IMPELLER OF A MOTOR VEHICLE

Abstract

An impeller of a motor vehicle, in particular a cooling fan, comprising a hub, to which a number of fan blades are connected. The fan blades are inclined in relation to a rotational axis of the impeller and have in each case a section which in the top view is S-shaped along the rotational axis.

Claims

1. An impeller for use in a motor vehicle, the impeller comprising: a hub; and a number of fan blades attached to the hub and inclined with respect to an axis of rotation of the impeller, the number of fan blades each including a section having an shape with respect to a plan view along the axis of rotation.

2. The impeller of claim 1, wherein the impeller is configured to rotate about the axis of rotation in a preferential direction of rotation.

3. The impeller of claim 2, wherein radial outer ends of each of the number of fan blades are offset counter to the preferential direction of rotation.

4. The impeller of claim 2, wherein a trailing edge of each of the number of fan blades, with respect to the preferential direction of rotation, is undulated with respect to the preferential direction of rotation.

5. The impeller of claim 2, wherein a leading edge of each of the number of fan blades, with respect to the preferential direction of rotation, is straight with respect to a plan view counter to the preferential direction of rotation.

6. The impeller of claim 1, wherein each of the sections are outwardly offset from one another in a radial direction with respect to the axis of rotation.

7. The impeller of claim 1, wherein each of the number of fan blades are arranged in a rotationally symmetrical manner with respect to the hub.

8. The impeller of claim 1, wherein the number of fan blades includes a first fan blade and a second fan blade and a differential between an extent of the first fan blade and an extent of the second fan blade is less than 10%, wherein the extent of the first fan blade and the extent of the second fan blade are formed with respect to a tangential direction of the first and second fan blades.

9. The impeller as claimed in claim 1, further comprising: an outer ring arranged concentrically with the hub, wherein each of the fan blades of the number of fan blades include a radial outer end attached to the outer ring.

10. A radiator fan or use in a motor vehicle, the radiator fan comprising: a fan frame forming a round aperture; an electric motor; and an impeller including, a hub, and a number of fan blades attached to the hub and inclined with respect to an axis of rotation of the impeller, the number of fan blades each including a section having an s-shape with respect to a plan view along the axis of rotation.

11. The impeller of claim 8, wherein the differential between the extent of the first blade and the extent of the second blade is less than 5%.

12. The radiator of claim 10, wherein the impeller is configured to rotate about the axis of rotation in a direction of rotation and radial outer ends of each of the number of fan blades are offset counter to the preferential direction of rotation.

13. The radiator of claim 10, wherein a trailing edge of each of the number of fan blades, with respect to a direction of rotation, is undulated with respect to the preferential direction of rotation.

14. The radiator of claim 10, wherein a leading edge of each of the number of fan blades, with respect to a direction of rotation, is straight with respect to a plan view counter to the preferential direction of rotation.

15. The radiator of claim 10, wherein each of the sections are outwardly offset from one another in a radial direction with respect to the axis of rotation.

16. An impeller for use in a motor vehicle, the impeller comprising: a hub configured to rotate about a rotational axis in a first rotational direction; and a number of fan blades extending from the hub, each of the fan blades including, an inner end fixed to the hub, an outer end disposed radially outwardly from the inner end, and an S-shaped section extending between the inner end and the outer end, wherein the outer end leads the inner end with respect to the first rotational direction.

17. The impeller of claim 16, wherein a leading edge, with respect to the first rotational direction, of each of the number of fan blades extends perpendicularly to the rotational axis.

18. The impeller of claim 16, wherein each of the number of fan blades are arranged in a rotationally symmetrical manner with respect to the hub.

19. The impeller of claim 16, a trailing edge, with respect to the first rotational direction, of each of the number of fan blades has a sinusoidal wave shape.

20. The impeller of claim 16, further comprising: an outer ring arranged concentrically with the hub, wherein each outer end of the number of fan blades is attached to the outer ring.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Exemplary embodiments of the invention are explained in greater detail below with reference to the drawings. In the drawings:

[0030] FIG. 1 shows schematically a land-based motor vehicle with a radiator fan,

[0031] FIG. 2 shows a partial view of the radiator fan with an impeller in a schematically simplified form in an exploded view,

[0032] FIG. 3 shows the impeller in a plan view,

[0033] FIG. 4 shows a segment of the impeller in a plan view,

[0034] FIG. 5 corresponding to FIG. 4, shows an alternative embodiment of the impeller, and

[0035] FIG. 6 shows the impeller as per FIG. 5 in a plan view of a fan blade counter to a direction of rotation.

