EP1741934A1 - Rotor - Google Patents

Abstract

An automobile air conditioning system or heater has a rotating blower fan. The circular fan disc has a central hub with a first inner array of radial blades, and a second outer array of essentially radial blades terminating in an outer ring in-line with silts aligned with the hub axis. Adjacent blades in the outer ring are separated by gaps forming air flow passages which are convergent. The outer blades have a thick leading edge that tapers to a thin cross-section towards the center. The ratio of blade maximum thickness to chord is greater than 0.25. The fan is made of plastic or a light metal.

Description

The invention relates to an impeller, in particular a plastic impeller for a drum rotor radial fan for the heating and air conditioning of a motor vehicle, according to the preamble of claim 1.

Drum rotor centrifugal blowers, which are used for the promotion of air in motor vehicle heaters or automotive air conditioning systems, should be operated at the lowest possible speed level.

Such radial blowers have a forward curved blading and achieve comparable operating points at significantly lower speeds than z. B. Blower with backward curved blading. In the forward curved blading the flow is accelerated and strongly deflected. This kinetic energy is delayed in ideally designed, parallel-walled volute casings and converted into static pressure. Flow separation takes place at the blade channel inlet, and the flow arrives again at the blade channel end. The blading is not or only slightly profiled. The blades are usually massively injection molded (compare left part of Fig. 3, in which the flow path in a blade channel at a conventional, almost unprofiled impeller is shown, wherein on the suction side of the blades a vortex formation can be seen).

The US 3,394,876 discloses a rotary axis rotatable rotor for a tumbler fan having a plurality of spaced apart blades having inner and outer edges and a substantially constant blade thickness. Each blade is curved in planes perpendicular to the axis of rotation, whereby a fluid can be conveyed to the outside. In this case, each blade has a curved inner Anströmbereich with a first small radius of curvature, a curved outer outflow region with a second larger radius of curvature and an interposed portion having a radius of curvature which is greater than the first radius of curvature, but not greater than the second radius of curvature. In this case, the exit region is arranged such that a plane which bears tangentially on the exit region, an angle of less than 15 ° to another plane which bears tangentially on the circle with the axis of rotation as the center. Shorter trained auxiliary blades may be provided in the entry region between the individual blades.

If such a blading is wrongly flown, ie obliquely to the inlet angle of the auxiliary blades, it can be due to detachment of the auxiliary blades to a significant obstruction of the inlet cross-section.
From the EP 1384894 A2 For example, a blade design is known in which an attempt is made to achieve a separation-free blade channel flow through a second blade row, which forms a gap between blade pressure and suction side. This leads to a reliable energy exchange between vane pressure and suction side, as well as gap losses.

It is therefore an object of the invention to provide an improved impeller available, where possible no detachments occur in the blade channel.

This object is achieved by an impeller with the features of claim 1. Advantageous embodiments are the subject of the dependent claims.

According to the invention, an impeller is provided, in particular a plastic impeller for a drum rotor radial fan for the heating and air conditioning of a motor vehicle having a plurality of blades, wherein the flow channel converges between two blades in the flow direction from inside 7 to outside 8 upstream and downstream convergent and the impeller blades strongly profiled is formed. Subregions of the flow channel may also be divergent. The substantially convergent design of the blade channel in conjunction with the strong profiling of the impeller blades allows a substantially separation-free flow in the blade channel, in particular in the inlet region. The flow is accelerated by the strong curvature and sufficient thickness of the blade profile and deflected without detachment in the direction of rotation of the impeller. In a preferred embodiment, the blade channel is formed in its entirety convergent.

The channel length ratio with an inflow and outflow convergent embodiment of the flow channel is preferably between 0.5 and 0.95, in particular between 0.6 and 0.9, more preferably between 0.7 and 0.85.

The impeller preferably has a hub disc whose maximum solid wall thickness is a maximum of 3 mm.

