DE102013015279A1 - Strut for a vehicle and method of making a strut - Google Patents

Abstract

The invention relates to a strut (1) for a vehicle, wherein the strut (1) comprises a light metal or a light metal alloy. It is envisaged that the strut (1) is made of a light metal blank in one piece by massive forming, preferably by forging.

Description

The invention relates to a strut for a vehicle according to the preamble of claim 1 and to a method for producing a strut for a vehicle according to the preamble of claim 7.

Struts for vehicles, especially for motor vehicles, and methods for their production are known. From the German patent DE 10 2004 005 323 B3 shows a stiffening strut for a motor vehicle door, which is formed of aluminum tube, wherein opposite areas of the aluminum tube are stamped on each other. Generally struts are known, which consist of sheet metal profiles or tubes made of light metal, steel or fiber-reinforced plastics. Extruded profiles are also known as struts. Especially with sheet metal profiles and extruded profiles shows that they have a constant wall thickness over their entire length, the wall thickness is designed for a mechanically highly stressed area. The remaining component areas accordingly have an oversizing, as a result of which the component as a whole is relatively heavy. Since components with corresponding spatial extent are difficult to reshape, such struts are usually composed of two or more parts. For struts that consist of tubes, there is the disadvantage that they occupy a relatively large amount of space and therefore are poorly suited for tight spaces. Struts made of fiber-reinforced plastics are complicated and expensive to manufacture. Conventional struts, which include light metal or a light metal alloy, have a low kinking stability, so that they are no match for high mechanical loads, especially in an accident.

The invention is therefore an object of the invention to provide a strut and a method for producing a strut, said disadvantages do not occur. In particular, it should be possible to produce a strut with little effort in lightweight construction, which is stable even to high mechanical loads.

The object is achieved by a strut with the features of claim 1 is created. The fact that the strut is made of a light metal blank in one piece by massive forming, preferably by forging, it is at the same time light and stable. It can also be produced with little effort.

During massive forming, in particular during forging, a process-technically highly compacted structure results, so that a strut produced in this way is of high strength. In the case of massive forming, in particular during forging, it is possible to form a fiber course in the assembly as needed, in particular fibers in areas subject to high mechanical stress can be collected. Such areas then have a further increased mechanical strength. At the same time it turns out that solid-formed, in particular forged components have excellent mechanical properties, in particular with regard to a yield strength, tensile strength, elongation at break and bending angle, with corresponding values for massively formed, in particular forged light metal components significantly above the level of light metal sheets or light metal -Strangpressprofilen lie, especially at the level of steel sheets. At the same time, the solid-formed, preferably forged material is ductile. It is therefore in particular in the case of an accident sufficiently deformable to reduce impact energy and deform in a defined manner. In massive forming, especially in forging, high degrees of deformation are readily produced. The forming can be done in one step, so that the process is quick and inexpensive to carry out. Due to the high mechanical stability of the solid-formed, preferably forged strut, it is possible, their wall thickness or cross-sectional area or thickness, ie their extension perpendicular to a longitudinal direction, thin-walled or less form, as in a corresponding profile part or pipe. In addition to the use of a light metal or a light metal alloy, this contributes to the concept of lightweight construction. The fact that the strut is produced in one piece during massive forming, preferably during forging, eliminates joining steps, which considerably reduces the manufacturing outlay and the production time.

Preferably, the strut is integrally formed from a single light metal blank by massive forming, preferably forging. In this way reduces a number of components for the strut, which reduces both logistical costs, as well as manufacturing costs, while joining steps are avoided. This results in a very stable as well as inexpensive strut at the same time.

The strut is preferably designed as a reinforcing strut for a vehicle component, in particular for a motor vehicle component. Being both mechanically heavy duty and lightweight, it helps to reduce the fuel consumption of the vehicle comprising the strut.

It is preferred a strut, which consists of light metal or a light metal alloy. Preferably, the strut comprises aluminum or an aluminum alloy, more preferably one Aluminum wrought alloy, in particular the alloy EN-AW 6182 , Preferably, the strut consists of one of said materials.

