Axial fan wheel and axial fan

Abstract

The invention relates to an axial fan wheel (7) for an axial fan (5) of a vehicle cooling system (1), comprising a hub (9), a ring (10) which runs concentrically around the hub (9), and several blades (11) which connect the ring (10) to the hub (9). Noise reduction on the axial fan (5) equipped with the axial fan wheel (7) can be achieved by the ring (10) having several radially projecting elevations (13) on one of the inner sides (12) of the ring facing the hub (9), each of which is arranged between two blades (11).

Description

[0001] The present invention relates to an axial fan wheel for an axial fan of a vehicle cooling system according to the preamble of claim 1. The invention also relates to an axial fan equipped with such an axial fan wheel.

[0002] From DE 698 20 853 T2, an axial fan with a generic axial fan wheel is known. The axial fan wheel has a hub, a ring rotating concentrically around the hub, and several blades connecting the ring to the hub.

[0003] For motor vehicles, especially passenger cars, considerable effort is made to offer the highest possible level of comfort for their users. Of particular interest is the reduction of disturbing noise. A significant noise source is the axial fan, which, in a vehicle's cooling system, drives and / or assists the airflow through the radiator. The axial fan can be positioned upstream of the radiator in a pushing or pushing direction, or downstream in a pulling or suction direction. Noise from the axial fan during operation is primarily due to turbulence that can develop as air flows through the rotating fan wheel.

[0004] The present invention addresses the problem of providing an improved or at least a different embodiment for an axial fan wheel of the type described above or for an axial fan equipped with such a wheel, which is characterized in particular by reduced noise generation during the operation of the axial fan.

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

[0006] The invention is based on the general concept of providing raised areas on the ring between the blades that impede flow along the ring's surface. By impeding flow along the ring's surface, disruptive turbulence can be reduced. Accordingly, these raised areas on the ring can reduce the noise generated by the axial fan.

[0007] Specifically, it is proposed that the ring has several radially projecting or protruding ridges on one of its inner surfaces facing the hub. These ridges are arranged between two blades in a circumferential direction around the axis of rotation of the axial fan wheel. In other words, the ridges are distributed along the inner surface of the ring in such a way that each ridge is located between two adjacent blades. The surface at which the flow is disturbed by the ridges is formed by the inner surface of the ring.

[0008] According to an advantageous embodiment, the raised sections can be integrally formed on the ring. The axial fan wheel is, in particular, a one-piece injection-molded plastic part in which the hub, the blades, and the ring with the raised sections are formed. Thus, the injection-molded axial fan wheel, when it emerges from the injection mold, already has the hub, the blades, and the ring with the raised sections.

[0009] According to an advantageous embodiment, at least one of the projections is arranged on the inner surface of the ring between each pair of blades in the circumferential direction. This ensures that at least one projection is formed on the inner surface of the ring in every gap between two adjacent blades in the circumferential direction of the axial fan wheel.

[0010] In another embodiment, at least two of the projections are arranged on the inner surface of the ring between each pair of adjacent blades in the circumferential direction. With two or more projections, their influence on the flow can be positioned more effectively than with a single projection.

[0011] According to another embodiment, the at least two projections arranged circumferentially between each pair of blades can be arranged side by side circumferentially, i.e., separately from each other. The separate arrangement of several projections improves the adaptation to the flow on the inner surface of the ring, thereby optimizing the reduction of disruptive turbulence.

[0012] A particularly advantageous embodiment is one in which the protrusions transition seamlessly into the inner surface of the ring both axially and circumferentially. This avoids edges at these transitions that could cause additional turbulence and noise. Additionally or alternatively, the protrusions can be expediently rounded or configured so that they themselves have no edges or points. Such points and / or edges can be the cause of disruptive turbulence.

[0013] In the present context, a “configuration” is synonymous with a “design” and / or “setup”, so that the phrase “configured so that” is synonymous with the phrase “designed so that” and / or “set up so that”.

[0014] In principle, the elevations can be point-like, e.g., as hillocks rising from the inner surface of the ring. They can also be linear, e.g., as ribs. According to an advantageous embodiment, the elevations can be designed as elongated ribs. These ribs also provide a flow-guiding effect, which improves the avoidance or reduction of disruptive turbulence. The elongated ribs are significantly larger in their longitudinal direction than transversely. For example, the ribs can have a height of 1 mm to 5 mm transversely to their longitudinal and radial directions. Furthermore, the ribs can have a width of between 1.5 mm and 6 mm transversely to their longitudinal and radial directions.In their longitudinal direction, the ribs can have a rib length that is at least ten times greater than the rib height and / or the rib width. The rib length depends in particular on the number of ribs arranged between two circumferentially adjacent blades on the inner surface of the ring.

