Fan and mounting plate for a fan

Abstract

A fan, in particular a centrifugal or mixed-flow fan, comprising a motor and an impeller rotationally driven by the motor, wherein the motor or the stator of the motor is fastened to a mounting plate, characterized in that the mounting plate is provided with an aerodynamic functional surface or aerodynamic elements on at least one of its radially outer regions.

Description

[0001] FAN AND MOUNTING PLATE FOR A FAN

[0002] The invention relates to a fan, in particular a radial or diagonal fan, with a motor and an impeller driven by the motor, wherein the motor or the stator of the motor is attached to a support plate.

[0003] Furthermore, the invention relates to a support plate for such a fan.

[0004] Essentially, this is a fan with a mounting plate that serves to attach a motor and impeller. The motor and impeller are typically mounted to a mounting plate of the support structure (support module). While the motor's stator is fixed to the mounting plate, the impeller rotates with the motor's rotor. The mounting plate assembly of the support module, including the motor and impeller, is usually mechanically connected to the nozzle plate, which contains an inlet nozzle, and is thus held in place by the nozzle plate. This connection is typically achieved by struts extending between the mounting plate and the nozzle plate. These struts act as fasteners, separating the nozzle plate from the mounting plate and stabilizing the assembly with the impeller located between them. The presence of these struts allows the assembly of the aforementioned components to be considered a single structural unit.

[0005] For example, in air handling units or data centers, the availability of highly efficient radial or diagonal fans is of particular interest. The latest state of the art for free-running radial impellers is already characterized by free-running, backward-curved radial impellers with very high static impeller efficiencies of > 78%. Guide vanes with profiled support struts are also known, the use of which enables the construction of fans with static efficiencies of up to 84%. However, these are associated with acoustic disadvantages due to the profiled guide struts, especially when low-torque designs with high speeds are required for a specific characteristic curve. In practice, fans with a single support plate and profiled support struts are known for achieving high static efficiencies. For an example of the state of the art, reference is made to DE 10 2020 200 363 A1.

[0006] The invention aims to provide a low-noise and low-rotational-tone fan that is simple in design and assembly. Furthermore, it should differ from competing products.

[0007] Furthermore, a suitable mounting plate for such a fan should be specified.

[0008] The foregoing problem is solved with respect to the fan by the features of claim 1. According to this claim, the generic fan is characterized in that the support plate is equipped with an aerodynamic functional surface or aerodynamic elements on at least one of its radial outer surfaces.

[0009] With regard to the support plate according to the invention, the problem is solved by the features of dependent claim 20.

[0010] Advantageously, the functional surface(s) are formed on the side facing the impeller and / or on the side facing away from the impeller. The radial outer surface of the support plate is designed such that it aerodynamically connects the suction and pressure sides of the support plate in a favorable manner.

[0011] The support plate can have a main flow-guiding area on the side facing the impeller, extending radially outwards and substantially to its outer edge. This area directs the main flow exiting the impeller and near the bottom of the plate radially outwards. Similarly, the support plate can have a reverse flow-guiding area on the side facing away from the impeller, extending radially outwards and substantially to its outer edge. This reverse flow-guiding area deflects any backflow occurring on the side facing away from the impeller radially outwards. From a fluid dynamics perspective, it is further advantageous if the main flow-guiding area and / or the reverse flow-guiding area of ​​the support plate extends from the outer edge of the support plate in the radial direction by at least 5%, preferably at least 10%, of the impeller diameter.It is also conceivable that the main flow-guiding area begins radially inside close to the radially outer edge of the bottom disk of the impeller and carries the air flowing out of the bottom disk during operation of the fan approximately continuously after exiting the bottom disk, and extends in the radial direction, on average over the circumference, by at least 3%, advantageously by 5%, of the bottom disk outlet diameter.

[0012] It is a further advantage if, in the main flow-carrying and backflow-carrying areas, with the exception of the outer edge of the support plate and the areas serving the connection of support struts, there are no or only insignificantly few or local sharp edges, corners or kinks that run clearly perpendicular to the respective flow direction, for example in the circumferential direction.

[0013] As part of a further embodiment, it is conceivable that a recess is formed radially within the main flow-guiding area of ​​the support plate, on the side facing the impeller, which fully or partially accommodates the outer edge of the bottom disk of the impeller in the axial direction.

[0014] Another embodiment provides that the main flow-guiding area of ​​the support plate, on the side facing the impeller, runs obliquely and / or curved in cross-section on a plane through the axis, so that with increasing radius up to the outer edge of the support plate the axially measured distance to the outer edge of the bottom disk of the impeller increases.

[0015] Furthermore, it is advantageous if, in an axial view from the downstream side, the outer edge of the support plate does not radially extend beyond the nozzle plate. Additionally, in an axial view from the downstream side, the outer edge of the support plate can have a radial offset inwards relative to the outer edge of the nozzle plate, for example, by at least 10 mm.

[0016] From a fluid dynamics perspective, it is advantageous if the radial outer surface of the support plate, which defines the radial boundary of the main flow-guiding area and, if applicable, the reverse flow-guiding area, is designed in the manner of a rather thin trailing edge of an impeller blade, preferably with a maximum thickness of 5 mm. Alternatively or additionally, the radial outer surface of the support plate can be designed in the manner of a winglet of an impeller blade.

[0017] It is also conceivable that reinforcing structures, preferably in the form of ribs, honeycombs, or the like, are formed on the side of the support plate facing away from the impeller, preferably in a more radially inner area. The support plate can be attached to support struts, for example, to a nozzle plate of the fan. Advantageously, the support struts do not run parallel to the axis, but rather have a component extending from the nozzle plate to the support plate in the radial direction.

[0018] The support plate is manufactured using a simple, cost-effective process from plastic, in particular from fiber-reinforced thermoplastic materials, preferably by injection molding, or from aluminum, preferably by die casting.

[0019] The support plate according to the invention results from the features of the fan relating to the support plate.

[0020] The essential features of the invention can be summarized from a functional and structural point of view as follows:

[0021] A fan, preferably a radial or diagonal fan, has been developed, comprising a mounting plate to which the motor and its stator are attached. The mounting plate can advantageously be manufactured by casting, for example, aluminum die casting, or by injection molding with a fiber-reinforced thermoplastic. On its radial outer surfaces on the side facing the impeller, it has an aerodynamic functional surface, referred to as the main flow-guiding area of ​​the mounting plate, which, during fan operation, guides the flow exiting radially outwards from the impeller and contributes to increasing the efficiency (especially the static efficiency) of the fan.

