ELECTRIC DRIVE MOTOR, PUMP, AND A DOMESTIC APPLIANCE COMPRISING SUCH A PUMP

Abstract

An electric drive motor for a pump includes an electrically actuatable stator winding, and a rotor which is mounted for rotation in a field of the stator winding in the presence of an annular gap. The rotor includes a motor shaft, a magnet carrier disposed on the motor shaft, and at least one permanent magnet arranged on the magnet carrier. The magnet carrier is made from a ferromagnetic chrome steel.

Claims

1-15. (canceled)

16. An electric drive motor for a pump, comprising: an electrically actuatable stator winding; and a rotor mounted for rotation in a field of the stator winding in the presence of an annular gap, said rotor including a motor shaft, a magnet carrier disposed on the motor shaft, and at least one permanent magnet arranged on the magnet carrier, said magnet carrier being made from a ferromagnetic chrome steel.

17. The electric drive motor of claim 16, wherein the chrome steel is a ferritic or martensitic chrome steel with a chrome proportion of at least 10.5%.

18. The electric drive motor of claim 16, wherein the chrome steel is a nickel-free chrome steel.

19. The electric drive motor of claim 16, wherein the chrome steel has a chrome proportion of 16% to 18%.

20. The electric drive motor of claim 16, wherein the chrome steel has a chrome proportion of approx. 17%.

21. The electric drive motor of claim 16, wherein the chrome steel is of a material number 1.4016 according to EN 10027-2 (X6Cr17, AISI 430).

22. The electric drive motor of claim 16, wherein the magnet carrier includes a laminated core of several metal sheets stacked on top of one another and connected to one another.

23. The electric drive motor of claim 16, wherein the motor shaft is made from a chrome steel.

24. The electric drive motor of claim 23, wherein the chrome steel for the motor shaft is a curable chrome steel.

25. The electric drive motor of claim 23, wherein the chrome steel for the motor shaft is austenitic or martensitic chrome steel.

26. The electric drive motor of claim 23, wherein the chrome steel for the motor shaft has a chrome proportion of 15% to 17% and a nickel proportion of 3% to 5%.

27. The electric drive motor of claim 26, wherein the chrome proportion is approx. 16% and the nickel proportion is approx. 4%.

28. The electric drive motor of claim 23, wherein the chrome steel for the motor shaft, is of a material number 1.4542 according to EN 10027-2 (X5CrNiCuNb16-4, AISI 630).

29. The electric drive motor of claim 16, wherein the rotor has a number of permanent magnets arranged in a distributed manner about the magnet carrier, said magnet carrier having a polygonal cross-section, each of the permanent magnets having a planar base area pointing in a direction of the magnet carrier.

30. The electric drive motor of claim 29, wherein the magnet carrier has a hexagonal cross section.

31. The electric drive motor of claim 16, wherein the rotor has a number of permanent magnets arranged in a distributed manner about the magnet carrier, said magnet carrier having a circular cross-section, each of the permanent magnets having a base area which points in a direction of the magnet carrier and has a circular arc-shaped cross-section.

32. The electric drive motor of claim 29, further comprising a plastic cage produced by injection molding around the magnet carrier to thereby fasten the permanent magnets on the magnet carrier.

33. The electric drive motor of claim 16, wherein the magnet carrier has a hub for receiving the motor shaft, said hub having an inner casing wall provided with projecting ribs.

34. The electric drive motor of claim 33, wherein the ribs extend in an axial direction.

35. A pump, comprising an electric drive motor which includes an electrically actuatable stator winding, and a rotor mounted for rotation in a wet area of the pump, said rotor comprising a motor shaft, a magnet carrier disposed on the motor shaft and made from a ferromagnetic chrome steel, and at least one permanent magnet arranged on the magnet carrier and having an outer surface in contact with a liquid of the wet area which is disposed in an annular gap of the electric drive motor between the stator winding and the rotor.

36. The pump of claim 35, further comprising a pump wheel configured for propulsion by the electric drive motor, said motor shaft of the electric drive motor having a knurling, to which the pump wheel is fastened.

