PUMP FOR A WATER-CARRYING HOUSEHOLD APPLIANCE AND WATER-CARRYING HOUSEHOLD APPLIANCE HAVING SUCH A PUMP

Abstract

An impeller pump for a dishwasher has a pump housing comprising a pump upper portion, pump lower portion and pump outer wall in which a pump chamber is arranged. It has a pump inlet into the pump housing and a pump outlet out of the pump housing and a heating device, which forms the pump outer wall, and a pump drive having a drive rotor, a drive stator having a stator winding and a bearing shaft. The bearing shaft is fixedly arranged on the pump housing and the drive rotor is fixedly connected to the drive rotor and they are rotatably arranged on the bearing shaft. The stator winding is arranged on a region of the pump lower portion which adjoins the pump chamber at the other side thereof in an outward radial direction so that between the pump chamber and stator winding only one wall of the pump lower portion extends so that the stator winding is surrounded by the pump chamber in an annular manner. It can thus be effectively cooled by water in the pump chamber.

Claims

1. Pump for a water-carrying household appliance, wherein said pump is an impeller pump having an impeller and having: a pump housing, wherein said pump housing is constructed from at least three components, that is to say, a pump upper portion, a pump lower portion and a pump outer wall, a pump chamber in said pump housing, wherein said pump chamber is formed by said pump upper portion, said pump lower portion and said pump outer wall, a pump inlet into said pump housing and a pump outlet out of said pump housing, a heating device, wherein said heating device is formed on said pump outer wall or forms said pump outer wall, a pump drive having a drive rotor and a drive stator and a bearing shaft, wherein said drive stator has a stator winding, said pump drive is a wet runner, wherein: said bearing shaft is arranged on said pump housing in a fixed and non-movable manner, said drive rotor is rotatably arranged on said bearing shaft, said impeller is fixedly connected to said drive rotor, said stator winding is arranged on a region of said pump lower portion which adjoins said pump chamber at an other side thereof in an outward radial direction so that between said pump chamber and said stator winding substantially only one wall of said pump lower portion extends, said stator winding is surrounded by said pump chamber in an annular manner.

2. Pump according to claim 1, wherein said drive stator has a radially outwardly extending stator winding and means which are arranged radially inside said stator winding for magnetic field conduction.

3. Pump according to claim 1, wherein said drive stator is arranged in a radial direction between said drive rotor and said pump chamber, wherein said drive rotor is radially inside said drive stator and said pump chamber is arranged radially outside it.

4. Pump according to claim 1, wherein said pump chamber extends at an outer side along at least 70% of an axial length of said drive stator.

5. Pump according to claim 1, wherein said pump inlet is formed in said pump upper portion, wherein said pump outlet is formed in said pump lower portion and, when viewed in an axial length of said pump, is arranged below said impeller but not completely below said drive stator.

6. Pump according to claim 1, wherein said pump outer wall is a pipe portion, wherein said pipe portion is cut at both ends in a linear and right-angled manner with respect to an axial length thereof, wherein, on an outer side thereof in order to form said heating device, there are arranged heat conductors being constructed as a thin-layer or thick-layer heating device.

7. Pump according to claim 1, wherein said bearing shaft is fixedly arranged on said pump lower portion, such as being injected or pressed therein, wherein said drive rotor is rotatably supported on said bearing shaft in said lower region of said drive rotor by means of a radial bearing and is supported in an axial direction at said upper end of said impeller on said pump upper portion by means of an axial bearing.

8. Pump according to claim 7, wherein said axial bearing for said drive rotor is arranged at a central location at an uppermost region or in a region of said drive rotor being closest to said pump inlet and being arranged in extension of said bearing shaft, wherein an axial counter-bearing for said axial bearing is arranged on said pump housing or on said pump upper portion.

9. Pump according to claim 7, wherein said radial bearing is produced from plastics material, suitable ceramic material or sintered metal and is clamped to said drive rotor, wherein said radial bearing does not take up any forces in an axial direction of said rotor.

10. Pump according to claim 7, wherein said axial bearing comprises a different material and is fitted to said impeller, such as adhesively bonded or injected therein, wherein said axial bearing has a convex tip on said impeller made of plastics material, ceramic material or sintered metal.

11. Pump according to claim 7, wherein said axial bearing has on said pump upper portion and/or on said impeller graphite-containing plastics material or is formed from graphite-containing plastics material.

12. Pump according to claim 8, wherein in a state when said impeller in a longitudinal direction of a longitudinal centre axis is at a maximum distance from said pump inlet, between said axial bearing on said impeller and said axial counter-bearing, a spacing of a maximum of 5 mm is provided.

