Fluid pump and coolant delivery device for an internal combustion engine with such a

Abstract

Fluid pump (1) with an inner housing (4) and an outer housing (3), wherein the inner housing (4) defines an interior space (17) in which an electric motor with a stator (31) and a rotor (29) is arranged, the rotor (29) is coupled to an impeller (12) via a drive shaft (18), the outer casing (3) surrounds the impeller (12) and the inner casing (4) and the outer casing (3) form a flow channel (5) adjacent to the inner casing (4), in particular an annular flow gap connecting an inlet and an outlet end (6, 7), which are formed in particular at axially opposite ends of the outer housing (3), wherein a connection (40; 42; 43; 44) exists between the flow channel (5) and the interior space (17), so that a fluid conveyed through the flow gap (5) completely fills the interior space (17), surrounds the stator (31) and rotor (29), and the fluid improves heat transfer between the interior space (17) and the inner housing (4).

Description

The invention relates to a fluid pump, in particular an axial fluid pump, having an inner housing and an outer housing, wherein the inner housing defines an interior space in which an electric motor having a stator and a rotor are arranged, the rotor is coupled to an impeller (an impeller) via a drive shaft, and the outer housing surrounds the impeller. The inner housing and the outer housing form a flow channel adjoining the inner housing, in particular an annular flow gap between the outer housing and the inner housing, which flow gap connects a suction opening and a discharge opening, which are formed in particular at axially opposite ends of the outer housing.In the automotive sector, coolant pumps are used in the cooling circuit, the drive of which is coupled directly via belts or chain drives to the drive shaft of the internal combustion engine. However, such main mechanical coolant pumps rigidly coupled to the drive are only suitable to a limited extent for optimized thermal management in modern engines. Therefore, in addition or alternatively, independently driven and / or controllable coolant pumps are also provided.These are generally centrifugal pumps (for example of radial or semi-axial construction). As drive, permanently excited direct current motors are provided, for example, which have a high power density and are easily controllable with a compact construction. However, the cooling of such high-performance electric motors is not entirely unproblematic, especially in the field of internal combustion engines. On the one hand, they are arranged in a relatively warm environment and, on the other hand, due to their high power density during operation, they also develop dedicated waste heat which has to be removed reliably.For centrifugal pumps, an approach is known from EP 0 778 649 A1, in which a cooling body is provided, which adjoins the stator windings-the majority of the waste heat arises there-and which dissipates the operating heat arising in the stator windings or in the stator stack to the outside via the pump housing or via housing components of the spiral housing coming into contact with the cooling medium.Another approach according to DE 10 2011 009 192 B3 consists in providing a wet running region surrounding the drive shaft, its bearing and the rotor, which wet running region is sealed off from the current-carrying stator region via a can or a can. The wet running region is in communication with the scroll casing of the radial pump. The bearings of the drive shaft are lubricated with the coolant. Limited heat dissipation also takes place from the dry running stator region via the outer surfaces of the can into the wet running region.A similar approach is also followed by WO 2007 / 054171 A1, in which an electric fluid pump of semi-axial construction is provided, in which a can is likewise provided, which seals the outer stator region (dry running) and the inner rotor region (wet running) with respect to one another. The pumped fluid flows axially through the rotor region. The dry-running stator region adjoins with its outer circumferential surfaces the one coolant-carrying annular gap which surrounds an inner housing and is bounded on the outside by the outer housing of the pump, through which the coolant which is conveyed flows. However, the heat transfer to the flowing coolant from the stator region filled with air is limited.WO 2012 / 024778 A1 describes a fluid pump having a flow channel between an inner housing and an outer housing, which is defined by ribs between the inner housing and the outer housing. A rotor and a stator are arranged in the inner housing, wherein the stator is sealed with respect to a fluid.It is an object of the present invention to provide a fluid pump in which the disadvantages mentioned are at least partially overcome. This object is achieved by the fluid pump according to the invention as claimed in claim 1, the coolant delivery device as claimed in claim 9 and the internal combustion engine as claimed in claim 10.Further embodiments of the invention are evident from the dependent claims and the following description of exemplary embodiments of the present invention.A fluid pump according to the invention comprises an inner housing and an outer housing. The inner housing defines an interior space in which an electric motor having a stator and a rotor is arranged. The rotor is coupled to an impeller (impeller) via a drive shaft, the