EP2873472B1 - Method for producing a tubular equipment element for a rail vehicle - Google Patents

Description

The present invention relates to a method for producing a tubular fitting element for a rail vehicle according to the preamble of claim 1.

Such a method is for example in the JP-A-2003181556 disclosed.

In rail vehicle construction there is a need for weight reduction in order to be able to operate rail vehicles more energy-efficiently and economically. In particular, interior fittings such as handrails, handles and luggage racks should be designed to be as weight-saving as possible. At the same time, however, these elements must meet the necessary mechanical and safety requirements.

One object of the invention is therefore to provide a method with which weight-optimized equipment elements for rail vehicles, in particular trams, can be produced in such a way that a weight-reduced equipment element is obtained.

According to a basic idea of the invention, an internal high pressure forming process (hereinafter also: hydroforming process) is used in the production of a tubular equipment element. With the hydroforming process, the material thickness or wall thickness is reduced in selected areas of a tubular equipment element, for example a support rod. Other areas retain or receive a greater wall thickness than the areas that were processed with hydroforming (hydroforming). This allows the wall thickness to be adjusted depending on the load. In areas in which the equipment element has fastening points, for example for fastening to an inner wall, and in areas in which the equipment element has a bend, a thicker wall thickness is preferred. Other areas can be made thinner.

• Zwischen einem Bereich mit dickerer Wandstärke und einem hydrogeformten Bereich mit dünnerer Wandstärke existiert eine Übergangszone, in welcher die Wandstärke ausgehend vom Bereich mit der dickeren Wandstärke in Richtung des Bereichs mit der dünneren Wandstärke abfällt. Es hat sich gezeigt, dass mit dem Verfahren der vorliegenden Erfindung die Länge dieser Übergangszone (in Längsrichtung des rohrförmigen Produkts) bei rohrförmigen Ausstattungselementen aus Metall und insbesondere aus Stahl sehr gering eingestellt werden kann. Vorzugsweise beträgt die Länge der Übergangszone 20 mm oder weniger. Weitere bevorzugte Bereiche sind in der nachfolgenden Beschreibung angegeben. Diese Verkürzung der Übergangszone ist möglich, weil gegenüber herkömmlichen Umformverfahren, z.B. nach Reynolds (http://reynoldstechnology.biz/faqs/butted_tubing/4), kein im Inneren des Rohres liegender, formgebender Festkörper bzw. Formkörper (z.B. Dorn oder "Mandrel") für die Umformung verwendet wird. In herkömmlichen Verfahren, wie nach Reynolds, wird die Innenkontur des Rohres mit einem solchen Formkörper geformt bzw. die Form eines solchen Formkörpers abgebildet. Ferner können in herkömmlichen Verfahren verwendete Ziehringe und Stempel aufgrund der Kaltverfestigung des rohrförmigen Ausstattungselementes, die nach einer gewissen Anzahl von Umformschritten zu groß wird, in oder auf diesem stecken bleiben. Durch eine möglichst kurze Übergangszone kann ausgehend von einer dickeren Wandstärke schnell der Bereich dünnerer Wandstärke erreicht werden, wodurch die Gewichtsreduzierung nochmals erhöht wird.
• Mit dem erfindungsgemäßen Verfahren können Wanddickenunterschiede von größer als 1 mm, vorzugsweise größer 1,5 mm, erhalten werden. Durch einen großen Wanddickenunterschied ist eine besonders effektive Gewichtsreduzierung erreichbar.
• Mit dem Verfahren wird eine Härtung des Materials im Vergleich zu dem Ausgangsmaterial erzielt, die während der Kaltumformung durch die einsetzende Kaltverfestigung entsteht.

In particular, the following advantages are achieved with the method of the present invention:

• Between an area with a thicker wall thickness and a hydroformed area with a thinner wall thickness there is a transition zone in which the wall thickness decreases starting from the area with the thicker wall thickness in the direction of the area with the thinner wall thickness. It has been shown that with the method of the present invention the length of this transition zone (in the longitudinal direction of the tubular product) can be set to be very short in the case of tubular equipment elements made of metal and in particular made of steel. The length of the transition zone is preferably 20 mm or less. Further preferred ranges are given in the description below. This shortening of the transition zone is possible because, compared to conventional forming processes, e.g. according to Reynolds (http://reynoldstechnology.biz/faqs/butted_tubing/4), there is no shaping solid or shaped body (e.g. mandrel or mandrel) inside the pipe ) is used for forming. In conventional methods, such as according to Reynolds, the inner contour of the pipe is shaped with such a shaped body or the shape of such a shaped body is mapped. Furthermore, pull rings and punches used in conventional methods can get stuck in or on the tubular fitting element due to the strain hardening of the tubular equipment element, which becomes too large after a certain number of forming steps. With a transition zone that is as short as possible, starting from a thicker wall thickness, the area of thinner wall thickness can be reached quickly, which further increases the weight reduction.
• With the method according to the invention, wall thickness differences of greater than 1 mm, preferably greater than 1.5 mm, can be obtained. A particularly effective weight reduction can be achieved through a large difference in wall thickness.
• The method achieves a hardening of the material in comparison to the starting material, which occurs during the cold forming due to the onset of work hardening.

The tubular equipment element is a hollow body. The term "tubular" can mean that at the end of the process a product with closed ends or with closed cavity inside is obtained. For this purpose, pipe ends can be closed in a further process step or other components can be attached to open pipe ends, for example fastening elements, elbows, end caps, etc. . The tubular furnishing element obtained can be straight or have one or more bends. Such bends can already be present in a tube pre-product that is processed with the method according to the invention, or such bends can be produced in or according to the method according to the invention in one or more forming steps.