[0015] According to an advantageous embodiment, the ribs may be straight. In another embodiment, the ribs may also be bent or curved. Furthermore, an embodiment is also conceivable in which each rib has at least one curved section and at least one straight section.

[0016] According to another advantageous embodiment, the ribs can be inclined at a rib angle relative to the circumferential direction. In other words, the ribs do not extend parallel to the circumferential direction. According to one advantageous embodiment, the rib angle is a maximum of 45°. Preferably, the rib angle lies within a range of 20° to 40°.

[0017] In another embodiment, the blades on the ring can be angled relative to the axial direction of the axial fan wheel, with the ribs being angled in the same orientation as the blades relative to the axial direction. This allows for advantageous flow guidance by the ribs, which contributes to reducing turbulence and noise.

[0018] According to another embodiment, the blades on the ring can be set at an angle of attack relative to the axial direction of the axial fan wheel, with the ribs being set at the same angle of attack as the blades relative to the axial direction. By selecting the same angle of attack for both the blades and the ribs, the reduction of turbulence can be further optimized. It should be noted that the blades can have a varying angle of attack along their radial extent. The angle of attack of the blades directly at the ring or on the inner surface of the ring is relevant for comparison with the angle of attack of the ribs.

[0019] According to another embodiment, the protrusions on the inner surface of the ring can be spaced apart from the blades in the circumferential direction. This reduces any disruptive interaction between the blades and the protrusions with regard to the flow around the blades.

[0020] According to an advantageous embodiment, the projections on the inner surface of the ring can be spaced circumferentially from the adjacent blades such that the projections and the blades do not overlap. In other words, each projection on the inner surface of the ring is spaced circumferentially from the leading and trailing edges of the adjacent blades. Avoiding circumferential overlap reduces disruptive interactions of the projections with the airflow around the fins and thereby improves the desired effect of the projections in reducing turbulence and noise.

[0021] According to another embodiment, at least two projections, arranged between two circumferentially adjacent blades, are positioned side by side on the inner surface of the ring and spaced apart from each other circumferentially. Consequently, the ends of the two projections facing each other circumferentially are spaced apart. This measure also prevents disruptive interactions between separate projections located between two adjacent blades, thus improving the projections' effectiveness in reducing disruptive turbulence.

[0022] In another embodiment, the ring may have a circumferentially circumferential, radially outwardly projecting collar on an upstream side. This collar prevents disruptive backflow within the axial fan from the pressure side or downstream side along an outer ring surface radially away from the inner ring surface onto the suction side or upstream side of the axial fan wheel.

[0023] In another embodiment, the blades can be arranged asymmetrically in the circumferential direction. In other words, the blades can have different distances from each other in the circumferential direction. It has been shown that such an asymmetrical arrangement of the blades has a positive effect on reducing noise generation in the rotating axial fan wheel.

[0024] An axial fan according to the invention, configured for a vehicle cooling system, has a fan frame for attaching the axial fan to a cooling duct of the vehicle cooling system and an axial fan wheel of the type described above, which is rotatably arranged on the fan frame about the axis of rotation.

[0025] According to an advantageous embodiment, the axial fan can include an electric motor for driving the axial fan wheel, which is rigidly connected to the hub on one side and to the fan housing on the other. With the aid of such an electric motor, the axial fan can be switched on as needed to generate or assist the airflow through the respective radiator of the vehicle's cooling system. During vehicle operation, the airflow from driving can already generate a certain amount of airflow, which can then be augmented as needed by activating the axial fan. The electric motor can, in particular, be configured as a hub motor and housed in the hub of the axial fan wheel.

[0026] The axial fan is preferably configured as a pull axial fan, which is arranged downstream of a radiator in the vehicle cooling system. This radiator is to be subjected to the airflow generated or amplified by the axial fan. An embodiment is also possible in which the axial fan is configured as a push fan, i.e., arranged upstream of the other fan. Furthermore, an embodiment of a vehicle cooling system is conceivable which has at least two radiators through which the airflow passes, wherein the axial fan can be arranged upstream or downstream of both radiators, or even between the two radiators.

[0027] Further important features and advantages of the invention will become apparent from the dependent claims, the drawings and the associated description of the figures based on the drawings.

