DE102014204608A1 - vacuum cleaner fan - Google Patents

Abstract

A vacuum cleaner fan comprises a housing, an electric motor with a motor shaft (2) and a fan wheel (1), which is arranged on the motor shaft (2), wherein the motor shaft (2) with two axially spaced ball bearings is rotatably mounted relative to the housing, wherein an inner ring (6) of a first ball bearing (4) fixed to the motor shaft (2) is connected, and wherein an outer ring (7) of the first ball bearing (4) in the axial direction via an elastic damping element (23) against a bearing surface ( 18) of a bearing seat (17) and is arranged in the radial direction without contact with the bearing seat (17). As a result, an improvement in the durability of the storage and / or in terms of vibration transmission to the housing can be achieved.

Description

Field of the invention

The invention relates to a vacuum cleaner fan, which comprises a housing, an electric motor with a motor shaft and a fan wheel, which is arranged on the motor shaft, wherein the motor shaft with two axially spaced ball bearings is rotatably mounted relative to the housing and wherein an inner ring of a first ball bearing fixed connected to the motor shaft.

Background of the invention

In a known vacuum cleaner fan motor shaft is mounted in two axially spaced ball bearings, wherein the two bearings are employed in O arrangement. Both bearings are firmly fixed in their respective bearing seat with the help of a bond. The achieved by the employment bias is additionally increased during operation by the negative pressure generated by the fan, which pulls on the motor shaft. As a result, a backlash and high rigidity can be achieved, since both bearings carry axially.

An important feature of vacuum cleaners is the noise generated during operation, which, among other things, contributes to the structure-borne sound produced by the vacuum cleaner on the blower and transmitted to the housing of the vacuum cleaner via the mechanical coupling of the blower. To reduce structure-borne noise, it is known to store the motor shaft with play.

In the patent US 4,969,797 It is proposed that the shaft of a fan of a fan is mounted at its two ends in each case with a bearing, wherein the shaft has spirally arranged grooves which suck air through holes in the bearing, so that in the radial direction an air bearing is effected. The front end of the shaft is formed with a spherical surface and is in point contact with the center of an end surface of the bearing.

According to WO 2005/029680 A1 For example, a rotor assembly of a motor includes a rotor disposed on a shaft, the shaft each having a bearing at both ends thereof. The bearings are mounted with O-rings in a stator assembly, with the O-rings located on the outside of the bearing or a bearing housing rigidly connected to the bearing. This allows the rotor assembly to rotate above its center of mass above a critical speed.

However, the known bearing assemblies are not optimal when used in a vacuum cleaner fan, in particular with regard to the rigidity and durability of the bearing as well as with respect to the vibration transmission to the housing and the structure-borne sound caused thereby.

The problem underlying the invention

It is an object of the invention to provide a generic vacuum cleaner fan, which is improved in particular with regard to the durability of the storage and / or with respect to the vibration transmission to the housing.

Inventive solution

The reference numbers in all claims have no limiting effect, but are only intended to improve their readability.

The solution of the problem is achieved by a vacuum cleaner fan with the features of claim 1.

An inventive vacuum cleaner fan comprises a housing which can be fixedly mounted in a vacuum cleaner housing or, for example, is a part of the vacuum cleaner housing or can be integrated in this. The vacuum cleaner fan serves to generate a suction air flow and generates for this purpose in particular a negative pressure. The housing may include means for guiding the suction air flow. The vacuum cleaner fan further includes an electric motor having a motor shaft carrying a rotor. The vacuum cleaner fan further includes a driven by the electric motor fan, which is in particular fixedly mounted on the motor shaft and which is designed to generate the suction air flow or the negative pressure. The motor shaft is mounted in two ball bearings, which are axially spaced from each other. In particular, a first ball bearing is arranged in an end region of the motor shaft in which the fan wheel is fastened, and a second ball bearing in an end region of the motor shaft opposite this end. The first ball bearing comprises an inner ring and an outer ring, between the rolling elements, in particular balls, are mounted. The ball bearing is preferably designed as a deep groove ball bearing. The inner ring of the first ball bearing is firmly connected to the motor shaft and sits without play on this. The inner ring may for example be firmly connected to the motor shaft by gluing or by a play-free fit.

