CN113803149A - Fan with cooling device - Google Patents

Abstract

The invention relates to a fan (10), in particular an engine cooling fan in a motor vehicle, having an electric drive (18) with a rotor (42), a stator (40) and a control electronics (70) with a substantially flat, radially (32) extending printed circuit board (71) for the control electronics (18) and a substantially fluid-tight electronics housing (80) in which the control electronics (70) are arranged and a cooling air guide (90) which is designed to introduce a cooling air flow (122, 124) into the electric drive (18). It is proposed that a projection surface (112) of the stator (40) on a radial plane (102) is larger than a projection surface (110) of the electronics housing on the radial plane, wherein the cooling air guide (90) is arranged predominantly in an extension region (104) of the projection surface (112) of the stator (40), which is not covered by the projection surface (110) of the electronics housing (80).

Description

Fan with cooling device

Technical Field

The invention relates to a fan (10), in particular an engine cooling fan in a motor vehicle.

Background

Engine fans for motor vehicles are known from the prior art, which have an electric drive with a rotor and a stator, in which engine fans the drive electronics are mounted in an electronics housing, which covers the stator, that is to say the projection plane of the electronics housing on a radial plane arranged perpendicularly to the axis of rotation of the engine fan, covers the projection plane of the stator on this radial plane. This means that the cooling ribs required for cooling the drive electronics are also arranged at the electronics housing outside the projection of the stator on the radial plane. This has the disadvantage that the air drawn in by the fan for cooling the engine is disadvantageously swirled by the cooling ribs. The volume flow of air introduced into the engine compartment is limited by the turbulence thus generated and therefore does not always provide the required cooling power.

Disclosure of Invention

The invention relates in particular to a fan, in particular an engine fan in a motor vehicle, having an electric drive with a rotor, a stator and a control electronics with a substantially flat, radially extending printed circuit board for the control electronics and a substantially fluid-tight electronics housing in which the control electronics are arranged, and a cooling air guide device which is designed to introduce a cooling air flow into the electric drive. It is proposed that the projection area of the stator on the radial plane is larger than the projection area of the electronics housing on the radial plane, wherein the cooling air guide is arranged predominantly in the region of the projection area of the stator, which is not covered by the projection area of the electronics housing.

The advantage of such a fan is that the air drawn in by the fan does not have to flow through or at the cooling air guide, since these are arranged in the projection region. The air provided for cooling flows as laminar as possible, so that a high air volume flow can be transported, which makes it possible to increase the cooling capacity compared to the prior art.

The fan offers the additional advantage over the prior art that, by making the projection surface of the stator on the radial plane larger than the projection surface of the electronics housing on the radial plane, air is also fed into the stator for cooling the control electronics and additionally cools this stator. The electric drive of the fan can therefore be operated at higher power and with higher durability than in the prior art, since this electric drive also operates with a higher cooling power.

Rotors of the type mentioned here rotate about a rotational axis which extends substantially in the axial direction. The axis of rotation may be referred to in this context as an infinitely extending imaginary straight line about which the rotor rotates during operation. Within the scope of the present invention, a radial plane may also refer to an imaginary plane extending substantially perpendicular to the axial direction. Furthermore, within the scope of the invention, the projection plane of the electronics housing or of the stator on the radial plane can refer to a parallel projection or an orthogonal projection of the base plane of the electronics housing or of the stator on the radial plane, wherein the projection beams extend parallel to one another and parallel to the axial direction. The base surface of the electronics housing is here extended by a corresponding side wall of the electronics housing accommodating the control electronics. The base surface of the stator is delimited radially by the outer contour of the pole shoe.

According to the invention, the projection surface of the stator on the radial plane is larger than the projection surface of the electronics housing on the radial plane, so that an area or surface which is not covered by the electronics housing is left between the projection surface of the stator and the projection surface of the electronics housing. This free surface is referred to as the protruding area in the context of the present invention. According to a preferred embodiment of the invention, both the rotor and the stator are of concentric design, in particular rotationally symmetrical with respect to the axis of rotation. According to an advantageous further development of the invention, the drive electronics and therefore the electronics housing accommodating the drive electronics have their center of gravity in the region of the axis of rotation, so that the protruding region has a symmetrical contour with respect to the axis of rotation.

The control electronics have a printed circuit board and electrical components, in particular electrical components of the power electronics. The electrical component is preferably designed as a so-called SMD component or SMD part and is therefore directly fastened to the printed circuit board. In contrast to the components mounted in a straight manner, surface-mounted components of this type are not wired with wires, but are mounted directly on the circuit board by means of a soldering-capable connection surface. The use of SMD components particularly advantageously enables the use of a printed circuit board which is particularly space-and material-saving. According to a particularly advantageous further development of the invention, all electrical components, in particular electrical components of the power electronics, are designed as SMD components and are therefore mounted directly on the printed circuit board. In this way, a particularly space-saving electronics housing with a particularly small base surface can be used, as a result of which the projection area between the projection plane of the stator on the radial plane and the projection plane of the electronics housing on the radial plane can be advantageously maximized and thus the cooling of the electric drive can be maximized.

Within the scope of the present invention, an electronics housing can mean a housing which surrounds the drive electronics in a fluid-tight manner. The housing parts can be parts of an electronics housing, which contribute to the formation of a fluid-tight interior for the control electronics. However, components or housing parts, such as cooling ribs, which are not conducive to sealing the interior space containing the control electronics, cannot therefore be understood as electronics housings according to the invention.

