EP2177769B1 - Radial fan casing - Google Patents

Description

The invention relates to a radial fan housing according to the preamble of claim 1. The invention further relates to a radial fan and a vehicle air conditioning system and a vehicle.

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

Basically, different types of blowers or fans 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 essentially closed rooms, such as, for example, building interiors or vehicle interiors. A particularly common area of application here is the interior of motor vehicles, such as, for example, passenger cars, commercial vehicles or buses.

When it comes to ventilation or air conditioning of indoor spaces, there are usually high comfort requirements. With these comfort requirements, the lowest possible operating noise of the system is desirable. Radial fans are mostly used for indoor air conditioning, as these can provide sufficient pressure build-up for air conditioning applications, especially in relation to axial fans.

Although radial fans have been successively improved over the years, they still produce a clearly perceptible operating noise, especially with a higher air flow through the radial fan. Low-frequency noise components are particularly problematic. Such low-frequency noise components are usually perceived by people as particularly unpleasant. The operating noises that arise can be problematic in particular in the case of recirculating-air operation of motor vehicle air conditioning systems, since the operating noises of the radial fan can then get particularly easily into the passenger compartment via the intake opening of the blower.

Various measures have already been proposed in order to reduce the operating noises that occur with radial fans. So was in US 6,821,088 B2 proposed, for example, to arrange the wall for the spiral-shaped receiving space of the radial fan wheel obliquely to the outer contour of the radial fan wheel in a certain angular range. In EP 0 627 561 B1 It was proposed to provide a flat 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 blower with a tongue edge and a lead-out bead, the lead-out bead being arranged between the housing opening of the air outlet and the opening of the air inlet, is approximately tangential to the opening of the air inlet and runs essentially in a straight line in the direction of the air outlet opening.

The EP 1 462 658 A2 discloses a radial fan for an air supply of a heating burner of a building heater with the features of the preamble of claim 1.

The DE 100 17 808 B4 discloses a housing for a radial fan with the features of the preamble of claim 1.

The EP 1 857 683 A2 discloses a radial fan housing having the features of the preamble of claim 1.

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

The object of the invention is therefore to propose a radial blower housing of a low-noise radial blower, and to provide a radial blower, a vehicle air conditioning system and a vehicle, which comprise such a radial blower housing.

For this purpose, a radial fan housing with the features of claim 1 is proposed.

The air outlet can in particular be designed in the form of a socket or tube and in particular lead at least approximately tangentially away from the receiving recess for the radial impeller. The cross section of the air outlet can for example be round, D-shaped (semicircular) or rectangular. The air intake for the radial fan housing takes place, for example, in the axial direction (corresponds to the direction of the axis of rotation of the radial fan wheel). However, it is readily possible to provide a type of air intake hood in the area of the air intake side of the radial impeller in which an air intake opening is provided that is arranged perpendicular to the axial direction (or tangentially and / or radially (relative to the radial fan wheel)). This makes it possible to at least partially suck in air in the tangential and / or radial direction. For example, it is conceivable to use the tangential and / or radial air intake opening for air intake in a recirculation position, while an axial air intake is used for air intake in an outside air position becomes. Of course, intermediate positions are also possible and / or it is possible to interchange the suction directions. At first glance, the proposed design of the air guiding device appears to be problematic. This is because the inner wall of the receiving recess is “unnecessarily” lengthened, so that the resistance for the outflowing air is increased and / or the outflow cross section for the air emerging on the outside of the radial fan is “unnecessarily” reduced at least in some areas. This usually means that the increased air resistance has to be compensated for with a higher power of the radial impeller and / or the air speeds that occur increase, which in turn usually results in increased operating noise of the radial fan. Surprisingly, however, the inventors have found that the operating noise of the radial fan can on the contrary decrease with the proposed design of the air guiding device, with the low-frequency frequency range in particular often being 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 essentially continues the contour of the air outlet. The side of the air guiding device facing the air outlet generally corresponds to the side of the air guiding device facing away from the receiving recess. In this way it is possible to largely avoid unnecessary edges in the area of the air outlet, which can lead to air turbulence, for example. Air turbulence can usually lead to undesirable additional air resistance and / or additional operating noises. With the proposed training, however, it is generally possible to influence the air flow in such a way that the operating noise can often be reduced. The air guiding device typically has a wedge-like, a tongue-like and / or a V-shaped structure in the proposed training option. The resulting wedge, respectively the resulting tongue can be made solid in any way or can also be provided with a cavity to save material. The corresponding structure can also be “rounded” or “bent” or curved, in particular on its side facing the receiving recess, so that it can, for example, follow the corresponding section of a circularly shaped receiving recess.

