EP4039863B1 - Method for producing a shell wall for a laundry drum with a compensation arrangement, casing wall for a laundry drum and laundry drum - Google Patents

Description

One aspect of the invention relates to a method for producing a casing wall for a laundry drum for a household appliance for the care of laundry items. Another aspect of the invention relates to a casing wall for a laundry drum. Another aspect of the invention relates to a laundry drum for a household appliance for the care of laundry items. Yet another aspect of the invention relates to a household appliance for the care of laundry items with a laundry drum.

Household appliances for washing laundry, such as a washing machine or a washer-dryer, have a laundry drum. This usually has a hollow cylindrical shell wall.

In addition, a laundry drum usually also has a base plate at the back. This means that the casing wall in the hollow cylinder shape is closed at the back. At the front, the laundry drum usually has what is known as a front base. The front base and the base plate are usually separate parts from the casing wall that are connected to the casing wall. In this context, it is known that folded connections are created between the components mentioned.

In order to provide an appropriate storage volume for laundry items, it is also known that the jacket wall has bulges oriented radially outwards. For example, EP 1 872 881 A2 A drum shell is known in which an embossed structure with a large number of individual embossed elements is created. However, the embossed elements there are designed to be spaced apart from one another, so that the number of embossed elements is limited. There, the already cylindrically bent drum shell is held in a fixed position during the embossing process.

In addition, it is also known that such a shell wall has a radially expanded area. This is located radially further outward than an end edge strip of the drum shell than this edge strip. This is known, for example, from WO 2011/064201 A1 known. A large number of holes are formed in the radially expanded area of the drum shell.

In addition, the KR 10 2020 0105071 A a laundry drum with a drum shell is known. Larger, radially outward-facing embossed areas are formed in the drum shell. A large number of holes are formed in each of these embossed areas.

Furthermore, IT MC20 090 241 A1 which shows a manufacturing process for a laundry drum from the prior art, from which the present invention is based.

When manufacturing a laundry drum, a variety of process steps are required. These can lead to a wide range of tolerances regarding the orientation and geometry of the drum shell. In this regard, tolerances in the material properties of the raw material can occur. Shape and dimension deviations of the raw blank can occur after cutting from a roll of material. In addition, it is possible that a butt edge offset can occur when welding the end edges of the shell wall. It is also possible that material retraction can occur when the shell wall is formed or expanded. For example, when the required material area for the shell wall is cut from an endless roll, no straight cutting edge occurs. For example, a certain amount of cambering can occur here, resulting in a kind of saber-shaped end edge of this raw material.

It is also possible that if a so-called expansion area is created in a jacket wall of such a washing drum, the roundness of this hollow cylinder shape is no longer present. For example, a certain oval or polygonal shape can then occur here. Especially when such an expansion area is created, it is also possible that a height of a radially smaller edge strip viewed in the direction of the longitudinal axis of the hollow cylinder deviates in the direction of rotation around the longitudinal axis in such a way that a certain tolerance level is exceeded. This can then have disadvantages if this edge strip, as already explained above, is subsequently connected to a front end or a base plate, in particular by means of a seam connection. In total, this can result in tolerance deviations of one millimetre, for example. or greater. However, such deviations, especially in total, are undesirable.

In the case of casing walls for a laundry drum, where the embossed structure is created with a large number of embossed elements that are close together but spaced apart from one another, a problem can also arise when creating flood holes in this casing wall. Due to tolerances, in particular those already mentioned above, the exact positioning of the flood holes has so far only been possible with relatively little precision, especially with these embossed elements. Only if there is a relatively wide-meshed embossed structure can the flood holes be positioned accordingly. If the embossed elements are made closer together, relatively large deviations in the position of the flood holes can occur. This leads to the flood holes becoming degenerate in their geometry. Furthermore, undesirable burrs can appear on the edges of the flood holes that are cut with a cutting tool.

It is an object of the present invention to provide a method, a casing wall and a laundry drum with which or in which the geometric design of an edge strip of a casing wall of a drum is improved.

This object is achieved by a method, a casing wall and a laundry drum according to the independent claims. In particular, the object is also achieved by a household appliance for caring for laundry items with such a laundry drum.

• Bereitstellen einer metallischen Platte;
• Formen der metallischen Platte zu einem Hohlzylinder;
• Erzeugen eines radial nach außen gebauchten Expansionsbereichs in dem Hohlzylinder, wobei der Expansionsbereich vollständig umlaufend um eine Längsachse des Hohlzylinders erzeugt wird, und ein um die Längsachse umlaufender Rand des Expansionsbereichs beabstandet zu einem Hohlzylinderrand des Hohlzylinders erzeugt wird, so dass zwischen dem Rand des Expansionsbereichs und dem Hohlzylinderrand ein ringförmiger Randstreifen des Hohlzylinders gebildet wird;

• Erzeugen zumindest einer Prägestruktur mit einer Vielzahl von Prägeelementen in dem Expansionsbereich;
• Erzeugen zumindest einer Kompensationsprägung in dem Randstreifen und/oder in einem Konusabschnitt des Expansionsbereichs zur lokalen Anpassung der in axialer Richtung bemessenen Höhe des Randstreifens.

