EP2147217A1

EP2147217A1 - Fan cover and drive

Info

Publication number: EP2147217A1
Application number: EP08734970A
Authority: EP
Inventors: Petr Osipov; Karl-Heinz Tröndle; Michael Riffel
Original assignee: SEW Eurodrive GmbH and Co KG
Current assignee: SEW Eurodrive GmbH and Co KG
Priority date: 2007-04-13
Filing date: 2008-04-02
Publication date: 2010-01-27
Anticipated expiration: 2028-04-02
Also published as: BRPI0810901A2; DE102007017875A1; EP2147217B1; WO2008125220A1; CN101657645B; BRPI0810901B1; DE102007017875B4; CN101657645A

Abstract

The invention relates to a fan cover and a drive, wherein slits are located at the periphery of the fan cover for reducing the noise emission, wherein the slits are located such that they prevent the propagation of coupled vibration components.

Description

Fan cover and drive

Description:

The invention relates to a fan cover and a drive.

From US 5,118,252 a fan cowl is known, the reduced operating noise achievable by stiffening areas (see column 4, line 21 and claims 9 to 10 of this document). The production of the fan guard is very expensive, except as a plastic injection molded part.

From US 6 896 095 B2, a fan cowl is known in which flow noise is reduced by means of recesses.

From JP 072 985 A a rotating machine with stator and rotor and fan is known.

From JP 622 178 33 an electric motor is known which has a fan. In this case, a fan guard is provided, the resonance boxes, presumably Helmholtz resonators, comprises, for the absorption of vibrations of certain frequencies.

The invention is therefore based on the object to improve the safety and environmental protection, in particular, the emissions are to be reduced in industrial drives.

According to the invention, the object is achieved in the fan guard according to the claim 1, 2 or 3 and in the drive according to the features indicated in claim 14.

Important features of the invention are that slits for reducing the noise emission are arranged on the circumference of the fan cowling on the fan cowling.

BESTATIGUNGSKOPIE the slots being arranged in such a way that they hinder the propagation of coupled-in vibration components, in particular in the connection region of coupled-in vibration components.

Alternatively, the important features according to claim 2, that the fan cover

Includes connecting portions for attaching the fan cover to a structure-borne sound component, wherein slots are provided to reduce the airborne radiation introduced via the connection regions from the coupled regions.

In a further alternative, the important features according to claim 3, that the fan cover connecting areas for attachment of the fan cover to a structure-borne sound component comprises, wherein slots are provided as a sound brake for coupled via the connection areas structure-borne sound.

The fan cowling is provided by way of example for industrial drives, which usually include transmissions that are driven by electric motors, wherein the electric motors are supplied by converters. Pulse width modulated operation of the inverter and other electrical variables lead to time-varying forces on parts of the drive. For example, vibrations are excited by electromagnetically influenced parts. These vibrations cause the emission of sound as an emission into the environment. In particular, vibrations are also transmitted from the motor housing, including bearing flange, via screw connections to the fan hood of the motor screwed to the motor housing, where it is emitted as sound.

The advantage here is that with very cost-effective means the noise emissions are reducible and thus improves environmental protection. In addition, the mass of the arrangement, so the drive is reduced, and thus reduces the weight. In addition, material is saving and thus the environmental protection can be improved. It is therefore important in the invention that structure-borne noise is indeed coupled into the fan cover at the fastening points, but by means of the slots as a sound brake or structure-borne sound obstacle, the propagation of structure-borne noise into other areas of the fan cowl can be prevented or at least reduced. Thus, even sheet metal can be selected as a material for the fan cover and still the conversion of structure-borne noise in airborne noise can be reduced, which would be very pronounced without the slots. The slots are thus arranged in the area around the fastening means in such a way that they impede the propagation of structure-borne noise. It is It is also important that the structure-borne sound vibrates in different modes, that is to say forms of vibration in the radial, axial direction and the like. The invention teaches that the slots are mounted so that those modes that make up the majority of the coupled structure-borne sound are reduced or even suppressed by the shape and the shape of the slots.