13. Pump according to claim 12, wherein in said state a free end or an end face of said bearing shaft is in abutment with an end or an inner end face of a receiving opening on said impeller for said bearing shaft.

14. Pump according to claim 13, wherein in said state, said drive rotor at a lower side thereof is not in abutment with said upper side of said pump lower portion, but instead has a spacing between 1 mm and 10 mm.

15. Pump according to claim 1, wherein ferromagnetic material or a rotor lamination bundle of said drive rotor is surrounded by a rotor housing and does not come into contact with water in said pump chamber, wherein said rotor housing is securely connected to said impeller in order to form a structural unit.

16. Pump according to claim 15, wherein said rotor housing is constructed in one piece with at least one portion of said impeller, wherein it forms at least partially a lower portion of said impeller.

17. Pump according to claim 16, wherein said rotor housing together with an internally raised region of said impeller is formed at a highest point of said axial bearing of said impeller according to claim 7.

18. Pump according to claim 16, wherein an upper portion of said impeller is constructed as an individual separate plastics material component and is secured to said lower portion of said impeller in a non-releasable manner by means of adhesive bonding, welding, ultrasonic welding or friction welding.

19. Pump according to claim 1, wherein said impeller is produced in a single component injection-moulding method or in a multi-component injection-moulding method and in one piece, and is connected as a complete component to said drive rotor to form a structural unit.

20. Pump according to claim 1, wherein said ferromagnetic material of said drive rotor is added to a plastics material and said entire drive rotor is produced with a plastics material injection-moulding method, wherein at least a portion of said impeller is also produced in the same step.

21. Pump according to claim 1, wherein said pump outlet is provided on a region being located furthest away from said pump inlet when viewed in a longitudinal direction of said pump.

22. Pump according to claim 1, wherein said pump inlet is constructed to be increasingly expanded in a direction away from said impeller to a diameter greater than said pump chamber in order to form a sump for a dishwasher or a washing machine.

23. Pump according to claim 1, wherein it is constructed to be installed vertically or to be installed with a vertically extending bearing shaft.

24. Water-carrying household appliance having a pump according to claim 1, wherein said pump is installed with a vertical bearing shaft, wherein said pump inlet faces upwards or is arranged at a top of said pump.

25. Water-carrying household appliance having a pump according to claim 24, wherein said pump outlet forms a lowest point of said pump chamber.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Embodiments of the invention are illustrated in the drawings and are explained in greater detail below. In the drawings:

[0035] FIG. 1 shows a schematic view of a dishwasher as a household appliance according to the invention with a pump according to the invention,

[0036] FIG. 2 shows a section through the pump according to the invention, and

[0037] FIG. 3 is an enlarged section through a modified impeller for a pump according to the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0038] FIG. 1 schematically illustrates a dishwasher 11 as a household appliance according to the invention having a housing 12 and a washing space 14 as a water processing space therein which in principle is constructed in conventional manner and as known. At the top in the washing space 14, a conventional washing arm 16 is indicated, wherein naturally also even more washing arms may be provided therein, in particular also in the lower region. It is supplied by means of a water line 38 which is illustrated with dashed lines. At the bottom, the washing space 14 has a base 17 which merges centrally into a large recess 18, which is constructed in a funnel-like manner and forms a sump 19 having a drain described above. In this instance, the recess 18 may also be partially covered by a grid, for example, as a filter. The walls of the cleaning space 14 and the base 17 generally comprise metal or high-grade steel. The recess 18 in turn may comprise plastics material, alternatively also metal.

[0039] At the bottom on the recess 18, a pump 22 according to the invention is arranged as an impeller pump and connected thereto in known manner so as to carry water. A connection of the pump 22 to the recess 18 advantageously has a seal which is not illustrated. A fixing between the two members, recess 18 and pump 22, may be carried out as desired.

[0040] According to FIG. 2, the pump 22 has a pump housing 23 having a pump inlet 24 and a pump outlet 25 of a circumferential pump chamber 26 which can be seen clearly in section. The pump inlet 24 is a short pipe socket along the longitudinal axis, which is illustrated with dot-dash lines, of the pump 22. The pump outlet 25 protrudes laterally and substantially tangentially, it has an angle of approximately 90° with respect to the longitudinal axis of the pump. It may be connected to the above-mentioned water line 38 directly or by means of valves.

