fan

Abstract

The present invention relates to a fan (1) with a fan wheel (2) with fan blades (3) and a cover ring (4) surrounding the edge of the fan wheel (2). The essential element of the invention is that - that the fan wheel (2) has a mantle ring (6) surrounding the fan blades (3) at their outer end, - that the mantle ring (6) has an outer circumferential side (11), - that the cover ring (4) has an inner circumferential side (13), - that the outer circumferential side (11) is arranged opposite the inner circumferential side (13), - that a protrusion (14) directed towards the outer circumferential side (11) of the mantle ring (6) is arranged on the inner circumferential side (13) of the cover ring (4). This allows for the creation of an efficient and quiet fan (1).

Description

[0001] The present invention relates to a fan with a fan wheel having fan blades and a cover ring surrounding the edge of the fan wheel, according to the preamble of claim 1. The invention also relates to an air conditioning device for a motor vehicle with such a fan.

[0002] Fans are used in a variety of applications in motor vehicles, for example, for air conditioning a passenger compartment or for cooling an engine. To improve rigidity and thus also improve performance, as well as to reduce noise emissions, fan wheels are used whose fan blades are enclosed at their outer ends by a casing ring, often also called a fan ring. The outer ends of the individual fan blades of the fan wheel are firmly connected to this casing ring. A frame with a cover ring surrounds the fan wheel, and this frame can also support a motor that drives the fan wheel.

[0003] A disadvantage of fans known from the prior art is that air vortices can form between the outer ring of the fan wheel and a cover ring due to backflow, which not only reduce the efficiency of the fan but also lead to increased noise emissions.

[0004] The present invention therefore deals with the problem of providing an improved or at least an alternative embodiment for a fan of the generic type, by means of which in particular the disadvantages known from the prior art can be overcome.

[0005] This problem is solved 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 concept of designing a geometry between the outer surface of the fan wheel and the inner surface of a cover ring of a fan such that the turbulence caused by backflow during operation of the fan wheel is at least reduced, preferably even avoided, thereby not only increasing the efficiency of the fan but also, in particular, reducing noise emissions. The fan according to the invention has a fan wheel with fan blades that are enclosed or fixed at their outer end by means of a casing ring. Furthermore, the fan has a frame with a cover ring that surrounds the fan wheel at its edge.According to the invention, the casing ring has an outer circumferential side and the cover ring an inner circumferential side, wherein the outer circumferential side is arranged opposite the inner circumferential side and wherein a protrusion directed towards the outer circumferential side of the casing ring is arranged on the inner circumferential side of the cover ring. This protrusion makes it possible to at least reduce, and preferably even to prevent, the turbulence that previously occurred in this area and thus also the noise emission generated in this area, caused by backflow between the casing ring and the cover ring. With the fan according to the invention, a fan can therefore be created that is not only more efficient but also improved with regard to noise emission.

[0007] In an advantageous embodiment of the solution according to the invention, an outwardly projecting annular collar extends from the mantle ring on an upstream side, wherein the mantle ring and the annular collar define a corner region with a first end face and the outer circumferential side. The cover ring has a contour substantially complementary to this corner region of the fan wheel, with a second end face and the inner circumferential side, wherein the first end face is opposite the second end face and the outer circumferential side is opposite the inner circumferential side. The protrusion directed towards the outer circumferential side of the mantle ring is located on the inner circumferential side of the cover ring. The corner region formed by the end faces and the circumferential surfaces can create a type of labyrinth seal, which at least reduces any backflow occurring there during fan operation.

[0008] In an advantageous embodiment of the fan according to the invention, the inner circumferential side of the cover ring has an axial length ZW. The axial length ZW can, for example, be between 14 and 18 mm. This allows for a comparatively long axial sealing gap between the outer ring of the fan wheel and the cover ring. Additionally or alternatively, a radial distance GH between the inner circumferential side of the cover ring and the outer circumferential side of the outer ring can be, for example, approximately 6 mm. Such a selected radial distance GH enables, on the one hand, contactless rotation of the fan wheel in the cover ring in all operating conditions and, on the other hand, a comparatively thin gap, which at least reduces undesirable backflow.

