EP2559905B1 - Engine mount for ventilators, preferably axial ventilators, and method for producing a ventilation grill of such an engine mount - Google Patents

Description

The invention relates to a motor mounting for fans, preferably axial fans, according to the preamble of claim 1 and a method for producing a ventilation grille of such a motor mounting according to the preamble of claim 11.

Motor suspensions are known, the ventilation grilles of which have coaxial grille rings which are connected to one another by radially extending struts ( DE 10 2009 025 025 A . DE 23 45 539 A . DE 101 11 397 A . DE 197 53 373 A ). The radially inner ends of the struts are either designed as fastening elements for connection to the motor or connected to a fastening disk which is connected to the fan. The radially outer end of the struts has holding elements ( DE 101 11 397 A ), which are used to hold connecting means with the fan. The ventilation grilles have straight areas in axial section, the radially inner and outer areas being inclined in opposite directions to one another and connecting at an obtuse angle to a straight central area. Such ventilation grilles can only be produced in a complex manner, since a separate welding device and therefore also a separate welding process is required for each of these grille areas.

Since noises can occur during operation of the fan, it is known to produce the radially extending struts from flat profiles, which are inclined to the longitudinal axis of the fan in accordance with an average swirl component ( DE 10 2009 025 025 A ). It is also known that the sections located between the radially outer and radially inner ends of the support struts from the plane of the flat profile, so that the edges connected to the grid rings are preserved as a straight line. However, this makes the manufacture and construction of the ventilation grille very complex.

It is also known to avoid flow-related noises ( DE 197 53 373 A ) to design the ventilation grille in the manner of an air guide wheel with blade-like guide webs, which extend over a certain axial air duct length and are essentially arranged radially. The guide bars are arranged in at least two concentric rows of circles, the number of guide bars in the outer row being greater than in the adjacent inner row of circles. Such a design of a ventilation grille is also structurally very complex, which increases the cost of manufacturing the ventilation grille.

It is also known after all ( DE 101 11 397 A ), put a comb-like damping agent on the coaxial lattice rings.

In the generic state of the art ( EP 1 120 571 A1 ) the fan is arranged inside a housing and attached to a housing wall. The housing has an air outlet opening that is covered by a ventilation grille that is attached to the outside of the housing. To reduce the acoustic noise of the fan, the number of struts is varied with regard to the number of fan blades.

It is also known ( DE 20 2007 012 704 U1 ) to provide a low-vibration fan with a frame construction for fastening a coil module and for driving an impeller. The fan has a lower part with a disc body, from which a plurality of projecting ribs extend outwards, which are connected to a frame body via elastic suspension arms. The fan is connected to the disc body which, together with the elastically deformable suspension arms, forms an elastic frame.

It is also known ( DE 693 33 845 T2 ) to provide an axial fan with a cover construction. The fan is provided with a cover element which has a part which surrounds the fan and which is shaped in such a way that it can interact with an outer ring. A ventilation grille to protect the fan is not provided.

The object of the invention is to design the generic motor suspension and the generic method in such a way that optimum noise and vibration reduction during operation of the fan is achieved in a structurally simple and cost-effective manner.

This object is achieved according to the invention with the generic engine suspension with the characterizing features of claim 1 and with the generic method according to the invention with the characterizing features of claim 11.

In the engine mounting according to the invention, the number and / or the diameter (cross section) of the struts is varied with a view to reducing the acoustic noise and / or the natural resonances of the engine mounting in order to adapt to the vibration behavior of the fan. By varying the number of struts and / or the diameter of the struts, it is thus possible in a simple manner to adapt the engine suspension to the respective application in such a way that the acoustic noises occurring during operation are minimal and / or the occurrence of natural resonances of the engine suspension is avoided.

This adjustment can be carried out particularly easily since the struts are fastened with their radially outer end to an outer support ring. This makes it easy to attach the desired number of struts to the ventilation grille.

