Patent Application
20240317278
The invention relates to a side wall for a rail vehicle in differential construction.
Large components of rail vehicles, such as side walls, end walls, roofs or underframes, can be produced from metal in “differential construction”. With such differential construction, a grid structure is constructed from panels and clad with a metal sheet, where metal sheet represents the outer skin of the large component. The resulting structure offers high strength with low weight and is suitable for production from steel or corrosion-resistant steel equally. The grid structure in this case is constructed from frames and stringers that are oriented perpendicular to the frames, these usually being welded together and to the cladding. The interconnection of the cited panels is effected via a welding method with minimal heat input, thereby ensuring that only a small amount of distortion of the structural elements occurs and that the necessary finishing, e.g., grinding and puttying, can be minimized.
Welding methods that can be automated are particularly advantageous, the accessibility of the welding points by the welding machines being an important design consideration. A frequently used welding method is spot welding, in which an electric current is conducted through two overlapping plates and these are fused locally. This always requires overlapping of the plates, which can lead to an increased mass of the large component and potentially to problems with corrosion protection at the points of overlap.
At the transition of a side wall to a roof, provision is usually made for longitudinal girders (longitudinal roof girders) that extend over the entire length of the vehicle and substantially strengthen the structure of the car body at the cited points. This is particularly necessary in the case of rail vehicles having a plurality of wide door openings, such as subways or tramways. These longitudinal roof girders can be formed as bent plate components and connected to the side wall and the roof respectively. This design is expensive because very large panels require complicated bending and the automatic production of the weld seams is made difficult due to the very limited accessibility for a spot welding machine.
The use of laser welding offers significant advantages because butt seams and T-joints can be realized via laser welding and the heat input is greatly minimized. The plate profiles having a Z-form cross section and used for conventional side walls can therefore be replaced by flat plates.
It is likewise desirable not to embody the longitudinal roof girders as separate structural elements, but to integrate their strength enhancing function already in a side wall. The prior art does not disclose a design that avoids the disadvantages described above and at the same time combines simple construction with low mass, high strength, good accessibility for rust-protection measures and suitability for automated welding by means of laser beam.
In view of the foregoing, it is therefore an object of the invention to provide a side wall of a rail vehicle, where the side wall is optimized with respect to its manufacture via laser welding and has the strength of a conventional side wall with a longitudinal roof girder.
This and other objects and advantages are achieved in accordance with the invention by a rail vehicle and side wall for a rail vehicle in differential construction, where the side wall is structured for fastening at its lower end to an underframe and at its upper end to a roof, and where the side wall comprises a grid-form network of crossrails and frames and a cladding of this grid-form network, where the cladding is produced as a single piece and comprises a vertical first section and a second section that is arranged at the upper end of the side wall and that is angled or bent relative to the first section, and comprises a cover plate that is oriented substantially vertically in the installed position of the side wall and connected to the cladding at the upper end of the second section, and comprises a plurality of ribs that are distributed along the longitudinal extent of the side wall and welded into the intermediate space between the upper section of the cladding and the cover plate.
It is thereby possible to obtain the advantage that a side wall can be constructed that is directly connectable to both an underframe and a roof, and where a longitudinal roof girder is integrated in the structure of the side wall. In particular, it is advantageously possible in this case to dispense with the costly manufacturing procedures required for the production of a longitudinal roof girder in differential construction, and instead the substantially simpler manufacture of a clad grid-form structure made of crossrails and frames is sufficient. An important advantage of the present invention lies in the suitability for production via laser welding.
In accordance with the invention, a grid-form network is constructed from crossrails and frames, and is provided with a cladding as the outer skin of the side wall. The side wall is divided into a first and a second section here, the first section corresponding to that part which is generally formed so as to be vertical and is usually fitted with door and window openings. The second section is angled or bent relative to the first section and forms that part of the side wall which represents the transition into a roof. The cladding is inventively formed as a single piece, such that no weld seam is required in the cladding at the transition point between the first and the second section.
It is nonetheless possible and can be advantageous to assemble the cladding from a plurality of individual pieces having differing properties and to bend it into the required shape as a single piece, i.e., a complete piece. It is thus possible to take locally differing strength requirements into consideration in a flexible manner, for example, by using stronger or thicker plates in the cladding at door openings.