The blades of the impeller are preferably formed strongly profiled. In particular, blades are considered to be highly profiled, in which the ratio of profile thickness to total profile length (profile thickness ratio) is greater than or equal to 0.15, in particular greater than or equal to 0.2, and particularly preferably greater than or equal to 0.25. The profile thickness ratio is preferably at most 0.5, in particular 0.4 and particularly preferably 0.35. The pressure-side inlet angle is preferably between 30 ° and 90 °, more preferably between 35 ° and 80 °, and the inlet-side inlet angle between 25 ° and 80 °, particularly preferably between 30 ° and 60 °, the pressure-side outlet angle between 130 ° and 180 ° , more preferably between 150 ° and 170 °, and the suction-side exit angle between 120 ° and 170 °, more preferably between 140 ° and 160 °, particularly preferably in each case in the central region, ie in particular +/- 10 ° around the mean of the respective ranges given above, in order to achieve an optimal flow pattern without detachment as well as an optimal efficiency and a low-noise operation.

The channel ratio, i. the ratio of the flow channel width at the inlet and the outlet, is preferably 0.4 to 0.8, particularly preferably 0.5 to 0.75 and particularly preferably 0.55 to 0.7.

The flow channel width A1 at the entrance, i. the diameter of a circle in the channel at the inlet, is, in particular in an impeller with the aforementioned preferred geometries, preferably about 6 mm.

The flow channel width A2 at the exit, i. the diameter of a circle in the channel at the outlet, is, in particular in an impeller with the aforementioned preferred geometries, preferably about 3.5 mm.

Preferably, the blades are formed by a supporting, preferably solid, structure, to which at least partially a soft component sprayed or in the at least partially a soft component is injected. This is preferably in the supporting structure to a first plastic, which has a sufficient strength, and the soft component to a second plastic, which is softer. The second plastic is preferably a foamed plastic. This embodiment allows a substantially distortion and shrinkage-free manufacture of the impeller.

The maximum wall thickness of the supporting structure in the region of the blades is preferably 3 mm. With such a restriction of the wall thickness, warping and shrinkage can be surely avoided, in addition, if the ratio of the thickness of the hub disc to the thickness of the wall thickness of the supporting structure is approximately equal to 1. However, by a suitable choice of material of the structure forming material sufficient strength of the impeller can be ensured. In addition, by an appropriate choice of material of the soft component, the weight of the impeller can be reduced, so that the blower is lighter overall. Furthermore, the soft component has an acoustically absorbing effect, so that the blower is somewhat quieter than corresponding blowers without a soft component.

The soft component preferably forms at least in certain areas the profile of the blade, in particular in the strongly profiled part. Particularly preferably, a soft component layer is provided both on the suction and the pressure side, the ends of the blades are preferably soft component-free, whereby the soft component is additionally protected against damage during assembly.

According to a weight-saving embodiment, the blades are preferably at least partially formed as a hollow profile. In this case, webs may be formed in the hollow profiles to increase the rigidity. These are preferably closed on one side. In the case of a frame-side closure the hollow sections, the blades are preferably tapered conically tapered side.

The blades are preferably formed on the impeller hub side of the motor side cylindrical and the frame side conical, wherein they taper in the frame direction. This ensures that, despite the strong profiling in connection with the overlap by the frame, a sufficient intake cross-section is available and there is no obstruction of the Ansaugquerschnitts.

The production of such an impeller is preferably carried out by means of plastic injection molding, preferably first a load-bearing structure of a first plastic injection molded and then or almost simultaneously at least a portion of profiled trained blades of the impeller and / or a hollow profile is injection-molded by a second, softer plastic which is applied to the supporting structure or injected into a hollow profile formed by the supporting structure.

Suitable materials for the supporting structure are in particular PA or PP, but also metals. The soft component surrounding the supporting structure, at least in some areas, is preferably in the form of a foamed plastic, in particular S-EPS. Also very suitable is PP-EPDM. In general, PUR foam, melamine foam, PE foam (use of propellant in the application), silicone foam or, with limitations, foamed elastomers can be used.