[0022] For this purpose, the main flow-guiding surfaces have a specific contour and position, which interacts with the contour of the impeller's base plate. In particular, the main flow-guiding area can be considered, from a fluid dynamics perspective, as a continuation of the base plate, and therefore the offset between the downstream edge of the base plate and the main flow-guiding area is small, for example, less than 10%, advantageously less than 3%, of the impeller diameter. The angular offset between the flow-guiding surface of the base plate at its radially outer edge and the main flow-guiding area at the point of smallest distance between the two areas is also advantageously small, in particular not greater than 10%.

[0023] Ideally, the main flow-guiding region is essentially an approximately continuous and approximately tangent-continuous continuation of the base disk, although a gap between the stationary and rotating parts is unavoidable. The main flow-guiding region may optionally be slightly inclined and / or curved in the radial direction.

[0024] Fulfilling the fluid-flow function of the flow-guiding surface of the impeller's base disc, at least partially, with the stationary, main flow-guiding area offers advantages. Fluid friction on the stationary part (unlike the rotating part) does not require any drive power and therefore does not result in any efficiency losses. The stationary part also has lower static requirements and does not need to be balanced, which allows for the use of more cost-effective materials and manufacturing processes. Furthermore, this reduces the impeller's weight, as the surface area of ​​the impeller's base disc can be made smaller, thus relieving stress on components such as motor bearings.

[0025] In an advantageous embodiment, the support plate also has an aerodynamic functional surface, referred to as the backflow-guiding area of ​​the support plate, on its radial outer edges on the side facing away from the impeller. During fan operation, this area guides and redirects a regularly occurring backflow, which flows towards the support plate in a central flow region on the side facing away from the impeller, radially outwards, thus contributing to an increase in the efficiency (especially the static efficiency) of the fan. The backflow-guiding area extends to a radial outer edge of the support plate. It is designed to be aerodynamically efficient with respect to a radially oriented flow on the rear side of the support plate facing away from the impeller, for example, being largely smooth, flat, or slightly curved, or provided with ribs or elongated structures that are predominantly radially oriented.In particular, the backflow-guiding area does not contain any ribs, folds, edges, corners, projections or the like that extend predominantly circumferentially or over large areas in the circumferential direction and would significantly disturb a flow that is predominantly radially oriented.

[0026] The radial outer edge of the support plate, at the radially outer end of the main flow-guiding area and, if applicable, also of the backflow-guiding area, can be considered a trailing edge in this respect. It can, for example, be designed to be rather thin, similar to the trailing edge of a wing.

[0027] Particularly in embodiments with a backflow-guiding area on the side of the support plate facing away from the impeller, the design of the radial outer area of ​​the support plate can be analogous to a winglet, which aerodynamically connects the suction and pressure sides of an aerodynamically effective body. For example, a local curvature of the flow-guiding surfaces towards the side facing away from the impeller can be incorporated in the radial outer area of ​​the support plate. On the rear side facing away from the impeller, reinforcing structures are advantageously placed in a more radially inward area. These structures can be easily integrated into a casting, for example, in the form of ribs or honeycomb structures, to increase the strength and stiffness against deformation of the support plate.

[0028] In advantageous embodiments manufactured using plastic injection molding, reinforcing elements such as metal inserts, organosheets or continuous fiber-reinforced elements, e.g., tapes that can be unwound from a spool, can be integrated into the casting to meet the special strength requirements of such a support plate, while still having a particularly resource-efficient and cost-effective design.

[0029] It is particularly advantageous for the impeller to be axially embedded in the support plate, for which purpose the support plate can have a recess in the area of ​​the bottom disc of the impeller.

[0030] Advantageously, provisions for guiding or allowing a cooling airflow for the drive motor are provided on the inside of the support plate, in the area of ​​the motor connection. The pressure difference between the inner side of the support plate facing the impeller and the outer side facing away from the impeller can thus be used naturally to support motor cooling.

[0031] Advantageously, cooling passages for the passage of a cooling airflow for the drive motor can also be integrated in or on the drive motor itself as a result of a pressure difference between the inside facing the impeller and the outside facing away from the impeller. This allows the cooling air to pass through the motor or through components of the motor.

[0032] Metal support struts, or those with metallic reinforcement, are advantageous for connecting the support plate to the nozzle plate. These metal struts can have a round cross-section, or be grooved circumferentially, have a polygonal or star-shaped cross-section, and are advantageously manufactured as extruded profiles.

[0033] The struts can run parallel to the fan axis or, advantageously, not parallel to the fan axis, but rather from the outside inwards, from the nozzle plate towards the support plate.

[0034] The support struts can be embedded in the base plate during the casting process. Alternatively, they can be glued into corresponding recesses in the base plate or screwed in place using a dowel-like action. The support struts can also be threaded rods to which the base plate is screwed.

[0035] The support struts may have provisions at their ends facing the support plate for bolting the plate to it, e.g., screw flanges. Spacers may be fitted around the support struts.

[0036] An interface for mounting the motor is provided on the inside of the mounting plate. Advantageously, provisions for motor cooling are also provided in this area. In particular, a design is provided in which, when assembled, openings or channels are formed through which a cooling airflow flows from the rear side of the mounting plate (away from the impeller), past the motor and / or through parts of the motor, to the side of the mounting plate facing the impeller, thereby creating pressure differences due to fan operation. The design of these cooling provisions can be implemented in a variety of ways. The stator flange of an external rotor motor can be adapted accordingly, for example, by incorporating cooling airflow passages through the stator flange, perhaps in the axial direction.

[0037] The nozzle plate can be made of sheet metal or cast iron.

[0038] There are now various ways to advantageously develop and further refine the teaching of the present invention. For this purpose, reference is made, on the one hand, to the claims subordinate to claim 1 and, on the other hand, to the following explanation of preferred embodiments of a fan according to the invention with a support plate according to the invention, with reference to the drawing. In conjunction with the explanation of the preferred embodiments of the invention with reference to the drawing, generally preferred embodiments and further developments of the teaching are also explained. The drawing shows:

[0039] Fig. 1 shows an embodiment of a fan according to the invention in perspective view from the outflow side, with a support plate according to the invention that is aerodynamically effective on both sides.