According to the invention, the outer ring of the first ball bearing is supported on an axial outer surface via an elastic damping element in a bearing seat connected to the housing. In particular, the outer ring in the axial direction against a surface of the bearing seat supported or held over the elastic damping element in the axial direction. The bearing seat may be formed directly in the housing or formed by a component connected to the housing, such as a guide for guiding the air flow generated by the fan. Furthermore, according to the invention, the outer ring of the first ball bearing is mounted with radial clearance in the bearing seat, that a radial outer surface of the outer ring of the first ball bearing is arranged without contact with the bearing seat. In the radial direction, that is, in a plane which is perpendicular to the longitudinal axis of the motor shaft, the first ball bearing is thus freely movable or elastically held only on the fitting on the axial outer surface of the outer ring elastic damping element.

Characterized in that the outer ring of the first ball bearing is supported on an axial outer surface via an elastic damping element, the coupling of axial vibrations in the bearing seat and thus in the housing can be largely suppressed. Furthermore, the coupling of vibrations in the radial direction can be largely avoided by the fact that the radial outer surface does not touch the bearing seat. Furthermore, as a result of the fact that the outer ring of the first ball bearing is mechanically connected only via the elastic damping element to the bearing seat, rotation of the motor shaft about a center of mass is possible at rotational speeds above a critical speed, even if it is not located on the longitudinal axis of the motor shaft. The center of mass is the center of mass or the center of gravity of the rotor, which comprises the motor shaft and the rotor, as well as the other components which are firmly connected and co-rotating with the motor shaft, ie. in particular the fan wheel and the inner rings of the ball bearings. The critical speed may be, for example, at about 20,000 rpm, with a speed of, for example, up to 60,000 rpm can be achieved during operation. At operating speed of the engine, a high smoothness of the vacuum cleaner fan can be achieved in this way, whereby the coupling of structure-borne noise is further reduced in the housing.

Preferred embodiment of the invention

Advantageous embodiments and developments, which can be used individually or in combination with each other, are the subject of the dependent claims.

According to a preferred embodiment of the invention, the first ball bearing is arranged close to that end of the motor shaft which carries the fan, and a second ball bearing is arranged on the opposite end of the fan wheel of the motor shaft, wherein an inner ring of the second ball bearing fixed to the motor shaft and a Outer ring of the second ball bearing is firmly connected to the housing. The inner ring may for example be glued to the motor shaft or fixed with a play-free fit on this, and the outer ring may in particular be glued to a further bearing seat of the housing. As a result, the opposite end of the fan wheel of the motor shaft in the axial and radial direction backlash against the housing of the vacuum cleaner fan is stored. Together with the described floating bearing of the first ball bearing, this results in a specific in the axial direction, but in the radial direction in the area of the fan movable mounting. As a result, a sufficiently high rigidity of the bearing can be achieved in a simple manner with a high level of smoothness of the vacuum cleaner fan.

Furthermore, it is preferred that the second ball bearing exerts an axially directed force on the motor shaft, through which the outer ring of the first ball bearing is pressed against the elastic damping element and / or this is pressed against the bearing surface of the bearing seat. By such a position, which may be formed in particular as an O-position, the first ball bearing is loaded in the axial direction such that the elastic damping element is held between a bearing surface of the bearing seat and the axial outer surface of the outer ring of the first ball bearing. As a result, the axial fixing of the storage is further improved. Furthermore, this increases the static friction between the outer ring of the first ball bearing or the bearing seat and the elastic damping element, whereby sliding friction, which could occur due to the radial mobility of the outer ring, is reliably avoided. As a result, the durability of the storage can be further increased.

Preferably, the vacuum cleaner fan, in particular the fan and a nozzle of the housing, is designed such that when the fan is driven to generate a negative pressure, this exerts an axial force on the motor shaft through which the outer ring of the first ball bearing to the elastic damping element and this is pressed into the bearing seat or on the bearing surface. As a result, the axial position of the motor shaft is set more precisely and increases the static friction between the elastic damping element and the outer ring of the first ball bearing or the bearing surface, whereby the durability is improved.

