Kühlerlüfter

Abstract

having cooling fans (4) - a fan frame (6) with a frame top (O) and a frame bottom (U) as well as with a fan wheel recess (10) which is surrounded by a frame ring (12), and - a fan wheel (8) rotatably arranged in the fan wheel recess (10) for conveying airflow along a conveying direction (F) from the top of the frame (O) to the bottom of the frame (U), - wherein the fan wheel (8) has a central hub pot (14) with a number of radially oriented blades (16) and an outer ring (24) connecting the blades (16) at their tips, - wherein a circumferential annular gap (26) is formed between the outer ring (24) and the frame ring (12), - wherein a rib structure (28) is introduced into the annular gap (26) to reduce the swirl of a gap flow oriented against the conveying direction (F), - wherein the rib structure (28) has a number of circumferentially distributed ribs (30) which project at least partially into the annular gap (26), - wherein the frame ring (12) extends axially beyond the outer ring (24) on the underside (U) of the frame with a frame ring section (40), - wherein the frame ring (12) has a circumferential step contour (48') with a radial step offset in the area of ​​the axially projecting frame section (40), which reduces the clear width between the frame ring (12) and the outer ring (24) at least in sections, - wherein the ribs (30) are designed as essentially freestanding walls and extend into the annular gap (26) starting from the step offset in the gap flow oriented against the conveying direction (F), - wherein the frame ring section (40) is oriented parallel radially inwards to the conveying direction (F), and - wherein a connecting line (V) from a radially outermost edge of an outer ring end surface (42) of the outer ring (24) to a radially innermost edge of a frame ring end surface (44) of the frame ring section (40) is inclined at an acute angle (W) between 25° and 35° relative to the conveying direction (F).

Description

[0001] The invention relates to a cooling fan, preferably electrically (electrically motorized), particularly for a motor vehicle, comprising a fan frame with a fan wheel recess and a fan wheel comprising an outer ring (shell ring), which is rotatably arranged or positioned in the fan wheel recess. The invention further relates to a cooling fan module, particularly as a pre-assembled unit.

[0002] Modern internal combustion engines, especially four-stroke engines in motor vehicles, are typically cooled with a coolant, usually a mixture of water, antifreeze, and corrosion inhibitor. The coolant is circulated through hoses, pipes, and / or channels through the internal combustion engine (cylinder head and engine block) and, if applicable, through thermally stressed components of the engine, such as an exhaust gas turbocharger, generator, or exhaust gas recirculation cooler. In this process, the coolant absorbs the heat energy generated by the combustion engine and dissipates it from these components.The heated coolant flows through a radiator, which is located at the front of the vehicle, and by means of which, according to the heat exchanger principle, an airflow absorbs the heat energy from the coolant and cools it down, before the cooled coolant flows back to the combustion engine, thus closing the coolant circuit.

[0003] A cooling system for an internal combustion engine, particularly in a motor vehicle, primarily dissipates the heat generated by the walls of the combustion chambers and cylinders. Since excessively high temperatures would damage the engine, for example by breaking down the lubricating film, burning the intake and / or exhaust valves for the fuel-air mixture, or similar issues, the engine must be actively cooled. To move air through the radiator, a radiator fan is positioned either upstream (i.e., upstream) or downstream (i.e., in the direction of airflow). This fan is driven either mechanically via a belt drive or electrically by an electric motor.

[0004] Electrically powered or electromechanically driven motor vehicles, such as electric or hybrid vehicles, typically include an electric motor as the electric drive system, which can drive one or both axles of the vehicle. For the purpose of supplying electrical energy, the electric motor is typically coupled to an in-vehicle (high-voltage) battery as an electrical energy storage device.

[0005] Electric motors, used as electric drive machines, generate comparatively little waste heat during operation, thus requiring significantly less cooling power compared to combustion engines. However, electrically powered or driveable vehicles face the additional problem that the battery begins to degrade at high temperatures, for example, above 45 °C. This means that at such elevated temperatures, electrochemical reactions occur within the battery, damaging or completely destroying it.

[0006] To improve electromobility, so-called fast-charging stations are often desired for electric or hybrid vehicles, where the vehicle's internal battery is charged within the shortest possible time. During such fast charging, comparatively high currents occur, which consequently cause an increase in battery temperature during the charging process.

[0007] The battery is typically charged when the vehicle is stationary, so there is no airflow for cooling. To improve cooling performance during (fast) charging, it is possible, for example, to use a radiator fan to generate a cooling airflow through a heat exchanger.

[0008] The following descriptions refer to a cooling fan with a fan shroud that has a fan wheel recess, and with a fan wheel that is rotatably mounted in the fan wheel recess. The fan shroud typically has a shroud ring that surrounds the fan wheel recess, and the fan wheel typically has an outer ring or casing ring that connects the tips of the fan blades circumferentially. A clear gap in the form of an annular gap or space, hereinafter also referred to as an annular gap, is formed between the outer ring of the fan wheel and the shroud ring of the fan shroud.

