Engine fan and the use of an engine fan

Abstract

Motor fan (10), wherein the motor fan (10) has a vane (12), wherein the motor fan (10) has a drive arranged in a drive housing (16), wherein a gap (24) is formed between the vane (12) and the drive housing (16), wherein an airflow drawn in by the vane (12) is guided along at least a part of the drive housing (16) before reaching the vane (12), characterized in that the motor fan (10) has a deflecting element (28) arranged in the flow direction (18) of the drawn-in airflow immediately in front of the gap (24) for deflecting the airflow.

Description

[0001] The invention relates to a motor fan and the use of a motor fan.

[0002] Motor fans of the type in question have an impeller. The impeller is set in rotation by a drive – usually electric – which is located in a drive housing. In such a motor fan, the impeller serves to convey an airflow, which is initially drawn in by the impeller. Before reaching the impeller, the airflow drawn in by the impeller is guided along at least part of the drive housing, as illustrated, for example, in JP 2013-47489 A.

[0003] One problem with the operation of such motor fans is that, under unfavorable environmental conditions, contaminants can penetrate a gap between the impeller and the drive housing. Such contaminants can impede the rotation of the motor fan's impeller. The resulting stiffness caused by friction can lead to thermal overload of the motor. In the worst case, this leads to the failure of the motor fan, which may be associated with further consequential damage due to the ventilation system failure.

[0004] According to current technology, the problem can be solved by regular maintenance or cleaning of the motor fans. However, this is labor-intensive and therefore costly. Furthermore, it can cause downtime.

[0005] Sealing the gap between the rotating impeller and the stationary motor housing usually does not lead to satisfactory results, as the rotation of the impeller is already hindered by the seal itself in such cases.

[0006] The invention is therefore based on the objective of demonstrating a motor fan and a use of a motor fan in which the problems described above do not occur or at least occur to a reduced extent.

[0007] The problem is solved by a motor fan and the use of a motor fan with the features of the independent claims. The features of the dependent claims relate to advantageous embodiments.

[0008] The illustrated and described motor fan features a deflecting element positioned in the direction of the intake airflow immediately upstream of the gap to deflect the airflow. It has surprisingly been found that such a deflecting element can deflect the airflow, which normally carries contaminants into the gap, in such a way that the deposition of contaminants in the gap can be at least significantly reduced. In this context, such a deflecting element is understood to be any element whose primary function is to deflect the airflow in the area immediately upstream of the gap. This can be a separate component. Alternatively and / or additionally, the deflecting element can also be an integral part of another component. This other component can be, in particular, the drive housing or a part thereof.

[0009] In the context of the following description, the flow direction of the airflow drawn in by the impeller is understood to be the prevailing flow direction within the fan housing, which is oriented primarily parallel to the impeller's axis of rotation. It is understood that the local flow direction will deviate from this general direction at certain points due to turbulence and similar phenomena; this applies particularly to turbulence and similar phenomena intentionally generated by the deflector. Therefore, in cases of doubt, the flow direction of the airflow drawn in by the impeller should be understood to be a direction parallel to the impeller's axis of rotation.

[0010] The deflecting element can have an annular cross-section in the direction of the intake airflow. Such an annular deflecting element is particularly well suited to deflecting the airflow in front of the slot's inlet opening, which is usually also annular.

[0011] In particular, the inlet opening of the gap can point against the direction of the intake airflow. Such a design of the motor fan is particularly susceptible to the ingress of contaminants in conventional motor fans according to the prior art, since the airflow direction through the inlet opening points into the gap. Contaminants carried by the airflow are therefore particularly easily introduced into such an oriented inlet opening. Accordingly, a deflector element positioned directly in front of the gap, and especially directly in front of the inlet opening of the gap, is particularly effective in this case.

[0012] The deflector element can have a baffle surface oriented against the direction of the incoming airflow. A baffle surface is understood here as a surface in the fluid dynamics sense. The air flowing towards the deflector element is stopped by the baffle surface and backs up in front of it. In this way, a flow around the deflector element is created.

[0013] The baffle surface can be oriented, at least substantially, perpendicular to the direction of the intake airflow. A perpendicular orientation of the baffle surface allows, in particular, the airflow to back up in front of the baffle surface. Furthermore, it causes the airflow to be deflected. Specifically, the airflow is deflected radially outwards, i.e., away from the inlet opening of the gap. An orientation that is at least substantially perpendicular here refers to a baffle surface that is not exactly perpendicular to the direction of the intake airflow, but rather forms an angle to it large enough to produce the desired effect of backing up and deflecting the airflow.

[0014] In particular, the deflecting element can have a separation edge oriented in the direction of the intake airflow. This refers to a separation edge in the fluid dynamics sense, meaning an edge behind which turbulence develops due to flow separation. It has been shown that such a separation edge, oriented in the direction of flow, can have a positive effect on preventing dirt from entering the gap.

