Fluid pump with improved drive cooling

Abstract

The invention relates to a fluid pump with an electric drive unit (2) and a fluid pump module (3), wherein the electric drive unit (2) is coupled to the fluid pump module (3) for driving the fluid pump module (3), wherein an interior space (8) of the drive unit (2) is fluidically connected to a pump chamber (4) of the fluid pump module (3), so that during operation of the fluid pump (1), the fluid (16) to be pumped acts as a cooling medium (10) for the drive unit (2) and flows through the interior space (8) of the drive unit (2) along at least one flow path (SP), wherein an end (13) of a rotor (6) of an electric motor (7) arranged in the electric drive unit (2), facing away from the pump module (3) in an axial direction (A), is provided with blades (14) which form an end-side blading (15) of the rotor (6).

Description

[0001] The invention relates to a fluid pump according to the preamble of claim 1.

[0002] A fluid pump of this type is known from DE 10 2018 104 770 A1.

[0003] Such a fluid pump has proven its worth, however, there remains a need to improve heat dissipation from electronic components of a pump control, with the aim of minimizing or eliminating any loss of efficiency.

[0004] These problems are solved with a fluid pump having the features of claim 1; advantageous embodiments are specified in the dependent claims.

[0005] A fluid pump according to the invention has an electric drive unit and at least one fluid pump module, wherein the electric drive unit is coupled to the fluid pump module for driving the fluid pump module, wherein an interior space of the drive unit is fluidically connected to a pump chamber of the fluid pump module, so that during operation of the fluid pump, the fluid to be pumped acts as a cooling medium for the drive unit and flows through the interior space of the drive unit along at least one flow path SP. wherein an end of a rotor of an electric motor arranged in the electric drive unit, viewed in an axial direction A away from the pump module, is provided with blades which form an end blading of the rotor.

[0006] With this type of fluid pump, a relatively strong annular flow of fluid located inside the drive unit is generated in the area between the rotor's far end and an electronics module positioned axially behind it. This results in direct fluid circulation around components mounted on the electronics module, thus improving heat dissipation generated within the module's components. The rotor's blades create a free-flowing annular flow, actively circulating the fluid around the electronics module components. While the blades increase the local flow velocity, they are not responsible for transporting the fluid inside the drive unit from a fluid inlet to a fluid outlet, as described below.Such a general transport of the fluid through the interior of the drive unit is ensured by a pressure difference between an inlet and an outlet from the interior, i.e. by an external pressure gradient.

[0007] It can be advantageous to arrange an electronics module axially opposite the end of the rotor in the interior of the drive unit, with the components of the electronics module in particular pointing towards the end of the rotor.

[0008] With such an arrangement, it is possible to direct the ring flow of the fluid generated by the rotor together with the blading inside the drive unit as directly as possible past the heat-generating or heat-emitting components of the electronic module, thus ensuring a high heat transfer.

[0009] Furthermore, it is advantageous that overflow openings are provided for the fluidic connection of the interior of the drive unit with the pump chamber of the fluid pump module, which open at one end into a pressure area of ​​the pump chamber of the fluid pump module and at the other end into the interior of the drive unit.

[0010] This measure makes it convenient to use a pressure gradient within the pump chamber to ensure a flow through the interior of the drive unit without additional pumping or conveying equipment for the fluid to be pumped within the drive unit.

[0011] For the design of the overflow openings, it may be advantageous for the overflow openings to be aligned parallel to the axial direction (A) or obliquely to the axial direction (A), wherein in the case of an oblique alignment at least one pump-room-side end of the overflow openings is arranged to point towards a fluid flow arriving locally in the inlet area.

[0012] In the case of a parallel alignment to the axial direction A, it is advantageous that the production of such overflow openings is particularly simple, for example by drilling parallel to the axial direction A. In the case of an oblique arrangement of the overflow openings, a slightly higher manufacturing effort is required for the overflow openings, but the flow of fluid into the interior of the drive unit can be facilitated, since a smaller angular deflection of the fluid from the pump chamber is necessary to pass through the overflow openings.

[0013] To return applied fluid from the interior of the drive unit, it may be advantageous to have return flow openings for the fluidic connection between the interior of the drive unit and the pump chamber of the fluid pump module, which open on the pump chamber side into an area that has a lower pressure compared to the overpressure area of ​​the pump chamber.

[0014] This measure ensures a reliable flow through the drive unit.

