Electronically commutated fluid pump with efficient heat dissipation from the electronic components and the stator winding

Abstract

Electronically commutated fluid pump (1), comprising: a pump head (2) with a pump impeller (3), a suction nozzle (4) and a pressure nozzle (5); a pump housing (6) which is connected on one side to the pump head (2) and on the other side to an electronics housing (7) in which electronics (8) are arranged; a permanent magnet rotor (9) mounted on a motor shaft (10); and a stator (11) arranged around the permanent magnet rotor (9) and having insulating material bodies (12) on its axial end faces; wherein the stator (11) is surrounded by an overmolding (13) made of a non-magnetic material and wherein the overmolding (13) forms a bearing wheel (20) in a base region (19), wherein the bearing wheel (20) forms a plurality of fluid openings (21) and a first bearing seat (22) for the motor shaft (10), wherein the stator (11) is formed from stator laminations (14) and is overmolding at least in regions, wherein the stator laminations (14) are not overmolding on their radial outer surface and are at least partially exposed, wherein the overmolding (13) forms at least part of the pump housing (6). wherein a support plate (23) is formed between the pump head (2) and the overmolding (13), wherein the support plate (23) forms a plurality of fluid openings (24) and a second bearing seat (25) for the motor shaft (10), and wherein the support plate (23) at least partially forms the pump housing (6) by means of an extended edge region (26).

Description

The invention relates to an electronically commutated fluid pump according to the preamble of claim 1.In known fluid pumps of the aforementioned type, the problem of efficient heat dissipation or heat dissipation of the electronic components and the stator winding often arises. In some fluid pumps, a containment shell is used, wherein a rotor is mounted in a medium and the containment shell separates a stator from the rotor in a medium-tight manner. During the heat dissipation via a split pot, the heat of the electronic components and of the stator winding is dissipated only into the medium itself. Especially in the case of fluid pumps with higher performance classes, such heat dissipation via the containment shell alone is often not sufficient or expedient.DE 10 2019 115 778 A1 discloses a pump for a liquid circuit in a vehicle. The pump includes a pump chamber having an impeller and a motor chamber having a stator and a rotor. The stator is cast into an electronics housing and completely enclosed. The fluid runs along this stator injection molding and is discharged via a through opening into the inner region of the stator along the rotor in the direction of the pressure output. Disadvantages are the non-optimum heat dissipation of the components of the pump and the more complex, fully surrounding extrusion coating of the stator, which additionally restricts advantageous heating.EP 1 503 083 A1 discloses an electric pump for cooling circuits with an injection molding which essentially forms the housing of the pump and an insert which is integrally formed in the interior and through which the fluid is conducted along the electronics. A disadvantage is the non-optimum heat dissipation of the stator, which is completely surrounded by an overmoulding, as a result of which the heat of the stator cannot be dissipated well. It is also disadvantageous in this application that when fluid is used, the electronics can be damaged, since there is direct contact without shielding.It is an object of the invention to propose an electronically commutated fluid pump with efficient heat dissipation from the electronic components and the stator winding. In addition, the number of components is to be reduced.This object is achieved by the features according to claim 1.An electronically commutated fluid pump according to the invention comprises: a pump head having a pump impeller, a suction connection piece and a pressure connection piece, a pump housing which is connected on one side to the pump head and on the other side to an electronics housing in which an electronics unit is arranged, a permanent magnet rotor which is mounted on a motor shaft, and a stator which is arranged around the permanent magnet rotor and has insulating material bodies on its axial end sides, wherein the stator is surrounded by an encapsulation made of a non-magnetic material.The overmolding forms a bearing wheel in a base region, wherein the bearing wheel forms a plurality of fluid openings and a first bearing seat for the motor shaft.This advantageously makes it possible to save on a bearing seat as an additional component. In the base region of the overmolding, screw-on eyes and a double wall for a seal are also formed. The bottom region serves as a bearing surface for the pump housing. In the base region, the medium can collect through the fluid openings and support the heat dissipation of the electronics. The first bearing seat is a slide bearing or receives a slide bearing. The bearing wheel and / or the bearing seat are preferably formed integrally with the insert molding. However, it would also be conceivable for the bearing wheel and / or bearing seat to be injection-molded separately or to be provided on the injection-molded part in another manner acting in