Distinguishing from the sound forms mentioned here are the flow noise and the associated acoustic emission, which are caused by the rotating fan blade and the resulting air currents. The invention does not relate to these sound emissions. The aforementioned structure-borne noise coupled into the fan cowl is generated by the device to which the fan cowl is fastened. For example, this is a drive whose electric motor is powered by a converter. On the one hand, thus vibrations can be coupled by the inverter, on the other hand, vibrations by the alternating Bestrom ung the stator windings are coupled. In addition, vibrations also originate from the gearbox or from bearings and not fully balanced components. Also other causes are present. In this way, structure-borne noise is generated, which occurs on the housing part of the drive, in particular a bearing plate of the electric motor of the drive. By means of the attachment areas Einkoppelungsmöglichkeiten be created for this structure-borne noise in the fan guard. Since the fan cowl is designed around the engine essentially round or as a rounded polygon. Likewise, the motor is designed to be substantially round to the fan guard, with cooling fins and the like are not taken into account. Therefore, a substantial portion of the coupled structure-borne noise propagates in the circumferential direction and another important component also propagates in the axial direction. Accordingly, the slots are designed such that this propagation is reducible or even preventable.

Preferably, as a material for the fan cowl, a sheet metal, in particular steel sheet selectable. Thus, the slots are easily and quickly generated by punching. In addition, a high strength against mechanical loads can be achieved, in particular in contrast to the use of plastic.

In an advantageous embodiment would omit the slots, the essential portion of the coupled vibration components in the circumferential direction and / or propagate in the axial direction. The advantage here is that the slots are formed so that the spread of these essential components can be prevented or reduced. In an advantageous embodiment, the slots are oriented in the axial and / or circumferential direction. If the slots are oriented in the axial direction, it is advantageous to reduce the oscillation amplitudes of radial modes which would also propagate in the circumferential direction starting from the coupling-in areas. When oriented in the circumferential direction advantageously according to vibration amplitudes of other modes can be reduced. In particular, both types of slit can be combined.

In an advantageous embodiment, the slots arcuate, U-shaped and / or C-shaped surround the Einkoppelungsbereiche. In particular, the opening of the sheet, the U or C is oriented in the axial direction. The advantage here is that the propagation of appropriate modes in the fan guard can be suppressed or at least reduced.

In an advantageous embodiment, the coupling-in areas comprise connecting areas, in particular screwed connections, with the motor housing, in particular with a bearing plate of the motor housing. The advantage here is that conventional connection means can be used, via the structure-borne sound is coupled. So no sound-absorbing connection means, such as plastic washers and plastic screws must be used. When using such means, of course, even better reductions in the noise emissions can be achieved.

In an advantageous embodiment, the fan cowl comprises a cylindrical region in a first axial section, a bevelled region in a second axial region, and a fan cowl lattice in a third axial region. The advantage here is that more sound-reducing slots are providable. These are also inexpensive to produce.

In an advantageous embodiment, the slots extend in the axial direction only partially over the width of the cylindrical portion. The advantage here is that the stability of the fan guard is only slightly affected. In particular, extend from the edge or are provided only inside the fan guard.

In an advantageous embodiment, the connection areas, in particular screw connections, with the motor housing at the periphery of an angle of 360 ° a = each other. The advantage here is that in the invention any number n of attachment points on the circumference is providable.

In an advantageous embodiment, a respective slot arranged in the circumferential direction in front of the connection region has an angle β to the connection region, for

this holds true for 0 <ß ≤ -, in particular - <ß <-. Likewise, each one points in the circumferential direction

slit 1 arranged after the connection region has an angle γ to

Connection area, for which 0 <γ <-, in particular - ≤ γ ≤ -. Is an advantage

in this case, that a particularly good reduction of the airborne noise emission can be achieved, in particular for electric motors with a power of between 0.3 kW and 50OkW and at a rotational speed of between 0 and 5000 revolutions per minute.

In an advantageous embodiment applies to the axial extent of the slots t c • 0.5 ≤ t ≤ 5 ^■ c, where c is the distance from the center of the connecting portion to the edge of the hood of the fan shroud. The advantage here is that thus in the electric motors with a power between 0.3kw and 50OkW and at a speed between 0 and 5000 revolutions per minute a particularly good reduction of airborne noise emissions can be achieved.

In an advantageous embodiment, angle γ and angle ß is equal in magnitude. The advantage here is that a simple production is achievable and a particularly good reduction of airborne emissions can be achieved.

