EP2177769A2 - Radial fan casing - Google Patents

Abstract

The housing (2) has a spiral-shaped accommodating recess (5) for accommodating a radial fan wheel, and an air conductive guide (4) for guiding air flow from the recess to an air outlet (9). The guide sustains a contour (11) of the recess on an inner side (14) of the guide, where the inner side faces the recess. The guide has an inclined leading edge (13) with a blade angle (alpha) that amounts to 63 degrees to 67 degrees, where the leading edge linearly runs at the constant blade angle.

Description

The invention relates to a radial fan housing, which has at least one receiving recess for receiving a radial fan wheel, at least one air outlet and at least one air guide for guiding the air flow from the receiving recess toward the air outlet. The invention further relates to a radial fan, a vehicle air conditioning system and a vehicle.

In many fields of technology, it is necessary to generate a gas flow - usually an air flow - targeted. Fans or blowers are used for this purpose. These convert mechanical energy, which is supplied for example by an electric motor, into a gas flow (usually an air flow).

Basically, different types of blowers or ventilation are known, which are also used in practice. Typical designs are, for example, axial fans or radial fans.

A technical field in which such blowers or fans are used is the ventilation or air conditioning of substantially enclosed spaces, such as, for example, of building interiors or vehicle interiors. A particularly frequent field of use are interior spaces of motor vehicles, such as passenger cars, commercial vehicles or buses and coaches.

In the ventilation and air conditioning of interiors are usually high comfort requirements. With these comfort requirements, the lowest possible operating noise of the system is desired. In the air conditioning of interior spaces mostly radial fans are used, since these can provide a pressure build-up sufficient for air conditioning applications, in particular in relation to axial fans.

Although radial fans have been successively improved over the years, they still produce a noticeably audible operating noise, especially with a higher airflow through the radial fan. Particularly problematic are low-frequency noise components. Such low-frequency noise components are usually perceived by persons as particularly unpleasant. The resulting operating noise can be problematic especially in a recirculation mode of motor vehicle air conditioning systems, since then the operating noise of the radial fan can easily get into the passenger compartment via the suction port of the blower.

In order to reduce the resulting operating noise in radial fans have been proposed different measures. So was in US 6,821,088 B2 For example, proposed to arrange the wall for the spiral receiving space of the radial fan in a certain angular range obliquely to the outer contour of the Radialzuffterrads. In EP 0 627 561 B1 It has been proposed to provide a flat-shaped housing tongue with a symmetrical, wave-like front edge in a radial fan. In DE 100 17 808 B4 It is proposed to provide the housing of a radial fan with a tongue edge and a Ausleitwulst, wherein the Ausleitwulst is disposed between the housing opening of the air outlet and the opening of the air inlet, approximately tangent to the opening of the air inlet and extends substantially straight in the direction of air outlet.

However, there is still a need for low-noise radial fans, which in particular have the lowest possible proportion of low-frequency operating noise.

The object of the invention is thus to propose a low-noise radial fan.

For this purpose, a radial fan housing, in particular a radial fan housing for the air conditioning system of a motor vehicle, which has at least one receiving recess for receiving a Radialgebläserads, at least one air outlet and at least one air guide for guiding the air flow from the receiving recess toward the air outlet, to the effect that the air guide at least on its the receiving recess facing inside the contour of the receiving recess substantially continues. The air outlet may in particular be designed like a nozzle or tube-like and in particular lead away at least approximately tangentially from the receiving recess for the Radialgebläserad. The cross section of the air outlet may, for example, be round, D-shaped (semicircular) or rectangular. The air intake for the radial fan housing, for example, in the axial direction (corresponds to the direction of the axis of rotation of the Radialzuffterrads). However, it is readily possible in the area of the air intake side of the radial fan wheel to provide a type of air intake hood, in which a perpendicular to the axial direction (or tangentially and / or radially) arranged (seen relative to the radial fan) air intake opening is provided. This makes it possible, at least partially to suck air in the tangential and / or radial direction. For example, it is conceivable to use the tangential and / or radial air intake opening for the air intake at a circulating air position, while an axial air intake for the air intake is used at an outside air position. Of course, intermediate positions are possible and / or it is possible to reverse the suction. The proposed design of the louver seems to be problematic at first glance. For the inner wall of the receiving recess is "unnecessarily" extended, so that the resistance for the outflowing air is increased and / or the outflow cross section for the exiting at the radial fan outside air is at least partially "unnecessarily" reduced. This usually leads to the fact that the increased air resistance must be compensated with a higher power of the radial impeller and / or the air speeds occurring become higher, which in turn usually has increased operating noise of the radial blower result. Surprisingly, however, the inventors have found that the operating noise of the radial fan with the proposed design of the louver on the contrary can decrease, often being particularly particularly the low-frequency frequency range is particularly strongly attenuated.