[0041] FIG. 2 also shows how a pump chamber 26 is formed in the pump housing 23. The pump chamber 26 is formed in an upward direction by a pump upper portion 28, in which the pump inlet 24 is formed centrally, and in a downward direction by a pump lower portion 29, from which the pump outlet 25 extends at the bottom to the left. In an outward direction, the pump chamber 26 is delimited by the pump outer wall 33, which is advantageously constructed as a heating device described above. To this end, it may have a round-cylindrical metal pipe and thereon on the outer side heat conductors, advantageously thick-layer heat conductors. The metal pump outer wall 33 is sealed along the upper edge and along the lower edge by means of suitable seals on the pump upper portion 28 and on the pump lower portion 29 and is retained by them being pressed together. For this pressing together action, there is illustrated on the right a locking arm 34 which is constructed integrally on the pump upper portion 28 and which is engaged by means of a corresponding locking projection on the pump lower portion 29. In a circumferential direction, from two to six such locking arms 34 may be provided in a distributed manner.

[0042] The configuration of the pump upper portion 28 can be seen relatively easily in FIG. 2, wherein it particularly also has the locking arms 34 mentioned. The configuration of the pump lower portion 29 is slightly more complex, in this instance there is provided a downwardly pulled central region which forms a receiving recess 30. At the centre along the dot-dash longitudinal axis of the pump 22, a bearing receiving member 32 which also extends further in a downward direction is formed. Radially outside the receiving recess 30, a circumferential receiving protuberance 30′ which extends so to speak in an upward direction is provided. This receiving protuberance 30′ is angled in a radially outward direction through approximately 90° and then extends again substantially parallel with the longitudinal axis of the pump as far as a type of pump chamber base. This pump chamber base then merges into the pump outlet 25, as is also known from the pumps according to the prior art mentioned in the introduction. There is illustrated on the radially outwardly facing wall a guide vane 63 which is formed circumferentially and with a known inclination.

[0043] Substantially inside the receiving recess 30, a drive rotor 35 is rotatably supported. The drive rotor 35 has ferromagnetic material 36 which is arranged in an annular manner and which is arranged in a rotor housing 37 and is surrounded thereby. 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 may advantageously comprise sintered metal or ceramic material.

[0044] According to a possibility mentioned in the introduction, the drive rotor 35 may have a separate ring made of ferromagnetic material 36 which is either placed or injected in a rotor housing 37 made of plastics material. The rotor housing 37 may also comprise at least two portions, which surround the ferromagnetic material 36 and which are adhesively bonded or welded to each other. The radial bearing 39 may be pressed in and where applicable also adhesively bonded or welded.

[0045] In an alternative embodiment of the invention, the ferromagnetic material 36 may be mixed with plastics material in granular or powdered form and the drive rotor 35 can then in a manner of speaking be cast or injected in an integral manner. In this instance, the radial bearing 39 can also be injected.

[0046] A bearing shaft 41 is inserted and secured in the bearing receiving member 32, preferably by means of a press-fit or clamping fit. Alternatively, the bearing shaft 41 may also be injected into the pump lower portion 29 or into the bearing receiving member 32. The bearing shaft 41 may comprise metal or high-grade steel, alternatively it may also comprise a suitable stable plastics material, for example, a fibre-reinforced plastics material. It thus forms a fixed bearing shaft on which the drive rotor 35 is rotatably supported by means of the radial bearing 39.

[0047] In the receiving protuberance 30′ which surrounds the receiving recess 30 and consequently also the drive rotor 35 in a radial direction, a circumferential drive stator 43 is arranged. The drive stator 43 has a stator winding 45 which extends or is arranged radially at the outer side and with little spacing therefrom in a radially inner direction a stator lamination bundle 46 is arranged. This serves in known manner to guide the magnetic field in a desired manner. The drive stator 43 may either be constructed as an independent structural unit and then secured in the receiving protuberance 30′, for example, securely bonded or securely locked. Alternatively, as illustrated herein, it may be cast in a durable and stable manner as a structural unit or also stator winding 45, on the one hand, and stator lamination bundle 46, on the other hand, by means of casting resin 47. Electrical connections on the stator winding 45 are not illustrated in this instance but can be readily envisaged and implemented.

[0048] Above the drive rotor 35 there is provided an impeller 50 which is constructed in a manner known per se. The impeller 50 has a lower covering plate 52 which centrally has a projection 53 which extends upwards by a significant distance. A bearing tip 55 mentioned in the introduction is arranged on the projection 53 as an axial bearing or as part of an axial bearing. The bearing tip may be constructed and secured in a manner mentioned in the introduction, for example, it may be an adhesively bonded or injected component made of metal or ceramic material.

