Fluid pump with an axial synchronous reluctance motor

Abstract

The invention relates to a fluid pump (1) for pumping a liquid, comprising an axial synchronous reluctance motor (2). The reluctance motor (2) has a rotor (5) with recesses (11) and forms a pump impeller (12) of the fluid pump (1).

Description

[0001] FLUID PUMP WITH AN AXIAL SYNCHRONOUS RELUCTANCE MOTOR

[0002] The invention relates to a fluid pump with an axial synchronous reluctance motor according to the preamble of claim 1.

[0003] A fluid pump typically comprises a motor—for example, a reluctance motor—and an impeller for pumping a fluid. The motor typically comprises a shaft rotatable about a rotational axis, a rotor connected to the shaft in a rotationally fixed manner, and a stator. To pump the fluid, the shaft of the reluctance motor is connected to the impeller, so that when the shaft or rotor rotates, the impeller rotates along with it, pumping the fluid. Such a fluid pump requires additional installation space in the axial direction.

[0004] The object of the invention is therefore to provide an improved or at least alternative embodiment for a fluid pump of the generic type, in which the described disadvantages are overcome.

[0005] This object is achieved according to the invention by the subject matter of independent claim 1. Advantageous embodiments are the subject matter of the dependent claims.

[0006] The present invention is based on the general idea of ​​integrating a pump or impeller directly into the rotor of an axial synchronous reluctance motor.

[0007] The invention relates to a fluid pump for conveying a liquid with an axial synchronous reluctance motor. The reluctance motor comprises a shaft rotatable about a rotational axis, a rotor, and a stator. The rotor is rotationally fixedly connected to the shaft and is coaxially aligned with the stator and arranged axially adjacent. The rotor of the reluctance motor further comprises at least one recess formed in the rotor for influencing a magnetic flux. According to the invention, at least one of the recesses in the rotor of the reluctance motor is shaped such that the rotor forms an impeller of the fluid pump for conveying the liquid.

[0008] In the fluid pump according to the invention, the rotor of the reluctance motor fulfills two functions: firstly, the rotor interacts with the stator and generates torque, and secondly, the rotor also forms the impeller for pumping the fluid. This eliminates the need for a separate or additional impeller in the fluid pump according to the invention, so that the fluid pump is designed to save space in the axial direction. Furthermore, the number of components and thus also the amount of materials used in the fluid pump can be reduced. This allows both the cost and weight of the fluid pump to be reduced. Furthermore, the pumped fluid can effectively cool the reluctance motor.

[0009] The fluid pump can have an axial inlet channel for guiding the fluid to the impeller. The inlet channel can be formed in the shaft and fluidically connected to all of the recesses in the rotor that form the impeller. The fluid pump can have an outlet chamber for conveying the fluid pumped by the impeller. The outlet chamber can be arranged around the rotor of the reluctance motor and fluidically connected to all of the recesses in the rotor that form the impeller. In the fluid pump, the fluid can then flow axially via the inlet channel to the recesses that form the impeller and, as the rotor rotates, be conveyed radially outwards via the recesses that form the impeller. The fluid can then flow from the recesses that form the impeller into the outlet chamber and be conveyed further.

[0010] At least one of the recesses in the rotor forming the impeller can lead from the shaft to an outer surface of the rotor that revolves around the axis of rotation. In particular, at least one of the recesses in the rotor forming the impeller can lead from the shaft to an outer surface of the rotor that revolves around the axis of rotation at an angle of less than 90° to the axis of rotation or can be inclined to the axis of rotation. At least one of the recesses in the rotor forming the impeller can be shaped in the form of a gap leading from the shaft to an outer surface of the rotor that revolves around the axis of rotation. In other words, at least one of the recesses in the rotor forming the impeller can be shaped like a gap. The efficiency of the fluid pump can be optimized or increased by the aforementioned configurations of the recesses forming the impeller.Furthermore, the compromise between the electromagnetic properties of the rotor and the hydraulic properties of the impeller can be optimized.

[0011] At least one of the recesses in the rotor forming the impeller can have at least one support web oriented perpendicular to its direction of extension. The support web can be arranged in the recess such that the walls surrounding the respective recess in the rotor or impeller are supported against one another. This can support the respective recess and ensure a constant flow-through cross-section of the recess. The support web can therefore positively influence the hydraulic properties of the impeller or the pumping action of the impeller. In one possible embodiment of the fluid pump, it is conceivable that some of the recesses in the rotor form the impeller and some of the recesses in the rotor are designed exclusively to influence the magnetic flux in the rotor.The recesses that do not form the impeller may, for example, not be fluidically connected to the inlet channel and / or the outlet chamber. However, the recesses that do not form the impeller may improve the electromagnetic properties of the rotor and be designed accordingly. The recesses in the rotor that do not form the impeller may, for example, be filled with a dielectric material, preferably plastic.

