Fan and cooling structure for a fan

Abstract

The invention relates to a fan with an impeller and an electric motor, wherein the electric motor comprises a rotor, a stator and possibly an electronics pot and the impeller comprises an impeller hub, wherein a cooling structure is formed or arranged radially outside the outer wall of the rotor and radially outside the outer wall of the stator and / or the electronics pot, which cooling structure forms a flow path for a fluid, preferably for air, by way of which a flow is induced as a consequence of a pressure difference generated by the operation of the fan, which flow dissipates heat from the electric motor, from the rotor, from the stator and / or from the electronics pot. Moreover, the invention relates to a corresponding cooling structure for a fan.

Description

[0001] FAN AND COOLING STRUCTURE FOR A FAN

[0002] The invention relates to a fan with an impeller and an electric motor, wherein the electric motor comprises a rotor, a stator and optionally an electronics housing, and the impeller comprises an impeller hub, wherein a cooling structure is formed or arranged radially outside the outer wall of the rotor and radially outside the outer wall of the stator and / or the electronics housing, which forms a flow path for a fluid, preferably air, through which a flow is induced as a result of a pressure difference generated by the operation of the fan, which dissipates heat from the electric motor, the rotor, the stator and / or the electronics housing.

[0003] Furthermore, the invention relates to a cooling structure for a fan.

[0004] Fans of the type in question have been known in practice for years. For example, reference is made to DE 102022 210 553 A1.

[0005] Fans are regularly subjected to high thermal stresses. This is especially true when the fan is used to circulate a fluid at an elevated temperature, such as hot air from a heat exchanger. These temperatures negatively impact the fan's operation. In particular, the electronic components within the integrated circuit (in EC fans) and other components such as bearings, insulation materials, winding wires, etc., are subject to certain temperature limits that restrict the fan's performance and / or speed. Excessive temperatures lead to damage to these components.

[0006] The state of the art already offers approaches to avoid the aforementioned overheating problems. For example, EC external rotor motors with integrated electronics are already being equipped with integrated cooling. This requires a redesign of the motor. Hubs with openings or recesses, which reduce efficiency, are also available. These improve airflow around the motor. Furthermore, cooling systems with openings in the stator flange are already known from practical experience, although these also require a redesign of the motors or stators. Additional components for directing cooling air to or around the motor also exist. These are structurally complex and not very efficient.

[0007] DE 10 2022 210 555 A1 discloses a fan with an impeller and an electric motor, the electric motor comprising a stator and a rotor. A cooling flow channel is formed between the radial outer wall of the stator and a cooling structure, creating an airflow path between the inlet and outlet sides of the fan. A pressure difference generated by the operation of the fan induces a flow against the main flow direction through this flow path, which carries heat away from the electric motor and / or the stator.

[0008] Although the previously described measures offer valuable cooling options, heat dissipation in a fan or its individual components is insufficient, especially at elevated fluid temperatures. Consequently, as the fluid temperature increases, the power consumption and thus the fan speed must be reduced to prevent critical temperature limits from being exceeded. This means the motors' full power capacity cannot be utilized, as the individual components reach their temperature limits before the electric motor's maximum power output.

[0009] The present invention therefore aims to design and further develop a fan and a cooling structure for a fan of the type mentioned above in such a way as to enable improved heat dissipation in the fan. Furthermore, the fan should differ from competing fans and offer a wider performance range than conventional fans.

[0010] The aforementioned problem is solved with respect to the fan according to the invention by the features of claim 1. According to this claim, the fan in question comprises an impeller and an electric motor, wherein the electric motor comprises a rotor, a stator, and optionally an electronics housing, and the impeller comprises an impeller hub. A cooling structure is formed or arranged radially outside the outer wall of the rotor and radially outside the outer wall of the stator and / or the electronics housing, forming a flow path for a fluid, preferably air. A flow is induced through this flow path by a pressure difference generated by the operation of the fan, which dissipates heat from the electric motor, the rotor, the stator, and / or the electronics housing.