[0028] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention as defined by the claims. Components of a higher-level unit, such as a device, apparatus, or arrangement, mentioned above and those to be mentioned below, which are designated separately, can form separate parts or components of this unit or be integral areas or sections of this unit, even if this is depicted differently in the drawings.

[0029] Preferred embodiments of the invention are shown in the drawings and are explained in more detail in the following description, wherein identical reference numerals refer to identical or similar or functionally identical components.

[0030] They show, schematically, Fig. 1 A highly simplified sectional view of a vehicle cooling system in the area of ​​an axial fan wheel, Fig. 2 an isometric view of a section of an axial fan wheel of the axial fan, Fig. 3 an isometric view of a section of the axial fan wheel, but in a different embodiment, Fig. 4 another isometric view of a section of the axial fan wheel.

[0031] Accordingly Fig. 1 comprises a vehicle cooling system 1 (only partially shown here) and a cooling duct 2 for guiding an airflow 3, which is in Fig. 1 is indicated by an arrow. The vehicle cooling system 1 is also equipped with at least one radiator 4, through which the airflow 3 can flow and through which a coolant circulates in a cooling circuit of the vehicle cooling system 1 (not shown), into which the radiator 4 is integrated. The airflow 3 can be generated in part by the wind generated while a vehicle equipped with the vehicle cooling system 1 is in motion. In order to be able to generate the airflow 3 even when the vehicle is stationary, or to increase the airflow 3 if necessary, the vehicle cooling system 1 has an axial fan 5, which in the example of the Fig. The axial fan 5 is arranged downstream of the cooler 4, so that it is configured here as a pulling axial fan 5. The axial fan 5 has a fan shroud 6 and an axial fan wheel 7. The fan shroud 6 is configured for attaching the axial fan 5 to the cooling channel 2. The axial fan wheel 7 is rotatably mounted on the fan shroud 6 about a rotational axis R. The axial fan 5 can be equipped with an electric motor 8 for rotating the axial fan wheel 7.

[0032] The axis of rotation R of the axial fan wheel 7 defines an axial direction of the axial fan wheel 7, which runs parallel to the axis of rotation R. Furthermore, the axis of rotation R defines a radial direction of the axial fan wheel 7, which arises perpendicular to the axis of rotation R. In addition, the axis of rotation R defines a circumferential direction U of the axial fan wheel 7, which rotates around the axis of rotation R and which is in the Fig. 1, Fig. 2, Fig. 3 to Fig. 4 is indicated by a double arrow.

[0033] According to the Fig. 1, Fig. 2, Fig. 3 to Fig. Figure 4 shows that the axial fan wheel 7 has a hub 9, a ring 10 and several blades 11. The hub 9, which is located in the Fig. 2, Fig. 3 to Fig. 4, which is only partially visible, is arranged concentrically to the axis of rotation R. The ring 10 rotates concentrically around the hub 9. The blades 11 connect the ring 10 radially to the hub 9. The electric motor 8 can, in particular, be configured as a hub motor and installed in the hub 9 of the axial fan wheel 7.

[0034] According to the Fig. 2, Fig. 3 to Fig. 4 The ring 10 has several radially projecting protrusions 13 on an inner ring side 12, which faces radially towards the hub 9. The protrusions 13 are each arranged in the circumferential direction U between two blades 11 that are adjacent in the circumferential direction U. In the example of the Fig. 2. The number and distribution of the protrusions 13 are chosen such that, in the circumferential direction U, exactly one such protrusion 13 is arranged on the inner side 12 of the ring between each pair of blades 11 that are adjacent in the circumferential direction U. In the case of the Fig. 3 and Fig. In the embodiments shown in Figure 4, the number and distribution of the projections 13 are selected such that, in the circumferential direction U, exactly two such projections 13 are arranged on the inner surface 12 of the ring between each pair of blades 11 that are adjacent in the circumferential direction U. In other embodiments, three or more such projections 13 can also be arranged on the inner surface 12 of the ring between each pair of blades 11 that are adjacent in the circumferential direction U. Preferably, however, a maximum of four projections 13 are arranged on the inner surface 12 of the ring between each pair of blades 11 that are adjacent in the circumferential direction U.

[0035] Provided according to the Fig. 3 and Fig. 4 where several protrusions 13 are arranged in the circumferential direction U between each pair of blades 11 on the inner side 12 of the ring, these protrusions 13 are designed separately, i.e. next to each other in the circumferential direction U and arranged so that they do not touch each other.

