Fluid pump

Abstract

To provide a fluid pump of an improved or at least substituted embodiment.SOLUTION: The present invention relates to a fluid pump (1). The fluid pump (1) includes an impeller unit (2) having an impeller (4), and an electric motor (6) having a motor housing (10). The impeller unit (2) includes an inlet side (2a) having a fluid inlet (5a), and an outlet side (2b) having a fluid outlet (5b). A guide channel (26) fluidically connects the inlet side (2a) and the outlet side (2b) via the impeller (4). According to the present invention, the guide channel (26) is additionally realized in regions by a cooling fluid jacket (27) that is formed in the motor housing (10).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a fluid pump for a fuel cell system having at least one fuel cell stack of a plurality of fuel cells according to the preamble of claim 1 . [Background technology]

[0002] Fluid pumps are already known from the prior art and usually comprise an impeller for conveying a fluid and an electric motor for driving said impeller. Fluid pumps can be employed, among others, for cooling fuel cell systems. A fuel cell system then usually comprises a number of fuel cell stacks, which are cooled by the fluid conveyed by the fluid pump. During operation of the fluid pump, heat is also generated in the motor, which must be cooled. The cooling of the motor is carried out, for example, by circulating the fluid conveyed by the fluid pump directly around the stator and rotor. However, when cooling the fuel cell stacks of a fuel cell system, separate requirements exist for the fluid. In particular, the fluid should be and remain a dielectric. Due to the high ion emission, the stator and rotor cannot be directly circulated by the fluid in the fluid pump provided for the fuel cell system. A separate cooling of the motor is therefore necessary, which is complex and expensive. Summary of the Invention [Problem to be solved by the invention]

[0003] It is therefore an object of the present invention to provide an improved, or at least alternative embodiment, fluid pump, whereby the stated drawbacks are overcome. [Means for solving the problem]

[0004] According to the invention, this object is solved through the subject matter of independent claim 1. Advantageous embodiments are the subject matter of the dependent claims.

[0005] A fluid pump for a fuel cell system having at least one fuel cell stack of a plurality of fuel cells is provided. The fluid pump comprises an impeller unit with an impeller rotatable about a rotation axis and an electric motor with a motor housing. The impeller unit is arranged at an axially longitudinal end of the motor with respect to the rotation axis. The impeller unit is designed to provide a cooling fluid and the motor is designed to drive the impeller of the impeller unit. The impeller unit comprises an inlet side, i.e. a low pressure side, with a fluid inlet and an outlet side, i.e. a high pressure side, with a fluid outlet. The impeller separates the inlet side and the outlet side from each other. Furthermore, the fluid pump comprises a guide channel for the cooling fluid, which fluidly connects the inlet side and the outlet side via the impeller. According to the invention, the guide channel is additionally realized in the region by a cooling fluid jacket formed in the motor housing.

[0006] The electric motor may be constructed in any manner known to those skilled in the art, and may thus comprise a rotatable shaft defining the axis of rotation of the impeller, a rotor non-rotatably connected to the shaft, and a stator housing the rotor, and the shaft may be suitably drivingly or non-rotatably connected to the impeller.

[0007] In the fluid pump according to the invention, the motor is consequently cooled by the cooling fluid conveyed by the fluid pump. A complex and cost-intensive additional cooling of the motor can thus be avoided. The cooling fluid jacket is formed in the motor housing and is bounded by the motor housing in a liquid-tight manner to the outside, so that the cooling fluid does not come into direct contact with the further components of the motor. This makes it possible, on the one hand, to exclude ion emissions into the cooling fluid, and, on the other hand, to indirectly cool further components of the motor by the cooling fluid. In particular, a higher motor efficiency and at the same time a better cooling of the electric components of the motor (e.g. the stator) can be achieved as a result with a wet runner. In particular, the cooling fluid can be dielectric or electrically non-conductive. The cooling fluid is mainly liquid. The cooling fluid can for example be a water-containing mixture, such as a water-glycol mixture.