[0009] During the operation of such a cooling fan, a so-called backflow, leakage, or gap flow develops due to the pressure difference between the rotating fan wheel and the stationary cooling fan housing. This gap flow consists of a component from the ambient air and a component from the already conveyed airflow. The gap flow specifically refers to the airflow that forms in the gap area due to the negative pressure and which, because of the rotation of the fan wheel, is swirling, meaning it exhibits at least a certain angular momentum or a tangential flow component.

[0010] In certain applications, the swirling airflow at the gap leads to flow separation at the fan blades. This disrupts the desired airflow. In particular, the swirling airflow at the gap opposes the main flow, negatively affecting the airflow characteristics of the radiator fan module. The airflow at the gap, from the pressure side (away from the conveyed airflow) to the suction side (towards the conveyed airflow) of the radiator fan, is known to reduce the efficiency of the radiator fan and negatively impact the cooling performance of the cooling system. Furthermore, this airflow at the gap can sometimes result in very high noise levels, which reduces passenger comfort during vehicle operation.

[0011] The annular gap typically has an approximately L-shaped cross-section, which essentially acts as a labyrinth or gap seal, thus reducing the gap flow along the axial direction. To reduce swirl, for example, an annular rib structure is arranged within the gap geometry, which realigns the drawn-in swirling gap flow, leading to flow stabilization. This prevents flow separation.

[0012] Such a ribbed structure is known, for example, from US 7,762,769 B2 and EP 1 862 675 B1. The known ribbed structure interacts with a pocket or outlet bell of the frame ring, with the ribbed structure being arranged between the walls of the pocket.

[0013] In the following, the term "outlet bell" or "(frame ring) pocket" refers specifically to a section of the frame ring that is bent in an approximately U-shape along the axial or conveying direction of the cooling fan; that is, a frame ring section whose end face is oriented essentially against the conveying direction. In other words, the pocket area contains a cavity enclosed on three sides in the axial and radial directions, in which the rib structure is at least partially arranged.

[0014] Such outlet bells or (frame ring) pockets require a relatively large axial installation space, which is why such cooling fans are large along the axial direction.

[0015] From DE 10 2018 115 000 A1, a fan system comprising a fan hood and an annular fan with a hub, a plurality of fan blades, and an annular structure is known. The annular structure has a ring element and a flange element, wherein the ring element has a hollow cylindrical shape, and the flange element extends radially outward from the ring element. The fan hood has an annular hood flange, a hood body, and a plurality of hood guide blades, wherein the hood flange extends radially outward from the hood body and is arranged along the axis of rotation between the flange element and the hood body, the hood body being arranged around the ring element and comprising a first body section, a second body section, and a diverging nozzle.A return flow restrictor is formed by the hood body and the ring element at the point where the first and second sections of the hood body intersect. The diverging nozzle and the rear end of the ring element work together to form a dynamic sealing feature.

[0016] WO 2006 / 063825 A1 describes a ventilation system with a fan as the impeller. The fan, which is rotatably mounted about a main axis of rotation relative to a casing, has an outer ring and an outer radial rib extending from the outer cylindrical surface of the outer ring. The casing has an inner cylindrical surface spaced from and opposite the outer cylindrical surface of the outer ring; and a series of axial walls angularly distributed around the main axis of rotation. The casing further has an inner flange extending inwards from the inner cylindrical surface of the casing, with the radial flange positioned axially above the axial walls.

[0017] DE 692 28 189 T2 discloses a device comprising a plastic fan and a housing. A section of the housing is arranged outside an outer ring, the outer ring and the housing being dimensioned, configured, and arranged such that gaps are created between the outer ring and the housing, causing the recirculated airflow to move in a coiled recirculation path between the fan and the housing. Stationary flow control vanes are connected to the housing in such a position that they intersect and deflect the recirculated airflow.

[0018] The invention is based on the objective of providing a particularly suitable cooling fan. In particular, a cooling fan that is especially compact in the axial direction and enables reliable reduction of gap flow is to be provided. The invention is further based on the objective of providing a particularly suitable cooling fan module.

[0019] With regard to the cooling fan, the problem is solved according to the invention by the features of claim 1, and with regard to the cooling fan module by the features of claim 6. Advantageous embodiments and further developments are the subject of the dependent claims. The advantages and embodiments mentioned with regard to the cooling fan are also transferable to the cooling fan module and vice versa.

[0020] The radiator fan according to the invention is specifically designed and suitable for use in a motor vehicle. The radiator fan has a fan shroud with an upper and a lower surface, and a fan wheel recess serving as a passage opening from the upper to the lower surface. A fan wheel with an outer ring is inserted into the fan wheel recess. This outer ring connects the tips of blades extending radially from a (central) hub or hub cup. During operation, the fan wheel rotates, thereby conveying an airflow (main airflow, conveying airflow) from the upper to the lower surface of the shroud. The upper surface of the shroud is thus understood to be, in particular, the suction or inlet side, i.e., the intake side, of the radiator fan.Accordingly, the underside of the frame refers in particular to a pressure or outlet side, i.e., an outflow or outflow side, of the cooling fan.

