WO2009068129A1

WO2009068129A1 - Support structure and method for the production thereof

Info

Publication number: WO2009068129A1
Application number: PCT/EP2008/007697
Authority: WO
Inventors: Kai-Uwe Dudziak; Dieter Junge; Thorsten Wichmann; Jürgen Falke
Original assignee: Daimler Ag
Priority date: 2007-11-30
Filing date: 2008-09-16
Publication date: 2009-06-04
Also published as: DE102007057724A1

Abstract

The invention relates to a support structure (1, 36) comprising at least two hollow profiles (2, 3, 4) connected to one another in a positive fashion. In order to attain a high degree of stability for the support structure (1, 36) and, at the same time, a high structural variability in a relatively simple fashion, the invention proposes that a first hollow profile (2, 20) extending transversely to the second hollow profile (3, 25) be designed as an extrusion-molded profile having at least two chambers (6, 7, 8, 9, 24, 34) running parallel to the second hollow profile (3, 25) and separated from one another by a separating wall (5, 12, 26), wherein the second hollow profile (3, 25) through which the one chamber (9, 24) extends is accommodated there in a positive fashion and is encompassed by the first hollow profile (2, 20).

Description

Supporting structure and a method for its production

The invention relates to a support structure according to the preamble of claim 1 and a method for their preparation according to the preamble of claim. 7

A generic support structure and a method for their preparation is known from DE 195 19 353 Al. For this purpose, a first tubular or pre-profiled hollow profile is inserted into a multi-part tool and expanded by fluidic internal high pressure, whereby the first hollow section is finished. As a result of the deformation, the first hollow profile has a channel-shaped receptacle. Then, after opening the internal high-pressure forming tool, a second tubular or pre-profiled hollow profile is inserted into the receptacle of the first, the tool is closed with a new upper part and the second hollow profile is inflated by fluidic internal high pressure. In this case, this is widened into the receptacle and creates a form-fitting on the wall. In a further exemplary embodiment according to FIG. 8, the first outer hollow profile is crimped and has a central tubular receptacle for the second inner hollow profile, which projects through the first hollow profile.

The invention has the object of developing a generic support structure to the effect that a high stability of the support structure with a high structural variability is achieved in a relatively simple manner without additional stiffening components. Of Furthermore, a method for their preparation is to be specified.

The object is achieved by the features of claim 1 with respect to the support structure and by the features of claim 7 with respect to the method.

The fact that the support structure according to the invention consists of at least two hollow profiles, which are connected by positive engagement with each other and in which the first hollow profile surrounds the second, a high stability of the construction is achieved against externally acting mechanical forces. By reshaping the second hollow profile by means of internal high pressure, a nearly complete conformal system is achieved on the inside of the first hollow profile, whose cross section deviates from a circular shape, so that a positive connection is formed, in which the hollow profiles are held against rotation against each other. The fact that the second hollow profile extends through the first, this is also taken captive in the first hollow profile. The hollow sections are practically no longer detachable from each other without any of the two hollow sections being damaged. In order to satisfy the design diversity and thus the constructive variability of the support structure in a simple manner, the first hollow section is formed as an extruded profile with at least two separate from each other by a partition chambers. Although the extruded profile extends in the transverse direction to the second hollow profile, but the chambers are parallel to the second hollow profile. In an end-side chamber of the extruded profile while the second hollow profile, which projects through this, received positively. With the formation of the second hollow profile as a multi-chamber extruded profile, the construction of an expansive, yet stable support structure is made possible, which at the location of the extruded profile due to its framework character very torsionally rigid and in the field the second hollow section is particularly torsionally rigid and rigid by its tubular shape. With very little effort the profiles are pushed into each other, or pushed the second hollow section through the first, after which then the sliding assembly is exposed to a fluidic internal high pressure. Depending on requirements, the sliding assembly can be achieved within or already outside the forming tool. By suitable pressure control, it is not absolutely necessary that a support pressure is maintained in the adjoining the receiving chamber chamber of the extruded profile. The extruded profile can be designed very complex and used in motor vehicle for connection to other components such as steering console, console of the A-pillar or tunnel strut, while the tubular hollow profile can act as a longitudinal or cross member. In this context, the extruded profile for joining offers favorable surfaces, in particular joining flanges can be formed.