[0015] A particularly simple provision of return flow openings can be achieved by forming the return flow openings through a combined bearing through which the flow passes, for example, as a rolling bearing.

[0016] One possible arrangement variant of the blades at the end of the rotor can be designed such that the blades of the end blading of the rotor are arranged radially to a rotation axis RA of the rotor, which extends along the axial direction A.

[0017] An alternative arrangement variant of the blades at the end of the rotor consists in the blades 14 of the end blading of the rotor being arranged at an angle to the radial direction RA.

[0018] To form a return flow path and thus to guide the return fluid to the return flow openings in a targeted manner, it is advantageous for the rotor 6 of the electric motor to have return flow channels which open at one end at the end of the rotor facing away from the pump module into an area between the end of the rotor facing away from the pump module and the electronic module and communicate fluidically with the return flow openings at the other end.

[0019] This makes it possible to create a circulating flow when viewed in a longitudinal section through a fluid pump, whereby fresh, cool fluid from the pump chamber can flow radially further out from the inlet point into the interior of the drive unit to an area in front of the electronic module, whereas the return flow is guided radially further inwards through radially inwards return openings in the rotor, which are approximately aligned with the flow openings, for example formed by the flowable compact bearings.

[0020] As a radially outward-positioned inflow path, it may be permissible for a gap between the rotor and a stator surrounding the rotor to form an inlet channel. However, a significant amount of heat generated in the annular gap between the rotor and the stator can also be absorbed by the fluid.

[0021] To form radially very far outward inflow paths, it may be advantageous for an outer circumferential surface of the stator to form at least one further inflow channel together with an inner surface of a drive housing, wherein the at least one further inflow channel runs parallel to the axial direction A or obliquely to the axial direction A or helically along the outer circumferential surface of the stator.

[0022] To ensure the most unimpeded possible supply of cool fluid from the pump chamber directly to the electronic module, it may also be advantageous for the fluid pump to include a second flow channel, which is separate from the interior of the drive unit and opens at one end into a high-pressure area, preferably behind a pump impeller of the pump module, within the interior of the pump module, and at the other end into an ambient area around a component subjected to high temperatures, for example an ECU, so that it can be directly exposed to the flow.

[0023] Fluid pump according to one of the preceding claims, characterized in that the blades of the blading are formed by webs, in particular by webs projecting in the axial direction A, or by a ramp pattern seen in a circumferential direction U.

[0024] To improve the flow to individual components of the electronic module and thus to improve the heat dissipation of these components, it may be advantageous to adapt the assembly of the electronic module with its components to a ring flow created by the rotor's blading.

[0025] To optimize heat dissipation, it is advantageous that the entire interior of the drive unit is filled with fluid, so that both the stator and the rotor of the electric motor as well as the electronic module are completely wetted up to their contact surfaces with adjacent components.

[0026] The invention will now be explained by way of example with reference to the drawings. The drawings show: Fig. 1: a longitudinal section through a fluid pump according to the invention in the form of a centrifugal pump; Fig. 2 A: a perspective view of an end of a rotor of a fluid pump according to the invention facing away from the pump module, having an end-side radial blading in a first embodiment; Fig. 2 B: a perspective view of an end of a rotor of a fluid pump according to the invention facing away from the pump module, having an end-side radial blading in a second embodiment; Fig. 3: A schematic, perspective view of a rotor positioned opposite an electronics module and a schematic representation of a ring flow generated by the rotor's blades (illustrated by flow lines)

[0027] A fluid pump 1 according to the invention ( Fig. 1) comprises an electric drive unit 2 and a fluid pump module 3, in which a pump impeller 5 is arranged in a pump chamber 4. The pump impeller 5 is rotationally fixed to a rotor 6 of an electric motor 7. The electric motor 7 is arranged in an interior space 8 of a drive housing 9 of the drive unit 2.

[0028] The rotor 6, together with a surrounding stator 10, forms the electric motor 7, which has electrical connection devices 11A connected to corresponding electrical counter-connection devices 11B. The corresponding electrical counter-connection devices 11B are located on an electronic module 12, which, viewed in the axial direction A, is arranged directly adjacent to an end 13 of the rotor 6 facing away from the impeller 4, i.e., without any intermediate partitions, within the interior 8 of the drive unit 2. The electronic module 12 essentially comprises a carrier board 12A, the planar extent of which is essentially perpendicular to the axial direction A. On a side 12B of the carrier board 12A facing the rotor 6, components 12C, for example, active and / or passive electronic components, are arranged.The assembly components protrude from side 12 B towards the opposite end 13 of the rotor 6.