[0036] According to the Fig. 2, Fig. 3 to Fig. 4. The projections 13 are geometrically shaped such that they transition seamlessly into the inner surface 12 of the ring, both axially and circumferentially U. Furthermore, the projections 13 are rounded, so that they themselves have no edge or point. In the embodiments shown here, the projections 13 are also designed as linear ribs 14. The ribs 14 are elongated and therefore narrow. Furthermore, the ribs 14 are configured as straight lines. The projections 13 or the ribs 14 can be configured to extend over at least 50% of a distance 15 measured in the circumferential direction U between two blades 11 that are immediately adjacent in the circumferential direction U on the ring 10 or on the inner surface 12 of the ring. This distance 15 is in Fig. 2 representing the Fig. 2, Fig. 3 to Fig. 4 entered. Accordingly, between each pair of adjacent blades 11 in the circumferential direction U, the individual elevations 13 or ribs 14 extend in the Fig. In the embodiment shown in Figure 1, the circumferential direction U extends over a larger area than the two protrusions 13 and ribs 14 in the examples of Figure 1. Fig. 3 and Fig. 4.

[0037] According to Fig. 4. The ribs 14 can be angled at a rib angle 16 relative to the circumferential direction U. This rib angle 16 is, in the example of the Fig. 4 approximately 30°. Preferably, this rib angle 16 can be a maximum of 45°. Furthermore, the blades 11 are according to Fig. 4 on ring 10 or on the inner side of ring 12 relative to the axial direction at an angle of attack 17, which can also be referred to as the blade angle of attack 17. The blade angle of attack 17 can, for example, be approximately 60°. Furthermore, according to Fig. 4. The ribs 14 are also set at an angle of attack 18 relative to the axial direction, which can hereinafter also be referred to as the rib angle of attack 18. It is advantageous that the ribs 14 are set at the same orientation relative to the axial direction as the blades 11. In the Fig. 2, Fig. 3 to Fig. 4 is a suction side or inlet side 19 of the axial fan wheel 7 facing the viewer, while a pressure side or outlet side 20 faces away from the viewer. Accordingly, the inlet side 19 is located in Fig. The downstream side 20 is located on the left side of the axial fan wheel 7, while the downstream side 20 is located on the right side of the axial fan wheel 7. With respect to the flow direction through the axial fan wheel 11, which is oriented from the upstream side 19 to the downstream side 20, the blades 11 on the ring 10 and on the inner ring 12 are angled to the right, i.e., clockwise, relative to the axial direction. Accordingly, the ribs 14 are also angled to the right, i.e., clockwise, relative to the flow direction. In the embodiment shown here, the blade angle 17 is also equal to the rib angle 18. In other words, the ribs 14 are angled with the same angle 17, 18 as the blades 11 relative to the axial direction. The rib angle 16, the blade angle 17, and the rib angle 18 are representative of the Fig. 2, Fig. 3 to Fig. 4 only in Fig. 4 entered.

[0038] In the embodiments shown here, the Fig. 2, Fig. 3 to Fig. In Figure 4, the projections 13 on the inner surface of the ring 12 are spaced circumferentially U from the blades 11. This spacing from the blades 11 is chosen such that the projections 13 and the blades 11 do not overlap each other circumferentially U. The blades 11 each have a leading edge 21 on the upstream side 19 and a trailing edge 22 on the downstream side 20. In the examples shown here, the projections 13 on the inner surface of the ring 12 are spaced circumferentially U from both the leading edges 21 and the trailing edges 22 of the blades 11 adjacent in the circumferential direction U. In other words, on the inner side of the ring 12 there are circumferential sections in which neither one of the blades 11 nor one of the elevations 13 is arranged, which extend in the circumferential direction U between one of the blades 11 and the nearest elevation 13.

[0039] Furthermore, the embodiments of the Fig. 3 and Fig. 4, in which at least two projections 13 are provided between two adjacent blades 11 on the inner surface 12 of the ring, the dimensions and arrangement of the projections 13 are selected such that the at least two projections 13 on the inner surface 12 of the ring are arranged side by side in the circumferential direction U and spaced apart from each other in the circumferential direction U. The spacing is selected such that the ends of the projections 13 facing each other in the circumferential direction U are spaced apart from each other in the circumferential direction U. In other words, in these embodiments, the inner surface 12 of the ring has a circumferential section in which neither one of the projections 13 nor one of the blades 11 extends and which is arranged in the circumferential direction U between two adjacent projections 13.