In a particularly preferred manner, the employment of the first and the second ball bearing and the negative pressure generated by the fan to increase the pressing force exerted by the outer ring of the first ball bearing on the damping element, together. The axial outer side of the outer ring of the first ball bearing is in this case the fan wheel facing side of the outer ring, and the employment of the ball bearing corresponds to an O-employment. As a result, the durability can be further increased.

Preferably, the elastic damping element is designed such that it allows an axial and a radial movement of the outer ring of the first ball bearing relative to the bearing seat. In particular, the elastic damping element is designed to be elastic so that even if the outer ring of the first ball bearing rests firmly with its axial outside on one side of the elastic damping element and the elastic damping element with its other side firmly against a bearing surface of the bearing seat, a radial movement the outer ring can be made relative to the bearing seat. The solid concerns of the damping element on the bearing surface or on the axial outer side of the outer ring can be achieved by cohesive, positive and / or non-positive connection. Thus, in particular, no cohesive connection of the elastic damping element with the bearing seat and the outer ring is required, but it can be held by friction, for example, by the force exerted by the outer ring on the damping element pressing force the damping element. Characterized in that the elastic damping element by deformation allows axial and radial movement of the outer ring relative to the bearing seat, sliding friction between the elastic damping element and the bearing seat and / or the outer ring can be avoided and thereby the durability of the storage can be increased.

According to a preferred embodiment of the invention, the elastic damping element is formed as a disc which is arranged between the axial outside, in particular between an axial end wall of the outer ring or a sealing disc of the first ball bearing, and a bearing surface of the bearing seat. As a result, a support of the outer ring of the first ball bearing with the interposition of the elastic damping element against the bearing seat is made possible in a particularly simple manner. The elastic damping element may be formed as a separate component. In a further advantageous manner, the elastic damping element can be connected to the outer ring, for example, adhered to the axial outer side of the outer ring or on a sealing disc connected thereto. As a result, the assembly of the bearing assembly is facilitated in such a way that the motor shaft can be used with the seated on this first ball bearing and connected to the outer ring of the first ball bearing elastic damping element in the bearing seat.

Furthermore, it is preferred that the elastic damping element is integrally formed on a sealing disc of the first ball bearing. The sealing disc is fixedly connected to the outer ring of the first ball bearing and may consist of an elastic material or be coated by such. Characterized in that the elastic damping element is formed integrally with the sealing disc, the manufacture and assembly of the elastic damping element are further simplified.

According to preferred embodiments of the invention, the elastic damping element is flush with the outside of the outer ring of the first ball bearing or projects beyond it. Depending on the design of the bearing seat, a particularly simple assembly can thereby be made possible, wherein at the same time when inserting the first ball bearing in the bearing seat centering, which ensures that the outer side of the outer ring does not touch the bearing seat. A flush with the outer side of the outer ring design of the elastic damping element is preferred when the bearing seat is formed frusto-conical, wherein the outer diameter of the elastic damping element corresponds approximately to the inner diameter of the cone in the area of this final bearing surface. That the elastic damping element projects beyond an axial extension of the outer side of the outer ring is preferred when the bearing seat is cylindrical. In this case, the outer diameter of the elastic damping element substantially corresponds to the inner diameter of the cylinder. In both cases, it can be ensured in a simple manner that the outer ring of the first ball bearing is arranged without contact within the bearing seat.

The elastic damping element is designed in particular as an annular disc with a rectangular, round or semicircular cross-sectional shape. As a result, in a simple manner, a support against a bearing surface of the bearing seat allows a radial mobility of the outer ring of the first ball bearing and possibly a centering in the bearing seat.

In an advantageous manner, the elastic damping element may have a profiled surface, which in particular forms elevations, such as nubs, points or points. Alternatively or additionally, the axial outer surface of the outer ring or the surface of the bearing surface of the bearing seat can be profiled. As a result, the static friction with the bearing surface of the bearing seat and / or the axial outer surface of the outer ring of the first ball bearing increases and a secure frictional engagement can be ensured.

In a particularly preferred manner, the elastic damping element on one or both sides of a profiled surface, which corresponds to a profiled surface of the bearing surface of the bearing seat and / or the outer side of the outer ring, so that elevations of one surface in depressions of the other can be used. As a result, the correct position assembly of the elastic damping element or provided with this ball bearing facilitates and centering causes and the frictional engagement can be further improved.