[0009] In a particularly preferred embodiment of the fan according to the invention, an axial length RZ2 of the protrusion fulfills the following condition: 0.15*ZW <RZ2<0,4*ZW. The axial length RZ2 of the raised section, which is greater than the axial length ZW of the inner circumferential side of the cover ring, further reduces the radial distance GH between the inner circumferential side of the cover ring and the outer circumferential side of the mantle ring in this area, forcing the backflow to flow around the raised section. This forced flow around the raised section reliably prevents the turbulence that previously occurred in this area. As the backflow continues, it can again utilize the entire radial distance GH between the inner circumferential side of the cover ring and the outer circumferential side of the mantle ring without generating turbulence. The axial length RZ2 of the raised section is only a fraction of the axial length ZW of the inner circumferential side of the cover ring.

[0010] In a further advantageous embodiment of the fan according to the invention, a radial height RZ3 of the protrusion fulfills the following condition: 0.05*GH <RZ3<0,4*GH.

[0011] Specifically, this means that the radial height RZ3 is between 5 and 40% of the radial distance GH between the inner circumference of the cover ring and the outer circumference of the mantle ring. Due to the comparatively low radial height RZ3, backflow for pressure equalization remains possible. However, by forcing the backflow around the raised section, the turbulence previously occurring in this area and the resulting noise emissions, which are perceived as disruptive, can at least be reduced, and preferably even eliminated.

[0012] In a further advantageous embodiment of the fan according to the invention, a distance RZ1 of the protrusion from a downstream edge of the inner circumferential side of the cover ring fulfills the following condition: 0.03*ZW <RZ1<0,3*ZW.

[0013] Specifically, this means that the raised section on the cover ring is positioned near the upstream edge of the cover ring, precisely where turbulence occurred in previous fan impellers. By positioning the raised section in this exact area, airflow is forced around it, thereby reducing noise emissions and increasing fan efficiency. "Upstream" here refers to the direction of the backflow.

[0014] In a further advantageous embodiment of the fan according to the invention, the raised section is formed integrally with the cover ring, in particular as a one-piece injection-molded plastic part. Providing such a raised section can thus be achieved with minimal additional effort by a single modification of the plastic injection mold. It is understood, of course, that the raised section is preferably arranged completely around the cover ring. By forming the raised section integrally with the cover ring, both the cover ring and the raised section can be manufactured simply, with high precision, and also cost-effectively. Alternatively, it is also theoretically conceivable that such a raised section could first be formed separately in a ring-like manner and then joined to the cover ring, for example, by bonding.This allows for a greater variety of options, as different surveys can be planned and an exactly suitable survey can be selected for each individual case.

[0015] In a further advantageous embodiment of the fan according to the invention, an upstream end face and an downstream end face of the projection are inclined to the inner circumferential surface. This reduces the impact flow, as the inclined upstream end face serves as a guide element to direct the backflow around the projection. "Upstream and downstream" here refers to the direction of the backflow, which runs opposite to the main flow.

[0016] In a further advantageous embodiment of the fan according to the invention, the inner circumferential surface of the cover ring runs parallel to the outer circumferential surface of the casing ring. This creates a substantially parallel gap between the outer and inner circumferential surfaces. Additionally or alternatively, the first end face of the ring collar can also run parallel to the second end face of the cover ring. This creates a substantially right-angled channel between the cover ring and the fan wheel, which acts as a kind of labyrinth seal and thereby at least reduces unwanted backflow.

[0017] The present invention is further based on the general idea of ​​equipping an air conditioning system for a motor vehicle with a fan described in the preceding paragraphs, thereby transferring the advantages described with respect to the fan to the air conditioning system. Specifically, these advantages lie in particular in increased performance, increased efficiency of the fan, and lower noise emissions during operation, which is especially advantageous when using the fan according to the invention in an air conditioning system according to the invention for an electric vehicle, which is considered particularly sensitive to noise.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] They show, schematically, Fig. 1 a sectional view through a fan according to the invention, Fig. 2 a representation as in Fig. 1, however, with a simulated flow during operation of the fan.

