EP3887684A1

EP3887684A1 - Impeller of a motor vehicle

Info

Publication number: EP3887684A1
Application number: EP20701598.3A
Authority: EP
Inventors: Michael Mauss
Original assignee: Brose Fahrzeugteile SE and Co KG
Current assignee: Brose Fahrzeugteile SE and Co KG
Priority date: 2019-01-23
Filing date: 2020-01-22
Publication date: 2021-10-06
Also published as: KR20210113349A; MA54324A; WO2020152211A1; DE202019100367U1; CN113366223A; US20220112901A1; JP2022523037A

Abstract

The invention relates to an impeller (28) of a motor vehicle (2), in particular a cooling fan (8), comprising a hub (26), to which a number of fan blades (30) are connected. The fan blades (30) are inclined in relation to a rotational axis (34) of the impeller (28) and have in each case a section (46) which in the top view is S-shaped along the rotational axis (34). The invention further relates to a cooling fan (8) of a motor vehicle (2).

Description

description

Fan wheel of a motor vehicle

The invention relates to a fan wheel of a motor vehicle, with a hub to which a number of fan blades are connected. The fan wheel is preferably an integral part of a radiator fan of the motor vehicle. The invention further relates to a radiator fan of a motor vehicle, such as a main fan.

Motor vehicles with an internal combustion engine generate considerable heat during operation. To maintain the operating temperature of the internal combustion engine and also for the operation of an air conditioning system, a liquid coolant is usually used, which in turn has to be cooled. This is usually done by means of a coolant network acted upon by an air stream, which is in heat exchange with the coolant. For example, the coolant is conducted into pipes that are incorporated into the cooler network. Since in particular at low vehicle speeds the airstream is normally not sufficient for cooling, it is known to use an electric fan by means of which the airstream is increased. The fan is arranged behind the cooler network in the direction of travel. With the help of a fan wheel of the fan, the air is sucked through the cooler network and directed to the internal combustion engine. There, the air absorbs excess heat from the internal combustion engine and transports it away. Here, the air hits the internal combustion engine essentially bluntly and is deflected by it, for example by 90 °. As a result, turbulence occurs which leads to an increase in flow resistance and thus to a decrease in the air volume throughput. There is also a noise development, which may be annoying. The invention has for its object to provide a particularly suitable fan wheel of a motor vehicle and a particularly suitable radiator fan of a motor vehicle, in particular an air volume throughput is increased.

With regard to the fan wheel, this object is achieved according to the invention by the features of claim 1 and in terms of the radiator fan by the features of claim 10. Advantageous further developments and refinements are the subject of the respective subclaims.

The fan wheel is a component of a motor vehicle and in particular a component of a radiator fan. Here, the fan wheel is suitable, in particular seen and set up to suck or blow air through a radiator of the motor vehicle. The radiator fan and thus also the fan wheel are preferably used to cool an internal combustion engine of the motor vehicle. A coolant is suitably cooled by means of the cooler, and / or an air flow is directed onto the possible internal combustion engine by means of the fan wheel. As an alternative to this, the fan wheel is, for example, a component of a blower, by means of which in particular air is conveyed into an interior of a motor vehicle. The motor vehicle is suitably land-bound and for example a passenger car (car). Alternatively, the motor vehicle is a utility vehicle, for example a truck (truck) or a bus.

The fan wheel has, in particular, an essentially flat design. At least, however, the expansion of the fan wheel in one plane is larger than perpendicular to it. The fan wheel is suitable, in particular provided and set up, to be rotated about an axis of rotation. In particular, the axis of rotation is perpendicular to the plane within which the fan wheel is arranged. The fan wheel is preferably an axial fan. This means that air is moved along the axis of rotation when the fan wheel is used.

The diameter of the fan wheel is expediently between 20 cm and 50 cm, between 25 cm and 45 cm and for example essentially equal to 30 cm, where there is expediently a deviation of 5 cm, 2 cm or 0 centimeters.

