DE102017215261B4 - BLOWER FOR AN ELECTRICAL DEVICE - Google Patents

Abstract

Fan (1) with an electric motor (2) and an impeller (14, 15, 16) attached to the shaft (13) of the electric motor (2) for conveying air from an impeller inlet (17) to at least one impeller outlet (18) , with a fan hood (30) for deflecting air, wherein at least one rib (19) is present which protrudes from the inside of the fan hood (30) and which is arranged opposite the impeller outlet (18), characterized in that the at least a rib (19) runs along a portion of a helix.

Description

Field of invention

The present invention relates to a fan for an electrical appliance, in particular for a vacuum cleaner. A blower in the sense of the present invention is a machine that conveys air by means of an impeller rotating in a housing. There is a suction side and a pressure side. With a fan in the sense of the present invention, in a preferred embodiment of the invention, a pressure ratio between 1.3 and 3 can be achieved between the suction side and the pressure side.

State of the art

From the prior art, for example, the generic DE 10 2014 208 128 A1 , DE 297 17 906 U1 , EP 0 602 007 A2 , DE 10 2016 109 018 A1 such as DE 10 2012 211 252 A1 known. These disclose blowers for electrical appliances having an electric motor and an impeller attached to the shaft of the electric motor. Air is sucked in through the impeller. Such an impeller usually comprises a front and a rear cover plate. There is a space between the two cover plates in which wings are mounted. Adjacent wings form air channels. The front cover plate has an impeller inlet in the middle of the impeller. Impeller outlets for air are provided along the periphery of the impeller, i.e. along the outer edge of the impeller. If the impeller rotates as intended, air flows into the impeller inlet, from here on through the air ducts, namely radially outwards to the impeller outlets. Then the air is directed from the impeller outlets in the direction of the electric motor with the help of a blower hood.

The prior art also includes the generic one EP 0 602 007 A2 known, which also discloses a fan for an electrical appliance. Air emerges from the side of an impeller arranged inside a fan cover. The air exiting from the side flows to a diffuser which comprises a large number of blades. After exiting the diffuser, air is deflected by 90 ° in the direction of the electric motor.

The pamphlet KR 10 2016 0 019 140 A discloses a fan having spiral ribs protruding from an inside of an associated fan shroud.

The problem underlying the invention

It is the object of the invention to create a fan with low noise development. In particular, this should be possible without having to provide additional installation space. A low manufacturing cost should preferably also be possible. Retrofitting of existing blowers should preferably also be easily possible.

Solution according to the invention

The reference signs in all claims do not have a restrictive effect, but are only intended to improve their readability.

The problem posed is achieved by a blower with the features of claim 1. Advantageous refinements result from the dependent claims. A secondary claim relates to a fan cover for retrofitting existing fans.

The fan according to the invention comprises an electric motor and an impeller attached to the shaft of the electric motor for conveying air from an impeller inlet to at least one impeller outlet. The at least one impeller outlet is generally located on the periphery of the impeller. The fan includes a fan shroud.

The fan according to the invention is made possible by at least one rib which protrudes from the inside of the fan cover and which is arranged opposite the impeller outlet. The at least one rib is therefore basically located between the periphery of the impeller and a lateral wall area of the fan cover. Since the at least one rib is provided on the inside of the fan cover, it consequently protrudes inward.

The impeller in the sense of the present invention is a component which rotates during operation and thereby causes the air flow aimed at by the fan. Air usually emerges from the side of the impeller via one or more impeller outlets. The direction of flow of the air is then basically perpendicular or at least substantially perpendicular to the shaft of the electric motor. In particular, the impeller is designed as described in the introduction to the description.

The fan cover is used to deflect air, basically in the direction of the electric motor. Such a fan cover for deflecting air is a component which, during operation, deflects this air flowing in the direction of the fan cover, in particular by 90 ° or at least essentially by 90 °. The direction of flow of the air is changed by the fan hood. Following the deflection, air basically flows at least essentially parallel to the shaft of the electric motor or has at least one flow component parallel to the shaft of the electric motor. After being deflected by the fan cover, the air can therefore also flow helically around the shaft of the electric motor, for example, and therefore then has a flow component parallel to the shaft of the electric motor.