Hydroforming refers to a process in which an article to be formed is placed in an external mold (negative mold) and then expanded until it rests against the external mold. The expansion takes place by means of a liquid which is introduced into the interior of the article to be reshaped and on which pressure is exerted, for example with the aid of a press and press rams. The object is expanded by the pressure of the liquid until its wall is in contact with the wall of the external mold used or the mold used. After the end of the forming process, the object has assumed the internal shape of the mold. In the special case of this invention, the hydroforming process involves introducing a liquid into the interior of the pipe, pipe pre-product or intermediate product to be formed, sealing the pipe ends and exerting pressure on the liquid so that the pipe pre-product is expanded, until it rests with its wall on the tool wall.

In a variant of the method according to the invention, a second pipe section, which has a relatively smaller wall thickness and which is obtained by hydroforming, is arranged between two first pipe sections, which have a relatively greater wall thickness, with a transition area between a first and a second pipe section. In another embodiment, the equipment element has alternating first and second pipe sections, each separated by transition areas.

The cross section of the tubular equipment element can have the most varied of shapes, for example the cross section can be circular, elliptical, (rounded) angular or irregular.

In a special embodiment of the method, an equipment element is obtained which has a constant or essentially constant outer diameter, so that the appearance for passengers is uniform. For this purpose, the process is supplemented by a further forming step in addition to the hydroforming step.

1. a) Umformen eines Rohr-Vorprodukts mit konstanter oder im Wesentlichen konstanter Wanddicke zu einem Rohr-Zwischenprodukt, wobei in dem Rohr-Zwischenprodukt in dem zweiten Rohrabschnitt die Wanddicke relativ zur Wanddicke in dem ersten Rohrabschnitt verringert wird und in dem zweiten Rohrabschnitt der Außendurchmesser des Rohr-Vorprodukts relativ zu dem Außendurchmesser in dem ersten Rohrabschnitt geändert wird,
2. b) Umformen des Rohr-Zwischenprodukts, sodass ein konstanter oder im Wesentlichen konstanter Außendurchmesser erhalten wird, wobei in dem zweiten Rohrabschnitt die Wanddicke relativ zur Wanddicke in dem ersten Rohrabschnitt verringert bleibt, wobei mindestens einer der Umformschritte mit Innenhochdruckumformen erfolgt. Mit diesem Verfahren wird ein rohrförmiges Ausstattungselement erhalten, das aufgrund seines konstanten oder im Wesentlichen konstanten Außendurchmessers ein einheitliches Erscheinungsbild aufweist. Allgemeine Beispiele für Ausstattungselemente sind Haltestangen, Haltegriffe, Stangen von Gepäckablagen, rohrförmige Rahmen für Sitze, Teile für Türen, insbesondere für den Verstellmechanismus von Türen.

According to the invention, a method for producing a tubular equipment element for a rail vehicle is specified, the tubular equipment element having at least one first pipe section with a first wall thickness and at least one second pipe section with a second wall thickness, the second wall thickness being less than the first wall thickness, and the tubular furnishing element has a constant or substantially constant outer diameter, the method comprising:

1. a) Forming a pipe pre-product with constant or substantially constant wall thickness to an intermediate pipe product, the wall thickness of the pipe intermediate product in the second pipe section being reduced relative to the wall thickness in the first pipe section and the outer diameter of the pipe in the second pipe section - the intermediate product is changed relative to the outer diameter in the first pipe section,
2. b) Forming the intermediate pipe product so that a constant or substantially constant outer diameter is obtained, the wall thickness in the second pipe section remaining reduced relative to the wall thickness in the first pipe section, at least one of the deformation steps being carried out with hydroforming. With this method, a tubular furnishing element is obtained which, due to its constant or essentially constant outer diameter, has a uniform appearance. General examples of equipment elements are handrails, handholds, rods for luggage racks, tubular frames for seats, parts for doors, in particular for the adjustment mechanism of doors.

As stated in this special variant, at least one of the forming steps is carried out with hydroforming. The other forming step in each case can be carried out by means of a different forming technique, for example rolling, stretching, roller burnishing, pressing.

The reshaping in step b) given above ensures that the at least one second pipe section has the same or essentially the same external diameter as the at least one first pipe section. As a result, the change in the outer diameter of the second pipe section that took place in step a) is reversed in comparison to the outer diameter of the first pipe section. The change in the outside diameter of the second pipe section relative to the outside diameter of the first pipe section can mean that the outside diameter of the second pipe section is reduced relative to the outside diameter of the first pipe section or that it is increased relative to the outside diameter of the first pipe section, as will be done below on the basis of special variants specified. “Essentially constant” and “essentially the same” mean a deviation or reduction of at most 5% in relation to an area with a larger diameter.

In a special variant of the method, the method comprises the formation of a transition area between the first pipe section and the second pipe section, in which the wall thickness drops from the first wall thickness to the second wall thickness, the transition area in the longitudinal direction of the tubular equipment element having a length of less than or equal to 20 mm. Preferred lengths of a transition area are: less than or equal to 18 mm, less than or equal to 14 mm, or less than or equal to 12 mm. Preferred length range limits of the transition area are also: 5–20 mm, 5–18 mm, 5–14 mm or 5–12 mm.

The tubular equipment element is preferably made of metal, in particular steel or aluminum, preferably steel. A coating, for example made of plastic, can be applied to a metallic tubular element for the treatment or modification of the surface. Such a coating is preferably carried out after the method according to the invention has been carried out.

In a further embodiment of the method, a difference between the wall thickness of the first pipe section and the wall thickness of the second pipe section of greater than 1 mm, preferably greater than 1.5 mm, even more preferably greater than 2 mm, is obtained.

