Liquid pump with optimized cooling and heat dissipation

Abstract

Liquid pump, comprising a housing (1) in which a wound stator (2) and electronics (3) are arranged in a dry chamber (4), a permanent magnet rotor (5) arranged in a wet chamber (6), an axle (7) held on one side in a pump head (8) and on the other side in an axle receptacle (9) in a containment shell (10), wherein the containment shell (10) separates the dry chamber (4) from the wet chamber (6) and includes at least one bearing (11) which is incorporated in the permanent magnet rotor (5) and rotatably mounts it on the axle (7), the permanent magnet rotor (5) comprising a plastic insert (12) and a permanent magnet (13), characterized in that at least one axially parallel fluid channel (14) is formed between the plastic insert (12) and the permanent magnet (13) and that a permanent magnetic material forms at least one projection (19) on a lower side (18) of an impeller (15). is,which is arranged radially around a partial area of ​​the plastic insert (12) and encloses at least one injection point (22) which is formed on an outer surface (20) and / or an inner surface (21) of the at least one projection (19) and forms the permanent magnet rotor (5).

Description

[0001] The invention relates to a liquid pump according to the preamble of claim 1 and to a method for manufacturing a liquid pump according to claim 13.

[0002] Known liquid pumps have a multi-part housing with a dry chamber and a wet chamber. A rotor is located in the wet chamber and is surrounded by a fluid. A containment shell separates the wet chamber from the dry chamber and houses the rotor. The stator is located in the dry chamber. Most known liquid pumps also have an additional electronics compartment housing the control electronics. The fluid is directed into the wet chamber via an impeller and flows around the rotor. It is also known to incorporate axial fluid channels in the form of recesses in the area of ​​a radial bearing. A disadvantage of this is a reduced force distribution due to the consequently smaller bearing area. Furthermore, dirt particles and foreign matter from the fluid flow can be unintentionally transported directly into the bearing and accumulate there, potentially damaging the pump.It is also known to form fluid channels that arise during assembly. The disadvantage of this is that it creates additional assembly effort and reduces the area available for force-fit connections.

[0003] DE 10 2021 131 017 A1 discloses a liquid pump with a housing in which a wound stator and electronics are arranged in a dry chamber, a permanent magnet rotor arranged in a wet chamber, an axle which is held on one side in a pump head and on the other side in an axle receptacle in a containment shell, wherein the containment shell separates the dry chamber from the wet chamber and at least one bearing which is incorporated in the permanent magnet rotor and rotatably arranges it on the axle, wherein the permanent magnet rotor comprises a plastic insert and a permanent magnet and that at least one fluid channel is formed on the plastic insert.

[0004] DE 100 51 239 A1 discloses a liquid pump comprising a housing in which a wound stator and electronics are arranged in a dry compartment, a permanent magnet rotor arranged in a wet compartment, and an axle held on one side in a pump head and on the other side in an axle receptacle within a containment shell, the containment shell separating the dry compartment from the wet compartment. The permanent magnet rotor consists of a first hub section with an outer boundary surface and a hollow second hub section. The second hub section, with an inner boundary surface, surrounds the first hub section, and the boundary surfaces of both hub sections form flow channel contours, which together constitute at least one flow channel. The outer boundary surface of the first hub section is at least partially conical or wedge-shaped, and the inner boundary surface of the second hub section is equivalently conical or wedge-shaped.The first hub part is made of soft magnetic material and acts as a magnetic return to the second hub part, which consists of plastic-bonded permanent magnet material.

[0005] The object of the invention is to propose a liquid pump that overcomes the aforementioned disadvantages and ensures optimal cooling and heat dissipation. Furthermore, it aims to guarantee higher temperature resistance without affecting the dirt load capacity or bearing quality.

[0006] This problem is solved by the features according to claim 1 and by the features according to the method according to claim 13.

[0007] A liquid pump comprises a housing in which a wound stator and electronics are arranged in a dry compartment, a permanent magnet rotor located in a wet compartment, and a shaft held at one end in a pump head and at the other end in a shaft receptacle within a containment shell. The containment shell separates the dry compartment from the wet compartment. The liquid pump also has at least one bearing integrated into the permanent magnet rotor, for example, by press-fitting, injection molding, or by frictional and positive engagement. The bearing rotatably mounts the permanent magnet rotor on the shaft. The permanent magnet rotor includes a plastic insert and a permanent magnet. At least one fluid channel running parallel to the shaft is formed between the plastic insert and the permanent magnet.This creates a fluid channel that connects the fluid area of ​​an impeller to an inner wall of the containment cup, which is mounted on a printed circuit board. This increases fluid exchange and improves cooling performance on the circuit board.

