Electronically commutated motor for a liquid pump

Abstract

The invention relates to an electronically commutated motor (1) for a liquid pump, in particular a water pump, having a pump head (2) with a suction port (3) and a pressure port (4). The electronically commutated motor comprises a permanent magnet rotor (5) which is secured to a shaft (6), said shaft (6) being mounted within two bearings (7) and being operatively connected to a pump impeller (8), and a stator (9) having a winding (10) and at least one insulating element on which the winding (10) is secured, wherein the stator (9) has a completely circumferential encapsulation (11) which forms a containment shell (12) in an inner region of the encapsulation (11) in order to separate the permanent magnet rotor (5) from the stator (9) in a liquid-tight manner, a bearing (7) is molded into the containment shell base (13), a bearing plate (14) comprises a drive-side bearing (7) and is provided between the pump head (2) and the encapsulation (11), the bearing plate (14) has a first number of throughflow openings (15) for a downward flow and a second number of throughflow openings (16) for an upward flow, and the bearing plate (14) has, on the lower face (17) facing the encapsulation (11), a plurality of holding elements (18) which correspond to recesses (19) in the encapsulation (11). The encapsulation (11) has a receiving space (20) for electronics (21), and the receiving space (20) of the encapsulation (11) is closed by a cover (22).

Description

[0001] Title: Electronically commutated motor for a liquid pump

[0002] DESCRIPTION

[0003] The invention relates to an electronically commutated motor for a liquid pump according to the preamble of claim 1.

[0004] In a typical electronically commutated motor for a liquid pump, the stator and rotor are separated by a containment shell or a can. This prevents the coolant from entering the stator. However, the disadvantage of a containment shell is that the stagnant water, which is set in motion by the rotating rotor, has no urge to flow out of the containment shell into the cooling water area.

[0005] The object of the invention is to provide an electronically commutated motor for a liquid pump in which a constant exchange of the stagnant liquid with the flowing cooling circuit is promoted and thereby improves the cooling and flow around the rotor and stator.

[0006] This object is achieved by the features according to claim 1. An electronically commutated motor for a liquid pump, in particular a water pump, with a pump head having a suction and pressure connection, comprising a permanent magnet rotor which is fastened to a shaft, wherein the shaft is mounted within two bearings and is operatively connected to a pump impeller, a stator with a winding and at least one insulating element on which the winding is fastened, wherein the stator has a full-circumferential overmolding which forms a containment shell in an inner region of the overmolding in order to separate the permanent magnet rotor from the stator in a liquid-tight manner, wherein a bearing is injected into a containment shell base, wherein a bearing plate comprises a drive-side bearing and is arranged between the pump head and the overmolding,The bearing plate has a first number of through-flow openings for downward flow and a second number of through-flow openings for upward flow. The bearing plate has a plurality of retaining elements on the underside facing the overmolding, which correspond to recesses in the overmolding. The overmolding has a receiving space for electronics, and the receiving space of the overmolding is closed by a cover. The bearing plate separates the pump area from the stator and permanent magnet rotor. The stator with the winding is positioned at least one point on the circumference of a stator laminated core and axially on the insulating element during the injection molding process.

[0007] In an advantageous embodiment, the first number of flow openings has a downward bevel and is designed to be greater and / or smaller and / or identical in length (L) to the length (L) of the second number of flow openings. The bevel of the first number of flow openings is designed to be downward at an angle, preferably 45 degrees. However, other technically feasible angles are also conceivable. Downward here means that the bevel runs from top to bottom in the bearing plate. The downward bevel in the first number of flow openings increases the surface area of ​​the flow openings and reduces the velocity of the liquid. The first number of flow openings are preferably designed to be greater in length (L) than the second number of flow openings.As the pump impeller rotates, pressure is created underneath it, which directs the liquid downwards through the first number of flow openings towards the containment shell and permanent magnet rotor.

[0008] It is advantageous that the second number of flow openings has an upward slope and is designed to be greater and / or smaller and / or identical in length (L) to the length (L) of the first number of flow openings. The slope of the second number of flow openings is designed at an upward angle, preferably 45 degrees. However, other technically feasible angles are also conceivable. Upward here means that the slope runs from bottom to top in the bearing plate. The upward slope in the second number of flow openings enlarges the surface area of ​​the flow openings and reduces the speed of the fluid. The rotation of the permanent magnet rotor, which is attached to the shaft, guides the fluid of the cooling circuit and the fluid in the containment shell upwards through the second number of flow openings.The second number of flow openings is preferably smaller in length (L) than the first number of flow openings.