[0008] The cooling fluid jacket can be formed by a double-walled area at least in the area. The double-walled area can be formed at least in the area of ​​the motor housing and / or in the pot-shaped housing body of the motor housing and / or in the housing wall at the circumference of the rotation axis of the pot-shaped housing body of the motor housing and / or in the bottom part of the motor housing which closes the pot-shaped housing body transversely to the rotation axis. The double-walled area can be formed in the circumferential direction about the rotation axis, in particular completely circumferentially to the rotation axis. Thus, the motor housing can be cooled evenly in the circumferential direction about the rotation axis. The double-walled area can be formed by an outer wall and an inner wall and delimited to the outside. The inner wall can be arranged at a distance from the outer wall. The cooling fluid jacket is then arranged between the outer wall and the inner wall. The double-walled area can include at least one separation area, where by the at least one separation area individual flow passages through which the cooling fluid can flow are formed in the cooling fluid jacket and / or are fluidically separated from each other. In particular, the flow paths that can be filled by the cooling fluid can include at least one forward flow path and / or at least one return flow path and / or at least one connecting flow path. The cooling fluid jacket has a double wall structure, which allows for effective cooling of heat generating components in the fluid pump and especially in the electric motor.

[0009] The cooling fluid jacket may comprise at least one forward flow path, at least one connecting flow path and at least one return flow path. The at least one forward flow path may lead from the outlet side of the impeller unit to the at least one connecting flow path. The at least one connecting flow path may lead from the at least one forward flow path to the at least one return flow path. The at least one return flow path may lead from the at least one connecting flow path to the inlet side of the impeller unit. Thus, the at least one forward flow path merges into the at least one connecting flow path and the at least one connecting flow path merges into the at least one return flow path. In other words, the at least one connecting flow path and the at least one return flow path are fluidly connected to each other via the at least one connecting flow path. It will be appreciated that the fluid pump may comprise multiple forward flow paths and / or multiple connecting flow paths and / or multiple return flow paths. The number of forward flow paths and / or the number of connecting flow paths and / or the number of return flow paths may be the same or different. The plurality of forward flow paths and / or the plurality of connecting flow paths and / or the plurality of return flow paths may each be fluidly separated from one another or fluidly connected to one another.

[0010] The cooling fluid jacket fluidly interconnects the outlet side or high pressure side of the impeller unit with the inlet side or low pressure side of the impeller unit. The outlet side or high pressure side of the impeller unit is under higher pressure during operation of the fluid pump than the inlet side or low pressure side of the impeller unit, so that the cooling fluid in the cooling fluid jacket can be transported. In the method, the cooling fluid transported by the impeller from the inlet side to the outlet side partially flows into the fluid outlet and partially into at least one forward flow path. As at least one forward flow path, the cooling fluid further flows into at least one connecting flow path and further into at least one return flow path. From the at least one return flow path, the cooling fluid flows to the inlet side of the impeller unit and is transported again to the outlet side by the impeller. The cooling fluid jacket is thus swept by the cooling fluid transported by the impeller and can indirectly cool the electric motor or further heat-generating components of the motor.

[0011] The cooling fluid jacket may comprise a plurality of forward flow channels, where each forward flow channel is fluidly connected to the outlet side of the impeller unit via a respective inlet opening. The plurality of forward flow channels may extend axially or parallel to the rotation axis of the impeller in the motor housing. Furthermore, the plurality of forward flow channels may be formed distributed around the rotation axis in the motor housing. The inlet openings of each of the plurality of forward flow channels may thus be formed distributed around the rotation axis in the motor housing. The outlet side of the impeller unit is formed on the circumference of the impeller, and the respective inlet openings of the plurality of forward flow channels may thus be distributed around the rotation axis on the circumference of the impeller. The plurality of forward flow channels may be fluidly connected to each other. In particular, the plurality of forward flow channels may be fluidly connected to each other at circumferential bridge points on the circumference of the rotation axis. The plurality of forward flow channels may form a common overall flow channel on the circumference of the rotation axis, where in the overall flow channel the flow direction is defined by the orientation of the individual forward flow channels.