According to the invention, the at least one receiving recess has a spiral shape. This makes it possible to take into account the increasing air volume flow along the outside of the radial fan wheel by providing an increasing air passage cross section. With such an embodiment, it is generally possible to operate the radial fan with a particularly low output and / or to reduce the operating noise again.

Tests 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. Tests have shown that such an arrangement is surprisingly particularly noise-reducing, in particular with regard to the low-frequency noise component. Particularly good results have generally been achieved when the air guiding device is arranged on the side of the blower housing facing the air intake opening. In some experiments, conversely, better results have been achieved if the air guiding device is arranged on the side of the blower housing facing away from the air intake opening.

It is also possible to design the at least one air guiding device such that it has an oblique front edge at least in sections, which, in particular at least in some areas, 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 particularly in the specified angular ranges an often particularly strong noise reduction, in particular with regard to the low-frequency noise component, can result. The angle of attack is defined as the angle between the front 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 wheel and perpendicular to the air outflow direction in the air outlet area.

According to the invention, the front edge of the at least one air guiding device runs in a straight line at a constant angle of attack. Although it is often assumed that erratic (random) surface structures and / or surface structures having certain patterns lead to a particularly effective reduction in noise, it has surprisingly been found in the present case that, on the contrary, an at least essentially straight-line shape and / or an essentially smooth surface structure is special can have a noise-reducing effect. Of course, it can also prove to be advantageous in certain application examples if, on the contrary, erratic (random) surface structures and / or surface structures having certain patterns are provided at least in some areas. In particular, it is possible for the air-guiding device to be designed at least in regions with a wavy and / or with a stepped front edge.

According to the invention, the height of the 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 is preferably between 20% and 80%, more preferably between 30% and 70%, particularly preferably between 40% and 60%, in particular between 45% and 55%. Have here too Experiments have shown that the values mentioned can typically lead to a particularly strong reduction in noise, in particular in the low-frequency spectrum.

According to the invention, the at least one air guiding device has a rounded upper side, at least in some areas. Here, too, tests have shown that the proposed shape can generally lead to particularly low operating noises of the radial fan, in particular in the low-frequency noise range. Such a rounded design can be realized in particular in the form of a semi-circular segment. In particular, rectilinear wall areas can adjoin the semicircular segment. This can result in an approximately "D" -shaped shape (which in particular can have relatively long straight legs). In particular, it is possible that the radius of the semicircular segment approximately corresponds to the wall height of the rectilinear wall areas. On the one hand, it is possible that the radius of the semicircular segment changes in accordance with the position of the respective semicircular segment in the longitudinal direction of the air guiding device, corresponding to the height of the respective rectilinear wall region. However, it is also possible that the radius remains largely constant, but the angular range of the circular segment changes (i.e. there is no longer a semicircular segment; usually the angular range will be <180 °). Of course, it is also possible that only circular segments with an angular range of, for example, <180 ° are provided along the entire air guiding device. Mixed forms can of course also be realized. It is furthermore possible for the transition to possibly adjacent rectilinear wall regions to take place 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 can also prove to be useful if at least one air guiding device, at least in some areas, is essentially flat Has top. Even with such a shape, a particularly strong reduction in noise can result in part.

Another preferred embodiment of the radial fan housing is obtained if the suction direction is 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. Here too, tests have shown that the proposed construction can generally result in particularly low operating noise, in particular in the low-frequency noise spectrum. In addition, it is possible to particularly effectively reduce the proportion of the operating noise generated by the blower (in particular its low-frequency frequency component) that is passed on into the vehicle interior, particularly when the motor vehicle air conditioning system is operated in a recirculating air mode.

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

Furthermore, a vehicle air conditioning system, in particular a motor vehicle air conditioning system, is proposed which has at least one radial fan housing according to the structure described above and / or a radial blower 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 fan housing with the structure described above and / or at least one radial fan 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 fan housing, the radial fan or the vehicle air conditioning system in an analogous manner. The vehicle can be an aircraft, a watercraft and / or a land vehicle (rail-bound / non-rail-bound) in any way.