With the exception of an opening for air to enter, the fan hood is shaped like a hood and, in an operationally ready state, is air-impermeable or at least substantially air-impermeable. The opening provided for the entry of air is arranged such that air can flow through the opening in the direction of the impeller inlet. The blower hood basically has an upper wall area and a laterally circumferential wall area adjoining it on the outside. The upper wall area can be designed in the shape of a lid. This can be flat, arched or conical. The side wall area can be cylindrical. The lateral wall area can, however, also be a polygon in cross section, for example square. The lateral wall area can have wall sections which are arranged around the impeller and whose cross sections run in a straight line. In cross-section, the side wall area is then not circular as in the case of a cylinder shape. Instead, the cross section can then, for example, be pentagonal, hexagonal, heptagonal or octagonal and thus only approximate a cylindrical shape.

The upper wall area of the fan cover includes the opening provided for the entry of air. The impeller is surrounded by the side wall area. The impeller is therefore located within the side wall area of the fan cover. The two mentioned wall areas of the fan cover divert air emerging from the impeller during operation, basically in the direction of the electric motor.

A rib for deflecting air in the direction of the electric motor in the sense of the present invention is a flat component. This protrudes from the inside of the fan cover. This means that it extends from the inside of the fan cover in the direction of the interior of the fan cover. Each rib basically extends over a relatively short section of a wall area of the fan cover. Each rib is arranged on the fan hood and thus in the area of the air deflection and therefore influences the flow of air during this air deflection.

In contrast to the state of the art mentioned at the beginning, air is not only diverted to the electric motor with the aid of a fan cover. Instead, the flow of air is additionally influenced by the one or more ribs during the deflection, which leads to a reduction in noise. It has been found that in this way noise can be avoided in particular that occur in the partial load range at low frequencies, especially in the frequency range from approx. 1500 Hz to approx. 3000 Hz. Noise can thus be reduced or device insulation can be used which would otherwise be necessary in order to be able to achieve a comparably low noise level. In the last-mentioned case in particular, the production effort can be reduced considerably and consequently costs can be saved that would otherwise have to be expended for device insulation in order to achieve noise insulation. No additional installation space has to be provided to accommodate the ribs. The solution according to the invention can be provided with little manufacturing effort.

In an advantageous embodiment, the at least one rib is held by the fan cover, that is to say is attached, that is to say fastened, directly or indirectly to the fan cover. The at least one rib then adjoins a lateral wall area of the fan hood in a particularly tight, preferably airtight manner. This results in a further improved noise reduction. At the same time, the at least one rib is held in a structurally simple manner.

In order to be able to deflect air in the direction of the electric motor in a manner that is further improved for noise reduction, the at least one rib protrudes perpendicularly or at least substantially perpendicularly from a lateral wall area of the fan hood and / or extends perpendicularly or at least substantially perpendicularly to Electric motor shaft. This results in a particularly suitable low noise level.

In order to be able to deflect air in the direction of the electric motor in a manner particularly suitable for noise reduction, the one or more ribs run in the manner of a section of a helix. The one or more ribs then run like the section of a helix in particular when the lateral wall area of the fan hood is cylindrical in cross section. The one or more ribs can also run in a straight line, for example. This is particularly the case when the side wall area of the fan hood is a polygon in cross section and the wall sections between two corners run in a straight line in cross section.

The one or more ribs close with a plane that runs perpendicular to the shaft of the electric motor, preferably an angle between 0 ° and 90 °, particularly preferably between 5 ° and 80 °, a. The ribs therefore preferably run at an angle to the plane mentioned in order to reduce noise with little technical effort, without having to increase the installation space of such a fan. It is also possible for each rib to run parallel to the shaft of the electric motor and consequently to form a right angle with the plane. However, a sloping course is preferable. In order to be able to deflect air in the direction of the electric motor in a manner particularly suitable for noise reduction, the angle between a plane that forms a right angle with the shaft of the electric motor and a rib is less than 45 °, particularly preferably less than 30 ° and / or preferably greater than 10 °, preferably greater than 20 °. The angle is preferably 20 ° or 25 °.