[0012] Advantageously, the cross section of the at least one forward flow passage can increase in size from the inlet side of the impeller unit to the longitudinal end of the motor arranged opposite the impeller unit. In other words, the cross section of the at least one forward flow passage can increase in size from the inlet side of the impeller unit to the longitudinal end of the motor arranged opposite the impeller unit in the axial direction. In particular, the cross section of the at least one forward flow passage can increase uniformly from the inlet side of the impeller unit to the longitudinal end of the motor arranged opposite the impeller unit. In particular, at least the forward flow passage can be formed conically. A motor housing with a forward flow passage formed in this way can be produced in a die-casting process as a one-piece part, where the increased cross section of the forward flow passage ensures the removability of the motor housing and simplifies its production.

[0013] In addition, it is conceivable that in at least one forward flow passage located opposite each other, two demolding slopes are formed, and the cross section of at least one forward flow passage does not increase from the inlet side of the impeller unit to the longitudinal end of the motor located opposite the impeller unit. Due to the forward flow passage formed in this way, the motor housing can be manufactured in two parts, in which case the demolding slopes ensure the demoldability of the individual parts of the motor housing and simplify the manufacture of the motor housing.

[0014] Alternatively, it is also conceivable that the cross section of the at least one forward flow passage does not increase from the inlet side of the impeller unit to the longitudinal end of the motor arranged opposite the impeller unit, and that no demolding ramp is formed in the at least one forward flow passage. A motor housing having a forward flow passage formed in this way can be manufactured, for example, by the lost foam casting method.

[0015] The motor housing can comprise a pot-shaped housing body, which can be open at a longitudinal end of the motor located opposite the impeller unit. Furthermore, the motor housing can comprise a bottom extending transversely to the rotation axis, which can close the pot-shaped housing body at the longitudinal end of the motor located opposite the impeller unit. Thus, an interior can be formed in the motor housing, which is bounded towards the outside by the pot-shaped housing body and the bottom. In said interior, further parts of the electric motor can be accommodated. Then, at least one forward flow passage and at least one return flow passage can be formed at least in a region in the housing body and bounded towards the outside by the housing body. Then, at least one connecting flow passage can be formed in the bottom of the motor housing.

[0016] The bottom of the motor housing can be formed by a bottom plate and a cover, which can be arranged sealingly against the bottom plate facing the impeller unit. At least one connecting channel can be formed between the bottom plate and the cover and can be delimited towards the outside by the bottom plate and the cover. Advantageously, the at least one connecting channel can be formed in a serpentine and / or labyrinth shape. Alternatively, turbulence-generating structures can be formed in the at least one connecting channel. It is also conceivable that at least one separate turbulence insert is arranged in the at least one connecting channel.

[0017] The cooling fluid jacket can be fluidly connected only with the inlet side of the impeller unit and with the outlet side of the impeller unit. The pot-shaped housing body can comprise a housing wall at the periphery of the rotation axis and a partition wall oriented transversely to the rotation axis. The partition wall can be formed integrally, in one piece, or from a piece of the housing wall. The partition wall can be arranged at a longitudinal end of the motor facing the impeller unit and can fluidly separate the interior formed in the pot-shaped housing body or in the motor housing from the impeller unit or from the inlet and outlet sides of the impeller unit. At least one forward flow passage can then be fluidly connected to the outlet side of the impeller unit via the partition wall, and at least one return flow passage can then be fluidly connected to the inlet side of the impeller unit via the partition wall.

[0018] Advantageously, the fluid pump can comprise an inverter for the energy supply of the motor. The inverter can be arranged adjacent to the cooling fluid jacket in a heat-transfer manner at a longitudinal end of the motor located opposite the impeller unit on the motor housing. Furthermore, the inverter can be indirectly cooled via the cooling fluid jacket by the cooling fluid conveyed by the impeller unit. The inverter can convert, for example, a direct current voltage of a battery into an alternating current voltage for driving the motor. The inverter can in particular comprise current-conducting components that are appropriately fluidly separated from the guide channels or the cooling fluid jacket. This allows the inverter to be suitably arranged outside the motor housing. The current-conducting components can in particular include a control board with power semiconductors (for example IGBTs), which is in turn indirectly cooled by the cooling fluid conveyed by the impeller unit.

