EP3021732A1

EP3021732A1 - Water-carrying domestic appliance with a pump unit comprising a slit tube

Info

Publication number: EP3021732A1
Application number: EP14736867.4A
Authority: EP
Inventors: Igor Hoffmann; Stephan Lutz; Hans-Holger Pertermann
Original assignee: BSH Hausgeraete GmbH
Current assignee: BSH Hausgeraete GmbH
Priority date: 2013-07-19
Filing date: 2014-07-10
Publication date: 2016-05-25
Also published as: CN105324062A; WO2015007616A1; DE102013214190A1; CN105324062B

Abstract

The invention concerns a water-carrying domestic appliance (1), in particular a dishwasher, with at least one pump unit (9, 12) which comprises an electric motor (17) with a rotor unit (18) mounted in a chamber which, at least during operating phases, conveys liquid, and with a stator unit (24) rigidly disposed in a dry outer chamber, as well as with a tube section (20) disposed between the rotor unit (18) and stator unit (24). The domestic appliance is designed such that the tube section (20) is formed from an easily flowable plastics having a melt flow index of more than 10 cm3 per 10 minutes.

Description

Water-bearing household appliance with a one can

having pumping unit

The invention relates to a water-conducting household appliance with at least one

Pump unit which comprises an electric motor with a rotor unit held in liquid and a stator unit fixedly arranged in a dry outer space and a pipe section arranged between rotor unit and stator unit, according to the preamble of claim 1.

It is known in a water-conducting household appliance such as a

Dishwasher, a washing machine, a tumble dryer or similar devices of the so-called "white goods" to circulate and / or pumping off the optionally with detergent and / or dirt offset water to provide at least one pump unit having an electric motor with a rotor unit held in liquid and a The rotor unit can be lubricated by its arrangement in the liquid also from this, so that optionally one in a dry outer space fixedly arranged stator and a arranged in the magnetic gap between the rotor unit and stator unit of non-magnetic material Such an arrangement with a tube section in the magnetic gap is often also referred to as a canned tube arrangement, in particular a containment shell, in which the canned tube is filled with a liquid such as, for example, with a fluid or other fluid and dic remove these from the outside. Thus, in the radial direction across the axial length of the split tube, the split tube provides separation between its fluid-filled interior housing the shaft of the pump and the rotor unit mounted thereon and the dry exterior housing the stator unit. For high magnetic efficiency, it is important to keep the thickness of the magnetic gap as small as possible. Since the gap proportionately of wall material of the pipe section and liquid and since the thickness of the liquid-filled portion for tolerance and contamination reasons can not be made arbitrarily small, a reduction in the wall thickness of the pipe section is crucial for minimizing the gap thickness. The effect becomes especially strong when ferrite magnets Find use, which have a high magnetic permeability, but a low magnetic induction compared to magnets based on rare earths. Since the prices of magnets based on rare earths have developed very unfavorably, it is desirable to switch to ferrite magnets as far as possible. At the same time it should be remembered that often the can together with the cost

Bearing shields and other construction elements from a part as a plastic pot is made by injection molding. The plastics used should be inexpensive, resistant to hydrolysis and chemicals as well as stable in temperature with high rigidity. However, the high filling levels with glass fibers required for this purpose limit the processing capability, especially with thin wall thicknesses.

The invention is based on the problem of bringing the various requirements for the arranged in the magnetic gap pipe section between the rotor unit and the stator of the pump unit as well as possible in harmony with each other. The invention solves this problem by a water-conducting household appliance with the features of claim 1. Further advantages and features and further developments of the invention are set forth in claims 2 to 1 1, the features of which can be implemented individually or in combination with each other. With the invention in training according to claim 1, a household appliance is provided, in which characterized in that a pipe section in the magnetic gap between a held in an at least in operating phase liquid space rotor unit and a fixed in a dry outer space stator made of a flowable plastic with formed a melt flow index of more than 10 cm ³ per 10 minutes, the injection molding of this pipe section is simplified. This can be done sufficiently fast so that very small wall thicknesses can be formed for minimizing the magnetic gap.