One aspect of the invention relates to a method for producing a casing wall for a laundry drum for a household appliance for the care of laundry items, comprising the following steps:

• Providing a metallic plate;
• Forming the metallic plate into a hollow cylinder;
• Creating a radially outwardly bulging expansion region in the hollow cylinder, wherein the expansion region is created completely circumferentially around a longitudinal axis of the hollow cylinder, and an edge of the expansion region circumferentially around the longitudinal axis is created at a distance from a hollow cylinder edge of the hollow cylinder so that an annular edge strip of the hollow cylinder is formed between the edge of the expansion region and the hollow cylinder edge;

• Creating at least one embossed structure with a plurality of embossed elements in the expansion region;
• Creating at least one compensation embossing in the edge strip and/or in a cone section of the expansion region for local adjustment of the height of the edge strip measured in the axial direction.

Using such a method, it is thus possible to produce a casing wall and a laundry drum with a more precise geometry of the edge strip. This means that, in particular, the axial dimension of the edge strip in the direction of rotation around the longitudinal axis of the hollow cylinder is more uniform. In particular, deviations in this axial height can be significantly reduced. In particular, it is possible to minimize axial dimension deviations of this edge strip in the direction of rotation around the longitudinal axis to a value of less than or equal to +/- 0.4 mm, in particular to a value of less than or equal to +/- 0.3 mm. This is a significant advantage in that it improves the geometric accuracy during the manufacturing process. This also results in improved conditions for the subsequent connection of this edge strip to a front base or to a base plate. In particular, a folded connection becomes correspondingly more precise and mechanically more stable.

It is particularly critical when such a casing wall or such a drum casing for a laundry drum is to be produced with both an expansion area and a close-meshed embossed structure that the above-mentioned tolerances can occur. This means that the edge strip can have significant deviations in its axial height. Particularly with a close-meshed embossed structure with an expansion area that is also completely and uninterruptedly formed in the circumferential direction around the longitudinal axis, such larger axial dimension deviations can arise for an edge strip. The invention compensates for this in a particularly advantageous manner. Such a compensation embossing in the edge strip and/or in a conical section of the expansion area thus produces a locally very defined adjustment of the height of the edge strip measured in the axial direction.

Since it is known very precisely during the manufacturing process where such undesirable deviations in the axial extent of the edge strip can occur, local compensation embossing can also be counteracted in a very targeted manner. With the invention, it is therefore possible for the compensation embossing to be produced directly in the edge strip itself. This can therefore lie completely within the edge strip. In addition to this or instead of this, it is also possible for at least one such compensation embossing to be formed adjacent to the edge strip. This is in a conical section of the expansion region. In a cross-sectional view, the expansion region has this conical region or conical section. This borders directly on the edge strip and represents the radial bulge starting from the edge strip. An essentially axial section of the expansion region is then formed adjacent to this conical section. In cross-section, this region therefore runs essentially parallel to the longitudinal axis of the hollow cylinder.

A compensation embossing is an embossing that is intended to be produced in order to carry out an axial adjustment of the height of the edge strip. A compensation embossing is therefore also intended to be produced in such a way that this desired adjustment of the axial height of the edge strip occurs.

In one embodiment, the compensation embossing is only formed in sections in the circumferential direction around the longitudinal axis of the hollow cylinder. The compensation embossing is therefore not formed completely closed all the way around.

In one embodiment, the embossed structure is created as a coherent, embossed zone only partially encircling the longitudinal axis of the hollow cylinder. In the direction of rotation around this longitudinal axis of the hollow cylinder, an azimuth zone is formed adjacent to this embossed zone. The azimuth zone is different from the embossed zone. In particular, this relates to the azimuthal width. In addition to or instead of this, this can also affect the functionality of the two zones. In particular, the azimuth zone is intended to position or form a driver of the laundry drum on it. In particular, the embossed zone is not intended to have a driver arranged or formed on it. In contrast to the expansion region, which is designed to completely encircle the longitudinal axis in the direction of rotation, in particular without interruption. is formed completely circumferentially, this does not apply to the embossed zone. The embossed zone is, however, arranged in the expansion area or is produced therein. In particular, the embossed elements of the embossed structure are only produced in this expansion area. The embossed elements of the embossed structure are different embossed elements from the at least one compensation embossing. This applies in particular both functionally and/or geometrically and/or to the local position.

In an advantageous embodiment, the method first involves cutting off a material region that forms the size of the casing wall from an endless roll. In the proposed method, this plate is then formed into a hollow cylinder before the expansion region is created and before the embossed structure is created, and in particular before flood holes are created. The end edges of this casing wall that face each other are then connected. In particular, they are welded in this respect. The outwardly bulging expansion region is then created in the hollow cylinder. Following this, the embossed structure is then created in this expansion region. It can be provided that at least one compensation embossing is created at the same time as the embossed structure is created. In particular, the compensation embossing is created subsequently to the creation of the embossed structure. In particular, the complete embossed structure is created first and then the at least one compensation embossing is created.