[0011] Furthermore, the aforementioned problem with regard to the cooling structure is solved by the features of dependent claim 13. The cooling structure in question relates to a cooling structure for a fan with an impeller comprising an impeller hub and an electric motor comprising a rotor, a stator and optionally an electronics housing, in particular with the features relating to the cooling structure according to any one of claims 1 to 12. The cooling structure is formed or arranged between the impeller hub and the stator and between the impeller hub and the rotor.

[0012] In accordance with the invention, it has first been recognized that improved heat dissipation is made possible by cleverly designing a cooling structure radially outside the outer wall of the rotor and radially outside the outer wall of the stator and / or the electronic housing.

[0013] Specifically, the cooling structure is designed such that a fluid flow path is formed radially outside the outer wall of the rotor and radially outside the outer wall of the stator and / or the electronics housing. A pressure difference generated by the operation of the fan induces a flow through this path, which dissipates heat from the electric motor, the stator, and / or the electronics housing.

[0014] The pressure differential is created by the cooling structure on the outer wall of the rotor and the outer wall of the stator such that the flow in the axial direction of the fan is directed from the pressure side to the suction side of the fan, opposite to the main volume flow of the fan. This passively driven flow surrounds the fan, in particular the rotor and / or the electric motor, preferably the stator and / or the electronics housing, thereby dissipating heat from the individual components of the fan. The cooling structure is preferably designed in two parts, in particular an inlet-side cooling structure part, which, viewed in the axial direction of the fan, is formed or arranged in the region of the rotor on the inlet side of the fan, and an outflow-side cooling structure part, which is formed or arranged in the region of the stator.

[0015] One of the advantages achieved through further development is better utilization of the permissible temperature limits, thereby increasing the fan's efficiency. This enables higher volume flows and / or greater pressure increases. Overall, the fan according to the invention expands the potential range of applications, particularly with regard to conveying fluids with elevated temperatures.

[0016] Consequently, the fan according to the invention is a fan that is designed and further developed in such a way as to enable improved heat dissipation. Furthermore, the fan differs from competing fans and enables a wider performance range than conventional fans.

[0017] The term "cooling structure" is to be understood in the broadest sense and generally describes a structure or element suitable for dissipating heat from a component and thus regulating the temperature of the component and / or a higher-level system, in particular preventing overheating. Cooling structures can include, in particular, thermally conductive elements, measures for increasing surface area, and / or structures for flow through and / or around the component. Preferably, a cooling structure in the sense of the invention is a structure for flow through and / or around the electric motor, in particular the stator and, if applicable, the electronic housing, for active heat dissipation.

[0018] In an advantageous embodiment, the cooling structure forms at least one cooling flow channel between the outer wall of the rotor and an inner surface of the impeller hub facing the outer wall of the rotor. The cooling flow channel preferably has a cylindrical cross-sectional area. By forming a cooling flow channel, the flow is separated from the main volume flow of the fan. Furthermore, the flow is guided in the axial direction along the outer wall of the rotor for essentially its entire length. One of the advantages achieved with this further development is improved heat dissipation in the fan according to the invention.

[0019] In one embodiment of the fan according to the invention, at least one flow constriction is formed in the cooling flow channel in the flow path between the outer wall of the stator and / or the electronic housing and the cooling structure, and / or between the outer wall of the rotor and the cooling structure. The flow constriction directs the flow at high velocity close to the outer wall of the rotor. In the flow path upstream of the constriction, this causes a stagnation of the flow, resulting in an acceleration of the flow in the region of the constriction. The resulting turbulent eddies in the flow increase the heat transfer from the rotor to the fluid. One of the associated advantages is improved heat dissipation in the fan according to the invention.

[0020] According to an advantageous embodiment of the invention, the electric motor comprises at least one mounting device, in particular a stator flange and / or rotor flange, for mounting the electric motor on a higher-level structure and / or for mounting the impeller on the rotor, wherein the mounting device is at least partially located in the flow path. The mounting device preferably extends radially outwards from the outer wall of the rotor and / or stator or electronic housing, with the mounting provision projecting at least partially into the flow path of the fluid flowing along the outer wall of the electric motor. In addition to its load-bearing function, the mounting device also has a cooling function by dissipating heat from the electric motor, in particular from the rotor and / or stator or electronic housing. The heat is transferred to the fluid by the fluid flowing around or through the mounting device.One of the advantages achieved through further training is therefore improved heat dissipation in the fan according to the invention.