The inner support ring has a flat ring part lying in a radial plane of the ventilation grille, the edge of which is directed obliquely upwards. The radially inner ends of the struts are attached to the upward edge of the inner support ring. The struts then connect the outer support ring to the inner support ring. Via the inner support ring, the ventilation grille can be easily connected to the fan regardless of its mounting division. Since the outer support ring and the inner support ring are designed to run all the way around and the inner support ring is set up, the struts can be attached at any suitable point on the ventilation grille and connected to the outer support ring and the inner support ring.

In one embodiment, in order to reduce the noise during operation of the fan, the number of struts, which are preferably made of metal, is selected such that it is not equal to the number of blades of the fan. This allows the ventilation grille to be optimally matched to the fan used in each case with regard to noise reduction.

A cost-effective and simple design results if the outer support ring has a cylindrical outside to which the radially outer ends of the struts are attached.

The outer support ring advantageously consists of flat material. It is advantageously formed from a strip that is bent into a cylinder. In this way, the outer support ring can be manufactured very easily in any required diameter.

In another embodiment, the outer support ring can consist of a flat material that lies in a radial plane of the ventilation grille. This also ensures simple manufacture of the outer support ring. The ends of the struts can be easily attached to the flat outer support ring.

The outer support ring does not have to be made of a flat material. It can also be formed from at least one, but preferably from a plurality of grating rings. With the grille rings as the outer support ring, a simple and inexpensive manufacture of the ventilation grille and thus the engine mounting is also possible. The lattice rings forming the outer support ring can lie next to one another at a distance in a radial plane. However, it is also possible for lattice rings with the same diameter to be arranged one above the other so that they form a quasi-cylindrical outer support ring.

The radially outer ends of the struts are bent in an advantageous manner. Then the ends can be easily attached to the outer support ring.

The radially outer strut ends are securely fastened if the radially outer ends of the struts do not protrude beyond the outer support ring. In an advantageous embodiment, the length of the strut ends is shorter than the axial height of the outer support ring. This allows the strut ends to be attached to the outer support ring over their entire length.

The motor suspension is advantageously designed such that when the outer support ring is used, the motor suspension can be carried out individually and independently of the fastening division of the customer interface. Via the customer interface, the motor suspension or the outer support ring is attached to a wall ring that contains the nozzle for the fan. The customer interface can be formed, for example, by bores in the edge area of the nozzle of the wall ring, through which screws or the like are inserted, with which the outer support ring, which is placed on the nozzle, can be connected to the nozzle. In such a case, the outer support ring is screwed to the nozzle radially.

With the advantageous use of the inner support ring, the motor mounting can be carried out individually and independently of the fastening pitch of the fan. The radially inner ends of the struts are in this case advantageously attached to the raised edge of the inner support ring, while the interface for connection to the fan is located outside of this raised edge.

The ventilation grille can have a curved shape in axial section. This makes it possible to weld the ventilation grille in a single device in a single operation. The ventilation grille and thus the engine mounting can be manufactured very inexpensively and easily.

Advantageously, the struts, which are preferably made of metal, are curved in a convex manner over their length. The lattice rings, which are connected to each other by these struts, thus form an arched ventilation grille in the outline, which, seen in axial section, no longer has any straight areas, but runs curved over its radial width.

Some of the struts advantageously protrude radially inwards and / or outwards via the lattice rings.

The protruding ends of these struts are advantageously provided with connections with which the ventilation grille can be fastened, for example, to a wall ring and to the fan.

Some of the ventilation grille struts may have a length that is less than the radius of the ventilation grille. These shorter struts can have the same length, but also different lengths. By appropriate selection of the length and / or the cross section of these struts, the motor suspension can be matched to the vibration behavior of the fan in such a way that the acoustic noises occurring during operation are minimized and / or no natural resonances of the motor suspension occur.

Since the longer struts are used to connect the ventilation grille to a wall ring and the fan, for example, they advantageously have a larger cross section than the short struts.

The method according to the invention is carried out in such a way that the number and / or the cross section of the struts is varied with a view to reducing the acoustic noise and / or the displacement of the natural resonances of the engine suspension in order to reduce the acoustic noises and / or the displacement of the natural resonances of the engine suspension , This makes it very easy to adapt the motor suspension to the vibration behavior of the fan. To produce the ventilation grille, a welding device is used which has an outer ring to which upright, radial struts are connected, which has a curved end face with depressions one behind the other with a small spacing. The struts are arranged so that the depressions lie on a circle. The grid rings are placed in the recesses. The struts of the ventilation grille to be manufactured are then welded to the grille rings.