In an advantageous embodiment, the respective slots arranged in the circumferential direction after and in front of the connection region are arranged symmetrically with respect to the connection region. The advantage here is that

In an advantageous embodiment, the arrangement and formation of the slots are designed such that the sound emissions are reduced. The advantage here is that the molding no cost increases and thus a cost-effective method for reducing emissions is provided. In an advantageous embodiment, the slots are arranged on the circumference of the fan cover between mounting screws, in particular around them. The advantage here is that occurring there large vibration amplitudes of rotating waves and standing waves can be reduced.

In an advantageous embodiment, the fan cowl performs a housing-forming function for a fan and / or an angle sensor connected to the motor shaft. The advantage here is that the fan cover is a housing part that radiates low sound emission in a cost effective manner.

Important features of the invention in the drive are that it comprises at least one electric motor and / or a transmission, wherein slots are arranged on at least one housing part for reducing the noise emission. For example, the housing part is a cooling fin, a connection box or a fan cover. Particularly flat or thin flat parts, such as ribs and hoods contribute without the slots considerable amounts of sound emission.

The advantage here is that the drive by simple and inexpensive measures, such as slots of parts, sound-reducing executable. In any case, the structure-borne noise generated by the engine and / or transmission, which is coupled into the housing part at the respective attachment areas and / or connection areas for connection to the engine and / or transmission, in its propagation within the housing part preventable or at least is the spread erschwerbar. Thus, then occurs in the housing part only little structure-borne sound and it is then produced and radiated as a result, only little airborne sound. From this invention-related airborne sound that airborne sound is to be distinguished, which is generated by air currents on the fan blades and / or recesses of the fan cowl.

In an advantageous embodiment, a housing part is a cooling fin, a connection box or a fan cover. The advantage here is that the slots in different

Components are providable, not necessarily a sheet metal part but also a casting is used.

In an advantageous embodiment, connecting regions, in particular comprising fastening screws, which can be screwed into threaded bores of the motor housing are provided to connect the fan cover to the motor housing, in particular where structure-borne noise from the motor housing via the connecting portions in the fan cover. The advantage here is that, although structure-borne noise may be coupled in via the connection region, simple means, such as slots, are then used to reduce the propagation of structure-borne noise into the housing part. Thus, less airborne sound produced by the structure-borne sound can then also be emitted from this housing part, in particular the fan cowl.

In an advantageous embodiment, slots are arranged in areas of the fan guard with low rigidity or strength. The advantage here is that exactly in these areas without the slots large amplitudes would occur. The fact that the slots are made small, so short, then the strength is only slightly reduced, but reduces the vibration ability, in particular, the formation and spreading of circumferential and pulsating waves is prevented by the slots.

In an advantageous embodiment, slots are arranged in the second or third axial region of the fan cowl. The advantage here is that corresponding vibrations can be suppressed or at least reduced.

Further advantages emerge from the subclaims.

LIST OF REFERENCE NUMBERS

1 slot 5 2 recess for fixing screws

3 fan cover

4 fan cowl grille

5 cylindrical area

6 bevelled area 10 30 fixing screw

31 bearing flange

40 U-shaped or C-shaped slot

The invention will now be explained in more detail with reference to figures:

In the figure 1 is an inventive fan cover for the drive.

The fan cover 3 is connected by means of fastening screws, which are provided on the recesses 2, with the motor housing of the drive. There are four recesses 2 provided on the circumference.

The fan cover 3 has a fan cowl grille 4, which is provided for passing the cooling air flow of the fan, which of the fan cover 3 for protection and the

Influencing the cooling air flow is provided. In this case, the fan is mounted on an axial end portion of the engine, preferably a bearing flange. The cylindrical portion 5 is arranged axially oriented. The chamfered region 6 adjoins this region 5 and ends in the region of the fan hood grille 4.

At the periphery of the fan cover 3 eight slots 1 are provided, which are oriented in the axial direction. Preferably, two are provided each near the respective recess 2.

In further embodiments of the invention eight or a different number of recesses 2 are provided. The number of slots and the shape, in particular length, of the slots are adaptable and adaptable to reduce the noise emissions.

In other embodiments of the invention, other orientations of the slots 1 are advantageous, such as radial or oblique arrangement of the slots. The slots can therefore also be provided in the slanted area or even in the fan cowl lattice. It is particularly advantageous to mount the slots in areas where, without the slots, a large or even a locally maximum oscillation amplitude occurs.

