METHOD FOR PRODUCING A LAUNDRY DRUM WITH PRECISE POSITIONING OF AN EMBOSSED STRUCTURE AND FLOOD HOLES TO EACH OTHER, AND LAUNDRY DRUM

Description

[0001] One aspect of the invention relates to a method for producing a laundry drum for a household appliance for laundry care. Another aspect of the invention relates to a laundry drum for a household appliance for laundry care. Yet another aspect of the invention relates to a household appliance for laundry care.

[0002] Household appliances for laundry care, such as washing machines or washer-dryers, feature a laundry drum. This drum typically has a hollow cylindrical shell.

[0003] In addition, a laundry drum typically also has a rear base plate. This closes off the rear of the hollow cylindrical shell wall. The front of the laundry drum typically has a so-called end plate. The end plate and the base plate are usually separate parts from the shell wall and are connected to the shell wall. In this context, it is common practice to create fold joints between these components.

[0004] To provide sufficient storage space for laundry items, it is also known for the shell wall to have radially outwardly oriented bulges. For example, EP 1 872 881 A2 discloses a drum shell in which an embossed structure with a plurality of individual embossed elements is created. However, the embossed elements therein are 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.

[0005] Furthermore, it is also known for such a shell wall to have a large, radially expanded region. This region is located radially further outward than an end edge strip of the drum shell. Such a device is known, for example, from WO 2011 / 064201 A1. A plurality of holes are formed in the radially expanded region of the drum shell.

[0006] Furthermore, a laundry drum with a drum shell is known from KR 10 2020 0105071 A. Larger, radially outwardly projecting embossed areas are formed in the drum shell. A plurality of holes are formed in each of these embossed areas.

[0007] Furthermore, WO 98 / 20195 A1 is known, which shows a manufacturing method for a laundry drum from the prior art.

[0008] Further methods for producing a shell wall of a laundry drum are known from CN 104 846 589 B, US 2007 / 214630 A1 and CN 106 544 819 A. The method known from CN 104 846 589 B comprises the steps of shaping a plate into a hollow cylindrical shell wall, producing a plurality of embossed elements in the shell wall and cutting flood holes in the shell wall at the embossed elements, wherein the embossed elements and the flood holes are only produced after the hollow cylindrical shell wall has been produced.

[0009] In the case of drum shells for laundry drums, 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 shell wall. Due to tolerances, in particular those already mentioned above, the exact positioning of the flood holes for these embossed elements has so far only been possible with relatively inaccurate accuracy. Only if there is a relatively wide-meshed embossed structure can the flood holes be positioned accordingly. If the embossed elements are formed closer together, relatively large positional deviations of the flood holes can occur. This leads to the flood holes becoming degenerate in their geometry. Such deviations are also easier to perceive visually, as they can be recognized in their positional relationship to the embossed structure.Furthermore, unwanted burrs can occur on the edges of flood holes cut with a cutting tool, especially if flood holes are cut before the stamping process.

[0010] In conventional processes, the flood holes are cut into the still flat plate of the shell wall, from which the hollow cylinder is subsequently created, and then the embossed structure is introduced. Only subsequently is this flat plate rolled up into a hollow cylinder. Cutting the flood holes before creating the embossed elements is only possible in this context if the embossed elements are very small in number and relatively far apart from one another. Undesirable positional deviations between the embossed elements and the flood holes can arise, especially if, in a subsequent manufacturing process, the flood holes are first cut into a flat plate, this plate is then formed into a hollow cylinder and the abutting edges are welded accordingly, and only subsequently is the embossed structure introduced into the shell wall.

[0011] This can also lead to undesirable situations regarding the drainage of suds from the washing drum.

[0012] Another disadvantageous problem can arise when flood holes are cut into the flat plate, the plate is formed into a hollow cylinder, and a radial expansion zone is created in the shell wall before the embossed structure is created. This can then lead to 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 the direction of the main material flow during forming or expansion, becoming oval. This increases the circumference of the potentially angular cutting edge.

[0013] It is an object of the present invention to provide a method, a casing wall for a laundry drum and such a laundry drum, in which the positional accuracy between embossed elements of an embossed structure and flood holes is improved.

[0014] 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, comprising the following steps: Providing a metallic plate; forming the metallic plate into a hollow cylinder to form a basic shell wall of the laundry drum; creating at least one coherent embossed structure in the shell wall, wherein for this purpose a plurality of embossed elements are created in close proximity to one another; positionally defined creation of flood holes on the embossed elements.