[0021] The outer ring is also referred to as the outer band or outer band. Between the outer ring of the fan wheel and a frame ring (frame band) that surrounds or limits the fan wheel recess in the fan housing, an annular gap or space is formed – hereinafter referred to as the annular gap – which completely surrounds the outer ring.

[0022] A ribbed structure is incorporated into the annular gap to reduce the swirl of a gap flow oriented against the direction of flow. This ribbed structure acts as a barrier or (air) guide for the gap flow and is effective as such during operation of the cooling fan. The ribbed structure is designed such that when a swirling gap flow passes through the annular gap, it is at least partially guided over the ribbed structure, thereby reducing the swirl of the gap flow. In other words, the gap flow is de-swirled as it passes through the annular gap.

[0023] According to the invention, the frame ring extends axially beyond the outer ring on the underside of the frame, i.e., the pressure or outlet side. This frame ring section is therefore the portion or area of ​​the frame ring that projects axially beyond the outer ring on the underside of the frame. The frame ring section is oriented parallel to or at an angle radially inward to the conveying direction. This results in a particularly suitable cooling fan. In particular, it enables a cooling fan with a particularly flat design in terms of axial dimensions.

[0024] In this and the following, "axial" or "axial direction" refers specifically to a direction parallel (coaxial) to the axis of rotation of the fan wheel, i.e., perpendicular to the end faces of the radiator fan or the fan shroud. Similarly, in this and the following, "radial" or "radial direction" refers specifically to a direction oriented perpendicular (transverse) to the axis of rotation of the fan wheel along a radius of the fan wheel or shroud ring. In this and the following, "tangential" or "tangential direction" refers specifically to a direction along the circumference of the fan wheel or shroud ring (circumferential direction, azimuthal direction), i.e., a direction perpendicular to both the axial and radial directions.

[0025] The cooling fan according to the invention is preferably designed as an axial fan. Here and in the following, an axial fan is understood to be a cooling fan that draws in cooling air axially and expels it axially. This means that the axial fan conveys (expels) air outwards in an axial direction. The conveyance direction, i.e., the direction of the air or volume flow generated by the rotation of the fan wheel, is thus essentially parallel to the axial direction.

[0026] A "fan wheel" within the meaning of the present invention is, in particular, a rotationally symmetrical component comprising a hub, especially in the form of a hub housing, and a number of blades attached thereto. In the case of an electrically driven fan wheel, the hub provides the connection to the electric motor, in particular via a shaft projecting from it, so that a torque generated by the motor is transmitted to the fan wheel. The blades are designed and / or configured to generate an airflow as soon as the fan wheel is set into rotational motion.

[0027] A "hub body" within the meaning of the present invention is, in particular, a central part of the fan wheel, which, in the manner of a classic pot, is composed of a base surface and an adjoining cylindrical surface. In particular, the fan blades are arranged, and especially integrally formed, on this cylindrical outer wall. The hub body is located in the center of the fan wheel and provides a connection to a drive, in particular an electric motor, if the fan wheel is electrically driven. In this case, the hub body at least partially covers this drive.

[0028] A "blade" within the meaning of the present invention is a flat body which is radially oriented in a plane to which the axis of rotation is perpendicular and which is crescent-shaped in this plane and / or inclined relative to this plane. For the purposes of the present invention, a blade also includes a wing (fan blade) or a rotor blade. The blade is arranged on the hub and is designed, in particular configured, to generate an airflow as soon as the fan wheel is set into rotational motion.

[0029] In a suitable design, the axially projecting section of the frame ring is pocketless. In other words, the frame ring has no pocket or outlet bell, i.e., no three-sided enclosed cavity. This means that the frame ring section is oriented radially inwards to the conveying direction, either parallel to or at an acute angle. An "acute angle" or "acute angle" is defined as an angle less than or equal to 90°, i.e., an angle range between 0° and 90°.

[0030] The design is based on the understanding that a suitable geometric configuration of the annular gap or the frame ring section enables a positive influence on the flow pattern within the gap, comparable to a pocket or outlet bell. The frame ring section is particularly easy to manufacture and preferably requires less axial installation space than a pocket with the same effect.

[0031] According to the invention, an (imaginary) connecting line is inclined at an acute angle to the conveying direction from an outer ring end face on the underside of the frame, i.e., the end face of the outer ring facing the underside of the frame, to a frame ring end face of the frame ring section. The connecting line is oriented within an axial and radial cross-sectional plane. The connecting line essentially corresponds to the gap opening between the outer ring and the frame ring section, through which the gap flow enters. The angle being as acute or shallow as possible ensures a comparatively large inlet area, so that the gap flow can be reliably guided over the rib structure.