[0049] Above the lower covering plate 52, an upper covering plate 57 extends and impeller blades 58 are indicated therebetween. The impeller 50 may be produced either in a manner known per se from two members, that is to say, substantially from a lower covering plate 52 and an upper covering plate 57. The impeller blades 58 may in this instance be arranged on one of these covering plates or be produced in one piece and integrally therewith. The two members of the impeller are then connected to each other, for example, adhesively bonded or welded. Alternatively, an impeller may also be produced in one piece, as known from DE 102012209832 B3. However, for example, the bearing tip 55 must then be subsequently fitted.

[0050] The impeller 50 may be connected to the drive rotor 35 in a different manner. The upper end of the bearing shaft 41 protrudes from below into the impeller 50, but a radial spacing should be provided in this instance so that at least during pump operation or during normal operation the bearing shaft 41 does not abut or rub on the impeller 50 in a radial direction. It can be seen that, between the uppermost end of the bearing shaft 41 and the opposing base face of the impeller 50, a small spacing is provided, for example, a few millimetres. This has been explained in the introduction. This spacing serves to ensure that the structural unit comprising the drive rotor 35 and impeller 50 can be moved in the longitudinal direction of the pump slightly in a downward direction. In this instance, the upper end of the bearing shaft 41 should strike the impeller 50 in an axial direction at the inner side before the lowest region of the drive rotor 35 or the rotor housing 37 thereof moves into abutment with the receiving recess 30. Alternatively, the impeller 50 may also be supported with another radial bearing at the upper end of the bearing shaft 41.

[0051] The axial bearing mentioned in the introduction is formed by the bearing tip 55 on the impeller 50. An axial counter-bearing 61 is arranged on a bearing holder 60 which is provided inside the pump inlet 24, at locations where the pump inlet 24 virtually opens in the pump chamber 26. The bearing holder 60 may be retained in a manner known per se by means of two to four radial struts. The axial counter-bearing 61 may be adhesively bonded to the bearing holder 60, alternatively it may be injected on or injected in. It advantageously comprises a suitable bearing material, for example, ceramic material or sintered metal, potentially also a plastics material such as Delrin or the like.

[0052] FIG. 2 shows that the drive rotor 35 and consequently a pump drive is constructed as a wet runner. Water can run inside the pump chamber 26 between the drive rotor 35 and pump lower portion 29 in a downward direction as far as the receiving recess 30. In this manner, the drive rotor 35 may be cooled by water. Furthermore, no problems arise with a complex seal.

[0053] The drive stator 43, in particular the stator winding 45, as a result of the special arrangement within the receiving protuberance 30′, can also be effectively cooled by means of water which is circulating in the pump chamber 26. A cooling is possible in the upper region of the receiving protuberance 30′ which extends substantially in a radial direction. A relatively direct cooling of the stator winding 45 at the radially outwardly facing side is also possible, at locations where water is present in the region of the guide vanes 63. On the radially inwardly facing side of the receiving protuberance 30′, that is to say, in the direction towards the drive rotor 35, water is also present and can thus also cool the stator lamination bundle 46 or via this the stator winding 45.

[0054] Furthermore, it can be seen in FIG. 2 that the pump 22 is relatively short in an axial longitudinal direction as a result of a high level of axial integration.

[0055] An alternative embodiment for a pump 22 is illustrated in FIG. 3. A pump housing 23 having an illustrated pump upper portion 28 and pump lower portion 29, in particular with the receiving recess 30, is constructed according to FIG. 2. This also applies to a bearing receiving member 32 together with the bearing shaft 41 which is securely arranged therein. The structural unit comprising the drive rotor 135 and impeller 150 is constructed differently in this instance. In this instance, ferromagnetic material 136 is constructed for the drive rotor 135 in annular form, but not with a rectangular cross section, but instead pulled slightly upwards in a direction towards the centre at the upper side. This ferromagnetic material 36 is overmoulded with a rotor housing 137 which at the same time forms a lower covering plate 152 for the impeller 150. The central raised portion 153 is also formed directly thereon. A radial bearing 139 can in turn be directly injected therein, alternatively subsequently secured by means of clamping or the like.

[0056] An upper covering plate 157 of the impeller 150 is produced separately and is connected thereto, for example, adhesively bonded. Impeller blades 158 may in turn be formed on one of the two portions, advantageously this is recommended to be on the upper covering plate 157.

[0057] Alternatively, a separate rotor housing 137 could be dispensed with completely and the entire drive rotor, potentially with the exception of an upper covering plate of the impeller and/or the impeller blades, could be produced by means of injection-moulding from a plastics material to which a high proportion of ferromagnetic material is added.