DE102021200987A1 - Method for producing a laundry drum with a precise positioning of an embossed structure and flood holes relative to one another, and laundry drum - Google Patents

Abstract

One aspect of the invention relates to a method for producing a laundry drum (29) for a household appliance (27) for the care of laundry items, having the following steps: - providing a metallic plate; - forming the metallic plate into a hollow cylinder (2) so that a casing wall (1) the laundry drum (29) is formed;- producing at least one coherent embossed structure (13, 14) in the casing wall (1), with a large number of embossed elements (15) being produced close-meshed to one another for this purpose;- positionally defined production of flood holes ( 21) on the embossing elements (15).

Description

One aspect of the invention relates to a method for producing a laundry drum for a household appliance for the care of laundry items. A further 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 items of laundry.

Household appliances for the care of items of laundry, such as a washing machine or a washer-dryer, have a laundry drum. This usually has a hollow-cylindrical casing wall.

In addition, a laundry drum usually also has a rear base plate. As a result, the jacket wall is closed to the rear in the hollow cylindrical shape. The front of the laundry drum usually has a so-called end base. The end face and the bottom disk are usually separate parts from the casing wall, which are connected to the casing wall. It is known in this context that folded joints are produced between the components mentioned.

In order to provide a corresponding storage volume for items of laundry, it is also known for the casing wall to have bulges oriented radially outwards. For example, from the EP 1 872 881 A2 a drum shell is known, in which an embossed structure with a multiplicity of individual embossed elements is produced. However, the embossed elements there are designed to be spaced apart from one another, so that the number of embossed elements is limited. There it is provided that the already cylindrically curved 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 large, radially expanded area. Compared to an end edge strip of the drum casing, this is radially further outward than this edge strip. Such is, for example, from the WO 2011/064201 A1 known. A plurality of holes are formed in the radially expanded portion of the drum shell.

In addition, from the KR 10 2020 0105071 A a laundry drum with a drum jacket is known. Larger, radially outwardly projecting embossed areas are formed there in the drum shell. A multiplicity of holes are formed in each of these embossed areas.

In the case of jacket walls for a laundry drum, in which the embossed structure is produced with a multiplicity of embossed elements which are closer together but spaced apart from one another, a problem can also arise when creating flood holes in this jacket wall. Due to tolerances, in particular also those already mentioned above, the exact positioning of the flood holes for these embossed elements has hitherto only been possible relatively imprecisely. Only when there is a relatively wide-meshed embossed structure can the flood holes be formed in a correspondingly positioned manner. If the embossing elements are formed closer to each other, positionally relatively large deviations of the flood holes can occur. This causes the flood holes to become degenerate in their geometry. Such deviations are also visually perceived more easily, since they are recognized in their positional relation to the embossed structure. Furthermore, undesirable burrs can appear on the edges of the flood holes that are cut with a cutting tool. This is particularly the case when flood holes are cut before the embossing forming process.

In conventional methods, it is therefore provided that the flood holes are cut into the still flat plate of the casing wall, from which the hollow cylinder is then subsequently produced, and then the embossed structure is introduced. It is only later that this flat plate is rolled up into a hollow cylinder. In this context, cutting the flood holes before the embossing elements are produced is only possible if the number of embossing elements is very small and they are relatively far apart. Especially when, in a further manufacturing process, the flood holes are first cut into a flat plate, then this plate is formed into a hollow cylinder and the abutting edges are welded accordingly and only then the embossed structure is introduced into the shell wall, undesirable positional values can arise in this regard Deviations between the embossing elements and the flood holes arise.

This can also result in undesirable situations with regard to the removal of the suds from the laundry drum.

Another adverse problem can occur when flood holes are cut in the planar sheet, the sheet is formed into a hollow cylinder, and a radial expansion region is created in the shell wall prior to creating the embossed structure. This can result in structural cracks in the area of the cutting edges of the flood holes. This is also disadvantageous. Furthermore, the flood holes change the roundness in Direction of the material's main flow direction when forming or expanding and become oval. This increases the scope of the potentially angular cutting edge.

It is the object of the present invention to create a method, a casing wall for a laundry drum and such a laundry drum, in which or in which the positional accuracy between embossed elements of an embossed structure and flood holes is improved.

• - Bereitstellen einer metallischen Platte;
• - Formen der metallischen Platte zu einem Hohlzylinder, sodass eine Grundform Mantelwand der Wäschetrommel gebildet wird;
• - Erzeugen zumindest einer zusammenhängenden Prägestruktur in der Mantelwand, wobei dazu eine Vielzahl von Prägeelemente engmaschig zueinander erzeugt werden;
• - Positionell definiertes Erzeugen von Flutlöchern an den Prägeelementen.

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

• - Providing a metallic plate;
• - Forming the metallic plate into a hollow cylinder, so that a basic shape of the outer wall of the laundry drum is formed;
• - Generating at least one cohesive embossed structure in the casing wall, with a large number of embossed elements being generated close-meshed to one another for this purpose;
• - Positionally defined creation of flood holes on the embossing elements.

