Axial, mixed or radial fans with hub contour

Abstract

An axial, mixed flow or radial fan has an impeller driven by an outer rotor electric motor, the impeller including a hub ring rotationally fixedly connected to the rotor and supporting the blades, a hub profile on the inlet side of the hub ring, the hub profile including an outer flow guiding surface for guiding the flow, and a central inner opening radially inwardly adjacent the outer flow guiding surface, the inner surface of the hub profile facing the rotor.

Description

[Technical field]

[0001] The present invention relates to an axial, mixed flow or radial fan having an impeller driven by an external rotor electric motor, the impeller including a hub ring supporting the blades, the hub ring being rotationally fixedly connected to the rotor of the motor. [Background technology]

[0002] Axial, mixed flow and radial fans are known in practice in a variety of designs. See, for example, US Pat. No. 5,399,633. It has been found in practice that aerodynamically shaped inlet profiles at the hub region of the impellers of axial, mixed or radial designs of fans can provide high efficiency while at the same time providing low acoustic power levels. Such inlet profiles obstruct the inlet area of ​​the engine or rotor and therefore impede engine cooling. This can reduce engine performance and even damage the bearings. In either case, high fan efficiency and low acoustic power levels must be achieved while simultaneously providing sufficient cooling for the motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] DE 102015216579(A1) Summary of the Invention [Problem to be solved by the invention]

[0004] It is therefore an object of the present invention to design and develop a fan having an aerodynamically shaped inlet profile to facilitate achieving high efficiency and low acoustic power levels while ensuring sufficiently good motor cooling. [Means for solving the problem]

[0005] According to the invention, this object is achieved by the features of claim 1, whereby in a universal fan, a hub profile is provided on the inlet side of a hub ring, said hub profile comprising an outer flow guiding surface for guiding the flow and a central inner opening radially inwardly adjacent to said outer flow guiding surface, the inner surface of which is directed towards the rotor.

[0006] The present invention provides a combination of an aerodynamic inlet profile and a sufficiently good cooling function for the rotor of an external rotor motor. The external rotor motor may be an EC (electronically commutated) synchronous motor, advantageously having a permanent magnet rotor, or an AC (alternating current) asynchronous motor. Fans with external rotor motors can be designed to be compact in the axial direction and still ensure or improve the technically important cooling of the rotor of the external rotor motor. This allows a higher transport medium temperature and / or a higher motor power and / or drive torque at the same transport medium temperature.

[0007] Cooling of the engine is achieved by a hub profile on the inlet side of the hub ring. At least, cooling is not significantly compromised compared to a non-aerodynamically shaped hub region having a central inner opening. The hub profile design ensures adequate cooling. In particular, the provision of an outer flow guiding surface for guiding the flow, a central inner opening radially inwardly adjacent to this outer flow guiding surface, and an inner surface directed towards the rotor, on the one hand, favorable flow conditions are achieved and, on the other hand, sufficient cooling of the rotor by the intake air flowing around it is ensured.

[0008] The hub profile can be achieved through a variety of design prescriptions. For example, the hub profile can be integrated in one piece with the hub ring of the impeller. The integral construction is particularly advantageous in the case of plastic parts.

[0009] The impeller can be attached to the rotor by a threaded connection via an integrated hub profile. This allows for easier handling.

[0010] It is also contemplated that the hub profile may be designed as a separate part and then plugged, clipped or otherwise attached to the impeller in a form-fit, force-fit and / or material-fit manner. Ease of assembly is always an advantage.

[0011] Furthermore, it is also conceivable for the hub profile to have active air guiding elements. This aspect also promotes the flow of coolant around the rotor bell of an external rotor motor. Furthermore, it is advantageous if the outer flow-guiding surface of the hub profile is free of steps, edges, creases and the like. The outer flow guiding surface therefore merges approximately tangentially with the outer contour of the impeller hub ring, which is aerodynamically and aeroacoustically advantageous.

[0012] In contrast, the flow-guiding outer surface of the hub profile has a sharp or rounded transition, preferably a kind of bend, with the inner surface of the hub profile on the side of the central inner opening, which also promotes the flow around the rotor bell.