It is advantageous if at least one air guiding device on its side facing the air outlet extends at least substantially tangentially to the receiving recess and / or at least substantially continues the contour of the air outlet. The air outlet facing the side of the louver corresponds to the side facing away from the receiving recess side of the louver as a rule. In this way it is possible in the area of the air outlet unnecessary edges, for example lead to air turbulence, largely avoided. Typically, air turbulence may result in undesirable additional air resistance and / or additional operating noise. With the proposed training, however, it is usually possible to influence the air flow so that often the operating noise can be reduced. The air guiding device typically has a wedge-like, a tongue-like and / or a V-shaped structure in the proposed embodiment. The resulting wedge or the resulting tongue can be massively performed in any way or can also be provided to save material with a cavity. The corresponding structure can also be "rounded" or "bent" or curved on its side facing the receiving recess, for example, so that it can follow, for example, the corresponding section of a circular receiving recess.

It is also useful if at least one receiving recess is formed spirally. This makes it possible to take into account the increase in the air volume flow along the outside of the radial fan by providing an increasing air passage cross-section. With such a training manner, it is usually possible to operate the radial fan with a particularly low power and / or to reduce the operating noise again.

Experiments have shown that it is particularly useful if at least one air guiding device is arranged asymmetrically, in particular laterally, in at least one receiving recess and / or with respect to at least one air outlet. Experiments have shown that such an arrangement is surprisingly particularly noise-sensitive, in particular with regard to the low-frequency noise component. Particularly good results have usually then set when the louver is arranged on the air intake opening facing side of the fan housing. In some experiments, however, better results were achieved, conversely, when the air guiding device is arranged on the side of the fan housing facing away from the air intake opening.

It is also possible to design the at least one air guiding device in such a way that it has, at least in sections, an oblique front edge, which in particular at least in places has an angle of attack of 45 ° to 85 °, preferably 55 ° to 75 °, particularly preferably 60 ° to 70 °, in particular 63 ° to 67 °. Experiments have shown that, in particular in the specified angular ranges often a particularly strong noise reduction, in particular with regard to the low-frequency noise component, may result. The angle of attack is defined as the angle between the leading edge of the air device and the axial direction of the radial fan. The axial direction of the radial fan is usually parallel to the axis of rotation of the radial fan and perpendicular to the air outlet in the air outlet.

It is particularly useful if the leading edge of at least one air guiding device extends substantially rectilinearly at a substantially constant angle of attack. Although it is often assumed that erratic (random) surface structures and / or surface patterns having particular patterns lead to a particularly effective noise reduction, it has surprisingly been found here that, on the contrary, an at least substantially rectilinear shape and / or a substantially smooth surface structure are particularly noise-negative effect. Of course, in certain application examples, it may also be advantageous if, on the contrary, at least in some areas erratic (random) surface structures and / or surface patterns having certain patterns are provided become. In particular, it is possible that the air guiding device is formed at least in regions with a wave-shaped and / or with a stepped front edge.

A further preferred embodiment results if the height of at least one air guiding device is less than the height of at least one receiving recess and / or at least one air outlet, and preferably between 20% and 80%, more preferably between 30% and 70%, particularly preferably between 40 % and 60%, in particular between 45% and 55%. Again, experiments have shown that the values mentioned can typically lead to a particularly strong noise reduction, especially in the low-frequency spectrum.

It is also useful if at least one air guide at least partially has a rounded trained top. Here too, it has been found by experiments that the proposed shaping can generally lead to particularly low operating noise of the radial fan, in particular in the low-frequency noise region. Such a rounded configuration can be realized in particular in the form of a semicircular segment. In particular, rectilinear wall regions can adjoin the semicircular segment. This can result in an approximately "D" -like shape (which may in particular have relatively long straight legs). In particular, it is possible that the radius of the semicircular segment corresponds approximately to the wall height of the rectilinear wall areas. It is possible, on the one hand, that the radius of the semicircular segment changes corresponding to the position of the respective semicircular segment in the longitudinal direction of the louver, corresponding to the height of the respective rectilinear wall region. It is also possible, however, that the radius remains largely constant, but that the angular range of the circle segment changes (that is, there is no longer a semicircle segment, in most cases the angular range will be <180 °). It is also possible to work independently that along the entire air guide only circle segments are provided with an angular range of for example <180 °. Of course, mixed forms can also be realized. It is also possible that the transition into optionally adjacent rectilinear wall regions by means of a sharp edge and / or by means of a rounded transition region. It should be pointed out that in some cases it may also prove expedient if at least one air guiding device has an essentially flat upper side, at least in regions. Even with such a shape can result in part a particularly strong noise reduction.

