Apparatus for cooling an electric fan motor, fan, and method for cooling an electric fan motor

Abstract

The present invention relates to a device for cooling an electric motor of a fan using air, in which the fan generates a pressure difference between the inlet side and the electric motor and outlet side during operation, and this pressure difference is used to guide cool ambient air from the outlet side to the electric motor.

Description

[Technical Field]

[0001] The present invention relates to a device for cooling an electric motor of a fan by means of air, a fan equipped with such a device, and a corresponding method for cooling an electric motor of a fan. [Background technology]

[0002] Fans of thematic type have been known in practice for some time. See, for example, US Pat. No. 6,299,324.

[0003] Fans often operate at high heat loads, for example above 60°C. In particular, for example, in "intake" arrangements where the warm air from the heat exchanger is drawn through a fan, problems arise related to the fan components. In particular, EC fans incorporate electronic devices having temperature-sensitive electronic components. Other components of the fan, such as bearings, insulation, and windings, also have certain upper temperature limits that limit performance and speed. Since the electric motor is in the fan's main transport medium flow, it is not uncommon to use air heated by a heat exchanger to cool the motor. This is true even if the motor or its housing is surrounded by cool ambient air. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2020 / 015792(A1) Summary of the Invention [Problem to be solved by the invention]

[0005] The object of the present invention is to eliminate or at least mitigate the drawbacks occurring in the prior art. For this purpose, special devices for cooling electric motors are provided, which allow for sufficiently good cooling to be achieved with simple means. Such cooling is achieved using the inherent fluid properties and characteristics of the fan. Furthermore, the device according to the present invention is distinguished from competing devices. The same applies to the fan according to the invention and the method according to the invention. [Means for solving the problem]

[0006] The above object is achieved with respect to the device according to the invention by the features of claim 1. According to this feature, during operation, the fan generates a pressure difference between the inlet side and the electric motor and outlet side, and uses this pressure difference to guide cool air from the outlet side ambient area to the hotter electric motor. This cool air cools the electric motor. Therefore, according to the invention, a method for cooling an electric motor of a fan conveying a warm medium flow is implemented. Cooling is achieved by utilizing the cool air present around the outlet side of the fan. Thus, the present invention takes advantage of the flow drive inherent in fans.

[0007] In other words, the electric motor is at least partially cooled by utilizing the cool ambient air surrounding the fan in the area associated with the high pressure outlet side (the pressure side of the fan). The invention makes use of the fact that in the area of ​​the motor a negative pressure always prevails, i.e. the static pressure is low compared to the outflow and pressure side surroundings. The present invention utilizes the pressure difference to precisely guide cool ambient air to the motor for cooling purposes. This air then reaches the outlet side again together with the main conveying flow of the fan.

[0008] One of the key advantages of the device according to the invention is that the cooling in fluid operation is based solely on the flow / pressure field generated by the fan, utilizing only the flow drive inherent to the fan. Therefore, in principle, no special structure or fan redesign is required.

[0009] A cooling pot may be provided surrounding the electric motor or the stator and / or electronics housing of the electric motor, which may be easily integrated into the fan arrangement. The cooling pot has a substantially closed area at least towards the flow side and radially outward, which defines an environment filled with cooling air that is cooler than the main fan flow. This closed area is located in the area close to the axis of the fan.

[0010] A further additional component may be an intake pipe connecting the interior of the cooling pot to the pressure or outlet side periphery of the fan. The intake pipe may be embodied in the form of an intake pipe. At the outlet periphery, higher pressures and lower temperatures prevail than in the main fan flow drawn into the fan inlet nozzle. This is due to the fact that at least part of the free ambient air, which is cooler than the motor area, is present at the point of entry into the intake pipe, e.g., from the ambient atmosphere or from a suitably temperature-controlled free space. By providing an intake pipe or intake pipe, cool air flows through the intake pipe based on a pressure difference into the cooling pot (if one is provided) and onto at least the motor and its components.

[0011] It is further advantageous if the cooling pot has an opening that opens towards the inlet side of the fan, i.e. towards the impeller or its hub, and cooling air can flow out of the cooling pot in the direction of the impeller hub through this opening. The cooling flow leaving the cooling pot may be guided to enter the main cooling system of the electric motor, for example the stator flange of the electric motor may be formed with cooling ribs for dissipating heat. Other suitable means for heat exchange may alternatively or additionally be provided.

[0012] Also, the cooling pot is located near the shaft or hub in a region downstream of the impeller, in which the main fan flow has a significantly higher circumferential velocity. This results in a pressure field in which the static pressure radially inward, i.e., near the axis, is significantly lower than the static pressure radially outward. This is especially true when compared to the outer area of ​​the housing. Thus, the cooling air flows through the intake pipe towards or into the cooling pot, then flows through an opening in the cooling pot towards the outside or inlet side of the fan and into the cooling system in which the motor is incorporated. The cooling air then mixes with the main fan flow.

[0013] It is an advantageous design if the cooling pot and / or suction pipe are integrally incorporated into the motor and impeller support structure. This integration may advantageously be implemented in the support and guide unit of the fan.

[0014] Additionally, a flow guide is provided within the cooling pot, which guides the cooling air at a relatively high velocity and / or high turbulence near the wall of the electronics housing or stator to be cooled. This improves the cooling effect.

[0015] The fan according to the invention achieves the object stated at the beginning by the features of the other independent claim 13, the fan comprising a device according to the invention in accordance with the preceding description.

[0016] What is considered here is that the fan draws in air that has previously flowed through the heat exchanger on the inlet side. As a result, the temperature of the air increases.

[0017] In an advantageous embodiment, there is no cooling pot surrounding the motor, and cooling air is guided to the interior region of the motor (or its electronics pot and / or stator) through one or more intake pipes. For this purpose, the intake pipe is connected directly or indirectly to an interface on the motor side which is provided for the inflow of cooling air.

[0018] When cooling air enters the interior of the motor through one or more intake pipes, an internal cooling air passage or one or more internal cooling air regions are formed through which the cooling air can flow and absorb the waste heat of the motor. After flowing through the interior of the motor, the heated cooling air exits the interior of the motor through one or more outlet openings for the cooling air.

[0019] The internal cooling air passage or cooling air area through which the cooling air flow inhaled through one or more intake pipes flows is encapsulated and formed separately from the electronic equipment area or winding area or other electrical or electronic components (if formed), thereby preventing wet or dirty cooling air from coming into direct contact with the electrical or electronic components.

[0020] The interface on the motor, which serves as the cooling air inlet, is designed to allow the optional connection of an intake pipe. This interface is configured to be easily connectable without the need for tools, for example, by latching or snap hooks.

[0021] In a further advantageous embodiment, a functional element, for example a separate fan or fan wheel, intensifies the flow of cooling air through the intake pipe and the cooling pot or internal cooling air channels or areas.

[0022] To increase the cooling air flow rate and achieve better cooling effect, a separate small fan, such as a housing fan, may advantageously push the cooling air from the outer pressure side periphery at the inlet of the intake pipe through the inlet of the intake pipe.