In one embodiment, the at least one compensation embossing is generated at least in part at the azimuth point at which the azimuth zone is formed, viewed in the direction of rotation around the longitudinal axis of the hollow cylinder. Due to the fact that the embossed structure, in particular in its close-meshed design, is not formed completely around the longitudinal axis in one embodiment, but rather the at least one azimuth zone is also formed in this regard, locally different axial heights of the edge strip can arise precisely due to this situation. In particular, in the area of the azimuth zone, an axially different height of the edge strip can occur than in the area in which the embossed structure is generated in the expansion area. In order to be able to adapt this axial height of the edge strip precisely at this azimuth point, the at least one compensation embossing is generated there. In particular, the at least one compensation embossing is generated over its entire azimuthal length completely within the azimuthal width of the azimuthal zone.

In one embodiment, at least one driver of the laundry drum is formed in the azimuth zone of the expansion region. In one embodiment, it is provided that the driver is a separate component to the casing wall. For example, a fastening structure for this separate driver can be formed in the azimuth zone. This fastening structure can, for example, have fastening holes in the azimuth zone. The driver can then be fastened to these.

In one embodiment, the compensation embossing is created around the longitudinal axis of the hollow cylinder as a partially circumferential groove. It is thus designed in particular as a ring section around the longitudinal axis. This creates a relatively delicate structure on the one hand, but it enables the local height adjustment of the edge strip particularly advantageously and precisely. The compensation embossing can extend in the azimuthal direction by at least 50 percent, in particular at least 60 percent, in particular at least 70 percent, in particular at least 80 percent of the azimuthal width of the azimuthal zone.

The compensation embossing can be formed in the edge strip as a radially outwardly bulging embossing.

In one embodiment, after the expansion region has been created, at least several, in particular at least three, centering receptacles are created in the expansion region. The centering receptacles are designed to set a reference position of the hollow cylinder in a horizontal plane at least for the subsequent creation of the embossed structure. In particular, after the expansion region has been created, the hollow cylinder can then be aligned or brought into this horizontal reference position by engaging elements in the centering receptacles before the embossed structure is created. This enables the embossed structure to be created particularly advantageously and with horizontal accuracy. It can thus be created in a particularly advantageous manner with corresponding horizontal accuracy in the direction of rotation around the longitudinal axis.

In one embodiment, the hollow cylinder is moved from its position in which it is arranged in a production plant for producing the expansion area, raised, in particular in the direction of its longitudinal axis. These centering recesses are created in this raised position. This is advantageous because one edge of the hollow cylinder may not be completely flat. If the hollow cylinder is placed on a support under these conditions, a certain inclination to the vertical axis can occur. If the embossed structure is then created in a hollow cylinder positioned in this way, it is also not created axially exactly around the longitudinal axis. This disadvantage is counteracted by this lifting and positioning in the reference position. The hollow cylinder then no longer sits in this reference position on support elements of the production system with the corresponding lower edge of the hollow cylinder.

In one embodiment, after the expansion region has been created and before the embossed structure has been created in the expansion region, the edge strip is locally prestressed azimuthally to the final diameter in an azimuth section. In particular, this prestressing only takes place locally in an azimuth section. The final azimuthal length can then be easily achieved using this procedure. In particular, this can then be achieved with regard to the circular shape of the edge strip around the longitudinal axis at the same time as the embossed structure is created.

This can also improve the accuracy of the individual geometries of the components regarding the edge strip and the embossed structure.

In one embodiment, the azimuthal prestressing of this azimuth section and the generation of the embossed structure in the expansion region are carried out at least temporarily simultaneously.

It can also be provided that, in one embodiment, this azimuthally prestressed azimuthal section is subsequently bent into its uniformly convexly curved shape. This results in a particularly rotationally symmetrical geometry of the edge strip in the circumferential direction around the longitudinal axis. This corresponding deformation of the azimuthally prestressed azimuthal section can in particular take place simultaneously with the embossing of receptacles for at least one driver in the expansion area.

In one embodiment, a first embossed structure is produced as a continuous, embossed zone only partially encircling the longitudinal axis of the hollow cylinder. In particular, a continuous, embossed zone is produced only partially encircling the longitudinal axis, this being produced as a second embossed structure. The second embossed structure is produced separately and spatially separated from the first embossed structure. In particular, a third embossed structure is produced as a continuous, embossed zone only partially encircling the longitudinal axis. In particular, this third embossed structure is separate from the first and second embossed structures. In this respect, it is also produced spatially spaced from the other two embossed structures. The two embossed structures are each produced in particular exclusively in the expansion region of the casing wall. In one embodiment, an azimuth zone is formed between two consecutive embossed zones viewed in the direction of rotation around the longitudinal axis. Viewed in the direction of rotation around the longitudinal axis, a pattern is thus created comprising an embossed structure, followed by an azimuth zone, followed by an embossed structure, followed by an azimuth zone, followed by an embossed zone and followed by an azimuth zone.

