WO2006058677A1

WO2006058677A1 - Method and device for producing a multichamber profile

Info

Publication number: WO2006058677A1
Application number: PCT/EP2005/012666
Authority: WO
Inventors: Kai-Uwe Dudziak; Uwe Hardtke; Carsten Rogowski; Matthias Schroeder
Original assignee: Daimlerchrysler Ag
Priority date: 2004-12-03
Filing date: 2005-11-26
Publication date: 2006-06-08
Also published as: DE102004058362B3

Abstract

The invention relates to a method and device for producing a multichamber profile, wherein a hollow semi-finished profile (1, 31, 47) provided with at least two chambers (2, 3, 45, 46) divided by a web (6, 34) is extrusion shaped. Subsequently, the semi-finished profile (1, 31, 47) is plastically expanded by a high internal fluidic pressure produced in the two chambers (2, 3, 45, 46) in an internal high-pressure moulding tool for obtaining the final shape of the hollow profile. The aim of said invention is to produce the multichamber profile in a simple manner by a reliable process even at a high deformation degree. Said aim is attained by the fact that recesses (7, 8, 9) are produced during extrusion in the sidewalls (4, 5) and in the web (6, 34) of the semi-finished profile (1, 31, 47), respectively and are closed by means the high internal pressure. For this purpose, the axial die (10, 35, 48) of an internal high-pressure moulding unit has a recessed sealing contour corresponding to the peripheral contour of the semi-finished profile (1, 31, 47).

Description

DaimlerChrysler AG

Method and device for producing a multi-chamber profile

The invention relates to a method for producing a multi-chamber profile according to the preamble of claim 1 and an apparatus for carrying it out according to the preamble of claim 3.

A generic method and a corresponding device to it is known from DE 199 09 929 Al. In this case, an extruded hollow section semi-finished product, which is provided with a double chamber, fed to a hydroforming tool by it is to be widened into the desired final shape. For sealing an axial plug in one end each of the hollow semi-finished product, it is inserted, wherein the '^"axial plug for this purpose has two sealing heads which are immersed in each case one chamber of the hollow profiled semi-finished product. The sealing heads consist of an elastomer and each include a surface plate, which in position of use The straightening plates are intended to prevent unwanted curvature of the web during hydroforming, in each of which a pressurized fluid supply line leads, through which each chamber can be filled with a pressurized fluid and a fluid high pressure can be generated To allow the deformation to proceed uniformly, are in the web through holes provided over which the pressure fluid can pass from one chamber to the other, so that a pressure equalization is ensured. In such a design of the hollow profile semi-finished product, however, it is disregarded that the web acts like a tie rod on the remaining regions of the hollow profile during the forming. By this property, the elongation of the semifinished product is limited to a considerable extent, so that only small degrees of deformation can be made possible in the expansion. However, if an attempt is made to achieve higher degrees of deformation during the expansion, the semi-finished product is ironed over the web, which leads to crack formation in the web and in all side walls of the semifinished product. As a result, the process reliability of the production of the desired double-chamber profile is seriously endangered. Another unsightly effect of the web on the deformation of the semi-finished product is that after a successful reshaping the hollow profile material elastically springs back to a certain extent just in the transition region of the web to the side walls of the hollow profile, which forms sink marks in the hollow profile contour. Furthermore, it should be said that it is technically possible, especially for a large-scale production, if at all - only with very great effort is possible to provide relatively deep lying in the hollow profile through holes in the web.

The early ironing of the web can be circumvented according to DE 199 09 924 C2 in that the extruded semi-finished product of the double-chamber hollow profile is formed in the web area with a larger cross-section than in other areas of Doppelkammerhohlprofilhalbzeugs. However, since in the method shown in the document, no large degrees of deformation must be accomplished and the expansion in the web area is low, neither serious sink marks in the transition region of the web to the side walls still problems in the remaining areas of the double-chamber hollow profile in the expansion to be expected. However, if the hollow profile material has to bridge larger expansion distances to achieve complex component designs, the double chamber hollow profile will fail very quickly in the known method, since the web area in cross section is significantly larger than the remaining hollow profile areas and thus the distances to be overcome are also increased the material thinning is particularly strong.

