Method for manufacturing a modular roof assembly for a rail vehicle body

Abstract

The invention relates to a method for manufacturing a modular roof assembly (100) for a car body for a rail vehicle, wherein at least two plate-shaped roof elements (101) are provided, and wherein the at least two roof elements (101) are fixed to each other by laser welding at two longitudinal ends (103) of the plate-shaped roof elements (101) and joined together to form the modular roof assembly (100).

Description

[0001] Method for manufacturing a modular roof assembly for a car body for a rail vehicle.

[0002] The invention relates to a method for manufacturing a modular roof assembly for a car body for a rail vehicle.

[0003] In the rail vehicle sector, almost all vehicle components are subject to stringent requirements regarding stiffness and weight. The roof assembly of a rail vehicle must therefore possess the necessary stiffness and load-bearing capacity to withstand the forces encountered during operation and maintenance. Furthermore, the roof assembly must comply with weight restrictions to prevent the rail vehicle from becoming unnecessarily heavy. In addition, the manufacturing processes for rail vehicle components are subject to economic considerations.

[0004] CN 110 466 552 A describes a roof structure of a rail vehicle as well as a rail vehicle with the roof structure.

[0005] EP 2 537 626 A1 describes a laser welding process and a laser welding joint, as well as an outer cladding sheet and a car body structure for railway vehicles formed using the process and the joint.

[0006] The invention is based on the objective of providing an improved method for manufacturing a modular roof assembly for a car body for a rail vehicle.

[0007] This problem is solved by the method for manufacturing a modular roof assembly for a car body of a rail vehicle according to independent claim 1. Advantageous embodiments are the subject of the dependent claims.

[0008] According to one aspect of the invention, a method for manufacturing a modular roof assembly for a car body for a rail vehicle is provided, wherein at least two plate-shaped roof elements are provided, and wherein the at least two roof elements are fixed to each other at two longitudinal ends of the plate-shaped roof elements via a laser welding process and joined together to form the modular roof assembly.

[0009] This achieves the technical advantage of providing an improved method for manufacturing a modular roof assembly for a rail vehicle car body. By using a modular roof assembly consisting of at least two connectable, plate-shaped roof elements, the overall length of the individual roof elements can be substantially reduced compared to the overall length of the roof assembly. This eliminates the need for costly, specialized manufacturing equipment required for producing a single-piece roof assembly, which in conventional rail vehicles can be tens of meters long. The machining of the individual roof elements, which can be reduced to a maximum length of less than 5-6 meters, can therefore be carried out using standard processing equipment.The manufacturing process can be simplified technically and made more cost-effective. By fixing at least two roof elements together to form the roof assembly using laser welding techniques, the lower energy required for laser welding compared to standard MAG welding allows the roof elements to be manufactured with a thinner wall thickness, as there is no risk of burn-through of the thinner roof elements during laser welding. This enables the production of a lighter roof assembly.

[0010] According to one embodiment, at least one roof element is provided on a top surface of the plate-shaped roof element with at least one groove extending along a longitudinal direction of the roof element.

[0011] This offers the technical advantage that the longitudinal stiffness of the roof element can be increased by means of at least one groove running along its length. This allows the wall thicknesses of the slab-shaped roof elements to be further reduced without compromising the load-bearing capacity of the roof assembly constructed in this way.

[0012] According to the invention, the at least two roof elements are provided with transverse braces extending along a transverse direction of the roof element and with longitudinal braces extending along a longitudinal direction of the roof element. This achieves the technical advantage of further increasing the load-bearing capacity and stiffness of the roof element. In particular, the load-bearing capacity and stiffness in a transverse direction of the roof element can be improved.

[0013] According to the invention, the cross braces and the longitudinal braces are fixed to an underside of the roof element by laser welding.