outer housing the impeller, wherein a flow duct, in particular an annular flow gap, adjoining the inner housing runs between the inner housing and the outer housing. This connects a suction and a discharge opening to one another, which are formed in particular at axially opposite ends of the outer housing. In such a pump, the impeller conveys the fluid (in particular a coolant) radially, axially or semi-axially through the flow channel or channels around the inner housing or along the latter.The invention is distinguished in that a connection exists between the flow channel, in particular an annular flow gap, and the interior space, so that the fluid conveyed through the flow channel floats this interior space, surrounds the stator and rotor, and the fluid thus forms a heat transfer medium between the stator and rotor on the one hand and the inner housing on the other hand.A plurality of effects are thus achieved. The rotor and the drive shaft are completely surrounded by the fluid which fills the interior space, which can thus serve as lubricant for the bearings of the drive shaft and absorbs and removes operating heat from the bearings or from the rotor. In addition, however, the stator surrounding the rotor is also surrounded by its current-carrying windings by the fluid which also passes through the so-called "air gap" between the inner surface of the stator and the outer surface of the rotor. Further current-carrying elements located in the interior, such as, for example, the phase switching of the stator windings or current feeds opening into the interior, are thus likewise surrounded by the fluid.This significantly improves the heat dissipation from these current-carrying parts, which are responsible for the majority of the waste heat during operation. The waste heat is thus transferred directly via the fluid (coolant) located in the interior space to the inner housing, where it can then be effectively dissipated by forced convection via the fluid (flowing coolant) which flows around the inner housing or flows along the latter. This improved heat dissipation makes it possible to further increase the power density of the electric motor and thus to improve the delivery properties of the pump without the need to increase the required structural volume for separate cooling measures (increased surfaces).In the case of an axial or semi-axial construction, the flow channel is designed as an annular gap surrounding the inner housing, which runs between the inner housing and the outer housing. The outer housing surrounds the impeller and the inner housing in such an embodiment.In one embodiment, the connection which exists between the flow channel and the interior space comprises a radially extending axial gap which is formed between the impeller and the inner housing. This embodiment enables a simple coupling of the flow channel to the interior without separate openings having to be provided in the inner housing for this purpose. Rather, a gap which is to be provided anyway for manufacturing and functional reasons serves simultaneously as a connection between the flow channel and the interior space. An axial gap running completely around the circumference also always ensures that the fluid can enter the interior space independently of the installation position of the pump.In a further embodiment, the connection comprises openings in a bearing plate which is coupled to the inner housing via an outer collar and carries a radial bearing receiving the drive shaft in a bearing sleeve. One or more bearing plates can be provided in order to realize the mounting of the drive shaft in the inner housing. In this case, the bearing plate or plates each delimit the axially opposite ends of the interior space.If the drive shaft is accommodated in rolling bearings, the fluid also enters the interior through the permeable rolling bearings. In order to improve the flooding of the interior, additional openings are provided in the bearing shield or the bearing shields. Thus, a flooding of the interior can be ensured independently of the selection of the bearing. At the same time, the weight of the bearing shield and thus of the pump is reduced.For this purpose, there is an embodiment in which the openings are arranged in a radial flange connecting the outer collar and the bearing sleeve, so that a connection with a sufficiently large cross section in the axial direction between the outer side of the bearing plate and the interior is ensured.There is an embodiment in which the loop bundles of the stator windings running outside the stator body (e.g. a stator laminated core or stator packet) are embedded (e.g. cast) in a sealing compound completely surrounding the latter. This sealing compound protects the individual loops of the loop bundles and ensures that they are protected against external influences (e.g. dirt or solids in the coolant) and remain insulated from one another. It simultaneously forms a heat transfer body (heat sink) which improves the heat transfer from the individual current-carrying conductors into the fluid surrounding the loop bundles or the sealing compound.There are embodiments where the sealant comprises a silicone material (e.g., a silicone rubber composite) that is particularly temperature resistant (up to 200° C.) and has a high thermal conductivity that is in the range of 0.6 W / m°K, and thus above that of water (~0.56 W / m°K) and far above that of air (-0.026 W / m°K).In one embodiment, the