The cooling air guide is arranged predominantly in the extension region, in particular it is intended to mean that at least 75%, preferably at least 90%, particularly preferably at least 95%, of the parallel projection of the base surface of the cooling air guide is arranged in the extension region. Advantageously, the parallel projection of the base surface of the cooling air guide device is arranged completely in the projection region.

Advantageous embodiments and refinements of the features specified in the independent claims are obtained by the measures mentioned in the dependent claims.

The fan or an advantageous further development according to the invention is distinguished in that the electronics housing has at least a first housing element and a second housing element, wherein the control electronics are arranged in the first housing element, and wherein the first housing element has a recess which is covered by the second housing element, wherein the second housing element is preferably designed as a cover for the first housing element. A particularly preferred embodiment of the invention provides that the housing elements are made of aluminum or an aluminum alloy, and that at least one of the housing elements is produced by means of a die-casting process, and that the housing elements are connected to one another in a sealed, in particular fluid-tight manner by means of welding. In the context of the present invention, a die casting process refers to a casting process in which a melt is pressed under high pressure into a permanent mold, wherein the pressure is preferably maintained during hardening. The housing element produced in the die-casting process is preferably made of aluminum, in particular an aluminum alloy, preferably AlSi12(Fe), alloy 230. The first housing element is preferably produced by means of a die-casting process. In addition, the second housing element is particularly preferably produced by means of a molding process. The second housing element is advantageously formed by deep drawing. The starting material for producing the housing element by deep drawing is a wrought alloy which is particularly defect-free and pore-free. The deep drawing allows the production of a defect-free, in particular pore-free, thin-walled, lightweight housing element. It is seen as a further advantage that drawing is a simple and cost-effective process for manufacturing the lid. The housing element drawn from a wrought alloy preferably comprises aluminum, in particular an aluminum alloy, preferably AlMg3, 2 mg0.4. Advantageously, the copper content of the alloy is small, in particular less than 0.3%. Other aluminum alloys can also be used.

According to a preferred embodiment, the fan has a connection housing which comprises a cooling air guide. The connection housing can be produced particularly simply if it is formed in one piece with the first housing element of the electronics housing. Such a one-piece housing element can be produced particularly simply, in particular by the already mentioned die-casting process. The fan housing has a connection housing.

In order to dissipate the waste heat of the electric drive and of the drive electronics which is generated during operation, the fan is designed to convey cooling air into the interior of the electric drive via the fan housing. The fan is designed to supply cooling air to the drive unit, in particular to temperature-critical points, such as the windings and the magnets of the stator. For this purpose, the cooling air guide device has a plurality of cooling ribs according to a particularly preferred embodiment of the invention. Between two adjacent cooling ribs, an air guide gap is also formed, which is perpendicular to the radial plane, i.e. extends in the axial direction.

An advantageous embodiment of the invention also provides that the projection of the stator on the radial plane is configured substantially in the shape of a circle and the projection of the electronics housing on the radial plane is configured in the shape of a polygon, in particular a rectangle, wherein the corner points of the polygonal projection of the electronics housing on the radial plane are arranged in the region of the circumference of the substantially circular projection of the stator on the radial plane. The projection area is thus formed by a circle segment, wherein the partial surface is limited by a circular arc which is spanned by the stator circumference and a circular chord which is formed by the housing edge of the electronics housing.

In this case, the arrangement of the points in the region of the circumference of the projection surface of the stator should mean, in particular, that the points each have a radial distance from the circumference which is less than 20%, preferably less than 10%, particularly preferably less than 15%, of the radius of the circumference.

A rectangular electronics housing of the type described here can be provided in particular in that the printed circuit board has an approximately rectangular contour. Such profiling of the printed circuit board itself can advantageously be provided by using SMD components which have less design structural constraints on the profile of the printed circuit board than conventional electrical components. By using a rectangular printed circuit board and a rectangular electronics housing, the material outlay for the printed circuit board can advantageously be reduced. Since all the electrical components are advantageously arranged as SMD components directly on a rectangular printed circuit board, no installation space to be sealed is required, so that the electronics housing can likewise be designed rectangular with a minimum spacing from the printed circuit board. In this way, the installation space required for the electronics housing can be advantageously reduced and the protruding region can be optimally used for cooling.

In order to provide a uniform spacing of the cooling ribs from one another and consequently an optimum cooling effect, it is provided according to a further advantageous embodiment of the invention that the cooling ribs arranged on one side of the projection surface of the polygon are arranged parallel to one another. In other words, the cooling ribs of the circular segments of the protruding region are preferably arranged substantially parallel to each other, respectively. The cooling ribs here preferably stand vertically on the side edges of the polygonal projection area, that is to say vertically on the circular chord of the respective projection area. The cooling ribs are therefore each arranged orthogonally to a respective housing side of the first housing element of the electronics housing. The cooling ribs, which preferably completely cover the extension region, preferably each have a radial extent which decreases in the direction of an angle point or housing angle of the first housing element of the electronics housing, wherein the free, radial ends of the cooling ribs preferably terminate in a circular arc. One housing side of the first housing element of the electronics housing is preferably arranged between 5 and 15, particularly preferably between 7 and 12 cooling ribs. Providing this number of cooling ribs per housing side achieves an optimum between conditions such as manufacturing, cost, weight and cooling effect.