[0021] Advantageously, the mounting device comprises at least one cooling passage, wherein the cooling passage is designed to direct the flow from an inlet side of the fan to an outlet side of the fan (or vice versa). A cooling passage is preferably designed as a recess in a plane of the mounting device extending radially outwards from the outer wall of the rotor and / or stator or electronic housing, so that the mounting device, which is arranged in the fluid flow path, is permeable to the fluid. One of the associated advantages is improved heat dissipation.

[0022] In a preferred embodiment, the mounting device comprises at least one cooling element, in particular a cooling fin, wherein the cooling element is at least partially formed or arranged on and / or within the cooling passage. This results in a larger heat transfer surface area on the mounting device. Furthermore, by arranging the cooling element in the flow path, a disruptive element is introduced, which causes turbulence. One of the associated advantages is a more efficient heat transfer from the mounting device to the fluid and consequently improved heat dissipation.

[0023] Furthermore, it is advantageous if at least one cooling element, preferably an axially extending cooling fin, is formed or arranged on the outer wall of the stator and / or the electronic housing. This creates a larger heat transfer surface, which enables improved heat dissipation.

[0024] In an advantageous embodiment, the impeller comprises an impeller hub with an opening for guiding the flow. In particular, the impeller hub includes a fluid-optimized hub cap, which is formed or arranged at the free end of the impeller hub on the inflow side, and wherein the hub cap separates the flow induced by the pressure difference from the main volume flow of the fan. One of the advantages achieved thereby is controlled flow guidance and thus improved heat transfer.

[0025] Furthermore, it is advantageous if the cooling structure is not formed by or passes through functionally essential components of the engine. The cooling structure according to the invention can be implemented in a variety of ways. The essential point is that the flow path does not pass through functionally essential components of the engine. Without the cooling structure, such an engine is fully functional, but with reduced cooling capacity. Accordingly, the cooling structure can be retrofitted. For this purpose, the cooling structure can be integrated into a separate component.

[0026] In one embodiment of the fan according to the invention, the cooling structure is at least partially formed or arranged on a motor mounting plate of a radial or diagonal fan, or integrated into a mounting plate. Accordingly, at least part of the cooling structure can be retrofitted, preferably as a separate component.

[0027] In an advantageous embodiment, the fan comprises a guide vane with a guide wheel, wherein the guide vane serves as a support for the motor. Advantageously, at least part of the cooling structure is formed by the guide vane, in particular by a hub ring. One of the advantages achieved with this further development is thus improved heat dissipation in the fan according to the invention. In addition, the cooling structure is at least partially retrofittable.

[0028] The cooling structure according to the invention for a fan comprising an impeller with an impeller hub and an electric motor comprising a rotor, a stator, and optionally an electronics housing, particularly with the features relating to the cooling structure according to any one of claims 1 to 12, is designed such that the cooling structure is at least partially formed or arranged between the impeller hub and the rotor. There are now various ways to advantageously design and further develop 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 a preferred embodiment of the invention with reference to the drawing. In conjunction with the explanation of the preferred embodiment of the invention with reference to the drawing, generally preferred embodiments and further developments of the teaching are also explained. The drawing shows

[0029] Fig. 1 shows a perspective view from the outflow side of a fan with a cooling structure according to the invention;

[0030] Fig. 2 shows a perspective view from the inflow side of the fan according to Fig. 1;

[0031] Fig. 3 shows a side view and a section in a plane through the axis of the fan according to Figs. 1 and 2;

[0032] Fig. 4 shows a perspective view and a section in a plane through the axis of the fan according to Figs. 1 to 3 from the outflow side;

[0033] Fig. 5 shows a front view from the outflow side of the fan according to Figs. 1 to 4;

[0034] Fig. 6 shows a rear view from the inflow side of the fan according to Figs. 1 to 5;