[0029] The rotor 6 has, at its end 13 facing away from the pump wheel 4, blades 14, in particular a plurality of blades 14, which project in a circumferential direction U from an end face at the end 13 facing away from the electronic module 12 in the axial direction A from the end 13 facing away from the pump wheel 4, which project in a circumferential direction U from an end face at the end 13 facing away from the pump wheel 4.

[0030] The majority of the blades 14 thus form a frontal blading 15 of the rotor 6. The blades 14 are rigidly connected to the rotor 6 and therefore rotate with the rotor 6 during operation of the fluid pump 1.

[0031] At least a portion, preferably the entire interior 8 of the drive unit 2, is filled with a subset of a fluid 16 to be pumped by the fluid pump 1 and acts as a cooling medium 17 within the drive unit 2 for components located in the interior 8 of the drive unit 2. The drive unit 2, or rather its drive housing 9, is closed axially on one side by a cover 20, wherein, in the present embodiment, the cover 20 mechanically supports the electronic module 12 on its side facing the interior 8. The cover 20 also has a mechanical receptacle 21 for a connector module 22. The connector module 22 encloses connection pins 23, which are electrically connected at one end to the carrier board 12A of the electronic module 12 and are designed and configured at the other end for contact with a mating connector module (not shown).

[0032] The cooling system for improved cooling of fluid pump 1 is explained in more detail below. Here, we show in the Fig. 1. The first arrows 24 with a single tip indicate a flow path SP for the fluid 16 to illustrate the general flow through the drive unit 2. Furthermore, in the Fig. One thinner second arrow 25 with a double tip is shown, which is intended to represent heat removal or heat flow.

[0033] Furthermore, it should be explained that in a region between the impeller 4 and the drive housing 9 or its end wall 9A, a spatial sub-region of the pump chamber 5 exists in which, during operation of the fluid pumps 1, a region with a relatively low fluid pressure is located radially further inwards in a radial direction R, and a region with a relatively higher fluid pressure (overpressure region 60) is located radially further outwards. In other words, this means that in the space between the impeller 5 and the end wall 9, the pressure of the fluid 16 present there increases radially outwards.

[0034] In a radially outer region, overflow openings 30 are located, which penetrate the end wall 9A and thus fluidically connect the pump chamber 4 with the interior 8 of the drive unit 2. Radially further inward relative to the overflow openings 30, a bearing, in particular a combination bearing 31, is provided, which guides the rotor 6 of the electric motor 7 radially and axially. The bearing, in particular the combination bearing 31, is designed to be fluid-permeable in the axial direction A, so that, for example, return flow openings 32 are formed between the rolling elements of the combination bearing. Through these openings, fluid 16 from the interior 8 of the drive unit 2 can flow back into the pump chamber 4, in particular into the area between the impeller 4 and the end wall 9A, in a region with lower fluid pressure, i.e., radially further inward relative to the overflow openings 30.In the usual manner, a gap 33 exists between the rotor 6 and the stator 10 of the electric motor 7. Fluid entering the interior 8 of the drive unit 2 via the overflow openings 30 can flow axially through this gap towards the cover 20 into the intermediate area between the far end 13 of the rotor 6 and the electronic module 12. To return the fluid from this area, the rotor 6 has return flow channels 35 extending in the axial direction A. These channels rotate circumferentially with the rotor 6 when the fluid pump 1 is operating. Viewed in the axial direction A, the return flow channels 35 open approximately into the return flow openings 32 of the combination bearing 31, allowing the fluid 16 to easily flow from the return flow channels 35 of the rotor 6 into the return flow openings 32 and thus easily back into the pump chamber 4.

[0035] Optionally, additional channels extending in the axial direction A can be provided between the outer surface of the stator 10 and the drive housing 9, allowing fluid to flow radially from the overflow openings 30 into the area between the rotor 6 and the electronic module 12. As a result, a partial flow path SP is formed from the overflow openings 30 via the gap 23 or via large sections of radially outer channels formed between the stator 10 and the housing 9, in which the fluid 16 flows into the area between the rotor 6 and the electronic module 12. A reverse flow occurs from the area between the rotor 6 and the electronic module 12 back into the pump chamber 4 via the reverse flow channels 35 and the reverse flow openings 32.