[0012] In one possible embodiment of the fluid pump, the rotor can have at least two groups consisting of at least one recess forming the impeller. All groups can be arranged evenly distributed around the axis of rotation. This allows the impeller to be rotationally symmetrical, and the pumping effect of the impeller can be improved by the even distribution of the pumped fluid in the direction of rotation surrounding the axis of rotation.

[0013] Each group can in particular have at least two recesses forming the impeller. The recesses of the respective group can be parallel to one another and axially adjacent. The group comprising several recesses can contribute to improving the hydraulic properties of the impeller or the pumping action of the impeller. For example, the recesses of the respective group can have an identical shape to one another and increase or decrease in size along the axis of rotation. The recesses of the respective group can, for example, be distributed over the entire axial height of the rotor. Through these configurations of the recesses of the respective group forming the impeller, the hydraulic properties of the impeller can be further improved.

[0014] In the context of the present invention, the terms “axial” and “radial” and “rotating” as well as “axial direction” and “radial direction” and “rotating direction” always refer to the axis of rotation of the shaft of the reluctance motor.

[0015] Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures based on the drawings.

[0016] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0017] Preferred embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components.

[0018] They show, schematically

[0019] Fig. 1 is an exploded view of a fluid pump according to the invention with a rotor forming a pump wheel;

[0020] Fig. 2 shows a view of the rotor of the fluid pump according to the invention in a first embodiment; Fig. 3 shows a sectional view of the rotor of the fluid pump according to the invention in a second embodiment;

[0021] Fig. 4 is a view of the rotor of the fluid pump according to the invention in the second embodiment.

[0022] Fig. 1 shows an exploded view of a fluid pump 1 according to the invention for pumping a liquid. The fluid pump 1 comprises an axial synchronous reluctance motor 2 and a housing 3. The reluctance motor 2 has a shaft 4 rotatable about a rotation axis RA and a rotor 5.

[0023] The rotor 5 is aligned coaxially with the shaft 4 and connected to the shaft 4 in a rotationally fixed manner. Furthermore, the reluctance motor 2 comprises a stator 6 with windings 7, which is arranged coaxially and axially adjacent to the rotor 5. The reluctance motor 2 further comprises two bearings 8a and 8b, which rotatably support the shaft 4. The housing 3 of the fluid pump 1 comprises a hollow cylindrical housing body 9 and two covers 10a and 10b. The reluctance motor 2 is coaxially accommodated in the housing body 9, and the housing body 9 is axially closed on both sides with the covers 10a and 10b.

[0024] The rotor 5 comprises a plurality of gap-like recesses 11 which lead from the shaft 4 to an outer surface 5a of the rotor 5 which circumferentially rotates around the rotation axis RA. The rotor 5 forms an impeller 12 of the fluid pump 1. The shaft 4 has an axially aligned inlet channel 13 and the fluid pump 1 has an outlet chamber 14 formed between the housing 3 or the housing body 9 and the rotor 5. In the fluid pump 1, the liquid can flow via the inlet channel 13 to the rotor 5 or the impeller 12 and can then be pumped radially outwards into the outlet chamber 14 via the recesses 11 of the rotor 5 or the impeller 12. As a result, no additional impeller is required in the fluid pump 1 and the fluid pump 1 can be designed to be particularly space-saving in the axial direction.

[0025] The rotor 5 of the reluctance motor 2 can, for example, be formed from a soft magnetic material with high permeability or a so-called SMC material (SMC: Soft Magnetic Composite). The rotor 5 can, for example, have a layered structure in which layers of the soft magnetic material and layers of a dielectric material alternate in an axial direction or along the rotation axis RA. The layers of the dielectric material can, in particular, reduce the formation of eddy currents. Such a rotor 5 can, for example, be manufactured using a sintering process. Recesses 11 in the rotor 5 can be manufactured during the manufacture of the rotor 5. Alternatively, the rotor 5 can be formed from a wound electrical steel sheet. The electrical steel sheet can be wound onto the shaft 4.To reduce the formation of eddy currents, the electrical steel sheet can have an electrically insulating coating. The recesses 11 in the rotor 5 can be prefabricated in the electrical steel sheet, for example, by punching. It is understood that the recesses 11 in each winding of the electrical steel sheet are shaped differently or are formed or punched offset from one another.

[0026] Fig. 2 shows a view of the rotor 5 of the fluid pump 1 according to the invention in a first embodiment. The recesses 11 lead from the shaft 4 to the outer surface 5a of the rotor 5 at an incline or at an angle of less than 90° to the rotation axis RA. Here, the rotor 5 has a total of four groups 15, each with three recesses 11. The recesses 11 are arranged parallel and axially adjacent to one another in the respective group 15. The recesses 11 have an identical shape but a different size. The groups 15 are arranged in the rotor 5 and evenly distributed around the rotation axis RA.