[0035] Fig. 7a shows a perspective view from the inflow side of a stator for the fan according to Fig. 1;

[0036] Fig. 7b shows a front view of the stator from the inflow side according to Fig. Fig. 7c in a perspective view and in section at a plane through the axis of the stator according to Fig. 7a and 7b;

[0037] Fig. 8a shows a perspective view from the inflow side of a rotor for the fan according to Fig. 1;

[0038] Fig. 8b shows a side view of the rotor according to Fig. 8a; and

[0039] Fig. 8c in a perspective view and in section at a plane through the axis of the rotor according to Fig. 8a and 8b;

[0040] Fig. 1 shows a perspective view from the outflow side of a fan 1 of axial design with an embodiment of a cooling structure 25 according to the invention.

[0041] The fan comprises a guide vane unit 2. This consists in particular of a housing 3, an intermediate ring 4, a hub ring 5, inner guide vanes 6 extending between hub ring 5 and intermediate ring 4, and strut vanes 8 extending between intermediate ring 4 and housing 3 or its diffuser area 7. The guide vane unit 2 is advantageously manufactured in one piece using a casting process, preferably plastic injection molding.

[0042] The housing 3 defines the outer boundary of the fan flow (main volume flow) within the housing 3. The housing 3 consists of various sections, initially an inlet nozzle 9 in the direction of flow, then an advantageously cylindrical section within which the impeller 10 with its blades 11 is arranged, and a diffuser section 7 to which the strut blades 8 are attached. Downstream of the impeller 10 within the housing 3, an internal guide vane is arranged, consisting in particular of aerodynamically effective internal guide vanes 6 extending between the hub ring 5 and the intermediate ring 4. As a result of the aerodynamic effect of the internal guide vanes 6 in conjunction with the intermediate ring 4 and the hub ring 5, the static efficiency and the air performance, especially the static pressure increase at a given delivery volume flow, of the fan 1 are particularly high.On the hub ring 5, radially within the stator-side receiving area 12, also called hub pot, the motor 13 with its stator 14 is attached to a flange, which also serves as a motor mounting flange 16, so that the inner guide vanes 6 and the intermediate ring 4 also have a supporting function for the motor 13 and ultimately also the impeller 10.

[0043] To hold the motor 13 with the impeller 10 and the inner guide vane to the outer housing 3, the outer strut wings 8 are formed. These have only a subordinate aerodynamic function and primarily serve to attach the inner guide vane, and thus the motor 13 and the impeller 10, to the outer housing 3. They are designed to minimize noise, so that their presence during operation of the fan 1 generates little or no additional noise. Within the housing 3, in the axial region of the diffuser 7, in the span direction (i.e., from hub ring 5 to diffuser 7), two distinct flow zones are formed: an outer flow zone 17 between the intermediate ring 4 and the diffuser wall 7 of the housing 3, and an inner flow zone 18 between the hub ring 5 and the intermediate ring 4.

[0044] The inner flow area 18 includes the supporting inner guide elements 6, which have a fluid-technical function and, for example, reduce flow swirl, cause a build-up of static pressure, avoid or reduce hub backflow and generate little noise due to their radially inner position.

[0045] The outer flow area 17 comprises the load-bearing strut wings 8, six in the exemplary embodiment, advantageously four to eight, distributed around the circumference, which are designed to be noise-optimized. Flanges are integrally formed on the inlet and outlet sides of the guide unit 2 at the edge regions of the housing 3, which advantageously have various mounting provisions 19, 20. Mounting provisions 19 are provided on the inlet-side flange for attaching the guide unit 2, and thus the fan 1, to a higher-level device or system, just as mounting provisions 20 are provided on the outlet-side flange for attaching the guide unit 2 to a higher-level device or system.

[0046] Furthermore, mounting provisions 21 for a protective grille are provided on the downstream flange; similar provisions can also be provided on the upstream flange. The protective grilles can be countersunk and screwed onto the area so that they do not protrude axially beyond the guide vane 2, resulting in good handling and stackability of the fans 1.

[0047] The intermediate ring 4 has a wavy edge on its downstream side and can also be serrated or slotted. However, it can also be circular without any waviness.