[0014] This offers the technical advantage that, compared to standard spot welding, laser welding for fixing the cross braces or longitudinal braces to the underside of the roof element results in a stronger fixation of the braces to the roof element by creating continuous weld seams between the braces and the roof elements. Furthermore, as is typical with spot welding, material overlaps can be avoided by directly fixing the braces with a continuous laser weld seam between the fixing edges of the braces and the respective roof elements. By avoiding the material overlaps that occur with spot welding, where the cross braces or longitudinal braces to be welded are joined together, the process is significantly improved.Since longitudinal struts have surfaces that run at least partially parallel to the roof element, laser welding can prevent corrosion between these parallel surfaces and the roof element. This eliminates the need for parallel strut surfaces and allows the struts to be fixed directly to the roof element via their respective fixing edges. As a result, the load-bearing capacity and longevity of the roof assembly can be increased.

[0015] According to one embodiment, the roof element is provided with a plurality of cross braces, wherein the plurality of cross braces are spaced apart from each other by a uniform distance.

[0016] This offers the technical advantage of standardizing the insulation to be placed in the space between the parallel cross braces. The insulation material can thus be shaped into uniform sizes, simplifying the insulation of the roof assembly.

[0017] According to one embodiment, at least one roof element is provided with an edge trim at predetermined edge sections of the roof element by laser cutting.

[0018] This offers the technical advantage of simplifying the further processing of the roof elements into modular roof assemblies through trimming. Laser cutting enables precise and rapid trimming.

[0019] According to one embodiment, a tailored blank is inserted into at least one roof element, wherein the tailored blank is fixed flush into a recess of the trimming on an edge of the roof element by means of laser welding.

[0020] This allows for the technical advantage of individually reinforcing the load-bearing capacity of each roof element. By incorporating tailored blanks at predetermined points within the roof elements where the roof assembly experiences increased stress within the rail vehicle, the overall load-bearing capacity of the roof assembly can be enhanced. The tailored blanks are inserted flush into the plate-shaped roof elements by laser welding into specially designed recesses. This eliminates the need for material doubling and the associated problems of corrosion and increased weight.

[0021] According to the invention, the at least two roof elements are convex with at least one curvature extending along the transverse direction.

[0022] This allows for the technical advantage of a further increase in the load-bearing capacity of the roof assembly, particularly in the longitudinal direction. According to one embodiment, a multiple convex curves can be formed in a single roof element.

[0023] According to the invention, the welding of the at least two roof elements to form the roof assembly, the welding of the cross braces and the longitudinal braces, and the crowning are carried out in a clamping of the at least two roof elements in a corresponding clamping device.

[0024] This offers the technical advantage of simplifying the manufacturing process for the roof assembly by allowing the aforementioned manufacturing steps to be performed in a single setup of the roof elements. The roof assembly can thus be manufactured and completed at a single production station, eliminating the need to transport the roof elements to different locations for various manufacturing steps. In addition to simplification, this also accelerates and increases the cost-efficiency of the manufacturing process.

[0025] According to one embodiment, the at least two roof elements are each provided with a roof termination, wherein the two roof terminations are fixed to two opposing longitudinal ends of the two roof elements by means of laser welding, and wherein the two roof terminations each form two longitudinal ends of the roof assembly and serve to fix the roof assembly in a rail vehicle.

[0026] This allows for the technical advantage that the completed roof assembly can be fixed within the rail vehicle via the roof termination.

[0027] According to one embodiment, the at least two roof elements are provided with planar edge regions along the longitudinal direction, wherein the planar edge regions are not affected by the curvature of the roof elements.

[0028] This offers the technical advantage that the roof assembly can be fixed by placing the planar edge area, which is unaffected by the camber and extends along a side edge of the roof elements or the modular roof assembly, onto a correspondingly planar support of a roof longitudinal beam on the side wall of a rail vehicle. This allows for simple fixation of the roof assembly to the roof longitudinal beam.

[0029] According to one embodiment, at least one roof element is manufactured by laser welding two partial plates, wherein the laser welding of the two partial plates is carried out before trimming, embossing the beads, welding the longitudinal and transverse struts, crowning, welding the at least two roof elements and attaching the roof terminations.