[0027] Fig. 3 shows a sectional view of the rotor 5 of the fluid pump 1 according to the invention in a second embodiment. Fig. 4 shows a view of the rotor 5 of the fluid pump 1 according to the invention in the second embodiment. Here, the rotor 5 has a total of four groups 15, each with a recess 11 that extends from the shaft 4 to the outer surface 5a of the rotor 5 at an angle of less than 90° to the rotation axis RA. The groups 15 are shaped in the same way, evenly distributed around the rotation axis RA.

[0028] In each of the above-described embodiments of the rotor 5, in addition to the recesses 11 shown for forming the impeller 12, further recesses 11 can also be provided exclusively for influencing a magnetic flux in the rotor 5. The recesses 11 forming the impeller 12 can be shaped or configured accordingly to improve the hydraulic properties of the impeller 12. The recesses 11 not forming the impeller 12 can be shaped or configured to improve the electromagnetic properties of the rotor 5. The recesses 11 not forming the impeller 12 do not have to be fluidically connected to the inlet channel 13 and the outlet chamber 14 and can also be filled with a dielectric material—for example, plastic.It is understood that a compromise must always be chosen between the hydraulic properties and the electromagnetic properties in the number and / or arrangement and / or design and / or function of the recesses 11.

[0029] *****

Claims

Claims 1. Fluid pump (1) for pumping a liquid, - wherein the fluid pump (1) comprises an axial synchronous reluctance motor (2) with a shaft (4) rotatable about a rotation axis (RA), a rotor (5) and a stator (6), - wherein in the reluctance motor (2) the rotor (5) is connected to the shaft (4) in a rotationally fixed manner and is coaxially aligned with the stator (6) and arranged axially adjacent, and - wherein the rotor (5) of the reluctance motor (2) has at least one recess (11) for influencing a magnetic flux and the recess (11) is formed in the rotor (5), characterized in that at least one of the recesses (11) of the rotor (5) of the reluctance motor (2) is shaped such that the rotor (5) forms a pump wheel (12) of the fluid pump (1) for conveying the liquid.

2. Fluid pump (1) according to claim 1, characterized in - that the fluid pump (1) has an axial inlet channel (13) for guiding the liquid to the pump wheel (12) and the inlet channel (12) is formed in the shaft (4), and - that the inlet channel (13) in the shaft (4) is fluidically connected to all recesses (11) of the rotor (5) forming the pump wheel (12).

3. Fluid pump (1) according to claim 1 or 2, characterized in - that the fluid pump (1) has an outlet chamber (14) for conveying the liquid pumped by the pump wheel (12) and the outlet chamber (14) is arranged around the rotor (5) of the reluctance motor (2), and - that the outlet chamber (14) is fluidically connected to all recesses (11) of the rotor (5) forming the pump wheel (12).

4. Fluid pump (1) according to one of the preceding claims, characterized in that - that at least one of the recesses (11) of the rotor (5) forming the pump wheel (12) leads from the shaft (4) to an outer surface (5a) of the rotor (5) surrounding the rotation axis (RA), and / or - that at least one of the recesses (11) of the rotor (5) forming the pump wheel (12) leads from the shaft (4) to an outer surface (5a) of the rotor (5) surrounding the rotational axis (RA) at an angle of less than 90° to the rotational axis (RA), and / or - that at least one of the recesses (11) of the rotor (5) forming the pump wheel (12) is shaped in the form of a gap leading from the shaft (4) to an outer surface (5a) of the rotor (5) surrounding the rotation axis (RA).

5. Fluid pump (1) according to one of the preceding claims, characterized in that some of the recesses (11) of the rotor (5) form the pump wheel (12) and some of the recesses (11) of the rotor (5) are designed exclusively to influence the magnetic flux in the rotor (5).

6. Fluid pump (1) according to claim 5, characterized in that the recesses (11) of the rotor (5) which do not form the pump wheel (12) are filled with a dielectric material, preferably with plastic.

7. Fluid pump (1) according to one of the preceding claims, characterized in that at least one of the recesses (11) of the rotor (5) forming the pump wheel (12) has at least one support web oriented perpendicular to its direction of extension.

8. Fluid pump (1) according to one of the preceding claims, characterized in that - that the rotor (5) has at least two groups (15) of at least one recess (11) forming the pump wheel (12), and - that all groups (15) are evenly distributed around the axis of rotation (RA).

9. Fluid pump (1) according to claim 8, characterized in that - that each group has at least two recesses (11) forming the pump wheel (12), and - that the recesses (11) of the respective group (15) are formed parallel to one another and axially adjacent.

10. Fluid pump (1) according to claim 9, characterized in - that the recesses (11) of the respective group (15) have an identical shape to one another and increase or decrease in size along the axis of rotation (RA), and / or - that the recesses (11) of the respective group (15) are arranged distributed over the entire axial height of the rotor (5).

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