To further expand the support structure and further increase the stability due to an improved force distribution in an incoming force from the outside, the second hollow profile can be encompassed in its axial course of several first hollow sections at different locations. Even with such a multi-part design of the support structure only a single forming tool is required. The apparatus and pressure control technical effort is - except for the enlargement of the tool and its component holder - low, since only the inner second hollow section is placed under internal high pressure. Finally, the extruded profile in the form of a console on a much better crash behavior compared to the usual very rigid die-cast consoles, since the extruded profile can absorb much better crash energy by deformation. Due to the direct connection of the two hollow profiles to each other no additional stiffening plates or the like are required, resulting in a reduction of the weight and the number of components. Furthermore, fastening elements and corresponding joining methods, in particular welding methods, which cause distortions in the supporting structure and therefore entail complicated straightening work, can be dispensed with.

In an advantageous development of the invention according to claim 2, the second hollow profile has a plug-in element, preferably designed as a flange, which preferably dips into a pocket formed in the chamber to form a press fit. As a result, not only a further positive connection between the two hollow profiles is created but also achieved a frictional engagement between these two, whereby the risk of any possible slipping out of the second hollow section of the first at least hindered, if not avoided depending on the strength of the interference fit. Thus, the stability of the supporting structure is further improved. The plug element can be attached to the tubular hollow profile. However, in order to ensure a particularly good durability, which is also durable with respect to mechanical loads, it is advantageous if the plug-in element is an integral part of the second hollow profile. This can be achieved by a molding out of the hollow profile, whereby very different versions of the plug element can be realized, such as in the form of knobs, pins, nozzles or elongated strips. Alternatively, it is conceivable to also produce the second hollow profile as an extruded profile, wherein the plug-in element is designed as a flange. This requires a lower production cost, since at the same time the flange is produced with the production of the hollow profile. It is also conceivable to produce the flange by appropriate design of the second profile as a roll or rolled profile, wherein the so rolled or rolled Hollow profile is then welded longitudinally. In a preferred embodiment of the method according to claim 9 according to the invention is carried out in a simple manner the insertion by means of the expansion of the inner second hollow section hydroforming, it is favorable to choose the inside width of the pocket of the first hollow profile slightly smaller than the outer dimension of the plug element, so that the penetration of the bag is facilitated, but nevertheless a sufficiently strong interference fit is ensured.

In a preferred embodiment of the invention according to claim 8, the first hollow profile, but only elastic, is expanded during the plastic expansion of the second hollow profile. After relaxing the internal high pressure, the outer first hollow profile elastically springs back, which forms an extremely strong frictional interference fit with the plastically no longer reshaping inner second hollow profile, which further increases the stability of the support structure and the release of the hollow sections from each other even more difficult. In this case, this measure is also weight neutral, ie without Zuatzbauteile, and can be executed in procedural economic manner in one operation with the expansion process of the second hollow section and in the same forming tool.

In a further particularly preferred embodiment of the invention according to claim 3, the first hollow profile outside of the projecting portion of the second hollow profile is axially enclosed. This represents a further increase in the stability of the supporting structure, since now also an axially acting positive locking is achieved. As a result, a movement of the second hollow profile relative to the first and thus a release of the support structure further difficult. The enclosure can be done as a result of the internal high pressure induced widening of the second hollow profile or in a subsequent operation by widening of the second hollow profile. In both cases the outer diameter of the second hollow profile is increased beyond the inner diameter of the first hollow profile out, wherein hollow profile material of the second hollow profile is displaced to the outside and applies to the end faces of the first hollow profile. Again, no additional fasteners or components are used, which despite increasing the stability of the weight of the support structure remains unchanged and limited only to the sum of the individual weights of the hollow sections.