[0019] As already mentioned, the motor may comprise a shaft, which is rotatable about a rotation axis and is drivingly connected or non-rotatably (rotatably connected) to the impeller of the impeller unit. Furthermore, the fluid pump may comprise a bearing for mounting the shaft at a longitudinal end of the motor arranged opposite the impeller unit, the bearing being arranged adjacent to the cooling fluid jacket in a heat transfer manner on the motor housing. The bearing can thus be indirectly cooled via the cooling fluid jacket by the cooling fluid conveyed by the impeller unit. In particular, the bearing can be arranged on a cover at the bottom opposite the impeller unit. Thus, on the one hand, the bearing is separated by the cover from at least one connecting channel at the bottom of the motor housing and, on the other hand, is particularly effectively cooled.

[0020] Further important features and advantages of the invention emerge from the dependent claims, the drawings and the associated drawing description by way of the drawings.

[0021] It is to be understood that the features set out above and described below may not only be used in the respective combinations described, but may also be used in other combinations or alone without departing from the scope of the invention.

[0022] Preferred exemplary embodiments of the present invention are illustrated in the drawings and will be described in more detail in the following description, where like reference numbers refer to the same, similar or functionally the same components. [Brief description of the drawings]

[0023] In each case, a schematic is shown. [Figure 1] FIG. 2 is an exploded view of a fluid pump according to the present invention. [Diagram 2] 1 is a cross-sectional view of a fluid pump according to the present invention; [Diagram 3] 2A-2C are different views of the fluid pump according to the invention; [Figure 4] 2A-2C are different views of the fluid pump according to the invention; [Diagram 5] 2A-2C are different views of the fluid pump according to the invention; [Figure 6] 2A-2C are different views of the fluid pump according to the invention; [Figure 7] 2A-2C are different views of the fluid pump according to the invention; [Figure 8] 2A-2C are different views of the fluid pump according to the invention; [Figure 9] 1 is an exploded view, with partial cross-section, of a fluid pump according to the present invention; [Figure 10] FIG. 2 is an exploded view of a housing body of the fluid pump according to the present invention. [Figure 11] FIG. 2 is a view of a housing body of the fluid pump according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] FIG. 1 shows an exploded view of a fluid pump 1 according to the invention. The fluid pump 1 is provided or designed for a fuel cell system having at least one fuel cell stack of a plurality of fuel cells. The fuel cell system can in particular be provided or designed for a commercial vehicle. The fluid pump 1 comprises an impeller unit 2 with an impeller housing 3 and an impeller 4. The impeller unit 2 comprises an inlet side 2a (i.e. low pressure side) with a fluid inlet 5a or an outlet side 2b (i.e. high pressure side) with a fluid outlet 5b. The inlet side 2a and the outlet side 2b are separated from each other by the impeller 4 or are fluidly connected to each other. The fluid inlet 5a and the fluid outlet 5b are formed in the impeller housing 3.

[0025] Furthermore, the fluid pump 1 comprises an electric motor 6, which may in particular be a permanent magnet synchronous motor. The electric motor 6 comprises a shaft 7 rotatable about a rotation axis RA, a rotor 8 rigidly connected to the shaft 7 and a stator 9 housing the rotor 8. The shaft 7 is drivingly connected to the impeller 4, so that the impeller 4 is rotatable about the rotation axis RA. The motor 6 comprises two longitudinal ends 6a and 6b, which are located opposite each other on the rotation axis RA. The impeller unit 2 is arranged at the longitudinal end 6a of the motor 6.