[0030] This offers the technical advantage that standard-sized panels or sheets can be used to manufacture the roof elements. The dimensions of the individual panels or sheets can be, for example, approximately 3 m or 2.7 m in length and approximately 1 m or 90 cm in width. Furthermore, the panels or sheets, and thus the roof elements, can have a wall thickness of, for example, 1.2 mm.

[0031] According to one embodiment, the at least two roof elements are each designed with uniform dimensions, wherein the dimensions include a length, a width and a thickness of the plate-shaped roof elements.

[0032] This offers the technical advantage that, due to the uniform dimensions of the roof elements, the individual manufacturing steps for producing the roof assembly can be carried out at standardized production stations. This further simplifies the manufacturing process of the roof assembly.

[0033] According to one embodiment, at least one roof element is provided with at least one cutout by laser cutting.

[0034] This allows for the technical advantage that by providing the roof elements with cutouts, the roof assembly is designed for the insertion of ventilation elements or the passage of further components through the roof assembly.

[0035] In one embodiment, a roof collar is fixed to at least one cutout by means of laser welding. This achieves the technical advantage that the roof collars of the cutouts improve the guidance of the components to be routed through the roof assembly. In another embodiment, the roof elements are each made of a metal material.

[0036] This allows for the technical advantage of providing a stable and durable roof assembly.

[0037] The features and advantages of this invention described above, as well as the manner in which they are achieved, will become clearer and more easily understood through the explanations of the following highly simplified, schematic representations of preferred embodiments. These show: FIG 1 a schematic perspective view of a modular roof assembly for a rail vehicle according to one embodiment; FIG 2 a schematic representation of a roof element for a modular roof assembly for a car body for a rail vehicle according to one embodiment; FIG 3 a further schematic representation of a roof element for a modular roof assembly for a car body for a rail vehicle according to a further embodiment; FIG 4 a further schematic representation of a roof element for a modular roof assembly for a car body for a rail vehicle according to a further embodiment; FIG 5 a further schematic representation of a roof element for a modular roof assembly for a car body for a rail vehicle according to a further embodiment; FIG 6 a further schematic representation of a roof element for a modular roof assembly for a car body for a rail vehicle according to a further embodiment; FIG 7 a further schematic representation of a roof element for a modular roof assembly for a car body for a rail vehicle according to a further embodiment; FIG 8 a further schematic representation of a roof element for a modular roof assembly for a car body for a rail vehicle according to a further embodiment; FIG 9 a further schematic representation of a roof element for a modular roof assembly for a car body for a rail vehicle according to a further embodiment; FIG 10 a further schematic representation of a roof element for a modular roof assembly for a car body for a rail vehicle according to a further embodiment; FIG 11 a schematic top view of a modular roof assembly for a car body for a rail vehicle according to a further embodiment; and FIG 12 Another schematic perspective view of a modular roof assembly for a car body of a rail vehicle according to a further embodiment.

[0038] FIG 1 shows a schematic perspective view of a modular roof assembly 100 for a car body for a rail vehicle according to one embodiment.

[0039] In the embodiment shown, the modular roof assembly 100 for a car body of a rail vehicle comprises four roof elements 101: a first roof element 101A, a second roof element 101B, a third roof element 101C, and a fourth roof element 101D. The roof elements 101 are each connected to one another at their longitudinal ends 103 by means of laser welds 102.

[0040] In the embodiment shown, the individual roof elements 101 have uniform dimensions, each with a length of 3 to 4 m and a width in a transverse direction y of approximately 2 m. The total longitudinal length x of the roof assembly 100 is therefore between 3 and 30 m, which corresponds to a standard length of a car body of a rail vehicle, for example a tram.

[0041] In the illustrated embodiment, the roof elements 101 each have a plurality of grooves 107 extending along the longitudinal direction x, which are spaced parallel to one another. Furthermore, the roof elements 101 have a plurality of cross braces 109 extending along the transverse direction y, which are spaced parallel to one another. In the illustrated embodiment, the second roof element 101B, the third roof element 101C, and the fourth roof element 101D also have a plurality of tailored blanks 115, which are each arranged on side edges 104 of the roof elements 101B, 101C, and 101D, respectively. In addition, the first roof element 101A, the third roof element 101C, and the fourth roof element 101D each have a plurality of cutouts 127, which each serve to allow components of the rail vehicle, such as ventilation devices or cables, to pass through the roof assembly 100.Several of the cutouts 127 are provided with corresponding roof collars 129.