[0040] Fig. 2 shows a perspective view of the fan as seen from the inflow side, according to Fig. 1.

[0041] Fig. 3 shows a side view of the fan from Figs. 1 and 2.

[0042] Fig. 4 shows the fan from Figs. 1 to 3 in a view in a direction parallel to the axis of rotation and seen from the outflow side.

[0043] Fig. 5 shows a side view of the fan as seen in Figures 1 to 4, in a section at a plane through the axis.

[0044] Fig. 6 shows a perspective view from the outflow side and a section in a plane through the axis of the fan according to Figures 1 to 5.

[0045] Fig. 7, in a perspective view viewed primarily from the downstream side, is a schematic representation of the flow in the downstream area of ​​a fan according to the invention, similar to that shown in Figs. 1 to 6, generated from simulation data, with streamlines shown on a section plane through the fan axis. Fig. 8, in a perspective view viewed from the downstream side, shows a further embodiment of a fan according to the invention with a support plate according to the invention, aerodynamically effective on both sides, with axially parallel support struts.

[0046] Fig. 9 shows a perspective view of the fan as seen from the inflow side, according to Fig. 8.

[0047] Fig. 10 shows a side view of the fan from Figs. 8 and 9, and

[0048] Fig. 11 shows the fan from Figs. 8 to 10 in a view in a direction parallel to the axis of rotation and seen from the outflow side.

[0049] Figure 1 shows, in a perspective view primarily from the downstream side, an embodiment of a fan 29 according to the invention with a support plate 6, which here is designed as a cast part. The support plate 6 is part of the support module 1, which also includes the support struts 8 that are attached to the support plate 6. The support module 1 serves to attach the motor 4 with the impeller 3 attached to it to the nozzle plate 5.

[0050] Mounting devices 17 are provided on the nozzle plate 5 for attaching the fan 29 to the higher-level air handling system, building, or plant. Thus, the motor 4 and the impeller 3 are indirectly attached to the higher-level air handling system, building, or plant via the support module 1.

[0051] The inlet nozzle 2 is centrally mounted on the nozzle plate 5. It can be manufactured as a separate component, advantageously by injection molding, and connected to the nozzle plate by means of fastening devices 49, or it can be manufactured integrally as a single piece with the nozzle plate 5, for example, by a deep-drawing process. During operation of the fan 29, the impeller 3, attached to the rotor 23 of the motor 4, rotates about the axis of rotation (see Fig. 2), also commonly referred to as the axis, driven by the motor 4. During operation of the fan 29, a conveyed medium, usually air, is drawn into the impeller 3 through the inlet nozzle 2 and an inner opening in the cover plate 19. The impeller 3 consists in particular of the cover plate 19, the bottom plate 9, and the circumferentially distributed blades 18 extending between them, and is conveyed radially outwards between the blades 18.The conveyed medium then exits radially outwards from the impeller 3 and continues to flow radially between the support plate 6 and the nozzle plate 5 before, after passing the struts 8, it exits radially outwards from the fan 29.

[0052] As the fluid flows through the impeller 3, the power supplied by the motor 4 is transferred to the pumped medium, which therefore experiences a total pressure increase. In turn, waste heat is inevitably generated at the motor 4, which must be dissipated; in other words, the motor 4 must be cooled.

[0053] A fan 29 is provided for use in a higher-level system, be it an air handling system, device, or building. Specific examples include, among many others, air handling units, data center cooling systems, and ventilation systems. It was observed that downstream of the fan 29, on the side of the support plate 6 facing away from the impeller 3, a backflow towards the fan 29 or towards the support plate 6 occurs at a significant axial distance, rather centrally and close to the axis, extending radially outwards, for example, roughly to the outer edge 33 of the support plate 6 or slightly beyond (see Fig. 7 with description).

[0054] The support plate 6 is now suitable for redirecting this backflow favorably, namely radially outwards. For this purpose, a backflow-guiding area 27 is formed in the outer area 7 on the side of the support plate 6 facing away from the impeller 3. This area may optionally also be formed from several circumferentially divided sub-areas. The backflow-guiding area 27 is designed to be aerodynamically favorable with respect to a backflow that is to be directed approximately radially outwards. It extends radially over at least 3%, preferably 6%, of the largest diameter of the support plate 6 with respect to the axis, up to an outer edge 33 of the support plate 6. This area can, for example, be partially flat or slightly curved and largely smooth.There are no substantially circumferential flow obstructions such as circumferentially extending ribs, corners, projections, edges, folds or the like, so that the flow in this area can flow unhindered in the radial direction up to the outer edge 33 of the support plate 6.

[0055] The outer edge 33 is advantageously designed to be rather thin or tapered to a point, so that the flow can escape unhindered.

[0056] Possible ribs or other structures in the backflow-guiding area 27 are, in a projection onto a plane perpendicular to the axis (according to the view of Fig. 4), oriented rather in the radial direction or slightly inclined or curved to it, in order to minimize their flow resistance with respect to a predominantly radially directed flow.

[0057] The four support struts 8 here are designed to be compact and slim in order to minimize acoustic interactions with the flow exiting the impeller 3.

[0058] Advantageously, the support struts 8 are manufactured as extruded profiles. The support struts 8 are connected to the support plate 6 at connection points 26. They can advantageously be cast into the casting.

[0059] In other embodiments, metallic connecting elements may also be cast in, with which the struts 8 are then connected, e.g. by screwing, clipping, shrinking, pressing in or welding.

[0060] Struts 8 can also be glued or welded into the casting, i.e., the support plate 6. Struts 8 can also be screwed directly to the casting; for example, threads are formed on the struts, allowing them to be screwed to the support plate 6 with nuts.

[0061] It is also conceivable to use embodiments in which screws are screwed into the end face of support struts shaped as suitable extruded profiles, through which the support struts 8 are widened like a dowel and clamp firmly to the support plate 6.

[0062] In the support plate 6, force introduction areas 13 are formed in the vicinity of the connection provisions 26 for the support struts 8 with the support plate 6. These force introduction areas 13, here designed as ribs, are also essentially oriented in the radial direction and extend relatively little in the circumferential direction; for example, they extend (calculated in total over the entire circumference) at approximately the radius of the support strut connection provisions 26 by less than 25% of the total circumferential extent of the support plate 6, in order not to impair the deflection of the backflow in the radial direction too much.