[0023] Due to the high exit velocity of the exiting air, the hot air in the main flow of the fan rushes out of the fan downstream of the fan, and this hot air does not reach the inlet area of ​​the suction pipe and therefore is not sucked therefrom.

[0024] The method according to the invention achieves the object stated at the beginning by the features of the further independent claim 18, the method using the device according to the invention and / or the fan according to the invention.

[0025] There are various possibilities to design and improve the invention in an advantageous manner. To this end, reference is made on the one hand to the appended claims and on the other hand to the following description of an embodiment of the cooling device according to the invention based on the drawing. Embodiments and improvements of the present invention will be outlined in conjunction with the description of the embodiments of the present invention based on the drawings. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a perspective view of a fan, seen from the outflow side, comprising a support guide unit with a housing and guide vanes, and a cooling device according to the invention; [Figure 2] 2 is a perspective view of a fan equipped with the cooling device of FIG. 1, viewed from the inlet side. [Figure 3] 3 is a side view of a fan equipped with the cooling device of FIGS. 1 and 2, in section along a plane passing through its axis; FIG. [Figure 3a] 4 is a detailed view of the cooling pot area of ​​the cooling device of FIG. 3; [Figure 4] 4 is a plan axial top view of a fan equipped with the cooling device of FIGS. 1 to 3, as viewed from the outlet side. FIG. [Figure 4a]1 to 4, viewed from the outlet side, in which, unlike FIG. 4, the outlet cover of the cooling pot is not shown, so that the elements inside the cooling pot are visible. [Figure 5] 1 is a perspective view of an integrated part of the cooling device, including an element of the cover of the cooling pot facing the pressure side and the intake pipe. [Figure 5a] 1 is a perspective view of an integrated part of the cooling device, including the elements of the cover of the cooling pot facing the pressure side and the connection of the intake pipe. [Figure 6] 1 shows a perspective view of the fans from the outflow side, in which the ventilation device has two fans that draw air through a heat exchanger, each fan having a support guide unit and a cooling device. [Figure 7] 1 shows a perspective view from the outlet side of a fan comprising a support guide unit with a housing and guide vanes and a cooling device according to a further embodiment of the invention with an axially oriented intake pipe; [Figure 8] 8 is a side view of a fan equipped with the cooling device of FIG. 7, in cross section along a plane passing through the axis. [Figure 9] 1 shows a side view, in section along a plane through the axis, of a fan comprising a support guide unit with a housing and guide vanes and a cooling device according to a further embodiment of the invention having an axially oriented intake pipe with an equivalent flow cross-section that varies in the axial direction. [Figure 10] Figure 1 illustrates the relative improvement achieved in experiments on the experimental rig, i.e., the reduction in the temperature of thermally critical electronic components as a function of the temperature difference between the fan main flow and the pressure side ambient, for two different diameters of the inlet tube. DETAILED DESCRIPTION OF THE INVENTION

[0027] FIG. 1 is a perspective view of an axial fan 57 equipped with a support guide unit 1 having a cooling device 40 according to the present invention, viewed from the outlet side. The support guide unit 1 specifically includes a cooling pot 8, an intake pipe 12, and a cooling pot cover 43. The support guide unit 1 is composed of a housing 2, an intermediate ring 5, a hub ring 4, inner guide vanes 11 extending between the hub ring 4 and the intermediate ring 5, and support vanes 3 extending between the intermediate ring 5 and the housing 2 or its radial expansion region 10. The support and guide unit 1 is manufactured in one piece by a casting process, preferably by plastic injection molding. The hub ring 4 also forms an outer ring, which is the outer wall of the cooling pot 8 .

[0028] The housing 2 defines the outer boundary of the fan throughflow (also called the main fan flow) which extends inside the housing 2 . When viewed in the direction in which the main flow of the fan passes, the housing 2 is made up of a plurality of regions. The multiple regions are first the inlet nozzle 9, then the preferably cylindrical region 29 in which the impeller 19 with the blades 22 is arranged, and finally the radially expanding region 10 in which the support blades 3 are fixed.

[0029] Also, downstream of the impeller 19 in the housing 2, an inner guide device is arranged, which extends between the hub ring 4 and the intermediate ring 5 and is made up of inner guide vanes 11 that perform a fluid function. The fluid action of the inner guide vanes 11 in cooperation with the intermediate ring 5 within the hub ring 4 improves static efficiency and aerodynamic performance, particularly static pressure, at a specific conveying volume flow rate, and the volume flow rate of the main fan flow drawn into the fan 57 through the inlet nozzle 9 of the fan 57 becomes particularly high.

[0030] The hub ring 4 complements the radial outer wall of the cooling pot 8 of the cooling device 40 . The cooling pot cover 43 substantially closes the cooling pot 8 from the fan mainstream, so that the cooling pot 8 has an opening or flow path connection to the fan mainstream only on its front surface (not shown) facing the impeller 19 or inlet nozzle 9 (see also Figures 3 and 3a). A cooling air pipe 12 or intake pipe 12 is connected to the cooling pot 8 . The intake pipe 12 extends substantially transversely to the main fan flow, and blocks the internal throughflow containing cooling air from the main fan flow. For the throughflow of cooling air, this intake pipe 12 connects the interior of the cooling pot 8 with the area assigned to the pressure side of the fan 57 (see also FIG. 6 ) radially outside the fan 57 or the support and guide unit 1 or its housing 2, and for this purpose the intake pipe 12 crosses the wall of the housing 2.

[0031] At the outlet end of the housing 2, it is also conceivable to pass the suction pipe 12 through on the outlet side. Due to the operation of the fan 57, the total pressure or static pressure of the main fan flow conveyed by the fan 57 is higher on the pressure side assigned to the outlet end of the diameter expansion region 10 than on the suction side assigned to the inlet nozzle 9. Fan 57 creates this pressure gradient, causing air to flow radially outward into cooling device 40 or its inlet tube 12 , through inlet tube 12 and into cooling pot 8 . The electric motor to be cooled is placed in the cooling pot 8. This air then flows from the cooling pot 8 through an opening into the impeller 19 of the fan 57, where it mixes with the main fan flow. In many typical systems (see also FIG. 6 for an example), the temperature of the main fan air drawn in from the inlet nozzle 9 is significantly higher than the temperature of the ambient air outside the housing 2 of the fan 57, on the outlet or pressure side of the fan 57. This outlet or pressure side often corresponds to the free air ambient or a large, moderately temperature controlled space into which the fan 57 blows its main fan flow. This means that the temperature of the cooling air drawn in through the intake pipe 12 and flowing into the cooling pot 8 is significantly lower than that of the main airflow from the fan. Therefore, the electric motor located within the cooling pot 8 is at least partially located in a lower temperature environment than, for example, the impeller 19 of the fan 57, whose blades 22 are exposed to the high temperatures of the main fan flow. Thus, the cooling of the electric motor can be significantly enhanced or improved.