[0048] Within the hub ring 5 in the stator-side mounting area 12, the motor 13 is arranged on the guide unit 2 on an integrally integrated motor mounting flange 16. To stiffen and stabilize the connection with the motor 13, stiffening ribs 22 are also provided within the stator-side mounting area 12. In particular, provisions for improving motor heat dissipation are provided in the stator-side mounting area 12.

[0049] The fan 1 shown has a cooling structure 25. During operation of the fan 1, a cooling flow passes through the cooling structure 25, which carries away an additional heat flow from the motor 13, in particular from the rotor 15 and the stator 14 or the electronics housing. In this embodiment, the cooling structure 25 is formed from two sections: an outflow-side section 25a and an inflow-side section 25b.

[0050] In the exemplary embodiment, the downstream part of the cooling structure 25a consists of the hub ring 5 and the elements integrally mounted radially within it, in particular a stator flange 26, here also designed as a motor mounting flange. The downstream part of the cooling structure 25a forms a cylindrical downstream cooling flow channel 27a with the outer wall of the stator 43, through which the cooling flow enters the fan 1 due to the pressure difference between the downstream and inflow sides.

[0051] The stator 14 of the motor 13, which in this embodiment is an external rotor motor, in particular an EC motor preferably with integrated motor electronics, is visible. The motor electronics are integrated into the stator 14 within a housing. This housing can also be attached to the stator 14 as a separate component. The cooling structure 25 promotes the dissipation of heat from the stator 14 of the motor 13 and, in this embodiment, particularly from its housing. This improves the cooling of the electronic components, allowing the motor 13 to deliver higher torques and thus higher power outputs at the same ambient or conveying medium temperature.

[0052] Sufficient radial space is available between the outer contour of the stator 14 and the electronics housing due to the design of the downstream part of the cooling structure 25 with the hub ring 5 in the hub housing at the stator-side end. This is advantageous and allows for easy connection of the required electrical cables to the stator 14 and the electronics housing of the motor 13 during assembly.

[0053] Fig. 2 shows a perspective view of the fan 1 according to Fig. 1, as seen from the inflow side. In addition to and supplementing Fig. 1, the impeller 10 with its blades 11 integrally attached to an impeller hub 28 can be seen.

[0054] The hub of the impeller 28 is open at the end face on the inflow side. The interior of the impeller hub 28 forms a rotor-side receiving area 29 in which the rotor 15 of the motor 13 is received.

[0055] In the exemplary embodiment, the inlet-side part of the cooling structure 25b is formed by the impeller hub 28. The inlet-side part of the cooling structure 25b, together with the outer wall of the rotor 44, forms a cylindrical inlet-side cooling flow channel 27b through which the cooling flow exits the fan 1 at the inlet-side end.

[0056] Several fastening devices 30 for attaching a hydrodynamically optimized hub cap (not shown) are arranged on the end face in the direction of rotation. In the hub area of ​​the impeller 10, the hub cap, in conjunction with the impeller hub 28, ensures a hydrodynamically optimized contour, which is advantageous for high efficiency and low noise levels. The hub cap has a substantially circular opening in a radially inner area. This design of the hub cap ensures that the cooling flow can escape from the inlet-side cooling channel 27b. During operation of the fan 1, the impeller 10, driven by the rotor 15 of the motor 13 to which it is attached, rotates in the direction of rotation 31, approximately clockwise in this embodiment.

[0057] This causes the fan 1 to convey a conveyed medium, in particular air, from the inlet side visible here, in the direction of flow through the axial sections inlet nozzle 9, impeller section 29, and diffuser 7 to the outlet side axially opposite the inlet side. In particular, energy is transferred to the conveyed medium flow, which can be measured as a pressure increase, especially a total pressure increase and / or an increase in static pressure. Downstream of the impeller 10, the conveyed medium flow splits into two main components: one that flows through the outer flow section 17 and a second that flows through the inner flow section 18.

[0058] Fig. 3 shows a side view and a section in a plane through the axis of the fan 1 according to Figs. 1 and 2 from the outflow side. In addition to the preceding descriptions, Fig. 3 shows the complete flow path formed by the cooling structure 25 inside the fan 1.