The motor housing coupled via the mounting screws in the recesses 2 body sound. With axial orientation of the slots 1 next to the recesses 2, a propagation of the coupled structure-borne noise in the circumferential direction is prevented or at least reduced. It is, so to speak, the vibration wave propagation in the circumferential direction interrupted. Through the slots, the vibration amplitudes and Thus, the sound radiation, including noise development of the drive, greatly reduced. It is also important that there is a low tension in the material in the circumferential direction in those areas in which no fastening screws are provided between the slots. Thus, similar to an unstrung string of a stringed instrument, no or only little structure-borne noise can be converted into airborne sound and radiated. As a material for the fan cover 3 is thus also selectable metal, which provides better protection than plastic, but radiates a high proportion of structure-borne sound as airborne sound when tightened attachment. By means of the slots but the essential area is relaxed and thus reduces the radiation or even prevented.

Of course, other housing areas, such as motor housing, cooling fins of the motor housing, terminal box on the motor housing and the like, also emit sound. Again, attaching slots in areas of least rigidity is beneficial and reduces emissions.

If the structure-borne noise coupled in by the motor housing has a significant proportion of vibrations which are pronounced in the axial direction instead of as described above in the circumferential direction, it is preferably provided in the slot in the circumferential direction axially behind the fastening screw.

In Figure 4, a combination of two axial slots and a slot in the circumferential direction is shown, in which the slots are summarized as a U-shaped or C-shaped slot 40 within the sheet material of the fan guard. Thus, propagation and vibrations of structure-borne noise are reduced in the circumferential direction and completely prevented in the axial direction. Only about the two narrow webs in the circumferential direction is still transmitted some structure-borne noise. However, the narrow webs have the advantage that even when tightening the mounting screws no significant deformation of the axial region of the fan cover takes place, in which it is provided on the bearing plate and / or motor housing. Even if so cooling fins or other ripples are provided on the motor housing, a possible only small and small deformation is reached when tightening the mounting screws, so that the contact protection is maintained. In particular, no defined according to standard finger between the fan guard and bearing flange or motor housing into the interior of the engine is inserted. The security is thus increased. For this purpose, FIG. 3 b illustrates in an illustrative manner how the fan cowl 3 deforms when the fastening screws are screwed into the bearing plate 31 of the engine and no slots are present. In the case of large motors, the deformation can be so great that safety is jeopardized because a finger between the end shield and the fan cowl can be inserted into the interior of the engine, even though it was not insertable before tightening the screws. During operation of the motor, the effect of the vibration-induced movement of the fan cowling is additionally added.

In Figure 3a is shown that in the presence of the slots according to the invention, the fan cover 3 is not deformed or at least not visibly deformed but essentially remains in its cylindrical shape when the mounting screws are screwed into the bearing plate 31 of the engine.

In Figure 2 is still shown how an optimal dimensioning of the slots is provided for an industrial electric motor. In this case, the information refers to the axial slots 1 according to Figure 1, wherein each provided to the left of the mounting screw 30 slot 1 has an angle ß to the mounting screw and each provided right next to the mounting screw 30 slot 1 has an angle γ to the mounting screw. At n evenly arranged on the circumference

Mounting screws is the angle between these screws a =. n

Thus, is possible: 0 </? <-, O ≤ γ ≤ -. However, it has turned out that at:

- ≤ ß ≤ -, - ≤ γ ≤ - very good reduction of sound radiation is achievable. 20 5 20 5

In addition, the axial extent t of the slots is preferably such that 0.5 • c ≦ t ≦ 5 • c, where c is the distance from the screw axis to the hood edge of the fan cowl 3.

It is not necessary that the angle γ and the angle β are the same, but a symmetrical arrangement within the scope of the manufacturing tolerances is advantageous.

Corresponding to the U- or C-shaped slots of Figure 4, wherein the U or C substantially from the two axially aligned slots 1, for which said Relationships apply, and there is a connecting slot, which is exemplary oriented in the circumferential direction.

Preferably, the fan cover 3 can be connected by means of bayonet lock with the bearing flange or motor housing, for which purpose the fastening screws are screwed into the bearing flange or motor housing. For this purpose, the recesses for fastening screws are shaped accordingly. In this way, the fan cover is fast and easy connectable.

The sheet of fan cover is preferably selected as a steel sheet. Instead of four

Mounting screws on the circumference have also proved to be particularly advantageous. It is also important in the invention that the distortion caused by the mounting by means of the fastening screws of the fan cover is reduced by the slots, wherein the slots are mounted on both sides of the respective screw connections. The reduction of the strain then causes a reduction of the airborne sound radiation from the relaxed areas out.