interior space is designed such that the fluid filling the interior space completely surrounds the loop bundles and thus forms a thermally conductive coupling between these and the inner housing. This design ensures that no fluid-free (optionally air-filled) dead spaces occur in the region of the loop bundles in which the heat dissipation is restricted and in which local overheating could occur.There are embodiments in which the flow channel is provided at least one guide element which connects the inner and outer housing and which has a passage which leads from radially from the outside into the interior and receives a current supply. Such, in particular helically extending, guide elements in semi-axially or axially conveying centrifugal pumps not only reduce the swirl of the conveyed fluid applied by the impeller during the conveying and thus improve the efficiency of the pump. At the same time, they make it possible in a fluidically favourable form to configure a problem-free current supply from the outside to the stator or its windings arranged in the interior. The helical arrangement also extends the flow path of the cooling medium along the inner housing and thus increases the convective heat dissipation from the inner space via the inner housing around which flow takes place.There are embodiments in which such a guide element has a profile which is thickened in some regions, for example an airfoil-like flow profile, in the front region of which (thickened) an opening which runs within this profile and leads radially into the interior space is provided. A plurality of guide elements form one or more guide mechanism arrangements which are arranged one behind the other in the flow direction.There are embodiments in which the electric motor is designed as a permanently excited EC motor which is operated via a control device with field-oriented regulation. With such motors, particularly high power densities can be achieved and they allow a particularly compact and slender and thus fluidically favorable construction of fluid pumps in an axial or semi-axial construction.There are embodiments in which the control device comprises a plurality of separate power parts, wherein a first current regulator is provided for a flux-forming component (magnetic field) and a second current regulator is provided for a torque-forming component.In addition, a logic part is optionally provided, which is designed for a control method in which rotation angle information is ascertained by means of estimated induced voltages. In this construction, no additional rotary encoder is required on the drive axle or on the rotor, which would otherwise be required for speed regulation. The operational reliability of the drive is thus improved in that an additional component which is prone to errors can be avoided.There are embodiments in which a temperature signal is used to carry out the control method in order to control the operation of the fluid pump. This is achieved by a temperature sensor optionally provided in particular in the interior of the fluid pump.In the event of overheating of the electric motor (exceeding an upper temperature threshold value), the fluid pump is switched off or its delivery volume is reduced. The pump is thus switched off or regulated as a function of the temperature. Although the delivery volume of the fluid (coolant) is reduced in this case, nevertheless cooling still takes place via the fluid located in the interior, which discharges the waste heat present to the inner housing and thus to the main coolant flow possibly circulating around the inner housing. As soon as a certain lower temperature threshold value in the interior of the housing is reached or undershot again, the fluid pump is put into operation again or its maximum delivery rate is enabled. The total delivery volume in the coolant circuit is then again completely available and is optionally then increased again in the desired manner.In a coolant delivery device which comprises a fluid pump according to the invention (optionally in addition to or as a replacement for a main pump which is fixedly coupled to the drive), the control of the coolant flow delivered by the main coolant pump can be improved considerably and the delivered coolant delivery volume can be adapted and in particular increased significantly as required, without an unnecessary power loss having to be accepted for a constantly increased delivery volume during the entire operation.An internal combustion engine with such a cooling fluid delivery device can operate more economically overall, since the additional power requirement for the additional fluid pump only has to be applied in quite specific operating ranges (high-power range). A main delivery pump can thus be designed to be more compact, lighter and with a lower power requirement. The coolant conveying device according to the invention is therefore suitable in particular for high-performance engines.Exemplary embodiments of the invention will now be described by way of example with reference to the accompanying drawings. Shown therein are: FIG. 1 shows a perspective longitudinal sectional illustration of a fluid pump according to the invention, FIG. 2 is a side view of the impeller and the nozzle assembly of the fluid pump shown in FIG. 1, FIG. 3 shows a schematic illustration of a fluid pump according to the invention in a detail from the coolant circuit of an internal combustion engine, FIG. 4A shows a