This method makes it possible for the hollow cylinder to be formed first and thus for a basic geometry of the casing wall of the laundry drum to be formed. Only after this production of the hollow cylinder are both the embossed structure and the flow holes produced in the hollow cylinder. Especially with a close-meshed design of the embossed elements in this respect, the positional accuracy between these embossed elements and the flood holes can be significantly improved by this procedure. Undesirable deformations of the flood holes on the one hand and off-centre production of embossed elements and flood holes on the other hand, as is the case with conventional methods, can be avoided in this way. A very precise production of flood holes on the one hand and embossing elements arranged closely to one another on the other hand is thereby made possible. In particular when, as explained in the production method, these flood holes are to be produced on the embossing element itself and this is closely meshed, the proposed method can significantly improve the positional accuracy. In particular, this also makes it possible to avoid distorted geometries of the flood holes, as is the case when the hollow cylindrical shape is subsequently produced after the flood holes are formed in a flat plate, as is the case in the prior art. Likewise, tearing out of the created flood holes can be avoided in this context. A close-meshed production of the embossed elements means, in particular, that the embossed elements directly adjoin one another. A partial area of a delimiting contour of an embossed element is at the same time also a partial area of a delimiting contour of the adjacent further embossed element. This is the case with several embossing elements, so that this defines the close mesh.

In one exemplary embodiment, the potentially defined creation of flood holes and embossing elements takes place in such a way that the flood holes are created at reference points of the embossing elements. These previously known and desired reference points therefore represent the reference point at which at least one flood hole is to be created.

A positionally defined production therefore also means that there is a predetermined connection between the embossing element part or the reference point and the flooding hole.

In one embodiment, at least some embossing elements are created directly adjacent to each other. A boundary contour of an embossed element is at the same time a boundary contour of the other embossed element. At least one flood hole is created at this boundary contour. It is created in the area of the boundary contour. This is another advantageous embodiment. Because the close-meshed embossed structure also creates a channel system on the inside of the hollow cylinder for draining the suds in the laundry drum. This is therefore also closely meshed and is formed by the correspondingly shaped embossed elements that directly adjoin one another. Very defined drainage channels can thus also be formed as a result. Since the flood holes are then formed precisely on these respective boundary contours, the suds in these drainage channels formed by the boundary contours can be guided directly and purposefully to the flood holes. This improves the drainage of the lye.

In addition, such a close-meshed embossed structure achieves an improved concept for guiding the laundry in the laundry drum. This enables the items of laundry to be stored in the laundry drum with as little contact as possible.

In one embodiment, a boundary contour, which bounds and separates two adjacent embossing elements, is produced with a free edge. The free edge is thus the end of the boundary contour. This free edge is thus also Connecting edge between the two adjacent embossed elements. In particular, boundary contours of adjacent embossed elements now open directly and jointly into this one edge. At least one flood hole is created in this marginal edge. In particular, the flood hole is formed entirely within the area of the marginal edge.

This is a very exposed position of a flood hole, especially in connection with the close-meshed structure of the embossing elements. This further improves the advantages mentioned above.

Precisely the previous production of the hollow cylinder, so that the basic geometry of the casing wall exists, enables the flood holes to be produced in a very precise manner at these very exposed points, namely at these marginal edges, when the embossing elements are then arranged very closely in this respect.

In one embodiment, an embossing element is embossed as a dome-like or bump-like element. The curvature in this regard is directed towards the longitudinal axis of the laundry drum. A quasi-concave shape of the curved wall of an embossing element is thus formed. The boundary wall of the embossing element is thus shaped like a dome. An embossing element entrance, which forms the entrance to the hollow area of the embossing element, is thus on the outside of the casing wall. This entrance is limited by a boundary contour. The boundary contour is the edge of the boundary wall. This boundary contour is formed in particular by the edge. Thus, as it were, a partial area of this delimiting contour of an embossed element protrudes into a partial area of the delimiting contour of the further embossed element directly adjacent thereto. This transition of the boundary contours is then also the edge. The edge thus also represents a relatively narrow web of such a delimiting contour of embossing elements. The edge is thus a narrow, coherent surface strip.

Such an edge is thus also a line element or a thin strip element.

The embossing element is designed in particular as a trough. It is open to the outside, particularly through the entrance.

In one embodiment, a boundary contour of an embossing element can be designed in the shape of a drop. The relevant geometry thus widens on both sides, starting from one end, and then approaches one another again, running towards the other end.

In particular, the embossed structure with the embossed elements is produced as a honeycomb pattern or honeycomb structure. This means that the embossed elements are arranged offset relative to one another in a honeycomb manner.

