EP3786333B1 - Device for compensating for an imbalance in a loaded washing drum - Google Patents

Description

The invention relates to a device for compensating for an imbalance in a loaded laundry drum of an appliance for treating laundry, having at least one ring-shaped hollow body arranged concentrically to an axis of rotation of the laundry drum and several compensating balls accommodated in the hollow body in a movable manner and in a row. The invention also relates to a laundry drum comprising at least one such device for compensating for an imbalance in the loaded laundry drum. Furthermore, the invention relates to a method for producing a compensating ball for a device for compensating for an imbalance in a loaded laundry drum of an appliance for treating laundry, wherein the compensating ball can be arranged movably in a ring-shaped hollow body which is arranged concentrically to an axis of rotation of the laundry drum. The invention also relates to a method for producing a noise reduction element for a device for compensating for an imbalance in a loaded laundry drum of an appliance for treating laundry, wherein the noise reduction element can be arranged in series between a pair of metal balls which are movable and in series in an annular hollow body are included, which is arranged concentrically to an axis of rotation of the laundry drum.

A device of the type mentioned is for example DE 10 2014 221 348 A1 known. In such a device, an imbalance in a laundry drum loaded with laundry is reduced by eccentricity compensation, in that the metal balls of the device are automatically arranged diametrically opposite the imbalance within the ring-shaped hollow body connected to the laundry drum with respect to the axis of rotation of the laundry drum. The hollow body can be attached to a front side or a back side of the laundry drum and is filled both with the metal balls and also partially with a damping fluid. A quantity and the viscosity of the damping fluid have a decisive influence on the behavior of the device in a sub-critical speed range ≤ about 100 rpm. As a rule, the damping fluid is a silicone oil, since a silicone oil has a very good viscosity/temperature behavior.

If the laundry drum and thus the device are operated in the subcritical speed range, the metal balls still have a speed relative to the hollow body. When combined with a hollow body made of plastic, this relative speed leads to running noises that can be annoying. If a higher-viscosity oil is used as the damping fluid and if there are small gaps between the metal balls and the hollow body, the metal balls are already carried along during start-up or at very low speeds. When starting and braking the laundry drum, the inertia of the metal balls can also lead to undesirable collision noises.

In order to reduce the corresponding operating noise, the metal balls are off DE 10 2014 221 348 A1 covered with a layer of plastic. According to CN 202 116 870 U Smaller balls made of plastic or rubber are placed between the metal balls to reduce noise. KR 10 2007 115 293 A and KR 10 2005 110 071 A each propose to reduce noise, to provide a running surface of the hollow body with an elastic coating. On the other hand beats KR 10 2007 115 289 A the arrangement of elastic balls between the metal balls to reduce noise. According to KR 10 2007 115 285 A there are solid cylinders instead of metal balls to reduce operating noise. According to U.S. 3,321,997A a compensating ring is inserted within an annular cavity, which is formed alternately from metallic compensating elements and damping elements.

One object of the invention is to reduce disruptive operating noises from an appliance for treating laundry, which is equipped with a device mentioned at the outset, particularly in a supercritical speed range.

This object is solved by the independent patent claims. Advantageous configurations are presented in the following description, the dependent patent claims and the figures, whereby these configurations, taken individually or in various combinations of at least two of these configurations with one another, can represent a further developing, in particular also preferred or advantageous, aspect of the invention. Configurations of the device can Correspond to configurations of the method, and vice versa, even if this is not explicitly referred to in the following in individual cases.

A device according to the invention for compensating for an imbalance in a loaded laundry drum of an appliance for treating laundry has at least one ring-shaped hollow body arranged concentrically to an axis of rotation of the laundry drum and several compensating balls accommodated in the hollow body in a movable manner and in a row. At least one compensating ball is designed as a composite body made up of a metal ball, a foam coating enclosing the metal ball and a plastic coating enclosing the foam coating. Alternatively or additionally, at least one compensating ball has a surface structure. Alternatively or additionally, between each pair of compensating balls there is a noise reduction element designed as a hollow cylinder, which is at least partially made of an elastomer and whose longitudinal center axis runs tangentially to the hollow body.