[0032] An outer support vane 3 is provided to hold the motor 34 shown in FIG. 3, which includes the impeller 19 and the inner guide unit, in the outer housing 2 . The outer support vanes 3 only play a secondary role in terms of hydraulic function and are primarily used to secure the inner guide unit, and thus the motor 34 and impeller 19, to the outer housing 2. The outer support blades 3 are designed to be advantageous in terms of noise, so that when the fan 57 is in operation, the presence of the outer support blades 3 generates little or no noise. Overall, two different through-flow regions are formed inside the housing 2 in the axial region of the diameter expansion region 10 when viewed in the span direction (from the hub ring 4 towards the diameter expansion region 10). One is an outer through-flow region 6 between the intermediate ring 5 and the wall of the radially expanded region 10 of the housing 2 , and the other is an inner through-flow region 7 between the hub ring 4 and the intermediate ring 5 .

[0033] The inner through-flow region 7 is provided with fluidically active supporting inner guide elements 11, which, for example, reduce flow turbulence, increase static pressure, avoid or reduce backflow in the hub region, and, due to their radially inner location, also generate little noise.

[0034] The outer through-flow region 6 is likewise provided with support vanes 3, six in number, preferably four to eight, distributed around the circumference and designed to be noise-optimized. The support and guide unit 1 is integrally provided with a number of flanges on the inlet and outlet sides in the edge region of the housing 2, which flanges include different fastening means.

[0035] It should be noted here that the cooling device 40 according to the present invention can also be used for fans having a guide wheel without an intermediate ring 5, in which case the guide vanes (which are preferably also the outer wall of the cooling pot 8) extend continuously from the hub ring 4 to the housing 2. In particular in such an embodiment, the suction pipe 12 preferably extends alongside the guide vanes, and may be wholly or partly integrated with the guide vanes, and preferably uses the guide vanes as a wall at least in part or is fixed to the guide vanes. Multiple intake pipes 12 may be used, for example with multiple guide vanes.

[0036] The cooling device 40 according to the present invention may also be used for a fan without guide vanes, in which case a hanging support member must be provided for attaching the motor 34 to the housing 2, and this hanging support member may also be used to fix the suction pipe 12. More advantageously, the intake pipe 12 may be integrated into the suspension support. All that matters is that the cold air be guided from the periphery of the pressure side to the cooling pot 8 without mixing with the main fan flow, or at most only very slightly. In other embodiments, the intake pipe 12 may be embodied in any convenient manner, for example as a hose, pipe, flexible pipe, etc., in the form of a standard product available on the market. It is important that the inside diameter of the intake pipe 12 is large enough to convey sufficient cooling air to the cooling pot 8 .

[0037] For example, the inner diameter (or equivalent hydraulic diameter in the case of a non-circular cross section) may be greater than 5% of the diameter of the impeller 19 of the fan 57, and preferably greater than 10%. When multiple suction pipes 12 are used, the equivalent hydraulic diameter of the total cross-sectional area of ​​all the suction pipes 12 is the basis for determining the dimensions. On the other hand, since the intake pipe 12 extends laterally to the main flow of the fan, it is necessary to ensure that it does not become an excessively large obstacle. Therefore, the use of a one-piece or combined structure including guide vanes or suspended support members, or an elongated non-circular cross-sectional shape, or a plurality of elongated intake pipes 12, is particularly advantageous.

[0038] The inlet flange is provided with a fixing means 20 for fixing the support guide unit 1 and thus the fan 57 to a higher-level device or system, and the outlet flange is provided with a fixing means 21 for fixing the support guide unit 1 to a higher-level device or system such as a cooling device (chiller) or heat pump.

[0039] Furthermore, the outlet flange is provided with fastening means 25 for a contact protection grid, and may be provided similarly on the inlet flange. The contact protection grid may be screwed into a counterbore in the area 25 so that it does not protrude axially above the support and guide unit 1 . This makes the fan 57 more portable and stackable. For this purpose, the cooling device 40 according to the invention, which comprises in particular the intake pipe 12 and the cooling pot 8 with the cooling pot cover 43, is arranged in its entirety axially between the inlet flange and the outlet flange of the support and guide unit 1 of the fan 57.

[0040] FIG. 2 is a perspective view of the fan 57 provided with the cooling device 40 of FIG. 1, seen from the inlet side. In addition to the configuration shown in FIG. 1, the impeller 19 having the blades 22 integrally secured to the hub 31 can be seen more clearly. A hub hood 37 is fixed to the hub 31 of the impeller 19 and engaged with it using a catch hook. Furthermore, the hub hood 37, together with the hub 31, ensures a flow-promoting shape in the hub region of the impeller 19, which is advantageous for high efficiency and low noise. The rotor 35 of the motor 34, here an external rotor electric motor, can be seen inside a hub hood 37 which has a large opening in its radially inner area. By providing an inner opening in the hub hood 37, the rotor 35 of the motor 34 can be cooled effectively by utilizing at least the mainstream air of the fan. It is also conceivable to design the impeller hub 31 in such a way that its inlet side is closed, in order to use the cold air from the cooling device 40 flowing in from the suction pipe 12 to form a flow around the rotor 35 in whole or in part.

[0041] During operation of the fan 57, the impeller 19 is driven by the rotor 35 of the motor 34 to which the impeller 19 is fixed, and rotates in a direction of rotation 32, for example clockwise here. As a result, the conveying medium (often air) is conveyed by the fan 57 from the inlet side, which can be seen in the foreground of the figure, in the through-flow direction, through the axial regions of the inlet nozzle 9, impeller region 29, and diameter expansion region 10, to the outlet side, which is axially opposite the inlet side, as the fan's main flow. In particular, energy is transferred to the transport medium flow conveyed in this way, which can be measured in the form of a pressure rise, in particular a total pressure rise and / or a static pressure rise. Here, this conveying medium flow splits downstream of the impeller 19 into two main components. One component flows through the outer perforated region 6 and the other component flows through the inner perforated region 7 .

[0042] The impeller 19 with its blades 22 adds a large circumferential component to the flow velocity of the main fan flow, which occurs immediately after the main fan flow passes the impeller 19 . This circumferential velocity necessarily creates a static negative pressure in the area close to the axis compared to areas further away from the axis, and in particular compared to areas of the housing 2. The static pressure in the housing 2 approximately matches the ambient pressure at the outlet of the main fan flow from the radial expansion region 10, or at the outlet end of the housing 2, at the pressure side periphery which communicates with the outer end of the intake pipe 12 (Figure 1). This means that the pressure at the outer end of the intake pipe 12 is higher than the pressure in the cooling pot 8, which is located near the axis and communicates with the main fan flow, and air necessarily flows from the outside to the inside through the intake pipe 12 into the cooling pot 8. In many applications, this air will be at a lower temperature than the main fan airflow, which is particularly advantageous when used to cool, for example, the electric motor 34 in the cooling pot 8 . After passing through the cooling pot 8, the cooling air leaves the cooling pot 8 into the area between the cooling pot 8 and the hub 31 of the impeller 19, from where it also flows firstly into the main cooling system of the electric motor 34, which has stator cooling ribs 50 integrated into the stator 36, where it significantly contributes to improving the cooling of the electric motor 34.