[0013] It is further advantageous if, in particular in the case of rotors which protrude beyond the hub profile towards the inlet side, a number of resilient vanes are provided in the hub profile, preferably on the inner surface of the hub profile. These vanes fit tightly against the rotor surface, even when rotors of slightly different diameters are used, and can also be understood as guide elements.

[0014] It is also conceivable that the central inner opening of the hub profile has a flow-influencing structure, preferably a regular or irregular, or symmetric or asymmetric lattice structure, formed around the periphery of the rotor bell. It is important to note that it is not necessary for the central inner opening to be completely free of components. Conversely, measures that influence the flow can also be implemented there.

[0015] The aforementioned structures or lattice structures can be arranged and designed to extend to the outer flow guiding surface of the hub contour, which also promotes flow towards the rotor bell.

[0016] There are various possibilities for advantageously designing and refining the teachings of the present invention. For this purpose, reference should be made, on the one hand, to the claims dependent on claim 1 and, on the other hand, to the following description of an embodiment of a hub profile according to the invention or of a fan having this hub profile according to the invention, with reference to the drawings. In describing the embodiments of the present invention with reference to the drawings, the embodiments and improvements are also generally described. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 shows a perspective view obliquely from the inlet side of a fan with an embodiment of an aerodynamically designed hub profile open on the inlet side, the hub profile being designed as a separate part for mounting on the impeller. [Diagram 2] 2 is a cross-sectional view of the fan of FIG. 1 as viewed from the side, taken along a plane passing through the rotation axis of the impeller. [Diagram 3] FIG. 1 shows efficiency curves as a function of volumetric flow rate for a fan with and without an aerodynamically designed hub profile, for a constant impeller speed. [Figure 4] FIG. 1 shows curves of sound power level as a function of volumetric flow rate for fans with and without an aerodynamically designed hub profile for constant impeller speed. [Diagram 5] FIG. 2 is an oblique view from the inlet side showing a fan with an open inlet side and an aerodynamically designed hub profile, which is integrated into the conical hub of the impeller. [Figure 6] 6 is a cross-sectional view of the fan of FIG. 5 taken from the side along a plane passing through the rotation axis of the impeller. [Figure 7] FIG. 1 is an oblique view from the inlet side showing a fan with an open inlet side and an aerodynamically designed hub profile, which is integrated into a conical hub and has an inlet grille integrated into the hub profile. [Figure 8] FIG. 1 is an oblique perspective view from the inlet side showing a fan with an open inlet side and an aerodynamically designed hub profile, which is integrated into the conical hub of the impeller, with internal cooling flow elements integrated into the hub profile. [Figure 9] FIG. 1 shows a perspective view obliquely from the inlet side of a fan with an open inlet side and an aerodynamically designed hub profile, which is designed as a separate part for mounting on the impeller. [Figure 10] 10 is a cross-sectional view of the fan of FIG. 9 taken from the side along a plane passing through the rotation axis of the impeller. [Figure 10b] FIG. 11 is an enlarged detail of the area of ​​the hub profile of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] FIG. 1 shows, in an oblique perspective view from the inlet side, a fan 1 having an open inlet side and an aerodynamically designed hub contour 2, which is designed as a separate part for mounting on a hub ring 10 of an impeller 3. The impeller 3 is comprised of a hub ring 10 as well as blades 9 attached thereto and extending radially outwardly. The outer ends of the blades 9 are formed with special shapes 22, called winglets, which are advantageous in reducing the noise of the fan 1 during operation.

[0019] The impeller 3 of the fan 1 is driven by a motor 4 and is attached to a rotor 11 of the motor 4 . The motor 4 includes a stator 12 mounted in a housing 13 having guide vanes 14 which support the motor 4 together with the impeller 3 . The impeller 3 operates inside a housing 13 having an integral inlet nozzle 5 through which a main flow is drawn during operation of the fan 1, after which it passes through the impeller 3, guide vanes 14 or through a cylindrical section 20 and a radially enlarged section 21 (see also FIG. 2) of the housing 13 for further transport to the outlet side of the fan 1. The housing 13 is manufactured by plastic injection moulding and has various fixing means integrated therein. The various fastening means are namely a fastening device 18 for the inlet grid, a fastening device 19 for the outlet grid and fastening means 16, 17 for fastening the housing 13 to the system on the inlet and outlet sides. Furthermore, in the region of the diameter expansion 21 (see also FIG. 2 ), demolding areas 26 can be seen both on the inside and on the outside, with the aim of making it easier to demold the housing 13 in the region of the guide vanes 14 of the diameter expansion 21 due to a wall thickness distribution of the components that is favorable from the point of view of plastics technology. The release area 26 formed in the suction side area of ​​the guide vane 14 appears as a concave portion on the outer surface of the diameter expansion portion 21 and as a convex portion on the inner surface thereof, compared to the shape of the periphery of the diameter expansion portion 21.