The fan wheel itself has a hub to which a number of fan blades are connected. The hub is suitable, in particular provided and set up, for being attached to an electric motor. In the assembled state, any electric motor is expediently attached to the hub, by means of which the fan wheel is rotated about the axis of rotation. Here, the hub is suitably arranged concentrically to the axis of rotation, which reduces an imbalance and thus unwanted noise and excessive stress. The hub is preferably designed essentially in the shape of a pot, a bottom of the pot advantageously being arranged substantially perpendicular to the axis of rotation. The fan blades are suitably connected to an outer periphery of a wall of the cup-shaped hub. If the hub is pot-shaped, the pot opening is expediently arranged against any air flow, in particular a direction of wind and / or a direction of movement of the motor vehicle. Air resistance is thus reduced. The hub is expediently essentially smooth on the outside. The fan blades are connected to the hub and, for example, in one piece with it. The complete fan wheel is expediently in one piece, which simplifies production. The fan wheel is particularly preferably made of a plastic, so that a weight is reduced and a shape is simplified. In this case, the fan wheel is particularly preferably produced in a plastic injection molding process. The fan blades, in particular also referred to as fan blades, are preferably identical to one another, which simplifies manufacturing and assembly. The fan blades are inclined with respect to the axis of rotation. Thus, each of the fan blades each have a main direction of expansion, which is inclined with respect to the axis of rotation. In particular, an angle between 10 ° and 80 ° or between 20 ° and 70 ° is formed. Due to the inclination, the fan wheel moves air in the axial direction during operation, that is to say along the axis of rotation or at least parallel to it. Each of the fan blades also has one essentially radial course, in particular with respect to the axis of rotation, so that the fan blades point outwards from the hub.

Each of the fan blades each has a section which is configured in an S-shape along the axis of rotation in a plan view. Thus, each of the fan blades is curved differently in the tangential direction with respect to the axis of rotation in the respective section. Consequently, each of the fan blades not only has a course in the radial direction but also in the tangential direction, the tangential direction changing here, so that there is not just a single curvature. For example, each of the fan blades also has a further section which, for example, is straight and essentially runs radially. Alternatively, the further section is configured, for example, in a plan view along the axis of rotation in a C-shape. In particular, each of the fan blades comprises several other sections. In an alternative to this, each fan blade is formed in each case by means of the s-shaped section.

In particular, the course of each fan blade in the area of the hub is essentially radial, that is to say in particular strictly radial, or there is a deviation of 5 °, 2 ° or 1 °. Because of the s-shaped section, the radially outer end of each fan blade is offset in the respective tangential direction with respect to its radially inner end. For example, the respective radial outer end has a radial and tangential course. Particularly preferably, however, the radially outer end expediently runs only in the radial direction, for example with a deviation of 10 °, 5 °, 2 ° or 0 ° from the strictly radial direction. For example, the complete S-shaped section is offset in the preferred direction of rotation with respect to further components of the respective fan blade. Only the radially outer end is offset against the preferred direction of rotation, at least with respect to other components of the S-shaped section.

Due to the S-shaped section, each fan blade works both in the manner of a nozzle and a diffuser. Thus, in the air flow that passes through the fan wheel during operation, a loading that is directed radially outward with respect to the axis of rotation is Motion component introduced so that the air flow in the air flow direction, which is in particular parallel to the axis of rotation, passes through a larger area behind the fan wheel than is covered by the fan wheel. Due to the increased area, a speed of the air flow is reduced and consequently a pressure is increased. Therefore, an increased air volume is conveyed by the fan wheel, wherein a rotational speed of the fan wheel is not increased. As a result, it can be operated with essentially the same output. In summary, a volume flow, i.e. the air volume throughput, is increased, so that cooling performance is improved. Alternatively, it is possible to operate the fan wheel at a lower rotational speed with the same air volume throughput, which reduces noise.

In addition, due to the introduction of the radial movement component into the air flow by means of the fan wheel, the air flow is fanned out, so that the air flow in particular does not bluntly hit an object arranged behind it, such as an internal combustion engine. This results in less turbulence and turbulence in the air flow, which in turn increases efficiency and reduces noise. Furthermore, a separation of the air flow from the component of the fan wheel is avoided and thus further turbulence is avoided, which likewise leads to an increase in efficiency and avoidance of excessive noise.