It is also possible, for example, to choose the number of struts so that it is not equal to the number of blades of the fan. For example, if the fan has four blades, the ventilation grille has a different number of struts. Depending on the size and / or location of the fan, it is very easy to determine the optimal number of struts. In this way, not only can the acoustics, especially the rotary sound of the fan, be reduced, but also a possible natural oscillation frequency of the motor suspension can be counteracted. The selected number of struts enables the components of the engine suspension according to the invention to be coordinated with one another in such a way that the noise and / or the natural resonances of the engine suspension are minimized.

The number of struts does not necessarily have to be different from the number of blades of the fan. Rather, it is crucial that the number of struts and / or their diameter is selected so that the desired and described adaptation of the motor suspension is matched to the vibration behavior of the fan.

A simple procedure results if the radially outer ends of the struts are attached to an outer support ring. The outer support ring enables the number of struts to be varied individually, in particular regardless of the fastening division of the customer interface.

A simple and inexpensive production is possible if the radially outer ends of the struts are attached to the outside of the outer support ring.

Further features of the invention result from the further claims, the description and the drawings.

Fig. 1

in perspektivischer Darstellung eine erfindungsgemäße Motoraufhängung,

Fig. 2

eine Draufsicht auf die Motoraufhängung gemäß Fig. 1,

Fig. 3

in vergrößerter Darstellung einen Axialschnitt durch die erfindungsgemäße Motoraufhängung,

Fig. 4

in perspektivischer Darstellung die mit einem Ventilator verbundene Motoraufhängung gemäß den Fig. 1 bis 3,

Fig. 5

in perspektivischer Darstellung eine zweite Ausführungsform einer erfindungsgemäßen Motoraufhängung,

Fig. 6

in perspektivischer Darstellung die Motoraufhängung gemäß Fig. 5, die an einem Wandring befestigt ist,

Fig. 7

in perspektivischer Darstellung eine dritte Ausführungsform einer erfindungsgemäßen Motoraufhängung,

Fig. 8

in vergrößerter Darstellung einen Axialschnitt durch die Motoraufhängung gemäß Fig. 7,

Fig. 9

in perspektivischer Darstellung eine vierte Ausführungsform einer erfindungsgemäßen Motoraufhängung,

Fig. 10

in vergrößerter Darstellung einen Axialschnitt durch die Motoraufhängung gemäß Fig. 9,

Fig. 11

in perspektivischer Darstellung eine fünfte Ausführungsform einer erfindungsgemäßen Motoraufhängung,

Fig. 12

in vergrößerter Darstellung einen Axialschnitt durch die Motoraufhängung gemäß Fig. 11,

Fig. 13

in perspektivischer Darstellung eine sechste Ausführungsform einer nicht erfindungsgemäßen Motoraufhängung,

Fig. 14

eine Unteransicht der Motoraufhängung gemäß Fig. 13,

Fig. 15

in vergrößerter Darstellung einen Axialschnitt durch die Motoraufhängung gemäß Fig. 13,

Fig. 16

in perspektivischer Darstellung die Motoraufhängung gemäß Fig. 13, die an einem Wandring befestigt ist,

Fig. 17

im Axialschnitt eine Vorrichtung zum Schweißen eines Lüftungsgitters der erfindungsgemäßen Motoraufhängung,

Fig. 18

in einer Darstellung entsprechend Fig. 17 eine bekannte Vorrichtung zum Schweißen eines Lüftungsgitters nach dem Stand der Technik,

Fig. 19

in einem Diagramm den Wirkungsgrad eines Motors mit der erfindungsgemäßen Motoraufhängung in Abhängigkeit von der Drehzahl des Ventilators.

The invention is explained in more detail with the aid of some exemplary embodiments shown in the drawings. Show it

Fig. 1

a perspective view of an engine suspension according to the invention,

Fig. 2

a plan view of the engine mount according to Fig. 1 .