[0063] A suitable and effective deflection of the return flow in a radial direction, as well as the most loss-free possible merging of this return flow with the main flow exiting the fan, as achieved by the design of the support plate 6 with the return flow-guiding areas 27, which are formed in the outer area 7 of the support plate 6, as well as the outer edge 33 of the support plate 6 and its design, is particularly advantageous for the air performance, the efficiency and the low noise level of the fan 29 in operation.

[0064] In the radially inner region 31 of the support plate 6, particularly radially within the backflow-guiding region 27, reinforced structures, here in the form of reinforcing ribs 16, are formed. In this region, such ribs can also extend circumferentially or, for example, form a honeycomb or fan pattern. These reinforcing structures 16 increase the stiffness of the support plate 6 in order to ensure sufficiently low deflections or deformations of the support plate 6, particularly during operation of the fan 29.

[0065] The motor 4, with its stator 24, is attached to suitable fastening devices 39 in an inner area of ​​the support plate 6, for example by screws. Advantageously, adequately sized washers or cast-in or inserted metal bushings are used for screwing.

[0066] The fan 29 can be installed or attached to a higher-level system. Advantageously, the fan 29, with its nozzle plate 5, is attached to a higher-level system, for example, an air handling unit or a cooling unit, such as for a data center. For this purpose, the nozzle plate 5 is provided with mounting provisions 17, for example, in the form of holes for screws or rivets.

[0067] The nozzle plate 5 advantageously has a folded edge 22 on its outer surface, where the sheet metal of the nozzle plate 5 is folded over, advantageously towards the impeller 3. The folded edge 22 improves the dimensional stability of the nozzle plate 5, the aerodynamic stability properties of the fan 29, and also provides some protection against the potentially sharp outer edge of the nozzle plate 5. An axial folded edge height of the folded edge 22 of 3% to 8% of the largest diameter of the impeller 3 has proven ideal.

[0068] In Fig. 2, the fan 29 according to Fig. 1 is shown in a perspective view, primarily from the inflow side. In this view, the main flow-guiding area 28 is clearly visible in the radial outer area 7 of the support plate 6, on the side of the support plate 6 facing the impeller 3. It is located on the opposite side of the outer area 7 of the support plate 6 from the return flow-guiding area 27 (see Fig. 5). The main flow exiting the impeller 3 during operation flows past the main flow-guiding area 28, thereby directing this main flow radially beyond the base plate 9 of the impeller 3. This, in particular, increases the efficiency of the fan 29.It can be seen that the impeller 3 with its base disk 9 and especially with its radially outer edge 10 is arranged very close to the main flow-guiding area 28 of the side of the support plate 6 facing the impeller 3, so that the flow guidance of the flow near the base disk can be continued after exiting radially outside the base disk 9 to its radially outer edge 10 directly from the main flow-guiding surface 28 in the outer area 7 of the support plate 6.

[0069] In the illustrated embodiment, the impeller 3, with its base disk 9, or in particular its radially outer edge 10, is even slightly recessed axially into the support plate 6, so that an almost continuous guide surface for the flow near the base disk is provided from the base disk 9 of the impeller 3 to the radially outer end 33 of the support plate 6. For this purpose, the support plate 6 has a recess 11 in a region opposite the base disk (see Fig. 5).

[0070] The radially outer edge 33 of the support plate 6 has, viewed in the circumferential direction, different sections 20 and 21. The sections 20 (side regions 20) are rather flat or almost straight and correspond to the sides of the nozzle plate 5. The sections 21 (corner regions 21) are rather rounded here, but can also be straight. They correspond more closely to the corners of the nozzle plate 5; however, these corners of the support plate 6 are not formed as fully defined corners at its outer edge 33, but are instead formed by a rounding or chamfer in the shape of the corner regions 21 (see Fig. 4).

[0071] The connection of the struts 8 with the support plate 6 at the connection areas 26 corresponds, at least predominantly, to the corner areas 21.

[0072] In the exemplary embodiment, four support struts 8 are formed. Other numbers of support struts 8 can also be formed, for example eight or twelve.

[0073] Figure 3 shows a side view of the fan 29 from Figures 1 and 2. In the illustrated embodiment, the inclined, non-axial orientation of the support struts 8 is clearly visible. This design reduces critical transverse vibration modes. The fan 29 has a very compact axial design.

[0074] In one embodiment, the support struts can be 8 threaded rods which are screwed to the support plate 6 and the nozzle plate 5 with nuts.

[0075] The support struts 8 are connected to the support plate 8 at the connection areas 26, and to the nozzle plate 5 at the connection areas 25.

[0076] If the support struts 8 do not run parallel to the axis, i.e., not perpendicular to the nozzle plate 5, which regularly runs approximately along a plane perpendicular to the axis, special measures and shims may be necessary in the connection area 25 between the nozzle plate 5 and the support struts 8. A similar situation may arise with the connection between the support struts 8 and the support plate 6 in the connection area 26.

[0077] Therefore, it may be advantageous to bend or design support struts 8 that run predominantly at an angle to the axis in such a way that they run locally approximately parallel to the axis in a connection area 25 to the nozzle plate 5 and, if necessary, in a connection area 26 to the support plate 6.

[0078] In Fig. 3 it is also clearly visible that, in the exemplary embodiment, the main flow-guiding area 28 runs at a slight angle to an imaginary plane perpendicular to the axis on the outer surface 7 of the support plate 6, and is also slightly curved. The contour of the main flow-guiding area 28 is essentially a planar extension of the inner surface of the base plate 9 facing the wings 18, or at least forms, together with the inner surface of the base plate 9, a common unit that guides the main flow and deflects it primarily in the radial direction.

[0079] For manufacturing reasons, as well as for aerodynamic or aeroacoustic reasons, it can be advantageous if the support struts 8 meet the main flow-guiding area 28 locally at approximately a perpendicular angle, or at least at an angle of approximately 5°. Figure 4 shows the fan 29 from Figures 1 to 3 in a view parallel to the axis from the rear, i.e., from the downstream side. The division of the downstream side of the support plate 6 into a radially outer area 7 with the backflow-guiding areas 27 and a radially inner area 31 with numerous stiffening structures or ribs 16, some of which also run transversely to the radial direction in the inner area 31, is clearly visible.