[0043] FIG. 3 shows a fan 57 comprising the cooling device 40 of FIGS. 1 and 2 in a side view in section through a plane passing through its axis, where the motor 34 and impeller 19 are not shown in section. FIG. 3 a shows a detailed view of the area of ​​the cooling pot 8 which is part of the cooling device 40 and is bounded radially outward by the hub ring 4 . In addition to the relevant diagrams, the contour of the aerodynamically-friendly hub hood 37 attached to the hub region of the impeller 19, which is tangentially connected to the hub 31 of the impeller 19 and has a rounded shape, can also be seen very clearly here. The impeller 19 having the hub 31 and the blades 22 is fixed to the rotor 35 of the motor 34 (see FIG. 2 ) and has a small radial dimension, so that there is a flow gap between the blades 22 of the impeller 19 having the winglets 38 and the impeller region 29 of the housing 2. Here, this impeller region 29 is the axial region in which the impeller 19 is approximately located.

[0044] In the motor 34 consisting of a stator 36 and a rotor 35 , the stator 36 is disposed in the cooling pot 8 . The stator 36 has the electronics pot 13 integrated therein and is fixed to the front flange 54 of the cooling pot 8 . This front flange 54 also functions as a motor fixing flange 59 . Thus, the motor 34, in cooperation with the forward flange 54, defines a cooling pot 8 relative to the rotor side of the motor 34, i.e., relative to the inlet side of the main fan flow on the right side as shown. However, the cooling pot 8 is not completely sealed off from the rotor side, and cooling air flows out toward the rotor side through a cooling path 42 . The cooling pot 8 is substantially sealed by a cooling pot cover 43 on the outlet side of the main fan flow on the left side in the drawing. The intake pipe 12, which has an inlet 23 outside the housing 2 in the pressure-side connection space of the fan 57, may likewise be a connection to a pipe of another cooling flow and opens into the interior of the cooling pot 8.

[0045] When the fan 57 is operating, a pressure field is generated, causing air to flow from the pressure-side connection space across the fan mainstream into the cooling pot 8, then flow through the cooling path 42 to the rotor side, and finally merge and mix with the fan mainstream before being transported to the outlet side of the fan 57. This cooling airflow may particularly advantageously contribute to the cooling of the electric motor 34 (here preferably embodied as an external rotor motor incorporating control electronics) in various ways along its path. First, the temperature inside the cooling pot 8 drops, so that the outer wall of the stator 36 inside the cooling pot 8 and the outer wall of the electronic device housing 13 fixed on or integrated with the stator 36 are cooled. This means that heat is effectively dissipated into the relatively cool cooling air (compared to the mainstream fan air).

[0046] It is also particularly advantageous if the cooling air is guided through a cooling flow path 41 defined by the cooling flow guide 14, which passes at a relatively high flow velocity close to the outer wall of the electronic device housing 13 to be cooled. It is particularly advantageous if it is guided to areas where particularly good cooling is required, such as near power electronic components (such as output stages (IGBTs), input stages, etc.) that strongly dissipate heat inside the electronics pot 13, or near components that are particularly temperature-sensitive. This makes the cooling efficiency in these areas particularly high. In a further path of the cooling flow, the cooling air leaves the cooling pot 8 towards the rotor side through one or more cooling channels 42 .

[0047] In the embodiment, a rotor-side receiving area 46 is also provided, which represents an area that is also radially outwardly defined by the hub ring 4, and in which the flange 49 of the stator 36 is located and fixed to the motor support flange 59 or front flange 54 of the cooling pot 8. Stator cooling ribs 50 are advantageously formed on stator flange 49, which is a key heat dissipating element of the motor's 34 main cooling system. The cooling fan wheel 51 attached to the rotor 35 draws in cooling air that has already passed through the cooling ribs 50 of the stator 36 at an inlet area located radially inward, and then releases this cooling air, which has absorbed waste heat at the stator cooling ribs 50, radially outward. In this radially outer region, this cooling air mixes with the main fan flow and is further conveyed towards the outlet side of the fan 57 . In any case, in the cooling device 40 according to the invention, the cooling air flowing out of the cooling pot 8 passes through at least one cooling path 42 before being introduced into the main cooling system of the motor 34 by the action of the main cooling system of the motor 34 and is guided through the stator cooling ribs 50, where it can absorb heat particularly effectively due to its relatively low temperature. The cooling device 40 then utilizes the existing main cooling system of the motor 34 and introduces particularly cool air thereto, thereby significantly increasing the effectiveness of the main cooling system without consuming additional power or generating additional noise.

[0048] Reinforcing ribs 58 are also provided on the inside of the cooling pot 8 to strengthen and stabilize the connection between the motor 34 and the support and guide unit 1 with which the cooling pot 8 is integrated. This reinforcing rib 58 strengthens the connection between the hub ring 4 of the support and guide unit 1 and the fixing flange 59 of the motor 34, which also serves as the flange of the cooling pot 8 or its rotor-side boundary.

[0049] It is conceivable to provide a replaceable insert in the hub ring 4, i.e. in the inner region of the cooling pot 8, in the molding die for producing the support and guide unit 1 with the integrated cooling pot 8 of the cooling device 40. This allows for different interfaces to different motors and / or different embodiments of the cooling device 40 which are manufactured integrally with the support and guide unit 1 here. In addition to the perforated circle for fixing the motor 34, for example, the axial threaded surfaces of the motor 34 may also be provided at various positions, and the axial position of the cooling device front flange 54 / motor support flange 59 within the cooling pot 8 may also be various. The presence or absence or shape of the cooling flow guide portion 14 may also vary and may be adjusted to suit the motor to be provided.

[0050] The motor 34 is here an external rotor motor, more preferably implemented as an EC motor, advantageously with an integrated motor electronics housing 13, and the stator 36 of the motor 34 can also be seen. The stator 36 has an electronics pot / electronics housing 13 integrated therein. The electronics pot / electronics housing 13 may be secured to the stator 36 as a separate component. In its operating mode, the cooling device 40 facilitates the dissipation of waste heat at the stator 36 of the motor 34 and, in particular, from the electronics pot 13 thereof. This heat dissipation is promoted by conveying cooling air, which is cooler than the main fan flow, to the motor 34 area in the cooling pot 8 through the intake pipe 12 for cooling purposes, but is also promoted by a special fluid design inside the cooling pot 8. Thus, the electromagnetically operating components and electronic components are better cooled, allowing the motor 34 to provide higher torque and therefore higher power at the same ambient or transport medium temperature.

[0051] The cooling pot 8 is designed so that the entire cooling pot, including the cooling flow guide 14, can be demolded from a casting tool, in particular a plastic injection mold, in one piece without undercuts, without the cooling pot cover 43 being removed. Specifically, two mold parts are used and the mold is axially demolded from one mold part to the other. One of these molding die parts is released to the right as viewed from the fan inlet side, and the other is released to the left as viewed from the fan outlet side. The narrowest point between the cooling flow guide 14 and the stator 36 or electronics pot 13 is therefore located near the edge of the cooling flow guide 14 opposite the stator flange 49 . This is particularly advantageous for the cost-effective manufacture of corresponding molds and for the cost-effective manufacture of the part (cooling device 40) in mass production.