The invention provides for connecting a cover plate, which is oriented substantially vertically in an installed position of the side wall, to the cladding at the upper end of the second section, and welding in a plurality of ribs, which are distributed along the longitudinal extent of the side wall, into the intermediate space between the upper section of the cladding and said cover plate. A girder structure with essentially triangular reinforcements is thereby produced in the upper, second section of the side wall. This represents a longitudinal roof girder that is integrated in the side wall, and is able to absorb the bending forces and moments acting thereupon. The integrated longitudinal roof girder in accordance with the invention is substantially easier to produce than conventional longitudinal roof girders in differential construction. Here, the integrated longitudinal roof girder has an essentially triangular cross section (possibly with a curved side) and is open in a downward direction because it is delimited by the cladding and the cover plate. This means that surface coatings can be applied very easily even in the interior of the integrated longitudinal roof girder.
Laser welding is particularly suitable for producing a side wall in accordance with the invention, because this method is suitable for producing butt seams with low heat input and as a consequence the side wall can be manufactured from simple, cutout panels without edge bends. Furthermore, the surface quality of the cladding on the side facing away from the weld seam is not compromised by the laser welding, and therefore no finishing, such as puttying and grinding is required there. This is particularly advantageous because this side is generally a visible surface, whose appearance is of greater importance.
It is nonetheless advantageous to include panels having more complicated shapes to minimize local concentrations of stress at the weld seams. This is particularly appropriate at the ribs, which can be provided with a flange at the open side of the integrated longitudinal roof girder. Here, the ribs are formed as flat plates with an edge bend at one side of their perimeter, for example. If this side is not straight and therefore no edge bending is possible, then the flange can also be produced as a separate panel and welded to the rib. For example, the rib can therefore have a T-form cross section and the flange can include fillets at the points of attachment to the cover plate and the uppermost crossrail.
In a further embodiment of the invention, it is advantageous to arrange at least one reinforcing plate between an uppermost crossrail and the upper section of the cladding, and weld structural elements to this. Further reinforcement of the strength of the integrated longitudinal roof girder can be achieved thereby. The reinforcing plate that is welded in, together with the uppermost stringer and part of the upper section of the cladding, form a hollow girder with a triangular cross section that is arranged in the integrated longitudinal roof girder. The reinforcing plates in this case can be formed as simple flat-plate structural elements, each of which is arranged between two ribs. In order to ensure the accessibility of the resulting hollow space for surface coatings, it is advantageous to equip the reinforcing plates and possibly the uppermost stringer with cutouts. These reinforcing plates can be provided along the entire length of the side wall, or possibly only at points where there is greater need for strength, for example, in the region of door openings.
A further increase in the strength of the side wall can be achieved by providing a closing plate that is aligned substantially parallel to the first section of the cladding, extends between two adjacent frames and between the uppermost crossrail and a crossrail below this, and is welded to these structural elements. This closing plate together with the cladding form a local box girder with high rigidity and is suitable for reinforcement of the side wall next to points of structural weakness, in particular next to door openings, and a closing plate is preferably provided at each side of a door opening in this case. Such a closing plate consequently forms a second layer to the cladding.
The present invention allows production of a side wall of a rail vehicle in differential construction, the function of a longitudinal roof girder being already built into the structure of the side wall. It is, moreover, possible in this case to use simple flat plates that are connected via laser welding, and therefore overlapping of the plates to produce spot welds can be avoided. The good/optimal accessibility that is obtained in this case with regard to all surfaces allows a surface coating for corrosion protection to be applied with particular ease.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.
The above-described properties, features and advantages of this invention and the manner in which they are achieved will become clearer and more plainly comprehensible in conjunction with the following description of an exemplary embodiment explained in more detail by way of example in more detail in conjunction with the drawings, in which:
These structural elements interact to form a hollow girder with a triangular cross section. A further reinforcement is provided via a closing plate 11 that is arranged on both sides of the door opening between the uppermost crossrail 14 and the crossrail 4 below this, and that is welded to the crossrails 4, 14 and to the adjacent frame 5 and to the door pillar 12. This closing plate 11 is arranged substantially parallel to cladding 6 in this region and distributes the forces acting in the region of the door opening into the rest of the side wall so that concentrations of stress are reduced in this region. The ribs 10 are formed as flat plates that either have an edge bend at one side or are provided with a flange that is welded on. This edge bend or the flange serves to reduce the concentration of stress at the connection points to the cover plate 9 or the uppermost frame 14.
It can also be seen that the cladding 6 has a region of greater material thickness than the other regions. These thicker regions are implemented in the longitudinal direction of the side wall at every point at which the loads are correspondingly high.
Thus, while there have been shown, described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.
| Number | Date | Country | Kind |
|---|---|---|---|
| A50592/2021 | Jul 2021 | AT | national |
This is a U.S. national stage of application No. PCT/EP2022/069412 filed 12 Jul. 2022. Priority is claimed on Austrian Application No. A50592/2021 filed 16 Jul. 2021, the content of which is incorporated herein by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/069412 | 7/12/2022 | WO |