[0040] During the Fig. 2, Fig. 3 to Fig. In the embodiments shown in Figure 4, the ring 10 has a collar 23 on the upstream side 19, which extends circumferentially U and projects radially outwards. The collar 23 serves to prevent or at least reduce unwanted backflow along the outer surface of the ring, radially away from the hub 9, from the downstream side 20 or pressure side back to the upstream side 19 or suction side. In the installed state, the collar 23 overlaps according to the Fig. 4 a ring contour 24 of the fan frame 6. Reference symbol list 1 vehicle cooling system 2 Cooling channel 3 Airflow 4 coolers 5 axial fans 6 fan shroud 7 Axial fan wheel 8 Electric motor 9 hub 10 rings 11 shovel 12 Ring inside 13 Survey 14th rib 15 distance 16 rib angles 17 Blade angles 18 rib angles 19 Upstream side 20 Outflow side 21 Leading edge 22 Egress edge 23 collars 24 ring contour R axis of rotation U circumferential direction QUOTES INCLUDED IN THE DESCRIPTION

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

[0000] DE 698 20 853 T2

[0002]

Claims

Axial fan wheel (7) for an axial fan (5) of a vehicle cooling system (1),- with a hub (9),- with a ring (10) which runs concentrically around the hub (9),- with several blades (11) which connect the ring (10) to the hub (9), characterized in that the ring (10) has several radially projecting elevations (13) on an inner surface (12) facing the hub (9), each of which is arranged between two blades (11). Axial fan wheel (7) according to claim 1, characterized in that at least one of the projections (13) is arranged on the inner side (12) of the ring between each pair of blades (11). Axial fan wheel (7) according to one of the preceding claims, characterized in that at least two of the projections (13) are arranged between each pair of blades (11) on the inner side (12) of the ring. Axial fan wheel (7) according to one of the preceding claims, characterized in that the at least two projections (13) which are arranged between each of two blades (11) are arranged next to each other in the circumferential direction (U). Axial fan wheel (7) according to one of the preceding claims, characterized in that the projections (13) transition continuously into the inner surface of the ring (12), and / or that the projections (13) are rounded. Axial fan wheel (7) according to one of the preceding claims, characterized in that the projections (13) are each designed as an elongated rib (14). Axial fan wheel (7) according to claim 6, characterized in that the ribs (14) are designed straight. Axial fan wheel (7) according to claim 6 or 7, characterized in that the ribs (14) are set at a rib angle (16) relative to the circumferential direction (U). Axial fan wheel (7) according to one of claims 6 to 8, characterized in that the blades (11) on the ring (10) are angled relative to the axial direction, and that the ribs (14) are angled with the same orientation as the blades (11) relative to the axial direction. Axial fan wheel (7) according to one of claims 6 to 9, characterized in that the blades (11) on the ring (10) are set at a blade angle (17) relative to the axial direction, and that the ribs (14) are set at a rib angle (18) relative to the axial direction which is equal to the blade angle (17). Axial fan wheel (7) according to one of the preceding claims, characterized in that the projections (13) on the inner side of the ring (12) are spaced apart in the circumferential direction (U) from the blades (11). Axial fan wheel (7) according to claim 11, characterized in that the projections (13) on the inner side of the ring (12) are spaced apart in the circumferential direction (U) from the blades (11) adjacent to it in the circumferential direction (U) to such an extent that the projections (13) and the blades (11) do not overlap in the circumferential direction (U), and / or that the respective projection (13) on the inner side of the ring (12) is spaced apart in the circumferential direction (U) from the leading edges (21) and trailing edges (22) of the blades (11) adjacent in the circumferential direction (U). Axial fan wheel (7) according to one of the preceding claims, characterized in that at least two projections (13) which are arranged between two blades (11) adjacent in the circumferential direction (U) are arranged next to each other on the inner side (12) of the ring in the circumferential direction (U) and are spaced apart from each other in the circumferential direction (U). Axial fan wheel (7) according to one of the preceding claims, characterized in that the ring (10) has a collar (23) extending radially outwards on an upstream side (19) in the circumferential direction (U). Axial fan (5) for a vehicle cooling system (1),- with a fan frame (6) for attaching the axial fan (5) to a cooling duct (2) of the vehicle cooling system (1),- with an axial fan wheel (7) according to one of the preceding claims, which is rotatably arranged on the fan frame (6) about an axis of rotation (R).

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