Motor-vehicle fan wheel with reinforced shroud

Abstract

A fan of a motor vehicle is particularly suited as a main fan of an internal combustion engine. The fan has a fan wheel with an outer ring which has a substantially L-shaped ring cross section. The L-shape is defined with a radial limb and an axial limb. The radial limb has a cross-sectional enlargement on a free-end side.

Claims

1. A fan of a motor vehicle, comprising: a fan wheel with an outer ring and a hub defining a rotational axis; said fan wheel defining a radial direction and an axial direction; said outer ring having a substantially L-shaped annular cross section, formed by a radial limb with a standard cross section and a cross-sectional enlargement at a free end thereof and by an axial limb, said outer ring, in a transitional region between said radial limb and said axial limb, being formed with an annular cross-sectional reduction of said radial limb being annular about said hub and said rotational axis, said cross-sectional reduction being radially inward of said standard cross section and said standard cross section being greater than said cross-sectional reduction.

2. The fan according to claim 1, configured as a main fan of an internal combustion engine.

3. The fan according to claim 1, wherein said cross-sectional enlargement is formed substantially circumferentially along a periphery of said radial limb.

4. The fan according to claim 1, wherein the limb portion with the standard cross section extends between said cross-sectional reduction and said cross-sectional enlargement.

5. The fan according to claim 1, which comprises a shroud with a shroud ring having said radial limb at least partially incorporated therein, and wherein said radial limb is disposed along an airflow produced by the fan and substantially upstream of said axial limb.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 is a perspective view of a fan wheel with an outer ring;

(2) FIG. 2 is a perspective of a detail of an alternative embodiment of the L-shaped outer ring;

(3) FIG. 3 is a sectional view of the fan wheel within a shroud; and

(4) FIG. 4 shows a detail IV of FIG. 3 in a larger scale, with the outer ring partially incorporated in a shroud ring.

DETAILED DESCRIPTION OF THE INVENTION

(5) Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown a fan wheel 2 in a perspective view. The fan wheel is produced integrally in one piece from a plastics material, in particular from polyamide. The fan wheel 2 is heated to a relatively high temperature during the production thereof. For example, the fan wheel 2 is pressed, cast or produced in an injection-molding process. A number of fan blades 6 are arranged around a central hub 4. An electric motor 8 (cf. FIG. 3) may be attached to the hub 4. That is, the electric motor 8 is operatively connected to the fan wheel 2. The fan blades 6 in each case are provided so that with a rotational movement of the fan wheel 2 around the hub 4 along a rotational axis x an airflow is produced by way of the electric motor 8 along the rotational axis x. The fan blades 6 are surrounded by an outer ring 10 which, among other things, serves for stabilizing the fan blades 6 during the rotational movement. By way of the outer ring 10, the airflow is guided and the aerodynamic properties of the fan wheel 2 are improved.

(6) The outer ring 10 has an L-shaped cross section with a radial limb 12 and an axial limb 14. The axial limb 12 is parallel to the rotational axis x and is connected to the fan blades 6. The radial limb 14 is orthogonal (at right angles) to the axial limb 12 and extends from the hub 4 located in the center of the fan wheel 2, outwardly in a radial direction y. In this case, the distance of the radial limb 14 from the hub 4 is substantially greater than that of the axial limb 12. At the free end, the radial limb has a cross-sectional enlargement 16 in the form of a bent-back portion. The cross-sectional enlargement 16 is designed to be entirely peripheral. In other words, the cross-sectional enlargement 16 would produce a closed ring if said ring were to be detached from the radial limb 14. By means of the cross-sectional enlargement 16, the outer edge of the axial limb 12 is stabilized so that with a rotational movement of the fan wheel 2 no vibrations or only relatively weak vibrations of the radial limb 14 are produced. Moreover, during the rotational movement of the fan wheel 2 the radial limb 14 is bent to a relatively small degree in the direction of the rotational axis x. In the region of a transition 18 between the radial limb 14 and the axial limb 12, the outer ring 10 has a cross-sectional reduction 20 in the form of a bead. When cooling the fan wheel 2, said fan wheel tends to deform. By means of the cross-sectional reduction 20, this deformation is counteracted so that the angle between the axial limb 12 and the radial limb 14 during cooling remains constant and thus after cooling corresponds to the angle during the production of the fan wheel 2. A portion of the radial limb 14 which has a normal or standard cross section 22 is located between the cross-sectional reduction 20 and the cross-sectional enlargement 16.