[0015] This process makes it possible to first form the hollow cylinder and thus create the basic geometry of the casing wall of the laundry drum. Only after the hollow cylinder has been created are both the embossed structure and the flood holes created in the hollow cylinder. Especially with a close-meshed design of the embossed elements in this regard, this procedure can significantly improve the positional accuracy between these embossed elements and the flood holes. This avoids unwanted deformation of the flood holes on the one hand and an off-center creation of embossed elements and flood holes on the other, as is the case with conventional processes. This enables a very precise creation of flood holes on the one hand and embossed elements arranged in close mesh with one another on the other.In particular, if, as explained in the manufacturing process, these flood holes are to be created on the embossed element itself and this element has a close mesh, the positioning accuracy can be significantly improved by the proposed method. In particular, distorted geometries of the flood holes, such as those that occur when the hollow cylinder shape is subsequently created after the flood holes have been formed in a flat plate, as is the case in the prior art, can be avoided. Likewise, tears in the created flood holes can be avoided. A close-meshed production of the embossed elements means, in particular, that the embossed elements directly adjoin one another. A partial area of ​​a boundary contour of one embossed element is simultaneously also a partial area of ​​a boundary contour of the adjacent further embossed element. This is the case with multiple embossed elements, so that the close mesh is defined thereby.

[0016] In one embodiment, the potentially defined creation of flood holes and embossed elements occurs by creating the flood holes at reference points of the embossed elements. These previously known and desired reference points therefore represent the reference point at which at least one flood hole is to be created.

[0017] A positionally defined creation therefore also means that a predetermined relationship exists between the embossed element part or the reference point and the flood hole.

[0018] Furthermore, at least some embossed elements are created directly adjacent to one another. A boundary contour of one embossed element is simultaneously 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 a further advantageous embodiment. Because the close-meshed embossed structure also forms a channel system on the inside of the hollow cylinder for draining the suds in the laundry drum. This is also close-meshed and is formed by the appropriately shaped and directly adjacent embossed elements. This also allows very defined drainage channels to be formed. Because the flood holes are then formed precisely at these respective boundary contours, the suds can be guided directly and purposefully to the flood holes in these drainage channels formed by the boundary contours.This improves the drainage of the lye.

[0019] Furthermore, this type of densely embossed structure provides an improved concept for laundry guidance within the drum. This allows for laundry items to be stored in the drum with as little contact as possible.

[0020] Furthermore, a boundary contour is created with a free edge, which delimits and separates two adjacent embossed elements. The free edge is thus the end of the boundary contour. This free edge also serves as the connecting edge between the two adjacent embossed elements. In particular, boundary contours of neighboring embossed elements now flow directly and jointly into this single edge. At least one flood hole is created in this edge. The flood hole is formed entirely within the surface of the edge.

[0021] This is a very exposed position for a flood hole, especially in conjunction with the dense structure of the embossed elements. This further enhances the aforementioned advantages.

[0022] It is precisely the prior creation of the hollow cylinder, so that the basic geometry of the shell wall exists, that enables a very precise creation of the flood holes at these very exposed points, namely at these edge edges, when the embossed elements are then arranged very closely in this regard.

[0023] In one embodiment, an embossed element is embossed as a dome-like or hump-like element. The corresponding curvature is directed towards the longitudinal axis of the laundry drum. This essentially creates a concave shape for the curved wall of an embossed element. The boundary wall of the embossed element is thus dome-shaped. An embossed element entrance, which forms the entrance to the hollow region of the embossed element, is thus located on the outside of the casing wall. This entrance is delimited by a boundary contour. The boundary contour is the edge of the boundary wall. This boundary contour is formed in particular by the peripheral edge. Thus, a partial area of ​​this boundary contour of an embossed element projects into a partial area of ​​the boundary contour of the immediately adjacent further embossed element. This transition between the boundary contours is then also the peripheral edge.The marginal edge thus also represents a relatively narrow web of such a boundary contour of embossed elements. The marginal edge is thus a narrow, continuous surface strip.

[0024] Such a border edge is therefore also a line element or a thin strip element.

[0025] The embossed element is designed as a recess. It is open to the outside, particularly through the entrance.

[0026] In one embodiment, the boundary contour of an embossed element can be designed in a drop-shaped manner. The corresponding geometry thus widens on both sides from one end and then converges again toward the other end.

[0027] In particular, the embossed structure with the embossed elements is created as a honeycomb pattern or honeycomb structure. This means that the embossed elements are arranged offset from one another in a honeycomb-like manner.

[0028] In one embodiment, an embossed element is produced with a first end, viewed in the circumferential direction around a longitudinal axis of the hollow cylinder. A first boundary contour node or edge node is formed from this first end. In particular, several boundary contours or several partial regions of boundary contours of embossed elements end at this node. At this first boundary contour node, in particular the first edge node, at least one flood hole, in particular only two flood holes, is produced. In addition to or instead of this, a second end of the embossed element is produced azimuthally offset therefrom. A second boundary contour node, in particular a second edge node, is formed at this second end. In particular, several boundary contours, in particular several partial sections of the boundary contour of several adjacent embossed elements, end at this second node.At this second boundary contour node, in particular the second boundary edge node, at least one flood hole is created. In particular, exactly two flood holes are created there.