In one embodiment, the three embossed zones are created simultaneously. This ensures that no distortion of the shell wall occurs when such a radial force is applied to the expansion area. This achieves the particularly advantageous maintenance of the symmetrical shape of the shell wall and in particular of the expansion area. The relevant molding tools or molding jaws of the production system are arranged equidistant from one another in the direction of rotation around the longitudinal axis.

In one embodiment, flood holes are subsequently created in the expansion region to create the embossed structure and the expansion region. These flood holes are continuous holes through which the lye in the then finished laundry drum can escape. The flood holes are cut in particular by a cutting tool of the production system.

In one embodiment, the previously single-layer edge strip is connected to a base or a base plate of the laundry drum that is separate from the hollow cylinder. In particular, a folded connection is made between the edge strip and the floor. In addition or instead of this, in one embodiment, a previously single-layer edge strip is connected to a front base of the laundry drum that is separate from the hollow cylinder. Here too, in an advantageous embodiment, a folded connection can be created. The edge strip is designed in a single layer before the folded connection is created.

A further aspect of the invention relates to a casing wall for a laundry drum, obtainable by a method according to the above-mentioned aspect or an advantageous embodiment thereof.

A further aspect of the invention relates to a laundry drum for a household appliance for the care of laundry items. The laundry drum has a hollow cylinder as a casing wall. This casing wall has an expansion region that is perpendicular to the longitudinal axis of the hollow cylinder and thus bulges radially outwards. The expansion region is formed completely around a longitudinal axis of the hollow cylinder. In this respect, it is thus also formed without interruption around this longitudinal axis. In addition, the expansion region has an edge that runs around the longitudinal axis. This is formed at a distance from an end-side hollow cylinder edge of the hollow cylinder. An annular, in particular single-layer, edge strip of the hollow cylinder is formed between the edge of the expansion region and the hollow cylinder edge. At least one embossed structure with a plurality of embossed elements is formed in the expansion region. In particular, the embossed structure is only formed in this expansion region. In addition, the laundry drum has at least one compensation embossing that is separate from the embossed element of the embossed structure. This compensation embossing is formed in the edge strip and/or in a cone section of the expansion area. The compensation embossing is designed for local adjustment of the height of the edge strip measured in the axial direction. This axial direction therefore extends in the direction of the longitudinal axis of the hollow cylinder. This longitudinal axis of the hollow cylinder is also the longitudinal axis of the laundry drum.

The compensation embossing is designed to be functionally and locally different from an embossed element.

Advantageous embodiments of the above-mentioned method, particularly in terms of their result, are also to be regarded as advantageous embodiments of the laundry drum. In this regard, material features are also formed which the laundry drum has.

In one embodiment, the embossed structure is formed with a close mesh. This means that the embossed elements are formed directly adjacent to one another. Thus, for example, a boundary wall of an embossed element is also simultaneously the boundary wall of the further embossed element that adjoins it. In particular, the embossed structure with the embossed elements is formed as a honeycomb pattern or as a honeycomb structure. A shape and thus a boundary wall of an embossed element can be dome-shaped. In this regard, the dome-like curvature or the trough is formed towards the longitudinal axis and thus towards the receiving volume of the laundry drum. A boundary contour of such a curved shape of the embossed element can be drop-shaped. This means that two contour edges are formed, in particular symmetrically to one another. These can each be formed in a wave shape. These two contour lines are connected to one another at the respective wave ends. As a result, the relevant contour shape of the entrance of such an embossed element formed as a trough tapers towards the azimuthal ends. In particular, an embossed element is thus formed tapering at its azimuthally opposite ends of the boundary contour.

In the method for producing the casing wall for a laundry drum, in particular in a first step, after the hollow cylinder has been produced, it is aligned for squareness and roundness. To do this, this casing wall is first placed on edge recordings of a production system. For the radial alignment of the casing wall, an edge cutout of the weld seam, at which the abutting edges of the casing wall are joined, is used as a centering mark. In this regard, the casing is then positively received via a nose of the production system. In a further step, three-part mold jaws of the production system then protrude from the center of the production system into the expansion area, which was previously created, in order to align it centrally and at right angles to the longitudinal axis of the hollow cylinder. In particular, these mold jaws have the shape of the expansion area. The mold jaws therefore lie positively on an inner side of the casing wall in the expansion area.

After the expanded area is positioned centrally and at a right angle on the mold jaw, three new edge cutouts including centering holes or centering mounts are created in a further step. As already explained above, this enables the reference position with regard to the horizontal alignment of the hollow cylinder for subsequent processes.

