AU3829099A

AU3829099A - Side wall for railway car and corresponding railway car body

Info

Publication number: AU3829099A
Application number: AU38290/99A
Authority: AU
Inventors: Bernard Dabezies; Pascal Delroise
Original assignee: Alstom Holdings SA
Current assignee: Alstom Holdings SA
Priority date: 1998-05-18
Filing date: 1999-05-17
Publication date: 1999-12-06
Also published as: FR2778617B1; JP2002515373A; WO1999059856A1; FR2778617A1; KR20010021995A; CA2296755A1

Description

GEC ALSTHOM S.A. Railway vehicle side wall and corresponding railway vehicle body ABSTRACT OF THE TECHNICAL CONTENT OF THE INVENTION This side wall (4) for a railway vehicle body (1) comprises a metal support framework (8) and an external metal skin (12) welded to the framework. It comprises a cantrail (10) intended to be connected to the roof of a railway vehicle body (1). Elements (14) of the support framework (8) are connected to the cantrail by laser welding (20). The metal support framework (8) extends from a lower longitudinal longeron (6) to support the said external skin (12) and the said cantrail. Application to steel railway vehicle bodies. Figure 3.

The present invention relates to a side wall for a railway vehicle body comprising a metal support framework and an external metal skin welded to the framework. 5 The invention applies particularly to railway vehicle bodies made of steel. The current trend to improve the visual appearance of railway vehicles is to make side walls with smooth exterior faces. 10 Aluminium allows such walls to be produced with a satisfactory visual appearance, thanks to shaped parts. However, the use of aluminium in railway vehicles has the result of substantially increasing the cost compared with the use of steel. 15 By contrast, in the case of steel, obtaining a skin that has a satisfactory visual appearance poses numerous problems, particularly because of the welding techniques, commonly used in the field of railways. Specifically, the use of arc welding, which involves a 20 great deal of energy, for welding the sheets that make up the skin to the support framework leads to significant distortion of these skin sheets, which means that the time spent straightening them out again has a significant impact on the cost of manufacturing 25 railway vehicles. Furthermore, resistance spot welding marks the exterior face of the skin sheets at the points where these sheets make contact with the welding electrodes. Furthermore, this type of welding is prohibited in 30 certain countries and/or certain companies. The object of the invention is to solve these problems by supplying a side wall for a railway vehicle that makes it possible to comply with the abovementioned constraints on visual appearance in an 35 economical way. To this end, the subject of the invention is a side wall for a railway vehicle body comprising a metal support framework and an external metal skin welded to the framework, characterized in that at least some -2 welds connecting the skin to the framework are laser welds made in zones of overlap between the framework and the skin, in that these welds are obtained by transparency-welding from the interior face of the side 5 wall, through elements of the support framework, and in that these welds are welds which do not come through to the exterior face of the side wall. According to particular embodiments, the side wall may have one or more of the following features, 10 taken in isolation or in combination: - it comprises a cantrail intended to be connected to the roof of a railway vehicle body, and elements of the support framework are connected to the cantrail by laser welding performed in zones of overlap 15 between these elements and the cantrail, these welds are obtained by transparency-welding from the interior face of the side wall, through elements of the framework, and these welds do not come through to the exterior face of the side wall; and 20 - these laser welds are structural load-transmitting welds. Another subject of the invention is a railway vehicle body characterized in that it comprises two side walls as defined hereinabove. 25 The invention will be better understood from reading the description which will follow, given merely by way of example, and made with reference to the appended drawings, in which: - Figure 1 is a diagrammatic cross section 30 through a railway vehicle body according to the invention; - Figure 2 is a diagrammatic partial view in perspective from the outside of a side wall of the body of Figure 1; 35 - Figure 3 is a diagrammatic partial view in perspective from the inside and with partial cutaway of the wall of Figure 2; and - 3 - Figures 4 and 5 are diagrammatic partial sections taken respectively on the lines IV-IV and V-V of Figure 3, respectively. Figure 1 diagrammatically depicts a railway 5 vehicle body 1 made of steel and which essentially comprises a chassis 2, a top or roof 3 and two side walls 4, each with its concave face facing the inside of the body 1. As the walls 4 are symmetric with one another 10 with respect to a longitudinal mid-plane of the body 1, just one of them will be described below. As illustrated in Figures 1 to 3, the wall 4 essentially comprises a lower longitudinal longeron 6 (at the bottom in Figures 1 and 3), a support framework 15 8, a bowed upper skin part or cantrail 10 and an external skin 12, which extends between the longeron 6 and the cantrail 10 and the exterior face 13 of which is smooth. The longeron 6 connects the chassis 2 to the 20 wall 4. The cantrail 10 connects the roof 3 to the side wall 4. The steel framework 8 essentially comprises uprights 14 and longitudinal section pieces or stringers 16 orthogonal to the uprights 14. 25 The uprights 14 are very thick (3 to 5 mm) U-sections (Figure 4), the lower ends (at the bottom in Figure 3) of which are fixed, for example by MIG (metal inert gas) welding to the longeron 6, and the upper ends of which are welded to the cantrail 10, as 30 described later. These uprights 14 are arranged uniformly along the side wall 4 and substantially orthogonally to the longeron 6. The stringers 16 are thick (3 to 4 mm) section 35 pieces of Q-shaped cross section (Figure 5). The elements 14 and 16 of the framework 8 are joined together, for example, by MIG welding, at the zones where they meet, forming assembly nodes. These elements 10 and 12 are, moreover, pressed and cut in - 4 the region of these assembly nodes so that they exhibit flat surfaces to which to affix the skin 12. The external skin 12 comprises, for example, thin steel sheets joined together by butt welding. The 5 thickness of these sheets is typically under 3 mm. The skin 12 is precut to form openings 19 for the windows. The skin 12 is placed on the outside of the framework 8 and is fixed to the uprights 14 by 10 laser-welded seams 20. As illustrated in Figure 4, these laser-welded seams 20 are made in the zones 21 of overlap between the skin 12 and the flat central webs 22 of the uprights 14. These welded seams 20 are obtained by transparency-welding from the interior face 15 24 of the side wall 4 (at the bottom in Figure 4) . In other words, a laser beam passes through the web 22 of the upright 14 and then locally melts the skin 12 and thus welds the upright 14 and the skin 12 together at their opposing surfaces in the zone 21 of overlap. 20 Thus, each welded seam 20 passes right through the corresponding web 22 and then passes partially through the skin 12 overlapping the web 22. These welded seams 20 do not go right through to the exterior face 13 of the skin 12. 25 In a similar way, the skin 12 is fixed to the stringers 16 by laser-welded seams 26 made in the zones 27 of overlap between the lateral flanges 28 of the stringers 16 and the skin 12. The flanges 28 have been enlarged in Figure 3 for greater clarity. The welded 30 seams 26 are made by transparency-welding from the interior face 24 of the wall 4 (to the right in Figure 5) and do not go right through to the exterior face 13 of the skin 12. As illustrated diagrammatically by cutaway in 35 Figure 3, the uprights 14 are welded to the cantrail 10 at zones 30 of overlap between the latter and the uprights 14, by continuations of the welded seam 20. Finally, the skin 12 is welded along its lower part to the longeron 6, for example by MIG welding.