[0052] FIG. 4 shows a fan 57 equipped with the cooling device 40 of FIGS. 1 to 3 in axial top view from the outflow side, in which the cooling pot 8 is integrated in the support and guide unit 1. 1 to 3, the path of the intake pipe 12 transverse to the main fan flow, crossing the inner through-flow region 7 and the outer through-flow region 6, can be clearly seen. The inlet pipe 12 runs generally alongside the inner guide vanes 11 and support vanes 3 to minimize the effect of obstructing the main fan flow.

[0053] The suction pipe 12 may be fixed to the inner guide vane 11 or the support vane 3, or may be manufactured as a hollow guide vane that is completely or partially integrated with the inner guide vane 11 or the support vane 3, for example. Furthermore, the cable connection 44 of the cooling pot 8 can be seen. This is because the power cable and possibly electrical control lines must be guided from the outside of the fan 57 and housing 2 into the cooling pot 8 and to the electric motor 34 and its stator 36 . It is also conceivable to provide these electrical lines inside the suction pipe 12 . This saves on the cable connection 44 and also saves on a separate path on the outer housing 2 for the cable. This advantageous design ensures that the electrical lines are not affected by the high temperatures of the main fan flow.

[0054] Figure 4a shows a planar axial top view of the fan 57 equipped with the cooling device 40 of Figures 1 to 4, seen from the outlet side; unlike Figure 4, the outlet cover 43 of the cooling pot 8 is not shown, so that the elements inside the cooling pot 8 and the electronics housing 13 of the stator 36 or motor 34 can be seen. The cooling flow guide 14 is clearly visible and guides the relatively high flow rate cooling air close to the outer wall of the electronic device housing 13 to be cooled, where it can effectively absorb waste heat. The cooling air is then discharged from the cooling pot 8 in the direction of the rotor 35 or impeller 19 through the cooling air passage 42 behind it. The motor 34 is fixed together with the stator 36 by means of fixing means 18, preferably by screws, to a motor support flange 59, which also constitutes the rotor-side boundary of the cooling pot 8.

[0055] An embodiment in which the cooling flow guide 14 is not provided is also conceivable. However, it is particularly advantageous if the cooling flow guide 14, and thus the cooling channel 41 (Figure 3a), is arranged at a very short distance from the outer wall of the stator 36 or the electronics pot 13 in at least some areas, relative to the centerline as viewed in cross section. However, it is particularly important that the cooling passage 42 is formed in at least the axial region of the cooling pot forward flange 54 in order to cooperate with the electric motor 34 when the fan 57 is operating to achieve the above-mentioned flow through the cooling pot 8.

[0056] FIG. 5 shows a perspective view of an integrated part of the cooling device 40 including the elements of the cooling pot cover 43 and the intake pipe 12 of the cooling pot 8 facing the outlet side of the fan 57 (of FIGS. 1 to 4). The cooling pot cover 43 essentially consists here of a relatively flat axial end region 45 and of a lateral region 47 in which the intake pipe 12 is attached. The side regions 47 are preferably formed complementary to corresponding recesses on the hub ring 4 of the cooling pot 8 . In the assembled state, the cooling pot 8 thus forms an area that is closed off (with the exception of the intake pipe 12) towards the outlet side of the fan 57. The illustrated component can be produced by plastic injection molding, with the inner region of the intake pipe 12 being molded using water or air displacement in the injection molding process.

[0057] Figure 5a shows a perspective view of an integrated part of the cooling device 40 including the elements of the cooling pot cover 43 of the cooling pot 8 facing the outlet side of the fan 57 (from Figures 1 to 4) and the connection 63 of the intake pipe 12. The illustrated cooling device 40 does not have an integrated suction pipe 12, but has an integrated connection portion 63 (for example, a suction hose) for the suction pipe 12. Any type of commercially available flexible hose may be connected, in particular cable conduits (used for example when laying cables under floors or underground). It is important to select a diameter for the intake pipe 12 and thus for the connection 63 that is sufficient for the through flow. Therefore, it is preferable that the minimum effective cross-sectional area of ​​the cooling flow in the region of the intake pipe 12 (total of all intake pipes 12 if there are several intake pipes 12) is not substantially smaller than the minimum effective cross-sectional area of ​​the further flow path up to the outlet of the cooling pot 8 (see Figures 3 and 3a).

[0058] FIG. 6 shows a perspective view of two fans 57 from the outflow side, in which a ventilation device 64 has two fans 57 that draw air through a heat exchanger 65, and each fan 57 has a support guide unit 1 and a cooling device 40.

[0059] In the embodiment shown, a ventilation device 64 is shown having a V-shaped heat exchanger 65 and two fans 57 each having a cooling device 40 .

[0060] During operation, the fan 57 draws ambient air through the heat exchanger 65 into the interior of the ventilation device 64 formed by the device wall 66 and the nozzle plate 56 . This causes the air to be warmed and at the same time heat is taken from the heat exchanger 65 or the cooling air circulating within the heat exchanger 65 . This heat reaches the heat exchanger 65 via a cooling circuit having a supply pipe 68 and a connection 67, and then passes through the interior of the ventilation device 64 to the ambient air sucked in by the fan 57. Therefore, the main flow passing through the fan 57 that draws warm or hot air from inside the ventilation device 64 is exposed to a high conveying medium temperature.

[0061] However, due to the function of the cooling device 40, the electric motor 34 of the fan 57 is at least partially cooled by the cool ambient air. This cool ambient air is drawn into the intake pipe 12 through the inlet 23 without being heated by the heat exchanger 65, and then reaches the area near the motor 34 where it is used to cool the motor 34. The intake pipe 12 can be considered a hydraulic bypass for flow through the heat exchanger 65, as it directs cool ambient air directly to the area adjacent the motor 34 without passing through the heat exchanger for enhanced cooling.

[0062] As explained with reference to the embodiment shown in FIGS. 1 to 4, the cooling device 40 significantly improves the cooling of the installed electric motor 34. In a surprisingly simple manner, it is possible to enable the motor 34 or the fan 57 to operate at very high conveying medium temperatures, while avoiding the shortened lifespan of the motor 34 due to overheating. This makes it possible to particularly increase the cooling capacity or cooling capacity density of such a ventilation device 64 (eg, cooling device 40).

[0063] The air in the main flow of the fan discharged from the outlet of the fan 57 is at a relatively high temperature, and therefore it is advantageous if it is discharged by the fan 57 at a relatively high speed, for example, in a jet-like manner, that is, if it flows out from the fan 57. This prevents already heated air from flowing into the inlet 23 of the intake pipe 12 and thus into the cooling device 40, thereby preventing the effectiveness of the cooling device 40 from being significantly impaired. In the fan 57, for example, the support and guide unit 1 having inner guide vanes 11 as in the embodiment of Figures 1 to 4 may contribute to such an outflow behavior, i.e. to avoiding thermal short circuits. Furthermore, with regard to the effectiveness of the heat exchanger 65, it is also important to avoid thermal short circuits. It is also conceivable to connect a further pipe to the inlet 23 of the intake pipe 12, to serve as an air intake connection where sufficient cool air is assured to be present.