During the final calibration to the final diameter of the hollow cylinder, as already explained above, in one embodiment an elastic pre-stretching or pre-tensioning of a circumference of the drum shell or the shell wall, in particular in the edge strip, is carried out. In particular, the embossed structure is then created in the expansion area at the same time. This advantageously enables the markings from a previous expansion step in which the expansion area was created to be smoothed out. This achieves a higher surface quality. Furthermore, an increase in dimensional stability is achieved because the pre-tensioning results in less material springback. The different axial heights of the edge strip are at least partially compensated for by the at least one compensation embossing that is then created. This achieves a uniform edge strip for flanging or folding.

In one embodiment, the mold jaws of the production system protrude from the core into the final end position and slightly pre-tension the casing wall around the circumference. This is done in particular in the edge strip. Then, die segments of the production system, which are intended to create the receiving structure for the drivers, also advance. In particular, they fill the entire interior of the casing wall or the hollow cylinder. Then, outer segments of the production system move onto this casing wall and freeze the pre-tensioned area of the hollow cylinder in the final diameter. In particular, this is done by the embossing process for the embossing structure and/or for creating the fastening structure of the driver. The method explained above is very advantageous in this regard, especially since a geometrically precise edge strip is particularly important for the flanging process or the folding process of the casing wall with the front base and/or the base plate. As already explained above, this makes it possible to achieve an axial tolerance of the height of the edge strip of less than or equal to +/- 0.3 mm.

The information "top", "bottom", "front", "back", "horizontal", "vertical", "depth direction", "width direction", "height direction" indicate the positions and orientations given during proper use and proper positioning of the casing wall or the washing drum or the appliance.

Further features of the invention emerge from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and/or shown alone in the figures can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the invention. Thus, embodiments are also to be regarded as encompassed and disclosed by the invention that are not explicitly shown and explained in the figures, but which emerge and can be produced from the explained embodiments through separate combinations of features. Embodiments and combinations of features are also to be regarded as disclosed that therefore do not have all the features of an originally formulated independent claim.

Fig. 1

eine perspektivische Darstellung eines Ausführungsbeispiels einer erfindungsgemäßen Mantelwand für eine Wäschetrommel;

Fig. 2

eine Seitenansicht eines Ausführungsbeispiels einer erfindungsgemäßen Mantelwand für eine Wäschetrommel; und

Fig. 3

eine Frontansicht eines Ausführungsbeispiels eines erfindungsgemäßen Haushaltsgeräts zur Pflege von Wäschestücken mit einem Ausführungsbeispiel einer erfindungsgemäßen Wäschetrommel.

Embodiments of the invention are explained in more detail below using schematic drawings. They show:

Fig.1

a perspective view of an embodiment of a casing wall according to the invention for a laundry drum;

Fig.2

a side view of an embodiment of a jacket wall according to the invention for a laundry drum; and

Fig.3

a front view of an embodiment of a household appliance according to the invention for the care of laundry items with an embodiment of a laundry drum according to the invention.

In the figures, identical or functionally identical elements are provided with the same reference symbols.

In Fig.1 is a schematic and perspective illustration of an embodiment of a casing wall 1 for a laundry drum for a household appliance for the care of laundry items. The drum casing or casing wall 1 has a longitudinal axis A. The casing wall 1 is in particular made in one piece, in particular from metal, in particular stainless steel. The casing wall 1 is designed as a hollow cylinder 2. It has an expansion region 3 that is perpendicular to the longitudinal axis A and thus bulges radially outwards. The expansion region 3 is designed to run completely around the longitudinal axis A without interruption. The expansion region 3 is thus more or less a circumferential bead. In the embodiment, this expansion region 3 is designed at a distance from a first hollow cylinder edge 4 of the casing wall 1. It is also designed at a distance from a second hollow cylinder edge 5. This means that the expansion region 3 ends in these opposite end hollow cylinder walls 4 and 5 in a shortened or set back manner. For this purpose, the expansion region 3 has a first azimuthally circumferential edge 6. Furthermore, the expansion region 3 has a second, azimuthally circumferential edge 7. The two edges 6 and 7 are formed in the circumferential direction around the longitudinal axis A. Viewed in the axial direction, the first edge 6 is formed at a distance from the first hollow cylinder edge 4. The second edge 7 is also formed at a distance from the second hollow cylinder edge 5. As can be seen, an edge strip 8 of the casing wall 1 is formed between the first hollow cylinder edge 4 and the first edge 6. The radius of this edge strip 8 is smaller than that of the expansion region 3. The edge strip 8 is axially limited by this edge 6 and this hollow cylinder edge 4.

In one embodiment, a further edge strip 9 is formed between the second edge 7 and the second hollow cylinder edge 5. This further edge strip 9 has a smaller radius than the expansion region 3. The edge strip 9 is axially limited by the edge 7 and the hollow cylinder edge 5.

The edge strip 8 is here, or at this point in time when the entire washing drum was manufactured, still formed as a single layer. The edge strip 9 is here still formed as a single layer.