A further preferred embodiment of the radial fan housing is obtained when the suction direction at an angle of 210 ° to 310 °, preferably 220 ° to 300 °, more preferably 230 ° to 290 °, particularly preferably 240 ° to 280 °, in particular 250 ° to 270 ° to the outlet direction. Again, experiments have shown that with the proposed construction usually a very low operating noise, especially in the low-frequency noise spectrum, may result. In addition, it is possible to reduce the proportion of the operating noise generated by the fan (in particular its low-frequency frequency component), which is forwarded into the vehicle interior, in particular also in a recirculation mode of the motor vehicle air conditioning particularly effective.

Furthermore, a radial fan is proposed with at least one housing device and at least one radial fan, which has at least one radial fan housing according to the structure described above. The radial fan then has the advantages and properties already described in connection with the radial blower housing in an analogous manner.

Furthermore, a vehicle air conditioning system, in particular an automotive air conditioning system is proposed which has at least one radial fan housing according to the structure described above and / or a radial fan with the structure described above. The vehicle air conditioning system then has the advantages and properties already mentioned in connection with the radial fan housing and / or the radial fan in an analogous manner.

In addition, a vehicle, in particular a motor vehicle is proposed, which has at least one radial blower housing with the structure described above and / or at least one radial blower with the structure described above and / or at least one vehicle air conditioning system with the structure described above. The vehicle then has the properties and advantages already described in connection with the radial blower housing, the radial blower or the vehicle air conditioning system in an analogous manner. The vehicle may be any aircraft, vessel, and / or land vehicle (railbound / non-railbound).

• Fig. 1: ein Ausführungsbeispiel einer Luftleitzunge in einer ersten perspektivischen Ansicht;
• Fig. 2: das Ausführungsbeispiel einer Luftleitzunge in einer zweiten perspektivischen Ansicht;
• Fig. 3: das Ausführungsbeispiel einer Lüfterzunge in Draufsicht von oben;
• Fig. 4: das Ausführungsbeispiel einer Lüfterzunge in einer Draufsicht von der Seite aus gesehen;
• Fig.5: ein erstes Ausführungsbeispiel für ein Radialgebläsegehäuse mit Luftleitzunge;
• Fig. 6: ein zweites Ausführungsbeispiel für ein Radiallüftergehäuse mit Luftleitzunge.

In the following the invention with reference to embodiments and with reference to the accompanying drawings will be described in more detail. Show it:

• Fig. 1 : An embodiment of an air duct in a first perspective view;
• Fig. 2 : the embodiment of an air duct in a second perspective view;
• Fig. 3 : the embodiment of a fan blade in plan view from above;
• Fig. 4 the embodiment of a fan blade in a plan view seen from the side;
• Figure 5 a first embodiment of a radial fan housing with air ducts;
• Fig. 6 a second embodiment of a radial fan housing with air ducts.

In Fig. 1 a part of a radial fan 1 is shown in perspective view. More specifically, a part of the upper half 7 of the radial fan casing 2 (corresponding to the suction side half of the radial fan casing 2 in the present case) is shown. Fig. 1 shows the area in which the air flow is diverted from the inlet opening, from the receiving area 5 in the radial fan housing 2 of the radial fan 3, or from the pressure chamber 6 located around the radial fan 3 in the radial fan housing 2 to the air outlet opening 9. For the sake of clarity, is in Fig. 1 the radial fan 3, which is around at the in Fig. 1 selected perspective above the air intake opening 8 in the receiving area 5 is not shown.

The branching or guiding of the air flow into the air outlet channel 9 takes place in a manner known per se with the aid of a separating bead 10. On the side of the separating bead 10 lying opposite the air outlet channel 9, a part of the spirally formed pressure chamber wall or housing wall 11 can be seen limits the pressure chamber 6 in a radial direction. In the other direction, the pressure chamber 6 is limited by the outside 17 of the radial fan.