[0008] The advantage is that the fluid channel is not located in the area of ​​the radial bearings. Consequently, the surface area for force-fit connections is increased, the quality of the rotor's concentricity is improved, a higher possible radial load is enabled by a larger running surface, and a higher resistance to dirt is ensured, since the fluid exchange does not occur via the bearings.

[0009] The plastic insert has an inner contour for the axle and at least one bearing. The inner area is precisely shaped to fit the axle and the at least one bearing during the injection molding process.

[0010] Permanent magnetic material encloses the at least one projection and the at least one injection point, forming the permanent magnet rotor. By enclosing the at least one projection and the at least one injection point, the permanent magnetic material is radially secured against slipping off the plastic insert.

[0011] An advantage is that at least one projection is formed on the underside of the impeller, which is arranged radially around a portion of the plastic insert. The projection is ring-shaped around the upper area of ​​the plastic insert.

[0012] At least one injection point is formed on the outer and / or inner surface of the at least one projection. This injection point provides volume within the injection mold and is essential for plastic injection. One or more injection points are arranged radially symmetrically on the outer and / or inner surface of the at least one projection, ensuring uniform filling of the plastic insert. A further advantage of the at least one injection point is the relatively quick and consistent application of the plastic during injection molding.

[0013] In a further development, the plastic insert and impeller are formed in one piece from the same material. Here, the plastic insert and the impeller are preferably made of a non-magnetic material, such as PPS (polyphenylene sulfide) or another thermoplastic material known to those skilled in the art.

[0014] In a further advantageous embodiment, the plastic insert has at least one axially parallel rib on its outer circumferential surface. This at least one rib can be variably adapted to the length of the plastic insert. The at least one rib ensures optimal plastic flow during the production of the plastic insert. The plastic flows to the designated locations in the injection mold and forms the plastic insert before the plastic hardens.

[0015] In another advantageous embodiment, the plastic insert is rib-free on its outer circumferential surface.

[0016] In a further advantageous embodiment, at least one material flattening is formed on the outer and / or inner surface of the at least one projection. This material flattening serves as an orientation aid for the plastic insert in the mold before the plastic insert is overmolded with permanent magnetic material.

[0017] It is advantageous that the at least one projection has at least one recess facing the underside of the impeller. This recess serves as axial securing of the permanent magnetic material against axial slippage off the plastic insert. Due to the adhesion of the permanent magnetic material to the recess, unintentional axial disassembly does not occur.

[0018] In an alternative embodiment, the plastic insert and a permanent magnet are designed as prefabricated components that are assembled together by force-fit, material-fit, or form-fit, thereby forming the permanent magnet rotor. The prefabricated components can be joined by pressing, gluing, or other assembly methods known to those skilled in the art.

[0019] It is advantageous that at least one fluid bore is formed in the impeller.

[0020] It is advantageous that the at least one fluid bore is positioned in an area between the inner surface of the at least one projection and the plastic insert, and / or that the at least one fluid bore forms a flow channel with the at least one axially parallel fluid channel. The flow channel is formed circumferentially between the plastic insert and the permanent magnet. This is advantageous because the at least one axially parallel fluid channel is not located in the area of ​​the radial bearing. This increases the area for force-fit connections, improves the concentricity of the rotor, allows for a higher possible radial load due to a larger running surface, and ensures a higher resistance to dirt, since the fluid exchange does not occur via the bearing.

[0021] In a further development, a cover plate with at least one through-opening is arranged on the impeller and corresponds to the at least one fluid bore in the impeller and the at least one axially parallel fluid channel. Dirt particles or foreign bodies are drained from the fluid flow through the through-opening in the cover plate and cannot enter the at least one fluid channel.

[0022] It is also advantageous to provide that a fluid flows around the permanent magnet rotor inside the containment shell. The fluid flow around the permanent magnet within the containment shell forms a primary cooling path. The fluid also serves as a lubricant for the at least one bearing. Venting at the at least one bearing is advantageously ensured by the at least one axially parallel fluid channel.