[0032] In a preferred embodiment, the axial distance between the outer ring end face and the frame ring end face is greater than the radial distance between the outer ring end face and the frame ring end face. The axial distance is understood here to be, in particular, the axial spacing between the points of the end faces that are oriented lowest along the conveying direction, i.e., those points that are closest to the underside of the frame. The frame ring section is the area of ​​the frame ring that extends along the axial distance, i.e., the area between the outer ring end face and the frame ring end face. The radial distance is understood here to be, in particular, the radial spacing between the radially outermost points of the outer ring end face and the radially innermost points of the frame ring end face.

[0033] The acute angle between the conveying direction and the connecting line corresponds to the arctangent of the ratio of the radial distance to the axial distance of the end faces. Because the axial distance is greater than or equal to the radial distance, or vice versa, the acute angle between the conveying direction and the connecting line in this embodiment is always less than or equal to 45°, i.e., within an angular range between 0° and 45°. Preferably, the angle is dimensioned, for example, between 15° and 45°, more preferably between 20° and 40°, and particularly at approximately 25°. This results in a particularly suitable opening of the annular gap.

[0034] In one possible design, the outer ring has a radial lip which is flush with the annular gap in the radial direction at the top of the frame. In other words, the radial lip is aligned with the gap opening on the top of the frame. The radial lip projects radially beyond the outer circumference of the outer ring. The radial lip overlaps the rib structure, at least partially.

[0035] According to the invention, the frame ring has an approximately radially oriented stepped offset on its upper surface in the area of ​​the gap opening, i.e., a radial intermediate section connecting two approximately axially oriented sections of the frame ring. The radial lip is arranged radially aligned with this stepped offset. The gap opening on the upper surface of the frame is thus formed between the radial lip and the stepped offset. This reduces the clear width between the outer ring and the frame ring, or between the radial lip and the stepped offset, resulting in a particularly narrow gap opening on the upper surface of the frame. The radial lip thus reduces the annular gap in the direction of the frame ring, so that the radial lip and the frame ring interact like a labyrinth seal. This ensures particularly reliable anti-swirl of the flow in the gap.

[0036] The invention provides that the rib structure comprises a number of circumferentially distributed ribs, which project radially into the annular gap at least partially. Preferably, the rib structure is designed with locally periodic, i.e., regularly repeating, preferably identical, ribs or rib elements, wherein the ribs are advantageously arranged equidistantly in the circumferential direction. For example, the ribs are arranged at an angular offset of approximately 10° along the circumferential or tangential direction. In other words, the rib structure is formed, for example, by 36 ribs arranged circumferentially around the inner circumference of the frame ring.

[0037] The ribs or rib elements exhibit, for example, a radially converging or eccentrically inclined rib profile. In a section plane oriented perpendicular to the axial direction, the ribs may have a triangular cross-sectional shape. Alternatively, the ribs may be designed as thin, essentially freestanding walls of the rib gap. In another alternative design, the rib structure may consist of a number of radial pockets with a rib effect.

[0038] In a preferred embodiment, the rib structure is integrally molded, i.e., monolithically, onto an inner circumference of the frame ring facing the outer ring. This means that both the gap geometry of the annular gap and the rib structure depend on the geometric design or construction of the frame ring. As a result, the frame ring exhibits advantageous functional integration, enabling particularly simple and flexible adaptation of the annular gap or the rib structure to a specific application. Advantageously, the frame ring is designed as an injection-molded part.

[0039] In a non-inventive embodiment, the frame ring section is oriented radially inwards to the conveying direction at an angle of inclination, in particular an acute angle of inclination. The frame ring section engages behind the outer ring, at least partially, in the radial direction. Preferably, the radial lip of the outer ring is engaged radially behind the frame ring section. This results in at least a certain radial offset between the gap opening on the upper side of the frame, which is formed in particular between the radial lip and the stepped offset of the frame ring, and between the gap opening on the lower side of the frame, which is formed in particular between the end face of the outer ring and the end face of the frame ring. In other words, the gap opening on the upper side of the frame is arranged radially outwards, and the gap opening on the lower side of the frame is arranged radially inwards.This further improves the effectiveness of the annular gap as a labyrinth seal.

[0040] In an advantageous embodiment, the frame ring has a circumferential contour in the area of ​​the annular gap, which reduces the clear width between the frame ring and the outer ring in the gap area, at least in sections. The contour particularly causes a radial narrowing of the annular gap along the axial direction. The contour is, for example, designed as a radially inwardly directed step offset and / or as a radially directed radial lip or ring wall of the frame ring. The contour is preferably continuous, i.e., arranged along the entire inner circumference of the frame ring, and additionally incorporates the rib structure, in particular the periodically arranged ribs. This achieves a particularly reliable and structurally simple de-swirling of the gap flow.