Brief description of the drawings

Further advantageous embodiments will be described in more detail below with reference to three exemplary embodiments illustrated in the drawings, to which the invention is not limited.

They show schematically:

1a and 1b a part of a vacuum cleaner fan according to the prior art in a partially sectioned view, wherein 1b an enlarged section 1a shows;

2 a first embodiment of the invention in one of 1b corresponding view;

3 a second embodiment of the invention in a sectional view;
and finally

4 a ball bearing used in an A-bearing according to a third embodiment of the vacuum cleaner fan according to the invention in a sectional view.

Detailed description based on three embodiments

In the following description of two preferred embodiments of the present invention, like reference characters designate like or similar components. For clarity, not all figures are shown in all figures.

In 1a and 1b is shown in schematic form part of a vacuum cleaner fan according to a prior art. The fan wheel 1 , which is designed to generate a negative pressure, sits firmly on the motor shaft 2 a drive motor that continues to drive on the motor shaft 2 sitting runner 3 includes, which cooperates with a stator of the motor, not shown. The motor shaft 2 is in the area of that end, which is the fan 1 carries in a first ball bearing 4 stored, which is also referred to as A-bearing. The opposite end of the motor shaft is in a second ball bearing 5 stored, which is referred to as B-bearing. The first ball bearing 4 includes an inner ring 6 that stuck on the motor shaft 2 sits, and an outer ring 7 between which in a cage the balls 8th are arranged of the ball bearing. The outer ring is free of play in the diffuser 9 held, which is firmly connected to the housing, not shown, of the vacuum cleaner fan and to guide the of the fan 1 generated air flow is formed. The second ball bearing 5 has an inner ring 10 and an outer ring 11 on, between those in a cage the bullets 12 of the ball bearing. The first and second ball bearings 4 . 5 are designed as deep groove ball bearings, wherein the grooves in which the balls 8th . 12 are guided, are not shown for simplicity. During assembly, the outer ring 11 of the second ball bearing 5 through a cone spring 13 burdened by a hiring of the second ball bearing 5 against the first ball bearing 4 to bias this form of O-attitude against each other, wherein the force action lines corresponding to the O-employment, in 1a dash-dotted lines are indicated. After that, the outer ring 11 of the second ball bearing 5 fixed in a bearing seat, not shown, of the housing by gluing. The longitudinal axis of the motor shaft 2 is with the reference numeral 14 designated.

The area of the first ball bearing 4 (A-bearing) according to the in 1a illustrated prior art is enlarged in 1b shown. The inner ring 6 of the first ball bearing 4 is between a level 15 the motor shaft 2 and a flange 16 that's the fan 1 carries (see 1a ), fixed, in particular rotationally fixed and axial and radial backlash with a tight fit on the motor shaft 2 placed. The diffuser 9 has a bearing seat 17 on, passing through a perpendicular to the longitudinal axis of the motor shaft 2 standing storage area 18 and a frusto-conical bearing wall 19 is formed. The outer ring 7 of the first ball bearing 4 is with his front wall 20 that has an axial outside of the outer ring 7 forms, against the storage area 18 stated. Between a radial outside 21 of the outer ring 7 and the frusto-conical bearing wall 19 remains a wedge-shaped tapered gap 22 , which fixes the outer ring 7 in the camp seat 17 of the distributor 9 filled with adhesive.

In 2 is an embodiment of the invention in one of 1b corresponding representation shown. It is between the front wall 20 of the outer ring 7 of the first ball bearing 4 and the storage area 18 of the bearing seat 17 an annular damping element 23 used. The front wall 20 is therefore not directly on the storage area 18 but only via the damping element 23 , Between the radial outside 21 of the outer ring 7 and the conical bearing wall 19 the gap remains 22 which is not filled with adhesive. Since the damping element the end wall 20 of the outer ring 7 at a distance to the storage area 18 holds, is the outer ring 7 without touching its radial outside 21 with the bearing seat 17 held. The first ball bearing is thus radially loose or with a clearance fit in the bearing seat 17 used. To facilitate assembly, the gap 22 wedge-shaped. By the O-employment of the camps 4 . 5 becomes the outer ring 7 against the damping element 23 and this against the storage area 18 pressed. This allows the damping element 23 be held in position without gluing. An additional contact force is created by the negative pressure of the fan 1 is generated and by the on the motor shaft 2 a force acting in the direction indicated by the arrow is exerted. Incidentally, this is in 2 illustrated embodiment of the invention as in 1a shown formed.