The expansion area 3 has a conical section 10. The conical section 10 ends directly at the first edge 6. It extends from this first edge 6 to outside in a conical shape in order to merge into a hollow cylindrical section 11 of the expansion region 3. Accordingly, a further conical region 12 is also formed on the axially opposite side. This ends at the second edge 7 on the one hand and at the hollow cylindrical section 11 on the other.

The edge strip 8 is ring-shaped. The edge strip 9 is ring-shaped.

In addition, the casing wall 1 has an embossed structure 13. In the exemplary embodiment, a further embossed structure 14 is also formed. In addition, the casing wall 1 in the exemplary embodiment is provided with a third, here in Fig.1 not recognizable embossed structure. The three embossed structures 13, 14 shown here as examples are separate embossed structures. They are formed equidistant from one another in the direction of rotation around the longitudinal axis A in the expansion region 3, in particular the hollow cylindrical section 11 of the expansion region 3. As can also be seen, a different azimuth zone 20 is formed between the embossed structures 13 and 14. As a result, the two adjacent embossed structures 13 and 14 are spaced from one another in the direction of rotation around the longitudinal axis A. The azimuth zone 20 is provided in particular so that a driver of a laundry drum can be positioned on it. In addition, there is also a gap between the embossed structure 13 and the Fig.1 A further azimuth zone is formed between the embossed structure 14 and the Fig.1 A further azimuth zone is formed in a third, further embossed structure, which cannot be seen. These further azimuth zones are intended so that a further driver can be arranged on the inside of the casing wall 1.

The embossed structure 13 is designed as a continuous, embossed zone. It is only partially produced around the longitudinal axis A. The embossed structure 14 is also designed as a continuous, embossed zone and is partially produced around the longitudinal axis A. Each embossed structure 13, 14 has a large number of embossed elements 15. Some embossed elements 15 are shown here only as examples and indicated. Fig.1 with the reference symbol. In particular, the respective embossed structure 13, 14, as shown in Fig.2 This means in particular that the individual Embossing elements 15 are formed directly adjacent to each other. This also means that a boundary contour of an embossing element is also simultaneously the boundary contour of the adjacent embossing element. As shown in Fig.2 As can be seen, in an advantageous embodiment, an embossed element is drop-shaped when the casing wall 1 is viewed from the side. This means that in such a side view, the limiting contour of such an embossed element 15 is drop-shaped or bulged. With the azimuthally opposite ends, this limiting contour tapers to a point. A limiting contour limits the opening entrance of an embossed element 15 designed as a trough.

As further stated in Fig.1 As can be seen, this casing wall 1 has fastening receptacles 16. These fastening receptacles 16 are intended for fastening a driver. In particular if this is designed as a separate component.

In addition, in the exemplary embodiment, a centering opening is also formed in the azimuth zone 20. Preferably, such a centering opening is formed in each azimuth zone 20. These centering openings or centering receptacles 17 are formed in a horizontal plane. This means that this casing wall 1 can be brought into a horizontal reference position during manufacture after a specific intermediate manufacturing state. This is particularly advantageous in order to subsequently produce the embossed structures 13, 14 during manufacture and to be able to produce and align them exactly horizontally.

The casing wall 1 also has at least one compensation embossing 18. Generally speaking, a compensation embossing is a separate, embossed compensation element. It is formed at a distance from the embossed structures 13, 14 and thus from the embossed elements 15. In one embodiment, the compensation embossing 18 is formed in the edge strip 8. In another embodiment, it can also be formed in the edge strip 9 in addition to or instead of this. In one embodiment, at least one compensation embossing 18 is formed completely in the edge strip 8. The explanation given in this regard and also the following explanation also apply to the edge strip 9 in another embodiment in addition to or instead of this.

In one embodiment, the compensation embossing 18 is intended for the local adjustment of the height h of the edge strip 8 measured in the axial direction and thus in the direction of the longitudinal axis A. This height h is measured between the first edge 6 and the first hollow cylinder edge 4. The compensation embossing 18 is intended and designed to adjust or compensate for this height h. As a result, the height h in the circumferential direction around the longitudinal axis A for the entire edge strip 8 can be formed in such a way that there is a maximum deviation of +/- 0.3 mm.

This can be seen in relation to a reference height.

In one embodiment, the at least one compensation embossing 18 is formed in the circumferential direction around the longitudinal axis A and thus, viewed azimuthally, at the azimuthal point at which the azimuthal zone 20 also extends. In particular, the at least one compensation embossing 18 is formed in its azimuthal length completely within the azimuthal length of this azimuthal zone 20. In one embodiment, it can be provided that the compensation embossing 18 is formed in the cone section 10. This can be completely or at least partially the case.

In one embodiment, the compensation embossing 18 is a groove formed in the circumferential direction around the longitudinal axis A. It represents a ring section. The casing wall 1 designed in this way is part of a laundry drum. This laundry drum can then additionally have a base plate. This base plate is separate from the casing wall 1. It is connected to the casing wall 1. In this regard, a flanging process or a folding process can be provided. This forms a folded connection between the edge strip 9 and the base plate.

