EP1257457A1

EP1257457A1 - Flat element and method for producing a flat element

Info

Publication number: EP1257457A1
Application number: EP01917001A
Authority: EP
Inventors: Hartmut Carstensen; Peter Buchwald; Ina Meyer
Original assignee: DaimlerChrysler AG
Current assignee: Alstom Transportation Germany GmbH
Priority date: 2000-02-21
Filing date: 2001-02-17
Publication date: 2002-11-20
Also published as: SI20967A; AU2001244145A1; HUP0300346A2; CZ20022785A3; WO2001062570A1; JP2003523885A; BR0108511A; NO20023959D0; KR20030011273A; CN1420827A; RU2002123340A; NO20023959L; PL357351A1; US20040075300A1; DE10009105C1; SK12032002A3; CA2400716A1

Abstract

The invention relates to a method for producing a flat element (2) for vehicle bodies according to the sandwich construction technique. Said flat element comprises an outer cladding (4) and a hump plate (6), with edge sections (8, 10) located between them. According to the inventive method, a first step consists of at least partially bonding the edge sections (8, 10) to the hump plate (6) using a mechanical joining process. A second step consists of bonding the hump plate (6) to the outer cladding (4) by adhesion and a third step consists of at least partially joining the edge sections (8, 10) to the outer cladding (4) using a mechanical joining process. These measures result in a flat element with a high degree of transversal resistance and resistance to buckling.

Description

Flat element and method for producing a flat element

The invention relates to a method for producing a surface element for car bodies in a sandwich construction on a surface element.

Car bodies, for example for passenger traffic, are made up of various components. These components include a. Flat elements. The flat elements are made up of several sheets and semi-finished products that are joined together. Various welding techniques, such as spot welding and conventional arc welding, are used here as joining technology.

In rail vehicle construction, it has so far been customary and very generally known to design components for car bodies of rail vehicles in a differential construction, in which a framework or latticework made of profiles is provided with an outer paneling which is connected to the framework in such a way that tensile and compression-resistant flat elements are produced. The planking is in the areas between the bars on the inside also with linear, often Z-shaped

Profiles reinforced as buckling stiffeners.

DE 195 21 892 C1, for example, discloses a flat element in and a method for its production. The

Flat element comprises two cover plates and a plurality of webs stiffening and connecting the cover plates via fixed connections. The webs are arranged in a lattice shape to form cassettes. Fixed connections are made here by thermally penetrating joints

Laser welding is produced, the fixed connections being designed as weld seams which extend almost over the entire length of the components to be joined.

GB 885,279 discloses a lattice work for

Form large bodies from hat-shaped profiles that are overlapped at their intersections by hat-shaped profile knots and joined with them in a positive and non-positive manner.

In the aforementioned cases, the jointing methods used for the manufacture of the bar or lattice work, for the jointing with the external planking and the subsequent application of the linear buckling stiffeners are thermal jointing methods, at least in places. A disadvantage of all these joining methods is that high accuracy must be ensured in the shaping of the bar or lattice work and corresponding effort must be made, and that the heat introduced leads to undesirable tensions and warpage in all components, which require time-consuming and costly reworking to the desired shape and surface flatness of the flat elements manufacture and remain within the required tolerances.

In addition, there is considerable thermal distortion, which is noticeable in the appearance of dents and the

Surface quality negatively affected. Extensive straightening and tensioning work as well as reworking by grinding are necessary to compensate for the warpage. The resulting dimensional tolerances lead to an increased adjustment effort in the final assembly. The known jointing methods require extensive corrosion protection afterwards or require the use of expensive stainless steel. In order to generate a suitable flat dent resistance, it is necessary to thermally tension the flat elements in a post-treatment or to provide them with profiled buckling stiffeners.

In addition, these joining methods inhibit or prevent the use of materials that already have inorganic or organic corrosion protection layers, the manufacture of largely prefabricated components, e.g. already wear thermal insulation or a final color scheme, as well as the production of hybrid components made from different materials (including fiber composite materials).

In the manufacture of rail vehicles, attempts are therefore increasingly being made to replace the thermal joining processes with cold joining processes.

In DE 195 01 805 AI it is disclosed to join a latticework and interior bulging stiffeners with an external planking by means of an adhesive cladding. This technology cannot be used for all applications and is inexpensive. EP 0 855 978 A1 discloses at least partially flat element modules which can be produced and joined together using cold joints (for example punch rivets) in a differential construction. This technology sometimes requires a lot of effort for devices and tools, is structurally relatively unfree and complex.