In order to introduce the cooling air flow into the entire interior space, according to a further particularly preferred embodiment, a main part of the cooling air guide extends radially beyond the circumference of the rotor. If the cooling air guide is formed by cooling ribs, the cooling ribs end in a circular contour, the diameter of which is as large as or larger than the diameter of the rotor.

Since the projecting region between the stator and the electronics housing is not covered by the electronics housing, parts of the stator, such as parts of the windings and pole shoes, are exposed radially, i.e. they are not shielded by adjoining components. In order to protect the stator from foreign bodies and splashes in the projection region and at the same time not to impede or not to impede the cooling effect significantly. According to an embodiment of the invention, a protective device is provided. The protective device is arranged in the region of the cooling air guide device and covers, in a radial plane, primarily the protruding region between the stator and the electronics housing. The projection area is preferably completely covered by the cooling air guide.

Within the scope of the present invention, such a protective device can be understood to mean a device which is a barrier to solid and liquid particles coming from the outside, that is to say which has the ability to protect the interior space of the electric drive or pole housing from the main part of the particles coming from the outside.

In particular, the inner space can be protected particularly simply and at the same time effectively from splashes and dirt particles coming from the outside, i.e. the protective device is essentially designed in the form of a plate, in particular a disk. The protective device extends here as a flat component essentially in the radial direction and thus forms a deflection barrier for the components of the stator. A particularly simple and cost-effective embodiment of the protective device can be provided in that the protective device is formed integrally with the cooling air guide and, as an alternative thereto, or in addition thereto, with the fan housing. Such a one-piece embodiment can preferably be produced particularly simply by means of a corresponding injection molding process. The integrated embodiment of the protective device and the first housing element of the electronics housing particularly advantageously makes it possible to optimally dissipate heat from the printed circuit board itself by providing an additional convection surface, wherein the printed circuit board rests against the first housing element for heat transfer.

For optimum protection of the stator, the protection means is preferably designed as a circular disk. The circular disk preferably has a diameter which corresponds approximately to the diameter of the stator. In this way, the stator can be optimally protected against dirt with a minimum expenditure of material for the protective device.

The protective device is preferably arranged axially centrally in the cooling air guide. With reference to the radial direction, the cooling air guide or the cooling ribs extend beyond the edge of the protection.

In order to optimally fix the fan in the motor vehicle, the fan has a frame. The fan housing is arranged here at the central receiving section. For accommodating the fan, the accommodating section has an accommodating opening. The fan wheel is fixed in a rotationally fixed manner to the rotor so that it rotates together with the rotor about the axis of rotation. An axially extending outflow gap for cooling air is preferably arranged between the fan wheel and the receiving section. The cooling air thus flows into the electric drive via the cooling air guide and flows out of the electric drive via the corresponding outflow gap.

An advantageous further development of the invention provides that a cooling air baffle is arranged along the circumference of the receiving opening of the receiving section of the frame on the side facing away from the fan wheel. This cooling air baffle preferably extends substantially radially and is preferably arranged as a circumferential collar of the receiving section of the frame. The cooling air baffle is preferably constructed integrally with the frame. The cooling air baffle and the protective device are axially offset with respect to one another with reference to the axial direction.

As already mentioned, the two cooling ribs of the cooling air guide device enclose between them one air guide gap each. These air guide gaps are bounded radially on the inside by corresponding housing sides of the electronics housing and on the outside by the receiving openings of the receiving sections of the peripheral frame. In this way, the air guide gaps each form a flow channel for the cooling air. A particularly preferred embodiment of the invention now provides that the cooling air baffle and the protective device, together with the air guide gap, each form a meandering flow channel for the cooling air. The cooling air flowing axially into the electric drive is deflected by the cooling air baffle and the protective device, which extend substantially radially and project into the air guide gap, so that the main flow direction of the cooling air is meandering. According to a preferred embodiment of the invention, the cooling air baffle is arranged at the outer radial edge of the air guide gap and the protective device is arranged at the inner radial edge. The cooling air thus flows into the cooling air guide with a small radius and is then deflected radially outward by the protective device, whereby the flow cross section for the cooling air flow is advantageously enlarged. The convection surface of the protective device can at the same time be optimally used for heat removal by means of this arrangement in the throughflow channel.

In particular, a more optimized flow cross section for the cooling air flow can be provided in that the respective free ends of the radially extending protective device and of the cooling air baffle are arranged in a common radial section, wherein the radial width of the radial section is much smaller than the radial width of the throughflow channel. Both the cooling air baffle and the protective device preferably extend through approximately half of the flow-through channel. The radial section preferably has a radial width which is less than 30%, in particular less than 5%, of the radial width of the flow channel. In other words, the protection device and the cooling air baffle extend radially to about the same diameter.

Drawings

Embodiments of the fan are illustrated in the drawings and are explained in detail in the description that follows. In the figure:

FIG. 1 is a perspective view of a fan;

FIG. 2 is an exploded perspective view of the electric actuator;

fig. 3 shows a section of an embodiment of a fan according to the invention in a perspective exploded view;

FIG. 4 shows a cross section of an embodiment of a fan according to the invention in a sectional view;

fig. 5 is a perspective view of a connection housing with an electronics housing.