• in dem oben angegebenen Schritt a) in dem zweiten Rohrabschnitt der Außendurchmesser relativ zu dem Außendurchmesser in dem ersten Rohrabschnitt verkleinert wird, und
• in dem oben angegebenen Schritt b) das Umformen mit Innenhochdruckumformen erfolgt, wobei in dem zweiten Rohrabschnitt der Außendurchmesser vergrößert wird.

In a further embodiment, a method is specified, wherein

• in step a) given above, the outside diameter in the second pipe section is reduced relative to the outside diameter in the first pipe section, and
• in the above-mentioned step b) the forming takes place with internal high pressure forming, the outer diameter being increased in the second pipe section.

In this method, the wall thickness is first reduced in a second pipe section by forming, which does not have to be hydroforming, and the outer diameter is reduced in the second pipe section. A rolling or roller forming process is preferably used here. In a further step, corresponding to step b), the same external diameter is produced using hydroforming, in that the second pipe section is expanded again by hydroforming, so that as a result the same or essentially the same external diameter is obtained as in the first preliminary section, the larger one Has wall thickness. For example, in the hydroforming step, an outer shape with a constant diameter can be used or a molding tool which has such an outer shape. After the expansion with hydroforming in step b), the smaller wall thickness in the second pipe section is maintained relative to the first pipe section. This means that only the outside diameter is changed, but not or only slightly the wall thickness.

1. i. zumindest einen ersten Formbereich mit einem ersten Durchmesser, welcher einem Durchmesser des Rohr-Vorprodukts entspricht oder im Wesentlichen entspricht,
2. ii. zumindest einen zweiten Formbereich, der einen zweiten Durchmesser aufweist, welcher größer ist als der erste Durchmesser des zumindest einen ersten Formbereichs, sodass sich das Rohr-Vorprodukt nach dem Einlegen zumindest über die ersten Formbereich und den zweiten Formbereich erstreckt.

In a further embodiment of the invention, a method is specified, wherein in step a) the forming takes place with internal high pressure forming, the outer diameter in the second pipe section being increased relative to the outer diameter in the first pipe section. In this method, the wall thickness in a second pipe section is initially reduced by expanding by means of hydroforming, the outer diameter in the second pipe section being increased. In a second step b), a reshaping process is used to restore the same or essentially the same outside diameter. This can be done, for example, by rolling or Routes are made. A smaller wall thickness in the second pipe section relative to one or more first pipe sections is retained. In this embodiment, in particular, a tube pre-product is introduced into a molding tool which has an outer tube shape with a variable diameter

1. i. at least one first shaping area with a first diameter which corresponds to or substantially corresponds to a diameter of the tube pre-product,
2. ii. at least one second mold area, which has a second diameter which is greater than the first diameter of the at least one first mold area, so that the tube pre-product extends after insertion at least over the first mold area and the second mold area.

In this embodiment of the method, the pipe pre-product is completely filled with pressurized liquid at least in the second molding area and expanded in the second molding area until it rests against the molding tool, the at least one second pipe section being formed in the at least one second molding area and in the at least one first mold region the at least one first pipe section is formed. A product is then obtained in which the outside diameter in the second pipe section is enlarged relative to the outside diameter in the first pipe section, corresponding to step a) of the special embodiment of the method. Subsequently, in a step b), the product obtained in this way can be reshaped to a constant external diameter or an essentially constant external diameter.

• bei dem Umformen in Schritt a) das Bilden eines dritten Rohrabschnitts in einem Endabschnitt des rohrförmigen Ausstattungselements, wobei der dritte Rohrabschnitt in Richtung des Endes des rohrförmigen Ausstattungselements eine ansteigende Wanddicke aufweist,
• Aufweiten des dritten Rohrabschnitts, oder zumindest eines Teils davon, in Richtung des Endes des rohrförmigen Ausstattungselements, wobei nach dem Aufweiten die Wanddicke des dritten Rohrabschnitts konstant oder im Wesentlichen konstant ist und wobei in dem dritten Rohrabschnitt von dem ansonsten konstanten oder im Wesentlichen konstanten Außendurchmesser des rohrförmigen Ausstattungselements abgewichen wird.

In a variant of the method, which can be combined with the variants and embodiments described above, a method is specified that comprises

• during the reshaping in step a) the formation of a third pipe section in an end section of the tubular fitting element, the third pipe section having an increasing wall thickness in the direction of the end of the tubular fitting element,
• Expanding the third pipe section, or at least a part thereof, in the direction of the end of the tubular equipment element, wherein after the expansion the wall thickness of the third pipe section is constant or essentially constant and wherein in the third pipe section of the otherwise constant or in Substantially constant outer diameter of the tubular equipment element is deviated.

In this embodiment, the tubular product has an expanded end section or a plurality of expanded end sections in which there is a deviation from the otherwise constant or substantially constant outer diameter. The widened end sections can, for example, have fastening points for fastening, in particular in the case of a holding rod. Before the expansion, the so-called third pipe section has an increasing wall thickness, the wall thickness increasing towards the end of the pipe. This means that when the tube is expanded at the end, a constant or essentially constant wall thickness is finally obtained. The widening takes place in particular in such a way that the widening increases in the direction of a pipe end, in particular increases continuously. In order to compensate for the likewise increasing stretching of the material, a wall thickness that increases in the direction of the end of the tubular object is selected so that a constant or essentially constant wall thickness is obtained after the expansion. An example of a widening is a conical or funnel-shaped widening of the pipe, the cone or funnel forming the third pipe section. For example, the third pipe section can connect to a previously mentioned second pipe section.

In a special variant of this embodiment, the method further comprises: hydroforming of the third pipe section, bulges and / or indentations being formed in the third pipe section and the wall thickness of the third pipe section being constant or essentially constant after hydroforming. The hydroforming step can be the same as the hydroforming step that has already been described above, in particular if the shaping takes place with hydroforming in the above-mentioned step b), the outer diameter being increased in the second pipe section.