[0064] Figure 7 shows a fan 57 in a perspective view from the outflow side, comprising a support guide unit 1 with a housing 2 and inner guide vanes 11 or support vanes 3, and a further embodiment of a cooling device 40 according to the invention with an axially oriented suction pipe 12. The structure of the fan 57 having the impeller 19, the motor 34, and the support and guide unit 1 including the cooling pot 8, as well as the configuration in its internal area, are similar to the fan 57 shown in Figures 1 to 4, and for an explanation of the corresponding features, please refer to the corresponding explanations in each figure. However, the cooling system 40 has a modified design. Therefore, the cooling pot 8 is not provided with a cover (see also FIG. 8), and the cooling pot 8 is open toward the outflow peripheral portion on the pressure side relative to the fan mainstream. The suction pipe 12 is axially adjacent to the cooling pot 8 across the opening of the cooling pot 8 and projects axially beyond the support and guide unit 1 or the housing 2 of the fan 57 into the pressure side periphery of the fan 57 . Here, the inner diameter of the suction pipe 12 is approximately equal to the inner diameter of the cooling pot 8 .

[0065] It is important that the intake pipe 12 is tightly connected to the cooling pot 8 and that there are no significant leaks, which also requires sealing the area where the electrical cable guides or electrical connections 44 for the motor cables are pulled radially outwards from the cooling pot 8. A corresponding design for sealing may be incorporated, for example, in the intake pipe 12 . In this embodiment, the intake pipe 12 does not extend transversely to the main fan flow, but extends substantially parallel to the main axial transport direction of the main fan flow through the fan 57 .

[0066] The cold air from the pressure side periphery enters the suction pipe 12 through its open end and may flow in a known manner into the cooling pot 8 where it may provide a better cooling effect. In the area on the pressure side of the axial flow fan 57, close to the imaginary extension of the fan axis, at least when observing the flow conditions slightly downstream of the pressure side of the fan 57, backflow may occur periodically. This is related to the fact that the main fan flow has an outward radial component after leaving the housing 2 and in a sense splits to form a vortex system. This induces a backflow of fluid in the interior region downstream of the fan 57, near the shaft. Such a reverse flow region causes cooler air from the pressure side periphery to flow closer to the fan 57 in the region near the shaft. This cold air is drawn into the suction pipe 12 due to the design of the suction pipe 12 as shown and, as a result of the pressure difference created by the fan 57, is guided into the cooling pot 8 and into the cooling channel 42 (see Figure 8) in front of the cooling pot 8.

[0067] FIG. 8 shows a fan 57 comprising the cooling device 40 of FIG. 7 in a side view in section along a plane passing through its axis. As a complement to FIG. 7, the connection area 30 of the intake pipe 12 at the cooling pot 8 can be seen better. The connection can be implemented in various ways, for example by screwing the cooling pot 8 and / or the intake pipe 12 with corresponding threads, respectively. Connections using clamps, hooks, etc. are also contemplated, as are connections using methods similar to adhesive bonding or bayonet connections.

[0068] It should also be explicitly mentioned that the intake pipe 12 can be manufactured integrally with the cooling pot 8 and in one piece. It is important that the intake pipe 12 does not extend transversely to the fan mainstream, but is formed so that it protrudes from the housing 2 beyond the outlet of the fan mainstream in the axial direction, in a region near an axis that is approximately parallel to the main transport direction. Specifically, it protrudes at least 5%, preferably at least 20%, of the diameter of the impeller 19 of the fan 57 . In the case of a similar embodiment, particularly a long intake pipe 12, it may be advantageous to provide means for fixing the intake pipe 12 in a horizontal configuration (here meaning that the conveying direction is horizontal) directly to the outer housing 2 near the outlet, for example by means of at least one wire, cord, cable, etc.

[0069] In such a fan 57, it is often necessary to attach a contact protection portion (protective grid) that prevents contact from the pressure side of the fan 57. A contact protection grid suitable for this purpose is often attached to the outlet side of the fan 57 , to the support and guide unit 1 or to the housing 2 . The provision of a contact protection grid having an opening on the inside, through which the intake pipe 12 protrudes in the axial direction, is advantageous because there is no risk of contact with the rotating elements in the radial direction inside the intake pipe 12, thus preventing free access to the rotating elements. It is particularly advantageous if the intake pipe 12 of similar design is integrated in one piece into the contact protection grid, for example as a welded structure or as a one-piece injection-molded component.

[0070] It is important to make a substantially leak-tight connection between the intake pipe 12 and the cooling pot 8 at the connection point 30 . In Figure 8 it can be seen that the area of ​​the cable connection 44 presents a particular challenge in this respect. In this area, it may be necessary to install special parts for sealing purposes if these cannot be advantageously integrated into the intake pipe 12 or the cooling pot 8 . Generally, it is conceivable to provide a sealing element, such as a rubber seal, at the joint 30 between the intake pipe 12 and the cooling pot 8 . In the embodiment shown in Figures 7 and 8 or 9, the air in the fan mainstream is at least partially drawn in from the open end of the intake pipe 12, resulting in mixing of the cool air in the pressure side surrounding area with the fan mainstream.

[0071] The greater the proportion of hot air in the main fan flow, the worse the cooling effect of the cooling system according to the present invention. In order to suppress this effect and to suck in as much cold air components as possible from the pressure side periphery, the suction pipe 12 may be configured to protrude axially from the outlet of the housing 2 into the pressure side region as far as possible, for example by at least 20% of the impeller diameter.

[0072] Figure 9 shows a fan 57 in a side view in cross section along a plane passing through its axis, comprising a support guide unit 1 having a housing 2 and inner guide vanes 11 or support vanes 3, and a cooling device 40 according to a further embodiment of the invention. This embodiment of the cooling system 40 also comprises an axially oriented intake pipe 12, similar to the embodiment according to FIGS. This intake pipe 12 is axially connected directly at a connection point 30 to the cooling pot 8 which is open axially towards the pressure side and projects axially beyond the housing 2 into the pressure side periphery.

[0073] The suction pipe 12 has a varying equivalent flow cross section over its entire length, with the diameter D1 at the inlet 40 to the suction pipe 12 being smaller than the diameter D2 at the connection point 30 towards the cooling pot 8 at its free end protruding into the pressure side periphery. The flow cross section of the intake pipe 12 here corresponds approximately to a circular cross section of varying diameters, but may also have other cross-sectional shapes that deviate from circular, for example towards the open end 40, in which case the equivalent hydraulic diameter is used to determine the dimensions of the diameters D1, D2.

[0074] In other embodiments, the diameter D1 at the entrance 40 to the intake pipe 12 may be larger than the diameter D2 at the connection 30 to the cooling pot 8. In order to maximize the cooling effect of the cooling system according to the present invention, it is advantageous to design the cross-sectional shape and the ratio of the diameter D2 to the diameter D1 so that the component of the warm fan mainstream air drawn into the suction pipe 12 is as small as possible, and the component of the cold pressure side peripheral air drawn into the suction pipe 12 is as large as possible. These air components may vary depending on the operating point of the fan 57, since the fan mainstream flow is operating point dependent. The ideal conditions may vary depending on the operating point for which the system is primarily designed.