Detailed Description

In different embodiment variants, identical parts have the same reference numerals.

Fig. 1 shows a schematic three-dimensional view of a fan 10 according to a first embodiment of the invention. The fan 10 includes a frame 12 for securing the fan 10 at a vehicle. As can be seen clearly in fig. 1, the frame 12 has a through-opening 14 which is preferably circular in shape. A fan wheel 16 is arranged in the region of the through-opening 14. The fan wheel 16 is set into rotation by means of an electric drive 18 and has a plurality of fan wheel blades 20 distributed over the circumference, which are designed for this purpose for conveying cooling air when the fan wheel 16 is rotating. In the central section, the frame 12 has a receiving section 22. According to the embodiment of the invention shown in fig. 1, the receiving section 22 of the edge frame is fastened to the frame 24 of the edge frame 12 by means of struts 25 which overlap the through-openings 14 in the radial direction 32.

As can be seen in fig. 1, the receiving section 22 is of substantially circular design according to the embodiment of the invention shown here and has a central receiving opening 26, in which the electric drive 18 is arranged. According to the embodiment of the invention shown in fig. 1, the electric drive 18 is fastened to the receiving section 22 of the frame 12 and is therefore connected to the motor vehicle by means of the fastening means 30. The receiving opening 26 is configured as a through-opening through the receiving section 22, wherein the electric drive 18 passes through the receiving opening 26 in the axial direction 34.

Fig. 2 shows an exploded perspective view of one embodiment of the electric drive 18. The electric drive 18 has a stator 40 and a rotor 42 as a drive unit. The rotor 42 is arranged on a motor shaft 44 which extends substantially in the axial direction 34.

The electric drive 18 shown in fig. 2 has a brushless structure as an outer rotor. An electrical drive 18 of this type with an external rotor motor is distinguished in that the radially inner part is stationary during operation, while the radially outer part rotates. Windings 48 are arranged on the stator 40 to generate an alternating magnetic field. Magnets 50 moving in a magnetic alternating field are arranged at the circumferential surface of the interior of a substantially pot-shaped pole housing 52 of the rotor 42. The pole housing 52 of the rotor 42 forms a receptacle for the windings 48 and the magnets 50, which are arranged in the pot-shaped pole housing 52.

As can be seen clearly in fig. 2, the stator 40 has a built-in bearing ring 60, from which bearing teeth 62 for receiving the windings 48 extend radially 32 outward in a star-shaped manner. The outer ends of the support teeth 62 each have a pole shoe. The stator 40 is substantially rotationally symmetrical about the axis of rotation of the motor shaft 44 and has a substantially circular base surface. According to the embodiment of the invention shown in fig. 2, the pot-shaped pole housing 52 has a first portion 54 extending in the radial direction 32, which forms the bottom of the pot-shaped pole housing 52. In addition to the first section 54 of the pole housing 52 extending in the radial direction 32, the rotor 42 also has a second section 56 which is arranged at the radial outer edge of the rotor 42 and forms a circumferential cylindrical side wall of the rotor 42. The open region of the rotor 42 opposite the base 54 of the pot-shaped rotor 42 is covered by a fan housing 72, as can be seen clearly in fig. 2. On the side opposite the drive unit, the fan housing 72 has a drive electronics 70 with a substantially flat, radially 32-extending printed circuit board 71 for driving the electric drive 18.

FIG. 3 illustrates another perspective exploded view of a cross-section of an embodiment of the fan 10. As can be seen clearly in fig. 3, the frame 12 has a receiving section 22, in which the electric drive 18 is fastened to the motor vehicle by means of corresponding fastening means 30. The receiving section 22 is substantially annular in shape and, according to the embodiment of the invention shown in fig. 3, has a substantially circular receiving opening 26. Other contours of the receiving opening 26 are of course also conceivable, provided they are suitable for providing a corresponding suspension or fixing of the electric drive 18. When installed, the electric drive 18 with its fan housing 72 is moved into the receiving opening 26 and is fastened to the frame 12 by means of the corresponding fastening means 40.

As can be seen in fig. 3, the pot-shaped pole housing 52 has a circumferential cylindrical side wall 56 which extends substantially in the axial direction 34. For driving the electric drive 18, the fan 10 has drive electronics 70. The control electronics 70 are arranged in an electronics housing 80. The electronics housing 80 has for this purpose a first housing element 82 and a second housing element 84. The control electronics 70 are arranged in a first housing element 82 of the electronics housing. This first housing element has for this purpose a recess into which the drive electronics 70 can be inserted. The first housing member 82 also has a clearance 86. This recess is covered by the second housing element 84. The second housing element 84 is preferably designed as a cover for the first housing element 82. In order to provide a substantially fluid-tight electronics housing 80 for the drive electronics 70 arranged therein, the first housing element 82 and the second housing element 84 are connected to one another substantially fluid-tightly.

According to the embodiment of the invention shown in fig. 3, the second housing element 84 is designed as a cover which, during installation, is arranged on the recess 86 of the first housing element 82 after the drive electronics 70 have been inserted into this recess 86 and completely covers this recess. In this case, in the mounted state, an electronics space remains between the first housing element 82 and the second housing element 84. Such a cover can be produced by drawing of a wrought alloy according to a preferred embodiment of the invention. The cover 13 shown in fig. 3 has a substantially rectangular, flat profile.