The invention has the object of developing a generic method and apparatus to the effect that a multi-chamber profile can be produced process reliable in a simple manner, even with large degrees of deformation.

The object is achieved by the features of claim 1 with respect to the method and by the features of claim 3 with respect to the device.

Thanks to the inventive shaping of the side walls and the web during extrusion, which manifests itself in indentations, material depots are created in the semifinished product, which are pushed out during expansion by internal high pressure. As a result, an early ironing of the hollow profile is prevented in a simple manner, so that expansion with large degrees of deformation can be achieved without cracks forming in the walls and thus the process reliability would be endangered. The recess depth is designed so that when reaching the desired final shape of the multi-chamber hollow profile, the respective material depot is used up. Due to the fact that the web is merely stretched during the expansion and does not have to scoop any material from its wall thickness, even after the expansion has been completed and pressure relief in the web area no visible spring back, which would be expressed in sinks. In order to carry out the process in accordance with the process, the corresponding device has an axial punch which seals off the ends of the semifinished product and has a recessed sealing contour corresponding to the peripheral contour of the semifinished product. The Axialstempel is pushed onto the end, which results in the resulting plug connection between the Axialstempel and the hollow profile semi-finished a metallic seal. In order to obtain the desired shape of the multi-chamber hollow profile, it is conceivable that the engraving of the hydroforming against the end shape of the multi-chamber hollow profile to be achieved has a slight oversize, so that although after expansion of the multi-chamber hollow profile and his investment in the engraving a multi-chamber hollow profile Oversity forms, but after the pressure relief and the elastic resilience of the hollow profile material exactly the desired final shape of the multi-chamber hollow profile occupies.

In a preferred embodiment of the invention according to claim 2 and claim 4, the web is cut out at the end of the hollow profile semi-finished product. The Axialstempel has to a single sealing head, which carries the Abdichtkontur. As a result, a particularly simple form of the seal is achieved, wherein the web must be cut out only over a freely selectable stretch section, so that the axial punch with its sealing head can be pushed effortlessly into the multi-chamber profile. Because the sealing head has a slight oversize relative to the cross section of the end of the multi-chamber profile semi-finished product and that the sealing head is designed for easier insertion into the semifinished product in the manner of a truncated cone, in which only a rear portion has the excess, the axial punch becomes metallic with the semifinished product Pressed, so that is a special good sealing during expansion by means of internal high pressure can be achieved.

A further preferred embodiment of the device according to the invention is shown in claim 5, wherein the axial punch has an end face projecting from the edge annular tooth, which is designed with the Abdichtkontur. As a result, the formation of the device is considerably simplified, as can be dispensed with a sealing head on Axialstempel. The Axialstempel takes over alone the sealing function, where he is not pushed into the hollow section semi-finished, but drives his ring teeth in the face of the front side of the end of the hollow section semi-finished product. In addition, the manufacturing process is simplified, since no removal of the web in the docking area of Axialstempels is required. In order to meet the indented pre-profiling of the hollow section semi-finished product, the ring point is equipped with a correspondingly formed Abdichtkontur.

In a further, particularly preferred embodiment of the invention according to claim 6, the axial punch on the end face a single outflow opening of a pressure fluid channel, which partially covers the cross-sectional area of all chambers. Here, the Axialstempel is also simplified in particular, since only a single Abdichtkopf must be formed with only a single outflow and not as usual several Abdichtköpfe, each associated with a chamber and must be threaded into this with considerable effort. Due to the special design of the outflow opening, which can be circular with large diameter, elliptical or slit-like, all chambers can be filled simultaneously with a pressurized fluid. Furthermore, the same internal high pressure is simultaneously generated in a simple manner in all chambers, so that Combined expansion of the hollow section semifinished material can proceed evenly. Elaborate processing steps of the web by the introduction of perforations for the passage of the pressurized fluid from one chamber to the other omitted.