[0015] The airflow drawn in by the impeller can be guided along a surface area of ​​the drive housing adjacent to the gap before reaching the impeller. This surface area can, in particular, transition smoothly into a surface area that forms a drive housing-side boundary of the gap, or in other words, form a common surface area with this surface area. The surface area can be cylindrical, especially circular cylindrical. A substantially cylindrical, especially circular cylindrical, design is also conceivable in this context. In this case, the surface area has a circular cylindrical shape over the majority of its circumference, while a geometrically different shape is chosen for certain sections in the circumferential direction. This can be done, for example, to accommodate screw connections or similar features.

[0016] The surface area can also have a conical shape, particularly one that tapers towards the fan. Curved shapes, where the surface area forms or defines a solid of revolution, are also possible. Designs are also possible where the surface area essentially forms or defines a solid of revolution. This means, in particular, that the surface area forms a solid of revolution over a predominant part of its circumference, while a different design is chosen in certain areas, for example, to allow for screw connections.

[0017] The deflecting element can form a projection, particularly relative to this surface area. In this context, the deflecting element can be designed in a ring shape. It has been shown that reliable function of the deflecting element is possible, in particular, if it protrudes from the surface area by at least 3 mm, in particular at least 4 mm, and / or at most 11 mm, in particular at most 10 mm.

[0018] Furthermore, it has been shown that the functionality of the deflecting element is reliably ensured, in particular, when it protrudes from the surface area by at least 80%, in particular at least 90% and / or at most 120%, in particular at most 110% of the width of the gap at its entry opening.

[0019] Furthermore, it has been shown that reliable functioning of the deflection element is ensured in particular when it extends along the flow direction of the aspirated airflow over at least 2 mm, in particular at least 3 mm and / or at most 7 mm, in particular at most 6 mm.

[0020] Furthermore, it has been shown that reliable function of the deflection element is ensured in particular when the distance between the deflection element and the inlet opening is at least 1 mm, in particular at least 2 mm and / or at most 6 mm, in particular at most 5 mm.

[0021] Furthermore, it has been shown that a reliable function of the deflecting element is ensured in particular when it is spaced at least 10%, in particular at least 20% and / or at most 100%, in particular at most 90% of the width of the gap at its inlet opening from the air inlet opening.

[0022] The deflector element is particularly suitable for preventing the ingress of contaminants into the gap when the impeller surrounds an end region of the drive housing. In such a case, the gap can extend, at least substantially, in a hollow cylindrical shape around the end region of the drive housing. In this case, the direction of penetration of the dirt particles is parallel, or at least substantially parallel, to the flow direction of the intake air. This allows the dirt particles to penetrate the gap particularly easily and deeply without the use of a deflector element; consequently, the deflector element is especially effective in such a case. An extension that is at least substantially hollow cylindrical is understood to mean, in particular, an extension in which only a portion of the gap forms a hollow cylinder.in which the hollow cylinder narrows and / or widens along the direction of airflow, as long as the resulting conical structure is still oriented at such a shallow angle to the direction of airflow that the dirt particles are not significantly hindered in their penetration into the gap by this narrowing or widening.

[0023] The deflection element is particularly useful when the gap connects the airflow path to a cavity located between the fan wheel and the drive housing. In such a cavity, contaminants can accumulate over a relatively long period before problems arise with the fan. The cavity differs from the gap primarily in that it provides a comparatively large volume in which contaminants can accumulate. This is because the gap—by its very nature—has only a small dimension in one direction. However, if sufficient contaminants, which have previously passed through the gap, have accumulated in such a cavity, a significant impairment of the impeller's rotation relative to the drive housing occurs in a short period of time. This results in the comparatively serious scenarios of impaired motor fan function described above.

[0024] The deflector element is particularly beneficial when the motor fan is used in textile production and / or processing. In such environments, the ambient air is naturally contaminated with textile fibers. These fibers can be carried along by air currents. Such textile fibers can have a particularly detrimental effect on the operation of a motor fan if they become entangled around the shaft connecting the impeller to the drive. The fibers can then form veritable threads that can even be drawn into the shaft's bearings. It has been shown that the deflector element is especially effective at keeping contaminants originating from textile fibers away from the gap.

[0025] Further practical embodiments and advantages of the invention are described below in connection with the drawings. They show: Fig. 1 a schematic longitudinal section view of an exemplary motor fan according to the state of the art, Fig. 2 the in Fig. 1. Motor fan shown with a deflector element, Fig. 3 an enlarged sub-area from Fig. 2, Fig. 4 an alternative embodiment of a motor fan according to the prior art, Fig. 5. Turn off the engine fan Fig. 4 with a deflection element, Fig. 6 an enlarged sub-area from Fig. 5

[0026] The in Fig. An exemplary motor fan 10 has an impeller 12 for conveying the airflow. The impeller 12 is driven by a drive, for example an electric motor 14, which is arranged in a drive housing 16. The impeller 12 conveys an airflow that is drawn in by the impeller 12 along the direction 18, which is oriented parallel to the axis of rotation 20 of the impeller. The drive housing 16 and the impeller 12 are arranged in a common housing 22, which also serves, in particular, to channel the airflow conveyed by the impeller 12.