the same way. Alternatively, the first bearing seat in the base region of the overmolding can also be omitted if no bearing seat is required.The stator is formed from stator laminations and is encapsulated by injection molding at least in regions, wherein the stator laminations are at least partially exposed. The radial outer surface of the stator laminations is not co-encapsulated here and thus remains exposed. Preferably after the winding and contacting, the stator laminations are encapsulated with non-magnetic material in the region of wound-around pole shoes. The non-magnetic material may be thermoplastic or thermosetting plastic.The overmolding forms at least a part of the pump housing. This makes it possible to save an additional housing part.A carrier plate is formed between the pump head and the overmolding, wherein the carrier plate forms a plurality of fluid openings and a second bearing seat for the motor shaft. The second bearing seat is a slide bearing or receives a slide bearing.The first and / or second bearing seat can, however, also be or receive another bearing known to the person skilled in the art.The carrier plate at least partially forms the pump housing by an extended edge region. An extended edge region is to be understood as extending in the axial direction and ending with the overmolding. In other words, the pump housing consists of two parts, namely the injection molding and the carrier plate with the extended edge region.It is advantageous here that the heat dissipation from the electronic components and the stator winding, due to the configuration of the stator according to the invention, takes place not only into the medium, but also to the environment, for example to the ambient air. In addition, a prefabricated containment shell can be dispensed with, which facilitates the manufacture and the assembly of the fluid pump by reducing the component.In a preferred embodiment, the motor shaft is designed as a hollow shaft. A hollow shaft has the advantage that an additional flow path of the medium can be guided through the hollow shaft and the heat dissipation additionally takes place or can take place through the flow path in the hollow shaft. However, commercially available solid shafts known to the skilled person are also conceivable. The motor shaft is assembled by press fitting or other methods known to those skilled in the art.At least one insulating body is injection-molded or mounted on the end faces of the stator or of the stator laminations and the stator winding is contacted on the at least one insulating body. After winding and contacting, the stator is surrounded over its entire circumference with a non-magnetic material, for example by a common injection molding method. The non-magnetic material may be thermoplastic or thermosetting plastic.Alternatively, the stator or the stator laminations can also be injection-molded prior to winding. After the winding and contacting, an additional injection molding of the stator with non-magnetic material then takes place.Alternatively, the stator laminations can also be injection-molded at least in regions before winding and contacting and can be provided at least in regions with a second injection-molding following winding and contacting.In a further embodiment, the overmolding forms a split pot on an inner region of the stator or comprises the latter. Alternatively, the overmolding can be effected only partially on the outer surface of the stator and a prefabricated containment shell can be used. The split cup formed by the overmolding creates a media-tight enclosure of the stator.Particularly advantageously, a plurality of axially parallel grooves are formed distributed on the outer periphery of the overmolding. The grooves on the outer circumference can protrude completely and / or partially as far as a base region of the overmolding. For example, on the outer periphery, one or more grooves can protrude as far as the base region of the overmolding and one or more further grooves can only partially protrude as far as the base region of the overmolding. The grooves can also optionally be formed on the inner region of the overmolding. Because of the advantageous pumping effect, the grooves can also be helical (helical), but can also be helical, coaxial or concentric. Other embodiments for the grooves known to the skilled person are also possible.The grooves on the outer surface and / or inner surface of the encapsulation serve for heat dissipation from the electronic components and the stator winding. The grooves on the outer surface and / or inner surface of the injection molding improve the inflow and outflow of the medium. In addition, the grooves on the outer surface of the overmolding serve as a means of preventing the overmolding from rotating and a carrier plate with an extended edge. The grooves claw in counter-contours of the extended edge of the carrier plate.In a development, the permanent magnet rotor comprises at least one laminated core or is formed from at least one laminated core, wherein the at least one laminated core has fluid channels running axially parallel. The permanent magnet rotor is surrounded by the injection molding and is surrounded by a medium. The axially parallel fluid channels in the at least one laminated core additionally flush through the permanent magnet rotor.According