[0026] The motor 6 further comprises a motor housing 10 with a pot-shaped housing body 11 and a bottom part 12 transverse to the axis of rotation RA. The motor housing 10 further comprises a housing seal 13 arranged or seal-clamped between the housing body 11 and the bottom part 12, which seals the relevant joint against the outside. The housing body 11 and the bottom part 12 are screwed together by a number of housing screws 14. The housing body 11 comprises a housing wall 11a around the axis of rotation RA and a partition wall 11b extending transversely to the axis of rotation RA. The partition wall 11b fluidically separates the impeller 4 from the rotor 8 and the stator 9. The bottom part 12 consists of a bottom plate 12a and a cover 12b, which closes the bottom plate 12a on the stator side or rotor side or impeller side. A cover seal 15 is arranged or seal-clamped between the bottom plate 12a and the cover 12b, which seals the relevant joint against the outside. The bottom plate 12a and the cover 12b are screwed together by a plurality of cover screws 16.

[0027] The stator 9 is accommodated non-rotatably in a motor housing 10, and the shaft 7 together with the rotor 8 is accommodated rotatably in the motor housing 10 or in the stator 9. For this purpose, the fluid pump 1 comprises two bearings 17a and 17b which rotatably mount the shaft 7 on the respective longitudinal ends 6a and 6b of the motor 6. In addition, an impeller seal 18 is arranged on the shaft 7 at the longitudinal end 6a.

[0028] The fluid pump 1 also comprises a sliding ring seal 19, which is arranged or seal-clamped between the motor housing 10 and the impeller housing 3 and seals the associated joint against the outside. The sliding ring seal 19 is in particular made from SiC. The fluid pump 1 also comprises a U-shaped seal 20, which is likewise arranged or seal-clamped between the motor housing 10 and the impeller housing 3.

[0029] The fluid pump 1 also includes an inverter 21 for the energy supply of the motor 6. The inverter 21 can be designed, for example, to convert a DC voltage of 400 V or more and 860 V or less. The inverter 21 is also arranged on the bottom 12 at the longitudinal end 6b of the motor 6. The inverter 21 has a control board 22 and an inverter cover 23, the control board 22 being arranged between the bottom 12 or bottom plate 12a of the motor housing 10 and the inverter cover 23 facing away from the impeller unit 2, or on the outside. The inverter 21 further includes an inverter seal 24 arranged or seal-clamped between the bottom 12 or bottom plate 12a and the inverter cover 23, sealing the relevant joints towards the outside. The bottom 12 or bottom plate 12a and the inverter cover 23 are screwed together by a number of inverter screws 25.

[0030] The fluid pump 1 is designed to convey a cooling fluid, in particular a liquid. For this purpose, the fluid pump 1 comprises a guide channel 26 which runs from the fluid inlet 5a on the inlet side 2a through the impeller 4 to the fluid outlet 5b on the outlet side 2b. Furthermore, the guide channel 26 is realized in the area of ​​a cooling fluid jacket 27 formed in the motor housing 10. The cooling fluid jacket 27 comprises a number of (here seven) forward and return channels 28a and 28b in the housing body 11 and a serpentine or labyrinth-shaped connecting channel 29 between the bottom plate 12a and the cover 12b. The cooling fluid jacket 27 is delimited to the outside by the motor housing 10, so that the rotor 8 and the stator 9 are not directly contacted or flowed around by the cooling fluid. The cooling fluid itself may be dielectric. The structure of the cooling fluid jacket 27 is explained in more detail below with the aid of Figs. 9 to 11.

[0031] The fuel cell system can be provided in particular for commercial vehicles. In this case, the fluid pump 1 can be designed in such a way that one fluid pump 1 is sufficient to cool the fuel cell system, even with a multi-fuel cell stack. The fluid pump 1 can thus have a maximum power of 4000 W to 6000 W (in particular 4500 W) and / or a maximum conveying speed of 400 l / min to 700 l / min and / or a maximum pressure of 3 bar to 4 bar (in particular 3.5 bar) and / or a maximum rotational speed of 5000 / min to 6,000 / min (in particular 5,400 / min) and / or a maximum torque of 6.0 Nm to 8.0 Nm. The impeller 4 can have a maximum efficiency of 60% to 70%, in particular 65%, where the maximum value is based on full load operation of the fluid pump 1.

