Housing for a fan and a fan having a corresponding housing

Abstract

A housing for a fan, preferably an axial or mixed flow fan, which fan comprises an impeller and at least one flow-through area, is characterized in that a plurality of individual, self-supporting guide elements are provided in the outer area of ​​the housing, directly downstream of the impeller or impeller blades, and thus in the flow-through area. The fan has a corresponding housing.

Description

Technical Field

[0001] The present invention relates to a housing for use in a fan, preferably an axial flow fan or a mixed flow fan, the fan comprising an impeller and at least one flow passage region. The present invention also relates to a fan having such a housing.

Background Art

[0002] Fans comprising a drive unit, an impeller and a housing, in particular axial flow fans or mixed flow fans, are in common use. Furthermore, it is known to provide such fans with guide vanes, diffusers, multi-diffusers and combinations thereof in order to influence the flow. In particular, the aim is to achieve high static pressure efficiency.

[0003] In general, the present invention relates to a fan housing and a fan having such a housing, while in particular the present invention relates to a fan and a housing provided therein, the basic structure of which is shown in FIG. 1. For example, an axial flow fan 1 having a housing 2 is described. The guide device 15 may be integrally formed with the housing 2 by injection molding of synthetic resin. For example, the guide device 15 essentially comprises an inner hub ring 4, an outer hub ring 5, inner guide vanes 3 extending therebetween, and outer guide vanes 3a extending between the outer hub ring 5 and the housing 2. In a state where the fan is assembled, since this guide device 15 is disposed in the housing 2 downstream of the impeller (not shown here), an air duct 6 is formed as an outer flow passage region between the guide device 15 or its outer hub ring 5 and the wall of the housing 2. Part of the air flowing out from the impeller is guided through this outer flow passage region or air duct. Another part of the air flowing out from the impeller is guided through the inner flow passage region 7, which is defined in the spanwise view towards the axis of the inner hub ring 4. When viewed towards the outer flow passage region 6, the inner flow passage region 7 is defined by the outer hub ring 5. The inner flow passage region 7 is provided with inner guide blades 3, and these inner guide blades 3 stabilize the swirling flow near the axis flowing out from the impeller by reducing the swirl in the flow. Thereby, the efficiency is improved. The inner hub ring 4 and the outer hub ring 5 extend substantially circumferentially around the axis. The inner hub ring 4 surrounds, for example, an inner accommodation region 8 where the drive motor of the fan is arranged. In order to be able to remove the waste heat generated from the engine, in the inner accommodation region 8, the flow either does not pass through it or only passes through a very small air volume flow rate. The outer flow passage region 6 has a small number of outer guide blades 3a, and these outer guide blades 3a particularly statically connect the outer hub ring 5 to the housing 2. In the inner flow passage region 7, since the number of the outer guide blades 3a is small, the noise further generated as a result of the interaction between the flow flowing out from the impeller and the outer guide blades 3a in this region is small. In the region of the radial gap between the impeller and the housing 2 and the region downstream thereof, a violent swirling flow occurs, and as a result, flow separation occurs on the inner wall of the housing in the region of the impeller and the region downstream thereof. The return flow passing through the radial gap between the impeller and the housing particularly reduces the static pressure efficiency and generates a non-negligible noise. The inner guide blades 3 and the outer guide blades 3a have load-bearing guide blades, that is, they have the function of ensuring the support connection between the housing and the motor.

Summary of the Invention

Problems to be Solved by the Invention

[0004] The present invention is based on the object of constructing and developing a housing for a fan, particularly for an axial flow fan or a mixed flow fan, such that the effect of the adverse influence of the head gap leakage flow is at least reduced, if not mostly eliminated. The effectiveness of the downstream diffuser is improved, and the blocking effect in the form of the reverse flow region is reduced. The problems occurring in the prior art are solved by means of a simple configuration that differentiates both the housing according to the present invention and the fan according to the present invention from competing products.

Means for Solving the Problems

[0005] The object regarding the housing is achieved by using the features of claim 1 according to the present invention. According to this, the housing of the higher concept is characterized in that a plurality of individual and self - supporting guiding elements are provided in the outer region of the housing directly below the impeller or the impeller blades. The object regarding the fan is achieved by using the features of claim 18.