These known methods for joining in the manufacture of car bodies have various disadvantages.

Hollow chamber profiles can only be designed and created with great effort, which creates expensive and inflexible cast nodes and there is no tolerance compensation. The edge designs of the flat elements in the profile / sheet area have also proven to be very complex.

The production of a frame, for example made up of webs, is also complex and costly. The use of structure-bearing foam cores is common, which in turn requires the use of expensive foams, which are only glued. Mechanical stress peaks in the edge areas cannot be avoided.

In P.Cordes, V. Huller: Modern steel lightweight structures for rail vehicle construction; Blech Rohr Profile 42 (1995) 12 p. 773 - 777 describes, among other things, the use of a stool plate. In this stool plate, a smooth sheet is connected to a second sheet into which truncated cones or truncated pyramids have been molded in a defined pattern. Smooth plate and stool plate are connected to each other via a spot weld in the stool floor. DE-AS 1 133 640 describes a wall component for

Car bodies of motor vehicles. The wall component consists of shells connected to one another in pairs, one of which is provided with cup-like depressions and the other has a substantially uniformly continuous surface, the shells being connected to one another at the depressions. When using plastic shells, the bottom surfaces of the depressions in one shell are joined to the other shell by an adhesive connection. The combined surfaces are approximately equal to the remaining free surfaces between the depressions in their staggered arrangement.

DE 197 42 772 AI includes an intermediate floor for a double-decker railway car to separate the upper floor from the lower one. The intermediate floor extends from one side of the wagon to the other and over a section of the length of the wagon. It consists of several flat, rectangular, side-by-side sandwich elements, the narrow front ends of which extend from one long side of the wagon to the other and there each on one in

Carriers lying in the longitudinal direction of the carriage rest, while their wide long sides are each connected to a hollow and flexible beam which extends transversely at least over a section of the inner width of the carriage. In one embodiment, the sandwich elements consist of two metal sheets, which have a cell structure in that depressions are formed in the metal sheets by deep drawing. The tips of the depressions touch and are welded together.

The invention is based on the object of specifying a method for producing a flat element for car bodies in a sandwich construction, with flat elements having a smaller number Tolerance range and a high surface area can be manufactured. In addition, a surface element produced by the method according to the invention is to be specified.

This object is achieved by a method for producing a surface element for car bodies in sandwich construction with the features of claim 1.

In addition, this object is achieved by a surface element produced in this way.

With the method for producing a flat element, a high shear and buckling stiffness of the flat element is achieved. There are only small tolerance ranges, and the sheet is leveled automatically. A versatile functional integration is achieved by applying the method, with emphasis on corrosion protection and sound insulation. Very low component tolerances are achieved through the use of cold joining processes. Significant financial savings are also achieved by eliminating labor-intensive processes such as straightening, sandblasting, clamping, grinding and filling. In addition, costs in the material area are also saved. Basic coats can be omitted, whereas only intermediate coats, topcoat or film are required. The present method also enables a hybrid construction as well as a modular construction. Flat elements with different profiles can be created, for example a flat or a curved side wall. The manufacture of a separate elaborate

Ribs are avoided and the use of structure-bearing foam cores is eliminated. In the first and third steps, joining is preferably carried out completely mechanically. By foregoing the use of welding processes, the advantages already stated are further optimized. Mechanical joints prevent peeling tensile forces in the adhesive.

In particular, the cold joining can be carried out with punch rivets or by means of push-through joints. A combination of both methods is also conceivable. The jointing techniques ensure joints with small tolerances, as they are difficult to calculate

Shrinking process, which cannot be avoided during welding, can be avoided during cold joining.

In a further embodiment of the invention, in the first step, posts for stabilization are arranged and fastened on the side of the cusp plate facing away from the outer paneling. Assembly in this early phase of the process simplifies the entire manufacturing process for flat elements.

The cusp plate is preferably glued to the outer paneling in a vacuum bag process. For example, the sheets to be glued are placed in an airtight packaging, for example in a film, in which a negative pressure is subsequently generated. A vacuum bag process can be used to produce flat surfaces with maximum precision in a cost-effective manner. The method proves to be independent of the size of the flat element. Elaborate devices that are dependent on the size of the flat elements for producing flat flat elements are no longer required. Advantageous further developments result from the

Dependent claims.

The invention is explained in more detail using an exemplary embodiment in conjunction with the accompanying drawings. Show it:

1 shows a detail of a flat element for car bodies in a sandwich construction in plan view m schematic representation;

2 shows a section from FIG 1 along the line A-A.