[0036] Thus, in longitudinal section according to Fig. 1 a circulating flow is generated which flows radially outside from the pump chamber 4 to the space between the rotor 7 and the electronic module 12 and radially inside from the space between the rotor 6 and the electronic module 12 back into the pump chamber 4.

[0037] In the space between the rotor 6 and the electronic module, the prescribed circulating flow during operation of the fluid pump 1 is superimposed with an annular flow by the rotational movement of the rotor 6 in the circumferential direction U. This annular flow is forced upon the fluid 16 located in the space between the rotor 6 and the electronic module 12. Such an annular flow is, for example, Fig. 3 indicated by thin flow lines 40. This is shown in the view according to Fig. The electronic module 12 shown below carries the component parts 12C on side 12B, which faces the rotor 6. The rotor 6 has blades 14 on its end face, i.e., on the end face facing the electronic module 12 (not shown in Figure 3). Fig. 3, compare Fig. 2 A, Fig. 2 B and Fig. 1) which superimpose the ring flow / flow lines 40 of the circulation flow and / or imprint locally in the area between the electronic module 12 and the far end 13 of the rotor 6.

[0038] The ring flow / flow lines 40 thus locally generates an accelerated fluid flow, which particularly intensively washes around the component parts 12C which protrude from the front face 12B of the carrier board 12A towards the rotor 6 and thus ensures good heat transfer between the component parts 12C and the fluid 16, which acts as a cooling medium 17 in this area.

[0039] In a particularly preferred embodiment, the component parts 12C are arranged on the carrier board 12A in a manner adapted to the annular flow 40 or to the flow lines 41 of the annular flow 40, such that, for example, flow channels preferably form between the component parts 12C, thus ensuring a particularly intensive flow around the component parts 12C. If the component parts 12C are equipped, for example, with passive heat sinks (not shown), it is recommended to align the fin structures of the heat sinks in a flow-optimized manner with respect to the flow lines 40 or the annular flow 40.

[0040] The Fig. 2 A and Fig. Figure 2B shows two different embodiments of rotors 6 of the electric motor 7, both of which have the blading 15 with blades 14 in the form of radial webs. The rotor 6 in the embodiment according to Fig. 2 A is not cylindrical on its outer surface in the circumferential direction U, but has local depressions 50 between the lamination stacks. Such depressions 50 can, for example, cause locally enlarged gap cross-sections of the gap 33, but are rather disadvantageous, since the flow resistance of the rotor 6 in the circumferential direction U embedded in fluid 16 is higher compared to an embodiment according to Fig. 2 B is slightly increased. The embodiment according to Fig. Figure 2B shows a rotor 6 with a cylindrical outer surface extending circumferentially without local depressions, which is wetted by fluid located in the gap 33. Such an embodiment of the rotor is more aerodynamically efficient in the circumferential direction U than the embodiment according to [reference missing]. Fig. 2 A. The blading 15 of the far end 13 of the rotors 6 according to the embodiments according to Fig. 2 A, Fig.2 B, can alternatively or additionally also be formed by radial webs that extend at an angle to the radial direction R.

[0041] Furthermore, in a modified embodiment, the blading 15 can be formed by a frontal ramp pattern extending in the circumferential direction U (not shown), for example with wedge-shaped ramps (not shown) that are arranged on the frontal side of the far end 13. Reference symbol list 1 fluid pump 2 electric drive unit 3 Fluid pump module 4 Pump room 5 Pump wheel 6 Rotor 7 Electric motor 8 Interior of the drive unit 9 Drive housings 9A Front wall 10 Stator 11A electrical connection devices 11B corresponding electrical counter-connection devices 12 Electronic module 12A carrier board 12B Side of the carrier board facing rotor 6 12 A 12C assembly components 13 opposite end 14 shovels 15. Shoveling 16 fluid to be pumped 17 Cooling medium 20 sealing caps 21 mechanical recording 22 Connection module 23 connection pins 24 first arrows with a single point 25 second double-pointed arrows 30 overflow openings 31 combination storage units 32 backflow openings 33 gap 35 return flow channels 40 Ring flow 41 flow lines 50 local depressions SP flow path A Axial direction RA axis of rotation R Radial direction U circumferential direction UB overpressure area QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2018 104 770 A1

[0002]