[0006] The features of the present invention present a simple aspect, according to which, regardless of the specific morphological / structural features of the housing and the fan, individual obstacles are provided downstream of the impeller, and thus downstream of the blades of the impeller, where head gap leakage flow or reverse flow regions may occur, particularly in the outer region of the housing. Since the obstacles are configured as individual and self - supporting guiding elements, they do not belong to an integral or supporting guiding device. These are to be understood as individual structural elements, and the individual and self - supporting guiding elements are formed directly on or within the inner wall of the housing.

[0007] Specifically, the individual and self - supporting guiding elements are formed on the inner wall of the housing by a combination of recesses and protrusions, thereby achieving a special flow effect. With this feature, the shape of the inner wall of the housing can be effectively achieved using self - supporting guiding elements.

[0008] In principle, it is conceivable that individual and self - supporting guiding elements are integrated into the inner wall of the housing when viewed individually. In this case, the housing may be manufactured using injection molding technology or casting of synthetic resin together with the integrated individual and self - supporting guiding elements.

[0009] Alternatively, the individual and self - supporting guiding elements are made of metal or synthetic resin regardless of the material and manufacturing method of the housing, and are attached to the inner wall of the housing using, for example, adhesives or welding.

[0010] In order to achieve a sufficiently good hydrodynamic effect, a sufficient number of self - supporting guiding elements in the range of 20 to 100 are provided according to the dimensions of the housing.

[0011] The individual and self - supporting guiding elements of the housing may be arranged at equal intervals relative to each other over the circumference of the inner wall of the housing. By arranging the self - supporting guiding elements uniformly, in other cases, the swirling flow is effectively stabilized and / or this flow is directed more in the flow direction. As a result, the turbulent flow can also be removed from the impeller more quickly.

[0012] Between the two support guiding blades of the guiding device, a plurality of individual and self - supporting guiding elements, for example, 4 to 12 self - supporting guiding elements, are arranged radially from the housing wall and, if possible, protrude at a predetermined angle so that the positions of the individual and self - supporting guiding elements alternate with the circumferential position of the support guiding blades of the guiding device. In any case, the individual and self - supporting guiding elements are essentially attached directly downstream of the impeller, where it is important to counteract the backflow against the actual transport direction.

[0013] Individual and self - supporting guiding elements may have the same configuration and project from the inner wall of the housing at the same angle. It is also conceivable that the individual and self - supporting guiding elements are arranged alternately at an oblique angle and project from the inner wall of the housing in different directions accordingly.

[0014] Based on a specific housing having a substantially circular cross - section with a substantially cylindrical, preferably annular, flow region in which the impeller is arranged, the individual and self - supporting guiding elements are formed at the end or downstream of the cylindrical flow - through region, preferably at the start of the widening diffuser region or at the transition between these two regions. It is important to be in the immediate vicinity of the impeller. The self - supporting guiding elements cancel any flow separation on the inner wall of the housing downstream of the impeller, thereby obtaining a low - noise fan with high efficiency, that is, the flow is stabilized by the individual and self - supporting guiding elements on the inner wall of the housing. Furthermore, by providing the individual and self - supporting guiding elements, the effect of the diffuser, which may be integrated into the housing and connected to the above - mentioned cylindrical flow - through region of the housing wall, is improved.

[0015] Specifically, the individual and self - supporting guiding elements extend radially from the inner wall of the housing, slightly smaller or slightly larger than the annular gap between the blades of the impeller and the inner wall of the housing. The ratio of the height of the individual and self - supporting guiding elements to the width of the annular gap may be in the range of 0.8 to 3.0. It is advantageous that the axial distance between the individual and self - supporting guiding elements on the housing wall and the blades of the impeller is less than 8 times the width of the gap.

[0016] In the above - mentioned form, simply providing the individual and self - supporting guiding elements greatly contributes to the stabilization of the swirling flow in the region downstream of the radial gap between the impeller and the housing in other cases. Further optimization is possible due to the specific shape of the individual and self - supporting guiding elements. The individual and self - supporting guiding elements may have a slightly rounded leading edge and a slightly thin "tapered" trailing edge.