[0022] According to the Fig. 1 and Fig. Figure 2 of the invention comprises a fan 1 with a fan wheel 2 with fan blades 3 and a cover ring 4 surrounding the edge of the fan wheel 2. The cover ring 4 is part of a frame 5. The fan wheel 2 also has a mantle ring 6 enclosing the fan blades 3 at their outer end, from which an outwardly projecting annular collar 8 projects on an upstream side 7. The mantle ring 6 and the annular collar 8 define a corner region 9 with a first end face 10 and an outer circumferential side 11. The upstream side 7 relates to a direction of a main flow 18. The cover ring 4 has a contour substantially complementary to this corner region with a second end face 12 and an inner circumferential side 13. The first end face 10 is arranged opposite the second end face 12, while the outer circumferential side 11 is arranged opposite the inner circumferential side 13.On the inner circumferential side 13 of the cover ring 4, a protrusion 14 is arranged, directed towards the outer circumferential side 11 of the mantle ring 6. Previously, without this protrusion 14, vortices formed in the area of ​​this protrusion 14, which not only led to a reduction in the performance or efficiency of the fan 1 according to the invention, but also to a disturbing noise generation. With the protrusion 14 provided according to the invention, vortices can be avoided in this area, which is reflected in the flow 15 accordingly. Fig. 2 is clearly visible.

[0023] The projection 14 can be formed integrally with the cover ring 4, in particular as a one-piece injection-molded plastic part, which makes the production of the projection 4 not only cost-effective but also technically simple. Alternatively, it is of course also conceivable that the projection 14 is formed in a ring-like manner and manufactured separately, and only then joined to the also separately manufactured cover ring 4, in particular by bonding.

[0024] If one considers survey 14 according to the Fig. 1 and Fig. A closer look at Figure 2 reveals that it has an upstream end face 16 and an outstream end face 17, both of which are inclined to the inner circumferential surface 13. This inclined design, particularly of the upstream end face 16, allows for a low-noise and flow-optimized deflection of the backflow 15 around the protrusion 14. The backflow 15 flows in the opposite direction to the main flow 18, which is generated by the rotation of the fan wheel 2.

[0025] If one considers the Fig. 1 and Fig. 2. Further, it can be seen that the inner circumferential side 13 runs parallel to the outer circumferential side 11, thus creating a channel with nearly parallel walls between the cover ring 4 and the mantle ring 6 of the fan wheel 2. The first end face 10 and the second end face 12 can also run parallel to each other, causing the backflow 15 to be deflected at the corner area 9, thereby creating a kind of labyrinth seal.

[0026] The inner circumferential side 13 of the cover ring 4 has an axial length ZW, where the axiality of the fan 1 refers to its axis of rotation, which is located in the Fig. 1 and Fig. 2 runs from left to right in the image plane. For example, the radial distance GH between the inner circumferential side 13 of the cover ring 4 and the outer circumferential side 11 of the mantle ring 6 is approximately 6 mm.

[0027] In the fan 1 according to the invention, an axial length RZ2 of the elevation 14 fulfills the following condition: 0.15*ZW <RZ2<0,4*ZW.

[0028] The axial length RZ2 is measured at the base of the elevation 14, so that it is shorter at its free end projecting towards the outer shell surface 11 due to the sloping upstream and downstream end faces 16 and 17.

[0029] A radial height RZ3 of the elevation 14 fulfills the following condition in the fan 1 according to the invention: 0.05*GH <RZ3<0,40*GH

[0030] Specifically, this means that the radial height RZ3 of the protrusion 14 is approximately 5–40% of the distance GH between the inner circumferential surface 13 of the cover ring 4 and the outer circumferential surface 11 of the mantle ring 6. Even this small radial height RZ3 is sufficient to avoid or at least reduce the turbulence that would occur in this area without such a protrusion 14 and which would at least increase noise emissions or reduce performance.