[0029] A boundary contour is formed by, in particular, wave-shaped contour sections. These are individual sub-areas of the contour.

[0030] Due to the aforementioned geometry of the embossed elements, in particular the shape of the boundary contour at the embossed element inlet, specific drainage channels and corresponding drainage channel paths are formed on the opposite side, namely the inside of the casing wall. Since these drainage channels then also meet or merge at these first and second ends, the creation of at least one flood hole at the corresponding node is particularly advantageous. This is particularly important with regard to the lye flow on the one hand and the drainage of the lye from the laundry drum via the flood holes on the other.

[0031] The method explained above makes it particularly advantageous to be able to precisely position and create flood holes even at these very exposed points of the embossed elements.

[0032] In one embodiment, an embossed element, in particular all embossed elements, is produced as a dome curved inward toward the longitudinal axis of the hollow cylinder. Its boundary surface or boundary wall is shaped bulbously, and the boundary edge or boundary contour is tapered at the azimuthally opposite ends. This already represents the advantageous geometry of the embossed elements, as explained above.

[0033] In one embodiment, the plurality of embossed elements formed in this way is produced as a honeycomb structure in the casing wall. In particular, an axially oriented first row of embossed elements is produced in the azimuthal direction at the same azimuthal position. This first row is formed into a second row of likewise axially oriented embossed elements, which are also produced at the same azimuthal position, overlapping the embossed elements of the first row by half an embossed element in the azimuthal direction. In the axial direction, these embossed elements of the second row are produced overlapping the embossed elements of the first row by half an embossed element. This results in the advantageous honeycomb structure, in particular. A very densely packed and particularly close-meshed arrangement of the embossed elements is thereby achieved. In the series process, preferably three embossed fields or embossed structures are produced simultaneously, i.e. at the same time.It would also be possible to create these embossed fields one after the other.

[0034] In one embodiment, flood holes in the boundary edges and embossed elements of a respective row are generated simultaneously by a flood hole generation unit. This allows for particularly high symmetry and rapid generation of flood holes.

[0035] In one embodiment, flood holes are created simultaneously at the azimuthally opposite ends of the boundary edges of the embossed elements of a respective row. This also allows for a particularly precise formation of the flood holes at both ends of the respective embossed elements of a row. This enables a particularly straight axial line of the respective flood holes at the ends.

[0036] In one embodiment, after the flood holes have been created in a row of embossed elements created in a first axial position, the hollow cylinder is axially displaced by a stroke corresponding to half the axial height of an embossed element. Subsequently, the flood holes are simultaneously created at the opposite ends of the boundary edges of the embossed elements in a row, with this row being the one that is axially offset by half an embossed element from the already perforated rows. This also enables the rapid yet highly precise creation of multiple flood holes simultaneously, particularly flood holes in a correspondingly axial row of embossed elements.

[0037] In one embodiment, three separate, close-meshed embossed structures are created on the shell wall. These are arranged or created equidistant from each other in the circumferential direction around the longitudinal axis of the hollow cylinder.

[0038] In the intermediate areas of the shell wall between the embossed structures, drivers are formed.

[0039] In one embodiment, after the hollow cylinder has been produced, an expansion embossing is created in the shell wall. This defined expansion embossing forms a radially outwardly bulging expansion region. This expansion region is created as a circumferential and outwardly curved annular bead. It extends completely circumferentially around the longitudinal axis. In this respect, it is thus also formed without interruption around the longitudinal axis. In this expansion embossing, or in this expansion region, which is very large compared to an embossed element of the embossed structure, the at least one separate embossed structure with the plurality of embossed elements is created. In one embodiment, the embossed elements are generally of the same shape and size.

[0040] In one embodiment, a bottom wall or bottom plate is attached to the hollow cylinder. The bottom wall is a separate component of the laundry drum from the outer wall. The bottom wall closes the laundry drum at one axial end of the hollow cylinder.

[0041] In one embodiment, a front end cap is attached to the hollow cylinder. The front end cap is a separate component from the hollow cylinder. In particular, the connection between the front end cap and the hollow cylinder is formed by a flanging process, thus creating a seamed connection. A similar arrangement can also be provided between the hollow cylinder and the base plate.

[0042] In one embodiment, the flood holes are created as circular holes.