[0020] The hub contour 2, attached to the inlet hub ring 10, has an outer flow guide surface 7 which restricts the main airflow carried by the fan 1 inwardly towards the axis. The outer flow guiding surface 7 is designed to be aerodynamically and aeroacoustically advantageous, thus positively affecting the air output, efficiency and smooth operation of the fan 1 during operation. The outer flow guide surface 7 is free of steps, edges or creases and merges approximately tangentially with the outer contour of the hub ring 10 of the impeller 3 . The outer flow guide surface 7 is designed such that from its inlet end, on the hub side, the flow passage of the main flow of the fan is continuously tapered in the axial direction. Thus, its outer diameter increases monotonically in the inlet region and the rate of increase decreases in the flow direction. By way of example, the outer flow-guiding surface 7 of the hub profile 2 may have, in cross section on a plane passing through the axis, the shape of a conic section, in particular an ellipse or a parabola. The outer flow-guiding surface 7 of the hub profile 2 has the shape of a solid of revolution. In general, however, they may be designed in different shapes.

[0021] It is important that the hub contour 2 does not unduly block or impede the flow around the rotor 11 of the motor 4 by the conveying medium entering the fan 1 through the inlet nozzle 5 . This is because dissipating heat through the rotor 11 is essential for effective cooling of the motor 4 . If there is good flow around the rotor 11, a significant amount of heat can be transferred to the transport medium. To ensure flow around the rotor 11, the hub profile 2 is designed to be open on the inside. In the embodiment, a central inner opening 6 is provided. The central inner opening 6 is arranged radially inside an outer flow-guiding surface 7 of the hub contour 2 . The incoming transport medium flows directly around the rotor 11 of the motor 4 and can release waste heat.

[0022] The hub profile 2 has, viewed radially, two regions: an inner region (in the embodiment, the region of the central inner opening 6) which is primarily allocated to engine cooling, and a radially outer region (the region of the flow guiding outer surface 7) which is allocated to the main conveying flow. In the embodiment, the boundary of the central inner opening 6 of the hub profile 2 is designed to have an acute angle towards the outside, but it may also have a rounded shape.

[0023] FIG. 2 is a cross-sectional view of the fan 1 of FIG. 1 as viewed from the side, taken along a plane passing through the rotation axis of the impeller 3. As shown in FIG. In addition to the above description, in particular the shape of the hub profile 2 is shown in cross section and characteristic dimensions are also given. The hub profile 2 therefore has a maximum outer diameter Da32, which is the radially outer boundary of the hub profile 2. In an embodiment, the maximum outer diameter Da32 may be defined by the outer boundary of a separate part that is usable for the hub ring 10 of the impeller 3 and that forms the hub contour 2. In particular, when the hub profile 2 is integrated into the impeller 3 together with the hub ring 10, the maximum outer diameter Da32 can be defined at the axial position of the flow-guiding outer surface 7 of the hub profile 2, at which the vanes 9 extend from the hub ring 10. Furthermore, the maximum outer diameter Da32 can also be defined by the axial position at which a tangent to the outer flow guiding surface 7, coming from the inlet side, first becomes approximately parallel to the axis.

[0024] Furthermore, the hub profile 2 has an inner diameter Di31, which in this embodiment is the smallest diameter of the hub profile 2. This inner diameter Di31 is comparable to the outer diameter of the front part (in particular the rotor bell) of the rotor 11 of the motor 4, so that the cooling conveying medium flows in this area of ​​the motor 4 or at least to a large extent around this area. The hub profile 2 extends axially forwards towards the inlet side beyond the rotor 11 of the motor 4 . This may also be the other way around, i.e. the rotor 11 may extend forward beyond the hub profile 2 . In an embodiment, the inner wall extends within the central inner opening 6 of the hub profile 2 from the front end of the hub profile 2 (defined by the mean diameter Dm33) to near the front end of the rotor 11 of the motor 4.