How one Fig. 1 can well, is in the area of the separating bead 10 in the air flow direction upstream of an air guide, which is formed in the present embodiment as Luftleitzunge 4, arranged.

The height of the Luftleitzunge 4 is in the present embodiment shown 50% (half) of the total height of the pressure chamber 6. The pressure chamber 6, the receiving area 5 for the radial fan 3 and the height of the air outlet 9 are selected to be substantially identical in the illustrated embodiment. It should be noted that in Fig. 1 only the upper (suction side) half 7 of the radial fan housing 2 can be seen. However, part of the height of the pressure chamber 6 is also affected by the in Fig. 1 not shown lower half 12 of the radial fan housing 2 is formed. The air duct 4 has, as also in Fig. 1 is shown, a substantially semicircular shaped top 13. The inner side 14 of the air duct 4 essentially continues the contour of the pressure chamber wall 11 beyond the region of the separating bead 10. In an analogous manner, the outside 15 of the air duct 4 continues the boundary wall 18 of the air outlet duct 9 located on the other side of the separating bead 10, beyond the region of the separating bead 10. Since the Luftleitzunge 4 is formed in the present embodiment shown as a separate component, which can be latched like a clip with the aid of appropriately trained latching means with the upper half 7 of the radial fan housing 2, the transition between the pressure chamber wall 11 and the inner side 14 of the air duct 4 and the corresponding boundary wall 18 of the air outlet channel 9 and the outside 15 of the air duct 4 not completely flat. However, this small unevenness influences the mode of operation of the air duct 4 only to a small extent. A particular advantage of the separate design of the air duct 4 is that the air duct 4 can be installed, for example as a retrofit solution in existing air conditioning. This not only applies to a service solution of units already in operation, but also to the construction of new air conditioning systems, since existing molds can continue to be used.

Of course, it is also possible that the Luftleitzunge 4 is formed integrally with (parts) of the radial fan housing 2. For example it is possible to form the air duct 4 at the same time in the course of the manufacturing process of the radial fan housing 2. For example, the upper half 7 of the radial fan housing 2 could be manufactured by an injection molding process, during which the Luftleitzunge 4 is simultaneously formed. This makes it possible in particular to form the transition between the pressure chamber wall 11 and the inner side 14 of the Luftleitzunge 4 or the corresponding boundary wall 18 of the air outlet channel 9 and the outer side 15 of the Luftleitzunge 4 largely flat.

The angle of attack α of the upper side 13 of the air duct 4 is, in particular Fig. 1 and Fig. 4 can be taken as an angle between the top 13 of the air duct 4 and the axial direction 16 of the radial fan housing 2 and the radial fan 1 defined.

In Fig. 2 are the in Fig. 1 represented ratios shown in another perspective view. In Fig. 2 In particular, the transition of the boundary wall 18 of the air outlet channel 9 and the outside 15 of the air duct 4 can be seen. In addition, in Fig. 2 to detect the radial fan 3, which is inserted within the space provided for the radial fan 3 receiving area 5. As already mentioned, the outer side 17 of the radial fan 3 defines the inner boundary of the pressure chamber 6.

In Fig. 3 the installation conditions of the radial fan 1 are shown in a further view. Fig. 3 shows a part of the radial fan 1 in a view from below. Reminder: In the Fig. 1 to 3 in each case the upper half 7 of the radial fan housing 2 is shown. In Fig. 3 In particular, the narrow gap 19 can be seen, which is located between the inner side 14 of the Luftleitzunge 4 and the outer side 17 of the Radialzuffterrads 3. In this area, the gap 19 limits a part of the pressure chamber 6.

In Fig. 4 the installation conditions are shown in a further view, namely seen in a view from the side. In particular, the position and orientation of the upper side 13 of the air duct 4, including the definition of the angle of attack α, can be clearly seen here. As already mentioned, the height h of the air duct 4 in the illustrated embodiment is 50% of the height H of the receiving area 5 for the radial fan 3.

In Fig. 5 is the radial fan housing 2 of the radial fan 1 with two housing halves 7, 12, that is, the upper half of the housing 7 and the lower half of the housing 12 shown. At the in Fig. 5 Selected view is the upper housing half 7 in the drawing below. For illustrative purposes, is in Fig. 5 the radial fan 3 is not shown.

Through the access opening 20, the receiving area 5 for the radial fan 3, the pressure chamber 6, a part of the pressure chamber wall 11 and the Luftleitzunge 4 can be seen.