[0036] In all the figures, mutually corresponding parts are provided with the same reference signs.

DETAILED DESCRIPTION

[0037] As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0038] FIG. 1 schematically shows, in simplified form, a motor vehicle 2 with an internal combustion engine 4. The motor vehicle 2 is driven by means of the internal combustion engine 4. For this purpose, the internal combustion engine 4 is operatively connected to at least one of the four wheels 6 of the motor vehicle 2 by means of a drive train (not shown specifically). In addition, the motor vehicle 2 comprises a radiator fan 8, which is used to cool the internal combustion engine 4. Thus, the radiator fan 8 is a main fan of the motor vehicle 2. The radiator fan 8 is fluidically connected to the internal combustion engine 4 by means of a number of lines 10, through which, during operation, a cooling liquid is passed from the radiator fan 8 to the internal combustion engine 4 and through cooling ducts there. Excess heat is absorbed by means of the cooling liquid and returned to the radiator fan 8, by means of which the cooling liquid is cooled.

[0039] The radiator fan 8 has a radiator 12 with a radiator core (not shown specifically) through which a number of tubes is guided and thermally contacted therewith. The tubes are fluidically coupled to the lines 10, and therefore the cooling liquid is passed through the tubes during operation. The radiator fan 8 further comprises a fan frame 14, which is arranged behind the radiator 12 in a direction of travel 16 of the motor vehicle 2. An electric motor 18 is secured on the fan frame 14. During operation, a relative wind passes through the radiator 12 and is suitably shaped by means of the fan frame 14. When the motor vehicle 2 is at a standstill, air is sucked through the radiator 12 by means of the electric motor 18, ensuring that, during operation, the air flow passes through the radiator 12 essentially at all times or at least in accordance with existing requirements. Cooling of the radiator 12 thus takes place, for which reason there is no overheating of the radiator fan 8, even after comparatively prolonged operation of the internal combustion engine 4. In addition, the air passing through the radiator fan 8 is guided to the internal combustion engine 4 by means of the fan frame 14 and, in this way, the engine is additionally cooled from the outside.

[0040] FIG. 2 shows the radiator fan 8 in a schematically simplified form in perspective in an exploded view, the radiator 12 being omitted. Secured on the radiator 12 is the fan frame 14, which completely covers the radiator core (not shown specifically) and is congruent therewith. The fan frame 14 is of substantially planar design and has a round aperture 20, which is oriented perpendicularly to the direction of travel 16. The aperture 20 has a diameter of 30 cm and is surrounded at the circumference by a rim 22, which is of hollow-cylindrical configuration and is arranged concentrically with the aperture 20. The diameter of the rim 22 is equal to the diameter of the aperture 20, and the rim 24 has a length of 2 cm in the axial direction with respect to the aperture 22, that is to say parallel to the direction of travel 16. In the assembled state, the rim 22 is located on that side of the fan frame 14 which faces away from the radiator 12.

[0041] The fan frame 14 further comprises a motor mount 24, which is arranged above the aperture 20, counter to the direction of travel 16. In the assembled state, the electric motor 18 is held by means of the motor mount 24, and the electric motor 18 is thus secured on said mount. In this case, the electric motor 18 is located on the opposite side of the fan frame 14 from the radiator 12. A shaft 34 of the electric motor 18 projects through the motor mount 32 in the direction of travel 16 and is secured on a hub 26 of an impeller 28 for conjoint rotation therewith. Thus, the impeller 38 is driven by means of the electric motor 18, which is held by means of the motor mount 24. A number of fan blades 30 is attached to the hub 26, which fan blades are surrounded at the circumference by means of an outer ring 32 and are attached to the latter. The hub 26, the fan blades 30, and the outer ring 32 are produced in one piece in a plastic injection molding process.

[0042] In the assembled state, the impeller 28 is arranged within the aperture 22, parallel thereto, wherein the outer ring 32 is surrounded radially at the circumference by means of the rim 24. During operation, the impeller 38 is rotated by means of the electric motor 18 about an axis of rotation 34 which is parallel to the direction of travel 16 and which extends through the center of the aperture 20. Thus, during operation, air is sucked through the aperture 22 counter to the direction of travel 16. Between the outer ring 32 and the rim 24, a flow of air is prevented by virtue of a seal (not shown specifically), e.g. a labyrinth seal.