[0080] Within the interior, the motor 4 with its stator 24 is attached to the connecting devices 39, i.e. the support plate 6 supports the motor 4 and the impeller 3 attached to its rotor 23.

[0081] In the assembled state shown, cooling air channels 14 are formed in the connection area of ​​the motor 4 or its stator 24 to the mounting plate 6. In the assembled state, the cooling air channels 14 pass through the mounting plate 6, whereby the stator 24 itself, or parts thereof, can also partially form the boundary of the cooling air channels 14, depending on the embodiment. The cooling air inlets into the channels 14 can be seen radially outside the motor. As a result of the pressure differences created by the operation of the fan 29 between the inner side of the support plate 6 facing the impeller 3 and the outer side facing away from the impeller 3, which is visible in Fig. 4, cooling air is drawn into the cooling flow inlets on the outer side and directed to the inner side, where it subsequently contributes to motor cooling, as it is guided close to the motor, and / or is directed to the cooling fins 47 of the stator 24 of the motor 4 (see Fig. 5, 6), and / or possiblyis routed through motor 4 or components thereof.

[0082] If the motor 4 itself has a cooling flow channel that connects the stator side facing away from the impeller with the rotor side facing the impeller through the support plate 6, then, in an advantageous embodiment, the cooling fluid is guided directly through the cooling channels integrated into the motor due to the design with the support plate 6 and the pressure differences that arise during operation, thus ensuring very good heat dissipation from the motor. In this exemplary embodiment, the radial extent of the support plate 6 up to its outer edge 33 is similar to the radial extent of the nozzle plate 5 and, in particular, does not extend significantly beyond it radially.

[0083] The support plate 6 has chamfered or rounded corner areas 21 along its outer edge 33. Such a design has proven particularly advantageous in an installation situation of the fan 29 where the fan is connected on the pressure side to a duct with an approximately rectangular cross-section, or where several fans are arranged and operated in parallel, next to and above each other.

[0084] The support plate 6 has, along its outer edge 33, side regions 20 that run rather straight and parallel to the corresponding edges 12 of the nozzle plate 5. In such a design, it is particularly ensured that, with maximized radial extent of the support plate 6, the support plate 6 with its outer edge 33 does not project beyond the nozzle plate 5 in the radial direction.

[0085] Fig. 5 shows a section of the fan 29 according to Figs. 1 to 4 in a plane through the fan axis and viewed from the side. For clarity, the motor 4 with its stator 24 and rotor 23 is not shown in section. The particularly compact axial design is achieved in this embodiment by the casting of the support plate 6 in combination with the design of the impeller 3. The motor 4 occupies an axial space which it shares with the impeller 3 and the support plate 6; in particular, it is arranged axially in a conically shaped inner area on the side of the base plate 9 facing away from the blades 18. The mounting plane of the motor 4 on the support plate 6 for attaching the motor 4 or its stator 24 to its stator flange 46 can be precisely adjusted by the design of the support plate 6 so that the motor 4 is positioned axially in an ideally adapted position.

[0086] It is conceivable that different motors could be used for the otherwise identical or similar fan, requiring the interior of the mounting plate to be adapted accordingly. This can be advantageously achieved using interchangeable inserts in a casting tool for the mounting plate, and similarly for the impeller or its base plate.

[0087] The cooling air channels 14, which are formed on the support plate 6 in combination with the motor 4 or its stator 24, are clearly visible in Fig. 5. In fan operation, they direct a cooling airflow from the outside, i.e., the side of the support plate 6 facing away from the impeller 3, to the inside, i.e., the side of the support plate 6 facing the impeller 3, towards the cooling fins 47 of the stator 24 of the motor, before finally exiting at the radially outer end 10 of the cover plate 9 between the impeller 3 and the support plate 6 and mixing with the main flow.

[0088] Heat is efficiently dissipated from the cooling fins 47, which in the exemplary embodiment are formed on the stator flange 46 of the stator 24, advantageously with the aid of a cooling fan wheel 48 which rotates relative to the cooling fins 47 and which is attached to the rotor 23 of the motor 4.

[0089] In the exemplary embodiment, the motor 4 also has a cooling fan wheel 48 on the rotor side, which assists the cooling airflow passing through the cooling channels 14. Depending on requirements, design and application, this cooling fan wheel, which can also generate noise and requires drive power, can be omitted.

[0090] The rotor 23 of the motor 4 or the rotor bell 45 protrudes into the flow area into the interior of the impeller 3, which is additionally advantageous for optimal cooling of the motor 4.

[0091] The motor 4 is attached to the support plate 6 of the support module 1 by its stator 24. The impeller 3, in turn, is attached to the rotor 23 of the motor 4, which is mounted on the stator 24. Thus, the impeller 3 is also indirectly held to the support module 1, or rather the support plate 6, via the motor 4. The support module 1, and in particular the support plate 6, is therefore advantageously designed to be particularly dimensionally stable (rigid), for example, to avoid increased vibration levels that can occur during operation, or to prevent the impeller 3 from rubbing against the inlet nozzle 2 due to unwanted deformations during operation. This is because, in the area of ​​the radial gap 44, only a small distance is formed between the inlet nozzle 2 and the cover plate 19 of the impeller 3 in order to achieve high efficiency of the fan 29.

[0092] The maximum radial extent of the support plate is typically 1.2 to 1.4 times the outer diameter of the cover plate of the impeller 3.

[0093] In addition to the design of the impeller 3, the design and arrangement of the support plate 6 has proven to be particularly important for achieving maximum efficiency.

[0094] Figure 5 shows more clearly than the previous illustrations that the inlet nozzle 2 projects into a central opening in the cover plate 19 of the impeller 3, so that the incoming fluid flows through the inlet nozzle 2 into the impeller 3 during operation. The inlet nozzle 2 forms a radial gap 44 with the surrounding cover plate 19, and it must be ensured that no gap can form between the cover plate 19 and the inlet nozzle 2 during operation. This necessitates a sufficiently dimensionally stable and rigid design of the support module 1 and, in particular, the support plate 6, so that the impeller 3 with the motor 4 is mounted via the struts 8 and the support plate 6 in a largely fixed relative position to the nozzle plate 5 and the inlet nozzle 2, respectively.