[0043] Thus, as already explained above, the method involves sequentially creating a plurality of flood holes. This involves sequentially cutting flood holes in the hollow cylinder of the casing wall. Provision can be made for more than 50, in particular more than 100, in particular more than 200, and in particular more than 250 flood holes to be created per embossed structure. Thus, if a casing wall has, for example, two separate embossed structures or three separate embossed structures, each of these embossed structures will in particular have this number of flood holes. Provision is made for the flood holes to be created simultaneously in their individual segments. These flood holes are cut from the inside out. They can be cut sequentially in a time interval of less than 25 seconds, in particular between 50 and 20 seconds. In one exemplary embodiment, a cutting unit of the production plant comprises, for example, 20 cutting punches.This allows 20 flood holes to be cut simultaneously. This can be done accordingly for each embossed structure. The cutting unit can thus cut two vertical rows of holes, each with 10 flood holes, simultaneously per cutting process. This has already been explained above.

[0044] In a further procedure, the casing wall can then be rotated a certain number of times, clockwise, after each cutting cut, in order to then cut the next row of flood holes. For example, if an embossed structure has embossed elements that are connected and thus tightly meshed to one another, the casing wall can be rotated seven times by a further corresponding pitch after each cutting process, in which, in particular, two parallel rows with 10 flood holes each are cut, so that an exemplary number of axial rows with odd numbers of an embossed structure are then cut.

[0045] Specifically, after cutting the eighth row of flood holes, the shell wall is excavated vertically by one pitch. This pitch is also half the size of a stamping element. In this case, it corresponds to half the axial height of a stamping element. The same process is then carried out counterclockwise to cut all flood holes in these rows of the stamping structure, and the cutting unit is operated accordingly.

[0046] This process thus enables precise positioning of the flood holes on the narrow ridges of the densely embossed structure. These narrow ridges, in particular, create the above-mentioned edge edges, which are formed as a continuous narrow surface or narrow surface strips.

[0047] Highly dimensionally stable, particularly round, flood holes can also be created. The flood holes can be formed with significantly reduced burrs, as they are no longer introduced prior to the forming process and thus prior to the creation of the hollow cylinder. Consequently, they can no longer be deformed or structurally torn during the hollow cylinder forming process. Furthermore, lower cutting forces and thus more cost-effective system technologies are becoming more important.

[0048] A further aspect of the invention relates to a casing wall, in particular a laundry drum, for a household appliance for laundry care. The casing wall, in particular the laundry drum, is obtainable in particular by a method according to the above-mentioned aspect or an advantageous embodiment thereof.

[0049] In one embodiment, the laundry drum has a close-meshed embossed structure. This means that the embossed structure has a plurality of individual embossed elements that directly adjoin one another. In particular, in this context, the boundary contours of an inlet of such a curved configuration of an embossed element merge into one another. Free edges of this boundary contour terminate in a linear edge or edge strip, into which a free edge of an adjacent boundary contour of another embossed element also ends.

[0050] Flood holes of this laundry drum are formed on these peripheral edges. In particular, they are formed entirely within these peripheral edges. In particular, they are arranged at azimuthally opposite ends of the boundary contour of an embossed element. This enables precise positioning of the flood holes at these specific positions of embossed elements. This enables a stable position of the flood holes relative to the embossed structure. A dimensionally stable design of the flood holes is 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 fracture edge.

[0051] The terms "top", "bottom", "front", "rear", "horizontal", "vertical", "depth direction", "width direction", "height direction" indicate the positions and orientations of the casing wall or the washing drum or the appliance when used and positioned as intended.

[0052] 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 respective combination specified, but also in other combinations or on their own, without departing from the scope of the invention. Thus, embodiments are 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 by separate combinations of features from the explained embodiments. 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.

[0053] Embodiments of the invention are explained in more detail below with reference to 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 casing 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.

[0054] In Fig. 1 is a schematic, perspective view of an exemplary embodiment of a casing wall 1 for a laundry drum for a household appliance for washing laundry. The drum casing or casing wall 1 has a longitudinal axis A. The casing wall 1 is, in particular, formed 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 formed completely and uninterruptedly around the longitudinal axis A. The expansion region 3 is thus more or less a circumferential bulge. In the exemplary embodiment, this expansion region 3 is formed at a distance from a first hollow cylinder edge 4 of the casing wall 1. In particular, it is also formed at a distance from a second hollow cylinder edge 5.This means that the expansion region 3 ends in a shortened or set-back manner in these opposite end hollow cylinder walls 4 and 5. 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 spaced from the first hollow cylinder edge 4. Likewise, the second edge 7 is spaced 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 delimited by this edge 6 and this hollow cylinder edge 4.

[0055] 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 delimited by the edge 7 and the hollow cylinder edge 5.