In particular, it is possible to operate the fan wheel in the two different directions of rotation due to the s-shaped section with respect to the axis of rotation. Particularly preferably, however, the fan wheel has only one preferred direction of rotation. Here, the fan wheel can be operated in particular only in the preferred rotational direction. For example, the fan blades have an aerodynamic profile perpendicular to their course and / or to the respective radial direction, which profile expediently has a thickening. Due to the aerodynamic profile, conveying the air flow is improved. In particular, the cross section of each fan blade is constant, in particular perpendicular to the respective radial direction. Thus, the cross section does not change due to the S-shaped configuration, which simplifies production. In particular, due to the S-shaped configuration of the section, the ra dialen ends of the fan blades are offset against the preferred direction. In other words, the fan blades are arranged in such a way that the end which is the most distant in the preferred direction of rotation in the tangential direction is located in front of the radial end of the fan blade, in particular in front of both radial ends of the fan blade. At least, however, the radially outer end of each fan blade does not form the tangential end of the fan blade in the preferred direction of rotation. Due to such an arrangement, separation of an air flow in the region of the radial ends of the fan blades is avoided, so that comparatively little turbulence is introduced into the air flow passing through the fan wheel and promoted by the latter. This further increases efficiency and further reduces noise.

For example, a rear edge of each fan blade with respect to the preferred direction of rotation is straight in a plan view in the preferred direction of rotation. In other words, the edge expediently has only a radial and possibly tangential course. In the axial direction, however, i.e. parallel to the axis of rotation, the edge has no extension. However, the rear edge of the fan blades with respect to the preferred direction of rotation is particularly preferably corrugated in a plan view in the preferred direction. The edge thus has an extent in the axial direction, that is to say parallel to the axis of rotation, which alternates in particular in the tangential direction. A wave form is expediently formed by means of the edge, that is to say expediently a sinusoidal shape or essentially sinusoidal shape. For example, the cross section parallel to the axis of rotation in the area of the rear end of each fan blade is designed in a wave shape. Due to the wave form, there is an improved volume throughput of the air, which is why the efficiency is further increased. Here, a suitable flow profile is introduced into the air flow passing through the fan wheel by means of the wave-shaped configuration of the rear edge. In particular, because of this, an additional radially outward movement component is introduced into the air flow, so that an air volume throughput is further increased. For example, the front edge of the fan blades with respect to the preferred direction of rotation is wave-shaped in a plan view against the preferred direction. However, this edge is particularly preferably straight. Guiding the air along the fan blades is thus improved. The front edge is particularly preferably rounded, which reduces flow resistance. Preferably, the front edge of the fan blades is straight and the rear edge of the fan blades, each with respect to the preferred direction of rotation, wave-shaped, with a continuous transition or at least partially continuous transition taking place between the edges. In other words, each of the fan blades is infinitely variable. Flow resistance is thus further reduced.

For example, the s-shaped section is arranged in the radial direction essentially in the middle of the respective fan blade. As an alternative to this, in particular the radially inner end of each fan blade is formed by means of the S-shaped section. However, it is particularly preferred that each of the S-shaped sections is offset outwards with respect to the rotational axis in each case in ra dialer direction. In other words, each of the S-shaped sections is preferably in the outer half of each of the fan blades. For example, the outer half of each fan blade is formed by means of the s-shaped section. The radially inner part of each fan blade is, for example, straight or c-shaped in a plan view. In the radially outer area of the fan wheel, the fan blades have an increased speed, so that an effect of the s-shaped section in this area is increased. In addition, an air volume moved by means of the fan blades is increased in this area. In other words, in this case, the essentially largest possible volume flow of air is moved by means of the S-shaped section.

For example, the orientation of the fan blades alternates in the tangential direction, so that the S-shaped sections face each other. However, it is preferred that the s-shaped sections face in the same direction. Alternatively or in combination in each case, for example, the s-shaped sections are spaced differently from the hub in the radial direction. In particular, here the distances alternate between in the tangential direction adjacent fan blades. The fan blades are expediently arranged rotationally symmetrically with respect to the hub. The angle of symmetry is preferably 360 ° divided by the number of fan blades. The fully permanent fan wheel is particularly preferably designed to be rotationally symmetrical, the angle of rotation in particular being 360 ° divided by the number of fan blades. Because of the rotationally symmetrical configuration, an imbalance is prevented or at least reduced, so that noise during operation is reduced. It also reduces the load on the mechanical component of the fan wheel and associated components, in particular on the electric motor, if any.

For example, the fan blades are designed tapered, the taper being, for example, in the radial direction. The respective radially outer end of each fan blade has a smaller extent in the tangential direction and / or perpendicular to the respective radial direction than the radially inner end. As an alternative to this, the radially inner end or an intermediate region of the fan blade is tapered. Particularly preferably, however, the expansion of each fan blade does not change in the tangential direction, or the change is less than 10% of the expansion of the respective fan blade in the tangential direction. The change is particularly preferably less than 5% of the extent of the respective fan blade in the tangential direction. This simplifies production and reduces weight, while still creating a comparatively robust fan wheel. Adaptation and, in particular, simulation are also simplified. In addition, a comparatively large volume of air is conveyed in this way by means of each of the fan blades.