In one exemplary embodiment, an embossed element is produced with a first end, viewed in the circumferential direction about a longitudinal axis of the hollow cylinder. A first delimitation contour node or boundary edge node is formed from this first end. In particular, several delimiting contours or several partial areas of delimiting contours of embossing elements end at this. At least one flood hole, in particular only two flood holes, is produced at this first boundary contour node, in particular the first boundary edge node. In addition to or instead of this, a second end of the embossing element is produced offset in azimuth. A second boundary contour node, in particular a second edge node, is formed at this second end. In particular, several delimiting contours end at this second node, in particular several partial sections of the delimiting contour of several adjacent embossing elements. At least one flood hole is produced at this second boundary contour node, in particular the second edge node. In particular, exactly two flood holes are created there.

A boundary contour is formed by, in particular, wavy contour sections. These are individual sections of the contour.

Due to the geometry of the embossing elements mentioned above, in particular the shape of the boundary contour at the entrance to the embossing element, specific drainage channels and corresponding courses of the drainage channels are formed on the opposite side, namely the inside of the casing wall. Since these drainage channels then also meet or run into one another at these first and second ends, the creation of at least one flood hole at the corresponding node is particularly advantageous. In particular with regard to the suds guidance on the one hand and the drainage of the suds out of the laundry drum via the flood holes on the other hand.

The method explained above makes it particularly advantageous to be able to precisely position and produce flood holes even at these very exposed points of the embossing elements.

In one exemplary embodiment, an embossed element, in particular all embossed elements, is produced as a dome curved inwards towards the longitudinal axis of the hollow cylinder. Its boundary surface or boundary wall is bulbous and the boundary edge or boundary contour is produced tapering to a point at the azimuthally opposite ends. This is already the advantageous geometry of the embossing elements, as explained above.

In one exemplary embodiment, the multiplicity of embossing elements designed in this way is produced as a honeycomb structure in the casing wall. In particular, an axially oriented first row of embossing elements is produced in the azimuthal direction in the same azimuthal position. This first row is produced to form a second row of likewise axially oriented embossed elements, which are also produced in the same azimuth position, overlapping in the azimuthal direction by half an embossed element with the embossed elements of the first row. In the axial direction, these embossed elements of the second row are produced so that they overlap by half an embossed element with the embossed elements of the first row. In particular, this results in the advantageous honeycomb structure. A very densely packed and particularly close-meshed arrangement of the embossing elements is thereby achieved. In the series process, preferably three embossing fields or embossing structures are produced simultaneously. It would also be possible to produce these embossed fields one after the other.

In one embodiment, flood holes in the boundary edges and embossing elements of a respective row are simultaneously created by a flood hole creation unit. This makes it possible to achieve a particularly high level of symmetry and the rapid generation of flood holes.

In one embodiment, flood holes are simultaneously created at the azimuthally opposite ends of the bounding edges of the embossing elements of a respective row. This also allows the flood holes to be formed in a particularly precise position at both ends of the respective embossed elements in a row. A particularly straight axial line of the respective flood holes at the ends is thereby made possible.

In one embodiment, after the creation of the flood holes in a row of embossing elements, which is created in a first axial position, the hollow cylinder is displaced axially by a stroke corresponding to half the axial height of an embossing element. Subsequently, the flood holes are then produced simultaneously at the opposite ends of the boundary edges of the embossing elements of a row, this row being the one that is offset axially by half an embossing element to the already perforated rows. This also makes it possible to create several flood holes simultaneously, quickly and yet very precisely in position. In particular of flood holes in a relative axial row of embossing elements.

In one embodiment, three separate, close-meshed embossed structures are produced on the casing wall. These are arranged or created equidistantly from one another in the direction of rotation about the longitudinal axis of the hollow cylinder.

Drivers are formed in the intermediate areas of the casing wall between the embossed structures.

In one embodiment, after the hollow cylinder has been produced, an expansion embossing is produced in the casing wall. This defined expansion embossing forms an expansion area that bulges radially outward. This expansion area is created as a circumferential and outwardly curved annular bead. It is designed to run all the way around the longitudinal axis. In this regard, it is therefore also designed without interruption around the longitudinal axis. The at least one separate embossed structure with the plurality of embossed elements is produced in this expansion embossing or in this expansion area, which is very large compared to an embossed element of the embossed structure. The embossing elements are generally of the same shape and size in one embodiment.

In one embodiment, a bottom wall or a bottom disk is attached to the hollow cylinder. The base wall is a component of the laundry drum that is separate from the casing wall. The laundry drum is closed at one axial end of the hollow cylinder by the bottom wall.

In one embodiment, an end cap is attached to the hollow cylinder. The end cap is a separate component from the hollow cylinder. In particular, the connection between the end face and the hollow cylinder is formed by a flanging process and thus by a rabbeted connection. The same can also be provided between the hollow cylinder and the bottom disk.

In one embodiment, the flood holes are created as circular holes.