perspective external view of a control unit for a fluid pump according to the invention, FIG. 4B is an inner view of the control device shown in FIG. 4A; and FIG. 5 shows a schematic illustration of an internal combustion engine with coolant delivery device.The construction and function of a fluid pump 1 according to the invention will be described below with reference to FIGS. 1 to 3.The fluid pump 1 shown in FIG. 1 comprises a housing component 2 which comprises an approximately cylindrical outer housing 3 and a likewise approximately cylindrical inner housing 4. A flow channel runs between inner housing 4 and outer housing 3, which is designed as an annular flow gap 5, and runs substantially axially along inner housing 4 from an inlet end 6 to an outlet end 7. At the inlet end 6, the outer housing 3 forms a suction opening and at the outlet end 7 a discharge opening. At the inlet end 6 and at the outlet end 7, a sealing bead 8 is formed, on which a supply and a discharge hose 10, 11 is plugged (cf. FIG. 3 ).On the intake side, an impeller (impeller 12) is provided at the end face of the inner housing 4, on the circumference of which a plurality of conveying blades 13 are arranged and which is formed on the end face towards the inlet end 6 as a curved inflow body 14, the flow contour of which merges into the outer contour of the inner housing 4.The inner housing 4 merges at its outlet end 7 into an outflow body 15 which narrows in the direction of flow. The inner housing 4 and the outflow body 15 are connected to the inner housing 4 via two guide mechanism arrangements 16A and 16B, which surround the inner housing 4 in a helical manner. In the exemplary embodiment shown, outer housing 3, inner housing 4 and outflow bodies 15 and the guide unit arrangements 16A and 16B are formed integrally as a casting, for example from a light metal material. In other embodiments, these individual assemblies are each configured individually and / or in subassemblies which are subsequently joined together.The impeller 12 is seated on a hollow shaft 18 which is accommodated at the outlet end 7 via a rolling bearing 19 (for example a grooved ball bearing) in a corresponding recess in the outflow body 15. On the shaft side, the rolling bearing is fixed on the hollow shaft 18 via a retaining screw 20, while the outer ring of the rolling bearing 19 is held in its position via a screwed closure cap 21 with a curved flow contour, which closure cap closes the bearing recess.On the intake side, the end of the hollow shaft 18 carries the impeller 12 which is axially fixed by means of a retaining screw 22 and which positions a further rolling bearing 23 which is likewise arranged on the hollow shaft 18 by means of an inwardly projecting cylindrical collar. The rolling bearing 23 is fixed on its outer ring by a bearing plate 24 with respect to the inner housing 4. The bearing shield 24 is positioned in the inner housing 4 via a collar at the inlet-side end thereof and is connected via a radial flange 26 to a bearing bush 27 in which the rolling bearing 23 is seated with its outer ring.The cavity present between the inner housing 4, the bearing shield 24 and the outflow body 15 forms the interior 17, where a rotor 29 equipped with permanent magnets 28 is formed on the hollow shaft 18. Rotor 29 and impeller 12 are connected in a force-fitting manner and thus in a rotationally fixed manner to hollow shaft 18 via tolerance rings 30.There are other embodiments in which the hollow shaft 18 or even a solid shaft with other suitable shaft-hub connections are coupled to the rotor or to the impeller 12 in a rotationally fixed manner.On the inner circumferential surface of the inner housing 4 a stator 31 is arranged in which the current-carrying windings run, wherein at the axial ends of the stator 31 loop bundles 32 project into the inner space 17. The line windings are each connected via supply lines 34 to a power supply or a controller (see FIG. 4 ) via a phase connection 33 likewise arranged in the interior 17. The feed lines 34 pass through radial openings 35 which extend from the inside in the intake-side region of the guide elements 36 radially outwards through the inner housing 4 and the outer housing 3, wherein the inner and outer housings 3, 4 are connected to one another via the guide elements 36. The radial openings 35 open on the outside into an annular groove 37 on the outer housing 3, in which the feed lines 34 are cast via a suitable sealing compound and from there lead to a power supply or to a control (cf. FIG. 5 ).Between the end face 38 on the impeller 12 facing in the axial direction (in the direction of the outlet end 7) and the opposite end face 39 of the inner housing 4, a gap extends into which a stop flange of the bearing plate 24 projects, wherein an open, radially extending axial gap 40 extends between the suction-side end face of this flange 41 and the end face 38 of the impeller 12. This axial gap 40 forms a communicating connection between the flow gap 5 and the interior 17 within the inner housing 4 over the entire circumference of the impeller 12 or that of the inner housing 4.In the interior, rotor 29 and stator 31 together with its windings, the phase interconnection 33 and the feed lines 34 form a so-called EC motor which, during operation, drives the impeller 12 coupled to the rotor 29 via the hollow shaft 18. In this case, the rotating conveying blades 13 convey the fluid entering through the suction