[0025] The mean diameter Dm33 represents the inner diameter limit of the outer flow guiding surface 7 of the hub contour 2 which guides the main flow. Within this boundary, defined by the mean diameter Dm33, is the central inner opening 6 of the hub profile 2. The mean diameter Dm33 can usually be defined by the position of the hub contour 2 with its maximum axial extension towards the inflow side. The hub profile 2 has a sharp bend at the boundary defined by the mean diameter Dm33, but may be designed there to be more rounded.

[0026] Advantageously, the angle of the tangent of the outer flow guiding surface 7 of the hub contour 2, measured relative to the axis, as visible in cross section, decreases continuously from Dm33 in the main flow direction, such that the outer flow guiding surface 7 merges approximately tangentially into the outer contour of the hub ring 10. The effectiveness of the hub profile 2 is particularly evident if the outer flow guiding surface 7 which guides the main flow of the fan extends over a sufficiently large diametric range. Therefore, it is advantageous if the maximum outer diameter Da32-the average diameter Dm33 is 3% or more of the outer diameter DL34 of the impeller. In any case, it is advantageous for the maximum outer diameter Da32 to be greater than 110% of the average diameter Dm33.

[0027] The hub profile 2 is fixed in centre to the impeller 3 by means of a front fixing means 23 provided in the hub ring 10 . For example, it may be secured by gluing or clipping. The impeller 3 is fixed to the rotor 11 of the motor 4 by means of fixing means 15 arranged in the hub ring 10 . At the outer contour of the housing 13, the inlet nozzle 5, the cylindrical region 20 and the region of the radial expansion 21 are clearly visible in cross section. Advantageously, an impeller 3 having blades 9 with winglets 22 operates over a large portion of the cylindrical area 20 (at least 90% of the axial extension of the winglets 22) or over the entire area, as viewed in the axial direction. On the suction side of the guide vane 14, the release area 26 within the diameter expansion area 21 is clearly visible.

[0028] Figure 3 shows two characteristic curves of comparable axial fans at constant motor speed, plotted against the volume flow rate QV on the horizontal axis and the efficiency η on the vertical axis (in this example the static or total static system efficiency is shown). In one embodiment there is no hub profile (square symbols) with a flow guiding outer surface having a streamlined flow guiding shape on the inlet side. However, in another embodiment of otherwise identical construction, there is a hub contour having an outer flow guiding surface with a streamlined flow guiding shape (triangle symbols). It can be seen that using a hub profile with a flow guiding outer surface having a streamlined flow guiding shape improves the aerodynamic performance (higher maximum volume flow rate QV) and improves efficiency over a wide range of the characteristic curve. Here, in particular, the maximum static system efficiency is improved by about 2 percentage points, or relatively by about 6%. Typically, the use of hub profiles can improve static efficiency by approximately 0.1 to 10%.

[0029] In Fig. 4, similar to Fig. 3, two characteristic curves of comparable axial fans at constant motor speed are shown in a diagram with the volume flow rate QV on the horizontal axis and the suction side sound power level LW5(A) at A value on the vertical axis. In one embodiment, there is no hub profile with a flow guiding outer surface having a streamlined flow guiding shape on the inlet side (square symbol), while in the other embodiment of the otherwise identical structure, there is a hub profile with a flow guiding outer surface having a streamlined flow guiding shape (triangle symbol). It can be seen that the use of a hub contour having an outer flow guiding surface with a streamlined flow guiding shape reduces the sound power over a wide region of the characteristic curve, and in particular, the minimum sound level is reduced by about 0.7 dB. Typically, by using a hub contour, the minimum sound level can be reduced by approximately 0-3 dB. It has been found that the advantages in terms of noise generation resulting from the use of a hub contour having a flow-guiding outer surface with a streamlined flow-guiding shape are particularly evident when using guide wheels having guide vanes. Vortices that may be generated in the hub region due to the aerodynamically unfavorable design of the fan impeller inlet region can interact with the guide vanes mounted downstream of the impeller and generate loud noise. For this reason, in the case of fans with guide wheels, it is particularly advantageous to use a hub profile with an outer flow-guiding surface having a streamlined flow-guiding shape.