[0056] Edge strip 8 is still single-layered here, or at this point in time of manufacture of the entire laundry drum. Edge strip 9 is still single-layered here.

[0057] The expansion region 3 has a conical section 10. The conical section 10 ends directly at the first edge 6. Starting from this first edge 6, it tapers outward to form a hollow cylindrical section 11 of the expansion region 3. Accordingly, a further conical section 12 is also formed on the axially opposite side. This section ends at the second edge 7 on the one hand and at the hollow cylindrical section 11 on the other.

[0058] The edge strip 8 is annular. The edge strip 9 is annular.

[0059] 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 circumferential direction 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 circumferential direction around the longitudinal axis A. The azimuth zone 20 is provided in particular for the positioning of a carrier of a laundry drum thereon. In addition, there is also a Fig. 1 A further azimuth zone is formed between the embossed structure 14 and the Fig. 1 A third, further embossed structure, not visible, forms a further azimuth zone. These additional azimuth zones are intended to allow the arrangement of a further driver on the inside of the casing wall 1.

[0060] 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 continuous, embossed zone and is partially generated around the longitudinal axis A. Each embossed structure 13, 14 has a plurality 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 embossed elements 15 are formed directly adjacent to one another. This also means that a boundary contour of one embossed element is simultaneously the boundary contour of the adjacent embossed element. As shown in Fig. 2 As can be seen, in an advantageous embodiment, an embossed element is drop-shaped when viewed from the side of the casing wall 1. This means that, in such a side view, the boundary contour of such an embossed element 15 is drop-shaped or bulged. With the azimuthally opposite ends, this boundary contour tapers to a point. A boundary contour delimits the opening entrance of an embossed element 15 designed as a trough.

[0061] As furthermore in Fig. 1 As can be seen, this casing wall 1 has mounting recesses 16. These mounting recesses 16 are intended for attaching a driver, particularly when it is designed as a separate component.

[0062] Furthermore, 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 allows the casing wall 1 to be brought into a horizontal reference position during production after a specific intermediate manufacturing stage. This is particularly advantageous for subsequently producing the embossed structures 13, 14 during production and for being able to produce and align them precisely horizontally.

[0063] The casing wall 1 furthermore 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 exemplary embodiment, the compensation 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 thereto. In one exemplary embodiment, at least one compensation embossing 18 is formed entirely in the edge strip 8. The explanation provided in this regard and also the following explanation also apply to the edge strip 9 in another exemplary embodiment in addition to or instead of thereto.

[0064] 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 can be formed for the entire edge strip 8 such that a maximum deviation of + / - 0.3 mm is present.

[0065] This can be seen with respect to a reference height.

[0066] 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 azimuth point at which the azimuth zone 20 also extends. In particular, the at least one compensation embossing 18 is formed in its azimuthal length entirely within the azimuthal length of this azimuth zone 20. In one embodiment, it can be provided that the compensation embossing 18 is formed in the cone section 10. This can be the case completely or at least partially.

[0067] 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 creates a folded connection between the edge strip 9 and the base plate.

[0068] In one embodiment, such a laundry drum can have an end plate. This is separate from the casing wall 1. The end plate can be connected to the casing wall 1 by a flanging or folding process. In particular, the edge strip 8 is connected to this end plate by a folded connection. This is a direct connection in each case.

[0069] 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 hollow cylinder-shaped base plate of the casing wall 1 are connected to each other, in particular welded together. This is formed here in the azimuth zone 20.

[0070] To manufacture the drum wall or the shell wall 1, a base plate for the shell wall 1 is first prepared. This plate part is unrolled from a continuous roll and cut to length accordingly.

[0071] This sheet is then rolled into a hollow cylinder 2 and joined together at the facing end edges. In particular, a welded joint is created at the connection point 19. The hollow cylinder 2 thus prepared is then radially expanded in certain regions in a production facility. For this purpose, corresponding expansion elements of the production facility can be introduced into the finished hollow cylinder 2, or the hollow cylinder 2 is positioned accordingly so that it surrounds these expansion elements. The expansion elements or mold jaws are then moved radially, so that the radially bulged expansion region 3 is formed in the hollow cylinder 2.

[0072] In a further manufacturing step, the centering receptacles 17 already explained are then preferably formed.

[0073] It can be provided that the fastening receptacles 16 are formed simultaneously or before or after the creation of the centering receptacles 17.

[0074] Once the centering recesses 17 have been created, the shell wall 1, as manufactured up to that point, is axially lifted and brought into a reference position. It no longer rests with an edge on edge recesses of the production line, but is lifted in this respect. For this purpose, appropriate elements can engage in the centering recess 17, and this desired reference position, which is an exact horizontal alignment of the hollow cylinder produced in this way, is then set. In this reference position, the edge strip 8 and / or the edge strip 9 is then preferably prestressed in a further, subsequent manufacturing step. In particular, this edge strip 9 and / or 8 is azimuthally stretched in this respect.