[0032] Fig. 2 shows a cross-sectional view of the fluid pump 1 according to the present invention. In Fig. 2, in particular, the connecting passage 29 of the cooling fluid jacket 27 can be seen between the bottom plate 12a and the cover 12b of the motor housing 10. The forward passage 28a and the return passage 28b are arranged adjacent to the connecting passage 29 adjacent to the stator 9 of the motor 6 and the control board 22 of the inverter 21, and adjacent to the bearing 17b. Therefore, the stator 9, the control board 22 and the bearing 17b can be indirectly cooled by the cooling fluid conveyed by the impeller unit 2.

[0033] Figures 3 to 8 show fluid pump 1 viewed from different directions. Figures 3 to 8 show the fluid pump in an attached state.

[0034] FIG. 9 shows a partial cross-sectional exploded view of the fluid pump 1 according to the invention, where the impeller housing 3 has been omitted for clarity. As already mentioned, the guide channel 26 connects the inlet side 2a, i.e. the low pressure side, of the impeller unit 2 with the outlet side 2b, i.e. the high pressure side, of the impeller unit 2 via the impeller 4. The impeller 4 is drivingly connected to the shaft 7 of the motor 6 and conveys the cooling fluid from the inlet side 2a to the outlet side 2b. The inlet side 2a is therefore arranged accordingly on the circumference of the impeller 4 inside the impeller 4 and the outlet side 2b. The guide channel 26 is additionally realized in the region of the cooling fluid jacket 27. The cooling fluid jacket 27 comprises a number (here seven) of forward channels 28a, return channels 28b and connecting channels 29 and is formed in the housing wall 11a and the bottom plate 12a by a double wall region 35.

[0035] Each forward flow passage 28a is formed in the housing body 11 and in the bottom plate 12a of the bottom part 12. Each forward flow passage 28a is fluidically connected to the outlet side 2b of the impeller unit 2 via a respective inlet opening 30, which is formed in the partition wall 11b of the housing body 11. Each forward flow passage 28a extends axially or parallel to the rotation axis RA in the housing body 11 or in the housing wall 11a, and its cross section increases from the longitudinal end 6a to the longitudinal end 6b of the motor 6. A plurality of forward flow passages 28a are formed in the housing body 11 distributed around the rotation axis RA and are fluidically connected to each other in the housing body 11 and in the bottom part 12 at a bridging point. In the housing body 11, the forward flow passages 28a can flow parallel to each other and axially to the rotation axis. In the bottom plate 12a of the bottom 12, a plurality of connecting channels 29 are formed in an overlapping region between the housing body 11 and the bottom 12 or an overlapping region between the housing wall 11a and the bottom plate 12a. The cover 12b of the bottom 12 is disposed outside the housing body 11 or the housing wall 11a, and is therefore disposed outside the above-mentioned overlapping region.

[0036] The connecting channel 29 is arranged between the bottom plate 12a and the cover 12b and is formed in a serpentine or labyrinth shape. The connecting channel 29 is fluidly connected to the plurality of forward channels 28a at an inlet point 31 and to the return channel 28b at an outlet point 32. The connecting channel 29 is formed in the center of the bottom plate 12a and the cover 12b and closes the bottom plate 12a regionally and centrally. In the bottom plate 12a, the plurality of forward channels 28a are arranged in the circumferential direction of the connecting channel 29.

[0037] The return channel 28b is formed in the housing body 11 and in the bottom plate 12a of the bottom part 12. The return channel 28b is fluidly connected to the inlet side 2a of the impeller unit 2 via an outlet opening 33, which is formed in the partition wall 11b of the housing body 11. The return channel 28b extends axially or parallel to the rotation axis RA in the housing body 11 or in the housing wall 11a, and its cross section increases from the longitudinal end 6a to the longitudinal end 6b of the motor 6. At the bottom plate 12a of the bottom part 12, the return channel 28b on the outlet point 32 is fluidly connected to the connecting channel 29.