[0075] In embodiments with an axially oriented suction pipe 12, the suction pipe 12 may be advantageously designed similarly to the embodiments of Figures 7 to 9, in particular if the equivalent diameter D1 at the inlet 40 of the suction pipe 12 is preferably at least twice as large as the diameter D2 at the connection 30 with the cooling pot 8, and if the outer wall of the suction pipe 12 is designed aerodynamically favorable for the main fan flow, the efficiency and pressure stability of the fan 57 via the suction pipe 12 are improved.

[0076] In an embodiment having an axially oriented intake pipe 12 similar to the embodiment of Figures 7 to 9, the advantageous diameter D2 of the intake pipe 12 at the connection 30 to the cooling pot 8 is approximately 20% to 45% of the outer diameter D of the impeller 19 of the fan 57.

[0077] FIG. 10 shows a diagram illustrating the relative improvement measured in laboratory experiments, i.e., the reduction in temperature of thermally critical electronic components as a function of the temperature difference between the fan mainstream and the pressure side ambient, for two different diameters of the inlet pipe 12. Experiments were carried out using an embodiment similar to that shown in FIGS. In this embodiment, an intake pipe 12 across the main fan flow guides cool air from the pressure side periphery to the cooling pot 8 . On the test bench, various temperature differences ΔT were set between the fan mainstream and the pressure side ambient area (ΔT = temperature (of the fan mainstream) - temperature (of the pressure side ambient area)). Furthermore, in each case a reference measurement was carried out with the same fan 57 in the same operating conditions, but without the cooling system according to the invention, more precisely without the cover of the intake pipe 12 and the cooling pot 8.

[0078] The rotation speed and operating point (volume flow rate of the main flow of the fan) of the fan 57 were set constant in all experiments. Experiments have shown that in certain thermally critical electronic components (here, IGBTs or the output stages of power electronics integrated into motors), the steady-state temperature T elCool(steady-state temperature after a sufficiently long operating time with the cooling system according to the invention) was measured. The corresponding steady-state temperatures are the same as those of the reference experiment (T elRef Since the data is also collected, the improvement due to the application of the cooling system of the present invention is elRef -T elCool It can be evaluated as follows.

[0079] Furthermore, when this improvement is related to the temperature difference ΔT between the fan mainstream and the pressure side ambient part, the thermal efficiency η of the cooling system according to the present invention, which uses the cool air from the pressure side ambient part to cool the components to be cooled, such as the fan 57, its motor 34, or its control electronics, which have a fan mainstream with a higher temperature than the pressure side ambient part, is T is η T =(T elRef -T elCool ) / ΔT. This efficiency η T represents how "efficiently" the temperature of the cold air at the pressure side periphery is utilized to cool, for example, motor components and electronic components, when the main air drawn in from the inlet nozzle 9 of the fan 57 is at a high temperature. Such efficiencies may be collected and observed equally for various locations or elements of the fan 57, motor 34 or control electronics (where temperatures are measured), and may vary even for elements or locations having the same structure.

[0080] In the experiments presented here, this efficiency η T is related to ΔT and fan impeller diameter D in a dimensionless form δ S The critical temperature of the output stage of the power electronic device was determined based on the diameter of the intake pipe 12 having a constant cross-sectional area D1, where D1 is the diameter of the intake pipe 12 and D2 is the cross-sectional area of ​​the intake pipe 12. where D1 or δ S It should be noted that the value of , a non-circular cross section of the intake pipe 12, or the use of multiple intake pipes 12 running in parallel, must set the hydraulically equivalent diameter of the total cross section of the intake pipe 12 through which flow occurs.

[0081] For example, if the pressure side ambient temperature is 30K lower than the temperature of the main fan flow, then by using the cooling system according to the present invention the temperature of the output stage will be about 15K lower, which is a significant improvement.

[0082] Furthermore, the relative diameter δ S The results when an intake pipe 12 with a flow rate of 8% is used are shown by the dashed line in the figure. In the intake pipe 12 with a smaller cross-sectional area through which the flow to the cooling pot 8 occurs, the thermal efficiency is lower in this case because less cold air flows per unit time and / or this air is already more strongly preheated as it passes through the intake pipe 12. JPEG2026506232000003.jpg16170Again, various measurement errors can affect the results, such as changes in the heat output of motor components and variations in air density.

[0083] The total cross-sectional flow area of ​​the one or more parallel-extending intake pipes 12 is not selected solely depending on the desired thermal efficiency of the cooling system. Intake pipes 12 with large cross-sectional flow areas may be more complex to manufacture, for example, due to the need to use multiple parallel intake pipes 12 . If only one large cross-sectional area intake pipe 12 is used, this intake pipe 12 may obstruct the main fan flow, at least if it extends transversely to the main flow, which may lead to, for example, a decrease in efficiency. This problem does not occur, or occurs only to a very small extent, with an axial suction pipe 12 that runs approximately parallel to the main flow in the axial extension of the cooling pot 8, as in the embodiment shown in Figures 7 to 9, for example. This is an advantage of a cooling system implemented in this way.

[0084] When a plurality of intake pipes 12 extending transversely to the main fan flow are used, the sum of the relative hydraulic equivalent diameters of the intake pipes 12 where the flow occurs is approximately δ S = 5% to δS = 20% has proven to be practical and advantageous. Considering that a laterally extending suction pipe 12 may obstruct the main fan flow, resulting in reduced efficiency, integrating the suction pipe 12 into the support vanes 3 or the inner guide vanes 11 is also a particularly advantageous option.

[0085] Furthermore, it is preferable that the intake pipe 12 be insulated as much as possible from the main flow of the fan. This minimizes preheating of the cooling air as it passes through the intake pipe 12. Therefore, the walls of the intake tube 12 are advantageously made of plastic and have a thickness of at least about 2 mm, preferably 3 mm.

[0086] The cooling system according to the invention is suitable for a wide variety of devices and also for a wide variety of fans of different designs, for example axial fans with or without guide wheels, radial fans or mixed flow fans with spiral housings or housings (flow passages) that extend further axially. The important point is that the pressure field created by the fan guides cool ambient air from the surrounding area associated with the pressure side of the fan through an intake pipe crossing the main fan flow and into a cooling pot in which the electric motor is fully or partially located and which is intended to be used for cooling the electric motor.

[0087] The presented technology is also explicitly claimed for the reverse case of temperature distribution, where the temperature of the fan main stream is very low and the motor is located on the periphery in a "cooling pot" where the ambient temperature is high.

[0088] To avoid repetition, reference is made to the general part of the description and the appended claims for further advantageous designs of the device according to the invention.