Fig. 3

an enlarged view of an axial section through the engine mount according to the invention,

Fig. 4

in a perspective view the motor suspension connected to a fan according to the 1 to 3 .

Fig. 5

a perspective view of a second embodiment of an engine suspension according to the invention,

Fig. 6

in a perspective view the engine suspension according to Fig. 5 which is attached to a wall ring,

Fig. 7

a third embodiment of a motor suspension according to the invention,

Fig. 8

in an enlarged view an axial section through the engine mount according to Fig. 7 .

Fig. 9

a fourth embodiment of a motor suspension according to the invention in perspective view,

Fig. 10

in an enlarged view an axial section through the engine mount according to Fig. 9 .

Fig. 11

a fifth embodiment of a motor suspension according to the invention in perspective view,

Fig. 12

in an enlarged view an axial section through the engine mount according to Fig. 11 .

Fig. 13

a perspective view of a sixth embodiment of a motor suspension not according to the invention,

Fig. 14

a bottom view of the engine mount according to Fig. 13 .

Fig. 15

in an enlarged view an axial section through the engine mount according to Fig. 13 .

Fig. 16

in a perspective view the engine suspension according to Fig. 13 which is attached to a wall ring,

Fig. 17

in axial section a device for welding a ventilation grille of the engine mount according to the invention,

Fig. 18

in a representation accordingly Fig. 17 a known device for welding a ventilation grille according to the prior art,

Fig. 19

in a diagram the efficiency of a motor with the motor suspension according to the invention as a function of the speed of the fan.

The engine mounting is for a fan 11 ( Fig. 4 ), preferably an axial fan, is provided and has a ventilation grille 1 which has grating rings 2 which run coaxially to one another. They advantageously have the same distance from one another, according to the plan view Fig. 2 seen. The grid rings 2 advantageously have a circular cross section ( Fig. 3 ) and are advantageously made of metal. Depending on the application, the grid rings 2 can also have a cross-section deviating from a circular shape.

In the preferred embodiment shown, all the grille rings 2 of the ventilation grille 1 have the same cross-sectional area. However, it is also possible for the individual grille rings to have a different cross section, depending on the position within the ventilation grille 1.

The grid rings 2 are connected to one another by radially extending struts 3. They are also advantageously made of metal. They can also consist of wires with a circular cross section, but can also be designed as profile-shaped struts. The shape of the struts 3 over their length determines the shape of the ventilation grille 1. The struts 3 are curved convexly over their length, as a result of which the ventilation grille 1 is a has a domed shape. The struts 3 can be curved evenly over their length. However, it is advantageous if the struts 3 have a smaller radius of curvature in the radially inner region of the ventilation grille 1 than in the radially outer region. The ventilation grille therefore drops more in the radially inner area than in the radially outer area ( Fig. 1 and 3 ).

As the Fig. 1 and 3 show, the struts 3 are attached to the outside of the grille rings 2, that is, on the side of the grille rings facing away from the fan. If the struts and the lattice rings are made of metal, they are welded together at the crossing points.

The struts 3 give the ventilation grille 1 high stability and strength.

The radially inner ends 4 ( Fig. 3 ) the struts 3 are angled in the direction of the fan 11 and attached to an inner support ring 5. It has a flat ring part 6 lying in a radial plane of the ventilation grille 1, the edge 7 of which is directed obliquely upwards. The strut ends 4 are attached to the outside of the inner support ring edge 7. The ring part 6 has openings 8 distributed over its circumference. The fan 11 is fastened to the ring part 6 of the inner support ring 5 in a known manner.

The radially outer ends 9 of the struts 3 are attached to the outside of an outer support ring 10. It lies coaxial to the axis of the ventilation grille 11. As from Fig. 3 emerges, the ring part 6 is axially offset in the direction of the fan 11 from the outer support ring 10, which, viewed in the axial direction, is at a greater distance from the fan 11 than the ring part 6 of the inner support ring 5. The inner support ring 5 and the outer support ring 10 are advantageously made of metal. The struts 3 can then, if they preferably consist of metal, be simply attached by a welding process.