[0030] FIG. 5 shows a fan 1 in a perspective view obliquely from the inlet side and with an embodiment of an aerodynamically designed hub contour 2 which is open on the inlet side. In the embodiment, the hub profile 2 is integrated into a hub ring 10 of an impeller 3 which is fixed to a rotor 11 of a motor 4 by means of fixing means 15, advantageously screws. The blades 9 of the impeller 3 are also provided at their radially outer ends with features 22 (winglets), which in this embodiment have a different shape than in the embodiment according to FIGS. In particular, on the suction side of the vanes 9, a bevel is formed and on the radially outer side of the vanes 9, only a very thin web is present. Additionally, apart from the hub design, please also refer to the description of Figures 1 and 2. Those embodiments are similar in many respects to the embodiment shown here.

[0031] FIG. 6 is a cross-sectional view of the fan of FIG. 5 as viewed from the side, taken along a plane passing through the rotation axis of the impeller 3. As shown in FIG. Here too, the hub profile 2 is integrated with the hub ring 10 of the impeller 3 . Advantageously, the average diameter Da32 defining the outer boundary of the hub profile 2 or the transition of the impeller 3 to the hub ring 10 can be defined at the axial position of the flow-guiding outer surface 7 of the hub profile 2, i.e. at the position where the blades 9 of the hub ring 10 begin. The hub ring 10 itself is conical over the entire axial extension of the blades 9 of the impeller 3, i.e. its outer contour is not parallel to the axis. The fixing means 15 for fixing the impeller 3 to the rotor 11 of the motor 4 are integrated into the entire hub consisting of the hub ring 10 and the hub profile 2 . In an embodiment, the inner diameter Di31 is identical to the mean diameter Dm33 that defines the radially inner boundary of the outer flow-guiding surface 7 that guides the flow of the hub profile 2. No walls or the like of the hub profile 2 extend into the central inner opening 6 of the hub profile 2, which has a mean diameter Dm33.

[0032] FIG. 7 shows a fan 1 in an oblique perspective view from the inlet side with an embodiment of an aerodynamically designed hub contour 2 that is open on the inlet side. In contrast to the embodiment of FIG. 5, in the inner area of ​​the hub contour 2 a kind of grid structure 24 is designed. Due to the central inner opening 6 of the lattice structure 24, the hub contour 2 remains open and still ensures that the incoming conveying medium can flow over the rotor 11 of the motor 4 for the purpose of good motor cooling. Advantageously, the outer contour of the lattice structure 24 continues into the contour of the flow guiding outer surface 7, which is defined so as to extend tangentially and radially inwardly to the central inner opening 6 of the lattice structure 24. This embodiment has several advantages over the embodiment of FIG. On the one hand, the motor 4 is mechanically protected on the suction side and to a certain extent protected from coarse dirt. On the other hand, the additional shielding effect provided by the outer contour of the grid structure 24 can also have a beneficial effect on the main flow and therefore on the efficiency and low noise level of the fan 1 . Finally, it can also give the fan a more attractive appearance. The shape and arrangement of the central inner opening 6 and webs of the lattice structure 24 can be designed in a variety of ways, such as structured or unstructured, or a more rounded shaped central inner opening.

[0033] FIG. 8 shows a fan 1 in an oblique perspective view from the inlet side with an embodiment of an aerodynamically designed hub contour 2 that is open on the inlet side. In contrast to the embodiment of FIG. 5, in the inner region of the hub profile 2, radially inside the central inner opening 6 of the hub profile 2 or in the inner region allocated to the cooling of the motor 4, a plurality of active flow elements 25 are formed, which have an active and positive effect on the cooling flow around the rotor 11 of the motor 4. In particular, these flow elements 25 can cause stronger vortex formation, higher local flow velocities and / or greater air circulation in the inner region of the hub contour 2 or in the region of the rotor 11 of the motor 4 . For this purpose, a rotational movement of the impeller 3, its blades 9, the hub ring 10 and the hub contour 2 is effected. In this embodiment, the flow elements 25 resemble small curved stub wings. These are mounted inside the hub profile 2 , in a central inner opening 6 and are manufactured integrally with the impeller 3 . Since these flow elements 25 are not symmetrically formed with respect to the direction of rotation, their effect depends on the direction of rotation of the rotor 11 . However, this is generally not a limitation, since the direction of rotation of the impeller 3 is in any case predetermined by its geometric design.