[0075] It is possible that a deformation of a centering opening 17 may also occur during embossing. Therefore, in an advantageous embodiment, the creation of the centering openings 17 is carried out simultaneously with the production of the fastening receptacles 16. This allows these centering openings 17 to be recalibrated for subsequent processes, in particular, positioning the flange or edge strip 8, 9 for flanging or folding.

[0076] In a further manufacturing step, the embossed structures 13, 14 are then created in the expansion region 3. In particular, these separate embossed structures 13, 14 are created simultaneously. In one exemplary embodiment, the final diameter of the edge strips 8 and / or 9 is also created simultaneously with the creation of the respective embossed structure 13, 14. The prestressed state in this regard is formed into the final convex geometry of the edge strips 8, 9.

[0077] In a further, in particular subsequent, manufacturing step, the at least one compensation embossing 18 is produced.

[0078] In addition, Fig. 2 It can also be seen that a plurality of flood holes 21 are formed on the casing wall 1. The flood holes 21 are created in a positionally defined manner. They are created in a positionally defined manner on embossed elements 15. Due to the arrangement of the embossed elements 15, the flood holes 21 are formed in rows and columns.

[0079] As in Fig. 2 As can be seen, the embossed elements 15 are shaped as domes or humps that are bulged inwards, i.e. towards the longitudinal axis A. In the Fig. 2 In the view from the outside shown, they are thus essentially inward-bulging depressions. These embossed elements 15 are provided with an entrance 15a on the outer side 11a of the area 11. This entrance 15a is delimited by a boundary contour. The boundary contour has a first contour section 15b and a second contour section 15c. The two contour sections 15b and 15c are each wave-shaped. They are formed, in particular, symmetrically to a horizontal line. In the azimuthal direction, the boundary contour of an embossed element 15 has a first end 15d and an opposite further end 15e. In this side view, the entire boundary contour of this entrance 15a of an embossed element 15 is drop-shaped. At the opposite ends in the azimuthal direction, this shape of the boundary contour is tapered, in particular tapering to a point.

[0080] On this outer side 11a, sections of the boundary contours of directly adjacent and contiguous embossed elements 15 each terminate in a free edge 22. The free edge 22 is a continuous flat strip or a flat edge line. This thus delimits two adjacent embossed elements 15. The edge 22 is also formed at the respective ends 15b and 15c.

[0081] As in Fig. 2 As can be seen, the flood holes 21 are formed on these edges 22. They are formed with their entire surface in particular completely in the edges 22. For the sake of clarity, Fig. 2 only some flood holes 21 are shown as examples.

[0082] In one embodiment, the adjacent ends 15e and 15b of two embossed elements 15 arranged successively in the circumferential direction around 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 respect, further boundary wall nodes are provided. By way of example, in Fig. 2 a further boundary contour node 24 is shown, at which two ends 15e and 15b terminate or are formed on two consecutive embossed elements 15. At least one flood hole, in particular exactly two flood holes 21, is also formed on this boundary contour node 24. This is also shown in an enlarged section in Fig. 2 shown as examples for the other areas.

[0083] As furthermore in Fig. 2 As can be seen, a plurality of embossed elements 15, ten in this embodiment, are formed in an axial row in alignment with one another. In the direction of rotation around the longitudinal axis A, a plurality of embossed elements 15 are also formed in a row in the same axial position.

[0084] As can be seen, adjacent to this example in Fig. 2 A second row 26 of embossed elements 15 is formed in the first axial row 25 shown. 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 circumferential direction 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, an offset of half the axial height of an embossed element is also formed between the embossed elements 15 of the first row 25 and the embossed elements 15 of the second row 26. This is then alternated accordingly with the further rows of embossed elements 15 in this embossed structure 13. This is also the case with the advantageously present further embossed structures 15, etc. The aspects explained for the embossed structure 13 therefore also apply to the further embossed structures of the drum wall or the shell wall 1.

[0085] This results in one embodiment that a flood hole, in particular exactly two flood holes 21, is produced at each boundary contour node 23, 24 of these correspondingly arranged embossed elements 15 of the embossed structure 13.

[0086] When producing these flood hole rows, it can be provided that a corresponding cutting unit of the production line can produce twenty flood holes 21 simultaneously. These can, for example, be those flood holes in an axial row of embossed elements that are formed at the ends 15d and those flood holes that are to be produced at the opposite ends 15e of the embossed elements 15 of this 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 sequence can be different.