In order to be able to deflect air in the direction of the electric motor in a way that is particularly suitable for noise reduction, the number of ribs is greater than or equal to the number of subsequent openings of a diffuser through which air reaches the electric motor. These openings basically have a direction of extent parallel or at least substantially parallel to the shaft of the electric motor.

In order to be able to deflect air in the direction of the electric motor in a manner particularly suitable for noise reduction, the at least one rib preferably adjoins a base of the diffuser, which preferably leads in the form of a ramp to an aforementioned opening of the diffuser, through which Air reaches the electric motor.

In order to be able to deflect air in the direction of the electric motor in a manner particularly suitable for noise reduction, the direction of extension of the blades of the impeller in the area of the periphery of the impeller basically forms an acute angle with the side wall area of the fan. Following the direction of extension of the blades, the one or more ribs run in the manner of a helix towards the upper or lower wall area of the fan cover. In the case of a plurality of ribs, these are basically evenly distributed around the impeller without ribs then overlapping, for example in sections. The ribs are basically arranged one behind the other.

In order to be able to deflect air in the direction of the electric motor in a manner particularly suitable for noise reduction and at the same time structurally simple, the one or more ribs are made of plastic, preferably made of a thermoplastic plastic.

In order to be able to deflect air in the direction of the electric motor in a manner that is particularly suitable for noise reduction and at the same time structurally simple, there are a plurality of ribs which are part of a one-piece component which comprises an annular region. This component is therefore also called an annular component. The ring-shaped component including its ribs is thus produced in one work step, in particular by an injection molding process. In this embodiment in particular, the ends of the ribs are preferably connected to one another in order to avoid vibrations and to improve stability.

In order to be able to deflect air in the direction of the electric motor in a manner that is particularly suitable for noise reduction and at the same time structurally simple, the outer diameter of the annular component corresponds to the inner diameter of the side wall area of the fan hood, thus creating a tight connection between the fan hood in a structurally simple manner and to be able to provide the ribs. This also improves the stability and avoids disadvantageous vibrations of the ribs during operation.

Air is deflected by the hood and the one or more ribs, in particular by approximately 90 °. A deflection by approximately 90 ° within the meaning of the present invention is at least present when at least one component of the air flow has been deflected by approximately 90 °. As a result of this approximately 90 ° deflection, the component of the air flow runs in particular parallel to the shaft of the electric motor. Overall, the air flow can therefore also run obliquely to the shaft of the electric motor. In this embodiment, it is only essential that the flow of air can be broken down into components, i.e. flow directions, in such a way that after the deflection one component runs parallel to the shaft of the electric motor, i.e. air flows from the fan cover along the shaft of the electric motor.

In order to be able to reliably connect the ring-shaped component to the fan hood in a particularly simple manner, the ring-shaped component has upwardly projecting one or more webs which are passed through bores provided in the upper wall area of the fan hood. After passing through, the upwardly protruding webs are preferably flattened in order to connect the ring-shaped component to the fan hood in a form-fitting manner. As a result of the flattening, the webs outside the fan cover have been widened. The widened area of the webs is always close to the fan cover. A reliable and permanent form-fitting connection between the annular component and the fan cover is created in a suitable manner. The Flattening is possible with low pressure and thus in a particularly simple manner by supplying heat if the annular component is made of a thermoplastic material. As an alternative or in addition, the annular component comprising one or more ribs can be glued to the fan hood and / or pressed into the fan hood.

In order to be able to deflect air in the direction of the electric motor in a manner particularly suitable for noise reduction, there are several ribs, preferably at least six ribs, particularly preferably at least eight ribs. The ribs are evenly distributed in a ring around the periphery of the impeller. Basically, the ribs do not overlap. In particular, the ribs have the same dimensions and are arranged at the same height around the impeller.