[0009] In a further embodiment, a partially circumferential guide wall is formed on the underside of the bearing plate at the level of the second number of flow openings. The fluid flowing through the liquid pump in the cooling circuit, reaching the underside of the bearing plate, is guided through the guide wall to the second number of flow openings and flows through the second number of flow openings back under the pump impeller into the cooling circuit. The guide wall on the bearing plate thus prevents the fluid from flowing directly from the first number of flow openings to the second number of flow openings.

[0010] It is also advantageous for the overmolding to have notches on one end between the overmolded stator teeth and a baffle in the area of ​​the containment shell. The fluid flows, preferably clockwise, over the notches, cooling the stator winding and being guided through the baffle into the containment shell. Slight curvatures on the edge of the baffle cause the fluid to swirl downward and then circulate through the permanent magnet rotor and along the outside of the permanent magnet rotor. The permanent magnet rotor can contain fluid channels so that the fluid can flow through the permanent magnet rotor. Alternatively, at least one centering pin can be formed on the baffle, which serves to radially fix the bearing plate to the overmolding.

[0011] In a further embodiment, the containment shell base has bearing spokes that are designed with upward or downward bevels. At least one bearing spoke is designed so that the fluid is directed downwards to a cooling plate for cooling the electronics and is then directed upwards into the containment shell by at least one bearing spoke. Since the pressure is applied from above, the fluid flows upwards through the permanent magnet rotor, creating a fluid flow down to below the pump impeller. The bearing spokes in the containment shell base advantageously provide an increased fluid flow at the cooling plate to the electronics.

[0012] According to a further embodiment, a cooling plate is arranged between a circuit board and the overmolding. The cooling plate and the bearing plate are preferably screwed to the overmolding. However, another fastening method known to those skilled in the art is also possible. The cooling plate allows the heat generated by the electronics to be dissipated to the liquid more efficiently. The cooling plate is preferably made of a heat-dissipating material.

[0013] The cooling plate's radial circumference is advantageous because it has multiple contours that correspond to mating contours on the overmolding, and a support point for the shaft in its center. These multiple contours allow the cooling plate to be attached to the overmolding in a space-saving manner.

[0014] In a further embodiment, a thrust washer is arranged on an axial end face of the permanent magnet rotor or in a laminated core of the permanent magnet rotor. Furthermore, a perforation element, which is designed in the shape of a disc or pot, is arranged between the base of the containment shell and the permanent magnet rotor. A fluid flow is generated via the perforation element, in which, like a vegetable grater, some fluid is "scraped off" with each rotation of the permanent magnet rotor and fed into the permanent magnet rotor. This creates a vacuum below the permanent magnet rotor, which ensures that fluid is sucked in from above in the fluid gap on the outer diameter of the permanent magnet rotor. This creates a speed-dependent fluid flow that flows upwards through the permanent magnet rotor towards the pump impeller, outwards along the permanent magnet rotor and downwards into the containment shell.Through a circumferential edge on the perforation element, this liquid flow is brought down to the cooling plate, resulting in an active liquid flow.

[0015] According to a further embodiment, the perforation element is formed by the last axial permanent magnet rotor lamination. This eliminates the need for an additional component as a perforation element.

[0016] The features and advantages of the electronically commutated motor for a liquid pump of the present invention are explained in more detail below using exemplary embodiments with reference to the drawings.

[0017] Fig. 1 is an exemplary overview of an electronically commutated motor for a liquid pump according to an embodiment,

[0018] Fig. 2 is a plan view of the top of the bearing plate;

[0019] Fig. 3 is a plan view of the underside of the bearing plate;

[0020] Fig. 4 is a schematic representation of the first and second number of flow openings in the bearing plate;

[0021] Fig. 5 shows a representation of the stator with a full overmolding;

[0022] Fig. 6 is a plan view of the underside of the overmold;

[0023] Fig. 7 is a plan view of the underside of the cooling plate;

[0024] Fig. 8 is a top view of the cooling plate.

[0025] Fig. 9 shows a representation of a perforation element. In Fig.1 shows an exemplary overview of an electronically commutated motor (1) for a liquid pump, in particular a water pump, with a pump head (2) with a suction (3) and a pressure port (4), comprising a permanent magnet rotor (5) which is fastened to a shaft (6), wherein the shaft (6) is mounted within two bearings (7) and is operatively connected to a pump impeller (8), a stator (9) with a winding (10) and at least one insulating element on which the winding (10) is fastened, wherein the stator (9) has a full-circumferential overmolding (11) which forms a containment shell (12) in an inner region of the overmolding (11) in order to separate the permanent magnet rotor (5) from the stator (9) in a liquid-tight manner, wherein a bearing (7) is injected into a containment shell base (13), wherein a bearing plate (14) forms a drive-side bearing (7) and is arranged between the pump head (2) and the overmolding (11).A cooling plate (31) is arranged between a circuit board (32) and the overmolding (11). A thrust washer (36) is arranged on an axial end face of the permanent magnet rotor (5) or in the laminated core (37) of the permanent magnet rotor (5). In addition, a perforation element (38) which is designed in the shape of a disc or pot can be arranged between the containment shell base (13) and the permanent magnet rotor (5). The perforation element (38) can also be formed by the last axial permanent magnet rotor sheet. The overmolding (11) has a receiving space (20) for electronics (21), and the receiving space (20) of the overmolding (11) is closed by a cover (22).