In this process variant, it is only reshaped in the third pipe section by means of hydroforming, without changing or significantly changing the wall thickness. The molding tool can, for example, be designed in such a way that indentations are made in the widened third pipe section from the outside and in the In the region of bulges, the wall of the widened third pipe section is widened by means of internal liquid pressure until the wall rests against the molding tool. This process can also be referred to as a combination of pressing and hydroforming, whereby the hydroforming form can also fulfill the function of a pressing tool. Alternatively, it is possible to produce indentations with a separate pressing tool and to shape indentations with hydroforming, and preferably also indentations which may be too wide to be shaped into a final shape with hydroforming.

In addition to the creation of one or more indentations by pressure from the outside, a bulge or a re-bulge can take place in other areas by hydroforming. It is particularly preferred here that the bulge protrudes outward at most as far as the wall of the widened third pipe section protruded outward at this point. Furthermore, the deformation in this variant of the method is preferably carried out in such a way that, measured on a cross section through the widened section, the wall length before and after the deformation is the same or essentially the same, so that the wall thickness remains the same or essentially the same.

• Umformen eines Rohr-Vorprodukts mit konstanter oder im Wesentlichen konstanter Wanddicke zu einem Rohr-Zwischenprodukt, wobei ein Rohrabschnitt am Ende des Rohr-Zwischenprodukts gebildet wird, welche in Richtung des Endes des Rohr-Zwischenprodukts eine ansteigende Wanddicke aufweist,
• Aufweiten des Rohrabschnitts in Richtung des Endes des Rohr-Zwischenprodukts, wobei nach dem Aufweiten die Wanddicke des Rohrabschnitts konstant oder im Wesentlichen konstant ist.

The invention also provides a process which can also be viewed as an isolated process, comprising

• Forming a pipe intermediate product with a constant or substantially constant wall thickness to an intermediate pipe product, wherein a pipe section is formed at the end of the intermediate pipe product which has an increasing wall thickness in the direction of the end of the intermediate pipe product,
• Expanding the pipe section in the direction of the end of the pipe intermediate product, the wall thickness of the pipe section being constant or essentially constant after the expansion.

Furthermore, this method can include as an additional method step: hydroforming of the pipe section, bulges and / or indentations being formed in this pipe section and the wall thickness of the pipe section being constant or essentially constant after the hydroforming. Reference is made here to the preceding explanations.

• Anbringen von Befestigungselementen, die Befestigungsstellen aufweisen, sodass das Ausstattungselement mittels der Befestigungsstellen im Innenraum eines Schienenfahrzeugs anbringbar ist,
• Anbringen oder Ausformen von gewinkelten Endstücken an Enden des Ausstattungselements.

The methods presented in this invention can include one or more of the following steps:

• Attaching fastening elements that have fastening points so that the equipment element can be attached by means of the fastening points in the interior of a rail vehicle,
• Attachment or shaping of angled end pieces at the ends of the equipment element.

The mentioned fastening elements or angled end pieces are further elements that characterize the process product as an equipment element for a rail vehicle. Exemplary fastening elements with fastening points are flanges, angles, holding rods, which in turn can have fastening holes, a flange or an angle, widenings with holes and other known fastening elements. A mentioned angled end piece can in turn have a fastening point at its end. Fastening elements can be molded parts, which in turn can be manufactured using hydroforming. A fastening element can be attached using conventional techniques, for example by means of a screw, rivet and / or plug connection. Exemplary fastening points are previously mentioned screw holes, projections for insertion into a complementary shaped receiving element, etc.

• einen konstanten oder im Wesentlichen konstanten Außendurchmesser,
• zumindest einen ersten Rohrabschnitt mit einer ersten Wanddicke und zumindest einen zweiten Rohrabschnitt mit einer zweiten Wanddicke, wobei die zweite Wanddicke geringer ist als die erste Wanddicke,
• einen Übergangsbereich zwischen dem ersten Rohrabschnitt und dem zweiten Rohrabschnitt, in dem die Wanddicke von der ersten Wanddicke zu der zweiten Wanddicke abfällt auf,

wobei der Übergangsbereich in Längsrichtung des rohrförmigen Ausstattungselements eine Länge von kleiner oder gleich 20 mm aufweist.In a further aspect that does not relate to the invention, a tubular equipment element for a rail vehicle,

• a constant or substantially constant outside diameter,
• at least one first pipe section with a first wall thickness and at least one second pipe section with a second wall thickness, the second wall thickness being less than the first wall thickness,
• a transition area between the first pipe section and the second pipe section, in which the wall thickness drops from the first wall thickness to the second wall thickness,

wherein the transition area in the longitudinal direction of the tubular equipment element has a length of less than or equal to 20 mm.

The tubular furnishing element can have all the objective features in any combination, which have already been mentioned above on the basis of the method according to the invention. In particular, the tubular furnishing element can be obtained by a method according to the invention as described above. The transition area between the first pipe section and the second pipe section has already been explained above.

In a special variant of the tubular equipment element, the difference between the first wall thickness of the first pipe section and the second wall thickness of the second pipe section is greater than 1 mm, preferably greater than 1.5 mm and even more preferably greater than 2 mm.

As a further feature, the tubular equipment element can have a third tube section which is located in an end section of the tubular equipment element and is widened compared to other tube sections and optionally has bulges and / or indentations.

In yet another aspect that does not concern the invention, a molding tool for forming a pipe pre-product or pipe intermediate product by hydroforming has at least two modules from which an outer pipe shape can be assembled or assembled, the modules in the assembled state in the longitudinal direction of the outer pipe shape connect to each other.

Such a modularly constructed molding tool can be adapted to different lengths of a tubular equipment element. Such a modular molding tool can be used in the above-described method according to the invention when hydroforming is carried out.