[0041] The cooling fan module according to the invention is preferably designed as a pre-assembled unit, which comprises the cooling fan described above and an electric motor, preferably designed as an internal rotor, which is held in the fan wheel recess of the fan frame by means of radially oriented struts. The rotor of the internal rotor is arranged in the hub of the fan wheel in a rotationally fixed manner, while the stator is held in the frame by means of the struts.

[0042] For the purposes of the invention, a "cooler fan module" is understood to be a cooler fan that is electrically driven (operated) and supplied as a pre-assembled component (module) together with the electric motor. The fan wheel is preferably mounted by means of (radially oriented) struts that connect the stationary part of a drive, in particular the stator of an electric motor, to the cooler frame, while the rotating part of the drive, in particular the rotor of the electric motor, is non-rotatably connected to the central hub housing, to which the radially oriented fan blades are attached, in particular integrally (monolithically) formed.

[0043] Exemplary embodiments of the invention are explained in more detail below with reference to a drawing. The drawing shows: Fig. 1 in perspective a cooling fan module with a fan frame and with a fan wheel rotatably arranged in a recess on the frame, which has a hub pot for receiving an electric motor and a number of blades whose blade tips are connected to an outer ring, Fig. 2 Top view of the cooling fan module looking at the top of a frame, Fig. 3 Top view of the cooling fan module looking at the underside of a frame, Fig. 4. Top view showing a section of a rib of a rib structure according to. Fig. 2, Fig. 5 in a sectional view along the section line VV according to Fig. 3 the area of ​​an annular gap between the outer ring of the fan wheel and a frame ring limiting the recess on the frame side, Fig. 6 in a sectional view along the section line VI-VI according to Fig. 3 the area of ​​a rib of the annular gap between the outer ring of the fan wheel and a frame ring limiting the recess on the frame side, Fig. 7 in schematic representation of the annular gap according to Fig. 5 and Fig. 6, and Fig. 8, Fig. 9, Fig. 10, Fig. 11, Fig. 12, Fig. 13, Fig. 14 to Fig. 15 different embodiments of the annular gap are shown in schematic representations.

[0044] Corresponding parts and directions are marked with the same reference symbols in all figures.

[0045] The Fig. Figure 1 shows a perspective view of a cooling fan module 2 with a cooling fan 4. The cooling fan 4 has a fan shroud 6 and a fan wheel 8.

[0046] A fan wheel recess 10 is formed in the fan frame 6, which is bounded by a frame ring 12. The fan wheel 8 has a central hub 14, to which a number of blades (fan vanes) 16 are formed on the outside, oriented in the radial direction R. As shown in particular in the Fig. As can be seen in Figure 2, the fan wheel 8 in this embodiment has nine blades 16. The blades 16 are only marked with reference numerals in the figures for illustrative purposes.

[0047] A motor mount or retaining ring 18 coupled to the hub housing 14 is arranged centrally within the fan wheel recess 10 and mechanically connected to the fan shroud 6 via struts 20. As shown in particular in the Fig. As can be seen in Figure 3, the motor mount 18 is held within the fan wheel recess 10 by means of ten struts 20. The struts 20 are only marked with reference symbols in the figures for illustrative purposes.

[0048] The motor holder 18 holds an electric motor (not shown in detail) whose rotor is surrounded by the stator. In other words, the electric motor is specifically designed as an internal rotor motor. Motor electronics 22 ( Fig. 3) is connected or connectable to an electrical power supply, for example to a vehicle electrical system, by means of lines guided on the struts 20. The radiator fan module 2 is designed and configured to be installed at the front of a vehicle. The radiator fan 4 is specifically designed as an axial fan.

[0049] The struts 20 are arranged in the direction of flow F of the airflow generated by the cooling fan module 2 during its operation, meaning in the axial direction A behind the fan wheel 8. The direction of flow F is defined here by a Fig. 2 shown top of frame or front of frame O to a in Fig. The stator is oriented towards the underside or rear of the frame U shown in Figure 3. The stator is thus connected to the struts 20 on the back of the fan wheel 8, either directly or indirectly via the motor mount 18. These struts are in turn connected to the fan frame 6. The stator of the electric motor is therefore rigidly connected to the fan frame 6, and the rotor of the electric motor, together with the fan wheel 8, is rotatably held in the fan wheel recess 10 of the fan frame 6.

[0050] The fan wheel 6, arranged in the fan wheel recess 10, is driven by the electric motor in the direction of rotation symbolized by arrow D in the figures during operation of the cooling fan module 2. The direction of rotation D is parallel to a tangential or circumferential direction of the fan wheel recess 10 or the frame ring 12. In this direction of rotation D, the blades 16 are concave at their leading edges 16a and substantially convex, and preferably wavy, at their trailing edges 16b.