[0023] In a further embodiment, at least one axially parallel fluid channel in the plastic insert transports the fluid via a secondary flow path. This secondary flow path serves for heat dissipation and cooling of the electronics on the circuit board via the containment pot and the fluid. The base of the containment pot is in direct contact with the circuit board. Additionally, a thermally conductive film or thermal paste can be placed between the base of the containment pot and the circuit board to improve heat dissipation. It is important that there is no air gap between the base of the containment pot and the circuit board, or between the circuit board, the thermally conductive film or thermal paste, and the base of the containment pot.

[0024] The housing consists of a cantilevered section of the containment shell, the pump head, and a motor housing. The cantilevered section, the pump head, and the motor housing are bolted together. A seal is installed between each housing component. Alternatively, instead of bolting the housing components together, they can also be welded or joined using another material-, form-, or force-fit method known to those skilled in the art.

[0025] It may be intended, in particular, that the liquid pump will be used in water pumps, oil pumps, fuel pumps, SCR pumps in the automotive sector or in the household sector.

[0026] Furthermore, a method for manufacturing a liquid pump is provided, comprising the following process steps: a) A plastic insert with a paddle wheel is injection molded in one piece from the same material; b) In injection molding, at least one axially parallel rib is formed on the outer circumferential surface of the plastic insert, or the outer circumferential surface of the plastic insert is formed without ribs; c) In addition, during injection molding, at least one projection is formed on the underside of the impeller, which is arranged radially around a partial area of ​​the plastic insert, has at least one injection point and at least one material flattening on its outer surface and / or its inner surface, and has at least one recess in the direction of the underside of the impeller; d) In a further step, the permanent magnetic material encloses the at least one projection and the at least one injection point, thereby forming the permanent magnet rotor in injection molding; e) When attaching the permanent magnetic material to the plastic insert, at least one axially parallel fluid channel is formed between the plastic insert and the permanent magnet.

[0027] The formation of at least one rib on the outer circumferential surface of the plastic insert balances the rotor before the permanent magnet material is applied to the insert. This ensures optimal rotor concentricity. Furthermore, the rib creates a better interlocking connection between the plastic insert and the permanent magnet material during injection molding.

[0028] When the permanent magnetic material is applied to the plastic insert, at least one axially parallel fluid channel is formed between the plastic insert and the permanent magnet. Additional axially parallel fluid channels are also possible. Unused fluid channels can be filled with permanent magnetic material. The at least one axially parallel fluid channel transitions into a circumferential fluid channel in the lower region of the plastic insert. If there are multiple axially parallel fluid channels, they are arranged radially symmetrically, i.e., two fluid channels opposite each other, three fluid channels offset by 120 degrees from each other, etc. Reference symbol list 1 case 2 Stator 3 Electronics 4 Drying room 5 permanent magnet rotor 6 Wet room 7-axis 8 Pump head 9 axle mounting 10 Split pot 11 warehouses 12 plastic inserts 13 Permanent magnet 14 Fluid channel 15 impeller 16 External perimeter area 17th rib 18 Underside 19 Cantilever 20 outdoor area 21 interior surface 22 Injection point 23 Material flattening 24 Exclusion 25 Fluid bore 26 Cover plate 27 Passage opening 28 Fluid 29 Liquid pump 30 Cantilever split pot 31 Motor housing 32 Recording contour

[0029] The invention is explained in more detail below with reference to exemplary embodiments and the accompanying drawings. These show: Fig. 1. An overview of a liquid pump according to one embodiment, Fig. 2 a sectional view of a permanent magnet rotor according to Fig. 1, Fig. 3 an isometric view of a plastic insert according to one embodiment, Fig. 4 a top view of the plastic insert according to Fig. 3, Fig. 5 a top view of the permanent magnet rotor according to one embodiment, Fig. 6 a top view of a cover plate; Fig. 7 a sectional view of a liquid pump according to one embodiment.