In general, the molding tool not according to the invention can be used to assemble an outer tube shape of any length and shape, for example with different diameters. Modules can be combined with one another in any number and in the most varied of shapes or designs in order to produce a desired length and / or design of an outer tube shape. The outer pipe shape can have different diameters and / or one or more bends, so that a pipe product of different dimensions and / or bent can be produced.

Each module has an outer shape for a pipe section, which is arranged in the interior of the module. The outer shape in the interior of a module can also be referred to as an outer shape section, because a section of a tubular product can be shaped with it. Various external mold sections of different modules can be assembled into a complete external mold of a pipe product. Each outer mold section in the interior of a module has two accesses. In other words, each module has two openings through which the outer mold section is accessible. When two modules are put together, an opening in the first module is made to coincide with an opening in the second module, so that an elongated shape or an elongated pipe outer-shape section is created. This principle can be continued until a desired outer mold length is produced. After assembling the desired number of modules, the molding tool according to the invention is obtained in the assembled state. The assembled molding tool has two terminal modules, each of which has an opening that is still accessible in order to carry out the molding process.

Preferred materials for the mold are metal, ceramic and plastic, or a combination thereof.

The modules of the molding tool not according to the invention are preferably in two parts and form a pipe section. Two half-modules can be put together to form a module, in the interior of which the outer shape of a pipe section is arranged. The two half-modules can be mirror images of one another, but this is not absolutely necessary. Each half-module can have a connecting means, so that two half-modules can be combined to form a full module via the connecting means. In another variant, half-modules are pressed against one another by means of external pressure, for example with a press, when the hydroforming is to be carried out.

The modules or half-modules of the molding tool can have connecting means with which the individual modules or half-modules can be connected. Modules can be connected to one another with the connecting means using or including the connecting means. In particular, connecting means are set up to interact with a traction means with which a (half) module is pulled against a Another (half) module can be exercised so that the (half) modules are pressed against one another, preferably in the longitudinal direction of the outer tube shape. Exemplary traction means are: screw / nut, clamping means, such as quick release, eccentric lever, etc.

In one embodiment, the molding tool not according to the invention has positioning means with which two modules can be precisely positioned on one another. The modules can be positioned with respect to one another in such a way that partial forms, of which one is present in each module, can be put together to form an overall form.

A form-fitting connection and / or a desired alignment can preferably be produced with the positioning means. An exemplary positioning means is a combination of a hole in one module and a hole in the second module, which are brought into congruence when the modules are correctly assembled. In order to bring the holes into congruence, a connecting pin or dowel pin can be inserted into a hole on a first module, which pin engages in the hole provided in the second module when the modules are joined together. In another variant, a projection can be provided on a first module which engages in a hole in a second module.

• zumindest einen ersten Formbereich mit einem ersten Durchmesser, der einen ersten Rohrabschnitt abbildet,
• zumindest einen zweiten Formbereich mit einem zweiten Durchmesser, der einen zweiten Rohrabschnitt abbildet, wobei der zweite Durchmesser größer ist als der erste Durchmesser,

wobei das Formwerkzeug in dem ersten Formbereich und/oder im dem zweiten Formbereich aus den zumindest zwei Modulen zusammengesetzt ist oder zusammensetzbar ist, sodass die Länge des ersten Formbereichs und/oder die Länge des zweiten Formbereichs variabel einstellbar ist.In a special embodiment of the molding tool not according to the invention, the outer tube shape has:

• at least one first shaped area with a first diameter, which depicts a first pipe section,
• at least one second shaped area with a second diameter, which depicts a second pipe section, wherein the second diameter is larger than the first diameter,

wherein the molding tool is or can be assembled from the at least two modules in the first molding area and / or in the second molding area, so that the length of the first molding area and / or the length of the second molding area is variably adjustable.

Also specified is a molding tool not according to the invention with which an outer tube shape with a constant or essentially constant diameter can be produced or which has such an outer tube shape. Such a molding tool has at least two Modules from which an outer tube shape is composed or can be assembled, each of the modules having a section and the outer tube shape sections having the same or substantially the same diameter. Thus, an outer tube shape can be assembled from the modules, which has the same or essentially the same outer diameter.

The molding tool not according to the invention has at least two openings, which are preferably terminal. In particular, the openings are arranged at opposite ends of the molding tool, preferably on opposite end faces of the molding tool. The ends or end faces are preferably opposite one another in the longitudinal direction of the molding tool. A workpiece to be shaped which is inserted into the molding tool preferably protrudes from these openings in the molding tool or is flush with the edge of the molding tool. Because of or through these openings, a workpiece located in the molding tool, or a workpiece that can be introduced or arranged in the molding tool, is accessible so that liquid can be introduced into the workpiece. Furthermore, a pressure can be applied to a liquid in the interior of the workpiece to be formed through one or both of these openings. For example, a pressure is applied to the liquid by means of a sealing stamp.

With the molding tool, which is not according to the invention, any outer tube shapes can be produced. A special example is a round outer shape. In this case, each half-module can have a semicircular inner shape, so that two half-modules assembled to form a full module have a shape with a circular cross-section on the inside. Shapes deviating from a round or circular outer shape or from a round or circular tube cross-section are also conceivable.

Furthermore, the molding tool can have one or more modules with which a widened section can be produced, which has already been structurally described above.

In another aspect that does not relate to the invention, a molding tool as described above can be used for molding a pipe pre-product or pipe intermediate product by hydroforming.

Using the method according to the invention, special structures of the obtained process product or tubular equipment element were described.