[0087] Starting from this approach, once these first twenty flood holes 21 have been cut, the casing wall 1 can be rotated further about the longitudinal axis A such that further flood holes 21 are created at the ends 15d and 15e of the next row 25, which is formed in the same axial position. This continues until all rows, which are formed in the same axial position, are each created with a flood hole 21 at the respective ends 15d and 15e of the respective embossed elements 15.

[0088] Subsequently, the shell wall 1 can then be displaced in the axial direction by half the height of an embossed element 15. In a correspondingly reversed manner, the flood holes 21 can then be cut that are cut for the further rows of the embossed structure 13, which are axially offset by half an embossed element 15.

[0089] Thus, a pair of flood holes 21 is formed at each boundary contour node 23, 24. This is because the ends 15d and 15e of adjacent embossed elements 15, which face each other and terminate in the respective boundary nodes 23 and 24, are each formed with one, in particular only a single, flood hole 21.

[0090] In particular, when several separate embossed structures 13, 14 are formed, the flood holes 21 are cut simultaneously in the respective embossed structures 13, 14. In this regard, three identically designed and identically operating cutting units are provided.

[0091] For the sake of clarity, Fig. 2 Only one boundary contour node 23 and one boundary contour node 24 are provided with the corresponding reference numerals. In principle, such a boundary contour node 23 and 24 is formed at each transition zone between two adjacent embossed elements 15 and their respective mutually facing ends 15d and 15e. Two flood holes 21 are then also formed there.

[0092] In Fig. 3 1 shows a schematic representation of a household appliance 27 for washing laundry. The household appliance 27 is, in particular, a washing machine. It has a housing 28. The laundry drum 29, which has the casing 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 numeral. The longitudinal axis A is oriented perpendicular to the plane of the figure. The laundry drum 29 can rotate about this longitudinal axis A. In addition, a door 32 is pivotally arranged on the housing 28. This allows the laundry drum 29 to be closed at the front.

[0093] In addition, a tub 33 of the household appliance 27 is also shown in dashed lines. The laundry drum 29 is accommodated in this tub 33. In addition, Fig. 3 Also shown are carriers 34, 35 and 36, which are arranged on the inside of the casing wall 1. The carriers 34 to 36 are intended to carry the inserted laundry items when the laundry drum 29 rotates.

[0094] Furthermore, the casing wall 1 is provided with a plurality of flood holes. These are continuous holes so that the suds in the laundry drum 29 can flow out through the flood holes and into the suds container 33. The flood holes can be created, for example, in the area where the embossed structures 13, 14 are formed.

[0095] In one embodiment, for the purpose of simplifying the design of the production system and taking into account the limited installation space for a holding plate for a punch of the production system, which is intended to create the flood holes in the shell wall, a radial arrangement of the punches relative to the shell center point can be omitted. This means that the longitudinal axis of the punch is not perpendicular to the inside of the shell wall. In particular, this also means that the longitudinal axes of two punches are not oriented at an angle to each other, but rather these longitudinal axes of the punches are arranged parallel to each other.

[0096] This installation space is particularly relevant for smaller diameters of the hollow cylinder of the shell wall, for example between 480mm and 520mm.

[0097] In particular, these embodiments implement a parallel arrangement of the punches or the longitudinal axes of the punches. This allows the number of sheet strippers to be reduced to a minimum to avoid markings on the product. The advantage of this is the use of standard parts, which eliminates the need for radial shape adjustment (shell radius) because the contact surface of the sheet stripper has been reduced to a minimum. Consequently, markings on the product are barely noticeable due to the parallel arrangement of a punch die (outside the hollow cylinder) of the punch and the punch stripper (inside the hollow cylinder) of the punch. The punch die and the punch stripper work together to cut a flood hole in the shell wall. Bezugszeichenliste

[0098] 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 8 Edge strip 9 Edge strip 10 Conical section 11 Hollow cylindrical section 11a Outside 12 Conical area 13 Embossed structure 14 Embossed structure 15 Embossed element 15a Inlet 15 First contour section 15c Second contour section 15 First end 15e Second end 16 Fastening receptacle 17 Centering opening 18 Compensation embossing 19 Connection point 20 Azimuth zone 21 Flood hole 22 Edge 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 Base plate 31Front end 32Door 33Soy container 34Driver 35Driver 36Driver hHeight ALongitudinal axis