In a technically simple embodiment, the one or more ribs are attached to the fan hood by riveted connections.

In one embodiment of the invention, for reasons of stability, the fan hood is preferably made of metal, for example aluminum or an iron alloy. For reasons of stability, the ribs can also consist of metal in order to avoid vibrations of the ribs.

In one embodiment, after the air deflection caused by the fan hood, the air is passed on via one or more further ribs in the direction of the electric motor. The one or more further ribs preferably form the bottom of the depressions. These ribs run, in particular, in a manner comparable to the ribs protruding from the fan cover, that is to say in particular also like the section of a helix and / or at an angle to a plane which forms a right angle with the shaft of the electric motor. These further ribs are then inclined in the same way and in the same direction as the ribs protruding from the fan cover. These ribs preferably widen in the direction of the electric motor. Each rib of the fan cover preferably adjoins one end to one end of a rib which forms a base of a depression. The properties of the blower can be further improved by these configurations. The ribs, which form a base of a recess, are part of the diffuser.

• - die einzelnen Rippen erstrecken sich überwiegend quer (oder senkrecht) zu der Welle des Elektromotors, um Geräusche zu reduzieren;
• - der Winkel zwischen einer Ebene quer zur Welle des Elektromotors und einer einzelnen schrägen Rippe ist kleiner als 45°, besonders vorzugsweise 30°, besonders vorzugsweise 25°, besonders vorzugsweise 20°, um so abknickende Luftströmungen und damit einhergehende Leistungsverluste zu vermeiden;
• - eine einzelne Rippe stellt einen Teil einer archimedischen Schraube dar oder ist konkav oder konvex gekrümmt (von der Motorachse in Richtung der Gebläsehaube gesehen), um Leistungsverluste zu vermeiden;
• - der Spaltabstand zwischen Außenradius von dem Laufrad zu den einzelnen schrägen Rippen der Gebläsehaube beträgt nicht mehr als 1 mm, vorzugsweise 0,5 mm, um so zwischen der Außenseite von einem nachfolgenden Leitapparat und den Rippen nachteilhafte Querströmungen zu vermeiden; dieser Spalt ist grundsätzlich frei von weiteren Bauteilen;
• - die Höhenerstreckung der Rippen entspricht mindestens der Höhe der Austrittsöffnung bzw. Auslässe an dem Laufrad, um alle Teilströme der Ausblasluft aus dem Laufrad auf dem ganzen Umfang den Rippen zuführen zu können;
• - die Anzahl der Austrittsöffnungen bzw. Auslässe von dem Laufrad zu der Anzahl der einzelnen Rippen ist frei wählbar, ohne Nachteile befürchten zu müssen;
• - das Verhältnis von den einzelnen Rippen zu den Öffnungen von einem nachfolgenden Leitapparat ist paritätisch, um zu einem besonders leistungsfähigen und geräuscharmen Gebläse zu gelangen;
• - das Luftaustrittsende von einzelnen Rippen geht in einen Eingang von dem Leitapparat über, um störende Treppenabsätze in einem Übergangsbereich und damit einhergehende Strömungsverluste zu vermeiden;
• - die Anzahl der Rippen liegt zwischen 8 und 10, um bereits vorhandene, handelsübliche Gebläse mit solchen Rippen einfach und kostengünstig nachrüsten zu können;
• - die einzelnen Rippen sind mit den benachbarten Rippen an deren Oberseite (zum Lufteintritt hin) miteinander verbunden, um die Stabilität zu verbessern;
• - die einzelnen Rippen sind mit den benachbarten Rippen an deren Unterseite (zum Luftaustritt hin) miteinander verbunden, um die Stabilität zu verbessern und Schwingungen der Rippen zu vermeiden;
• - die seitliche Innenwand der Gebläsehaube ist parallel zu der Welle des Elektromotors angeordnet, um Luft besonders geeignet weiterleiten zu können;
• - die Rippen sind Teil eines einstückigen Bauteils, welches über z: B. vier Zapfen mittels Stemmverbindung an der Gebläsehaube befestigt sind, um so eine einfache und preiswerte Befestigungsmöglichkeit mit der Gebläsehaube zu schaffen; alternative Befestigungsmöglichkeiten sind Einpressen oder Verkleben mit der Gebläsehaube.