Fig. 1a-d

eine erste Verfahrensvariante zur Herstellung eines rohrförmigen Elements,

Fig. 2a-c

den letzten Schritt des in Fig. 1 dargestellten Verfahrens in detaillierterer Darstellung,

Fig. 3a-b

eine alternative Verfahrensvariante des erfindungsgemäßen Verfahrens,

Fig. 4a-c

ein rohrförmiges Ausstattungsteil mit gebogenem Endstück,

Fig. 5

ein Innenausstattungselement mit Befestigungselementen,

Fig. 6

ein Formwerkzeug in geschlossenem Zustand,

Fig. 7

ein Formwerkzeug in geöffnetem Zustand,

Fig. 8

ein Querschnitt durch ein Formwerkzeug mit Positionierungsmitteln und

The invention is described below on the basis of exemplary embodiments. Show it:

Fig. 1a-d

a first variant of the method for producing a tubular element,

Figures 2a-c

the last step of the in Fig. 1 presented procedure in more detail,

Figures 3a-b

an alternative method variant of the method according to the invention,

Figures 4a-c

a tubular piece of equipment with a curved end piece,

Fig. 5

an interior trim element with fastening elements,

Fig. 6

a mold in the closed state,

Fig. 7

a molding tool in the open state,

Fig. 8

a cross section through a molding tool with positioning means and

In Fig. 1a is a pipe intermediate product 2 with constant wall thickness. In Figure 1b an intermediate tube product 3 is shown, which was obtained from the preliminary product 2 by forming. The forming took place with rolling or roller burnishing and it is in the pipe intermediate product 3 in Figure 1b a first pipe section 4 and a second pipe section 5 are formed, which are thinner-walled than the first pipe section 4. In the area of the second pipe section 5, the outer diameter of the intermediate product 3 is reduced.

In the forming step U of product 2 ( Fig. 1a ) into product 3 ( Figure 1b ) a third pipe section 6 is also formed, which has an increasing wall thickness in the direction of the end 7 of the pipe 3. Right in Figure 1b is an enlargement of the circled section from the middle part of Figure 1b shown. The section shows the transition from the second pipe section 5 to the third pipe section 6. In the specific example, the wall thickness in the second pipe section 5 is 1 mm and increases from the beginning of the pipe section 6 to 2 mm, to grow to 3 mm by the end 7 of the pipe .

In a further step, the pipe intermediate product 3 is first widened in the area of the third pipe section 6 (step A) and that in FIG Figure 1c Product shown 8 received. The widening AU takes place by inserting a suitable, correspondingly shaped molding tool into the open end 7 of the intermediate pipe product 3. A conically widened part 9 is obtained and an adjoining widened part 10 of constant diameter. In Figure 1c , on the right is the in Figure 1c , Center circularly marked section shown enlarged. It can be seen that the wall thickness in the expanded part is now, unlike in FIG Figure 1b , is constant, in this exemplary case 2 mm. In Figure 1c On the left, a view in the longitudinal direction of the pipe intermediate product 8 is shown, the viewer's gaze falling into the opening at the end 7. Analogous views are in the Figures 1a, 1b and 1d shown on the left.

The third pipe section 6 is located in an end section of the tubular intermediate product 8, that is to say that the end 7 of the pipe intermediate product 3, 8 or of the end product 1 is reached at the end of the third pipe section 6.

This in Figure 1c The intermediate pipe product 8 shown is formed in a final step by hydroforming (hydroforming) into the object, which is shown in FIG Fig. 1d is shown. In the hydroforming step, the second pipe section 5 is expanded so that the result is the outer diameter A, shown in FIG Fig. 1d Middle, over the first pipe section 4 and the second pipe section 5 is constant. Previously, the outside diameter A 'in section 5 was smaller than the outside diameter A in section 4 ( Figures 1d and 1c ). In the hydroforming step, in this example, the molding tool has a cylindrical shape with the diameter A in the areas 4 and 5 and in the transition area 11. This means that when the intermediate pipe product 8 is inserted Figure 1c only the outer pipe surface from the first pipe section 4 (and possibly further first pipe sections 4, not shown here) rest on the mold. These first pipe sections were formed by the forming step U (from Fig. 1a to Figure 1b ) not edited. If pressure is applied to the liquid introduced into the pipe 8 during the hydroforming step, the outer surface of the second pipe section 5 also rests against the contour of the molding tool, which was at a distance from the molding tool before the application of pressure and before the expansion.

In the hydroforming step, the third pipe section 6 is also reshaped. During the deformation, indentations 13 and a bulge 12 are formed, which are shown in FIG Fig. 1d shown on the left. The hydroforming molding tool is designed in such a way that projections are formed where the indentations 13 will later be formed, which projections press in the wall of the section 6. The wall can also be pressed inwards in the area of the later projection 12. By introducing liquid into the section 6 and applying pressure, the wall in the areas 9 and 10 is pressed against the mold again and the in Fig. 1d received final shape shown on the left. The hydroforming mold is made in such a way that the non-deformed area in section 6, the semicircle in Fig. 1d at the top left, is already in contact with the wall of the molding tool. In the bulge area 12, a bulge only takes place to such an extent that the original radius of the section 10 is not exceeded. As a result of these measures, the wall thickness remains in the in Fig. 1d deformed area shown on the left constant or essentially constant.

In a further step, not shown, the section 10 of the product 1 can be partially or completely removed. The section 10 preferably serves only as a contact surface for an injection nozzle of an hydroforming device.

Finally, the product 1 also shows a transition area 11 which lies between the first pipe section 4 and the second pipe section 5. Starting from the first pipe section 4, the wall thickness drops in the direction of the second pipe section 5, so that a variable wall thickness is formed in the transition region 11. With the method according to the invention, a particularly short transition area 11 can be produced, with length dimensions that are given in the general part of the description.