In the assembled state, the access opening 20 is closed by a lid. In the lid there is a passage opening for the drive shaft of the radial fan 3. About the drive shaft, the radial fan 3, for example, be offset from the outside by means of an electric motor 21 in a rotary motion.

The air intake opening 8 is located opposite the access opening 20, and thus in Fig. 5 in the lower area of the upper half 7 of the radial fan housing second

In Fig. 6 the radial fan housing 2 of the radial fan 2 is provided with an air intake 25. The air intake pipe 25 is mounted on the upper half 7 of the radial fan housing 2. Air becomes in the air intake direction 22 sucked into the air inlet opening 26 of the air outlet nozzle 25, in the air intake 25, the sucked air is deflected by 90 ° downwards, and enters the air intake 8 of the radial fan 3 a. The air is transported from the radial fan 3 to the outside in the pressure chamber 6 of the radial fan housing 2. The radial fan 3 is rotated by the electric motor 21. The direction of rotation is when in Fig. 6 shown construction in the counterclockwise direction, what in Fig. 6 indicated by an arrow.

The air delivered by the radial fan 3 then leaves the pressure chamber 6 via the air outlet channel 9 in the air outlet direction 23. The air inlet direction 22 and the air outlet direction 23 are in Fig. 6 each represented by an arrow. The angle β enclosed by the air intake direction 22 and the air outlet direction 23 defines the air deflection angle β. The size of the air deflection angle β is also dependent on the direction of rotation 24 of the fan wheel 3.

Experiments have shown that the noise-reducing properties of a radial fan 1 provided with a suitable air duct 4 are particularly pronounced when the air deflection angle β is in a range of 250 ° to 270 °. This applies in particular to the low-frequency range of the generated frequency spectrum.

Claims (12)

Radial fan housing (2), in particular for the air conditioning system of a motor vehicle, comprising at least one receiving recess (5) for receiving a radial fan wheel (3), at least one air outlet (9) and at least one air guiding device (4) for guiding the air flow from the receiving recess (5) Towards the air outlet (9), characterized in that the air guiding device (4) at least on the inner side (14) facing the receiving recess (5) at least substantially continues the contour (11) of the receiving recess (5). Radial fan housing (2) according to claim 1, characterized in that at least one air guiding device (4) on its the air outlet (9) facing side (15) at least substantially tangential to the receiving recess (5) and / or the contour (18) of the air outlet (9) at least substantially. Radial fan housing (2) according to claim 1 or 2, characterized in that at least one receiving recess (5) is formed spirally. Radial fan housing (2) according to one of the preceding claims, characterized in that at least one air guiding device (4) asymmetrically, in particular laterally, in at least one receiving recess (5) and / or with respect to at least one air outlet (9) is arranged. Radial blower housing (2) according to one of the preceding claims, characterized in that at least one air guide (4) at least partially an oblique front edge (13), which in particular at least partially an angle (α) of 45 ° to 85 °, preferably 55 ° to 75 °, more preferably 60 ° to 70 °, in particular 63 ° to 67 °. Radial fan housing (2) according to one of the preceding claims, characterized in that the front edge (13) of at least one air guiding device (4) is substantially rectilinearly at a substantially constant angle of attack (α). Radial blower housing (2) according to one of the preceding claims, characterized in that the height (h) of at least one louver (4) is less than the height (H) of at least one receiving recess (5) and / or at least one air outlet (9), and preferably 20% to 80%, more preferably 30% to 70%, particularly preferably 40% to 60%, in particular 45% to 55%. Radial fan housing (2) according to one of the preceding claims, characterized in that at least one air guiding device (4) at least partially has a rounded upper side (13). Radial fan housing (2) according to one of the preceding claims, characterized in that the suction direction (22) at an angle (β) of 210 ° to 310 °, preferably 220 ° to 300 °, more preferred 230 ° to 290 °, more preferably 240 ° to 280 °, in particular 250 ° to 270 ° to the outlet direction (23). Radial fan (1), comprising at least one housing device (2) and at least one radial fan (3), characterized by at least one radial fan housing (2) according to one of claims 1 to 9. Vehicle air conditioning system, in particular motor vehicle air conditioning system, characterized by at least one radial fan housing (2) according to one of claims 1 to 9 and / or at least one radial fan (1) according to claim 10. Vehicle, in particular motor vehicle, characterized by at least one radial fan housing (2) according to one of claims 1 to 9 and / or at least one radial fan (1) according to claim 10 and / or at least one vehicle air conditioning system according to claim 11.

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