[0042] In the embodiment shown, the roof assembly 100 is depicted in a perspective top view, so that the upper surfaces 105 of the roof elements 101 are shown. According to the invention, the cross braces 109 are attached to the FIG 1 The undersides of the roof elements 101, not shown, are attached so that in FIG 1 The design of the cross braces 109 is only indicated schematically.

[0043] The roof assembly 100 shown is in FIG 1 The illustrations shown are merely exemplary, and in particular, the number of roof elements 101 joined by laser welding may differ from the number shown here. Furthermore, the number of longitudinal beads 107 and transverse cross braces 109, as well as their spacing, may differ. Additionally, the number, arrangement, and shape of the tailored blanks 115 may differ from the embodiment shown here. Similarly, the design and arrangement of the cutouts 127 and the associated roof collars 129 may differ from the embodiment shown here. The same applies to the design of the roof elements 101, and in particular their shape, which in the illustrated embodiment provides a rectangular shape for the second to fourth roof elements 101B, 101C, 101D and a rectangular shape with a trapezoidal taper for the first roof element 101A.The dimensions and / or shape of the roof elements 101 and thus of the modular roof assembly 100 may differ from the example shown here, depending on the use and the respective type of rail vehicle.

[0044] Based on the following FIGN 2 bis 10 Individual manufacturing steps according to the inventive method for manufacturing a modular roof assembly 100 are illustrated and explained.

[0045] FIG 2 Figure 1 shows a schematic representation of a roof element 101 for a modular roof assembly 100 for a car body of a rail vehicle according to one embodiment. To manufacture a modular roof assembly 100 with a plurality of roof elements 101, the individual roof elements 101 can first be provided from a plurality of partial panels 126. For this purpose, the partial panels 126 can be joined together along a side edge 104 of the respective partial panels 126 by means of a laser weld 102 to form a plate-shaped roof element 101. The partial panels 126 can be joined together by performing the laser welding in the form of a butt joint. The individual partial panels 126 can be designed as metal sheets and correspond to standard dimensions. The roof elements 101 designed in this way can thus be formed with uniform lengths L and uniform widths B.The length L of such a roof element 101 can, for example, be approximately 2.7 to 3 m, while the width B of the roof element 101 can be approximately 1.8 to 2 m. The wall thicknesses of the partial plates 126, which are made of metal sheets, can range from approximately 0.8 mm to 2.5 mm. By welding the individual partial plates 126 together to form a roof element 101 using a laser welding process, such thin-walled sheets can be used, thereby reducing the weight of the entire roof assembly 100.

[0046] As an alternative to the embodiment shown here, the roof elements 101 can be designed with dimensions that differ from those mentioned here. In particular, the roof elements 101 can be formed from a different number of partial panels 126 than the number shown here.

[0047] FIG 3 Figure 1 shows a further schematic representation of a roof element 101 for a modular roof assembly 100 for a car body for a rail vehicle according to a further embodiment.

[0048] In a further manufacturing step, the provided roof elements 101 can be provided with at least one bead 107 extending along the longitudinal direction x. The bead 107 can, for example, be embossed into the sheet metal of the roof element 101 in a corresponding embossing process. The bead 107 can be embossed as a depression in the top surface 105 of the roof element 101 or alternatively as a depression in a bottom surface of the roof element 101.

[0049] In the embodiment shown, the roof element 101 has a plurality of beads 107 running parallel to each other along the x-direction. The number of six parallel beads 107 illustrated in the figure is merely exemplary and can be varied depending on the requirements for the stiffness or dimensions of the roof element 101. In the embodiment shown, each bead 107 has a bead end 108. In this embodiment, the bead end 108 is conical. As an alternative to the conical shape of the bead ends, the beads 107 can be formed with a bead end 108 of any other shape. Alternatively, the beads can extend without a corresponding bead end 108 to the longitudinal end 103 of the respective roof element 101.