[0095] The impeller 3 is connected to the rotor 23 of the motor 4; this is done by fastening devices 50, not explicitly shown here, which can be designed in a variety of ways; in particular, the impeller 3 can be screwed to the rotor 23 of the motor 4.

[0096] In the exemplary embodiment, the rotating cooling fan wheel 48 is arranged in an inner area between the support plate 6 and the base plate 9, which provides good shielding of the sound caused by the cooling fan wheel 48 during operation against radiation, so that this sound does not disturb anyone or contributes little or nothing to the sound power of the fan 29.

[0097] Advantageous embodiments are also conceivable in which a cooling fan wheel can be dispensed with, thus eliminating the need for its drive power. In this case, the motor 4 is sufficiently cooled, in particular, by the air flowing through the cooling channels 14 or directly through the motor or its components.

[0098] A particularly advantageous motor cooling can be achieved through the cooling channels 14, through which a flow is induced as a result of pressure differences generated by the fan 29 during operation, which promotes the cooling effect.

[0099] The support struts 8, which run at an angle to the axis, can advantageously be manufactured as meter-long sections, for example, using extrusion, and can be cut to suitable lengths for mounting a support module 1. Thus, meter-long sections of support struts 8 can be used flexibly for support modules 1 with different strut lengths, simply by cutting them to the appropriate length. Therefore, support modules for various wheels, for example, can be manufactured using a single extrusion die for struts.

[0100] In the embodiment shown in Fig. 5, the support struts 8 are straight and run at an angle to the axis.

[0101] It can be advantageous if the support struts have curves or bends. In particular, it is advantageous if support struts are shaped so that, even if they do not have an overall axially parallel course, they meet the respective connected plate approximately perpendicularly at least in the connection area 25 with the nozzle plate 5 and / or in the connection area 26 with the support plate 8, as this facilitates the connection and, due to simpler connection design, can also indirectly have a positive effect on the efficiency and acoustics of the fan.

[0102] Fig. 6 shows a section through the fan axis and a perspective view from behind of the fan 29 according to Figs. 1 to 5, whereby the motor 4 with its stator 24 and its rotor 23 is not shown in section for clarity. From a different perspective, one can see what is described in particular in Fig. 5. However, the advantageous design of the support plate 6 of this embodiment is particularly evident in this illustration at its radially outer region 7. On the support plate 6, in a radially outer region 7, flow-guiding surfaces 28 and 27 are formed on both the inner side facing the impeller 3 and the outer side facing away from the impeller. These surfaces, taken together, favorably influence the flow pattern in such a way that the efficiency is maximized and the noise emission is minimized.On the side of the outer surface 7 facing the impeller 3, the main flow-guiding area 28 is formed, which directs the main flow exiting the impeller 3 radially outwards to the radially outer edge 10 of the base plate 9. On the side of the outer surface 7 facing away from the impeller 3, the reverse flow-guiding area 27 is formed, which directs and redirects the reverse flow occurring on the side of the support plate 6 facing away from the impeller 3 radially outwards.

[0103] The flow direction at the support plate 6 is always predominantly "from radially inside to radially outside," both on the inner and outer surfaces. The radial outer edge 33 of the support plate 6 is therefore analogous to the trailing edge of an airfoil, acting as a trailing edge. Accordingly, this radial outer edge 33 of the support plate 6 is advantageously designed to be thin.

[0104] In cross-section, the contours of the backflow-leading area 27 and the main flow-leading area 28 run approximately parallel to each other near the outer edge 33, except for a small angle of less than 15° where they may converge towards the outer edge 33 of the support plate 6.

[0105] Figure 7 shows a schematic, perspective view derived from a flow simulation, illustrating a flow pattern derived from a flow simulation. This flow pattern is a time-averaged image taken at a cross-section of a plane through the fan axis. The flow pattern was obtained by simulating an embodiment comparable to those shown in Figures 1 to 6, where the fan 29 and its position are schematically sketched. Streamlines 15 are visible, schematically indicating the flow path and representing the approximate paths of flow particles.

[0106] In the area of ​​the support plate 6, which is schematically represented as a grid model, the main flow 36 flows radially from the inside out on the side facing the impeller 3. In the main flow-guiding area 28 on the side of the outer surface 7 of the support plate 6 facing the impeller 3, this main flow is directed radially outwards and advantageously guided, so that the static efficiency of the fan 29 can be increased.

[0107] In the area of ​​the support plate 6, which is schematically represented as a grid model, the return flow 37 flows radially from the inside to the outside on the side facing away from the impeller 3 in the exemplary embodiment. In the return flow-guiding area 27 on the side of the outer surface 7 of the support plate 6 facing away from the impeller 3, this return flow is redirected radially outwards and advantageously guided so that the static efficiency of the fan 29 can be increased.

[0108] At the radially outer edge 33 of the support plate 6, the main flow 36 and the reverse flow 37 meet and continue to flow radially outwards alongside each other without separation. Due to the coordinated design of the main flow-carrying area 28 and the reverse flow-carrying area 27, no turbulence or other adverse flow conditions occur when the two flows meet. The two flows behave harmoniously towards each other, which is advantageous for the static efficiency, the air flow rate, and the low noise level of the fan 29.

[0109] Due to the advantageously thin design of the radial outer edge 33 of the support plate 6, where the main flow-guiding area 28 and the reverse flow-guiding area 27 meet, no large wake dimple is formed, and the two flows 36 and 37, the main flow 36 and the reverse flow 37, flow smoothly parallel to each other after the radial outer edge 33, which is advantageous for the static efficiency, the air flow rate, and the low noise level of the fan 29. Fig. 8 shows, in a perspective view from the downstream side, a further embodiment of a fan 29 with an embodiment of a support module 1 with a support plate 6 according to the invention, wherein the support plate 6 has a flow-guiding area 28 facing the impeller 3 (see Fig. 9) and a motor connection area with fastening provisions 39 for attaching a motor 4 or a motor 4.its stator 24 is integrally manufactured in a casting process, preferably in plastic injection molding.

[0110] The possibility of manufacturing the support plate in aluminum die-casting for similar embodiments should also be explicitly mentioned.