The following configurations are of particular advantage:

• the individual ribs extend predominantly transversely (or perpendicularly) to the shaft of the electric motor in order to reduce noise;
• - The angle between a plane transverse to the shaft of the electric motor and a single inclined rib is less than 45 °, particularly preferably 30 °, particularly preferably 25 °, particularly preferably 20 °, so as to avoid kinking air flows and the associated power losses;
• - a single rib forms part of an Archimedean screw or is concave or convex curved (viewed from the motor axis in the direction of the fan cover) in order to avoid power losses;
• the gap distance between the outer radius of the impeller and the individual inclined ribs of the fan cover is not more than 1 mm, preferably 0.5 mm, in order to avoid disadvantageous cross flows between the outside of a downstream diffuser and the ribs; this gap is basically free of other components;
• - The height extension of the ribs corresponds at least to the height of the outlet opening or outlets on the impeller in order to be able to feed all partial flows of the blown air from the impeller over the entire circumference of the ribs;
• The number of outlet openings or outlets from the impeller to the number of individual ribs can be freely selected without having to fear disadvantages;
• - The ratio of the individual ribs to the openings of a subsequent diffuser is equal in order to achieve a particularly powerful and low-noise fan;
• - The air outlet end of individual ribs merges into an entrance of the diffuser in order to avoid disruptive landings in a transition area and the associated flow losses;
• - The number of ribs is between 8 and 10, in order to be able to retrofit existing, commercially available fans with such ribs easily and inexpensively;
• the individual ribs are connected to one another with the adjacent ribs on their upper side (towards the air inlet) in order to improve stability;
• the individual ribs are connected to one another with the adjacent ribs on their underside (towards the air outlet) in order to improve the stability and avoid vibrations of the ribs;
• - the lateral inner wall of the fan hood is arranged parallel to the shaft of the electric motor in order to be able to pass on air in a particularly suitable manner;
• The ribs are part of a one-piece component which is fastened to the fan hood by means of a caulking connection via, for example, four pegs, in order to create a simple and inexpensive means of fastening to the fan hood; alternative fastening options are press-fitting or gluing to the fan cover.

The invention also relates to a fan cover for a fan according to the claims with an upper wall area which has a preferably centrally arranged opening for an inlet of air and a side wall area connected to it with ribs attached to the inside of the side wall area, which run along the ring-like, side wall area are evenly distributed and each run like a section of a helix. This cap makes it possible to retrofit existing blowers in a technically very simple manner by simply replacing this blower hood with the existing blower hood. This allows noise reduction measures to be taken retrospectively in the case of existing fans. Any further structural change is not required.

This fan cover is preferably designed as described in the present application. In particular, the ribs are fastened on the inside by riveted connections or there is a one-piece, preferably made of plastic, annular component with the ribs attached to it, which is connected to the fan cover.

The fan according to the invention is installed in particular in a vacuum cleaner.

The present invention enables the creation of a blower with low noise generation with simple structural and inexpensive means. These properties can be further improved by the preferred embodiments.

Figure list

Further advantageous configurations are described in more detail below with reference to the exemplary embodiments shown in the drawings, to which the invention is not limited, however.

• 1: perspektivische Ansicht von einem Gebläse
• 2: Längsschnitt durch ein Gebläse
• 3: wie 2, jedoch ohne Laufrad und Motor;
• 4: Gebläsehaube mit Rippen
• 5: wie 4 in Explosionsdarstellung;
• 6: alternative Ausführungsform einer Gebläsehaube mit Rippen; einzelne Segmente bilden die Rippen, die über Nietverbindungen befestigt sind;
• 7: wie 6 in Explosionsdarstellung.