[0050] FIG 4 Figure 1 shows a further schematic representation of a roof element 101 for a modular roof assembly 100 for a car body for a rail vehicle according to a further embodiment.

[0051] In a further manufacturing step, the roof elements 101, which are provided with the corrugations 107 and optionally with one or more bulges 119, can be provided with a trim 113 by means of a laser cutting process. This trim runs along an edge region of the longitudinal ends 103 or the side edges 104 of the respective roof elements 101. The laser cutting process for forming the trim 113 can also create recesses 117 in the edge regions, in particular the side edges 104 of the roof elements 101. The recesses 117 can then be filled with appropriately shaped tailored blanks. In the illustrated embodiment, the roof element 101 has two opposing, semi-elliptical recesses 117 arranged at each of the side edges 104. Alternatively, any number of recesses 117 of any desired shape and arrangement can be generated.By a further laser cutting process, the respective roof element 101 can also be provided with at least one cutout 127, which can be arranged in an interior area of ​​the roof element 101. The cutout 127 can be provided for the passage of components within the rail vehicle through the roof assembly 100. In the illustrated embodiment, any number of arbitrarily shaped cutouts 127 are shown by way of example. Depending on the requirements and vehicle type, the number, shape, and positioning of the cutouts 127 can deviate from the illustration shown here, which is merely an example.

[0052] FIG 5 Figure 1 shows a further schematic representation of a roof element 101 for a modular roof assembly 100 for a car body for a rail vehicle according to a further embodiment.

[0053] In a further process step, the roof elements 101 are crowned according to the invention with at least one curvature 119. This crowning provides the roof elements 101 with a curvature 119 extending along the transverse direction y. The curvature 119 can be provided with a predetermined radius of curvature. Furthermore, the curvature can extend over the entire length of the roof element 101 along the longitudinal direction x of the roof element. The crowning here refers to a crowning area 120 in which the curvature 119 of the roof elements 101 is effected. The crowning area 120 extends between the two parallel side edges 104 of the roof elements 101.

[0054] Along the side edges 104, a planar edge region 123 extends in the longitudinal direction x. This planar edge region 123 borders the cambered area 120 in the transverse direction y and is therefore not affected by the cambering. Within the planar edge region 123, the roof element 101, which is provided with the camber, continues to have a planar form without a corresponding curvature 119. The planar edge region 123 can have a width of several centimeters in the transverse direction y. The corresponding roof element 101, or the assembled modular roof assembly 100, can be fixed to the respective roof longitudinal beam by means of a corresponding support for a roof longitudinal beam via the planar edge region 123.The support of the roof longitudinal beam can be designed as a corresponding planar support on which the roof assembly 100 is placed over the respective planar edge areas 123 of the interconnected roof elements 101 and connected to each other by appropriate welding.

[0055] FIG 6 Figure 1 shows a further schematic representation of a roof element 101 for a modular roof assembly 100 for a car body for a rail vehicle according to a further embodiment.

[0056] According to a further embodiment, in a further process step the roof element 101 can be provided with a plurality of bulges 119. The bulges 119 extend in the transverse direction y of the roof element 101 and can extend over the entire length of the roof element 101 in the longitudinal direction x. The bulges 119 can have different or the same radii of curvature. Furthermore, the bulges 119 can be designed as overlapping bulges 119, as shown in FIG 6 The embodiment shown comprises a first bulge 119A, a second bulge 119B, and a third bulge 119C incorporated into the roof element 101. The first bulge 119A is centrally located in the transverse direction y of the roof element 101, while the second bulge 119B and the third bulge 119C are arranged to the right and left of the first bulge 119A, respectively, in the transverse direction y. The second bulge 119B and the third bulge 119C each terminate at a side edge 104 of the roof element 101 and intersect the centrally located first bulge 119A along section lines S.