[0111] One difference compared to the embodiment shown in Figures 1 to 6, which is similar in many features, is that the straight support struts 8 run parallel to the axis. This can have advantages, particularly with regard to the connection of the support struts 8 to the nozzle plate 5 and / or the support plate 6. It can also be simpler to achieve comparable support modules 1 with different axial heights (e.g., for different impellers of comparable outer diameter) simply by cutting the required support struts to different lengths.

[0112] In the exemplary embodiment, a direction-of-rotation arrow 30 for the operation of the impeller 3 of the fan 29 is shown on the component of the nozzle plate 5. The impeller 3 is a backward-curved impeller of radial or diagonal design, and the blades 18 of the impeller 3 are inclined backwards in their course from radially inward to radially outward, opposite to the direction of rotation.

[0113] In the exemplary embodiment, the nozzle plate 5 is manufactured in plastic injection molding, wherein the inlet nozzle 2 is integrated in one piece into the nozzle plate 5.

[0114] In the exemplary embodiment, stiffening structures 42 are provided on the side of the injection-molded nozzle plate 5 facing the impeller 3, here in the form of a honeycomb structure. On the back side of the nozzle plate 5, these can extend to its radially outer edge because there is no flow-guiding area on the side of the nozzle plate facing the impeller 3.

[0115] The nozzle plate 5 has fastening provisions 17 for attaching the fan 29 to a higher-level structure or an air handling system or the like.

[0116] In the exemplary embodiment, the nozzle plate 5 has no defined corners on its radially outer edge 12, but is rather rounded or chamfered in the corner region 38. The side regions 34 of the outer edge 12 of the nozzle plate 2 run approximately straight between the corner regions 38.

[0117] In the exemplary embodiment, the motor 4, which is held on the support plate 6, does not project axially beyond the support plate 6 on the side facing away from the impeller 3, but rather ends axially flush with the support plate 6. The connection provisions 39 for connecting the stator 24 of the motor 4 to the support plate 6 are located on the support plate 6.

[0118] In the exemplary embodiment, the support plate 6 has a recess 41 through which connecting cables for the motor 4 can be routed.

[0119] In this embodiment, no cooling channels are formed on the support plate 6. Instead, internal cooling channels are integrated into the motor 4. Air, as the cooling medium within the motor 4, or at least components thereof, passes through the support plate 6 due to the pressure difference that arises between the two sides of the support plate 6 during fan operation, thus cooling the motor 4. In Fig. 8, a corresponding inlet opening 43 for cooling air is visible on the stator 24 of the motor 4 in this embodiment.

[0120] Fig. 9 shows a perspective view of the fan 29 according to Fig. 8, viewed primarily from the inflow side. The outlet openings 40 for the cooling air passing through the motor 4 during operation can be seen on the rotor housing 45 or the rotor 23 of the motor 4. As described with reference to Fig. 8, this cooling air enters the motor 4, specifically its stator 24, on the side of the support plate 6 facing away from the impeller 3 during operation of the fan 29, due to pressure differences built up by the fan 29. In this embodiment, the cooling air duct extends into the intake area of ​​the impeller 3, which can be advantageous because a particularly low pressure ratio prevails there during operation, thus generating even more cooling airflow.

[0121] The support struts 8 run parallel to the axis. Several specific designs for the construction of the support struts 8 are conceivable.

[0122] In one embodiment, the support struts 8 can be threaded rods or long screws, which, in an advantageous embodiment, can also be surrounded by sleeve-like elements in the outflow area opposite the flow outlet from the impeller 3. These sleeves then serve as spacers. They can be metal sleeves or plastic sleeves with any advantageously flow-optimized cross-sectional shape, which may even be integrated in one piece into a cast support plate 6 and / or nozzle plate 5.

[0123] Extruded profiles with any cross-section are also possible, advantageously designed with aerodynamic optimization.

[0124] In an advantageous embodiment, support struts 8 formed as extruded profiles can also be designed with a polygonal or star-shaped cross-sectional contour in order to improve or facilitate the connection with support plate 6 and / or nozzle plate 5.

[0125] In Fig. 9, the design of a main flow-guiding area 28 in the outer area 7 of the support plate 6, radially outside the outer edge 10 of the cover plate 9 of the impeller 3, is again clearly visible. From a fluid dynamics perspective, and advantageously at least approximately from a geometric contour perspective, the main flow-guiding area 28 forms, in particular, a radial continuation of the inner contour of the base plate 9. Fig. 10 shows a side view of the fan from Figs. 8 and 9. The axially parallel course of the support struts 8 implemented in this embodiment is visible.

[0126] In the exemplary embodiment, the radial extent of the support plate 6 is smaller than that of the nozzle plate 5 (see Fig. 11).

[0127] The cover plate 19 has a strongly curved profile at its radially outer end, pointing towards the nozzle plate 5. This is advantageous for achieving a high efficiency.

[0128] The exit width is the maximum axial distance between the radially outer edge 10 of the bottom disk 9 and the radially outer edge of the cover disk 19, each measured on the inner contour facing the wings 18.

[0129] The fan 29 exhibits a very compact axial design. The motor and mounting plate 6 together protrude axially only less than half the outlet width beyond the outer edge 10 of the base plate 9.

[0130] The fan 29 exhibits a very compact axial design. The maximum overall axial extent of the fan, including motor 4 and nozzle plate 5, is less than 2.5 times the outlet width.

[0131] In Fig. 11, the fan 29 from Figs. 8 to 10 is shown in a view in a direction parallel to the axis of rotation and seen from the outflow side.

[0132] To achieve the required dimensional stability of the support plate 6 without producing excessively thick walls for the casting process, stiffening features 16 are advantageously formed on the outer surface of cast support plates 6, facing away from the impeller 3, predominantly in a radial inner region 31 of the support plate 6. In the exemplary embodiment, these are ribs or webs of varying orientations and a suitable axial height relative to the base wall, e.g., 15 mm to 50 mm, extending from a base wall, which reinforce the support plate 6 as required. In a further inner region of the outer surface of the support plate 6 facing away from the impeller 3, namely near the connection to the stator 24 of the motor 4 with the connection features 39, no ribs or webs are formed in the exemplary embodiment. Here, the stator 24 connected there assumes the mechanical reinforcing function.