According to the invention, at least one compensating ball is designed as a composite body made up of a metal ball, a foam coating surrounding the metal ball and a plastic coating surrounding the foam coating. The composite body thus has a sandwich structure made of materials with different properties, as a result of which the properties of the compensating ball can be optimally and diversely adapted to the respective technical requirements. In the case of a collision in the circumferential direction of the hollow body between two correspondingly designed compensating balls on the one hand or a compensating ball according to the invention and a conventional metal ball on the other hand, the foam coating absorbs the kinetic energy of the collision. The foam coating also suppresses noise emissions, which is accompanied by a significant noise reduction. The plastic coating protects the foam coating from mechanical damage, in particular from wear and tear caused by contact with other objects. The metal sphere can be a solid sphere or a hollow sphere. The metal ball can be a steel ball, for example. The plastic coating can be partially or completely made of an elastomer or rubber. There can also be two or more, in particular all Balancing balls of the device can be designed according to the invention.

In a special embodiment of the invention, at least one compensating ball has a surface structure. In this way, the natural frequency of the compensating ball can be changed or set so that the natural frequency is no longer perceived as disturbing when two correspondingly designed compensating balls collide, or a compensating ball according to the invention and a conventional metal ball. The surface structuring allows a sound design or a trimming of a sound image of the compensating sphere by changing or adjusting an oscillation frequency occurring in a collision and an oscillation amplitude of the compensating sphere. The balance ball then emits a noise-reducing bounce response in the event of a collision. Two or more, in particular all, compensating balls of the device can also be designed according to this embodiment.

According to a particular embodiment of the invention, a compensating ball is obtained which is designed as a composite body of a metal ball, a foam coating enclosing the metal ball and a plastic coating enclosing the foam coating and is provided with a surface structure. The surface structuring can be produced solely by structuring the plastic coating, by joint structuring of the plastic coating and the foam coating, or by joint structuring of the plastic coating, the foam coating and the metal ball.

In an alternative not forming part of the present invention is between each pair of balancing balls in each case a noise reduction element designed as a hollow cylinder is arranged, the longitudinal central axis of which runs tangentially to the hollow body. The inventive design and arrangement of the respective noise reduction element in the hollow body, the noise reduction element can be flowed through by a damping fluid present in the hollow body and thus has a low flow resistance for the damping fluid, so that the properties and the function of the damping fluid are largely not affected by the noise reduction element or is. An axial length and an outer diameter of the respective noise reduction element are preferably matched to the shape of the hollow body in such a way that the noise reduction element cannot cant within the hollow body. The hollow cylinder can be made partially or completely from a plastic, for example an elastomer or rubber. The respective noise-reduction element prevents compensating balls arranged adjacent to the noise-reducing element from colliding, which is particularly advantageous if the compensating balls are designed as simple metal balls.

The hollow body is designed as a hollow ring. The hollow body can be fixed on the laundry drum, for example on a front side having a loading opening or on a rear side of the laundry drum opposite the front side. The hollow body can be made partially or completely from a metallic material, a plastic or a fiber composite material. The hollow body is partially filled with a damping fluid. The device according to the invention can also have two or more corresponding hollow bodies with compensating balls accommodated therein.

The appliance for treating laundry can be designed as a front loader, for example. The device can be a washing machine or a spin dryer, for example. A device according to the invention has at least one device according to the invention for compensating for an imbalance in the unit formed from the laundry and the laundry drum caused by an uneven loading of the laundry drum with laundry to be treated. The device minimizes running noise and noise from the impact of the compensating balls. In addition, due to the reduction in operating noise according to the invention, damping fluids, in particular oils, with a lower viscosity can be used, which above all reduce measuring times for imbalance control methods.

According to an advantageous embodiment, the foam coating is produced by overmolding the metal ball with a foam. This makes mass production of the balancing balls possible. After the foam coating has been produced accordingly, the foam coating can be overmoulded with a plastic, for example, in order to produce the plastic coating and ultimately the compensating ball.

According to a further advantageous embodiment, the foam coating is produced by gluing foam beads onto the metal ball. For this purpose, the metal ball can be wetted with an adhesive beforehand. The foam beads can then be glued to the surface of the metal ball that has been wetted with the adhesive. After this production of the foam coating, the foam coating can be overmoulded with a plastic, for example, in order to produce the plastic coating and ultimately the compensating ball.

According to a further advantageous embodiment, the surface structure has a large number of surface depressions. For example, the compensating ball can have a surface corresponding to a golf ball. The number of surface indentations and the indentation pattern formed by the surface indentations are preferably chosen such that natural frequencies of the balance ball are changed to reduce noise.

According to a further advantageous embodiment, at least one surface depression is designed as a bore or as a trough. The hole and/or the trough can be produced by machining or by plastic deformation of the compensating ball. The compensating ball can also have both at least one bore and at least one trough. The number of bores and/or depressions and the depression pattern formed by the bores and/or depressions are preferably selected in such a way that natural frequencies of the compensating ball are changed to reduce noise.