The control electronics 70 with the substantially rectangular printed circuit board 71 are arranged in the electronics space and are in particular fastened there before the second housing element 84 is placed on the first housing element 82. According to a further embodiment of the invention, the fastening of the control electronics 70 in the electronics housing 80 is accomplished by fastening elements, in particular contact points, preferably stops at the housing elements 82, 84. After the drive electronics 70 have been inserted into the first housing element 82, the two housing elements 82, 84 are connected to one another in a fluid-tight manner. Such a fluid-tight connection can be provided, for example, in that the two housing elements 82, 84 are welded, preferably laser welded, to one another completely around one another. In particular, a particularly fluid-tight connection can be provided in that at least one further weld seam layer is applied to the first weld seam layer by passing the first weld seam layer over again. Such a multilayer laser weld creates a metallic connection between the two housing elements 82, 84, by means of which good thermal conduction between the two housing elements 82, 84 and thus effective heat removal of the control electronics 70 can be achieved. It is also conceivable for the two housing elements 82, 84 to be connected to one another in a fluid-tight manner by means of electron beam welding or friction stir welding.

As can also be clearly seen in fig. 3, both the electronics housing 80 and the printed circuit board 71 arranged in the electronics housing 80 have a substantially rectangular contour. On the printed circuit board 71, a so-called SMD power electronic component 88 is preferably mounted on the side facing the rotor 42. In contrast to the components mounted in a straight manner, such surface-mounted components 88 do not have wire connections, but rather are soldered directly to the printed circuit board 71 by means of a soldering-capable connection surface. Since the SMD power electronic components 88 are arranged on the side facing away from the housing inner side of the first housing element 82, that is to say on the side of the printed circuit board 71 facing the second housing element 84, the components 88 do not have a direct thermal contact with the electronics housing 80 itself. The printed circuit board 71 contains an arrangement of heat-conducting elements which transfer the heat of the component 88 from the side of the printed circuit board 71 facing away from the rotor 42 to the opposite side of the printed circuit board 71 facing the rotor 42. The side of the printed circuit board 71 facing the rotor 42 is then thermally coupled to the electronics housing 80 or the first housing element 82 of the electronics housing 80 by means of a thermally conductive element, for example by means of a thermally conductive mat or adhesive.

The use of the SMD power electronic components 88 makes it possible to use the printed circuit board 71, which is rectangular in configuration and is particularly space-and material-saving, in a particularly advantageous manner. Since all power electronic components are designed as SMD power electronic components 88 and are therefore mounted directly on the printed circuit board 71, the electronics housing 82 accommodating the printed circuit board 71 is advantageously likewise designed substantially rectangular. The first housing element 82 is thus substantially designed as a box-shaped receptacle for the rectangular printed circuit board 71. The total area of the electronics housing 80 can be reduced in this way based on said integration of electrical and thermal contacts. In this case, the distance between the inner surface of the electronics housing 80 and the printed circuit board 80 arranged in the interior is designed to be as small as possible.

In order to dissipate the waste heat generated during operation of the electric drive 18 and the drive electronics 70, the fan 10 is designed to convey cooling air into the interior of the electric drive 18 via a fan housing 72. The fan 10 is designed in this case to supply cooling air in particular to temperature-critical points of the drive unit, such as the windings 48 and the magnets 52 of the stator 40. For this purpose, the fan has a cooling air guide 90. According to the embodiment of the invention shown in fig. 3, the cooling air guide 90 has a plurality of cooling ribs 92. Between two adjacent cooling ribs 92, which extend substantially along the axis 34, an air guide gap 94 is formed. The inflowing cooling air is thus guided in the axial direction 34 or in the longitudinal direction through the air guide gap 94 into the interior of the electric drive 18.

As can be seen clearly in fig. 3, the fan 10 has a connecting housing 100 which includes cooling ribs 92. The securing device 30 is also preferably configured to be part of the connection housing 100. According to the embodiment of the invention shown in fig. 3, the cooling ribs 92 are arranged on the circumferential side at the electronics housing 80 or at the first housing element 82 of the electronics housing 80. According to a particularly preferred embodiment, the first housing element 82 connecting the housing 100 and the electronics housing 80 is designed in one piece. The fan housing 72 thus includes a first housing member 82 connecting the housing 100 and the electronics housing 80.

In order to ensure high thermal conductivity of the fan housing 72, the fan housing 72 has aluminum as a material. With the one-piece embodiment, the fan housing 72 may be advantageously manufactured cost-effectively in a die-casting process, such as an extrusion process or an injection molding process, together with the cooling ribs 92 or the cooling air guide 90. The mounting of the electric drive 18 to the housing 72 is also facilitated. As can be clearly seen in fig. 3, the cooling ribs 92 extend in the radial direction 32 beyond the circumference of the rotor 42. As already mentioned, the stator 40 is arranged in the interior of the pot-shaped pole housing 52 of the rotor 42.

According to the invention, it is now provided that the projection of the stator 40 onto a radial plane 102, that is to say onto the plane of the printed circuit board 90, is greater than the projection of the electronics housing 80 onto this radial plane 102. In other words, the stator 40 covers a larger radial surface than the base surface of the electronics housing 80, so that a projection region 104 is formed between the smaller electronics housing 80 and the larger stator base surface, which projection region is not covered by the projection surface of the electronics housing 80. In this extension region 104, the cooling air guide 90 is arranged. This relationship is illustrated in detail in fig. 4.