[0059] The motor 13, consisting of stator 14 and rotor 15, is shown schematically. The stator 14 is attached inside the stator-side receiving area 12 by means of a stator flange 26, which also functions as a motor mounting flange 16. The impeller 10, with its hub 28 and blades 11, the radially outer ends of which advantageously have a special contour, so-called winglets 33, is attached to the rotor 15 of the motor 13 by means of a rotor flange 34, whereby a small radial gap is formed between the impeller blades 11 with the winglets 33 and the impeller area 32 of the housing 3, and a flow gap is present.

[0060] On the downstream side, the cooling structure 25 is formed by the hub ring 5. This downstream portion of the cooling structure 25a forms a downstream cooling flow channel 27a with the outer wall of the stator 14, which is received in the stator-side receiving area within the hub ring 12. This channel geometrically limits the flow path of the cooling flow. On the upstream side, the cooling structure 25 is formed by the impeller hub 28. This upstream portion of the cooling structure 25b forms a downstream cooling flow channel 27b with the outer wall of the rotor 15, which is received in the rotor-side receiving area within the impeller hub 28. This channel geometrically limits the flow path of the cooling flow in this section. The two sections of the cooling channel 27 are fluidically connected. In the exemplary embodiment, the stator flange 26 has a plurality of cooling passages 35 distributed around the circumference of the stator flange 26 (see Fig. 7a to 7c).Furthermore, the rotor flange 34 is recessed except for the areas where fastening provisions 36 for attaching the impeller 10 to the rotor 15 are formed (see Figs. 8a to 8c). This creates a flow-related connection between the inlet side and the outlet side of the fan 1.

[0061] Fig. 4 shows in a perspective view and in section on a plane through the axis the fan 1 according to Figs. 1 to 3 from the outflow side.

[0062] Fig. 5 shows an axial top view of the fan 1 from the downstream side, as shown in Figs. 1 to 4. The downstream part of the cooling structure 25a, which is integrated here into a supporting guide vane 2, is clearly visible. In addition to the preceding descriptions, the outer flow area 17, traversed by the strut blades 8, and the inner flow area 18 with the inner guide vanes 6 are clearly visible. During operation of the fan 1, the impeller 10 with the blades 11 rotates in the direction of rotation 31, counterclockwise in this view, around the fan axis. The motor 13 is mounted in the cooling structure 25. The stator 14 is attached in the stator-side mounting area 12 to a stator flange 32, which also serves as a motor mounting flange 16, by means of fastening devices 35, advantageously screws. The cooling structure 25 increases the heat dissipation from the motor 13, in particular its rotor 15, stator 14, etc., during operation of the fan 1.The electronics housing acts in this way in combination with the motor 13, in particular with the rotor 15 and the stator 14 or the electronics housing, as a functional unit with regard to motor cooling.

[0063] The diffuser area 7 widens from the area for the impeller 10 towards the downstream edge of the housing 3. The intermediate ring 4 also widens slightly from the impeller 10 towards its downstream edge. As a result, in the exemplary embodiment, both the inner flow area 18 and the outer flow area 19 are diffuser-shaped, i.e., widening in the flow direction. This is advantageous for high pressure recovery downstream of the impeller 10 and thus for a high static efficiency of the fan 1. The static pressure increase in the flow path between the impeller 10 and the outlet of the fan 1 is particularly advantageous for a possible, beneficial mode of operation of the cooling structure 25 for cooling the motor 13, especially the rotor 15 and stator 14 or electronics housing.

[0064] Within the cooling structure 25, a cooling flow is induced against the main flow direction of the fan 1 by the pressure difference caused by the higher static pressure at the downstream end (relative to the main fan flow) of the cooling structure 25 compared to the lower static pressure at the upstream end. This cooling flow is guided by the downstream cooling channel 27a, following the pressure gradient, to the free end of the upstream cooling channel 27b. The cooling flow essentially flows along the outer wall of the stator 43 or the electronics housing, passes through the cooling passages 35 of the stator flange 26 and the recesses of the rotor flange 34 onto the upstream side of the fan 1, and there again flows along the outer wall of the rotor 44.Thus, the cooling structure 25 separates the cooling flow inside the fan 1 from the main fan flow along its entire axial extent. This allows the pressure difference between the outflow and inflow sides of the fan 1 to be fully utilized, resulting in a larger volume flow of cooling fluid and ultimately improved cooling.