In the method, in an advantageous exemplary embodiment, as has already been explained above, sequential generation of several flood holes. In particular, there is a sequential cutting of flood holes in the hollow cylinder of the casing wall. It can be provided that more than 50, in particular more than 100, in particular more than 200 and in particular more than 250 flood holes are produced per embossed structure. If a casing wall then has, for example, two separate embossed structures or three separate embossed structures, then each of these embossed structures also has this number of flood holes. Provision can be made for the flood holes to be produced simultaneously in their individual segments. These flood holes can be cut from the inside out. They can be cut sequentially in a time interval of less than 25 s, in particular between 50 and 20 s. In one exemplary embodiment, a cutting unit of the production plant consists of 20 cutting punches, for example. This allows 20 flood holes to be cut simultaneously. This can thus be done accordingly for each embossed structure. The cutting unit can thus simultaneously cut two vertical rows of holes, in particular of 10 flood holes each, per cutting process. This has already been explained above.

In a further procedure, the jacket wall can then be rotated further after each cutting cut, for example clockwise by a specific number, in order then to cut the next row of flood holes. If, for example, an embossed structure has embossed elements that are connected and therefore close-meshed to one another, the jacket wall can be rotated seven times by a further corresponding division after each cutting process, in which in particular two parallel rows each with 10 flood holes are cut, so that an exemplary number of axial rows with an odd number of an embossing structure is cut.

In particular, after cutting the eighth row of flood holes, the shell wall is excavated by one pitch in the vertical direction. The pitch here is also half the size of an embossed element. Here this then relates to half of an axial height of an embossing element. In this respect, the same sequence is then carried out counterclockwise with regard to the cutting of all flood holes in these rows of the embossing structure and the cutting unit is operated accordingly.

The method thus enables exact positioning of the flood holes on the narrow webs of the close-meshed embossed structure. In particular, the marginal edges already explained above, which are formed as a continuous narrow surface or narrow surface strips, are produced by these narrow webs

It is also possible to create very dimensionally stable, particularly round, flood holes. The flood holes can be formed with a significantly reduced burr, since these are no longer introduced before the forming process and thus before the production of the hollow cylinder and consequently can no longer be deformed and structurally torn open by this hollow cylinder forming. In addition, lower cutting forces and thus more cost-effective system technologies come to the fore.

A further aspect of the invention relates to a jacket wall, in particular a laundry drum for a household appliance for the care of laundry items. The casing wall, in particular the laundry drum, can be obtained in particular by a method according to the aspect mentioned above or an advantageous exemplary embodiment thereof.

In one exemplary embodiment, the laundry drum has a close-meshed embossed structure. This means that the embossed structure has a large number of individual embossed elements that directly adjoin one another. In particular, in this context, the boundary contours of an entry of such a curved configuration of an embossing element merge into one another. Free edges of this delimiting contour open into a linear edge or an edge strip, in which a free edge of an adjacent delimiting contour of a further embossing element also ends.

Flood holes of this laundry drum are formed on these marginal edges. In particular, they are formed entirely within these marginal edges. In particular, they are arranged at azimuthally opposite ends of the delimiting contour of an embossing element. This enables the flood holes to be positioned precisely at these specific positions of embossing elements. A stable position of the flood holes to the embossing structure is made possible. A dimensionally stable design of the flood holes has been achieved. They are circular. Oval flood holes can be avoided. The cutting edges of the flood holes are formed without surface cracks. Burr formation is also reduced or avoided. The course and design of the cutting edge is smoother or brighter up to the breaking edge.

The information “top”, “bottom”, “front”, “back”, “horizontal”, “vertical”, “depth direction”, “width direction”, “height direction” are the intended use and intended positioning of the jacket wall or the laundry drum or the device given positions and orientations.

Further features of the invention result from the claims, the figures and the description of the figures. The features and feature combinations mentioned above in the description, as well as the features and feature combinations 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 the frame to abandon the invention. The invention is therefore also to be considered to include and disclose embodiments that are not explicitly shown and explained in the figures, but that result from the explained embodiments and can be generated by separate combinations of features. Versions and combinations of features are also to be regarded as disclosed which therefore do not have all the features of an originally formulated independent claim.

• 1 eine perspektivische Darstellung eines Ausführungsbeispiels einer erfindungsgemäßen Mantelwand für eine Wäschetrommel;
• 2 eine Seitenansicht eines Ausführungsbeispiels einer erfindungsgemäßen Mantelwand für eine Wäschetrommel; und
• 3 eine Frontansicht eines Ausführungsbeispiels eines erfindungsgemäßen Haushaltsgeräts zur Pflege von Wäschestücken mit einem Ausführungsbeispiel einer erfindungsgemäßen Wäschetrommel.