Fig. 4 shows a section through the fan 10 according to the embodiment of the invention shown in fig. 3. As can be seen in fig. 4, the fan 10 has an electric drive 18 with a stator 40 and a rotor 42. The electric drive 18 has a stator 40 and a rotor 42 as a drive unit. The rotor 42 rotates in operation about a motor shaft 44 that extends in the axial direction 34. At the stator 40, windings 48 are arranged for generating an alternating magnetic field. Magnets 50 moving in a magnetic alternating field are arranged on the circumferential surface of the interior of a substantially pot-shaped pole housing 52 of the rotor 42. The pole housing 52 of the rotor 42 forms a receptacle for the windings 48 and the magnets 50.

As already mentioned, the stator 40 has a built-in bearing ring 60, from which bearing teeth 62 for receiving the windings 48 extend radially 32 outward in a star-shaped manner. The outer ends of the support teeth 62 each have a pole shoe. The stator 40 is substantially rotationally symmetrical about the axis of rotation of the motor shaft 44 and has a substantially circular base surface. The open region of the rotor 42 opposite the base 54 of the pot-shaped rotor 42 is covered by a fan housing 72, as can be seen clearly in fig. 4. On the side opposite the drive unit 18, the fan housing 72 has a drive electronics 70 with a substantially flat, radially 32-extending printed circuit board 71 for driving the electric drive 18.

As already mentioned, the fan wheel 16 is set into rotation by means of the electric drive 18 and has a plurality of fan wheel blades 20 distributed over the circumference, which are designed for this purpose for conveying cooling air when the fan wheel 16 is rotating. In order to fix the fan 10 to the motor vehicle, a frame 12 is provided, which has a central receiving section 22. In this case, the fan housing 72 is fastened to the receiving section 22 of the frame 12 by means of corresponding fastening means 30. According to the embodiment of the invention shown in fig. 4, the fastening is accomplished by means of a screw connection, wherein the fan housing has a corresponding receiving bore for the screw connection. The receiving opening 26 is configured as a through-opening through the receiving section 22, wherein the electric drive 18 passes through the receiving opening 26 along an axis 34. The fan housing 72 has a first housing element 82 for receiving the electronics housing 80 of the drive electronics 70.

As can be seen clearly in fig. 4, the first housing element 82 is substantially box-shaped and has a base 106 extending substantially in the radial direction 32 and a side wall 108 extending substantially in the axial direction 34. On the side opposite the base 106, the first housing element 82 has a recess 86. The drive electronics 70 are arranged in a substantially box-shaped first housing element 82. This control electronics has a printed circuit board 71 and an SMD component 88. As can be seen in fig. 4, the printed circuit board 71 is arranged at the bottom 106 of the first housing element. The printed circuit board 71 is preferably mounted for this purpose on the base 106 in a planar manner by means of thermally conductive elements, such as corresponding adhesives. After the drive electronics are installed in the first housing element 82 of the drive electronics 70, the recess 86 is closed in a fluid-tight manner with a corresponding cover (not shown here).

As can be seen clearly in fig. 4, the projection plane 110 of the electronics housing 80 onto the radial plane 102 is a parallel projection of the radially extending base plane of the electronics housing 80 onto the radial plane 102. The base surface of the electronics housing 80 is delimited or widened by the side walls 108. Stator 40 also has a projection plane 112 on radial plane 102, wherein projection plane 112 of stator 40 is a parallel projection of the base plane spanned by stator 40 on radial plane 102. This base surface is delimited by the pole shoes of the carrier teeth 62. As can be seen in fig. 4, a projection area 112 of stator 40 on radial plane 102 is larger than projection area 110 of electronics housing 80. The overhang region 104 is the difference in area in the radial plane 102 between a projection surface 110 of the electronics housing 80 and a projection surface 112 of the stator 40. According to the invention, the cooling air guide 90 is arranged mainly in this extension region 104.

According to the embodiment of the invention shown in fig. 4, the cooling air guide 90 has a plurality of cooling ribs 92. Between two adjacent cooling ribs 92 extending substantially along the axis 34, in each case one air guide gap 94 is formed. The inflowing cooling air is therefore conducted in the axial direction 34 or in the longitudinal direction through the cooling air guide gap 94 into the interior of the electric drive 18.

In order to remove waste heat generated during operation of the electric drive 18 and the drive electronics 70, a cooling air flow is drawn through the cooling air guide 90. The cooling ribs 92 guide the cooling air flow with air guide gaps 94 extending in the axial direction 34. The forced convection cooling air flow can be essentially divided into two main flow paths 122, 124 or circuits as shown in fig. 4. Two main flow paths 122, 124 flow longitudinally through the cooling rib 92.

The first main flow path 122, after exiting the cooling air guide 90, flows through the stator 40 or through the windings 48 in the axial direction 34 and exits the electric drive 18 via the ventilation opening 130 formed in the first section 54 of the pole housing 52 of the rotor 42. In another development, the first main flow path 122 runs between the gap between the fan wheel hubs and the first section 54 of the pole housing 52 and exits the fan 10 through the outflow gap 140. The outflow gap 140 is arranged between the receiving section 22 of the frame 12 and the fan wheel 16 and extends in the axial direction 34, that is to say the first main flow path 122 leads out of the fan 10 essentially in the radial direction 32.