opening at the inlet end 6 through the flow gap 5 to the outlet end 7, wherein the guide elements 36 of the guide mechanism arrangements 16A and 16B, which are arranged axially one behind the other, bring about a neutralization of the swirl which is applied via the rotating impeller 12 to the fluid which thus leaves the fluid pump 1 at the outlet end 7 through the discharge opening substantially without swirl.When the flow gap 5 is filled with the fluid to be conveyed, the fluid passes through the axial gap 40, the rolling bearing 23 and the openings 42 into the interior 17 within the inner housing 4 and completely flows through the latter. The fluid completely surrounds both the rotor 29 and the stator 31 and the phase switching 33 and the loop bundles 32. For protection and for improved heat dissipation, the loop bundles 32 are embedded in (surrounded by) a thermally conductive silicone compound, which protects the lines in the loop bundles 32 from damage (due to particles and impurities possibly present in the fluid), and improves the heat dissipation from the conductors through which electrical current flows into the fluid. The fluid thus serves as a heat transfer medium, in particular between the current-carrying parts in the interior 17 and the inner housing 4, around which the conveyed fluid flows on its outer side and there gives off heat introduced from the interior 17 into the inner housing to the circulating fluid.To improve the fluid flowing through the interior 17 in addition or as an alternative to the connection via the axial gap 40, the rolling bearing 23 and the openings 42, optional additional connections are provided on the outlet-side region of the inner housing 4. These connections are provided, for example, as radially extending openings 43--in particular slots--or as axial bores 44 in the outflow body 15. By means of such additional connections, the heat dissipation from the interior 17 can be further increased during operation. The fluid filling the interior 17 then serves not only as a heat conductor, but flows through the interior more or less quickly and thereby causes an increased convective heat transport.FIG. 3 shows an installation situation of the fluid pump 1 between a supply hose 10 and a discharge hose 11. From there, it is conveyed by the rotating impeller 12 through the flow gap 5 and the guide mechanism arrangements 16A and 16B to the outlet end 7, where it reaches a widened region 11A of the discharge hose 11 in a largely swirl-free manner and flows further there. A portion of the conveyed fluid enters the interior 17 (FIG. 1 ) through the axial gap 40, surrounds the current-carrying and thus heat-generating components and functions as a heat transfer medium between these elements and the inner housing 4, through which the heat produced can be dissipated via the fluid flowing through the flow gap 5.Due to the axial construction of the fluid pump 1, the flow properties of the entire cooling fluid delivery system are only slightly impaired even when the fluid pump 1 is at a standstill. The fluid pump 1 according to the invention can flow through it without great flow resistance even when stationary with low friction losses.The control of the fluid pump is effected via the control 50 illustrated in FIGS. 4 aand 4 b, which is connected via a plug 51 to a power supply (e.g. that of a vehicle) and via a plug 52 to the feed line or lines 34 of the fluid pump 1 (FIG. 1 ). The controller is accommodated on a printed circuit board 53 which comprises a power section 54 and a logic section 55. The power section 54 comprises an inverter (for example in the form of a B6 bridge) which generates the rotating field of the electric motor with the aid of so-called MOSFETs.Logic portion 55 includes a controller or controller that performs control of the field generating motor currents and motor speed. The logic part 55 is provided with two further terminals 56, 57 which connect the logic part to other control elements of the vehicle or of the engine.In an optional embodiment, the logic part 55 is connected to a temperature sensor 58 (FIG. 5 ), which detects the fluid temperature in the interior 17 of the fluid pump 1 and outputs a corresponding signal to the logic part 55 of the controller 50. When an upper temperature threshold value is exceeded, the rotational speed of the fluid pump 1 is then reduced to such an extent that the heat generation in the current-carrying parts, in particular in the stator 31, is likewise reduced and the fluid pump 1 can cool down more strongly during operation. When a lower threshold value of the temperature is undershot, the full power of the fluid pump 1 is then available again.The motor of the fluid pump 1 is operated, for example, in a sensorless manner-i.e. without additional rotational speed detection-with a field-oriented control (FOC). In this case, the alternating currents flowing in the (e.g. three) motor phases are transformed into two equivalent direct currents. One represents the flux-forming (magnetic field-generating) component and the other represents the torque-forming component (the movement of the rotating field around the rotor). The field and the torque can thus be regulated largely independently of one another. Alternatively, the motor control is carried out under sensor control.For this purpose, the power electronics system contains two separate current controllers, which are controlled via the logic part 55. The rotor rotational