In order to reduce the acoustics, in particular the rotary tone of the fan 11, a grating concept with a variable and / or asymmetrical number of struts 3 is used. For example, by changing the number of struts 3 and / or by changing the cross-section of the strut, the overall system of engine mounting and fan 11 can be easily and inexpensively detuned so that the vibration values are low, which will be described in more detail below. For example, the number of struts 3 can be chosen to be unequal to the number of blades 12 of the fan 11, regardless of the interfaces to the outer support ring 10 and the inner support ring 5. By the number of struts 3 depending on the number of fan blades 12 of the fan 11 used To be able to vary, the outer support ring 10 is used to fasten the struts 3 with their radially outer end 9, which is angled so that it can be attached flat to the outside of the outer support ring 10. The outer support ring 10 preferably consists of a flat material, which is preferably bent into an upright ring. The different number of struts 3 can be easily attached to the outer support ring 10, so that the motor suspension can be matched to the fan 11 used and its number of blades in a simple manner and regardless of the interfaces to the outer and inner support ring, in order to minimize the development of noise.

The number of struts 3 can additionally be selected so that a possible natural vibration frequency of the engine suspension is avoided.

Because of the design described, there is the possibility of coordinating the components of the engine suspension, that is to say the ventilation grille 1 with the struts 3 and the outer support ring 10, in such a way that not only the rotational tone is reduced or even avoided, but also the occurrence of vibrations of the engine suspension as a result is prevented by resonances.

With the curved ventilation grille 1, the efficiency of the engine is also improved. Fig. 19 shows the course of the efficiency depending on the speed of the fan or the volume flow q _v . The solid line applies to the curved ventilation grille and the dashed line to the conventional ventilation grille, which consists of grating areas that are flat in axial section and at an angle to each other. The motors with the curved ventilation grilles have a higher efficiency than the conventional motors.

So that the ends 9 of the struts 3 can be easily attached to the outer support ring 10, at least its outside is a smooth cylindrical surface. The strut ends 9 are shorter than the height of the outer support ring 10. It is in principle possible to fasten the strut ends 9 to the outside of the outer support ring 10 with the aid of fastening means such as screws, bolts and the like. Such an attachment can also be provided in addition to a welded connection between the strut ends 9 and the outer support ring 10. Deviating from the exemplary embodiment shown, the length of the strut ends 9 can also be equal to the height or even greater than the height of the outer support ring 10. The strut ends 9 are in any case attached to the outer support ring 10 in such a way that they do not, based on the illustration according to FIG Fig. 3 , protrude downward over the outer support ring 10.

The grid rings 2 are spaced from one another such that they do not or only slightly hinder the passage of air. In addition, the distance is selected so that users cannot reach through the ventilation grille 1 by hand and come into contact with the impeller of the fan 11. The outer support ring 10 can be connected radially or axially in any division, based on the interface (nozzle). The connection of the inner support ring 5 can take place without taking into account the interface to the fan 11. This is explained in more detail below.

The ventilation grille 1 with the outer support ring 10 is placed on the free edge of a nozzle 13 ( Fig. 4 ), which protrudes from a plate-shaped wall ring 14. In the area of the nozzle 13, the impeller of the fan 11 with the blades 12 is arranged in a known manner. The outer support ring 10 is fastened with radially extending screws 15 to the free edge of the nozzle 13. The nozzle 13 forms the customer interface. The engine mounting can be carried out individually and independently of the mounting division of the customer interface due to the design described. The angular distance of the screws 15 over the circumference of the outer support ring 10 is specified by the customer. The struts 3 can be provided independently of this customer-specified distribution of the screws 15 in such a way that the development of noise is minimized and a resonance point in the operating area of the engine suspension is reliably avoided.

Since the radially outer ends 9 of the struts 3 are fastened to the outside of the outer support ring 10, the ventilation grille 1 with the outer support ring 10 can be placed correctly on the free edge of the nozzle 13.