Particularly favorable, the pipe section has a wall thickness of less than 0.75 millimeters. As a result, ferrite arrangements for the rotor unit can form a sufficiently high efficiency. It is possible to dispense with such arrangements based on rare earths. For the thinnest possible wall thicknesses, it is advantageous if the said pipe section is formed from a plastic having a melt flow index of more than 30 cm ³ per 10 minutes at 230 ° C.

Technically, the production of the pump unit is particularly simple if the pipe section expediently part of a one-piece housing part of the

Pump housing is, in particular forms an integral part of the pump housing. In particular, this one-piece housing part can form a rotor housing, in whose rotor chamber the drive shaft is accommodated with the rotor unit of the motor of the pump unit attached to it. In particular, a rear housing bottom and / or a front end section bounding the hydraulic chamber of the pump unit may be integrally formed on the pipe section. Then, one or more additional sealing points between the pipe section and one or more attachment components, such as e.g. a separate, rear housing bottom or a hydraulic chamber limiting, separate front end component can be avoided.

Alternatively, it is also possible that the pipe section is sealed as a separate component embedded in a multi-part pump housing to thereby only have to use the expensive material in the actual canned area, but otherwise to be able to resort to cheaper materials.

In particular, the said pipe section in both cases is a so-called. Canned in the magnetic gap between the rotor and stator. With the plastic used, the pipe section can form an injection-molded part or a component of an injection-molded part, and nevertheless the o. G. have thin wall thickness.

For the necessary mechanical stability, even with thin wall thickness, the plastic of the pipe section is in particular highly reinforced and has a glass fiber or carbon content of at least 30%, in particular of at least 40%.

In particular, a dishwasher is designed according to the invention. Other advantageous developments of the invention are given in the dependent claims.

Further advantages and features will become apparent from the drawing illustrated and described below embodiments of the subject invention.

In the drawing shows:

1 shows an exemplary domestic appliance, here a dishwasher, in a schematic, partially cutaway view with a circulating and / or suction pump unit,

2 shows a cross-sectional view of a pump unit, FIG. 3 shows a section approximately along the line III-III in FIG. 2,

4 is a cross-sectional view of an alternative pump unit,

5 shows a section approximately along the line V-V in Figure 4,

Elements with the same function and mode of operation are each provided with the same reference numerals in the figures.

The household appliance 1 shown schematically in FIG. 1 forms an example dishwashing machine here. As explained above, other household appliances, in particular large appliances, come into consideration for an embodiment according to the invention.

The dishwashing machine 1 shown schematically here is a domestic dishwasher and has a washing container 2 for receiving ware to be processed such as dishes, pots, cutlery, glasses, cooking utensils u. on. Of the

Washing container 2 may have an at least substantially rectangular floor plan with a front side V facing a user in the operating position. The washing container 2 can be closed by a door 3. This door 3 is shown in Figure 1 in the closed position and, for example, swiveled about a lower horizontal axis 3a in the direction of the arrow 3d. Another, different from the pivoting opening movement is possible. The items to be washed can be held in at least one washing basket 4; Here, for example, exactly two crockery baskets 4, 5 are provided one above the other in the washing container 2. The number of washing baskets 4, 5 may vary depending on the extent and type of the dishwasher 1. Also a so-called cutlery drawer may be additionally provided. These crockery baskets 4, 5 are sprayers 6, 7, for example, over long in the radial direction, each rotatable about a center spray arms and / or individual nozzles with fresh water FW and / or with circulating water, which may be mixed with detergent, so-called wash liquor S, acted upon.

Furthermore, the rinsing baskets 4, 5 can be displaced forward, for example, on rollers 10, so as to achieve an access position for the user, in which the rinsing baskets 4, 5 can be conveniently loaded and unloaded. As webs for the rollers 10 lateral rails in the washing compartment 2 are provided. In addition, at the respectively in the direction of the front side V-facing edge planes of the washing baskets 4, 5 Zug- and

Push handles to simplify the insertion and removal of the washing baskets 4, 5 may be provided.