37. The pump of claim 35, wherein the stator winding of the electric drive motor is arranged in a dry environment outside the wet area.

38. A domestic appliance, comprising: an electric drive motor comprising an electrically actuatable stator winding, and a rotor mounted for rotation in a field of the stator winding in the presence of an annular gap, said rotor including a motor shaft, a magnet carrier disposed on the motor shaft and made from a ferromagnetic chrome steel, and at least one permanent magnet arranged on the magnet carrier; and/or a pump comprising an electric drive motor which includes a rotor mounted for rotation in a wet area of the pump, said rotor comprising a motor shaft, a magnet carrier disposed on the motor shaft and made from a ferromagnetic chrome steel, and at least one permanent magnet arranged on the magnet carrier and having an outer surface in contact with a liquid of the wet area which is disposed in an annular gap of the electric drive motor between a stator winding and the rotor.

39. The domestic appliance of claim 37, constructed in the form of a dishwasher, washing machine, vacuum cleaner, or dryer.

Description

[0033] Different concrete exemplary embodiments of inventive electric drive motors are explained in more detail in the description which follows with reference to the appended figures. Concrete features of these exemplary embodiments can, independently of the concrete association in which they are mentioned, if necessary also considered individually or in combination, represent general features of the invention, in which:

[0034] FIG. 1 shows a cross-sectional view of an exemplary pump of a domestic appliance with an inventive electric drive motor in the form of a wet running meter pump drive motor,

[0035] FIG. 2 shows a perspective exploded view of a first embodiment of a permanent magnet inner rotor of the inventive electric drive motor;

[0036] FIG. 3 shows a perspective view of the permanent magnet inner rotor according to FIG. 2 in an assembled state;

[0037] FIG. 4 shows an individual permanent magnet of the electric drive motor according to the first embodiment according to FIG. 2 and FIG. 3 in a front view, a side view, a cross-sectional view and in a perspective representation;

[0038] FIG. 5 shows a cross-sectional view of the assembled permanent magnet inner rotor of the first embodiment according to FIG. 3;

[0039] FIG. 6 shows an individual permanent magnet of the electric drive motor according to a second embodiment in a front view, a side view, a cross-sectional view and in a perspective representation;

[0040] FIG. 7 shows a cross-sectional view of the assembled permanent magnet inner rotor of the second embodiment according to FIG. 6, and

[0041] FIG. 8 shows a perspective exploded representation of a third embodiment of a permanent magnet inner rotor of the inventive electric drive motor.

[0042] A pump 1 of a domestic appliance shown by way of example in FIG. 1 has a pump housing 2, in which a pump wheel 3 is rotatably arranged. The pump wheel 3 has a number of blades 4, which are embodied and arranged to axially take in liquid via an inlet opening 5 and to radially discharge the same via an outlet opening 6. In the present exemplary embodiment, the pump 1 then forms a centrifugal pump in the design of a radial pump. The pump wheel 3 sits on a motor shaft 7 of a brushless direct current wet running meter pump drive motor 8 in a torsion-resistant manner.

[0043] The direct current wet running meter pump drive motor 8 is arranged in a motor housing 9. The motor housing 9, in the case of the present exemplary embodiment, is directly connected to the pump housing 2. If necessary the motor housing 9 can form an assembly together with the pump housing 2, or even be embodied in one piece. The direct current wet running meter pump drive motor 8 has an electrically actuatable stator winding 10 and a rotor 13 which can be driven in the field of the stator winding 10 and is rotatably mounted by means of the motor shaft 7 in the field between two opposing bearings 11.

[0044] The direct current wet running meter pump drive motor 8 of the exemplary embodiment shown is embodied as a wet running meter motor through which liquid passes, in which the rotor 13 is mounted in a wet area 16 within a motor housing 9, which is flooded by liquid from the pump housing 2. The stator winding 10 is arranged here in a dry environment outside of the motor housing 9.

[0045] In the exemplary embodiment shown, the rotor 13 has substantially the motor shaft 7, a magnet carrier 14 fastened to the motor shaft 7 in a torsion-resistant manner and permanent magnets 15 fixed on the magnet carrier 14 by means of a plastic cage 17 produced by means of injection molding.