[0017] Basically, the individual and self - supporting guiding elements have a contour shape that substantially corresponds to the contour of an airfoil or an impeller blade. Such features also promote the effect and thus the stabilization of the flow.

[0018] Also, adjacent individual and self - supporting guiding elements have a certain inclination, that is, they are arranged at a certain angle oblique to the longitudinal axis. On the other hand, it is advantageous if adjacent individual and self - supporting guiding elements in the circumferential direction do not overlap in the circumferential direction or at least have a small distance from each other in the projection view onto a plane perpendicular to the fan axis. This facilitates removal from casting tools, for example, injection molding tools.

[0019] At the open end, the individual and self - supporting guiding elements may be configured in various ways depending on the specific installation situation and dimensions. The individual and self - supporting guiding elements may have a non - sharp, angular, rounded, chamfered or angled open end, which has a significant influence on the air flow. Adjustment to the overall structural situation is advantageous.

[0020] Also, the basic object of the claimed fan, in particular, an axial - flow fan or a mixed - flow fan, is achieved by using a housing having the features described in claims 1 to 17. The corresponding description can be omitted by referring to the description of the housing.

[0021] Here, there are various possibilities for advantageously configuring and developing the features of the present invention. For this purpose, on the one hand, the claims dependent on claim 1 are referred to, and on the other hand, the following description of embodiments of the fan according to the present invention based on the drawings is referred to. In connection with the description of the preferred embodiments of the present invention based on the drawings, the preferred embodiments and development forms of this feature will also be generally described.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

[0023] FIG. 1 shows a perspective view of an axial - flow fan 1 having a housing 2 according to the present invention. The guiding device 15 is integrally formed with the housing 2 by injection molding of synthetic resin. In the present embodiment, it essentially consists of an inner hub ring 4, an outer hub ring 5, inner guiding blades 3 extending between them, and outer guiding blades 3a extending between the outer hub ring 5 and the housing 2. In a state where the axial - flow fan 1 according to the present invention is assembled, since this guiding device 15 is arranged in the housing 2 downstream of an impeller (not visible), an air duct (outer - flow passage region) 6 is formed between the guiding device 15 or its outer hub ring 5 and the inner wall of the housing 2, and a part of the air flowing out from the impeller is guided through this air duct 6. Another part of the air flowing out from the impeller is guided through an inner - flow passage region 7, which is limited by the inner hub ring 4 towards the axis in a span - wise view and defined by the outer hub ring 5 towards the outer - flow passage region 6 in a span - wise view. The inner - flow passage region 7 is traversed by inner guiding blades 3 (in this embodiment, 17, preferably 9 to 23), which stabilize the swirling flow near the axis flowing out from the impeller by reducing the twist in the flow. Thereby, the efficiency is improved. The inner hub ring 4 and the outer hub ring 5 extend substantially over the entire circumference around the axis. The inner hub ring 4 surrounds, for example, an inner accommodation region 8 in which a drive motor of the fan is disposed. In order to be able to remove the waste heat generated by the engine, in the inner accommodation region 8, the flow either does not cross or only crosses a small air volume flow rate (0.1% to 2% of the total air volume flow rate). In particular, when driven by a pressure difference between the outflow side and the inflow side, the flow through the inner accommodation region 8 may be against the main transport direction.

[0024] The outer flow passage region 6 has a small number of outer guide blades 3a, and these outer guide blades 3a particularly statically connect the outer hub ring 5 to the housing 2. In this outer flow passage region 6, since the number of the outer guide blades 3a is small, the noise further generated as a result of the interaction between the flow flowing out from the impeller and the outer guide blades 3a is small in this outer flow passage region 6. A large number of self - supporting guide elements 16, in this embodiment, 54, and preferably 30 to 100 self - supporting guide elements 16 are attached to the inner wall of the housing 2. The self - supporting guide elements 16 are integrally connected to the housing 2, for example, by injection molding of synthetic resin. It is also conceivable to be by casting. It is also conceivable to provide self - supporting guide elements made of synthetic resin or metal in the housing by adhesion, welding, etc. The self - supporting guide elements 16 are attached to the region of the housing wall on the inflow side of the guide device 15, but may overlap the guide device 15 in the axial view. It is important that the self - supporting guide elements 16 are attached at a small distance, which is below the axial range of the corresponding self - supporting guide element 16, slightly below the impeller (not shown here) downstream. The self - supporting guide elements 16 have a free end facing in the direction opposite to the wall of the housing 2 and project from the wall of the housing 2 at a relatively small height. The self - supporting guiding element 16 ensures the stabilization of a violent swirling flow according to the point of action in the downstream region of the radial gap between the impeller and the housing 2 (see also Fig. 6 in particular), thus preventing and / or reducing the separation and / or turbulence of the flow on the inner wall of the housing in the region of the impeller and in the region downstream thereof, and helping to at least reduce it or accelerate it and convey it in the flow direction.