[0026] Fig. 2 shows a plan view of the upper side of the bearing plate (14), which has a first number of flow openings (15) for downward flow and a second number of flow openings (16) for upward flow. The first number of flow openings (15) has a downward bevel (23) and is designed to be longer and / or smaller and / or identical in length (L) to the length (L) of the second number of flow openings (16). The second number of flow openings (16) has an upward bevel (24) and is designed to be longer and / or smaller and / or identical in length (L) to the length (L) of the first number of flow openings (15). Fig. 3 shows a plan view of the underside of the bearing plate (14). The underside (17) of the bearing plate (14) faces the overmolding (11) and has a plurality of holding elements (18) which correspond to recesses (19) in the overmolding (11).The first number of flow openings (15) has a downward bevel (23) and is designed to be greater and / or smaller and / or identical in length (L) to the length (L) of the second number of flow openings (16). The second number of flow openings (16) has an upward bevel (24) and is designed to be greater and / or smaller in length (L) and / or identical in length (L) to the length (L) of the first number of flow openings (15). A partially circumferential guide wall (25) is formed on the underside (17) of the bearing plate (14) at the level of the second number of flow openings (16).

[0027] Fig. 4 shows a schematic representation of the first and second number of flow openings in the bearing plate (14). The first number of flow openings (15) has a downward bevel (23) and is designed to be longer and / or shorter and / or identical in length (L) to the length (L) of the second number of flow openings (16). The second number of flow openings (16) has an upward bevel (24) and is designed to be longer and / or shorter and / or identical in length (L) to the length (L) of the first number of flow openings (15).

[0028] Fig. 5 shows a representation of the stator (9) with a fully circumferential overmolding (11), which forms a containment shell (12) in an inner region of the overmolding (11) in order to separate the permanent magnet rotor (5) (not shown here) from the stator (9) in a liquid-tight manner. The overmolding (11) has notches (28) on an end face (26) between the overmolded stator teeth (27) and a baffle wall (29) in the region of the containment shell (12). At least one inspection hole (39) is formed on the overmolding (11), by means of which the overmolding (11) is fastened to the pump head (2). In addition, a receptacle for a plug can be formed on the overmolding (11). Fig. 6 shows a plan view of the underside of the overmolding (11). The can base (13) has bearing spokes (30) which are formed with bevels upwards (24) or downwards (23).On the underside of the overmolding (11) counter contours (34) are formed, which correspond to several contours (33) (not shown here) of the cooling plate (31) (not shown here).

[0029] Fig. 7 shows a plan view of the underside of the cooling plate (31). The cooling plate (31) has several contours (33) on its radial circumference, which correspond to counter-contours (34) on the overmolding (11) and has a support point (35) for the shaft (6) in its center.

[0030] Fig. 8 shows a top view of the cooling plate (31). The cooling plate (31) is arranged between a circuit board (32) and the overmolding (11). Furthermore, the cooling plate (31) has several contours (33) on its radial circumference, which correspond to counter-contours (34) on the overmolding (11). At its center, the cooling plate (31) has a support point (35) for the shaft (6).

[0031] Fig. 9 shows a representation of a perforation element (38). The perforation element (38) is arranged between the can base (13) (see Fig. 1 ) and the permanent magnet rotor (5) (see Fig. 1 ) and is disk- or pot-shaped. A liquid flow is generated via the perforation element (38) in which, like in a vegetable grater, with each rotation of the permanent magnet rotor some liquid is “scraped off” and guided into the permanent magnet rotor. The “scraping off” of the liquid takes place in the perforation element (38) via at least one hole (4). The coarser the at least one hole (40) is, the more liquid is “scraped off” and vice versa for a finer hole (40). This creates a negative pressure below the permanent magnet rotor (5) (see Fig. 1 ), which ensures that liquid is sucked in from above in the liquid gap on the outer diameter of the permanent magnet rotor (5).This creates a speed-dependent fluid flow that flows through the permanent magnet rotor (5) upwards towards the pump impeller (8) (see Fig. 1 ), outwards along the permanent magnet rotor (5) and downwards into the containment shell (13). A circumferential edge (41 ) on the perforation element (38) directs this fluid flow downwards to the cooling plate (31 ), resulting in an active fluid flow. In an alternative embodiment, the perforation element (38) can be formed by the last axial permanent magnet rotor sheet. This makes it possible to eliminate the need for an additional component as the perforation element (38). In an exemplary embodiment, the perforation element (38) has a shaft passage (42) around which a plurality of holes (40) are arranged concentrically. The holes (40) are advantageously aligned such that they run essentially in alignment with flow channels in the permanent magnet rotor (5).The peripheral edge (41) adjoins the permanent magnet rotor (5) or encloses it in the first permanent magnet rotor laminations. A material elevation (43) is formed in the shaft passage (42), which engages a recess in the permanent magnet rotor (see Fig. 1).