A strut is also preferred, which is characterized in that it has a varying wall thickness or cross-sectional area along its extension, in particular its longitudinal extent. In this case, the term "wall thickness" a perpendicular to the longitudinal direction measured thickness of the strut is addressed. The cross-sectional area is a measure of the wall thickness or thickness for a given width of the strut. In massive forming, especially in forging, it is readily possible to form the strut with varying wall thickness or cross-sectional area. In this case, it is possible, in particular, to form regions of the strut which are subjected to high mechanical stress with a greater wall thickness or cross-sectional area than regions having a lower mechanical load. The wall thickness or cross-sectional area can therefore be tailored to the expected mechanical loads of the strut. As a result, it is not necessary to dimension the wall thickness or cross-sectional area anywhere along the strut to a mechanically highly loaded area and thus to over-dimension considerable areas of the component. By less stressed areas are formed thin-walled, preferably results in addition to the already reduced wall thickness due to the high mechanical strength of the strut a reduced weight. The wall thickness can be reduced without sacrificing the stability of the strut. Particularly preferably, the course of the wall thickness or cross-sectional area is tailored according to expected load paths with respect to a predetermined use of the strut. Accordingly, the fibers of the structure are preferably also collected or concentrated along the load paths, so that a particularly high mechanical strength results here. At the same time material is saved, which further reduces the production costs.

With regard to the wall thickness varying along the extent of the strut, at least one deformation zone is preferably provided specifically on the strut, wherein the strut deforms in the event of an accident in a predetermined manner in the region of the deformation zone. It is thus possible to tailor the strut specifically and tailor-made for use in the area of the vehicle and to define its properties locally as needed.

A strut is also preferred, which is characterized in that the wall thickness is at least 1 mm to at most 3 mm, preferably at least 1.5 mm to at most 2.5 mm, particularly preferably 2 mm. It is therefore possible to form a very thin-walled strut by massive forming, preferably forging, from a light metal blank which is nevertheless highly stable and resilient mechanically.

It is also preferred a strut, which is characterized in that it has at least one recess. The recess is preferably produced during massive forming, preferably during forging, wherein particularly preferably material is displaced from the region of the recess into other regions of the component. Preferably, areas are left out, which are free of load paths. Conversely, in an edge region of the at least one recess, there remain regions along which load paths run. In this way, the strut particularly preferably has a framework structure, wherein it is largely formed according to the loading paths. By arranging the recesses in this way, additional weight of the strut can be saved without, therefore, decreasing their mechanical strength. Thus, it is possible to design the strut weight optimized and at the same time mechanically highly stable.

Finally, a strut is preferred, which is characterized in that it is designed as a side impact protection strut for a front door, as Beulstrebe for a lock area of a vehicle door, as a strut brace for a strut, as a cross member attachment, or as a tunnel strut. Particularly preferably, the strut is designed as an elongated side impact protection strut. In one embodiment of the strut, which is designed as a Beulstrebe, preferably a part of a curb of the vehicle door is forged on the strut or forged to the strut. The term "forging out" refers to the fact that the corresponding part of the curb is integrally formed during massive forming, preferably forging, from the material of the light metal blank used for the strut. The term "forging" suggests that a separate part in massive forming, preferably in forging, is tied to the light metal blank from which the strut is integrally formed by forging the two parts together. In this case, a cohesive and / or a positive connection of the two parts is preferably created. In particular, when the parts are formed material equal to each other, it is during massive forming, preferably during forging, readily possible to effect a cohesive connection, so that ultimately a one-piece element is formed.

The object is also achieved by providing a method for producing a strut for a vehicle made of a light metal or a light metal alloy with the steps of claim 7. The method is characterized in that the strut is made in one piece from a light metal blank by massive forming, preferably forging. This results in the advantages that have already been explained in connection with the strut.

Preferred is a method in which the strut is made of a single light metal blank in one piece by massive forming, preferably by forging.

A method is also preferred, which is characterized in that along the strut load paths are determined with respect to a predetermined use of the strut, wherein the strut during massive forming, preferably during forging, is recessed locally in at least one area which is free of load paths is. Thus, it is preferred to predetermine use of the strut prior to massive forming, especially forging, and determining load paths along the strut for that predetermined use that occur in the predetermined use. Subsequently, at least one area is identified in which no load path runs or which is free of load paths. The forming process is then preferably tuned so that the strut is blanked out during massive forming or forging in the area that is free of load paths. In this way, a strut with truss structure is formed as needed, which is tuned to expected load paths out and thus at the same weight-optimized and stable.

A method is also preferred that is characterized in that the strut is heat-treated at least in regions. The material properties of the strut can be adapted to the predetermined use by means of a locally required heat treatment. Thus, it is possible to tailor the material properties of the strut area by area, in particular, this is partially or locally heat treated.

Finally, a method is preferred which is characterized in that the strut is produced by hot massive forming. An integrated heat treatment preferably takes place during hot massive forming. This eliminates a separate heat treatment step, which simplifies the process, makes it faster and cost-effective.

In a preferred embodiment of the method, it is possible that the strut after the massive forming, in particular the forging, is at least partially mechanically reworked. It is particularly possible that the strut is mechanically reworked at interfaces or joints to neighboring components of a motor vehicle bodyshell structure to facilitate the connection to the neighboring components.