to a further embodiment, a separating plate is provided between the base region of the overmolding and the electronics (printed circuit board). The separating plate is preferably made of aluminum, but other materials are also conceivable which ensure good heat dissipation. The heat dissipation from the electronic components takes place via the circulating medium on the separating plate. Preferably, the electronics are mounted directly and without any spacing on or on one side of the separating plate in order to ensure the greatest possible thermal contact. Optionally, the separating plate can also be attached to the electronics with a spacing, in which a heat-conducting medium (e.g. heat-conducting paste, heat-conducting foil, etc.) is used. The separating plate separates the dry region from the wet region of the fluid pump.In a further embodiment, a slide bearing is provided in the carrier plate, wherein the slide bearing has at least one hydrodynamic groove. This groove serves as a lubrication gap for the bearing.In a further embodiment, a tolerance ring is arranged around the overmolding or the stator. Alternatively, the tolerance ring can also be arranged around the stator laminations. This is formed from spring steel. It is possible in principle for the tolerance ring to correspond to the grooves on the outer periphery of the injection molding. The tolerance ring also serves to prevent rotation between the overmolding and the carrier plate.In a further embodiment, the fluid pump comprises at least one flow path. In the fluid pump according to the invention, two flow paths, namely a primary flow path and a secondary flow path, are preferably formed. The primary flow path runs, on the one hand, through the split pot formed in the inner region of the overmolding, washes around the rotor, exits at the base region of the overmolding through the fluid channels in the bearing wheel and is conveyed upward through the hollow shaft by pressure at the hollow shaft. The medium accumulated in the base region of the overmolding is transported through the hollow shaft, as a result of which additional heat dissipation from the electronic components and the stator winding takes place. As a result, the heat of the electronics is absorbed via the primary flow path on the separating plate and dissipated to the medium and the environment. On the other hand, the primary flow path also runs between the carrier plate and the overmolding, as a result of which the heat of the stator winding is dissipated to the medium and the environment. The secondary flow path is defined by the axially parallel fluid channels in the laminated core of the permanent magnet rotor. The medium flushes through the permanent magnet rotor and is conveyed upwards through the hollow shaft by pressure at the hollow shaft. If a solid shaft is used, the primary flow path runs through the secondary flow path, that is to say the medium is conveyed upward through the fluid channels of the permanent magnet rotor. Alternatively, the medium can also be conveyed upward in a fluid channel between the laminated core and the solid shaft in addition to the fluid channels in the laminated core.The electronically commutated fluid pump is preferably designed as a coolant pump, in particular a centrifugal pump.List of reference characters1 Fluid pump 2 Pump head 3 Pump impeller 4 Suction connection 5 Pressure connection 6 Pump housing 7 Electronics housing 8 Electronics 9 Permanent magnet rotor 10 Motor shaft 11 Stator 12 Insulating material body 13 Injection molding 14 Stator laminations 15 Inner region 16 Containment shell 17 Outer periphery 18 Grooves 19 Base region 20 Bearing wheel 21 Fluid openings Bearing wheel 22 First bearing seat 23 Carrier plate 24 Fluid openings Carrier plate 25 Second bearing seat 26 Edge region 27 Laminated core 28 Fluid channels 29 Separating plate 30 Sliding bearing 31 Tolerance ringThe invention is explained in more detail below on the basis of exemplary embodiments with reference to the appended drawings. The following are shown: FIG. 1 shows a longitudinal sectional view through an electronically commutated fluid pump according to the invention according to a preferred embodiment; FIG. 2 shows a top view of an overmolding according to FIG. 1 ; FIG. 3 is a bottom view of an overmolding according to FIG. 2 ; FIG. 4 shows a plan view of a carrier plate according to an embodiment.FIG. 1 shows a longitudinal sectional view through an electronically commutated fluid pump (1) according to the invention according to a preferred embodiment, comprising a pump head (2) with a pump impeller (3), a suction connection piece (4) and a pressure connection piece (5), a pump housing (6) which is connected on one side to the pump head (2) and on the other side to an electronics housing (7) in which the electronics (8) are arranged, a permanent magnet rotor (9) which is mounted on a motor shaft (10), and a stator (11) which is arranged around the permanent magnet rotor (9) and has insulating material bodies (12) on its axial end sides, wherein the stator (11) is surrounded by an encapsulation (13) made of a non-magnetic material. In this case, at least one insulating body (12) is injection-molded onto or mounted on the end faces of the stator (11) or of the stator laminations (14), and the stator winding is in contact with the at