According to a further advantageous embodiment, at least two surface depressions differ from one another in terms of their shapes. The combination and number the different and the identically designed surface depressions are preferably selected in such a way that natural frequencies of the balancing ball are changed to reduce noise.

According to a laundry drum according to the invention, this comprises at least one device according to the invention for compensating for an imbalance. The laundry drum particularly preferably has two such devices, which are each arranged on the base and front base of a cylindrical laundry drum. The two devices for compensating for an imbalance are therefore arranged on the laundry drum at the greatest possible distance from one another, which enables particularly good compensation for an imbalance that can be caused by laundry located in the laundry drum and between the devices.

According to a method according to the invention for producing a compensating ball for a device for compensating for an imbalance in a loaded laundry drum of an appliance for treating laundry, the compensating ball being movably arrangeable in a ring-shaped hollow body which is arranged concentrically to an axis of rotation of the laundry drum, the compensating ball by coating a metal ball with a foam coating and coating the foam coating arranged on the metal ball with a plastic coating.

According to a special embodiment, the compensating ball is produced by producing a ball with a surface structure.

The advantages mentioned above in relation to the device are correspondingly associated with the method.

According to an advantageous embodiment, the foam coating is produced by overmolding the metal ball with a foam. The advantages mentioned above with reference to the corresponding configuration of the device are correspondingly associated with this configuration.

According to a further advantageous embodiment, the foam coating is produced by wetting a surface of the metal ball with an adhesive and by applying foam beads to the surface wetted with the adhesive. The advantages mentioned above with reference to the corresponding configuration of the device are correspondingly associated with this configuration.

According to a further advantageous embodiment, the surface structuring is produced with a large number of surface indentations, at least one surface indentation being produced by a machining operation or an embossing operation. The advantages mentioned above with reference to the corresponding configuration of the device are correspondingly associated with this configuration. In particular, surface depressions in the form of bores and/or depressions can be formed in this way.

According to a further advantageous embodiment, the surface structure is produced with at least two differently designed surface depressions. The advantages mentioned above with reference to the corresponding configuration of the device are correspondingly associated with this configuration.

According to a further method for producing a noise reduction element for a device for compensating for an imbalance of a loaded laundry drum of an appliance for treating laundry, wherein the noise reduction element can be arranged in series between a pair of balancing balls which are movably and in series accommodated in a ring-shaped hollow body , which is arranged concentrically to an axis of rotation of the laundry drum, the noise reduction element is produced by producing a hollow cylinder whose outer diameter is smaller than an inside cross-sectional width of the hollow body.

According to a further embodiment, the noise reduction element is made at least partially from an elastomer. The advantages mentioned above with reference to the corresponding configuration of the device are correspondingly associated with this configuration.

Fig. 1

eine schematische Schnittdarstellung eines Ausführungsbeispiels für eine erfindungsgemäße Ausgleichskugel;

Fig. 2

eine schematische Darstellung eines weiteren Ausführungsbeispiels für eine erfindungsgemäße Ausgleichskugel; und

Fig. 3

eine schematische Darstellung eines Abschnitts eines Ausführungsbeispiels für eine Vorrichtung, die nicht Teil der Erfindung ist.

In the following, the invention is explained by way of example with reference to the attached figures using preferred embodiments. Show it:

1

a schematic sectional view of an embodiment of a compensating ball according to the invention;

2

a schematic representation of a further embodiment of a compensating ball according to the invention; and

3

a schematic representation of a portion of an embodiment for a device which is not part of the invention.

Identical or functionally identical components are provided with the same reference symbols in the figures. A repeated description of such components can be omitted in the following description of the figures.

1 shows a schematic sectional view of an exemplary embodiment of a compensating ball 1 according to the invention for a device, not shown, for compensating for an imbalance in a loaded laundry drum, not shown, of a device for treating laundry, not shown, the device having at least one annular arrangement arranged concentrically to an axis of rotation, not shown, of the laundry drum formed hollow body, not shown, and a plurality of compensating balls 1 accommodated movably and in series in the hollow body, of which in 1 only one compensating ball 1 is shown.

The compensating ball 1 is designed as a composite body made up of a metal ball 2 , a foam coating 3 enclosing the metal ball 2 and a plastic coating 4 enclosing the foam coating 3 . The foam coating 3 can be produced by overmolding the metal sphere 2 with a foam or by gluing foam beads onto the metal sphere 2 .