[0051] The blades 16 are connected or mechanically coupled to each other at their tips 16c by means of a circumferential outer ring 24. The outer ring 24 serves, among other things, to stabilize the blades 16 during the rotation of the fan wheel 8. The outer ring 24 also guides the airflow and improves the aerodynamic properties of the fan wheel 6. A circumferential annular gap 26 is formed between the outer ring 24 (on the fan wheel side) and the frame ring 12 (on the recess side).

[0052] The cooling fan module 2 is preferably provided as a (pre-)assembled unit and thus comprises a cooling fan 4 formed by the fan frame 6 and the fan wheel 8, as well as the electric motor, whose rotor is arranged in a rotationally fixed manner in the hub pot (in the fan hub) 14 of the fan wheel 8, and whose stator is held in a frame-fixed manner in the fan wheel recess 10 of the fan frame 6 by means of the struts 20 oriented in the radial direction R (radially).

[0053] A ribbed structure 28 is incorporated into the annular gap 26 to reduce the swirl of a gap flow oriented against the direction of flow F. The ribbed structure 28 acts as an (air) guide structure for de-swirling the gap flow and is effective as such during operation of the cooling fan 4. The annular gap 26 is thus designed as a ribbed gap.

[0054] In the embodiment shown, the rib structure 28 has, for example, thirty-six (36) circumferentially distributed ribs or rib elements 30, which project radially into the annular gap 26 at least partially. The ribs 30 are arranged equidistantly in the circumferential direction, i.e., at an angular offset of approximately 10°, along the circumferential or tangential direction.

[0055] The ribs 30 or rib elements are formed as essentially freestanding walls of the rib gap 26 in one piece, i.e., monolithically, on an inner circumference 32 of the frame ring 12 facing the outer ring 24. As, for example, in the Fig. As can be seen in Figure 4, the ribs 30 have a radially converging rib inclination. The ribs 30 of the rib structure 26 are only marked with reference symbols in the figures as examples.

[0056] The gap geometry, i.e. the geometric cross-sectional shape of the annular gap 26, is determined from the sectional views of the Fig. 5 and Fig. 6 is shown in more detail. The sectional views are shown along the section lines VV and VI-VI of the Fig. Figures 3 are oriented and each shows a view of an axial-radial section plane, i.e., a section plane spanned by the axial direction A and the radial direction R. The section line VV runs through a rib-free area of ​​the annular gap 26, passing through a rib 30.

[0057] As seen in the sectional views of the Fig. 5 and the Fig. As is relatively clearly visible in Figure 6, the frame ring 12 has a radial step offset 34 on its upper surface O. This step offset 34 aligns along the radial direction R with a radial lip 36 of the outer ring 24 on the upper surface of the frame. The outer ring 24, together with the radial lip 36, has an approximately L-shaped cross-sectional form in the shown sectional planes, with the radial lip 36 extending as a horizontal leg of the L in a radial direction over the outer circumference of the outer ring 24. The radial lip 36 overlaps the rib structure 28, or rather its ribs 30, at least partially along the radial direction R. Between the step offset 34 of the frame ring 12 and the radial lip 36 of the outer ring 24, a gap opening 38 of the annular gap 26 is provided on the upper surface of the frame as an outflow or outlet opening for the gap flow.

[0058] The frame ring 12 extends axially beyond the outer ring 24 in the area of ​​the underside of the frame U, i.e., the pressure or outlet side of the fan wheel recess 10, with a frame ring section or (frame) ring extension 40. In the Fig. 5, Fig. 6 to Fig. In the embodiment shown in Figure 7, the frame ring section 40 is oriented radially inwards to the conveying direction at an angle of inclination NW. In the illustrated embodiment, the angle of inclination NW is approximately 45°. In other words, the frame ring section 40 is bent or folded radially inwards. The frame ring section 40 thus engages the radial lip 36 of the outer ring 24, at least partially, in the radial direction R. The frame ring section 40 is pocketless, i.e., it is designed without a frame ring pocket or outlet bell.

[0059] Towards the underside U of the frame, the outer ring 24 has an axially oriented outer ring end surface 42, and the frame ring section 40 has an axially oriented frame ring end surface 44. A radial distance dR and an axial distance dA exist between the outer ring end surface 42 and the frame ring end surface 44. The axial distance dA denotes the axial spacing between the approximately radially oriented end surfaces 42 and 44, while the radial distance dR denotes the radial spacing between the radially outermost edge of the outer ring end surface 42 and the radially innermost edge of the frame ring end surface 44.

[0060] In the exemplary embodiment of the Fig. 5 and Fig. In Figure 6, the axial distance dA is dimensioned larger than the radial distance dR. In particular, the axial distance dA is dimensioned approximately twice as large as the radial distance dR. A connecting line V, shown as a dashed line in the figures, between the end surfaces 42 and 44, which is shown by way of example from the radially outer lower edge of the outer ring end surface 42 to the radially inner lower edge of the frame ring end surface 44, has an acute angle W with respect to the conveying direction F, which in the illustrated embodiment is dimensioned to approximately 25°. The connecting line V essentially corresponds to a gap opening 46 facing the underside U of the frame, through which the gap flow can enter.