In one embodiment, such a laundry drum can have a front base. This is separate from the casing wall 1. The front base can be connected to the casing wall 1 by a flanging process or a folding process. In particular, the edge strip 8 is connected to this front base by a folding connection. This is a direct connection in each case.

In Fig.2 the casing wall 1 is shown in a side view. For the sake of clarity, the embossed structure 14 is not shown here. In addition, Fig.2 , as well as in Fig.1 , the connection point 19 is shown, at which the abutting edges of the base plate of the casing wall 1, which is shaped as a hollow cylinder, are connected to one another, in particular welded to one another. This is formed here in the azimuth zone 20.

To produce the drum wall or the casing wall 1, a base plate of the casing wall 1 is first provided. This plate part is in particular unrolled from an endless roll and cut to length accordingly.

This plate is then rolled up to form a hollow cylinder 2 and connected to one another at the end edges facing each other. In particular, a welded connection is created here. The hollow cylinder 2 thus prepared is then radially expanded in certain areas in a production plant. For this purpose, corresponding expansion elements of the production plant can be introduced into the finished hollow cylinder 2 or the hollow cylinder 2 is set up accordingly so that it surrounds these expansion elements. The expansion elements or mold jaws are then moved radially so that the radially bulged expansion area 3 is formed in the hollow cylinder 2.

In a further manufacturing step, the centering receptacles 17 already explained are then preferably formed.

It can be provided that the fastening receptacles 16 are formed simultaneously or before or after the creation of the centering receptacles 17.

Once the centering seats 17 have been created, the casing wall 1, as it has been manufactured up to that point, is axially raised and brought into a reference position. It no longer rests with an edge on edge seats of the production system, but is raised in this respect. For this purpose, corresponding elements can engage in the centering seat 17 and this desired reference position, which is an exact horizontal alignment of the hollow cylinder manufactured in this way, is then set. In this reference position, the edge strip 8 is then preferably pre-stressed in a further, subsequent production step. and/or the edge strip 9. In particular, an azimuthal stretching of this edge strip 9 and/or 8 is carried out.

In a further manufacturing step, the embossed structures 13, 14 are then produced in the expansion region 3. In particular, these separate embossed structures 13, 14 are produced simultaneously. In one embodiment, the final diameter of the edge strips 8 and/or 9 is also produced at the same time as the respective embossed structure 13, 14 is produced. The prestressed state in this regard is formed into the final convex geometry of the edge strips 8, 9.

In a further, in particular subsequent, manufacturing step, the at least one compensation embossing 18 is produced.

It is possible that a deformation of a centering opening 17 can also occur during embossing. Therefore, in an advantageous embodiment, the centering openings 17 are also created at the same time as the fastening receptacles 16 are produced. As a result, these centering openings 17 can be recalibrated for subsequent processes, in particular positioning the flange or the edge strip 8, 9 for flanging or folding.

In Fig.3 is a schematic representation of a household appliance 30 for washing items of laundry. The household appliance 30 is in particular a washing machine. It has a housing 21. The laundry drum 22, which has the casing wall 1, is arranged in the housing 21. In addition, the laundry drum 22 has a base plate 23 and a front base 24, which is only symbolically indicated here with a reference number. The longitudinal axis A is oriented perpendicular to the plane of the figure. The laundry drum 22 can rotate about this longitudinal axis A. In addition, a door 25 is arranged pivotably on the housing 21. This allows the laundry drum 22 to be closed at the front.

In addition, a tub 26 of the household appliance 30 is also shown in dashed lines. The laundry drum 22 is accommodated in this tub 26. In addition, Fig.3 also to be understood merely symbolically, drivers 27, 28 and 29 are shown, which are arranged on the inside of the casing wall 1. The drivers 27 to 29 are provided for carrying the inserted laundry items when the laundry drum 22 rotates.

Furthermore, it is also provided that the casing wall 1 has a plurality of flood holes. These are continuous holes so that the suds in the washing drum 22 can pass through the flood holes to the outside and into the suds container 26. The flood holes can be created, for example, in the area in which the embossed structures 13, 14 are formed.

List of reference symbols

1

Shell wall

2

Hollow cylinder

3

Expansion area

4

first hollow cylinder edge

5

second hollow cylinder edge

6

first edge

7

second edge

8th

Edge strips

9

Edge strips

10

Cone section

11

hollow cylindrical section

12

Cone area

13

Embossed structure

14

Embossed structure

15

Embossing element

16

Mounting bracket

17

Centering opening

18

Compensation embossing

19

Connection point

20

Azimuth zone

21

Housing

22

Laundry drum

23

Base plate

24

Frontal floor

25

door

26

Lye container

27

Driver

28

Driver

29

Driver

30

Household appliance

H

Height

A

Longitudinal axis

Claims (15)

1. Method for producing a shell wall (1) for a laundry drum (22) for a household appliance (30) for the care of items of laundry, having the following steps:

   - providing a metallic plate;

   - shaping the metallic plate to form a hollow cylinder (2);