The second main flow path 124, after exiting the air guide 90, exits the electric drive 18 directly between the circumferential cylindrical side wall 56 of the rotor 42 and the cooling ribs 92 and, in the other direction, leaves the fan 10 via the outflow gap 140, likewise like the first main flow path 122.

As can be clearly seen in fig. 4, the fan 10 has a protective device 160. The protection means are arranged in the cooling air guide 90 and extend substantially in the radial direction 32. The guard 160 primarily covers the extension 104. According to the embodiment of the invention shown in fig. 4, the extension area 104 is completely covered by the protective device 160. The protective device 160 shown in fig. 4 is essentially of disc-shaped, in particular disc-shaped, design and forms a barrier for solids and splashes which might otherwise penetrate into the electric drive 18 from the outside. This protective device 160 has proved particularly advantageous in fans of the type described here, in which the stator is no longer completely covered by the electronics housing. As can be seen in fig. 4, the protective device is formed integrally with the cooling air guide 90 or the cooling ribs and the first housing element 82 of the electronics housing 80. According to the embodiment of the invention shown in fig. 4, the protective device 160, which is designed as a circular deflector, has a diameter which corresponds approximately to the diameter of the stator 40, so that the entire stator base surface is covered by the protective device 160 and can therefore be optimally protected from dirt.

As can also be clearly seen in fig. 4, according to the embodiment of the invention shown here, the protective device 160 is arranged approximately centrally in the cooling air guide 90 with reference to the axial direction 34. The protector 160 extends essentially in the radial direction 32, wherein the protector 160 is bent from the radial plane 102 in the direction of the stator 40 by a small angle. According to the embodiment of the invention shown in fig. 4, the protective device 160 is configured substantially as an extension of the base 106 of the first housing element 82, which also extends in the radial direction 34. As can be seen clearly in fig. 4, the printed circuit board 71 rests flat against the base 106 of the first housing element 82, so that the protective device 160, as an extension of the base 106 into the throughflow channel 164, advantageously provides optimum heat dissipation of the printed circuit board 71 by providing an additional convection surface.

As can be seen clearly in fig. 4, at the lower edge of the receiving opening 26 of the receiving section 22 of the frame 12, at the end side facing away from the fan wheel 16, a cooling air baffle plate 162 is arranged. The cooling air baffle 162 likewise extends substantially in the radial direction 32. According to the embodiment of the invention shown in fig. 4, the cooling air baffle 162 is arranged at the circumference of the receiving opening 26 in the sense of a circumferential collar. The cooling air baffle 162 shown in FIG. 4 is constructed integrally with the bezel 12. The cooling air baffle 162 is preferably injection molded (anspriszen) together with the frame 12. As can be seen clearly in fig. 4, the cooling air baffle 162 and the protective device 160 are arranged offset with respect to the axial direction 34, i.e. an axial distance is formed between the cooling air baffle 162 and the protective device 160.

As already mentioned, the two cooling ribs 92 of the cooling air guide 90 sandwich an air guide gap 94 between them. These air guide gaps 94 are bounded radially inwardly by a side wall 108 of the electronics housing 80 extending in the axial direction 34 and outwardly by the receiving opening 26 of the receiving section 22 of the peripheral frame 12. In this way, the air guide gaps 94 form respective flow ducts 164 for the cooling air. As can be seen clearly in fig. 4, the cooling air baffle 162 and the protective device 160 form, together with the air guide gap 94, a meandering flow channel 164 for the cooling air. As can be seen clearly in fig. 4, the cooling air baffle 162 is arranged at the radially outer edge of the air guide gap 94 and the protective device 160 is arranged at the radially inner edge of the air guide gap 94. Both of which extend through approximately half of the flow-through channel 164. The main flow paths 122, 124 for the cooling air flow, based on the cooling air baffle 162 of smaller diameter, flow into the cooling air guide 90 and then are deflected radially outward by the protective device 160, whereby the flow cross section for the cooling air flow is advantageously enlarged. At the same time, the convection surface of the protective device 160 can be optimized for heat removal by this arrangement in the throughflow channel 164.

As can be seen clearly in fig. 4, the protective device extending in the radial direction 32 and the cooling air baffle 162 terminate in a common radial section 166, wherein the radial width of the radial section 166 is much smaller than the radial width of the flow-through channel 164.

Fig. 5 shows the fan housing 72 in a perspective view. Fig. 5 shows the side of the fan housing 72 facing the stator 40. As can be seen clearly in fig. 5, the fan housing 72 has a connection housing 100 which is formed integrally with the first housing element 82 of the electronics housing 80. The connecting housing 100 has a cooling air guide 90 with cooling ribs 92.

As can be seen in fig. 5, the protective device 160 is configured as a circular disk and is arranged within the cooling ribs 92. The cooling ribs each extend in the axial direction 34. Between two adjacent cooling ribs 92, in each case one air guide gap 94 is arranged. As can be seen clearly in fig. 5, the electronics housing 80 or the first housing element 82 of the electronics housing 80 has a rectangular base surface with four corner points 168. The free ends of the cooling ribs 92 terminate in a circular path, wherein the corner points 168 of the rectangular electronics housing 80 lie approximately in this circular path. As can be seen in fig. 5, the cooling ribs 92, which are each arranged on one side of the rectangular electronics housing 80, are arranged as parallel as possible to one another. The cooling ribs 92 are each here standing vertically on the respective housing side.