[0038] In the fluid pump 1, the cooling fluid is delivered by the impeller 4 from the fluid inlet 5a at the inlet side 2a to the fluid outlet 5b at the outlet side 2b. From the outlet side 2b, part of the cooling fluid leaves the fluid pump 1 through the fluid outlet 5b, and part of the cooling fluid flows into the cooling fluid jacket 27. In the cooling fluid jacket 27, the cooling fluid is delivered through the inlet opening 30 into the forward flow passage 28a and further into the connecting flow passage 29. The cooling fluid then enters the connecting flow passage 29 at the inlet point 31 and flows to the outlet point 32. At the outlet point 32, the cooling fluid flows into the return flow passage 28b, through the return flow passage 28b and further through the outlet opening 33 into the inlet side 2a. From the inlet side 2a, the cooling fluid flows into the fluid pump 1 through the fluid inlet 5a and is again transported by the impeller 4 to the outlet side 2b.

[0039] 10 shows an exploded view of the bottom 12 of the motor housing 10 of the fluid pump 1 according to the invention. Here it can be seen that the cover 12b closes the bottom plate 12a approximately in the middle. Furthermore, the separation area 34, which separates the forward flow path 28a and the return flow path 28b in a liquid-tight manner, can be seen in the double wall area 35.

[0040] 11 shows the housing body 11 of the fluid pump 1 according to the invention in a view looking away from the impeller unit 2. Here, in particular the inlet opening 30 leading from the return flow passage 28b into the forward flow passage 28a and into the outlet opening 33 can be seen.

Claims

1. A fluid pump (1) for a fuel cell device having a plurality of fuel cell stacks, comprising: The fluid pump (1) includes an impeller (4) rotatable around a rotation axis (RA) and an electric motor (6) that drives the impeller (4) and has a motor housing (10); an impeller unit (2) is arranged at the longitudinal end (6a) in the axial direction relative to the rotation axis (RA); The impeller unit (2) has an inlet side (2a) with a fluid inlet (5a) and an outlet side (2b) with a fluid outlet (5b), The impeller 4 separates the inlet side (2a) and the outlet side (2b), The fluid pump (1) has a guide flow path (26) for a cooling fluid, The guide flow path (26) fluidly connects the inlet side (2a) and the outlet side (2b) via the impeller (4), The guide flow path (26) is additionally formed within a region by a cooling fluid jacket (27) formed within the motor housing (10). A fluid pump (1) characterized in that:

2. the cooling fluid jacket (27) is formed at least in a region by a double-walled region (35); The double-walled region (35) comprises at least: in the motor housing (10) and / or in the pot-shaped housing body (11) of the motor housing (10) and / or in the housing wall (11a) of the pot-shaped housing body (11) of the motor housing (10) around the rotation axis (RA) and / or In the bottom (12) of the motor housing (10) which closes the pot-shaped housing body (11) transversely to the rotation axis (RA) formed in the area of, and / or said double-walled area (35) being formed around the periphery of said axis of rotation (RA) and being completely circumferential with respect to said axis of rotation (RA); and / or the double-walled region (35) is formed by an outer wall and an inner wall spaced apart from and bounded outwardly by the outer wall; and / or The double-walled region (35) includes at least one separation region (34) that is fluidly separated from each other within the double-walled region (35) of the cooling fluid jacket (27) that can be flowed by the cooling fluid.

2. The fluid pump according to claim 1, wherein:

3. the cooling fluid jacket (27) includes at least one forward flow passage (28a), at least one connecting flow passage (29), and at least one return flow passage (28b); and The at least one forward flow passage (28a) leads from the outlet side (2b) of the impeller unit (2) to at least one connecting flow passage (29), said at least one connecting flow path (29) leading from said at least one forward flow path (28a) to at least one return flow path (28b); The at least one return flow path (28b) leads from the at least one connecting flow path (29) to the inlet side (2a) of the impeller unit (2).