[0061] As especially in the Fig. As can be seen in Figure 6, the rib 30 is designed as a one-piece molded (radial) thickening of the material of the frame ring 12. The annular gap 26 has an approximately L-shaped cross-sectional form in the area of ​​the ribs 30, which acts as a labyrinth seal with respect to the gap flow.

[0062] In the Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11, Fig. 12, Fig. 13, Fig. 14 to Fig. 15 different gap geometries and rib structures 28 are shown in schematic and highly simplified representations.

[0063] When referring to an angle, the term "approximately" denotes, in particular, a certain angular range around the specified angle value, for example, ± 5°. For instance, an angle of approximately 45° is to be understood as (45 ± 5)°, i.e., as an angular range between 40° and 50°. With regard to lengths or ratios, such as the radial distance dR and the axial distance dA, the term "approximately" refers to a range of values ​​whose limits can be derived, in particular, from geometric relationships based on related angular measurements. For example, the radial distance dR and the axial distance dA are approximately equal for an angle W of approximately 45°; specifically, the ratio of the distances (dR / dA) is between 0.839 (arctan(40°)) and 1.192 (arctan(45°)).

[0064] The non-inventive embodiment of the Fig. 7 essentially corresponds to the embodiment described above according to the Fig. 5 and the Fig. 6, wherein the inclination angle NW and the angle W are each dimensioned to approximately 35°.

[0065] In the Fig. In the non-inventive embodiment shown in Figure 8, the frame ring section or ring extension 40 is oriented parallel to the conveying direction F or axial direction A. In other words, the angle of inclination NW is 0°. The radial distance dR is dimensioned larger than the axial distance dA, so that the angle W is greater than 45°, for example approximately 50°.

[0066] The frame ring 12 has a stepped contour 48 in the area of ​​the annular gap 26, i.e., in the area between the gap openings 38 and 46. The contour 48, hereinafter also referred to as the step contour 48, is formed circumferentially on the inner circumference 32 and causes a radial narrowing of the annular gap 26. In the embodiment of the Fig. In section 8, the step contour 48 exhibits a step offset which is inclined or kinked at an angle to the conveying direction. In other words, the frame ring 12 is set radially inwards at an unspecified acute angle of less than 90° in the area of ​​the step contour 48.

[0067] The non-inventive embodiment of the Fig. Figure 9 shows a gap geometry which is approximately the embodiment of the Fig. 8 corresponds, wherein the step contour 48' has a radially directed step offset, which places the frame ring 12 inwards at an angle of approximately 90° in the area of ​​the annular gap 26.

[0068] The Fig. Figure 10 shows a non-inventive embodiment of the gap geometry in which the frame ring section 40 is curved radially inwards. The frame ring section 40 is bent radially inwards at an angle of approximately 90°, so that the end surfaces 42, 44 are oriented approximately perpendicular to each other. In other words, the frame ring end surface 44 is oriented approximately axially. The axial distance dA is dimensioned larger than the radial distance dR, with the angle W of the connecting line V being approximately 35°.

[0069] The Fig. Figure 11 shows a gap geometry not according to the invention, with a frame ring section 40 oriented parallel to the conveying direction F, and a step contour 48' with a radial step offset. In contrast to the embodiment of the Fig. In section 9, the step contour 48' is not located in the area of ​​the slot opening 38 but in the area of ​​the axially opposite slot opening 46. In particular, the step offset of the step contour 48' is located approximately at the axial height of the outer ring end surface 42. The ribs 30 extend from the step offset in the opposite direction of conveying F. The axial distance dA and the radial distance dR are approximately equal in dimension, so that the angle W of the connecting line V is approximately 45°.

[0070] The Fig. Figure 12 shows an embodiment of the invention in which the step contour 48 is arranged in the region of the axially projecting frame ring section 40, i.e., axially below the outer ring end surface 42 in the conveying direction F. The ribs 30 extend from the step offset in the opposite direction to the conveying direction F. In other words, the ribs 30 extend at least partially over the frame ring section 40. The axially directed area of ​​the frame ring section 40 on the underside of the frame runs parallel to the conveying direction F, i.e., parallel to the axial direction A or the longitudinal direction of the outer ring 24. The axial distance dA is dimensioned larger than the radial distance dR, with the angle W of the connecting line V being approximately 30°.

[0071] In the Fig. Figure 13 shows a non-inventive embodiment of the gap geometry, in which the frame ring section 40 is aligned parallel to the conveying direction F. The radial distance dR is approximately twice the axial distance dA. The angle W of the connecting line V is approximately 65°.

[0072] In the Fig. Figure 14 shows a non-inventive embodiment of the gap geometry, in which the radial step offset of the step contour 48' is arranged approximately at half the axial height of the outer ring 24. The ribs 30 extend from the step offset in the opposite direction of conveying F. The frame ring section 40 is oriented parallel to the conveying direction F, with the radial distance dR being smaller than the axial distance dA, and the angle W of the connecting line V being approximately 35°.