The interposition of the damping element 23 between the front wall 20 of the outer ring 7 and the storage area 18 allows axial mobility of the outer ring 7 and thereby minimizing the axially transmitted vibrations. The missing radial connection of the radial outside 21 of the outer ring 17 of the first ball bearing 4 ensures that no radial vibrations on the diffuser 9 be transmitted. The elastic bearing also causes a shift of the critical speed towards low speeds, for example about 15000 1 / min and allows the bearing centering in the conical bearing wall 19 at speeds greater than the critical speed. The bias due to the O-position and the additional force due to the generated negative pressure press the damping element 23 together. The static friction between the bearing surface 18 and the damping element 23 and / or between the damping element 23 and the front wall 20 of the outer ring 7 of the first ball bearing 4 ensure that the outer ring 7 within the nozzle 9 resting and not from the rotation of the inner ring 6 taken, which would result in a reduction in durability.

If the speed is far above the critical speed, the motor shaft centers itself, ie the center of gravity approaches the axis of rotation; the motor shaft stabilizes and the vacuum cleaner fan runs quieter. This effect is independent of the exact installation position of the shaft and of other forces acting on the shaft. The vibrations transmitted radially from the first ball bearing to the housing can thereby be at operating speed to, for example, 1/5 compared to in FIG 1a and 1b state of the art reduce, almost regardless of which unbalance the motor shaft 2 has with the co-rotating components. Accordingly, a significant reduction of the sound power level can be achieved.

A sectional view of a second embodiment of the invention gives 3 again. As in 3 can be seen, covers the damping element 23 the storage area 18 largely, the outer edge of the damping element 23 slightly above the outer contour of the outer ring 7 protrudes. The damping element 23 is before mounting with the outer ring 7 or the sealing washer 24 of the first ball bearing 4 have been connected, for example, or sprayed on. During assembly, the outer ring 7 with the damping element 23 in the camp seat 17 introduced. The warehouse wall 19 is funnel-shaped in a front part to the insertion of the first ball bearing 4 with the damping element mounted thereon 23 in the camp seat 17 to facilitate. In the back part is the storage wall 19 cylindrically shaped. The supernatant of the damping element 23 over the radial outside 21 of the outer ring 7 ensures that between the radial outside 21 and the storage wall 19 a gap remains and the outer ring 7 radially the bearing wall 19 not touched. Incidentally, the second embodiment is formed as the first.

The damping element is designed in the described embodiments as a silicone rubber ring with an outer diameter of about 22 mm, an inner diameter of about 16 mm and a thickness of about 0.5 mm.

In 4 is an education of the first ball bearing 4 with a one-piece with a sealing washer 24 executed damping element 23 enlarged shown in section. The sealing washer 24 seals the cage 25 in which the balls 8th run outward and out with the outer ring 7 firmly, in particular rotationally fixed, connected. On the inner ring 6 is the sealing washer in sealing grooves 26 slidably mounted. The damping element 23 is with the gasket 24 over a connection area 27 integrally connected. The damping element is flush with the outside 21 of the outer ring 7 off or ends slightly within an extension of the outside 21 and is designed as a ring with a thickness of about 0.3 mm and an outer diameter of about 22 mm, of which the outer ring 7 facing away, substantially flat surface has an inner diameter of about 19 mm. Incidentally, a vacuum cleaner fan according to this embodiment of the invention is constructed like the first embodiment described above.

The features disclosed in the foregoing description, the claims and the drawings can be used individually or in any combination for the realization of the invention in their different configurations of importance.