They show schematically:

• 1 : perspective view of a fan
• 2 : Longitudinal section through a fan
• 3 : as 2 but without impeller and motor;
• 4th : Fan hood with ribs
• 5 : as 4th in exploded view;
• 6th : alternative embodiment of a fan cover with ribs; individual segments form the ribs, which are attached via riveted connections;
• 7th : as 6th in exploded view.

The 1 shows a fan 1 with an electric motor 2 . An existing plastic component of a diffuser has an upper annular portion 3 and four downwardly protruding webs 4th on. This component is also referred to below as an annular component with protruding webs. The bridges 4th are using screws with the electric motor 2 connected. A metal fan cover 30th (please refer 5 and 7th ) comprises a lateral, cylinder-like wall area 5 and an upper, cover-shaped wall area 6th . The upper wall area 6th includes an opening 7th for air to enter. A lower section 8th of the side wall area 5 surrounds the upper annular section 3 of the component made of plastic and lies tightly, in particular with a friction fit, on this annular section 3 at. The lower section 8th with the annular section 3 for example be glued. The component made of plastic with the annular section 3 thus connects the fan cover 30th with the electric motor 2 .

The metal fan cover 30th is with a rubber sleeve 9 connected. The rubber cuff 9 allows the blower 1 suitable to be tightly connected to an opening within a device through which air is to be drawn in. In particular, the device is a vacuum cleaner.

Another component made of plastic with an annular area with ribs attached thereto has webs protruding upward from the annular area 10 on that through the top wall area 6th the fan hood are passed through. These webs 10 are flattened on the top, around the annular component with attached ribs with the fan cover 30th to connect positively.

At the bottom is the electric motor 2 through a metal cap 11 covered. The cap 11 has four bars 12th on that also with the already mentioned screws with the electric motor 2 are connected.

Through the bridges 4th , 12th is achieved that air from inner areas of the electric motor 2 out and into the inner areas of the electric motor 2 can flow in almost unhindered, so the electric motor 2 to cool. Still, the electric motor is 2 suitably protected from external influences.

In the 2 a longitudinal section through the 1 illustrated blower 1 shown. Here is the wave 13 of the electric motor 2 to see that with an impeller 14th , 15th , 16 connected is.

The impeller comprises a metal cover plate on the front 14th and a rear cover plate made of metal 15th . There is a space between the two cover plates 14th and 15th , in the wing made of metal 16 are mounted. The wings are above rivets 16 with the two cover plates 14th and 15th connected. Adjacent wings 16 form air channels. The front cover plate 14th has an impeller inlet in the middle 17th on. Impeller outlets 18th for air are along the periphery of the impeller 14th , 15th , 16 , i.e. along the outer edge of the impeller 14th , 15th , 16 , available. Rotates the impeller 14th , 15th , 16 , as intended, air flows into the impeller inlet 17th in, from here further through the air ducts, namely radially outwards to the impeller outlets 18th . Then the air is blown with the help of the fan cover 30th towards the electric motor 2 diverted.

Adjacent to the periphery of the impeller 14th , 15th , 16 , i.e. adjacent to the impeller outlets 18th , are ribs 19th available. The number of ribs 19th is equal to the number of openings listed below 23 of the diffuser. Ribs 19th are part of a one-piece plastic component that has an annular area 20th includes. Ribs 19th stand from the annular area 20th essentially perpendicular. From the wall area 5 seen from the ribs extend 19th towards the wave 13 . This direction of extent closes with the shaft 13 a right angle.

One every rib 19th runs according to a section of a helix, that is to say curved, from the bottom to the top obliquely and along the inner wall of the annular region 20th . With that the ribs run 19th in relation to a wave 13 vertical plane inclined like a ramp. The angle between the ribs 19th and this plane is 25 °. The outside diameter of the annular area 20th corresponds to the adjoining inner diameter of the fan cover 30th so that the annular area 20th close to the corresponding wall area of the fan hood 30th is applied. Ribs 19th together with the fan cover 30th that from the air wheel outlets 18th escaping air by approx. 90 ° towards the electric motor 2 is diverted. Ribs 19th are arranged in the area of this air deflection. Ribs 19th are dimensioned and designed the same and run in the same way.