[0025] Generally, a fan with a quiet and high - level efficiency can be obtained, that is, thanks to the stabilization of the flow or the acceleration of the flow in the flow direction by the self - supporting guiding element 16 provided on the wall of the housing 2, which can improve the effect of the outer diffusion part 10 integrated with the housing 2.

[0026] Figure 2 shows the axial - flow fan 1 having the housing 2 according to the invention of Figure 1 in a side and plane cross - section passing through the fan axis. The impeller 19, the motor 34 and the guiding device 15 of the axial - flow fan 1 can be easily seen. In the cross - section passing through the guiding device 15, the outer flow - passing region 6 with the outer guiding blade 3a, the inner flow - passing region 7 with the inner guiding blade 3 and the accommodating region 8 in the inner hub ring 4 can be seen. The impeller 19 is arranged upstream of the guiding device 15. During the operation of the axial - flow fan 1, air flows in the direction from left to right in this figure, first through the inlet nozzle 9 integrated with the housing 2, then through the impeller 19, and then is divided into the outer flow - passing region 6 and the inner flow - passing region 7, and the flow is stabilized by the outer guiding blade 3a and the inner guiding blade 3 (in particular, in the inner flow - passing region 7), and the kinetic energy of the flow is converted into pressure energy. In this embodiment, both the inner guiding blade 3 and the outer guiding blade 3a have an inflow edge angle at the inflow - side edge facing the impeller 19, which optimally matches the flow angle of the flow flowing out of the impeller 19 and colliding with the outer guiding blade 3a and the inner guiding blade 3 in the cross - section of the cylinder jacket coaxial with the fan axis. The inflow edge angle measured with respect to the plane passing through the fan axis is in the range of 20° to 70°. The inner guide blade 3 and / or the outer guide blade 3a has a rounded inflow edge and further has a varying thickness, which is shaped similar to an airfoil or a droplet. The self - supporting guide element 16 is attached to the inner wall of the housing 2 in the front region of the guide device 15 in the flow direction or in front of the guide device 15. The self - supporting guide element 16 stabilizes and / or accelerates in the flow direction the flow flowing out from the impeller 19 which is affected by strong torsion in the outer wall region of the housing 2, and prevents or reduces separation or turbulent flow. As a result, the blockage effect of the outer flow passage region 6, which has an adverse effect on efficiency and air output, is prevented or at least reduced by a large relief region.

[0027] In the inner accommodation region 8 of the inner hub ring 4, a fixture 18 for the motor 34 is provided. The motor 34, which is shown schematically, is attached thereto. The guide device 15 connects the motor 34 to the housing 2, and thereby indirectly connects the impeller 19 to the housing 2. The motor 34 is connected to the guide device 15 on the stator side. On the rotor side, the motor 34 is connected to the impeller 19 by a fixture 30. The impeller 19 essentially consists of an inner hub ring 21 and impeller blades 22 attached thereto. The inner hub ring 21 is configured such that the stagger angle of the impeller blades 22 can be adjusted according to the needs of the fan application for which the axial flow fan 1 is used.

[0028] Basically, there are two different support concepts for the motor 34 together with the impeller 19. On the one hand, as shown in this embodiment, a support guide device 15 can be provided. That is, the guide device 15 having an aerodynamic function connects and supports the motor 34 to the housing 2. On the other hand, for example, the motor 34 can be attached to the housing 2 using a purely mechanical connection made of a rod, wire, flat material, or the like. In such a case, the guide device 15 may or may not be provided.