angle or the rotational angle speed is not explicitly measured in this case-a separate rotary encoder would be required for this purpose-but rather calculated from the measured currents in the individual motor phases. For example, a method is used for this purpose, in which the induced voltages are estimated. In this case, the ratio of these estimated induced voltages to one another makes it possible to determine the angle-of-rotation information necessary for field-oriented regulation (FOC). The setpoint values for reactive and active currents are predefined in a loss-optimized manner according to the so-called maximum torque-per-ampere strategy. The speed control itself can take the form of a classic PI controller which is implemented in the logic part 55.FIG. 5 shows an internal combustion engine 60 having a coolant circuit 61, the coolant delivery device comprising the fluid pump 1 and a main coolant pump 62, which is mechanically coupled to the internal combustion engine 60 and is driven by the latter. An oil heat exchanger 63 and a cooler 64 are arranged in the coolant circuit. The fluid pump 1 is supplied with the phase current via the control unit 50. An optional temperature sensor 58 in the fluid pump is connected via a control line to the control device 50, which is supplied with power (e.g. 12 V battery of the vehicle electrical system) via a power source 66. Via a further optional control line, the control device 50 is coupled to a vehicle / engine controller 65, via which further control data for the control or regulation of the fluid pump are provided.List of reference characters1 Fluid pump 2 Housing component 3 Outer housing 4 Inner housing 5 Flow gap 6 Inlet end (suction opening) 7 Outlet end (discharge opening) 8 Sealing bead 10 Feed hose 10A Widened region 11 Discharge hose 11A Widened region 12 Impeller (impeller) 13 Conveying blade 14 Inflow body 15 Outflow body 16A, 16 b.Tail unit arrangement 17 Interior 18 Hollow shaft 19 Rolling bearing 20 Retaining screw 21 Closure cap 22 Retaining screw 23 Rolling bearing 24 Bearing plate 25 Collar 26 Radial flange 27 Bearing bush 28 Permanent magnet 29 Rotor 30 Tolerance ring 31 Stator 32 Loop bundle 33 Phase interconnection 34 Feed line 35 Radial opening 36 Guide element 37 Annular groove 38 End face Impeller 39 End face Inner housing 40 Axial gap 41 Stop flange 42 Opening 43 Slot (optional) 44 Bore (optional) 50 Controller 51 Current supply 52 Feed line 53 Circuit card 54 Power part 55 Logic part 56,57 Control connection 58 Temperature sensor / sensor 59-free 60 Internal combustion engine 61 Coolant circuit 62 Main coolant pump 63 Oil heat exchanger 64 Cooler 65 Vehicle / engine controller 66 Current source

Claims

Fluid pump (1) having an inner housing (4) and an outer housing (3), wherein the inner housing (4) defines an inner space (17) in which an electric motor having a stator (31) and a rotor (29) is arranged, the rotor (29) is coupled to an impeller (12) via a drive shaft (18), the outer housing (3) surrounds the impeller (12) and the inner housing (4) and the outer housing (3) form a flow duct (5) adjoining the inner housing (4), in particular an annular flow gap which connects an inlet end and an outlet end (6, 7) which are formed in particular at axially opposite ends of the outer housing (3), wherein a connection (40; 42; 43; between the flow duct (5) and the inner space (17); 44), so that a fluid conveyed through the flow gap (5) completely fills the interior space (17), surrounds the stator (31) and the rotor (29), and the fluid improves a heat transfer between the interior space (17) and the interior housing (4).Fluid pump (1) according to claim 1, wherein the connection comprises an axial gap (40) formed between the impeller (12) and the inner housing (4).Fluid pump (1) according to claim 1 or 2, wherein the connection comprises at least one opening (42) in a bearing shield (24), which is coupled to the inner housing (4) via a collar (25) and carries a bearing (23) receiving the drive shaft in a bearing bush (27).Fluid pump (1) according to claim 3, wherein the opening (42) is arranged in a radial flange (26) connecting the collar (25) and the bearing bush (27).Fluid pump (1) according to Claim 1, 2, 3 or 4, in which the stator (31) has line developments in which loop bundles (32) running at least outside a stator body are embedded in a sealing compound, in particular a silicone compound.Fluid pump (1) according to claim 5, wherein the interior space (17) is configured such that the fluid filling the interior space (17) completely surrounds the loop bundles (32) and forms a thermally conductive coupling between these and the inner housing (4).Fluid pump (1) according to one of the preceding claims, in which at least one guide element (36) connecting inner and outer housings is provided in the flow gap (5), said guide element having a passage (35) which leads from the outside into the interior space (17) and is designed to receive a power supply (51).Fluid pump (1) according to one of the preceding claims, in which the electric motor is designed as a permanently excited EC motor which is operated via a control device (50) with field-oriented regulation.Coolant delivery device (62, 1) for an internal combustion engine (60) having a fluid pump (1) according to one of the preceding claims.Internal combustion engine (60) having a coolant delivery device according to Claim 9.

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