Exemplary embodiments of the invention are explained in more detail below with the aid of schematic drawings. Show it:

• 1 a perspective view of an embodiment of a casing wall according to the invention for a laundry drum;
• 2 a side view of an embodiment of a jacket wall according to the invention for a laundry drum; and
• 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 1 an embodiment of a casing wall 1 for a laundry drum for a household appliance for the care of laundry items is shown in a schematic and perspective representation. The drum shell or the shell wall 1 has a longitudinal axis A. The jacket wall 1 is in particular formed in one piece, in particular made of metal, in particular high-grade steel. The shell 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 outward. The expansion area 3 is designed to run completely around the longitudinal axis A without any interruptions. The expansion area 3 is thus virtually a peripheral bead. In the exemplary embodiment, this expansion area 3 is formed at a distance from a first hollow cylinder edge 4 of the jacket wall 1 . In particular, it is also formed at a distance from a second edge 5 of the hollow cylinder. This means that the expansion area 3 ends shortened or set back in these opposite end-side hollow cylinder walls 4 and 5 . For this purpose, the expansion area 3 has a first edge 6 running around in the azimuth. Furthermore, the expansion area 3 has a second, azimuthal peripheral edge 7 . The two edges 6 and 7 are formed around the longitudinal axis A in the circumferential direction. Viewed in the axial direction, the first edge 6 is formed at a distance from the first edge 4 of the hollow cylinder. Likewise, the second edge 7 is formed at a distance from the second edge 5 of the hollow cylinder. As can be seen, an edge strip 8 of the jacket wall 1 is formed between the first edge 4 of the hollow cylinder and the first edge 6 . The radius of this edge strip 8 is smaller than that of the expansion area 3. The edge strip 8 is limited axially by this edge 6 and this edge 4 of the hollow cylinder.

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

The edge strip 8 is still formed in one layer here or at this point in time when the entire laundry drum is being manufactured. The edge strip 9 is still single-layered here.

The expansion area 3 has a cone section 10 . The cone section 10 ends directly at the first edge 6 . Starting from this first edge 6 , it transitions outwards in a cone shape in order to transition into a hollow-cylindrical section 11 of the expansion region 3 . Correspondingly, a further conical area 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 hand.

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 connected to a third, here in 1 provided with an unrecognizable embossed structure. The three embossed structures 13, 14 shown here by way of example are separate embossed structures. They are equidistant from one another in the direction of rotation around the longitudinal axis A in the expansion area 3 , in particular the hollow-cylindrical section 11 of the expansion area 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 apart from one another about the longitudinal axis A in the circumferential direction. The azimuth zone is 20 provided in particular that a driver of a laundry drum is positioned on it. In addition, between the embossed structure 13 and the in 1 not recognizable further embossed structure formed another azimuth zone. Likewise, between the embossed structure 14 and the in 1 not recognizable, third, further embossed structure formed a further azimuth zone. These further azimuth zones are intended to be provided so that a further driver can be arranged on the inside of the shell wall 1 .

The embossed structure 13 is designed as a continuous, embossed zone. It is only partially generated around the longitudinal axis A. Likewise, the embossed structure 14 is designed as a cohesive, embossed zone and is thereby produced circumferentially around the longitudinal axis A in some areas. Each embossed structure 13, 14 has a multiplicity of embossed elements 15. Some embossed elements 15 in 1 provided with the reference number. In particular, the respective embossed structure 13, 14, as shown in 2 can be seen better, designed as a honeycomb structure. This also means, in particular, that the individual embossed elements 15 are formed directly adjacent to one another. This also means that a delimiting contour of an embossed element is also at the same time a delimiting contour of the adjacent embossed element. How to in 2 As can be seen, in an advantageous exemplary embodiment, an embossed element is designed in the form of a drop when the jacket wall 1 is viewed from the side. This means that with such a side view, the boundary contour of such an embossing element 15 is designed in the form of a drop or bulge. With the azimuthally opposite ends, this boundary contour tapers to a point. A delimiting contour delimits the opening entrance of an embossing element 15 designed as a depression.

As moreover in 1 as can be seen, this casing wall 1 has fastening receptacles 16 . This mounting receptacles 16 are provided for attaching a driver. In particular if this is designed as a separate component.

In addition, a centering opening is also formed in the azimuth zone 20 in the exemplary embodiment. Such a centering opening is preferably formed in each azimuth zone 20 . These centering openings or centering receptacles 17 are formed in a horizontal plane. In this way, this casing wall 1 can be brought into a horizontal reference position during production according to a specific intermediate production state. In particular, this is advantageous in order to be able to subsequently produce the embossed structures 13, 14 during production and to be able to produce and align them exactly horizontally.

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

In one embodiment, the compensation embossing 18 is intended for 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 provided and designed to adjust or compensate for this height h. As a result, the height h in the circumferential direction about the longitudinal axis A can be formed for the entire edge strip 8 in such a way that there is a maximum deviation of +/-0.3 mm.

This can be seen relative to a reference altitude.

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

In one exemplary embodiment, the compensating embossing 18 is a groove formed around the longitudinal axis A in the circumferential direction. 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 bottom disk. This floor disk is separate from casing wall 1. It is connected to the casing wall 1. In this regard, a flanging process or a folding process can be provided. As a result, a fold connection is formed between the edge strip 9 and the bottom pane.

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

In 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, in 2 , as well as in 1 , the connection point 19 is shown, at which the abutting edges of the base plate, which is shaped as a hollow cylinder, of the jacket wall 1 are connected to one another, in particular welded to one another. This is formed in the azimuth zone 20 here.