[0057] The curves 119 shown can be incorporated into the roof element 101 in addition to, or as an alternative to, the corrugations 107. The multiple curves 119 allow the radii of curvature of the individual curves 119 to be reduced compared to a single curve 119. The smaller radii of curvature provide additional stiffening of the roof element 101 in the transverse direction y.

[0058] The curves 119 can be rolled or pressed into the roof element 101 or roof elements 101.

[0059] FIG 7 Figure 1 shows a further schematic representation of a roof element 101 for a modular roof assembly 100 for a car body for a rail vehicle according to a further embodiment.

[0060] FIG 7 shows a perspective top view of the upper surface 105 of a roof element 101.

[0061] In a further process step for manufacturing the roof assembly 100, the provided roof element 101 can be provided with at least one tailored blank 115. The at least one tailored blank 115 is inserted into a recess 117 previously generated by a laser cutting process. According to one embodiment, the tailored blank 115 can be joined flush with the roof element 101 in the recess 117 by laser welding. In the embodiment shown, the roof element 101 has four tailored blanks 115, which are arranged in pairs opposite each other on the two parallel side edges 104 of the roof element 101. The tailored blanks 115 each have the semi-elliptical shape of the FIG 4 The depicted recess 117 is located at the top. As already mentioned, the recesses 117 and the associated tailored blanks 115 can be formed in any shape and at any location on the roof element 101, and the tailored blanks 115 can be connected to the roof element 101 in any number. In the embodiment shown, the roof element 101 has no cutouts 127. Alternatively, the roof element 101 can be formed analogously to the FIG 4 have at least one section 127 or a plurality of sections 127.

[0062] FIG 8 Figure 1 shows a further schematic representation of a roof element 101 for a modular roof assembly 100 for a car body for a rail vehicle according to a further embodiment.

[0063] FIG 8 shows a perspective top view of a bottom surface 111 of the roof element 101 in FIG 7 .

[0064] In a further process step, the roof element 101 is provided, according to the invention, with cross braces extending along the transverse direction y of the roof element 101. The cross braces 109 are fixed to the underside 111 of the roof element 101 by means of laser welding. In the illustrated embodiment, the roof element 101 is provided with a plurality of seven cross braces 109 arranged parallel to one another. Alternatively, any number of cross braces 109 can be provided.

[0065] FIG 9 Figure 1 shows a further schematic representation of a roof element 101 for a modular roof assembly 100 for a car body for a rail vehicle according to a further embodiment.

[0066] In a further process step, the roof element 101 is provided, according to the invention, with longitudinal struts 110 extending along the longitudinal direction x. For this purpose, the longitudinal struts 110 are fixed to the underside 111 of the roof element 101 by means of laser welding. In the illustrated embodiment, the roof element 101 has two longitudinal struts 110, each arranged at the side edges 104 of the roof element 101. Alternatively, the roof element 101 can be provided with any number of longitudinal struts 110 fixed at any position on the roof element 101.

[0067] The majority of parallel cross braces 109 can each be arranged at uniform intervals D from one another. Due to the uniformity of the intervals D of the parallel cross braces 109, insulating materials inserted into the spaces between the parallel cross braces 109 can be provided in a uniform size. This facilitates the insulation of the roof assembly 100.

[0068] In the illustrated embodiment, two of the parallel cross braces 109 have a further distance D1 that deviates from the uniform distance D. This further distance D1 is adapted to the dimensions of the cutout 127 positioned between the two parallel cross braces 109. For roof elements 101 without such cutouts 127, whose dimensions exceed the predetermined uniform distance D of the cross braces 109, all of the cross braces 109 fixed to the underside 111 can be spaced at the uniform distance D.

[0069] The cross braces 109 can be designed as cross bows and the longitudinal braces 110 can be designed as longitudinal bows.

[0070] As an alternative to the embodiment shown, longitudinal struts 110 can also be attached to the in FIG 6 The depicted section lines S of the majority of bulges 119 are arranged.

