Rotor disk

Abstract

An impeller (1), in particular a radial-flow fan or compressor impeller is proposed for an internal combustion engine. This impeller has an unequal number of full blades and split blades (4, 5) arranged at a different angular distance and in a different order. This further reduces the noise produced.

Description

[0001] This application is the U.S. National Stage application of PCT/EP02/04920, filed May 4, 2002, which claims the priority of German Patent Application No. 101 22 516.4, filed May 9, 2001, the disclosures of which are expressly incorporated by reference herein.

[0002] The present invention relates generally to an impeller, in particular a radial-flow fan or a compressor impeller having a different number of full blades and split blades.

[0003] In internal combustion engines, impellers are used, e.g., as radial-flow fans or as compressor impellers for an exhaust gas turbocharger. One problem with these impellers is the generated noise, which is often perceived as unpleasant. One measure commonly used for noise reduction consists of equipping the impeller with full blades and split blades. Such an embodiment is known from European Patent 0 439 267 B1. In addition, the number of full blades on this impeller may be different from the number of split blades.

SUMMARY OF THE INVENTION

[0004] An object of the present invention is to further reduce the noise emission by an impeller.

[0005] This object is has been achieved by arranging the full blades and the split blades at a different angular distance and in a different order.

[0006] The present invention thereby greatly reduces the noise level. Due to these measures, the acoustic power is distributed among several individual tones, the intensity of which turns out to be accordingly lower. Another advantage is that the efficiency and power consumption of the impeller remain almost constant. Due to the use of an alternative material, e.g., aluminum, the mass moment of inertia of the impeller is reduced. In actual practice, this means that a much better response characteristic is achieved in an impeller having a diameter of, for example, 670 mm.

[0007] Through appropriate shaping of the rear side of the impeller, a coupling and a bearing can be integrated. This yields the advantage that the component density is increased while the overall height remains the same. As a consequence, this results in a configuration that is easier to install.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] These and other objects, features and advantages of the present invention will become more readily apparent from the following detailed description of currently preferred configurations thereof when taken in conjunction with the accompanying drawings wherein:

[0009] FIG. 1 is a perspective view of an impeller in accordance with the present invention;

[0010] FIG. 2 is a sectional top view of the impeller of FIG. 1;

[0011] FIG. 3 is a sectional side view of the impeller of FIG. 1; and

[0012] FIG. 4 is a side sectional view of an impeller having an integrated coupling.

DETAILED DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 shows an impeller 1, in particular a radial-flow fan or compressor impeller. It consists of a cover plate 2, a base plate 3, a hub 6 with a mounting hole 7 and blades. The blades of the impeller 1 are configured as full blades 4 and split blades 5. The geometry of the full blades is not identical to that of the split blades here because the split blades form part of the full blades. The full blades 4 and split blades 5 are arranged at a different angular distance and in a different order, the arrangement and order of which can be seen from the sectional diagram in FIG. 2. For example, the split blade 5.1 is followed by a full blade 4.1, then a split blade 5.2, followed by four full blades 4.2 to 4.5 and a split blade 5.3. The noise generated is further reduced due to the different angular distance and the different order while achieving almost the same efficiency and/or power consumption. The level and frequency of the noise, which is perceived as unpleasant, are reduced by these measures and distributed over a broader frequency band. Due to these structural measures, the acoustic power is distributed among several individual tones, the intensity of which turns out to be accordingly lower.

[0014] The impeller 1 is preferably made of an alternative material, e.g., aluminum. This results in a significant reduction in the mass moment of inertia. The impeller 1 shown in FIG. 1 also has balancing holes 8. An imbalance in the impeller 1 is compensated by these balancing holes 8. This reduces manufacturing costs because it is no longer necessary to mount additional balancing weights.

[0015] FIG. 2 shows a first area 15 and a second area 16. Only full blades 4 are arranged in the first area 15. Both full blades and split blades are arranged in the second area 16. The order of the full blades 4.1 through 4.6 and the split blades 5.1 through 5.4 is irregular in the second area 16. The angles between two blades on the air intake side and the air outlet side are identical. The angle x1 between the split blade 5.1 and the full blade 4.1 thus corresponds to the angle x2. The angle y1 between the full blade 4.1 and the split blade 5.2 corresponds to the angle y2. The same is also true of the angles z1 and z2. However, these angles are different from one another, i.e., x1 is not equal to y1 and is not equal to z1. On the whole, the order of the full blades 4 and the split blades 5 is not rotationally symmetrical, not even in segments.

[0016] FIG. 3 shows the impeller 1 in a side view. The direction of flow of the air is indicated with arrows. As shown here, the air is conveyed by the impeller 1 in the axial direction, i.e., radially outward, from above in the direction of the drawing. In addition, FIG. 3 shows the arrangement of the full blades and the split blades between the cover plate 2 and the base plate 3.

[0017] FIG. 4 shows the impeller 1 with an integrated coupling and a coupling housing 9. The coupling housing 9 is integrated into the impeller 1 on the rear side 13. This arrangement provides the advantage that a greater component density is achieved with the same overall height of the impeller. Reference numeral 10 denotes the connection for a housing, e.g., a gear box. The impeller 1 is detachably connected to a wheel mount 11 by a screw 14 from the front side 12. The wheel mount 11 is in turn fixedly connected to the coupling and the coupling housing 9. The impeller 1 is activated or deactivated on the basis of the status of the coupling 9.

[0018] Although the present invention has been illustrated and described with respect to exemplary embodiment thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omission and additions may be made therein and thereto, without departing from the spirit and scope of the present invention. Therefore, the present invention should not be understood as limited to the specific embodiment set out above but to include all possible embodiments which can be embodied within a scope encompassed and equivalent thereof with respect to the feature set out in the appended claims.

Claims

1. Impeller for a radial-flow fan or compressor impeller, comprising full blades and split blades different in number from the full blade, wherein the full blades and the split blades are arranged at a different angular distance and in a different order.

2. Impeller as claimed in claim 1, further comprising a coupling and a bearing integrated on a rear side of the impeller.

3. Impeller as claimed in claim 2, wherein the impeller is made of a material selected to minimize mass moment of inertia.

4. Impeller as claimed in claim 3, wherein balancing holes are arranged on the impeller to compensate for an imbalance in the fan wheel.

5. Impeller as claimed in claim 4, wherein the balancing holes are arranged on at least one of a cover plate and a base plate.

6. Impeller as claimed in claim 1, wherein the impeller is made of a material selected to minimize mass moment of inertia.

7. Impeller as claimed in claim 1, wherein balancing holes are arranged on the impeller to compensate for an imbalance in the fan wheel.

8. Impeller as claimed in claim 7, wherein the balancing holes are arranged on at least one of a cover plate and a base plate.