Claims (17)

1. Fan (10), in particular an engine cooling fan in a motor vehicle, having an electric drive (18) with a rotor (42), a stator (40) and a control electronics (70) with a substantially flat printed circuit board (71) extending in a radial direction (32) for the control electronics (18) and a substantially fluid-tight electronics housing (80) and a cooling air guide (90), in which the control electronics (70) are arranged and which is designed to introduce a cooling air flow (122, 124) into the electric drive (18), characterized in that a projection plane (112) of the stator (40) onto the radial plane (102) is larger than a projection plane (110) of the electronics housing onto the radial plane, wherein the cooling air guide (90) is arranged predominantly in a projecting region (104) of the projection plane (112) of the stator (40), which is not covered by the projection surface (110) of the electronics housing (80).

2. The fan (10) as claimed in claim 1, characterized in that the electronics housing (80) has at least a first housing element (82) and a second housing element (84), wherein the control electronics (70) are arranged in the first housing element (82), and wherein the first housing element (82) has a recess (86) which is covered by the second housing element (84), wherein the second housing element (84) is preferably designed as a cover for the first housing element (82).

3. The fan (10) as claimed in one of the preceding claims, characterized in that the fan (10) comprises a connection housing (100) having the cooling air guide device (90), wherein preferably the connection housing (100) and a first housing element (82) of the electronics housing (80) are constructed in one piece, wherein the fan housing (72) has a connection housing (100) constructed in one piece with the first housing element (82).

4. The fan (10) as claimed in one of the preceding claims, characterized in that the cooling air guide device (90) has a plurality of cooling ribs (92), wherein an air guide gap (94) is formed between two adjacent cooling ribs (92) in each case, said air guide gap extending perpendicularly to the radial plane (102).

5. The fan (10) according to any of the preceding claims, wherein the cooling air guide means (90) extends radially (32) beyond the circumference of the rotor (42).

6. The fan (10) according to any of the preceding claims, wherein a protective device (160) is provided, which is arranged in the cooling air guiding device (90) and substantially covers the protruding area (104) in the radial plane (102).

7. The fan (10) as claimed in one of the preceding claims, characterized in that a projection (112) of the stator (40) onto the radial plane (102) is configured substantially in the shape of a circle and a projection (110) of the electronics housing (80) onto the radial plane (102) is configured in the shape of a polygon, in particular a rectangle, wherein corner points (168) of the polygonal projection (110) of the electronics housing (80) onto the radial plane (102) are preferably arranged in the region of the circumference of the substantially circular projection (112) of the stator (40) onto the radial plane (102).

8. The fan (10) as claimed in one of the preceding claims, characterized in that the cooling ribs (92), which are each arranged on one side of the polygonal projection face (110) of the electronics housing (80), are arranged as parallel as possible to one another and preferably stand vertically on this side of the polygonal projection face (110) of the electronics housing (80).

9. The fan (10) according to one of the preceding claims, characterized in that the protective device (160) is substantially plate-shaped, in particular disc-shaped, wherein the protective device (160) is preferably integrally formed with the cooling air guide device (90) and/or the fan housing (72).

10. The fan (10) according to any of the preceding claims, wherein the protective device (160) is axially offset from the second housing element (84).

11. The fan (10) as claimed in one of the preceding claims, characterized in that a frame (12) is provided for fastening the fan (10) to a motor vehicle, wherein the fan housing (72) is arranged on a central receiving section (22) of the frame (12) having a receiving opening (26), and wherein the fan wheel (16) is arranged on the rotor (42) in a rotationally fixed manner, wherein an outflow gap (140) for cooling air, which extends in the axial direction (34), is arranged between the fan wheel (16) and the receiving section (22).

12. The fan (10) as claimed in one of the preceding claims, characterized in that a cooling air baffle (162) is arranged along the circumference of the receiving opening (26) of the receiving section (22) of the rim (12) on the side facing away from the fan wheel (16), said cooling air baffle extending substantially in the radial direction (32), and in that the cooling air baffle (162) and the protective device (160) are offset from one another in the axial direction.

13. The fan (10) as claimed in one of the preceding claims, characterized in that the air guide gaps (94) are each delimited in the radial direction (32) by a receiving opening (26) of a receiving section (22) of the rim.

14. The fan (10) as claimed in one of the preceding claims, characterized in that the cooling air baffle (162) and the protective device (160) together with the air guide gap (94) each form a meandering flow channel (164) for the cooling air.

15. The fan (10) as claimed in one of the preceding claims, characterized in that the respective free ends of the protective device (160) and of the cooling air baffle (162) which respectively extend in the radial direction (32) are arranged in a common radial section (166), wherein the radial width of the radial section (166) is substantially smaller than the radial width of the throughflow channel (164).

16. The fan (10) of any of the preceding claims, wherein the fan housing (72) is manufactured by a die casting process, a coining process, or a gray casting process.

17. The fan housing (72) as claimed in any of the preceding claims, having a connection housing (100) which is constructed in one piece with the first housing element (82) of the electronics housing (80), wherein the connection housing (100) has the cooling air guide device (90).

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