For example, each of the fan blades ends bluntly in the radial direction. Alternatively, the radially outer ends of the fan blades are bent, in particular in the manner of a winglet. However, particularly preferably, the fan wheel has an outer ring which is arranged concentrically with the hub and to which the radially outer ends of the fan blades are connected. The fan blades are thus stabilized using the outer ring. The outer ring is, for example, essentially hollow-cylindrical. For example, the outer ring faces axially Direction, that is parallel to the axis of rotation, an expansion between 1 cm and 10 cm, for example between 2 cm and 5 cm and suitably equal to 3 cm.

By means of the outer ring, in particular leakage air between the fan wheel and any fan frame surrounding the fan wheel on the circumference is limited or prevented. For this purpose, a seal is expediently connected to an outer side of the outer ring, for example a brush seal. Al ternatively or in combination, the outer ring is made at least in sections in the manner of a labyrinth seal and consequently expediently has a contour which engages in a corresponding contour in the assembled state, in particular any fan frame, but is spaced from it. Thus, on the one hand, friction is not increased and, on the other hand, air is prevented from passing between the fan wheel and the frame, in particular against the direction of travel. Efficiency is thus further increased.

The radiator fan is a component of a motor vehicle and is expediently used to cool an internal combustion engine. In other words, the radiator fan is a main fan. Alternatively, the radiator fan is, for example, a component of an air conditioning system or an auxiliary unit of the motor vehicle. The radiator fan expediently comprises a cooler, which in particular has a cooling network, through which a number of tubes are preferably guided. The cooler network is, for example, thermally contacted with the pipes. A coolant is preferably conducted within half of the tubes during operation. The cooling network is, for example, essentially cuboid. The radiator fan also includes a fan frame with a round recess. Within half of the round recess, a fan wheel with a hub is arranged, expediently parallel to this and / or the fan frame, to which a number of fan blades is connected, which are inclined with respect to an axis of rotation of the fan wheel. The fan blades each have a section which is designed in an S-shape in a plan view along the axis of rotation. Preferably, the fan wheel is arranged concentrically to the recess. In addition, the radiator fan comprises an electric motor, which is, for example, a brushed commutator motor or preferably a brushless DC motor (BLDC). The electric motor is attached to the fan frame. For example, the fan frame includes a motor bracket that is held above the recess by means of a number of struts. Here, a rotation axis of the electric motor is arranged perpendicular to the recess and runs in particular on the axis of rotation of the fan wheel, preferably on a straight line that extends through the center point of the recess. For example, the electric motor is glued or screwed to the motor holder. The electric motor is thus held comparatively securely on the motor mount.

The fan wheel is driven by the electric motor and preferably connected to the sem, for example on a shaft of the electric motor. For example, the hub is mechanically coupled directly to the electric motor. For example, the fan wheel additionally includes the outer ring to which the fan blades are connected at their radial ends. By means of the outer ring, the fan blades are stabilized, which improves an acoustic impression. In particular, the outer ring engages in a corresponding receptacle or contour of the fan frame, these being preferably spaced apart from one another. In particular, a labyrinth seal is formed between them. This prevents leakage air from spreading. Alternatively or in combination, a brush seal or the like is arranged between the outer ring and the fan frame.

The fan frame is preferably connected to the cooler, suitably fastened. For example, the fan frame is screwed to the cooler or glued to it. In particular, the fan frame covered the possible cooler network. In other words, the fan frame is congruent with the cooler network or, for example, the complete cooler. A passage of air between the cooler and the fan frame is thus prevented, and the fan frame consequently results in comparatively efficient guidance of the air. The fan frame is preferably arranged on the downstream side of the cooler, ie expediently behind the cooler in the direction of travel of the motor vehicle. The advantages and further developments mentioned in connection with the fan wheel can also be applied analogously to the radiator fan and vice versa. Exemplary embodiments of the invention are explained in more detail below with reference to a drawing. In it show:

1 schematically shows a land-based motor vehicle with a radiator fan,

Fig. 2 schematically simplified in an exploded view partially

Radiator fan with a fan wheel,

3 is a top view of the fan wheel,

4 is a top view of the fan wheel,

5 shows an alternative embodiment of the fan wheel, and FIG

6 shows the fan wheel according to FIG. 5 in a top view of a fan blade against a direction of rotation

Corresponding parts are provided with the same reference characters in all figures.