In a further preferred embodiment of the device according to the invention according to claim 7, the axial punch for each of the chambers has a separate sealing head, wherein the Abdichtköpfe each have recessed Abdichtkonturen for each chamber and wherein adjacent Abdichtköpfe are spaced from each other by a gap. The shape of the gap is adapted to the curved course of the next in it with much play coming bridge. Each of the sealing heads has its own outflow opening of a pressure fluid channel. Characterized in that each chamber is associated with a sealing head of Axialstempels, which has its own outflow opening of a pressure fluid channel, the chambers of the hollow section semifinished can be filled faster, so that the manufacturing process of the multi-chamber profile is shortened and thus more effective. Since each sealing head has its own discharge opening, a separate pressure fluid channel can be provided for each sealing head. This makes it possible to act on the individual chambers with different pressures, so that the hollow profile semi-finished product can be selectively expanded differently on different walls. This is for example advantageous if the chambers have a different wall thickness, so that the thinner walls are not acted upon by a high pressure and thereby tear before reaching the desired final shape by excessive material thinning. For this case, different wall thicknesses, the process reliability remains due to the formation of multiple Abdichtköpfe and separate outflow openings with separate pressure fluid channels in the production of a multi-chamber profile. At the same Wall thicknesses, it may be useful to pressurize the individual chambers with different pressure when the walls are to be exposed to different degrees of deformation locally. Here, the walls, which have to cope with a low degree of deformation, be subjected to a lower pressure than other walls, which experience a higher degree of deformation. It is thereby achieved that the walls, in which a low degree of deformation is required, do not come too early to the engraving to the plant, which would cause the onset of friction between the expanded hollow section and the hydroforming die, which for the expansion of the walls with greater degree of deformation would be inhibitory. As a result of the spacing of the Abdichtköpfe a gap is created in which the respective web of the hollow section semifinished product can be accommodated. As a result, insertion of the sealing heads in the chambers of the hollow profile semi-finished product is made possible. Due to the clearance between the web and the Abdichtköpfen this can extend freely and unhindered during the expansion of the hollow profile semi-finished product.

A further, particularly preferred development of the invention according to claim 8 is that the pressure fluid ducts adjoining the outflow openings of the sealing heads are fluidically connected to one another in the axial punch by a transverse bore. This is advantageous for the case in which the hollow profile semi-finished product is to be widened uniformly and the axial punch has said sealing heads which are to be pushed into the chambers of the hollow profile semi-finished product. As a result of the transverse bore within the Axialstempels, which fluidly connects the pressure fluid ducts with each other, there is always a pressure equalization between the chambers of the hollow profile semi-finished product during the expansion in a simple manner. As a result, the hollow profile semi-finished product can be reliably expanded into the desired final shape of the multi-chamber profile. The invention is explained in more detail with reference to several embodiments shown in the drawings.

Showing:

1 is a perspective view of a Vorprofiliertes hollow profile semi-finished product according to the invention and a portion of a Axialstempels a device according to the invention with two Abdichtköpfen in non-use position of Axialstempels,

2 in a lateral longitudinal section of the axial punch of Figure 1 with a two pressure fluid channels connecting transverse bore in the operating position of the Axialstempels,

3 is a perspective view in broken-away view of an inventive pre-profiled hollow profile semi-finished product with partially removed web and an axial punch of a device according to the invention with a single sealing head in non-use division,

4 is a perspective view of a pre-profiled semifinished semi-finished product according to the invention and an axial punch of a device according to the invention without a sealing head, but with a ring tooth in the non-use position.

1 shows a semi-finished hollow section 1 of a multi-chamber profile with two chambers 2, 3, which was extruded in an extrusion die. The hollow section semifinished product 1 was inventively pre-profiled, whereby on the side walls 4 and 5 and the web 6, which separates the two chambers 2 and 3 from each other, recesses 7,8,9 are formed. Subsequently, the hollow profile semi-finished product 1, the For example, an aluminum extruded profile can be supplied to a hydroforming system that includes a split forming tool. In the cavity of this tool, the hollow section semi-finished product is inserted, after which the tool is closed. Subsequently, an axial punch 10 is pushed into one side of the hollow profile semi-finished product 1 in the local end 11. For this purpose, the axial punch 10 has two sealing heads 12 and 13, which are designed in the shape of a truncated cone and taper towards the hollow profile semi-finished product 1.