The materials mentioned for the supporting structure can also be used accordingly for wheels without soft component.

Fig. 1

eine perspektivische Ansicht eines erfindungsgemäßen Laufrads gemäß dem Ausführungsbeispiel,

Fig. 2

eine Draufsicht auf mehrere nebeneinander angeordnete Schaufeln des Laufrads von Fig. 1 ohne Stützring,

Fig. 3

eine Darstellung der Strömungsgeschwindigkeiten in einem herkömmlichen Laufrad (links) und im Laufrad von Fig. 1 (rechts),

Fig. 4

einen schematisch dargestellten Schnitt in Längsrichtung durch eine Schaufel zur Verdeutlichung der Schaufelverjüngung,

Fig. 5

einen ausschnittsweisen Schnitt quer durch ein Laufrad mit verjüngten Schaufeln,

Fig. 6

einen Fig. 5 entsprechenden Schnitt zur Verdeutlichung der Verringerung der Schaufelquerschnittsfläche,

Fig. 7a-7d

schematische Darstellungen möglicher Verläufe von Schaufelverjüngungen,

Fig. 8

eine schematische Darstellung einer symmetrischen Verjüngung relativ zur Basisprofilskelettlinie der Schaufel,

Fig. 9

eine schematische Darstellung einer asymmetrischen Verjüngung relativ zur Basisprofilskelettlinie der Schaufel, und

Fig. 10

eine schematische Darstellung einer symmetrisch-asymmetrischen Verjüngung relativ zur Basisprofilskelettlinie der Schaufel.

In the following the invention will be explained with reference to an embodiment with several variants with reference to the drawings in detail. In the drawing show:

Fig. 1

a perspective view of an impeller according to the invention according to the embodiment,

Fig. 2

a plan view of a plurality of juxtaposed blades of the impeller of FIG. 1 without support ring,

Fig. 3

a representation of the flow velocities in a conventional impeller (left) and in the impeller of Fig. 1 (right),

Fig. 4

a schematic longitudinal section through a blade to illustrate the blade taper,

Fig. 5

a sectional section across a wheel with tapered blades,

Fig. 6

5 a section corresponding to FIG. 5 to illustrate the reduction in the blade cross-sectional area,

Fig. 7a-7d

schematic representations of possible courses of blade tapering,

Fig. 8

a schematic representation of a symmetrical taper relative to the base profile skeleton line of the blade,

Fig. 9

a schematic representation of an asymmetrical taper relative to the base profile skeleton line of the blade, and

Fig. 10

a schematic representation of a symmetrical-asymmetrical taper relative to the base profile skeleton line of the blade.

A tumbler radial fan, which is used for the promotion of air in an automotive air conditioning system, typically has an impeller 1 with a ring of blades 2, wherein between each two blades 2, a blade channel 3 is formed. The impeller 1 is mounted on a fan motor shaft (not shown) in a known manner. On the suction side, the impeller 1 is partially covered by the frame, which is part of the spiral housing.

The blades 2 have a profiled shape, the flow channel 3 being convergent in the inlet region 4 and in the outlet region 5 (see FIG. 2). The pressure side DS of the blades 2 is concave in the inlet region 4, optionally to the outlet region 5, and the suction side SS of the blades 2 is convex in the inlet region 4 and in the outlet region 5, wherein the blade thickness d is usually at its maximum between the blade center and the inlet area 4 has.

According to the present variant shown in the drawing, the blades have a solid cross-section and are made of a single material, for example a light metal or a plastic, which may also be foamed. By the double line used in Figure 2 for the representation of the blades a Ausformschräge is to be indicated. On the representation of the support ring 9 has been omitted in Figure 2.