In Figure 1, a motor vehicle 2 with a combustion engine 4 is shown schematically simplified. The internal combustion engine 4 drives the motor vehicle 2. 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 in more detail). In addition, the motor vehicle 2 comprises a radiator fan 8, which cools the internal combustion engine 4 serves. Thus, the radiator fan 8 is a main fan of the motor vehicle 2. The radiator fan 8 is fluidically connected by means of a number of lines 10 to the internal combustion engine 4, through which, during operation, a cooling liquid from the radiator fan 8 to the combustion engine 4 and passed through cooling channels there becomes. Excess heat is absorbed by the cooling liquid and leads back to the radiator fan 8, by means of which cooling of the cooling liquid takes place. The radiator fan 8 has a cooler 12 with a cooling network, not shown, through which a number of tubes are guided and thermally contacted with it. The tubes are fluidly coupled to the lines 10, so that the coolant is passed through the tubes during operation. The radiator fan 8 further comprises a fan frame 14 which is arranged in a direction 16 of the motor vehicle 2 behind the radiator 12. On the fan frame 14, an electric motor 18 is attached. In operation, the airstream flows through the cooler 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 cooler 12 by means of the electric motor 18, so that the cooler 12 is permeated by the air flow during operation, or at least depending on existing requirements. The cooler 12 is thus cooled, which is why the cooler fan 8 does not overheat even after the internal combustion engine 4 has been in operation for a comparatively long time. In addition, by means of the fan frame 14, the air passing through the cooling fan 8 is passed to the internal combustion engine 4 and this is additionally cooled from the outside in this way.

In Figure 2, the cooling fan 8 is shown schematically simplified in an exploded view, the cooler 12 being omitted. On the Küh ler 12, the fan frame 14 is attached, which completely covers the radiator network, not shown, and is congruent with this. The fan frame 14 is essentially flat and has a round recess 20 which is oriented perpendicular to the direction of travel 16. The cutout 20 has a diameter of 30 cm and is surrounded on the circumferential side by an edge 22 which is hollow-cylindrical and is arranged concentrically with the cutout 20. The diameter of the edge 22 is equal to the diameter of the recess 20, and the edge 24 has a length of 2 cm in the axial direction with respect to the recess 22, that is to say parallel to the direction of travel 16. In the assembled state, the edge 22 is located on the side of the fan frame facing away from the cooler 12 The fan frame 14 further includes a motor bracket 24, which is arranged against the direction of travel 16 above the recess 20. In the assembled state, the electric motor 18 is held by means of the motor mount 24 and the electric motor 18 is thus fastened to it. Here, the electric motor 18 is located on the side of the fan frame 14 opposite the cooler 12. A shaft 34 of the electric motor 18 protrudes in the direction of travel 16 through the motor mount 32 and is fastened in a rotationally fixed manner to a hub 26 of a fan wheel 28. The fan wheel 38 is thus driven by means of the electric motor 18, which is held by means of the motor holder 24. A number of fan blades 30 are connected to the hub 26, which are circumferentially surrounded by an outer ring 32 and connected to the latter. The hub 26, the fan blades 30 and the outer ring 32 are made in one piece from a plastic injection molding process.

In the assembled state, the fan wheel 28 is arranged parallel to the recess 22, the outer ring 32 being surrounded radially on the circumferential side by means of the edge 24. In operation, the fan wheel 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 recess 20. Air is thus sucked through the recess 22 against the direction of travel 16 during operation. A flow of air between the outer ring 32 and the rim 24 is prevented due to a seal, not shown, for example a labyrinth seal.

In addition, the fan frame 14 comprises a dynamic pressure flap 36 which encloses an opening which is 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, in particular when the motor vehicle 2 is moving comparatively quickly, the passage of the air through the recess 20 is partially hindered due to the fan wheel 28 or the fan wheel 28 would have to be comparatively fast be rotated. However, this would lead to an increased load on the electric motor 18 and the further components and an increased noise level. Above a certain pressure, the flap 38 is therefore pivoted and the opening is opened so that air can flow through it. An air throughput through the cooler 12, which is located in the direction of travel 16 in front of the fan frame 14, is thus increased. When the air pressure in front of the fan frame 14 is comparatively low, as is the case when the motor vehicle 2 is at a standstill, the flap 38 is closed, so that the formation of a circular air flow that only passes through the opening of the dynamic pressure flap 36 and the recess 22 is prevented. Thus, the cooler 12 is always penetrated by means of a sufficient air flow.