• 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; und
• Fig. 6: ein zweites Ausführungsbeispiel für ein Radiallüftergehäuse mit Luftleitzunge.

The invention is described in more detail below on the basis of exemplary embodiments and with reference to the accompanying drawings. 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 tongue in plan view from above;
• Fig. 4 : The embodiment of a fan tongue seen in a plan view from the side;
• Figure 5 : a first embodiment for a radial fan housing with air duct; and
• Fig. 6 : a second embodiment for a radial fan housing with air duct.

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

The branching or guiding of the air flow into the air outlet duct 9 takes place in a manner known per se with the aid of a dividing bead 10. On the side of the dividing bead 10 opposite the air outlet duct 9, part of the spirally shaped 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 delimited by the outside 17 of the radial fan wheel.

How one Fig. 1 As can be seen clearly, an air guiding device, which in the present exemplary embodiment is designed as an air guiding tongue 4, is arranged in the area of the separating bead 10 in the air flow direction. In the exemplary embodiment shown here, the height of the air guide tongue 4 is 50% (half) of the total height of the pressure chamber 6. The pressure chamber 6, the receiving area 5 for the radial fan wheel 3 and the height of the air outlet duct 9 are chosen to be essentially identical in the exemplary embodiment shown. It should be noted that in Fig. 1 only the upper (suction side) half 7 of the radial fan housing 2 can be seen. Part of the height of the pressure chamber 6 is, however, also by the in Fig. 1 Lower half 12 of the radial fan housing 2, not shown, is formed. The air duct 4, as also in Fig. 1 is shown, a substantially semicircular shaped top 13. The inside 14 of the air guide tongue 4 essentially continues the contour of the pressure chamber wall 11 beyond the area of the separating bead 10. In an analogous manner, the outside 15 of the air guiding tongue 4 continues the boundary wall 18 of the air outlet duct 9 located on the other side of the dividing bead 10 beyond the area of the dividing bead 10. Since the air duct 4 is formed in the exemplary embodiment shown here as a separate component, which can be latched, for example with the aid of appropriately designed locking means, with the upper half 7 of the radial fan housing 2, the transition between the pressure chamber wall 11 and the inside 14 of the air duct 4 or the corresponding boundary wall 18 of the air outlet duct 9 and the outside 15 of the air guide tongue 4 are not completely flat. However, this small unevenness only influences the functioning of the air guide tongue 4 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 systems. This applies not only to a service solution for units that are already in operation, but also to the new construction of air conditioning systems, since existing molds can still be used.

Of course, it is also possible for the air guiding tongue 4 to be formed integrally with (parts) of the radial fan housing 2. For example, it is possible to design the air guide tongue 4 simultaneously 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 produced by an injection molding process, while at the same time the air duct tongue 4 is molded. As a result, it is in particular also possible to make the transition between the pressure chamber wall 11 and the inside 14 of the air duct 4 or the corresponding boundary wall 18 of the air outlet duct 9 and the outside 15 of the air duct 4 largely flat.

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

In Fig. 2 are the in Fig. 1 conditions shown in another perspective view. In Fig. 2 the transition of the boundary wall 18 of the air outlet duct 9 and the outside 15 of the air duct 4 can be seen in particular. In addition, in Fig. 2 to recognize the radial fan wheel 3 which is inserted within the receiving area 5 provided for the radial fan wheel 3. As already mentioned, the outer side 17 of the radial fan wheel 3 defines the inner limit of the pressure space 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. As a reminder: In the 1 to 3 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 inside 14 of the air guide tongue 4 and the outside 17 of the radial fan wheel 3. In this area, the gap 19 delimits part of the pressure space 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 guiding tongue 4, including the definition of the angle of attack a, can be clearly seen here. As already mentioned, the height h of the air guide tongue 4 in the exemplary embodiment shown here is 50% of the height H of the receiving area 5 for the radial fan wheel 3.

In Fig. 5 The radial fan housing 2 of the radial fan 1 is shown with both housing halves 7, 12, that is to say the upper housing half 7 and the lower housing half 12. At the in Fig. 5 selected view is the upper housing half 7 in the drawing below. For purposes of illustration, in Fig. 5 the radial fan wheel 3 is not shown.