[0029] In other embodiments, the guide device 15 may be configured without having the outer hub ring 5 and / or having only one type of guide blade, which is advantageous in terms of load-bearing capacity.

[0030] It can be seen in FIG. 2 that the support guide blade (here, the outer guide blade 3a) is arranged in the same region as the self-supporting guide element 16 when viewed in the flow direction. As a result, the self-supporting guide element 16 in this embodiment is not uniformly arranged over the circumference, but is repeatedly interrupted by the outer guide blade 3a. In this embodiment, nine, preferably four to twelve, self-supporting guide elements 16 are arranged between two adjacent outer guide blades 3a in the circumferential direction. In other embodiments, the self-supporting guide elements 16 may be uniformly arranged over the circumference or may be arranged non-uniformly in another way.

[0031] FIG. 3 shows the housing 2 of the axial flow fan 1 of FIGS. 1 and 2 in a side and plane section passing through the fan axis. It can be easily seen the outer flow passage region 6 having the outer guide blade 3a and the inner flow passage region 7 having the inner guide blade 3, which are separated by the outer hub ring 5.

[0032] In this embodiment, both the wall of the housing 2 and the inner hub ring 4 have a conical shape toward the outflow end. In this way, the outer diffuser 10 is integrated with the housing 2. Both the inner flow passage region 7 and the outer flow passage region 6 are configured as diffusers having a flow cross-section that widens towards their outflow ends. This is very advantageous with respect to the static pressure efficiency, particularly for axial fans. The outer hub ring 5 of the guide device 15 is also slightly conical in this embodiment and widens slightly radially in the flow direction.

[0033] The inner flow guide wall of the housing 2 essentially has the contour of the inlet nozzle 9, followed by a cylindrical flow passage region 11, and then a diffuser region 10 that opens radially. The impeller extends up to the level of the cylindrical flow passage region 11 at least in most of the impeller region 29 in the flow direction. The self-supporting guide element 16 may be arranged at the end of the cylindrical flow passage region 11 or at the start of the diffuser region 10 or in the transition region between these two regions. In any case, the self-supporting guide element 16 is attached downstream of the impeller 19 or its impeller blades 22 (see FIG. 2). When removing the housing 2 from a casting tool, particularly an injection molding machine for synthetic resin, the self-supporting guide element 16 is arranged completely or mostly within the cylindrical flow passage region 11. On the other hand, with regard to the axial compactness of the axial fan 1, it may be advantageous if the self-supporting guide element 16 is arranged at least mostly within the diffuser region 10, because in that case the diffuser region 10 can be directly adjacent to the impeller 19.

[0034] Advantageously, in the housing 2 and / or the guide device 15, fixtures, such as fixing flanges, used to fix the axial fan to a higher-level system, such as an air conditioning unit, may be incorporated or attached on both the inflow side and the outflow side.

[0035] FIG. 4 shows a perspective view from the outflow side of a further embodiment of the axial fan 1 having a housing according to the invention. In this embodiment, no guiding device is provided downstream of the impeller 19 having the impeller blades 22. To fix the motor 34 to the housing 2, for example, a supporting device (not shown here) made of a rod or a flat material is required to connect the motor 34 and the housing 2. The self - supporting guiding elements 16 are uniformly arranged over the circumference and extend directly below the outer ends of the impeller 22 or its blades on the flow guiding wall inside the housing 2. The housing 2 has an outflow side edge 25 at the outflow side end of the outer diffusion part 10, from where air flows out during operation from the fan 1. The impeller blades 22 are provided with so - called winglets 20, that is, special geometric structures, at their outer ends, and these winglets 20 have a favorable influence on the flow in the outer region of the impeller blades 22 near the housing with respect to the noise radiation and / or the efficiency of the axial - flow fan 1.

[0036] FIG. 5 shows the axial - flow fan 1 having the housing 2 of FIG. 4 in a side and plane section passing through the fan axis. It can be seen that the self - supporting guiding element 16 is directly connected to the impeller 19 or its impeller blades 22 attached to the hub ring 21 in the flow direction, which is approximately from left to right in this figure.