In a further particularly preferred embodiment of the invention according to claims 4 and 10, the chamber receiving the second hollow profile of the first hollow profile has a longitudinal gap extending over its entire extent, where there expires the first hollow profile at least at one of the gap edges in a flange-like end. Furthermore, the second hollow profile on a mounting flange which penetrates the longitudinal gap of the chamber and at least locally abuts the flange-like end. The flange-like end and the mounting flange are then connected to each other by toxen, gluing, welding, riveting, soldering and / or by a plastic extrusion. The mounting flange may be formed on the second hollow profile component or by the hollow profile by shaping, by the design as an extruded profile or roll or roll profile followed by longitudinal seam welding. The longitudinal gap with the flange-like end of the first hollow profile can be easily represented by extrusion in the production of the first hollow profile. Of course, it is also conceivable to separate an originally circumferentially closed receiving chambers of the first hollow profile and to cut out a section of suitable width, so that the gap results. A gap edge containing the end of the first hollow profile can then be bent and flattened flange. Although the attachment of the two flanges is connected to each other with an additional operation and in the case of riveting also requires additional weight-increasing fasteners and in the case of soldering and Kunststoffumspritzung additional material, however, the two hollow sections are inextricably linked together by these joining operations, creating a very high stability and durability of the support structure is achieved. In the case of welding, the effect of the energy input with respect to the material distortions occurring on the shape of the hollow profiles is low, since this is done only at the edge. The encapsulation with plastic can lead to a pure clamping of the two flanges together. However, it is also conceivable that the flanges have openings through which the injected plastic can pass through, so that a cohesive no longer removable enclosure of the flanges is achieved. The joining of the flange can take place after hydroforming. However, it is advantageous to carry this out later, since there is a risk that during the expansion process during the

Hydroforming process, the gap further aufklafft as desired, so that a flat contact with the flanges is no longer given, which would make the joining operation considerably more difficult. The flanges allow higher-load areas to be integrated directly into the supporting structure.

In a further preferred embodiment of the invention according to claim 5, the support structure is part of a metal-plastic hybrid assembly. The integration of the support structure in the assembly fits in an advantageous manner in the concept of the construction of large-scale carcass structures without fasteners and stiffening plates with at least as good if not better functionality in terms of attachment and stability. Again, in an economical manner, the assembly with the support structure as a whole can be produced in a forming tool, wherein the same internal high pressure in achieving the positive connection for the supporting structure and the production of the metal-plastic Hybrid composite, in which the hydroforming and injection molding work together in a combination process, can be used. Furthermore, the injection molding of the composite for the production of the clip-like encapsulation of the abutting flanges of the supporting structure can also be used simultaneously here. Incidentally, the forming tool for the supporting structure may be a modified injection-molding or internal-high-pressure forming tool.

In a preferred embodiment of the invention according to claim 6 or 11, the plastic encapsulation and / or the plastic part of the metal-plastic hybrid assembly is produced by injection molding injection molding, which on the one hand contributes significantly to the weight reduction of the assembly. Furthermore, on the other hand, its rigidity is increased due to the microcellular structure of the solidified foam.

The invention is explained in more detail with reference to several embodiments shown in the drawings.

Showing:

1 is a perspective view of a support structure according to the invention with joined flanges of the hollow profiles,

2 is a side view of the support structure of FIG. 1 with a flange of the second hollow profile surrounded by two flanges of the first hollow profile, FIG.

Fig. 3 is a side view of a support structure according to the invention with a plug-in element of the second Hollow profile and a pocket of the first hollow profile,

Fig. 4 in a lateral longitudinal section in sections a support structure according to the invention with a second hollow profile axially enclosed first hollow section.

In Fig. 1 and 2, a support structure 1 is shown, which consists of three hollow sections 2,3,4, which are interconnected by positive locking. A first hollow section 2 extends in the transverse direction to the second hollow section 3 and, like the hollow section 3, is designed as an extruded profile, wherein both hollow sections 2 and 3 fundamentally differ structurally. The hollow section 2 is truss-like with three spaced apart from each other by a partition wall 5,12,26 chambers 6,7,8,9 formed, which are seen from the hollow profile 3 arranged one behind the other. The length of the hollow profile 2 from the chamber 6 to the chamber 9, which has a polygonal cross-sectional shape, is several times greater than the distance between the two openings 10,11 of each chamber 6,7,8,9. The chambers 6,7,8,9 are parallel to the second hollow section 3, which in contrast to the hollow profile 2 has an elongated circumferentially closed tube shape.