[0089] Finally, it is expressly noted that the above-described embodiments of the device according to the invention are illustrative of the claimed teachings and are not intended to limit the claimed teachings to the embodiments. [Explanation of symbols]

[0090] 1 Support guide unit 2. Support guide unit housing 3 Support blade 4 Hub ring, outer ring of cooling device pot 5. Intermediate ring of guide unit or diameter expansion area 6...outer flow area 7...Inner flow area 8. Cooling device pot 9. Inlet nozzle 10. Outer wall of the diameter expansion area 11 Inner guide element, guide vane 12. Cooling device intake pipe, intake tube 13 Stator pot, electronics housing 14...Cooling flow guide part 18. Fixing means for motor on fixing flange 19 Impeller 20. Means for fixing the guide unit on the inlet side in the host system 21. Outflow side fixing means for guide unit in upper system 22 Impeller blades 23 Suction pipe, inlet or connection of suction pipe 25. Fixing means for outlet protective grid 27 Diameter of refrigerator pot DN 29 Impeller area 30: Connection of intake pipe to cooling pot 31 Impeller hub 32 Impeller rotation direction 34 Motor 35 Motor rotor 36 Motor stator 37 Hub Food 38 Impeller blade winglets 40...Cooling device 41 Cooling channel 42 Cooling passages in the area of ​​the fixing flange 43 Refrigerator pot cover 44 Cable connection on the cooling device pot 45 Axial end area of ​​cover 46 Rotor-side receiving area in hub ring 47 Side area of ​​the cover to which the suction pipe is connected 49 Stator flange 50 Cooling ribs on the stator 51 Cooling fan wheel on rotor 53 Cable connection on motor stator or electronics housing 54 Front flange or front wall of cooling pot 56 Nozzle plate 57 Fan, axial fan 58 Reinforcing ribs in the motor receiving area 59 Motor fixing flange 63 Connection for intake pipe on cover 64 Ventilation equipment 65...heat exchanger 66...equipment wall 67 Connection for cooling circuit 68 Cooling air supply pipe 69 Equivalent inlet diameter D1 of suction pipe 70 Equivalent diameter of cooling pot D2

Claims

1. 1. A device for cooling an electric motor of a fan using air, comprising: A device for cooling an electric motor, wherein the fan generates a pressure difference between the inlet side and the electric motor and the outlet side during operation, and uses this pressure difference to guide cool ambient air from the outlet side to the electric motor.

2. 2. The apparatus for cooling an electric motor as described in claim 1, wherein the cooling in fluid operation is based solely on the flow field / pressure field generated by the fan and utilizes only the flow drive inherent to the fan.

3. a suction pipe is provided, which is designed as a suction pipe; The suction pipe fluidly connects a central region of the fan near the electric motor to a pressure-side (outlet) periphery of the fan. the pressure side (outlet side) peripheral portion is a region where the pressure associated with the outlet side of the fan is higher than that of the central region near the electric motor and where the temperature is lower than that of the main fan flow drawn in from the inlet nozzle; 3. A device for cooling an electric motor according to claim 1 or 2, characterized in that the free surrounding air, which has a lower temperature, is at least partially present at the point of entry into the intake pipe.

4. a cooling pot surrounding the electric motor or the stator and / or electronics housing of the electric motor; 4. The device for cooling an electric motor according to claim 1, wherein the cooling pot forms an at least substantially closed area toward the inlet side and radially outward, the area having a lower temperature than the main flow of the fan, in order to maintain an environment filled with cooling air, and the area is located in an area close to the shaft.

5. one or more internal cooling air paths or one or more internal cooling air regions through which the cooling air flows are formed inside the electric motor or inside an electronics pot and / or inside a stator of the electric motor; 5. The device for cooling an electric motor according to claim 1, wherein the cooling air is capable of absorbing waste heat of the electric motor in the internal cooling air path or in the internal cooling air region.

6. the intake pipe, designed as an intake pipe, fluidly connects the interior of the cooling pot or the internal cooling air path or the internal cooling air area with the pressure-side (outlet-side) periphery of the fan, the pressure side (outlet side) periphery being a region of high pressure associated with the outlet side of the fan and having a temperature lower than that of the main fan flow drawn through the inlet nozzle; 6. A device for cooling an electric motor according to claim 4 or 5, characterized in that the free surrounding air, which has a lower temperature, is at least partially present at the point of entry into the intake pipe.

7. 7. A device for cooling an electric motor according to claim 4, wherein the air used for cooling flows into the cooling pot or the internal cooling air path or area via the intake pipe from the ambient atmosphere or from free space with an appropriately controlled temperature.

8. the cooling pot, the internal cooling air path, or the internal cooling air region has an opening that opens toward the inlet side of the fan, or toward the impeller or the hub of the impeller; 8. An apparatus for cooling an electric motor as claimed in any one of claims 4 to 7, characterized in that cooling air flows out of the cooling pot or the internal cooling air path or the internal cooling air region through the opening in a forward direction, thus towards the hub of the impeller.

9. 9. A device for cooling an electric motor according to claim 4, wherein the cooling flow leaving the cooling pot or the internal cooling air path or the internal cooling air area enters the main cooling system of the electric motor via cooling ribs that dissipate heat on a flange of the stator of the electric motor.

10. the cooling pot or the internal cooling air path or the internal cooling air region is located in a downstream region of the impeller and slightly near the shaft or the hub; 10. An arrangement for cooling an electric motor according to claim 4, wherein in the downstream region the main fan flow has a significantly higher circumferential speed, resulting in a pressure field in which the static pressure radially inward, i.e., near the axis, is significantly lower than the static pressure radially outward.

11. 11. The apparatus for cooling an electric motor according to claim 10, characterized in that the pressure field has a significantly lower static pressure than the area outside the electronics housing, whereby cooling air flows through the intake pipe into the cooling pot and then out through an opening in the cooling pot to mix with the main fan flow.

12. 12. An arrangement for cooling an electric motor according to any one of claims 4 to 11, characterized in that the cooling pot and / or the suction pipe are integrated into a support structure, preferably a support and guide unit, of the electric motor and impeller of the fan.

13. a flow guide is formed in the cooling pot or in the internal cooling air path or the internal cooling air region; 13. An apparatus for cooling an electric motor according to any one of claims 4 to 12, characterized in that the flow guide guides the cooling air to pass close to a wall surface of an electronics housing or a stator to be cooled at a relatively high velocity and / or high turbulence.

14. A fan comprising a device for cooling an electric motor according to any one of claims 1 to 13.

15. 15. The fan according to claim 14, wherein the fan draws in, at the inlet side, air that has been heated or has an increased temperature by previously passing through a heat exchanger in the flow path.

16. The outlet flow has a high velocity, so that the hot air in the main flow of the fan is discharged from the fan downstream of the fan; 16. A fan according to claim 15, characterized in that hot air is not drawn in at the inlet of the suction pipe.

17. Cool ambient air is drawn directly or indirectly into the heat exchanger; the same cold air from the surrounding area, which is heated when passing through the heat exchanger and has a pressure slightly higher than that of the flow area between the heat exchanger and the fan, is directed through the intake pipe to an area close to the electric motor or the shaft, and is used to enhance the cooling effect in that area; 17. A fan according to claim 15 or claim 16, characterized in that the suction pipe fluidly constitutes a kind of bypass parallel to the flow through the heat exchanger, guiding cool ambient air directly to the electric motor of the fan.

18. 18. A method for cooling an electric motor of a fan using a device for cooling an electric motor as claimed in any one of claims 1 to 13 and / or for use in a fan as claimed in any one of claims 14 to 17.

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