[0073] The Fig. Figure 15 shows a non-inventive embodiment in which the frame ring section 40 is formed parallel to the conveying direction F. The radial distance dR is as in the embodiment of the Fig. The 13 is dimensioned approximately twice as large as the axial distance dA. The angle W of the connecting line V is approximately 65°. In this embodiment, the frame ring 12 is provided with a circumferential contour 50. The contour 50, hereinafter also referred to as the radial lip, is designed as a freestanding, radially extending ring wall, which is arranged at approximately half the axial height of the outer ring 24. With respect to the axial direction A or the conveying direction F, the ribs 30 extend above and below the radial lip 50.

[0074] Although exemplary embodiments were described in the preceding description, it should be noted that a multitude of modifications are possible. In particular, such an embodiment of the fan frame 6 according to the invention is also suitable for dissipating waste heat from components of a purely electric vehicle. Furthermore, it should be noted that the exemplary embodiments are merely examples and are not intended to restrict the scope of protection, the applications, or the construction in any way. Rather, the preceding description provides the person skilled in the art with a guideline for implementing at least one exemplary embodiment, whereby various modifications, particularly with regard to the function and arrangement of the described components, can be made without departing from the scope of protection as defined by the claims and these equivalent combinations of features. Reference symbol list 2 Cooling fan module 4 cooling fans 6 fan shroud 8 Fan wheel 10 Fan wheel cutout 12 Frame ring 14 Hub pot 16 shovel blade 16a Leading edge 16b trailing edge 16c leaf tip 18 Motor mounts 20 strut 22 Engine electronics 24 outer ring 26 annular gap 28 rib structure 30th rib 32 inner circumference 34 step offset 36 radial rib 38 Gap opening 40 Frame ring section 42 Outer ring end surface 44 Frame ring end surface 46 Gap opening 48, 48' contour / step contour 50 Contour / Radial Rib R Radial direction A Axial direction F Conveyor direction O Top of frame U bottom of frame Direction of rotation NW inclination angle dA distance / axial distance dR distance / radial distance V connecting line W angle

Claims

[1] having a cooling fan (4) - a fan frame (6) with a frame top (O) and a frame bottom (U) as well as with a fan wheel recess (10) which is surrounded by a frame ring (12), and - a fan wheel (8) rotatably arranged in the fan wheel recess (10) for conveying airflow along a conveying direction (F) from the top of the frame (O) to the bottom of the frame (U), - wherein the fan wheel (8) has a central hub pot (14) with a number of radially oriented blades (16) and an outer ring (24) connecting the blades (16) at their tips, - wherein a circumferential annular gap (26) is formed between the outer ring (24) and the frame ring (12), - wherein a rib structure (28) is introduced into the annular gap (26) to reduce the swirl of a gap flow oriented against the conveying direction (F), - wherein the rib structure (28) has a number of circumferentially distributed ribs (30) which project at least partially into the annular gap (26), - wherein the frame ring (12) extends axially beyond the outer ring (24) on the underside (U) of the frame with a frame ring section (40), - wherein the frame ring (12) has a circumferential step contour (48') with a radial step offset in the area of ​​the axially projecting frame section (40), which reduces the clear width between the frame ring (12) and the outer ring (24) at least in sections, - wherein the ribs (30) are designed as essentially freestanding walls and extend into the annular gap (26) starting from the step offset in the gap flow oriented against the conveying direction (F), - wherein the frame ring section (40) is oriented parallel radially inwards to the conveying direction (F), and - wherein a connecting line (V) from a radially outermost edge of an outer ring end surface (42) of the outer ring (24) to a radially innermost edge of a frame ring end surface (44) of the frame ring section (40) is inclined at an acute angle (W) between 25° and 35° relative to the conveying direction (F). [2] Cooling fan (4) according to claim 1, characterized by , that the axially projecting frame ring section (40) is designed without pockets. [3] Cooling fan (4) according to claim 1 or 2, characterized by , that an axial distance (dA) between the outer ring end surface (42) and the frame ring end surface (44) is greater than a radial distance (dR) between the outer ring end surface (42) and the frame ring end surface (44). [4] Cooling fan (4) according to one of claims 1 to 3, characterized by , that a radial lip (36) of the outer ring (24) is flush with the annular gap (26) in the radial direction (R) in the area of ​​the top of the frame (O). [5] Cooling fan (4) according to one of claims 1 to 4, characterized by , that the rib structure (28) is integrally formed on an inner circumference (32) of the frame ring (12) facing the outer ring (24). [6] Cooling fan module (2) comprising a cooling fan (4) according to one of claims 1 to 5, and an electric motor held in the fan wheel recess (10) of the fan frame (6) by means of radially oriented struts (20).

Images