In the 2 is a cylindrical collar 21st the fan cover 30th to see the inside of the rubber cuff 9 reaches in, around the cuff 9 on the fan cover 30th to fix.

The one through the fan cover 30th After the deflection, deflected air flows into depressions 22nd of the annular component 3 with the protruding bars 4th , i.e. the diffuser, into it. The indentations are up towards the fan cover 30th open and also have an opening on each side 23 through which air can flow towards the electric motor. The reason 24 of the wells 22nd runs like the ribs 19th as a section of a helix.

This ground is formed by a rib 24 as well as the deepening 22nd widen to the bottom in supervision 24 seen towards the opening 23 . The ring-shaped component 3 with the openings 23 is preferably made in one piece and is called a diffuser.

The ring-shaped component 3 with the protruding bars 4th , the diffuser, has two web-shaped brackets 25th for brushes of the electric motor 2 on.

According to the invention, therefore, in the area between the impeller outlet 18th and subsequent openings 23 through which the air passes during operation, curved ribs 19th introduced, which in the axial and or radial direction to the openings 23 of the diffuser are bent. Where is the number of these ribs 19th greater than or equal to the number of openings 23 , through which the air subsequently flows towards the electric motor 2 is forwarded. Is the number of ribs 19th equal to the number of openings 23 , so is the starting point of a rib 19th at the nearest edge 4th from which a reason 24 to an opening 23 leads. The variant, number of ribs 19th is equal to the number of openings 23 , represents a particularly advantageous embodiment.

The distance between the impeller outlet 18th and rib 19th should be chosen as low as possible. The limit lies in the component and manufacturing tolerances.

The 3 and 4th illustrate the structure of the fan cover 30th in connection with a component made in one piece from plastic, which has an annular area 20th as well as eight ribs 19th includes. This component is therefore also an annular component 20th with ribs 19th called. The ring-shaped component is thus created in one work step 20th including his ribs 19th produced, in particular by an injection molding process.

The outer diameter of the annular component 20th with the bars 19th corresponds to the inner diameter of the side wall area 5 the fan cover 30th in order to create a tight connection between the fan cover in a structurally simple manner 30th and to be able to provide the ribs 19. This is done in the 4th shown. Ribs 19th are arranged one behind the other around the impeller and do not overlap when viewed from above on the fan cover.

From a manufacturing point of view, it is advantageous to have gaps 26th to be provided in the lateral edge area, which is attached to the ribs 19th adjoin and preferably as in the 5 shown are triangular. The 5 illustrates that the area 8th the fan hood opposite the remaining side wall area of the fan hood 30th is preferably offset to the outside in order to be able to connect the fan cover particularly reliably and suitably to the other fan components.

The individual ribs 19th are in this embodiment with the adjacent ribs 19th connected to one another at the top (towards the air inlet) to improve stability. Also are the individual ribs 19th with the adjacent ribs 19th connected to each other on the underside (towards the air outlet) in order to improve stability and avoid vibrations of ribs.

The 5 and 6th show another embodiment in which ribs made of metal 19th via riveted connections 27 with the fan cover 30th are connected. These ribs 19th overlap when viewed from above on the fan cover. Like in the 7th can be seen, the side wall area 5 the fan cover slots 28 on. Through these slots 28 become protrusions 29 of the ribs 19th inserted through to rivet the ribs 19th with the inside of the side wall area 5 connect to.

Both in the case of the 4th and 5 as well as in the case of the 6th and 7th the ribs run like a section of a spiral. Both the ribs 19th as well as the reason 24 close with a perpendicular to the shaft 13 of the electric motor 2 extending plane an angle between 20 ° and 25 °.