[0133] In this view from the downstream side, the backflow-guiding area 27 is clearly visible in a radially outer region 7 of the support plate 6. This area extends to the outer edge 33 of the support plate 6 and has only a few ribs. These are primarily the ribs 16 in the force application area 13 of the connection device 26 for attaching the support struts 8, which, however, are predominantly oriented radially or do not have a significant circumferential extent.

[0134] As can be clearly seen in Fig. 11, the support plate 6 has a smaller radial extent at its outer edge 33 than the nozzle plate 2. This can be advantageous when installing the fan 29 in a higher-level system, because the fan 29 can then be inserted into a suitable opening in the higher-level device and connected to the device by means of the fastening provisions 17 on the nozzle plate 2.

[0135] In the exemplary embodiment, the backflow-guiding region 27 is somewhat narrower in the radial direction than in the exemplary embodiment according to Figs. 1 to 6. On average over the circumference, however, it is sufficiently pronounced and has a mean radial extent of over 5%, advantageously over 10%, of the outer diameter of the impeller 3 at its cover plate 19.

[0136] In the exemplary embodiment, the ribs 16 are radially oriented in the central region, which means that this region can also be considered part of the backflow-guiding area, since this region is also aerodynamically optimized with regard to flow over the surface, primarily in the radial direction. However, a certain kink is formed in the base wall at the radial end of the inner region 31 (see Fig. 8), which is why this region was not considered part of the backflow-guiding area. Other forms of integrated stiffening measures on a cast support plate 6 are also conceivable, e.g., advantageously, vertically extending ribs, fan-shaped structures, honeycomb structures, etc.

[0137] Regarding further advantageous embodiments of the fan according to the invention and the support plate of the fan, reference is made to the general part of the description and to the attached claims to avoid repetition.

[0138] Finally, it should be expressly pointed out that the exemplary embodiments of the fan and support plate according to the invention described above serve only to illustrate the claimed teaching, but do not limit it to these exemplary embodiments.

[0139] Reference symbol list

[0140]

Claims

Claims 1. Fan, in particular radial or diagonal fan, with a motor and an impeller driven by the motor, wherein the motor or the stator of the motor is attached to a support plate, characterized in that the support plate is equipped on at least one of its radial outer surfaces with an aerodynamic functional surface or aerodynamic elements.

2. Fan according to claim 1, characterized in that the functional surface^) is / are formed on the side facing the impeller and / or on the side facing away from the impeller.

3. Fan according to claim 1 or 2, characterized in that the radial outer surface of the support plate is designed in such a way as to connect the suction and pressure sides of the support plate in an aerodynamically favorable manner.

4. Fan according to one of claims 1 to 3, characterized in that the support plate has a main flow guiding area in a radially outer region and extending substantially to its radially outer edge on the side facing the impeller, which guides the main flow exiting the impeller and near the bottom disk radially outwards.

5. Fan according to one of claims 1 to 4, characterized in that the support plate has a backflow-guiding area in a radially outer region and extending substantially to its radially outer edge on the side facing away from the impeller, which deflects a backflow occurring on the side facing away from the impeller radially outwards.

6. Fan according to one of claims 1 to 5, characterized in that the main flow-guiding area and / or the return flow-guiding area of ​​the support plate extends from the outer edge of the support plate approximately in a radial direction. The tung extends or extend by at least 5%, preferably by at least 10%, of the impeller diameter.

7. Fan according to one of claims 1 to 6, characterized in that the main flow-guiding area begins radially inside close to the radially outer edge of the bottom disk of the impeller and carries the air flowing out of the bottom disk during operation of the fan approximately continuously after exiting the bottom disk, and extends in the radial direction, on average over the circumference, by at least 3%, advantageously by 5%, of the bottom disk outlet diameter.

8. Fan according to one of claims 1 to 7, characterized in that in the main flow-guiding and in the backflow-guiding area, with the exception of the outer edge of the support plate and the areas serving for the connection of support struts, no or only insignificantly few or local sharp edges, corners or kinks are formed which run clearly transversely to the respective flow direction, for example in the circumferential direction.

9. Fan according to one of claims 1 to 8, characterized in that a recess is formed radially within the main flow-guiding area of ​​the support plate on the side facing the impeller, which receives the outer edge of the bottom disk of the impeller in the axial direction completely or partially.

10. Fan according to one of claims 1 to 9, characterized in that the main flow-guiding area of ​​the support plate, on the side facing the impeller, is inclined and / or curved in section on a plane through the axis, so that with increasing radius up to the outer edge of the support plate the axially measured distance to the outer edge of the bottom disk of the impeller increases.

11. Fan according to one of claims 1 to 10, characterized in that, in an axially parallel view seen from the downstream side, the support plate does not radially project beyond the nozzle plate with its outer edge.

12. Fan according to one of claim 11, characterized in that, in an axially parallel view viewed from the outflow side, the outer edge of the support plate has a radial offset inwards to the outer edge of the nozzle plate over the circumference, e.g. by at least 10 mm.

13. Fan according to one of claims 1 to 12, characterized in that the radial outer surface of the support plate, which defines the main flow-guiding area and, if applicable, the return flow-guiding area radially outwards, is designed in the sense of a rather thin trailing edge of a blade of the impeller, preferably with a thickness of a maximum of 5 mm.

14. Fan according to one of claims 1 to 13, characterized in that the radial outer surface of the support plate is designed in the sense of a winglet of a blade of the impeller.

15. Fan according to one of claims 1 to 14, characterized in that reinforcing structures are formed on the side of the support plate facing away from the impeller, preferably in a rather radially inner area, preferably in the form of ribs, honeycombs or the like.

16. Fan according to one of claims 1 to 15, characterized in that the support plate is attached with support struts, for example to a nozzle plate of the fan.

17. Fan according to claim 16, characterized in that the support struts do not run parallel to the axis, but have a component extending from the outside to the inside in the radial direction from the nozzle plate to the support plate.

18. Fan according to one of claims 1 to 17, characterized in that the support plate is made of plastic, in particular of fiber-reinforced thermoplastic plastics, preferably by injection molding, or of aluminum, preferably by die casting.

19. Fan according to one of claims 1 to 18, characterized in that in an inner area of ​​the support plate in the vicinity of the connection interface for the motor, inwards open or closed channels are formed which form cooling air channels in the assembled state of the fan.

20. Support plate for a fan with the features relating to the support plate according to any one of claims 1 to 19.

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