LIST OF REFERENCE NUMBERS

1

 fan

2

 motor shaft

3

 runner

4

 First ball bearing

5

 Second ball bearing

6

 inner ring

7

 outer ring

8th

 Bullet

9

 diffuser

10

 inner ring

11

 outer ring

12

 Bullet

13

 conical spring

14

 longitudinal axis

15

 step

16

 flange

17

 bearing seat

18

 storage area

19

 bearing wall

20

 bulkhead

21

 outside

22

 gap

23

 damping element

24

 sealing washer

25

 Cage

26

 seal groove

27

 connecting area

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 4969797 [0004]
• WO 2005/029680 A1 [0005]

Claims (12)

Vacuum cleaner fan, comprising a housing, an electric motor with a motor shaft ( 2 ) as well as a fan wheel ( 1 ) mounted on the motor shaft ( 2 ), wherein the motor shaft ( 2 ) is rotatably mounted with two axially spaced ball bearings relative to the housing and wherein an inner ring ( 6 ) of a first ball bearing ( 4 ) fixed to the motor shaft ( 2 ), characterized in that an outer ring ( 7 ) of the first ball bearing ( 4 ) in the axial direction via an elastic damping element ( 23 ) against a storage area ( 18 ) of a bearing seat ( 17 ) and in the radial direction without contact with the bearing seat ( 17 ) is arranged. Vacuum cleaner fan according to claim 1, characterized in that the first ball bearing ( 4 ) in one the fan wheel ( 1 ) carrying end portion of the motor shaft ( 2 ) and a second ball bearing ( 5 ) at an opposite end of the motor shaft ( 2 ), wherein an inner ring ( 10 ) of the second ball bearing ( 5 ) fixed to the motor shaft ( 2 ) and an outer ring ( 11 ) of the second ball bearing ( 5 ) is firmly connected to the housing. Vacuum cleaner fan according to claim 2, characterized in that the second ball bearing ( 5 ) such a directed axial force on the motor shaft ( 2 ) exerts that the outer ring ( 7 ) of the first ball bearing ( 4 ) to the elastic damping element ( 23 ) and / or the elastic damping element ( 23 ) against the storage area ( 18 ) of the bearing seat ( 17 ) is pressed. Vacuum cleaner fan according to one of the preceding claims, characterized in that the fan wheel ( 1 ) and the housing are designed such that when the fan wheel ( 1 ) is driven, this such a directed axial force on the motor shaft ( 2 ) exerts that the outer ring ( 7 ) of the first ball bearing ( 4 ) to the elastic damping element ( 23 ) and / or the elastic damping element ( 23 ) to the storage area ( 18 ) of the bearing seat ( 17 ) is pressed. Vacuum cleaner fan according to one of the preceding claims, characterized in that the elastic damping element ( 23 ) is formed such that an axial and a radial movement of the outer ring ( 7 ) relative to the bearing seat ( 17 ). Vacuum cleaner fan according to one of the preceding claims, characterized in that the elastic damping element ( 23 ) as one between an axial end wall ( 20 ) of the outer ring ( 7 ) of the first ball bearing ( 4 ) and the storage area ( 18 ) of the bearing seat ( 17 ) arranged disc is formed. Vacuum cleaner fan according to one of the preceding claims, characterized in that the elastic damping element ( 23 ) with the outer ring ( 7 ) of the first ball bearing ( 4 ) connected is. Vacuum cleaner fan according to claim 7, characterized in that the elastic damping element ( 23 ) in one piece to a sealing disc ( 24 ) of the first ball bearing ( 4 ) is formed. Vacuum cleaner fan according to one of the preceding claims, characterized in that the elastic damping element ( 23 ) flush with a radial outside ( 21 ) of the outer ring ( 7 ) of the first ball bearing ( 4 ) or over this projects. Vacuum cleaner fan according to one of the preceding claims, characterized in that the elastic damping element ( 23 ) is formed as an annular disc having a rectangular, round or semi-circular cross-sectional shape. Vacuum cleaner fan according to one of the preceding claims, characterized in that the elastic damping element ( 23 ) at its to the storage area ( 18 ) and / or to the outer ring ( 7 ) of the first ball bearing ( 4 ) directed surface is profiled. Vacuum cleaner fan according to one of the preceding claims, characterized in that the bearing surface ( 18 ) and / or an axial end wall ( 20 ) of the outer ring ( 7 ) of the first ball bearing ( 4 ) is profiled.

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