[0037] FIG. 6 shows a detailed view of FIG. 5, in which the region of the self - supporting guiding element 16 on the inner wall of the housing 2 is shown enlarged and further reference signs are attached. The impeller blades 22 of the impeller 19 have their winglets 20 and can be seen at their radially outer ends. Since the impeller blades 22 extend spaced apart from the housing 2 in the cylindrical flow - through region 11, contact of the impeller 19 during operation is excluded. Therefore, a radial gap having a width d12 is formed between the impeller blade 22 and the wall of the housing 2, through which a regular backflow (leakage flow) of air occurs against the actual flow direction. As a result, a flow region having a very high component in the circumferential direction and a low component in the flow direction is locally generated in the vicinity of the wall of the housing 2 in the region of the impeller blade 22. This flow region induces high flow losses and noise radiation, and in particular, may cause a blocking effect on the downstream outer diffuser 10.

[0038] These losses can be significantly reduced by the self - supporting guide element 16 which is very close to the impeller blade 22 and is located downstream of the impeller blade 22. These self - supporting guide elements 16 convert a part of the circumferential velocity component into an axial velocity component, that is, they direct the local flow more axially. Thereby, a reduction in the backflow region in the region of the radial gap having a width d12, and thus a reduction in losses, noise generation and (partial) blocking of the downstream diffuser defined outwardly by the outer diffuser 10 are achieved.

[0039] The self - supporting guide element 16 extends very locally in the radial direction only in the region of the radial gap of the impeller having a width d12 or only a width obtained by multiplying d12 by a small coefficient beyond that. In fact, the self - supporting guide element 16 has a height h23 measured from the wall of the housing 2. The ratio of h23 to d12 is in the range of 0.8 to 3. The axial distance between the self - supporting guide element 16 and the impeller blade 22 on the wall of the housing 2 is less than 8 times the gap width d12.

[0040] In the present embodiment, the self - supporting guide element 16 extends into the region of the outer diffuser 10. In other embodiments, the self - supporting guide element 16 may also extend into the cylindrical flow - through region 11. In this embodiment, when the self-aligning guide element 16 extends into the cylindrical flow-through region 11, it becomes difficult to remove the one-piece cast housing 2. A removal region (not shown) is integrated, which enables removal in a removal direction parallel to the fan axis using an opening / closing tool without the need for an additional sliding member.

[0041] According to the present invention, the self-aligning guide element 16 deflects the intense swirling flow in the region of the housing 2 wall more axially. In other embodiments, other geometric solutions are also conceivable, and the self-aligning guide element is further incorporated, for example, into the contour of the housing in the form of, for example, a recess or a protrusion. It is important that the influence of this flow occurs only in the vicinity of the housing wall and in the immediate vicinity of the impeller blade where an interaction with the leakage flow in the radial gap between the impeller blade and the housing occurs.

[0042] FIG. 7 shows a perspective view from the outflow side of a further embodiment of the housing 2 without a guiding device according to the present invention. Here, the self-aligning guide elements 16 are arranged substantially uniformly over the circumference of the inner wall of the housing 2. On its flow-guiding inner wall, the housing 2 essentially has an inlet nozzle 9, a cylindrical flow-through region 11, and an outer diffuser 10 that terminates at the outflow-side edge 25 of the housing 2.

[0043] FIG. 8 shows a side view in a plane section passing through the axis 26 of the housing 2 of FIG. 7. The self-aligning guide element 16 is arranged approximately in the transition region between the cylindrical flow-through region 11 and the outer diffuser 10, which means that the self-aligning guide element 16 extends across the boundary between the cylindrical flow-through region 11 and the outer diffuser 10, and the transition region is characterized by gradually widening radially in the direction of the flow. In this embodiment, the opening angle in one direction of the contour of the outer diffuser 10 is approximately 12°, and preferably, it is 6° to 18°.

[0044] Figure 9 shows a detailed view of FIG. 8 in the region of the fan axis, in which the region of the individual and self-supporting guide element 16 is shown enlarged and is provided with further reference signs. Since it is a view of a region near the axis at high magnification and (by projection view), a substantially planar cross-section of the wall of the housing 2 can be seen.