The hollow section 3 extends through the chamber 9 of the first hollow section 2 and is received in this form-fitting and thereby encompassed by the first hollow section 2. The outer side 37 of the hollow profile 3 is located in the projecting portion of the hollow section 2 over the entire circumference completely contoured on the inside 38 of the chamber 9 and is thus at least rotatably connected to the hollow section 2. The chamber 9 has in its the partition wall 12 opposite peripheral region 13 extending over its entire extent from opening 10 to opening 11 longitudinal gap 14, where there the first hollow section 2 at both gap edges 15,16 in a thicker and a thinner flange end 17,18 runs out. It is also conceivable that the gap 14 is located in a different circumferential region of the chamber 9, but outside the partition wall 12. The two ends 17, 18 of the hollow profile 2 grasp a mounting flange 19 of the second hollow profile 3 which extends over the entire longitudinal extent of the hollow profile 3 and penetrates the longitudinal gap 14 of the chamber 9 and rests flat against the flange-like ends 17, 18.

The ends 17,18 and the mounting flange 19 are connected by a plastic extrusion. In the flanges 17,18,19 through holes 29,30,31 are formed, which penetrates the plastic during the encapsulation and after solidification closely pressed together, since the plastic is subject to a certain shrinkage during solidification. The plastic can also grip the end edges of the flanges 17-19 to further improve the attachment during the overmolding so that it holds the flanges together like a ring.

The support structure 1 is here part of a metal-plastic hybrid assembly, the plastic extrusion of the ends 17,18 and the mounting flange 19 part forms the connecting portion of the support structure 1 to the remaining part of the assembly. The hollow profile 4 is formed in the same way as the hollow profile 2 and spaced parallel to this in the extension direction of the hollow profile 3. The connection between the two hollow sections 3 and 4 is also the same as between the hollow sections 2 and 3.

According to Fig. 3, the first hollow section 20 of the support structure 36 also has a longitudinal gap 21, however, in deviation from the embodiment described above, only one end 22 is formed as a flange. This is due to the comparatively much thicker mounting flange 23 in the chamber 24 of the hollow section 20 received hollow profile 25 plan. The attachment of the two flanges 23 and 22 to each other by a plastic extrusion analogous to the above embodiment. For this purpose, in the flanges 22 and 23 aligned through holes 27,28 are formed through which the injected plastic can pass through and forms a kind of anchor for the flanges 22,23. The second hollow profile 25 has a plug-in element 32, preferably formed as a flange, on a gap-facing peripheral region on the outer side 37, which in a formed in the chamber 24 by corresponding shaping of the partition wall 33 between the adjacent chamber 34 and the chamber 24 bag 35th preferably immersed to form a press fit.

As shown in FIG. 4, in addition, the first hollow profiles 2 or 20 outside the protruding portion, so the chamber 9 or 24 from the second hollow section 3 or 25 may be axially enclosed to form a further positive connection.

To produce the supporting structure 1, 36, the second hollow profile 3, 25 is pushed into a chamber 9, 24 of the first hollow profile 2, 20, the first hollow profile 2, 2 embracing the second 3, 25. The two hollow sections 2.20; 3.25 are introduced into a forming tool prior to telescoping or in sliding position, after which the second hollow section 3.25 is widened by means of high-pressure internal under contour-accurate contact with the inside 38 of the first hollow section 2.20. As a result, we achieved the non-rotatable positive connection between the hollow sections 2.20 and 3.25. It is also conceivable that during the plastic expansion of the second hollow section 3.25 and the first hollow section 2.20, however, is only elastically expanded. Due to the interference fit created in this case, an additional frictional engagement between the hollow profiles 2, 20 and 3, 25 is generated in every direction. In the case of the embodiment of Fig. 3 is by means of the internal high pressure, the plug-in element 32 formed on the outside 37 of the second hollow profile 25 is pressed into a pocket 35 formed on the first hollow profile 20 on the inside, so that the plug-in element 32 is frictionally inserted and the supporting structure 36 receives a further frictional engagement. Furthermore, it is also possible that, as shown in FIG. 4, the widening of the second hollow profile 3, 25 also takes place outside the chamber 9, 24 of the first hollow profile 2, 20, so that it encompasses the walls of the second hollow profile 3, 25 becomes. As a result of the form fit achieved, the second hollow profile 3, 25 is set axially immovably on the first one.