2. The fluid pump according to claim 1, wherein:

4. the cooling fluid jacket (27) comprises a plurality of forward flow passages (28a); each of the forward flow passages (28a) is fluidly connected to the outlet side (2b) of the impeller unit (2) via an inlet opening (30) and is connected to form a common flow passage at the longitudinal end (6b) of the electric motor (6) facing away from the impeller unit (2); 4. The fluid pump according to claim 3, wherein the fluid pump comprises:

5. the cross section of at least one forward flow passage (28a) increases from the inlet side (2a) of the impeller unit (2) to the longitudinal end (6b) of the motor (6) located opposite the impeller unit (2); 4. The fluid pump according to claim 3, wherein the fluid pump comprises:

6. The motor housing (10) has a pot-shaped housing body (11), The housing body (11) is open at a longitudinal end (6b) of the electric motor (6) and is disposed opposite the impeller unit (2); The motor housing (10) has a bottom (12) extending transversely to the rotation axis (RA), The bottom (12) closes the housing body (11) at a longitudinal end (6b) of the motor (6) arranged opposite the impeller unit (2); the at least one forward flow passage (28a) and the at least one return flow passage (28b) are formed at least in a region within the housing body (11) and are bounded to the outside by at least the housing body (11); At least one connecting passage (29) is formed in the bottom (12) of the motor housing (10).

4. The fluid pump according to claim 3, wherein the fluid pump comprises:

7. The bottom (12) of the motor housing (10) is formed by a bottom plate (12a) and a cover (12b), the cover (12b) faces the impeller unit (2) and is sealed to the bottom plate (12a); The at least one connecting channel (29) is formed between the bottom plate (12a) and the cover (12b) and is bounded to the outside by the bottom plate (12a) and the cover (12b).

7. A fluid pump according to claim 6.

8. At least one connecting channel (29) is formed in a serpentine and / or labyrinth shape, or The at least one connecting channel (29) is provided with turbulation structures, or At least one separate turbulence insert is arranged in said at least one connecting channel (29).

4. The fluid pump according to claim 3, wherein the fluid pump comprises:

9. The fluid pump (1) comprises an inverter (21) for supplying energy to the electric motor (6); the inverter (21) is disposed adjacent to the cooling fluid jacket (27) in a heat transfer manner at a longitudinal end (6b) of the electric motor (6) located opposite the impeller unit (2) of the motor housing (10); and The inverter (21) can be indirectly cooled by the cooling fluid conveyed by the impeller unit (2) via the cooling fluid jacket (27).

2. The fluid pump according to claim 1, wherein:

10. The electric motor (6) has a shaft (7), and the shaft (7) is rotatable about a rotation axis (RA) that is drivingly connected to the impeller (4) of the impeller unit (2); The fluid pump (1) includes a bearing (17b) for mounting the shaft (7) at a longitudinal end (6b) of the electric motor (6) located opposite the impeller unit (2); the bearing (17b) is thermally disposed on the motor housing (10) and adjacent to the cooling fluid jacket (27); The bearing (17b) can be indirectly cooled by the cooling fluid conveyed by the impeller unit (2) via the cooling fluid jacket (27).

2. The fluid pump according to claim 1, wherein:

11. The electric motor (6) has a shaft (7), and the shaft (7) is rotatable about a rotation axis (RA) that is drivingly connected to the impeller (4) of the impeller unit (2), The fluid pump (1) includes a bearing (17b) for mounting the shaft (7) at a longitudinal end (6b) of the electric motor (6) located opposite the impeller unit (2); the bearing (17b) is thermally disposed on the motor housing (10) and adjacent to the cooling fluid jacket (27); the bearing (17b) can be indirectly cooled by the cooling fluid conveyed by the impeller unit (2) through the cooling fluid jacket (27); The bearing (17b) is disposed on the cover (12b) of the bottom (12) and faces the impeller unit (2).

8. A fluid pump according to claim 7.

Images