(7) FIG. 2 shows in detail a perspective view of an alternative embodiment of the outer ring 10, wherein the outer ring 10 is in section along a plane along the rotational axis x. The cross-sectional reduction 20 in turn has a substantially rectangular cross section and is entirely incorporated in the radial limb 14. Conversely, the cross section of the axial limb 12 is substantially uniform. The outer edge is rounded in the region of the transition 18 between the radial limb 14 and the axial limb 12.

(8) The region of the radial limb 14 which has the normal cross section 22 extends directly adjacent to the cross-sectional reduction 20. Said normal cross section is substantially the same as the cross section of the axial limb 12. In contrast to the cross-sectional enlargement 16 shown in FIG. 1, the cross-sectional enlargement 16 shown in FIG. 2 is not peripheral. The cross-sectional enlargement 16 is instead located at specific regions of the radial limb 14 along the periphery of the outer ring 10. In this manner, the cross-sectional enlargement 16 forms a number of teeth 24, the respective spacing thereof to one another as shown here, being able to vary or also be constant. Similarly, a variation is possible in the length of the teeth 24 along the periphery or in the radial direction. In this manner, for example, imbalance of the fan wheel 2 may be corrected or specifically produced.

(9) Both the cross-sectional reduction 20 and the cross-sectional enlargement 16 are located on the side of the radial limb 14 facing the axial limb 12. In this manner, a planar surface is produced on the side of the radial limb 14 which is remote from the axial limb 12.

(10) FIG. 3 shows in a sectional view in detail the fan wheel 2 along the cutting plane described in FIG. 2. FIG. 4 shows an enlarged detail of FIG. 3. For example, in this case the cross-sectional enlargement 16—comparable with the cross-sectional enlargement 16 shown in FIG. 1—is entirely peripheral. Also shown is a shroud ring 26 of a shroud 28 with a shroud body 30. The shroud ring 26 in this case indicates an indentation within the shroud body 30 which extends in an annular manner around a recess 32 within the shroud body 30, wherein the fan blades 6 are located within the recess 32. The radial limb 14 is incorporated partially within the shroud ring 26, wherein the planar side of the radial limb 14 is substantially parallel to the surface of the shroud body 30 and is located in a plane which extends in the radial direction y, wherein the rotational axis x is located perpendicular to said plane. The airflow produced by means of the fan wheel 2 is deflected by means of the shroud 28 through the recess 32, wherein the radial limb 14 is located along the airflow upstream of the axial limb 12. Due to the relatively high degree of stability of the radial limb 14, as a result of the cross-sectional enlargement 16, a relatively small spacing may be selected between the shroud 28 and the fan wheel 2, without the fan wheel coming into contact with the shroud 28, with a rotational movement of said fan wheel 2. In this manner, the airflow is deflected relatively effectively through the shroud 28 and relatively low losses in the form of so-called leaking air are produced in the edge region of the fan wheel 2.

(11) In a manner not shown in more detail, both the shroud 28 and the electric motor 8 and the fan wheel 2 are a component of a fan 34 of a motor vehicle with an internal combustion engine, which drives the motor vehicle directly, for example via a gear mechanism, or indirectly in the manner of a so-called hybrid drive. By way of the fan 34, the internal combustion engine is cooled directly or indirectly. The indirect cooling takes place by the internal combustion engine being cooled by means of a coolant which in turn is in heat exchange with a conventional cooler for cooling purposes. The fan 34 and specifically the shroud 28 is attached to the cooler. The airflow generated by means of the fan 34 flows through the cooler and thus cools said cooler.

(12) The invention is not limited to the exemplary embodiments described above. On the contrary, other variants of the invention may be derived therefrom by the person skilled in the art without departing from the subject-matter of the invention. In particular, all of the individual features described in connection with the exemplary embodiments are also able to be combined with one another in different ways without departing from the subject-matter of the invention.