[0034] FIG. 9 shows a fan 1 in an oblique perspective view from the inlet side with an embodiment of an aerodynamically designed hub profile 2 that is open on the inlet side, the hub profile 2 being designed as a separate part with an integrated fixing element 29. A rotor 11 of the motor 4 passes through a central inner opening 6 in the hub profile 2 and projects axially beyond this central inner opening 6 towards the inlet side. The slightly rounded front part of the rotor 11, the rotor bell, can advantageously interact with the flow-guiding outer surface 7 of the hub contour 2 for the main fan flow near the axis. In addition to the radially outer winglets 22 , the blades 9 of the impeller 3 also have intermediate winglets 27 which are designed as structures on the suction side of the blades 3 . Within the central inner opening 6 of the hub profile 2 a number of vanes 28 are integrated into the hub profile 2 . These vanes 28 have a certain degree of flexibility and fit tightly to the rotor 11 of the motor 4 even if the diameter of the rotor 11 varies. For configurations other than those described above, for example, the description of FIG. 1 can be referred to.

[0035] FIG. 10 is a cross-sectional view of the fan 1 of FIG. 9 as viewed from the side, taken along a plane passing through the rotation axis of the impeller 3. As shown in FIG. In FIG. 10b the area of ​​the hub profile 2 of the fan 1 of FIG. 10 is shown in enlarged detail. In FIG. 10 it can be seen that the hub ring 10 of the impeller 3 is essentially cylindrical. The fastening means 15 integrated into the hub ring 10 for fastening the impeller 3 to the rotor 11 of the motor 4 are essentially identical to the fastening means 29 integrated into the hub ring 10 on the inlet side for fastening the hub profile 2 to the impeller 3 or to the hub ring 10 of the impeller 3. This makes it possible to mount the impeller 3 on the rotor 11 of the motor 4 in the opposite direction to the conveying direction, for example making it possible to use the impeller 3 without guide wheels or guide vanes 14 .

[0036] The vanes 28, which are integrated into the hub profile 2, are in intimate contact with the rotor 11 of the motor 4 (FIG. 10b). As fastening means 29 of the hub profile 2 to the hub ring 10 of the impeller 3 a snap hook serves, engaging in a central inner opening 6 of the front fastening means 23 of the hub ring 10 of the impeller 3 . This allows the hub profile 2 to be simply attached to the impeller 3 by means of the hub ring 10 without the need for additional fastening elements or tools. The outer flow guide surface 7 of the hub ring 2 merges approximately tangentially into the outer surface of the hub ring 10 of the impeller 3 . In the area axially opposite the snap hooks which serve as fastening means 29 of the impeller 3 or of the hub profile 2 on the hub ring 10 of the impeller 3, recesses are formed in the outer flow-guiding surface 7 of the hub profile 2 (see also FIG. 9). The recess exists to allow the snap hook to be removed from the mold in a direction parallel to the axis using injection molding equipment.

[0037] In order to avoid repetition regarding further advantageous embodiments of the fan according to the invention, reference is made to the general part of the specification and to the appended claims.

[0038] Finally, the above-described embodiments of the fan according to the present invention serve only to illustrate the claimed teachings and are not intended to limit the claimed teachings to the embodiments. [Explanation of symbols]

[0039] 1. Fan 2. Hub contour on the inlet side 3. Fan impeller 4 Motor 5. Inlet nozzle 6 Central inner opening of hub contour 7. Flow guide outer surface of hub contour 8...not used 9. Impeller blades 10 Impeller hub ring 11 Motor rotor 12 Motor stator 13 Fan housing 14 Fan guide vanes 15 Fixing device for impeller to motor 16 Fixing device for fixing the fan to the inlet side of the system 17 Fixing device for the outlet side of the fan to the system 18 - Inlet side fixing device for grid to housing 19. Fixing device for outlet side of grid to housing 20 Cylindrical flow region in a housing 21 Integrated exhaust side diameter expansion section 22 Winglet / Outer Shape of Feather 23 - Forward fixing device integrated into impeller 24...Inlet side grid structure integrated into hub contour 25... Active cooling flow elements within the hub contour 26...Separation area of ​​housing diameter expansion area 27 Intermediate winglet 28 Plate 29. Fixing means between hub profile and hub ring 30...not used 31 Hub profile inner diameter Di 32 Hub profile outer diameter Da 33 Mean diameter of hub profile Dm 34 Impeller diameter DL