[0046] This permanent magnet inner rotor is shown in more detail in an exploded representation in FIG. 2.

[0047] The motor shaft 7 has a front shaft end 7a, on which the pump wheel 3 is to be fastened. On this front shaft end 7a, the motor shaft 7 has a knurling 18 on its outer casing wall, said knurling being embodied to fix the pump wheel 3 to the motor shaft 7 in a torsion-resistant manner.

[0048] The permanent magnets 15 of the rotor 13 are in direct contact with the liquid (FIG. 1) with their outer surfaces 15.1 in the wet area 16 in the region of an annular gap 12 between the rotor 13 and the stator winding 10. The permanent magnets 15 are produced from a ferromagnetic material.

[0049] The rotor 13 mounted in a rotationally drivable manner in the wet area 16 of the pump 1 has a number of permanent magnets 15 arranged in an evenly distributed manner across a periphery, the outer surfaces 15.1 of which are in contact with a liquid of the wet area 16 which is disposed in the annular gap 12 of the electric drive motor 8.

[0050] In order to fasten the number of permanent magnets 15 on the magnet carrier 14, said permanent magnets 15 being arranged in a distributed manner on at least one lateral area 14.1 of the magnet carrier 14, the permanent magnets 15 are held in a form-fit manner in the manner of a frame on the magnet carrier 14 on the edge side by means of a plastic cage 17 produced by means of injection molding the magnet carrier 14.

[0051] To ensure that the plastic cage 17 produced by injection molding the magnet carrier 14 can hold the permanent magnets 15 in a form-fit manner on the magnet carrier 14, each permanent magnet 15 has at least one bevel 19 running around the outer surface 15.1, said bevel being filled by the plastic cage 17, as a result of which the respective permanent magnet 15 is enclosed in a form-fit manner by the plastic cage 17.

[0052] In the first embodiment according to FIG. 2 to FIG. 5, the magnet carrier 14 has a polygonal, in particular hexagonal cross-section. The magnet carrier 14 can be embodied to be solid, or structured in a manner known per se to the person skilled in the art from a stack of a number of polygonal, in particular hexagonal punched sheets.

[0053] The magnet carrier 14 has a hub 20, in which the motor shaft 7 is received. For a secure fastening of the motor shaft 7 in the magnet carrier 14, protruding ribs 21 are provided on an inner casing wall 20.1 of the hub 20, said ribs extending in particular in the axial direction.

[0054] A separate permanent magnet 15 sits in each case on each individual, in particular rectangular lateral area 14.1 of the cross-sectionally polygonal, in particular hexagonal magnet carrier 14. Each permanent magnet 15 has a planar base area 15.2 pointing in the direction of the magnet carrier 14 and touching the lateral area 14.1 of the magnet carrier 14 face to face.

[0055] As shown in particular in the representations in FIG. 4, each permanent magnet 15 has a front end wall 15.3, a rear end wall 15.4, a leading side wall 15.5 in the direction of rotation of the rotor 13 and a trailing side wall 15.6. The inventive at least one bevel 19 is formed in that the front end wall 15.3, the rear end wall 15.4, the leading side wall 15.5 and the trailing side wall 15.6 are each tapered inwards from a position L at right angles to a base area 15.2 of the permanent magnet 15 pointing in the direction of the magnet carrier 14 about an angle a such as is shown in particular in the cross-sectional representation in FIG. 4. In accordance with the invention the angle a can lie in a value range of 1 to 20 degrees and has, particularly in the exemplary embodiments shown, a value of approx. 8 degrees.

[0056] The four side edges 15a of the permanent magnet 15, which directly connect the front end wall 15.3, the rear end wall 15.4, the leading side wall 15.5 and the trailing side wall 15.6 in each case, are embodied rounded in order to form a single bevel 19 which runs around the outer surface 15.1 of the permanent magnet 15.