In order to avoid problems in the production of highly profiled blades, the blades 2 are made according to a variant not shown in the figures of a structure which is formed as a kind of hollow profile. In this case, the thickness of the structure is a maximum of 3 mm, so that no problems with regard to distortion or shrinkage occur in the production of the structure, if in addition the hub disc thickness 6 is a maximum of 3 mm. In addition, this thickness usually suffices for sufficient rigidity of the blades 2. The supporting structure consists of PA or PP.

According to another variant, not shown in the figures, in order to avoid the problems mentioned in the production of highly profiled blades, the blades 2 are made of a structure which is solidly made of a plastic and have sufficient strength for the expected loads, and a molded on the structure layer of a soft component, which forms the profile in the strongly profiled region of the blade. In this case, the thickness of the structure is a maximum of 3 mm, so that no problems with regard to distortion or shrinkage occur in the production of the structure, if in addition the hub disc thickness 6 is a maximum of 3 mm. In addition, this thickness usually suffices for sufficient rigidity of the blade. The sprayed-on layer serves only for profiling and, apart from the requirement not to be compressed by the air to be conveyed, has no supporting function. In this case, the sprayed layer may also have a skin or a coating on its outer side, wherein the coating, in particular to avoid contamination, may also cover the entire blades or the entire impeller in order to simplify the production. In this case, the supporting structure is slightly tapered in the region of the blade covered by the soft component, wherein the taper takes place gradually. The outer contour is not affected by the transition from supporting structure to soft component.

The supporting structure according to the present embodiment consists of PA, the soft component of PP-EPDM.

According to a further variant of the blade, a web or other stiffening elements, such as ribs, may be provided in the hollow profile. In addition, soft components can be injected or injected. Also in this case, the thickness of the structure is at most 3 mm, so that no distortion or shrinkage occurs during manufacture.

By means of the position of the load-bearing structure within the profile, the thickness of the soft component on the blade suction and pressure sides can be adjusted such that only minimal, non-flow-influencing deformation of the soft component, in particular on the blade pressure side, occurs during blower operation.

Furthermore, in such a profiled blade design, as shown in Fig. 3, right part is clearly visible, no vortex formation on the suction side of the blade 2, so that the flow is good. This leads to an improvement of the efficiency eta in the CFD calculation. (See illustration in Fig. 3, wherein in each case the flow profile and the corresponding efficiency at the optimum operating point of the corresponding blower is shown).

• Das Profildickenverhältnis d/Lges liegt bevorzugt zwischen 0,15 und 0,5, insbesondere zwischen 0,2 und 0,4, insbesondere bevorzugt zwischen 0,25 bis 0,35, wobei d die Profildicke und Lges die Proflgesamtlänge (gerade gemessen) bezeichnen:
• Das Kanallängenverhältnis Lkv liegt bevorzugt zwischen 0,5 und 0,95, insbesondere zwischen 0,6 bis 0,9, insbesondere bevorzugt zwischen 0,70 bis 0,85. Dabei bezeichnet Lges die Länge des gesamten, Lgekr die Länge des gekrümmten Schaufelkanals. Das Kanallängenverhältnis Lkv ergibt sich aus: $$\mathrm{L}\mathrm{k}\mathrm{v}=\mathrm{L}\mathrm{g}\mathrm{e}\mathrm{k}\mathrm{r}/\mathrm{L}\mathrm{g}\mathrm{e}\mathrm{s}.$$
  

The following geometries are particularly suitable for a convergent blade channel, in particular for heavily profiled blades:

• The profile thickness ratio d / Lges is preferably between 0.15 and 0.5, in particular between 0.2 and 0.4, particularly preferably between 0.25 and 0.35, where d denotes the profile thickness and Lges the total profiled length (measured just) :
• The channel length ratio Lkv is preferably between 0.5 and 0.95, in particular between 0.6 and 0.9, particularly preferably between 0.70 and 0.85. Lges denotes the length of the entire, Lgekr the length of the curved blade channel. The channel length ratio Lkv results from: $$\mathrm{L}\mathrm{k}\mathrm{v}=\mathrm{L}\mathrm{G}\mathrm{e}\mathrm{k}\mathrm{r}/\mathrm{L}\mathrm{G}\mathrm{e}\mathrm{s},$$
  