[0071] FIG 10 Figure 1 shows a further schematic representation of a roof element 101 for a modular roof assembly 100 for a car body for a rail vehicle according to a further embodiment.

[0072] According to one embodiment, the cross braces 109, which are fixed to the underside 111 of the roof elements 101 by means of laser welding, can be provided with recesses 125. The recesses 125 can be formed on a fixing edge 133 of the cross brace 109 that faces the underside 111 of the respective roof element 101. The cross braces 109 are fixed to the underside 111 of the roof element by means of laser welding via the fixing edge 133.

[0073] The recesses 125 accommodate the grooves 107, which are embossed as indentations in the upper surface 105 of the roof element 101 and correspondingly as raised sections on the underside 111 of the roof element 101. This allows the cross brace 109 to be continuously fixed to the underside 111 of the roof element 101 via the fixing edge 133. Depending on the positioning and number of grooves 107 of the roof element 101, the recesses 125 can be formed in varying numbers and positions on the fixing edge 133 of the cross braces 109.

[0074] According to one embodiment, the cross braces 109 or the longitudinal braces 110 can be designed as struts or strip elements made of metal material.

[0075] According to the invention, the above-described process steps of welding the transverse braces 109 and the longitudinal braces 110 to the undersides 111 of the roof elements 101, welding the roof elements 101 arranged one behind the other in the longitudinal direction x, and introducing the camber into the roof elements 101 are carried out in a single clamping of the roof elements 101 in a suitable clamping device. For example, the aforementioned process steps can be carried out in a clamping device used for cambering.The camber can be achieved by means of a suitably shaped support surface in which the desired curvature 119 of the roof elements 101 is incorporated, and by applying a magnetic attraction to the roof elements 101 positioned on the support surface, whereby the magnetic attraction of the roof elements 101 into the curved recess provided in the support surface gives the roof elements 101 the desired curvature 119.

[0076] FIG 11 shows a schematic top view of a modular roof assembly 100 for a car body for a rail vehicle according to a further embodiment.

[0077] In a further process step, the roof elements 101, provided with the beads 107, the cross braces 109, the longitudinal braces 110, the tailored blanks 115, and the cutouts 127 with corresponding roof collars 129, can be joined together by laser welding at their respective longitudinal ends 103. For this purpose, continuous laser welds 102 are formed at the longitudinal ends 103 of the roof elements 101, which are arranged one behind the other in the longitudinal direction x, that contact each other. This allows for a load-bearing connection between them to form a modular roof assembly 100.

[0078] FIG 12 shows another schematic perspective view of a modular roof assembly 100 for a car body for a rail vehicle according to a further embodiment.

[0079] In a further process step, the modular roof assembly 100 can also be provided with two roof terminations 121. The roof terminations 121 are each fixed to the longitudinal ends 103 of the roof elements 101, which are arranged at a front and a rear longitudinal end of the roof assembly 100, in the illustrated embodiment of the first roof element 101A and the fourth roof element 101D, by means of laser welding. For this purpose, the roof terminations 121 are shaped as collar elements and serve to fix the roof assembly 100 in the rail vehicle. Depending on the specific type of rail vehicle in which the roof assembly 100 is to be installed, the roof terminations 121 can be designed with different shapes. The roof terminations 121 shown thus serve only as exemplary embodiments of possible roof terminations 121.

[0080] By designing the roof assembly 100 as a modular roof assembly with multiple roof elements 101, it is possible to manufacture the roof assembly 100 using standard manufacturing equipment. Since the roof elements 101 are significantly shorter than the complete roof assembly 100, manufacturing steps such as embossing the beads 107, forming the trim 113, or creating the cutouts 127 can be performed on manufacturing equipment that does not need to accommodate the roof assembly 100 in its entirety. By welding the individual roof elements 101 together using laser welding, it is possible to use sheet-shaped roof elements 101 with reduced wall thickness, based on metal sheets, due to the lower heat input required for laser welding compared to MAG welding.This allows for a weight reduction in the roof assembly 100. This enables a lightweight construction.