In Figures 2a-b is the hydroforming step from the process according to Fig. 1a-d shown in somewhat more detail. A molding tool 20 is used and in the closed state rests against the wall 21 of the section 4 and the wall 22 of the section 10, the molding tool 20 only resting in the area 23 and thus not completely in the third pipe section 10 second pipe section 5 is not the molding tool. For the sake of clarity, the molding tool 20 is drawn at a slight distance from all pipe walls, although in the closed state it is in contact with the areas mentioned. The ends 7, 7 'of the intermediate pipe product 8 protrude from the mold and nozzles 25 are inserted into the ends, which inject high pressure fluid into the interior of the intermediate pipe product 8, whereby the regions 11, 5 and 10' are widened. The product 1 is obtained. The design of the molding tool 20 in the area of the section 10 and the molding of indentations 13 and the bulge 12, which are shown in FIG Fig. 1d is shown. In a final step, the pipe product 1 can be cut on the dashed lines in the Figure 2c can be shortened and the product 1 'is obtained.

In the Fig. 1a-d and 2a-c the longitudinal direction of the tubular element is indicated by the arrow labeled L. The longitudinal direction could be in the Fig. 1 and 2 can also be defined as going from right to left instead of left to right.

In Figures 3a and 3b a process intermediate product and a process end product are shown, which are obtained according to another process variant. At this

Process variant takes place, starting from a tube pre-product, which is analogous to product 2 in Fig. 1a can be designed, initially an hydroforming step, with two pipe sections and transition areas being formed. In this variant of the method, the outer diameter A ″ is increased in second pipe sections 32 relative to the outer diameter in first pipe sections 31. Between first sections 31 and second sections 32, there are in each case transition areas or transition sections 33. A constant or substantially constant outer diameter A is obtained and the wall thickness in second pipe sections 32 remains reduced relative to the wall thickness in first pipe sections 31. The reshaping step U can take place, for example, by stretching, drawing or rolling. A tubular furnishing element 34 with variable wall thickness is obtained , but the same outside diameter A. This end product is in Figure 3b shown.

Figures 4a-c shows, in various sections, a further tubular furnishing element 40 which can be obtained according to a method according to the invention. The element 40 has first pipe sections 41 and a second pipe section 42. The first pipe sections 41 have a greater wall thickness than the second pipe section 42, which is particularly good in the Figures 4b and 4c , in the Figure 4a represent circularly marked detail sections can be seen. In the detailed views of the Figures 4b and 4c Transition areas 43 with variable wall thicknesses, which are designed to be particularly short in this embodiment, are also visible. The following information can be used to estimate the length of the transition regions 43 in the longitudinal direction, represented by arrows L: The inner diameter I2 in the second pipe section 41 is 25 mm and the inner diameter I1 in the first section 42 is 27.5 mm. The outside diameter A in this case is 30 mm.

The in Figure 4a The equipment element 40 shown, one of the first pipe sections 41 is bent. A bend in the product 40 is preferably located in a first pipe section that has a greater wall thickness. A bend is preferably already present in a pipe pre-product, but alternatively it can also be produced after the method according to the invention has been completed. If the bend is already present in the pipe pre-product, the forming tool used for hydroforming has an external shape that reproduces the bend, so that a Pipe pre-product or pipe intermediate product can be inserted into the molding tool used for the hydroforming process.

Fig. 5 shows further tubular equipment elements 50, 51, which are combined to form an overall element 52. In the specific example, a holding rod with terminal fastening elements 53 is shown, on which, for example, a screw connection can take place in order to attach the holding rod 52 to a wall or some other surface or other fastening points. The middle tubular element 50 can for example be structured in the same way as that in FIG Figure 3b The element 34 shown. The tubular elements 51 can be connected to the element 50 via welded connections. Alternatively, it is conceivable that the element 50 and the elements 51 form an overall element that is seamless or not produced by welded connections, which is analogous to the element 34 in FIG Figure 3b is structured. The fastening elements 53 each have a bend and a widening.

In particular, the widening can be produced by an hydroforming process, for example in a manner analogous to the hydroforming step in the process after Fig. 1a-d and Figures 2a-c , in which case there are no indentations. The element 51, comprising the parts 53 and 54, can be produced from a common intermediate product. Alternatively, the fastening elements 53 can be attached to the elements 54 later, for example by welding.

Fig. 6 shows a composite forming tool 60 for an hydroforming process for forming a pipe pre-product or pipe intermediate product. The molding tool 60 has four modules 61, 62, 63, 64, 65, from which an outer tube shape is composed. The outer shape of the pipe is off Fig. 7 evident.

The module 61 is composed of two half-modules 61a, 61b. In an analogous manner, the modules 62-65 are each composed of half-modules. The Fig. 7 shows a view in which a half module has been removed from each module so that the outer pipe shape 67, more precisely part of the outer pipe shape, is visible. The outer pipe shape 67 forms an intermediate pipe product which is shaped analogously to the intermediate pipe product 30 Fig. 3a , only one widening being shown in the case of the outer shape 67. The outer pipe shape 67 has a first region 68 which depicts a first pipe section, for example a pipe section analogous to the first Pipe section 31 from Fig. 3a . Furthermore, the outer tube shape 67 has a second region 69 with a larger diameter than in the first region 68. The shaped area 69 forms a second pipe section, for example a section analogous to one of the sections 32 in FIG Fig. 3a . In this example, the molding tool 60 is composed of three modules 62, 63, 64 in the second area 69, with FIG Fig. 6 the complete modules are shown and in Fig. 7 only the lower half-modules in this illustration. To lengthen the molding area 69, additional modules could be used that have a molded part area with a corresponding diameter, for example a module analogous to module 62 or a module analogous to module 63. Conversely, one or more modules can be removed to shorten molding area 69 , for example the module 63. Of the first form areas 68 only a part is in the Fig. 7 shown. Other suitable modules with an outer pipe section with a suitable diameter can be attached to the in Fig. 6 and 7th The shape shown can be added to the right and / or left in order to lengthen one or both of the first shape regions 68.