The common outer contour of the two sealing heads 12 and 13 corresponds approximately to the peripheral contour of the hollow profile semi-finished product 1, wherein an upper side 14 of the sealing head 12 and a bottom 15 of the sealing head 13 the recesses 7 and 8 of the hollow section semifinished product 1 corresponding concaves 16 and 17 have. The two sealing heads 12 and 13 are spaced from each other by a gap 18 whose shape is adapted to the curved course of the web 6 of the hollow profile semi-finished product 1. For this purpose, the sealing head 13 has on its upper side 19 a concavity 20, while the underside 21 of the sealing head 12 has a convex bulge 22. The Abdichtköpfe 12 and 13 are set back from the edge 23 of the Axialstempels 10 inside, so that the freed by the distance between the Abdichtköpfen 12 and 13 and the edge 23 surface a circumferential axial stop 24 for the axial punch 10 on the end face 25 of the end eleventh the hollow section semi-finished product 1 is formed.

When inserting the Axialstempels 10 in the hollow section semi-finished product 1, the two sealing heads 12 and 13 dip into the chambers 2 and 3 until the axial stop 24 of the Axialstempels 10 comes to rest on the end face 25 of the semi-finished hollow profile end 11. In the abutment area, the sealing heads 12 and 13 face the inside of the chambers 2 and 3. Measured, whereby the hollow profile semi-finished product 1 is squeezed between the Abdichtköpfen 12 and 13 and the surrounding tool engraving, resulting in a high-pressure-tight metallic compression. Each of the Abdichtköpfe 12 and 13 has the front side approximately centrally located an outflow opening 26 of a pressure fluid channel 27, as can be seen also from Figure 2. The two pressure fluid channels 27 are fluidly connected to each other by a transverse bore 28 which extends in the axial punch 10 and on the outer side 29 of the Axialstexnpels 10 has a connection 30 to a fluid supply. In the use position of the Axialstempels 10, in which the two Abdichtköpfe 12 and 13 are immersed in the chambers 2 and 3 and the hollow profile semi-finished product 1 is crushed at its end 11 between the Abdichtköpfen 12,13 and the tool engraving, the chambers 2 and 3 with a Pressure fluid via the fluid port 30 and the transverse bore 28 and the pressure fluid channels 27 of the axial punch 10 filled. Thereafter, set by a not shown here fluid high pressure generating system under high pressure, whereby the hollow profile semi-finished product 1 expands until it comes to the tool engraving to the plant. Here, the web 6 and the side walls 4 and 5 of the hollow profile semi-finished product 1 stretches, wherein the indentations 7 to 9 are pushed out. While the web 6 is thereby smooth, take the side walls 4 and 5, the contour of the mold cavity of the hydroforming. After this plastic widening, the hollow profile end shape of the multi-chamber profile is essentially achieved, the receipt of which after the pressure release and the springback of material in the elastic region is then completely completed. After production, the axial punch 10 is pulled out of the multi-chamber profile into its non-use position.

In a variant of the invention, FIG. 3 shows a hollow profile semifinished product 31 in which, in contrast to the hollow profile semifinished product 1 of the previous embodiment at the end 32 has a recess 33 of the web 34, which is effected by separating out, in particular by laser cutting or sawing. Through this recess 33, the axial punch 35 can be pushed into the hollow profile semi-finished 31 in a simple manner, the axial punch 35 having a single large sealing head 36 which dips into the recess 33 and the Abdichtkontur with a concave 37 each at its top 38 and its Bottom 39 according to the contour of the hollow profile semi-finished 31 carries. The sealing head 36 is set back from the edge 40 of the Axialstempels 35 inwardly, wherein the resulting free surface forms an axial stop 41 for the Axialstempel 35 on the end face 42 of the semi-finished hollow profile end 32.