The fresh water FW and / or the circulating and with cleaning agents and / or rinse aid or other agents and / or contaminants from the washware added wash liquor S runs after its or its distribution in the washing compartment 2 and on the items to be washed down over a in the bottom portion 8 of Rinse tank 2 arranged

Collecting pot with sieve unit 1 1 to one of these downstream circulating pump unit (circulating pump) 12, from which it is here exemplified by at least one heater shown only schematically in Figure 1 13 again to a manifold 14 and from there to the said sprayers 6, 7 is passed , Between the collecting pot, the pump unit 12, the heater 13, the manifold 14 and the spray 6, 7 is in each case a liquid connection, in particular in the form of a pipe or hose, provided. For pumping wastewater AW, from the washing container, a pump unit or a wastewater pump 9 is provided, which in a Drain pipe is inserted. About this drain pipe wastewater AWaus the machine 1 is passed.

The pump units 9, 12 can also be combined with each other, so that then only a single pump unit is present in total.

The at least one pump unit 9, 12 here comprises a centrifugal pump with a

Impeller 15, which can be designed differently depending on the version. This is driven by a central drive shaft 16 which is mounted wet in its end region. The drive shaft 16 is rotatable by an electric motor 17, i. can be driven, wherein the electric motor 17 comprises a arranged on the drive shaft 16 and held in fluid with this rotor unit 18 to which radially outward also in the

Liquid space lying gap region 19 connects. The term "held in liquid" means that the corresponding receiving space for the rotor unit can be flooded at least during operation by liquid such as rinsing liquor or water / wastewater

Liquid is alternatively possible.

Connected radially outward to the gap region 19 is a tube section 20 as a one-part or multi-part component of a housing 21, which delimits the wet inner region 22, in which the drive shaft 16 is accommodated with the rotor unit 18, from a dry outer space 23. In the dry outer space 23, a stator 24 is fixed, which here in particular comprises a plurality of stator plates, each of

Statormagnetspulen 25 are enclosed. The pipe section 20 is thus located parallel to the gap region 19 and between the rotor unit 18 and the stator unit 24 in the magnetic gap. The thickness of this gap is defined by the sum of the thickness of the liquid gap 19 and the thickness of the pipe section 20. As mentioned above, the thickness of the magnetic gap for a high magnetic efficiency should be as small as possible. To make this possible, the pipe section 20 consists of a readily flowable plastic with a melt flow index of more than 10 cm ³ per 10 minutes.

In this case, the pipe section 20 has a previously unknown thin wall thickness of less than 0.75 millimeters.

In particular, the pipe section 20 made of a plastic with a

Melt flow index of more than 30 cm ³ per 10 minutes at 230 ° C may be formed.

As shown here in Figure 2, in particular that housing part 21 which receives the drive shaft 16 with the rotor unit 18, in spite of its course of varying thicknesses may be formed as a whole integral injection molded part. It comprises the tube section 20 surrounding the rotor unit 18 radially and preferably round-cylindrical, which forms a so-called gap tube in the magnetic gap between rotor 18 and stator unit 24. In particular can - as here in the embodiment of Figure 2 - to the

Pipe section 20 at the impeller 15 remote from the axial end and thus outside of the pipe section 20, which serves as a rotor chamber for accommodating the

Rotor unit 18 acts, a housing bottom 31 may be formed, so that a closed-end containment shell is formed. In particular, a so-called B or rear bearing receptacle or a so-called B or rear bearing for the drive shaft 16 may be integrally formed on the housing bottom 31 on the inside. Additionally or independently thereof, on the impeller 15 facing, a passage for the drive shaft 16 having, axial end of the can 20, a front

End section 29 integrally formed. For this is the drive shaft 16 with the end attached to her impeller 15 in a hydraulic chamber 28 of the