The channel viewing ratio Ksv is preferably between 0.7 and 0.95, in particular between 0.75 and 0.95 and particularly preferred between 0.80 and 0.95. The channel chord ratio Ksv results from: $$\mathrm{K}\mathrm{s}\mathrm{v}=\mathrm{K}\mathrm{s}/\mathrm{L}\mathrm{G}\mathrm{e}\mathrm{k}\mathrm{r},$$

Here, Ks denotes the length of the channel chord.

The channel bulge ratio Kwv is preferably between 0.1 and 0.5, in particular between 0.15 and 0.4 and particularly preferably between 0.2 and 0.3. The channel vault ratio is given by: $$\mathrm{K}\mathrm{w}\mathrm{v}=\mathrm{K}\mathrm{w}/\mathrm{K}\mathrm{s},$$

Kw refers to the channel arch.

The channel bulge retention ratio Kwrv is preferably between 0.3 and 0.5, in particular between 0.35 and 0.45 and particularly preferably between 0.4 and 0.45. The channel vault reserve ratio is given by: $$\mathrm{K}\mathrm{w}\mathrm{r}\mathrm{v}=\mathrm{K}\mathrm{w}\mathrm{r}/\mathrm{K}\mathrm{s},$$

Kwr designates the channel bulge reserve.

Here, the impeller 1, the pressure-side inlet angle beta1DS between 30 ° and 90 °, preferably between 35 ° and 80 °, and the suction-side entrance angle beta1SS between 25 ° and 80 °, preferably between 30 ° and 60 °. The pressure-side outlet angle beta2DS between 130 ° and 180 °, preferably between 150 ° and 170 °, and the suction-side outlet angle beta2SS between 120 ° and 170 °, preferably between 120 ° and 160 °.

As a result of a strongly profiled design of the blades 2 in conjunction with the inlet opening (only about 1/3 of the blading are generally not covered by the frame) may occur at high mass flows to obstructions in the inlet area. These can lead to a reduction in the efficiency and / or acoustic disadvantages. For this reason, according to a further variant, the blades 2 are formed over their length or at least one or more parts thereof parallel to the axis of rotation with a different cross section. In this case, the cross section is on the inlet side, impeller-hub side cylindrical with a Ausformschräge and the frame side conically tapered in the longitudinal direction of the frame towards tapered.

FIGS. 4 to 6 show a variant with blades 2 tapering in the direction of the inflow side. In this case, the blades have a constant cross section over a large part of the blade length in the direction of the axis of rotation. Only in the last quarter, the cross-section of the blades decreases and both in the longitudinal profile direction, wherein the inner diameter dinenn enlarged up to a tapered inner diameter diverj, the outer diameter but there remains constant, as well as in the thickness direction. For a better clarification of the profile change, the skeleton line of the base profile is indicated in FIG. 5 by a dash-and-dash line. The course of the taper over the entire blade length is shown in FIG. 4. The total blade length is hereby designated Slgesamt, the portion of the blade length in which the inner diameter is increased is denoted by Slverj. The inner diameter diverj hereby increases, as can be seen in FIG. 4, in the last quarter of the blade length. The representation of Fig. 4 with respect to the profile length is not to scale.