The embodiment according to Fig. 5 is essentially the same as the embodiment according to the 1 to 4 , The only difference is that the outer support ring 10 is screwed axially to the wall ring 14 ( Fig. 6 ). For this purpose, transversely projecting tabs 16 are provided on the outer support ring 10, which are distributed over the circumference and rest in the installed position on the wall ring 14 and are connected to it by means of the screws 15. The straps 16 protruding radially from the outer support ring 10 lie in the region below the free ends of the strut ends 9. As a result, even with such an axial connection of the motor suspension to the wall ring 14, it is possible to design the motor suspension individually and independently of the division of the straps 16. The number of struts 3 can thus again be chosen without regard to the design of the customer interface so that the ventilation grille 1 is optimized with regard to noise reduction and the avoidance of natural resonances of the engine suspension.

The described design of the inner support ring 5 also makes it possible to carry out the motor suspension individually and independently of the fastening division of the fan 11. The openings 8 in the ring part 6 of the inner support ring 5 can have any distribution which does not affect the fastening of the radially inner ends 4 of the struts 3. In the two described embodiments, these strut ends 4 are located on the outside of the raised edge 7 of the inner support ring 5.

In the embodiment according to the Fig. 7 and 8th the outer support ring 10 is formed, for example, by two coaxial lattice rings 2 'which are spaced apart and on which the angled ends 9 of the struts 3 are fastened. In contrast to the previous exemplary embodiments, the strut ends 9 extend approximately horizontally, as shown in FIG Fig. 8 seen. The strut ends 9 are advantageously welded onto the grid rings 2 '. Depending on the length of the strut ends 9, the outer support ring 10 can also consist of only one or more than two lattice rings 2 '.

So that the ventilation grille 1, for example on a wall ring 14 ( Fig. 6 ) can be fastened, the outer grating ring 2 'has connections 16' arranged uniformly distributed over its circumference, which are formed by parts of the grating ring 2 'deformed radially outward. The outer lattice ring 2 'is shaped outwards in such a way that the connection 16' has two wire sections 31, 32 lying parallel to one another, which run approximately radially outwards and merge into one another in an arc shape and arcuately into the lattice ring 2 '. Disks 22 are fastened between the wire sections 31, 32, through which the fastening screws 15 ( Fig. 6 ) protrude, with which the ventilation grille 1 is attached to the wall ring 14.

The ventilation grille is in accordance with the Fig. 7 and 8th designed the same as in the previous embodiments.

The described embodiment according to the Fig. 7 and 8th shows that the outer support ring 10 does not necessarily have to be formed from a flat material, but that lattice rings 2 'can also be used for fastening the outer strut ends 9.

In the embodiment according to the Fig. 9 and 10 the outer support ring 10 is in turn formed by a flat material, which, however, in contrast to the embodiments according to FIGS 1 to 6 is not arranged upright, but lying down. On the top of the outer support ring 10, the angled ends 9 of the struts 3 are attached. On the underside of the outer support ring 10, the tabs 16 are arranged distributed over the circumference, which protrude radially outward beyond the outer support ring 10 and with which the ventilation grille 1 is fastened to the wall ring 14 in the manner described. The strut ends 9 protrude slightly radially outwards over the outer support ring 10, on which they are fastened along their length in the manner described. The length of the strut ends 9 can of course be the same size or less than the radial width of the outer support ring 10.

Otherwise, the ventilation grille is of the same design as in the previous embodiments.

The ventilation grille 1 according to the Fig. 11 and 12 in turn has the raised outer support ring 10, which, however, in contrast to the embodiments according to FIGS 1 to 6 is not formed from flat material, but from grid rings 2 'arranged one above the other. In the exemplary embodiment shown, the outer support ring 10 is formed by four grid rings 2 'which are spaced one above the other and have the same outer diameter and on the outside of which the ends 9 of the struts 3 are fastened. Depending on the embodiment, the outer support ring 10 can also consist of fewer or more grid rings 2 '.

Connections 16 ″, of which are arranged in a uniformly distributed manner, are provided over the circumference of this outer support ring 10 Fig. 11 only one connection is visible. The connections 16 ″ are each formed by washers 22 which extend with an attachment between two adjacent grille rings 2 ′ and are held between them. The fastening screws, with which the ventilation grille 1 is fastened to the fan, project through the washers 22 as in the embodiment according to the 1 to 4 radial with respect to the ventilation grille 1.