1 shows a section of a flat element 2 for car bodies in a sandwich construction m top view in a schematic representation. The flat element 2 comprises an outer panel 4 and a stool sheet 6, the outer panel 4 being shown only in FIG.

The stools of the stool sheet 6 can be formed in a flat, regular arrangement in intersecting, horizontal and vertical or m intersecting, oblique rows.

There are edge profiles 8, 10, which in this exemplary embodiment are designed as window or door frames, for mechanically connecting the outer paneling 4 to the stool sheet 6.

In addition, vertical posts 12 are arranged on the side of the stool sheet 6 facing away from the outer paneling 4 for stabilization. The flat element 2 is clamped between an elongated roof beam 14 and an underframe support 16, so that the vertical posts run perpendicular to the elongated roof support 14 and the underframe support 16. 2 shows a section of the flat element 2 from FIG. 1 along the line AA. In the present method for producing the flat element 2 for car bodies in a sandwich construction, in a first step a first section of the edge profiles 8, 10 is at least partially joined to the stool sheet 6 using a mechanical joining process. Together with the posts 12 arranged on the stool plate 6, a stiffened sandwich inner shell is already produced.

In a second step, the stool sheet 6 is glued to the outer paneling 4 with the aid of an adhesive 18. The bonding is preferably carried out in a vacuum bag process. The bonding can also be carried out in other ways. In addition, there is an insulating material 20 in the spaces formed between the outer planking 4 and the stool sheet 6. The arrangement to be glued is introduced in this exemplary embodiment in an airtight packaging, for example in a film, which is subsequently used to generate a vacuum. The pressing of the stool sheet on the outer paneling can also be done in another way.

In a third step, a second section of the edge profiles 8, 10 is at least partially joined to the outer paneling 4 using a mechanical joining process. The first and third sections can also be fully mechanically grouted.

In this example, cold joining in the first and third steps is carried out with punch rivets 22. In a further exemplary embodiment, which is not shown, cold joining is carried out by means of penetrating joints. But others can too Cold jointing techniques, for example, rivets are used.

The edge profiles at least partially have a Z profile.

With the present method for producing a flat element 2 for car bodies in sandwich construction, a high shear and buckling stiffness of the entire flat element 2 is achieved. There are only small tolerance ranges, the leveling of the outer sheet taking place automatically through the gluing process.

Claims

claims

1. Method for producing a flat element (2) for car bodies in sandwich construction, d a d u r c h g e k e n n z e i c h n e t, in a first step, a first section of the

Edge profiles (8, 10) are at least partially joined with a stool sheet (6) using a mechanical joining method,

- In a second step, the stool sheet (6) is glued to an outer panel (4), and

- In a third step, a second section of the edge profiles (8, 10) is at least partially assembled with a mechanical joining process with the outer paneling (4) for connecting the outer paneling (4) to the stool sheet (6).

2. The method of claim 1, d a d u r c h g e k e n n z e i c h n e t, that a ß is completely cold-jointed in the first and third step.

3. The method according to any one of claims 1 or 2, characterized by Cold joining with punch rivets (22).

4. The method according to any one of claims 1 or 2, g e k e n n z e i c h n e t d u r c h cold joining by means of clinching.

5. The method according to any one of claims 1 to 4, d a d u r c h g e k e n n z e i c h n e t, d a ß be arranged in the first step on the side facing away from the outer planking (4) side of the stool plate (4) post (12) for stabilization.

6. The method according to any one of claims 1 to 5, d a d u r c h g e k e n n z e i c h n e t, d a ß the hump plate (6) is glued to the outer paneling (4) in a vacuum bag process.

7. The method according to any one of claims 1 to 6, d a d u r c h g e k e n n z e i c h n e t, d a ß the edge profiles (8, 10) are at least partially designed as a Z-profile.

8. flat element (2) which is produced by a method of claims 1 to 7.

9. surface element according to claim 8, d a d u r c h g e k e n n z e i c h n e t, that a ß the stool sheet (6) with the outer paneling (4) is rigidly connected.

10. flat element (2) according to claim 9, characterized in that ß the stool of the stool sheet (6) in flat regular Arrangement in intersecting, horizontal and vertical rows are formed.

11. flat element (2) according to claim 9, d a d u r c h g e k e n n z e i c h n e t, that the stools of the stool sheet (6) are formed in a flat, regular arrangement in intersecting, oblique rows.