To produce the drum wall or the shell wall 1, a base plate of the shell 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 one another. In particular, a welded connection is produced at the connection point 19 here. The hollow cylinder 2 provided in this way is then radially expanded in some 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 in this regard, so that it surrounds these expansion elements. The expansion elements or mold blocks are then moved radially, so that the radially bulged expansion area 3 is formed in the hollow cylinder 2 .

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

Provision can be made for the fastening receptacles 16 to be formed at the same time or before or after the centering receptacles 17 are produced.

Once the centering receptacles 17 have been produced, the casing wall 1, as it has been produced up to that point, is raised axially and brought into a reference position. It is therefore no longer seated with a rim or an edge on edge recordings of the production plant, but is raised in this regard. For this purpose, corresponding elements can engage in the centering receptacle 17 and this desired reference position, which is an exact horizontal alignment of the hollow cylinder produced in this regard, is then set. In this reference position, a prestressing of the edge strip 8 and/or the edge strip 9 is then preferably carried out in a further, subsequent production step. In particular, an azimuthal stretching of this edge strip 9 and/or 8 is carried out in this regard.

A deformation of a centering opening 17 may also occur during embossing. Therefore, in an advantageous exemplary embodiment, the centering openings 17 are also produced 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 edge strip 8, 9 for flanging or folding.

In a further manufacturing step, the embossed structures 13, 14 are then produced in the expansion area 3. In particular, these separate embossed structures 13, 14 are produced simultaneously. In one exemplary 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 respect is formed into the final convex geometry of the edge strips 8, 9.

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

In addition, in 2 It can also be seen that a large number of flood holes 21 are formed on the jacket wall 1 . The flood holes 21 are generated in a defined position. They are generated on embossing elements 15 in a positionally defined manner. Due to the arrangement of the embossing elements 15, the flood holes 21 are formed in rows and columns.

As in 2 As can be seen, the embossed elements 15 are shaped as domes or humps that bulge inwards, ie towards the longitudinal axis A. in the in 2 shown view from the outside they are thus quasi inwardly bulging depressions. These embossing elements 15 are provided with an entrance 15a on the outside 11a of the area 11 . This entrance 15a is delimited by a delimiting contour. The boundary contour has a first contour section 15b and a second contour section 15c. The two contour sections 15b and 15c each have a wavy shape. In particular, they are formed symmetrically to a horizontal line. In the azimuthal direction, the delimiting contour of an embossing element 15 has a first end 15d and an opposite, further end 15e. In this side view, the entire boundary contour of this input 15a of an embossing element 15 is drop-like. At the opposite ends in the azimuthal direction, this form of the delimiting contour is tapered, in particular tapering in each case to a point.

On this outer side 11a, partial sections of the boundary contours of embossed elements 15 that are directly adjacent to one another and abut each other end in a free edge 22 in each case. In this context, the free edge 22 is a coherent flat strip or a flat edge line. This thus delimits two adjacent embossing elements 15 in each case. The edge 22 is also formed on the respective ends 15b and 15c.

As in 2 can be seen, the flood holes 21 are formed on these edges 22. In particular, they are formed completely in the marginal edges 22 with their entire surface. For the sake of clarity, in 2 only a few flood holes 21 shown as an example.

In one exemplary embodiment, the adjacent ends 15e and 15b of two embossed elements 15 that follow one another in the direction of rotation about the longitudinal axis A are formed at a boundary contour node 23 . A flood hole 21 is created at this boundary contour node 23 . In this regard, further boundary wall nodes are provided in each case. An example is in 2 a further boundary contour node 24 is shown, at which in turn two ends 15e and 15b on two consecutive embossing elements 15 end or are formed. At least one flood hole, in particular exactly two flood holes 21, is also formed on this boundary contour node 24. This is also in an enlarged detail 2 shown as an example for the other areas.

As moreover in 2 as can be seen, a plurality of embossing elements 15, here ten in the exemplary embodiment, are formed in an axial row aligned with one another. In the direction of rotation about the longitudinal axis A, a plurality of embossing elements 15 are also formed in a row one after the other in the same axial position.

As can also be seen, adjacent to this is by way of example in 2 shown first axial row 25, a second row 26 of embossing elements 15 is formed. These embossed elements 15 of the second row 26 are also arranged in series with one another in the axial direction. As can be seen, the second row 26 is offset in the direction of rotation about the longitudinal axis A by half the length of an embossed element 15 relative to the embossed elements 15 of the first row 25 . In the axial direction, there is also an offset of half the axial height of an embossed element between the embossed elements 15 of the first row 25 and the embossed elements 15 of the second row 26 . This then alternates with the further rows of embossed elements 15 in this embossed structure 13. This is also formed correspondingly with the further embossed structures 15 etc. that are advantageously present. The aspects explained for the embossed structure 13 therefore also apply to the other embossed structures of the drum wall or the casing wall 1.

In one embodiment, this results in a flow hole, in particular exactly two flow holes 21, being produced on each boundary contour node 23, 24 of these correspondingly arranged embossing elements 15 of the embossing structure 13.