least one insulating body (12). After winding and contacting, the stator ( 12) is surrounded over its entire circumference or alternatively at least partially with a non-magnetic material, for example by a common injection molding method. A plug is formed or mounted on the electronics housing (7). The motor shaft (10) is designed as a hollow shaft. However, other commercially available solid shafts known to the skilled person are also conceivable. The stator ( 11) is formed from stator laminations ( 14) which are completely encapsulated by the non-magnetic material by injection molding. Alternatively, however, it is also possible to not completely spray the stator laminations ( 14) with the non-magnetic material. The overmolding ( 13) forms part of the pump housing ( 6). Between the pump head (2) and the overmolding (13), a carrier plate (23) is formed, which at least partially forms the pump housing (6), in particular by an extended edge region (26). In the support plate (23), a slide bearing (30) is provided which has a hydrodynamic groove. A separating plate (29) is provided between the overmolding (13) and the electronics housing (7). The separating plate ( 29) is formed from a preferably metallic material, in order to improve efficient heat dissipation of the electronic components. The separating plate ( 29) can, however, also be formed from plastic. The permanent magnet rotor (9) comprises at least one laminated core (27) or is formed from at least one laminated core (27). The at least one laminated core (27) has fluid channels (28) running parallel to the axis, through which the laminated core (27) is flushed with medium and flushed within the encapsulation (13).FIG. 2 shows a top view of an overmolding ( 13) according to FIG. 1 The overmolding ( 13) made of non-magnetic material forms the stator ( 11) with the overmolded stator laminations ( 14). At an inner region (15) of the stator (11), the injection molding (13) comprises or forms a split pot (16). By means of the injection-molding according to the invention of the stator laminations (14), a split pot (16) can be formed in the inner region (15) of the stator (11). As a result, a prefabricated containment shell as an individual component can be dispensed with and the number of components can be reduced, which in turn saves costs. Alternatively, the stator (11) is encapsulated by injection molding at least in regions, wherein the stator laminations (14) are at least partially exposed. Preferably after the winding and contacting, the stator laminations ( 14) are encapsulated with non-magnetic material in the region of the wound-around pole shoes. The non-magnetic material may be thermoplastic or thermosetting plastic. The radial outer surface of the stator laminations ( 14) is not co-encapsulated here and thus remains exposed. As an alternative to the containment shell (16) formed by the encapsulation (13), a prefabricated containment shell can also be inserted into the inner region of the encapsulation (13) if the stator (11) is only partially encapsulated by injection molding. On an outer periphery (17) of the overmolding (13), a plurality of axially parallel grooves (18) are formed in a distributed manner. The grooves (18) can protrude on the outer periphery (17) completely and / or partially as far as a base region (19). For example, on the outer periphery (17), one or more grooves (18) can protrude as far as the base region (19) and one or more further grooves (18) can only partially protrude as far as the base region (19). The grooves ( 18) can also optionally be formed on the inner region ( 15) of the overmolding ( 13). Because of the advantageous pumping effect, the grooves (18) can also be helical (helical), but also helical, coaxial or concentric. Other embodiments known to the skilled person for the grooves ( 18) are also possible. In the base region (19) of the overmolding (13), a bearing wheel (20) is formed, which forms a plurality of fluid openings (21) and a first bearing seat (22) for the motor shaft (10). This advantageously makes it possible to save on a bearing seat as an additional component. In the base region (19), screw-on eyes and a double wall for a seal are also formed. The bottom region (19) serves as a bearing surface for the pump housing (6). The medium can collect in the base region (19) through the fluid openings (21) and support the heat dissipation of the electronics (8). The first bearing seat ( 22) is a slide bearing or receives a slide bearing. The bearing wheel ( 20) and / or the bearing seat ( 22) are preferably formed integrally with the overmolding ( 13). However, it would also be conceivable for the bearing wheel ( 20) and / or bearing seat ( 22) to be injection-molded separately or to be provided on the injection-molded part ( 13) in another manner acting in the same way. On the outer periphery ( 17) of the overmolding ( 13) or on the stator ( 11), a tolerance ring ( 31) is arranged, which is formed from spring steel. Alternatively, the tolerance ring ( 31) can also be arranged around the stator laminations ( 14). It is possible in principle for the tolerance ring ( 31) to correspond to the grooves ( 18) on the outer periphery ( 17) of the overmolding ( 13).FIG. 3 shows a bottom view of an overmolding ( 13) according to FIG. 2 ; at an inner region ( 15) of the stator ( 11), the