[0027] At the in Fig. In the prior art fan shown in Figure 1, a gap 24 forms between the fan 10 and the drive housing 16. The gap 24 connects the flow path of the airflow conveyed by the impeller 12 with the cavity 26, which is formed between the impeller 12 and the drive housing 16.

[0028] During operation of the exemplary motor fan 10, contaminants can penetrate through the gap 24 into the cavity 26. In the example shown, this is facilitated by the fact that the inlet opening of the gap 24 points against the flow direction 18 of the airflow drawn in by the impeller 12.

[0029] The one in Fig. The motor fan shown in the diagram 10 differs from the one in the diagram. Fig. The motor fan 10 shown in Figure 1 is improved according to the prior art, in particular by the fact that the motor fan 10 has a deflecting element 28. The deflecting element 28 deflects the airflow drawn in by the impeller 12. Since the deflecting element 28 is arranged in the flow direction 18 of the drawn-in airflow immediately in front of the gap 24, the deflection of the airflow significantly reduces the entry of contaminants into the gap 24.

[0030] As can be seen from the enlarged view in Fig. As can be seen from Figure 3, the deflecting element 28 in the example shown can have a separation edge 30 oriented in the flow direction 18 of the aspirated airflow and / or a baffle surface 32 oriented against the flow direction 18 of the aspirated airflow. The deflecting element 28 can be designed in an annular shape, as in the example shown. It can also form a projection, as in the example shown, relative to a surface area 34 along which the airflow aspirated by the impeller 12 is guided before reaching the impeller 12.

[0031] The surface area 34 can, as in the example shown, border the gap 24 and / or have a substantially circular cylindrical shape.

[0032] In Fig. 4 shows another exemplary motor fan 10, which also corresponds to the one shown in the Fig. 1, Fig. 2 to Fig. The motor fan shown in 3 has the 10 features described in the 3. The one in Fig. In the exemplary motor fan 10 shown in Figure 4, the impeller 12 is surrounded by an end region 36 of the drive housing 16. The gap 24 can extend around the end region 36 in a hollow cylindrical shape, as in this example. This hollow cylinder can, as in the example shown, have an orientation parallel to the direction 18 of the airflow drawn in by the impeller 12.

[0033] If such a fan, as in the Fig. 5 and Fig. As shown in Figure 6, which has a deflecting element 28, the ingress of contaminants into the gap 24 is significantly reduced. Reference symbol list 10 motor fans 12 impeller 14 Electric motor 16 drive housings 18 Direction of airflow 20 Rotation axis 22 cases 24 columns 26 cavity 28 Deflection element 30 Tear-off edge 32 Impact area 34 Surface area 36 End range

Claims

[1] Motor fan (10), wherein the motor fan (10) has a vane (12), wherein the motor fan (10) has a drive arranged in a drive housing (16), wherein a gap (24) is formed between the vane (12) and the drive housing (16), wherein an airflow drawn in by the vane (12) is guided along at least a part of the drive housing (16) before reaching the vane (12), characterized by , that the motor fan (10) has a deflecting element (28) arranged in the direction of flow (18) of the aspirated airflow immediately in front of the gap (24) for deflecting the airflow. [2] Motor fan (10) according to claim 1, characterized by , that the deflecting element (28) has an annular cross-section in the direction of flow (18) of the aspirated airflow. [3] Motor fan (10) according to claim 1 or 2, characterized by, that the inlet opening of the gap (24) points against the direction of flow (18) of the aspirated airflow. [4] Motor fan (10) according to any of the preceding claims, characterized by , that the deflecting element (28) has a baffle surface (32) oriented against the direction of flow (18) of the aspirated airflow, in particular wherein the baffle surface (32) is oriented perpendicular to the direction of flow (18). [5] Motor fan (10) according to any of the preceding claims, characterized by , that the deflecting element (28) has a separation edge (30) oriented in the direction of flow (18) of the aspirated airflow. [6] Motor fan (10) according to any of the preceding claims, characterized by , that an airflow drawn in by the impeller (12) is guided along a surface area (34) of the drive housing (16) which is adjacent to the gap (24) before reaching the impeller (12). [7] Motor fan (10) according to claim 6, characterized by, that the deflecting element (28) forms a projection relative to this surface area (34). [8] Motor fan (10) according to any of the preceding claims, characterized by , that the impeller (12) surrounds an end region (36) of the drive housing (16), in particular wherein the gap (24) extends in a hollow cylindrical shape around the end region (36). [9] Motor fan (10) according to any of the preceding claims, characterized by , that the gap (24) connects the airflow path with a cavity (26) arranged between the impeller (12) and the drive housing (16). [10] Use of a motor fan (10) according to one of the preceding claims in a textile production and / or textile processing.

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