[0043] In addition, the fan frame 14 includes a dynamic pressure flap 36 that comprises an opening covered by a flap 38. If there is a comparatively high (air) pressure in front of the fan frame 14 in the direction of travel 16, for example in the case of a comparatively fast movement of the motor vehicle 2, passage of the air through the aperture 20 is partially impeded by the impeller 28 or the impeller 28 would have to be rotated comparatively quickly. However, this would lead to an increased load on the electric motor 18 and the further component and to increased noise generation. From a certain pressure, the flap 38 is therefore pivoted and the opening is exposed, thus allowing air to flow through it. Thus, an air throughput through the radiator 12, which is located in front of the fan frame 14 in the direction of travel 16, is increased. At a comparatively low air pressure in front of the fan frame 14, as is the case when the motor vehicle 2 is at a standstill, the flap 38 is closed, and therefore formation of a circular air flow passing only through the opening of the dynamic pressure flap 36 and the aperture 22 is prevented. Thus, there is also always a sufficient air flow through the radiator 12.

[0044] In FIG. 3, the impeller 28 is shown in a plan view along the axis of rotation 34, counter to the direction of travel 16. In FIG. 4, an enlarged segment of the impeller 28 is shown, corresponding to the illustration in FIG. 3. The hub 26 is of pot-shaped configuration, and the base of the hub 26 faces in the direction of travel 16. The fan blades 30 are attached to an outer wall of the hub 26. In the variant illustrated here, the impeller 28 has a total of nine such fan blades 30. The fan blades 30 are arranged in a rotationally symmetrical manner with respect to the hub 26, the axis of symmetry coinciding with the axis of rotation 34. In this case, the complete impeller 28 is rotationally symmetrical, the angle of symmetry corresponding to 40°.

[0045] The fan blades 30 are arranged between the outer ring 32 and the hub 26, in the radial direction with respect to the axis of rotation 34, the radially outer end 40 of the blades being connected to the outer ring 32. The outer ring 32 is arranged concentrically with respect to the hub 26 and consequently also with respect to the axis of rotation 34. The radially inner end 42 of each fan blade 30 is attached to the hub 26 and formed integrally thereon. In this arrangement, each fan blade 30 has a substantially radial course in the region of the two radial ends 40, 42.

[0046] Each fan blade 30 is inclined with respect to the axis of rotation 34 and is at an angle of between 80° and 60° with respect thereto, enabling comparatively efficient movement of the air along the axis of rotation 34 through the openings formed between the fan blades 30. Owing to the inclination of the fan blades 30, a preferential direction of rotation 43 is formed. When the impeller 28 rotates about the axis of rotation 34 in the preferential direction of rotation 43, air is sucked through the radiator 12 by means of the impeller 28. With a different direction of rotation, the air would move in the direction of travel 16 through the radiator 12. To improve efficiency, the fan blades 30 are furthermore of profiled configuration, and thus have an aerodynamic profile. Thus, an air throughput is increased. In summary, the impeller 28 has a preferential direction of rotation 43 about the axis of rotation 34.

[0047] Each fan blade 30 has a radially inner section 44, which is of substantially rectilinear radial or slightly C-shaped configuration in a plan view along the axis of rotation 34. The radially inner section 44 has the radially inner end 42 and merges into a section 46 of s-shaped configuration which has the radially outer end 40. Thus, the s-shaped sections 46 are offset outward in the respective radial direction with respect to the axis of rotation 34. On account of the s-shaped configuration of the section 46, the radial outer ends 40 of the fan blades 30 are offset counter to a preferential direction of rotation 48, the complete s-shaped section 46 being offset in each case in the preferential direction of rotation 43 with respect to the respective radially inner section 44.

[0048] In summary, the fan blades 30 are inclined with respect to the axis of rotation 34 and each have the section 46 which is s-shaped in a plan view along the axis of rotation 34. In this case, the extent of each fan blade 30 in the tangential direction, that is to say parallel to the preferential direction of rotation 43, does not change or changes only by less than 5% of the extent of the respective fan blade 30 in the tangential direction. In other words, each fan blade 30 has the same thickness in the tangential direction, that is to say along the preferential direction of rotation 43. Thus, comparatively efficient movement of the air is made possible.