In general, ratios of blade length tapered to total blade length (slver / total) are from 0.1 to 0.7, preferably from 0.15 to 0.5, and more preferably from 0.20 to 0.25.

beträgt in der Regel 0,01 bis 0,2, vorzugsweise 0,02 bis 0,1 und insbesondere bevorzugt 0,04 bis 0,07, wobei sich Dnenn und Dverjüngt ergeben aus $$\mathrm{D}\mathrm{nenn}=\mathrm{d}\mathrm{i}\mathrm{nenn}/\mathrm{d}\mathrm{a}$$

und $$\mathrm{D}\mathrm{verjüngt}=\mathrm{d}\mathrm{i}\mathrm{verj}/\mathrm{d}\mathrm{a}$$

The diameter ratio DV resulting from the following equation $$\mathrm{D}\mathrm{V}=\left(\mathrm{D}\mathrm{call}-\mathrm{D}\mathrm{rejuvenated}\right)/\mathrm{D}\mathrm{call}$$

is usually 0.01 to 0.2, preferably 0.02 to 0.1 and particularly preferably 0.04 to 0.07, wherein Dnenn and D tapered result from $$\mathrm{D}\mathrm{call}=\mathrm{d}\mathrm{i}\mathrm{call}/\mathrm{d}\mathrm{a}$$

and $$\mathrm{D}\mathrm{rejuvenated}=\mathrm{d}\mathrm{i}\mathrm{rejuvenation}/\mathrm{d}\mathrm{a}$$

Here, there is the blade outer diameter, dinenn the nominal inner diameter of the blades and diverj the tapered inner diameter of the blades.

wobei Anenn die Querschnittsfläche im nicht verjüngten Bereich ist, und im Folgenden auch als Basisprofil bezeichnet wird, und Averj die Querschnittsfläche im (am meisten) verjüngten Bereich ist. Die Veränderung des Schaufelprofils ist besonders gut aus Fig. 6 ersichtlich. Im Allgemeinen, d.h. nicht explizit auf die vorliegende Variante bezogen, liegt die relative Querschnittsflächenabnahme AV im Bereich von 0,1 bis 0,90, insbesondere von 0,2 bis 0,8 und besonders bevorzugt von 0,3 bis 0,7.In addition to the blade profile length, the thickness of the blade profile is also reduced, so that the cross-sectional area of the blade profile also decreases in the tapered region. The relative cross-sectional area decrease results $$\mathrm{A}\mathrm{V}=\left(\mathrm{A}\mathrm{call}-\mathrm{A}\mathrm{rejuvenation}\right)/\mathrm{A}\mathrm{call}$$

where Anenn is the cross-sectional area in the non-tapered area, hereinafter also referred to as base profile, and Averj is the cross-sectional area in the (most) tapered area. The change of the blade profile is particularly well from Fig. 6 can be seen. In general, ie, not explicitly related to the present variant, the relative cross-sectional area decrease ΔV is in the range from 0.1 to 0.90, in particular from 0.2 to 0.8 and particularly preferably from 0.3 to 0.7.

Further variants with regard to the progression of the taper are shown by way of example in FIGS. 7a to 7d, FIG. 7a showing a convex taper, FIG. 7b a concave taper, FIG. 7c a linear taper, and FIG. 7d a simple graduated taper. Any combination as well as a possibly multi-graded rejuvenation course are possible.

Figures 8 to 10 show variants with respect to the shape of the taper of the blade profile in the direction of the inflow side. The course of the taper can, for example, take place in accordance with the representation of FIGS. 7a to 7d. To better illustrate the change in profile, the skeleton line of the respective base profile is indicated by a star-dashed line in Figures 8 to 10.

The taper relative to the base profile can be made symmetrical to the skeleton line, as shown in Fig. 8 by the dashed line in a blade 2 on the suction side. The taper relative to the base profile can also be asymmetric to the skeleton line, as shown in Fig. 9 in a blade 2 by the dotted line on the suction side. The rejuvenation can also be symmetrical in some areas and asymmetric in certain areas Skeleton line, as shown in Figures 8 to 10 in solid lines and is apparent in comparison of the solid lines with respect to the dashed or dotted line.

It should generally be noted that the channel shape in the tapered part of the blading can be designed to be both convergent, as provided according to the invention, and convergent-divergent or divergent.