[0031] If one considers the Fig. 1 further, it can be seen that a distance RZ1 of the elevation 14 from a downstream edge 19 of the inner circumferential side 13 of the cover ring 4 fulfills the following condition: 0.03*ZW <RZ1<0,3*ZW.

[0032] Specifically, this means that the distance of the protrusion 14 from the upstream edge 19 of the inner circumferential side 13 is between 3 and 30% of the axial length ZW of the inner circumferential surface 13 and thus corresponds to the Fig. 1 and Fig. 2 shifted to the right, i.e. arranged off-center on the inner circumferential surface 13.

[0033] The fan 1 can be part of an air conditioning unit 20 for a motor vehicle 21.

[0034] All in all, the fan 1 and the air conditioning unit 20 according to the invention enable significantly quieter operation of the fan 1, since, due to the raised area 14 on the inner circumferential surface 13 of the cover ring 4 provided according to the invention, flow vortices that previously occurred in this area can be avoided, or at least reduced, for the first time. At the same time, this increases the efficiency of the fan 1 according to the invention and thus indirectly also of the air conditioning unit 2. In particular, in a motor vehicle 21 designed as an electric vehicle, this can reduce energy consumption and, for example, increase the driving range. Reference symbol list 1 fan wheel 2 fans 3 fan blades 4 Cover ring 5 frame 6 mantle ring 7. Upstream side 8 Ring collar 9 Corner area 10 First front 11 External perimeter area 12 Second front 13 Inner perimeter area 14 Survey 15 Current 16 Upstream front face 17 Downstream end face 18 Main current 19 Upstream edge of the inner circumferential surface 13 20 air conditioning units 21 Motor vehicle

Claims

A fan (1) with a fan wheel (2) with fan blades (3) and a cover ring (4) surrounding the fan wheel (2) at its outer edge, characterized in that: - the fan wheel (2) has a mantle ring (6) enclosing the fan blades (3) at their outer end; - the mantle ring (6) has an outer circumferential side (11) and the cover ring (4) has an inner circumferential side (13); - the outer circumferential side (11) is arranged opposite the inner circumferential side (13); - a projection (14) directed towards the outer circumferential side (11) of the mantle ring (6) is arranged on the inner circumferential side (13) of the cover ring (4). Fan (1) according to claim 1, characterized in that: - an outwardly projecting ring collar (8) extends from the mantle ring (6) on an upstream side (7); - the mantle ring (6) and the ring collar (8) define a corner region (9) with a first end face (10) and the outer circumferential side (11); - the cover ring (4) has a contour formed substantially complementary to this corner region (9) with a second end face (12) and the inner circumferential side (13); - the first end face (10) is arranged opposite the second end face (12). Fan (1) according to claim 1 or 2, characterized in that the inner circumferential side (13) of the cover ring (4) has an axial length ZW, and that a radial distance GH between the inner circumferential side (13) and the outer circumferential side (11) is in particular approximately 6.0 mm. Fan (1) according to claim 3, characterized in that an axial length RZ2 of the elevation (14) satisfies the following condition 0.15 * ZW < RZ2 < 0.40 * ZW . Fan (1) according to claim 3 or 4, characterized in that a radial height RZ3 of the elevation (14) satisfies the following condition 0.05 * GH < RZ3 < 0.40 * GH . Fan (1) according to one of claims 3 to 5, characterized in that a distance RZ1 of the protrusion (14) from a downstream edge (19) of the inner circumferential side (13) of the cover ring (4) satisfies the following condition; 0.03 * ZW < RZ1 < 0.30 * ZW . Fan (1) according to one of the preceding claims, characterized in that the projection (14) is formed integrally with the cover ring (4), in particular as a one-piece injection-molded plastic part. Fan (1) according to one of the preceding claims, characterized in that an upstream end face (16) and an outstream end face (17) of the protrusion (14) run obliquely to the inner circumferential surface (13). Fan (1) according to one of claims 2 to 8, characterized in that the inner circumferential side (13) runs parallel to the outer circumferential side (11), and / or that the first end face (10) runs parallel to the second end face (12). Air conditioning device (20) for a motor vehicle (21) with a fan (1) according to one of the preceding claims.

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