Notwithstanding the previous embodiment, the sealing head 36 has on its end face 43 a single outflow opening 44 with a large, circular cross-section, which adjoins a pressure fluid channel extending in the axial ram 35. The shape and the cross-sectional area of the outflow opening 44 are selected such that they partially cover the cross-sectional area of the chambers 45 and 46 of the hollow profile semi-finished product 31. In this case, the web 34 separates the outflow opening 44, as it were, into two partial openings, one of which is assigned to one of the chambers 45 and 46. The further method step for producing the multi-chamber profile with respect to the widening is here the same as in the previous embodiment, wherein in the position of use of the Axialstempels 35 of the sealing head 36 is not in the chambers 45 and 46, but in the recess 33 inserted.

As a further variant of the invention shows the same design of the hollow section semi-finished product 47 as in the first embodiment, Figure 4 an axial punch 48 without sealing head an incorporated in its end face 49 outflow opening 50 for a subsequent to this pressure fluid channel. Unlike the previous embodiments, the axial punch 48 for sealing the hollow profile semi-finished product 47 has an axially projecting from its edge 51 annular prong 52 which is configured with the Abdichtkontur. To assume its position of use of the axial punch 48 is moved up to the hollow profile semi-finished product 47, wherein the punch 48 digs with its ring teeth 52 in the surface of the end face 53 of the hollow profile semi-finished product 47 and thus forms a high pressure-tight metallic seal. The outflow opening 50 is otherwise formed and arranged in the same way as the outflow opening 44 in the previous embodiment of Figure 3 and fulfills the same function. Finally, a connection 55 can still be seen in a side wall 54 of the axial punch 48, to which a pressure fluid line can be connected.

Claims

claims

1. A method for producing a multi-chamber profile, wherein a hollow profile semi-finished product is formed by at least two chambers separated by a web by extrusion and then by means of fluidic internal high pressure, which is generated in both chambers, is plastically expanded in an internal high pressure forming tool in a Hohlprofilendform, characterized characterized in that the extrusions on the side walls (4,5) and the respective web (6,34) of the hollow profile semi-finished product (1,31,47) indentations (7,8,9) are formed and that they are then pushed out by means of internal high pressure ,

2. The method according to claim 1, characterized in that the web (34) at the end (32) of the hollow profile semi-finished product (31) is separated out.

3. Apparatus for producing a multi-chamber hollow profile, comprising an extrusion tool for producing a hollow profile semi-finished product with at least two chambers separated from one another by a web, and having an internal high-pressure forming installation which includes a split tool, in the mold space, the semifinished product for expanding expansion is introduced, and having the ends of the semi-finished sealing axial punch for performing the method according to claim 1, characterized in that the axial punch (10,35,48) has a recessed Abdichtkontur that the peripheral contour of the hollow profile semi-finished product (1,31,47) corresponds.

4. Apparatus according to claim 3, characterized in that the axial punch (35) has a single in the web-free end (32) of the hollow profile semi-finished product (31) hineinschiebbaren sealing head (36) which carries the Abdichtkontur.

5. The device according to claim 3, characterized in that the axial punch (48) has an end side of the edge (51 projecting annular tooth (52), which is designed with the Abdichtkontur.

6. Device according to one of claims 4 or 5, characterized in that the axial punch (35,48) frontally a single outflow opening (44,50) of a pressure fluid channel having the cross-sectional area of all chambers (2,3,45,46) partially covered.

7. The device according to claim 3, characterized in that the axial punch (10) for each of the chambers (2,3) has a separate sealing head (12,13), wherein the Abdichtköpfe (12,13) each indented Abdichtkonturen for the individual chambers (2, 3) and wherein adjacent sealing heads (12, 13) are spaced from one another by a gap (18) whose shape is adapted to the curved course of the web (6) coming into contact with it with much play , And that each of the Abdichtköpfe (12,13) has its own outflow opening (26) of a pressure fluid channel (27).

8. The device according to claim 7, characterized in that the at the outflow openings (26) of the Abdichtköpfe (12,13) subsequent pressure fluid channels (27) in the axial punch (10) by a transverse bore (28) are fluidly connected together.