Pumping unit 9, in particular liquid pump forth. This front

End section 29 may in particular have an end-side receiving wall or a flange for receiving a so-called A or front bearing holder 30. The front end wall preferably also forms a portion of the boundary of the hydraulic chamber 28 of the pump unit 12, in which the impeller 15 is housed. In summary, therefore, a one-piece housing part 21 is provided for the drive shaft 16 with the rotor unit 18, which consists of an axial, preferably cylindrical, preferably substantially circular, pipe section 20, which has a rotor chamber for accommodating the rotor unit 18 in the radial direction its axial longitudinal extent considered limited, a rear, integrally molded housing bottom 31 which closes the pipe section 20 liquid-tight at its rear axial end, and a front end portion 29 together. In the hydraulic chamber or impeller chamber 28, the impeller 15 is housed to suck Spülflottenflüssigkeit through a central intake manifold 26 from the outside in the axial direction (relative to the elongated drive shaft) into the hydraulic chamber 28 and with a radial direction component through a

To challenge pressure port 27 to the outside of the pump unit 9.

Alternatively, the tube section 20, which is made of the easily flow-coated plastic with a melt flow index of more than 10 cm ³ per 10 minutes, can also be mounted in the pump housing as a separate component (see FIG. 4). At its front end, this is preferably coupled via an additional sealing point with a separate, front end part or end piece 32, which adjoins the hydraulic chamber 28. Conveniently, the rear end of the pipe section 20 may be provided with a housing bottom 31 integrally formed and thus a containment shell may be formed, the front separate end portion 32 may be made of a less flowable and thus less expensive plastic than the pipe section 20. The high price of the expensive and despite its high melt flow index ^' highly reinforced plastic for the pipe section 20 would be less significant in this version of the pump unit in terms of their total cost.

A version in which the B-bearing and the cylindrical, cuff-like surrounding pipe section 20 are made of a first, very easily flowable material and the opposite, the impeller 15 facing end wall of the housing 21 form separate units, is shown in Figure 4. It would also be possible alternatively that only the cylindrical sleeve 20 is formed from the plastic material with a high melt flow index. If appropriate, the housing bottom 31 may also be made of a less flow-smooth plastic than the pipe section 20 accommodating the rotor unit 18. Possibly. it may also be formed as a separate attachment, which can be suitably coupled in a manner analogous to the separate front end portion 32 with the aid of an additional seal to the rear end of the pipe section 20 liquid-tight by means of appropriate fasteners. In the various versions, therefore, the pipe section 20 itself can form an injection-molded part or a component of an injection-molded part. The plastic of this

Tube section 20 is here polypropylene-based and at the same time highly reinforced - for example by a high glass fiber content of significantly more than 30%, in particular more than 40%, or by a carbon fiber content. Of course, to reinforce the plastic material of the pipe section or can 20 also other reinforcing, in particular the tensile strength, impact resistance, and / or compressive strength increasing additives are mixed into the easily flowable plastic material of the can 20. In addition or independently thereof, exterior and / or exterior

Interior coatings of the pipe section 20 may be advantageous with reinforcing materials.

Here, as the plastic of the tube section 20 and in a one-piece construction of the entire housing part 21, the area adjacent to the rotor chamber and the impeller is preferably a polypropylene having a melt flow index between 10 and 40 cm ³ per 10 minutes, preferably around 30 cm ³ per 10 minutes, used. If, for example, only the split tube 20 is designed like a sleeve as a single part, so can

expediently, this only be formed by a high-strength plastic (for example PPS), which has a melt flow index of more than 10 cm 3 per 10 minutes, and so be mounted in the pump housing 21, while the remaining parts of the Gesäuteiles 21 and the other pump housing from a less flowable plastic are made.