[0065] Fig. 6 shows an axial top view of the fan 1 from the inflow side according to Figs. 1 to 5. In addition to the preceding figures, the flow connection between the outflow-side cooling flow channel 27a and the inflow-side cooling flow channel 27b can be clearly seen in Fig. 6.

[0066] The inflow-side cooling flow channel 27b is formed between the outer wall of the rotor 44 and the surface of the impeller hub 28 opposite the outer wall of the rotor 44. The impeller hub 28 is rotationally fixed to the rotor 15 via a rotor flange 34 by means of fastening devices 37. The fastening devices 37 are uniformly distributed in the direction of rotation on the rotor flange 34, which extends radially into the cooling flow channel 27b. Furthermore, the rotor flange 34 is partially recessed over its surface, so that the rotor flange 34 is ultimately formed from flange sections 38, in particular bolted elements, and the recessed areas act as passages 39 for the cooling flow.

[0067] The downstream cooling channel 27a is formed between the outer wall of the stator 43 and the surface of the hub ring 5 opposite the outer wall of the stator 43. The stator 14, and thus the motor 13, is attached to the hub ring 5 via a stator flange 26 by means of fastening devices 36. The stator flange 26 has cooling passages 35 in certain areas on the flange surface 40, which extends radially into the cooling channel 27a. In addition, cooling fins 41 are formed on the entire circumference of the flange surface 40 such that a portion of the cooling fins 41 project into the cooling passages 35.

[0068] Figures 7a to 7c show a stator 14 for the fan 1 according to Figure 1. Figure 7b shows the stator 14 of a motor 13 in a perspective view from the inlet side, Figure 7c shows the stator 14 in an axial top view from the inlet side, and Figure 7c shows the stator 14 in a perspective view and in section at a plane through the axis of the stator 14. In the exemplary embodiment, the stator 14 has a stator flange 26 extending radially outwards. The stator flange 26 comprises eight fastening provisions 36 for mounting the stator 14 and thus the motor 13 including impeller 10 on the guide vane unit 2. The stator flange 26 is recessed around its circumference on the flange surface 40, where no fastening provision 36 is provided, so that eight cooling passages 35 are created in these areas.Furthermore, a large number of uniformly spaced cooling fins 41 are formed around the entire circumference, some of which project into the cooling passages 35. During fan operation, heat is dissipated via the stator flange 26, with the cooling fins 41 projecting into a cooling passage transferring the heat to the flowing cooling air.

[0069] Figures 8a to 8c show a rotor 15 for the fan 1 according to Figure 1 in a perspective view from the inlet side (Figure 8a), in a side view (Figure 8b), and in a perspective view and section across a plane through the axis of the rotor 15 (Figure 8c). The rotor 15 has a substantially cylindrical basic shape, with the inlet-side end forming a rotor cap 42 and the stator-side end having several flange sections 38 of a rotor flange 34 distributed around its circumference. The impeller 10 is fixedly mounted to the rotor 15 by means of the rotor flange 34 via fastening devices 37. The rotor flange 34 is partially recessed so that the cooling flow induced by the cooling structure 25 can pass through the openings 39 created in the rotor flange. A rotor cap 42, designed to be favorable in terms of flow characteristics, is arranged at the inflow-side end of the rotor 15.

[0070] Regarding further advantageous embodiments of the fan or cooling structure according to the invention, reference is made to the general part of the description and to the attached claims to avoid repetition.

[0071] Finally, it should be expressly pointed out that the exemplary embodiments of the fan or cooling structure according to the invention described above serve only to discuss the claimed teaching, but do not limit it to the exemplary embodiments.

