously forms a lower cover plate 152 for the impeller 150. The central elevation 153 is also directly molded onto it. A radial bearing 139 can also be directly molded in, or alternatively, subsequently attached by clamping or the like.

[0056] An upper cover plate 157 of the impeller 150 is manufactured separately and is connected to it, for example, by adhesive bonding. Impeller blades 158 can in turn be formed on one of the two parts; this is advantageously recommended on the upper cover plate 157.

[0057] 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, could be manufactured by injection molding from a plastic to which a high proportion of ferromagnetic material is added.

Claims

1. Pump (22) for a water-conducting household appliance (11), the pump (22) being an impeller pump with an impeller (50, 150) and having: - a pump housing (23), the pump housing (23) being made up of at least three parts, namely the pump top (28), the pump lower part (29) and the outer pump wall (33), - a pump chamber (26) in the pump housing (23), the pump chamber (26) being formed by the pump top (28), the pump lower part (29) and the outer pump wall (33), - a pump inlet (24) into the pump housing (23) and a pump outlet (25) out of the pump housing (23), - a heating device, the heating device being formed on the outer pump wall (33) or forming the outer pump wall (33), - a pump drive with a drive rotor (35) and a drive stator (43) as well as a bearing shaft (41), - the drive stator (43) having a stator winding (45), - the pump drive being a wet runner, the stator winding (45) being surrounded in the manner of a ring by the pump chamber (26), the impeller (50, 150) being firmly connected to the drive rotor (35), characterized in that: - the bearing shaft (41) is arranged fixedly and immovably on the pump housing (23), - the drive rotor (35) is rotatably arranged on the bearing shaft (41), - the stator winding (45) is arranged on a region of the pump lower part (29) which, on its other side, adjoins the pump chamber (26) in the radial direction outwards, in such a way that only one wall of the pump lower part (29) extends between the pump chamber (26) and the stator winding (45).

2. Pump according to Claim 1, characterized in that the drive stator (43) has a stator winding (45) running radially on the outside and means for guiding the magnetic field arranged radially inside the latter, in particular designed as a stator laminate stack (46).

3. Pump according to claim 1 or 2, characterized in that the drive stator (43) is arranged in the radial direction between the drive rotor (35) radially inside the latter and the pump chamber (26) radially outside the latter.

4. Pump according to one of the preceding claims, characterized in that the pump chamber (26) extends externally along at least 70% of the axial length of the drive stator (43), in particular along at least 90% of the axial length.

5. Pump according to one of the preceding claims, characterized in that the pump inlet (24) is formed on the pump top (28), the pump outlet (25) being formed on the pump lower part (29) and being arranged below the impeller (50, 150) as viewed in the axial length of the pump (22), preferably not completely below the drive stator (43) when viewed in the axial length of the pump (22).

6. Pump according to one of the preceding claims, characterized in that the outer pump wall (33) is a pipe section, preferably round cylindrical, in particular the pipe section being cut off straight at both ends and at right angles to its axial length, with heating conductors being arranged on its outside to form the heating device, which conductors are designed as a thin-film or thick-film heating device.

7. Pump according to one of the preceding claims, characterized in that the bearing shaft (41) is arranged fixedly on the pump lower part (29), wherein preferably the drive rotor (35) is rotatably mounted on the bearing shaft (41) by means of a radial bearing (39, 139) in the lower region of the drive rotor (35) and is mounted in the axial direction on the upper end of the impeller (50, 150) on the pump top (28) by means of a axial bearing (55, 155), wherein preferably the axial bearing (55, 155) for the drive rotor (35) is arranged at a central point on the uppermost region or on that region of the drive rotor (35) which is closest to the pump inlet (24) and is arranged in the extension of the bearing shaft (41), wherein a counter-axial bearing (61) for the axial bearing (55, 155) is arranged on the pump housing (23) or on the pump top (28), in particular close to or in the pump inlet (24).

8. Pump according to claim 7, characterized in that the axial bearing (55, 155) consists of a different material and is attached to the impeller (50, 150), preferably glued or injectionmoulded to it, wherein in particular the axial bearing (55, 155) has a convex tip on the impeller (50, 150) made of plastic, ceramic or sintered metal.

9. Pump according to claim 7 or 8, characterized in that in the state when the impeller (50, 150) is at a maximum distance from the pump inlet (24) along a longitudinal direction of a longitudinal center axis, a distance of at most 5 mm is provided between the axial bearing (55, 155) on the impeller (50, 150) and the counter-axial bearing (61), wherein preferably in this state a free end or an end surface of the bearing shaft (41) abuts against an end or an inner end surface of a receiving opening at the impeller (50, 150) for the bearing shaft (41), wherein preferably in this state the underside of the drive rotor (35) does not bear against the upper side of the pump lower part (29), but is spaced apart from it by a distance between 1 mm and 10 mm.

10. Pump according to one of the preceding claims, characterized in that the drive rotor (35) comprises ferromagnetic material or a rotor laminate, the ferromagnetic material or the rotor laminations of the drive rotor (35) being surrounded by a rotor housing (37, 137) and not coming into contact with water in the pump chamber (26), preferably the rotor housing (37, 137) being firmly connected to the impeller (50, 150) to form a single unit, wherein the rotor housing (37, 137) is formed in one piece with at least a part of the impeller (50, 150), in particular at least partially forms a lower part of the impeller (50, 150), preferably together with an internally raised region of the impeller (50, 150), at the highest point of which the axial bearing (55, 155) of the impeller (50, 150) is formed according to one of claims 7 to 9.

11. Pump according to claim 10, characterized in that an upper part of the impeller (50, 150) is designed as a separate plastic part of its own and is attached to the lower part of the impeller (50, 150), in particular is attached non-detachably, preferably is attached by adhesive bonding, welding, ultrasonic welding or friction welding.

12. Pump according to one of the claims 1 to 10, characterized in that the impeller (50, 150) is manufactured in a single-component injection moulding process or in a multicomponent injection moulding process, in particular in one piece, and is connected to the drive rotor (35) as a finished part to form a structural unit.

13. Pump according to one of the preceding claims, characterized in that the drive rotor (35) has ferromagnetic material, wherein the ferromagnetic material of the drive rotor (35) is admixed with a plastic and the entire drive rotor (35) is produced in the casting process, in particular in the plastic injection moulding process, wherein preferably at least a part of the impeller (50, 150) according to claim 11 or 12 is produced in the same step, in particular the lower part of the impeller (50, 150).

14. Pump according to one of the preceding claims, characterized in that the pump outlet (25) is provided at a region lying farthest away from the pump inlet (24) as viewed in the longitudinal direction of the pump (22).

15. Pump according to one of the preceding claims, characterized in that it is designed to be installed vertically or to be installed with a vertically extending bearing shaft (41).

16. Water-conducting household appliance (11) comprising a pump (22) according to one of the preceding claims, characterized in that the pump (22) is installed with a vertical bearing shaft (41), the pump inlet (24) pointing upwards or being arranged at the top, with the pump outlet (25) preferably forming the lowest point of the pump chamber (26).