When producing these rows of flood holes, it can be provided that a corresponding cutting unit of the production plant can produce twenty flood holes 21 at the same time. These may be, for example, those flood holes in an axial row of dies that are formed at the ends 15d and those flood holes that are to be created at the opposite ends 15e of the dies 15 of that specific row. These twenty flood holes can then be cut simultaneously in the second embodiment. However, this is only to be understood as an exemplary embodiment and both the number and the order can be different.

Based on this approach, when these first twenty flood holes 21 have been cut, the jacket wall 1 can be rotated further about the longitudinal axis A in such a way that further flood holes are formed at the ends 15d and 15e of the next row 25, which is formed in the same axial position 21 are generated. This takes place until all rows that are formed in the same axial position have been produced at the respective ends 15d and 15e of the respective embossed elements 15, each with a flood hole 21.

Subsequently, the jacket wall 1 can then be displaced in the axial direction by half the height of an embossing element 15 . Then, in a correspondingly reversed manner, those flood holes 21 can be cut which, in this respect, are axially spaced by half an embossing element 15 offset further rows of the embossed structure 13 are cut.

A pair of flood holes 21 is thus formed at each boundary contour node 23 , 24 . This is because the ends 15d and 15e of adjacent embossed elements 15 that face one another and end in the respective boundary nodes 23 or 24 are each formed with one flood hole 21, in particular only a single one.

In particular, when a plurality of separate embossing structures 13, 14 are formed, the flood holes 21 are simultaneously cut in the respective embossing structures 13, 14. In this regard, three identically designed and identically working cutting units are provided.

For the sake of clarity, 2 only one boundary contour node 23 and one boundary contour node 24 are provided with the corresponding reference symbols. In principle, such a boundary contour node 23 or 24 is formed at each transition zone between two adjacent embossed elements 15 and their respective ends 15d and 15e facing one another. Two flood holes 21 are then also formed there.

In 3 a household appliance 27 for the care of laundry items is shown in a schematic representation. The household appliance 27 is in particular a washing machine. It has a housing 28 . The laundry drum 29 , which has the jacket wall 1 , is arranged in the housing 28 . In addition, the laundry drum 29 has a base plate 30 and a front base 31 indicated here only symbolically with a reference number. The longitudinal axis A is oriented here perpendicularly to the plane of the figure. The laundry drum 29 can rotate about this longitudinal axis A. In addition, a door 32 is pivotally mounted on the housing 28 . The laundry drum 29 can thus be closed at the front.

In addition, a tub 33 of the household appliance 27 is also shown in dashed lines. The washing drum 29 is accommodated in this tub 33 . In addition, in 3 carriers 34 , 35 and 36 , which are also to be understood merely as symbols, are shown, which are arranged on the inside of the casing wall 1 . The drivers 34 to 36 are provided for carrying along the laundry items that have been brought in when the laundry drum 29 rotates.

In addition, it is also provided that the casing wall 1 has a large number of flood holes. These are continuous holes so that the suds in the laundry drum 29 can escape through the flood holes and into the suds container 33 . The flood holes can be produced, for example, in the area in which the embossed structures 13, 14 are formed.

In one embodiment, a radial arrangement of the stamps relative to the center of the jacket can be dispensed with for the purpose of a simplified structure of the production plant and the limited installation space for a holding plate for a stamp of the production plant that is provided for producing the flood holes in the jacket wall. This means that the longitudinal axis of the punch is not perpendicular to the inside of the casing wall. In particular, this also means that the longitudinal axes of two stamps are not oriented at an angle to one another, but rather these longitudinal axes of the stamps are arranged parallel to one another.

This installation space is relevant in particular in the case of smaller diameters of the hollow cylinder of the jacket wall, for example between 480 mm and 520 mm.

In particular, the parallel arrangement of the stamps or the longitudinal axes of the stamps is realized in these exemplary embodiments. As a result, plate scrapers to avoid markings on the product can be reduced to a maximum. The advantage of this is the use of standard parts, in which a radial form adjustment (shell radius) can be dispensed with, since the contact surface of the sheet metal wiper has been reduced to a minimum. Consequently, marks on the product are hardly perceptible due to the parallel arrangement of a stamp die (outside the hollow cylinder) of the stamp and the stamp stripper (inside the hollow cylinder) of the stamp. The punch die and punch stripper work together to cut a flood hole in the shell wall.

Reference List

1

coat wall

2

hollow cylinder

3

expansion area

4

first edge of the hollow cylinder

5

second edge of the hollow cylinder

6

first edge

7

second edge

8th

edge strips

9

edge strips

10

cone section

11

hollow cylindrical section

11a

outside

12

cone area

13

embossing structure

14

embossing structure

15

embossing element

15a

Entry

15b

first contour section

15c

second contour section

15d

first end

15e

second end

16

mounting bracket

17

center hole

18

compensation embossing

19

connection point

20

azimuth zone

21

flood hole

22

border edge

23

Boundary Contour Node

24

Boundary Contour Node

25

first axial row

26

second axial row

27

household appliance

28

Housing

29

laundry drum

30

bottom disc

31

forehead

32

door

33

tub

34

driver

35

driver

36

driver

H

Height

A

longitudinal axis

QUOTES INCLUDED IN DESCRIPTION

This list of the documents cited by the applicant was 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.