[0072] Reference number list

[0073] Fan, axial fan; supporting guide vane unit; housing of the guide vane unit; intermediate ring of the guide vane unit or diffuser

[0074] Hub ring, outer ring of the cooling structure, inner guide element, guide vanes, outer diffuser wall, diffuser area, strut vanes

[0075] inlet nozzle

[0076] balance bike

[0077] wing of the running wheel

[0078] Stator-side receiving area within the hub ring, hub pot

[0079] Motor

[0080] Stator of the motor

[0081] Motor rotor

[0082] Mounting flange for motor, outer flow area, inner flow area, inflow-side mounting device of the guide unit on the higher-level system

[0083] Downstream mounting device of the guide unit on the higher-level system

[0084] Mounting device for protective grille downstream side not assigned not assigned not assigned Cooling structure a Downstream part of the cooling structure b Inflow side part of the cooling structure Cooling structure flange, stator flange Cooling flow channel a Downstream cooling flow channel b Inflow side cooling flow channel Impeller hub, hub of the impeller Rotor-side receiving area within the impeller hub

[0085] Fastening device for hub cap, direction of rotation of the wheel

[0086] Area for an impeller, winglets, impeller blades, rotor flange

[0087] Cooling passage in the area of ​​the stator flange

[0088] Mounting device for stator flange; Mounting device for rotor flange; Flange section of the rotor flange; Recess in rotor flange, passage; Flange surface of the stator

[0089] cooling fin

[0090] Rotor cap

[0091] Outer wall stator

[0092] Outer wall rotor

Claims

Claims 1. Fan with an impeller and an electric motor, wherein the electric motor comprises a rotor, a stator and optionally an electronics housing and the impeller comprises an impeller hub, wherein a cooling structure is formed or arranged radially outside the outer wall of the rotor and radially outside the outer wall of the stator and / or the electronics housing, which forms a flow path for a fluid, preferably air, through which a flow is induced as a result of a pressure difference generated by the operation of the fan, which dissipates heat from the electric motor, the rotor, the stator and / or the electronics housing.

2. Fan according to claim 1, characterized in that the cooling structure provides at least one cooling flow channel between the outer wall of the rotor and an inner surface of the impeller hub facing the outer wall of the rotor.

3. Fan according to claim 2 characterized in that at least one flow constriction is formed in the cooling flow channel in the flow path between the outer wall of the rotor and the cooling structure, through which the flow is guided at high speed close to the outer wall of the rotor.

4. Fan according to one of claims 1 to 3, characterized in that the electric motor comprises at least one fastening device, in particular a stator flange and / or rotor flange, for arranging the electric motor on a superior structure and / or for arranging the impeller on the rotor, wherein the fastening device is at least partially arranged in the flow path.

5. Fan according to claim 4, characterized in that the fastening device comprises at least one cooling passage, wherein the cooling passage is designed to direct the flow from an inlet side of the fan to an outlet side of the fan (or vice versa).

6. Fan according to claim 3 or 4, characterized in that the fastening device comprises at least one cooling element, in particular a cooling fin, wherein the cooling element is at least partially formed or arranged on and / or in the cooling passage.

7. Fan according to one of claims 1 to 6 characterized in that at least one cooling unit, preferably an axially extending cooling fin, is formed or arranged on the outer wall of the stator and / or the electronic housing.

8. Fan according to one of claims 1 to 7, characterized in that the impeller comprises an impeller hub with an opening for guiding the flow.

9. Fan according to one of claims 1 to 8, characterized in that the cooling structure is not formed by functionally essential components of the motor and does not pass through them.

10. Fan according to one of claims 1 to 9, characterized in that the cooling structure is at least partially formed or arranged on a motor support plate of a radial or diagonal fan or is integrated in a mounting plate.

11. Fan according to one of claims 1 to 10 characterized in that the fan comprises a guide vane with a guide wheel, wherein the guide vane has a support function for the motor.

12. Cooling structure for a fan comprising an impeller including an impeller hub and an electric motor comprising a rotor, a stator and optionally an electronics housing, in particular with the features relating to the cooling structure according to one of claims 1 to 11, wherein the cooling structure is at least partially formed or arranged between the impeller hub and the rotor.

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