2 shows a schematic representation of a further exemplary embodiment of a compensating ball 5 according to the invention for a device (not shown) for compensating for an imbalance in a loaded laundry drum (not shown). Appliance for treating laundry, the device having at least one ring-shaped hollow body, not shown, arranged concentrically to an axis of rotation (not shown) of the laundry drum and a plurality of compensating balls 5 accommodated movably and in a row in the hollow body, of which in 1 only one compensating ball 5 is shown.

The compensating ball 5 has a surface structure 6, which has a large number of surface depressions 7, each of which is designed as a bore or as a trough. At least two surface depressions 7 can differ from one another in their shapes.

3 shows a schematic representation of a section of an embodiment of a device 8 for compensating for an imbalance of a loaded laundry drum (not shown) of a device (not shown) for treating laundry.

The device 8 has a ring-shaped hollow body 8 arranged concentrically to an axis of rotation (not shown) of the laundry drum, from which in 3 only a portion is shown.

Furthermore, the device 8 has a plurality of compensating balls 10, which are accommodated in a row in the hollow body 9 and are movable and which are each designed as a simple metal ball and of which 3 only one pair is shown. A noise reduction element 11 designed as a hollow cylinder is arranged between each pair of compensating balls 10 , the longitudinal central axis 12 of which runs tangentially to the hollow body 9 . The noise reduction element 11 is made entirely of an elastomer. An axial length L and an outer diameter D of the noise reduction element 11 are matched to the shape of the hollow body 9 in such a way that the noise reduction element 11 cannot tilt within the hollow body 9 .

Reference list:

1

balancing ball

2

metal ball

3

foam coating

4

plastic coating

5

balancing ball

6

surface texturing

7

surface indentation

8th

contraption

9

hollow body

10

balancing ball

11

noise reduction element

12

Longitudinal center line of 11

L

length of 11

D

outside diameter of 11

Claims (14)

1. Apparatus (8) for compensating for an imbalance of a loaded laundry drum of an appliance for the treatment of laundry, having at least one hollow body (9), which is arranged concentrically in relation to an axis of rotation of the laundry drum and is embodied in an annular manner, and a plurality of compensating spheres (1, 5, 10), which are accommodated such that they can move and are in series in the hollow body (9), characterised in that at least one compensating sphere (1, 5, 10) is embodied as a composite body made of a metal sphere (2), a foam coating (3) surrounding the metal sphere (2) and a plastic coating (4) surrounding the foam coating (3).
2. Apparatus (8) according to claim 1, characterised in that the foam coating (3) is produced by encapsulating the metal sphere (2) with a foam.
3. Apparatus (8) according to claim 1, characterised in that the foam coating (3) is produced by adhesively bonding foam beads onto the metal sphere (2).
4. Apparatus (8) according to one of claims 1 to 3, characterised in that at least one compensating sphere (1, 5, 10) has a surface structuring (6).
5. Apparatus (8) according to claim 4, characterised in that the surface structuring (6) has a large number of surface depressions (7).
6. Apparatus (8) according to claim 5, characterised in that at least one surface depression (7) is embodied as a bore hole or cavity.
7. Apparatus (8) according to claim 5 or 6, characterised in that at least two surface depressions (7) differ from one another in their shapes.
8. Laundry drum of an appliance for the treatment of laundry, characterised in that the laundry drum comprises at least one apparatus according to one of claims 1 to 7.
9. Method for producing a compensating sphere (1, 5) for an apparatus (8) for compensating for an imbalance of a loaded laundry drum of an appliance for the treatment of laundry, wherein the compensating sphere can be arranged such that it can move in a hollow body (9), which is embodied in an annular manner and is arranged concentrically in relation to an axis of rotation of the laundry drum, characterised in that the compensating sphere (1, 5) is produced by coating a metal sphere (2) with a foam coating (3) and coating the foam coating (3) arranged on the metal sphere (2) with a plastic coating (4).
10. Method according to claim 9, characterised in that the foam coating (3) is produced by encapsulating the metal sphere (2) with a foam.
11. Method according to claim 9, characterised in that the foam coating (3) is produced by wetting a surface of the metal sphere (2) with an adhesive and by applying foam beads to the surface that has been wetted with the adhesive.
12. Method according to one of claims 9 to 11, characterised in that a surface structuring (6) is generated solely by a structuring of the plastic coating (4), by a common structuring of the plastic coating (4) and the foam coating (3) or by a common structuring of the plastic coating (4), the foam coating (3) and the metal sphere (2).
13. Method according to claim 12, characterised in that the surface structuring (6) is produced by a large number of surface depressions (7), wherein at least one surface depression (7) is produced by a boring procedure or a stamping procedure.
14. Method according to claim 13, characterised in that the surface structuring (6) is produced by at least two surface depressions (7) embodied in differing manners.

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