[0081] By introducing the reinforcements in the form of the corrugations 107, the cross braces 109 and the longitudinal braces 110 and in particular by fixing the longitudinal and cross braces to the respective roof elements 101 by means of laser welding, global and local car body loads, both in static form and with regard to fatigue, of the roof assembly 100 in the rail vehicle can be met.

[0082] This ensures that the roof assembly 100 can be fully accessed.

[0083] By avoiding material doubling, which occurs during spot welding, for example of the longitudinal or transverse struts 109, robustness of the roof assembly 100 against corrosive attacks can be achieved.

[0084] This allows the roof assembly 100 to be installed in the car body of a rail vehicle, for example a tram.

[0085] Although the invention has been illustrated and described in detail by the preferred embodiment, the invention is not limited by the disclosed examples and other variations can be derived by the person skilled in the art without leaving the scope of protection of the invention.

Claims

1. Method for producing a modular roof assembly (100) for a car body for a rail vehicle, wherein at least two roof elements (101) designed in a plate-shaped manner are provided, and wherein, by way of laser welding, the at least two roof elements (101) are fixed to one another at two longitudinal ends (103) of the plate-shaped roof elements (101) in each case and are joined to form the modular roof assembly (100), wherein the at least two roof elements (101) are provided with transverse braces (109) running along a transverse direction (y) of the roof element (101) and with longitudinal braces (110) running along a longitudinal direction (x) of the roof element (101) and are raised with at least one curvature (119) running along the transverse direction (y), wherein the transverse braces (109) and the longitudinal braces (110) are fixed on an underside (111) of the roof element (101) by way of laser welding, characterised in that the welding of the at least two roof elements (101) to the roof assembly (100) and the welding of the transverse braces (109) and the longitudinal braces (110) and the raising of the at least one curvature (119) takes place in one clamping operation of the at least two roof elements (101) in a corresponding clamping apparatus.

2. Method according to claim 1, characterised in that at least one roof element (101) on an upper side (105) of the plate-shaped roof element (101) is provided with at least one beading (107) running along a longitudinal direction (x) of the roof element (101).

3. Method according to one of the preceding claims, characterised in that the roof element (101) is provided with a number of transverse braces (109), and wherein the number of transverse braces (109) are spaced apart at a uniform distance (D) from one another in each case.

4. Method according to one of the preceding claims, wherein at least one roof element (101) is provided with an edge trimming (113) by way of laser cutting on predefined edge sections of the roof element (101).

5. Method according to claim 4, wherein a tailored blank (115) is incorporated into at least one roof element (101), and wherein the tailored blank (115) is fixed flush into a recess (117) of the edge trimming (113) and to an edge (104) of the roof element (101) by means of laser welding.

6. Method according to one of the preceding claims, wherein the at least two roof elements (101) are provided with one roof closure (121) in each case, wherein the two roof closures (121) are fixed to two opposing longitudinal ends (103) of the two roof elements (101) in each case by means of laser welding, and wherein the two roof closures (121) form two longitudinal ends of the roof assembly in each case and serve for fixing the roof assembly (100) in a rail vehicle.

7. Method according to one of the preceding claims, wherein the at least two roof elements (101) are provided with planar edge regions (123) along the longitudinal direction (x), wherein the planar edge regions (123) are not affected by the raising of the roof elements (101).

8. Method according to one of the preceding claims, wherein at least one roof element (101) is manufactured by way of laser welding of two partial plates (126), and wherein the laser welding of the two partial plates (126) is performed prior to the edge trimming, the shaping of the beading (107), the welding of the transverse braces (109) and the longitudinal braces (110), the raising, the welding of the at least two roof elements (101) and the attachment of the roof closures (121).

9. Method according to one of the preceding claims, wherein the at least two roof elements (101) are designed with uniform dimensions in each case, and wherein the dimensions comprise a length (L), a width (B) and a thickness of the roof elements (101) designed in a plate-shaped manner.

10. Method according to one of the preceding claims, wherein the roof elements (101) are manufactured from a metal material in each case.

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