The ventilation grille is in accordance with the Fig. 11 and 12 designed the same as the embodiments according to the 1 to 6 ,

The ventilation grille concept, which is based on the exemplary embodiments according to the 1 to 12 has been explained, enables optimum noise optimization during use in that the number of struts 3 can be designed variably and / or in an asymmetrical distribution. The struts 3 can thus be optimally provided on the ventilation grille 1 in such a way that the noise development when using the fan equipped with the ventilation grille is minimal. The vibration values can be achieved in a simple manner by changing the number of struts and / or by arranging the ventilation grille accordingly. The detuning can also be optimally adjusted by appropriately adapting the cross section of the struts and / or together with the number of struts. Tests have shown that the vibration values can be changed significantly by changing the cross section of the fastening struts 17. If the variation in the number of fastening struts 17 is also used here, the vibration values can be adapted excellently to the respective application. In addition, this coordination of the vibration values can be carried out inexpensively. This measure also does not increase the weight of the ventilation grille 1.

With the engine mounting according to Fig. 13 an inner support ring and an outer support ring are not provided. The engine mount has the grating rings 2 and the radially extending struts 3. They are in turn arcuately convex along their length and extend from the radially outermost grating ring 2. In contrast to the previous exemplary embodiments, the struts 3 do not extend over the entire radial width of the ventilation grille 1, but end at a distance from the radially inner grille ring 2. For fastening the ventilation grille 1 to the wall ring 14 ( Fig. 16 ) and on the (not shown) fan fastening struts 17 are provided, which are convexly curved over their length and, like the struts 3, are fastened on the side of the grille rings 2 facing away from the fan. The ends of the fastening struts 17 project radially over the outer and the inner grille ring 2. As in the previous embodiments, the fastening struts 17 are provided, for example, at 90 ° angles on the ventilation grille 1.

The fastening struts 17 are advantageously formed by a hairpin-shaped lattice bar, the two legs 18, 19 of which run parallel to one another and merge into one another at the radially outer end of the fastening strut 17.

The radially outer and inner ends 20, 21 of the fastening struts 17 are angled such that the ventilation grille 1 can be attached to the wall ring 14 or to the fan in a suitable manner. On the ends 20, 21, a washer 22, 23 is fastened, through which the fastening screws 15 protrude, with which the ventilation grille 1 is fastened to the wall ring 14 or to the fan.

The fastening disks 22, 23 at both ends of the fastening struts 17 are each at the same height. How Fig. 15 shows, the disks 23 on the radially inner end of the fastening struts 17 are, however, axially offset from the disks 22 on the radially outer end of the fastening struts. The ventilation grille 1 is fastened on the wall ring 14 via the disks 22. The radially inner disks 23 are spaced from the wall ring 14.

Due to the curved design, the ventilation grille 1 can be welded in one operation using a welding device. The welding device has an outer ring to which upright, radially extending struts are connected. Of these struts is in Fig. 17 only one strut 24 shown. It has a concavely curved end face 25, in which depressions 26 which are located one behind the other are provided at a short distance. They are only a short distance apart. The struts of the device are arranged so that their depressions are each on a circle. The grille rings 2 of the ventilation grille 1 to be produced are inserted into the depressions 26 of the struts 24. In the exemplary embodiment, there is a grille ring 2 in each recess 26. Depending on the design of the ventilation grille 1, the grille rings 2 can, for example, only be inserted into every second recess 26 or at irregular intervals. With the help of the upright struts 24, the struts 3, 17 of the ventilation grille 1 can then be welded to the grille rings 2. Since the struts 24 are arranged uniformly distributed over the circumference of the device and are at a relatively short distance from one another, the struts 3 can be connected to the grating rings 2 with regard to the desired vibration behavior in the respectively required position and / or number.

With the device described, the ventilation grille 1 can be welded in a trough position in one operation, since the arcuate design of the ventilation grille 1 does not make it necessary to use a separate welding device and a separate welding process for each area of the ventilation grille. The ventilation grille can therefore be manufactured very easily and inexpensively.