Particularly preferably, the entry and exit angles in the tapered blade part deviate from those in the region of the base profile, i. in the part with a constant cross section, from which results in an aerodynamic distortion of the blade profile. However, the angles may also remain constant or at least substantially constant.

According to another variant, also not shown in the drawing, the blades are formed by hollow profiles, which are made of a single material. It can also be provided for stiffening the profile and transverse struts, so that in particular a plurality of separate cavities can be formed.

If the blades are designed as (partial) hollow profiles, then they may be open or closed on the frame side.

Claims (19)

Impeller, in particular plastic impeller for a drum rotor radial fan for the heating and air conditioning of a motor vehicle, comprising a plurality of blades (2), characterized in that the flow channel (3) between two blades (2) is substantially convergent in the flow direction and the impeller blades are formed strongly profiled. Impeller according to claim 1, characterized in that the ratio of the profile thickness (d) to the overall profile length (Lges) of the blade (2) is greater than or equal to 0.15, in particular greater than or equal to 0.2 and particularly preferably greater than or equal to 0.25 , Impeller according to claim 1 or 2, characterized in that the channel ratio (A2 / A1) is 0.4 to 0.8, in particular 0.5 to 0.75 and particularly preferably 0.55 to 0.7. Impeller according to one of the preceding claims, characterized in that the channel length ratio (Lkv) is between 0.5 and 0.95, in particular 0.6 to 0.9, particularly preferably 0.70 to 0.85. Impeller according to one of the preceding claims, characterized in that the channel chord ratio (Ksv) is between 0.7 and 0.95, especially between 0.75 and 0.95, and more preferably between 0.80 and 0.95 Impeller according to one of the preceding claims, characterized in that the channel bulge ratio (Kwv) is between 0.1 and 0.5, in particular between 0.15 and 0.4 and particularly preferably between 0.2 and 0.3 Impeller according to one of the preceding claims, characterized in that the blades (2) are profiled so that the pressure-side inlet angle (beta1 DS) between 30 ° and 90 °, in particular between 35 ° and 80 °, and the suction-side inlet angle (beta1SS) between 25 ° and 80 °, in particular between 30 ° and 60 °, the pressure-side outlet angle (beta2DS) between 130 ° and 180 °, in particular between 150 ° and 170 °, and the suction-side outlet angle (beta2SS) between 120 ° and 170 °, in particular between 140 ° and 160 °. Impeller according to one of the preceding claims, characterized in that the impeller has a hub disc (6) whose maximum solid wall thickness is at most 3 mm. Impeller according to one of the preceding claims, characterized in that on a supporting structure of the blade (2) at least partially sprayed on a soft component or in the at least partially injected a soft component. Impeller according to claim 9, characterized in that the maximum solid wall thickness of the supporting structure in the region of the blades is 3 mm. Impeller according to claim 9 or 10, characterized in that the ratio of the maximum wall thickness of the supporting structure in the region of the blades to the hub disc thickness is equal to 1. Impeller according to one of claims 9 to 11, characterized in that the soft component at least partially forms the profile of the blade (2). Impeller according to one of the preceding claims, characterized in that the blades are at least partially formed as a hollow profile. Impeller according to one of the preceding claims, characterized in that the blades are hollow, wherein webs are provided in the hollow blades. Impeller according to claim 13 or 14, characterized in that the blades designed as a hollow profile are closed on one side. Impeller according to one of claims 13 to 15, characterized in that in the interior of the hollow profile, a soft component is injected. Impeller according to one of the preceding claims, characterized in that the impeller (1) is produced by means of two-component plastic injection molding. Impeller according to one of the preceding claims, characterized in that the blade profile tapers at least partially in the direction of the frame. Impeller according to one of the preceding claims, characterized in that the blades (2) are cylindrical and zargenseitig conically on the impeller hub side.

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