3 shows the fan wheel 28 in a plan view along the axis of rotation 34, counter to the direction of travel 16. In FIG. 4, the fan wheel 28 is shown enlarged in sections corresponding to the illustration in FIG. 3. The hub 26 is pot-shaped and the bottom of the hub 26 points in the direction of travel 16. The fan blades 30 are connected to an outer wall of the hub 26. In the variant shown here, the fan wheel 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. Since the complete fan wheel 28 is rotationally symmetrical, with the symmetry angle corresponding to 40 °.

The fan blades 30, whose radially outer end 40 is connected to the outer ring 32, are arranged in the radial direction with respect to the axis of rotation 34 between the outer ring 32 and the hub 26. The outer ring 32 is concentric with the Na be 26 and consequently also with the axis of rotation 34. The radially inner end 42 of each fan blade 30 is connected to the hub 26 and molded there. Each fan blade 30 has an essentially radial course in the region of the two radial ends 40, 42.

Each fan blade 30 is inclined with respect to the axis of rotation 34 and has an angle of between 80 ° and 60 ° to it, so that a comparatively effective movement of the air along the axis of rotation 34 is made possible through the openings formed between the fan blades 30. Due to the inclination of the fan blades 30, a preferred direction of rotation 43 is formed. When the fan wheel 28 rotates about the axis of rotation 34 in the preferred direction of rotation 43, air is sucked through the cooler 12 by means of the fan wheel 28. With a different direction of rotation the air would move in the direction of travel 16 through the cooler 12. To improve efficiency, the fan blades 30 are also profiled, and thus have an aerodynamic profile. This increases the air throughput. In summary, the fan wheel 28 has a preferred direction of rotation 43 about the axis of rotation 34.

Each fan blade 30 has a radially inner portion 44 which is designed in a substantially rectilinear radial or slightly C-shaped in a plan view along the axis of rotation 34. The radially inner section 44 has the radially inner end 42 and merges into an S-shaped section 46 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. Due to the S-shaped configuration of section 46, the radial outer ends 40 of the fan blades 30 are offset against a preferred direction of rotation 48, the complete S-shaped section 46 being offset in the preferred direction of rotation 43 with respect to the respective radially inner section 44.

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. Here, the expansion of each fan blade 30 in the tangential direction, that is parallel to the preferred direction of rotation 43, does not change or only Lich by less than 5% of the expansion 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, along the preferred direction of rotation 43. This enables a comparatively effective movement of the air.

Because of the S-shaped section 46, the fan wheel 28 acts on the upstream side, that is on the side of the cooler 12, in the manner of a nozzle and on the downstream side, that is on the side opposite the cooler 12, in the manner of a diffuser. Thus, an additional radial movement component is introduced into the air flow, which is generated or at least amplified by means of the fan wheel 28, and is thus directed away from the internal combustion engine 4. The air flow thus does not impinge on the internal combustion engine 4, which leads to reduced turbulence. Is also ne area penetrated by means of the air flow on the downstream side, that is to say counter to the direction of travel 16, is enlarged in comparison with the size of the cutout 20, so that a speed of the air is reduced and consequently a pressure is increased. As a result, an air volume throughput through the fan frame 14 and therefore also through the cooler 12 is increased at the same rotational speed about the axis of rotation 34. This also increases efficiency. Alternatively, it is possible to rotate the fan wheel 28 at a lower rotational speed and thus to use a less powerful electric motor 18, which reduces manufacturing costs. Noise is also reduced. In addition, tearing off of the air flow in the area of the outer ring 32 is reduced or avoided, which further increases the efficiency.

A modification of the fan wheel 28 is shown in FIG. 5, as shown in FIG. 4, the outer ring 32 and the hub 26 and the number of fan blades 30 not being changed. As in the previous example, each fan blade 30 also has a front edge 48 in the preferred direction of rotation 43. The front edge 48 is also S-shaped in the area of the S-shaped section 46. The front edge 48 has a rounding over its entire length perpendicular to its course, but is otherwise straight. In other words, the front edge 48 has no course in the axial direction, that is to say parallel to the axis of rotation 34. In summary, the front edge 48 of the fan blades 30 with respect to the direction of rotation 43 is straight in a plan view ent against the direction of rotation 43.