The invention provides a low-noise fan without having to operate an excessively high technical manufacturing effort or have to provide a large installation space. Tests and comparative tests have shown that a significant reduction in noise is achieved, especially in the frequency range between approx. 1500 Hz and approx. 3000 Hz when the fan is operating at part load.

The features disclosed in the above description, the claims and the drawings can be important both individually and in any combination for the implementation of the invention in its various configurations.

List of reference symbols

1:

fan

2:

Electric motor

3:

annular section of a component with webs

4:

web

5:

lateral wall area of a fan cover

6:

upper wall area of the fan cover

7:

Opening in the upper wall area of the fan hood

8th:

lower section of the side wall area of the fan cover

9:

Rubber sleeve

10:

Bridges

11:

cap

12:

Bridges

13:

Electric motor shaft

14:

front cover plate of the impeller

15:

rear cover plate of the impeller

16:

Impeller - blades

17:

Impeller inlet

18:

Impeller outlet

19:

rib

20:

annular area of a component with ribs

21:

cylindrical collar of the fan cover

22:

deepening

23:

lateral opening of the recess

24:

Reason for deepening

25:

bar-shaped bracket

26:

gap

27:

Riveted connection

28:

slot

29:

head Start

30:

Fan cover

Claims (14)

Fan (1) with an electric motor (2) and an impeller (14, 15, 16) attached to the shaft (13) of the electric motor (2) for conveying air from an impeller inlet (17) to at least one impeller outlet (18) , with a fan hood (30) for deflecting air, wherein at least one rib (19) is present which protrudes from the inside of the fan hood (30) and which is arranged opposite the impeller outlet (18), characterized in that the at least a rib (19) runs along a portion of a helix. Fan (1) Claim 1 , characterized in that the at least one rib (19) is held by the fan cover (30). Blower (1) according to one of the preceding claims, characterized in that the at least one rib (19) protrudes vertically or at least substantially vertically from a lateral wall area (5) of the blower hood (30) and / or extends vertically or at least substantially vertically extends to the shaft (13) of the electric motor (2). Blower (1) according to one of the preceding claims, characterized in that the angle between a plane which forms a right angle with the shaft (13) of the electric motor (2) and the at least one rib (19) is less than 45 °, particularly preferably smaller than 30 °, and preferably larger than 10 °, preferably larger than 20 °, preferably 20 ° or 25 °. Blower (1) according to one of the preceding claims, characterized in that the number of ribs (19) is greater than or equal to the number of subsequent openings (23) of a diffuser through which air reaches the electric motor (2). Blower (1) according to one of the preceding claims, characterized in that the at least one rib (19) adjoins a base (24) which preferably leads in the form of a ramp to an opening (23) of a diffuser through which air to Electric motor (2) arrives. Blower (1) according to one of the preceding claims, characterized in that the at least one rib (19) is part of a one-piece component with an annular region (20), the one-piece component being connected to the fan cover (30). Fan (1) Claim 7 , characterized in that the outer diameter of the annular region (20) corresponds to the inner diameter of the side wall region (5) adjoining it. Fan (1) after one of the Claims 7 or 8th , characterized in that the component with the annular region (20) has one or more webs (10) protruding upward, which are passed through a wall region of the fan hood (30). Fan (1) Claim 9 , characterized in that the webs (10) are widened outside the fan cover (30). Fan (1) after one of the Claims 7 to 10 , characterized in that the component with the annular region (20) consists of a thermoplastic material. Fan (1) according to one of the preceding claims, characterized in that there are several ribs (19), preferably at least six ribs (19), particularly preferably at least eight ribs (19), which are annular around the periphery of the impeller (14, 15, 16) are evenly distributed and run in the same way. Blower (1) according to one of the preceding claims, characterized in that there are several ribs (19) which are equally dimensioned and designed. Blower hood for a blower (1) according to one of the preceding claims, with an upper wall area (6) which has a centrally arranged opening (7) for an inlet of air and a lateral wall area (5) connected to it and on the inside of the lateral wall area (5) attached ribs (19) which are evenly distributed along the lateral wall area (5) and which run like a section of a helix.

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