[0045] The self-supporting guide element 16 has an inflow edge 13 that is at least substantially rounded and an outlet edge 14 that is thin compared to the other shape. In cross-sectional view, the self-supporting guide element 16 has a substantially airfoil contour shape. In other embodiments, other cross-sectional contours are possible, for example, a thin contour having a substantially constant thickness is possible. The self-supporting guide element 16 has a chord length s31 and an axially extending portion I32. With respect to the value, I32 is small, for example, 0.2% to 5% of the impeller diameter or 10% to 60% of the axially extending portion of the impeller blade. The chord length s31 is approximately 1.2 to 2 times larger than I32. In the circumferential view, the adjacent self-supporting guide elements 16 do not overlap so that the housing 2 can be easily removed from the casting tool. The inflow angle α27 is assigned to the inflow edge 13. This is the local angle between the chord 37 or the extension of its tangent direction there and a line parallel to the axis 26. The outflow angle β28 is assigned to the outflow edge 14. This is the local angle between the skeleton line 37 or the extension of its tangent direction there and a line parallel to the axis 26. The outflow angle β28 is smaller than the inflow angle α27 and is at least 20° smaller. As a result, the swirling flow will be deflected axially. In this case, the self-supporting guide element 16 has a front end 24.

[0046] FIG. 10 shows a further detailed view of FIG. 8 in the region of a cross-section through the upper part of the wall of the housing 2, in which the region of the self-aligning guide element 16 is shown enlarged and further reference numerals are provided. The self-aligning guide element 16 has a blunt free end 24. In the cross-sectional view, when looking along the approximate height of the self-aligning guide element 16, the self-aligning guide element 16 has an approximately rectangular contour. On the other hand, it is advantageous that a rounded transition region 17 is formed with respect to the wall of the housing 2.

[0047] FIG. 11 shows a further embodiment of the housing 2 according to the invention, in which a first type of winglet 38a is provided at the open end of the self-aligning guide element 16, in a detailed view similar to the embodiment of FIG. 10. At the open end of the self-aligning guide element 16, a contour having a thickness of 1 mm to 3 mm projects towards the concave side of the self-aligning guide element 16. In the cross-sectional view, when looking along the approximate height of the self-aligning guide element 16, the self-aligning guide element 16 has an approximately L-shaped contour.

[0048] FIG. 12 shows a further embodiment of the housing 2 according to the invention, in which a second type of winglet 38b is provided at the open end of the self-aligning guide element 16, in a detailed view similar to the embodiment of FIG. 10. On the convexly curved side of the self-aligning guide element 16, a chamfering of one type is formed towards the self-aligning edge, so that the self-aligning guide element 16 tapers towards a point approximately towards its open end. On the other hand, at the outer end, the self-aligning guide element 16 is not completely tapered, but is provided with a very thin end having a thickness at the end.

[0049] FIG. 13 shows a further embodiment of the housing 2 according to the invention, in which a third type of winglet 38c is provided at the open end of the self-aligning guide element 16, in a detailed view similar to the embodiment of FIG. 10. On the concave curved side of the self-supporting guiding element 16, towards the self-supporting edge, due to the formation of one type of rounding, the self-supporting guiding element 16 appears to have a quarter-circular rounding towards its open end. The edge on the convex side of the self-supporting guiding element 16 remains at least substantially tapered.

[0050] To avoid repetition regarding a further embodiment of the fan according to the present invention having the housing according to the present invention, reference is made to the general part of the specification and the appended claims.

[0051] Finally, it is explicitly pointed out that the above-described embodiments of the fan according to the present invention and the housing according to the present invention are only used to illustrate the claimed features and are not intended to limit them to exemplary embodiments.