[0032] List of reference symbols:

[0033] 1 . Electronically commutated motor

[0034] 2. Pump head

[0035] 3. Suction nozzle

[0036] 4. Pressure nozzle

[0037] 5. Permanent magnet rotor

[0038] 6th wave

[0039] 7. Camp

[0040] 8. Pump impeller

[0041] 9. Stator

[0042] 10. Winding

[0043] 11. Overmolding

[0044] 12. Containment shell

[0045] 13. Containment shell base

[0046] 14. Bearing plate

[0047] 15. First number of flow openings

[0048] 16. Second number of flow openings

[0049] 17. Bottom

[0050] 18. Holding elements

[0051] 19. Recesses

[0052] 20. Recording room

[0053] 21. Electronics

[0054] 22. Lid

[0055] 23. Bevel downwards

[0056] 24. Bevel upwards

[0057] 25. Guide wall

[0058] 26. Front side

[0059] 27. Stator teeth

[0060] 28. Notches

[0061] 29. Baffle

[0062] 30. Bearing spokes

Claims

PATENT CLAIMS Electronically commutated motor (1) for a liquid pump, in particular a water pump, with a pump head (2) with a suction (3) and a pressure port (4), comprising a permanent magnet rotor (5) which is fastened to a shaft (6), wherein the shaft (6) is mounted within two bearings (7) and is operatively connected to a pump impeller (8), a stator (9) with a winding (10) and at least one insulating element on which the winding (10) is fastened, wherein the stator (9) has a fully circumferential overmolding (11) which forms a containment shell (12) in an inner region of the overmolding (11) in order to separate the permanent magnet rotor (5) from the stator (9) in a liquid-tight manner, wherein a bearing (7) is injected into a containment shell base (13), wherein a bearing plate (14) comprises a drive-side bearing (7) and is arranged between the pump head (2) and the overmolding (11),wherein the bearing plate (14) has a first number of flow openings (15) for a downward flow and a second number of flow openings (16) for an upward flow and wherein the bearing plate (14) on the underside, (17) facing the overmolding (11), a plurality of holding elements (18) which correspond to recesses (19) in the overmolding (11), wherein the overmolding (11) has a receiving space (20) for an electronics (21) and wherein the receiving space (20) of the overmolding (11) is closed by a cover (22).

2. Electronically commutated motor according to claim 1, wherein the first number of flow openings (15) has a downward bevel (23) and is designed to be greater and / or smaller and / or identical in length (L) to the length (L) of the second number of flow openings (16). Electronically commutated motor according to claim 1, wherein the second number of flow openings (16) has an upward bevel (24) and is designed to be greater and / or smaller and / or identical in length (L) to the length (L) of the first number of flow openings (15). Electronically commutated motor according to claim 1, wherein a partially circumferential guide wall (25) is formed on the underside (17) of the bearing plate (14) at the level of the second number of flow openings (16).Electronically commutated motor according to claim 1, wherein the overmolding (11) has notches (28) on an end face (26) between the overmolded stator teeth (27) and a baffle wall (29) in the region of the containment shell (12). Electronically commutated motor according to claim 1, wherein the containment shell base (13) has bearing spokes (30) formed with upward (24) or downward (23) bevels. Electronically commutated motor according to claim 1, wherein a cooling plate (31) is arranged between a circuit board (32) and the overmolding (11). Electronically commutated motor according to claim 7, wherein the cooling plate (31) has a plurality of contours (33) on its radial circumference, which correspond to counter contours (34) on the overmolding (11) and has a support point (35) for the shaft (6) in its center.

9. Electronically commutated motor according to claim 1, wherein a thrust washer (36) is arranged on an axial end face of the permanent magnet rotor (5) or in a laminated core (37) of the permanent magnet rotor (5).

10. Electronically commutated motor according to claim 1, wherein between the can base (13) and the permanent magnet rotor (5) a perforation element (38) is arranged, which is disc-shaped or pot-shaped.

11. Electronically commutated motor according to claim 10, wherein the perforation element (38) is formed by the last axial rotor lamination.

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