   - generating an expansion region (3), bulging radially outward (3), in the hollow cylinder (2), wherein the expansion region (3) is generated completely circulating around a longitudinal axis (A) of the hollow cylinder (2) and an edge (6, 7) of the expansion region (3) circulating around the longitudinal axis (A) is generated at a distance from a hollow cylinder edge (4, 5) of the hollow cylinder (2) so that a ring-shaped edge strip (8, 9) of the hollow cylinder (2) is formed between the edge (6, 7) of the expansion region (3) and the hollow cylinder edge (4);

   characterised by the following steps:

   - generating at least one embossed structure (13, 14) with a plurality of embossing elements (15) in the expansion region (3);

   - generating at least one compensation embossing (18) in the edge strip (8) and/or in a conical segment (10, 12) of the expansion region (3) in order to locally adjust the height (h) of the edge strip (8, 9) measured in the axial direction.
2. Method according to claim 1, wherein the embossed structure (13, 14) is generated as a contiguous, embossed zone only in regions circulating around the longitudinal axis (A) and an azimuth zone (20) is then formed on the embossed zone in the circumferential direction around the longitudinal axis (A) of the hollow cylinder (2).
3. Method according to claim 2, wherein viewed in the circumferential direction around the longitudinal axis (A), the at least one compensation embossing (18) is generated at the azimuth point, at which the azimuth zone (20) is formed.
4. Method according to claim 2 or 3, wherein an agitator (27, 28, 29) is embodied in the azimuth zone (20) of the expansion region (3).
5. Method according to one of the preceding claims, wherein the compensation embossing (18) is generated around the longitudinal axis (A) as an embossed channel which circulates in regions.
6. Method according to one of the preceding claims, wherein, after generating the expansion region (3), at least three centring receptacles (17) are generated in the expansion region, with which a reference position of the hollow cylinder (2) can be adjusted in a horizontal plane at least for the subsequent generation of the embossed structure (13, 14), in particular the hollow cylinder (3) is brought into the reference position by engaging elements in the centring receptacles (17) before generating the embossed structure (13, 14).
7. Method according to claim 6, wherein the hollow cylinder (3) is raised from its position, in which it is arranged in a manufacturing installation for generating the expansion region (3), and in the raised position the centring receptacles (17) are generated.
8. Method according to one of the preceding claims, wherein after generating the expansion region (3) and before generating the embossed structure (13, 14) in the expansion region (3) of the edge strips (8, 9), pretensioning to the final diameter occurs in particular only locally azimuthally on an azimuth segment.
9. Method according to claim 8, wherein the azimuthal pretensioning of the azimuth segment and the generation of the embossed structure (13, 14) in the expansion region (3) is carried out at least occasionally at the same time.
10. Method according to claim 8 or 9, wherein the azimuthally pretensioned azimuth segment is then brought into its uniformly convex curved shape in particular at the same time as embossing the receptacles (16) for at least one agitator (27, 28, 29) in the expansion region (3).
11. Method according to one of the preceding claims, wherein a first embossed structure (13) is generated as a contiguous, embossed zone only in regions circulating around the longitudinal axis (A), a second embossed structure (14) is generated as a contiguous, embossed zone only in regions circulating around the longitudinal axis and a third embossed structure is generated as a contiguous, embossed zone only in regions circulating around the longitudinal axis (A), wherein an azimuth zone (20) is formed in each case between two consecutively embossed zones in each case.
12. Method according to claim 11, wherein the three embossed zones are generated at the same time.
13. Method according to one of the preceding claims, wherein the single-layer edge strip (8, 9) is connected to a base disc (23) of the laundry drum (22) which is separate to the hollow cylinder (2) and/or to a front base (24) which is separate to the hollow cylinder (2), wherein to this end a folded joint is generated and the edge strip (8, 9) is folded at least in regions.
14. Shell wall (1) for a laundry drum (22), obtainable by means of a method according to one of the preceding claims.
15. Laundry drum (22) for a household appliance (30) for the care of items of laundry, having a hollow cylinder (2) as the shell wall (1), which has an expansion region (3), bulging radially outward, in the hollow cylinder (2), wherein the expansion region (3) is embodied completely circulating around a longitudinal axis (A) of the hollow cylinder (2), and an edge (6, 7) of the expansion region (3) circulating around the longitudinal axis (A) is embodied at a distance from a hollow cylinder edge (4, 5) of the hollow cylinder (2) so that a ring-shaped, in particular folded, edge strip (8, 9) of the hollow cylinder (2) is formed between the edge (6, 7) of the expansion region (3) and the hollow cylinder edge (4, 5), wherein at least one embossed structure (13, 14) is embodied with a plurality of embossed elements (15) in the expansion region (3), characterised in that at least one compensation embossing (18) is embodied in the edge strip (8, 9) and/or in a conical segment (10, 12) of the expansion region (3) in order to locally adjust the height (h) of the edge strip (8, 9) measured in the axial direction.

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