Explanation of Reference Signs

[0052] 1 ··· Fan 2 ··· Housing 3 ··· Inner guiding blade 3a ··· Outer guiding blade 4 ··· Inner hub ring of the guiding device 5 ··· Outer hub ring of the guiding device 6 ··· Outer flow passage region 7 ··· Inner flow passage region 8 ··· Accommodation region inside the inner hub ring 9 ··· Inlet nozzle 10 ··· Outer diffuser 11 ··· Cylindrical flow passage region of the housing 12 ··· Width d of the radial gap of the impeller 13 ··· Inflow edge of the self-supporting guiding element 14 ··· Outflow edge of the self-supporting guiding element 15 ··· Guiding device 16 ··· Self-supporting guiding element 17 ··· Transition region of the self-supporting guiding element to the housing 18 ··· Fixture of the motor to the guiding device 19 ··· Impeller 20... Winglet of the impeller blade 21... Inner hub ring of the impeller 22... Impeller blade 23... Height h of the self - supporting guide element 24... Front end of the self - supporting guide element 25... Outlet side edge of the housing 26... Shaft of the fan 27... Inflow angle α of the self - supporting guide element 28... Outflow angle β of the self - supporting guide element 29... Region for the impeller 30... Fixture of the motor to the impeller 31... Chord length s of the self - supporting guide element 32... Axial extension part I of the self - supporting guide element 34... Motor 37... Skeleton line of the self - supporting guide element having an extension line in the tangential direction 38a... Winglet of the self - supporting guide element 39b... Winglet of the self - supporting guide element 39c... Winglet of the self - supporting guide element

Claims

1. A housing for a fan, wherein the fan comprises an impeller and at least one flow-through region, a plurality of individual self-supporting guiding elements are provided directly downstream of the impeller or the impeller blades of the impeller, the self-supporting guiding elements extend radially from the inner wall of the housing, being slightly smaller or slightly larger than the width of the annular gap between the impeller blades of the impeller and the inner wall of the housing, the ratio of the height of the self-supporting guiding elements to the width of the annular gap is in the range of 0.8 to 3.0, the axial distance between the self-supporting guiding elements and the impeller blades of the impeller on the inner wall of the housing is less than 8 times the width of the annular gap, the self-supporting guiding elements have a slightly rounded inlet edge and a slightly thin outlet edge, characterized in that the housing.

2. The housing according to claim 1, characterized in that the self-supporting guiding elements are formed directly on or within the inner wall of the housing.

3. The housing according to claim 1 or claim 2, characterized in that the self-supporting guiding elements are formed on the inner wall of the housing by a combination of recesses and protrusions.

4. The housing according to any one of claims 1 to 3, characterized in that the self-supporting guiding elements are integrated with the inner wall of the housing.

5. The housing according to claim 4, characterized in that the housing is formed by injection molding or casting of synthetic resin together with the integrated self-supporting guiding elements.

6. The housing according to any one of claims 1 to 3, characterized in that the self-supporting guiding elements are made of metal or synthetic resin and are adhered to the inner wall of the housing.

7. The housing according to any one of claims 1 to 6, characterized in that the number of the self-supporting guiding elements is in the range of 20 to 100.

8. The housing according to any one of claims 1 to 7, characterized in that the self-supporting guiding elements on the inner wall of the housing are arranged at equal intervals with respect to each other over the circumference of the inner wall of the housing.

9. The housing according to any one of claims 1 to 7, characterized in that the self-supporting guiding elements are arranged non-uniformly over the circumference of the inner wall of the housing.

10. The housing according to claim 9, characterized in that the positions of the self-supporting guiding elements alternate with the supporting guiding blades of the guiding device such that a plurality of self-supporting guiding elements protrude radially from the inner wall of the housing between two supporting guiding blades of the guiding device.

11. The housing according to any one of claims 1 to 10, characterized in that the self-supporting guiding elements are of the same configuration and protrude from the inner wall of the housing at the same angle.

12. The housing having a circular cross-section having a cylindrical flow passage region in which the impeller is disposed, The housing according to any one of claims 1 to 11, characterized in that the self-supporting guiding elements are formed at the end or downstream of the cylindrical flow passage region.

13. The housing according to any one of claims 1 to 12, characterized in that adjacent self-supporting guiding elements do not overlap or have at least a slight gap with respect to each other in a projection view onto a plane perpendicular to the fan axis.

14. The housing according to any one of claims 1 to 13, characterized in that the self-supporting guiding elements have open ends that are not sharp, angular, rounded, chamfered or angled.

15. A fan, characterized in that it has the housing according to any one of claims 1 to 14.

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