In a particularly advantageous development of the invention, the strut is hybrid-forged from at least two different materials, that is to say a light metal such as aluminum and, for example, steel or a fiber-reinforced plastic. As a result, the mechanical properties of the strut can be further improved and the weight when using FVK CFK particular be further reduced, which is very beneficial to the lightweight design.

The description of the strut on the one hand and the method on the other hand are to be understood as complementary to each other. In particular, method steps that have been explained explicitly or implicitly in connection with the strut, preferably individually or in combination with each other, steps of a preferred embodiment of the method. Conversely, features that have been described explicitly or implicitly in the context of the method are preferably features of a preferred embodiment of the strut, individually or in combination with each other.

The invention will be explained in more detail below with reference to the drawing. Showing:

1 a first embodiment of a strut;

2 a second embodiment of a strut, and

3 a third embodiment of a strut.

1 shows a first embodiment of a strut 1 , which is designed as Beulstrebe for a motor vehicle rear door. The strut is made of a light metal blank in one piece by forging.

The strut 1 includes recesses 3 which are provided in areas along which no load paths run. This indicates the strut 1 Overall, a framework structure 5 on, whereby it is designed to optimize weight and at the same time load-appropriate.

2 shows a second embodiment of a strut 1 , which is designed as a side impact protection strut and in particular elongated. Also in this case, the strut points 1 a truss structure 5 so that they are weight-optimized and at the same time able to withstand high mechanical loads as required is trained. The strut 1 here includes a profiled, central area 7 , as well as flattened forged end areas 9 . 9 ' , which are preferably used for connection to adjacent elements of a motor vehicle shell structure. Such partially profiled and flat in other areas structures can be readily in the massive forming, especially forging produce.

3 finally shows a third embodiment of a strut 1 , Here is the strut 1 designed as a strut brace. In this case, it has a rounded central area 7 as well as also flattened end areas 9 . 9 ' with mounting holes 11 . 11 ' on, with the mounting holes 11 . 11 ' preferably during massive forming, in particular during forging, on the strut 1 be formed.

It is also an embodiment of the strut 1 possible, in which this is designed as part of a bumper. A variety of other possible embodiments for the strut 1 are possible.

Overall, it shows that the strut 1 at the same time lightweight and mechanically heavy-duty. It is inexpensive to produce in the process with little effort.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102004005323 B3 [0002]

Cited non-patent literature

• EN-AW 6182 [0008]

Claims (10)

Strut ( 1 ) for a vehicle, wherein the strut ( 1 ) comprises a light metal or a light metal alloy, characterized in that the strut ( 1 ) is made of a light metal blank in one piece by massive forming, preferably by forging. Strut ( 1 ) according to claim 1, characterized in that the strut ( 1 ) Aluminum or an aluminum alloy, preferably an aluminum wrought alloy, wherein the strut ( 1 ) preferably consists of one of said materials. Strut ( 1 ) according to one of the preceding claims, characterized in that the strut ( 1 ) along its extension, preferably along its longitudinal extent, a varying wall thickness or cross-sectional area. Strut ( 1 ) according to one of the preceding claims, characterized in that the wall thickness of the strut ( 1 ) is at least 1 mm to at most 3 mm, preferably at least 1.5 mm to at most 2.5 mm, particularly preferably 2 mm. Strut ( 1 ) according to one of the preceding claims, characterized in that the strut ( 1 ) at least one recess ( 3 ), wherein preferably at least one area is cut out, which is free of load paths, wherein the strut ( 1 ) preferably a framework structure ( 5 ) having. Strut ( 1 ) according to one of the preceding claims, characterized in that the strut ( 1 ) is formed as in particular elongated side impact protection strut for a front door, as Beulstrebe for a lock area of a motor vehicle door, as a strut brace for a strut of a motor vehicle, as a cross member attachment, or as a tunnel brace. Method for producing a strut ( 1 ) for a motor vehicle made of a light metal or a light metal alloy, characterized in that the strut ( 1 ) is made in one piece from a light metal blank by massive forming, preferably by forging. A method according to claim 7, characterized in that load paths along the strut ( 1 ) with regard to a predetermined use of the strut ( 1 ), the strut ( 1 ) in massive forming, especially in forging, is locally recessed in at least one area that is free of load paths. Method according to one of claims 7 and 8, characterized in that the strut ( 1 ) is at least partially subjected to a heat treatment. Method according to one of claims 7 to 9, characterized in that the strut ( 1 ) is produced by hot massive forming, wherein preferably an integrated heat treatment of the strut ( 1 ) is performed during hot massive forming.

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