[0030] Fig. Figure 1 shows an overview of a liquid pump (29) according to one embodiment. The liquid pump (29) comprises a housing (1) in which a wound stator (2) and electronics (3) are arranged in a dry chamber (4). The liquid pump (29) further comprises a permanent magnet rotor (5) arranged in a wet chamber (6) and a shaft (7) which is held on one side in a pump head (8) and on the other side in a shaft receptacle (9) in a containment shell (10). The containment shell (10) separates the dry chamber (4) from the wet chamber (6). Furthermore, at least one bearing (11) is provided, which is integrated into the permanent magnet rotor (5) and rotatably mounts it on the shaft (7). The permanent magnet rotor (5) comprises a plastic insert (12) and a permanent magnet (13). At least one axially parallel fluid channel (14) is also formed between the plastic insert (12) and the permanent magnet (13).The individual housing parts can be screwed, welded, or joined together by any other material-, form-, or force-fit method known to those skilled in the art. In particular, a connection can be achieved by means of a projection (30) of the containment shell (10), which, together with the pump head (8) and a motor housing (31), forms the housing.

[0031] Fig. Figure 2 shows a cross-sectional view of a permanent magnet rotor according to Fig. 1. The plastic insert (12) is formed in one piece with a rotor (15) made of the same material and forms the permanent magnet rotor (5) by overmolding with permanent magnet material. In particular, the plastic insert (12) and one or the permanent magnet (13) are designed as finished parts that are assembled into one another by force-fit, material-fit, or form-fit, thereby forming the permanent magnet rotor (5). The plastic insert (12) is at least as long as the permanent magnet (13). Preferably, the plastic insert (12) is shorter so that it does not rest on the axle receptacle of the containment pot (10), i.e., the plastic insert does not touch the bottom of the containment pot. However, it would also be conceivable for the plastic insert (12) to be longer than the permanent magnet (13). The length of the plastic insert (12) is thus variably adapted to the length of the permanent magnet (13).For a circumferential flushing channel, it is advantageous for the plastic insert (12) to be shorter in length than the permanent magnet (13). The fluid channel (14) is formed by at least one fluid bore (25) in the impeller (15). In its inner area, the plastic insert (12) has a receiving contour (32) for the shaft (7) and the at least one bearing (11). When the permanent magnet material is attached to the plastic insert (12), at least one axially parallel fluid channel (14) is formed between the plastic insert (12) and the permanent magnet (13).

[0032] Fig. Figure 3 shows an isometric view of the plastic insert (12) according to an embodiment, in which it is disclosed that the plastic insert (12) has at least one axially parallel rib (17) on its outer circumferential surface (16) or is rib-free. The at least one rib can be formed on the entire outer circumferential surface (16) or only partially on the outer circumferential surface (16). At least one projection (19) is formed on a lower surface (18) of the impeller (15), which extends radially around a partial area of ​​the plastic insert (12). At least one injection point and at least one material flattening (23) are formed on the outer surface (20) and / or the inner surface (21) of the at least one projection (19). In addition, the at least one projection (19) has at least one recess (24) in the direction of the lower surface (18) of the impeller (15).The impeller (15) has at least one fluid bore (25) and / or the at least one fluid bore (25) is positioned in an area between the inner surface (21) of the at least one projection (19) and the plastic insert (12) and / or the at least one fluid bore (25) forms a flow channel with the at least one axially parallel fluid channel (14) (not shown here).

[0033] Fig. Figure 4 shows a top view of the plastic insert (12) according to Fig. 3.

[0034] Fig. Figure 5 shows a top view of the permanent magnet rotor (5) according to one embodiment. The permanent magnet rotor (5) comprises the plastic insert (12) and a permanent magnet (13). The plastic insert (12) has at least one axially parallel rib (17) on its outer circumferential surface (16). Alternatively, the outer circumferential surface (16) can also be designed without ribs (17). At least one projection (19) is formed on the underside (18) of the impeller (15), which is arranged radially around a portion of the plastic insert (12). During the injection molding process, permanent magnetic material encloses the at least one projection (19) and the at least one injection point (22) (not shown here) and forms the permanent magnet rotor (5).When the permanent magnetic material is applied to the plastic insert (12), at least one axially parallel fluid channel (14) is formed, which corresponds to the at least one fluid bore (25) in the impeller (15).

[0035] Fig. Figure 6 shows a top view of a cover plate (26) according to an embodiment, which is arranged on the impeller (15). The cover plate (26) comprises at least one through-opening (27) and forms at least one axially parallel fluid channel (14) with the at least one fluid bore (25) in the impeller (15). Dirt particles or foreign bodies are discharged from the fluid flow through the through-opening (27) in the cover plate (26) and cannot enter the at least one fluid channel (14).