The receiving area 5 for the radial fan wheel 3, the pressure chamber 6, part of the pressure chamber wall 11 and the air duct 4 can be seen through the access opening 20.

In the fully assembled state, the access opening 20 is closed by a cover. There is a through opening in the cover for the drive shaft of the radial fan wheel 3. The radial fan wheel 3 can be set in rotation by means of an electric motor 21, for example, from the outside via the drive shaft.

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 2.

In Fig. 6 the radial fan housing 2 of the radial fan 2 is provided with an air intake 25. The air intake 25 is mounted on the upper half 7 of the radial fan housing 2. Air is drawn into the air inlet opening 26 of the air outlet connection 25 in the air suction direction 22. In the air intake port 25, the intake air is deflected downward by 90 ° and thus enters the air intake opening 8 of the radial fan wheel 3. The air is transported from the radial fan wheel 3 to the outside into the pressure chamber 6 of the radial fan housing 2. For this purpose, the radial fan wheel 3 is rotated by the electric motor 21. The direction of rotation is in Fig. 6 construction shown counterclockwise, which in Fig. 6 is indicated by an arrow.

The air conveyed by the radial fan wheel 3 then leaves the pressure chamber 6 via the air outlet duct 9 in the air outlet direction 23. The air inlet direction 22 and the air outlet direction 23 are in FIG 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 also depends on the direction of rotation 24 of the fan wheel 3.

Tests 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 from 250 ° to 270 °. This applies in particular to the low-frequency range of the generated frequency spectrum.

Claims (7)

1. A radial fan housing (2) for the air-conditioning system of a motor vehicle, having at least one receiving recess (5) for receiving a radial fan wheel (3), at least one air outlet (9) with a height (H') and at least one air guiding device (4) for guiding the air flow from the receiving recess (5) to the air outlet (9), wherein the at least one receiving recess (5) is of helical design, wherein the at least one air guiding device (4) has a height (h) and the receiving recess (5) has a height (H), wherein the height (h) of the at least one air guiding device (4) is lower than the height (H) of the at least one receiving recess (5) and/or than the height (H') of the at least one air outlet (9) and is 20% or 80% thereof, and wherein the at least one air guiding device (4) has, at least in some areas, a rounded upper side (13), characterised in that the air guiding device (4) continues the contour (11) of the receiving recess (5) at least on its inside (14) facing the receiving recess (5), and in that the air guiding device (4) runs tangentially to the receiving recess (5) on its side (15) facing the air outlet (9) and continues the contour (18) of the air outlet (9) and the air guiding device (4) has a leading edge, wherein the leading edge (13) of the at least one air guiding device (4) runs straight at a constant angle of attack (α).
2. The radial fan housing (2) according to claim 1, characterised in that at least one air guiding device (4) is arranged in an asymmetrical manner, in particular laterally, in at least one receiving recess (5) and/or relative to at least one air outlet (9) .
3. The radial fan housing (2) according to claim 1 or 2, characterised in that at least one air guiding device (4) has, at least in some areas, an inclined leading edge (13) which has, in particular at least in some areas, an angle of attack (α) of 45° to 85°, preferably 55° to 75°, particularly preferably 60° to 70°, in particular 63° to 67°.
4. The radial fan housing (2) according to one of the preceding claims, characterised in that air is drawn into the air inlet opening of the air outlet stud in an air intake direction, wherein the intake direction (22) is at an angle (β) of 210° to 310°, preferably 220° to 300°, further preferably 230° to 290°, particularly preferably 240° to 280°, in particular 250° to 270° to the outlet direction (23).
5. A radial fan (1), having at least one housing arrangement (2) and at least one radial fan wheel (3), characterised by at least one radial fan housing (2) according to one of claims 1 to 4.
6. A vehicle air-conditioning system, in particular a motor vehicle air-conditioning system, characterised by at least one radial fan housing (2) according to one of claims 1 to 4 and/or at least one radial fan (1) according to claim 5.
7. A vehicle, in particular a motor vehicle, characterised by at least one radial fan housing (2) according to one of claims 1 to 4 and/or at least one radial fan (1) according to claim 5 and/or at least one vehicle air-conditioning system according to claim 6.

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