Patent Literature Cited

• EP 1872881 A2 [0004]
• WO 2011/064201 A1 [0005]
• KR 1020200105071 A [0006]

Claims (15)

Method for producing a casing wall (1) for a laundry drum (29), in particular a laundry drum (29) for a household appliance (27) for the care of laundry items, having the following steps: - Providing a metallic plate; - Shaping the metal plate into a hollow cylinder (2), so that a basic shape of the casing wall (1) of the laundry drum (29) is formed; - Generating at least one cohesive embossed structure (13, 14) in the casing wall (1), with a large number of embossed elements (15) being generated close-meshed to one another for this purpose; - Positionally defined creation of flood holes (21) on the embossing elements (15). procedure after claim 1 , wherein at least some embossed elements (15) are produced directly adjacent to one another, so that a boundary contour (15b, 15c) of one embossed element (15) is at the same time a regional boundary contour (15b, 15c) of the other embossed element (15), wherein at least one flood hole (21 ) is generated at the boundary contour (15b, 15c). procedure after claim 2 , wherein the boundary contours (15b, 15c) are produced ending in a common free edge (22), the flood hole (21), in particular completely, being produced in the edge (22). procedure after claim 2 or 3 , wherein a boundary contour (15b, 15c) of an embossing element (15), viewed in the direction of rotation about a longitudinal axis (A) of the hollow cylinder (2), is produced with a first end (15d) on which a first boundary contour node (23) on which several Boundary contours (15b, 15c), in particular contour sections (15b, 15c), ends, is produced, at least one flood hole (21), in particular exactly two flood holes (21), being produced at the first boundary contour node (23), and/or azimuthally offset to this, the boundary contour (15b, 15c) is produced with a second end (15e), at which a second boundary contour node (24) is produced, at which a plurality of boundary contours (15b, 15c), in particular contour sections (15b, 15c), end , At least one flood hole (21), in particular exactly two flood holes (21), being produced on the second boundary contour node (24). Method according to one of the preceding claims, wherein an embossing element (15) is produced as a dome curved inwards towards the longitudinal axis (A) of the hollow cylinder (2), the boundary surface of which is bulbous and at the azimuthal ends (15d, 15e) of the boundary contour (15b, 15c) tapers to a point. procedure after claim 5 , the plurality of embossed elements (15) designed in this way being produced as a honeycomb structure in the shell wall (1), in particular an axially oriented first row (25) of embossed elements (15) to a second row (26) of axially oriented embossed elements (15) overlapping the embossing elements (15) of the first row (25) by half an embossing element (15) in the azimuthal direction and overlapping the embossing elements (15) of the first row (25) by half an embossing element (25) in the axial direction will. procedure after claim 6 , wherein a plurality of flood holes (21) in the boundary contours (15b, 15c) of the embossing elements (15) of a respective row (25, 26) are produced simultaneously by a flood hole production unit of a production plant. procedure after claim 7 , wherein a plurality of flood holes (21) at the respective opposite ends (15d, 15e) of the boundary contours (15b, 15c) of the embossing elements (15) of a respective row (25, 26) are produced simultaneously. procedure after claim 8 , wherein after the creation of the flood holes (21) in a row (25, 26) of embossing elements (15), which is created in a first axial position, the hollow cylinder (2) is moved axially by a stroke corresponding to half the axial height of an embossing element (15 ) is offset, in which case flood holes (21) are then simultaneously produced at the opposite ends (15d, 15e) of the boundary contours (15d, 15e) of the embossing elements (15) of a row (26), which are axially offset by half an embossing element (15) is generated to the already punched rows (15). Method according to one of the preceding claims, wherein three separate, close-meshed embossed structures (13, 14) are produced on the casing wall (1), which are produced equidistantly in the circumferential direction about the longitudinal axis (A) of the hollow cylinder (2). procedure after claim 10 , wherein in the intermediate areas of the casing wall (1) between the embossed structures (13, 14) drivers (34, 35, 36) are produced by embossing. Method according to one of the preceding claims, wherein after the production of the hollow cylinder (2) an expansion area (3) is produced in the jacket wall (1) by embossing, which is produced as a circumferential and outwardly curved annular bead, in which expansion area (3) the to separate embossed structure (13, 14) is produced with the plurality of embossed elements (15). Method according to one of the preceding claims, wherein a base plate (30) is attached to the hollow cylinder (2) so that the laundry drum (29) is closed at one end of the hollow cylinder (2) and/or a front base (31) is attached to the hollow cylinder (2) is attached. Method according to one of the preceding claims, in which the flood holes (21) are produced as circular holes. Laundry drum (29) for a household appliance (1) for the care of laundry items, obtainable by a method according to one of the preceding claims.

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