In comparison to the previous embodiment, however, the rear edge 50 is no longer straight in a plan view in the preferred direction 34. Rather, the rear edge 50 of the fan blades 30 with respect to the preferred direction of rotation 43 is corrugated in a plan view in the preferred direction of rotation 34, as shown in FIG. The rear edge 50 thus has a wave shape, in particular a sinusoidal shape. Here, both the radially inner section 44 and the s-shaped section 46 are undulating in the region of the rear edge 50. The area between the two edges 48, 50 runs essentially continuously, but at least continuously, between the two edges 48, 50 In the preceding example, the rear edge 50 is offset with respect to the front edge 48 due to the inclination against the direction of travel 16, so that the preferred direction of rotation 43 results. In summary, each of the fan blades 30, that is to say each blade, has the S-shaped section 46, which is designed in particular in a boomerang shape in the manner of a blade guard. By means of this configuration, separation of the air flow from the outer ring 32 is prevented or at least reduced, in particular if the cooler 12 is present. In addition, a movement component is introduced in the radial direction to the outside in the air flow passing the fan wheel 28, in particular if the cooler 12 is not present. Thus, the air is directed radially outward in the downstream direction. Because of such a configuration, the efficiency is increased and noise development is positively influenced.

The invention is not restricted to the exemplary embodiments described above. Rather, other variants of the invention can be derived therefrom by the person skilled in the art without leaving the subject matter of the invention. In particular, all of the individual features described in connection with the individual exemplary embodiments can also be combined with one another in other ways without departing from the subject matter of the invention.

Reference list

2 motor vehicle

4 internal combustion engine 6 wheel

8 radiator fans

10 line

12 coolers

14 fan frame

16 direction of travel

18 electric motor

20 recess

22 margin

24 motor bracket

26 hub

28 fan wheel

30 fan blades

32 outer ring

34 axis of rotation

36 dynamic pressure flap

38 flap

40 radially outer end

42 radially inner end

43 preferred direction of rotation 44 radially inner section

46 s-shaped section

48 leading edge

50 rear edge

Claims

Expectations

1. Fan wheel (28) of a motor vehicle (2), in particular a radiator fan (8), with a hub (26) on which a number of fan blades (30) is attached to the, which with respect to an axis of rotation (34) of the fan wheel (34 ) are inclined, and each have a section (46) which is designed in an S-shape in a plan view along the axis of rotation (34).

2. fan wheel (28) according to claim 1,

marked by

a preferred direction of rotation (43) about the axis of rotation (34).

3. fan wheel (28) according to claim 2,

characterized,

that due to the S-shaped configuration of the section (46), the radia len outer ends (40) of the fan blades (30) are offset against the preferred direction of rotation (43).

4. fan wheel (28) according to claim 2 or 3,

characterized,

that a rear edge (50) of the fan blades (30) with respect to the preferred direction of rotation (43) is corrugated in a plan view in the preferred direction of rotation (34).

5. fan wheel (28) according to one of claims 2 to 4,

characterized,

that a front edge (48) of the fan blades (30) with respect to the preferred direction of rotation (43) is straight in a plan view against the preferred direction of rotation (43).

6. fan wheel (28) according to any one of claims 1 to 5,

characterized, that the S-shaped sections (46) are each offset in a radial direction with respect to the axis of rotation (34) to the outside.

7. fan wheel (28) according to one of claims 1 to 6,

characterized,

that the fan blades (30) are arranged rotationally symmetrical with respect to the hub (26).

8. fan wheel (28) according to any one of claims 1 to 7,

characterized,

that the change in the expansion of each fan blade (30) in the tangential direction is less than 10%, in particular 5%, of the expansion of the respective fan blade (30) in the tangential direction.

9. fan wheel (28) according to any one of claims 1 to 8,

characterized,

that the fan blades (30) are connected at their radial outer end (40) to an outer ring (32) arranged concentrically to the hub (26).

10. Radiator fan (8) of a motor vehicle (2), in particular main fan, with egg ner fan frame (14) which has a round recess (20) within which a fan wheel (28) according to one of claims 1 to 9 and arranged by means of a Electric motor (18) is driven, which is connected to the fan frame (14).