When inserting the second hollow section 3.25 in the first is to make sure that the mounting flange 19,23 penetrates the longitudinal gap 14,21 of the first hollow section 2,20. Then the mounting flange 19,23 and the ends 17,18,22 of the first hollow section 2,20 are connected via the passage openings 27- 31 by a plastic extrusion.

To the support structure 1.36 a die-cast part 39 is mounted in use as a steering console, in particular screwed. However, it is also conceivable to produce this component by injection molding, and this can be integrated into the manufacturing process of the metal-plastic hybrid assembly with.

Claims

claims

1. supporting structure, which consists of at least two hollow profiles which are interconnected by positive locking, characterized in that a first in the transverse direction to the second hollow profile (3,25) extending hollow profile (2,20) as an extruded profile with at least two from each other by a Separate wall (5,12,26) is formed parallel to the second hollow profile (3,25) extending chambers (6,7,8,9,24,34), wherein the second hollow profile (3,25), which is the one chamber (9,24) penetrates, received there form-fitting and from the first hollow profile (2,20) is embraced.

2. Supporting structure according to claim 1, characterized in that the second hollow profile (25) has a plug element (32), preferably designed as a flange, which dips into a chamber (24) formed pocket (35) preferably to form a press fit ,

3. Supporting structure according to one of claims 1 or 2, characterized in that the first hollow profile (2,20) outside of the projecting portion of the second hollow profile (3,25) is axially enclosed.

4. Supporting structure according to one of claims 1 to 3, characterized

in that the chamber (9, 24) of the first hollow profile (2, 20) accommodating the second hollow profile (3, 25) has a longitudinal gap (14, 21) extending over its entire extension, the first hollow profile (2, 20) there being at least at one of the gap edges (15,16) terminates in a flange-like end (17,18,22),

- That the second hollow profile (3,25) has a mounting flange (19,23) which penetrates the longitudinal gap (14,21) of the chamber (9,24) and at least locally abuts the flange-like end (17,18,22),

- And that the end (17,18,22) and the mounting flange (19,23) are connected to each other by Toxen, gluing, welding, riveting, soldering and / or by a plastic extrusion.

5. Supporting structure according to one of claims 1 to 4, characterized in that the supporting structure (1,36) is part of a metal-plastic hybrid assembly.

6. Supporting structure according to one of claims 4 or 5, characterized in that the plastic extrusion and / or the plastic part of the metal-plastic hybrid assembly consists of foam injection molding.

7. A method for producing a support structure, wherein two hollow profiles are connected by hydroforming of one of the two hollow profiles form-fitting manner, characterized

- That a second hollow profile (3,25) in a chamber (9,24) of a first with at least two chambers (6,7,8,9,24,34) formed by extrusion Hollow profile (2,20) is pushed, wherein the first hollow profile (2,20) engages around the second,

- that the two hollow profiles (2, 20, 3, 25) are introduced into a forming tool prior to telescoping or in sliding position,

- And that the second hollow profile (3,25), by means of internal high pressure under contour-accurate contact with the inside (38) of the first hollow profile (2,20) is widened.

8. The method according to claim 7, characterized in that during the plastic expansion of the second hollow profile (3,25) and the first hollow profile (2,20), but only elastically, is widened.

9. The method according to any one of claims 7 or 8, characterized in that by means of the internal high pressure on the outer side (37) of the second hollow profile (3,25) formed plug element (32) in one on the first hollow profile (2,20) formed inside Pocket (35) is frictionally inserted.

10. The method according to any one of claims 7 to 9, characterized in that a mounting flange (19,23) of the second hollow profile (3,25) extending over the entire extent of the chamber (9,24) extending longitudinal gap (14,21 ) penetrates the first hollow profile (2,20), with at least one of the gap edges (15,16) flange-like end (17,18,22) of the first hollow profile (2,20) by Toxen, gluing, welding, riveting, soldering and / or is connected by a plastic extrusion.

11. The method according to claim 10, characterized in that the plastic extrusion is produced by foam injection molding.