Fig. 18 shows a conventional device for welding the ventilation grille according to the prior art. This ventilation grille 26 has a straight inner region 27 in axial section, which connects at an obtuse angle to a straight central region 28. A radially outer region 29 adjoins it at right angles. In order to produce such a ventilation grille, three work steps are required, which are shown in Figures a) to c) Fig. 18 are shown. A separate device 30 to 32 adapted to these grid areas is required for each of the three grid areas 27 to 29. This makes the production of this ventilation grille 26 very complex and lengthy.

The described curved shape of the ventilation grille 1 of the described embodiments, on the other hand, allows very simple and inexpensive production. Due to the curved cross-sectional design of the ventilation grille 1, it can be manufactured in one operation. It is only necessary to insert the grille rings 2 required for the ventilation grille 1 into the corresponding recesses 26 of the struts 24 and then to weld the required struts 3, 17 to the inserted grille rings 2.

Claims (12)

1. Engine mount for ventilators (11), having a ventilation grill (1) with radially running struts (3), which connect grill rings (2) lying coaxially relative to each other, and are fastened to an inner ring (5) with their radially inner end (4), and to an outer supporting ring (10) with their radially outer end (9), wherein, in order to adjust the engine mount to the oscillating behavior of the ventilator (11), the number and/or diameter of the struts (3) is varied with regard to acoustic noise reduction and/or self-resonances of the engine mount,
   characterized in that the inner ring is an inner supporting ring (5), which has a planar ring portion (6) that lies in a radial plane of the ventilation grill (1), and whose edge (7) is upwardly inclined and has fastened to it the radially inner ends (4) of the struts (3), and that an interface (8) is provided at the ring portion (6) of the inner supporting ring (5) in the form of openings distributed over the periphery for attachment to the ventilator (11).
2. Engine mount according to claim 1,
   characterized in that the number of struts (3) preferably consisting of metal is unequal to the number of blades (12) of the ventilator (11).
3. Engine mount according to claim 1 or 2,
   characterized in that the outer supporting ring (10) has a cylindrical exterior side, to which the radially outer ends (9) of the struts (3) are attached.
4. Engine mount according to one of claims 1 to 3,
   characterized in that the outer supporting ring (10) consists of a flat material, and is a strip bent into a cylinder.
5. Engine mount according to one of claims 1 to 3,
   characterized in that the outer supporting ring (10) consists of a flat material, which lies in a radial plane of the ventilation grill (1).
6. Engine mount according to one of claims 1 to 3,
   characterized in that the outer supporting ring (10) is comprised of at least one, preferably of several grill rings (2').
7. Engine mount according to one of claims 1 to 6,
   characterized in that the struts (3) are bent to form the radially outer ends (9) that preferably do not protrude over the outer supporting ring (10).
8. Engine mount according to one of claims 1 to 7,
   characterized in that the struts (3) preferably consisting of metal are curved in an arc-shaped convex manner over their length.
9. Engine mount according to one of claims 1 to 8,
   characterized in that some of the struts (17) protrude radially inward and/or outward beyond the grill rings (2), and that the protruding ends (20, 21) of the struts (17) are advantageously provided with connections (22, 23).
10. Engine mount according to one of claims 1 to 9,
    characterized in that some of the struts (3) have a length smaller than the radius of the ventilation grill (1), and in that preferably the short struts (3) have a smaller cross section than the longer struts (17).
11. Method for producing a ventilation grill (1) for the engine mount according to one of claims 1 to 10, in which grill rings (2) lying coaxially to each other and radially running struts (3, 17) are connected with each other, wherein the number of struts (3, 17) being varied with regard to acoustic noise reduction, characterized in that a welding device is used, which has an outer ring to which upright, radially extending struts (24) are connected, which have a curved end face (25) with depressions (26) spaced slightly apart one behind the other, that the struts (24) are arranged in such a way that the depressions (26) lie on a circle, that the grill rings (2) are placed in the depressions (26), and that the struts (3, 17) of the ventilation grill (1) to be produced are then fixedly welded to the grill rings (2).
12. Method according to claim 11,
    characterized in that the radially outer ends (9) of the struts (3) are fastened to an outer supporting ring (10).

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