The modules 61 and 65 further each have a shaping area 70 for shaping a transition area, analogously for example to a transition area 33 in FIG Fig. 3a .

The composite molding tool 60 has two terminal openings 71 and 72 through which liquid can be introduced into the interior of a pipe pre-product inserted in the molding tool for the purpose of hydroforming and through which pressure can be applied to the liquid. A corresponding procedure is given in Fig. 2 , upper figure, shown. The openings are arranged at opposite ends of the molding tool 60, these being opposite ends in the longitudinal direction L here. In this example, the openings are arranged on opposite end faces 83, 84.

In Fig. 7 connection means 73, 74 are also shown. By way of example, only connecting means on one side of the half-modules 61b, 62b, 63b, 64b and 65b are provided with reference symbols. Similar connecting elements are arranged on the opposite side of the respective half-module. Each of the connecting means 73 interacts with a connecting means 74, the connecting means 73 and 74 each being arranged on different modules. The connecting means 73 and 74 have grooves which are brought together when the modules are assembled, so that an elongated groove or an elongated slot open on one side is created. A traction device can be inserted into the groove, for example a screw / nut combination, the screw head resting on the connecting device 73 and the nut resting on the connecting device 74 (or vice versa) and two half-modules being pressed against each other by tightening the nut. In this way, all of the half-modules 61b to 65b can be attached to one another and a half-shape as in FIG Fig. 7 shown. In an analogous manner, the half-modules 61a to 65a shown in FIG Fig. 6 , can be fastened to one another to form a second half-mold and both half-molds can then be combined to form a full mold 60, which is shown in Fig. 6 is shown. The two half-molds can either be connected to one another by further connecting means, not shown. The two half-molds can also be pressed against one another by a contact pressure exerted from the outside. For example, both half molds can be placed in a press.

Fig. 8 shows in a detailed representation positioning means 80 in the form of pins. All half-modules 61a to 65a and 61b to 65b have internal through-holes which, using the example of half-modules 61b to 65b, are denoted by reference numerals 81a to 81e and 82a to 82e and in FIG Fig. 8 are shown in a cross-sectional view. Fig. 8 shows a section through the half-modules 61b to 65b at the level of the through holes 81 or 82. A pin 80 can be inserted into the end of any through hole so that it still protrudes from the end of the through hole. The pin can then be inserted into the end of a through-hole in another module, so that the modules are as shown in Fig. 8 shown aligned to each other. Any other type of positioning means, such as plug connections, stops, etc., are conceivable.

Claims (7)

1. A method for producing a tubular equipment element (1; 34; 40, 50, 51) for a rail vehicle, wherein the tubular equipment element has at least one first tube portion (4; 31; 41) with a first wall thickness and at least one second tube portion (5; 32; 42) with a second wall thickness, wherein the second wall thickness is smaller than the first wall thickness, and the tubular equipment element has a constant or substantially constant outer diameter (A), characterised in that the method comprises the following steps:

   a) shaping (U; IHU) a preliminary tube product (2) of constant or substantially constant wall thickness to form an intermediate tube product (3; 30), wherein in the intermediate tube product (3; 30) the wall thickness in the second tube portion (5; 32; 42) is reduced relative to the wall thickness in the first tube portion (4; 31; 41) and
   in the second tube portion (5; 32; 42) the outer diameter (A'; A") of the preliminary tube product is changed relative to the outer diameter in the first tube portion (4; 31; 41),

   b) shaping (IHU; U) the intermediate tube product (3; 30) so that a constant or substantially constant outer diameter (A) is obtained, wherein the wall thickness in the second tube portion (5; 32; 42) remains reduced relative to the wall thickness in the first tube portion (4; 31; 41),

   wherein at least one of the shaping steps is performed by internal high pressure forming (IHU).
2. The method according to claim 1, comprising the step of

   - forming a transition region (11; 33) between the first tube portion (4; 31) and the second tube portion (5; 32), in which the wall thickness decreases from the first wall thickness to the second wall thickness, wherein the transition region (11; 33) in the longitudinal direction (L) of the tubular equipment element has a length of less than or equal to 20 mm.
3. The method according to claim 1 or 2, wherein a difference between the first wall thickness and the second wall thickness of greater than 1 mm is obtained.
4. The method according to one of claims 1-3, wherein

   - in step a) the outer diameter in the second tube portion (5) is reduced relative to the outer diameter in the first tube portion (4), and

   - in step b) the shaping is performed by internal high pressure forming, wherein the outer diameter in the second tube portion (5) is enlarged.
5. The method according to one of claims 1-3, wherein

   - in step a) the shaping is performed by internal high pressure forming, wherein the outer diameter in the second tube portion (32) is enlarged relative to the outer diameter in the first tube portion (31).
6. The method according to one of the preceding claims, comprising

   - during the shaping in step a), forming a third tube portion (6) in an end portion of the tubular equipment element, wherein the third tube portion has an increasing wall thickness in the direction of the end (7) of the tubular equipment element,

   - widening (AU) at least part of the third tube portion (6) or the entire third tube portion (6) in the direction of the end (7) of the tubular equipment element, wherein, after the widening (AU), the wall thickness of the third tube portion (6) is constant or substantially constant, and wherein in the third tube portion (6) there is a deviation from the otherwise constant or substantially constant outer diameter (A) of the tubular equipment element.
7. The method according to claim 6, comprising the step of

   - shaping the third tube portion (6) by internal high pressure forming, wherein projections (12) and/or indentations (13) are formed in the third tube portion and the wall thickness of the third tube portion (10) after the internal high pressure forming is constant or substantially constant.

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