[0057] Both in the first embodiment according to FIG. 2 to FIG. 5 and also in the second embodiment according to FIG. 6 and FIG. 7, at least one surface edge 15b directly connecting the front end wall 15.3, the rear end wall 15.4, the leading side wall 15.5 and/or the trailing side wall 15.6 to the outer surface 15.1 in each case, in particular the surface edge 15b directly connecting the front end wall 15.3 and the rear end wall 15.4 to the outer surface 15.1 in each case is provided with an additional bevel 19b.

[0058] In the first embodiment according to FIG. 2 to FIG. 5, the base edges 15c, which in each case directly connect the front end wall 15.3, the rear end wall 15.4, the leading side wall 15.5 or the trailing side wall 15.6 to the base area 15.2 of the permanent magnet 15 pointing

[0059] in the direction of the magnet carrier 14, each indicate a further bevel 19c.

[0060] The cross-sectional representation according to FIG. 5 shows how the injection-molded plastic material of the plastic cage 17 encompasses the bevels 19 and 19c of the permanent magnets 15 in a form-fit manner in accordance with the first embodiment, in order to hold the permanent magnets 15 on the magnet carrier 14.

[0061] In the second embodiment according to FIG. 6 and FIG. 7, the permanent magnets 15 are firstly embodied in terms of design similarly to the first embodiment according to FIG. 2 to FIG. 5. Furthermore, the permanent magnets 15 of the second embodiment also have stepped surface edges 15d.

[0062] Therefore at least one surface edge 15d directly connecting the front end wall 15.3, the rear end wall 15.4, the leading side wall 15.5 and/or the trailing side wall 15.6 to the outer surface 15.1 in each case, in particular exclusively only the surface edges 15d directly connecting the leading side wall 15.5 and the trailing side wall 15.6 to the outer surface 15.1 in each case are embodied stepped.

[0063] The stepped surface edge 15d is formed by a recess 22, which has a width in the axial cross-section of the permanent magnet which amounts to between 10% and 15%, in particular 12% or 13% of the overall width of the permanent magnet. In the axial cross-section of the permanent magnet, the stepped surface edge formed by a recess has a minimal height of at least 0.5 millimeters, in particular at least 0.6 millimeters.

[0064] In the second embodiment as well, the at least one base edge 15c directly connecting the front end wall 15.3, the rear end wall 15.4, the leading side wall 15.5 and/or the trailing side 15.6 to the base area 15.2 of the permanent magnet 15 pointing in the direction of the magnet carrier 14 in each case is provided with the further bevel 19c.

[0065] The cross-sectional representation according to FIG. 7 shows how the injection-molded plastic material of the plastic cage 17 encompasses the bevels 19 and 19c and the stepped recesses 22 of the permanent magnets 15 in a form-fit manner according to the second embodiment, in order to hold the permanent magnets 15 on the magnet carrier 14.

[0066] In the third embodiment according to FIG. 8, each permanent magnet 15 has a cross-sectionally circular arc-shaped base area 15.2 pointing in the direction of the magnet carrier 14, and the magnet carrier 14 has a circular cross-section.

LIST OF REFERENCE CHARACTERS

[0067] 1 Pump [0068] 2 Pump housing [0069] 3 Pump wheel [0070] 4 Blades [0071] 5 Inlet opening [0072] 6 Outlet opening [0073] 7 Motor shaft [0074] 7a Front shaft end [0075] 8 Drive motor [0076] 9 Motor housing [0077] 10 Stator winding [0078] 11 Bearing [0079] 12 Annular gap [0080] 13 Rotor [0081] 14 Magnet carrier [0082] 14.1 Lateral area [0083] 15 Permanent magnets [0084] 15.1 Outer surface [0085] 15.2 Base area [0086] 15.3 Front end face [0087] 15.4 Rear end face [0088] 15.5 Leading side wall [0089] 15.6 Trailing side wall [0090] 15a Side edges [0091] 15b, d Surface edge [0092] 15c Base edges [0093] 16 Wet area [0094] 17 Plastic cage [0095] 18 Knurling [0096] 19 Bevel [0097] 19b Additional bevel [0098] 19c Further bevel [0099] 20 Hub [0100] 20.1 Inner lateral wall [0101] 21 Ribs [0102] 22 Recess