[0036] Fig.Figure 7 shows a cross-sectional view of a liquid pump according to one embodiment. A fluid (28) can be seen flowing around the permanent magnet rotor (5) within the containment shell (10). This is a primary cooling path, supplied by the at least one fluid bore (25). The fluid (28) is also conveyed through a secondary flow path via the at least one axially parallel fluid channel (14) in the plastic insert (12). The secondary flow path serves for heat dissipation and cooling of the electronics on the circuit board via the containment shell (10) and the fluid (28).

Claims

[1] Liquid pump, with a housing (1) in which a wound stator (2) and electronics (3) are arranged in a dry space (4), a permanent magnet rotor (5) which is arranged in a wet space (6), an axle (7) which is held on the one hand in a pump head (8) and on the other hand in an axle holder (9) in a containment shell (10), wherein the containment shell (10) separates the dry space (4) from the wet space (6) and at least one bearing (11) which is introduced into the permanent magnet rotor (5) and arranges it rotatably on the axle (7), the permanent magnet rotor (5) comprises a plastic insert (12) and a permanent magnet (13), characterized bythat at least one fluid channel (14) running parallel to the axis is formed between the plastic insert part (12) and the permanent magnet (13), and that a permanent magnetic material surrounds at least one projection (19) formed on an underside (18) of an impeller (15) which is arranged radially around a partial region of the plastic insert part (12), and at least one injection point (22) formed on an outer surface (20) and / or an inner surface (21) of the at least one projection (19), and forms the permanent magnet rotor (5). [2] Liquid pump according to one of the preceding claims, characterized by that the plastic insert (12) is formed in one piece with the impeller (15) from the same material. [3] Liquid pump according to one of the preceding claims, characterized by that the plastic insert (12) has at least one axially parallel rib (17) on an outer peripheral surface (16). [4] Liquid pump according to claim 1 or 2, characterized by that the plastic insert (12) is designed to be rib-free on an outer peripheral surface (16). [5] Liquid pump according to claim 1, characterized by that at least one material flattening (23) is formed on the outer surface (20) and / or the inner surface (21) of the at least one projection (19). [6] Liquid pump according to claim 1, characterized by that the at least one projection (19) has at least one recess (24) in the direction of the underside (18) of the impeller (15). [7] Liquid pump according to one of claims 2 to 6, characterized by that at least one fluid bore (25) is formed in the impeller (15). [8] Liquid pump according to claim 7, characterized bythat the at least one fluid bore (25) is positioned in a region between the inner surface (21) of the at least one projection (19) and the plastic insert (12) and / or that the at least one fluid bore (25) forms a flow channel with the at least one fluid channel (14) running parallel to the axis. [9] Liquid pump according to claim 8, characterized by that a cover plate (26) with at least one through-opening (27) is arranged on the impeller (15) and corresponds to the at least one fluid bore (25) in the impeller (15) and the at least one fluid channel (14) running parallel to the axis. [10] Liquid pump according to one of the preceding claims, characterized by that a fluid (28) flows around the permanent magnet rotor (5) within the containment shell (10). [11] Fluid pump after clutch (K3), characterized bythat the at least one axially parallel fluid channel (14) between the plastic insert (12) and the permanent magnet (13) transports the fluid (28) via a secondary flow path. [12] Liquid pump according to one of the preceding claims, characterized by that the liquid pump is used in water pumps, oil pumps, fuel pumps, SCR pumps in the automotive sector or in the household sector. [13] A method for producing a liquid pump according to any one of the preceding claims, characterized by , that a) a plastic insert (12) is injection-molded in one piece with an impeller (15) made of the same material; b) during injection molding, at least one axially parallel rib (17) is formed on the outer peripheral surface (16) of the plastic insert (12) or the outer peripheral surface (16) of the plastic insert (12) is formed without ribs; c) during injection molding, at least one projection (19) is formed on an underside (18) of the impeller (15), which projection is arranged radially around a partial area of ​​the plastic insert (12), at least one injection point (22) and at least one material flattening (23) is formed on its outer surface (20) and / or its inner surface (21) and has at least one recess (24) in the direction of the underside (18) of the impeller (15); d) that in a further step, the permanent magnetic material encloses the at least one projection (19) and the at least one injection point (22) and thereby forms the permanent magnet rotor (5) during injection molding; and e) that when the permanent magnetic material is applied to the plastic insert (12), at least one fluid channel (14) running parallel to the axis is formed between the plastic insert (12) and the permanent magnet (13).

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