Claims

Fluid pump with an electric drive unit (2) and a fluid pump module (3), wherein the electric drive unit (2) is coupled to the fluid pump module (3) for driving the fluid pump module (3), wherein an interior space (8) of the drive unit (2) is fluidically connected to a pump chamber (4) of the fluid pump module (3), so that during operation of the fluid pump (1), the fluid (16) to be pumped acts as a cooling medium (10) for the drive unit (2) and flows through the interior space (8) of the drive unit (2) along at least one flow path (SP), characterized in that an end (13) of a rotor (6) of an electric motor (7) arranged in the electric drive unit (2), facing away from the pump module (3) in an axial direction (A), is provided with blades (14) which form an end-side blading (15) of the rotor (6). Fluid pump according to claim 1, characterized in that an electronic module (12) is arranged axially opposite the end (13) of the rotor (6) in the interior (8) of the drive unit (2), wherein in particular assembly components (12C) of the electronic module (12) point towards the end (13) of the rotor (6). Fluid pump according to claim 1 or 2, characterized in that overflow openings (30) are provided for the fluidic connection of the interior (8) of the drive unit (2) with the pump chamber (4) of the fluid pump module (3), which open at one end into an overpressure area (UB) of the pump chamber (4) of the fluid pump module (2) and at the other end into the interior (8) of the drive unit (2). Fluid pump according to claim 3, characterized in that the overflow openings (30) are aligned parallel to the axial direction (A) or obliquely to the axial direction (A), wherein in the case of an oblique alignment at least one pump chamber-side end of the overflow openings (30) is arranged pointing towards a fluid flow arriving locally in the inlet area. Fluid pump according to one of claims 1 to 4, characterized in that return flow openings (32) are provided for the fluidic connection of the interior (8) of the drive unit (2) with the pump chamber (4) of the fluid pump module (2), which open on the pump chamber side into an area which has a lower pressure compared to the overpressure area (UB) of the pump chamber (4). Fluid pump according to claim 5, characterized in that the return flow openings (32) are formed by a flow-through combination bearing (31), which is designed as a rolling bearing. Fluid pump according to one of the preceding claims, characterized in that the blades (14) of the end blading (15) of the rotor (6) are arranged radially to an axis of rotation (RA) of the rotor (6), which extends along the axial direction (A). Fluid pump according to one of the preceding claims, characterized in that the blades (14) of the end blading (15) of the rotor (6) are arranged at an angle to a radial direction (R). Fluid pump according to one of the preceding claims, characterized in that the rotor (6) of the electric motor (7) has return flow channels (35) which open at one end at the end (13) of the rotor (6) facing away from the pump module (2) into a region between the end (13) of the rotor (6) facing away from the pump module (2) and the electronic module (12) and communicate fluidically with the return flow openings (32) at the other end. Fluid pump according to one of the preceding claims, characterized in that a gap (33) between the rotor (6) and a stator (10) surrounding the rotor (6) forms a first inlet channel of the flow path (SP). Fluid pump according to one of the preceding claims, characterized in that an outer circumferential surface of the stator (10) together with an inner surface of a drive housing (9) forms at least one further inlet channel of the flow path (SP), wherein the at least one further inlet channel runs parallel to the axial direction (A) or oblique to the axial direction (A) or helically along the outer circumferential surface of the stator (10). Fluid pump according to one of the preceding claims, characterized in that the fluid pump (1) comprises a second flow channel which is separated from the interior (8) of the drive unit (2) and opens at one end into an overpressure area (UB) of the pump chamber (4), preferably behind a pump impeller (5) of the pump module (2), and at the other end into an ambient area around a heat-stressed component, for example an electronic module (12), so that the electronic module (12) and / or component parts (12C) of the electronic module (12) can be directly exposed to the flow. Fluid pump according to one of the preceding claims, characterized in that the blades (14) of the blading (15) are formed by webs or by a ramp pattern extending along a circumferential direction (U). Fluid pump according to one of the preceding claims, characterized in that the assembly of the electronic module (12) with assembly components (12C) of the electronic module (12) is adapted to a ring flow (40) superimposed or pronounced by the blading (15) of the rotor (6). Fluid pump according to one of the preceding claims, characterized in that the entire interior (8) of the drive unit (2) is filled with fluid (16), so that both the stator (6) and the rotor (10) of the electric motor (7) as well as the electronic module (12) are completely wetted with fluid except for their contact surfaces on adjacent components.

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