In advantageous embodiments, the fan cowling is at least towards the engine, ie axial region in which the connection regions are arranged, substantially round or designed as a rounded polygon. Depending on the type of execution, although different high natural frequencies can be generated and thus different degrees of propagation effected, but the underlying principle of the invention is similar operating principle. In this case, the radial vibration components coupled in by the engine preferably extend in the circumferential direction starting from the connecting regions. Vibration components coupled in by the transmission also propagate in the axial direction starting from the connection regions. Accordingly, the slots are arranged as a sound barrier, in particular each oriented transversely to the propagation directions. Several slots can also be connected to each other.

Claims

claims:

1. Fan cover characterized in that

Slots for reducing the noise emission are arranged on the circumference of the fan cowling,

the slots being arranged in such a way that they hinder the propagation of coupled-in vibration components, in particular in the connection region of coupled-in vibration components.

2. Fan cover, comprising connecting portions for attaching the fan cover to a structure-borne sound component, wherein slots are provided to reduce the coupled via the connection areas from the structure-borne noise airborne radiation.

3. Fan cover, comprising connecting portions for fastening the fan cover to a structure-borne sound component, wherein slots are provided as a sound brake for coupled via the connection regions structure-borne sound.

4. Fan cover according to at least one of the preceding claims, characterized in that would omit the slots of the essential portion of the coupled vibration components in the circumferential direction and / or in the axial direction would spread.

5. Fan cover according to at least one of the preceding claims, characterized in that the slots are oriented in the axial and / or circumferential direction.

6. fan cowl according to at least one of the preceding claims, characterized in that the slots arcuate, U-shaped and / or C-shaped surround the coupling regions, 5 in particular wherein the opening of the arc, the U or C is oriented in the axial direction.

7. fan cowl according to at least one of the preceding claims, characterized in that

10, the coupling regions connecting areas, in particular screw, with the motor housing, in particular with a bearing plate of the motor housing include.

8. Fan cover according to at least one of the preceding claims, characterized in that

15, the fan cowl comprises a cylindrical region in a first axial section, a bevelled region in a second axial region, and a fan cowl grille in a third axial region.

9. fan cowl according to at least one of the preceding claims, 20 characterized in that the slots extend in the axial direction only partially over the width of the cylindrical portion, in particular extend from the edge or are provided only inside the fan cowl.

25 10. Fan cover according to at least one of the preceding claims, characterized in that on the periphery of the connecting areas, in particular screw, with the

Motor housing an angle, from «- ^ have to each other. n

11. fan cover according to at least one of the preceding claims, characterized in that a respectively arranged in the circumferential direction in front of the connecting portion slot 1 a

Has angle β to the connection region for which 0 ≤ β ≤ -, in particular

20 5

12. fan cowl according to at least one of the preceding claims, characterized in that a respectively arranged in the circumferential direction after the connection region slot 1 a

Has angle γ to the connection region for which 0 <γ ≦ -, in particular

a a

- <γ ≤ -

20 5

and or

for the axial extent t of the slots 0.5 • c ≦ t ≦ 5 • c holds, where c is the distance from the center of the connection region to the hood edge of the fan cover 3

and or

Angle γ and angle ß is equal in magnitude.

13. fan cowl according to at least one of the preceding claims, characterized in that the respectively arranged in the circumferential direction to and before the connection region slots are arranged symmetrically to the connection region

and or

Arrangement and formation of the slots are designed such that the noise emissions are reduced

and or

the slots are arranged on the circumference of the fan cowl between fastening screws, in particular around these

and or

the fan cowl performs a housing-forming function for a fan and / or an angle sensor connected to the motor shaft.

14. Drive, comprising at least one electric motor and / or a transmission, characterized in that

Slots are arranged on at least one housing part for reducing the sound emission caused by structure-borne noise emitted to the ambient air.

15. Drive according to at least one of the preceding claims, characterized in that a housing part is a cooling fin, a connection box or a fan cover

and / or connecting regions, in particular comprising fastening screws, which are screwed into threaded bores of the motor housing, are provided for connecting the fan cowl to the motor housing, in particular wherein structure-borne noise from the motor housing via the connecting regions in the fan cowl.