Overall, it is possible by the execution of the cylindrical gap tube 20 with wall thicknesses of media-stable plastics and a wall thickness of less than 0.75 millimeters to produce even with ferrite magnet highly efficient pump drives that are otherwise possible only with rare earth based magnet. This results in space advantages, weight savings, efficiency improvements and

Cost reductions. It can be advantageous, in particular, if, to further reduce the radial distance between the rotor unit and the stator unit, the rotor unit is free of envelopes at its radially outer edge, ie has bare magnetisable material, in particular ferrite material there. In the figure 2 is the bare outside of the magnetizable body 34 of the rotor unit designated 33. This results in a further improvement in the driving efficiency of the electric motor of the pump unit, which drives the impeller via the fixed on the drive shaft rotor unit. An existing of magnetizable material body of the preferably cylindrical rotor unit is expediently mounted on a radially inner support body 35, which is preferably made of plastic. This inner support body sits around the drive shaft firmly on. It has at its end facing the impeller a front, radially outwardly projecting retaining flange 36 and at its end facing away from the impeller a rear, radially outwardly projecting

Retaining flange 37. Between the two lateral retaining flanges is the

magnetizable body supported on the cylindrical outer surface of the support body, in particular attached thereto.

Conveniently, to further minimize the magnetic gap between the rotor unit and the stator unit, the radially inner edge of the stator unit is as gapless as possible, i. directly contacting on the outer wall of the pipe section or

Canned pipe on. For the lower the magnetic gap, the more effective the magnetic interaction, in particular magnetic attraction between the magnetic field generated by the stator and the magnetic field generated by the rotor unit.

LIST OF REFERENCE NUMBERS

Home appliance, 22 wet interior,

Washing container, 23 dry outdoor space,

Door, 24 stator unit,

a swivel axis, 25 stator solenoid coils

d swivel direction, 26 central intake manifold

Crockery basket, 27 discharge nozzles

Crockery basket, 28 hydraulic chamber

Spraying device, 29 front end section

Spraying device, 30 A bearing holder

Floor area, 31 caseback

Pump unit, 32 front, separate end piece0 rolls, 33 bare outside

1 sieve unit, 34 magnetizable body

2 pump unit, 35 supporting bodies

3 heaters, 36, 37 lateral retaining flanges

4 distributors,

5 impeller,

6 drive shaft,

7 electric motor,

8 rotor unit,

9 gap area in the liquid space,

0 pipe section,

1 housing,

Claims

CLAIMS:

1. Water-conducting household appliance (1), in particular dishwashing machine, with at least one pumping unit (9; 12), which has an electric motor (17) with a rotor unit (18) held in a space carrying liquid at least in operating phases and one fixed in a dry outer space Stator unit (24) and with a between rotor unit (18) and stator unit (24)

comprises arranged pipe section (20),

characterized,

the pipe section (20) is formed from a readily flowable plastic having a melt flow index of more than 10 cm ³ per 10 minutes.

2. Household appliance (1) according to claim 1,

characterized,

the pipe section (20) has a wall thickness of less than 0.75 millimeters.

3. Household appliance (1) according to one of claims 1 or 2,

characterized,

that the pipe section (20) is formed of a plastic having a melt flow index of more than 30 cm ³ per 10 minutes at 230 ° C.

4. Household appliance (1) according to one of claims 1 to 3,

characterized,

the pipe section (20) forms part of a one-piece housing part (21).

5. Household appliance (1) according to one of claims 1 to 3,

characterized,

the pipe section (20) is sealed in a multipart pump housing (21).

6. Household appliance (1) according to one of claims 1 to 5, characterized,

the pipe section (20) is a so-called split pipe in the magnetic gap between rotor (18) and stator unit (24).

7. Household appliance (1) according to one of claims 1 to 6,

characterized,

the pipe section (20) forms an injection-molded part or a component of an injection-molded part.

8. Household appliance (1) according to one of claims 1 to 7,

characterized,

the plastic of the pipe section (20) is polypropylene-based.

9. Household appliance (1) according to one of claims 1 to 8,

characterized,

that the plastic of the pipe section (20) is highly reinforced.

10. Household appliance (1) according to one of claims 1 to 9,

characterized,

the plastic has a glass fiber content of at least 30%, in particular of at least 40%.