[0049] As a result of the s-shaped section 46, the impeller 28 acts in the manner of a nozzle on the inflow side, that is to say on the side of the radiator 12, and acts in the manner of a diffuser on the outflow side, that is to say on the opposite side from the radiator 12. Thus, an additional radial motion component is introduced into the air flow generated or at least amplified by means of the impeller 28, and this component is thus directed away from the internal combustion engine 4. Thus, the air flow does not impinge at an obtuse angle on the internal combustion engine 4, which leads to reduced turbulence. Moreover, an area traversed by the air flow is increased on the downstream side, i.e. counter to the direction of travel 16, in comparison with the size of the aperture 20, and therefore a velocity of the air is reduced and consequently a pressure is increased. Consequently, an air volume throughput through the fan frame 14 and therefore also through the radiator 12 is increased at a constant rotational speed about the axis of rotation 34. Thus, efficiency is also increased. Alternatively, it is possible to rotate the impeller 28 at a lower rotational speed and thus to use a less powerful electric motor 18, which reduces production costs. Noise generation is also reduced. Moreover, separation of the air flow in the region of the outer ring 32 is reduced or avoided, which further increases efficiency.

[0050] FIG. 5, corresponding to the illustration in FIG. 4, shows a modification of the impeller 28, wherein the outer ring 32 and the hub 26 as well as the number of impellers 30 is unchanged. Here too, as in the previous example, each fan blade 30 has a leading edge 48 in the preferential direction of rotation 43. The leading edge 48 is likewise s-shaped in the region of the s-shaped section 46. The leading edge 48 is rounded over its entire length perpendicularly to its course, but is otherwise straight. In other words, the leading edge 48 does not extend in the axial direction, that is to say parallel to the axis of rotation 34. In summary, the leading edge 48 of the fan blades 30 with respect to the preferential direction of rotation 43 is straight in a plan view counter to the preferential direction of rotation 43.

[0051] In comparison with the preceding embodiment, however, the trailing edge 50 is no longer of straight configuration in a plan view in the preferential direction 34. On the contrary, the trailing edge 50 of the fan blades 30 with respect to the preferential direction of rotation 43 is undulating in a plan view in the preferential direction of rotation 34, as shown in FIG. 6. The trailing edge 50 thus has a wave shape, such as a sinusoidal course. In this case, both the radially inner section 44 and the s-shaped section 46 are undulating in the region of the trailing edge 50. The region between the two edges 48, 50 extends in a substantially continuous manner, but at least steadily, between the two edges 48, 50. As in the preceding example, the trailing edge 50 is offset with respect to the leading edge 48 owing to the inclination counter to the direction of travel 16, resulting in the preferential direction of rotation 43.

[0052] In summary, each of the fan blades 30, that is to say each blade airfoil, has the s-shaped section 46, which may be of boomerang-shaped configuration in the manner of a blade securing means. By means of this configuration, separation of the air flow from the outer ring 32 is prevented or at least reduced, such as if the radiator 12 is present. In addition, a radially outward motion component is introduced into the air flow passing through the impeller 28, such as if the radiator 12 is not present. The air is thus directed radially outward in the outflow direction. As a result of such a configuration, efficiency is increased and noise generation is positively influenced.

[0053] The invention is not restricted to the exemplary embodiments described above. On the contrary, other variants of the invention can also be derived therefrom by a person skilled in the art without departing from the subject matter of the invention. In particular, all the individual features described in connection with the individual exemplary embodiments can also be combined with one another in some other way without departing from the subject matter of the invention.

[0054] The following is a list of reference numbers shown in the Figures. However, it should be understood that the use of these terms is for illustrative purposes only with respect to one embodiment. And, use of reference numbers correlating a certain term that is both illustrated in the Figures and present in the claims is not intended to limit the claims to only cover the illustrated embodiment.

LIST OF REFERENCE SIGNS

[0055] 2 motor vehicle [0056] 4 internal combustion engine [0057] 6 wheel [0058] 8 radiator fan [0059] 10 line [0060] 12 radiator [0061] 14 fan frame [0062] 16 direction of travel [0063] 18 electric motor [0064] 20 aperture [0065] 22 rim [0066] 24 motor mount [0067] 26 hub [0068] 28 impeller [0069] 30 fan blades [0070] 32 outer ring [0071] 34 axis of rotation [0072] 36 dynamic pressure flap [0073] 38 flap [0074] 40 radially outer end [0075] 42 radially inner end [0076] 43 preferential direction of rotation [0077] 44 radially inner section [0078] 46 s-shaped section [0079] 48 leading edge [0080] 50 trailing edge

[0081] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.