Claims

1. Method for manufacturing a jacket wall (1) for a laundry drum (29), in particular a laundry drum (29) for a household appliance (27) 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) so that a basic shape of the jacket wall (1) of the laundry drum (29) and thus a basic geometry of the jacket wall (1) of the laundry drum (29) is formed; wherein the further steps follow only after this generation of the hollow cylinder (2); - generating at least one cohesive embossing structure (13, 14) in the jacket wall (1), wherein to this end a plurality of embossing elements (15) are generated in a close-mesh manner with respect to one another, - positionally defined generation of drainage holes (21) on the embossing elements (15), - sequentially cutting several drainage holes (21) in the hollow cylinder (2) of the jacket wall (1), wherein the drainage holes (21) are generated simultaneously in their individual segments, characterised in that - at least a few embossing elements (15) are generated directly adjoining one another so that a boundary contour (15b, 15c) of an embossing element (15) is simultaneously a boundary contour (15b, 15c) of the other embossing element (15) in regions, wherein at least one drainage hole (21) is generated at the boundary contour (15b, 15c), - the boundary contours (15b, 15c) are generated so as to end in a shared free outer edge (22), wherein the drainage hole (21) is generated in particular fully in the outer edge (22), and - the drainage holes (21) are cut from the inside out.

2. Method according to claim 1, wherein a boundary contour (15b, 15c) of an embossing element (15) is generated with a first end (15d) viewed in the peripheral direction about a longitudinal axis (A) of the hollow cylinder (2), at which first end a first boundary contour node (23), at which several boundary contours (15b, 15c), in particular contour segments (15b, 15c) end, is generated, wherein at least one drainage hole (21), in particular precisely two drainage holes (21), is generated at the first boundary contour nodes (23), and / or offset azimuthally therefrom the boundary contour (15b, 15c) is generated with a second end (15e) at which a second boundary contour node (24), at which several boundary contours (15b, 15c), in particular contour segments (15b, 14c) end, is generated, wherein at least one drainage hole (21), in particular precisely two drainage holes (21), is generated at the second boundary contour node (24).

3. Method according to one of the preceding claims, wherein an embossing element (15) is generated as a dome which is inwardly arched with respect to the longitudinal axis (A) of the hollow cylinder (2), the boundary surface of which is moulded in a bulging manner and is tapered so as to converge in a pointed manner at the azimuthal ends (15d, 15e) of the boundary contour (15b, 15c).

4. Method according to claim 3, wherein the plurality of the thus embodied embossing elements (15) are generated as a honeycomb structure in the jacket wall (1), in particular an axially oriented first row (25) of embossing elements (15), with respect to a second row (26) of axially oriented embossing elements (15), are generated so as to overlap about half an embossing element (15) with the embossing elements (15) of the first row (25) in the azimuthal direction and are generated so as to overlap about half an embossing element (25) with the embossing elements (15) of the first row (25) in the axial direction.

5. Method according to claim 4, wherein a number of drainage holes (21) in the boundary contours (15b, 15c) of the embossing elements (15) of a respective row (25, 26) are generated simultaneously by a drainage hole generation unit of a manufacturing plant.

6. Method according to claim 5, wherein a number of drainage holes (21) are generated simultaneously at the respective opposite ends (15d, 15e) of the boundary contours (15b, 15c) of the embossing elements (15) of a respective row (25, 26).

7. Method according to claim 6, wherein after generating the drainage holes (21) in a row (25, 26) of embossing elements (15), which is generated in a first axial position, the hollow cylinder (2) is offset axially by a stroke according to half an axial height of an embossing element (15), wherein drainage holes (21) are then generated simultaneously at the opposite ends (15d, 15e) of the boundary contours (15d, 15e) of the embossing elements (15) of a row (26) which is generated axially about half an embossing element (15) with respect to the already perforated rows (15).

8. Method according to one of the preceding claims, wherein three, separate close-mesh embossing structures (13, 14) are generated on the jacket wall (1), and are generated equidistantly in the peripheral direction about the longitudinal axis (A) of the hollow cylinder (2).

9. Method according to claim 8, wherein three identically embodied and identically operating drainage hole cutting units are provided and the drainage holes (21) are cut simultaneously into respective separated close-mesh embossing structures (13, 14).

10. Method according to claim 8 or 9, wherein agitators (34, 35, 36) are generated in the intermediate areas of the jacket wall (1) between the embossing structures (13, 14) by means of embossing.

11. Method according to one of the preceding claims, wherein after generating the hollow cylinder (2), an expansion region (3) in the jacket wall (1) is generated by means of embossing, which is generated as a peripherally and outwardly bulging annular ring, wherein in this expansion region (3) the embossing structure (13, 14) which is separate therefrom is generated with the plurality of embossing elements (15).

12. Method according to one of the preceding claims, wherein a base disc (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).

13. Method according to one of the preceding claims, wherein the drainage holes (21) are generated as circular holes.

14. Laundry drum (29) for a household appliance (1) for the care of items of laundry, available by means of a method according to one of the preceding claims.