Claims

1. An axial, mixed flow or radial fan having an impeller driven by an outer rotor type electric motor, the impeller includes a hub ring that is rotationally fixedly connected to the rotor of an electric motor, preferably an external rotor motor, and that supports the blades; a hub profile is provided on the inflow side of the hub ring; An axial flow fan, a mixed flow fan, or a radial fan, wherein the hub profile includes a flow guiding outer surface that guides the flow, and a central inner opening that is adjacent to the flow guiding outer surface radially inward and has an inner surface facing the rotor.

2. 2. An axial, mixed flow or radial fan according to claim 1, characterized in that the hub profile is integral with the hub ring of the impeller in one piece.

3. 2. An axial, mixed or radial fan according to claim 1, characterized in that the impeller is attached to the rotor by a threaded connection via the integral hub profile.

4. 2. An axial, mixed flow or radial fan according to claim 1, characterized in that the hub profile is designed as a separate part and is plugged, clipped or otherwise fixed to the impeller in a form-fit, force-fit and / or material-fit manner.

5. 2. An axial, mixed flow or radial fan according to claim 1, characterized in that the hub profile is fixed to the hub ring by fastening means that are materially integrated with either the hub ring or the hub profile, preferably by snap hooks or clip fastenings.

6. 2. An axial, mixed flow or radial fan according to claim 1, wherein the hub profile can be fixed to the hub ring without the use of tools.

7. 2. An axial, mixed flow or radial fan according to claim 1, characterized in that the hub profile has active air guiding elements.

8. 2. An axial, mixed flow or radial fan according to claim 1, characterized in that the flow-guiding outer surface of the hub profile is free of steps, edges and creases.

9. 2. An axial, mixed flow or radial fan according to claim 1, wherein the flow-guiding outer surface of the hub profile merges substantially tangentially with the outer profile of the hub ring of the impeller.

10. 2. An axial, mixed flow or radial fan according to claim 1, characterized in that the flow-guiding outer surface of the hub profile has an acute or rounded transition, preferably a kind of bend, with the inner surface of the hub profile on the side of the central inner opening.

11. 2. An axial, mixed flow or radial fan according to claim 1, characterized in that the hub profile defines on its inner surface an inner diameter that substantially corresponds to the outer diameter of the front part of the rotor, in particular the rotor bell.

12. 2. An axial, mixed flow or radial fan according to claim 1, wherein the rotor extends within the hub profile and beyond the hub profile forward, i.e., towards the inlet side.

13. 2. An axial, mixed flow or radial fan according to claim 1, characterized in that the position of the hub profile relative to the hub ring and / or the rotor is adjustable by adjustment and locking means.

14. 2. An axial, mixed flow or radial fan according to claim 1, characterized in that a plurality of flow elements having small short blades acting as guides are provided on or within the inner surface of the hub profile.

15. 15. An axial, mixed flow or radial fan according to claim 14, characterized in that the flow elements protrude at least slightly from the inner surface and / or are curved.

16. In the case of a rotor that protrudes beyond the hub profile toward the inlet side, a plurality of resilient vanes are provided within the hub profile, preferably on the inner surface of the hub profile; 2. An axial flow fan, mixed flow fan or radial fan according to claim 1, wherein the elastic blades are in close contact with the surface of the rotor even when rotors of slightly different diameters are used.

17. 2. An axial, mixed flow or radial fan according to claim 1, characterized in that the central inner opening of the hub profile has a structure that influences the flow, preferably a regular or irregular, symmetrical or asymmetrical lattice structure, optionally curved around the rotor bell.

18. 18. An axial, mixed flow or radial fan according to claim 17, characterized in that the structure or lattice structure extends to the flow-guiding outer surface of the hub profile.

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