- 5 This welding, which takes place after the skin 12 has been welded to the framework 8, introduces distortion which is limited because of the rigidity conferred on the skin 12 by the framework 8. 5 The welded seams 20 and 26 connecting the skin 12 to the framework 8 are structural load-transmitting welds. Thus, together with the framework 8, the skin 12 plays a part in stiffening the side wall 4 and therefore the body 1. 10 The structure described above makes it possible to obtain side walls 4 with smooth exterior faces 13 in a relatively economical way. Specifically, the type of welding selected makes it possible to limit the distortion induced in 15 the skin 12 while it is being welded to the framework 8. Thus, the operations needed to restore a satisfactory visual appearance are limited. The welded seams 20 and 26, which do not go all the way through, do not mark the exterior face 13 of the wall 4, and 20 this makes it possible to achieve the desired visual appearance. Furthermore, the structure selected for the side wall 4 allows the automated assembly of these walls in relatively short times, laser welding making it possible to achieve welding rates of 20 m/min. 25 In alternative forms which have not been depicted, the welded seams 20 and 26 may be discontinuous and the use of laser welding may be restricted to the zones where it is needed in order to ensure a satisfactory visual appearance.

Claims

1. Side wall (4) for a railway vehicle body (1) comprising a metal support framework (8) and an 5 external metal skin (12) welded to the framework (8), characterized in that it comprises a cantrail (10) intended to be connected to the roof (3) of a railway vehicle body (1), and in that elements (14) of the support structure (8) are connected to the cantrail by 10 laser welding (20), the said metal support framework (8) extending from one lower longitudinal longeron (6) to support the said external skin (12) and the said cantrail (10).

2. Wall according to Claim 1, characterized in 15 that at least some welds connecting the skin (12) to the framework (8) are laser welds made in zones (21, 27) of overlap between the framework (8) and the skin (12), in that these welds (20, 26) are obtained by transparency-welding from the interior face (24) of the 20 side wall (4), through elements (14, 16) of the support framework, and in that these welds (20, 26) are welds which do not come through to the exterior face (13) of the side wall (4).

3. Wall according to Claim 1 or 2, characterized 25 in that laser welds (20) connecting elements of the support structure (8) to the cantrail (10) are made in zones of overlap between these elements (14) and the cantrail (10), in that these welds are obtained by transparency-welding from the interior face (24) of the 30 side wall, through elements of the framework, and in that these welds (20) do not come through to the exterior face (13) of the side wall (4).

4. Wall according to any one of Claims 1 to 3, characterized in that these laser welds are structural 35 load-transmitting welds.

5. Railway vehicle body (1), characterized in that it comprises two side walls (4) according to any one of Claims 1 to 4.