overmolding ( 13) comprises or forms a containment shell ( 16). On an outer periphery (17) of the overmolding (13), a plurality of axially parallel grooves (18) are formed in a distributed manner. In the base region (19) of the overmolding (13), a bearing wheel (20) is formed, which forms a plurality of fluid openings (21) and a first bearing seat (22) for the motor shaft (10). This advantageously makes it possible to save on a bearing seat as an additional component. In the base region (19), screw-on eyes and a double wall for a seal are also formed. The bottom region (19) serves as a bearing surface for the pump housing (6). The medium can collect in the base region (19) through the fluid openings (21) and support the heat dissipation of the electronics (8). The first bearing seat ( 22) is a slide bearing or receives a slide bearing. On the outer periphery (17) of the overmolding (13) or the stator (11), a tolerance ring (31) is arranged, which is formed from spring steel and corresponds to the grooves (18) on the outer periphery (17) of the overmolding (13). The bottom region (19) serves as a bearing surface for the pump housing (6). In addition, in the base region ( 19), receiving contours for a separating plate ( 29) and receiving contours for connection parts of the electronics ( 8) are formed.FIG. 4 shows a top view of a carrier plate ( 23) according to an embodiment. The carrier plate (23) is formed between the pump head (2) and the injection molding (13) and forms a plurality of fluid openings (24) and a second bearing seat (25) for the motor shaft (10). The carrier plate (23) at least partially forms the pump housing (6), in particular by an extended edge region (26). In other words, the pump housing ( 6) consists of two parts, namely the injection molding ( 13) and the carrier plate ( 23) with the extended edge region ( 26). In the support plate (23), a slide bearing (30) (not shown here) is provided, which has at least one hydrodynamic groove. The second bearing seat ( 25) is a slide bearing or receives a slide bearing. The carrier plate ( 23) can be formed from a metallic or a thermoplastic or thermosetting material. However, other materials known to the skilled person are also conceivable for the carrier plate ( 23).

Claims

Electronically commutated fluid pump (1) comprising: a pump head (2) with a pump impeller (3), a suction connection piece (4) and a pressure connection piece (5); a pump housing (6) which is connected on one side to the pump head (2) and on the other side to an electronics housing (7) in which an electronics (8) is arranged; a permanent magnet rotor (9) which is mounted on a motor shaft (10); and a stator (11) which is arranged around the permanent magnet rotor (9) and has insulating material bodies (12) on its axial end sides; wherein the stator (11) is surrounded by an encapsulation (13) made of a non-magnetic material and wherein the encapsulation (13) forms a bearing wheel (20) in a base region (19), wherein the bearing wheel (20) forms a plurality of fluid openings (21) and a first bearing seat (22) for the motor shaft (10), wherein the stator (11) is formed from stator laminations (14) and is encapsulated by injection molding at least in regions, wherein the stator laminations (14) are not encapsulated by injection molding on their radial outer surface and are at least partially exposed, wherein the encapsulation (13) forms at least part of the pump housing (6), wherein a carrier plate (23) is formed between the pump head (2) and the encapsulation (13), wherein the carrier plate (23) forms a plurality of fluid openings (24) and a second bearing seat (25) for the motor shaft (10), and wherein the carrier plate (23) forms at least partially the pump housing (6) by an extended edge region (26).Electronically commutated fluid pump according to claim 1, wherein the motor shaft (10) is designed as a hollow shaft.Electronically commutated fluid pump according to Claim 1, wherein the encapsulation (13) comprises or forms a containment shell (16) at an inner region (15) of the stator (11).Electronically commutated fluid pump according to one of the preceding claims, wherein a plurality of axially parallel grooves (18) are formed distributed on the outer periphery (17) of the encapsulation (13).Electronically commutated fluid pump according to one of the preceding claims, wherein the permanent magnet rotor (9) comprises at least one laminated core (27) or is formed from at least one laminated core (27), wherein the at least one laminated core (27) has fluid channels (28) running axially parallel.Electronically commutated fluid pump according to one of the preceding claims, wherein a separating plate (29) is provided between the base region (19) of the overmolding (13) and the electronics (8).Electronically commutated fluid pump according to one of the preceding claims, wherein a sliding bearing (30) is provided in the carrier plate (23), wherein the sliding bearing has at least one hydrodynamic groove.Electronically commutated fluid pump according to one of the preceding claims, wherein a tolerance ring (31) is arranged around the overmolding (13) or the stator (11).Electronically commutated fluid pump according to any of the preceding claims, wherein said fluid pump (1) comprises at least one flow path.

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